From: Hyunwoo Kim <v4bel@theori.io>
To: pabeni@redhat.com, davem@davemloft.net, edumazet@google.com,
kuniyu@amazon.com
Cc: v4bel@theori.io, imv4bel@gmail.com, kuba@kernel.org,
horms@kernel.org, dhowells@redhat.com, lukas.bulwahn@gmail.com,
mkl@pengutronix.de, netdev@vger.kernel.org
Subject: [PATCH v3] appletalk: Fix Use-After-Free in atalk_ioctl
Date: Tue, 12 Dec 2023 23:10:56 -0500 [thread overview]
Message-ID: <20231213041056.GA519680@v4bel-B760M-AORUS-ELITE-AX> (raw)
Because atalk_ioctl() accesses sk->sk_receive_queue
without holding a sk->sk_receive_queue.lock, it can
cause a race with atalk_recvmsg().
A use-after-free for skb occurs with the following flow.
```
atalk_ioctl() -> skb_peek()
atalk_recvmsg() -> skb_recv_datagram() -> skb_free_datagram()
```
Add sk->sk_receive_queue.lock to atalk_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: Delete old comments
---
net/appletalk/ddp.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index 9ba04a69ec2a..a852ec093fa8 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1775,15 +1775,14 @@ static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
break;
}
case TIOCINQ: {
- /*
- * These two are safe on a single CPU system as only
- * user tasks fiddle here
- */
- struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
+ struct sk_buff *skb;
long amount = 0;
+ spin_lock_irq(&sk->sk_receive_queue.lock);
+ skb = skb_peek(&sk->sk_receive_queue);
if (skb)
amount = skb->len - sizeof(struct ddpehdr);
+ spin_unlock_irq(&sk->sk_receive_queue.lock);
rc = put_user(amount, (int __user *)argp);
break;
}
--
2.25.1
next reply other threads:[~2023-12-13 4:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-13 4:10 Hyunwoo Kim [this message]
2023-12-14 11:10 ` [PATCH v3] appletalk: Fix Use-After-Free in atalk_ioctl patchwork-bot+netdevbpf
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