SDP Security descriptions. More...
#include "asterisk.h"
#include "asterisk/options.h"
#include "asterisk/utils.h"
#include "include/sdp_crypto.h"
Go to the source code of this file.
Data Structures | |
struct | sdp_crypto |
Defines | |
#define | SRTP_MASTER_LEN 30 |
#define | SRTP_MASTER_LEN64 (((SRTP_MASTER_LEN) * 8 + 5) / 6 + 1) |
#define | SRTP_MASTERKEY_LEN 16 |
#define | SRTP_MASTERSALT_LEN ((SRTP_MASTER_LEN) - (SRTP_MASTERKEY_LEN)) |
Functions | |
static int | sdp_crypto_activate (struct sdp_crypto *p, int suite_val, unsigned char *remote_key, struct ast_rtp_instance *rtp) |
static struct sdp_crypto * | sdp_crypto_alloc (void) |
const char * | sdp_crypto_attrib (struct sdp_crypto *p) |
void | sdp_crypto_destroy (struct sdp_crypto *crypto) |
int | sdp_crypto_offer (struct sdp_crypto *p) |
int | sdp_crypto_process (struct sdp_crypto *p, const char *attr, struct ast_rtp_instance *rtp) |
struct sdp_crypto * | sdp_crypto_setup (void) |
static int | set_crypto_policy (struct ast_srtp_policy *policy, int suite_val, const unsigned char *master_key, unsigned long ssrc, int inbound) |
Variables | |
struct ast_srtp_res * | res_srtp |
struct ast_srtp_policy_res * | res_srtp_policy |
SDP Security descriptions.
Specified in RFC 4568
Definition in file sdp_crypto.c.
#define SRTP_MASTER_LEN 30 |
Definition at line 40 of file sdp_crypto.c.
Referenced by sdp_crypto_process(), and sdp_crypto_setup().
#define SRTP_MASTER_LEN64 (((SRTP_MASTER_LEN) * 8 + 5) / 6 + 1) |
Definition at line 43 of file sdp_crypto.c.
#define SRTP_MASTERKEY_LEN 16 |
Definition at line 41 of file sdp_crypto.c.
Referenced by set_crypto_policy().
#define SRTP_MASTERSALT_LEN ((SRTP_MASTER_LEN) - (SRTP_MASTERKEY_LEN)) |
Definition at line 42 of file sdp_crypto.c.
Referenced by set_crypto_policy().
static int sdp_crypto_activate | ( | struct sdp_crypto * | p, | |
int | suite_val, | |||
unsigned char * | remote_key, | |||
struct ast_rtp_instance * | rtp | |||
) | [static] |
Definition at line 136 of file sdp_crypto.c.
References ast_srtp_policy_res::alloc, ast_debug, ast_log(), ast_rtp_engine_srtp_is_registered(), ast_rtp_instance_add_srtp_policy(), ast_rtp_instance_get_stats(), AST_RTP_INSTANCE_STAT_LOCAL_SSRC, ast_srtp_policy_res::destroy, sdp_crypto::local_key, ast_rtp_instance_stats::local_ssrc, LOG_WARNING, and set_crypto_policy().
Referenced by sdp_crypto_process().
00137 { 00138 struct ast_srtp_policy *local_policy = NULL; 00139 struct ast_srtp_policy *remote_policy = NULL; 00140 struct ast_rtp_instance_stats stats = {0,}; 00141 int res = -1; 00142 00143 if (!ast_rtp_engine_srtp_is_registered()) { 00144 return -1; 00145 } 00146 00147 if (!p) { 00148 return -1; 00149 } 00150 00151 if (!(local_policy = res_srtp_policy->alloc())) { 00152 return -1; 00153 } 00154 00155 if (!(remote_policy = res_srtp_policy->alloc())) { 00156 goto err; 00157 } 00158 00159 if (ast_rtp_instance_get_stats(rtp, &stats, AST_RTP_INSTANCE_STAT_LOCAL_SSRC)) { 00160 goto err; 00161 } 00162 00163 if (set_crypto_policy(local_policy, suite_val, p->local_key, stats.local_ssrc, 0) < 0) { 00164 goto err; 00165 } 00166 00167 if (set_crypto_policy(remote_policy, suite_val, remote_key, 0, 1) < 0) { 00168 goto err; 00169 } 00170 00171 /* Add the SRTP policies */ 00172 if (ast_rtp_instance_add_srtp_policy(rtp, remote_policy, local_policy)) { 00173 ast_log(LOG_WARNING, "Could not set SRTP policies\n"); 00174 goto err; 00175 } 00176 00177 ast_debug(1 , "SRTP policy activated\n"); 00178 res = 0; 00179 00180 err: 00181 if (local_policy) { 00182 res_srtp_policy->destroy(local_policy); 00183 } 00184 00185 if (remote_policy) { 00186 res_srtp_policy->destroy(remote_policy); 00187 } 00188 00189 return res; 00190 }
static struct sdp_crypto* sdp_crypto_alloc | ( | void | ) | [static, read] |
Definition at line 59 of file sdp_crypto.c.
References ast_calloc.
Referenced by sdp_crypto_setup().
00060 { 00061 return ast_calloc(1, sizeof(struct sdp_crypto)); 00062 }
const char* sdp_crypto_attrib | ( | struct sdp_crypto * | p | ) |
Definition at line 318 of file sdp_crypto.c.
References sdp_crypto::a_crypto.
Referenced by get_crypto_attrib().
00319 { 00320 return p->a_crypto; 00321 }
void sdp_crypto_destroy | ( | struct sdp_crypto * | crypto | ) |
Definition at line 64 of file sdp_crypto.c.
References sdp_crypto::a_crypto, ast_free, and sdp_crypto::tag.
Referenced by sdp_crypto_setup(), and sip_srtp_destroy().
int sdp_crypto_offer | ( | struct sdp_crypto * | p | ) |
Definition at line 295 of file sdp_crypto.c.
References sdp_crypto::a_crypto, ast_asprintf, ast_free, ast_log(), ast_strlen_zero(), sdp_crypto::local_key64, LOG_DEBUG, LOG_ERROR, sdp_crypto::suite, and sdp_crypto::tag.
Referenced by get_crypto_attrib(), and sdp_crypto_process().
00296 { 00297 if (ast_strlen_zero(p->suite)) { 00298 /* Default crypto offer */ 00299 strcpy(p->suite, "AES_CM_128_HMAC_SHA1_80"); 00300 } 00301 00302 /* Rebuild the crypto line */ 00303 if (p->a_crypto) { 00304 ast_free(p->a_crypto); 00305 } 00306 00307 if (ast_asprintf(&p->a_crypto, "a=crypto:%s %s inline:%s\r\n", 00308 p->tag ? p->tag : "1", p->suite, p->local_key64) == -1) { 00309 ast_log(LOG_ERROR, "Could not allocate memory for crypto line\n"); 00310 return -1; 00311 } 00312 00313 ast_log(LOG_DEBUG, "Crypto line: %s", p->a_crypto); 00314 00315 return 0; 00316 }
int sdp_crypto_process | ( | struct sdp_crypto * | p, | |
const char * | attr, | |||
struct ast_rtp_instance * | rtp | |||
) |
Definition at line 192 of file sdp_crypto.c.
References AST_AES_CM_128_HMAC_SHA1_32, AST_AES_CM_128_HMAC_SHA1_80, ast_base64decode(), ast_copy_string(), ast_debug, ast_log(), ast_rtp_engine_srtp_is_registered(), ast_strdup, ast_strdupa, LOG_DEBUG, LOG_ERROR, LOG_NOTICE, LOG_WARNING, sdp_crypto::remote_key, sdp_crypto_activate(), sdp_crypto_offer(), SRTP_MASTER_LEN, str, sdp_crypto::suite, and sdp_crypto::tag.
Referenced by process_crypto().
00193 { 00194 char *str = NULL; 00195 char *tag = NULL; 00196 char *suite = NULL; 00197 char *key_params = NULL; 00198 char *key_param = NULL; 00199 char *session_params = NULL; 00200 char *key_salt = NULL; 00201 char *lifetime = NULL; 00202 int found = 0; 00203 int key_len = 0; 00204 int suite_val = 0; 00205 unsigned char remote_key[SRTP_MASTER_LEN]; 00206 00207 if (!ast_rtp_engine_srtp_is_registered()) { 00208 return -1; 00209 } 00210 00211 str = ast_strdupa(attr); 00212 00213 strsep(&str, ":"); 00214 tag = strsep(&str, " "); 00215 suite = strsep(&str, " "); 00216 key_params = strsep(&str, " "); 00217 session_params = strsep(&str, " "); 00218 00219 if (!tag || !suite) { 00220 ast_log(LOG_WARNING, "Unrecognized a=%s", attr); 00221 return -1; 00222 } 00223 00224 if (session_params) { 00225 ast_log(LOG_WARNING, "Unsupported crypto parameters: %s", session_params); 00226 return -1; 00227 } 00228 00229 if (!strcmp(suite, "AES_CM_128_HMAC_SHA1_80")) { 00230 suite_val = AST_AES_CM_128_HMAC_SHA1_80; 00231 } else if (!strcmp(suite, "AES_CM_128_HMAC_SHA1_32")) { 00232 suite_val = AST_AES_CM_128_HMAC_SHA1_32; 00233 } else { 00234 ast_log(LOG_WARNING, "Unsupported crypto suite: %s\n", suite); 00235 return -1; 00236 } 00237 00238 while ((key_param = strsep(&key_params, ";"))) { 00239 char *method = NULL; 00240 char *info = NULL; 00241 00242 method = strsep(&key_param, ":"); 00243 info = strsep(&key_param, ";"); 00244 00245 if (!strcmp(method, "inline")) { 00246 key_salt = strsep(&info, "|"); 00247 lifetime = strsep(&info, "|"); 00248 00249 if (lifetime) { 00250 ast_log(LOG_NOTICE, "Crypto life time unsupported: %s\n", attr); 00251 continue; 00252 } 00253 00254 found = 1; 00255 break; 00256 } 00257 } 00258 00259 if (!found) { 00260 ast_log(LOG_NOTICE, "SRTP crypto offer not acceptable\n"); 00261 return -1; 00262 } 00263 00264 if ((key_len = ast_base64decode(remote_key, key_salt, sizeof(remote_key))) != SRTP_MASTER_LEN) { 00265 ast_log(LOG_WARNING, "SRTP descriptions key %d != %d\n", key_len, SRTP_MASTER_LEN); 00266 return -1; 00267 } 00268 00269 if (!memcmp(p->remote_key, remote_key, sizeof(p->remote_key))) { 00270 ast_debug(1, "SRTP remote key unchanged; maintaining current policy\n"); 00271 return 0; 00272 } 00273 00274 /* Set the accepted policy and remote key */ 00275 ast_copy_string(p->suite, suite, sizeof(p->suite)); 00276 memcpy(p->remote_key, remote_key, sizeof(p->remote_key)); 00277 00278 if (sdp_crypto_activate(p, suite_val, remote_key, rtp) < 0) { 00279 return -1; 00280 } 00281 00282 if (!p->tag) { 00283 ast_log(LOG_DEBUG, "Accepting crypto tag %s\n", tag); 00284 p->tag = ast_strdup(tag); 00285 if (!p->tag) { 00286 ast_log(LOG_ERROR, "Could not allocate memory for tag\n"); 00287 return -1; 00288 } 00289 } 00290 00291 /* Finally, rebuild the crypto line */ 00292 return sdp_crypto_offer(p); 00293 }
struct sdp_crypto* sdp_crypto_setup | ( | void | ) | [read] |
Definition at line 73 of file sdp_crypto.c.
References ast_base64decode(), ast_base64encode(), ast_debug, ast_free, ast_log(), ast_rtp_engine_srtp_is_registered(), ast_srtp_res::get_random, sdp_crypto::local_key, sdp_crypto::local_key64, LOG_ERROR, sdp_crypto::remote_key, sdp_crypto_alloc(), sdp_crypto_destroy(), and SRTP_MASTER_LEN.
Referenced by get_crypto_attrib(), and process_crypto().
00074 { 00075 struct sdp_crypto *p; 00076 int key_len; 00077 unsigned char remote_key[SRTP_MASTER_LEN]; 00078 00079 if (!ast_rtp_engine_srtp_is_registered()) { 00080 return NULL; 00081 } 00082 00083 if (!(p = sdp_crypto_alloc())) { 00084 return NULL; 00085 } 00086 00087 if (res_srtp->get_random(p->local_key, sizeof(p->local_key)) < 0) { 00088 sdp_crypto_destroy(p); 00089 return NULL; 00090 } 00091 00092 ast_base64encode(p->local_key64, p->local_key, SRTP_MASTER_LEN, sizeof(p->local_key64)); 00093 00094 key_len = ast_base64decode(remote_key, p->local_key64, sizeof(remote_key)); 00095 00096 if (key_len != SRTP_MASTER_LEN) { 00097 ast_log(LOG_ERROR, "base64 encode/decode bad len %d != %d\n", key_len, SRTP_MASTER_LEN); 00098 ast_free(p); 00099 return NULL; 00100 } 00101 00102 if (memcmp(remote_key, p->local_key, SRTP_MASTER_LEN)) { 00103 ast_log(LOG_ERROR, "base64 encode/decode bad key\n"); 00104 ast_free(p); 00105 return NULL; 00106 } 00107 00108 ast_debug(1 , "local_key64 %s len %zu\n", p->local_key64, strlen(p->local_key64)); 00109 00110 return p; 00111 }
static int set_crypto_policy | ( | struct ast_srtp_policy * | policy, | |
int | suite_val, | |||
const unsigned char * | master_key, | |||
unsigned long | ssrc, | |||
int | inbound | |||
) | [static] |
Definition at line 113 of file sdp_crypto.c.
References ast_log(), ast_rtp_engine_srtp_is_registered(), LOG_WARNING, ast_srtp_policy_res::set_master_key, ast_srtp_policy_res::set_ssrc, ast_srtp_policy_res::set_suite, SRTP_MASTERKEY_LEN, and SRTP_MASTERSALT_LEN.
Referenced by sdp_crypto_activate().
00114 { 00115 const unsigned char *master_salt = NULL; 00116 00117 if (!ast_rtp_engine_srtp_is_registered()) { 00118 return -1; 00119 } 00120 00121 master_salt = master_key + SRTP_MASTERKEY_LEN; 00122 if (res_srtp_policy->set_master_key(policy, master_key, SRTP_MASTERKEY_LEN, master_salt, SRTP_MASTERSALT_LEN) < 0) { 00123 return -1; 00124 } 00125 00126 if (res_srtp_policy->set_suite(policy, suite_val)) { 00127 ast_log(LOG_WARNING, "Could not set remote SRTP suite\n"); 00128 return -1; 00129 } 00130 00131 res_srtp_policy->set_ssrc(policy, ssrc, inbound); 00132 00133 return 0; 00134 }
struct ast_srtp_res* res_srtp |
Definition at line 48 of file rtp_engine.c.
struct ast_srtp_policy_res* res_srtp_policy |
Definition at line 49 of file rtp_engine.c.