Re: [PATCH] Bluetooth: check l2cap pending status before sending l2cap connect request

["Gustavo F. Padovan" <gustavo@padovan.org>]

Hi Andrei,

* Emeltchenko Andrei <Andrei.Emeltchenko.news@gmail.com> [2010-06-16 15:52:05 +0300]:

> From: Andrei Emeltchenko <andrei.emeltchenko@nokia.com>
> 
> Due to race condition in L2CAP state machine L2CAP Connection Request
> may be sent twice for SDP with the same source channel id. Problems
> reported connecting to Apple products, some carkit, Blackberry phones.
> 
> ...
> 2010-06-07 21:18:03.651031 < ACL data: handle 1 flags 0x02 dlen 12
>     L2CAP(s): Connect req: psm 1 scid 0x0040
> 2010-06-07 21:18:03.653473 > HCI Event: Number of Completed Packets (0x13) plen 5
>     handle 1 packets 1
> 2010-06-07 21:18:03.653808 > HCI Event: Auth Complete (0x06) plen 3
>     status 0x00 handle 1
> 2010-06-07 21:18:03.653869 < ACL data: handle 1 flags 0x02 dlen 12
>     L2CAP(s): Connect req: psm 1 scid 0x0040
> ...
> 
> Patch uses L2CAP_CONF_CONNECT_PEND flag to mark that L2CAP Connection
> Request has been sent.
> 
> Modified version of Ville Tervo patch.
> 
> Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@nokia.com>
> ---
>  net/bluetooth/l2cap.c |   11 +++++++++--
>  1 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
> index fc81acb..1ed51ad 100644
> --- a/net/bluetooth/l2cap.c
> +++ b/net/bluetooth/l2cap.c
> @@ -387,13 +387,16 @@ static void l2cap_do_start(struct sock *sk)
>  		if (!(conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE))
>  			return;
>  
> -		if (l2cap_check_security(sk)) {
> +		if (l2cap_check_security(sk) &&
> +				! l2cap_pi(sk)->conf_state &
> +				L2CAP_CONF_CONNECT_PEND) {

This is wrong, you have to add parentheses here:
	!(l2cap_pi(sk)->conf_state & L2CAP_CONF_CONNECT_PEND)

>  			struct l2cap_conn_req req;
>  			req.scid = cpu_to_le16(l2cap_pi(sk)->scid);
>  			req.psm  = l2cap_pi(sk)->psm;
>  
>  			l2cap_pi(sk)->ident = l2cap_get_ident(conn);
>  
> +			l2cap_pi(sk)->conf_state |= L2CAP_CONF_CONNECT_PEND;
>  			l2cap_send_cmd(conn, l2cap_pi(sk)->ident,
>  					L2CAP_CONN_REQ, sizeof(req), &req);
>  		}
> @@ -441,13 +444,16 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
>  		}
>  
>  		if (sk->sk_state == BT_CONNECT) {
> -			if (l2cap_check_security(sk)) {
> +			if (l2cap_check_security(sk) &&
> +					! l2cap_pi(sk)->conf_state &
> +					L2CAP_CONF_CONNECT_PEND) {

Here too.

>  				struct l2cap_conn_req req;
>  				req.scid = cpu_to_le16(l2cap_pi(sk)->scid);
>  				req.psm  = l2cap_pi(sk)->psm;
>  
>  				l2cap_pi(sk)->ident = l2cap_get_ident(conn);
>  
> +				l2cap_pi(sk)->conf_state |= L2CAP_CONF_CONNECT_PEND;
>  				l2cap_send_cmd(conn, l2cap_pi(sk)->ident,
>  					L2CAP_CONN_REQ, sizeof(req), &req);
>  			}
> @@ -3828,6 +3834,7 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
>  
>  				l2cap_pi(sk)->ident = l2cap_get_ident(conn);
>  
> +				l2cap_pi(sk)->conf_state |= L2CAP_CONF_CONNECT_PEND;
>  				l2cap_send_cmd(conn, l2cap_pi(sk)->ident,
>  					L2CAP_CONN_REQ, sizeof(req), &req);
>  			} else {
> -- 
> 1.7.0.4

Otherwise the patch seem fine to me.
> 
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-- 
Gustavo F. Padovan
http://padovan.org