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gh-68966: Document mailcap shell injection vulnerability #92024

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gh-68966: Document mailcap shell injection vulnerability #92024

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964a082
gh-68966: Document mailcap shell injection vulnerability
vstinner Apr 28, 2022
042f0cf
Mention the vulnerability in Security Considerations page
vstinner Apr 28, 2022
a48f663
Shell command can be injected in any argument
vstinner Apr 28, 2022
7cfbbfc
Fix typo
vstinner Apr 28, 2022
aa6beb5
Update Doc/library/mailcap.rst
vstinner Apr 29, 2022
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10 changes: 10 additions & 0 deletions Doc/library/mailcap.rst
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Expand Up @@ -26,6 +26,16 @@ The mailcap format is documented in :rfc:`1524`, "A User Agent Configuration
Mechanism For Multimedia Mail Format Information", but is not an internet
standard. However, mailcap files are supported on most Unix systems.

.. _ailcap-shell-injection:

.. warning::

The Python implementation is vulnerable to shell command injection. By
design, the mailcap format uses shell commands. The caller is responsible to
validate the filename. The caller can create temporary filename, using
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It's not only about the filename. The MIME type and parameter list need to be validated as well.
Also, how should they be validated? That's not clear.

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You're right, I rephrased the warning.

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"The caller is responsible to validate and sanitize input arguments."

:func:`tempfile.NamedTemporaryFile` or :func:`tempfile.mkstemp` for example,
to get a safe filename.


.. function:: findmatch(caps, MIMEtype, key='view', filename='/dev/null', plist=[])

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1 change: 1 addition & 0 deletions Doc/library/security_warnings.rst
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Expand Up @@ -17,6 +17,7 @@ The following modules have specific security considerations:
basic security checks
* :mod:`logging`: :ref:`Logging configuration uses eval()
<logging-eval-security>`
* :mod:`mailcap`: :ref:`Shell command injection <mailcap-shell-injection>`
* :mod:`multiprocessing`: :ref:`Connection.recv() uses pickle
<multiprocessing-recv-pickle-security>`
* :mod:`pickle`: :ref:`Restricting globals in pickle <pickle-restrict>`
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