commit 470490fc5be70bf62d10475f6af0942d9047a67b Author: krjan02 Date: Wed Dec 10 14:26:45 2025 +0100 Initial commit diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..2d0c392 --- /dev/null +++ b/.gitignore @@ -0,0 +1,137 @@ +# Byte-compiled / optimized / DLL files +__pycache__/ +*.py[cod] +*$py.class + +# C extensions +*.so + +# Distribution / packaging +.Python +build/ +develop-eggs/ +dist/ +downloads/ +eggs/ +.eggs/ +lib/ +lib64/ +parts/ +sdist/ +var/ +wheels/ +pip-wheel-metadata/ +share/python-wheels/ +*.egg-info/ +.installed.cfg +*.egg +MANIFEST + +# PyInstaller +# Usually these files are written by a python script from a template +# before PyInstaller builds the exe, so as to inject date/other infos into it. +*.manifest +*.spec + +# Installer logs +pip-log.txt +pip-delete-this-directory.txt + +# Unit test / coverage reports +htmlcov/ +.tox/ +.nox/ +.coverage +.coverage.* +.cache +nosetests.xml +coverage.xml +*.cover +*.py,cover +.hypothesis/ +.pytest_cache/ + +# Translations +*.mo +*.pot + +# Django stuff: +*.log +local_settings.py +db.sqlite3 +db.sqlite3-journal + +# Flask stuff: +instance/ +.webassets-cache + +# Scrapy stuff: +.scrapy + +# Sphinx documentation +docs/_build/ + +# PyBuilder +target/ + +# Jupyter Notebook +.ipynb_checkpoints + +# IPython +profile_default/ +ipython_config.py + +# pyenv +.python-version + +# pipenv +# According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control. +# However, in case of collaboration, if having platform-specific dependencies or dependencies +# having no cross-platform support, pipenv may install dependencies that don't work, or not +# install all needed dependencies. +#Pipfile.lock + +# PEP 582; used by e.g. github.com/David-OConnor/pyflow +__pypackages__/ + +# Celery stuff +celerybeat-schedule +celerybeat.pid + +# SageMath parsed files +*.sage.py + +# Environments +.env +.venv +env/ +venv/ +ENV/ +env.bak/ +venv.bak/ + +# Spyder project settings +.spyderproject +.spyproject + +# Rope project settings +.ropeproject + +# mkdocs documentation +/site + +# mypy +.mypy_cache/ +.dmypy.json +dmypy.json + +# Pyre type checker +.pyre/ + +# Custom for this repository +emailproxy.config +versions +launchd +.idea +*.config +*.iml diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..261eeb9 --- /dev/null +++ b/LICENSE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright [yyyy] [name of copyright owner] + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. diff --git a/README.md b/README.md new file mode 100644 index 0000000..126a17b --- /dev/null +++ b/README.md @@ -0,0 +1,267 @@ +# Email OAuth 2.0 Proxy +Transparently add OAuth 2.0 support to IMAP/POP/SMTP client applications, scripts or any other email use-cases that don't support this authentication method. + + +## Motivation and capabilities +Email services that support IMAP, POP and/or SMTP access are increasingly requiring the use of OAuth 2.0 to authenticate connections, but not all clients support this method. +This tool is a local proxy that intercepts the traditional IMAP/POP/SMTP authentication commands and transparently replaces them with the appropriate SASL (X)OAuth 2.0 commands and credentials. +Your email client, app or device can continue to use the `login` or `auth`/`authenticate` options, with no need to make it aware of OAuth's existence. +The proxy works in the background with a menu bar/taskbar helper or as a headless system service, and is compatible with macOS, Windows and Linux. +It can be used with any email provider that supports OAuth 2.0 authentication, including Outlook, Office 365, Hotmail, 21Vianet, Gmail, Google Workspace, Fastmail, Yahoo, Comcast, AOL and many others. + +### Example use-cases +- You need to use an Office 365 email account, but don't get on with Outlook. +The email client you like doesn't support OAuth 2.0, which became mandatory for IMAP/POP [in January 2023](https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-deprecation-in-exchange-online-september/ba-p/3609437) ([September 2024 for personal Hotmail/Outlook accounts](https://support.microsoft.com/en-us/office/modern-authentication-methods-now-needed-to-continue-syncing-outlook-email-in-non-microsoft-email-apps-c5d65390-9676-4763-b41f-d7986499a90d); [April 2026 for O365 SMTP](https://techcommunity.microsoft.com/t5/exchange-team-blog/exchange-online-to-retire-basic-auth-for-client-submission-smtp/ba-p/4114750)). +- You used to use Gmail via IMAP/POP/SMTP with your raw account credentials (i.e., your real password), but cannot do this now that Google has disabled this method, and don't want to use an [App Password](https://support.google.com/accounts/answer/185833) (or cannot enable this option). +- You have an account already set up in an email client, and you need to switch it to OAuth 2.0 authentication. +You can edit the server details, but the client forces you to delete and re-add the account to enable OAuth 2.0, and you don't want to do this. +- You have made your own script or application that sends or receives email, but it doesn't support OAuth 2.0, and you don't want to have to modify it to implement this. +- You use a device or business application that provides functions such as scan to email, email alerts or email to print, but you can't set it up to use the official OAuth 2.0 workarounds from [Microsoft](https://learn.microsoft.com/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365) or [Google](https://support.google.com/a/answer/176600). +- You work with multiple services or applications that use IMAP/POP/SMTP, and you don't want to have to set up OAuth 2.0 independently for each one. + +In all of these cases and more, this proxy can help – just follow the instructions below to get started. +Visit the [Discussions pages](https://github.com/simonrob/email-oauth2-proxy/discussions) for help with any configuration or setup problems, or [open an issue](https://github.com/simonrob/email-oauth2-proxy/issues) to report bugs or make suggestions. +For commercial support or feature requests, please also consider [sponsoring this project](https://github.com/sponsors/simonrob?frequency=one-time). + + +## Getting started +Begin by downloading the proxy via one of the following methods: + +
    +
  1. Pick a pre-built release for your platform (macOS or Windows; no installation needed); or,
    2. +
  2. Install from PyPI: set up using python -m pip install "emailproxy[gui]", download the sample emailproxy.config file, then python -m emailproxy to run; or,
    3. +
  3. Clone or download (and star :-) the GitHub repository, then: python -m pip install -r requirements-core.txt -r requirements-gui.txt to install requirements, and python emailproxy.py to run.
    4. +
+ +Next, edit the sample `emailproxy.config` file to add configuration details for each email server and account that you want to use with the proxy. +[Guidance and example account configurations](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) are provided for Office 365, Gmail and several other providers, though you will need to insert your own client credentials for each one (see the [client credentials documentation](#oauth-20-client-credentials) below for help doing this). +You can remove details from the sample configuration file for services you don't use, or add additional ones for any other OAuth 2.0-authenticated IMAP/POP/SMTP servers you would like to use with the proxy. + +You can now start the proxy: depending on which installation option you chose, either launch the application or use the appropriate run command listed above. +A menu bar/taskbar icon should appear. +If this does not happen, see the [dependencies and setup](#dependencies-and-setup) section for help resolving this. +For additional options, including fully headless deployments and integration with a secrets manager, see the [optional arguments](#optional-arguments-and-configuration) and [advanced configuration](#advanced-configuration) sections. + +Finally, open your email client and configure its server details to match the ones you set in the proxy's configuration file. +The correct server to use with an account is identified using the port number you select in your client – for example, to use the sample Office 365 details, this would be `127.0.0.1` on port `1993` for IMAP, port `1995` for POP and port `1587` for SMTP. +The proxy supports multiple accounts simultaneously, and all accounts associated with the same provider can share the same proxy server. +The local connection in your email client should be configured as unencrypted to allow the proxy to operate, but the connection between the proxy and your email server is always secure (implicit SSL/TLS for IMAP and POP; implicit or explicit (STARTTLS) SSL/TLS for SMTP). +See the [sample configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) for additional documentation about advanced features, including local encryption, account configuration inheritance and support for running in a container. + +The first time your email client makes a request you should see a notification from the proxy about authorising your account. +Click the proxy's menu bar icon, select your account name in the `Authorise account` submenu, and then log in via the popup browser window that appears. +The window will close itself once the process is complete. +See the various [optional arguments](#optional-arguments-and-configuration) for support completing authentication if running without a GUI. + +After successful authentication and authorisation you should have IMAP/POP/SMTP access to your account as normal. +Make sure you keep the proxy running at all times to allow it to authorise your email client's background activity – enable `Start at login` from the proxy's menu, or see the [auto-start instructions](#starting-the-proxy-automatically) about how to configure this in various different setups. + +After your accounts are fully set-up and authorised, no further proxy interaction should be required unless your account needs authorising again. +It will notify you if this is the case. + +### OAuth 2.0 client credentials +As part of the proxy setup process you need to provide an OAuth 2.0 `client_id` and (in many cases) a `client_secret` to allow it to authenticate with email servers on your behalf. + +If you have an existing client ID and secret for a desktop app, you can use these directly in the proxy. +If this is not possible, you can also reuse the client ID and secret from any email client that supports IMAP/POP/SMTP OAuth 2.0 authentication with the email server you would like to connect to (such as [the](https://github.com/mozilla/releases-comm-central/blob/812b7c9068ca5cac0580b0ddbea8e34c141cd441/mailnews/base/src/OAuth2Providers.jsm) [many](https://github.com/mozilla/releases-comm-central/blob/master/mailnews/base/src/OAuth2Providers.sys.mjs) [existing](https://github.com/Foundry376/Mailspring/blob/master/app/internal_packages/onboarding/lib/onboarding-constants.ts) [open](https://gitlab.gnome.org/GNOME/evolution-data-server/-/blob/master/CMakeLists.txt) [source](https://gitlab.gnome.org/GNOME/gnome-online-accounts/-/blob/master/meson_options.txt) [clients](https://github.com/M66B/FairEmail/blob/master/app/src/main/res/xml/providers.xml) with OAuth 2.0 support), but please do this with care and restraint as access through reused tokens will be associated with the token owner rather than your own client. + +If you do not want to use credentials from an existing client you will need to register your own. +The process to do this is different for each provider, but the registration guides for several common ones are linked here. +In all cases, when registering, make sure your client is set up to use an OAuth scope that will give it permission to access IMAP/POP/SMTP as desired. +It is also highly recommended to use a scope that will grant "offline" access (i.e., a way to [refresh the OAuth 2.0 authentication token](https://oauth.net/2/refresh-tokens/) without user intervention). +The [sample configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) provides example scope values for several common providers. + +- Office 365: register a new [Microsoft identity application](https://learn.microsoft.com/entra/identity-platform/quickstart-register-app). +- Gmail / Google Workspace: register a [Google API desktop app client](https://developers.google.com/identity/protocols/oauth2/native-app). +- Outlook / Hotmail (personal accounts): If you are part of the Microsoft 365 Developer Programme or have an Azure account (including free accounts), you can create your own app registration in the Entra admin centre – see [this discussion](https://github.com/simonrob/email-oauth2-proxy/discussions/301) for a guide. +If not, you will need to reuse an existing client ID – see, for example, [this sample configuration](https://github.com/simonrob/email-oauth2-proxy/issues/297#issuecomment-2424200404). +- Fastmail: register a new [Fastmail OAuth client](https://www.fastmail.com/dev/#registration). +- AOL and Yahoo Mail (and subproviders such as AT&T) are not currently allowing new client registrations with the OAuth email scope – the only option here is to reuse the credentials from an existing client that does have this permission. + +The proxy supports [Google Cloud service accounts](https://cloud.google.com/iam/docs/service-account-overview) for access to Google Workspace Gmail. +It also supports the [client credentials grant (CCG)](https://learn.microsoft.com/entra/identity-platform/v2-oauth2-client-creds-grant-flow), [resource owner password credentials grant (ROPCG)](https://learn.microsoft.com/entra/identity-platform/v2-oauth-ropc) and [device authorisation grant (DAG)](https://tools.ietf.org/html/rfc8628) OAuth 2.0 flows, and [certificate credentials (JWT)](https://learn.microsoft.com/entra/identity-platform/certificate-credentials). +Please note that currently only Office 365 / Outlook is known to support the CCG, ROPCG, DAG and certificate credentials methods. +See the [sample configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) for further details. + + +## Optional arguments and configuration +When starting the proxy there are several optional arguments that can be set to customise its behaviour. + +- `--no-gui` will launch the proxy without an icon, which allows it to be run as a `systemctl` service as demonstrated in [this example](https://github.com/simonrob/email-oauth2-proxy/issues/2#issuecomment-839713677), or fully headless as demonstrated in [various](https://github.com/michaelstepner/email-oauth2-proxy-aws) [other](https://github.com/blacktirion/email-oauth2-proxy-docker) subprojects. +Please note that unless you also specify one of the authorisation options below, or are using an OAuth 2.0 flow that does not require user authorisation, this mode is only of use if you have already authorised your accounts through the proxy in GUI mode, or are loading a proxy configuration file that already contains the cached authorisation tokens. +If you do not set `--external-auth` or `--local-server-auth`, accounts that have not yet been authorised (or for whatever reason require re-authorisation) will time out when authenticating, and an error will be printed to the log. + +- `--external-auth` configures the proxy to present an account authorisation URL to be opened in an external browser and wait for you to copy+paste the post-authorisation result. +In GUI mode this can be useful in situations where the proxy's own browser window does not have access to some required authentication attribute of your typical setup. +In no-GUI mode this option allows you to authenticate accounts entirely externally (unlike `--local-server-auth`, which starts a local web server), though you will need to monitor the proxy's output and/or log for authentication notifications. + + After visiting the link provided and authorising account access, paste the final URL from your browser's address bar back into the proxy's popup window (GUI mode) or the terminal (no-GUI mode) to give it access to transparently proxy your login. +You should ignore any browser error message that is shown (e.g., `unable to connect`); the important part is the URL itself. +This argument is identical to enabling external authorisation mode from the `Authorise account` submenu of the proxy's menu bar icon. + +- `--local-server-auth` is similar to `--external-auth`, but instead instructs the proxy to temporarily start an internal web server to receive authentication responses. +The `--external-auth` option is ignored in this mode. +To authorise your account, visit the link that is provided, authenticate, and proceed until you are presented with a success webpage from the proxy. +Please note that while authentication links can actually be visited from anywhere to log in and authorise access, by default the final redirection target (i.e., a link starting with your account's `redirect_uri` value) must be accessed from the machine hosting the proxy itself so that the local server can receive the authorisation result. +See the [sample configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) for advanced options to configure this (via `redirect_listen_address`). + +- `--config-file` allows you to specify the location of a [configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) that the proxy should load. +If this argument is not provided, the proxy will look for `emailproxy.config` in its working directory. +By default, the proxy also saves cached OAuth 2.0 tokens back to this file, so it must be writable. +See the `--cache-store` option if you would rather store configuration and cached values separately. + +- `--cache-store` is used to specify a separate location in which to cache authorised OAuth 2.0 tokens and associated metadata. +The value of this argument can either be the full path to a local file (which must be writable), or an identifier for an external store such as a secrets manager (see the [advanced configuration](#advanced-configuration) section). +If this argument is not provided, credentials will be cached in the current configuration file. + +- `--log-file` allows you to specify the location of a file to send log output to (full path required). +Log files are rotated at 32MB and 10 older log files are kept. +This option overrides the proxy's default behaviour, which varies by platform (see [below](#troubleshooting) for details). + +- `--debug` enables debug mode, printing more verbose output to the log as [discussed below](#troubleshooting). +This argument is identical to enabling debug mode from the proxy's menu bar icon. +If needed, debug mode can also be toggled at runtime by sending the signal `SIGUSR1` (e.g.: `pkill -SIGUSR1 -f emailproxy`). + +### Advanced configuration +The [example configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) contains further documentation for many additional features of the proxy, including catch-all (wildcard) accounts, locally-encrypted connections, advanced OAuth 2.0 flows, integration with a secrets manager and more. + +If you are using the proxy in a non-GUI environment it is possible to skip installation of dependencies that apply only to the interactive version. +To do this, install via `python -m pip install emailproxy` (i.e., without the `[gui]` variant option), and pass the [`--no-gui`](#optional-arguments-and-configuration) argument when starting the proxy. +Please note that the proxy was designed as a GUI-based tool from the outset due to the inherently interactive nature of the most common OAuth 2.0 authorisation flows, and there are limits to its ability to support fully no-GUI operation. +See the [optional arguments and configuration](#optional-arguments-and-configuration) section of this file for further details. + +If your network requires connections to use an existing proxy, you can instruct the script to use this by setting the [proxy handler](https://docs.python.org/3/library/urllib.request.html#urllib.request.ProxyHandler) environment variable `https_proxy` (and/or `http_proxy`) – for example, `https_proxy=localhost python -m emailproxy`. + +After installing its requirements, the proxy script can be packaged as a single self-contained executable using [Nuitka](https://nuitka.net/) (`nuitka --standalone --macos-create-app-bundle emailproxy.py`) or [pyinstaller](https://pyinstaller.org/) (`pyinstaller --onefile emailproxy.py`[[1]](#f1)). +A pyinstaller-packaged version is provided automatically for each [release](https://github.com/simonrob/email-oauth2-proxy/releases). + +Python 3.7 or later is required to run the proxy. +The [python2 branch](https://github.com/simonrob/email-oauth2-proxy/tree/python2) provides minimal compatibility with python 2.7, but with a limited feature set, and no ongoing maintenance. +See [issue 38](https://github.com/simonrob/email-oauth2-proxy/issues/38) for further discussion. + +### Starting the proxy automatically +In order for the proxy to authenticate background requests from your email client it needs to be kept running constantly. +The easiest way to do this is to start the script automatically. +In GUI mode the proxy has basic support for this built-in: click its menu bar icon and then select `Start at login`, which will stop the terminal instance and restart the script, configuring it to run each time you log in. +On macOS, if you are presented with a prompt about file access here, make sure you grant this so that python can run the proxy in the background. +For more advanced configurations, you may want to customise the startup behaviour and edit the script's parameters. +The method to achieve this differs depending on whether you are using macOS, Windows or Linux. + +On macOS, the file `~/Library/LaunchAgents/ac.robinson.email-oauth2-proxy.plist` is used to configure automatic starting of the proxy. +If you stop the proxy's service (i.e., `Quit Email OAuth 2.0 Proxy` from the menu bar), you can restart it using `launchctl start ac.robinson.email-oauth2-proxy` from a terminal. +You can stop, disable or remove the service from your startup items either via the menu bar icon option, or using `launchctl unload `_`[plist path]`_. +If you edit the plist file manually, make sure you `unload` and then `load` it to update the system with your changes. +If the `Start at login` option appears not to be working for you on macOS, see the [known issues section](#known-issues) for potential solutions. + +On Windows the auto-start functionality is achieved via a shortcut in your user account's startup folder. +Pressing `⊞ Win` + `r` and entering `shell:startup` (and then clicking OK) will open this folder – from here you can either double-click the `ac.robinson.email-oauth2-proxy.cmd` file to relaunch the proxy, edit it to configure, or delete this file (either manually or by deselecting the option in the proxy's menu) to remove the proxy from your startup items. + +On Linux this feature assumes that your system supports XDG Autostart. +A Desktop Entry file `ac.robinson.email-oauth2-proxy.desktop` will be created in `~/.config/autostart/`. +Use the proxy's menu option (or manually remove this file) to prevent it starting when you log in. +It is also possible to run the proxy as a service (e.g., via `systemctl`) – see the `--no-gui` mode option above for more details. + + +## Troubleshooting +If you encounter problems using the proxy, enabling `Debug mode` from the menu or passing `--debug` as a command line argument will print all client–proxy–server communication to your system log to help identify the issue. +This will include all commands to and responses from the server (and also as a result the content of your email messages). + +On macOS this can be viewed using Console.app or `log stream --predicate 'subsystem == "ac.robinson.email-oauth2-proxy"' --level=debug`. +On Windows a file `emailproxy.log` will be created in the same location as the proxy (see also the `--log-file` option). +On Linux you can use, for example, `tail -f /var/log/syslog | grep "Email OAuth 2.0 Proxy"`. + +Please note that debug mode may also result in your login credentials being printed to the log (though this is avoided where possible). +However, it is worth pointing out that because account authorisation with the remote email server is handled entirely through OAuth 2.0 in a web browser, while the username you set in your email client must be correct, the password used for the local IMAP/POP/SMTP connection to the proxy can be anything you like, and does not need to be the one you actually use to log in to your account (though it must be the same value each time, or you will be asked to re-authenticate repeatedly by the proxy). +The password you provide via your email client is used only to encrypt and decrypt the OAuth 2.0 authentication token that the proxy transparently sends to the server on your behalf. +Because of this, if you are concerned about debug mode and security you can use a test password for debugging and then replace it with a secure password (and authenticate again) once set up. + +It is often helpful to be able to view the raw connection details when debugging (i.e., without using your email client). +This can be achieved using `telnet`, [PuTTY](https://www.chiark.greenend.org.uk/~sgtatham/putty/) or similar. +For example, to test the Office 365 IMAP server from the [example configuration](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config), first open a connection using `telnet 127.0.0.1 1993`, and then send a login command: `a1 login e@mail.com password`, replacing `e@mail.com` with your email address, and `password` with any value you like during testing (see above for why the password is irrelevant). +If you have already authorised your account with the proxy you should see a response starting with `a1 OK`; if not, this command should trigger a notification from the proxy about authorising your account. +Note that POP and SMTP are different protocols, and while they can be tested in this way, they require different commands to be sent – see [this issue comment](https://github.com/simonrob/email-oauth2-proxy/issues/251#issuecomment-2133976839) for further details. + +If you are using a [secure local connection](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) the interaction with the remote email server is the same as above, but you will need to use a local debugging tool that supports encryption. +The easiest approach here is to use [OpenSSL](https://www.openssl.org/): `openssl s_client -crlf -connect 127.0.0.1:1993`. + +If you are having trouble actually connecting to the proxy, it is always worth double-checking the `local_address` values that you are using. +The [sample configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) sets this parameter to `127.0.0.1` for all servers. +If you remove this value and do not provide your own, the proxy defaults to `::` – in most cases this resolves to `localhost` for both IPv4 and IPv6 configurations, but it is possible that this differs depending on your environment. +If you are unable to connect to the proxy from your email client, first try specifying this value explicitly – see the [sample configuration file](https://github.com/simonrob/email-oauth2-proxy/blob/main/emailproxy.config) for further details about how to do this. +Please try setting and connecting to both IPv4 (i.e., `127.0.0.1`) and IPv6 (i.e., `::1`) loopback addresses before reporting any connection issues with the proxy. + +### Dependencies and setup +On macOS the proxy's setup and installation instructions should automatically bundle or install all required dependencies. +Any error messages you may encounter (for example, with your `pip` version and `cryptography`, or `pillow` and `imagingft` dependencies, or [macOS SSL failures](https://github.com/simonrob/email-oauth2-proxy/issues/14#issuecomment-1077379254)) normally give clear explanations of the issues and point to instructions for resolving these problems. +Please [open an issue](https://github.com/simonrob/email-oauth2-proxy/issues) if you encounter any other problems here. + +When first launching on Linux in GUI mode you may encounter errors similar to `Namespace […] not available`, issues with the task bar icon display, or no browser popup when attempting to authorise your accounts. +This is caused by missing dependencies for [pystray](https://github.com/moses-palmer/pystray/) and [pywebview](https://github.com/r0x0r/pywebview/), which are used to display the menu bar icon and authentication windows. +See the [pywebview dependencies](https://pywebview.flowrl.com/guide/installation.html#dependencies) and [pystray FAQ](https://pystray.readthedocs.io/en/latest/faq.html) pages and [several](https://github.com/simonrob/email-oauth2-proxy/issues/1#issuecomment-831746642) [previous](https://github.com/simonrob/email-oauth2-proxy/issues/136#issuecomment-1430417456) [closed](https://github.com/simonrob/email-oauth2-proxy/issues/305#issuecomment-2482989955) [issues](https://github.com/simonrob/email-oauth2-proxy/issues/342#issuecomment-2775313239) in this repository for a summary and suggestions about how to resolve this. + +A similar issue may occur on Windows with the [pythonnet](https://github.com/pythonnet/pythonnet) package, which is required by [pywebview](https://github.com/r0x0r/pywebview). +The [pythonnet installation instructions](https://github.com/pythonnet/pythonnet/wiki/Installation) may offer alternative ways to install this package if the default installation fails. +Note that the public releases of pythonnet can take some time to be compatible with the latest major python release, so it can be worth using a slightly older version of python, or a pre-release version of pythonnet. + +### Known issues +- With some combinations of operating systems, web engines and virtual environments, keyboard control or input to the proxy's popup authorisation window may not always work. +On Windows this is normally limited to keyboard shortcuts (i.e., copy/paste), but in some virtual environments on macOS the entire keyboard may not work. +As a workaround, the proxy will enable pywebview's debug mode when you run the proxy itself in debug mode, which should allow you to use the right-click context menu to copy/paste to enter text. +If you are unable to proceed with popup-based authentication even with this workaround, it is worth trying the proxy's `--external-auth` or `--local-server-auth` options. + +- If the authorisation window fails to render due to an issue with hardware acceleration (for example: `MESA: error: ZINK: failed to choose pdev`), you can try disabling hardware rendering by setting the environment variable `LIBGL_ALWAYS_SOFTWARE=1`. +You may also wish to try disabling the DMABUF renderer in WebKit with `WEBKIT_DISABLE_DMABUF_RENDERER=1`. + +- On macOS (10.14 and later), you may find that when first running the proxy as a service you need to manually load its launch agent in order to trigger a file access permission prompt. +You will know intervention is necessary if the proxy exits (rather than restarts) the first time you click `Start at login` from its menu bar icon. +To resolve this, exit the proxy and then run `launchctl load ~/Library/LaunchAgents/ac.robinson.email-oauth2-proxy.plist` from a terminal. +A permission pop-up should appear requesting file access for python. +Once this has been approved, the proxy's menu bar icon will appear as normal. +In some cases — particularly when running the proxy in a virtual environment, or using the built-in macOS python, rather than the python.org version, or installations managed by, e.g., homebrew, pyenv, etc. — the permission prompt does not appear. +If this happens it is worth first trying to `unload` and then `load` the service via `launchctl`. +If this still does not cause the prompt to appear, the only currently-known resolution is to run the proxy outside of a virtual environment and manually grant Full Disk Access to your python executable via the privacy settings in the macOS System Preferences. +You may also need to edit the proxy's launch agent plist file, which is found at the location given [in the command above](#starting-the-proxy-automatically), to set the path to your python executable – it must be the real path rather than a symlink (the `readlink` command can help here). +Fortunately this is a one-time fix, and once the proxy loads successfully via this method you will not need to adjust its startup configuration again (except perhaps when upgrading to a newer major macOS version, in which case just repeat the procedure). + +### Other problems +Please feel free to [open an issue](https://github.com/simonrob/email-oauth2-proxy/issues) reporting any bugs you find, or [submit a pull request](https://github.com/simonrob/email-oauth2-proxy/pulls) to help improve this tool. + + +## Advanced features +The [plugins variant of the proxy](https://github.com/simonrob/email-oauth2-proxy/tree/plugins) has an additional feature that enables the use of separate scripts to modify IMAP/POP/SMTP commands when they are received from the client or server before passing through to the other side of the connection. +This allows a wide range of additional capabilities or triggers to be added the proxy. + +For example, the [IMAPIgnoreSentMessageUpload plugin](https://github.com/simonrob/email-oauth2-proxy/blob/plugins/plugins/IMAPIgnoreSentMessageUpload.py) intercepts any client commands to add emails to the IMAP sent messages mailbox, which resolves message duplication issues for servers that automatically do this when emails are received via SMTP (e.g., Office 365, Gmail, etc.). +The [IMAPCleanO365ATPLinks plugin](https://github.com/simonrob/email-oauth2-proxy/blob/plugins/plugins/IMAPCleanO365ATPLinks.py) restores "Safe Links" modified by Microsoft Defender for Office 365 to their original URLs, while the [IMAPRegexContentReplacer plugin](https://github.com/simonrob/email-oauth2-proxy/blob/plugins/plugins/IMAPRegexContentReplacer.py) lets you match and remove/replace any content in the message. +The [SMTPBlackHole plugin](https://github.com/simonrob/email-oauth2-proxy/blob/plugins/plugins/SMTPBlackHole.py) gives the impression emails are being sent but actually silently discards them, which is useful for testing email sending tools. + +See the [documentation and examples](https://github.com/simonrob/email-oauth2-proxy/tree/plugins/plugins) for further details, additional sample plugins and setup instructions. + + +## Potential improvements (pull requests welcome) +- Full feature parity on different platforms (e.g., live menu updating; monitoring network status; clickable notifications) +- Switch to asyncio? (with Python 3.12, [PEP 594](https://peps.python.org/pep-0594/) removed the asyncore package that the proxy is built upon – currently mitigated by the use of [pyasyncore](https://pypi.org/project/pyasyncore/)) +- Local and/or remote STARTTLS for IMAP/POP? + + +## Related projects and alternatives +Michael Stepner has created a [Terraform configuration](https://github.com/michaelstepner/email-oauth2-proxy-aws) that helps run this proxy on a lightweight cloud server (AWS EC2). +Thiago Macieira has provided a [makefile and systemd configuration files](https://github.com/thiagomacieira/email-oauth2-proxy/tree/Add_a_Makefile_and_systemd_configuration_files_to_install_system_wide). +For Docker, Moriah Morgan has an [example configuration](https://github.com/blacktirion/email-oauth2-proxy-docker). +For Helm, Patrick Joyce has an [example chart](https://github.com/pjaudiomv/email-oauth2-proxy-helm). + +If you already use postfix, the [sasl-xoauth2](https://github.com/tarickb/sasl-xoauth2) plugin is probably a better solution than running this proxy. +Similarly, if you use an application that is able to handle OAuth 2.0 tokens but just cannot retrieve them itself, then [pizauth](https://github.com/ltratt/pizauth), [mailctl](https://github.com/pdobsan/mailctl) or [oauth-helper-office-365](https://github.com/ahrex/oauth-helper-office-365) may be more appropriate. +There are also dedicated helpers available for specific applications (e.g., [mutt_oauth2](https://gitlab.com/muttmua/mutt/-/blob/master/contrib/mutt_oauth2.py)), and several open-source email clients that support OAuth 2.0 natively (e.g., [Thunderbird](https://www.thunderbird.net/), [Mailspring](https://getmailspring.com/), [FairEmail](https://email.faircode.eu/), [Evolution](https://wiki.gnome.org/Apps/Evolution), etc.). + +[DavMail](http://davmail.sourceforge.net/) is an alternative to this proxy that takes the same approach of providing a local IMAP/POP/SMTP server (and more) for Exchange/Office 365, though it does this by translating these protocols into Exchange API calls rather than proxying the connection. +That approach is very useful in situations where server-side IMAP/POP/SMTP is not supported or enabled, or the full Exchange capabilities are needed, but it has limitations in terms of speed and the number of email messages that can be retrieved. +This proxy was developed to work around these limitations for providers that do support IMAP/POP/SMTP natively. + + +## License +[Apache 2.0](https://github.com/simonrob/email-oauth2-proxy/blob/main/LICENSE) + + +--- +1. If you are packaging the GUI version of the proxy using pyinstaller, you may need to add `--hidden-import timeago.locales.en_short` until [this `timeago` issue](https://github.com/hustcc/timeago/issues/40) is resolved. diff --git a/SECURITY.md b/SECURITY.md new file mode 100644 index 0000000..0ae612b --- /dev/null +++ b/SECURITY.md @@ -0,0 +1,10 @@ +# Security Policy + +## Supported Versions + +Using the [latest release of the proxy](https://github.com/simonrob/email-oauth2-proxy/releases/latest) is always recommended. +Any security issues found in prior versions should be reported, but may only be fixed if they affect the latest version. + +## Reporting a Vulnerability + +Report vulnerabilities or security issues using [GitHub's security tools](https://github.com/simonrob/email-oauth2-proxy/security). diff --git a/emailproxy.py b/emailproxy.py new file mode 100644 index 0000000..279f63d --- /dev/null +++ b/emailproxy.py @@ -0,0 +1,3656 @@ +#!/usr/bin/env python3 + +"""A simple IMAP/POP/SMTP proxy that intercepts authenticate and login commands, transparently replacing them with OAuth +2.0 authentication. Designed for apps/clients that don't support OAuth 2.0 but need to connect to modern servers.""" + +__author__ = 'Simon Robinson' +__copyright__ = 'Copyright (c) 2025 Simon Robinson' +__license__ = 'Apache 2.0' +__package_version__ = '2025.10.14' # for pyproject.toml usage only - needs to be ast.literal_eval() compatible +__version__ = '-'.join('%02d' % int(part) for part in __package_version__.split('.')) # ISO 8601 (YYYY-MM-DD) + +import abc +import argparse +import base64 +import binascii +import configparser +import contextlib +import datetime +import enum +import errno +import hashlib +import io +import ipaddress +import json +import logging +import logging.handlers +import os +import pathlib +import platform +import plistlib +import queue +import re +import secrets +import select +import signal +import socket +import ssl +import subprocess +import sys +import threading +import time +import urllib.error +import urllib.parse +import urllib.request +import warnings +import wsgiref.simple_server +import wsgiref.util +import zlib + +# asyncore is essential, but has been deprecated and will be removed in python 3.12 (see PEP 594) +# pyasyncore is our workaround, so suppress this warning until the proxy is rewritten in, e.g., asyncio +with warnings.catch_warnings(): + warnings.simplefilter('ignore', DeprecationWarning) + import asyncore + +# for encrypting/decrypting the locally-stored credentials +from cryptography.fernet import Fernet, MultiFernet, InvalidToken +from cryptography.hazmat.backends import default_backend +from cryptography.hazmat.primitives import hashes +from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC + +# by default the proxy is a GUI application with a menu bar/taskbar icon, but it is also useful in 'headless' contexts +# where not having to install GUI-only requirements can be helpful - see the proxy's readme (the `--no-gui` option) +MISSING_GUI_REQUIREMENTS = [] + +no_gui_parser = argparse.ArgumentParser(add_help=False) +no_gui_parser.add_argument('--no-gui', action='store_false', dest='gui') +no_gui_args = no_gui_parser.parse_known_args()[0] +if no_gui_args.gui: + try: + # noinspection PyUnresolvedReferences + import pystray # the menu bar/taskbar GUI + except Exception as gui_requirement_import_error: # see #204 - incomplete pystray installation can throw exceptions + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + no_gui_args.gui = False # we need the dummy implementation + +if not no_gui_args.gui: + class DummyPystray: # dummy implementation allows initialisation to complete (with skeleton to avoid lint warnings) + class Icon: + def __init__(self, *args, **kwargs): + pass + + def run(self, *args, **kwargs): + pass + + class Menu: + SEPARATOR = None + + def __init__(self, *args, **kwargs): + pass + + class MenuItem: + def __init__(self, *args, **kwargs): + pass + + + pystray = DummyPystray # this is just to avoid unignorable IntelliJ warnings about naming and spacing +del no_gui_parser +del no_gui_args + +try: + # noinspection PyUnresolvedReferences + from PIL import Image, ImageDraw, ImageFont # draw the menu bar icon from the TTF font stored in APP_ICON +except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + +try: + # noinspection PyUnresolvedReferences + import timeago # the last authenticated activity hint +except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + +try: + # noinspection PyUnresolvedReferences + import webview # the popup authentication window (in default and GUI `--external-auth` modes only) +except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + +try: + # pylint: disable-next=ungrouped-imports + import importlib.metadata as importlib_metadata # get package version numbers - available in stdlib from python 3.8 +except ImportError: + try: + # noinspection PyUnresolvedReferences + import importlib_metadata + except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + +try: + # noinspection PyUnresolvedReferences + import packaging.version # parse package version numbers - used to work around various GUI-only package issues +except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + +# for macOS-specific functionality +if sys.platform == 'darwin': + try: + # PyUnresolvedReferences; see: youtrack.jetbrains.com/issue/PY-11963 (same for others with this suppression) + # noinspection PyPackageRequirements,PyUnresolvedReferences + import PyObjCTools.MachSignals # SIGTERM handling (only needed in GUI mode; `signal` is sufficient otherwise) + except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + + try: + # noinspection PyPackageRequirements,PyUnresolvedReferences + import SystemConfiguration # network availability monitoring + except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + + try: + # noinspection PyPackageRequirements + import AppKit # retina icon, menu update on click, native notifications and receiving system events + except ImportError as gui_requirement_import_error: + MISSING_GUI_REQUIREMENTS.append(gui_requirement_import_error) + + + class AppKit: # dummy implementation allows initialisation to complete + class NSObject: + pass + +APP_NAME = 'Email OAuth 2.0 Proxy' +APP_SHORT_NAME = 'emailproxy' +APP_PACKAGE = 'ac.robinson.email-oauth2-proxy' + +# noinspection SpellCheckingInspection +APP_ICON = b'''eNp1Uc9rE0EUfjM7u1nyq0m72aQxpnbTbFq0TbJNNkGkNpVKb2mxtgjWsqRJU+jaQHOoeMlVeoiCHqQXrwX/gEK9efGgNy+C4MWbHjxER + DCJb3dTUdQH733zvW/ezHszQADAAy3gIFO+kdbW3lXWAUgRs2sV02igdoL8MfLctrHf6PeBAXBe5OL27r2acry6hPprdLleNbbiXfkUtRfoeh0T4gaju + O6gT9TN5gEWo5GHGNjuXsVAPET+yuKmcdAAETaRR5BfuGuYVRCs/fQjBqGxt98En80/WzpYvaN3tPsvN4eufAWPc/r707dvLPyg/PiCcMSAq1n9AgXHs + MbeedvZz+zMH0YGZ99x7v9LxwyzpuBBpA8oTg9tB8kn0IiIHQLPwT9tuba4BfNQhervPZzdMGBWp1a9hJHYyHBeS2Y2r+I/2LF/9Ku3Q7tXZ9ogJKEEN + +EWbODRqpoaFwRXUJbDvK4Xghlek+WQ5KfKDM3N0dlshiQEQVHzuYJeKMxRVMNhWRISClYmc6qaUPxUitNZTdfz2QyfcmXIOK8xoOZKt7ViUkRqYXekW + J6Sp0urC5fCken5STr0KDoUlyhjVd4nxSUvq3tCftEn8r2ro+mxUDIaCMQmQrGZGHmi53tAT3rPGH1e3qF0p9w7LtcohwuyvnRxWZ8sZUej6WvlhXSk1 + 7k+POJ1iR73N/+w2xN0f4+GJcHtfqoWzgfi6cuZscC54lSq3SbN1tmzC4MXtcwN/zOC78r9BIfNc3M=''' # TTF ('e') -> zlib -> base64 + +CENSOR_CREDENTIALS = True +CENSOR_MESSAGE = b'[[ Credentials removed from proxy log ]]' # replaces actual credentials; must be a byte-type string + +FROZEN_PACKAGE = getattr(sys, 'frozen', False) or '__compiled__' in globals() # for pyinstaller/nuitka etc +script_path = sys.executable if FROZEN_PACKAGE else os.path.realpath(__file__) +if sys.platform == 'darwin' and '.app/Contents/MacOS/' in script_path: # pyinstaller .app binary is within the bundle + if float('.'.join(platform.mac_ver()[0].split('.')[:2])) >= 10.12: # need a known path (due to App Translocation) + script_path = pathlib.Path('~/.%s/%s' % (APP_SHORT_NAME, APP_SHORT_NAME)).expanduser() + else: + script_path = '.'.join(script_path.split('Contents/MacOS/')[0].split('/')[:-1]) +script_path = os.getcwd() if __package__ is not None else os.path.dirname(script_path) # for packaged version (PyPI) +CONFIG_FILE_PATH = CACHE_STORE = os.path.join(script_path, '%s.config' % APP_SHORT_NAME) +CONFIG_SERVER_MATCHER = re.compile(r'^(?P(IMAP|POP|SMTP))-(?P\d+)$') +del script_path + +MAX_CONNECTIONS = 0 # maximum concurrent IMAP/POP/SMTP connections; 0 = no limit; limit is per server + +RECEIVE_BUFFER_SIZE = 65536 # number of bytes to try to read from the socket at a time (limit is per socket) + +MAX_SSL_HANDSHAKE_ATTEMPTS = 1024 # number of attempts before aborting SSL/TLS handshake (max 10ms each); 0 = no limit + +# IMAP/POP/SMTP require \r\n as a line terminator (we use lines only pre-authentication; afterwards just pass through) +LINE_TERMINATOR = b'\r\n' +LINE_TERMINATOR_LENGTH = len(LINE_TERMINATOR) + +# seconds to wait before cancelling authentication requests (i.e., the user has this long to log in) - note that the +# actual server timeout is often around 60 seconds, so the connection may be closed in the background and immediately +# disconnect after login completes; however, the login credentials will still be saved and used for future requests +AUTHENTICATION_TIMEOUT = 600 + +TOKEN_EXPIRY_MARGIN = 600 # seconds before its expiry to refresh the OAuth 2.0 token +TOKEN_LIFETIME = 3600 # seconds to add to the current time to use as a token expiration value where not provided +JWT_LIFETIME = 300 # seconds to add to the current time and use for the `exp` value in JWT certificate credentials + +LOG_FILE_MAX_SIZE = 32 * 1024 * 1024 # when using a log file, its maximum size in bytes before rollover (0 = no limit) +LOG_FILE_MAX_BACKUPS = 10 # the number of log files to keep when LOG_FILE_MAX_SIZE is exceeded (0 = disable rollover) + +IMAP_TAG_PATTERN = r'[!#$&\',-\[\]-z|}~]+' # https://ietf.org/rfc/rfc9051.html#name-formal-syntax +IMAP_AUTHENTICATION_REQUEST_MATCHER = re.compile('^(?P%s) (?P(LOGIN|AUTHENTICATE)) ' + '(?P.*)$' % IMAP_TAG_PATTERN, flags=re.IGNORECASE) +IMAP_LITERAL_MATCHER = re.compile(r'^{(?P\d+)(?P\+?)}$') +IMAP_CAPABILITY_MATCHER = re.compile(r'^\* (?:OK \[)?CAPABILITY .*$', flags=re.IGNORECASE) # note: '* ' *and* '* OK [' + +REQUEST_QUEUE = queue.Queue() # requests for authentication +RESPONSE_QUEUE = queue.Queue() # responses from user +QUEUE_SENTINEL = object() # object to send to signify queues should exit loops +MENU_UPDATE = object() # object to send to trigger a force-refresh of the GUI menu (new catch-all account added) + +PLIST_FILE_PATH = pathlib.Path('~/Library/LaunchAgents/%s.plist' % APP_PACKAGE).expanduser() # launchctl file location +CMD_FILE_PATH = pathlib.Path('~/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup/%s.cmd' % + APP_PACKAGE).expanduser() # Windows startup .cmd file location +AUTOSTART_FILE_PATH = pathlib.Path('~/.config/autostart/%s.desktop' % APP_PACKAGE).expanduser() # XDG Autostart file + +# noinspection SpellCheckingInspection +SECURE_SERVER_ICON = '''iVBORw0KGgoAAAANSUhEUgAAABYAAAAWCAYAAADEtGw7AAAApElEQVR4Ae3VsQ2DMBBA0ZQs4NIreA03GSbyAl6DAbyN+xvh + Ovp0yY9EkQZ8XELHSa+x0S9OAm75cT+F+UFm+vhbmClQLCtF+SnMNAji11lcz5orzCQopo21KJIn3FB37iuaJ9yRd+4zuicsSINViSesyEgbMtQcZgIE + TyNBsIQrXgdVS3h2hGdf+Apf4eIIF+ub16FYBhQd4ci3IiAOBP8/z+kNGUS6hBN6UlIAAAAASUVORK5CYII=''' # 22px SF Symbols lock.fill + +EXTERNAL_AUTH_HTML_BASE = ''' +

Login authorisation request for %s

+

Click the following link to open your browser and approve the request:

+

%s + ⧉

''' + +EXTERNAL_AUTH_HTML = EXTERNAL_AUTH_HTML_BASE + '''

After logging in and successfully + authorising your account, paste and submit the resulting URL from the browser's address bar using the box at the + bottom of this page to allow the %s script to transparently handle login requests on your behalf in future.

+

Note that your browser may show a navigation error (e.g., “localhost refused to connect”) after + successfully logging in, but the final URL is the only important part, and as long as this begins with the + correct redirection URI and contains a valid authorisation code your email client's request will succeed.''' + ( + ' If you are using Windows, submitting can take a few seconds.' if sys.platform == 'win32' else '') + '''

+

According to your proxy configuration file, the expected URL will be of the form:

+ 

%s […] code=[code] […]

+
+
''' + +EXTERNAL_AUTH_DAG_HTML = EXTERNAL_AUTH_HTML_BASE + '''

Enter the following code when + prompted:

%s
⧉ +

You can close this window once authorisation is complete.

''' + +EXITING = False # used to check whether to restart failed threads - is set to True if the user has requested to exit + + +class Log: + """Simple logging to syslog/Console.app on Linux/macOS and to a local file on Windows""" + + _LOGGER = None + _HANDLER = None + _DATE_FORMAT = '%Y-%m-%d %H:%M:%S:' + _SYSLOG_MESSAGE_FORMAT = '%s: %%(message)s' % APP_NAME + _MACOS_USE_SYSLOG = False + + @staticmethod + def initialise(log_file=None): + Log._LOGGER = logging.getLogger(APP_NAME) + if log_file or sys.platform == 'win32': + handler = logging.handlers.RotatingFileHandler( + log_file or os.path.join(os.getcwd() if __package__ is not None else + os.path.dirname(sys.executable if FROZEN_PACKAGE else + os.path.realpath(__file__)), '%s.log' % APP_SHORT_NAME), + maxBytes=LOG_FILE_MAX_SIZE, backupCount=LOG_FILE_MAX_BACKUPS) + handler.setFormatter(logging.Formatter('%(asctime)s: %(message)s')) + + elif sys.platform == 'darwin': + # noinspection PyPackageRequirements + import pyoslog # for macOS-specific unified logging + Log._MACOS_USE_SYSLOG = not pyoslog.is_supported() + if Log._MACOS_USE_SYSLOG: # syslog prior to 10.12 + handler = logging.handlers.SysLogHandler(address='/var/run/syslog') + handler.setFormatter(logging.Formatter(Log._SYSLOG_MESSAGE_FORMAT)) + else: # unified logging in 10.12+ + handler = pyoslog.Handler() + handler.setSubsystem(APP_PACKAGE) + + else: + if os.path.exists('/dev/log'): + handler = logging.handlers.SysLogHandler(address='/dev/log') + handler.setFormatter(logging.Formatter(Log._SYSLOG_MESSAGE_FORMAT)) + else: + handler = logging.StreamHandler() + + Log._HANDLER = handler + Log._LOGGER.addHandler(Log._HANDLER) + Log.set_level(logging.INFO) + + @staticmethod + def get_level(): + return Log._LOGGER.getEffectiveLevel() + + @staticmethod + def set_level(level): + # set both handler and logger level as we just want a direct mapping input->output + Log._HANDLER.setLevel(level) + Log._LOGGER.setLevel(level) + + @staticmethod + def _log(level_method, level, *args): + message = ' '.join(map(str, args)) + if Log.get_level() <= level: + print(datetime.datetime.now().strftime(Log._DATE_FORMAT), message) + + if len(message) > 2048 and (sys.platform not in ['win32', 'darwin'] or Log._MACOS_USE_SYSLOG): + truncation_message = ' [ NOTE: message over syslog length limit truncated to 2048 characters; run `%s' \ + ' --debug` in a terminal to see the full output ] ' % os.path.basename(__file__) + message = message[0:2048 - len(Log._SYSLOG_MESSAGE_FORMAT) - len(truncation_message)] + truncation_message + + # note: need LOG_ALERT (i.e., warning) or higher to show in syslog on macOS + severity = Log._LOGGER.warning if Log._MACOS_USE_SYSLOG else level_method + severity(message) + + @staticmethod + def debug(*args): + Log._log(Log._LOGGER.debug, logging.DEBUG, *args) + + @staticmethod + def info(*args): + Log._log(Log._LOGGER.info, logging.INFO, *args) + + @staticmethod + def error(*args): + Log._log(Log._LOGGER.error, logging.ERROR, *args) + + @staticmethod + def error_string(error): + return getattr(error, 'message', repr(error)) + + @staticmethod + def format_host_port(address): + host, port, *_ = address + with contextlib.suppress(ValueError): + ip = ipaddress.ip_address(host) + host = '[%s]' % host if isinstance(ip, ipaddress.IPv6Address) else host + return '%s:%d' % (host, port) + + @staticmethod + def get_last_error(): + error_type, value, _traceback = sys.exc_info() + del _traceback # used to be required in python 2; may no-longer be needed, but best to be safe + return error_type, value # note that if no exception has currently been raised, this will return `None, None` + + +class CacheStore(abc.ABC): + """Override this class to provide additional cache store options for a dictionary of OAuth 2.0 credentials, then add + an entry in AppConfig's `_EXTERNAL_CACHE_STORES` to make them available via the proxy's `--cache-store` parameter""" + + @staticmethod + @abc.abstractmethod + def load(store_id): + return {} + + @staticmethod + @abc.abstractmethod + def save(store_id, config_dict): + pass + + +class AWSSecretsManagerCacheStore(CacheStore): + # noinspection PyUnresolvedReferences + @staticmethod + def _get_boto3_client(store_id): + try: + # noinspection PyGlobalUndefined + global boto3, botocore + import boto3 + import botocore.exceptions + except ModuleNotFoundError: + Log.error('Unable to load AWS SDK - please install the `boto3` module: `python -m pip install boto3`') + return None, None + + # allow a profile to be chosen by prefixing the store_id - the separator used (`||`) will not be in an ARN + # or secret name (see: https://docs.aws.amazon.com/secretsmanager/latest/apireference/API_CreateSecret.html) + split_id = store_id.split('||', maxsplit=1) + if '||' in store_id: + return split_id[1], boto3.session.Session(profile_name=split_id[0]).client('secretsmanager') + return store_id, boto3.client(service_name='secretsmanager') + + @staticmethod + def _create_secret(aws_client, store_id): + if store_id.startswith('arn:'): + Log.info('Creating new AWS Secret "%s" failed - it is not possible to choose specific ARNs for new secrets') + return False + + try: + aws_client.create_secret(Name=store_id, ForceOverwriteReplicaSecret=False) + Log.info('Created new AWS Secret "%s"' % store_id) + return True + + except botocore.exceptions.ClientError as e: + if e.response['Error']['Code'] == 'AccessDeniedException': + AWSSecretsManagerCacheStore._log_error( + 'Creating new AWS Secret "%s" failed - access denied: does the IAM user have the ' + '`secretsmanager:CreateSecret` permission?' % store_id, e) + else: + AWSSecretsManagerCacheStore._log_error('Creating new AWS Secret "%s" failed with an unexpected error; ' + 'see the proxy\'s debug log' % store_id, e) + return False + + @staticmethod + def _log_error(error_message, debug_error): + Log.debug('AWS %s: %s' % (debug_error.response['Error']['Code'], debug_error.response['Error']['Message'])) + Log.error(error_message) + + @staticmethod + def load(store_id): + store_id, aws_client = AWSSecretsManagerCacheStore._get_boto3_client(store_id) + if aws_client: + try: + Log.debug('Requesting credential cache from AWS Secret "%s"' % store_id) + retrieved_secrets = json.loads(aws_client.get_secret_value(SecretId=store_id)['SecretString']) + Log.info('Fetched', len(retrieved_secrets), 'cached account entries from AWS Secret "%s"' % store_id) + return retrieved_secrets + + except botocore.exceptions.ClientError as e: + error_code = e.response['Error']['Code'] + if error_code == 'ResourceNotFoundException': + Log.info('AWS Secret "%s" does not exist - attempting to create it' % store_id) + AWSSecretsManagerCacheStore._create_secret(aws_client, store_id) + elif error_code == 'AccessDeniedException': + AWSSecretsManagerCacheStore._log_error( + 'Fetching AWS Secret "%s" failed - access denied: does the IAM user have the ' + '`secretsmanager:GetSecretValue` permission?' % store_id, e) + else: + AWSSecretsManagerCacheStore._log_error( + 'Fetching AWS Secret "%s" failed - unexpected error; see the proxy debug log' % store_id, e) + else: + Log.error('Unable to get AWS SDK client; cannot fetch credentials from AWS Secrets Manager') + return {} + + @staticmethod + def save(store_id, config_dict, create_secret=True): + store_id, aws_client = AWSSecretsManagerCacheStore._get_boto3_client(store_id) + if aws_client: + try: + Log.debug('Saving credential cache to AWS Secret "%s"' % store_id) + aws_client.put_secret_value(SecretId=store_id, SecretString=json.dumps(config_dict)) + Log.info('Cached', len(config_dict), 'account entries to AWS Secret "%s"' % store_id) + + except botocore.exceptions.ClientError as e: + error_code = e.response['Error']['Code'] + if error_code == 'ResourceNotFoundException' and create_secret: + Log.info('AWS Secret "%s" does not exist - attempting to create it' % store_id) + if AWSSecretsManagerCacheStore._create_secret(aws_client, store_id): + AWSSecretsManagerCacheStore.save(store_id, config_dict, create_secret=False) + elif error_code == 'AccessDeniedException': + AWSSecretsManagerCacheStore._log_error( + 'Caching to AWS Secret "%s" failed - access denied: does the IAM user have the ' + '`secretsmanager:PutSecretValue` permission?' % store_id, e) + else: + AWSSecretsManagerCacheStore._log_error( + 'Caching to AWS Secret "%s" failed - unexpected error; see the proxy debug log' % store_id, e) + else: + Log.error('Unable to get AWS SDK client; cannot cache credentials to AWS Secrets Manager') + + +class ConcurrentConfigParser: + """Helper wrapper to add locking to a ConfigParser object (note: only wraps the methods used in this script)""" + + def __init__(self): + self.config = configparser.ConfigParser(interpolation=None) + self.lock = threading.Lock() + + def read(self, filename): + with self.lock: + self.config.read(filename) + + def sections(self): + with self.lock: + return self.config.sections() + + def add_section(self, section): + with self.lock: + self.config.add_section(section) + + def get(self, section, option, fallback=None): + with self.lock: + return self.config.get(section, option, fallback=fallback) + + def getint(self, section, option, fallback=None): + with self.lock: + return self.config.getint(section, option, fallback=fallback) + + def getboolean(self, section, option, fallback=None): + with self.lock: + return self.config.getboolean(section, option, fallback=fallback) + + def set(self, section, option, value): + with self.lock: + self.config.set(section, option, value) + + def remove_option(self, section, option): + with self.lock: + self.config.remove_option(section, option) + + def write(self, file): + with self.lock: + self.config.write(file) + + def items(self): + with self.lock: + return self.config.items() # used in read_dict when saving to cache store + + +class AppConfig: + """Helper wrapper around ConfigParser to cache servers/accounts, and avoid writing to the file until necessary""" + + _PARSER = None + _PARSER_LOCK = threading.Lock() + + # note: removing the unencrypted version of `client_secret_encrypted` is not automatic with --cache-store (see docs) + _CACHED_OPTION_KEYS = ['access_token', 'access_token_expiry', 'refresh_token', 'token_salt', 'token_iterations', + 'client_secret_encrypted', 'last_activity'] + + # additional cache stores may be implemented by extending CacheStore and adding a prefix entry in this dict + _EXTERNAL_CACHE_STORES = {'aws:': AWSSecretsManagerCacheStore} + + @staticmethod + def _load(): + config_parser = ConcurrentConfigParser() + config_parser.read(CONFIG_FILE_PATH) + + # cached account credentials can be stored in the configuration file (default) or, via `--cache-store`, a + # separate local file or external service (such as a secrets manager) - we combine these sources at load time + if CACHE_STORE != CONFIG_FILE_PATH: + # it would be cleaner to avoid specific options here, but best to load unexpected sections only when enabled + allow_catch_all_accounts = config_parser.getboolean(APP_SHORT_NAME, 'allow_catch_all_accounts', + fallback=False) + + cache_file_parser = AppConfig._load_cache(CACHE_STORE) + cache_file_accounts = [s for s in cache_file_parser.sections() if '@' in s] + for account in cache_file_accounts: + if allow_catch_all_accounts and account not in config_parser.sections(): # missing sub-accounts + config_parser.add_section(account) + for option in cache_file_parser.options(account): + if option in AppConfig._CACHED_OPTION_KEYS: + config_parser.set(account, option, cache_file_parser.get(account, option)) + + return config_parser + + @staticmethod + def _load_cache(cache_store_identifier): + cache_file_parser = configparser.ConfigParser(interpolation=None) + for prefix, cache_store_handler in AppConfig._EXTERNAL_CACHE_STORES.items(): + if cache_store_identifier.startswith(prefix): + cache_file_parser.read_dict(cache_store_handler.load(cache_store_identifier[len(prefix):])) + return cache_file_parser + cache_file_parser.read(cache_store_identifier) # default cache is a local file (does not error if non-existent) + return cache_file_parser + + @staticmethod + def get(): + with AppConfig._PARSER_LOCK: + if AppConfig._PARSER is None: + AppConfig._PARSER = AppConfig._load() + return AppConfig._PARSER + + @staticmethod + def unload(): + with AppConfig._PARSER_LOCK: + AppConfig._PARSER = None + + @staticmethod + def get_global(name, fallback): + return AppConfig.get().getboolean(APP_SHORT_NAME, name, fallback) + + @staticmethod + def servers(): + return [s for s in AppConfig.get().sections() if CONFIG_SERVER_MATCHER.match(s)] + + @staticmethod + def accounts(): + return [s for s in AppConfig.get().sections() if '@' in s] + + @staticmethod + def get_option_with_catch_all_fallback(config, account, option, fallback=None): + if AppConfig.get_global('allow_catch_all_accounts', fallback=False): + user_domain = '@%s' % account.split('@')[-1] + fallback = config.get(user_domain, option, fallback=config.get('@', option, fallback=fallback)) + return config.get(account, option, fallback=fallback) + + @staticmethod + def save(): + with AppConfig._PARSER_LOCK: + if AppConfig._PARSER is None: # intentionally using _PARSER not get() so we don't (re-)load if unloaded + return + + if CACHE_STORE != CONFIG_FILE_PATH: + # in `--cache-store` mode we ignore everything except _CACHED_OPTION_KEYS (OAuth 2.0 tokens, etc.) + output_config_parser = configparser.ConfigParser(interpolation=None) + output_config_parser.read_dict(AppConfig._PARSER) # a deep copy of the current configuration + config_accounts = [s for s in output_config_parser.sections() if '@' in s] + + for account in config_accounts: + for option in output_config_parser.options(account): + if option not in AppConfig._CACHED_OPTION_KEYS: + output_config_parser.remove_option(account, option) + + for section in output_config_parser.sections(): + if section not in config_accounts or len(output_config_parser.options(section)) <= 0: + output_config_parser.remove_section(section) + + AppConfig._save_cache(CACHE_STORE, output_config_parser) + + else: + # by default we cache to the local configuration file, and rewrite all values each time + try: + with open(CONFIG_FILE_PATH, mode='w', encoding='utf-8') as config_output: + AppConfig._PARSER.write(config_output) + except IOError: + Log.error('Error saving state to config file at', CONFIG_FILE_PATH, '- is the file writable?') + + @staticmethod + def _save_cache(cache_store_identifier, output_config_parser): + for prefix, cache_store_handler in AppConfig._EXTERNAL_CACHE_STORES.items(): + if cache_store_identifier.startswith(prefix): + cache_store_handler.save(cache_store_identifier[len(prefix):], + {account: dict(output_config_parser.items(account)) for account in + output_config_parser.sections()}) + return + try: + with open(cache_store_identifier, mode='w', encoding='utf-8') as config_output: + output_config_parser.write(config_output) + except IOError: + Log.error('Error saving state to cache store file at', cache_store_identifier, '- is the file writable?') + + +class Cryptographer: + ITERATIONS = 1_200_000 # taken from cryptography's suggestion of using Django's defaults (as of January 2025) + LEGACY_ITERATIONS = 100_000 # fallback when the iteration count is not in the config file (versions < 2023-10-17) + + def __init__(self, config, username, password): + """Creates a cryptographer which allows encrypting and decrypting sensitive information for this account, + (such as stored tokens), and also supports increasing the encryption/decryption iterations (i.e., strength)""" + self._salt = None + + # token_salt (and iterations, below) can optionally be inherited in, e.g., CCG / service account configurations + token_salt = AppConfig.get_option_with_catch_all_fallback(config, username, 'token_salt') + if token_salt: + try: + self._salt = base64.b64decode(token_salt.encode('utf-8')) # catch incorrect third-party proxy guide + except (binascii.Error, UnicodeError): + Log.info('%s: Invalid `token_salt` value found in config file entry for account %s - this value is not ' + 'intended to be manually created; generating new `token_salt`' % (APP_NAME, username)) + + if not self._salt: + self._salt = os.urandom(16) # either a failed decode or the initial run when no salt exists + + # the iteration count is stored with the credentials, so could if required be user-edited (see PR #198 comments) + iterations = int(AppConfig.get_option_with_catch_all_fallback(config, username, 'token_iterations', + fallback=self.LEGACY_ITERATIONS)) + + # with MultiFernet each fernet is tried in order to decrypt a value, but encryption always uses the first + # fernet, so sort unique iteration counts in descending order (i.e., use the best available encryption) + self._iterations_options = sorted({self.ITERATIONS, iterations, self.LEGACY_ITERATIONS}, reverse=True) + + # generate encrypter/decrypter based on the password and salt + self._fernets = [Fernet(base64.urlsafe_b64encode( + PBKDF2HMAC(algorithm=hashes.SHA256(), length=32, salt=self._salt, iterations=iterations, + backend=default_backend()).derive(password.encode('utf-8')))) for iterations in + self._iterations_options] + self.fernet = MultiFernet(self._fernets) + + @property + def salt(self): + return base64.b64encode(self._salt).decode('utf-8') + + @property + def iterations(self): + return self._iterations_options[0] + + def encrypt(self, value): + return self.fernet.encrypt(value.encode('utf-8')).decode('utf-8') + + def decrypt(self, value): + return self.fernet.decrypt(value.encode('utf-8')).decode('utf-8') + + def requires_rotation(self, value): + try: + self._fernets[0].decrypt(value.encode('utf-8')) # if the first fernet works, everything is up-to-date + return False + except InvalidToken: + try: # check to see if any fernet can decrypt the value - if so we can upgrade the encryption strength + self.decrypt(value) + return True + except InvalidToken: + return False + + def rotate(self, value): + return self.fernet.rotate(value.encode('utf-8')).decode('utf-8') + + +class OAuth2Helper: + class TokenRefreshError(Exception): + pass + + @staticmethod + def get_oauth2_credentials(username, password, reload_remote_accounts=True): + # noinspection GrazieInspection + """Using the given username (i.e., email address) and password, reads account details from AppConfig and + handles OAuth 2.0 token request and renewal, saving the updated details back to AppConfig (or removing them + if invalid). Returns either (True, '[OAuth2 string for authentication]') or (False, '[Error message]')""" + + if not password: + Log.error('No password provided for account', username, '- aborting login') + return False, '%s: Login failed - no password provided for account %s' % (APP_NAME, username) + + # we support broader catch-all account names (e.g., `@domain.com` / `@`) if enabled + config_accounts = AppConfig.accounts() + valid_accounts = [username in config_accounts] + if AppConfig.get_global('allow_catch_all_accounts', fallback=False): + user_domain = '@%s' % username.split('@')[-1] + valid_accounts.extend([account in config_accounts for account in [user_domain, '@']]) + + if not any(valid_accounts): + Log.error('Proxy config file entry missing for account', username, '- aborting login') + return (False, '%s: No config file entry found for account %s - please add a new section with values ' + 'for permission_url, token_url, oauth2_scope, redirect_uri, client_id and ' + 'client_secret' % (APP_NAME, username)) + + config = AppConfig.get() + permission_url = AppConfig.get_option_with_catch_all_fallback(config, username, 'permission_url') + token_url = AppConfig.get_option_with_catch_all_fallback(config, username, 'token_url') + oauth2_scope = AppConfig.get_option_with_catch_all_fallback(config, username, 'oauth2_scope') + oauth2_resource = AppConfig.get_option_with_catch_all_fallback(config, username, 'oauth2_resource') + oauth2_flow = AppConfig.get_option_with_catch_all_fallback(config, username, 'oauth2_flow') + redirect_uri = AppConfig.get_option_with_catch_all_fallback(config, username, 'redirect_uri') + redirect_listen_address = AppConfig.get_option_with_catch_all_fallback(config, username, + 'redirect_listen_address') + client_id = AppConfig.get_option_with_catch_all_fallback(config, username, 'client_id') + client_secret = AppConfig.get_option_with_catch_all_fallback(config, username, 'client_secret') + client_secret_encrypted = AppConfig.get_option_with_catch_all_fallback(config, username, + 'client_secret_encrypted') + use_pkce = AppConfig.get_option_with_catch_all_fallback(config, username, 'use_pkce', fallback=False) + jwt_certificate_path = AppConfig.get_option_with_catch_all_fallback(config, username, 'jwt_certificate_path') + jwt_key_path = AppConfig.get_option_with_catch_all_fallback(config, username, 'jwt_key_path') + + rewrite_oauth_username = AppConfig.get_option_with_catch_all_fallback(config, username, 'rewrite_oauth_username', username) + + # because the proxy supports a wide range of OAuth 2.0 flows, in addition to the token_url we only mandate the + # core parameters that are required by all methods: client_id and oauth2_scope (or, for non-standard ROPCG, + # currently only known to be used by 21Vianet, oauth2_resource instead of oauth2_scope - see GitHub #351) + if not (token_url and client_id and ((oauth2_flow == 'password' and oauth2_resource) or oauth2_scope)): + Log.error('Proxy config file entry incomplete for account', username, '- aborting login') + return (False, '%s: Incomplete config file entry found for account %s - please make sure all required ' + 'fields are added (at least token_url, oauth2_scope and client_id)' % (APP_NAME, username)) + + # while not technically forbidden (RFC 6749, A.1 and A.2), it is highly unlikely the example value is valid + example_client_value = '*** your' + example_client_status = [example_client_value in i for i in [client_id, client_secret] if i] + if any(example_client_status): + if all(example_client_status) or example_client_value in client_id: + Log.info('Warning: client configuration for account', username, 'seems to contain example values -', + 'if authentication fails, please double-check these values are correct') + elif example_client_value in client_secret: + Log.info('Warning: client secret for account', username, 'seems to contain the example value - if you', + 'are using an Office 365 setup that does not need a secret, please delete this line entirely;', + 'otherwise, if authentication fails, please double-check this value is correct') + + current_time = int(time.time()) + state = secrets.token_urlsafe(16) + access_token = config.get(username, 'access_token', fallback=None) + access_token_expiry = config.getint(username, 'access_token_expiry', fallback=current_time) + refresh_token = config.get(username, 'refresh_token', fallback=None) + + # try reloading remotely cached tokens if possible + if not access_token and CACHE_STORE != CONFIG_FILE_PATH and reload_remote_accounts: + AppConfig.unload() + return OAuth2Helper.get_oauth2_credentials(username, password, reload_remote_accounts=False) + + cryptographer = Cryptographer(config, username, password) + rotatable_values = { + 'access_token': access_token, + 'refresh_token': refresh_token, + 'client_secret_encrypted': client_secret_encrypted + } + if any(value and cryptographer.requires_rotation(value) for value in rotatable_values.values()): + Log.info('Rotating stored secrets for account', username, 'to use new cryptographic parameters') + for key, value in rotatable_values.items(): + if value: + config.set(username, key, cryptographer.rotate(value)) + + config.set(username, 'token_iterations', str(cryptographer.iterations)) + AppConfig.save() + + try: + # if both secret values are present we use the unencrypted version (as it may have been user-edited) + if client_secret_encrypted: + if not client_secret: + try: + client_secret = cryptographer.decrypt(client_secret_encrypted) + except InvalidToken as e: # needed to avoid looping (we don't remove secrets on decryption failure) + Log.error('Invalid password to decrypt `client_secret_encrypted` for account', username, + '- aborting login:', Log.error_string(e)) + return False, '%s: Login failed - the password for account %s is incorrect' % ( + APP_NAME, username) + else: + Log.info('Warning: found both `client_secret_encrypted` and `client_secret` for account', username, + '- the un-encrypted value will be used. Removing the un-encrypted value is recommended') + + # O365 certificate credentials - see: learn.microsoft.com/entra/identity-platform/certificate-credentials + jwt_client_assertion = None + if jwt_certificate_path and jwt_key_path: + if client_secret or client_secret_encrypted: + client_secret_type = '`client_secret%s`' % ('_encrypted' if client_secret_encrypted else '') + Log.info('Warning: found both certificate credentials and', client_secret_type, 'for account', + username, '- the', client_secret_type, 'value will be used. To use certificate', + 'credentials, remove the client secret value') + + else: + try: + # noinspection PyUnresolvedReferences + import jwt + except ImportError: + return (False, '%s: Unable to load jwt, which is a requirement when using certificate ' + 'credentials (`jwt_` options). Please run `python -m pip install -r ' + 'requirements-core.txt`' % APP_NAME) + import uuid + from cryptography import x509 + from cryptography.hazmat.primitives import serialization + + try: + jwt_now = datetime.datetime.now(datetime.timezone.utc) + jwt_certificate_fingerprint = x509.load_pem_x509_certificate( + pathlib.Path(jwt_certificate_path).read_bytes(), + backend=default_backend()).fingerprint(hashes.SHA256()) + jwt_client_assertion = jwt.encode( + { + 'aud': token_url, + 'exp': jwt_now + datetime.timedelta(seconds=JWT_LIFETIME), + 'iss': client_id, + 'jti': str(uuid.uuid4()), + 'nbf': jwt_now, + 'sub': client_id + }, + serialization.load_pem_private_key(pathlib.Path(jwt_key_path).read_bytes(), password=None), + algorithm='RS256', + headers={ + 'x5t#S256': base64.urlsafe_b64encode(jwt_certificate_fingerprint).decode('utf-8') + }) + except (FileNotFoundError, OSError): # catch OSError due to GitHub issue 257 (quoted paths) + return (False, '%s: Unable to create credentials assertion for account %s - please check that ' + 'the config file entry\'s `jwt_certificate_path` and `jwt_key_path` values are ' + 'correct' % (APP_NAME, username)) + + if access_token or refresh_token: # if possible, refresh the existing token(s) + if not access_token or access_token_expiry - current_time < TOKEN_EXPIRY_MARGIN: + if refresh_token: + response = OAuth2Helper.refresh_oauth2_access_token(token_url, client_id, client_secret, + jwt_client_assertion, username, + cryptographer.decrypt(refresh_token)) + + access_token = response['access_token'] + config.set(username, 'access_token', cryptographer.encrypt(access_token)) + config.set(username, 'access_token_expiry', str(current_time + int(response['expires_in']))) + if 'refresh_token' in response: + config.set(username, 'refresh_token', cryptographer.encrypt(response['refresh_token'])) + AppConfig.save() + + else: + # avoid trying invalid (or soon to be) tokens - we used to keep tokens until the last possible + # moment here, but it is simpler to just obtain a new one within TOKEN_EXPIRY_MARGIN, especially + # when in CCG/ROPCG/Google Cloud service account modes, for all of which getting a new token + # involves no interaction from the user (note that in interactive mode it would be better to + # request a new token via the user before discarding the existing one, but since this happens + # very infrequently, we don't add the extra complexity for just 10 extra minutes of token life) + cryptographer.decrypt(access_token) # check request is valid (raises InvalidToken on failure) + access_token = None + else: + access_token = cryptographer.decrypt(access_token) + + if not access_token: + auth_result = None + code_verifier = None + code_challenge = None + + if permission_url: # O365 CCG/ROPCG and Google service accounts skip authorisation; no permission_url + if oauth2_flow != 'device': # the device flow is a poll-based method with asynchronous interaction + oauth2_flow = 'authorization_code' + + if oauth2_flow == 'authorization_code' and use_pkce: + code_verifier = OAuth2Helper.generate_code_verifier() + code_challenge = OAuth2Helper.generate_code_challenge(code_verifier) + + permission_url = OAuth2Helper.construct_oauth2_permission_url(permission_url, redirect_uri, + client_id, oauth2_scope, username, + state, code_challenge) + + # note: get_oauth2_authorisation_code is a blocking call (waiting on user to provide code) + success, auth_result = OAuth2Helper.get_oauth2_authorisation_code(permission_url, redirect_uri, + redirect_listen_address, username, + oauth2_flow) + + if not success: + Log.info('Authorisation result error for account', username, '- aborting login.', auth_result) + return False, '%s: Login failed for account %s: %s' % (APP_NAME, username, auth_result) + + if not oauth2_flow: + Log.error('No `oauth2_flow` value specified for account', username, '- aborting login') + return (False, '%s: Incomplete config file entry found for account %s - please make sure an ' + '`oauth2_flow` value is specified when using a method that does not require a ' + '`permission_url`' % (APP_NAME, username)) + + # note: get_oauth2_authorisation_tokens may be a blocking call (DAG flow retries until user code entry) + response = OAuth2Helper.get_oauth2_authorisation_tokens(token_url, redirect_uri, client_id, + client_secret, jwt_client_assertion, + auth_result, oauth2_scope, oauth2_resource, + oauth2_flow, username, password, code_verifier) + + if AppConfig.get_global('encrypt_client_secret_on_first_use', fallback=False): + if client_secret: + # note: save to the `username` entry even if `user_domain` exists, avoiding conflicts when + # using `encrypt_client_secret_on_first_use` with the `allow_catch_all_accounts` option + config.set(username, 'client_secret_encrypted', cryptographer.encrypt(client_secret)) + config.remove_option(username, 'client_secret') + + access_token = response['access_token'] + if username not in config.sections(): + config.add_section(username) # in catch-all mode the section may not yet exist + REQUEST_QUEUE.put(MENU_UPDATE) # make sure the menu shows the newly-added account + config.set(username, 'token_salt', cryptographer.salt) + config.set(username, 'token_iterations', str(cryptographer.iterations)) + config.set(username, 'access_token', cryptographer.encrypt(access_token)) + + if 'expires_in' in response: + config.set(username, 'access_token_expiry', str(current_time + int(response['expires_in']))) + else: + Log.info('Warning: no token expiry time returned for', username, '- defaulting to', + TOKEN_LIFETIME, 'seconds') + config.set(username, 'access_token_expiry', str(current_time + TOKEN_LIFETIME)) + + if 'refresh_token' in response: + config.set(username, 'refresh_token', cryptographer.encrypt(response['refresh_token'])) + elif permission_url: # ignore this situation with CCG/ROPCG/service account flows - it is expected + Log.info('Warning: no refresh token returned for account', username, '- you will need to', + 're-authenticate each time the access token expires (does your `oauth2_scope` value allow', + '`offline` use?)') + + AppConfig.save() + + # send authentication command to server (response checked in ServerConnection) - note: we only support + # single-trip authentication (SASL) without actually checking the server's capabilities - improve? + oauth2_string = OAuth2Helper.construct_oauth2_string(rewrite_oauth_username, access_token) + return True, oauth2_string + + except OAuth2Helper.TokenRefreshError as e: + # always clear access tokens - can easily request another via the refresh token (with no user interaction) + has_access_token = bool(config.get(username, 'access_token', fallback=None)) + config.remove_option(username, 'access_token') + config.remove_option(username, 'access_token_expiry') + + if not has_access_token: + # if this is already a second failure, remove the refresh token as well, and force re-authentication + config.remove_option(username, 'token_salt') + config.remove_option(username, 'token_iterations') + config.remove_option(username, 'refresh_token') + + AppConfig.save() + + Log.info('Retrying login due to exception while refreshing access token for account', username, + '(attempt %d):' % (1 if has_access_token else 2), Log.error_string(e)) + return OAuth2Helper.get_oauth2_credentials(username, password, reload_remote_accounts=False) + + except InvalidToken as e: + # regardless of the `delete_account_token_on_password_error` setting, we only reset tokens for standard or + # ROPCG flows; when using CCG or a service account it is far safer to deny account access and require a + # config file edit in order to reset an account rather than allowing *any* password to be used for access + if AppConfig.get_global('delete_account_token_on_password_error', fallback=True) and ( + permission_url or oauth2_flow not in ['client_credentials', 'service_account']): + config.remove_option(username, 'access_token') + config.remove_option(username, 'access_token_expiry') + config.remove_option(username, 'token_salt') + config.remove_option(username, 'token_iterations') + config.remove_option(username, 'refresh_token') + AppConfig.save() + + Log.info('Retrying login due to exception while decrypting OAuth 2.0 credentials for account', username, + '(invalid password):', Log.error_string(e)) + return OAuth2Helper.get_oauth2_credentials(username, password, reload_remote_accounts=False) + + Log.error('Invalid password to decrypt credentials for account', username, '- aborting login:', + Log.error_string(e)) + return False, '%s: Login failed - the password for account %s is incorrect' % (APP_NAME, username) + + except Exception as e: + # note that we don't currently remove cached credentials here, as failures on the initial request are before + # caching happens, and the assumption is that refresh token request exceptions are temporal (e.g., network + # errors: URLError(OSError(50, 'Network is down'))) - access token 400 Bad Request HTTPErrors with messages + # such as 'authorisation code was already redeemed' are caused by our support for simultaneous requests, + # and will work from the next request; however, please report an issue if you encounter problems here + Log.info('Caught exception while requesting OAuth 2.0 credentials for account %s:' % username, + Log.error_string(e)) + if isinstance(e, json.JSONDecodeError): + Log.debug('JSON string that triggered this exception:', e.doc) + return False, '%s: Login failed for account %s - please check your internet connection and retry' % ( + APP_NAME, username) + + @staticmethod + def oauth2_url_escape(text): + return urllib.parse.quote(text, safe='~-._') # see https://tools.ietf.org/html/rfc3986#section-2.3 + + @staticmethod + def oauth2_url_unescape(text): + return urllib.parse.unquote(text) + + @staticmethod + def match_redirect_uri(config, received): + parsed_config = urllib.parse.urlparse(config) + parsed_received = urllib.parse.urlparse(received) + # match host:port and path (except trailing slashes), but allow mismatch of the scheme (i.e., http/https) (#96) + return parsed_config.netloc == parsed_received.netloc and parsed_config.path.rstrip( + '/') == parsed_received.path.rstrip('/') + + @staticmethod + def start_redirection_receiver_server(token_request): + """Starts a local WSGI web server to receive OAuth responses""" + redirect_listen_type = 'redirect_listen_address' if token_request['redirect_listen_address'] else 'redirect_uri' + parsed_uri = urllib.parse.urlparse(token_request[redirect_listen_type]) + parsed_port = 80 if parsed_uri.port is None else parsed_uri.port + Log.debug('Local server auth mode (%s): starting server to listen for authentication response' % + Log.format_host_port((parsed_uri.hostname, parsed_port))) + + class LoggingWSGIRequestHandler(wsgiref.simple_server.WSGIRequestHandler): + # pylint: disable-next=arguments-differ + def log_message(self, _format_string, *args): + Log.debug('Local server auth mode (%s): received authentication response' % Log.format_host_port( + (parsed_uri.hostname, parsed_port)), *args) + + class RedirectionReceiverWSGIApplication: + def __call__(self, environ, start_response): + start_response('200 OK', [('Content-type', 'text/html; charset=utf-8')]) + token_request['response_url'] = '/'.join(token_request['redirect_uri'].split('/')[0:3]) + environ.get( + 'PATH_INFO') + '?' + environ.get('QUERY_STRING') + return [('%s authentication complete (%s)

%s successfully authenticated account %s.

You can close this ' + 'window.

' % ((APP_NAME, token_request['username']) * 2)).encode('utf-8')] + + try: + wsgiref.simple_server.WSGIServer.allow_reuse_address = False + wsgiref.simple_server.WSGIServer.timeout = AUTHENTICATION_TIMEOUT + redirection_server = wsgiref.simple_server.make_server(str(parsed_uri.hostname), parsed_port, + RedirectionReceiverWSGIApplication(), + handler_class=LoggingWSGIRequestHandler) + + Log.info('Please visit the following URL to authenticate account %s: %s' % + (token_request['username'], token_request['permission_url'])) + redirection_server.handle_request() + with contextlib.suppress(socket.error): + redirection_server.server_close() + + if 'response_url' in token_request: + Log.debug('Local server auth mode (%s): closing local server and returning response' % + Log.format_host_port((parsed_uri.hostname, parsed_port)), token_request['response_url']) + else: + # failed, likely because of an incorrect address (e.g., https vs http), but can also be due to timeout + Log.info('Local server auth mode (%s):' % Log.format_host_port((parsed_uri.hostname, parsed_port)), + 'request failed - if this error reoccurs, please check `%s` for' % redirect_listen_type, + token_request['username'], 'is not specified as `https` mistakenly. See the sample ' + 'configuration file for documentation') + token_request['expired'] = True + + except socket.error as e: + Log.error('Local server auth mode (%s):' % Log.format_host_port((parsed_uri.hostname, parsed_port)), + 'unable to start local server. Please check that `%s` for %s is unique across accounts, ' + 'specifies a port number, and is not already in use. See the documentation in the proxy\'s ' + 'sample configuration file.' % (redirect_listen_type, token_request['username']), + Log.error_string(e)) + token_request['expired'] = True + + del token_request['local_server_auth'] + RESPONSE_QUEUE.put(token_request) + + @staticmethod + def construct_oauth2_permission_url(permission_url, redirect_uri, client_id, scope, username, state, + code_challenge): + """Constructs and returns the URL to request permission for this client to access the given scope, hinting + the username where possible (note that delegated accounts without direct login enabled will need to select the + 'Sign in with another account' option)""" + params = {'client_id': client_id, 'redirect_uri': redirect_uri, 'scope': scope, 'response_type': 'code', + 'access_type': 'offline', 'login_hint': username} + if state: + params['state'] = state + if code_challenge: # PKCE; see RFC 7636 + params['code_challenge'] = code_challenge + params['code_challenge_method'] = 'S256' + if not redirect_uri: # unlike other interactive flows, DAG doesn't involve a (known) final redirect + del params['redirect_uri'] + param_pairs = ['%s=%s' % (param, OAuth2Helper.oauth2_url_escape(value)) for param, value in params.items()] + return '%s?%s' % (permission_url, '&'.join(param_pairs)) + + @staticmethod + def start_device_authorisation_grant(permission_url): + """Requests the device authorisation grant flow URI and user code - see https://tools.ietf.org/html/rfc8628""" + try: + response = urllib.request.urlopen( + urllib.request.Request(permission_url, headers={'User-Agent': APP_NAME}), + timeout=AUTHENTICATION_TIMEOUT).read() + parsed_result = json.loads(response) + verification_uri = parsed_result.get('verification_uri_complete', parsed_result['verification_uri']) + user_code = parsed_result['user_code'] + return True, parsed_result, verification_uri, user_code + except urllib.error.HTTPError as e: + return False, json.loads(e.read()), None, None + + @staticmethod + def get_oauth2_authorisation_code(permission_url, redirect_uri, redirect_listen_address, username, oauth2_flow): + """Submit an authorisation request to the parent app and block until it is provided (or the request fails)""" + + # the device authorisation grant flow requires a bit of pre-precessing to get the actual permission URL + user_code, device_grant_result = None, None + if oauth2_flow == 'device': + success, device_grant_result, permission_url, user_code = OAuth2Helper.start_device_authorisation_grant( + permission_url) + if not success: + return False, device_grant_result + + token_request = {'permission_url': permission_url, 'user_code': user_code, 'redirect_uri': redirect_uri, + 'redirect_listen_address': redirect_listen_address, 'username': username, 'expired': False} + REQUEST_QUEUE.put(token_request) + response_queue_reference = RESPONSE_QUEUE # referenced locally to avoid inserting into the new queue on restart + wait_time = 0 + while True: + try: + data = response_queue_reference.get(block=True, timeout=1) + except queue.Empty: + wait_time += 1 + if wait_time < AUTHENTICATION_TIMEOUT: + continue + + token_request['expired'] = True + REQUEST_QUEUE.put(token_request) # re-insert the request as expired so the parent app can remove it + return False, 'Authorisation request timed out' + + # noinspection PyUnboundLocalVariable + if data is QUEUE_SENTINEL: # app is closing + response_queue_reference.put(QUEUE_SENTINEL) # make sure all watchers exit + return False, '%s is shutting down' % APP_NAME + + # noinspection PyUnboundLocalVariable + if data['permission_url'] == permission_url and data['username'] == username: # a response meant for us + # to improve no-GUI mode we also support the use of a local redirection receiver server or terminal + # entry to authenticate; this result is a timeout, wsgi request error/failure, or terminal auth ctrl+c + if 'expired' in data and data['expired']: + return False, 'No-GUI authorisation request failed or timed out for account %s' % data['username'] + + if 'local_server_auth' in data: + threading.Thread(target=OAuth2Helper.start_redirection_receiver_server, args=(data,), + name='EmailOAuth2Proxy-auth-%s' % data['username'], daemon=True).start() + + elif oauth2_flow == 'device': + return True, device_grant_result + + else: + if 'response_url' in data and OAuth2Helper.match_redirect_uri(token_request['redirect_uri'], + data['response_url']): + # parse_qsl not parse_qs because we only ever care about non-array values; extra dict formatting + # as IntelliJ has a bug incorrectly detecting parse_qs/l as returning a dict with byte-type keys + response = {str(key): value for key, value in + urllib.parse.parse_qsl(urllib.parse.urlparse(data['response_url']).query)} + if 'code' in response and response['code']: + # note: we don't check `state` as it is embedded in `permission_url` which we *do* check + authorisation_code = OAuth2Helper.oauth2_url_unescape(response['code']) + if authorisation_code: + return True, authorisation_code + return False, 'No OAuth 2.0 authorisation code returned for account %s' % data['username'] + if 'error' in response: + message = 'OAuth 2.0 authorisation error for account %s: ' % data['username'] + message += response['error'] + message += '; %s' % response.get('error_description', '') + return False, message + return (False, 'OAuth 2.0 authorisation response for account %s has neither code nor error ' + 'message' % data['username']) + return (False, 'OAuth 2.0 authorisation response for account %s is missing or does not match' + '`redirect_uri`' % data['username']) + + else: # not for this thread - put back into queue + response_queue_reference.put(data) + time.sleep(1) + + @staticmethod + # pylint: disable-next=too-many-positional-arguments + def get_oauth2_authorisation_tokens(token_url, redirect_uri, client_id, client_secret, jwt_client_assertion, + authorisation_result, oauth2_scope, oauth2_resource, oauth2_flow, username, + password, code_verifier): + """Requests OAuth 2.0 access and refresh tokens from token_url using the given client_id, client_secret, + authorisation_code and redirect_uri, returning a dict with 'access_token', 'expires_in', and 'refresh_token' + on success, or throwing an exception on failure (e.g., HTTP 400)""" + + # service accounts are slightly different, and are handled separately + if oauth2_flow == 'service_account': + return OAuth2Helper.get_service_account_authorisation_token(client_id, client_secret, oauth2_scope, + username) + + params = {'client_id': client_id, 'client_secret': client_secret, 'code': authorisation_result, + 'redirect_uri': redirect_uri, 'grant_type': oauth2_flow} + expires_in = AUTHENTICATION_TIMEOUT + + if code_verifier: + params['code_verifier'] = code_verifier # PKCE; see RFC 7636 + + if not client_secret: + del params['client_secret'] # client secret can be optional for O365, but we don't want a None entry + + # certificate credentials are only used when no client secret is provided + if jwt_client_assertion: + params['client_assertion_type'] = 'urn:ietf:params:oauth:client-assertion-type:jwt-bearer' + params['client_assertion'] = jwt_client_assertion + + # CCG flow can fall back to the login password as the client secret (see GitHub #271 discussion) + elif oauth2_flow == 'client_credentials' and AppConfig.get_global( + 'use_login_password_as_client_credentials_secret', fallback=False): + params['client_secret'] = password + + if oauth2_flow != 'authorization_code': + del params['code'] # CCG/ROPCG flows have no code, but we need the scope and (for ROPCG) username+password + params['scope'] = oauth2_scope + if oauth2_flow == 'device': + params['grant_type'] = 'urn:ietf:params:oauth:grant-type:device_code' + params['device_code'] = authorisation_result['device_code'] + expires_in = int(authorisation_result['expires_in']) # unlike code requests, DAG *requires* expires_in + authorisation_result['interval'] = authorisation_result.get('interval', 5) # see RFC 8628, Section 3.2 + elif oauth2_flow == 'password': + params['username'] = username + params['password'] = password + # there is at least one non-standard implementation of ROPCG that uses a resource parameter instead of a + # scope (e.g., 21Vianet's version of O365; see GitHub #351) - note that it is not known whether this is + # always instead of the scope value or potentially in addition to it, so we only remove if not specified + if oauth2_resource: + params['resource'] = oauth2_resource + if not oauth2_scope: + del params['scope'] + if not redirect_uri: + del params['redirect_uri'] # redirect_uri is not typically required in non-code flows; remove if empty + + # the device flow requires repeatedly polling the service while the result is pending + expires_at = time.time() + expires_in + while time.time() < expires_at and not EXITING: + try: + # in all flows except DAG, we make one attempt only + response = urllib.request.urlopen( + urllib.request.Request(token_url, data=urllib.parse.urlencode(params).encode('utf-8'), + headers={'User-Agent': APP_NAME}), timeout=AUTHENTICATION_TIMEOUT).read() + return json.loads(response) + + except urllib.error.HTTPError as e: + e.message = json.loads(e.read()) + if oauth2_flow == 'device' and e.code == 400: + if e.message['error'] == 'slow_down': + authorisation_result['interval'] *= 2 + continue + if e.message['error'] == 'authorization_pending': + Log.debug('Waiting for device flow confirmation for account', username, '- retrying in', + '%ds; timeout in %ds' % (authorisation_result['interval'], expires_at - time.time())) + time.sleep(authorisation_result['interval']) + continue + + Log.debug('Error requesting access token for account', username, '- received invalid response:', + e.message) + raise e + + raise TimeoutError('The access token request for account', username, 'timed out') + + # noinspection PyUnresolvedReferences + @staticmethod + def get_service_account_authorisation_token(key_type, key_path_or_contents, oauth2_scope, username): + """Requests an authorisation token via a Service Account key (currently Google Cloud only)""" + try: + import requests # noqa: F401 - requests is required as the default transport for google-auth + import google.oauth2.service_account + import google.auth.transport.requests + except ModuleNotFoundError as e: + raise ModuleNotFoundError('Unable to load Google Auth SDK - please install the `requests` and ' + '`google-auth` modules: `python -m pip install requests google-auth`') from e + + if key_type == 'file': + try: + with open(key_path_or_contents, mode='r', encoding='utf-8') as key_file: + service_account = json.load(key_file) + except IOError as e: + raise FileNotFoundError('Unable to open service account key file %s for account %s' % + (key_path_or_contents, username)) from e + elif key_type == 'key': + service_account = json.loads(key_path_or_contents) + else: + raise KeyError('Service account key type not specified for account %s - `client_id` must be set to ' + '`file` or `key`' % username) + + credentials = google.oauth2.service_account.Credentials.from_service_account_info(service_account) + credentials = credentials.with_scopes(oauth2_scope.split(' ')) + credentials = credentials.with_subject(username) + + request = google.auth.transport.requests.Request() + credentials.refresh(request) + return {'access_token': credentials.token, 'expires_in': credentials.expiry.timestamp() - time.time()} + + @staticmethod + # pylint: disable-next=too-many-positional-arguments + def refresh_oauth2_access_token(token_url, client_id, client_secret, jwt_client_assertion, username, refresh_token): + """Obtains a new access token from token_url using the given client_id, client_secret and refresh token, + returning a dict with 'access_token', 'expires_in', and 'refresh_token' on success; exception on failure""" + params = {'client_id': client_id, 'client_secret': client_secret, 'refresh_token': refresh_token, + 'grant_type': 'refresh_token'} + if not client_secret: + del params['client_secret'] # client secret can be optional for O365, but we don't want a None entry + + # certificate credentials are only used when no client secret is provided + if jwt_client_assertion: + params['client_assertion_type'] = 'urn:ietf:params:oauth:client-assertion-type:jwt-bearer' + params['client_assertion'] = jwt_client_assertion + + try: + response = urllib.request.urlopen( + urllib.request.Request(token_url, data=urllib.parse.urlencode(params).encode('utf-8'), + headers={'User-Agent': APP_NAME}), timeout=AUTHENTICATION_TIMEOUT).read() + token = json.loads(response) + + # note: some servers return expiry as a string (GitHub #237); others omit this (but we still need to renew) + token['expires_in'] = token['expires_in'] if 'expires_in' in token else TOKEN_LIFETIME + + return token + + except urllib.error.HTTPError as e: + e.message = json.loads(e.read()) + Log.debug('Error refreshing access token for account', username, '- received invalid response:', e.message) + if e.code == 400: # 400 Bad Request typically means re-authentication is required (token expired) + raise OAuth2Helper.TokenRefreshError from e + raise e + + @staticmethod + def construct_oauth2_string(username, access_token): + """Constructs an OAuth 2.0 SASL authentication string from the given username and access token""" + return 'user=%s\1auth=Bearer %s\1\1' % (username, access_token) + + @staticmethod + def encode_oauth2_string(input_string): + """We use encode() from imaplib's _Authenticator, but it is a private class so we shouldn't just import it. That + method's docstring is: + Invoke binascii.b2a_base64 iteratively with short even length buffers, strip the trailing line feed from + the result and append. 'Even' means a number that factors to both 6 and 8, so when it gets to the end of + the 8-bit input there's no partial 6-bit output.""" + output_bytes = b'' + if isinstance(input_string, str): + input_string = input_string.encode('utf-8') + while input_string: + if len(input_string) > 48: + t = input_string[:48] + input_string = input_string[48:] + else: + t = input_string + input_string = b'' + e = binascii.b2a_base64(t) + if e: + output_bytes = output_bytes + e[:-1] + return output_bytes + + @staticmethod + def strip_quotes(text): + """Remove double quotes (i.e., "" characters) around a string - used for IMAP LOGIN command""" + if text.startswith('"') and text.endswith('"'): + return text[1:-1].replace(r'\"', '"') # also need to fix any escaped quotes within the string + return text + + @staticmethod + def decode_credentials(str_data): + """Decode credentials passed as a base64-encoded string: [some data we don't need]\x00username\x00password""" + try: + # formal syntax: https://tools.ietf.org/html/rfc4616#section-2 + _, bytes_username, bytes_password = base64.b64decode(str_data).split(b'\x00') + return bytes_username.decode('utf-8'), bytes_password.decode('utf-8') + except (ValueError, binascii.Error): + # ValueError is from incorrect number of arguments; binascii.Error from incorrect encoding + return '', '' # no (or invalid) credentials provided + + @staticmethod + def generate_code_verifier(): + # RFC 7636 (4.1): between 43 and 128 characters (inclusive) using only unreserved URI characters (see RFC 3986) + return base64.urlsafe_b64encode(secrets.token_bytes(64)).rstrip(b'=').decode('utf-8') + + @staticmethod + def generate_code_challenge(verifier): + digest = hashlib.sha256(verifier.encode('utf-8')).digest() + return base64.urlsafe_b64encode(digest).rstrip(b'=').decode('utf-8') + + +class SSLAsyncoreDispatcher(asyncore.dispatcher_with_send): + def __init__(self, connection_socket=None, socket_map=None): + asyncore.dispatcher_with_send.__init__(self, sock=connection_socket, map=socket_map) + self.ssl_handshake_errors = (ssl.SSLWantReadError, ssl.SSLWantWriteError, + ssl.SSLEOFError, ssl.SSLZeroReturnError) + self.ssl_connection, self.ssl_handshake_attempts, self.ssl_handshake_completed = self._reset() + + def _reset(self, is_ssl=False): + self.ssl_connection = is_ssl + self.ssl_handshake_attempts = 0 + self.ssl_handshake_completed = not is_ssl + return self.ssl_connection, self.ssl_handshake_attempts, self.ssl_handshake_completed + + def info_string(self): + return 'SSLDispatcher' # override in subclasses to provide more detailed connection information + + def set_ssl_connection(self, is_ssl=False): + # note that the actual SSLContext.wrap_socket (and associated unwrap()) are handled outside this class + if not self.ssl_connection and is_ssl: + self._reset(True) + if is_ssl: + # we don't start negotiation here because a failed handshake in __init__ means remove_client also fails + Log.debug(self.info_string(), '<-> [ Starting TLS handshake ]') + + elif self.ssl_connection and not is_ssl: + self._reset() + + def _ssl_handshake(self): + if not isinstance(self.socket, ssl.SSLSocket): + Log.error(self.info_string(), 'Unable to initiate handshake with a non-SSL socket; aborting') + raise ssl.SSLError(-1, APP_PACKAGE) + + # attempting to connect insecurely to a secure socket could loop indefinitely here - we set a maximum attempt + # count and catch in handle_error() when `ssl_handshake_attempts` expires, but there's not much else we can do + self.ssl_handshake_attempts += 1 + if 0 < MAX_SSL_HANDSHAKE_ATTEMPTS < self.ssl_handshake_attempts: + Log.error(self.info_string(), 'SSL socket handshake failed (reached `MAX_SSL_HANDSHAKE_ATTEMPTS`)') + raise ssl.SSLError(-1, APP_PACKAGE) + + # see: https://github.com/python/cpython/issues/54293 + try: + self.socket.do_handshake() + except ssl.SSLWantReadError: + select.select([self.socket], [], [], 0.01) # wait for the socket to be readable (10ms timeout) + except ssl.SSLWantWriteError: + select.select([], [self.socket], [], 0.01) # wait for the socket to be writable (10ms timeout) + except self.ssl_handshake_errors: # also includes SSLWant[Read/Write]Error, but already handled above + self.close() + else: + if not self.ssl_handshake_completed: # only notify once (we may need to repeat the handshake later) + Log.debug(self.info_string(), '<-> [', self.socket.version(), 'handshake complete ]') + self.ssl_handshake_attempts = 0 + self.ssl_handshake_completed = True + + def handle_read_event(self): + # additional Exceptions are propagated to handle_error(); no need to handle here + if not self.ssl_handshake_completed: + self._ssl_handshake() + else: + # on the first connection event to a secure server we need to handle SSL handshake events (because we don't + # have a 'not_currently_ssl_but_will_be_once_connected'-type state) - a version of this class that didn't + # have to deal with both unsecured, wrapped *and* STARTTLS-type sockets would only need this in recv/send + try: + super().handle_read_event() + except self.ssl_handshake_errors: + self._ssl_handshake() + + def handle_write_event(self): + # additional Exceptions are propagated to handle_error(); no need to handle here + if not self.ssl_handshake_completed: + self._ssl_handshake() + else: + # as in handle_read_event, we need to handle SSL handshake events + try: + super().handle_write_event() + except self.ssl_handshake_errors: + self._ssl_handshake() + + def recv(self, buffer_size): + # additional Exceptions are propagated to handle_error(); no need to handle here + try: + return super().recv(buffer_size) + except self.ssl_handshake_errors: + self._ssl_handshake() + return b'' + + def send(self, byte_data): + # additional Exceptions are propagated to handle_error(); no need to handle here + try: + return super().send(byte_data) # buffers before sending via the socket, so failure is okay; will auto-retry + except self.ssl_handshake_errors: + self._ssl_handshake() + return 0 + + def handle_error(self): + if self.ssl_connection: + # OSError 0 ('Error') and SSL errors here are caused by connection handshake failures or timeouts + # APP_PACKAGE is used when we throw our own SSLError on handshake timeout or socket misconfiguration + ssl_errors = ['SSLV3_ALERT_BAD_CERTIFICATE', 'PEER_DID_NOT_RETURN_A_CERTIFICATE', 'WRONG_VERSION_NUMBER', + 'CERTIFICATE_VERIFY_FAILED', 'TLSV1_ALERT_PROTOCOL_VERSION', 'TLSV1_ALERT_UNKNOWN_CA', + 'UNSUPPORTED_PROTOCOL', 'record layer failure', APP_PACKAGE] + error_type, value = Log.get_last_error() + if error_type is OSError and value.errno == 0 or issubclass(error_type, ssl.SSLError) and \ + any(i in value.args[1] for i in ssl_errors) or error_type is FileNotFoundError: + Log.error('Caught connection error in', self.info_string(), ':', error_type, 'with message:', value) + if hasattr(self, 'custom_configuration') and hasattr(self, 'proxy_type'): + if self.proxy_type == 'SMTP': + Log.error('Are the server\'s `local_starttls` and `server_starttls` settings correct?', + 'Current `local_starttls` value: %s;' % self.custom_configuration['local_starttls'], + 'current `server_starttls` value:', self.custom_configuration['server_starttls']) + if self.custom_configuration['local_certificate_path'] and \ + self.custom_configuration['local_key_path']: + Log.error('You have set `local_certificate_path` and `local_key_path`: is your client using a', + 'secure connection? github.com/FiloSottile/mkcert is highly recommended for local', + 'self-signed certificates, but these may still need an exception in your client') + Log.error('If you encounter this error repeatedly, please check that you have correctly configured', + 'python root certificates; see: https://github.com/simonrob/email-oauth2-proxy/issues/14') + self.close() + else: + super().handle_error() + else: + super().handle_error() + + +class OAuth2ClientConnection(SSLAsyncoreDispatcher): + """The base client-side connection that is subclassed to handle IMAP/POP/SMTP client interaction (note that there + is some protocol-specific code in here, but it is not essential, and only used to avoid logging credentials)""" + + # pylint: disable-next=too-many-positional-arguments + def __init__(self, proxy_type, connection_socket, socket_map, proxy_parent, custom_configuration): + SSLAsyncoreDispatcher.__init__(self, connection_socket=connection_socket, socket_map=socket_map) + self.receive_buffer = b'' + self.proxy_type = proxy_type + self.server_connection = None + self.proxy_parent = proxy_parent + self.local_address = proxy_parent.local_address + self.server_address = proxy_parent.server_address + self.custom_configuration = custom_configuration + self.debug_address_string = '%s-{%s}-%s' % tuple(map(Log.format_host_port, ( + connection_socket.getpeername(), connection_socket.getsockname(), self.server_address))) + + self.censor_next_log = False # try to avoid logging credentials + self.authenticated = False + + self.set_ssl_connection( + bool(not custom_configuration['local_starttls'] and custom_configuration['local_certificate_path'] and + custom_configuration['local_key_path'])) + + def info_string(self): + debug_string = self.debug_address_string if Log.get_level() == logging.DEBUG else \ + Log.format_host_port(self.local_address) + account = '; %s' % self.server_connection.authenticated_username if \ + self.server_connection and self.server_connection.authenticated_username else '' + return '%s (%s%s)' % (self.proxy_type, debug_string, account) + + def handle_read(self): + byte_data = self.recv(RECEIVE_BUFFER_SIZE) + if not byte_data: + return + + # client is established after server; this state should not happen unless already closing + if not self.server_connection: + Log.debug(self.info_string(), 'Data received without server connection - ignoring and closing:', byte_data) + self.close() + return + + # we have already authenticated - nothing to do; just pass data directly to server + if self.authenticated: + Log.debug(self.info_string(), '-->', byte_data) + OAuth2ClientConnection.process_data(self, byte_data) + + # if not authenticated, buffer incoming data and process line-by-line (slightly more involved than the server + # connection because we censor commands that contain passwords or authentication tokens) + else: + self.receive_buffer += byte_data + complete_lines = [] + while True: + terminator_index = self.receive_buffer.find(LINE_TERMINATOR) + if terminator_index != -1: + split_position = terminator_index + LINE_TERMINATOR_LENGTH + complete_lines.append(self.receive_buffer[:split_position]) + self.receive_buffer = self.receive_buffer[split_position:] + else: + break + + for line in complete_lines: + # try to remove credentials from logged data - both inline (via regex) and as separate requests + if self.censor_next_log: + log_data = CENSOR_MESSAGE + self.censor_next_log = False + else: + # IMAP LOGIN command with inline username/password, POP PASS and IMAP/POP/SMTP AUTH(ENTICATE) + tag_pattern = IMAP_TAG_PATTERN.encode('utf-8') + log_data = re.sub(b'(%s) (LOGIN) (.*)\r\n' % tag_pattern, + br'\1 \2 ' + CENSOR_MESSAGE + b'\r\n', line, flags=re.IGNORECASE) + log_data = re.sub(b'(PASS) (.*)\r\n', + br'\1 ' + CENSOR_MESSAGE + b'\r\n', log_data, flags=re.IGNORECASE) + log_data = re.sub(b'(%s)?( )?(AUTH)(ENTICATE)? (PLAIN|LOGIN) (.*)\r\n' % tag_pattern, + br'\1\2\3\4 \5 ' + CENSOR_MESSAGE + b'\r\n', log_data, flags=re.IGNORECASE) + + Log.debug(self.info_string(), '-->', log_data if CENSOR_CREDENTIALS else line) + try: + self.process_data(line) + except AttributeError: # AttributeError("'NoneType' object has no attribute 'username'"), etc + Log.info(self.info_string(), + 'Caught client exception in subclass; server connection closed before data could be sent') + self.close() + break + + def process_data(self, byte_data, censor_server_log=False): + try: + self.server_connection.send(byte_data, censor_log=censor_server_log) # default = send everything to server + except AttributeError: # AttributeError("'NoneType' object has no attribute 'send'") + Log.info(self.info_string(), 'Caught client exception; server connection closed before data could be sent') + self.close() + + def send(self, byte_data): + Log.debug(self.info_string(), '<--', byte_data) + return super().send(byte_data) + + def log_info(self, message, message_type='info'): + # override to redirect error messages to our own log + if message_type not in self.ignore_log_types: + Log.info(self.info_string(), 'Caught asyncore info message (client) -', message_type, ':', message) + + def handle_close(self): + error_type, value = Log.get_last_error() + if error_type and value: + message = 'Caught connection error (client)' + if error_type is ConnectionResetError: + message = '%s [ Are you attempting an encrypted connection to a non-encrypted server? ]' % message + Log.info(self.info_string(), message, '-', error_type.__name__, ':', value) + self.close() + + def close(self): + if self.server_connection: + self.server_connection.client_connection = None + with contextlib.suppress(AttributeError): + self.server_connection.close() + self.server_connection = None + self.proxy_parent.remove_client(self) + with contextlib.suppress(OSError): + Log.debug(self.info_string(), '<-- [ Server disconnected ]') + super().close() + + +class IMAPOAuth2ClientConnection(OAuth2ClientConnection): + """The client side of the connection - intercept LOGIN/AUTHENTICATE commands and replace with OAuth 2.0 SASL""" + + def __init__(self, connection_socket, socket_map, proxy_parent, custom_configuration): + super().__init__('IMAP', connection_socket, socket_map, proxy_parent, custom_configuration) + self.authentication_tag = None + (self.authentication_command, self.awaiting_credentials, self.login_literal_length_awaited, + self.login_literal_username) = self.reset_login_state() + + def reset_login_state(self): + self.authentication_command = None + self.awaiting_credentials = False + self.login_literal_length_awaited = 0 + self.login_literal_username = None + return (self.authentication_command, self.awaiting_credentials, self.login_literal_length_awaited, + self.login_literal_username) # avoid lint complaint about defining outside init + + def process_data(self, byte_data, censor_server_log=False): + str_data = byte_data.decode('utf-8', 'replace').rstrip('\r\n') + + # LOGIN data can be sent as quoted text or string literals (https://tools.ietf.org/html/rfc9051#section-4.3) + if self.login_literal_length_awaited > 0: + if not self.login_literal_username: + split_string = str_data.split(' ') + literal_match = IMAP_LITERAL_MATCHER.match(split_string[-1]) + if literal_match and len(byte_data) > self.login_literal_length_awaited + 2: + # could be the username and another literal for password (+2: literal length doesn't include \r\n) + # note: plaintext password could end with a string such as ` {1}` that is a valid literal length + self.login_literal_username = ' '.join(split_string[:-1]) # handle username space errors elsewhere + self.login_literal_length_awaited = int(literal_match.group('length')) + self.censor_next_log = True + if not literal_match.group('continuation'): + self.send(b'+ \r\n') # request data (RFC 7888's non-synchronising literals don't require this) + elif len(split_string) > 1: + # credentials as a single literal doesn't seem to be valid (RFC 9051), but some clients do this + self.login_literal_length_awaited = 0 + self.authenticate_connection(split_string[0], ' '.join(split_string[1:])) + else: + super().process_data(byte_data) # probably an invalid command, but just let the server handle it + + else: + # no need to check length - can only be password; no more literals possible (unless \r\n *in* password) + self.login_literal_length_awaited = 0 + self.authenticate_connection(self.login_literal_username, str_data) + + # AUTHENTICATE PLAIN can be a two-stage request - handle credentials if they are separate from command + elif self.awaiting_credentials: + self.awaiting_credentials = False + username, password = OAuth2Helper.decode_credentials(str_data) + self.authenticate_connection(username, password, 'authenticate') + + else: + match = IMAP_AUTHENTICATION_REQUEST_MATCHER.match(str_data) + if not match: # probably an invalid command, but just let the server handle it + super().process_data(byte_data) + return + + self.authentication_command = match.group('command').lower() + client_flags = match.group('flags') + if self.authentication_command == 'login': + # string literals are sent as a separate message from the client - note that while length is specified + # we don't actually check this, instead relying on \r\n as usual (technically, as per RFC 9051 (4.3) the + # string literal value can itself contain \r\n, but since the proxy only cares about usernames/passwords + # and it is highly unlikely these will contain \r\n, it is probably safe to avoid this extra complexity) + split_flags = client_flags.split(' ') + literal_match = IMAP_LITERAL_MATCHER.match(split_flags[-1]) + if literal_match: + self.authentication_tag = match.group('tag') + if len(split_flags) > 1: + # email addresses will not contain spaces, but let error checking elsewhere handle that - the + # important thing is any non-literal here *must* be the username (else no need for a literal) + self.login_literal_username = ' '.join(split_flags[:-1]) + self.login_literal_length_awaited = int(literal_match.group('length')) + self.censor_next_log = True + if not literal_match.group('continuation'): + self.send(b'+ \r\n') # request data (RFC 7888's non-synchronising literals don't require this) + + # technically only double-quoted strings are allowed here according to RFC 9051 (4.3), but some clients + # do not obey this - we mandate email addresses as usernames (i.e., no spaces), so can be more flexible + elif len(split_flags) > 1: + username = OAuth2Helper.strip_quotes(split_flags[0]) + password = OAuth2Helper.strip_quotes(' '.join(split_flags[1:])) + self.authentication_tag = match.group('tag') + self.authenticate_connection(username, password) + else: + # wrong number of arguments - let the server handle the error + super().process_data(byte_data) + + elif self.authentication_command == 'authenticate': + split_flags = client_flags.split(' ') + authentication_type = split_flags[0].lower() + if authentication_type == 'plain': # plain can be submitted as a single command or multiline + self.authentication_tag = match.group('tag') + if len(split_flags) > 1: + username, password = OAuth2Helper.decode_credentials(' '.join(split_flags[1:])) + self.authenticate_connection(username, password, command=self.authentication_command) + else: + self.awaiting_credentials = True + self.censor_next_log = True + self.send(b'+ \r\n') # request credentials (note: space after response code is mandatory) + else: + # we don't support any other methods - let the server handle this + super().process_data(byte_data) + + else: + # we haven't yet authenticated, but this is some other matched command - pass through + super().process_data(byte_data) + + def authenticate_connection(self, username, password, command='login'): + success, result = OAuth2Helper.get_oauth2_credentials(username, password) + if success: + # send authentication command to server (response checked in ServerConnection) + # note: we only support single-trip authentication (SASL) without checking server capabilities - improve? + super().process_data(b'%s AUTHENTICATE XOAUTH2 ' % self.authentication_tag.encode('utf-8')) + super().process_data(b'%s\r\n' % OAuth2Helper.encode_oauth2_string(result), censor_server_log=True) + + # because get_oauth2_credentials blocks, the server could have disconnected, and may no-longer exist + if self.server_connection: + self.server_connection.authenticated_username = username + + self.reset_login_state() + if not success: + error_message = '%s NO %s %s\r\n' % (self.authentication_tag, command.upper(), result) + self.authentication_tag = None + self.send(error_message.encode('utf-8')) + + +class POPOAuth2ClientConnection(OAuth2ClientConnection): + """The client side of the connection - watch for AUTH, USER and PASS commands and replace with OAuth 2.0""" + + class STATE(enum.Enum): + PENDING = 1 + CAPA_AWAITING_RESPONSE = 2 + AUTH_PLAIN_AWAITING_CREDENTIALS = 3 + USER_AWAITING_PASS = 4 + XOAUTH2_AWAITING_CONFIRMATION = 5 + XOAUTH2_CREDENTIALS_SENT = 6 + + def __init__(self, connection_socket, socket_map, proxy_parent, custom_configuration): + super().__init__('POP', connection_socket, socket_map, proxy_parent, custom_configuration) + self.connection_state = self.STATE.PENDING + + def process_data(self, byte_data, censor_server_log=False): + str_data = byte_data.decode('utf-8', 'replace').rstrip('\r\n') + str_data_lower = str_data.lower() + + if self.connection_state is self.STATE.PENDING: + if str_data_lower == 'capa': + self.server_connection.capa = [] + self.connection_state = self.STATE.CAPA_AWAITING_RESPONSE + super().process_data(byte_data) + + elif str_data_lower == 'auth': # a bare 'auth' command is another way to request capabilities + self.send(b'+OK\r\nPLAIN\r\n.\r\n') # no need to actually send to the server - we know what we support + + elif str_data_lower.startswith('auth plain'): + if len(str_data) > 11: # 11 = len('AUTH PLAIN ') - can have the login details either inline... + self.server_connection.username, self.server_connection.password = OAuth2Helper.decode_credentials( + str_data[11:]) + self.send_authentication_request() + else: # ...or requested separately + self.connection_state = self.STATE.AUTH_PLAIN_AWAITING_CREDENTIALS + self.censor_next_log = True + self.send(b'+ \r\n') # request details + + elif str_data_lower.startswith('user'): + self.server_connection.username = str_data[5:] # 5 = len('USER ') + self.connection_state = self.STATE.USER_AWAITING_PASS + self.send(b'+OK\r\n') # request password + + else: + super().process_data(byte_data) # some other command that we don't handle - pass directly to server + + elif self.connection_state is self.STATE.AUTH_PLAIN_AWAITING_CREDENTIALS: + if str_data == '*': # request cancelled by the client - reset state (must be a negative response) + self.connection_state = self.STATE.PENDING + self.send(b'-ERR\r\n') + else: + self.server_connection.username, self.server_connection.password = OAuth2Helper.decode_credentials( + str_data) + self.send_authentication_request() + + elif self.connection_state is self.STATE.USER_AWAITING_PASS: + if str_data_lower.startswith('pass'): + self.server_connection.password = str_data[5:] # 5 = len('PASS ') + self.send_authentication_request() + + else: + # the only valid input here is PASS (above) or QUIT + self.send(b'+OK Bye\r\n') + self.close() + + else: + super().process_data(byte_data) # some other command that we don't handle - pass directly to server + + def send_authentication_request(self): + if self.server_connection.username and self.server_connection.password: + self.connection_state = self.STATE.XOAUTH2_AWAITING_CONFIRMATION + super().process_data(b'AUTH XOAUTH2\r\n') + else: + self.server_connection.username = None + self.server_connection.password = None + self.connection_state = self.STATE.PENDING + self.send(b'-ERR Authentication failed.\r\n') + + +class SMTPOAuth2ClientConnection(OAuth2ClientConnection): + """The client side of the connection - intercept AUTH PLAIN and AUTH LOGIN commands and replace with OAuth 2.0""" + + class STATE(enum.Enum): + PENDING = 1 + EHLO_AWAITING_RESPONSE = 2 + LOCAL_STARTTLS_AWAITING_CONFIRMATION = 3 + AUTH_PLAIN_AWAITING_CREDENTIALS = 4 + AUTH_LOGIN_AWAITING_USERNAME = 5 + AUTH_LOGIN_AWAITING_PASSWORD = 6 + XOAUTH2_AWAITING_CONFIRMATION = 7 + XOAUTH2_CREDENTIALS_SENT = 8 + + def __init__(self, connection_socket, socket_map, proxy_parent, custom_configuration): + super().__init__('SMTP', connection_socket, socket_map, proxy_parent, custom_configuration) + self.connection_state = self.STATE.PENDING + + def process_data(self, byte_data, censor_server_log=False): + str_data = byte_data.decode('utf-8', 'replace').rstrip('\r\n') + str_data_lower = str_data.lower() + + # receiving any data after setting up local STARTTLS means this has succeeded + if self.connection_state is self.STATE.LOCAL_STARTTLS_AWAITING_CONFIRMATION: + Log.debug(self.info_string(), '[ Successfully negotiated SMTP client STARTTLS connection ]') + self.connection_state = self.STATE.PENDING + + # intercept EHLO so we can correct capabilities and replay after STARTTLS if needed (in server connection class) + if self.connection_state is self.STATE.PENDING: + if str_data_lower.startswith('ehlo') or str_data_lower.startswith('helo'): + self.connection_state = self.STATE.EHLO_AWAITING_RESPONSE + self.server_connection.ehlo = byte_data # save the command so we can replay later if needed (STARTTLS) + super().process_data(byte_data) # don't just go to STARTTLS - most servers require EHLO first + + # handle STARTTLS locally if enabled and a certificate is available, or reject the command + elif str_data_lower.startswith('starttls'): + if self.custom_configuration['local_starttls'] and not self.ssl_connection: + self.set_ssl_connection(True) + self.connection_state = self.STATE.LOCAL_STARTTLS_AWAITING_CONFIRMATION + self.send(b'220 Ready to start TLS\r\n') + ssl_context = ssl.create_default_context(purpose=ssl.Purpose.CLIENT_AUTH) + try: + ssl_context.load_cert_chain(certfile=self.custom_configuration['local_certificate_path'], + keyfile=self.custom_configuration['local_key_path']) + except FileNotFoundError as e: + raise FileNotFoundError('Local STARTTLS failed - unable to open `local_certificate_path` ' + 'and/or `local_key_path`') from e + + # suppress_ragged_eofs: see test_ssl.py documentation in https://github.com/python/cpython/pull/5266 + self.set_socket(ssl_context.wrap_socket(self.socket, server_side=True, suppress_ragged_eofs=True, + do_handshake_on_connect=False)) + else: + Log.error(self.info_string(), 'Client attempted to begin STARTTLS', ( + '- please either disable STARTTLS in your client when using the proxy, or set `local_starttls`' + 'and provide a `local_certificate_path` and `local_key_path`' if not self.custom_configuration[ + 'local_starttls'] else 'again after already completing the STARTTLS process')) + self.send(b'454 STARTTLS not available\r\n') + self.close() + + # intercept AUTH PLAIN and AUTH LOGIN to replace with AUTH XOAUTH2 + elif str_data_lower.startswith('auth plain'): + if len(str_data) > 11: # 11 = len('AUTH PLAIN ') - can have the login details either inline... + self.server_connection.username, self.server_connection.password = OAuth2Helper.decode_credentials( + str_data[11:]) + self.send_authentication_request() + else: # ...or requested separately + self.connection_state = self.STATE.AUTH_PLAIN_AWAITING_CREDENTIALS + self.censor_next_log = True + self.send(b'334 \r\n') # request details (note: space after response code is mandatory) + + elif str_data_lower.startswith('auth login'): + if len(str_data) > 11: # 11 = len('AUTH LOGIN ') - this method can have the username either inline... + self.decode_username_and_request_password(str_data[11:]) + else: # ...or requested separately + self.connection_state = self.STATE.AUTH_LOGIN_AWAITING_USERNAME + self.send(b'334 %s\r\n' % base64.b64encode(b'Username:')) + + else: + super().process_data(byte_data) # some other command that we don't handle - pass directly to server + + elif self.connection_state is self.STATE.AUTH_PLAIN_AWAITING_CREDENTIALS: + self.server_connection.username, self.server_connection.password = OAuth2Helper.decode_credentials( + str_data) + self.send_authentication_request() + + elif self.connection_state is self.STATE.AUTH_LOGIN_AWAITING_USERNAME: + self.decode_username_and_request_password(str_data) + + elif self.connection_state is self.STATE.AUTH_LOGIN_AWAITING_PASSWORD: + try: + self.server_connection.password = base64.b64decode(str_data).decode('utf-8') + except binascii.Error: + self.server_connection.password = '' + self.send_authentication_request() + + # some other command that we don't handle - pass directly to server + else: + super().process_data(byte_data) + + def decode_username_and_request_password(self, encoded_username): + try: + self.server_connection.username = base64.b64decode(encoded_username).decode('utf-8') + except binascii.Error: + self.server_connection.username = '' + self.connection_state = self.STATE.AUTH_LOGIN_AWAITING_PASSWORD + self.censor_next_log = True + self.send(b'334 %s\r\n' % base64.b64encode(b'Password:')) + + def send_authentication_request(self): + if self.server_connection.username and self.server_connection.password: + self.connection_state = self.STATE.XOAUTH2_AWAITING_CONFIRMATION + super().process_data(b'AUTH XOAUTH2\r\n') + else: + self.server_connection.username = None + self.server_connection.password = None + self.connection_state = self.STATE.PENDING + self.send(b'535 5.7.8 Authentication credentials invalid.\r\n') + + +class OAuth2ServerConnection(SSLAsyncoreDispatcher): + """The base server-side connection that is subclassed to handle IMAP/POP/SMTP server interaction""" + + # pylint: disable-next=too-many-positional-arguments + def __init__(self, proxy_type, connection_socket, socket_map, proxy_parent, custom_configuration): + SSLAsyncoreDispatcher.__init__(self, socket_map=socket_map) # note: establish connection later due to STARTTLS + self.receive_buffer = b'' + self.proxy_type = proxy_type + self.client_connection = None + self.proxy_parent = proxy_parent + self.local_address = proxy_parent.local_address + self.server_address = proxy_parent.server_address + self.custom_configuration = custom_configuration + self.debug_address_string = '%s-{%s}-%s' % tuple(map(Log.format_host_port, ( + connection_socket.getpeername(), connection_socket.getsockname(), self.server_address))) + + self.authenticated_username = None # used only for showing last activity in the menu + self.last_activity = 0 + + self.create_connection() + + def create_connection(self): + # resolve the given address, then create a socket and connect to each result in turn until one succeeds + # noinspection PyTypeChecker + for result in socket.getaddrinfo(*self.server_address, socket.AF_UNSPEC, socket.SOCK_STREAM): + family, socket_type, _protocol, _canonical_name, socket_address = result + try: + self.create_socket(family, socket_type) + self.connect(socket_address) + return + + except OSError as e: + self.del_channel() + if self.socket is not None: + self.socket.close() + socket_type = ' IPv4' if family == socket.AF_INET else ' IPv6' if family == socket.AF_INET6 else '' + Log.debug(self.info_string(), 'Unable to create%s socket' % socket_type, 'from getaddrinfo result', + result, '-', Log.error_string(e)) + + raise socket.gaierror(8, 'All socket creation attempts failed - unable to resolve host') + + def info_string(self): + debug_string = self.debug_address_string if Log.get_level() == logging.DEBUG else \ + Log.format_host_port(self.local_address) + account = '; %s' % self.authenticated_username if self.authenticated_username else '' + return '%s (%s%s)' % (self.proxy_type, debug_string, account) + + def handle_connect(self): + Log.debug(self.info_string(), '--> [ Client connected ]') + + # connections can either be upgraded (wrapped) after setup via the STARTTLS command, or secure from the start + if not self.custom_configuration['server_starttls']: + self.set_ssl_connection(True) + ssl_context = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH) + ssl_context.minimum_version = ssl.TLSVersion.TLSv1_2 # GitHub CodeQL issue 1 + super().set_socket(ssl_context.wrap_socket(self.socket, server_hostname=self.server_address[0], + suppress_ragged_eofs=True, do_handshake_on_connect=False)) + + def handle_read(self): + byte_data = self.recv(RECEIVE_BUFFER_SIZE) + if not byte_data: + return + + # data received before client is connected (or after client has disconnected) - ignore + if not self.client_connection: + Log.debug(self.info_string(), 'Data received without client connection - ignoring:', byte_data) + return + + # we have already authenticated - nothing to do; just pass data directly to client, ignoring overridden method + if self.client_connection.authenticated: + OAuth2ServerConnection.process_data(self, byte_data) + + # receiving data from the server while authenticated counts as activity (i.e., ignore pre-login negotiation) + if self.authenticated_username: + activity_time = time.time() // 10 # only update once every 10 or so seconds (timeago shows "just now") + if activity_time > self.last_activity: + config = AppConfig.get() + config.set(self.authenticated_username, 'last_activity', str(int(time.time()))) + self.last_activity = activity_time + + # if not authenticated, buffer incoming data and process line-by-line + else: + self.receive_buffer += byte_data + complete_lines = [] + while True: + terminator_index = self.receive_buffer.find(LINE_TERMINATOR) + if terminator_index != -1: + split_position = terminator_index + LINE_TERMINATOR_LENGTH + complete_lines.append(self.receive_buffer[:split_position]) + self.receive_buffer = self.receive_buffer[split_position:] + else: + break + + for line in complete_lines: + Log.debug(self.info_string(), ' <--', line) # (log before edits) + try: + self.process_data(line) + except AttributeError: # AttributeError("'NoneType' object has no attribute 'connection_state'"), etc + Log.info(self.info_string(), + 'Caught server exception in subclass; client connection closed before data could be sent') + self.close() + break + + def process_data(self, byte_data): + try: + self.client_connection.send(byte_data) # by default we just send everything straight to the client + except AttributeError: # AttributeError("'NoneType' object has no attribute 'send'") + Log.info(self.info_string(), 'Caught server exception; client connection closed before data could be sent') + self.close() + + def send(self, byte_data, censor_log=False): + if not self.client_connection.authenticated: # after authentication these are identical to server-side logs + Log.debug(self.info_string(), ' -->', + b'%s\r\n' % CENSOR_MESSAGE if CENSOR_CREDENTIALS and censor_log else byte_data) + return super().send(byte_data) + + def handle_error(self): + error_type, value = Log.get_last_error() + if error_type is TimeoutError and value.errno == errno.ETIMEDOUT or \ + issubclass(error_type, ConnectionError) and value.errno in [errno.ECONNRESET, errno.ECONNREFUSED] or \ + error_type is OSError and value.errno in [0, errno.ENETDOWN, errno.ENETUNREACH, errno.EHOSTDOWN, + errno.EHOSTUNREACH]: + # TimeoutError 60 = 'Operation timed out'; ConnectionError 54 = 'Connection reset by peer', 61 = 'Connection + # refused; OSError 0 = 'Error' (typically network failure), 50 = 'Network is down', 51 = 'Network is + # unreachable'; 64 = 'Host is down'; 65 = 'No route to host' + Log.info(self.info_string(), 'Caught network error (server) - is there a network connection?', + 'Error type', error_type, 'with message:', value) + self.close() + else: + super().handle_error() + + def log_info(self, message, message_type='info'): + # override to redirect error messages to our own log + if message_type not in self.ignore_log_types: + Log.info(self.info_string(), 'Caught asyncore info message (server) -', message_type, ':', message) + + def handle_close(self): + error_type, value = Log.get_last_error() + if error_type and value: + message = 'Caught connection error (server)' + if error_type is OSError and value.errno in [errno.ENOTCONN, 10057]: + # OSError 57 or 10057 = 'Socket is not connected' + message = '%s [ Client attempted to send command without waiting for server greeting ]' % message + Log.info(self.info_string(), message, '-', error_type.__name__, ':', value) + self.close() + + def close(self): + if self.client_connection: + self.client_connection.server_connection = None + with contextlib.suppress(AttributeError): + self.client_connection.close() + self.client_connection = None + with contextlib.suppress(OSError): + Log.debug(self.info_string(), '--> [ Client disconnected ]') + super().close() + + +class IMAPOAuth2ServerConnection(OAuth2ServerConnection): + """The IMAP server side - watch for the OK AUTHENTICATE response, then ignore all subsequent data""" + + # IMAP: https://tools.ietf.org/html/rfc3501 + # IMAP SASL-IR: https://tools.ietf.org/html/rfc4959 + def __init__(self, connection_socket, socket_map, proxy_parent, custom_configuration): + super().__init__('IMAP', connection_socket, socket_map, proxy_parent, custom_configuration) + + def process_data(self, byte_data): + # note: there is no reason why IMAP STARTTLS (https://tools.ietf.org/html/rfc2595) couldn't be supported here + # as with SMTP, but all well-known servers provide a non-STARTTLS variant, so left unimplemented for now + str_response = byte_data.decode('utf-8', 'replace').rstrip('\r\n') + + # if authentication succeeds (or fails), remove our proxy from the client and ignore all further communication + # don't use a regex here as the tag must match exactly; RFC 3501 specifies uppercase 'OK', so startswith is fine + if self.client_connection.authentication_tag: + if str_response.startswith('%s OK' % self.client_connection.authentication_tag): + Log.info(self.info_string(), '[ Successfully authenticated IMAP connection - releasing session ]') + self.client_connection.authenticated = True + self.client_connection.authentication_tag = None + elif str_response.startswith('+'): + # a separate request for error details (SASL additional data challenge) - the client should send b'\r\n' + pass + elif str_response.startswith('%s NO' % self.client_connection.authentication_tag): + super().process_data(byte_data) # an error occurred - just send to the client and exit + self.close() + return + + # intercept pre-auth CAPABILITY response to advertise only AUTH=PLAIN (+SASL-IR) and re-enable LOGIN if required + if IMAP_CAPABILITY_MATCHER.match(str_response): + capability = r'[!#$&\'+-\[^-z|}~]+' # https://ietf.org/rfc/rfc9051.html#name-formal-syntax + updated_response = re.sub('( AUTH=%s)+' % capability, ' AUTH=PLAIN', str_response, flags=re.IGNORECASE) + if not re.search(' AUTH=PLAIN', updated_response, re.IGNORECASE): + # cannot just replace e.g., one 'CAPABILITY ' match because IMAP4 must be first if present (RFC 1730) + updated_response = re.sub('(CAPABILITY)((?: IMAP%s)*)' % capability, r'\1\2 AUTH=PLAIN', + updated_response, count=1, flags=re.IGNORECASE) + updated_response = updated_response.replace(' AUTH=PLAIN', '', updated_response.count(' AUTH=PLAIN') - 1) + if not re.search(' SASL-IR', updated_response, re.IGNORECASE): + updated_response = updated_response.replace(' AUTH=PLAIN', ' AUTH=PLAIN SASL-IR') + updated_response = re.sub(' LOGINDISABLED', '', updated_response, count=1, flags=re.IGNORECASE) + byte_data = b'%s\r\n' % updated_response.encode('utf-8') + + super().process_data(byte_data) + + +class POPOAuth2ServerConnection(OAuth2ServerConnection): + """The POP server side - submit credentials, then watch for +OK and ignore subsequent data""" + + # POP3: https://tools.ietf.org/html/rfc1939 + # POP3 CAPA: https://tools.ietf.org/html/rfc2449 + # POP3 AUTH: https://tools.ietf.org/html/rfc1734 + # POP3 SASL: https://tools.ietf.org/html/rfc5034 + def __init__(self, connection_socket, socket_map, proxy_parent, custom_configuration): + super().__init__('POP', connection_socket, socket_map, proxy_parent, custom_configuration) + self.capa = [] + self.username = None + self.password = None + self.auth_error_result = None + + def process_data(self, byte_data): + # note: there is no reason why POP STARTTLS (https://tools.ietf.org/html/rfc2595) couldn't be supported here + # as with SMTP, but all well-known servers provide a non-STARTTLS variant, so left unimplemented for now + str_data = byte_data.decode('utf-8', 'replace').rstrip('\r\n') + + # we cache and replay the CAPA response so we can ensure it contains the right capabilities + if self.client_connection.connection_state is POPOAuth2ClientConnection.STATE.CAPA_AWAITING_RESPONSE: + if str_data.startswith('-'): # error + self.client_connection.connection_state = POPOAuth2ClientConnection.STATE.PENDING + super().process_data(byte_data) + + elif str_data == '.': # end - send our cached response, adding USER and SASL PLAIN if required + has_sasl = False + has_user = False + for capa in self.capa: + capa_lower = capa.lower() + if capa_lower.startswith('sasl'): + super().process_data(b'SASL PLAIN\r\n') + has_sasl = True + else: + if capa_lower == 'user': + has_user = True + super().process_data(b'%s\r\n' % capa.encode('utf-8')) + self.capa = [] + + if not has_sasl: + super().process_data(b'SASL PLAIN\r\n') + if not has_user: + super().process_data(b'USER\r\n') + + self.client_connection.connection_state = POPOAuth2ClientConnection.STATE.PENDING + super().process_data(byte_data) + + else: + self.capa.append(str_data) + + elif self.client_connection.connection_state is POPOAuth2ClientConnection.STATE.XOAUTH2_AWAITING_CONFIRMATION: + if str_data.startswith('+') and self.username and self.password: # '+ ' = 'please send credentials' + success, result = OAuth2Helper.get_oauth2_credentials(self.username, self.password) + if success: + # because get_oauth2_credentials blocks, the client could have disconnected, and may no-longer exist + if self.client_connection: + self.client_connection.connection_state = ( + POPOAuth2ClientConnection.STATE.XOAUTH2_CREDENTIALS_SENT) + self.send(b'%s\r\n' % OAuth2Helper.encode_oauth2_string(result), censor_log=True) + self.authenticated_username = self.username + + self.username = None + self.password = None + if not success: + # a local authentication error occurred - cancel then (on confirmation) send details to the client + self.send(b'*\r\n') # RFC 5034, Section 4 + self.auth_error_result = result + + elif str_data.startswith('-ERR') and not self.username and not self.password: + self.client_connection.connection_state = POPOAuth2ClientConnection.STATE.PENDING + error_message = self.auth_error_result if self.auth_error_result else '' + self.auth_error_result = None + super().process_data(b'-ERR Authentication failed. %s\r\n' % error_message.encode('utf-8')) + + else: + super().process_data(byte_data) # an error occurred - just send to the client and exit + self.close() + + elif self.client_connection.connection_state is POPOAuth2ClientConnection.STATE.XOAUTH2_CREDENTIALS_SENT: + if str_data.startswith('+OK'): + Log.info(self.info_string(), '[ Successfully authenticated POP connection - releasing session ]') + self.client_connection.authenticated = True + super().process_data(byte_data) + elif str_data.startswith('+'): + # a separate request for error details (SASL additional data challenge) - the client should send b'\r\n' + super().process_data(byte_data) + else: + super().process_data(byte_data) # an error occurred - just send to the client and exit + self.close() + + else: + super().process_data(byte_data) # a server->client interaction we don't handle; ignore + + +class SMTPOAuth2ServerConnection(OAuth2ServerConnection): + """The SMTP server side - setup STARTTLS, request any credentials, then watch for 235 and ignore subsequent data""" + + # SMTP: https://tools.ietf.org/html/rfc2821 + # SMTP STARTTLS: https://tools.ietf.org/html/rfc3207 + # SMTP AUTH: https://tools.ietf.org/html/rfc4954 + # SMTP LOGIN: https://datatracker.ietf.org/doc/html/draft-murchison-sasl-login-00 + class STARTTLS(enum.Enum): + PENDING = 1 + NEGOTIATING = 2 + COMPLETE = 3 + + def __init__(self, connection_socket, socket_map, proxy_parent, custom_configuration): + super().__init__('SMTP', connection_socket, socket_map, proxy_parent, custom_configuration) + self.ehlo = None + self.ehlo_response = '' + if self.custom_configuration['server_starttls']: + self.starttls_state = self.STARTTLS.PENDING + else: + self.starttls_state = self.STARTTLS.COMPLETE + + self.username = None + self.password = None + self.auth_error_result = None + + def process_data(self, byte_data): + # SMTP setup/authentication involves a little more back-and-forth than IMAP/POP as the default is STARTTLS... + str_data = byte_data.decode('utf-8', 'replace').rstrip('\r\n') + + # an EHLO request has been sent - wait for it to complete, then begin STARTTLS if required + if self.client_connection.connection_state is SMTPOAuth2ClientConnection.STATE.EHLO_AWAITING_RESPONSE: + # intercept EHLO response capabilities and replace with what we can actually do (AUTH PLAIN and LOGIN - see + # AUTH command: https://datatracker.ietf.org/doc/html/rfc4954#section-3 and corresponding formal `sasl-mech` + # syntax: https://tools.ietf.org/html/rfc4422#section-3.1); and, add/remove STARTTLS where needed + + # an error occurred in response the HELO/EHLO command - pass through to the client + if not str_data.startswith('250'): + super().process_data(byte_data) + return + + # a space after 250 signifies the final response to HELO (single line) or EHLO (multiline) + ehlo_end = str_data.split('\r\n')[-1].startswith('250 ') + updated_response = re.sub(r'250([ -])AUTH(?: [A-Z\d_-]{1,20})+', r'250\1AUTH PLAIN LOGIN', str_data, + flags=re.IGNORECASE) + updated_response = re.sub(r'250([ -])STARTTLS(?:\r\n)?', r'', updated_response, flags=re.IGNORECASE) + self.ehlo_response += '%s\r\n' % updated_response if updated_response else '' + + if ehlo_end: + self.client_connection.connection_state = SMTPOAuth2ClientConnection.STATE.PENDING + if self.starttls_state is self.STARTTLS.PENDING: + self.send(b'STARTTLS\r\n') + self.starttls_state = self.STARTTLS.NEGOTIATING + + elif self.starttls_state is self.STARTTLS.COMPLETE: + # we modify and replay the original EHLO response to the client after server STARTTLS completes + self.ehlo_response = self.ehlo_response.rstrip('\r\n') + if self.ehlo.lower().startswith(b'ehlo'): + if 'AUTH PLAIN LOGIN' not in self.ehlo_response: + self.ehlo_response += '\r\n250-AUTH PLAIN LOGIN' + if self.custom_configuration['local_starttls'] and not self.client_connection.ssl_connection: + self.ehlo_response += '\r\n250-STARTTLS' # we always remove STARTTLS; re-add if permitted + + # correct the last line where needed (250- vs 250 ) + self.ehlo_response = self.ehlo_response.replace('\r\n250 ', '\r\n250-') + self.ehlo_response = '250 '.join(self.ehlo_response.rsplit('250-', 1)) + + super().process_data(b'%s\r\n' % self.ehlo_response.encode('utf-8')) + self.ehlo = None # only clear on completion - we need to use for any repeat calls + self.ehlo_response = '' + + elif self.starttls_state is self.STARTTLS.NEGOTIATING: + if str_data.startswith('220'): + self.set_ssl_connection(True) + ssl_context = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH) + ssl_context.minimum_version = ssl.TLSVersion.TLSv1_2 # GitHub CodeQL issue 2 + super().set_socket(ssl_context.wrap_socket(self.socket, server_hostname=self.server_address[0], + suppress_ragged_eofs=True, do_handshake_on_connect=False)) + + self.starttls_state = self.STARTTLS.COMPLETE + Log.debug(self.info_string(), '[ Successfully negotiated SMTP server STARTTLS connection -', + 're-sending greeting ]') + self.client_connection.connection_state = SMTPOAuth2ClientConnection.STATE.EHLO_AWAITING_RESPONSE + self.send(self.ehlo) # re-send original EHLO/HELO to server (includes domain, so can't just be generic) + else: + super().process_data(byte_data) # an error occurred - just send to the client and exit + self.close() + + # ...then, once we have the username and password we can respond to the '334 ' response with credentials + elif self.client_connection.connection_state is SMTPOAuth2ClientConnection.STATE.XOAUTH2_AWAITING_CONFIRMATION: + if str_data.startswith('334') and self.username and self.password: # '334 ' = 'please send credentials' + success, result = OAuth2Helper.get_oauth2_credentials(self.username, self.password) + if success: + # because get_oauth2_credentials blocks, the client could have disconnected, and may no-longer exist + if self.client_connection: + self.client_connection.connection_state = ( + SMTPOAuth2ClientConnection.STATE.XOAUTH2_CREDENTIALS_SENT) + self.authenticated_username = self.username + self.send(b'%s\r\n' % OAuth2Helper.encode_oauth2_string(result), censor_log=True) + + self.username = None + self.password = None + if not success: + # a local authentication error occurred - cancel then (on confirmation) send details to the client + self.send(b'*\r\n') # RFC 4954, Section 4 + self.auth_error_result = result + + # note that RFC 4954 says that the server must respond with '501', but some (e.g., Office 365) return '535' + elif str_data.startswith('5') and not self.username and not self.password: + if len(str_data) >= 4 and str_data[3] == ' ': # responses may be multiline - wait for last part + self.client_connection.connection_state = SMTPOAuth2ClientConnection.STATE.PENDING + error_message = self.auth_error_result if self.auth_error_result else '' + self.auth_error_result = None + super().process_data( + b'535 5.7.8 Authentication credentials invalid. %s\r\n' % error_message.encode('utf-8')) + + else: + super().process_data(byte_data) # an error occurred - just send to the client and exit + self.close() + + elif self.client_connection.connection_state is SMTPOAuth2ClientConnection.STATE.XOAUTH2_CREDENTIALS_SENT: + if str_data.startswith('235'): + Log.info(self.info_string(), '[ Successfully authenticated SMTP connection - releasing session ]') + self.client_connection.authenticated = True + super().process_data(byte_data) + elif str_data.startswith('334'): + # a separate request for error details (SASL additional data challenge) - the client should send b'\r\n' + super().process_data(byte_data) + else: + super().process_data(byte_data) # an error occurred - just send to the client and exit + if len(str_data) >= 4 and str_data[3] == ' ': # responses may be multiline - wait for last part + self.close() + + else: + super().process_data(byte_data) # a server->client interaction we don't handle; ignore + + +class OAuth2Proxy(asyncore.dispatcher): + """Listen on local_address, creating an OAuth2ServerConnection + OAuth2ClientConnection for each new connection""" + + def __init__(self, proxy_type, local_address, server_address, custom_configuration): + asyncore.dispatcher.__init__(self) + self.proxy_type = proxy_type + self.local_address = local_address + self.server_address = server_address + self.custom_configuration = custom_configuration + self.ssl_connection = bool( + custom_configuration['local_certificate_path'] and custom_configuration['local_key_path']) + self.client_connections = [] + + def info_string(self): + return '%s server at %s (%s) proxying %s (%s)' % ( + self.proxy_type, Log.format_host_port(self.local_address), + 'STARTTLS' if self.custom_configuration[ + 'local_starttls'] else 'SSL/TLS' if self.ssl_connection else 'unsecured', + Log.format_host_port(self.server_address), + 'STARTTLS' if self.custom_configuration['server_starttls'] else 'SSL/TLS') + + def handle_accept(self): + Log.debug('New incoming connection to', self.info_string()) + connected_address = self.accept() + if connected_address: + self.handle_accepted(*connected_address) + else: + Log.debug('Ignoring incoming connection to', self.info_string(), '- no connection information') + + def handle_accepted(self, connection_socket, address): + if MAX_CONNECTIONS <= 0 or len(self.client_connections) < MAX_CONNECTIONS: + new_server_connection = None + try: + Log.info('Accepting new connection from', Log.format_host_port(connection_socket.getpeername()), + 'to', self.info_string()) + socket_map = {} + server_class = globals()['%sOAuth2ServerConnection' % self.proxy_type] + new_server_connection = server_class(connection_socket, socket_map, self, self.custom_configuration) + client_class = globals()['%sOAuth2ClientConnection' % self.proxy_type] + new_client_connection = client_class(connection_socket, socket_map, self, self.custom_configuration) + new_server_connection.client_connection = new_client_connection + new_client_connection.server_connection = new_server_connection + self.client_connections.append(new_client_connection) + + threading.Thread(target=OAuth2Proxy.run_server, args=(new_client_connection, socket_map), + name='EmailOAuth2Proxy-connection-%d' % address[1], daemon=True).start() + + except Exception: + connection_socket.close() + if new_server_connection: + new_server_connection.close() + raise + else: + error_text = '%s rejecting new connection above MAX_CONNECTIONS limit of %d' % ( + self.info_string(), MAX_CONNECTIONS) + Log.error(error_text) + connection_socket.send(b'%s\r\n' % self.bye_message(error_text).encode('utf-8')) + connection_socket.close() + + @staticmethod + def run_server(client, socket_map): + try: + asyncore.loop(map=socket_map) # loop for a single connection thread + except Exception as e: + if not EXITING: + # OSError 9 = 'Bad file descriptor', thrown when closing connections after network interruption + if isinstance(e, OSError) and e.errno == errno.EBADF: + Log.debug(client.info_string(), '[ Connection failed ]') + else: + Log.info(client.info_string(), 'Caught asyncore exception in thread loop:', Log.error_string(e)) + + def start(self): + Log.info('Starting', self.info_string()) + self.create_socket() + self.set_reuse_addr() + self.bind(self.local_address) + self.listen(5) + + def create_socket(self, socket_family=socket.AF_UNSPEC, socket_type=socket.SOCK_STREAM): + # listen using both IPv4 and IPv6 where possible (python 3.8 and later) + socket_family = socket.AF_INET6 if socket_family == socket.AF_UNSPEC else socket_family + if socket_family != socket.AF_INET: + try: + socket.getaddrinfo(self.local_address[0], self.local_address[1], socket_family, socket.SOCK_STREAM) + except OSError: + socket_family = socket.AF_INET + new_socket = socket.socket(socket_family, socket_type) + if socket_family == socket.AF_INET6 and getattr(socket, 'has_dualstack_ipv6', False): + new_socket.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, False) + new_socket.setblocking(False) + + # we support local connections with and without STARTTLS (currently only for SMTP), so need to either actively + # set up SSL, or wait until it is requested (note: self.ssl_connection here indicates whether the connection is + # eventually secure, either from the outset or after STARTTLS, and is required primarily for GUI icon purposes) + if self.ssl_connection and not self.custom_configuration['local_starttls']: + ssl_context = ssl.create_default_context(purpose=ssl.Purpose.CLIENT_AUTH) + try: + ssl_context.load_cert_chain(certfile=self.custom_configuration['local_certificate_path'], + keyfile=self.custom_configuration['local_key_path']) + except FileNotFoundError as e: + raise FileNotFoundError('Unable to open `local_certificate_path` and/or `local_key_path`') from e + + # suppress_ragged_eofs=True: see test_ssl.py documentation in https://github.com/python/cpython/pull/5266 + self.set_socket(ssl_context.wrap_socket(new_socket, server_side=True, suppress_ragged_eofs=True, + do_handshake_on_connect=False)) + else: + self.set_socket(new_socket) + + def remove_client(self, client): + if client in self.client_connections: # remove closed clients + self.client_connections.remove(client) + else: + Log.info('Warning:', self.info_string(), 'unable to remove orphan client connection', client) + + def bye_message(self, error_text=None): + if self.proxy_type == 'IMAP': + return '* BYE %s' % ('Server shutting down' if error_text is None else error_text) + if self.proxy_type == 'POP': + return '+OK Server signing off' if error_text is None else ('-ERR %s' % error_text) + if self.proxy_type == 'SMTP': + return '221 %s' % ('2.0.0 Service closing transmission channel' if error_text is None else error_text) + return '' + + def close_clients(self): + for connection in self.client_connections[:]: # iterate over a copy; remove (in close()) from original + connection.send(b'%s\r\n' % self.bye_message().encode('utf-8')) # try to exit gracefully + connection.close() # closes both client and server + + def stop(self): + Log.info('Stopping', self.info_string()) + self.close_clients() + self.close() + + def restart(self): + self.stop() + self.start() + + def handle_error(self): + error_type, value = Log.get_last_error() + if error_type == socket.gaierror and value.errno in [-2, 8, 11001] or \ + error_type is TimeoutError and value.errno == errno.ETIMEDOUT or \ + issubclass(error_type, ConnectionError) and value.errno in [errno.ECONNRESET, errno.ECONNREFUSED] or \ + error_type is OSError and value.errno in [0, errno.EINVAL, errno.ENETDOWN, errno.EHOSTUNREACH]: + # gaierror -2 or 8 = 'nodename nor servname provided, or not known' / 11001 = 'getaddrinfo failed' (caused + # by getpeername() failing due to no connection); TimeoutError 60 = 'Operation timed out'; ConnectionError + # 54 = 'Connection reset by peer', 61 = 'Connection refused; OSError 0 = 'Error' (local SSL failure), + # 22 = 'Invalid argument' (same cause as gaierror 11001), 50 = 'Network is down', 65 = 'No route to host' + Log.info('Caught network error in', self.info_string(), '- is there a network connection?', + 'Error type', error_type, 'with message:', value) + else: + super().handle_error() + + def log_info(self, message, message_type='info'): + # override to redirect error messages to our own log + if message_type not in self.ignore_log_types: + Log.info('Caught asyncore info message in', self.info_string(), '-', message_type, ':', message) + + def handle_close(self): + # if we encounter an unhandled exception in asyncore, handle_close() is called; restart this server + error_type, value = Log.get_last_error() + if error_type and value: + Log.info(self.info_string(), 'Caught connection error -', error_type.__name__, ':', value) + Log.info('Unexpected close of proxy connection - restarting', self.info_string()) + try: + self.restart() + except Exception as e: + Log.error('Abandoning restart of', self.info_string(), 'due to repeated exception:', Log.error_string(e)) + + +if sys.platform == 'darwin': + # noinspection PyUnresolvedReferences,PyMethodMayBeStatic,PyPep8Naming + class ProvisionalNavigationBrowserDelegate: + """Used to give pywebview the ability to navigate to unresolved local URLs (only required for macOS)""" + + # note: there is also webView_didFailProvisionalNavigation_withError_ as a broader alternative to these two + # callbacks, but using that means that window.get_current_url() returns None when the loaded handler is called + def webView_didStartProvisionalNavigation_(self, web_view, _nav): + # called when a user action (i.e., clicking our external authorisation mode submit button) redirects locally + browser_view_instance = webview.platforms.cocoa.BrowserView.get_instance( + ProvisionalNavigationBrowserDelegate.pywebview_attr, web_view) + if browser_view_instance: + browser_view_instance.loaded.set() + + def webView_didReceiveServerRedirectForProvisionalNavigation_(self, web_view, _nav): + # called when the server initiates a local redirect + browser_view_instance = webview.platforms.cocoa.BrowserView.get_instance( + ProvisionalNavigationBrowserDelegate.pywebview_attr, web_view) + if browser_view_instance: + browser_view_instance.loaded.set() + + def performKeyEquivalent_(self, event): + # modify the popup's default cmd+q behaviour to close the window rather than inadvertently exiting the proxy + if event.type() == AppKit.NSKeyDown and event.modifierFlags() & AppKit.NSCommandKeyMask and \ + event.keyCode() == 12 and self.window().firstResponder(): + self.window().performClose_(event) + return True + return False + +if sys.platform == 'darwin': + # noinspection PyUnresolvedReferences,PyUnboundLocalVariable + class UserNotificationCentreDelegate(AppKit.NSObject): + # noinspection PyPep8Naming,PyMethodMayBeStatic + def userNotificationCenter_shouldPresentNotification_(self, _notification_centre, _notification): + # the notification centre often decides that notifications shouldn't be presented; we want to override that + return AppKit.YES + + # noinspection PyPep8Naming + def userNotificationCenter_didActivateNotification_(self, _notification_centre, notification): + notification_text = notification.informativeText() + username = next((a for a in notification_text.split(' ') if '@' in a), None) + if username and 'Please authorise your account ' in notification_text: # hacky, but all we have is the text + self._click(username) + +if sys.platform == 'darwin': + # noinspection PyUnresolvedReferences,PyProtectedMember,PyUnboundLocalVariable + class RetinaIcon(pystray.Icon): + """Used to dynamically override the default pystray behaviour on macOS to support high-dpi ('retina') icons and + regeneration of the last activity time for each account every time the icon is clicked""" + + def _create_menu(self, descriptors, callbacks): + # we add a new delegate to each created menu/submenu so that we can respond to menuNeedsUpdate + menu = super()._create_menu(descriptors, callbacks) + menu.setDelegate_(self._refresh_delegate) + return menu + + def _mark_ready(self): + # in order to create the delegate *after* the NSApplication has been initialised, but only once, we override + # _mark_ready() to do so before the super() call that itself calls _create_menu() + self._refresh_delegate = self.MenuDelegate.alloc().init() + + # we add a small icon to show whether the local connection uses SSL; non-secured servers have a blank space + half_thickness = int(self._status_bar.thickness()) / 2 # half of menu bar size (see _assert_image() below) + locked_image_data = AppKit.NSData(base64.b64decode(SECURE_SERVER_ICON)) + self._refresh_delegate._locked_image = AppKit.NSImage.alloc().initWithData_(locked_image_data) + self._refresh_delegate._locked_image.setSize_((half_thickness, half_thickness)) + self._refresh_delegate._locked_image.setTemplate_(AppKit.YES) + self._refresh_delegate._unlocked_image = AppKit.NSImage.alloc().init() + self._refresh_delegate._unlocked_image.setSize_((half_thickness, half_thickness)) + + super()._mark_ready() + + # noinspection PyUnresolvedReferences + class MenuDelegate(AppKit.NSObject): + # noinspection PyMethodMayBeStatic,PyProtectedMember,PyPep8Naming + def menuNeedsUpdate_(self, sender): + # add an icon to highlight which local connections are secured (only if at least one is present), and + # update account menu items' last activity times from config cache - it would be better to delegate this + # entirely to App.create_config_menu() via update_menu(), but can't replace the menu while creating it + config_accounts = AppConfig.accounts() + menu_items = sender._itemArray() + + has_local_ssl = False # only add hints if at least one local server uses a secure connection + ssl_string = ' ' + for item in menu_items: + if 'Y_SSL ' in item.title(): + has_local_ssl = True + ssl_string = '' + break + + for item in menu_items: + item_title = item.title() + if '_SSL ' in item_title: # need to use a placeholder because we only have the title to match + if has_local_ssl: + item.setImage_(self._locked_image if 'Y_SSL ' in item_title else self._unlocked_image) + item.setTitle_(item_title.replace('N_SSL ', ssl_string).replace('Y_SSL ', ssl_string)) + continue + + for account in config_accounts: + account_title = ' %s (' % account # needed to avoid matching other menu items + if account_title in item_title: + item.setTitle_(App.get_last_activity(account)) + break + + def _assert_image(self): + # pystray does some scaling which breaks macOS retina icons - we replace that with the actual menu bar size + bytes_image = io.BytesIO() + self.icon.save(bytes_image, 'png') + data = AppKit.NSData(bytes_image.getvalue()) + self._icon_image = AppKit.NSImage.alloc().initWithData_(data) + + thickness = int(self._status_bar.thickness()) # macOS menu bar size: default = 22px, but can be scaled + self._icon_image.setSize_((thickness, thickness)) + self._icon_image.setTemplate_(AppKit.YES) # so macOS applies default shading + inverse on click + self._status_item.button().setImage_(self._icon_image) + + +class App: + """Manage the menu bar icon, server loading, authorisation and notifications, and start the main proxy thread""" + + def __init__(self, args=None): + # noinspection PyGlobalUndefined + global prompt_toolkit + global CONFIG_FILE_PATH, CACHE_STORE, EXITING + EXITING = False # needed to allow restarting when imported from parent scripts (or an interpreter) + + parser = argparse.ArgumentParser(description='%s: transparently add OAuth 2.0 support to IMAP/POP/SMTP client ' + 'applications, scripts or any other email use-cases that don\'t ' + 'support this authentication method.' % APP_NAME, add_help=False, + epilog='Full readme and guide: https://github.com/simonrob/email-oauth2-proxy') + group_gui = parser.add_argument_group(title='appearance') + group_gui.add_argument('--no-gui', action='store_false', dest='gui', + help='start the proxy without a menu bar icon (note: account authorisation requests ' + 'will fail unless a pre-authorised `--config-file` is used, or you use ' + '`--external-auth` or `--local-server-auth` and monitor log/terminal output)') + group_auth = parser.add_argument_group('authentication methods') + group_auth.add_argument('--external-auth', action='store_true', + help='handle authorisation externally: rather than intercepting `redirect_uri`, the ' + 'proxy will wait for you to paste the result into either its popup window (GUI ' + 'mode) or the terminal (no-GUI mode; requires `prompt_toolkit`)') + group_auth.add_argument('--local-server-auth', action='store_true', + help='handle authorisation by printing request URLs to the log and starting a local ' + 'web server on demand to receive responses') + group_config = parser.add_argument_group('server, account and runtime configuration') + group_config.add_argument('--config-file', default=None, + help='the full path to the proxy\'s configuration file (optional; default: `%s` in ' + 'the same directory as the proxy script)' % os.path.basename(CONFIG_FILE_PATH)) + group_config.add_argument('--cache-store', default=None, + help='the full path to a local file to use for credential caching (optional; ' + 'default: save to `--config-file`); alternatively, an external store such as a ' + 'secrets manager can be used - see readme for instructions and requirements') + group_debug = parser.add_argument_group('logging, debugging and help') + group_debug.add_argument('--log-file', default=None, + help='the full path to a file where log output should be sent (optional; default log ' + 'behaviour varies by platform - see readme for details)') + group_debug.add_argument('--debug', action='store_true', + help='enable debug mode, sending all client<->proxy<->server communication to the ' + 'proxy\'s log') + group_debug.add_argument('--version', action='version', version='%s %s' % (APP_NAME, __version__), + help='show the proxy\'s version string and exit') + group_debug.add_argument('-h', '--help', action='help', help='show this help message and exit') + + self.args = parser.parse_args(args) + + Log.initialise(self.args.log_file) + self.toggle_debug(self.args.debug, log_message=False) + + if self.args.config_file: + CONFIG_FILE_PATH = CACHE_STORE = self.args.config_file + if self.args.cache_store: + CACHE_STORE = self.args.cache_store + + self.proxies = [] + self.authorisation_requests = [] + + self.web_view_started = False + self.macos_web_view_queue = queue.Queue() # authentication window events (macOS only) + + self.init_platforms() + + if not self.args.gui and self.args.external_auth: + try: + # prompt_toolkit is a relatively recent dependency addition that is only required in no-GUI external + # authorisation mode, but may not be present if only the proxy script itself has been updated + import prompt_toolkit + except ImportError: + Log.error('Unable to load prompt_toolkit, which is a requirement when using `--external-auth` in', + '`--no-gui` mode. Please run `python -m pip install -r requirements-core.txt`') + self.exit(None) + return + + if self.args.gui and len(MISSING_GUI_REQUIREMENTS) > 0: + Log.error('Unable to load all GUI requirements:', MISSING_GUI_REQUIREMENTS, '- did you mean to run in', + '`--no-gui` mode? If not, please run `python -m pip install -r requirements-gui.txt` or install', + 'from PyPI with GUI requirements included: `python -m pip install "emailproxy[gui]"`') + self.exit(None) + return + + if self.args.gui: + self.icon = self.create_icon() + try: + self.icon.run(self.post_create) + except NotImplementedError: + Log.error('Unable to initialise icon - did you mean to run in `--no-gui` mode?') + self.exit(None) + else: + self.icon = None + self.post_create(None) + + # PyAttributeOutsideInit inspection suppressed because init_platforms() is itself called from __init__() + # noinspection PyUnresolvedReferences,PyAttributeOutsideInit + def init_platforms(self): + if sys.platform == 'darwin' and self.args.gui: + if len(MISSING_GUI_REQUIREMENTS) > 0: + return # skip - we will exit anyway due to missing requirements (with a more helpful error message) + + # hide dock icon (but not LSBackgroundOnly as we need input via webview) + info = AppKit.NSBundle.mainBundle().infoDictionary() + info['LSUIElement'] = '1' + + # need to delegate and override to show both "authenticate now" and "authentication success" notifications + self.macos_user_notification_centre_delegate = UserNotificationCentreDelegate.alloc().init() + setattr(self.macos_user_notification_centre_delegate, '_click', lambda m: self.authorise_account(None, m)) + + # any launchctl plist changes need reloading, but this must be scheduled on exit (see discussion below) + self.macos_unload_plist_on_exit = False + + # track shutdown and network loss events and exit or close proxy connections appropriately + # note: no need to explicitly remove this observer after OS X 10.11 (https://developer.apple.com/library + # /archive/releasenotes/Foundation/RN-FoundationOlderNotes/index.html#10_11NotificationCenter) + notification_listener = 'macos_nsworkspace_notification_listener:' + notification_centre = AppKit.NSWorkspace.sharedWorkspace().notificationCenter() + notification_centre.addObserver_selector_name_object_(self, notification_listener, + AppKit.NSWorkspaceWillPowerOffNotification, None) + notification_centre.addObserver_selector_name_object_(self, notification_listener, + SystemConfiguration.SCNetworkReachabilityRef, None) + + # we use a zero/blank address because we only care about general availability rather than a specific host + # see reachabilityForInternetConnection: https://developer.apple.com/library/archive/samplecode/Reachability + # use of SCNetworkReachabilityRef is a little hacky (requires a callback name) but it works + address = ('', 0) + post_reachability_update = notification_centre.postNotificationName_object_ + self.macos_reachability_target = SystemConfiguration.SCNetworkReachabilityCreateWithAddress(None, address) + SystemConfiguration.SCNetworkReachabilitySetCallback(self.macos_reachability_target, + lambda _target, flags, _info: post_reachability_update( + SystemConfiguration.SCNetworkReachabilityRef, + flags), address) + success, result = SystemConfiguration.SCNetworkReachabilityGetFlags(self.macos_reachability_target, None) + if success: + post_reachability_update(SystemConfiguration.SCNetworkReachabilityRef, result) # update initial state + SystemConfiguration.SCNetworkReachabilityScheduleWithRunLoop(self.macos_reachability_target, + SystemConfiguration.CFRunLoopGetCurrent(), + SystemConfiguration.kCFRunLoopCommonModes) + + # on macOS, catching SIGINT/SIGTERM/SIGQUIT/SIGHUP while in pystray's main loop needs a Mach signal handler + PyObjCTools.MachSignals.signal(signal.SIGINT, lambda _signum: self.exit(self.icon)) + PyObjCTools.MachSignals.signal(signal.SIGTERM, lambda _signum: self.exit(self.icon)) + PyObjCTools.MachSignals.signal(signal.SIGQUIT, lambda _signum: self.exit(self.icon)) + PyObjCTools.MachSignals.signal(signal.SIGHUP, lambda _signum: self.load_and_start_servers(self.icon)) + PyObjCTools.MachSignals.signal(signal.SIGUSR1, lambda _: self.toggle_debug(Log.get_level() == logging.INFO)) + + else: + # for other platforms, or in no-GUI mode, just try to exit gracefully if SIGINT/SIGTERM/SIGQUIT is received + signal.signal(signal.SIGINT, lambda _signum, _frame: self.exit(self.icon)) + signal.signal(signal.SIGTERM, lambda _signum, _frame: self.exit(self.icon)) + if hasattr(signal, 'SIGQUIT'): # not all signals exist on all platforms (e.g., Windows) + signal.signal(signal.SIGQUIT, lambda _signum, _frame: self.exit(self.icon)) + if hasattr(signal, 'SIGHUP'): + # allow config file reloading without having to stop/start - e.g.: pkill -SIGHUP -f emailproxy.py + # (we don't use linux_restart() here as it exits then uses nohup to restart, which may not be desirable) + signal.signal(signal.SIGHUP, lambda _signum, _frame: self.load_and_start_servers(self.icon)) + if hasattr(signal, 'SIGUSR1'): + # use SIGUSR1 as a toggle for debug mode (e.g.: pkill -USR1 -f emailproxy.py) - please note that the + # proxy's handling of this signal may change in future if other actions are seen as more suitable + signal.signal(signal.SIGUSR1, lambda _signum, _fr: self.toggle_debug(Log.get_level() == logging.INFO)) + + # certificates are not imported automatically when packaged using pyinstaller/nuitka - we need certifi + if FROZEN_PACKAGE: + if ssl.get_default_verify_paths().cafile is None and 'SSL_CERT_FILE' not in os.environ: + try: + import certifi + os.environ['SSL_CERT_FILE'] = certifi.where() + Log.info('Running in a packaged/frozen environment - imported SSL certificates from `certifi`') + except ImportError: + Log.info('Unable to find `certifi` in a packaged/frozen environment - SSL connections may fail') + + # noinspection PyUnresolvedReferences,PyAttributeOutsideInit + def macos_nsworkspace_notification_listener_(self, notification): + notification_name = notification.name() + if notification_name == SystemConfiguration.SCNetworkReachabilityRef: + flags = notification.object() + if flags & SystemConfiguration.kSCNetworkReachabilityFlagsReachable == 0: + Log.info('Received network unreachable notification - closing existing proxy connections') + for proxy in self.proxies: + proxy.close_clients() + else: + Log.debug('Received network reachable notification - status:', flags) + elif notification_name == AppKit.NSWorkspaceWillPowerOffNotification: + Log.info('Received power off notification; exiting', APP_NAME) + self.exit(self.icon) + + # noinspection PyDeprecation + def create_icon(self): + # fix pystray <= 0.19.4 incompatibility with PIL 10.0.0+; resolved in 0.19.5 and later via pystray PR #147 + pystray_version = packaging.version.Version(importlib_metadata.version('pystray')) + pillow_version = packaging.version.Version(importlib_metadata.version('pillow')) + if pystray_version <= packaging.version.Version('0.19.4') and \ + pillow_version >= packaging.version.Version('10.0.0'): + Image.ANTIALIAS = Image.LANCZOS if hasattr(Image, 'LANCZOS') else Image.Resampling.LANCZOS + + icon_class = RetinaIcon if sys.platform == 'darwin' else pystray.Icon + return icon_class(APP_NAME, App.get_image(), APP_NAME, menu=pystray.Menu( + pystray.MenuItem('Servers and accounts', pystray.Menu(self.create_config_menu)), + pystray.MenuItem('Authorise account', pystray.Menu(self.create_authorisation_menu)), + pystray.Menu.SEPARATOR, + pystray.MenuItem('Start at login', self.toggle_start_at_login, checked=self.started_at_login), + pystray.MenuItem('Debug mode', lambda _, item: self.toggle_debug(not item.checked), + checked=lambda _: Log.get_level() == logging.DEBUG), + pystray.Menu.SEPARATOR, + pystray.MenuItem('Quit %s' % APP_NAME, self.exit))) + + @staticmethod + def get_image(): + # we use an icon font for better multiplatform compatibility and icon size flexibility + icon_colour = 'white' # see below: colour is handled differently per-platform + icon_character = 'e' + icon_background_width = 44 + icon_background_height = 44 + icon_width = 40 # to allow for padding between icon and background image size + + # the colour value is irrelevant on macOS - we configure the menu bar icon as a template to get the platform's + # colours - but on Windows (and in future potentially Linux) we need to set based on the current theme type + if sys.platform == 'win32': + import winreg + try: + key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, + r'Software\Microsoft\Windows\CurrentVersion\Themes\Personalize') + icon_colour = 'black' if winreg.QueryValueEx(key, 'SystemUsesLightTheme')[0] else 'white' + except FileNotFoundError: + pass + + # find the largest font size that will let us draw the icon within the available width + minimum_font_size = 1 + maximum_font_size = 255 + font, font_width, font_height = App.get_icon_size(icon_character, minimum_font_size) + while maximum_font_size - minimum_font_size > 1: + current_font_size = round((minimum_font_size + maximum_font_size) / 2) # ImageFont only supports integers + font, font_width, font_height = App.get_icon_size(icon_character, current_font_size) + if font_width > icon_width: + maximum_font_size = current_font_size + elif font_width < icon_width: + minimum_font_size = current_font_size + else: + break + if font_width > icon_width: # because we have to round font sizes we need one final check for oversize width + font, font_width, font_height = App.get_icon_size(icon_character, minimum_font_size) + + icon_image = Image.new('RGBA', (icon_background_width, icon_background_height)) + draw = ImageDraw.Draw(icon_image) + icon_x = (icon_background_width - font_width) / 2 + icon_y = (icon_background_height - font_height) / 2 + draw.text((icon_x, icon_y), icon_character, font=font, fill=icon_colour) + + return icon_image + + @staticmethod + def get_icon_size(text, font_size): + font = ImageFont.truetype(io.BytesIO(zlib.decompress(base64.b64decode(APP_ICON))), size=font_size) + + # pillow's getsize method was deprecated in 9.2.0 (see docs for PIL.ImageFont.ImageFont.getsize) + if packaging.version.Version(importlib_metadata.version('pillow')) < packaging.version.Version('9.2.0'): + # noinspection PyUnresolvedReferences + font_width, font_height = font.getsize(text) + return font, font_width, font_height + + _left, _top, right, bottom = font.getbbox(text) + return font, right, bottom + + def create_config_menu(self): + items = [] + if len(self.proxies) <= 0: + # note that we don't actually allow no servers when loading the config, so no need to generate a menu + return items # (avoids creating and then immediately regenerating the menu when servers are loaded) + + for server_type in ['IMAP', 'POP', 'SMTP']: + items.extend(App.get_config_menu_servers(self.proxies, server_type)) + + config_accounts = AppConfig.accounts() + items.append(pystray.MenuItem('Accounts (+ last authenticated activity):', None, enabled=False)) + if len(config_accounts) <= 0: + items.append(pystray.MenuItem(' No accounts configured', None, enabled=False)) + else: + catch_all_enabled = AppConfig.get_global('allow_catch_all_accounts', fallback=False) + catch_all_accounts = [] + for account in config_accounts: + if account.startswith('@') and catch_all_enabled: + catch_all_accounts.append(account) + else: + items.append(pystray.MenuItem(App.get_last_activity(account), None, enabled=False)) + if len(catch_all_accounts) > 0: + items.append(pystray.Menu.SEPARATOR) + items.append(pystray.MenuItem('Catch-all accounts:', None, enabled=False)) + for account in catch_all_accounts: + items.append(pystray.MenuItem(' %s' % account, None, enabled=False)) + if sys.platform != 'darwin': + items.append(pystray.MenuItem(' Refresh activity data', self.icon.update_menu)) + items.append(pystray.Menu.SEPARATOR) + + items.append(pystray.MenuItem('Edit configuration file...', lambda: self.system_open(CONFIG_FILE_PATH))) + + # asyncore sockets on Linux have a shutdown delay (the time.sleep() call in asyncore.poll), which means we can't + # easily reload the server configuration without exiting the script and relying on daemon threads to be stopped + items.append(pystray.MenuItem('Reload configuration file', self.linux_restart if sys.platform.startswith( + 'linux') else self.load_and_start_servers)) + return items + + @staticmethod + def get_config_menu_servers(proxies, server_type): + items = [] + heading_appended = False + for proxy in filter(lambda p: p.proxy_type == server_type, proxies): + if not heading_appended: + items.append(pystray.MenuItem('%s servers:' % server_type, None, enabled=False)) + heading_appended = True + items.append(pystray.MenuItem('%s %s ➝ %s' % ( + ('Y_SSL' if proxy.ssl_connection else 'N_SSL') if sys.platform == 'darwin' else '', + Log.format_host_port(proxy.local_address), Log.format_host_port(proxy.server_address)), + None, enabled=False)) + if heading_appended: + items.append(pystray.Menu.SEPARATOR) + return items + + @staticmethod + def get_last_activity(account): + config = AppConfig.get() + last_sync = config.getint(account, 'last_activity', fallback=None) + if last_sync: + formatted_sync_time = timeago.format(datetime.datetime.fromtimestamp(last_sync), datetime.datetime.now(), + 'en_short') + else: + formatted_sync_time = 'never' + return ' %s (%s)' % (account, formatted_sync_time) + + @staticmethod + def system_open(path): + AppConfig.save() # so we are always editing the most recent version of the file + if sys.platform == 'darwin': + result = subprocess.call(['open', path]) + if result != 0: # no default editor found for this file type; open as a text file + subprocess.call(['open', '-t', path]) + elif sys.platform == 'win32': + os.startfile(path) + elif sys.platform.startswith('linux'): + subprocess.call(['xdg-open', path]) + else: + pass # nothing we can do + + def create_authorisation_menu(self): + items = [] + if len(self.authorisation_requests) <= 0: + items.append(pystray.MenuItem('No pending authorisation requests', None, enabled=False)) + else: + usernames = [] + for request in self.authorisation_requests: + if request['username'] not in usernames: + items.append(pystray.MenuItem(request['username'], self.authorise_account)) + usernames.append(request['username']) + items.append(pystray.Menu.SEPARATOR) + items.append(pystray.MenuItem('External authorisation mode', self.toggle_external_auth, + checked=lambda _: self.args.external_auth)) + return items + + def toggle_external_auth(self): + self.args.external_auth = not self.args.external_auth + if self.started_at_login(None): + self.toggle_start_at_login(self.icon, True) # update launch command to preserve external auth preference + + def authorise_account(self, _, item): + for request in self.authorisation_requests: + if str(item) == request['username']: # use str(item) because item.text() hangs + if not self.web_view_started: + # pywebview on macOS needs start() to be called only once, so we use a dummy window to keep it open + # Windows is the opposite - the macOS technique freezes the tray icon; Linux is fine either way + # (we also set pywebview debug mode to match our own mode because copy/paste via keyboard shortcuts + # can be unreliable with 'mshtml'; and, python virtual environments sometimes break keyboard entry + # entirely on macOS - debug mode works around this in both cases via the right-click context menu) + self.create_authorisation_window(request) + if sys.platform == 'darwin': + webview.start(self.handle_authorisation_windows, debug=Log.get_level() == logging.DEBUG) + self.web_view_started = True # note: not set for other platforms so we start() every time + else: + # on Windows, most pywebview engine options return None for get_current_url() on pages created + # using 'html=' even on redirection to an actual URL; 'mshtml', though archaic, does work + forced_gui = 'mshtml' if sys.platform == 'win32' and self.args.external_auth else None + webview.start(gui=forced_gui, debug=Log.get_level() == logging.DEBUG) + else: + self.macos_web_view_queue.put(request) # future requests need to use the same thread + return + self.notify(APP_NAME, 'There are no pending authorisation requests') + + def create_authorisation_window(self, request): + # note that the webview title *must* contain the email address/username as it is used to confirm success + window_title = 'Authorise your account: %s' % request['username'] + if request['user_code']: + window_title += ' with code: %s' % request['user_code'] + + if self.args.external_auth: + if request['user_code']: + auth_page = EXTERNAL_AUTH_DAG_HTML % ( + request['username'], *[request['permission_url']] * 3, *[request['user_code']] * 2) + else: + auth_page = EXTERNAL_AUTH_HTML % ( + request['username'], *[request['permission_url']] * 3, APP_NAME, request['redirect_uri']) + authorisation_window = webview.create_window(window_title, html=auth_page, on_top=True, text_select=True) + else: + authorisation_window = webview.create_window(window_title, request['permission_url'], on_top=True) + setattr(authorisation_window, 'get_title', lambda window: window.title) # add missing get_title method + + # pywebview 3.6+ moved window events to a separate namespace in a non-backwards-compatible way + pywebview_version = packaging.version.Version(importlib_metadata.version('pywebview')) + # the version zero check is due to a bug in the Ubuntu 24.04 python-pywebview package - see GitHub #242 + if packaging.version.Version('0') < pywebview_version < packaging.version.Version('3.6'): + # noinspection PyUnresolvedReferences + authorisation_window.loaded += self.authorisation_window_loaded + else: + authorisation_window.events.loaded += self.authorisation_window_loaded + + def handle_authorisation_windows(self): + if sys.platform != 'darwin': + return + + # on macOS we need to add extra webview functions to detect when redirection starts, because otherwise the + # pywebview window can get into a state in which http://localhost navigation, rather than failing, just hangs + # noinspection PyUnresolvedReferences + import webview.platforms.cocoa + pywebview_version = packaging.version.Version(importlib_metadata.version('pywebview')) + ProvisionalNavigationBrowserDelegate.pywebview_attr = 'webkit' if pywebview_version < packaging.version.Version( + '5.3') else 'webview' + setattr(webview.platforms.cocoa.BrowserView.BrowserDelegate, 'webView_didStartProvisionalNavigation_', + ProvisionalNavigationBrowserDelegate.webView_didStartProvisionalNavigation_) + setattr(webview.platforms.cocoa.BrowserView.BrowserDelegate, 'webView_didReceiveServerRedirectForProvisional' + 'Navigation_', + ProvisionalNavigationBrowserDelegate.webView_didReceiveServerRedirectForProvisionalNavigation_) + setattr(webview.platforms.cocoa.BrowserView.WebKitHost, 'performKeyEquivalent_', + ProvisionalNavigationBrowserDelegate.performKeyEquivalent_) + + # also needed only on macOS because otherwise closing the last remaining webview window exits the application + dummy_window = webview.create_window('%s hidden (dummy) window' % APP_NAME, html='', hidden=True) + dummy_window.hide() # hidden=True (above) doesn't seem to work in all cases + + while True: + data = self.macos_web_view_queue.get() # note: blocking call + if data is QUEUE_SENTINEL: # app is closing + break + self.create_authorisation_window(data) + + def authorisation_window_loaded(self): + for window in webview.windows[:]: # iterate over a copy; remove (in destroy()) from original + if not hasattr(window, 'get_title'): + continue # skip dummy window + + url = window.get_current_url() + # noinspection PyUnresolvedReferences + username = next((a for a in window.get_title(window).split(' ') if '@' in a), None) + if not url or not username: # see note in create_authorisation_window: title *must* match username format + continue # skip any invalid windows + + # respond to both the original request and any duplicates in the list + completed_request = None + for request in self.authorisation_requests[:]: # iterate over a copy; remove from original + if request['username'] == username and OAuth2Helper.match_redirect_uri(request['redirect_uri'], url): + Log.info('Returning authorisation request result for', request['username']) + if not request['user_code']: # the device authorisation grant flow does not require a response + RESPONSE_QUEUE.put( + {'permission_url': request['permission_url'], 'response_url': url, 'username': username}) + self.authorisation_requests.remove(request) + completed_request = request + else: + Log.debug('Waiting for URL matching `redirect_uri`; following browser redirection to', + '%s/[...]' % urllib.parse.urlparse(url).hostname) + + if completed_request is None: + continue # no requests processed for this window - nothing to do yet + + # the DAG flow will not normally have a matching `redirect_uri`; wait for users to close the window manually + if not completed_request['user_code']: + window.destroy() + self.icon.update_menu() + + # note that in this part of the interaction we don't actually check the *use* of the authorisation code, + # but just whether it was successfully acquired - if there is an error in the subsequent access/refresh + # token request then we still send an 'authentication completed' notification here, but in the background + # we close the connection with a failure message and re-request authorisation next time the client + # interacts, which may potentially lead to repeated and conflicting (and confusing) notifications - improve? + self.notify(APP_NAME, 'Authentication completed for %s' % completed_request['username']) + if len(self.authorisation_requests) > 0: + self.notify(APP_NAME, 'Please authorise your account %s from the menu' % self.authorisation_requests[0][ + 'username']) + + def toggle_start_at_login(self, icon, force_rewrite=False): + # we reuse this function to force-overwrite the startup file when changing the external auth option, but pystray + # verifies actions have a maximum of two parameters (_assert_action()), so we must use 'item' and check its type + recreate_login_file = False if isinstance(force_rewrite, pystray.MenuItem) else force_rewrite + + start_command = self.get_script_start_command(quote_args=sys.platform != 'darwin') # plistlib handles quoting + + if sys.platform == 'darwin': + if recreate_login_file or not PLIST_FILE_PATH.exists(): + # need to create and load the plist + plist = { + 'Label': APP_PACKAGE, + 'RunAtLoad': True + } + else: + # just toggle the disabled value rather than loading/unloading, so we don't need to restart the proxy + with open(PLIST_FILE_PATH, mode='rb') as plist_file: + plist = plistlib.load(plist_file) + plist['Disabled'] = True if 'Disabled' not in plist else not plist['Disabled'] + + plist['Program'] = start_command[0] + # noinspection PyTypeChecker + plist['ProgramArguments'] = start_command + + os.makedirs(PLIST_FILE_PATH.parent, exist_ok=True) + with open(PLIST_FILE_PATH, mode='wb') as plist_file: + plistlib.dump(plist, plist_file) + + # if loading, need to exit so we're not running twice (also exits the terminal instance for convenience) + if not self.macos_launchctl('list'): + self.exit(icon, restart_callback=lambda: self.macos_launchctl('load')) + elif recreate_login_file: + # Launch Agents need to be unloaded and reloaded to reflect changes in their plist file, but we can't + # do this ourselves because 1) unloading exits the agent; and, 2) we can't launch a completely separate + # subprocess (see man launchd.plist) - instead, we schedule the unload action when we next exit, because + # this is likely to be caused by a system restart, and unloaded Launch Agents still run at startup (only + # an issue if calling `launchctl start` after exiting, which will error until the Agent is reloaded) + # noinspection PyAttributeOutsideInit + self.macos_unload_plist_on_exit = True + Log.info('Updating', PLIST_FILE_PATH, 'requires unloading and reloading; scheduling on next exit') + + elif sys.platform == 'win32': + if recreate_login_file or not CMD_FILE_PATH.exists(): + windows_start_command = 'start "" %s' % ' '.join(start_command) # first quoted start arg = window title + + os.makedirs(CMD_FILE_PATH.parent, exist_ok=True) + with open(CMD_FILE_PATH, mode='w', encoding='utf-8') as cmd_file: + cmd_file.write(windows_start_command) + + # on Windows we don't have a service to run, but it is still useful to exit the terminal instance + if sys.stdin and sys.stdin.isatty() and not recreate_login_file: + self.exit(icon, restart_callback=lambda: subprocess.call(windows_start_command, shell=True)) + else: + os.remove(CMD_FILE_PATH) + + elif sys.platform.startswith('linux'): + # see https://github.com/simonrob/email-oauth2-proxy/issues/2#issuecomment-839713677 for systemctl option + if recreate_login_file or not AUTOSTART_FILE_PATH.exists(): + xdg_autostart = { + 'Type': 'Application', + 'Name': APP_NAME, + 'Exec': ' '.join(start_command), + 'NoDisplay': 'true' + } + + os.makedirs(AUTOSTART_FILE_PATH.parent, exist_ok=True) + with open(AUTOSTART_FILE_PATH, mode='w', encoding='utf-8') as desktop_file: + desktop_file.write('[Desktop Entry]\n') + for key, value in xdg_autostart.items(): + desktop_file.write('%s=%s\n' % (key, value)) + + # like on Windows we don't have a service to run, but it is still useful to exit the terminal instance + if sys.stdin and sys.stdin.isatty() and not recreate_login_file: + AppConfig.save() # because linux_restart needs to unload to prevent saving on exit + self.linux_restart(icon) + else: + os.remove(AUTOSTART_FILE_PATH) + + else: + pass # nothing we can do + + def get_script_start_command(self, quote_args=True): + python_command = sys.executable + if sys.platform == 'win32': + # pythonw to avoid a terminal when background launching on Windows + python_command = 'pythonw.exe'.join(python_command.rsplit('python.exe', 1)) + + script_command = [python_command] + if not FROZEN_PACKAGE: # no need for the script path if using pyinstaller/nuitka + if __package__ is not None: + script_command.extend(['-m', APP_SHORT_NAME]) + else: + script_command.append(os.path.realpath(__file__)) + + # preserve any arguments - note that some are configurable in the GUI, so sys.argv may not be their actual state + script_command.extend(arg for arg in sys.argv[1:] if arg not in ('--debug', '--external-auth')) + if Log.get_level() == logging.DEBUG: + script_command.append('--debug') + if self.args.external_auth: + script_command.append('--external-auth') + + return ['"%s"' % arg.replace('"', r'\"') if quote_args and ' ' in arg else arg for arg in script_command] + + def linux_restart(self, icon): + # Linux restarting is separate because it is used for reloading the configuration file as well as start at login + AppConfig.unload() # so that we don't overwrite the just-updated file when exiting + command = ' '.join(self.get_script_start_command()) + self.exit(icon, restart_callback=lambda: subprocess.call('nohup %s /dev/null 2>&1 &' % command, + shell=True)) + + @staticmethod + def macos_launchctl(command): + # this used to use the python launchctl package, but it has a bug (github.com/andrewp-as-is/values.py/pull/2) + # in a sub-package, so we reproduce just the core features - supported commands are 'list', 'load' and 'unload' + proxy_command = APP_PACKAGE if command == 'list' else PLIST_FILE_PATH + try: + output = subprocess.check_output(['/bin/launchctl', command, proxy_command], stderr=subprocess.STDOUT) + except subprocess.CalledProcessError: + return False + + if output and command != 'list': + return False # load/unload gives no output unless unsuccessful (return code is always 0 regardless) + return True + + @staticmethod + def started_at_login(_): + # note: menu state will be stale if changed externally, but clicking menu items forces a refresh + if sys.platform == 'darwin': + if PLIST_FILE_PATH.exists(): + if App.macos_launchctl('list'): + with open(PLIST_FILE_PATH, mode='rb') as plist_file: + plist = plistlib.load(plist_file) + if 'Disabled' in plist: + return not plist['Disabled'] + return True # job is loaded and is not disabled + + elif sys.platform == 'win32': + return CMD_FILE_PATH.exists() # we assume that the file's contents are correct + + elif sys.platform.startswith('linux'): + return AUTOSTART_FILE_PATH.exists() # we assume that the file's contents are correct + + return False + + def toggle_debug(self, enable_debug_mode, log_message=True): + Log.set_level(logging.DEBUG if enable_debug_mode else logging.INFO) + if log_message: + Log.info('Setting debug mode:', Log.get_level() == logging.DEBUG) + if hasattr(self, 'icon') and self.icon: + self.icon.update_menu() + + # noinspection PyUnresolvedReferences + def notify(self, title, text): + if self.icon: + if sys.platform == 'darwin': # prefer native notifications over the osascript approach + user_notification = AppKit.NSUserNotification.alloc().init() + user_notification.setTitle_(title) + user_notification.setInformativeText_(text) + notification_centre = AppKit.NSUserNotificationCenter.defaultUserNotificationCenter() + + # noinspection PyBroadException + try: + notification_centre.setDelegate_(self.macos_user_notification_centre_delegate) + notification_centre.deliverNotification_(user_notification) + except Exception: + for replacement in (('\\', r'\\'), ('"', r'\"')): # osascript approach requires sanitisation + text = text.replace(*replacement) + title = title.replace(*replacement) + subprocess.call(['osascript', '-e', 'display notification "%s" with title "%s"' % (text, title)]) + + elif self.icon.HAS_NOTIFICATION: + self.icon.remove_notification() + self.icon.notify('%s: %s' % (title, text)) + + Log.info(text) # duplicate to log for, e.g., local server auth mode when GUI is present + else: + Log.info(text) + + def stop_servers(self): + global RESPONSE_QUEUE + RESPONSE_QUEUE.put(QUEUE_SENTINEL) # watchers use a local reference so won't re-insert into the new queue + RESPONSE_QUEUE = queue.Queue() # recreate so existing queue closes watchers but we don't have to wait here + while True: + try: + REQUEST_QUEUE.get(block=False) # remove any pending requests (unlikely any exist, but safest) + except queue.Empty: + break + for proxy in self.proxies: + with contextlib.suppress(Exception): + proxy.stop() + self.proxies = [] + self.authorisation_requests = [] # these requests are no-longer valid + + def load_and_start_servers(self, icon=None, reload=True): + # we allow reloading, so must first stop any existing servers + self.stop_servers() + Log.info('Initialising', APP_NAME, + '(version %s)%s' % (__version__, ' in debug mode' if Log.get_level() == logging.DEBUG else ''), + 'from config file', CONFIG_FILE_PATH) + if reload: + AppConfig.unload() + + config_parse_error = False + try: + config = AppConfig.get() + servers = AppConfig.servers() + except configparser.Error as e: + Log.error('Unable to load configuration file:', e) + config_parse_error = True + servers = [] + + # load server types and configurations + server_load_error = False + server_start_error = False + for section in servers: + match = CONFIG_SERVER_MATCHER.match(section) + server_type = match.group('type') + + # noinspection PyUnboundLocalVariable + local_address = config.get(section, 'local_address', fallback='::') + str_local_port = match.group('port') + local_port = -1 + try: + local_port = int(str_local_port) + if local_port <= 0 or local_port > 65535: + raise ValueError + except ValueError: + Log.error('Error: invalid value', str_local_port, 'for local server port in section', match.string) + server_load_error = True + + server_address = config.get(section, 'server_address', fallback=None) + server_port = config.getint(section, 'server_port', fallback=-1) + if server_port <= 0 or server_port > 65535: + Log.error('Error: invalid value', server_port, 'for remote server port in section', match.string) + server_load_error = True + + custom_configuration = { + 'server_starttls': False, + 'local_starttls': False, + 'local_certificate_path': config.get(section, 'local_certificate_path', fallback=None), + 'local_key_path': config.get(section, 'local_key_path', fallback=None) + } + if server_type == 'SMTP': + # initially the STARTTLS setting was remote server only, and hence named just `starttls` - support this + legacy_starttls = config.getboolean(section, 'starttls', fallback=False) + custom_configuration['server_starttls'] = config.getboolean(section, 'server_starttls', + fallback=legacy_starttls) + + custom_configuration['local_starttls'] = config.getboolean(section, 'local_starttls', fallback=False) + if custom_configuration['local_starttls'] and not (custom_configuration['local_certificate_path'] and + custom_configuration['local_key_path']): + Log.error('Error: you have set `local_starttls` but did not provide both ' + '`local_certificate_path` and `local_key_path` values in section', match.string) + server_load_error = True + + if not server_address: # all other values are checked, regex matched or have a fallback above + Log.error('Error: remote server address is missing in section', match.string) + server_load_error = True + + if not server_load_error: + new_proxy = OAuth2Proxy(server_type, (local_address, local_port), (server_address, server_port), + custom_configuration) + try: + new_proxy.start() + self.proxies.append(new_proxy) + except Exception as e: + Log.error('Error: unable to start', match.string, 'server:', Log.error_string(e)) + server_start_error = True + + if config_parse_error or server_start_error or server_load_error or len(self.proxies) <= 0: + if server_start_error: + Log.error('Abandoning setup as one or more servers failed to start - is the proxy already running?') + else: + if not os.path.exists(CONFIG_FILE_PATH): + Log.error(APP_NAME, 'config file not found - see https://github.com/simonrob/email-oauth2-proxy', + 'for full documentation and example configurations to help get started') + error_text = 'Invalid' if len(servers) > 0 else 'Unparsable' if config_parse_error else 'No' + Log.error(error_text, 'server configuration(s) found in', CONFIG_FILE_PATH, '- exiting') + self.notify(APP_NAME, error_text + ' server configuration(s) found. ' + + 'Please verify your account and server details in %s' % CONFIG_FILE_PATH) + AppConfig.unload() # so we don't overwrite the invalid file with a blank configuration + self.exit(icon) + return False + + if icon: + icon.update_menu() # force refresh the menu to show running proxy servers + + threading.Thread(target=App.run_proxy, name='EmailOAuth2Proxy-main', daemon=True).start() + Log.info('Initialised', APP_NAME, '- listening for authentication requests. Connect your email client to begin') + return True + + @staticmethod + def terminal_external_auth_input(prompt_session, prompt_stop_event, data): + with contextlib.suppress(Exception): # cancel any other prompts; thrown if there are none to cancel + # noinspection PyUnresolvedReferences + prompt_toolkit.application.current.get_app().exit(exception=EOFError) + time.sleep(1) # seems to be needed to allow prompt_toolkit to clean up between prompts + + # noinspection PyUnresolvedReferences + with prompt_toolkit.patch_stdout.patch_stdout(): + open_time = 0 + response_url = None + Log.info('Please visit the following URL to authenticate account %s: %s' % ( + data['username'], data['permission_url'])) + # noinspection PyUnresolvedReferences + style = prompt_toolkit.styles.Style.from_dict({'url': 'underline'}) + prompt = [('', '\nCopy+paste or press [↵ Return] to visit the following URL and authenticate account %s: ' % + data['username']), ('class:url', data['permission_url']), ('', ' then paste here the full '), + ('', 'post-authentication URL from the browser\'s address bar (it should start with %s): ' % + data['redirect_uri'])] + while True: + try: + response_url = prompt_session.prompt(prompt, style=style) + except (KeyboardInterrupt, EOFError): + break + if not response_url: + if time.time() - open_time > 1: # don't open many windows on key repeats + App.system_open(data['permission_url']) + open_time = time.time() + else: + break + + prompt_stop_event.set() # cancel the timeout thread + + result = {'permission_url': data['permission_url'], 'username': data['username']} + if response_url: + Log.debug('No-GUI external auth mode: returning response', response_url) + result['response_url'] = response_url + else: + Log.debug('No-GUI external auth mode: no response provided; cancelling authorisation request') + result['expired'] = True + RESPONSE_QUEUE.put(result) + + @staticmethod + def terminal_external_auth_timeout(prompt_session, prompt_stop_event): + prompt_time = 0 + while prompt_time < AUTHENTICATION_TIMEOUT and not prompt_stop_event.is_set(): + time.sleep(1) + prompt_time += 1 + + if not prompt_stop_event.is_set(): + with contextlib.suppress(Exception): # thrown if the prompt session has already exited + prompt_session.app.exit(exception=EOFError) + time.sleep(1) # seems to be needed to allow prompt_toolkit to clean up between prompts + + def terminal_external_auth_prompt(self, data): + # noinspection PyUnresolvedReferences + prompt_session = prompt_toolkit.PromptSession() + prompt_stop_event = threading.Event() + threading.Thread(target=self.terminal_external_auth_input, args=(prompt_session, prompt_stop_event, data), + daemon=True).start() + threading.Thread(target=self.terminal_external_auth_timeout, args=(prompt_session, prompt_stop_event), + daemon=True).start() + + def post_create(self, icon): + if EXITING: + return # to handle launch in pystray 'dummy' mode without --no-gui option (partial initialisation failure) + + if icon: + icon.visible = True + + if not self.load_and_start_servers(icon, reload=False): + return + + while True: + data = REQUEST_QUEUE.get() # note: blocking call + if data is QUEUE_SENTINEL: # app is closing + break + if data is MENU_UPDATE: + if icon: + icon.update_menu() + continue + if not data['expired']: + Log.info('Authorisation request received for', data['username'], + '(local server auth mode)' if self.args.local_server_auth else '(external auth mode)' if + self.args.external_auth else '(interactive mode)') + + user_code_notification = None + if data['user_code']: + RESPONSE_QUEUE.put(data) # device flow does not require a user response; here we only notify + user_code_notification = 'Visit %s and use code %s' % (data['permission_url'], data['user_code']) + + if self.args.local_server_auth: + self.notify(APP_NAME, 'Local server auth mode: please authorise a request for account %s' % + data['username']) + if user_code_notification: + # note: local server auth mode doesn't make any sense with the device flow as it is poll-based, + # so here we notify and return the request as normal, but don't actually start the local server + self.notify(APP_NAME, user_code_notification) + else: + data['local_server_auth'] = True + RESPONSE_QUEUE.put(data) # local server auth is handled by the client/server connections + + elif self.args.external_auth and not self.args.gui: + can_auth_interactively = sys.stdin and sys.stdin.isatty() + if can_auth_interactively: + self.notify(APP_NAME, 'No-GUI external auth mode: please authorise a request for account ' + '%s' % data['username']) + if user_code_notification: + self.notify(APP_NAME, user_code_notification) + else: + self.terminal_external_auth_prompt(data) + if not can_auth_interactively: + Log.error('Not running interactively; unable to handle no-GUI external auth request') + + elif icon: + self.authorisation_requests.append(data) + icon.update_menu() # force refresh the menu + self.notify(APP_NAME, 'Please authorise your account %s from the menu' % data['username']) + + else: + for request in self.authorisation_requests[:]: # iterate over a copy; remove from original + if request['permission_url'] == data['permission_url']: + self.authorisation_requests.remove(request) + break # we could have multiple simultaneous requests, some not yet expired + + @staticmethod + def run_proxy(): + while not EXITING: + error_count = 0 + try: + # loop for main proxy servers, accepting requests and starting connection threads + # note: we need to make sure there are always proxy servers started when run_proxy is called (i.e., must + # exit on server start failure), otherwise this will throw an error every time and loop indefinitely + asyncore.loop() + except Exception as e: + if not EXITING and not (isinstance(e, OSError) and e.errno == errno.EBADF): + Log.info('Caught asyncore exception in main loop; attempting to continue:', Log.error_string(e)) + error_count += 1 + time.sleep(error_count) + + def exit(self, icon, restart_callback=None): + Log.info('Stopping', APP_NAME) + global EXITING + EXITING = True + + AppConfig.save() + + # attribute existence check is needed here and below because we may exit before init_platforms() has run + if sys.platform == 'darwin' and self.args.gui and hasattr(self, 'macos_reachability_target'): + # noinspection PyUnresolvedReferences + SystemConfiguration.SCNetworkReachabilityUnscheduleFromRunLoop(self.macos_reachability_target, + SystemConfiguration.CFRunLoopGetCurrent(), + SystemConfiguration.kCFRunLoopDefaultMode) + + REQUEST_QUEUE.put(QUEUE_SENTINEL) + RESPONSE_QUEUE.put(QUEUE_SENTINEL) + + if self.web_view_started: + self.macos_web_view_queue.put(QUEUE_SENTINEL) + for window in webview.windows[:]: # iterate over a copy; remove (in destroy()) from original + window.show() + window.destroy() + + for proxy in self.proxies: # no need to copy - proxies are never removed, we just restart them on error + with contextlib.suppress(Exception): + proxy.stop() + + if icon: + # work around a pystray issue with removing the macOS status bar icon when started from a parent script + if sys.platform == 'darwin': + # noinspection PyProtectedMember + icon._status_item.button().setImage_(None) + icon.stop() + + # for the 'Start at login' option we need a callback to restart the script the first time this preference is + # configured (macOS) or every time (other platforms) - note that just as in toggle_start_at_login(), pystray + # verifies that actions have a maximum of two parameters, so we must override the 'item' one but check its type + if restart_callback and not isinstance(restart_callback, pystray.MenuItem): + Log.info('Restarted', APP_NAME, 'as a background task') + restart_callback() + + # macOS Launch Agents need reloading when changed; unloading exits immediately so this must be our final action + if sys.platform == 'darwin' and self.args.gui and ( + hasattr(self, 'macos_unload_plist_on_exit') and self.macos_unload_plist_on_exit): + self.macos_launchctl('unload') + + +if __name__ == '__main__': + App() diff --git a/pyproject.toml b/pyproject.toml new file mode 100644 index 0000000..992e6f4 --- /dev/null +++ b/pyproject.toml @@ -0,0 +1,45 @@ +[build-system] +requires = ["setuptools>=62.6.0"] +build-backend = "setuptools.build_meta" + +[project] +name = "emailproxy" +authors = [ + { name = "Simon Robinson", email = "simon@robinson.ac" } +] +description = "Transparently add OAuth 2.0 support to IMAP/POP/SMTP clients that don't support this authentication method." +readme = { file = "README.md", content-type = "text/markdown" } +license = { text = "Apache License 2.0" } +requires-python = ">=3.7" +classifiers = [ + "Operating System :: OS Independent", + "Operating System :: MacOS", + "Operating System :: Microsoft :: Windows", + "Operating System :: POSIX :: Linux", + "Programming Language :: Python", + "Topic :: Communications :: Email", + "Topic :: Communications :: Email :: Mail Transport Agents", + "Topic :: Communications :: Email :: Post-Office", + "Topic :: Communications :: Email :: Post-Office :: IMAP", + "Topic :: Communications :: Email :: Post-Office :: POP3", + "Development Status :: 6 - Mature", + "License :: OSI Approved :: Apache Software License" +] +dynamic = ["dependencies", "optional-dependencies", "version"] + +[tool.setuptools] +py-modules = ["emailproxy"] # ignore other folders in the root directory (note that some (such as "tests") *cannot* be ignored in the .tar.gz sdist without a MANIFEST.in) + +[project.scripts] +emailproxy = "emailproxy:App" + +[project.urls] # shown in alphabetical order on PyPI, and there is no way to put a "Homepage" link first as with the setup.py approach (but see https://github.com/pypi/warehouse/blob/main/warehouse/templates/packaging/detail.html) +"Documentation" = "https://github.com/simonrob/email-oauth2-proxy#email-oauth-20-proxy" +"Release Notes" = "https://github.com/simonrob/email-oauth2-proxy/releases" +"Report Issues" = "https://github.com/simonrob/email-oauth2-proxy/issues" +"Source Code" = "https://github.com/simonrob/email-oauth2-proxy" + +[tool.setuptools.dynamic] +dependencies = { file = ["requirements-core.txt"] } +optional-dependencies.gui = { file = ["requirements-gui.txt"] } +version = { attr = "emailproxy.__package_version__" } diff --git a/requirements-core.txt b/requirements-core.txt new file mode 100644 index 0000000..d62ab1f --- /dev/null +++ b/requirements-core.txt @@ -0,0 +1,18 @@ +# this file contains the proxy's core dependencies beyond inbuilt python packages +# note that to use the proxy with only these requirements you *must* pass the `--no-gui` option when starting - see the +# script's readme for further details + +# 2.2 or later required for MultiFernet support +cryptography>=2.2 + +# provide the previously standard library module `asyncore`, removed in Python 3.12 (https://peps.python.org/pep-0594/) +pyasyncore; python_version >= '3.12' + +# macOS only: output to unified logging +pyoslog>=0.3.0; sys_platform == 'darwin' + +# required only if using the --external-auth option in --no-gui mode +prompt_toolkit + +# required only if using JWT certificate credentials (O365) +pyjwt>=2.4 diff --git a/requirements-gui.txt b/requirements-gui.txt new file mode 100644 index 0000000..dc48b84 --- /dev/null +++ b/requirements-gui.txt @@ -0,0 +1,20 @@ +# the standard way to install the proxy and dependencies is `python -m pip install emailproxy` (i.e., direct from PyPI) +# to install requirements directly, use: `python -m pip install -r requirements-core.txt -r requirements-gui.txt` + +importlib_metadata; python_version < '3.8' # to get dependency versions (available in stdlib from 3.8 onwards) +packaging # for dependency version comparisons +pillow # to create the menu bar icon image from a TTF icon +timeago # for displaying the last authenticated activity hint + +# force pystray version with dummy GUI fix for headless deployments (https://github.com/moses-palmer/pystray/issues/118) +pystray>=0.19.4 + +# force pywebview 4.2.1+ to fix Windows issue with PyInstaller/pythonw (https://github.com/r0x0r/pywebview/issues/1086) +# and a macOS pre-Mojave crash when opening browser windows (https://github.com/r0x0r/pywebview/pull/1047), plus a +# missing macOS dependency issue introduced in 4.1 (https://github.com/r0x0r/pywebview/pull/1154) - note that we could +# do, e.g., platform_release < '18' to allow Linux platforms more flexibility, but that seems over-the-top +pywebview>=4.2.1 + +# macOS: improve menu bar interaction, provide native notifications and handle system events +pyobjc-framework-Cocoa; sys_platform == 'darwin' +pyobjc-framework-SystemConfiguration; sys_platform == 'darwin'