Commit | Line | Data |
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059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
5a66c31b | 5 | /* Copyright (c) University of Cambridge 1995 - 2014 */ |
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 |
2dfb468b JH |
41 | #if OPENSSL_VERSION_NUMBER >= 0x010100000L |
42 | # define EXIM_HAVE_OPENSSL_CHECKHOST | |
43 | #endif | |
44 | #if OPENSSL_VERSION_NUMBER >= 0x010000000L \ | |
45 | && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L | |
46 | # define EXIM_HAVE_OPENSSL_CHECKHOST | |
47 | #endif | |
3bcbbbe2 | 48 | |
67791ce4 JH |
49 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
50 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
51 | # define DISABLE_OCSP | |
52 | #endif | |
53 | ||
059ec3d9 PH |
54 | /* Structure for collecting random data for seeding. */ |
55 | ||
56 | typedef struct randstuff { | |
9e3331ea TK |
57 | struct timeval tv; |
58 | pid_t p; | |
059ec3d9 PH |
59 | } randstuff; |
60 | ||
61 | /* Local static variables */ | |
62 | ||
a2ff477a JH |
63 | static BOOL client_verify_callback_called = FALSE; |
64 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
65 | static const uschar *sid_ctx = US"exim"; |
66 | ||
d4f09789 PP |
67 | /* We have three different contexts to care about. |
68 | ||
69 | Simple case: client, `client_ctx` | |
70 | As a client, we can be doing a callout or cut-through delivery while receiving | |
71 | a message. So we have a client context, which should have options initialised | |
72 | from the SMTP Transport. | |
73 | ||
74 | Server: | |
75 | There are two cases: with and without ServerNameIndication from the client. | |
76 | Given TLS SNI, we can be using different keys, certs and various other | |
77 | configuration settings, because they're re-expanded with $tls_sni set. This | |
78 | allows vhosting with TLS. This SNI is sent in the handshake. | |
79 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
80 | So as a server, we start out using `server_ctx`. | |
81 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
82 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
83 | configuration. | |
84 | */ | |
85 | ||
817d9f57 JH |
86 | static SSL_CTX *client_ctx = NULL; |
87 | static SSL_CTX *server_ctx = NULL; | |
88 | static SSL *client_ssl = NULL; | |
89 | static SSL *server_ssl = NULL; | |
389ca47a | 90 | |
35731706 | 91 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 92 | static SSL_CTX *server_sni = NULL; |
35731706 | 93 | #endif |
059ec3d9 PH |
94 | |
95 | static char ssl_errstring[256]; | |
96 | ||
97 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
98 | static BOOL client_verify_optional = FALSE; |
99 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 100 | |
f5d78688 | 101 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
102 | |
103 | ||
7be682ca PP |
104 | typedef struct tls_ext_ctx_cb { |
105 | uschar *certificate; | |
106 | uschar *privatekey; | |
f2de3a33 | 107 | #ifndef DISABLE_OCSP |
f5d78688 JH |
108 | BOOL is_server; |
109 | union { | |
110 | struct { | |
111 | uschar *file; | |
112 | uschar *file_expanded; | |
113 | OCSP_RESPONSE *response; | |
114 | } server; | |
115 | struct { | |
44662487 JH |
116 | X509_STORE *verify_store; /* non-null if status requested */ |
117 | BOOL verify_required; | |
f5d78688 JH |
118 | } client; |
119 | } u_ocsp; | |
3f7eeb86 | 120 | #endif |
7be682ca PP |
121 | uschar *dhparam; |
122 | /* these are cached from first expand */ | |
123 | uschar *server_cipher_list; | |
124 | /* only passed down to tls_error: */ | |
125 | host_item *host; | |
e51c7be2 JH |
126 | |
127 | #ifdef EXPERIMENTAL_CERTNAMES | |
128 | uschar * verify_cert_hostnames; | |
129 | #endif | |
774ef2d7 | 130 | #ifdef EXPERIMENTAL_EVENT |
a7538db1 JH |
131 | uschar * event_action; |
132 | #endif | |
7be682ca PP |
133 | } tls_ext_ctx_cb; |
134 | ||
135 | /* should figure out a cleanup of API to handle state preserved per | |
136 | implementation, for various reasons, which can be void * in the APIs. | |
137 | For now, we hack around it. */ | |
817d9f57 JH |
138 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
139 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
140 | |
141 | static int | |
983207c1 JH |
142 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
143 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ); | |
059ec3d9 | 144 | |
3f7eeb86 | 145 | /* Callbacks */ |
3bcbbbe2 | 146 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 147 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 148 | #endif |
f2de3a33 | 149 | #ifndef DISABLE_OCSP |
f5d78688 | 150 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
151 | #endif |
152 | ||
059ec3d9 PH |
153 | |
154 | /************************************************* | |
155 | * Handle TLS error * | |
156 | *************************************************/ | |
157 | ||
158 | /* Called from lots of places when errors occur before actually starting to do | |
159 | the TLS handshake, that is, while the session is still in clear. Always returns | |
160 | DEFER for a server and FAIL for a client so that most calls can use "return | |
161 | tls_error(...)" to do this processing and then give an appropriate return. A | |
162 | single function is used for both server and client, because it is called from | |
163 | some shared functions. | |
164 | ||
165 | Argument: | |
166 | prefix text to include in the logged error | |
167 | host NULL if setting up a server; | |
168 | the connected host if setting up a client | |
7199e1ee | 169 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
170 | |
171 | Returns: OK/DEFER/FAIL | |
172 | */ | |
173 | ||
174 | static int | |
7199e1ee | 175 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 176 | { |
c562fd30 | 177 | if (!msg) |
7199e1ee TF |
178 | { |
179 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 180 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
181 | } |
182 | ||
c562fd30 JH |
183 | if (host) |
184 | { | |
185 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s): %s", | |
186 | host->name, host->address, prefix, msg); | |
187 | return FAIL; | |
188 | } | |
189 | else | |
059ec3d9 | 190 | { |
7199e1ee | 191 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 192 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee | 193 | conn_info += 5; |
c562fd30 | 194 | /* I'd like to get separated H= here, but too hard for now */ |
7199e1ee TF |
195 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", |
196 | conn_info, prefix, msg); | |
059ec3d9 PH |
197 | return DEFER; |
198 | } | |
059ec3d9 PH |
199 | } |
200 | ||
201 | ||
202 | ||
203 | /************************************************* | |
204 | * Callback to generate RSA key * | |
205 | *************************************************/ | |
206 | ||
207 | /* | |
208 | Arguments: | |
209 | s SSL connection | |
210 | export not used | |
211 | keylength keylength | |
212 | ||
213 | Returns: pointer to generated key | |
214 | */ | |
215 | ||
216 | static RSA * | |
217 | rsa_callback(SSL *s, int export, int keylength) | |
218 | { | |
219 | RSA *rsa_key; | |
220 | export = export; /* Shut picky compilers up */ | |
221 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
222 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
223 | if (rsa_key == NULL) | |
224 | { | |
225 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
226 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
227 | ssl_errstring); | |
228 | return NULL; | |
229 | } | |
230 | return rsa_key; | |
231 | } | |
232 | ||
233 | ||
234 | ||
f5d78688 | 235 | /* Extreme debug |
f2de3a33 | 236 | #ifndef DISABLE_OCSP |
f5d78688 JH |
237 | void |
238 | x509_store_dump_cert_s_names(X509_STORE * store) | |
239 | { | |
240 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
241 | int i; | |
242 | static uschar name[256]; | |
243 | ||
244 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
245 | { | |
246 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
247 | if(tmp_obj->type == X509_LU_X509) | |
248 | { | |
249 | X509 * current_cert= tmp_obj->data.x509; | |
250 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
251 | debug_printf(" %s\n", name); | |
252 | } | |
253 | } | |
254 | } | |
255 | #endif | |
256 | */ | |
257 | ||
059ec3d9 PH |
258 | |
259 | /************************************************* | |
260 | * Callback for verification * | |
261 | *************************************************/ | |
262 | ||
263 | /* The SSL library does certificate verification if set up to do so. This | |
264 | callback has the current yes/no state is in "state". If verification succeeded, | |
265 | we set up the tls_peerdn string. If verification failed, what happens depends | |
266 | on whether the client is required to present a verifiable certificate or not. | |
267 | ||
268 | If verification is optional, we change the state to yes, but still log the | |
269 | verification error. For some reason (it really would help to have proper | |
270 | documentation of OpenSSL), this callback function then gets called again, this | |
271 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
272 | value, but we must take care not to set the private verified flag on the second | |
273 | time through. | |
274 | ||
275 | Note: this function is not called if the client fails to present a certificate | |
276 | when asked. We get here only if a certificate has been received. Handling of | |
277 | optional verification for this case is done when requesting SSL to verify, by | |
278 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
279 | ||
a7538db1 JH |
280 | May be called multiple times for different issues with a certificate, even |
281 | for a given "depth" in the certificate chain. | |
282 | ||
059ec3d9 PH |
283 | Arguments: |
284 | state current yes/no state as 1/0 | |
285 | x509ctx certificate information. | |
a2ff477a | 286 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
287 | |
288 | Returns: 1 if verified, 0 if not | |
289 | */ | |
290 | ||
291 | static int | |
421aff85 JH |
292 | verify_callback(int state, X509_STORE_CTX *x509ctx, |
293 | tls_support *tlsp, BOOL *calledp, BOOL *optionalp) | |
059ec3d9 | 294 | { |
421aff85 | 295 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 296 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
059ec3d9 | 297 | static uschar txt[256]; |
b30275b8 JH |
298 | #ifdef EXPERIMENTAL_EVENT |
299 | uschar * ev; | |
300 | uschar * yield; | |
301 | #endif | |
059ec3d9 | 302 | |
e51c7be2 | 303 | X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); |
059ec3d9 PH |
304 | |
305 | if (state == 0) | |
306 | { | |
307 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
a7538db1 | 308 | depth, |
421aff85 | 309 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), |
059ec3d9 | 310 | txt); |
a2ff477a JH |
311 | tlsp->certificate_verified = FALSE; |
312 | *calledp = TRUE; | |
9d1c15ef JH |
313 | if (!*optionalp) |
314 | { | |
421aff85 | 315 | tlsp->peercert = X509_dup(cert); |
9d1c15ef JH |
316 | return 0; /* reject */ |
317 | } | |
059ec3d9 PH |
318 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
319 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
320 | } |
321 | ||
a7538db1 | 322 | else if (depth != 0) |
059ec3d9 | 323 | { |
a7538db1 | 324 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, txt); |
f2de3a33 | 325 | #ifndef DISABLE_OCSP |
f5d78688 JH |
326 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
327 | { /* client, wanting stapling */ | |
328 | /* Add the server cert's signing chain as the one | |
329 | for the verification of the OCSP stapled information. */ | |
330 | ||
331 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
421aff85 | 332 | cert)) |
f5d78688 JH |
333 | ERR_clear_error(); |
334 | } | |
a7538db1 | 335 | #endif |
774ef2d7 | 336 | #ifdef EXPERIMENTAL_EVENT |
723fe533 JH |
337 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; |
338 | if (ev) | |
a7538db1 JH |
339 | { |
340 | tlsp->peercert = X509_dup(cert); | |
b30275b8 | 341 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) |
a7538db1 JH |
342 | { |
343 | log_write(0, LOG_MAIN, "SSL verify denied by event-action: " | |
b30275b8 | 344 | "depth=%d cert=%s: %s", depth, txt, yield); |
a7538db1 JH |
345 | tlsp->certificate_verified = FALSE; |
346 | *calledp = TRUE; | |
347 | return 0; /* reject */ | |
348 | } | |
349 | X509_free(tlsp->peercert); | |
350 | tlsp->peercert = NULL; | |
351 | } | |
f5d78688 | 352 | #endif |
059ec3d9 PH |
353 | } |
354 | else | |
355 | { | |
e51c7be2 JH |
356 | #ifdef EXPERIMENTAL_CERTNAMES |
357 | uschar * verify_cert_hostnames; | |
358 | #endif | |
359 | ||
a2ff477a | 360 | tlsp->peerdn = txt; |
421aff85 | 361 | tlsp->peercert = X509_dup(cert); |
e51c7be2 JH |
362 | |
363 | #ifdef EXPERIMENTAL_CERTNAMES | |
364 | if ( tlsp == &tls_out | |
365 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
366 | /* client, wanting hostname check */ | |
367 | ||
2dfb468b | 368 | # if EXIM_HAVE_OPENSSL_CHECKHOST |
d8e7834a JH |
369 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
370 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
371 | # endif | |
e51c7be2 JH |
372 | { |
373 | int sep = 0; | |
374 | uschar * list = verify_cert_hostnames; | |
375 | uschar * name; | |
d8e7834a JH |
376 | int rc; |
377 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
378 | if ((rc = X509_check_host(cert, name, 0, | |
379 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS))) | |
380 | { | |
381 | if (rc < 0) | |
382 | { | |
383 | log_write(0, LOG_MAIN, "SSL verify error: internal error\n"); | |
384 | name = NULL; | |
385 | } | |
e51c7be2 | 386 | break; |
d8e7834a | 387 | } |
e51c7be2 JH |
388 | if (!name) |
389 | { | |
390 | log_write(0, LOG_MAIN, | |
391 | "SSL verify error: certificate name mismatch: \"%s\"\n", txt); | |
392 | return 0; /* reject */ | |
393 | } | |
394 | } | |
395 | # else | |
396 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) | |
397 | { | |
398 | log_write(0, LOG_MAIN, | |
399 | "SSL verify error: certificate name mismatch: \"%s\"\n", txt); | |
400 | return 0; /* reject */ | |
401 | } | |
402 | # endif | |
e5cccda9 | 403 | #endif /*EXPERIMENTAL_CERTNAMES*/ |
e51c7be2 | 404 | |
774ef2d7 | 405 | #ifdef EXPERIMENTAL_EVENT |
723fe533 JH |
406 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; |
407 | if (ev) | |
b30275b8 | 408 | if ((yield = event_raise(ev, US"tls:cert", US"0"))) |
a7538db1 JH |
409 | { |
410 | log_write(0, LOG_MAIN, "SSL verify denied by event-action: " | |
b30275b8 | 411 | "depth=0 cert=%s: %s", txt, yield); |
a7538db1 JH |
412 | tlsp->certificate_verified = FALSE; |
413 | *calledp = TRUE; | |
414 | return 0; /* reject */ | |
415 | } | |
e51c7be2 JH |
416 | #endif |
417 | ||
93dcb1c2 JH |
418 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
419 | *calledp ? "" : " authenticated", txt); | |
420 | if (!*calledp) tlsp->certificate_verified = TRUE; | |
421 | *calledp = TRUE; | |
059ec3d9 PH |
422 | } |
423 | ||
a7538db1 | 424 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
425 | } |
426 | ||
a2ff477a JH |
427 | static int |
428 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
429 | { | |
f5d78688 | 430 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); |
a2ff477a JH |
431 | } |
432 | ||
433 | static int | |
434 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
435 | { | |
f5d78688 | 436 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); |
a2ff477a JH |
437 | } |
438 | ||
059ec3d9 | 439 | |
e5cccda9 | 440 | #ifdef EXPERIMENTAL_DANE |
53a7196b | 441 | |
e5cccda9 JH |
442 | /* This gets called *by* the dane library verify callback, which interposes |
443 | itself. | |
444 | */ | |
445 | static int | |
446 | verify_callback_client_dane(int state, X509_STORE_CTX * x509ctx) | |
447 | { | |
448 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
449 | static uschar txt[256]; | |
774ef2d7 | 450 | #ifdef EXPERIMENTAL_EVENT |
83b27293 | 451 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
b30275b8 | 452 | uschar * yield; |
83b27293 | 453 | #endif |
e5cccda9 JH |
454 | |
455 | X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); | |
456 | ||
457 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", txt); | |
458 | tls_out.peerdn = txt; | |
459 | tls_out.peercert = X509_dup(cert); | |
460 | ||
774ef2d7 | 461 | #ifdef EXPERIMENTAL_EVENT |
83b27293 JH |
462 | if (client_static_cbinfo->event_action) |
463 | { | |
b30275b8 JH |
464 | if ((yield = event_raise(client_static_cbinfo->event_action, |
465 | US"tls:cert", string_sprintf("%d", depth)))) | |
83b27293 JH |
466 | { |
467 | log_write(0, LOG_MAIN, "DANE verify denied by event-action: " | |
b30275b8 | 468 | "depth=%d cert=%s: %s", depth, txt, yield); |
83b27293 JH |
469 | tls_out.certificate_verified = FALSE; |
470 | return 0; /* reject */ | |
471 | } | |
472 | if (depth != 0) | |
473 | { | |
474 | X509_free(tls_out.peercert); | |
475 | tls_out.peercert = NULL; | |
476 | } | |
477 | } | |
478 | #endif | |
479 | ||
e5cccda9 | 480 | if (state == 1) |
53a7196b | 481 | tls_out.dane_verified = |
e5cccda9 JH |
482 | tls_out.certificate_verified = TRUE; |
483 | return 1; | |
484 | } | |
53a7196b JH |
485 | |
486 | #endif /*EXPERIMENTAL_DANE*/ | |
e5cccda9 | 487 | |
059ec3d9 PH |
488 | |
489 | /************************************************* | |
490 | * Information callback * | |
491 | *************************************************/ | |
492 | ||
493 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
494 | are doing. We copy the string to the debugging output when TLS debugging has |
495 | been requested. | |
059ec3d9 PH |
496 | |
497 | Arguments: | |
498 | s the SSL connection | |
499 | where | |
500 | ret | |
501 | ||
502 | Returns: nothing | |
503 | */ | |
504 | ||
505 | static void | |
506 | info_callback(SSL *s, int where, int ret) | |
507 | { | |
508 | where = where; | |
509 | ret = ret; | |
510 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
511 | } | |
512 | ||
513 | ||
514 | ||
515 | /************************************************* | |
516 | * Initialize for DH * | |
517 | *************************************************/ | |
518 | ||
519 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
520 | ||
521 | Arguments: | |
a799883d | 522 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 523 | host connected host, if client; NULL if server |
059ec3d9 PH |
524 | |
525 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
526 | */ | |
527 | ||
528 | static BOOL | |
a799883d | 529 | init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host) |
059ec3d9 | 530 | { |
059ec3d9 PH |
531 | BIO *bio; |
532 | DH *dh; | |
533 | uschar *dhexpanded; | |
a799883d | 534 | const char *pem; |
059ec3d9 PH |
535 | |
536 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
537 | return FALSE; | |
538 | ||
0df4ab80 | 539 | if (!dhexpanded || !*dhexpanded) |
a799883d | 540 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 541 | else if (dhexpanded[0] == '/') |
059ec3d9 | 542 | { |
0df4ab80 | 543 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 544 | { |
7199e1ee | 545 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
546 | host, US strerror(errno)); |
547 | return FALSE; | |
059ec3d9 | 548 | } |
a799883d PP |
549 | } |
550 | else | |
551 | { | |
552 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 553 | { |
a799883d PP |
554 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
555 | return TRUE; | |
059ec3d9 | 556 | } |
a799883d | 557 | |
0df4ab80 | 558 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
559 | { |
560 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
561 | host, US strerror(errno)); | |
562 | return FALSE; | |
563 | } | |
564 | bio = BIO_new_mem_buf(CS pem, -1); | |
565 | } | |
566 | ||
0df4ab80 | 567 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 568 | { |
059ec3d9 | 569 | BIO_free(bio); |
a799883d PP |
570 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
571 | host, NULL); | |
572 | return FALSE; | |
573 | } | |
574 | ||
575 | /* Even if it is larger, we silently return success rather than cause things | |
576 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
577 | * debatable choice. */ | |
578 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
579 | { | |
580 | DEBUG(D_tls) | |
581 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
582 | 8*DH_size(dh), tls_dh_max_bits); | |
583 | } | |
584 | else | |
585 | { | |
586 | SSL_CTX_set_tmp_dh(sctx, dh); | |
587 | DEBUG(D_tls) | |
588 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
589 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
590 | } |
591 | ||
a799883d PP |
592 | DH_free(dh); |
593 | BIO_free(bio); | |
594 | ||
595 | return TRUE; | |
059ec3d9 PH |
596 | } |
597 | ||
598 | ||
599 | ||
600 | ||
f2de3a33 | 601 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
602 | /************************************************* |
603 | * Load OCSP information into state * | |
604 | *************************************************/ | |
605 | ||
f5d78688 | 606 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
607 | caller has determined this is needed. Checks validity. Debugs a message |
608 | if invalid. | |
609 | ||
610 | ASSUMES: single response, for single cert. | |
611 | ||
612 | Arguments: | |
613 | sctx the SSL_CTX* to update | |
614 | cbinfo various parts of session state | |
615 | expanded the filename putatively holding an OCSP response | |
616 | ||
617 | */ | |
618 | ||
619 | static void | |
f5d78688 | 620 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 PP |
621 | { |
622 | BIO *bio; | |
623 | OCSP_RESPONSE *resp; | |
624 | OCSP_BASICRESP *basic_response; | |
625 | OCSP_SINGLERESP *single_response; | |
626 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
627 | X509_STORE *store; | |
628 | unsigned long verify_flags; | |
629 | int status, reason, i; | |
630 | ||
f5d78688 JH |
631 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
632 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 633 | { |
f5d78688 JH |
634 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
635 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
636 | } |
637 | ||
f5d78688 | 638 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); |
3f7eeb86 PP |
639 | if (!bio) |
640 | { | |
641 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 642 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
643 | return; |
644 | } | |
645 | ||
646 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
647 | BIO_free(bio); | |
648 | if (!resp) | |
649 | { | |
650 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
651 | return; | |
652 | } | |
653 | ||
654 | status = OCSP_response_status(resp); | |
655 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
656 | { | |
657 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
658 | OCSP_response_status_str(status), status); | |
f5d78688 | 659 | goto bad; |
3f7eeb86 PP |
660 | } |
661 | ||
662 | basic_response = OCSP_response_get1_basic(resp); | |
663 | if (!basic_response) | |
664 | { | |
665 | DEBUG(D_tls) | |
666 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 667 | goto bad; |
3f7eeb86 PP |
668 | } |
669 | ||
670 | store = SSL_CTX_get_cert_store(sctx); | |
671 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
672 | ||
673 | /* May need to expose ability to adjust those flags? | |
674 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
675 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
676 | ||
677 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
678 | if (i <= 0) | |
679 | { | |
680 | DEBUG(D_tls) { | |
681 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
682 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
683 | } |
684 | goto bad; | |
3f7eeb86 PP |
685 | } |
686 | ||
687 | /* Here's the simplifying assumption: there's only one response, for the | |
688 | one certificate we use, and nothing for anything else in a chain. If this | |
689 | proves false, we need to extract a cert id from our issued cert | |
690 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
691 | right cert in the stack and then calls OCSP_single_get0_status()). | |
692 | ||
693 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
694 | single_response = OCSP_resp_get0(basic_response, 0); | |
695 | if (!single_response) | |
696 | { | |
697 | DEBUG(D_tls) | |
698 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 699 | goto bad; |
3f7eeb86 PP |
700 | } |
701 | ||
702 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 703 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 704 | { |
f5d78688 JH |
705 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
706 | OCSP_cert_status_str(status), status, | |
707 | OCSP_crl_reason_str(reason), reason); | |
708 | goto bad; | |
3f7eeb86 PP |
709 | } |
710 | ||
711 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
712 | { | |
713 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 714 | goto bad; |
3f7eeb86 PP |
715 | } |
716 | ||
f5d78688 | 717 | supply_response: |
018058b2 | 718 | cbinfo->u_ocsp.server.response = resp; |
f5d78688 JH |
719 | return; |
720 | ||
721 | bad: | |
018058b2 JH |
722 | if (running_in_test_harness) |
723 | { | |
724 | extern char ** environ; | |
725 | uschar ** p; | |
726 | for (p = USS environ; *p != NULL; p++) | |
727 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
728 | { | |
729 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
730 | goto supply_response; | |
731 | } | |
732 | } | |
f5d78688 | 733 | return; |
3f7eeb86 | 734 | } |
f2de3a33 | 735 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
736 | |
737 | ||
738 | ||
739 | ||
7be682ca PP |
740 | /************************************************* |
741 | * Expand key and cert file specs * | |
742 | *************************************************/ | |
743 | ||
f5d78688 | 744 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
745 | new context, if Server Name Indication was used and tls_sni was seen in |
746 | the certificate string. | |
747 | ||
748 | Arguments: | |
749 | sctx the SSL_CTX* to update | |
750 | cbinfo various parts of session state | |
751 | ||
752 | Returns: OK/DEFER/FAIL | |
753 | */ | |
754 | ||
755 | static int | |
3f7eeb86 | 756 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
757 | { |
758 | uschar *expanded; | |
759 | ||
760 | if (cbinfo->certificate == NULL) | |
761 | return OK; | |
762 | ||
d9b2312b JH |
763 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
764 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
765 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
766 | ) | |
7be682ca PP |
767 | reexpand_tls_files_for_sni = TRUE; |
768 | ||
769 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
770 | return DEFER; | |
771 | ||
772 | if (expanded != NULL) | |
773 | { | |
774 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
775 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
776 | return tls_error(string_sprintf( | |
777 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
778 | cbinfo->host, NULL); | |
779 | } | |
780 | ||
781 | if (cbinfo->privatekey != NULL && | |
782 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
783 | return DEFER; | |
784 | ||
785 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
786 | of the expansion is an empty string, ignore it also, and assume the private | |
787 | key is in the same file as the certificate. */ | |
788 | ||
789 | if (expanded != NULL && *expanded != 0) | |
790 | { | |
791 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
792 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
793 | return tls_error(string_sprintf( | |
794 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
795 | } | |
796 | ||
f2de3a33 | 797 | #ifndef DISABLE_OCSP |
f5d78688 | 798 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) |
3f7eeb86 | 799 | { |
f5d78688 | 800 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) |
3f7eeb86 PP |
801 | return DEFER; |
802 | ||
803 | if (expanded != NULL && *expanded != 0) | |
804 | { | |
805 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f5d78688 JH |
806 | if (cbinfo->u_ocsp.server.file_expanded && |
807 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 PP |
808 | { |
809 | DEBUG(D_tls) | |
810 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
811 | } else { | |
812 | ocsp_load_response(sctx, cbinfo, expanded); | |
813 | } | |
814 | } | |
815 | } | |
816 | #endif | |
817 | ||
7be682ca PP |
818 | return OK; |
819 | } | |
820 | ||
821 | ||
822 | ||
823 | ||
824 | /************************************************* | |
825 | * Callback to handle SNI * | |
826 | *************************************************/ | |
827 | ||
828 | /* Called when acting as server during the TLS session setup if a Server Name | |
829 | Indication extension was sent by the client. | |
830 | ||
831 | API documentation is OpenSSL s_server.c implementation. | |
832 | ||
833 | Arguments: | |
834 | s SSL* of the current session | |
835 | ad unknown (part of OpenSSL API) (unused) | |
836 | arg Callback of "our" registered data | |
837 | ||
838 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
839 | */ | |
840 | ||
3bcbbbe2 | 841 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
842 | static int |
843 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
844 | { | |
845 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 846 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 847 | int rc; |
3f0945ff | 848 | int old_pool = store_pool; |
7be682ca PP |
849 | |
850 | if (!servername) | |
851 | return SSL_TLSEXT_ERR_OK; | |
852 | ||
3f0945ff | 853 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
854 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
855 | ||
856 | /* Make the extension value available for expansion */ | |
3f0945ff | 857 | store_pool = POOL_PERM; |
817d9f57 | 858 | tls_in.sni = string_copy(US servername); |
3f0945ff | 859 | store_pool = old_pool; |
7be682ca PP |
860 | |
861 | if (!reexpand_tls_files_for_sni) | |
862 | return SSL_TLSEXT_ERR_OK; | |
863 | ||
864 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
865 | not confident that memcpy wouldn't break some internal reference counting. | |
866 | Especially since there's a references struct member, which would be off. */ | |
867 | ||
0df4ab80 | 868 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7be682ca PP |
869 | { |
870 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
871 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
872 | return SSL_TLSEXT_ERR_NOACK; | |
873 | } | |
874 | ||
875 | /* Not sure how many of these are actually needed, since SSL object | |
876 | already exists. Might even need this selfsame callback, for reneg? */ | |
877 | ||
817d9f57 JH |
878 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
879 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
880 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
881 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
882 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
883 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
7be682ca | 884 | if (cbinfo->server_cipher_list) |
817d9f57 | 885 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
f2de3a33 | 886 | #ifndef DISABLE_OCSP |
f5d78688 | 887 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 888 | { |
f5d78688 | 889 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 890 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
891 | } |
892 | #endif | |
7be682ca | 893 | |
983207c1 | 894 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server); |
7be682ca PP |
895 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
896 | ||
3f7eeb86 PP |
897 | /* do this after setup_certs, because this can require the certs for verifying |
898 | OCSP information. */ | |
817d9f57 | 899 | rc = tls_expand_session_files(server_sni, cbinfo); |
7be682ca PP |
900 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
901 | ||
0df4ab80 JH |
902 | if (!init_dh(server_sni, cbinfo->dhparam, NULL)) |
903 | return SSL_TLSEXT_ERR_NOACK; | |
a799883d | 904 | |
7be682ca | 905 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 906 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
907 | |
908 | return SSL_TLSEXT_ERR_OK; | |
909 | } | |
3bcbbbe2 | 910 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
911 | |
912 | ||
913 | ||
914 | ||
f2de3a33 | 915 | #ifndef DISABLE_OCSP |
f5d78688 | 916 | |
3f7eeb86 PP |
917 | /************************************************* |
918 | * Callback to handle OCSP Stapling * | |
919 | *************************************************/ | |
920 | ||
921 | /* Called when acting as server during the TLS session setup if the client | |
922 | requests OCSP information with a Certificate Status Request. | |
923 | ||
924 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
925 | project. | |
926 | ||
927 | */ | |
928 | ||
929 | static int | |
f5d78688 | 930 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
931 | { |
932 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
933 | uschar *response_der; | |
934 | int response_der_len; | |
935 | ||
af4a1bca JH |
936 | DEBUG(D_tls) |
937 | debug_printf("Received TLS status request (OCSP stapling); %s response.", | |
f5d78688 JH |
938 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
939 | ||
44662487 | 940 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 941 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
942 | return SSL_TLSEXT_ERR_NOACK; |
943 | ||
944 | response_der = NULL; | |
44662487 JH |
945 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, |
946 | &response_der); | |
3f7eeb86 PP |
947 | if (response_der_len <= 0) |
948 | return SSL_TLSEXT_ERR_NOACK; | |
949 | ||
5e55c7a9 | 950 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 951 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
952 | return SSL_TLSEXT_ERR_OK; |
953 | } | |
954 | ||
3f7eeb86 | 955 | |
f5d78688 JH |
956 | static void |
957 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
958 | { | |
959 | BIO_printf(bp, "\t%s: ", str); | |
960 | ASN1_GENERALIZEDTIME_print(bp, time); | |
961 | BIO_puts(bp, "\n"); | |
962 | } | |
963 | ||
964 | static int | |
965 | tls_client_stapling_cb(SSL *s, void *arg) | |
966 | { | |
967 | tls_ext_ctx_cb * cbinfo = arg; | |
968 | const unsigned char * p; | |
969 | int len; | |
970 | OCSP_RESPONSE * rsp; | |
971 | OCSP_BASICRESP * bs; | |
972 | int i; | |
973 | ||
974 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
975 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
976 | if(!p) | |
977 | { | |
44662487 JH |
978 | /* Expect this when we requested ocsp but got none */ |
979 | if ( cbinfo->u_ocsp.client.verify_required | |
980 | && log_extra_selector & LX_tls_cipher) | |
981 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); | |
f5d78688 JH |
982 | else |
983 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 984 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 985 | } |
018058b2 | 986 | |
f5d78688 JH |
987 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
988 | { | |
018058b2 | 989 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 | 990 | if (log_extra_selector & LX_tls_cipher) |
1eca31ca | 991 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
992 | else |
993 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
994 | return 0; | |
995 | } | |
996 | ||
997 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
998 | { | |
018058b2 | 999 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 | 1000 | if (log_extra_selector & LX_tls_cipher) |
1eca31ca | 1001 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1002 | else |
1003 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1004 | OCSP_RESPONSE_free(rsp); | |
1005 | return 0; | |
1006 | } | |
1007 | ||
1008 | /* We'd check the nonce here if we'd put one in the request. */ | |
1009 | /* However that would defeat cacheability on the server so we don't. */ | |
1010 | ||
f5d78688 JH |
1011 | /* This section of code reworked from OpenSSL apps source; |
1012 | The OpenSSL Project retains copyright: | |
1013 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1014 | */ | |
1015 | { | |
1016 | BIO * bp = NULL; | |
f5d78688 JH |
1017 | int status, reason; |
1018 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1019 | ||
1020 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
1021 | ||
1022 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1023 | ||
1024 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1025 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1026 | ||
44662487 JH |
1027 | if ((i = OCSP_basic_verify(bs, NULL, |
1028 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
f5d78688 | 1029 | { |
018058b2 | 1030 | tls_out.ocsp = OCSP_FAILED; |
1eca31ca JH |
1031 | if (log_extra_selector & LX_tls_cipher) |
1032 | log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable"); | |
f5d78688 JH |
1033 | BIO_printf(bp, "OCSP response verify failure\n"); |
1034 | ERR_print_errors(bp); | |
44662487 | 1035 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 JH |
1036 | goto out; |
1037 | } | |
1038 | ||
1039 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1040 | ||
1041 | { | |
1042 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
1043 | OCSP_SINGLERESP * single; | |
1044 | ||
1045 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
1046 | { | |
018058b2 | 1047 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1048 | log_write(0, LOG_MAIN, "OCSP stapling " |
1049 | "with multiple responses not handled"); | |
1050 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
f5d78688 JH |
1051 | goto out; |
1052 | } | |
1053 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1054 | status = OCSP_single_get0_status(single, &reason, &rev, |
1055 | &thisupd, &nextupd); | |
f5d78688 JH |
1056 | } |
1057 | ||
f5d78688 JH |
1058 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1059 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1060 | if (!OCSP_check_validity(thisupd, nextupd, |
1061 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1062 | { |
018058b2 | 1063 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1064 | DEBUG(D_tls) ERR_print_errors(bp); |
1065 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
44662487 | 1066 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1067 | } |
44662487 | 1068 | else |
f5d78688 | 1069 | { |
44662487 JH |
1070 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1071 | OCSP_cert_status_str(status)); | |
1072 | switch(status) | |
1073 | { | |
1074 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1075 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1076 | i = 1; |
44662487 JH |
1077 | break; |
1078 | case V_OCSP_CERTSTATUS_REVOKED: | |
018058b2 | 1079 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1080 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1081 | reason != -1 ? "; reason: " : "", | |
1082 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1083 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
1084 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1085 | break; | |
1086 | default: | |
018058b2 | 1087 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1088 | log_write(0, LOG_MAIN, |
1089 | "Server certificate status unknown, in OCSP stapling"); | |
1090 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1091 | break; | |
1092 | } | |
f5d78688 JH |
1093 | } |
1094 | out: | |
1095 | BIO_free(bp); | |
1096 | } | |
1097 | ||
1098 | OCSP_RESPONSE_free(rsp); | |
1099 | return i; | |
1100 | } | |
f2de3a33 | 1101 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1102 | |
1103 | ||
059ec3d9 PH |
1104 | /************************************************* |
1105 | * Initialize for TLS * | |
1106 | *************************************************/ | |
1107 | ||
e51c7be2 JH |
1108 | /* Called from both server and client code, to do preliminary initialization |
1109 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1110 | |
1111 | Arguments: | |
946ecbe0 | 1112 | ctxp returned SSL context |
059ec3d9 PH |
1113 | host connected host, if client; NULL if server |
1114 | dhparam DH parameter file | |
1115 | certificate certificate file | |
1116 | privatekey private key | |
f5d78688 | 1117 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1118 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1119 | cbp place to put allocated callback context |
059ec3d9 PH |
1120 | |
1121 | Returns: OK/DEFER/FAIL | |
1122 | */ | |
1123 | ||
1124 | static int | |
817d9f57 | 1125 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1126 | uschar *privatekey, |
f2de3a33 | 1127 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1128 | uschar *ocsp_file, |
1129 | #endif | |
817d9f57 | 1130 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 1131 | { |
77bb000f | 1132 | long init_options; |
7be682ca | 1133 | int rc; |
77bb000f | 1134 | BOOL okay; |
a7538db1 | 1135 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1136 | |
1137 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1138 | cbinfo->certificate = certificate; | |
1139 | cbinfo->privatekey = privatekey; | |
f2de3a33 | 1140 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1141 | if ((cbinfo->is_server = host==NULL)) |
1142 | { | |
1143 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1144 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1145 | cbinfo->u_ocsp.server.response = NULL; | |
1146 | } | |
1147 | else | |
1148 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1149 | #endif |
7be682ca | 1150 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1151 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1152 | cbinfo->host = host; |
774ef2d7 | 1153 | #ifdef EXPERIMENTAL_EVENT |
a7538db1 JH |
1154 | cbinfo->event_action = NULL; |
1155 | #endif | |
77bb000f | 1156 | |
059ec3d9 PH |
1157 | SSL_load_error_strings(); /* basic set up */ |
1158 | OpenSSL_add_ssl_algorithms(); | |
1159 | ||
388d6564 | 1160 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 1161 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1162 | list of available digests. */ |
1163 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1164 | #endif |
a0475b69 | 1165 | |
f0f5a555 PP |
1166 | /* Create a context. |
1167 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1168 | negotiation in the different methods; as far as I can tell, the only | |
1169 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1170 | when OpenSSL is built without SSLv2 support. | |
1171 | By disabling with openssl_options, we can let admins re-enable with the | |
1172 | existing knob. */ | |
059ec3d9 | 1173 | |
817d9f57 | 1174 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
1175 | SSLv23_server_method() : SSLv23_client_method()); |
1176 | ||
817d9f57 | 1177 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
1178 | |
1179 | /* It turns out that we need to seed the random number generator this early in | |
1180 | order to get the full complement of ciphers to work. It took me roughly a day | |
1181 | of work to discover this by experiment. | |
1182 | ||
1183 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1184 | there. Otherwise, we have to make something up as best we can. Double check | |
1185 | afterwards. */ | |
1186 | ||
1187 | if (!RAND_status()) | |
1188 | { | |
1189 | randstuff r; | |
9e3331ea | 1190 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1191 | r.p = getpid(); |
1192 | ||
1193 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1194 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1195 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1196 | ||
1197 | if (!RAND_status()) | |
7199e1ee | 1198 | return tls_error(US"RAND_status", host, |
5ca6d115 | 1199 | US"unable to seed random number generator"); |
059ec3d9 PH |
1200 | } |
1201 | ||
1202 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1203 | level. */ | |
1204 | ||
817d9f57 | 1205 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 1206 | |
c80c5570 | 1207 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 1208 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1209 | |
77bb000f PP |
1210 | /* Apply administrator-supplied work-arounds. |
1211 | Historically we applied just one requested option, | |
1212 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1213 | moved to an administrator-controlled list of options to specify and | |
1214 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1215 | |
77bb000f PP |
1216 | No OpenSSL version number checks: the options we accept depend upon the |
1217 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1218 | |
77bb000f PP |
1219 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
1220 | if (!okay) | |
73a46702 | 1221 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
1222 | |
1223 | if (init_options) | |
1224 | { | |
1225 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 1226 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
1227 | return tls_error(string_sprintf( |
1228 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1229 | } | |
1230 | else | |
1231 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
1232 | |
1233 | /* Initialize with DH parameters if supplied */ | |
1234 | ||
817d9f57 | 1235 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; |
059ec3d9 | 1236 | |
3f7eeb86 | 1237 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1238 | |
817d9f57 | 1239 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 1240 | if (rc != OK) return rc; |
c91535f3 | 1241 | |
7be682ca | 1242 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 1243 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
f5d78688 | 1244 | if (host == NULL) /* server */ |
3f0945ff | 1245 | { |
f2de3a33 | 1246 | # ifndef DISABLE_OCSP |
f5d78688 | 1247 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1248 | the option exists, not what the current expansion might be, as SNI might |
1249 | change the certificate and OCSP file in use between now and the time the | |
1250 | callback is invoked. */ | |
f5d78688 | 1251 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1252 | { |
f5d78688 | 1253 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); |
5e55c7a9 | 1254 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); |
3f7eeb86 | 1255 | } |
f5d78688 | 1256 | # endif |
3f0945ff PP |
1257 | /* We always do this, so that $tls_sni is available even if not used in |
1258 | tls_certificate */ | |
817d9f57 JH |
1259 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
1260 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 1261 | } |
f2de3a33 | 1262 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1263 | else /* client */ |
1264 | if(ocsp_file) /* wanting stapling */ | |
1265 | { | |
1266 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1267 | { | |
1268 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1269 | return FAIL; | |
1270 | } | |
1271 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1272 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1273 | } | |
1274 | # endif | |
7be682ca | 1275 | #endif |
059ec3d9 | 1276 | |
e51c7be2 JH |
1277 | #ifdef EXPERIMENTAL_CERTNAMES |
1278 | cbinfo->verify_cert_hostnames = NULL; | |
1279 | #endif | |
1280 | ||
059ec3d9 PH |
1281 | /* Set up the RSA callback */ |
1282 | ||
817d9f57 | 1283 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
1284 | |
1285 | /* Finally, set the timeout, and we are done */ | |
1286 | ||
817d9f57 | 1287 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 1288 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1289 | |
817d9f57 | 1290 | *cbp = cbinfo; |
7be682ca | 1291 | |
059ec3d9 PH |
1292 | return OK; |
1293 | } | |
1294 | ||
1295 | ||
1296 | ||
1297 | ||
1298 | /************************************************* | |
1299 | * Get name of cipher in use * | |
1300 | *************************************************/ | |
1301 | ||
817d9f57 | 1302 | /* |
059ec3d9 | 1303 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1304 | buffer to use for answer |
1305 | size of buffer | |
1306 | pointer to number of bits for cipher | |
059ec3d9 PH |
1307 | Returns: nothing |
1308 | */ | |
1309 | ||
1310 | static void | |
817d9f57 | 1311 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1312 | { |
57b3a7f5 PP |
1313 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1314 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1315 | the accessor functions use const in the prototype. */ | |
1316 | const SSL_CIPHER *c; | |
d9784128 | 1317 | const uschar *ver; |
059ec3d9 | 1318 | |
d9784128 | 1319 | ver = (const uschar *)SSL_get_version(ssl); |
059ec3d9 | 1320 | |
57b3a7f5 | 1321 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1322 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1323 | |
817d9f57 JH |
1324 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1325 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1326 | |
1327 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1328 | } | |
1329 | ||
1330 | ||
1331 | ||
1332 | ||
1333 | ||
1334 | /************************************************* | |
1335 | * Set up for verifying certificates * | |
1336 | *************************************************/ | |
1337 | ||
1338 | /* Called by both client and server startup | |
1339 | ||
1340 | Arguments: | |
7be682ca | 1341 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1342 | certs certs file or NULL |
1343 | crl CRL file or NULL | |
1344 | host NULL in a server; the remote host in a client | |
1345 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1346 | otherwise passed as FALSE | |
983207c1 | 1347 | cert_vfy_cb Callback function for certificate verification |
059ec3d9 PH |
1348 | |
1349 | Returns: OK/DEFER/FAIL | |
1350 | */ | |
1351 | ||
1352 | static int | |
983207c1 JH |
1353 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
1354 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ) | |
059ec3d9 PH |
1355 | { |
1356 | uschar *expcerts, *expcrl; | |
1357 | ||
1358 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1359 | return DEFER; | |
1360 | ||
26e72755 | 1361 | if (expcerts != NULL && *expcerts != '\0') |
059ec3d9 PH |
1362 | { |
1363 | struct stat statbuf; | |
7be682ca | 1364 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
7199e1ee | 1365 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
1366 | |
1367 | if (Ustat(expcerts, &statbuf) < 0) | |
1368 | { | |
1369 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1370 | "failed to stat %s for certificates", expcerts); | |
1371 | return DEFER; | |
1372 | } | |
1373 | else | |
1374 | { | |
1375 | uschar *file, *dir; | |
1376 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1377 | { file = NULL; dir = expcerts; } | |
1378 | else | |
1379 | { file = expcerts; dir = NULL; } | |
1380 | ||
1381 | /* If a certificate file is empty, the next function fails with an | |
1382 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1383 | certificates are recognized, but the error message is still misleading (it | |
1384 | says no certificate was supplied.) But this is better. */ | |
1385 | ||
1386 | if ((file == NULL || statbuf.st_size > 0) && | |
7be682ca | 1387 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) |
7199e1ee | 1388 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 | 1389 | |
3281c6ea | 1390 | /* Load the list of CAs for which we will accept certs, for sending |
a805c12a JH |
1391 | to the client. This is only for the one-file tls_verify_certificates |
1392 | variant. | |
1393 | If a list isn't loaded into the server, but | |
1394 | some verify locations are set, the server end appears to make | |
1395 | a wildcard reqest for client certs. | |
1396 | Meanwhile, the client library as deafult behaviour *ignores* the list | |
1397 | we send over the wire - see man SSL_CTX_set_client_cert_cb. | |
1398 | Because of this, and that the dir variant is likely only used for | |
1399 | the public-CA bundle (not for a private CA), not worth fixing. | |
1400 | */ | |
059ec3d9 PH |
1401 | if (file != NULL) |
1402 | { | |
3281c6ea JH |
1403 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); |
1404 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", | |
1405 | sk_X509_NAME_num(names)); | |
1406 | SSL_CTX_set_client_CA_list(sctx, names); | |
059ec3d9 PH |
1407 | } |
1408 | } | |
1409 | ||
1410 | /* Handle a certificate revocation list. */ | |
1411 | ||
1412 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1413 | ||
8b417f2c PH |
1414 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1415 | * merely reformatted it into the Exim code style.) | |
1416 | ||
1417 | * "From here I changed the code to add support for multiple crl's | |
1418 | * in pem format in one file or to support hashed directory entries in | |
1419 | * pem format instead of a file. This method now uses the library function | |
1420 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1421 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1422 | * itself in the verify callback." */ | |
1423 | ||
059ec3d9 PH |
1424 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1425 | if (expcrl != NULL && *expcrl != 0) | |
1426 | { | |
8b417f2c PH |
1427 | struct stat statbufcrl; |
1428 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1429 | { | |
1430 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1431 | "failed to stat %s for certificates revocation lists", expcrl); | |
1432 | return DEFER; | |
1433 | } | |
1434 | else | |
059ec3d9 | 1435 | { |
8b417f2c PH |
1436 | /* is it a file or directory? */ |
1437 | uschar *file, *dir; | |
7be682ca | 1438 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1439 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1440 | { |
8b417f2c PH |
1441 | file = NULL; |
1442 | dir = expcrl; | |
1443 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1444 | } |
1445 | else | |
1446 | { | |
8b417f2c PH |
1447 | file = expcrl; |
1448 | dir = NULL; | |
1449 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1450 | } |
8b417f2c | 1451 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1452 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1453 | |
1454 | /* setting the flags to check against the complete crl chain */ | |
1455 | ||
1456 | X509_STORE_set_flags(cvstore, | |
1457 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1458 | } |
059ec3d9 PH |
1459 | } |
1460 | ||
1461 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1462 | ||
1463 | /* If verification is optional, don't fail if no certificate */ | |
1464 | ||
7be682ca | 1465 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1466 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 1467 | cert_vfy_cb); |
059ec3d9 PH |
1468 | } |
1469 | ||
1470 | return OK; | |
1471 | } | |
1472 | ||
1473 | ||
1474 | ||
1475 | /************************************************* | |
1476 | * Start a TLS session in a server * | |
1477 | *************************************************/ | |
1478 | ||
1479 | /* This is called when Exim is running as a server, after having received | |
1480 | the STARTTLS command. It must respond to that command, and then negotiate | |
1481 | a TLS session. | |
1482 | ||
1483 | Arguments: | |
1484 | require_ciphers allowed ciphers | |
1485 | ||
1486 | Returns: OK on success | |
1487 | DEFER for errors before the start of the negotiation | |
1488 | FAIL for errors during the negotation; the server can't | |
1489 | continue running. | |
1490 | */ | |
1491 | ||
1492 | int | |
17c76198 | 1493 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1494 | { |
1495 | int rc; | |
1496 | uschar *expciphers; | |
7be682ca | 1497 | tls_ext_ctx_cb *cbinfo; |
817d9f57 | 1498 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1499 | |
1500 | /* Check for previous activation */ | |
1501 | ||
817d9f57 | 1502 | if (tls_in.active >= 0) |
059ec3d9 | 1503 | { |
5ca6d115 | 1504 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1505 | smtp_printf("554 Already in TLS\r\n"); |
1506 | return FAIL; | |
1507 | } | |
1508 | ||
1509 | /* Initialize the SSL library. If it fails, it will already have logged | |
1510 | the error. */ | |
1511 | ||
817d9f57 | 1512 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 1513 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1514 | tls_ocsp_file, |
1515 | #endif | |
817d9f57 | 1516 | NULL, &server_static_cbinfo); |
059ec3d9 | 1517 | if (rc != OK) return rc; |
817d9f57 | 1518 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1519 | |
1520 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1521 | return FAIL; | |
1522 | ||
1523 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1524 | were historically separated by underscores. So that I can use either form in my |
1525 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1526 | */ | |
059ec3d9 PH |
1527 | |
1528 | if (expciphers != NULL) | |
1529 | { | |
1530 | uschar *s = expciphers; | |
1531 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1532 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1533 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1534 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1535 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1536 | } |
1537 | ||
1538 | /* If this is a host for which certificate verification is mandatory or | |
1539 | optional, set up appropriately. */ | |
1540 | ||
817d9f57 | 1541 | tls_in.certificate_verified = FALSE; |
53a7196b JH |
1542 | #ifdef EXPERIMENTAL_DANE |
1543 | tls_in.dane_verified = FALSE; | |
1544 | #endif | |
a2ff477a | 1545 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1546 | |
1547 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1548 | { | |
983207c1 JH |
1549 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1550 | FALSE, verify_callback_server); | |
059ec3d9 | 1551 | if (rc != OK) return rc; |
a2ff477a | 1552 | server_verify_optional = FALSE; |
059ec3d9 PH |
1553 | } |
1554 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1555 | { | |
983207c1 JH |
1556 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1557 | TRUE, verify_callback_server); | |
059ec3d9 | 1558 | if (rc != OK) return rc; |
a2ff477a | 1559 | server_verify_optional = TRUE; |
059ec3d9 PH |
1560 | } |
1561 | ||
1562 | /* Prepare for new connection */ | |
1563 | ||
817d9f57 | 1564 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1565 | |
1566 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1567 | * | |
1568 | * With the SSL_clear(), we get strange interoperability bugs with | |
1569 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1570 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1571 | * | |
1572 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1573 | * session shutdown. In this case, we have a brand new object and there's no | |
1574 | * obvious reason to immediately clear it. I'm guessing that this was | |
1575 | * originally added because of incomplete initialisation which the clear fixed, | |
1576 | * in some historic release. | |
1577 | */ | |
059ec3d9 PH |
1578 | |
1579 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1580 | on connection, where outputting anything now upsets the clients and tends to | |
1581 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1582 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1583 | mode, the fflush() happens when smtp_getc() is called. */ | |
1584 | ||
817d9f57 JH |
1585 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1586 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1587 | { |
1588 | smtp_printf("220 TLS go ahead\r\n"); | |
1589 | fflush(smtp_out); | |
1590 | } | |
1591 | ||
1592 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1593 | that the OpenSSL library doesn't. */ | |
1594 | ||
817d9f57 JH |
1595 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1596 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1597 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1598 | |
1599 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1600 | ||
1601 | sigalrm_seen = FALSE; | |
1602 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1603 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1604 | alarm(0); |
1605 | ||
1606 | if (rc <= 0) | |
1607 | { | |
7199e1ee | 1608 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1609 | if (ERR_get_error() == 0) |
1610 | log_write(0, LOG_MAIN, | |
a053d125 | 1611 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1612 | return FAIL; |
1613 | } | |
1614 | ||
1615 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1616 | ||
1617 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1618 | and initialize things. */ | |
1619 | ||
817d9f57 JH |
1620 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1621 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1622 | |
1623 | DEBUG(D_tls) | |
1624 | { | |
1625 | uschar buf[2048]; | |
817d9f57 | 1626 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1627 | debug_printf("Shared ciphers: %s\n", buf); |
1628 | } | |
1629 | ||
9d1c15ef JH |
1630 | /* Record the certificate we presented */ |
1631 | { | |
1632 | X509 * crt = SSL_get_certificate(server_ssl); | |
1633 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
1634 | } | |
059ec3d9 | 1635 | |
817d9f57 JH |
1636 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1637 | Client-side (tls_out) reads (seem to?) go via | |
1638 | smtp_read_response()/ip_recv(). | |
1639 | Hence no need to duplicate for _in and _out. | |
1640 | */ | |
059ec3d9 PH |
1641 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1642 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1643 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1644 | ||
1645 | receive_getc = tls_getc; | |
1646 | receive_ungetc = tls_ungetc; | |
1647 | receive_feof = tls_feof; | |
1648 | receive_ferror = tls_ferror; | |
58eb016e | 1649 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1650 | |
817d9f57 | 1651 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1652 | return OK; |
1653 | } | |
1654 | ||
1655 | ||
1656 | ||
1657 | ||
043b1248 JH |
1658 | static int |
1659 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
1660 | host_item * host, smtp_transport_options_block * ob | |
1661 | #ifdef EXPERIMENTAL_CERTNAMES | |
1662 | , tls_ext_ctx_cb * cbinfo | |
1663 | #endif | |
1664 | ) | |
1665 | { | |
1666 | int rc; | |
1667 | /* stick to the old behaviour for compatibility if tls_verify_certificates is | |
1668 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only | |
1669 | the specified host patterns if one of them is defined */ | |
1670 | ||
1671 | if ((!ob->tls_verify_hosts && !ob->tls_try_verify_hosts) || | |
1672 | (verify_check_host(&ob->tls_verify_hosts) == OK)) | |
1673 | { | |
1674 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
1675 | ob->tls_crl, host, FALSE, verify_callback_client)) != OK) | |
1676 | return rc; | |
1677 | client_verify_optional = FALSE; | |
1678 | ||
1679 | #ifdef EXPERIMENTAL_CERTNAMES | |
1680 | if (ob->tls_verify_cert_hostnames) | |
1681 | { | |
1682 | if (!expand_check(ob->tls_verify_cert_hostnames, | |
1683 | US"tls_verify_cert_hostnames", | |
1684 | &cbinfo->verify_cert_hostnames)) | |
1685 | return FAIL; | |
1686 | if (cbinfo->verify_cert_hostnames) | |
1687 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1688 | cbinfo->verify_cert_hostnames); | |
1689 | } | |
1690 | #endif | |
1691 | } | |
1692 | else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) | |
1693 | { | |
1694 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
1695 | ob->tls_crl, host, TRUE, verify_callback_client)) != OK) | |
1696 | return rc; | |
1697 | client_verify_optional = TRUE; | |
1698 | } | |
1699 | ||
1700 | return OK; | |
1701 | } | |
059ec3d9 | 1702 | |
fde080a4 JH |
1703 | |
1704 | #ifdef EXPERIMENTAL_DANE | |
fde080a4 JH |
1705 | static int |
1706 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa) | |
1707 | { | |
1708 | dns_record * rr; | |
1709 | dns_scan dnss; | |
1710 | const char * hostnames[2] = { CS host->name, NULL }; | |
1711 | int found = 0; | |
1712 | ||
1713 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
1714 | return tls_error(US"hostnames load", host, NULL); | |
1715 | ||
1716 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); | |
1717 | rr; | |
1718 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
1719 | ) if (rr->type == T_TLSA) | |
1720 | { | |
1721 | uschar * p = rr->data; | |
1722 | uint8_t usage, selector, mtype; | |
1723 | const char * mdname; | |
1724 | ||
fde080a4 | 1725 | usage = *p++; |
133d2546 JH |
1726 | |
1727 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
1728 | if (usage != 2 && usage != 3) continue; | |
1729 | ||
fde080a4 JH |
1730 | selector = *p++; |
1731 | mtype = *p++; | |
1732 | ||
1733 | switch (mtype) | |
1734 | { | |
133d2546 JH |
1735 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
1736 | case 0: mdname = NULL; break; | |
1737 | case 1: mdname = "sha256"; break; | |
1738 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
1739 | } |
1740 | ||
133d2546 | 1741 | found++; |
fde080a4 JH |
1742 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
1743 | { | |
1744 | default: | |
1745 | case 0: /* action not taken */ | |
1746 | return tls_error(US"tlsa load", host, NULL); | |
1747 | case 1: break; | |
1748 | } | |
594706ea JH |
1749 | |
1750 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
1751 | } |
1752 | ||
1753 | if (found) | |
1754 | return OK; | |
1755 | ||
133d2546 | 1756 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
fde080a4 JH |
1757 | return FAIL; |
1758 | } | |
1759 | #endif /*EXPERIMENTAL_DANE*/ | |
1760 | ||
1761 | ||
1762 | ||
059ec3d9 PH |
1763 | /************************************************* |
1764 | * Start a TLS session in a client * | |
1765 | *************************************************/ | |
1766 | ||
1767 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1768 | ||
1769 | Argument: | |
1770 | fd the fd of the connection | |
1771 | host connected host (for messages) | |
83da1223 | 1772 | addr the first address |
a7538db1 | 1773 | tb transport (always smtp) |
0e66b3b6 | 1774 | tlsa_dnsa tlsa lookup, if DANE, else null |
059ec3d9 PH |
1775 | |
1776 | Returns: OK on success | |
1777 | FAIL otherwise - note that tls_error() will not give DEFER | |
1778 | because this is not a server | |
1779 | */ | |
1780 | ||
1781 | int | |
f5d78688 | 1782 | tls_client_start(int fd, host_item *host, address_item *addr, |
0e66b3b6 JH |
1783 | transport_instance *tb |
1784 | #ifdef EXPERIMENTAL_DANE | |
1785 | , dns_answer * tlsa_dnsa | |
1786 | #endif | |
1787 | ) | |
059ec3d9 | 1788 | { |
a7538db1 JH |
1789 | smtp_transport_options_block * ob = |
1790 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 1791 | static uschar txt[256]; |
868f5672 JH |
1792 | uschar * expciphers; |
1793 | X509 * server_cert; | |
059ec3d9 | 1794 | int rc; |
817d9f57 | 1795 | static uschar cipherbuf[256]; |
043b1248 JH |
1796 | |
1797 | #ifndef DISABLE_OCSP | |
043b1248 | 1798 | BOOL request_ocsp = FALSE; |
6634ac8d | 1799 | BOOL require_ocsp = FALSE; |
043b1248 | 1800 | #endif |
043b1248 JH |
1801 | |
1802 | #ifdef EXPERIMENTAL_DANE | |
594706ea | 1803 | tls_out.tlsa_usage = 0; |
043b1248 JH |
1804 | #endif |
1805 | ||
f2de3a33 | 1806 | #ifndef DISABLE_OCSP |
043b1248 | 1807 | { |
4f59c424 JH |
1808 | # ifdef EXPERIMENTAL_DANE |
1809 | if ( tlsa_dnsa | |
1810 | && ob->hosts_request_ocsp[0] == '*' | |
1811 | && ob->hosts_request_ocsp[1] == '\0' | |
1812 | ) | |
1813 | { | |
1814 | /* Unchanged from default. Use a safer one under DANE */ | |
1815 | request_ocsp = TRUE; | |
1816 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
1817 | " {= {4}{$tls_out_tlsa_usage}} } " | |
1818 | " {*}{}}"; | |
1819 | } | |
1820 | # endif | |
1821 | ||
fca41d5a JH |
1822 | if ((require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, |
1823 | NULL, host->name, host->address, NULL) == OK)) | |
1824 | request_ocsp = TRUE; | |
1825 | else | |
fca41d5a | 1826 | # ifdef EXPERIMENTAL_DANE |
4f59c424 | 1827 | if (!request_ocsp) |
fca41d5a JH |
1828 | # endif |
1829 | request_ocsp = verify_check_this_host(&ob->hosts_request_ocsp, | |
1830 | NULL, host->name, host->address, NULL) == OK; | |
043b1248 | 1831 | } |
f5d78688 | 1832 | #endif |
059ec3d9 | 1833 | |
65867078 JH |
1834 | rc = tls_init(&client_ctx, host, NULL, |
1835 | ob->tls_certificate, ob->tls_privatekey, | |
f2de3a33 | 1836 | #ifndef DISABLE_OCSP |
44662487 | 1837 | (void *)(long)request_ocsp, |
3f7eeb86 | 1838 | #endif |
817d9f57 | 1839 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1840 | if (rc != OK) return rc; |
1841 | ||
817d9f57 | 1842 | tls_out.certificate_verified = FALSE; |
a2ff477a | 1843 | client_verify_callback_called = FALSE; |
059ec3d9 | 1844 | |
65867078 JH |
1845 | if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", |
1846 | &expciphers)) | |
059ec3d9 PH |
1847 | return FAIL; |
1848 | ||
1849 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1850 | are separated by underscores. So that I can use either form in my tests, and | |
1851 | also for general convenience, we turn underscores into hyphens here. */ | |
1852 | ||
1853 | if (expciphers != NULL) | |
1854 | { | |
1855 | uschar *s = expciphers; | |
1856 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1857 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1858 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1859 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1860 | } |
1861 | ||
043b1248 | 1862 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 1863 | if (tlsa_dnsa) |
a63be306 | 1864 | { |
e5cccda9 JH |
1865 | SSL_CTX_set_verify(client_ctx, SSL_VERIFY_PEER, verify_callback_client_dane); |
1866 | ||
043b1248 | 1867 | if (!DANESSL_library_init()) |
b4161d10 | 1868 | return tls_error(US"library init", host, NULL); |
043b1248 | 1869 | if (DANESSL_CTX_init(client_ctx) <= 0) |
b4161d10 | 1870 | return tls_error(US"context init", host, NULL); |
043b1248 JH |
1871 | } |
1872 | else | |
e51c7be2 | 1873 | |
043b1248 JH |
1874 | #endif |
1875 | ||
1876 | if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob | |
e51c7be2 | 1877 | #ifdef EXPERIMENTAL_CERTNAMES |
043b1248 | 1878 | , client_static_cbinfo |
e51c7be2 | 1879 | #endif |
043b1248 | 1880 | )) != OK) |
65867078 | 1881 | return rc; |
059ec3d9 | 1882 | |
65867078 JH |
1883 | if ((client_ssl = SSL_new(client_ctx)) == NULL) |
1884 | return tls_error(US"SSL_new", host, NULL); | |
817d9f57 JH |
1885 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1886 | SSL_set_fd(client_ssl, fd); | |
1887 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 1888 | |
65867078 | 1889 | if (ob->tls_sni) |
3f0945ff | 1890 | { |
65867078 | 1891 | if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 1892 | return FAIL; |
ec4b68e5 | 1893 | if (tls_out.sni == NULL) |
2c9a0e86 PP |
1894 | { |
1895 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
1896 | } | |
ec4b68e5 | 1897 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 1898 | tls_out.sni = NULL; |
3f0945ff PP |
1899 | else |
1900 | { | |
35731706 | 1901 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
1902 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
1903 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
1904 | #else |
1905 | DEBUG(D_tls) | |
1906 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
02d9264f | 1907 | tls_out.sni); |
35731706 | 1908 | #endif |
3f0945ff PP |
1909 | } |
1910 | } | |
1911 | ||
594706ea | 1912 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 JH |
1913 | if (tlsa_dnsa) |
1914 | if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa)) != OK) | |
594706ea JH |
1915 | return rc; |
1916 | #endif | |
1917 | ||
f2de3a33 | 1918 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1919 | /* Request certificate status at connection-time. If the server |
1920 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
b50c8b84 | 1921 | # ifdef EXPERIMENTAL_DANE |
594706ea JH |
1922 | if (request_ocsp) |
1923 | { | |
1924 | const uschar * s; | |
41afb5cb JH |
1925 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
1926 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
1927 | ) |
1928 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
1929 | this means we avoid the OCSP request, we wasted the setup | |
1930 | cost in tls_init(). */ | |
1931 | require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, | |
1932 | NULL, host->name, host->address, NULL) == OK; | |
1933 | request_ocsp = require_ocsp ? TRUE | |
1934 | : verify_check_this_host(&ob->hosts_request_ocsp, | |
1935 | NULL, host->name, host->address, NULL) == OK; | |
1936 | } | |
1937 | } | |
b50c8b84 JH |
1938 | # endif |
1939 | ||
44662487 JH |
1940 | if (request_ocsp) |
1941 | { | |
f5d78688 | 1942 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 JH |
1943 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
1944 | tls_out.ocsp = OCSP_NOT_RESP; | |
1945 | } | |
f5d78688 JH |
1946 | #endif |
1947 | ||
774ef2d7 JH |
1948 | #ifdef EXPERIMENTAL_EVENT |
1949 | client_static_cbinfo->event_action = tb->event_action; | |
a7538db1 | 1950 | #endif |
043b1248 | 1951 | |
059ec3d9 PH |
1952 | /* There doesn't seem to be a built-in timeout on connection. */ |
1953 | ||
1954 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1955 | sigalrm_seen = FALSE; | |
65867078 | 1956 | alarm(ob->command_timeout); |
817d9f57 | 1957 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
1958 | alarm(0); |
1959 | ||
043b1248 | 1960 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 1961 | if (tlsa_dnsa) |
fde080a4 | 1962 | DANESSL_cleanup(client_ssl); |
043b1248 JH |
1963 | #endif |
1964 | ||
059ec3d9 | 1965 | if (rc <= 0) |
7199e1ee | 1966 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1967 | |
1968 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1969 | ||
453a6645 | 1970 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
9d1c15ef | 1971 | /*XXX server_cert is never freed... use X509_free() */ |
817d9f57 | 1972 | server_cert = SSL_get_peer_certificate (client_ssl); |
453a6645 PP |
1973 | if (server_cert) |
1974 | { | |
817d9f57 | 1975 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), |
453a6645 | 1976 | CS txt, sizeof(txt)); |
9d1c15ef | 1977 | tls_out.peerdn = txt; /*XXX a static buffer... */ |
453a6645 PP |
1978 | } |
1979 | else | |
817d9f57 | 1980 | tls_out.peerdn = NULL; |
059ec3d9 | 1981 | |
817d9f57 JH |
1982 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
1983 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 1984 | |
9d1c15ef JH |
1985 | /* Record the certificate we presented */ |
1986 | { | |
1987 | X509 * crt = SSL_get_certificate(client_ssl); | |
1988 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
1989 | } | |
1990 | ||
817d9f57 | 1991 | tls_out.active = fd; |
059ec3d9 PH |
1992 | return OK; |
1993 | } | |
1994 | ||
1995 | ||
1996 | ||
1997 | ||
1998 | ||
1999 | /************************************************* | |
2000 | * TLS version of getc * | |
2001 | *************************************************/ | |
2002 | ||
2003 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2004 | it refills the buffer via the SSL reading function. | |
2005 | ||
2006 | Arguments: none | |
2007 | Returns: the next character or EOF | |
817d9f57 JH |
2008 | |
2009 | Only used by the server-side TLS. | |
059ec3d9 PH |
2010 | */ |
2011 | ||
2012 | int | |
2013 | tls_getc(void) | |
2014 | { | |
2015 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
2016 | { | |
2017 | int error; | |
2018 | int inbytes; | |
2019 | ||
817d9f57 | 2020 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 2021 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
2022 | |
2023 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
2024 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
2025 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
2026 | alarm(0); |
2027 | ||
2028 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2029 | closed down, not that the socket itself has been closed down. Revert to | |
2030 | non-SSL handling. */ | |
2031 | ||
2032 | if (error == SSL_ERROR_ZERO_RETURN) | |
2033 | { | |
2034 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2035 | ||
2036 | receive_getc = smtp_getc; | |
2037 | receive_ungetc = smtp_ungetc; | |
2038 | receive_feof = smtp_feof; | |
2039 | receive_ferror = smtp_ferror; | |
58eb016e | 2040 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 2041 | |
817d9f57 JH |
2042 | SSL_free(server_ssl); |
2043 | server_ssl = NULL; | |
2044 | tls_in.active = -1; | |
2045 | tls_in.bits = 0; | |
2046 | tls_in.cipher = NULL; | |
2047 | tls_in.peerdn = NULL; | |
2048 | tls_in.sni = NULL; | |
059ec3d9 PH |
2049 | |
2050 | return smtp_getc(); | |
2051 | } | |
2052 | ||
2053 | /* Handle genuine errors */ | |
2054 | ||
ba084640 PP |
2055 | else if (error == SSL_ERROR_SSL) |
2056 | { | |
2057 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 2058 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
2059 | ssl_xfer_error = 1; |
2060 | return EOF; | |
2061 | } | |
2062 | ||
059ec3d9 PH |
2063 | else if (error != SSL_ERROR_NONE) |
2064 | { | |
2065 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2066 | ssl_xfer_error = 1; | |
2067 | return EOF; | |
2068 | } | |
c80c5570 | 2069 | |
80a47a2c TK |
2070 | #ifndef DISABLE_DKIM |
2071 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2072 | #endif | |
059ec3d9 PH |
2073 | ssl_xfer_buffer_hwm = inbytes; |
2074 | ssl_xfer_buffer_lwm = 0; | |
2075 | } | |
2076 | ||
2077 | /* Something in the buffer; return next uschar */ | |
2078 | ||
2079 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
2080 | } | |
2081 | ||
2082 | ||
2083 | ||
2084 | /************************************************* | |
2085 | * Read bytes from TLS channel * | |
2086 | *************************************************/ | |
2087 | ||
2088 | /* | |
2089 | Arguments: | |
2090 | buff buffer of data | |
2091 | len size of buffer | |
2092 | ||
2093 | Returns: the number of bytes read | |
2094 | -1 after a failed read | |
817d9f57 JH |
2095 | |
2096 | Only used by the client-side TLS. | |
059ec3d9 PH |
2097 | */ |
2098 | ||
2099 | int | |
389ca47a | 2100 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2101 | { |
389ca47a | 2102 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
2103 | int inbytes; |
2104 | int error; | |
2105 | ||
389ca47a | 2106 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2107 | buff, (unsigned int)len); |
059ec3d9 | 2108 | |
389ca47a JH |
2109 | inbytes = SSL_read(ssl, CS buff, len); |
2110 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2111 | |
2112 | if (error == SSL_ERROR_ZERO_RETURN) | |
2113 | { | |
2114 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2115 | return -1; | |
2116 | } | |
2117 | else if (error != SSL_ERROR_NONE) | |
2118 | { | |
2119 | return -1; | |
2120 | } | |
2121 | ||
2122 | return inbytes; | |
2123 | } | |
2124 | ||
2125 | ||
2126 | ||
2127 | ||
2128 | ||
2129 | /************************************************* | |
2130 | * Write bytes down TLS channel * | |
2131 | *************************************************/ | |
2132 | ||
2133 | /* | |
2134 | Arguments: | |
817d9f57 | 2135 | is_server channel specifier |
059ec3d9 PH |
2136 | buff buffer of data |
2137 | len number of bytes | |
2138 | ||
2139 | Returns: the number of bytes after a successful write, | |
2140 | -1 after a failed write | |
817d9f57 JH |
2141 | |
2142 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2143 | */ |
2144 | ||
2145 | int | |
817d9f57 | 2146 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
2147 | { |
2148 | int outbytes; | |
2149 | int error; | |
2150 | int left = len; | |
817d9f57 | 2151 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 2152 | |
c80c5570 | 2153 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
2154 | while (left > 0) |
2155 | { | |
c80c5570 | 2156 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
2157 | outbytes = SSL_write(ssl, CS buff, left); |
2158 | error = SSL_get_error(ssl, outbytes); | |
2159 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2160 | switch (error) | |
2161 | { | |
2162 | case SSL_ERROR_SSL: | |
2163 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2164 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
2165 | return -1; | |
2166 | ||
2167 | case SSL_ERROR_NONE: | |
2168 | left -= outbytes; | |
2169 | buff += outbytes; | |
2170 | break; | |
2171 | ||
2172 | case SSL_ERROR_ZERO_RETURN: | |
2173 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
2174 | return -1; | |
2175 | ||
817d9f57 JH |
2176 | case SSL_ERROR_SYSCALL: |
2177 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
2178 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
2179 | strerror(errno)); | |
2180 | ||
059ec3d9 PH |
2181 | default: |
2182 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
2183 | return -1; | |
2184 | } | |
2185 | } | |
2186 | return len; | |
2187 | } | |
2188 | ||
2189 | ||
2190 | ||
2191 | /************************************************* | |
2192 | * Close down a TLS session * | |
2193 | *************************************************/ | |
2194 | ||
2195 | /* This is also called from within a delivery subprocess forked from the | |
2196 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2197 | would tamper with the SSL session in the parent process). | |
2198 | ||
2199 | Arguments: TRUE if SSL_shutdown is to be called | |
2200 | Returns: nothing | |
817d9f57 JH |
2201 | |
2202 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2203 | */ |
2204 | ||
2205 | void | |
817d9f57 | 2206 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2207 | { |
817d9f57 | 2208 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 2209 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
2210 | |
2211 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
2212 | |
2213 | if (shutdown) | |
2214 | { | |
2215 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 2216 | SSL_shutdown(*sslp); |
059ec3d9 PH |
2217 | } |
2218 | ||
817d9f57 JH |
2219 | SSL_free(*sslp); |
2220 | *sslp = NULL; | |
059ec3d9 | 2221 | |
817d9f57 | 2222 | *fdp = -1; |
059ec3d9 PH |
2223 | } |
2224 | ||
36f12725 NM |
2225 | |
2226 | ||
2227 | ||
3375e053 PP |
2228 | /************************************************* |
2229 | * Let tls_require_ciphers be checked at startup * | |
2230 | *************************************************/ | |
2231 | ||
2232 | /* The tls_require_ciphers option, if set, must be something which the | |
2233 | library can parse. | |
2234 | ||
2235 | Returns: NULL on success, or error message | |
2236 | */ | |
2237 | ||
2238 | uschar * | |
2239 | tls_validate_require_cipher(void) | |
2240 | { | |
2241 | SSL_CTX *ctx; | |
2242 | uschar *s, *expciphers, *err; | |
2243 | ||
2244 | /* this duplicates from tls_init(), we need a better "init just global | |
2245 | state, for no specific purpose" singleton function of our own */ | |
2246 | ||
2247 | SSL_load_error_strings(); | |
2248 | OpenSSL_add_ssl_algorithms(); | |
2249 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
2250 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
2251 | list of available digests. */ | |
2252 | EVP_add_digest(EVP_sha256()); | |
2253 | #endif | |
2254 | ||
2255 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2256 | return NULL; | |
2257 | ||
2258 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2259 | return US"failed to expand tls_require_ciphers"; | |
2260 | ||
2261 | if (!(expciphers && *expciphers)) | |
2262 | return NULL; | |
2263 | ||
2264 | /* normalisation ripped from above */ | |
2265 | s = expciphers; | |
2266 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
2267 | ||
2268 | err = NULL; | |
2269 | ||
2270 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
2271 | if (!ctx) | |
2272 | { | |
2273 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2274 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
2275 | } | |
2276 | ||
2277 | DEBUG(D_tls) | |
2278 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2279 | ||
2280 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
2281 | { | |
2282 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2283 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
2284 | } | |
2285 | ||
2286 | SSL_CTX_free(ctx); | |
2287 | ||
2288 | return err; | |
2289 | } | |
2290 | ||
2291 | ||
2292 | ||
2293 | ||
36f12725 NM |
2294 | /************************************************* |
2295 | * Report the library versions. * | |
2296 | *************************************************/ | |
2297 | ||
2298 | /* There have historically been some issues with binary compatibility in | |
2299 | OpenSSL libraries; if Exim (like many other applications) is built against | |
2300 | one version of OpenSSL but the run-time linker picks up another version, | |
2301 | it can result in serious failures, including crashing with a SIGSEGV. So | |
2302 | report the version found by the compiler and the run-time version. | |
2303 | ||
f64a1e23 PP |
2304 | Note: some OS vendors backport security fixes without changing the version |
2305 | number/string, and the version date remains unchanged. The _build_ date | |
2306 | will change, so we can more usefully assist with version diagnosis by also | |
2307 | reporting the build date. | |
2308 | ||
36f12725 NM |
2309 | Arguments: a FILE* to print the results to |
2310 | Returns: nothing | |
2311 | */ | |
2312 | ||
2313 | void | |
2314 | tls_version_report(FILE *f) | |
2315 | { | |
754a0503 | 2316 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
2317 | " Runtime: %s\n" |
2318 | " : %s\n", | |
754a0503 | 2319 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
2320 | SSLeay_version(SSLEAY_VERSION), |
2321 | SSLeay_version(SSLEAY_BUILT_ON)); | |
2322 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
2323 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
2324 | } |
2325 | ||
9e3331ea TK |
2326 | |
2327 | ||
2328 | ||
2329 | /************************************************* | |
17c76198 | 2330 | * Random number generation * |
9e3331ea TK |
2331 | *************************************************/ |
2332 | ||
2333 | /* Pseudo-random number generation. The result is not expected to be | |
2334 | cryptographically strong but not so weak that someone will shoot themselves | |
2335 | in the foot using it as a nonce in input in some email header scheme or | |
2336 | whatever weirdness they'll twist this into. The result should handle fork() | |
2337 | and avoid repeating sequences. OpenSSL handles that for us. | |
2338 | ||
2339 | Arguments: | |
2340 | max range maximum | |
2341 | Returns a random number in range [0, max-1] | |
2342 | */ | |
2343 | ||
2344 | int | |
17c76198 | 2345 | vaguely_random_number(int max) |
9e3331ea TK |
2346 | { |
2347 | unsigned int r; | |
2348 | int i, needed_len; | |
de6135a0 PP |
2349 | static pid_t pidlast = 0; |
2350 | pid_t pidnow; | |
9e3331ea TK |
2351 | uschar *p; |
2352 | uschar smallbuf[sizeof(r)]; | |
2353 | ||
2354 | if (max <= 1) | |
2355 | return 0; | |
2356 | ||
de6135a0 PP |
2357 | pidnow = getpid(); |
2358 | if (pidnow != pidlast) | |
2359 | { | |
2360 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2361 | is unique for each thread", this doesn't apparently apply across processes, | |
2362 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2363 | Fix per PostgreSQL. */ | |
2364 | if (pidlast != 0) | |
2365 | RAND_cleanup(); | |
2366 | pidlast = pidnow; | |
2367 | } | |
2368 | ||
9e3331ea TK |
2369 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
2370 | if (!RAND_status()) | |
2371 | { | |
2372 | randstuff r; | |
2373 | gettimeofday(&r.tv, NULL); | |
2374 | r.p = getpid(); | |
2375 | ||
2376 | RAND_seed((uschar *)(&r), sizeof(r)); | |
2377 | } | |
2378 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2379 | in the internal PRNG then our options are limited. We could sleep and hope | |
2380 | for entropy to come along (prayer technique) but if the system is so depleted | |
2381 | in the first place then something is likely to just keep taking it. Instead, | |
2382 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2383 | get. */ | |
2384 | ||
2385 | needed_len = sizeof(r); | |
2386 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2387 | asked for a number less than 10. */ | |
2388 | for (r = max, i = 0; r; ++i) | |
2389 | r >>= 1; | |
2390 | i = (i + 7) / 8; | |
2391 | if (i < needed_len) | |
2392 | needed_len = i; | |
2393 | ||
2394 | /* We do not care if crypto-strong */ | |
17c76198 PP |
2395 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
2396 | if (i < 0) | |
2397 | { | |
2398 | DEBUG(D_all) | |
2399 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2400 | return vaguely_random_number_fallback(max); | |
2401 | } | |
2402 | ||
9e3331ea TK |
2403 | r = 0; |
2404 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2405 | { | |
2406 | r *= 256; | |
2407 | r += *p; | |
2408 | } | |
2409 | ||
2410 | /* We don't particularly care about weighted results; if someone wants | |
2411 | smooth distribution and cares enough then they should submit a patch then. */ | |
2412 | return r % max; | |
2413 | } | |
2414 | ||
77bb000f PP |
2415 | |
2416 | ||
2417 | ||
2418 | /************************************************* | |
2419 | * OpenSSL option parse * | |
2420 | *************************************************/ | |
2421 | ||
2422 | /* Parse one option for tls_openssl_options_parse below | |
2423 | ||
2424 | Arguments: | |
2425 | name one option name | |
2426 | value place to store a value for it | |
2427 | Returns success or failure in parsing | |
2428 | */ | |
2429 | ||
2430 | struct exim_openssl_option { | |
2431 | uschar *name; | |
2432 | long value; | |
2433 | }; | |
2434 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2435 | options document which version they were introduced in. Policylet: include | |
2436 | all options unless explicitly for DTLS, let the administrator choose which | |
2437 | to apply. | |
2438 | ||
2439 | This list is current as of: | |
e2fbf4a2 PP |
2440 | ==> 1.0.1b <== |
2441 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2442 | */ | |
77bb000f PP |
2443 | static struct exim_openssl_option exim_openssl_options[] = { |
2444 | /* KEEP SORTED ALPHABETICALLY! */ | |
2445 | #ifdef SSL_OP_ALL | |
73a46702 | 2446 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2447 | #endif |
2448 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2449 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2450 | #endif |
2451 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2452 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2453 | #endif |
2454 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2455 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2456 | #endif |
2457 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2458 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2459 | #endif |
2460 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2461 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2462 | #endif |
2463 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2464 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2465 | #endif |
2466 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2467 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2468 | #endif |
2469 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2470 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2471 | #endif |
2472 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2473 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2474 | #endif |
2475 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2476 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2477 | #endif |
c80c5570 PP |
2478 | #ifdef SSL_OP_NO_COMPRESSION |
2479 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2480 | #endif | |
77bb000f | 2481 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2482 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2483 | #endif |
c0c7b2da PP |
2484 | #ifdef SSL_OP_NO_SSLv2 |
2485 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2486 | #endif | |
2487 | #ifdef SSL_OP_NO_SSLv3 | |
2488 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2489 | #endif | |
2490 | #ifdef SSL_OP_NO_TICKET | |
2491 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2492 | #endif | |
2493 | #ifdef SSL_OP_NO_TLSv1 | |
2494 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2495 | #endif | |
c80c5570 PP |
2496 | #ifdef SSL_OP_NO_TLSv1_1 |
2497 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2498 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2499 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2500 | #else | |
2501 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2502 | #endif | |
2503 | #endif | |
2504 | #ifdef SSL_OP_NO_TLSv1_2 | |
2505 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2506 | #endif | |
e2fbf4a2 PP |
2507 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG |
2508 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2509 | #endif | |
77bb000f | 2510 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2511 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2512 | #endif |
2513 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2514 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2515 | #endif |
2516 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2517 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2518 | #endif |
2519 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2520 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2521 | #endif |
2522 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2523 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2524 | #endif |
2525 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2526 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2527 | #endif |
2528 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2529 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2530 | #endif |
2531 | }; | |
2532 | static int exim_openssl_options_size = | |
2533 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2534 | ||
c80c5570 | 2535 | |
77bb000f PP |
2536 | static BOOL |
2537 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2538 | { | |
2539 | int first = 0; | |
2540 | int last = exim_openssl_options_size; | |
2541 | while (last > first) | |
2542 | { | |
2543 | int middle = (first + last)/2; | |
2544 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2545 | if (c == 0) | |
2546 | { | |
2547 | *value = exim_openssl_options[middle].value; | |
2548 | return TRUE; | |
2549 | } | |
2550 | else if (c > 0) | |
2551 | first = middle + 1; | |
2552 | else | |
2553 | last = middle; | |
2554 | } | |
2555 | return FALSE; | |
2556 | } | |
2557 | ||
2558 | ||
2559 | ||
2560 | ||
2561 | /************************************************* | |
2562 | * OpenSSL option parsing logic * | |
2563 | *************************************************/ | |
2564 | ||
2565 | /* OpenSSL has a number of compatibility options which an administrator might | |
2566 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2567 | we look like log_selector. | |
2568 | ||
2569 | Arguments: | |
2570 | option_spec the administrator-supplied string of options | |
2571 | results ptr to long storage for the options bitmap | |
2572 | Returns success or failure | |
2573 | */ | |
2574 | ||
2575 | BOOL | |
2576 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2577 | { | |
2578 | long result, item; | |
2579 | uschar *s, *end; | |
2580 | uschar keep_c; | |
2581 | BOOL adding, item_parsed; | |
2582 | ||
0e944a0d | 2583 | result = 0L; |
b1770b6e | 2584 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 2585 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
2586 | #ifdef SSL_OP_NO_SSLv2 |
2587 | result |= SSL_OP_NO_SSLv2; | |
2588 | #endif | |
77bb000f PP |
2589 | |
2590 | if (option_spec == NULL) | |
2591 | { | |
2592 | *results = result; | |
2593 | return TRUE; | |
2594 | } | |
2595 | ||
2596 | for (s=option_spec; *s != '\0'; /**/) | |
2597 | { | |
2598 | while (isspace(*s)) ++s; | |
2599 | if (*s == '\0') | |
2600 | break; | |
2601 | if (*s != '+' && *s != '-') | |
2602 | { | |
2603 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 2604 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
2605 | return FALSE; |
2606 | } | |
2607 | adding = *s++ == '+'; | |
2608 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2609 | keep_c = *end; | |
2610 | *end = '\0'; | |
2611 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2612 | if (!item_parsed) | |
2613 | { | |
0e944a0d | 2614 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
2615 | return FALSE; |
2616 | } | |
2617 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2618 | adding ? "adding" : "removing", result, item, s); | |
2619 | if (adding) | |
2620 | result |= item; | |
2621 | else | |
2622 | result &= ~item; | |
2623 | *end = keep_c; | |
2624 | s = end; | |
2625 | } | |
2626 | ||
2627 | *results = result; | |
2628 | return TRUE; | |
2629 | } | |
2630 | ||
9d1c15ef JH |
2631 | /* vi: aw ai sw=2 |
2632 | */ | |
059ec3d9 | 2633 | /* End of tls-openssl.c */ |