ibss_rsn.c

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/*
 * wpa_supplicant - IBSS RSN
 * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "l2_packet/l2_packet.h"
#include "rsn_supp/wpa.h"
#include "rsn_supp/wpa_ie.h"
#include "ap/wpa_auth.h"
#include "wpa_supplicant_i.h"
#include "driver_i.h"
#include "ibss_rsn.h"


static void ibss_rsn_free(struct ibss_rsn_peer *peer)
{
        wpa_auth_sta_deinit(peer->auth);
        wpa_sm_deinit(peer->supp);
        os_free(peer);
}


static void supp_set_state(void *ctx, enum wpa_states state)
{
        struct ibss_rsn_peer *peer = ctx;
        peer->supp_state = state;
}


static int supp_ether_send(void *ctx, const u8 *dest, u16 proto, const u8 *buf,
                           size_t len)
{
        struct ibss_rsn_peer *peer = ctx;
        struct wpa_supplicant *wpa_s = peer->ibss_rsn->wpa_s;

        wpa_printf(MSG_DEBUG, "SUPP: %s(dest=" MACSTR " proto=0x%04x "
                   "len=%lu)",
                   __func__, MAC2STR(dest), proto, (unsigned long) len);

        if (wpa_s->l2)
                return l2_packet_send(wpa_s->l2, dest, proto, buf, len);

        return wpa_drv_send_eapol(wpa_s, dest, proto, buf, len);
}


static u8 * supp_alloc_eapol(void *ctx, u8 type, const void *data,
                             u16 data_len, size_t *msg_len, void **data_pos)
{
        struct ieee802_1x_hdr *hdr;

        wpa_printf(MSG_DEBUG, "SUPP: %s(type=%d data_len=%d)",
                   __func__, type, data_len);

        *msg_len = sizeof(*hdr) + data_len;
        hdr = os_malloc(*msg_len);
        if (hdr == NULL)
                return NULL;

        hdr->version = 2;
        hdr->type = type;
        hdr->length = host_to_be16(data_len);

        if (data)
                os_memcpy(hdr + 1, data, data_len);
        else
                os_memset(hdr + 1, 0, data_len);

        if (data_pos)
                *data_pos = hdr + 1;

        return (u8 *) hdr;
}


static int supp_get_beacon_ie(void *ctx)
{
        struct ibss_rsn_peer *peer = ctx;

        wpa_printf(MSG_DEBUG, "SUPP: %s", __func__);
        /* TODO: get correct RSN IE */
        return wpa_sm_set_ap_rsn_ie(peer->supp,
                                    (u8 *) "\x30\x14\x01\x00"
                                    "\x00\x0f\xac\x04"
                                    "\x01\x00\x00\x0f\xac\x04"
                                    "\x01\x00\x00\x0f\xac\x02"
                                    "\x00\x00", 22);
}


static int supp_set_key(void *ctx, enum wpa_alg alg,
                        const u8 *addr, int key_idx, int set_tx,
                        const u8 *seq, size_t seq_len,
                        const u8 *key, size_t key_len)
{
        struct ibss_rsn_peer *peer = ctx;

        wpa_printf(MSG_DEBUG, "SUPP: %s(alg=%d addr=" MACSTR " key_idx=%d "
                   "set_tx=%d)",
                   __func__, alg, MAC2STR(addr), key_idx, set_tx);
        wpa_hexdump(MSG_DEBUG, "SUPP: set_key - seq", seq, seq_len);
        wpa_hexdump_key(MSG_DEBUG, "SUPP: set_key - key", key, key_len);

        if (key_idx == 0) {
                /*
                 * In IBSS RSN, the pairwise key from the 4-way handshake
                 * initiated by the peer with highest MAC address is used.
                 */
                if (os_memcmp(peer->ibss_rsn->wpa_s->own_addr, peer->addr,
                              ETH_ALEN) > 0) {
                        wpa_printf(MSG_DEBUG, "SUPP: Do not use this PTK");
                        return 0;
                }
        }

        return wpa_drv_set_key(peer->ibss_rsn->wpa_s, alg, addr, key_idx,
                               set_tx, seq, seq_len, key, key_len);
}


static void * supp_get_network_ctx(void *ctx)
{
        struct ibss_rsn_peer *peer = ctx;
        return wpa_supplicant_get_ssid(peer->ibss_rsn->wpa_s);
}


static int supp_mlme_setprotection(void *ctx, const u8 *addr,
                                   int protection_type, int key_type)
{
        wpa_printf(MSG_DEBUG, "SUPP: %s(addr=" MACSTR " protection_type=%d "
                   "key_type=%d)",
                   __func__, MAC2STR(addr), protection_type, key_type);
        return 0;
}


static void supp_cancel_auth_timeout(void *ctx)
{
        wpa_printf(MSG_DEBUG, "SUPP: %s", __func__);
}


int ibss_rsn_supp_init(struct ibss_rsn_peer *peer, const u8 *own_addr,
                       const u8 *psk)
{
        struct wpa_sm_ctx *ctx = os_zalloc(sizeof(*ctx));
        if (ctx == NULL)
                return -1;

        ctx->ctx = peer;
        ctx->msg_ctx = peer->ibss_rsn->wpa_s;
        ctx->set_state = supp_set_state;
        ctx->ether_send = supp_ether_send;
        ctx->get_beacon_ie = supp_get_beacon_ie;
        ctx->alloc_eapol = supp_alloc_eapol;
        ctx->set_key = supp_set_key;
        ctx->get_network_ctx = supp_get_network_ctx;
        ctx->mlme_setprotection = supp_mlme_setprotection;
        ctx->cancel_auth_timeout = supp_cancel_auth_timeout;
        peer->supp = wpa_sm_init(ctx);
        if (peer->supp == NULL) {
                wpa_printf(MSG_DEBUG, "SUPP: wpa_sm_init() failed");
                return -1;
        }

        wpa_sm_set_own_addr(peer->supp, own_addr);
        wpa_sm_set_param(peer->supp, WPA_PARAM_RSN_ENABLED, 1);
        wpa_sm_set_param(peer->supp, WPA_PARAM_PROTO, WPA_PROTO_RSN);
        wpa_sm_set_param(peer->supp, WPA_PARAM_PAIRWISE, WPA_CIPHER_CCMP);
        wpa_sm_set_param(peer->supp, WPA_PARAM_GROUP, WPA_CIPHER_CCMP);
        wpa_sm_set_param(peer->supp, WPA_PARAM_KEY_MGMT, WPA_KEY_MGMT_PSK);
        wpa_sm_set_pmk(peer->supp, psk, PMK_LEN);

        peer->supp_ie_len = sizeof(peer->supp_ie);
        if (wpa_sm_set_assoc_wpa_ie_default(peer->supp, peer->supp_ie,
                                            &peer->supp_ie_len) < 0) {
                wpa_printf(MSG_DEBUG, "SUPP: wpa_sm_set_assoc_wpa_ie_default()"
                           " failed");
                return -1;
        }

        wpa_sm_notify_assoc(peer->supp, peer->addr);

        return 0;
}


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 *prev_psk)
{
        struct ibss_rsn *ibss_rsn = ctx;
        wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
                   __func__, MAC2STR(addr), prev_psk);
        if (prev_psk)
                return NULL;
        return ibss_rsn->psk;
}


static int auth_send_eapol(void *ctx, const u8 *addr, const u8 *data,
                           size_t data_len, int encrypt)
{
        struct ibss_rsn *ibss_rsn = ctx;
        struct wpa_supplicant *wpa_s = ibss_rsn->wpa_s;

        wpa_printf(MSG_DEBUG, "AUTH: %s(addr=" MACSTR " data_len=%lu "
                   "encrypt=%d)",
                   __func__, MAC2STR(addr), (unsigned long) data_len, encrypt);

        if (wpa_s->l2)
                return l2_packet_send(wpa_s->l2, addr, ETH_P_EAPOL, data,
                                      data_len);

        return wpa_drv_send_eapol(wpa_s, addr, ETH_P_EAPOL, data, data_len);
}


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 ibss_rsn *ibss_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);

        if (idx == 0) {
                /*
                 * In IBSS RSN, the pairwise key from the 4-way handshake
                 * initiated by the peer with highest MAC address is used.
                 */
                if (addr == NULL ||
                    os_memcmp(ibss_rsn->wpa_s->own_addr, addr, ETH_ALEN) < 0) {
                        wpa_printf(MSG_DEBUG, "AUTH: Do not use this PTK");
                        return 0;
                }
        }

        return wpa_drv_set_key(ibss_rsn->wpa_s, alg, addr, idx,
                               1, seq, 6, key, key_len);
}


static int ibss_rsn_auth_init_group(struct ibss_rsn *ibss_rsn,
                                    const u8 *own_addr)
{
        struct wpa_auth_config conf;
        struct wpa_auth_callbacks cb;

        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_PSK;
        conf.wpa_pairwise = WPA_CIPHER_CCMP;
        conf.rsn_pairwise = WPA_CIPHER_CCMP;
        conf.wpa_group = WPA_CIPHER_CCMP;
        conf.eapol_version = 2;

        os_memset(&cb, 0, sizeof(cb));
        cb.ctx = ibss_rsn;
        cb.logger = auth_logger;
        cb.send_eapol = auth_send_eapol;
        cb.get_psk = auth_get_psk;
        cb.set_key = auth_set_key;

        ibss_rsn->auth_group = wpa_init(own_addr, &conf, &cb);
        if (ibss_rsn->auth_group == NULL) {
                wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
                return -1;
        }

        return 0;
}


static int ibss_rsn_auth_init(struct ibss_rsn *ibss_rsn,
                              struct ibss_rsn_peer *peer)
{
        peer->auth = wpa_auth_sta_init(ibss_rsn->auth_group, peer->addr);
        if (peer->auth == NULL) {
                wpa_printf(MSG_DEBUG, "AUTH: wpa_auth_sta_init() failed");
                return -1;
        }

        /* TODO: get peer RSN IE with Probe Request */
        if (wpa_validate_wpa_ie(ibss_rsn->auth_group, peer->auth,
                                (u8 *) "\x30\x14\x01\x00"
                                "\x00\x0f\xac\x04"
                                "\x01\x00\x00\x0f\xac\x04"
                                "\x01\x00\x00\x0f\xac\x02"
                                "\x00\x00", 22, NULL, 0) !=
            WPA_IE_OK) {
                wpa_printf(MSG_DEBUG, "AUTH: wpa_validate_wpa_ie() failed");
                return -1;
        }

        if (wpa_auth_sm_event(peer->auth, WPA_ASSOC))
                return -1;

        if (wpa_auth_sta_associated(ibss_rsn->auth_group, peer->auth))
                return -1;

        return 0;
}


int ibss_rsn_start(struct ibss_rsn *ibss_rsn, const u8 *addr)
{
        struct ibss_rsn_peer *peer;

        wpa_printf(MSG_DEBUG, "RSN: Starting IBSS Authenticator and "
                   "Supplicant for peer " MACSTR, MAC2STR(addr));

        peer = os_zalloc(sizeof(*peer));
        if (peer == NULL)
                return -1;

        peer->ibss_rsn = ibss_rsn;
        os_memcpy(peer->addr, addr, ETH_ALEN);

        if (ibss_rsn_supp_init(peer, ibss_rsn->wpa_s->own_addr, ibss_rsn->psk)
            < 0) {
                ibss_rsn_free(peer);
                return -1;
        }

        if (ibss_rsn_auth_init(ibss_rsn, peer) < 0) {
                ibss_rsn_free(peer);
                return -1;
        }

        peer->next = ibss_rsn->peers;
        ibss_rsn->peers = peer;

        return 0;
}


struct ibss_rsn * ibss_rsn_init(struct wpa_supplicant *wpa_s)
{
        struct ibss_rsn *ibss_rsn;

        ibss_rsn = os_zalloc(sizeof(*ibss_rsn));
        if (ibss_rsn == NULL)
                return NULL;
        ibss_rsn->wpa_s = wpa_s;

        if (ibss_rsn_auth_init_group(ibss_rsn, wpa_s->own_addr) < 0) {
                ibss_rsn_deinit(ibss_rsn);
                return NULL;
        }

        return ibss_rsn;
}


void ibss_rsn_deinit(struct ibss_rsn *ibss_rsn)
{
        struct ibss_rsn_peer *peer, *prev;

        if (ibss_rsn == NULL)
                return;

        peer = ibss_rsn->peers;
        while (peer) {
                prev = peer;
                peer = peer->next;
                ibss_rsn_free(prev);
        }

        wpa_deinit(ibss_rsn->auth_group);
        os_free(ibss_rsn);

}


static int ibss_rsn_eapol_dst_supp(const u8 *buf, size_t len)
{
        const struct ieee802_1x_hdr *hdr;
        const struct wpa_eapol_key *key;
        u16 key_info;
        size_t plen;

        /* TODO: Support other EAPOL packets than just EAPOL-Key */

        if (len < sizeof(*hdr) + sizeof(*key))
                return -1;

        hdr = (const struct ieee802_1x_hdr *) buf;
        key = (const struct wpa_eapol_key *) (hdr + 1);
        plen = be_to_host16(hdr->length);

        if (hdr->version < EAPOL_VERSION) {
                /* TODO: backwards compatibility */
        }
        if (hdr->type != IEEE802_1X_TYPE_EAPOL_KEY) {
                wpa_printf(MSG_DEBUG, "RSN: EAPOL frame (type %u) discarded, "
                        "not a Key frame", hdr->type);
                return -1;
        }
        if (plen > len - sizeof(*hdr) || plen < sizeof(*key)) {
                wpa_printf(MSG_DEBUG, "RSN: EAPOL frame payload size %lu "
                           "invalid (frame size %lu)",
                           (unsigned long) plen, (unsigned long) len);
                return -1;
        }

        if (key->type != EAPOL_KEY_TYPE_RSN) {
                wpa_printf(MSG_DEBUG, "RSN: EAPOL-Key type (%d) unknown, "
                           "discarded", key->type);
                return -1;
        }

        key_info = WPA_GET_BE16(key->key_info);

        return !!(key_info & WPA_KEY_INFO_ACK);
}


static int ibss_rsn_process_rx_eapol(struct ibss_rsn *ibss_rsn,
                                     struct ibss_rsn_peer *peer,
                                     const u8 *buf, size_t len)
{
        int supp;
        u8 *tmp;

        supp = ibss_rsn_eapol_dst_supp(buf, len);
        if (supp < 0)
                return -1;

        tmp = os_malloc(len);
        if (tmp == NULL)
                return -1;
        os_memcpy(tmp, buf, len);
        if (supp) {
                wpa_printf(MSG_DEBUG, "RSN: IBSS RX EAPOL for Supplicant");
                wpa_sm_rx_eapol(peer->supp, peer->addr, tmp, len);
        } else {
                wpa_printf(MSG_DEBUG, "RSN: IBSS RX EAPOL for Authenticator");
                wpa_receive(ibss_rsn->auth_group, peer->auth, tmp, len);
        }
        os_free(tmp);

        return 1;
}


int ibss_rsn_rx_eapol(struct ibss_rsn *ibss_rsn, const u8 *src_addr,
                      const u8 *buf, size_t len)
{
        struct ibss_rsn_peer *peer;

        for (peer = ibss_rsn->peers; peer; peer = peer->next) {
                if (os_memcmp(src_addr, peer->addr, ETH_ALEN) == 0)
                        return ibss_rsn_process_rx_eapol(ibss_rsn, peer,
                                                         buf, len);
        }

        if (ibss_rsn_eapol_dst_supp(buf, len) > 0) {
                /*
                 * Create new IBSS peer based on an EAPOL message from the peer
                 * Authenticator.
                 */
                if (ibss_rsn_start(ibss_rsn, src_addr) < 0)
                        return -1;
                return ibss_rsn_process_rx_eapol(ibss_rsn, ibss_rsn->peers,
                                                 buf, len);
        }

        return 0;
}


void ibss_rsn_set_psk(struct ibss_rsn *ibss_rsn, const u8 *psk)
{
        os_memcpy(ibss_rsn->psk, psk, PMK_LEN);
}