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 6.1-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-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1f8fa87d7da5c893e37b94ca4e63699fff68d8a8
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 e9d075cbd71ad..ee949e329c6e0 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;
}
