/src/hostap/src/eap_peer/eap_aka.c

Source (jump to first uncovered line)
/*
 * EAP peer method: EAP-AKA (RFC 4187) and EAP-AKA' (RFC 5448)
 * Copyright (c) 2004-2012, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "utils/base64.h"
#include "pcsc_funcs.h"
#include "crypto/crypto.h"
#include "crypto/sha1.h"
#include "crypto/sha256.h"
#include "crypto/milenage.h"
#include "eap_common/eap_sim_common.h"
#include "eap_config.h"
#include "eap_i.h"


struct eap_aka_data {
  u8 ik[EAP_AKA_IK_LEN], ck[EAP_AKA_CK_LEN], res[EAP_AKA_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_AKA_PRIME_K_AUT_LEN];
  u8 k_encr[EAP_SIM_K_ENCR_LEN];
  u8 k_re[EAP_AKA_PRIME_K_RE_LEN]; /* EAP-AKA' only */
  u8 msk[EAP_SIM_KEYING_DATA_LEN];
  u8 emsk[EAP_EMSK_LEN];
  u8 rand[EAP_AKA_RAND_LEN], autn[EAP_AKA_AUTN_LEN];
  u8 auts[EAP_AKA_AUTS_LEN];
  u8 reauth_mac[EAP_SIM_MAC_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 *mk_identity;
  size_t mk_identity_len;
  enum {
    CONTINUE, RESULT_SUCCESS, SUCCESS, FAILURE
  } state;

  struct wpabuf *id_msgs;
  int prev_id;
  int result_ind, use_result_ind;
  int use_pseudonym;
  u8 eap_method;
  u8 *network_name;
  size_t network_name_len;
  u16 kdf;
  int kdf_negotiation;
  u16 last_kdf_attrs[EAP_AKA_PRIME_KDF_MAX];
  size_t last_kdf_count;
  int error_code;
  struct crypto_rsa_key *imsi_privacy_key;
};


#ifndef CONFIG_NO_STDOUT_DEBUG
static const char * eap_aka_state_txt(int state)
{
  switch (state) {
  case CONTINUE:
    return "CONTINUE";
  case RESULT_SUCCESS:
    return "RESULT_SUCCESS";
  case SUCCESS:
    return "SUCCESS";
  case FAILURE:
    return "FAILURE";
  default:
    return "?";
  }
}
#endif /* CONFIG_NO_STDOUT_DEBUG */


static void eap_aka_state(struct eap_aka_data *data, int state)
{
  wpa_printf(MSG_DEBUG, "EAP-AKA: %s -> %s",
       eap_aka_state_txt(data->state),
       eap_aka_state_txt(state));
  data->state = state;
}


static void * eap_aka_init(struct eap_sm *sm)
{
  struct eap_aka_data *data;
  const char *phase1 = eap_get_config_phase1(sm);
  struct eap_peer_config *config = eap_get_config(sm);

  data = os_zalloc(sizeof(*data));
  if (data == NULL)
    return NULL;

  data->eap_method = EAP_TYPE_AKA;

  if (config && config->imsi_privacy_cert) {
#ifdef CRYPTO_RSA_OAEP_SHA256
    data->imsi_privacy_key = crypto_rsa_key_read(
      config->imsi_privacy_cert, false);
    if (!data->imsi_privacy_key) {
      wpa_printf(MSG_ERROR,
           "EAP-AKA: Failed to read/parse IMSI privacy certificate %s",
           config->imsi_privacy_cert);
      os_free(data);
      return NULL;
    }
#else /* CRYPTO_RSA_OAEP_SHA256 */
    wpa_printf(MSG_ERROR,
         "EAP-AKA: No support for imsi_privacy_cert in the build");
    os_free(data);
    return NULL;
#endif /* CRYPTO_RSA_OAEP_SHA256 */
  }

  /* Zero is a valid error code, so we need to initialize */
  data->error_code = NO_EAP_METHOD_ERROR;

  eap_aka_state(data, CONTINUE);
  data->prev_id = -1;

  data->result_ind = phase1 && os_strstr(phase1, "result_ind=1") != NULL;

  data->use_pseudonym = !sm->init_phase2;
  if (config && config->anonymous_identity && data->use_pseudonym) {
    data->pseudonym = os_malloc(config->anonymous_identity_len);
    if (data->pseudonym) {
      os_memcpy(data->pseudonym, config->anonymous_identity,
          config->anonymous_identity_len);
      data->pseudonym_len = config->anonymous_identity_len;
    }
  }

  if (sm->identity) {
    /* Use the EAP-Response/Identity in MK derivation if AT_IDENTITY
     * is not used. */
    data->mk_identity = os_memdup(sm->identity, sm->identity_len);
    data->mk_identity_len = sm->identity_len;
  }

  return data;
}


#ifdef EAP_AKA_PRIME
static void * eap_aka_prime_init(struct eap_sm *sm)
{
  struct eap_aka_data *data = eap_aka_init(sm);
  if (data == NULL)
    return NULL;
  data->eap_method = EAP_TYPE_AKA_PRIME;
  return data;
}
#endif /* EAP_AKA_PRIME */


static void eap_aka_clear_keys(struct eap_aka_data *data, int reauth)
{
  if (!reauth) {
    os_memset(data->mk, 0, EAP_SIM_MK_LEN);
    os_memset(data->k_aut, 0, EAP_AKA_PRIME_K_AUT_LEN);
    os_memset(data->k_encr, 0, EAP_SIM_K_ENCR_LEN);
    os_memset(data->k_re, 0, EAP_AKA_PRIME_K_RE_LEN);
  }
  os_memset(data->msk, 0, EAP_SIM_KEYING_DATA_LEN);
  os_memset(data->emsk, 0, EAP_EMSK_LEN);
  os_memset(data->autn, 0, EAP_AKA_AUTN_LEN);
  os_memset(data->auts, 0, EAP_AKA_AUTS_LEN);
}


static void eap_aka_deinit(struct eap_sm *sm, void *priv)
{
  struct eap_aka_data *data = priv;
  if (data) {
    os_free(data->pseudonym);
    os_free(data->reauth_id);
    os_free(data->mk_identity);
    wpabuf_free(data->id_msgs);
    os_free(data->network_name);
    eap_aka_clear_keys(data, 0);
#ifdef CRYPTO_RSA_OAEP_SHA256
    crypto_rsa_key_free(data->imsi_privacy_key);
#endif /* CRYPTO_RSA_OAEP_SHA256 */
    os_free(data);
  }
}


static int eap_aka_ext_sim_req(struct eap_sm *sm, struct eap_aka_data *data)
{
  char req[200], *pos, *end;

  wpa_printf(MSG_DEBUG, "EAP-AKA: Use external USIM processing");
  pos = req;
  end = pos + sizeof(req);
  pos += os_snprintf(pos, end - pos, "UMTS-AUTH");
  pos += os_snprintf(pos, end - pos, ":");
  pos += wpa_snprintf_hex(pos, end - pos, data->rand, EAP_AKA_RAND_LEN);
  pos += os_snprintf(pos, end - pos, ":");
  wpa_snprintf_hex(pos, end - pos, data->autn, EAP_AKA_AUTN_LEN);

  eap_sm_request_sim(sm, req);
  return 1;
}


static int eap_aka_ext_sim_result(struct eap_sm *sm, struct eap_aka_data *data,
          struct eap_peer_config *conf)
{
  char *resp, *pos;

  wpa_printf(MSG_DEBUG,
       "EAP-AKA: Use result from external USIM processing");

  resp = conf->external_sim_resp;
  conf->external_sim_resp = NULL;

  if (os_strncmp(resp, "UMTS-AUTS:", 10) == 0) {
    pos = resp + 10;
    if (hexstr2bin(pos, data->auts, EAP_AKA_AUTS_LEN) < 0)
      goto invalid;
    wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: AUTS", data->auts,
        EAP_AKA_AUTS_LEN);
    os_free(resp);
    return -2;
  }

  if (os_strncmp(resp, "UMTS-AUTH:", 10) != 0) {
    wpa_printf(MSG_DEBUG, "EAP-AKA: Unrecognized external USIM processing response");
    os_free(resp);
    return -1;
  }

  pos = resp + 10;
  wpa_hexdump(MSG_DEBUG, "EAP-AKA: RAND", data->rand, EAP_AKA_RAND_LEN);

  if (hexstr2bin(pos, data->ik, EAP_AKA_IK_LEN) < 0)
    goto invalid;
  wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: IK", data->ik, EAP_AKA_IK_LEN);
  pos += EAP_AKA_IK_LEN * 2;
  if (*pos != ':')
    goto invalid;
  pos++;

  if (hexstr2bin(pos, data->ck, EAP_AKA_CK_LEN) < 0)
    goto invalid;
  wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: CK", data->ck, EAP_AKA_CK_LEN);
  pos += EAP_AKA_CK_LEN * 2;
  if (*pos != ':')
    goto invalid;
  pos++;

  data->res_len = os_strlen(pos) / 2;
  if (data->res_len > EAP_AKA_RES_MAX_LEN) {
    data->res_len = 0;
    goto invalid;
  }
  if (hexstr2bin(pos, data->res, data->res_len) < 0)
    goto invalid;
  wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: RES", data->res, data->res_len);

  os_free(resp);
  return 0;

invalid:
  wpa_printf(MSG_DEBUG, "EAP-AKA: Invalid external USIM processing UMTS-AUTH response");
  os_free(resp);
  return -1;
}


static int eap_aka_umts_auth(struct eap_sm *sm, struct eap_aka_data *data)
{
  struct eap_peer_config *conf;

  wpa_printf(MSG_DEBUG, "EAP-AKA: UMTS authentication algorithm");

  conf = eap_get_config(sm);
  if (conf == NULL)
    return -1;

  if (sm->external_sim) {
    if (conf->external_sim_resp)
      return eap_aka_ext_sim_result(sm, data, conf);
    else
      return eap_aka_ext_sim_req(sm, data);
  }

  if (conf->pcsc) {
    return scard_umts_auth(sm->scard_ctx, data->rand,
               data->autn, data->res, &data->res_len,
               data->ik, data->ck, data->auts);
  }

#ifdef CONFIG_USIM_SIMULATOR
  if (conf->password) {
    u8 opc[16], k[16], sqn[6];
    const char *pos;
    wpa_printf(MSG_DEBUG, "EAP-AKA: Use internal Milenage "
         "implementation for UMTS authentication");
    if (conf->password_len < 78) {
      wpa_printf(MSG_DEBUG, "EAP-AKA: invalid Milenage "
           "password");
      return -1;
    }
    pos = (const char *) conf->password;
    if (hexstr2bin(pos, k, 16))
      return -1;
    pos += 32;
    if (*pos != ':')
      return -1;
    pos++;

    if (hexstr2bin(pos, opc, 16))
      return -1;
    pos += 32;
    if (*pos != ':')
      return -1;
    pos++;

    if (hexstr2bin(pos, sqn, 6))
      return -1;

    return milenage_check(opc, k, sqn, data->rand, data->autn,
              data->ik, data->ck,
              data->res, &data->res_len, data->auts);
  }
#endif /* CONFIG_USIM_SIMULATOR */

#ifdef CONFIG_USIM_HARDCODED
  wpa_printf(MSG_DEBUG, "EAP-AKA: Use hardcoded Kc and SRES values for "
       "testing");

  /* These hardcoded Kc and SRES values are used for testing.
   * Could consider making them configurable. */
  os_memset(data->res, '2', EAP_AKA_RES_MAX_LEN);
  data->res_len = EAP_AKA_RES_MAX_LEN;
  os_memset(data->ik, '3', EAP_AKA_IK_LEN);
  os_memset(data->ck, '4', EAP_AKA_CK_LEN);
  {
    u8 autn[EAP_AKA_AUTN_LEN];
    os_memset(autn, '1', EAP_AKA_AUTN_LEN);
    if (os_memcmp_const(autn, data->autn, EAP_AKA_AUTN_LEN) != 0) {
      wpa_printf(MSG_WARNING, "EAP-AKA: AUTN did not match "
           "with expected value");
      return -1;
    }
  }
#if 0
  {
    static int test_resync = 1;
    if (test_resync) {
      /* Test Resynchronization */
      test_resync = 0;
      return -2;
    }
  }
#endif
  return 0;

#else /* CONFIG_USIM_HARDCODED */

  wpa_printf(MSG_DEBUG, "EAP-AKA: No UMTS authentication algorithm "
       "enabled");
  return -1;

#endif /* CONFIG_USIM_HARDCODED */
}


#define CLEAR_PSEUDONYM 0x01
#define CLEAR_REAUTH_ID 0x02

static void eap_aka_clear_identities(struct eap_sm *sm,
             struct eap_aka_data *data, int id)
{
  if ((id & CLEAR_PSEUDONYM) && data->pseudonym) {
    wpa_printf(MSG_DEBUG, "EAP-AKA: forgetting old pseudonym");
    os_free(data->pseudonym);
    data->pseudonym = NULL;
    data->pseudonym_len = 0;
    if (data->use_pseudonym)
      eap_set_anon_id(sm, NULL, 0);
  }
  if ((id & CLEAR_REAUTH_ID) && data->reauth_id) {
    wpa_printf(MSG_DEBUG, "EAP-AKA: forgetting old reauth_id");
    os_free(data->reauth_id);
    data->reauth_id = NULL;
    data->reauth_id_len = 0;
  }
}


static int eap_aka_learn_ids(struct eap_sm *sm, struct eap_aka_data *data,
           struct eap_sim_attrs *attr)
{
  if (attr->next_pseudonym) {
    const u8 *identity = NULL;
    size_t identity_len = 0;
    const u8 *realm = NULL;
    size_t realm_len = 0;

    wpa_hexdump_ascii(MSG_DEBUG,
          "EAP-AKA: (encr) AT_NEXT_PSEUDONYM",
          attr->next_pseudonym,
          attr->next_pseudonym_len);
    os_free(data->pseudonym);
    /* Look for the realm of the permanent identity */
    identity = eap_get_config_identity(sm, &identity_len);
    if (identity) {
      for (realm = identity, realm_len = identity_len;
           realm_len > 0; realm_len--, realm++) {
        if (*realm == '@')
          break;
      }
    }
    data->pseudonym = os_malloc(attr->next_pseudonym_len +
              realm_len);
    if (data->pseudonym == NULL) {
      wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
           "next pseudonym");
      data->pseudonym_len = 0;
      return -1;
    }
    os_memcpy(data->pseudonym, attr->next_pseudonym,
        attr->next_pseudonym_len);
    if (realm_len) {
      os_memcpy(data->pseudonym + attr->next_pseudonym_len,
          realm, realm_len);
    }
    data->pseudonym_len = attr->next_pseudonym_len + realm_len;
    if (data->use_pseudonym)
      eap_set_anon_id(sm, data->pseudonym,
          data->pseudonym_len);
  }

  if (attr->next_reauth_id) {
    os_free(data->reauth_id);
    data->reauth_id = os_memdup(attr->next_reauth_id,
              attr->next_reauth_id_len);
    if (data->reauth_id == NULL) {
      wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
           "next reauth_id");
      data->reauth_id_len = 0;
      return -1;
    }
    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 int eap_aka_add_id_msg(struct eap_aka_data *data,
            const struct wpabuf *msg1,
            const struct wpabuf *msg2)
{
  size_t len;

  if (!msg1)
    return -1;
  len = wpabuf_len(msg1);
  if (msg2)
    len += wpabuf_len(msg2);

  if (!data->id_msgs) {
    data->id_msgs = wpabuf_alloc(len);
    if (!data->id_msgs)
      return -1;
  } else if (wpabuf_resize(&data->id_msgs, len) < 0) {
    return -1;
  }

  wpabuf_put_buf(data->id_msgs, msg1);
  if (msg2)
    wpabuf_put_buf(data->id_msgs, msg2);

  return 0;
}


static void eap_aka_add_checkcode(struct eap_aka_data *data,
          struct eap_sim_msg *msg)
{
  const u8 *addr;
  size_t len;
  u8 hash[SHA256_MAC_LEN];

  wpa_printf(MSG_DEBUG, "   AT_CHECKCODE");

  if (data->id_msgs == NULL) {
    /*
     * No EAP-AKA/Identity packets were exchanged - send empty
     * checkcode.
     */
    eap_sim_msg_add(msg, EAP_SIM_AT_CHECKCODE, 0, NULL, 0);
    return;
  }

  /* Checkcode is SHA1/SHA256 hash over all EAP-AKA/Identity packets. */
  addr = wpabuf_head(data->id_msgs);
  len = wpabuf_len(data->id_msgs);
  wpa_hexdump(MSG_MSGDUMP, "EAP-AKA: AT_CHECKCODE data", addr, len);
#ifdef EAP_AKA_PRIME
  if (data->eap_method == EAP_TYPE_AKA_PRIME)
    sha256_vector(1, &addr, &len, hash);
  else
#endif /* EAP_AKA_PRIME */
    sha1_vector(1, &addr, &len, hash);

  eap_sim_msg_add(msg, EAP_SIM_AT_CHECKCODE, 0, hash,
      data->eap_method == EAP_TYPE_AKA_PRIME ?
      EAP_AKA_PRIME_CHECKCODE_LEN : EAP_AKA_CHECKCODE_LEN);
}


static int eap_aka_verify_checkcode(struct eap_aka_data *data,
            const u8 *checkcode, size_t checkcode_len)
{
  const u8 *addr;
  size_t len;
  u8 hash[SHA256_MAC_LEN];
  size_t hash_len;

  if (checkcode == NULL)
    return -1;

  if (data->id_msgs == NULL) {
    if (checkcode_len != 0) {
      wpa_printf(MSG_DEBUG, "EAP-AKA: Checkcode from server "
           "indicates that AKA/Identity messages were "
           "used, but they were not");
      return -1;
    }
    return 0;
  }

  hash_len = data->eap_method == EAP_TYPE_AKA_PRIME ?
    EAP_AKA_PRIME_CHECKCODE_LEN : EAP_AKA_CHECKCODE_LEN;

  if (checkcode_len != hash_len) {
    wpa_printf(MSG_DEBUG, "EAP-AKA: Checkcode from server "
         "indicates that AKA/Identity message were not "
         "used, but they were");
    return -1;
  }

  /* Checkcode is SHA1/SHA256 hash over all EAP-AKA/Identity packets. */
  addr = wpabuf_head(data->id_msgs);
  len = wpabuf_len(data->id_msgs);
#ifdef EAP_AKA_PRIME
  if (data->eap_method == EAP_TYPE_AKA_PRIME)
    sha256_vector(1, &addr, &len, hash);
  else
#endif /* EAP_AKA_PRIME */
    sha1_vector(1, &addr, &len, hash);

  if (os_memcmp_const(hash, checkcode, hash_len) != 0) {
    wpa_printf(MSG_DEBUG, "EAP-AKA: Mismatch in AT_CHECKCODE");
    return -1;
  }

  return 0;
}


static struct wpabuf * eap_aka_client_error(struct eap_aka_data *data, u8 id,
              int err)
{
  struct eap_sim_msg *msg;

  eap_aka_state(data, FAILURE);
  data->num_id_req = 0;
  data->num_notification = 0;

  wpa_printf(MSG_DEBUG, "EAP-AKA: Send Client-Error (error code %d)",
       err);
  msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
             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, data->eap_method, NULL, NULL, 0);
}


static struct wpabuf * eap_aka_authentication_reject(struct eap_aka_data *data,
                 u8 id)
{
  struct eap_sim_msg *msg;

  eap_aka_state(data, FAILURE);
  data->num_id_req = 0;
  data->num_notification = 0;

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


static struct wpabuf * eap_aka_synchronization_failure(
  struct eap_aka_data *data, u8 id, struct eap_sim_attrs *attr)
{
  struct eap_sim_msg *msg;

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

  wpa_printf(MSG_DEBUG, "Generating EAP-AKA Synchronization-Failure "
       "(id=%d)", id);
  msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
             EAP_AKA_SUBTYPE_SYNCHRONIZATION_FAILURE);
  wpa_printf(MSG_DEBUG, "   AT_AUTS");
  eap_sim_msg_add_full(msg, EAP_SIM_AT_AUTS, data->auts,
           EAP_AKA_AUTS_LEN);
  if (data->eap_method == EAP_TYPE_AKA_PRIME) {
    size_t i;

    for (i = 0; i < attr->kdf_count; i++) {
      wpa_printf(MSG_DEBUG, "   AT_KDF");
      eap_sim_msg_add(msg, EAP_SIM_AT_KDF, attr->kdf[i],
          NULL, 0);
    }
  }
  return eap_sim_msg_finish(msg, data->eap_method, NULL, NULL, 0);
}


#ifdef CRYPTO_RSA_OAEP_SHA256
static struct wpabuf *
eap_aka_encrypt_identity(struct crypto_rsa_key *imsi_privacy_key,
       const u8 *identity, size_t identity_len,
       const char *attr)
{
  struct wpabuf *imsi_buf, *enc;
  char *b64;
  size_t b64_len, len;

  wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Encrypt permanent identity",
        identity, identity_len);

  imsi_buf = wpabuf_alloc_copy(identity, identity_len);
  if (!imsi_buf)
    return NULL;
  enc = crypto_rsa_oaep_sha256_encrypt(imsi_privacy_key, imsi_buf);
  wpabuf_free(imsi_buf);
  if (!enc)
    return NULL;

  b64 = base64_encode_no_lf(wpabuf_head(enc), wpabuf_len(enc), &b64_len);
  wpabuf_free(enc);
  if (!b64)
    return NULL;

  len = 1 + b64_len;
  if (attr)
    len += 1 + os_strlen(attr);
  enc = wpabuf_alloc(len);
  if (!enc) {
    os_free(b64);
    return NULL;
  }
  wpabuf_put_u8(enc, '\0');
  wpabuf_put_data(enc, b64, b64_len);
  os_free(b64);
  if (attr) {
    wpabuf_put_u8(enc, ',');
    wpabuf_put_str(enc, attr);
  }
  wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Encrypted permanent identity",
        wpabuf_head(enc), wpabuf_len(enc));

  return enc;
}
#endif /* CRYPTO_RSA_OAEP_SHA256 */


static struct wpabuf * eap_aka_response_identity(struct eap_sm *sm,
             struct eap_aka_data *data,
             u8 id,
             enum eap_sim_id_req id_req)
{
  const u8 *identity = NULL;
  size_t identity_len = 0;
  struct eap_sim_msg *msg;
  struct wpabuf *enc_identity = NULL;
  struct eap_peer_config *config = NULL;
  bool use_imsi_identity = false;

  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 &&
       !eap_sim_anonymous_username(data->pseudonym,
                 data->pseudonym_len)) {
    identity = data->pseudonym;
    identity_len = data->pseudonym_len;
    eap_aka_clear_identities(sm, data, CLEAR_REAUTH_ID);
  } else if (id_req != NO_ID_REQ) {
    identity = eap_get_config_identity(sm, &identity_len);
    if (identity) {
      int ids = CLEAR_PSEUDONYM | CLEAR_REAUTH_ID;

      if (data->pseudonym &&
          eap_sim_anonymous_username(data->pseudonym,
                   data->pseudonym_len))
        ids &= ~CLEAR_PSEUDONYM;
      eap_aka_clear_identities(sm, data, ids);

      config = eap_get_config(sm);
      if (config && config->imsi_identity)
        use_imsi_identity = true;
    }
#ifdef CRYPTO_RSA_OAEP_SHA256
    if (identity && data->imsi_privacy_key) {
      const char *attr = NULL;

      config = eap_get_config(sm);
      if (config)
        attr = config->imsi_privacy_attr;
      enc_identity = eap_aka_encrypt_identity(
        data->imsi_privacy_key,
        identity, identity_len, attr);
      if (!enc_identity) {
        wpa_printf(MSG_INFO,
             "EAP-AKA: Failed to encrypt permanent identity");
        return eap_aka_client_error(
          data, id,
          EAP_AKA_UNABLE_TO_PROCESS_PACKET);
      }
      /* Use the real identity, not the encrypted one, in MK
       * derivation. */
      os_free(data->mk_identity);
      data->mk_identity = os_memdup(identity, identity_len);
      data->mk_identity_len = identity_len;
      identity = wpabuf_head(enc_identity);
      identity_len = wpabuf_len(enc_identity);
    }
#endif /* CRYPTO_RSA_OAEP_SHA256 */
  }

  wpa_printf(MSG_DEBUG, "Generating EAP-AKA Identity (id=%d)", id);
  msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
             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);
    if (use_imsi_identity && config && config->imsi_identity) {
      /* Use the IMSI identity override, i.e., the not
       * encrypted one, in MK derivation, when using
       * externally encrypted identity in configuration. */
      os_free(data->mk_identity);
      data->mk_identity = os_memdup(
        config->imsi_identity,
        config->imsi_identity_len);
      data->mk_identity_len = config->imsi_identity_len;
    } else if (!enc_identity) {
      /* Use the last AT_IDENTITY value as the identity in
       * MK derivation. */
      os_free(data->mk_identity);
      data->mk_identity = os_memdup(identity, identity_len);
      data->mk_identity_len = identity_len;
    }
  }
  wpabuf_free(enc_identity);

  return eap_sim_msg_finish(msg, data->eap_method, NULL, NULL, 0);
}


static struct wpabuf * eap_aka_response_challenge(struct eap_aka_data *data,
              u8 id)
{
  struct eap_sim_msg *msg;

  wpa_printf(MSG_DEBUG, "Generating EAP-AKA Challenge (id=%d)", id);
  msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
             EAP_AKA_SUBTYPE_CHALLENGE);
  wpa_printf(MSG_DEBUG, "   AT_RES");
  eap_sim_msg_add(msg, EAP_SIM_AT_RES, data->res_len * 8,
      data->res, data->res_len);
  eap_aka_add_checkcode(data, msg);
  if (data->use_result_ind) {
    wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
    eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
  }
  wpa_printf(MSG_DEBUG, "   AT_MAC");
  eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
  return eap_sim_msg_finish(msg, data->eap_method, data->k_aut, (u8 *) "",
          0);
}


static struct wpabuf * eap_aka_response_reauth(struct eap_aka_data *data,
                 u8 id, int counter_too_small,
                 const u8 *nonce_s)
{
  struct eap_sim_msg *msg;
  unsigned int counter;

  wpa_printf(MSG_DEBUG, "Generating EAP-AKA Reauthentication (id=%d)",
       id);
  msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
             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;
  }
  eap_aka_add_checkcode(data, msg);
  if (data->use_result_ind) {
    wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
    eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
  }
  wpa_printf(MSG_DEBUG, "   AT_MAC");
  eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
  return eap_sim_msg_finish(msg, data->eap_method, data->k_aut, nonce_s,
          EAP_SIM_NONCE_S_LEN);
}


static struct wpabuf * eap_aka_response_notification(struct eap_aka_data *data,
                 u8 id, 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)", id);
  msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
             EAP_AKA_SUBTYPE_NOTIFICATION);
  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, data->eap_method, k_aut, (u8 *) "", 0);
}


static struct wpabuf * eap_aka_process_identity(struct eap_sm *sm,
            struct eap_aka_data *data,
            u8 id,
            const struct wpabuf *reqData,
            struct eap_sim_attrs *attr)
{
  int id_error;
  struct wpabuf *buf;

  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(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }

  buf = eap_aka_response_identity(sm, data, id, attr->id_req);

  if (data->prev_id != id) {
    if (eap_aka_add_id_msg(data, reqData, buf) < 0) {
      wpa_printf(MSG_INFO,
           "EAP-AKA: Failed to store ID messages");
      wpabuf_free(buf);
      return eap_aka_client_error(
        data, id, EAP_AKA_UNABLE_TO_PROCESS_PACKET);
    }
    data->prev_id = id;
  }

  return buf;
}


static int eap_aka_verify_mac(struct eap_aka_data *data,
            const struct wpabuf *req,
            const u8 *mac, const u8 *extra,
            size_t extra_len)
{
  if (data->eap_method == EAP_TYPE_AKA_PRIME)
    return eap_sim_verify_mac_sha256(data->k_aut, req, mac, extra,
             extra_len);
  return eap_sim_verify_mac(data->k_aut, req, mac, extra, extra_len);
}


#ifdef EAP_AKA_PRIME
static struct wpabuf * eap_aka_prime_kdf_select(struct eap_aka_data *data,
            u8 id, u16 kdf)
{
  struct eap_sim_msg *msg;

  data->kdf_negotiation = 1;
  data->kdf = kdf;
  wpa_printf(MSG_DEBUG, "Generating EAP-AKA Challenge (id=%d) (KDF "
       "select)", id);
  msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
             EAP_AKA_SUBTYPE_CHALLENGE);
  wpa_printf(MSG_DEBUG, "   AT_KDF");
  eap_sim_msg_add(msg, EAP_SIM_AT_KDF, kdf, NULL, 0);
  return eap_sim_msg_finish(msg, data->eap_method, NULL, NULL, 0);
}


static struct wpabuf * eap_aka_prime_kdf_neg(struct eap_aka_data *data,
               u8 id, struct eap_sim_attrs *attr)
{
  size_t i;

  for (i = 0; i < attr->kdf_count; i++) {
    if (attr->kdf[i] == EAP_AKA_PRIME_KDF) {
      os_memcpy(data->last_kdf_attrs, attr->kdf,
          sizeof(u16) * attr->kdf_count);
      data->last_kdf_count = attr->kdf_count;
      return eap_aka_prime_kdf_select(data, id,
              EAP_AKA_PRIME_KDF);
    }
  }

  /* No matching KDF found - fail authentication as if AUTN had been
   * incorrect */
  return eap_aka_authentication_reject(data, id);
}


static int eap_aka_prime_kdf_valid(struct eap_aka_data *data,
           struct eap_sim_attrs *attr)
{
  size_t i, j;

  if (attr->kdf_count == 0)
    return 0;

  /* The only allowed (and required) duplication of a KDF is the addition
   * of the selected KDF into the beginning of the list. */

  if (data->kdf_negotiation) {
    /* When the peer receives the new EAP-Request/AKA'-Challenge
     * message, must check only requested change occurred in the
     * list of AT_KDF attributes. If there are any other changes,
     * the peer must behave like the case that AT_MAC had been
     * incorrect and authentication is failed. These are defined in
     * EAP-AKA' specification RFC 5448, Section 3.2. */
    if (attr->kdf[0] != data->kdf) {
      wpa_printf(MSG_WARNING, "EAP-AKA': The server did not "
           "accept the selected KDF");
      return -1;
    }

    if (attr->kdf_count > EAP_AKA_PRIME_KDF_MAX ||
        attr->kdf_count != data->last_kdf_count + 1) {
      wpa_printf(MSG_WARNING,
           "EAP-AKA': The length of KDF attributes is wrong");
      return -1;
    }

    for (i = 1; i < attr->kdf_count; i++) {
      if (attr->kdf[i] != data->last_kdf_attrs[i - 1]) {
        wpa_printf(MSG_WARNING,
             "EAP-AKA': The KDF attributes except selected KDF are not same as original one");
        return -1;
      }
    }
  }

  for (i = data->kdf ? 1 : 0; i < attr->kdf_count; i++) {
    for (j = i + 1; j < attr->kdf_count; j++) {
      if (attr->kdf[i] == attr->kdf[j]) {
        wpa_printf(MSG_WARNING, "EAP-AKA': The server "
             "included a duplicated KDF");
        return 0;
      }
    }
  }

  return 1;
}
#endif /* EAP_AKA_PRIME */


static struct wpabuf * eap_aka_process_challenge(struct eap_sm *sm,
             struct eap_aka_data *data,
             u8 id,
             const struct wpabuf *reqData,
             struct eap_sim_attrs *attr)
{
  const u8 *identity;
  size_t identity_len;
  int res;
  struct eap_sim_attrs eattr;

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

  if (attr->checkcode &&
      eap_aka_verify_checkcode(data, attr->checkcode,
             attr->checkcode_len)) {
    wpa_printf(MSG_WARNING, "EAP-AKA: Invalid AT_CHECKCODE in the "
         "message");
#ifdef TEST_FUZZ
    wpa_printf(MSG_INFO,
         "TEST: Ignore AT_CHECKCODE mismatch for fuzz testing");
#else /* TEST_FUZZ */
    return eap_aka_client_error(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
#endif /* TEST_FUZZ */
  }

#ifdef EAP_AKA_PRIME
  if (data->eap_method == EAP_TYPE_AKA_PRIME) {
    if (!attr->kdf_input || attr->kdf_input_len == 0) {
      wpa_printf(MSG_WARNING, "EAP-AKA': Challenge message "
           "did not include non-empty AT_KDF_INPUT");
      /* Fail authentication as if AUTN had been incorrect */
      return eap_aka_authentication_reject(data, id);
    }
    os_free(data->network_name);
    data->network_name = os_memdup(attr->kdf_input,
                 attr->kdf_input_len);
    if (data->network_name == NULL) {
      wpa_printf(MSG_WARNING, "EAP-AKA': No memory for "
           "storing Network Name");
      return eap_aka_authentication_reject(data, id);
    }
    data->network_name_len = attr->kdf_input_len;
    wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA': Network Name "
          "(AT_KDF_INPUT)",
          data->network_name, data->network_name_len);
    /* TODO: check Network Name per 3GPP.33.402 */

    res = eap_aka_prime_kdf_valid(data, attr);
    if (res == 0)
      return eap_aka_authentication_reject(data, id);
    else if (res == -1)
      return eap_aka_client_error(
        data, id, EAP_AKA_UNABLE_TO_PROCESS_PACKET);

    if (attr->kdf[0] != EAP_AKA_PRIME_KDF)
      return eap_aka_prime_kdf_neg(data, id, attr);

    data->kdf = EAP_AKA_PRIME_KDF;
    wpa_printf(MSG_DEBUG, "EAP-AKA': KDF %d selected", data->kdf);
  }

  if (data->eap_method == EAP_TYPE_AKA && attr->bidding) {
    u16 flags = WPA_GET_BE16(attr->bidding);
    if ((flags & EAP_AKA_BIDDING_FLAG_D) &&
        eap_allowed_method(sm, EAP_VENDOR_IETF,
               EAP_TYPE_AKA_PRIME)) {
      wpa_printf(MSG_WARNING, "EAP-AKA: Bidding down from "
           "AKA' to AKA detected");
      /* Fail authentication as if AUTN had been incorrect */
      return eap_aka_authentication_reject(data, id);
    }
  }
#endif /* EAP_AKA_PRIME */

  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(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }
  os_memcpy(data->rand, attr->rand, EAP_AKA_RAND_LEN);
  os_memcpy(data->autn, attr->autn, EAP_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(data, id);
  } else if (res == -2) {
    wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication "
         "failed (AUTN seq# -> AUTS)");
    return eap_aka_synchronization_failure(data, id, attr);
  } else if (res > 0) {
    wpa_printf(MSG_DEBUG, "EAP-AKA: Wait for external USIM processing");
    return NULL;
  } else if (res) {
    wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication failed");
    return eap_aka_client_error(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }
#ifdef EAP_AKA_PRIME
  if (data->eap_method == EAP_TYPE_AKA_PRIME) {
    /* Note: AUTN = (SQN ^ AK) || AMF || MAC which gives us the
     * needed 6-octet SQN ^ AK for CK',IK' derivation */
    u16 amf = WPA_GET_BE16(data->autn + 6);
    if (!(amf & 0x8000)) {
      wpa_printf(MSG_WARNING, "EAP-AKA': AMF separation bit "
           "not set (AMF=0x%4x)", amf);
      return eap_aka_authentication_reject(data, id);
    }
    eap_aka_prime_derive_ck_ik_prime(data->ck, data->ik,
             data->autn,
             data->network_name,
             data->network_name_len);
  }
#endif /* EAP_AKA_PRIME */

  identity = data->mk_identity;
  identity_len = data->mk_identity_len;
  wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Selected identity for MK "
        "derivation", identity, identity_len);
  if (data->eap_method == EAP_TYPE_AKA_PRIME) {
    eap_aka_prime_derive_keys(identity, identity_len, data->ik,
            data->ck, data->k_encr, data->k_aut,
            data->k_re, data->msk, data->emsk);
  } else {
    eap_aka_derive_mk(identity, identity_len, data->ik, data->ck,
          data->mk);
    eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut,
            data->msk, data->emsk);
  }
  if (eap_aka_verify_mac(data, reqData, attr->mac, (u8 *) "", 0)) {
    wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
         "used invalid AT_MAC");
#ifdef TEST_FUZZ
    wpa_printf(MSG_INFO,
         "TEST: Ignore AT_MAC mismatch for fuzz testing");
#else /* TEST_FUZZ */
    return eap_aka_client_error(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
#endif /* TEST_FUZZ */
  }

  /* Old reauthentication identity must not be used anymore. In
   * other words, if no new identities are received, full
   * authentication will be used on next reauthentication (using
   * pseudonym identity or permanent identity). */
  eap_aka_clear_identities(sm, data, CLEAR_REAUTH_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(
        data, id, EAP_AKA_UNABLE_TO_PROCESS_PACKET);
    }
    eap_aka_learn_ids(sm, data, &eattr);
    os_free(decrypted);
  }

  if (data->result_ind && attr->result_ind)
    data->use_result_ind = 1;

  if (data->state != FAILURE) {
    eap_aka_state(data, data->use_result_ind ?
            RESULT_SUCCESS : SUCCESS);
  }

  data->num_id_req = 0;
  data->num_notification = 0;
  /* RFC 4187 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(data, id);
}


static int eap_aka_process_notification_reauth(struct eap_aka_data *data,
                 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 < 0 || (size_t) eattr.counter != data->counter) {
    wpa_printf(MSG_WARNING, "EAP-AKA: Counter in notification "
         "message does not match with counter in reauth "
         "message");
    os_free(decrypted);
    return -1;
  }

  os_free(decrypted);
  return 0;
}


static int eap_aka_process_notification_auth(struct eap_aka_data *data,
               const struct wpabuf *reqData,
               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_aka_verify_mac(data, reqData, 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, attr)) {
    wpa_printf(MSG_WARNING, "EAP-AKA: Invalid notification "
         "message after reauth");
    return -1;
  }

  return 0;
}


static struct wpabuf * eap_aka_process_notification(
  struct eap_sm *sm, struct eap_aka_data *data, u8 id,
  const struct wpabuf *reqData, 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(data, id,
              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(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }

  if ((attr->notification & 0x4000) == 0 &&
      eap_aka_process_notification_auth(data, reqData, attr)) {
    return eap_aka_client_error(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }

  eap_sim_report_notification(sm->msg_ctx, attr->notification, 1);
  if (attr->notification >= 0 && attr->notification < 32768) {
    data->error_code = attr->notification;
    eap_aka_state(data, FAILURE);
  } else if (attr->notification == EAP_SIM_SUCCESS &&
       data->state == RESULT_SUCCESS)
    eap_aka_state(data, SUCCESS);
  return eap_aka_response_notification(data, id, attr->notification);
}


static struct wpabuf * eap_aka_process_reauthentication(
  struct eap_sm *sm, struct eap_aka_data *data, u8 id,
  const struct wpabuf *reqData, struct eap_sim_attrs *attr)
{
  struct eap_sim_attrs eattr;
  u8 *decrypted;

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

  if (attr->checkcode &&
      eap_aka_verify_checkcode(data, attr->checkcode,
             attr->checkcode_len)) {
#ifdef TEST_FUZZ
    wpa_printf(MSG_INFO,
         "TEST: Ignore AT_CHECKCODE mismatch for fuzz testing");
#else /* TEST_FUZZ */
    wpa_printf(MSG_WARNING, "EAP-AKA: Invalid AT_CHECKCODE in the "
         "message");
#endif /* TEST_FUZZ */
    return eap_aka_client_error(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }

  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(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }

  data->reauth = 1;
  if (eap_aka_verify_mac(data, reqData, attr->mac, (u8 *) "", 0)) {
    wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
         "did not have valid AT_MAC");
    return eap_aka_client_error(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }

  /* At this stage the received MAC has been verified. Use this MAC for
   * reauth Session-Id calculation if all other checks pass.
   * The peer does not use the local MAC but the received MAC in deriving
   * Session-Id. */
  os_memcpy(data->reauth_mac, attr->mac, EAP_SIM_MAC_LEN);
  wpa_hexdump(MSG_DEBUG, "EAP-AKA: Server MAC",
        data->reauth_mac, EAP_SIM_MAC_LEN);

  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(data, id,
              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(data, id,
              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" : "");
    os_free(decrypted);
    return eap_aka_client_error(data, id,
              EAP_AKA_UNABLE_TO_PROCESS_PACKET);
  }

  if (eattr.counter < 0 || (size_t) eattr.counter <= data->counter) {
    struct wpabuf *res;
    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.
     */
    eap_aka_clear_identities(sm, data, CLEAR_REAUTH_ID);

    res = eap_aka_response_reauth(data, id, 1, eattr.nonce_s);
    os_free(decrypted);

    return res;
  }
  data->counter = eattr.counter;

  os_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);

  if (data->eap_method == EAP_TYPE_AKA_PRIME) {
    eap_aka_prime_derive_keys_reauth(data->k_re, data->counter,
             data->reauth_id,
             data->reauth_id_len,
             data->nonce_s,
             data->msk, data->emsk);
  } else {
    eap_sim_derive_keys_reauth(data->counter, data->reauth_id,
             data->reauth_id_len,
             data->nonce_s, data->mk,
             data->msk, data->emsk);
  }
  eap_aka_clear_identities(sm, data, CLEAR_REAUTH_ID);
  eap_aka_learn_ids(sm, data, &eattr);

  if (data->result_ind && attr->result_ind)
    data->use_result_ind = 1;

  if (data->state != FAILURE) {
    eap_aka_state(data, data->use_result_ind ?
            RESULT_SUCCESS : 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(sm, data, CLEAR_REAUTH_ID);
  }
  os_free(decrypted);
  return eap_aka_response_reauth(data, id, 0, data->nonce_s);
}


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

  wpa_hexdump_buf(MSG_DEBUG, "EAP-AKA: EAP data", reqData);
  if (eap_get_config_identity(sm, &len) == NULL) {
    wpa_printf(MSG_INFO, "EAP-AKA: Identity not configured");
    eap_sm_request_identity(sm);
    ret->ignore = true;
    return NULL;
  }

  pos = eap_hdr_validate(EAP_VENDOR_IETF, data->eap_method, reqData,
             &len);
  if (pos == NULL || len < 3) {
    ret->ignore = true;
    return NULL;
  }
  req = wpabuf_head(reqData);
  id = req->identifier;
  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, wpabuf_head_u8(reqData) + len, &attr,
             data->eap_method == EAP_TYPE_AKA_PRIME ? 2 : 1,
             0)) {
    res = eap_aka_client_error(data, id,
             EAP_AKA_UNABLE_TO_PROCESS_PACKET);
    goto done;
  }

  switch (subtype) {
  case EAP_AKA_SUBTYPE_IDENTITY:
    res = eap_aka_process_identity(sm, data, id, reqData, &attr);
    break;
  case EAP_AKA_SUBTYPE_CHALLENGE:
    res = eap_aka_process_challenge(sm, data, id, reqData, &attr);
    break;
  case EAP_AKA_SUBTYPE_NOTIFICATION:
    res = eap_aka_process_notification(sm, data, id, reqData,
               &attr);
    break;
  case EAP_AKA_SUBTYPE_REAUTHENTICATION:
    res = eap_aka_process_reauthentication(sm, data, id, reqData,
                   &attr);
    break;
  case EAP_AKA_SUBTYPE_CLIENT_ERROR:
    wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Client-Error");
    res = eap_aka_client_error(data, id,
             EAP_AKA_UNABLE_TO_PROCESS_PACKET);
    break;
  default:
    wpa_printf(MSG_DEBUG, "EAP-AKA: Unknown subtype=%d", subtype);
    res = eap_aka_client_error(data, id,
             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 = data->use_result_ind ?
      DECISION_UNCOND_SUCC : DECISION_COND_SUCC;
    /*
     * It is possible for the server to reply with AKA
     * Notification, so we must allow the method to continue and
     * not only accept EAP-Success at this point.
     */
    ret->methodState = data->use_result_ind ?
      METHOD_DONE : METHOD_MAY_CONT;
  } else if (data->state == RESULT_SUCCESS)
    ret->methodState = METHOD_CONT;

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

  return res;
}


static bool 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;

  os_free(data->mk_identity);
  data->mk_identity = NULL;
  data->mk_identity_len = 0;
  data->prev_id = -1;
  wpabuf_free(data->id_msgs);
  data->id_msgs = NULL;
  data->use_result_ind = 0;
  data->kdf_negotiation = 0;
  eap_aka_clear_keys(data, 1);
}


static void * eap_aka_init_for_reauth(struct eap_sm *sm, void *priv)
{
  struct eap_aka_data *data = priv;

  if (sm->identity) {
    /* Use the EAP-Response/Identity in MK derivation if AT_IDENTITY
     * is not used. */
    os_free(data->mk_identity);
    data->mk_identity = os_memdup(sm->identity, sm->identity_len);
    data->mk_identity_len = sm->identity_len;
  }

  data->num_id_req = 0;
  data->num_notification = 0;
  eap_aka_state(data, 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 bool 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 = os_memdup(data->msk, EAP_SIM_KEYING_DATA_LEN);
  if (key == NULL)
    return NULL;

  *len = EAP_SIM_KEYING_DATA_LEN;

  return key;
}


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

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

  if (!data->reauth)
    *len = 1 + EAP_AKA_RAND_LEN + EAP_AKA_AUTN_LEN;
  else
    *len = 1 + EAP_SIM_NONCE_S_LEN + EAP_SIM_MAC_LEN;
  id = os_malloc(*len);
  if (id == NULL)
    return NULL;

  id[0] = data->eap_method;
  if (!data->reauth) {
    os_memcpy(id + 1, data->rand, EAP_AKA_RAND_LEN);
    os_memcpy(id + 1 + EAP_AKA_RAND_LEN, data->autn,
        EAP_AKA_AUTN_LEN);
  } else {
    os_memcpy(id + 1, data->nonce_s, EAP_SIM_NONCE_S_LEN);
    os_memcpy(id + 1 + EAP_SIM_NONCE_S_LEN, data->reauth_mac,
        EAP_SIM_MAC_LEN);
  }
  wpa_hexdump(MSG_DEBUG, "EAP-AKA: Derived Session-Id", id, *len);

  return id;
}


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

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

  key = os_memdup(data->emsk, EAP_EMSK_LEN);
  if (key == NULL)
    return NULL;

  *len = EAP_EMSK_LEN;

  return key;
}


static int eap_aka_get_error_code(void *priv)
{
  struct eap_aka_data *data = priv;
  int current_data_error;

  if (!data)
    return NO_EAP_METHOD_ERROR;

  current_data_error = data->error_code;

  /* Now reset for next transaction */
  data->error_code = NO_EAP_METHOD_ERROR;

  return current_data_error;
}


int eap_peer_aka_register(void)
{
  struct eap_method *eap;

  eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
            EAP_VENDOR_IETF, EAP_TYPE_AKA, "AKA");
  if (eap == NULL)
    return -1;

  eap->init = eap_aka_init;
  eap->deinit = eap_aka_deinit;
  eap->process = eap_aka_process;
  eap->isKeyAvailable = eap_aka_isKeyAvailable;
  eap->getKey = eap_aka_getKey;
  eap->getSessionId = eap_aka_get_session_id;
  eap->has_reauth_data = eap_aka_has_reauth_data;
  eap->deinit_for_reauth = eap_aka_deinit_for_reauth;
  eap->init_for_reauth = eap_aka_init_for_reauth;
  eap->get_identity = eap_aka_get_identity;
  eap->get_emsk = eap_aka_get_emsk;
  eap->get_error_code = eap_aka_get_error_code;

  return eap_peer_method_register(eap);
}


#ifdef EAP_AKA_PRIME
int eap_peer_aka_prime_register(void)
{
  struct eap_method *eap;

  eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
            EAP_VENDOR_IETF, EAP_TYPE_AKA_PRIME,
            "AKA'");
  if (eap == NULL)
    return -1;

  eap->init = eap_aka_prime_init;
  eap->deinit = eap_aka_deinit;
  eap->process = eap_aka_process;
  eap->isKeyAvailable = eap_aka_isKeyAvailable;
  eap->getKey = eap_aka_getKey;
  eap->getSessionId = eap_aka_get_session_id;
  eap->has_reauth_data = eap_aka_has_reauth_data;
  eap->deinit_for_reauth = eap_aka_deinit_for_reauth;
  eap->init_for_reauth = eap_aka_init_for_reauth;
  eap->get_identity = eap_aka_get_identity;
  eap->get_emsk = eap_aka_get_emsk;
  eap->get_error_code = eap_aka_get_error_code;

  return eap_peer_method_register(eap);
}
#endif /* EAP_AKA_PRIME */

Coverage Report

Created: 2025-04-24 06:18