diff options
Diffstat (limited to '')
| -rw-r--r-- | src/liblzma/common/alone_decoder.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/src/liblzma/common/alone_decoder.c b/src/liblzma/common/alone_decoder.c index d35aff67..c1360ca1 100644 --- a/src/liblzma/common/alone_decoder.c +++ b/src/liblzma/common/alone_decoder.c @@ -26,6 +26,11 @@ struct lzma_coder_s { SEQ_CODE, } sequence; + /// If true, reject files that are unlikely to be .lzma files. + /// If false, more non-.lzma files get accepted and will give + /// LZMA_DATA_ERROR either immediately or after a few output bytes. + bool picky; + /// Position in the header fields size_t pos; @@ -68,13 +73,13 @@ alone_decode(lzma_coder *coder, |= (size_t)(in[*in_pos]) << (coder->pos * 8); if (++coder->pos == 4) { - if (coder->options.dict_size != UINT32_MAX) { + if (coder->picky && coder->options.dict_size + != UINT32_MAX) { // A hack to ditch tons of false positives: // We allow only dictionary sizes that are // 2^n or 2^n + 2^(n-1). LZMA_Alone created // only files with 2^n, but accepts any - // dictionary size. If someone complains, this - // will be reconsidered. + // dictionary size. uint32_t d = coder->options.dict_size - 1; d |= d >> 2; d |= d >> 3; @@ -103,9 +108,9 @@ alone_decode(lzma_coder *coder, // Another hack to ditch false positives: Assume that // if the uncompressed size is known, it must be less - // than 256 GiB. Again, if someone complains, this - // will be reconsidered. - if (coder->uncompressed_size != LZMA_VLI_UNKNOWN + // than 256 GiB. + if (coder->picky + && coder->uncompressed_size != LZMA_VLI_UNKNOWN && coder->uncompressed_size >= (LZMA_VLI_C(1) << 38)) return LZMA_FORMAT_ERROR; @@ -189,7 +194,7 @@ alone_decoder_memconfig(lzma_coder *coder, uint64_t *memusage, extern lzma_ret lzma_alone_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator, - uint64_t memlimit) + uint64_t memlimit, bool picky) { lzma_next_coder_init(&lzma_alone_decoder_init, next, allocator); @@ -208,6 +213,7 @@ lzma_alone_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator, } next->coder->sequence = SEQ_PROPERTIES; + next->coder->picky = picky; next->coder->pos = 0; next->coder->options.dict_size = 0; next->coder->options.preset_dict = NULL; @@ -223,7 +229,7 @@ lzma_alone_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator, extern LZMA_API(lzma_ret) lzma_alone_decoder(lzma_stream *strm, uint64_t memlimit) { - lzma_next_strm_init(lzma_alone_decoder_init, strm, memlimit); + lzma_next_strm_init(lzma_alone_decoder_init, strm, memlimit, false); strm->internal->supported_actions[LZMA_RUN] = true; strm->internal->supported_actions[LZMA_FINISH] = true; |