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Message-ID: <20231209090509.GA401342@v4bel-B760M-AORUS-ELITE-AX>
Date: Sat, 9 Dec 2023 04:05:09 -0500
From: Hyunwoo Kim <v4bel@...ori.io>
To: davem@...emloft.net, kuba@...nel.org
Cc: v4bel@...ori.io, imv4bel@...il.com, edumazet@...gle.com,
pabeni@...hat.com, netdev@...r.kernel.org
Subject: [PATCH net v2] 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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Hyunwoo Kim <v4bel@...ori.io>
---
v1 -> v2: Change the code style
---
net/atm/ioctl.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/atm/ioctl.c b/net/atm/ioctl.c
index 838ebf0cabbf..b7684abcf458 100644
--- a/net/atm/ioctl.c
+++ b/net/atm/ioctl.c
@@ -72,15 +72,18 @@ static int do_vcc_ioctl(struct socket *sock, unsigned int cmd,
goto done;
case SIOCINQ:
{
+ long amount;
struct sk_buff *skb;
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:
--
2.25.1
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