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authorLasse Collin <lasse.collin@tukaani.org>2022-09-09 13:51:57 +0300
committerLasse Collin <lasse.collin@tukaani.org>2022-09-09 13:51:57 +0300
commitf8ee61e74eb40600445fdb601c374d582e1e9c8a (patch)
tree7f2d7b0545b4824a91b3947b220b77987c791ba3 /src/liblzma/api/lzma
parentliblzma: lzma_index_append: Add missing integer overflow check. (diff)
downloadxz-f8ee61e74eb40600445fdb601c374d582e1e9c8a.tar.xz
liblzma: lzma_filters_copy: Keep dest[] unmodified if an error occurs.
lzma_stream_encoder() and lzma_stream_encoder_mt() always assumed this. Before this patch, failing lzma_filters_copy() could result in free(invalid_pointer) or invalid memory reads in stream_encoder.c or stream_encoder_mt.c. To trigger this, allocating memory for a filter options structure has to fail. These are tiny allocations so in practice they very rarely fail. Certain badness in the filter chain array could also make lzma_filters_copy() fail but both stream_encoder.c and stream_encoder_mt.c validate the filter chain before trying to copy it, so the crash cannot occur this way.
Diffstat (limited to 'src/liblzma/api/lzma')
-rw-r--r--src/liblzma/api/lzma/filter.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/src/liblzma/api/lzma/filter.h b/src/liblzma/api/lzma/filter.h
index 8c859314..04825c65 100644
--- a/src/liblzma/api/lzma/filter.h
+++ b/src/liblzma/api/lzma/filter.h
@@ -108,7 +108,9 @@ extern LZMA_API(lzma_bool) lzma_filter_decoder_is_supported(lzma_vli id)
* need to be initialized by the caller in any way.
*
* If an error occurs, memory possibly already allocated by this function
- * is always freed.
+ * is always freed. liblzma versions older than 5.2.7 may modify the dest
+ * array and leave its contents in an undefined state if an error occurs.
+ * liblzma 5.2.7 and newer only modify the dest array when returning LZMA_OK.
*
* \return - LZMA_OK
* - LZMA_MEM_ERROR