check snappy block length before crc trailer in decode_snappy#3807
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dxbjavid wants to merge 1 commit into
Open
check snappy block length before crc trailer in decode_snappy#3807dxbjavid wants to merge 1 commit into
dxbjavid wants to merge 1 commit into
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decode_snappy in lang/c/src/codec.c takes the block length straight from the container file, where file_read_block_count only rejects negative values, so a snappy block of 1 to 3 bytes reaches it and the len-4 used for snappy_uncompressed_length, snappy_uncompress and the trailing CRC memcmp underflows to a huge size_t and reads out of bounds. The C++ reader in DataFile.cc already refuses len < 4 before the same subtraction, so add the matching check here.