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Fix buffer overrun in ZSTD_loadEntropy()

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The table log set by `FSE_readNCount()` was not checked in
`ZSTD_loadEntropy()`.  This caused `FSE_buildDTable(dctx->MLTable, ...)`
to overwrite the beginning of `dctx->hufTable`.

The benchmarks look good, there is no obvious performance regression:

  > ./zstds/zstd.opt.0 -i10 -b1 -e5 ~/bench/silesia.tar
   1#silesia.tar       : 211988480 ->  73656930 (2.878), 268.2 MB/s , 701.0 MB/s
   2#silesia.tar       : 211988480 ->  70162842 (3.021), 199.5 MB/s , 666.9 MB/s
   3#silesia.tar       : 211988480 ->  66997986 (3.164), 154.9 MB/s , 655.6 MB/s
   4#silesia.tar       : 211988480 ->  66002591 (3.212), 128.9 MB/s , 648.4 MB/s
   5#silesia.tar       : 211988480 ->  65008480 (3.261),  98.4 MB/s , 633.4 MB/s

  > ./zstds/zstd.opt.2 -i10 -b1 -e5 ~/bench/silesia.tar
   1#silesia.tar       : 211988480 ->  73656930 (2.878), 266.1 MB/s , 703.7 MB/s
   2#silesia.tar       : 211988480 ->  70162842 (3.021), 199.0 MB/s , 666.6 MB/s
   3#silesia.tar       : 211988480 ->  66997986 (3.164), 156.2 MB/s , 656.2 MB/s
   4#silesia.tar       : 211988480 ->  66002591 (3.212), 133.2 MB/s , 647.4 MB/s
   5#silesia.tar       : 211988480 ->  65008480 (3.261),  96.3 MB/s , 633.3 MB/s
This commit is contained in:
Nick Terrell
2016-10-17 15:51:15 -07:00
parent ccfcc643da
commit 4db751668f
4 changed files with 24 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/decompress/zstd_decompress.c
+6 -3
View File
@@ -1315,25 +1315,28 @@ static size_t ZSTD_loadEntropy(ZSTD_DCtx* dctx, const void* const dict, size_t c
}
{ short offcodeNCount[MaxOff+1];
U32 offcodeMaxValue=MaxOff, offcodeLog=OffFSELog;
U32 offcodeMaxValue=MaxOff, offcodeLog;
size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd-dictPtr);
if (FSE_isError(offcodeHeaderSize)) return ERROR(dictionary_corrupted);
if (offcodeLog > OffFSELog) return ERROR(dictionary_corrupted);
CHECK_E(FSE_buildDTable(dctx->OFTable, offcodeNCount, offcodeMaxValue, offcodeLog), dictionary_corrupted);
dictPtr += offcodeHeaderSize;
}
{ short matchlengthNCount[MaxML+1];
unsigned matchlengthMaxValue = MaxML, matchlengthLog = MLFSELog;
unsigned matchlengthMaxValue = MaxML, matchlengthLog;
size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd-dictPtr);
if (FSE_isError(matchlengthHeaderSize)) return ERROR(dictionary_corrupted);
if (matchlengthLog > MLFSELog) return ERROR(dictionary_corrupted);
CHECK_E(FSE_buildDTable(dctx->MLTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog), dictionary_corrupted);
dictPtr += matchlengthHeaderSize;
}
{ short litlengthNCount[MaxLL+1];
unsigned litlengthMaxValue = MaxLL, litlengthLog = LLFSELog;
unsigned litlengthMaxValue = MaxLL, litlengthLog;
size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd-dictPtr);
if (FSE_isError(litlengthHeaderSize)) return ERROR(dictionary_corrupted);
if (litlengthLog > LLFSELog) return ERROR(dictionary_corrupted);
CHECK_E(FSE_buildDTable(dctx->LLTable, litlengthNCount, litlengthMaxValue, litlengthLog), dictionary_corrupted);
dictPtr += litlengthHeaderSize;
}