https://github.com/python/cpython/commit/2f840249550e082dc351743f474ba56da10478d2 commit: 2f840249550e082dc351743f474ba56da10478d2 branch: 3.10 author: Gregory P. Smith <[email protected]> committer: sethmlarson <[email protected]> date: 2026-01-20T22:51:43Z summary:
[3.10] gh-143916: Reject control characters in wsgiref.headers.Headers gh-143916: Reject control characters in wsgiref.headers.Headers (GH-143917) * Add 'test.support' fixture for C0 control characters * gh-143916: Reject control characters in wsgiref.headers.Headers (cherry picked from commit f7fceed79ca1bceae8dbe5ba5bc8928564da7211) (cherry picked from commit 22e4d55285cee52bc4dbe061324e5f30bd4dee58) Co-authored-by: Seth Michael Larson <[email protected]> files: A Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst M Lib/test/support/__init__.py M Lib/test/test_wsgiref.py M Lib/wsgiref/headers.py diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py index 0d3b9634f10248..d0492fe1914343 100644 --- a/Lib/test/support/__init__.py +++ b/Lib/test/support/__init__.py @@ -2157,3 +2157,10 @@ def adjust_int_max_str_digits(max_digits): yield finally: sys.set_int_max_str_digits(current) + + +def control_characters_c0() -> list[str]: + """Returns a list of C0 control characters as strings. + C0 control characters defined as the byte range 0x00-0x1F, and 0x7F. + """ + return [chr(c) for c in range(0x00, 0x20)] + ["\x7F"] diff --git a/Lib/test/test_wsgiref.py b/Lib/test/test_wsgiref.py index 42094f467731d4..01ca51ba458587 100644 --- a/Lib/test/test_wsgiref.py +++ b/Lib/test/test_wsgiref.py @@ -1,6 +1,6 @@ from unittest import mock from test import support -from test.support import socket_helper +from test.support import socket_helper, control_characters_c0 from test.support import warnings_helper from test.test_httpservers import NoLogRequestHandler from unittest import TestCase @@ -527,6 +527,16 @@ def testExtras(self): '\r\n' ) + def testRaisesControlCharacters(self): + headers = Headers() + for c0 in control_characters_c0(): + self.assertRaises(ValueError, headers.__setitem__, f"key{c0}", "val") + self.assertRaises(ValueError, headers.__setitem__, "key", f"val{c0}") + self.assertRaises(ValueError, headers.add_header, f"key{c0}", "val", param="param") + self.assertRaises(ValueError, headers.add_header, "key", f"val{c0}", param="param") + self.assertRaises(ValueError, headers.add_header, "key", "val", param=f"param{c0}") + + class ErrorHandler(BaseCGIHandler): """Simple handler subclass for testing BaseHandler""" diff --git a/Lib/wsgiref/headers.py b/Lib/wsgiref/headers.py index fab851c5a44430..fd98e85d75492b 100644 --- a/Lib/wsgiref/headers.py +++ b/Lib/wsgiref/headers.py @@ -9,6 +9,7 @@ # existence of which force quoting of the parameter value. import re tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]') +_control_chars_re = re.compile(r'[\x00-\x1F\x7F]') def _formatparam(param, value=None, quote=1): """Convenience function to format and return a key=value pair. @@ -41,6 +42,8 @@ def __init__(self, headers=None): def _convert_string_type(self, value): """Convert/check value type.""" if type(value) is str: + if _control_chars_re.search(value): + raise ValueError("Control characters not allowed in headers") return value raise AssertionError("Header names/values must be" " of type str (got {0})".format(repr(value))) diff --git a/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst b/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst new file mode 100644 index 00000000000000..44bd0b27059f94 --- /dev/null +++ b/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst @@ -0,0 +1,2 @@ +Reject C0 control characters within wsgiref.headers.Headers fields, values, +and parameters. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
