fixed bug #73 notified by @nemequ

diff --git a/lib/zstd_compress.c b/lib/zstd_compress.c
index 53dfc742ff71906a46e315f08a32a699b8ab583e..ccfabf896a3928ba30a74cf3779b850fccc86fae 100644 (file)
--- a/lib/zstd_compress.c
+++ b/lib/zstd_compress.c
@@ -1218,8 +1218,8 @@ FORCE_INLINE size_t ZSTD_HcFindBestMatch_selectMLS (
 /* common lazy function, to be inlined */
 FORCE_INLINE
 size_t ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
-                                     void* dst, size_t maxDstSize, const void* src, size_t srcSize,
-                                     const U32 searchMethod, const U32 deep)   /* 0 : hc; 1 : bt */
+                                       void* dst, size_t maxDstSize, const void* src, size_t srcSize,
+                                 const U32 searchMethod, const U32 deep)   /* searchMethod : 0 = hc; 1 = bt */
 {
     seqStore_t* seqStorePtr = &(ctx->seqStore);
     const BYTE* const istart = (const BYTE*)src;
@@ -1496,6 +1496,7 @@ static ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int
 size_t ZSTD_compressBlock(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
 {
     ZSTD_blockCompressor blockCompressor = ZSTD_selectBlockCompressor(ctx->params.strategy, ctx->lowLimit < ctx->dictLimit);
+    if (srcSize < MIN_CBLOCK_SIZE+3) return 0;   /* don't even attempt compression below a certain srcSize */
     return blockCompressor(ctx, dst, maxDstSize, src, srcSize);
 }
 
@@ -1536,7 +1537,7 @@ static size_t ZSTD_compress_generic (ZSTD_CCtx* ctxPtr,
             op[0] = (BYTE)(cSize>>16);
             op[1] = (BYTE)(cSize>>8);
             op[2] = (BYTE)cSize;
-            op[0] += (BYTE)(bt_compressed << 6); /* is a compressed block */
+            op[0] += (BYTE)(bt_compressed << 6);   /* is a compressed block */
             cSize += 3;
         }
 

diff --git a/programs/fuzzer.c b/programs/fuzzer.c
index ec1ccbd548b648cbb626f252c65d9158884635e7..d3af3ff89b0e1abc8d0fd55e8c691aecb1bf0e9c 100644 (file)
--- a/programs/fuzzer.c
+++ b/programs/fuzzer.c
@@ -63,7 +63,7 @@
 #define MB *(1U<<20)
 #define GB *(1U<<30)
 
-static const U32 nbTestsDefault = 32 KB;
+static const U32 nbTestsDefault = 30000;
 #define COMPRESSIBLE_NOISE_LENGTH (10 MB)
 #define FUZ_COMPRESSIBILITY_DEFAULT 50
 static const U32 prime1 = 2654435761U;
@@ -89,6 +89,8 @@ static U32 g_time = 0;
 /*********************************************************
 *  Fuzzer functions
 *********************************************************/
+#define MAX(a,b) ((a)>(b)?(a):(b))
+
 static U32 FUZ_GetMilliStart(void)
 {
     struct timeb tb;
@@ -299,6 +301,7 @@ int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, double compressibilit
         U32 sampleSizeLog, buffNb, cLevelMod;
         U64 crcOrig, crcDest;
         int cLevel;
+        BYTE* sampleBuffer;
 
         /* init */
         DISPLAYUPDATE(2, "\r%6u/%6u   ", testNb, nbTests);
@@ -325,13 +328,17 @@ int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, double compressibilit
         sampleSize = (size_t)1 << sampleSizeLog;
         sampleSize += FUZ_rand(&lseed) & (sampleSize-1);
         sampleStart = FUZ_rand(&lseed) % (srcBufferSize - sampleSize);
-        crcOrig = XXH64(srcBuffer + sampleStart, sampleSize, 0);
 
-        /* HC compression test */
-#define MAX(a,b) ((a)>(b)?(a):(b))
+        /* create sample buffer (to catch read error with valgrind & sanitizers)  */
+        sampleBuffer = (BYTE*)malloc(sampleSize);
+        CHECK (sampleBuffer==NULL, "not enough memory for sample buffer");
+        memcpy(sampleBuffer, srcBuffer + sampleStart, sampleSize);
+        crcOrig = XXH64(sampleBuffer, sampleSize, 0);
+
+        /* compression test */
         cLevelMod = MAX(1, 38 - (int)(MAX(9, sampleSizeLog) * 2));   /* use high compression levels with small samples, for speed */
         cLevel = (FUZ_rand(&lseed) % cLevelMod) +1;
-        cSize = ZSTD_compressCCtx(hcctx, cBuffer, cBufferSize, srcBuffer + sampleStart, sampleSize, cLevel);
+        cSize = ZSTD_compressCCtx(hcctx, cBuffer, cBufferSize, sampleBuffer, sampleSize, cLevel);
         CHECK(ZSTD_isError(cSize), "ZSTD_compressCCtx failed");
 
         /* compression failure test : too small dest buffer */
@@ -343,7 +350,7 @@ int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, double compressibilit
             static const U32 endMark = 0x4DC2B1A9;
             U32 endCheck;
             memcpy(dstBuffer+tooSmallSize, &endMark, 4);
-            errorCode = ZSTD_compressCCtx(hcctx, dstBuffer, tooSmallSize, srcBuffer + sampleStart, sampleSize, cLevel);
+            errorCode = ZSTD_compressCCtx(hcctx, dstBuffer, tooSmallSize, sampleBuffer, sampleSize, cLevel);
             CHECK(!ZSTD_isError(errorCode), "ZSTD_compressCCtx should have failed ! (buffer too small : %u < %u)", (U32)tooSmallSize, (U32)cSize);
             memcpy(&endCheck, dstBuffer+tooSmallSize, 4);
             CHECK(endCheck != endMark, "ZSTD_compressCCtx : dst buffer overflow");
@@ -354,7 +361,9 @@ int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, double compressibilit
         dSize = ZSTD_decompress(dstBuffer, sampleSize + dSupSize, cBuffer, cSize);
         CHECK(dSize != sampleSize, "ZSTD_decompress failed (%s) (srcSize : %u ; cSize : %u)", ZSTD_getErrorName(dSize), (U32)sampleSize, (U32)cSize);
         crcDest = XXH64(dstBuffer, sampleSize, 0);
-        CHECK(crcOrig != crcDest, "decompression result corrupted (pos %u / %u)", (U32)findDiff(srcBuffer+sampleStart, dstBuffer, sampleSize), (U32)sampleSize);
+        CHECK(crcOrig != crcDest, "decompression result corrupted (pos %u / %u)", (U32)findDiff(sampleBuffer, dstBuffer, sampleSize), (U32)sampleSize);
+
+        free(sampleBuffer);   /* no longer useful after this point */
 
         /* truncated src decompression test */
         {