On 8/19/26 10:54, Stefano Garzarella wrote:
>>>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>>>> index 622dbd046799..39c42ef016c3 100644
>>>> --- a/net/vmw_vsock/af_vsock.c
>>>> +++ b/net/vmw_vsock/af_vsock.c
>>>> @@ -1807,15 +1807,18 @@ static int vsock_connect(struct socket *sock,
>>>> struct sockaddr_unsized *addr,
>>>> timeout = schedule_timeout(timeout);
>>>> lock_sock(sk);
>>>>
>>>> - /* Connection established. Whatever happens to socket once we
>>>> + /* Connection (has been) established. Whatever happens to
>>>> socket once we
>>>> * release it, that's not connect()'s concern. No need to go
>>>> * into signal and timeout handling. Call it a day.
>>>> *
>>>> * Note that allowing to "reset" an already established socket
>>>> * here is racy and insecure.
>>>> */
>>>> - if (sk->sk_state == TCP_ESTABLISHED)
>>>> - break;
>>>> + if (sk->sk_state == TCP_ESTABLISHED ||
>>>> + sk->sk_state == TCP_CLOSING) {
>>>> + err = -sk->sk_err;
>>>> + goto out_wait;
>>>> + }
>>>>
>>>> /* If connection was _not_ established and a signal/timeout came
>>>> * to be, we want the socket's state reset. User space may want
>>>>
>>>> ?
>>>
>>> Yes, I like it better than mine. I confirmed it fixes the issue.
>>
>> Great, thanks.
>>
>>> If you don't mind, would you take the patch from here?
>>
>> Sure, no problem.
>>
>> Stefano, does this look good to you?
>
> Yep, thanks for helping here!
>
> My only doubt is if it makes sense to leave the `break` there, and add a
> similar check before resetting the socket, I mean something like this:
>
> err = sock_error(sk);
> if (err && sk->sk_state != TCP_ESTABLISHED &&
> sk->sk_state != TCP_CLOSING)) {
> sk->sk_state = TCP_CLOSE;
> sock->state = SS_UNCONNECTED;
> }
>
> Just to be a bit more defensive, but I don't have a strong opinion, your
> version is also fine.
>
>> And should any sk_err be consumed
>> here, too? (`err = sock_error(sk)` instead of `err = -sk->sk_err`)
>
> I'd stay with sock_error() to consume the error if it makes sense also
> for you.
Sure, one note: perhaps it's better to always return 0 on
TCP_ESTABLISHED/TCP_CLOSING? From connect()'s PoV these two states mean "we
did good, we connected to something for some time". Currently, even if the
connection was established, virtio_transport_recv_connected()'s
VIRTIO_VSOCK_OP_RW error handling may set sk_err = ENOBUFS, and connect()
would return that. Even though connect() itself was a success.
Anyway, here's a fix for the uaf:
https://lore.kernel.org/netdev/[email protected]/
It's incomplete, but I'm not sure how to follow up. Please see the
below---comment.
thanks,
Michal
