This is a note to let you know that I've just added the patch titled
Bluetooth: af_bluetooth: Fix Use-After-Free in bt_sock_recvmsg
to the 6.6-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-af_bluetooth-fix-use-after-free-in-bt_sock_recvmsg.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2e07e8348ea454615e268222ae3fc240421be768 Mon Sep 17 00:00:00 2001
From: Hyunwoo Kim <v4bel@xxxxxxxxx>
Date: Sat, 9 Dec 2023 05:55:18 -0500
Subject: Bluetooth: af_bluetooth: Fix Use-After-Free in bt_sock_recvmsg
From: Hyunwoo Kim <v4bel@xxxxxxxxx>
commit 2e07e8348ea454615e268222ae3fc240421be768 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/bluetooth/af_bluetooth.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -309,11 +309,14 @@ int bt_sock_recvmsg(struct socket *sock,
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,
skb_free_datagram(sk, skb);
+ release_sock(sk);
+
if (flags & MSG_TRUNC)
copied = skblen;
Patches currently in stable-queue which might be from v4bel@xxxxxxxxx are
queue-6.6/bluetooth-af_bluetooth-fix-use-after-free-in-bt_sock_recvmsg.patch
