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Merge pull request #2362 from senhuang42/fix_ldm_fuzz_issue 

Fix long distance matcher OSS-fuzz issue
dev
Nick Terrell 2020-10-27 11:13:03 -07:00 committed by GitHub
parent 284d84ecf7 4d01979b62
commit 0953645837
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 13 additions and 5 deletions
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7
lib/compress/zstd_compress.c
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@ -2374,7 +2374,11 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
/* Assert that we have correctly flushed the ctx params into the ms's copy */
ZSTD_assertEqualCParams(zc->appliedParams.cParams, ms->cParams);
if (srcSize < MIN_CBLOCK_SIZE+ZSTD_blockHeaderSize+1) {
ZSTD_ldm_skipSequences(&zc->externSeqStore, srcSize, zc->appliedParams.cParams.minMatch);
if (zc->appliedParams.cParams.strategy >= ZSTD_btopt) {
ZSTD_ldm_skipRawSeqStoreBytes(&zc->externSeqStore, srcSize);
} else {
ZSTD_ldm_skipSequences(&zc->externSeqStore, srcSize, zc->appliedParams.cParams.minMatch);
}
return ZSTDbss_noCompress; /* don't even attempt compression below a certain srcSize */
}
ZSTD_resetSeqStore(&(zc->seqStore));
@ -2853,6 +2857,7 @@ size_t ZSTD_referenceExternalSequences(ZSTD_CCtx* cctx, rawSeq* seq, size_t nbSe
cctx->externSeqStore.size = nbSeq;
cctx->externSeqStore.capacity = nbSeq;
cctx->externSeqStore.pos = 0;
cctx->externSeqStore.posInSequence = 0;
return 0;
}

5
lib/compress/zstd_ldm.c
View File

@ -577,10 +577,7 @@ static rawSeq maybeSplitSequence(rawSeqStore_t* rawSeqStore,
return sequence;
}
/* ZSTD_ldm_skipRawSeqStoreBytes():
* Moves forward in rawSeqStore by nbBytes, updating fields 'pos' and 'posInSequence'.
*/
static void ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes) {
void ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes) {
U32 currPos = (U32)(rawSeqStore->posInSequence + nbBytes);
while (currPos && rawSeqStore->pos < rawSeqStore->size) {
rawSeq currSeq = rawSeqStore->seq[rawSeqStore->pos];

6
lib/compress/zstd_ldm.h
View File

@ -78,6 +78,12 @@ size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore,
void ZSTD_ldm_skipSequences(rawSeqStore_t* rawSeqStore, size_t srcSize,
U32 const minMatch);
/* ZSTD_ldm_skipRawSeqStoreBytes():
* Moves forward in rawSeqStore by nbBytes, updating fields 'pos' and 'posInSequence'.
* Not to be used in conjunction with ZSTD_ldm_skipSequences().
* Must be called for data with is not passed to ZSTD_ldm_blockCompress().
*/
void ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes);
/** ZSTD_ldm_getTableSize() :
* Estimate the space needed for long distance matching tables or 0 if LDM is