/*
* EAP peer method: EAP-pwd (RFC 5931)
* Copyright (c) 2010, Dan Harkins <dharkins@lounge.org>
*
* 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/sha256.h"
#include "crypto/ms_funcs.h"
#include "eap_peer/eap_i.h"
#include "eap_common/eap_pwd_common.h"
struct eap_pwd_data {
enum {
PWD_ID_Req, PWD_Commit_Req, PWD_Confirm_Req,
SUCCESS_ON_FRAG_COMPLETION, SUCCESS, FAILURE
} state;
u8 *id_peer;
size_t id_peer_len;
u8 *id_server;
size_t id_server_len;
u8 *password;
size_t password_len;
int password_hash;
u16 group_num;
EAP_PWD_group *grp;
struct wpabuf *inbuf;
size_t in_frag_pos;
struct wpabuf *outbuf;
size_t out_frag_pos;
size_t mtu;
BIGNUM *k;
BIGNUM *private_value;
BIGNUM *server_scalar;
BIGNUM *my_scalar;
EC_POINT *my_element;
EC_POINT *server_element;
u8 msk[EAP_MSK_LEN];
u8 emsk[EAP_EMSK_LEN];
u8 session_id[1 + SHA256_MAC_LEN];
BN_CTX *bnctx;
};
#ifndef CONFIG_NO_STDOUT_DEBUG
static const char * eap_pwd_state_txt(int state)
{
switch (state) {
case PWD_ID_Req:
return "PWD-ID-Req";
case PWD_Commit_Req:
return "PWD-Commit-Req";
case PWD_Confirm_Req:
return "PWD-Confirm-Req";
case SUCCESS_ON_FRAG_COMPLETION:
return "SUCCESS_ON_FRAG_COMPLETION";
case SUCCESS:
return "SUCCESS";
case FAILURE:
return "FAILURE";
default:
return "PWD-UNK";
}
}
#endif /* CONFIG_NO_STDOUT_DEBUG */
static void eap_pwd_state(struct eap_pwd_data *data, int state)
{
wpa_printf(MSG_DEBUG, "EAP-PWD: %s -> %s",
eap_pwd_state_txt(data->state), eap_pwd_state_txt(state));
data->state = state;
}
static void * eap_pwd_init(struct eap_sm *sm)
{
struct eap_pwd_data *data;
const u8 *identity, *password;
size_t identity_len, password_len;
int fragment_size;
int pwhash;
password = eap_get_config_password2(sm, &password_len, &pwhash);
if (password == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: No password configured!");
return NULL;
}
identity = eap_get_config_identity(sm, &identity_len);
if (identity == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: No identity configured!");
return NULL;
}
if ((data = os_zalloc(sizeof(*data))) == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: memory allocation data fail");
return NULL;
}
if ((data->bnctx = BN_CTX_new()) == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: bn context allocation fail");
os_free(data);
return NULL;
}
if ((data->id_peer = os_malloc(identity_len)) == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
BN_CTX_free(data->bnctx);
os_free(data);
return NULL;
}
os_memcpy(data->id_peer, identity, identity_len);
data->id_peer_len = identity_len;
if ((data->password = os_malloc(password_len)) == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: memory allocation psk fail");
BN_CTX_free(data->bnctx);
bin_clear_free(data->id_peer, data->id_peer_len);
os_free(data);
return NULL;
}
os_memcpy(data->password, password, password_len);
data->password_len = password_len;
data->password_hash = pwhash;
data->out_frag_pos = data->in_frag_pos = 0;
data->inbuf = data->outbuf = NULL;
fragment_size = eap_get_config_fragment_size(sm);
if (fragment_size <= 0)
data->mtu = 1020; /* default from RFC 5931 */
else
data->mtu = fragment_size;
data->state = PWD_ID_Req;
return data;
}
static void eap_pwd_deinit(struct eap_sm *sm, void *priv)
{
struct eap_pwd_data *data = priv;
BN_clear_free(data->private_value);
BN_clear_free(data->server_scalar);
BN_clear_free(data->my_scalar);
BN_clear_free(data->k);
BN_CTX_free(data->bnctx);
EC_POINT_clear_free(data->my_element);
EC_POINT_clear_free(data->server_element);
bin_clear_free(data->id_peer, data->id_peer_len);
bin_clear_free(data->id_server, data->id_server_len);
bin_clear_free(data->password, data->password_len);
if (data->grp) {
EC_GROUP_free(data->grp->group);
EC_POINT_clear_free(data->grp->pwe);
BN_clear_free(data->grp->order);
BN_clear_free(data->grp->prime);
os_free(data->grp);
}
wpabuf_free(data->inbuf);
wpabuf_free(data->outbuf);
bin_clear_free(data, sizeof(*data));
}
static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_pwd_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_pwd_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_pwd_data *data = priv;
u8 *id;
if (data->state != SUCCESS)
return NULL;
id = os_malloc(1 + SHA256_MAC_LEN);
if (id == NULL)
return NULL;
os_memcpy(id, data->session_id, 1 + SHA256_MAC_LEN);
*len = 1 + SHA256_MAC_LEN;
return id;
}
static void
eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
struct eap_method_ret *ret,
const struct wpabuf *reqData,
const u8 *payload, size_t payload_len)
{
struct eap_pwd_id *id;
const u8 *password;
size_t password_len;
u8 pwhashhash[16];
int res;
if (data->state != PWD_ID_Req) {
ret->ignore = TRUE;
eap_pwd_state(data, FAILURE);
return;
}
if (payload_len < sizeof(struct eap_pwd_id)) {
ret->ignore = TRUE;
eap_pwd_state(data, FAILURE);
return;
}
id = (struct eap_pwd_id *) payload;
data->group_num = be_to_host16(id->group_num);
wpa_printf(MSG_DEBUG,
"EAP-PWD: Server EAP-pwd-ID proposal: group=%u random=%u prf=%u prep=%u",
data->group_num, id->random_function, id->prf, id->prep);
if ((id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) ||
(id->prf != EAP_PWD_DEFAULT_PRF)) {
ret->ignore = TRUE;
eap_pwd_state(data, FAILURE);
return;
}
if (id->prep != EAP_PWD_PREP_NONE &&
id->prep != EAP_PWD_PREP_MS) {
wpa_printf(MSG_DEBUG,
"EAP-PWD: Unsupported password pre-processing technique (Prep=%u)",
id->prep);
eap_pwd_state(data, FAILURE);
return;
}
if (id->prep == EAP_PWD_PREP_NONE && data->password_hash) {
wpa_printf(MSG_DEBUG,
"EAP-PWD: Unhashed password not available");
eap_pwd_state(data, FAILURE);
return;
}
wpa_printf(MSG_DEBUG, "EAP-PWD (peer): using group %d",
data->group_num);
data->id_server = os_malloc(payload_len - sizeof(struct eap_pwd_id));
if (data->id_server == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
eap_pwd_state(data, FAILURE);
return;
}
data->id_server_len = payload_len - sizeof(struct eap_pwd_id);
os_memcpy(data->id_server, id->identity, data->id_server_len);
wpa_hexdump_ascii(MSG_INFO, "EAP-PWD (peer): server sent id of",
data->id_server, data->id_server_len);
data->grp = os_zalloc(sizeof(EAP_PWD_group));
if (data->grp == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for "
"group");
eap_pwd_state(data, FAILURE);
return;
}
if (id->prep == EAP_PWD_PREP_MS) {
#ifdef CONFIG_FIPS
wpa_printf(MSG_ERROR,
"EAP-PWD (peer): MS password hash not supported in FIPS mode");
eap_pwd_state(data, FAILURE);
return;
#else /* CONFIG_FIPS */
if (data->password_hash) {
res = hash_nt_password_hash(data->password, pwhashhash);
} else {
u8 pwhash[16];
res = nt_password_hash(data->password,
data->password_len, pwhash);
if (res == 0)
res = hash_nt_password_hash(pwhash, pwhashhash);
os_memset(pwhash, 0, sizeof(pwhash));
}
if (res) {
eap_pwd_state(data, FAILURE);
return;
}
password = pwhashhash;
password_len = sizeof(pwhashhash);
#endif /* CONFIG_FIPS */
} else {
password = data->password;
password_len = data->password_len;
}
/* compute PWE */
res = compute_password_element(data->grp, data->group_num,
password, password_len,
data->id_server, data->id_server_len,
data->id_peer, data->id_peer_len,
id->token);
os_memset(pwhashhash, 0, sizeof(pwhashhash));
if (res) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute PWE");
eap_pwd_state(data, FAILURE);
return;
}
wpa_printf(MSG_DEBUG, "EAP-PWD (peer): computed %d bit PWE...",
BN_num_bits(data->grp->prime));
data->outbuf = wpabuf_alloc(sizeof(struct eap_pwd_id) +
data->id_peer_len);
if (data->outbuf == NULL) {
eap_pwd_state(data, FAILURE);
return;
}
wpabuf_put_be16(data->outbuf, data->group_num);
wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_RAND_FUNC);
wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_PRF);
wpabuf_put_data(data->outbuf, id->token, sizeof(id->token));
wpabuf_put_u8(data->outbuf, EAP_PWD_PREP_NONE);
wpabuf_put_data(data->outbuf, data->id_peer, data->id_peer_len);
eap_pwd_state(data, PWD_Commit_Req);
}
static void
eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
struct eap_method_ret *ret,
const struct wpabuf *reqData,
const u8 *payload, size_t payload_len)
{
EC_POINT *K = NULL, *point = NULL;
BIGNUM *mask = NULL, *x = NULL, *y = NULL, *cofactor = NULL;
u16 offset;
u8 *ptr, *scalar = NULL, *element = NULL;
size_t prime_len, order_len;
if (data->state != PWD_Commit_Req) {
ret->ignore = TRUE;
goto fin;
}
prime_len = BN_num_bytes(data->grp->prime);
order_len = BN_num_bytes(data->grp->order);
if (payload_len != 2 * prime_len + order_len) {
wpa_printf(MSG_INFO,
"EAP-pwd: Unexpected Commit payload length %u (expected %u)",
(unsigned int) payload_len,
(unsigned int) (2 * prime_len + order_len));
goto fin;
}
if (((data->private_value = BN_new()) == NULL) ||
((data->my_element = EC_POINT_new(data->grp->group)) == NULL) ||
((cofactor = BN_new()) == NULL) ||
((data->my_scalar = BN_new()) == NULL) ||
((mask = BN_new()) == NULL)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): scalar allocation fail");
goto fin;
}
if (!EC_GROUP_get_cofactor(data->grp->group, cofactor, NULL)) {
wpa_printf(MSG_INFO, "EAP-pwd (peer): unable to get cofactor "
"for curve");
goto fin;
}
if (BN_rand_range(data->private_value, data->grp->order) != 1 ||
BN_rand_range(mask, data->grp->order) != 1 ||
BN_add(data->my_scalar, data->private_value, mask) != 1 ||
BN_mod(data->my_scalar, data->my_scalar, data->grp->order,
data->bnctx) != 1) {
wpa_printf(MSG_INFO,
"EAP-pwd (peer): unable to get randomness");
goto fin;
}
if (!EC_POINT_mul(data->grp->group, data->my_element, NULL,
data->grp->pwe, mask, data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): element allocation "
"fail");
eap_pwd_state(data, FAILURE);
goto fin;
}
if (!EC_POINT_invert(data->grp->group, data->my_element, data->bnctx))
{
wpa_printf(MSG_INFO, "EAP-PWD (peer): element inversion fail");
goto fin;
}
if (((x = BN_new()) == NULL) ||
((y = BN_new()) == NULL)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): point allocation fail");
goto fin;
}
/* process the request */
if (((data->server_scalar = BN_new()) == NULL) ||
((data->k = BN_new()) == NULL) ||
((K = EC_POINT_new(data->grp->group)) == NULL) ||
((point = EC_POINT_new(data->grp->group)) == NULL) ||
((data->server_element = EC_POINT_new(data->grp->group)) == NULL))
{
wpa_printf(MSG_INFO, "EAP-PWD (peer): peer data allocation "
"fail");
goto fin;
}
/* element, x then y, followed by scalar */
ptr = (u8 *) payload;
BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), x);
ptr += BN_num_bytes(data->grp->prime);
BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), y);
ptr += BN_num_bytes(data->grp->prime);
BN_bin2bn(ptr, BN_num_bytes(data->grp->order), data->server_scalar);
if (!EC_POINT_set_affine_coordinates_GFp(data->grp->group,
data->server_element, x, y,
data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): setting peer element "
"fail");
goto fin;
}
/* check to ensure server's element is not in a small sub-group */
if (BN_cmp(cofactor, BN_value_one())) {
if (!EC_POINT_mul(data->grp->group, point, NULL,
data->server_element, cofactor, NULL)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply "
"server element by order!\n");
goto fin;
}
if (EC_POINT_is_at_infinity(data->grp->group, point)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): server element "
"is at infinity!\n");
goto fin;
}
}
/* compute the shared key, k */
if ((!EC_POINT_mul(data->grp->group, K, NULL, data->grp->pwe,
data->server_scalar, data->bnctx)) ||
(!EC_POINT_add(data->grp->group, K, K, data->server_element,
data->bnctx)) ||
(!EC_POINT_mul(data->grp->group, K, NULL, K, data->private_value,
data->bnctx))) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): computing shared key "
"fail");
goto fin;
}
/* ensure that the shared key isn't in a small sub-group */
if (BN_cmp(cofactor, BN_value_one())) {
if (!EC_POINT_mul(data->grp->group, K, NULL, K, cofactor,
NULL)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply "
"shared key point by order");
goto fin;
}
}
/*
* This check is strictly speaking just for the case above where
* co-factor > 1 but it was suggested that even though this is probably
* never going to happen it is a simple and safe check "just to be
* sure" so let's be safe.
*/
if (EC_POINT_is_at_infinity(data->grp->group, K)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): shared key point is at "
"infinity!\n");
goto fin;
}
if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, K, data->k,
NULL, data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to extract "
"shared secret from point");
goto fin;
}
/* now do the response */
if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
data->my_element, x, y,
data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): point assignment fail");
goto fin;
}
if (((scalar = os_malloc(BN_num_bytes(data->grp->order))) == NULL) ||
((element = os_malloc(BN_num_bytes(data->grp->prime) * 2)) ==
NULL)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): data allocation fail");
goto fin;
}
/*
* bignums occupy as little memory as possible so one that is
* sufficiently smaller than the prime or order might need pre-pending
* with zeros.
*/
os_memset(scalar, 0, BN_num_bytes(data->grp->order));
os_memset(element, 0, BN_num_bytes(data->grp->prime) * 2);
offset = BN_num_bytes(data->grp->order) -
BN_num_bytes(data->my_scalar);
BN_bn2bin(data->my_scalar, scalar + offset);
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
BN_bn2bin(x, element + offset);
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset);
data->outbuf = wpabuf_alloc(BN_num_bytes(data->grp->order) +
2 * BN_num_bytes(data->grp->prime));
if (data->outbuf == NULL)
goto fin;
/* we send the element as (x,y) follwed by the scalar */
wpabuf_put_data(data->outbuf, element,
2 * BN_num_bytes(data->grp->prime));
wpabuf_put_data(data->outbuf, scalar, BN_num_bytes(data->grp->order));
fin:
os_free(scalar);
os_free(element);
BN_clear_free(x);
BN_clear_free(y);
BN_clear_free(mask);
BN_clear_free(cofactor);
EC_POINT_clear_free(K);
EC_POINT_clear_free(point);
if (data->outbuf == NULL)
eap_pwd_state(data, FAILURE);
else
eap_pwd_state(data, PWD_Confirm_Req);
}
static void
eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
struct eap_method_ret *ret,
const struct wpabuf *reqData,
const u8 *payload, size_t payload_len)
{
BIGNUM *x = NULL, *y = NULL;
struct crypto_hash *hash;
u32 cs;
u16 grp;
u8 conf[SHA256_MAC_LEN], *cruft = NULL, *ptr;
int offset;
if (data->state != PWD_Confirm_Req) {
ret->ignore = TRUE;
goto fin;
}
if (payload_len != SHA256_MAC_LEN) {
wpa_printf(MSG_INFO,
"EAP-pwd: Unexpected Confirm payload length %u (expected %u)",
(unsigned int) payload_len, SHA256_MAC_LEN);
goto fin;
}
/*
* first build up the ciphersuite which is group | random_function |
* prf
*/
grp = htons(data->group_num);
ptr = (u8 *) &cs;
os_memcpy(ptr, &grp, sizeof(u16));
ptr += sizeof(u16);
*ptr = EAP_PWD_DEFAULT_RAND_FUNC;
ptr += sizeof(u8);
*ptr = EAP_PWD_DEFAULT_PRF;
/* each component of the cruft will be at most as big as the prime */
if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
wpa_printf(MSG_INFO, "EAP-PWD (server): confirm allocation "
"fail");
goto fin;
}
/*
* server's commit is H(k | server_element | server_scalar |
* peer_element | peer_scalar | ciphersuite)
*/
hash = eap_pwd_h_init();
if (hash == NULL)
goto fin;
/*
* zero the memory each time because this is mod prime math and some
* value may start with a few zeros and the previous one did not.
*/
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
BN_bn2bin(data->k, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
/* server element: x, y */
if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
data->server_element, x, y,
data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
"assignment fail");
goto fin;
}
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
BN_bn2bin(x, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
BN_bn2bin(y, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
/* server scalar */
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->order) -
BN_num_bytes(data->server_scalar);
BN_bn2bin(data->server_scalar, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
/* my element: x, y */
if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
data->my_element, x, y,
data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
"assignment fail");
goto fin;
}
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
BN_bn2bin(x, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
BN_bn2bin(y, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
/* my scalar */
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->order) -
BN_num_bytes(data->my_scalar);
BN_bn2bin(data->my_scalar, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
/* the ciphersuite */
eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32));
/* random function fin */
eap_pwd_h_final(hash, conf);
ptr = (u8 *) payload;
if (os_memcmp_const(conf, ptr, SHA256_MAC_LEN)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm did not verify");
goto fin;
}
wpa_printf(MSG_DEBUG, "EAP-pwd (peer): confirm verified");
/*
* compute confirm:
* H(k | peer_element | peer_scalar | server_element | server_scalar |
* ciphersuite)
*/
hash = eap_pwd_h_init();
if (hash == NULL)
goto fin;
/* k */
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
BN_bn2bin(data->k, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
/* my element */
if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
data->my_element, x, y,
data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point "
"assignment fail");
goto fin;
}
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
BN_bn2bin(x, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
BN_bn2bin(y, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
/* my scalar */
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->order) -
BN_num_bytes(data->my_scalar);
BN_bn2bin(data->my_scalar, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
/* server element: x, y */
if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
data->server_element, x, y,
data->bnctx)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point "
"assignment fail");
goto fin;
}
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
BN_bn2bin(x, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
BN_bn2bin(y, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
/* server scalar */
os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
offset = BN_num_bytes(data->grp->order) -
BN_num_bytes(data->server_scalar);
BN_bn2bin(data->server_scalar, cruft + offset);
eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
/* the ciphersuite */
eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32));
/* all done */
eap_pwd_h_final(hash, conf);
if (compute_keys(data->grp, data->bnctx, data->k,
data->my_scalar, data->server_scalar, conf, ptr,
&cs, data->msk, data->emsk, data->session_id) < 0) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute MSK | "
"EMSK");
goto fin;
}
data->outbuf = wpabuf_alloc(SHA256_MAC_LEN);
if (data->outbuf == NULL)
goto fin;
wpabuf_put_data(data->outbuf, conf, SHA256_MAC_LEN);
fin:
if (data->grp)
bin_clear_free(cruft, BN_num_bytes(data->grp->prime));
BN_clear_free(x);
BN_clear_free(y);
if (data->outbuf == NULL) {
ret->methodState = METHOD_DONE;
ret->decision = DECISION_FAIL;
eap_pwd_state(data, FAILURE);
} else {
eap_pwd_state(data, SUCCESS_ON_FRAG_COMPLETION);
}
}
static struct wpabuf *
eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
const struct wpabuf *reqData)
{
struct eap_pwd_data *data = priv;
struct wpabuf *resp = NULL;
const u8 *pos, *buf;
size_t len;
u16 tot_len = 0;
u8 lm_exch;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, reqData, &len);
if ((pos == NULL) || (len < 1)) {
wpa_printf(MSG_DEBUG, "EAP-pwd: Got a frame but pos is %s and "
"len is %d",
pos == NULL ? "NULL" : "not NULL", (int) len);
ret->ignore = TRUE;
return NULL;
}
ret->ignore = FALSE;
ret->methodState = METHOD_MAY_CONT;
ret->decision = DECISION_FAIL;
ret->allowNotifications = FALSE;
lm_exch = *pos;
pos++; /* skip over the bits and the exch */
len--;
/*
* we're fragmenting so send out the next fragment
*/
if (data->out_frag_pos) {
/*
* this should be an ACK
*/
if (len)
wpa_printf(MSG_INFO, "Bad Response! Fragmenting but "
"not an ACK");
wpa_printf(MSG_DEBUG, "EAP-pwd: Got an ACK for a fragment");
/*
* check if there are going to be more fragments
*/
len = wpabuf_len(data->outbuf) - data->out_frag_pos;
if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
len = data->mtu - EAP_PWD_HDR_SIZE;
EAP_PWD_SET_MORE_BIT(lm_exch);
}
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE + len,
EAP_CODE_RESPONSE, eap_get_id(reqData));
if (resp == NULL) {
wpa_printf(MSG_INFO, "Unable to allocate memory for "
"next fragment!");
return NULL;
}
wpabuf_put_u8(resp, lm_exch);
buf = wpabuf_head_u8(data->outbuf);
wpabuf_put_data(resp, buf + data->out_frag_pos, len);
data->out_frag_pos += len;
/*
* this is the last fragment so get rid of the out buffer
*/
if (data->out_frag_pos >= wpabuf_len(data->outbuf)) {
wpabuf_free(data->outbuf);
data->outbuf = NULL;
data->out_frag_pos = 0;
}
wpa_printf(MSG_DEBUG, "EAP-pwd: Send %s fragment of %d bytes",
data->out_frag_pos == 0 ? "last" : "next",
(int) len);
if (data->state == SUCCESS_ON_FRAG_COMPLETION) {
ret->methodState = METHOD_DONE;
ret->decision = DECISION_UNCOND_SUCC;
eap_pwd_state(data, SUCCESS);
}
return resp;
}
/*
* see if this is a fragment that needs buffering
*
* if it's the first fragment there'll be a length field
*/
if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
if (len < 2) {
wpa_printf(MSG_DEBUG,
"EAP-pwd: Frame too short to contain Total-Length field");
ret->ignore = TRUE;
return NULL;
}
tot_len = WPA_GET_BE16(pos);
wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments whose "
"total length = %d", tot_len);
if (tot_len > 15000)
return NULL;
if (data->inbuf) {
wpa_printf(MSG_DEBUG,
"EAP-pwd: Unexpected new fragment start when previous fragment is still in use");
ret->ignore = TRUE;
return NULL;
}
data->inbuf = wpabuf_alloc(tot_len);
if (data->inbuf == NULL) {
wpa_printf(MSG_INFO, "Out of memory to buffer "
"fragments!");
return NULL;
}
data->in_frag_pos = 0;
pos += sizeof(u16);
len -= sizeof(u16);
}
/*
* buffer and ACK the fragment
*/
if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
data->in_frag_pos += len;
if (data->in_frag_pos > wpabuf_size(data->inbuf)) {
wpa_printf(MSG_INFO, "EAP-pwd: Buffer overflow attack "
"detected (%d vs. %d)!",
(int) data->in_frag_pos,
(int) wpabuf_len(data->inbuf));
wpabuf_free(data->inbuf);
data->inbuf = NULL;
data->in_frag_pos = 0;
return NULL;
}
wpabuf_put_data(data->inbuf, pos, len);
}
if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE,
EAP_CODE_RESPONSE, eap_get_id(reqData));
if (resp != NULL)
wpabuf_put_u8(resp, (EAP_PWD_GET_EXCHANGE(lm_exch)));
wpa_printf(MSG_DEBUG, "EAP-pwd: ACKing a %d byte fragment",
(int) len);
return resp;
}
/*
* we're buffering and this is the last fragment
*/
if (data->in_frag_pos) {
wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
(int) len);
pos = wpabuf_head_u8(data->inbuf);
len = data->in_frag_pos;
}
wpa_printf(MSG_DEBUG, "EAP-pwd: processing frame: exch %d, len %d",
EAP_PWD_GET_EXCHANGE(lm_exch), (int) len);
switch (EAP_PWD_GET_EXCHANGE(lm_exch)) {
case EAP_PWD_OPCODE_ID_EXCH:
eap_pwd_perform_id_exchange(sm, data, ret, reqData,
pos, len);
break;
case EAP_PWD_OPCODE_COMMIT_EXCH:
eap_pwd_perform_commit_exchange(sm, data, ret, reqData,
pos, len);
break;
case EAP_PWD_OPCODE_CONFIRM_EXCH:
eap_pwd_perform_confirm_exchange(sm, data, ret, reqData,
pos, len);
break;
default:
wpa_printf(MSG_INFO, "EAP-pwd: Ignoring message with unknown "
"opcode %d", lm_exch);
break;
}
/*
* if we buffered the just processed input now's the time to free it
*/
if (data->in_frag_pos) {
wpabuf_free(data->inbuf);
data->inbuf = NULL;
data->in_frag_pos = 0;
}
if (data->outbuf == NULL) {
ret->methodState = METHOD_DONE;
ret->decision = DECISION_FAIL;
return NULL; /* generic failure */
}
/*
* we have output! Do we need to fragment it?
*/
lm_exch = EAP_PWD_GET_EXCHANGE(lm_exch);
len = wpabuf_len(data->outbuf);
if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, data->mtu,
EAP_CODE_RESPONSE, eap_get_id(reqData));
/*
* if so it's the first so include a length field
*/
EAP_PWD_SET_LENGTH_BIT(lm_exch);
EAP_PWD_SET_MORE_BIT(lm_exch);
tot_len = len;
/*
* keep the packet at the MTU
*/
len = data->mtu - EAP_PWD_HDR_SIZE - sizeof(u16);
wpa_printf(MSG_DEBUG, "EAP-pwd: Fragmenting output, total "
"length = %d", tot_len);
} else {
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE + len,
EAP_CODE_RESPONSE, eap_get_id(reqData));
}
if (resp == NULL)
return NULL;
wpabuf_put_u8(resp, lm_exch);
if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
wpabuf_put_be16(resp, tot_len);
data->out_frag_pos += len;
}
buf = wpabuf_head_u8(data->outbuf);
wpabuf_put_data(resp, buf, len);
/*
* if we're not fragmenting then there's no need to carry this around
*/
if (data->out_frag_pos == 0) {
wpabuf_free(data->outbuf);
data->outbuf = NULL;
data->out_frag_pos = 0;
if (data->state == SUCCESS_ON_FRAG_COMPLETION) {
ret->methodState = METHOD_DONE;
ret->decision = DECISION_UNCOND_SUCC;
eap_pwd_state(data, SUCCESS);
}
}
return resp;
}
static Boolean eap_pwd_key_available(struct eap_sm *sm, void *priv)
{
struct eap_pwd_data *data = priv;
return data->state == SUCCESS;
}
static u8 * eap_pwd_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_pwd_data *data = priv;
u8 *key;
if (data->state != SUCCESS)
return NULL;
if ((key = os_malloc(EAP_EMSK_LEN)) == NULL)
return NULL;
os_memcpy(key, data->emsk, EAP_EMSK_LEN);
*len = EAP_EMSK_LEN;
return key;
}
int eap_peer_pwd_register(void)
{
struct eap_method *eap;
eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_PWD, "PWD");
if (eap == NULL)
return -1;
eap->init = eap_pwd_init;
eap->deinit = eap_pwd_deinit;
eap->process = eap_pwd_process;
eap->isKeyAvailable = eap_pwd_key_available;
eap->getKey = eap_pwd_getkey;
eap->getSessionId = eap_pwd_get_session_id;
eap->get_emsk = eap_pwd_get_emsk;
return eap_peer_method_register(eap);
}