| Message ID | 20231209094210.GA403126@v4bel-B760M-AORUS-ELITE-AX (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 24e90b9e34f9e039f56b5f25f6e6eb92cdd8f4b3 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v3] atm: Fix Use-After-Free in do_vcc_ioctl | expand |
Hello: This patch was applied to netdev/net.git (main) by Paolo Abeni <pabeni@redhat.com>: On Sat, 9 Dec 2023 04:42:10 -0500 you wrote: > 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. > > [...] Here is the summary with links: - [net,v3] atm: Fix Use-After-Free in do_vcc_ioctl https://git.kernel.org/netdev/net/c/24e90b9e34f9 You are awesome, thank you!
diff --git a/net/atm/ioctl.c b/net/atm/ioctl.c index 838ebf0cabbf..f81f8d56f5c0 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:
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 <v4bel@theori.io> --- v1 -> v2: Change the code style v2 -> v3: Change to 'int amount' --- net/atm/ioctl.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)