1/*++ 2/* NAME 3/* tls_server 3 4/* SUMMARY 5/* server-side TLS engine 6/* SYNOPSIS 7/* #include <tls.h> 8/* 9/* TLS_APPL_STATE *tls_server_init(props) 10/* const TLS_SERVER_INIT_PROPS *props; 11/* 12/* TLS_SESS_STATE *tls_server_start(props) 13/* const TLS_SERVER_START_PROPS *props; 14/* 15/* TLS_SESS_STATE *tls_server_post_accept(TLScontext) 16/* TLS_SESS_STATE *TLScontext; 17/* 18/* void tls_server_stop(app_ctx, stream, failure, TLScontext) 19/* TLS_APPL_STATE *app_ctx; 20/* VSTREAM *stream; 21/* int failure; 22/* TLS_SESS_STATE *TLScontext; 23/* DESCRIPTION 24/* This module is the interface between Postfix TLS servers, 25/* the OpenSSL library, and the TLS entropy and cache manager. 26/* 27/* See "EVENT_DRIVEN APPLICATIONS" below for using this code 28/* in event-driven programs. 29/* 30/* tls_server_init() is called once when the SMTP server 31/* initializes. 32/* Certificate details are also decided during this phase, 33/* so that peer-specific behavior is not possible. 34/* 35/* tls_server_start() activates the TLS feature for the VSTREAM 36/* passed as argument. We assume that network buffers are flushed 37/* and the TLS handshake can begin immediately. 38/* 39/* tls_server_stop() sends the "close notify" alert via 40/* SSL_shutdown() to the peer and resets all connection specific 41/* TLS data. As RFC2487 does not specify a separate shutdown, it 42/* is assumed that the underlying TCP connection is shut down 43/* immediately afterwards. Any further writes to the channel will 44/* be discarded, and any further reads will report end-of-file. 45/* If the failure flag is set, no SSL_shutdown() handshake is performed. 46/* 47/* Once the TLS connection is initiated, information about the TLS 48/* state is available via the TLScontext structure: 49/* .IP TLScontext->protocol 50/* the protocol name (SSLv2, SSLv3, TLSv1), 51/* .IP TLScontext->cipher_name 52/* the cipher name (e.g. RC4/MD5), 53/* .IP TLScontext->cipher_usebits 54/* the number of bits actually used (e.g. 40), 55/* .IP TLScontext->cipher_algbits 56/* the number of bits the algorithm is based on (e.g. 128). 57/* .PP 58/* The last two values may differ from each other when export-strength 59/* encryption is used. 60/* 61/* If the peer offered a certificate, part of the certificate data are 62/* available as: 63/* .IP TLScontext->peer_status 64/* A bitmask field that records the status of the peer certificate 65/* verification. One or more of TLS_CERT_FLAG_PRESENT and 66/* TLS_CERT_FLAG_TRUSTED. 67/* .IP TLScontext->peer_CN 68/* Extracted CommonName of the peer, or zero-length string 69/* when information could not be extracted. 70/* .IP TLScontext->issuer_CN 71/* Extracted CommonName of the issuer, or zero-length string 72/* when information could not be extracted. 73/* .IP TLScontext->peer_fingerprint 74/* Fingerprint of the certificate, or zero-length string when no peer 75/* certificate is available. 76/* .PP 77/* If no peer certificate is presented the peer_status is set to 0. 78/* EVENT_DRIVEN APPLICATIONS 79/* .ad 80/* .fi 81/* Event-driven programs manage multiple I/O channels. Such 82/* programs cannot use the synchronous VSTREAM-over-TLS 83/* implementation that the current TLS library provides, 84/* including tls_server_stop() and the underlying tls_stream(3) 85/* and tls_bio_ops(3) routines. 86/* 87/* With the current TLS library implementation, this means 88/* that the application is responsible for calling and retrying 89/* SSL_accept(), SSL_read(), SSL_write() and SSL_shutdown(). 90/* 91/* To maintain control over TLS I/O, an event-driven server 92/* invokes tls_server_start() with a null VSTREAM argument and 93/* with an fd argument that specifies the I/O file descriptor. 94/* Then, tls_server_start() performs all the necessary 95/* preparations before the TLS handshake and returns a partially 96/* populated TLS context. The event-driven application is then 97/* responsible for invoking SSL_accept(), and if successful, 98/* for invoking tls_server_post_accept() to finish the work 99/* that was started by tls_server_start(). In case of unrecoverable 100/* failure, tls_server_post_accept() destroys the TLS context 101/* and returns a null pointer value. 102/* LICENSE 103/* .ad 104/* .fi 105/* This software is free. You can do with it whatever you want. 106/* The original author kindly requests that you acknowledge 107/* the use of his software. 108/* AUTHOR(S) 109/* Originally written by: 110/* Lutz Jaenicke 111/* BTU Cottbus 112/* Allgemeine Elektrotechnik 113/* Universitaetsplatz 3-4 114/* D-03044 Cottbus, Germany 115/* 116/* Updated by: 117/* Wietse Venema 118/* IBM T.J. Watson Research 119/* P.O. Box 704 120/* Yorktown Heights, NY 10598, USA 121/* 122/* Victor Duchovni 123/* Morgan Stanley 124/*--*/ 125 126/* System library. */ 127 128#include <sys_defs.h> 129 130#ifdef USE_TLS 131#include <unistd.h> 132#include <string.h> 133 134/* Utility library. */ 135 136#include <mymalloc.h> 137#include <vstring.h> 138#include <vstream.h> 139#include <dict.h> 140#include <stringops.h> 141#include <msg.h> 142#include <hex_code.h> 143#include <iostuff.h> /* non-blocking */ 144 145/* Global library. */ 146 147#include <mail_params.h> 148 149/* TLS library. */ 150 151#include <tls_mgr.h> 152#define TLS_INTERNAL 153#include <tls.h> 154 155#define STR(x) vstring_str(x) 156#define LEN(x) VSTRING_LEN(x) 157 158/* Application-specific. */ 159 160 /* 161 * The session_id_context indentifies the service that created a session. 162 * This information is used to distinguish between multiple TLS-based 163 * servers running on the same server. We use the name of the mail system. 164 */ 165static const char server_session_id_context[] = "Postfix/TLS"; 166 167/* get_server_session_cb - callback to retrieve session from server cache */ 168 169static SSL_SESSION *get_server_session_cb(SSL *ssl, unsigned char *session_id, 170 int session_id_length, 171 int *unused_copy) 172{ 173 const char *myname = "get_server_session_cb"; 174 TLS_SESS_STATE *TLScontext; 175 VSTRING *cache_id; 176 VSTRING *session_data = vstring_alloc(2048); 177 SSL_SESSION *session = 0; 178 179 if ((TLScontext = SSL_get_ex_data(ssl, TLScontext_index)) == 0) 180 msg_panic("%s: null TLScontext in session lookup callback", myname); 181 182#define GEN_CACHE_ID(buf, id, len, service) \ 183 do { \ 184 buf = vstring_alloc(2 * (len) + 1 + strlen(service) + 3); \ 185 hex_encode(buf, (char *) (id), (len)); \ 186 vstring_sprintf_append(buf, "&s=%s", (service)); \ 187 } while (0) 188 189 190 GEN_CACHE_ID(cache_id, session_id, session_id_length, TLScontext->serverid); 191 192 if (TLScontext->log_mask & TLS_LOG_CACHE) 193 msg_info("%s: looking up session %s in %s cache", TLScontext->namaddr, 194 STR(cache_id), TLScontext->cache_type); 195 196 /* 197 * Load the session from cache and decode it. 198 */ 199 if (tls_mgr_lookup(TLScontext->cache_type, STR(cache_id), 200 session_data) == TLS_MGR_STAT_OK) { 201 session = tls_session_activate(STR(session_data), LEN(session_data)); 202 if (session && (TLScontext->log_mask & TLS_LOG_CACHE)) 203 msg_info("%s: reloaded session %s from %s cache", 204 TLScontext->namaddr, STR(cache_id), 205 TLScontext->cache_type); 206 } 207 208 /* 209 * Clean up. 210 */ 211 vstring_free(cache_id); 212 vstring_free(session_data); 213 214 return (session); 215} 216 217/* uncache_session - remove session from internal & external cache */ 218 219static void uncache_session(SSL_CTX *ctx, TLS_SESS_STATE *TLScontext) 220{ 221 VSTRING *cache_id; 222 SSL_SESSION *session = SSL_get_session(TLScontext->con); 223 224 SSL_CTX_remove_session(ctx, session); 225 226 if (TLScontext->cache_type == 0) 227 return; 228 229 GEN_CACHE_ID(cache_id, session->session_id, session->session_id_length, 230 TLScontext->serverid); 231 232 if (TLScontext->log_mask & TLS_LOG_CACHE) 233 msg_info("%s: remove session %s from %s cache", TLScontext->namaddr, 234 STR(cache_id), TLScontext->cache_type); 235 236 tls_mgr_delete(TLScontext->cache_type, STR(cache_id)); 237 vstring_free(cache_id); 238} 239 240/* new_server_session_cb - callback to save session to server cache */ 241 242static int new_server_session_cb(SSL *ssl, SSL_SESSION *session) 243{ 244 const char *myname = "new_server_session_cb"; 245 VSTRING *cache_id; 246 TLS_SESS_STATE *TLScontext; 247 VSTRING *session_data; 248 249 if ((TLScontext = SSL_get_ex_data(ssl, TLScontext_index)) == 0) 250 msg_panic("%s: null TLScontext in new session callback", myname); 251 252 GEN_CACHE_ID(cache_id, session->session_id, session->session_id_length, 253 TLScontext->serverid); 254 255 if (TLScontext->log_mask & TLS_LOG_CACHE) 256 msg_info("%s: save session %s to %s cache", TLScontext->namaddr, 257 STR(cache_id), TLScontext->cache_type); 258 259 /* 260 * Passivate and save the session state. 261 */ 262 session_data = tls_session_passivate(session); 263 if (session_data) 264 tls_mgr_update(TLScontext->cache_type, STR(cache_id), 265 STR(session_data), LEN(session_data)); 266 267 /* 268 * Clean up. 269 */ 270 if (session_data) 271 vstring_free(session_data); 272 vstring_free(cache_id); 273 SSL_SESSION_free(session); /* 200502 */ 274 275 return (1); 276} 277 278/* tls_server_init - initialize the server-side TLS engine */ 279 280TLS_APPL_STATE *tls_server_init(const TLS_SERVER_INIT_PROPS *props) 281{ 282 SSL_CTX *server_ctx; 283 long off = 0; 284 int verify_flags = SSL_VERIFY_NONE; 285 int cachable; 286 int protomask; 287 TLS_APPL_STATE *app_ctx; 288 const EVP_MD *md_alg; 289 unsigned int md_len; 290 int log_mask; 291 292 /* 293 * Convert user loglevel to internal logmask. 294 */ 295 log_mask = tls_log_mask(props->log_param, props->log_level); 296 297 if (log_mask & TLS_LOG_VERBOSE) 298 msg_info("initializing the server-side TLS engine"); 299 300 /* 301 * Load (mostly cipher related) TLS-library internal main.cf parameters. 302 */ 303 tls_param_init(); 304 305 /* 306 * Detect mismatch between compile-time headers and run-time library. 307 */ 308 tls_check_version(); 309 310 /* 311 * Initialize the OpenSSL library by the book! To start with, we must 312 * initialize the algorithms. We want cleartext error messages instead of 313 * just error codes, so we load the error_strings. 314 */ 315 SSL_load_error_strings(); 316 OpenSSL_add_ssl_algorithms(); 317 318 /* 319 * First validate the protocols. If these are invalid, we can't continue. 320 */ 321 protomask = tls_protocol_mask(props->protocols); 322 if (protomask == TLS_PROTOCOL_INVALID) { 323 /* tls_protocol_mask() logs no warning. */ 324 msg_warn("Invalid TLS protocol list \"%s\": disabling TLS support", 325 props->protocols); 326 return (0); 327 } 328 329 /* 330 * Create an application data index for SSL objects, so that we can 331 * attach TLScontext information; this information is needed inside 332 * tls_verify_certificate_callback(). 333 */ 334 if (TLScontext_index < 0) { 335 if ((TLScontext_index = SSL_get_ex_new_index(0, 0, 0, 0, 0)) < 0) { 336 msg_warn("Cannot allocate SSL application data index: " 337 "disabling TLS support"); 338 return (0); 339 } 340 } 341 342 /* 343 * If the administrator specifies an unsupported digest algorithm, fail 344 * now, rather than in the middle of a TLS handshake. 345 */ 346 if ((md_alg = EVP_get_digestbyname(props->fpt_dgst)) == 0) { 347 msg_warn("Digest algorithm \"%s\" not found: disabling TLS support", 348 props->fpt_dgst); 349 return (0); 350 } 351 352 /* 353 * Sanity check: Newer shared libraries may use larger digests. 354 */ 355 if ((md_len = EVP_MD_size(md_alg)) > EVP_MAX_MD_SIZE) { 356 msg_warn("Digest algorithm \"%s\" output size %u too large:" 357 " disabling TLS support", props->fpt_dgst, md_len); 358 return (0); 359 } 360 361 /* 362 * Initialize the PRNG (Pseudo Random Number Generator) with some seed 363 * from external and internal sources. Don't enable TLS without some real 364 * entropy. 365 */ 366 if (tls_ext_seed(var_tls_daemon_rand_bytes) < 0) { 367 msg_warn("no entropy for TLS key generation: disabling TLS support"); 368 return (0); 369 } 370 tls_int_seed(); 371 372 /* 373 * The SSL/TLS specifications require the client to send a message in the 374 * oldest specification it understands with the highest level it 375 * understands in the message. Netscape communicator can still 376 * communicate with SSLv2 servers, so it sends out a SSLv2 client hello. 377 * To deal with it, our server must be SSLv2 aware (even if we don't like 378 * SSLv2), so we need to have the SSLv23 server here. If we want to limit 379 * the protocol level, we can add an option to not use SSLv2/v3/TLSv1 380 * later. 381 */ 382 ERR_clear_error(); 383 if ((server_ctx = SSL_CTX_new(SSLv23_server_method())) == 0) { 384 msg_warn("cannot allocate server SSL_CTX: disabling TLS support"); 385 tls_print_errors(); 386 return (0); 387 } 388 389 /* 390 * See the verify callback in tls_verify.c 391 */ 392 SSL_CTX_set_verify_depth(server_ctx, props->verifydepth + 1); 393 394 /* 395 * Protocol work-arounds, OpenSSL version dependent. 396 */ 397 off |= tls_bug_bits(); 398 SSL_CTX_set_options(server_ctx, off); 399 400 /* 401 * Global protocol selection. 402 */ 403 if (protomask != 0) 404 SSL_CTX_set_options(server_ctx, 405 ((protomask & TLS_PROTOCOL_TLSv1) ? SSL_OP_NO_TLSv1 : 0L) 406#ifdef SSL_OP_NO_TLSv1_1 407 | ((protomask & TLS_PROTOCOL_TLSv1_1) ? SSL_OP_NO_TLSv1_1 : 0L) 408#endif 409#ifdef SSL_OP_NO_TLSv1_2 410 | ((protomask & TLS_PROTOCOL_TLSv1_2) ? SSL_OP_NO_TLSv1_2 : 0L) 411#endif 412 | ((protomask & TLS_PROTOCOL_SSLv3) ? SSL_OP_NO_SSLv3 : 0L) 413 | ((protomask & TLS_PROTOCOL_SSLv2) ? SSL_OP_NO_SSLv2 : 0L)); 414 415#if OPENSSL_VERSION_NUMBER >= 0x0090700fL 416 417 /* 418 * Some sites may want to give the client less rope. On the other hand, 419 * this could trigger inter-operability issues, the client should not 420 * offer ciphers it implements poorly, but this hasn't stopped some 421 * vendors from getting it wrong. 422 * 423 * XXX: Given OpenSSL's security history, nobody should still be using 424 * 0.9.7, let alone 0.9.6 or earlier. Warning added to TLS_README.html. 425 */ 426 if (var_tls_preempt_clist) 427 SSL_CTX_set_options(server_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE); 428#endif 429 430 /* 431 * Set the call-back routine to debug handshake progress. 432 */ 433 if (log_mask & TLS_LOG_DEBUG) 434 SSL_CTX_set_info_callback(server_ctx, tls_info_callback); 435 436 /* 437 * Load the CA public key certificates for both the server cert and for 438 * the verification of client certificates. As provided by OpenSSL we 439 * support two types of CA certificate handling: One possibility is to 440 * add all CA certificates to one large CAfile, the other possibility is 441 * a directory pointed to by CApath, containing separate files for each 442 * CA with softlinks named after the hash values of the certificate. The 443 * first alternative has the advantage that the file is opened and read 444 * at startup time, so that you don't have the hassle to maintain another 445 * copy of the CApath directory for chroot-jail. 446 */ 447 if (tls_set_ca_certificate_info(server_ctx, 448 props->CAfile, props->CApath) < 0) { 449 /* tls_set_ca_certificate_info() already logs a warning. */ 450 SSL_CTX_free(server_ctx); /* 200411 */ 451 return (0); 452 } 453 454 /* 455 * Load the server public key certificate and private key from file and 456 * check whether the cert matches the key. We can use RSA certificates 457 * ("cert") DSA certificates ("dcert") or ECDSA certificates ("eccert"). 458 * All three can be made available at the same time. The CA certificates 459 * for all three are handled in the same setup already finished. Which 460 * one is used depends on the cipher negotiated (that is: the first 461 * cipher listed by the client which does match the server). A client 462 * with RSA only (e.g. Netscape) will use the RSA certificate only. A 463 * client with openssl-library will use RSA first if not especially 464 * changed in the cipher setup. 465 */ 466 if (tls_set_my_certificate_key_info(server_ctx, 467 props->cert_file, 468 props->key_file, 469 props->dcert_file, 470 props->dkey_file, 471 props->eccert_file, 472 props->eckey_file) < 0) { 473 /* tls_set_my_certificate_key_info() already logs a warning. */ 474 SSL_CTX_free(server_ctx); /* 200411 */ 475 return (0); 476 } 477 478 /* 479 * According to OpenSSL documentation, a temporary RSA key is needed when 480 * export ciphers are in use, because the certified key cannot be 481 * directly used. 482 */ 483 SSL_CTX_set_tmp_rsa_callback(server_ctx, tls_tmp_rsa_cb); 484 485 /* 486 * Diffie-Hellman key generation parameters can either be loaded from 487 * files (preferred) or taken from compiled in values. First, set the 488 * callback that will select the values when requested, then load the 489 * (possibly) available DH parameters from files. We are generous with 490 * the error handling, since we do have default values compiled in, so we 491 * will not abort but just log the error message. 492 */ 493 SSL_CTX_set_tmp_dh_callback(server_ctx, tls_tmp_dh_cb); 494 if (*props->dh1024_param_file != 0) 495 tls_set_dh_from_file(props->dh1024_param_file, 1024); 496 if (*props->dh512_param_file != 0) 497 tls_set_dh_from_file(props->dh512_param_file, 512); 498 499 /* 500 * Enable EECDH if available, errors are not fatal, we just keep going 501 * with any remaining key-exchange algorithms. 502 */ 503 (void) tls_set_eecdh_curve(server_ctx, props->eecdh_grade); 504 505 /* 506 * If we want to check client certificates, we have to indicate it in 507 * advance. By now we only allow to decide on a global basis. If we want 508 * to allow certificate based relaying, we must ask the client to provide 509 * one with SSL_VERIFY_PEER. The client now can decide, whether it 510 * provides one or not. We can enforce a failure of the negotiation with 511 * SSL_VERIFY_FAIL_IF_NO_PEER_CERT, if we do not allow a connection 512 * without one. In the "server hello" following the initialization by the 513 * "client hello" the server must provide a list of CAs it is willing to 514 * accept. Some clever clients will then select one from the list of 515 * available certificates matching these CAs. Netscape Communicator will 516 * present the list of certificates for selecting the one to be sent, or 517 * it will issue a warning, if there is no certificate matching the 518 * available CAs. 519 * 520 * With regard to the purpose of the certificate for relaying, we might like 521 * a later negotiation, maybe relaying would already be allowed for other 522 * reasons, but this would involve severe changes in the internal postfix 523 * logic, so we have to live with it the way it is. 524 */ 525 if (props->ask_ccert) 526 verify_flags = SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE; 527 SSL_CTX_set_verify(server_ctx, verify_flags, 528 tls_verify_certificate_callback); 529 if (*props->CAfile) 530 SSL_CTX_set_client_CA_list(server_ctx, 531 SSL_load_client_CA_file(props->CAfile)); 532 533 /* 534 * Initialize our own TLS server handle, before diving into the details 535 * of TLS session cache management. 536 */ 537 app_ctx = tls_alloc_app_context(server_ctx, log_mask); 538 539 /* 540 * The session cache is implemented by the tlsmgr(8) server. 541 * 542 * XXX 200502 Surprise: when OpenSSL purges an entry from the in-memory 543 * cache, it also attempts to purge the entry from the on-disk cache. 544 * This is undesirable, especially when we set the in-memory cache size 545 * to 1. For this reason we don't allow OpenSSL to purge on-disk cache 546 * entries, and leave it up to the tlsmgr process instead. Found by 547 * Victor Duchovni. 548 */ 549 550 if (tls_mgr_policy(props->cache_type, &cachable) != TLS_MGR_STAT_OK) 551 cachable = 0; 552 553 if (cachable || props->set_sessid) { 554 555 /* 556 * Initialize the session cache. 557 * 558 * With a large number of concurrent smtpd(8) processes, it is not a 559 * good idea to cache multiple large session objects in each process. 560 * We set the internal cache size to 1, and don't register a 561 * "remove_cb" so as to avoid deleting good sessions from the 562 * external cache prematurely (when the internal cache is full, 563 * OpenSSL removes sessions from the external cache also)! 564 * 565 * This makes SSL_CTX_remove_session() not useful for flushing broken 566 * sessions from the external cache, so we must delete them directly 567 * (not via a callback). 568 * 569 * Set a session id context to identify to what type of server process 570 * created a session. In our case, the context is simply the name of 571 * the mail system: "Postfix/TLS". 572 */ 573 SSL_CTX_sess_set_cache_size(server_ctx, 1); 574 SSL_CTX_set_session_id_context(server_ctx, 575 (void *) &server_session_id_context, 576 sizeof(server_session_id_context)); 577 SSL_CTX_set_session_cache_mode(server_ctx, 578 SSL_SESS_CACHE_SERVER | 579 SSL_SESS_CACHE_NO_AUTO_CLEAR); 580 if (cachable) { 581 app_ctx->cache_type = mystrdup(props->cache_type); 582 583 SSL_CTX_sess_set_get_cb(server_ctx, get_server_session_cb); 584 SSL_CTX_sess_set_new_cb(server_ctx, new_server_session_cb); 585 } 586 587 /* 588 * OpenSSL ignores timed-out sessions. We need to set the internal 589 * cache timeout at least as high as the external cache timeout. This 590 * applies even if no internal cache is used. 591 */ 592 SSL_CTX_set_timeout(server_ctx, props->scache_timeout); 593 } else { 594 595 /* 596 * If we have no external cache, disable all caching. No use wasting 597 * server memory resources with sessions they are unlikely to be able 598 * to reuse. 599 */ 600 SSL_CTX_set_session_cache_mode(server_ctx, SSL_SESS_CACHE_OFF); 601 } 602 603 return (app_ctx); 604} 605 606 /* 607 * This is the actual startup routine for a new connection. We expect that 608 * the SMTP buffers are flushed and the "220 Ready to start TLS" was sent to 609 * the client, so that we can immediately start the TLS handshake process. 610 */ 611TLS_SESS_STATE *tls_server_start(const TLS_SERVER_START_PROPS *props) 612{ 613 int sts; 614 TLS_SESS_STATE *TLScontext; 615 const char *cipher_list; 616 TLS_APPL_STATE *app_ctx = props->ctx; 617 int log_mask = app_ctx->log_mask; 618 619 /* 620 * Implicitly enable logging of trust chain errors when verified certs 621 * are required. 622 */ 623 if (props->requirecert) 624 log_mask |= TLS_LOG_UNTRUSTED; 625 626 if (log_mask & TLS_LOG_VERBOSE) 627 msg_info("setting up TLS connection from %s", props->namaddr); 628 629 cipher_list = tls_set_ciphers(app_ctx, "TLS", props->cipher_grade, 630 props->cipher_exclusions); 631 if (cipher_list == 0) { 632 msg_warn("%s: %s: aborting TLS session", props->namaddr, 633 vstring_str(app_ctx->why)); 634 return (0); 635 } 636 if (log_mask & TLS_LOG_VERBOSE) 637 msg_info("%s: TLS cipher list \"%s\"", props->namaddr, cipher_list); 638 639 /* 640 * Allocate a new TLScontext for the new connection and get an SSL 641 * structure. Add the location of TLScontext to the SSL to later retrieve 642 * the information inside the tls_verify_certificate_callback(). 643 */ 644 TLScontext = tls_alloc_sess_context(log_mask, props->namaddr); 645 TLScontext->cache_type = app_ctx->cache_type; 646 647 TLScontext->serverid = mystrdup(props->serverid); 648 TLScontext->am_server = 1; 649 650 TLScontext->fpt_dgst = mystrdup(props->fpt_dgst); 651 TLScontext->stream = props->stream; 652 653 ERR_clear_error(); 654 if ((TLScontext->con = (SSL *) SSL_new(app_ctx->ssl_ctx)) == 0) { 655 msg_warn("Could not allocate 'TLScontext->con' with SSL_new()"); 656 tls_print_errors(); 657 tls_free_context(TLScontext); 658 return (0); 659 } 660 if (!SSL_set_ex_data(TLScontext->con, TLScontext_index, TLScontext)) { 661 msg_warn("Could not set application data for 'TLScontext->con'"); 662 tls_print_errors(); 663 tls_free_context(TLScontext); 664 return (0); 665 } 666 667 /* 668 * Before really starting anything, try to seed the PRNG a little bit 669 * more. 670 */ 671 tls_int_seed(); 672 (void) tls_ext_seed(var_tls_daemon_rand_bytes); 673 674 /* 675 * Initialize the SSL connection to accept state. This should not be 676 * necessary anymore since 0.9.3, but the call is still in the library 677 * and maintaining compatibility never hurts. 678 */ 679 SSL_set_accept_state(TLScontext->con); 680 681 /* 682 * Connect the SSL connection with the network socket. 683 */ 684 if (SSL_set_fd(TLScontext->con, props->stream == 0 ? props->fd : 685 vstream_fileno(props->stream)) != 1) { 686 msg_info("SSL_set_fd error to %s", props->namaddr); 687 tls_print_errors(); 688 uncache_session(app_ctx->ssl_ctx, TLScontext); 689 tls_free_context(TLScontext); 690 return (0); 691 } 692 693 /* 694 * If the debug level selected is high enough, all of the data is dumped: 695 * TLS_LOG_TLSPKTS will dump the SSL negotiation, TLS_LOG_ALLPKTS will 696 * dump everything. 697 * 698 * We do have an SSL_set_fd() and now suddenly a BIO_ routine is called? 699 * Well there is a BIO below the SSL routines that is automatically 700 * created for us, so we can use it for debugging purposes. 701 */ 702 if (log_mask & TLS_LOG_TLSPKTS) 703 BIO_set_callback(SSL_get_rbio(TLScontext->con), tls_bio_dump_cb); 704 705 /* 706 * If we don't trigger the handshake in the library, leave control over 707 * SSL_accept/read/write/etc with the application. 708 */ 709 if (props->stream == 0) 710 return (TLScontext); 711 712 /* 713 * Turn on non-blocking I/O so that we can enforce timeouts on network 714 * I/O. 715 */ 716 non_blocking(vstream_fileno(props->stream), NON_BLOCKING); 717 718 /* 719 * Start TLS negotiations. This process is a black box that invokes our 720 * call-backs for session caching and certificate verification. 721 * 722 * Error handling: If the SSL handhake fails, we print out an error message 723 * and remove all TLS state concerning this session. 724 */ 725 sts = tls_bio_accept(vstream_fileno(props->stream), props->timeout, 726 TLScontext); 727 if (sts <= 0) { 728 if (ERR_peek_error() != 0) { 729 msg_info("SSL_accept error from %s: %d", props->namaddr, sts); 730 tls_print_errors(); 731 } else if (errno != 0) { 732 msg_info("SSL_accept error from %s: %m", props->namaddr); 733 } else { 734 msg_info("SSL_accept error from %s: lost connection", 735 props->namaddr); 736 } 737 tls_free_context(TLScontext); 738 return (0); 739 } 740 return (tls_server_post_accept(TLScontext)); 741} 742 743/* tls_server_post_accept - post-handshake processing */ 744 745TLS_SESS_STATE *tls_server_post_accept(TLS_SESS_STATE *TLScontext) 746{ 747 const SSL_CIPHER *cipher; 748 X509 *peer; 749 char buf[CCERT_BUFSIZ]; 750 751 /* Turn off packet dump if only dumping the handshake */ 752 if ((TLScontext->log_mask & TLS_LOG_ALLPKTS) == 0) 753 BIO_set_callback(SSL_get_rbio(TLScontext->con), 0); 754 755 /* 756 * The caller may want to know if this session was reused or if a new 757 * session was negotiated. 758 */ 759 TLScontext->session_reused = SSL_session_reused(TLScontext->con); 760 if ((TLScontext->log_mask & TLS_LOG_CACHE) && TLScontext->session_reused) 761 msg_info("%s: Reusing old session", TLScontext->namaddr); 762 763 /* 764 * Let's see whether a peer certificate is available and what is the 765 * actual information. We want to save it for later use. 766 */ 767 peer = SSL_get_peer_certificate(TLScontext->con); 768 if (peer != NULL) { 769 TLScontext->peer_status |= TLS_CERT_FLAG_PRESENT; 770 if (SSL_get_verify_result(TLScontext->con) == X509_V_OK) 771 TLScontext->peer_status |= TLS_CERT_FLAG_TRUSTED; 772 773 if (TLScontext->log_mask & TLS_LOG_VERBOSE) { 774 X509_NAME_oneline(X509_get_subject_name(peer), 775 buf, sizeof(buf)); 776 msg_info("subject=%s", buf); 777 X509_NAME_oneline(X509_get_issuer_name(peer), 778 buf, sizeof(buf)); 779 msg_info("issuer=%s", buf); 780 } 781 TLScontext->peer_CN = tls_peer_CN(peer, TLScontext); 782 TLScontext->issuer_CN = tls_issuer_CN(peer, TLScontext); 783 TLScontext->peer_fingerprint = 784 tls_fingerprint(peer, TLScontext->fpt_dgst); 785 TLScontext->peer_pkey_fprint = 786 tls_pkey_fprint(peer, TLScontext->fpt_dgst); 787 788 if (TLScontext->log_mask & (TLS_LOG_VERBOSE | TLS_LOG_PEERCERT)) { 789 msg_info("%s: subject_CN=%s, issuer=%s, fingerprint=%s" 790 ", pkey_fingerprint=%s", 791 TLScontext->namaddr, 792 TLScontext->peer_CN, TLScontext->issuer_CN, 793 TLScontext->peer_fingerprint, 794 TLScontext->peer_pkey_fprint); 795 } 796 X509_free(peer); 797 } else { 798 TLScontext->peer_CN = mystrdup(""); 799 TLScontext->issuer_CN = mystrdup(""); 800 TLScontext->peer_fingerprint = mystrdup(""); 801 } 802 803 /* 804 * Finally, collect information about protocol and cipher for logging 805 */ 806 TLScontext->protocol = SSL_get_version(TLScontext->con); 807 cipher = SSL_get_current_cipher(TLScontext->con); 808 TLScontext->cipher_name = SSL_CIPHER_get_name(cipher); 809 TLScontext->cipher_usebits = SSL_CIPHER_get_bits(cipher, 810 &(TLScontext->cipher_algbits)); 811 812 /* 813 * If the library triggered the SSL handshake, switch to the 814 * tls_timed_read/write() functions and make the TLScontext available to 815 * those functions. Otherwise, leave control over SSL_read/write/etc. 816 * with the application. 817 */ 818 if (TLScontext->stream != 0) 819 tls_stream_start(TLScontext->stream, TLScontext); 820 821 /* 822 * All the key facts in a single log entry. 823 */ 824 if (TLScontext->log_mask & TLS_LOG_SUMMARY) 825 msg_info("%s TLS connection established from %s: %s with cipher %s " 826 "(%d/%d bits)", !TLS_CERT_IS_PRESENT(TLScontext) ? "Anonymous" 827 : TLS_CERT_IS_TRUSTED(TLScontext) ? "Trusted" : "Untrusted", 828 TLScontext->namaddr, TLScontext->protocol, TLScontext->cipher_name, 829 TLScontext->cipher_usebits, TLScontext->cipher_algbits); 830 831 tls_int_seed(); 832 833 return (TLScontext); 834} 835 836#endif /* USE_TLS */ 837