Re: [PATCH V2] fs: jfs: fix shift-out-of-bounds in dbDiscardAG

From: Dave Kleikamp
Date: Thu Oct 27 2022 - 18:36:27 EST


Applied.

Thanks,
Shaggy

On 10/25/22 10:20AM, Hoi Pok Wu wrote:
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>
---
V1->2: guarding the corrupted data structure from dbMount instead
fs/jfs/jfs_dmap.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index e1cbfbb60303..765838578a72 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);