Commit | Line | Data |
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059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
c4ceed07 | 5 | /* Copyright (c) University of Cambridge 1995 - 2012 */ |
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 | 31 | |
3bcbbbe2 PP |
32 | #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) |
33 | #define EXIM_HAVE_OPENSSL_TLSEXT | |
34 | #endif | |
35 | ||
059ec3d9 PH |
36 | /* Structure for collecting random data for seeding. */ |
37 | ||
38 | typedef struct randstuff { | |
9e3331ea TK |
39 | struct timeval tv; |
40 | pid_t p; | |
059ec3d9 PH |
41 | } randstuff; |
42 | ||
43 | /* Local static variables */ | |
44 | ||
45 | static BOOL verify_callback_called = FALSE; | |
46 | static const uschar *sid_ctx = US"exim"; | |
47 | ||
817d9f57 JH |
48 | static SSL_CTX *client_ctx = NULL; |
49 | static SSL_CTX *server_ctx = NULL; | |
50 | static SSL *client_ssl = NULL; | |
51 | static SSL *server_ssl = NULL; | |
35731706 | 52 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
53 | static SSL_CTX *client_sni = NULL; |
54 | static SSL_CTX *server_sni = NULL; | |
35731706 | 55 | #endif |
059ec3d9 PH |
56 | |
57 | static char ssl_errstring[256]; | |
58 | ||
59 | static int ssl_session_timeout = 200; | |
60 | static BOOL verify_optional = FALSE; | |
61 | ||
7be682ca | 62 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
63 | |
64 | ||
7be682ca PP |
65 | typedef struct tls_ext_ctx_cb { |
66 | uschar *certificate; | |
67 | uschar *privatekey; | |
3f7eeb86 PP |
68 | #ifdef EXPERIMENTAL_OCSP |
69 | uschar *ocsp_file; | |
70 | uschar *ocsp_file_expanded; | |
71 | OCSP_RESPONSE *ocsp_response; | |
72 | #endif | |
7be682ca PP |
73 | uschar *dhparam; |
74 | /* these are cached from first expand */ | |
75 | uschar *server_cipher_list; | |
76 | /* only passed down to tls_error: */ | |
77 | host_item *host; | |
78 | } tls_ext_ctx_cb; | |
79 | ||
80 | /* should figure out a cleanup of API to handle state preserved per | |
81 | implementation, for various reasons, which can be void * in the APIs. | |
82 | For now, we hack around it. */ | |
817d9f57 JH |
83 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
84 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
85 | |
86 | static int | |
87 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional); | |
059ec3d9 | 88 | |
3f7eeb86 | 89 | /* Callbacks */ |
3bcbbbe2 | 90 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 91 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 92 | #endif |
3f7eeb86 PP |
93 | #ifdef EXPERIMENTAL_OCSP |
94 | static int tls_stapling_cb(SSL *s, void *arg); | |
95 | #endif | |
96 | ||
059ec3d9 PH |
97 | |
98 | /************************************************* | |
99 | * Handle TLS error * | |
100 | *************************************************/ | |
101 | ||
102 | /* Called from lots of places when errors occur before actually starting to do | |
103 | the TLS handshake, that is, while the session is still in clear. Always returns | |
104 | DEFER for a server and FAIL for a client so that most calls can use "return | |
105 | tls_error(...)" to do this processing and then give an appropriate return. A | |
106 | single function is used for both server and client, because it is called from | |
107 | some shared functions. | |
108 | ||
109 | Argument: | |
110 | prefix text to include in the logged error | |
111 | host NULL if setting up a server; | |
112 | the connected host if setting up a client | |
7199e1ee | 113 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
114 | |
115 | Returns: OK/DEFER/FAIL | |
116 | */ | |
117 | ||
118 | static int | |
7199e1ee | 119 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 120 | { |
7199e1ee TF |
121 | if (msg == NULL) |
122 | { | |
123 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 124 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
125 | } |
126 | ||
059ec3d9 PH |
127 | if (host == NULL) |
128 | { | |
7199e1ee | 129 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 130 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
131 | conn_info += 5; |
132 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
133 | conn_info, prefix, msg); | |
059ec3d9 PH |
134 | return DEFER; |
135 | } | |
136 | else | |
137 | { | |
138 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
7199e1ee | 139 | host->name, host->address, prefix, msg); |
059ec3d9 PH |
140 | return FAIL; |
141 | } | |
142 | } | |
143 | ||
144 | ||
145 | ||
146 | /************************************************* | |
147 | * Callback to generate RSA key * | |
148 | *************************************************/ | |
149 | ||
150 | /* | |
151 | Arguments: | |
152 | s SSL connection | |
153 | export not used | |
154 | keylength keylength | |
155 | ||
156 | Returns: pointer to generated key | |
157 | */ | |
158 | ||
159 | static RSA * | |
160 | rsa_callback(SSL *s, int export, int keylength) | |
161 | { | |
162 | RSA *rsa_key; | |
163 | export = export; /* Shut picky compilers up */ | |
164 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
165 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
166 | if (rsa_key == NULL) | |
167 | { | |
168 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
169 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
170 | ssl_errstring); | |
171 | return NULL; | |
172 | } | |
173 | return rsa_key; | |
174 | } | |
175 | ||
176 | ||
177 | ||
178 | ||
179 | /************************************************* | |
180 | * Callback for verification * | |
181 | *************************************************/ | |
182 | ||
183 | /* The SSL library does certificate verification if set up to do so. This | |
184 | callback has the current yes/no state is in "state". If verification succeeded, | |
185 | we set up the tls_peerdn string. If verification failed, what happens depends | |
186 | on whether the client is required to present a verifiable certificate or not. | |
187 | ||
188 | If verification is optional, we change the state to yes, but still log the | |
189 | verification error. For some reason (it really would help to have proper | |
190 | documentation of OpenSSL), this callback function then gets called again, this | |
191 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
192 | value, but we must take care not to set the private verified flag on the second | |
193 | time through. | |
194 | ||
195 | Note: this function is not called if the client fails to present a certificate | |
196 | when asked. We get here only if a certificate has been received. Handling of | |
197 | optional verification for this case is done when requesting SSL to verify, by | |
198 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
199 | ||
200 | Arguments: | |
201 | state current yes/no state as 1/0 | |
202 | x509ctx certificate information. | |
203 | ||
204 | Returns: 1 if verified, 0 if not | |
205 | */ | |
206 | ||
207 | static int | |
208 | verify_callback(int state, X509_STORE_CTX *x509ctx) | |
209 | { | |
210 | static uschar txt[256]; | |
211 | ||
212 | X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert), | |
213 | CS txt, sizeof(txt)); | |
214 | ||
215 | if (state == 0) | |
216 | { | |
217 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
218 | x509ctx->error_depth, | |
219 | X509_verify_cert_error_string(x509ctx->error), | |
220 | txt); | |
817d9f57 | 221 | tls_in.certificate_verified = FALSE; |
059ec3d9 PH |
222 | verify_callback_called = TRUE; |
223 | if (!verify_optional) return 0; /* reject */ | |
224 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " | |
225 | "tls_try_verify_hosts)\n"); | |
226 | return 1; /* accept */ | |
227 | } | |
228 | ||
229 | if (x509ctx->error_depth != 0) | |
230 | { | |
231 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n", | |
232 | x509ctx->error_depth, txt); | |
233 | } | |
234 | else | |
235 | { | |
236 | DEBUG(D_tls) debug_printf("SSL%s peer: %s\n", | |
237 | verify_callback_called? "" : " authenticated", txt); | |
817d9f57 | 238 | tls_in.peerdn = txt; |
059ec3d9 PH |
239 | } |
240 | ||
817d9f57 | 241 | if (!verify_callback_called) tls_in.certificate_verified = TRUE; |
059ec3d9 PH |
242 | verify_callback_called = TRUE; |
243 | ||
244 | return 1; /* accept */ | |
245 | } | |
246 | ||
247 | ||
248 | ||
249 | /************************************************* | |
250 | * Information callback * | |
251 | *************************************************/ | |
252 | ||
253 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
254 | are doing. We copy the string to the debugging output when TLS debugging has |
255 | been requested. | |
059ec3d9 PH |
256 | |
257 | Arguments: | |
258 | s the SSL connection | |
259 | where | |
260 | ret | |
261 | ||
262 | Returns: nothing | |
263 | */ | |
264 | ||
265 | static void | |
266 | info_callback(SSL *s, int where, int ret) | |
267 | { | |
268 | where = where; | |
269 | ret = ret; | |
270 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
271 | } | |
272 | ||
273 | ||
274 | ||
275 | /************************************************* | |
276 | * Initialize for DH * | |
277 | *************************************************/ | |
278 | ||
279 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
280 | ||
281 | Arguments: | |
a799883d | 282 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 283 | host connected host, if client; NULL if server |
059ec3d9 PH |
284 | |
285 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
286 | */ | |
287 | ||
288 | static BOOL | |
817d9f57 | 289 | <<<<<<< HEAD |
a799883d | 290 | init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host) |
817d9f57 JH |
291 | ======= |
292 | init_dh(SSL_CTX *ctx, uschar *dhparam, host_item *host) | |
293 | >>>>>>> Dual-tls - split management of TLS into in- and out-bound connection-handling. | |
059ec3d9 | 294 | { |
059ec3d9 PH |
295 | BIO *bio; |
296 | DH *dh; | |
297 | uschar *dhexpanded; | |
a799883d | 298 | const char *pem; |
059ec3d9 PH |
299 | |
300 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
301 | return FALSE; | |
302 | ||
a799883d | 303 | if (dhexpanded == NULL || *dhexpanded == '\0') |
059ec3d9 | 304 | { |
a799883d | 305 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
059ec3d9 | 306 | } |
a799883d | 307 | else if (dhexpanded[0] == '/') |
059ec3d9 | 308 | { |
a799883d PP |
309 | bio = BIO_new_file(CS dhexpanded, "r"); |
310 | if (bio == NULL) | |
059ec3d9 | 311 | { |
7199e1ee | 312 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
313 | host, US strerror(errno)); |
314 | return FALSE; | |
059ec3d9 | 315 | } |
a799883d PP |
316 | } |
317 | else | |
318 | { | |
319 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 320 | { |
a799883d PP |
321 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
322 | return TRUE; | |
059ec3d9 | 323 | } |
a799883d PP |
324 | |
325 | pem = std_dh_prime_named(dhexpanded); | |
326 | if (!pem) | |
327 | { | |
328 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
329 | host, US strerror(errno)); | |
330 | return FALSE; | |
331 | } | |
332 | bio = BIO_new_mem_buf(CS pem, -1); | |
333 | } | |
334 | ||
335 | dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL); | |
336 | if (dh == NULL) | |
337 | { | |
059ec3d9 | 338 | BIO_free(bio); |
a799883d PP |
339 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
340 | host, NULL); | |
341 | return FALSE; | |
342 | } | |
343 | ||
344 | /* Even if it is larger, we silently return success rather than cause things | |
345 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
346 | * debatable choice. */ | |
347 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
348 | { | |
349 | DEBUG(D_tls) | |
350 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
351 | 8*DH_size(dh), tls_dh_max_bits); | |
352 | } | |
353 | else | |
354 | { | |
355 | SSL_CTX_set_tmp_dh(sctx, dh); | |
356 | DEBUG(D_tls) | |
357 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
358 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
359 | } |
360 | ||
a799883d PP |
361 | DH_free(dh); |
362 | BIO_free(bio); | |
363 | ||
364 | return TRUE; | |
059ec3d9 PH |
365 | } |
366 | ||
367 | ||
368 | ||
369 | ||
3f7eeb86 PP |
370 | #ifdef EXPERIMENTAL_OCSP |
371 | /************************************************* | |
372 | * Load OCSP information into state * | |
373 | *************************************************/ | |
374 | ||
375 | /* Called to load the OCSP response from the given file into memory, once | |
376 | caller has determined this is needed. Checks validity. Debugs a message | |
377 | if invalid. | |
378 | ||
379 | ASSUMES: single response, for single cert. | |
380 | ||
381 | Arguments: | |
382 | sctx the SSL_CTX* to update | |
383 | cbinfo various parts of session state | |
384 | expanded the filename putatively holding an OCSP response | |
385 | ||
386 | */ | |
387 | ||
388 | static void | |
389 | ocsp_load_response(SSL_CTX *sctx, | |
390 | tls_ext_ctx_cb *cbinfo, | |
391 | const uschar *expanded) | |
392 | { | |
393 | BIO *bio; | |
394 | OCSP_RESPONSE *resp; | |
395 | OCSP_BASICRESP *basic_response; | |
396 | OCSP_SINGLERESP *single_response; | |
397 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
398 | X509_STORE *store; | |
399 | unsigned long verify_flags; | |
400 | int status, reason, i; | |
401 | ||
402 | cbinfo->ocsp_file_expanded = string_copy(expanded); | |
403 | if (cbinfo->ocsp_response) | |
404 | { | |
405 | OCSP_RESPONSE_free(cbinfo->ocsp_response); | |
406 | cbinfo->ocsp_response = NULL; | |
407 | } | |
408 | ||
409 | bio = BIO_new_file(CS cbinfo->ocsp_file_expanded, "rb"); | |
410 | if (!bio) | |
411 | { | |
412 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
413 | cbinfo->ocsp_file_expanded); | |
414 | return; | |
415 | } | |
416 | ||
417 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
418 | BIO_free(bio); | |
419 | if (!resp) | |
420 | { | |
421 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
422 | return; | |
423 | } | |
424 | ||
425 | status = OCSP_response_status(resp); | |
426 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
427 | { | |
428 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
429 | OCSP_response_status_str(status), status); | |
430 | return; | |
431 | } | |
432 | ||
433 | basic_response = OCSP_response_get1_basic(resp); | |
434 | if (!basic_response) | |
435 | { | |
436 | DEBUG(D_tls) | |
437 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
438 | return; | |
439 | } | |
440 | ||
441 | store = SSL_CTX_get_cert_store(sctx); | |
442 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
443 | ||
444 | /* May need to expose ability to adjust those flags? | |
445 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
446 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
447 | ||
448 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
449 | if (i <= 0) | |
450 | { | |
451 | DEBUG(D_tls) { | |
452 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
453 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
454 | } | |
455 | return; | |
456 | } | |
457 | ||
458 | /* Here's the simplifying assumption: there's only one response, for the | |
459 | one certificate we use, and nothing for anything else in a chain. If this | |
460 | proves false, we need to extract a cert id from our issued cert | |
461 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
462 | right cert in the stack and then calls OCSP_single_get0_status()). | |
463 | ||
464 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
465 | single_response = OCSP_resp_get0(basic_response, 0); | |
466 | if (!single_response) | |
467 | { | |
468 | DEBUG(D_tls) | |
469 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
470 | return; | |
471 | } | |
472 | ||
473 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
474 | /* how does this status differ from the one above? */ | |
475 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
476 | { | |
477 | DEBUG(D_tls) debug_printf("OCSP response not valid (take 2): %s (%d)\n", | |
478 | OCSP_response_status_str(status), status); | |
479 | return; | |
480 | } | |
481 | ||
482 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
483 | { | |
484 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
485 | return; | |
486 | } | |
487 | ||
488 | cbinfo->ocsp_response = resp; | |
489 | } | |
490 | #endif | |
491 | ||
492 | ||
493 | ||
494 | ||
7be682ca PP |
495 | /************************************************* |
496 | * Expand key and cert file specs * | |
497 | *************************************************/ | |
498 | ||
499 | /* Called once during tls_init and possibly againt during TLS setup, for a | |
500 | new context, if Server Name Indication was used and tls_sni was seen in | |
501 | the certificate string. | |
502 | ||
503 | Arguments: | |
504 | sctx the SSL_CTX* to update | |
505 | cbinfo various parts of session state | |
506 | ||
507 | Returns: OK/DEFER/FAIL | |
508 | */ | |
509 | ||
510 | static int | |
3f7eeb86 | 511 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
512 | { |
513 | uschar *expanded; | |
514 | ||
515 | if (cbinfo->certificate == NULL) | |
516 | return OK; | |
517 | ||
518 | if (Ustrstr(cbinfo->certificate, US"tls_sni")) | |
519 | reexpand_tls_files_for_sni = TRUE; | |
520 | ||
521 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
522 | return DEFER; | |
523 | ||
524 | if (expanded != NULL) | |
525 | { | |
526 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
527 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
528 | return tls_error(string_sprintf( | |
529 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
530 | cbinfo->host, NULL); | |
531 | } | |
532 | ||
533 | if (cbinfo->privatekey != NULL && | |
534 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
535 | return DEFER; | |
536 | ||
537 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
538 | of the expansion is an empty string, ignore it also, and assume the private | |
539 | key is in the same file as the certificate. */ | |
540 | ||
541 | if (expanded != NULL && *expanded != 0) | |
542 | { | |
543 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
544 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
545 | return tls_error(string_sprintf( | |
546 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
547 | } | |
548 | ||
3f7eeb86 PP |
549 | #ifdef EXPERIMENTAL_OCSP |
550 | if (cbinfo->ocsp_file != NULL) | |
551 | { | |
552 | if (!expand_check(cbinfo->ocsp_file, US"tls_ocsp_file", &expanded)) | |
553 | return DEFER; | |
554 | ||
555 | if (expanded != NULL && *expanded != 0) | |
556 | { | |
557 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
558 | if (cbinfo->ocsp_file_expanded && | |
559 | (Ustrcmp(expanded, cbinfo->ocsp_file_expanded) == 0)) | |
560 | { | |
561 | DEBUG(D_tls) | |
562 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
563 | } else { | |
564 | ocsp_load_response(sctx, cbinfo, expanded); | |
565 | } | |
566 | } | |
567 | } | |
568 | #endif | |
569 | ||
7be682ca PP |
570 | return OK; |
571 | } | |
572 | ||
573 | ||
574 | ||
575 | ||
576 | /************************************************* | |
577 | * Callback to handle SNI * | |
578 | *************************************************/ | |
579 | ||
580 | /* Called when acting as server during the TLS session setup if a Server Name | |
581 | Indication extension was sent by the client. | |
582 | ||
583 | API documentation is OpenSSL s_server.c implementation. | |
584 | ||
585 | Arguments: | |
586 | s SSL* of the current session | |
587 | ad unknown (part of OpenSSL API) (unused) | |
588 | arg Callback of "our" registered data | |
589 | ||
590 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
591 | */ | |
592 | ||
3bcbbbe2 | 593 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
594 | static int |
595 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
596 | { | |
597 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 598 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 599 | int rc; |
3f0945ff | 600 | int old_pool = store_pool; |
7be682ca PP |
601 | |
602 | if (!servername) | |
603 | return SSL_TLSEXT_ERR_OK; | |
604 | ||
3f0945ff | 605 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
606 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
607 | ||
608 | /* Make the extension value available for expansion */ | |
3f0945ff | 609 | store_pool = POOL_PERM; |
817d9f57 | 610 | tls_in.sni = string_copy(US servername); |
3f0945ff | 611 | store_pool = old_pool; |
7be682ca PP |
612 | |
613 | if (!reexpand_tls_files_for_sni) | |
614 | return SSL_TLSEXT_ERR_OK; | |
615 | ||
616 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
617 | not confident that memcpy wouldn't break some internal reference counting. | |
618 | Especially since there's a references struct member, which would be off. */ | |
619 | ||
817d9f57 JH |
620 | server_sni = SSL_CTX_new(SSLv23_server_method()); |
621 | if (!server_sni) | |
7be682ca PP |
622 | { |
623 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
624 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
625 | return SSL_TLSEXT_ERR_NOACK; | |
626 | } | |
627 | ||
628 | /* Not sure how many of these are actually needed, since SSL object | |
629 | already exists. Might even need this selfsame callback, for reneg? */ | |
630 | ||
817d9f57 JH |
631 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
632 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
633 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
634 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
635 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
636 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
7be682ca | 637 | if (cbinfo->server_cipher_list) |
817d9f57 | 638 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
3f7eeb86 PP |
639 | #ifdef EXPERIMENTAL_OCSP |
640 | if (cbinfo->ocsp_file) | |
641 | { | |
817d9f57 | 642 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_stapling_cb); |
3f7eeb86 PP |
643 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); |
644 | } | |
645 | #endif | |
7be682ca | 646 | |
817d9f57 | 647 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE); |
7be682ca PP |
648 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
649 | ||
3f7eeb86 PP |
650 | /* do this after setup_certs, because this can require the certs for verifying |
651 | OCSP information. */ | |
817d9f57 | 652 | rc = tls_expand_session_files(server_sni, cbinfo); |
7be682ca PP |
653 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
654 | ||
a799883d PP |
655 | rc = init_dh(ctx_sni, cbinfo->dhparam, NULL); |
656 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; | |
657 | ||
7be682ca | 658 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 659 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
660 | |
661 | return SSL_TLSEXT_ERR_OK; | |
662 | } | |
3bcbbbe2 | 663 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
664 | |
665 | ||
666 | ||
667 | ||
3f7eeb86 PP |
668 | #ifdef EXPERIMENTAL_OCSP |
669 | /************************************************* | |
670 | * Callback to handle OCSP Stapling * | |
671 | *************************************************/ | |
672 | ||
673 | /* Called when acting as server during the TLS session setup if the client | |
674 | requests OCSP information with a Certificate Status Request. | |
675 | ||
676 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
677 | project. | |
678 | ||
679 | */ | |
680 | ||
681 | static int | |
682 | tls_stapling_cb(SSL *s, void *arg) | |
683 | { | |
684 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
685 | uschar *response_der; | |
686 | int response_der_len; | |
687 | ||
688 | DEBUG(D_tls) debug_printf("Received TLS status request (OCSP stapling); %s response.\n", | |
689 | cbinfo->ocsp_response ? "have" : "lack"); | |
690 | if (!cbinfo->ocsp_response) | |
691 | return SSL_TLSEXT_ERR_NOACK; | |
692 | ||
693 | response_der = NULL; | |
694 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->ocsp_response, &response_der); | |
695 | if (response_der_len <= 0) | |
696 | return SSL_TLSEXT_ERR_NOACK; | |
697 | ||
698 | SSL_set_tlsext_status_ocsp_resp(ssl, response_der, response_der_len); | |
699 | return SSL_TLSEXT_ERR_OK; | |
700 | } | |
701 | ||
702 | #endif /* EXPERIMENTAL_OCSP */ | |
703 | ||
704 | ||
705 | ||
706 | ||
059ec3d9 PH |
707 | /************************************************* |
708 | * Initialize for TLS * | |
709 | *************************************************/ | |
710 | ||
711 | /* Called from both server and client code, to do preliminary initialization of | |
712 | the library. | |
713 | ||
714 | Arguments: | |
715 | host connected host, if client; NULL if server | |
716 | dhparam DH parameter file | |
717 | certificate certificate file | |
718 | privatekey private key | |
719 | addr address if client; NULL if server (for some randomness) | |
720 | ||
721 | Returns: OK/DEFER/FAIL | |
722 | */ | |
723 | ||
724 | static int | |
817d9f57 | 725 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 PP |
726 | uschar *privatekey, |
727 | #ifdef EXPERIMENTAL_OCSP | |
728 | uschar *ocsp_file, | |
729 | #endif | |
817d9f57 | 730 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 731 | { |
77bb000f | 732 | long init_options; |
7be682ca | 733 | int rc; |
77bb000f | 734 | BOOL okay; |
7be682ca PP |
735 | tls_ext_ctx_cb *cbinfo; |
736 | ||
737 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
738 | cbinfo->certificate = certificate; | |
739 | cbinfo->privatekey = privatekey; | |
3f7eeb86 PP |
740 | #ifdef EXPERIMENTAL_OCSP |
741 | cbinfo->ocsp_file = ocsp_file; | |
742 | #endif | |
7be682ca PP |
743 | cbinfo->dhparam = dhparam; |
744 | cbinfo->host = host; | |
77bb000f | 745 | |
059ec3d9 PH |
746 | SSL_load_error_strings(); /* basic set up */ |
747 | OpenSSL_add_ssl_algorithms(); | |
748 | ||
388d6564 | 749 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 750 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
751 | list of available digests. */ |
752 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 753 | #endif |
a0475b69 | 754 | |
f0f5a555 PP |
755 | /* Create a context. |
756 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
757 | negotiation in the different methods; as far as I can tell, the only | |
758 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
759 | when OpenSSL is built without SSLv2 support. | |
760 | By disabling with openssl_options, we can let admins re-enable with the | |
761 | existing knob. */ | |
059ec3d9 | 762 | |
817d9f57 | 763 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
764 | SSLv23_server_method() : SSLv23_client_method()); |
765 | ||
817d9f57 | 766 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
767 | |
768 | /* It turns out that we need to seed the random number generator this early in | |
769 | order to get the full complement of ciphers to work. It took me roughly a day | |
770 | of work to discover this by experiment. | |
771 | ||
772 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
773 | there. Otherwise, we have to make something up as best we can. Double check | |
774 | afterwards. */ | |
775 | ||
776 | if (!RAND_status()) | |
777 | { | |
778 | randstuff r; | |
9e3331ea | 779 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
780 | r.p = getpid(); |
781 | ||
782 | RAND_seed((uschar *)(&r), sizeof(r)); | |
783 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
784 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
785 | ||
786 | if (!RAND_status()) | |
7199e1ee | 787 | return tls_error(US"RAND_status", host, |
5ca6d115 | 788 | US"unable to seed random number generator"); |
059ec3d9 PH |
789 | } |
790 | ||
791 | /* Set up the information callback, which outputs if debugging is at a suitable | |
792 | level. */ | |
793 | ||
817d9f57 | 794 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 795 | |
c80c5570 | 796 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 797 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 798 | |
77bb000f PP |
799 | /* Apply administrator-supplied work-arounds. |
800 | Historically we applied just one requested option, | |
801 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
802 | moved to an administrator-controlled list of options to specify and | |
803 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 804 | |
77bb000f PP |
805 | No OpenSSL version number checks: the options we accept depend upon the |
806 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 807 | |
77bb000f PP |
808 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
809 | if (!okay) | |
73a46702 | 810 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
811 | |
812 | if (init_options) | |
813 | { | |
814 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 815 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
816 | return tls_error(string_sprintf( |
817 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
818 | } | |
819 | else | |
820 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
821 | |
822 | /* Initialize with DH parameters if supplied */ | |
823 | ||
817d9f57 | 824 | <<<<<<< HEAD |
a799883d | 825 | if (!init_dh(ctx, dhparam, host)) return DEFER; |
817d9f57 JH |
826 | ======= |
827 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; | |
828 | >>>>>>> Dual-tls - split management of TLS into in- and out-bound connection-handling. | |
059ec3d9 | 829 | |
3f7eeb86 | 830 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 831 | |
817d9f57 | 832 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 833 | if (rc != OK) return rc; |
c91535f3 | 834 | |
7be682ca | 835 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 836 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f0945ff PP |
837 | if (host == NULL) |
838 | { | |
3f7eeb86 PP |
839 | #ifdef EXPERIMENTAL_OCSP |
840 | /* We check ocsp_file, not ocsp_response, because we care about if | |
841 | the option exists, not what the current expansion might be, as SNI might | |
842 | change the certificate and OCSP file in use between now and the time the | |
843 | callback is invoked. */ | |
844 | if (cbinfo->ocsp_file) | |
845 | { | |
846 | SSL_CTX_set_tlsext_status_cb(ctx, tls_stapling_cb); | |
847 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
848 | } | |
849 | #endif | |
3f0945ff PP |
850 | /* We always do this, so that $tls_sni is available even if not used in |
851 | tls_certificate */ | |
817d9f57 JH |
852 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
853 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 854 | } |
7be682ca | 855 | #endif |
059ec3d9 PH |
856 | |
857 | /* Set up the RSA callback */ | |
858 | ||
817d9f57 | 859 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
860 | |
861 | /* Finally, set the timeout, and we are done */ | |
862 | ||
817d9f57 | 863 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 864 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 865 | |
817d9f57 | 866 | *cbp = cbinfo; |
7be682ca | 867 | |
059ec3d9 PH |
868 | return OK; |
869 | } | |
870 | ||
871 | ||
872 | ||
873 | ||
874 | /************************************************* | |
875 | * Get name of cipher in use * | |
876 | *************************************************/ | |
877 | ||
817d9f57 | 878 | /* |
059ec3d9 | 879 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
880 | buffer to use for answer |
881 | size of buffer | |
882 | pointer to number of bits for cipher | |
059ec3d9 PH |
883 | Returns: nothing |
884 | */ | |
885 | ||
886 | static void | |
817d9f57 | 887 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 888 | { |
57b3a7f5 PP |
889 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
890 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
891 | the accessor functions use const in the prototype. */ | |
892 | const SSL_CIPHER *c; | |
059ec3d9 | 893 | uschar *ver; |
059ec3d9 PH |
894 | |
895 | switch (ssl->session->ssl_version) | |
896 | { | |
897 | case SSL2_VERSION: | |
898 | ver = US"SSLv2"; | |
899 | break; | |
900 | ||
901 | case SSL3_VERSION: | |
902 | ver = US"SSLv3"; | |
903 | break; | |
904 | ||
905 | case TLS1_VERSION: | |
906 | ver = US"TLSv1"; | |
907 | break; | |
908 | ||
c80c5570 PP |
909 | #ifdef TLS1_1_VERSION |
910 | case TLS1_1_VERSION: | |
911 | ver = US"TLSv1.1"; | |
912 | break; | |
913 | #endif | |
914 | ||
915 | #ifdef TLS1_2_VERSION | |
916 | case TLS1_2_VERSION: | |
917 | ver = US"TLSv1.2"; | |
918 | break; | |
919 | #endif | |
920 | ||
059ec3d9 PH |
921 | default: |
922 | ver = US"UNKNOWN"; | |
923 | } | |
924 | ||
57b3a7f5 | 925 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 926 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 927 | |
817d9f57 JH |
928 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
929 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
930 | |
931 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
932 | } | |
933 | ||
934 | ||
935 | ||
936 | ||
937 | ||
938 | /************************************************* | |
939 | * Set up for verifying certificates * | |
940 | *************************************************/ | |
941 | ||
942 | /* Called by both client and server startup | |
943 | ||
944 | Arguments: | |
7be682ca | 945 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
946 | certs certs file or NULL |
947 | crl CRL file or NULL | |
948 | host NULL in a server; the remote host in a client | |
949 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
950 | otherwise passed as FALSE | |
951 | ||
952 | Returns: OK/DEFER/FAIL | |
953 | */ | |
954 | ||
955 | static int | |
7be682ca | 956 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional) |
059ec3d9 PH |
957 | { |
958 | uschar *expcerts, *expcrl; | |
959 | ||
960 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
961 | return DEFER; | |
962 | ||
963 | if (expcerts != NULL) | |
964 | { | |
965 | struct stat statbuf; | |
7be682ca | 966 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
7199e1ee | 967 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
968 | |
969 | if (Ustat(expcerts, &statbuf) < 0) | |
970 | { | |
971 | log_write(0, LOG_MAIN|LOG_PANIC, | |
972 | "failed to stat %s for certificates", expcerts); | |
973 | return DEFER; | |
974 | } | |
975 | else | |
976 | { | |
977 | uschar *file, *dir; | |
978 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
979 | { file = NULL; dir = expcerts; } | |
980 | else | |
981 | { file = expcerts; dir = NULL; } | |
982 | ||
983 | /* If a certificate file is empty, the next function fails with an | |
984 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
985 | certificates are recognized, but the error message is still misleading (it | |
986 | says no certificate was supplied.) But this is better. */ | |
987 | ||
988 | if ((file == NULL || statbuf.st_size > 0) && | |
7be682ca | 989 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) |
7199e1ee | 990 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 PH |
991 | |
992 | if (file != NULL) | |
993 | { | |
7be682ca | 994 | SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); |
059ec3d9 PH |
995 | } |
996 | } | |
997 | ||
998 | /* Handle a certificate revocation list. */ | |
999 | ||
1000 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1001 | ||
8b417f2c PH |
1002 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1003 | * merely reformatted it into the Exim code style.) | |
1004 | ||
1005 | * "From here I changed the code to add support for multiple crl's | |
1006 | * in pem format in one file or to support hashed directory entries in | |
1007 | * pem format instead of a file. This method now uses the library function | |
1008 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1009 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1010 | * itself in the verify callback." */ | |
1011 | ||
059ec3d9 PH |
1012 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1013 | if (expcrl != NULL && *expcrl != 0) | |
1014 | { | |
8b417f2c PH |
1015 | struct stat statbufcrl; |
1016 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1017 | { | |
1018 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1019 | "failed to stat %s for certificates revocation lists", expcrl); | |
1020 | return DEFER; | |
1021 | } | |
1022 | else | |
059ec3d9 | 1023 | { |
8b417f2c PH |
1024 | /* is it a file or directory? */ |
1025 | uschar *file, *dir; | |
7be682ca | 1026 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1027 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1028 | { |
8b417f2c PH |
1029 | file = NULL; |
1030 | dir = expcrl; | |
1031 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1032 | } |
1033 | else | |
1034 | { | |
8b417f2c PH |
1035 | file = expcrl; |
1036 | dir = NULL; | |
1037 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1038 | } |
8b417f2c | 1039 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1040 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1041 | |
1042 | /* setting the flags to check against the complete crl chain */ | |
1043 | ||
1044 | X509_STORE_set_flags(cvstore, | |
1045 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1046 | } |
059ec3d9 PH |
1047 | } |
1048 | ||
1049 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1050 | ||
1051 | /* If verification is optional, don't fail if no certificate */ | |
1052 | ||
7be682ca | 1053 | SSL_CTX_set_verify(sctx, |
059ec3d9 PH |
1054 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
1055 | verify_callback); | |
1056 | } | |
1057 | ||
1058 | return OK; | |
1059 | } | |
1060 | ||
1061 | ||
1062 | ||
1063 | /************************************************* | |
1064 | * Start a TLS session in a server * | |
1065 | *************************************************/ | |
1066 | ||
1067 | /* This is called when Exim is running as a server, after having received | |
1068 | the STARTTLS command. It must respond to that command, and then negotiate | |
1069 | a TLS session. | |
1070 | ||
1071 | Arguments: | |
1072 | require_ciphers allowed ciphers | |
1073 | ||
1074 | Returns: OK on success | |
1075 | DEFER for errors before the start of the negotiation | |
1076 | FAIL for errors during the negotation; the server can't | |
1077 | continue running. | |
1078 | */ | |
1079 | ||
1080 | int | |
17c76198 | 1081 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1082 | { |
1083 | int rc; | |
1084 | uschar *expciphers; | |
7be682ca | 1085 | tls_ext_ctx_cb *cbinfo; |
817d9f57 | 1086 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1087 | |
1088 | /* Check for previous activation */ | |
1089 | ||
817d9f57 | 1090 | if (tls_in.active >= 0) |
059ec3d9 | 1091 | { |
5ca6d115 | 1092 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1093 | smtp_printf("554 Already in TLS\r\n"); |
1094 | return FAIL; | |
1095 | } | |
1096 | ||
1097 | /* Initialize the SSL library. If it fails, it will already have logged | |
1098 | the error. */ | |
1099 | ||
817d9f57 | 1100 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
3f7eeb86 PP |
1101 | #ifdef EXPERIMENTAL_OCSP |
1102 | tls_ocsp_file, | |
1103 | #endif | |
817d9f57 | 1104 | NULL, &server_static_cbinfo); |
059ec3d9 | 1105 | if (rc != OK) return rc; |
817d9f57 | 1106 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1107 | |
1108 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1109 | return FAIL; | |
1110 | ||
1111 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1112 | were historically separated by underscores. So that I can use either form in my |
1113 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1114 | */ | |
059ec3d9 PH |
1115 | |
1116 | if (expciphers != NULL) | |
1117 | { | |
1118 | uschar *s = expciphers; | |
1119 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1120 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1121 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1122 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1123 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1124 | } |
1125 | ||
1126 | /* If this is a host for which certificate verification is mandatory or | |
1127 | optional, set up appropriately. */ | |
1128 | ||
817d9f57 | 1129 | tls_in.certificate_verified = FALSE; |
059ec3d9 PH |
1130 | verify_callback_called = FALSE; |
1131 | ||
1132 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1133 | { | |
817d9f57 | 1134 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, FALSE); |
059ec3d9 PH |
1135 | if (rc != OK) return rc; |
1136 | verify_optional = FALSE; | |
1137 | } | |
1138 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1139 | { | |
817d9f57 | 1140 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, TRUE); |
059ec3d9 PH |
1141 | if (rc != OK) return rc; |
1142 | verify_optional = TRUE; | |
1143 | } | |
1144 | ||
1145 | /* Prepare for new connection */ | |
1146 | ||
817d9f57 | 1147 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1148 | |
1149 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1150 | * | |
1151 | * With the SSL_clear(), we get strange interoperability bugs with | |
1152 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1153 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1154 | * | |
1155 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1156 | * session shutdown. In this case, we have a brand new object and there's no | |
1157 | * obvious reason to immediately clear it. I'm guessing that this was | |
1158 | * originally added because of incomplete initialisation which the clear fixed, | |
1159 | * in some historic release. | |
1160 | */ | |
059ec3d9 PH |
1161 | |
1162 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1163 | on connection, where outputting anything now upsets the clients and tends to | |
1164 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1165 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1166 | mode, the fflush() happens when smtp_getc() is called. */ | |
1167 | ||
817d9f57 JH |
1168 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1169 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1170 | { |
1171 | smtp_printf("220 TLS go ahead\r\n"); | |
1172 | fflush(smtp_out); | |
1173 | } | |
1174 | ||
1175 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1176 | that the OpenSSL library doesn't. */ | |
1177 | ||
817d9f57 JH |
1178 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1179 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1180 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1181 | |
1182 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1183 | ||
1184 | sigalrm_seen = FALSE; | |
1185 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1186 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1187 | alarm(0); |
1188 | ||
1189 | if (rc <= 0) | |
1190 | { | |
7199e1ee | 1191 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1192 | if (ERR_get_error() == 0) |
1193 | log_write(0, LOG_MAIN, | |
a053d125 | 1194 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1195 | return FAIL; |
1196 | } | |
1197 | ||
1198 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1199 | ||
1200 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1201 | and initialize things. */ | |
1202 | ||
817d9f57 JH |
1203 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1204 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1205 | |
1206 | DEBUG(D_tls) | |
1207 | { | |
1208 | uschar buf[2048]; | |
817d9f57 | 1209 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1210 | debug_printf("Shared ciphers: %s\n", buf); |
1211 | } | |
1212 | ||
1213 | ||
817d9f57 JH |
1214 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1215 | Client-side (tls_out) reads (seem to?) go via | |
1216 | smtp_read_response()/ip_recv(). | |
1217 | Hence no need to duplicate for _in and _out. | |
1218 | */ | |
059ec3d9 PH |
1219 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1220 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1221 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1222 | ||
1223 | receive_getc = tls_getc; | |
1224 | receive_ungetc = tls_ungetc; | |
1225 | receive_feof = tls_feof; | |
1226 | receive_ferror = tls_ferror; | |
58eb016e | 1227 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1228 | |
817d9f57 | 1229 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1230 | return OK; |
1231 | } | |
1232 | ||
1233 | ||
1234 | ||
1235 | ||
1236 | ||
1237 | /************************************************* | |
1238 | * Start a TLS session in a client * | |
1239 | *************************************************/ | |
1240 | ||
1241 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1242 | ||
1243 | Argument: | |
1244 | fd the fd of the connection | |
1245 | host connected host (for messages) | |
83da1223 | 1246 | addr the first address |
059ec3d9 PH |
1247 | dhparam DH parameter file |
1248 | certificate certificate file | |
1249 | privatekey private key file | |
3f0945ff | 1250 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1251 | verify_certs file for certificate verify |
1252 | crl file containing CRL | |
1253 | require_ciphers list of allowed ciphers | |
54c90be1 PP |
1254 | dh_min_bits minimum number of bits acceptable in server's DH prime |
1255 | (unused in OpenSSL) | |
83da1223 | 1256 | timeout startup timeout |
059ec3d9 PH |
1257 | |
1258 | Returns: OK on success | |
1259 | FAIL otherwise - note that tls_error() will not give DEFER | |
1260 | because this is not a server | |
1261 | */ | |
1262 | ||
1263 | int | |
1264 | tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, | |
3f0945ff PP |
1265 | uschar *certificate, uschar *privatekey, uschar *sni, |
1266 | uschar *verify_certs, uschar *crl, | |
54c90be1 | 1267 | uschar *require_ciphers, int dh_min_bits ARG_UNUSED, int timeout) |
059ec3d9 PH |
1268 | { |
1269 | static uschar txt[256]; | |
1270 | uschar *expciphers; | |
1271 | X509* server_cert; | |
1272 | int rc; | |
817d9f57 | 1273 | static uschar cipherbuf[256]; |
059ec3d9 | 1274 | |
817d9f57 | 1275 | rc = tls_init(&client_ctx, host, dhparam, certificate, privatekey, |
3f7eeb86 PP |
1276 | #ifdef EXPERIMENTAL_OCSP |
1277 | NULL, | |
1278 | #endif | |
817d9f57 | 1279 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1280 | if (rc != OK) return rc; |
1281 | ||
817d9f57 | 1282 | tls_out.certificate_verified = FALSE; |
059ec3d9 PH |
1283 | verify_callback_called = FALSE; |
1284 | ||
1285 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1286 | return FAIL; | |
1287 | ||
1288 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1289 | are separated by underscores. So that I can use either form in my tests, and | |
1290 | also for general convenience, we turn underscores into hyphens here. */ | |
1291 | ||
1292 | if (expciphers != NULL) | |
1293 | { | |
1294 | uschar *s = expciphers; | |
1295 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1296 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1297 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1298 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1299 | } |
1300 | ||
817d9f57 | 1301 | rc = setup_certs(client_ctx, verify_certs, crl, host, FALSE); |
059ec3d9 PH |
1302 | if (rc != OK) return rc; |
1303 | ||
817d9f57 JH |
1304 | if ((client_ssl = SSL_new(client_ctx)) == NULL) return tls_error(US"SSL_new", host, NULL); |
1305 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); | |
1306 | SSL_set_fd(client_ssl, fd); | |
1307 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 1308 | |
3f0945ff PP |
1309 | if (sni) |
1310 | { | |
817d9f57 | 1311 | if (!expand_check(sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 1312 | return FAIL; |
817d9f57 JH |
1313 | if (!Ustrlen(tls_out.sni)) |
1314 | tls_out.sni = NULL; | |
3f0945ff PP |
1315 | else |
1316 | { | |
35731706 | 1317 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
1318 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
1319 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
1320 | #else |
1321 | DEBUG(D_tls) | |
1322 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
1323 | tls_sni); | |
1324 | #endif | |
3f0945ff PP |
1325 | } |
1326 | } | |
1327 | ||
059ec3d9 PH |
1328 | /* There doesn't seem to be a built-in timeout on connection. */ |
1329 | ||
1330 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1331 | sigalrm_seen = FALSE; | |
1332 | alarm(timeout); | |
817d9f57 | 1333 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
1334 | alarm(0); |
1335 | ||
1336 | if (rc <= 0) | |
7199e1ee | 1337 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1338 | |
1339 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1340 | ||
453a6645 | 1341 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
817d9f57 | 1342 | server_cert = SSL_get_peer_certificate (client_ssl); |
453a6645 PP |
1343 | if (server_cert) |
1344 | { | |
817d9f57 | 1345 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), |
453a6645 | 1346 | CS txt, sizeof(txt)); |
817d9f57 | 1347 | tls_out.peerdn = txt; |
453a6645 PP |
1348 | } |
1349 | else | |
817d9f57 | 1350 | tls_out.peerdn = NULL; |
059ec3d9 | 1351 | |
817d9f57 JH |
1352 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
1353 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 1354 | |
817d9f57 | 1355 | tls_out.active = fd; |
059ec3d9 PH |
1356 | return OK; |
1357 | } | |
1358 | ||
1359 | ||
1360 | ||
1361 | ||
1362 | ||
1363 | /************************************************* | |
1364 | * TLS version of getc * | |
1365 | *************************************************/ | |
1366 | ||
1367 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1368 | it refills the buffer via the SSL reading function. | |
1369 | ||
1370 | Arguments: none | |
1371 | Returns: the next character or EOF | |
817d9f57 JH |
1372 | |
1373 | Only used by the server-side TLS. | |
059ec3d9 PH |
1374 | */ |
1375 | ||
1376 | int | |
1377 | tls_getc(void) | |
1378 | { | |
1379 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1380 | { | |
1381 | int error; | |
1382 | int inbytes; | |
1383 | ||
817d9f57 | 1384 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 1385 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
1386 | |
1387 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
1388 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
1389 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
1390 | alarm(0); |
1391 | ||
1392 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
1393 | closed down, not that the socket itself has been closed down. Revert to | |
1394 | non-SSL handling. */ | |
1395 | ||
1396 | if (error == SSL_ERROR_ZERO_RETURN) | |
1397 | { | |
1398 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1399 | ||
1400 | receive_getc = smtp_getc; | |
1401 | receive_ungetc = smtp_ungetc; | |
1402 | receive_feof = smtp_feof; | |
1403 | receive_ferror = smtp_ferror; | |
58eb016e | 1404 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1405 | |
817d9f57 JH |
1406 | SSL_free(server_ssl); |
1407 | server_ssl = NULL; | |
1408 | tls_in.active = -1; | |
1409 | tls_in.bits = 0; | |
1410 | tls_in.cipher = NULL; | |
1411 | tls_in.peerdn = NULL; | |
1412 | tls_in.sni = NULL; | |
059ec3d9 PH |
1413 | |
1414 | return smtp_getc(); | |
1415 | } | |
1416 | ||
1417 | /* Handle genuine errors */ | |
1418 | ||
ba084640 PP |
1419 | else if (error == SSL_ERROR_SSL) |
1420 | { | |
1421 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 1422 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
1423 | ssl_xfer_error = 1; |
1424 | return EOF; | |
1425 | } | |
1426 | ||
059ec3d9 PH |
1427 | else if (error != SSL_ERROR_NONE) |
1428 | { | |
1429 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
1430 | ssl_xfer_error = 1; | |
1431 | return EOF; | |
1432 | } | |
c80c5570 | 1433 | |
80a47a2c TK |
1434 | #ifndef DISABLE_DKIM |
1435 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
1436 | #endif | |
059ec3d9 PH |
1437 | ssl_xfer_buffer_hwm = inbytes; |
1438 | ssl_xfer_buffer_lwm = 0; | |
1439 | } | |
1440 | ||
1441 | /* Something in the buffer; return next uschar */ | |
1442 | ||
1443 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1444 | } | |
1445 | ||
1446 | ||
1447 | ||
1448 | /************************************************* | |
1449 | * Read bytes from TLS channel * | |
1450 | *************************************************/ | |
1451 | ||
1452 | /* | |
1453 | Arguments: | |
1454 | buff buffer of data | |
1455 | len size of buffer | |
1456 | ||
1457 | Returns: the number of bytes read | |
1458 | -1 after a failed read | |
817d9f57 JH |
1459 | |
1460 | Only used by the client-side TLS. | |
059ec3d9 PH |
1461 | */ |
1462 | ||
1463 | int | |
1464 | tls_read(uschar *buff, size_t len) | |
1465 | { | |
1466 | int inbytes; | |
1467 | int error; | |
1468 | ||
817d9f57 | 1469 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", client_ssl, |
c80c5570 | 1470 | buff, (unsigned int)len); |
059ec3d9 | 1471 | |
817d9f57 JH |
1472 | inbytes = SSL_read(client_ssl, CS buff, len); |
1473 | error = SSL_get_error(client_ssl, inbytes); | |
059ec3d9 PH |
1474 | |
1475 | if (error == SSL_ERROR_ZERO_RETURN) | |
1476 | { | |
1477 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1478 | return -1; | |
1479 | } | |
1480 | else if (error != SSL_ERROR_NONE) | |
1481 | { | |
1482 | return -1; | |
1483 | } | |
1484 | ||
1485 | return inbytes; | |
1486 | } | |
1487 | ||
1488 | ||
1489 | ||
1490 | ||
1491 | ||
1492 | /************************************************* | |
1493 | * Write bytes down TLS channel * | |
1494 | *************************************************/ | |
1495 | ||
1496 | /* | |
1497 | Arguments: | |
817d9f57 | 1498 | is_server channel specifier |
059ec3d9 PH |
1499 | buff buffer of data |
1500 | len number of bytes | |
1501 | ||
1502 | Returns: the number of bytes after a successful write, | |
1503 | -1 after a failed write | |
817d9f57 JH |
1504 | |
1505 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1506 | */ |
1507 | ||
1508 | int | |
817d9f57 | 1509 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
1510 | { |
1511 | int outbytes; | |
1512 | int error; | |
1513 | int left = len; | |
817d9f57 | 1514 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 1515 | |
c80c5570 | 1516 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
1517 | while (left > 0) |
1518 | { | |
c80c5570 | 1519 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
1520 | outbytes = SSL_write(ssl, CS buff, left); |
1521 | error = SSL_get_error(ssl, outbytes); | |
1522 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1523 | switch (error) | |
1524 | { | |
1525 | case SSL_ERROR_SSL: | |
1526 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1527 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1528 | return -1; | |
1529 | ||
1530 | case SSL_ERROR_NONE: | |
1531 | left -= outbytes; | |
1532 | buff += outbytes; | |
1533 | break; | |
1534 | ||
1535 | case SSL_ERROR_ZERO_RETURN: | |
1536 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1537 | return -1; | |
1538 | ||
817d9f57 JH |
1539 | case SSL_ERROR_SYSCALL: |
1540 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
1541 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
1542 | strerror(errno)); | |
1543 | ||
059ec3d9 PH |
1544 | default: |
1545 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1546 | return -1; | |
1547 | } | |
1548 | } | |
1549 | return len; | |
1550 | } | |
1551 | ||
1552 | ||
1553 | ||
1554 | /************************************************* | |
1555 | * Close down a TLS session * | |
1556 | *************************************************/ | |
1557 | ||
1558 | /* This is also called from within a delivery subprocess forked from the | |
1559 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1560 | would tamper with the SSL session in the parent process). | |
1561 | ||
1562 | Arguments: TRUE if SSL_shutdown is to be called | |
1563 | Returns: nothing | |
817d9f57 JH |
1564 | |
1565 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1566 | */ |
1567 | ||
1568 | void | |
817d9f57 | 1569 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1570 | { |
817d9f57 JH |
1571 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
1572 | ||
1573 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
1574 | |
1575 | if (shutdown) | |
1576 | { | |
1577 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 1578 | SSL_shutdown(*sslp); |
059ec3d9 PH |
1579 | } |
1580 | ||
817d9f57 JH |
1581 | SSL_free(*sslp); |
1582 | *sslp = NULL; | |
059ec3d9 | 1583 | |
817d9f57 | 1584 | *fdp = -1; |
059ec3d9 PH |
1585 | } |
1586 | ||
36f12725 NM |
1587 | |
1588 | ||
1589 | ||
3375e053 PP |
1590 | /************************************************* |
1591 | * Let tls_require_ciphers be checked at startup * | |
1592 | *************************************************/ | |
1593 | ||
1594 | /* The tls_require_ciphers option, if set, must be something which the | |
1595 | library can parse. | |
1596 | ||
1597 | Returns: NULL on success, or error message | |
1598 | */ | |
1599 | ||
1600 | uschar * | |
1601 | tls_validate_require_cipher(void) | |
1602 | { | |
1603 | SSL_CTX *ctx; | |
1604 | uschar *s, *expciphers, *err; | |
1605 | ||
1606 | /* this duplicates from tls_init(), we need a better "init just global | |
1607 | state, for no specific purpose" singleton function of our own */ | |
1608 | ||
1609 | SSL_load_error_strings(); | |
1610 | OpenSSL_add_ssl_algorithms(); | |
1611 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
1612 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
1613 | list of available digests. */ | |
1614 | EVP_add_digest(EVP_sha256()); | |
1615 | #endif | |
1616 | ||
1617 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1618 | return NULL; | |
1619 | ||
1620 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1621 | return US"failed to expand tls_require_ciphers"; | |
1622 | ||
1623 | if (!(expciphers && *expciphers)) | |
1624 | return NULL; | |
1625 | ||
1626 | /* normalisation ripped from above */ | |
1627 | s = expciphers; | |
1628 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1629 | ||
1630 | err = NULL; | |
1631 | ||
1632 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
1633 | if (!ctx) | |
1634 | { | |
1635 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1636 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
1637 | } | |
1638 | ||
1639 | DEBUG(D_tls) | |
1640 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1641 | ||
1642 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
1643 | { | |
1644 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1645 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
1646 | } | |
1647 | ||
1648 | SSL_CTX_free(ctx); | |
1649 | ||
1650 | return err; | |
1651 | } | |
1652 | ||
1653 | ||
1654 | ||
1655 | ||
36f12725 NM |
1656 | /************************************************* |
1657 | * Report the library versions. * | |
1658 | *************************************************/ | |
1659 | ||
1660 | /* There have historically been some issues with binary compatibility in | |
1661 | OpenSSL libraries; if Exim (like many other applications) is built against | |
1662 | one version of OpenSSL but the run-time linker picks up another version, | |
1663 | it can result in serious failures, including crashing with a SIGSEGV. So | |
1664 | report the version found by the compiler and the run-time version. | |
1665 | ||
1666 | Arguments: a FILE* to print the results to | |
1667 | Returns: nothing | |
1668 | */ | |
1669 | ||
1670 | void | |
1671 | tls_version_report(FILE *f) | |
1672 | { | |
754a0503 PP |
1673 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
1674 | " Runtime: %s\n", | |
1675 | OPENSSL_VERSION_TEXT, | |
1676 | SSLeay_version(SSLEAY_VERSION)); | |
36f12725 NM |
1677 | } |
1678 | ||
9e3331ea TK |
1679 | |
1680 | ||
1681 | ||
1682 | /************************************************* | |
17c76198 | 1683 | * Random number generation * |
9e3331ea TK |
1684 | *************************************************/ |
1685 | ||
1686 | /* Pseudo-random number generation. The result is not expected to be | |
1687 | cryptographically strong but not so weak that someone will shoot themselves | |
1688 | in the foot using it as a nonce in input in some email header scheme or | |
1689 | whatever weirdness they'll twist this into. The result should handle fork() | |
1690 | and avoid repeating sequences. OpenSSL handles that for us. | |
1691 | ||
1692 | Arguments: | |
1693 | max range maximum | |
1694 | Returns a random number in range [0, max-1] | |
1695 | */ | |
1696 | ||
1697 | int | |
17c76198 | 1698 | vaguely_random_number(int max) |
9e3331ea TK |
1699 | { |
1700 | unsigned int r; | |
1701 | int i, needed_len; | |
1702 | uschar *p; | |
1703 | uschar smallbuf[sizeof(r)]; | |
1704 | ||
1705 | if (max <= 1) | |
1706 | return 0; | |
1707 | ||
1708 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ | |
1709 | if (!RAND_status()) | |
1710 | { | |
1711 | randstuff r; | |
1712 | gettimeofday(&r.tv, NULL); | |
1713 | r.p = getpid(); | |
1714 | ||
1715 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1716 | } | |
1717 | /* We're after pseudo-random, not random; if we still don't have enough data | |
1718 | in the internal PRNG then our options are limited. We could sleep and hope | |
1719 | for entropy to come along (prayer technique) but if the system is so depleted | |
1720 | in the first place then something is likely to just keep taking it. Instead, | |
1721 | we'll just take whatever little bit of pseudo-random we can still manage to | |
1722 | get. */ | |
1723 | ||
1724 | needed_len = sizeof(r); | |
1725 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1726 | asked for a number less than 10. */ | |
1727 | for (r = max, i = 0; r; ++i) | |
1728 | r >>= 1; | |
1729 | i = (i + 7) / 8; | |
1730 | if (i < needed_len) | |
1731 | needed_len = i; | |
1732 | ||
1733 | /* We do not care if crypto-strong */ | |
17c76198 PP |
1734 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
1735 | if (i < 0) | |
1736 | { | |
1737 | DEBUG(D_all) | |
1738 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
1739 | return vaguely_random_number_fallback(max); | |
1740 | } | |
1741 | ||
9e3331ea TK |
1742 | r = 0; |
1743 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
1744 | { | |
1745 | r *= 256; | |
1746 | r += *p; | |
1747 | } | |
1748 | ||
1749 | /* We don't particularly care about weighted results; if someone wants | |
1750 | smooth distribution and cares enough then they should submit a patch then. */ | |
1751 | return r % max; | |
1752 | } | |
1753 | ||
77bb000f PP |
1754 | |
1755 | ||
1756 | ||
1757 | /************************************************* | |
1758 | * OpenSSL option parse * | |
1759 | *************************************************/ | |
1760 | ||
1761 | /* Parse one option for tls_openssl_options_parse below | |
1762 | ||
1763 | Arguments: | |
1764 | name one option name | |
1765 | value place to store a value for it | |
1766 | Returns success or failure in parsing | |
1767 | */ | |
1768 | ||
1769 | struct exim_openssl_option { | |
1770 | uschar *name; | |
1771 | long value; | |
1772 | }; | |
1773 | /* We could use a macro to expand, but we need the ifdef and not all the | |
1774 | options document which version they were introduced in. Policylet: include | |
1775 | all options unless explicitly for DTLS, let the administrator choose which | |
1776 | to apply. | |
1777 | ||
1778 | This list is current as of: | |
c80c5570 | 1779 | ==> 1.0.1b <== */ |
77bb000f PP |
1780 | static struct exim_openssl_option exim_openssl_options[] = { |
1781 | /* KEEP SORTED ALPHABETICALLY! */ | |
1782 | #ifdef SSL_OP_ALL | |
73a46702 | 1783 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
1784 | #endif |
1785 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 1786 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
1787 | #endif |
1788 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 1789 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
1790 | #endif |
1791 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 1792 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
1793 | #endif |
1794 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 1795 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
1796 | #endif |
1797 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 1798 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
1799 | #endif |
1800 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 1801 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
1802 | #endif |
1803 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 1804 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
1805 | #endif |
1806 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 1807 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
1808 | #endif |
1809 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 1810 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
1811 | #endif |
1812 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 1813 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 1814 | #endif |
c80c5570 PP |
1815 | #ifdef SSL_OP_NO_COMPRESSION |
1816 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
1817 | #endif | |
77bb000f | 1818 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 1819 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 1820 | #endif |
c0c7b2da PP |
1821 | #ifdef SSL_OP_NO_SSLv2 |
1822 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
1823 | #endif | |
1824 | #ifdef SSL_OP_NO_SSLv3 | |
1825 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
1826 | #endif | |
1827 | #ifdef SSL_OP_NO_TICKET | |
1828 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
1829 | #endif | |
1830 | #ifdef SSL_OP_NO_TLSv1 | |
1831 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
1832 | #endif | |
c80c5570 PP |
1833 | #ifdef SSL_OP_NO_TLSv1_1 |
1834 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
1835 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
1836 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
1837 | #else | |
1838 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
1839 | #endif | |
1840 | #endif | |
1841 | #ifdef SSL_OP_NO_TLSv1_2 | |
1842 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
1843 | #endif | |
77bb000f | 1844 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 1845 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
1846 | #endif |
1847 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 1848 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
1849 | #endif |
1850 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 1851 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
1852 | #endif |
1853 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 1854 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
1855 | #endif |
1856 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 1857 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
1858 | #endif |
1859 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 1860 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
1861 | #endif |
1862 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 1863 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
1864 | #endif |
1865 | }; | |
1866 | static int exim_openssl_options_size = | |
1867 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
1868 | ||
c80c5570 | 1869 | |
77bb000f PP |
1870 | static BOOL |
1871 | tls_openssl_one_option_parse(uschar *name, long *value) | |
1872 | { | |
1873 | int first = 0; | |
1874 | int last = exim_openssl_options_size; | |
1875 | while (last > first) | |
1876 | { | |
1877 | int middle = (first + last)/2; | |
1878 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
1879 | if (c == 0) | |
1880 | { | |
1881 | *value = exim_openssl_options[middle].value; | |
1882 | return TRUE; | |
1883 | } | |
1884 | else if (c > 0) | |
1885 | first = middle + 1; | |
1886 | else | |
1887 | last = middle; | |
1888 | } | |
1889 | return FALSE; | |
1890 | } | |
1891 | ||
1892 | ||
1893 | ||
1894 | ||
1895 | /************************************************* | |
1896 | * OpenSSL option parsing logic * | |
1897 | *************************************************/ | |
1898 | ||
1899 | /* OpenSSL has a number of compatibility options which an administrator might | |
1900 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
1901 | we look like log_selector. | |
1902 | ||
1903 | Arguments: | |
1904 | option_spec the administrator-supplied string of options | |
1905 | results ptr to long storage for the options bitmap | |
1906 | Returns success or failure | |
1907 | */ | |
1908 | ||
1909 | BOOL | |
1910 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
1911 | { | |
1912 | long result, item; | |
1913 | uschar *s, *end; | |
1914 | uschar keep_c; | |
1915 | BOOL adding, item_parsed; | |
1916 | ||
0e944a0d | 1917 | result = 0L; |
b1770b6e | 1918 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 1919 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
1920 | #ifdef SSL_OP_NO_SSLv2 |
1921 | result |= SSL_OP_NO_SSLv2; | |
1922 | #endif | |
77bb000f PP |
1923 | |
1924 | if (option_spec == NULL) | |
1925 | { | |
1926 | *results = result; | |
1927 | return TRUE; | |
1928 | } | |
1929 | ||
1930 | for (s=option_spec; *s != '\0'; /**/) | |
1931 | { | |
1932 | while (isspace(*s)) ++s; | |
1933 | if (*s == '\0') | |
1934 | break; | |
1935 | if (*s != '+' && *s != '-') | |
1936 | { | |
1937 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 1938 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
1939 | return FALSE; |
1940 | } | |
1941 | adding = *s++ == '+'; | |
1942 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
1943 | keep_c = *end; | |
1944 | *end = '\0'; | |
1945 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
1946 | if (!item_parsed) | |
1947 | { | |
0e944a0d | 1948 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
1949 | return FALSE; |
1950 | } | |
1951 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
1952 | adding ? "adding" : "removing", result, item, s); | |
1953 | if (adding) | |
1954 | result |= item; | |
1955 | else | |
1956 | result &= ~item; | |
1957 | *end = keep_c; | |
1958 | s = end; | |
1959 | } | |
1960 | ||
1961 | *results = result; | |
1962 | return TRUE; | |
1963 | } | |
1964 | ||
059ec3d9 | 1965 | /* End of tls-openssl.c */ |