Support transport hosts_avoid_tls for cutthrough.
[exim.git] / src / src / tls-openssl.c
CommitLineData
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
c4ceed07 5/* Copyright (c) University of Cambridge 1995 - 2012 */
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6/* See the file NOTICE for conditions of use and distribution. */
7
8/* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
9library. It is #included into the tls.c file when that library is used. The
10code herein is based on a patch that was originally contributed by Steve
11Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara.
12
13No cryptographic code is included in Exim. All this module does is to call
14functions from the OpenSSL library. */
15
16
17/* Heading stuff */
18
19#include <openssl/lhash.h>
20#include <openssl/ssl.h>
21#include <openssl/err.h>
22#include <openssl/rand.h>
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23#ifdef EXPERIMENTAL_OCSP
24#include <openssl/ocsp.h>
25#endif
26
27#ifdef EXPERIMENTAL_OCSP
28#define EXIM_OCSP_SKEW_SECONDS (300L)
29#define EXIM_OCSP_MAX_AGE (-1L)
30#endif
059ec3d9 31
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32#if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
33#define EXIM_HAVE_OPENSSL_TLSEXT
34#endif
35
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36/* Structure for collecting random data for seeding. */
37
38typedef struct randstuff {
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39 struct timeval tv;
40 pid_t p;
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41} randstuff;
42
43/* Local static variables */
44
45static BOOL verify_callback_called = FALSE;
46static const uschar *sid_ctx = US"exim";
47
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48static SSL_CTX *client_ctx = NULL;
49static SSL_CTX *server_ctx = NULL;
50static SSL *client_ssl = NULL;
51static SSL *server_ssl = NULL;
35731706 52#ifdef EXIM_HAVE_OPENSSL_TLSEXT
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53static SSL_CTX *client_sni = NULL;
54static SSL_CTX *server_sni = NULL;
35731706 55#endif
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56
57static char ssl_errstring[256];
58
59static int ssl_session_timeout = 200;
60static BOOL verify_optional = FALSE;
61
7be682ca 62static BOOL reexpand_tls_files_for_sni = FALSE;
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63
64
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65typedef struct tls_ext_ctx_cb {
66 uschar *certificate;
67 uschar *privatekey;
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68#ifdef EXPERIMENTAL_OCSP
69 uschar *ocsp_file;
70 uschar *ocsp_file_expanded;
71 OCSP_RESPONSE *ocsp_response;
72#endif
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73 uschar *dhparam;
74 /* these are cached from first expand */
75 uschar *server_cipher_list;
76 /* only passed down to tls_error: */
77 host_item *host;
78} tls_ext_ctx_cb;
79
80/* should figure out a cleanup of API to handle state preserved per
81implementation, for various reasons, which can be void * in the APIs.
82For now, we hack around it. */
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83tls_ext_ctx_cb *client_static_cbinfo = NULL;
84tls_ext_ctx_cb *server_static_cbinfo = NULL;
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85
86static int
87setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional);
059ec3d9 88
3f7eeb86 89/* Callbacks */
3bcbbbe2 90#ifdef EXIM_HAVE_OPENSSL_TLSEXT
3f7eeb86 91static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg);
3bcbbbe2 92#endif
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93#ifdef EXPERIMENTAL_OCSP
94static int tls_stapling_cb(SSL *s, void *arg);
95#endif
96
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97
98/*************************************************
99* Handle TLS error *
100*************************************************/
101
102/* Called from lots of places when errors occur before actually starting to do
103the TLS handshake, that is, while the session is still in clear. Always returns
104DEFER for a server and FAIL for a client so that most calls can use "return
105tls_error(...)" to do this processing and then give an appropriate return. A
106single function is used for both server and client, because it is called from
107some shared functions.
108
109Argument:
110 prefix text to include in the logged error
111 host NULL if setting up a server;
112 the connected host if setting up a client
7199e1ee 113 msg error message or NULL if we should ask OpenSSL
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114
115Returns: OK/DEFER/FAIL
116*/
117
118static int
7199e1ee 119tls_error(uschar *prefix, host_item *host, uschar *msg)
059ec3d9 120{
7199e1ee
TF
121if (msg == NULL)
122 {
123 ERR_error_string(ERR_get_error(), ssl_errstring);
5ca6d115 124 msg = (uschar *)ssl_errstring;
7199e1ee
TF
125 }
126
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127if (host == NULL)
128 {
7199e1ee 129 uschar *conn_info = smtp_get_connection_info();
5ca6d115 130 if (Ustrncmp(conn_info, US"SMTP ", 5) == 0)
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131 conn_info += 5;
132 log_write(0, LOG_MAIN, "TLS error on %s (%s): %s",
133 conn_info, prefix, msg);
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134 return DEFER;
135 }
136else
137 {
138 log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s",
7199e1ee 139 host->name, host->address, prefix, msg);
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140 return FAIL;
141 }
142}
143
144
145
146/*************************************************
147* Callback to generate RSA key *
148*************************************************/
149
150/*
151Arguments:
152 s SSL connection
153 export not used
154 keylength keylength
155
156Returns: pointer to generated key
157*/
158
159static RSA *
160rsa_callback(SSL *s, int export, int keylength)
161{
162RSA *rsa_key;
163export = export; /* Shut picky compilers up */
164DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength);
165rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL);
166if (rsa_key == NULL)
167 {
168 ERR_error_string(ERR_get_error(), ssl_errstring);
169 log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s",
170 ssl_errstring);
171 return NULL;
172 }
173return rsa_key;
174}
175
176
177
178
179/*************************************************
180* Callback for verification *
181*************************************************/
182
183/* The SSL library does certificate verification if set up to do so. This
184callback has the current yes/no state is in "state". If verification succeeded,
185we set up the tls_peerdn string. If verification failed, what happens depends
186on whether the client is required to present a verifiable certificate or not.
187
188If verification is optional, we change the state to yes, but still log the
189verification error. For some reason (it really would help to have proper
190documentation of OpenSSL), this callback function then gets called again, this
191time with state = 1. In fact, that's useful, because we can set up the peerdn
192value, but we must take care not to set the private verified flag on the second
193time through.
194
195Note: this function is not called if the client fails to present a certificate
196when asked. We get here only if a certificate has been received. Handling of
197optional verification for this case is done when requesting SSL to verify, by
198setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case.
199
200Arguments:
201 state current yes/no state as 1/0
202 x509ctx certificate information.
203
204Returns: 1 if verified, 0 if not
205*/
206
207static int
208verify_callback(int state, X509_STORE_CTX *x509ctx)
209{
210static uschar txt[256];
211
212X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert),
213 CS txt, sizeof(txt));
214
215if (state == 0)
216 {
217 log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s",
218 x509ctx->error_depth,
219 X509_verify_cert_error_string(x509ctx->error),
220 txt);
817d9f57 221 tls_in.certificate_verified = FALSE;
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222 verify_callback_called = TRUE;
223 if (!verify_optional) return 0; /* reject */
224 DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
225 "tls_try_verify_hosts)\n");
226 return 1; /* accept */
227 }
228
229if (x509ctx->error_depth != 0)
230 {
231 DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n",
232 x509ctx->error_depth, txt);
233 }
234else
235 {
236 DEBUG(D_tls) debug_printf("SSL%s peer: %s\n",
237 verify_callback_called? "" : " authenticated", txt);
817d9f57 238 tls_in.peerdn = txt;
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239 }
240
817d9f57 241if (!verify_callback_called) tls_in.certificate_verified = TRUE;
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242verify_callback_called = TRUE;
243
244return 1; /* accept */
245}
246
247
248
249/*************************************************
250* Information callback *
251*************************************************/
252
253/* The SSL library functions call this from time to time to indicate what they
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254are doing. We copy the string to the debugging output when TLS debugging has
255been requested.
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256
257Arguments:
258 s the SSL connection
259 where
260 ret
261
262Returns: nothing
263*/
264
265static void
266info_callback(SSL *s, int where, int ret)
267{
268where = where;
269ret = ret;
270DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s));
271}
272
273
274
275/*************************************************
276* Initialize for DH *
277*************************************************/
278
279/* If dhparam is set, expand it, and load up the parameters for DH encryption.
280
281Arguments:
a799883d 282 dhparam DH parameter file or fixed parameter identity string
7199e1ee 283 host connected host, if client; NULL if server
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284
285Returns: TRUE if OK (nothing to set up, or setup worked)
286*/
287
288static BOOL
817d9f57 289<<<<<<< HEAD
a799883d 290init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host)
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291=======
292init_dh(SSL_CTX *ctx, uschar *dhparam, host_item *host)
293>>>>>>> Dual-tls - split management of TLS into in- and out-bound connection-handling.
059ec3d9 294{
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295BIO *bio;
296DH *dh;
297uschar *dhexpanded;
a799883d 298const char *pem;
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299
300if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded))
301 return FALSE;
302
a799883d 303if (dhexpanded == NULL || *dhexpanded == '\0')
059ec3d9 304 {
a799883d 305 bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1);
059ec3d9 306 }
a799883d 307else if (dhexpanded[0] == '/')
059ec3d9 308 {
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309 bio = BIO_new_file(CS dhexpanded, "r");
310 if (bio == NULL)
059ec3d9 311 {
7199e1ee 312 tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
a799883d
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313 host, US strerror(errno));
314 return FALSE;
059ec3d9 315 }
a799883d
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316 }
317else
318 {
319 if (Ustrcmp(dhexpanded, "none") == 0)
059ec3d9 320 {
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321 DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
322 return TRUE;
059ec3d9 323 }
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324
325 pem = std_dh_prime_named(dhexpanded);
326 if (!pem)
327 {
328 tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded),
329 host, US strerror(errno));
330 return FALSE;
331 }
332 bio = BIO_new_mem_buf(CS pem, -1);
333 }
334
335dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
336if (dh == NULL)
337 {
059ec3d9 338 BIO_free(bio);
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339 tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded),
340 host, NULL);
341 return FALSE;
342 }
343
344/* Even if it is larger, we silently return success rather than cause things
345 * to fail out, so that a too-large DH will not knock out all TLS; it's a
346 * debatable choice. */
347if ((8*DH_size(dh)) > tls_dh_max_bits)
348 {
349 DEBUG(D_tls)
350 debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d",
351 8*DH_size(dh), tls_dh_max_bits);
352 }
353else
354 {
355 SSL_CTX_set_tmp_dh(sctx, dh);
356 DEBUG(D_tls)
357 debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n",
358 dhexpanded ? dhexpanded : US"default", 8*DH_size(dh));
059ec3d9
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359 }
360
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361DH_free(dh);
362BIO_free(bio);
363
364return TRUE;
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365}
366
367
368
369
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370#ifdef EXPERIMENTAL_OCSP
371/*************************************************
372* Load OCSP information into state *
373*************************************************/
374
375/* Called to load the OCSP response from the given file into memory, once
376caller has determined this is needed. Checks validity. Debugs a message
377if invalid.
378
379ASSUMES: single response, for single cert.
380
381Arguments:
382 sctx the SSL_CTX* to update
383 cbinfo various parts of session state
384 expanded the filename putatively holding an OCSP response
385
386*/
387
388static void
389ocsp_load_response(SSL_CTX *sctx,
390 tls_ext_ctx_cb *cbinfo,
391 const uschar *expanded)
392{
393BIO *bio;
394OCSP_RESPONSE *resp;
395OCSP_BASICRESP *basic_response;
396OCSP_SINGLERESP *single_response;
397ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd;
398X509_STORE *store;
399unsigned long verify_flags;
400int status, reason, i;
401
402cbinfo->ocsp_file_expanded = string_copy(expanded);
403if (cbinfo->ocsp_response)
404 {
405 OCSP_RESPONSE_free(cbinfo->ocsp_response);
406 cbinfo->ocsp_response = NULL;
407 }
408
409bio = BIO_new_file(CS cbinfo->ocsp_file_expanded, "rb");
410if (!bio)
411 {
412 DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n",
413 cbinfo->ocsp_file_expanded);
414 return;
415 }
416
417resp = d2i_OCSP_RESPONSE_bio(bio, NULL);
418BIO_free(bio);
419if (!resp)
420 {
421 DEBUG(D_tls) debug_printf("Error reading OCSP response.\n");
422 return;
423 }
424
425status = OCSP_response_status(resp);
426if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL)
427 {
428 DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n",
429 OCSP_response_status_str(status), status);
430 return;
431 }
432
433basic_response = OCSP_response_get1_basic(resp);
434if (!basic_response)
435 {
436 DEBUG(D_tls)
437 debug_printf("OCSP response parse error: unable to extract basic response.\n");
438 return;
439 }
440
441store = SSL_CTX_get_cert_store(sctx);
442verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */
443
444/* May need to expose ability to adjust those flags?
445OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT
446OCSP_TRUSTOTHER OCSP_NOINTERN */
447
448i = OCSP_basic_verify(basic_response, NULL, store, verify_flags);
449if (i <= 0)
450 {
451 DEBUG(D_tls) {
452 ERR_error_string(ERR_get_error(), ssl_errstring);
453 debug_printf("OCSP response verify failure: %s\n", US ssl_errstring);
454 }
455 return;
456 }
457
458/* Here's the simplifying assumption: there's only one response, for the
459one certificate we use, and nothing for anything else in a chain. If this
460proves false, we need to extract a cert id from our issued cert
461(tls_certificate) and use that for OCSP_resp_find_status() (which finds the
462right cert in the stack and then calls OCSP_single_get0_status()).
463
464I'm hoping to avoid reworking a bunch more of how we handle state here. */
465single_response = OCSP_resp_get0(basic_response, 0);
466if (!single_response)
467 {
468 DEBUG(D_tls)
469 debug_printf("Unable to get first response from OCSP basic response.\n");
470 return;
471 }
472
473status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd);
474/* how does this status differ from the one above? */
475if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL)
476 {
477 DEBUG(D_tls) debug_printf("OCSP response not valid (take 2): %s (%d)\n",
478 OCSP_response_status_str(status), status);
479 return;
480 }
481
482if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
483 {
484 DEBUG(D_tls) debug_printf("OCSP status invalid times.\n");
485 return;
486 }
487
488cbinfo->ocsp_response = resp;
489}
490#endif
491
492
493
494
059ec3d9 495/*************************************************
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496* Expand key and cert file specs *
497*************************************************/
498
499/* Called once during tls_init and possibly againt during TLS setup, for a
500new context, if Server Name Indication was used and tls_sni was seen in
501the certificate string.
502
503Arguments:
504 sctx the SSL_CTX* to update
505 cbinfo various parts of session state
506
507Returns: OK/DEFER/FAIL
508*/
509
510static int
3f7eeb86 511tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo)
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512{
513uschar *expanded;
514
515if (cbinfo->certificate == NULL)
516 return OK;
517
518if (Ustrstr(cbinfo->certificate, US"tls_sni"))
519 reexpand_tls_files_for_sni = TRUE;
520
521if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded))
522 return DEFER;
523
524if (expanded != NULL)
525 {
526 DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded);
527 if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded))
528 return tls_error(string_sprintf(
529 "SSL_CTX_use_certificate_chain_file file=%s", expanded),
530 cbinfo->host, NULL);
531 }
532
533if (cbinfo->privatekey != NULL &&
534 !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded))
535 return DEFER;
536
537/* If expansion was forced to fail, key_expanded will be NULL. If the result
538of the expansion is an empty string, ignore it also, and assume the private
539key is in the same file as the certificate. */
540
541if (expanded != NULL && *expanded != 0)
542 {
543 DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded);
544 if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM))
545 return tls_error(string_sprintf(
546 "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL);
547 }
548
3f7eeb86
PP
549#ifdef EXPERIMENTAL_OCSP
550if (cbinfo->ocsp_file != NULL)
551 {
552 if (!expand_check(cbinfo->ocsp_file, US"tls_ocsp_file", &expanded))
553 return DEFER;
554
555 if (expanded != NULL && *expanded != 0)
556 {
557 DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded);
558 if (cbinfo->ocsp_file_expanded &&
559 (Ustrcmp(expanded, cbinfo->ocsp_file_expanded) == 0))
560 {
561 DEBUG(D_tls)
562 debug_printf("tls_ocsp_file value unchanged, using existing values.\n");
563 } else {
564 ocsp_load_response(sctx, cbinfo, expanded);
565 }
566 }
567 }
568#endif
569
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PP
570return OK;
571}
572
573
574
575
576/*************************************************
577* Callback to handle SNI *
578*************************************************/
579
580/* Called when acting as server during the TLS session setup if a Server Name
581Indication extension was sent by the client.
582
583API documentation is OpenSSL s_server.c implementation.
584
585Arguments:
586 s SSL* of the current session
587 ad unknown (part of OpenSSL API) (unused)
588 arg Callback of "our" registered data
589
590Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK}
591*/
592
3bcbbbe2 593#ifdef EXIM_HAVE_OPENSSL_TLSEXT
7be682ca 594static int
7be682ca
PP
595tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg)
596{
597const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
3f7eeb86 598tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
7be682ca 599int rc;
3f0945ff 600int old_pool = store_pool;
7be682ca
PP
601
602if (!servername)
603 return SSL_TLSEXT_ERR_OK;
604
3f0945ff 605DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername,
7be682ca
PP
606 reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)");
607
608/* Make the extension value available for expansion */
3f0945ff 609store_pool = POOL_PERM;
817d9f57 610tls_in.sni = string_copy(US servername);
3f0945ff 611store_pool = old_pool;
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612
613if (!reexpand_tls_files_for_sni)
614 return SSL_TLSEXT_ERR_OK;
615
616/* Can't find an SSL_CTX_clone() or equivalent, so we do it manually;
617not confident that memcpy wouldn't break some internal reference counting.
618Especially since there's a references struct member, which would be off. */
619
817d9f57
JH
620server_sni = SSL_CTX_new(SSLv23_server_method());
621if (!server_sni)
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PP
622 {
623 ERR_error_string(ERR_get_error(), ssl_errstring);
624 DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring);
625 return SSL_TLSEXT_ERR_NOACK;
626 }
627
628/* Not sure how many of these are actually needed, since SSL object
629already exists. Might even need this selfsame callback, for reneg? */
630
817d9f57
JH
631SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx));
632SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx));
633SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx));
634SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx));
635SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
636SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo);
7be682ca 637if (cbinfo->server_cipher_list)
817d9f57 638 SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list);
3f7eeb86
PP
639#ifdef EXPERIMENTAL_OCSP
640if (cbinfo->ocsp_file)
641 {
817d9f57 642 SSL_CTX_set_tlsext_status_cb(server_sni, tls_stapling_cb);
3f7eeb86
PP
643 SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
644 }
645#endif
7be682ca 646
817d9f57 647rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE);
7be682ca
PP
648if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
649
3f7eeb86
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650/* do this after setup_certs, because this can require the certs for verifying
651OCSP information. */
817d9f57 652rc = tls_expand_session_files(server_sni, cbinfo);
7be682ca
PP
653if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
654
a799883d
PP
655rc = init_dh(ctx_sni, cbinfo->dhparam, NULL);
656if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
657
7be682ca 658DEBUG(D_tls) debug_printf("Switching SSL context.\n");
817d9f57 659SSL_set_SSL_CTX(s, server_sni);
7be682ca
PP
660
661return SSL_TLSEXT_ERR_OK;
662}
3bcbbbe2 663#endif /* EXIM_HAVE_OPENSSL_TLSEXT */
7be682ca
PP
664
665
666
667
3f7eeb86
PP
668#ifdef EXPERIMENTAL_OCSP
669/*************************************************
670* Callback to handle OCSP Stapling *
671*************************************************/
672
673/* Called when acting as server during the TLS session setup if the client
674requests OCSP information with a Certificate Status Request.
675
676Documentation via openssl s_server.c and the Apache patch from the OpenSSL
677project.
678
679*/
680
681static int
682tls_stapling_cb(SSL *s, void *arg)
683{
684const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
685uschar *response_der;
686int response_der_len;
687
688DEBUG(D_tls) debug_printf("Received TLS status request (OCSP stapling); %s response.\n",
689 cbinfo->ocsp_response ? "have" : "lack");
690if (!cbinfo->ocsp_response)
691 return SSL_TLSEXT_ERR_NOACK;
692
693response_der = NULL;
694response_der_len = i2d_OCSP_RESPONSE(cbinfo->ocsp_response, &response_der);
695if (response_der_len <= 0)
696 return SSL_TLSEXT_ERR_NOACK;
697
698SSL_set_tlsext_status_ocsp_resp(ssl, response_der, response_der_len);
699return SSL_TLSEXT_ERR_OK;
700}
701
702#endif /* EXPERIMENTAL_OCSP */
703
704
705
706
7be682ca 707/*************************************************
059ec3d9
PH
708* Initialize for TLS *
709*************************************************/
710
711/* Called from both server and client code, to do preliminary initialization of
712the library.
713
714Arguments:
715 host connected host, if client; NULL if server
716 dhparam DH parameter file
717 certificate certificate file
718 privatekey private key
719 addr address if client; NULL if server (for some randomness)
720
721Returns: OK/DEFER/FAIL
722*/
723
724static int
817d9f57 725tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate,
3f7eeb86
PP
726 uschar *privatekey,
727#ifdef EXPERIMENTAL_OCSP
728 uschar *ocsp_file,
729#endif
817d9f57 730 address_item *addr, tls_ext_ctx_cb ** cbp)
059ec3d9 731{
77bb000f 732long init_options;
7be682ca 733int rc;
77bb000f 734BOOL okay;
7be682ca
PP
735tls_ext_ctx_cb *cbinfo;
736
737cbinfo = store_malloc(sizeof(tls_ext_ctx_cb));
738cbinfo->certificate = certificate;
739cbinfo->privatekey = privatekey;
3f7eeb86
PP
740#ifdef EXPERIMENTAL_OCSP
741cbinfo->ocsp_file = ocsp_file;
742#endif
7be682ca
PP
743cbinfo->dhparam = dhparam;
744cbinfo->host = host;
77bb000f 745
059ec3d9
PH
746SSL_load_error_strings(); /* basic set up */
747OpenSSL_add_ssl_algorithms();
748
388d6564 749#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
77bb000f 750/* SHA256 is becoming ever more popular. This makes sure it gets added to the
a0475b69
TK
751list of available digests. */
752EVP_add_digest(EVP_sha256());
cf1ef1a9 753#endif
a0475b69 754
f0f5a555
PP
755/* Create a context.
756The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant
757negotiation in the different methods; as far as I can tell, the only
758*_{server,client}_method which allows negotiation is SSLv23, which exists even
759when OpenSSL is built without SSLv2 support.
760By disabling with openssl_options, we can let admins re-enable with the
761existing knob. */
059ec3d9 762
817d9f57 763*ctxp = SSL_CTX_new((host == NULL)?
059ec3d9
PH
764 SSLv23_server_method() : SSLv23_client_method());
765
817d9f57 766if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL);
059ec3d9
PH
767
768/* It turns out that we need to seed the random number generator this early in
769order to get the full complement of ciphers to work. It took me roughly a day
770of work to discover this by experiment.
771
772On systems that have /dev/urandom, SSL may automatically seed itself from
773there. Otherwise, we have to make something up as best we can. Double check
774afterwards. */
775
776if (!RAND_status())
777 {
778 randstuff r;
9e3331ea 779 gettimeofday(&r.tv, NULL);
059ec3d9
PH
780 r.p = getpid();
781
782 RAND_seed((uschar *)(&r), sizeof(r));
783 RAND_seed((uschar *)big_buffer, big_buffer_size);
784 if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr));
785
786 if (!RAND_status())
7199e1ee 787 return tls_error(US"RAND_status", host,
5ca6d115 788 US"unable to seed random number generator");
059ec3d9
PH
789 }
790
791/* Set up the information callback, which outputs if debugging is at a suitable
792level. */
793
817d9f57 794SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback);
059ec3d9 795
c80c5570 796/* Automatically re-try reads/writes after renegotiation. */
817d9f57 797(void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY);
c80c5570 798
77bb000f
PP
799/* Apply administrator-supplied work-arounds.
800Historically we applied just one requested option,
801SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we
802moved to an administrator-controlled list of options to specify and
803grandfathered in the first one as the default value for "openssl_options".
059ec3d9 804
77bb000f
PP
805No OpenSSL version number checks: the options we accept depend upon the
806availability of the option value macros from OpenSSL. */
059ec3d9 807
77bb000f
PP
808okay = tls_openssl_options_parse(openssl_options, &init_options);
809if (!okay)
73a46702 810 return tls_error(US"openssl_options parsing failed", host, NULL);
77bb000f
PP
811
812if (init_options)
813 {
814 DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options);
817d9f57 815 if (!(SSL_CTX_set_options(*ctxp, init_options)))
77bb000f
PP
816 return tls_error(string_sprintf(
817 "SSL_CTX_set_option(%#lx)", init_options), host, NULL);
818 }
819else
820 DEBUG(D_tls) debug_printf("no SSL CTX options to set\n");
059ec3d9
PH
821
822/* Initialize with DH parameters if supplied */
823
817d9f57 824<<<<<<< HEAD
a799883d 825if (!init_dh(ctx, dhparam, host)) return DEFER;
817d9f57
JH
826=======
827if (!init_dh(*ctxp, dhparam, host)) return DEFER;
828>>>>>>> Dual-tls - split management of TLS into in- and out-bound connection-handling.
059ec3d9 829
3f7eeb86 830/* Set up certificate and key (and perhaps OCSP info) */
059ec3d9 831
817d9f57 832rc = tls_expand_session_files(*ctxp, cbinfo);
7be682ca 833if (rc != OK) return rc;
c91535f3 834
7be682ca 835/* If we need to handle SNI, do so */
3bcbbbe2 836#ifdef EXIM_HAVE_OPENSSL_TLSEXT
3f0945ff
PP
837if (host == NULL)
838 {
3f7eeb86
PP
839#ifdef EXPERIMENTAL_OCSP
840 /* We check ocsp_file, not ocsp_response, because we care about if
841 the option exists, not what the current expansion might be, as SNI might
842 change the certificate and OCSP file in use between now and the time the
843 callback is invoked. */
844 if (cbinfo->ocsp_file)
845 {
846 SSL_CTX_set_tlsext_status_cb(ctx, tls_stapling_cb);
847 SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
848 }
849#endif
3f0945ff
PP
850 /* We always do this, so that $tls_sni is available even if not used in
851 tls_certificate */
817d9f57
JH
852 SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb);
853 SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo);
3f0945ff 854 }
7be682ca 855#endif
059ec3d9
PH
856
857/* Set up the RSA callback */
858
817d9f57 859SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback);
059ec3d9
PH
860
861/* Finally, set the timeout, and we are done */
862
817d9f57 863SSL_CTX_set_timeout(*ctxp, ssl_session_timeout);
059ec3d9 864DEBUG(D_tls) debug_printf("Initialized TLS\n");
7be682ca 865
817d9f57 866*cbp = cbinfo;
7be682ca 867
059ec3d9
PH
868return OK;
869}
870
871
872
873
874/*************************************************
875* Get name of cipher in use *
876*************************************************/
877
817d9f57 878/*
059ec3d9 879Argument: pointer to an SSL structure for the connection
817d9f57
JH
880 buffer to use for answer
881 size of buffer
882 pointer to number of bits for cipher
059ec3d9
PH
883Returns: nothing
884*/
885
886static void
817d9f57 887construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits)
059ec3d9 888{
57b3a7f5
PP
889/* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't
890yet reflect that. It should be a safe change anyway, even 0.9.8 versions have
891the accessor functions use const in the prototype. */
892const SSL_CIPHER *c;
059ec3d9 893uschar *ver;
059ec3d9
PH
894
895switch (ssl->session->ssl_version)
896 {
897 case SSL2_VERSION:
898 ver = US"SSLv2";
899 break;
900
901 case SSL3_VERSION:
902 ver = US"SSLv3";
903 break;
904
905 case TLS1_VERSION:
906 ver = US"TLSv1";
907 break;
908
c80c5570
PP
909#ifdef TLS1_1_VERSION
910 case TLS1_1_VERSION:
911 ver = US"TLSv1.1";
912 break;
913#endif
914
915#ifdef TLS1_2_VERSION
916 case TLS1_2_VERSION:
917 ver = US"TLSv1.2";
918 break;
919#endif
920
059ec3d9
PH
921 default:
922 ver = US"UNKNOWN";
923 }
924
57b3a7f5 925c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl);
817d9f57 926SSL_CIPHER_get_bits(c, bits);
059ec3d9 927
817d9f57
JH
928string_format(cipherbuf, bsize, "%s:%s:%u", ver,
929 SSL_CIPHER_get_name(c), *bits);
059ec3d9
PH
930
931DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf);
932}
933
934
935
936
937
938/*************************************************
939* Set up for verifying certificates *
940*************************************************/
941
942/* Called by both client and server startup
943
944Arguments:
7be682ca 945 sctx SSL_CTX* to initialise
059ec3d9
PH
946 certs certs file or NULL
947 crl CRL file or NULL
948 host NULL in a server; the remote host in a client
949 optional TRUE if called from a server for a host in tls_try_verify_hosts;
950 otherwise passed as FALSE
951
952Returns: OK/DEFER/FAIL
953*/
954
955static int
7be682ca 956setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional)
059ec3d9
PH
957{
958uschar *expcerts, *expcrl;
959
960if (!expand_check(certs, US"tls_verify_certificates", &expcerts))
961 return DEFER;
962
963if (expcerts != NULL)
964 {
965 struct stat statbuf;
7be682ca 966 if (!SSL_CTX_set_default_verify_paths(sctx))
7199e1ee 967 return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL);
059ec3d9
PH
968
969 if (Ustat(expcerts, &statbuf) < 0)
970 {
971 log_write(0, LOG_MAIN|LOG_PANIC,
972 "failed to stat %s for certificates", expcerts);
973 return DEFER;
974 }
975 else
976 {
977 uschar *file, *dir;
978 if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
979 { file = NULL; dir = expcerts; }
980 else
981 { file = expcerts; dir = NULL; }
982
983 /* If a certificate file is empty, the next function fails with an
984 unhelpful error message. If we skip it, we get the correct behaviour (no
985 certificates are recognized, but the error message is still misleading (it
986 says no certificate was supplied.) But this is better. */
987
988 if ((file == NULL || statbuf.st_size > 0) &&
7be682ca 989 !SSL_CTX_load_verify_locations(sctx, CS file, CS dir))
7199e1ee 990 return tls_error(US"SSL_CTX_load_verify_locations", host, NULL);
059ec3d9
PH
991
992 if (file != NULL)
993 {
7be682ca 994 SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file));
059ec3d9
PH
995 }
996 }
997
998 /* Handle a certificate revocation list. */
999
1000 #if OPENSSL_VERSION_NUMBER > 0x00907000L
1001
8b417f2c
PH
1002 /* This bit of code is now the version supplied by Lars Mainka. (I have
1003 * merely reformatted it into the Exim code style.)
1004
1005 * "From here I changed the code to add support for multiple crl's
1006 * in pem format in one file or to support hashed directory entries in
1007 * pem format instead of a file. This method now uses the library function
1008 * X509_STORE_load_locations to add the CRL location to the SSL context.
1009 * OpenSSL will then handle the verify against CA certs and CRLs by
1010 * itself in the verify callback." */
1011
059ec3d9
PH
1012 if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER;
1013 if (expcrl != NULL && *expcrl != 0)
1014 {
8b417f2c
PH
1015 struct stat statbufcrl;
1016 if (Ustat(expcrl, &statbufcrl) < 0)
1017 {
1018 log_write(0, LOG_MAIN|LOG_PANIC,
1019 "failed to stat %s for certificates revocation lists", expcrl);
1020 return DEFER;
1021 }
1022 else
059ec3d9 1023 {
8b417f2c
PH
1024 /* is it a file or directory? */
1025 uschar *file, *dir;
7be682ca 1026 X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx);
8b417f2c 1027 if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR)
059ec3d9 1028 {
8b417f2c
PH
1029 file = NULL;
1030 dir = expcrl;
1031 DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir);
059ec3d9
PH
1032 }
1033 else
1034 {
8b417f2c
PH
1035 file = expcrl;
1036 dir = NULL;
1037 DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file);
059ec3d9 1038 }
8b417f2c 1039 if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0)
7199e1ee 1040 return tls_error(US"X509_STORE_load_locations", host, NULL);
8b417f2c
PH
1041
1042 /* setting the flags to check against the complete crl chain */
1043
1044 X509_STORE_set_flags(cvstore,
1045 X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
059ec3d9 1046 }
059ec3d9
PH
1047 }
1048
1049 #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
1050
1051 /* If verification is optional, don't fail if no certificate */
1052
7be682ca 1053 SSL_CTX_set_verify(sctx,
059ec3d9
PH
1054 SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT),
1055 verify_callback);
1056 }
1057
1058return OK;
1059}
1060
1061
1062
1063/*************************************************
1064* Start a TLS session in a server *
1065*************************************************/
1066
1067/* This is called when Exim is running as a server, after having received
1068the STARTTLS command. It must respond to that command, and then negotiate
1069a TLS session.
1070
1071Arguments:
1072 require_ciphers allowed ciphers
1073
1074Returns: OK on success
1075 DEFER for errors before the start of the negotiation
1076 FAIL for errors during the negotation; the server can't
1077 continue running.
1078*/
1079
1080int
17c76198 1081tls_server_start(const uschar *require_ciphers)
059ec3d9
PH
1082{
1083int rc;
1084uschar *expciphers;
7be682ca 1085tls_ext_ctx_cb *cbinfo;
817d9f57 1086static uschar cipherbuf[256];
059ec3d9
PH
1087
1088/* Check for previous activation */
1089
817d9f57 1090if (tls_in.active >= 0)
059ec3d9 1091 {
5ca6d115 1092 tls_error(US"STARTTLS received after TLS started", NULL, US"");
059ec3d9
PH
1093 smtp_printf("554 Already in TLS\r\n");
1094 return FAIL;
1095 }
1096
1097/* Initialize the SSL library. If it fails, it will already have logged
1098the error. */
1099
817d9f57 1100rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey,
3f7eeb86
PP
1101#ifdef EXPERIMENTAL_OCSP
1102 tls_ocsp_file,
1103#endif
817d9f57 1104 NULL, &server_static_cbinfo);
059ec3d9 1105if (rc != OK) return rc;
817d9f57 1106cbinfo = server_static_cbinfo;
059ec3d9
PH
1107
1108if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers))
1109 return FAIL;
1110
1111/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
17c76198
PP
1112were historically separated by underscores. So that I can use either form in my
1113tests, and also for general convenience, we turn underscores into hyphens here.
1114*/
059ec3d9
PH
1115
1116if (expciphers != NULL)
1117 {
1118 uschar *s = expciphers;
1119 while (*s != 0) { if (*s == '_') *s = '-'; s++; }
1120 DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
817d9f57 1121 if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers))
7199e1ee 1122 return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL);
7be682ca 1123 cbinfo->server_cipher_list = expciphers;
059ec3d9
PH
1124 }
1125
1126/* If this is a host for which certificate verification is mandatory or
1127optional, set up appropriately. */
1128
817d9f57 1129tls_in.certificate_verified = FALSE;
059ec3d9
PH
1130verify_callback_called = FALSE;
1131
1132if (verify_check_host(&tls_verify_hosts) == OK)
1133 {
817d9f57 1134 rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, FALSE);
059ec3d9
PH
1135 if (rc != OK) return rc;
1136 verify_optional = FALSE;
1137 }
1138else if (verify_check_host(&tls_try_verify_hosts) == OK)
1139 {
817d9f57 1140 rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, TRUE);
059ec3d9
PH
1141 if (rc != OK) return rc;
1142 verify_optional = TRUE;
1143 }
1144
1145/* Prepare for new connection */
1146
817d9f57 1147if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL);
da3ad30d
PP
1148
1149/* Warning: we used to SSL_clear(ssl) here, it was removed.
1150 *
1151 * With the SSL_clear(), we get strange interoperability bugs with
1152 * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in
1153 * OpenSSL itself, as a clear should not lead to inability to follow protocols.
1154 *
1155 * The SSL_clear() call is to let an existing SSL* be reused, typically after
1156 * session shutdown. In this case, we have a brand new object and there's no
1157 * obvious reason to immediately clear it. I'm guessing that this was
1158 * originally added because of incomplete initialisation which the clear fixed,
1159 * in some historic release.
1160 */
059ec3d9
PH
1161
1162/* Set context and tell client to go ahead, except in the case of TLS startup
1163on connection, where outputting anything now upsets the clients and tends to
1164make them disconnect. We need to have an explicit fflush() here, to force out
1165the response. Other smtp_printf() calls do not need it, because in non-TLS
1166mode, the fflush() happens when smtp_getc() is called. */
1167
817d9f57
JH
1168SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx));
1169if (!tls_in.on_connect)
059ec3d9
PH
1170 {
1171 smtp_printf("220 TLS go ahead\r\n");
1172 fflush(smtp_out);
1173 }
1174
1175/* Now negotiate the TLS session. We put our own timer on it, since it seems
1176that the OpenSSL library doesn't. */
1177
817d9f57
JH
1178SSL_set_wfd(server_ssl, fileno(smtp_out));
1179SSL_set_rfd(server_ssl, fileno(smtp_in));
1180SSL_set_accept_state(server_ssl);
059ec3d9
PH
1181
1182DEBUG(D_tls) debug_printf("Calling SSL_accept\n");
1183
1184sigalrm_seen = FALSE;
1185if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
817d9f57 1186rc = SSL_accept(server_ssl);
059ec3d9
PH
1187alarm(0);
1188
1189if (rc <= 0)
1190 {
7199e1ee 1191 tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL);
77bb000f
PP
1192 if (ERR_get_error() == 0)
1193 log_write(0, LOG_MAIN,
a053d125 1194 "TLS client disconnected cleanly (rejected our certificate?)");
059ec3d9
PH
1195 return FAIL;
1196 }
1197
1198DEBUG(D_tls) debug_printf("SSL_accept was successful\n");
1199
1200/* TLS has been set up. Adjust the input functions to read via TLS,
1201and initialize things. */
1202
817d9f57
JH
1203construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits);
1204tls_in.cipher = cipherbuf;
059ec3d9
PH
1205
1206DEBUG(D_tls)
1207 {
1208 uschar buf[2048];
817d9f57 1209 if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL)
059ec3d9
PH
1210 debug_printf("Shared ciphers: %s\n", buf);
1211 }
1212
1213
817d9f57
JH
1214/* Only used by the server-side tls (tls_in), including tls_getc.
1215 Client-side (tls_out) reads (seem to?) go via
1216 smtp_read_response()/ip_recv().
1217 Hence no need to duplicate for _in and _out.
1218 */
059ec3d9
PH
1219ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size);
1220ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0;
1221ssl_xfer_eof = ssl_xfer_error = 0;
1222
1223receive_getc = tls_getc;
1224receive_ungetc = tls_ungetc;
1225receive_feof = tls_feof;
1226receive_ferror = tls_ferror;
58eb016e 1227receive_smtp_buffered = tls_smtp_buffered;
059ec3d9 1228
817d9f57 1229tls_in.active = fileno(smtp_out);
059ec3d9
PH
1230return OK;
1231}
1232
1233
1234
1235
1236
1237/*************************************************
1238* Start a TLS session in a client *
1239*************************************************/
1240
1241/* Called from the smtp transport after STARTTLS has been accepted.
1242
1243Argument:
1244 fd the fd of the connection
1245 host connected host (for messages)
83da1223 1246 addr the first address
059ec3d9
PH
1247 dhparam DH parameter file
1248 certificate certificate file
1249 privatekey private key file
3f0945ff 1250 sni TLS SNI to send to remote host
059ec3d9
PH
1251 verify_certs file for certificate verify
1252 crl file containing CRL
1253 require_ciphers list of allowed ciphers
54c90be1
PP
1254 dh_min_bits minimum number of bits acceptable in server's DH prime
1255 (unused in OpenSSL)
83da1223 1256 timeout startup timeout
059ec3d9
PH
1257
1258Returns: OK on success
1259 FAIL otherwise - note that tls_error() will not give DEFER
1260 because this is not a server
1261*/
1262
1263int
1264tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam,
3f0945ff
PP
1265 uschar *certificate, uschar *privatekey, uschar *sni,
1266 uschar *verify_certs, uschar *crl,
54c90be1 1267 uschar *require_ciphers, int dh_min_bits ARG_UNUSED, int timeout)
059ec3d9
PH
1268{
1269static uschar txt[256];
1270uschar *expciphers;
1271X509* server_cert;
1272int rc;
817d9f57 1273static uschar cipherbuf[256];
059ec3d9 1274
817d9f57 1275rc = tls_init(&client_ctx, host, dhparam, certificate, privatekey,
3f7eeb86
PP
1276#ifdef EXPERIMENTAL_OCSP
1277 NULL,
1278#endif
817d9f57 1279 addr, &client_static_cbinfo);
059ec3d9
PH
1280if (rc != OK) return rc;
1281
817d9f57 1282tls_out.certificate_verified = FALSE;
059ec3d9
PH
1283verify_callback_called = FALSE;
1284
1285if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers))
1286 return FAIL;
1287
1288/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
1289are separated by underscores. So that I can use either form in my tests, and
1290also for general convenience, we turn underscores into hyphens here. */
1291
1292if (expciphers != NULL)
1293 {
1294 uschar *s = expciphers;
1295 while (*s != 0) { if (*s == '_') *s = '-'; s++; }
1296 DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
817d9f57 1297 if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers))
7199e1ee 1298 return tls_error(US"SSL_CTX_set_cipher_list", host, NULL);
059ec3d9
PH
1299 }
1300
817d9f57 1301rc = setup_certs(client_ctx, verify_certs, crl, host, FALSE);
059ec3d9
PH
1302if (rc != OK) return rc;
1303
817d9f57
JH
1304if ((client_ssl = SSL_new(client_ctx)) == NULL) return tls_error(US"SSL_new", host, NULL);
1305SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx));
1306SSL_set_fd(client_ssl, fd);
1307SSL_set_connect_state(client_ssl);
059ec3d9 1308
3f0945ff
PP
1309if (sni)
1310 {
817d9f57 1311 if (!expand_check(sni, US"tls_sni", &tls_out.sni))
3f0945ff 1312 return FAIL;
817d9f57
JH
1313 if (!Ustrlen(tls_out.sni))
1314 tls_out.sni = NULL;
3f0945ff
PP
1315 else
1316 {
35731706 1317#ifdef EXIM_HAVE_OPENSSL_TLSEXT
817d9f57
JH
1318 DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni);
1319 SSL_set_tlsext_host_name(client_ssl, tls_out.sni);
35731706
PP
1320#else
1321 DEBUG(D_tls)
1322 debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n",
1323 tls_sni);
1324#endif
3f0945ff
PP
1325 }
1326 }
1327
059ec3d9
PH
1328/* There doesn't seem to be a built-in timeout on connection. */
1329
1330DEBUG(D_tls) debug_printf("Calling SSL_connect\n");
1331sigalrm_seen = FALSE;
1332alarm(timeout);
817d9f57 1333rc = SSL_connect(client_ssl);
059ec3d9
PH
1334alarm(0);
1335
1336if (rc <= 0)
7199e1ee 1337 return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL);
059ec3d9
PH
1338
1339DEBUG(D_tls) debug_printf("SSL_connect succeeded\n");
1340
453a6645 1341/* Beware anonymous ciphers which lead to server_cert being NULL */
817d9f57 1342server_cert = SSL_get_peer_certificate (client_ssl);
453a6645
PP
1343if (server_cert)
1344 {
817d9f57 1345 tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert),
453a6645 1346 CS txt, sizeof(txt));
817d9f57 1347 tls_out.peerdn = txt;
453a6645
PP
1348 }
1349else
817d9f57 1350 tls_out.peerdn = NULL;
059ec3d9 1351
817d9f57
JH
1352construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits);
1353tls_out.cipher = cipherbuf;
059ec3d9 1354
817d9f57 1355tls_out.active = fd;
059ec3d9
PH
1356return OK;
1357}
1358
1359
1360
1361
1362
1363/*************************************************
1364* TLS version of getc *
1365*************************************************/
1366
1367/* This gets the next byte from the TLS input buffer. If the buffer is empty,
1368it refills the buffer via the SSL reading function.
1369
1370Arguments: none
1371Returns: the next character or EOF
817d9f57
JH
1372
1373Only used by the server-side TLS.
059ec3d9
PH
1374*/
1375
1376int
1377tls_getc(void)
1378{
1379if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm)
1380 {
1381 int error;
1382 int inbytes;
1383
817d9f57 1384 DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl,
c80c5570 1385 ssl_xfer_buffer, ssl_xfer_buffer_size);
059ec3d9
PH
1386
1387 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
817d9f57
JH
1388 inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size);
1389 error = SSL_get_error(server_ssl, inbytes);
059ec3d9
PH
1390 alarm(0);
1391
1392 /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been
1393 closed down, not that the socket itself has been closed down. Revert to
1394 non-SSL handling. */
1395
1396 if (error == SSL_ERROR_ZERO_RETURN)
1397 {
1398 DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
1399
1400 receive_getc = smtp_getc;
1401 receive_ungetc = smtp_ungetc;
1402 receive_feof = smtp_feof;
1403 receive_ferror = smtp_ferror;
58eb016e 1404 receive_smtp_buffered = smtp_buffered;
059ec3d9 1405
817d9f57
JH
1406 SSL_free(server_ssl);
1407 server_ssl = NULL;
1408 tls_in.active = -1;
1409 tls_in.bits = 0;
1410 tls_in.cipher = NULL;
1411 tls_in.peerdn = NULL;
1412 tls_in.sni = NULL;
059ec3d9
PH
1413
1414 return smtp_getc();
1415 }
1416
1417 /* Handle genuine errors */
1418
ba084640
PP
1419 else if (error == SSL_ERROR_SSL)
1420 {
1421 ERR_error_string(ERR_get_error(), ssl_errstring);
89dd51cd 1422 log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring);
ba084640
PP
1423 ssl_xfer_error = 1;
1424 return EOF;
1425 }
1426
059ec3d9
PH
1427 else if (error != SSL_ERROR_NONE)
1428 {
1429 DEBUG(D_tls) debug_printf("Got SSL error %d\n", error);
1430 ssl_xfer_error = 1;
1431 return EOF;
1432 }
c80c5570 1433
80a47a2c
TK
1434#ifndef DISABLE_DKIM
1435 dkim_exim_verify_feed(ssl_xfer_buffer, inbytes);
1436#endif
059ec3d9
PH
1437 ssl_xfer_buffer_hwm = inbytes;
1438 ssl_xfer_buffer_lwm = 0;
1439 }
1440
1441/* Something in the buffer; return next uschar */
1442
1443return ssl_xfer_buffer[ssl_xfer_buffer_lwm++];
1444}
1445
1446
1447
1448/*************************************************
1449* Read bytes from TLS channel *
1450*************************************************/
1451
1452/*
1453Arguments:
1454 buff buffer of data
1455 len size of buffer
1456
1457Returns: the number of bytes read
1458 -1 after a failed read
817d9f57
JH
1459
1460Only used by the client-side TLS.
059ec3d9
PH
1461*/
1462
1463int
1464tls_read(uschar *buff, size_t len)
1465{
1466int inbytes;
1467int error;
1468
817d9f57 1469DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", client_ssl,
c80c5570 1470 buff, (unsigned int)len);
059ec3d9 1471
817d9f57
JH
1472inbytes = SSL_read(client_ssl, CS buff, len);
1473error = SSL_get_error(client_ssl, inbytes);
059ec3d9
PH
1474
1475if (error == SSL_ERROR_ZERO_RETURN)
1476 {
1477 DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
1478 return -1;
1479 }
1480else if (error != SSL_ERROR_NONE)
1481 {
1482 return -1;
1483 }
1484
1485return inbytes;
1486}
1487
1488
1489
1490
1491
1492/*************************************************
1493* Write bytes down TLS channel *
1494*************************************************/
1495
1496/*
1497Arguments:
817d9f57 1498 is_server channel specifier
059ec3d9
PH
1499 buff buffer of data
1500 len number of bytes
1501
1502Returns: the number of bytes after a successful write,
1503 -1 after a failed write
817d9f57
JH
1504
1505Used by both server-side and client-side TLS.
059ec3d9
PH
1506*/
1507
1508int
817d9f57 1509tls_write(BOOL is_server, const uschar *buff, size_t len)
059ec3d9
PH
1510{
1511int outbytes;
1512int error;
1513int left = len;
817d9f57 1514SSL *ssl = is_server ? server_ssl : client_ssl;
059ec3d9 1515
c80c5570 1516DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left);
059ec3d9
PH
1517while (left > 0)
1518 {
c80c5570 1519 DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left);
059ec3d9
PH
1520 outbytes = SSL_write(ssl, CS buff, left);
1521 error = SSL_get_error(ssl, outbytes);
1522 DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error);
1523 switch (error)
1524 {
1525 case SSL_ERROR_SSL:
1526 ERR_error_string(ERR_get_error(), ssl_errstring);
1527 log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring);
1528 return -1;
1529
1530 case SSL_ERROR_NONE:
1531 left -= outbytes;
1532 buff += outbytes;
1533 break;
1534
1535 case SSL_ERROR_ZERO_RETURN:
1536 log_write(0, LOG_MAIN, "SSL channel closed on write");
1537 return -1;
1538
817d9f57
JH
1539 case SSL_ERROR_SYSCALL:
1540 log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s",
1541 sender_fullhost ? sender_fullhost : US"<unknown>",
1542 strerror(errno));
1543
059ec3d9
PH
1544 default:
1545 log_write(0, LOG_MAIN, "SSL_write error %d", error);
1546 return -1;
1547 }
1548 }
1549return len;
1550}
1551
1552
1553
1554/*************************************************
1555* Close down a TLS session *
1556*************************************************/
1557
1558/* This is also called from within a delivery subprocess forked from the
1559daemon, to shut down the TLS library, without actually doing a shutdown (which
1560would tamper with the SSL session in the parent process).
1561
1562Arguments: TRUE if SSL_shutdown is to be called
1563Returns: nothing
817d9f57
JH
1564
1565Used by both server-side and client-side TLS.
059ec3d9
PH
1566*/
1567
1568void
817d9f57 1569tls_close(BOOL is_server, BOOL shutdown)
059ec3d9 1570{
817d9f57
JH
1571SSL **sslp = is_server ? &server_ssl : &client_ssl;
1572
1573if (*fdp < 0) return; /* TLS was not active */
059ec3d9
PH
1574
1575if (shutdown)
1576 {
1577 DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n");
817d9f57 1578 SSL_shutdown(*sslp);
059ec3d9
PH
1579 }
1580
817d9f57
JH
1581SSL_free(*sslp);
1582*sslp = NULL;
059ec3d9 1583
817d9f57 1584*fdp = -1;
059ec3d9
PH
1585}
1586
36f12725
NM
1587
1588
1589
1590/*************************************************
3375e053
PP
1591* Let tls_require_ciphers be checked at startup *
1592*************************************************/
1593
1594/* The tls_require_ciphers option, if set, must be something which the
1595library can parse.
1596
1597Returns: NULL on success, or error message
1598*/
1599
1600uschar *
1601tls_validate_require_cipher(void)
1602{
1603SSL_CTX *ctx;
1604uschar *s, *expciphers, *err;
1605
1606/* this duplicates from tls_init(), we need a better "init just global
1607state, for no specific purpose" singleton function of our own */
1608
1609SSL_load_error_strings();
1610OpenSSL_add_ssl_algorithms();
1611#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
1612/* SHA256 is becoming ever more popular. This makes sure it gets added to the
1613list of available digests. */
1614EVP_add_digest(EVP_sha256());
1615#endif
1616
1617if (!(tls_require_ciphers && *tls_require_ciphers))
1618 return NULL;
1619
1620if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers))
1621 return US"failed to expand tls_require_ciphers";
1622
1623if (!(expciphers && *expciphers))
1624 return NULL;
1625
1626/* normalisation ripped from above */
1627s = expciphers;
1628while (*s != 0) { if (*s == '_') *s = '-'; s++; }
1629
1630err = NULL;
1631
1632ctx = SSL_CTX_new(SSLv23_server_method());
1633if (!ctx)
1634 {
1635 ERR_error_string(ERR_get_error(), ssl_errstring);
1636 return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring);
1637 }
1638
1639DEBUG(D_tls)
1640 debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);
1641
1642if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
1643 {
1644 ERR_error_string(ERR_get_error(), ssl_errstring);
1645 err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers);
1646 }
1647
1648SSL_CTX_free(ctx);
1649
1650return err;
1651}
1652
1653
1654
1655
1656/*************************************************
36f12725
NM
1657* Report the library versions. *
1658*************************************************/
1659
1660/* There have historically been some issues with binary compatibility in
1661OpenSSL libraries; if Exim (like many other applications) is built against
1662one version of OpenSSL but the run-time linker picks up another version,
1663it can result in serious failures, including crashing with a SIGSEGV. So
1664report the version found by the compiler and the run-time version.
1665
1666Arguments: a FILE* to print the results to
1667Returns: nothing
1668*/
1669
1670void
1671tls_version_report(FILE *f)
1672{
754a0503
PP
1673fprintf(f, "Library version: OpenSSL: Compile: %s\n"
1674 " Runtime: %s\n",
1675 OPENSSL_VERSION_TEXT,
1676 SSLeay_version(SSLEAY_VERSION));
36f12725
NM
1677}
1678
9e3331ea
TK
1679
1680
1681
1682/*************************************************
17c76198 1683* Random number generation *
9e3331ea
TK
1684*************************************************/
1685
1686/* Pseudo-random number generation. The result is not expected to be
1687cryptographically strong but not so weak that someone will shoot themselves
1688in the foot using it as a nonce in input in some email header scheme or
1689whatever weirdness they'll twist this into. The result should handle fork()
1690and avoid repeating sequences. OpenSSL handles that for us.
1691
1692Arguments:
1693 max range maximum
1694Returns a random number in range [0, max-1]
1695*/
1696
1697int
17c76198 1698vaguely_random_number(int max)
9e3331ea
TK
1699{
1700unsigned int r;
1701int i, needed_len;
1702uschar *p;
1703uschar smallbuf[sizeof(r)];
1704
1705if (max <= 1)
1706 return 0;
1707
1708/* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */
1709if (!RAND_status())
1710 {
1711 randstuff r;
1712 gettimeofday(&r.tv, NULL);
1713 r.p = getpid();
1714
1715 RAND_seed((uschar *)(&r), sizeof(r));
1716 }
1717/* We're after pseudo-random, not random; if we still don't have enough data
1718in the internal PRNG then our options are limited. We could sleep and hope
1719for entropy to come along (prayer technique) but if the system is so depleted
1720in the first place then something is likely to just keep taking it. Instead,
1721we'll just take whatever little bit of pseudo-random we can still manage to
1722get. */
1723
1724needed_len = sizeof(r);
1725/* Don't take 8 times more entropy than needed if int is 8 octets and we were
1726asked for a number less than 10. */
1727for (r = max, i = 0; r; ++i)
1728 r >>= 1;
1729i = (i + 7) / 8;
1730if (i < needed_len)
1731 needed_len = i;
1732
1733/* We do not care if crypto-strong */
17c76198
PP
1734i = RAND_pseudo_bytes(smallbuf, needed_len);
1735if (i < 0)
1736 {
1737 DEBUG(D_all)
1738 debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n");
1739 return vaguely_random_number_fallback(max);
1740 }
1741
9e3331ea
TK
1742r = 0;
1743for (p = smallbuf; needed_len; --needed_len, ++p)
1744 {
1745 r *= 256;
1746 r += *p;
1747 }
1748
1749/* We don't particularly care about weighted results; if someone wants
1750smooth distribution and cares enough then they should submit a patch then. */
1751return r % max;
1752}
1753
77bb000f
PP
1754
1755
1756
1757/*************************************************
1758* OpenSSL option parse *
1759*************************************************/
1760
1761/* Parse one option for tls_openssl_options_parse below
1762
1763Arguments:
1764 name one option name
1765 value place to store a value for it
1766Returns success or failure in parsing
1767*/
1768
1769struct exim_openssl_option {
1770 uschar *name;
1771 long value;
1772};
1773/* We could use a macro to expand, but we need the ifdef and not all the
1774options document which version they were introduced in. Policylet: include
1775all options unless explicitly for DTLS, let the administrator choose which
1776to apply.
1777
1778This list is current as of:
c80c5570 1779 ==> 1.0.1b <== */
77bb000f
PP
1780static struct exim_openssl_option exim_openssl_options[] = {
1781/* KEEP SORTED ALPHABETICALLY! */
1782#ifdef SSL_OP_ALL
73a46702 1783 { US"all", SSL_OP_ALL },
77bb000f
PP
1784#endif
1785#ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
73a46702 1786 { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION },
77bb000f
PP
1787#endif
1788#ifdef SSL_OP_CIPHER_SERVER_PREFERENCE
73a46702 1789 { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE },
77bb000f
PP
1790#endif
1791#ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
73a46702 1792 { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS },
77bb000f
PP
1793#endif
1794#ifdef SSL_OP_EPHEMERAL_RSA
73a46702 1795 { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA },
77bb000f
PP
1796#endif
1797#ifdef SSL_OP_LEGACY_SERVER_CONNECT
73a46702 1798 { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT },
77bb000f
PP
1799#endif
1800#ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
73a46702 1801 { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER },
77bb000f
PP
1802#endif
1803#ifdef SSL_OP_MICROSOFT_SESS_ID_BUG
73a46702 1804 { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG },
77bb000f
PP
1805#endif
1806#ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING
73a46702 1807 { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING },
77bb000f
PP
1808#endif
1809#ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG
73a46702 1810 { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG },
77bb000f
PP
1811#endif
1812#ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
73a46702 1813 { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG },
77bb000f 1814#endif
c80c5570
PP
1815#ifdef SSL_OP_NO_COMPRESSION
1816 { US"no_compression", SSL_OP_NO_COMPRESSION },
1817#endif
77bb000f 1818#ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
73a46702 1819 { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION },
77bb000f 1820#endif
c0c7b2da
PP
1821#ifdef SSL_OP_NO_SSLv2
1822 { US"no_sslv2", SSL_OP_NO_SSLv2 },
1823#endif
1824#ifdef SSL_OP_NO_SSLv3
1825 { US"no_sslv3", SSL_OP_NO_SSLv3 },
1826#endif
1827#ifdef SSL_OP_NO_TICKET
1828 { US"no_ticket", SSL_OP_NO_TICKET },
1829#endif
1830#ifdef SSL_OP_NO_TLSv1
1831 { US"no_tlsv1", SSL_OP_NO_TLSv1 },
1832#endif
c80c5570
PP
1833#ifdef SSL_OP_NO_TLSv1_1
1834#if SSL_OP_NO_TLSv1_1 == 0x00000400L
1835 /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */
1836#warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring
1837#else
1838 { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 },
1839#endif
1840#endif
1841#ifdef SSL_OP_NO_TLSv1_2
1842 { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 },
1843#endif
77bb000f 1844#ifdef SSL_OP_SINGLE_DH_USE
73a46702 1845 { US"single_dh_use", SSL_OP_SINGLE_DH_USE },
77bb000f
PP
1846#endif
1847#ifdef SSL_OP_SINGLE_ECDH_USE
73a46702 1848 { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE },
77bb000f
PP
1849#endif
1850#ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG
73a46702 1851 { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG },
77bb000f
PP
1852#endif
1853#ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
73a46702 1854 { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG },
77bb000f
PP
1855#endif
1856#ifdef SSL_OP_TLS_BLOCK_PADDING_BUG
73a46702 1857 { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG },
77bb000f
PP
1858#endif
1859#ifdef SSL_OP_TLS_D5_BUG
73a46702 1860 { US"tls_d5_bug", SSL_OP_TLS_D5_BUG },
77bb000f
PP
1861#endif
1862#ifdef SSL_OP_TLS_ROLLBACK_BUG
73a46702 1863 { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG },
77bb000f
PP
1864#endif
1865};
1866static int exim_openssl_options_size =
1867 sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option);
1868
c80c5570 1869
77bb000f
PP
1870static BOOL
1871tls_openssl_one_option_parse(uschar *name, long *value)
1872{
1873int first = 0;
1874int last = exim_openssl_options_size;
1875while (last > first)
1876 {
1877 int middle = (first + last)/2;
1878 int c = Ustrcmp(name, exim_openssl_options[middle].name);
1879 if (c == 0)
1880 {
1881 *value = exim_openssl_options[middle].value;
1882 return TRUE;
1883 }
1884 else if (c > 0)
1885 first = middle + 1;
1886 else
1887 last = middle;
1888 }
1889return FALSE;
1890}
1891
1892
1893
1894
1895/*************************************************
1896* OpenSSL option parsing logic *
1897*************************************************/
1898
1899/* OpenSSL has a number of compatibility options which an administrator might
1900reasonably wish to set. Interpret a list similarly to decode_bits(), so that
1901we look like log_selector.
1902
1903Arguments:
1904 option_spec the administrator-supplied string of options
1905 results ptr to long storage for the options bitmap
1906Returns success or failure
1907*/
1908
1909BOOL
1910tls_openssl_options_parse(uschar *option_spec, long *results)
1911{
1912long result, item;
1913uschar *s, *end;
1914uschar keep_c;
1915BOOL adding, item_parsed;
1916
0e944a0d 1917result = 0L;
b1770b6e 1918/* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
da3ad30d 1919 * from default because it increases BEAST susceptibility. */
f0f5a555
PP
1920#ifdef SSL_OP_NO_SSLv2
1921result |= SSL_OP_NO_SSLv2;
1922#endif
77bb000f
PP
1923
1924if (option_spec == NULL)
1925 {
1926 *results = result;
1927 return TRUE;
1928 }
1929
1930for (s=option_spec; *s != '\0'; /**/)
1931 {
1932 while (isspace(*s)) ++s;
1933 if (*s == '\0')
1934 break;
1935 if (*s != '+' && *s != '-')
1936 {
1937 DEBUG(D_tls) debug_printf("malformed openssl option setting: "
0e944a0d 1938 "+ or - expected but found \"%s\"\n", s);
77bb000f
PP
1939 return FALSE;
1940 }
1941 adding = *s++ == '+';
1942 for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ;
1943 keep_c = *end;
1944 *end = '\0';
1945 item_parsed = tls_openssl_one_option_parse(s, &item);
1946 if (!item_parsed)
1947 {
0e944a0d 1948 DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s);
77bb000f
PP
1949 return FALSE;
1950 }
1951 DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n",
1952 adding ? "adding" : "removing", result, item, s);
1953 if (adding)
1954 result |= item;
1955 else
1956 result &= ~item;
1957 *end = keep_c;
1958 s = end;
1959 }
1960
1961*results = result;
1962return TRUE;
1963}
1964
059ec3d9 1965/* End of tls-openssl.c */