Commit 24e90b9e authored by Hyunwoo Kim's avatar Hyunwoo Kim Committed by Paolo Abeni
Browse files

atm: Fix Use-After-Free in do_vcc_ioctl 



Because do_vcc_ioctl() accesses sk->sk_receive_queue
without holding a sk->sk_receive_queue.lock, it can
cause a race with vcc_recvmsg().
A use-after-free for skb occurs with the following flow.
```
do_vcc_ioctl() -> skb_peek()
vcc_recvmsg() -> skb_recv_datagram() -> skb_free_datagram()
```
Add sk->sk_receive_queue.lock to do_vcc_ioctl() to fix this issue.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarHyunwoo Kim <v4bel@theori.io>
Link: https://lore.kernel.org/r/20231209094210.GA403126@v4bel-B760M-AORUS-ELITE-AX


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent e307b5a8

net/atm/ioctl.c

+5 −2
Original line number Diff line number Diff line
@@ -73,14 +73,17 @@ static int do_vcc_ioctl(struct socket *sock, unsigned int cmd, 
	case SIOCINQ:

	{

		struct sk_buff *skb;

		int amount;



		if (sock->state != SS_CONNECTED) {

			error = -EINVAL;

			goto done;

		}

		spin_lock_irq(&sk->sk_receive_queue.lock);

		skb = skb_peek(&sk->sk_receive_queue);

		error = put_user(skb ? skb->len : 0,

				 (int __user *)argp) ? -EFAULT : 0;

		amount = skb ? skb->len : 0;

		spin_unlock_irq(&sk->sk_receive_queue.lock);

		error = put_user(amount, (int __user *)argp) ? -EFAULT : 0;

		goto done;

	}

	case ATM_SETSC: