diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/zstd/decompress/zstd_decompress.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/lib/zstd/decompress/zstd_decompress.c b/lib/zstd/decompress/zstd_decompress.c index b9b935a9f5c0..6b3177c94711 100644 --- a/lib/zstd/decompress/zstd_decompress.c +++ b/lib/zstd/decompress/zstd_decompress.c @@ -798,7 +798,7 @@ static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity, if (srcSize == 0) return 0; RETURN_ERROR(dstBuffer_null, ""); } - ZSTD_memcpy(dst, src, srcSize); + ZSTD_memmove(dst, src, srcSize); return srcSize; } @@ -858,6 +858,7 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx, /* Loop on each block */ while (1) { + BYTE* oBlockEnd = oend; size_t decodedSize; blockProperties_t blockProperties; size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSrcSize, &blockProperties); @@ -867,16 +868,34 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx, remainingSrcSize -= ZSTD_blockHeaderSize; RETURN_ERROR_IF(cBlockSize > remainingSrcSize, srcSize_wrong, ""); + if (ip >= op && ip < oBlockEnd) { + /* We are decompressing in-place. Limit the output pointer so that we + * don't overwrite the block that we are currently reading. This will + * fail decompression if the input & output pointers aren't spaced + * far enough apart. + * + * This is important to set, even when the pointers are far enough + * apart, because ZSTD_decompressBlock_internal() can decide to store + * literals in the output buffer, after the block it is decompressing. + * Since we don't want anything to overwrite our input, we have to tell + * ZSTD_decompressBlock_internal to never write past ip. + * + * See ZSTD_allocateLiteralsBuffer() for reference. + */ + oBlockEnd = op + (ip - op); + } + switch(blockProperties.blockType) { case bt_compressed: - decodedSize = ZSTD_decompressBlock_internal(dctx, op, (size_t)(oend-op), ip, cBlockSize, /* frame */ 1, not_streaming); + decodedSize = ZSTD_decompressBlock_internal(dctx, op, (size_t)(oBlockEnd-op), ip, cBlockSize, /* frame */ 1, not_streaming); break; case bt_raw : + /* Use oend instead of oBlockEnd because this function is safe to overlap. It uses memmove. */ decodedSize = ZSTD_copyRawBlock(op, (size_t)(oend-op), ip, cBlockSize); break; case bt_rle : - decodedSize = ZSTD_setRleBlock(op, (size_t)(oend-op), *ip, blockProperties.origSize); + decodedSize = ZSTD_setRleBlock(op, (size_t)(oBlockEnd-op), *ip, blockProperties.origSize); break; case bt_reserved : default: |