FILS: Find PMKSA cache entries on AP based on FILS Cache Identifier

This allows PMKSA cache entries to be shared between all the BSSs
operated by the same hostapd process when those BSSs use the same FILS
Cache Identifier value.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/ap/ieee802_11.c

@@ -1099,6 +1099,11 @@ static void handle_auth_fils(struct hostapd_data *hapd, struct sta_info *sta,
 						   pmkid);
 			if (pmksa)
 				break;
+			pmksa = wpa_auth_pmksa_get_fils_cache_id(hapd->wpa_auth,
+								 sta->addr,
+								 pmkid);
+			if (pmksa)
+				break;
 			pmkid += PMKID_LEN;
 			num--;
 		}

src/ap/wpa_auth.c

@@ -4216,3 +4216,47 @@ void wpa_auth_reconfig_group_keys(struct wpa_authenticator *wpa_auth)
 	for (group = wpa_auth->group; group; group = group->next)
 		wpa_group_config_group_keys(wpa_auth, group);
 }
+
+
+#ifdef CONFIG_FILS
+
+struct wpa_auth_fils_iter_data {
+	struct wpa_authenticator *auth;
+	const u8 *cache_id;
+	struct rsn_pmksa_cache_entry *pmksa;
+	const u8 *spa;
+	const u8 *pmkid;
+};
+
+
+static int wpa_auth_fils_iter(struct wpa_authenticator *a, void *ctx)
+{
+	struct wpa_auth_fils_iter_data *data = ctx;
+
+	if (a == data->auth || !a->conf.fils_cache_id ||
+	    os_memcmp(a->conf.fils_cache_id, data->cache_id,
+		      FILS_CACHE_ID_LEN) != 0)
+		return 0;
+	data->pmksa = pmksa_cache_auth_get(a->pmksa, data->spa, data->pmkid);
+	return data->pmksa != NULL;
+}
+
+
+struct rsn_pmksa_cache_entry *
+wpa_auth_pmksa_get_fils_cache_id(struct wpa_authenticator *wpa_auth,
+				 const u8 *sta_addr, const u8 *pmkid)
+{
+	struct wpa_auth_fils_iter_data idata;
+
+	if (!wpa_auth->conf.fils_cache_id_set)
+		return NULL;
+	idata.auth = wpa_auth;
+	idata.cache_id = wpa_auth->conf.fils_cache_id;
+	idata.pmksa = NULL;
+	idata.spa = sta_addr;
+	idata.pmkid = pmkid;
+	wpa_auth_for_each_auth(wpa_auth, wpa_auth_fils_iter, &idata);
+	return idata.pmksa;
+}
+
+#endif /* CONFIG_FILS */

src/ap/wpa_auth.h

@@ -187,6 +187,10 @@ struct wpa_auth_config {
 	u8 ip_addr_start[4];
 	u8 ip_addr_end[4];
 #endif /* CONFIG_P2P */
+#ifdef CONFIG_FILS
+	unsigned int fils_cache_id_set:1;
+	u8 fils_cache_id[FILS_CACHE_ID_LEN];
+#endif /* CONFIG_FILS */
 };
 
 typedef enum {
@@ -314,6 +318,9 @@ int wpa_auth_pmksa_add_entry(struct wpa_authenticator *wpa_auth,
 struct rsn_pmksa_cache_entry *
 wpa_auth_pmksa_get(struct wpa_authenticator *wpa_auth, const u8 *sta_addr,
 		   const u8 *pmkid);
+struct rsn_pmksa_cache_entry *
+wpa_auth_pmksa_get_fils_cache_id(struct wpa_authenticator *wpa_auth,
+				 const u8 *sta_addr, const u8 *pmkid);
 void wpa_auth_pmksa_set_to_sm(struct rsn_pmksa_cache_entry *pmksa,
 			      struct wpa_state_machine *sm,
 			      struct wpa_authenticator *wpa_auth,

src/ap/wpa_auth_glue.c

@@ -110,6 +110,11 @@ static void hostapd_wpa_auth_conf(struct hostapd_bss_config *conf,
 	os_memcpy(wconf->ip_addr_start, conf->ip_addr_start, 4);
 	os_memcpy(wconf->ip_addr_end, conf->ip_addr_end, 4);
 #endif /* CONFIG_P2P */
+#ifdef CONFIG_FILS
+	wconf->fils_cache_id_set = conf->fils_cache_id_set;
+	os_memcpy(wconf->fils_cache_id, conf->fils_cache_id,
+		  FILS_CACHE_ID_LEN);
+#endif /* CONFIG_FILS */
 }