[PATCH next] fs/9p: fix uaf in in v9fs_stat2inode_dotl

Lizhi Xu
2024-02-02T12:16:53Z

The incorrect logical order of accessing the st object code in v9fs_fid_iget_dotl
is causing this uaf.

Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths")
Reported-and-tested-by: syzbot+7a3d75905ea1a830dbe5@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
---
fs/9p/vfs_inode_dotl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index ef9db3e03506..2b313fe7003e 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -78,11 +78,11 @@ struct inode *v9fs_fid_iget_dotl(struct super_block *sb, struct p9_fid *fid)

retval = v9fs_init_inode(v9ses, inode, &fid->qid,
st->st_mode, new_decode_dev(st->st_rdev));
+ v9fs_stat2inode_dotl(st, inode, 0);
kfree(st);
if (retval)
goto error;

- v9fs_stat2inode_dotl(st, inode, 0);
v9fs_set_netfs_context(inode);
v9fs_cache_inode_get_cookie(inode);
retval = v9fs_get_acl(inode, fid);
--
2.43.0