154 lines
3.9 KiB
C
154 lines
3.9 KiB
C
/* SMS based token authentication for ad-hoc GSM networks */
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/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <stdio.h>
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#include <osmocore/talloc.h>
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#include <openbsc/signal.h>
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#include <openbsc/gsm_data.h>
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#include <openbsc/gsm_04_11.h>
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#include <openbsc/gsm_04_08.h>
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#include <openbsc/gsm_subscriber.h>
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#include <openbsc/chan_alloc.h>
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#include <openbsc/db.h>
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#define TOKEN_SMS_TEXT "HAR 2009 GSM. Register at http://har2009.gnumonks.org/ " \
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"Your IMSI is %s, auth token is %08X, phone no is %s."
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static char *build_sms_string(struct gsm_subscriber *subscr, u_int32_t token)
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{
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char *sms_str;
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unsigned int len;
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len = strlen(subscr->imsi) + 8 + strlen(TOKEN_SMS_TEXT);
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sms_str = talloc_size(tall_bsc_ctx, len);
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if (!sms_str)
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return NULL;
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snprintf(sms_str, len, TOKEN_SMS_TEXT, subscr->imsi, token,
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subscr->extension);
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sms_str[len-1] = '\0';
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return sms_str;
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}
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static int token_subscr_cb(unsigned int subsys, unsigned int signal,
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void *handler_data, void *signal_data)
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{
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struct gsm_subscriber *subscr = signal_data;
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struct gsm_sms *sms;
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int rc = 0;
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if (signal != S_SUBSCR_ATTACHED)
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return 0;
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if (subscr->net->auth_policy != GSM_AUTH_POLICY_TOKEN)
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return 0;
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if (subscr->flags & GSM_SUBSCRIBER_FIRST_CONTACT) {
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u_int32_t token;
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char *sms_str;
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/* we've seen this subscriber for the first time. */
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rc = db_subscriber_alloc_token(subscr, &token);
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if (rc != 0) {
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rc = -EIO;
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goto unauth;
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}
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sms_str = build_sms_string(subscr, token);
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if (!sms_str) {
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rc = -ENOMEM;
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goto unauth;
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}
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sms = sms_from_text(subscr, 0, sms_str);
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talloc_free(sms_str);
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if (!sms) {
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rc = -ENOMEM;
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goto unauth;
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}
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rc = gsm411_send_sms_subscr(subscr, sms);
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/* FIXME: else, delete the subscirber from database */
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unauth:
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/* make sure we don't allow him in again unless he clicks the web UI */
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subscr->authorized = 0;
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db_sync_subscriber(subscr);
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if (rc) {
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struct gsm_subscriber_connection *conn = connection_for_subscr(subscr);
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if (conn) {
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u_int8_t auth_rand[16];
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/* kick the subscriber off the network */
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gsm48_tx_mm_auth_req(conn, auth_rand, 0);
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gsm48_tx_mm_auth_rej(conn);
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/* FIXME: close the channel early ?*/
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//gsm48_send_rr_Release(lchan);
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}
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}
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}
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return rc;
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}
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static int token_sms_cb(unsigned int subsys, unsigned int signal,
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void *handler_data, void *signal_data)
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{
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struct sms_signal_data *sig = signal_data;
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struct gsm_sms *sms = sig->sms;;
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struct gsm_subscriber_connection *conn;
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u_int8_t auth_rand[16];
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if (signal != S_SMS_DELIVERED)
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return 0;
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/* these are not the droids we've been looking for */
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if (!sms->receiver ||
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!(sms->receiver->flags & GSM_SUBSCRIBER_FIRST_CONTACT))
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return 0;
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if (sms->receiver->net->auth_policy != GSM_AUTH_POLICY_TOKEN)
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return 0;
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conn = connection_for_subscr(sms->receiver);
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if (conn) {
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/* kick the subscriber off the network */
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gsm48_tx_mm_auth_req(conn, auth_rand, 0);
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gsm48_tx_mm_auth_rej(conn);
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/* FIXME: close the channel early ?*/
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//gsm48_send_rr_Release(lchan);
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}
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return 0;
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}
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//static __attribute__((constructor)) void on_dso_load_token(void)
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void on_dso_load_token(void)
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{
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register_signal_handler(SS_SUBSCR, token_subscr_cb, NULL);
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register_signal_handler(SS_SMS, token_sms_cb, NULL);
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}
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