net/rose: Fix Use-After-Free in rose_ioctl

Because rose_ioctl() accesses sk->sk_receive_queue without holding a sk->sk_receive_queue.lock, it can cause a race with rose_accept(). A use-after-free for skb occurs with the following flow. ``` rose_ioctl() -> skb_peek() rose_accept() -> skb_dequeue() -> kfree_skb() ``` Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue. Fixes: 1da177e ("Linux-2.6.12-rc2") Signed-off-by: Hyunwoo Kim <[email protected]> Link: https://lore.kernel.org/r/20231209100538.GA407321@v4bel-B760M-AORUS-ELITE-AX Signed-off-by: Paolo Abeni <[email protected]>
torvalds · Dec 12, 2023 · 810c38a · 810c38a
1 parent 24e90b9
commit 810c38a
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
@@ -1315,9 +1315,11 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	case TIOCINQ: {
 		struct sk_buff *skb;
 		long amount = 0L;
-		/* These two are safe on a single CPU system as only user tasks fiddle here */
+
+		spin_lock_irq(&sk->sk_receive_queue.lock);
 		if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
 			amount = skb->len;
+		spin_unlock_irq(&sk->sk_receive_queue.lock);
 		return put_user(amount, (unsigned int __user *) argp);
 	}