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No longer reject dictionaries with literals maxSymbolValue < 255

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We already have logic in our Huffman encoder to validate Huffman tables with missing symbols.
We use this for higher compression levels to re-use the previous blocks statistics, or when the dictionaries table has zero-weighted symbols.
This check was leftover as an oversight from before we added validation for Huffman tables.

I validated that the `dictionary_loader` fuzzer has coverage of every line in the `ZSTD_loadCEntropy()` function to validate that it is correctly testing this function.
This commit is contained in:
Nick Terrell
2023-08-22 13:22:35 -04:00
committed by Nick Terrell
parent 9662fe1683
commit bd02c9be6e
1 changed files with 1 additions and 2 deletions
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lib/compress/zstd_compress.c
+1 -2
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@@ -4904,11 +4904,10 @@ size_t ZSTD_loadCEntropy(ZSTD_compressedBlockState_t* bs, void* workspace,
/* We only set the loaded table as valid if it contains all non-zero /* We only set the loaded table as valid if it contains all non-zero
* weights. Otherwise, we set it to check */ * weights. Otherwise, we set it to check */
if (!hasZeroWeights) if (!hasZeroWeights && maxSymbolValue == 255)
bs->entropy.huf.repeatMode = HUF_repeat_valid; bs->entropy.huf.repeatMode = HUF_repeat_valid;
RETURN_ERROR_IF(HUF_isError(hufHeaderSize), dictionary_corrupted, ""); RETURN_ERROR_IF(HUF_isError(hufHeaderSize), dictionary_corrupted, "");
RETURN_ERROR_IF(maxSymbolValue < 255, dictionary_corrupted, "");
dictPtr += hufHeaderSize; dictPtr += hufHeaderSize;
} }