ksmbd: fix use-after-free bug in smb2_tree_disconect
authorNamjae Jeon <linkinjeon@kernel.org>
Thu, 28 Jul 2022 12:57:08 +0000 (21:57 +0900)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 17 Aug 2022 12:22:56 +0000 (14:22 +0200)
commit cf6531d98190fa2cf92a6d8bbc8af0a4740a223c upstream.

smb2_tree_disconnect() freed the struct ksmbd_tree_connect,
but it left the dangling pointer. It can be accessed
again under compound requests.

This bug can lead an oops looking something link:

[ 1685.468014 ] BUG: KASAN: use-after-free in ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd]
[ 1685.468068 ] Read of size 4 at addr ffff888102172180 by task kworker/1:2/4807
...
[ 1685.468130 ] Call Trace:
[ 1685.468132 ]  <TASK>
[ 1685.468135 ]  dump_stack_lvl+0x49/0x5f
[ 1685.468141 ]  print_report.cold+0x5e/0x5cf
[ 1685.468145 ]  ? ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd]
[ 1685.468157 ]  kasan_report+0xaa/0x120
[ 1685.468194 ]  ? ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd]
[ 1685.468206 ]  __asan_report_load4_noabort+0x14/0x20
[ 1685.468210 ]  ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd]
[ 1685.468222 ]  smb2_tree_disconnect+0x175/0x250 [ksmbd]
[ 1685.468235 ]  handle_ksmbd_work+0x30e/0x1020 [ksmbd]
[ 1685.468247 ]  process_one_work+0x778/0x11c0
[ 1685.468251 ]  ? _raw_spin_lock_irq+0x8e/0xe0
[ 1685.468289 ]  worker_thread+0x544/0x1180
[ 1685.468293 ]  ? __cpuidle_text_end+0x4/0x4
[ 1685.468297 ]  kthread+0x282/0x320
[ 1685.468301 ]  ? process_one_work+0x11c0/0x11c0
[ 1685.468305 ]  ? kthread_complete_and_exit+0x30/0x30
[ 1685.468309 ]  ret_from_fork+0x1f/0x30

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-17816
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/ksmbd/smb2pdu.c

index 4f92382..53f5db4 100644 (file)
@@ -2044,6 +2044,7 @@ int smb2_tree_disconnect(struct ksmbd_work *work)
 
        ksmbd_close_tree_conn_fds(work);
        ksmbd_tree_conn_disconnect(sess, tcon);
+       work->tcon = NULL;
        return 0;
 }