static Boolean eap_pwd_check(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_pwd_data *data = priv;
const u8 *pos;
size_t len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, respData, &len);
if (pos == NULL || len < 1) {
wpa_printf(MSG_INFO, "EAP-pwd: Invalid frame");
return TRUE;
}
wpa_printf(MSG_DEBUG, "EAP-pwd: Received frame: exch = %d, len = %d",
EAP_PWD_GET_EXCHANGE(*pos), (int) len);
if (data->state == PWD_ID_Req &&
((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_ID_EXCH))
return FALSE;
if (data->state == PWD_Commit_Req &&
((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_COMMIT_EXCH))
return FALSE;
if (data->state == PWD_Confirm_Req &&
((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_CONFIRM_EXCH))
return FALSE;
wpa_printf(MSG_INFO, "EAP-pwd: Unexpected opcode=%d in state=%d",
*pos, data->state);
return TRUE;
}
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);
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)) {
tot_len = WPA_GET_BE16(pos);
wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments whose "
"total length = %d", tot_len);
data->inbuf = wpabuf_alloc(tot_len);
if (data->inbuf == NULL) {
wpa_printf(MSG_INFO, "Out of memory to buffer "
"fragments!");
return NULL;
}
pos += sizeof(u16);
len -= sizeof(u16);
}
/*
* buffer and ACK the fragment
*/
if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
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->in_frag_pos = 0;
return NULL;
}
wpabuf_put_data(data->inbuf, pos, len);
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) {
wpabuf_put_data(data->inbuf, pos, len);
wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
(int) len);
data->in_frag_pos += 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->in_frag_pos = 0;
}
if (data->outbuf == NULL)
return NULL; /* generic failure */
/*
* we have output! Do we need to fragment it?
*/
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;
}
return resp;
}
static void eap_pwd_process(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_pwd_data *data = priv;
const u8 *pos;
size_t len;
u8 lm_exch;
u16 tot_len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, respData, &len);
if ((pos == NULL) || (len < 1)) {
wpa_printf(MSG_INFO, "Bad EAP header! pos %s and len = %d",
(pos == NULL) ? "is NULL" : "is not NULL",
(int) len);
return;
}
lm_exch = *pos;
pos++; /* skip over the bits and the exch */
len--;
/*
* if we're fragmenting then this should be an ACK with no data,
* just return and continue fragmenting in the "build" section above
*/
if (data->out_frag_pos) {
if (len > 1)
wpa_printf(MSG_INFO, "EAP-pwd: Bad response! "
"Fragmenting but not an ACK");
else
wpa_printf(MSG_DEBUG, "EAP-pwd: received ACK from "
"peer");
return;
}
/*
* if we're receiving fragmented packets then we need to buffer...
*
* the first fragment has a total length
*/
if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
tot_len = WPA_GET_BE16(pos);
wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments, total "
"length = %d", tot_len);
if (tot_len > 15000)
return;
data->inbuf = wpabuf_alloc(tot_len);
if (data->inbuf == NULL) {
wpa_printf(MSG_INFO, "EAP-pwd: Out of memory to "
"buffer fragments!");
return;
}
pos += sizeof(u16);
len -= sizeof(u16);
}
/*
* the first and all intermediate fragments have the M bit set
*/
if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
"attack detected! (%d+%d > %d)",
(int) data->in_frag_pos, (int) len,
(int) wpabuf_size(data->inbuf));
eap_pwd_state(data, FAILURE);
return;
}
wpabuf_put_data(data->inbuf, pos, len);
data->in_frag_pos += len;
wpa_printf(MSG_DEBUG, "EAP-pwd: Got a %d byte fragment",
(int) len);
return;
}
/*
* last fragment won't have the M bit set (but we're obviously
* buffering fragments so that's how we know it's the last)
*/
if (data->in_frag_pos) {
wpabuf_put_data(data->inbuf, pos, len);
data->in_frag_pos += len;
pos = wpabuf_head_u8(data->inbuf);
len = data->in_frag_pos;
wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
(int) len);
}
switch (EAP_PWD_GET_EXCHANGE(lm_exch)) {
case EAP_PWD_OPCODE_ID_EXCH:
eap_pwd_process_id_resp(sm, data, pos, len);
break;
case EAP_PWD_OPCODE_COMMIT_EXCH:
eap_pwd_process_commit_resp(sm, data, pos, len);
break;
case EAP_PWD_OPCODE_CONFIRM_EXCH:
eap_pwd_process_confirm_resp(sm, data, pos, len);
break;
}
/*
* if we had been buffering fragments, here's a great place
* to clean up
*/
if (data->in_frag_pos) {
wpabuf_free(data->inbuf);
data->inbuf = NULL;
data->in_frag_pos = 0;
}
}
static int
mod_authenticate (void *arg, eap_handler_t *handler)
{
pwd_session_t *pwd_session;
pwd_hdr *hdr;
pwd_id_packet *id;
eap_packet_t *response;
REQUEST *request, *fake;
VALUE_PAIR *pw, *vp;
EAP_DS *eap_ds;
int len, ret = 0;
eap_pwd_t *inst = (eap_pwd_t *)arg;
uint16_t offset;
uint8_t exch, *buf, *ptr, msk[MSK_EMSK_LEN], emsk[MSK_EMSK_LEN];
uint8_t peer_confirm[SHA256_DIGEST_LENGTH];
BIGNUM *x = NULL, *y = NULL;
if ((!handler) ||
((eap_ds = handler->eap_ds) == NULL) ||
(!inst)) {
return 0;
}
pwd_session = (pwd_session_t *)handler->opaque;
request = handler->request;
response = handler->eap_ds->response;
hdr = (pwd_hdr *)response->type.data;
buf = hdr->data;
len = response->type.length - sizeof(pwd_hdr);
/*
* see if we're fragmenting, if so continue until we're done
*/
if (pwd_session->out_buf_pos) {
if (len) {
RDEBUG2("pwd got something more than an ACK for a fragment");
}
return send_pwd_request(pwd_session, eap_ds);
}
/*
* the first fragment will have a total length, make a
* buffer to hold all the fragments
*/
if (EAP_PWD_GET_LENGTH_BIT(hdr)) {
if (pwd_session->in_buf) {
RDEBUG2("pwd already alloced buffer for fragments");
return 0;
}
pwd_session->in_buf_len = ntohs(buf[0] * 256 | buf[1]);
if ((pwd_session->in_buf = talloc_zero_array(pwd_session, uint8_t,
pwd_session->in_buf_len)) == NULL) {
RDEBUG2("pwd cannot allocate %d buffer to hold fragments",
pwd_session->in_buf_len);
return 0;
}
memset(pwd_session->in_buf, 0, pwd_session->in_buf_len);
pwd_session->in_buf_pos = 0;
buf += sizeof(uint16_t);
len -= sizeof(uint16_t);
}
/*
* all fragments, including the 1st will have the M(ore) bit set,
* buffer those fragments!
*/
if (EAP_PWD_GET_MORE_BIT(hdr)) {
rad_assert(pwd_session->in_buf != NULL);
if ((pwd_session->in_buf_pos + len) > pwd_session->in_buf_len) {
RDEBUG2("pwd will not overflow a fragment buffer. Nope, not prudent.");
return 0;
}
memcpy(pwd_session->in_buf + pwd_session->in_buf_pos, buf, len);
pwd_session->in_buf_pos += len;
/*
* send back an ACK for this fragment
*/
exch = EAP_PWD_GET_EXCHANGE(hdr);
eap_ds->request->code = PW_EAP_REQUEST;
eap_ds->request->type.num = PW_EAP_PWD;
eap_ds->request->type.length = sizeof(pwd_hdr);
if ((eap_ds->request->type.data = talloc_array(eap_ds->request,
uint8_t, sizeof(pwd_hdr))) == NULL) {
return 0;
}
hdr = (pwd_hdr *)eap_ds->request->type.data;
EAP_PWD_SET_EXCHANGE(hdr, exch);
return 1;
}
if (pwd_session->in_buf) {
/*
* the last fragment...
*/
if ((pwd_session->in_buf_pos + len) > pwd_session->in_buf_len) {
RDEBUG2("pwd will not overflow a fragment buffer. Nope, not prudent.");
return 0;
}
memcpy(pwd_session->in_buf + pwd_session->in_buf_pos, buf, len);
buf = pwd_session->in_buf;
len = pwd_session->in_buf_len;
}
switch (pwd_session->state) {
case PWD_STATE_ID_REQ:
if (EAP_PWD_GET_EXCHANGE(hdr) != EAP_PWD_EXCH_ID) {
RDEBUG2("pwd exchange is incorrect: not ID");
return 0;
}
id = (pwd_id_packet *)buf;
if ((id->prf != EAP_PWD_DEF_PRF) ||
(id->random_function != EAP_PWD_DEF_RAND_FUN) ||
(id->prep != EAP_PWD_PREP_NONE) ||
(memcmp(id->token, (char *)&pwd_session->token, 4)) ||
(id->group_num != ntohs(pwd_session->group_num))) {
RDEBUG2("pwd id response is invalid");
return 0;
}
/*
* we've agreed on the ciphersuite, record it...
*/
ptr = (uint8_t *)&pwd_session->ciphersuite;
memcpy(ptr, (char *)&id->group_num, sizeof(uint16_t));
ptr += sizeof(uint16_t);
*ptr = EAP_PWD_DEF_RAND_FUN;
ptr += sizeof(uint8_t);
*ptr = EAP_PWD_DEF_PRF;
pwd_session->peer_id_len = len - sizeof(pwd_id_packet);
if (pwd_session->peer_id_len >= sizeof(pwd_session->peer_id)) {
RDEBUG2("pwd id response is malformed");
return 0;
}
memcpy(pwd_session->peer_id, id->identity,
pwd_session->peer_id_len);
pwd_session->peer_id[pwd_session->peer_id_len] = '\0';
/*
* make fake request to get the password for the usable ID
*/
if ((fake = request_alloc_fake(handler->request)) == NULL) {
RDEBUG("pwd unable to create fake request!");
return 0;
}
fake->username = pairmake_packet("User-Name", "", T_OP_EQ);
if (!fake->username) {
RDEBUG("pwd unanable to create value pair for username!");
request_free(&fake);
return 0;
}
memcpy(fake->username->vp_strvalue, pwd_session->peer_id,
pwd_session->peer_id_len);
fake->username->length = pwd_session->peer_id_len;
fake->username->vp_strvalue[fake->username->length] = 0;
if ((vp = pairfind(request->config_items, PW_VIRTUAL_SERVER, 0, TAG_ANY)) != NULL) {
fake->server = vp->vp_strvalue;
} else if (inst->conf->virtual_server) {
fake->server = inst->conf->virtual_server;
} /* else fake->server == request->server */
if ((debug_flag > 0) && fr_log_fp) {
RDEBUG("Sending tunneled request");
debug_pair_list(fake->packet->vps);
fprintf(fr_log_fp, "server %s {\n",
(!fake->server) ? "" : fake->server);
}
/*
* Call authorization recursively, which will
* get the password.
*/
process_authorize(0, fake);
/*
* Note that we don't do *anything* with the reply
* attributes.
*/
if ((debug_flag > 0) && fr_log_fp) {
fprintf(fr_log_fp, "} # server %s\n",
(!fake->server) ? "" : fake->server);
RDEBUG("Got tunneled reply code %d", fake->reply->code);
debug_pair_list(fake->reply->vps);
}
if ((pw = pairfind(fake->config_items, PW_CLEARTEXT_PASSWORD, 0, TAG_ANY)) == NULL) {
DEBUG2("failed to find password for %s to do pwd authentication",
pwd_session->peer_id);
request_free(&fake);
return 0;
}
if (compute_password_element(pwd_session, pwd_session->group_num,
pw->data.strvalue, strlen(pw->data.strvalue),
inst->conf->server_id, strlen(inst->conf->server_id),
pwd_session->peer_id, strlen(pwd_session->peer_id),
&pwd_session->token)) {
DEBUG2("failed to obtain password element :-(");
request_free(&fake);
return 0;
}
request_free(&fake);
/*
* compute our scalar and element
*/
if (compute_scalar_element(pwd_session, inst->bnctx)) {
DEBUG2("failed to compute server's scalar and element");
return 0;
}
if (((x = BN_new()) == NULL) ||
((y = BN_new()) == NULL)) {
DEBUG2("server point allocation failed");
return 0;
}
/*
* element is a point, get both coordinates: x and y
*/
if (!EC_POINT_get_affine_coordinates_GFp(pwd_session->group,
pwd_session->my_element, x, y,
inst->bnctx)) {
DEBUG2("server point assignment failed");
BN_free(x);
BN_free(y);
return 0;
}
/*
* construct request
*/
pwd_session->out_buf_len = BN_num_bytes(pwd_session->order) +
(2 * BN_num_bytes(pwd_session->prime));
if ((pwd_session->out_buf = talloc_array(pwd_session, uint8_t,
pwd_session->out_buf_len)) == NULL) {
return 0;
}
memset(pwd_session->out_buf, 0, pwd_session->out_buf_len);
ptr = pwd_session->out_buf;
offset = BN_num_bytes(pwd_session->prime) - BN_num_bytes(x);
BN_bn2bin(x, ptr + offset);
ptr += BN_num_bytes(pwd_session->prime);
offset = BN_num_bytes(pwd_session->prime) - BN_num_bytes(y);
BN_bn2bin(y, ptr + offset);
ptr += BN_num_bytes(pwd_session->prime);
offset = BN_num_bytes(pwd_session->order) - BN_num_bytes(pwd_session->my_scalar);
BN_bn2bin(pwd_session->my_scalar, ptr + offset);
pwd_session->state = PWD_STATE_COMMIT;
ret = send_pwd_request(pwd_session, eap_ds);
break;
case PWD_STATE_COMMIT:
if (EAP_PWD_GET_EXCHANGE(hdr) != EAP_PWD_EXCH_COMMIT) {
RDEBUG2("pwd exchange is incorrect: not commit!");
return 0;
}
/*
* process the peer's commit and generate the shared key, k
*/
if (process_peer_commit(pwd_session, buf, inst->bnctx)) {
RDEBUG2("failed to process peer's commit");
return 0;
}
/*
* compute our confirm blob
*/
if (compute_server_confirm(pwd_session, pwd_session->my_confirm, inst->bnctx)) {
ERROR("rlm_eap_pwd: failed to compute confirm!");
return 0;
}
/*
* construct a response...which is just our confirm blob
*/
pwd_session->out_buf_len = SHA256_DIGEST_LENGTH;
if ((pwd_session->out_buf = talloc_array(pwd_session, uint8_t,
pwd_session->out_buf_len)) == NULL) {
return 0;
}
memset(pwd_session->out_buf, 0, pwd_session->out_buf_len);
memcpy(pwd_session->out_buf, pwd_session->my_confirm, SHA256_DIGEST_LENGTH);
pwd_session->state = PWD_STATE_CONFIRM;
ret = send_pwd_request(pwd_session, eap_ds);
break;
case PWD_STATE_CONFIRM:
if (EAP_PWD_GET_EXCHANGE(hdr) != EAP_PWD_EXCH_CONFIRM) {
RDEBUG2("pwd exchange is incorrect: not commit!");
return 0;
}
if (compute_peer_confirm(pwd_session, peer_confirm, inst->bnctx)) {
RDEBUG2("pwd exchange cannot compute peer's confirm");
return 0;
}
if (memcmp(peer_confirm, buf, SHA256_DIGEST_LENGTH)) {
RDEBUG2("pwd exchange fails: peer confirm is incorrect!");
return 0;
}
if (compute_keys(pwd_session, peer_confirm, msk, emsk)) {
RDEBUG2("pwd exchange cannot generate (E)MSK!");
return 0;
}
eap_ds->request->code = PW_EAP_SUCCESS;
/*
* return the MSK (in halves)
*/
eap_add_reply(handler->request,
"MS-MPPE-Recv-Key", msk, MPPE_KEY_LEN);
eap_add_reply(handler->request,
"MS-MPPE-Send-Key", msk+MPPE_KEY_LEN, MPPE_KEY_LEN);
ret = 1;
break;
default:
RDEBUG2("unknown PWD state");
return 0;
}
/*
* we processed the buffered fragments, get rid of them
*/
if (pwd_session->in_buf) {
talloc_free(pwd_session->in_buf);
pwd_session->in_buf = NULL;
}
return ret;
}
static int mod_process(void *arg, eap_handler_t *handler)
{
pwd_session_t *session;
pwd_hdr *hdr;
pwd_id_packet_t *packet;
eap_packet_t *response;
REQUEST *request, *fake;
VALUE_PAIR *pw, *vp;
EAP_DS *eap_ds;
size_t in_len;
int ret = 0;
eap_pwd_t *inst = (eap_pwd_t *)arg;
uint16_t offset;
uint8_t exch, *in, *ptr, msk[MSK_EMSK_LEN], emsk[MSK_EMSK_LEN];
uint8_t peer_confirm[SHA256_DIGEST_LENGTH];
if (((eap_ds = handler->eap_ds) == NULL) || !inst) return 0;
session = (pwd_session_t *)handler->opaque;
request = handler->request;
response = handler->eap_ds->response;
hdr = (pwd_hdr *)response->type.data;
/*
* The header must be at least one byte.
*/
if (!hdr || (response->type.length < sizeof(pwd_hdr))) {
RDEBUG("Packet with insufficient data");
return 0;
}
in = hdr->data;
in_len = response->type.length - sizeof(pwd_hdr);
/*
* see if we're fragmenting, if so continue until we're done
*/
if (session->out_pos) {
if (in_len) RDEBUG2("pwd got something more than an ACK for a fragment");
return send_pwd_request(session, eap_ds);
}
/*
* the first fragment will have a total length, make a
* buffer to hold all the fragments
*/
if (EAP_PWD_GET_LENGTH_BIT(hdr)) {
if (session->in) {
RDEBUG2("pwd already alloced buffer for fragments");
return 0;
}
if (in_len < 2) {
RDEBUG("Invalid packet: length bit set, but no length field");
return 0;
}
session->in_len = ntohs(in[0] * 256 | in[1]);
if ((session->in = talloc_zero_array(session, uint8_t, session->in_len)) == NULL) {
RDEBUG2("pwd cannot allocate %zd buffer to hold fragments",
session->in_len);
return 0;
}
memset(session->in, 0, session->in_len);
session->in_pos = 0;
in += sizeof(uint16_t);
in_len -= sizeof(uint16_t);
}
/*
* all fragments, including the 1st will have the M(ore) bit set,
* buffer those fragments!
*/
if (EAP_PWD_GET_MORE_BIT(hdr)) {
rad_assert(session->in != NULL);
if ((session->in_pos + in_len) > session->in_len) {
RDEBUG2("Fragment overflows packet.");
return 0;
}
memcpy(session->in + session->in_pos, in, in_len);
session->in_pos += in_len;
/*
* send back an ACK for this fragment
*/
exch = EAP_PWD_GET_EXCHANGE(hdr);
eap_ds->request->code = PW_EAP_REQUEST;
eap_ds->request->type.num = PW_EAP_PWD;
eap_ds->request->type.length = sizeof(pwd_hdr);
if ((eap_ds->request->type.data = talloc_array(eap_ds->request, uint8_t, sizeof(pwd_hdr))) == NULL) {
return 0;
}
hdr = (pwd_hdr *)eap_ds->request->type.data;
EAP_PWD_SET_EXCHANGE(hdr, exch);
return 1;
}
if (session->in) {
/*
* the last fragment...
*/
if ((session->in_pos + in_len) > session->in_len) {
RDEBUG2("pwd will not overflow a fragment buffer. Nope, not prudent");
return 0;
}
memcpy(session->in + session->in_pos, in, in_len);
in = session->in;
in_len = session->in_len;
}
switch (session->state) {
case PWD_STATE_ID_REQ:
{
BIGNUM *x = NULL, *y = NULL;
if (EAP_PWD_GET_EXCHANGE(hdr) != EAP_PWD_EXCH_ID) {
RDEBUG2("pwd exchange is incorrect: not ID");
return 0;
}
packet = (pwd_id_packet_t *) in;
if (in_len < sizeof(*packet)) {
RDEBUG("Packet is too small (%zd < %zd).", in_len, sizeof(*packet));
return 0;
}
if ((packet->prf != EAP_PWD_DEF_PRF) ||
(packet->random_function != EAP_PWD_DEF_RAND_FUN) ||
(packet->prep != EAP_PWD_PREP_NONE) ||
(CRYPTO_memcmp(packet->token, &session->token, 4)) ||
(packet->group_num != ntohs(session->group_num))) {
RDEBUG2("pwd id response is invalid");
return 0;
}
/*
* we've agreed on the ciphersuite, record it...
*/
ptr = (uint8_t *)&session->ciphersuite;
memcpy(ptr, (char *)&packet->group_num, sizeof(uint16_t));
ptr += sizeof(uint16_t);
*ptr = EAP_PWD_DEF_RAND_FUN;
ptr += sizeof(uint8_t);
*ptr = EAP_PWD_DEF_PRF;
session->peer_id_len = in_len - sizeof(pwd_id_packet_t);
if (session->peer_id_len >= sizeof(session->peer_id)) {
RDEBUG2("pwd id response is malformed");
return 0;
}
memcpy(session->peer_id, packet->identity, session->peer_id_len);
session->peer_id[session->peer_id_len] = '\0';
/*
* make fake request to get the password for the usable ID
*/
if ((fake = request_alloc_fake(handler->request)) == NULL) {
RDEBUG("pwd unable to create fake request!");
return 0;
}
fake->username = fr_pair_afrom_num(fake->packet, PW_USER_NAME, 0);
if (!fake->username) {
RDEBUG("Failed creating pair for peer id");
talloc_free(fake);
return 0;
}
fr_pair_value_bstrncpy(fake->username, session->peer_id, session->peer_id_len);
fr_pair_add(&fake->packet->vps, fake->username);
if ((vp = fr_pair_find_by_num(request->config, PW_VIRTUAL_SERVER, 0, TAG_ANY)) != NULL) {
fake->server = vp->vp_strvalue;
} else if (inst->virtual_server) {
fake->server = inst->virtual_server;
} /* else fake->server == request->server */
RDEBUG("Sending tunneled request");
rdebug_pair_list(L_DBG_LVL_1, request, fake->packet->vps, NULL);
if (fake->server) {
RDEBUG("server %s {", fake->server);
} else {
RDEBUG("server {");
}
/*
* Call authorization recursively, which will
* get the password.
*/
RINDENT();
process_authorize(0, fake);
REXDENT();
/*
* Note that we don't do *anything* with the reply
* attributes.
*/
if (fake->server) {
RDEBUG("} # server %s", fake->server);
} else {
RDEBUG("}");
}
RDEBUG("Got tunneled reply code %d", fake->reply->code);
rdebug_pair_list(L_DBG_LVL_1, request, fake->reply->vps, NULL);
if ((pw = fr_pair_find_by_num(fake->config, PW_CLEARTEXT_PASSWORD, 0, TAG_ANY)) == NULL) {
DEBUG2("failed to find password for %s to do pwd authentication",
session->peer_id);
talloc_free(fake);
return 0;
}
if (compute_password_element(session, session->group_num,
pw->data.strvalue, strlen(pw->data.strvalue),
inst->server_id, strlen(inst->server_id),
session->peer_id, strlen(session->peer_id),
&session->token)) {
DEBUG2("failed to obtain password element");
talloc_free(fake);
return 0;
}
TALLOC_FREE(fake);
/*
* compute our scalar and element
*/
if (compute_scalar_element(session, inst->bnctx)) {
DEBUG2("failed to compute server's scalar and element");
return 0;
}
MEM(x = BN_new());
MEM(y = BN_new());
/*
* element is a point, get both coordinates: x and y
*/
if (!EC_POINT_get_affine_coordinates_GFp(session->group, session->my_element, x, y,
inst->bnctx)) {
DEBUG2("server point assignment failed");
BN_clear_free(x);
BN_clear_free(y);
return 0;
}
/*
* construct request
*/
session->out_len = BN_num_bytes(session->order) + (2 * BN_num_bytes(session->prime));
if ((session->out = talloc_array(session, uint8_t, session->out_len)) == NULL) {
return 0;
}
memset(session->out, 0, session->out_len);
ptr = session->out;
offset = BN_num_bytes(session->prime) - BN_num_bytes(x);
BN_bn2bin(x, ptr + offset);
BN_clear_free(x);
ptr += BN_num_bytes(session->prime);
offset = BN_num_bytes(session->prime) - BN_num_bytes(y);
BN_bn2bin(y, ptr + offset);
BN_clear_free(y);
ptr += BN_num_bytes(session->prime);
offset = BN_num_bytes(session->order) - BN_num_bytes(session->my_scalar);
BN_bn2bin(session->my_scalar, ptr + offset);
session->state = PWD_STATE_COMMIT;
ret = send_pwd_request(session, eap_ds);
}
break;
case PWD_STATE_COMMIT:
if (EAP_PWD_GET_EXCHANGE(hdr) != EAP_PWD_EXCH_COMMIT) {
RDEBUG2("pwd exchange is incorrect: not commit!");
return 0;
}
/*
* process the peer's commit and generate the shared key, k
*/
if (process_peer_commit(session, in, in_len, inst->bnctx)) {
RDEBUG2("failed to process peer's commit");
return 0;
}
/*
* compute our confirm blob
*/
if (compute_server_confirm(session, session->my_confirm, inst->bnctx)) {
ERROR("rlm_eap_pwd: failed to compute confirm!");
return 0;
}
/*
* construct a response...which is just our confirm blob
*/
session->out_len = SHA256_DIGEST_LENGTH;
if ((session->out = talloc_array(session, uint8_t, session->out_len)) == NULL) {
return 0;
}
memset(session->out, 0, session->out_len);
memcpy(session->out, session->my_confirm, SHA256_DIGEST_LENGTH);
session->state = PWD_STATE_CONFIRM;
ret = send_pwd_request(session, eap_ds);
break;
case PWD_STATE_CONFIRM:
if (in_len < SHA256_DIGEST_LENGTH) {
RDEBUG("Peer confirm is too short (%zd < %d)",
in_len, SHA256_DIGEST_LENGTH);
return 0;
}
if (EAP_PWD_GET_EXCHANGE(hdr) != EAP_PWD_EXCH_CONFIRM) {
RDEBUG2("pwd exchange is incorrect: not commit!");
return 0;
}
if (compute_peer_confirm(session, peer_confirm, inst->bnctx)) {
RDEBUG2("pwd exchange cannot compute peer's confirm");
return 0;
}
if (CRYPTO_memcmp(peer_confirm, in, SHA256_DIGEST_LENGTH)) {
RDEBUG2("pwd exchange fails: peer confirm is incorrect!");
return 0;
}
if (compute_keys(session, peer_confirm, msk, emsk)) {
RDEBUG2("pwd exchange cannot generate (E)MSK!");
return 0;
}
eap_ds->request->code = PW_EAP_SUCCESS;
/*
* return the MSK (in halves)
*/
eap_add_reply(handler->request, "MS-MPPE-Recv-Key", msk, MPPE_KEY_LEN);
eap_add_reply(handler->request, "MS-MPPE-Send-Key", msk + MPPE_KEY_LEN, MPPE_KEY_LEN);
ret = 1;
break;
default:
RDEBUG2("unknown PWD state");
return 0;
}
/*
* we processed the buffered fragments, get rid of them
*/
if (session->in) {
talloc_free(session->in);
session->in = NULL;
}
return ret;
}