diff options
| author | Namjae Jeon <linkinjeon@kernel.org> | 2023-10-04 18:25:01 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-10-10 22:00:45 +0200 |
| commit | a2ca5fd3dbcc665e1169044fa0c9e3eba779202b (patch) | |
| tree | fc097ee2a90bd4f7af6861438887abbc07cced34 | |
| parent | 64301a9354626d1afb23a72720a99190d9157358 (diff) | |
ksmbd: fix race condition between session lookup and expire
commit 53ff5cf89142b978b1a5ca8dc4d4425e6a09745f upstream.
Thread A + Thread B
ksmbd_session_lookup | smb2_sess_setup
sess = xa_load |
|
| xa_erase(&conn->sessions, sess->id);
|
| ksmbd_session_destroy(sess) --> kfree(sess)
|
// UAF! |
sess->last_active = jiffies |
+
This patch add rwsem to fix race condition between ksmbd_session_lookup
and ksmbd_expire_session.
Reported-by: luosili <rootlab@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/smb/server/connection.c | 2 | ||||
| -rw-r--r-- | fs/smb/server/connection.h | 1 | ||||
| -rw-r--r-- | fs/smb/server/mgmt/user_session.c | 10 |
3 files changed, 10 insertions, 3 deletions
diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index e1d2be19cddfa..ff97cad8d5b45 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -84,6 +84,8 @@ struct ksmbd_conn *ksmbd_conn_alloc(void) spin_lock_init(&conn->llist_lock); INIT_LIST_HEAD(&conn->lock_list); + init_rwsem(&conn->session_lock); + down_write(&conn_list_lock); list_add(&conn->conns_list, &conn_list); up_write(&conn_list_lock); diff --git a/fs/smb/server/connection.h b/fs/smb/server/connection.h index ad8dfaa48ffb3..335fdd714d595 100644 --- a/fs/smb/server/connection.h +++ b/fs/smb/server/connection.h @@ -50,6 +50,7 @@ struct ksmbd_conn { struct nls_table *local_nls; struct unicode_map *um; struct list_head conns_list; + struct rw_semaphore session_lock; /* smb session 1 per user */ struct xarray sessions; unsigned long last_active; diff --git a/fs/smb/server/mgmt/user_session.c b/fs/smb/server/mgmt/user_session.c index ea4b56d570fbb..cf6621e21ba36 100644 --- a/fs/smb/server/mgmt/user_session.c +++ b/fs/smb/server/mgmt/user_session.c @@ -183,7 +183,7 @@ static void ksmbd_expire_session(struct ksmbd_conn *conn) unsigned long id; struct ksmbd_session *sess; - down_write(&sessions_table_lock); + down_write(&conn->session_lock); xa_for_each(&conn->sessions, id, sess) { if (sess->state != SMB2_SESSION_VALID || time_after(jiffies, @@ -194,7 +194,7 @@ static void ksmbd_expire_session(struct ksmbd_conn *conn) continue; } } - up_write(&sessions_table_lock); + up_write(&conn->session_lock); } int ksmbd_session_register(struct ksmbd_conn *conn, @@ -236,7 +236,9 @@ void ksmbd_sessions_deregister(struct ksmbd_conn *conn) } } } + up_write(&sessions_table_lock); + down_write(&conn->session_lock); xa_for_each(&conn->sessions, id, sess) { unsigned long chann_id; struct channel *chann; @@ -253,7 +255,7 @@ void ksmbd_sessions_deregister(struct ksmbd_conn *conn) ksmbd_session_destroy(sess); } } - up_write(&sessions_table_lock); + up_write(&conn->session_lock); } struct ksmbd_session *ksmbd_session_lookup(struct ksmbd_conn *conn, @@ -261,9 +263,11 @@ struct ksmbd_session *ksmbd_session_lookup(struct ksmbd_conn *conn, { struct ksmbd_session *sess; + down_read(&conn->session_lock); sess = xa_load(&conn->sessions, id); if (sess) sess->last_active = jiffies; + up_read(&conn->session_lock); return sess; } |