/*
* hostapd / EAP-SAKE (RFC 4763) server
* Copyright (c) 2006-2007, 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_server/eap_i.h"
#include "eap_common/eap_sake_common.h"
struct eap_sake_data {
enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state;
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;
u8 *peerid;
size_t peerid_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_init(struct eap_sm *sm)
{
struct eap_sake_data *data;
data = os_zalloc(sizeof(*data));
if (data == NULL)
return NULL;
data->state = CHALLENGE;
if (os_get_random(&data->session_id, 1)) {
wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
os_free(data);
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: Initialized Session ID %d",
data->session_id);
return data;
}
static void eap_sake_reset(struct eap_sm *sm, void *priv)
{
struct eap_sake_data *data = priv;
os_free(data->peerid);
bin_clear_free(data, sizeof(*data));
}
static struct wpabuf * eap_sake_build_msg(struct eap_sake_data *data,
u8 id, size_t length, u8 subtype)
{
struct eap_sake_hdr *sake;
struct wpabuf *msg;
size_t plen;
plen = sizeof(struct eap_sake_hdr) + length;
msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_SAKE, plen,
EAP_CODE_REQUEST, 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_build_identity(struct eap_sm *sm,
struct eap_sake_data *data,
u8 id)
{
struct wpabuf *msg;
size_t plen;
wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Identity");
plen = 4;
plen += 2 + sm->server_id_len;
msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_IDENTITY);
if (msg == NULL) {
data->state = FAILURE;
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PERM_ID_REQ");
eap_sake_add_attr(msg, EAP_SAKE_AT_PERM_ID_REQ, NULL, 2);
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID,
sm->server_id, sm->server_id_len);
return msg;
}
static struct wpabuf * eap_sake_build_challenge(struct eap_sm *sm,
struct eap_sake_data *data,
u8 id)
{
struct wpabuf *msg;
size_t plen;
wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge");
if (random_get_bytes(data->rand_s, EAP_SAKE_RAND_LEN)) {
wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
data->state = FAILURE;
return NULL;
}
wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
data->rand_s, EAP_SAKE_RAND_LEN);
plen = 2 + EAP_SAKE_RAND_LEN + 2 + sm->server_id_len;
msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_CHALLENGE);
if (msg == NULL) {
data->state = FAILURE;
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_S");
eap_sake_add_attr(msg, EAP_SAKE_AT_RAND_S,
data->rand_s, EAP_SAKE_RAND_LEN);
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID,
sm->server_id, sm->server_id_len);
return msg;
}
static struct wpabuf * eap_sake_build_confirm(struct eap_sm *sm,
struct eap_sake_data *data,
u8 id)
{
struct wpabuf *msg;
u8 *mic;
wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Confirm");
msg = eap_sake_build_msg(data, id, 2 + EAP_SAKE_MIC_LEN,
EAP_SAKE_SUBTYPE_CONFIRM);
if (msg == NULL) {
data->state = FAILURE;
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_S");
wpabuf_put_u8(msg, EAP_SAKE_AT_MIC_S);
wpabuf_put_u8(msg, 2 + EAP_SAKE_MIC_LEN);
mic = wpabuf_put(msg, EAP_SAKE_MIC_LEN);
if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
sm->server_id, sm->server_id_len,
data->peerid, data->peerid_len, 0,
wpabuf_head(msg), wpabuf_len(msg), mic, mic))
{
wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
data->state = FAILURE;
os_free(msg);
return NULL;
}
return msg;
}
static struct wpabuf * eap_sake_buildReq(struct eap_sm *sm, void *priv, u8 id)
{
struct eap_sake_data *data = priv;
switch (data->state) {
case IDENTITY:
return eap_sake_build_identity(sm, data, id);
case CHALLENGE:
return eap_sake_build_challenge(sm, data, id);
case CONFIRM:
return eap_sake_build_confirm(sm, data, id);
default:
wpa_printf(MSG_DEBUG, "EAP-SAKE: Unknown state %d in buildReq",
data->state);
break;
}
return NULL;
}
static Boolean eap_sake_check(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_sake_data *data = priv;
struct eap_sake_hdr *resp;
size_t len;
u8 version, session_id, subtype;
const u8 *pos;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len);
if (pos == NULL || len < sizeof(struct eap_sake_hdr)) {
wpa_printf(MSG_INFO, "EAP-SAKE: Invalid frame");
return TRUE;
}
resp = (struct eap_sake_hdr *) pos;
version = resp->version;
session_id = resp->session_id;
subtype = resp->subtype;
if (version != EAP_SAKE_VERSION) {
wpa_printf(MSG_INFO, "EAP-SAKE: Unknown version %d", version);
return TRUE;
}
if (session_id != data->session_id) {
wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
session_id, data->session_id);
return TRUE;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype=%d", subtype);
if (data->state == IDENTITY && subtype == EAP_SAKE_SUBTYPE_IDENTITY)
return FALSE;
if (data->state == CHALLENGE && subtype == EAP_SAKE_SUBTYPE_CHALLENGE)
return FALSE;
if (data->state == CONFIRM && subtype == EAP_SAKE_SUBTYPE_CONFIRM)
return FALSE;
if (subtype == EAP_SAKE_SUBTYPE_AUTH_REJECT)
return FALSE;
wpa_printf(MSG_INFO, "EAP-SAKE: Unexpected subtype=%d in state=%d",
subtype, data->state);
return TRUE;
}
static void eap_sake_process_identity(struct eap_sm *sm,
struct eap_sake_data *data,
const struct wpabuf *respData,
const u8 *payload, size_t payloadlen)
{
if (data->state != IDENTITY)
return;
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Identity");
/* TODO: update identity and select new user data */
eap_sake_state(data, CHALLENGE);
}
static void eap_sake_process_challenge(struct eap_sm *sm,
struct eap_sake_data *data,
const struct wpabuf *respData,
const u8 *payload, size_t payloadlen)
{
struct eap_sake_parse_attr attr;
u8 mic_p[EAP_SAKE_MIC_LEN];
if (data->state != CHALLENGE)
return;
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Challenge");
if (eap_sake_parse_attributes(payload, payloadlen, &attr))
return;
if (!attr.rand_p || !attr.mic_p) {
wpa_printf(MSG_INFO, "EAP-SAKE: Response/Challenge did not "
"include AT_RAND_P or AT_MIC_P");
return;
}
os_memcpy(data->rand_p, attr.rand_p, EAP_SAKE_RAND_LEN);
os_free(data->peerid);
data->peerid = NULL;
data->peerid_len = 0;
if (attr.peerid) {
data->peerid = os_malloc(attr.peerid_len);
if (data->peerid == NULL)
return;
os_memcpy(data->peerid, attr.peerid, attr.peerid_len);
data->peerid_len = attr.peerid_len;
}
if (sm->user == NULL || sm->user->password == NULL ||
sm->user->password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) {
wpa_printf(MSG_INFO, "EAP-SAKE: Plaintext password with "
"%d-byte key not configured",
2 * EAP_SAKE_ROOT_SECRET_LEN);
data->state = FAILURE;
return;
}
eap_sake_derive_keys(sm->user->password,
sm->user->password + EAP_SAKE_ROOT_SECRET_LEN,
data->rand_s, data->rand_p,
(u8 *) &data->tek, data->msk, data->emsk);
eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
sm->server_id, sm->server_id_len,
data->peerid, data->peerid_len, 1,
wpabuf_head(respData), wpabuf_len(respData),
attr.mic_p, mic_p);
if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
eap_sake_state(data, FAILURE);
return;
}
eap_sake_state(data, CONFIRM);
}
static void eap_sake_process_confirm(struct eap_sm *sm,
struct eap_sake_data *data,
const struct wpabuf *respData,
const u8 *payload, size_t payloadlen)
{
struct eap_sake_parse_attr attr;
u8 mic_p[EAP_SAKE_MIC_LEN];
if (data->state != CONFIRM)
return;
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Confirm");
if (eap_sake_parse_attributes(payload, payloadlen, &attr))
return;
if (!attr.mic_p) {
wpa_printf(MSG_INFO, "EAP-SAKE: Response/Confirm did not "
"include AT_MIC_P");
return;
}
eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
sm->server_id, sm->server_id_len,
data->peerid, data->peerid_len, 1,
wpabuf_head(respData), wpabuf_len(respData),
attr.mic_p, mic_p);
if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
eap_sake_state(data, FAILURE);
} else
eap_sake_state(data, SUCCESS);
}
static void eap_sake_process_auth_reject(struct eap_sm *sm,
struct eap_sake_data *data,
const struct wpabuf *respData,
const u8 *payload, size_t payloadlen)
{
wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Auth-Reject");
eap_sake_state(data, FAILURE);
}
static void eap_sake_process(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_sake_data *data = priv;
struct eap_sake_hdr *resp;
u8 subtype;
size_t len;
const u8 *pos, *end;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len);
if (pos == NULL || len < sizeof(struct eap_sake_hdr))
return;
resp = (struct eap_sake_hdr *) pos;
end = pos + len;
subtype = resp->subtype;
pos = (u8 *) (resp + 1);
wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
pos, end - pos);
switch (subtype) {
case EAP_SAKE_SUBTYPE_IDENTITY:
eap_sake_process_identity(sm, data, respData, pos, end - pos);
break;
case EAP_SAKE_SUBTYPE_CHALLENGE:
eap_sake_process_challenge(sm, data, respData, pos, end - pos);
break;
case EAP_SAKE_SUBTYPE_CONFIRM:
eap_sake_process_confirm(sm, data, respData, pos, end - pos);
break;
case EAP_SAKE_SUBTYPE_AUTH_REJECT:
eap_sake_process_auth_reject(sm, data, respData, pos,
end - pos);
break;
}
}
static Boolean eap_sake_isDone(struct eap_sm *sm, void *priv)
{
struct eap_sake_data *data = priv;
return data->state == SUCCESS || data->state == FAILURE;
}
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_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;
}
static Boolean eap_sake_isSuccess(struct eap_sm *sm, void *priv)
{
struct eap_sake_data *data = priv;
return data->state == SUCCESS;
}
int eap_server_sake_register(void)
{
struct eap_method *eap;
int ret;
eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
if (eap == NULL)
return -1;
eap->init = eap_sake_init;
eap->reset = eap_sake_reset;
eap->buildReq = eap_sake_buildReq;
eap->check = eap_sake_check;
eap->process = eap_sake_process;
eap->isDone = eap_sake_isDone;
eap->getKey = eap_sake_getKey;
eap->isSuccess = eap_sake_isSuccess;
eap->get_emsk = eap_sake_get_emsk;
ret = eap_server_method_register(eap);
if (ret)
eap_server_method_free(eap);
return ret;
}