From: Hoi Pok Wu <wuhoipok@gmail.com>
Date: Tue, 25 Oct 2022 15:20:45 +0000 (+0800)
Subject: fs: jfs: fix shift-out-of-bounds in dbDiscardAG
X-Git-Tag: v6.6.17~5978^2~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=25e70c6162f207828dd405b432d8f2a98dbf7082;p=platform%2Fkernel%2Flinux-rpi.git

fs: jfs: fix shift-out-of-bounds in dbDiscardAG

This should be applied to most URSAN bugs found recently by syzbot,
by guarding the dbMount. As syzbot feeding rubbish into the bmap
descriptor.

Signed-off-by: Hoi Pok Wu <wuhoipok@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
---

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index e1cbfbb6..7658385 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -198,6 +198,11 @@ int dbMount(struct inode *ipbmap)
 		goto err_release_metapage;
 	}
 
+	if (((bmp->db_mapsize - 1) >> bmp->db_agl2size) > MAXAG) {
+		err = -EINVAL;
+		goto err_release_metapage;
+	}
+
 	for (i = 0; i < MAXAG; i++)
 		bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
 	bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);