[PATCH 4.19 31/71] ceph: fix use-after-free for fsc->mdsc

Greg Kroah-Hartman
2020-08-24T09:14:56Z

From: Xiubo Li <xiubli@redhat.com>

[ Upstream commit a7caa88f8b72c136f9a401f498471b8a8e35370d ]

If the ceph_mdsc_init() fails, it will free the mdsc already.

Reported-by: syzbot+b57f46d8d6ea51960b8c@syzkaller.appspotmail.com
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ceph/mds_client.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index a2e903203bf9f..0fa14d8b9c64c 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3682,7 +3682,6 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
return -ENOMEM;
}

- fsc->mdsc = mdsc;
init_completion(&mdsc->safe_umount_waiters);
init_waitqueue_head(&mdsc->session_close_wq);
INIT_LIST_HEAD(&mdsc->waiting_for_map);
@@ -3723,6 +3722,8 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)

strscpy(mdsc->nodename, utsname()->nodename,
sizeof(mdsc->nodename));
+
+ fsc->mdsc = mdsc;
return 0;
}

--
2.25.1