Merged the hostap_2.6 updates, and the Leap of Faith work, from the hostap_update...
[mech_eap.git] / libeap / src / eap_common / eap_eke_common.c
diff --git a/libeap/src/eap_common/eap_eke_common.c b/libeap/src/eap_common/eap_eke_common.c
new file mode 100644 (file)
index 0000000..6217468
--- /dev/null
@@ -0,0 +1,750 @@
+/*
+ * EAP server/peer: EAP-EKE shared routines
+ * Copyright (c) 2011-2013, 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 "crypto/aes.h"
+#include "crypto/aes_wrap.h"
+#include "crypto/crypto.h"
+#include "crypto/dh_groups.h"
+#include "crypto/random.h"
+#include "crypto/sha1.h"
+#include "crypto/sha256.h"
+#include "eap_common/eap_defs.h"
+#include "eap_eke_common.h"
+
+
+static int eap_eke_dh_len(u8 group)
+{
+       switch (group) {
+       case EAP_EKE_DHGROUP_EKE_2:
+               return 128;
+       case EAP_EKE_DHGROUP_EKE_5:
+               return 192;
+       case EAP_EKE_DHGROUP_EKE_14:
+               return 256;
+       case EAP_EKE_DHGROUP_EKE_15:
+               return 384;
+       case EAP_EKE_DHGROUP_EKE_16:
+               return 512;
+       }
+
+       return -1;
+}
+
+
+static int eap_eke_dhcomp_len(u8 dhgroup, u8 encr)
+{
+       int dhlen;
+
+       dhlen = eap_eke_dh_len(dhgroup);
+       if (dhlen < 0 || encr != EAP_EKE_ENCR_AES128_CBC)
+               return -1;
+       return AES_BLOCK_SIZE + dhlen;
+}
+
+
+static const struct dh_group * eap_eke_dh_group(u8 group)
+{
+       switch (group) {
+       case EAP_EKE_DHGROUP_EKE_2:
+               return dh_groups_get(2);
+       case EAP_EKE_DHGROUP_EKE_5:
+               return dh_groups_get(5);
+       case EAP_EKE_DHGROUP_EKE_14:
+               return dh_groups_get(14);
+       case EAP_EKE_DHGROUP_EKE_15:
+               return dh_groups_get(15);
+       case EAP_EKE_DHGROUP_EKE_16:
+               return dh_groups_get(16);
+       }
+
+       return NULL;
+}
+
+
+static int eap_eke_dh_generator(u8 group)
+{
+       switch (group) {
+       case EAP_EKE_DHGROUP_EKE_2:
+               return 5;
+       case EAP_EKE_DHGROUP_EKE_5:
+               return 31;
+       case EAP_EKE_DHGROUP_EKE_14:
+               return 11;
+       case EAP_EKE_DHGROUP_EKE_15:
+               return 5;
+       case EAP_EKE_DHGROUP_EKE_16:
+               return 5;
+       }
+
+       return -1;
+}
+
+
+static int eap_eke_pnonce_len(u8 mac)
+{
+       int mac_len;
+
+       if (mac == EAP_EKE_MAC_HMAC_SHA1)
+               mac_len = SHA1_MAC_LEN;
+       else if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
+               mac_len = SHA256_MAC_LEN;
+       else
+               return -1;
+
+       return AES_BLOCK_SIZE + 16 + mac_len;
+}
+
+
+static int eap_eke_pnonce_ps_len(u8 mac)
+{
+       int mac_len;
+
+       if (mac == EAP_EKE_MAC_HMAC_SHA1)
+               mac_len = SHA1_MAC_LEN;
+       else if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
+               mac_len = SHA256_MAC_LEN;
+       else
+               return -1;
+
+       return AES_BLOCK_SIZE + 2 * 16 + mac_len;
+}
+
+
+static int eap_eke_prf_len(u8 prf)
+{
+       if (prf == EAP_EKE_PRF_HMAC_SHA1)
+               return 20;
+       if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
+               return 32;
+       return -1;
+}
+
+
+static int eap_eke_nonce_len(u8 prf)
+{
+       int prf_len;
+
+       prf_len = eap_eke_prf_len(prf);
+       if (prf_len < 0)
+               return -1;
+
+       if (prf_len > 2 * 16)
+               return (prf_len + 1) / 2;
+
+       return 16;
+}
+
+
+static int eap_eke_auth_len(u8 prf)
+{
+       switch (prf) {
+       case EAP_EKE_PRF_HMAC_SHA1:
+               return SHA1_MAC_LEN;
+       case EAP_EKE_PRF_HMAC_SHA2_256:
+               return SHA256_MAC_LEN;
+       }
+
+       return -1;
+}
+
+
+int eap_eke_dh_init(u8 group, u8 *ret_priv, u8 *ret_pub)
+{
+       int generator;
+       u8 gen;
+       const struct dh_group *dh;
+       size_t pub_len, i;
+
+       generator = eap_eke_dh_generator(group);
+       dh = eap_eke_dh_group(group);
+       if (generator < 0 || generator > 255 || !dh)
+               return -1;
+       gen = generator;
+
+       /* x = random number 2 .. p-1 */
+       if (random_get_bytes(ret_priv, dh->prime_len))
+               return -1;
+       if (os_memcmp(ret_priv, dh->prime, dh->prime_len) > 0) {
+               /* Make sure private value is smaller than prime */
+               ret_priv[0] = 0;
+       }
+       for (i = 0; i < dh->prime_len - 1; i++) {
+               if (ret_priv[i])
+                       break;
+       }
+       if (i == dh->prime_len - 1 && (ret_priv[i] == 0 || ret_priv[i] == 1))
+               return -1;
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: DH private value",
+                       ret_priv, dh->prime_len);
+
+       /* y = g ^ x (mod p) */
+       pub_len = dh->prime_len;
+       if (crypto_mod_exp(&gen, 1, ret_priv, dh->prime_len,
+                          dh->prime, dh->prime_len, ret_pub, &pub_len) < 0)
+               return -1;
+       if (pub_len < dh->prime_len) {
+               size_t pad = dh->prime_len - pub_len;
+               os_memmove(ret_pub + pad, ret_pub, pub_len);
+               os_memset(ret_pub, 0, pad);
+       }
+
+       wpa_hexdump(MSG_DEBUG, "EAP-EKE: DH public value",
+                   ret_pub, dh->prime_len);
+
+       return 0;
+}
+
+
+static int eap_eke_prf(u8 prf, const u8 *key, size_t key_len, const u8 *data,
+                      size_t data_len, const u8 *data2, size_t data2_len,
+                      u8 *res)
+{
+       const u8 *addr[2];
+       size_t len[2];
+       size_t num_elem = 1;
+
+       addr[0] = data;
+       len[0] = data_len;
+       if (data2) {
+               num_elem++;
+               addr[1] = data2;
+               len[1] = data2_len;
+       }
+
+       if (prf == EAP_EKE_PRF_HMAC_SHA1)
+               return hmac_sha1_vector(key, key_len, num_elem, addr, len, res);
+       if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
+               return hmac_sha256_vector(key, key_len, num_elem, addr, len,
+                                         res);
+       return -1;
+}
+
+
+static int eap_eke_prf_hmac_sha1(const u8 *key, size_t key_len, const u8 *data,
+                                size_t data_len, u8 *res, size_t len)
+{
+       u8 hash[SHA1_MAC_LEN];
+       u8 idx;
+       const u8 *addr[3];
+       size_t vlen[3];
+       int ret;
+
+       idx = 0;
+       addr[0] = hash;
+       vlen[0] = SHA1_MAC_LEN;
+       addr[1] = data;
+       vlen[1] = data_len;
+       addr[2] = &idx;
+       vlen[2] = 1;
+
+       while (len > 0) {
+               idx++;
+               if (idx == 1)
+                       ret = hmac_sha1_vector(key, key_len, 2, &addr[1],
+                                              &vlen[1], hash);
+               else
+                       ret = hmac_sha1_vector(key, key_len, 3, addr, vlen,
+                                              hash);
+               if (ret < 0)
+                       return -1;
+               if (len > SHA1_MAC_LEN) {
+                       os_memcpy(res, hash, SHA1_MAC_LEN);
+                       res += SHA1_MAC_LEN;
+                       len -= SHA1_MAC_LEN;
+               } else {
+                       os_memcpy(res, hash, len);
+                       len = 0;
+               }
+       }
+
+       return 0;
+}
+
+
+static int eap_eke_prf_hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
+                                  size_t data_len, u8 *res, size_t len)
+{
+       u8 hash[SHA256_MAC_LEN];
+       u8 idx;
+       const u8 *addr[3];
+       size_t vlen[3];
+       int ret;
+
+       idx = 0;
+       addr[0] = hash;
+       vlen[0] = SHA256_MAC_LEN;
+       addr[1] = data;
+       vlen[1] = data_len;
+       addr[2] = &idx;
+       vlen[2] = 1;
+
+       while (len > 0) {
+               idx++;
+               if (idx == 1)
+                       ret = hmac_sha256_vector(key, key_len, 2, &addr[1],
+                                                &vlen[1], hash);
+               else
+                       ret = hmac_sha256_vector(key, key_len, 3, addr, vlen,
+                                                hash);
+               if (ret < 0)
+                       return -1;
+               if (len > SHA256_MAC_LEN) {
+                       os_memcpy(res, hash, SHA256_MAC_LEN);
+                       res += SHA256_MAC_LEN;
+                       len -= SHA256_MAC_LEN;
+               } else {
+                       os_memcpy(res, hash, len);
+                       len = 0;
+               }
+       }
+
+       return 0;
+}
+
+
+static int eap_eke_prfplus(u8 prf, const u8 *key, size_t key_len,
+                          const u8 *data, size_t data_len, u8 *res, size_t len)
+{
+       if (prf == EAP_EKE_PRF_HMAC_SHA1)
+               return eap_eke_prf_hmac_sha1(key, key_len, data, data_len, res,
+                                            len);
+       if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
+               return eap_eke_prf_hmac_sha256(key, key_len, data, data_len,
+                                              res, len);
+       return -1;
+}
+
+
+int eap_eke_derive_key(struct eap_eke_session *sess,
+                      const u8 *password, size_t password_len,
+                      const u8 *id_s, size_t id_s_len, const u8 *id_p,
+                      size_t id_p_len, u8 *key)
+{
+       u8 zeros[EAP_EKE_MAX_HASH_LEN];
+       u8 temp[EAP_EKE_MAX_HASH_LEN];
+       size_t key_len = 16; /* Only AES-128-CBC is used here */
+       u8 *id;
+
+       /* temp = prf(0+, password) */
+       os_memset(zeros, 0, sess->prf_len);
+       if (eap_eke_prf(sess->prf, zeros, sess->prf_len,
+                       password, password_len, NULL, 0, temp) < 0)
+               return -1;
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: temp = prf(0+, password)",
+                       temp, sess->prf_len);
+
+       /* key = prf+(temp, ID_S | ID_P) */
+       id = os_malloc(id_s_len + id_p_len);
+       if (id == NULL)
+               return -1;
+       os_memcpy(id, id_s, id_s_len);
+       os_memcpy(id + id_s_len, id_p, id_p_len);
+       wpa_hexdump_ascii(MSG_DEBUG, "EAP-EKE: ID_S | ID_P",
+                         id, id_s_len + id_p_len);
+       if (eap_eke_prfplus(sess->prf, temp, sess->prf_len,
+                           id, id_s_len + id_p_len, key, key_len) < 0) {
+               os_free(id);
+               return -1;
+       }
+       os_free(id);
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: key = prf+(temp, ID_S | ID_P)",
+                       key, key_len);
+
+       return 0;
+}
+
+
+int eap_eke_dhcomp(struct eap_eke_session *sess, const u8 *key, const u8 *dhpub,
+                  u8 *ret_dhcomp)
+{
+       u8 pub[EAP_EKE_MAX_DH_LEN];
+       int dh_len;
+       u8 iv[AES_BLOCK_SIZE];
+
+       dh_len = eap_eke_dh_len(sess->dhgroup);
+       if (dh_len < 0)
+               return -1;
+
+       /*
+        * DHComponent = Encr(key, y)
+        *
+        * All defined DH groups use primes that have length devisible by 16, so
+        * no need to do extra padding for y (= pub).
+        */
+       if (sess->encr != EAP_EKE_ENCR_AES128_CBC)
+               return -1;
+       if (random_get_bytes(iv, AES_BLOCK_SIZE))
+               return -1;
+       wpa_hexdump(MSG_DEBUG, "EAP-EKE: IV for Encr(key, y)",
+                   iv, AES_BLOCK_SIZE);
+       os_memcpy(pub, dhpub, dh_len);
+       if (aes_128_cbc_encrypt(key, iv, pub, dh_len) < 0)
+               return -1;
+       os_memcpy(ret_dhcomp, iv, AES_BLOCK_SIZE);
+       os_memcpy(ret_dhcomp + AES_BLOCK_SIZE, pub, dh_len);
+       wpa_hexdump(MSG_DEBUG, "EAP-EKE: DHComponent = Encr(key, y)",
+                   ret_dhcomp, AES_BLOCK_SIZE + dh_len);
+
+       return 0;
+}
+
+
+int eap_eke_shared_secret(struct eap_eke_session *sess, const u8 *key,
+                         const u8 *dhpriv, const u8 *peer_dhcomp)
+{
+       u8 zeros[EAP_EKE_MAX_HASH_LEN];
+       u8 peer_pub[EAP_EKE_MAX_DH_LEN];
+       u8 modexp[EAP_EKE_MAX_DH_LEN];
+       size_t len;
+       const struct dh_group *dh;
+
+       dh = eap_eke_dh_group(sess->dhgroup);
+       if (sess->encr != EAP_EKE_ENCR_AES128_CBC || !dh)
+               return -1;
+
+       /* Decrypt peer DHComponent */
+       os_memcpy(peer_pub, peer_dhcomp + AES_BLOCK_SIZE, dh->prime_len);
+       if (aes_128_cbc_decrypt(key, peer_dhcomp, peer_pub, dh->prime_len) < 0) {
+               wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt DHComponent");
+               return -1;
+       }
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Decrypted peer DH pubkey",
+                       peer_pub, dh->prime_len);
+
+       /* SharedSecret = prf(0+, g ^ (x_s * x_p) (mod p)) */
+       len = dh->prime_len;
+       if (crypto_mod_exp(peer_pub, dh->prime_len, dhpriv, dh->prime_len,
+                          dh->prime, dh->prime_len, modexp, &len) < 0)
+               return -1;
+       if (len < dh->prime_len) {
+               size_t pad = dh->prime_len - len;
+               os_memmove(modexp + pad, modexp, len);
+               os_memset(modexp, 0, pad);
+       }
+
+       os_memset(zeros, 0, sess->auth_len);
+       if (eap_eke_prf(sess->prf, zeros, sess->auth_len, modexp, dh->prime_len,
+                       NULL, 0, sess->shared_secret) < 0)
+               return -1;
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: SharedSecret",
+                       sess->shared_secret, sess->auth_len);
+
+       return 0;
+}
+
+
+int eap_eke_derive_ke_ki(struct eap_eke_session *sess,
+                        const u8 *id_s, size_t id_s_len,
+                        const u8 *id_p, size_t id_p_len)
+{
+       u8 buf[EAP_EKE_MAX_KE_LEN + EAP_EKE_MAX_KI_LEN];
+       size_t ke_len, ki_len;
+       u8 *data;
+       size_t data_len;
+       const char *label = "EAP-EKE Keys";
+       size_t label_len;
+
+       /*
+        * Ke | Ki = prf+(SharedSecret, "EAP-EKE Keys" | ID_S | ID_P)
+        * Ke = encryption key
+        * Ki = integrity protection key
+        * Length of each key depends on the selected algorithms.
+        */
+
+       if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
+               ke_len = 16;
+       else
+               return -1;
+
+       if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
+               ki_len = 20;
+       else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
+               ki_len = 32;
+       else
+               return -1;
+
+       label_len = os_strlen(label);
+       data_len = label_len + id_s_len + id_p_len;
+       data = os_malloc(data_len);
+       if (data == NULL)
+               return -1;
+       os_memcpy(data, label, label_len);
+       os_memcpy(data + label_len, id_s, id_s_len);
+       os_memcpy(data + label_len + id_s_len, id_p, id_p_len);
+       if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
+                           data, data_len, buf, ke_len + ki_len) < 0) {
+               os_free(data);
+               return -1;
+       }
+
+       os_memcpy(sess->ke, buf, ke_len);
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ke", sess->ke, ke_len);
+       os_memcpy(sess->ki, buf + ke_len, ki_len);
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ki", sess->ki, ki_len);
+
+       os_free(data);
+       return 0;
+}
+
+
+int eap_eke_derive_ka(struct eap_eke_session *sess,
+                     const u8 *id_s, size_t id_s_len,
+                     const u8 *id_p, size_t id_p_len,
+                     const u8 *nonce_p, const u8 *nonce_s)
+{
+       u8 *data, *pos;
+       size_t data_len;
+       const char *label = "EAP-EKE Ka";
+       size_t label_len;
+
+       /*
+        * Ka = prf+(SharedSecret, "EAP-EKE Ka" | ID_S | ID_P | Nonce_P |
+        *           Nonce_S)
+        * Ka = authentication key
+        * Length of the key depends on the selected algorithms.
+        */
+
+       label_len = os_strlen(label);
+       data_len = label_len + id_s_len + id_p_len + 2 * sess->nonce_len;
+       data = os_malloc(data_len);
+       if (data == NULL)
+               return -1;
+       pos = data;
+       os_memcpy(pos, label, label_len);
+       pos += label_len;
+       os_memcpy(pos, id_s, id_s_len);
+       pos += id_s_len;
+       os_memcpy(pos, id_p, id_p_len);
+       pos += id_p_len;
+       os_memcpy(pos, nonce_p, sess->nonce_len);
+       pos += sess->nonce_len;
+       os_memcpy(pos, nonce_s, sess->nonce_len);
+       if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
+                           data, data_len, sess->ka, sess->prf_len) < 0) {
+               os_free(data);
+               return -1;
+       }
+       os_free(data);
+
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ka", sess->ka, sess->prf_len);
+
+       return 0;
+}
+
+
+int eap_eke_derive_msk(struct eap_eke_session *sess,
+                      const u8 *id_s, size_t id_s_len,
+                      const u8 *id_p, size_t id_p_len,
+                      const u8 *nonce_p, const u8 *nonce_s,
+                      u8 *msk, u8 *emsk)
+{
+       u8 *data, *pos;
+       size_t data_len;
+       const char *label = "EAP-EKE Exported Keys";
+       size_t label_len;
+       u8 buf[EAP_MSK_LEN + EAP_EMSK_LEN];
+
+       /*
+        * MSK | EMSK = prf+(SharedSecret, "EAP-EKE Exported Keys" | ID_S |
+        *                   ID_P | Nonce_P | Nonce_S)
+        */
+
+       label_len = os_strlen(label);
+       data_len = label_len + id_s_len + id_p_len + 2 * sess->nonce_len;
+       data = os_malloc(data_len);
+       if (data == NULL)
+               return -1;
+       pos = data;
+       os_memcpy(pos, label, label_len);
+       pos += label_len;
+       os_memcpy(pos, id_s, id_s_len);
+       pos += id_s_len;
+       os_memcpy(pos, id_p, id_p_len);
+       pos += id_p_len;
+       os_memcpy(pos, nonce_p, sess->nonce_len);
+       pos += sess->nonce_len;
+       os_memcpy(pos, nonce_s, sess->nonce_len);
+       if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
+                           data, data_len, buf, EAP_MSK_LEN + EAP_EMSK_LEN) <
+           0) {
+               os_free(data);
+               return -1;
+       }
+       os_free(data);
+
+       os_memcpy(msk, buf, EAP_MSK_LEN);
+       os_memcpy(emsk, buf + EAP_MSK_LEN, EAP_EMSK_LEN);
+       os_memset(buf, 0, sizeof(buf));
+
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: MSK", msk, EAP_MSK_LEN);
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: EMSK", msk, EAP_EMSK_LEN);
+
+       return 0;
+}
+
+
+static int eap_eke_mac(u8 mac, const u8 *key, const u8 *data, size_t data_len,
+                      u8 *res)
+{
+       if (mac == EAP_EKE_MAC_HMAC_SHA1)
+               return hmac_sha1(key, SHA1_MAC_LEN, data, data_len, res);
+       if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
+               return hmac_sha256(key, SHA256_MAC_LEN, data, data_len, res);
+       return -1;
+}
+
+
+int eap_eke_prot(struct eap_eke_session *sess,
+                const u8 *data, size_t data_len,
+                u8 *prot, size_t *prot_len)
+{
+       size_t block_size, icv_len, pad;
+       u8 *pos, *iv, *e;
+
+       if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
+               block_size = AES_BLOCK_SIZE;
+       else
+               return -1;
+
+       if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
+               icv_len = SHA1_MAC_LEN;
+       else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
+               icv_len = SHA256_MAC_LEN;
+       else
+               return -1;
+
+       pad = data_len % block_size;
+       if (pad)
+               pad = block_size - pad;
+
+       if (*prot_len < block_size + data_len + pad + icv_len) {
+               wpa_printf(MSG_INFO, "EAP-EKE: Not enough room for Prot() data");
+               return -1;
+       }
+       pos = prot;
+
+       if (random_get_bytes(pos, block_size))
+               return -1;
+       iv = pos;
+       wpa_hexdump(MSG_DEBUG, "EAP-EKE: IV for Prot()", iv, block_size);
+       pos += block_size;
+
+       e = pos;
+       os_memcpy(pos, data, data_len);
+       pos += data_len;
+       if (pad) {
+               if (random_get_bytes(pos, pad))
+                       return -1;
+               pos += pad;
+       }
+
+       if (aes_128_cbc_encrypt(sess->ke, iv, e, data_len + pad) < 0 ||
+           eap_eke_mac(sess->mac, sess->ki, e, data_len + pad, pos) < 0)
+               return -1;
+       pos += icv_len;
+
+       *prot_len = pos - prot;
+       return 0;
+}
+
+
+int eap_eke_decrypt_prot(struct eap_eke_session *sess,
+                        const u8 *prot, size_t prot_len,
+                        u8 *data, size_t *data_len)
+{
+       size_t block_size, icv_len;
+       u8 icv[EAP_EKE_MAX_HASH_LEN];
+
+       if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
+               block_size = AES_BLOCK_SIZE;
+       else
+               return -1;
+
+       if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
+               icv_len = SHA1_MAC_LEN;
+       else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
+               icv_len = SHA256_MAC_LEN;
+       else
+               return -1;
+
+       if (prot_len < 2 * block_size + icv_len ||
+           (prot_len - icv_len) % block_size)
+               return -1;
+
+       if (eap_eke_mac(sess->mac, sess->ki, prot + block_size,
+                       prot_len - block_size - icv_len, icv) < 0)
+               return -1;
+       if (os_memcmp_const(icv, prot + prot_len - icv_len, icv_len) != 0) {
+               wpa_printf(MSG_INFO, "EAP-EKE: ICV mismatch in Prot() data");
+               return -1;
+       }
+
+       if (*data_len < prot_len - block_size - icv_len) {
+               wpa_printf(MSG_INFO, "EAP-EKE: Not enough room for decrypted Prot() data");
+               return -1;
+       }
+
+       *data_len = prot_len - block_size - icv_len;
+       os_memcpy(data, prot + block_size, *data_len);
+       if (aes_128_cbc_decrypt(sess->ke, prot, data, *data_len) < 0) {
+               wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt Prot() data");
+               return -1;
+       }
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Decrypted Prot() data",
+                       data, *data_len);
+
+       return 0;
+}
+
+
+int eap_eke_auth(struct eap_eke_session *sess, const char *label,
+                const struct wpabuf *msgs, u8 *auth)
+{
+       wpa_printf(MSG_DEBUG, "EAP-EKE: Auth(%s)", label);
+       wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ka for Auth",
+                       sess->ka, sess->auth_len);
+       wpa_hexdump_buf(MSG_MSGDUMP, "EAP-EKE: Messages for Auth", msgs);
+       return eap_eke_prf(sess->prf, sess->ka, sess->auth_len,
+                          (const u8 *) label, os_strlen(label),
+                          wpabuf_head(msgs), wpabuf_len(msgs), auth);
+}
+
+
+int eap_eke_session_init(struct eap_eke_session *sess, u8 dhgroup, u8 encr,
+                        u8 prf, u8 mac)
+{
+       sess->dhgroup = dhgroup;
+       sess->encr = encr;
+       sess->prf = prf;
+       sess->mac = mac;
+
+       sess->prf_len = eap_eke_prf_len(prf);
+       sess->nonce_len = eap_eke_nonce_len(prf);
+       sess->auth_len = eap_eke_auth_len(prf);
+       sess->dhcomp_len = eap_eke_dhcomp_len(sess->dhgroup, sess->encr);
+       sess->pnonce_len = eap_eke_pnonce_len(sess->mac);
+       sess->pnonce_ps_len = eap_eke_pnonce_ps_len(sess->mac);
+       if (sess->prf_len < 0 || sess->nonce_len < 0 || sess->auth_len < 0 ||
+           sess->dhcomp_len < 0 || sess->pnonce_len < 0 ||
+           sess->pnonce_ps_len < 0)
+               return -1;
+
+       return 0;
+}
+
+
+void eap_eke_session_clean(struct eap_eke_session *sess)
+{
+       os_memset(sess->shared_secret, 0, EAP_EKE_MAX_HASH_LEN);
+       os_memset(sess->ke, 0, EAP_EKE_MAX_KE_LEN);
+       os_memset(sess->ki, 0, EAP_EKE_MAX_KI_LEN);
+       os_memset(sess->ka, 0, EAP_EKE_MAX_KA_LEN);
+}