1 /* 2 * Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 /* 11 * DTLS code by Eric Rescorla <ekr@rtfm.com> 12 * 13 * Copyright (C) 2006, Network Resonance, Inc. Copyright (C) 2011, RTFM, Inc. 14 */ 15 16 #include <stdio.h> 17 #include <openssl/objects.h> 18 #include "ssl_locl.h" 19 20 #ifndef OPENSSL_NO_SRTP 21 22 static SRTP_PROTECTION_PROFILE srtp_known_profiles[] = { 23 { 24 "SRTP_AES128_CM_SHA1_80", 25 SRTP_AES128_CM_SHA1_80, 26 }, 27 { 28 "SRTP_AES128_CM_SHA1_32", 29 SRTP_AES128_CM_SHA1_32, 30 }, 31 { 32 "SRTP_AEAD_AES_128_GCM", 33 SRTP_AEAD_AES_128_GCM, 34 }, 35 { 36 "SRTP_AEAD_AES_256_GCM", 37 SRTP_AEAD_AES_256_GCM, 38 }, 39 {0} 40 }; 41 42 static int find_profile_by_name(char *profile_name, 43 SRTP_PROTECTION_PROFILE **pptr, unsigned len) 44 { 45 SRTP_PROTECTION_PROFILE *p; 46 47 p = srtp_known_profiles; 48 while (p->name) { 49 if ((len == strlen(p->name)) 50 && strncmp(p->name, profile_name, len) == 0) { 51 *pptr = p; 52 return 0; 53 } 54 55 p++; 56 } 57 58 return 1; 59 } 60 61 static int ssl_ctx_make_profiles(const char *profiles_string, 62 STACK_OF(SRTP_PROTECTION_PROFILE) **out) 63 { 64 STACK_OF(SRTP_PROTECTION_PROFILE) *profiles; 65 66 char *col; 67 char *ptr = (char *)profiles_string; 68 SRTP_PROTECTION_PROFILE *p; 69 70 if ((profiles = sk_SRTP_PROTECTION_PROFILE_new_null()) == NULL) { 71 SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES, 72 SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES); 73 return 1; 74 } 75 76 do { 77 col = strchr(ptr, ':'); 78 79 if (!find_profile_by_name(ptr, &p, col ? col - ptr : (int)strlen(ptr))) { 80 if (sk_SRTP_PROTECTION_PROFILE_find(profiles, p) >= 0) { 81 SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES, 82 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 83 goto err; 84 } 85 86 if (!sk_SRTP_PROTECTION_PROFILE_push(profiles, p)) { 87 SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES, 88 SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES); 89 goto err; 90 } 91 } else { 92 SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES, 93 SSL_R_SRTP_UNKNOWN_PROTECTION_PROFILE); 94 goto err; 95 } 96 97 if (col) 98 ptr = col + 1; 99 } while (col); 100 101 sk_SRTP_PROTECTION_PROFILE_free(*out); 102 103 *out = profiles; 104 105 return 0; 106 err: 107 sk_SRTP_PROTECTION_PROFILE_free(profiles); 108 return 1; 109 } 110 111 int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx, const char *profiles) 112 { 113 return ssl_ctx_make_profiles(profiles, &ctx->srtp_profiles); 114 } 115 116 int SSL_set_tlsext_use_srtp(SSL *s, const char *profiles) 117 { 118 return ssl_ctx_make_profiles(profiles, &s->srtp_profiles); 119 } 120 121 STACK_OF(SRTP_PROTECTION_PROFILE) *SSL_get_srtp_profiles(SSL *s) 122 { 123 if (s != NULL) { 124 if (s->srtp_profiles != NULL) { 125 return s->srtp_profiles; 126 } else if ((s->ctx != NULL) && (s->ctx->srtp_profiles != NULL)) { 127 return s->ctx->srtp_profiles; 128 } 129 } 130 131 return NULL; 132 } 133 134 SRTP_PROTECTION_PROFILE *SSL_get_selected_srtp_profile(SSL *s) 135 { 136 return s->srtp_profile; 137 } 138 139 /* 140 * Note: this function returns 0 length if there are no profiles specified 141 */ 142 int ssl_add_clienthello_use_srtp_ext(SSL *s, unsigned char *p, int *len, 143 int maxlen) 144 { 145 int ct = 0; 146 int i; 147 STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = 0; 148 SRTP_PROTECTION_PROFILE *prof; 149 150 clnt = SSL_get_srtp_profiles(s); 151 ct = sk_SRTP_PROTECTION_PROFILE_num(clnt); /* -1 if clnt == 0 */ 152 153 if (p) { 154 if (ct == 0) { 155 SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_USE_SRTP_EXT, 156 SSL_R_EMPTY_SRTP_PROTECTION_PROFILE_LIST); 157 return 1; 158 } 159 160 if ((2 + ct * 2 + 1) > maxlen) { 161 SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_USE_SRTP_EXT, 162 SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG); 163 return 1; 164 } 165 166 /* Add the length */ 167 s2n(ct * 2, p); 168 for (i = 0; i < ct; i++) { 169 prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i); 170 s2n(prof->id, p); 171 } 172 173 /* Add an empty use_mki value */ 174 *p++ = 0; 175 } 176 177 *len = 2 + ct * 2 + 1; 178 179 return 0; 180 } 181 182 int ssl_parse_clienthello_use_srtp_ext(SSL *s, PACKET *pkt, int *al) 183 { 184 SRTP_PROTECTION_PROFILE *sprof; 185 STACK_OF(SRTP_PROTECTION_PROFILE) *srvr; 186 unsigned int ct, mki_len, id; 187 int i, srtp_pref; 188 PACKET subpkt; 189 190 /* Pull off the length of the cipher suite list and check it is even */ 191 if (!PACKET_get_net_2(pkt, &ct) 192 || (ct & 1) != 0 || !PACKET_get_sub_packet(pkt, &subpkt, ct)) { 193 SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT, 194 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 195 *al = SSL_AD_DECODE_ERROR; 196 return 1; 197 } 198 199 srvr = SSL_get_srtp_profiles(s); 200 s->srtp_profile = NULL; 201 /* Search all profiles for a match initially */ 202 srtp_pref = sk_SRTP_PROTECTION_PROFILE_num(srvr); 203 204 while (PACKET_remaining(&subpkt)) { 205 if (!PACKET_get_net_2(&subpkt, &id)) { 206 SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT, 207 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 208 *al = SSL_AD_DECODE_ERROR; 209 return 1; 210 } 211 212 /* 213 * Only look for match in profiles of higher preference than 214 * current match. 215 * If no profiles have been have been configured then this 216 * does nothing. 217 */ 218 for (i = 0; i < srtp_pref; i++) { 219 sprof = sk_SRTP_PROTECTION_PROFILE_value(srvr, i); 220 if (sprof->id == id) { 221 s->srtp_profile = sprof; 222 srtp_pref = i; 223 break; 224 } 225 } 226 } 227 228 /* 229 * Now extract the MKI value as a sanity check, but discard it for now 230 */ 231 if (!PACKET_get_1(pkt, &mki_len)) { 232 SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT, 233 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 234 *al = SSL_AD_DECODE_ERROR; 235 return 1; 236 } 237 238 if (!PACKET_forward(pkt, mki_len) 239 || PACKET_remaining(pkt)) { 240 SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT, 241 SSL_R_BAD_SRTP_MKI_VALUE); 242 *al = SSL_AD_DECODE_ERROR; 243 return 1; 244 } 245 246 return 0; 247 } 248 249 int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len, 250 int maxlen) 251 { 252 if (p) { 253 if (maxlen < 5) { 254 SSLerr(SSL_F_SSL_ADD_SERVERHELLO_USE_SRTP_EXT, 255 SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG); 256 return 1; 257 } 258 259 if (s->srtp_profile == 0) { 260 SSLerr(SSL_F_SSL_ADD_SERVERHELLO_USE_SRTP_EXT, 261 SSL_R_USE_SRTP_NOT_NEGOTIATED); 262 return 1; 263 } 264 s2n(2, p); 265 s2n(s->srtp_profile->id, p); 266 *p++ = 0; 267 } 268 *len = 5; 269 270 return 0; 271 } 272 273 int ssl_parse_serverhello_use_srtp_ext(SSL *s, PACKET *pkt, int *al) 274 { 275 unsigned int id, ct, mki; 276 int i; 277 278 STACK_OF(SRTP_PROTECTION_PROFILE) *clnt; 279 SRTP_PROTECTION_PROFILE *prof; 280 281 if (!PACKET_get_net_2(pkt, &ct) 282 || ct != 2 || !PACKET_get_net_2(pkt, &id) 283 || !PACKET_get_1(pkt, &mki) 284 || PACKET_remaining(pkt) != 0) { 285 SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT, 286 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 287 *al = SSL_AD_DECODE_ERROR; 288 return 1; 289 } 290 291 if (mki != 0) { 292 /* Must be no MKI, since we never offer one */ 293 SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT, 294 SSL_R_BAD_SRTP_MKI_VALUE); 295 *al = SSL_AD_ILLEGAL_PARAMETER; 296 return 1; 297 } 298 299 clnt = SSL_get_srtp_profiles(s); 300 301 /* Throw an error if the server gave us an unsolicited extension */ 302 if (clnt == NULL) { 303 SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT, 304 SSL_R_NO_SRTP_PROFILES); 305 *al = SSL_AD_DECODE_ERROR; 306 return 1; 307 } 308 309 /* 310 * Check to see if the server gave us something we support (and 311 * presumably offered) 312 */ 313 for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) { 314 prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i); 315 316 if (prof->id == id) { 317 s->srtp_profile = prof; 318 *al = 0; 319 return 0; 320 } 321 } 322 323 SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT, 324 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 325 *al = SSL_AD_DECODE_ERROR; 326 return 1; 327 } 328 329 #endif 330