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> | |
f2de3a33 | 25 | #ifndef DISABLE_OCSP |
e51c7be2 | 26 | # include <openssl/ocsp.h> |
3f7eeb86 | 27 | #endif |
85098ee7 JH |
28 | #ifdef EXPERIMENTAL_DANE |
29 | # include <danessl.h> | |
30 | #endif | |
31 | ||
3f7eeb86 | 32 | |
f2de3a33 JH |
33 | #ifndef DISABLE_OCSP |
34 | # define EXIM_OCSP_SKEW_SECONDS (300L) | |
35 | # define EXIM_OCSP_MAX_AGE (-1L) | |
3f7eeb86 | 36 | #endif |
059ec3d9 | 37 | |
3bcbbbe2 | 38 | #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) |
e51c7be2 | 39 | # define EXIM_HAVE_OPENSSL_TLSEXT |
3bcbbbe2 | 40 | #endif |
34e3241d PP |
41 | |
42 | /* | |
43 | * X509_check_host provides sane certificate hostname checking, but was added | |
44 | * to OpenSSL late, after other projects forked off the code-base. So in | |
45 | * addition to guarding against the base version number, beware that LibreSSL | |
46 | * does not (at this time) support this function. | |
47 | * | |
48 | * If LibreSSL gains a different API, perhaps via libtls, then we'll probably | |
49 | * opt to disentangle and ask a LibreSSL user to provide glue for a third | |
50 | * crypto provider for libtls instead of continuing to tie the OpenSSL glue | |
51 | * into even twistier knots. If LibreSSL gains the same API, we can just | |
52 | * change this guard and punt the issue for a while longer. | |
53 | */ | |
54 | #ifndef LIBRESSL_VERSION_NUMBER | |
55 | # if OPENSSL_VERSION_NUMBER >= 0x010100000L | |
56 | # define EXIM_HAVE_OPENSSL_CHECKHOST | |
57 | # endif | |
58 | # if OPENSSL_VERSION_NUMBER >= 0x010000000L \ | |
2dfb468b | 59 | && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L |
34e3241d PP |
60 | # define EXIM_HAVE_OPENSSL_CHECKHOST |
61 | # endif | |
2dfb468b | 62 | #endif |
3bcbbbe2 | 63 | |
67791ce4 JH |
64 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
65 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
66 | # define DISABLE_OCSP | |
67 | #endif | |
68 | ||
059ec3d9 PH |
69 | /* Structure for collecting random data for seeding. */ |
70 | ||
71 | typedef struct randstuff { | |
9e3331ea TK |
72 | struct timeval tv; |
73 | pid_t p; | |
059ec3d9 PH |
74 | } randstuff; |
75 | ||
76 | /* Local static variables */ | |
77 | ||
a2ff477a JH |
78 | static BOOL client_verify_callback_called = FALSE; |
79 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
80 | static const uschar *sid_ctx = US"exim"; |
81 | ||
d4f09789 PP |
82 | /* We have three different contexts to care about. |
83 | ||
84 | Simple case: client, `client_ctx` | |
85 | As a client, we can be doing a callout or cut-through delivery while receiving | |
86 | a message. So we have a client context, which should have options initialised | |
87 | from the SMTP Transport. | |
88 | ||
89 | Server: | |
90 | There are two cases: with and without ServerNameIndication from the client. | |
91 | Given TLS SNI, we can be using different keys, certs and various other | |
92 | configuration settings, because they're re-expanded with $tls_sni set. This | |
93 | allows vhosting with TLS. This SNI is sent in the handshake. | |
94 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
95 | So as a server, we start out using `server_ctx`. | |
96 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
97 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
98 | configuration. | |
99 | */ | |
100 | ||
817d9f57 JH |
101 | static SSL_CTX *client_ctx = NULL; |
102 | static SSL_CTX *server_ctx = NULL; | |
103 | static SSL *client_ssl = NULL; | |
104 | static SSL *server_ssl = NULL; | |
389ca47a | 105 | |
35731706 | 106 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 107 | static SSL_CTX *server_sni = NULL; |
35731706 | 108 | #endif |
059ec3d9 PH |
109 | |
110 | static char ssl_errstring[256]; | |
111 | ||
112 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
113 | static BOOL client_verify_optional = FALSE; |
114 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 115 | |
f5d78688 | 116 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
117 | |
118 | ||
7be682ca PP |
119 | typedef struct tls_ext_ctx_cb { |
120 | uschar *certificate; | |
121 | uschar *privatekey; | |
f2de3a33 | 122 | #ifndef DISABLE_OCSP |
f5d78688 JH |
123 | BOOL is_server; |
124 | union { | |
125 | struct { | |
126 | uschar *file; | |
127 | uschar *file_expanded; | |
128 | OCSP_RESPONSE *response; | |
129 | } server; | |
130 | struct { | |
44662487 JH |
131 | X509_STORE *verify_store; /* non-null if status requested */ |
132 | BOOL verify_required; | |
f5d78688 JH |
133 | } client; |
134 | } u_ocsp; | |
3f7eeb86 | 135 | #endif |
7be682ca PP |
136 | uschar *dhparam; |
137 | /* these are cached from first expand */ | |
138 | uschar *server_cipher_list; | |
139 | /* only passed down to tls_error: */ | |
140 | host_item *host; | |
55414b25 | 141 | const uschar * verify_cert_hostnames; |
774ef2d7 | 142 | #ifdef EXPERIMENTAL_EVENT |
a7538db1 JH |
143 | uschar * event_action; |
144 | #endif | |
7be682ca PP |
145 | } tls_ext_ctx_cb; |
146 | ||
147 | /* should figure out a cleanup of API to handle state preserved per | |
148 | implementation, for various reasons, which can be void * in the APIs. | |
149 | For now, we hack around it. */ | |
817d9f57 JH |
150 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
151 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
152 | |
153 | static int | |
983207c1 JH |
154 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
155 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ); | |
059ec3d9 | 156 | |
3f7eeb86 | 157 | /* Callbacks */ |
3bcbbbe2 | 158 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 159 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 160 | #endif |
f2de3a33 | 161 | #ifndef DISABLE_OCSP |
f5d78688 | 162 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
163 | #endif |
164 | ||
059ec3d9 PH |
165 | |
166 | /************************************************* | |
167 | * Handle TLS error * | |
168 | *************************************************/ | |
169 | ||
170 | /* Called from lots of places when errors occur before actually starting to do | |
171 | the TLS handshake, that is, while the session is still in clear. Always returns | |
172 | DEFER for a server and FAIL for a client so that most calls can use "return | |
173 | tls_error(...)" to do this processing and then give an appropriate return. A | |
174 | single function is used for both server and client, because it is called from | |
175 | some shared functions. | |
176 | ||
177 | Argument: | |
178 | prefix text to include in the logged error | |
179 | host NULL if setting up a server; | |
180 | the connected host if setting up a client | |
7199e1ee | 181 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
182 | |
183 | Returns: OK/DEFER/FAIL | |
184 | */ | |
185 | ||
186 | static int | |
b8b1b5cb | 187 | tls_error(uschar * prefix, const host_item * host, uschar * msg) |
059ec3d9 | 188 | { |
c562fd30 | 189 | if (!msg) |
7199e1ee TF |
190 | { |
191 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 192 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
193 | } |
194 | ||
c562fd30 JH |
195 | if (host) |
196 | { | |
197 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s): %s", | |
198 | host->name, host->address, prefix, msg); | |
199 | return FAIL; | |
200 | } | |
201 | else | |
059ec3d9 | 202 | { |
7199e1ee | 203 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 204 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee | 205 | conn_info += 5; |
c562fd30 | 206 | /* I'd like to get separated H= here, but too hard for now */ |
7199e1ee TF |
207 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", |
208 | conn_info, prefix, msg); | |
059ec3d9 PH |
209 | return DEFER; |
210 | } | |
059ec3d9 PH |
211 | } |
212 | ||
213 | ||
214 | ||
215 | /************************************************* | |
216 | * Callback to generate RSA key * | |
217 | *************************************************/ | |
218 | ||
219 | /* | |
220 | Arguments: | |
221 | s SSL connection | |
222 | export not used | |
223 | keylength keylength | |
224 | ||
225 | Returns: pointer to generated key | |
226 | */ | |
227 | ||
228 | static RSA * | |
229 | rsa_callback(SSL *s, int export, int keylength) | |
230 | { | |
231 | RSA *rsa_key; | |
232 | export = export; /* Shut picky compilers up */ | |
233 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
234 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
235 | if (rsa_key == NULL) | |
236 | { | |
237 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
238 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
239 | ssl_errstring); | |
240 | return NULL; | |
241 | } | |
242 | return rsa_key; | |
243 | } | |
244 | ||
245 | ||
246 | ||
f5d78688 | 247 | /* Extreme debug |
f2de3a33 | 248 | #ifndef DISABLE_OCSP |
f5d78688 JH |
249 | void |
250 | x509_store_dump_cert_s_names(X509_STORE * store) | |
251 | { | |
252 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
253 | int i; | |
254 | static uschar name[256]; | |
255 | ||
256 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
257 | { | |
258 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
259 | if(tmp_obj->type == X509_LU_X509) | |
260 | { | |
261 | X509 * current_cert= tmp_obj->data.x509; | |
262 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
f69979cf | 263 | name[sizeof(name)-1] = '\0'; |
f5d78688 JH |
264 | debug_printf(" %s\n", name); |
265 | } | |
266 | } | |
267 | } | |
268 | #endif | |
269 | */ | |
270 | ||
059ec3d9 | 271 | |
f69979cf JH |
272 | #ifdef EXPERIMENTAL_EVENT |
273 | static int | |
274 | verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn, | |
275 | BOOL *calledp, const BOOL *optionalp, const uschar * what) | |
276 | { | |
277 | uschar * ev; | |
278 | uschar * yield; | |
279 | X509 * old_cert; | |
280 | ||
281 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; | |
282 | if (ev) | |
283 | { | |
284 | old_cert = tlsp->peercert; | |
285 | tlsp->peercert = X509_dup(cert); | |
286 | /* NB we do not bother setting peerdn */ | |
287 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) | |
288 | { | |
289 | log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: " | |
290 | "depth=%d cert=%s: %s", | |
291 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
292 | what, depth, dn, yield); | |
293 | *calledp = TRUE; | |
294 | if (!*optionalp) | |
295 | { | |
296 | if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */ | |
297 | return 1; /* reject (leaving peercert set) */ | |
298 | } | |
299 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
300 | "(host in tls_try_verify_hosts)\n"); | |
301 | } | |
302 | X509_free(tlsp->peercert); | |
303 | tlsp->peercert = old_cert; | |
304 | } | |
305 | return 0; | |
306 | } | |
307 | #endif | |
308 | ||
059ec3d9 PH |
309 | /************************************************* |
310 | * Callback for verification * | |
311 | *************************************************/ | |
312 | ||
313 | /* The SSL library does certificate verification if set up to do so. This | |
314 | callback has the current yes/no state is in "state". If verification succeeded, | |
f69979cf JH |
315 | we set the certificate-verified flag. If verification failed, what happens |
316 | depends on whether the client is required to present a verifiable certificate | |
317 | or not. | |
059ec3d9 PH |
318 | |
319 | If verification is optional, we change the state to yes, but still log the | |
320 | verification error. For some reason (it really would help to have proper | |
321 | documentation of OpenSSL), this callback function then gets called again, this | |
f69979cf JH |
322 | time with state = 1. We must take care not to set the private verified flag on |
323 | the second time through. | |
059ec3d9 PH |
324 | |
325 | Note: this function is not called if the client fails to present a certificate | |
326 | when asked. We get here only if a certificate has been received. Handling of | |
327 | optional verification for this case is done when requesting SSL to verify, by | |
328 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
329 | ||
a7538db1 JH |
330 | May be called multiple times for different issues with a certificate, even |
331 | for a given "depth" in the certificate chain. | |
332 | ||
059ec3d9 PH |
333 | Arguments: |
334 | state current yes/no state as 1/0 | |
335 | x509ctx certificate information. | |
a2ff477a | 336 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
337 | |
338 | Returns: 1 if verified, 0 if not | |
339 | */ | |
340 | ||
341 | static int | |
421aff85 JH |
342 | verify_callback(int state, X509_STORE_CTX *x509ctx, |
343 | tls_support *tlsp, BOOL *calledp, BOOL *optionalp) | |
059ec3d9 | 344 | { |
421aff85 | 345 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 346 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 347 | uschar dn[256]; |
059ec3d9 | 348 | |
f69979cf JH |
349 | X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn)); |
350 | dn[sizeof(dn)-1] = '\0'; | |
059ec3d9 PH |
351 | |
352 | if (state == 0) | |
353 | { | |
4c01d6ab JH |
354 | log_write(0, LOG_MAIN, "[%s] SSL verify error: depth=%d error=%s cert=%s", |
355 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
a7538db1 | 356 | depth, |
421aff85 | 357 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), |
f69979cf | 358 | dn); |
a2ff477a | 359 | *calledp = TRUE; |
9d1c15ef JH |
360 | if (!*optionalp) |
361 | { | |
f69979cf JH |
362 | if (!tlsp->peercert) |
363 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
364 | return 0; /* reject */ | |
9d1c15ef | 365 | } |
059ec3d9 PH |
366 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
367 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
368 | } |
369 | ||
a7538db1 | 370 | else if (depth != 0) |
059ec3d9 | 371 | { |
f69979cf | 372 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn); |
f2de3a33 | 373 | #ifndef DISABLE_OCSP |
f5d78688 JH |
374 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
375 | { /* client, wanting stapling */ | |
376 | /* Add the server cert's signing chain as the one | |
377 | for the verification of the OCSP stapled information. */ | |
378 | ||
379 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
421aff85 | 380 | cert)) |
f5d78688 JH |
381 | ERR_clear_error(); |
382 | } | |
a7538db1 | 383 | #endif |
774ef2d7 | 384 | #ifdef EXPERIMENTAL_EVENT |
f69979cf JH |
385 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
386 | return 0; /* reject, with peercert set */ | |
f5d78688 | 387 | #endif |
059ec3d9 PH |
388 | } |
389 | else | |
390 | { | |
55414b25 | 391 | const uschar * verify_cert_hostnames; |
e51c7be2 | 392 | |
e51c7be2 JH |
393 | if ( tlsp == &tls_out |
394 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
395 | /* client, wanting hostname check */ | |
e51c7be2 | 396 | { |
f69979cf | 397 | |
740f36d4 | 398 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
f69979cf JH |
399 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
400 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
401 | # endif | |
402 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
403 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
404 | # endif | |
e51c7be2 | 405 | int sep = 0; |
55414b25 | 406 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 407 | uschar * name; |
d8e7834a JH |
408 | int rc; |
409 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
410 | if ((rc = X509_check_host(cert, name, 0, | |
8d692470 | 411 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
740f36d4 JH |
412 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS, |
413 | NULL))) | |
d8e7834a JH |
414 | { |
415 | if (rc < 0) | |
416 | { | |
93a6fce2 | 417 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
4c01d6ab | 418 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
419 | name = NULL; |
420 | } | |
e51c7be2 | 421 | break; |
d8e7834a | 422 | } |
e51c7be2 | 423 | if (!name) |
f69979cf | 424 | #else |
e51c7be2 | 425 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) |
f69979cf | 426 | #endif |
e51c7be2 JH |
427 | { |
428 | log_write(0, LOG_MAIN, | |
93a6fce2 | 429 | "[%s] SSL verify error: certificate name mismatch: \"%s\"", |
4c01d6ab | 430 | tlsp == &tls_out ? deliver_host_address : sender_host_address, |
f69979cf | 431 | dn); |
a3ef7310 JH |
432 | *calledp = TRUE; |
433 | if (!*optionalp) | |
f69979cf JH |
434 | { |
435 | if (!tlsp->peercert) | |
436 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
437 | return 0; /* reject */ | |
438 | } | |
a3ef7310 JH |
439 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
440 | "tls_try_verify_hosts)\n"); | |
e51c7be2 | 441 | } |
f69979cf | 442 | } |
e51c7be2 | 443 | |
774ef2d7 | 444 | #ifdef EXPERIMENTAL_EVENT |
f69979cf JH |
445 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
446 | return 0; /* reject, with peercert set */ | |
e51c7be2 JH |
447 | #endif |
448 | ||
93dcb1c2 | 449 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
f69979cf | 450 | *calledp ? "" : " authenticated", dn); |
93dcb1c2 JH |
451 | if (!*calledp) tlsp->certificate_verified = TRUE; |
452 | *calledp = TRUE; | |
059ec3d9 PH |
453 | } |
454 | ||
a7538db1 | 455 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
456 | } |
457 | ||
a2ff477a JH |
458 | static int |
459 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
460 | { | |
f5d78688 | 461 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); |
a2ff477a JH |
462 | } |
463 | ||
464 | static int | |
465 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
466 | { | |
f5d78688 | 467 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); |
a2ff477a JH |
468 | } |
469 | ||
059ec3d9 | 470 | |
e5cccda9 | 471 | #ifdef EXPERIMENTAL_DANE |
53a7196b | 472 | |
e5cccda9 JH |
473 | /* This gets called *by* the dane library verify callback, which interposes |
474 | itself. | |
475 | */ | |
476 | static int | |
477 | verify_callback_client_dane(int state, X509_STORE_CTX * x509ctx) | |
478 | { | |
479 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
f69979cf | 480 | uschar dn[256]; |
774ef2d7 | 481 | #ifdef EXPERIMENTAL_EVENT |
83b27293 | 482 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 483 | BOOL dummy_called, optional = FALSE; |
83b27293 | 484 | #endif |
e5cccda9 | 485 | |
f69979cf JH |
486 | X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn)); |
487 | dn[sizeof(dn)-1] = '\0'; | |
e5cccda9 | 488 | |
f69979cf | 489 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", dn); |
e5cccda9 | 490 | |
774ef2d7 | 491 | #ifdef EXPERIMENTAL_EVENT |
f69979cf JH |
492 | if (verify_event(&tls_out, cert, depth, dn, |
493 | &dummy_called, &optional, US"DANE")) | |
494 | return 0; /* reject, with peercert set */ | |
83b27293 JH |
495 | #endif |
496 | ||
e5cccda9 | 497 | if (state == 1) |
53a7196b | 498 | tls_out.dane_verified = |
e5cccda9 JH |
499 | tls_out.certificate_verified = TRUE; |
500 | return 1; | |
501 | } | |
53a7196b JH |
502 | |
503 | #endif /*EXPERIMENTAL_DANE*/ | |
e5cccda9 | 504 | |
059ec3d9 PH |
505 | |
506 | /************************************************* | |
507 | * Information callback * | |
508 | *************************************************/ | |
509 | ||
510 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
511 | are doing. We copy the string to the debugging output when TLS debugging has |
512 | been requested. | |
059ec3d9 PH |
513 | |
514 | Arguments: | |
515 | s the SSL connection | |
516 | where | |
517 | ret | |
518 | ||
519 | Returns: nothing | |
520 | */ | |
521 | ||
522 | static void | |
523 | info_callback(SSL *s, int where, int ret) | |
524 | { | |
525 | where = where; | |
526 | ret = ret; | |
527 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
528 | } | |
529 | ||
530 | ||
531 | ||
532 | /************************************************* | |
533 | * Initialize for DH * | |
534 | *************************************************/ | |
535 | ||
536 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
537 | ||
538 | Arguments: | |
038597d2 | 539 | sctx The current SSL CTX (inbound or outbound) |
a799883d | 540 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 541 | host connected host, if client; NULL if server |
059ec3d9 PH |
542 | |
543 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
544 | */ | |
545 | ||
546 | static BOOL | |
b8b1b5cb | 547 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host) |
059ec3d9 | 548 | { |
059ec3d9 PH |
549 | BIO *bio; |
550 | DH *dh; | |
551 | uschar *dhexpanded; | |
a799883d | 552 | const char *pem; |
059ec3d9 PH |
553 | |
554 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
555 | return FALSE; | |
556 | ||
0df4ab80 | 557 | if (!dhexpanded || !*dhexpanded) |
a799883d | 558 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 559 | else if (dhexpanded[0] == '/') |
059ec3d9 | 560 | { |
0df4ab80 | 561 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 562 | { |
7199e1ee | 563 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
564 | host, US strerror(errno)); |
565 | return FALSE; | |
059ec3d9 | 566 | } |
a799883d PP |
567 | } |
568 | else | |
569 | { | |
570 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 571 | { |
a799883d PP |
572 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
573 | return TRUE; | |
059ec3d9 | 574 | } |
a799883d | 575 | |
0df4ab80 | 576 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
577 | { |
578 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
579 | host, US strerror(errno)); | |
580 | return FALSE; | |
581 | } | |
582 | bio = BIO_new_mem_buf(CS pem, -1); | |
583 | } | |
584 | ||
0df4ab80 | 585 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 586 | { |
059ec3d9 | 587 | BIO_free(bio); |
a799883d PP |
588 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
589 | host, NULL); | |
590 | return FALSE; | |
591 | } | |
592 | ||
593 | /* Even if it is larger, we silently return success rather than cause things | |
594 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
595 | * debatable choice. */ | |
596 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
597 | { | |
598 | DEBUG(D_tls) | |
599 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
600 | 8*DH_size(dh), tls_dh_max_bits); | |
601 | } | |
602 | else | |
603 | { | |
604 | SSL_CTX_set_tmp_dh(sctx, dh); | |
605 | DEBUG(D_tls) | |
606 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
607 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
608 | } |
609 | ||
a799883d PP |
610 | DH_free(dh); |
611 | BIO_free(bio); | |
612 | ||
613 | return TRUE; | |
059ec3d9 PH |
614 | } |
615 | ||
616 | ||
617 | ||
618 | ||
038597d2 PP |
619 | /************************************************* |
620 | * Initialize for ECDH * | |
621 | *************************************************/ | |
622 | ||
623 | /* Load parameters for ECDH encryption. | |
624 | ||
625 | For now, we stick to NIST P-256 because: it's simple and easy to configure; | |
626 | it avoids any patent issues that might bite redistributors; despite events in | |
627 | the news and concerns over curve choices, we're not cryptographers, we're not | |
628 | pretending to be, and this is "good enough" to be better than no support, | |
629 | protecting against most adversaries. Given another year or two, there might | |
630 | be sufficient clarity about a "right" way forward to let us make an informed | |
631 | decision, instead of a knee-jerk reaction. | |
632 | ||
633 | Longer-term, we should look at supporting both various named curves and | |
634 | external files generated with "openssl ecparam", much as we do for init_dh(). | |
635 | We should also support "none" as a value, to explicitly avoid initialisation. | |
636 | ||
637 | Patches welcome. | |
638 | ||
639 | Arguments: | |
640 | sctx The current SSL CTX (inbound or outbound) | |
641 | host connected host, if client; NULL if server | |
642 | ||
643 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
644 | */ | |
645 | ||
646 | static BOOL | |
647 | init_ecdh(SSL_CTX *sctx, host_item *host) | |
648 | { | |
649 | if (host) /* No ECDH setup for clients, only for servers */ | |
650 | return TRUE; | |
651 | ||
652 | #ifndef SSL_CTX_set_tmp_ecdh | |
653 | /* No elliptic curve API in OpenSSL, skip it */ | |
654 | DEBUG(D_tls) | |
655 | debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); | |
656 | return TRUE; | |
657 | #else | |
658 | # ifndef NID_X9_62_prime256v1 | |
659 | /* For now, stick to NIST P-256 to get "something" running. | |
660 | If that's not available, bail */ | |
661 | DEBUG(D_tls) | |
662 | debug_printf("NIST P-256 EC curve not available, skipping ECDH setup\n"); | |
663 | return TRUE; | |
664 | # else | |
665 | { | |
666 | EC_KEY * ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1); | |
667 | BOOL rv; | |
668 | ||
669 | /* The "tmp" in the name here refers to setting a tempoary key | |
670 | not to the stability of the interface. */ | |
671 | ||
672 | if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) != 0)) | |
673 | { | |
674 | DEBUG(D_tls) debug_printf("ECDH: enable NIST P-256 curve\n"); | |
675 | } | |
676 | else | |
677 | tls_error(US"Error enabling NIST P-256 curve", host, NULL); | |
678 | EC_KEY_free(ecdh); | |
679 | return rv; | |
680 | } | |
681 | # endif | |
682 | #endif | |
683 | } | |
684 | ||
685 | ||
686 | ||
687 | ||
f2de3a33 | 688 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
689 | /************************************************* |
690 | * Load OCSP information into state * | |
691 | *************************************************/ | |
692 | ||
f5d78688 | 693 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
694 | caller has determined this is needed. Checks validity. Debugs a message |
695 | if invalid. | |
696 | ||
697 | ASSUMES: single response, for single cert. | |
698 | ||
699 | Arguments: | |
700 | sctx the SSL_CTX* to update | |
701 | cbinfo various parts of session state | |
702 | expanded the filename putatively holding an OCSP response | |
703 | ||
704 | */ | |
705 | ||
706 | static void | |
f5d78688 | 707 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 PP |
708 | { |
709 | BIO *bio; | |
710 | OCSP_RESPONSE *resp; | |
711 | OCSP_BASICRESP *basic_response; | |
712 | OCSP_SINGLERESP *single_response; | |
713 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
714 | X509_STORE *store; | |
715 | unsigned long verify_flags; | |
716 | int status, reason, i; | |
717 | ||
f5d78688 JH |
718 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
719 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 720 | { |
f5d78688 JH |
721 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
722 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
723 | } |
724 | ||
f5d78688 | 725 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); |
3f7eeb86 PP |
726 | if (!bio) |
727 | { | |
728 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 729 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
730 | return; |
731 | } | |
732 | ||
733 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
734 | BIO_free(bio); | |
735 | if (!resp) | |
736 | { | |
737 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
738 | return; | |
739 | } | |
740 | ||
741 | status = OCSP_response_status(resp); | |
742 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
743 | { | |
744 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
745 | OCSP_response_status_str(status), status); | |
f5d78688 | 746 | goto bad; |
3f7eeb86 PP |
747 | } |
748 | ||
749 | basic_response = OCSP_response_get1_basic(resp); | |
750 | if (!basic_response) | |
751 | { | |
752 | DEBUG(D_tls) | |
753 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 754 | goto bad; |
3f7eeb86 PP |
755 | } |
756 | ||
757 | store = SSL_CTX_get_cert_store(sctx); | |
758 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
759 | ||
760 | /* May need to expose ability to adjust those flags? | |
761 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
762 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
763 | ||
764 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
765 | if (i <= 0) | |
766 | { | |
767 | DEBUG(D_tls) { | |
768 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
769 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
770 | } |
771 | goto bad; | |
3f7eeb86 PP |
772 | } |
773 | ||
774 | /* Here's the simplifying assumption: there's only one response, for the | |
775 | one certificate we use, and nothing for anything else in a chain. If this | |
776 | proves false, we need to extract a cert id from our issued cert | |
777 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
778 | right cert in the stack and then calls OCSP_single_get0_status()). | |
779 | ||
780 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
781 | single_response = OCSP_resp_get0(basic_response, 0); | |
782 | if (!single_response) | |
783 | { | |
784 | DEBUG(D_tls) | |
785 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 786 | goto bad; |
3f7eeb86 PP |
787 | } |
788 | ||
789 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 790 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 791 | { |
f5d78688 JH |
792 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
793 | OCSP_cert_status_str(status), status, | |
794 | OCSP_crl_reason_str(reason), reason); | |
795 | goto bad; | |
3f7eeb86 PP |
796 | } |
797 | ||
798 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
799 | { | |
800 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 801 | goto bad; |
3f7eeb86 PP |
802 | } |
803 | ||
f5d78688 | 804 | supply_response: |
018058b2 | 805 | cbinfo->u_ocsp.server.response = resp; |
f5d78688 JH |
806 | return; |
807 | ||
808 | bad: | |
018058b2 JH |
809 | if (running_in_test_harness) |
810 | { | |
811 | extern char ** environ; | |
812 | uschar ** p; | |
813 | for (p = USS environ; *p != NULL; p++) | |
814 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
815 | { | |
816 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
817 | goto supply_response; | |
818 | } | |
819 | } | |
f5d78688 | 820 | return; |
3f7eeb86 | 821 | } |
f2de3a33 | 822 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
823 | |
824 | ||
825 | ||
826 | ||
7be682ca PP |
827 | /************************************************* |
828 | * Expand key and cert file specs * | |
829 | *************************************************/ | |
830 | ||
f5d78688 | 831 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
832 | new context, if Server Name Indication was used and tls_sni was seen in |
833 | the certificate string. | |
834 | ||
835 | Arguments: | |
836 | sctx the SSL_CTX* to update | |
837 | cbinfo various parts of session state | |
838 | ||
839 | Returns: OK/DEFER/FAIL | |
840 | */ | |
841 | ||
842 | static int | |
3f7eeb86 | 843 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
844 | { |
845 | uschar *expanded; | |
846 | ||
847 | if (cbinfo->certificate == NULL) | |
848 | return OK; | |
849 | ||
d9b2312b JH |
850 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
851 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
852 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
853 | ) | |
7be682ca PP |
854 | reexpand_tls_files_for_sni = TRUE; |
855 | ||
856 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
857 | return DEFER; | |
858 | ||
859 | if (expanded != NULL) | |
860 | { | |
861 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
862 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
863 | return tls_error(string_sprintf( | |
864 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
865 | cbinfo->host, NULL); | |
866 | } | |
867 | ||
868 | if (cbinfo->privatekey != NULL && | |
869 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
870 | return DEFER; | |
871 | ||
872 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
873 | of the expansion is an empty string, ignore it also, and assume the private | |
874 | key is in the same file as the certificate. */ | |
875 | ||
876 | if (expanded != NULL && *expanded != 0) | |
877 | { | |
878 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
879 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
880 | return tls_error(string_sprintf( | |
881 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
882 | } | |
883 | ||
f2de3a33 | 884 | #ifndef DISABLE_OCSP |
f5d78688 | 885 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) |
3f7eeb86 | 886 | { |
f5d78688 | 887 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) |
3f7eeb86 PP |
888 | return DEFER; |
889 | ||
890 | if (expanded != NULL && *expanded != 0) | |
891 | { | |
892 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f5d78688 JH |
893 | if (cbinfo->u_ocsp.server.file_expanded && |
894 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 PP |
895 | { |
896 | DEBUG(D_tls) | |
897 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
898 | } else { | |
899 | ocsp_load_response(sctx, cbinfo, expanded); | |
900 | } | |
901 | } | |
902 | } | |
903 | #endif | |
904 | ||
7be682ca PP |
905 | return OK; |
906 | } | |
907 | ||
908 | ||
909 | ||
910 | ||
911 | /************************************************* | |
912 | * Callback to handle SNI * | |
913 | *************************************************/ | |
914 | ||
915 | /* Called when acting as server during the TLS session setup if a Server Name | |
916 | Indication extension was sent by the client. | |
917 | ||
918 | API documentation is OpenSSL s_server.c implementation. | |
919 | ||
920 | Arguments: | |
921 | s SSL* of the current session | |
922 | ad unknown (part of OpenSSL API) (unused) | |
923 | arg Callback of "our" registered data | |
924 | ||
925 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
926 | */ | |
927 | ||
3bcbbbe2 | 928 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
929 | static int |
930 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
931 | { | |
932 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 933 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 934 | int rc; |
3f0945ff | 935 | int old_pool = store_pool; |
7be682ca PP |
936 | |
937 | if (!servername) | |
938 | return SSL_TLSEXT_ERR_OK; | |
939 | ||
3f0945ff | 940 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
941 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
942 | ||
943 | /* Make the extension value available for expansion */ | |
3f0945ff | 944 | store_pool = POOL_PERM; |
817d9f57 | 945 | tls_in.sni = string_copy(US servername); |
3f0945ff | 946 | store_pool = old_pool; |
7be682ca PP |
947 | |
948 | if (!reexpand_tls_files_for_sni) | |
949 | return SSL_TLSEXT_ERR_OK; | |
950 | ||
951 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
952 | not confident that memcpy wouldn't break some internal reference counting. | |
953 | Especially since there's a references struct member, which would be off. */ | |
954 | ||
0df4ab80 | 955 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7be682ca PP |
956 | { |
957 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
958 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
959 | return SSL_TLSEXT_ERR_NOACK; | |
960 | } | |
961 | ||
962 | /* Not sure how many of these are actually needed, since SSL object | |
963 | already exists. Might even need this selfsame callback, for reneg? */ | |
964 | ||
817d9f57 JH |
965 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
966 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
967 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
968 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
969 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
970 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
038597d2 PP |
971 | |
972 | if ( !init_dh(server_sni, cbinfo->dhparam, NULL) | |
973 | || !init_ecdh(server_sni, NULL) | |
974 | ) | |
975 | return SSL_TLSEXT_ERR_NOACK; | |
976 | ||
7be682ca | 977 | if (cbinfo->server_cipher_list) |
817d9f57 | 978 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
f2de3a33 | 979 | #ifndef DISABLE_OCSP |
f5d78688 | 980 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 981 | { |
f5d78688 | 982 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 983 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
984 | } |
985 | #endif | |
7be682ca | 986 | |
983207c1 | 987 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server); |
7be682ca PP |
988 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
989 | ||
3f7eeb86 PP |
990 | /* do this after setup_certs, because this can require the certs for verifying |
991 | OCSP information. */ | |
038597d2 | 992 | if ((rc = tls_expand_session_files(server_sni, cbinfo)) != OK) |
0df4ab80 | 993 | return SSL_TLSEXT_ERR_NOACK; |
a799883d | 994 | |
7be682ca | 995 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 996 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
997 | |
998 | return SSL_TLSEXT_ERR_OK; | |
999 | } | |
3bcbbbe2 | 1000 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
1001 | |
1002 | ||
1003 | ||
1004 | ||
f2de3a33 | 1005 | #ifndef DISABLE_OCSP |
f5d78688 | 1006 | |
3f7eeb86 PP |
1007 | /************************************************* |
1008 | * Callback to handle OCSP Stapling * | |
1009 | *************************************************/ | |
1010 | ||
1011 | /* Called when acting as server during the TLS session setup if the client | |
1012 | requests OCSP information with a Certificate Status Request. | |
1013 | ||
1014 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
1015 | project. | |
1016 | ||
1017 | */ | |
1018 | ||
1019 | static int | |
f5d78688 | 1020 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
1021 | { |
1022 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
1023 | uschar *response_der; | |
1024 | int response_der_len; | |
1025 | ||
af4a1bca | 1026 | DEBUG(D_tls) |
b3ef41c9 | 1027 | debug_printf("Received TLS status request (OCSP stapling); %s response\n", |
f5d78688 JH |
1028 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
1029 | ||
44662487 | 1030 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 1031 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
1032 | return SSL_TLSEXT_ERR_NOACK; |
1033 | ||
1034 | response_der = NULL; | |
44662487 JH |
1035 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, |
1036 | &response_der); | |
3f7eeb86 PP |
1037 | if (response_der_len <= 0) |
1038 | return SSL_TLSEXT_ERR_NOACK; | |
1039 | ||
5e55c7a9 | 1040 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 1041 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
1042 | return SSL_TLSEXT_ERR_OK; |
1043 | } | |
1044 | ||
3f7eeb86 | 1045 | |
f5d78688 JH |
1046 | static void |
1047 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
1048 | { | |
1049 | BIO_printf(bp, "\t%s: ", str); | |
1050 | ASN1_GENERALIZEDTIME_print(bp, time); | |
1051 | BIO_puts(bp, "\n"); | |
1052 | } | |
1053 | ||
1054 | static int | |
1055 | tls_client_stapling_cb(SSL *s, void *arg) | |
1056 | { | |
1057 | tls_ext_ctx_cb * cbinfo = arg; | |
1058 | const unsigned char * p; | |
1059 | int len; | |
1060 | OCSP_RESPONSE * rsp; | |
1061 | OCSP_BASICRESP * bs; | |
1062 | int i; | |
1063 | ||
1064 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
1065 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
1066 | if(!p) | |
1067 | { | |
44662487 JH |
1068 | /* Expect this when we requested ocsp but got none */ |
1069 | if ( cbinfo->u_ocsp.client.verify_required | |
1070 | && log_extra_selector & LX_tls_cipher) | |
1071 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); | |
f5d78688 JH |
1072 | else |
1073 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1074 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1075 | } |
018058b2 | 1076 | |
f5d78688 JH |
1077 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
1078 | { | |
018058b2 | 1079 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 | 1080 | if (log_extra_selector & LX_tls_cipher) |
1eca31ca | 1081 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
1082 | else |
1083 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1084 | return 0; | |
1085 | } | |
1086 | ||
1087 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
1088 | { | |
018058b2 | 1089 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 | 1090 | if (log_extra_selector & LX_tls_cipher) |
1eca31ca | 1091 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1092 | else |
1093 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1094 | OCSP_RESPONSE_free(rsp); | |
1095 | return 0; | |
1096 | } | |
1097 | ||
1098 | /* We'd check the nonce here if we'd put one in the request. */ | |
1099 | /* However that would defeat cacheability on the server so we don't. */ | |
1100 | ||
f5d78688 JH |
1101 | /* This section of code reworked from OpenSSL apps source; |
1102 | The OpenSSL Project retains copyright: | |
1103 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1104 | */ | |
1105 | { | |
1106 | BIO * bp = NULL; | |
f5d78688 JH |
1107 | int status, reason; |
1108 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1109 | ||
1110 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
1111 | ||
1112 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1113 | ||
1114 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1115 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1116 | ||
44662487 JH |
1117 | if ((i = OCSP_basic_verify(bs, NULL, |
1118 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
f5d78688 | 1119 | { |
018058b2 | 1120 | tls_out.ocsp = OCSP_FAILED; |
1eca31ca JH |
1121 | if (log_extra_selector & LX_tls_cipher) |
1122 | log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable"); | |
f5d78688 JH |
1123 | BIO_printf(bp, "OCSP response verify failure\n"); |
1124 | ERR_print_errors(bp); | |
44662487 | 1125 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 JH |
1126 | goto out; |
1127 | } | |
1128 | ||
1129 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1130 | ||
1131 | { | |
1132 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
1133 | OCSP_SINGLERESP * single; | |
1134 | ||
1135 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
1136 | { | |
018058b2 | 1137 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1138 | log_write(0, LOG_MAIN, "OCSP stapling " |
1139 | "with multiple responses not handled"); | |
1140 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
f5d78688 JH |
1141 | goto out; |
1142 | } | |
1143 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1144 | status = OCSP_single_get0_status(single, &reason, &rev, |
1145 | &thisupd, &nextupd); | |
f5d78688 JH |
1146 | } |
1147 | ||
f5d78688 JH |
1148 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1149 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1150 | if (!OCSP_check_validity(thisupd, nextupd, |
1151 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1152 | { |
018058b2 | 1153 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1154 | DEBUG(D_tls) ERR_print_errors(bp); |
1155 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
44662487 | 1156 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1157 | } |
44662487 | 1158 | else |
f5d78688 | 1159 | { |
44662487 JH |
1160 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1161 | OCSP_cert_status_str(status)); | |
1162 | switch(status) | |
1163 | { | |
1164 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1165 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1166 | i = 1; |
44662487 JH |
1167 | break; |
1168 | case V_OCSP_CERTSTATUS_REVOKED: | |
018058b2 | 1169 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1170 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1171 | reason != -1 ? "; reason: " : "", | |
1172 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1173 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
1174 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1175 | break; | |
1176 | default: | |
018058b2 | 1177 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1178 | log_write(0, LOG_MAIN, |
1179 | "Server certificate status unknown, in OCSP stapling"); | |
1180 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1181 | break; | |
1182 | } | |
f5d78688 JH |
1183 | } |
1184 | out: | |
1185 | BIO_free(bp); | |
1186 | } | |
1187 | ||
1188 | OCSP_RESPONSE_free(rsp); | |
1189 | return i; | |
1190 | } | |
f2de3a33 | 1191 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1192 | |
1193 | ||
059ec3d9 PH |
1194 | /************************************************* |
1195 | * Initialize for TLS * | |
1196 | *************************************************/ | |
1197 | ||
e51c7be2 JH |
1198 | /* Called from both server and client code, to do preliminary initialization |
1199 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1200 | |
1201 | Arguments: | |
946ecbe0 | 1202 | ctxp returned SSL context |
059ec3d9 PH |
1203 | host connected host, if client; NULL if server |
1204 | dhparam DH parameter file | |
1205 | certificate certificate file | |
1206 | privatekey private key | |
f5d78688 | 1207 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1208 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1209 | cbp place to put allocated callback context |
059ec3d9 PH |
1210 | |
1211 | Returns: OK/DEFER/FAIL | |
1212 | */ | |
1213 | ||
1214 | static int | |
817d9f57 | 1215 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1216 | uschar *privatekey, |
f2de3a33 | 1217 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1218 | uschar *ocsp_file, |
1219 | #endif | |
817d9f57 | 1220 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 1221 | { |
77bb000f | 1222 | long init_options; |
7be682ca | 1223 | int rc; |
77bb000f | 1224 | BOOL okay; |
a7538db1 | 1225 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1226 | |
1227 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1228 | cbinfo->certificate = certificate; | |
1229 | cbinfo->privatekey = privatekey; | |
f2de3a33 | 1230 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1231 | if ((cbinfo->is_server = host==NULL)) |
1232 | { | |
1233 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1234 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1235 | cbinfo->u_ocsp.server.response = NULL; | |
1236 | } | |
1237 | else | |
1238 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1239 | #endif |
7be682ca | 1240 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1241 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1242 | cbinfo->host = host; |
774ef2d7 | 1243 | #ifdef EXPERIMENTAL_EVENT |
a7538db1 JH |
1244 | cbinfo->event_action = NULL; |
1245 | #endif | |
77bb000f | 1246 | |
059ec3d9 PH |
1247 | SSL_load_error_strings(); /* basic set up */ |
1248 | OpenSSL_add_ssl_algorithms(); | |
1249 | ||
388d6564 | 1250 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 1251 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1252 | list of available digests. */ |
1253 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1254 | #endif |
a0475b69 | 1255 | |
f0f5a555 PP |
1256 | /* Create a context. |
1257 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1258 | negotiation in the different methods; as far as I can tell, the only | |
1259 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1260 | when OpenSSL is built without SSLv2 support. | |
1261 | By disabling with openssl_options, we can let admins re-enable with the | |
1262 | existing knob. */ | |
059ec3d9 | 1263 | |
817d9f57 | 1264 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
1265 | SSLv23_server_method() : SSLv23_client_method()); |
1266 | ||
817d9f57 | 1267 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
1268 | |
1269 | /* It turns out that we need to seed the random number generator this early in | |
1270 | order to get the full complement of ciphers to work. It took me roughly a day | |
1271 | of work to discover this by experiment. | |
1272 | ||
1273 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1274 | there. Otherwise, we have to make something up as best we can. Double check | |
1275 | afterwards. */ | |
1276 | ||
1277 | if (!RAND_status()) | |
1278 | { | |
1279 | randstuff r; | |
9e3331ea | 1280 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1281 | r.p = getpid(); |
1282 | ||
1283 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1284 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1285 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1286 | ||
1287 | if (!RAND_status()) | |
7199e1ee | 1288 | return tls_error(US"RAND_status", host, |
5ca6d115 | 1289 | US"unable to seed random number generator"); |
059ec3d9 PH |
1290 | } |
1291 | ||
1292 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1293 | level. */ | |
1294 | ||
f69979cf | 1295 | DEBUG(D_tls) SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 1296 | |
c80c5570 | 1297 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 1298 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1299 | |
77bb000f PP |
1300 | /* Apply administrator-supplied work-arounds. |
1301 | Historically we applied just one requested option, | |
1302 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1303 | moved to an administrator-controlled list of options to specify and | |
1304 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1305 | |
77bb000f PP |
1306 | No OpenSSL version number checks: the options we accept depend upon the |
1307 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1308 | |
77bb000f PP |
1309 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
1310 | if (!okay) | |
73a46702 | 1311 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
1312 | |
1313 | if (init_options) | |
1314 | { | |
1315 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 1316 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
1317 | return tls_error(string_sprintf( |
1318 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1319 | } | |
1320 | else | |
1321 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
1322 | |
1323 | /* Initialize with DH parameters if supplied */ | |
1324 | ||
038597d2 PP |
1325 | if ( !init_dh(*ctxp, dhparam, host) |
1326 | || !init_ecdh(*ctxp, host) | |
1327 | ) | |
1328 | return DEFER; | |
059ec3d9 | 1329 | |
3f7eeb86 | 1330 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1331 | |
817d9f57 | 1332 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 1333 | if (rc != OK) return rc; |
c91535f3 | 1334 | |
7be682ca | 1335 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 1336 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
f5d78688 | 1337 | if (host == NULL) /* server */ |
3f0945ff | 1338 | { |
f2de3a33 | 1339 | # ifndef DISABLE_OCSP |
f5d78688 | 1340 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1341 | the option exists, not what the current expansion might be, as SNI might |
1342 | change the certificate and OCSP file in use between now and the time the | |
1343 | callback is invoked. */ | |
f5d78688 | 1344 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1345 | { |
f5d78688 | 1346 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); |
5e55c7a9 | 1347 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); |
3f7eeb86 | 1348 | } |
f5d78688 | 1349 | # endif |
3f0945ff PP |
1350 | /* We always do this, so that $tls_sni is available even if not used in |
1351 | tls_certificate */ | |
817d9f57 JH |
1352 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
1353 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 1354 | } |
f2de3a33 | 1355 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1356 | else /* client */ |
1357 | if(ocsp_file) /* wanting stapling */ | |
1358 | { | |
1359 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1360 | { | |
1361 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1362 | return FAIL; | |
1363 | } | |
1364 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1365 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1366 | } | |
1367 | # endif | |
7be682ca | 1368 | #endif |
059ec3d9 | 1369 | |
e51c7be2 | 1370 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 1371 | |
059ec3d9 PH |
1372 | /* Set up the RSA callback */ |
1373 | ||
817d9f57 | 1374 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
1375 | |
1376 | /* Finally, set the timeout, and we are done */ | |
1377 | ||
817d9f57 | 1378 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 1379 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1380 | |
817d9f57 | 1381 | *cbp = cbinfo; |
7be682ca | 1382 | |
059ec3d9 PH |
1383 | return OK; |
1384 | } | |
1385 | ||
1386 | ||
1387 | ||
1388 | ||
1389 | /************************************************* | |
1390 | * Get name of cipher in use * | |
1391 | *************************************************/ | |
1392 | ||
817d9f57 | 1393 | /* |
059ec3d9 | 1394 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1395 | buffer to use for answer |
1396 | size of buffer | |
1397 | pointer to number of bits for cipher | |
059ec3d9 PH |
1398 | Returns: nothing |
1399 | */ | |
1400 | ||
1401 | static void | |
817d9f57 | 1402 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1403 | { |
57b3a7f5 PP |
1404 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1405 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1406 | the accessor functions use const in the prototype. */ | |
1407 | const SSL_CIPHER *c; | |
d9784128 | 1408 | const uschar *ver; |
059ec3d9 | 1409 | |
d9784128 | 1410 | ver = (const uschar *)SSL_get_version(ssl); |
059ec3d9 | 1411 | |
57b3a7f5 | 1412 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1413 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1414 | |
817d9f57 JH |
1415 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1416 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1417 | |
1418 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1419 | } | |
1420 | ||
1421 | ||
f69979cf JH |
1422 | static void |
1423 | peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned bsize) | |
1424 | { | |
1425 | /*XXX we might consider a list-of-certs variable for the cert chain. | |
1426 | SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support | |
1427 | in list-handling functions, also consider the difference between the entire | |
1428 | chain and the elements sent by the peer. */ | |
1429 | ||
1430 | /* Will have already noted peercert on a verify fail; possibly not the leaf */ | |
1431 | if (!tlsp->peercert) | |
1432 | tlsp->peercert = SSL_get_peer_certificate(ssl); | |
1433 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
1434 | if (tlsp->peercert) | |
1435 | { | |
1436 | X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, bsize); | |
1437 | peerdn[bsize-1] = '\0'; | |
1438 | tlsp->peerdn = peerdn; /*XXX a static buffer... */ | |
1439 | } | |
1440 | else | |
1441 | tlsp->peerdn = NULL; | |
1442 | } | |
1443 | ||
1444 | ||
059ec3d9 PH |
1445 | |
1446 | ||
1447 | ||
1448 | /************************************************* | |
1449 | * Set up for verifying certificates * | |
1450 | *************************************************/ | |
1451 | ||
1452 | /* Called by both client and server startup | |
1453 | ||
1454 | Arguments: | |
7be682ca | 1455 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1456 | certs certs file or NULL |
1457 | crl CRL file or NULL | |
1458 | host NULL in a server; the remote host in a client | |
1459 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1460 | otherwise passed as FALSE | |
983207c1 | 1461 | cert_vfy_cb Callback function for certificate verification |
059ec3d9 PH |
1462 | |
1463 | Returns: OK/DEFER/FAIL | |
1464 | */ | |
1465 | ||
1466 | static int | |
983207c1 JH |
1467 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
1468 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ) | |
059ec3d9 PH |
1469 | { |
1470 | uschar *expcerts, *expcrl; | |
1471 | ||
1472 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1473 | return DEFER; | |
1474 | ||
26e72755 | 1475 | if (expcerts != NULL && *expcerts != '\0') |
059ec3d9 | 1476 | { |
cb1d7830 | 1477 | if (Ustrcmp(expcerts, "system") == 0) |
059ec3d9 | 1478 | { |
cb1d7830 JH |
1479 | /* Tell the library to use its compiled-in location for the system default |
1480 | CA bundle, only */ | |
1481 | ||
1482 | if (!SSL_CTX_set_default_verify_paths(sctx)) | |
1483 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); | |
059ec3d9 PH |
1484 | } |
1485 | else | |
1486 | { | |
cb1d7830 JH |
1487 | struct stat statbuf; |
1488 | ||
1489 | /* Tell the library to use its compiled-in location for the system default | |
1490 | CA bundle. Those given by the exim config are additional to these */ | |
1491 | ||
1492 | if (!SSL_CTX_set_default_verify_paths(sctx)) | |
1493 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); | |
1494 | ||
1495 | if (Ustat(expcerts, &statbuf) < 0) | |
1496 | { | |
1497 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1498 | "failed to stat %s for certificates", expcerts); | |
1499 | return DEFER; | |
1500 | } | |
059ec3d9 | 1501 | else |
059ec3d9 | 1502 | { |
cb1d7830 JH |
1503 | uschar *file, *dir; |
1504 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1505 | { file = NULL; dir = expcerts; } | |
1506 | else | |
1507 | { file = expcerts; dir = NULL; } | |
1508 | ||
1509 | /* If a certificate file is empty, the next function fails with an | |
1510 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1511 | certificates are recognized, but the error message is still misleading (it | |
1512 | says no certificate was supplied.) But this is better. */ | |
1513 | ||
1514 | if ((file == NULL || statbuf.st_size > 0) && | |
1515 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
1516 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); | |
1517 | ||
1518 | /* Load the list of CAs for which we will accept certs, for sending | |
1519 | to the client. This is only for the one-file tls_verify_certificates | |
1520 | variant. | |
1521 | If a list isn't loaded into the server, but | |
1522 | some verify locations are set, the server end appears to make | |
1523 | a wildcard reqest for client certs. | |
1524 | Meanwhile, the client library as deafult behaviour *ignores* the list | |
1525 | we send over the wire - see man SSL_CTX_set_client_cert_cb. | |
1526 | Because of this, and that the dir variant is likely only used for | |
1527 | the public-CA bundle (not for a private CA), not worth fixing. | |
1528 | */ | |
1529 | if (file != NULL) | |
1530 | { | |
1531 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); | |
1532 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", | |
1533 | sk_X509_NAME_num(names)); | |
1534 | SSL_CTX_set_client_CA_list(sctx, names); | |
1535 | } | |
059ec3d9 PH |
1536 | } |
1537 | } | |
1538 | ||
1539 | /* Handle a certificate revocation list. */ | |
1540 | ||
1541 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1542 | ||
8b417f2c PH |
1543 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1544 | * merely reformatted it into the Exim code style.) | |
1545 | ||
1546 | * "From here I changed the code to add support for multiple crl's | |
1547 | * in pem format in one file or to support hashed directory entries in | |
1548 | * pem format instead of a file. This method now uses the library function | |
1549 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1550 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1551 | * itself in the verify callback." */ | |
1552 | ||
059ec3d9 PH |
1553 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1554 | if (expcrl != NULL && *expcrl != 0) | |
1555 | { | |
8b417f2c PH |
1556 | struct stat statbufcrl; |
1557 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1558 | { | |
1559 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1560 | "failed to stat %s for certificates revocation lists", expcrl); | |
1561 | return DEFER; | |
1562 | } | |
1563 | else | |
059ec3d9 | 1564 | { |
8b417f2c PH |
1565 | /* is it a file or directory? */ |
1566 | uschar *file, *dir; | |
7be682ca | 1567 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1568 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1569 | { |
8b417f2c PH |
1570 | file = NULL; |
1571 | dir = expcrl; | |
1572 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1573 | } |
1574 | else | |
1575 | { | |
8b417f2c PH |
1576 | file = expcrl; |
1577 | dir = NULL; | |
1578 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1579 | } |
8b417f2c | 1580 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1581 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1582 | |
1583 | /* setting the flags to check against the complete crl chain */ | |
1584 | ||
1585 | X509_STORE_set_flags(cvstore, | |
1586 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1587 | } |
059ec3d9 PH |
1588 | } |
1589 | ||
1590 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1591 | ||
1592 | /* If verification is optional, don't fail if no certificate */ | |
1593 | ||
7be682ca | 1594 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1595 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 1596 | cert_vfy_cb); |
059ec3d9 PH |
1597 | } |
1598 | ||
1599 | return OK; | |
1600 | } | |
1601 | ||
1602 | ||
1603 | ||
1604 | /************************************************* | |
1605 | * Start a TLS session in a server * | |
1606 | *************************************************/ | |
1607 | ||
1608 | /* This is called when Exim is running as a server, after having received | |
1609 | the STARTTLS command. It must respond to that command, and then negotiate | |
1610 | a TLS session. | |
1611 | ||
1612 | Arguments: | |
1613 | require_ciphers allowed ciphers | |
1614 | ||
1615 | Returns: OK on success | |
1616 | DEFER for errors before the start of the negotiation | |
1617 | FAIL for errors during the negotation; the server can't | |
1618 | continue running. | |
1619 | */ | |
1620 | ||
1621 | int | |
17c76198 | 1622 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1623 | { |
1624 | int rc; | |
1625 | uschar *expciphers; | |
7be682ca | 1626 | tls_ext_ctx_cb *cbinfo; |
f69979cf | 1627 | static uschar peerdn[256]; |
817d9f57 | 1628 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1629 | |
1630 | /* Check for previous activation */ | |
1631 | ||
817d9f57 | 1632 | if (tls_in.active >= 0) |
059ec3d9 | 1633 | { |
5ca6d115 | 1634 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1635 | smtp_printf("554 Already in TLS\r\n"); |
1636 | return FAIL; | |
1637 | } | |
1638 | ||
1639 | /* Initialize the SSL library. If it fails, it will already have logged | |
1640 | the error. */ | |
1641 | ||
817d9f57 | 1642 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 1643 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1644 | tls_ocsp_file, |
1645 | #endif | |
817d9f57 | 1646 | NULL, &server_static_cbinfo); |
059ec3d9 | 1647 | if (rc != OK) return rc; |
817d9f57 | 1648 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1649 | |
1650 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1651 | return FAIL; | |
1652 | ||
1653 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1654 | were historically separated by underscores. So that I can use either form in my |
1655 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1656 | */ | |
059ec3d9 PH |
1657 | |
1658 | if (expciphers != NULL) | |
1659 | { | |
1660 | uschar *s = expciphers; | |
1661 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1662 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1663 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1664 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1665 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1666 | } |
1667 | ||
1668 | /* If this is a host for which certificate verification is mandatory or | |
1669 | optional, set up appropriately. */ | |
1670 | ||
817d9f57 | 1671 | tls_in.certificate_verified = FALSE; |
53a7196b JH |
1672 | #ifdef EXPERIMENTAL_DANE |
1673 | tls_in.dane_verified = FALSE; | |
1674 | #endif | |
a2ff477a | 1675 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1676 | |
1677 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1678 | { | |
983207c1 JH |
1679 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1680 | FALSE, verify_callback_server); | |
059ec3d9 | 1681 | if (rc != OK) return rc; |
a2ff477a | 1682 | server_verify_optional = FALSE; |
059ec3d9 PH |
1683 | } |
1684 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1685 | { | |
983207c1 JH |
1686 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1687 | TRUE, verify_callback_server); | |
059ec3d9 | 1688 | if (rc != OK) return rc; |
a2ff477a | 1689 | server_verify_optional = TRUE; |
059ec3d9 PH |
1690 | } |
1691 | ||
1692 | /* Prepare for new connection */ | |
1693 | ||
817d9f57 | 1694 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1695 | |
1696 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1697 | * | |
1698 | * With the SSL_clear(), we get strange interoperability bugs with | |
1699 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1700 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1701 | * | |
1702 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1703 | * session shutdown. In this case, we have a brand new object and there's no | |
1704 | * obvious reason to immediately clear it. I'm guessing that this was | |
1705 | * originally added because of incomplete initialisation which the clear fixed, | |
1706 | * in some historic release. | |
1707 | */ | |
059ec3d9 PH |
1708 | |
1709 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1710 | on connection, where outputting anything now upsets the clients and tends to | |
1711 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1712 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1713 | mode, the fflush() happens when smtp_getc() is called. */ | |
1714 | ||
817d9f57 JH |
1715 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1716 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1717 | { |
1718 | smtp_printf("220 TLS go ahead\r\n"); | |
1719 | fflush(smtp_out); | |
1720 | } | |
1721 | ||
1722 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1723 | that the OpenSSL library doesn't. */ | |
1724 | ||
817d9f57 JH |
1725 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1726 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1727 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1728 | |
1729 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1730 | ||
1731 | sigalrm_seen = FALSE; | |
1732 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1733 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1734 | alarm(0); |
1735 | ||
1736 | if (rc <= 0) | |
1737 | { | |
7199e1ee | 1738 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1739 | if (ERR_get_error() == 0) |
1740 | log_write(0, LOG_MAIN, | |
a053d125 | 1741 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1742 | return FAIL; |
1743 | } | |
1744 | ||
1745 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1746 | ||
1747 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1748 | and initialize things. */ | |
1749 | ||
f69979cf JH |
1750 | peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn)); |
1751 | ||
817d9f57 JH |
1752 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1753 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1754 | |
1755 | DEBUG(D_tls) | |
1756 | { | |
1757 | uschar buf[2048]; | |
817d9f57 | 1758 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1759 | debug_printf("Shared ciphers: %s\n", buf); |
1760 | } | |
1761 | ||
9d1c15ef JH |
1762 | /* Record the certificate we presented */ |
1763 | { | |
1764 | X509 * crt = SSL_get_certificate(server_ssl); | |
1765 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
1766 | } | |
059ec3d9 | 1767 | |
817d9f57 JH |
1768 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1769 | Client-side (tls_out) reads (seem to?) go via | |
1770 | smtp_read_response()/ip_recv(). | |
1771 | Hence no need to duplicate for _in and _out. | |
1772 | */ | |
059ec3d9 PH |
1773 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1774 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1775 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1776 | ||
1777 | receive_getc = tls_getc; | |
1778 | receive_ungetc = tls_ungetc; | |
1779 | receive_feof = tls_feof; | |
1780 | receive_ferror = tls_ferror; | |
58eb016e | 1781 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1782 | |
817d9f57 | 1783 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1784 | return OK; |
1785 | } | |
1786 | ||
1787 | ||
1788 | ||
1789 | ||
043b1248 JH |
1790 | static int |
1791 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
01a4a5c5 | 1792 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo |
043b1248 JH |
1793 | ) |
1794 | { | |
1795 | int rc; | |
1796 | /* stick to the old behaviour for compatibility if tls_verify_certificates is | |
1797 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only | |
1798 | the specified host patterns if one of them is defined */ | |
1799 | ||
610ff438 JH |
1800 | if ( ( !ob->tls_verify_hosts |
1801 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
1802 | ) | |
5130845b | 1803 | || (verify_check_given_host(&ob->tls_verify_hosts, host) == OK) |
aa2a70ba | 1804 | ) |
043b1248 | 1805 | client_verify_optional = FALSE; |
5130845b | 1806 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
1807 | client_verify_optional = TRUE; |
1808 | else | |
1809 | return OK; | |
1810 | ||
1811 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
1812 | ob->tls_crl, host, client_verify_optional, verify_callback_client)) != OK) | |
1813 | return rc; | |
043b1248 | 1814 | |
5130845b | 1815 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 1816 | { |
4af0d74a JH |
1817 | cbinfo->verify_cert_hostnames = |
1818 | #ifdef EXPERIMENTAL_INTERNATIONAL | |
1819 | string_domain_utf8_to_alabel(host->name, NULL); | |
1820 | #else | |
1821 | host->name; | |
1822 | #endif | |
aa2a70ba JH |
1823 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", |
1824 | cbinfo->verify_cert_hostnames); | |
043b1248 | 1825 | } |
043b1248 JH |
1826 | return OK; |
1827 | } | |
059ec3d9 | 1828 | |
fde080a4 JH |
1829 | |
1830 | #ifdef EXPERIMENTAL_DANE | |
fde080a4 JH |
1831 | static int |
1832 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa) | |
1833 | { | |
1834 | dns_record * rr; | |
1835 | dns_scan dnss; | |
1836 | const char * hostnames[2] = { CS host->name, NULL }; | |
1837 | int found = 0; | |
1838 | ||
1839 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
1840 | return tls_error(US"hostnames load", host, NULL); | |
1841 | ||
1842 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); | |
1843 | rr; | |
1844 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
1845 | ) if (rr->type == T_TLSA) | |
1846 | { | |
1847 | uschar * p = rr->data; | |
1848 | uint8_t usage, selector, mtype; | |
1849 | const char * mdname; | |
1850 | ||
fde080a4 | 1851 | usage = *p++; |
133d2546 JH |
1852 | |
1853 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
1854 | if (usage != 2 && usage != 3) continue; | |
1855 | ||
fde080a4 JH |
1856 | selector = *p++; |
1857 | mtype = *p++; | |
1858 | ||
1859 | switch (mtype) | |
1860 | { | |
133d2546 JH |
1861 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
1862 | case 0: mdname = NULL; break; | |
1863 | case 1: mdname = "sha256"; break; | |
1864 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
1865 | } |
1866 | ||
133d2546 | 1867 | found++; |
fde080a4 JH |
1868 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
1869 | { | |
1870 | default: | |
1871 | case 0: /* action not taken */ | |
1872 | return tls_error(US"tlsa load", host, NULL); | |
1873 | case 1: break; | |
1874 | } | |
594706ea JH |
1875 | |
1876 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
1877 | } |
1878 | ||
1879 | if (found) | |
1880 | return OK; | |
1881 | ||
133d2546 | 1882 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 1883 | return DEFER; |
fde080a4 JH |
1884 | } |
1885 | #endif /*EXPERIMENTAL_DANE*/ | |
1886 | ||
1887 | ||
1888 | ||
059ec3d9 PH |
1889 | /************************************************* |
1890 | * Start a TLS session in a client * | |
1891 | *************************************************/ | |
1892 | ||
1893 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1894 | ||
1895 | Argument: | |
1896 | fd the fd of the connection | |
1897 | host connected host (for messages) | |
83da1223 | 1898 | addr the first address |
a7538db1 | 1899 | tb transport (always smtp) |
0e66b3b6 | 1900 | tlsa_dnsa tlsa lookup, if DANE, else null |
059ec3d9 PH |
1901 | |
1902 | Returns: OK on success | |
1903 | FAIL otherwise - note that tls_error() will not give DEFER | |
1904 | because this is not a server | |
1905 | */ | |
1906 | ||
1907 | int | |
f5d78688 | 1908 | tls_client_start(int fd, host_item *host, address_item *addr, |
0e66b3b6 JH |
1909 | transport_instance *tb |
1910 | #ifdef EXPERIMENTAL_DANE | |
1911 | , dns_answer * tlsa_dnsa | |
1912 | #endif | |
1913 | ) | |
059ec3d9 | 1914 | { |
a7538db1 JH |
1915 | smtp_transport_options_block * ob = |
1916 | (smtp_transport_options_block *)tb->options_block; | |
f69979cf | 1917 | static uschar peerdn[256]; |
868f5672 | 1918 | uschar * expciphers; |
059ec3d9 | 1919 | int rc; |
817d9f57 | 1920 | static uschar cipherbuf[256]; |
043b1248 JH |
1921 | |
1922 | #ifndef DISABLE_OCSP | |
043b1248 | 1923 | BOOL request_ocsp = FALSE; |
6634ac8d | 1924 | BOOL require_ocsp = FALSE; |
043b1248 | 1925 | #endif |
043b1248 JH |
1926 | |
1927 | #ifdef EXPERIMENTAL_DANE | |
594706ea | 1928 | tls_out.tlsa_usage = 0; |
043b1248 JH |
1929 | #endif |
1930 | ||
f2de3a33 | 1931 | #ifndef DISABLE_OCSP |
043b1248 | 1932 | { |
4f59c424 JH |
1933 | # ifdef EXPERIMENTAL_DANE |
1934 | if ( tlsa_dnsa | |
1935 | && ob->hosts_request_ocsp[0] == '*' | |
1936 | && ob->hosts_request_ocsp[1] == '\0' | |
1937 | ) | |
1938 | { | |
1939 | /* Unchanged from default. Use a safer one under DANE */ | |
1940 | request_ocsp = TRUE; | |
1941 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
1942 | " {= {4}{$tls_out_tlsa_usage}} } " | |
1943 | " {*}{}}"; | |
1944 | } | |
1945 | # endif | |
1946 | ||
5130845b JH |
1947 | if ((require_ocsp = |
1948 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK)) | |
fca41d5a JH |
1949 | request_ocsp = TRUE; |
1950 | else | |
fca41d5a | 1951 | # ifdef EXPERIMENTAL_DANE |
4f59c424 | 1952 | if (!request_ocsp) |
fca41d5a | 1953 | # endif |
5130845b JH |
1954 | request_ocsp = |
1955 | verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
043b1248 | 1956 | } |
f5d78688 | 1957 | #endif |
059ec3d9 | 1958 | |
65867078 JH |
1959 | rc = tls_init(&client_ctx, host, NULL, |
1960 | ob->tls_certificate, ob->tls_privatekey, | |
f2de3a33 | 1961 | #ifndef DISABLE_OCSP |
44662487 | 1962 | (void *)(long)request_ocsp, |
3f7eeb86 | 1963 | #endif |
817d9f57 | 1964 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1965 | if (rc != OK) return rc; |
1966 | ||
817d9f57 | 1967 | tls_out.certificate_verified = FALSE; |
a2ff477a | 1968 | client_verify_callback_called = FALSE; |
059ec3d9 | 1969 | |
65867078 JH |
1970 | if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", |
1971 | &expciphers)) | |
059ec3d9 PH |
1972 | return FAIL; |
1973 | ||
1974 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1975 | are separated by underscores. So that I can use either form in my tests, and | |
1976 | also for general convenience, we turn underscores into hyphens here. */ | |
1977 | ||
1978 | if (expciphers != NULL) | |
1979 | { | |
1980 | uschar *s = expciphers; | |
1981 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1982 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1983 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1984 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1985 | } |
1986 | ||
043b1248 | 1987 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 1988 | if (tlsa_dnsa) |
a63be306 | 1989 | { |
02af313d JH |
1990 | SSL_CTX_set_verify(client_ctx, |
1991 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, | |
1992 | verify_callback_client_dane); | |
e5cccda9 | 1993 | |
043b1248 | 1994 | if (!DANESSL_library_init()) |
b4161d10 | 1995 | return tls_error(US"library init", host, NULL); |
043b1248 | 1996 | if (DANESSL_CTX_init(client_ctx) <= 0) |
b4161d10 | 1997 | return tls_error(US"context init", host, NULL); |
043b1248 JH |
1998 | } |
1999 | else | |
e51c7be2 | 2000 | |
043b1248 JH |
2001 | #endif |
2002 | ||
01a4a5c5 JH |
2003 | if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob, client_static_cbinfo)) |
2004 | != OK) | |
65867078 | 2005 | return rc; |
059ec3d9 | 2006 | |
65867078 JH |
2007 | if ((client_ssl = SSL_new(client_ctx)) == NULL) |
2008 | return tls_error(US"SSL_new", host, NULL); | |
817d9f57 JH |
2009 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); |
2010 | SSL_set_fd(client_ssl, fd); | |
2011 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 2012 | |
65867078 | 2013 | if (ob->tls_sni) |
3f0945ff | 2014 | { |
65867078 | 2015 | if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 2016 | return FAIL; |
ec4b68e5 | 2017 | if (tls_out.sni == NULL) |
2c9a0e86 PP |
2018 | { |
2019 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
2020 | } | |
ec4b68e5 | 2021 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 2022 | tls_out.sni = NULL; |
3f0945ff PP |
2023 | else |
2024 | { | |
35731706 | 2025 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
2026 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
2027 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
2028 | #else |
2029 | DEBUG(D_tls) | |
2030 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
02d9264f | 2031 | tls_out.sni); |
35731706 | 2032 | #endif |
3f0945ff PP |
2033 | } |
2034 | } | |
2035 | ||
594706ea | 2036 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 JH |
2037 | if (tlsa_dnsa) |
2038 | if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa)) != OK) | |
594706ea JH |
2039 | return rc; |
2040 | #endif | |
2041 | ||
f2de3a33 | 2042 | #ifndef DISABLE_OCSP |
f5d78688 JH |
2043 | /* Request certificate status at connection-time. If the server |
2044 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
b50c8b84 | 2045 | # ifdef EXPERIMENTAL_DANE |
594706ea JH |
2046 | if (request_ocsp) |
2047 | { | |
2048 | const uschar * s; | |
41afb5cb JH |
2049 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
2050 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
2051 | ) |
2052 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
2053 | this means we avoid the OCSP request, we wasted the setup | |
2054 | cost in tls_init(). */ | |
5130845b JH |
2055 | require_ocsp = verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; |
2056 | request_ocsp = require_ocsp | |
2057 | || verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
594706ea JH |
2058 | } |
2059 | } | |
b50c8b84 JH |
2060 | # endif |
2061 | ||
44662487 JH |
2062 | if (request_ocsp) |
2063 | { | |
f5d78688 | 2064 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 JH |
2065 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
2066 | tls_out.ocsp = OCSP_NOT_RESP; | |
2067 | } | |
f5d78688 JH |
2068 | #endif |
2069 | ||
774ef2d7 JH |
2070 | #ifdef EXPERIMENTAL_EVENT |
2071 | client_static_cbinfo->event_action = tb->event_action; | |
a7538db1 | 2072 | #endif |
043b1248 | 2073 | |
059ec3d9 PH |
2074 | /* There doesn't seem to be a built-in timeout on connection. */ |
2075 | ||
2076 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
2077 | sigalrm_seen = FALSE; | |
65867078 | 2078 | alarm(ob->command_timeout); |
817d9f57 | 2079 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
2080 | alarm(0); |
2081 | ||
043b1248 | 2082 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 2083 | if (tlsa_dnsa) |
fde080a4 | 2084 | DANESSL_cleanup(client_ssl); |
043b1248 JH |
2085 | #endif |
2086 | ||
059ec3d9 | 2087 | if (rc <= 0) |
7199e1ee | 2088 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
2089 | |
2090 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
2091 | ||
f69979cf | 2092 | peer_cert(client_ssl, &tls_out, peerdn, sizeof(peerdn)); |
059ec3d9 | 2093 | |
817d9f57 JH |
2094 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
2095 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 2096 | |
9d1c15ef JH |
2097 | /* Record the certificate we presented */ |
2098 | { | |
2099 | X509 * crt = SSL_get_certificate(client_ssl); | |
2100 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
2101 | } | |
2102 | ||
817d9f57 | 2103 | tls_out.active = fd; |
059ec3d9 PH |
2104 | return OK; |
2105 | } | |
2106 | ||
2107 | ||
2108 | ||
2109 | ||
2110 | ||
2111 | /************************************************* | |
2112 | * TLS version of getc * | |
2113 | *************************************************/ | |
2114 | ||
2115 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2116 | it refills the buffer via the SSL reading function. | |
2117 | ||
2118 | Arguments: none | |
2119 | Returns: the next character or EOF | |
817d9f57 JH |
2120 | |
2121 | Only used by the server-side TLS. | |
059ec3d9 PH |
2122 | */ |
2123 | ||
2124 | int | |
2125 | tls_getc(void) | |
2126 | { | |
2127 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
2128 | { | |
2129 | int error; | |
2130 | int inbytes; | |
2131 | ||
817d9f57 | 2132 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 2133 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
2134 | |
2135 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
2136 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
2137 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
2138 | alarm(0); |
2139 | ||
2140 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2141 | closed down, not that the socket itself has been closed down. Revert to | |
2142 | non-SSL handling. */ | |
2143 | ||
2144 | if (error == SSL_ERROR_ZERO_RETURN) | |
2145 | { | |
2146 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2147 | ||
2148 | receive_getc = smtp_getc; | |
2149 | receive_ungetc = smtp_ungetc; | |
2150 | receive_feof = smtp_feof; | |
2151 | receive_ferror = smtp_ferror; | |
58eb016e | 2152 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 2153 | |
817d9f57 JH |
2154 | SSL_free(server_ssl); |
2155 | server_ssl = NULL; | |
2156 | tls_in.active = -1; | |
2157 | tls_in.bits = 0; | |
2158 | tls_in.cipher = NULL; | |
2159 | tls_in.peerdn = NULL; | |
2160 | tls_in.sni = NULL; | |
059ec3d9 PH |
2161 | |
2162 | return smtp_getc(); | |
2163 | } | |
2164 | ||
2165 | /* Handle genuine errors */ | |
2166 | ||
ba084640 PP |
2167 | else if (error == SSL_ERROR_SSL) |
2168 | { | |
2169 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 2170 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
2171 | ssl_xfer_error = 1; |
2172 | return EOF; | |
2173 | } | |
2174 | ||
059ec3d9 PH |
2175 | else if (error != SSL_ERROR_NONE) |
2176 | { | |
2177 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2178 | ssl_xfer_error = 1; | |
2179 | return EOF; | |
2180 | } | |
c80c5570 | 2181 | |
80a47a2c TK |
2182 | #ifndef DISABLE_DKIM |
2183 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2184 | #endif | |
059ec3d9 PH |
2185 | ssl_xfer_buffer_hwm = inbytes; |
2186 | ssl_xfer_buffer_lwm = 0; | |
2187 | } | |
2188 | ||
2189 | /* Something in the buffer; return next uschar */ | |
2190 | ||
2191 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
2192 | } | |
2193 | ||
2194 | ||
2195 | ||
2196 | /************************************************* | |
2197 | * Read bytes from TLS channel * | |
2198 | *************************************************/ | |
2199 | ||
2200 | /* | |
2201 | Arguments: | |
2202 | buff buffer of data | |
2203 | len size of buffer | |
2204 | ||
2205 | Returns: the number of bytes read | |
2206 | -1 after a failed read | |
817d9f57 JH |
2207 | |
2208 | Only used by the client-side TLS. | |
059ec3d9 PH |
2209 | */ |
2210 | ||
2211 | int | |
389ca47a | 2212 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2213 | { |
389ca47a | 2214 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
2215 | int inbytes; |
2216 | int error; | |
2217 | ||
389ca47a | 2218 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2219 | buff, (unsigned int)len); |
059ec3d9 | 2220 | |
389ca47a JH |
2221 | inbytes = SSL_read(ssl, CS buff, len); |
2222 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2223 | |
2224 | if (error == SSL_ERROR_ZERO_RETURN) | |
2225 | { | |
2226 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2227 | return -1; | |
2228 | } | |
2229 | else if (error != SSL_ERROR_NONE) | |
2230 | { | |
2231 | return -1; | |
2232 | } | |
2233 | ||
2234 | return inbytes; | |
2235 | } | |
2236 | ||
2237 | ||
2238 | ||
2239 | ||
2240 | ||
2241 | /************************************************* | |
2242 | * Write bytes down TLS channel * | |
2243 | *************************************************/ | |
2244 | ||
2245 | /* | |
2246 | Arguments: | |
817d9f57 | 2247 | is_server channel specifier |
059ec3d9 PH |
2248 | buff buffer of data |
2249 | len number of bytes | |
2250 | ||
2251 | Returns: the number of bytes after a successful write, | |
2252 | -1 after a failed write | |
817d9f57 JH |
2253 | |
2254 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2255 | */ |
2256 | ||
2257 | int | |
817d9f57 | 2258 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
2259 | { |
2260 | int outbytes; | |
2261 | int error; | |
2262 | int left = len; | |
817d9f57 | 2263 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 2264 | |
c80c5570 | 2265 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
2266 | while (left > 0) |
2267 | { | |
c80c5570 | 2268 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
2269 | outbytes = SSL_write(ssl, CS buff, left); |
2270 | error = SSL_get_error(ssl, outbytes); | |
2271 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2272 | switch (error) | |
2273 | { | |
2274 | case SSL_ERROR_SSL: | |
2275 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2276 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
2277 | return -1; | |
2278 | ||
2279 | case SSL_ERROR_NONE: | |
2280 | left -= outbytes; | |
2281 | buff += outbytes; | |
2282 | break; | |
2283 | ||
2284 | case SSL_ERROR_ZERO_RETURN: | |
2285 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
2286 | return -1; | |
2287 | ||
817d9f57 JH |
2288 | case SSL_ERROR_SYSCALL: |
2289 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
2290 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
2291 | strerror(errno)); | |
2292 | ||
059ec3d9 PH |
2293 | default: |
2294 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
2295 | return -1; | |
2296 | } | |
2297 | } | |
2298 | return len; | |
2299 | } | |
2300 | ||
2301 | ||
2302 | ||
2303 | /************************************************* | |
2304 | * Close down a TLS session * | |
2305 | *************************************************/ | |
2306 | ||
2307 | /* This is also called from within a delivery subprocess forked from the | |
2308 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2309 | would tamper with the SSL session in the parent process). | |
2310 | ||
2311 | Arguments: TRUE if SSL_shutdown is to be called | |
2312 | Returns: nothing | |
817d9f57 JH |
2313 | |
2314 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2315 | */ |
2316 | ||
2317 | void | |
817d9f57 | 2318 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2319 | { |
817d9f57 | 2320 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 2321 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
2322 | |
2323 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
2324 | |
2325 | if (shutdown) | |
2326 | { | |
2327 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 2328 | SSL_shutdown(*sslp); |
059ec3d9 PH |
2329 | } |
2330 | ||
817d9f57 JH |
2331 | SSL_free(*sslp); |
2332 | *sslp = NULL; | |
059ec3d9 | 2333 | |
817d9f57 | 2334 | *fdp = -1; |
059ec3d9 PH |
2335 | } |
2336 | ||
36f12725 NM |
2337 | |
2338 | ||
2339 | ||
3375e053 PP |
2340 | /************************************************* |
2341 | * Let tls_require_ciphers be checked at startup * | |
2342 | *************************************************/ | |
2343 | ||
2344 | /* The tls_require_ciphers option, if set, must be something which the | |
2345 | library can parse. | |
2346 | ||
2347 | Returns: NULL on success, or error message | |
2348 | */ | |
2349 | ||
2350 | uschar * | |
2351 | tls_validate_require_cipher(void) | |
2352 | { | |
2353 | SSL_CTX *ctx; | |
2354 | uschar *s, *expciphers, *err; | |
2355 | ||
2356 | /* this duplicates from tls_init(), we need a better "init just global | |
2357 | state, for no specific purpose" singleton function of our own */ | |
2358 | ||
2359 | SSL_load_error_strings(); | |
2360 | OpenSSL_add_ssl_algorithms(); | |
2361 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
2362 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
2363 | list of available digests. */ | |
2364 | EVP_add_digest(EVP_sha256()); | |
2365 | #endif | |
2366 | ||
2367 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2368 | return NULL; | |
2369 | ||
2370 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2371 | return US"failed to expand tls_require_ciphers"; | |
2372 | ||
2373 | if (!(expciphers && *expciphers)) | |
2374 | return NULL; | |
2375 | ||
2376 | /* normalisation ripped from above */ | |
2377 | s = expciphers; | |
2378 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
2379 | ||
2380 | err = NULL; | |
2381 | ||
2382 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
2383 | if (!ctx) | |
2384 | { | |
2385 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2386 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
2387 | } | |
2388 | ||
2389 | DEBUG(D_tls) | |
2390 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2391 | ||
2392 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
2393 | { | |
2394 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2395 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
2396 | } | |
2397 | ||
2398 | SSL_CTX_free(ctx); | |
2399 | ||
2400 | return err; | |
2401 | } | |
2402 | ||
2403 | ||
2404 | ||
2405 | ||
36f12725 NM |
2406 | /************************************************* |
2407 | * Report the library versions. * | |
2408 | *************************************************/ | |
2409 | ||
2410 | /* There have historically been some issues with binary compatibility in | |
2411 | OpenSSL libraries; if Exim (like many other applications) is built against | |
2412 | one version of OpenSSL but the run-time linker picks up another version, | |
2413 | it can result in serious failures, including crashing with a SIGSEGV. So | |
2414 | report the version found by the compiler and the run-time version. | |
2415 | ||
f64a1e23 PP |
2416 | Note: some OS vendors backport security fixes without changing the version |
2417 | number/string, and the version date remains unchanged. The _build_ date | |
2418 | will change, so we can more usefully assist with version diagnosis by also | |
2419 | reporting the build date. | |
2420 | ||
36f12725 NM |
2421 | Arguments: a FILE* to print the results to |
2422 | Returns: nothing | |
2423 | */ | |
2424 | ||
2425 | void | |
2426 | tls_version_report(FILE *f) | |
2427 | { | |
754a0503 | 2428 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
2429 | " Runtime: %s\n" |
2430 | " : %s\n", | |
754a0503 | 2431 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
2432 | SSLeay_version(SSLEAY_VERSION), |
2433 | SSLeay_version(SSLEAY_BUILT_ON)); | |
2434 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
2435 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
2436 | } |
2437 | ||
9e3331ea TK |
2438 | |
2439 | ||
2440 | ||
2441 | /************************************************* | |
17c76198 | 2442 | * Random number generation * |
9e3331ea TK |
2443 | *************************************************/ |
2444 | ||
2445 | /* Pseudo-random number generation. The result is not expected to be | |
2446 | cryptographically strong but not so weak that someone will shoot themselves | |
2447 | in the foot using it as a nonce in input in some email header scheme or | |
2448 | whatever weirdness they'll twist this into. The result should handle fork() | |
2449 | and avoid repeating sequences. OpenSSL handles that for us. | |
2450 | ||
2451 | Arguments: | |
2452 | max range maximum | |
2453 | Returns a random number in range [0, max-1] | |
2454 | */ | |
2455 | ||
2456 | int | |
17c76198 | 2457 | vaguely_random_number(int max) |
9e3331ea TK |
2458 | { |
2459 | unsigned int r; | |
2460 | int i, needed_len; | |
de6135a0 PP |
2461 | static pid_t pidlast = 0; |
2462 | pid_t pidnow; | |
9e3331ea TK |
2463 | uschar *p; |
2464 | uschar smallbuf[sizeof(r)]; | |
2465 | ||
2466 | if (max <= 1) | |
2467 | return 0; | |
2468 | ||
de6135a0 PP |
2469 | pidnow = getpid(); |
2470 | if (pidnow != pidlast) | |
2471 | { | |
2472 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2473 | is unique for each thread", this doesn't apparently apply across processes, | |
2474 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2475 | Fix per PostgreSQL. */ | |
2476 | if (pidlast != 0) | |
2477 | RAND_cleanup(); | |
2478 | pidlast = pidnow; | |
2479 | } | |
2480 | ||
9e3331ea TK |
2481 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
2482 | if (!RAND_status()) | |
2483 | { | |
2484 | randstuff r; | |
2485 | gettimeofday(&r.tv, NULL); | |
2486 | r.p = getpid(); | |
2487 | ||
2488 | RAND_seed((uschar *)(&r), sizeof(r)); | |
2489 | } | |
2490 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2491 | in the internal PRNG then our options are limited. We could sleep and hope | |
2492 | for entropy to come along (prayer technique) but if the system is so depleted | |
2493 | in the first place then something is likely to just keep taking it. Instead, | |
2494 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2495 | get. */ | |
2496 | ||
2497 | needed_len = sizeof(r); | |
2498 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2499 | asked for a number less than 10. */ | |
2500 | for (r = max, i = 0; r; ++i) | |
2501 | r >>= 1; | |
2502 | i = (i + 7) / 8; | |
2503 | if (i < needed_len) | |
2504 | needed_len = i; | |
2505 | ||
2506 | /* We do not care if crypto-strong */ | |
17c76198 PP |
2507 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
2508 | if (i < 0) | |
2509 | { | |
2510 | DEBUG(D_all) | |
2511 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2512 | return vaguely_random_number_fallback(max); | |
2513 | } | |
2514 | ||
9e3331ea TK |
2515 | r = 0; |
2516 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2517 | { | |
2518 | r *= 256; | |
2519 | r += *p; | |
2520 | } | |
2521 | ||
2522 | /* We don't particularly care about weighted results; if someone wants | |
2523 | smooth distribution and cares enough then they should submit a patch then. */ | |
2524 | return r % max; | |
2525 | } | |
2526 | ||
77bb000f PP |
2527 | |
2528 | ||
2529 | ||
2530 | /************************************************* | |
2531 | * OpenSSL option parse * | |
2532 | *************************************************/ | |
2533 | ||
2534 | /* Parse one option for tls_openssl_options_parse below | |
2535 | ||
2536 | Arguments: | |
2537 | name one option name | |
2538 | value place to store a value for it | |
2539 | Returns success or failure in parsing | |
2540 | */ | |
2541 | ||
2542 | struct exim_openssl_option { | |
2543 | uschar *name; | |
2544 | long value; | |
2545 | }; | |
2546 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2547 | options document which version they were introduced in. Policylet: include | |
2548 | all options unless explicitly for DTLS, let the administrator choose which | |
2549 | to apply. | |
2550 | ||
2551 | This list is current as of: | |
e2fbf4a2 PP |
2552 | ==> 1.0.1b <== |
2553 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2554 | */ | |
77bb000f PP |
2555 | static struct exim_openssl_option exim_openssl_options[] = { |
2556 | /* KEEP SORTED ALPHABETICALLY! */ | |
2557 | #ifdef SSL_OP_ALL | |
73a46702 | 2558 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2559 | #endif |
2560 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2561 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2562 | #endif |
2563 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2564 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2565 | #endif |
2566 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2567 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2568 | #endif |
2569 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2570 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2571 | #endif |
2572 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2573 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2574 | #endif |
2575 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2576 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2577 | #endif |
2578 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2579 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2580 | #endif |
2581 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2582 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2583 | #endif |
2584 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2585 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2586 | #endif |
2587 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2588 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2589 | #endif |
c80c5570 PP |
2590 | #ifdef SSL_OP_NO_COMPRESSION |
2591 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2592 | #endif | |
77bb000f | 2593 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2594 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2595 | #endif |
c0c7b2da PP |
2596 | #ifdef SSL_OP_NO_SSLv2 |
2597 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2598 | #endif | |
2599 | #ifdef SSL_OP_NO_SSLv3 | |
2600 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2601 | #endif | |
2602 | #ifdef SSL_OP_NO_TICKET | |
2603 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2604 | #endif | |
2605 | #ifdef SSL_OP_NO_TLSv1 | |
2606 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2607 | #endif | |
c80c5570 PP |
2608 | #ifdef SSL_OP_NO_TLSv1_1 |
2609 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2610 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2611 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2612 | #else | |
2613 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2614 | #endif | |
2615 | #endif | |
2616 | #ifdef SSL_OP_NO_TLSv1_2 | |
2617 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2618 | #endif | |
e2fbf4a2 PP |
2619 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG |
2620 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2621 | #endif | |
77bb000f | 2622 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2623 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2624 | #endif |
2625 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2626 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2627 | #endif |
2628 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2629 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2630 | #endif |
2631 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2632 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2633 | #endif |
2634 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2635 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2636 | #endif |
2637 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2638 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2639 | #endif |
2640 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2641 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2642 | #endif |
2643 | }; | |
2644 | static int exim_openssl_options_size = | |
2645 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2646 | ||
c80c5570 | 2647 | |
77bb000f PP |
2648 | static BOOL |
2649 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2650 | { | |
2651 | int first = 0; | |
2652 | int last = exim_openssl_options_size; | |
2653 | while (last > first) | |
2654 | { | |
2655 | int middle = (first + last)/2; | |
2656 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2657 | if (c == 0) | |
2658 | { | |
2659 | *value = exim_openssl_options[middle].value; | |
2660 | return TRUE; | |
2661 | } | |
2662 | else if (c > 0) | |
2663 | first = middle + 1; | |
2664 | else | |
2665 | last = middle; | |
2666 | } | |
2667 | return FALSE; | |
2668 | } | |
2669 | ||
2670 | ||
2671 | ||
2672 | ||
2673 | /************************************************* | |
2674 | * OpenSSL option parsing logic * | |
2675 | *************************************************/ | |
2676 | ||
2677 | /* OpenSSL has a number of compatibility options which an administrator might | |
2678 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2679 | we look like log_selector. | |
2680 | ||
2681 | Arguments: | |
2682 | option_spec the administrator-supplied string of options | |
2683 | results ptr to long storage for the options bitmap | |
2684 | Returns success or failure | |
2685 | */ | |
2686 | ||
2687 | BOOL | |
2688 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2689 | { | |
2690 | long result, item; | |
2691 | uschar *s, *end; | |
2692 | uschar keep_c; | |
2693 | BOOL adding, item_parsed; | |
2694 | ||
0e944a0d | 2695 | result = 0L; |
b1770b6e | 2696 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 2697 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
2698 | #ifdef SSL_OP_NO_SSLv2 |
2699 | result |= SSL_OP_NO_SSLv2; | |
2700 | #endif | |
77bb000f PP |
2701 | |
2702 | if (option_spec == NULL) | |
2703 | { | |
2704 | *results = result; | |
2705 | return TRUE; | |
2706 | } | |
2707 | ||
2708 | for (s=option_spec; *s != '\0'; /**/) | |
2709 | { | |
2710 | while (isspace(*s)) ++s; | |
2711 | if (*s == '\0') | |
2712 | break; | |
2713 | if (*s != '+' && *s != '-') | |
2714 | { | |
2715 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 2716 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
2717 | return FALSE; |
2718 | } | |
2719 | adding = *s++ == '+'; | |
2720 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2721 | keep_c = *end; | |
2722 | *end = '\0'; | |
2723 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2724 | if (!item_parsed) | |
2725 | { | |
0e944a0d | 2726 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
2727 | return FALSE; |
2728 | } | |
2729 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2730 | adding ? "adding" : "removing", result, item, s); | |
2731 | if (adding) | |
2732 | result |= item; | |
2733 | else | |
2734 | result &= ~item; | |
2735 | *end = keep_c; | |
2736 | s = end; | |
2737 | } | |
2738 | ||
2739 | *results = result; | |
2740 | return TRUE; | |
2741 | } | |
2742 | ||
9d1c15ef JH |
2743 | /* vi: aw ai sw=2 |
2744 | */ | |
059ec3d9 | 2745 | /* End of tls-openssl.c */ |