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Do not permit multi-component wildcards on certificate names (OpenSSL, EXPERIMENTAL_C...
[exim.git] / src / src / tls-openssl.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Portions Copyright (c) The OpenSSL Project 1999 */
9
10 /* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
11 library. It is #included into the tls.c file when that library is used. The
12 code herein is based on a patch that was originally contributed by Steve
13 Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara.
14
15 No cryptographic code is included in Exim. All this module does is to call
16 functions from the OpenSSL library. */
17
18
19 /* Heading stuff */
20
21 #include <openssl/lhash.h>
22 #include <openssl/ssl.h>
23 #include <openssl/err.h>
24 #include <openssl/rand.h>
25 #ifndef DISABLE_OCSP
26 # include <openssl/ocsp.h>
27 #endif
28 #ifdef EXPERIMENTAL_DANE
29 # include <danessl.h>
30 #endif
31
32
33 #ifndef DISABLE_OCSP
34 # define EXIM_OCSP_SKEW_SECONDS (300L)
35 # define EXIM_OCSP_MAX_AGE (-1L)
36 #endif
37
38 #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
39 # define EXIM_HAVE_OPENSSL_TLSEXT
40 #endif
41 #if OPENSSL_VERSION_NUMBER >= 0x010100000L
42 # define EXIM_HAVE_OPENSSL_CHECKHOST
43 #endif
44 #if OPENSSL_VERSION_NUMBER >= 0x010000000L \
45 && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L
46 # define EXIM_HAVE_OPENSSL_CHECKHOST
47 #endif
48
49 #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP)
50 # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile"
51 # define DISABLE_OCSP
52 #endif
53
54 /* Structure for collecting random data for seeding. */
55
56 typedef struct randstuff {
57 struct timeval tv;
58 pid_t p;
59 } randstuff;
60
61 /* Local static variables */
62
63 static BOOL client_verify_callback_called = FALSE;
64 static BOOL server_verify_callback_called = FALSE;
65 static const uschar *sid_ctx = US"exim";
66
67 /* We have three different contexts to care about.
68
69 Simple case: client, `client_ctx`
70 As a client, we can be doing a callout or cut-through delivery while receiving
71 a message. So we have a client context, which should have options initialised
72 from the SMTP Transport.
73
74 Server:
75 There are two cases: with and without ServerNameIndication from the client.
76 Given TLS SNI, we can be using different keys, certs and various other
77 configuration settings, because they're re-expanded with $tls_sni set. This
78 allows vhosting with TLS. This SNI is sent in the handshake.
79 A client might not send SNI, so we need a fallback, and an initial setup too.
80 So as a server, we start out using `server_ctx`.
81 If SNI is sent by the client, then we as server, mid-negotiation, try to clone
82 `server_sni` from `server_ctx` and then initialise settings by re-expanding
83 configuration.
84 */
85
86 static SSL_CTX *client_ctx = NULL;
87 static SSL_CTX *server_ctx = NULL;
88 static SSL *client_ssl = NULL;
89 static SSL *server_ssl = NULL;
90
91 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
92 static SSL_CTX *server_sni = NULL;
93 #endif
94
95 static char ssl_errstring[256];
96
97 static int ssl_session_timeout = 200;
98 static BOOL client_verify_optional = FALSE;
99 static BOOL server_verify_optional = FALSE;
100
101 static BOOL reexpand_tls_files_for_sni = FALSE;
102
103
104 typedef struct tls_ext_ctx_cb {
105 uschar *certificate;
106 uschar *privatekey;
107 #ifndef DISABLE_OCSP
108 BOOL is_server;
109 union {
110 struct {
111 uschar *file;
112 uschar *file_expanded;
113 OCSP_RESPONSE *response;
114 } server;
115 struct {
116 X509_STORE *verify_store; /* non-null if status requested */
117 BOOL verify_required;
118 } client;
119 } u_ocsp;
120 #endif
121 uschar *dhparam;
122 /* these are cached from first expand */
123 uschar *server_cipher_list;
124 /* only passed down to tls_error: */
125 host_item *host;
126
127 #ifdef EXPERIMENTAL_CERTNAMES
128 uschar * verify_cert_hostnames;
129 #endif
130 #ifdef EXPERIMENTAL_EVENT
131 uschar * event_action;
132 #endif
133 } tls_ext_ctx_cb;
134
135 /* should figure out a cleanup of API to handle state preserved per
136 implementation, for various reasons, which can be void * in the APIs.
137 For now, we hack around it. */
138 tls_ext_ctx_cb *client_static_cbinfo = NULL;
139 tls_ext_ctx_cb *server_static_cbinfo = NULL;
140
141 static int
142 setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
143 int (*cert_vfy_cb)(int, X509_STORE_CTX *) );
144
145 /* Callbacks */
146 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
147 static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg);
148 #endif
149 #ifndef DISABLE_OCSP
150 static int tls_server_stapling_cb(SSL *s, void *arg);
151 #endif
152
153
154 /*************************************************
155 * Handle TLS error *
156 *************************************************/
157
158 /* Called from lots of places when errors occur before actually starting to do
159 the TLS handshake, that is, while the session is still in clear. Always returns
160 DEFER for a server and FAIL for a client so that most calls can use "return
161 tls_error(...)" to do this processing and then give an appropriate return. A
162 single function is used for both server and client, because it is called from
163 some shared functions.
164
165 Argument:
166 prefix text to include in the logged error
167 host NULL if setting up a server;
168 the connected host if setting up a client
169 msg error message or NULL if we should ask OpenSSL
170
171 Returns: OK/DEFER/FAIL
172 */
173
174 static int
175 tls_error(uschar *prefix, host_item *host, uschar *msg)
176 {
177 if (!msg)
178 {
179 ERR_error_string(ERR_get_error(), ssl_errstring);
180 msg = (uschar *)ssl_errstring;
181 }
182
183 if (host)
184 {
185 log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s): %s",
186 host->name, host->address, prefix, msg);
187 return FAIL;
188 }
189 else
190 {
191 uschar *conn_info = smtp_get_connection_info();
192 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0)
193 conn_info += 5;
194 /* I'd like to get separated H= here, but too hard for now */
195 log_write(0, LOG_MAIN, "TLS error on %s (%s): %s",
196 conn_info, prefix, msg);
197 return DEFER;
198 }
199 }
200
201
202
203 /*************************************************
204 * Callback to generate RSA key *
205 *************************************************/
206
207 /*
208 Arguments:
209 s SSL connection
210 export not used
211 keylength keylength
212
213 Returns: pointer to generated key
214 */
215
216 static RSA *
217 rsa_callback(SSL *s, int export, int keylength)
218 {
219 RSA *rsa_key;
220 export = export; /* Shut picky compilers up */
221 DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength);
222 rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL);
223 if (rsa_key == NULL)
224 {
225 ERR_error_string(ERR_get_error(), ssl_errstring);
226 log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s",
227 ssl_errstring);
228 return NULL;
229 }
230 return rsa_key;
231 }
232
233
234
235 /* Extreme debug
236 #ifndef DISABLE_OCSP
237 void
238 x509_store_dump_cert_s_names(X509_STORE * store)
239 {
240 STACK_OF(X509_OBJECT) * roots= store->objs;
241 int i;
242 static uschar name[256];
243
244 for(i= 0; i<sk_X509_OBJECT_num(roots); i++)
245 {
246 X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i);
247 if(tmp_obj->type == X509_LU_X509)
248 {
249 X509 * current_cert= tmp_obj->data.x509;
250 X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name));
251 debug_printf(" %s\n", name);
252 }
253 }
254 }
255 #endif
256 */
257
258
259 /*************************************************
260 * Callback for verification *
261 *************************************************/
262
263 /* The SSL library does certificate verification if set up to do so. This
264 callback has the current yes/no state is in "state". If verification succeeded,
265 we set up the tls_peerdn string. If verification failed, what happens depends
266 on whether the client is required to present a verifiable certificate or not.
267
268 If verification is optional, we change the state to yes, but still log the
269 verification error. For some reason (it really would help to have proper
270 documentation of OpenSSL), this callback function then gets called again, this
271 time with state = 1. In fact, that's useful, because we can set up the peerdn
272 value, but we must take care not to set the private verified flag on the second
273 time through.
274
275 Note: this function is not called if the client fails to present a certificate
276 when asked. We get here only if a certificate has been received. Handling of
277 optional verification for this case is done when requesting SSL to verify, by
278 setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case.
279
280 May be called multiple times for different issues with a certificate, even
281 for a given "depth" in the certificate chain.
282
283 Arguments:
284 state current yes/no state as 1/0
285 x509ctx certificate information.
286 client TRUE for client startup, FALSE for server startup
287
288 Returns: 1 if verified, 0 if not
289 */
290
291 static int
292 verify_callback(int state, X509_STORE_CTX *x509ctx,
293 tls_support *tlsp, BOOL *calledp, BOOL *optionalp)
294 {
295 X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
296 int depth = X509_STORE_CTX_get_error_depth(x509ctx);
297 static uschar txt[256];
298 #ifdef EXPERIMENTAL_EVENT
299 uschar * ev;
300 uschar * yield;
301 #endif
302
303 X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt));
304
305 if (state == 0)
306 {
307 log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s",
308 depth,
309 X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)),
310 txt);
311 *calledp = TRUE;
312 if (!*optionalp)
313 {
314 tlsp->peercert = X509_dup(cert);
315 return 0; /* reject */
316 }
317 DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
318 "tls_try_verify_hosts)\n");
319 }
320
321 else if (depth != 0)
322 {
323 DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, txt);
324 #ifndef DISABLE_OCSP
325 if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store)
326 { /* client, wanting stapling */
327 /* Add the server cert's signing chain as the one
328 for the verification of the OCSP stapled information. */
329
330 if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store,
331 cert))
332 ERR_clear_error();
333 }
334 #endif
335 #ifdef EXPERIMENTAL_EVENT
336 ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
337 if (ev)
338 {
339 tlsp->peercert = X509_dup(cert);
340 if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth))))
341 {
342 log_write(0, LOG_MAIN, "SSL verify denied by event-action: "
343 "depth=%d cert=%s: %s", depth, txt, yield);
344 *calledp = TRUE;
345 if (!*optionalp)
346 return 0; /* reject */
347 DEBUG(D_tls) debug_printf("Event-action verify failure overridden "
348 "(host in tls_try_verify_hosts)\n");
349 }
350 X509_free(tlsp->peercert);
351 tlsp->peercert = NULL;
352 }
353 #endif
354 }
355 else
356 {
357 #ifdef EXPERIMENTAL_CERTNAMES
358 uschar * verify_cert_hostnames;
359 #endif
360
361 tlsp->peerdn = txt;
362 tlsp->peercert = X509_dup(cert);
363
364 #ifdef EXPERIMENTAL_CERTNAMES
365 if ( tlsp == &tls_out
366 && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames)))
367 /* client, wanting hostname check */
368
369 # if EXIM_HAVE_OPENSSL_CHECKHOST
370 # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
371 # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0
372 # endif
373 # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
374 # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0
375 # endif
376 {
377 int sep = 0;
378 uschar * list = verify_cert_hostnames;
379 uschar * name;
380 int rc;
381 while ((name = string_nextinlist(&list, &sep, NULL, 0)))
382 if ((rc = X509_check_host(cert, name, 0,
383 X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
384 | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS)))
385 {
386 if (rc < 0)
387 {
388 log_write(0, LOG_MAIN, "SSL verify error: internal error\n");
389 name = NULL;
390 }
391 break;
392 }
393 if (!name)
394 {
395 log_write(0, LOG_MAIN,
396 "SSL verify error: certificate name mismatch: \"%s\"\n", txt);
397 *calledp = TRUE;
398 if (!*optionalp)
399 return 0; /* reject */
400 DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
401 "tls_try_verify_hosts)\n");
402 }
403 }
404 # else
405 if (!tls_is_name_for_cert(verify_cert_hostnames, cert))
406 {
407 log_write(0, LOG_MAIN,
408 "SSL verify error: certificate name mismatch: \"%s\"\n", txt);
409 *calledp = TRUE;
410 if (!*optionalp)
411 return 0; /* reject */
412 DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
413 "tls_try_verify_hosts)\n");
414 }
415 # endif
416 #endif /*EXPERIMENTAL_CERTNAMES*/
417
418 #ifdef EXPERIMENTAL_EVENT
419 ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
420 if (ev)
421 if ((yield = event_raise(ev, US"tls:cert", US"0")))
422 {
423 log_write(0, LOG_MAIN, "SSL verify denied by event-action: "
424 "depth=0 cert=%s: %s", txt, yield);
425 *calledp = TRUE;
426 if (!*optionalp)
427 return 0; /* reject */
428 DEBUG(D_tls) debug_printf("Event-action verify failure overridden "
429 "(host in tls_try_verify_hosts)\n");
430 }
431 #endif
432
433 DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n",
434 *calledp ? "" : " authenticated", txt);
435 if (!*calledp) tlsp->certificate_verified = TRUE;
436 *calledp = TRUE;
437 }
438
439 return 1; /* accept, at least for this level */
440 }
441
442 static int
443 verify_callback_client(int state, X509_STORE_CTX *x509ctx)
444 {
445 return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional);
446 }
447
448 static int
449 verify_callback_server(int state, X509_STORE_CTX *x509ctx)
450 {
451 return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional);
452 }
453
454
455 #ifdef EXPERIMENTAL_DANE
456
457 /* This gets called *by* the dane library verify callback, which interposes
458 itself.
459 */
460 static int
461 verify_callback_client_dane(int state, X509_STORE_CTX * x509ctx)
462 {
463 X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
464 static uschar txt[256];
465 #ifdef EXPERIMENTAL_EVENT
466 int depth = X509_STORE_CTX_get_error_depth(x509ctx);
467 uschar * yield;
468 #endif
469
470 X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt));
471
472 DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", txt);
473 tls_out.peerdn = txt;
474 tls_out.peercert = X509_dup(cert);
475
476 #ifdef EXPERIMENTAL_EVENT
477 if (client_static_cbinfo->event_action)
478 {
479 if ((yield = event_raise(client_static_cbinfo->event_action,
480 US"tls:cert", string_sprintf("%d", depth))))
481 {
482 log_write(0, LOG_MAIN, "DANE verify denied by event-action: "
483 "depth=%d cert=%s: %s", depth, txt, yield);
484 tls_out.certificate_verified = FALSE;
485 return 0; /* reject */
486 }
487 if (depth != 0)
488 {
489 X509_free(tls_out.peercert);
490 tls_out.peercert = NULL;
491 }
492 }
493 #endif
494
495 if (state == 1)
496 tls_out.dane_verified =
497 tls_out.certificate_verified = TRUE;
498 return 1;
499 }
500
501 #endif /*EXPERIMENTAL_DANE*/
502
503
504 /*************************************************
505 * Information callback *
506 *************************************************/
507
508 /* The SSL library functions call this from time to time to indicate what they
509 are doing. We copy the string to the debugging output when TLS debugging has
510 been requested.
511
512 Arguments:
513 s the SSL connection
514 where
515 ret
516
517 Returns: nothing
518 */
519
520 static void
521 info_callback(SSL *s, int where, int ret)
522 {
523 where = where;
524 ret = ret;
525 DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s));
526 }
527
528
529
530 /*************************************************
531 * Initialize for DH *
532 *************************************************/
533
534 /* If dhparam is set, expand it, and load up the parameters for DH encryption.
535
536 Arguments:
537 dhparam DH parameter file or fixed parameter identity string
538 host connected host, if client; NULL if server
539
540 Returns: TRUE if OK (nothing to set up, or setup worked)
541 */
542
543 static BOOL
544 init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host)
545 {
546 BIO *bio;
547 DH *dh;
548 uschar *dhexpanded;
549 const char *pem;
550
551 if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded))
552 return FALSE;
553
554 if (!dhexpanded || !*dhexpanded)
555 bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1);
556 else if (dhexpanded[0] == '/')
557 {
558 if (!(bio = BIO_new_file(CS dhexpanded, "r")))
559 {
560 tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
561 host, US strerror(errno));
562 return FALSE;
563 }
564 }
565 else
566 {
567 if (Ustrcmp(dhexpanded, "none") == 0)
568 {
569 DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
570 return TRUE;
571 }
572
573 if (!(pem = std_dh_prime_named(dhexpanded)))
574 {
575 tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded),
576 host, US strerror(errno));
577 return FALSE;
578 }
579 bio = BIO_new_mem_buf(CS pem, -1);
580 }
581
582 if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)))
583 {
584 BIO_free(bio);
585 tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded),
586 host, NULL);
587 return FALSE;
588 }
589
590 /* Even if it is larger, we silently return success rather than cause things
591 * to fail out, so that a too-large DH will not knock out all TLS; it's a
592 * debatable choice. */
593 if ((8*DH_size(dh)) > tls_dh_max_bits)
594 {
595 DEBUG(D_tls)
596 debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d",
597 8*DH_size(dh), tls_dh_max_bits);
598 }
599 else
600 {
601 SSL_CTX_set_tmp_dh(sctx, dh);
602 DEBUG(D_tls)
603 debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n",
604 dhexpanded ? dhexpanded : US"default", 8*DH_size(dh));
605 }
606
607 DH_free(dh);
608 BIO_free(bio);
609
610 return TRUE;
611 }
612
613
614
615
616 #ifndef DISABLE_OCSP
617 /*************************************************
618 * Load OCSP information into state *
619 *************************************************/
620
621 /* Called to load the server OCSP response from the given file into memory, once
622 caller has determined this is needed. Checks validity. Debugs a message
623 if invalid.
624
625 ASSUMES: single response, for single cert.
626
627 Arguments:
628 sctx the SSL_CTX* to update
629 cbinfo various parts of session state
630 expanded the filename putatively holding an OCSP response
631
632 */
633
634 static void
635 ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded)
636 {
637 BIO *bio;
638 OCSP_RESPONSE *resp;
639 OCSP_BASICRESP *basic_response;
640 OCSP_SINGLERESP *single_response;
641 ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd;
642 X509_STORE *store;
643 unsigned long verify_flags;
644 int status, reason, i;
645
646 cbinfo->u_ocsp.server.file_expanded = string_copy(expanded);
647 if (cbinfo->u_ocsp.server.response)
648 {
649 OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response);
650 cbinfo->u_ocsp.server.response = NULL;
651 }
652
653 bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb");
654 if (!bio)
655 {
656 DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n",
657 cbinfo->u_ocsp.server.file_expanded);
658 return;
659 }
660
661 resp = d2i_OCSP_RESPONSE_bio(bio, NULL);
662 BIO_free(bio);
663 if (!resp)
664 {
665 DEBUG(D_tls) debug_printf("Error reading OCSP response.\n");
666 return;
667 }
668
669 status = OCSP_response_status(resp);
670 if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL)
671 {
672 DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n",
673 OCSP_response_status_str(status), status);
674 goto bad;
675 }
676
677 basic_response = OCSP_response_get1_basic(resp);
678 if (!basic_response)
679 {
680 DEBUG(D_tls)
681 debug_printf("OCSP response parse error: unable to extract basic response.\n");
682 goto bad;
683 }
684
685 store = SSL_CTX_get_cert_store(sctx);
686 verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */
687
688 /* May need to expose ability to adjust those flags?
689 OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT
690 OCSP_TRUSTOTHER OCSP_NOINTERN */
691
692 i = OCSP_basic_verify(basic_response, NULL, store, verify_flags);
693 if (i <= 0)
694 {
695 DEBUG(D_tls) {
696 ERR_error_string(ERR_get_error(), ssl_errstring);
697 debug_printf("OCSP response verify failure: %s\n", US ssl_errstring);
698 }
699 goto bad;
700 }
701
702 /* Here's the simplifying assumption: there's only one response, for the
703 one certificate we use, and nothing for anything else in a chain. If this
704 proves false, we need to extract a cert id from our issued cert
705 (tls_certificate) and use that for OCSP_resp_find_status() (which finds the
706 right cert in the stack and then calls OCSP_single_get0_status()).
707
708 I'm hoping to avoid reworking a bunch more of how we handle state here. */
709 single_response = OCSP_resp_get0(basic_response, 0);
710 if (!single_response)
711 {
712 DEBUG(D_tls)
713 debug_printf("Unable to get first response from OCSP basic response.\n");
714 goto bad;
715 }
716
717 status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd);
718 if (status != V_OCSP_CERTSTATUS_GOOD)
719 {
720 DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n",
721 OCSP_cert_status_str(status), status,
722 OCSP_crl_reason_str(reason), reason);
723 goto bad;
724 }
725
726 if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
727 {
728 DEBUG(D_tls) debug_printf("OCSP status invalid times.\n");
729 goto bad;
730 }
731
732 supply_response:
733 cbinfo->u_ocsp.server.response = resp;
734 return;
735
736 bad:
737 if (running_in_test_harness)
738 {
739 extern char ** environ;
740 uschar ** p;
741 for (p = USS environ; *p != NULL; p++)
742 if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
743 {
744 DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n");
745 goto supply_response;
746 }
747 }
748 return;
749 }
750 #endif /*!DISABLE_OCSP*/
751
752
753
754
755 /*************************************************
756 * Expand key and cert file specs *
757 *************************************************/
758
759 /* Called once during tls_init and possibly again during TLS setup, for a
760 new context, if Server Name Indication was used and tls_sni was seen in
761 the certificate string.
762
763 Arguments:
764 sctx the SSL_CTX* to update
765 cbinfo various parts of session state
766
767 Returns: OK/DEFER/FAIL
768 */
769
770 static int
771 tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo)
772 {
773 uschar *expanded;
774
775 if (cbinfo->certificate == NULL)
776 return OK;
777
778 if (Ustrstr(cbinfo->certificate, US"tls_sni") ||
779 Ustrstr(cbinfo->certificate, US"tls_in_sni") ||
780 Ustrstr(cbinfo->certificate, US"tls_out_sni")
781 )
782 reexpand_tls_files_for_sni = TRUE;
783
784 if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded))
785 return DEFER;
786
787 if (expanded != NULL)
788 {
789 DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded);
790 if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded))
791 return tls_error(string_sprintf(
792 "SSL_CTX_use_certificate_chain_file file=%s", expanded),
793 cbinfo->host, NULL);
794 }
795
796 if (cbinfo->privatekey != NULL &&
797 !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded))
798 return DEFER;
799
800 /* If expansion was forced to fail, key_expanded will be NULL. If the result
801 of the expansion is an empty string, ignore it also, and assume the private
802 key is in the same file as the certificate. */
803
804 if (expanded != NULL && *expanded != 0)
805 {
806 DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded);
807 if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM))
808 return tls_error(string_sprintf(
809 "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL);
810 }
811
812 #ifndef DISABLE_OCSP
813 if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL)
814 {
815 if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded))
816 return DEFER;
817
818 if (expanded != NULL && *expanded != 0)
819 {
820 DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded);
821 if (cbinfo->u_ocsp.server.file_expanded &&
822 (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0))
823 {
824 DEBUG(D_tls)
825 debug_printf("tls_ocsp_file value unchanged, using existing values.\n");
826 } else {
827 ocsp_load_response(sctx, cbinfo, expanded);
828 }
829 }
830 }
831 #endif
832
833 return OK;
834 }
835
836
837
838
839 /*************************************************
840 * Callback to handle SNI *
841 *************************************************/
842
843 /* Called when acting as server during the TLS session setup if a Server Name
844 Indication extension was sent by the client.
845
846 API documentation is OpenSSL s_server.c implementation.
847
848 Arguments:
849 s SSL* of the current session
850 ad unknown (part of OpenSSL API) (unused)
851 arg Callback of "our" registered data
852
853 Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK}
854 */
855
856 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
857 static int
858 tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg)
859 {
860 const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
861 tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
862 int rc;
863 int old_pool = store_pool;
864
865 if (!servername)
866 return SSL_TLSEXT_ERR_OK;
867
868 DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername,
869 reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)");
870
871 /* Make the extension value available for expansion */
872 store_pool = POOL_PERM;
873 tls_in.sni = string_copy(US servername);
874 store_pool = old_pool;
875
876 if (!reexpand_tls_files_for_sni)
877 return SSL_TLSEXT_ERR_OK;
878
879 /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually;
880 not confident that memcpy wouldn't break some internal reference counting.
881 Especially since there's a references struct member, which would be off. */
882
883 if (!(server_sni = SSL_CTX_new(SSLv23_server_method())))
884 {
885 ERR_error_string(ERR_get_error(), ssl_errstring);
886 DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring);
887 return SSL_TLSEXT_ERR_NOACK;
888 }
889
890 /* Not sure how many of these are actually needed, since SSL object
891 already exists. Might even need this selfsame callback, for reneg? */
892
893 SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx));
894 SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx));
895 SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx));
896 SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx));
897 SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
898 SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo);
899 if (cbinfo->server_cipher_list)
900 SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list);
901 #ifndef DISABLE_OCSP
902 if (cbinfo->u_ocsp.server.file)
903 {
904 SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb);
905 SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo);
906 }
907 #endif
908
909 rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server);
910 if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
911
912 /* do this after setup_certs, because this can require the certs for verifying
913 OCSP information. */
914 rc = tls_expand_session_files(server_sni, cbinfo);
915 if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
916
917 if (!init_dh(server_sni, cbinfo->dhparam, NULL))
918 return SSL_TLSEXT_ERR_NOACK;
919
920 DEBUG(D_tls) debug_printf("Switching SSL context.\n");
921 SSL_set_SSL_CTX(s, server_sni);
922
923 return SSL_TLSEXT_ERR_OK;
924 }
925 #endif /* EXIM_HAVE_OPENSSL_TLSEXT */
926
927
928
929
930 #ifndef DISABLE_OCSP
931
932 /*************************************************
933 * Callback to handle OCSP Stapling *
934 *************************************************/
935
936 /* Called when acting as server during the TLS session setup if the client
937 requests OCSP information with a Certificate Status Request.
938
939 Documentation via openssl s_server.c and the Apache patch from the OpenSSL
940 project.
941
942 */
943
944 static int
945 tls_server_stapling_cb(SSL *s, void *arg)
946 {
947 const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
948 uschar *response_der;
949 int response_der_len;
950
951 DEBUG(D_tls)
952 debug_printf("Received TLS status request (OCSP stapling); %s response.",
953 cbinfo->u_ocsp.server.response ? "have" : "lack");
954
955 tls_in.ocsp = OCSP_NOT_RESP;
956 if (!cbinfo->u_ocsp.server.response)
957 return SSL_TLSEXT_ERR_NOACK;
958
959 response_der = NULL;
960 response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response,
961 &response_der);
962 if (response_der_len <= 0)
963 return SSL_TLSEXT_ERR_NOACK;
964
965 SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len);
966 tls_in.ocsp = OCSP_VFIED;
967 return SSL_TLSEXT_ERR_OK;
968 }
969
970
971 static void
972 time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time)
973 {
974 BIO_printf(bp, "\t%s: ", str);
975 ASN1_GENERALIZEDTIME_print(bp, time);
976 BIO_puts(bp, "\n");
977 }
978
979 static int
980 tls_client_stapling_cb(SSL *s, void *arg)
981 {
982 tls_ext_ctx_cb * cbinfo = arg;
983 const unsigned char * p;
984 int len;
985 OCSP_RESPONSE * rsp;
986 OCSP_BASICRESP * bs;
987 int i;
988
989 DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):");
990 len = SSL_get_tlsext_status_ocsp_resp(s, &p);
991 if(!p)
992 {
993 /* Expect this when we requested ocsp but got none */
994 if ( cbinfo->u_ocsp.client.verify_required
995 && log_extra_selector & LX_tls_cipher)
996 log_write(0, LOG_MAIN, "Received TLS status callback, null content");
997 else
998 DEBUG(D_tls) debug_printf(" null\n");
999 return cbinfo->u_ocsp.client.verify_required ? 0 : 1;
1000 }
1001
1002 if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len)))
1003 {
1004 tls_out.ocsp = OCSP_FAILED;
1005 if (log_extra_selector & LX_tls_cipher)
1006 log_write(0, LOG_MAIN, "Received TLS cert status response, parse error");
1007 else
1008 DEBUG(D_tls) debug_printf(" parse error\n");
1009 return 0;
1010 }
1011
1012 if(!(bs = OCSP_response_get1_basic(rsp)))
1013 {
1014 tls_out.ocsp = OCSP_FAILED;
1015 if (log_extra_selector & LX_tls_cipher)
1016 log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response");
1017 else
1018 DEBUG(D_tls) debug_printf(" error parsing response\n");
1019 OCSP_RESPONSE_free(rsp);
1020 return 0;
1021 }
1022
1023 /* We'd check the nonce here if we'd put one in the request. */
1024 /* However that would defeat cacheability on the server so we don't. */
1025
1026 /* This section of code reworked from OpenSSL apps source;
1027 The OpenSSL Project retains copyright:
1028 Copyright (c) 1999 The OpenSSL Project. All rights reserved.
1029 */
1030 {
1031 BIO * bp = NULL;
1032 int status, reason;
1033 ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd;
1034
1035 DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE);
1036
1037 /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */
1038
1039 /* Use the chain that verified the server cert to verify the stapled info */
1040 /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */
1041
1042 if ((i = OCSP_basic_verify(bs, NULL,
1043 cbinfo->u_ocsp.client.verify_store, 0)) <= 0)
1044 {
1045 tls_out.ocsp = OCSP_FAILED;
1046 if (log_extra_selector & LX_tls_cipher)
1047 log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable");
1048 BIO_printf(bp, "OCSP response verify failure\n");
1049 ERR_print_errors(bp);
1050 i = cbinfo->u_ocsp.client.verify_required ? 0 : 1;
1051 goto out;
1052 }
1053
1054 BIO_printf(bp, "OCSP response well-formed and signed OK\n");
1055
1056 {
1057 STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses;
1058 OCSP_SINGLERESP * single;
1059
1060 if (sk_OCSP_SINGLERESP_num(sresp) != 1)
1061 {
1062 tls_out.ocsp = OCSP_FAILED;
1063 log_write(0, LOG_MAIN, "OCSP stapling "
1064 "with multiple responses not handled");
1065 i = cbinfo->u_ocsp.client.verify_required ? 0 : 1;
1066 goto out;
1067 }
1068 single = OCSP_resp_get0(bs, 0);
1069 status = OCSP_single_get0_status(single, &reason, &rev,
1070 &thisupd, &nextupd);
1071 }
1072
1073 DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd);
1074 DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd);
1075 if (!OCSP_check_validity(thisupd, nextupd,
1076 EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
1077 {
1078 tls_out.ocsp = OCSP_FAILED;
1079 DEBUG(D_tls) ERR_print_errors(bp);
1080 log_write(0, LOG_MAIN, "Server OSCP dates invalid");
1081 i = cbinfo->u_ocsp.client.verify_required ? 0 : 1;
1082 }
1083 else
1084 {
1085 DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n",
1086 OCSP_cert_status_str(status));
1087 switch(status)
1088 {
1089 case V_OCSP_CERTSTATUS_GOOD:
1090 tls_out.ocsp = OCSP_VFIED;
1091 i = 1;
1092 break;
1093 case V_OCSP_CERTSTATUS_REVOKED:
1094 tls_out.ocsp = OCSP_FAILED;
1095 log_write(0, LOG_MAIN, "Server certificate revoked%s%s",
1096 reason != -1 ? "; reason: " : "",
1097 reason != -1 ? OCSP_crl_reason_str(reason) : "");
1098 DEBUG(D_tls) time_print(bp, "Revocation Time", rev);
1099 i = cbinfo->u_ocsp.client.verify_required ? 0 : 1;
1100 break;
1101 default:
1102 tls_out.ocsp = OCSP_FAILED;
1103 log_write(0, LOG_MAIN,
1104 "Server certificate status unknown, in OCSP stapling");
1105 i = cbinfo->u_ocsp.client.verify_required ? 0 : 1;
1106 break;
1107 }
1108 }
1109 out:
1110 BIO_free(bp);
1111 }
1112
1113 OCSP_RESPONSE_free(rsp);
1114 return i;
1115 }
1116 #endif /*!DISABLE_OCSP*/
1117
1118
1119 /*************************************************
1120 * Initialize for TLS *
1121 *************************************************/
1122
1123 /* Called from both server and client code, to do preliminary initialization
1124 of the library. We allocate and return a context structure.
1125
1126 Arguments:
1127 ctxp returned SSL context
1128 host connected host, if client; NULL if server
1129 dhparam DH parameter file
1130 certificate certificate file
1131 privatekey private key
1132 ocsp_file file of stapling info (server); flag for require ocsp (client)
1133 addr address if client; NULL if server (for some randomness)
1134 cbp place to put allocated callback context
1135
1136 Returns: OK/DEFER/FAIL
1137 */
1138
1139 static int
1140 tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate,
1141 uschar *privatekey,
1142 #ifndef DISABLE_OCSP
1143 uschar *ocsp_file,
1144 #endif
1145 address_item *addr, tls_ext_ctx_cb ** cbp)
1146 {
1147 long init_options;
1148 int rc;
1149 BOOL okay;
1150 tls_ext_ctx_cb * cbinfo;
1151
1152 cbinfo = store_malloc(sizeof(tls_ext_ctx_cb));
1153 cbinfo->certificate = certificate;
1154 cbinfo->privatekey = privatekey;
1155 #ifndef DISABLE_OCSP
1156 if ((cbinfo->is_server = host==NULL))
1157 {
1158 cbinfo->u_ocsp.server.file = ocsp_file;
1159 cbinfo->u_ocsp.server.file_expanded = NULL;
1160 cbinfo->u_ocsp.server.response = NULL;
1161 }
1162 else
1163 cbinfo->u_ocsp.client.verify_store = NULL;
1164 #endif
1165 cbinfo->dhparam = dhparam;
1166 cbinfo->server_cipher_list = NULL;
1167 cbinfo->host = host;
1168 #ifdef EXPERIMENTAL_EVENT
1169 cbinfo->event_action = NULL;
1170 #endif
1171
1172 SSL_load_error_strings(); /* basic set up */
1173 OpenSSL_add_ssl_algorithms();
1174
1175 #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
1176 /* SHA256 is becoming ever more popular. This makes sure it gets added to the
1177 list of available digests. */
1178 EVP_add_digest(EVP_sha256());
1179 #endif
1180
1181 /* Create a context.
1182 The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant
1183 negotiation in the different methods; as far as I can tell, the only
1184 *_{server,client}_method which allows negotiation is SSLv23, which exists even
1185 when OpenSSL is built without SSLv2 support.
1186 By disabling with openssl_options, we can let admins re-enable with the
1187 existing knob. */
1188
1189 *ctxp = SSL_CTX_new((host == NULL)?
1190 SSLv23_server_method() : SSLv23_client_method());
1191
1192 if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL);
1193
1194 /* It turns out that we need to seed the random number generator this early in
1195 order to get the full complement of ciphers to work. It took me roughly a day
1196 of work to discover this by experiment.
1197
1198 On systems that have /dev/urandom, SSL may automatically seed itself from
1199 there. Otherwise, we have to make something up as best we can. Double check
1200 afterwards. */
1201
1202 if (!RAND_status())
1203 {
1204 randstuff r;
1205 gettimeofday(&r.tv, NULL);
1206 r.p = getpid();
1207
1208 RAND_seed((uschar *)(&r), sizeof(r));
1209 RAND_seed((uschar *)big_buffer, big_buffer_size);
1210 if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr));
1211
1212 if (!RAND_status())
1213 return tls_error(US"RAND_status", host,
1214 US"unable to seed random number generator");
1215 }
1216
1217 /* Set up the information callback, which outputs if debugging is at a suitable
1218 level. */
1219
1220 SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback);
1221
1222 /* Automatically re-try reads/writes after renegotiation. */
1223 (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY);
1224
1225 /* Apply administrator-supplied work-arounds.
1226 Historically we applied just one requested option,
1227 SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we
1228 moved to an administrator-controlled list of options to specify and
1229 grandfathered in the first one as the default value for "openssl_options".
1230
1231 No OpenSSL version number checks: the options we accept depend upon the
1232 availability of the option value macros from OpenSSL. */
1233
1234 okay = tls_openssl_options_parse(openssl_options, &init_options);
1235 if (!okay)
1236 return tls_error(US"openssl_options parsing failed", host, NULL);
1237
1238 if (init_options)
1239 {
1240 DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options);
1241 if (!(SSL_CTX_set_options(*ctxp, init_options)))
1242 return tls_error(string_sprintf(
1243 "SSL_CTX_set_option(%#lx)", init_options), host, NULL);
1244 }
1245 else
1246 DEBUG(D_tls) debug_printf("no SSL CTX options to set\n");
1247
1248 /* Initialize with DH parameters if supplied */
1249
1250 if (!init_dh(*ctxp, dhparam, host)) return DEFER;
1251
1252 /* Set up certificate and key (and perhaps OCSP info) */
1253
1254 rc = tls_expand_session_files(*ctxp, cbinfo);
1255 if (rc != OK) return rc;
1256
1257 /* If we need to handle SNI, do so */
1258 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
1259 if (host == NULL) /* server */
1260 {
1261 # ifndef DISABLE_OCSP
1262 /* We check u_ocsp.server.file, not server.response, because we care about if
1263 the option exists, not what the current expansion might be, as SNI might
1264 change the certificate and OCSP file in use between now and the time the
1265 callback is invoked. */
1266 if (cbinfo->u_ocsp.server.file)
1267 {
1268 SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb);
1269 SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo);
1270 }
1271 # endif
1272 /* We always do this, so that $tls_sni is available even if not used in
1273 tls_certificate */
1274 SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb);
1275 SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo);
1276 }
1277 # ifndef DISABLE_OCSP
1278 else /* client */
1279 if(ocsp_file) /* wanting stapling */
1280 {
1281 if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new()))
1282 {
1283 DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n");
1284 return FAIL;
1285 }
1286 SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb);
1287 SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo);
1288 }
1289 # endif
1290 #endif
1291
1292 #ifdef EXPERIMENTAL_CERTNAMES
1293 cbinfo->verify_cert_hostnames = NULL;
1294 #endif
1295
1296 /* Set up the RSA callback */
1297
1298 SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback);
1299
1300 /* Finally, set the timeout, and we are done */
1301
1302 SSL_CTX_set_timeout(*ctxp, ssl_session_timeout);
1303 DEBUG(D_tls) debug_printf("Initialized TLS\n");
1304
1305 *cbp = cbinfo;
1306
1307 return OK;
1308 }
1309
1310
1311
1312
1313 /*************************************************
1314 * Get name of cipher in use *
1315 *************************************************/
1316
1317 /*
1318 Argument: pointer to an SSL structure for the connection
1319 buffer to use for answer
1320 size of buffer
1321 pointer to number of bits for cipher
1322 Returns: nothing
1323 */
1324
1325 static void
1326 construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits)
1327 {
1328 /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't
1329 yet reflect that. It should be a safe change anyway, even 0.9.8 versions have
1330 the accessor functions use const in the prototype. */
1331 const SSL_CIPHER *c;
1332 const uschar *ver;
1333
1334 ver = (const uschar *)SSL_get_version(ssl);
1335
1336 c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl);
1337 SSL_CIPHER_get_bits(c, bits);
1338
1339 string_format(cipherbuf, bsize, "%s:%s:%u", ver,
1340 SSL_CIPHER_get_name(c), *bits);
1341
1342 DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf);
1343 }
1344
1345
1346
1347
1348
1349 /*************************************************
1350 * Set up for verifying certificates *
1351 *************************************************/
1352
1353 /* Called by both client and server startup
1354
1355 Arguments:
1356 sctx SSL_CTX* to initialise
1357 certs certs file or NULL
1358 crl CRL file or NULL
1359 host NULL in a server; the remote host in a client
1360 optional TRUE if called from a server for a host in tls_try_verify_hosts;
1361 otherwise passed as FALSE
1362 cert_vfy_cb Callback function for certificate verification
1363
1364 Returns: OK/DEFER/FAIL
1365 */
1366
1367 static int
1368 setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
1369 int (*cert_vfy_cb)(int, X509_STORE_CTX *) )
1370 {
1371 uschar *expcerts, *expcrl;
1372
1373 if (!expand_check(certs, US"tls_verify_certificates", &expcerts))
1374 return DEFER;
1375
1376 if (expcerts != NULL && *expcerts != '\0')
1377 {
1378 struct stat statbuf;
1379 if (!SSL_CTX_set_default_verify_paths(sctx))
1380 return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL);
1381
1382 if (Ustat(expcerts, &statbuf) < 0)
1383 {
1384 log_write(0, LOG_MAIN|LOG_PANIC,
1385 "failed to stat %s for certificates", expcerts);
1386 return DEFER;
1387 }
1388 else
1389 {
1390 uschar *file, *dir;
1391 if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
1392 { file = NULL; dir = expcerts; }
1393 else
1394 { file = expcerts; dir = NULL; }
1395
1396 /* If a certificate file is empty, the next function fails with an
1397 unhelpful error message. If we skip it, we get the correct behaviour (no
1398 certificates are recognized, but the error message is still misleading (it
1399 says no certificate was supplied.) But this is better. */
1400
1401 if ((file == NULL || statbuf.st_size > 0) &&
1402 !SSL_CTX_load_verify_locations(sctx, CS file, CS dir))
1403 return tls_error(US"SSL_CTX_load_verify_locations", host, NULL);
1404
1405 /* Load the list of CAs for which we will accept certs, for sending
1406 to the client. This is only for the one-file tls_verify_certificates
1407 variant.
1408 If a list isn't loaded into the server, but
1409 some verify locations are set, the server end appears to make
1410 a wildcard reqest for client certs.
1411 Meanwhile, the client library as deafult behaviour *ignores* the list
1412 we send over the wire - see man SSL_CTX_set_client_cert_cb.
1413 Because of this, and that the dir variant is likely only used for
1414 the public-CA bundle (not for a private CA), not worth fixing.
1415 */
1416 if (file != NULL)
1417 {
1418 STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file);
1419 DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n",
1420 sk_X509_NAME_num(names));
1421 SSL_CTX_set_client_CA_list(sctx, names);
1422 }
1423 }
1424
1425 /* Handle a certificate revocation list. */
1426
1427 #if OPENSSL_VERSION_NUMBER > 0x00907000L
1428
1429 /* This bit of code is now the version supplied by Lars Mainka. (I have
1430 * merely reformatted it into the Exim code style.)
1431
1432 * "From here I changed the code to add support for multiple crl's
1433 * in pem format in one file or to support hashed directory entries in
1434 * pem format instead of a file. This method now uses the library function
1435 * X509_STORE_load_locations to add the CRL location to the SSL context.
1436 * OpenSSL will then handle the verify against CA certs and CRLs by
1437 * itself in the verify callback." */
1438
1439 if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER;
1440 if (expcrl != NULL && *expcrl != 0)
1441 {
1442 struct stat statbufcrl;
1443 if (Ustat(expcrl, &statbufcrl) < 0)
1444 {
1445 log_write(0, LOG_MAIN|LOG_PANIC,
1446 "failed to stat %s for certificates revocation lists", expcrl);
1447 return DEFER;
1448 }
1449 else
1450 {
1451 /* is it a file or directory? */
1452 uschar *file, *dir;
1453 X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx);
1454 if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR)
1455 {
1456 file = NULL;
1457 dir = expcrl;
1458 DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir);
1459 }
1460 else
1461 {
1462 file = expcrl;
1463 dir = NULL;
1464 DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file);
1465 }
1466 if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0)
1467 return tls_error(US"X509_STORE_load_locations", host, NULL);
1468
1469 /* setting the flags to check against the complete crl chain */
1470
1471 X509_STORE_set_flags(cvstore,
1472 X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
1473 }
1474 }
1475
1476 #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
1477
1478 /* If verification is optional, don't fail if no certificate */
1479
1480 SSL_CTX_set_verify(sctx,
1481 SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT),
1482 cert_vfy_cb);
1483 }
1484
1485 return OK;
1486 }
1487
1488
1489
1490 /*************************************************
1491 * Start a TLS session in a server *
1492 *************************************************/
1493
1494 /* This is called when Exim is running as a server, after having received
1495 the STARTTLS command. It must respond to that command, and then negotiate
1496 a TLS session.
1497
1498 Arguments:
1499 require_ciphers allowed ciphers
1500
1501 Returns: OK on success
1502 DEFER for errors before the start of the negotiation
1503 FAIL for errors during the negotation; the server can't
1504 continue running.
1505 */
1506
1507 int
1508 tls_server_start(const uschar *require_ciphers)
1509 {
1510 int rc;
1511 uschar *expciphers;
1512 tls_ext_ctx_cb *cbinfo;
1513 static uschar cipherbuf[256];
1514
1515 /* Check for previous activation */
1516
1517 if (tls_in.active >= 0)
1518 {
1519 tls_error(US"STARTTLS received after TLS started", NULL, US"");
1520 smtp_printf("554 Already in TLS\r\n");
1521 return FAIL;
1522 }
1523
1524 /* Initialize the SSL library. If it fails, it will already have logged
1525 the error. */
1526
1527 rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey,
1528 #ifndef DISABLE_OCSP
1529 tls_ocsp_file,
1530 #endif
1531 NULL, &server_static_cbinfo);
1532 if (rc != OK) return rc;
1533 cbinfo = server_static_cbinfo;
1534
1535 if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers))
1536 return FAIL;
1537
1538 /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
1539 were historically separated by underscores. So that I can use either form in my
1540 tests, and also for general convenience, we turn underscores into hyphens here.
1541 */
1542
1543 if (expciphers != NULL)
1544 {
1545 uschar *s = expciphers;
1546 while (*s != 0) { if (*s == '_') *s = '-'; s++; }
1547 DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
1548 if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers))
1549 return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL);
1550 cbinfo->server_cipher_list = expciphers;
1551 }
1552
1553 /* If this is a host for which certificate verification is mandatory or
1554 optional, set up appropriately. */
1555
1556 tls_in.certificate_verified = FALSE;
1557 #ifdef EXPERIMENTAL_DANE
1558 tls_in.dane_verified = FALSE;
1559 #endif
1560 server_verify_callback_called = FALSE;
1561
1562 if (verify_check_host(&tls_verify_hosts) == OK)
1563 {
1564 rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
1565 FALSE, verify_callback_server);
1566 if (rc != OK) return rc;
1567 server_verify_optional = FALSE;
1568 }
1569 else if (verify_check_host(&tls_try_verify_hosts) == OK)
1570 {
1571 rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
1572 TRUE, verify_callback_server);
1573 if (rc != OK) return rc;
1574 server_verify_optional = TRUE;
1575 }
1576
1577 /* Prepare for new connection */
1578
1579 if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL);
1580
1581 /* Warning: we used to SSL_clear(ssl) here, it was removed.
1582 *
1583 * With the SSL_clear(), we get strange interoperability bugs with
1584 * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in
1585 * OpenSSL itself, as a clear should not lead to inability to follow protocols.
1586 *
1587 * The SSL_clear() call is to let an existing SSL* be reused, typically after
1588 * session shutdown. In this case, we have a brand new object and there's no
1589 * obvious reason to immediately clear it. I'm guessing that this was
1590 * originally added because of incomplete initialisation which the clear fixed,
1591 * in some historic release.
1592 */
1593
1594 /* Set context and tell client to go ahead, except in the case of TLS startup
1595 on connection, where outputting anything now upsets the clients and tends to
1596 make them disconnect. We need to have an explicit fflush() here, to force out
1597 the response. Other smtp_printf() calls do not need it, because in non-TLS
1598 mode, the fflush() happens when smtp_getc() is called. */
1599
1600 SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx));
1601 if (!tls_in.on_connect)
1602 {
1603 smtp_printf("220 TLS go ahead\r\n");
1604 fflush(smtp_out);
1605 }
1606
1607 /* Now negotiate the TLS session. We put our own timer on it, since it seems
1608 that the OpenSSL library doesn't. */
1609
1610 SSL_set_wfd(server_ssl, fileno(smtp_out));
1611 SSL_set_rfd(server_ssl, fileno(smtp_in));
1612 SSL_set_accept_state(server_ssl);
1613
1614 DEBUG(D_tls) debug_printf("Calling SSL_accept\n");
1615
1616 sigalrm_seen = FALSE;
1617 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
1618 rc = SSL_accept(server_ssl);
1619 alarm(0);
1620
1621 if (rc <= 0)
1622 {
1623 tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL);
1624 if (ERR_get_error() == 0)
1625 log_write(0, LOG_MAIN,
1626 "TLS client disconnected cleanly (rejected our certificate?)");
1627 return FAIL;
1628 }
1629
1630 DEBUG(D_tls) debug_printf("SSL_accept was successful\n");
1631
1632 /* TLS has been set up. Adjust the input functions to read via TLS,
1633 and initialize things. */
1634
1635 construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits);
1636 tls_in.cipher = cipherbuf;
1637
1638 DEBUG(D_tls)
1639 {
1640 uschar buf[2048];
1641 if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL)
1642 debug_printf("Shared ciphers: %s\n", buf);
1643 }
1644
1645 /* Record the certificate we presented */
1646 {
1647 X509 * crt = SSL_get_certificate(server_ssl);
1648 tls_in.ourcert = crt ? X509_dup(crt) : NULL;
1649 }
1650
1651 /* Only used by the server-side tls (tls_in), including tls_getc.
1652 Client-side (tls_out) reads (seem to?) go via
1653 smtp_read_response()/ip_recv().
1654 Hence no need to duplicate for _in and _out.
1655 */
1656 ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size);
1657 ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0;
1658 ssl_xfer_eof = ssl_xfer_error = 0;
1659
1660 receive_getc = tls_getc;
1661 receive_ungetc = tls_ungetc;
1662 receive_feof = tls_feof;
1663 receive_ferror = tls_ferror;
1664 receive_smtp_buffered = tls_smtp_buffered;
1665
1666 tls_in.active = fileno(smtp_out);
1667 return OK;
1668 }
1669
1670
1671
1672
1673 static int
1674 tls_client_basic_ctx_init(SSL_CTX * ctx,
1675 host_item * host, smtp_transport_options_block * ob
1676 #ifdef EXPERIMENTAL_CERTNAMES
1677 , tls_ext_ctx_cb * cbinfo
1678 #endif
1679 )
1680 {
1681 int rc;
1682 /* stick to the old behaviour for compatibility if tls_verify_certificates is
1683 set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only
1684 the specified host patterns if one of them is defined */
1685
1686 if ((!ob->tls_verify_hosts && !ob->tls_try_verify_hosts) ||
1687 (verify_check_host(&ob->tls_verify_hosts) == OK))
1688 {
1689 if ((rc = setup_certs(ctx, ob->tls_verify_certificates,
1690 ob->tls_crl, host, FALSE, verify_callback_client)) != OK)
1691 return rc;
1692 client_verify_optional = FALSE;
1693
1694 #ifdef EXPERIMENTAL_CERTNAMES
1695 if (ob->tls_verify_cert_hostnames)
1696 {
1697 if (!expand_check(ob->tls_verify_cert_hostnames,
1698 US"tls_verify_cert_hostnames",
1699 &cbinfo->verify_cert_hostnames))
1700 return FAIL;
1701 if (cbinfo->verify_cert_hostnames)
1702 DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n",
1703 cbinfo->verify_cert_hostnames);
1704 }
1705 #endif
1706 }
1707 else if (verify_check_host(&ob->tls_try_verify_hosts) == OK)
1708 {
1709 if ((rc = setup_certs(ctx, ob->tls_verify_certificates,
1710 ob->tls_crl, host, TRUE, verify_callback_client)) != OK)
1711 return rc;
1712 client_verify_optional = TRUE;
1713 }
1714
1715 return OK;
1716 }
1717
1718
1719 #ifdef EXPERIMENTAL_DANE
1720 static int
1721 dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa)
1722 {
1723 dns_record * rr;
1724 dns_scan dnss;
1725 const char * hostnames[2] = { CS host->name, NULL };
1726 int found = 0;
1727
1728 if (DANESSL_init(ssl, NULL, hostnames) != 1)
1729 return tls_error(US"hostnames load", host, NULL);
1730
1731 for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1732 rr;
1733 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)
1734 ) if (rr->type == T_TLSA)
1735 {
1736 uschar * p = rr->data;
1737 uint8_t usage, selector, mtype;
1738 const char * mdname;
1739
1740 usage = *p++;
1741
1742 /* Only DANE-TA(2) and DANE-EE(3) are supported */
1743 if (usage != 2 && usage != 3) continue;
1744
1745 selector = *p++;
1746 mtype = *p++;
1747
1748 switch (mtype)
1749 {
1750 default: continue; /* Only match-types 0, 1, 2 are supported */
1751 case 0: mdname = NULL; break;
1752 case 1: mdname = "sha256"; break;
1753 case 2: mdname = "sha512"; break;
1754 }
1755
1756 found++;
1757 switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3))
1758 {
1759 default:
1760 case 0: /* action not taken */
1761 return tls_error(US"tlsa load", host, NULL);
1762 case 1: break;
1763 }
1764
1765 tls_out.tlsa_usage |= 1<<usage;
1766 }
1767
1768 if (found)
1769 return OK;
1770
1771 log_write(0, LOG_MAIN, "DANE error: No usable TLSA records");
1772 return FAIL;
1773 }
1774 #endif /*EXPERIMENTAL_DANE*/
1775
1776
1777
1778 /*************************************************
1779 * Start a TLS session in a client *
1780 *************************************************/
1781
1782 /* Called from the smtp transport after STARTTLS has been accepted.
1783
1784 Argument:
1785 fd the fd of the connection
1786 host connected host (for messages)
1787 addr the first address
1788 tb transport (always smtp)
1789 tlsa_dnsa tlsa lookup, if DANE, else null
1790
1791 Returns: OK on success
1792 FAIL otherwise - note that tls_error() will not give DEFER
1793 because this is not a server
1794 */
1795
1796 int
1797 tls_client_start(int fd, host_item *host, address_item *addr,
1798 transport_instance *tb
1799 #ifdef EXPERIMENTAL_DANE
1800 , dns_answer * tlsa_dnsa
1801 #endif
1802 )
1803 {
1804 smtp_transport_options_block * ob =
1805 (smtp_transport_options_block *)tb->options_block;
1806 static uschar txt[256];
1807 uschar * expciphers;
1808 X509 * server_cert;
1809 int rc;
1810 static uschar cipherbuf[256];
1811
1812 #ifndef DISABLE_OCSP
1813 BOOL request_ocsp = FALSE;
1814 BOOL require_ocsp = FALSE;
1815 #endif
1816
1817 #ifdef EXPERIMENTAL_DANE
1818 tls_out.tlsa_usage = 0;
1819 #endif
1820
1821 #ifndef DISABLE_OCSP
1822 {
1823 # ifdef EXPERIMENTAL_DANE
1824 if ( tlsa_dnsa
1825 && ob->hosts_request_ocsp[0] == '*'
1826 && ob->hosts_request_ocsp[1] == '\0'
1827 )
1828 {
1829 /* Unchanged from default. Use a safer one under DANE */
1830 request_ocsp = TRUE;
1831 ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} "
1832 " {= {4}{$tls_out_tlsa_usage}} } "
1833 " {*}{}}";
1834 }
1835 # endif
1836
1837 if ((require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp,
1838 NULL, host->name, host->address, NULL) == OK))
1839 request_ocsp = TRUE;
1840 else
1841 # ifdef EXPERIMENTAL_DANE
1842 if (!request_ocsp)
1843 # endif
1844 request_ocsp = verify_check_this_host(&ob->hosts_request_ocsp,
1845 NULL, host->name, host->address, NULL) == OK;
1846 }
1847 #endif
1848
1849 rc = tls_init(&client_ctx, host, NULL,
1850 ob->tls_certificate, ob->tls_privatekey,
1851 #ifndef DISABLE_OCSP
1852 (void *)(long)request_ocsp,
1853 #endif
1854 addr, &client_static_cbinfo);
1855 if (rc != OK) return rc;
1856
1857 tls_out.certificate_verified = FALSE;
1858 client_verify_callback_called = FALSE;
1859
1860 if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers",
1861 &expciphers))
1862 return FAIL;
1863
1864 /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
1865 are separated by underscores. So that I can use either form in my tests, and
1866 also for general convenience, we turn underscores into hyphens here. */
1867
1868 if (expciphers != NULL)
1869 {
1870 uschar *s = expciphers;
1871 while (*s != 0) { if (*s == '_') *s = '-'; s++; }
1872 DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
1873 if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers))
1874 return tls_error(US"SSL_CTX_set_cipher_list", host, NULL);
1875 }
1876
1877 #ifdef EXPERIMENTAL_DANE
1878 if (tlsa_dnsa)
1879 {
1880 SSL_CTX_set_verify(client_ctx, SSL_VERIFY_PEER, verify_callback_client_dane);
1881
1882 if (!DANESSL_library_init())
1883 return tls_error(US"library init", host, NULL);
1884 if (DANESSL_CTX_init(client_ctx) <= 0)
1885 return tls_error(US"context init", host, NULL);
1886 }
1887 else
1888
1889 #endif
1890
1891 if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob
1892 #ifdef EXPERIMENTAL_CERTNAMES
1893 , client_static_cbinfo
1894 #endif
1895 )) != OK)
1896 return rc;
1897
1898 if ((client_ssl = SSL_new(client_ctx)) == NULL)
1899 return tls_error(US"SSL_new", host, NULL);
1900 SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx));
1901 SSL_set_fd(client_ssl, fd);
1902 SSL_set_connect_state(client_ssl);
1903
1904 if (ob->tls_sni)
1905 {
1906 if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni))
1907 return FAIL;
1908 if (tls_out.sni == NULL)
1909 {
1910 DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n");
1911 }
1912 else if (!Ustrlen(tls_out.sni))
1913 tls_out.sni = NULL;
1914 else
1915 {
1916 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
1917 DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni);
1918 SSL_set_tlsext_host_name(client_ssl, tls_out.sni);
1919 #else
1920 DEBUG(D_tls)
1921 debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n",
1922 tls_out.sni);
1923 #endif
1924 }
1925 }
1926
1927 #ifdef EXPERIMENTAL_DANE
1928 if (tlsa_dnsa)
1929 if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa)) != OK)
1930 return rc;
1931 #endif
1932
1933 #ifndef DISABLE_OCSP
1934 /* Request certificate status at connection-time. If the server
1935 does OCSP stapling we will get the callback (set in tls_init()) */
1936 # ifdef EXPERIMENTAL_DANE
1937 if (request_ocsp)
1938 {
1939 const uschar * s;
1940 if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage"))
1941 || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage"))
1942 )
1943 { /* Re-eval now $tls_out_tlsa_usage is populated. If
1944 this means we avoid the OCSP request, we wasted the setup
1945 cost in tls_init(). */
1946 require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp,
1947 NULL, host->name, host->address, NULL) == OK;
1948 request_ocsp = require_ocsp ? TRUE
1949 : verify_check_this_host(&ob->hosts_request_ocsp,
1950 NULL, host->name, host->address, NULL) == OK;
1951 }
1952 }
1953 # endif
1954
1955 if (request_ocsp)
1956 {
1957 SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp);
1958 client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp;
1959 tls_out.ocsp = OCSP_NOT_RESP;
1960 }
1961 #endif
1962
1963 #ifdef EXPERIMENTAL_EVENT
1964 client_static_cbinfo->event_action = tb->event_action;
1965 #endif
1966
1967 /* There doesn't seem to be a built-in timeout on connection. */
1968
1969 DEBUG(D_tls) debug_printf("Calling SSL_connect\n");
1970 sigalrm_seen = FALSE;
1971 alarm(ob->command_timeout);
1972 rc = SSL_connect(client_ssl);
1973 alarm(0);
1974
1975 #ifdef EXPERIMENTAL_DANE
1976 if (tlsa_dnsa)
1977 DANESSL_cleanup(client_ssl);
1978 #endif
1979
1980 if (rc <= 0)
1981 return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL);
1982
1983 DEBUG(D_tls) debug_printf("SSL_connect succeeded\n");
1984
1985 /* Beware anonymous ciphers which lead to server_cert being NULL */
1986 /*XXX server_cert is never freed... use X509_free() */
1987 server_cert = SSL_get_peer_certificate (client_ssl);
1988 if (server_cert)
1989 {
1990 tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert),
1991 CS txt, sizeof(txt));
1992 tls_out.peerdn = txt; /*XXX a static buffer... */
1993 }
1994 else
1995 tls_out.peerdn = NULL;
1996
1997 construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits);
1998 tls_out.cipher = cipherbuf;
1999
2000 /* Record the certificate we presented */
2001 {
2002 X509 * crt = SSL_get_certificate(client_ssl);
2003 tls_out.ourcert = crt ? X509_dup(crt) : NULL;
2004 }
2005
2006 tls_out.active = fd;
2007 return OK;
2008 }
2009
2010
2011
2012
2013
2014 /*************************************************
2015 * TLS version of getc *
2016 *************************************************/
2017
2018 /* This gets the next byte from the TLS input buffer. If the buffer is empty,
2019 it refills the buffer via the SSL reading function.
2020
2021 Arguments: none
2022 Returns: the next character or EOF
2023
2024 Only used by the server-side TLS.
2025 */
2026
2027 int
2028 tls_getc(void)
2029 {
2030 if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm)
2031 {
2032 int error;
2033 int inbytes;
2034
2035 DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl,
2036 ssl_xfer_buffer, ssl_xfer_buffer_size);
2037
2038 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
2039 inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size);
2040 error = SSL_get_error(server_ssl, inbytes);
2041 alarm(0);
2042
2043 /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been
2044 closed down, not that the socket itself has been closed down. Revert to
2045 non-SSL handling. */
2046
2047 if (error == SSL_ERROR_ZERO_RETURN)
2048 {
2049 DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
2050
2051 receive_getc = smtp_getc;
2052 receive_ungetc = smtp_ungetc;
2053 receive_feof = smtp_feof;
2054 receive_ferror = smtp_ferror;
2055 receive_smtp_buffered = smtp_buffered;
2056
2057 SSL_free(server_ssl);
2058 server_ssl = NULL;
2059 tls_in.active = -1;
2060 tls_in.bits = 0;
2061 tls_in.cipher = NULL;
2062 tls_in.peerdn = NULL;
2063 tls_in.sni = NULL;
2064
2065 return smtp_getc();
2066 }
2067
2068 /* Handle genuine errors */
2069
2070 else if (error == SSL_ERROR_SSL)
2071 {
2072 ERR_error_string(ERR_get_error(), ssl_errstring);
2073 log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring);
2074 ssl_xfer_error = 1;
2075 return EOF;
2076 }
2077
2078 else if (error != SSL_ERROR_NONE)
2079 {
2080 DEBUG(D_tls) debug_printf("Got SSL error %d\n", error);
2081 ssl_xfer_error = 1;
2082 return EOF;
2083 }
2084
2085 #ifndef DISABLE_DKIM
2086 dkim_exim_verify_feed(ssl_xfer_buffer, inbytes);
2087 #endif
2088 ssl_xfer_buffer_hwm = inbytes;
2089 ssl_xfer_buffer_lwm = 0;
2090 }
2091
2092 /* Something in the buffer; return next uschar */
2093
2094 return ssl_xfer_buffer[ssl_xfer_buffer_lwm++];
2095 }
2096
2097
2098
2099 /*************************************************
2100 * Read bytes from TLS channel *
2101 *************************************************/
2102
2103 /*
2104 Arguments:
2105 buff buffer of data
2106 len size of buffer
2107
2108 Returns: the number of bytes read
2109 -1 after a failed read
2110
2111 Only used by the client-side TLS.
2112 */
2113
2114 int
2115 tls_read(BOOL is_server, uschar *buff, size_t len)
2116 {
2117 SSL *ssl = is_server ? server_ssl : client_ssl;
2118 int inbytes;
2119 int error;
2120
2121 DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl,
2122 buff, (unsigned int)len);
2123
2124 inbytes = SSL_read(ssl, CS buff, len);
2125 error = SSL_get_error(ssl, inbytes);
2126
2127 if (error == SSL_ERROR_ZERO_RETURN)
2128 {
2129 DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
2130 return -1;
2131 }
2132 else if (error != SSL_ERROR_NONE)
2133 {
2134 return -1;
2135 }
2136
2137 return inbytes;
2138 }
2139
2140
2141
2142
2143
2144 /*************************************************
2145 * Write bytes down TLS channel *
2146 *************************************************/
2147
2148 /*
2149 Arguments:
2150 is_server channel specifier
2151 buff buffer of data
2152 len number of bytes
2153
2154 Returns: the number of bytes after a successful write,
2155 -1 after a failed write
2156
2157 Used by both server-side and client-side TLS.
2158 */
2159
2160 int
2161 tls_write(BOOL is_server, const uschar *buff, size_t len)
2162 {
2163 int outbytes;
2164 int error;
2165 int left = len;
2166 SSL *ssl = is_server ? server_ssl : client_ssl;
2167
2168 DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left);
2169 while (left > 0)
2170 {
2171 DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left);
2172 outbytes = SSL_write(ssl, CS buff, left);
2173 error = SSL_get_error(ssl, outbytes);
2174 DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error);
2175 switch (error)
2176 {
2177 case SSL_ERROR_SSL:
2178 ERR_error_string(ERR_get_error(), ssl_errstring);
2179 log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring);
2180 return -1;
2181
2182 case SSL_ERROR_NONE:
2183 left -= outbytes;
2184 buff += outbytes;
2185 break;
2186
2187 case SSL_ERROR_ZERO_RETURN:
2188 log_write(0, LOG_MAIN, "SSL channel closed on write");
2189 return -1;
2190
2191 case SSL_ERROR_SYSCALL:
2192 log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s",
2193 sender_fullhost ? sender_fullhost : US"<unknown>",
2194 strerror(errno));
2195
2196 default:
2197 log_write(0, LOG_MAIN, "SSL_write error %d", error);
2198 return -1;
2199 }
2200 }
2201 return len;
2202 }
2203
2204
2205
2206 /*************************************************
2207 * Close down a TLS session *
2208 *************************************************/
2209
2210 /* This is also called from within a delivery subprocess forked from the
2211 daemon, to shut down the TLS library, without actually doing a shutdown (which
2212 would tamper with the SSL session in the parent process).
2213
2214 Arguments: TRUE if SSL_shutdown is to be called
2215 Returns: nothing
2216
2217 Used by both server-side and client-side TLS.
2218 */
2219
2220 void
2221 tls_close(BOOL is_server, BOOL shutdown)
2222 {
2223 SSL **sslp = is_server ? &server_ssl : &client_ssl;
2224 int *fdp = is_server ? &tls_in.active : &tls_out.active;
2225
2226 if (*fdp < 0) return; /* TLS was not active */
2227
2228 if (shutdown)
2229 {
2230 DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n");
2231 SSL_shutdown(*sslp);
2232 }
2233
2234 SSL_free(*sslp);
2235 *sslp = NULL;
2236
2237 *fdp = -1;
2238 }
2239
2240
2241
2242
2243 /*************************************************
2244 * Let tls_require_ciphers be checked at startup *
2245 *************************************************/
2246
2247 /* The tls_require_ciphers option, if set, must be something which the
2248 library can parse.
2249
2250 Returns: NULL on success, or error message
2251 */
2252
2253 uschar *
2254 tls_validate_require_cipher(void)
2255 {
2256 SSL_CTX *ctx;
2257 uschar *s, *expciphers, *err;
2258
2259 /* this duplicates from tls_init(), we need a better "init just global
2260 state, for no specific purpose" singleton function of our own */
2261
2262 SSL_load_error_strings();
2263 OpenSSL_add_ssl_algorithms();
2264 #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
2265 /* SHA256 is becoming ever more popular. This makes sure it gets added to the
2266 list of available digests. */
2267 EVP_add_digest(EVP_sha256());
2268 #endif
2269
2270 if (!(tls_require_ciphers && *tls_require_ciphers))
2271 return NULL;
2272
2273 if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers))
2274 return US"failed to expand tls_require_ciphers";
2275
2276 if (!(expciphers && *expciphers))
2277 return NULL;
2278
2279 /* normalisation ripped from above */
2280 s = expciphers;
2281 while (*s != 0) { if (*s == '_') *s = '-'; s++; }
2282
2283 err = NULL;
2284
2285 ctx = SSL_CTX_new(SSLv23_server_method());
2286 if (!ctx)
2287 {
2288 ERR_error_string(ERR_get_error(), ssl_errstring);
2289 return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring);
2290 }
2291
2292 DEBUG(D_tls)
2293 debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);
2294
2295 if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
2296 {
2297 ERR_error_string(ERR_get_error(), ssl_errstring);
2298 err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers);
2299 }
2300
2301 SSL_CTX_free(ctx);
2302
2303 return err;
2304 }
2305
2306
2307
2308
2309 /*************************************************
2310 * Report the library versions. *
2311 *************************************************/
2312
2313 /* There have historically been some issues with binary compatibility in
2314 OpenSSL libraries; if Exim (like many other applications) is built against
2315 one version of OpenSSL but the run-time linker picks up another version,
2316 it can result in serious failures, including crashing with a SIGSEGV. So
2317 report the version found by the compiler and the run-time version.
2318
2319 Note: some OS vendors backport security fixes without changing the version
2320 number/string, and the version date remains unchanged. The _build_ date
2321 will change, so we can more usefully assist with version diagnosis by also
2322 reporting the build date.
2323
2324 Arguments: a FILE* to print the results to
2325 Returns: nothing
2326 */
2327
2328 void
2329 tls_version_report(FILE *f)
2330 {
2331 fprintf(f, "Library version: OpenSSL: Compile: %s\n"
2332 " Runtime: %s\n"
2333 " : %s\n",
2334 OPENSSL_VERSION_TEXT,
2335 SSLeay_version(SSLEAY_VERSION),
2336 SSLeay_version(SSLEAY_BUILT_ON));
2337 /* third line is 38 characters for the %s and the line is 73 chars long;
2338 the OpenSSL output includes a "built on: " prefix already. */
2339 }
2340
2341
2342
2343
2344 /*************************************************
2345 * Random number generation *
2346 *************************************************/
2347
2348 /* Pseudo-random number generation. The result is not expected to be
2349 cryptographically strong but not so weak that someone will shoot themselves
2350 in the foot using it as a nonce in input in some email header scheme or
2351 whatever weirdness they'll twist this into. The result should handle fork()
2352 and avoid repeating sequences. OpenSSL handles that for us.
2353
2354 Arguments:
2355 max range maximum
2356 Returns a random number in range [0, max-1]
2357 */
2358
2359 int
2360 vaguely_random_number(int max)
2361 {
2362 unsigned int r;
2363 int i, needed_len;
2364 static pid_t pidlast = 0;
2365 pid_t pidnow;
2366 uschar *p;
2367 uschar smallbuf[sizeof(r)];
2368
2369 if (max <= 1)
2370 return 0;
2371
2372 pidnow = getpid();
2373 if (pidnow != pidlast)
2374 {
2375 /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state
2376 is unique for each thread", this doesn't apparently apply across processes,
2377 so our own warning from vaguely_random_number_fallback() applies here too.
2378 Fix per PostgreSQL. */
2379 if (pidlast != 0)
2380 RAND_cleanup();
2381 pidlast = pidnow;
2382 }
2383
2384 /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */
2385 if (!RAND_status())
2386 {
2387 randstuff r;
2388 gettimeofday(&r.tv, NULL);
2389 r.p = getpid();
2390
2391 RAND_seed((uschar *)(&r), sizeof(r));
2392 }
2393 /* We're after pseudo-random, not random; if we still don't have enough data
2394 in the internal PRNG then our options are limited. We could sleep and hope
2395 for entropy to come along (prayer technique) but if the system is so depleted
2396 in the first place then something is likely to just keep taking it. Instead,
2397 we'll just take whatever little bit of pseudo-random we can still manage to
2398 get. */
2399
2400 needed_len = sizeof(r);
2401 /* Don't take 8 times more entropy than needed if int is 8 octets and we were
2402 asked for a number less than 10. */
2403 for (r = max, i = 0; r; ++i)
2404 r >>= 1;
2405 i = (i + 7) / 8;
2406 if (i < needed_len)
2407 needed_len = i;
2408
2409 /* We do not care if crypto-strong */
2410 i = RAND_pseudo_bytes(smallbuf, needed_len);
2411 if (i < 0)
2412 {
2413 DEBUG(D_all)
2414 debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n");
2415 return vaguely_random_number_fallback(max);
2416 }
2417
2418 r = 0;
2419 for (p = smallbuf; needed_len; --needed_len, ++p)
2420 {
2421 r *= 256;
2422 r += *p;
2423 }
2424
2425 /* We don't particularly care about weighted results; if someone wants
2426 smooth distribution and cares enough then they should submit a patch then. */
2427 return r % max;
2428 }
2429
2430
2431
2432
2433 /*************************************************
2434 * OpenSSL option parse *
2435 *************************************************/
2436
2437 /* Parse one option for tls_openssl_options_parse below
2438
2439 Arguments:
2440 name one option name
2441 value place to store a value for it
2442 Returns success or failure in parsing
2443 */
2444
2445 struct exim_openssl_option {
2446 uschar *name;
2447 long value;
2448 };
2449 /* We could use a macro to expand, but we need the ifdef and not all the
2450 options document which version they were introduced in. Policylet: include
2451 all options unless explicitly for DTLS, let the administrator choose which
2452 to apply.
2453
2454 This list is current as of:
2455 ==> 1.0.1b <==
2456 Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev
2457 */
2458 static struct exim_openssl_option exim_openssl_options[] = {
2459 /* KEEP SORTED ALPHABETICALLY! */
2460 #ifdef SSL_OP_ALL
2461 { US"all", SSL_OP_ALL },
2462 #endif
2463 #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
2464 { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION },
2465 #endif
2466 #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE
2467 { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE },
2468 #endif
2469 #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
2470 { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS },
2471 #endif
2472 #ifdef SSL_OP_EPHEMERAL_RSA
2473 { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA },
2474 #endif
2475 #ifdef SSL_OP_LEGACY_SERVER_CONNECT
2476 { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT },
2477 #endif
2478 #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
2479 { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER },
2480 #endif
2481 #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG
2482 { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG },
2483 #endif
2484 #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING
2485 { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING },
2486 #endif
2487 #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG
2488 { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG },
2489 #endif
2490 #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
2491 { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG },
2492 #endif
2493 #ifdef SSL_OP_NO_COMPRESSION
2494 { US"no_compression", SSL_OP_NO_COMPRESSION },
2495 #endif
2496 #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
2497 { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION },
2498 #endif
2499 #ifdef SSL_OP_NO_SSLv2
2500 { US"no_sslv2", SSL_OP_NO_SSLv2 },
2501 #endif
2502 #ifdef SSL_OP_NO_SSLv3
2503 { US"no_sslv3", SSL_OP_NO_SSLv3 },
2504 #endif
2505 #ifdef SSL_OP_NO_TICKET
2506 { US"no_ticket", SSL_OP_NO_TICKET },
2507 #endif
2508 #ifdef SSL_OP_NO_TLSv1
2509 { US"no_tlsv1", SSL_OP_NO_TLSv1 },
2510 #endif
2511 #ifdef SSL_OP_NO_TLSv1_1
2512 #if SSL_OP_NO_TLSv1_1 == 0x00000400L
2513 /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */
2514 #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring
2515 #else
2516 { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 },
2517 #endif
2518 #endif
2519 #ifdef SSL_OP_NO_TLSv1_2
2520 { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 },
2521 #endif
2522 #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG
2523 { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG },
2524 #endif
2525 #ifdef SSL_OP_SINGLE_DH_USE
2526 { US"single_dh_use", SSL_OP_SINGLE_DH_USE },
2527 #endif
2528 #ifdef SSL_OP_SINGLE_ECDH_USE
2529 { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE },
2530 #endif
2531 #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG
2532 { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG },
2533 #endif
2534 #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
2535 { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG },
2536 #endif
2537 #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG
2538 { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG },
2539 #endif
2540 #ifdef SSL_OP_TLS_D5_BUG
2541 { US"tls_d5_bug", SSL_OP_TLS_D5_BUG },
2542 #endif
2543 #ifdef SSL_OP_TLS_ROLLBACK_BUG
2544 { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG },
2545 #endif
2546 };
2547 static int exim_openssl_options_size =
2548 sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option);
2549
2550
2551 static BOOL
2552 tls_openssl_one_option_parse(uschar *name, long *value)
2553 {
2554 int first = 0;
2555 int last = exim_openssl_options_size;
2556 while (last > first)
2557 {
2558 int middle = (first + last)/2;
2559 int c = Ustrcmp(name, exim_openssl_options[middle].name);
2560 if (c == 0)
2561 {
2562 *value = exim_openssl_options[middle].value;
2563 return TRUE;
2564 }
2565 else if (c > 0)
2566 first = middle + 1;
2567 else
2568 last = middle;
2569 }
2570 return FALSE;
2571 }
2572
2573
2574
2575
2576 /*************************************************
2577 * OpenSSL option parsing logic *
2578 *************************************************/
2579
2580 /* OpenSSL has a number of compatibility options which an administrator might
2581 reasonably wish to set. Interpret a list similarly to decode_bits(), so that
2582 we look like log_selector.
2583
2584 Arguments:
2585 option_spec the administrator-supplied string of options
2586 results ptr to long storage for the options bitmap
2587 Returns success or failure
2588 */
2589
2590 BOOL
2591 tls_openssl_options_parse(uschar *option_spec, long *results)
2592 {
2593 long result, item;
2594 uschar *s, *end;
2595 uschar keep_c;
2596 BOOL adding, item_parsed;
2597
2598 result = 0L;
2599 /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
2600 * from default because it increases BEAST susceptibility. */
2601 #ifdef SSL_OP_NO_SSLv2
2602 result |= SSL_OP_NO_SSLv2;
2603 #endif
2604
2605 if (option_spec == NULL)
2606 {
2607 *results = result;
2608 return TRUE;
2609 }
2610
2611 for (s=option_spec; *s != '\0'; /**/)
2612 {
2613 while (isspace(*s)) ++s;
2614 if (*s == '\0')
2615 break;
2616 if (*s != '+' && *s != '-')
2617 {
2618 DEBUG(D_tls) debug_printf("malformed openssl option setting: "
2619 "+ or - expected but found \"%s\"\n", s);
2620 return FALSE;
2621 }
2622 adding = *s++ == '+';
2623 for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ;
2624 keep_c = *end;
2625 *end = '\0';
2626 item_parsed = tls_openssl_one_option_parse(s, &item);
2627 if (!item_parsed)
2628 {
2629 DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s);
2630 return FALSE;
2631 }
2632 DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n",
2633 adding ? "adding" : "removing", result, item, s);
2634 if (adding)
2635 result |= item;
2636 else
2637 result &= ~item;
2638 *end = keep_c;
2639 s = end;
2640 }
2641
2642 *results = result;
2643 return TRUE;
2644 }
2645
2646 /* vi: aw ai sw=2
2647 */
2648 /* End of tls-openssl.c */
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