Re: [PATCH] Bluetooth: Fix use after free in l2cap_chan_timeout

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

Hello.

On 3/18/2015 2:59 PM, Harish Jenny K N wrote:

> There is a potential use after free in bt_sock_poll when a
> socket gets killed without getting unlinked from accept_q.
> Hence added code to unlink from accpept_q by calling teardown
> before freeing the socket for channel type L2CAP_CHAN_CONN_ORIENTED.

> Signed-off-by: Harish Jenny K N <harish_kandiga@mentor.com>
> ---
>   net/bluetooth/l2cap_core.c |    5 +++++
>   1 file changed, 5 insertions(+)

> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 6ba33f9..3c3421e 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -415,6 +415,11 @@ static void l2cap_chan_timeout(struct work_struct *work)
>
>   	l2cap_chan_close(chan, reason);
>
> +	if (((chan->state == BT_CONNECTED) || (chan->state == BT_CONFIG)) &&

    Note that parens around == are unnecessary.

> +	    chan->chan_type == L2CAP_CHAN_CONN_ORIENTED) {
> +		chan->ops->teardown(chan, 0);
> +	}
> +
[...]

WBR, Sergei