[PATCH/RFC] improve overlap detection and handling for P2P PBC

Vitaly Wool vitalywool at gmail.com
Tue Nov 29 12:11:05 EST 2011


Looks like tabs have been messed up here but I hope it's okay since this is
an RFC anyway. If it's fine, I'll make a respin with tabs unexpanded.

Thanks,
   Vitaly
Den 29 nov 2011 17:36 skrev "Vitaly Wool" <vitalywool at gmail.com>:

> Hi,
>
> I've been struggling to get my prototype P2P device to work with Samsung
> Galaxy SII. The connection establishment kept failing with WPS_FAILURE and
> it turned out to be due to overlap detected:
>
> 01-03 01:27:26.140 E/wpa_supplicant( 2455): WPS: Requested UUID -
> hexdump(len=16): 22 21 02 03 04 05 06 07 08 09 1a 1b 1c 1d 1e 1f
> 01-03 01:27:26.140 D/wpa_supplicant( 2455): WPS: Consider PBC session with
> 06:46:65:d3:4a:54
> 01-03 01:27:26.140 E/wpa_supplicant( 2455): WPS: UUID-E - hexdump(len=16):
> 22 21 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
> 01-03 01:27:26.140 D/wpa_supplicant( 2455): WPS: New Enrollee
> 01-03 01:27:26.140 D/wpa_supplicant( 2455): WPS: 2 active PBC session(s)
> found
> 01-03 01:27:26.140 D/wpa_supplicant( 2455): WPS: PBC overlap - deny PBC
> negotiation
>
> So Galaxy changes UUID for PBC negotiation but the thing is, it could have
> been considered to be the same session because the MAC address is the same.
> There is a mechanism to do so for P2P connections in wpa_supplicant but it
> doesn't work because P2P MAC address is not passed over
> to wps_registrar_skip_overlap(). This patch adds that and also fixes the
> PBC session removal after the negotiation (the current version leaves the
> session in the list if it doesn't match UUID, I suggest that we remove all
> sessions for the given MAC).
>
> diff --git a/src/wps/wps_registrar.c b/src/wps/wps_registrar.c
> index 4a49197..eed29e2 100644
> --- a/src/wps/wps_registrar.c
> +++ b/src/wps/wps_registrar.c
> @@ -310,13 +310,16 @@ static void wps_registrar_add_pbc_session(struct
> wps_registrar *reg,
>
>
>  static void wps_registrar_remove_pbc_session(struct wps_registrar *reg,
> -     const u8 *uuid_e)
> +     const u8 *uuid_e,
> +     const u8 *p2p_dev_addr)
>  {
>   struct wps_pbc_session *pbc, *prev = NULL, *tmp;
>
>   pbc = reg->pbc_sessions;
>   while (pbc) {
> - if (os_memcmp(pbc->uuid_e, uuid_e, WPS_UUID_LEN) == 0) {
> + if (os_memcmp(pbc->uuid_e, uuid_e, WPS_UUID_LEN) == 0 ||
> +    (!is_zero_ether_addr(reg->p2p_dev_addr) &&
> +     !os_memcmp(reg->p2p_dev_addr, p2p_dev_addr, ETH_ALEN))) {
>   if (prev)
>   prev->next = pbc->next;
>   else
> @@ -3035,7 +3038,8 @@ static enum wps_process_res
> wps_process_wsc_done(struct wps_data *wps,
>
>   if (wps->pbc) {
>   wps_registrar_remove_pbc_session(wps->wps->registrar,
> - wps->uuid_e);
> + wps->uuid_e,
> + wps->p2p_dev_addr);
>   wps_registrar_pbc_completed(wps->wps->registrar);
>   } else {
>   wps_registrar_pin_completed(wps->wps->registrar);
> diff --git a/wpa_supplicant/p2p_supplicant.c
> b/wpa_supplicant/p2p_supplicant.c
> index c6484af..1700ace 100644
> --- a/wpa_supplicant/p2p_supplicant.c
> +++ b/wpa_supplicant/p2p_supplicant.c
> @@ -689,7 +689,7 @@ static void p2p_go_configured(void *ctx, void *data)
>   }
>   if (params->wps_method == WPS_PBC)
>   wpa_supplicant_ap_wps_pbc(wpa_s, params->peer_interface_addr,
> -  NULL);
> +  params->peer_device_addr);
>   else if (wpa_s->p2p_pin[0])
>   wpa_supplicant_ap_wps_pin(wpa_s, params->peer_interface_addr,
>    wpa_s->p2p_pin, NULL, 0);
>
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