Date:   Fri, 10 Mar 2023 12:50:23 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Fedor Pchelkin <pchelkin@ispras.ru>
Cc:     stable@vger.kernel.org, Marcel Holtmann <marcel@holtmann.org>,
        Nguyen Dinh Phi <phind.uet@gmail.com>,
        linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Alexey Khoroshilov <khoroshilov@ispras.ru>,
        lvc-project@linuxtesting.org,
        syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
Subject: Re: [PATCH 4.14/4.19/5.4/5.10/5.15 1/1] Bluetooth: hci_sock: purge
 socket queues in the destruct() callback
Message-ID: <ZAsZf4BvErezNB7Z@kroah.com>
References: <20230309181251.479447-1-pchelkin@ispras.ru>
 <20230309181251.479447-2-pchelkin@ispras.ru>
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On Thu, Mar 09, 2023 at 09:12:51PM +0300, Fedor Pchelkin wrote:
> From: Nguyen Dinh Phi <phind.uet@gmail.com>
> 
> commit 709fca500067524381e28a5f481882930eebac88 upstream.
> 
> The receive path may take the socket right before hci_sock_release(),
> but it may enqueue the packets to the socket queues after the call to
> skb_queue_purge(), therefore the socket can be destroyed without clear
> its queues completely.
> 
> Moving these skb_queue_purge() to the hci_sock_destruct() will fix this
> issue, because nothing is referencing the socket at this point.
> 
> Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
> Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> ---
>  net/bluetooth/hci_sock.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
> index f1128c2134f0..3f92a21cabe8 100644
> --- a/net/bluetooth/hci_sock.c
> +++ b/net/bluetooth/hci_sock.c
> @@ -888,10 +888,6 @@ static int hci_sock_release(struct socket *sock)
>  	}
>  
>  	sock_orphan(sk);
> -
> -	skb_queue_purge(&sk->sk_receive_queue);
> -	skb_queue_purge(&sk->sk_write_queue);
> -
>  	release_sock(sk);
>  	sock_put(sk);
>  	return 0;
> @@ -2012,6 +2008,12 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname,
>  	return err;
>  }
>  
> +static void hci_sock_destruct(struct sock *sk)
> +{
> +	skb_queue_purge(&sk->sk_receive_queue);
> +	skb_queue_purge(&sk->sk_write_queue);
> +}
> +
>  static const struct proto_ops hci_sock_ops = {
>  	.family		= PF_BLUETOOTH,
>  	.owner		= THIS_MODULE,
> @@ -2065,6 +2067,7 @@ static int hci_sock_create(struct net *net, struct socket *sock, int protocol,
>  
>  	sock->state = SS_UNCONNECTED;
>  	sk->sk_state = BT_OPEN;
> +	sk->sk_destruct = hci_sock_destruct;
>  
>  	bt_sock_link(&hci_sk_list, sk);
>  	return 0;
> -- 
> 2.34.1
> 

Now queued up, thanks.

greg k-h