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[fuzz] Only set HUF_repeat_valid if loaded table has all non-zero weights (#1898)

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Fixes a fuzz issue where dictionary_round_trip failed because the compressor was generating corrupt files thanks to zero weights in the table.

* Only setting loaded dict huf table to valid on non-zero

* Adding hasNoZeroWeights test to fse tables

* Forbiding nbBits != 0 when weight == 0

* Reverting the last commit

* Setting table log to 0 when weight == 0

* Small (invalid) zero weight dict test

* Small (valid) zero weight dict test

* Initializing repeatMode vars to check before zero check

* Removing FSE changes to seperate pr

* Reverting accidentally changed file

* Negating bool, using unsigned, optimization nit
This commit is contained in:
Bimba Shrestha
2019-11-26 12:24:19 -08:00
committed by Nick Terrell
parent d6e0a44576
commit a3a3c62b81
5 changed files with 32 additions and 7 deletions
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lib/compress/huf_compress.c
+4 -2
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@@ -169,7 +169,7 @@ size_t HUF_writeCTable (void* dst, size_t maxDstSize,
}
size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize)
size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned* hasZeroWeights)
{
BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1]; /* init not required, even though some static analyzer may complain */
U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1]; /* large enough for values from 0 to 16 */
@@ -192,9 +192,11 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void
} }
/* fill nbBits */
*hasZeroWeights = 0;
{ U32 n; for (n=0; n<nbSymbols; n++) {
const U32 w = huffWeight[n];
CTable[n].nbBits = (BYTE)(tableLog + 1 - w);
*hasZeroWeights |= (w == 0);
CTable[n].nbBits = (BYTE)(tableLog + 1 - w) & -(w != 0);
} }
/* fill val */