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378da62ccb
With this in place enabling an additional crypto suite would only require two changes: - Adding GStreamer capability mapping - Add case in calls_srtp_parse_sdp_crypto_attribute()
868 lines
28 KiB
C
868 lines
28 KiB
C
/*
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* Copyright (C) 2022 Purism SPC
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*
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* This file is part of Calls.
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*
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* Calls is free software: you can redistribute it and/or modify it
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* under the terms of the GNU 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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* Calls is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Calls. If not, see <http://www.gnu.org/licenses/>.
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*
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* Author: Evangelos Ribeiro Tzaras <evangelos.tzaras@puri.sm>
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*
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* SPDX-License-Identifier: GPL-3.0-or-later
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*
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*/
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#include "calls-srtp-utils.h"
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#include "calls-util.h"
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#include <gio/gio.h>
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#include <sys/random.h>
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/**
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* SECTION:srtp-utils
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* @short_description: SRTP utilities for SDP parsing
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* @Title: CallsSrtpUtils
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*
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* Utilities for parsing and generating the crypto attribute
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* in SDP for SRTP use based on RFC 4568.
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*
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* Note that limitations of libsrtp are taken into account when checking validity
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* of the parsed attribute. These are:
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* A maximum of 16 keys,
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* key derivation rate must be 0,
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* lifetimes other than 2^48 (we actually ignore the specified lifetimes)
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*/
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/* The default used in libsrtp. No API to change this. See https://github.com/cisco/libsrtp/issues/588 */
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#define SRTP_DEFAULT_LIFETIME_POW2 48
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#define SRTP_MAX_LIFETIME_POW2 48
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/* The default used in libsrtp (and GstSrtpEnc/GstSrtpDec) */
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#define SRTP_DEFAULT_WINDOW_SIZE 128
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static gsize
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get_key_size_for_suite (calls_srtp_crypto_suite suite)
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{
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switch (suite) {
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case CALLS_SRTP_SUITE_AES_CM_128_SHA1_32:
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case CALLS_SRTP_SUITE_AES_CM_128_SHA1_80:
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return 30;
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case CALLS_SRTP_SUITE_AES_192_CM_SHA1_32:
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case CALLS_SRTP_SUITE_AES_192_CM_SHA1_80:
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return 38;
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case CALLS_SRTP_SUITE_AES_256_CM_SHA1_32:
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case CALLS_SRTP_SUITE_AES_256_CM_SHA1_80:
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return 46;
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case CALLS_SRTP_SUITE_AEAD_AES_128_GCM:
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return 28;
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case CALLS_SRTP_SUITE_AEAD_AES_256_GCM:
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return 44;
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case CALLS_SRTP_SUITE_UNKNOWN:
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default:
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return 0;
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}
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}
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static gboolean
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validate_crypto_attribute (calls_srtp_crypto_attribute *attr,
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GError **error)
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{
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guint expected_key_salt_length;
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gboolean need_mki;
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guint expected_mki_length = 0;
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calls_srtp_crypto_key_param *key_param;
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GSList *mki_list = NULL; /* for checking uniqueness of MKIs */
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GSList *key_list = NULL; /* for checking uniqueness of keys */
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if (!attr) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Attribute is NULL");
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return FALSE;
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}
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if (attr->tag <= 0 || attr->tag >= 1000000000) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Tag is not valid: %d", attr->tag);
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return FALSE;
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}
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expected_key_salt_length = get_key_size_for_suite (attr->crypto_suite);
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if (expected_key_salt_length == 0) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Crypto suite unknown");
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return FALSE;
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}
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/* at least one and a maximum of 16 key parameters */
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if (attr->n_key_params == 0 || attr->n_key_params > 16) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Must have between 1 and 16 keys, got %d", attr->n_key_params);
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return FALSE;
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}
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need_mki = attr->n_key_params > 1 ||
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attr->key_params[0].mki ||
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attr->key_params[0].mki_length;
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if (need_mki) {
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expected_mki_length = attr->key_params[0].mki_length;
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if (expected_mki_length == 0 ||
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expected_mki_length > 128) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"MKI length must be between 1 and 128, got %u",
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attr->key_params[0].mki_length);
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return FALSE;
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}
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}
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for (guint i = 0; i < attr->n_key_params; i++) {
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g_autofree guchar *key_salt = NULL;
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gsize key_salt_length;
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key_param = &attr->key_params[i];
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/* must have a key */
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if (!key_param->b64_keysalt) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"No key found in parameter %d", i);
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goto failed;
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}
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key_salt = g_base64_decode (key_param->b64_keysalt, &key_salt_length);
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/* key must have length consistent with suite */
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if (key_salt_length != expected_key_salt_length) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Key %d has length %" G_GSIZE_FORMAT ", but expected %d",
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i, key_salt_length, expected_key_salt_length);
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goto failed;
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}
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/* key must be unique */
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if (g_slist_find_custom (key_list,
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key_param->b64_keysalt,
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(GCompareFunc) g_strcmp0)) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Key %d is not unique: %s", i, key_param->b64_keysalt);
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goto failed;
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}
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key_list = g_slist_append (key_list, key_param->b64_keysalt);
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/* lifetime in range */
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if (key_param->lifetime_type == CALLS_SRTP_LIFETIME_AS_DECIMAL_NUMBER &&
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key_param->lifetime >= (1ULL << SRTP_MAX_LIFETIME_POW2)) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Lifetime of key %d out of bounds: Got %" G_GINT64_FORMAT " but maximum is 2^%d",
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i, key_param->lifetime, SRTP_MAX_LIFETIME_POW2);
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goto failed;
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}
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if (key_param->lifetime_type == CALLS_SRTP_LIFETIME_AS_POWER_OF_TWO &&
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key_param->lifetime >= SRTP_MAX_LIFETIME_POW2) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Lifetime of key %d out of bounds: Got 2^%" G_GINT64_FORMAT " but maximum is 2^%d",
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i, key_param->lifetime, SRTP_MAX_LIFETIME_POW2);
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goto failed;
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}
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/* if MKI length is set, it must be the same for all key parameters */
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if (need_mki) {
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if (key_param->mki_length != expected_mki_length) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"MKI length must be the same for all keys. Key %d has length %d but expected %d",
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i, key_param->mki_length, expected_mki_length);
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goto failed;
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}
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/* MKI must not have leading zero */
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if (key_param->mki == 0) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"No MKI set for key %d", i);
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goto failed;
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}
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/* MKI must be unique */
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if (g_slist_find (mki_list, GINT_TO_POINTER (key_param->mki))) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"MKI for key %d is not unique", i);
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goto failed;
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}
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mki_list = g_slist_append (mki_list, GINT_TO_POINTER (key_param->mki));
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}
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}
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/* check session parameters */
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/* libsrtp does only support kdr=0 */
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if (attr->kdr != 0) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Key derivation rate must be 0, got %d",
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attr->kdr);
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goto failed;
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}
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g_slist_free (mki_list);
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g_slist_free (key_list);
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return TRUE;
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failed:
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g_slist_free (mki_list);
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g_slist_free (key_list);
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return FALSE;
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}
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/**
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* calls_srtp_generate_key_salt:
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* @length: Desired length of random data
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*
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* Generate random data to be used as master key and master salt of desired length @length
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*
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* Returns: (transfer full): Random data to be used as key and salt in SRTP
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* or %NULL if failed. Free with g_free() when done.
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*/
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guchar *
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calls_srtp_generate_key_salt (gsize length)
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{
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g_autofree guchar *key_salt = NULL;
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gsize n_bytes;
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g_return_val_if_fail (length > 0, NULL);
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key_salt = g_malloc (length);
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n_bytes = getrandom (key_salt, length, GRND_NONBLOCK);
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if (n_bytes == -1) {
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return NULL;
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}
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return g_steal_pointer (&key_salt);
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}
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/**
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* calls_srtp_generate_key_salt_for_suite:
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* @suite: a #calls_srtp_crypto_suite
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*
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* Generate random data to be used as master key and master salt.
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* The required length is determined by the requirements of the @suite
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*
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* Returns: (transfer full): Random data to be used as key and salt in SRTP
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* or %NULL if failed. Free with g_free() when done.
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*/
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guchar *
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calls_srtp_generate_key_salt_for_suite (calls_srtp_crypto_suite suite)
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{
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gsize size = get_key_size_for_suite (suite);
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if (size == 0)
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return NULL;
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return calls_srtp_generate_key_salt (size);
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}
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/**
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* calls_srtp_parse_sdp_crypto_attribute:
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* @attribute: attribute line
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* @error: a #GError
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*
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* Parse textual attribute line into structured data.
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*
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* Returns: (transfer full): A #calls_srtp_crypto_attribute containing
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* parsed attribute data, or %NULL if parsing failed.
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*/
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calls_srtp_crypto_attribute *
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calls_srtp_parse_sdp_crypto_attribute (const char *attribute,
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GError **error)
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{
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g_auto (GStrv) attr_fields = NULL;
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g_auto (GStrv) key_info_strv = NULL;
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guint n_attr_fields;
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guint n_key_params;
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char *tag_str;
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gint tag;
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calls_srtp_crypto_attribute *attr;
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calls_srtp_crypto_suite crypto_suite;
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gboolean need_mki;
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gboolean attr_invalid = FALSE;
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g_autofree char *err_msg = NULL;
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if (STR_IS_NULL_OR_EMPTY (attribute)) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Cannot parse null or empty strings");
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return NULL;
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}
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if (!g_str_has_prefix (attribute, "a=crypto:")) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Does not look like a SDP crypto attribute: %s",
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attribute);
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return NULL;
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}
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attr_fields = g_strsplit (attribute, " ", -1);
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n_attr_fields = g_strv_length (attr_fields);
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if (n_attr_fields < 3) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Need at least three fields in a SDP crypto attribute: %s",
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attribute);
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return NULL;
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}
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tag_str = &attr_fields[0][9]; /* 9 is the length of "a=crypto:" */
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/* leading zeros MUST NOT be used */
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if (*tag_str == '0') {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Tag must not have a leading zero: %s",
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tag_str);
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return NULL;
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}
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tag = (int) strtol (tag_str, NULL, 10);
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if (tag == 0) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Tag set to 0: %s", tag_str);
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return NULL;
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}
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if (tag < 0) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Tag must be positive: %s", tag_str);
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return NULL;
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}
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if (tag >= 1000000000) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Tag must have a maximum of 9 digits: %s", tag_str);
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return NULL;
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}
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if (g_strcmp0 (attr_fields[1], "AES_CM_128_HMAC_SHA1_32") == 0)
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crypto_suite = CALLS_SRTP_SUITE_AES_CM_128_SHA1_32;
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else if (g_strcmp0 (attr_fields[1], "AES_CM_128_HMAC_SHA1_80") == 0)
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crypto_suite = CALLS_SRTP_SUITE_AES_CM_128_SHA1_80;
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else if (g_strcmp0 (attr_fields[1], "AES_256_CM_HMAC_SHA1_32") == 0)
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crypto_suite = CALLS_SRTP_SUITE_AES_256_CM_SHA1_32;
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else if (g_strcmp0 (attr_fields[1], "AES_256_CM_HMAC_SHA1_80") == 0)
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crypto_suite = CALLS_SRTP_SUITE_AES_256_CM_SHA1_80;
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else
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crypto_suite = CALLS_SRTP_SUITE_UNKNOWN; /* error */
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/* key infos are split by ';' */
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key_info_strv = g_strsplit (attr_fields[2], ";", -1);
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n_key_params = g_strv_length (key_info_strv);
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/* libsrtp supports a maximum of 16 master keys */
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if (n_key_params > 16) {
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
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"More than 16 keys are not supported by libsrtp");
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return NULL;
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}
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need_mki = n_key_params > 1;
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|
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attr = calls_srtp_crypto_attribute_new (n_key_params);
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attr->tag = tag;
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attr->crypto_suite = crypto_suite;
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for (guint i = 0; i < n_key_params; i++) {
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char *key_info; /* srtp-key-info = key-salt ["|" lifetime] ["|" mki] */
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g_auto (GStrv) key_info_fields = NULL;
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guint n_key_infos;
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guint key_info_lifetime_index;
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guint key_info_mki_index;
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calls_srtp_crypto_key_param *key_param = &attr->key_params[i];
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if (!g_str_has_prefix (key_info_strv[i], "inline:")) {
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attr_invalid = TRUE;
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err_msg = g_strdup_printf ("Key method not 'inline': %s", key_info_strv[i]);
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break;
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}
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key_info = &key_info_strv[i][7]; /* 7 is the length of "inline:" */
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key_info_fields = g_strsplit (key_info, "|", -1);
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|
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n_key_infos = g_strv_length (key_info_fields);
|
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|
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switch (strlen (key_info_fields[0]) % 4) {
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case 3:
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key_param->b64_keysalt = g_strconcat (key_info_fields[0], "=", NULL);
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break;
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case 2:
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key_param->b64_keysalt = g_strconcat (key_info_fields[0], "==", NULL);
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break;
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case 1:
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g_assert_not_reached (); /* impossible with base64 */
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break;
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case 0:
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default:
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key_param->b64_keysalt = g_strdup (key_info_fields[0]);
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}
|
|
|
|
if (n_key_infos == 1) {
|
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key_info_lifetime_index = 0;
|
|
key_info_mki_index = 0;
|
|
} else if (n_key_infos == 2) {
|
|
/* either MKI or lifetime */
|
|
if (g_strstr_len (key_info_fields[1], -1, ":")) {
|
|
key_info_lifetime_index = 0;
|
|
key_info_mki_index = 1;
|
|
} else {
|
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key_info_lifetime_index = 1;
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key_info_mki_index = 0;
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}
|
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} else if (n_key_infos == 3) {
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key_info_lifetime_index = 1;
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key_info_mki_index = 2;
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} else {
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/* invalid */
|
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attr_invalid = TRUE;
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err_msg = g_strdup_printf ("Unexpected number of key-info fields: %s", key_info);
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break;
|
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}
|
|
|
|
/* lifetime type */
|
|
if (key_info_lifetime_index) {
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|
char *lifetime_number;
|
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char *endptr;
|
|
if (g_str_has_prefix (key_info_fields[key_info_lifetime_index], "2^")) {
|
|
key_param->lifetime_type = CALLS_SRTP_LIFETIME_AS_POWER_OF_TWO;
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lifetime_number = &key_info_fields[key_info_lifetime_index][2]; /* 2 is the length of "2^" */
|
|
} else {
|
|
key_param->lifetime_type = CALLS_SRTP_LIFETIME_AS_DECIMAL_NUMBER;
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|
lifetime_number = key_info_fields[key_info_lifetime_index];
|
|
}
|
|
|
|
if (*lifetime_number == '0') {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("Leading zero in lifetime: %s",
|
|
key_info_fields[key_info_lifetime_index]);
|
|
break;
|
|
}
|
|
|
|
key_param->lifetime = g_ascii_strtoull (lifetime_number, &endptr, 10);
|
|
if (key_param->lifetime == 0) {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("Lifetime set to zero: %s",
|
|
key_info_fields[key_info_lifetime_index]);
|
|
break;
|
|
}
|
|
|
|
if (*endptr != '\0') {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("Non numeric characters in lifetime: %s",
|
|
key_info_fields[key_info_lifetime_index]);
|
|
break;
|
|
}
|
|
|
|
/* out of bounds check will be performed during validation of the attribute */
|
|
}
|
|
|
|
if (need_mki && key_info_mki_index == 0) {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("MKI needed, but not found: %s", key_info);
|
|
break;
|
|
}
|
|
|
|
if (need_mki) {
|
|
g_auto (GStrv) mki_split = g_strsplit (key_info_fields[key_info_mki_index], ":", -1);
|
|
guint n_mki = g_strv_length (mki_split);
|
|
guint64 mki;
|
|
guint64 mki_length;
|
|
char *endptr;
|
|
|
|
if (n_mki != 2) {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("MKI field not separated into two fields by colon: %s",
|
|
key_info_fields[key_info_mki_index]);
|
|
break;
|
|
}
|
|
|
|
/* no leading zero allowed */
|
|
if (*mki_split[0] == '0') {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("Leading zero in MKI: %s", mki_split[0]);
|
|
break;
|
|
}
|
|
|
|
if (*mki_split[1] == '0') {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("Leading zero in MKI length: %s", mki_split[1]);
|
|
break;
|
|
}
|
|
|
|
mki = g_ascii_strtoull (mki_split[0], &endptr, 10);
|
|
if (mki == 0) {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("MKI set to 0: %s", mki_split[0]);
|
|
break;
|
|
}
|
|
|
|
if (*endptr != '\0') {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("Non numeric characters found in MKI: %s", mki_split[0]);
|
|
break;
|
|
}
|
|
|
|
mki_length = g_ascii_strtoull (mki_split[1], &endptr, 10);
|
|
/* number of bytes of the MKI field in the SRTP packet */
|
|
if (mki_length == 0 || mki_length > 128) {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("MKI length not between 0 and 128: %s", mki_split[1]);
|
|
break;
|
|
}
|
|
|
|
if (*endptr != '\0') {
|
|
attr_invalid = TRUE;
|
|
err_msg = g_strdup_printf ("Non numeric characters found in MKI length: %s", mki_split[1]);
|
|
break;
|
|
}
|
|
|
|
key_param->mki = mki;
|
|
key_param->mki_length = (guint) mki_length;
|
|
}
|
|
|
|
}
|
|
|
|
if (attr_invalid) {
|
|
calls_srtp_crypto_attribute_free (attr);
|
|
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED, err_msg);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* TODO session parameters */
|
|
|
|
if (!validate_crypto_attribute (attr, error)) {
|
|
calls_srtp_crypto_attribute_free (attr);
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
return attr;
|
|
}
|
|
|
|
/**
|
|
* calls_srtp_print_sdp_crypto_attribute:
|
|
* @attr: Structured crypto attribute
|
|
* @error: A #GError
|
|
*
|
|
* Returns: (transfer full): Textual representation of crypto attribute
|
|
* or %NULL if attribute contains invalid data.
|
|
*/
|
|
char *
|
|
calls_srtp_print_sdp_crypto_attribute (calls_srtp_crypto_attribute *attr,
|
|
GError **error)
|
|
{
|
|
const char *crypto_suite;
|
|
GString *attr_str;
|
|
|
|
if (!validate_crypto_attribute (attr, error))
|
|
return NULL;
|
|
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_CM_128_SHA1_32)
|
|
crypto_suite = "AES_CM_128_HMAC_SHA1_32";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_CM_128_SHA1_80)
|
|
crypto_suite = "AES_CM_128_HMAC_SHA1_80";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_192_CM_SHA1_32)
|
|
crypto_suite = "AES_196_CM_HMAC_SHA1_32";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_192_CM_SHA1_80)
|
|
crypto_suite = "AES_196_CM_HMAC_SHA1_80";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_256_CM_SHA1_32)
|
|
crypto_suite = "AES_256_CM_HMAC_SHA1_32";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_256_CM_SHA1_80)
|
|
crypto_suite = "AES_256_CM_HMAC_SHA1_80";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_F8_128_HMAC_SHA1_32)
|
|
crypto_suite = "F8_128_HMAC_SHA1_80";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_AEAD_AES_128_GCM)
|
|
crypto_suite = "AEAD_AES_128_GCM";
|
|
else if (attr->crypto_suite == CALLS_SRTP_SUITE_AEAD_AES_256_GCM)
|
|
crypto_suite = "AEAD_AES_256_GCM";
|
|
else
|
|
return NULL;
|
|
|
|
attr_str = g_string_sized_new (96); /* minimal string length is 82 */
|
|
|
|
g_string_append_printf (attr_str, "a=crypto:%d %s ",
|
|
attr->tag, crypto_suite);
|
|
|
|
/* key parameters */
|
|
for (guint i = 0; i < attr->n_key_params; i++) {
|
|
calls_srtp_crypto_key_param *key_param = &attr->key_params[i];
|
|
int keylen = strlen (key_param->b64_keysalt);
|
|
|
|
/* https://www.rfc-editor.org/rfc/rfc4568.html#section-6.1 says:
|
|
When base64 decoding the key and salt, padding characters (i.e.,
|
|
one or two "=" at the end of the base64-encoded data) are discarded
|
|
(see [RFC3548] for details).
|
|
*/
|
|
if (key_param->b64_keysalt[keylen - 2] == '=')
|
|
g_string_append_printf (attr_str, "inline:%.*s", keylen - 2, key_param->b64_keysalt);
|
|
else if (key_param->b64_keysalt[keylen - 1] == '=')
|
|
g_string_append_printf (attr_str, "inline:%.*s", keylen - 1, key_param->b64_keysalt);
|
|
else
|
|
g_string_append_printf (attr_str, "inline:%s", key_param->b64_keysalt);
|
|
if (key_param->lifetime_type == CALLS_SRTP_LIFETIME_AS_DECIMAL_NUMBER)
|
|
g_string_append_printf (attr_str, "|%" G_GINT64_FORMAT, key_param->lifetime);
|
|
if (key_param->lifetime_type == CALLS_SRTP_LIFETIME_AS_POWER_OF_TWO)
|
|
g_string_append_printf (attr_str, "|2^%" G_GINT64_FORMAT, key_param->lifetime);
|
|
|
|
if (key_param->mki > 0) {
|
|
g_string_append_printf(attr_str, "|%" G_GUINT64_FORMAT ":%u",
|
|
key_param->mki, key_param->mki_length);
|
|
}
|
|
|
|
if (i + 1 < attr->n_key_params)
|
|
g_string_append (attr_str, ";");
|
|
}
|
|
|
|
/* TODO session parameters */
|
|
|
|
return g_string_free (attr_str, FALSE);
|
|
}
|
|
|
|
/**
|
|
* calls_srtp_crypto_attribute_new:
|
|
* @n_key_params: The number of key parameters
|
|
*
|
|
* Returns: (transfer full): A new empty #calls_srtp_crypto_attribute
|
|
* with @n_key_params key parameters allocated. Key parameters must be set either
|
|
* manually or by using calls_srtp_crypto_attribute_init_keys().
|
|
*
|
|
* Free the attribute with calls_srtp_crypto_attribute_free() after you are done.
|
|
*/
|
|
calls_srtp_crypto_attribute *
|
|
calls_srtp_crypto_attribute_new (guint n_key_params)
|
|
{
|
|
calls_srtp_crypto_attribute *attr;
|
|
|
|
g_return_val_if_fail (n_key_params > 0 || n_key_params < 16, NULL);
|
|
|
|
attr = g_new0 (calls_srtp_crypto_attribute, 1);
|
|
attr->key_params = g_new0 (calls_srtp_crypto_key_param, n_key_params);
|
|
attr->n_key_params = n_key_params;
|
|
|
|
return attr;
|
|
}
|
|
|
|
/**
|
|
* calls_srtp_crypto_attribute_init_keys:
|
|
* @attr: A #calls_srtp_crypto_attribute
|
|
*
|
|
* Generate key material and set sane default parameters for each
|
|
* key parameter.
|
|
*/
|
|
gboolean
|
|
calls_srtp_crypto_attribute_init_keys (calls_srtp_crypto_attribute *attr)
|
|
{
|
|
gsize key_size;
|
|
gboolean need_mki;
|
|
|
|
g_return_val_if_fail (attr, FALSE);
|
|
|
|
key_size = get_key_size_for_suite (attr->crypto_suite);
|
|
if (key_size == 0)
|
|
return FALSE;
|
|
|
|
need_mki = attr->n_key_params > 1;
|
|
|
|
for (uint i = 0; i < attr->n_key_params; i++) {
|
|
g_autofree guchar *key = calls_srtp_generate_key_salt (key_size);
|
|
g_free (attr->key_params[i].b64_keysalt);
|
|
attr->key_params[i].b64_keysalt = g_base64_encode (key, key_size);
|
|
|
|
if (need_mki) {
|
|
attr->key_params[i].mki = i + 1;
|
|
attr->key_params[i].mki_length = 4;
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
/**
|
|
* calls_srtp_crypto_attribute_free:
|
|
* @attr: A #calls_srtp_crypto_attribute
|
|
*
|
|
* Frees all memory allocated for @attr.
|
|
*/
|
|
void
|
|
calls_srtp_crypto_attribute_free (calls_srtp_crypto_attribute *attr)
|
|
{
|
|
for (guint i = 0; i < attr->n_key_params; i++) {
|
|
g_free (attr->key_params[i].b64_keysalt);
|
|
}
|
|
|
|
g_free (attr->key_params);
|
|
g_free (attr->b64_fec_key);
|
|
g_free (attr);
|
|
}
|
|
|
|
/**
|
|
* calls_srtp_crypto_get_srtpdec_params:
|
|
* @attr: A #calls_srtp_crypto_attribute
|
|
* @srtp_cipher (out): SRTP cipher
|
|
* @srtp_auth (out): SRTP auth
|
|
* @srtcp_cipher (out): SRTCP cipher
|
|
* @srtcp_auth (out): SRTCP auth
|
|
*
|
|
* Sets the parameters suitable for #GstSrtpDec (as a #GstCaps).
|
|
*/
|
|
gboolean
|
|
calls_srtp_crypto_get_srtpdec_params (calls_srtp_crypto_attribute *attr,
|
|
const char **srtp_cipher,
|
|
const char **srtp_auth,
|
|
const char **srtcp_cipher,
|
|
const char **srtcp_auth)
|
|
{
|
|
g_return_val_if_fail (attr, FALSE);
|
|
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_CM_128_SHA1_32) {
|
|
*srtp_cipher = attr->unencrypted_srtp ? "null" : "aes-128-icm";
|
|
*srtp_auth = attr->unauthenticated_srtp ? "null" : "hmac-sha1-32";
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? "null" : "aes-128-icm";
|
|
*srtcp_auth = attr->unencrypted_srtcp ? "null" : "hmac-sha1-32";
|
|
|
|
return TRUE;
|
|
} else if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_CM_128_SHA1_80) {
|
|
*srtp_cipher = attr->unencrypted_srtp ? "null" : "aes-128-icm";
|
|
*srtp_auth = attr->unauthenticated_srtp ? "null" : "hmac-sha1-80";
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? "null" : "aes-128-icm";
|
|
*srtcp_auth = attr->unencrypted_srtcp ? "null" : "hmac-sha1-80";
|
|
|
|
return TRUE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_192_CM_SHA1_32) {
|
|
/* NOT OFFERED BY GSTREAMER
|
|
*srtp_cipher = attr->unencrypted_srtp ? "null" : "aes-192-icm";
|
|
*srtp_auth = attr->unauthenticated_srtp ? "null" : "hmac-sha1-32";
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? "null" : "aes-192-icm";
|
|
*srtcp_auth = attr->unencrypted_srtcp ? "null" : "hmac-sha1-32";
|
|
*/
|
|
return FALSE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_192_CM_SHA1_80) {
|
|
/* NOT OFFERED BY GSTREAMER
|
|
*srtp_cipher = attr->unencrypted_srtp ? "null" : "aes-192-icm";
|
|
*srtp_auth = attr->unauthenticated_srtp ? "null" : "hmac-sha1-80";
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? "null" : "aes-192-icm";
|
|
*srtcp_auth = attr->unencrypted_srtcp ? "null" : "hmac-sha1-80";
|
|
*/
|
|
return FALSE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_256_CM_SHA1_32) {
|
|
*srtp_cipher = attr->unencrypted_srtp ? "null" : "aes-256-icm";
|
|
*srtp_auth = attr->unauthenticated_srtp ? "null" : "hmac-sha1-32";
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? "null" : "aes-256-icm";
|
|
*srtcp_auth = attr->unencrypted_srtcp ? "null" : "hmac-sha1-32";
|
|
|
|
return TRUE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_256_CM_SHA1_80) {
|
|
*srtp_cipher = attr->unencrypted_srtp ? "null" : "aes-256-icm";
|
|
*srtp_auth = attr->unauthenticated_srtp ? "null" : "hmac-sha1-80";
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? "null" : "aes-256-icm";
|
|
*srtcp_auth = attr->unencrypted_srtcp ? "null" : "hmac-sha1-80";
|
|
|
|
return TRUE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_F8_128_HMAC_SHA1_32) {
|
|
// F8 IS NOT OFFERED BY GSTREAMER
|
|
return FALSE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AEAD_AES_128_GCM) {
|
|
|
|
return FALSE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AEAD_AES_256_GCM) {
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
|
|
/**
|
|
* calls_srtp_crypto_get_srtpenc_params:
|
|
* @attr: A #calls_srtp_crypto_attribute
|
|
* @srtp_cipher (out): SRTP cipher
|
|
* @srtp_auth (out): SRTP auth
|
|
* @srtcp_cipher (out): SRTCP cipher
|
|
* @srtcp_auth (out): SRTCP auth
|
|
*
|
|
* Sets the parameters suitable for #GstSrtpDec (as a #GstCaps).
|
|
*/
|
|
gboolean
|
|
calls_srtp_crypto_get_srtpenc_params (calls_srtp_crypto_attribute *attr,
|
|
GstSrtpCipherType *srtp_cipher,
|
|
GstSrtpAuthType *srtp_auth,
|
|
GstSrtpCipherType *srtcp_cipher,
|
|
GstSrtpAuthType *srtcp_auth)
|
|
{
|
|
g_return_val_if_fail (attr, FALSE);
|
|
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_CM_128_SHA1_32) {
|
|
*srtp_cipher = attr->unencrypted_srtp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_128_ICM;
|
|
*srtp_auth = attr->unauthenticated_srtp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_32;
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_128_ICM;
|
|
*srtcp_auth = attr->unencrypted_srtcp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_32;
|
|
|
|
return TRUE;
|
|
} else if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_CM_128_SHA1_80) {
|
|
|
|
*srtp_cipher = attr->unencrypted_srtp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_128_ICM;
|
|
*srtp_auth = attr->unauthenticated_srtp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_80;
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_128_ICM;
|
|
*srtcp_auth = attr->unencrypted_srtcp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_80;
|
|
|
|
return TRUE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_256_CM_SHA1_32) {
|
|
*srtp_cipher = attr->unencrypted_srtp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_256_ICM;
|
|
*srtp_auth = attr->unauthenticated_srtp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_32;
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_256_ICM;
|
|
*srtcp_auth = attr->unencrypted_srtcp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_32;
|
|
|
|
return TRUE;
|
|
}
|
|
if (attr->crypto_suite == CALLS_SRTP_SUITE_AES_256_CM_SHA1_80) {
|
|
*srtp_cipher = attr->unencrypted_srtp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_256_ICM;
|
|
*srtp_auth = attr->unauthenticated_srtp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_80;
|
|
*srtcp_cipher = attr->unencrypted_srtcp ? GST_SRTP_CIPHER_NULL : GST_SRTP_CIPHER_AES_256_ICM;
|
|
*srtcp_auth = attr->unencrypted_srtcp ? GST_SRTP_AUTH_NULL : GST_SRTP_AUTH_HMAC_SHA1_80;
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
return FALSE;
|
|
}
|