Re: [PATCH v2] net/rose: Fix Use-After-Free in rose_ioctl
From: Eric Dumazet <edumazet@google.com>
Date: 2023-12-06 10:33:28
Also in:
linux-hams
On Wed, Dec 6, 2023 at 5:13 AM Hyunwoo Kim [off-list ref] wrote:
Because rose_ioctl() accesses sk->sk_receive_queue without holding a sk->sk_receive_queue.lock, it can cause a race with rose_accept(). A use-after-free for skb occurs with the following flow.rose_ioctl() -> skb_peek() rose_accept() -> skb_dequeue() -> kfree_skb()Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
Please add a Fixes: tag
quoted hunk ↗ jump to hunk
Signed-off-by: Hyunwoo Kim <redacted> --- v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock. --- net/rose/af_rose.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index 0cc5a4e19900..841c238de222 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c@@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) struct sk_buff *skb; long amount = 0L; /* These two are safe on a single CPU system as only user tasks fiddle here */ + spin_lock(&sk->sk_receive_queue.lock);
You need interrupt safety here. sk_receive_queue can be fed from interrupt, that would potentially deadlock.
if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
amount = skb->len;
+ spin_unlock(&sk->sk_receive_queue.lock);
return put_user(amount, (unsigned int __user *) argp);
}
--
2.25.1