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; | |
55414b25 | 126 | const uschar * verify_cert_hostnames; |
774ef2d7 | 127 | #ifdef EXPERIMENTAL_EVENT |
a7538db1 JH |
128 | uschar * event_action; |
129 | #endif | |
7be682ca PP |
130 | } tls_ext_ctx_cb; |
131 | ||
132 | /* should figure out a cleanup of API to handle state preserved per | |
133 | implementation, for various reasons, which can be void * in the APIs. | |
134 | For now, we hack around it. */ | |
817d9f57 JH |
135 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
136 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
137 | |
138 | static int | |
983207c1 JH |
139 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
140 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ); | |
059ec3d9 | 141 | |
3f7eeb86 | 142 | /* Callbacks */ |
3bcbbbe2 | 143 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 144 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 145 | #endif |
f2de3a33 | 146 | #ifndef DISABLE_OCSP |
f5d78688 | 147 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
148 | #endif |
149 | ||
059ec3d9 PH |
150 | |
151 | /************************************************* | |
152 | * Handle TLS error * | |
153 | *************************************************/ | |
154 | ||
155 | /* Called from lots of places when errors occur before actually starting to do | |
156 | the TLS handshake, that is, while the session is still in clear. Always returns | |
157 | DEFER for a server and FAIL for a client so that most calls can use "return | |
158 | tls_error(...)" to do this processing and then give an appropriate return. A | |
159 | single function is used for both server and client, because it is called from | |
160 | some shared functions. | |
161 | ||
162 | Argument: | |
163 | prefix text to include in the logged error | |
164 | host NULL if setting up a server; | |
165 | the connected host if setting up a client | |
7199e1ee | 166 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
167 | |
168 | Returns: OK/DEFER/FAIL | |
169 | */ | |
170 | ||
171 | static int | |
b8b1b5cb | 172 | tls_error(uschar * prefix, const host_item * host, uschar * msg) |
059ec3d9 | 173 | { |
c562fd30 | 174 | if (!msg) |
7199e1ee TF |
175 | { |
176 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 177 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
178 | } |
179 | ||
c562fd30 JH |
180 | if (host) |
181 | { | |
182 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s): %s", | |
183 | host->name, host->address, prefix, msg); | |
184 | return FAIL; | |
185 | } | |
186 | else | |
059ec3d9 | 187 | { |
7199e1ee | 188 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 189 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee | 190 | conn_info += 5; |
c562fd30 | 191 | /* I'd like to get separated H= here, but too hard for now */ |
7199e1ee TF |
192 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", |
193 | conn_info, prefix, msg); | |
059ec3d9 PH |
194 | return DEFER; |
195 | } | |
059ec3d9 PH |
196 | } |
197 | ||
198 | ||
199 | ||
200 | /************************************************* | |
201 | * Callback to generate RSA key * | |
202 | *************************************************/ | |
203 | ||
204 | /* | |
205 | Arguments: | |
206 | s SSL connection | |
207 | export not used | |
208 | keylength keylength | |
209 | ||
210 | Returns: pointer to generated key | |
211 | */ | |
212 | ||
213 | static RSA * | |
214 | rsa_callback(SSL *s, int export, int keylength) | |
215 | { | |
216 | RSA *rsa_key; | |
217 | export = export; /* Shut picky compilers up */ | |
218 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
219 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
220 | if (rsa_key == NULL) | |
221 | { | |
222 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
223 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
224 | ssl_errstring); | |
225 | return NULL; | |
226 | } | |
227 | return rsa_key; | |
228 | } | |
229 | ||
230 | ||
231 | ||
f5d78688 | 232 | /* Extreme debug |
f2de3a33 | 233 | #ifndef DISABLE_OCSP |
f5d78688 JH |
234 | void |
235 | x509_store_dump_cert_s_names(X509_STORE * store) | |
236 | { | |
237 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
238 | int i; | |
239 | static uschar name[256]; | |
240 | ||
241 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
242 | { | |
243 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
244 | if(tmp_obj->type == X509_LU_X509) | |
245 | { | |
246 | X509 * current_cert= tmp_obj->data.x509; | |
247 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
4c01d6ab | 248 | txt[sizeof(name)-1] = '\0'; |
f5d78688 JH |
249 | debug_printf(" %s\n", name); |
250 | } | |
251 | } | |
252 | } | |
253 | #endif | |
254 | */ | |
255 | ||
059ec3d9 PH |
256 | |
257 | /************************************************* | |
258 | * Callback for verification * | |
259 | *************************************************/ | |
260 | ||
261 | /* The SSL library does certificate verification if set up to do so. This | |
262 | callback has the current yes/no state is in "state". If verification succeeded, | |
263 | we set up the tls_peerdn string. If verification failed, what happens depends | |
264 | on whether the client is required to present a verifiable certificate or not. | |
265 | ||
266 | If verification is optional, we change the state to yes, but still log the | |
267 | verification error. For some reason (it really would help to have proper | |
268 | documentation of OpenSSL), this callback function then gets called again, this | |
269 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
270 | value, but we must take care not to set the private verified flag on the second | |
271 | time through. | |
272 | ||
273 | Note: this function is not called if the client fails to present a certificate | |
274 | when asked. We get here only if a certificate has been received. Handling of | |
275 | optional verification for this case is done when requesting SSL to verify, by | |
276 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
277 | ||
a7538db1 JH |
278 | May be called multiple times for different issues with a certificate, even |
279 | for a given "depth" in the certificate chain. | |
280 | ||
059ec3d9 PH |
281 | Arguments: |
282 | state current yes/no state as 1/0 | |
283 | x509ctx certificate information. | |
a2ff477a | 284 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
285 | |
286 | Returns: 1 if verified, 0 if not | |
287 | */ | |
288 | ||
289 | static int | |
421aff85 JH |
290 | verify_callback(int state, X509_STORE_CTX *x509ctx, |
291 | tls_support *tlsp, BOOL *calledp, BOOL *optionalp) | |
059ec3d9 | 292 | { |
421aff85 | 293 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 294 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
059ec3d9 | 295 | static uschar txt[256]; |
b30275b8 JH |
296 | #ifdef EXPERIMENTAL_EVENT |
297 | uschar * ev; | |
298 | uschar * yield; | |
299 | #endif | |
059ec3d9 | 300 | |
e51c7be2 | 301 | X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); |
4c01d6ab | 302 | txt[sizeof(txt)-1] = '\0'; |
059ec3d9 PH |
303 | |
304 | if (state == 0) | |
305 | { | |
4c01d6ab JH |
306 | log_write(0, LOG_MAIN, "[%s] SSL verify error: depth=%d error=%s cert=%s", |
307 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
a7538db1 | 308 | depth, |
421aff85 | 309 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), |
059ec3d9 | 310 | txt); |
a2ff477a | 311 | *calledp = TRUE; |
9d1c15ef JH |
312 | if (!*optionalp) |
313 | { | |
421aff85 | 314 | tlsp->peercert = X509_dup(cert); |
9d1c15ef JH |
315 | return 0; /* reject */ |
316 | } | |
059ec3d9 PH |
317 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
318 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
319 | } |
320 | ||
a7538db1 | 321 | else if (depth != 0) |
059ec3d9 | 322 | { |
a7538db1 | 323 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, txt); |
f2de3a33 | 324 | #ifndef DISABLE_OCSP |
f5d78688 JH |
325 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
326 | { /* client, wanting stapling */ | |
327 | /* Add the server cert's signing chain as the one | |
328 | for the verification of the OCSP stapled information. */ | |
329 | ||
330 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
421aff85 | 331 | cert)) |
f5d78688 JH |
332 | ERR_clear_error(); |
333 | } | |
a7538db1 | 334 | #endif |
774ef2d7 | 335 | #ifdef EXPERIMENTAL_EVENT |
723fe533 JH |
336 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; |
337 | if (ev) | |
a7538db1 JH |
338 | { |
339 | tlsp->peercert = X509_dup(cert); | |
b30275b8 | 340 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) |
a7538db1 | 341 | { |
4c01d6ab JH |
342 | log_write(0, LOG_MAIN, "[%s] SSL verify denied by event-action: " |
343 | "depth=%d cert=%s: %s", | |
344 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
345 | depth, txt, yield); | |
a7538db1 | 346 | *calledp = TRUE; |
a3ef7310 JH |
347 | if (!*optionalp) |
348 | return 0; /* reject */ | |
349 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
350 | "(host in tls_try_verify_hosts)\n"); | |
a7538db1 JH |
351 | } |
352 | X509_free(tlsp->peercert); | |
353 | tlsp->peercert = NULL; | |
354 | } | |
f5d78688 | 355 | #endif |
059ec3d9 PH |
356 | } |
357 | else | |
358 | { | |
55414b25 | 359 | const uschar * verify_cert_hostnames; |
e51c7be2 | 360 | |
a2ff477a | 361 | tlsp->peerdn = txt; |
421aff85 | 362 | tlsp->peercert = X509_dup(cert); |
e51c7be2 | 363 | |
e51c7be2 JH |
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 | |
8d692470 JH |
371 | # endif |
372 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
373 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
d8e7834a | 374 | # endif |
e51c7be2 JH |
375 | { |
376 | int sep = 0; | |
55414b25 | 377 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 378 | uschar * name; |
d8e7834a JH |
379 | int rc; |
380 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
381 | if ((rc = X509_check_host(cert, name, 0, | |
8d692470 JH |
382 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
383 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS))) | |
d8e7834a JH |
384 | { |
385 | if (rc < 0) | |
386 | { | |
93a6fce2 | 387 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
4c01d6ab | 388 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
389 | name = NULL; |
390 | } | |
e51c7be2 | 391 | break; |
d8e7834a | 392 | } |
e51c7be2 JH |
393 | if (!name) |
394 | { | |
395 | log_write(0, LOG_MAIN, | |
93a6fce2 | 396 | "[%s] SSL verify error: certificate name mismatch: \"%s\"", |
4c01d6ab JH |
397 | tlsp == &tls_out ? deliver_host_address : sender_host_address, |
398 | txt); | |
a3ef7310 JH |
399 | *calledp = TRUE; |
400 | if (!*optionalp) | |
401 | return 0; /* reject */ | |
402 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " | |
403 | "tls_try_verify_hosts)\n"); | |
e51c7be2 JH |
404 | } |
405 | } | |
406 | # else | |
407 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) | |
408 | { | |
409 | log_write(0, LOG_MAIN, | |
93a6fce2 | 410 | "[%s] SSL verify error: certificate name mismatch: \"%s\"", |
4c01d6ab JH |
411 | tlsp == &tls_out ? deliver_host_address : sender_host_address, |
412 | txt); | |
a3ef7310 JH |
413 | *calledp = TRUE; |
414 | if (!*optionalp) | |
415 | return 0; /* reject */ | |
416 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " | |
417 | "tls_try_verify_hosts)\n"); | |
e51c7be2 JH |
418 | } |
419 | # endif | |
e51c7be2 | 420 | |
774ef2d7 | 421 | #ifdef EXPERIMENTAL_EVENT |
723fe533 JH |
422 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; |
423 | if (ev) | |
b30275b8 | 424 | if ((yield = event_raise(ev, US"tls:cert", US"0"))) |
a7538db1 | 425 | { |
4c01d6ab JH |
426 | log_write(0, LOG_MAIN, "[%s] SSL verify denied by event-action: " |
427 | "depth=0 cert=%s: %s", | |
428 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
429 | txt, yield); | |
a7538db1 | 430 | *calledp = TRUE; |
a3ef7310 JH |
431 | if (!*optionalp) |
432 | return 0; /* reject */ | |
433 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
434 | "(host in tls_try_verify_hosts)\n"); | |
a7538db1 | 435 | } |
e51c7be2 JH |
436 | #endif |
437 | ||
93dcb1c2 JH |
438 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
439 | *calledp ? "" : " authenticated", txt); | |
440 | if (!*calledp) tlsp->certificate_verified = TRUE; | |
441 | *calledp = TRUE; | |
059ec3d9 PH |
442 | } |
443 | ||
a7538db1 | 444 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
445 | } |
446 | ||
a2ff477a JH |
447 | static int |
448 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
449 | { | |
f5d78688 | 450 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); |
a2ff477a JH |
451 | } |
452 | ||
453 | static int | |
454 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
455 | { | |
f5d78688 | 456 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); |
a2ff477a JH |
457 | } |
458 | ||
059ec3d9 | 459 | |
e5cccda9 | 460 | #ifdef EXPERIMENTAL_DANE |
53a7196b | 461 | |
e5cccda9 JH |
462 | /* This gets called *by* the dane library verify callback, which interposes |
463 | itself. | |
464 | */ | |
465 | static int | |
466 | verify_callback_client_dane(int state, X509_STORE_CTX * x509ctx) | |
467 | { | |
468 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
469 | static uschar txt[256]; | |
774ef2d7 | 470 | #ifdef EXPERIMENTAL_EVENT |
83b27293 | 471 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
b30275b8 | 472 | uschar * yield; |
83b27293 | 473 | #endif |
e5cccda9 JH |
474 | |
475 | X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); | |
4c01d6ab | 476 | txt[sizeof(txt)-1] = '\0'; |
e5cccda9 JH |
477 | |
478 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", txt); | |
479 | tls_out.peerdn = txt; | |
480 | tls_out.peercert = X509_dup(cert); | |
481 | ||
774ef2d7 | 482 | #ifdef EXPERIMENTAL_EVENT |
83b27293 JH |
483 | if (client_static_cbinfo->event_action) |
484 | { | |
b30275b8 JH |
485 | if ((yield = event_raise(client_static_cbinfo->event_action, |
486 | US"tls:cert", string_sprintf("%d", depth)))) | |
83b27293 JH |
487 | { |
488 | log_write(0, LOG_MAIN, "DANE verify denied by event-action: " | |
b30275b8 | 489 | "depth=%d cert=%s: %s", depth, txt, yield); |
83b27293 JH |
490 | tls_out.certificate_verified = FALSE; |
491 | return 0; /* reject */ | |
492 | } | |
493 | if (depth != 0) | |
494 | { | |
495 | X509_free(tls_out.peercert); | |
496 | tls_out.peercert = NULL; | |
497 | } | |
498 | } | |
499 | #endif | |
500 | ||
e5cccda9 | 501 | if (state == 1) |
53a7196b | 502 | tls_out.dane_verified = |
e5cccda9 JH |
503 | tls_out.certificate_verified = TRUE; |
504 | return 1; | |
505 | } | |
53a7196b JH |
506 | |
507 | #endif /*EXPERIMENTAL_DANE*/ | |
e5cccda9 | 508 | |
059ec3d9 PH |
509 | |
510 | /************************************************* | |
511 | * Information callback * | |
512 | *************************************************/ | |
513 | ||
514 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
515 | are doing. We copy the string to the debugging output when TLS debugging has |
516 | been requested. | |
059ec3d9 PH |
517 | |
518 | Arguments: | |
519 | s the SSL connection | |
520 | where | |
521 | ret | |
522 | ||
523 | Returns: nothing | |
524 | */ | |
525 | ||
526 | static void | |
527 | info_callback(SSL *s, int where, int ret) | |
528 | { | |
529 | where = where; | |
530 | ret = ret; | |
531 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
532 | } | |
533 | ||
534 | ||
535 | ||
536 | /************************************************* | |
537 | * Initialize for DH * | |
538 | *************************************************/ | |
539 | ||
540 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
541 | ||
542 | Arguments: | |
a799883d | 543 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 544 | host connected host, if client; NULL if server |
059ec3d9 PH |
545 | |
546 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
547 | */ | |
548 | ||
549 | static BOOL | |
b8b1b5cb | 550 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host) |
059ec3d9 | 551 | { |
059ec3d9 PH |
552 | BIO *bio; |
553 | DH *dh; | |
554 | uschar *dhexpanded; | |
a799883d | 555 | const char *pem; |
059ec3d9 PH |
556 | |
557 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
558 | return FALSE; | |
559 | ||
0df4ab80 | 560 | if (!dhexpanded || !*dhexpanded) |
a799883d | 561 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 562 | else if (dhexpanded[0] == '/') |
059ec3d9 | 563 | { |
0df4ab80 | 564 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 565 | { |
7199e1ee | 566 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
567 | host, US strerror(errno)); |
568 | return FALSE; | |
059ec3d9 | 569 | } |
a799883d PP |
570 | } |
571 | else | |
572 | { | |
573 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 574 | { |
a799883d PP |
575 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
576 | return TRUE; | |
059ec3d9 | 577 | } |
a799883d | 578 | |
0df4ab80 | 579 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
580 | { |
581 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
582 | host, US strerror(errno)); | |
583 | return FALSE; | |
584 | } | |
585 | bio = BIO_new_mem_buf(CS pem, -1); | |
586 | } | |
587 | ||
0df4ab80 | 588 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 589 | { |
059ec3d9 | 590 | BIO_free(bio); |
a799883d PP |
591 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
592 | host, NULL); | |
593 | return FALSE; | |
594 | } | |
595 | ||
596 | /* Even if it is larger, we silently return success rather than cause things | |
597 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
598 | * debatable choice. */ | |
599 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
600 | { | |
601 | DEBUG(D_tls) | |
602 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
603 | 8*DH_size(dh), tls_dh_max_bits); | |
604 | } | |
605 | else | |
606 | { | |
607 | SSL_CTX_set_tmp_dh(sctx, dh); | |
608 | DEBUG(D_tls) | |
609 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
610 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
611 | } |
612 | ||
a799883d PP |
613 | DH_free(dh); |
614 | BIO_free(bio); | |
615 | ||
616 | return TRUE; | |
059ec3d9 PH |
617 | } |
618 | ||
619 | ||
620 | ||
621 | ||
f2de3a33 | 622 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
623 | /************************************************* |
624 | * Load OCSP information into state * | |
625 | *************************************************/ | |
626 | ||
f5d78688 | 627 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
628 | caller has determined this is needed. Checks validity. Debugs a message |
629 | if invalid. | |
630 | ||
631 | ASSUMES: single response, for single cert. | |
632 | ||
633 | Arguments: | |
634 | sctx the SSL_CTX* to update | |
635 | cbinfo various parts of session state | |
636 | expanded the filename putatively holding an OCSP response | |
637 | ||
638 | */ | |
639 | ||
640 | static void | |
f5d78688 | 641 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 PP |
642 | { |
643 | BIO *bio; | |
644 | OCSP_RESPONSE *resp; | |
645 | OCSP_BASICRESP *basic_response; | |
646 | OCSP_SINGLERESP *single_response; | |
647 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
648 | X509_STORE *store; | |
649 | unsigned long verify_flags; | |
650 | int status, reason, i; | |
651 | ||
f5d78688 JH |
652 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
653 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 654 | { |
f5d78688 JH |
655 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
656 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
657 | } |
658 | ||
f5d78688 | 659 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); |
3f7eeb86 PP |
660 | if (!bio) |
661 | { | |
662 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 663 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
664 | return; |
665 | } | |
666 | ||
667 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
668 | BIO_free(bio); | |
669 | if (!resp) | |
670 | { | |
671 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
672 | return; | |
673 | } | |
674 | ||
675 | status = OCSP_response_status(resp); | |
676 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
677 | { | |
678 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
679 | OCSP_response_status_str(status), status); | |
f5d78688 | 680 | goto bad; |
3f7eeb86 PP |
681 | } |
682 | ||
683 | basic_response = OCSP_response_get1_basic(resp); | |
684 | if (!basic_response) | |
685 | { | |
686 | DEBUG(D_tls) | |
687 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 688 | goto bad; |
3f7eeb86 PP |
689 | } |
690 | ||
691 | store = SSL_CTX_get_cert_store(sctx); | |
692 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
693 | ||
694 | /* May need to expose ability to adjust those flags? | |
695 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
696 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
697 | ||
698 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
699 | if (i <= 0) | |
700 | { | |
701 | DEBUG(D_tls) { | |
702 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
703 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
704 | } |
705 | goto bad; | |
3f7eeb86 PP |
706 | } |
707 | ||
708 | /* Here's the simplifying assumption: there's only one response, for the | |
709 | one certificate we use, and nothing for anything else in a chain. If this | |
710 | proves false, we need to extract a cert id from our issued cert | |
711 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
712 | right cert in the stack and then calls OCSP_single_get0_status()). | |
713 | ||
714 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
715 | single_response = OCSP_resp_get0(basic_response, 0); | |
716 | if (!single_response) | |
717 | { | |
718 | DEBUG(D_tls) | |
719 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 720 | goto bad; |
3f7eeb86 PP |
721 | } |
722 | ||
723 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 724 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 725 | { |
f5d78688 JH |
726 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
727 | OCSP_cert_status_str(status), status, | |
728 | OCSP_crl_reason_str(reason), reason); | |
729 | goto bad; | |
3f7eeb86 PP |
730 | } |
731 | ||
732 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
733 | { | |
734 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 735 | goto bad; |
3f7eeb86 PP |
736 | } |
737 | ||
f5d78688 | 738 | supply_response: |
018058b2 | 739 | cbinfo->u_ocsp.server.response = resp; |
f5d78688 JH |
740 | return; |
741 | ||
742 | bad: | |
018058b2 JH |
743 | if (running_in_test_harness) |
744 | { | |
745 | extern char ** environ; | |
746 | uschar ** p; | |
747 | for (p = USS environ; *p != NULL; p++) | |
748 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
749 | { | |
750 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
751 | goto supply_response; | |
752 | } | |
753 | } | |
f5d78688 | 754 | return; |
3f7eeb86 | 755 | } |
f2de3a33 | 756 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
757 | |
758 | ||
759 | ||
760 | ||
7be682ca PP |
761 | /************************************************* |
762 | * Expand key and cert file specs * | |
763 | *************************************************/ | |
764 | ||
f5d78688 | 765 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
766 | new context, if Server Name Indication was used and tls_sni was seen in |
767 | the certificate string. | |
768 | ||
769 | Arguments: | |
770 | sctx the SSL_CTX* to update | |
771 | cbinfo various parts of session state | |
772 | ||
773 | Returns: OK/DEFER/FAIL | |
774 | */ | |
775 | ||
776 | static int | |
3f7eeb86 | 777 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
778 | { |
779 | uschar *expanded; | |
780 | ||
781 | if (cbinfo->certificate == NULL) | |
782 | return OK; | |
783 | ||
d9b2312b JH |
784 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
785 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
786 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
787 | ) | |
7be682ca PP |
788 | reexpand_tls_files_for_sni = TRUE; |
789 | ||
790 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
791 | return DEFER; | |
792 | ||
793 | if (expanded != NULL) | |
794 | { | |
795 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
796 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
797 | return tls_error(string_sprintf( | |
798 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
799 | cbinfo->host, NULL); | |
800 | } | |
801 | ||
802 | if (cbinfo->privatekey != NULL && | |
803 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
804 | return DEFER; | |
805 | ||
806 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
807 | of the expansion is an empty string, ignore it also, and assume the private | |
808 | key is in the same file as the certificate. */ | |
809 | ||
810 | if (expanded != NULL && *expanded != 0) | |
811 | { | |
812 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
813 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
814 | return tls_error(string_sprintf( | |
815 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
816 | } | |
817 | ||
f2de3a33 | 818 | #ifndef DISABLE_OCSP |
f5d78688 | 819 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) |
3f7eeb86 | 820 | { |
f5d78688 | 821 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) |
3f7eeb86 PP |
822 | return DEFER; |
823 | ||
824 | if (expanded != NULL && *expanded != 0) | |
825 | { | |
826 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f5d78688 JH |
827 | if (cbinfo->u_ocsp.server.file_expanded && |
828 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 PP |
829 | { |
830 | DEBUG(D_tls) | |
831 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
832 | } else { | |
833 | ocsp_load_response(sctx, cbinfo, expanded); | |
834 | } | |
835 | } | |
836 | } | |
837 | #endif | |
838 | ||
7be682ca PP |
839 | return OK; |
840 | } | |
841 | ||
842 | ||
843 | ||
844 | ||
845 | /************************************************* | |
846 | * Callback to handle SNI * | |
847 | *************************************************/ | |
848 | ||
849 | /* Called when acting as server during the TLS session setup if a Server Name | |
850 | Indication extension was sent by the client. | |
851 | ||
852 | API documentation is OpenSSL s_server.c implementation. | |
853 | ||
854 | Arguments: | |
855 | s SSL* of the current session | |
856 | ad unknown (part of OpenSSL API) (unused) | |
857 | arg Callback of "our" registered data | |
858 | ||
859 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
860 | */ | |
861 | ||
3bcbbbe2 | 862 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
863 | static int |
864 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
865 | { | |
866 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 867 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 868 | int rc; |
3f0945ff | 869 | int old_pool = store_pool; |
7be682ca PP |
870 | |
871 | if (!servername) | |
872 | return SSL_TLSEXT_ERR_OK; | |
873 | ||
3f0945ff | 874 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
875 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
876 | ||
877 | /* Make the extension value available for expansion */ | |
3f0945ff | 878 | store_pool = POOL_PERM; |
817d9f57 | 879 | tls_in.sni = string_copy(US servername); |
3f0945ff | 880 | store_pool = old_pool; |
7be682ca PP |
881 | |
882 | if (!reexpand_tls_files_for_sni) | |
883 | return SSL_TLSEXT_ERR_OK; | |
884 | ||
885 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
886 | not confident that memcpy wouldn't break some internal reference counting. | |
887 | Especially since there's a references struct member, which would be off. */ | |
888 | ||
0df4ab80 | 889 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7be682ca PP |
890 | { |
891 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
892 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
893 | return SSL_TLSEXT_ERR_NOACK; | |
894 | } | |
895 | ||
896 | /* Not sure how many of these are actually needed, since SSL object | |
897 | already exists. Might even need this selfsame callback, for reneg? */ | |
898 | ||
817d9f57 JH |
899 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
900 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
901 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
902 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
903 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
904 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
7be682ca | 905 | if (cbinfo->server_cipher_list) |
817d9f57 | 906 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
f2de3a33 | 907 | #ifndef DISABLE_OCSP |
f5d78688 | 908 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 909 | { |
f5d78688 | 910 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 911 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
912 | } |
913 | #endif | |
7be682ca | 914 | |
983207c1 | 915 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server); |
7be682ca PP |
916 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
917 | ||
3f7eeb86 PP |
918 | /* do this after setup_certs, because this can require the certs for verifying |
919 | OCSP information. */ | |
817d9f57 | 920 | rc = tls_expand_session_files(server_sni, cbinfo); |
7be682ca PP |
921 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
922 | ||
0df4ab80 JH |
923 | if (!init_dh(server_sni, cbinfo->dhparam, NULL)) |
924 | return SSL_TLSEXT_ERR_NOACK; | |
a799883d | 925 | |
7be682ca | 926 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 927 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
928 | |
929 | return SSL_TLSEXT_ERR_OK; | |
930 | } | |
3bcbbbe2 | 931 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
932 | |
933 | ||
934 | ||
935 | ||
f2de3a33 | 936 | #ifndef DISABLE_OCSP |
f5d78688 | 937 | |
3f7eeb86 PP |
938 | /************************************************* |
939 | * Callback to handle OCSP Stapling * | |
940 | *************************************************/ | |
941 | ||
942 | /* Called when acting as server during the TLS session setup if the client | |
943 | requests OCSP information with a Certificate Status Request. | |
944 | ||
945 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
946 | project. | |
947 | ||
948 | */ | |
949 | ||
950 | static int | |
f5d78688 | 951 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
952 | { |
953 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
954 | uschar *response_der; | |
955 | int response_der_len; | |
956 | ||
af4a1bca JH |
957 | DEBUG(D_tls) |
958 | debug_printf("Received TLS status request (OCSP stapling); %s response.", | |
f5d78688 JH |
959 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
960 | ||
44662487 | 961 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 962 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
963 | return SSL_TLSEXT_ERR_NOACK; |
964 | ||
965 | response_der = NULL; | |
44662487 JH |
966 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, |
967 | &response_der); | |
3f7eeb86 PP |
968 | if (response_der_len <= 0) |
969 | return SSL_TLSEXT_ERR_NOACK; | |
970 | ||
5e55c7a9 | 971 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 972 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
973 | return SSL_TLSEXT_ERR_OK; |
974 | } | |
975 | ||
3f7eeb86 | 976 | |
f5d78688 JH |
977 | static void |
978 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
979 | { | |
980 | BIO_printf(bp, "\t%s: ", str); | |
981 | ASN1_GENERALIZEDTIME_print(bp, time); | |
982 | BIO_puts(bp, "\n"); | |
983 | } | |
984 | ||
985 | static int | |
986 | tls_client_stapling_cb(SSL *s, void *arg) | |
987 | { | |
988 | tls_ext_ctx_cb * cbinfo = arg; | |
989 | const unsigned char * p; | |
990 | int len; | |
991 | OCSP_RESPONSE * rsp; | |
992 | OCSP_BASICRESP * bs; | |
993 | int i; | |
994 | ||
995 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
996 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
997 | if(!p) | |
998 | { | |
44662487 JH |
999 | /* Expect this when we requested ocsp but got none */ |
1000 | if ( cbinfo->u_ocsp.client.verify_required | |
1001 | && log_extra_selector & LX_tls_cipher) | |
1002 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); | |
f5d78688 JH |
1003 | else |
1004 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1005 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1006 | } |
018058b2 | 1007 | |
f5d78688 JH |
1008 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
1009 | { | |
018058b2 | 1010 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 | 1011 | if (log_extra_selector & LX_tls_cipher) |
1eca31ca | 1012 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
1013 | else |
1014 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1015 | return 0; | |
1016 | } | |
1017 | ||
1018 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
1019 | { | |
018058b2 | 1020 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 | 1021 | if (log_extra_selector & LX_tls_cipher) |
1eca31ca | 1022 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1023 | else |
1024 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1025 | OCSP_RESPONSE_free(rsp); | |
1026 | return 0; | |
1027 | } | |
1028 | ||
1029 | /* We'd check the nonce here if we'd put one in the request. */ | |
1030 | /* However that would defeat cacheability on the server so we don't. */ | |
1031 | ||
f5d78688 JH |
1032 | /* This section of code reworked from OpenSSL apps source; |
1033 | The OpenSSL Project retains copyright: | |
1034 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1035 | */ | |
1036 | { | |
1037 | BIO * bp = NULL; | |
f5d78688 JH |
1038 | int status, reason; |
1039 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1040 | ||
1041 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
1042 | ||
1043 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1044 | ||
1045 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1046 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1047 | ||
44662487 JH |
1048 | if ((i = OCSP_basic_verify(bs, NULL, |
1049 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
f5d78688 | 1050 | { |
018058b2 | 1051 | tls_out.ocsp = OCSP_FAILED; |
1eca31ca JH |
1052 | if (log_extra_selector & LX_tls_cipher) |
1053 | log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable"); | |
f5d78688 JH |
1054 | BIO_printf(bp, "OCSP response verify failure\n"); |
1055 | ERR_print_errors(bp); | |
44662487 | 1056 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 JH |
1057 | goto out; |
1058 | } | |
1059 | ||
1060 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1061 | ||
1062 | { | |
1063 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
1064 | OCSP_SINGLERESP * single; | |
1065 | ||
1066 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
1067 | { | |
018058b2 | 1068 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1069 | log_write(0, LOG_MAIN, "OCSP stapling " |
1070 | "with multiple responses not handled"); | |
1071 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
f5d78688 JH |
1072 | goto out; |
1073 | } | |
1074 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1075 | status = OCSP_single_get0_status(single, &reason, &rev, |
1076 | &thisupd, &nextupd); | |
f5d78688 JH |
1077 | } |
1078 | ||
f5d78688 JH |
1079 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1080 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1081 | if (!OCSP_check_validity(thisupd, nextupd, |
1082 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1083 | { |
018058b2 | 1084 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1085 | DEBUG(D_tls) ERR_print_errors(bp); |
1086 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
44662487 | 1087 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1088 | } |
44662487 | 1089 | else |
f5d78688 | 1090 | { |
44662487 JH |
1091 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1092 | OCSP_cert_status_str(status)); | |
1093 | switch(status) | |
1094 | { | |
1095 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1096 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1097 | i = 1; |
44662487 JH |
1098 | break; |
1099 | case V_OCSP_CERTSTATUS_REVOKED: | |
018058b2 | 1100 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1101 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1102 | reason != -1 ? "; reason: " : "", | |
1103 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1104 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
1105 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1106 | break; | |
1107 | default: | |
018058b2 | 1108 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1109 | log_write(0, LOG_MAIN, |
1110 | "Server certificate status unknown, in OCSP stapling"); | |
1111 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1112 | break; | |
1113 | } | |
f5d78688 JH |
1114 | } |
1115 | out: | |
1116 | BIO_free(bp); | |
1117 | } | |
1118 | ||
1119 | OCSP_RESPONSE_free(rsp); | |
1120 | return i; | |
1121 | } | |
f2de3a33 | 1122 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1123 | |
1124 | ||
059ec3d9 PH |
1125 | /************************************************* |
1126 | * Initialize for TLS * | |
1127 | *************************************************/ | |
1128 | ||
e51c7be2 JH |
1129 | /* Called from both server and client code, to do preliminary initialization |
1130 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1131 | |
1132 | Arguments: | |
946ecbe0 | 1133 | ctxp returned SSL context |
059ec3d9 PH |
1134 | host connected host, if client; NULL if server |
1135 | dhparam DH parameter file | |
1136 | certificate certificate file | |
1137 | privatekey private key | |
f5d78688 | 1138 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1139 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1140 | cbp place to put allocated callback context |
059ec3d9 PH |
1141 | |
1142 | Returns: OK/DEFER/FAIL | |
1143 | */ | |
1144 | ||
1145 | static int | |
817d9f57 | 1146 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1147 | uschar *privatekey, |
f2de3a33 | 1148 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1149 | uschar *ocsp_file, |
1150 | #endif | |
817d9f57 | 1151 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 1152 | { |
77bb000f | 1153 | long init_options; |
7be682ca | 1154 | int rc; |
77bb000f | 1155 | BOOL okay; |
a7538db1 | 1156 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1157 | |
1158 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1159 | cbinfo->certificate = certificate; | |
1160 | cbinfo->privatekey = privatekey; | |
f2de3a33 | 1161 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1162 | if ((cbinfo->is_server = host==NULL)) |
1163 | { | |
1164 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1165 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1166 | cbinfo->u_ocsp.server.response = NULL; | |
1167 | } | |
1168 | else | |
1169 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1170 | #endif |
7be682ca | 1171 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1172 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1173 | cbinfo->host = host; |
774ef2d7 | 1174 | #ifdef EXPERIMENTAL_EVENT |
a7538db1 JH |
1175 | cbinfo->event_action = NULL; |
1176 | #endif | |
77bb000f | 1177 | |
059ec3d9 PH |
1178 | SSL_load_error_strings(); /* basic set up */ |
1179 | OpenSSL_add_ssl_algorithms(); | |
1180 | ||
388d6564 | 1181 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 1182 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1183 | list of available digests. */ |
1184 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1185 | #endif |
a0475b69 | 1186 | |
f0f5a555 PP |
1187 | /* Create a context. |
1188 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1189 | negotiation in the different methods; as far as I can tell, the only | |
1190 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1191 | when OpenSSL is built without SSLv2 support. | |
1192 | By disabling with openssl_options, we can let admins re-enable with the | |
1193 | existing knob. */ | |
059ec3d9 | 1194 | |
817d9f57 | 1195 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
1196 | SSLv23_server_method() : SSLv23_client_method()); |
1197 | ||
817d9f57 | 1198 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
1199 | |
1200 | /* It turns out that we need to seed the random number generator this early in | |
1201 | order to get the full complement of ciphers to work. It took me roughly a day | |
1202 | of work to discover this by experiment. | |
1203 | ||
1204 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1205 | there. Otherwise, we have to make something up as best we can. Double check | |
1206 | afterwards. */ | |
1207 | ||
1208 | if (!RAND_status()) | |
1209 | { | |
1210 | randstuff r; | |
9e3331ea | 1211 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1212 | r.p = getpid(); |
1213 | ||
1214 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1215 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1216 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1217 | ||
1218 | if (!RAND_status()) | |
7199e1ee | 1219 | return tls_error(US"RAND_status", host, |
5ca6d115 | 1220 | US"unable to seed random number generator"); |
059ec3d9 PH |
1221 | } |
1222 | ||
1223 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1224 | level. */ | |
1225 | ||
817d9f57 | 1226 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 1227 | |
c80c5570 | 1228 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 1229 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1230 | |
77bb000f PP |
1231 | /* Apply administrator-supplied work-arounds. |
1232 | Historically we applied just one requested option, | |
1233 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1234 | moved to an administrator-controlled list of options to specify and | |
1235 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1236 | |
77bb000f PP |
1237 | No OpenSSL version number checks: the options we accept depend upon the |
1238 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1239 | |
77bb000f PP |
1240 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
1241 | if (!okay) | |
73a46702 | 1242 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
1243 | |
1244 | if (init_options) | |
1245 | { | |
1246 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 1247 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
1248 | return tls_error(string_sprintf( |
1249 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1250 | } | |
1251 | else | |
1252 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
1253 | |
1254 | /* Initialize with DH parameters if supplied */ | |
1255 | ||
817d9f57 | 1256 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; |
059ec3d9 | 1257 | |
3f7eeb86 | 1258 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1259 | |
817d9f57 | 1260 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 1261 | if (rc != OK) return rc; |
c91535f3 | 1262 | |
7be682ca | 1263 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 1264 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
f5d78688 | 1265 | if (host == NULL) /* server */ |
3f0945ff | 1266 | { |
f2de3a33 | 1267 | # ifndef DISABLE_OCSP |
f5d78688 | 1268 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1269 | the option exists, not what the current expansion might be, as SNI might |
1270 | change the certificate and OCSP file in use between now and the time the | |
1271 | callback is invoked. */ | |
f5d78688 | 1272 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1273 | { |
f5d78688 | 1274 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); |
5e55c7a9 | 1275 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); |
3f7eeb86 | 1276 | } |
f5d78688 | 1277 | # endif |
3f0945ff PP |
1278 | /* We always do this, so that $tls_sni is available even if not used in |
1279 | tls_certificate */ | |
817d9f57 JH |
1280 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
1281 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 1282 | } |
f2de3a33 | 1283 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1284 | else /* client */ |
1285 | if(ocsp_file) /* wanting stapling */ | |
1286 | { | |
1287 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1288 | { | |
1289 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1290 | return FAIL; | |
1291 | } | |
1292 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1293 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1294 | } | |
1295 | # endif | |
7be682ca | 1296 | #endif |
059ec3d9 | 1297 | |
e51c7be2 | 1298 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 1299 | |
059ec3d9 PH |
1300 | /* Set up the RSA callback */ |
1301 | ||
817d9f57 | 1302 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
1303 | |
1304 | /* Finally, set the timeout, and we are done */ | |
1305 | ||
817d9f57 | 1306 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 1307 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1308 | |
817d9f57 | 1309 | *cbp = cbinfo; |
7be682ca | 1310 | |
059ec3d9 PH |
1311 | return OK; |
1312 | } | |
1313 | ||
1314 | ||
1315 | ||
1316 | ||
1317 | /************************************************* | |
1318 | * Get name of cipher in use * | |
1319 | *************************************************/ | |
1320 | ||
817d9f57 | 1321 | /* |
059ec3d9 | 1322 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1323 | buffer to use for answer |
1324 | size of buffer | |
1325 | pointer to number of bits for cipher | |
059ec3d9 PH |
1326 | Returns: nothing |
1327 | */ | |
1328 | ||
1329 | static void | |
817d9f57 | 1330 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1331 | { |
57b3a7f5 PP |
1332 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1333 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1334 | the accessor functions use const in the prototype. */ | |
1335 | const SSL_CIPHER *c; | |
d9784128 | 1336 | const uschar *ver; |
059ec3d9 | 1337 | |
d9784128 | 1338 | ver = (const uschar *)SSL_get_version(ssl); |
059ec3d9 | 1339 | |
57b3a7f5 | 1340 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1341 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1342 | |
817d9f57 JH |
1343 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1344 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1345 | |
1346 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1347 | } | |
1348 | ||
1349 | ||
1350 | ||
1351 | ||
1352 | ||
1353 | /************************************************* | |
1354 | * Set up for verifying certificates * | |
1355 | *************************************************/ | |
1356 | ||
1357 | /* Called by both client and server startup | |
1358 | ||
1359 | Arguments: | |
7be682ca | 1360 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1361 | certs certs file or NULL |
1362 | crl CRL file or NULL | |
1363 | host NULL in a server; the remote host in a client | |
1364 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1365 | otherwise passed as FALSE | |
983207c1 | 1366 | cert_vfy_cb Callback function for certificate verification |
059ec3d9 PH |
1367 | |
1368 | Returns: OK/DEFER/FAIL | |
1369 | */ | |
1370 | ||
1371 | static int | |
983207c1 JH |
1372 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
1373 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ) | |
059ec3d9 PH |
1374 | { |
1375 | uschar *expcerts, *expcrl; | |
1376 | ||
1377 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1378 | return DEFER; | |
1379 | ||
26e72755 | 1380 | if (expcerts != NULL && *expcerts != '\0') |
059ec3d9 | 1381 | { |
cb1d7830 | 1382 | if (Ustrcmp(expcerts, "system") == 0) |
059ec3d9 | 1383 | { |
cb1d7830 JH |
1384 | /* Tell the library to use its compiled-in location for the system default |
1385 | CA bundle, only */ | |
1386 | ||
1387 | if (!SSL_CTX_set_default_verify_paths(sctx)) | |
1388 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); | |
059ec3d9 PH |
1389 | } |
1390 | else | |
1391 | { | |
cb1d7830 JH |
1392 | struct stat statbuf; |
1393 | ||
1394 | /* Tell the library to use its compiled-in location for the system default | |
1395 | CA bundle. Those given by the exim config are additional to these */ | |
1396 | ||
1397 | if (!SSL_CTX_set_default_verify_paths(sctx)) | |
1398 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); | |
1399 | ||
1400 | if (Ustat(expcerts, &statbuf) < 0) | |
1401 | { | |
1402 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1403 | "failed to stat %s for certificates", expcerts); | |
1404 | return DEFER; | |
1405 | } | |
059ec3d9 | 1406 | else |
059ec3d9 | 1407 | { |
cb1d7830 JH |
1408 | uschar *file, *dir; |
1409 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1410 | { file = NULL; dir = expcerts; } | |
1411 | else | |
1412 | { file = expcerts; dir = NULL; } | |
1413 | ||
1414 | /* If a certificate file is empty, the next function fails with an | |
1415 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1416 | certificates are recognized, but the error message is still misleading (it | |
1417 | says no certificate was supplied.) But this is better. */ | |
1418 | ||
1419 | if ((file == NULL || statbuf.st_size > 0) && | |
1420 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
1421 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); | |
1422 | ||
1423 | /* Load the list of CAs for which we will accept certs, for sending | |
1424 | to the client. This is only for the one-file tls_verify_certificates | |
1425 | variant. | |
1426 | If a list isn't loaded into the server, but | |
1427 | some verify locations are set, the server end appears to make | |
1428 | a wildcard reqest for client certs. | |
1429 | Meanwhile, the client library as deafult behaviour *ignores* the list | |
1430 | we send over the wire - see man SSL_CTX_set_client_cert_cb. | |
1431 | Because of this, and that the dir variant is likely only used for | |
1432 | the public-CA bundle (not for a private CA), not worth fixing. | |
1433 | */ | |
1434 | if (file != NULL) | |
1435 | { | |
1436 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); | |
1437 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", | |
1438 | sk_X509_NAME_num(names)); | |
1439 | SSL_CTX_set_client_CA_list(sctx, names); | |
1440 | } | |
059ec3d9 PH |
1441 | } |
1442 | } | |
1443 | ||
1444 | /* Handle a certificate revocation list. */ | |
1445 | ||
1446 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1447 | ||
8b417f2c PH |
1448 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1449 | * merely reformatted it into the Exim code style.) | |
1450 | ||
1451 | * "From here I changed the code to add support for multiple crl's | |
1452 | * in pem format in one file or to support hashed directory entries in | |
1453 | * pem format instead of a file. This method now uses the library function | |
1454 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1455 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1456 | * itself in the verify callback." */ | |
1457 | ||
059ec3d9 PH |
1458 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1459 | if (expcrl != NULL && *expcrl != 0) | |
1460 | { | |
8b417f2c PH |
1461 | struct stat statbufcrl; |
1462 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1463 | { | |
1464 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1465 | "failed to stat %s for certificates revocation lists", expcrl); | |
1466 | return DEFER; | |
1467 | } | |
1468 | else | |
059ec3d9 | 1469 | { |
8b417f2c PH |
1470 | /* is it a file or directory? */ |
1471 | uschar *file, *dir; | |
7be682ca | 1472 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1473 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1474 | { |
8b417f2c PH |
1475 | file = NULL; |
1476 | dir = expcrl; | |
1477 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1478 | } |
1479 | else | |
1480 | { | |
8b417f2c PH |
1481 | file = expcrl; |
1482 | dir = NULL; | |
1483 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1484 | } |
8b417f2c | 1485 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1486 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1487 | |
1488 | /* setting the flags to check against the complete crl chain */ | |
1489 | ||
1490 | X509_STORE_set_flags(cvstore, | |
1491 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1492 | } |
059ec3d9 PH |
1493 | } |
1494 | ||
1495 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1496 | ||
1497 | /* If verification is optional, don't fail if no certificate */ | |
1498 | ||
7be682ca | 1499 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1500 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 1501 | cert_vfy_cb); |
059ec3d9 PH |
1502 | } |
1503 | ||
1504 | return OK; | |
1505 | } | |
1506 | ||
1507 | ||
1508 | ||
1509 | /************************************************* | |
1510 | * Start a TLS session in a server * | |
1511 | *************************************************/ | |
1512 | ||
1513 | /* This is called when Exim is running as a server, after having received | |
1514 | the STARTTLS command. It must respond to that command, and then negotiate | |
1515 | a TLS session. | |
1516 | ||
1517 | Arguments: | |
1518 | require_ciphers allowed ciphers | |
1519 | ||
1520 | Returns: OK on success | |
1521 | DEFER for errors before the start of the negotiation | |
1522 | FAIL for errors during the negotation; the server can't | |
1523 | continue running. | |
1524 | */ | |
1525 | ||
1526 | int | |
17c76198 | 1527 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1528 | { |
1529 | int rc; | |
1530 | uschar *expciphers; | |
7be682ca | 1531 | tls_ext_ctx_cb *cbinfo; |
817d9f57 | 1532 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1533 | |
1534 | /* Check for previous activation */ | |
1535 | ||
817d9f57 | 1536 | if (tls_in.active >= 0) |
059ec3d9 | 1537 | { |
5ca6d115 | 1538 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1539 | smtp_printf("554 Already in TLS\r\n"); |
1540 | return FAIL; | |
1541 | } | |
1542 | ||
1543 | /* Initialize the SSL library. If it fails, it will already have logged | |
1544 | the error. */ | |
1545 | ||
817d9f57 | 1546 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 1547 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1548 | tls_ocsp_file, |
1549 | #endif | |
817d9f57 | 1550 | NULL, &server_static_cbinfo); |
059ec3d9 | 1551 | if (rc != OK) return rc; |
817d9f57 | 1552 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1553 | |
1554 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1555 | return FAIL; | |
1556 | ||
1557 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1558 | were historically separated by underscores. So that I can use either form in my |
1559 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1560 | */ | |
059ec3d9 PH |
1561 | |
1562 | if (expciphers != NULL) | |
1563 | { | |
1564 | uschar *s = expciphers; | |
1565 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1566 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1567 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1568 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1569 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1570 | } |
1571 | ||
1572 | /* If this is a host for which certificate verification is mandatory or | |
1573 | optional, set up appropriately. */ | |
1574 | ||
817d9f57 | 1575 | tls_in.certificate_verified = FALSE; |
53a7196b JH |
1576 | #ifdef EXPERIMENTAL_DANE |
1577 | tls_in.dane_verified = FALSE; | |
1578 | #endif | |
a2ff477a | 1579 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1580 | |
1581 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1582 | { | |
983207c1 JH |
1583 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1584 | FALSE, verify_callback_server); | |
059ec3d9 | 1585 | if (rc != OK) return rc; |
a2ff477a | 1586 | server_verify_optional = FALSE; |
059ec3d9 PH |
1587 | } |
1588 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1589 | { | |
983207c1 JH |
1590 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1591 | TRUE, verify_callback_server); | |
059ec3d9 | 1592 | if (rc != OK) return rc; |
a2ff477a | 1593 | server_verify_optional = TRUE; |
059ec3d9 PH |
1594 | } |
1595 | ||
1596 | /* Prepare for new connection */ | |
1597 | ||
817d9f57 | 1598 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1599 | |
1600 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1601 | * | |
1602 | * With the SSL_clear(), we get strange interoperability bugs with | |
1603 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1604 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1605 | * | |
1606 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1607 | * session shutdown. In this case, we have a brand new object and there's no | |
1608 | * obvious reason to immediately clear it. I'm guessing that this was | |
1609 | * originally added because of incomplete initialisation which the clear fixed, | |
1610 | * in some historic release. | |
1611 | */ | |
059ec3d9 PH |
1612 | |
1613 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1614 | on connection, where outputting anything now upsets the clients and tends to | |
1615 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1616 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1617 | mode, the fflush() happens when smtp_getc() is called. */ | |
1618 | ||
817d9f57 JH |
1619 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1620 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1621 | { |
1622 | smtp_printf("220 TLS go ahead\r\n"); | |
1623 | fflush(smtp_out); | |
1624 | } | |
1625 | ||
1626 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1627 | that the OpenSSL library doesn't. */ | |
1628 | ||
817d9f57 JH |
1629 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1630 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1631 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1632 | |
1633 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1634 | ||
1635 | sigalrm_seen = FALSE; | |
1636 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1637 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1638 | alarm(0); |
1639 | ||
1640 | if (rc <= 0) | |
1641 | { | |
7199e1ee | 1642 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1643 | if (ERR_get_error() == 0) |
1644 | log_write(0, LOG_MAIN, | |
a053d125 | 1645 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1646 | return FAIL; |
1647 | } | |
1648 | ||
1649 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1650 | ||
1651 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1652 | and initialize things. */ | |
1653 | ||
817d9f57 JH |
1654 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1655 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1656 | |
1657 | DEBUG(D_tls) | |
1658 | { | |
1659 | uschar buf[2048]; | |
817d9f57 | 1660 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1661 | debug_printf("Shared ciphers: %s\n", buf); |
1662 | } | |
1663 | ||
9d1c15ef JH |
1664 | /* Record the certificate we presented */ |
1665 | { | |
1666 | X509 * crt = SSL_get_certificate(server_ssl); | |
1667 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
1668 | } | |
059ec3d9 | 1669 | |
817d9f57 JH |
1670 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1671 | Client-side (tls_out) reads (seem to?) go via | |
1672 | smtp_read_response()/ip_recv(). | |
1673 | Hence no need to duplicate for _in and _out. | |
1674 | */ | |
059ec3d9 PH |
1675 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1676 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1677 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1678 | ||
1679 | receive_getc = tls_getc; | |
1680 | receive_ungetc = tls_ungetc; | |
1681 | receive_feof = tls_feof; | |
1682 | receive_ferror = tls_ferror; | |
58eb016e | 1683 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1684 | |
817d9f57 | 1685 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1686 | return OK; |
1687 | } | |
1688 | ||
1689 | ||
1690 | ||
1691 | ||
043b1248 JH |
1692 | static int |
1693 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
01a4a5c5 | 1694 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo |
043b1248 JH |
1695 | ) |
1696 | { | |
1697 | int rc; | |
1698 | /* stick to the old behaviour for compatibility if tls_verify_certificates is | |
1699 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only | |
1700 | the specified host patterns if one of them is defined */ | |
1701 | ||
610ff438 JH |
1702 | if ( ( !ob->tls_verify_hosts |
1703 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
1704 | ) | |
5130845b | 1705 | || (verify_check_given_host(&ob->tls_verify_hosts, host) == OK) |
aa2a70ba | 1706 | ) |
043b1248 | 1707 | client_verify_optional = FALSE; |
5130845b | 1708 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
1709 | client_verify_optional = TRUE; |
1710 | else | |
1711 | return OK; | |
1712 | ||
1713 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
1714 | ob->tls_crl, host, client_verify_optional, verify_callback_client)) != OK) | |
1715 | return rc; | |
043b1248 | 1716 | |
5130845b | 1717 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 1718 | { |
aa2a70ba JH |
1719 | cbinfo->verify_cert_hostnames = host->name; |
1720 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1721 | cbinfo->verify_cert_hostnames); | |
043b1248 | 1722 | } |
043b1248 JH |
1723 | return OK; |
1724 | } | |
059ec3d9 | 1725 | |
fde080a4 JH |
1726 | |
1727 | #ifdef EXPERIMENTAL_DANE | |
fde080a4 JH |
1728 | static int |
1729 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa) | |
1730 | { | |
1731 | dns_record * rr; | |
1732 | dns_scan dnss; | |
1733 | const char * hostnames[2] = { CS host->name, NULL }; | |
1734 | int found = 0; | |
1735 | ||
1736 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
1737 | return tls_error(US"hostnames load", host, NULL); | |
1738 | ||
1739 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); | |
1740 | rr; | |
1741 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
1742 | ) if (rr->type == T_TLSA) | |
1743 | { | |
1744 | uschar * p = rr->data; | |
1745 | uint8_t usage, selector, mtype; | |
1746 | const char * mdname; | |
1747 | ||
fde080a4 | 1748 | usage = *p++; |
133d2546 JH |
1749 | |
1750 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
1751 | if (usage != 2 && usage != 3) continue; | |
1752 | ||
fde080a4 JH |
1753 | selector = *p++; |
1754 | mtype = *p++; | |
1755 | ||
1756 | switch (mtype) | |
1757 | { | |
133d2546 JH |
1758 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
1759 | case 0: mdname = NULL; break; | |
1760 | case 1: mdname = "sha256"; break; | |
1761 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
1762 | } |
1763 | ||
133d2546 | 1764 | found++; |
fde080a4 JH |
1765 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
1766 | { | |
1767 | default: | |
1768 | case 0: /* action not taken */ | |
1769 | return tls_error(US"tlsa load", host, NULL); | |
1770 | case 1: break; | |
1771 | } | |
594706ea JH |
1772 | |
1773 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
1774 | } |
1775 | ||
1776 | if (found) | |
1777 | return OK; | |
1778 | ||
133d2546 | 1779 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 1780 | return DEFER; |
fde080a4 JH |
1781 | } |
1782 | #endif /*EXPERIMENTAL_DANE*/ | |
1783 | ||
1784 | ||
1785 | ||
059ec3d9 PH |
1786 | /************************************************* |
1787 | * Start a TLS session in a client * | |
1788 | *************************************************/ | |
1789 | ||
1790 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1791 | ||
1792 | Argument: | |
1793 | fd the fd of the connection | |
1794 | host connected host (for messages) | |
83da1223 | 1795 | addr the first address |
a7538db1 | 1796 | tb transport (always smtp) |
0e66b3b6 | 1797 | tlsa_dnsa tlsa lookup, if DANE, else null |
059ec3d9 PH |
1798 | |
1799 | Returns: OK on success | |
1800 | FAIL otherwise - note that tls_error() will not give DEFER | |
1801 | because this is not a server | |
1802 | */ | |
1803 | ||
1804 | int | |
f5d78688 | 1805 | tls_client_start(int fd, host_item *host, address_item *addr, |
0e66b3b6 JH |
1806 | transport_instance *tb |
1807 | #ifdef EXPERIMENTAL_DANE | |
1808 | , dns_answer * tlsa_dnsa | |
1809 | #endif | |
1810 | ) | |
059ec3d9 | 1811 | { |
a7538db1 JH |
1812 | smtp_transport_options_block * ob = |
1813 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 1814 | static uschar txt[256]; |
868f5672 JH |
1815 | uschar * expciphers; |
1816 | X509 * server_cert; | |
059ec3d9 | 1817 | int rc; |
817d9f57 | 1818 | static uschar cipherbuf[256]; |
043b1248 JH |
1819 | |
1820 | #ifndef DISABLE_OCSP | |
043b1248 | 1821 | BOOL request_ocsp = FALSE; |
6634ac8d | 1822 | BOOL require_ocsp = FALSE; |
043b1248 | 1823 | #endif |
043b1248 JH |
1824 | |
1825 | #ifdef EXPERIMENTAL_DANE | |
594706ea | 1826 | tls_out.tlsa_usage = 0; |
043b1248 JH |
1827 | #endif |
1828 | ||
f2de3a33 | 1829 | #ifndef DISABLE_OCSP |
043b1248 | 1830 | { |
4f59c424 JH |
1831 | # ifdef EXPERIMENTAL_DANE |
1832 | if ( tlsa_dnsa | |
1833 | && ob->hosts_request_ocsp[0] == '*' | |
1834 | && ob->hosts_request_ocsp[1] == '\0' | |
1835 | ) | |
1836 | { | |
1837 | /* Unchanged from default. Use a safer one under DANE */ | |
1838 | request_ocsp = TRUE; | |
1839 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
1840 | " {= {4}{$tls_out_tlsa_usage}} } " | |
1841 | " {*}{}}"; | |
1842 | } | |
1843 | # endif | |
1844 | ||
5130845b JH |
1845 | if ((require_ocsp = |
1846 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK)) | |
fca41d5a JH |
1847 | request_ocsp = TRUE; |
1848 | else | |
fca41d5a | 1849 | # ifdef EXPERIMENTAL_DANE |
4f59c424 | 1850 | if (!request_ocsp) |
fca41d5a | 1851 | # endif |
5130845b JH |
1852 | request_ocsp = |
1853 | verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
043b1248 | 1854 | } |
f5d78688 | 1855 | #endif |
059ec3d9 | 1856 | |
65867078 JH |
1857 | rc = tls_init(&client_ctx, host, NULL, |
1858 | ob->tls_certificate, ob->tls_privatekey, | |
f2de3a33 | 1859 | #ifndef DISABLE_OCSP |
44662487 | 1860 | (void *)(long)request_ocsp, |
3f7eeb86 | 1861 | #endif |
817d9f57 | 1862 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1863 | if (rc != OK) return rc; |
1864 | ||
817d9f57 | 1865 | tls_out.certificate_verified = FALSE; |
a2ff477a | 1866 | client_verify_callback_called = FALSE; |
059ec3d9 | 1867 | |
65867078 JH |
1868 | if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", |
1869 | &expciphers)) | |
059ec3d9 PH |
1870 | return FAIL; |
1871 | ||
1872 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1873 | are separated by underscores. So that I can use either form in my tests, and | |
1874 | also for general convenience, we turn underscores into hyphens here. */ | |
1875 | ||
1876 | if (expciphers != NULL) | |
1877 | { | |
1878 | uschar *s = expciphers; | |
1879 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1880 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1881 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1882 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1883 | } |
1884 | ||
043b1248 | 1885 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 1886 | if (tlsa_dnsa) |
a63be306 | 1887 | { |
02af313d JH |
1888 | SSL_CTX_set_verify(client_ctx, |
1889 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, | |
1890 | verify_callback_client_dane); | |
e5cccda9 | 1891 | |
043b1248 | 1892 | if (!DANESSL_library_init()) |
b4161d10 | 1893 | return tls_error(US"library init", host, NULL); |
043b1248 | 1894 | if (DANESSL_CTX_init(client_ctx) <= 0) |
b4161d10 | 1895 | return tls_error(US"context init", host, NULL); |
043b1248 JH |
1896 | } |
1897 | else | |
e51c7be2 | 1898 | |
043b1248 JH |
1899 | #endif |
1900 | ||
01a4a5c5 JH |
1901 | if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob, client_static_cbinfo)) |
1902 | != OK) | |
65867078 | 1903 | return rc; |
059ec3d9 | 1904 | |
65867078 JH |
1905 | if ((client_ssl = SSL_new(client_ctx)) == NULL) |
1906 | return tls_error(US"SSL_new", host, NULL); | |
817d9f57 JH |
1907 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1908 | SSL_set_fd(client_ssl, fd); | |
1909 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 1910 | |
65867078 | 1911 | if (ob->tls_sni) |
3f0945ff | 1912 | { |
65867078 | 1913 | if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 1914 | return FAIL; |
ec4b68e5 | 1915 | if (tls_out.sni == NULL) |
2c9a0e86 PP |
1916 | { |
1917 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
1918 | } | |
ec4b68e5 | 1919 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 1920 | tls_out.sni = NULL; |
3f0945ff PP |
1921 | else |
1922 | { | |
35731706 | 1923 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
1924 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
1925 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
1926 | #else |
1927 | DEBUG(D_tls) | |
1928 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
02d9264f | 1929 | tls_out.sni); |
35731706 | 1930 | #endif |
3f0945ff PP |
1931 | } |
1932 | } | |
1933 | ||
594706ea | 1934 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 JH |
1935 | if (tlsa_dnsa) |
1936 | if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa)) != OK) | |
594706ea JH |
1937 | return rc; |
1938 | #endif | |
1939 | ||
f2de3a33 | 1940 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1941 | /* Request certificate status at connection-time. If the server |
1942 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
b50c8b84 | 1943 | # ifdef EXPERIMENTAL_DANE |
594706ea JH |
1944 | if (request_ocsp) |
1945 | { | |
1946 | const uschar * s; | |
41afb5cb JH |
1947 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
1948 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
1949 | ) |
1950 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
1951 | this means we avoid the OCSP request, we wasted the setup | |
1952 | cost in tls_init(). */ | |
5130845b JH |
1953 | require_ocsp = verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; |
1954 | request_ocsp = require_ocsp | |
1955 | || verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
594706ea JH |
1956 | } |
1957 | } | |
b50c8b84 JH |
1958 | # endif |
1959 | ||
44662487 JH |
1960 | if (request_ocsp) |
1961 | { | |
f5d78688 | 1962 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 JH |
1963 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
1964 | tls_out.ocsp = OCSP_NOT_RESP; | |
1965 | } | |
f5d78688 JH |
1966 | #endif |
1967 | ||
774ef2d7 JH |
1968 | #ifdef EXPERIMENTAL_EVENT |
1969 | client_static_cbinfo->event_action = tb->event_action; | |
a7538db1 | 1970 | #endif |
043b1248 | 1971 | |
059ec3d9 PH |
1972 | /* There doesn't seem to be a built-in timeout on connection. */ |
1973 | ||
1974 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1975 | sigalrm_seen = FALSE; | |
65867078 | 1976 | alarm(ob->command_timeout); |
817d9f57 | 1977 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
1978 | alarm(0); |
1979 | ||
043b1248 | 1980 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 1981 | if (tlsa_dnsa) |
fde080a4 | 1982 | DANESSL_cleanup(client_ssl); |
043b1248 JH |
1983 | #endif |
1984 | ||
059ec3d9 | 1985 | if (rc <= 0) |
7199e1ee | 1986 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1987 | |
1988 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1989 | ||
453a6645 | 1990 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
9d1c15ef | 1991 | /*XXX server_cert is never freed... use X509_free() */ |
817d9f57 | 1992 | server_cert = SSL_get_peer_certificate (client_ssl); |
453a6645 PP |
1993 | if (server_cert) |
1994 | { | |
817d9f57 | 1995 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), |
453a6645 | 1996 | CS txt, sizeof(txt)); |
4c01d6ab | 1997 | txt[sizeof(txt)-1] = '\0'; |
9d1c15ef | 1998 | tls_out.peerdn = txt; /*XXX a static buffer... */ |
453a6645 PP |
1999 | } |
2000 | else | |
817d9f57 | 2001 | tls_out.peerdn = NULL; |
059ec3d9 | 2002 | |
817d9f57 JH |
2003 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
2004 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 2005 | |
9d1c15ef JH |
2006 | /* Record the certificate we presented */ |
2007 | { | |
2008 | X509 * crt = SSL_get_certificate(client_ssl); | |
2009 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
2010 | } | |
2011 | ||
817d9f57 | 2012 | tls_out.active = fd; |
059ec3d9 PH |
2013 | return OK; |
2014 | } | |
2015 | ||
2016 | ||
2017 | ||
2018 | ||
2019 | ||
2020 | /************************************************* | |
2021 | * TLS version of getc * | |
2022 | *************************************************/ | |
2023 | ||
2024 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2025 | it refills the buffer via the SSL reading function. | |
2026 | ||
2027 | Arguments: none | |
2028 | Returns: the next character or EOF | |
817d9f57 JH |
2029 | |
2030 | Only used by the server-side TLS. | |
059ec3d9 PH |
2031 | */ |
2032 | ||
2033 | int | |
2034 | tls_getc(void) | |
2035 | { | |
2036 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
2037 | { | |
2038 | int error; | |
2039 | int inbytes; | |
2040 | ||
817d9f57 | 2041 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 2042 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
2043 | |
2044 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
2045 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
2046 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
2047 | alarm(0); |
2048 | ||
2049 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2050 | closed down, not that the socket itself has been closed down. Revert to | |
2051 | non-SSL handling. */ | |
2052 | ||
2053 | if (error == SSL_ERROR_ZERO_RETURN) | |
2054 | { | |
2055 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2056 | ||
2057 | receive_getc = smtp_getc; | |
2058 | receive_ungetc = smtp_ungetc; | |
2059 | receive_feof = smtp_feof; | |
2060 | receive_ferror = smtp_ferror; | |
58eb016e | 2061 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 2062 | |
817d9f57 JH |
2063 | SSL_free(server_ssl); |
2064 | server_ssl = NULL; | |
2065 | tls_in.active = -1; | |
2066 | tls_in.bits = 0; | |
2067 | tls_in.cipher = NULL; | |
2068 | tls_in.peerdn = NULL; | |
2069 | tls_in.sni = NULL; | |
059ec3d9 PH |
2070 | |
2071 | return smtp_getc(); | |
2072 | } | |
2073 | ||
2074 | /* Handle genuine errors */ | |
2075 | ||
ba084640 PP |
2076 | else if (error == SSL_ERROR_SSL) |
2077 | { | |
2078 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 2079 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
2080 | ssl_xfer_error = 1; |
2081 | return EOF; | |
2082 | } | |
2083 | ||
059ec3d9 PH |
2084 | else if (error != SSL_ERROR_NONE) |
2085 | { | |
2086 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2087 | ssl_xfer_error = 1; | |
2088 | return EOF; | |
2089 | } | |
c80c5570 | 2090 | |
80a47a2c TK |
2091 | #ifndef DISABLE_DKIM |
2092 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2093 | #endif | |
059ec3d9 PH |
2094 | ssl_xfer_buffer_hwm = inbytes; |
2095 | ssl_xfer_buffer_lwm = 0; | |
2096 | } | |
2097 | ||
2098 | /* Something in the buffer; return next uschar */ | |
2099 | ||
2100 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
2101 | } | |
2102 | ||
2103 | ||
2104 | ||
2105 | /************************************************* | |
2106 | * Read bytes from TLS channel * | |
2107 | *************************************************/ | |
2108 | ||
2109 | /* | |
2110 | Arguments: | |
2111 | buff buffer of data | |
2112 | len size of buffer | |
2113 | ||
2114 | Returns: the number of bytes read | |
2115 | -1 after a failed read | |
817d9f57 JH |
2116 | |
2117 | Only used by the client-side TLS. | |
059ec3d9 PH |
2118 | */ |
2119 | ||
2120 | int | |
389ca47a | 2121 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2122 | { |
389ca47a | 2123 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
2124 | int inbytes; |
2125 | int error; | |
2126 | ||
389ca47a | 2127 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2128 | buff, (unsigned int)len); |
059ec3d9 | 2129 | |
389ca47a JH |
2130 | inbytes = SSL_read(ssl, CS buff, len); |
2131 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2132 | |
2133 | if (error == SSL_ERROR_ZERO_RETURN) | |
2134 | { | |
2135 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2136 | return -1; | |
2137 | } | |
2138 | else if (error != SSL_ERROR_NONE) | |
2139 | { | |
2140 | return -1; | |
2141 | } | |
2142 | ||
2143 | return inbytes; | |
2144 | } | |
2145 | ||
2146 | ||
2147 | ||
2148 | ||
2149 | ||
2150 | /************************************************* | |
2151 | * Write bytes down TLS channel * | |
2152 | *************************************************/ | |
2153 | ||
2154 | /* | |
2155 | Arguments: | |
817d9f57 | 2156 | is_server channel specifier |
059ec3d9 PH |
2157 | buff buffer of data |
2158 | len number of bytes | |
2159 | ||
2160 | Returns: the number of bytes after a successful write, | |
2161 | -1 after a failed write | |
817d9f57 JH |
2162 | |
2163 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2164 | */ |
2165 | ||
2166 | int | |
817d9f57 | 2167 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
2168 | { |
2169 | int outbytes; | |
2170 | int error; | |
2171 | int left = len; | |
817d9f57 | 2172 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 2173 | |
c80c5570 | 2174 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
2175 | while (left > 0) |
2176 | { | |
c80c5570 | 2177 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
2178 | outbytes = SSL_write(ssl, CS buff, left); |
2179 | error = SSL_get_error(ssl, outbytes); | |
2180 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2181 | switch (error) | |
2182 | { | |
2183 | case SSL_ERROR_SSL: | |
2184 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2185 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
2186 | return -1; | |
2187 | ||
2188 | case SSL_ERROR_NONE: | |
2189 | left -= outbytes; | |
2190 | buff += outbytes; | |
2191 | break; | |
2192 | ||
2193 | case SSL_ERROR_ZERO_RETURN: | |
2194 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
2195 | return -1; | |
2196 | ||
817d9f57 JH |
2197 | case SSL_ERROR_SYSCALL: |
2198 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
2199 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
2200 | strerror(errno)); | |
2201 | ||
059ec3d9 PH |
2202 | default: |
2203 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
2204 | return -1; | |
2205 | } | |
2206 | } | |
2207 | return len; | |
2208 | } | |
2209 | ||
2210 | ||
2211 | ||
2212 | /************************************************* | |
2213 | * Close down a TLS session * | |
2214 | *************************************************/ | |
2215 | ||
2216 | /* This is also called from within a delivery subprocess forked from the | |
2217 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2218 | would tamper with the SSL session in the parent process). | |
2219 | ||
2220 | Arguments: TRUE if SSL_shutdown is to be called | |
2221 | Returns: nothing | |
817d9f57 JH |
2222 | |
2223 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2224 | */ |
2225 | ||
2226 | void | |
817d9f57 | 2227 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2228 | { |
817d9f57 | 2229 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 2230 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
2231 | |
2232 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
2233 | |
2234 | if (shutdown) | |
2235 | { | |
2236 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 2237 | SSL_shutdown(*sslp); |
059ec3d9 PH |
2238 | } |
2239 | ||
817d9f57 JH |
2240 | SSL_free(*sslp); |
2241 | *sslp = NULL; | |
059ec3d9 | 2242 | |
817d9f57 | 2243 | *fdp = -1; |
059ec3d9 PH |
2244 | } |
2245 | ||
36f12725 NM |
2246 | |
2247 | ||
2248 | ||
3375e053 PP |
2249 | /************************************************* |
2250 | * Let tls_require_ciphers be checked at startup * | |
2251 | *************************************************/ | |
2252 | ||
2253 | /* The tls_require_ciphers option, if set, must be something which the | |
2254 | library can parse. | |
2255 | ||
2256 | Returns: NULL on success, or error message | |
2257 | */ | |
2258 | ||
2259 | uschar * | |
2260 | tls_validate_require_cipher(void) | |
2261 | { | |
2262 | SSL_CTX *ctx; | |
2263 | uschar *s, *expciphers, *err; | |
2264 | ||
2265 | /* this duplicates from tls_init(), we need a better "init just global | |
2266 | state, for no specific purpose" singleton function of our own */ | |
2267 | ||
2268 | SSL_load_error_strings(); | |
2269 | OpenSSL_add_ssl_algorithms(); | |
2270 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
2271 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
2272 | list of available digests. */ | |
2273 | EVP_add_digest(EVP_sha256()); | |
2274 | #endif | |
2275 | ||
2276 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2277 | return NULL; | |
2278 | ||
2279 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2280 | return US"failed to expand tls_require_ciphers"; | |
2281 | ||
2282 | if (!(expciphers && *expciphers)) | |
2283 | return NULL; | |
2284 | ||
2285 | /* normalisation ripped from above */ | |
2286 | s = expciphers; | |
2287 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
2288 | ||
2289 | err = NULL; | |
2290 | ||
2291 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
2292 | if (!ctx) | |
2293 | { | |
2294 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2295 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
2296 | } | |
2297 | ||
2298 | DEBUG(D_tls) | |
2299 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2300 | ||
2301 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
2302 | { | |
2303 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2304 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
2305 | } | |
2306 | ||
2307 | SSL_CTX_free(ctx); | |
2308 | ||
2309 | return err; | |
2310 | } | |
2311 | ||
2312 | ||
2313 | ||
2314 | ||
36f12725 NM |
2315 | /************************************************* |
2316 | * Report the library versions. * | |
2317 | *************************************************/ | |
2318 | ||
2319 | /* There have historically been some issues with binary compatibility in | |
2320 | OpenSSL libraries; if Exim (like many other applications) is built against | |
2321 | one version of OpenSSL but the run-time linker picks up another version, | |
2322 | it can result in serious failures, including crashing with a SIGSEGV. So | |
2323 | report the version found by the compiler and the run-time version. | |
2324 | ||
f64a1e23 PP |
2325 | Note: some OS vendors backport security fixes without changing the version |
2326 | number/string, and the version date remains unchanged. The _build_ date | |
2327 | will change, so we can more usefully assist with version diagnosis by also | |
2328 | reporting the build date. | |
2329 | ||
36f12725 NM |
2330 | Arguments: a FILE* to print the results to |
2331 | Returns: nothing | |
2332 | */ | |
2333 | ||
2334 | void | |
2335 | tls_version_report(FILE *f) | |
2336 | { | |
754a0503 | 2337 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
2338 | " Runtime: %s\n" |
2339 | " : %s\n", | |
754a0503 | 2340 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
2341 | SSLeay_version(SSLEAY_VERSION), |
2342 | SSLeay_version(SSLEAY_BUILT_ON)); | |
2343 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
2344 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
2345 | } |
2346 | ||
9e3331ea TK |
2347 | |
2348 | ||
2349 | ||
2350 | /************************************************* | |
17c76198 | 2351 | * Random number generation * |
9e3331ea TK |
2352 | *************************************************/ |
2353 | ||
2354 | /* Pseudo-random number generation. The result is not expected to be | |
2355 | cryptographically strong but not so weak that someone will shoot themselves | |
2356 | in the foot using it as a nonce in input in some email header scheme or | |
2357 | whatever weirdness they'll twist this into. The result should handle fork() | |
2358 | and avoid repeating sequences. OpenSSL handles that for us. | |
2359 | ||
2360 | Arguments: | |
2361 | max range maximum | |
2362 | Returns a random number in range [0, max-1] | |
2363 | */ | |
2364 | ||
2365 | int | |
17c76198 | 2366 | vaguely_random_number(int max) |
9e3331ea TK |
2367 | { |
2368 | unsigned int r; | |
2369 | int i, needed_len; | |
de6135a0 PP |
2370 | static pid_t pidlast = 0; |
2371 | pid_t pidnow; | |
9e3331ea TK |
2372 | uschar *p; |
2373 | uschar smallbuf[sizeof(r)]; | |
2374 | ||
2375 | if (max <= 1) | |
2376 | return 0; | |
2377 | ||
de6135a0 PP |
2378 | pidnow = getpid(); |
2379 | if (pidnow != pidlast) | |
2380 | { | |
2381 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2382 | is unique for each thread", this doesn't apparently apply across processes, | |
2383 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2384 | Fix per PostgreSQL. */ | |
2385 | if (pidlast != 0) | |
2386 | RAND_cleanup(); | |
2387 | pidlast = pidnow; | |
2388 | } | |
2389 | ||
9e3331ea TK |
2390 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
2391 | if (!RAND_status()) | |
2392 | { | |
2393 | randstuff r; | |
2394 | gettimeofday(&r.tv, NULL); | |
2395 | r.p = getpid(); | |
2396 | ||
2397 | RAND_seed((uschar *)(&r), sizeof(r)); | |
2398 | } | |
2399 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2400 | in the internal PRNG then our options are limited. We could sleep and hope | |
2401 | for entropy to come along (prayer technique) but if the system is so depleted | |
2402 | in the first place then something is likely to just keep taking it. Instead, | |
2403 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2404 | get. */ | |
2405 | ||
2406 | needed_len = sizeof(r); | |
2407 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2408 | asked for a number less than 10. */ | |
2409 | for (r = max, i = 0; r; ++i) | |
2410 | r >>= 1; | |
2411 | i = (i + 7) / 8; | |
2412 | if (i < needed_len) | |
2413 | needed_len = i; | |
2414 | ||
2415 | /* We do not care if crypto-strong */ | |
17c76198 PP |
2416 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
2417 | if (i < 0) | |
2418 | { | |
2419 | DEBUG(D_all) | |
2420 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2421 | return vaguely_random_number_fallback(max); | |
2422 | } | |
2423 | ||
9e3331ea TK |
2424 | r = 0; |
2425 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2426 | { | |
2427 | r *= 256; | |
2428 | r += *p; | |
2429 | } | |
2430 | ||
2431 | /* We don't particularly care about weighted results; if someone wants | |
2432 | smooth distribution and cares enough then they should submit a patch then. */ | |
2433 | return r % max; | |
2434 | } | |
2435 | ||
77bb000f PP |
2436 | |
2437 | ||
2438 | ||
2439 | /************************************************* | |
2440 | * OpenSSL option parse * | |
2441 | *************************************************/ | |
2442 | ||
2443 | /* Parse one option for tls_openssl_options_parse below | |
2444 | ||
2445 | Arguments: | |
2446 | name one option name | |
2447 | value place to store a value for it | |
2448 | Returns success or failure in parsing | |
2449 | */ | |
2450 | ||
2451 | struct exim_openssl_option { | |
2452 | uschar *name; | |
2453 | long value; | |
2454 | }; | |
2455 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2456 | options document which version they were introduced in. Policylet: include | |
2457 | all options unless explicitly for DTLS, let the administrator choose which | |
2458 | to apply. | |
2459 | ||
2460 | This list is current as of: | |
e2fbf4a2 PP |
2461 | ==> 1.0.1b <== |
2462 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2463 | */ | |
77bb000f PP |
2464 | static struct exim_openssl_option exim_openssl_options[] = { |
2465 | /* KEEP SORTED ALPHABETICALLY! */ | |
2466 | #ifdef SSL_OP_ALL | |
73a46702 | 2467 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2468 | #endif |
2469 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2470 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2471 | #endif |
2472 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2473 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2474 | #endif |
2475 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2476 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2477 | #endif |
2478 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2479 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2480 | #endif |
2481 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2482 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2483 | #endif |
2484 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2485 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2486 | #endif |
2487 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2488 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2489 | #endif |
2490 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2491 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2492 | #endif |
2493 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2494 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2495 | #endif |
2496 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2497 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2498 | #endif |
c80c5570 PP |
2499 | #ifdef SSL_OP_NO_COMPRESSION |
2500 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2501 | #endif | |
77bb000f | 2502 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2503 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2504 | #endif |
c0c7b2da PP |
2505 | #ifdef SSL_OP_NO_SSLv2 |
2506 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2507 | #endif | |
2508 | #ifdef SSL_OP_NO_SSLv3 | |
2509 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2510 | #endif | |
2511 | #ifdef SSL_OP_NO_TICKET | |
2512 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2513 | #endif | |
2514 | #ifdef SSL_OP_NO_TLSv1 | |
2515 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2516 | #endif | |
c80c5570 PP |
2517 | #ifdef SSL_OP_NO_TLSv1_1 |
2518 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2519 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2520 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2521 | #else | |
2522 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2523 | #endif | |
2524 | #endif | |
2525 | #ifdef SSL_OP_NO_TLSv1_2 | |
2526 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2527 | #endif | |
e2fbf4a2 PP |
2528 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG |
2529 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2530 | #endif | |
77bb000f | 2531 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2532 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2533 | #endif |
2534 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2535 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2536 | #endif |
2537 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2538 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2539 | #endif |
2540 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2541 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2542 | #endif |
2543 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2544 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2545 | #endif |
2546 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2547 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2548 | #endif |
2549 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2550 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2551 | #endif |
2552 | }; | |
2553 | static int exim_openssl_options_size = | |
2554 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2555 | ||
c80c5570 | 2556 | |
77bb000f PP |
2557 | static BOOL |
2558 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2559 | { | |
2560 | int first = 0; | |
2561 | int last = exim_openssl_options_size; | |
2562 | while (last > first) | |
2563 | { | |
2564 | int middle = (first + last)/2; | |
2565 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2566 | if (c == 0) | |
2567 | { | |
2568 | *value = exim_openssl_options[middle].value; | |
2569 | return TRUE; | |
2570 | } | |
2571 | else if (c > 0) | |
2572 | first = middle + 1; | |
2573 | else | |
2574 | last = middle; | |
2575 | } | |
2576 | return FALSE; | |
2577 | } | |
2578 | ||
2579 | ||
2580 | ||
2581 | ||
2582 | /************************************************* | |
2583 | * OpenSSL option parsing logic * | |
2584 | *************************************************/ | |
2585 | ||
2586 | /* OpenSSL has a number of compatibility options which an administrator might | |
2587 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2588 | we look like log_selector. | |
2589 | ||
2590 | Arguments: | |
2591 | option_spec the administrator-supplied string of options | |
2592 | results ptr to long storage for the options bitmap | |
2593 | Returns success or failure | |
2594 | */ | |
2595 | ||
2596 | BOOL | |
2597 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2598 | { | |
2599 | long result, item; | |
2600 | uschar *s, *end; | |
2601 | uschar keep_c; | |
2602 | BOOL adding, item_parsed; | |
2603 | ||
0e944a0d | 2604 | result = 0L; |
b1770b6e | 2605 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 2606 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
2607 | #ifdef SSL_OP_NO_SSLv2 |
2608 | result |= SSL_OP_NO_SSLv2; | |
2609 | #endif | |
77bb000f PP |
2610 | |
2611 | if (option_spec == NULL) | |
2612 | { | |
2613 | *results = result; | |
2614 | return TRUE; | |
2615 | } | |
2616 | ||
2617 | for (s=option_spec; *s != '\0'; /**/) | |
2618 | { | |
2619 | while (isspace(*s)) ++s; | |
2620 | if (*s == '\0') | |
2621 | break; | |
2622 | if (*s != '+' && *s != '-') | |
2623 | { | |
2624 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 2625 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
2626 | return FALSE; |
2627 | } | |
2628 | adding = *s++ == '+'; | |
2629 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2630 | keep_c = *end; | |
2631 | *end = '\0'; | |
2632 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2633 | if (!item_parsed) | |
2634 | { | |
0e944a0d | 2635 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
2636 | return FALSE; |
2637 | } | |
2638 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2639 | adding ? "adding" : "removing", result, item, s); | |
2640 | if (adding) | |
2641 | result |= item; | |
2642 | else | |
2643 | result &= ~item; | |
2644 | *end = keep_c; | |
2645 | s = end; | |
2646 | } | |
2647 | ||
2648 | *results = result; | |
2649 | return TRUE; | |
2650 | } | |
2651 | ||
9d1c15ef JH |
2652 | /* vi: aw ai sw=2 |
2653 | */ | |
059ec3d9 | 2654 | /* End of tls-openssl.c */ |