phonet/pep: fix racy skb_queue_empty() use
The receive queues are protected by their respective spin-lock, not
the socket lock. This could lead to skb_peek() unexpectedly
returning NULL or a pointer to an already dequeued socket buffer.
Fixes: 9641458d3e
("Phonet: Pipe End Point for Phonet Pipes protocol")
Signed-off-by: Rémi Denis-Courmont <courmisch@gmail.com>
Link: https://lore.kernel.org/r/20240218081214.4806-2-remi@remlab.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
parent
3b2d9bc4d4
commit
7d2a894d7f
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@ -917,6 +917,37 @@ static int pep_sock_enable(struct sock *sk, struct sockaddr *addr, int len)
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return 0;
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return 0;
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}
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}
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static unsigned int pep_first_packet_length(struct sock *sk)
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{
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struct pep_sock *pn = pep_sk(sk);
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struct sk_buff_head *q;
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struct sk_buff *skb;
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unsigned int len = 0;
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bool found = false;
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if (sock_flag(sk, SOCK_URGINLINE)) {
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q = &pn->ctrlreq_queue;
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spin_lock_bh(&q->lock);
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skb = skb_peek(q);
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if (skb) {
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len = skb->len;
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found = true;
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}
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spin_unlock_bh(&q->lock);
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}
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if (likely(!found)) {
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q = &sk->sk_receive_queue;
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spin_lock_bh(&q->lock);
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skb = skb_peek(q);
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if (skb)
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len = skb->len;
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spin_unlock_bh(&q->lock);
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}
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return len;
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}
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static int pep_ioctl(struct sock *sk, int cmd, int *karg)
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static int pep_ioctl(struct sock *sk, int cmd, int *karg)
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{
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{
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struct pep_sock *pn = pep_sk(sk);
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struct pep_sock *pn = pep_sk(sk);
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@ -929,15 +960,7 @@ static int pep_ioctl(struct sock *sk, int cmd, int *karg)
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break;
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break;
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}
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}
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lock_sock(sk);
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*karg = pep_first_packet_length(sk);
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if (sock_flag(sk, SOCK_URGINLINE) &&
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!skb_queue_empty(&pn->ctrlreq_queue))
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*karg = skb_peek(&pn->ctrlreq_queue)->len;
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else if (!skb_queue_empty(&sk->sk_receive_queue))
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*karg = skb_peek(&sk->sk_receive_queue)->len;
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else
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*karg = 0;
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release_sock(sk);
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ret = 0;
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ret = 0;
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break;
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break;
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