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-rw-r--r--wpa_supplicant/mesh_rsn.c573
1 files changed, 573 insertions, 0 deletions
diff --git a/wpa_supplicant/mesh_rsn.c b/wpa_supplicant/mesh_rsn.c
new file mode 100644
index 0000000..ecc6393
--- /dev/null
+++ b/wpa_supplicant/mesh_rsn.c
@@ -0,0 +1,573 @@
+/*
+ * WPA Supplicant - Mesh RSN routines
+ * Copyright (c) 2013-2014, cozybit, Inc. All rights reserved.
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "utils/includes.h"
+
+#include "utils/common.h"
+#include "crypto/sha256.h"
+#include "crypto/random.h"
+#include "crypto/aes.h"
+#include "crypto/aes_siv.h"
+#include "rsn_supp/wpa.h"
+#include "ap/hostapd.h"
+#include "ap/wpa_auth.h"
+#include "ap/sta_info.h"
+#include "wpa_supplicant_i.h"
+#include "driver_i.h"
+#include "wpas_glue.h"
+#include "mesh_mpm.h"
+#include "mesh_rsn.h"
+
+
+static void auth_logger(void *ctx, const u8 *addr, logger_level level,
+ const char *txt)
+{
+ if (addr)
+ wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
+ MAC2STR(addr), txt);
+ else
+ wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
+}
+
+
+static const u8 *auth_get_psk(void *ctx, const u8 *addr,
+ const u8 *p2p_dev_addr, const u8 *prev_psk)
+{
+ struct mesh_rsn *mesh_rsn = ctx;
+ struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
+ struct sta_info *sta = ap_get_sta(hapd, addr);
+
+ wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
+ __func__, MAC2STR(addr), prev_psk);
+
+ if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
+ if (!sta->sae || prev_psk)
+ return NULL;
+ return sta->sae->pmk;
+ }
+
+ return NULL;
+}
+
+
+static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
+ const u8 *addr, int idx, u8 *key, size_t key_len)
+{
+ struct mesh_rsn *mesh_rsn = ctx;
+ u8 seq[6];
+
+ os_memset(seq, 0, sizeof(seq));
+
+ if (addr) {
+ wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
+ " key_idx=%d)",
+ __func__, alg, MAC2STR(addr), idx);
+ } else {
+ wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
+ __func__, alg, idx);
+ }
+ wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
+
+ return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
+ 1, seq, 6, key, key_len);
+}
+
+
+static int auth_start_ampe(void *ctx, const u8 *addr)
+{
+ struct mesh_rsn *mesh_rsn = ctx;
+
+ if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
+ return -1;
+
+ mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
+ return 0;
+}
+
+
+static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr)
+{
+ struct wpa_auth_config conf;
+ struct wpa_auth_callbacks cb;
+ u8 seq[6] = {};
+
+ wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
+
+ os_memset(&conf, 0, sizeof(conf));
+ conf.wpa = 2;
+ conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
+ conf.wpa_pairwise = WPA_CIPHER_CCMP;
+ conf.rsn_pairwise = WPA_CIPHER_CCMP;
+ conf.wpa_group = WPA_CIPHER_CCMP;
+ conf.eapol_version = 0;
+ conf.wpa_group_rekey = -1;
+
+ os_memset(&cb, 0, sizeof(cb));
+ cb.ctx = rsn;
+ cb.logger = auth_logger;
+ cb.get_psk = auth_get_psk;
+ cb.set_key = auth_set_key;
+ cb.start_ampe = auth_start_ampe;
+
+ rsn->auth = wpa_init(addr, &conf, &cb);
+ if (rsn->auth == NULL) {
+ wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
+ return -1;
+ }
+
+ /* TODO: support rekeying */
+ if (random_get_bytes(rsn->mgtk, 16) < 0) {
+ wpa_deinit(rsn->auth);
+ return -1;
+ }
+
+ /* group mgmt */
+ wpa_drv_set_key(rsn->wpa_s, WPA_ALG_IGTK, NULL, 4, 1,
+ seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
+
+ /* group privacy / data frames */
+ wpa_drv_set_key(rsn->wpa_s, WPA_ALG_CCMP, NULL, 1, 1,
+ seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
+
+ return 0;
+}
+
+
+static void mesh_rsn_deinit(struct mesh_rsn *rsn)
+{
+ os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
+ wpa_deinit(rsn->auth);
+}
+
+
+struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
+ struct mesh_conf *conf)
+{
+ struct mesh_rsn *mesh_rsn;
+ struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
+ const u8 *ie;
+ size_t ie_len;
+
+ mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
+ if (mesh_rsn == NULL)
+ return NULL;
+ mesh_rsn->wpa_s = wpa_s;
+
+ if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr) < 0) {
+ mesh_rsn_deinit(mesh_rsn);
+ return NULL;
+ }
+
+ bss->wpa_auth = mesh_rsn->auth;
+
+ ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
+ conf->ies = (u8 *) ie;
+ conf->ie_len = ie_len;
+
+ wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
+
+ return mesh_rsn;
+}
+
+
+static int index_within_array(const int *array, int idx)
+{
+ int i;
+
+ for (i = 0; i < idx; i++) {
+ if (array[i] == -1)
+ return 0;
+ }
+
+ return 1;
+}
+
+
+static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
+ struct sae_data *sae)
+{
+ int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
+
+ /* Configuration may have changed, so validate current index */
+ if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
+ return -1;
+
+ for (;;) {
+ int group = groups[wpa_s->mesh_rsn->sae_group_index];
+
+ if (group <= 0)
+ break;
+ if (sae_set_group(sae, group) == 0) {
+ wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
+ sae->group);
+ return 0;
+ }
+ wpa_s->mesh_rsn->sae_group_index++;
+ }
+
+ return -1;
+}
+
+
+struct wpabuf *
+mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
+ struct wpa_ssid *ssid, struct sta_info *sta)
+{
+ struct wpabuf *buf;
+ int len;
+
+ if (ssid->passphrase == NULL) {
+ wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
+ return NULL;
+ }
+
+ if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
+ wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
+ return NULL;
+ }
+
+ if (sae_prepare_commit(wpa_s->own_addr, sta->addr,
+ (u8 *) ssid->passphrase,
+ os_strlen(ssid->passphrase), sta->sae) < 0) {
+ wpa_msg(wpa_s, MSG_DEBUG, "SAE: Could not pick PWE");
+ return NULL;
+ }
+
+ len = wpa_s->mesh_rsn->sae_token ?
+ wpabuf_len(wpa_s->mesh_rsn->sae_token) : 0;
+ buf = wpabuf_alloc(4 + SAE_COMMIT_MAX_LEN + len);
+ if (buf == NULL)
+ return NULL;
+
+ sae_write_commit(sta->sae, buf, wpa_s->mesh_rsn->sae_token);
+
+ return buf;
+}
+
+
+static void mesh_rsn_send_auth(struct wpa_supplicant *wpa_s,
+ const u8 *dst, const u8 *src,
+ u16 auth_transaction, u16 resp,
+ struct wpabuf *data)
+{
+ struct ieee80211_mgmt *auth;
+ u8 *buf;
+ size_t len, ielen = 0;
+
+ if (data)
+ ielen = wpabuf_len(data);
+ len = IEEE80211_HDRLEN + sizeof(auth->u.auth) + ielen;
+ buf = os_zalloc(len);
+ if (buf == NULL)
+ return;
+
+ auth = (struct ieee80211_mgmt *) buf;
+ auth->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
+ WLAN_FC_STYPE_AUTH);
+ os_memcpy(auth->da, dst, ETH_ALEN);
+ os_memcpy(auth->sa, src, ETH_ALEN);
+ os_memcpy(auth->bssid, src, ETH_ALEN);
+
+ auth->u.auth.auth_alg = host_to_le16(WLAN_AUTH_SAE);
+ auth->u.auth.auth_transaction = host_to_le16(auth_transaction);
+ auth->u.auth.status_code = host_to_le16(resp);
+
+ if (data)
+ os_memcpy(auth->u.auth.variable, wpabuf_head(data), ielen);
+
+ wpa_msg(wpa_s, MSG_DEBUG, "authentication frame: STA=" MACSTR
+ " auth_transaction=%d resp=%d (IE len=%lu)",
+ MAC2STR(dst), auth_transaction, resp, (unsigned long) ielen);
+ if (wpa_drv_send_mlme(wpa_s, buf, len, 0) < 0)
+ perror("send_auth_reply: send");
+
+ os_free(buf);
+}
+
+
+/* initiate new SAE authentication with sta */
+int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
+ struct sta_info *sta)
+{
+ struct wpa_ssid *ssid = wpa_s->current_ssid;
+ struct wpabuf *buf;
+
+ if (!sta->sae) {
+ sta->sae = os_zalloc(sizeof(*sta->sae));
+ if (sta->sae == NULL)
+ return -1;
+ }
+
+ buf = mesh_rsn_build_sae_commit(wpa_s, ssid, sta);
+ if (!buf)
+ return -1;
+
+ wpa_msg(wpa_s, MSG_DEBUG,
+ "AUTH: started authentication with SAE peer: " MACSTR,
+ MAC2STR(sta->addr));
+
+ sta->sae->state = SAE_COMMITTED;
+ wpa_supplicant_set_state(wpa_s, WPA_AUTHENTICATING);
+
+ mesh_rsn_send_auth(wpa_s, sta->addr, wpa_s->own_addr,
+ 1, WLAN_STATUS_SUCCESS, buf);
+
+ wpabuf_free(buf);
+
+ return 0;
+}
+
+
+void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
+{
+ /* don't expect wpa auth to cache the pmkid for now */
+ rsn_pmkid(sta->sae->pmk, PMK_LEN, rsn->wpa_s->own_addr,
+ sta->addr, pmkid,
+ wpa_key_mgmt_sha256(wpa_auth_sta_key_mgmt(sta->wpa_sm)));
+}
+
+
+static void
+mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
+{
+ u8 *myaddr = rsn->wpa_s->own_addr;
+ u8 *peer = sta->addr;
+ u8 *addr1 = peer, *addr2 = myaddr;
+ u8 context[AES_BLOCK_SIZE];
+
+ /* SAE */
+ RSN_SELECTOR_PUT(context, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
+
+ if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
+ addr1 = myaddr;
+ addr2 = peer;
+ }
+ os_memcpy(context + 4, addr1, ETH_ALEN);
+ os_memcpy(context + 10, addr2, ETH_ALEN);
+
+ sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
+ context, sizeof(context), sta->aek, sizeof(sta->aek));
+}
+
+
+/* derive mesh temporal key from pmk */
+int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
+{
+ u8 *ptr;
+ u8 *min, *max;
+ u16 min_lid, max_lid;
+ size_t nonce_len = sizeof(sta->my_nonce);
+ size_t lid_len = sizeof(sta->my_lid);
+ u8 *myaddr = wpa_s->own_addr;
+ u8 *peer = sta->addr;
+ /* 2 nonces, 2 linkids, akm suite, 2 mac addrs */
+ u8 context[64 + 4 + 4 + 12];
+
+ ptr = context;
+ if (os_memcmp(sta->my_nonce, sta->peer_nonce, nonce_len) < 0) {
+ min = sta->my_nonce;
+ max = sta->peer_nonce;
+ } else {
+ min = sta->peer_nonce;
+ max = sta->my_nonce;
+ }
+ os_memcpy(ptr, min, nonce_len);
+ os_memcpy(ptr + nonce_len, max, nonce_len);
+ ptr += 2 * nonce_len;
+
+ if (sta->my_lid < sta->peer_lid) {
+ min_lid = host_to_le16(sta->my_lid);
+ max_lid = host_to_le16(sta->peer_lid);
+ } else {
+ min_lid = host_to_le16(sta->peer_lid);
+ max_lid = host_to_le16(sta->my_lid);
+ }
+ os_memcpy(ptr, &min_lid, lid_len);
+ os_memcpy(ptr + lid_len, &max_lid, lid_len);
+ ptr += 2 * lid_len;
+
+ /* SAE */
+ RSN_SELECTOR_PUT(ptr, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
+ ptr += 4;
+
+ if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
+ min = myaddr;
+ max = peer;
+ } else {
+ min = peer;
+ max = myaddr;
+ }
+ os_memcpy(ptr, min, ETH_ALEN);
+ os_memcpy(ptr + ETH_ALEN, max, ETH_ALEN);
+
+ sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk),
+ "Temporal Key Derivation", context, sizeof(context),
+ sta->mtk, sizeof(sta->mtk));
+ return 0;
+}
+
+
+void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
+{
+ if (random_get_bytes(sta->my_nonce, 32) < 0) {
+ wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
+ /* TODO: How to handle this more cleanly? */
+ }
+ os_memset(sta->peer_nonce, 0, 32);
+ mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
+}
+
+
+/* insert AMPE and encrypted MIC at @ie.
+ * @mesh_rsn: mesh RSN context
+ * @sta: STA we're sending to
+ * @cat: pointer to category code in frame header.
+ * @buf: wpabuf to add encrypted AMPE and MIC to.
+ * */
+int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
+ const u8 *cat, struct wpabuf *buf)
+{
+ struct ieee80211_ampe_ie *ampe;
+ u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
+ u8 *ampe_ie = NULL, *mic_ie = NULL, *mic_payload;
+ const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
+ const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
+ int ret = 0;
+
+ if (AES_BLOCK_SIZE + 2 + sizeof(*ampe) + 2 > wpabuf_tailroom(buf)) {
+ wpa_printf(MSG_ERROR, "protect frame: buffer too small");
+ return -EINVAL;
+ }
+
+ ampe_ie = os_zalloc(2 + sizeof(*ampe));
+ if (!ampe_ie) {
+ wpa_printf(MSG_ERROR, "protect frame: out of memory");
+ return -ENOMEM;
+ }
+
+ mic_ie = os_zalloc(2 + AES_BLOCK_SIZE);
+ if (!mic_ie) {
+ wpa_printf(MSG_ERROR, "protect frame: out of memory");
+ ret = -ENOMEM;
+ goto free;
+ }
+
+ /* IE: AMPE */
+ ampe_ie[0] = WLAN_EID_AMPE;
+ ampe_ie[1] = sizeof(*ampe);
+ ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
+
+ RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
+ wpa_cipher_to_suite(WPA_PROTO_RSN, WPA_CIPHER_CCMP));
+ os_memcpy(ampe->local_nonce, sta->my_nonce, 32);
+ os_memcpy(ampe->peer_nonce, sta->peer_nonce, 32);
+ /* incomplete: see 13.5.4 */
+ /* TODO: static mgtk for now since we don't support rekeying! */
+ os_memcpy(ampe->mgtk, rsn->mgtk, 16);
+ /* TODO: Populate Key RSC */
+ /* expire in 13 decades or so */
+ os_memset(ampe->key_expiration, 0xff, 4);
+
+ /* IE: MIC */
+ mic_ie[0] = WLAN_EID_MIC;
+ mic_ie[1] = AES_BLOCK_SIZE;
+ wpabuf_put_data(buf, mic_ie, 2);
+ /* MIC field is output ciphertext */
+
+ /* encrypt after MIC */
+ mic_payload = (u8 *) wpabuf_put(buf, 2 + sizeof(*ampe) +
+ AES_BLOCK_SIZE);
+
+ if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + sizeof(*ampe), 3,
+ aad, aad_len, mic_payload)) {
+ wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
+ ret = -ENOMEM;
+ goto free;
+ }
+
+free:
+ os_free(ampe_ie);
+ os_free(mic_ie);
+
+ return ret;
+}
+
+
+int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
+ struct ieee802_11_elems *elems, const u8 *cat,
+ const u8 *start, size_t elems_len)
+{
+ int ret = 0;
+ struct ieee80211_ampe_ie *ampe;
+ u8 null_nonce[32] = {};
+ u8 ampe_eid;
+ u8 ampe_ie_len;
+ u8 *ampe_buf, *crypt = NULL;
+ size_t crypt_len;
+ const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
+ const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
+ (elems->mic - 2) - cat };
+
+ if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
+ wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
+ return -1;
+ }
+
+ ampe_buf = (u8 *) elems->mic + elems->mic_len;
+ if ((int) elems_len < ampe_buf - start)
+ return -1;
+
+ crypt_len = elems_len - (elems->mic - start);
+ if (crypt_len < 2) {
+ wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
+ return -1;
+ }
+
+ /* crypt is modified by siv_decrypt */
+ crypt = os_zalloc(crypt_len);
+ if (!crypt) {
+ wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
+ ret = -ENOMEM;
+ goto free;
+ }
+
+ os_memcpy(crypt, elems->mic, crypt_len);
+
+ if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3,
+ aad, aad_len, ampe_buf)) {
+ wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
+ ret = -1;
+ goto free;
+ }
+
+ ampe_eid = *ampe_buf++;
+ ampe_ie_len = *ampe_buf++;
+
+ if (ampe_eid != WLAN_EID_AMPE ||
+ ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
+ wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
+ ret = -1;
+ goto free;
+ }
+
+ ampe = (struct ieee80211_ampe_ie *) ampe_buf;
+ if (os_memcmp(ampe->peer_nonce, null_nonce, 32) != 0 &&
+ os_memcmp(ampe->peer_nonce, sta->my_nonce, 32) != 0) {
+ wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
+ ret = -1;
+ goto free;
+ }
+ os_memcpy(sta->peer_nonce, ampe->local_nonce,
+ sizeof(ampe->local_nonce));
+ os_memcpy(sta->mgtk, ampe->mgtk, sizeof(ampe->mgtk));
+
+ /* todo parse mgtk expiration */
+free:
+ os_free(crypt);
+ return ret;
+}