| Index: srtp/test/rtp_decoder.c
|
| diff --git a/srtp/test/rtp_decoder.c b/srtp/test/rtp_decoder.c
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..57e2d331d36907d5068d5ee8be5fb625611595de
|
| --- /dev/null
|
| +++ b/srtp/test/rtp_decoder.c
|
| @@ -0,0 +1,515 @@
|
| +/*
|
| + * rtp_decoder.c
|
| + *
|
| + * decoder structures and functions for SRTP pcap decoder
|
| + *
|
| + * Example:
|
| + * $ wget --no-check-certificate https://raw.githubusercontent.com/gteissier/srtp-decrypt/master/marseillaise-srtp.pcap
|
| + * $ ./test/rtp_decoder -a -t 0 -e 128 -b aSBrbm93IGFsbCB5b3VyIGxpdHRsZSBzZWNyZXRz \
|
| + * < ~/marseillaise-srtp.pcap | text2pcap -t "%M:%S." -u 10000,10000 - - > ./marseillaise-rtp.pcap
|
| + *
|
| + * Bernardo Torres <bernardo@torresautomacao.com.br>
|
| + *
|
| + * Some structure and code from https://github.com/gteissier/srtp-decrypt
|
| + */
|
| +/*
|
| + *
|
| + * Copyright (c) 2001-2006 Cisco Systems, Inc.
|
| + * All rights reserved.
|
| + *
|
| + * Redistribution and use in source and binary forms, with or without
|
| + * modification, are permitted provided that the following conditions
|
| + * are met:
|
| + *
|
| + * Redistributions of source code must retain the above copyright
|
| + * notice, this list of conditions and the following disclaimer.
|
| + *
|
| + * Redistributions in binary form must reproduce the above
|
| + * copyright notice, this list of conditions and the following
|
| + * disclaimer in the documentation and/or other materials provided
|
| + * with the distribution.
|
| + *
|
| + * Neither the name of the Cisco Systems, Inc. nor the names of its
|
| + * contributors may be used to endorse or promote products derived
|
| + * from this software without specific prior written permission.
|
| + *
|
| + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
| + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
| + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
| + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
| + * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
|
| + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
| + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
| + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
| + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
| + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
| + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
|
| + * OF THE POSSIBILITY OF SUCH DAMAGE.
|
| + *
|
| + */
|
| +#include "getopt_s.h" /* for local getopt() */
|
| +#include <assert.h> /* for assert() */
|
| +
|
| +#include <pcap.h>
|
| +#include "rtp_decoder.h"
|
| +
|
| +#define MAX_KEY_LEN 96
|
| +#define MAX_FILTER 256
|
| +
|
| +int
|
| +main (int argc, char *argv[]) {
|
| + char errbuf[PCAP_ERRBUF_SIZE];
|
| + bpf_u_int32 pcap_net = 0;
|
| + pcap_t *pcap_handle;
|
| +#if BEW
|
| + struct sockaddr_in local;
|
| +#endif
|
| + sec_serv_t sec_servs = sec_serv_none;
|
| + int c;
|
| + int key_size = 128;
|
| + int tag_size = 8;
|
| + int gcm_on = 0;
|
| + char *input_key = NULL;
|
| + int b64_input = 0;
|
| + char key[MAX_KEY_LEN];
|
| + struct bpf_program fp;
|
| + char filter_exp[MAX_FILTER] = "";
|
| + rtp_decoder_t dec;
|
| + srtp_policy_t policy;
|
| + err_status_t status;
|
| + int len;
|
| + int expected_len;
|
| + int do_list_mods = 0;
|
| +
|
| + fprintf(stderr, "Using %s [0x%x]\n", srtp_get_version_string(), srtp_get_version());
|
| +
|
| + /* initialize srtp library */
|
| + status = srtp_init();
|
| + if (status) {
|
| + fprintf(stderr, "error: srtp initialization failed with error code %d\n", status);
|
| + exit(1);
|
| + }
|
| +
|
| + /* check args */
|
| + while (1) {
|
| + c = getopt_s(argc, argv, "b:k:gt:ae:ld:f:");
|
| + if (c == -1) {
|
| + break;
|
| + }
|
| + switch (c) {
|
| + case 'b':
|
| + b64_input = 1;
|
| + /* fall thru */
|
| + case 'k':
|
| + input_key = optarg_s;
|
| + break;
|
| + case 'e':
|
| + key_size = atoi(optarg_s);
|
| + if (key_size != 128 && key_size != 256) {
|
| + fprintf(stderr, "error: encryption key size must be 128 or 256 (%d)\n", key_size);
|
| + exit(1);
|
| + }
|
| + input_key = malloc(key_size);
|
| + sec_servs |= sec_serv_conf;
|
| + break;
|
| + case 't':
|
| + tag_size = atoi(optarg_s);
|
| + if (tag_size != 8 && tag_size != 16) {
|
| + fprintf(stderr, "error: GCM tag size must be 8 or 16 (%d)\n", tag_size);
|
| + //exit(1);
|
| + }
|
| + break;
|
| + case 'a':
|
| + sec_servs |= sec_serv_auth;
|
| + break;
|
| + case 'g':
|
| + gcm_on = 1;
|
| + sec_servs |= sec_serv_auth;
|
| + break;
|
| + case 'd':
|
| + status = crypto_kernel_set_debug_module(optarg_s, 1);
|
| + if (status) {
|
| + fprintf(stderr, "error: set debug module (%s) failed\n", optarg_s);
|
| + exit(1);
|
| + }
|
| + break;
|
| + case 'f':
|
| + if(strlen(optarg_s) > MAX_FILTER){
|
| + fprintf(stderr, "error: filter bigger than %d characters\n", MAX_FILTER);
|
| + exit(1);
|
| + }
|
| + fprintf(stderr, "Setting filter as %s\n", optarg_s);
|
| + strcpy(filter_exp, optarg_s);
|
| + break;
|
| + case 'l':
|
| + do_list_mods = 1;
|
| + break;
|
| + default:
|
| + usage(argv[0]);
|
| + }
|
| + }
|
| +
|
| + if (do_list_mods) {
|
| + status = crypto_kernel_list_debug_modules();
|
| + if (status) {
|
| + fprintf(stderr, "error: list of debug modules failed\n");
|
| + exit(1);
|
| + }
|
| + return 0;
|
| + }
|
| +
|
| + if ((sec_servs && !input_key) || (!sec_servs && input_key)) {
|
| + /*
|
| + * a key must be provided if and only if security services have
|
| + * been requested
|
| + */
|
| + if(input_key == NULL){
|
| + fprintf(stderr, "key not provided\n");
|
| + }
|
| + if(!sec_servs){
|
| + fprintf(stderr, "no secservs\n");
|
| + }
|
| + fprintf(stderr, "provided\n");
|
| + usage(argv[0]);
|
| + }
|
| +
|
| +
|
| +
|
| + /* report security services selected on the command line */
|
| + fprintf(stderr, "security services: ");
|
| + if (sec_servs & sec_serv_conf)
|
| + fprintf(stderr, "confidentiality ");
|
| + if (sec_servs & sec_serv_auth)
|
| + fprintf(stderr, "message authentication");
|
| + if (sec_servs == sec_serv_none)
|
| + fprintf(stderr, "none");
|
| + fprintf(stderr, "\n");
|
| +
|
| + /* set up the srtp policy and master key */
|
| + if (sec_servs) {
|
| + /*
|
| + * create policy structure, using the default mechanisms but
|
| + * with only the security services requested on the command line,
|
| + * using the right SSRC value
|
| + */
|
| + switch (sec_servs) {
|
| + case sec_serv_conf_and_auth:
|
| + if (gcm_on) {
|
| +#ifdef OPENSSL
|
| + switch (key_size) {
|
| + case 128:
|
| + crypto_policy_set_aes_gcm_128_8_auth(&policy.rtp);
|
| + crypto_policy_set_aes_gcm_128_8_auth(&policy.rtcp);
|
| + break;
|
| + case 256:
|
| + crypto_policy_set_aes_gcm_256_8_auth(&policy.rtp);
|
| + crypto_policy_set_aes_gcm_256_8_auth(&policy.rtcp);
|
| + break;
|
| + }
|
| +#else
|
| + fprintf(stderr, "error: GCM mode only supported when using the OpenSSL crypto engine.\n");
|
| + return 0;
|
| +#endif
|
| + } else {
|
| + switch (key_size) {
|
| + case 128:
|
| + crypto_policy_set_rtp_default(&policy.rtp);
|
| + crypto_policy_set_rtcp_default(&policy.rtcp);
|
| + break;
|
| + case 256:
|
| + crypto_policy_set_aes_cm_256_hmac_sha1_80(&policy.rtp);
|
| + crypto_policy_set_rtcp_default(&policy.rtcp);
|
| + break;
|
| + }
|
| + }
|
| + break;
|
| + case sec_serv_conf:
|
| + if (gcm_on) {
|
| + fprintf(stderr, "error: GCM mode must always be used with auth enabled\n");
|
| + return -1;
|
| + } else {
|
| + switch (key_size) {
|
| + case 128:
|
| + crypto_policy_set_aes_cm_128_null_auth(&policy.rtp);
|
| + crypto_policy_set_rtcp_default(&policy.rtcp);
|
| + break;
|
| + case 256:
|
| + crypto_policy_set_aes_cm_256_null_auth(&policy.rtp);
|
| + crypto_policy_set_rtcp_default(&policy.rtcp);
|
| + break;
|
| + }
|
| + }
|
| + break;
|
| + case sec_serv_auth:
|
| + if (gcm_on) {
|
| +#ifdef OPENSSL
|
| + switch (key_size) {
|
| + case 128:
|
| + crypto_policy_set_aes_gcm_128_8_only_auth(&policy.rtp);
|
| + crypto_policy_set_aes_gcm_128_8_only_auth(&policy.rtcp);
|
| + break;
|
| + case 256:
|
| + crypto_policy_set_aes_gcm_256_8_only_auth(&policy.rtp);
|
| + crypto_policy_set_aes_gcm_256_8_only_auth(&policy.rtcp);
|
| + break;
|
| + }
|
| +#else
|
| + printf("error: GCM mode only supported when using the OpenSSL crypto engine.\n");
|
| + return 0;
|
| +#endif
|
| + } else {
|
| + crypto_policy_set_null_cipher_hmac_sha1_80(&policy.rtp);
|
| + crypto_policy_set_rtcp_default(&policy.rtcp);
|
| + }
|
| + break;
|
| + default:
|
| + fprintf(stderr, "error: unknown security service requested\n");
|
| + return -1;
|
| + }
|
| +
|
| + policy.key = (uint8_t *) key;
|
| + policy.ekt = NULL;
|
| + policy.next = NULL;
|
| + policy.window_size = 128;
|
| + policy.allow_repeat_tx = 0;
|
| + policy.rtp.sec_serv = sec_servs;
|
| + policy.rtcp.sec_serv = sec_servs; //sec_serv_none; /* we don't do RTCP anyway */
|
| + fprintf(stderr, "setting tag len %d\n", tag_size);
|
| +policy.rtp.auth_tag_len = tag_size;
|
| +
|
| + if (gcm_on && tag_size != 8) {
|
| + fprintf(stderr, "setted tag len %d\n", tag_size);
|
| + policy.rtp.auth_tag_len = tag_size;
|
| + }
|
| +
|
| + /*
|
| + * read key from hexadecimal or base64 on command line into an octet string
|
| + */
|
| + if (b64_input) {
|
| + int pad;
|
| + expected_len = policy.rtp.cipher_key_len*4/3;
|
| + len = base64_string_to_octet_string(key, &pad, input_key, expected_len);
|
| + if (pad != 0) {
|
| + fprintf(stderr, "error: padding in base64 unexpected\n");
|
| + exit(1);
|
| + }
|
| + } else {
|
| + expected_len = policy.rtp.cipher_key_len*2;
|
| + len = hex_string_to_octet_string(key, input_key, expected_len);
|
| + }
|
| + /* check that hex string is the right length */
|
| + if (len < expected_len) {
|
| + fprintf(stderr,
|
| + "error: too few digits in key/salt "
|
| + "(should be %d digits, found %d)\n",
|
| + expected_len, len);
|
| + exit(1);
|
| + }
|
| + if (strlen(input_key) > policy.rtp.cipher_key_len*2) {
|
| + fprintf(stderr,
|
| + "error: too many digits in key/salt "
|
| + "(should be %d hexadecimal digits, found %u)\n",
|
| + policy.rtp.cipher_key_len*2, (unsigned)strlen(input_key));
|
| + exit(1);
|
| + }
|
| +
|
| + fprintf(stderr, "set master key/salt to %s/", octet_string_hex_string(key, 16));
|
| + fprintf(stderr, "%s\n", octet_string_hex_string(key+16, 14));
|
| +
|
| + } else {
|
| + /*
|
| + * we're not providing security services, so set the policy to the
|
| + * null policy
|
| + *
|
| + * Note that this policy does not conform to the SRTP
|
| + * specification, since RTCP authentication is required. However,
|
| + * the effect of this policy is to turn off SRTP, so that this
|
| + * application is now a vanilla-flavored RTP application.
|
| + */
|
| + policy.key = (uint8_t *)key;
|
| + policy.ssrc.type = ssrc_specific;
|
| + policy.rtp.cipher_type = NULL_CIPHER;
|
| + policy.rtp.cipher_key_len = 0;
|
| + policy.rtp.auth_type = NULL_AUTH;
|
| + policy.rtp.auth_key_len = 0;
|
| + policy.rtp.auth_tag_len = 0;
|
| + policy.rtp.sec_serv = sec_serv_none;
|
| + policy.rtcp.cipher_type = NULL_CIPHER;
|
| + policy.rtcp.cipher_key_len = 0;
|
| + policy.rtcp.auth_type = NULL_AUTH;
|
| + policy.rtcp.auth_key_len = 0;
|
| + policy.rtcp.auth_tag_len = 0;
|
| + policy.rtcp.sec_serv = sec_serv_none;
|
| + policy.window_size = 0;
|
| + policy.allow_repeat_tx = 0;
|
| + policy.ekt = NULL;
|
| + policy.next = NULL;
|
| + }
|
| +
|
| + pcap_handle = pcap_open_offline("-", errbuf);
|
| +
|
| + if (!pcap_handle) {
|
| + fprintf(stderr, "libpcap failed to open file '%s'\n", errbuf);
|
| + exit(1);
|
| + }
|
| + assert(pcap_handle != NULL);
|
| + if ((pcap_compile(pcap_handle, &fp, filter_exp, 1, pcap_net)) == -1){
|
| + fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp,
|
| + pcap_geterr(pcap_handle));
|
| + return (2);
|
| + }
|
| + if (pcap_setfilter(pcap_handle, &fp) == -1){
|
| + fprintf(stderr, "couldn't install filter %s: %s\n", filter_exp,
|
| + pcap_geterr(pcap_handle));
|
| + return (2);
|
| + }
|
| + dec = rtp_decoder_alloc();
|
| + if (dec == NULL) {
|
| + fprintf(stderr, "error: malloc() failed\n");
|
| + exit(1);
|
| + }
|
| + fprintf(stderr, "Starting decoder\n");
|
| + rtp_decoder_init(dec, policy);
|
| +
|
| + pcap_loop(pcap_handle, 0, rtp_decoder_handle_pkt, (u_char *)dec);
|
| +
|
| + rtp_decoder_deinit_srtp(dec);
|
| + rtp_decoder_dealloc(dec);
|
| +
|
| + status = srtp_shutdown();
|
| + if (status) {
|
| + fprintf(stderr, "error: srtp shutdown failed with error code %d\n", status);
|
| + exit(1);
|
| + }
|
| +
|
| + return 0;
|
| +}
|
| +
|
| +
|
| +void
|
| +usage(char *string) {
|
| +
|
| + fprintf(stderr, "usage: %s [-d <debug>]* [[-k][-b] <key> [-a][-e]]\n"
|
| + "or %s -l\n"
|
| + "where -a use message authentication\n"
|
| + " -e <key size> use encryption (use 128 or 256 for key size)\n"
|
| + " -g Use AES-GCM mode (must be used with -e)\n"
|
| + " -t <tag size> Tag size to use in GCM mode (use 8 or 16)\n"
|
| + " -k <key> sets the srtp master key given in hexadecimal\n"
|
| + " -b <key> sets the srtp master key given in base64\n"
|
| + " -l list debug modules\n"
|
| + " -f \"<pcap filter>\" to filter only the desired SRTP packets\n"
|
| + " -d <debug> turn on debugging for module <debug>\n",
|
| + string, string);
|
| + exit(1);
|
| +
|
| +}
|
| +
|
| +rtp_decoder_t
|
| +rtp_decoder_alloc(void) {
|
| + return (rtp_decoder_t)malloc(sizeof(rtp_decoder_ctx_t));
|
| +}
|
| +
|
| +void
|
| +rtp_decoder_dealloc(rtp_decoder_t rtp_ctx) {
|
| + free(rtp_ctx);
|
| +}
|
| +
|
| +err_status_t
|
| +rtp_decoder_init_srtp(rtp_decoder_t decoder, unsigned int ssrc) {
|
| + decoder->policy.ssrc.value = htonl(ssrc);
|
| + return srtp_create(&decoder->srtp_ctx, &decoder->policy);
|
| +}
|
| +
|
| +int
|
| +rtp_decoder_deinit_srtp(rtp_decoder_t decoder) {
|
| + return srtp_dealloc(decoder->srtp_ctx);
|
| +}
|
| +
|
| +int
|
| +rtp_decoder_init(rtp_decoder_t dcdr, srtp_policy_t policy){
|
| + dcdr->rtp_offset = DEFAULT_RTP_OFFSET;
|
| + dcdr->srtp_ctx = NULL;
|
| + dcdr->start_tv.tv_usec = 0;
|
| + dcdr->start_tv.tv_sec = 0;
|
| + dcdr->frame_nr = -1;
|
| + dcdr->policy = policy;
|
| + dcdr->policy.ssrc.type = ssrc_specific;
|
| + return 0;
|
| +}
|
| +
|
| +/*
|
| + * decodes key as base64
|
| + */
|
| +
|
| +void hexdump(const void *ptr, size_t size) {
|
| + int i, j;
|
| + const unsigned char *cptr = ptr;
|
| +
|
| + for (i = 0; i < size; i += 16) {
|
| + fprintf(stdout, "%04x ", i);
|
| + for (j = 0; j < 16 && i+j < size; j++) {
|
| + fprintf(stdout, "%02x ", cptr[i+j]);
|
| + }
|
| + fprintf(stdout, "\n");
|
| + }
|
| +}
|
| +
|
| +void
|
| +rtp_decoder_handle_pkt(u_char *arg, const struct pcap_pkthdr *hdr,
|
| + const u_char *bytes){
|
| + rtp_decoder_t dcdr = (rtp_decoder_t)arg;
|
| + int pktsize;
|
| + struct timeval delta;
|
| + int octets_recvd;
|
| + err_status_t status;
|
| + dcdr->frame_nr++;
|
| +
|
| + if (dcdr->start_tv.tv_sec == 0 && dcdr->start_tv.tv_sec == 0) {
|
| + dcdr->start_tv = hdr->ts;
|
| + }
|
| +
|
| + if (hdr->caplen < dcdr->rtp_offset) {
|
| + return;
|
| + }
|
| + const void *rtp_packet = bytes + dcdr->rtp_offset;
|
| +
|
| + memcpy((void *)&dcdr->message, rtp_packet, hdr->caplen - dcdr->rtp_offset);
|
| + pktsize = hdr->caplen - dcdr->rtp_offset;
|
| + octets_recvd = pktsize;
|
| +
|
| + if (octets_recvd == -1) {
|
| + return;
|
| + }
|
| +
|
| + /* verify rtp header */
|
| + if (dcdr->message.header.version != 2) {
|
| + return; //return -1;
|
| + }
|
| + if(dcdr->srtp_ctx == NULL){
|
| + status = rtp_decoder_init_srtp(dcdr, dcdr->message.header.ssrc);
|
| + if (status) {
|
| + exit(1);
|
| + }
|
| + }
|
| + if(dcdr->srtp_ctx != NULL){
|
| + }
|
| + status = srtp_unprotect(dcdr->srtp_ctx, &dcdr->message, &octets_recvd);
|
| + if (status){
|
| + return;
|
| + }
|
| + timersub(&hdr->ts, &dcdr->start_tv, &delta);
|
| + fprintf(stdout, "%02ld:%02ld.%06lu\n", delta.tv_sec/60, delta.tv_sec%60, delta.tv_usec);
|
| + hexdump(&dcdr->message, pktsize);
|
| +}
|
| +
|
| +void rtp_print_error(err_status_t status, char *message){
|
| + fprintf(stderr,
|
| + "error: %s %d%s\n", message, status,
|
| + status == err_status_replay_fail ? " (replay check failed)" :
|
| + status == err_status_bad_param ? " (bad param)" :
|
| + status == err_status_no_ctx ? " (no context)" :
|
| + status == err_status_cipher_fail ? " (cipher failed)" :
|
| + status == err_status_key_expired ? " (key expired)" :
|
| + status == err_status_auth_fail ? " (auth check failed)" : "");
|
| +}
|
|
|