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authorGao Xiang <hsiangkao@linux.alibaba.com>2024-03-04 11:53:39 +0800
committerGao Xiang <hsiangkao@linux.alibaba.com>2024-03-07 10:21:00 +0800
commit893e5e9b7369a02e7ceaa6d98db6739162005b03 (patch)
treeba940e04acedfc268fbf41548dc388965faa22a1 /fs
parent90d35da658da8cff0d4ecbb5113f5fac9d00eb72 (diff)
erofs: fix uninitialized page cache reported by KMSAN
syzbot reports a KMSAN reproducer [1] which generates a crafted filesystem image and causes IMA to read uninitialized page cache. Later, (rq->outputsize > rq->inputsize) will be formally supported after either large uncompressed pclusters (> block size) or big lclusters are landed. However, currently there is no way to generate such filesystems by using mkfs.erofs. Thus, let's mark this condition as unsupported for now. [1] https://lore.kernel.org/r/0000000000002be12a0611ca7ff8@google.com Reported-and-tested-by: syzbot+7bc44a489f0ef0670bd5@syzkaller.appspotmail.com Fixes: 1ca01520148a ("erofs: refine z_erofs_transform_plain() for sub-page block support") Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Yue Hu <huyue2@coolpad.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240304035339.425857-1-hsiangkao@linux.alibaba.com
Diffstat (limited to 'fs')
-rw-r--r--fs/erofs/decompressor.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index d4cee95af14c..2ec9b2bb628d 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -323,7 +323,8 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
unsigned int cur = 0, ni = 0, no, pi, po, insz, cnt;
u8 *kin;
- DBG_BUGON(rq->outputsize > rq->inputsize);
+ if (rq->outputsize > rq->inputsize)
+ return -EOPNOTSUPP;
if (rq->alg == Z_EROFS_COMPRESSION_INTERLACED) {
cur = bs - (rq->pageofs_out & (bs - 1));
pi = (rq->pageofs_in + rq->inputsize - cur) & ~PAGE_MASK;