diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/encodings/idna.py | 42 | ||||
| -rw-r--r-- | Lib/test/test_codecs.py | 6 |
2 files changed, 31 insertions, 17 deletions
diff --git a/Lib/encodings/idna.py b/Lib/encodings/idna.py index ea40585..5396047 100644 --- a/Lib/encodings/idna.py +++ b/Lib/encodings/idna.py @@ -39,23 +39,21 @@ def nameprep(label): # Check bidi RandAL = [stringprep.in_table_d1(x) for x in label] - for c in RandAL: - if c: - # There is a RandAL char in the string. Must perform further - # tests: - # 1) The characters in section 5.8 MUST be prohibited. - # This is table C.8, which was already checked - # 2) If a string contains any RandALCat character, the string - # MUST NOT contain any LCat character. - if any(stringprep.in_table_d2(x) for x in label): - raise UnicodeError("Violation of BIDI requirement 2") - - # 3) If a string contains any RandALCat character, a - # RandALCat character MUST be the first character of the - # string, and a RandALCat character MUST be the last - # character of the string. - if not RandAL[0] or not RandAL[-1]: - raise UnicodeError("Violation of BIDI requirement 3") + if any(RandAL): + # There is a RandAL char in the string. Must perform further + # tests: + # 1) The characters in section 5.8 MUST be prohibited. + # This is table C.8, which was already checked + # 2) If a string contains any RandALCat character, the string + # MUST NOT contain any LCat character. + if any(stringprep.in_table_d2(x) for x in label): + raise UnicodeError("Violation of BIDI requirement 2") + # 3) If a string contains any RandALCat character, a + # RandALCat character MUST be the first character of the + # string, and a RandALCat character MUST be the last + # character of the string. + if not RandAL[0] or not RandAL[-1]: + raise UnicodeError("Violation of BIDI requirement 3") return label @@ -103,6 +101,16 @@ def ToASCII(label): raise UnicodeError("label empty or too long") def ToUnicode(label): + if len(label) > 1024: + # Protection from https://github.com/python/cpython/issues/98433. + # https://datatracker.ietf.org/doc/html/rfc5894#section-6 + # doesn't specify a label size limit prior to NAMEPREP. But having + # one makes practical sense. + # This leaves ample room for nameprep() to remove Nothing characters + # per https://www.rfc-editor.org/rfc/rfc3454#section-3.1 while still + # preventing us from wasting time decoding a big thing that'll just + # hit the actual <= 63 length limit in Step 6. + raise UnicodeError("label way too long") # Step 1: Check for ASCII if isinstance(label, bytes): pure_ascii = True diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py index 32a704f..e3add0c 100644 --- a/Lib/test/test_codecs.py +++ b/Lib/test/test_codecs.py @@ -1552,6 +1552,12 @@ class IDNACodecTest(unittest.TestCase): self.assertEqual("pyth\xf6n.org".encode("idna"), b"xn--pythn-mua.org") self.assertEqual("pyth\xf6n.org.".encode("idna"), b"xn--pythn-mua.org.") + def test_builtin_decode_length_limit(self): + with self.assertRaisesRegex(UnicodeError, "way too long"): + (b"xn--016c"+b"a"*1100).decode("idna") + with self.assertRaisesRegex(UnicodeError, "too long"): + (b"xn--016c"+b"a"*70).decode("idna") + def test_stream(self): r = codecs.getreader("idna")(io.BytesIO(b"abc")) r.read(3) |