diff options
| author | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-05-12 19:58:33 +0800 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-05-17 23:38:14 +0800 |
| commit | dcbe6803fffd387f72b48c2373b5f5ed12a5804b (patch) | |
| tree | 483d86612b11d67fa6c27199477822761cc8333e /fs/erofs/decompressor.c | |
| parent | 2833f4bb46f418678297ec7c535a164aa631d4c4 (diff) | |
erofs: fix buffer copy overflow of ztailpacking feature
I got some KASAN report as below:
[ 46.959738] ==================================================================
[ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
...
[ 46.960430] Call Trace:
[ 46.960430] <TASK>
[ 46.960430] dump_stack_lvl+0x41/0x5e
[ 46.960430] print_report.cold+0xb2/0x6b7
[ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] kasan_report+0x8a/0x140
[ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] kasan_check_range+0x14d/0x1d0
[ 46.960430] memcpy+0x20/0x60
[ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
The root cause is that the tail pcluster won't be a complete filesystem
block anymore. So if ztailpacking is used, the second part of an
uncompressed tail pcluster may not be ``rq->pageofs_out``.
Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
Fixes: cecf864d3d76 ("erofs: support inline data decompression")
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20220512115833.24175-1-hsiangkao@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/decompressor.c')
| -rw-r--r-- | fs/erofs/decompressor.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index 0f445f7e1df8..6dca1900c733 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq, PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; const unsigned int righthalf = min_t(unsigned int, rq->outputsize, PAGE_SIZE - rq->pageofs_out); + const unsigned int lefthalf = rq->outputsize - righthalf; unsigned char *src, *dst; if (nrpages_out > 2) { @@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq, if (nrpages_out == 2) { DBG_BUGON(!rq->out[1]); if (rq->out[1] == *rq->in) { - memmove(src, src + righthalf, rq->pageofs_out); + memmove(src, src + righthalf, lefthalf); } else { dst = kmap_atomic(rq->out[1]); - memcpy(dst, src + righthalf, rq->pageofs_out); + memcpy(dst, src + righthalf, lefthalf); kunmap_atomic(dst); } } |