diff options
| -rw-r--r-- | lib/lz4.h | 12 |
1 files changed, 7 insertions, 5 deletions
@@ -206,15 +206,17 @@ LZ4LIB_API int LZ4_compress_destSize (const char* src, char* dst, int* srcSizePt /*! LZ4_decompress_fast() : **unsafe!** This function is a bit faster than LZ4_decompress_safe(), -but doesn't provide any security guarantee. +but it may misbehave on malformed input because it doesn't perform full validation of compressed data. originalSize : is the uncompressed size to regenerate Destination buffer must be already allocated, and its size must be >= 'originalSize' bytes. return : number of bytes read from source buffer (== compressed size). If the source stream is detected malformed, the function stops decoding and return a negative result. - note : This function respects memory boundaries for *properly formed* compressed data. - However, it does not provide any protection against malicious input. - It also doesn't know 'src' size, and implies it's >= compressed size. - Use this function in trusted environment **only**. + note : This function is only usable if the originalSize of uncompressed data is known in advance. + The caller should also check that all the compressed input has been consumed properly, + i.e. that the return value matches the size of the buffer with compressed input. + The function never writes past the output buffer. However, since it doesn't know its 'src' size, + it may read past the intended input. Also, because match offsets are not validated during decoding, + reads from 'src' may underflow. Use this function in trusted environment **only**. */ LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize); |