Patch "Bluetooth: fix dangling sco_conn and use-after-free in sco_sock_timeout" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    Bluetooth: fix dangling sco_conn and use-after-free in sco_sock_timeout

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bluetooth-fix-dangling-sco_conn-and-use-after-free-i.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d4f744d39335f5984e87b6b995b4c9129e57ced1
Author: Ying Hsu <yinghsu@xxxxxxxxxxxx>
Date:   Sat Mar 26 07:09:28 2022 +0000

    Bluetooth: fix dangling sco_conn and use-after-free in sco_sock_timeout
    
    [ Upstream commit 7aa1e7d15f8a5b65f67bacb100d8fc033b21efa2 ]
    
    Connecting the same socket twice consecutively in sco_sock_connect()
    could lead to a race condition where two sco_conn objects are created
    but only one is associated with the socket. If the socket is closed
    before the SCO connection is established, the timer associated with the
    dangling sco_conn object won't be canceled. As the sock object is being
    freed, the use-after-free problem happens when the timer callback
    function sco_sock_timeout() accesses the socket. Here's the call trace:
    
    dump_stack+0x107/0x163
    ? refcount_inc+0x1c/
    print_address_description.constprop.0+0x1c/0x47e
    ? refcount_inc+0x1c/0x7b
    kasan_report+0x13a/0x173
    ? refcount_inc+0x1c/0x7b
    check_memory_region+0x132/0x139
    refcount_inc+0x1c/0x7b
    sco_sock_timeout+0xb2/0x1ba
    process_one_work+0x739/0xbd1
    ? cancel_delayed_work+0x13f/0x13f
    ? __raw_spin_lock_init+0xf0/0xf0
    ? to_kthread+0x59/0x85
    worker_thread+0x593/0x70e
    kthread+0x346/0x35a
    ? drain_workqueue+0x31a/0x31a
    ? kthread_bind+0x4b/0x4b
    ret_from_fork+0x1f/0x30
    
    Link: https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
    Reported-by: syzbot+2bef95d3ab4daa10155b@xxxxxxxxxxxxxxxxxxxxxxxxx
    Fixes: e1dee2c1de2b ("Bluetooth: fix repeated calls to sco_sock_kill")
    Signed-off-by: Ying Hsu <yinghsu@xxxxxxxxxxxx>
    Reviewed-by: Joseph Hwang <josephsih@xxxxxxxxxxxx>
    Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 6e047e178c0a..c7b43c75677f 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -575,19 +575,24 @@ static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen
 	    addr->sa_family != AF_BLUETOOTH)
 		return -EINVAL;
 
-	if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND)
-		return -EBADFD;
+	lock_sock(sk);
+	if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND) {
+		err = -EBADFD;
+		goto done;
+	}
 
-	if (sk->sk_type != SOCK_SEQPACKET)
-		return -EINVAL;
+	if (sk->sk_type != SOCK_SEQPACKET) {
+		err = -EINVAL;
+		goto done;
+	}
 
 	hdev = hci_get_route(&sa->sco_bdaddr, &sco_pi(sk)->src, BDADDR_BREDR);
-	if (!hdev)
-		return -EHOSTUNREACH;
+	if (!hdev) {
+		err = -EHOSTUNREACH;
+		goto done;
+	}
 	hci_dev_lock(hdev);
 
-	lock_sock(sk);
-
 	/* Set destination address and psm */
 	bacpy(&sco_pi(sk)->dst, &sa->sco_bdaddr);