1 /* $OpenBSD: tls_server.c,v 1.32 2017/01/12 16:15:58 jsing 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 int 120 tls_keypair_load_cert(struct tls_keypair *keypair, struct tls_error *error, 121 X509 **cert) 122 { 123 char *errstr = "unknown"; 124 BIO *cert_bio = NULL; 125 int ssl_err; 126 127 X509_free(*cert); 128 *cert = NULL; 129 130 if (keypair->cert_mem == NULL) { 131 tls_error_set(error, "keypair has no certificate"); 132 goto err; 133 } 134 if ((cert_bio = BIO_new_mem_buf(keypair->cert_mem, 135 keypair->cert_len)) == NULL) { 136 tls_error_set(error, "failed to create certificate bio"); 137 goto err; 138 } 139 if ((*cert = PEM_read_bio_X509(cert_bio, NULL, NULL, NULL)) == NULL) { 140 if ((ssl_err = ERR_peek_error()) != 0) 141 errstr = ERR_error_string(ssl_err, NULL); 142 tls_error_set(error, "failed to load certificate: %s", errstr); 143 goto err; 144 } 145 146 BIO_free(cert_bio); 147 148 return (0); 149 150 err: 151 BIO_free(cert_bio); 152 153 return (-1); 154 } 155 156 static int 157 tls_configure_server_ssl(struct tls *ctx, SSL_CTX **ssl_ctx, 158 struct tls_keypair *keypair) 159 { 160 unsigned char sid[SSL_MAX_SSL_SESSION_ID_LENGTH]; 161 EC_KEY *ecdh_key; 162 163 SSL_CTX_free(*ssl_ctx); 164 165 if ((*ssl_ctx = SSL_CTX_new(SSLv23_server_method())) == NULL) { 166 tls_set_errorx(ctx, "ssl context failure"); 167 goto err; 168 } 169 170 if (SSL_CTX_set_tlsext_servername_callback(*ssl_ctx, 171 tls_servername_cb) != 1) { 172 tls_set_error(ctx, "failed to set servername callback"); 173 goto err; 174 } 175 if (SSL_CTX_set_tlsext_servername_arg(*ssl_ctx, ctx) != 1) { 176 tls_set_error(ctx, "failed to set servername callback arg"); 177 goto err; 178 } 179 180 if (tls_configure_ssl(ctx, *ssl_ctx) != 0) 181 goto err; 182 if (tls_configure_ssl_keypair(ctx, *ssl_ctx, keypair, 1) != 0) 183 goto err; 184 if (ctx->config->verify_client != 0) { 185 int verify = SSL_VERIFY_PEER; 186 if (ctx->config->verify_client == 1) 187 verify |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT; 188 if (tls_configure_ssl_verify(ctx, *ssl_ctx, verify) == -1) 189 goto err; 190 } 191 192 if (ctx->config->alpn != NULL) 193 SSL_CTX_set_alpn_select_cb(*ssl_ctx, tls_server_alpn_cb, 194 ctx); 195 196 if (ctx->config->dheparams == -1) 197 SSL_CTX_set_dh_auto(*ssl_ctx, 1); 198 else if (ctx->config->dheparams == 1024) 199 SSL_CTX_set_dh_auto(*ssl_ctx, 2); 200 201 if (ctx->config->ecdhecurve == -1) { 202 SSL_CTX_set_ecdh_auto(*ssl_ctx, 1); 203 } else if (ctx->config->ecdhecurve != NID_undef) { 204 if ((ecdh_key = EC_KEY_new_by_curve_name( 205 ctx->config->ecdhecurve)) == NULL) { 206 tls_set_errorx(ctx, "failed to set ECDHE curve"); 207 goto err; 208 } 209 SSL_CTX_set_options(*ssl_ctx, SSL_OP_SINGLE_ECDH_USE); 210 SSL_CTX_set_tmp_ecdh(*ssl_ctx, ecdh_key); 211 EC_KEY_free(ecdh_key); 212 } 213 214 if (ctx->config->ciphers_server == 1) 215 SSL_CTX_set_options(*ssl_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE); 216 217 if (SSL_CTX_set_tlsext_status_cb(*ssl_ctx, tls_ocsp_stapling_cb) != 1) { 218 tls_set_errorx(ctx, "failed to add OCSP stapling callback"); 219 goto err; 220 } 221 222 /* 223 * Set session ID context to a random value. We don't support 224 * persistent caching of sessions so it is OK to set a temporary 225 * session ID context that is valid during run time. 226 */ 227 arc4random_buf(sid, sizeof(sid)); 228 if (SSL_CTX_set_session_id_context(*ssl_ctx, sid, 229 sizeof(sid)) != 1) { 230 tls_set_error(ctx, "failed to set session id context"); 231 goto err; 232 } 233 234 return (0); 235 236 err: 237 SSL_CTX_free(*ssl_ctx); 238 *ssl_ctx = NULL; 239 240 return (-1); 241 } 242 243 static int 244 tls_configure_server_sni(struct tls *ctx) 245 { 246 struct tls_sni_ctx **sni_ctx; 247 struct tls_keypair *kp; 248 249 if (ctx->config->keypair->next == NULL) 250 return (0); 251 252 /* Set up additional SSL contexts for SNI. */ 253 sni_ctx = &ctx->sni_ctx; 254 for (kp = ctx->config->keypair->next; kp != NULL; kp = kp->next) { 255 if ((*sni_ctx = tls_sni_ctx_new()) == NULL) { 256 tls_set_errorx(ctx, "out of memory"); 257 goto err; 258 } 259 if (tls_configure_server_ssl(ctx, &(*sni_ctx)->ssl_ctx, kp) == -1) 260 goto err; 261 if (tls_keypair_load_cert(kp, &ctx->error, 262 &(*sni_ctx)->ssl_cert) == -1) 263 goto err; 264 sni_ctx = &(*sni_ctx)->next; 265 } 266 267 return (0); 268 269 err: 270 return (-1); 271 } 272 273 int 274 tls_configure_server(struct tls *ctx) 275 { 276 if (tls_configure_server_ssl(ctx, &ctx->ssl_ctx, 277 ctx->config->keypair) == -1) 278 goto err; 279 if (tls_configure_server_sni(ctx) == -1) 280 goto err; 281 282 return (0); 283 284 err: 285 return (-1); 286 } 287 288 static struct tls * 289 tls_accept_common(struct tls *ctx) 290 { 291 struct tls *conn_ctx = NULL; 292 293 if ((ctx->flags & TLS_SERVER) == 0) { 294 tls_set_errorx(ctx, "not a server context"); 295 goto err; 296 } 297 298 if ((conn_ctx = tls_server_conn(ctx)) == NULL) { 299 tls_set_errorx(ctx, "connection context failure"); 300 goto err; 301 } 302 303 if ((conn_ctx->ssl_conn = SSL_new(ctx->ssl_ctx)) == NULL) { 304 tls_set_errorx(ctx, "ssl failure"); 305 goto err; 306 } 307 308 if (SSL_set_app_data(conn_ctx->ssl_conn, conn_ctx) != 1) { 309 tls_set_errorx(ctx, "ssl application data failure"); 310 goto err; 311 } 312 313 return conn_ctx; 314 315 err: 316 tls_free(conn_ctx); 317 318 return (NULL); 319 } 320 321 int 322 tls_accept_socket(struct tls *ctx, struct tls **cctx, int s) 323 { 324 return (tls_accept_fds(ctx, cctx, s, s)); 325 } 326 327 int 328 tls_accept_fds(struct tls *ctx, struct tls **cctx, int fd_read, int fd_write) 329 { 330 struct tls *conn_ctx; 331 332 if ((conn_ctx = tls_accept_common(ctx)) == NULL) 333 goto err; 334 335 if (SSL_set_rfd(conn_ctx->ssl_conn, fd_read) != 1 || 336 SSL_set_wfd(conn_ctx->ssl_conn, fd_write) != 1) { 337 tls_set_errorx(ctx, "ssl file descriptor failure"); 338 goto err; 339 } 340 341 *cctx = conn_ctx; 342 343 return (0); 344 err: 345 tls_free(conn_ctx); 346 *cctx = NULL; 347 348 return (-1); 349 } 350 351 int 352 tls_accept_cbs(struct tls *ctx, struct tls **cctx, 353 tls_read_cb read_cb, tls_write_cb write_cb, void *cb_arg) 354 { 355 struct tls *conn_ctx; 356 357 if ((conn_ctx = tls_accept_common(ctx)) == NULL) 358 goto err; 359 360 if (tls_set_cbs(conn_ctx, read_cb, write_cb, cb_arg) != 0) 361 goto err; 362 363 *cctx = conn_ctx; 364 365 return (0); 366 err: 367 tls_free(conn_ctx); 368 *cctx = NULL; 369 370 return (-1); 371 } 372 373 int 374 tls_handshake_server(struct tls *ctx) 375 { 376 int ssl_ret; 377 int rv = -1; 378 379 if ((ctx->flags & TLS_SERVER_CONN) == 0) { 380 tls_set_errorx(ctx, "not a server connection context"); 381 goto err; 382 } 383 384 ERR_clear_error(); 385 if ((ssl_ret = SSL_accept(ctx->ssl_conn)) != 1) { 386 rv = tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "handshake"); 387 goto err; 388 } 389 390 ctx->state |= TLS_HANDSHAKE_COMPLETE; 391 rv = 0; 392 393 err: 394 return (rv); 395 } 396