/*
* hostapd / EAP-PAX (RFC 4746) server
* Copyright (c) 2005-2007, 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_pax_common.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_STD_1, PAX_STD_3, SUCCESS, FAILURE } state;
u8 mac_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;
u8 ak[EAP_PAX_AK_LEN];
u8 mk[EAP_PAX_MK_LEN];
u8 ck[EAP_PAX_CK_LEN];
u8 ick[EAP_PAX_ICK_LEN];
u8 mid[EAP_PAX_MID_LEN];
int keys_set;
char *cid;
size_t cid_len;
};
static void * eap_pax_init(struct eap_sm *sm)
{
struct eap_pax_data *data;
data = os_zalloc(sizeof(*data));
if (data == NULL)
return NULL;
data->state = PAX_STD_1;
/*
* TODO: make this configurable once EAP_PAX_HMAC_SHA256_128 is
* supported
*/
data->mac_id = EAP_PAX_MAC_HMAC_SHA1_128;
return data;
}
static void eap_pax_reset(struct eap_sm *sm, void *priv)
{
struct eap_pax_data *data = priv;
os_free(data->cid);
bin_clear_free(data, sizeof(*data));
}
static struct wpabuf * eap_pax_build_std_1(struct eap_sm *sm,
struct eap_pax_data *data, u8 id)
{
struct wpabuf *req;
struct eap_pax_hdr *pax;
u8 *pos;
wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (sending)");
if (random_get_bytes(data->rand.r.x, EAP_PAX_RAND_LEN)) {
wpa_printf(MSG_ERROR, "EAP-PAX: Failed to get random data");
data->state = FAILURE;
return NULL;
}
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
sizeof(*pax) + 2 + EAP_PAX_RAND_LEN +
EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id);
if (req == NULL) {
wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
"request");
data->state = FAILURE;
return NULL;
}
pax = wpabuf_put(req, sizeof(*pax));
pax->op_code = EAP_PAX_OP_STD_1;
pax->flags = 0;
pax->mac_id = data->mac_id;
pax->dh_group_id = EAP_PAX_DH_GROUP_NONE;
pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
wpabuf_put_be16(req, EAP_PAX_RAND_LEN);
wpabuf_put_data(req, data->rand.r.x, EAP_PAX_RAND_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: A = X (server rand)",
data->rand.r.x, EAP_PAX_RAND_LEN);
pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
eap_pax_mac(data->mac_id, (u8 *) "", 0,
wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN,
NULL, 0, NULL, 0, pos);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
return req;
}
static struct wpabuf * eap_pax_build_std_3(struct eap_sm *sm,
struct eap_pax_data *data, u8 id)
{
struct wpabuf *req;
struct eap_pax_hdr *pax;
u8 *pos;
wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (sending)");
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
sizeof(*pax) + 2 + EAP_PAX_MAC_LEN +
EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id);
if (req == NULL) {
wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
"request");
data->state = FAILURE;
return NULL;
}
pax = wpabuf_put(req, sizeof(*pax));
pax->op_code = EAP_PAX_OP_STD_3;
pax->flags = 0;
pax->mac_id = data->mac_id;
pax->dh_group_id = EAP_PAX_DH_GROUP_NONE;
pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
wpabuf_put_be16(req, EAP_PAX_MAC_LEN);
pos = wpabuf_put(req, 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, pos);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)",
pos, EAP_PAX_MAC_LEN);
/* Optional ADE could be added here, if needed */
pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN,
NULL, 0, NULL, 0, pos);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
return req;
}
static struct wpabuf * eap_pax_buildReq(struct eap_sm *sm, void *priv, u8 id)
{
struct eap_pax_data *data = priv;
switch (data->state) {
case PAX_STD_1:
return eap_pax_build_std_1(sm, data, id);
case PAX_STD_3:
return eap_pax_build_std_3(sm, data, id);
default:
wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown state %d in buildReq",
data->state);
break;
}
return NULL;
}
static Boolean eap_pax_check(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_pax_data *data = priv;
struct eap_pax_hdr *resp;
const u8 *pos;
size_t len, mlen;
u8 icvbuf[EAP_PAX_ICV_LEN], *icv;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
if (pos == NULL || len < sizeof(*resp)) {
wpa_printf(MSG_INFO, "EAP-PAX: Invalid frame");
return TRUE;
}
mlen = sizeof(struct eap_hdr) + 1 + len;
resp = (struct eap_pax_hdr *) pos;
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",
resp->op_code, resp->flags, resp->mac_id, resp->dh_group_id,
resp->public_key_id);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload",
(u8 *) (resp + 1), len - sizeof(*resp) - EAP_PAX_ICV_LEN);
if (data->state == PAX_STD_1 &&
resp->op_code != EAP_PAX_OP_STD_2) {
wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX_STD-2 - "
"ignore op %d", resp->op_code);
return TRUE;
}
if (data->state == PAX_STD_3 &&
resp->op_code != EAP_PAX_OP_ACK) {
wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX-ACK - "
"ignore op %d", resp->op_code);
return TRUE;
}
if (resp->op_code != EAP_PAX_OP_STD_2 &&
resp->op_code != EAP_PAX_OP_ACK) {
wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown op_code 0x%x",
resp->op_code);
}
if (data->mac_id != resp->mac_id) {
wpa_printf(MSG_DEBUG, "EAP-PAX: Expected MAC ID 0x%x, "
"received 0x%x", data->mac_id, resp->mac_id);
return TRUE;
}
if (resp->dh_group_id != EAP_PAX_DH_GROUP_NONE) {
wpa_printf(MSG_INFO, "EAP-PAX: Expected DH Group ID 0x%x, "
"received 0x%x", EAP_PAX_DH_GROUP_NONE,
resp->dh_group_id);
return TRUE;
}
if (resp->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) {
wpa_printf(MSG_INFO, "EAP-PAX: Expected Public Key ID 0x%x, "
"received 0x%x", EAP_PAX_PUBLIC_KEY_NONE,
resp->public_key_id);
return TRUE;
}
if (resp->flags & EAP_PAX_FLAGS_MF) {
/* TODO: add support for reassembling fragments */
wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported");
return TRUE;
}
if (resp->flags & EAP_PAX_FLAGS_CE) {
wpa_printf(MSG_INFO, "EAP-PAX: Unexpected CE flag");
return TRUE;
}
if (data->keys_set) {
if (len - sizeof(*resp) < EAP_PAX_ICV_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: No ICV in the packet");
return TRUE;
}
icv = wpabuf_mhead_u8(respData) + mlen - EAP_PAX_ICV_LEN;
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN);
eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
wpabuf_mhead(respData),
wpabuf_len(respData) - EAP_PAX_ICV_LEN,
NULL, 0, NULL, 0, icvbuf);
if (os_memcmp_const(icvbuf, icv, EAP_PAX_ICV_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV");
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
icvbuf, EAP_PAX_ICV_LEN);
return TRUE;
}
}
return FALSE;
}
static void eap_pax_process_std_2(struct eap_sm *sm,
struct eap_pax_data *data,
struct wpabuf *respData)
{
struct eap_pax_hdr *resp;
u8 mac[EAP_PAX_MAC_LEN], icvbuf[EAP_PAX_ICV_LEN];
const u8 *pos;
size_t len, left, cid_len;
int i;
if (data->state != PAX_STD_1)
return;
wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX_STD-2");
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
if (pos == NULL || len < sizeof(*resp) + EAP_PAX_ICV_LEN)
return;
resp = (struct eap_pax_hdr *) pos;
pos = (u8 *) (resp + 1);
left = len - sizeof(*resp);
if (left < 2 + EAP_PAX_RAND_LEN ||
WPA_GET_BE16(pos) != EAP_PAX_RAND_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (B)");
return;
}
pos += 2;
left -= 2;
os_memcpy(data->rand.r.y, pos, EAP_PAX_RAND_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)",
data->rand.r.y, EAP_PAX_RAND_LEN);
pos += EAP_PAX_RAND_LEN;
left -= EAP_PAX_RAND_LEN;
if (left < 2 || (size_t) 2 + WPA_GET_BE16(pos) > left) {
wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (CID)");
return;
}
cid_len = WPA_GET_BE16(pos);
if (cid_len > 1500) {
wpa_printf(MSG_INFO, "EAP-PAX: Too long CID");
return;
}
data->cid_len = cid_len;
os_free(data->cid);
data->cid = os_memdup(pos + 2, data->cid_len);
if (data->cid == NULL) {
wpa_printf(MSG_INFO, "EAP-PAX: Failed to allocate memory for "
"CID");
return;
}
pos += 2 + data->cid_len;
left -= 2 + data->cid_len;
wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
(u8 *) data->cid, data->cid_len);
if (left < 2 + EAP_PAX_MAC_LEN ||
WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (MAC_CK)");
return;
}
pos += 2;
left -= 2;
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
pos, EAP_PAX_MAC_LEN);
if (eap_user_get(sm, (u8 *) data->cid, data->cid_len, 0) < 0) {
wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: unknown CID",
(u8 *) data->cid, data->cid_len);
data->state = FAILURE;
return;
}
for (i = 0;
i < EAP_MAX_METHODS &&
(sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
sm->user->methods[i].method != EAP_TYPE_NONE);
i++) {
if (sm->user->methods[i].vendor == EAP_VENDOR_IETF &&
sm->user->methods[i].method == EAP_TYPE_PAX)
break;
}
if (i >= EAP_MAX_METHODS ||
sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
sm->user->methods[i].method != EAP_TYPE_PAX) {
wpa_hexdump_ascii(MSG_DEBUG,
"EAP-PAX: EAP-PAX not enabled for CID",
(u8 *) data->cid, data->cid_len);
data->state = FAILURE;
return;
}
if (sm->user->password == NULL ||
sm->user->password_len != EAP_PAX_AK_LEN) {
wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: invalid password in "
"user database for CID",
(u8 *) data->cid, data->cid_len);
data->state = FAILURE;
return;
}
os_memcpy(data->ak, sm->user->password, EAP_PAX_AK_LEN);
if (eap_pax_initial_key_derivation(data->mac_id, data->ak,
data->rand.e, data->mk, data->ck,
data->ick, data->mid) < 0) {
wpa_printf(MSG_INFO, "EAP-PAX: Failed to complete initial "
"key derivation");
data->state = FAILURE;
return;
}
data->keys_set = 1;
eap_pax_mac(data->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, mac);
if (os_memcmp_const(mac, pos, EAP_PAX_MAC_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(A, B, CID) in "
"PAX_STD-2");
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected MAC_CK(A, B, CID)",
mac, EAP_PAX_MAC_LEN);
data->state = FAILURE;
return;
}
pos += EAP_PAX_MAC_LEN;
left -= EAP_PAX_MAC_LEN;
if (left < EAP_PAX_ICV_LEN) {
wpa_printf(MSG_INFO, "EAP-PAX: Too short ICV (%lu) in "
"PAX_STD-2", (unsigned long) left);
return;
}
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
wpabuf_head(respData),
wpabuf_len(respData) - EAP_PAX_ICV_LEN, NULL, 0, NULL, 0,
icvbuf);
if (os_memcmp_const(icvbuf, pos, EAP_PAX_ICV_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV in PAX_STD-2");
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
icvbuf, EAP_PAX_ICV_LEN);
return;
}
pos += EAP_PAX_ICV_LEN;
left -= EAP_PAX_ICV_LEN;
if (left > 0) {
wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
pos, left);
}
data->state = PAX_STD_3;
}
static void eap_pax_process_ack(struct eap_sm *sm,
struct eap_pax_data *data,
struct wpabuf *respData)
{
if (data->state != PAX_STD_3)
return;
wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX-ACK - authentication "
"completed successfully");
data->state = SUCCESS;
}
static void eap_pax_process(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_pax_data *data = priv;
struct eap_pax_hdr *resp;
const u8 *pos;
size_t len;
if (sm->user == NULL || sm->user->password == NULL) {
wpa_printf(MSG_INFO, "EAP-PAX: Plaintext password not "
"configured");
data->state = FAILURE;
return;
}
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
if (pos == NULL || len < sizeof(*resp))
return;
resp = (struct eap_pax_hdr *) pos;
switch (resp->op_code) {
case EAP_PAX_OP_STD_2:
eap_pax_process_std_2(sm, data, respData);
break;
case EAP_PAX_OP_ACK:
eap_pax_process_ack(sm, data, respData);
break;
}
}
static Boolean eap_pax_isDone(struct eap_sm *sm, void *priv)
{
struct eap_pax_data *data = priv;
return data->state == SUCCESS || data->state == FAILURE;
}
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 != SUCCESS)
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 != SUCCESS)
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;
}
static Boolean eap_pax_isSuccess(struct eap_sm *sm, void *priv)
{
struct eap_pax_data *data = priv;
return data->state == SUCCESS;
}
static u8 * eap_pax_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_pax_data *data = priv;
u8 *sid;
if (data->state != SUCCESS)
return NULL;
sid = os_malloc(1 + EAP_PAX_MID_LEN);
if (sid == NULL)
return NULL;
*len = 1 + EAP_PAX_MID_LEN;
sid[0] = EAP_TYPE_PAX;
os_memcpy(sid + 1, data->mid, EAP_PAX_MID_LEN);
return sid;
}
int eap_server_pax_register(void)
{
struct eap_method *eap;
eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX");
if (eap == NULL)
return -1;
eap->init = eap_pax_init;
eap->reset = eap_pax_reset;
eap->buildReq = eap_pax_buildReq;
eap->check = eap_pax_check;
eap->process = eap_pax_process;
eap->isDone = eap_pax_isDone;
eap->getKey = eap_pax_getKey;
eap->isSuccess = eap_pax_isSuccess;
eap->get_emsk = eap_pax_get_emsk;
eap->getSessionId = eap_pax_get_session_id;
return eap_server_method_register(eap);
}