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Added : fuzzer tests : decompressing noisy src

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This commit is contained in:
Yann Collet
2015-08-21 02:44:20 +01:00
parent 7d20acd340
commit 997f9ee2ef
3 changed files with 109 additions and 204 deletions
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48
programs/fuzzer.c
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@ -177,8 +177,7 @@ static void FUZ_generateSynthetic(void* buffer, size_t bufferSize, double proba,
}
/*
static unsigned FUZ_highbit(U32 v32)
static unsigned FUZ_highbit32(U32 v32)
{
unsigned nbBits = 0;
if (v32==0) return 0;
@ -189,7 +188,6 @@ static unsigned FUZ_highbit(U32 v32)
}
return nbBits;
}
*/
static int basicUnitTests(U32 seed, double compressibility)
@ -405,6 +403,50 @@ int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, double compressibilit
CHECK(!ZSTD_isError(errorCode), "ZSTD_decompress should have failed : %u > %u (dst buffer too small)", (U32)errorCode, (U32)tooSmallSize);
CHECK(dstBuffer[tooSmallSize] != token, "ZSTD_decompress : dst buffer overflow");
}
/* noisy src decompression test */
if (cSize > 6)
{
const U32 maxNbBits = FUZ_highbit32((U32)(cSize-4));
size_t pos = 4; /* preserve magic number (too easy to detect) */
U32 nbBits = FUZ_rand(&lseed) % maxNbBits;
size_t mask = (1<<nbBits) - 1;
size_t skipLength = FUZ_rand(&lseed) & mask;
pos += skipLength;
while (pos < cSize)
{
/* add noise */
size_t noiseStart, noiseLength;
nbBits = FUZ_rand(&lseed) % maxNbBits;
if (nbBits>0) nbBits--;
mask = (1<<nbBits) - 1;
noiseLength = (FUZ_rand(&lseed) & mask) + 1;
noiseStart = FUZ_rand(&lseed) % (srcBufferSize - noiseLength);
memcpy(cBuffer + pos, srcBuffer + noiseStart, noiseLength);
pos += noiseLength;
/* keep some original src */
nbBits = FUZ_rand(&lseed) % maxNbBits;
mask = (1<<nbBits) - 1;
skipLength = FUZ_rand(&lseed) & mask;
pos += skipLength;
}
/* decompress noisy source */
{
const U32 endMark = 0xA9B1C3D6;
U32 endCheck;
size_t errorCode;
memcpy(dstBuffer+sampleSize, &endMark, 4);
errorCode = ZSTD_decompress(dstBuffer, sampleSize, cBuffer, cSize);
/* result *may* be an unlikely success, but even then, it must strictly respect dest buffer boundaries */
CHECK((!ZSTD_isError(errorCode)) && (errorCode>sampleSize),
"ZSTD_decompress on noisy src : result is too large : %u > %u (dst buffer)", (U32)errorCode, (U32)sampleSize);
memcpy(&endCheck, dstBuffer+sampleSize, 4);
CHECK(endMark!=endCheck, "ZSTD_decompress on noisy src : dst buffer overflow");
}
}
}
DISPLAY("\rAll fuzzer tests completed \n");