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From: Namjae Jeon <linkinjeon@kernel.org>
To: linux-cifs@vger.kernel.org
Cc: smfrench@gmail.com, hyc.lee@gmail.com, senozhatsky@chromium.org,
	gregkh@linuxfoundation.org, Namjae Jeon <linkinjeon@kernel.org>,
	stable@vger.kernel.org, zdi-disclosures@trendmicro.com
Subject: [PATCH v2 2/5] ksmbd: fix use-after-free bug in smb2_tree_disconect
Date: Thu, 28 Jul 2022 22:49:43 +0900	[thread overview]
Message-ID: <20220728134946.7603-2-linkinjeon@kernel.org> (raw)
In-Reply-To: <20220728134946.7603-1-linkinjeon@kernel.org>

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>
---
 v2:
   - add missing fixes and stable tags.

 fs/ksmbd/smb2pdu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 41ef076af072..7ecb6d87ae3e 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -2057,6 +2057,7 @@ 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;
 }
 
-- 
2.25.1


  reply	other threads:[~2022-07-28 13:50 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-28 13:49 [PATCH v2 1/5] ksmbd: fix memory leak in smb2_handle_negotiate Namjae Jeon
2022-07-28 13:49 ` Namjae Jeon [this message]
2022-07-28 13:49 ` [PATCH v2 3/5] ksmbd: prevent out of bound read for SMB2_WRITE Namjae Jeon
2022-07-28 13:49 ` [PATCH v2 4/5] ksmbd: prevent out of bound read for SMB2_TREE_CONNNECT Namjae Jeon
2022-07-28 13:49 ` [PATCH v2 5/5] ksmbd: fix heap-based overflow in set_ntacl_dacl() Namjae Jeon

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