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fix sequence validation and bounds check in ZSTD_copySequencesToSeqStore()

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This commit is contained in:
Danielle Rozenblit 2023-01-20 10:32:35 -08:00
parent bce0382c82
commit aa385ece13
2 changed files with 94 additions and 8 deletions
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18
lib/compress/zstd_compress.c
View File

@ -6156,8 +6156,8 @@ size_t ZSTD_compress2(ZSTD_CCtx* cctx,
* @returns a ZSTD error code if sequence is not valid
*/
static size_t
ZSTD_validateSequence(U32 offCode, U32 matchLength,
size_t posInSrc, U32 windowLog, size_t dictSize)
ZSTD_validateSequence(U32 offCode, U32 matchLength, U32 minMatch,
size_t posInSrc, U32 windowLog, size_t dictSize, int useExternalMatchFinder)
{
U32 const windowSize = 1u << windowLog;
/* posInSrc represents the amount of data the decoder would decode up to this point.
@ -6168,6 +6168,8 @@ ZSTD_validateSequence(U32 offCode, U32 matchLength,
size_t const offsetBound = posInSrc > windowSize ? (size_t)windowSize : posInSrc + (size_t)dictSize;
RETURN_ERROR_IF(offCode > OFFSET_TO_OFFBASE(offsetBound), corruption_detected, "Offset too large!");
RETURN_ERROR_IF(matchLength < MINMATCH, corruption_detected, "Matchlength too small");
/* Validate maxNbSeq is large enough for the given matchLength and minMatch */
RETURN_ERROR_IF(!useExternalMatchFinder && minMatch >= 4 && matchLength < 4, corruption_detected, "Matchlength too small for the minMatch");
return 0;
}
@ -6220,11 +6222,11 @@ ZSTD_copySequencesToSeqStoreExplicitBlockDelim(ZSTD_CCtx* cctx,
DEBUGLOG(6, "Storing sequence: (of: %u, ml: %u, ll: %u)", offBase, matchLength, litLength);
if (cctx->appliedParams.validateSequences) {
seqPos->posInSrc += litLength + matchLength;
FORWARD_IF_ERROR(ZSTD_validateSequence(offBase, matchLength, seqPos->posInSrc,
cctx->appliedParams.cParams.windowLog, dictSize),
FORWARD_IF_ERROR(ZSTD_validateSequence(offBase, matchLength, cctx->appliedParams.cParams.minMatch, seqPos->posInSrc,
cctx->appliedParams.cParams.windowLog, dictSize, cctx->appliedParams.useExternalMatchFinder),
"Sequence validation failed");
}
RETURN_ERROR_IF(idx - seqPos->idx > cctx->seqStore.maxNbSeq, memory_allocation,
RETURN_ERROR_IF(idx - seqPos->idx >= cctx->seqStore.maxNbSeq, memory_allocation,
"Not enough memory allocated. Try adjusting ZSTD_c_minMatch.");
ZSTD_storeSeq(&cctx->seqStore, litLength, ip, iend, offBase, matchLength);
ip += matchLength + litLength;
@ -6332,12 +6334,12 @@ ZSTD_copySequencesToSeqStoreNoBlockDelim(ZSTD_CCtx* cctx, ZSTD_sequencePosition*
if (cctx->appliedParams.validateSequences) {
seqPos->posInSrc += litLength + matchLength;
FORWARD_IF_ERROR(ZSTD_validateSequence(offBase, matchLength, seqPos->posInSrc,
cctx->appliedParams.cParams.windowLog, dictSize),
FORWARD_IF_ERROR(ZSTD_validateSequence(offBase, matchLength, cctx->appliedParams.cParams.minMatch, seqPos->posInSrc,
cctx->appliedParams.cParams.windowLog, dictSize, cctx->appliedParams.useExternalMatchFinder),
"Sequence validation failed");
}
DEBUGLOG(6, "Storing sequence: (of: %u, ml: %u, ll: %u)", offBase, matchLength, litLength);
RETURN_ERROR_IF(idx - seqPos->idx > cctx->seqStore.maxNbSeq, memory_allocation,
RETURN_ERROR_IF(idx - seqPos->idx >= cctx->seqStore.maxNbSeq, memory_allocation,
"Not enough memory allocated. Try adjusting ZSTD_c_minMatch.");
ZSTD_storeSeq(&cctx->seqStore, litLength, ip, iend, offBase, matchLength);
ip += matchLength + litLength;

84
tests/zstreamtest.c
View File

@ -2066,6 +2066,90 @@ static int basicUnitTests(U32 seed, double compressibility, int bigTests)
}
DISPLAYLEVEL(3, "OK \n");
/* Test Sequence Validation */
DISPLAYLEVEL(3, "test%3i : Testing sequence validation: ", testNb++);
{
ZSTD_CCtx* cctx = ZSTD_createCCtx();
/* Test minMatch >= 4, matchLength < 4 */
{
size_t srcSize = 11;
void* const src = CNBuffer;
size_t dstSize = ZSTD_compressBound(srcSize);
void* const dst = compressedBuffer;
size_t const kNbSequences = 4;
ZSTD_Sequence* sequences = malloc(sizeof(ZSTD_Sequence) * kNbSequences);
memset(src, 'x', srcSize);
sequences[0] = (ZSTD_Sequence) {1, 1, 3, 0};
sequences[1] = (ZSTD_Sequence) {1, 0, 3, 0};
sequences[2] = (ZSTD_Sequence) {1, 0, 3, 0};
sequences[3] = (ZSTD_Sequence) {0, 1, 0, 0};
/* Test with sequence validation */
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_minMatch, 5));
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_blockDelimiters, ZSTD_sf_explicitBlockDelimiters));
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_validateSequences, 1));
cSize = ZSTD_compressSequences(cctx, dst, dstSize,
sequences, kNbSequences,
src, srcSize);
CHECK(!ZSTD_isError(cSize), "Should throw an error"); /* maxNbSeq is too small and an assert will fail */
ZSTD_CCtx_reset(cctx, ZSTD_reset_session_and_parameters);
/* Test without sequence validation */
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_minMatch, 5));
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_blockDelimiters, ZSTD_sf_explicitBlockDelimiters));
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_validateSequences, 0));
cSize = ZSTD_compressSequences(cctx, dst, dstSize,
sequences, kNbSequences,
src, srcSize);
CHECK(!ZSTD_isError(cSize), "Should throw an error"); /* maxNbSeq is too small and an assert will fail */
free(sequences);
}
ZSTD_CCtx_reset(cctx, ZSTD_reset_session_and_parameters);
{ /* Test case with two additional sequences */
size_t srcSize = 19;
void* const src = CNBuffer;
size_t dstSize = ZSTD_compressBound(srcSize);
void* const dst = compressedBuffer;
size_t const kNbSequences = 7;
ZSTD_Sequence* sequences = malloc(sizeof(ZSTD_Sequence) * kNbSequences);
memset(src, 'x', srcSize);
sequences[0] = (ZSTD_Sequence) {1, 1, 3, 0};
sequences[1] = (ZSTD_Sequence) {1, 0, 3, 0};
sequences[2] = (ZSTD_Sequence) {1, 0, 3, 0};
sequences[3] = (ZSTD_Sequence) {1, 0, 3, 0};
sequences[4] = (ZSTD_Sequence) {1, 0, 3, 0};
sequences[5] = (ZSTD_Sequence) {1, 0, 3, 0};
sequences[6] = (ZSTD_Sequence) {0, 0, 0, 0};
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_minMatch, 5));
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_blockDelimiters, ZSTD_sf_explicitBlockDelimiters));
CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_validateSequences, 1));
cSize = ZSTD_compressSequences(cctx, dst, dstSize,
sequences, kNbSequences,
src, srcSize);
CHECK(!ZSTD_isError(cSize), "Should throw an error"); /* maxNbSeq is too small and an assert will fail */
free(sequences);
}
ZSTD_freeCCtx(cctx);
}
DISPLAYLEVEL(3, "OK \n");
_end:
FUZ_freeDictionary(dictionary);
ZSTD_freeCStream(zc);