From: Hyunwoo Kim Date: Sat, 9 Dec 2023 09:42:10 +0000 (-0500) Subject: atm: Fix Use-After-Free in do_vcc_ioctl X-Git-Tag: v6.6.8~130 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=531fd46f92895bcdc41bedd12533266c397196da;p=platform%2Fkernel%2Flinux-starfive.git atm: Fix Use-After-Free in do_vcc_ioctl [ Upstream commit 24e90b9e34f9e039f56b5f25f6e6eb92cdd8f4b3 ] 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: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Hyunwoo Kim Link: https://lore.kernel.org/r/20231209094210.GA403126@v4bel-B760M-AORUS-ELITE-AX Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- diff --git a/net/atm/ioctl.c b/net/atm/ioctl.c index 838ebf0..f81f8d5 100644 --- a/net/atm/ioctl.c +++ b/net/atm/ioctl.c @@ -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: