diff options
| -rw-r--r-- | src/liblzma/api/lzma/container.h | 24 | ||||
| -rw-r--r-- | src/liblzma/common/common.h | 1 | ||||
| -rw-r--r-- | src/liblzma/common/stream_decoder.c | 14 |
3 files changed, 37 insertions, 2 deletions
diff --git a/src/liblzma/api/lzma/container.h b/src/liblzma/api/lzma/container.h index 891c6b7a..b9c5e719 100644 --- a/src/liblzma/api/lzma/container.h +++ b/src/liblzma/api/lzma/container.h @@ -474,6 +474,30 @@ extern LZMA_API(lzma_ret) lzma_stream_buffer_encode( /** + * This flag makes lzma_code() not calculate and verify the integrity check + * of the compressed data in .xz files. This means that invalid integrity + * check values won't be detected and LZMA_DATA_ERROR won't be returned in + * such cases. + * + * This flag only affects the checks of the compressed data itself; the CRC32 + * values in the .xz headers will still be verified normally. + * + * Don't use this flag unless you know what you are doing. Possible reasons + * to use this flag: + * + * - Trying to recover data from a corrupt .xz file. + * + * - Speeding up decompression, which matters mostly with SHA-256 + * or with files that have compressed extremely well. It's recommended + * to not use this flag for this purpose unless the file integrity is + * verified externally in some other way. + * + * Support for this flag was added in liblzma 5.1.4beta. + */ +#define LZMA_IGNORE_CHECK UINT32_C(0x10) + + +/** * This flag enables decoding of concatenated files with file formats that * allow concatenating compressed files as is. From the formats currently * supported by liblzma, only the .xz format allows concatenated files. diff --git a/src/liblzma/common/common.h b/src/liblzma/common/common.h index b10a72e2..af14e479 100644 --- a/src/liblzma/common/common.h +++ b/src/liblzma/common/common.h @@ -75,6 +75,7 @@ ( LZMA_TELL_NO_CHECK \ | LZMA_TELL_UNSUPPORTED_CHECK \ | LZMA_TELL_ANY_CHECK \ + | LZMA_IGNORE_CHECK \ | LZMA_CONCATENATED ) diff --git a/src/liblzma/common/stream_decoder.c b/src/liblzma/common/stream_decoder.c index 5243e4c6..3ab938c9 100644 --- a/src/liblzma/common/stream_decoder.c +++ b/src/liblzma/common/stream_decoder.c @@ -57,6 +57,10 @@ struct lzma_coder_s { /// If true, LZMA_GET_CHECK is returned after decoding Stream Header. bool tell_any_check; + /// If true, we will tell the Block decoder to skip calculating + /// and verifying the integrity check. + bool ignore_check; + /// If true, we will decode concatenated Streams that possibly have /// Stream Padding between or after them. LZMA_STREAM_END is returned /// once the application isn't giving us any new input, and we aren't @@ -182,8 +186,8 @@ stream_decode(lzma_coder *coder, const lzma_allocator *allocator, coder->pos = 0; - // Version 0 is currently the only possible version. - coder->block_options.version = 0; + // Version 1 is needed to support the .ignore_check option. + coder->block_options.version = 1; // Set up a buffer to hold the filter chain. Block Header // decoder will initialize all members of this array so @@ -195,6 +199,11 @@ stream_decode(lzma_coder *coder, const lzma_allocator *allocator, return_if_error(lzma_block_header_decode(&coder->block_options, allocator, coder->buffer)); + // If LZMA_IGNORE_CHECK was used, this flag needs to be set. + // It has to be set after lzma_block_header_decode() because + // it always resets this to false. + coder->block_options.ignore_check = coder->ignore_check; + // Check the memory usage limit. const uint64_t memusage = lzma_raw_decoder_memusage(filters); lzma_ret ret; @@ -433,6 +442,7 @@ lzma_stream_decoder_init( next->coder->tell_unsupported_check = (flags & LZMA_TELL_UNSUPPORTED_CHECK) != 0; next->coder->tell_any_check = (flags & LZMA_TELL_ANY_CHECK) != 0; + next->coder->ignore_check = (flags & LZMA_IGNORE_CHECK) != 0; next->coder->concatenated = (flags & LZMA_CONCATENATED) != 0; next->coder->first_stream = true; |