This is a note to let you know that I've just added the patch titled
fs/jfs: Add check for negative db_l2nbperpage
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-jfs-add-check-for-negative-db_l2nbperpage.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6e51303e85c6d675e8bc83d9ae9235e6fc90b7e8
Author: Juntong Deng <juntong.deng@xxxxxxxxxxx>
Date: Mon Oct 2 17:56:58 2023 +0800
fs/jfs: Add check for negative db_l2nbperpage
[ Upstream commit 525b861a008143048535011f3816d407940f4bfa ]
l2nbperpage is log2(number of blks per page), and the minimum legal
value should be 0, not negative.
In the case of l2nbperpage being negative, an error will occur
when subsequently used as shift exponent.
Syzbot reported this bug:
UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:799:12
shift exponent -16777216 is negative
Reported-by: syzbot+debee9ab7ae2b34b0307@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=debee9ab7ae2b34b0307
Signed-off-by: Juntong Deng <juntong.deng@xxxxxxxxxxx>
Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index da4f9c3b714fe..a700950429c5f 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -180,7 +180,8 @@ int dbMount(struct inode *ipbmap)
bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
- if (bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE) {
+ if (bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE ||
+ bmp->db_l2nbperpage < 0) {
err = -EINVAL;
goto err_release_metapage;
}
