P2P: Do not change SSID during GO negotiation

If GO Negotiation Request (or in theory, also GO Negotiation Response)
frame is delivered multiple time for processing, the SSID of the group
could end up getting changed. This could result in possible issues if
the peer ended up using different SSID. To avoid this, make sure the
SSID does not get changed unless the negotiation is for a new group.

src/p2p/p2p.c

@@ -1047,6 +1047,7 @@ int p2p_connect(struct p2p_data *p2p, const u8 *peer_addr,
 	if (p2p_prepare_channel(p2p, force_freq) < 0)
 		return -1;
 
+	p2p->ssid_set = 0;
 	dev = p2p_get_device(p2p, peer_addr);
 	if (dev == NULL || (dev->flags & P2P_DEV_PROBE_REQ_ONLY)) {
 		wpa_msg(p2p->cfg->msg_ctx, MSG_DEBUG,
@@ -1314,6 +1315,7 @@ void p2p_go_complete(struct p2p_data *p2p, struct p2p_device *peer)
 	res.peer_config_timeout = go ? peer->client_timeout : peer->go_timeout;
 
 	p2p_clear_timeout(p2p);
+	p2p->ssid_set = 0;
 	peer->go_neg_req_sent = 0;
 	peer->wps_method = WPS_NOT_READY;
 

src/p2p/p2p_go_neg.c

@@ -581,7 +581,10 @@ void p2p_process_go_neg_req(struct p2p_data *p2p, const u8 *sa,
 						   p2p->op_channel))
 				p2p_reselect_channel(p2p, &intersection);
 
-			p2p_build_ssid(p2p, p2p->ssid, &p2p->ssid_len);
+			if (!p2p->ssid_set) {
+				p2p_build_ssid(p2p, p2p->ssid, &p2p->ssid_len);
+				p2p->ssid_set = 1;
+			}
 		}
 
 		dev->go_state = go ? LOCAL_GO : REMOTE_GO;
@@ -950,7 +953,10 @@ void p2p_process_go_neg_resp(struct p2p_data *p2p, const u8 *sa,
 					   p2p->op_channel))
 			p2p_reselect_channel(p2p, &intersection);
 
-		p2p_build_ssid(p2p, p2p->ssid, &p2p->ssid_len);
+		if (!p2p->ssid_set) {
+			p2p_build_ssid(p2p, p2p->ssid, &p2p->ssid_len);
+			p2p->ssid_set = 1;
+		}
 	}
 
 	p2p_set_state(p2p, P2P_GO_NEG);

src/p2p/p2p_i.h

@@ -272,6 +272,11 @@ struct p2p_data {
 	 */
 	size_t ssid_len;
 
+	/**
+	 * ssid_set - Whether SSID is already set for GO Negotiation
+	 */
+	int ssid_set;
+
 	/**
 	 * Regulatory class for own operational channel
 	 */