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/*
* One-Time-Password (RFC 2444) authentication mechanism.
*
* Copyright (c) 2006 Andrey Panin <pazke@donpac.ru>
*
* This software is released under the MIT license.
*/
#include "auth-common.h"
#include "safe-memset.h"
#include "hash.h"
#include "mech.h"
#include "passdb.h"
#include "hex-binary.h"
#include "otp.h"
#include "mech-otp-common.h"
static void
otp_send_challenge(struct auth_request *auth_request,
const unsigned char *credentials, size_t size)
{
struct otp_auth_request *request =
(struct otp_auth_request *)auth_request;
const char *answer;
if (otp_parse_dbentry(t_strndup(credentials, size),
&request->state) != 0) {
e_error(request->auth_request.mech_event,
"invalid OTP data in passdb");
auth_request_fail(auth_request);
return;
}
if (--request->state.seq < 1) {
e_error(request->auth_request.mech_event,
"sequence number < 1");
auth_request_fail(auth_request);
return;
}
request->lock = otp_try_lock(auth_request);
if (!request->lock) {
e_error(request->auth_request.mech_event,
"user is locked, race attack?");
auth_request_fail(auth_request);
return;
}
answer = p_strdup_printf(request->pool, "otp-%s %u %s ext",
digest_name(request->state.algo),
request->state.seq, request->state.seed);
auth_request_handler_reply_continue(auth_request, answer,
strlen(answer));
}
static void
otp_credentials_callback(enum passdb_result result,
const unsigned char *credentials, size_t size,
struct auth_request *auth_request)
{
switch (result) {
case PASSDB_RESULT_OK:
otp_send_challenge(auth_request, credentials, size);
break;
case PASSDB_RESULT_INTERNAL_FAILURE:
auth_request_internal_failure(auth_request);
break;
default:
auth_request_fail(auth_request);
break;
}
}
static void
mech_otp_auth_phase1(struct auth_request *auth_request,
const unsigned char *data, size_t data_size)
{
struct otp_auth_request *request =
(struct otp_auth_request *)auth_request;
const char *authenid, *error;
size_t i, count;
/* authorization ID \0 authentication ID
FIXME: we'll ignore authorization ID for now. */
authenid = NULL;
count = 0;
for (i = 0; i < data_size; i++) {
if (data[i] == '\0') {
if (++count == 1)
authenid = (const char *) data + i + 1;
}
}
if (count != 1) {
e_error(request->auth_request.mech_event,
"invalid input");
auth_request_fail(auth_request);
return;
}
if (!auth_request_set_username(auth_request, authenid, &error)) {
e_info(auth_request->mech_event, "%s", error);
auth_request_fail(auth_request);
return;
}
auth_request_lookup_credentials(auth_request, "OTP",
otp_credentials_callback);
}
static void mech_otp_verify(struct auth_request *auth_request,
const char *data, bool hex)
{
struct otp_auth_request *request =
(struct otp_auth_request *)auth_request;
struct otp_state *state = &request->state;
unsigned char hash[OTP_HASH_SIZE], cur_hash[OTP_HASH_SIZE];
int ret;
ret = otp_parse_response(data, hash, hex);
if (ret < 0) {
e_error(request->auth_request.mech_event,
"invalid response");
auth_request_fail(auth_request);
otp_unlock(auth_request);
return;
}
otp_next_hash(state->algo, hash, cur_hash);
ret = memcmp(cur_hash, state->hash, OTP_HASH_SIZE);
if (ret != 0) {
auth_request_fail(auth_request);
otp_unlock(auth_request);
return;
}
memcpy(state->hash, hash, sizeof(state->hash));
auth_request_set_credentials(auth_request, "OTP",
otp_print_dbentry(state),
otp_set_credentials_callback);
}
static void mech_otp_verify_init(struct auth_request *auth_request,
const char *data, bool hex)
{
struct otp_auth_request *request =
(struct otp_auth_request *)auth_request;
struct otp_state new_state;
unsigned char hash[OTP_HASH_SIZE], cur_hash[OTP_HASH_SIZE];
const char *error;
int ret;
ret = otp_parse_init_response(data, &new_state, cur_hash, hex, &error);
if (ret < 0) {
e_error(request->auth_request.mech_event,
"invalid init response, %s", error);
auth_request_fail(auth_request);
otp_unlock(auth_request);
return;
}
otp_next_hash(request->state.algo, cur_hash, hash);
ret = memcmp(hash, request->state.hash, OTP_HASH_SIZE);
if (ret != 0) {
auth_request_fail(auth_request);
otp_unlock(auth_request);
return;
}
auth_request_set_credentials(auth_request, "OTP",
otp_print_dbentry(&new_state),
otp_set_credentials_callback);
}
static void
mech_otp_auth_phase2(struct auth_request *auth_request,
const unsigned char *data, size_t data_size)
{
const char *str = t_strndup(data, data_size);
if (str_begins(str, "hex:")) {
mech_otp_verify(auth_request, str + 4, TRUE);
} else if (str_begins(str, "word:")) {
mech_otp_verify(auth_request, str + 5, FALSE);
} else if (str_begins(str, "init-hex:")) {
mech_otp_verify_init(auth_request, str + 9, TRUE);
} else if (str_begins(str, "init-word:")) {
mech_otp_verify_init(auth_request, str + 10, FALSE);
} else {
e_error(auth_request->mech_event,
"unsupported response type");
auth_request_fail(auth_request);
otp_unlock(auth_request);
}
}
static void
mech_otp_auth_continue(struct auth_request *auth_request,
const unsigned char *data, size_t data_size)
{
if (auth_request->fields.user == NULL) {
mech_otp_auth_phase1(auth_request, data, data_size);
} else {
mech_otp_auth_phase2(auth_request, data, data_size);
}
}
static struct auth_request *mech_otp_auth_new(void)
{
struct otp_auth_request *request;
pool_t pool;
otp_lock_init();
pool = pool_alloconly_create(MEMPOOL_GROWING"otp_auth_request", 2048);
request = p_new(pool, struct otp_auth_request, 1);
request->pool = pool;
request->lock = FALSE;
request->auth_request.refcount = 1;
request->auth_request.pool = pool;
return &request->auth_request;
}
const struct mech_module mech_otp = {
"OTP",
.flags = MECH_SEC_DICTIONARY | MECH_SEC_ACTIVE | MECH_SEC_ALLOW_NULS,
.passdb_need = MECH_PASSDB_NEED_SET_CREDENTIALS,
mech_otp_auth_new,
mech_generic_auth_initial,
mech_otp_auth_continue,
mech_otp_auth_free
};
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