mesh: Fix SAE anti-clogging functionality for mesh

The mesh anti-clogging functionality is implemented partially. This
patch fixes to parse anti-clogging request frame and use anti-clogging
token.

Signed-off-by: Masashi Honma <masashi.honma@gmail.com>

diff --git a/src/ap/ieee802_11.c b/src/ap/ieee802_11.c
index cca3984..1d0fa51 100644 (file)
--- a/src/ap/ieee802_11.c
+++ b/src/ap/ieee802_11.c
@@ -326,7 +326,7 @@ static void handle_auth_ft_finish(void *ctx, const u8 *dst, const u8 *bssid,
 #ifdef CONFIG_SAE
 
 static struct wpabuf * auth_build_sae_commit(struct hostapd_data *hapd,
-                                            struct sta_info *sta)
+                                            struct sta_info *sta, int update)
 {
        struct wpabuf *buf;
 
@@ -335,7 +335,8 @@ static struct wpabuf * auth_build_sae_commit(struct hostapd_data *hapd,
                return NULL;
        }
 
-       if (sae_prepare_commit(hapd->own_addr, sta->addr,
+       if (update &&
+           sae_prepare_commit(hapd->own_addr, sta->addr,
                               (u8 *) hapd->conf->ssid.wpa_passphrase,
                               os_strlen(hapd->conf->ssid.wpa_passphrase),
                               sta->sae) < 0) {
@@ -346,7 +347,8 @@ static struct wpabuf * auth_build_sae_commit(struct hostapd_data *hapd,
        buf = wpabuf_alloc(SAE_COMMIT_MAX_LEN);
        if (buf == NULL)
                return NULL;
-       sae_write_commit(sta->sae, buf, NULL);
+       sae_write_commit(sta->sae, buf, sta->sae->tmp ?
+                        sta->sae->tmp->anti_clogging_token : NULL);
 
        return buf;
 }
@@ -369,11 +371,11 @@ static struct wpabuf * auth_build_sae_confirm(struct hostapd_data *hapd,
 
 static int auth_sae_send_commit(struct hostapd_data *hapd,
                                struct sta_info *sta,
-                               const u8 *bssid)
+                               const u8 *bssid, int update)
 {
        struct wpabuf *data;
 
-       data = auth_build_sae_commit(hapd, sta);
+       data = auth_build_sae_commit(hapd, sta, update);
        if (data == NULL)
                return WLAN_STATUS_UNSPECIFIED_FAILURE;
 
@@ -487,7 +489,7 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
        switch (sta->sae->state) {
        case SAE_NOTHING:
                if (auth_transaction == 1) {
-                       ret = auth_sae_send_commit(hapd, sta, bssid);
+                       ret = auth_sae_send_commit(hapd, sta, bssid, 1);
                        if (ret)
                                return ret;
                        sta->sae->state = SAE_COMMITTED;
@@ -544,7 +546,7 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
                         * In mesh case, follow SAE finite state machine and
                         * send Commit now.
                         */
-                       ret = auth_sae_send_commit(hapd, sta, bssid);
+                       ret = auth_sae_send_commit(hapd, sta, bssid, 1);
                        if (ret)
                                return ret;
                } else {
@@ -569,7 +571,7 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
                break;
        case SAE_CONFIRMED:
                if (auth_transaction == 1) {
-                       ret = auth_sae_send_commit(hapd, sta, bssid);
+                       ret = auth_sae_send_commit(hapd, sta, bssid, 1);
                        if (ret)
                                return ret;
 
@@ -633,6 +635,37 @@ static void handle_auth_sae(struct hostapd_data *hapd, struct sta_info *sta,
                hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211,
                               HOSTAPD_LEVEL_DEBUG,
                               "start SAE authentication (RX commit)");
+
+               if ((hapd->conf->mesh & MESH_ENABLED) &&
+                   mgmt->u.auth.status_code ==
+                   WLAN_STATUS_ANTI_CLOGGING_TOKEN_REQ && sta->sae->tmp) {
+                       wpabuf_free(sta->sae->tmp->anti_clogging_token);
+                       sta->sae->tmp->anti_clogging_token =
+                               wpabuf_alloc_copy(mgmt->u.auth.variable,
+                                                 ((const u8 *) mgmt) + len -
+                                                 mgmt->u.auth.variable);
+                       if (sta->sae->tmp->anti_clogging_token == NULL) {
+                               wpa_printf(MSG_ERROR,
+                                          "SAE: Failed to alloc for anti-clogging token");
+                               return;
+                       }
+
+                       /*
+                        * IEEE Std 802.11-2012, 11.3.8.6.4: If the Status code
+                        * is 76, a new Commit Message shall be constructed
+                        * with the Anti-Clogging Token from the received
+                        * Authentication frame, and the commit-scalar and
+                        * COMMIT-ELEMENT previously sent.
+                        */
+                       if (auth_sae_send_commit(hapd, sta, mgmt->bssid, 0)) {
+                               wpa_printf(MSG_ERROR,
+                                          "SAE: Failed to send commit message");
+                               return;
+                       }
+                       sta->sae->state = SAE_COMMITTED;
+                       return;
+               }
+
                resp = sae_parse_commit(sta->sae, mgmt->u.auth.variable,
                                        ((const u8 *) mgmt) + len -
                                        mgmt->u.auth.variable, &token,
@@ -654,6 +687,8 @@ static void handle_auth_sae(struct hostapd_data *hapd, struct sta_info *sta,
                                   MACSTR, MAC2STR(sta->addr));
                        data = auth_build_token_req(hapd, sta->addr);
                        resp = WLAN_STATUS_ANTI_CLOGGING_TOKEN_REQ;
+                       if (hapd->conf->mesh & MESH_ENABLED)
+                               sta->sae->state = SAE_NOTHING;
                        goto reply;
                }
 

diff --git a/src/common/sae.c b/src/common/sae.c
index b67623f..6454b4a 100644 (file)
--- a/src/common/sae.c
+++ b/src/common/sae.c
@@ -87,6 +87,7 @@ void sae_clear_temp_data(struct sae_data *sae)
        crypto_ec_point_deinit(tmp->pwe_ecc, 1);
        crypto_ec_point_deinit(tmp->own_commit_element_ecc, 0);
        crypto_ec_point_deinit(tmp->peer_commit_element_ecc, 0);
+       wpabuf_free(tmp->anti_clogging_token);
        os_free(sae->tmp);
        sae->tmp = NULL;
 }
@@ -656,8 +657,11 @@ void sae_write_commit(struct sae_data *sae, struct wpabuf *buf,
                return;
 
        wpabuf_put_le16(buf, sae->group); /* Finite Cyclic Group */
-       if (token)
+       if (token) {
                wpabuf_put_buf(buf, token);
+               wpa_hexdump(MSG_DEBUG, "SAE: Anti-clogging token",
+                           wpabuf_head(token), wpabuf_len(token));
+       }
        pos = wpabuf_put(buf, sae->tmp->prime_len);
        crypto_bignum_to_bin(sae->tmp->own_commit_scalar, pos,
                             sae->tmp->prime_len, sae->tmp->prime_len);

diff --git a/src/common/sae.h b/src/common/sae.h
index d82a98e..e78bb49 100644 (file)
--- a/src/common/sae.h
+++ b/src/common/sae.h
@@ -35,6 +35,7 @@ struct sae_temporary_data {
        const struct crypto_bignum *order;
        struct crypto_bignum *prime_buf;
        struct crypto_bignum *order_buf;
+       struct wpabuf *anti_clogging_token;
 };
 
 struct sae_data {