hostap/src/eap_peer/eap_pax.c

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/*
* EAP peer method: EAP-PAX (RFC 4746)
* Copyright (c) 2005-2008, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/random.h"
#include "eap_common/eap_pax_common.h"
#include "eap_i.h"
/*
* Note: only PAX_STD subprotocol is currently supported
*
* TODO: Add support with PAX_SEC with the mandatory to implement ciphersuite
* (HMAC_SHA1_128, IANA DH Group 14 (2048 bits), RSA-PKCS1-V1_5) and
* recommended ciphersuite (HMAC_SHA256_128, IANA DH Group 15 (3072 bits),
* RSAES-OAEP).
*/
struct eap_pax_data {
enum { PAX_INIT, PAX_STD_2_SENT, PAX_DONE } state;
u8 mac_id, dh_group_id, public_key_id;
union {
u8 e[2 * EAP_PAX_RAND_LEN];
struct {
u8 x[EAP_PAX_RAND_LEN]; /* server rand */
u8 y[EAP_PAX_RAND_LEN]; /* client rand */
} r;
} rand;
char *cid;
size_t cid_len;
u8 ak[EAP_PAX_AK_LEN];
u8 mk[EAP_PAX_MK_LEN];
u8 ck[EAP_PAX_CK_LEN];
u8 ick[EAP_PAX_ICK_LEN];
};
static void eap_pax_deinit(struct eap_sm *sm, void *priv);
static void * eap_pax_init(struct eap_sm *sm)
{
struct eap_pax_data *data;
const u8 *identity, *password;
size_t identity_len, password_len;
identity = eap_get_config_identity(sm, &identity_len);
password = eap_get_config_password(sm, &password_len);
if (!identity || !password) {
wpa_printf(MSG_INFO, "EAP-PAX: CID (nai) or key (password) "
"not configured");
return NULL;
}
if (password_len != EAP_PAX_AK_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: Invalid PSK length");
return NULL;
}
data = os_zalloc(sizeof(*data));
if (data == NULL)
return NULL;
data->state = PAX_INIT;
data->cid = os_malloc(identity_len);
if (data->cid == NULL) {
eap_pax_deinit(sm, data);
return NULL;
}
os_memcpy(data->cid, identity, identity_len);
data->cid_len = identity_len;
os_memcpy(data->ak, password, EAP_PAX_AK_LEN);
return data;
}
static void eap_pax_deinit(struct eap_sm *sm, void *priv)
{
struct eap_pax_data *data = priv;
os_free(data->cid);
os_free(data);
}
static struct wpabuf * eap_pax_alloc_resp(const struct eap_pax_hdr *req,
u8 id, u8 op_code, size_t plen)
{
struct wpabuf *resp;
struct eap_pax_hdr *pax;
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
sizeof(*pax) + plen, EAP_CODE_RESPONSE, id);
if (resp == NULL)
return NULL;
pax = wpabuf_put(resp, sizeof(*pax));
pax->op_code = op_code;
pax->flags = 0;
pax->mac_id = req->mac_id;
pax->dh_group_id = req->dh_group_id;
pax->public_key_id = req->public_key_id;
return resp;
}
static struct wpabuf * eap_pax_process_std_1(struct eap_pax_data *data,
struct eap_method_ret *ret, u8 id,
const struct eap_pax_hdr *req,
size_t req_plen)
{
struct wpabuf *resp;
const u8 *pos;
u8 *rpos;
size_t left, plen;
wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (received)");
if (data->state != PAX_INIT) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 received in "
"unexpected state (%d) - ignored", data->state);
ret->ignore = TRUE;
return NULL;
}
if (req->flags & EAP_PAX_FLAGS_CE) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with CE flag set - "
"ignored");
ret->ignore = TRUE;
return NULL;
}
left = req_plen - sizeof(*req);
if (left < 2 + EAP_PAX_RAND_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with too short "
"payload");
ret->ignore = TRUE;
return NULL;
}
pos = (const u8 *) (req + 1);
if (WPA_GET_BE16(pos) != EAP_PAX_RAND_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with incorrect A "
"length %d (expected %d)",
WPA_GET_BE16(pos), EAP_PAX_RAND_LEN);
ret->ignore = TRUE;
return NULL;
}
pos += 2;
left -= 2;
os_memcpy(data->rand.r.x, pos, EAP_PAX_RAND_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: X (server rand)",
data->rand.r.x, EAP_PAX_RAND_LEN);
pos += EAP_PAX_RAND_LEN;
left -= EAP_PAX_RAND_LEN;
if (left > 0) {
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
pos, left);
}
if (random_get_bytes(data->rand.r.y, EAP_PAX_RAND_LEN)) {
wpa_printf(MSG_ERROR, "EAP-PAX: Failed to get random data");
ret->ignore = TRUE;
return NULL;
}
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)",
data->rand.r.y, EAP_PAX_RAND_LEN);
if (eap_pax_initial_key_derivation(req->mac_id, data->ak, data->rand.e,
data->mk, data->ck, data->ick) < 0)
{
ret->ignore = TRUE;
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-2 (sending)");
plen = 2 + EAP_PAX_RAND_LEN + 2 + data->cid_len + 2 + EAP_PAX_MAC_LEN +
EAP_PAX_ICV_LEN;
resp = eap_pax_alloc_resp(req, id, EAP_PAX_OP_STD_2, plen);
if (resp == NULL)
return NULL;
wpabuf_put_be16(resp, EAP_PAX_RAND_LEN);
wpabuf_put_data(resp, data->rand.r.y, EAP_PAX_RAND_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: B = Y (client rand)",
data->rand.r.y, EAP_PAX_RAND_LEN);
wpabuf_put_be16(resp, data->cid_len);
wpabuf_put_data(resp, data->cid, data->cid_len);
wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
(u8 *) data->cid, data->cid_len);
wpabuf_put_be16(resp, EAP_PAX_MAC_LEN);
rpos = wpabuf_put(resp, EAP_PAX_MAC_LEN);
eap_pax_mac(req->mac_id, data->ck, EAP_PAX_CK_LEN,
data->rand.r.x, EAP_PAX_RAND_LEN,
data->rand.r.y, EAP_PAX_RAND_LEN,
(u8 *) data->cid, data->cid_len, rpos);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
rpos, EAP_PAX_MAC_LEN);
/* Optional ADE could be added here, if needed */
rpos = wpabuf_put(resp, EAP_PAX_ICV_LEN);
eap_pax_mac(req->mac_id, data->ick, EAP_PAX_ICK_LEN,
wpabuf_head(resp), wpabuf_len(resp) - EAP_PAX_ICV_LEN,
NULL, 0, NULL, 0, rpos);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", rpos, EAP_PAX_ICV_LEN);
data->state = PAX_STD_2_SENT;
data->mac_id = req->mac_id;
data->dh_group_id = req->dh_group_id;
data->public_key_id = req->public_key_id;
return resp;
}
static struct wpabuf * eap_pax_process_std_3(struct eap_pax_data *data,
struct eap_method_ret *ret, u8 id,
const struct eap_pax_hdr *req,
size_t req_plen)
{
struct wpabuf *resp;
u8 *rpos, mac[EAP_PAX_MAC_LEN];
const u8 *pos;
size_t left;
wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (received)");
if (data->state != PAX_STD_2_SENT) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 received in "
"unexpected state (%d) - ignored", data->state);
ret->ignore = TRUE;
return NULL;
}
if (req->flags & EAP_PAX_FLAGS_CE) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with CE flag set - "
"ignored");
ret->ignore = TRUE;
return NULL;
}
left = req_plen - sizeof(*req);
if (left < 2 + EAP_PAX_MAC_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with too short "
"payload");
ret->ignore = TRUE;
return NULL;
}
pos = (const u8 *) (req + 1);
if (WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with incorrect "
"MAC_CK length %d (expected %d)",
WPA_GET_BE16(pos), EAP_PAX_MAC_LEN);
ret->ignore = TRUE;
return NULL;
}
pos += 2;
left -= 2;
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)",
pos, EAP_PAX_MAC_LEN);
eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
data->rand.r.y, EAP_PAX_RAND_LEN,
(u8 *) data->cid, data->cid_len, NULL, 0, mac);
if (os_memcmp(pos, mac, EAP_PAX_MAC_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(B, CID) "
"received");
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: expected MAC_CK(B, CID)",
mac, EAP_PAX_MAC_LEN);
ret->methodState = METHOD_DONE;
ret->decision = DECISION_FAIL;
return NULL;
}
pos += EAP_PAX_MAC_LEN;
left -= EAP_PAX_MAC_LEN;
if (left > 0) {
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
pos, left);
}
wpa_printf(MSG_DEBUG, "EAP-PAX: PAX-ACK (sending)");
resp = eap_pax_alloc_resp(req, id, EAP_PAX_OP_ACK, EAP_PAX_ICV_LEN);
if (resp == NULL)
return NULL;
/* Optional ADE could be added here, if needed */
rpos = wpabuf_put(resp, EAP_PAX_ICV_LEN);
eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
wpabuf_head(resp), wpabuf_len(resp) - EAP_PAX_ICV_LEN,
NULL, 0, NULL, 0, rpos);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", rpos, EAP_PAX_ICV_LEN);
data->state = PAX_DONE;
ret->methodState = METHOD_DONE;
ret->decision = DECISION_UNCOND_SUCC;
ret->allowNotifications = FALSE;
return resp;
}
static struct wpabuf * eap_pax_process(struct eap_sm *sm, void *priv,
struct eap_method_ret *ret,
const struct wpabuf *reqData)
{
struct eap_pax_data *data = priv;
const struct eap_pax_hdr *req;
struct wpabuf *resp;
u8 icvbuf[EAP_PAX_ICV_LEN], id;
const u8 *icv, *pos;
size_t len;
u16 flen, mlen;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, reqData, &len);
if (pos == NULL || len < EAP_PAX_ICV_LEN) {
ret->ignore = TRUE;
return NULL;
}
id = eap_get_id(reqData);
req = (const struct eap_pax_hdr *) pos;
flen = len - EAP_PAX_ICV_LEN;
mlen = wpabuf_len(reqData) - EAP_PAX_ICV_LEN;
wpa_printf(MSG_DEBUG, "EAP-PAX: received frame: op_code 0x%x "
"flags 0x%x mac_id 0x%x dh_group_id 0x%x "
"public_key_id 0x%x",
req->op_code, req->flags, req->mac_id, req->dh_group_id,
req->public_key_id);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload",
pos, len - EAP_PAX_ICV_LEN);
if (data->state != PAX_INIT && data->mac_id != req->mac_id) {
wpa_printf(MSG_INFO, "EAP-PAX: MAC ID changed during "
"authentication (was 0x%d, is 0x%d)",
data->mac_id, req->mac_id);
ret->ignore = TRUE;
return NULL;
}
if (data->state != PAX_INIT && data->dh_group_id != req->dh_group_id) {
wpa_printf(MSG_INFO, "EAP-PAX: DH Group ID changed during "
"authentication (was 0x%d, is 0x%d)",
data->dh_group_id, req->dh_group_id);
ret->ignore = TRUE;
return NULL;
}
if (data->state != PAX_INIT &&
data->public_key_id != req->public_key_id) {
wpa_printf(MSG_INFO, "EAP-PAX: Public Key ID changed during "
"authentication (was 0x%d, is 0x%d)",
data->public_key_id, req->public_key_id);
ret->ignore = TRUE;
return NULL;
}
/* TODO: add support EAP_PAX_HMAC_SHA256_128 */
if (req->mac_id != EAP_PAX_MAC_HMAC_SHA1_128) {
wpa_printf(MSG_INFO, "EAP-PAX: Unsupported MAC ID 0x%x",
req->mac_id);
ret->ignore = TRUE;
return NULL;
}
if (req->dh_group_id != EAP_PAX_DH_GROUP_NONE) {
wpa_printf(MSG_INFO, "EAP-PAX: Unsupported DH Group ID 0x%x",
req->dh_group_id);
ret->ignore = TRUE;
return NULL;
}
if (req->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) {
wpa_printf(MSG_INFO, "EAP-PAX: Unsupported Public Key ID 0x%x",
req->public_key_id);
ret->ignore = TRUE;
return NULL;
}
if (req->flags & EAP_PAX_FLAGS_MF) {
/* TODO: add support for reassembling fragments */
wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported - "
"ignored packet");
ret->ignore = TRUE;
return NULL;
}
icv = pos + len - EAP_PAX_ICV_LEN;
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN);
if (req->op_code == EAP_PAX_OP_STD_1) {
eap_pax_mac(req->mac_id, (u8 *) "", 0,
wpabuf_head(reqData), mlen, NULL, 0, NULL, 0,
icvbuf);
} else {
eap_pax_mac(req->mac_id, data->ick, EAP_PAX_ICK_LEN,
wpabuf_head(reqData), mlen, NULL, 0, NULL, 0,
icvbuf);
}
if (os_memcmp(icv, icvbuf, EAP_PAX_ICV_LEN) != 0) {
wpa_printf(MSG_DEBUG, "EAP-PAX: invalid ICV - ignoring the "
"message");
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: expected ICV",
icvbuf, EAP_PAX_ICV_LEN);
ret->ignore = TRUE;
return NULL;
}
ret->ignore = FALSE;
ret->methodState = METHOD_MAY_CONT;
ret->decision = DECISION_FAIL;
ret->allowNotifications = TRUE;
switch (req->op_code) {
case EAP_PAX_OP_STD_1:
resp = eap_pax_process_std_1(data, ret, id, req, flen);
break;
case EAP_PAX_OP_STD_3:
resp = eap_pax_process_std_3(data, ret, id, req, flen);
break;
default:
wpa_printf(MSG_DEBUG, "EAP-PAX: ignoring message with unknown "
"op_code %d", req->op_code);
ret->ignore = TRUE;
return NULL;
}
if (ret->methodState == METHOD_DONE) {
ret->allowNotifications = FALSE;
}
return resp;
}
static Boolean eap_pax_isKeyAvailable(struct eap_sm *sm, void *priv)
{
struct eap_pax_data *data = priv;
return data->state == PAX_DONE;
}
static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_pax_data *data = priv;
u8 *key;
if (data->state != PAX_DONE)
return NULL;
key = os_malloc(EAP_MSK_LEN);
if (key == NULL)
return NULL;
*len = EAP_MSK_LEN;
eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
"Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN,
EAP_MSK_LEN, key);
return key;
}
static u8 * eap_pax_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_pax_data *data = priv;
u8 *key;
if (data->state != PAX_DONE)
return NULL;
key = os_malloc(EAP_EMSK_LEN);
if (key == NULL)
return NULL;
*len = EAP_EMSK_LEN;
eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
"Extended Master Session Key",
data->rand.e, 2 * EAP_PAX_RAND_LEN,
EAP_EMSK_LEN, key);
return key;
}
int eap_peer_pax_register(void)
{
struct eap_method *eap;
int ret;
eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX");
if (eap == NULL)
return -1;
eap->init = eap_pax_init;
eap->deinit = eap_pax_deinit;
eap->process = eap_pax_process;
eap->isKeyAvailable = eap_pax_isKeyAvailable;
eap->getKey = eap_pax_getKey;
eap->get_emsk = eap_pax_get_emsk;
ret = eap_peer_method_register(eap);
if (ret)
eap_peer_method_free(eap);
return ret;
}