This is a note to let you know that I've just added the patch titled fs: jfs: fix shift-out-of-bounds in dbDiscardAG to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: fs-jfs-fix-shift-out-of-bounds-in-dbdiscardag.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 470fb25ead93508932036550ee51dba944b80453 Author: Hoi Pok Wu <wuhoipok@xxxxxxxxx> Date: Tue Oct 25 23:20:45 2022 +0800 fs: jfs: fix shift-out-of-bounds in dbDiscardAG [ Upstream commit 25e70c6162f207828dd405b432d8f2a98dbf7082 ] 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@xxxxxxxxx> Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index a46fa0f3db57..0ca1ad2610df 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -211,6 +211,11 @@ 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);