testsuite output changes
[exim.git] / src / src / tls-openssl.c
CommitLineData
059ec3d9
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
d4e5e70b 5/* Copyright (c) University of Cambridge 1995 - 2017 */
059ec3d9
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6/* See the file NOTICE for conditions of use and distribution. */
7
f5d78688
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8/* Portions Copyright (c) The OpenSSL Project 1999 */
9
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10/* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
11library. It is #included into the tls.c file when that library is used. The
12code herein is based on a patch that was originally contributed by Steve
13Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara.
14
15No cryptographic code is included in Exim. All this module does is to call
16functions 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>
10ca4f1c
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25#ifndef OPENSSL_NO_ECDH
26# include <openssl/ec.h>
27#endif
f2de3a33 28#ifndef DISABLE_OCSP
e51c7be2 29# include <openssl/ocsp.h>
3f7eeb86 30#endif
85098ee7
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31#ifdef EXPERIMENTAL_DANE
32# include <danessl.h>
33#endif
34
3f7eeb86 35
f2de3a33
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36#ifndef DISABLE_OCSP
37# define EXIM_OCSP_SKEW_SECONDS (300L)
38# define EXIM_OCSP_MAX_AGE (-1L)
3f7eeb86 39#endif
059ec3d9 40
3bcbbbe2 41#if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
e51c7be2 42# define EXIM_HAVE_OPENSSL_TLSEXT
3bcbbbe2 43#endif
c8dfb21d
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44#if OPENSSL_VERSION_NUMBER >= 0x00908000L
45# define EXIM_HAVE_RSA_GENKEY_EX
46#endif
47#if OPENSSL_VERSION_NUMBER >= 0x10100000L
48# define EXIM_HAVE_OCSP_RESP_COUNT
49#else
50# define EXIM_HAVE_EPHEM_RSA_KEX
51# define EXIM_HAVE_RAND_PSEUDO
52#endif
53#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
54# define EXIM_HAVE_SHA256
55#endif
34e3241d
PP
56
57/*
58 * X509_check_host provides sane certificate hostname checking, but was added
59 * to OpenSSL late, after other projects forked off the code-base. So in
60 * addition to guarding against the base version number, beware that LibreSSL
61 * does not (at this time) support this function.
62 *
63 * If LibreSSL gains a different API, perhaps via libtls, then we'll probably
64 * opt to disentangle and ask a LibreSSL user to provide glue for a third
65 * crypto provider for libtls instead of continuing to tie the OpenSSL glue
66 * into even twistier knots. If LibreSSL gains the same API, we can just
67 * change this guard and punt the issue for a while longer.
68 */
69#ifndef LIBRESSL_VERSION_NUMBER
70# if OPENSSL_VERSION_NUMBER >= 0x010100000L
71# define EXIM_HAVE_OPENSSL_CHECKHOST
72# endif
73# if OPENSSL_VERSION_NUMBER >= 0x010000000L \
2dfb468b 74 && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L
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PP
75# define EXIM_HAVE_OPENSSL_CHECKHOST
76# endif
11aa88b0 77#endif
10ca4f1c 78
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79#if !defined(LIBRESSL_VERSION_NUMBER) \
80 || LIBRESSL_VERSION_NUMBER >= 0x20010000L
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81# if !defined(OPENSSL_NO_ECDH)
82# if OPENSSL_VERSION_NUMBER >= 0x0090800fL
83# define EXIM_HAVE_ECDH
84# endif
85# if OPENSSL_VERSION_NUMBER >= 0x10002000L
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86# define EXIM_HAVE_OPENSSL_EC_NIST2NID
87# endif
88# endif
2dfb468b 89#endif
3bcbbbe2 90
67791ce4
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91#if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP)
92# warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile"
93# define DISABLE_OCSP
94#endif
95
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96/* Structure for collecting random data for seeding. */
97
98typedef struct randstuff {
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99 struct timeval tv;
100 pid_t p;
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101} randstuff;
102
103/* Local static variables */
104
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105static BOOL client_verify_callback_called = FALSE;
106static BOOL server_verify_callback_called = FALSE;
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107static const uschar *sid_ctx = US"exim";
108
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PP
109/* We have three different contexts to care about.
110
111Simple case: client, `client_ctx`
112 As a client, we can be doing a callout or cut-through delivery while receiving
113 a message. So we have a client context, which should have options initialised
114 from the SMTP Transport.
115
116Server:
117 There are two cases: with and without ServerNameIndication from the client.
118 Given TLS SNI, we can be using different keys, certs and various other
119 configuration settings, because they're re-expanded with $tls_sni set. This
120 allows vhosting with TLS. This SNI is sent in the handshake.
121 A client might not send SNI, so we need a fallback, and an initial setup too.
122 So as a server, we start out using `server_ctx`.
123 If SNI is sent by the client, then we as server, mid-negotiation, try to clone
124 `server_sni` from `server_ctx` and then initialise settings by re-expanding
125 configuration.
126*/
127
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128static SSL_CTX *client_ctx = NULL;
129static SSL_CTX *server_ctx = NULL;
130static SSL *client_ssl = NULL;
131static SSL *server_ssl = NULL;
389ca47a 132
35731706 133#ifdef EXIM_HAVE_OPENSSL_TLSEXT
817d9f57 134static SSL_CTX *server_sni = NULL;
35731706 135#endif
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136
137static char ssl_errstring[256];
138
139static int ssl_session_timeout = 200;
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140static BOOL client_verify_optional = FALSE;
141static BOOL server_verify_optional = FALSE;
059ec3d9 142
f5d78688 143static BOOL reexpand_tls_files_for_sni = FALSE;
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144
145
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146typedef struct tls_ext_ctx_cb {
147 uschar *certificate;
148 uschar *privatekey;
f2de3a33 149#ifndef DISABLE_OCSP
f5d78688 150 BOOL is_server;
c3033f13 151 STACK_OF(X509) *verify_stack; /* chain for verifying the proof */
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152 union {
153 struct {
154 uschar *file;
155 uschar *file_expanded;
156 OCSP_RESPONSE *response;
157 } server;
158 struct {
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159 X509_STORE *verify_store; /* non-null if status requested */
160 BOOL verify_required;
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161 } client;
162 } u_ocsp;
3f7eeb86 163#endif
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PP
164 uschar *dhparam;
165 /* these are cached from first expand */
166 uschar *server_cipher_list;
167 /* only passed down to tls_error: */
168 host_item *host;
55414b25 169 const uschar * verify_cert_hostnames;
0cbf2b82 170#ifndef DISABLE_EVENT
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171 uschar * event_action;
172#endif
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PP
173} tls_ext_ctx_cb;
174
175/* should figure out a cleanup of API to handle state preserved per
176implementation, for various reasons, which can be void * in the APIs.
177For now, we hack around it. */
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178tls_ext_ctx_cb *client_static_cbinfo = NULL;
179tls_ext_ctx_cb *server_static_cbinfo = NULL;
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180
181static int
983207c1 182setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
cf0c6164 183 int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr );
059ec3d9 184
3f7eeb86 185/* Callbacks */
3bcbbbe2 186#ifdef EXIM_HAVE_OPENSSL_TLSEXT
3f7eeb86 187static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg);
3bcbbbe2 188#endif
f2de3a33 189#ifndef DISABLE_OCSP
f5d78688 190static int tls_server_stapling_cb(SSL *s, void *arg);
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191#endif
192
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193
194/*************************************************
195* Handle TLS error *
196*************************************************/
197
198/* Called from lots of places when errors occur before actually starting to do
199the TLS handshake, that is, while the session is still in clear. Always returns
200DEFER for a server and FAIL for a client so that most calls can use "return
201tls_error(...)" to do this processing and then give an appropriate return. A
202single function is used for both server and client, because it is called from
203some shared functions.
204
205Argument:
206 prefix text to include in the logged error
207 host NULL if setting up a server;
208 the connected host if setting up a client
7199e1ee 209 msg error message or NULL if we should ask OpenSSL
cf0c6164 210 errstr pointer to output error message
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211
212Returns: OK/DEFER/FAIL
213*/
214
215static int
cf0c6164 216tls_error(uschar * prefix, const host_item * host, uschar * msg, uschar ** errstr)
059ec3d9 217{
c562fd30 218if (!msg)
7199e1ee
TF
219 {
220 ERR_error_string(ERR_get_error(), ssl_errstring);
cf0c6164 221 msg = US ssl_errstring;
7199e1ee
TF
222 }
223
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JH
224if (errstr) *errstr = string_sprintf("(%s): %s", prefix, msg);
225return host ? FAIL : DEFER;
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226}
227
228
229
c8dfb21d 230#ifdef EXIM_HAVE_EPHEM_RSA_KEX
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231/*************************************************
232* Callback to generate RSA key *
233*************************************************/
234
235/*
236Arguments:
237 s SSL connection
238 export not used
239 keylength keylength
240
241Returns: pointer to generated key
242*/
243
244static RSA *
245rsa_callback(SSL *s, int export, int keylength)
246{
247RSA *rsa_key;
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248#ifdef EXIM_HAVE_RSA_GENKEY_EX
249BIGNUM *bn = BN_new();
250#endif
251
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252export = export; /* Shut picky compilers up */
253DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength);
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254
255#ifdef EXIM_HAVE_RSA_GENKEY_EX
256if ( !BN_set_word(bn, (unsigned long)RSA_F4)
f2cb6292 257 || !(rsa_key = RSA_new())
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258 || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL)
259 )
260#else
23bb6982 261if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL)))
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262#endif
263
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264 {
265 ERR_error_string(ERR_get_error(), ssl_errstring);
266 log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s",
267 ssl_errstring);
268 return NULL;
269 }
270return rsa_key;
271}
c8dfb21d 272#endif
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273
274
275
f5d78688 276/* Extreme debug
f2de3a33 277#ifndef DISABLE_OCSP
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278void
279x509_store_dump_cert_s_names(X509_STORE * store)
280{
281STACK_OF(X509_OBJECT) * roots= store->objs;
282int i;
283static uschar name[256];
284
285for(i= 0; i<sk_X509_OBJECT_num(roots); i++)
286 {
287 X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i);
288 if(tmp_obj->type == X509_LU_X509)
289 {
290 X509 * current_cert= tmp_obj->data.x509;
291 X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name));
f69979cf 292 name[sizeof(name)-1] = '\0';
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293 debug_printf(" %s\n", name);
294 }
295 }
296}
297#endif
298*/
299
059ec3d9 300
0cbf2b82 301#ifndef DISABLE_EVENT
f69979cf
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302static int
303verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn,
304 BOOL *calledp, const BOOL *optionalp, const uschar * what)
305{
306uschar * ev;
307uschar * yield;
308X509 * old_cert;
309
310ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
311if (ev)
312 {
aaba7d03 313 DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth);
f69979cf
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314 old_cert = tlsp->peercert;
315 tlsp->peercert = X509_dup(cert);
316 /* NB we do not bother setting peerdn */
317 if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth))))
318 {
319 log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: "
320 "depth=%d cert=%s: %s",
321 tlsp == &tls_out ? deliver_host_address : sender_host_address,
322 what, depth, dn, yield);
323 *calledp = TRUE;
324 if (!*optionalp)
325 {
326 if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */
327 return 1; /* reject (leaving peercert set) */
328 }
329 DEBUG(D_tls) debug_printf("Event-action verify failure overridden "
330 "(host in tls_try_verify_hosts)\n");
331 }
332 X509_free(tlsp->peercert);
333 tlsp->peercert = old_cert;
334 }
335return 0;
336}
337#endif
338
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339/*************************************************
340* Callback for verification *
341*************************************************/
342
343/* The SSL library does certificate verification if set up to do so. This
344callback has the current yes/no state is in "state". If verification succeeded,
f69979cf
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345we set the certificate-verified flag. If verification failed, what happens
346depends on whether the client is required to present a verifiable certificate
347or not.
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348
349If verification is optional, we change the state to yes, but still log the
350verification error. For some reason (it really would help to have proper
351documentation of OpenSSL), this callback function then gets called again, this
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352time with state = 1. We must take care not to set the private verified flag on
353the second time through.
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354
355Note: this function is not called if the client fails to present a certificate
356when asked. We get here only if a certificate has been received. Handling of
357optional verification for this case is done when requesting SSL to verify, by
358setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case.
359
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360May be called multiple times for different issues with a certificate, even
361for a given "depth" in the certificate chain.
362
059ec3d9 363Arguments:
f2f2c91b
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364 preverify_ok current yes/no state as 1/0
365 x509ctx certificate information.
366 tlsp per-direction (client vs. server) support data
367 calledp has-been-called flag
368 optionalp verification-is-optional flag
059ec3d9 369
f2f2c91b 370Returns: 0 if verification should fail, otherwise 1
059ec3d9
PH
371*/
372
373static int
f2f2c91b 374verify_callback(int preverify_ok, X509_STORE_CTX *x509ctx,
421aff85 375 tls_support *tlsp, BOOL *calledp, BOOL *optionalp)
059ec3d9 376{
421aff85 377X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
a7538db1 378int depth = X509_STORE_CTX_get_error_depth(x509ctx);
f69979cf 379uschar dn[256];
059ec3d9 380
f69979cf
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381X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn));
382dn[sizeof(dn)-1] = '\0';
059ec3d9 383
f2f2c91b 384if (preverify_ok == 0)
059ec3d9 385 {
4c01d6ab
JH
386 log_write(0, LOG_MAIN, "[%s] SSL verify error: depth=%d error=%s cert=%s",
387 tlsp == &tls_out ? deliver_host_address : sender_host_address,
a7538db1 388 depth,
421aff85 389 X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)),
f69979cf 390 dn);
a2ff477a 391 *calledp = TRUE;
9d1c15ef
JH
392 if (!*optionalp)
393 {
f69979cf
JH
394 if (!tlsp->peercert)
395 tlsp->peercert = X509_dup(cert); /* record failing cert */
396 return 0; /* reject */
9d1c15ef 397 }
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398 DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
399 "tls_try_verify_hosts)\n");
059ec3d9
PH
400 }
401
a7538db1 402else if (depth != 0)
059ec3d9 403 {
f69979cf 404 DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn);
f2de3a33 405#ifndef DISABLE_OCSP
f5d78688
JH
406 if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store)
407 { /* client, wanting stapling */
408 /* Add the server cert's signing chain as the one
409 for the verification of the OCSP stapled information. */
94431adb 410
f5d78688 411 if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store,
421aff85 412 cert))
f5d78688 413 ERR_clear_error();
c3033f13 414 sk_X509_push(client_static_cbinfo->verify_stack, cert);
f5d78688
JH
415 }
416#endif
0cbf2b82 417#ifndef DISABLE_EVENT
f69979cf
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418 if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL"))
419 return 0; /* reject, with peercert set */
a7538db1 420#endif
059ec3d9
PH
421 }
422else
423 {
55414b25 424 const uschar * verify_cert_hostnames;
e51c7be2 425
e51c7be2
JH
426 if ( tlsp == &tls_out
427 && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames)))
428 /* client, wanting hostname check */
e51c7be2 429 {
f69979cf 430
740f36d4 431#ifdef EXIM_HAVE_OPENSSL_CHECKHOST
f69979cf
JH
432# ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
433# define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0
434# endif
435# ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
436# define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0
437# endif
e51c7be2 438 int sep = 0;
55414b25 439 const uschar * list = verify_cert_hostnames;
e51c7be2 440 uschar * name;
d8e7834a
JH
441 int rc;
442 while ((name = string_nextinlist(&list, &sep, NULL, 0)))
f40d5be3 443 if ((rc = X509_check_host(cert, CCS name, 0,
8d692470 444 X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
740f36d4
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445 | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS,
446 NULL)))
d8e7834a
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447 {
448 if (rc < 0)
449 {
93a6fce2 450 log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error",
8cfd0f7b 451 deliver_host_address);
d8e7834a
JH
452 name = NULL;
453 }
e51c7be2 454 break;
d8e7834a 455 }
e51c7be2 456 if (!name)
f69979cf 457#else
e51c7be2 458 if (!tls_is_name_for_cert(verify_cert_hostnames, cert))
f69979cf 459#endif
e51c7be2
JH
460 {
461 log_write(0, LOG_MAIN,
b999c483
JH
462 "[%s] SSL verify error: certificate name mismatch: "
463 "DN=\"%s\" H=\"%s\"",
464 deliver_host_address, dn, verify_cert_hostnames);
a3ef7310
JH
465 *calledp = TRUE;
466 if (!*optionalp)
f69979cf
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467 {
468 if (!tlsp->peercert)
469 tlsp->peercert = X509_dup(cert); /* record failing cert */
470 return 0; /* reject */
471 }
a3ef7310
JH
472 DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
473 "tls_try_verify_hosts)\n");
e51c7be2 474 }
f69979cf 475 }
e51c7be2 476
0cbf2b82 477#ifndef DISABLE_EVENT
f69979cf
JH
478 if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL"))
479 return 0; /* reject, with peercert set */
e51c7be2
JH
480#endif
481
93dcb1c2 482 DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n",
f69979cf 483 *calledp ? "" : " authenticated", dn);
93dcb1c2
JH
484 if (!*calledp) tlsp->certificate_verified = TRUE;
485 *calledp = TRUE;
059ec3d9
PH
486 }
487
a7538db1 488return 1; /* accept, at least for this level */
059ec3d9
PH
489}
490
a2ff477a 491static int
f2f2c91b 492verify_callback_client(int preverify_ok, X509_STORE_CTX *x509ctx)
a2ff477a 493{
f2f2c91b
JH
494return verify_callback(preverify_ok, x509ctx, &tls_out,
495 &client_verify_callback_called, &client_verify_optional);
a2ff477a
JH
496}
497
498static int
f2f2c91b 499verify_callback_server(int preverify_ok, X509_STORE_CTX *x509ctx)
a2ff477a 500{
f2f2c91b
JH
501return verify_callback(preverify_ok, x509ctx, &tls_in,
502 &server_verify_callback_called, &server_verify_optional);
a2ff477a
JH
503}
504
059ec3d9 505
e5cccda9 506#ifdef EXPERIMENTAL_DANE
53a7196b 507
e5cccda9
JH
508/* This gets called *by* the dane library verify callback, which interposes
509itself.
510*/
511static int
f2f2c91b 512verify_callback_client_dane(int preverify_ok, X509_STORE_CTX * x509ctx)
e5cccda9
JH
513{
514X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
f69979cf 515uschar dn[256];
83b27293 516int depth = X509_STORE_CTX_get_error_depth(x509ctx);
5c75db2e 517#ifndef DISABLE_EVENT
f69979cf 518BOOL dummy_called, optional = FALSE;
83b27293 519#endif
e5cccda9 520
f69979cf
JH
521X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn));
522dn[sizeof(dn)-1] = '\0';
e5cccda9 523
f2f2c91b
JH
524DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s depth %d %s\n",
525 preverify_ok ? "ok":"BAD", depth, dn);
e5cccda9 526
0cbf2b82 527#ifndef DISABLE_EVENT
f69979cf
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528 if (verify_event(&tls_out, cert, depth, dn,
529 &dummy_called, &optional, US"DANE"))
530 return 0; /* reject, with peercert set */
83b27293
JH
531#endif
532
f2f2c91b 533if (preverify_ok == 1)
53a7196b 534 tls_out.dane_verified =
e5cccda9 535 tls_out.certificate_verified = TRUE;
f2f2c91b
JH
536else
537 {
538 int err = X509_STORE_CTX_get_error(x509ctx);
539 DEBUG(D_tls)
540 debug_printf(" - err %d '%s'\n", err, X509_verify_cert_error_string(err));
3c51463e 541 if (err == X509_V_ERR_APPLICATION_VERIFICATION)
f2f2c91b
JH
542 preverify_ok = 1;
543 }
544return preverify_ok;
e5cccda9 545}
53a7196b
JH
546
547#endif /*EXPERIMENTAL_DANE*/
e5cccda9 548
059ec3d9
PH
549
550/*************************************************
551* Information callback *
552*************************************************/
553
554/* The SSL library functions call this from time to time to indicate what they
7be682ca
PP
555are doing. We copy the string to the debugging output when TLS debugging has
556been requested.
059ec3d9
PH
557
558Arguments:
559 s the SSL connection
560 where
561 ret
562
563Returns: nothing
564*/
565
566static void
567info_callback(SSL *s, int where, int ret)
568{
569where = where;
570ret = ret;
571DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s));
572}
573
574
575
576/*************************************************
577* Initialize for DH *
578*************************************************/
579
580/* If dhparam is set, expand it, and load up the parameters for DH encryption.
581
582Arguments:
038597d2 583 sctx The current SSL CTX (inbound or outbound)
a799883d 584 dhparam DH parameter file or fixed parameter identity string
7199e1ee 585 host connected host, if client; NULL if server
cf0c6164 586 errstr error string pointer
059ec3d9
PH
587
588Returns: TRUE if OK (nothing to set up, or setup worked)
589*/
590
591static BOOL
cf0c6164 592init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr)
059ec3d9 593{
059ec3d9
PH
594BIO *bio;
595DH *dh;
596uschar *dhexpanded;
a799883d 597const char *pem;
059ec3d9 598
cf0c6164 599if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr))
059ec3d9
PH
600 return FALSE;
601
0df4ab80 602if (!dhexpanded || !*dhexpanded)
a799883d 603 bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1);
a799883d 604else if (dhexpanded[0] == '/')
059ec3d9 605 {
0df4ab80 606 if (!(bio = BIO_new_file(CS dhexpanded, "r")))
059ec3d9 607 {
7199e1ee 608 tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
cf0c6164 609 host, US strerror(errno), errstr);
a799883d 610 return FALSE;
059ec3d9 611 }
a799883d
PP
612 }
613else
614 {
615 if (Ustrcmp(dhexpanded, "none") == 0)
059ec3d9 616 {
a799883d
PP
617 DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
618 return TRUE;
059ec3d9 619 }
a799883d 620
0df4ab80 621 if (!(pem = std_dh_prime_named(dhexpanded)))
a799883d
PP
622 {
623 tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded),
cf0c6164 624 host, US strerror(errno), errstr);
a799883d
PP
625 return FALSE;
626 }
627 bio = BIO_new_mem_buf(CS pem, -1);
628 }
629
0df4ab80 630if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)))
a799883d 631 {
059ec3d9 632 BIO_free(bio);
a799883d 633 tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded),
cf0c6164 634 host, NULL, errstr);
a799883d
PP
635 return FALSE;
636 }
637
638/* Even if it is larger, we silently return success rather than cause things
639 * to fail out, so that a too-large DH will not knock out all TLS; it's a
640 * debatable choice. */
641if ((8*DH_size(dh)) > tls_dh_max_bits)
642 {
643 DEBUG(D_tls)
170f4904 644 debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n",
a799883d
PP
645 8*DH_size(dh), tls_dh_max_bits);
646 }
647else
648 {
649 SSL_CTX_set_tmp_dh(sctx, dh);
650 DEBUG(D_tls)
651 debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n",
652 dhexpanded ? dhexpanded : US"default", 8*DH_size(dh));
059ec3d9
PH
653 }
654
a799883d
PP
655DH_free(dh);
656BIO_free(bio);
657
658return TRUE;
059ec3d9
PH
659}
660
661
662
663
038597d2
PP
664/*************************************************
665* Initialize for ECDH *
666*************************************************/
667
668/* Load parameters for ECDH encryption.
669
670For now, we stick to NIST P-256 because: it's simple and easy to configure;
671it avoids any patent issues that might bite redistributors; despite events in
672the news and concerns over curve choices, we're not cryptographers, we're not
673pretending to be, and this is "good enough" to be better than no support,
674protecting against most adversaries. Given another year or two, there might
675be sufficient clarity about a "right" way forward to let us make an informed
676decision, instead of a knee-jerk reaction.
677
678Longer-term, we should look at supporting both various named curves and
679external files generated with "openssl ecparam", much as we do for init_dh().
680We should also support "none" as a value, to explicitly avoid initialisation.
681
682Patches welcome.
683
684Arguments:
685 sctx The current SSL CTX (inbound or outbound)
686 host connected host, if client; NULL if server
cf0c6164 687 errstr error string pointer
038597d2
PP
688
689Returns: TRUE if OK (nothing to set up, or setup worked)
690*/
691
692static BOOL
cf0c6164 693init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr)
038597d2 694{
63f0dbe0
JH
695#ifdef OPENSSL_NO_ECDH
696return TRUE;
697#else
698
10ca4f1c
JH
699EC_KEY * ecdh;
700uschar * exp_curve;
701int nid;
702BOOL rv;
703
038597d2
PP
704if (host) /* No ECDH setup for clients, only for servers */
705 return TRUE;
706
10ca4f1c 707# ifndef EXIM_HAVE_ECDH
038597d2
PP
708DEBUG(D_tls)
709 debug_printf("No OpenSSL API to define ECDH parameters, skipping\n");
710return TRUE;
038597d2 711# else
10ca4f1c 712
cf0c6164 713if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr))
10ca4f1c
JH
714 return FALSE;
715if (!exp_curve || !*exp_curve)
716 return TRUE;
717
8e53a4fc 718/* "auto" needs to be handled carefully.
4c04137d 719 * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1
8e53a4fc 720 * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto
4c04137d 721 * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO)
8e53a4fc
HSHR
722 * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection
723 * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b
724 */
10ca4f1c 725if (Ustrcmp(exp_curve, "auto") == 0)
038597d2 726 {
8e53a4fc 727#if OPENSSL_VERSION_NUMBER < 0x10002000L
10ca4f1c 728 DEBUG(D_tls) debug_printf(
8e53a4fc 729 "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n");
78a3bbd5 730 exp_curve = US"prime256v1";
8e53a4fc
HSHR
731#else
732# if defined SSL_CTRL_SET_ECDH_AUTO
733 DEBUG(D_tls) debug_printf(
734 "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n");
10ca4f1c
JH
735 SSL_CTX_set_ecdh_auto(sctx, 1);
736 return TRUE;
8e53a4fc
HSHR
737# else
738 DEBUG(D_tls) debug_printf(
739 "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n");
740 return TRUE;
741# endif
742#endif
10ca4f1c 743 }
038597d2 744
10ca4f1c
JH
745DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve);
746if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef
747# ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID
748 && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef
749# endif
750 )
751 {
cf0c6164
JH
752 tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve),
753 host, NULL, errstr);
10ca4f1c
JH
754 return FALSE;
755 }
038597d2 756
10ca4f1c
JH
757if (!(ecdh = EC_KEY_new_by_curve_name(nid)))
758 {
cf0c6164 759 tls_error(US"Unable to create ec curve", host, NULL, errstr);
10ca4f1c 760 return FALSE;
038597d2 761 }
10ca4f1c
JH
762
763/* The "tmp" in the name here refers to setting a temporary key
764not to the stability of the interface. */
765
766if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0))
cf0c6164 767 tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr);
10ca4f1c
JH
768else
769 DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve);
770
771EC_KEY_free(ecdh);
772return !rv;
773
774# endif /*EXIM_HAVE_ECDH*/
775#endif /*OPENSSL_NO_ECDH*/
038597d2
PP
776}
777
778
779
780
f2de3a33 781#ifndef DISABLE_OCSP
3f7eeb86
PP
782/*************************************************
783* Load OCSP information into state *
784*************************************************/
f5d78688 785/* Called to load the server OCSP response from the given file into memory, once
3f7eeb86
PP
786caller has determined this is needed. Checks validity. Debugs a message
787if invalid.
788
789ASSUMES: single response, for single cert.
790
791Arguments:
792 sctx the SSL_CTX* to update
793 cbinfo various parts of session state
794 expanded the filename putatively holding an OCSP response
795
796*/
797
798static void
f5d78688 799ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded)
3f7eeb86 800{
ee5b1e28
JH
801BIO * bio;
802OCSP_RESPONSE * resp;
803OCSP_BASICRESP * basic_response;
804OCSP_SINGLERESP * single_response;
805ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd;
ee5b1e28 806STACK_OF(X509) * sk;
3f7eeb86
PP
807unsigned long verify_flags;
808int status, reason, i;
809
f5d78688
JH
810cbinfo->u_ocsp.server.file_expanded = string_copy(expanded);
811if (cbinfo->u_ocsp.server.response)
3f7eeb86 812 {
f5d78688
JH
813 OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response);
814 cbinfo->u_ocsp.server.response = NULL;
3f7eeb86
PP
815 }
816
ee5b1e28 817if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb")))
3f7eeb86
PP
818 {
819 DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n",
f5d78688 820 cbinfo->u_ocsp.server.file_expanded);
3f7eeb86
PP
821 return;
822 }
823
824resp = d2i_OCSP_RESPONSE_bio(bio, NULL);
825BIO_free(bio);
826if (!resp)
827 {
828 DEBUG(D_tls) debug_printf("Error reading OCSP response.\n");
829 return;
830 }
831
ee5b1e28 832if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL)
3f7eeb86
PP
833 {
834 DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n",
835 OCSP_response_status_str(status), status);
f5d78688 836 goto bad;
3f7eeb86
PP
837 }
838
ee5b1e28 839if (!(basic_response = OCSP_response_get1_basic(resp)))
3f7eeb86
PP
840 {
841 DEBUG(D_tls)
842 debug_printf("OCSP response parse error: unable to extract basic response.\n");
f5d78688 843 goto bad;
3f7eeb86
PP
844 }
845
c3033f13 846sk = cbinfo->verify_stack;
3f7eeb86
PP
847verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */
848
849/* May need to expose ability to adjust those flags?
850OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT
851OCSP_TRUSTOTHER OCSP_NOINTERN */
852
4c04137d 853/* This does a full verify on the OCSP proof before we load it for serving
ee5b1e28
JH
854up; possibly overkill - just date-checks might be nice enough.
855
856OCSP_basic_verify takes a "store" arg, but does not
857use it for the chain verification, which is all we do
858when OCSP_NOVERIFY is set. The content from the wire
859"basic_response" and a cert-stack "sk" are all that is used.
860
c3033f13
JH
861We have a stack, loaded in setup_certs() if tls_verify_certificates
862was a file (not a directory, or "system"). It is unfortunate we
863cannot used the connection context store, as that would neatly
864handle the "system" case too, but there seems to be no library
865function for getting a stack from a store.
e3555426 866[ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ]
c3033f13
JH
867We do not free the stack since it could be needed a second time for
868SNI handling.
869
4c04137d 870Separately we might try to replace using OCSP_basic_verify() - which seems to not
ee5b1e28
JH
871be a public interface into the OpenSSL library (there's no manual entry) -
872But what with? We also use OCSP_basic_verify in the client stapling callback.
4c04137d 873And there we NEED it; we must verify that status... unless the
ee5b1e28
JH
874library does it for us anyway? */
875
876if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0)
3f7eeb86 877 {
ee5b1e28
JH
878 DEBUG(D_tls)
879 {
3f7eeb86
PP
880 ERR_error_string(ERR_get_error(), ssl_errstring);
881 debug_printf("OCSP response verify failure: %s\n", US ssl_errstring);
f5d78688
JH
882 }
883 goto bad;
3f7eeb86
PP
884 }
885
886/* Here's the simplifying assumption: there's only one response, for the
887one certificate we use, and nothing for anything else in a chain. If this
888proves false, we need to extract a cert id from our issued cert
889(tls_certificate) and use that for OCSP_resp_find_status() (which finds the
890right cert in the stack and then calls OCSP_single_get0_status()).
891
892I'm hoping to avoid reworking a bunch more of how we handle state here. */
ee5b1e28
JH
893
894if (!(single_response = OCSP_resp_get0(basic_response, 0)))
3f7eeb86
PP
895 {
896 DEBUG(D_tls)
897 debug_printf("Unable to get first response from OCSP basic response.\n");
f5d78688 898 goto bad;
3f7eeb86
PP
899 }
900
901status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd);
f5d78688 902if (status != V_OCSP_CERTSTATUS_GOOD)
3f7eeb86 903 {
f5d78688
JH
904 DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n",
905 OCSP_cert_status_str(status), status,
906 OCSP_crl_reason_str(reason), reason);
907 goto bad;
3f7eeb86
PP
908 }
909
910if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
911 {
912 DEBUG(D_tls) debug_printf("OCSP status invalid times.\n");
f5d78688 913 goto bad;
3f7eeb86
PP
914 }
915
f5d78688 916supply_response:
018058b2 917 cbinfo->u_ocsp.server.response = resp;
f5d78688
JH
918return;
919
920bad:
018058b2
JH
921 if (running_in_test_harness)
922 {
923 extern char ** environ;
924 uschar ** p;
bc3c7bb7 925 if (environ) for (p = USS environ; *p != NULL; p++)
018058b2
JH
926 if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
927 {
928 DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n");
929 goto supply_response;
930 }
931 }
f5d78688 932return;
3f7eeb86 933}
f2de3a33 934#endif /*!DISABLE_OCSP*/
3f7eeb86
PP
935
936
937
938
23bb6982
JH
939/* Create and install a selfsigned certificate, for use in server mode */
940
941static int
cf0c6164 942tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr)
23bb6982
JH
943{
944X509 * x509 = NULL;
945EVP_PKEY * pkey;
946RSA * rsa;
947X509_NAME * name;
948uschar * where;
949
950where = US"allocating pkey";
951if (!(pkey = EVP_PKEY_new()))
952 goto err;
953
954where = US"allocating cert";
955if (!(x509 = X509_new()))
956 goto err;
957
958where = US"generating pkey";
959 /* deprecated, use RSA_generate_key_ex() */
960if (!(rsa = RSA_generate_key(1024, RSA_F4, NULL, NULL)))
961 goto err;
962
4c04137d 963where = US"assigning pkey";
23bb6982
JH
964if (!EVP_PKEY_assign_RSA(pkey, rsa))
965 goto err;
966
967X509_set_version(x509, 2); /* N+1 - version 3 */
968ASN1_INTEGER_set(X509_get_serialNumber(x509), 0);
969X509_gmtime_adj(X509_get_notBefore(x509), 0);
970X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60); /* 1 hour */
971X509_set_pubkey(x509, pkey);
972
973name = X509_get_subject_name(x509);
974X509_NAME_add_entry_by_txt(name, "C",
4dc2379a 975 MBSTRING_ASC, CUS "UK", -1, -1, 0);
23bb6982 976X509_NAME_add_entry_by_txt(name, "O",
4dc2379a 977 MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0);
23bb6982 978X509_NAME_add_entry_by_txt(name, "CN",
4dc2379a 979 MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0);
23bb6982
JH
980X509_set_issuer_name(x509, name);
981
982where = US"signing cert";
983if (!X509_sign(x509, pkey, EVP_md5()))
984 goto err;
985
986where = US"installing selfsign cert";
987if (!SSL_CTX_use_certificate(sctx, x509))
988 goto err;
989
990where = US"installing selfsign key";
991if (!SSL_CTX_use_PrivateKey(sctx, pkey))
992 goto err;
993
994return OK;
995
996err:
cf0c6164 997 (void) tls_error(where, NULL, NULL, errstr);
23bb6982
JH
998 if (x509) X509_free(x509);
999 if (pkey) EVP_PKEY_free(pkey);
1000 return DEFER;
1001}
1002
1003
1004
1005
059ec3d9 1006/*************************************************
7be682ca
PP
1007* Expand key and cert file specs *
1008*************************************************/
1009
f5d78688 1010/* Called once during tls_init and possibly again during TLS setup, for a
7be682ca
PP
1011new context, if Server Name Indication was used and tls_sni was seen in
1012the certificate string.
1013
1014Arguments:
1015 sctx the SSL_CTX* to update
1016 cbinfo various parts of session state
cf0c6164 1017 errstr error string pointer
7be682ca
PP
1018
1019Returns: OK/DEFER/FAIL
1020*/
1021
1022static int
cf0c6164
JH
1023tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo,
1024 uschar ** errstr)
7be682ca
PP
1025{
1026uschar *expanded;
1027
23bb6982 1028if (!cbinfo->certificate)
7be682ca 1029 {
23bb6982
JH
1030 if (cbinfo->host) /* client */
1031 return OK;
1032 /* server */
cf0c6164 1033 if (tls_install_selfsign(sctx, errstr) != OK)
23bb6982 1034 return DEFER;
7be682ca 1035 }
23bb6982
JH
1036else
1037 {
1038 if (Ustrstr(cbinfo->certificate, US"tls_sni") ||
1039 Ustrstr(cbinfo->certificate, US"tls_in_sni") ||
1040 Ustrstr(cbinfo->certificate, US"tls_out_sni")
1041 )
1042 reexpand_tls_files_for_sni = TRUE;
7be682ca 1043
cf0c6164 1044 if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr))
23bb6982
JH
1045 return DEFER;
1046
1047 if (expanded != NULL)
1048 {
1049 DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded);
1050 if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded))
1051 return tls_error(string_sprintf(
1052 "SSL_CTX_use_certificate_chain_file file=%s", expanded),
cf0c6164 1053 cbinfo->host, NULL, errstr);
23bb6982 1054 }
7be682ca 1055
23bb6982 1056 if (cbinfo->privatekey != NULL &&
cf0c6164 1057 !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr))
23bb6982 1058 return DEFER;
7be682ca 1059
23bb6982
JH
1060 /* If expansion was forced to fail, key_expanded will be NULL. If the result
1061 of the expansion is an empty string, ignore it also, and assume the private
1062 key is in the same file as the certificate. */
1063
1064 if (expanded && *expanded)
1065 {
1066 DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded);
1067 if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM))
1068 return tls_error(string_sprintf(
cf0c6164 1069 "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL, errstr);
23bb6982 1070 }
7be682ca
PP
1071 }
1072
f2de3a33 1073#ifndef DISABLE_OCSP
f40d5be3 1074if (cbinfo->is_server && cbinfo->u_ocsp.server.file)
3f7eeb86 1075 {
cf0c6164 1076 if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr))
3f7eeb86
PP
1077 return DEFER;
1078
f40d5be3 1079 if (expanded && *expanded)
3f7eeb86
PP
1080 {
1081 DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded);
f40d5be3
JH
1082 if ( cbinfo->u_ocsp.server.file_expanded
1083 && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0))
3f7eeb86 1084 {
f40d5be3
JH
1085 DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n");
1086 }
1087 else
f40d5be3 1088 ocsp_load_response(sctx, cbinfo, expanded);
3f7eeb86
PP
1089 }
1090 }
1091#endif
1092
7be682ca
PP
1093return OK;
1094}
1095
1096
1097
1098
1099/*************************************************
1100* Callback to handle SNI *
1101*************************************************/
1102
1103/* Called when acting as server during the TLS session setup if a Server Name
1104Indication extension was sent by the client.
1105
1106API documentation is OpenSSL s_server.c implementation.
1107
1108Arguments:
1109 s SSL* of the current session
1110 ad unknown (part of OpenSSL API) (unused)
1111 arg Callback of "our" registered data
1112
1113Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK}
1114*/
1115
3bcbbbe2 1116#ifdef EXIM_HAVE_OPENSSL_TLSEXT
7be682ca 1117static int
7be682ca
PP
1118tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg)
1119{
1120const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
3f7eeb86 1121tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
7be682ca 1122int rc;
3f0945ff 1123int old_pool = store_pool;
cf0c6164 1124uschar * dummy_errstr;
7be682ca
PP
1125
1126if (!servername)
1127 return SSL_TLSEXT_ERR_OK;
1128
3f0945ff 1129DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername,
7be682ca
PP
1130 reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)");
1131
1132/* Make the extension value available for expansion */
3f0945ff 1133store_pool = POOL_PERM;
817d9f57 1134tls_in.sni = string_copy(US servername);
3f0945ff 1135store_pool = old_pool;
7be682ca
PP
1136
1137if (!reexpand_tls_files_for_sni)
1138 return SSL_TLSEXT_ERR_OK;
1139
1140/* Can't find an SSL_CTX_clone() or equivalent, so we do it manually;
1141not confident that memcpy wouldn't break some internal reference counting.
1142Especially since there's a references struct member, which would be off. */
1143
0df4ab80 1144if (!(server_sni = SSL_CTX_new(SSLv23_server_method())))
7be682ca
PP
1145 {
1146 ERR_error_string(ERR_get_error(), ssl_errstring);
1147 DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring);
1148 return SSL_TLSEXT_ERR_NOACK;
1149 }
1150
1151/* Not sure how many of these are actually needed, since SSL object
1152already exists. Might even need this selfsame callback, for reneg? */
1153
817d9f57
JH
1154SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx));
1155SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx));
1156SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx));
1157SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx));
1158SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
1159SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo);
038597d2 1160
cf0c6164
JH
1161if ( !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr)
1162 || !init_ecdh(server_sni, NULL, &dummy_errstr)
038597d2
PP
1163 )
1164 return SSL_TLSEXT_ERR_NOACK;
1165
7be682ca 1166if (cbinfo->server_cipher_list)
817d9f57 1167 SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list);
f2de3a33 1168#ifndef DISABLE_OCSP
f5d78688 1169if (cbinfo->u_ocsp.server.file)
3f7eeb86 1170 {
f5d78688 1171 SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb);
14c7b357 1172 SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo);
3f7eeb86
PP
1173 }
1174#endif
7be682ca 1175
c3033f13 1176if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE,
cf0c6164 1177 verify_callback_server, &dummy_errstr)) != OK)
c3033f13 1178 return SSL_TLSEXT_ERR_NOACK;
7be682ca 1179
3f7eeb86
PP
1180/* do this after setup_certs, because this can require the certs for verifying
1181OCSP information. */
cf0c6164 1182if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK)
0df4ab80 1183 return SSL_TLSEXT_ERR_NOACK;
a799883d 1184
7be682ca 1185DEBUG(D_tls) debug_printf("Switching SSL context.\n");
817d9f57 1186SSL_set_SSL_CTX(s, server_sni);
7be682ca
PP
1187
1188return SSL_TLSEXT_ERR_OK;
1189}
3bcbbbe2 1190#endif /* EXIM_HAVE_OPENSSL_TLSEXT */
7be682ca
PP
1191
1192
1193
1194
f2de3a33 1195#ifndef DISABLE_OCSP
f5d78688 1196
3f7eeb86
PP
1197/*************************************************
1198* Callback to handle OCSP Stapling *
1199*************************************************/
1200
1201/* Called when acting as server during the TLS session setup if the client
1202requests OCSP information with a Certificate Status Request.
1203
1204Documentation via openssl s_server.c and the Apache patch from the OpenSSL
1205project.
1206
1207*/
1208
1209static int
f5d78688 1210tls_server_stapling_cb(SSL *s, void *arg)
3f7eeb86
PP
1211{
1212const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
1213uschar *response_der;
1214int response_der_len;
1215
af4a1bca 1216DEBUG(D_tls)
b3ef41c9 1217 debug_printf("Received TLS status request (OCSP stapling); %s response\n",
f5d78688
JH
1218 cbinfo->u_ocsp.server.response ? "have" : "lack");
1219
44662487 1220tls_in.ocsp = OCSP_NOT_RESP;
f5d78688 1221if (!cbinfo->u_ocsp.server.response)
3f7eeb86
PP
1222 return SSL_TLSEXT_ERR_NOACK;
1223
1224response_der = NULL;
44662487
JH
1225response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response,
1226 &response_der);
3f7eeb86
PP
1227if (response_der_len <= 0)
1228 return SSL_TLSEXT_ERR_NOACK;
1229
5e55c7a9 1230SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len);
44662487 1231tls_in.ocsp = OCSP_VFIED;
3f7eeb86
PP
1232return SSL_TLSEXT_ERR_OK;
1233}
1234
3f7eeb86 1235
f5d78688
JH
1236static void
1237time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time)
1238{
1239BIO_printf(bp, "\t%s: ", str);
1240ASN1_GENERALIZEDTIME_print(bp, time);
1241BIO_puts(bp, "\n");
1242}
1243
1244static int
1245tls_client_stapling_cb(SSL *s, void *arg)
1246{
1247tls_ext_ctx_cb * cbinfo = arg;
1248const unsigned char * p;
1249int len;
1250OCSP_RESPONSE * rsp;
1251OCSP_BASICRESP * bs;
1252int i;
1253
1254DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):");
1255len = SSL_get_tlsext_status_ocsp_resp(s, &p);
1256if(!p)
1257 {
44662487 1258 /* Expect this when we requested ocsp but got none */
6c6d6e48 1259 if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher))
44662487 1260 log_write(0, LOG_MAIN, "Received TLS status callback, null content");
f5d78688
JH
1261 else
1262 DEBUG(D_tls) debug_printf(" null\n");
44662487 1263 return cbinfo->u_ocsp.client.verify_required ? 0 : 1;
f5d78688 1264 }
018058b2 1265
f5d78688
JH
1266if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len)))
1267 {
018058b2 1268 tls_out.ocsp = OCSP_FAILED;
6c6d6e48 1269 if (LOGGING(tls_cipher))
1eca31ca 1270 log_write(0, LOG_MAIN, "Received TLS cert status response, parse error");
f5d78688
JH
1271 else
1272 DEBUG(D_tls) debug_printf(" parse error\n");
1273 return 0;
1274 }
1275
1276if(!(bs = OCSP_response_get1_basic(rsp)))
1277 {
018058b2 1278 tls_out.ocsp = OCSP_FAILED;
6c6d6e48 1279 if (LOGGING(tls_cipher))
1eca31ca 1280 log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response");
f5d78688
JH
1281 else
1282 DEBUG(D_tls) debug_printf(" error parsing response\n");
1283 OCSP_RESPONSE_free(rsp);
1284 return 0;
1285 }
1286
1287/* We'd check the nonce here if we'd put one in the request. */
1288/* However that would defeat cacheability on the server so we don't. */
1289
f5d78688
JH
1290/* This section of code reworked from OpenSSL apps source;
1291 The OpenSSL Project retains copyright:
1292 Copyright (c) 1999 The OpenSSL Project. All rights reserved.
1293*/
1294 {
1295 BIO * bp = NULL;
f5d78688
JH
1296 int status, reason;
1297 ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd;
1298
1299 DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE);
1300
1301 /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */
1302
1303 /* Use the chain that verified the server cert to verify the stapled info */
1304 /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */
1305
c3033f13 1306 if ((i = OCSP_basic_verify(bs, cbinfo->verify_stack,
44662487 1307 cbinfo->u_ocsp.client.verify_store, 0)) <= 0)
f5d78688 1308 {
018058b2 1309 tls_out.ocsp = OCSP_FAILED;
6c6d6e48 1310 if (LOGGING(tls_cipher))
1eca31ca 1311 log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable");
f5d78688
JH
1312 BIO_printf(bp, "OCSP response verify failure\n");
1313 ERR_print_errors(bp);
c8dfb21d 1314 goto failed;
f5d78688
JH
1315 }
1316
1317 BIO_printf(bp, "OCSP response well-formed and signed OK\n");
1318
c8dfb21d
JH
1319 /*XXX So we have a good stapled OCSP status. How do we know
1320 it is for the cert of interest? OpenSSL 1.1.0 has a routine
1321 OCSP_resp_find_status() which matches on a cert id, which presumably
1322 we should use. Making an id needs OCSP_cert_id_new(), which takes
1323 issuerName, issuerKey, serialNumber. Are they all in the cert?
1324
1325 For now, carry on blindly accepting the resp. */
1326
f5d78688 1327 {
f5d78688
JH
1328 OCSP_SINGLERESP * single;
1329
c8dfb21d
JH
1330#ifdef EXIM_HAVE_OCSP_RESP_COUNT
1331 if (OCSP_resp_count(bs) != 1)
1332#else
1333 STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses;
f5d78688 1334 if (sk_OCSP_SINGLERESP_num(sresp) != 1)
c8dfb21d 1335#endif
f5d78688 1336 {
018058b2 1337 tls_out.ocsp = OCSP_FAILED;
44662487
JH
1338 log_write(0, LOG_MAIN, "OCSP stapling "
1339 "with multiple responses not handled");
c8dfb21d 1340 goto failed;
f5d78688
JH
1341 }
1342 single = OCSP_resp_get0(bs, 0);
44662487
JH
1343 status = OCSP_single_get0_status(single, &reason, &rev,
1344 &thisupd, &nextupd);
f5d78688
JH
1345 }
1346
f5d78688
JH
1347 DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd);
1348 DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd);
44662487
JH
1349 if (!OCSP_check_validity(thisupd, nextupd,
1350 EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
f5d78688 1351 {
018058b2 1352 tls_out.ocsp = OCSP_FAILED;
f5d78688
JH
1353 DEBUG(D_tls) ERR_print_errors(bp);
1354 log_write(0, LOG_MAIN, "Server OSCP dates invalid");
f5d78688 1355 }
44662487 1356 else
f5d78688 1357 {
44662487
JH
1358 DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n",
1359 OCSP_cert_status_str(status));
1360 switch(status)
1361 {
1362 case V_OCSP_CERTSTATUS_GOOD:
44662487 1363 tls_out.ocsp = OCSP_VFIED;
018058b2 1364 i = 1;
c8dfb21d 1365 goto good;
44662487 1366 case V_OCSP_CERTSTATUS_REVOKED:
018058b2 1367 tls_out.ocsp = OCSP_FAILED;
44662487
JH
1368 log_write(0, LOG_MAIN, "Server certificate revoked%s%s",
1369 reason != -1 ? "; reason: " : "",
1370 reason != -1 ? OCSP_crl_reason_str(reason) : "");
1371 DEBUG(D_tls) time_print(bp, "Revocation Time", rev);
44662487
JH
1372 break;
1373 default:
018058b2 1374 tls_out.ocsp = OCSP_FAILED;
44662487
JH
1375 log_write(0, LOG_MAIN,
1376 "Server certificate status unknown, in OCSP stapling");
44662487
JH
1377 break;
1378 }
f5d78688 1379 }
c8dfb21d
JH
1380 failed:
1381 i = cbinfo->u_ocsp.client.verify_required ? 0 : 1;
1382 good:
f5d78688
JH
1383 BIO_free(bp);
1384 }
1385
1386OCSP_RESPONSE_free(rsp);
1387return i;
1388}
f2de3a33 1389#endif /*!DISABLE_OCSP*/
3f7eeb86
PP
1390
1391
7be682ca 1392/*************************************************
059ec3d9
PH
1393* Initialize for TLS *
1394*************************************************/
1395
e51c7be2
JH
1396/* Called from both server and client code, to do preliminary initialization
1397of the library. We allocate and return a context structure.
059ec3d9
PH
1398
1399Arguments:
946ecbe0 1400 ctxp returned SSL context
059ec3d9
PH
1401 host connected host, if client; NULL if server
1402 dhparam DH parameter file
1403 certificate certificate file
1404 privatekey private key
f5d78688 1405 ocsp_file file of stapling info (server); flag for require ocsp (client)
059ec3d9 1406 addr address if client; NULL if server (for some randomness)
946ecbe0 1407 cbp place to put allocated callback context
cf0c6164 1408 errstr error string pointer
059ec3d9
PH
1409
1410Returns: OK/DEFER/FAIL
1411*/
1412
1413static int
817d9f57 1414tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate,
3f7eeb86 1415 uschar *privatekey,
f2de3a33 1416#ifndef DISABLE_OCSP
3f7eeb86
PP
1417 uschar *ocsp_file,
1418#endif
cf0c6164 1419 address_item *addr, tls_ext_ctx_cb ** cbp, uschar ** errstr)
059ec3d9 1420{
7006ee24 1421SSL_CTX * ctx;
77bb000f 1422long init_options;
7be682ca 1423int rc;
a7538db1 1424tls_ext_ctx_cb * cbinfo;
7be682ca
PP
1425
1426cbinfo = store_malloc(sizeof(tls_ext_ctx_cb));
1427cbinfo->certificate = certificate;
1428cbinfo->privatekey = privatekey;
f2de3a33 1429#ifndef DISABLE_OCSP
c3033f13 1430cbinfo->verify_stack = NULL;
f5d78688
JH
1431if ((cbinfo->is_server = host==NULL))
1432 {
1433 cbinfo->u_ocsp.server.file = ocsp_file;
1434 cbinfo->u_ocsp.server.file_expanded = NULL;
1435 cbinfo->u_ocsp.server.response = NULL;
1436 }
1437else
1438 cbinfo->u_ocsp.client.verify_store = NULL;
3f7eeb86 1439#endif
7be682ca 1440cbinfo->dhparam = dhparam;
0df4ab80 1441cbinfo->server_cipher_list = NULL;
7be682ca 1442cbinfo->host = host;
0cbf2b82 1443#ifndef DISABLE_EVENT
a7538db1
JH
1444cbinfo->event_action = NULL;
1445#endif
77bb000f 1446
059ec3d9
PH
1447SSL_load_error_strings(); /* basic set up */
1448OpenSSL_add_ssl_algorithms();
1449
c8dfb21d 1450#ifdef EXIM_HAVE_SHA256
77bb000f 1451/* SHA256 is becoming ever more popular. This makes sure it gets added to the
a0475b69
TK
1452list of available digests. */
1453EVP_add_digest(EVP_sha256());
cf1ef1a9 1454#endif
a0475b69 1455
f0f5a555
PP
1456/* Create a context.
1457The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant
1458negotiation in the different methods; as far as I can tell, the only
1459*_{server,client}_method which allows negotiation is SSLv23, which exists even
1460when OpenSSL is built without SSLv2 support.
1461By disabling with openssl_options, we can let admins re-enable with the
1462existing knob. */
059ec3d9 1463
7006ee24
JH
1464if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method())))
1465 return tls_error(US"SSL_CTX_new", host, NULL, errstr);
059ec3d9
PH
1466
1467/* It turns out that we need to seed the random number generator this early in
1468order to get the full complement of ciphers to work. It took me roughly a day
1469of work to discover this by experiment.
1470
1471On systems that have /dev/urandom, SSL may automatically seed itself from
1472there. Otherwise, we have to make something up as best we can. Double check
1473afterwards. */
1474
1475if (!RAND_status())
1476 {
1477 randstuff r;
9e3331ea 1478 gettimeofday(&r.tv, NULL);
059ec3d9
PH
1479 r.p = getpid();
1480
1481 RAND_seed((uschar *)(&r), sizeof(r));
1482 RAND_seed((uschar *)big_buffer, big_buffer_size);
1483 if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr));
1484
1485 if (!RAND_status())
7199e1ee 1486 return tls_error(US"RAND_status", host,
cf0c6164 1487 US"unable to seed random number generator", errstr);
059ec3d9
PH
1488 }
1489
1490/* Set up the information callback, which outputs if debugging is at a suitable
1491level. */
1492
7006ee24 1493DEBUG(D_tls) SSL_CTX_set_info_callback(ctx, (void (*)())info_callback);
059ec3d9 1494
c80c5570 1495/* Automatically re-try reads/writes after renegotiation. */
7006ee24 1496(void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
c80c5570 1497
77bb000f
PP
1498/* Apply administrator-supplied work-arounds.
1499Historically we applied just one requested option,
1500SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we
1501moved to an administrator-controlled list of options to specify and
1502grandfathered in the first one as the default value for "openssl_options".
059ec3d9 1503
77bb000f
PP
1504No OpenSSL version number checks: the options we accept depend upon the
1505availability of the option value macros from OpenSSL. */
059ec3d9 1506
7006ee24 1507if (!tls_openssl_options_parse(openssl_options, &init_options))
cf0c6164 1508 return tls_error(US"openssl_options parsing failed", host, NULL, errstr);
77bb000f
PP
1509
1510if (init_options)
1511 {
1512 DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options);
7006ee24 1513 if (!(SSL_CTX_set_options(ctx, init_options)))
77bb000f 1514 return tls_error(string_sprintf(
cf0c6164 1515 "SSL_CTX_set_option(%#lx)", init_options), host, NULL, errstr);
77bb000f
PP
1516 }
1517else
1518 DEBUG(D_tls) debug_printf("no SSL CTX options to set\n");
059ec3d9 1519
7006ee24
JH
1520/* Disable session cache unconditionally */
1521
1522(void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
1523
059ec3d9 1524/* Initialize with DH parameters if supplied */
10ca4f1c 1525/* Initialize ECDH temp key parameter selection */
059ec3d9 1526
7006ee24
JH
1527if ( !init_dh(ctx, dhparam, host, errstr)
1528 || !init_ecdh(ctx, host, errstr)
038597d2
PP
1529 )
1530 return DEFER;
059ec3d9 1531
3f7eeb86 1532/* Set up certificate and key (and perhaps OCSP info) */
059ec3d9 1533
7006ee24 1534if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK)
23bb6982 1535 return rc;
c91535f3 1536
c3033f13
JH
1537/* If we need to handle SNI or OCSP, do so */
1538
3bcbbbe2 1539#ifdef EXIM_HAVE_OPENSSL_TLSEXT
c3033f13
JH
1540# ifndef DISABLE_OCSP
1541 if (!(cbinfo->verify_stack = sk_X509_new_null()))
1542 {
1543 DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n");
1544 return FAIL;
1545 }
1546# endif
1547
f5d78688 1548if (host == NULL) /* server */
3f0945ff 1549 {
f2de3a33 1550# ifndef DISABLE_OCSP
f5d78688 1551 /* We check u_ocsp.server.file, not server.response, because we care about if
3f7eeb86
PP
1552 the option exists, not what the current expansion might be, as SNI might
1553 change the certificate and OCSP file in use between now and the time the
1554 callback is invoked. */
f5d78688 1555 if (cbinfo->u_ocsp.server.file)
3f7eeb86 1556 {
7006ee24
JH
1557 SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb);
1558 SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
3f7eeb86 1559 }
f5d78688 1560# endif
3f0945ff
PP
1561 /* We always do this, so that $tls_sni is available even if not used in
1562 tls_certificate */
7006ee24
JH
1563 SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb);
1564 SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo);
3f0945ff 1565 }
f2de3a33 1566# ifndef DISABLE_OCSP
f5d78688
JH
1567else /* client */
1568 if(ocsp_file) /* wanting stapling */
1569 {
1570 if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new()))
1571 {
1572 DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n");
1573 return FAIL;
1574 }
7006ee24
JH
1575 SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb);
1576 SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
f5d78688
JH
1577 }
1578# endif
7be682ca 1579#endif
059ec3d9 1580
e51c7be2 1581cbinfo->verify_cert_hostnames = NULL;
e51c7be2 1582
c8dfb21d 1583#ifdef EXIM_HAVE_EPHEM_RSA_KEX
059ec3d9 1584/* Set up the RSA callback */
7006ee24 1585SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback);
c8dfb21d 1586#endif
059ec3d9
PH
1587
1588/* Finally, set the timeout, and we are done */
1589
7006ee24 1590SSL_CTX_set_timeout(ctx, ssl_session_timeout);
059ec3d9 1591DEBUG(D_tls) debug_printf("Initialized TLS\n");
7be682ca 1592
817d9f57 1593*cbp = cbinfo;
7006ee24 1594*ctxp = ctx;
7be682ca 1595
059ec3d9
PH
1596return OK;
1597}
1598
1599
1600
1601
1602/*************************************************
1603* Get name of cipher in use *
1604*************************************************/
1605
817d9f57 1606/*
059ec3d9 1607Argument: pointer to an SSL structure for the connection
817d9f57
JH
1608 buffer to use for answer
1609 size of buffer
1610 pointer to number of bits for cipher
059ec3d9
PH
1611Returns: nothing
1612*/
1613
1614static void
817d9f57 1615construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits)
059ec3d9 1616{
57b3a7f5
PP
1617/* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't
1618yet reflect that. It should be a safe change anyway, even 0.9.8 versions have
1619the accessor functions use const in the prototype. */
1620const SSL_CIPHER *c;
d9784128 1621const uschar *ver;
059ec3d9 1622
d9784128 1623ver = (const uschar *)SSL_get_version(ssl);
059ec3d9 1624
57b3a7f5 1625c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl);
817d9f57 1626SSL_CIPHER_get_bits(c, bits);
059ec3d9 1627
817d9f57
JH
1628string_format(cipherbuf, bsize, "%s:%s:%u", ver,
1629 SSL_CIPHER_get_name(c), *bits);
059ec3d9
PH
1630
1631DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf);
1632}
1633
1634
f69979cf
JH
1635static void
1636peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned bsize)
1637{
1638/*XXX we might consider a list-of-certs variable for the cert chain.
1639SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support
1640in list-handling functions, also consider the difference between the entire
1641chain and the elements sent by the peer. */
1642
1643/* Will have already noted peercert on a verify fail; possibly not the leaf */
1644if (!tlsp->peercert)
1645 tlsp->peercert = SSL_get_peer_certificate(ssl);
1646/* Beware anonymous ciphers which lead to server_cert being NULL */
1647if (tlsp->peercert)
1648 {
1649 X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, bsize);
1650 peerdn[bsize-1] = '\0';
1651 tlsp->peerdn = peerdn; /*XXX a static buffer... */
1652 }
1653else
1654 tlsp->peerdn = NULL;
1655}
1656
1657
059ec3d9
PH
1658
1659
1660
1661/*************************************************
1662* Set up for verifying certificates *
1663*************************************************/
1664
c3033f13
JH
1665/* Load certs from file, return TRUE on success */
1666
1667static BOOL
1668chain_from_pem_file(const uschar * file, STACK_OF(X509) * verify_stack)
1669{
1670BIO * bp;
1671X509 * x;
1672
1673if (!(bp = BIO_new_file(CS file, "r"))) return FALSE;
1674while ((x = PEM_read_bio_X509(bp, NULL, 0, NULL)))
1675 sk_X509_push(verify_stack, x);
1676BIO_free(bp);
1677return TRUE;
1678}
1679
1680
1681
059ec3d9
PH
1682/* Called by both client and server startup
1683
1684Arguments:
7be682ca 1685 sctx SSL_CTX* to initialise
059ec3d9
PH
1686 certs certs file or NULL
1687 crl CRL file or NULL
1688 host NULL in a server; the remote host in a client
1689 optional TRUE if called from a server for a host in tls_try_verify_hosts;
1690 otherwise passed as FALSE
983207c1 1691 cert_vfy_cb Callback function for certificate verification
cf0c6164 1692 errstr error string pointer
059ec3d9
PH
1693
1694Returns: OK/DEFER/FAIL
1695*/
1696
1697static int
983207c1 1698setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
cf0c6164 1699 int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr)
059ec3d9
PH
1700{
1701uschar *expcerts, *expcrl;
1702
cf0c6164 1703if (!expand_check(certs, US"tls_verify_certificates", &expcerts, errstr))
059ec3d9 1704 return DEFER;
57cc2785 1705DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts);
059ec3d9 1706
10a831a3 1707if (expcerts && *expcerts)
059ec3d9 1708 {
10a831a3
JH
1709 /* Tell the library to use its compiled-in location for the system default
1710 CA bundle. Then add the ones specified in the config, if any. */
cb1d7830 1711
10a831a3 1712 if (!SSL_CTX_set_default_verify_paths(sctx))
cf0c6164 1713 return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr);
10a831a3
JH
1714
1715 if (Ustrcmp(expcerts, "system") != 0)
059ec3d9 1716 {
cb1d7830
JH
1717 struct stat statbuf;
1718
cb1d7830
JH
1719 if (Ustat(expcerts, &statbuf) < 0)
1720 {
1721 log_write(0, LOG_MAIN|LOG_PANIC,
1722 "failed to stat %s for certificates", expcerts);
1723 return DEFER;
1724 }
059ec3d9 1725 else
059ec3d9 1726 {
cb1d7830
JH
1727 uschar *file, *dir;
1728 if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
1729 { file = NULL; dir = expcerts; }
1730 else
c3033f13
JH
1731 {
1732 file = expcerts; dir = NULL;
1733#ifndef DISABLE_OCSP
1734 /* In the server if we will be offering an OCSP proof, load chain from
1735 file for verifying the OCSP proof at load time. */
1736
1737 if ( !host
1738 && statbuf.st_size > 0
1739 && server_static_cbinfo->u_ocsp.server.file
1740 && !chain_from_pem_file(file, server_static_cbinfo->verify_stack)
1741 )
1742 {
1743 log_write(0, LOG_MAIN|LOG_PANIC,
1744 "failed to load cert hain from %s", file);
1745 return DEFER;
1746 }
1747#endif
1748 }
cb1d7830
JH
1749
1750 /* If a certificate file is empty, the next function fails with an
1751 unhelpful error message. If we skip it, we get the correct behaviour (no
1752 certificates are recognized, but the error message is still misleading (it
c3033f13 1753 says no certificate was supplied). But this is better. */
cb1d7830 1754
f2f2c91b
JH
1755 if ( (!file || statbuf.st_size > 0)
1756 && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir))
cf0c6164 1757 return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr);
cb1d7830
JH
1758
1759 /* Load the list of CAs for which we will accept certs, for sending
1760 to the client. This is only for the one-file tls_verify_certificates
1761 variant.
1762 If a list isn't loaded into the server, but
1763 some verify locations are set, the server end appears to make
4c04137d 1764 a wildcard request for client certs.
10a831a3 1765 Meanwhile, the client library as default behaviour *ignores* the list
cb1d7830
JH
1766 we send over the wire - see man SSL_CTX_set_client_cert_cb.
1767 Because of this, and that the dir variant is likely only used for
1768 the public-CA bundle (not for a private CA), not worth fixing.
1769 */
f2f2c91b 1770 if (file)
cb1d7830
JH
1771 {
1772 STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file);
f2f2c91b
JH
1773
1774 DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n",
cb1d7830
JH
1775 sk_X509_NAME_num(names));
1776 SSL_CTX_set_client_CA_list(sctx, names);
1777 }
059ec3d9
PH
1778 }
1779 }
1780
1781 /* Handle a certificate revocation list. */
1782
10a831a3 1783#if OPENSSL_VERSION_NUMBER > 0x00907000L
059ec3d9 1784
8b417f2c 1785 /* This bit of code is now the version supplied by Lars Mainka. (I have
10a831a3 1786 merely reformatted it into the Exim code style.)
8b417f2c 1787
10a831a3
JH
1788 "From here I changed the code to add support for multiple crl's
1789 in pem format in one file or to support hashed directory entries in
1790 pem format instead of a file. This method now uses the library function
1791 X509_STORE_load_locations to add the CRL location to the SSL context.
1792 OpenSSL will then handle the verify against CA certs and CRLs by
1793 itself in the verify callback." */
8b417f2c 1794
cf0c6164 1795 if (!expand_check(crl, US"tls_crl", &expcrl, errstr)) return DEFER;
10a831a3 1796 if (expcrl && *expcrl)
059ec3d9 1797 {
8b417f2c
PH
1798 struct stat statbufcrl;
1799 if (Ustat(expcrl, &statbufcrl) < 0)
1800 {
1801 log_write(0, LOG_MAIN|LOG_PANIC,
1802 "failed to stat %s for certificates revocation lists", expcrl);
1803 return DEFER;
1804 }
1805 else
059ec3d9 1806 {
8b417f2c
PH
1807 /* is it a file or directory? */
1808 uschar *file, *dir;
7be682ca 1809 X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx);
8b417f2c 1810 if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR)
059ec3d9 1811 {
8b417f2c
PH
1812 file = NULL;
1813 dir = expcrl;
1814 DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir);
059ec3d9
PH
1815 }
1816 else
1817 {
8b417f2c
PH
1818 file = expcrl;
1819 dir = NULL;
1820 DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file);
059ec3d9 1821 }
8b417f2c 1822 if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0)
cf0c6164 1823 return tls_error(US"X509_STORE_load_locations", host, NULL, errstr);
8b417f2c
PH
1824
1825 /* setting the flags to check against the complete crl chain */
1826
1827 X509_STORE_set_flags(cvstore,
1828 X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
059ec3d9 1829 }
059ec3d9
PH
1830 }
1831
10a831a3 1832#endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
059ec3d9
PH
1833
1834 /* If verification is optional, don't fail if no certificate */
1835
7be682ca 1836 SSL_CTX_set_verify(sctx,
059ec3d9 1837 SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT),
983207c1 1838 cert_vfy_cb);
059ec3d9
PH
1839 }
1840
1841return OK;
1842}
1843
1844
1845
1846/*************************************************
1847* Start a TLS session in a server *
1848*************************************************/
1849
1850/* This is called when Exim is running as a server, after having received
1851the STARTTLS command. It must respond to that command, and then negotiate
1852a TLS session.
1853
1854Arguments:
1855 require_ciphers allowed ciphers
cf0c6164 1856 errstr pointer to error message
059ec3d9
PH
1857
1858Returns: OK on success
1859 DEFER for errors before the start of the negotiation
4c04137d 1860 FAIL for errors during the negotiation; the server can't
059ec3d9
PH
1861 continue running.
1862*/
1863
1864int
cf0c6164 1865tls_server_start(const uschar * require_ciphers, uschar ** errstr)
059ec3d9
PH
1866{
1867int rc;
cf0c6164
JH
1868uschar * expciphers;
1869tls_ext_ctx_cb * cbinfo;
f69979cf 1870static uschar peerdn[256];
817d9f57 1871static uschar cipherbuf[256];
059ec3d9
PH
1872
1873/* Check for previous activation */
1874
817d9f57 1875if (tls_in.active >= 0)
059ec3d9 1876 {
cf0c6164 1877 tls_error(US"STARTTLS received after TLS started", NULL, US"", errstr);
059ec3d9
PH
1878 smtp_printf("554 Already in TLS\r\n");
1879 return FAIL;
1880 }
1881
1882/* Initialize the SSL library. If it fails, it will already have logged
1883the error. */
1884
817d9f57 1885rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey,
f2de3a33 1886#ifndef DISABLE_OCSP
3f7eeb86
PP
1887 tls_ocsp_file,
1888#endif
cf0c6164 1889 NULL, &server_static_cbinfo, errstr);
059ec3d9 1890if (rc != OK) return rc;
817d9f57 1891cbinfo = server_static_cbinfo;
059ec3d9 1892
cf0c6164 1893if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr))
059ec3d9
PH
1894 return FAIL;
1895
1896/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
17c76198
PP
1897were historically separated by underscores. So that I can use either form in my
1898tests, and also for general convenience, we turn underscores into hyphens here.
1899*/
059ec3d9 1900
c3033f13 1901if (expciphers)
059ec3d9 1902 {
c3033f13 1903 uschar * s = expciphers;
059ec3d9
PH
1904 while (*s != 0) { if (*s == '_') *s = '-'; s++; }
1905 DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
817d9f57 1906 if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers))
cf0c6164 1907 return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr);
7be682ca 1908 cbinfo->server_cipher_list = expciphers;
059ec3d9
PH
1909 }
1910
1911/* If this is a host for which certificate verification is mandatory or
1912optional, set up appropriately. */
1913
817d9f57 1914tls_in.certificate_verified = FALSE;
53a7196b
JH
1915#ifdef EXPERIMENTAL_DANE
1916tls_in.dane_verified = FALSE;
1917#endif
a2ff477a 1918server_verify_callback_called = FALSE;
059ec3d9
PH
1919
1920if (verify_check_host(&tls_verify_hosts) == OK)
1921 {
983207c1 1922 rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
cf0c6164 1923 FALSE, verify_callback_server, errstr);
059ec3d9 1924 if (rc != OK) return rc;
a2ff477a 1925 server_verify_optional = FALSE;
059ec3d9
PH
1926 }
1927else if (verify_check_host(&tls_try_verify_hosts) == OK)
1928 {
983207c1 1929 rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
cf0c6164 1930 TRUE, verify_callback_server, errstr);
059ec3d9 1931 if (rc != OK) return rc;
a2ff477a 1932 server_verify_optional = TRUE;
059ec3d9
PH
1933 }
1934
1935/* Prepare for new connection */
1936
cf0c6164
JH
1937if (!(server_ssl = SSL_new(server_ctx)))
1938 return tls_error(US"SSL_new", NULL, NULL, errstr);
da3ad30d
PP
1939
1940/* Warning: we used to SSL_clear(ssl) here, it was removed.
1941 *
1942 * With the SSL_clear(), we get strange interoperability bugs with
1943 * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in
1944 * OpenSSL itself, as a clear should not lead to inability to follow protocols.
1945 *
1946 * The SSL_clear() call is to let an existing SSL* be reused, typically after
1947 * session shutdown. In this case, we have a brand new object and there's no
1948 * obvious reason to immediately clear it. I'm guessing that this was
1949 * originally added because of incomplete initialisation which the clear fixed,
1950 * in some historic release.
1951 */
059ec3d9
PH
1952
1953/* Set context and tell client to go ahead, except in the case of TLS startup
1954on connection, where outputting anything now upsets the clients and tends to
1955make them disconnect. We need to have an explicit fflush() here, to force out
1956the response. Other smtp_printf() calls do not need it, because in non-TLS
1957mode, the fflush() happens when smtp_getc() is called. */
1958
817d9f57
JH
1959SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx));
1960if (!tls_in.on_connect)
059ec3d9
PH
1961 {
1962 smtp_printf("220 TLS go ahead\r\n");
1963 fflush(smtp_out);
1964 }
1965
1966/* Now negotiate the TLS session. We put our own timer on it, since it seems
1967that the OpenSSL library doesn't. */
1968
817d9f57
JH
1969SSL_set_wfd(server_ssl, fileno(smtp_out));
1970SSL_set_rfd(server_ssl, fileno(smtp_in));
1971SSL_set_accept_state(server_ssl);
059ec3d9
PH
1972
1973DEBUG(D_tls) debug_printf("Calling SSL_accept\n");
1974
1975sigalrm_seen = FALSE;
1976if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
817d9f57 1977rc = SSL_accept(server_ssl);
059ec3d9
PH
1978alarm(0);
1979
1980if (rc <= 0)
1981 {
cf0c6164 1982 (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr);
059ec3d9
PH
1983 return FAIL;
1984 }
1985
1986DEBUG(D_tls) debug_printf("SSL_accept was successful\n");
1987
1988/* TLS has been set up. Adjust the input functions to read via TLS,
1989and initialize things. */
1990
f69979cf
JH
1991peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn));
1992
817d9f57
JH
1993construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits);
1994tls_in.cipher = cipherbuf;
059ec3d9
PH
1995
1996DEBUG(D_tls)
1997 {
1998 uschar buf[2048];
817d9f57 1999 if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL)
059ec3d9
PH
2000 debug_printf("Shared ciphers: %s\n", buf);
2001 }
2002
9d1c15ef
JH
2003/* Record the certificate we presented */
2004 {
2005 X509 * crt = SSL_get_certificate(server_ssl);
2006 tls_in.ourcert = crt ? X509_dup(crt) : NULL;
2007 }
059ec3d9 2008
817d9f57
JH
2009/* Only used by the server-side tls (tls_in), including tls_getc.
2010 Client-side (tls_out) reads (seem to?) go via
2011 smtp_read_response()/ip_recv().
2012 Hence no need to duplicate for _in and _out.
2013 */
059ec3d9
PH
2014ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size);
2015ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0;
2016ssl_xfer_eof = ssl_xfer_error = 0;
2017
2018receive_getc = tls_getc;
584e96c6 2019receive_get_cache = tls_get_cache;
059ec3d9
PH
2020receive_ungetc = tls_ungetc;
2021receive_feof = tls_feof;
2022receive_ferror = tls_ferror;
58eb016e 2023receive_smtp_buffered = tls_smtp_buffered;
059ec3d9 2024
817d9f57 2025tls_in.active = fileno(smtp_out);
059ec3d9
PH
2026return OK;
2027}
2028
2029
2030
2031
043b1248
JH
2032static int
2033tls_client_basic_ctx_init(SSL_CTX * ctx,
cf0c6164
JH
2034 host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo,
2035 uschar ** errstr)
043b1248
JH
2036{
2037int rc;
94431adb 2038/* stick to the old behaviour for compatibility if tls_verify_certificates is
043b1248
JH
2039 set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only
2040 the specified host patterns if one of them is defined */
2041
610ff438
JH
2042if ( ( !ob->tls_verify_hosts
2043 && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts)
2044 )
5130845b 2045 || (verify_check_given_host(&ob->tls_verify_hosts, host) == OK)
aa2a70ba 2046 )
043b1248 2047 client_verify_optional = FALSE;
5130845b 2048else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK)
aa2a70ba
JH
2049 client_verify_optional = TRUE;
2050else
2051 return OK;
2052
2053if ((rc = setup_certs(ctx, ob->tls_verify_certificates,
cf0c6164
JH
2054 ob->tls_crl, host, client_verify_optional, verify_callback_client,
2055 errstr)) != OK)
aa2a70ba 2056 return rc;
043b1248 2057
5130845b 2058if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK)
043b1248 2059 {
4af0d74a 2060 cbinfo->verify_cert_hostnames =
8c5d388a 2061#ifdef SUPPORT_I18N
4af0d74a
JH
2062 string_domain_utf8_to_alabel(host->name, NULL);
2063#else
2064 host->name;
2065#endif
aa2a70ba
JH
2066 DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n",
2067 cbinfo->verify_cert_hostnames);
043b1248 2068 }
043b1248
JH
2069return OK;
2070}
059ec3d9 2071
fde080a4
JH
2072
2073#ifdef EXPERIMENTAL_DANE
2074static int
cf0c6164 2075dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa, uschar ** errstr)
fde080a4
JH
2076{
2077dns_record * rr;
2078dns_scan dnss;
2079const char * hostnames[2] = { CS host->name, NULL };
2080int found = 0;
2081
2082if (DANESSL_init(ssl, NULL, hostnames) != 1)
cf0c6164 2083 return tls_error(US"hostnames load", host, NULL, errstr);
fde080a4
JH
2084
2085for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
2086 rr;
2087 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)
2088 ) if (rr->type == T_TLSA)
2089 {
c3033f13 2090 const uschar * p = rr->data;
fde080a4
JH
2091 uint8_t usage, selector, mtype;
2092 const char * mdname;
2093
fde080a4 2094 usage = *p++;
133d2546
JH
2095
2096 /* Only DANE-TA(2) and DANE-EE(3) are supported */
2097 if (usage != 2 && usage != 3) continue;
2098
fde080a4
JH
2099 selector = *p++;
2100 mtype = *p++;
2101
2102 switch (mtype)
2103 {
133d2546
JH
2104 default: continue; /* Only match-types 0, 1, 2 are supported */
2105 case 0: mdname = NULL; break;
2106 case 1: mdname = "sha256"; break;
2107 case 2: mdname = "sha512"; break;
fde080a4
JH
2108 }
2109
133d2546 2110 found++;
fde080a4
JH
2111 switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3))
2112 {
2113 default:
cf0c6164 2114 return tls_error(US"tlsa load", host, NULL, errstr);
c035b645 2115 case 0: /* action not taken */
fde080a4
JH
2116 case 1: break;
2117 }
594706ea
JH
2118
2119 tls_out.tlsa_usage |= 1<<usage;
fde080a4
JH
2120 }
2121
2122if (found)
2123 return OK;
2124
133d2546 2125log_write(0, LOG_MAIN, "DANE error: No usable TLSA records");
6ebd79ec 2126return DEFER;
fde080a4
JH
2127}
2128#endif /*EXPERIMENTAL_DANE*/
2129
2130
2131
059ec3d9
PH
2132/*************************************************
2133* Start a TLS session in a client *
2134*************************************************/
2135
2136/* Called from the smtp transport after STARTTLS has been accepted.
2137
2138Argument:
2139 fd the fd of the connection
2140 host connected host (for messages)
83da1223 2141 addr the first address
a7538db1 2142 tb transport (always smtp)
0e66b3b6 2143 tlsa_dnsa tlsa lookup, if DANE, else null
cf0c6164 2144 errstr error string pointer
059ec3d9
PH
2145
2146Returns: OK on success
2147 FAIL otherwise - note that tls_error() will not give DEFER
2148 because this is not a server
2149*/
2150
2151int
f5d78688 2152tls_client_start(int fd, host_item *host, address_item *addr,
cf0c6164 2153 transport_instance * tb,
0e66b3b6 2154#ifdef EXPERIMENTAL_DANE
cf0c6164 2155 dns_answer * tlsa_dnsa,
0e66b3b6 2156#endif
cf0c6164 2157 uschar ** errstr)
059ec3d9 2158{
a7538db1
JH
2159smtp_transport_options_block * ob =
2160 (smtp_transport_options_block *)tb->options_block;
f69979cf 2161static uschar peerdn[256];
868f5672 2162uschar * expciphers;
059ec3d9 2163int rc;
817d9f57 2164static uschar cipherbuf[256];
043b1248
JH
2165
2166#ifndef DISABLE_OCSP
043b1248 2167BOOL request_ocsp = FALSE;
6634ac8d 2168BOOL require_ocsp = FALSE;
043b1248 2169#endif
043b1248
JH
2170
2171#ifdef EXPERIMENTAL_DANE
594706ea 2172tls_out.tlsa_usage = 0;
043b1248
JH
2173#endif
2174
f2de3a33 2175#ifndef DISABLE_OCSP
043b1248 2176 {
4f59c424
JH
2177# ifdef EXPERIMENTAL_DANE
2178 if ( tlsa_dnsa
2179 && ob->hosts_request_ocsp[0] == '*'
2180 && ob->hosts_request_ocsp[1] == '\0'
2181 )
2182 {
2183 /* Unchanged from default. Use a safer one under DANE */
2184 request_ocsp = TRUE;
2185 ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} "
2186 " {= {4}{$tls_out_tlsa_usage}} } "
2187 " {*}{}}";
2188 }
2189# endif
2190
5130845b
JH
2191 if ((require_ocsp =
2192 verify_check_given_host(&ob->hosts_require_ocsp, host) == OK))
fca41d5a
JH
2193 request_ocsp = TRUE;
2194 else
fca41d5a 2195# ifdef EXPERIMENTAL_DANE
4f59c424 2196 if (!request_ocsp)
fca41d5a 2197# endif
5130845b
JH
2198 request_ocsp =
2199 verify_check_given_host(&ob->hosts_request_ocsp, host) == OK;
043b1248 2200 }
f5d78688 2201#endif
059ec3d9 2202
65867078
JH
2203rc = tls_init(&client_ctx, host, NULL,
2204 ob->tls_certificate, ob->tls_privatekey,
f2de3a33 2205#ifndef DISABLE_OCSP
44662487 2206 (void *)(long)request_ocsp,
3f7eeb86 2207#endif
cf0c6164 2208 addr, &client_static_cbinfo, errstr);
059ec3d9
PH
2209if (rc != OK) return rc;
2210
817d9f57 2211tls_out.certificate_verified = FALSE;
a2ff477a 2212client_verify_callback_called = FALSE;
059ec3d9 2213
65867078 2214if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers",
cf0c6164 2215 &expciphers, errstr))
059ec3d9
PH
2216 return FAIL;
2217
2218/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
2219are separated by underscores. So that I can use either form in my tests, and
2220also for general convenience, we turn underscores into hyphens here. */
2221
cf0c6164 2222if (expciphers)
059ec3d9
PH
2223 {
2224 uschar *s = expciphers;
cf0c6164 2225 while (*s) { if (*s == '_') *s = '-'; s++; }
059ec3d9 2226 DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
817d9f57 2227 if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers))
cf0c6164 2228 return tls_error(US"SSL_CTX_set_cipher_list", host, NULL, errstr);
059ec3d9
PH
2229 }
2230
043b1248 2231#ifdef EXPERIMENTAL_DANE
0e66b3b6 2232if (tlsa_dnsa)
a63be306 2233 {
02af313d
JH
2234 SSL_CTX_set_verify(client_ctx,
2235 SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
2236 verify_callback_client_dane);
e5cccda9 2237
043b1248 2238 if (!DANESSL_library_init())
cf0c6164 2239 return tls_error(US"library init", host, NULL, errstr);
043b1248 2240 if (DANESSL_CTX_init(client_ctx) <= 0)
cf0c6164 2241 return tls_error(US"context init", host, NULL, errstr);
043b1248
JH
2242 }
2243else
e51c7be2 2244
043b1248
JH
2245#endif
2246
cf0c6164
JH
2247 if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob,
2248 client_static_cbinfo, errstr)) != OK)
65867078 2249 return rc;
059ec3d9 2250
65867078 2251if ((client_ssl = SSL_new(client_ctx)) == NULL)
cf0c6164 2252 return tls_error(US"SSL_new", host, NULL, errstr);
817d9f57
JH
2253SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx));
2254SSL_set_fd(client_ssl, fd);
2255SSL_set_connect_state(client_ssl);
059ec3d9 2256
65867078 2257if (ob->tls_sni)
3f0945ff 2258 {
cf0c6164 2259 if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni, errstr))
3f0945ff 2260 return FAIL;
cf0c6164 2261 if (!tls_out.sni)
2c9a0e86
PP
2262 {
2263 DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n");
2264 }
ec4b68e5 2265 else if (!Ustrlen(tls_out.sni))
817d9f57 2266 tls_out.sni = NULL;
3f0945ff
PP
2267 else
2268 {
35731706 2269#ifdef EXIM_HAVE_OPENSSL_TLSEXT
817d9f57
JH
2270 DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni);
2271 SSL_set_tlsext_host_name(client_ssl, tls_out.sni);
35731706 2272#else
66802652 2273 log_write(0, LOG_MAIN, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n",
02d9264f 2274 tls_out.sni);
35731706 2275#endif
3f0945ff
PP
2276 }
2277 }
2278
594706ea 2279#ifdef EXPERIMENTAL_DANE
0e66b3b6 2280if (tlsa_dnsa)
cf0c6164 2281 if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa, errstr)) != OK)
594706ea
JH
2282 return rc;
2283#endif
2284
f2de3a33 2285#ifndef DISABLE_OCSP
f5d78688
JH
2286/* Request certificate status at connection-time. If the server
2287does OCSP stapling we will get the callback (set in tls_init()) */
b50c8b84 2288# ifdef EXPERIMENTAL_DANE
44662487
JH
2289if (request_ocsp)
2290 {
594706ea 2291 const uschar * s;
41afb5cb
JH
2292 if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage"))
2293 || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage"))
594706ea
JH
2294 )
2295 { /* Re-eval now $tls_out_tlsa_usage is populated. If
2296 this means we avoid the OCSP request, we wasted the setup
2297 cost in tls_init(). */
5130845b
JH
2298 require_ocsp = verify_check_given_host(&ob->hosts_require_ocsp, host) == OK;
2299 request_ocsp = require_ocsp
2300 || verify_check_given_host(&ob->hosts_request_ocsp, host) == OK;
594706ea
JH
2301 }
2302 }
b50c8b84
JH
2303# endif
2304
594706ea
JH
2305if (request_ocsp)
2306 {
f5d78688 2307 SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp);
44662487
JH
2308 client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp;
2309 tls_out.ocsp = OCSP_NOT_RESP;
2310 }
f5d78688
JH
2311#endif
2312
0cbf2b82 2313#ifndef DISABLE_EVENT
774ef2d7 2314client_static_cbinfo->event_action = tb->event_action;
a7538db1 2315#endif
043b1248 2316
059ec3d9
PH
2317/* There doesn't seem to be a built-in timeout on connection. */
2318
2319DEBUG(D_tls) debug_printf("Calling SSL_connect\n");
2320sigalrm_seen = FALSE;
65867078 2321alarm(ob->command_timeout);
817d9f57 2322rc = SSL_connect(client_ssl);
059ec3d9
PH
2323alarm(0);
2324
043b1248 2325#ifdef EXPERIMENTAL_DANE
0e66b3b6 2326if (tlsa_dnsa)
fde080a4 2327 DANESSL_cleanup(client_ssl);
043b1248
JH
2328#endif
2329
059ec3d9 2330if (rc <= 0)
cf0c6164
JH
2331 return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL,
2332 errstr);
059ec3d9
PH
2333
2334DEBUG(D_tls) debug_printf("SSL_connect succeeded\n");
2335
f69979cf 2336peer_cert(client_ssl, &tls_out, peerdn, sizeof(peerdn));
059ec3d9 2337
817d9f57
JH
2338construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits);
2339tls_out.cipher = cipherbuf;
059ec3d9 2340
9d1c15ef
JH
2341/* Record the certificate we presented */
2342 {
2343 X509 * crt = SSL_get_certificate(client_ssl);
2344 tls_out.ourcert = crt ? X509_dup(crt) : NULL;
2345 }
2346
817d9f57 2347tls_out.active = fd;
059ec3d9
PH
2348return OK;
2349}
2350
2351
2352
2353
2354
2355/*************************************************
2356* TLS version of getc *
2357*************************************************/
2358
2359/* This gets the next byte from the TLS input buffer. If the buffer is empty,
2360it refills the buffer via the SSL reading function.
2361
bd8fbe36 2362Arguments: lim Maximum amount to read/buffer
059ec3d9 2363Returns: the next character or EOF
817d9f57
JH
2364
2365Only used by the server-side TLS.
059ec3d9
PH
2366*/
2367
2368int
bd8fbe36 2369tls_getc(unsigned lim)
059ec3d9
PH
2370{
2371if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm)
2372 {
2373 int error;
2374 int inbytes;
2375
817d9f57 2376 DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl,
c80c5570 2377 ssl_xfer_buffer, ssl_xfer_buffer_size);
059ec3d9
PH
2378
2379 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
bd8fbe36
JH
2380 inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer,
2381 MIN(ssl_xfer_buffer_size, lim));
817d9f57 2382 error = SSL_get_error(server_ssl, inbytes);
059ec3d9
PH
2383 alarm(0);
2384
2385 /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been
2386 closed down, not that the socket itself has been closed down. Revert to
2387 non-SSL handling. */
2388
2389 if (error == SSL_ERROR_ZERO_RETURN)
2390 {
2391 DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
2392
2393 receive_getc = smtp_getc;
584e96c6 2394 receive_get_cache = smtp_get_cache;
059ec3d9
PH
2395 receive_ungetc = smtp_ungetc;
2396 receive_feof = smtp_feof;
2397 receive_ferror = smtp_ferror;
58eb016e 2398 receive_smtp_buffered = smtp_buffered;
059ec3d9 2399
817d9f57
JH
2400 SSL_free(server_ssl);
2401 server_ssl = NULL;
2402 tls_in.active = -1;
2403 tls_in.bits = 0;
2404 tls_in.cipher = NULL;
2405 tls_in.peerdn = NULL;
2406 tls_in.sni = NULL;
059ec3d9 2407
bd8fbe36 2408 return smtp_getc(lim);
059ec3d9
PH
2409 }
2410
2411 /* Handle genuine errors */
2412
ba084640
PP
2413 else if (error == SSL_ERROR_SSL)
2414 {
2415 ERR_error_string(ERR_get_error(), ssl_errstring);
89dd51cd 2416 log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring);
ba084640
PP
2417 ssl_xfer_error = 1;
2418 return EOF;
2419 }
2420
059ec3d9
PH
2421 else if (error != SSL_ERROR_NONE)
2422 {
2423 DEBUG(D_tls) debug_printf("Got SSL error %d\n", error);
2424 ssl_xfer_error = 1;
2425 return EOF;
2426 }
c80c5570 2427
80a47a2c
TK
2428#ifndef DISABLE_DKIM
2429 dkim_exim_verify_feed(ssl_xfer_buffer, inbytes);
2430#endif
059ec3d9
PH
2431 ssl_xfer_buffer_hwm = inbytes;
2432 ssl_xfer_buffer_lwm = 0;
2433 }
2434
2435/* Something in the buffer; return next uschar */
2436
2437return ssl_xfer_buffer[ssl_xfer_buffer_lwm++];
2438}
2439
584e96c6
JH
2440void
2441tls_get_cache()
2442{
9960d1e5 2443#ifndef DISABLE_DKIM
584e96c6
JH
2444int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm;
2445if (n > 0)
2446 dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n);
584e96c6 2447#endif
9960d1e5 2448}
584e96c6 2449
059ec3d9
PH
2450
2451
2452/*************************************************
2453* Read bytes from TLS channel *
2454*************************************************/
2455
2456/*
2457Arguments:
2458 buff buffer of data
2459 len size of buffer
2460
2461Returns: the number of bytes read
2462 -1 after a failed read
817d9f57
JH
2463
2464Only used by the client-side TLS.
059ec3d9
PH
2465*/
2466
2467int
389ca47a 2468tls_read(BOOL is_server, uschar *buff, size_t len)
059ec3d9 2469{
389ca47a 2470SSL *ssl = is_server ? server_ssl : client_ssl;
059ec3d9
PH
2471int inbytes;
2472int error;
2473
389ca47a 2474DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl,
c80c5570 2475 buff, (unsigned int)len);
059ec3d9 2476
389ca47a
JH
2477inbytes = SSL_read(ssl, CS buff, len);
2478error = SSL_get_error(ssl, inbytes);
059ec3d9
PH
2479
2480if (error == SSL_ERROR_ZERO_RETURN)
2481 {
2482 DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
2483 return -1;
2484 }
2485else if (error != SSL_ERROR_NONE)
059ec3d9 2486 return -1;
059ec3d9
PH
2487
2488return inbytes;
2489}
2490
2491
2492
2493
2494
2495/*************************************************
2496* Write bytes down TLS channel *
2497*************************************************/
2498
2499/*
2500Arguments:
817d9f57 2501 is_server channel specifier
059ec3d9
PH
2502 buff buffer of data
2503 len number of bytes
2504
2505Returns: the number of bytes after a successful write,
2506 -1 after a failed write
817d9f57
JH
2507
2508Used by both server-side and client-side TLS.
059ec3d9
PH
2509*/
2510
2511int
817d9f57 2512tls_write(BOOL is_server, const uschar *buff, size_t len)
059ec3d9
PH
2513{
2514int outbytes;
2515int error;
2516int left = len;
817d9f57 2517SSL *ssl = is_server ? server_ssl : client_ssl;
059ec3d9 2518
c80c5570 2519DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left);
059ec3d9
PH
2520while (left > 0)
2521 {
c80c5570 2522 DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left);
059ec3d9
PH
2523 outbytes = SSL_write(ssl, CS buff, left);
2524 error = SSL_get_error(ssl, outbytes);
2525 DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error);
2526 switch (error)
2527 {
2528 case SSL_ERROR_SSL:
96f5fe4c
JH
2529 ERR_error_string(ERR_get_error(), ssl_errstring);
2530 log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring);
2531 return -1;
059ec3d9
PH
2532
2533 case SSL_ERROR_NONE:
96f5fe4c
JH
2534 left -= outbytes;
2535 buff += outbytes;
2536 break;
059ec3d9
PH
2537
2538 case SSL_ERROR_ZERO_RETURN:
96f5fe4c
JH
2539 log_write(0, LOG_MAIN, "SSL channel closed on write");
2540 return -1;
059ec3d9 2541
817d9f57 2542 case SSL_ERROR_SYSCALL:
96f5fe4c
JH
2543 log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s",
2544 sender_fullhost ? sender_fullhost : US"<unknown>",
2545 strerror(errno));
2546 return -1;
817d9f57 2547
059ec3d9 2548 default:
96f5fe4c
JH
2549 log_write(0, LOG_MAIN, "SSL_write error %d", error);
2550 return -1;
059ec3d9
PH
2551 }
2552 }
2553return len;
2554}
2555
2556
2557
2558/*************************************************
2559* Close down a TLS session *
2560*************************************************/
2561
2562/* This is also called from within a delivery subprocess forked from the
2563daemon, to shut down the TLS library, without actually doing a shutdown (which
2564would tamper with the SSL session in the parent process).
2565
2566Arguments: TRUE if SSL_shutdown is to be called
2567Returns: nothing
817d9f57
JH
2568
2569Used by both server-side and client-side TLS.
059ec3d9
PH
2570*/
2571
2572void
817d9f57 2573tls_close(BOOL is_server, BOOL shutdown)
059ec3d9 2574{
817d9f57 2575SSL **sslp = is_server ? &server_ssl : &client_ssl;
389ca47a 2576int *fdp = is_server ? &tls_in.active : &tls_out.active;
817d9f57
JH
2577
2578if (*fdp < 0) return; /* TLS was not active */
059ec3d9
PH
2579
2580if (shutdown)
2581 {
ec8b777a 2582 DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n");
817d9f57 2583 SSL_shutdown(*sslp);
059ec3d9
PH
2584 }
2585
817d9f57
JH
2586SSL_free(*sslp);
2587*sslp = NULL;
059ec3d9 2588
817d9f57 2589*fdp = -1;
059ec3d9
PH
2590}
2591
36f12725
NM
2592
2593
2594
2595/*************************************************
3375e053
PP
2596* Let tls_require_ciphers be checked at startup *
2597*************************************************/
2598
2599/* The tls_require_ciphers option, if set, must be something which the
2600library can parse.
2601
2602Returns: NULL on success, or error message
2603*/
2604
2605uschar *
2606tls_validate_require_cipher(void)
2607{
2608SSL_CTX *ctx;
2609uschar *s, *expciphers, *err;
2610
2611/* this duplicates from tls_init(), we need a better "init just global
2612state, for no specific purpose" singleton function of our own */
2613
2614SSL_load_error_strings();
2615OpenSSL_add_ssl_algorithms();
2616#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
2617/* SHA256 is becoming ever more popular. This makes sure it gets added to the
2618list of available digests. */
2619EVP_add_digest(EVP_sha256());
2620#endif
2621
2622if (!(tls_require_ciphers && *tls_require_ciphers))
2623 return NULL;
2624
cf0c6164
JH
2625if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers,
2626 &err))
3375e053
PP
2627 return US"failed to expand tls_require_ciphers";
2628
2629if (!(expciphers && *expciphers))
2630 return NULL;
2631
2632/* normalisation ripped from above */
2633s = expciphers;
2634while (*s != 0) { if (*s == '_') *s = '-'; s++; }
2635
2636err = NULL;
2637
2638ctx = SSL_CTX_new(SSLv23_server_method());
2639if (!ctx)
2640 {
2641 ERR_error_string(ERR_get_error(), ssl_errstring);
2642 return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring);
2643 }
2644
2645DEBUG(D_tls)
2646 debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);
2647
2648if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
2649 {
2650 ERR_error_string(ERR_get_error(), ssl_errstring);
cf0c6164
JH
2651 err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s",
2652 expciphers, ssl_errstring);
3375e053
PP
2653 }
2654
2655SSL_CTX_free(ctx);
2656
2657return err;
2658}
2659
2660
2661
2662
2663/*************************************************
36f12725
NM
2664* Report the library versions. *
2665*************************************************/
2666
2667/* There have historically been some issues with binary compatibility in
2668OpenSSL libraries; if Exim (like many other applications) is built against
2669one version of OpenSSL but the run-time linker picks up another version,
2670it can result in serious failures, including crashing with a SIGSEGV. So
2671report the version found by the compiler and the run-time version.
2672
f64a1e23
PP
2673Note: some OS vendors backport security fixes without changing the version
2674number/string, and the version date remains unchanged. The _build_ date
2675will change, so we can more usefully assist with version diagnosis by also
2676reporting the build date.
2677
36f12725
NM
2678Arguments: a FILE* to print the results to
2679Returns: nothing
2680*/
2681
2682void
2683tls_version_report(FILE *f)
2684{
754a0503 2685fprintf(f, "Library version: OpenSSL: Compile: %s\n"
f64a1e23
PP
2686 " Runtime: %s\n"
2687 " : %s\n",
754a0503 2688 OPENSSL_VERSION_TEXT,
f64a1e23
PP
2689 SSLeay_version(SSLEAY_VERSION),
2690 SSLeay_version(SSLEAY_BUILT_ON));
2691/* third line is 38 characters for the %s and the line is 73 chars long;
2692the OpenSSL output includes a "built on: " prefix already. */
36f12725
NM
2693}
2694
9e3331ea
TK
2695
2696
2697
2698/*************************************************
17c76198 2699* Random number generation *
9e3331ea
TK
2700*************************************************/
2701
2702/* Pseudo-random number generation. The result is not expected to be
2703cryptographically strong but not so weak that someone will shoot themselves
2704in the foot using it as a nonce in input in some email header scheme or
2705whatever weirdness they'll twist this into. The result should handle fork()
2706and avoid repeating sequences. OpenSSL handles that for us.
2707
2708Arguments:
2709 max range maximum
2710Returns a random number in range [0, max-1]
2711*/
2712
2713int
17c76198 2714vaguely_random_number(int max)
9e3331ea
TK
2715{
2716unsigned int r;
2717int i, needed_len;
de6135a0
PP
2718static pid_t pidlast = 0;
2719pid_t pidnow;
9e3331ea
TK
2720uschar *p;
2721uschar smallbuf[sizeof(r)];
2722
2723if (max <= 1)
2724 return 0;
2725
de6135a0
PP
2726pidnow = getpid();
2727if (pidnow != pidlast)
2728 {
2729 /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state
2730 is unique for each thread", this doesn't apparently apply across processes,
2731 so our own warning from vaguely_random_number_fallback() applies here too.
2732 Fix per PostgreSQL. */
2733 if (pidlast != 0)
2734 RAND_cleanup();
2735 pidlast = pidnow;
2736 }
2737
9e3331ea
TK
2738/* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */
2739if (!RAND_status())
2740 {
2741 randstuff r;
2742 gettimeofday(&r.tv, NULL);
2743 r.p = getpid();
2744
2745 RAND_seed((uschar *)(&r), sizeof(r));
2746 }
2747/* We're after pseudo-random, not random; if we still don't have enough data
2748in the internal PRNG then our options are limited. We could sleep and hope
2749for entropy to come along (prayer technique) but if the system is so depleted
2750in the first place then something is likely to just keep taking it. Instead,
2751we'll just take whatever little bit of pseudo-random we can still manage to
2752get. */
2753
2754needed_len = sizeof(r);
2755/* Don't take 8 times more entropy than needed if int is 8 octets and we were
2756asked for a number less than 10. */
2757for (r = max, i = 0; r; ++i)
2758 r >>= 1;
2759i = (i + 7) / 8;
2760if (i < needed_len)
2761 needed_len = i;
2762
c8dfb21d 2763#ifdef EXIM_HAVE_RAND_PSEUDO
9e3331ea 2764/* We do not care if crypto-strong */
17c76198 2765i = RAND_pseudo_bytes(smallbuf, needed_len);
c8dfb21d
JH
2766#else
2767i = RAND_bytes(smallbuf, needed_len);
2768#endif
2769
17c76198
PP
2770if (i < 0)
2771 {
2772 DEBUG(D_all)
2773 debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n");
2774 return vaguely_random_number_fallback(max);
2775 }
2776
9e3331ea
TK
2777r = 0;
2778for (p = smallbuf; needed_len; --needed_len, ++p)
2779 {
2780 r *= 256;
2781 r += *p;
2782 }
2783
2784/* We don't particularly care about weighted results; if someone wants
2785smooth distribution and cares enough then they should submit a patch then. */
2786return r % max;
2787}
2788
77bb000f
PP
2789
2790
2791
2792/*************************************************
2793* OpenSSL option parse *
2794*************************************************/
2795
2796/* Parse one option for tls_openssl_options_parse below
2797
2798Arguments:
2799 name one option name
2800 value place to store a value for it
2801Returns success or failure in parsing
2802*/
2803
2804struct exim_openssl_option {
2805 uschar *name;
2806 long value;
2807};
2808/* We could use a macro to expand, but we need the ifdef and not all the
2809options document which version they were introduced in. Policylet: include
2810all options unless explicitly for DTLS, let the administrator choose which
2811to apply.
2812
2813This list is current as of:
e2fbf4a2
PP
2814 ==> 1.0.1b <==
2815Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev
2816*/
77bb000f
PP
2817static struct exim_openssl_option exim_openssl_options[] = {
2818/* KEEP SORTED ALPHABETICALLY! */
2819#ifdef SSL_OP_ALL
73a46702 2820 { US"all", SSL_OP_ALL },
77bb000f
PP
2821#endif
2822#ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
73a46702 2823 { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION },
77bb000f
PP
2824#endif
2825#ifdef SSL_OP_CIPHER_SERVER_PREFERENCE
73a46702 2826 { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE },
77bb000f
PP
2827#endif
2828#ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
73a46702 2829 { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS },
77bb000f
PP
2830#endif
2831#ifdef SSL_OP_EPHEMERAL_RSA
73a46702 2832 { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA },
77bb000f
PP
2833#endif
2834#ifdef SSL_OP_LEGACY_SERVER_CONNECT
73a46702 2835 { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT },
77bb000f
PP
2836#endif
2837#ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
73a46702 2838 { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER },
77bb000f
PP
2839#endif
2840#ifdef SSL_OP_MICROSOFT_SESS_ID_BUG
73a46702 2841 { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG },
77bb000f
PP
2842#endif
2843#ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING
73a46702 2844 { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING },
77bb000f
PP
2845#endif
2846#ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG
73a46702 2847 { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG },
77bb000f
PP
2848#endif
2849#ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
73a46702 2850 { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG },
77bb000f 2851#endif
c80c5570
PP
2852#ifdef SSL_OP_NO_COMPRESSION
2853 { US"no_compression", SSL_OP_NO_COMPRESSION },
2854#endif
77bb000f 2855#ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
73a46702 2856 { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION },
77bb000f 2857#endif
c0c7b2da
PP
2858#ifdef SSL_OP_NO_SSLv2
2859 { US"no_sslv2", SSL_OP_NO_SSLv2 },
2860#endif
2861#ifdef SSL_OP_NO_SSLv3
2862 { US"no_sslv3", SSL_OP_NO_SSLv3 },
2863#endif
2864#ifdef SSL_OP_NO_TICKET
2865 { US"no_ticket", SSL_OP_NO_TICKET },
2866#endif
2867#ifdef SSL_OP_NO_TLSv1
2868 { US"no_tlsv1", SSL_OP_NO_TLSv1 },
2869#endif
c80c5570
PP
2870#ifdef SSL_OP_NO_TLSv1_1
2871#if SSL_OP_NO_TLSv1_1 == 0x00000400L
2872 /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */
2873#warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring
2874#else
2875 { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 },
2876#endif
2877#endif
2878#ifdef SSL_OP_NO_TLSv1_2
2879 { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 },
2880#endif
e2fbf4a2
PP
2881#ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG
2882 { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG },
2883#endif
77bb000f 2884#ifdef SSL_OP_SINGLE_DH_USE
73a46702 2885 { US"single_dh_use", SSL_OP_SINGLE_DH_USE },
77bb000f
PP
2886#endif
2887#ifdef SSL_OP_SINGLE_ECDH_USE
73a46702 2888 { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE },
77bb000f
PP
2889#endif
2890#ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG
73a46702 2891 { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG },
77bb000f
PP
2892#endif
2893#ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
73a46702 2894 { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG },
77bb000f
PP
2895#endif
2896#ifdef SSL_OP_TLS_BLOCK_PADDING_BUG
73a46702 2897 { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG },
77bb000f
PP
2898#endif
2899#ifdef SSL_OP_TLS_D5_BUG
73a46702 2900 { US"tls_d5_bug", SSL_OP_TLS_D5_BUG },
77bb000f
PP
2901#endif
2902#ifdef SSL_OP_TLS_ROLLBACK_BUG
73a46702 2903 { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG },
77bb000f
PP
2904#endif
2905};
2906static int exim_openssl_options_size =
2907 sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option);
2908
c80c5570 2909
77bb000f
PP
2910static BOOL
2911tls_openssl_one_option_parse(uschar *name, long *value)
2912{
2913int first = 0;
2914int last = exim_openssl_options_size;
2915while (last > first)
2916 {
2917 int middle = (first + last)/2;
2918 int c = Ustrcmp(name, exim_openssl_options[middle].name);
2919 if (c == 0)
2920 {
2921 *value = exim_openssl_options[middle].value;
2922 return TRUE;
2923 }
2924 else if (c > 0)
2925 first = middle + 1;
2926 else
2927 last = middle;
2928 }
2929return FALSE;
2930}
2931
2932
2933
2934
2935/*************************************************
2936* OpenSSL option parsing logic *
2937*************************************************/
2938
2939/* OpenSSL has a number of compatibility options which an administrator might
2940reasonably wish to set. Interpret a list similarly to decode_bits(), so that
2941we look like log_selector.
2942
2943Arguments:
2944 option_spec the administrator-supplied string of options
2945 results ptr to long storage for the options bitmap
2946Returns success or failure
2947*/
2948
2949BOOL
2950tls_openssl_options_parse(uschar *option_spec, long *results)
2951{
2952long result, item;
2953uschar *s, *end;
2954uschar keep_c;
2955BOOL adding, item_parsed;
2956
7006ee24 2957result = SSL_OP_NO_TICKET;
b1770b6e 2958/* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
da3ad30d 2959 * from default because it increases BEAST susceptibility. */
f0f5a555
PP
2960#ifdef SSL_OP_NO_SSLv2
2961result |= SSL_OP_NO_SSLv2;
2962#endif
a57b6200
JH
2963#ifdef SSL_OP_SINGLE_DH_USE
2964result |= SSL_OP_SINGLE_DH_USE;
2965#endif
77bb000f 2966
7006ee24 2967if (!option_spec)
77bb000f
PP
2968 {
2969 *results = result;
2970 return TRUE;
2971 }
2972
2973for (s=option_spec; *s != '\0'; /**/)
2974 {
2975 while (isspace(*s)) ++s;
2976 if (*s == '\0')
2977 break;
2978 if (*s != '+' && *s != '-')
2979 {
2980 DEBUG(D_tls) debug_printf("malformed openssl option setting: "
0e944a0d 2981 "+ or - expected but found \"%s\"\n", s);
77bb000f
PP
2982 return FALSE;
2983 }
2984 adding = *s++ == '+';
2985 for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ;
2986 keep_c = *end;
2987 *end = '\0';
2988 item_parsed = tls_openssl_one_option_parse(s, &item);
96f5fe4c 2989 *end = keep_c;
77bb000f
PP
2990 if (!item_parsed)
2991 {
0e944a0d 2992 DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s);
77bb000f
PP
2993 return FALSE;
2994 }
2995 DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n",
2996 adding ? "adding" : "removing", result, item, s);
2997 if (adding)
2998 result |= item;
2999 else
3000 result &= ~item;
77bb000f
PP
3001 s = end;
3002 }
3003
3004*results = result;
3005return TRUE;
3006}
3007
9d1c15ef
JH
3008/* vi: aw ai sw=2
3009*/
059ec3d9 3010/* End of tls-openssl.c */