From: Liu Shixin via Jfs-discussion <jfs-discussion@xxxxxxxxxxxxxxxxxxxxx>
[ Upstream commit fad376fce0af58deebc5075b8539dc05bf639af3 ]
As a shift exponent, db_agl2size can not be less than 0. Add the missing
check to fix the shift-out-of-bounds bug reported by syzkaller:
UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:2227:15
shift exponent -744642816 is negative
Reported-by: syzbot+0be96567042453c0c820@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/jfs/jfs_dmap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 765838578a722..a3eb1e8269477 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -193,7 +193,8 @@ int dbMount(struct inode *ipbmap)
bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
- if (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG) {
+ if (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG ||
+ bmp->db_agl2size < 0) {
err = -EINVAL;
goto err_release_metapage;
}
--
2.39.2
