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fix: adjust LDM params in estimate functions to prevent SIGFPE (issue #4590)

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Cody
2026-02-27 16:14:28 -05:00
committed by Nick Terrell
parent 117b0edfae
commit 81cf153bce
2 changed files with 29 additions and 2 deletions
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lib/compress/zstd_compress.c
+10 -2
View File
@@ -1771,15 +1771,19 @@ size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params)
{
ZSTD_compressionParameters const cParams =
ZSTD_getCParamsFromCCtxParams(params, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict);
ldmParams_t ldmParams = params->ldmParams;
ZSTD_ParamSwitch_e const useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(params->useRowMatchFinder,
&cParams);
RETURN_ERROR_IF(params->nbWorkers > 0, GENERIC, "Estimate CCtx size is supported for single-threaded compression only.");
if (ldmParams.enableLdm == ZSTD_ps_enable) {
ZSTD_ldm_adjustParameters(&ldmParams, &cParams);
}
/* estimateCCtxSize is for one-shot compression. So no buffers should
* be needed. However, we still allocate two 0-sized buffers, which can
* take space under ASAN. */
return ZSTD_estimateCCtxSize_usingCCtxParams_internal(
&cParams, &params->ldmParams, 1, useRowMatchFinder, 0, 0, ZSTD_CONTENTSIZE_UNKNOWN, ZSTD_hasExtSeqProd(params), params->maxBlockSize);
&cParams, &ldmParams, 1, useRowMatchFinder, 0, 0, ZSTD_CONTENTSIZE_UNKNOWN, ZSTD_hasExtSeqProd(params), params->maxBlockSize);
}
size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams)
@@ -1829,6 +1833,7 @@ size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
RETURN_ERROR_IF(params->nbWorkers > 0, GENERIC, "Estimate CCtx size is supported for single-threaded compression only.");
{ ZSTD_compressionParameters const cParams =
ZSTD_getCParamsFromCCtxParams(params, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict);
ldmParams_t ldmParams = params->ldmParams;
size_t const blockSize = MIN(ZSTD_resolveMaxBlockSize(params->maxBlockSize), (size_t)1 << cParams.windowLog);
size_t const inBuffSize = (params->inBufferMode == ZSTD_bm_buffered)
? ((size_t)1 << cParams.windowLog) + blockSize
@@ -1838,8 +1843,11 @@ size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
: 0;
ZSTD_ParamSwitch_e const useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(params->useRowMatchFinder, &params->cParams);
if (ldmParams.enableLdm == ZSTD_ps_enable) {
ZSTD_ldm_adjustParameters(&ldmParams, &cParams);
}
return ZSTD_estimateCCtxSize_usingCCtxParams_internal(
&cParams, &params->ldmParams, 1, useRowMatchFinder, inBuffSize, outBuffSize,
&cParams, &ldmParams, 1, useRowMatchFinder, inBuffSize, outBuffSize,
ZSTD_CONTENTSIZE_UNKNOWN, ZSTD_hasExtSeqProd(params), params->maxBlockSize);
}
}
tests/fuzzer.c
+19
View File
@@ -2515,6 +2515,25 @@ static int basicUnitTests(U32 const seed, double compressibility)
}
}
DISPLAYLEVEL(3, "OK \n");
DISPLAYLEVEL(3, "test%3i : estimation functions with LDM enabled (issue #4590) : ", testNb++);
{
/* ZSTD_estimateCCtxSize_usingCCtxParams must adjust zeroed-out
* LDM parameters when LDM is enabled, to avoid division by zero
* in ZSTD_ldm_getMaxNbSeq. */
ZSTD_CCtx_params* params = ZSTD_createCCtxParams();
size_t cctxSize;
CHECK_Z(ZSTD_CCtxParams_setParameter(params, ZSTD_c_compressionLevel, 22));
CHECK_Z(ZSTD_CCtxParams_setParameter(params, ZSTD_c_enableLongDistanceMatching, ZSTD_ps_enable));
cctxSize = ZSTD_estimateCCtxSize_usingCCtxParams(params);
if (ZSTD_isError(cctxSize)) goto _output_error;
if (cctxSize == 0) goto _output_error;
cctxSize = ZSTD_estimateCStreamSize_usingCCtxParams(params);
if (ZSTD_isError(cctxSize)) goto _output_error;
if (cctxSize == 0) goto _output_error;
ZSTD_freeCCtxParams(params);
}
DISPLAYLEVEL(3, "OK \n");
}
free(staticCCtxBuffer);
free(staticDCtxBuffer);