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Do not validate snappy xerial header version and compat fields #2483

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Merged
merged 1 commit into from
Feb 17, 2025
Merged

Do not validate snappy xerial header version and compat fields #2483

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11 changes: 9 additions & 2 deletions kafka/codec.py
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Original file line number Diff line number Diff line change
Expand Up @@ -193,8 +193,15 @@ def _detect_xerial_stream(payload):
"""

if len(payload) > 16:
header = struct.unpack('!' + _XERIAL_V1_FORMAT, bytes(payload)[:16])
return header == _XERIAL_V1_HEADER
magic = struct.unpack('!' + _XERIAL_V1_FORMAT[:8], bytes(payload)[:8])
version, compat = struct.unpack('!' + _XERIAL_V1_FORMAT[8:], bytes(payload)[8:16])
# Until there is more than one way to do xerial blocking, the version + compat
# fields can be ignored. Also some producers (i.e., redpanda) are known to
# incorrectly encode these as little-endian, and that causes us to fail decoding
# when we otherwise would have succeeded.
# See https://github.com/dpkp/kafka-python/issues/2414
if magic == _XERIAL_V1_HEADER[:8]:
return True
return False


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2 changes: 2 additions & 0 deletions test/test_codec.py
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Expand Up @@ -39,12 +39,14 @@ def test_snappy_detect_xerial():
_detect_xerial_stream = kafka1.codec._detect_xerial_stream

header = b'\x82SNAPPY\x00\x00\x00\x00\x01\x00\x00\x00\x01Some extra bytes'
redpanda_header = b'\x82SNAPPY\x00\x01\x00\x00\x00\x01\x00\x00\x00Some extra bytes'
false_header = b'\x01SNAPPY\x00\x00\x00\x01\x00\x00\x00\x01'
default_snappy = snappy_encode(b'foobar' * 50)
random_snappy = snappy_encode(b'SNAPPY' * 50, xerial_compatible=False)
short_data = b'\x01\x02\x03\x04'

assert _detect_xerial_stream(header) is True
assert _detect_xerial_stream(redpanda_header) is True
assert _detect_xerial_stream(b'') is False
assert _detect_xerial_stream(b'\x00') is False
assert _detect_xerial_stream(false_header) is False
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