https://github.com/python/cpython/commit/905aab60f72ec5aa9183ec0b74b5eda8f9ca188d commit: 905aab60f72ec5aa9183ec0b74b5eda8f9ca188d branch: main author: Jelle Zijlstra <[email protected]> committer: JelleZijlstra <[email protected]> date: 2026-10-20T10:23:14-07:00 summary:
gh-159739: Bound encoding-name lookahead in surrogatepass (#159785) Co-authored-by: Jelle Zijlstra <[email protected]> files: A Misc/NEWS.d/next/Library/2026-10-19-20-38-17.gh-issue-159739.243aa8.rst M Lib/test/test_codeccallbacks.py M Python/codecs.c diff --git a/Lib/test/test_codeccallbacks.py b/Lib/test/test_codeccallbacks.py index 65d54d1004d647..7ab8eea0142520 100644 --- a/Lib/test/test_codeccallbacks.py +++ b/Lib/test/test_codeccallbacks.py @@ -755,6 +755,18 @@ def test_badandgoodsurrogatepassexceptions(self): (s[:1], 1 + n) ) + def test_surrogatepass_truncated_encoding_name(self): + handler = codecs.lookup_error('surrogatepass') + for width in (16, 32): + encoding = f'utf-{width}-' + data = (0xd800).to_bytes(width // 8, 'little') + for exc in (UnicodeEncodeError(encoding, '\ud800', 0, 1, 'test'), + UnicodeDecodeError(encoding, data, 0, len(data), 'test')): + with self.subTest(encoding=encoding, error=type(exc).__name__): + with self.assertRaises(type(exc)) as cm: + handler(exc) + self.assertIs(cm.exception, exc) + def test_badhandlerresults(self): results = ( 42, "foo", (1,2,3), ("foo", 1, 3), ("foo", None), ("foo",), ("foo", 1, 3), ("foo", None), ("foo",) ) encs = ("ascii", "latin-1", "iso-8859-1", "iso-8859-15") diff --git a/Misc/NEWS.d/next/Library/2026-10-19-20-38-17.gh-issue-159739.243aa8.rst b/Misc/NEWS.d/next/Library/2026-10-19-20-38-17.gh-issue-159739.243aa8.rst new file mode 100644 index 00000000000000..a9452184e7838f --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-10-19-20-38-17.gh-issue-159739.243aa8.rst @@ -0,0 +1,2 @@ +Avoid reading past the end of an encoding name when the ``surrogatepass`` +error handler receives a truncated UTF-16 or UTF-32 name. diff --git a/Python/codecs.c b/Python/codecs.c index 84a0589c8e8317..8a4d99bdd924fa 100644 --- a/Python/codecs.c +++ b/Python/codecs.c @@ -1173,7 +1173,8 @@ get_standard_encoding_impl(const char *encoding, int *bytelength) } if (*encoding == '-' || *encoding == '_' ) encoding++; - if (Py_TOLOWER(encoding[1]) == 'e' && encoding[2] == '\0') { + if (encoding[0] != '\0' && + Py_TOLOWER(encoding[1]) == 'e' && encoding[2] == '\0') { if (Py_TOLOWER(encoding[0]) == 'b') return ENC_UTF16BE; if (Py_TOLOWER(encoding[0]) == 'l') @@ -1192,7 +1193,8 @@ get_standard_encoding_impl(const char *encoding, int *bytelength) } if (*encoding == '-' || *encoding == '_' ) encoding++; - if (Py_TOLOWER(encoding[1]) == 'e' && encoding[2] == '\0') { + if (encoding[0] != '\0' && + Py_TOLOWER(encoding[1]) == 'e' && encoding[2] == '\0') { if (Py_TOLOWER(encoding[0]) == 'b') return ENC_UTF32BE; if (Py_TOLOWER(encoding[0]) == 'l') _______________________________________________ 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]
