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)" : ""); |
+} |