tree 148fa15f84c3fcea07fa515dcc305494417a46b0
parent 386292919c255da42ff6d6d3c51594f796ac146a
author Lasse Collin <lasse.collin@tukaani.org> 1633901499 +0800
committer Gao Xiang <hsiangkao@linux.alibaba.com> 1634658270 +0800

lib/xz: Avoid overlapping memcpy() with invalid input with in-place decompression

With valid files, the safety margin described in lib/decompress_unxz.c
ensures that these buffers cannot overlap. But if the uncompressed size
of the input is larger than the caller thought, which is possible when
the input file is invalid/corrupt, the buffers can overlap. Obviously
the result will then be garbage (and usually the decoder will return
an error too) but no other harm will happen when such an over-run occurs.

This change only affects uncompressed LZMA2 chunks and so this
should have no effect on performance.

Link: https://lore.kernel.org/r/20211010213145.17462-2-xiang@kernel.org
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>