Commit | Line | Data |
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420a0d19 CE |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
5 | /* Copyright (c) University of Cambridge 1995 - 2014 */ | |
6 | /* See the file NOTICE for conditions of use and distribution. */ | |
7 | ||
8 | /* Portions Copyright (c) The OpenSSL Project 1999 */ | |
9 | ||
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> | |
25 | #ifndef DISABLE_OCSP | |
26 | # include <openssl/ocsp.h> | |
27 | #endif | |
28 | ||
29 | #ifndef DISABLE_OCSP | |
30 | # define EXIM_OCSP_SKEW_SECONDS (300L) | |
31 | # define EXIM_OCSP_MAX_AGE (-1L) | |
32 | #endif | |
33 | ||
34 | #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) | |
35 | # define EXIM_HAVE_OPENSSL_TLSEXT | |
36 | #endif | |
37 | ||
38 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) | |
39 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
40 | # define DISABLE_OCSP | |
41 | #endif | |
42 | ||
43 | /* Structure for collecting random data for seeding. */ | |
44 | ||
45 | typedef struct randstuff { | |
46 | struct timeval tv; | |
47 | pid_t p; | |
48 | } randstuff; | |
49 | ||
50 | /* Local static variables */ | |
51 | ||
52 | static BOOL client_verify_callback_called = FALSE; | |
53 | static BOOL server_verify_callback_called = FALSE; | |
54 | static const uschar *sid_ctx = US"exim"; | |
55 | ||
56 | /* We have three different contexts to care about. | |
57 | ||
58 | Simple case: client, `client_ctx` | |
59 | As a client, we can be doing a callout or cut-through delivery while receiving | |
60 | a message. So we have a client context, which should have options initialised | |
61 | from the SMTP Transport. | |
62 | ||
63 | Server: | |
64 | There are two cases: with and without ServerNameIndication from the client. | |
65 | Given TLS SNI, we can be using different keys, certs and various other | |
66 | configuration settings, because they're re-expanded with $tls_sni set. This | |
67 | allows vhosting with TLS. This SNI is sent in the handshake. | |
68 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
69 | So as a server, we start out using `server_ctx`. | |
70 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
71 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
72 | configuration. | |
73 | */ | |
74 | ||
75 | static SSL_CTX *client_ctx = NULL; | |
76 | static SSL_CTX *server_ctx = NULL; | |
77 | static SSL *client_ssl = NULL; | |
78 | static SSL *server_ssl = NULL; | |
79 | ||
80 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT | |
81 | static SSL_CTX *server_sni = NULL; | |
82 | #endif | |
83 | ||
84 | static char ssl_errstring[256]; | |
85 | ||
86 | static int ssl_session_timeout = 200; | |
87 | static BOOL client_verify_optional = FALSE; | |
88 | static BOOL server_verify_optional = FALSE; | |
89 | ||
90 | static BOOL reexpand_tls_files_for_sni = FALSE; | |
91 | ||
92 | ||
93 | typedef struct tls_ext_ctx_cb { | |
94 | uschar *certificate; | |
95 | uschar *privatekey; | |
96 | #ifndef DISABLE_OCSP | |
97 | BOOL is_server; | |
98 | union { | |
99 | struct { | |
100 | uschar *file; | |
101 | uschar *file_expanded; | |
102 | OCSP_RESPONSE *response; | |
103 | } server; | |
104 | struct { | |
105 | X509_STORE *verify_store; /* non-null if status requested */ | |
106 | BOOL verify_required; | |
107 | } client; | |
108 | } u_ocsp; | |
109 | #endif | |
110 | uschar *dhparam; | |
111 | /* these are cached from first expand */ | |
112 | uschar *server_cipher_list; | |
113 | /* only passed down to tls_error: */ | |
114 | host_item *host; | |
115 | ||
116 | #ifdef EXPERIMENTAL_CERTNAMES | |
117 | uschar * verify_cert_hostnames; | |
118 | #endif | |
119 | } tls_ext_ctx_cb; | |
120 | ||
121 | /* should figure out a cleanup of API to handle state preserved per | |
122 | implementation, for various reasons, which can be void * in the APIs. | |
123 | For now, we hack around it. */ | |
124 | tls_ext_ctx_cb *client_static_cbinfo = NULL; | |
125 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
126 | ||
127 | static int | |
128 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, | |
129 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ); | |
130 | ||
131 | /* Callbacks */ | |
132 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT | |
133 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); | |
134 | #endif | |
135 | #ifndef DISABLE_OCSP | |
136 | static int tls_server_stapling_cb(SSL *s, void *arg); | |
137 | #endif | |
138 | ||
139 | ||
140 | /************************************************* | |
141 | * Handle TLS error * | |
142 | *************************************************/ | |
143 | ||
144 | /* Called from lots of places when errors occur before actually starting to do | |
145 | the TLS handshake, that is, while the session is still in clear. Always returns | |
146 | DEFER for a server and FAIL for a client so that most calls can use "return | |
147 | tls_error(...)" to do this processing and then give an appropriate return. A | |
148 | single function is used for both server and client, because it is called from | |
149 | some shared functions. | |
150 | ||
151 | Argument: | |
152 | prefix text to include in the logged error | |
153 | host NULL if setting up a server; | |
154 | the connected host if setting up a client | |
155 | msg error message or NULL if we should ask OpenSSL | |
156 | ||
157 | Returns: OK/DEFER/FAIL | |
158 | */ | |
159 | ||
160 | static int | |
161 | tls_error(uschar *prefix, host_item *host, uschar *msg) | |
162 | { | |
163 | if (msg == NULL) | |
164 | { | |
165 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
166 | msg = (uschar *)ssl_errstring; | |
167 | } | |
168 | ||
169 | if (host == NULL) | |
170 | { | |
171 | uschar *conn_info = smtp_get_connection_info(); | |
172 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) | |
173 | conn_info += 5; | |
174 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
175 | conn_info, prefix, msg); | |
176 | return DEFER; | |
177 | } | |
178 | else | |
179 | { | |
180 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
181 | host->name, host->address, prefix, msg); | |
182 | return FAIL; | |
183 | } | |
184 | } | |
185 | ||
186 | ||
187 | ||
188 | /************************************************* | |
189 | * Callback to generate RSA key * | |
190 | *************************************************/ | |
191 | ||
192 | /* | |
193 | Arguments: | |
194 | s SSL connection | |
195 | export not used | |
196 | keylength keylength | |
197 | ||
198 | Returns: pointer to generated key | |
199 | */ | |
200 | ||
201 | static RSA * | |
202 | rsa_callback(SSL *s, int export, int keylength) | |
203 | { | |
204 | RSA *rsa_key; | |
205 | export = export; /* Shut picky compilers up */ | |
206 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
207 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
208 | if (rsa_key == NULL) | |
209 | { | |
210 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
211 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
212 | ssl_errstring); | |
213 | return NULL; | |
214 | } | |
215 | return rsa_key; | |
216 | } | |
217 | ||
218 | ||
219 | ||
220 | /* Extreme debug | |
221 | #ifndef DISABLE_OCSP | |
222 | void | |
223 | x509_store_dump_cert_s_names(X509_STORE * store) | |
224 | { | |
225 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
226 | int i; | |
227 | static uschar name[256]; | |
228 | ||
229 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
230 | { | |
231 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
232 | if(tmp_obj->type == X509_LU_X509) | |
233 | { | |
234 | X509 * current_cert= tmp_obj->data.x509; | |
235 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
236 | debug_printf(" %s\n", name); | |
237 | } | |
238 | } | |
239 | } | |
240 | #endif | |
241 | */ | |
242 | ||
243 | ||
244 | /************************************************* | |
245 | * Callback for verification * | |
246 | *************************************************/ | |
247 | ||
248 | /* The SSL library does certificate verification if set up to do so. This | |
249 | callback has the current yes/no state is in "state". If verification succeeded, | |
250 | we set up the tls_peerdn string. If verification failed, what happens depends | |
251 | on whether the client is required to present a verifiable certificate or not. | |
252 | ||
253 | If verification is optional, we change the state to yes, but still log the | |
254 | verification error. For some reason (it really would help to have proper | |
255 | documentation of OpenSSL), this callback function then gets called again, this | |
256 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
257 | value, but we must take care not to set the private verified flag on the second | |
258 | time through. | |
259 | ||
260 | Note: this function is not called if the client fails to present a certificate | |
261 | when asked. We get here only if a certificate has been received. Handling of | |
262 | optional verification for this case is done when requesting SSL to verify, by | |
263 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
264 | ||
265 | Arguments: | |
266 | state current yes/no state as 1/0 | |
267 | x509ctx certificate information. | |
268 | client TRUE for client startup, FALSE for server startup | |
269 | ||
270 | Returns: 1 if verified, 0 if not | |
271 | */ | |
272 | ||
273 | static int | |
274 | verify_callback(int state, X509_STORE_CTX *x509ctx, | |
275 | tls_support *tlsp, BOOL *calledp, BOOL *optionalp) | |
276 | { | |
277 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
278 | static uschar txt[256]; | |
279 | ||
280 | X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); | |
281 | ||
282 | if (state == 0) | |
283 | { | |
284 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
285 | X509_STORE_CTX_get_error_depth(x509ctx), | |
286 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), | |
287 | txt); | |
288 | tlsp->certificate_verified = FALSE; | |
289 | *calledp = TRUE; | |
290 | if (!*optionalp) | |
291 | { | |
292 | tlsp->peercert = X509_dup(cert); | |
293 | return 0; /* reject */ | |
294 | } | |
295 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " | |
296 | "tls_try_verify_hosts)\n"); | |
297 | } | |
298 | ||
299 | else if (X509_STORE_CTX_get_error_depth(x509ctx) != 0) | |
300 | { | |
301 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", | |
302 | X509_STORE_CTX_get_error_depth(x509ctx), txt); | |
303 | #ifndef DISABLE_OCSP | |
304 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) | |
305 | { /* client, wanting stapling */ | |
306 | /* Add the server cert's signing chain as the one | |
307 | for the verification of the OCSP stapled information. */ | |
308 | ||
309 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
310 | cert)) | |
311 | ERR_clear_error(); | |
312 | } | |
313 | #endif | |
314 | } | |
315 | else | |
316 | { | |
317 | #ifdef EXPERIMENTAL_CERTNAMES | |
318 | uschar * verify_cert_hostnames; | |
319 | #endif | |
320 | ||
321 | tlsp->peerdn = txt; | |
322 | tlsp->peercert = X509_dup(cert); | |
323 | ||
324 | #ifdef EXPERIMENTAL_CERTNAMES | |
325 | if ( tlsp == &tls_out | |
326 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
327 | /* client, wanting hostname check */ | |
328 | ||
329 | # if OPENSSL_VERSION_NUMBER >= 0x010100000L || OPENSSL_VERSION_NUMBER >= 0x010002000L | |
330 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS | |
331 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
332 | # endif | |
333 | { | |
334 | int sep = 0; | |
335 | uschar * list = verify_cert_hostnames; | |
336 | uschar * name; | |
337 | int rc; | |
338 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
339 | if ((rc = X509_check_host(cert, name, 0, | |
340 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS))) | |
341 | { | |
342 | if (rc < 0) | |
343 | { | |
344 | log_write(0, LOG_MAIN, "SSL verify error: internal error\n"); | |
345 | name = NULL; | |
346 | } | |
347 | break; | |
348 | } | |
349 | if (!name) | |
350 | { | |
351 | log_write(0, LOG_MAIN, | |
352 | "SSL verify error: certificate name mismatch: \"%s\"\n", txt); | |
353 | return 0; /* reject */ | |
354 | } | |
355 | } | |
356 | # else | |
357 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) | |
358 | { | |
359 | log_write(0, LOG_MAIN, | |
360 | "SSL verify error: certificate name mismatch: \"%s\"\n", txt); | |
361 | return 0; /* reject */ | |
362 | } | |
363 | # endif | |
364 | #endif | |
365 | ||
366 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", | |
367 | *calledp ? "" : " authenticated", txt); | |
368 | if (!*calledp) tlsp->certificate_verified = TRUE; | |
369 | *calledp = TRUE; | |
370 | } | |
371 | ||
372 | return 1; /* accept */ | |
373 | } | |
374 | ||
375 | static int | |
376 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
377 | { | |
378 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); | |
379 | } | |
380 | ||
381 | static int | |
382 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
383 | { | |
384 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); | |
385 | } | |
386 | ||
387 | ||
388 | ||
389 | /************************************************* | |
390 | * Information callback * | |
391 | *************************************************/ | |
392 | ||
393 | /* The SSL library functions call this from time to time to indicate what they | |
394 | are doing. We copy the string to the debugging output when TLS debugging has | |
395 | been requested. | |
396 | ||
397 | Arguments: | |
398 | s the SSL connection | |
399 | where | |
400 | ret | |
401 | ||
402 | Returns: nothing | |
403 | */ | |
404 | ||
405 | static void | |
406 | info_callback(SSL *s, int where, int ret) | |
407 | { | |
408 | where = where; | |
409 | ret = ret; | |
410 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
411 | } | |
412 | ||
413 | ||
414 | ||
415 | /************************************************* | |
416 | * Initialize for DH * | |
417 | *************************************************/ | |
418 | ||
419 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
420 | ||
421 | Arguments: | |
422 | dhparam DH parameter file or fixed parameter identity string | |
423 | host connected host, if client; NULL if server | |
424 | ||
425 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
426 | */ | |
427 | ||
428 | static BOOL | |
429 | init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host) | |
430 | { | |
431 | BIO *bio; | |
432 | DH *dh; | |
433 | uschar *dhexpanded; | |
434 | const char *pem; | |
435 | ||
436 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
437 | return FALSE; | |
438 | ||
439 | if (!dhexpanded || !*dhexpanded) | |
440 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); | |
441 | else if (dhexpanded[0] == '/') | |
442 | { | |
443 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) | |
444 | { | |
445 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), | |
446 | host, US strerror(errno)); | |
447 | return FALSE; | |
448 | } | |
449 | } | |
450 | else | |
451 | { | |
452 | if (Ustrcmp(dhexpanded, "none") == 0) | |
453 | { | |
454 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
455 | return TRUE; | |
456 | } | |
457 | ||
458 | if (!(pem = std_dh_prime_named(dhexpanded))) | |
459 | { | |
460 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
461 | host, US strerror(errno)); | |
462 | return FALSE; | |
463 | } | |
464 | bio = BIO_new_mem_buf(CS pem, -1); | |
465 | } | |
466 | ||
467 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) | |
468 | { | |
469 | BIO_free(bio); | |
470 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), | |
471 | host, NULL); | |
472 | return FALSE; | |
473 | } | |
474 | ||
475 | /* Even if it is larger, we silently return success rather than cause things | |
476 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
477 | * debatable choice. */ | |
478 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
479 | { | |
480 | DEBUG(D_tls) | |
481 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
482 | 8*DH_size(dh), tls_dh_max_bits); | |
483 | } | |
484 | else | |
485 | { | |
486 | SSL_CTX_set_tmp_dh(sctx, dh); | |
487 | DEBUG(D_tls) | |
488 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
489 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
490 | } | |
491 | ||
492 | DH_free(dh); | |
493 | BIO_free(bio); | |
494 | ||
495 | return TRUE; | |
496 | } | |
497 | ||
498 | ||
499 | ||
500 | ||
501 | #ifndef DISABLE_OCSP | |
502 | /************************************************* | |
503 | * Load OCSP information into state * | |
504 | *************************************************/ | |
505 | ||
506 | /* Called to load the server OCSP response from the given file into memory, once | |
507 | caller has determined this is needed. Checks validity. Debugs a message | |
508 | if invalid. | |
509 | ||
510 | ASSUMES: single response, for single cert. | |
511 | ||
512 | Arguments: | |
513 | sctx the SSL_CTX* to update | |
514 | cbinfo various parts of session state | |
515 | expanded the filename putatively holding an OCSP response | |
516 | ||
517 | */ | |
518 | ||
519 | static void | |
520 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) | |
521 | { | |
522 | BIO *bio; | |
523 | OCSP_RESPONSE *resp; | |
524 | OCSP_BASICRESP *basic_response; | |
525 | OCSP_SINGLERESP *single_response; | |
526 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
527 | X509_STORE *store; | |
528 | unsigned long verify_flags; | |
529 | int status, reason, i; | |
530 | ||
531 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); | |
532 | if (cbinfo->u_ocsp.server.response) | |
533 | { | |
534 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); | |
535 | cbinfo->u_ocsp.server.response = NULL; | |
536 | } | |
537 | ||
538 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); | |
539 | if (!bio) | |
540 | { | |
541 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
542 | cbinfo->u_ocsp.server.file_expanded); | |
543 | return; | |
544 | } | |
545 | ||
546 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
547 | BIO_free(bio); | |
548 | if (!resp) | |
549 | { | |
550 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
551 | return; | |
552 | } | |
553 | ||
554 | status = OCSP_response_status(resp); | |
555 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
556 | { | |
557 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
558 | OCSP_response_status_str(status), status); | |
559 | goto bad; | |
560 | } | |
561 | ||
562 | basic_response = OCSP_response_get1_basic(resp); | |
563 | if (!basic_response) | |
564 | { | |
565 | DEBUG(D_tls) | |
566 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
567 | goto bad; | |
568 | } | |
569 | ||
570 | store = SSL_CTX_get_cert_store(sctx); | |
571 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
572 | ||
573 | /* May need to expose ability to adjust those flags? | |
574 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
575 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
576 | ||
577 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
578 | if (i <= 0) | |
579 | { | |
580 | DEBUG(D_tls) { | |
581 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
582 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
583 | } | |
584 | goto bad; | |
585 | } | |
586 | ||
587 | /* Here's the simplifying assumption: there's only one response, for the | |
588 | one certificate we use, and nothing for anything else in a chain. If this | |
589 | proves false, we need to extract a cert id from our issued cert | |
590 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
591 | right cert in the stack and then calls OCSP_single_get0_status()). | |
592 | ||
593 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
594 | single_response = OCSP_resp_get0(basic_response, 0); | |
595 | if (!single_response) | |
596 | { | |
597 | DEBUG(D_tls) | |
598 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
599 | goto bad; | |
600 | } | |
601 | ||
602 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
603 | if (status != V_OCSP_CERTSTATUS_GOOD) | |
604 | { | |
605 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", | |
606 | OCSP_cert_status_str(status), status, | |
607 | OCSP_crl_reason_str(reason), reason); | |
608 | goto bad; | |
609 | } | |
610 | ||
611 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
612 | { | |
613 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
614 | goto bad; | |
615 | } | |
616 | ||
617 | supply_response: | |
618 | cbinfo->u_ocsp.server.response = resp; | |
619 | return; | |
620 | ||
621 | bad: | |
622 | if (running_in_test_harness) | |
623 | { | |
624 | extern char ** environ; | |
625 | uschar ** p; | |
188b6fee | 626 | if (environ) for (p = USS environ; *p != NULL; p++) |
420a0d19 CE |
627 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) |
628 | { | |
629 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
630 | goto supply_response; | |
631 | } | |
632 | } | |
633 | return; | |
634 | } | |
635 | #endif /*!DISABLE_OCSP*/ | |
636 | ||
637 | ||
638 | ||
639 | ||
640 | /************************************************* | |
641 | * Expand key and cert file specs * | |
642 | *************************************************/ | |
643 | ||
644 | /* Called once during tls_init and possibly again during TLS setup, for a | |
645 | new context, if Server Name Indication was used and tls_sni was seen in | |
646 | the certificate string. | |
647 | ||
648 | Arguments: | |
649 | sctx the SSL_CTX* to update | |
650 | cbinfo various parts of session state | |
651 | ||
652 | Returns: OK/DEFER/FAIL | |
653 | */ | |
654 | ||
655 | static int | |
656 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) | |
657 | { | |
658 | uschar *expanded; | |
659 | ||
660 | if (cbinfo->certificate == NULL) | |
661 | return OK; | |
662 | ||
663 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || | |
664 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
665 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
666 | ) | |
667 | reexpand_tls_files_for_sni = TRUE; | |
668 | ||
669 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
670 | return DEFER; | |
671 | ||
672 | if (expanded != NULL) | |
673 | { | |
674 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
675 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
676 | return tls_error(string_sprintf( | |
677 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
678 | cbinfo->host, NULL); | |
679 | } | |
680 | ||
681 | if (cbinfo->privatekey != NULL && | |
682 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
683 | return DEFER; | |
684 | ||
685 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
686 | of the expansion is an empty string, ignore it also, and assume the private | |
687 | key is in the same file as the certificate. */ | |
688 | ||
689 | if (expanded != NULL && *expanded != 0) | |
690 | { | |
691 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
692 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
693 | return tls_error(string_sprintf( | |
694 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
695 | } | |
696 | ||
697 | #ifndef DISABLE_OCSP | |
698 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) | |
699 | { | |
700 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) | |
701 | return DEFER; | |
702 | ||
703 | if (expanded != NULL && *expanded != 0) | |
704 | { | |
705 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
706 | if (cbinfo->u_ocsp.server.file_expanded && | |
707 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
708 | { | |
709 | DEBUG(D_tls) | |
710 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
711 | } else { | |
712 | ocsp_load_response(sctx, cbinfo, expanded); | |
713 | } | |
714 | } | |
715 | } | |
716 | #endif | |
717 | ||
718 | return OK; | |
719 | } | |
720 | ||
721 | ||
722 | ||
723 | ||
724 | /************************************************* | |
725 | * Callback to handle SNI * | |
726 | *************************************************/ | |
727 | ||
728 | /* Called when acting as server during the TLS session setup if a Server Name | |
729 | Indication extension was sent by the client. | |
730 | ||
731 | API documentation is OpenSSL s_server.c implementation. | |
732 | ||
733 | Arguments: | |
734 | s SSL* of the current session | |
735 | ad unknown (part of OpenSSL API) (unused) | |
736 | arg Callback of "our" registered data | |
737 | ||
738 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
739 | */ | |
740 | ||
741 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT | |
742 | static int | |
743 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
744 | { | |
745 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
746 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
747 | int rc; | |
748 | int old_pool = store_pool; | |
749 | ||
750 | if (!servername) | |
751 | return SSL_TLSEXT_ERR_OK; | |
752 | ||
753 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, | |
754 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); | |
755 | ||
756 | /* Make the extension value available for expansion */ | |
757 | store_pool = POOL_PERM; | |
758 | tls_in.sni = string_copy(US servername); | |
759 | store_pool = old_pool; | |
760 | ||
761 | if (!reexpand_tls_files_for_sni) | |
762 | return SSL_TLSEXT_ERR_OK; | |
763 | ||
764 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
765 | not confident that memcpy wouldn't break some internal reference counting. | |
766 | Especially since there's a references struct member, which would be off. */ | |
767 | ||
768 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) | |
769 | { | |
770 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
771 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
772 | return SSL_TLSEXT_ERR_NOACK; | |
773 | } | |
774 | ||
775 | /* Not sure how many of these are actually needed, since SSL object | |
776 | already exists. Might even need this selfsame callback, for reneg? */ | |
777 | ||
778 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); | |
779 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
780 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
781 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
782 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
783 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
784 | if (cbinfo->server_cipher_list) | |
785 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); | |
786 | #ifndef DISABLE_OCSP | |
787 | if (cbinfo->u_ocsp.server.file) | |
788 | { | |
789 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); | |
790 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); | |
791 | } | |
792 | #endif | |
793 | ||
794 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server); | |
795 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; | |
796 | ||
797 | /* do this after setup_certs, because this can require the certs for verifying | |
798 | OCSP information. */ | |
799 | rc = tls_expand_session_files(server_sni, cbinfo); | |
800 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; | |
801 | ||
802 | if (!init_dh(server_sni, cbinfo->dhparam, NULL)) | |
803 | return SSL_TLSEXT_ERR_NOACK; | |
804 | ||
805 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); | |
806 | SSL_set_SSL_CTX(s, server_sni); | |
807 | ||
808 | return SSL_TLSEXT_ERR_OK; | |
809 | } | |
810 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ | |
811 | ||
812 | ||
813 | ||
814 | ||
815 | #ifndef DISABLE_OCSP | |
816 | ||
817 | /************************************************* | |
818 | * Callback to handle OCSP Stapling * | |
819 | *************************************************/ | |
820 | ||
821 | /* Called when acting as server during the TLS session setup if the client | |
822 | requests OCSP information with a Certificate Status Request. | |
823 | ||
824 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
825 | project. | |
826 | ||
827 | */ | |
828 | ||
829 | static int | |
830 | tls_server_stapling_cb(SSL *s, void *arg) | |
831 | { | |
832 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
833 | uschar *response_der; | |
834 | int response_der_len; | |
835 | ||
836 | DEBUG(D_tls) | |
837 | debug_printf("Received TLS status request (OCSP stapling); %s response.", | |
838 | cbinfo->u_ocsp.server.response ? "have" : "lack"); | |
839 | ||
840 | tls_in.ocsp = OCSP_NOT_RESP; | |
841 | if (!cbinfo->u_ocsp.server.response) | |
842 | return SSL_TLSEXT_ERR_NOACK; | |
843 | ||
844 | response_der = NULL; | |
845 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, | |
846 | &response_der); | |
847 | if (response_der_len <= 0) | |
848 | return SSL_TLSEXT_ERR_NOACK; | |
849 | ||
850 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); | |
851 | tls_in.ocsp = OCSP_VFIED; | |
852 | return SSL_TLSEXT_ERR_OK; | |
853 | } | |
854 | ||
855 | ||
856 | static void | |
857 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
858 | { | |
859 | BIO_printf(bp, "\t%s: ", str); | |
860 | ASN1_GENERALIZEDTIME_print(bp, time); | |
861 | BIO_puts(bp, "\n"); | |
862 | } | |
863 | ||
864 | static int | |
865 | tls_client_stapling_cb(SSL *s, void *arg) | |
866 | { | |
867 | tls_ext_ctx_cb * cbinfo = arg; | |
868 | const unsigned char * p; | |
869 | int len; | |
870 | OCSP_RESPONSE * rsp; | |
871 | OCSP_BASICRESP * bs; | |
872 | int i; | |
873 | ||
874 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
875 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
876 | if(!p) | |
877 | { | |
878 | /* Expect this when we requested ocsp but got none */ | |
879 | if ( cbinfo->u_ocsp.client.verify_required | |
880 | && log_extra_selector & LX_tls_cipher) | |
881 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); | |
882 | else | |
883 | DEBUG(D_tls) debug_printf(" null\n"); | |
884 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
885 | } | |
886 | ||
887 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) | |
888 | { | |
889 | tls_out.ocsp = OCSP_FAILED; | |
890 | if (log_extra_selector & LX_tls_cipher) | |
891 | log_write(0, LOG_MAIN, "Received TLS status response, parse error"); | |
892 | else | |
893 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
894 | return 0; | |
895 | } | |
896 | ||
897 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
898 | { | |
899 | tls_out.ocsp = OCSP_FAILED; | |
900 | if (log_extra_selector & LX_tls_cipher) | |
901 | log_write(0, LOG_MAIN, "Received TLS status response, error parsing response"); | |
902 | else | |
903 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
904 | OCSP_RESPONSE_free(rsp); | |
905 | return 0; | |
906 | } | |
907 | ||
908 | /* We'd check the nonce here if we'd put one in the request. */ | |
909 | /* However that would defeat cacheability on the server so we don't. */ | |
910 | ||
911 | /* This section of code reworked from OpenSSL apps source; | |
912 | The OpenSSL Project retains copyright: | |
913 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
914 | */ | |
915 | { | |
916 | BIO * bp = NULL; | |
917 | int status, reason; | |
918 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
919 | ||
920 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
921 | ||
922 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
923 | ||
924 | /* Use the chain that verified the server cert to verify the stapled info */ | |
925 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
926 | ||
927 | if ((i = OCSP_basic_verify(bs, NULL, | |
928 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
929 | { | |
930 | tls_out.ocsp = OCSP_FAILED; | |
931 | BIO_printf(bp, "OCSP response verify failure\n"); | |
932 | ERR_print_errors(bp); | |
933 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
934 | goto out; | |
935 | } | |
936 | ||
937 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
938 | ||
939 | { | |
940 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
941 | OCSP_SINGLERESP * single; | |
942 | ||
943 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
944 | { | |
945 | tls_out.ocsp = OCSP_FAILED; | |
946 | log_write(0, LOG_MAIN, "OCSP stapling " | |
947 | "with multiple responses not handled"); | |
948 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
949 | goto out; | |
950 | } | |
951 | single = OCSP_resp_get0(bs, 0); | |
952 | status = OCSP_single_get0_status(single, &reason, &rev, | |
953 | &thisupd, &nextupd); | |
954 | } | |
955 | ||
956 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); | |
957 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
958 | if (!OCSP_check_validity(thisupd, nextupd, | |
959 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
960 | { | |
961 | tls_out.ocsp = OCSP_FAILED; | |
962 | DEBUG(D_tls) ERR_print_errors(bp); | |
963 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
964 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
965 | } | |
966 | else | |
967 | { | |
968 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", | |
969 | OCSP_cert_status_str(status)); | |
970 | switch(status) | |
971 | { | |
972 | case V_OCSP_CERTSTATUS_GOOD: | |
973 | tls_out.ocsp = OCSP_VFIED; | |
974 | i = 1; | |
975 | break; | |
976 | case V_OCSP_CERTSTATUS_REVOKED: | |
977 | tls_out.ocsp = OCSP_FAILED; | |
978 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", | |
979 | reason != -1 ? "; reason: " : "", | |
980 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
981 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
982 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
983 | break; | |
984 | default: | |
985 | tls_out.ocsp = OCSP_FAILED; | |
986 | log_write(0, LOG_MAIN, | |
987 | "Server certificate status unknown, in OCSP stapling"); | |
988 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
989 | break; | |
990 | } | |
991 | } | |
992 | out: | |
993 | BIO_free(bp); | |
994 | } | |
995 | ||
996 | OCSP_RESPONSE_free(rsp); | |
997 | return i; | |
998 | } | |
999 | #endif /*!DISABLE_OCSP*/ | |
1000 | ||
1001 | ||
1002 | ||
1003 | /************************************************* | |
1004 | * Initialize for TLS * | |
1005 | *************************************************/ | |
1006 | ||
1007 | /* Called from both server and client code, to do preliminary initialization | |
1008 | of the library. We allocate and return a context structure. | |
1009 | ||
1010 | Arguments: | |
1011 | host connected host, if client; NULL if server | |
1012 | dhparam DH parameter file | |
1013 | certificate certificate file | |
1014 | privatekey private key | |
1015 | ocsp_file file of stapling info (server); flag for require ocsp (client) | |
1016 | addr address if client; NULL if server (for some randomness) | |
1017 | cbp place to put allocated context | |
1018 | ||
1019 | Returns: OK/DEFER/FAIL | |
1020 | */ | |
1021 | ||
1022 | static int | |
1023 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, | |
1024 | uschar *privatekey, | |
1025 | #ifndef DISABLE_OCSP | |
1026 | uschar *ocsp_file, | |
1027 | #endif | |
1028 | address_item *addr, tls_ext_ctx_cb ** cbp) | |
1029 | { | |
1030 | long init_options; | |
1031 | int rc; | |
1032 | BOOL okay; | |
1033 | tls_ext_ctx_cb *cbinfo; | |
1034 | ||
1035 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1036 | cbinfo->certificate = certificate; | |
1037 | cbinfo->privatekey = privatekey; | |
1038 | #ifndef DISABLE_OCSP | |
1039 | if ((cbinfo->is_server = host==NULL)) | |
1040 | { | |
1041 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1042 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1043 | cbinfo->u_ocsp.server.response = NULL; | |
1044 | } | |
1045 | else | |
1046 | cbinfo->u_ocsp.client.verify_store = NULL; | |
1047 | #endif | |
1048 | cbinfo->dhparam = dhparam; | |
1049 | cbinfo->server_cipher_list = NULL; | |
1050 | cbinfo->host = host; | |
1051 | ||
1052 | SSL_load_error_strings(); /* basic set up */ | |
1053 | OpenSSL_add_ssl_algorithms(); | |
1054 | ||
1055 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
1056 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
1057 | list of available digests. */ | |
1058 | EVP_add_digest(EVP_sha256()); | |
1059 | #endif | |
1060 | ||
1061 | /* Create a context. | |
1062 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1063 | negotiation in the different methods; as far as I can tell, the only | |
1064 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1065 | when OpenSSL is built without SSLv2 support. | |
1066 | By disabling with openssl_options, we can let admins re-enable with the | |
1067 | existing knob. */ | |
1068 | ||
1069 | *ctxp = SSL_CTX_new((host == NULL)? | |
1070 | SSLv23_server_method() : SSLv23_client_method()); | |
1071 | ||
1072 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); | |
1073 | ||
1074 | /* It turns out that we need to seed the random number generator this early in | |
1075 | order to get the full complement of ciphers to work. It took me roughly a day | |
1076 | of work to discover this by experiment. | |
1077 | ||
1078 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1079 | there. Otherwise, we have to make something up as best we can. Double check | |
1080 | afterwards. */ | |
1081 | ||
1082 | if (!RAND_status()) | |
1083 | { | |
1084 | randstuff r; | |
1085 | gettimeofday(&r.tv, NULL); | |
1086 | r.p = getpid(); | |
1087 | ||
1088 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1089 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1090 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1091 | ||
1092 | if (!RAND_status()) | |
1093 | return tls_error(US"RAND_status", host, | |
1094 | US"unable to seed random number generator"); | |
1095 | } | |
1096 | ||
1097 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1098 | level. */ | |
1099 | ||
1100 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); | |
1101 | ||
1102 | /* Automatically re-try reads/writes after renegotiation. */ | |
1103 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); | |
1104 | ||
1105 | /* Apply administrator-supplied work-arounds. | |
1106 | Historically we applied just one requested option, | |
1107 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1108 | moved to an administrator-controlled list of options to specify and | |
1109 | grandfathered in the first one as the default value for "openssl_options". | |
1110 | ||
1111 | No OpenSSL version number checks: the options we accept depend upon the | |
1112 | availability of the option value macros from OpenSSL. */ | |
1113 | ||
1114 | okay = tls_openssl_options_parse(openssl_options, &init_options); | |
1115 | if (!okay) | |
1116 | return tls_error(US"openssl_options parsing failed", host, NULL); | |
1117 | ||
1118 | if (init_options) | |
1119 | { | |
1120 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
1121 | if (!(SSL_CTX_set_options(*ctxp, init_options))) | |
1122 | return tls_error(string_sprintf( | |
1123 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1124 | } | |
1125 | else | |
1126 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
1127 | ||
1128 | /* Initialize with DH parameters if supplied */ | |
1129 | ||
1130 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; | |
1131 | ||
1132 | /* Set up certificate and key (and perhaps OCSP info) */ | |
1133 | ||
1134 | rc = tls_expand_session_files(*ctxp, cbinfo); | |
1135 | if (rc != OK) return rc; | |
1136 | ||
1137 | /* If we need to handle SNI, do so */ | |
1138 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT | |
1139 | if (host == NULL) /* server */ | |
1140 | { | |
1141 | # ifndef DISABLE_OCSP | |
1142 | /* We check u_ocsp.server.file, not server.response, because we care about if | |
1143 | the option exists, not what the current expansion might be, as SNI might | |
1144 | change the certificate and OCSP file in use between now and the time the | |
1145 | callback is invoked. */ | |
1146 | if (cbinfo->u_ocsp.server.file) | |
1147 | { | |
1148 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); | |
1149 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); | |
1150 | } | |
1151 | # endif | |
1152 | /* We always do this, so that $tls_sni is available even if not used in | |
1153 | tls_certificate */ | |
1154 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); | |
1155 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
1156 | } | |
1157 | # ifndef DISABLE_OCSP | |
1158 | else /* client */ | |
1159 | if(ocsp_file) /* wanting stapling */ | |
1160 | { | |
1161 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1162 | { | |
1163 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1164 | return FAIL; | |
1165 | } | |
1166 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1167 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1168 | } | |
1169 | # endif | |
1170 | #endif | |
1171 | ||
1172 | #ifdef EXPERIMENTAL_CERTNAMES | |
1173 | cbinfo->verify_cert_hostnames = NULL; | |
1174 | #endif | |
1175 | ||
1176 | /* Set up the RSA callback */ | |
1177 | ||
1178 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); | |
1179 | ||
1180 | /* Finally, set the timeout, and we are done */ | |
1181 | ||
1182 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); | |
1183 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); | |
1184 | ||
1185 | *cbp = cbinfo; | |
1186 | ||
1187 | return OK; | |
1188 | } | |
1189 | ||
1190 | ||
1191 | ||
1192 | ||
1193 | /************************************************* | |
1194 | * Get name of cipher in use * | |
1195 | *************************************************/ | |
1196 | ||
1197 | /* | |
1198 | Argument: pointer to an SSL structure for the connection | |
1199 | buffer to use for answer | |
1200 | size of buffer | |
1201 | pointer to number of bits for cipher | |
1202 | Returns: nothing | |
1203 | */ | |
1204 | ||
1205 | static void | |
1206 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) | |
1207 | { | |
1208 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't | |
1209 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1210 | the accessor functions use const in the prototype. */ | |
1211 | const SSL_CIPHER *c; | |
1212 | const uschar *ver; | |
1213 | ||
1214 | ver = (const uschar *)SSL_get_version(ssl); | |
1215 | ||
1216 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); | |
1217 | SSL_CIPHER_get_bits(c, bits); | |
1218 | ||
1219 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, | |
1220 | SSL_CIPHER_get_name(c), *bits); | |
1221 | ||
1222 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1223 | } | |
1224 | ||
1225 | ||
1226 | ||
1227 | ||
1228 | ||
1229 | /************************************************* | |
1230 | * Set up for verifying certificates * | |
1231 | *************************************************/ | |
1232 | ||
1233 | /* Called by both client and server startup | |
1234 | ||
1235 | Arguments: | |
1236 | sctx SSL_CTX* to initialise | |
1237 | certs certs file or NULL | |
1238 | crl CRL file or NULL | |
1239 | host NULL in a server; the remote host in a client | |
1240 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1241 | otherwise passed as FALSE | |
1242 | cert_vfy_cb Callback function for certificate verification | |
1243 | ||
1244 | Returns: OK/DEFER/FAIL | |
1245 | */ | |
1246 | ||
1247 | static int | |
1248 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, | |
1249 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ) | |
1250 | { | |
1251 | uschar *expcerts, *expcrl; | |
1252 | ||
1253 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1254 | return DEFER; | |
1255 | ||
1256 | if (expcerts != NULL && *expcerts != '\0') | |
1257 | { | |
1258 | struct stat statbuf; | |
1259 | if (!SSL_CTX_set_default_verify_paths(sctx)) | |
1260 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); | |
1261 | ||
1262 | if (Ustat(expcerts, &statbuf) < 0) | |
1263 | { | |
1264 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1265 | "failed to stat %s for certificates", expcerts); | |
1266 | return DEFER; | |
1267 | } | |
1268 | else | |
1269 | { | |
1270 | uschar *file, *dir; | |
1271 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1272 | { file = NULL; dir = expcerts; } | |
1273 | else | |
1274 | { file = expcerts; dir = NULL; } | |
1275 | ||
1276 | /* If a certificate file is empty, the next function fails with an | |
1277 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1278 | certificates are recognized, but the error message is still misleading (it | |
1279 | says no certificate was supplied.) But this is better. */ | |
1280 | ||
1281 | if ((file == NULL || statbuf.st_size > 0) && | |
1282 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
1283 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); | |
1284 | ||
1285 | if (file != NULL) | |
1286 | { | |
1287 | SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); | |
1288 | } | |
1289 | } | |
1290 | ||
1291 | /* Handle a certificate revocation list. */ | |
1292 | ||
1293 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1294 | ||
1295 | /* This bit of code is now the version supplied by Lars Mainka. (I have | |
1296 | * merely reformatted it into the Exim code style.) | |
1297 | ||
1298 | * "From here I changed the code to add support for multiple crl's | |
1299 | * in pem format in one file or to support hashed directory entries in | |
1300 | * pem format instead of a file. This method now uses the library function | |
1301 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1302 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1303 | * itself in the verify callback." */ | |
1304 | ||
1305 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; | |
1306 | if (expcrl != NULL && *expcrl != 0) | |
1307 | { | |
1308 | struct stat statbufcrl; | |
1309 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1310 | { | |
1311 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1312 | "failed to stat %s for certificates revocation lists", expcrl); | |
1313 | return DEFER; | |
1314 | } | |
1315 | else | |
1316 | { | |
1317 | /* is it a file or directory? */ | |
1318 | uschar *file, *dir; | |
1319 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); | |
1320 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) | |
1321 | { | |
1322 | file = NULL; | |
1323 | dir = expcrl; | |
1324 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
1325 | } | |
1326 | else | |
1327 | { | |
1328 | file = expcrl; | |
1329 | dir = NULL; | |
1330 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
1331 | } | |
1332 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) | |
1333 | return tls_error(US"X509_STORE_load_locations", host, NULL); | |
1334 | ||
1335 | /* setting the flags to check against the complete crl chain */ | |
1336 | ||
1337 | X509_STORE_set_flags(cvstore, | |
1338 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
1339 | } | |
1340 | } | |
1341 | ||
1342 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1343 | ||
1344 | /* If verification is optional, don't fail if no certificate */ | |
1345 | ||
1346 | SSL_CTX_set_verify(sctx, | |
1347 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), | |
1348 | cert_vfy_cb); | |
1349 | } | |
1350 | ||
1351 | return OK; | |
1352 | } | |
1353 | ||
1354 | ||
1355 | ||
1356 | /************************************************* | |
1357 | * Start a TLS session in a server * | |
1358 | *************************************************/ | |
1359 | ||
1360 | /* This is called when Exim is running as a server, after having received | |
1361 | the STARTTLS command. It must respond to that command, and then negotiate | |
1362 | a TLS session. | |
1363 | ||
1364 | Arguments: | |
1365 | require_ciphers allowed ciphers | |
1366 | ||
1367 | Returns: OK on success | |
1368 | DEFER for errors before the start of the negotiation | |
1369 | FAIL for errors during the negotation; the server can't | |
1370 | continue running. | |
1371 | */ | |
1372 | ||
1373 | int | |
1374 | tls_server_start(const uschar *require_ciphers) | |
1375 | { | |
1376 | int rc; | |
1377 | uschar *expciphers; | |
1378 | tls_ext_ctx_cb *cbinfo; | |
1379 | static uschar cipherbuf[256]; | |
1380 | ||
1381 | /* Check for previous activation */ | |
1382 | ||
1383 | if (tls_in.active >= 0) | |
1384 | { | |
1385 | tls_error(US"STARTTLS received after TLS started", NULL, US""); | |
1386 | smtp_printf("554 Already in TLS\r\n"); | |
1387 | return FAIL; | |
1388 | } | |
1389 | ||
1390 | /* Initialize the SSL library. If it fails, it will already have logged | |
1391 | the error. */ | |
1392 | ||
1393 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, | |
1394 | #ifndef DISABLE_OCSP | |
1395 | tls_ocsp_file, | |
1396 | #endif | |
1397 | NULL, &server_static_cbinfo); | |
1398 | if (rc != OK) return rc; | |
1399 | cbinfo = server_static_cbinfo; | |
1400 | ||
1401 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1402 | return FAIL; | |
1403 | ||
1404 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1405 | were historically separated by underscores. So that I can use either form in my | |
1406 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1407 | */ | |
1408 | ||
1409 | if (expciphers != NULL) | |
1410 | { | |
1411 | uschar *s = expciphers; | |
1412 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1413 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
1414 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) | |
1415 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); | |
1416 | cbinfo->server_cipher_list = expciphers; | |
1417 | } | |
1418 | ||
1419 | /* If this is a host for which certificate verification is mandatory or | |
1420 | optional, set up appropriately. */ | |
1421 | ||
1422 | tls_in.certificate_verified = FALSE; | |
1423 | server_verify_callback_called = FALSE; | |
1424 | ||
1425 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1426 | { | |
1427 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, | |
1428 | FALSE, verify_callback_server); | |
1429 | if (rc != OK) return rc; | |
1430 | server_verify_optional = FALSE; | |
1431 | } | |
1432 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1433 | { | |
1434 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, | |
1435 | TRUE, verify_callback_server); | |
1436 | if (rc != OK) return rc; | |
1437 | server_verify_optional = TRUE; | |
1438 | } | |
1439 | ||
1440 | /* Prepare for new connection */ | |
1441 | ||
1442 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); | |
1443 | ||
1444 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1445 | * | |
1446 | * With the SSL_clear(), we get strange interoperability bugs with | |
1447 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1448 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1449 | * | |
1450 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1451 | * session shutdown. In this case, we have a brand new object and there's no | |
1452 | * obvious reason to immediately clear it. I'm guessing that this was | |
1453 | * originally added because of incomplete initialisation which the clear fixed, | |
1454 | * in some historic release. | |
1455 | */ | |
1456 | ||
1457 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1458 | on connection, where outputting anything now upsets the clients and tends to | |
1459 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1460 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1461 | mode, the fflush() happens when smtp_getc() is called. */ | |
1462 | ||
1463 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); | |
1464 | if (!tls_in.on_connect) | |
1465 | { | |
1466 | smtp_printf("220 TLS go ahead\r\n"); | |
1467 | fflush(smtp_out); | |
1468 | } | |
1469 | ||
1470 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1471 | that the OpenSSL library doesn't. */ | |
1472 | ||
1473 | SSL_set_wfd(server_ssl, fileno(smtp_out)); | |
1474 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1475 | SSL_set_accept_state(server_ssl); | |
1476 | ||
1477 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1478 | ||
1479 | sigalrm_seen = FALSE; | |
1480 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1481 | rc = SSL_accept(server_ssl); | |
1482 | alarm(0); | |
1483 | ||
1484 | if (rc <= 0) | |
1485 | { | |
1486 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); | |
1487 | if (ERR_get_error() == 0) | |
1488 | log_write(0, LOG_MAIN, | |
1489 | "TLS client disconnected cleanly (rejected our certificate?)"); | |
1490 | return FAIL; | |
1491 | } | |
1492 | ||
1493 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1494 | ||
1495 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1496 | and initialize things. */ | |
1497 | ||
1498 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); | |
1499 | tls_in.cipher = cipherbuf; | |
1500 | ||
1501 | DEBUG(D_tls) | |
1502 | { | |
1503 | uschar buf[2048]; | |
1504 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) | |
1505 | debug_printf("Shared ciphers: %s\n", buf); | |
1506 | } | |
1507 | ||
1508 | /* Record the certificate we presented */ | |
1509 | { | |
1510 | X509 * crt = SSL_get_certificate(server_ssl); | |
1511 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
1512 | } | |
1513 | ||
1514 | /* Only used by the server-side tls (tls_in), including tls_getc. | |
1515 | Client-side (tls_out) reads (seem to?) go via | |
1516 | smtp_read_response()/ip_recv(). | |
1517 | Hence no need to duplicate for _in and _out. | |
1518 | */ | |
1519 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); | |
1520 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1521 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1522 | ||
1523 | receive_getc = tls_getc; | |
1524 | receive_ungetc = tls_ungetc; | |
1525 | receive_feof = tls_feof; | |
1526 | receive_ferror = tls_ferror; | |
1527 | receive_smtp_buffered = tls_smtp_buffered; | |
1528 | ||
1529 | tls_in.active = fileno(smtp_out); | |
1530 | return OK; | |
1531 | } | |
1532 | ||
1533 | ||
1534 | ||
1535 | ||
1536 | ||
1537 | /************************************************* | |
1538 | * Start a TLS session in a client * | |
1539 | *************************************************/ | |
1540 | ||
1541 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1542 | ||
1543 | Argument: | |
1544 | fd the fd of the connection | |
1545 | host connected host (for messages) | |
1546 | addr the first address | |
1547 | ob smtp transport options | |
1548 | ||
1549 | Returns: OK on success | |
1550 | FAIL otherwise - note that tls_error() will not give DEFER | |
1551 | because this is not a server | |
1552 | */ | |
1553 | ||
1554 | int | |
1555 | tls_client_start(int fd, host_item *host, address_item *addr, | |
1556 | void *v_ob) | |
1557 | { | |
1558 | smtp_transport_options_block * ob = v_ob; | |
1559 | static uschar txt[256]; | |
1560 | uschar *expciphers; | |
1561 | X509* server_cert; | |
1562 | int rc; | |
1563 | static uschar cipherbuf[256]; | |
1564 | #ifndef DISABLE_OCSP | |
1565 | BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, | |
1566 | NULL, host->name, host->address, NULL) == OK; | |
1567 | BOOL request_ocsp = require_ocsp ? TRUE | |
1568 | : verify_check_this_host(&ob->hosts_request_ocsp, | |
1569 | NULL, host->name, host->address, NULL) == OK; | |
1570 | #endif | |
1571 | ||
1572 | rc = tls_init(&client_ctx, host, NULL, | |
1573 | ob->tls_certificate, ob->tls_privatekey, | |
1574 | #ifndef DISABLE_OCSP | |
1575 | (void *)(long)request_ocsp, | |
1576 | #endif | |
1577 | addr, &client_static_cbinfo); | |
1578 | if (rc != OK) return rc; | |
1579 | ||
1580 | tls_out.certificate_verified = FALSE; | |
1581 | client_verify_callback_called = FALSE; | |
1582 | ||
1583 | if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", | |
1584 | &expciphers)) | |
1585 | return FAIL; | |
1586 | ||
1587 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1588 | are separated by underscores. So that I can use either form in my tests, and | |
1589 | also for general convenience, we turn underscores into hyphens here. */ | |
1590 | ||
1591 | if (expciphers != NULL) | |
1592 | { | |
1593 | uschar *s = expciphers; | |
1594 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1595 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
1596 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) | |
1597 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); | |
1598 | } | |
1599 | ||
1600 | /* stick to the old behaviour for compatibility if tls_verify_certificates is | |
1601 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only | |
1602 | the specified host patterns if one of them is defined */ | |
1603 | ||
1604 | if ((!ob->tls_verify_hosts && !ob->tls_try_verify_hosts) || | |
1605 | (verify_check_host(&ob->tls_verify_hosts) == OK)) | |
1606 | { | |
1607 | if ((rc = setup_certs(client_ctx, ob->tls_verify_certificates, | |
1608 | ob->tls_crl, host, FALSE, verify_callback_client)) != OK) | |
1609 | return rc; | |
1610 | client_verify_optional = FALSE; | |
1611 | ||
1612 | #ifdef EXPERIMENTAL_CERTNAMES | |
1613 | if (ob->tls_verify_cert_hostnames) | |
1614 | { | |
1615 | if (!expand_check(ob->tls_verify_cert_hostnames, | |
1616 | US"tls_verify_cert_hostnames", | |
1617 | &client_static_cbinfo->verify_cert_hostnames)) | |
1618 | return FAIL; | |
1619 | if (client_static_cbinfo->verify_cert_hostnames) | |
1620 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1621 | client_static_cbinfo->verify_cert_hostnames); | |
1622 | } | |
1623 | #endif | |
1624 | } | |
1625 | else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) | |
1626 | { | |
1627 | if ((rc = setup_certs(client_ctx, ob->tls_verify_certificates, | |
1628 | ob->tls_crl, host, TRUE, verify_callback_client)) != OK) | |
1629 | return rc; | |
1630 | client_verify_optional = TRUE; | |
1631 | } | |
1632 | ||
1633 | if ((client_ssl = SSL_new(client_ctx)) == NULL) | |
1634 | return tls_error(US"SSL_new", host, NULL); | |
1635 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); | |
1636 | SSL_set_fd(client_ssl, fd); | |
1637 | SSL_set_connect_state(client_ssl); | |
1638 | ||
1639 | if (ob->tls_sni) | |
1640 | { | |
1641 | if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni)) | |
1642 | return FAIL; | |
1643 | if (tls_out.sni == NULL) | |
1644 | { | |
1645 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
1646 | } | |
1647 | else if (!Ustrlen(tls_out.sni)) | |
1648 | tls_out.sni = NULL; | |
1649 | else | |
1650 | { | |
1651 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT | |
1652 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); | |
1653 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
1654 | #else | |
1655 | DEBUG(D_tls) | |
1656 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
1657 | tls_out.sni); | |
1658 | #endif | |
1659 | } | |
1660 | } | |
1661 | ||
1662 | #ifndef DISABLE_OCSP | |
1663 | /* Request certificate status at connection-time. If the server | |
1664 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
1665 | if (request_ocsp) | |
1666 | { | |
1667 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); | |
1668 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; | |
1669 | tls_out.ocsp = OCSP_NOT_RESP; | |
1670 | } | |
1671 | #endif | |
1672 | ||
1673 | /* There doesn't seem to be a built-in timeout on connection. */ | |
1674 | ||
1675 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1676 | sigalrm_seen = FALSE; | |
1677 | alarm(ob->command_timeout); | |
1678 | rc = SSL_connect(client_ssl); | |
1679 | alarm(0); | |
1680 | ||
1681 | if (rc <= 0) | |
1682 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); | |
1683 | ||
1684 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1685 | ||
1686 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
1687 | /*XXX server_cert is never freed... use X509_free() */ | |
1688 | server_cert = SSL_get_peer_certificate (client_ssl); | |
1689 | if (server_cert) | |
1690 | { | |
1691 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), | |
1692 | CS txt, sizeof(txt)); | |
1693 | tls_out.peerdn = txt; /*XXX a static buffer... */ | |
1694 | } | |
1695 | else | |
1696 | tls_out.peerdn = NULL; | |
1697 | ||
1698 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); | |
1699 | tls_out.cipher = cipherbuf; | |
1700 | ||
1701 | /* Record the certificate we presented */ | |
1702 | { | |
1703 | X509 * crt = SSL_get_certificate(client_ssl); | |
1704 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
1705 | } | |
1706 | ||
1707 | tls_out.active = fd; | |
1708 | return OK; | |
1709 | } | |
1710 | ||
1711 | ||
1712 | ||
1713 | ||
1714 | ||
1715 | /************************************************* | |
1716 | * TLS version of getc * | |
1717 | *************************************************/ | |
1718 | ||
1719 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1720 | it refills the buffer via the SSL reading function. | |
1721 | ||
1722 | Arguments: none | |
1723 | Returns: the next character or EOF | |
1724 | ||
1725 | Only used by the server-side TLS. | |
1726 | */ | |
1727 | ||
1728 | int | |
1729 | tls_getc(void) | |
1730 | { | |
1731 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1732 | { | |
1733 | int error; | |
1734 | int inbytes; | |
1735 | ||
1736 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, | |
1737 | ssl_xfer_buffer, ssl_xfer_buffer_size); | |
1738 | ||
1739 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1740 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); | |
1741 | error = SSL_get_error(server_ssl, inbytes); | |
1742 | alarm(0); | |
1743 | ||
1744 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
1745 | closed down, not that the socket itself has been closed down. Revert to | |
1746 | non-SSL handling. */ | |
1747 | ||
1748 | if (error == SSL_ERROR_ZERO_RETURN) | |
1749 | { | |
1750 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1751 | ||
1752 | receive_getc = smtp_getc; | |
1753 | receive_ungetc = smtp_ungetc; | |
1754 | receive_feof = smtp_feof; | |
1755 | receive_ferror = smtp_ferror; | |
1756 | receive_smtp_buffered = smtp_buffered; | |
1757 | ||
1758 | SSL_free(server_ssl); | |
1759 | server_ssl = NULL; | |
1760 | tls_in.active = -1; | |
1761 | tls_in.bits = 0; | |
1762 | tls_in.cipher = NULL; | |
1763 | tls_in.peerdn = NULL; | |
1764 | tls_in.sni = NULL; | |
1765 | ||
1766 | return smtp_getc(); | |
1767 | } | |
1768 | ||
1769 | /* Handle genuine errors */ | |
1770 | ||
1771 | else if (error == SSL_ERROR_SSL) | |
1772 | { | |
1773 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1774 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); | |
1775 | ssl_xfer_error = 1; | |
1776 | return EOF; | |
1777 | } | |
1778 | ||
1779 | else if (error != SSL_ERROR_NONE) | |
1780 | { | |
1781 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
1782 | ssl_xfer_error = 1; | |
1783 | return EOF; | |
1784 | } | |
1785 | ||
1786 | #ifndef DISABLE_DKIM | |
1787 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
1788 | #endif | |
1789 | ssl_xfer_buffer_hwm = inbytes; | |
1790 | ssl_xfer_buffer_lwm = 0; | |
1791 | } | |
1792 | ||
1793 | /* Something in the buffer; return next uschar */ | |
1794 | ||
1795 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1796 | } | |
1797 | ||
1798 | ||
1799 | ||
1800 | /************************************************* | |
1801 | * Read bytes from TLS channel * | |
1802 | *************************************************/ | |
1803 | ||
1804 | /* | |
1805 | Arguments: | |
1806 | buff buffer of data | |
1807 | len size of buffer | |
1808 | ||
1809 | Returns: the number of bytes read | |
1810 | -1 after a failed read | |
1811 | ||
1812 | Only used by the client-side TLS. | |
1813 | */ | |
1814 | ||
1815 | int | |
1816 | tls_read(BOOL is_server, uschar *buff, size_t len) | |
1817 | { | |
1818 | SSL *ssl = is_server ? server_ssl : client_ssl; | |
1819 | int inbytes; | |
1820 | int error; | |
1821 | ||
1822 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, | |
1823 | buff, (unsigned int)len); | |
1824 | ||
1825 | inbytes = SSL_read(ssl, CS buff, len); | |
1826 | error = SSL_get_error(ssl, inbytes); | |
1827 | ||
1828 | if (error == SSL_ERROR_ZERO_RETURN) | |
1829 | { | |
1830 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1831 | return -1; | |
1832 | } | |
1833 | else if (error != SSL_ERROR_NONE) | |
1834 | { | |
1835 | return -1; | |
1836 | } | |
1837 | ||
1838 | return inbytes; | |
1839 | } | |
1840 | ||
1841 | ||
1842 | ||
1843 | ||
1844 | ||
1845 | /************************************************* | |
1846 | * Write bytes down TLS channel * | |
1847 | *************************************************/ | |
1848 | ||
1849 | /* | |
1850 | Arguments: | |
1851 | is_server channel specifier | |
1852 | buff buffer of data | |
1853 | len number of bytes | |
1854 | ||
1855 | Returns: the number of bytes after a successful write, | |
1856 | -1 after a failed write | |
1857 | ||
1858 | Used by both server-side and client-side TLS. | |
1859 | */ | |
1860 | ||
1861 | int | |
1862 | tls_write(BOOL is_server, const uschar *buff, size_t len) | |
1863 | { | |
1864 | int outbytes; | |
1865 | int error; | |
1866 | int left = len; | |
1867 | SSL *ssl = is_server ? server_ssl : client_ssl; | |
1868 | ||
1869 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); | |
1870 | while (left > 0) | |
1871 | { | |
1872 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); | |
1873 | outbytes = SSL_write(ssl, CS buff, left); | |
1874 | error = SSL_get_error(ssl, outbytes); | |
1875 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1876 | switch (error) | |
1877 | { | |
1878 | case SSL_ERROR_SSL: | |
1879 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1880 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1881 | return -1; | |
1882 | ||
1883 | case SSL_ERROR_NONE: | |
1884 | left -= outbytes; | |
1885 | buff += outbytes; | |
1886 | break; | |
1887 | ||
1888 | case SSL_ERROR_ZERO_RETURN: | |
1889 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1890 | return -1; | |
1891 | ||
1892 | case SSL_ERROR_SYSCALL: | |
1893 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
1894 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
1895 | strerror(errno)); | |
1896 | ||
1897 | default: | |
1898 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1899 | return -1; | |
1900 | } | |
1901 | } | |
1902 | return len; | |
1903 | } | |
1904 | ||
1905 | ||
1906 | ||
1907 | /************************************************* | |
1908 | * Close down a TLS session * | |
1909 | *************************************************/ | |
1910 | ||
1911 | /* This is also called from within a delivery subprocess forked from the | |
1912 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1913 | would tamper with the SSL session in the parent process). | |
1914 | ||
1915 | Arguments: TRUE if SSL_shutdown is to be called | |
1916 | Returns: nothing | |
1917 | ||
1918 | Used by both server-side and client-side TLS. | |
1919 | */ | |
1920 | ||
1921 | void | |
1922 | tls_close(BOOL is_server, BOOL shutdown) | |
1923 | { | |
1924 | SSL **sslp = is_server ? &server_ssl : &client_ssl; | |
1925 | int *fdp = is_server ? &tls_in.active : &tls_out.active; | |
1926 | ||
1927 | if (*fdp < 0) return; /* TLS was not active */ | |
1928 | ||
1929 | if (shutdown) | |
1930 | { | |
1931 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
1932 | SSL_shutdown(*sslp); | |
1933 | } | |
1934 | ||
1935 | SSL_free(*sslp); | |
1936 | *sslp = NULL; | |
1937 | ||
1938 | *fdp = -1; | |
1939 | } | |
1940 | ||
1941 | ||
1942 | ||
1943 | ||
1944 | /************************************************* | |
1945 | * Let tls_require_ciphers be checked at startup * | |
1946 | *************************************************/ | |
1947 | ||
1948 | /* The tls_require_ciphers option, if set, must be something which the | |
1949 | library can parse. | |
1950 | ||
1951 | Returns: NULL on success, or error message | |
1952 | */ | |
1953 | ||
1954 | uschar * | |
1955 | tls_validate_require_cipher(void) | |
1956 | { | |
1957 | SSL_CTX *ctx; | |
1958 | uschar *s, *expciphers, *err; | |
1959 | ||
1960 | /* this duplicates from tls_init(), we need a better "init just global | |
1961 | state, for no specific purpose" singleton function of our own */ | |
1962 | ||
1963 | SSL_load_error_strings(); | |
1964 | OpenSSL_add_ssl_algorithms(); | |
1965 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
1966 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
1967 | list of available digests. */ | |
1968 | EVP_add_digest(EVP_sha256()); | |
1969 | #endif | |
1970 | ||
1971 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1972 | return NULL; | |
1973 | ||
1974 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1975 | return US"failed to expand tls_require_ciphers"; | |
1976 | ||
1977 | if (!(expciphers && *expciphers)) | |
1978 | return NULL; | |
1979 | ||
1980 | /* normalisation ripped from above */ | |
1981 | s = expciphers; | |
1982 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1983 | ||
1984 | err = NULL; | |
1985 | ||
1986 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
1987 | if (!ctx) | |
1988 | { | |
1989 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1990 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
1991 | } | |
1992 | ||
1993 | DEBUG(D_tls) | |
1994 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1995 | ||
1996 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
1997 | { | |
1998 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1999 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
2000 | } | |
2001 | ||
2002 | SSL_CTX_free(ctx); | |
2003 | ||
2004 | return err; | |
2005 | } | |
2006 | ||
2007 | ||
2008 | ||
2009 | ||
2010 | /************************************************* | |
2011 | * Report the library versions. * | |
2012 | *************************************************/ | |
2013 | ||
2014 | /* There have historically been some issues with binary compatibility in | |
2015 | OpenSSL libraries; if Exim (like many other applications) is built against | |
2016 | one version of OpenSSL but the run-time linker picks up another version, | |
2017 | it can result in serious failures, including crashing with a SIGSEGV. So | |
2018 | report the version found by the compiler and the run-time version. | |
2019 | ||
2020 | Note: some OS vendors backport security fixes without changing the version | |
2021 | number/string, and the version date remains unchanged. The _build_ date | |
2022 | will change, so we can more usefully assist with version diagnosis by also | |
2023 | reporting the build date. | |
2024 | ||
2025 | Arguments: a FILE* to print the results to | |
2026 | Returns: nothing | |
2027 | */ | |
2028 | ||
2029 | void | |
2030 | tls_version_report(FILE *f) | |
2031 | { | |
2032 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" | |
2033 | " Runtime: %s\n" | |
2034 | " : %s\n", | |
2035 | OPENSSL_VERSION_TEXT, | |
2036 | SSLeay_version(SSLEAY_VERSION), | |
2037 | SSLeay_version(SSLEAY_BUILT_ON)); | |
2038 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
2039 | the OpenSSL output includes a "built on: " prefix already. */ | |
2040 | } | |
2041 | ||
2042 | ||
2043 | ||
2044 | ||
2045 | /************************************************* | |
2046 | * Random number generation * | |
2047 | *************************************************/ | |
2048 | ||
2049 | /* Pseudo-random number generation. The result is not expected to be | |
2050 | cryptographically strong but not so weak that someone will shoot themselves | |
2051 | in the foot using it as a nonce in input in some email header scheme or | |
2052 | whatever weirdness they'll twist this into. The result should handle fork() | |
2053 | and avoid repeating sequences. OpenSSL handles that for us. | |
2054 | ||
2055 | Arguments: | |
2056 | max range maximum | |
2057 | Returns a random number in range [0, max-1] | |
2058 | */ | |
2059 | ||
2060 | int | |
2061 | vaguely_random_number(int max) | |
2062 | { | |
2063 | unsigned int r; | |
2064 | int i, needed_len; | |
2065 | static pid_t pidlast = 0; | |
2066 | pid_t pidnow; | |
2067 | uschar *p; | |
2068 | uschar smallbuf[sizeof(r)]; | |
2069 | ||
2070 | if (max <= 1) | |
2071 | return 0; | |
2072 | ||
2073 | pidnow = getpid(); | |
2074 | if (pidnow != pidlast) | |
2075 | { | |
2076 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2077 | is unique for each thread", this doesn't apparently apply across processes, | |
2078 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2079 | Fix per PostgreSQL. */ | |
2080 | if (pidlast != 0) | |
2081 | RAND_cleanup(); | |
2082 | pidlast = pidnow; | |
2083 | } | |
2084 | ||
2085 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ | |
2086 | if (!RAND_status()) | |
2087 | { | |
2088 | randstuff r; | |
2089 | gettimeofday(&r.tv, NULL); | |
2090 | r.p = getpid(); | |
2091 | ||
2092 | RAND_seed((uschar *)(&r), sizeof(r)); | |
2093 | } | |
2094 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2095 | in the internal PRNG then our options are limited. We could sleep and hope | |
2096 | for entropy to come along (prayer technique) but if the system is so depleted | |
2097 | in the first place then something is likely to just keep taking it. Instead, | |
2098 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2099 | get. */ | |
2100 | ||
2101 | needed_len = sizeof(r); | |
2102 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2103 | asked for a number less than 10. */ | |
2104 | for (r = max, i = 0; r; ++i) | |
2105 | r >>= 1; | |
2106 | i = (i + 7) / 8; | |
2107 | if (i < needed_len) | |
2108 | needed_len = i; | |
2109 | ||
2110 | /* We do not care if crypto-strong */ | |
2111 | i = RAND_pseudo_bytes(smallbuf, needed_len); | |
2112 | if (i < 0) | |
2113 | { | |
2114 | DEBUG(D_all) | |
2115 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2116 | return vaguely_random_number_fallback(max); | |
2117 | } | |
2118 | ||
2119 | r = 0; | |
2120 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2121 | { | |
2122 | r *= 256; | |
2123 | r += *p; | |
2124 | } | |
2125 | ||
2126 | /* We don't particularly care about weighted results; if someone wants | |
2127 | smooth distribution and cares enough then they should submit a patch then. */ | |
2128 | return r % max; | |
2129 | } | |
2130 | ||
2131 | ||
2132 | ||
2133 | ||
2134 | /************************************************* | |
2135 | * OpenSSL option parse * | |
2136 | *************************************************/ | |
2137 | ||
2138 | /* Parse one option for tls_openssl_options_parse below | |
2139 | ||
2140 | Arguments: | |
2141 | name one option name | |
2142 | value place to store a value for it | |
2143 | Returns success or failure in parsing | |
2144 | */ | |
2145 | ||
2146 | struct exim_openssl_option { | |
2147 | uschar *name; | |
2148 | long value; | |
2149 | }; | |
2150 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2151 | options document which version they were introduced in. Policylet: include | |
2152 | all options unless explicitly for DTLS, let the administrator choose which | |
2153 | to apply. | |
2154 | ||
2155 | This list is current as of: | |
2156 | ==> 1.0.1b <== | |
2157 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2158 | */ | |
2159 | static struct exim_openssl_option exim_openssl_options[] = { | |
2160 | /* KEEP SORTED ALPHABETICALLY! */ | |
2161 | #ifdef SSL_OP_ALL | |
2162 | { US"all", SSL_OP_ALL }, | |
2163 | #endif | |
2164 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
2165 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, | |
2166 | #endif | |
2167 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
2168 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, | |
2169 | #endif | |
2170 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
2171 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, | |
2172 | #endif | |
2173 | #ifdef SSL_OP_EPHEMERAL_RSA | |
2174 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, | |
2175 | #endif | |
2176 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
2177 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, | |
2178 | #endif | |
2179 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
2180 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, | |
2181 | #endif | |
2182 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
2183 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, | |
2184 | #endif | |
2185 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
2186 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, | |
2187 | #endif | |
2188 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
2189 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, | |
2190 | #endif | |
2191 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
2192 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, | |
2193 | #endif | |
2194 | #ifdef SSL_OP_NO_COMPRESSION | |
2195 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2196 | #endif | |
2197 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION | |
2198 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, | |
2199 | #endif | |
2200 | #ifdef SSL_OP_NO_SSLv2 | |
2201 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2202 | #endif | |
2203 | #ifdef SSL_OP_NO_SSLv3 | |
2204 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2205 | #endif | |
2206 | #ifdef SSL_OP_NO_TICKET | |
2207 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2208 | #endif | |
2209 | #ifdef SSL_OP_NO_TLSv1 | |
2210 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2211 | #endif | |
2212 | #ifdef SSL_OP_NO_TLSv1_1 | |
2213 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2214 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2215 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2216 | #else | |
2217 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2218 | #endif | |
2219 | #endif | |
2220 | #ifdef SSL_OP_NO_TLSv1_2 | |
2221 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2222 | #endif | |
2223 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG | |
2224 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2225 | #endif | |
2226 | #ifdef SSL_OP_SINGLE_DH_USE | |
2227 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, | |
2228 | #endif | |
2229 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
2230 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, | |
2231 | #endif | |
2232 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
2233 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, | |
2234 | #endif | |
2235 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
2236 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, | |
2237 | #endif | |
2238 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
2239 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, | |
2240 | #endif | |
2241 | #ifdef SSL_OP_TLS_D5_BUG | |
2242 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, | |
2243 | #endif | |
2244 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
2245 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, | |
2246 | #endif | |
2247 | }; | |
2248 | static int exim_openssl_options_size = | |
2249 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2250 | ||
2251 | ||
2252 | static BOOL | |
2253 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2254 | { | |
2255 | int first = 0; | |
2256 | int last = exim_openssl_options_size; | |
2257 | while (last > first) | |
2258 | { | |
2259 | int middle = (first + last)/2; | |
2260 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2261 | if (c == 0) | |
2262 | { | |
2263 | *value = exim_openssl_options[middle].value; | |
2264 | return TRUE; | |
2265 | } | |
2266 | else if (c > 0) | |
2267 | first = middle + 1; | |
2268 | else | |
2269 | last = middle; | |
2270 | } | |
2271 | return FALSE; | |
2272 | } | |
2273 | ||
2274 | ||
2275 | ||
2276 | ||
2277 | /************************************************* | |
2278 | * OpenSSL option parsing logic * | |
2279 | *************************************************/ | |
2280 | ||
2281 | /* OpenSSL has a number of compatibility options which an administrator might | |
2282 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2283 | we look like log_selector. | |
2284 | ||
2285 | Arguments: | |
2286 | option_spec the administrator-supplied string of options | |
2287 | results ptr to long storage for the options bitmap | |
2288 | Returns success or failure | |
2289 | */ | |
2290 | ||
2291 | BOOL | |
2292 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2293 | { | |
2294 | long result, item; | |
2295 | uschar *s, *end; | |
2296 | uschar keep_c; | |
2297 | BOOL adding, item_parsed; | |
2298 | ||
2299 | result = 0L; | |
2300 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed | |
2301 | * from default because it increases BEAST susceptibility. */ | |
2302 | #ifdef SSL_OP_NO_SSLv2 | |
2303 | result |= SSL_OP_NO_SSLv2; | |
2304 | #endif | |
2305 | ||
2306 | if (option_spec == NULL) | |
2307 | { | |
2308 | *results = result; | |
2309 | return TRUE; | |
2310 | } | |
2311 | ||
2312 | for (s=option_spec; *s != '\0'; /**/) | |
2313 | { | |
2314 | while (isspace(*s)) ++s; | |
2315 | if (*s == '\0') | |
2316 | break; | |
2317 | if (*s != '+' && *s != '-') | |
2318 | { | |
2319 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
2320 | "+ or - expected but found \"%s\"\n", s); | |
2321 | return FALSE; | |
2322 | } | |
2323 | adding = *s++ == '+'; | |
2324 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2325 | keep_c = *end; | |
2326 | *end = '\0'; | |
2327 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2328 | if (!item_parsed) | |
2329 | { | |
2330 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); | |
2331 | return FALSE; | |
2332 | } | |
2333 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2334 | adding ? "adding" : "removing", result, item, s); | |
2335 | if (adding) | |
2336 | result |= item; | |
2337 | else | |
2338 | result &= ~item; | |
2339 | *end = keep_c; | |
2340 | s = end; | |
2341 | } | |
2342 | ||
2343 | *results = result; | |
2344 | return TRUE; | |
2345 | } | |
2346 | ||
2347 | /* vi: aw ai sw=2 | |
2348 | */ | |
2349 | /* End of tls-openssl.c */ |