wpa_supplicant/mesh_rsn.c - LeafOS-Project/android_external_wpa_supplicant_8 - Gitiles

 /*
  * 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 "utils/eloop.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 "ap/ieee802_11.h"
 #include "wpa_supplicant_i.h"
 #include "driver_i.h"
 #include "wpas_glue.h"
 #include "mesh_mpm.h"
 #include "mesh_rsn.h"

 #define MESH_AUTH_TIMEOUT 10
 #define MESH_AUTH_RETRY 3

 void mesh_auth_timer(void *eloop_ctx, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = eloop_ctx;
 	struct sta_info *sta = user_data;
 	struct hostapd_data *hapd;

 	if (sta->sae->state != SAE_ACCEPTED) {
 		wpa_printf(MSG_DEBUG, "AUTH: Re-authenticate with " MACSTR
 			   " (attempt %d) ",
 			   MAC2STR(sta->addr), sta->sae_auth_retry);
 		wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_FAILURE "addr=" MACSTR,
 			MAC2STR(sta->addr));
 		if (sta->sae_auth_retry < MESH_AUTH_RETRY) {
 			mesh_rsn_auth_sae_sta(wpa_s, sta);
 		} else {
 			hapd = wpa_s->ifmsh->bss[0];

 			if (sta->sae_auth_retry > MESH_AUTH_RETRY) {
 				ap_free_sta(hapd, sta);
 				return;
 			}

 			/* block the STA if exceeded the number of attempts */
 			wpa_mesh_set_plink_state(wpa_s, sta, PLINK_BLOCKED);
 			sta->sae->state = SAE_NOTHING;
 			wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_BLOCKED "addr="
 				MACSTR " duration=%d",
 				MAC2STR(sta->addr),
 				hapd->conf->ap_max_inactivity);
 		}
 		sta->sae_auth_retry++;
 	}
 }


 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,
 			      size_t *psk_len, int *vlan_id)
 {
 	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);

 	if (psk_len)
 		*psk_len = PMK_LEN;
 	if (vlan_id)
 		*vlan_id = 0;
 	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,
 			enum key_flag key_flag)
 {
 	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, key_flag);
 }


 static int auth_start_ampe(void *ctx, const u8 *addr)
 {
 	struct mesh_rsn *mesh_rsn = ctx;
 	struct hostapd_data *hapd;
 	struct sta_info *sta;

 	if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
 		return -1;

 	hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
 	sta = ap_get_sta(hapd, addr);
 	if (sta)
 		eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);

 	mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
 	return 0;
 }


 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
 				enum mfp_options ieee80211w, int ocv)
 {
 	struct wpa_auth_config conf;
 	static const struct wpa_auth_callbacks cb = {
 		.logger = auth_logger,
 		.get_psk = auth_get_psk,
 		.set_key = auth_set_key,
 		.start_ampe = auth_start_ampe,
 	};
 	u8 seq[6] = {};

 	wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");

 	os_memset(&conf, 0, sizeof(conf));
 	conf.wpa = WPA_PROTO_RSN;
 	conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
 	conf.wpa_pairwise = rsn->pairwise_cipher;
 	conf.rsn_pairwise = rsn->pairwise_cipher;
 	conf.wpa_group = rsn->group_cipher;
 	conf.eapol_version = 0;
 	conf.wpa_group_rekey = -1;
 	conf.wpa_group_update_count = 4;
 	conf.wpa_pairwise_update_count = 4;
 	conf.ieee80211w = ieee80211w;
 	if (ieee80211w != NO_MGMT_FRAME_PROTECTION)
 		conf.group_mgmt_cipher = rsn->mgmt_group_cipher;
 #ifdef CONFIG_OCV
 	conf.ocv = ocv;
 #endif /* CONFIG_OCV */

 	rsn->auth = wpa_init(addr, &conf, &cb, rsn);
 	if (rsn->auth == NULL) {
 		wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
 		return -1;
 	}

 	/* TODO: support rekeying */
 	rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group);
 	if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0)
 		return -1;
 	rsn->mgtk_key_id = 1;

 	if (ieee80211w != NO_MGMT_FRAME_PROTECTION) {
 		rsn->igtk_len = wpa_cipher_key_len(conf.group_mgmt_cipher);
 		if (random_get_bytes(rsn->igtk, rsn->igtk_len) < 0)
 			return -1;
 		rsn->igtk_key_id = 4;

 		/* group mgmt */
 		wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX IGTK",
 				rsn->igtk, rsn->igtk_len);
 		wpa_drv_set_key(rsn->wpa_s,
 				wpa_cipher_to_alg(rsn->mgmt_group_cipher),
 				broadcast_ether_addr,
 				rsn->igtk_key_id, 1,
 				seq, sizeof(seq), rsn->igtk, rsn->igtk_len,
 				KEY_FLAG_GROUP_TX_DEFAULT);
 	}

 	/* group privacy / data frames */
 	wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX MGTK",
 			rsn->mgtk, rsn->mgtk_len);
 	wpa_drv_set_key(rsn->wpa_s, wpa_cipher_to_alg(rsn->group_cipher),
 			broadcast_ether_addr,
 			rsn->mgtk_key_id, 1, seq, sizeof(seq),
 			rsn->mgtk, rsn->mgtk_len, KEY_FLAG_GROUP_TX_DEFAULT);

 	return 0;
 }


 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
 {
 	os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
 	rsn->mgtk_len = 0;
 	os_memset(rsn->igtk, 0, sizeof(rsn->igtk));
 	rsn->igtk_len = 0;
 	if (rsn->auth)
 		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;
 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
 	struct external_pmksa_cache *entry;
 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */

 	mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
 	if (mesh_rsn == NULL)
 		return NULL;
 	mesh_rsn->wpa_s = wpa_s;
 	mesh_rsn->pairwise_cipher = conf->pairwise_cipher;
 	mesh_rsn->group_cipher = conf->group_cipher;
 	mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher;

 	if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr,
 				 conf->ieee80211w, conf->ocv) < 0) {
 		mesh_rsn_deinit(mesh_rsn);
 		os_free(mesh_rsn);
 		return NULL;
 	}

 	bss->wpa_auth = mesh_rsn->auth;

 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
 	while ((entry = dl_list_last(&wpa_s->mesh_external_pmksa_cache,
 				     struct external_pmksa_cache,
 				     list)) != NULL) {
 		int ret;

 		ret = wpa_auth_pmksa_add_entry(bss->wpa_auth,
 					       entry->pmksa_cache);
 		dl_list_del(&entry->list);
 		os_free(entry);

 		if (ret < 0)
 			return NULL;
 	}
 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */

 	ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
 	conf->rsn_ie = (u8 *) ie;
 	conf->rsn_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;
 }


 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
 				     struct wpa_ssid *ssid,
 				     struct sta_info *sta)
 {
 	const char *password;

 	password = ssid->sae_password;
 	if (!password)
 		password = ssid->passphrase;
 	if (!password) {
 		wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
 		return -1;
 	}

 	if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
 		wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
 		return -1;
 	}

 	if (sta->sae->tmp && !sta->sae->tmp->pw_id && ssid->sae_password_id) {
 		sta->sae->tmp->pw_id = os_strdup(ssid->sae_password_id);
 		if (!sta->sae->tmp->pw_id)
 			return -1;
 	}
 	return sae_prepare_commit(wpa_s->own_addr, sta->addr,
 				  (u8 *) password, os_strlen(password),
 				  sta->sae);
 }


 /* initiate new SAE authentication with sta */
 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
 			  struct sta_info *sta)
 {
 	struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
 	struct wpa_ssid *ssid = wpa_s->current_ssid;
 	struct rsn_pmksa_cache_entry *pmksa;
 	unsigned int rnd;
 	int ret;

 	if (!ssid) {
 		wpa_msg(wpa_s, MSG_DEBUG,
 			"AUTH: No current_ssid known to initiate new SAE");
 		return -1;
 	}

 	if (!sta->sae) {
 		sta->sae = os_zalloc(sizeof(*sta->sae));
 		if (sta->sae == NULL)
 			return -1;
 	}

 	pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL);
 	if (pmksa) {
 		if (!sta->wpa_sm)
 			sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth,
 							sta->addr, NULL);
 		if (!sta->wpa_sm) {
 			wpa_printf(MSG_ERROR,
 				   "mesh: Failed to initialize RSN state machine");
 			return -1;
 		}

 		wpa_printf(MSG_DEBUG,
 			   "AUTH: Mesh PMKSA cache entry found for " MACSTR
 			   " - try to use PMKSA caching instead of new SAE authentication",
 			   MAC2STR(sta->addr));
 		wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth,
 					 sta->sae->pmkid, sta->sae->pmk);
 		sae_accept_sta(hapd, sta);
 		sta->mesh_sae_pmksa_caching = 1;
 		return 0;
 	}
 	sta->mesh_sae_pmksa_caching = 0;

 	if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
 		return -1;

 	wpa_msg(wpa_s, MSG_DEBUG,
 		"AUTH: started authentication with SAE peer: " MACSTR,
 		MAC2STR(sta->addr));

 	ret = auth_sae_init_committed(hapd, sta);
 	if (ret)
 		return ret;

 	eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
 	rnd = rand() % MESH_AUTH_TIMEOUT;
 	eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
 			       wpa_s, sta);
 	return 0;
 }


 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
 {
 	os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN);
 }


 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, *addr2;
 	u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context;

 	/*
 	 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite ||
 	 *       min(localMAC, peerMAC) || max(localMAC, peerMAC))
 	 */
 	/* Selected AKM Suite: SAE */
 	RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
 	ptr += RSN_SELECTOR_LEN;

 	if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
 		addr1 = myaddr;
 		addr2 = peer;
 	} else {
 		addr1 = peer;
 		addr2 = myaddr;
 	}
 	os_memcpy(ptr, addr1, ETH_ALEN);
 	ptr += ETH_ALEN;
 	os_memcpy(ptr, 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;
 	u8 *myaddr = wpa_s->own_addr;
 	u8 *peer = sta->addr;
 	u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN];

 	/*
 	 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce,
 	 *  peerNonce) || max(localNonce, peerNonce) || min(localLinkID,
 	 *  peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite ||
 	 *  min(localMAC, peerMAC) || max(localMAC, peerMAC))
 	 */
 	ptr = context;
 	if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) {
 		min = sta->my_nonce;
 		max = sta->peer_nonce;
 	} else {
 		min = sta->peer_nonce;
 		max = sta->my_nonce;
 	}
 	os_memcpy(ptr, min, WPA_NONCE_LEN);
 	ptr += WPA_NONCE_LEN;
 	os_memcpy(ptr, max, WPA_NONCE_LEN);
 	ptr += WPA_NONCE_LEN;

 	if (sta->my_lid < sta->peer_lid) {
 		WPA_PUT_LE16(ptr, sta->my_lid);
 		ptr += 2;
 		WPA_PUT_LE16(ptr, sta->peer_lid);
 		ptr += 2;
 	} else {
 		WPA_PUT_LE16(ptr, sta->peer_lid);
 		ptr += 2;
 		WPA_PUT_LE16(ptr, sta->my_lid);
 		ptr += 2;
 	}

 	/* Selected AKM Suite: SAE */
 	RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
 	ptr += RSN_SELECTOR_LEN;

 	if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
 		min = myaddr;
 		max = peer;
 	} else {
 		min = peer;
 		max = myaddr;
 	}
 	os_memcpy(ptr, min, ETH_ALEN);
 	ptr += ETH_ALEN;
 	os_memcpy(ptr, max, ETH_ALEN);

 	sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher);
 	sha256_prf(sta->sae->pmk, SAE_PMK_LEN,
 		   "Temporal Key Derivation", context, sizeof(context),
 		   sta->mtk, sta->mtk_len);
 	return 0;
 }


 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
 {
 	if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) {
 		wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
 		/* TODO: How to handle this more cleanly? */
 	}
 	os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN);
 	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, *pos, *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;
 	size_t len;

 	len = sizeof(*ampe);
 	if (cat[1] == PLINK_OPEN)
 		len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4;
 	if (cat[1] == PLINK_OPEN && rsn->igtk_len)
 		len += 2 + 6 + rsn->igtk_len;

 	if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) {
 		wpa_printf(MSG_ERROR, "protect frame: buffer too small");
 		return -EINVAL;
 	}

 	ampe_ie = os_zalloc(2 + len);
 	if (!ampe_ie) {
 		wpa_printf(MSG_ERROR, "protect frame: out of memory");
 		return -ENOMEM;
 	}

 	/*  IE: AMPE */
 	ampe_ie[0] = WLAN_EID_AMPE;
 	ampe_ie[1] = len;
 	ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);

 	RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
 			 RSN_CIPHER_SUITE_CCMP);
 	os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN);
 	os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN);

 	pos = (u8 *) (ampe + 1);
 	if (cat[1] != PLINK_OPEN)
 		goto skip_keys;

 	/* TODO: Key Replay Counter[8] optionally for
 	 * Mesh Group Key Inform/Acknowledge frames */

 	/* TODO: static mgtk for now since we don't support rekeying! */
 	/*
 	 * GTKdata[variable]:
 	 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
 	 */
 	os_memcpy(pos, rsn->mgtk, rsn->mgtk_len);
 	pos += rsn->mgtk_len;
 	wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos);
 	pos += WPA_KEY_RSC_LEN;
 	/* Use fixed GTKExpirationTime for now */
 	WPA_PUT_LE32(pos, 0xffffffff);
 	pos += 4;

 	/*
 	 * IGTKdata[variable]:
 	 * Key ID[2], IPN[6], IGTK[variable]
 	 */
 	if (rsn->igtk_len) {
 		WPA_PUT_LE16(pos, rsn->igtk_key_id);
 		pos += 2;
 		wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos);
 		pos += 6;
 		os_memcpy(pos, rsn->igtk, rsn->igtk_len);
 	}

 skip_keys:
 	wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element",
 			ampe_ie, 2 + len);

 	/* IE: MIC */
 	wpabuf_put_u8(buf, WLAN_EID_MIC);
 	wpabuf_put_u8(buf, AES_BLOCK_SIZE);
 	/* MIC field is output ciphertext */

 	/* encrypt after MIC */
 	mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE);

 	if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3,
 			    aad, aad_len, mic_payload)) {
 		wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
 		ret = -ENOMEM;
 	}

 	os_free(ampe_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 *chosen_pmk,
 			  const u8 *start, size_t elems_len)
 {
 	int ret = 0;
 	struct ieee80211_ampe_ie *ampe;
 	u8 null_nonce[WPA_NONCE_LEN] = {};
 	u8 ampe_eid;
 	u8 ampe_ie_len;
 	u8 *ampe_buf, *crypt = NULL, *pos, *end;
 	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 ? (elems->mic - 2) - cat : 0 };
 	size_t key_len;

 	if (!sta->sae) {
 		struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];

 		if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) {
 			wpa_printf(MSG_INFO,
 				   "Mesh RSN: SAE is not prepared yet");
 			return -1;
 		}
 		mesh_rsn_auth_sae_sta(wpa_s, sta);
 	}

 	if (chosen_pmk &&
 	    (!sta->sae ||
 	     os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN) != 0)) {
 		wpa_msg(wpa_s, MSG_DEBUG,
 			"Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
 		return -1;
 	}

 	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 + AES_BLOCK_SIZE) {
 		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, sizeof(sta->aek), crypt, crypt_len, 3,
 			    aad, aad_len, ampe_buf)) {
 		wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
 		ret = -2;
 		goto free;
 	}

 	crypt_len -= AES_BLOCK_SIZE;
 	wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element",
 			ampe_buf, crypt_len);

 	ampe_eid = *ampe_buf++;
 	ampe_ie_len = *ampe_buf++;

 	if (ampe_eid != WLAN_EID_AMPE ||
 	    (size_t) 2 + ampe_ie_len > crypt_len ||
 	    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;
 	pos = (u8 *) (ampe + 1);
 	end = ampe_buf + ampe_ie_len;
 	if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 &&
 	    os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 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));

 	/* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge
 	 * frames */

 	/*
 	 * GTKdata shall not be included in Mesh Peering Confirm. While the
 	 * standard does not state the same about IGTKdata, that same constraint
 	 * needs to apply for it. It makes no sense to include the keys in Mesh
 	 * Peering Close frames either, so while the standard does not seem to
 	 * have a shall statement for these, they are described without
 	 * mentioning GTKdata.
 	 *
 	 * An earlier implementation used to add GTKdata to both Mesh Peering
 	 * Open and Mesh Peering Confirm frames, so ignore the possibly present
 	 * GTKdata frame without rejecting the frame as a backwards
 	 * compatibility mechanism.
 	 */
 	if (cat[1] != PLINK_OPEN) {
 		if (end > pos) {
 			wpa_hexdump_key(MSG_DEBUG,
 					"mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close",
 					pos, end - pos);
 		}
 		goto free;
 	}

 	/*
 	 * GTKdata[variable]:
 	 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
 	 */
 	sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */
 	key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher);
 	if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) {
 		wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element");
 		ret = -1;
 		goto free;
 	}
 	sta->mgtk_len = key_len;
 	os_memcpy(sta->mgtk, pos, sta->mgtk_len);
 	wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK",
 			sta->mgtk, sta->mgtk_len);
 	pos += sta->mgtk_len;
 	wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC",
 		    pos, WPA_KEY_RSC_LEN);
 	os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc));
 	pos += WPA_KEY_RSC_LEN;
 	wpa_printf(MSG_DEBUG,
 		   "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds",
 		   WPA_GET_LE32(pos));
 	pos += 4;

 	/*
 	 * IGTKdata[variable]:
 	 * Key ID[2], IPN[6], IGTK[variable]
 	 */
 	key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher);
 	if (end - pos >= (int) (2 + 6 + key_len)) {
 		sta->igtk_key_id = WPA_GET_LE16(pos);
 		wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u",
 			   sta->igtk_key_id);
 		pos += 2;
 		os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc));
 		wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN",
 			    sta->igtk_rsc, sizeof(sta->igtk_rsc));
 		pos += 6;
 		os_memcpy(sta->igtk, pos, key_len);
 		sta->igtk_len = key_len;
 		wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK",
 				sta->igtk, sta->igtk_len);
 	}

 free:
 	os_free(crypt);
 	return ret;
 }
	/*
	* 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 "utils/eloop.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 "ap/ieee802_11.h"
	#include "wpa_supplicant_i.h"
	#include "driver_i.h"
	#include "wpas_glue.h"
	#include "mesh_mpm.h"
	#include "mesh_rsn.h"

	#define MESH_AUTH_TIMEOUT 10
	#define MESH_AUTH_RETRY 3

	void mesh_auth_timer(void eloop_ctx, void user_data)
	{
	struct wpa_supplicant *wpa_s = eloop_ctx;
	struct sta_info *sta = user_data;
	struct hostapd_data *hapd;

	if (sta->sae->state != SAE_ACCEPTED) {
	wpa_printf(MSG_DEBUG, "AUTH: Re-authenticate with " MACSTR
	" (attempt %d) ",
	MAC2STR(sta->addr), sta->sae_auth_retry);
	wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_FAILURE "addr=" MACSTR,
	MAC2STR(sta->addr));
	if (sta->sae_auth_retry < MESH_AUTH_RETRY) {
	mesh_rsn_auth_sae_sta(wpa_s, sta);
	} else {
	hapd = wpa_s->ifmsh->bss[0];

	if (sta->sae_auth_retry > MESH_AUTH_RETRY) {
	ap_free_sta(hapd, sta);
	return;
	}

	/* block the STA if exceeded the number of attempts */
	wpa_mesh_set_plink_state(wpa_s, sta, PLINK_BLOCKED);
	sta->sae->state = SAE_NOTHING;
	wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_BLOCKED "addr="
	MACSTR " duration=%d",
	MAC2STR(sta->addr),
	hapd->conf->ap_max_inactivity);
	}
	sta->sae_auth_retry++;
	}
	}


	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,
	size_t psk_len, int vlan_id)
	{
	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);

	if (psk_len)
	*psk_len = PMK_LEN;
	if (vlan_id)
	*vlan_id = 0;
	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,
	enum key_flag key_flag)
	{
	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, key_flag);
	}


	static int auth_start_ampe(void ctx, const u8 addr)
	{
	struct mesh_rsn *mesh_rsn = ctx;
	struct hostapd_data *hapd;
	struct sta_info *sta;

	if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
	return -1;

	hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
	sta = ap_get_sta(hapd, addr);
	if (sta)
	eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);

	mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
	return 0;
	}


	static int __mesh_rsn_auth_init(struct mesh_rsn rsn, const u8 addr,
	enum mfp_options ieee80211w, int ocv)
	{
	struct wpa_auth_config conf;
	static const struct wpa_auth_callbacks cb = {
	.logger = auth_logger,
	.get_psk = auth_get_psk,
	.set_key = auth_set_key,
	.start_ampe = auth_start_ampe,
	};
	u8 seq[6] = {};

	wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");

	os_memset(&conf, 0, sizeof(conf));
	conf.wpa = WPA_PROTO_RSN;
	conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
	conf.wpa_pairwise = rsn->pairwise_cipher;
	conf.rsn_pairwise = rsn->pairwise_cipher;
	conf.wpa_group = rsn->group_cipher;
	conf.eapol_version = 0;
	conf.wpa_group_rekey = -1;
	conf.wpa_group_update_count = 4;
	conf.wpa_pairwise_update_count = 4;
	conf.ieee80211w = ieee80211w;
	if (ieee80211w != NO_MGMT_FRAME_PROTECTION)
	conf.group_mgmt_cipher = rsn->mgmt_group_cipher;
	#ifdef CONFIG_OCV
	conf.ocv = ocv;
	#endif /* CONFIG_OCV */

	rsn->auth = wpa_init(addr, &conf, &cb, rsn);
	if (rsn->auth == NULL) {
	wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
	return -1;
	}

	/* TODO: support rekeying */
	rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group);
	if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0)
	return -1;
	rsn->mgtk_key_id = 1;

	if (ieee80211w != NO_MGMT_FRAME_PROTECTION) {
	rsn->igtk_len = wpa_cipher_key_len(conf.group_mgmt_cipher);
	if (random_get_bytes(rsn->igtk, rsn->igtk_len) < 0)
	return -1;
	rsn->igtk_key_id = 4;

	/* group mgmt */
	wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX IGTK",
	rsn->igtk, rsn->igtk_len);
	wpa_drv_set_key(rsn->wpa_s,
	wpa_cipher_to_alg(rsn->mgmt_group_cipher),
	broadcast_ether_addr,
	rsn->igtk_key_id, 1,
	seq, sizeof(seq), rsn->igtk, rsn->igtk_len,
	KEY_FLAG_GROUP_TX_DEFAULT);
	}

	/* group privacy / data frames */
	wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX MGTK",
	rsn->mgtk, rsn->mgtk_len);
	wpa_drv_set_key(rsn->wpa_s, wpa_cipher_to_alg(rsn->group_cipher),
	broadcast_ether_addr,
	rsn->mgtk_key_id, 1, seq, sizeof(seq),
	rsn->mgtk, rsn->mgtk_len, KEY_FLAG_GROUP_TX_DEFAULT);

	return 0;
	}


	static void mesh_rsn_deinit(struct mesh_rsn *rsn)
	{
	os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
	rsn->mgtk_len = 0;
	os_memset(rsn->igtk, 0, sizeof(rsn->igtk));
	rsn->igtk_len = 0;
	if (rsn->auth)
	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;
	#ifdef CONFIG_PMKSA_CACHE_EXTERNAL
	struct external_pmksa_cache *entry;
	#endif /* CONFIG_PMKSA_CACHE_EXTERNAL */

	mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
	if (mesh_rsn == NULL)
	return NULL;
	mesh_rsn->wpa_s = wpa_s;
	mesh_rsn->pairwise_cipher = conf->pairwise_cipher;
	mesh_rsn->group_cipher = conf->group_cipher;
	mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher;

	if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr,
	conf->ieee80211w, conf->ocv) < 0) {
	mesh_rsn_deinit(mesh_rsn);
	os_free(mesh_rsn);
	return NULL;
	}

	bss->wpa_auth = mesh_rsn->auth;

	#ifdef CONFIG_PMKSA_CACHE_EXTERNAL
	while ((entry = dl_list_last(&wpa_s->mesh_external_pmksa_cache,
	struct external_pmksa_cache,
	list)) != NULL) {
	int ret;

	ret = wpa_auth_pmksa_add_entry(bss->wpa_auth,
	entry->pmksa_cache);
	dl_list_del(&entry->list);
	os_free(entry);

	if (ret < 0)
	return NULL;
	}
	#endif /* CONFIG_PMKSA_CACHE_EXTERNAL */

	ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
	conf->rsn_ie = (u8 *) ie;
	conf->rsn_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;
	}


	static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
	struct wpa_ssid *ssid,
	struct sta_info *sta)
	{
	const char *password;

	password = ssid->sae_password;
	if (!password)
	password = ssid->passphrase;
	if (!password) {
	wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
	return -1;
	}

	if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
	wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
	return -1;
	}

	if (sta->sae->tmp && !sta->sae->tmp->pw_id && ssid->sae_password_id) {
	sta->sae->tmp->pw_id = os_strdup(ssid->sae_password_id);
	if (!sta->sae->tmp->pw_id)
	return -1;
	}
	return sae_prepare_commit(wpa_s->own_addr, sta->addr,
	(u8 *) password, os_strlen(password),
	sta->sae);
	}


	/* initiate new SAE authentication with sta */
	int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
	struct sta_info *sta)
	{
	struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
	struct wpa_ssid *ssid = wpa_s->current_ssid;
	struct rsn_pmksa_cache_entry *pmksa;
	unsigned int rnd;
	int ret;

	if (!ssid) {
	wpa_msg(wpa_s, MSG_DEBUG,
	"AUTH: No current_ssid known to initiate new SAE");
	return -1;
	}

	if (!sta->sae) {
	sta->sae = os_zalloc(sizeof(*sta->sae));
	if (sta->sae == NULL)
	return -1;
	}

	pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL);
	if (pmksa) {
	if (!sta->wpa_sm)
	sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth,
	sta->addr, NULL);
	if (!sta->wpa_sm) {
	wpa_printf(MSG_ERROR,
	"mesh: Failed to initialize RSN state machine");
	return -1;
	}

	wpa_printf(MSG_DEBUG,
	"AUTH: Mesh PMKSA cache entry found for " MACSTR
	" - try to use PMKSA caching instead of new SAE authentication",
	MAC2STR(sta->addr));
	wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth,
	sta->sae->pmkid, sta->sae->pmk);
	sae_accept_sta(hapd, sta);
	sta->mesh_sae_pmksa_caching = 1;
	return 0;
	}
	sta->mesh_sae_pmksa_caching = 0;

	if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
	return -1;

	wpa_msg(wpa_s, MSG_DEBUG,
	"AUTH: started authentication with SAE peer: " MACSTR,
	MAC2STR(sta->addr));

	ret = auth_sae_init_committed(hapd, sta);
	if (ret)
	return ret;

	eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
	rnd = rand() % MESH_AUTH_TIMEOUT;
	eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
	wpa_s, sta);
	return 0;
	}


	void mesh_rsn_get_pmkid(struct mesh_rsn rsn, struct sta_info sta, u8 *pmkid)
	{
	os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN);
	}


	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, addr2;
	u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context;

	/*
	* AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite \|\|
	* min(localMAC, peerMAC) \|\| max(localMAC, peerMAC))
	*/
	/* Selected AKM Suite: SAE */
	RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
	ptr += RSN_SELECTOR_LEN;

	if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
	addr1 = myaddr;
	addr2 = peer;
	} else {
	addr1 = peer;
	addr2 = myaddr;
	}
	os_memcpy(ptr, addr1, ETH_ALEN);
	ptr += ETH_ALEN;
	os_memcpy(ptr, 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;
	u8 *myaddr = wpa_s->own_addr;
	u8 *peer = sta->addr;
	u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN];

	/*
	* MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce,
	* peerNonce) \|\| max(localNonce, peerNonce) \|\| min(localLinkID,
	* peerLinkID) \|\| max(localLinkID, peerLinkID) \|\| Selected AKM Suite \|\|
	* min(localMAC, peerMAC) \|\| max(localMAC, peerMAC))
	*/
	ptr = context;
	if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) {
	min = sta->my_nonce;
	max = sta->peer_nonce;
	} else {
	min = sta->peer_nonce;
	max = sta->my_nonce;
	}
	os_memcpy(ptr, min, WPA_NONCE_LEN);
	ptr += WPA_NONCE_LEN;
	os_memcpy(ptr, max, WPA_NONCE_LEN);
	ptr += WPA_NONCE_LEN;

	if (sta->my_lid < sta->peer_lid) {
	WPA_PUT_LE16(ptr, sta->my_lid);
	ptr += 2;
	WPA_PUT_LE16(ptr, sta->peer_lid);
	ptr += 2;
	} else {
	WPA_PUT_LE16(ptr, sta->peer_lid);
	ptr += 2;
	WPA_PUT_LE16(ptr, sta->my_lid);
	ptr += 2;
	}

	/* Selected AKM Suite: SAE */
	RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
	ptr += RSN_SELECTOR_LEN;

	if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
	min = myaddr;
	max = peer;
	} else {
	min = peer;
	max = myaddr;
	}
	os_memcpy(ptr, min, ETH_ALEN);
	ptr += ETH_ALEN;
	os_memcpy(ptr, max, ETH_ALEN);

	sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher);
	sha256_prf(sta->sae->pmk, SAE_PMK_LEN,
	"Temporal Key Derivation", context, sizeof(context),
	sta->mtk, sta->mtk_len);
	return 0;
	}


	void mesh_rsn_init_ampe_sta(struct wpa_supplicant wpa_s, struct sta_info sta)
	{
	if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) {
	wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
	/* TODO: How to handle this more cleanly? */
	}
	os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN);
	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, pos, *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;
	size_t len;

	len = sizeof(*ampe);
	if (cat[1] == PLINK_OPEN)
	len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4;
	if (cat[1] == PLINK_OPEN && rsn->igtk_len)
	len += 2 + 6 + rsn->igtk_len;

	if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) {
	wpa_printf(MSG_ERROR, "protect frame: buffer too small");
	return -EINVAL;
	}

	ampe_ie = os_zalloc(2 + len);
	if (!ampe_ie) {
	wpa_printf(MSG_ERROR, "protect frame: out of memory");
	return -ENOMEM;
	}

	/* IE: AMPE */
	ampe_ie[0] = WLAN_EID_AMPE;
	ampe_ie[1] = len;
	ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);

	RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
	RSN_CIPHER_SUITE_CCMP);
	os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN);
	os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN);

	pos = (u8 *) (ampe + 1);
	if (cat[1] != PLINK_OPEN)
	goto skip_keys;

	/* TODO: Key Replay Counter[8] optionally for
	* Mesh Group Key Inform/Acknowledge frames */

	/* TODO: static mgtk for now since we don't support rekeying! */
	/*
	* GTKdata[variable]:
	* MGTK[variable] \|\| Key RSC[8] \|\| GTKExpirationTime[4]
	*/
	os_memcpy(pos, rsn->mgtk, rsn->mgtk_len);
	pos += rsn->mgtk_len;
	wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos);
	pos += WPA_KEY_RSC_LEN;
	/* Use fixed GTKExpirationTime for now */
	WPA_PUT_LE32(pos, 0xffffffff);
	pos += 4;

	/*
	* IGTKdata[variable]:
	* Key ID[2], IPN[6], IGTK[variable]
	*/
	if (rsn->igtk_len) {
	WPA_PUT_LE16(pos, rsn->igtk_key_id);
	pos += 2;
	wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos);
	pos += 6;
	os_memcpy(pos, rsn->igtk, rsn->igtk_len);
	}

	skip_keys:
	wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element",
	ampe_ie, 2 + len);

	/* IE: MIC */
	wpabuf_put_u8(buf, WLAN_EID_MIC);
	wpabuf_put_u8(buf, AES_BLOCK_SIZE);
	/* MIC field is output ciphertext */

	/* encrypt after MIC */
	mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE);

	if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3,
	aad, aad_len, mic_payload)) {
	wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
	ret = -ENOMEM;
	}

	os_free(ampe_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 *chosen_pmk,
	const u8 *start, size_t elems_len)
	{
	int ret = 0;
	struct ieee80211_ampe_ie *ampe;
	u8 null_nonce[WPA_NONCE_LEN] = {};
	u8 ampe_eid;
	u8 ampe_ie_len;
	u8 ampe_buf, crypt = NULL, pos, end;
	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 ? (elems->mic - 2) - cat : 0 };
	size_t key_len;

	if (!sta->sae) {
	struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];

	if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) {
	wpa_printf(MSG_INFO,
	"Mesh RSN: SAE is not prepared yet");
	return -1;
	}
	mesh_rsn_auth_sae_sta(wpa_s, sta);
	}

	if (chosen_pmk &&
	(!sta->sae \|\|
	os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN) != 0)) {
	wpa_msg(wpa_s, MSG_DEBUG,
	"Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
	return -1;
	}

	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 + AES_BLOCK_SIZE) {
	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, sizeof(sta->aek), crypt, crypt_len, 3,
	aad, aad_len, ampe_buf)) {
	wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
	ret = -2;
	goto free;
	}

	crypt_len -= AES_BLOCK_SIZE;
	wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element",
	ampe_buf, crypt_len);

	ampe_eid = *ampe_buf++;
	ampe_ie_len = *ampe_buf++;

	if (ampe_eid != WLAN_EID_AMPE \|\|
	(size_t) 2 + ampe_ie_len > crypt_len \|\|
	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;
	pos = (u8 *) (ampe + 1);
	end = ampe_buf + ampe_ie_len;
	if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 &&
	os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 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));

	/* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge
	* frames */

	/*
	* GTKdata shall not be included in Mesh Peering Confirm. While the
	* standard does not state the same about IGTKdata, that same constraint
	* needs to apply for it. It makes no sense to include the keys in Mesh
	* Peering Close frames either, so while the standard does not seem to
	* have a shall statement for these, they are described without
	* mentioning GTKdata.
	*
	* An earlier implementation used to add GTKdata to both Mesh Peering
	* Open and Mesh Peering Confirm frames, so ignore the possibly present
	* GTKdata frame without rejecting the frame as a backwards
	* compatibility mechanism.
	*/
	if (cat[1] != PLINK_OPEN) {
	if (end > pos) {
	wpa_hexdump_key(MSG_DEBUG,
	"mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close",
	pos, end - pos);
	}
	goto free;
	}

	/*
	* GTKdata[variable]:
	* MGTK[variable] \|\| Key RSC[8] \|\| GTKExpirationTime[4]
	*/
	sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */
	key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher);
	if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) {
	wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element");
	ret = -1;
	goto free;
	}
	sta->mgtk_len = key_len;
	os_memcpy(sta->mgtk, pos, sta->mgtk_len);
	wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK",
	sta->mgtk, sta->mgtk_len);
	pos += sta->mgtk_len;
	wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC",
	pos, WPA_KEY_RSC_LEN);
	os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc));
	pos += WPA_KEY_RSC_LEN;
	wpa_printf(MSG_DEBUG,
	"mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds",
	WPA_GET_LE32(pos));
	pos += 4;

	/*
	* IGTKdata[variable]:
	* Key ID[2], IPN[6], IGTK[variable]
	*/
	key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher);
	if (end - pos >= (int) (2 + 6 + key_len)) {
	sta->igtk_key_id = WPA_GET_LE16(pos);
	wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u",
	sta->igtk_key_id);
	pos += 2;
	os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc));
	wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN",
	sta->igtk_rsc, sizeof(sta->igtk_rsc));
	pos += 6;
	os_memcpy(sta->igtk, pos, key_len);
	sta->igtk_len = key_len;
	wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK",
	sta->igtk, sta->igtk_len);
	}

	free:
	os_free(crypt);
	return ret;
	}