eap_aka.c

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#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "common.h"
#include "eap_i.h"
#include "wpa_supplicant.h"
#include "config_ssid.h"
#include "crypto.h"
#include "pcsc_funcs.h"
#include "eap_sim_common.h"

/* EAP-AKA Subtypes */
#define EAP_AKA_SUBTYPE_CHALLENGE 1
#define EAP_AKA_SUBTYPE_AUTHENTICATION_REJECT 2
#define EAP_AKA_SUBTYPE_SYNCHRONIZATION_FAILURE 4
#define EAP_AKA_SUBTYPE_IDENTITY 5
#define EAP_AKA_SUBTYPE_NOTIFICATION 12
#define EAP_AKA_SUBTYPE_REAUTHENTICATION 13
#define EAP_AKA_SUBTYPE_CLIENT_ERROR 14

/* AT_CLIENT_ERROR_CODE error codes */
#define EAP_AKA_UNABLE_TO_PROCESS_PACKET 0

#define AKA_AUTS_LEN 14
#define RES_MAX_LEN 16
#define IK_LEN 16
#define CK_LEN 16
#define EAP_AKA_MAX_FAST_REAUTHS 1000

struct eap_aka_data {
        u8 ik[IK_LEN], ck[CK_LEN], res[RES_MAX_LEN];
        size_t res_len;
        u8 nonce_s[EAP_SIM_NONCE_S_LEN];
        u8 mk[EAP_SIM_MK_LEN];
        u8 k_aut[EAP_SIM_K_AUT_LEN];
        u8 k_encr[EAP_SIM_K_ENCR_LEN];
        u8 msk[EAP_SIM_KEYING_DATA_LEN];
        u8 rand[AKA_RAND_LEN], autn[AKA_AUTN_LEN];
        u8 auts[AKA_AUTS_LEN];

        int num_id_req, num_notification;
        u8 *pseudonym;
        size_t pseudonym_len;
        u8 *reauth_id;
        size_t reauth_id_len;
        int reauth;
        unsigned int counter, counter_too_small;
        u8 *last_eap_identity;
        size_t last_eap_identity_len;
        enum { CONTINUE, SUCCESS, FAILURE } state;
};


static void * eap_aka_init(struct eap_sm *sm)
{
        struct eap_aka_data *data;
        data = malloc(sizeof(*data));
        if (data == NULL)
                return NULL;
        memset(data, 0, sizeof(*data));

        data->state = CONTINUE;

        return data;
}


static void eap_aka_deinit(struct eap_sm *sm, void *priv)
{
        struct eap_aka_data *data = priv;
        if (data) {
                free(data->pseudonym);
                free(data->reauth_id);
                free(data->last_eap_identity);
                free(data);
        }
}


static int eap_aka_umts_auth(struct eap_sm *sm, struct eap_aka_data *data)
{
        wpa_printf(MSG_DEBUG, "EAP-AKA: UMTS authentication algorithm");
#ifdef PCSC_FUNCS
        return scard_umts_auth(sm->scard_ctx, data->rand,
                               data->autn, data->res, &data->res_len,
                               data->ik, data->ck, data->auts);
#else /* PCSC_FUNCS */
        /* These hardcoded Kc and SRES values are used for testing.
         * Could consider making them configurable. */
        memset(data->res, '2', RES_MAX_LEN);
        data->res_len = 16;
        memset(data->ik, '3', IK_LEN);
        memset(data->ck, '4', CK_LEN);
        {
                u8 autn[AKA_AUTN_LEN];
                memset(autn, '1', AKA_AUTN_LEN);
                if (memcmp(autn, data->autn, AKA_AUTN_LEN) != 0) {
                        wpa_printf(MSG_WARNING, "EAP-AKA: AUTN did not match "
                                   "with expected value");
                        return -1;
                }
        }
        return 0;
#endif /* PCSC_FUNCS */
}


static void eap_aka_derive_mk(struct eap_aka_data *data,
                              const u8 *identity, size_t identity_len)
{
        const u8 *addr[3];
        size_t len[3];

        addr[0] = identity;
        len[0] = identity_len;
        addr[1] = data->ik;
        len[1] = IK_LEN;
        addr[2] = data->ck;
        len[2] = CK_LEN;

        /* MK = SHA1(Identity|IK|CK) */
        sha1_vector(3, addr, len, data->mk);
        wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: IK", data->ik, IK_LEN);
        wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: CK", data->ck, CK_LEN);
        wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: MK", data->mk, EAP_SIM_MK_LEN);
}


#define CLEAR_PSEUDONYM 0x01
#define CLEAR_REAUTH_ID 0x02
#define CLEAR_EAP_ID    0x04

static void eap_aka_clear_identities(struct eap_aka_data *data, int id)
{
        wpa_printf(MSG_DEBUG, "EAP-AKA: forgetting old%s%s%s",
                   id & CLEAR_PSEUDONYM ? " pseudonym" : "",
                   id & CLEAR_REAUTH_ID ? " reauth_id" : "",
                   id & CLEAR_EAP_ID ? " eap_id" : "");
        if (id & CLEAR_PSEUDONYM) {
                free(data->pseudonym);
                data->pseudonym = NULL;
                data->pseudonym_len = 0;
        }
        if (id & CLEAR_REAUTH_ID) {
                free(data->reauth_id);
                data->reauth_id = NULL;
                data->reauth_id_len = 0;
        }
        if (id & CLEAR_EAP_ID) {
                free(data->last_eap_identity);
                data->last_eap_identity = NULL;
                data->last_eap_identity_len = 0;
        }
}


static int eap_aka_learn_ids(struct eap_aka_data *data,
                             struct eap_sim_attrs *attr)
{
        if (attr->next_pseudonym) {
                free(data->pseudonym);
                data->pseudonym = malloc(attr->next_pseudonym_len);
                if (data->pseudonym == NULL) {
                        wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
                                   "next pseudonym");
                        return -1;
                }
                memcpy(data->pseudonym, attr->next_pseudonym,
                       attr->next_pseudonym_len);
                data->pseudonym_len = attr->next_pseudonym_len;
                wpa_hexdump_ascii(MSG_DEBUG,
                                  "EAP-AKA: (encr) AT_NEXT_PSEUDONYM",
                                  data->pseudonym,
                                  data->pseudonym_len);
        }

        if (attr->next_reauth_id) {
                free(data->reauth_id);
                data->reauth_id = malloc(attr->next_reauth_id_len);
                if (data->reauth_id == NULL) {
                        wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
                                   "next reauth_id");
                        return -1;
                }
                memcpy(data->reauth_id, attr->next_reauth_id,
                       attr->next_reauth_id_len);
                data->reauth_id_len = attr->next_reauth_id_len;
                wpa_hexdump_ascii(MSG_DEBUG,
                                  "EAP-AKA: (encr) AT_NEXT_REAUTH_ID",
                                  data->reauth_id,
                                  data->reauth_id_len);
        }

        return 0;
}


static u8 * eap_aka_client_error(struct eap_sm *sm, struct eap_aka_data *data,
                                 const struct eap_hdr *req,
                                 size_t *respDataLen, int err)
{
        struct eap_sim_msg *msg;

        data->state = FAILURE;
        data->num_id_req = 0;
        data->num_notification = 0;

        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
                               EAP_TYPE_AKA, EAP_AKA_SUBTYPE_CLIENT_ERROR);
        eap_sim_msg_add(msg, EAP_SIM_AT_CLIENT_ERROR_CODE, err, NULL, 0);
        return eap_sim_msg_finish(msg, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_authentication_reject(struct eap_sm *sm,
                                          struct eap_aka_data *data,
                                          const struct eap_hdr *req,
                                          size_t *respDataLen)
{
        struct eap_sim_msg *msg;

        data->state = FAILURE;
        data->num_id_req = 0;
        data->num_notification = 0;

        wpa_printf(MSG_DEBUG, "Generating EAP-AKA Authentication-Reject "
                   "(id=%d)", req->identifier);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
                               EAP_TYPE_AKA,
                               EAP_AKA_SUBTYPE_AUTHENTICATION_REJECT);
        return eap_sim_msg_finish(msg, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_synchronization_failure(struct eap_sm *sm,
                                            struct eap_aka_data *data,
                                            const struct eap_hdr *req,
                                            size_t *respDataLen)
{
        struct eap_sim_msg *msg;

        data->state = FAILURE;
        data->num_id_req = 0;
        data->num_notification = 0;

        wpa_printf(MSG_DEBUG, "Generating EAP-AKA Synchronization-Failure "
                   "(id=%d)", req->identifier);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
                               EAP_TYPE_AKA,
                               EAP_AKA_SUBTYPE_SYNCHRONIZATION_FAILURE);
        wpa_printf(MSG_DEBUG, "   AT_AUTS");
        eap_sim_msg_add_full(msg, EAP_SIM_AT_AUTS, data->auts, AKA_AUTS_LEN);
        return eap_sim_msg_finish(msg, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_response_identity(struct eap_sm *sm,
                                      struct eap_aka_data *data,
                                      const struct eap_hdr *req,
                                      size_t *respDataLen,
                                      enum eap_sim_id_req id_req)
{
        struct wpa_ssid *config = eap_get_config(sm);
        u8 *identity = NULL;
        size_t identity_len = 0;
        struct eap_sim_msg *msg;

        data->reauth = 0;
        if (id_req == ANY_ID && data->reauth_id) {
                identity = data->reauth_id;
                identity_len = data->reauth_id_len;
                data->reauth = 1;
        } else if ((id_req == ANY_ID || id_req == FULLAUTH_ID) &&
                   data->pseudonym) {
                identity = data->pseudonym;
                identity_len = data->pseudonym_len;
                eap_aka_clear_identities(data, CLEAR_REAUTH_ID);
        } else if (id_req != NO_ID_REQ && config && config->identity) {
                identity = config->identity;
                identity_len = config->identity_len;
                eap_aka_clear_identities(data,
                                         CLEAR_PSEUDONYM | CLEAR_REAUTH_ID);
        }
        if (id_req != NO_ID_REQ)
                eap_aka_clear_identities(data, CLEAR_EAP_ID);

        wpa_printf(MSG_DEBUG, "Generating EAP-AKA Identity (id=%d)",
                   req->identifier);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
                               EAP_TYPE_AKA, EAP_AKA_SUBTYPE_IDENTITY);

        if (identity) {
                wpa_hexdump_ascii(MSG_DEBUG, "   AT_IDENTITY",
                                  identity, identity_len);
                eap_sim_msg_add(msg, EAP_SIM_AT_IDENTITY, identity_len,
                                identity, identity_len);
        }

        return eap_sim_msg_finish(msg, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_response_challenge(struct eap_sm *sm,
                                       struct eap_aka_data *data,
                                       const struct eap_hdr *req,
                                       size_t *respDataLen)
{
        struct eap_sim_msg *msg;

        wpa_printf(MSG_DEBUG, "Generating EAP-AKA Challenge (id=%d)",
                   req->identifier);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
                               EAP_TYPE_AKA, EAP_AKA_SUBTYPE_CHALLENGE);
        wpa_printf(MSG_DEBUG, "   AT_RES");
        eap_sim_msg_add(msg, EAP_SIM_AT_RES, data->res_len,
                        data->res, data->res_len);
        wpa_printf(MSG_DEBUG, "   AT_MAC");
        eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
        return eap_sim_msg_finish(msg, respDataLen, data->k_aut, (u8 *) "", 0);
}


static u8 * eap_aka_response_reauth(struct eap_sm *sm,
                                    struct eap_aka_data *data,
                                    const struct eap_hdr *req,
                                    size_t *respDataLen, int counter_too_small)
{
        struct eap_sim_msg *msg;
        unsigned int counter;

        wpa_printf(MSG_DEBUG, "Generating EAP-AKA Reauthentication (id=%d)",
                   req->identifier);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
                               EAP_TYPE_AKA,
                               EAP_AKA_SUBTYPE_REAUTHENTICATION);
        wpa_printf(MSG_DEBUG, "   AT_IV");
        wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
        eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV, EAP_SIM_AT_ENCR_DATA);

        if (counter_too_small) {
                wpa_printf(MSG_DEBUG, "   *AT_COUNTER_TOO_SMALL");
                eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER_TOO_SMALL, 0, NULL, 0);
                counter = data->counter_too_small;
        } else
                counter = data->counter;

        wpa_printf(MSG_DEBUG, "   *AT_COUNTER %d", counter);
        eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, counter, NULL, 0);

        if (eap_sim_msg_add_encr_end(msg, data->k_encr, EAP_SIM_AT_PADDING)) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Failed to encrypt "
                           "AT_ENCR_DATA");
                eap_sim_msg_free(msg);
                return NULL;
        }
        wpa_printf(MSG_DEBUG, "   AT_MAC");
        eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
        return eap_sim_msg_finish(msg, respDataLen, data->k_aut, data->nonce_s,
                                  EAP_SIM_NONCE_S_LEN);
}


static u8 * eap_aka_response_notification(struct eap_sm *sm,
                                          struct eap_aka_data *data,
                                          const struct eap_hdr *req,
                                          size_t *respDataLen,
                                          u16 notification)
{
        struct eap_sim_msg *msg;
        u8 *k_aut = (notification & 0x4000) == 0 ? data->k_aut : NULL;

        wpa_printf(MSG_DEBUG, "Generating EAP-AKA Notification (id=%d)",
                   req->identifier);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
                               EAP_TYPE_AKA, EAP_AKA_SUBTYPE_NOTIFICATION);
        wpa_printf(MSG_DEBUG, "   AT_NOTIFICATION");
        eap_sim_msg_add(msg, EAP_SIM_AT_NOTIFICATION, notification, NULL, 0);
        if (k_aut && data->reauth) {
                wpa_printf(MSG_DEBUG, "   AT_IV");
                wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
                eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV,
                                           EAP_SIM_AT_ENCR_DATA);
                wpa_printf(MSG_DEBUG, "   *AT_COUNTER %d", data->counter);
                eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, data->counter,
                                NULL, 0);
                if (eap_sim_msg_add_encr_end(msg, data->k_encr,
                                             EAP_SIM_AT_PADDING)) {
                        wpa_printf(MSG_WARNING, "EAP-AKA: Failed to encrypt "
                                   "AT_ENCR_DATA");
                        eap_sim_msg_free(msg);
                        return NULL;
                }
        }
        if (k_aut) {
                wpa_printf(MSG_DEBUG, "   AT_MAC");
                eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
        }
        return eap_sim_msg_finish(msg, respDataLen, k_aut, (u8 *) "", 0);
}


static u8 * eap_aka_process_identity(struct eap_sm *sm,
                                     struct eap_aka_data *data,
                                     const struct eap_hdr *req,
                                     size_t reqDataLen,
                                     size_t *respDataLen,
                                     struct eap_sim_attrs *attr)
{
        int id_error;

        wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Identity");

        id_error = 0;
        switch (attr->id_req) {
        case NO_ID_REQ:
                break;
        case ANY_ID:
                if (data->num_id_req > 0)
                        id_error++;
                data->num_id_req++;
                break;
        case FULLAUTH_ID:
                if (data->num_id_req > 1)
                        id_error++;
                data->num_id_req++;
                break;
        case PERMANENT_ID:
                if (data->num_id_req > 2)
                        id_error++;
                data->num_id_req++;
                break;
        }
        if (id_error) {
                wpa_printf(MSG_INFO, "EAP-AKA: Too many ID requests "
                           "used within one authentication");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        return eap_aka_response_identity(sm, data, req, respDataLen,
                                         attr->id_req);
}


static u8 * eap_aka_process_challenge(struct eap_sm *sm,
                                      struct eap_aka_data *data,
                                      const struct eap_hdr *req,
                                      size_t reqDataLen,
                                      size_t *respDataLen,
                                      struct eap_sim_attrs *attr)
{
        struct wpa_ssid *config = eap_get_config(sm);
        u8 *identity;
        size_t identity_len;
        int res;
        struct eap_sim_attrs eattr;

        wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Challenge");
        data->reauth = 0;
        if (!attr->mac || !attr->rand || !attr->autn) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
                           "did not include%s%s%s",
                           !attr->mac ? " AT_MAC" : "",
                           !attr->rand ? " AT_RAND" : "",
                           !attr->autn ? " AT_AUTN" : "");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }
        memcpy(data->rand, attr->rand, AKA_RAND_LEN);
        memcpy(data->autn, attr->autn, AKA_AUTN_LEN);

        res = eap_aka_umts_auth(sm, data);
        if (res == -1) {
                wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication "
                           "failed (AUTN)");
                return eap_aka_authentication_reject(sm, data, req,
                                                     respDataLen);
        } else if (res == -2) {
                wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication "
                           "failed (AUTN seq# -> AUTS)");
                return eap_aka_synchronization_failure(sm, data, req,
                                                       respDataLen);
        } else if (res) {
                wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication failed");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }
        if (data->last_eap_identity) {
                identity = data->last_eap_identity;
                identity_len = data->last_eap_identity_len;
        } else if (data->pseudonym) {
                identity = data->pseudonym;
                identity_len = data->pseudonym_len;
        } else {
                identity = config->identity;
                identity_len = config->identity_len;
        }
        wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Selected identity for MK "
                          "derivation", identity, identity_len);
        eap_aka_derive_mk(data, identity, identity_len);
        eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk);
        if (eap_sim_verify_mac(data->k_aut, (const u8 *) req, reqDataLen,
                               attr->mac, (u8 *) "", 0)) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
                           "used invalid AT_MAC");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        /* Old reauthentication and pseudonym identities must not be used
         * anymore. In other words, if no new identities are received, full
         * authentication will be used on next reauthentication. */
        eap_aka_clear_identities(data, CLEAR_PSEUDONYM | CLEAR_REAUTH_ID |
                                 CLEAR_EAP_ID);

        if (attr->encr_data) {
                u8 *decrypted;
                decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
                                               attr->encr_data_len, attr->iv,
                                               &eattr, 0);
                if (decrypted == NULL) {
                        return eap_aka_client_error(
                                sm, data, req, respDataLen,
                                EAP_AKA_UNABLE_TO_PROCESS_PACKET);
                }
                eap_aka_learn_ids(data, &eattr);
                free(decrypted);
        }

        if (data->state != FAILURE)
                data->state = SUCCESS;

        data->num_id_req = 0;
        data->num_notification = 0;
        /* draft-arkko-pppext-eap-aka-12.txt specifies that counter
         * is initialized to one after fullauth, but initializing it to
         * zero makes it easier to implement reauth verification. */
        data->counter = 0;
        return eap_aka_response_challenge(sm, data, req, respDataLen);
}


static int eap_aka_process_notification_reauth(struct eap_aka_data *data,
                                               const struct eap_hdr *req,
                                               size_t reqDataLen,
                                               struct eap_sim_attrs *attr)
{
        struct eap_sim_attrs eattr;
        u8 *decrypted;

        if (attr->encr_data == NULL || attr->iv == NULL) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Notification message after "
                           "reauth did not include encrypted data");
                return -1;
        }

        decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
                                       attr->encr_data_len, attr->iv, &eattr,
                                       0);
        if (decrypted == NULL) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Failed to parse encrypted "
                           "data from notification message");
                return -1;
        }

        if (eattr.counter != data->counter) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Counter in notification "
                           "message does not match with counter in reauth "
                           "message");
                free(decrypted);
                return -1;
        }

        free(decrypted);
        return 0;
}


static int eap_aka_process_notification_auth(struct eap_aka_data *data,
                                             const struct eap_hdr *req,
                                             size_t reqDataLen,
                                             struct eap_sim_attrs *attr)
{
        if (attr->mac == NULL) {
                wpa_printf(MSG_INFO, "EAP-AKA: no AT_MAC in after_auth "
                           "Notification message");
                return -1;
        }

        if (eap_sim_verify_mac(data->k_aut, (const u8 *) req, reqDataLen,
                               attr->mac, (u8 *) "", 0)) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Notification message "
                           "used invalid AT_MAC");
                return -1;
        }

        if (data->reauth &&
            eap_aka_process_notification_reauth(data, req, reqDataLen, attr)) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Invalid notification "
                           "message after reauth");
                return -1;
        }

        return 0;
}


static u8 * eap_aka_process_notification(struct eap_sm *sm,
                                         struct eap_aka_data *data,
                                         const struct eap_hdr *req,
                                         size_t reqDataLen,
                                         size_t *respDataLen,
                                         struct eap_sim_attrs *attr)
{
        wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Notification");
        if (data->num_notification > 0) {
                wpa_printf(MSG_INFO, "EAP-AKA: too many notification "
                           "rounds (only one allowed)");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }
        data->num_notification++;
        if (attr->notification == -1) {
                wpa_printf(MSG_INFO, "EAP-AKA: no AT_NOTIFICATION in "
                           "Notification message");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        if ((attr->notification & 0x4000) == 0 &&
            eap_aka_process_notification_auth(data, req, reqDataLen, attr)) {
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        eap_sim_report_notification(sm->msg_ctx, attr->notification, 1);
        if (attr->notification >= 0 && attr->notification < 32768) {
                data->state = FAILURE;
        }
        return eap_aka_response_notification(sm, data, req, respDataLen,
                                             attr->notification);
}


static u8 * eap_aka_process_reauthentication(struct eap_sm *sm,
                                             struct eap_aka_data *data,
                                             const struct eap_hdr *req,
                                             size_t reqDataLen,
                                             size_t *respDataLen,
                                             struct eap_sim_attrs *attr)
{
        struct eap_sim_attrs eattr;
        u8 *decrypted;

        wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Reauthentication");

        if (data->reauth_id == NULL) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Server is trying "
                           "reauthentication, but no reauth_id available");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        data->reauth = 1;
        if (eap_sim_verify_mac(data->k_aut, (const u8 *) req, reqDataLen,
                               attr->mac, (u8 *) "", 0)) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
                           "did not have valid AT_MAC");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        if (attr->encr_data == NULL || attr->iv == NULL) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
                           "message did not include encrypted data");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
                                       attr->encr_data_len, attr->iv, &eattr,
                                       0);
        if (decrypted == NULL) {
                wpa_printf(MSG_WARNING, "EAP-AKA: Failed to parse encrypted "
                           "data from reauthentication message");
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        if (eattr.nonce_s == NULL || eattr.counter < 0) {
                wpa_printf(MSG_INFO, "EAP-AKA: (encr) No%s%s in reauth packet",
                           !eattr.nonce_s ? " AT_NONCE_S" : "",
                           eattr.counter < 0 ? " AT_COUNTER" : "");
                free(decrypted);
                return eap_aka_client_error(sm, data, req, respDataLen,
                                            EAP_AKA_UNABLE_TO_PROCESS_PACKET);
        }

        if (eattr.counter <= data->counter) {
                wpa_printf(MSG_INFO, "EAP-AKA: (encr) Invalid counter "
                           "(%d <= %d)", eattr.counter, data->counter);
                data->counter_too_small = eattr.counter;
                /* Reply using Re-auth w/ AT_COUNTER_TOO_SMALL. The current
                 * reauth_id must not be used to start a new reauthentication.
                 * However, since it was used in the last EAP-Response-Identity
                 * packet, it has to saved for the following fullauth to be
                 * used in MK derivation. */
                free(data->last_eap_identity);
                data->last_eap_identity = data->reauth_id;
                data->last_eap_identity_len = data->reauth_id_len;
                data->reauth_id = NULL;
                data->reauth_id_len = 0;
                free(decrypted);
                return eap_aka_response_reauth(sm, data, req, respDataLen, 1);
        }
        data->counter = eattr.counter;

        memcpy(data->nonce_s, eattr.nonce_s, EAP_SIM_NONCE_S_LEN);
        wpa_hexdump(MSG_DEBUG, "EAP-AKA: (encr) AT_NONCE_S",
                    data->nonce_s, EAP_SIM_NONCE_S_LEN);

        eap_sim_derive_keys_reauth(data->counter,
                                   data->reauth_id, data->reauth_id_len,
                                   data->nonce_s, data->mk, data->msk);
        eap_aka_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
        eap_aka_learn_ids(data, &eattr);

        if (data->state != FAILURE)
                data->state = SUCCESS;

        data->num_id_req = 0;
        data->num_notification = 0;
        if (data->counter > EAP_AKA_MAX_FAST_REAUTHS) {
                wpa_printf(MSG_DEBUG, "EAP-AKA: Maximum number of "
                           "fast reauths performed - force fullauth");
                eap_aka_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
        }
        free(decrypted);
        return eap_aka_response_reauth(sm, data, req, respDataLen, 0);
}


static u8 * eap_aka_process(struct eap_sm *sm, void *priv,
                            struct eap_method_ret *ret,
                            const u8 *reqData, size_t reqDataLen,
                            size_t *respDataLen)
{
        struct eap_aka_data *data = priv;
        struct wpa_ssid *config = eap_get_config(sm);
        const struct eap_hdr *req;
        u8 subtype, *res;
        const u8 *pos;
        struct eap_sim_attrs attr;
        size_t len;

        wpa_hexdump(MSG_DEBUG, "EAP-AKA: EAP data", reqData, reqDataLen);
        if (config == NULL || config->identity == NULL) {
                wpa_printf(MSG_INFO, "EAP-AKA: Identity not configured");
                eap_sm_request_identity(sm, config);
                ret->ignore = TRUE;
                return NULL;
        }

        pos = eap_hdr_validate(EAP_TYPE_AKA, reqData, reqDataLen, &len);
        if (pos == NULL || len < 1) {
                ret->ignore = TRUE;
                return NULL;
        }
        req = (const struct eap_hdr *) reqData;
        len = be_to_host16(req->length);

        ret->ignore = FALSE;
        ret->methodState = METHOD_MAY_CONT;
        ret->decision = DECISION_FAIL;
        ret->allowNotifications = TRUE;

        subtype = *pos++;
        wpa_printf(MSG_DEBUG, "EAP-AKA: Subtype=%d", subtype);
        pos += 2; /* Reserved */

        if (eap_sim_parse_attr(pos, reqData + len, &attr, 1, 0)) {
                res = eap_aka_client_error(sm, data, req, respDataLen,
                                           EAP_AKA_UNABLE_TO_PROCESS_PACKET);
                goto done;
        }

        switch (subtype) {
        case EAP_AKA_SUBTYPE_IDENTITY:
                res = eap_aka_process_identity(sm, data, req, len,
                                               respDataLen, &attr);
                break;
        case EAP_AKA_SUBTYPE_CHALLENGE:
                res = eap_aka_process_challenge(sm, data, req, len,
                                                respDataLen, &attr);
                break;
        case EAP_AKA_SUBTYPE_NOTIFICATION:
                res = eap_aka_process_notification(sm, data, req, len,
                                                   respDataLen, &attr);
                break;
        case EAP_AKA_SUBTYPE_REAUTHENTICATION:
                res = eap_aka_process_reauthentication(sm, data, req, len,
                                                       respDataLen, &attr);
                break;
        case EAP_AKA_SUBTYPE_CLIENT_ERROR:
                wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Client-Error");
                res = eap_aka_client_error(sm, data, req, respDataLen,
                                           EAP_AKA_UNABLE_TO_PROCESS_PACKET);
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-AKA: Unknown subtype=%d", subtype);
                res = eap_aka_client_error(sm, data, req, respDataLen,
                                           EAP_AKA_UNABLE_TO_PROCESS_PACKET);
                break;
        }

done:
        if (data->state == FAILURE) {
                ret->decision = DECISION_FAIL;
                ret->methodState = METHOD_DONE;
        } else if (data->state == SUCCESS) {
                ret->decision = DECISION_COND_SUCC;
                ret->methodState = METHOD_DONE;
        }

        if (ret->methodState == METHOD_DONE) {
                ret->allowNotifications = FALSE;
        }

        return res;
}


static Boolean eap_aka_has_reauth_data(struct eap_sm *sm, void *priv)
{
        struct eap_aka_data *data = priv;
        return data->pseudonym || data->reauth_id;
}


static void eap_aka_deinit_for_reauth(struct eap_sm *sm, void *priv)
{
        struct eap_aka_data *data = priv;
        eap_aka_clear_identities(data, CLEAR_EAP_ID);
}


static void * eap_aka_init_for_reauth(struct eap_sm *sm, void *priv)
{
        struct eap_aka_data *data = priv;
        data->num_id_req = 0;
        data->num_notification = 0;
        data->state = CONTINUE;
        return priv;
}


static const u8 * eap_aka_get_identity(struct eap_sm *sm, void *priv,
                                       size_t *len)
{
        struct eap_aka_data *data = priv;

        if (data->reauth_id) {
                *len = data->reauth_id_len;
                return data->reauth_id;
        }

        if (data->pseudonym) {
                *len = data->pseudonym_len;
                return data->pseudonym;
        }

        return NULL;
}


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


static u8 * eap_aka_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_aka_data *data = priv;
        u8 *key;

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

        key = malloc(EAP_SIM_KEYING_DATA_LEN);
        if (key == NULL)
                return NULL;

        *len = EAP_SIM_KEYING_DATA_LEN;
        memcpy(key, data->msk, EAP_SIM_KEYING_DATA_LEN);

        return key;
}


const struct eap_method eap_method_aka =
{
        .method = EAP_TYPE_AKA,
        .name = "AKA",
        .init = eap_aka_init,
        .deinit = eap_aka_deinit,
        .process = eap_aka_process,
        .isKeyAvailable = eap_aka_isKeyAvailable,
        .getKey = eap_aka_getKey,
        .has_reauth_data = eap_aka_has_reauth_data,
        .deinit_for_reauth = eap_aka_deinit_for_reauth,
        .init_for_reauth = eap_aka_init_for_reauth,
        .get_identity = eap_aka_get_identity,
};

---