1 /* $OpenBSD: tls_server.c,v 1.33 2017/01/24 01:48:05 claudio Exp $ */ 2 /* 3 * Copyright (c) 2014 Joel Sing <jsing@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <sys/socket.h> 19 20 #include <arpa/inet.h> 21 22 #include <openssl/ec.h> 23 #include <openssl/err.h> 24 #include <openssl/ssl.h> 25 26 #include <tls.h> 27 #include "tls_internal.h" 28 29 struct tls * 30 tls_server(void) 31 { 32 struct tls *ctx; 33 34 if ((ctx = tls_new()) == NULL) 35 return (NULL); 36 37 ctx->flags |= TLS_SERVER; 38 39 return (ctx); 40 } 41 42 struct tls * 43 tls_server_conn(struct tls *ctx) 44 { 45 struct tls *conn_ctx; 46 47 if ((conn_ctx = tls_new()) == NULL) 48 return (NULL); 49 50 conn_ctx->flags |= TLS_SERVER_CONN; 51 conn_ctx->config = ctx->config; 52 53 return (conn_ctx); 54 } 55 56 static int 57 tls_server_alpn_cb(SSL *ssl, const unsigned char **out, unsigned char *outlen, 58 const unsigned char *in, unsigned int inlen, void *arg) 59 { 60 struct tls *ctx = arg; 61 62 if (SSL_select_next_proto((unsigned char**)out, outlen, 63 ctx->config->alpn, ctx->config->alpn_len, in, inlen) == 64 OPENSSL_NPN_NEGOTIATED) 65 return (SSL_TLSEXT_ERR_OK); 66 67 return (SSL_TLSEXT_ERR_NOACK); 68 } 69 70 static int 71 tls_servername_cb(SSL *ssl, int *al, void *arg) 72 { 73 struct tls *ctx = (struct tls *)arg; 74 struct tls_sni_ctx *sni_ctx; 75 union tls_addr addrbuf; 76 struct tls *conn_ctx; 77 const char *name; 78 79 if ((conn_ctx = SSL_get_app_data(ssl)) == NULL) 80 goto err; 81 82 if ((name = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name)) == NULL) { 83 /* 84 * The servername callback gets called even when there is no 85 * TLS servername extension provided by the client. Sigh! 86 */ 87 return (SSL_TLSEXT_ERR_NOACK); 88 } 89 90 /* Per RFC 6066 section 3: ensure that name is not an IP literal. */ 91 if (inet_pton(AF_INET, name, &addrbuf) == 1 || 92 inet_pton(AF_INET6, name, &addrbuf) == 1) 93 goto err; 94 95 free((char *)conn_ctx->servername); 96 if ((conn_ctx->servername = strdup(name)) == NULL) 97 goto err; 98 99 /* Find appropriate SSL context for requested servername. */ 100 for (sni_ctx = ctx->sni_ctx; sni_ctx != NULL; sni_ctx = sni_ctx->next) { 101 if (tls_check_name(ctx, sni_ctx->ssl_cert, name) == 0) { 102 SSL_set_SSL_CTX(conn_ctx->ssl_conn, sni_ctx->ssl_ctx); 103 return (SSL_TLSEXT_ERR_OK); 104 } 105 } 106 107 /* No match, use the existing context/certificate. */ 108 return (SSL_TLSEXT_ERR_OK); 109 110 err: 111 /* 112 * There is no way to tell libssl that an internal failure occurred. 113 * The only option we have is to return a fatal alert. 114 */ 115 *al = TLS1_AD_INTERNAL_ERROR; 116 return (SSL_TLSEXT_ERR_ALERT_FATAL); 117 } 118 119 static struct tls_ticket_key * 120 tls_server_ticket_key(struct tls_config *config, unsigned char *keyname) 121 { 122 struct tls_ticket_key *key = NULL; 123 time_t now; 124 int i; 125 126 now = time(NULL); 127 if (config->ticket_autorekey == 1) { 128 if (now - 3 * (config->session_lifetime / 4) > 129 config->ticket_keys[0].time) { 130 if (tls_config_ticket_autorekey(config) == -1) 131 return (NULL); 132 } 133 } 134 for (i = 0; i < TLS_NUM_TICKETS; i++) { 135 struct tls_ticket_key *tk = &config->ticket_keys[i]; 136 if (now - config->session_lifetime > tk->time) 137 continue; 138 if (keyname == NULL || timingsafe_memcmp(keyname, 139 tk->key_name, sizeof(tk->key_name)) == 0) { 140 key = tk; 141 break; 142 } 143 } 144 return (key); 145 } 146 147 static int 148 tls_server_ticket_cb(SSL *ssl, unsigned char *keyname, unsigned char *iv, 149 EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx, int mode) 150 { 151 struct tls_ticket_key *key; 152 struct tls *tls_ctx; 153 154 if ((tls_ctx = SSL_get_app_data(ssl)) == NULL) 155 return (-1); 156 157 if (mode == 1) { 158 /* create new session */ 159 key = tls_server_ticket_key(tls_ctx->config, NULL); 160 if (key == NULL) { 161 tls_set_errorx(tls_ctx, "no valid ticket key found"); 162 return (-1); 163 } 164 165 memcpy(keyname, key->key_name, sizeof(key->key_name)); 166 arc4random_buf(iv, EVP_MAX_IV_LENGTH); 167 EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, 168 key->aes_key, iv); 169 HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key), 170 EVP_sha256(), NULL); 171 return (0); 172 } else { 173 /* get key by name */ 174 key = tls_server_ticket_key(tls_ctx->config, keyname); 175 if (key == NULL) 176 return (0); 177 178 EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, 179 key->aes_key, iv); 180 HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key), 181 EVP_sha256(), NULL); 182 183 /* time to renew the ticket? is it the primary key? */ 184 if (key != &tls_ctx->config->ticket_keys[0]) 185 return (2); 186 return (1); 187 } 188 } 189 190 static int 191 tls_keypair_load_cert(struct tls_keypair *keypair, struct tls_error *error, 192 X509 **cert) 193 { 194 char *errstr = "unknown"; 195 BIO *cert_bio = NULL; 196 int ssl_err; 197 198 X509_free(*cert); 199 *cert = NULL; 200 201 if (keypair->cert_mem == NULL) { 202 tls_error_set(error, "keypair has no certificate"); 203 goto err; 204 } 205 if ((cert_bio = BIO_new_mem_buf(keypair->cert_mem, 206 keypair->cert_len)) == NULL) { 207 tls_error_set(error, "failed to create certificate bio"); 208 goto err; 209 } 210 if ((*cert = PEM_read_bio_X509(cert_bio, NULL, NULL, NULL)) == NULL) { 211 if ((ssl_err = ERR_peek_error()) != 0) 212 errstr = ERR_error_string(ssl_err, NULL); 213 tls_error_set(error, "failed to load certificate: %s", errstr); 214 goto err; 215 } 216 217 BIO_free(cert_bio); 218 219 return (0); 220 221 err: 222 BIO_free(cert_bio); 223 224 return (-1); 225 } 226 227 static int 228 tls_configure_server_ssl(struct tls *ctx, SSL_CTX **ssl_ctx, 229 struct tls_keypair *keypair) 230 { 231 EC_KEY *ecdh_key; 232 233 SSL_CTX_free(*ssl_ctx); 234 235 if ((*ssl_ctx = SSL_CTX_new(SSLv23_server_method())) == NULL) { 236 tls_set_errorx(ctx, "ssl context failure"); 237 goto err; 238 } 239 240 if (SSL_CTX_set_tlsext_servername_callback(*ssl_ctx, 241 tls_servername_cb) != 1) { 242 tls_set_error(ctx, "failed to set servername callback"); 243 goto err; 244 } 245 if (SSL_CTX_set_tlsext_servername_arg(*ssl_ctx, ctx) != 1) { 246 tls_set_error(ctx, "failed to set servername callback arg"); 247 goto err; 248 } 249 250 if (tls_configure_ssl(ctx, *ssl_ctx) != 0) 251 goto err; 252 if (tls_configure_ssl_keypair(ctx, *ssl_ctx, keypair, 1) != 0) 253 goto err; 254 if (ctx->config->verify_client != 0) { 255 int verify = SSL_VERIFY_PEER; 256 if (ctx->config->verify_client == 1) 257 verify |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT; 258 if (tls_configure_ssl_verify(ctx, *ssl_ctx, verify) == -1) 259 goto err; 260 } 261 262 if (ctx->config->alpn != NULL) 263 SSL_CTX_set_alpn_select_cb(*ssl_ctx, tls_server_alpn_cb, 264 ctx); 265 266 if (ctx->config->dheparams == -1) 267 SSL_CTX_set_dh_auto(*ssl_ctx, 1); 268 else if (ctx->config->dheparams == 1024) 269 SSL_CTX_set_dh_auto(*ssl_ctx, 2); 270 271 if (ctx->config->ecdhecurve == -1) { 272 SSL_CTX_set_ecdh_auto(*ssl_ctx, 1); 273 } else if (ctx->config->ecdhecurve != NID_undef) { 274 if ((ecdh_key = EC_KEY_new_by_curve_name( 275 ctx->config->ecdhecurve)) == NULL) { 276 tls_set_errorx(ctx, "failed to set ECDHE curve"); 277 goto err; 278 } 279 SSL_CTX_set_options(*ssl_ctx, SSL_OP_SINGLE_ECDH_USE); 280 SSL_CTX_set_tmp_ecdh(*ssl_ctx, ecdh_key); 281 EC_KEY_free(ecdh_key); 282 } 283 284 if (ctx->config->ciphers_server == 1) 285 SSL_CTX_set_options(*ssl_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE); 286 287 if (SSL_CTX_set_tlsext_status_cb(*ssl_ctx, tls_ocsp_stapling_cb) != 1) { 288 tls_set_errorx(ctx, "failed to add OCSP stapling callback"); 289 goto err; 290 } 291 292 if (ctx->config->session_lifetime > 0) { 293 /* set the session lifetime and enable tickets */ 294 SSL_CTX_set_timeout(*ssl_ctx, ctx->config->session_lifetime); 295 SSL_CTX_clear_options(*ssl_ctx, SSL_OP_NO_TICKET); 296 if (!SSL_CTX_set_tlsext_ticket_key_cb(*ssl_ctx, 297 tls_server_ticket_cb)) { 298 tls_set_error(ctx, 299 "failed to set the TLS ticket callback"); 300 goto err; 301 } 302 } 303 304 if (SSL_CTX_set_session_id_context(*ssl_ctx, ctx->config->session_id, 305 sizeof(ctx->config->session_id)) != 1) { 306 tls_set_error(ctx, "failed to set session id context"); 307 goto err; 308 } 309 310 return (0); 311 312 err: 313 SSL_CTX_free(*ssl_ctx); 314 *ssl_ctx = NULL; 315 316 return (-1); 317 } 318 319 static int 320 tls_configure_server_sni(struct tls *ctx) 321 { 322 struct tls_sni_ctx **sni_ctx; 323 struct tls_keypair *kp; 324 325 if (ctx->config->keypair->next == NULL) 326 return (0); 327 328 /* Set up additional SSL contexts for SNI. */ 329 sni_ctx = &ctx->sni_ctx; 330 for (kp = ctx->config->keypair->next; kp != NULL; kp = kp->next) { 331 if ((*sni_ctx = tls_sni_ctx_new()) == NULL) { 332 tls_set_errorx(ctx, "out of memory"); 333 goto err; 334 } 335 if (tls_configure_server_ssl(ctx, &(*sni_ctx)->ssl_ctx, kp) == -1) 336 goto err; 337 if (tls_keypair_load_cert(kp, &ctx->error, 338 &(*sni_ctx)->ssl_cert) == -1) 339 goto err; 340 sni_ctx = &(*sni_ctx)->next; 341 } 342 343 return (0); 344 345 err: 346 return (-1); 347 } 348 349 int 350 tls_configure_server(struct tls *ctx) 351 { 352 if (tls_configure_server_ssl(ctx, &ctx->ssl_ctx, 353 ctx->config->keypair) == -1) 354 goto err; 355 if (tls_configure_server_sni(ctx) == -1) 356 goto err; 357 358 return (0); 359 360 err: 361 return (-1); 362 } 363 364 static struct tls * 365 tls_accept_common(struct tls *ctx) 366 { 367 struct tls *conn_ctx = NULL; 368 369 if ((ctx->flags & TLS_SERVER) == 0) { 370 tls_set_errorx(ctx, "not a server context"); 371 goto err; 372 } 373 374 if ((conn_ctx = tls_server_conn(ctx)) == NULL) { 375 tls_set_errorx(ctx, "connection context failure"); 376 goto err; 377 } 378 379 if ((conn_ctx->ssl_conn = SSL_new(ctx->ssl_ctx)) == NULL) { 380 tls_set_errorx(ctx, "ssl failure"); 381 goto err; 382 } 383 384 if (SSL_set_app_data(conn_ctx->ssl_conn, conn_ctx) != 1) { 385 tls_set_errorx(ctx, "ssl application data failure"); 386 goto err; 387 } 388 389 return conn_ctx; 390 391 err: 392 tls_free(conn_ctx); 393 394 return (NULL); 395 } 396 397 int 398 tls_accept_socket(struct tls *ctx, struct tls **cctx, int s) 399 { 400 return (tls_accept_fds(ctx, cctx, s, s)); 401 } 402 403 int 404 tls_accept_fds(struct tls *ctx, struct tls **cctx, int fd_read, int fd_write) 405 { 406 struct tls *conn_ctx; 407 408 if ((conn_ctx = tls_accept_common(ctx)) == NULL) 409 goto err; 410 411 if (SSL_set_rfd(conn_ctx->ssl_conn, fd_read) != 1 || 412 SSL_set_wfd(conn_ctx->ssl_conn, fd_write) != 1) { 413 tls_set_errorx(ctx, "ssl file descriptor failure"); 414 goto err; 415 } 416 417 *cctx = conn_ctx; 418 419 return (0); 420 err: 421 tls_free(conn_ctx); 422 *cctx = NULL; 423 424 return (-1); 425 } 426 427 int 428 tls_accept_cbs(struct tls *ctx, struct tls **cctx, 429 tls_read_cb read_cb, tls_write_cb write_cb, void *cb_arg) 430 { 431 struct tls *conn_ctx; 432 433 if ((conn_ctx = tls_accept_common(ctx)) == NULL) 434 goto err; 435 436 if (tls_set_cbs(conn_ctx, read_cb, write_cb, cb_arg) != 0) 437 goto err; 438 439 *cctx = conn_ctx; 440 441 return (0); 442 err: 443 tls_free(conn_ctx); 444 *cctx = NULL; 445 446 return (-1); 447 } 448 449 int 450 tls_handshake_server(struct tls *ctx) 451 { 452 int ssl_ret; 453 int rv = -1; 454 455 if ((ctx->flags & TLS_SERVER_CONN) == 0) { 456 tls_set_errorx(ctx, "not a server connection context"); 457 goto err; 458 } 459 460 ERR_clear_error(); 461 if ((ssl_ret = SSL_accept(ctx->ssl_conn)) != 1) { 462 rv = tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "handshake"); 463 goto err; 464 } 465 466 ctx->state |= TLS_HANDSHAKE_COMPLETE; 467 rv = 0; 468 469 err: 470 return (rv); 471 } 472