This is a note to let you know that I've just added the patch titled
atm: Fix Use-After-Free in do_vcc_ioctl
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
atm-fix-use-after-free-in-do_vcc_ioctl.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a62aefbbfeb6a4f9f6ae53d2f1aaa1da17fa9b7b
Author: Hyunwoo Kim <v4bel@xxxxxxxxx>
Date: Sat Dec 9 04:42:10 2023 -0500
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 <v4bel@xxxxxxxxx>
Link: https://lore.kernel.org/r/20231209094210.GA403126@v4bel-B760M-AORUS-ELITE-AX
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/atm/ioctl.c b/net/atm/ioctl.c
index 2ff0e5e470e3d..38f7f164e4848 100644
--- a/net/atm/ioctl.c
+++ b/net/atm/ioctl.c
@@ -71,14 +71,17 @@ 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 SIOCGSTAMP: /* borrowed from IP */
