P2PS: Fix persistent group reporting in wpas_p2ps_prov_complete()

When one peer doesn't include a persistent group info in PD Request
the other peer shouldn't report a persistent group usage with this
peer even if such a persistent group exists locally. This condition
could be violated in the previous implementation.

In case a local persistent group exists and the
wpas_p2ps_prov_complete() function is called with persist_ssid parameter
set to NULL, wpa_supplicant reported P2PS-PROV-DONE with persist=<idx>
instead of conncap=<role> parameter.

This happened because the wpas_p2p_get_persistent() function was called
without verification whether the persist_ssid was set to NULL. In this
case the wpas_p2p_get_persistent() returns the first existing persistent
group matching the P2P Device Address without verifying the group's
SSID. After that the group ID is used as persist=<idx> parameter of
P2PS-PROV-DONE event.

Fix the issue by adding persist_ssid and persist_ssid_size verification
as a condition for the wpas_p2p_get_persistent() call.

Signed-off-by: Max Stepanov <Max.Stepanov@intel.com>

wpa_supplicant/p2p_supplicant.c

@@ -3817,7 +3817,7 @@ static void wpas_p2ps_prov_complete(void *ctx, u8 status, const u8 *dev,
 {
 	struct wpa_supplicant *wpa_s = ctx;
 	u8 mac[ETH_ALEN];
-	struct wpa_ssid *persistent_go, *stale, *s;
+	struct wpa_ssid *persistent_go, *stale, *s = NULL;
 	int save_config = 0;
 	struct wpa_supplicant *go_wpa_s;
 	char feat_cap_str[256];
@@ -3888,8 +3888,9 @@ static void wpas_p2ps_prov_complete(void *ctx, u8 status, const u8 *dev,
 	}
 
 	/* Clean up stale persistent groups with this device */
-	s = wpas_p2p_get_persistent(wpa_s, dev, persist_ssid,
-				    persist_ssid_size);
+	if (persist_ssid && persist_ssid_size)
+		s = wpas_p2p_get_persistent(wpa_s, dev, persist_ssid,
+					    persist_ssid_size);
 
 	if (persist_ssid && s && s->mode != WPAS_MODE_P2P_GO &&
 	    is_zero_ether_addr(grp_mac)) {