ddidderr/zstd-rs
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[lib] Fix NULL pointer dereference

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When the output buffer is `NULL` with size 0, but the frame content size
is non-zero, we will write to the NULL pointer because our bounds check
underflowed.

This was exposed by a recent PR that allowed an empty frame into the
single-pass shortcut in streaming mode.

* Fix the bug.
* Fix another NULL dereference in zstd-v1.
* Overflow checks in 32-bit mode.
* Add a dedicated test.
* Expose the bug in the dedicated simple_decompress fuzzer.
* Switch all mallocs in fuzzers to return NULL for size=0.
* Fix a new timeout in a fuzzer.

Neither clang nor gcc show a decompression speed regression on x86-64.
On x86-32 clang is slightly positive and gcc loses 2.5% of speed.

Credit to OSS-Fuzz.
This commit is contained in:
Nick Terrell
2020-05-06 12:09:02 -07:00
committed by Nick Terrell
parent ad8dbae1b7
commit 5717bd39ee
26 changed files with 167 additions and 80 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/legacy/zstd_v01.c
+11 -5
View File
@@ -1078,7 +1078,7 @@ static size_t HUF_decompress_usingDTable( /* -3% slower when non static */
BYTE* const ostart = (BYTE*) dst;
BYTE* op = ostart;
BYTE* const omax = op + maxDstSize;
BYTE* const olimit = omax-15;
BYTE* const olimit = maxDstSize < 15 ? op : omax-15;
const void* ptr = DTable;
const HUF_DElt* const dt = (const HUF_DElt*)(ptr)+1;
@@ -1483,7 +1483,9 @@ static size_t ZSTDv01_getcBlockSize(const void* src, size_t srcSize, blockProper
static size_t ZSTD_copyUncompressedBlock(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
if (srcSize > maxDstSize) return ERROR(dstSize_tooSmall);
memcpy(dst, src, srcSize);
if (srcSize > 0) {
memcpy(dst, src, srcSize);
}
return srcSize;
}
@@ -1541,7 +1543,9 @@ static size_t ZSTDv01_decodeLiteralsBlock(void* ctx,
size_t rleSize = litbp.origSize;
if (rleSize>maxDstSize) return ERROR(dstSize_tooSmall);
if (!srcSize) return ERROR(srcSize_wrong);
memset(oend - rleSize, *ip, rleSize);
if (rleSize > 0) {
memset(oend - rleSize, *ip, rleSize);
}
*litStart = oend - rleSize;
*litSize = rleSize;
ip++;
@@ -1901,8 +1905,10 @@ static size_t ZSTD_decompressSequences(
{
size_t lastLLSize = litEnd - litPtr;
if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
if (op != litPtr) memmove(op, litPtr, lastLLSize);
op += lastLLSize;
if (lastLLSize > 0) {
if (op != litPtr) memmove(op, litPtr, lastLLSize);
op += lastLLSize;
}
}
}
lib/legacy/zstd_v02.c
+7 -3
View File
@@ -2836,7 +2836,9 @@ static size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, blockPropertie
static size_t ZSTD_copyUncompressedBlock(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
if (srcSize > maxDstSize) return ERROR(dstSize_tooSmall);
memcpy(dst, src, srcSize);
if (srcSize > 0) {
memcpy(dst, src, srcSize);
}
return srcSize;
}
@@ -3229,8 +3231,10 @@ static size_t ZSTD_decompressSequences(
size_t lastLLSize = litEnd - litPtr;
if (litPtr > litEnd) return ERROR(corruption_detected);
if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
if (op != litPtr) memmove(op, litPtr, lastLLSize);
op += lastLLSize;
if (lastLLSize > 0) {
if (op != litPtr) memmove(op, litPtr, lastLLSize);
op += lastLLSize;
}
}
}
lib/legacy/zstd_v03.c
+7 -3
View File
@@ -2477,7 +2477,9 @@ static size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, blockPropertie
static size_t ZSTD_copyUncompressedBlock(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
if (srcSize > maxDstSize) return ERROR(dstSize_tooSmall);
memcpy(dst, src, srcSize);
if (srcSize > 0) {
memcpy(dst, src, srcSize);
}
return srcSize;
}
@@ -2870,8 +2872,10 @@ static size_t ZSTD_decompressSequences(
size_t lastLLSize = litEnd - litPtr;
if (litPtr > litEnd) return ERROR(corruption_detected);
if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
if (op != litPtr) memmove(op, litPtr, lastLLSize);
op += lastLLSize;
if (lastLLSize > 0) {
if (op != litPtr) memmove(op, litPtr, lastLLSize);
op += lastLLSize;
}
}
}
lib/legacy/zstd_v04.c
+7 -3
View File
@@ -2603,7 +2603,9 @@ static size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, blockPropertie
static size_t ZSTD_copyRawBlock(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
if (srcSize > maxDstSize) return ERROR(dstSize_tooSmall);
memcpy(dst, src, srcSize);
if (srcSize > 0) {
memcpy(dst, src, srcSize);
}
return srcSize;
}
@@ -3008,8 +3010,10 @@ static size_t ZSTD_decompressSequences(
size_t lastLLSize = litEnd - litPtr;
if (litPtr > litEnd) return ERROR(corruption_detected);
if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
if (op != litPtr) memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
if (lastLLSize > 0) {
if (op != litPtr) memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
}
}
}
lib/legacy/zstd_v05.c
+4 -2
View File
@@ -3362,8 +3362,10 @@ static size_t ZSTDv05_decompressSequences(
size_t lastLLSize = litEnd - litPtr;
if (litPtr > litEnd) return ERROR(corruption_detected); /* too many literals already used */
if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
if (lastLLSize > 0) {
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
}
}
return op-ostart;
lib/legacy/zstd_v06.c
+4 -2
View File
@@ -3501,8 +3501,10 @@ static size_t ZSTDv06_decompressSequences(
{ size_t const lastLLSize = litEnd - litPtr;
if (litPtr > litEnd) return ERROR(corruption_detected); /* too many literals already used */
if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
if (lastLLSize > 0) {
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
}
}
return op-ostart;
lib/legacy/zstd_v07.c
+10 -4
View File
@@ -3272,7 +3272,9 @@ static size_t ZSTDv07_getcBlockSize(const void* src, size_t srcSize, blockProper
static size_t ZSTDv07_copyRawBlock(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
if (srcSize > dstCapacity) return ERROR(dstSize_tooSmall);
memcpy(dst, src, srcSize);
if (srcSize > 0) {
memcpy(dst, src, srcSize);
}
return srcSize;
}
@@ -3714,8 +3716,10 @@ static size_t ZSTDv07_decompressSequences(
{ size_t const lastLLSize = litEnd - litPtr;
/* if (litPtr > litEnd) return ERROR(corruption_detected); */ /* too many literals already used */
if (lastLLSize > (size_t)(oend-op)) return ERROR(dstSize_tooSmall);
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
if (lastLLSize > 0) {
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
}
}
return op-ostart;
@@ -3776,7 +3780,9 @@ ZSTDLIBv07_API size_t ZSTDv07_insertBlock(ZSTDv07_DCtx* dctx, const void* blockS
static size_t ZSTDv07_generateNxBytes(void* dst, size_t dstCapacity, BYTE byte, size_t length)
{
if (length > dstCapacity) return ERROR(dstSize_tooSmall);
memset(dst, byte, length);
if (length > 0) {
memset(dst, byte, length);
}
return length;
}