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Fixed : ZSTD_compress() corrently prevents buffer overflow

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This commit is contained in:
Yann Collet
2015-07-07 01:02:04 -08:00
parent dc6c1d920a
commit 858db1291f
1 changed files with 4 additions and 3 deletions
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lib/zstd.c
+4 -3
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@@ -1089,6 +1089,7 @@ size_t ZSTD_compressContinue(ZSTD_Cctx* cctx, void* dst, size_t maxDstSize, con
const U32 updateRate = 2 * BLOCKSIZE; const U32 updateRate = 2 * BLOCKSIZE;
/* Init */ /* Init */
if (maxDstSize < ZSTD_compressBound(srcSize) - 4 /*header size*/) return (size_t)-ZSTD_ERROR_maxDstSize_tooSmall;
if (ctx->base==NULL) if (ctx->base==NULL)
ctx->base = (const BYTE*)src, ctx->current=0, ctx->nextUpdate = g_maxDistance; ctx->base = (const BYTE*)src, ctx->current=0, ctx->nextUpdate = g_maxDistance;
if (src != ctx->base + ctx->current) /* not contiguous */ if (src != ctx->base + ctx->current) /* not contiguous */
@@ -1119,7 +1120,6 @@ size_t ZSTD_compressContinue(ZSTD_Cctx* cctx, void* dst, size_t maxDstSize, con
} }
/* compress */ /* compress */
if (maxDstSize < ZSTD_blockHeaderSize) return (size_t)-ZSTD_ERROR_maxDstSize_tooSmall;
cSize = ZSTD_compressBlock(ctx, op+ZSTD_blockHeaderSize, maxDstSize-ZSTD_blockHeaderSize, ip, blockSize); cSize = ZSTD_compressBlock(ctx, op+ZSTD_blockHeaderSize, maxDstSize-ZSTD_blockHeaderSize, ip, blockSize);
if (cSize == 0) if (cSize == 0)
{ {
@@ -1165,6 +1165,7 @@ size_t ZSTD_compressEnd(ZSTD_Cctx* ctx, void* dst, size_t maxDstSize)
static size_t ZSTD_compressCCtx(ZSTD_Cctx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize) static size_t ZSTD_compressCCtx(ZSTD_Cctx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{ {
BYTE* const ostart = (BYTE* const)dst; BYTE* const ostart = (BYTE* const)dst;
BYTE* const oend = ostart + maxDstSize;
BYTE* op = ostart; BYTE* op = ostart;
/* Header */ /* Header */
@@ -1177,7 +1178,7 @@ static size_t ZSTD_compressCCtx(ZSTD_Cctx* ctx, void* dst, size_t maxDstSize, co
/* Compression */ /* Compression */
{ {
size_t cSize = ZSTD_compressContinue(ctx, op, maxDstSize, src, srcSize); size_t cSize = ZSTD_compressContinue(ctx, op, oend-op, src, srcSize);
if (ZSTD_isError(cSize)) return cSize; if (ZSTD_isError(cSize)) return cSize;
op += cSize; op += cSize;
maxDstSize -= cSize; maxDstSize -= cSize;
@@ -1185,7 +1186,7 @@ static size_t ZSTD_compressCCtx(ZSTD_Cctx* ctx, void* dst, size_t maxDstSize, co
/* Close frame */ /* Close frame */
{ {
size_t endSize = ZSTD_compressEnd(ctx, op, maxDstSize); size_t endSize = ZSTD_compressEnd(ctx, op, oend-op);
if(ZSTD_isError(endSize)) return endSize; if(ZSTD_isError(endSize)) return endSize;
op += endSize; op += endSize;
} }