#syz test git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git dev-test
On 2024/3/4 11:53, Gao Xiang wrote:
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/[email protected]
Reported-by: [email protected]
Fixes: 1ca01520148a ("erofs: refine z_erofs_transform_plain() for sub-page block
support")
Signed-off-by: Gao Xiang <[email protected]>
---
fs/erofs/decompressor.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
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;
