GH-1206: validate decompressed length in Lz4CompressionCodec#1207
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lidavidm
approved these changes
Jul 5, 2026
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What's Changed
Lz4CompressionCodec.doDecompresssizes the output buffer to the bytes it actually decompressed, but setswriterIndexto the length taken from the untrusted 8-byte prefix. A buffer whose prefix claims more than the real output leaves the returnedArrowBufwith awriterIndexpast its capacity, and consumers then read off-heap memory beyond the allocation. This adds the actual-vs-claimed length check the ZSTD codec already does, so a mismatch throws instead of producing an over-long buffer.Closes #1206.