Commit | Line | Data |
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059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
0a49a7a4 | 5 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
8 | /* This module provides the TLS (aka SSL) support for Exim using the OpenSSL | |
9 | library. It is #included into the tls.c file when that library is used. The | |
10 | code herein is based on a patch that was originally contributed by Steve | |
11 | Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara. | |
12 | ||
13 | No cryptographic code is included in Exim. All this module does is to call | |
14 | functions from the OpenSSL library. */ | |
15 | ||
16 | ||
17 | /* Heading stuff */ | |
18 | ||
19 | #include <openssl/lhash.h> | |
20 | #include <openssl/ssl.h> | |
21 | #include <openssl/err.h> | |
22 | #include <openssl/rand.h> | |
3f7eeb86 PP |
23 | #ifdef EXPERIMENTAL_OCSP |
24 | #include <openssl/ocsp.h> | |
25 | #endif | |
26 | ||
27 | #ifdef EXPERIMENTAL_OCSP | |
28 | #define EXIM_OCSP_SKEW_SECONDS (300L) | |
29 | #define EXIM_OCSP_MAX_AGE (-1L) | |
30 | #endif | |
059ec3d9 PH |
31 | |
32 | /* Structure for collecting random data for seeding. */ | |
33 | ||
34 | typedef struct randstuff { | |
9e3331ea TK |
35 | struct timeval tv; |
36 | pid_t p; | |
059ec3d9 PH |
37 | } randstuff; |
38 | ||
39 | /* Local static variables */ | |
40 | ||
41 | static BOOL verify_callback_called = FALSE; | |
42 | static const uschar *sid_ctx = US"exim"; | |
43 | ||
44 | static SSL_CTX *ctx = NULL; | |
7be682ca | 45 | static SSL_CTX *ctx_sni = NULL; |
059ec3d9 PH |
46 | static SSL *ssl = NULL; |
47 | ||
48 | static char ssl_errstring[256]; | |
49 | ||
50 | static int ssl_session_timeout = 200; | |
51 | static BOOL verify_optional = FALSE; | |
52 | ||
7be682ca | 53 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
54 | |
55 | ||
7be682ca PP |
56 | typedef struct tls_ext_ctx_cb { |
57 | uschar *certificate; | |
58 | uschar *privatekey; | |
3f7eeb86 PP |
59 | #ifdef EXPERIMENTAL_OCSP |
60 | uschar *ocsp_file; | |
61 | uschar *ocsp_file_expanded; | |
62 | OCSP_RESPONSE *ocsp_response; | |
63 | #endif | |
7be682ca PP |
64 | uschar *dhparam; |
65 | /* these are cached from first expand */ | |
66 | uschar *server_cipher_list; | |
67 | /* only passed down to tls_error: */ | |
68 | host_item *host; | |
69 | } tls_ext_ctx_cb; | |
70 | ||
71 | /* should figure out a cleanup of API to handle state preserved per | |
72 | implementation, for various reasons, which can be void * in the APIs. | |
73 | For now, we hack around it. */ | |
74 | tls_ext_ctx_cb *static_cbinfo = NULL; | |
75 | ||
76 | static int | |
77 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional); | |
059ec3d9 | 78 | |
3f7eeb86 PP |
79 | /* Callbacks */ |
80 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); | |
81 | #ifdef EXPERIMENTAL_OCSP | |
82 | static int tls_stapling_cb(SSL *s, void *arg); | |
83 | #endif | |
84 | ||
059ec3d9 PH |
85 | |
86 | /************************************************* | |
87 | * Handle TLS error * | |
88 | *************************************************/ | |
89 | ||
90 | /* Called from lots of places when errors occur before actually starting to do | |
91 | the TLS handshake, that is, while the session is still in clear. Always returns | |
92 | DEFER for a server and FAIL for a client so that most calls can use "return | |
93 | tls_error(...)" to do this processing and then give an appropriate return. A | |
94 | single function is used for both server and client, because it is called from | |
95 | some shared functions. | |
96 | ||
97 | Argument: | |
98 | prefix text to include in the logged error | |
99 | host NULL if setting up a server; | |
100 | the connected host if setting up a client | |
7199e1ee | 101 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
102 | |
103 | Returns: OK/DEFER/FAIL | |
104 | */ | |
105 | ||
106 | static int | |
7199e1ee | 107 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 108 | { |
7199e1ee TF |
109 | if (msg == NULL) |
110 | { | |
111 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 112 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
113 | } |
114 | ||
059ec3d9 PH |
115 | if (host == NULL) |
116 | { | |
7199e1ee | 117 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 118 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
119 | conn_info += 5; |
120 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
121 | conn_info, prefix, msg); | |
059ec3d9 PH |
122 | return DEFER; |
123 | } | |
124 | else | |
125 | { | |
126 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
7199e1ee | 127 | host->name, host->address, prefix, msg); |
059ec3d9 PH |
128 | return FAIL; |
129 | } | |
130 | } | |
131 | ||
132 | ||
133 | ||
134 | /************************************************* | |
135 | * Callback to generate RSA key * | |
136 | *************************************************/ | |
137 | ||
138 | /* | |
139 | Arguments: | |
140 | s SSL connection | |
141 | export not used | |
142 | keylength keylength | |
143 | ||
144 | Returns: pointer to generated key | |
145 | */ | |
146 | ||
147 | static RSA * | |
148 | rsa_callback(SSL *s, int export, int keylength) | |
149 | { | |
150 | RSA *rsa_key; | |
151 | export = export; /* Shut picky compilers up */ | |
152 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
153 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
154 | if (rsa_key == NULL) | |
155 | { | |
156 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
157 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
158 | ssl_errstring); | |
159 | return NULL; | |
160 | } | |
161 | return rsa_key; | |
162 | } | |
163 | ||
164 | ||
165 | ||
166 | ||
167 | /************************************************* | |
168 | * Callback for verification * | |
169 | *************************************************/ | |
170 | ||
171 | /* The SSL library does certificate verification if set up to do so. This | |
172 | callback has the current yes/no state is in "state". If verification succeeded, | |
173 | we set up the tls_peerdn string. If verification failed, what happens depends | |
174 | on whether the client is required to present a verifiable certificate or not. | |
175 | ||
176 | If verification is optional, we change the state to yes, but still log the | |
177 | verification error. For some reason (it really would help to have proper | |
178 | documentation of OpenSSL), this callback function then gets called again, this | |
179 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
180 | value, but we must take care not to set the private verified flag on the second | |
181 | time through. | |
182 | ||
183 | Note: this function is not called if the client fails to present a certificate | |
184 | when asked. We get here only if a certificate has been received. Handling of | |
185 | optional verification for this case is done when requesting SSL to verify, by | |
186 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
187 | ||
188 | Arguments: | |
189 | state current yes/no state as 1/0 | |
190 | x509ctx certificate information. | |
191 | ||
192 | Returns: 1 if verified, 0 if not | |
193 | */ | |
194 | ||
195 | static int | |
196 | verify_callback(int state, X509_STORE_CTX *x509ctx) | |
197 | { | |
198 | static uschar txt[256]; | |
199 | ||
200 | X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert), | |
201 | CS txt, sizeof(txt)); | |
202 | ||
203 | if (state == 0) | |
204 | { | |
205 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
206 | x509ctx->error_depth, | |
207 | X509_verify_cert_error_string(x509ctx->error), | |
208 | txt); | |
209 | tls_certificate_verified = FALSE; | |
210 | verify_callback_called = TRUE; | |
211 | if (!verify_optional) return 0; /* reject */ | |
212 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " | |
213 | "tls_try_verify_hosts)\n"); | |
214 | return 1; /* accept */ | |
215 | } | |
216 | ||
217 | if (x509ctx->error_depth != 0) | |
218 | { | |
219 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n", | |
220 | x509ctx->error_depth, txt); | |
221 | } | |
222 | else | |
223 | { | |
224 | DEBUG(D_tls) debug_printf("SSL%s peer: %s\n", | |
225 | verify_callback_called? "" : " authenticated", txt); | |
226 | tls_peerdn = txt; | |
227 | } | |
228 | ||
059ec3d9 PH |
229 | if (!verify_callback_called) tls_certificate_verified = TRUE; |
230 | verify_callback_called = TRUE; | |
231 | ||
232 | return 1; /* accept */ | |
233 | } | |
234 | ||
235 | ||
236 | ||
237 | /************************************************* | |
238 | * Information callback * | |
239 | *************************************************/ | |
240 | ||
241 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
242 | are doing. We copy the string to the debugging output when TLS debugging has |
243 | been requested. | |
059ec3d9 PH |
244 | |
245 | Arguments: | |
246 | s the SSL connection | |
247 | where | |
248 | ret | |
249 | ||
250 | Returns: nothing | |
251 | */ | |
252 | ||
253 | static void | |
254 | info_callback(SSL *s, int where, int ret) | |
255 | { | |
256 | where = where; | |
257 | ret = ret; | |
258 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
259 | } | |
260 | ||
261 | ||
262 | ||
263 | /************************************************* | |
264 | * Initialize for DH * | |
265 | *************************************************/ | |
266 | ||
267 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
268 | ||
269 | Arguments: | |
270 | dhparam DH parameter file | |
7199e1ee | 271 | host connected host, if client; NULL if server |
059ec3d9 PH |
272 | |
273 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
274 | */ | |
275 | ||
276 | static BOOL | |
7199e1ee | 277 | init_dh(uschar *dhparam, host_item *host) |
059ec3d9 PH |
278 | { |
279 | BOOL yield = TRUE; | |
280 | BIO *bio; | |
281 | DH *dh; | |
282 | uschar *dhexpanded; | |
283 | ||
284 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
285 | return FALSE; | |
286 | ||
287 | if (dhexpanded == NULL) return TRUE; | |
288 | ||
289 | if ((bio = BIO_new_file(CS dhexpanded, "r")) == NULL) | |
290 | { | |
7199e1ee | 291 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
5ca6d115 | 292 | host, (uschar *)strerror(errno)); |
059ec3d9 PH |
293 | yield = FALSE; |
294 | } | |
295 | else | |
296 | { | |
297 | if ((dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)) == NULL) | |
298 | { | |
7199e1ee TF |
299 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
300 | host, NULL); | |
059ec3d9 PH |
301 | yield = FALSE; |
302 | } | |
303 | else | |
304 | { | |
305 | SSL_CTX_set_tmp_dh(ctx, dh); | |
306 | DEBUG(D_tls) | |
307 | debug_printf("Diffie-Hellman initialized from %s with %d-bit key\n", | |
308 | dhexpanded, 8*DH_size(dh)); | |
309 | DH_free(dh); | |
310 | } | |
311 | BIO_free(bio); | |
312 | } | |
313 | ||
314 | return yield; | |
315 | } | |
316 | ||
317 | ||
318 | ||
319 | ||
3f7eeb86 PP |
320 | #ifdef EXPERIMENTAL_OCSP |
321 | /************************************************* | |
322 | * Load OCSP information into state * | |
323 | *************************************************/ | |
324 | ||
325 | /* Called to load the OCSP response from the given file into memory, once | |
326 | caller has determined this is needed. Checks validity. Debugs a message | |
327 | if invalid. | |
328 | ||
329 | ASSUMES: single response, for single cert. | |
330 | ||
331 | Arguments: | |
332 | sctx the SSL_CTX* to update | |
333 | cbinfo various parts of session state | |
334 | expanded the filename putatively holding an OCSP response | |
335 | ||
336 | */ | |
337 | ||
338 | static void | |
339 | ocsp_load_response(SSL_CTX *sctx, | |
340 | tls_ext_ctx_cb *cbinfo, | |
341 | const uschar *expanded) | |
342 | { | |
343 | BIO *bio; | |
344 | OCSP_RESPONSE *resp; | |
345 | OCSP_BASICRESP *basic_response; | |
346 | OCSP_SINGLERESP *single_response; | |
347 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
348 | X509_STORE *store; | |
349 | unsigned long verify_flags; | |
350 | int status, reason, i; | |
351 | ||
352 | cbinfo->ocsp_file_expanded = string_copy(expanded); | |
353 | if (cbinfo->ocsp_response) | |
354 | { | |
355 | OCSP_RESPONSE_free(cbinfo->ocsp_response); | |
356 | cbinfo->ocsp_response = NULL; | |
357 | } | |
358 | ||
359 | bio = BIO_new_file(CS cbinfo->ocsp_file_expanded, "rb"); | |
360 | if (!bio) | |
361 | { | |
362 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
363 | cbinfo->ocsp_file_expanded); | |
364 | return; | |
365 | } | |
366 | ||
367 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
368 | BIO_free(bio); | |
369 | if (!resp) | |
370 | { | |
371 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
372 | return; | |
373 | } | |
374 | ||
375 | status = OCSP_response_status(resp); | |
376 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
377 | { | |
378 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
379 | OCSP_response_status_str(status), status); | |
380 | return; | |
381 | } | |
382 | ||
383 | basic_response = OCSP_response_get1_basic(resp); | |
384 | if (!basic_response) | |
385 | { | |
386 | DEBUG(D_tls) | |
387 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
388 | return; | |
389 | } | |
390 | ||
391 | store = SSL_CTX_get_cert_store(sctx); | |
392 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
393 | ||
394 | /* May need to expose ability to adjust those flags? | |
395 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
396 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
397 | ||
398 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
399 | if (i <= 0) | |
400 | { | |
401 | DEBUG(D_tls) { | |
402 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
403 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
404 | } | |
405 | return; | |
406 | } | |
407 | ||
408 | /* Here's the simplifying assumption: there's only one response, for the | |
409 | one certificate we use, and nothing for anything else in a chain. If this | |
410 | proves false, we need to extract a cert id from our issued cert | |
411 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
412 | right cert in the stack and then calls OCSP_single_get0_status()). | |
413 | ||
414 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
415 | single_response = OCSP_resp_get0(basic_response, 0); | |
416 | if (!single_response) | |
417 | { | |
418 | DEBUG(D_tls) | |
419 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
420 | return; | |
421 | } | |
422 | ||
423 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
424 | /* how does this status differ from the one above? */ | |
425 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
426 | { | |
427 | DEBUG(D_tls) debug_printf("OCSP response not valid (take 2): %s (%d)\n", | |
428 | OCSP_response_status_str(status), status); | |
429 | return; | |
430 | } | |
431 | ||
432 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
433 | { | |
434 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
435 | return; | |
436 | } | |
437 | ||
438 | cbinfo->ocsp_response = resp; | |
439 | } | |
440 | #endif | |
441 | ||
442 | ||
443 | ||
444 | ||
7be682ca PP |
445 | /************************************************* |
446 | * Expand key and cert file specs * | |
447 | *************************************************/ | |
448 | ||
449 | /* Called once during tls_init and possibly againt during TLS setup, for a | |
450 | new context, if Server Name Indication was used and tls_sni was seen in | |
451 | the certificate string. | |
452 | ||
453 | Arguments: | |
454 | sctx the SSL_CTX* to update | |
455 | cbinfo various parts of session state | |
456 | ||
457 | Returns: OK/DEFER/FAIL | |
458 | */ | |
459 | ||
460 | static int | |
3f7eeb86 | 461 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
462 | { |
463 | uschar *expanded; | |
464 | ||
465 | if (cbinfo->certificate == NULL) | |
466 | return OK; | |
467 | ||
468 | if (Ustrstr(cbinfo->certificate, US"tls_sni")) | |
469 | reexpand_tls_files_for_sni = TRUE; | |
470 | ||
471 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
472 | return DEFER; | |
473 | ||
474 | if (expanded != NULL) | |
475 | { | |
476 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
477 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
478 | return tls_error(string_sprintf( | |
479 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
480 | cbinfo->host, NULL); | |
481 | } | |
482 | ||
483 | if (cbinfo->privatekey != NULL && | |
484 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
485 | return DEFER; | |
486 | ||
487 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
488 | of the expansion is an empty string, ignore it also, and assume the private | |
489 | key is in the same file as the certificate. */ | |
490 | ||
491 | if (expanded != NULL && *expanded != 0) | |
492 | { | |
493 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
494 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
495 | return tls_error(string_sprintf( | |
496 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
497 | } | |
498 | ||
3f7eeb86 PP |
499 | #ifdef EXPERIMENTAL_OCSP |
500 | if (cbinfo->ocsp_file != NULL) | |
501 | { | |
502 | if (!expand_check(cbinfo->ocsp_file, US"tls_ocsp_file", &expanded)) | |
503 | return DEFER; | |
504 | ||
505 | if (expanded != NULL && *expanded != 0) | |
506 | { | |
507 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
508 | if (cbinfo->ocsp_file_expanded && | |
509 | (Ustrcmp(expanded, cbinfo->ocsp_file_expanded) == 0)) | |
510 | { | |
511 | DEBUG(D_tls) | |
512 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
513 | } else { | |
514 | ocsp_load_response(sctx, cbinfo, expanded); | |
515 | } | |
516 | } | |
517 | } | |
518 | #endif | |
519 | ||
7be682ca PP |
520 | return OK; |
521 | } | |
522 | ||
523 | ||
524 | ||
525 | ||
526 | /************************************************* | |
527 | * Callback to handle SNI * | |
528 | *************************************************/ | |
529 | ||
530 | /* Called when acting as server during the TLS session setup if a Server Name | |
531 | Indication extension was sent by the client. | |
532 | ||
533 | API documentation is OpenSSL s_server.c implementation. | |
534 | ||
535 | Arguments: | |
536 | s SSL* of the current session | |
537 | ad unknown (part of OpenSSL API) (unused) | |
538 | arg Callback of "our" registered data | |
539 | ||
540 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
541 | */ | |
542 | ||
7be682ca PP |
543 | static int |
544 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
545 | { | |
546 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 547 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 548 | int rc; |
3f0945ff | 549 | int old_pool = store_pool; |
7be682ca PP |
550 | |
551 | if (!servername) | |
552 | return SSL_TLSEXT_ERR_OK; | |
553 | ||
3f0945ff | 554 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
555 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
556 | ||
557 | /* Make the extension value available for expansion */ | |
3f0945ff PP |
558 | store_pool = POOL_PERM; |
559 | tls_sni = string_copy(US servername); | |
560 | store_pool = old_pool; | |
7be682ca PP |
561 | |
562 | if (!reexpand_tls_files_for_sni) | |
563 | return SSL_TLSEXT_ERR_OK; | |
564 | ||
565 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
566 | not confident that memcpy wouldn't break some internal reference counting. | |
567 | Especially since there's a references struct member, which would be off. */ | |
568 | ||
569 | ctx_sni = SSL_CTX_new(SSLv23_server_method()); | |
570 | if (!ctx_sni) | |
571 | { | |
572 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
573 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
574 | return SSL_TLSEXT_ERR_NOACK; | |
575 | } | |
576 | ||
577 | /* Not sure how many of these are actually needed, since SSL object | |
578 | already exists. Might even need this selfsame callback, for reneg? */ | |
579 | ||
580 | SSL_CTX_set_info_callback(ctx_sni, SSL_CTX_get_info_callback(ctx)); | |
581 | SSL_CTX_set_mode(ctx_sni, SSL_CTX_get_mode(ctx)); | |
582 | SSL_CTX_set_options(ctx_sni, SSL_CTX_get_options(ctx)); | |
583 | SSL_CTX_set_timeout(ctx_sni, SSL_CTX_get_timeout(ctx)); | |
584 | SSL_CTX_set_tlsext_servername_callback(ctx_sni, tls_servername_cb); | |
585 | SSL_CTX_set_tlsext_servername_arg(ctx_sni, cbinfo); | |
586 | if (cbinfo->server_cipher_list) | |
587 | SSL_CTX_set_cipher_list(ctx_sni, CS cbinfo->server_cipher_list); | |
3f7eeb86 PP |
588 | #ifdef EXPERIMENTAL_OCSP |
589 | if (cbinfo->ocsp_file) | |
590 | { | |
591 | SSL_CTX_set_tlsext_status_cb(ctx_sni, tls_stapling_cb); | |
592 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
593 | } | |
594 | #endif | |
7be682ca | 595 | |
3f7eeb86 | 596 | rc = setup_certs(ctx_sni, tls_verify_certificates, tls_crl, NULL, FALSE); |
7be682ca PP |
597 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
598 | ||
3f7eeb86 PP |
599 | /* do this after setup_certs, because this can require the certs for verifying |
600 | OCSP information. */ | |
601 | rc = tls_expand_session_files(ctx_sni, cbinfo); | |
7be682ca PP |
602 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
603 | ||
604 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); | |
605 | SSL_set_SSL_CTX(s, ctx_sni); | |
606 | ||
607 | return SSL_TLSEXT_ERR_OK; | |
608 | } | |
609 | ||
610 | ||
611 | ||
612 | ||
3f7eeb86 PP |
613 | #ifdef EXPERIMENTAL_OCSP |
614 | /************************************************* | |
615 | * Callback to handle OCSP Stapling * | |
616 | *************************************************/ | |
617 | ||
618 | /* Called when acting as server during the TLS session setup if the client | |
619 | requests OCSP information with a Certificate Status Request. | |
620 | ||
621 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
622 | project. | |
623 | ||
624 | */ | |
625 | ||
626 | static int | |
627 | tls_stapling_cb(SSL *s, void *arg) | |
628 | { | |
629 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
630 | uschar *response_der; | |
631 | int response_der_len; | |
632 | ||
633 | DEBUG(D_tls) debug_printf("Received TLS status request (OCSP stapling); %s response.\n", | |
634 | cbinfo->ocsp_response ? "have" : "lack"); | |
635 | if (!cbinfo->ocsp_response) | |
636 | return SSL_TLSEXT_ERR_NOACK; | |
637 | ||
638 | response_der = NULL; | |
639 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->ocsp_response, &response_der); | |
640 | if (response_der_len <= 0) | |
641 | return SSL_TLSEXT_ERR_NOACK; | |
642 | ||
643 | SSL_set_tlsext_status_ocsp_resp(ssl, response_der, response_der_len); | |
644 | return SSL_TLSEXT_ERR_OK; | |
645 | } | |
646 | ||
647 | #endif /* EXPERIMENTAL_OCSP */ | |
648 | ||
649 | ||
650 | ||
651 | ||
059ec3d9 PH |
652 | /************************************************* |
653 | * Initialize for TLS * | |
654 | *************************************************/ | |
655 | ||
656 | /* Called from both server and client code, to do preliminary initialization of | |
657 | the library. | |
658 | ||
659 | Arguments: | |
660 | host connected host, if client; NULL if server | |
661 | dhparam DH parameter file | |
662 | certificate certificate file | |
663 | privatekey private key | |
664 | addr address if client; NULL if server (for some randomness) | |
665 | ||
666 | Returns: OK/DEFER/FAIL | |
667 | */ | |
668 | ||
669 | static int | |
c91535f3 | 670 | tls_init(host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 PP |
671 | uschar *privatekey, |
672 | #ifdef EXPERIMENTAL_OCSP | |
673 | uschar *ocsp_file, | |
674 | #endif | |
675 | address_item *addr) | |
059ec3d9 | 676 | { |
77bb000f | 677 | long init_options; |
7be682ca | 678 | int rc; |
77bb000f | 679 | BOOL okay; |
7be682ca PP |
680 | tls_ext_ctx_cb *cbinfo; |
681 | ||
682 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
683 | cbinfo->certificate = certificate; | |
684 | cbinfo->privatekey = privatekey; | |
3f7eeb86 PP |
685 | #ifdef EXPERIMENTAL_OCSP |
686 | cbinfo->ocsp_file = ocsp_file; | |
687 | #endif | |
7be682ca PP |
688 | cbinfo->dhparam = dhparam; |
689 | cbinfo->host = host; | |
77bb000f | 690 | |
059ec3d9 PH |
691 | SSL_load_error_strings(); /* basic set up */ |
692 | OpenSSL_add_ssl_algorithms(); | |
693 | ||
388d6564 | 694 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 695 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
696 | list of available digests. */ |
697 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 698 | #endif |
a0475b69 | 699 | |
059ec3d9 PH |
700 | /* Create a context */ |
701 | ||
702 | ctx = SSL_CTX_new((host == NULL)? | |
703 | SSLv23_server_method() : SSLv23_client_method()); | |
704 | ||
7199e1ee | 705 | if (ctx == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
706 | |
707 | /* It turns out that we need to seed the random number generator this early in | |
708 | order to get the full complement of ciphers to work. It took me roughly a day | |
709 | of work to discover this by experiment. | |
710 | ||
711 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
712 | there. Otherwise, we have to make something up as best we can. Double check | |
713 | afterwards. */ | |
714 | ||
715 | if (!RAND_status()) | |
716 | { | |
717 | randstuff r; | |
9e3331ea | 718 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
719 | r.p = getpid(); |
720 | ||
721 | RAND_seed((uschar *)(&r), sizeof(r)); | |
722 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
723 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
724 | ||
725 | if (!RAND_status()) | |
7199e1ee | 726 | return tls_error(US"RAND_status", host, |
5ca6d115 | 727 | US"unable to seed random number generator"); |
059ec3d9 PH |
728 | } |
729 | ||
730 | /* Set up the information callback, which outputs if debugging is at a suitable | |
731 | level. */ | |
732 | ||
58c01c94 | 733 | SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); |
059ec3d9 | 734 | |
c80c5570 PP |
735 | /* Automatically re-try reads/writes after renegotiation. */ |
736 | (void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY); | |
737 | ||
77bb000f PP |
738 | /* Apply administrator-supplied work-arounds. |
739 | Historically we applied just one requested option, | |
740 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
741 | moved to an administrator-controlled list of options to specify and | |
742 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 743 | |
77bb000f PP |
744 | No OpenSSL version number checks: the options we accept depend upon the |
745 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 746 | |
77bb000f PP |
747 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
748 | if (!okay) | |
73a46702 | 749 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
750 | |
751 | if (init_options) | |
752 | { | |
753 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
754 | if (!(SSL_CTX_set_options(ctx, init_options))) | |
755 | return tls_error(string_sprintf( | |
756 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
757 | } | |
758 | else | |
759 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
760 | |
761 | /* Initialize with DH parameters if supplied */ | |
762 | ||
7199e1ee | 763 | if (!init_dh(dhparam, host)) return DEFER; |
059ec3d9 | 764 | |
3f7eeb86 | 765 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 766 | |
7be682ca PP |
767 | rc = tls_expand_session_files(ctx, cbinfo); |
768 | if (rc != OK) return rc; | |
c91535f3 | 769 | |
7be682ca PP |
770 | /* If we need to handle SNI, do so */ |
771 | #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) | |
3f0945ff PP |
772 | if (host == NULL) |
773 | { | |
3f7eeb86 PP |
774 | #ifdef EXPERIMENTAL_OCSP |
775 | /* We check ocsp_file, not ocsp_response, because we care about if | |
776 | the option exists, not what the current expansion might be, as SNI might | |
777 | change the certificate and OCSP file in use between now and the time the | |
778 | callback is invoked. */ | |
779 | if (cbinfo->ocsp_file) | |
780 | { | |
781 | SSL_CTX_set_tlsext_status_cb(ctx, tls_stapling_cb); | |
782 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
783 | } | |
784 | #endif | |
3f0945ff PP |
785 | /* We always do this, so that $tls_sni is available even if not used in |
786 | tls_certificate */ | |
787 | SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); | |
788 | SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo); | |
789 | } | |
7be682ca | 790 | #endif |
059ec3d9 PH |
791 | |
792 | /* Set up the RSA callback */ | |
793 | ||
794 | SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); | |
795 | ||
796 | /* Finally, set the timeout, and we are done */ | |
797 | ||
798 | SSL_CTX_set_timeout(ctx, ssl_session_timeout); | |
799 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); | |
7be682ca PP |
800 | |
801 | static_cbinfo = cbinfo; | |
802 | ||
059ec3d9 PH |
803 | return OK; |
804 | } | |
805 | ||
806 | ||
807 | ||
808 | ||
809 | /************************************************* | |
810 | * Get name of cipher in use * | |
811 | *************************************************/ | |
812 | ||
813 | /* The answer is left in a static buffer, and tls_cipher is set to point | |
814 | to it. | |
815 | ||
816 | Argument: pointer to an SSL structure for the connection | |
817 | Returns: nothing | |
818 | */ | |
819 | ||
820 | static void | |
821 | construct_cipher_name(SSL *ssl) | |
822 | { | |
823 | static uschar cipherbuf[256]; | |
57b3a7f5 PP |
824 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
825 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
826 | the accessor functions use const in the prototype. */ | |
827 | const SSL_CIPHER *c; | |
059ec3d9 | 828 | uschar *ver; |
059ec3d9 PH |
829 | |
830 | switch (ssl->session->ssl_version) | |
831 | { | |
832 | case SSL2_VERSION: | |
833 | ver = US"SSLv2"; | |
834 | break; | |
835 | ||
836 | case SSL3_VERSION: | |
837 | ver = US"SSLv3"; | |
838 | break; | |
839 | ||
840 | case TLS1_VERSION: | |
841 | ver = US"TLSv1"; | |
842 | break; | |
843 | ||
c80c5570 PP |
844 | #ifdef TLS1_1_VERSION |
845 | case TLS1_1_VERSION: | |
846 | ver = US"TLSv1.1"; | |
847 | break; | |
848 | #endif | |
849 | ||
850 | #ifdef TLS1_2_VERSION | |
851 | case TLS1_2_VERSION: | |
852 | ver = US"TLSv1.2"; | |
853 | break; | |
854 | #endif | |
855 | ||
059ec3d9 PH |
856 | default: |
857 | ver = US"UNKNOWN"; | |
858 | } | |
859 | ||
57b3a7f5 | 860 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
edc33b5f | 861 | SSL_CIPHER_get_bits(c, &tls_bits); |
059ec3d9 PH |
862 | |
863 | string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver, | |
edc33b5f | 864 | SSL_CIPHER_get_name(c), tls_bits); |
059ec3d9 PH |
865 | tls_cipher = cipherbuf; |
866 | ||
867 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
868 | } | |
869 | ||
870 | ||
871 | ||
872 | ||
873 | ||
874 | /************************************************* | |
875 | * Set up for verifying certificates * | |
876 | *************************************************/ | |
877 | ||
878 | /* Called by both client and server startup | |
879 | ||
880 | Arguments: | |
7be682ca | 881 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
882 | certs certs file or NULL |
883 | crl CRL file or NULL | |
884 | host NULL in a server; the remote host in a client | |
885 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
886 | otherwise passed as FALSE | |
887 | ||
888 | Returns: OK/DEFER/FAIL | |
889 | */ | |
890 | ||
891 | static int | |
7be682ca | 892 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional) |
059ec3d9 PH |
893 | { |
894 | uschar *expcerts, *expcrl; | |
895 | ||
896 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
897 | return DEFER; | |
898 | ||
899 | if (expcerts != NULL) | |
900 | { | |
901 | struct stat statbuf; | |
7be682ca | 902 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
7199e1ee | 903 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
904 | |
905 | if (Ustat(expcerts, &statbuf) < 0) | |
906 | { | |
907 | log_write(0, LOG_MAIN|LOG_PANIC, | |
908 | "failed to stat %s for certificates", expcerts); | |
909 | return DEFER; | |
910 | } | |
911 | else | |
912 | { | |
913 | uschar *file, *dir; | |
914 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
915 | { file = NULL; dir = expcerts; } | |
916 | else | |
917 | { file = expcerts; dir = NULL; } | |
918 | ||
919 | /* If a certificate file is empty, the next function fails with an | |
920 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
921 | certificates are recognized, but the error message is still misleading (it | |
922 | says no certificate was supplied.) But this is better. */ | |
923 | ||
924 | if ((file == NULL || statbuf.st_size > 0) && | |
7be682ca | 925 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) |
7199e1ee | 926 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 PH |
927 | |
928 | if (file != NULL) | |
929 | { | |
7be682ca | 930 | SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); |
059ec3d9 PH |
931 | } |
932 | } | |
933 | ||
934 | /* Handle a certificate revocation list. */ | |
935 | ||
936 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
937 | ||
8b417f2c PH |
938 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
939 | * merely reformatted it into the Exim code style.) | |
940 | ||
941 | * "From here I changed the code to add support for multiple crl's | |
942 | * in pem format in one file or to support hashed directory entries in | |
943 | * pem format instead of a file. This method now uses the library function | |
944 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
945 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
946 | * itself in the verify callback." */ | |
947 | ||
059ec3d9 PH |
948 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
949 | if (expcrl != NULL && *expcrl != 0) | |
950 | { | |
8b417f2c PH |
951 | struct stat statbufcrl; |
952 | if (Ustat(expcrl, &statbufcrl) < 0) | |
953 | { | |
954 | log_write(0, LOG_MAIN|LOG_PANIC, | |
955 | "failed to stat %s for certificates revocation lists", expcrl); | |
956 | return DEFER; | |
957 | } | |
958 | else | |
059ec3d9 | 959 | { |
8b417f2c PH |
960 | /* is it a file or directory? */ |
961 | uschar *file, *dir; | |
7be682ca | 962 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 963 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 964 | { |
8b417f2c PH |
965 | file = NULL; |
966 | dir = expcrl; | |
967 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
968 | } |
969 | else | |
970 | { | |
8b417f2c PH |
971 | file = expcrl; |
972 | dir = NULL; | |
973 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 974 | } |
8b417f2c | 975 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 976 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
977 | |
978 | /* setting the flags to check against the complete crl chain */ | |
979 | ||
980 | X509_STORE_set_flags(cvstore, | |
981 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 982 | } |
059ec3d9 PH |
983 | } |
984 | ||
985 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
986 | ||
987 | /* If verification is optional, don't fail if no certificate */ | |
988 | ||
7be682ca | 989 | SSL_CTX_set_verify(sctx, |
059ec3d9 PH |
990 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
991 | verify_callback); | |
992 | } | |
993 | ||
994 | return OK; | |
995 | } | |
996 | ||
997 | ||
998 | ||
999 | /************************************************* | |
1000 | * Start a TLS session in a server * | |
1001 | *************************************************/ | |
1002 | ||
1003 | /* This is called when Exim is running as a server, after having received | |
1004 | the STARTTLS command. It must respond to that command, and then negotiate | |
1005 | a TLS session. | |
1006 | ||
1007 | Arguments: | |
1008 | require_ciphers allowed ciphers | |
1009 | ||
1010 | Returns: OK on success | |
1011 | DEFER for errors before the start of the negotiation | |
1012 | FAIL for errors during the negotation; the server can't | |
1013 | continue running. | |
1014 | */ | |
1015 | ||
1016 | int | |
17c76198 | 1017 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1018 | { |
1019 | int rc; | |
1020 | uschar *expciphers; | |
7be682ca | 1021 | tls_ext_ctx_cb *cbinfo; |
059ec3d9 PH |
1022 | |
1023 | /* Check for previous activation */ | |
1024 | ||
1025 | if (tls_active >= 0) | |
1026 | { | |
5ca6d115 | 1027 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1028 | smtp_printf("554 Already in TLS\r\n"); |
1029 | return FAIL; | |
1030 | } | |
1031 | ||
1032 | /* Initialize the SSL library. If it fails, it will already have logged | |
1033 | the error. */ | |
1034 | ||
3f7eeb86 PP |
1035 | rc = tls_init(NULL, tls_dhparam, tls_certificate, tls_privatekey, |
1036 | #ifdef EXPERIMENTAL_OCSP | |
1037 | tls_ocsp_file, | |
1038 | #endif | |
1039 | NULL); | |
059ec3d9 | 1040 | if (rc != OK) return rc; |
7be682ca | 1041 | cbinfo = static_cbinfo; |
059ec3d9 PH |
1042 | |
1043 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1044 | return FAIL; | |
1045 | ||
1046 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1047 | were historically separated by underscores. So that I can use either form in my |
1048 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1049 | */ | |
059ec3d9 PH |
1050 | |
1051 | if (expciphers != NULL) | |
1052 | { | |
1053 | uschar *s = expciphers; | |
1054 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1055 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
1056 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
7199e1ee | 1057 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1058 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1059 | } |
1060 | ||
1061 | /* If this is a host for which certificate verification is mandatory or | |
1062 | optional, set up appropriately. */ | |
1063 | ||
1064 | tls_certificate_verified = FALSE; | |
1065 | verify_callback_called = FALSE; | |
1066 | ||
1067 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1068 | { | |
7be682ca | 1069 | rc = setup_certs(ctx, tls_verify_certificates, tls_crl, NULL, FALSE); |
059ec3d9 PH |
1070 | if (rc != OK) return rc; |
1071 | verify_optional = FALSE; | |
1072 | } | |
1073 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1074 | { | |
7be682ca | 1075 | rc = setup_certs(ctx, tls_verify_certificates, tls_crl, NULL, TRUE); |
059ec3d9 PH |
1076 | if (rc != OK) return rc; |
1077 | verify_optional = TRUE; | |
1078 | } | |
1079 | ||
1080 | /* Prepare for new connection */ | |
1081 | ||
7199e1ee | 1082 | if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1083 | |
1084 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1085 | * | |
1086 | * With the SSL_clear(), we get strange interoperability bugs with | |
1087 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1088 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1089 | * | |
1090 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1091 | * session shutdown. In this case, we have a brand new object and there's no | |
1092 | * obvious reason to immediately clear it. I'm guessing that this was | |
1093 | * originally added because of incomplete initialisation which the clear fixed, | |
1094 | * in some historic release. | |
1095 | */ | |
059ec3d9 PH |
1096 | |
1097 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1098 | on connection, where outputting anything now upsets the clients and tends to | |
1099 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1100 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1101 | mode, the fflush() happens when smtp_getc() is called. */ | |
1102 | ||
1103 | SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx)); | |
1104 | if (!tls_on_connect) | |
1105 | { | |
1106 | smtp_printf("220 TLS go ahead\r\n"); | |
1107 | fflush(smtp_out); | |
1108 | } | |
1109 | ||
1110 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1111 | that the OpenSSL library doesn't. */ | |
1112 | ||
56f5d9bd PH |
1113 | SSL_set_wfd(ssl, fileno(smtp_out)); |
1114 | SSL_set_rfd(ssl, fileno(smtp_in)); | |
059ec3d9 PH |
1115 | SSL_set_accept_state(ssl); |
1116 | ||
1117 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1118 | ||
1119 | sigalrm_seen = FALSE; | |
1120 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1121 | rc = SSL_accept(ssl); | |
1122 | alarm(0); | |
1123 | ||
1124 | if (rc <= 0) | |
1125 | { | |
7199e1ee | 1126 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1127 | if (ERR_get_error() == 0) |
1128 | log_write(0, LOG_MAIN, | |
a053d125 | 1129 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1130 | return FAIL; |
1131 | } | |
1132 | ||
1133 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1134 | ||
1135 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1136 | and initialize things. */ | |
1137 | ||
1138 | construct_cipher_name(ssl); | |
1139 | ||
1140 | DEBUG(D_tls) | |
1141 | { | |
1142 | uschar buf[2048]; | |
1143 | if (SSL_get_shared_ciphers(ssl, CS buf, sizeof(buf)) != NULL) | |
1144 | debug_printf("Shared ciphers: %s\n", buf); | |
1145 | } | |
1146 | ||
1147 | ||
1148 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); | |
1149 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1150 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1151 | ||
1152 | receive_getc = tls_getc; | |
1153 | receive_ungetc = tls_ungetc; | |
1154 | receive_feof = tls_feof; | |
1155 | receive_ferror = tls_ferror; | |
58eb016e | 1156 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 PH |
1157 | |
1158 | tls_active = fileno(smtp_out); | |
1159 | return OK; | |
1160 | } | |
1161 | ||
1162 | ||
1163 | ||
1164 | ||
1165 | ||
1166 | /************************************************* | |
1167 | * Start a TLS session in a client * | |
1168 | *************************************************/ | |
1169 | ||
1170 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1171 | ||
1172 | Argument: | |
1173 | fd the fd of the connection | |
1174 | host connected host (for messages) | |
83da1223 | 1175 | addr the first address |
059ec3d9 PH |
1176 | dhparam DH parameter file |
1177 | certificate certificate file | |
1178 | privatekey private key file | |
3f0945ff | 1179 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1180 | verify_certs file for certificate verify |
1181 | crl file containing CRL | |
1182 | require_ciphers list of allowed ciphers | |
83da1223 | 1183 | timeout startup timeout |
059ec3d9 PH |
1184 | |
1185 | Returns: OK on success | |
1186 | FAIL otherwise - note that tls_error() will not give DEFER | |
1187 | because this is not a server | |
1188 | */ | |
1189 | ||
1190 | int | |
1191 | tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, | |
3f0945ff PP |
1192 | uschar *certificate, uschar *privatekey, uschar *sni, |
1193 | uschar *verify_certs, uschar *crl, | |
17c76198 | 1194 | uschar *require_ciphers, int timeout) |
059ec3d9 PH |
1195 | { |
1196 | static uschar txt[256]; | |
1197 | uschar *expciphers; | |
1198 | X509* server_cert; | |
1199 | int rc; | |
1200 | ||
3f7eeb86 PP |
1201 | rc = tls_init(host, dhparam, certificate, privatekey, |
1202 | #ifdef EXPERIMENTAL_OCSP | |
1203 | NULL, | |
1204 | #endif | |
1205 | addr); | |
059ec3d9 PH |
1206 | if (rc != OK) return rc; |
1207 | ||
1208 | tls_certificate_verified = FALSE; | |
1209 | verify_callback_called = FALSE; | |
1210 | ||
1211 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1212 | return FAIL; | |
1213 | ||
1214 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1215 | are separated by underscores. So that I can use either form in my tests, and | |
1216 | also for general convenience, we turn underscores into hyphens here. */ | |
1217 | ||
1218 | if (expciphers != NULL) | |
1219 | { | |
1220 | uschar *s = expciphers; | |
1221 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1222 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
1223 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
7199e1ee | 1224 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1225 | } |
1226 | ||
7be682ca | 1227 | rc = setup_certs(ctx, verify_certs, crl, host, FALSE); |
059ec3d9 PH |
1228 | if (rc != OK) return rc; |
1229 | ||
7199e1ee | 1230 | if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", host, NULL); |
059ec3d9 PH |
1231 | SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx)); |
1232 | SSL_set_fd(ssl, fd); | |
1233 | SSL_set_connect_state(ssl); | |
1234 | ||
3f0945ff PP |
1235 | if (sni) |
1236 | { | |
1237 | if (!expand_check(sni, US"tls_sni", &tls_sni)) | |
1238 | return FAIL; | |
1239 | if (!Ustrlen(tls_sni)) | |
1240 | tls_sni = NULL; | |
1241 | else | |
1242 | { | |
1243 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_sni); | |
1244 | SSL_set_tlsext_host_name(ssl, tls_sni); | |
1245 | } | |
1246 | } | |
1247 | ||
059ec3d9 PH |
1248 | /* There doesn't seem to be a built-in timeout on connection. */ |
1249 | ||
1250 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1251 | sigalrm_seen = FALSE; | |
1252 | alarm(timeout); | |
1253 | rc = SSL_connect(ssl); | |
1254 | alarm(0); | |
1255 | ||
1256 | if (rc <= 0) | |
7199e1ee | 1257 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1258 | |
1259 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1260 | ||
453a6645 | 1261 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
059ec3d9 | 1262 | server_cert = SSL_get_peer_certificate (ssl); |
453a6645 PP |
1263 | if (server_cert) |
1264 | { | |
1265 | tls_peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), | |
1266 | CS txt, sizeof(txt)); | |
1267 | tls_peerdn = txt; | |
1268 | } | |
1269 | else | |
1270 | tls_peerdn = NULL; | |
059ec3d9 PH |
1271 | |
1272 | construct_cipher_name(ssl); /* Sets tls_cipher */ | |
1273 | ||
1274 | tls_active = fd; | |
1275 | return OK; | |
1276 | } | |
1277 | ||
1278 | ||
1279 | ||
1280 | ||
1281 | ||
1282 | /************************************************* | |
1283 | * TLS version of getc * | |
1284 | *************************************************/ | |
1285 | ||
1286 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1287 | it refills the buffer via the SSL reading function. | |
1288 | ||
1289 | Arguments: none | |
1290 | Returns: the next character or EOF | |
1291 | */ | |
1292 | ||
1293 | int | |
1294 | tls_getc(void) | |
1295 | { | |
1296 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1297 | { | |
1298 | int error; | |
1299 | int inbytes; | |
1300 | ||
c80c5570 PP |
1301 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
1302 | ssl_xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
1303 | |
1304 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1305 | inbytes = SSL_read(ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); | |
1306 | error = SSL_get_error(ssl, inbytes); | |
1307 | alarm(0); | |
1308 | ||
1309 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
1310 | closed down, not that the socket itself has been closed down. Revert to | |
1311 | non-SSL handling. */ | |
1312 | ||
1313 | if (error == SSL_ERROR_ZERO_RETURN) | |
1314 | { | |
1315 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1316 | ||
1317 | receive_getc = smtp_getc; | |
1318 | receive_ungetc = smtp_ungetc; | |
1319 | receive_feof = smtp_feof; | |
1320 | receive_ferror = smtp_ferror; | |
58eb016e | 1321 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 PH |
1322 | |
1323 | SSL_free(ssl); | |
1324 | ssl = NULL; | |
1325 | tls_active = -1; | |
3f0945ff | 1326 | tls_bits = 0; |
059ec3d9 PH |
1327 | tls_cipher = NULL; |
1328 | tls_peerdn = NULL; | |
3f0945ff | 1329 | tls_sni = NULL; |
059ec3d9 PH |
1330 | |
1331 | return smtp_getc(); | |
1332 | } | |
1333 | ||
1334 | /* Handle genuine errors */ | |
1335 | ||
ba084640 PP |
1336 | else if (error == SSL_ERROR_SSL) |
1337 | { | |
1338 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 1339 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
1340 | ssl_xfer_error = 1; |
1341 | return EOF; | |
1342 | } | |
1343 | ||
059ec3d9 PH |
1344 | else if (error != SSL_ERROR_NONE) |
1345 | { | |
1346 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
1347 | ssl_xfer_error = 1; | |
1348 | return EOF; | |
1349 | } | |
c80c5570 | 1350 | |
80a47a2c TK |
1351 | #ifndef DISABLE_DKIM |
1352 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
1353 | #endif | |
059ec3d9 PH |
1354 | ssl_xfer_buffer_hwm = inbytes; |
1355 | ssl_xfer_buffer_lwm = 0; | |
1356 | } | |
1357 | ||
1358 | /* Something in the buffer; return next uschar */ | |
1359 | ||
1360 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1361 | } | |
1362 | ||
1363 | ||
1364 | ||
1365 | /************************************************* | |
1366 | * Read bytes from TLS channel * | |
1367 | *************************************************/ | |
1368 | ||
1369 | /* | |
1370 | Arguments: | |
1371 | buff buffer of data | |
1372 | len size of buffer | |
1373 | ||
1374 | Returns: the number of bytes read | |
1375 | -1 after a failed read | |
1376 | */ | |
1377 | ||
1378 | int | |
1379 | tls_read(uschar *buff, size_t len) | |
1380 | { | |
1381 | int inbytes; | |
1382 | int error; | |
1383 | ||
c80c5570 PP |
1384 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
1385 | buff, (unsigned int)len); | |
059ec3d9 PH |
1386 | |
1387 | inbytes = SSL_read(ssl, CS buff, len); | |
1388 | error = SSL_get_error(ssl, inbytes); | |
1389 | ||
1390 | if (error == SSL_ERROR_ZERO_RETURN) | |
1391 | { | |
1392 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1393 | return -1; | |
1394 | } | |
1395 | else if (error != SSL_ERROR_NONE) | |
1396 | { | |
1397 | return -1; | |
1398 | } | |
1399 | ||
1400 | return inbytes; | |
1401 | } | |
1402 | ||
1403 | ||
1404 | ||
1405 | ||
1406 | ||
1407 | /************************************************* | |
1408 | * Write bytes down TLS channel * | |
1409 | *************************************************/ | |
1410 | ||
1411 | /* | |
1412 | Arguments: | |
1413 | buff buffer of data | |
1414 | len number of bytes | |
1415 | ||
1416 | Returns: the number of bytes after a successful write, | |
1417 | -1 after a failed write | |
1418 | */ | |
1419 | ||
1420 | int | |
1421 | tls_write(const uschar *buff, size_t len) | |
1422 | { | |
1423 | int outbytes; | |
1424 | int error; | |
1425 | int left = len; | |
1426 | ||
c80c5570 | 1427 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
1428 | while (left > 0) |
1429 | { | |
c80c5570 | 1430 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
1431 | outbytes = SSL_write(ssl, CS buff, left); |
1432 | error = SSL_get_error(ssl, outbytes); | |
1433 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1434 | switch (error) | |
1435 | { | |
1436 | case SSL_ERROR_SSL: | |
1437 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1438 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1439 | return -1; | |
1440 | ||
1441 | case SSL_ERROR_NONE: | |
1442 | left -= outbytes; | |
1443 | buff += outbytes; | |
1444 | break; | |
1445 | ||
1446 | case SSL_ERROR_ZERO_RETURN: | |
1447 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1448 | return -1; | |
1449 | ||
1450 | default: | |
1451 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1452 | return -1; | |
1453 | } | |
1454 | } | |
1455 | return len; | |
1456 | } | |
1457 | ||
1458 | ||
1459 | ||
1460 | /************************************************* | |
1461 | * Close down a TLS session * | |
1462 | *************************************************/ | |
1463 | ||
1464 | /* This is also called from within a delivery subprocess forked from the | |
1465 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1466 | would tamper with the SSL session in the parent process). | |
1467 | ||
1468 | Arguments: TRUE if SSL_shutdown is to be called | |
1469 | Returns: nothing | |
1470 | */ | |
1471 | ||
1472 | void | |
1473 | tls_close(BOOL shutdown) | |
1474 | { | |
1475 | if (tls_active < 0) return; /* TLS was not active */ | |
1476 | ||
1477 | if (shutdown) | |
1478 | { | |
1479 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
1480 | SSL_shutdown(ssl); | |
1481 | } | |
1482 | ||
1483 | SSL_free(ssl); | |
1484 | ssl = NULL; | |
1485 | ||
1486 | tls_active = -1; | |
1487 | } | |
1488 | ||
36f12725 NM |
1489 | |
1490 | ||
1491 | ||
1492 | /************************************************* | |
1493 | * Report the library versions. * | |
1494 | *************************************************/ | |
1495 | ||
1496 | /* There have historically been some issues with binary compatibility in | |
1497 | OpenSSL libraries; if Exim (like many other applications) is built against | |
1498 | one version of OpenSSL but the run-time linker picks up another version, | |
1499 | it can result in serious failures, including crashing with a SIGSEGV. So | |
1500 | report the version found by the compiler and the run-time version. | |
1501 | ||
1502 | Arguments: a FILE* to print the results to | |
1503 | Returns: nothing | |
1504 | */ | |
1505 | ||
1506 | void | |
1507 | tls_version_report(FILE *f) | |
1508 | { | |
754a0503 PP |
1509 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
1510 | " Runtime: %s\n", | |
1511 | OPENSSL_VERSION_TEXT, | |
1512 | SSLeay_version(SSLEAY_VERSION)); | |
36f12725 NM |
1513 | } |
1514 | ||
9e3331ea TK |
1515 | |
1516 | ||
1517 | ||
1518 | /************************************************* | |
17c76198 | 1519 | * Random number generation * |
9e3331ea TK |
1520 | *************************************************/ |
1521 | ||
1522 | /* Pseudo-random number generation. The result is not expected to be | |
1523 | cryptographically strong but not so weak that someone will shoot themselves | |
1524 | in the foot using it as a nonce in input in some email header scheme or | |
1525 | whatever weirdness they'll twist this into. The result should handle fork() | |
1526 | and avoid repeating sequences. OpenSSL handles that for us. | |
1527 | ||
1528 | Arguments: | |
1529 | max range maximum | |
1530 | Returns a random number in range [0, max-1] | |
1531 | */ | |
1532 | ||
1533 | int | |
17c76198 | 1534 | vaguely_random_number(int max) |
9e3331ea TK |
1535 | { |
1536 | unsigned int r; | |
1537 | int i, needed_len; | |
1538 | uschar *p; | |
1539 | uschar smallbuf[sizeof(r)]; | |
1540 | ||
1541 | if (max <= 1) | |
1542 | return 0; | |
1543 | ||
1544 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ | |
1545 | if (!RAND_status()) | |
1546 | { | |
1547 | randstuff r; | |
1548 | gettimeofday(&r.tv, NULL); | |
1549 | r.p = getpid(); | |
1550 | ||
1551 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1552 | } | |
1553 | /* We're after pseudo-random, not random; if we still don't have enough data | |
1554 | in the internal PRNG then our options are limited. We could sleep and hope | |
1555 | for entropy to come along (prayer technique) but if the system is so depleted | |
1556 | in the first place then something is likely to just keep taking it. Instead, | |
1557 | we'll just take whatever little bit of pseudo-random we can still manage to | |
1558 | get. */ | |
1559 | ||
1560 | needed_len = sizeof(r); | |
1561 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1562 | asked for a number less than 10. */ | |
1563 | for (r = max, i = 0; r; ++i) | |
1564 | r >>= 1; | |
1565 | i = (i + 7) / 8; | |
1566 | if (i < needed_len) | |
1567 | needed_len = i; | |
1568 | ||
1569 | /* We do not care if crypto-strong */ | |
17c76198 PP |
1570 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
1571 | if (i < 0) | |
1572 | { | |
1573 | DEBUG(D_all) | |
1574 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
1575 | return vaguely_random_number_fallback(max); | |
1576 | } | |
1577 | ||
9e3331ea TK |
1578 | r = 0; |
1579 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
1580 | { | |
1581 | r *= 256; | |
1582 | r += *p; | |
1583 | } | |
1584 | ||
1585 | /* We don't particularly care about weighted results; if someone wants | |
1586 | smooth distribution and cares enough then they should submit a patch then. */ | |
1587 | return r % max; | |
1588 | } | |
1589 | ||
77bb000f PP |
1590 | |
1591 | ||
1592 | ||
1593 | /************************************************* | |
1594 | * OpenSSL option parse * | |
1595 | *************************************************/ | |
1596 | ||
1597 | /* Parse one option for tls_openssl_options_parse below | |
1598 | ||
1599 | Arguments: | |
1600 | name one option name | |
1601 | value place to store a value for it | |
1602 | Returns success or failure in parsing | |
1603 | */ | |
1604 | ||
1605 | struct exim_openssl_option { | |
1606 | uschar *name; | |
1607 | long value; | |
1608 | }; | |
1609 | /* We could use a macro to expand, but we need the ifdef and not all the | |
1610 | options document which version they were introduced in. Policylet: include | |
1611 | all options unless explicitly for DTLS, let the administrator choose which | |
1612 | to apply. | |
1613 | ||
1614 | This list is current as of: | |
c80c5570 | 1615 | ==> 1.0.1b <== */ |
77bb000f PP |
1616 | static struct exim_openssl_option exim_openssl_options[] = { |
1617 | /* KEEP SORTED ALPHABETICALLY! */ | |
1618 | #ifdef SSL_OP_ALL | |
73a46702 | 1619 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
1620 | #endif |
1621 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 1622 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
1623 | #endif |
1624 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 1625 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
1626 | #endif |
1627 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 1628 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
1629 | #endif |
1630 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 1631 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
1632 | #endif |
1633 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 1634 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
1635 | #endif |
1636 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 1637 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
1638 | #endif |
1639 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 1640 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
1641 | #endif |
1642 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 1643 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
1644 | #endif |
1645 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 1646 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
1647 | #endif |
1648 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 1649 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 1650 | #endif |
c80c5570 PP |
1651 | #ifdef SSL_OP_NO_COMPRESSION |
1652 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
1653 | #endif | |
77bb000f | 1654 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 1655 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 1656 | #endif |
c0c7b2da PP |
1657 | #ifdef SSL_OP_NO_SSLv2 |
1658 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
1659 | #endif | |
1660 | #ifdef SSL_OP_NO_SSLv3 | |
1661 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
1662 | #endif | |
1663 | #ifdef SSL_OP_NO_TICKET | |
1664 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
1665 | #endif | |
1666 | #ifdef SSL_OP_NO_TLSv1 | |
1667 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
1668 | #endif | |
c80c5570 PP |
1669 | #ifdef SSL_OP_NO_TLSv1_1 |
1670 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
1671 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
1672 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
1673 | #else | |
1674 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
1675 | #endif | |
1676 | #endif | |
1677 | #ifdef SSL_OP_NO_TLSv1_2 | |
1678 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
1679 | #endif | |
77bb000f | 1680 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 1681 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
1682 | #endif |
1683 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 1684 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
1685 | #endif |
1686 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 1687 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
1688 | #endif |
1689 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 1690 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
1691 | #endif |
1692 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 1693 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
1694 | #endif |
1695 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 1696 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
1697 | #endif |
1698 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 1699 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
1700 | #endif |
1701 | }; | |
1702 | static int exim_openssl_options_size = | |
1703 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
1704 | ||
c80c5570 | 1705 | |
77bb000f PP |
1706 | static BOOL |
1707 | tls_openssl_one_option_parse(uschar *name, long *value) | |
1708 | { | |
1709 | int first = 0; | |
1710 | int last = exim_openssl_options_size; | |
1711 | while (last > first) | |
1712 | { | |
1713 | int middle = (first + last)/2; | |
1714 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
1715 | if (c == 0) | |
1716 | { | |
1717 | *value = exim_openssl_options[middle].value; | |
1718 | return TRUE; | |
1719 | } | |
1720 | else if (c > 0) | |
1721 | first = middle + 1; | |
1722 | else | |
1723 | last = middle; | |
1724 | } | |
1725 | return FALSE; | |
1726 | } | |
1727 | ||
1728 | ||
1729 | ||
1730 | ||
1731 | /************************************************* | |
1732 | * OpenSSL option parsing logic * | |
1733 | *************************************************/ | |
1734 | ||
1735 | /* OpenSSL has a number of compatibility options which an administrator might | |
1736 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
1737 | we look like log_selector. | |
1738 | ||
1739 | Arguments: | |
1740 | option_spec the administrator-supplied string of options | |
1741 | results ptr to long storage for the options bitmap | |
1742 | Returns success or failure | |
1743 | */ | |
1744 | ||
1745 | BOOL | |
1746 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
1747 | { | |
1748 | long result, item; | |
1749 | uschar *s, *end; | |
1750 | uschar keep_c; | |
1751 | BOOL adding, item_parsed; | |
1752 | ||
0e944a0d | 1753 | result = 0L; |
b1770b6e | 1754 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 1755 | * from default because it increases BEAST susceptibility. */ |
77bb000f PP |
1756 | |
1757 | if (option_spec == NULL) | |
1758 | { | |
1759 | *results = result; | |
1760 | return TRUE; | |
1761 | } | |
1762 | ||
1763 | for (s=option_spec; *s != '\0'; /**/) | |
1764 | { | |
1765 | while (isspace(*s)) ++s; | |
1766 | if (*s == '\0') | |
1767 | break; | |
1768 | if (*s != '+' && *s != '-') | |
1769 | { | |
1770 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 1771 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
1772 | return FALSE; |
1773 | } | |
1774 | adding = *s++ == '+'; | |
1775 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
1776 | keep_c = *end; | |
1777 | *end = '\0'; | |
1778 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
1779 | if (!item_parsed) | |
1780 | { | |
0e944a0d | 1781 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
1782 | return FALSE; |
1783 | } | |
1784 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
1785 | adding ? "adding" : "removing", result, item, s); | |
1786 | if (adding) | |
1787 | result |= item; | |
1788 | else | |
1789 | result &= ~item; | |
1790 | *end = keep_c; | |
1791 | s = end; | |
1792 | } | |
1793 | ||
1794 | *results = result; | |
1795 | return TRUE; | |
1796 | } | |
1797 | ||
059ec3d9 | 1798 | /* End of tls-openssl.c */ |