From: Liu Shixin via Jfs-discussion jfs-discussion@lists.sourceforge.net
[ 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@syzkaller.appspotmail.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Liu Shixin liushixin2@huawei.com Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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; }