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Merge pull request #1204 from facebook/noForwardProgress

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Error code on no forward progress
This commit is contained in:
Yann Collet 2018-06-22 20:25:29 -07:00 committed by GitHub
commit 59bb5f7d58
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3 changed files with 61 additions and 5 deletions
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28
lib/decompress/zstd_decompress.c
View File

@ -41,6 +41,17 @@
#endif
/*!
* NO_FORWARD_PROGRESS_MAX :
* maximum allowed nb of calls to ZSTD_decompressStream() and ZSTD_decompress_generic()
* without any forward progress
* (defined as: no byte read from input, and no byte flushed to output)
* before triggering an error.
*/
#ifndef ZSTD_NO_FORWARD_PROGRESS_MAX
# define ZSTD_NO_FORWARD_PROGRESS_MAX 16
#endif
/*-*******************************************************
* Dependencies
*********************************************************/
@ -153,6 +164,7 @@ struct ZSTD_DCtx_s
U32 previousLegacyVersion;
U32 legacyVersion;
U32 hostageByte;
int noForwardProgress;
/* workspace */
BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH];
@ -194,6 +206,7 @@ static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx)
dctx->streamStage = zdss_init;
dctx->legacyContext = NULL;
dctx->previousLegacyVersion = 0;
dctx->noForwardProgress = 0;
dctx->bmi2 = ZSTD_cpuid_bmi2(ZSTD_cpuid());
}
@ -2620,6 +2633,7 @@ size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t di
{
DEBUGLOG(4, "ZSTD_initDStream_usingDict");
zds->streamStage = zdss_init;
zds->noForwardProgress = 0;
CHECK_F( ZSTD_DCtx_loadDictionary(zds, dict, dictSize) );
return ZSTD_frameHeaderSize_prefix;
}
@ -2960,8 +2974,18 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
} }
/* result */
input->pos += (size_t)(ip-istart);
output->pos += (size_t)(op-ostart);
input->pos = (size_t)(ip - (const char*)(input->src));
output->pos = (size_t)(op - (char*)(output->dst));
if ((ip==istart) && (op==ostart)) { /* no forward progress */
zds->noForwardProgress ++;
if (zds->noForwardProgress >= ZSTD_NO_FORWARD_PROGRESS_MAX) {
if (op==oend) return ERROR(dstSize_tooSmall);
if (ip==iend) return ERROR(srcSize_wrong);
assert(0);
}
} else {
zds->noForwardProgress = 0;
}
{ size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds);
if (!nextSrcSizeHint) { /* frame fully decoded */
if (zds->outEnd == zds->outStart) { /* output fully flushed */

4
tests/fuzzer.c
View File

@ -66,6 +66,9 @@ static UTIL_time_t g_displayClock = UTIL_TIME_INITIALIZER;
if (g_displayLevel>=4) fflush(stderr); } }
/*-*******************************************************
* Compile time test
*********************************************************/
#undef MIN
#undef MAX
void FUZ_bug976(void)
@ -74,6 +77,7 @@ void FUZ_bug976(void)
assert(ZSTD_CHAINLOG_MAX < 31);
}
/*-*******************************************************
* Internal functions
*********************************************************/

34
tests/zstreamtest.c
View File

@ -433,11 +433,12 @@ static int basicUnitTests(U32 seed, double compressibility)
inBuff.pos = 0;
outBuff.pos = 0;
while (r) { /* skippable frame */
size_t const inSize = FUZ_rand(&coreSeed) & 15;
size_t const outSize = FUZ_rand(&coreSeed) & 15;
size_t const inSize = (FUZ_rand(&coreSeed) & 15) + 1;
size_t const outSize = (FUZ_rand(&coreSeed) & 15) + 1;
inBuff.size = inBuff.pos + inSize;
outBuff.size = outBuff.pos + outSize;
r = ZSTD_decompressStream(zd, &outBuff, &inBuff);
if (ZSTD_isError(r)) DISPLAYLEVEL(4, "ZSTD_decompressStream on skippable frame error : %s \n", ZSTD_getErrorName(r));
if (ZSTD_isError(r)) goto _output_error;
}
/* normal frame */
@ -445,14 +446,17 @@ static int basicUnitTests(U32 seed, double compressibility)
r=1;
while (r) {
size_t const inSize = FUZ_rand(&coreSeed) & 15;
size_t const outSize = FUZ_rand(&coreSeed) & 15;
size_t const outSize = (FUZ_rand(&coreSeed) & 15) + (!inSize); /* avoid having both sizes at 0 => would trigger a no_forward_progress error */
inBuff.size = inBuff.pos + inSize;
outBuff.size = outBuff.pos + outSize;
r = ZSTD_decompressStream(zd, &outBuff, &inBuff);
if (ZSTD_isError(r)) DISPLAYLEVEL(4, "ZSTD_decompressStream error : %s \n", ZSTD_getErrorName(r));
if (ZSTD_isError(r)) goto _output_error;
}
}
if (outBuff.pos != CNBufferSize) DISPLAYLEVEL(4, "outBuff.pos != CNBufferSize : should have regenerated same amount ! \n");
if (outBuff.pos != CNBufferSize) goto _output_error; /* should regenerate the same amount */
if (inBuff.pos != cSize) DISPLAYLEVEL(4, "inBuff.pos != cSize : should have real all input ! \n");
if (inBuff.pos != cSize) goto _output_error; /* should have read the entire frame */
DISPLAYLEVEL(3, "OK \n");
@ -464,6 +468,30 @@ static int basicUnitTests(U32 seed, double compressibility)
} }
DISPLAYLEVEL(3, "OK \n");
/* Decompression forward progress */
DISPLAYLEVEL(3, "test%3i : generate error when ZSTD_decompressStream() doesn't progress : ", testNb++);
{ /* skippable frame */
size_t r = 0;
int decNb = 0;
int const maxDec = 100;
inBuff.src = compressedBuffer;
inBuff.size = cSize;
inBuff.pos = 0;
outBuff.dst = decodedBuffer;
outBuff.pos = 0;
outBuff.size = CNBufferSize-1; /* 1 byte missing */
for (decNb=0; decNb<maxDec; decNb++) {
if (r==0) ZSTD_initDStream_usingDict(zd, CNBuffer, dictSize);
r = ZSTD_decompressStream(zd, &outBuff, &inBuff);
if (ZSTD_isError(r)) break;
}
if (!ZSTD_isError(r)) DISPLAYLEVEL(4, "ZSTD_decompressStream should have triggered a no_forward_progress error \n");
if (!ZSTD_isError(r)) goto _output_error; /* should have triggered no_forward_progress error */
}
DISPLAYLEVEL(3, "OK \n");
/* _srcSize compression test */
DISPLAYLEVEL(3, "test%3i : compress_srcSize %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH);
ZSTD_initCStream_srcSize(zc, 1, CNBufferSize);