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 | ||
a2ff477a JH |
45 | static BOOL client_verify_callback_called = FALSE; |
46 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
47 | static const uschar *sid_ctx = US"exim"; |
48 | ||
817d9f57 JH |
49 | static SSL_CTX *client_ctx = NULL; |
50 | static SSL_CTX *server_ctx = NULL; | |
51 | static SSL *client_ssl = NULL; | |
52 | static SSL *server_ssl = NULL; | |
35731706 | 53 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
54 | static SSL_CTX *client_sni = NULL; |
55 | static SSL_CTX *server_sni = NULL; | |
35731706 | 56 | #endif |
059ec3d9 PH |
57 | |
58 | static char ssl_errstring[256]; | |
59 | ||
60 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
61 | static BOOL client_verify_optional = FALSE; |
62 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 63 | |
7be682ca | 64 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
65 | |
66 | ||
7be682ca PP |
67 | typedef struct tls_ext_ctx_cb { |
68 | uschar *certificate; | |
69 | uschar *privatekey; | |
3f7eeb86 PP |
70 | #ifdef EXPERIMENTAL_OCSP |
71 | uschar *ocsp_file; | |
72 | uschar *ocsp_file_expanded; | |
73 | OCSP_RESPONSE *ocsp_response; | |
74 | #endif | |
7be682ca PP |
75 | uschar *dhparam; |
76 | /* these are cached from first expand */ | |
77 | uschar *server_cipher_list; | |
78 | /* only passed down to tls_error: */ | |
79 | host_item *host; | |
80 | } tls_ext_ctx_cb; | |
81 | ||
82 | /* should figure out a cleanup of API to handle state preserved per | |
83 | implementation, for various reasons, which can be void * in the APIs. | |
84 | For now, we hack around it. */ | |
817d9f57 JH |
85 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
86 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
87 | |
88 | static int | |
a2ff477a | 89 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, BOOL client); |
059ec3d9 | 90 | |
3f7eeb86 | 91 | /* Callbacks */ |
3bcbbbe2 | 92 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 93 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 94 | #endif |
3f7eeb86 PP |
95 | #ifdef EXPERIMENTAL_OCSP |
96 | static int tls_stapling_cb(SSL *s, void *arg); | |
97 | #endif | |
98 | ||
059ec3d9 PH |
99 | |
100 | /************************************************* | |
101 | * Handle TLS error * | |
102 | *************************************************/ | |
103 | ||
104 | /* Called from lots of places when errors occur before actually starting to do | |
105 | the TLS handshake, that is, while the session is still in clear. Always returns | |
106 | DEFER for a server and FAIL for a client so that most calls can use "return | |
107 | tls_error(...)" to do this processing and then give an appropriate return. A | |
108 | single function is used for both server and client, because it is called from | |
109 | some shared functions. | |
110 | ||
111 | Argument: | |
112 | prefix text to include in the logged error | |
113 | host NULL if setting up a server; | |
114 | the connected host if setting up a client | |
7199e1ee | 115 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
116 | |
117 | Returns: OK/DEFER/FAIL | |
118 | */ | |
119 | ||
120 | static int | |
7199e1ee | 121 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 122 | { |
7199e1ee TF |
123 | if (msg == NULL) |
124 | { | |
125 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 126 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
127 | } |
128 | ||
059ec3d9 PH |
129 | if (host == NULL) |
130 | { | |
7199e1ee | 131 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 132 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
133 | conn_info += 5; |
134 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
135 | conn_info, prefix, msg); | |
059ec3d9 PH |
136 | return DEFER; |
137 | } | |
138 | else | |
139 | { | |
140 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
7199e1ee | 141 | host->name, host->address, prefix, msg); |
059ec3d9 PH |
142 | return FAIL; |
143 | } | |
144 | } | |
145 | ||
146 | ||
147 | ||
148 | /************************************************* | |
149 | * Callback to generate RSA key * | |
150 | *************************************************/ | |
151 | ||
152 | /* | |
153 | Arguments: | |
154 | s SSL connection | |
155 | export not used | |
156 | keylength keylength | |
157 | ||
158 | Returns: pointer to generated key | |
159 | */ | |
160 | ||
161 | static RSA * | |
162 | rsa_callback(SSL *s, int export, int keylength) | |
163 | { | |
164 | RSA *rsa_key; | |
165 | export = export; /* Shut picky compilers up */ | |
166 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
167 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
168 | if (rsa_key == NULL) | |
169 | { | |
170 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
171 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
172 | ssl_errstring); | |
173 | return NULL; | |
174 | } | |
175 | return rsa_key; | |
176 | } | |
177 | ||
178 | ||
179 | ||
180 | ||
181 | /************************************************* | |
182 | * Callback for verification * | |
183 | *************************************************/ | |
184 | ||
185 | /* The SSL library does certificate verification if set up to do so. This | |
186 | callback has the current yes/no state is in "state". If verification succeeded, | |
187 | we set up the tls_peerdn string. If verification failed, what happens depends | |
188 | on whether the client is required to present a verifiable certificate or not. | |
189 | ||
190 | If verification is optional, we change the state to yes, but still log the | |
191 | verification error. For some reason (it really would help to have proper | |
192 | documentation of OpenSSL), this callback function then gets called again, this | |
193 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
194 | value, but we must take care not to set the private verified flag on the second | |
195 | time through. | |
196 | ||
197 | Note: this function is not called if the client fails to present a certificate | |
198 | when asked. We get here only if a certificate has been received. Handling of | |
199 | optional verification for this case is done when requesting SSL to verify, by | |
200 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
201 | ||
202 | Arguments: | |
203 | state current yes/no state as 1/0 | |
204 | x509ctx certificate information. | |
a2ff477a | 205 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
206 | |
207 | Returns: 1 if verified, 0 if not | |
208 | */ | |
209 | ||
210 | static int | |
a2ff477a | 211 | verify_callback(int state, X509_STORE_CTX *x509ctx, BOOL client) |
059ec3d9 PH |
212 | { |
213 | static uschar txt[256]; | |
a2ff477a JH |
214 | tls_support * tlsp; |
215 | BOOL * calledp; | |
216 | BOOL * optionalp; | |
217 | ||
218 | if (client) | |
219 | { | |
220 | tlsp= &tls_out; | |
221 | calledp= &client_verify_callback_called; | |
222 | optionalp= &client_verify_optional; | |
223 | } | |
224 | else | |
225 | { | |
226 | tlsp= &tls_in; | |
227 | calledp= &server_verify_callback_called; | |
228 | optionalp= &server_verify_optional; | |
229 | } | |
059ec3d9 PH |
230 | |
231 | X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert), | |
232 | CS txt, sizeof(txt)); | |
233 | ||
234 | if (state == 0) | |
235 | { | |
236 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
237 | x509ctx->error_depth, | |
238 | X509_verify_cert_error_string(x509ctx->error), | |
239 | txt); | |
a2ff477a JH |
240 | tlsp->certificate_verified = FALSE; |
241 | *calledp = TRUE; | |
242 | if (!*optionalp) return 0; /* reject */ | |
059ec3d9 PH |
243 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
244 | "tls_try_verify_hosts)\n"); | |
245 | return 1; /* accept */ | |
246 | } | |
247 | ||
248 | if (x509ctx->error_depth != 0) | |
249 | { | |
250 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n", | |
251 | x509ctx->error_depth, txt); | |
252 | } | |
253 | else | |
254 | { | |
255 | DEBUG(D_tls) debug_printf("SSL%s peer: %s\n", | |
a2ff477a JH |
256 | *calledp ? "" : " authenticated", txt); |
257 | tlsp->peerdn = txt; | |
059ec3d9 PH |
258 | } |
259 | ||
a2ff477a JH |
260 | if (!*calledp) tlsp->certificate_verified = TRUE; |
261 | *calledp = TRUE; | |
059ec3d9 PH |
262 | |
263 | return 1; /* accept */ | |
264 | } | |
265 | ||
a2ff477a JH |
266 | static int |
267 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
268 | { | |
269 | return verify_callback(state, x509ctx, TRUE); | |
270 | } | |
271 | ||
272 | static int | |
273 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
274 | { | |
275 | return verify_callback(state, x509ctx, FALSE); | |
276 | } | |
277 | ||
059ec3d9 PH |
278 | |
279 | ||
280 | /************************************************* | |
281 | * Information callback * | |
282 | *************************************************/ | |
283 | ||
284 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
285 | are doing. We copy the string to the debugging output when TLS debugging has |
286 | been requested. | |
059ec3d9 PH |
287 | |
288 | Arguments: | |
289 | s the SSL connection | |
290 | where | |
291 | ret | |
292 | ||
293 | Returns: nothing | |
294 | */ | |
295 | ||
296 | static void | |
297 | info_callback(SSL *s, int where, int ret) | |
298 | { | |
299 | where = where; | |
300 | ret = ret; | |
301 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
302 | } | |
303 | ||
304 | ||
305 | ||
306 | /************************************************* | |
307 | * Initialize for DH * | |
308 | *************************************************/ | |
309 | ||
310 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
311 | ||
312 | Arguments: | |
a799883d | 313 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 314 | host connected host, if client; NULL if server |
059ec3d9 PH |
315 | |
316 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
317 | */ | |
318 | ||
319 | static BOOL | |
817d9f57 | 320 | <<<<<<< HEAD |
a799883d | 321 | init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host) |
817d9f57 JH |
322 | ======= |
323 | init_dh(SSL_CTX *ctx, uschar *dhparam, host_item *host) | |
324 | >>>>>>> Dual-tls - split management of TLS into in- and out-bound connection-handling. | |
059ec3d9 | 325 | { |
059ec3d9 PH |
326 | BIO *bio; |
327 | DH *dh; | |
328 | uschar *dhexpanded; | |
a799883d | 329 | const char *pem; |
059ec3d9 PH |
330 | |
331 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
332 | return FALSE; | |
333 | ||
a799883d | 334 | if (dhexpanded == NULL || *dhexpanded == '\0') |
059ec3d9 | 335 | { |
a799883d | 336 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
059ec3d9 | 337 | } |
a799883d | 338 | else if (dhexpanded[0] == '/') |
059ec3d9 | 339 | { |
a799883d PP |
340 | bio = BIO_new_file(CS dhexpanded, "r"); |
341 | if (bio == NULL) | |
059ec3d9 | 342 | { |
7199e1ee | 343 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
344 | host, US strerror(errno)); |
345 | return FALSE; | |
059ec3d9 | 346 | } |
a799883d PP |
347 | } |
348 | else | |
349 | { | |
350 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 351 | { |
a799883d PP |
352 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
353 | return TRUE; | |
059ec3d9 | 354 | } |
a799883d PP |
355 | |
356 | pem = std_dh_prime_named(dhexpanded); | |
357 | if (!pem) | |
358 | { | |
359 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
360 | host, US strerror(errno)); | |
361 | return FALSE; | |
362 | } | |
363 | bio = BIO_new_mem_buf(CS pem, -1); | |
364 | } | |
365 | ||
366 | dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL); | |
367 | if (dh == NULL) | |
368 | { | |
059ec3d9 | 369 | BIO_free(bio); |
a799883d PP |
370 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
371 | host, NULL); | |
372 | return FALSE; | |
373 | } | |
374 | ||
375 | /* Even if it is larger, we silently return success rather than cause things | |
376 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
377 | * debatable choice. */ | |
378 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
379 | { | |
380 | DEBUG(D_tls) | |
381 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
382 | 8*DH_size(dh), tls_dh_max_bits); | |
383 | } | |
384 | else | |
385 | { | |
386 | SSL_CTX_set_tmp_dh(sctx, dh); | |
387 | DEBUG(D_tls) | |
388 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
389 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
390 | } |
391 | ||
a799883d PP |
392 | DH_free(dh); |
393 | BIO_free(bio); | |
394 | ||
395 | return TRUE; | |
059ec3d9 PH |
396 | } |
397 | ||
398 | ||
399 | ||
400 | ||
3f7eeb86 PP |
401 | #ifdef EXPERIMENTAL_OCSP |
402 | /************************************************* | |
403 | * Load OCSP information into state * | |
404 | *************************************************/ | |
405 | ||
406 | /* Called to load the OCSP response from the given file into memory, once | |
407 | caller has determined this is needed. Checks validity. Debugs a message | |
408 | if invalid. | |
409 | ||
410 | ASSUMES: single response, for single cert. | |
411 | ||
412 | Arguments: | |
413 | sctx the SSL_CTX* to update | |
414 | cbinfo various parts of session state | |
415 | expanded the filename putatively holding an OCSP response | |
416 | ||
417 | */ | |
418 | ||
419 | static void | |
420 | ocsp_load_response(SSL_CTX *sctx, | |
421 | tls_ext_ctx_cb *cbinfo, | |
422 | const uschar *expanded) | |
423 | { | |
424 | BIO *bio; | |
425 | OCSP_RESPONSE *resp; | |
426 | OCSP_BASICRESP *basic_response; | |
427 | OCSP_SINGLERESP *single_response; | |
428 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
429 | X509_STORE *store; | |
430 | unsigned long verify_flags; | |
431 | int status, reason, i; | |
432 | ||
433 | cbinfo->ocsp_file_expanded = string_copy(expanded); | |
434 | if (cbinfo->ocsp_response) | |
435 | { | |
436 | OCSP_RESPONSE_free(cbinfo->ocsp_response); | |
437 | cbinfo->ocsp_response = NULL; | |
438 | } | |
439 | ||
440 | bio = BIO_new_file(CS cbinfo->ocsp_file_expanded, "rb"); | |
441 | if (!bio) | |
442 | { | |
443 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
444 | cbinfo->ocsp_file_expanded); | |
445 | return; | |
446 | } | |
447 | ||
448 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
449 | BIO_free(bio); | |
450 | if (!resp) | |
451 | { | |
452 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
453 | return; | |
454 | } | |
455 | ||
456 | status = OCSP_response_status(resp); | |
457 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
458 | { | |
459 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
460 | OCSP_response_status_str(status), status); | |
461 | return; | |
462 | } | |
463 | ||
464 | basic_response = OCSP_response_get1_basic(resp); | |
465 | if (!basic_response) | |
466 | { | |
467 | DEBUG(D_tls) | |
468 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
469 | return; | |
470 | } | |
471 | ||
472 | store = SSL_CTX_get_cert_store(sctx); | |
473 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
474 | ||
475 | /* May need to expose ability to adjust those flags? | |
476 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
477 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
478 | ||
479 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
480 | if (i <= 0) | |
481 | { | |
482 | DEBUG(D_tls) { | |
483 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
484 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
485 | } | |
486 | return; | |
487 | } | |
488 | ||
489 | /* Here's the simplifying assumption: there's only one response, for the | |
490 | one certificate we use, and nothing for anything else in a chain. If this | |
491 | proves false, we need to extract a cert id from our issued cert | |
492 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
493 | right cert in the stack and then calls OCSP_single_get0_status()). | |
494 | ||
495 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
496 | single_response = OCSP_resp_get0(basic_response, 0); | |
497 | if (!single_response) | |
498 | { | |
499 | DEBUG(D_tls) | |
500 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
501 | return; | |
502 | } | |
503 | ||
504 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
505 | /* how does this status differ from the one above? */ | |
506 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
507 | { | |
508 | DEBUG(D_tls) debug_printf("OCSP response not valid (take 2): %s (%d)\n", | |
509 | OCSP_response_status_str(status), status); | |
510 | return; | |
511 | } | |
512 | ||
513 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
514 | { | |
515 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
516 | return; | |
517 | } | |
518 | ||
519 | cbinfo->ocsp_response = resp; | |
520 | } | |
521 | #endif | |
522 | ||
523 | ||
524 | ||
525 | ||
7be682ca PP |
526 | /************************************************* |
527 | * Expand key and cert file specs * | |
528 | *************************************************/ | |
529 | ||
530 | /* Called once during tls_init and possibly againt during TLS setup, for a | |
531 | new context, if Server Name Indication was used and tls_sni was seen in | |
532 | the certificate string. | |
533 | ||
534 | Arguments: | |
535 | sctx the SSL_CTX* to update | |
536 | cbinfo various parts of session state | |
537 | ||
538 | Returns: OK/DEFER/FAIL | |
539 | */ | |
540 | ||
541 | static int | |
3f7eeb86 | 542 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
543 | { |
544 | uschar *expanded; | |
545 | ||
546 | if (cbinfo->certificate == NULL) | |
547 | return OK; | |
548 | ||
549 | if (Ustrstr(cbinfo->certificate, US"tls_sni")) | |
550 | reexpand_tls_files_for_sni = TRUE; | |
551 | ||
552 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
553 | return DEFER; | |
554 | ||
555 | if (expanded != NULL) | |
556 | { | |
557 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
558 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
559 | return tls_error(string_sprintf( | |
560 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
561 | cbinfo->host, NULL); | |
562 | } | |
563 | ||
564 | if (cbinfo->privatekey != NULL && | |
565 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
566 | return DEFER; | |
567 | ||
568 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
569 | of the expansion is an empty string, ignore it also, and assume the private | |
570 | key is in the same file as the certificate. */ | |
571 | ||
572 | if (expanded != NULL && *expanded != 0) | |
573 | { | |
574 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
575 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
576 | return tls_error(string_sprintf( | |
577 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
578 | } | |
579 | ||
3f7eeb86 PP |
580 | #ifdef EXPERIMENTAL_OCSP |
581 | if (cbinfo->ocsp_file != NULL) | |
582 | { | |
583 | if (!expand_check(cbinfo->ocsp_file, US"tls_ocsp_file", &expanded)) | |
584 | return DEFER; | |
585 | ||
586 | if (expanded != NULL && *expanded != 0) | |
587 | { | |
588 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
589 | if (cbinfo->ocsp_file_expanded && | |
590 | (Ustrcmp(expanded, cbinfo->ocsp_file_expanded) == 0)) | |
591 | { | |
592 | DEBUG(D_tls) | |
593 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
594 | } else { | |
595 | ocsp_load_response(sctx, cbinfo, expanded); | |
596 | } | |
597 | } | |
598 | } | |
599 | #endif | |
600 | ||
7be682ca PP |
601 | return OK; |
602 | } | |
603 | ||
604 | ||
605 | ||
606 | ||
607 | /************************************************* | |
608 | * Callback to handle SNI * | |
609 | *************************************************/ | |
610 | ||
611 | /* Called when acting as server during the TLS session setup if a Server Name | |
612 | Indication extension was sent by the client. | |
613 | ||
614 | API documentation is OpenSSL s_server.c implementation. | |
615 | ||
616 | Arguments: | |
617 | s SSL* of the current session | |
618 | ad unknown (part of OpenSSL API) (unused) | |
619 | arg Callback of "our" registered data | |
620 | ||
621 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
622 | */ | |
623 | ||
3bcbbbe2 | 624 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
625 | static int |
626 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
627 | { | |
628 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 629 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 630 | int rc; |
3f0945ff | 631 | int old_pool = store_pool; |
7be682ca PP |
632 | |
633 | if (!servername) | |
634 | return SSL_TLSEXT_ERR_OK; | |
635 | ||
3f0945ff | 636 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
637 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
638 | ||
639 | /* Make the extension value available for expansion */ | |
3f0945ff | 640 | store_pool = POOL_PERM; |
817d9f57 | 641 | tls_in.sni = string_copy(US servername); |
3f0945ff | 642 | store_pool = old_pool; |
7be682ca PP |
643 | |
644 | if (!reexpand_tls_files_for_sni) | |
645 | return SSL_TLSEXT_ERR_OK; | |
646 | ||
647 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
648 | not confident that memcpy wouldn't break some internal reference counting. | |
649 | Especially since there's a references struct member, which would be off. */ | |
650 | ||
817d9f57 JH |
651 | server_sni = SSL_CTX_new(SSLv23_server_method()); |
652 | if (!server_sni) | |
7be682ca PP |
653 | { |
654 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
655 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
656 | return SSL_TLSEXT_ERR_NOACK; | |
657 | } | |
658 | ||
659 | /* Not sure how many of these are actually needed, since SSL object | |
660 | already exists. Might even need this selfsame callback, for reneg? */ | |
661 | ||
817d9f57 JH |
662 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
663 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
664 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
665 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
666 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
667 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
7be682ca | 668 | if (cbinfo->server_cipher_list) |
817d9f57 | 669 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
3f7eeb86 PP |
670 | #ifdef EXPERIMENTAL_OCSP |
671 | if (cbinfo->ocsp_file) | |
672 | { | |
817d9f57 | 673 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_stapling_cb); |
3f7eeb86 PP |
674 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); |
675 | } | |
676 | #endif | |
7be682ca | 677 | |
a2ff477a | 678 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, FALSE); |
7be682ca PP |
679 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
680 | ||
3f7eeb86 PP |
681 | /* do this after setup_certs, because this can require the certs for verifying |
682 | OCSP information. */ | |
817d9f57 | 683 | rc = tls_expand_session_files(server_sni, cbinfo); |
7be682ca PP |
684 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
685 | ||
a799883d PP |
686 | rc = init_dh(ctx_sni, cbinfo->dhparam, NULL); |
687 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; | |
688 | ||
7be682ca | 689 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 690 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
691 | |
692 | return SSL_TLSEXT_ERR_OK; | |
693 | } | |
3bcbbbe2 | 694 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
695 | |
696 | ||
697 | ||
698 | ||
3f7eeb86 PP |
699 | #ifdef EXPERIMENTAL_OCSP |
700 | /************************************************* | |
701 | * Callback to handle OCSP Stapling * | |
702 | *************************************************/ | |
703 | ||
704 | /* Called when acting as server during the TLS session setup if the client | |
705 | requests OCSP information with a Certificate Status Request. | |
706 | ||
707 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
708 | project. | |
709 | ||
710 | */ | |
711 | ||
712 | static int | |
713 | tls_stapling_cb(SSL *s, void *arg) | |
714 | { | |
715 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
716 | uschar *response_der; | |
717 | int response_der_len; | |
718 | ||
719 | DEBUG(D_tls) debug_printf("Received TLS status request (OCSP stapling); %s response.\n", | |
720 | cbinfo->ocsp_response ? "have" : "lack"); | |
721 | if (!cbinfo->ocsp_response) | |
722 | return SSL_TLSEXT_ERR_NOACK; | |
723 | ||
724 | response_der = NULL; | |
725 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->ocsp_response, &response_der); | |
726 | if (response_der_len <= 0) | |
727 | return SSL_TLSEXT_ERR_NOACK; | |
728 | ||
729 | SSL_set_tlsext_status_ocsp_resp(ssl, response_der, response_der_len); | |
730 | return SSL_TLSEXT_ERR_OK; | |
731 | } | |
732 | ||
733 | #endif /* EXPERIMENTAL_OCSP */ | |
734 | ||
735 | ||
736 | ||
737 | ||
059ec3d9 PH |
738 | /************************************************* |
739 | * Initialize for TLS * | |
740 | *************************************************/ | |
741 | ||
742 | /* Called from both server and client code, to do preliminary initialization of | |
743 | the library. | |
744 | ||
745 | Arguments: | |
746 | host connected host, if client; NULL if server | |
747 | dhparam DH parameter file | |
748 | certificate certificate file | |
749 | privatekey private key | |
750 | addr address if client; NULL if server (for some randomness) | |
751 | ||
752 | Returns: OK/DEFER/FAIL | |
753 | */ | |
754 | ||
755 | static int | |
817d9f57 | 756 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 PP |
757 | uschar *privatekey, |
758 | #ifdef EXPERIMENTAL_OCSP | |
759 | uschar *ocsp_file, | |
760 | #endif | |
817d9f57 | 761 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 762 | { |
77bb000f | 763 | long init_options; |
7be682ca | 764 | int rc; |
77bb000f | 765 | BOOL okay; |
7be682ca PP |
766 | tls_ext_ctx_cb *cbinfo; |
767 | ||
768 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
769 | cbinfo->certificate = certificate; | |
770 | cbinfo->privatekey = privatekey; | |
3f7eeb86 PP |
771 | #ifdef EXPERIMENTAL_OCSP |
772 | cbinfo->ocsp_file = ocsp_file; | |
773 | #endif | |
7be682ca PP |
774 | cbinfo->dhparam = dhparam; |
775 | cbinfo->host = host; | |
77bb000f | 776 | |
059ec3d9 PH |
777 | SSL_load_error_strings(); /* basic set up */ |
778 | OpenSSL_add_ssl_algorithms(); | |
779 | ||
388d6564 | 780 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 781 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
782 | list of available digests. */ |
783 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 784 | #endif |
a0475b69 | 785 | |
f0f5a555 PP |
786 | /* Create a context. |
787 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
788 | negotiation in the different methods; as far as I can tell, the only | |
789 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
790 | when OpenSSL is built without SSLv2 support. | |
791 | By disabling with openssl_options, we can let admins re-enable with the | |
792 | existing knob. */ | |
059ec3d9 | 793 | |
817d9f57 | 794 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
795 | SSLv23_server_method() : SSLv23_client_method()); |
796 | ||
817d9f57 | 797 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
798 | |
799 | /* It turns out that we need to seed the random number generator this early in | |
800 | order to get the full complement of ciphers to work. It took me roughly a day | |
801 | of work to discover this by experiment. | |
802 | ||
803 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
804 | there. Otherwise, we have to make something up as best we can. Double check | |
805 | afterwards. */ | |
806 | ||
807 | if (!RAND_status()) | |
808 | { | |
809 | randstuff r; | |
9e3331ea | 810 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
811 | r.p = getpid(); |
812 | ||
813 | RAND_seed((uschar *)(&r), sizeof(r)); | |
814 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
815 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
816 | ||
817 | if (!RAND_status()) | |
7199e1ee | 818 | return tls_error(US"RAND_status", host, |
5ca6d115 | 819 | US"unable to seed random number generator"); |
059ec3d9 PH |
820 | } |
821 | ||
822 | /* Set up the information callback, which outputs if debugging is at a suitable | |
823 | level. */ | |
824 | ||
817d9f57 | 825 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 826 | |
c80c5570 | 827 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 828 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 829 | |
77bb000f PP |
830 | /* Apply administrator-supplied work-arounds. |
831 | Historically we applied just one requested option, | |
832 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
833 | moved to an administrator-controlled list of options to specify and | |
834 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 835 | |
77bb000f PP |
836 | No OpenSSL version number checks: the options we accept depend upon the |
837 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 838 | |
77bb000f PP |
839 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
840 | if (!okay) | |
73a46702 | 841 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
842 | |
843 | if (init_options) | |
844 | { | |
845 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 846 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
847 | return tls_error(string_sprintf( |
848 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
849 | } | |
850 | else | |
851 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
852 | |
853 | /* Initialize with DH parameters if supplied */ | |
854 | ||
817d9f57 | 855 | <<<<<<< HEAD |
a799883d | 856 | if (!init_dh(ctx, dhparam, host)) return DEFER; |
817d9f57 JH |
857 | ======= |
858 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; | |
859 | >>>>>>> Dual-tls - split management of TLS into in- and out-bound connection-handling. | |
059ec3d9 | 860 | |
3f7eeb86 | 861 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 862 | |
817d9f57 | 863 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 864 | if (rc != OK) return rc; |
c91535f3 | 865 | |
7be682ca | 866 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 867 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f0945ff PP |
868 | if (host == NULL) |
869 | { | |
3f7eeb86 PP |
870 | #ifdef EXPERIMENTAL_OCSP |
871 | /* We check ocsp_file, not ocsp_response, because we care about if | |
872 | the option exists, not what the current expansion might be, as SNI might | |
873 | change the certificate and OCSP file in use between now and the time the | |
874 | callback is invoked. */ | |
875 | if (cbinfo->ocsp_file) | |
876 | { | |
877 | SSL_CTX_set_tlsext_status_cb(ctx, tls_stapling_cb); | |
878 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
879 | } | |
880 | #endif | |
3f0945ff PP |
881 | /* We always do this, so that $tls_sni is available even if not used in |
882 | tls_certificate */ | |
817d9f57 JH |
883 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
884 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 885 | } |
7be682ca | 886 | #endif |
059ec3d9 PH |
887 | |
888 | /* Set up the RSA callback */ | |
889 | ||
817d9f57 | 890 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
891 | |
892 | /* Finally, set the timeout, and we are done */ | |
893 | ||
817d9f57 | 894 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 895 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 896 | |
817d9f57 | 897 | *cbp = cbinfo; |
7be682ca | 898 | |
059ec3d9 PH |
899 | return OK; |
900 | } | |
901 | ||
902 | ||
903 | ||
904 | ||
905 | /************************************************* | |
906 | * Get name of cipher in use * | |
907 | *************************************************/ | |
908 | ||
817d9f57 | 909 | /* |
059ec3d9 | 910 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
911 | buffer to use for answer |
912 | size of buffer | |
913 | pointer to number of bits for cipher | |
059ec3d9 PH |
914 | Returns: nothing |
915 | */ | |
916 | ||
917 | static void | |
817d9f57 | 918 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 919 | { |
57b3a7f5 PP |
920 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
921 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
922 | the accessor functions use const in the prototype. */ | |
923 | const SSL_CIPHER *c; | |
059ec3d9 | 924 | uschar *ver; |
059ec3d9 PH |
925 | |
926 | switch (ssl->session->ssl_version) | |
927 | { | |
928 | case SSL2_VERSION: | |
929 | ver = US"SSLv2"; | |
930 | break; | |
931 | ||
932 | case SSL3_VERSION: | |
933 | ver = US"SSLv3"; | |
934 | break; | |
935 | ||
936 | case TLS1_VERSION: | |
937 | ver = US"TLSv1"; | |
938 | break; | |
939 | ||
c80c5570 PP |
940 | #ifdef TLS1_1_VERSION |
941 | case TLS1_1_VERSION: | |
942 | ver = US"TLSv1.1"; | |
943 | break; | |
944 | #endif | |
945 | ||
946 | #ifdef TLS1_2_VERSION | |
947 | case TLS1_2_VERSION: | |
948 | ver = US"TLSv1.2"; | |
949 | break; | |
950 | #endif | |
951 | ||
059ec3d9 PH |
952 | default: |
953 | ver = US"UNKNOWN"; | |
954 | } | |
955 | ||
57b3a7f5 | 956 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 957 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 958 | |
817d9f57 JH |
959 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
960 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
961 | |
962 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
963 | } | |
964 | ||
965 | ||
966 | ||
967 | ||
968 | ||
969 | /************************************************* | |
970 | * Set up for verifying certificates * | |
971 | *************************************************/ | |
972 | ||
973 | /* Called by both client and server startup | |
974 | ||
975 | Arguments: | |
7be682ca | 976 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
977 | certs certs file or NULL |
978 | crl CRL file or NULL | |
979 | host NULL in a server; the remote host in a client | |
980 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
981 | otherwise passed as FALSE | |
a2ff477a | 982 | client TRUE if called for client startup, FALSE for server startup |
059ec3d9 PH |
983 | |
984 | Returns: OK/DEFER/FAIL | |
985 | */ | |
986 | ||
987 | static int | |
a2ff477a | 988 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, BOOL client) |
059ec3d9 PH |
989 | { |
990 | uschar *expcerts, *expcrl; | |
991 | ||
992 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
993 | return DEFER; | |
994 | ||
995 | if (expcerts != NULL) | |
996 | { | |
997 | struct stat statbuf; | |
7be682ca | 998 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
7199e1ee | 999 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
1000 | |
1001 | if (Ustat(expcerts, &statbuf) < 0) | |
1002 | { | |
1003 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1004 | "failed to stat %s for certificates", expcerts); | |
1005 | return DEFER; | |
1006 | } | |
1007 | else | |
1008 | { | |
1009 | uschar *file, *dir; | |
1010 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1011 | { file = NULL; dir = expcerts; } | |
1012 | else | |
1013 | { file = expcerts; dir = NULL; } | |
1014 | ||
1015 | /* If a certificate file is empty, the next function fails with an | |
1016 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1017 | certificates are recognized, but the error message is still misleading (it | |
1018 | says no certificate was supplied.) But this is better. */ | |
1019 | ||
1020 | if ((file == NULL || statbuf.st_size > 0) && | |
7be682ca | 1021 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) |
7199e1ee | 1022 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 PH |
1023 | |
1024 | if (file != NULL) | |
1025 | { | |
7be682ca | 1026 | SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); |
059ec3d9 PH |
1027 | } |
1028 | } | |
1029 | ||
1030 | /* Handle a certificate revocation list. */ | |
1031 | ||
1032 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1033 | ||
8b417f2c PH |
1034 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1035 | * merely reformatted it into the Exim code style.) | |
1036 | ||
1037 | * "From here I changed the code to add support for multiple crl's | |
1038 | * in pem format in one file or to support hashed directory entries in | |
1039 | * pem format instead of a file. This method now uses the library function | |
1040 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1041 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1042 | * itself in the verify callback." */ | |
1043 | ||
059ec3d9 PH |
1044 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1045 | if (expcrl != NULL && *expcrl != 0) | |
1046 | { | |
8b417f2c PH |
1047 | struct stat statbufcrl; |
1048 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1049 | { | |
1050 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1051 | "failed to stat %s for certificates revocation lists", expcrl); | |
1052 | return DEFER; | |
1053 | } | |
1054 | else | |
059ec3d9 | 1055 | { |
8b417f2c PH |
1056 | /* is it a file or directory? */ |
1057 | uschar *file, *dir; | |
7be682ca | 1058 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1059 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1060 | { |
8b417f2c PH |
1061 | file = NULL; |
1062 | dir = expcrl; | |
1063 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1064 | } |
1065 | else | |
1066 | { | |
8b417f2c PH |
1067 | file = expcrl; |
1068 | dir = NULL; | |
1069 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1070 | } |
8b417f2c | 1071 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1072 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1073 | |
1074 | /* setting the flags to check against the complete crl chain */ | |
1075 | ||
1076 | X509_STORE_set_flags(cvstore, | |
1077 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1078 | } |
059ec3d9 PH |
1079 | } |
1080 | ||
1081 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1082 | ||
1083 | /* If verification is optional, don't fail if no certificate */ | |
1084 | ||
7be682ca | 1085 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1086 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
a2ff477a | 1087 | client ? verify_callback_client : verify_callback_server); |
059ec3d9 PH |
1088 | } |
1089 | ||
1090 | return OK; | |
1091 | } | |
1092 | ||
1093 | ||
1094 | ||
1095 | /************************************************* | |
1096 | * Start a TLS session in a server * | |
1097 | *************************************************/ | |
1098 | ||
1099 | /* This is called when Exim is running as a server, after having received | |
1100 | the STARTTLS command. It must respond to that command, and then negotiate | |
1101 | a TLS session. | |
1102 | ||
1103 | Arguments: | |
1104 | require_ciphers allowed ciphers | |
1105 | ||
1106 | Returns: OK on success | |
1107 | DEFER for errors before the start of the negotiation | |
1108 | FAIL for errors during the negotation; the server can't | |
1109 | continue running. | |
1110 | */ | |
1111 | ||
1112 | int | |
17c76198 | 1113 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1114 | { |
1115 | int rc; | |
1116 | uschar *expciphers; | |
7be682ca | 1117 | tls_ext_ctx_cb *cbinfo; |
817d9f57 | 1118 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1119 | |
1120 | /* Check for previous activation */ | |
1121 | ||
817d9f57 | 1122 | if (tls_in.active >= 0) |
059ec3d9 | 1123 | { |
5ca6d115 | 1124 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1125 | smtp_printf("554 Already in TLS\r\n"); |
1126 | return FAIL; | |
1127 | } | |
1128 | ||
1129 | /* Initialize the SSL library. If it fails, it will already have logged | |
1130 | the error. */ | |
1131 | ||
817d9f57 | 1132 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
3f7eeb86 PP |
1133 | #ifdef EXPERIMENTAL_OCSP |
1134 | tls_ocsp_file, | |
1135 | #endif | |
817d9f57 | 1136 | NULL, &server_static_cbinfo); |
059ec3d9 | 1137 | if (rc != OK) return rc; |
817d9f57 | 1138 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1139 | |
1140 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1141 | return FAIL; | |
1142 | ||
1143 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1144 | were historically separated by underscores. So that I can use either form in my |
1145 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1146 | */ | |
059ec3d9 PH |
1147 | |
1148 | if (expciphers != NULL) | |
1149 | { | |
1150 | uschar *s = expciphers; | |
1151 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1152 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1153 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1154 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1155 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1156 | } |
1157 | ||
1158 | /* If this is a host for which certificate verification is mandatory or | |
1159 | optional, set up appropriately. */ | |
1160 | ||
817d9f57 | 1161 | tls_in.certificate_verified = FALSE; |
a2ff477a | 1162 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1163 | |
1164 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1165 | { | |
a2ff477a | 1166 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, FALSE, FALSE); |
059ec3d9 | 1167 | if (rc != OK) return rc; |
a2ff477a | 1168 | server_verify_optional = FALSE; |
059ec3d9 PH |
1169 | } |
1170 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1171 | { | |
a2ff477a | 1172 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, TRUE, FALSE); |
059ec3d9 | 1173 | if (rc != OK) return rc; |
a2ff477a | 1174 | server_verify_optional = TRUE; |
059ec3d9 PH |
1175 | } |
1176 | ||
1177 | /* Prepare for new connection */ | |
1178 | ||
817d9f57 | 1179 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1180 | |
1181 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1182 | * | |
1183 | * With the SSL_clear(), we get strange interoperability bugs with | |
1184 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1185 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1186 | * | |
1187 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1188 | * session shutdown. In this case, we have a brand new object and there's no | |
1189 | * obvious reason to immediately clear it. I'm guessing that this was | |
1190 | * originally added because of incomplete initialisation which the clear fixed, | |
1191 | * in some historic release. | |
1192 | */ | |
059ec3d9 PH |
1193 | |
1194 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1195 | on connection, where outputting anything now upsets the clients and tends to | |
1196 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1197 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1198 | mode, the fflush() happens when smtp_getc() is called. */ | |
1199 | ||
817d9f57 JH |
1200 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1201 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1202 | { |
1203 | smtp_printf("220 TLS go ahead\r\n"); | |
1204 | fflush(smtp_out); | |
1205 | } | |
1206 | ||
1207 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1208 | that the OpenSSL library doesn't. */ | |
1209 | ||
817d9f57 JH |
1210 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1211 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1212 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1213 | |
1214 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1215 | ||
1216 | sigalrm_seen = FALSE; | |
1217 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1218 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1219 | alarm(0); |
1220 | ||
1221 | if (rc <= 0) | |
1222 | { | |
7199e1ee | 1223 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1224 | if (ERR_get_error() == 0) |
1225 | log_write(0, LOG_MAIN, | |
a053d125 | 1226 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1227 | return FAIL; |
1228 | } | |
1229 | ||
1230 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1231 | ||
1232 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1233 | and initialize things. */ | |
1234 | ||
817d9f57 JH |
1235 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1236 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1237 | |
1238 | DEBUG(D_tls) | |
1239 | { | |
1240 | uschar buf[2048]; | |
817d9f57 | 1241 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1242 | debug_printf("Shared ciphers: %s\n", buf); |
1243 | } | |
1244 | ||
1245 | ||
817d9f57 JH |
1246 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1247 | Client-side (tls_out) reads (seem to?) go via | |
1248 | smtp_read_response()/ip_recv(). | |
1249 | Hence no need to duplicate for _in and _out. | |
1250 | */ | |
059ec3d9 PH |
1251 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1252 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1253 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1254 | ||
1255 | receive_getc = tls_getc; | |
1256 | receive_ungetc = tls_ungetc; | |
1257 | receive_feof = tls_feof; | |
1258 | receive_ferror = tls_ferror; | |
58eb016e | 1259 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1260 | |
817d9f57 | 1261 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1262 | return OK; |
1263 | } | |
1264 | ||
1265 | ||
1266 | ||
1267 | ||
1268 | ||
1269 | /************************************************* | |
1270 | * Start a TLS session in a client * | |
1271 | *************************************************/ | |
1272 | ||
1273 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1274 | ||
1275 | Argument: | |
1276 | fd the fd of the connection | |
1277 | host connected host (for messages) | |
83da1223 | 1278 | addr the first address |
059ec3d9 PH |
1279 | dhparam DH parameter file |
1280 | certificate certificate file | |
1281 | privatekey private key file | |
3f0945ff | 1282 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1283 | verify_certs file for certificate verify |
1284 | crl file containing CRL | |
1285 | require_ciphers list of allowed ciphers | |
54c90be1 PP |
1286 | dh_min_bits minimum number of bits acceptable in server's DH prime |
1287 | (unused in OpenSSL) | |
83da1223 | 1288 | timeout startup timeout |
059ec3d9 PH |
1289 | |
1290 | Returns: OK on success | |
1291 | FAIL otherwise - note that tls_error() will not give DEFER | |
1292 | because this is not a server | |
1293 | */ | |
1294 | ||
1295 | int | |
1296 | tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, | |
3f0945ff PP |
1297 | uschar *certificate, uschar *privatekey, uschar *sni, |
1298 | uschar *verify_certs, uschar *crl, | |
54c90be1 | 1299 | uschar *require_ciphers, int dh_min_bits ARG_UNUSED, int timeout) |
059ec3d9 PH |
1300 | { |
1301 | static uschar txt[256]; | |
1302 | uschar *expciphers; | |
1303 | X509* server_cert; | |
1304 | int rc; | |
817d9f57 | 1305 | static uschar cipherbuf[256]; |
059ec3d9 | 1306 | |
817d9f57 | 1307 | rc = tls_init(&client_ctx, host, dhparam, certificate, privatekey, |
3f7eeb86 PP |
1308 | #ifdef EXPERIMENTAL_OCSP |
1309 | NULL, | |
1310 | #endif | |
817d9f57 | 1311 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1312 | if (rc != OK) return rc; |
1313 | ||
817d9f57 | 1314 | tls_out.certificate_verified = FALSE; |
a2ff477a | 1315 | client_verify_callback_called = FALSE; |
059ec3d9 PH |
1316 | |
1317 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1318 | return FAIL; | |
1319 | ||
1320 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1321 | are separated by underscores. So that I can use either form in my tests, and | |
1322 | also for general convenience, we turn underscores into hyphens here. */ | |
1323 | ||
1324 | if (expciphers != NULL) | |
1325 | { | |
1326 | uschar *s = expciphers; | |
1327 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1328 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1329 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1330 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1331 | } |
1332 | ||
a2ff477a | 1333 | rc = setup_certs(client_ctx, verify_certs, crl, host, FALSE, TRUE); |
059ec3d9 PH |
1334 | if (rc != OK) return rc; |
1335 | ||
817d9f57 JH |
1336 | if ((client_ssl = SSL_new(client_ctx)) == NULL) return tls_error(US"SSL_new", host, NULL); |
1337 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); | |
1338 | SSL_set_fd(client_ssl, fd); | |
1339 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 1340 | |
3f0945ff PP |
1341 | if (sni) |
1342 | { | |
817d9f57 | 1343 | if (!expand_check(sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 1344 | return FAIL; |
817d9f57 JH |
1345 | if (!Ustrlen(tls_out.sni)) |
1346 | tls_out.sni = NULL; | |
3f0945ff PP |
1347 | else |
1348 | { | |
35731706 | 1349 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
1350 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
1351 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
1352 | #else |
1353 | DEBUG(D_tls) | |
1354 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
1355 | tls_sni); | |
1356 | #endif | |
3f0945ff PP |
1357 | } |
1358 | } | |
1359 | ||
059ec3d9 PH |
1360 | /* There doesn't seem to be a built-in timeout on connection. */ |
1361 | ||
1362 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1363 | sigalrm_seen = FALSE; | |
1364 | alarm(timeout); | |
817d9f57 | 1365 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
1366 | alarm(0); |
1367 | ||
1368 | if (rc <= 0) | |
7199e1ee | 1369 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1370 | |
1371 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1372 | ||
453a6645 | 1373 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
817d9f57 | 1374 | server_cert = SSL_get_peer_certificate (client_ssl); |
453a6645 PP |
1375 | if (server_cert) |
1376 | { | |
817d9f57 | 1377 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), |
453a6645 | 1378 | CS txt, sizeof(txt)); |
817d9f57 | 1379 | tls_out.peerdn = txt; |
453a6645 PP |
1380 | } |
1381 | else | |
817d9f57 | 1382 | tls_out.peerdn = NULL; |
059ec3d9 | 1383 | |
817d9f57 JH |
1384 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
1385 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 1386 | |
817d9f57 | 1387 | tls_out.active = fd; |
059ec3d9 PH |
1388 | return OK; |
1389 | } | |
1390 | ||
1391 | ||
1392 | ||
1393 | ||
1394 | ||
1395 | /************************************************* | |
1396 | * TLS version of getc * | |
1397 | *************************************************/ | |
1398 | ||
1399 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1400 | it refills the buffer via the SSL reading function. | |
1401 | ||
1402 | Arguments: none | |
1403 | Returns: the next character or EOF | |
817d9f57 JH |
1404 | |
1405 | Only used by the server-side TLS. | |
059ec3d9 PH |
1406 | */ |
1407 | ||
1408 | int | |
1409 | tls_getc(void) | |
1410 | { | |
1411 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1412 | { | |
1413 | int error; | |
1414 | int inbytes; | |
1415 | ||
817d9f57 | 1416 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 1417 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
1418 | |
1419 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
1420 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
1421 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
1422 | alarm(0); |
1423 | ||
1424 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
1425 | closed down, not that the socket itself has been closed down. Revert to | |
1426 | non-SSL handling. */ | |
1427 | ||
1428 | if (error == SSL_ERROR_ZERO_RETURN) | |
1429 | { | |
1430 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1431 | ||
1432 | receive_getc = smtp_getc; | |
1433 | receive_ungetc = smtp_ungetc; | |
1434 | receive_feof = smtp_feof; | |
1435 | receive_ferror = smtp_ferror; | |
58eb016e | 1436 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1437 | |
817d9f57 JH |
1438 | SSL_free(server_ssl); |
1439 | server_ssl = NULL; | |
1440 | tls_in.active = -1; | |
1441 | tls_in.bits = 0; | |
1442 | tls_in.cipher = NULL; | |
1443 | tls_in.peerdn = NULL; | |
1444 | tls_in.sni = NULL; | |
059ec3d9 PH |
1445 | |
1446 | return smtp_getc(); | |
1447 | } | |
1448 | ||
1449 | /* Handle genuine errors */ | |
1450 | ||
ba084640 PP |
1451 | else if (error == SSL_ERROR_SSL) |
1452 | { | |
1453 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 1454 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
1455 | ssl_xfer_error = 1; |
1456 | return EOF; | |
1457 | } | |
1458 | ||
059ec3d9 PH |
1459 | else if (error != SSL_ERROR_NONE) |
1460 | { | |
1461 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
1462 | ssl_xfer_error = 1; | |
1463 | return EOF; | |
1464 | } | |
c80c5570 | 1465 | |
80a47a2c TK |
1466 | #ifndef DISABLE_DKIM |
1467 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
1468 | #endif | |
059ec3d9 PH |
1469 | ssl_xfer_buffer_hwm = inbytes; |
1470 | ssl_xfer_buffer_lwm = 0; | |
1471 | } | |
1472 | ||
1473 | /* Something in the buffer; return next uschar */ | |
1474 | ||
1475 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1476 | } | |
1477 | ||
1478 | ||
1479 | ||
1480 | /************************************************* | |
1481 | * Read bytes from TLS channel * | |
1482 | *************************************************/ | |
1483 | ||
1484 | /* | |
1485 | Arguments: | |
1486 | buff buffer of data | |
1487 | len size of buffer | |
1488 | ||
1489 | Returns: the number of bytes read | |
1490 | -1 after a failed read | |
817d9f57 JH |
1491 | |
1492 | Only used by the client-side TLS. | |
059ec3d9 PH |
1493 | */ |
1494 | ||
1495 | int | |
1496 | tls_read(uschar *buff, size_t len) | |
1497 | { | |
1498 | int inbytes; | |
1499 | int error; | |
1500 | ||
817d9f57 | 1501 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", client_ssl, |
c80c5570 | 1502 | buff, (unsigned int)len); |
059ec3d9 | 1503 | |
817d9f57 JH |
1504 | inbytes = SSL_read(client_ssl, CS buff, len); |
1505 | error = SSL_get_error(client_ssl, inbytes); | |
059ec3d9 PH |
1506 | |
1507 | if (error == SSL_ERROR_ZERO_RETURN) | |
1508 | { | |
1509 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1510 | return -1; | |
1511 | } | |
1512 | else if (error != SSL_ERROR_NONE) | |
1513 | { | |
1514 | return -1; | |
1515 | } | |
1516 | ||
1517 | return inbytes; | |
1518 | } | |
1519 | ||
1520 | ||
1521 | ||
1522 | ||
1523 | ||
1524 | /************************************************* | |
1525 | * Write bytes down TLS channel * | |
1526 | *************************************************/ | |
1527 | ||
1528 | /* | |
1529 | Arguments: | |
817d9f57 | 1530 | is_server channel specifier |
059ec3d9 PH |
1531 | buff buffer of data |
1532 | len number of bytes | |
1533 | ||
1534 | Returns: the number of bytes after a successful write, | |
1535 | -1 after a failed write | |
817d9f57 JH |
1536 | |
1537 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1538 | */ |
1539 | ||
1540 | int | |
817d9f57 | 1541 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
1542 | { |
1543 | int outbytes; | |
1544 | int error; | |
1545 | int left = len; | |
817d9f57 | 1546 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 1547 | |
c80c5570 | 1548 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
1549 | while (left > 0) |
1550 | { | |
c80c5570 | 1551 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
1552 | outbytes = SSL_write(ssl, CS buff, left); |
1553 | error = SSL_get_error(ssl, outbytes); | |
1554 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1555 | switch (error) | |
1556 | { | |
1557 | case SSL_ERROR_SSL: | |
1558 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1559 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1560 | return -1; | |
1561 | ||
1562 | case SSL_ERROR_NONE: | |
1563 | left -= outbytes; | |
1564 | buff += outbytes; | |
1565 | break; | |
1566 | ||
1567 | case SSL_ERROR_ZERO_RETURN: | |
1568 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1569 | return -1; | |
1570 | ||
817d9f57 JH |
1571 | case SSL_ERROR_SYSCALL: |
1572 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
1573 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
1574 | strerror(errno)); | |
1575 | ||
059ec3d9 PH |
1576 | default: |
1577 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1578 | return -1; | |
1579 | } | |
1580 | } | |
1581 | return len; | |
1582 | } | |
1583 | ||
1584 | ||
1585 | ||
1586 | /************************************************* | |
1587 | * Close down a TLS session * | |
1588 | *************************************************/ | |
1589 | ||
1590 | /* This is also called from within a delivery subprocess forked from the | |
1591 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1592 | would tamper with the SSL session in the parent process). | |
1593 | ||
1594 | Arguments: TRUE if SSL_shutdown is to be called | |
1595 | Returns: nothing | |
817d9f57 JH |
1596 | |
1597 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1598 | */ |
1599 | ||
1600 | void | |
817d9f57 | 1601 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1602 | { |
817d9f57 JH |
1603 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
1604 | ||
1605 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
1606 | |
1607 | if (shutdown) | |
1608 | { | |
1609 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 1610 | SSL_shutdown(*sslp); |
059ec3d9 PH |
1611 | } |
1612 | ||
817d9f57 JH |
1613 | SSL_free(*sslp); |
1614 | *sslp = NULL; | |
059ec3d9 | 1615 | |
817d9f57 | 1616 | *fdp = -1; |
059ec3d9 PH |
1617 | } |
1618 | ||
36f12725 NM |
1619 | |
1620 | ||
1621 | ||
3375e053 PP |
1622 | /************************************************* |
1623 | * Let tls_require_ciphers be checked at startup * | |
1624 | *************************************************/ | |
1625 | ||
1626 | /* The tls_require_ciphers option, if set, must be something which the | |
1627 | library can parse. | |
1628 | ||
1629 | Returns: NULL on success, or error message | |
1630 | */ | |
1631 | ||
1632 | uschar * | |
1633 | tls_validate_require_cipher(void) | |
1634 | { | |
1635 | SSL_CTX *ctx; | |
1636 | uschar *s, *expciphers, *err; | |
1637 | ||
1638 | /* this duplicates from tls_init(), we need a better "init just global | |
1639 | state, for no specific purpose" singleton function of our own */ | |
1640 | ||
1641 | SSL_load_error_strings(); | |
1642 | OpenSSL_add_ssl_algorithms(); | |
1643 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
1644 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
1645 | list of available digests. */ | |
1646 | EVP_add_digest(EVP_sha256()); | |
1647 | #endif | |
1648 | ||
1649 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1650 | return NULL; | |
1651 | ||
1652 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1653 | return US"failed to expand tls_require_ciphers"; | |
1654 | ||
1655 | if (!(expciphers && *expciphers)) | |
1656 | return NULL; | |
1657 | ||
1658 | /* normalisation ripped from above */ | |
1659 | s = expciphers; | |
1660 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1661 | ||
1662 | err = NULL; | |
1663 | ||
1664 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
1665 | if (!ctx) | |
1666 | { | |
1667 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1668 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
1669 | } | |
1670 | ||
1671 | DEBUG(D_tls) | |
1672 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1673 | ||
1674 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
1675 | { | |
1676 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1677 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
1678 | } | |
1679 | ||
1680 | SSL_CTX_free(ctx); | |
1681 | ||
1682 | return err; | |
1683 | } | |
1684 | ||
1685 | ||
1686 | ||
1687 | ||
36f12725 NM |
1688 | /************************************************* |
1689 | * Report the library versions. * | |
1690 | *************************************************/ | |
1691 | ||
1692 | /* There have historically been some issues with binary compatibility in | |
1693 | OpenSSL libraries; if Exim (like many other applications) is built against | |
1694 | one version of OpenSSL but the run-time linker picks up another version, | |
1695 | it can result in serious failures, including crashing with a SIGSEGV. So | |
1696 | report the version found by the compiler and the run-time version. | |
1697 | ||
1698 | Arguments: a FILE* to print the results to | |
1699 | Returns: nothing | |
1700 | */ | |
1701 | ||
1702 | void | |
1703 | tls_version_report(FILE *f) | |
1704 | { | |
754a0503 PP |
1705 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
1706 | " Runtime: %s\n", | |
1707 | OPENSSL_VERSION_TEXT, | |
1708 | SSLeay_version(SSLEAY_VERSION)); | |
36f12725 NM |
1709 | } |
1710 | ||
9e3331ea TK |
1711 | |
1712 | ||
1713 | ||
1714 | /************************************************* | |
17c76198 | 1715 | * Random number generation * |
9e3331ea TK |
1716 | *************************************************/ |
1717 | ||
1718 | /* Pseudo-random number generation. The result is not expected to be | |
1719 | cryptographically strong but not so weak that someone will shoot themselves | |
1720 | in the foot using it as a nonce in input in some email header scheme or | |
1721 | whatever weirdness they'll twist this into. The result should handle fork() | |
1722 | and avoid repeating sequences. OpenSSL handles that for us. | |
1723 | ||
1724 | Arguments: | |
1725 | max range maximum | |
1726 | Returns a random number in range [0, max-1] | |
1727 | */ | |
1728 | ||
1729 | int | |
17c76198 | 1730 | vaguely_random_number(int max) |
9e3331ea TK |
1731 | { |
1732 | unsigned int r; | |
1733 | int i, needed_len; | |
1734 | uschar *p; | |
1735 | uschar smallbuf[sizeof(r)]; | |
1736 | ||
1737 | if (max <= 1) | |
1738 | return 0; | |
1739 | ||
1740 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ | |
1741 | if (!RAND_status()) | |
1742 | { | |
1743 | randstuff r; | |
1744 | gettimeofday(&r.tv, NULL); | |
1745 | r.p = getpid(); | |
1746 | ||
1747 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1748 | } | |
1749 | /* We're after pseudo-random, not random; if we still don't have enough data | |
1750 | in the internal PRNG then our options are limited. We could sleep and hope | |
1751 | for entropy to come along (prayer technique) but if the system is so depleted | |
1752 | in the first place then something is likely to just keep taking it. Instead, | |
1753 | we'll just take whatever little bit of pseudo-random we can still manage to | |
1754 | get. */ | |
1755 | ||
1756 | needed_len = sizeof(r); | |
1757 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1758 | asked for a number less than 10. */ | |
1759 | for (r = max, i = 0; r; ++i) | |
1760 | r >>= 1; | |
1761 | i = (i + 7) / 8; | |
1762 | if (i < needed_len) | |
1763 | needed_len = i; | |
1764 | ||
1765 | /* We do not care if crypto-strong */ | |
17c76198 PP |
1766 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
1767 | if (i < 0) | |
1768 | { | |
1769 | DEBUG(D_all) | |
1770 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
1771 | return vaguely_random_number_fallback(max); | |
1772 | } | |
1773 | ||
9e3331ea TK |
1774 | r = 0; |
1775 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
1776 | { | |
1777 | r *= 256; | |
1778 | r += *p; | |
1779 | } | |
1780 | ||
1781 | /* We don't particularly care about weighted results; if someone wants | |
1782 | smooth distribution and cares enough then they should submit a patch then. */ | |
1783 | return r % max; | |
1784 | } | |
1785 | ||
77bb000f PP |
1786 | |
1787 | ||
1788 | ||
1789 | /************************************************* | |
1790 | * OpenSSL option parse * | |
1791 | *************************************************/ | |
1792 | ||
1793 | /* Parse one option for tls_openssl_options_parse below | |
1794 | ||
1795 | Arguments: | |
1796 | name one option name | |
1797 | value place to store a value for it | |
1798 | Returns success or failure in parsing | |
1799 | */ | |
1800 | ||
1801 | struct exim_openssl_option { | |
1802 | uschar *name; | |
1803 | long value; | |
1804 | }; | |
1805 | /* We could use a macro to expand, but we need the ifdef and not all the | |
1806 | options document which version they were introduced in. Policylet: include | |
1807 | all options unless explicitly for DTLS, let the administrator choose which | |
1808 | to apply. | |
1809 | ||
1810 | This list is current as of: | |
c80c5570 | 1811 | ==> 1.0.1b <== */ |
77bb000f PP |
1812 | static struct exim_openssl_option exim_openssl_options[] = { |
1813 | /* KEEP SORTED ALPHABETICALLY! */ | |
1814 | #ifdef SSL_OP_ALL | |
73a46702 | 1815 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
1816 | #endif |
1817 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 1818 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
1819 | #endif |
1820 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 1821 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
1822 | #endif |
1823 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 1824 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
1825 | #endif |
1826 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 1827 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
1828 | #endif |
1829 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 1830 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
1831 | #endif |
1832 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 1833 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
1834 | #endif |
1835 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 1836 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
1837 | #endif |
1838 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 1839 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
1840 | #endif |
1841 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 1842 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
1843 | #endif |
1844 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 1845 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 1846 | #endif |
c80c5570 PP |
1847 | #ifdef SSL_OP_NO_COMPRESSION |
1848 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
1849 | #endif | |
77bb000f | 1850 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 1851 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 1852 | #endif |
c0c7b2da PP |
1853 | #ifdef SSL_OP_NO_SSLv2 |
1854 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
1855 | #endif | |
1856 | #ifdef SSL_OP_NO_SSLv3 | |
1857 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
1858 | #endif | |
1859 | #ifdef SSL_OP_NO_TICKET | |
1860 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
1861 | #endif | |
1862 | #ifdef SSL_OP_NO_TLSv1 | |
1863 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
1864 | #endif | |
c80c5570 PP |
1865 | #ifdef SSL_OP_NO_TLSv1_1 |
1866 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
1867 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
1868 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
1869 | #else | |
1870 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
1871 | #endif | |
1872 | #endif | |
1873 | #ifdef SSL_OP_NO_TLSv1_2 | |
1874 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
1875 | #endif | |
77bb000f | 1876 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 1877 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
1878 | #endif |
1879 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 1880 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
1881 | #endif |
1882 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 1883 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
1884 | #endif |
1885 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 1886 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
1887 | #endif |
1888 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 1889 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
1890 | #endif |
1891 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 1892 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
1893 | #endif |
1894 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 1895 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
1896 | #endif |
1897 | }; | |
1898 | static int exim_openssl_options_size = | |
1899 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
1900 | ||
c80c5570 | 1901 | |
77bb000f PP |
1902 | static BOOL |
1903 | tls_openssl_one_option_parse(uschar *name, long *value) | |
1904 | { | |
1905 | int first = 0; | |
1906 | int last = exim_openssl_options_size; | |
1907 | while (last > first) | |
1908 | { | |
1909 | int middle = (first + last)/2; | |
1910 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
1911 | if (c == 0) | |
1912 | { | |
1913 | *value = exim_openssl_options[middle].value; | |
1914 | return TRUE; | |
1915 | } | |
1916 | else if (c > 0) | |
1917 | first = middle + 1; | |
1918 | else | |
1919 | last = middle; | |
1920 | } | |
1921 | return FALSE; | |
1922 | } | |
1923 | ||
1924 | ||
1925 | ||
1926 | ||
1927 | /************************************************* | |
1928 | * OpenSSL option parsing logic * | |
1929 | *************************************************/ | |
1930 | ||
1931 | /* OpenSSL has a number of compatibility options which an administrator might | |
1932 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
1933 | we look like log_selector. | |
1934 | ||
1935 | Arguments: | |
1936 | option_spec the administrator-supplied string of options | |
1937 | results ptr to long storage for the options bitmap | |
1938 | Returns success or failure | |
1939 | */ | |
1940 | ||
1941 | BOOL | |
1942 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
1943 | { | |
1944 | long result, item; | |
1945 | uschar *s, *end; | |
1946 | uschar keep_c; | |
1947 | BOOL adding, item_parsed; | |
1948 | ||
0e944a0d | 1949 | result = 0L; |
b1770b6e | 1950 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 1951 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
1952 | #ifdef SSL_OP_NO_SSLv2 |
1953 | result |= SSL_OP_NO_SSLv2; | |
1954 | #endif | |
77bb000f PP |
1955 | |
1956 | if (option_spec == NULL) | |
1957 | { | |
1958 | *results = result; | |
1959 | return TRUE; | |
1960 | } | |
1961 | ||
1962 | for (s=option_spec; *s != '\0'; /**/) | |
1963 | { | |
1964 | while (isspace(*s)) ++s; | |
1965 | if (*s == '\0') | |
1966 | break; | |
1967 | if (*s != '+' && *s != '-') | |
1968 | { | |
1969 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 1970 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
1971 | return FALSE; |
1972 | } | |
1973 | adding = *s++ == '+'; | |
1974 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
1975 | keep_c = *end; | |
1976 | *end = '\0'; | |
1977 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
1978 | if (!item_parsed) | |
1979 | { | |
0e944a0d | 1980 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
1981 | return FALSE; |
1982 | } | |
1983 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
1984 | adding ? "adding" : "removing", result, item, s); | |
1985 | if (adding) | |
1986 | result |= item; | |
1987 | else | |
1988 | result &= ~item; | |
1989 | *end = keep_c; | |
1990 | s = end; | |
1991 | } | |
1992 | ||
1993 | *results = result; | |
1994 | return TRUE; | |
1995 | } | |
1996 | ||
059ec3d9 | 1997 | /* End of tls-openssl.c */ |