From: Juntong Deng juntong.deng@outlook.com
[ Upstream commit 64933ab7b04881c6c18b21ff206c12278341c72e ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/jfs/jfs_dmap.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index ee949e329c6e0..e2927d1f3d1d3 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -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);