netdev - Re: [Patch net v2] qrtr: orphan socket in qrtr

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Date:   Fri, 24 Jul 2020 09:57:33 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Cong Wang <xiyou.wangcong@...il.com>, netdev@...r.kernel.org
Cc:     syzbot+6720d64f31c081c2f708@...kaller.appspotmail.com,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [Patch net v2] qrtr: orphan socket in qrtr_release()



On 7/24/20 9:45 AM, Cong Wang wrote:
> We have to detach sock from socket in qrtr_release(),
> otherwise skb->sk may still reference to this socket
> when the skb is released in tun->queue, particularly
> sk->sk_wq still points to &sock->wq, which leads to
> a UAF.
> 
> Reported-and-tested-by: syzbot+6720d64f31c081c2f708@...kaller.appspotmail.com
> Fixes: 28fb4e59a47d ("net: qrtr: Expose tunneling endpoint to user space")
> Cc: Bjorn Andersson <bjorn.andersson@...aro.org>
> Cc: Eric Dumazet <eric.dumazet@...il.com>
> Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
> ---
>  net/qrtr/qrtr.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
> index 24a8c3c6da0d..300a104b9a0f 100644
> --- a/net/qrtr/qrtr.c
> +++ b/net/qrtr/qrtr.c
> @@ -1180,6 +1180,7 @@ static int qrtr_release(struct socket *sock)
>  		sk->sk_state_change(sk);
>  
>  	sock_set_flag(sk, SOCK_DEAD);
> +	sock_orphan(sk);
>  	sock->sk = NULL;
>  
>  	if (!sock_flag(sk, SOCK_ZAPPED))
> 

Reviewed-by: Eric Dumazet <edumazet@...gle.com>