eap_fast.c

Go to the documentation of this file.

#include "includes.h"

#include "common.h"
#include "aes_wrap.h"
#include "sha1.h"
#include "eap_i.h"
#include "eap_tls_common.h"
#include "tls.h"
#include "eap_common/eap_tlv_common.h"
#include "eap_common/eap_fast_common.h"


static void eap_fast_reset(struct eap_sm *sm, void *priv);


/* Private PAC-Opaque TLV types */
#define PAC_OPAQUE_TYPE_PAD 0
#define PAC_OPAQUE_TYPE_KEY 1
#define PAC_OPAQUE_TYPE_LIFETIME 2
#define PAC_OPAQUE_TYPE_IDENTITY 3

struct eap_fast_data {
        struct eap_ssl_data ssl;
        enum {
                START, PHASE1, PHASE2_START, PHASE2_ID, PHASE2_METHOD,
                CRYPTO_BINDING, REQUEST_PAC, SUCCESS, FAILURE
        } state;

        int fast_version;
        const struct eap_method *phase2_method;
        void *phase2_priv;
        int force_version;
        int peer_version;

        u8 crypto_binding_nonce[32];
        int final_result;

        struct eap_fast_key_block_provisioning *key_block_p;

        u8 simck[EAP_FAST_SIMCK_LEN];
        u8 cmk[EAP_FAST_CMK_LEN];
        int simck_idx;

        u8 pac_opaque_encr[16];
        u8 *srv_id;
        size_t srv_id_len;
        char *srv_id_info;

        int anon_provisioning;
        int send_new_pac; /* server triggered re-keying of Tunnel PAC */
        struct wpabuf *pending_phase2_resp;
        u8 *identity; /* from PAC-Opaque */
        size_t identity_len;
        int eap_seq;
        int tnc_started;

        int pac_key_lifetime;
        int pac_key_refresh_time;
};


static const char * eap_fast_state_txt(int state)
{
        switch (state) {
        case START:
                return "START";
        case PHASE1:
                return "PHASE1";
        case PHASE2_START:
                return "PHASE2_START";
        case PHASE2_ID:
                return "PHASE2_ID";
        case PHASE2_METHOD:
                return "PHASE2_METHOD";
        case CRYPTO_BINDING:
                return "CRYPTO_BINDING";
        case REQUEST_PAC:
                return "REQUEST_PAC";
        case SUCCESS:
                return "SUCCESS";
        case FAILURE:
                return "FAILURE";
        default:
                return "Unknown?!";
        }
}


static void eap_fast_state(struct eap_fast_data *data, int state)
{
        wpa_printf(MSG_DEBUG, "EAP-FAST: %s -> %s",
                   eap_fast_state_txt(data->state),
                   eap_fast_state_txt(state));
        data->state = state;
}


static EapType eap_fast_req_failure(struct eap_sm *sm,
                                    struct eap_fast_data *data)
{
        /* TODO: send Result TLV(FAILURE) */
        eap_fast_state(data, FAILURE);
        return EAP_TYPE_NONE;
}


static int eap_fast_session_ticket_cb(void *ctx, const u8 *ticket, size_t len,
                                      const u8 *client_random,
                                      const u8 *server_random,
                                      u8 *master_secret)
{
        struct eap_fast_data *data = ctx;
        const u8 *pac_opaque;
        size_t pac_opaque_len;
        u8 *buf, *pos, *end, *pac_key = NULL;
        os_time_t lifetime = 0;
        struct os_time now;
        u8 *identity = NULL;
        size_t identity_len = 0;

        wpa_printf(MSG_DEBUG, "EAP-FAST: SessionTicket callback");
        wpa_hexdump(MSG_DEBUG, "EAP-FAST: SessionTicket (PAC-Opaque)",
                    ticket, len);

        if (len < 4 || WPA_GET_BE16(ticket) != PAC_TYPE_PAC_OPAQUE) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Ignore invalid "
                           "SessionTicket");
                return 0;
        }

        pac_opaque_len = WPA_GET_BE16(ticket + 2);
        pac_opaque = ticket + 4;
        if (pac_opaque_len < 8 || pac_opaque_len % 8 ||
            pac_opaque_len > len - 4) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Ignore invalid PAC-Opaque "
                           "(len=%lu left=%lu)",
                           (unsigned long) pac_opaque_len,
                           (unsigned long) len);
                return 0;
        }
        wpa_hexdump(MSG_DEBUG, "EAP-FAST: Received PAC-Opaque",
                    pac_opaque, pac_opaque_len);

        buf = os_malloc(pac_opaque_len - 8);
        if (buf == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to allocate memory "
                           "for decrypting PAC-Opaque");
                return 0;
        }

        if (aes_unwrap(data->pac_opaque_encr, (pac_opaque_len - 8) / 8,
                       pac_opaque, buf) < 0) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to decrypt "
                           "PAC-Opaque");
                os_free(buf);
                /*
                 * This may have been caused by server changing the PAC-Opaque
                 * encryption key, so just ignore this PAC-Opaque instead of
                 * failing the authentication completely. Provisioning can now
                 * be used to provision a new PAC.
                 */
                return 0;
        }

        end = buf + pac_opaque_len - 8;
        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Decrypted PAC-Opaque",
                        buf, end - buf);

        pos = buf;
        while (pos + 1 < end) {
                if (pos + 2 + pos[1] > end)
                        break;

                switch (*pos) {
                case PAC_OPAQUE_TYPE_PAD:
                        pos = end;
                        break;
                case PAC_OPAQUE_TYPE_KEY:
                        if (pos[1] != EAP_FAST_PAC_KEY_LEN) {
                                wpa_printf(MSG_DEBUG, "EAP-FAST: Invalid "
                                           "PAC-Key length %d", pos[1]);
                                os_free(buf);
                                return -1;
                        }
                        pac_key = pos + 2;
                        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: PAC-Key from "
                                        "decrypted PAC-Opaque",
                                        pac_key, EAP_FAST_PAC_KEY_LEN);
                        break;
                case PAC_OPAQUE_TYPE_LIFETIME:
                        if (pos[1] != 4) {
                                wpa_printf(MSG_DEBUG, "EAP-FAST: Invalid "
                                           "PAC-Key lifetime length %d",
                                           pos[1]);
                                os_free(buf);
                                return -1;
                        }
                        lifetime = WPA_GET_BE32(pos + 2);
                        break;
                case PAC_OPAQUE_TYPE_IDENTITY:
                        identity = pos + 2;
                        identity_len = pos[1];
                        break;
                }

                pos += 2 + pos[1];
        }

        if (pac_key == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: No PAC-Key included in "
                           "PAC-Opaque");
                os_free(buf);
                return -1;
        }

        if (identity) {
                wpa_hexdump_ascii(MSG_DEBUG, "EAP-FAST: Identity from "
                                  "PAC-Opaque", identity, identity_len);
                os_free(data->identity);
                data->identity = os_malloc(identity_len);
                if (data->identity) {
                        os_memcpy(data->identity, identity, identity_len);
                        data->identity_len = identity_len;
                }
        }

        if (os_get_time(&now) < 0 || lifetime <= 0 || now.sec > lifetime) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC-Key not valid anymore "
                           "(lifetime=%ld now=%ld)", lifetime, now.sec);
                data->send_new_pac = 2;
                /*
                 * Allow PAC to be used to allow a PAC update with some level
                 * of server authentication (i.e., do not fall back to full TLS
                 * handshake since we cannot be sure that the peer would be
                 * able to validate server certificate now). However, reject
                 * the authentication since the PAC was not valid anymore. Peer
                 * can connect again with the newly provisioned PAC after this.
                 */
        } else if (lifetime - now.sec < data->pac_key_refresh_time) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC-Key soft timeout; send "
                           "an update if authentication succeeds");
                data->send_new_pac = 1;
        }

        eap_fast_derive_master_secret(pac_key, server_random, client_random,
                                      master_secret);

        os_free(buf);

        return 1;
}


static void eap_fast_derive_key_auth(struct eap_sm *sm,
                                     struct eap_fast_data *data)
{
        u8 *sks;

        /* RFC 4851, Section 5.1:
         * Extra key material after TLS key_block: session_key_seed[40]
         */

        sks = eap_fast_derive_key(sm->ssl_ctx, data->ssl.conn, "key expansion",
                                  EAP_FAST_SKS_LEN);
        if (sks == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to derive "
                           "session_key_seed");
                return;
        }

        /*
         * RFC 4851, Section 5.2:
         * S-IMCK[0] = session_key_seed
         */
        wpa_hexdump_key(MSG_DEBUG,
                        "EAP-FAST: session_key_seed (SKS = S-IMCK[0])",
                        sks, EAP_FAST_SKS_LEN);
        data->simck_idx = 0;
        os_memcpy(data->simck, sks, EAP_FAST_SIMCK_LEN);
        os_free(sks);
}


static void eap_fast_derive_key_provisioning(struct eap_sm *sm,
                                             struct eap_fast_data *data)
{
        os_free(data->key_block_p);
        data->key_block_p = (struct eap_fast_key_block_provisioning *)
                eap_fast_derive_key(sm->ssl_ctx, data->ssl.conn,
                                    "key expansion",
                                    sizeof(*data->key_block_p));
        if (data->key_block_p == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to derive key block");
                return;
        }
        /*
         * RFC 4851, Section 5.2:
         * S-IMCK[0] = session_key_seed
         */
        wpa_hexdump_key(MSG_DEBUG,
                        "EAP-FAST: session_key_seed (SKS = S-IMCK[0])",
                        data->key_block_p->session_key_seed,
                        sizeof(data->key_block_p->session_key_seed));
        data->simck_idx = 0;
        os_memcpy(data->simck, data->key_block_p->session_key_seed,
                  EAP_FAST_SIMCK_LEN);
        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: server_challenge",
                        data->key_block_p->server_challenge,
                        sizeof(data->key_block_p->server_challenge));
        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: client_challenge",
                        data->key_block_p->client_challenge,
                        sizeof(data->key_block_p->client_challenge));
}


static int eap_fast_get_phase2_key(struct eap_sm *sm,
                                   struct eap_fast_data *data,
                                   u8 *isk, size_t isk_len)
{
        u8 *key;
        size_t key_len;

        os_memset(isk, 0, isk_len);

        if (data->phase2_method == NULL || data->phase2_priv == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Phase 2 method not "
                           "available");
                return -1;
        }

        if (data->phase2_method->getKey == NULL)
                return 0;

        if ((key = data->phase2_method->getKey(sm, data->phase2_priv,
                                               &key_len)) == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Could not get key material "
                           "from Phase 2");
                return -1;
        }

        if (key_len > isk_len)
                key_len = isk_len;
        if (key_len == 32 &&
            data->phase2_method->vendor == EAP_VENDOR_IETF &&
            data->phase2_method->method == EAP_TYPE_MSCHAPV2) {
                /*
                 * EAP-FAST uses reverse order for MS-MPPE keys when deriving
                 * MSK from EAP-MSCHAPv2. Swap the keys here to get the correct
                 * ISK for EAP-FAST cryptobinding.
                 */
                os_memcpy(isk, key + 16, 16);
                os_memcpy(isk + 16, key, 16);
        } else
                os_memcpy(isk, key, key_len);
        os_free(key);

        return 0;
}


static int eap_fast_update_icmk(struct eap_sm *sm, struct eap_fast_data *data)
{
        u8 isk[32], imck[60];

        wpa_printf(MSG_DEBUG, "EAP-FAST: Deriving ICMK[%d] (S-IMCK and CMK)",
                   data->simck_idx + 1);

        /*
         * RFC 4851, Section 5.2:
         * IMCK[j] = T-PRF(S-IMCK[j-1], "Inner Methods Compound Keys",
         *                 MSK[j], 60)
         * S-IMCK[j] = first 40 octets of IMCK[j]
         * CMK[j] = last 20 octets of IMCK[j]
         */

        if (eap_fast_get_phase2_key(sm, data, isk, sizeof(isk)) < 0)
                return -1;
        wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: ISK[j]", isk, sizeof(isk));
        sha1_t_prf(data->simck, EAP_FAST_SIMCK_LEN,
                   "Inner Methods Compound Keys",
                   isk, sizeof(isk), imck, sizeof(imck));
        data->simck_idx++;
        os_memcpy(data->simck, imck, EAP_FAST_SIMCK_LEN);
        wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: S-IMCK[j]",
                        data->simck, EAP_FAST_SIMCK_LEN);
        os_memcpy(data->cmk, imck + EAP_FAST_SIMCK_LEN, EAP_FAST_CMK_LEN);
        wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: CMK[j]",
                        data->cmk, EAP_FAST_CMK_LEN);

        return 0;
}


static void * eap_fast_init(struct eap_sm *sm)
{
        struct eap_fast_data *data;
        u8 ciphers[5] = {
                TLS_CIPHER_ANON_DH_AES128_SHA,
                TLS_CIPHER_AES128_SHA,
                TLS_CIPHER_RSA_DHE_AES128_SHA,
                TLS_CIPHER_RC4_SHA,
                TLS_CIPHER_NONE
        };

        data = os_zalloc(sizeof(*data));
        if (data == NULL)
                return NULL;
        data->fast_version = EAP_FAST_VERSION;
        data->force_version = -1;
        if (sm->user && sm->user->force_version >= 0) {
                data->force_version = sm->user->force_version;
                wpa_printf(MSG_DEBUG, "EAP-FAST: forcing version %d",
                           data->force_version);
                data->fast_version = data->force_version;
        }
        data->state = START;

        if (eap_server_tls_ssl_init(sm, &data->ssl, 0)) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to initialize SSL.");
                eap_fast_reset(sm, data);
                return NULL;
        }

        if (tls_connection_set_cipher_list(sm->ssl_ctx, data->ssl.conn,
                                           ciphers) < 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to set TLS cipher "
                           "suites");
                eap_fast_reset(sm, data);
                return NULL;
        }

        if (tls_connection_set_session_ticket_cb(sm->ssl_ctx, data->ssl.conn,
                                                 eap_fast_session_ticket_cb,
                                                 data) < 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to set SessionTicket "
                           "callback");
                eap_fast_reset(sm, data);
                return NULL;
        }

        if (sm->pac_opaque_encr_key == NULL) {
                wpa_printf(MSG_INFO, "EAP-FAST: No PAC-Opaque encryption key "
                           "configured");
                eap_fast_reset(sm, data);
                return NULL;
        }
        os_memcpy(data->pac_opaque_encr, sm->pac_opaque_encr_key,
                  sizeof(data->pac_opaque_encr));

        if (sm->eap_fast_a_id == NULL) {
                wpa_printf(MSG_INFO, "EAP-FAST: No A-ID configured");
                eap_fast_reset(sm, data);
                return NULL;
        }
        data->srv_id = os_malloc(sm->eap_fast_a_id_len);
        if (data->srv_id == NULL) {
                eap_fast_reset(sm, data);
                return NULL;
        }
        os_memcpy(data->srv_id, sm->eap_fast_a_id, sm->eap_fast_a_id_len);
        data->srv_id_len = sm->eap_fast_a_id_len;

        if (sm->eap_fast_a_id_info == NULL) {
                wpa_printf(MSG_INFO, "EAP-FAST: No A-ID-Info configured");
                eap_fast_reset(sm, data);
                return NULL;
        }
        data->srv_id_info = os_strdup(sm->eap_fast_a_id_info);
        if (data->srv_id_info == NULL) {
                eap_fast_reset(sm, data);
                return NULL;
        }

        /* PAC-Key lifetime in seconds (hard limit) */
        data->pac_key_lifetime = sm->pac_key_lifetime;

        /*
         * PAC-Key refresh time in seconds (soft limit on remaining hard
         * limit). The server will generate a new PAC-Key when this number of
         * seconds (or fewer) of the lifetime remains.
         */
        data->pac_key_refresh_time = sm->pac_key_refresh_time;

        return data;
}


static void eap_fast_reset(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        if (data == NULL)
                return;
        if (data->phase2_priv && data->phase2_method)
                data->phase2_method->reset(sm, data->phase2_priv);
        eap_server_tls_ssl_deinit(sm, &data->ssl);
        os_free(data->srv_id);
        os_free(data->srv_id_info);
        os_free(data->key_block_p);
        wpabuf_free(data->pending_phase2_resp);
        os_free(data->identity);
        os_free(data);
}


static struct wpabuf * eap_fast_build_start(struct eap_sm *sm,
                                            struct eap_fast_data *data, u8 id)
{
        struct wpabuf *req;

        req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_FAST,
                            1 + sizeof(struct pac_tlv_hdr) + data->srv_id_len,
                            EAP_CODE_REQUEST, id);
        if (req == NULL) {
                wpa_printf(MSG_ERROR, "EAP-FAST: Failed to allocate memory for"
                           " request");
                eap_fast_state(data, FAILURE);
                return NULL;
        }

        wpabuf_put_u8(req, EAP_TLS_FLAGS_START | data->fast_version);

        /* RFC 4851, 4.1.1. Authority ID Data */
        eap_fast_put_tlv(req, PAC_TYPE_A_ID, data->srv_id, data->srv_id_len);

        eap_fast_state(data, PHASE1);

        return req;
}


static int eap_fast_phase1_done(struct eap_sm *sm, struct eap_fast_data *data)
{
        char cipher[64];

        wpa_printf(MSG_DEBUG, "EAP-FAST: Phase1 done, starting Phase2");

        if (tls_get_cipher(sm->ssl_ctx, data->ssl.conn, cipher, sizeof(cipher))
            < 0) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to get cipher "
                           "information");
                eap_fast_state(data, FAILURE);
                return -1;
        }
        data->anon_provisioning = os_strstr(cipher, "ADH") != NULL;
                    
        if (data->anon_provisioning) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Anonymous provisioning");
                eap_fast_derive_key_provisioning(sm, data);
        } else
                eap_fast_derive_key_auth(sm, data);

        eap_fast_state(data, PHASE2_START);

        return 0;
}


static struct wpabuf * eap_fast_build_phase2_req(struct eap_sm *sm,
                                                 struct eap_fast_data *data,
                                                 u8 id)
{
        struct wpabuf *req;

        if (data->phase2_priv == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Phase 2 method not "
                           "initialized");
                return NULL;
        }
        req = data->phase2_method->buildReq(sm, data->phase2_priv, id);
        if (req == NULL)
                return NULL;

        wpa_hexdump_buf_key(MSG_MSGDUMP, "EAP-FAST: Phase 2 EAP-Request", req);
        return eap_fast_tlv_eap_payload(req);
}


static struct wpabuf * eap_fast_build_crypto_binding(
        struct eap_sm *sm, struct eap_fast_data *data)
{
        struct wpabuf *buf;
        struct eap_tlv_result_tlv *result;
        struct eap_tlv_crypto_binding_tlv *binding;

        buf = wpabuf_alloc(2 * sizeof(*result) + sizeof(*binding));
        if (buf == NULL)
                return NULL;

        if (data->send_new_pac || data->anon_provisioning ||
            data->phase2_method)
                data->final_result = 0;
        else
                data->final_result = 1;

        if (!data->final_result || data->eap_seq > 1) {
                /* Intermediate-Result */
                wpa_printf(MSG_DEBUG, "EAP-FAST: Add Intermediate-Result TLV "
                           "(status=SUCCESS)");
                result = wpabuf_put(buf, sizeof(*result));
                result->tlv_type = host_to_be16(
                        EAP_TLV_TYPE_MANDATORY |
                        EAP_TLV_INTERMEDIATE_RESULT_TLV);
                result->length = host_to_be16(2);
                result->status = host_to_be16(EAP_TLV_RESULT_SUCCESS);
        }

        if (data->final_result) {
                /* Result TLV */
                wpa_printf(MSG_DEBUG, "EAP-FAST: Add Result TLV "
                           "(status=SUCCESS)");
                result = wpabuf_put(buf, sizeof(*result));
                result->tlv_type = host_to_be16(EAP_TLV_TYPE_MANDATORY |
                                                EAP_TLV_RESULT_TLV);
                result->length = host_to_be16(2);
                result->status = host_to_be16(EAP_TLV_RESULT_SUCCESS);
        }

        /* Crypto-Binding TLV */
        binding = wpabuf_put(buf, sizeof(*binding));
        binding->tlv_type = host_to_be16(EAP_TLV_TYPE_MANDATORY |
                                         EAP_TLV_CRYPTO_BINDING_TLV);
        binding->length = host_to_be16(sizeof(*binding) -
                                       sizeof(struct eap_tlv_hdr));
        binding->version = EAP_FAST_VERSION;
        binding->received_version = data->peer_version;
        binding->subtype = EAP_TLV_CRYPTO_BINDING_SUBTYPE_REQUEST;
        if (os_get_random(binding->nonce, sizeof(binding->nonce)) < 0) {
                wpabuf_free(buf);
                return NULL;
        }

        /*
         * RFC 4851, Section 4.2.8:
         * The nonce in a request MUST have its least significant bit set to 0.
         */
        binding->nonce[sizeof(binding->nonce) - 1] &= ~0x01;

        os_memcpy(data->crypto_binding_nonce, binding->nonce,
                  sizeof(binding->nonce));

        /*
         * RFC 4851, Section 5.3:
         * CMK = CMK[j]
         * Compound-MAC = HMAC-SHA1( CMK, Crypto-Binding TLV )
         */

        hmac_sha1(data->cmk, EAP_FAST_CMK_LEN,
                  (u8 *) binding, sizeof(*binding),
                  binding->compound_mac);

        wpa_printf(MSG_DEBUG, "EAP-FAST: Add Crypto-Binding TLV: Version %d "
                   "Received Version %d SubType %d",
                   binding->version, binding->received_version,
                   binding->subtype);
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: NONCE",
                    binding->nonce, sizeof(binding->nonce));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Compound MAC",
                    binding->compound_mac, sizeof(binding->compound_mac));

        return buf;
}


static struct wpabuf * eap_fast_build_pac(struct eap_sm *sm,
                                          struct eap_fast_data *data)
{
        u8 pac_key[EAP_FAST_PAC_KEY_LEN];
        u8 *pac_buf, *pac_opaque;
        struct wpabuf *buf;
        u8 *pos;
        size_t buf_len, srv_id_info_len, pac_len;
        struct eap_tlv_hdr *pac_tlv;
        struct pac_tlv_hdr *pac_info;
        struct eap_tlv_result_tlv *result;
        struct os_time now;

        if (os_get_random(pac_key, EAP_FAST_PAC_KEY_LEN) < 0 ||
            os_get_time(&now) < 0)
                return NULL;
        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Generated PAC-Key",
                        pac_key, EAP_FAST_PAC_KEY_LEN);

        pac_len = (2 + EAP_FAST_PAC_KEY_LEN) + (2 + 4) +
                (2 + sm->identity_len) + 8;
        pac_buf = os_malloc(pac_len);
        if (pac_buf == NULL)
                return NULL;

        srv_id_info_len = os_strlen(data->srv_id_info);

        pos = pac_buf;
        *pos++ = PAC_OPAQUE_TYPE_KEY;
        *pos++ = EAP_FAST_PAC_KEY_LEN;
        os_memcpy(pos, pac_key, EAP_FAST_PAC_KEY_LEN);
        pos += EAP_FAST_PAC_KEY_LEN;

        *pos++ = PAC_OPAQUE_TYPE_LIFETIME;
        *pos++ = 4;
        WPA_PUT_BE32(pos, now.sec + data->pac_key_lifetime);
        pos += 4;

        if (sm->identity) {
                *pos++ = PAC_OPAQUE_TYPE_IDENTITY;
                *pos++ = sm->identity_len;
                os_memcpy(pos, sm->identity, sm->identity_len);
                pos += sm->identity_len;
        }

        pac_len = pos - pac_buf;
        while (pac_len % 8) {
                *pos++ = PAC_OPAQUE_TYPE_PAD;
                pac_len++;
        }

        pac_opaque = os_malloc(pac_len + 8);
        if (pac_opaque == NULL) {
                os_free(pac_buf);
                return NULL;
        }
        if (aes_wrap(data->pac_opaque_encr, pac_len / 8, pac_buf,
                     pac_opaque) < 0) {
                os_free(pac_buf);
                os_free(pac_opaque);
                return NULL;
        }
        os_free(pac_buf);

        pac_len += 8;
        wpa_hexdump(MSG_DEBUG, "EAP-FAST: PAC-Opaque",
                    pac_opaque, pac_len);

        buf_len = sizeof(*pac_tlv) +
                sizeof(struct pac_tlv_hdr) + EAP_FAST_PAC_KEY_LEN +
                sizeof(struct pac_tlv_hdr) + pac_len +
                data->srv_id_len + srv_id_info_len + 100 + sizeof(*result);
        buf = wpabuf_alloc(buf_len);
        if (buf == NULL) {
                os_free(pac_opaque);
                return NULL;
        }

        /* Result TLV */
        wpa_printf(MSG_DEBUG, "EAP-FAST: Add Result TLV (status=SUCCESS)");
        result = wpabuf_put(buf, sizeof(*result));
        WPA_PUT_BE16((u8 *) &result->tlv_type,
                     EAP_TLV_TYPE_MANDATORY | EAP_TLV_RESULT_TLV);
        WPA_PUT_BE16((u8 *) &result->length, 2);
        WPA_PUT_BE16((u8 *) &result->status, EAP_TLV_RESULT_SUCCESS);

        /* PAC TLV */
        wpa_printf(MSG_DEBUG, "EAP-FAST: Add PAC TLV");
        pac_tlv = wpabuf_put(buf, sizeof(*pac_tlv));
        pac_tlv->tlv_type = host_to_be16(EAP_TLV_TYPE_MANDATORY |
                                         EAP_TLV_PAC_TLV);

        /* PAC-Key */
        eap_fast_put_tlv(buf, PAC_TYPE_PAC_KEY, pac_key, EAP_FAST_PAC_KEY_LEN);

        /* PAC-Opaque */
        eap_fast_put_tlv(buf, PAC_TYPE_PAC_OPAQUE, pac_opaque, pac_len);
        os_free(pac_opaque);

        /* PAC-Info */
        pac_info = wpabuf_put(buf, sizeof(*pac_info));
        pac_info->type = host_to_be16(PAC_TYPE_PAC_INFO);

        /* PAC-Lifetime (inside PAC-Info) */
        eap_fast_put_tlv_hdr(buf, PAC_TYPE_CRED_LIFETIME, 4);
        wpabuf_put_be32(buf, now.sec + data->pac_key_lifetime);

        /* A-ID (inside PAC-Info) */
        eap_fast_put_tlv(buf, PAC_TYPE_A_ID, data->srv_id, data->srv_id_len);
        
        /* Note: headers may be misaligned after A-ID */

        /* A-ID-Info (inside PAC-Info) */
        eap_fast_put_tlv(buf, PAC_TYPE_A_ID_INFO, data->srv_id_info,
                         srv_id_info_len);

        /* PAC-Type (inside PAC-Info) */
        eap_fast_put_tlv_hdr(buf, PAC_TYPE_PAC_TYPE, 2);
        wpabuf_put_be16(buf, PAC_TYPE_TUNNEL_PAC);

        /* Update PAC-Info and PAC TLV Length fields */
        pos = wpabuf_put(buf, 0);
        pac_info->len = host_to_be16(pos - (u8 *) (pac_info + 1));
        pac_tlv->length = host_to_be16(pos - (u8 *) (pac_tlv + 1));

        return buf;
}


static struct wpabuf * eap_fast_buildReq(struct eap_sm *sm, void *priv, u8 id)
{
        struct eap_fast_data *data = priv;
        struct wpabuf *req = NULL;
        struct wpabuf *encr;

        if (data->ssl.state == FRAG_ACK) {
                return eap_server_tls_build_ack(id, EAP_TYPE_FAST,
                                                data->fast_version);
        }

        if (data->ssl.state == WAIT_FRAG_ACK) {
                return eap_server_tls_build_msg(&data->ssl, EAP_TYPE_FAST,
                                                data->fast_version, id);
        }

        switch (data->state) {
        case START:
                return eap_fast_build_start(sm, data, id);
        case PHASE1:
                if (tls_connection_established(sm->ssl_ctx, data->ssl.conn)) {
                        if (eap_fast_phase1_done(sm, data) < 0)
                                return NULL;
                }
                break;
        case PHASE2_ID:
        case PHASE2_METHOD:
                req = eap_fast_build_phase2_req(sm, data, id);
                break;
        case CRYPTO_BINDING:
                req = eap_fast_build_crypto_binding(sm, data);
                if (data->phase2_method) {
                        /*
                         * Include the start of the next EAP method in the
                         * sequence in the same message with Crypto-Binding to
                         * save a round-trip.
                         */
                        struct wpabuf *eap;
                        eap = eap_fast_build_phase2_req(sm, data, id);
                        req = wpabuf_concat(req, eap);
                        eap_fast_state(data, PHASE2_METHOD);
                }
                break;
        case REQUEST_PAC:
                req = eap_fast_build_pac(sm, data);
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-FAST: %s - unexpected state %d",
                           __func__, data->state);
                return NULL;
        }

        if (req) {
                wpa_hexdump_buf_key(MSG_DEBUG, "EAP-FAST: Encrypting Phase 2 "
                                    "TLVs", req);
                encr = eap_server_tls_encrypt(sm, &data->ssl,
                                              wpabuf_mhead(req),
                                              wpabuf_len(req));
                wpabuf_free(req);

                wpabuf_free(data->ssl.out_buf);
                data->ssl.out_used = 0;
                data->ssl.out_buf = encr;
        }

        return eap_server_tls_build_msg(&data->ssl, EAP_TYPE_FAST,
                                        data->fast_version, id);
}


static Boolean eap_fast_check(struct eap_sm *sm, void *priv,
                              struct wpabuf *respData)
{
        const u8 *pos;
        size_t len;

        pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_FAST, respData, &len);
        if (pos == NULL || len < 1) {
                wpa_printf(MSG_INFO, "EAP-FAST: Invalid frame");
                return TRUE;
        }

        return FALSE;
}


static int eap_fast_phase2_init(struct eap_sm *sm, struct eap_fast_data *data,
                                EapType eap_type)
{
        if (data->phase2_priv && data->phase2_method) {
                data->phase2_method->reset(sm, data->phase2_priv);
                data->phase2_method = NULL;
                data->phase2_priv = NULL;
        }
        data->phase2_method = eap_server_get_eap_method(EAP_VENDOR_IETF,
                                                        eap_type);
        if (!data->phase2_method)
                return -1;

        if (data->key_block_p) {
                sm->auth_challenge = data->key_block_p->server_challenge;
                sm->peer_challenge = data->key_block_p->client_challenge;
        }
        sm->init_phase2 = 1;
        data->phase2_priv = data->phase2_method->init(sm);
        sm->init_phase2 = 0;
        sm->auth_challenge = NULL;
        sm->peer_challenge = NULL;

        return data->phase2_priv == NULL ? -1 : 0;
}


static void eap_fast_process_phase2_response(struct eap_sm *sm,
                                             struct eap_fast_data *data,
                                             u8 *in_data, size_t in_len)
{
        u8 next_type = EAP_TYPE_NONE;
        struct eap_hdr *hdr;
        u8 *pos;
        size_t left;
        struct wpabuf buf;
        const struct eap_method *m = data->phase2_method;
        void *priv = data->phase2_priv;

        if (priv == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: %s - Phase2 not "
                           "initialized?!", __func__);
                return;
        }

        hdr = (struct eap_hdr *) in_data;
        pos = (u8 *) (hdr + 1);

        if (in_len > sizeof(*hdr) && *pos == EAP_TYPE_NAK) {
                left = in_len - sizeof(*hdr);
                wpa_hexdump(MSG_DEBUG, "EAP-FAST: Phase2 type Nak'ed; "
                            "allowed types", pos + 1, left - 1);
#ifdef EAP_SERVER_TNC
                if (m && m->vendor == EAP_VENDOR_IETF &&
                    m->method == EAP_TYPE_TNC) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Peer Nak'ed required "
                                   "TNC negotiation");
                        next_type = eap_fast_req_failure(sm, data);
                        eap_fast_phase2_init(sm, data, next_type);
                        return;
                }
#endif /* EAP_SERVER_TNC */
                eap_sm_process_nak(sm, pos + 1, left - 1);
                if (sm->user && sm->user_eap_method_index < EAP_MAX_METHODS &&
                    sm->user->methods[sm->user_eap_method_index].method !=
                    EAP_TYPE_NONE) {
                        next_type = sm->user->methods[
                                sm->user_eap_method_index++].method;
                        wpa_printf(MSG_DEBUG, "EAP-FAST: try EAP type %d",
                                   next_type);
                } else {
                        next_type = eap_fast_req_failure(sm, data);
                }
                eap_fast_phase2_init(sm, data, next_type);
                return;
        }

        wpabuf_set(&buf, in_data, in_len);

        if (m->check(sm, priv, &buf)) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Phase2 check() asked to "
                           "ignore the packet");
                next_type = eap_fast_req_failure(sm, data);
                return;
        }

        m->process(sm, priv, &buf);

        if (!m->isDone(sm, priv))
                return;

        if (!m->isSuccess(sm, priv)) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Phase2 method failed");
                next_type = eap_fast_req_failure(sm, data);
                eap_fast_phase2_init(sm, data, next_type);
                return;
        }

        switch (data->state) {
        case PHASE2_ID:
                if (eap_user_get(sm, sm->identity, sm->identity_len, 1) != 0) {
                        wpa_hexdump_ascii(MSG_DEBUG, "EAP-FAST: Phase2 "
                                          "Identity not found in the user "
                                          "database",
                                          sm->identity, sm->identity_len);
                        next_type = eap_fast_req_failure(sm, data);
                        break;
                }

                eap_fast_state(data, PHASE2_METHOD);
                if (data->anon_provisioning) {
                        /*
                         * Only EAP-MSCHAPv2 is allowed for anonymous
                         * provisioning.
                         */
                        next_type = EAP_TYPE_MSCHAPV2;
                        sm->user_eap_method_index = 0;
                } else {
                        next_type = sm->user->methods[0].method;
                        sm->user_eap_method_index = 1;
                }
                wpa_printf(MSG_DEBUG, "EAP-FAST: try EAP type %d", next_type);
                break;
        case PHASE2_METHOD:
        case CRYPTO_BINDING:
                eap_fast_update_icmk(sm, data);
                eap_fast_state(data, CRYPTO_BINDING);
                data->eap_seq++;
                next_type = EAP_TYPE_NONE;
#ifdef EAP_SERVER_TNC
                if (sm->tnc && !data->tnc_started) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Initialize TNC");
                        next_type = EAP_TYPE_TNC;
                        data->tnc_started = 1;
                }
#endif /* EAP_SERVER_TNC */
                break;
        case FAILURE:
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-FAST: %s - unexpected state %d",
                           __func__, data->state);
                break;
        }

        eap_fast_phase2_init(sm, data, next_type);
}


static void eap_fast_process_phase2_eap(struct eap_sm *sm,
                                        struct eap_fast_data *data,
                                        u8 *in_data, size_t in_len)
{
        struct eap_hdr *hdr;
        size_t len;

        hdr = (struct eap_hdr *) in_data;
        if (in_len < (int) sizeof(*hdr)) {
                wpa_printf(MSG_INFO, "EAP-FAST: Too short Phase 2 "
                           "EAP frame (len=%lu)", (unsigned long) in_len);
                eap_fast_req_failure(sm, data);
                return;
        }
        len = be_to_host16(hdr->length);
        if (len > in_len) {
                wpa_printf(MSG_INFO, "EAP-FAST: Length mismatch in "
                           "Phase 2 EAP frame (len=%lu hdr->length=%lu)",
                           (unsigned long) in_len, (unsigned long) len);
                eap_fast_req_failure(sm, data);
                return;
        }
        wpa_printf(MSG_DEBUG, "EAP-FAST: Received Phase 2: code=%d "
                   "identifier=%d length=%lu", hdr->code, hdr->identifier,
                   (unsigned long) len);
        switch (hdr->code) {
        case EAP_CODE_RESPONSE:
                eap_fast_process_phase2_response(sm, data, (u8 *) hdr, len);
                break;
        default:
                wpa_printf(MSG_INFO, "EAP-FAST: Unexpected code=%d in "
                           "Phase 2 EAP header", hdr->code);
                break;
        }
}


static int eap_fast_parse_tlvs(u8 *data, size_t data_len,
                               struct eap_fast_tlv_parse *tlv)
{
        int mandatory, tlv_type, len, res;
        u8 *pos, *end;

        os_memset(tlv, 0, sizeof(*tlv));

        pos = data;
        end = data + data_len;
        while (pos + 4 < end) {
                mandatory = pos[0] & 0x80;
                tlv_type = WPA_GET_BE16(pos) & 0x3fff;
                pos += 2;
                len = WPA_GET_BE16(pos);
                pos += 2;
                if (pos + len > end) {
                        wpa_printf(MSG_INFO, "EAP-FAST: TLV overflow");
                        return -1;
                }
                wpa_printf(MSG_DEBUG, "EAP-FAST: Received Phase 2: "
                           "TLV type %d length %d%s",
                           tlv_type, len, mandatory ? " (mandatory)" : "");

                res = eap_fast_parse_tlv(tlv, tlv_type, pos, len);
                if (res == -2)
                        break;
                if (res < 0) {
                        if (mandatory) {
                                wpa_printf(MSG_DEBUG, "EAP-FAST: Nak unknown "
                                           "mandatory TLV type %d", tlv_type);
                                /* TODO: generate Nak TLV */
                                break;
                        } else {
                                wpa_printf(MSG_DEBUG, "EAP-FAST: Ignored "
                                           "unknown optional TLV type %d",
                                           tlv_type);
                        }
                }

                pos += len;
        }

        return 0;
}


static int eap_fast_validate_crypto_binding(
        struct eap_fast_data *data, struct eap_tlv_crypto_binding_tlv *b,
        size_t bind_len)
{
        u8 cmac[SHA1_MAC_LEN];

        wpa_printf(MSG_DEBUG, "EAP-FAST: Reply Crypto-Binding TLV: "
                   "Version %d Received Version %d SubType %d",
                   b->version, b->received_version, b->subtype);
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: NONCE",
                    b->nonce, sizeof(b->nonce));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Compound MAC",
                    b->compound_mac, sizeof(b->compound_mac));

        if (b->version != EAP_FAST_VERSION ||
            b->received_version != EAP_FAST_VERSION) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Unexpected version "
                           "in Crypto-Binding: version %d "
                           "received_version %d", b->version,
                           b->received_version);
                return -1;
        }

        if (b->subtype != EAP_TLV_CRYPTO_BINDING_SUBTYPE_RESPONSE) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Unexpected subtype in "
                           "Crypto-Binding: %d", b->subtype);
                return -1;
        }

        if (os_memcmp(data->crypto_binding_nonce, b->nonce, 31) != 0 ||
            (data->crypto_binding_nonce[31] | 1) != b->nonce[31]) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Invalid nonce in "
                           "Crypto-Binding");
                return -1;
        }

        os_memcpy(cmac, b->compound_mac, sizeof(cmac));
        os_memset(b->compound_mac, 0, sizeof(cmac));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV for "
                    "Compound MAC calculation",
                    (u8 *) b, bind_len);
        hmac_sha1(data->cmk, EAP_FAST_CMK_LEN, (u8 *) b, bind_len,
                  b->compound_mac);
        if (os_memcmp(cmac, b->compound_mac, sizeof(cmac)) != 0) {
                wpa_hexdump(MSG_MSGDUMP,
                            "EAP-FAST: Calculated Compound MAC",
                            b->compound_mac, sizeof(cmac));
                wpa_printf(MSG_INFO, "EAP-FAST: Compound MAC did not "
                           "match");
                return -1;
        }

        return 0;
}


static int eap_fast_pac_type(u8 *pac, size_t len, u16 type)
{
        struct eap_tlv_pac_type_tlv *tlv;

        if (pac == NULL || len != sizeof(*tlv))
                return 0;

        tlv = (struct eap_tlv_pac_type_tlv *) pac;

        return be_to_host16(tlv->tlv_type) == PAC_TYPE_PAC_TYPE &&
                be_to_host16(tlv->length) == 2 &&
                be_to_host16(tlv->pac_type) == type;
}


static void eap_fast_process_phase2_tlvs(struct eap_sm *sm,
                                         struct eap_fast_data *data,
                                         u8 *in_data, size_t in_len)
{
        struct eap_fast_tlv_parse tlv;
        int check_crypto_binding = data->state == CRYPTO_BINDING;

        if (eap_fast_parse_tlvs(in_data, in_len, &tlv) < 0) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to parse received "
                           "Phase 2 TLVs");
                return;
        }

        if (tlv.result == EAP_TLV_RESULT_FAILURE) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Result TLV indicated "
                           "failure");
                eap_fast_state(data, FAILURE);
                return;
        }

        if (data->state == REQUEST_PAC) {
                u16 type, len, res;
                if (tlv.pac == NULL || tlv.pac_len < 6) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: No PAC "
                                   "Acknowledgement received");
                        eap_fast_state(data, FAILURE);
                        return;
                }

                type = WPA_GET_BE16(tlv.pac);
                len = WPA_GET_BE16(tlv.pac + 2);
                res = WPA_GET_BE16(tlv.pac + 4);

                if (type != PAC_TYPE_PAC_ACKNOWLEDGEMENT || len != 2 ||
                    res != EAP_TLV_RESULT_SUCCESS) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: PAC TLV did not "
                                   "contain acknowledgement");
                        eap_fast_state(data, FAILURE);
                        return;
                }

                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC-Acknowledgement received "
                           "- PAC provisioning succeeded");
                eap_fast_state(data, (data->anon_provisioning ||
                                      data->send_new_pac == 2) ?
                               FAILURE : SUCCESS);
                return;
        }

        if (check_crypto_binding) {
                if (tlv.crypto_binding == NULL) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: No Crypto-Binding "
                                   "TLV received");
                        eap_fast_state(data, FAILURE);
                        return;
                }

                if (data->final_result &&
                    tlv.result != EAP_TLV_RESULT_SUCCESS) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Crypto-Binding TLV "
                                   "without Success Result");
                        eap_fast_state(data, FAILURE);
                        return;
                }

                if (!data->final_result &&
                    tlv.iresult != EAP_TLV_RESULT_SUCCESS) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Crypto-Binding TLV "
                                   "without intermediate Success Result");
                        eap_fast_state(data, FAILURE);
                        return;
                }

                if (eap_fast_validate_crypto_binding(data, tlv.crypto_binding,
                                                     tlv.crypto_binding_len)) {
                        eap_fast_state(data, FAILURE);
                        return;
                }

                wpa_printf(MSG_DEBUG, "EAP-FAST: Valid Crypto-Binding TLV "
                           "received");
                if (data->final_result) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Authentication "
                                   "completed successfully");
                }

                if (data->anon_provisioning &&
                    sm->eap_fast_prov != ANON_PROV &&
                    sm->eap_fast_prov != BOTH_PROV) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Client is trying to "
                                   "use unauthenticated provisioning which is "
                                   "disabled");
                        eap_fast_state(data, FAILURE);
                        return;
                }

                if (sm->eap_fast_prov != AUTH_PROV &&
                    sm->eap_fast_prov != BOTH_PROV &&
                    tlv.request_action == EAP_TLV_ACTION_PROCESS_TLV &&
                    eap_fast_pac_type(tlv.pac, tlv.pac_len,
                                      PAC_TYPE_TUNNEL_PAC)) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Client is trying to "
                                   "use authenticated provisioning which is "
                                   "disabled");
                        eap_fast_state(data, FAILURE);
                        return;
                }

                if (data->anon_provisioning ||
                    (tlv.request_action == EAP_TLV_ACTION_PROCESS_TLV &&
                     eap_fast_pac_type(tlv.pac, tlv.pac_len,
                                       PAC_TYPE_TUNNEL_PAC))) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Requested a new "
                                   "Tunnel PAC");
                        eap_fast_state(data, REQUEST_PAC);
                } else if (data->send_new_pac) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Server triggered "
                                   "re-keying of Tunnel PAC");
                        eap_fast_state(data, REQUEST_PAC);
                } else if (data->final_result)
                        eap_fast_state(data, SUCCESS);
        }

        if (tlv.eap_payload_tlv) {
                eap_fast_process_phase2_eap(sm, data, tlv.eap_payload_tlv,
                                            tlv.eap_payload_tlv_len);
        }
}


static void eap_fast_process_phase2(struct eap_sm *sm,
                                    struct eap_fast_data *data,
                                    struct wpabuf *in_buf)
{
        u8 *in_decrypted;
        int len_decrypted;
        size_t buf_len;
        u8 *in_data;
        size_t in_len;

        in_data = wpabuf_mhead(in_buf);
        in_len = wpabuf_len(in_buf);

        wpa_printf(MSG_DEBUG, "EAP-FAST: Received %lu bytes encrypted data for"
                   " Phase 2", (unsigned long) in_len);

        if (data->pending_phase2_resp) {
                wpa_printf(MSG_DEBUG, "EAP-PEAP: Pending Phase 2 response - "
                           "skip decryption and use old data");
                eap_fast_process_phase2_tlvs(
                        sm, data, wpabuf_mhead(data->pending_phase2_resp),
                        wpabuf_len(data->pending_phase2_resp));
                wpabuf_free(data->pending_phase2_resp);
                data->pending_phase2_resp = NULL;
                return;
        }

        buf_len = in_len;
        /*
         * Even though we try to disable TLS compression, it is possible that
         * this cannot be done with all TLS libraries. Add extra buffer space
         * to handle the possibility of the decrypted data being longer than
         * input data.
         */
        buf_len += 500;
        buf_len *= 3;
        in_decrypted = os_malloc(buf_len);
        if (in_decrypted == NULL) {
                wpa_printf(MSG_WARNING, "EAP-FAST: Failed to allocate memory "
                           "for decryption");
                return;
        }

        len_decrypted = tls_connection_decrypt(sm->ssl_ctx, data->ssl.conn,
                                               in_data, in_len,
                                               in_decrypted, buf_len);
        if (len_decrypted < 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to decrypt Phase 2 "
                           "data");
                os_free(in_decrypted);
                eap_fast_state(data, FAILURE);
                return;
        }

        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Decrypted Phase 2 TLVs",
                        in_decrypted, len_decrypted);

        eap_fast_process_phase2_tlvs(sm, data, in_decrypted, len_decrypted);

        if (sm->method_pending == METHOD_PENDING_WAIT) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Phase2 method is in "
                           "pending wait state - save decrypted response");
                wpabuf_free(data->pending_phase2_resp);
                data->pending_phase2_resp = wpabuf_alloc_copy(in_decrypted,
                                                              len_decrypted);
        }

        os_free(in_decrypted);
}


static int eap_fast_process_version(struct eap_sm *sm, void *priv,
                                    int peer_version)
{
        struct eap_fast_data *data = priv;

        data->peer_version = peer_version;

        if (data->force_version >= 0 && peer_version != data->force_version) {
                wpa_printf(MSG_INFO, "EAP-FAST: peer did not select the forced"
                           " version (forced=%d peer=%d) - reject",
                           data->force_version, peer_version);
                return -1;
        }

        if (peer_version < data->fast_version) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: peer ver=%d, own ver=%d; "
                           "use version %d",
                           peer_version, data->fast_version, peer_version);
                data->fast_version = peer_version;
        }

        return 0;
}


static int eap_fast_process_phase1(struct eap_sm *sm,
                                   struct eap_fast_data *data)
{
        if (eap_server_tls_phase1(sm, &data->ssl) < 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: TLS processing failed");
                eap_fast_state(data, FAILURE);
                return -1;
        }

        if (!tls_connection_established(sm->ssl_ctx, data->ssl.conn) ||
            wpabuf_len(data->ssl.out_buf) > 0)
                return 1;

        /*
         * Phase 1 was completed with the received message (e.g., when using
         * abbreviated handshake), so Phase 2 can be started immediately
         * without having to send through an empty message to the peer.
         */

        return eap_fast_phase1_done(sm, data);
}


static void eap_fast_process_phase2_start(struct eap_sm *sm,
                                          struct eap_fast_data *data)
{
        u8 next_type;

        if (data->identity) {
                os_free(sm->identity);
                sm->identity = data->identity;
                data->identity = NULL;
                sm->identity_len = data->identity_len;
                data->identity_len = 0;
                sm->require_identity_match = 1;
                if (eap_user_get(sm, sm->identity, sm->identity_len, 1) != 0) {
                        wpa_hexdump_ascii(MSG_DEBUG, "EAP-FAST: "
                                          "Phase2 Identity not found "
                                          "in the user database",
                                          sm->identity, sm->identity_len);
                        next_type = eap_fast_req_failure(sm, data);
                } else {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Identity already "
                                   "known - skip Phase 2 Identity Request");
                        next_type = sm->user->methods[0].method;
                        sm->user_eap_method_index = 1;
                }

                eap_fast_state(data, PHASE2_METHOD);
        } else {
                eap_fast_state(data, PHASE2_ID);
                next_type = EAP_TYPE_IDENTITY;
        }

        eap_fast_phase2_init(sm, data, next_type);
}


static void eap_fast_process_msg(struct eap_sm *sm, void *priv,
                                 const struct wpabuf *respData)
{
        struct eap_fast_data *data = priv;

        switch (data->state) {
        case PHASE1:
                if (eap_fast_process_phase1(sm, data))
                        break;

                /* fall through to PHASE2_START */
        case PHASE2_START:
                eap_fast_process_phase2_start(sm, data);
                break;
        case PHASE2_ID:
        case PHASE2_METHOD:
        case CRYPTO_BINDING:
        case REQUEST_PAC:
                eap_fast_process_phase2(sm, data, data->ssl.in_buf);
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-FAST: Unexpected state %d in %s",
                           data->state, __func__);
                break;
        }
}


static void eap_fast_process(struct eap_sm *sm, void *priv,
                             struct wpabuf *respData)
{
        struct eap_fast_data *data = priv;
        if (eap_server_tls_process(sm, &data->ssl, respData, data,
                                   EAP_TYPE_FAST, eap_fast_process_version,
                                   eap_fast_process_msg) < 0)
                eap_fast_state(data, FAILURE);
}


static Boolean eap_fast_isDone(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        return data->state == SUCCESS || data->state == FAILURE;
}


static u8 * eap_fast_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_fast_data *data = priv;
        u8 *eapKeyData;

        if (data->state != SUCCESS)
                return NULL;

        eapKeyData = os_malloc(EAP_FAST_KEY_LEN);
        if (eapKeyData == NULL)
                return NULL;

        eap_fast_derive_eap_msk(data->simck, eapKeyData);
        *len = EAP_FAST_KEY_LEN;

        return eapKeyData;
}


static u8 * eap_fast_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_fast_data *data = priv;
        u8 *eapKeyData;

        if (data->state != SUCCESS)
                return NULL;

        eapKeyData = os_malloc(EAP_EMSK_LEN);
        if (eapKeyData == NULL)
                return NULL;

        eap_fast_derive_eap_emsk(data->simck, eapKeyData);
        *len = EAP_EMSK_LEN;

        return eapKeyData;
}


static Boolean eap_fast_isSuccess(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        return data->state == SUCCESS;
}


int eap_server_fast_register(void)
{
        struct eap_method *eap;
        int ret;

        eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
                                      EAP_VENDOR_IETF, EAP_TYPE_FAST, "FAST");
        if (eap == NULL)
                return -1;

        eap->init = eap_fast_init;
        eap->reset = eap_fast_reset;
        eap->buildReq = eap_fast_buildReq;
        eap->check = eap_fast_check;
        eap->process = eap_fast_process;
        eap->isDone = eap_fast_isDone;
        eap->getKey = eap_fast_getKey;
        eap->get_emsk = eap_fast_get_emsk;
        eap->isSuccess = eap_fast_isSuccess;

        ret = eap_server_method_register(eap);
        if (ret)
                eap_server_method_free(eap);
        return ret;
}