Commit ff923ebb authored Dec 29, 2023 by Hyunwoo Kim Committed by Ziyang Xuan Dec 29, 2023

Bluetooth: af_bluetooth: Fix Use-After-Free in bt_sock_recvmsg

mainline inclusion
from mainline-v6.7-rc7
commit 2e07e8348ea454615e268222ae3fc240421be768
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8RXOD
CVE: CVE-2023-51779

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2e07e8348ea454615e268222ae3fc240421be768



--------------------------------

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@vger.kernel.org
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Conflicts:
	net/bluetooth/af_bluetooth.c
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>

parent ee181715

net/bluetooth/af_bluetooth.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -263,11 +263,14 @@ 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, noblock, &err);
		if (!skb) {
		if (sk->sk_shutdown & RCV_SHUTDOWN)
		return 0;
		err = 0;

		release_sock(sk);
		return err;
		}

		@@ -293,6 +296,8 @@ 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;