692 lines
22 KiB
C
692 lines
22 KiB
C
/*
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* libZRTP SDK library, implements the ZRTP secure VoIP protocol.
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* Copyright (c) 2006-2009 Philip R. Zimmermann. All rights reserved.
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* Contact: http://philzimmermann.com
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* For licensing and other legal details, see the file zrtp_legal.c.
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*
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* Viktor Krykun <v.krikun at zfoneproject.com>
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*/
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#include "zrtp.h"
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#define _ZTU_ "zrtp mitm"
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extern zrtp_status_t _zrtp_machine_process_goclear(zrtp_stream_t* stream, zrtp_rtp_info_t* packet);
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/*===========================================================================*/
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/* State-Machine related functions */
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/*===========================================================================*/
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/*---------------------------------------------------------------------------*/
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static void _send_and_resend_sasrelay(zrtp_stream_t *stream, zrtp_retry_task_t* task)
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{
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if (task->_retrys >= ZRTP_T2_MAX_COUNT) {
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ZRTP_LOG(1,(_ZTU_,"WARNING! SASRELAY Max retransmissions count reached. ID=%u\n", stream->id));
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_zrtp_machine_enter_initiatingerror(stream, zrtp_error_timeout, 0);
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} else if (task->_is_enabled) {
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zrtp_status_t s = _zrtp_packet_send_message(stream, ZRTP_SASRELAY, &stream->messages.sasrelay);
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task->timeout = _zrtp_get_timeout((uint32_t)task->timeout, ZRTP_SASRELAY);
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if (zrtp_status_ok == s) {
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task->_retrys++;
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}
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if (stream->zrtp->cb.sched_cb.on_call_later) {
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stream->zrtp->cb.sched_cb.on_call_later(stream, task);
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}
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}
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}
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/*----------------------------------------------------------------------------*/
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static zrtp_status_t _create_sasrelay( zrtp_stream_t *stream,
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zrtp_sas_id_t transf_sas_scheme,
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zrtp_string32_t* transf_sas_value,
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uint8_t transf_ac_flag,
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uint8_t transf_d_flag,
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zrtp_packet_SASRelay_t* sasrelay )
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{
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zrtp_session_t *session = stream->session;
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zrtp_status_t s = zrtp_status_fail;
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void* cipher_ctx = NULL;
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/* (padding + sig_len + flags) + SAS scheme and SASHash */
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const uint8_t encrypted_body_size = (2 + 1 + 1) + 4 + 32;
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zrtp_memset(sasrelay, 0, sizeof(zrtp_packet_SASRelay_t));
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/* generate a random initialization vector for CFB cipher */
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if (ZRTP_CFBIV_SIZE != zrtp_randstr(session->zrtp, sasrelay->iv, ZRTP_CFBIV_SIZE)) {
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return zrtp_status_rp_fail;
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}
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sasrelay->flags |= (session->profile.disclose_bit || transf_d_flag) ? 0x01 : 0x00;
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sasrelay->flags |= (session->profile.allowclear && transf_ac_flag) ? 0x02 : 0x00;
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sasrelay->flags |= 0x04;
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zrtp_memcpy( sasrelay->sas_scheme,
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zrtp_comp_id2type(ZRTP_CC_SAS, transf_sas_scheme),
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ZRTP_COMP_TYPE_SIZE );
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if (transf_sas_value)
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zrtp_memcpy(sasrelay->sashash, transf_sas_value->buffer, transf_sas_value->length);
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/* Then we need to encrypt Confirm before computing Hmac. Use AES CFB */
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do {
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cipher_ctx = session->blockcipher->start( session->blockcipher,
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(uint8_t*)stream->cc.zrtp_key.buffer,
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NULL,
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ZRTP_CIPHER_MODE_CFB );
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if (!cipher_ctx) {
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break;
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}
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s = session->blockcipher->set_iv( session->blockcipher,
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cipher_ctx,
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(zrtp_v128_t*)sasrelay->iv);
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if (zrtp_status_ok != s) {
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break;
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}
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s = session->blockcipher->encrypt( session->blockcipher,
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cipher_ctx,
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(uint8_t*)sasrelay->pad,
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encrypted_body_size );
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} while(0);
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if (cipher_ctx) {
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session->blockcipher->stop(session->blockcipher, cipher_ctx);
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}
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if (zrtp_status_ok != s) {
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ZRTP_LOG(1,(_ZTU_,"\tERROR! Failed to encrypt SASRELAY Message status=%d. ID=%u\n", s, stream->id));
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return s;
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}
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/* Compute Hmac over encrypted part of Confirm */
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{
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zrtp_string128_t hmac = ZSTR_INIT_EMPTY(hmac);
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s = session->hash->hmac_c( session->hash,
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stream->cc.hmackey.buffer,
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stream->cc.hmackey.length,
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(const char*)&sasrelay->pad,
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encrypted_body_size,
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ZSTR_GV(hmac) );
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if (zrtp_status_ok != s) {
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ZRTP_LOG(1,(_ZTU_,"\tERROR! Failed to compute CONFIRM hmac status=%d. ID=%u\n", s, stream->id));
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return s;
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}
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zrtp_memcpy(sasrelay->hmac, hmac.buffer, ZRTP_HMAC_SIZE);
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}
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return s;
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}
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/*----------------------------------------------------------------------------*/
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zrtp_status_t _zrtp_machine_process_sasrelay(zrtp_stream_t *stream, zrtp_rtp_info_t *packet)
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{
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zrtp_session_t *session = stream->session;
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zrtp_packet_SASRelay_t *sasrelay = (zrtp_packet_SASRelay_t*) packet->message;
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void* cipher_ctx = NULL;
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zrtp_sas_id_t rendering_id = ZRTP_COMP_UNKN;
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zrtp_status_t s = zrtp_status_fail;
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zrtp_string128_t hmac = ZSTR_INIT_EMPTY(hmac);
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char zerosashash[32];
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unsigned sas_scheme_did_change = 0;
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unsigned sas_hash_did_change = 0;
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/* (padding + sig_len + flags) + SAS scheme and SAS hash */
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const uint8_t encrypted_body_size = (2 + 1 + 1) + 4 + 32;
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zrtp_memset(zerosashash, 0, sizeof(zerosashash));
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/* Check if the remote endpoint is assigned to relay the SAS values */
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if (!stream->peer_mitm_flag) {
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ZRTP_LOG(2,(_ZTU_, ZRTP_RELAYED_SAS_FROM_NONMITM_STR));
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return zrtp_status_fail;
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}
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/* Check the HMAC */
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s = session->hash->hmac_c( session->hash,
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stream->cc.peer_hmackey.buffer,
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stream->cc.peer_hmackey.length,
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(const char*)&sasrelay->pad,
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encrypted_body_size,
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ZSTR_GV(hmac) );
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if (zrtp_status_ok != s ) {
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ZRTP_LOG(1,(_ZTU_,"\tERROR! Failed to compute CONFIRM hmac. status=%d ID=%u\n", s, stream->id));
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return zrtp_status_fail;
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}
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if (0 != zrtp_memcmp(sasrelay->hmac, hmac.buffer, ZRTP_HMAC_SIZE)) {
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ZRTP_LOG(2,(_ZTU_, ZRTP_VERIFIED_RESP_WARNING_STR));
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return zrtp_status_fail;
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}
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ZRTP_LOG(3,(_ZTU_, "\tHMAC value for the SASRELAY is correct - decrypting...\n"));
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/* Then we need to decrypt Confirm body */
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do
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{
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cipher_ctx = session->blockcipher->start( session->blockcipher,
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(uint8_t*)stream->cc.peer_zrtp_key.buffer,
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NULL,
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ZRTP_CIPHER_MODE_CFB );
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if (!cipher_ctx) {
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break;
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}
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s = session->blockcipher->set_iv(session->blockcipher, cipher_ctx, (zrtp_v128_t*)sasrelay->iv);
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if (zrtp_status_ok != s) {
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break;
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}
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s = session->blockcipher->decrypt( session->blockcipher,
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cipher_ctx,
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(uint8_t*)sasrelay->pad,
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encrypted_body_size);
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} while(0);
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if (cipher_ctx) {
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session->blockcipher->stop(session->blockcipher, cipher_ctx);
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}
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if (zrtp_status_ok != s) {
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ZRTP_LOG(1,(_ZTU_,"\tERROR! Failed to decrypt Confirm. status=%d ID=%u\n", s, stream->id));
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return s;
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}
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ZRTP_LOG(2,(_ZTU_,"\tSasRelay FLAGS old/new A=%d/%d, D=%d/%d.\n",
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stream->allowclear, (uint8_t)(sasrelay->flags & 0x02),
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stream->peer_disclose_bit, (uint8_t)(sasrelay->flags & 0x01)));
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/* Set evil bit if other-side disclosed session key */
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stream->peer_disclose_bit = (sasrelay->flags & 0x01);
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/* Enable ALLOWCLEAR option only if both sides support it */
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stream->allowclear = (sasrelay->flags & 0x02) && session->profile.allowclear;
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/*
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* We don't handle verified flag in SASRelaying because it makes no
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* sense in implementation of the ZRTP Internet Draft.
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*/
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/*
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* Only enrolled users can do SAS transferring. (Non-enrolled users can
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* only change the SAS rendering scheme).
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*/
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rendering_id = zrtp_comp_type2id(ZRTP_CC_SAS, (char*)sasrelay->sas_scheme);
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if (-1 == zrtp_profile_find(&session->profile, ZRTP_CC_SAS, rendering_id)) {
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ZRTP_LOG(1,(_ZTU_,"\tERROR! PBX Confirm packet with transferred SAS have unknown or"
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" unsupported rendering scheme %.4s.ID=%u\n", sasrelay->sas_scheme, stream->id));
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_zrtp_machine_enter_initiatingerror(stream, zrtp_error_invalid_packet, 1);
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return zrtp_status_fail;
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}
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/* Check is SAS rendering did change */
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if (rendering_id != session->sasscheme->base.id) {
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session->sasscheme = zrtp_comp_find(ZRTP_CC_SAS, rendering_id, session->zrtp );
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sas_scheme_did_change = 1;
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ZRTP_LOG(3,(_ZTU_,"\tSasrelay: Rendering scheme was updated to %.4s.\n", session->sasscheme->base.type));
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}
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if (session->secrets.matches & ZRTP_BIT_PBX) {
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if ( (((uint32_t) *sasrelay->sas_scheme) != (uint32_t)0x0L) &&
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(0 != zrtp_memcmp(sasrelay->sashash, zerosashash, sizeof(sasrelay->sashash))) )
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{
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char buff[256];
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session->sasbin.length = ZRTP_MITM_SAS_SIZE;
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/* First 32 bits if sashash includes sasvalue */
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zrtp_memcpy(session->sasbin.buffer, sasrelay->sashash, session->sasbin.length);
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stream->mitm_mode = ZRTP_MITM_MODE_RECONFIRM_CLIENT;
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sas_hash_did_change = 1;
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ZRTP_LOG(3,(_ZTU_,"\tSasRelay: SAS value was updated to bin=%s.\n",
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hex2str(session->sasbin.buffer, session->sasbin.length, buff, sizeof(buff))));
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}
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} else if (0 != zrtp_memcmp(sasrelay->sashash, zerosashash, sizeof(sasrelay->sashash))) {
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ZRTP_LOG(1,(_ZTU_,"\tWARNING! SAS Value was received from NOT Trusted MiTM. ID=%u\n", stream->id));
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_zrtp_machine_enter_initiatingerror(stream, zrtp_error_possible_mitm3, 1);
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return zrtp_status_fail;
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} else {
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ZRTP_LOG(1,(_ZTU_, "\rERROR! For SasRelay Other secret doesn't match. ID=%u\n", stream->id));
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}
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/* Generate new SAS if hash or rendering scheme did change.
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* Note: latest libzrtp may send "empty" SasRelay with the same SAS rendering
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* scheme and empty Hello hash for consistency reasons, we should ignore
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* such packets.
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*/
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if (sas_scheme_did_change || sas_hash_did_change) {
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s = session->sasscheme->compute(session->sasscheme, stream, session->hash, 1);
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if (zrtp_status_ok != s) {
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_zrtp_machine_enter_initiatingerror(stream, zrtp_error_software, 1);
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return s;
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}
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ZRTP_LOG(3,(_ZTU_,"\tSasRelay: Updated SAS is <%s> <%s>.\n", session->sas1.buffer, session->sas2.buffer));
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if (session->zrtp->cb.event_cb.on_zrtp_protocol_event) {
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session->zrtp->cb.event_cb.on_zrtp_protocol_event(stream, ZRTP_EVENT_LOCAL_SAS_UPDATED);
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}
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}
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return zrtp_status_ok;
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}
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/*---------------------------------------------------------------------------*/
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zrtp_status_t _zrtp_machine_process_while_in_sasrelaying( zrtp_stream_t* stream,
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zrtp_rtp_info_t* packet)
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{
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zrtp_status_t s = zrtp_status_ok;
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switch (packet->type)
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{
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case ZRTP_RELAYACK:
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_zrtp_cancel_send_packet_later(stream, ZRTP_SASRELAY);
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_zrtp_change_state(stream, ZRTP_STATE_SECURE);
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if (stream->zrtp->cb.event_cb.on_zrtp_protocol_event) {
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stream->zrtp->cb.event_cb.on_zrtp_protocol_event(stream, ZRTP_EVENT_REMOTE_SAS_UPDATED);
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}
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break;
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case ZRTP_GOCLEAR:
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s = _zrtp_machine_process_goclear(stream, packet);
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if (zrtp_status_ok == s) {
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s = _zrtp_machine_enter_pendingclear(stream);
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}
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break;
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case ZRTP_NONE:
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s = _zrtp_protocol_decrypt(stream->protocol, packet, 1);
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break;
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default:
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break;
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}
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return s;
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}
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/*===========================================================================*/
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/* ZRTP API for PBX */
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/*===========================================================================*/
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/*---------------------------------------------------------------------------*/
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zrtp_status_t zrtp_stream_registration_start(zrtp_stream_t* stream, uint32_t ssrc)
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{
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if (!stream) {
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return zrtp_status_bad_param;
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}
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ZRTP_LOG(3,(_ZTU_,"START REGISTRATION STREAM ID=%u mode=%s state=%s.\n",
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stream->id, zrtp_log_mode2str(stream->mode), zrtp_log_state2str(stream->state)));
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if (NULL == stream->zrtp->cb.cache_cb.on_get_mitm) {
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ZRTP_LOG(2,(_ZTU_,"WARNING: Can't use MiTM Functions with no ZRTP Cache.\n"));
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return zrtp_status_notavailable;
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}
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stream->mitm_mode = ZRTP_MITM_MODE_REG_SERVER;
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return zrtp_stream_start(stream, ssrc);
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}
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zrtp_status_t zrtp_stream_registration_secure(zrtp_stream_t* stream)
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{
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if (!stream) {
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return zrtp_status_bad_param;
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}
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ZRTP_LOG(3,(_ZTU_,"SECURE REGISTRATION STREAM ID=%u mode=%s state=%s.\n",
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stream->id, zrtp_log_mode2str(stream->mode), zrtp_log_state2str(stream->state)));
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if (NULL == stream->zrtp->cb.cache_cb.on_get_mitm) {
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ZRTP_LOG(2,(_ZTU_,"WARNING: Can't use MiTM Functions with no ZRTP Cache.\n"));
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return zrtp_status_notavailable;
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}
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stream->mitm_mode = ZRTP_MITM_MODE_REG_SERVER;
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return zrtp_stream_secure(stream);
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}
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/*---------------------------------------------------------------------------*/
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zrtp_status_t zrtp_register_with_trusted_mitm(zrtp_stream_t* stream)
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{
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zrtp_session_t *session = stream->session;
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zrtp_status_t s = zrtp_status_bad_param;
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if (!stream) {
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return zrtp_status_bad_param;
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}
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ZRTP_LOG(3,(_ZTU_,"MARKING this call as REGISTRATION ID=%u\n", stream->id));
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if (NULL == stream->zrtp->cb.cache_cb.on_get_mitm) {
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ZRTP_LOG(2,(_ZTU_,"WARNING: Can't use MiTM Functions with no ZRTP Cache.\n"));
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return zrtp_status_notavailable;
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}
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if (!stream->protocol) {
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return zrtp_status_bad_param;
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}
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/* Passive Client endpoint should NOT generate PBX Secret. */
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if ((stream->mitm_mode == ZRTP_MITM_MODE_REG_CLIENT) &&
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(ZRTP_LICENSE_MODE_PASSIVE == stream->zrtp->lic_mode)) {
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ZRTP_LOG(2,(_ZTU_,"WARNING: Passive Client endpoint should NOT generate PBX Secret.\n"));
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return zrtp_status_bad_param;
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}
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/*
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* Generate new MitM cache:
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* pbxsecret = KDF(ZRTPSess, "Trusted MiTM key", (ZIDi | ZIDr), negotiated hash length)
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*/
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if ( (stream->state == ZRTP_STATE_SECURE) &&
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((stream->mitm_mode == ZRTP_MITM_MODE_REG_CLIENT) || (stream->mitm_mode == ZRTP_MITM_MODE_REG_SERVER)) )
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{
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zrtp_string32_t kdf_context = ZSTR_INIT_EMPTY(kdf_context);
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static const zrtp_string32_t trusted_mitm_key_label = ZSTR_INIT_WITH_CONST_CSTRING(ZRTP_TRUSTMITMKEY_STR);
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zrtp_string16_t *zidi, *zidr;
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if (stream->protocol->type == ZRTP_STATEMACHINE_INITIATOR) {
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zidi = &session->zid;
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zidr = &session->peer_zid;
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} else {
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zidi = &session->peer_zid;
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zidr = &session->zid;
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}
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zrtp_zstrcat(ZSTR_GV(kdf_context), ZSTR_GVP(zidi));
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zrtp_zstrcat(ZSTR_GV(kdf_context), ZSTR_GVP(zidr));
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_zrtp_kdf( stream,
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ZSTR_GV(session->zrtpsess),
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ZSTR_GV(trusted_mitm_key_label),
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ZSTR_GV(kdf_context),
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ZRTP_HASH_SIZE,
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ZSTR_GV(session->secrets.pbxs->value));
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session->secrets.pbxs->_cachedflag = 1;
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session->secrets.pbxs->lastused_at = (uint32_t)(zrtp_time_now()/1000);
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session->secrets.cached |= ZRTP_BIT_PBX;
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session->secrets.matches |= ZRTP_BIT_PBX;
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s = zrtp_status_ok;
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if (session->zrtp->cb.cache_cb.on_put_mitm) {
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s = session->zrtp->cb.cache_cb.on_put_mitm( ZSTR_GV(session->zid),
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ZSTR_GV(session->peer_zid),
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session->secrets.pbxs);
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}
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ZRTP_LOG(3,(_ZTU_,"Makring this call as REGISTRATION - DONE\n"));
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}
|
|
|
|
return s;
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
zrtp_status_t zrtp_link_mitm_calls(zrtp_stream_t *stream1, zrtp_stream_t *stream2)
|
|
{
|
|
if (!stream1 || !stream2) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
ZRTP_LOG(3,(_ZTU_,"Link to MiTM call together stream1=%u stream2=%u.\n", stream1->id, stream2->id));
|
|
|
|
/* This APi is for MiTM endpoints only. */
|
|
if (stream1->zrtp->is_mitm) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
stream1->linked_mitm = stream2;
|
|
stream2->linked_mitm = stream1;
|
|
|
|
{
|
|
zrtp_stream_t *passive = NULL;
|
|
zrtp_stream_t *unlimited = NULL;
|
|
|
|
/* Check if we have at least one Unlimited endpoint. */
|
|
if (stream1->peer_super_flag)
|
|
unlimited = stream1;
|
|
else if (stream2->peer_super_flag)
|
|
unlimited = stream2;
|
|
|
|
/* Check if the peer stream is Passive */
|
|
if (unlimited) {
|
|
passive = (stream1 == unlimited) ? stream2 : stream1;
|
|
if (!passive->peer_passive)
|
|
passive = NULL;
|
|
}
|
|
|
|
/* Ok, we haver Unlimited and Passive at two ends, let's make an exception and switch Passive to Secure. */
|
|
if (unlimited && passive) {
|
|
if (passive->state == ZRTP_STATE_CLEAR) {
|
|
ZRTP_LOG(2,(_ZTU_,"INFO: zrtp_link_mitm_calls() stream with id=%u is Unlimited and"
|
|
" Peer stream with id=%u is Passive in CLEAR state, switch the passive one to SECURE.\n"));
|
|
|
|
/* @note: don't use zrtp_secure_stream() wrapper as it checks for Active/Passive stuff. */
|
|
_zrtp_machine_start_initiating_secure(passive);
|
|
}
|
|
}
|
|
}
|
|
|
|
return zrtp_status_ok;
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
zrtp_status_t zrtp_update_remote_options( zrtp_stream_t* stream,
|
|
zrtp_sas_id_t transf_sas_scheme,
|
|
zrtp_string32_t* transf_sas_value,
|
|
uint8_t transf_ac_flag,
|
|
uint8_t transf_d_flag )
|
|
{
|
|
zrtp_retry_task_t* task = &stream->messages.sasrelay_task;
|
|
zrtp_status_t s = zrtp_status_ok;
|
|
char buff[256];
|
|
|
|
if (!stream) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
ZRTP_LOG(3,(_ZTU_,"UPDATE REMOTE SAS OPTIONS mode. ID=%u\n", stream->id));
|
|
ZRTP_LOG(3,(_ZTU_,"transf_sas=%s scheme=%d.\n", transf_sas_value ?
|
|
hex2str((const char*)transf_sas_value->buffer, transf_sas_value->length, (char*)buff, sizeof(buff)) : "NULL",
|
|
transf_sas_scheme));
|
|
|
|
if (NULL == stream->zrtp->cb.cache_cb.on_get_mitm) {
|
|
ZRTP_LOG(2,(_ZTU_,"WARNING: Can't use MiTM Functions with no ZRTP Cache.\n"));
|
|
return zrtp_status_notavailable;
|
|
}
|
|
|
|
/* The TRANSFERRING option is only available from the SECURE state. */
|
|
if (stream->state != ZRTP_STATE_SECURE) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
/* Don't transfer an SAS to a non-enrolled user */
|
|
if (transf_sas_value && !(stream->session->secrets.matches & ZRTP_BIT_PBX)) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
/* Don't allow to transfer the SAS if the library wasn't initialized as MiTM endpoint */
|
|
if (!stream->zrtp->is_mitm) {
|
|
ZRTP_LOG(3,(_ZTU_,"\tERROR! The endpoint can't transfer SAS values to other endpoints"
|
|
" without introducing itself by M-flag in Hello. see zrtp_init().\n"));
|
|
return zrtp_status_wrong_state;
|
|
}
|
|
|
|
s = _create_sasrelay( stream,
|
|
transf_sas_scheme,
|
|
transf_sas_value,
|
|
transf_ac_flag,
|
|
transf_d_flag,
|
|
&stream->messages.sasrelay);
|
|
if(zrtp_status_ok != s) {
|
|
return s;
|
|
}
|
|
|
|
s = _zrtp_packet_fill_msg_hdr( stream,
|
|
ZRTP_SASRELAY,
|
|
sizeof(zrtp_packet_SASRelay_t) - sizeof(zrtp_msg_hdr_t),
|
|
&stream->messages.sasrelay.hdr);
|
|
if(zrtp_status_ok != s) {
|
|
return s;
|
|
}
|
|
|
|
_zrtp_change_state(stream, ZRTP_STATE_SASRELAYING);
|
|
|
|
task->_is_enabled = 1;
|
|
task->callback = _send_and_resend_sasrelay;
|
|
task->_retrys = 0;
|
|
_send_and_resend_sasrelay(stream, task);
|
|
|
|
return s;
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
zrtp_status_t zrtp_resolve_mitm_call( zrtp_stream_t* stream1,
|
|
zrtp_stream_t* stream2)
|
|
{
|
|
zrtp_stream_t* enrolled = NULL;
|
|
zrtp_stream_t* non_enrolled = NULL;
|
|
zrtp_sas_id_t mitm_sas_scheme = ZRTP_COMP_UNKN;
|
|
zrtp_status_t s = zrtp_status_ok;
|
|
|
|
if (!stream1 || !stream2) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
ZRTP_LOG(3,(_ZTU_,"RESOLVE MITM CALL s1=%u, s2=%u...\n", stream1->id, stream2->id));
|
|
|
|
if (NULL == stream1->zrtp->cb.cache_cb.on_get_mitm) {
|
|
ZRTP_LOG(2,(_ZTU_,"WARNING: Can't use MiTM Functions with no ZRTP Cache.\n"));
|
|
return zrtp_status_notavailable;
|
|
}
|
|
|
|
/*
|
|
* Both sides must be in the Secure state and at least one should be
|
|
* enrolled.
|
|
*/
|
|
if ((stream1->state != ZRTP_STATE_SECURE) || (stream2->state != ZRTP_STATE_SECURE)) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
/* Check the stream enrollment options and choose one for transferring the call. */
|
|
if (zrtp_is_user_enrolled(stream1)) {
|
|
if (zrtp_is_user_enrolled(stream2)) {
|
|
ZRTP_LOG(3,(_ZTU_,"\tBoth streams are enrolled - choose one with bigger ZID.\n"));
|
|
enrolled = zrtp_choose_one_enrolled(stream1, stream2);
|
|
} else {
|
|
enrolled = stream1;
|
|
}
|
|
} else if (zrtp_is_user_enrolled(stream2)) {
|
|
enrolled = stream2;
|
|
}
|
|
|
|
if (!enrolled) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
else {
|
|
non_enrolled = (stream1 == enrolled) ? stream2 : stream1;
|
|
}
|
|
|
|
ZRTP_LOG(3,(_ZTU_,"\tAfter Resolving: S1 is %s and S2 is %s.\n",
|
|
(stream1 == enrolled) ? "ENROLLED" : "NON-ENROLLED",
|
|
(stream2 == enrolled) ? "ENROLLED" : "NON-ENROLLED"));
|
|
|
|
/*
|
|
* Choose the best SAS rendering scheme supported by both peers. Find the
|
|
* stream that can change it.
|
|
*/
|
|
{
|
|
uint8_t i=0;
|
|
|
|
zrtp_packet_Hello_t *enhello = &enrolled->messages.peer_hello;
|
|
char *encp = (char*)enhello->comp + (enhello->hc +
|
|
enhello->cc +
|
|
enhello->ac +
|
|
enhello->kc)* ZRTP_COMP_TYPE_SIZE;
|
|
|
|
|
|
for (i=0; i<enhello->sc; i++, encp+=ZRTP_COMP_TYPE_SIZE)
|
|
{
|
|
uint8_t j=0;
|
|
zrtp_packet_Hello_t *nonenhello = &non_enrolled->messages.peer_hello;
|
|
char *nonencp = (char*)nonenhello->comp + (nonenhello->hc +
|
|
nonenhello->cc +
|
|
nonenhello->ac +
|
|
nonenhello->kc)* ZRTP_COMP_TYPE_SIZE;
|
|
|
|
for (j=0; j<nonenhello->sc; j++, nonencp+=ZRTP_COMP_TYPE_SIZE)
|
|
{
|
|
if (0 == zrtp_memcmp(encp, nonencp, ZRTP_COMP_TYPE_SIZE)) {
|
|
mitm_sas_scheme = zrtp_comp_type2id(ZRTP_CC_SAS, encp);
|
|
ZRTP_LOG(3,(_ZTU_,"\tMITM SAS scheme=%.4s was choosen.\n", encp));
|
|
break;
|
|
}
|
|
}
|
|
if (j != nonenhello->sc) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (ZRTP_COMP_UNKN == mitm_sas_scheme) {
|
|
ZRTP_LOG(1,(_ZTU_,"\tERROR! Can't find matched SAS schemes on MiTM Resolving.\n"
|
|
" s1=%u s2=$u", stream1->id, stream2->id));
|
|
return zrtp_status_algo_fail;
|
|
}
|
|
|
|
s = zrtp_update_remote_options( enrolled,
|
|
mitm_sas_scheme,
|
|
&non_enrolled->session->sasbin,
|
|
non_enrolled->allowclear,
|
|
non_enrolled->peer_disclose_bit );
|
|
if (zrtp_status_ok != s) {
|
|
return s;
|
|
}
|
|
|
|
/* NOTE: new request from Philip Zimmermann - always send SASRelay to BOTH parties. */
|
|
/* If non-enrolled party has SAS scheme different from chosen one - update */
|
|
/*if (non_enrolled->session->sasscheme->base.id != mitm_sas_scheme) { */
|
|
s = zrtp_update_remote_options( non_enrolled,
|
|
mitm_sas_scheme,
|
|
NULL,
|
|
enrolled->allowclear,
|
|
enrolled->peer_disclose_bit );
|
|
if (zrtp_status_ok != s) {
|
|
return s;
|
|
}
|
|
/*}*/
|
|
|
|
return s;
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
uint8_t zrtp_is_user_enrolled(zrtp_stream_t* stream)
|
|
{
|
|
if (!stream) {
|
|
return zrtp_status_bad_param;
|
|
}
|
|
|
|
return ( (stream->session->secrets.cached & ZRTP_BIT_PBX) &&
|
|
(stream->session->secrets.matches & ZRTP_BIT_PBX) );
|
|
}
|
|
|
|
zrtp_stream_t* zrtp_choose_one_enrolled(zrtp_stream_t* stream1, zrtp_stream_t* stream2)
|
|
{
|
|
if (!stream1 || !stream2) {
|
|
return NULL;
|
|
}
|
|
|
|
if (zrtp_memcmp( stream1->session->zid.buffer,
|
|
stream2->session->zid.buffer,
|
|
stream1->session->zid.length) > 0) {
|
|
return stream1;
|
|
} else {
|
|
return stream2;
|
|
}
|
|
}
|