/*
* EAP peer method: EAP-SAKE (RFC 4763)
* Copyright (c) 2006-2008, 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/random.h"
#include "eap_peer/eap_i.h"
#include "eap_common/eap_sake_common.h"
struct eap_sake_data {
enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state;
u8 root_secret_a[EAP_SAKE_ROOT_SECRET_LEN];
u8 root_secret_b[EAP_SAKE_ROOT_SECRET_LEN];
u8 rand_s[EAP_SAKE_RAND_LEN];
u8 rand_p[EAP_SAKE_RAND_LEN];
struct {
u8 auth[EAP_SAKE_TEK_AUTH_LEN];
u8 cipher[EAP_SAKE_TEK_CIPHER_LEN];
} tek;
u8 msk[EAP_MSK_LEN];
u8 emsk[EAP_EMSK_LEN];
u8 session_id;
int session_id_set;
u8 *peerid;
size_t peerid_len;
u8 *serverid;
size_t serverid_len;
};
static const char * eap_sake_state_txt(int state)
{
switch (state) {
case IDENTITY:
return "IDENTITY";
case CHALLENGE:
return "CHALLENGE";
case CONFIRM:
return "CONFIRM";
case SUCCESS:
return "SUCCESS";
case FAILURE:
return "FAILURE";
default:
return "?";
}
}
static void eap_sake_state(struct eap_sake_data *data, int state)
{
wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s",
eap_sake_state_txt(data->state),
eap_sake_state_txt(state));
data->state = state;
}
static void eap_sake_deinit(struct eap_sm *sm, void *priv);
static void * eap_sake_init(struct eap_sm *sm)
{
struct eap_sake_data *data;
const u8 *identity, *password;
size_t identity_len, password_len;
password = eap_get_config_password(sm, &password_len);
if (!password || password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) {
wpa_printf(MSG_INFO, "EAP-SAKE: No key of correct length "
"configured");
return NULL;
}
data = os_zalloc(sizeof(*data));
if (data == NULL)
return NULL;
data->state = IDENTITY;
identity = eap_get_config_identity(sm, &identity_len);
if (identity) {
data->peerid = os_malloc(identity_len);
if (data->peerid == NULL) {
eap_sake_deinit(sm, data);
return NULL;
}
os_memcpy(data->peerid, identity, identity_len);
data->peerid_len = identity_len;
}
os_memcpy(data->root_secret_a, password, EAP_SAKE_ROOT_SECRET_LEN);
os_memcpy(data->root_secret_b,
password + EAP_SAKE_ROOT_SECRET_LEN,
EAP_SAKE_ROOT_SECRET_LEN);
return data;
}
static void eap_sake_deinit(struct eap_sm *sm, void *priv)
{
struct eap_sake_data *data = priv;
os_free(data->serverid);
os_free(data->peerid);
bin_clear_free(data, sizeof(*data));
}
static struct wpabuf * eap_sake_build_msg(struct eap_sake_data *data,
int id, size_t length, u8 subtype)
{
struct eap_sake_hdr *sake;
struct wpabuf *msg;
size_t plen;
plen = length + sizeof(struct eap_sake_hdr);
msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_SAKE, plen,
EAP_CODE_RESPONSE, id);
if (msg == NULL) {
wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory "
"request");
return NULL;
}
sake = wpabuf_put(msg, sizeof(*sake));
sake->version = EAP_SAKE_VERSION;
sake->session_id = data->session_id;
sake->subtype = subtype;
return msg;
}
static struct wpabuf * eap_sake_process_identity(struct eap_sm *sm,
struct eap_sake_data *data,
struct eap_method_ret *ret,
u8 id,
const u8 *payload,
size_t payload_len)
{
struct eap_sake_parse_attr attr;
struct wpabuf *resp;
if (data->state != IDENTITY) {
ret->ignore = TRUE;
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Identity");
if (eap_sake_parse_attributes(payload, payload_len, &attr))
return NULL;
if (!attr.perm_id_req && !attr.any_id_req) {
wpa_printf(MSG_INFO, "EAP-SAKE: No AT_PERM_ID_REQ or "
"AT_ANY_ID_REQ in Request/Identity");
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Identity");
resp = eap_sake_build_msg(data, id, 2 + data->peerid_len,
EAP_SAKE_SUBTYPE_IDENTITY);
if (resp == NULL)
return NULL;
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID,
data->peerid, data->peerid_len);
eap_sake_state(data, CHALLENGE);
return resp;
}
static struct wpabuf * eap_sake_process_challenge(struct eap_sm *sm,
struct eap_sake_data *data,
struct eap_method_ret *ret,
u8 id,
const u8 *payload,
size_t payload_len)
{
struct eap_sake_parse_attr attr;
struct wpabuf *resp;
u8 *rpos;
size_t rlen;
if (data->state != IDENTITY && data->state != CHALLENGE) {
wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge received "
"in unexpected state (%d)", data->state);
ret->ignore = TRUE;
return NULL;
}
if (data->state == IDENTITY)
eap_sake_state(data, CHALLENGE);
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Challenge");
if (eap_sake_parse_attributes(payload, payload_len, &attr))
return NULL;
if (!attr.rand_s) {
wpa_printf(MSG_INFO, "EAP-SAKE: Request/Challenge did not "
"include AT_RAND_S");
return NULL;
}
os_memcpy(data->rand_s, attr.rand_s, EAP_SAKE_RAND_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
data->rand_s, EAP_SAKE_RAND_LEN);
if (random_get_bytes(data->rand_p, EAP_SAKE_RAND_LEN)) {
wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
return NULL;
}
wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_P (peer rand)",
data->rand_p, EAP_SAKE_RAND_LEN);
os_free(data->serverid);
data->serverid = NULL;
data->serverid_len = 0;
if (attr.serverid) {
wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-SAKE: SERVERID",
attr.serverid, attr.serverid_len);
data->serverid = os_malloc(attr.serverid_len);
if (data->serverid == NULL)
return NULL;
os_memcpy(data->serverid, attr.serverid, attr.serverid_len);
data->serverid_len = attr.serverid_len;
}
eap_sake_derive_keys(data->root_secret_a, data->root_secret_b,
data->rand_s, data->rand_p,
(u8 *) &data->tek, data->msk, data->emsk);
wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Challenge");
rlen = 2 + EAP_SAKE_RAND_LEN + 2 + EAP_SAKE_MIC_LEN;
if (data->peerid)
rlen += 2 + data->peerid_len;
resp = eap_sake_build_msg(data, id, rlen, EAP_SAKE_SUBTYPE_CHALLENGE);
if (resp == NULL)
return NULL;
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_P");
eap_sake_add_attr(resp, EAP_SAKE_AT_RAND_P,
data->rand_p, EAP_SAKE_RAND_LEN);
if (data->peerid) {
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID,
data->peerid, data->peerid_len);
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P);
wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN);
rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN);
if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
data->serverid, data->serverid_len,
data->peerid, data->peerid_len, 1,
wpabuf_head(resp), wpabuf_len(resp), rpos,
rpos)) {
wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
wpabuf_free(resp);
return NULL;
}
eap_sake_state(data, CONFIRM);
return resp;
}
static struct wpabuf * eap_sake_process_confirm(struct eap_sm *sm,
struct eap_sake_data *data,
struct eap_method_ret *ret,
u8 id,
const struct wpabuf *reqData,
const u8 *payload,
size_t payload_len)
{
struct eap_sake_parse_attr attr;
u8 mic_s[EAP_SAKE_MIC_LEN];
struct wpabuf *resp;
u8 *rpos;
if (data->state != CONFIRM) {
ret->ignore = TRUE;
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Confirm");
if (eap_sake_parse_attributes(payload, payload_len, &attr))
return NULL;
if (!attr.mic_s) {
wpa_printf(MSG_INFO, "EAP-SAKE: Request/Confirm did not "
"include AT_MIC_S");
return NULL;
}
eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
data->serverid, data->serverid_len,
data->peerid, data->peerid_len, 0,
wpabuf_head(reqData), wpabuf_len(reqData),
attr.mic_s, mic_s);
if (os_memcmp_const(attr.mic_s, mic_s, EAP_SAKE_MIC_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_S");
eap_sake_state(data, FAILURE);
ret->methodState = METHOD_DONE;
ret->decision = DECISION_FAIL;
ret->allowNotifications = FALSE;
wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending "
"Response/Auth-Reject");
return eap_sake_build_msg(data, id, 0,
EAP_SAKE_SUBTYPE_AUTH_REJECT);
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Confirm");
resp = eap_sake_build_msg(data, id, 2 + EAP_SAKE_MIC_LEN,
EAP_SAKE_SUBTYPE_CONFIRM);
if (resp == NULL)
return NULL;
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P);
wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN);
rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN);
if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
data->serverid, data->serverid_len,
data->peerid, data->peerid_len, 1,
wpabuf_head(resp), wpabuf_len(resp), rpos,
rpos)) {
wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
wpabuf_free(resp);
return NULL;
}
eap_sake_state(data, SUCCESS);
ret->methodState = METHOD_DONE;
ret->decision = DECISION_UNCOND_SUCC;
ret->allowNotifications = FALSE;
return resp;
}
static struct wpabuf * eap_sake_process(struct eap_sm *sm, void *priv,
struct eap_method_ret *ret,
const struct wpabuf *reqData)
{
struct eap_sake_data *data = priv;
const struct eap_sake_hdr *req;
struct wpabuf *resp;
const u8 *pos, *end;
size_t len;
u8 subtype, session_id, id;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, reqData, &len);
if (pos == NULL || len < sizeof(struct eap_sake_hdr)) {
ret->ignore = TRUE;
return NULL;
}
req = (const struct eap_sake_hdr *) pos;
end = pos + len;
id = eap_get_id(reqData);
subtype = req->subtype;
session_id = req->session_id;
pos = (const u8 *) (req + 1);
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype %d "
"session_id %d", subtype, session_id);
wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
pos, end - pos);
if (data->session_id_set && data->session_id != session_id) {
wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
session_id, data->session_id);
ret->ignore = TRUE;
return NULL;
}
data->session_id = session_id;
data->session_id_set = 1;
ret->ignore = FALSE;
ret->methodState = METHOD_MAY_CONT;
ret->decision = DECISION_FAIL;
ret->allowNotifications = TRUE;
switch (subtype) {
case EAP_SAKE_SUBTYPE_IDENTITY:
resp = eap_sake_process_identity(sm, data, ret, id,
pos, end - pos);
break;
case EAP_SAKE_SUBTYPE_CHALLENGE:
resp = eap_sake_process_challenge(sm, data, ret, id,
pos, end - pos);
break;
case EAP_SAKE_SUBTYPE_CONFIRM:
resp = eap_sake_process_confirm(sm, data, ret, id, reqData,
pos, end - pos);
break;
default:
wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring message with "
"unknown subtype %d", subtype);
ret->ignore = TRUE;
return NULL;
}
if (ret->methodState == METHOD_DONE)
ret->allowNotifications = FALSE;
return resp;
}
static Boolean eap_sake_isKeyAvailable(struct eap_sm *sm, void *priv)
{
struct eap_sake_data *data = priv;
return data->state == SUCCESS;
}
static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_sake_data *data = priv;
u8 *key;
if (data->state != SUCCESS)
return NULL;
key = os_malloc(EAP_MSK_LEN);
if (key == NULL)
return NULL;
os_memcpy(key, data->msk, EAP_MSK_LEN);
*len = EAP_MSK_LEN;
return key;
}
static u8 * eap_sake_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_sake_data *data = priv;
u8 *id;
if (data->state != SUCCESS)
return NULL;
*len = 1 + 2 * EAP_SAKE_RAND_LEN;
id = os_malloc(*len);
if (id == NULL)
return NULL;
id[0] = EAP_TYPE_SAKE;
os_memcpy(id + 1, data->rand_s, EAP_SAKE_RAND_LEN);
os_memcpy(id + 1 + EAP_SAKE_RAND_LEN, data->rand_s, EAP_SAKE_RAND_LEN);
wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Derived Session-Id", id, *len);
return id;
}
static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_sake_data *data = priv;
u8 *key;
if (data->state != SUCCESS)
return NULL;
key = os_malloc(EAP_EMSK_LEN);
if (key == NULL)
return NULL;
os_memcpy(key, data->emsk, EAP_EMSK_LEN);
*len = EAP_EMSK_LEN;
return key;
}
int eap_peer_sake_register(void)
{
struct eap_method *eap;
int ret;
eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
if (eap == NULL)
return -1;
eap->init = eap_sake_init;
eap->deinit = eap_sake_deinit;
eap->process = eap_sake_process;
eap->isKeyAvailable = eap_sake_isKeyAvailable;
eap->getKey = eap_sake_getKey;
eap->getSessionId = eap_sake_get_session_id;
eap->get_emsk = eap_sake_get_emsk;
ret = eap_peer_method_register(eap);
if (ret)
eap_peer_method_free(eap);
return ret;
}