Commit | Line | Data |
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059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
3386088d | 5 | /* Copyright (c) University of Cambridge 1995 - 2015 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
f5d78688 JH |
8 | /* Portions Copyright (c) The OpenSSL Project 1999 */ |
9 | ||
059ec3d9 PH |
10 | /* This module provides the TLS (aka SSL) support for Exim using the OpenSSL |
11 | library. It is #included into the tls.c file when that library is used. The | |
12 | code herein is based on a patch that was originally contributed by Steve | |
13 | Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara. | |
14 | ||
15 | No cryptographic code is included in Exim. All this module does is to call | |
16 | functions from the OpenSSL library. */ | |
17 | ||
18 | ||
19 | /* Heading stuff */ | |
20 | ||
21 | #include <openssl/lhash.h> | |
22 | #include <openssl/ssl.h> | |
23 | #include <openssl/err.h> | |
24 | #include <openssl/rand.h> | |
10ca4f1c JH |
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 JH |
31 | #ifdef EXPERIMENTAL_DANE |
32 | # include <danessl.h> | |
33 | #endif | |
34 | ||
3f7eeb86 | 35 | |
f2de3a33 JH |
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 |
34e3241d PP |
44 | |
45 | /* | |
46 | * X509_check_host provides sane certificate hostname checking, but was added | |
47 | * to OpenSSL late, after other projects forked off the code-base. So in | |
48 | * addition to guarding against the base version number, beware that LibreSSL | |
49 | * does not (at this time) support this function. | |
50 | * | |
51 | * If LibreSSL gains a different API, perhaps via libtls, then we'll probably | |
52 | * opt to disentangle and ask a LibreSSL user to provide glue for a third | |
53 | * crypto provider for libtls instead of continuing to tie the OpenSSL glue | |
54 | * into even twistier knots. If LibreSSL gains the same API, we can just | |
55 | * change this guard and punt the issue for a while longer. | |
56 | */ | |
57 | #ifndef LIBRESSL_VERSION_NUMBER | |
58 | # if OPENSSL_VERSION_NUMBER >= 0x010100000L | |
59 | # define EXIM_HAVE_OPENSSL_CHECKHOST | |
60 | # endif | |
61 | # if OPENSSL_VERSION_NUMBER >= 0x010000000L \ | |
2dfb468b | 62 | && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L |
34e3241d PP |
63 | # define EXIM_HAVE_OPENSSL_CHECKHOST |
64 | # endif | |
10ca4f1c JH |
65 | |
66 | # if !defined(OPENSSL_NO_ECDH) | |
67 | # if OPENSSL_VERSION_NUMBER >= 0x0090800fL | |
68 | # define EXIM_HAVE_ECDH | |
69 | # endif | |
70 | # if OPENSSL_VERSION_NUMBER >= 0x10002000L | |
71 | # define EXIM_HAVE_OPENSSL_ECDH_AUTO | |
72 | # define EXIM_HAVE_OPENSSL_EC_NIST2NID | |
73 | # endif | |
74 | # endif | |
2dfb468b | 75 | #endif |
3bcbbbe2 | 76 | |
67791ce4 JH |
77 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
78 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
79 | # define DISABLE_OCSP | |
80 | #endif | |
81 | ||
059ec3d9 PH |
82 | /* Structure for collecting random data for seeding. */ |
83 | ||
84 | typedef struct randstuff { | |
9e3331ea TK |
85 | struct timeval tv; |
86 | pid_t p; | |
059ec3d9 PH |
87 | } randstuff; |
88 | ||
89 | /* Local static variables */ | |
90 | ||
a2ff477a JH |
91 | static BOOL client_verify_callback_called = FALSE; |
92 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
93 | static const uschar *sid_ctx = US"exim"; |
94 | ||
d4f09789 PP |
95 | /* We have three different contexts to care about. |
96 | ||
97 | Simple case: client, `client_ctx` | |
98 | As a client, we can be doing a callout or cut-through delivery while receiving | |
99 | a message. So we have a client context, which should have options initialised | |
100 | from the SMTP Transport. | |
101 | ||
102 | Server: | |
103 | There are two cases: with and without ServerNameIndication from the client. | |
104 | Given TLS SNI, we can be using different keys, certs and various other | |
105 | configuration settings, because they're re-expanded with $tls_sni set. This | |
106 | allows vhosting with TLS. This SNI is sent in the handshake. | |
107 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
108 | So as a server, we start out using `server_ctx`. | |
109 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
110 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
111 | configuration. | |
112 | */ | |
113 | ||
817d9f57 JH |
114 | static SSL_CTX *client_ctx = NULL; |
115 | static SSL_CTX *server_ctx = NULL; | |
116 | static SSL *client_ssl = NULL; | |
117 | static SSL *server_ssl = NULL; | |
389ca47a | 118 | |
35731706 | 119 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 120 | static SSL_CTX *server_sni = NULL; |
35731706 | 121 | #endif |
059ec3d9 PH |
122 | |
123 | static char ssl_errstring[256]; | |
124 | ||
125 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
126 | static BOOL client_verify_optional = FALSE; |
127 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 128 | |
f5d78688 | 129 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
130 | |
131 | ||
7be682ca PP |
132 | typedef struct tls_ext_ctx_cb { |
133 | uschar *certificate; | |
134 | uschar *privatekey; | |
f2de3a33 | 135 | #ifndef DISABLE_OCSP |
f5d78688 JH |
136 | BOOL is_server; |
137 | union { | |
138 | struct { | |
139 | uschar *file; | |
140 | uschar *file_expanded; | |
141 | OCSP_RESPONSE *response; | |
142 | } server; | |
143 | struct { | |
44662487 JH |
144 | X509_STORE *verify_store; /* non-null if status requested */ |
145 | BOOL verify_required; | |
f5d78688 JH |
146 | } client; |
147 | } u_ocsp; | |
3f7eeb86 | 148 | #endif |
7be682ca PP |
149 | uschar *dhparam; |
150 | /* these are cached from first expand */ | |
151 | uschar *server_cipher_list; | |
152 | /* only passed down to tls_error: */ | |
153 | host_item *host; | |
55414b25 | 154 | const uschar * verify_cert_hostnames; |
0cbf2b82 | 155 | #ifndef DISABLE_EVENT |
a7538db1 JH |
156 | uschar * event_action; |
157 | #endif | |
7be682ca PP |
158 | } tls_ext_ctx_cb; |
159 | ||
160 | /* should figure out a cleanup of API to handle state preserved per | |
161 | implementation, for various reasons, which can be void * in the APIs. | |
162 | For now, we hack around it. */ | |
817d9f57 JH |
163 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
164 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
165 | |
166 | static int | |
983207c1 JH |
167 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
168 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ); | |
059ec3d9 | 169 | |
3f7eeb86 | 170 | /* Callbacks */ |
3bcbbbe2 | 171 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 172 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 173 | #endif |
f2de3a33 | 174 | #ifndef DISABLE_OCSP |
f5d78688 | 175 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
176 | #endif |
177 | ||
059ec3d9 PH |
178 | |
179 | /************************************************* | |
180 | * Handle TLS error * | |
181 | *************************************************/ | |
182 | ||
183 | /* Called from lots of places when errors occur before actually starting to do | |
184 | the TLS handshake, that is, while the session is still in clear. Always returns | |
185 | DEFER for a server and FAIL for a client so that most calls can use "return | |
186 | tls_error(...)" to do this processing and then give an appropriate return. A | |
187 | single function is used for both server and client, because it is called from | |
188 | some shared functions. | |
189 | ||
190 | Argument: | |
191 | prefix text to include in the logged error | |
192 | host NULL if setting up a server; | |
193 | the connected host if setting up a client | |
7199e1ee | 194 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
195 | |
196 | Returns: OK/DEFER/FAIL | |
197 | */ | |
198 | ||
199 | static int | |
b8b1b5cb | 200 | tls_error(uschar * prefix, const host_item * host, uschar * msg) |
059ec3d9 | 201 | { |
c562fd30 | 202 | if (!msg) |
7199e1ee TF |
203 | { |
204 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 205 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
206 | } |
207 | ||
c562fd30 JH |
208 | if (host) |
209 | { | |
210 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s): %s", | |
211 | host->name, host->address, prefix, msg); | |
212 | return FAIL; | |
213 | } | |
214 | else | |
059ec3d9 | 215 | { |
7199e1ee | 216 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 217 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee | 218 | conn_info += 5; |
c562fd30 | 219 | /* I'd like to get separated H= here, but too hard for now */ |
7199e1ee TF |
220 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", |
221 | conn_info, prefix, msg); | |
059ec3d9 PH |
222 | return DEFER; |
223 | } | |
059ec3d9 PH |
224 | } |
225 | ||
226 | ||
227 | ||
228 | /************************************************* | |
229 | * Callback to generate RSA key * | |
230 | *************************************************/ | |
231 | ||
232 | /* | |
233 | Arguments: | |
234 | s SSL connection | |
235 | export not used | |
236 | keylength keylength | |
237 | ||
238 | Returns: pointer to generated key | |
239 | */ | |
240 | ||
241 | static RSA * | |
242 | rsa_callback(SSL *s, int export, int keylength) | |
243 | { | |
244 | RSA *rsa_key; | |
245 | export = export; /* Shut picky compilers up */ | |
246 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
247 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
248 | if (rsa_key == NULL) | |
249 | { | |
250 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
251 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
252 | ssl_errstring); | |
253 | return NULL; | |
254 | } | |
255 | return rsa_key; | |
256 | } | |
257 | ||
258 | ||
259 | ||
f5d78688 | 260 | /* Extreme debug |
f2de3a33 | 261 | #ifndef DISABLE_OCSP |
f5d78688 JH |
262 | void |
263 | x509_store_dump_cert_s_names(X509_STORE * store) | |
264 | { | |
265 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
266 | int i; | |
267 | static uschar name[256]; | |
268 | ||
269 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
270 | { | |
271 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
272 | if(tmp_obj->type == X509_LU_X509) | |
273 | { | |
274 | X509 * current_cert= tmp_obj->data.x509; | |
275 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
f69979cf | 276 | name[sizeof(name)-1] = '\0'; |
f5d78688 JH |
277 | debug_printf(" %s\n", name); |
278 | } | |
279 | } | |
280 | } | |
281 | #endif | |
282 | */ | |
283 | ||
059ec3d9 | 284 | |
0cbf2b82 | 285 | #ifndef DISABLE_EVENT |
f69979cf JH |
286 | static int |
287 | verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn, | |
288 | BOOL *calledp, const BOOL *optionalp, const uschar * what) | |
289 | { | |
290 | uschar * ev; | |
291 | uschar * yield; | |
292 | X509 * old_cert; | |
293 | ||
294 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; | |
295 | if (ev) | |
296 | { | |
297 | old_cert = tlsp->peercert; | |
298 | tlsp->peercert = X509_dup(cert); | |
299 | /* NB we do not bother setting peerdn */ | |
300 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) | |
301 | { | |
302 | log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: " | |
303 | "depth=%d cert=%s: %s", | |
304 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
305 | what, depth, dn, yield); | |
306 | *calledp = TRUE; | |
307 | if (!*optionalp) | |
308 | { | |
309 | if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */ | |
310 | return 1; /* reject (leaving peercert set) */ | |
311 | } | |
312 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
313 | "(host in tls_try_verify_hosts)\n"); | |
314 | } | |
315 | X509_free(tlsp->peercert); | |
316 | tlsp->peercert = old_cert; | |
317 | } | |
318 | return 0; | |
319 | } | |
320 | #endif | |
321 | ||
059ec3d9 PH |
322 | /************************************************* |
323 | * Callback for verification * | |
324 | *************************************************/ | |
325 | ||
326 | /* The SSL library does certificate verification if set up to do so. This | |
327 | callback has the current yes/no state is in "state". If verification succeeded, | |
f69979cf JH |
328 | we set the certificate-verified flag. If verification failed, what happens |
329 | depends on whether the client is required to present a verifiable certificate | |
330 | or not. | |
059ec3d9 PH |
331 | |
332 | If verification is optional, we change the state to yes, but still log the | |
333 | verification error. For some reason (it really would help to have proper | |
334 | documentation of OpenSSL), this callback function then gets called again, this | |
f69979cf JH |
335 | time with state = 1. We must take care not to set the private verified flag on |
336 | the second time through. | |
059ec3d9 PH |
337 | |
338 | Note: this function is not called if the client fails to present a certificate | |
339 | when asked. We get here only if a certificate has been received. Handling of | |
340 | optional verification for this case is done when requesting SSL to verify, by | |
341 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
342 | ||
a7538db1 JH |
343 | May be called multiple times for different issues with a certificate, even |
344 | for a given "depth" in the certificate chain. | |
345 | ||
059ec3d9 PH |
346 | Arguments: |
347 | state current yes/no state as 1/0 | |
348 | x509ctx certificate information. | |
a2ff477a | 349 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
350 | |
351 | Returns: 1 if verified, 0 if not | |
352 | */ | |
353 | ||
354 | static int | |
421aff85 JH |
355 | verify_callback(int state, X509_STORE_CTX *x509ctx, |
356 | tls_support *tlsp, BOOL *calledp, BOOL *optionalp) | |
059ec3d9 | 357 | { |
421aff85 | 358 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 359 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 360 | uschar dn[256]; |
059ec3d9 | 361 | |
f69979cf JH |
362 | X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn)); |
363 | dn[sizeof(dn)-1] = '\0'; | |
059ec3d9 PH |
364 | |
365 | if (state == 0) | |
366 | { | |
4c01d6ab JH |
367 | log_write(0, LOG_MAIN, "[%s] SSL verify error: depth=%d error=%s cert=%s", |
368 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
a7538db1 | 369 | depth, |
421aff85 | 370 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), |
f69979cf | 371 | dn); |
a2ff477a | 372 | *calledp = TRUE; |
9d1c15ef JH |
373 | if (!*optionalp) |
374 | { | |
f69979cf JH |
375 | if (!tlsp->peercert) |
376 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
377 | return 0; /* reject */ | |
9d1c15ef | 378 | } |
059ec3d9 PH |
379 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
380 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
381 | } |
382 | ||
a7538db1 | 383 | else if (depth != 0) |
059ec3d9 | 384 | { |
f69979cf | 385 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn); |
f2de3a33 | 386 | #ifndef DISABLE_OCSP |
f5d78688 JH |
387 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
388 | { /* client, wanting stapling */ | |
389 | /* Add the server cert's signing chain as the one | |
390 | for the verification of the OCSP stapled information. */ | |
94431adb | 391 | |
f5d78688 | 392 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, |
421aff85 | 393 | cert)) |
f5d78688 JH |
394 | ERR_clear_error(); |
395 | } | |
a7538db1 | 396 | #endif |
0cbf2b82 | 397 | #ifndef DISABLE_EVENT |
f69979cf JH |
398 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
399 | return 0; /* reject, with peercert set */ | |
f5d78688 | 400 | #endif |
059ec3d9 PH |
401 | } |
402 | else | |
403 | { | |
55414b25 | 404 | const uschar * verify_cert_hostnames; |
e51c7be2 | 405 | |
e51c7be2 JH |
406 | if ( tlsp == &tls_out |
407 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
408 | /* client, wanting hostname check */ | |
e51c7be2 | 409 | { |
f69979cf | 410 | |
740f36d4 | 411 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
f69979cf JH |
412 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
413 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
414 | # endif | |
415 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
416 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
417 | # endif | |
e51c7be2 | 418 | int sep = 0; |
55414b25 | 419 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 420 | uschar * name; |
d8e7834a JH |
421 | int rc; |
422 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
423 | if ((rc = X509_check_host(cert, name, 0, | |
8d692470 | 424 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
740f36d4 JH |
425 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS, |
426 | NULL))) | |
d8e7834a JH |
427 | { |
428 | if (rc < 0) | |
429 | { | |
93a6fce2 | 430 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
4c01d6ab | 431 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
432 | name = NULL; |
433 | } | |
e51c7be2 | 434 | break; |
d8e7834a | 435 | } |
e51c7be2 | 436 | if (!name) |
f69979cf | 437 | #else |
e51c7be2 | 438 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) |
f69979cf | 439 | #endif |
e51c7be2 JH |
440 | { |
441 | log_write(0, LOG_MAIN, | |
93a6fce2 | 442 | "[%s] SSL verify error: certificate name mismatch: \"%s\"", |
4c01d6ab | 443 | tlsp == &tls_out ? deliver_host_address : sender_host_address, |
f69979cf | 444 | dn); |
a3ef7310 JH |
445 | *calledp = TRUE; |
446 | if (!*optionalp) | |
f69979cf JH |
447 | { |
448 | if (!tlsp->peercert) | |
449 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
450 | return 0; /* reject */ | |
451 | } | |
a3ef7310 JH |
452 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
453 | "tls_try_verify_hosts)\n"); | |
e51c7be2 | 454 | } |
f69979cf | 455 | } |
e51c7be2 | 456 | |
0cbf2b82 | 457 | #ifndef DISABLE_EVENT |
f69979cf JH |
458 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
459 | return 0; /* reject, with peercert set */ | |
e51c7be2 JH |
460 | #endif |
461 | ||
93dcb1c2 | 462 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
f69979cf | 463 | *calledp ? "" : " authenticated", dn); |
93dcb1c2 JH |
464 | if (!*calledp) tlsp->certificate_verified = TRUE; |
465 | *calledp = TRUE; | |
059ec3d9 PH |
466 | } |
467 | ||
a7538db1 | 468 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
469 | } |
470 | ||
a2ff477a JH |
471 | static int |
472 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
473 | { | |
f5d78688 | 474 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); |
a2ff477a JH |
475 | } |
476 | ||
477 | static int | |
478 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
479 | { | |
f5d78688 | 480 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); |
a2ff477a JH |
481 | } |
482 | ||
059ec3d9 | 483 | |
e5cccda9 | 484 | #ifdef EXPERIMENTAL_DANE |
53a7196b | 485 | |
e5cccda9 JH |
486 | /* This gets called *by* the dane library verify callback, which interposes |
487 | itself. | |
488 | */ | |
489 | static int | |
490 | verify_callback_client_dane(int state, X509_STORE_CTX * x509ctx) | |
491 | { | |
492 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
f69979cf | 493 | uschar dn[256]; |
0cbf2b82 | 494 | #ifndef DISABLE_EVENT |
83b27293 | 495 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 496 | BOOL dummy_called, optional = FALSE; |
83b27293 | 497 | #endif |
e5cccda9 | 498 | |
f69979cf JH |
499 | X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn)); |
500 | dn[sizeof(dn)-1] = '\0'; | |
e5cccda9 | 501 | |
f69979cf | 502 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", dn); |
e5cccda9 | 503 | |
0cbf2b82 | 504 | #ifndef DISABLE_EVENT |
f69979cf JH |
505 | if (verify_event(&tls_out, cert, depth, dn, |
506 | &dummy_called, &optional, US"DANE")) | |
507 | return 0; /* reject, with peercert set */ | |
83b27293 JH |
508 | #endif |
509 | ||
e5cccda9 | 510 | if (state == 1) |
53a7196b | 511 | tls_out.dane_verified = |
e5cccda9 JH |
512 | tls_out.certificate_verified = TRUE; |
513 | return 1; | |
514 | } | |
53a7196b JH |
515 | |
516 | #endif /*EXPERIMENTAL_DANE*/ | |
e5cccda9 | 517 | |
059ec3d9 PH |
518 | |
519 | /************************************************* | |
520 | * Information callback * | |
521 | *************************************************/ | |
522 | ||
523 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
524 | are doing. We copy the string to the debugging output when TLS debugging has |
525 | been requested. | |
059ec3d9 PH |
526 | |
527 | Arguments: | |
528 | s the SSL connection | |
529 | where | |
530 | ret | |
531 | ||
532 | Returns: nothing | |
533 | */ | |
534 | ||
535 | static void | |
536 | info_callback(SSL *s, int where, int ret) | |
537 | { | |
538 | where = where; | |
539 | ret = ret; | |
540 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
541 | } | |
542 | ||
543 | ||
544 | ||
545 | /************************************************* | |
546 | * Initialize for DH * | |
547 | *************************************************/ | |
548 | ||
549 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
550 | ||
551 | Arguments: | |
038597d2 | 552 | sctx The current SSL CTX (inbound or outbound) |
a799883d | 553 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 554 | host connected host, if client; NULL if server |
059ec3d9 PH |
555 | |
556 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
557 | */ | |
558 | ||
559 | static BOOL | |
b8b1b5cb | 560 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host) |
059ec3d9 | 561 | { |
059ec3d9 PH |
562 | BIO *bio; |
563 | DH *dh; | |
564 | uschar *dhexpanded; | |
a799883d | 565 | const char *pem; |
059ec3d9 PH |
566 | |
567 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
568 | return FALSE; | |
569 | ||
0df4ab80 | 570 | if (!dhexpanded || !*dhexpanded) |
a799883d | 571 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 572 | else if (dhexpanded[0] == '/') |
059ec3d9 | 573 | { |
0df4ab80 | 574 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 575 | { |
7199e1ee | 576 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
577 | host, US strerror(errno)); |
578 | return FALSE; | |
059ec3d9 | 579 | } |
a799883d PP |
580 | } |
581 | else | |
582 | { | |
583 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 584 | { |
a799883d PP |
585 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
586 | return TRUE; | |
059ec3d9 | 587 | } |
a799883d | 588 | |
0df4ab80 | 589 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
590 | { |
591 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
592 | host, US strerror(errno)); | |
593 | return FALSE; | |
594 | } | |
595 | bio = BIO_new_mem_buf(CS pem, -1); | |
596 | } | |
597 | ||
0df4ab80 | 598 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 599 | { |
059ec3d9 | 600 | BIO_free(bio); |
a799883d PP |
601 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
602 | host, NULL); | |
603 | return FALSE; | |
604 | } | |
605 | ||
606 | /* Even if it is larger, we silently return success rather than cause things | |
607 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
608 | * debatable choice. */ | |
609 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
610 | { | |
611 | DEBUG(D_tls) | |
612 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
613 | 8*DH_size(dh), tls_dh_max_bits); | |
614 | } | |
615 | else | |
616 | { | |
617 | SSL_CTX_set_tmp_dh(sctx, dh); | |
618 | DEBUG(D_tls) | |
619 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
620 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
621 | } |
622 | ||
a799883d PP |
623 | DH_free(dh); |
624 | BIO_free(bio); | |
625 | ||
626 | return TRUE; | |
059ec3d9 PH |
627 | } |
628 | ||
629 | ||
630 | ||
631 | ||
038597d2 PP |
632 | /************************************************* |
633 | * Initialize for ECDH * | |
634 | *************************************************/ | |
635 | ||
636 | /* Load parameters for ECDH encryption. | |
637 | ||
638 | For now, we stick to NIST P-256 because: it's simple and easy to configure; | |
639 | it avoids any patent issues that might bite redistributors; despite events in | |
640 | the news and concerns over curve choices, we're not cryptographers, we're not | |
641 | pretending to be, and this is "good enough" to be better than no support, | |
642 | protecting against most adversaries. Given another year or two, there might | |
643 | be sufficient clarity about a "right" way forward to let us make an informed | |
644 | decision, instead of a knee-jerk reaction. | |
645 | ||
646 | Longer-term, we should look at supporting both various named curves and | |
647 | external files generated with "openssl ecparam", much as we do for init_dh(). | |
648 | We should also support "none" as a value, to explicitly avoid initialisation. | |
649 | ||
650 | Patches welcome. | |
651 | ||
652 | Arguments: | |
653 | sctx The current SSL CTX (inbound or outbound) | |
654 | host connected host, if client; NULL if server | |
655 | ||
656 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
657 | */ | |
658 | ||
659 | static BOOL | |
10ca4f1c | 660 | init_ecdh(SSL_CTX * sctx, host_item * host) |
038597d2 | 661 | { |
63f0dbe0 JH |
662 | #ifdef OPENSSL_NO_ECDH |
663 | return TRUE; | |
664 | #else | |
665 | ||
10ca4f1c JH |
666 | EC_KEY * ecdh; |
667 | uschar * exp_curve; | |
668 | int nid; | |
669 | BOOL rv; | |
670 | ||
038597d2 PP |
671 | if (host) /* No ECDH setup for clients, only for servers */ |
672 | return TRUE; | |
673 | ||
10ca4f1c | 674 | # ifndef EXIM_HAVE_ECDH |
038597d2 PP |
675 | DEBUG(D_tls) |
676 | debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); | |
677 | return TRUE; | |
038597d2 | 678 | # else |
10ca4f1c JH |
679 | |
680 | if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve)) | |
681 | return FALSE; | |
682 | if (!exp_curve || !*exp_curve) | |
683 | return TRUE; | |
684 | ||
685 | # ifdef EXIM_HAVE_OPENSSL_ECDH_AUTO | |
686 | /* check if new enough library to support auto ECDH temp key parameter selection */ | |
687 | if (Ustrcmp(exp_curve, "auto") == 0) | |
038597d2 | 688 | { |
10ca4f1c JH |
689 | DEBUG(D_tls) debug_printf( |
690 | "ECDH temp key parameter settings: OpenSSL 1.2+ autoselection\n"); | |
691 | SSL_CTX_set_ecdh_auto(sctx, 1); | |
692 | return TRUE; | |
693 | } | |
694 | # endif | |
038597d2 | 695 | |
10ca4f1c JH |
696 | DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve); |
697 | if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef | |
698 | # ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID | |
699 | && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef | |
700 | # endif | |
701 | ) | |
702 | { | |
703 | tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", | |
704 | exp_curve), | |
705 | host, NULL); | |
706 | return FALSE; | |
707 | } | |
038597d2 | 708 | |
10ca4f1c JH |
709 | if (!(ecdh = EC_KEY_new_by_curve_name(nid))) |
710 | { | |
aa7751be | 711 | tls_error(US"Unable to create ec curve", host, NULL); |
10ca4f1c | 712 | return FALSE; |
038597d2 | 713 | } |
10ca4f1c JH |
714 | |
715 | /* The "tmp" in the name here refers to setting a temporary key | |
716 | not to the stability of the interface. */ | |
717 | ||
718 | if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) | |
719 | tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL); | |
720 | else | |
721 | DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); | |
722 | ||
723 | EC_KEY_free(ecdh); | |
724 | return !rv; | |
725 | ||
726 | # endif /*EXIM_HAVE_ECDH*/ | |
727 | #endif /*OPENSSL_NO_ECDH*/ | |
038597d2 PP |
728 | } |
729 | ||
730 | ||
731 | ||
732 | ||
f2de3a33 | 733 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
734 | /************************************************* |
735 | * Load OCSP information into state * | |
736 | *************************************************/ | |
737 | ||
f5d78688 | 738 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
739 | caller has determined this is needed. Checks validity. Debugs a message |
740 | if invalid. | |
741 | ||
742 | ASSUMES: single response, for single cert. | |
743 | ||
744 | Arguments: | |
745 | sctx the SSL_CTX* to update | |
746 | cbinfo various parts of session state | |
747 | expanded the filename putatively holding an OCSP response | |
748 | ||
749 | */ | |
750 | ||
751 | static void | |
f5d78688 | 752 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 PP |
753 | { |
754 | BIO *bio; | |
755 | OCSP_RESPONSE *resp; | |
756 | OCSP_BASICRESP *basic_response; | |
757 | OCSP_SINGLERESP *single_response; | |
758 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
759 | X509_STORE *store; | |
760 | unsigned long verify_flags; | |
761 | int status, reason, i; | |
762 | ||
f5d78688 JH |
763 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
764 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 765 | { |
f5d78688 JH |
766 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
767 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
768 | } |
769 | ||
f5d78688 | 770 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); |
3f7eeb86 PP |
771 | if (!bio) |
772 | { | |
773 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 774 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
775 | return; |
776 | } | |
777 | ||
778 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
779 | BIO_free(bio); | |
780 | if (!resp) | |
781 | { | |
782 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
783 | return; | |
784 | } | |
785 | ||
786 | status = OCSP_response_status(resp); | |
787 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
788 | { | |
789 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
790 | OCSP_response_status_str(status), status); | |
f5d78688 | 791 | goto bad; |
3f7eeb86 PP |
792 | } |
793 | ||
794 | basic_response = OCSP_response_get1_basic(resp); | |
795 | if (!basic_response) | |
796 | { | |
797 | DEBUG(D_tls) | |
798 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 799 | goto bad; |
3f7eeb86 PP |
800 | } |
801 | ||
802 | store = SSL_CTX_get_cert_store(sctx); | |
803 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
804 | ||
805 | /* May need to expose ability to adjust those flags? | |
806 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
807 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
808 | ||
809 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
810 | if (i <= 0) | |
811 | { | |
812 | DEBUG(D_tls) { | |
813 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
814 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
815 | } |
816 | goto bad; | |
3f7eeb86 PP |
817 | } |
818 | ||
819 | /* Here's the simplifying assumption: there's only one response, for the | |
820 | one certificate we use, and nothing for anything else in a chain. If this | |
821 | proves false, we need to extract a cert id from our issued cert | |
822 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
823 | right cert in the stack and then calls OCSP_single_get0_status()). | |
824 | ||
825 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
826 | single_response = OCSP_resp_get0(basic_response, 0); | |
827 | if (!single_response) | |
828 | { | |
829 | DEBUG(D_tls) | |
830 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 831 | goto bad; |
3f7eeb86 PP |
832 | } |
833 | ||
834 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 835 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 836 | { |
f5d78688 JH |
837 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
838 | OCSP_cert_status_str(status), status, | |
839 | OCSP_crl_reason_str(reason), reason); | |
840 | goto bad; | |
3f7eeb86 PP |
841 | } |
842 | ||
843 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
844 | { | |
845 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 846 | goto bad; |
3f7eeb86 PP |
847 | } |
848 | ||
f5d78688 | 849 | supply_response: |
018058b2 | 850 | cbinfo->u_ocsp.server.response = resp; |
f5d78688 JH |
851 | return; |
852 | ||
853 | bad: | |
018058b2 JH |
854 | if (running_in_test_harness) |
855 | { | |
856 | extern char ** environ; | |
857 | uschar ** p; | |
858 | for (p = USS environ; *p != NULL; p++) | |
859 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
860 | { | |
861 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
862 | goto supply_response; | |
863 | } | |
864 | } | |
f5d78688 | 865 | return; |
3f7eeb86 | 866 | } |
f2de3a33 | 867 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
868 | |
869 | ||
870 | ||
871 | ||
7be682ca PP |
872 | /************************************************* |
873 | * Expand key and cert file specs * | |
874 | *************************************************/ | |
875 | ||
f5d78688 | 876 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
877 | new context, if Server Name Indication was used and tls_sni was seen in |
878 | the certificate string. | |
879 | ||
880 | Arguments: | |
881 | sctx the SSL_CTX* to update | |
882 | cbinfo various parts of session state | |
883 | ||
884 | Returns: OK/DEFER/FAIL | |
885 | */ | |
886 | ||
887 | static int | |
3f7eeb86 | 888 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
889 | { |
890 | uschar *expanded; | |
891 | ||
892 | if (cbinfo->certificate == NULL) | |
893 | return OK; | |
894 | ||
d9b2312b JH |
895 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
896 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
897 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
898 | ) | |
7be682ca PP |
899 | reexpand_tls_files_for_sni = TRUE; |
900 | ||
901 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
902 | return DEFER; | |
903 | ||
904 | if (expanded != NULL) | |
905 | { | |
906 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
907 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
908 | return tls_error(string_sprintf( | |
909 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
910 | cbinfo->host, NULL); | |
911 | } | |
912 | ||
913 | if (cbinfo->privatekey != NULL && | |
914 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
915 | return DEFER; | |
916 | ||
917 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
918 | of the expansion is an empty string, ignore it also, and assume the private | |
919 | key is in the same file as the certificate. */ | |
920 | ||
921 | if (expanded != NULL && *expanded != 0) | |
922 | { | |
923 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
924 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
925 | return tls_error(string_sprintf( | |
926 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
927 | } | |
928 | ||
f2de3a33 | 929 | #ifndef DISABLE_OCSP |
f5d78688 | 930 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) |
3f7eeb86 | 931 | { |
f5d78688 | 932 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) |
3f7eeb86 PP |
933 | return DEFER; |
934 | ||
935 | if (expanded != NULL && *expanded != 0) | |
936 | { | |
937 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f5d78688 JH |
938 | if (cbinfo->u_ocsp.server.file_expanded && |
939 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 PP |
940 | { |
941 | DEBUG(D_tls) | |
942 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
943 | } else { | |
944 | ocsp_load_response(sctx, cbinfo, expanded); | |
945 | } | |
946 | } | |
947 | } | |
948 | #endif | |
949 | ||
7be682ca PP |
950 | return OK; |
951 | } | |
952 | ||
953 | ||
954 | ||
955 | ||
956 | /************************************************* | |
957 | * Callback to handle SNI * | |
958 | *************************************************/ | |
959 | ||
960 | /* Called when acting as server during the TLS session setup if a Server Name | |
961 | Indication extension was sent by the client. | |
962 | ||
963 | API documentation is OpenSSL s_server.c implementation. | |
964 | ||
965 | Arguments: | |
966 | s SSL* of the current session | |
967 | ad unknown (part of OpenSSL API) (unused) | |
968 | arg Callback of "our" registered data | |
969 | ||
970 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
971 | */ | |
972 | ||
3bcbbbe2 | 973 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
974 | static int |
975 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
976 | { | |
977 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 978 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 979 | int rc; |
3f0945ff | 980 | int old_pool = store_pool; |
7be682ca PP |
981 | |
982 | if (!servername) | |
983 | return SSL_TLSEXT_ERR_OK; | |
984 | ||
3f0945ff | 985 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
986 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
987 | ||
988 | /* Make the extension value available for expansion */ | |
3f0945ff | 989 | store_pool = POOL_PERM; |
817d9f57 | 990 | tls_in.sni = string_copy(US servername); |
3f0945ff | 991 | store_pool = old_pool; |
7be682ca PP |
992 | |
993 | if (!reexpand_tls_files_for_sni) | |
994 | return SSL_TLSEXT_ERR_OK; | |
995 | ||
996 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
997 | not confident that memcpy wouldn't break some internal reference counting. | |
998 | Especially since there's a references struct member, which would be off. */ | |
999 | ||
0df4ab80 | 1000 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7be682ca PP |
1001 | { |
1002 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1003 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
1004 | return SSL_TLSEXT_ERR_NOACK; | |
1005 | } | |
1006 | ||
1007 | /* Not sure how many of these are actually needed, since SSL object | |
1008 | already exists. Might even need this selfsame callback, for reneg? */ | |
1009 | ||
817d9f57 JH |
1010 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
1011 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
1012 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
1013 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
1014 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
1015 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
038597d2 PP |
1016 | |
1017 | if ( !init_dh(server_sni, cbinfo->dhparam, NULL) | |
1018 | || !init_ecdh(server_sni, NULL) | |
1019 | ) | |
1020 | return SSL_TLSEXT_ERR_NOACK; | |
1021 | ||
7be682ca | 1022 | if (cbinfo->server_cipher_list) |
817d9f57 | 1023 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
f2de3a33 | 1024 | #ifndef DISABLE_OCSP |
f5d78688 | 1025 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1026 | { |
f5d78688 | 1027 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 1028 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
1029 | } |
1030 | #endif | |
7be682ca | 1031 | |
983207c1 | 1032 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server); |
7be682ca PP |
1033 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
1034 | ||
3f7eeb86 PP |
1035 | /* do this after setup_certs, because this can require the certs for verifying |
1036 | OCSP information. */ | |
038597d2 | 1037 | if ((rc = tls_expand_session_files(server_sni, cbinfo)) != OK) |
0df4ab80 | 1038 | return SSL_TLSEXT_ERR_NOACK; |
a799883d | 1039 | |
7be682ca | 1040 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 1041 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
1042 | |
1043 | return SSL_TLSEXT_ERR_OK; | |
1044 | } | |
3bcbbbe2 | 1045 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
1046 | |
1047 | ||
1048 | ||
1049 | ||
f2de3a33 | 1050 | #ifndef DISABLE_OCSP |
f5d78688 | 1051 | |
3f7eeb86 PP |
1052 | /************************************************* |
1053 | * Callback to handle OCSP Stapling * | |
1054 | *************************************************/ | |
1055 | ||
1056 | /* Called when acting as server during the TLS session setup if the client | |
1057 | requests OCSP information with a Certificate Status Request. | |
1058 | ||
1059 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
1060 | project. | |
1061 | ||
1062 | */ | |
1063 | ||
1064 | static int | |
f5d78688 | 1065 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
1066 | { |
1067 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
1068 | uschar *response_der; | |
1069 | int response_der_len; | |
1070 | ||
af4a1bca | 1071 | DEBUG(D_tls) |
b3ef41c9 | 1072 | debug_printf("Received TLS status request (OCSP stapling); %s response\n", |
f5d78688 JH |
1073 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
1074 | ||
44662487 | 1075 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 1076 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
1077 | return SSL_TLSEXT_ERR_NOACK; |
1078 | ||
1079 | response_der = NULL; | |
44662487 JH |
1080 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, |
1081 | &response_der); | |
3f7eeb86 PP |
1082 | if (response_der_len <= 0) |
1083 | return SSL_TLSEXT_ERR_NOACK; | |
1084 | ||
5e55c7a9 | 1085 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 1086 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
1087 | return SSL_TLSEXT_ERR_OK; |
1088 | } | |
1089 | ||
3f7eeb86 | 1090 | |
f5d78688 JH |
1091 | static void |
1092 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
1093 | { | |
1094 | BIO_printf(bp, "\t%s: ", str); | |
1095 | ASN1_GENERALIZEDTIME_print(bp, time); | |
1096 | BIO_puts(bp, "\n"); | |
1097 | } | |
1098 | ||
1099 | static int | |
1100 | tls_client_stapling_cb(SSL *s, void *arg) | |
1101 | { | |
1102 | tls_ext_ctx_cb * cbinfo = arg; | |
1103 | const unsigned char * p; | |
1104 | int len; | |
1105 | OCSP_RESPONSE * rsp; | |
1106 | OCSP_BASICRESP * bs; | |
1107 | int i; | |
1108 | ||
1109 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
1110 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
1111 | if(!p) | |
1112 | { | |
44662487 | 1113 | /* Expect this when we requested ocsp but got none */ |
6c6d6e48 | 1114 | if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher)) |
44662487 | 1115 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); |
f5d78688 JH |
1116 | else |
1117 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1118 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1119 | } |
018058b2 | 1120 | |
f5d78688 JH |
1121 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
1122 | { | |
018058b2 | 1123 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1124 | if (LOGGING(tls_cipher)) |
1eca31ca | 1125 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
1126 | else |
1127 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1128 | return 0; | |
1129 | } | |
1130 | ||
1131 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
1132 | { | |
018058b2 | 1133 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1134 | if (LOGGING(tls_cipher)) |
1eca31ca | 1135 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1136 | else |
1137 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1138 | OCSP_RESPONSE_free(rsp); | |
1139 | return 0; | |
1140 | } | |
1141 | ||
1142 | /* We'd check the nonce here if we'd put one in the request. */ | |
1143 | /* However that would defeat cacheability on the server so we don't. */ | |
1144 | ||
f5d78688 JH |
1145 | /* This section of code reworked from OpenSSL apps source; |
1146 | The OpenSSL Project retains copyright: | |
1147 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1148 | */ | |
1149 | { | |
1150 | BIO * bp = NULL; | |
f5d78688 JH |
1151 | int status, reason; |
1152 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1153 | ||
1154 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
1155 | ||
1156 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1157 | ||
1158 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1159 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1160 | ||
44662487 JH |
1161 | if ((i = OCSP_basic_verify(bs, NULL, |
1162 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
f5d78688 | 1163 | { |
018058b2 | 1164 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1165 | if (LOGGING(tls_cipher)) |
1eca31ca | 1166 | log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable"); |
f5d78688 JH |
1167 | BIO_printf(bp, "OCSP response verify failure\n"); |
1168 | ERR_print_errors(bp); | |
44662487 | 1169 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 JH |
1170 | goto out; |
1171 | } | |
1172 | ||
1173 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1174 | ||
1175 | { | |
1176 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
1177 | OCSP_SINGLERESP * single; | |
1178 | ||
1179 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
1180 | { | |
018058b2 | 1181 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1182 | log_write(0, LOG_MAIN, "OCSP stapling " |
1183 | "with multiple responses not handled"); | |
1184 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
f5d78688 JH |
1185 | goto out; |
1186 | } | |
1187 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1188 | status = OCSP_single_get0_status(single, &reason, &rev, |
1189 | &thisupd, &nextupd); | |
f5d78688 JH |
1190 | } |
1191 | ||
f5d78688 JH |
1192 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1193 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1194 | if (!OCSP_check_validity(thisupd, nextupd, |
1195 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1196 | { |
018058b2 | 1197 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1198 | DEBUG(D_tls) ERR_print_errors(bp); |
1199 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
44662487 | 1200 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1201 | } |
44662487 | 1202 | else |
f5d78688 | 1203 | { |
44662487 JH |
1204 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1205 | OCSP_cert_status_str(status)); | |
1206 | switch(status) | |
1207 | { | |
1208 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1209 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1210 | i = 1; |
44662487 JH |
1211 | break; |
1212 | case V_OCSP_CERTSTATUS_REVOKED: | |
018058b2 | 1213 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1214 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1215 | reason != -1 ? "; reason: " : "", | |
1216 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1217 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
1218 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1219 | break; | |
1220 | default: | |
018058b2 | 1221 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1222 | log_write(0, LOG_MAIN, |
1223 | "Server certificate status unknown, in OCSP stapling"); | |
1224 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1225 | break; | |
1226 | } | |
f5d78688 JH |
1227 | } |
1228 | out: | |
1229 | BIO_free(bp); | |
1230 | } | |
1231 | ||
1232 | OCSP_RESPONSE_free(rsp); | |
1233 | return i; | |
1234 | } | |
f2de3a33 | 1235 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1236 | |
1237 | ||
059ec3d9 PH |
1238 | /************************************************* |
1239 | * Initialize for TLS * | |
1240 | *************************************************/ | |
1241 | ||
e51c7be2 JH |
1242 | /* Called from both server and client code, to do preliminary initialization |
1243 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1244 | |
1245 | Arguments: | |
946ecbe0 | 1246 | ctxp returned SSL context |
059ec3d9 PH |
1247 | host connected host, if client; NULL if server |
1248 | dhparam DH parameter file | |
1249 | certificate certificate file | |
1250 | privatekey private key | |
f5d78688 | 1251 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1252 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1253 | cbp place to put allocated callback context |
059ec3d9 PH |
1254 | |
1255 | Returns: OK/DEFER/FAIL | |
1256 | */ | |
1257 | ||
1258 | static int | |
817d9f57 | 1259 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1260 | uschar *privatekey, |
f2de3a33 | 1261 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1262 | uschar *ocsp_file, |
1263 | #endif | |
817d9f57 | 1264 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 1265 | { |
77bb000f | 1266 | long init_options; |
7be682ca | 1267 | int rc; |
77bb000f | 1268 | BOOL okay; |
a7538db1 | 1269 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1270 | |
1271 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1272 | cbinfo->certificate = certificate; | |
1273 | cbinfo->privatekey = privatekey; | |
f2de3a33 | 1274 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1275 | if ((cbinfo->is_server = host==NULL)) |
1276 | { | |
1277 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1278 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1279 | cbinfo->u_ocsp.server.response = NULL; | |
1280 | } | |
1281 | else | |
1282 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1283 | #endif |
7be682ca | 1284 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1285 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1286 | cbinfo->host = host; |
0cbf2b82 | 1287 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1288 | cbinfo->event_action = NULL; |
1289 | #endif | |
77bb000f | 1290 | |
059ec3d9 PH |
1291 | SSL_load_error_strings(); /* basic set up */ |
1292 | OpenSSL_add_ssl_algorithms(); | |
1293 | ||
388d6564 | 1294 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 1295 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1296 | list of available digests. */ |
1297 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1298 | #endif |
a0475b69 | 1299 | |
f0f5a555 PP |
1300 | /* Create a context. |
1301 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1302 | negotiation in the different methods; as far as I can tell, the only | |
1303 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1304 | when OpenSSL is built without SSLv2 support. | |
1305 | By disabling with openssl_options, we can let admins re-enable with the | |
1306 | existing knob. */ | |
059ec3d9 | 1307 | |
817d9f57 | 1308 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
1309 | SSLv23_server_method() : SSLv23_client_method()); |
1310 | ||
817d9f57 | 1311 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
1312 | |
1313 | /* It turns out that we need to seed the random number generator this early in | |
1314 | order to get the full complement of ciphers to work. It took me roughly a day | |
1315 | of work to discover this by experiment. | |
1316 | ||
1317 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1318 | there. Otherwise, we have to make something up as best we can. Double check | |
1319 | afterwards. */ | |
1320 | ||
1321 | if (!RAND_status()) | |
1322 | { | |
1323 | randstuff r; | |
9e3331ea | 1324 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1325 | r.p = getpid(); |
1326 | ||
1327 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1328 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1329 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1330 | ||
1331 | if (!RAND_status()) | |
7199e1ee | 1332 | return tls_error(US"RAND_status", host, |
5ca6d115 | 1333 | US"unable to seed random number generator"); |
059ec3d9 PH |
1334 | } |
1335 | ||
1336 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1337 | level. */ | |
1338 | ||
f69979cf | 1339 | DEBUG(D_tls) SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 1340 | |
c80c5570 | 1341 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 1342 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1343 | |
77bb000f PP |
1344 | /* Apply administrator-supplied work-arounds. |
1345 | Historically we applied just one requested option, | |
1346 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1347 | moved to an administrator-controlled list of options to specify and | |
1348 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1349 | |
77bb000f PP |
1350 | No OpenSSL version number checks: the options we accept depend upon the |
1351 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1352 | |
77bb000f PP |
1353 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
1354 | if (!okay) | |
73a46702 | 1355 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
1356 | |
1357 | if (init_options) | |
1358 | { | |
1359 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 1360 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
1361 | return tls_error(string_sprintf( |
1362 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1363 | } | |
1364 | else | |
1365 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
1366 | |
1367 | /* Initialize with DH parameters if supplied */ | |
10ca4f1c | 1368 | /* Initialize ECDH temp key parameter selection */ |
059ec3d9 | 1369 | |
038597d2 PP |
1370 | if ( !init_dh(*ctxp, dhparam, host) |
1371 | || !init_ecdh(*ctxp, host) | |
1372 | ) | |
1373 | return DEFER; | |
059ec3d9 | 1374 | |
3f7eeb86 | 1375 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1376 | |
817d9f57 | 1377 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 1378 | if (rc != OK) return rc; |
c91535f3 | 1379 | |
7be682ca | 1380 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 1381 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
f5d78688 | 1382 | if (host == NULL) /* server */ |
3f0945ff | 1383 | { |
f2de3a33 | 1384 | # ifndef DISABLE_OCSP |
f5d78688 | 1385 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1386 | the option exists, not what the current expansion might be, as SNI might |
1387 | change the certificate and OCSP file in use between now and the time the | |
1388 | callback is invoked. */ | |
f5d78688 | 1389 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1390 | { |
f5d78688 | 1391 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); |
5e55c7a9 | 1392 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); |
3f7eeb86 | 1393 | } |
f5d78688 | 1394 | # endif |
3f0945ff PP |
1395 | /* We always do this, so that $tls_sni is available even if not used in |
1396 | tls_certificate */ | |
817d9f57 JH |
1397 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
1398 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 1399 | } |
f2de3a33 | 1400 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1401 | else /* client */ |
1402 | if(ocsp_file) /* wanting stapling */ | |
1403 | { | |
1404 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1405 | { | |
1406 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1407 | return FAIL; | |
1408 | } | |
1409 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1410 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1411 | } | |
1412 | # endif | |
7be682ca | 1413 | #endif |
059ec3d9 | 1414 | |
e51c7be2 | 1415 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 1416 | |
059ec3d9 PH |
1417 | /* Set up the RSA callback */ |
1418 | ||
817d9f57 | 1419 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
1420 | |
1421 | /* Finally, set the timeout, and we are done */ | |
1422 | ||
817d9f57 | 1423 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 1424 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1425 | |
817d9f57 | 1426 | *cbp = cbinfo; |
7be682ca | 1427 | |
059ec3d9 PH |
1428 | return OK; |
1429 | } | |
1430 | ||
1431 | ||
1432 | ||
1433 | ||
1434 | /************************************************* | |
1435 | * Get name of cipher in use * | |
1436 | *************************************************/ | |
1437 | ||
817d9f57 | 1438 | /* |
059ec3d9 | 1439 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1440 | buffer to use for answer |
1441 | size of buffer | |
1442 | pointer to number of bits for cipher | |
059ec3d9 PH |
1443 | Returns: nothing |
1444 | */ | |
1445 | ||
1446 | static void | |
817d9f57 | 1447 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1448 | { |
57b3a7f5 PP |
1449 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1450 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1451 | the accessor functions use const in the prototype. */ | |
1452 | const SSL_CIPHER *c; | |
d9784128 | 1453 | const uschar *ver; |
059ec3d9 | 1454 | |
d9784128 | 1455 | ver = (const uschar *)SSL_get_version(ssl); |
059ec3d9 | 1456 | |
57b3a7f5 | 1457 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1458 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1459 | |
817d9f57 JH |
1460 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1461 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1462 | |
1463 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1464 | } | |
1465 | ||
1466 | ||
f69979cf JH |
1467 | static void |
1468 | peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned bsize) | |
1469 | { | |
1470 | /*XXX we might consider a list-of-certs variable for the cert chain. | |
1471 | SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support | |
1472 | in list-handling functions, also consider the difference between the entire | |
1473 | chain and the elements sent by the peer. */ | |
1474 | ||
1475 | /* Will have already noted peercert on a verify fail; possibly not the leaf */ | |
1476 | if (!tlsp->peercert) | |
1477 | tlsp->peercert = SSL_get_peer_certificate(ssl); | |
1478 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
1479 | if (tlsp->peercert) | |
1480 | { | |
1481 | X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, bsize); | |
1482 | peerdn[bsize-1] = '\0'; | |
1483 | tlsp->peerdn = peerdn; /*XXX a static buffer... */ | |
1484 | } | |
1485 | else | |
1486 | tlsp->peerdn = NULL; | |
1487 | } | |
1488 | ||
1489 | ||
059ec3d9 PH |
1490 | |
1491 | ||
1492 | ||
1493 | /************************************************* | |
1494 | * Set up for verifying certificates * | |
1495 | *************************************************/ | |
1496 | ||
1497 | /* Called by both client and server startup | |
1498 | ||
1499 | Arguments: | |
7be682ca | 1500 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1501 | certs certs file or NULL |
1502 | crl CRL file or NULL | |
1503 | host NULL in a server; the remote host in a client | |
1504 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1505 | otherwise passed as FALSE | |
983207c1 | 1506 | cert_vfy_cb Callback function for certificate verification |
059ec3d9 PH |
1507 | |
1508 | Returns: OK/DEFER/FAIL | |
1509 | */ | |
1510 | ||
1511 | static int | |
983207c1 JH |
1512 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
1513 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ) | |
059ec3d9 PH |
1514 | { |
1515 | uschar *expcerts, *expcrl; | |
1516 | ||
1517 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1518 | return DEFER; | |
1519 | ||
26e72755 | 1520 | if (expcerts != NULL && *expcerts != '\0') |
059ec3d9 | 1521 | { |
cb1d7830 | 1522 | if (Ustrcmp(expcerts, "system") == 0) |
059ec3d9 | 1523 | { |
cb1d7830 JH |
1524 | /* Tell the library to use its compiled-in location for the system default |
1525 | CA bundle, only */ | |
1526 | ||
1527 | if (!SSL_CTX_set_default_verify_paths(sctx)) | |
1528 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); | |
059ec3d9 PH |
1529 | } |
1530 | else | |
1531 | { | |
cb1d7830 JH |
1532 | struct stat statbuf; |
1533 | ||
1534 | /* Tell the library to use its compiled-in location for the system default | |
1535 | CA bundle. Those given by the exim config are additional to these */ | |
1536 | ||
1537 | if (!SSL_CTX_set_default_verify_paths(sctx)) | |
1538 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); | |
1539 | ||
1540 | if (Ustat(expcerts, &statbuf) < 0) | |
1541 | { | |
1542 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1543 | "failed to stat %s for certificates", expcerts); | |
1544 | return DEFER; | |
1545 | } | |
059ec3d9 | 1546 | else |
059ec3d9 | 1547 | { |
cb1d7830 JH |
1548 | uschar *file, *dir; |
1549 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1550 | { file = NULL; dir = expcerts; } | |
1551 | else | |
1552 | { file = expcerts; dir = NULL; } | |
1553 | ||
1554 | /* If a certificate file is empty, the next function fails with an | |
1555 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1556 | certificates are recognized, but the error message is still misleading (it | |
1557 | says no certificate was supplied.) But this is better. */ | |
1558 | ||
1559 | if ((file == NULL || statbuf.st_size > 0) && | |
1560 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
1561 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); | |
1562 | ||
1563 | /* Load the list of CAs for which we will accept certs, for sending | |
1564 | to the client. This is only for the one-file tls_verify_certificates | |
1565 | variant. | |
1566 | If a list isn't loaded into the server, but | |
1567 | some verify locations are set, the server end appears to make | |
1568 | a wildcard reqest for client certs. | |
1569 | Meanwhile, the client library as deafult behaviour *ignores* the list | |
1570 | we send over the wire - see man SSL_CTX_set_client_cert_cb. | |
1571 | Because of this, and that the dir variant is likely only used for | |
1572 | the public-CA bundle (not for a private CA), not worth fixing. | |
1573 | */ | |
1574 | if (file != NULL) | |
1575 | { | |
1576 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); | |
1577 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", | |
1578 | sk_X509_NAME_num(names)); | |
1579 | SSL_CTX_set_client_CA_list(sctx, names); | |
1580 | } | |
059ec3d9 PH |
1581 | } |
1582 | } | |
1583 | ||
1584 | /* Handle a certificate revocation list. */ | |
1585 | ||
1586 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1587 | ||
8b417f2c PH |
1588 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1589 | * merely reformatted it into the Exim code style.) | |
1590 | ||
1591 | * "From here I changed the code to add support for multiple crl's | |
1592 | * in pem format in one file or to support hashed directory entries in | |
1593 | * pem format instead of a file. This method now uses the library function | |
1594 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1595 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1596 | * itself in the verify callback." */ | |
1597 | ||
059ec3d9 PH |
1598 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1599 | if (expcrl != NULL && *expcrl != 0) | |
1600 | { | |
8b417f2c PH |
1601 | struct stat statbufcrl; |
1602 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1603 | { | |
1604 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1605 | "failed to stat %s for certificates revocation lists", expcrl); | |
1606 | return DEFER; | |
1607 | } | |
1608 | else | |
059ec3d9 | 1609 | { |
8b417f2c PH |
1610 | /* is it a file or directory? */ |
1611 | uschar *file, *dir; | |
7be682ca | 1612 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1613 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1614 | { |
8b417f2c PH |
1615 | file = NULL; |
1616 | dir = expcrl; | |
1617 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1618 | } |
1619 | else | |
1620 | { | |
8b417f2c PH |
1621 | file = expcrl; |
1622 | dir = NULL; | |
1623 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1624 | } |
8b417f2c | 1625 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1626 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1627 | |
1628 | /* setting the flags to check against the complete crl chain */ | |
1629 | ||
1630 | X509_STORE_set_flags(cvstore, | |
1631 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1632 | } |
059ec3d9 PH |
1633 | } |
1634 | ||
1635 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1636 | ||
1637 | /* If verification is optional, don't fail if no certificate */ | |
1638 | ||
7be682ca | 1639 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1640 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 1641 | cert_vfy_cb); |
059ec3d9 PH |
1642 | } |
1643 | ||
1644 | return OK; | |
1645 | } | |
1646 | ||
1647 | ||
1648 | ||
1649 | /************************************************* | |
1650 | * Start a TLS session in a server * | |
1651 | *************************************************/ | |
1652 | ||
1653 | /* This is called when Exim is running as a server, after having received | |
1654 | the STARTTLS command. It must respond to that command, and then negotiate | |
1655 | a TLS session. | |
1656 | ||
1657 | Arguments: | |
1658 | require_ciphers allowed ciphers | |
1659 | ||
1660 | Returns: OK on success | |
1661 | DEFER for errors before the start of the negotiation | |
1662 | FAIL for errors during the negotation; the server can't | |
1663 | continue running. | |
1664 | */ | |
1665 | ||
1666 | int | |
17c76198 | 1667 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1668 | { |
1669 | int rc; | |
1670 | uschar *expciphers; | |
7be682ca | 1671 | tls_ext_ctx_cb *cbinfo; |
f69979cf | 1672 | static uschar peerdn[256]; |
817d9f57 | 1673 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1674 | |
1675 | /* Check for previous activation */ | |
1676 | ||
817d9f57 | 1677 | if (tls_in.active >= 0) |
059ec3d9 | 1678 | { |
5ca6d115 | 1679 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1680 | smtp_printf("554 Already in TLS\r\n"); |
1681 | return FAIL; | |
1682 | } | |
1683 | ||
1684 | /* Initialize the SSL library. If it fails, it will already have logged | |
1685 | the error. */ | |
1686 | ||
817d9f57 | 1687 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 1688 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1689 | tls_ocsp_file, |
1690 | #endif | |
817d9f57 | 1691 | NULL, &server_static_cbinfo); |
059ec3d9 | 1692 | if (rc != OK) return rc; |
817d9f57 | 1693 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1694 | |
1695 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1696 | return FAIL; | |
1697 | ||
1698 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1699 | were historically separated by underscores. So that I can use either form in my |
1700 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1701 | */ | |
059ec3d9 PH |
1702 | |
1703 | if (expciphers != NULL) | |
1704 | { | |
1705 | uschar *s = expciphers; | |
1706 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1707 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1708 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1709 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1710 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1711 | } |
1712 | ||
1713 | /* If this is a host for which certificate verification is mandatory or | |
1714 | optional, set up appropriately. */ | |
1715 | ||
817d9f57 | 1716 | tls_in.certificate_verified = FALSE; |
53a7196b JH |
1717 | #ifdef EXPERIMENTAL_DANE |
1718 | tls_in.dane_verified = FALSE; | |
1719 | #endif | |
a2ff477a | 1720 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1721 | |
1722 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1723 | { | |
983207c1 JH |
1724 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1725 | FALSE, verify_callback_server); | |
059ec3d9 | 1726 | if (rc != OK) return rc; |
a2ff477a | 1727 | server_verify_optional = FALSE; |
059ec3d9 PH |
1728 | } |
1729 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1730 | { | |
983207c1 JH |
1731 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1732 | TRUE, verify_callback_server); | |
059ec3d9 | 1733 | if (rc != OK) return rc; |
a2ff477a | 1734 | server_verify_optional = TRUE; |
059ec3d9 PH |
1735 | } |
1736 | ||
1737 | /* Prepare for new connection */ | |
1738 | ||
817d9f57 | 1739 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1740 | |
1741 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1742 | * | |
1743 | * With the SSL_clear(), we get strange interoperability bugs with | |
1744 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1745 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1746 | * | |
1747 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1748 | * session shutdown. In this case, we have a brand new object and there's no | |
1749 | * obvious reason to immediately clear it. I'm guessing that this was | |
1750 | * originally added because of incomplete initialisation which the clear fixed, | |
1751 | * in some historic release. | |
1752 | */ | |
059ec3d9 PH |
1753 | |
1754 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1755 | on connection, where outputting anything now upsets the clients and tends to | |
1756 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1757 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1758 | mode, the fflush() happens when smtp_getc() is called. */ | |
1759 | ||
817d9f57 JH |
1760 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1761 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1762 | { |
1763 | smtp_printf("220 TLS go ahead\r\n"); | |
1764 | fflush(smtp_out); | |
1765 | } | |
1766 | ||
1767 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1768 | that the OpenSSL library doesn't. */ | |
1769 | ||
817d9f57 JH |
1770 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1771 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1772 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1773 | |
1774 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1775 | ||
1776 | sigalrm_seen = FALSE; | |
1777 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1778 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1779 | alarm(0); |
1780 | ||
1781 | if (rc <= 0) | |
1782 | { | |
7199e1ee | 1783 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1784 | if (ERR_get_error() == 0) |
1785 | log_write(0, LOG_MAIN, | |
a053d125 | 1786 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1787 | return FAIL; |
1788 | } | |
1789 | ||
1790 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1791 | ||
1792 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1793 | and initialize things. */ | |
1794 | ||
f69979cf JH |
1795 | peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn)); |
1796 | ||
817d9f57 JH |
1797 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1798 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1799 | |
1800 | DEBUG(D_tls) | |
1801 | { | |
1802 | uschar buf[2048]; | |
817d9f57 | 1803 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1804 | debug_printf("Shared ciphers: %s\n", buf); |
1805 | } | |
1806 | ||
9d1c15ef JH |
1807 | /* Record the certificate we presented */ |
1808 | { | |
1809 | X509 * crt = SSL_get_certificate(server_ssl); | |
1810 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
1811 | } | |
059ec3d9 | 1812 | |
817d9f57 JH |
1813 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1814 | Client-side (tls_out) reads (seem to?) go via | |
1815 | smtp_read_response()/ip_recv(). | |
1816 | Hence no need to duplicate for _in and _out. | |
1817 | */ | |
059ec3d9 PH |
1818 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1819 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1820 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1821 | ||
1822 | receive_getc = tls_getc; | |
1823 | receive_ungetc = tls_ungetc; | |
1824 | receive_feof = tls_feof; | |
1825 | receive_ferror = tls_ferror; | |
58eb016e | 1826 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1827 | |
817d9f57 | 1828 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1829 | return OK; |
1830 | } | |
1831 | ||
1832 | ||
1833 | ||
1834 | ||
043b1248 JH |
1835 | static int |
1836 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
01a4a5c5 | 1837 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo |
043b1248 JH |
1838 | ) |
1839 | { | |
1840 | int rc; | |
94431adb | 1841 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
043b1248 JH |
1842 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only |
1843 | the specified host patterns if one of them is defined */ | |
1844 | ||
610ff438 JH |
1845 | if ( ( !ob->tls_verify_hosts |
1846 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
1847 | ) | |
5130845b | 1848 | || (verify_check_given_host(&ob->tls_verify_hosts, host) == OK) |
aa2a70ba | 1849 | ) |
043b1248 | 1850 | client_verify_optional = FALSE; |
5130845b | 1851 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
1852 | client_verify_optional = TRUE; |
1853 | else | |
1854 | return OK; | |
1855 | ||
1856 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
1857 | ob->tls_crl, host, client_verify_optional, verify_callback_client)) != OK) | |
1858 | return rc; | |
043b1248 | 1859 | |
5130845b | 1860 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 1861 | { |
4af0d74a | 1862 | cbinfo->verify_cert_hostnames = |
8c5d388a | 1863 | #ifdef SUPPORT_I18N |
4af0d74a JH |
1864 | string_domain_utf8_to_alabel(host->name, NULL); |
1865 | #else | |
1866 | host->name; | |
1867 | #endif | |
aa2a70ba JH |
1868 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", |
1869 | cbinfo->verify_cert_hostnames); | |
043b1248 | 1870 | } |
043b1248 JH |
1871 | return OK; |
1872 | } | |
059ec3d9 | 1873 | |
fde080a4 JH |
1874 | |
1875 | #ifdef EXPERIMENTAL_DANE | |
fde080a4 JH |
1876 | static int |
1877 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa) | |
1878 | { | |
1879 | dns_record * rr; | |
1880 | dns_scan dnss; | |
1881 | const char * hostnames[2] = { CS host->name, NULL }; | |
1882 | int found = 0; | |
1883 | ||
1884 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
1885 | return tls_error(US"hostnames load", host, NULL); | |
1886 | ||
1887 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); | |
1888 | rr; | |
1889 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
1890 | ) if (rr->type == T_TLSA) | |
1891 | { | |
1892 | uschar * p = rr->data; | |
1893 | uint8_t usage, selector, mtype; | |
1894 | const char * mdname; | |
1895 | ||
fde080a4 | 1896 | usage = *p++; |
133d2546 JH |
1897 | |
1898 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
1899 | if (usage != 2 && usage != 3) continue; | |
1900 | ||
fde080a4 JH |
1901 | selector = *p++; |
1902 | mtype = *p++; | |
1903 | ||
1904 | switch (mtype) | |
1905 | { | |
133d2546 JH |
1906 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
1907 | case 0: mdname = NULL; break; | |
1908 | case 1: mdname = "sha256"; break; | |
1909 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
1910 | } |
1911 | ||
133d2546 | 1912 | found++; |
fde080a4 JH |
1913 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
1914 | { | |
1915 | default: | |
1916 | case 0: /* action not taken */ | |
1917 | return tls_error(US"tlsa load", host, NULL); | |
1918 | case 1: break; | |
1919 | } | |
594706ea JH |
1920 | |
1921 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
1922 | } |
1923 | ||
1924 | if (found) | |
1925 | return OK; | |
1926 | ||
133d2546 | 1927 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 1928 | return DEFER; |
fde080a4 JH |
1929 | } |
1930 | #endif /*EXPERIMENTAL_DANE*/ | |
1931 | ||
1932 | ||
1933 | ||
059ec3d9 PH |
1934 | /************************************************* |
1935 | * Start a TLS session in a client * | |
1936 | *************************************************/ | |
1937 | ||
1938 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1939 | ||
1940 | Argument: | |
1941 | fd the fd of the connection | |
1942 | host connected host (for messages) | |
83da1223 | 1943 | addr the first address |
a7538db1 | 1944 | tb transport (always smtp) |
0e66b3b6 | 1945 | tlsa_dnsa tlsa lookup, if DANE, else null |
059ec3d9 PH |
1946 | |
1947 | Returns: OK on success | |
1948 | FAIL otherwise - note that tls_error() will not give DEFER | |
1949 | because this is not a server | |
1950 | */ | |
1951 | ||
1952 | int | |
f5d78688 | 1953 | tls_client_start(int fd, host_item *host, address_item *addr, |
0e66b3b6 JH |
1954 | transport_instance *tb |
1955 | #ifdef EXPERIMENTAL_DANE | |
1956 | , dns_answer * tlsa_dnsa | |
1957 | #endif | |
1958 | ) | |
059ec3d9 | 1959 | { |
a7538db1 JH |
1960 | smtp_transport_options_block * ob = |
1961 | (smtp_transport_options_block *)tb->options_block; | |
f69979cf | 1962 | static uschar peerdn[256]; |
868f5672 | 1963 | uschar * expciphers; |
059ec3d9 | 1964 | int rc; |
817d9f57 | 1965 | static uschar cipherbuf[256]; |
043b1248 JH |
1966 | |
1967 | #ifndef DISABLE_OCSP | |
043b1248 | 1968 | BOOL request_ocsp = FALSE; |
6634ac8d | 1969 | BOOL require_ocsp = FALSE; |
043b1248 | 1970 | #endif |
043b1248 JH |
1971 | |
1972 | #ifdef EXPERIMENTAL_DANE | |
594706ea | 1973 | tls_out.tlsa_usage = 0; |
043b1248 JH |
1974 | #endif |
1975 | ||
f2de3a33 | 1976 | #ifndef DISABLE_OCSP |
043b1248 | 1977 | { |
4f59c424 JH |
1978 | # ifdef EXPERIMENTAL_DANE |
1979 | if ( tlsa_dnsa | |
1980 | && ob->hosts_request_ocsp[0] == '*' | |
1981 | && ob->hosts_request_ocsp[1] == '\0' | |
1982 | ) | |
1983 | { | |
1984 | /* Unchanged from default. Use a safer one under DANE */ | |
1985 | request_ocsp = TRUE; | |
1986 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
1987 | " {= {4}{$tls_out_tlsa_usage}} } " | |
1988 | " {*}{}}"; | |
1989 | } | |
1990 | # endif | |
1991 | ||
5130845b JH |
1992 | if ((require_ocsp = |
1993 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK)) | |
fca41d5a JH |
1994 | request_ocsp = TRUE; |
1995 | else | |
fca41d5a | 1996 | # ifdef EXPERIMENTAL_DANE |
4f59c424 | 1997 | if (!request_ocsp) |
fca41d5a | 1998 | # endif |
5130845b JH |
1999 | request_ocsp = |
2000 | verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
043b1248 | 2001 | } |
f5d78688 | 2002 | #endif |
059ec3d9 | 2003 | |
65867078 JH |
2004 | rc = tls_init(&client_ctx, host, NULL, |
2005 | ob->tls_certificate, ob->tls_privatekey, | |
f2de3a33 | 2006 | #ifndef DISABLE_OCSP |
44662487 | 2007 | (void *)(long)request_ocsp, |
3f7eeb86 | 2008 | #endif |
817d9f57 | 2009 | addr, &client_static_cbinfo); |
059ec3d9 PH |
2010 | if (rc != OK) return rc; |
2011 | ||
817d9f57 | 2012 | tls_out.certificate_verified = FALSE; |
a2ff477a | 2013 | client_verify_callback_called = FALSE; |
059ec3d9 | 2014 | |
65867078 JH |
2015 | if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", |
2016 | &expciphers)) | |
059ec3d9 PH |
2017 | return FAIL; |
2018 | ||
2019 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
2020 | are separated by underscores. So that I can use either form in my tests, and | |
2021 | also for general convenience, we turn underscores into hyphens here. */ | |
2022 | ||
2023 | if (expciphers != NULL) | |
2024 | { | |
2025 | uschar *s = expciphers; | |
2026 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
2027 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 2028 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 2029 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
2030 | } |
2031 | ||
043b1248 | 2032 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 2033 | if (tlsa_dnsa) |
a63be306 | 2034 | { |
02af313d JH |
2035 | SSL_CTX_set_verify(client_ctx, |
2036 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, | |
2037 | verify_callback_client_dane); | |
e5cccda9 | 2038 | |
043b1248 | 2039 | if (!DANESSL_library_init()) |
b4161d10 | 2040 | return tls_error(US"library init", host, NULL); |
043b1248 | 2041 | if (DANESSL_CTX_init(client_ctx) <= 0) |
b4161d10 | 2042 | return tls_error(US"context init", host, NULL); |
043b1248 JH |
2043 | } |
2044 | else | |
e51c7be2 | 2045 | |
043b1248 JH |
2046 | #endif |
2047 | ||
01a4a5c5 JH |
2048 | if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob, client_static_cbinfo)) |
2049 | != OK) | |
65867078 | 2050 | return rc; |
059ec3d9 | 2051 | |
65867078 JH |
2052 | if ((client_ssl = SSL_new(client_ctx)) == NULL) |
2053 | return tls_error(US"SSL_new", host, NULL); | |
817d9f57 JH |
2054 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); |
2055 | SSL_set_fd(client_ssl, fd); | |
2056 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 2057 | |
65867078 | 2058 | if (ob->tls_sni) |
3f0945ff | 2059 | { |
65867078 | 2060 | if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 2061 | return FAIL; |
ec4b68e5 | 2062 | if (tls_out.sni == NULL) |
2c9a0e86 PP |
2063 | { |
2064 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
2065 | } | |
ec4b68e5 | 2066 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 2067 | tls_out.sni = NULL; |
3f0945ff PP |
2068 | else |
2069 | { | |
35731706 | 2070 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
2071 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
2072 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
2073 | #else |
2074 | DEBUG(D_tls) | |
2075 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
02d9264f | 2076 | tls_out.sni); |
35731706 | 2077 | #endif |
3f0945ff PP |
2078 | } |
2079 | } | |
2080 | ||
594706ea | 2081 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 JH |
2082 | if (tlsa_dnsa) |
2083 | if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa)) != OK) | |
594706ea JH |
2084 | return rc; |
2085 | #endif | |
2086 | ||
f2de3a33 | 2087 | #ifndef DISABLE_OCSP |
f5d78688 JH |
2088 | /* Request certificate status at connection-time. If the server |
2089 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
b50c8b84 | 2090 | # ifdef EXPERIMENTAL_DANE |
594706ea JH |
2091 | if (request_ocsp) |
2092 | { | |
2093 | const uschar * s; | |
41afb5cb JH |
2094 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
2095 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
2096 | ) |
2097 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
2098 | this means we avoid the OCSP request, we wasted the setup | |
2099 | cost in tls_init(). */ | |
5130845b JH |
2100 | require_ocsp = verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; |
2101 | request_ocsp = require_ocsp | |
2102 | || verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
594706ea JH |
2103 | } |
2104 | } | |
b50c8b84 JH |
2105 | # endif |
2106 | ||
44662487 JH |
2107 | if (request_ocsp) |
2108 | { | |
f5d78688 | 2109 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 JH |
2110 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
2111 | tls_out.ocsp = OCSP_NOT_RESP; | |
2112 | } | |
f5d78688 JH |
2113 | #endif |
2114 | ||
0cbf2b82 | 2115 | #ifndef DISABLE_EVENT |
774ef2d7 | 2116 | client_static_cbinfo->event_action = tb->event_action; |
a7538db1 | 2117 | #endif |
043b1248 | 2118 | |
059ec3d9 PH |
2119 | /* There doesn't seem to be a built-in timeout on connection. */ |
2120 | ||
2121 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
2122 | sigalrm_seen = FALSE; | |
65867078 | 2123 | alarm(ob->command_timeout); |
817d9f57 | 2124 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
2125 | alarm(0); |
2126 | ||
043b1248 | 2127 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 2128 | if (tlsa_dnsa) |
fde080a4 | 2129 | DANESSL_cleanup(client_ssl); |
043b1248 JH |
2130 | #endif |
2131 | ||
059ec3d9 | 2132 | if (rc <= 0) |
7199e1ee | 2133 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
2134 | |
2135 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
2136 | ||
f69979cf | 2137 | peer_cert(client_ssl, &tls_out, peerdn, sizeof(peerdn)); |
059ec3d9 | 2138 | |
817d9f57 JH |
2139 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
2140 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 2141 | |
9d1c15ef JH |
2142 | /* Record the certificate we presented */ |
2143 | { | |
2144 | X509 * crt = SSL_get_certificate(client_ssl); | |
2145 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
2146 | } | |
2147 | ||
817d9f57 | 2148 | tls_out.active = fd; |
059ec3d9 PH |
2149 | return OK; |
2150 | } | |
2151 | ||
2152 | ||
2153 | ||
2154 | ||
2155 | ||
2156 | /************************************************* | |
2157 | * TLS version of getc * | |
2158 | *************************************************/ | |
2159 | ||
2160 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2161 | it refills the buffer via the SSL reading function. | |
2162 | ||
2163 | Arguments: none | |
2164 | Returns: the next character or EOF | |
817d9f57 JH |
2165 | |
2166 | Only used by the server-side TLS. | |
059ec3d9 PH |
2167 | */ |
2168 | ||
2169 | int | |
2170 | tls_getc(void) | |
2171 | { | |
2172 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
2173 | { | |
2174 | int error; | |
2175 | int inbytes; | |
2176 | ||
817d9f57 | 2177 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 2178 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
2179 | |
2180 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
2181 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
2182 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
2183 | alarm(0); |
2184 | ||
2185 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2186 | closed down, not that the socket itself has been closed down. Revert to | |
2187 | non-SSL handling. */ | |
2188 | ||
2189 | if (error == SSL_ERROR_ZERO_RETURN) | |
2190 | { | |
2191 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2192 | ||
2193 | receive_getc = smtp_getc; | |
2194 | receive_ungetc = smtp_ungetc; | |
2195 | receive_feof = smtp_feof; | |
2196 | receive_ferror = smtp_ferror; | |
58eb016e | 2197 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 2198 | |
817d9f57 JH |
2199 | SSL_free(server_ssl); |
2200 | server_ssl = NULL; | |
2201 | tls_in.active = -1; | |
2202 | tls_in.bits = 0; | |
2203 | tls_in.cipher = NULL; | |
2204 | tls_in.peerdn = NULL; | |
2205 | tls_in.sni = NULL; | |
059ec3d9 PH |
2206 | |
2207 | return smtp_getc(); | |
2208 | } | |
2209 | ||
2210 | /* Handle genuine errors */ | |
2211 | ||
ba084640 PP |
2212 | else if (error == SSL_ERROR_SSL) |
2213 | { | |
2214 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 2215 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
2216 | ssl_xfer_error = 1; |
2217 | return EOF; | |
2218 | } | |
2219 | ||
059ec3d9 PH |
2220 | else if (error != SSL_ERROR_NONE) |
2221 | { | |
2222 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2223 | ssl_xfer_error = 1; | |
2224 | return EOF; | |
2225 | } | |
c80c5570 | 2226 | |
80a47a2c TK |
2227 | #ifndef DISABLE_DKIM |
2228 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2229 | #endif | |
059ec3d9 PH |
2230 | ssl_xfer_buffer_hwm = inbytes; |
2231 | ssl_xfer_buffer_lwm = 0; | |
2232 | } | |
2233 | ||
2234 | /* Something in the buffer; return next uschar */ | |
2235 | ||
2236 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
2237 | } | |
2238 | ||
2239 | ||
2240 | ||
2241 | /************************************************* | |
2242 | * Read bytes from TLS channel * | |
2243 | *************************************************/ | |
2244 | ||
2245 | /* | |
2246 | Arguments: | |
2247 | buff buffer of data | |
2248 | len size of buffer | |
2249 | ||
2250 | Returns: the number of bytes read | |
2251 | -1 after a failed read | |
817d9f57 JH |
2252 | |
2253 | Only used by the client-side TLS. | |
059ec3d9 PH |
2254 | */ |
2255 | ||
2256 | int | |
389ca47a | 2257 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2258 | { |
389ca47a | 2259 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
2260 | int inbytes; |
2261 | int error; | |
2262 | ||
389ca47a | 2263 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2264 | buff, (unsigned int)len); |
059ec3d9 | 2265 | |
389ca47a JH |
2266 | inbytes = SSL_read(ssl, CS buff, len); |
2267 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2268 | |
2269 | if (error == SSL_ERROR_ZERO_RETURN) | |
2270 | { | |
2271 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2272 | return -1; | |
2273 | } | |
2274 | else if (error != SSL_ERROR_NONE) | |
2275 | { | |
2276 | return -1; | |
2277 | } | |
2278 | ||
2279 | return inbytes; | |
2280 | } | |
2281 | ||
2282 | ||
2283 | ||
2284 | ||
2285 | ||
2286 | /************************************************* | |
2287 | * Write bytes down TLS channel * | |
2288 | *************************************************/ | |
2289 | ||
2290 | /* | |
2291 | Arguments: | |
817d9f57 | 2292 | is_server channel specifier |
059ec3d9 PH |
2293 | buff buffer of data |
2294 | len number of bytes | |
2295 | ||
2296 | Returns: the number of bytes after a successful write, | |
2297 | -1 after a failed write | |
817d9f57 JH |
2298 | |
2299 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2300 | */ |
2301 | ||
2302 | int | |
817d9f57 | 2303 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
2304 | { |
2305 | int outbytes; | |
2306 | int error; | |
2307 | int left = len; | |
817d9f57 | 2308 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 2309 | |
c80c5570 | 2310 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
2311 | while (left > 0) |
2312 | { | |
c80c5570 | 2313 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
2314 | outbytes = SSL_write(ssl, CS buff, left); |
2315 | error = SSL_get_error(ssl, outbytes); | |
2316 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2317 | switch (error) | |
2318 | { | |
2319 | case SSL_ERROR_SSL: | |
2320 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2321 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
2322 | return -1; | |
2323 | ||
2324 | case SSL_ERROR_NONE: | |
2325 | left -= outbytes; | |
2326 | buff += outbytes; | |
2327 | break; | |
2328 | ||
2329 | case SSL_ERROR_ZERO_RETURN: | |
2330 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
2331 | return -1; | |
2332 | ||
817d9f57 JH |
2333 | case SSL_ERROR_SYSCALL: |
2334 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
2335 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
2336 | strerror(errno)); | |
2337 | ||
059ec3d9 PH |
2338 | default: |
2339 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
2340 | return -1; | |
2341 | } | |
2342 | } | |
2343 | return len; | |
2344 | } | |
2345 | ||
2346 | ||
2347 | ||
2348 | /************************************************* | |
2349 | * Close down a TLS session * | |
2350 | *************************************************/ | |
2351 | ||
2352 | /* This is also called from within a delivery subprocess forked from the | |
2353 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2354 | would tamper with the SSL session in the parent process). | |
2355 | ||
2356 | Arguments: TRUE if SSL_shutdown is to be called | |
2357 | Returns: nothing | |
817d9f57 JH |
2358 | |
2359 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2360 | */ |
2361 | ||
2362 | void | |
817d9f57 | 2363 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2364 | { |
817d9f57 | 2365 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 2366 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
2367 | |
2368 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
2369 | |
2370 | if (shutdown) | |
2371 | { | |
2372 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 2373 | SSL_shutdown(*sslp); |
059ec3d9 PH |
2374 | } |
2375 | ||
817d9f57 JH |
2376 | SSL_free(*sslp); |
2377 | *sslp = NULL; | |
059ec3d9 | 2378 | |
817d9f57 | 2379 | *fdp = -1; |
059ec3d9 PH |
2380 | } |
2381 | ||
36f12725 NM |
2382 | |
2383 | ||
2384 | ||
3375e053 PP |
2385 | /************************************************* |
2386 | * Let tls_require_ciphers be checked at startup * | |
2387 | *************************************************/ | |
2388 | ||
2389 | /* The tls_require_ciphers option, if set, must be something which the | |
2390 | library can parse. | |
2391 | ||
2392 | Returns: NULL on success, or error message | |
2393 | */ | |
2394 | ||
2395 | uschar * | |
2396 | tls_validate_require_cipher(void) | |
2397 | { | |
2398 | SSL_CTX *ctx; | |
2399 | uschar *s, *expciphers, *err; | |
2400 | ||
2401 | /* this duplicates from tls_init(), we need a better "init just global | |
2402 | state, for no specific purpose" singleton function of our own */ | |
2403 | ||
2404 | SSL_load_error_strings(); | |
2405 | OpenSSL_add_ssl_algorithms(); | |
2406 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
2407 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
2408 | list of available digests. */ | |
2409 | EVP_add_digest(EVP_sha256()); | |
2410 | #endif | |
2411 | ||
2412 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2413 | return NULL; | |
2414 | ||
2415 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2416 | return US"failed to expand tls_require_ciphers"; | |
2417 | ||
2418 | if (!(expciphers && *expciphers)) | |
2419 | return NULL; | |
2420 | ||
2421 | /* normalisation ripped from above */ | |
2422 | s = expciphers; | |
2423 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
2424 | ||
2425 | err = NULL; | |
2426 | ||
2427 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
2428 | if (!ctx) | |
2429 | { | |
2430 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2431 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
2432 | } | |
2433 | ||
2434 | DEBUG(D_tls) | |
2435 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2436 | ||
2437 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
2438 | { | |
2439 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2440 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
2441 | } | |
2442 | ||
2443 | SSL_CTX_free(ctx); | |
2444 | ||
2445 | return err; | |
2446 | } | |
2447 | ||
2448 | ||
2449 | ||
2450 | ||
36f12725 NM |
2451 | /************************************************* |
2452 | * Report the library versions. * | |
2453 | *************************************************/ | |
2454 | ||
2455 | /* There have historically been some issues with binary compatibility in | |
2456 | OpenSSL libraries; if Exim (like many other applications) is built against | |
2457 | one version of OpenSSL but the run-time linker picks up another version, | |
2458 | it can result in serious failures, including crashing with a SIGSEGV. So | |
2459 | report the version found by the compiler and the run-time version. | |
2460 | ||
f64a1e23 PP |
2461 | Note: some OS vendors backport security fixes without changing the version |
2462 | number/string, and the version date remains unchanged. The _build_ date | |
2463 | will change, so we can more usefully assist with version diagnosis by also | |
2464 | reporting the build date. | |
2465 | ||
36f12725 NM |
2466 | Arguments: a FILE* to print the results to |
2467 | Returns: nothing | |
2468 | */ | |
2469 | ||
2470 | void | |
2471 | tls_version_report(FILE *f) | |
2472 | { | |
754a0503 | 2473 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
2474 | " Runtime: %s\n" |
2475 | " : %s\n", | |
754a0503 | 2476 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
2477 | SSLeay_version(SSLEAY_VERSION), |
2478 | SSLeay_version(SSLEAY_BUILT_ON)); | |
2479 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
2480 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
2481 | } |
2482 | ||
9e3331ea TK |
2483 | |
2484 | ||
2485 | ||
2486 | /************************************************* | |
17c76198 | 2487 | * Random number generation * |
9e3331ea TK |
2488 | *************************************************/ |
2489 | ||
2490 | /* Pseudo-random number generation. The result is not expected to be | |
2491 | cryptographically strong but not so weak that someone will shoot themselves | |
2492 | in the foot using it as a nonce in input in some email header scheme or | |
2493 | whatever weirdness they'll twist this into. The result should handle fork() | |
2494 | and avoid repeating sequences. OpenSSL handles that for us. | |
2495 | ||
2496 | Arguments: | |
2497 | max range maximum | |
2498 | Returns a random number in range [0, max-1] | |
2499 | */ | |
2500 | ||
2501 | int | |
17c76198 | 2502 | vaguely_random_number(int max) |
9e3331ea TK |
2503 | { |
2504 | unsigned int r; | |
2505 | int i, needed_len; | |
de6135a0 PP |
2506 | static pid_t pidlast = 0; |
2507 | pid_t pidnow; | |
9e3331ea TK |
2508 | uschar *p; |
2509 | uschar smallbuf[sizeof(r)]; | |
2510 | ||
2511 | if (max <= 1) | |
2512 | return 0; | |
2513 | ||
de6135a0 PP |
2514 | pidnow = getpid(); |
2515 | if (pidnow != pidlast) | |
2516 | { | |
2517 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2518 | is unique for each thread", this doesn't apparently apply across processes, | |
2519 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2520 | Fix per PostgreSQL. */ | |
2521 | if (pidlast != 0) | |
2522 | RAND_cleanup(); | |
2523 | pidlast = pidnow; | |
2524 | } | |
2525 | ||
9e3331ea TK |
2526 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
2527 | if (!RAND_status()) | |
2528 | { | |
2529 | randstuff r; | |
2530 | gettimeofday(&r.tv, NULL); | |
2531 | r.p = getpid(); | |
2532 | ||
2533 | RAND_seed((uschar *)(&r), sizeof(r)); | |
2534 | } | |
2535 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2536 | in the internal PRNG then our options are limited. We could sleep and hope | |
2537 | for entropy to come along (prayer technique) but if the system is so depleted | |
2538 | in the first place then something is likely to just keep taking it. Instead, | |
2539 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2540 | get. */ | |
2541 | ||
2542 | needed_len = sizeof(r); | |
2543 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2544 | asked for a number less than 10. */ | |
2545 | for (r = max, i = 0; r; ++i) | |
2546 | r >>= 1; | |
2547 | i = (i + 7) / 8; | |
2548 | if (i < needed_len) | |
2549 | needed_len = i; | |
2550 | ||
2551 | /* We do not care if crypto-strong */ | |
17c76198 PP |
2552 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
2553 | if (i < 0) | |
2554 | { | |
2555 | DEBUG(D_all) | |
2556 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2557 | return vaguely_random_number_fallback(max); | |
2558 | } | |
2559 | ||
9e3331ea TK |
2560 | r = 0; |
2561 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2562 | { | |
2563 | r *= 256; | |
2564 | r += *p; | |
2565 | } | |
2566 | ||
2567 | /* We don't particularly care about weighted results; if someone wants | |
2568 | smooth distribution and cares enough then they should submit a patch then. */ | |
2569 | return r % max; | |
2570 | } | |
2571 | ||
77bb000f PP |
2572 | |
2573 | ||
2574 | ||
2575 | /************************************************* | |
2576 | * OpenSSL option parse * | |
2577 | *************************************************/ | |
2578 | ||
2579 | /* Parse one option for tls_openssl_options_parse below | |
2580 | ||
2581 | Arguments: | |
2582 | name one option name | |
2583 | value place to store a value for it | |
2584 | Returns success or failure in parsing | |
2585 | */ | |
2586 | ||
2587 | struct exim_openssl_option { | |
2588 | uschar *name; | |
2589 | long value; | |
2590 | }; | |
2591 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2592 | options document which version they were introduced in. Policylet: include | |
2593 | all options unless explicitly for DTLS, let the administrator choose which | |
2594 | to apply. | |
2595 | ||
2596 | This list is current as of: | |
e2fbf4a2 PP |
2597 | ==> 1.0.1b <== |
2598 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2599 | */ | |
77bb000f PP |
2600 | static struct exim_openssl_option exim_openssl_options[] = { |
2601 | /* KEEP SORTED ALPHABETICALLY! */ | |
2602 | #ifdef SSL_OP_ALL | |
73a46702 | 2603 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2604 | #endif |
2605 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2606 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2607 | #endif |
2608 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2609 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2610 | #endif |
2611 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2612 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2613 | #endif |
2614 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2615 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2616 | #endif |
2617 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2618 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2619 | #endif |
2620 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2621 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2622 | #endif |
2623 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2624 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2625 | #endif |
2626 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2627 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2628 | #endif |
2629 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2630 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2631 | #endif |
2632 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2633 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2634 | #endif |
c80c5570 PP |
2635 | #ifdef SSL_OP_NO_COMPRESSION |
2636 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2637 | #endif | |
77bb000f | 2638 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2639 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2640 | #endif |
c0c7b2da PP |
2641 | #ifdef SSL_OP_NO_SSLv2 |
2642 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2643 | #endif | |
2644 | #ifdef SSL_OP_NO_SSLv3 | |
2645 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2646 | #endif | |
2647 | #ifdef SSL_OP_NO_TICKET | |
2648 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2649 | #endif | |
2650 | #ifdef SSL_OP_NO_TLSv1 | |
2651 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2652 | #endif | |
c80c5570 PP |
2653 | #ifdef SSL_OP_NO_TLSv1_1 |
2654 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2655 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2656 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2657 | #else | |
2658 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2659 | #endif | |
2660 | #endif | |
2661 | #ifdef SSL_OP_NO_TLSv1_2 | |
2662 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2663 | #endif | |
e2fbf4a2 PP |
2664 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG |
2665 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2666 | #endif | |
77bb000f | 2667 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2668 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2669 | #endif |
2670 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2671 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2672 | #endif |
2673 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2674 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2675 | #endif |
2676 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2677 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2678 | #endif |
2679 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2680 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2681 | #endif |
2682 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2683 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2684 | #endif |
2685 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2686 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2687 | #endif |
2688 | }; | |
2689 | static int exim_openssl_options_size = | |
2690 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2691 | ||
c80c5570 | 2692 | |
77bb000f PP |
2693 | static BOOL |
2694 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2695 | { | |
2696 | int first = 0; | |
2697 | int last = exim_openssl_options_size; | |
2698 | while (last > first) | |
2699 | { | |
2700 | int middle = (first + last)/2; | |
2701 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2702 | if (c == 0) | |
2703 | { | |
2704 | *value = exim_openssl_options[middle].value; | |
2705 | return TRUE; | |
2706 | } | |
2707 | else if (c > 0) | |
2708 | first = middle + 1; | |
2709 | else | |
2710 | last = middle; | |
2711 | } | |
2712 | return FALSE; | |
2713 | } | |
2714 | ||
2715 | ||
2716 | ||
2717 | ||
2718 | /************************************************* | |
2719 | * OpenSSL option parsing logic * | |
2720 | *************************************************/ | |
2721 | ||
2722 | /* OpenSSL has a number of compatibility options which an administrator might | |
2723 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2724 | we look like log_selector. | |
2725 | ||
2726 | Arguments: | |
2727 | option_spec the administrator-supplied string of options | |
2728 | results ptr to long storage for the options bitmap | |
2729 | Returns success or failure | |
2730 | */ | |
2731 | ||
2732 | BOOL | |
2733 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2734 | { | |
2735 | long result, item; | |
2736 | uschar *s, *end; | |
2737 | uschar keep_c; | |
2738 | BOOL adding, item_parsed; | |
2739 | ||
0e944a0d | 2740 | result = 0L; |
b1770b6e | 2741 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 2742 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
2743 | #ifdef SSL_OP_NO_SSLv2 |
2744 | result |= SSL_OP_NO_SSLv2; | |
2745 | #endif | |
77bb000f PP |
2746 | |
2747 | if (option_spec == NULL) | |
2748 | { | |
2749 | *results = result; | |
2750 | return TRUE; | |
2751 | } | |
2752 | ||
2753 | for (s=option_spec; *s != '\0'; /**/) | |
2754 | { | |
2755 | while (isspace(*s)) ++s; | |
2756 | if (*s == '\0') | |
2757 | break; | |
2758 | if (*s != '+' && *s != '-') | |
2759 | { | |
2760 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 2761 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
2762 | return FALSE; |
2763 | } | |
2764 | adding = *s++ == '+'; | |
2765 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2766 | keep_c = *end; | |
2767 | *end = '\0'; | |
2768 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2769 | if (!item_parsed) | |
2770 | { | |
0e944a0d | 2771 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
2772 | return FALSE; |
2773 | } | |
2774 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2775 | adding ? "adding" : "removing", result, item, s); | |
2776 | if (adding) | |
2777 | result |= item; | |
2778 | else | |
2779 | result &= ~item; | |
2780 | *end = keep_c; | |
2781 | s = end; | |
2782 | } | |
2783 | ||
2784 | *results = result; | |
2785 | return TRUE; | |
2786 | } | |
2787 | ||
9d1c15ef JH |
2788 | /* vi: aw ai sw=2 |
2789 | */ | |
059ec3d9 | 2790 | /* End of tls-openssl.c */ |