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authorHyunwoo Kim <v4bel@theori.io>2023-12-12 23:10:56 -0500
committerPaolo Abeni <pabeni@redhat.com>2023-12-14 12:02:45 +0100
commit189ff16722ee36ced4d2a2469d4ab65a8fee4198 (patch)
tree2e2350fffda48970b46f6d8736f9b16f0145712d /net
parente23c0d21ce9234fbc31ece35663ababbb83f9347 (diff)
appletalk: Fix Use-After-Free in atalk_ioctl
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> Link: https://lore.kernel.org/r/20231213041056.GA519680@v4bel-B760M-AORUS-ELITE-AX Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
-rw-r--r--net/appletalk/ddp.c9
1 files 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;
}