From: Steve Dower Date: Wed, 17 Apr 2024 18:32:47 +0000 (+0100) Subject: gh-114539: Clarify implicit launching of shells by subprocess (GH-117996) X-Git-Tag: v3.13.0b1~366 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a4b44d39cd6941cc03590fee7538776728bdfd0a;p=thirdparty%2FPython%2Fcpython.git gh-114539: Clarify implicit launching of shells by subprocess (GH-117996) --- diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index 49194b82b4ce..1cd233173e85 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -754,8 +754,8 @@ Exceptions defined in this module all inherit from :exc:`SubprocessError`. Security Considerations ----------------------- -Unlike some other popen functions, this implementation will never -implicitly call a system shell. This means that all characters, +Unlike some other popen functions, this library will not +implicitly choose to call a system shell. This means that all characters, including shell metacharacters, can safely be passed to child processes. If the shell is invoked explicitly, via ``shell=True``, it is the application's responsibility to ensure that all whitespace and metacharacters are @@ -764,6 +764,14 @@ quoted appropriately to avoid vulnerabilities. On :ref:`some platforms `, it is possible to use :func:`shlex.quote` for this escaping. +On Windows, batch files (:file:`*.bat` or :file:`*.cmd`) may be launched by the +operating system in a system shell regardless of the arguments passed to this +library. This could result in arguments being parsed according to shell rules, +but without any escaping added by Python. If you are intentionally launching a +batch file with arguments from untrusted sources, consider passing +``shell=True`` to allow Python to escape special characters. See :gh:`114539` +for additional discussion. + Popen Objects -------------