/*
* EAP-IKEv2 server (RFC 5106)
* Copyright (c) 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 "eap_i.h"
#include "eap_common/eap_ikev2_common.h"
#include "ikev2.h"
struct eap_ikev2_data {
struct ikev2_initiator_data ikev2;
enum { MSG, FRAG_ACK, WAIT_FRAG_ACK, DONE, FAIL } state;
struct wpabuf *in_buf;
struct wpabuf *out_buf;
size_t out_used;
size_t fragment_size;
int keys_ready;
u8 keymat[EAP_MSK_LEN + EAP_EMSK_LEN];
int keymat_ok;
};
static const u8 * eap_ikev2_get_shared_secret(void *ctx, const u8 *IDr,
size_t IDr_len,
size_t *secret_len)
{
struct eap_sm *sm = ctx;
if (IDr == NULL) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: No IDr received - default "
"to user identity from EAP-Identity");
IDr = sm->identity;
IDr_len = sm->identity_len;
}
if (eap_user_get(sm, IDr, IDr_len, 0) < 0 || sm->user == NULL ||
sm->user->password == NULL) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: No user entry found");
return NULL;
}
*secret_len = sm->user->password_len;
return sm->user->password;
}
static const char * eap_ikev2_state_txt(int state)
{
switch (state) {
case MSG:
return "MSG";
case FRAG_ACK:
return "FRAG_ACK";
case WAIT_FRAG_ACK:
return "WAIT_FRAG_ACK";
case DONE:
return "DONE";
case FAIL:
return "FAIL";
default:
return "?";
}
}
static void eap_ikev2_state(struct eap_ikev2_data *data, int state)
{
wpa_printf(MSG_DEBUG, "EAP-IKEV2: %s -> %s",
eap_ikev2_state_txt(data->state),
eap_ikev2_state_txt(state));
data->state = state;
}
static void * eap_ikev2_init(struct eap_sm *sm)
{
struct eap_ikev2_data *data;
data = os_zalloc(sizeof(*data));
if (data == NULL)
return NULL;
data->state = MSG;
data->fragment_size = sm->fragment_size > 0 ? sm->fragment_size :
IKEV2_FRAGMENT_SIZE;
data->ikev2.state = SA_INIT;
data->ikev2.peer_auth = PEER_AUTH_SECRET;
data->ikev2.key_pad = (u8 *) os_strdup("Key Pad for EAP-IKEv2");
if (data->ikev2.key_pad == NULL)
goto failed;
data->ikev2.key_pad_len = 21;
/* TODO: make proposals configurable */
data->ikev2.proposal.proposal_num = 1;
data->ikev2.proposal.integ = AUTH_HMAC_SHA1_96;
data->ikev2.proposal.prf = PRF_HMAC_SHA1;
data->ikev2.proposal.encr = ENCR_AES_CBC;
data->ikev2.proposal.dh = DH_GROUP2_1024BIT_MODP;
data->ikev2.IDi = (u8 *) os_strdup("hostapd");
data->ikev2.IDi_len = 7;
data->ikev2.get_shared_secret = eap_ikev2_get_shared_secret;
data->ikev2.cb_ctx = sm;
return data;
failed:
ikev2_initiator_deinit(&data->ikev2);
os_free(data);
return NULL;
}
static void eap_ikev2_reset(struct eap_sm *sm, void *priv)
{
struct eap_ikev2_data *data = priv;
wpabuf_free(data->in_buf);
wpabuf_free(data->out_buf);
ikev2_initiator_deinit(&data->ikev2);
os_free(data);
}
static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data, u8 id)
{
struct wpabuf *req;
u8 flags;
size_t send_len, plen, icv_len = 0;
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Request");
flags = 0;
send_len = wpabuf_len(data->out_buf) - data->out_used;
if (1 + send_len > data->fragment_size) {
send_len = data->fragment_size - 1;
flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
if (data->out_used == 0) {
flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
send_len -= 4;
}
}
plen = 1 + send_len;
if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
plen += 4;
if (data->keys_ready) {
const struct ikev2_integ_alg *integ;
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
"Data");
flags |= IKEV2_FLAGS_ICV_INCLUDED;
integ = ikev2_get_integ(data->ikev2.proposal.integ);
if (integ == NULL) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
"transform / cannot generate ICV");
return NULL;
}
icv_len = integ->hash_len;
plen += icv_len;
}
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
EAP_CODE_REQUEST, id);
if (req == NULL)
return NULL;
wpabuf_put_u8(req, flags); /* Flags */
if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
wpabuf_put_be32(req, wpabuf_len(data->out_buf));
wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
send_len);
data->out_used += send_len;
if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
const u8 *msg = wpabuf_head(req);
size_t len = wpabuf_len(req);
ikev2_integ_hash(data->ikev2.proposal.integ,
data->ikev2.keys.SK_ai,
data->ikev2.keys.SK_integ_len,
msg, len, wpabuf_put(req, icv_len));
}
if (data->out_used == wpabuf_len(data->out_buf)) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
"(message sent completely)",
(unsigned long) send_len);
wpabuf_free(data->out_buf);
data->out_buf = NULL;
data->out_used = 0;
} else {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
"(%lu more to send)", (unsigned long) send_len,
(unsigned long) wpabuf_len(data->out_buf) -
data->out_used);
eap_ikev2_state(data, WAIT_FRAG_ACK);
}
return req;
}
static struct wpabuf * eap_ikev2_buildReq(struct eap_sm *sm, void *priv, u8 id)
{
struct eap_ikev2_data *data = priv;
switch (data->state) {
case MSG:
if (data->out_buf == NULL) {
data->out_buf = ikev2_initiator_build(&data->ikev2);
if (data->out_buf == NULL) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
"generate IKEv2 message");
return NULL;
}
data->out_used = 0;
}
/* pass through */
case WAIT_FRAG_ACK:
return eap_ikev2_build_msg(data, id);
case FRAG_ACK:
return eap_ikev2_build_frag_ack(id, EAP_CODE_REQUEST);
default:
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected state %d in "
"buildReq", data->state);
return NULL;
}
}
static Boolean eap_ikev2_check(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
const u8 *pos;
size_t len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
&len);
if (pos == NULL) {
wpa_printf(MSG_INFO, "EAP-IKEV2: Invalid frame");
return TRUE;
}
return FALSE;
}
static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
const struct wpabuf *respData,
u8 flags, const u8 *pos, const u8 **end)
{
if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
int icv_len = eap_ikev2_validate_icv(
data->ikev2.proposal.integ, &data->ikev2.keys, 0,
respData, pos, *end);
if (icv_len < 0)
return -1;
/* Hide Integrity Checksum Data from further processing */
*end -= icv_len;
} else if (data->keys_ready) {
wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
"included integrity checksum");
return -1;
}
return 0;
}
static int eap_ikev2_process_cont(struct eap_ikev2_data *data,
const u8 *buf, size_t len)
{
/* Process continuation of a pending message */
if (len > wpabuf_tailroom(data->in_buf)) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
eap_ikev2_state(data, FAIL);
return -1;
}
wpabuf_put_data(data->in_buf, buf, len);
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting for %lu "
"bytes more", (unsigned long) len,
(unsigned long) wpabuf_tailroom(data->in_buf));
return 0;
}
static int eap_ikev2_process_fragment(struct eap_ikev2_data *data,
u8 flags, u32 message_length,
const u8 *buf, size_t len)
{
/* Process a fragment that is not the last one of the message */
if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
"a fragmented packet");
return -1;
}
if (data->in_buf == NULL) {
/* First fragment of the message */
data->in_buf = wpabuf_alloc(message_length);
if (data->in_buf == NULL) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
"message");
return -1;
}
wpabuf_put_data(data->in_buf, buf, len);
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
"fragment, waiting for %lu bytes more",
(unsigned long) len,
(unsigned long) wpabuf_tailroom(data->in_buf));
}
return 0;
}
static int eap_ikev2_server_keymat(struct eap_ikev2_data *data)
{
if (eap_ikev2_derive_keymat(
data->ikev2.proposal.prf, &data->ikev2.keys,
data->ikev2.i_nonce, data->ikev2.i_nonce_len,
data->ikev2.r_nonce, data->ikev2.r_nonce_len,
data->keymat) < 0) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to derive "
"key material");
return -1;
}
data->keymat_ok = 1;
return 0;
}
static void eap_ikev2_process(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_ikev2_data *data = priv;
const u8 *start, *pos, *end;
size_t len;
u8 flags;
u32 message_length = 0;
struct wpabuf tmpbuf;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
&len);
if (pos == NULL)
return; /* Should not happen; message already verified */
start = pos;
end = start + len;
if (len == 0) {
/* fragment ack */
flags = 0;
} else
flags = *pos++;
if (eap_ikev2_process_icv(data, respData, flags, pos, &end) < 0) {
eap_ikev2_state(data, FAIL);
return;
}
if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
if (end - pos < 4) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
eap_ikev2_state(data, FAIL);
return;
}
message_length = WPA_GET_BE32(pos);
pos += 4;
if (message_length < (u32) (end - pos)) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
"Length (%d; %ld remaining in this msg)",
message_length, (long) (end - pos));
eap_ikev2_state(data, FAIL);
return;
}
}
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
"Message Length %u", flags, message_length);
if (data->state == WAIT_FRAG_ACK) {
if (len != 0) {
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
"in WAIT_FRAG_ACK state");
eap_ikev2_state(data, FAIL);
return;
}
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
eap_ikev2_state(data, MSG);
return;
}
if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
eap_ikev2_state(data, FAIL);
return;
}
if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
if (eap_ikev2_process_fragment(data, flags, message_length,
pos, end - pos) < 0)
eap_ikev2_state(data, FAIL);
else
eap_ikev2_state(data, FRAG_ACK);
return;
} else if (data->state == FRAG_ACK) {
wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
data->state = MSG;
}
if (data->in_buf == NULL) {
/* Wrap unfragmented messages as wpabuf without extra copy */
wpabuf_set(&tmpbuf, pos, end - pos);
data->in_buf = &tmpbuf;
}
if (ikev2_initiator_process(&data->ikev2, data->in_buf) < 0) {
if (data->in_buf == &tmpbuf)
data->in_buf = NULL;
eap_ikev2_state(data, FAIL);
return;
}
switch (data->ikev2.state) {
case SA_AUTH:
/* SA_INIT was sent out, so message have to be
* integrity protected from now on. */
data->keys_ready = 1;
break;
case IKEV2_DONE:
if (data->state == FAIL)
break;
wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication completed "
"successfully");
if (eap_ikev2_server_keymat(data))
break;
eap_ikev2_state(data, DONE);
break;
default:
break;
}
if (data->in_buf != &tmpbuf)
wpabuf_free(data->in_buf);
data->in_buf = NULL;
}
static Boolean eap_ikev2_isDone(struct eap_sm *sm, void *priv)
{
struct eap_ikev2_data *data = priv;
return data->state == DONE || data->state == FAIL;
}
static Boolean eap_ikev2_isSuccess(struct eap_sm *sm, void *priv)
{
struct eap_ikev2_data *data = priv;
return data->state == DONE && data->ikev2.state == IKEV2_DONE &&
data->keymat_ok;
}
static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_ikev2_data *data = priv;
u8 *key;
if (data->state != DONE || !data->keymat_ok)
return NULL;
key = os_malloc(EAP_MSK_LEN);
if (key) {
os_memcpy(key, data->keymat, EAP_MSK_LEN);
*len = EAP_MSK_LEN;
}
return key;
}
static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_ikev2_data *data = priv;
u8 *key;
if (data->state != DONE || !data->keymat_ok)
return NULL;
key = os_malloc(EAP_EMSK_LEN);
if (key) {
os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
*len = EAP_EMSK_LEN;
}
return key;
}
int eap_server_ikev2_register(void)
{
struct eap_method *eap;
int ret;
eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
"IKEV2");
if (eap == NULL)
return -1;
eap->init = eap_ikev2_init;
eap->reset = eap_ikev2_reset;
eap->buildReq = eap_ikev2_buildReq;
eap->check = eap_ikev2_check;
eap->process = eap_ikev2_process;
eap->isDone = eap_ikev2_isDone;
eap->getKey = eap_ikev2_getKey;
eap->isSuccess = eap_ikev2_isSuccess;
eap->get_emsk = eap_ikev2_get_emsk;
ret = eap_server_method_register(eap);
if (ret)
eap_server_method_free(eap);
return ret;
}