fs/jfs: Add validity check for db_maxag and db_agpref

Both db_maxag and db_agpref are used as the index of the
db_agfree array, but there is currently no validity check for
db_maxag and db_agpref, which can lead to errors.

The following is related bug reported by Syzbot:

UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:639:20
index 7936 is out of range for type 'atomic_t[128]'

Add checking that the values of db_maxag and db_agpref are valid
indexes for the db_agfree array.

Reported-by: syzbot+38e876a8aa44b7115c76@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=38e876a8aa44b7115c76
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
This commit is contained in:
Juntong Deng 2023-10-04 02:06:41 +08:00 committed by Dave Kleikamp
parent 525b861a00
commit 64933ab7b0

View file

@ -195,6 +195,12 @@ int dbMount(struct inode *ipbmap)
bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
if (bmp->db_maxag >= MAXAG || bmp->db_maxag < 0 ||
bmp->db_agpref >= MAXAG || bmp->db_agpref < 0) {
err = -EINVAL;
goto err_release_metapage;
}
bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);