FAILED: patch "[PATCH] Bluetooth: af_bluetooth: Fix Use-After-Free in" failed to apply to 5.15-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 2e07e8348ea454615e268222ae3fc240421be768
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023122842-probation-retiree-3f3d@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

2e07e8348ea4 ("Bluetooth: af_bluetooth: Fix Use-After-Free in bt_sock_recvmsg")
f4b41f062c42 ("net: remove noblock parameter from skb_recv_datagram()")
42bf50a1795a ("can: isotp: support MSG_TRUNC flag when reading from socket")
30ffd5332e06 ("can: isotp: return -EADDRNOTAVAIL when reading from unbound socket")
c5755214623d ("mctp: tests: Add key state tests")
62a2b005c6d6 ("mctp: tests: Rename FL_T macro to FL_TO")
1e5e9250d422 ("mctp: Add input reassembly tests")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 2e07e8348ea454615e268222ae3fc240421be768 Mon Sep 17 00:00:00 2001
From: Hyunwoo Kim <v4bel@xxxxxxxxx>
Date: Sat, 9 Dec 2023 05:55:18 -0500
Subject: [PATCH] Bluetooth: af_bluetooth: Fix Use-After-Free in
 bt_sock_recvmsg

This can cause a race with bt_sock_ioctl() because
bt_sock_recvmsg() gets the skb from sk->sk_receive_queue
and then frees it without holding lock_sock.
A use-after-free for a skb occurs with the following flow.
```
bt_sock_recvmsg() -> skb_recv_datagram() -> skb_free_datagram()
bt_sock_ioctl() -> skb_peek()
```
Add lock_sock to bt_sock_recvmsg() to fix this issue.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Hyunwoo Kim <v4bel@xxxxxxxxx>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>

diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index 336a76165454..b93464ac3517 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -309,11 +309,14 @@ int bt_sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 	if (flags & MSG_OOB)
 		return -EOPNOTSUPP;
 
+	lock_sock(sk);
+
 	skb = skb_recv_datagram(sk, flags, &err);
 	if (!skb) {
 		if (sk->sk_shutdown & RCV_SHUTDOWN)
-			return 0;
+			err = 0;
 
+		release_sock(sk);
 		return err;
 	}
 
@@ -343,6 +346,8 @@ int bt_sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 
 	skb_free_datagram(sk, skb);
 
+	release_sock(sk);
+
 	if (flags & MSG_TRUNC)
 		copied = skblen;