Commit | Line | Data |
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059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
5a66c31b | 5 | /* Copyright (c) University of Cambridge 1995 - 2014 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
f5d78688 JH |
8 | /* Portions Copyright (c) The OpenSSL Project 1999 */ |
9 | ||
059ec3d9 PH |
10 | /* This module provides the TLS (aka SSL) support for Exim using the OpenSSL |
11 | library. It is #included into the tls.c file when that library is used. The | |
12 | code herein is based on a patch that was originally contributed by Steve | |
13 | Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara. | |
14 | ||
15 | No cryptographic code is included in Exim. All this module does is to call | |
16 | functions from the OpenSSL library. */ | |
17 | ||
18 | ||
19 | /* Heading stuff */ | |
20 | ||
21 | #include <openssl/lhash.h> | |
22 | #include <openssl/ssl.h> | |
23 | #include <openssl/err.h> | |
24 | #include <openssl/rand.h> | |
f2de3a33 | 25 | #ifndef DISABLE_OCSP |
e51c7be2 | 26 | # include <openssl/ocsp.h> |
3f7eeb86 PP |
27 | #endif |
28 | ||
f2de3a33 JH |
29 | #ifndef DISABLE_OCSP |
30 | # define EXIM_OCSP_SKEW_SECONDS (300L) | |
31 | # define EXIM_OCSP_MAX_AGE (-1L) | |
3f7eeb86 | 32 | #endif |
059ec3d9 | 33 | |
3bcbbbe2 | 34 | #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) |
e51c7be2 | 35 | # define EXIM_HAVE_OPENSSL_TLSEXT |
3bcbbbe2 PP |
36 | #endif |
37 | ||
059ec3d9 PH |
38 | /* Structure for collecting random data for seeding. */ |
39 | ||
40 | typedef struct randstuff { | |
9e3331ea TK |
41 | struct timeval tv; |
42 | pid_t p; | |
059ec3d9 PH |
43 | } randstuff; |
44 | ||
45 | /* Local static variables */ | |
46 | ||
a2ff477a JH |
47 | static BOOL client_verify_callback_called = FALSE; |
48 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
49 | static const uschar *sid_ctx = US"exim"; |
50 | ||
d4f09789 PP |
51 | /* We have three different contexts to care about. |
52 | ||
53 | Simple case: client, `client_ctx` | |
54 | As a client, we can be doing a callout or cut-through delivery while receiving | |
55 | a message. So we have a client context, which should have options initialised | |
56 | from the SMTP Transport. | |
57 | ||
58 | Server: | |
59 | There are two cases: with and without ServerNameIndication from the client. | |
60 | Given TLS SNI, we can be using different keys, certs and various other | |
61 | configuration settings, because they're re-expanded with $tls_sni set. This | |
62 | allows vhosting with TLS. This SNI is sent in the handshake. | |
63 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
64 | So as a server, we start out using `server_ctx`. | |
65 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
66 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
67 | configuration. | |
68 | */ | |
69 | ||
817d9f57 JH |
70 | static SSL_CTX *client_ctx = NULL; |
71 | static SSL_CTX *server_ctx = NULL; | |
72 | static SSL *client_ssl = NULL; | |
73 | static SSL *server_ssl = NULL; | |
389ca47a | 74 | |
35731706 | 75 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 76 | static SSL_CTX *server_sni = NULL; |
35731706 | 77 | #endif |
059ec3d9 PH |
78 | |
79 | static char ssl_errstring[256]; | |
80 | ||
81 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
82 | static BOOL client_verify_optional = FALSE; |
83 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 84 | |
f5d78688 | 85 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
86 | |
87 | ||
7be682ca PP |
88 | typedef struct tls_ext_ctx_cb { |
89 | uschar *certificate; | |
90 | uschar *privatekey; | |
f2de3a33 | 91 | #ifndef DISABLE_OCSP |
f5d78688 JH |
92 | BOOL is_server; |
93 | union { | |
94 | struct { | |
95 | uschar *file; | |
96 | uschar *file_expanded; | |
97 | OCSP_RESPONSE *response; | |
98 | } server; | |
99 | struct { | |
44662487 JH |
100 | X509_STORE *verify_store; /* non-null if status requested */ |
101 | BOOL verify_required; | |
f5d78688 JH |
102 | } client; |
103 | } u_ocsp; | |
3f7eeb86 | 104 | #endif |
7be682ca PP |
105 | uschar *dhparam; |
106 | /* these are cached from first expand */ | |
107 | uschar *server_cipher_list; | |
108 | /* only passed down to tls_error: */ | |
109 | host_item *host; | |
e51c7be2 JH |
110 | |
111 | #ifdef EXPERIMENTAL_CERTNAMES | |
112 | uschar * verify_cert_hostnames; | |
113 | #endif | |
7be682ca PP |
114 | } tls_ext_ctx_cb; |
115 | ||
116 | /* should figure out a cleanup of API to handle state preserved per | |
117 | implementation, for various reasons, which can be void * in the APIs. | |
118 | For now, we hack around it. */ | |
817d9f57 JH |
119 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
120 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
121 | |
122 | static int | |
983207c1 JH |
123 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
124 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ); | |
059ec3d9 | 125 | |
3f7eeb86 | 126 | /* Callbacks */ |
3bcbbbe2 | 127 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 128 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 129 | #endif |
f2de3a33 | 130 | #ifndef DISABLE_OCSP |
f5d78688 | 131 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
132 | #endif |
133 | ||
059ec3d9 PH |
134 | |
135 | /************************************************* | |
136 | * Handle TLS error * | |
137 | *************************************************/ | |
138 | ||
139 | /* Called from lots of places when errors occur before actually starting to do | |
140 | the TLS handshake, that is, while the session is still in clear. Always returns | |
141 | DEFER for a server and FAIL for a client so that most calls can use "return | |
142 | tls_error(...)" to do this processing and then give an appropriate return. A | |
143 | single function is used for both server and client, because it is called from | |
144 | some shared functions. | |
145 | ||
146 | Argument: | |
147 | prefix text to include in the logged error | |
148 | host NULL if setting up a server; | |
149 | the connected host if setting up a client | |
7199e1ee | 150 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
151 | |
152 | Returns: OK/DEFER/FAIL | |
153 | */ | |
154 | ||
155 | static int | |
7199e1ee | 156 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 157 | { |
7199e1ee TF |
158 | if (msg == NULL) |
159 | { | |
160 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 161 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
162 | } |
163 | ||
059ec3d9 PH |
164 | if (host == NULL) |
165 | { | |
7199e1ee | 166 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 167 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
168 | conn_info += 5; |
169 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
170 | conn_info, prefix, msg); | |
059ec3d9 PH |
171 | return DEFER; |
172 | } | |
173 | else | |
174 | { | |
175 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
7199e1ee | 176 | host->name, host->address, prefix, msg); |
059ec3d9 PH |
177 | return FAIL; |
178 | } | |
179 | } | |
180 | ||
181 | ||
182 | ||
183 | /************************************************* | |
184 | * Callback to generate RSA key * | |
185 | *************************************************/ | |
186 | ||
187 | /* | |
188 | Arguments: | |
189 | s SSL connection | |
190 | export not used | |
191 | keylength keylength | |
192 | ||
193 | Returns: pointer to generated key | |
194 | */ | |
195 | ||
196 | static RSA * | |
197 | rsa_callback(SSL *s, int export, int keylength) | |
198 | { | |
199 | RSA *rsa_key; | |
200 | export = export; /* Shut picky compilers up */ | |
201 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
202 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
203 | if (rsa_key == NULL) | |
204 | { | |
205 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
206 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
207 | ssl_errstring); | |
208 | return NULL; | |
209 | } | |
210 | return rsa_key; | |
211 | } | |
212 | ||
213 | ||
214 | ||
f5d78688 | 215 | /* Extreme debug |
f2de3a33 | 216 | #ifndef DISABLE_OCSP |
f5d78688 JH |
217 | void |
218 | x509_store_dump_cert_s_names(X509_STORE * store) | |
219 | { | |
220 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
221 | int i; | |
222 | static uschar name[256]; | |
223 | ||
224 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
225 | { | |
226 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
227 | if(tmp_obj->type == X509_LU_X509) | |
228 | { | |
229 | X509 * current_cert= tmp_obj->data.x509; | |
230 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
231 | debug_printf(" %s\n", name); | |
232 | } | |
233 | } | |
234 | } | |
235 | #endif | |
236 | */ | |
237 | ||
059ec3d9 PH |
238 | |
239 | /************************************************* | |
240 | * Callback for verification * | |
241 | *************************************************/ | |
242 | ||
243 | /* The SSL library does certificate verification if set up to do so. This | |
244 | callback has the current yes/no state is in "state". If verification succeeded, | |
245 | we set up the tls_peerdn string. If verification failed, what happens depends | |
246 | on whether the client is required to present a verifiable certificate or not. | |
247 | ||
248 | If verification is optional, we change the state to yes, but still log the | |
249 | verification error. For some reason (it really would help to have proper | |
250 | documentation of OpenSSL), this callback function then gets called again, this | |
251 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
252 | value, but we must take care not to set the private verified flag on the second | |
253 | time through. | |
254 | ||
255 | Note: this function is not called if the client fails to present a certificate | |
256 | when asked. We get here only if a certificate has been received. Handling of | |
257 | optional verification for this case is done when requesting SSL to verify, by | |
258 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
259 | ||
260 | Arguments: | |
261 | state current yes/no state as 1/0 | |
262 | x509ctx certificate information. | |
a2ff477a | 263 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
264 | |
265 | Returns: 1 if verified, 0 if not | |
266 | */ | |
267 | ||
268 | static int | |
421aff85 JH |
269 | verify_callback(int state, X509_STORE_CTX *x509ctx, |
270 | tls_support *tlsp, BOOL *calledp, BOOL *optionalp) | |
059ec3d9 | 271 | { |
421aff85 | 272 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
059ec3d9 PH |
273 | static uschar txt[256]; |
274 | ||
e51c7be2 | 275 | X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); |
059ec3d9 PH |
276 | |
277 | if (state == 0) | |
278 | { | |
279 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
421aff85 JH |
280 | X509_STORE_CTX_get_error_depth(x509ctx), |
281 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), | |
059ec3d9 | 282 | txt); |
a2ff477a JH |
283 | tlsp->certificate_verified = FALSE; |
284 | *calledp = TRUE; | |
9d1c15ef JH |
285 | if (!*optionalp) |
286 | { | |
421aff85 | 287 | tlsp->peercert = X509_dup(cert); |
9d1c15ef JH |
288 | return 0; /* reject */ |
289 | } | |
059ec3d9 PH |
290 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
291 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
292 | } |
293 | ||
421aff85 | 294 | else if (X509_STORE_CTX_get_error_depth(x509ctx) != 0) |
059ec3d9 | 295 | { |
93dcb1c2 | 296 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", |
421aff85 | 297 | X509_STORE_CTX_get_error_depth(x509ctx), txt); |
f2de3a33 | 298 | #ifndef DISABLE_OCSP |
f5d78688 JH |
299 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
300 | { /* client, wanting stapling */ | |
301 | /* Add the server cert's signing chain as the one | |
302 | for the verification of the OCSP stapled information. */ | |
303 | ||
304 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
421aff85 | 305 | cert)) |
f5d78688 JH |
306 | ERR_clear_error(); |
307 | } | |
308 | #endif | |
059ec3d9 PH |
309 | } |
310 | else | |
311 | { | |
e51c7be2 JH |
312 | #ifdef EXPERIMENTAL_CERTNAMES |
313 | uschar * verify_cert_hostnames; | |
314 | #endif | |
315 | ||
a2ff477a | 316 | tlsp->peerdn = txt; |
421aff85 | 317 | tlsp->peercert = X509_dup(cert); |
e51c7be2 JH |
318 | |
319 | #ifdef EXPERIMENTAL_CERTNAMES | |
320 | if ( tlsp == &tls_out | |
321 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
322 | /* client, wanting hostname check */ | |
323 | ||
324 | # if OPENSSL_VERSION_NUMBER >= 0x010100000L || OPENSSL_VERSION_NUMBER >= 0x010002000L | |
325 | { | |
326 | int sep = 0; | |
327 | uschar * list = verify_cert_hostnames; | |
328 | uschar * name; | |
329 | while (name = string_nextinlist(&list, &sep, NULL, 0)) | |
330 | if (X509_check_host(cert, name, 0, 0)) | |
331 | break; | |
332 | if (!name) | |
333 | { | |
334 | log_write(0, LOG_MAIN, | |
335 | "SSL verify error: certificate name mismatch: \"%s\"\n", txt); | |
336 | return 0; /* reject */ | |
337 | } | |
338 | } | |
339 | # else | |
340 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) | |
341 | { | |
342 | log_write(0, LOG_MAIN, | |
343 | "SSL verify error: certificate name mismatch: \"%s\"\n", txt); | |
344 | return 0; /* reject */ | |
345 | } | |
346 | # endif | |
347 | #endif | |
348 | ||
93dcb1c2 JH |
349 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
350 | *calledp ? "" : " authenticated", txt); | |
351 | if (!*calledp) tlsp->certificate_verified = TRUE; | |
352 | *calledp = TRUE; | |
059ec3d9 PH |
353 | } |
354 | ||
059ec3d9 PH |
355 | return 1; /* accept */ |
356 | } | |
357 | ||
a2ff477a JH |
358 | static int |
359 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
360 | { | |
f5d78688 | 361 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); |
a2ff477a JH |
362 | } |
363 | ||
364 | static int | |
365 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
366 | { | |
f5d78688 | 367 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); |
a2ff477a JH |
368 | } |
369 | ||
059ec3d9 PH |
370 | |
371 | ||
372 | /************************************************* | |
373 | * Information callback * | |
374 | *************************************************/ | |
375 | ||
376 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
377 | are doing. We copy the string to the debugging output when TLS debugging has |
378 | been requested. | |
059ec3d9 PH |
379 | |
380 | Arguments: | |
381 | s the SSL connection | |
382 | where | |
383 | ret | |
384 | ||
385 | Returns: nothing | |
386 | */ | |
387 | ||
388 | static void | |
389 | info_callback(SSL *s, int where, int ret) | |
390 | { | |
391 | where = where; | |
392 | ret = ret; | |
393 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
394 | } | |
395 | ||
396 | ||
397 | ||
398 | /************************************************* | |
399 | * Initialize for DH * | |
400 | *************************************************/ | |
401 | ||
402 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
403 | ||
404 | Arguments: | |
a799883d | 405 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 406 | host connected host, if client; NULL if server |
059ec3d9 PH |
407 | |
408 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
409 | */ | |
410 | ||
411 | static BOOL | |
a799883d | 412 | init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host) |
059ec3d9 | 413 | { |
059ec3d9 PH |
414 | BIO *bio; |
415 | DH *dh; | |
416 | uschar *dhexpanded; | |
a799883d | 417 | const char *pem; |
059ec3d9 PH |
418 | |
419 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
420 | return FALSE; | |
421 | ||
a799883d | 422 | if (dhexpanded == NULL || *dhexpanded == '\0') |
059ec3d9 | 423 | { |
a799883d | 424 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
059ec3d9 | 425 | } |
a799883d | 426 | else if (dhexpanded[0] == '/') |
059ec3d9 | 427 | { |
a799883d PP |
428 | bio = BIO_new_file(CS dhexpanded, "r"); |
429 | if (bio == NULL) | |
059ec3d9 | 430 | { |
7199e1ee | 431 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
432 | host, US strerror(errno)); |
433 | return FALSE; | |
059ec3d9 | 434 | } |
a799883d PP |
435 | } |
436 | else | |
437 | { | |
438 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 439 | { |
a799883d PP |
440 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
441 | return TRUE; | |
059ec3d9 | 442 | } |
a799883d PP |
443 | |
444 | pem = std_dh_prime_named(dhexpanded); | |
445 | if (!pem) | |
446 | { | |
447 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
448 | host, US strerror(errno)); | |
449 | return FALSE; | |
450 | } | |
451 | bio = BIO_new_mem_buf(CS pem, -1); | |
452 | } | |
453 | ||
454 | dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL); | |
455 | if (dh == NULL) | |
456 | { | |
059ec3d9 | 457 | BIO_free(bio); |
a799883d PP |
458 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
459 | host, NULL); | |
460 | return FALSE; | |
461 | } | |
462 | ||
463 | /* Even if it is larger, we silently return success rather than cause things | |
464 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
465 | * debatable choice. */ | |
466 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
467 | { | |
468 | DEBUG(D_tls) | |
469 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
470 | 8*DH_size(dh), tls_dh_max_bits); | |
471 | } | |
472 | else | |
473 | { | |
474 | SSL_CTX_set_tmp_dh(sctx, dh); | |
475 | DEBUG(D_tls) | |
476 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
477 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
478 | } |
479 | ||
a799883d PP |
480 | DH_free(dh); |
481 | BIO_free(bio); | |
482 | ||
483 | return TRUE; | |
059ec3d9 PH |
484 | } |
485 | ||
486 | ||
487 | ||
488 | ||
f2de3a33 | 489 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
490 | /************************************************* |
491 | * Load OCSP information into state * | |
492 | *************************************************/ | |
493 | ||
f5d78688 | 494 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
495 | caller has determined this is needed. Checks validity. Debugs a message |
496 | if invalid. | |
497 | ||
498 | ASSUMES: single response, for single cert. | |
499 | ||
500 | Arguments: | |
501 | sctx the SSL_CTX* to update | |
502 | cbinfo various parts of session state | |
503 | expanded the filename putatively holding an OCSP response | |
504 | ||
505 | */ | |
506 | ||
507 | static void | |
f5d78688 | 508 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 PP |
509 | { |
510 | BIO *bio; | |
511 | OCSP_RESPONSE *resp; | |
512 | OCSP_BASICRESP *basic_response; | |
513 | OCSP_SINGLERESP *single_response; | |
514 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
515 | X509_STORE *store; | |
516 | unsigned long verify_flags; | |
517 | int status, reason, i; | |
518 | ||
f5d78688 JH |
519 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
520 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 521 | { |
f5d78688 JH |
522 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
523 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
524 | } |
525 | ||
f5d78688 | 526 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); |
3f7eeb86 PP |
527 | if (!bio) |
528 | { | |
529 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 530 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
531 | return; |
532 | } | |
533 | ||
534 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
535 | BIO_free(bio); | |
536 | if (!resp) | |
537 | { | |
538 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
539 | return; | |
540 | } | |
541 | ||
542 | status = OCSP_response_status(resp); | |
543 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
544 | { | |
545 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
546 | OCSP_response_status_str(status), status); | |
f5d78688 | 547 | goto bad; |
3f7eeb86 PP |
548 | } |
549 | ||
550 | basic_response = OCSP_response_get1_basic(resp); | |
551 | if (!basic_response) | |
552 | { | |
553 | DEBUG(D_tls) | |
554 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 555 | goto bad; |
3f7eeb86 PP |
556 | } |
557 | ||
558 | store = SSL_CTX_get_cert_store(sctx); | |
559 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
560 | ||
561 | /* May need to expose ability to adjust those flags? | |
562 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
563 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
564 | ||
565 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
566 | if (i <= 0) | |
567 | { | |
568 | DEBUG(D_tls) { | |
569 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
570 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
571 | } |
572 | goto bad; | |
3f7eeb86 PP |
573 | } |
574 | ||
575 | /* Here's the simplifying assumption: there's only one response, for the | |
576 | one certificate we use, and nothing for anything else in a chain. If this | |
577 | proves false, we need to extract a cert id from our issued cert | |
578 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
579 | right cert in the stack and then calls OCSP_single_get0_status()). | |
580 | ||
581 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
582 | single_response = OCSP_resp_get0(basic_response, 0); | |
583 | if (!single_response) | |
584 | { | |
585 | DEBUG(D_tls) | |
586 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 587 | goto bad; |
3f7eeb86 PP |
588 | } |
589 | ||
590 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 591 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 592 | { |
f5d78688 JH |
593 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
594 | OCSP_cert_status_str(status), status, | |
595 | OCSP_crl_reason_str(reason), reason); | |
596 | goto bad; | |
3f7eeb86 PP |
597 | } |
598 | ||
599 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
600 | { | |
601 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 602 | goto bad; |
3f7eeb86 PP |
603 | } |
604 | ||
f5d78688 | 605 | supply_response: |
018058b2 | 606 | cbinfo->u_ocsp.server.response = resp; |
f5d78688 JH |
607 | return; |
608 | ||
609 | bad: | |
018058b2 JH |
610 | if (running_in_test_harness) |
611 | { | |
612 | extern char ** environ; | |
613 | uschar ** p; | |
614 | for (p = USS environ; *p != NULL; p++) | |
615 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
616 | { | |
617 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
618 | goto supply_response; | |
619 | } | |
620 | } | |
f5d78688 | 621 | return; |
3f7eeb86 | 622 | } |
f2de3a33 | 623 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
624 | |
625 | ||
626 | ||
627 | ||
7be682ca PP |
628 | /************************************************* |
629 | * Expand key and cert file specs * | |
630 | *************************************************/ | |
631 | ||
f5d78688 | 632 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
633 | new context, if Server Name Indication was used and tls_sni was seen in |
634 | the certificate string. | |
635 | ||
636 | Arguments: | |
637 | sctx the SSL_CTX* to update | |
638 | cbinfo various parts of session state | |
639 | ||
640 | Returns: OK/DEFER/FAIL | |
641 | */ | |
642 | ||
643 | static int | |
3f7eeb86 | 644 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
645 | { |
646 | uschar *expanded; | |
647 | ||
648 | if (cbinfo->certificate == NULL) | |
649 | return OK; | |
650 | ||
d9b2312b JH |
651 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
652 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
653 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
654 | ) | |
7be682ca PP |
655 | reexpand_tls_files_for_sni = TRUE; |
656 | ||
657 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
658 | return DEFER; | |
659 | ||
660 | if (expanded != NULL) | |
661 | { | |
662 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
663 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
664 | return tls_error(string_sprintf( | |
665 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
666 | cbinfo->host, NULL); | |
667 | } | |
668 | ||
669 | if (cbinfo->privatekey != NULL && | |
670 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
671 | return DEFER; | |
672 | ||
673 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
674 | of the expansion is an empty string, ignore it also, and assume the private | |
675 | key is in the same file as the certificate. */ | |
676 | ||
677 | if (expanded != NULL && *expanded != 0) | |
678 | { | |
679 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
680 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
681 | return tls_error(string_sprintf( | |
682 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
683 | } | |
684 | ||
f2de3a33 | 685 | #ifndef DISABLE_OCSP |
f5d78688 | 686 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) |
3f7eeb86 | 687 | { |
f5d78688 | 688 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) |
3f7eeb86 PP |
689 | return DEFER; |
690 | ||
691 | if (expanded != NULL && *expanded != 0) | |
692 | { | |
693 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f5d78688 JH |
694 | if (cbinfo->u_ocsp.server.file_expanded && |
695 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 PP |
696 | { |
697 | DEBUG(D_tls) | |
698 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
699 | } else { | |
700 | ocsp_load_response(sctx, cbinfo, expanded); | |
701 | } | |
702 | } | |
703 | } | |
704 | #endif | |
705 | ||
7be682ca PP |
706 | return OK; |
707 | } | |
708 | ||
709 | ||
710 | ||
711 | ||
712 | /************************************************* | |
713 | * Callback to handle SNI * | |
714 | *************************************************/ | |
715 | ||
716 | /* Called when acting as server during the TLS session setup if a Server Name | |
717 | Indication extension was sent by the client. | |
718 | ||
719 | API documentation is OpenSSL s_server.c implementation. | |
720 | ||
721 | Arguments: | |
722 | s SSL* of the current session | |
723 | ad unknown (part of OpenSSL API) (unused) | |
724 | arg Callback of "our" registered data | |
725 | ||
726 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
727 | */ | |
728 | ||
3bcbbbe2 | 729 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
730 | static int |
731 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
732 | { | |
733 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 734 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 735 | int rc; |
3f0945ff | 736 | int old_pool = store_pool; |
7be682ca PP |
737 | |
738 | if (!servername) | |
739 | return SSL_TLSEXT_ERR_OK; | |
740 | ||
3f0945ff | 741 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
742 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
743 | ||
744 | /* Make the extension value available for expansion */ | |
3f0945ff | 745 | store_pool = POOL_PERM; |
817d9f57 | 746 | tls_in.sni = string_copy(US servername); |
3f0945ff | 747 | store_pool = old_pool; |
7be682ca PP |
748 | |
749 | if (!reexpand_tls_files_for_sni) | |
750 | return SSL_TLSEXT_ERR_OK; | |
751 | ||
752 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
753 | not confident that memcpy wouldn't break some internal reference counting. | |
754 | Especially since there's a references struct member, which would be off. */ | |
755 | ||
817d9f57 JH |
756 | server_sni = SSL_CTX_new(SSLv23_server_method()); |
757 | if (!server_sni) | |
7be682ca PP |
758 | { |
759 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
760 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
761 | return SSL_TLSEXT_ERR_NOACK; | |
762 | } | |
763 | ||
764 | /* Not sure how many of these are actually needed, since SSL object | |
765 | already exists. Might even need this selfsame callback, for reneg? */ | |
766 | ||
817d9f57 JH |
767 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
768 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
769 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
770 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
771 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
772 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
7be682ca | 773 | if (cbinfo->server_cipher_list) |
817d9f57 | 774 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
f2de3a33 | 775 | #ifndef DISABLE_OCSP |
f5d78688 | 776 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 777 | { |
f5d78688 | 778 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 779 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
780 | } |
781 | #endif | |
7be682ca | 782 | |
983207c1 | 783 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server); |
7be682ca PP |
784 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
785 | ||
3f7eeb86 PP |
786 | /* do this after setup_certs, because this can require the certs for verifying |
787 | OCSP information. */ | |
817d9f57 | 788 | rc = tls_expand_session_files(server_sni, cbinfo); |
7be682ca PP |
789 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
790 | ||
389ca47a | 791 | rc = init_dh(server_sni, cbinfo->dhparam, NULL); |
a799883d PP |
792 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
793 | ||
7be682ca | 794 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 795 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
796 | |
797 | return SSL_TLSEXT_ERR_OK; | |
798 | } | |
3bcbbbe2 | 799 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
800 | |
801 | ||
802 | ||
803 | ||
f2de3a33 | 804 | #ifndef DISABLE_OCSP |
f5d78688 | 805 | |
3f7eeb86 PP |
806 | /************************************************* |
807 | * Callback to handle OCSP Stapling * | |
808 | *************************************************/ | |
809 | ||
810 | /* Called when acting as server during the TLS session setup if the client | |
811 | requests OCSP information with a Certificate Status Request. | |
812 | ||
813 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
814 | project. | |
815 | ||
816 | */ | |
817 | ||
818 | static int | |
f5d78688 | 819 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
820 | { |
821 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
822 | uschar *response_der; | |
823 | int response_der_len; | |
824 | ||
af4a1bca JH |
825 | DEBUG(D_tls) |
826 | debug_printf("Received TLS status request (OCSP stapling); %s response.", | |
f5d78688 JH |
827 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
828 | ||
44662487 | 829 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 830 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
831 | return SSL_TLSEXT_ERR_NOACK; |
832 | ||
833 | response_der = NULL; | |
44662487 JH |
834 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, |
835 | &response_der); | |
3f7eeb86 PP |
836 | if (response_der_len <= 0) |
837 | return SSL_TLSEXT_ERR_NOACK; | |
838 | ||
5e55c7a9 | 839 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 840 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
841 | return SSL_TLSEXT_ERR_OK; |
842 | } | |
843 | ||
3f7eeb86 | 844 | |
f5d78688 JH |
845 | static void |
846 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
847 | { | |
848 | BIO_printf(bp, "\t%s: ", str); | |
849 | ASN1_GENERALIZEDTIME_print(bp, time); | |
850 | BIO_puts(bp, "\n"); | |
851 | } | |
852 | ||
853 | static int | |
854 | tls_client_stapling_cb(SSL *s, void *arg) | |
855 | { | |
856 | tls_ext_ctx_cb * cbinfo = arg; | |
857 | const unsigned char * p; | |
858 | int len; | |
859 | OCSP_RESPONSE * rsp; | |
860 | OCSP_BASICRESP * bs; | |
861 | int i; | |
862 | ||
863 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
864 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
865 | if(!p) | |
866 | { | |
44662487 JH |
867 | /* Expect this when we requested ocsp but got none */ |
868 | if ( cbinfo->u_ocsp.client.verify_required | |
869 | && log_extra_selector & LX_tls_cipher) | |
870 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); | |
f5d78688 JH |
871 | else |
872 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 873 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 874 | } |
018058b2 | 875 | |
f5d78688 JH |
876 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
877 | { | |
018058b2 | 878 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
879 | if (log_extra_selector & LX_tls_cipher) |
880 | log_write(0, LOG_MAIN, "Received TLS status response, parse error"); | |
881 | else | |
882 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
883 | return 0; | |
884 | } | |
885 | ||
886 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
887 | { | |
018058b2 | 888 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
889 | if (log_extra_selector & LX_tls_cipher) |
890 | log_write(0, LOG_MAIN, "Received TLS status response, error parsing response"); | |
891 | else | |
892 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
893 | OCSP_RESPONSE_free(rsp); | |
894 | return 0; | |
895 | } | |
896 | ||
897 | /* We'd check the nonce here if we'd put one in the request. */ | |
898 | /* However that would defeat cacheability on the server so we don't. */ | |
899 | ||
f5d78688 JH |
900 | /* This section of code reworked from OpenSSL apps source; |
901 | The OpenSSL Project retains copyright: | |
902 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
903 | */ | |
904 | { | |
905 | BIO * bp = NULL; | |
f5d78688 JH |
906 | int status, reason; |
907 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
908 | ||
909 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
910 | ||
911 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
912 | ||
913 | /* Use the chain that verified the server cert to verify the stapled info */ | |
914 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
915 | ||
44662487 JH |
916 | if ((i = OCSP_basic_verify(bs, NULL, |
917 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
f5d78688 | 918 | { |
018058b2 | 919 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
920 | BIO_printf(bp, "OCSP response verify failure\n"); |
921 | ERR_print_errors(bp); | |
44662487 | 922 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 JH |
923 | goto out; |
924 | } | |
925 | ||
926 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
927 | ||
928 | { | |
929 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
930 | OCSP_SINGLERESP * single; | |
931 | ||
932 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
933 | { | |
018058b2 | 934 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
935 | log_write(0, LOG_MAIN, "OCSP stapling " |
936 | "with multiple responses not handled"); | |
937 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
f5d78688 JH |
938 | goto out; |
939 | } | |
940 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
941 | status = OCSP_single_get0_status(single, &reason, &rev, |
942 | &thisupd, &nextupd); | |
f5d78688 JH |
943 | } |
944 | ||
f5d78688 JH |
945 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
946 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
947 | if (!OCSP_check_validity(thisupd, nextupd, |
948 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 949 | { |
018058b2 | 950 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
951 | DEBUG(D_tls) ERR_print_errors(bp); |
952 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
44662487 | 953 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 954 | } |
44662487 | 955 | else |
f5d78688 | 956 | { |
44662487 JH |
957 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
958 | OCSP_cert_status_str(status)); | |
959 | switch(status) | |
960 | { | |
961 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 962 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 963 | i = 1; |
44662487 JH |
964 | break; |
965 | case V_OCSP_CERTSTATUS_REVOKED: | |
018058b2 | 966 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
967 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
968 | reason != -1 ? "; reason: " : "", | |
969 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
970 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
971 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
972 | break; | |
973 | default: | |
018058b2 | 974 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
975 | log_write(0, LOG_MAIN, |
976 | "Server certificate status unknown, in OCSP stapling"); | |
977 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
978 | break; | |
979 | } | |
f5d78688 JH |
980 | } |
981 | out: | |
982 | BIO_free(bp); | |
983 | } | |
984 | ||
985 | OCSP_RESPONSE_free(rsp); | |
986 | return i; | |
987 | } | |
f2de3a33 | 988 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
989 | |
990 | ||
991 | ||
059ec3d9 PH |
992 | /************************************************* |
993 | * Initialize for TLS * | |
994 | *************************************************/ | |
995 | ||
e51c7be2 JH |
996 | /* Called from both server and client code, to do preliminary initialization |
997 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
998 | |
999 | Arguments: | |
1000 | host connected host, if client; NULL if server | |
1001 | dhparam DH parameter file | |
1002 | certificate certificate file | |
1003 | privatekey private key | |
f5d78688 | 1004 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1005 | addr address if client; NULL if server (for some randomness) |
e51c7be2 | 1006 | cbp place to put allocated context |
059ec3d9 PH |
1007 | |
1008 | Returns: OK/DEFER/FAIL | |
1009 | */ | |
1010 | ||
1011 | static int | |
817d9f57 | 1012 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1013 | uschar *privatekey, |
f2de3a33 | 1014 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1015 | uschar *ocsp_file, |
1016 | #endif | |
817d9f57 | 1017 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 1018 | { |
77bb000f | 1019 | long init_options; |
7be682ca | 1020 | int rc; |
77bb000f | 1021 | BOOL okay; |
7be682ca PP |
1022 | tls_ext_ctx_cb *cbinfo; |
1023 | ||
1024 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1025 | cbinfo->certificate = certificate; | |
1026 | cbinfo->privatekey = privatekey; | |
f2de3a33 | 1027 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1028 | if ((cbinfo->is_server = host==NULL)) |
1029 | { | |
1030 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1031 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1032 | cbinfo->u_ocsp.server.response = NULL; | |
1033 | } | |
1034 | else | |
1035 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1036 | #endif |
7be682ca PP |
1037 | cbinfo->dhparam = dhparam; |
1038 | cbinfo->host = host; | |
77bb000f | 1039 | |
059ec3d9 PH |
1040 | SSL_load_error_strings(); /* basic set up */ |
1041 | OpenSSL_add_ssl_algorithms(); | |
1042 | ||
388d6564 | 1043 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 1044 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1045 | list of available digests. */ |
1046 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1047 | #endif |
a0475b69 | 1048 | |
f0f5a555 PP |
1049 | /* Create a context. |
1050 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1051 | negotiation in the different methods; as far as I can tell, the only | |
1052 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1053 | when OpenSSL is built without SSLv2 support. | |
1054 | By disabling with openssl_options, we can let admins re-enable with the | |
1055 | existing knob. */ | |
059ec3d9 | 1056 | |
817d9f57 | 1057 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
1058 | SSLv23_server_method() : SSLv23_client_method()); |
1059 | ||
817d9f57 | 1060 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
1061 | |
1062 | /* It turns out that we need to seed the random number generator this early in | |
1063 | order to get the full complement of ciphers to work. It took me roughly a day | |
1064 | of work to discover this by experiment. | |
1065 | ||
1066 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1067 | there. Otherwise, we have to make something up as best we can. Double check | |
1068 | afterwards. */ | |
1069 | ||
1070 | if (!RAND_status()) | |
1071 | { | |
1072 | randstuff r; | |
9e3331ea | 1073 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1074 | r.p = getpid(); |
1075 | ||
1076 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1077 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1078 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1079 | ||
1080 | if (!RAND_status()) | |
7199e1ee | 1081 | return tls_error(US"RAND_status", host, |
5ca6d115 | 1082 | US"unable to seed random number generator"); |
059ec3d9 PH |
1083 | } |
1084 | ||
1085 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1086 | level. */ | |
1087 | ||
817d9f57 | 1088 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 1089 | |
c80c5570 | 1090 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 1091 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1092 | |
77bb000f PP |
1093 | /* Apply administrator-supplied work-arounds. |
1094 | Historically we applied just one requested option, | |
1095 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1096 | moved to an administrator-controlled list of options to specify and | |
1097 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1098 | |
77bb000f PP |
1099 | No OpenSSL version number checks: the options we accept depend upon the |
1100 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1101 | |
77bb000f PP |
1102 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
1103 | if (!okay) | |
73a46702 | 1104 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
1105 | |
1106 | if (init_options) | |
1107 | { | |
1108 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 1109 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
1110 | return tls_error(string_sprintf( |
1111 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1112 | } | |
1113 | else | |
1114 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
1115 | |
1116 | /* Initialize with DH parameters if supplied */ | |
1117 | ||
817d9f57 | 1118 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; |
059ec3d9 | 1119 | |
3f7eeb86 | 1120 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1121 | |
817d9f57 | 1122 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 1123 | if (rc != OK) return rc; |
c91535f3 | 1124 | |
7be682ca | 1125 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 1126 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
f5d78688 | 1127 | if (host == NULL) /* server */ |
3f0945ff | 1128 | { |
f2de3a33 | 1129 | # ifndef DISABLE_OCSP |
f5d78688 | 1130 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1131 | the option exists, not what the current expansion might be, as SNI might |
1132 | change the certificate and OCSP file in use between now and the time the | |
1133 | callback is invoked. */ | |
f5d78688 | 1134 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1135 | { |
f5d78688 | 1136 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); |
5e55c7a9 | 1137 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); |
3f7eeb86 | 1138 | } |
f5d78688 | 1139 | # endif |
3f0945ff PP |
1140 | /* We always do this, so that $tls_sni is available even if not used in |
1141 | tls_certificate */ | |
817d9f57 JH |
1142 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
1143 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 1144 | } |
f2de3a33 | 1145 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1146 | else /* client */ |
1147 | if(ocsp_file) /* wanting stapling */ | |
1148 | { | |
1149 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1150 | { | |
1151 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1152 | return FAIL; | |
1153 | } | |
1154 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1155 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1156 | } | |
1157 | # endif | |
7be682ca | 1158 | #endif |
059ec3d9 | 1159 | |
e51c7be2 JH |
1160 | #ifdef EXPERIMENTAL_CERTNAMES |
1161 | cbinfo->verify_cert_hostnames = NULL; | |
1162 | #endif | |
1163 | ||
059ec3d9 PH |
1164 | /* Set up the RSA callback */ |
1165 | ||
817d9f57 | 1166 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
1167 | |
1168 | /* Finally, set the timeout, and we are done */ | |
1169 | ||
817d9f57 | 1170 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 1171 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1172 | |
817d9f57 | 1173 | *cbp = cbinfo; |
7be682ca | 1174 | |
059ec3d9 PH |
1175 | return OK; |
1176 | } | |
1177 | ||
1178 | ||
1179 | ||
1180 | ||
1181 | /************************************************* | |
1182 | * Get name of cipher in use * | |
1183 | *************************************************/ | |
1184 | ||
817d9f57 | 1185 | /* |
059ec3d9 | 1186 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1187 | buffer to use for answer |
1188 | size of buffer | |
1189 | pointer to number of bits for cipher | |
059ec3d9 PH |
1190 | Returns: nothing |
1191 | */ | |
1192 | ||
1193 | static void | |
817d9f57 | 1194 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1195 | { |
57b3a7f5 PP |
1196 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1197 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1198 | the accessor functions use const in the prototype. */ | |
1199 | const SSL_CIPHER *c; | |
d9784128 | 1200 | const uschar *ver; |
059ec3d9 | 1201 | |
d9784128 | 1202 | ver = (const uschar *)SSL_get_version(ssl); |
059ec3d9 | 1203 | |
57b3a7f5 | 1204 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1205 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1206 | |
817d9f57 JH |
1207 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1208 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1209 | |
1210 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1211 | } | |
1212 | ||
1213 | ||
1214 | ||
1215 | ||
1216 | ||
1217 | /************************************************* | |
1218 | * Set up for verifying certificates * | |
1219 | *************************************************/ | |
1220 | ||
1221 | /* Called by both client and server startup | |
1222 | ||
1223 | Arguments: | |
7be682ca | 1224 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1225 | certs certs file or NULL |
1226 | crl CRL file or NULL | |
1227 | host NULL in a server; the remote host in a client | |
1228 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1229 | otherwise passed as FALSE | |
983207c1 | 1230 | cert_vfy_cb Callback function for certificate verification |
059ec3d9 PH |
1231 | |
1232 | Returns: OK/DEFER/FAIL | |
1233 | */ | |
1234 | ||
1235 | static int | |
983207c1 JH |
1236 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
1237 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ) | |
059ec3d9 PH |
1238 | { |
1239 | uschar *expcerts, *expcrl; | |
1240 | ||
1241 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1242 | return DEFER; | |
1243 | ||
26e72755 | 1244 | if (expcerts != NULL && *expcerts != '\0') |
059ec3d9 PH |
1245 | { |
1246 | struct stat statbuf; | |
7be682ca | 1247 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
7199e1ee | 1248 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
1249 | |
1250 | if (Ustat(expcerts, &statbuf) < 0) | |
1251 | { | |
1252 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1253 | "failed to stat %s for certificates", expcerts); | |
1254 | return DEFER; | |
1255 | } | |
1256 | else | |
1257 | { | |
1258 | uschar *file, *dir; | |
1259 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1260 | { file = NULL; dir = expcerts; } | |
1261 | else | |
1262 | { file = expcerts; dir = NULL; } | |
1263 | ||
1264 | /* If a certificate file is empty, the next function fails with an | |
1265 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1266 | certificates are recognized, but the error message is still misleading (it | |
1267 | says no certificate was supplied.) But this is better. */ | |
1268 | ||
1269 | if ((file == NULL || statbuf.st_size > 0) && | |
7be682ca | 1270 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) |
7199e1ee | 1271 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 PH |
1272 | |
1273 | if (file != NULL) | |
1274 | { | |
7be682ca | 1275 | SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); |
059ec3d9 PH |
1276 | } |
1277 | } | |
1278 | ||
1279 | /* Handle a certificate revocation list. */ | |
1280 | ||
1281 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1282 | ||
8b417f2c PH |
1283 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1284 | * merely reformatted it into the Exim code style.) | |
1285 | ||
1286 | * "From here I changed the code to add support for multiple crl's | |
1287 | * in pem format in one file or to support hashed directory entries in | |
1288 | * pem format instead of a file. This method now uses the library function | |
1289 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1290 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1291 | * itself in the verify callback." */ | |
1292 | ||
059ec3d9 PH |
1293 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1294 | if (expcrl != NULL && *expcrl != 0) | |
1295 | { | |
8b417f2c PH |
1296 | struct stat statbufcrl; |
1297 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1298 | { | |
1299 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1300 | "failed to stat %s for certificates revocation lists", expcrl); | |
1301 | return DEFER; | |
1302 | } | |
1303 | else | |
059ec3d9 | 1304 | { |
8b417f2c PH |
1305 | /* is it a file or directory? */ |
1306 | uschar *file, *dir; | |
7be682ca | 1307 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1308 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1309 | { |
8b417f2c PH |
1310 | file = NULL; |
1311 | dir = expcrl; | |
1312 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1313 | } |
1314 | else | |
1315 | { | |
8b417f2c PH |
1316 | file = expcrl; |
1317 | dir = NULL; | |
1318 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1319 | } |
8b417f2c | 1320 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1321 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1322 | |
1323 | /* setting the flags to check against the complete crl chain */ | |
1324 | ||
1325 | X509_STORE_set_flags(cvstore, | |
1326 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1327 | } |
059ec3d9 PH |
1328 | } |
1329 | ||
1330 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1331 | ||
1332 | /* If verification is optional, don't fail if no certificate */ | |
1333 | ||
7be682ca | 1334 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1335 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 1336 | cert_vfy_cb); |
059ec3d9 PH |
1337 | } |
1338 | ||
1339 | return OK; | |
1340 | } | |
1341 | ||
1342 | ||
1343 | ||
1344 | /************************************************* | |
1345 | * Start a TLS session in a server * | |
1346 | *************************************************/ | |
1347 | ||
1348 | /* This is called when Exim is running as a server, after having received | |
1349 | the STARTTLS command. It must respond to that command, and then negotiate | |
1350 | a TLS session. | |
1351 | ||
1352 | Arguments: | |
1353 | require_ciphers allowed ciphers | |
1354 | ||
1355 | Returns: OK on success | |
1356 | DEFER for errors before the start of the negotiation | |
1357 | FAIL for errors during the negotation; the server can't | |
1358 | continue running. | |
1359 | */ | |
1360 | ||
1361 | int | |
17c76198 | 1362 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1363 | { |
1364 | int rc; | |
1365 | uschar *expciphers; | |
7be682ca | 1366 | tls_ext_ctx_cb *cbinfo; |
817d9f57 | 1367 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1368 | |
1369 | /* Check for previous activation */ | |
1370 | ||
817d9f57 | 1371 | if (tls_in.active >= 0) |
059ec3d9 | 1372 | { |
5ca6d115 | 1373 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1374 | smtp_printf("554 Already in TLS\r\n"); |
1375 | return FAIL; | |
1376 | } | |
1377 | ||
1378 | /* Initialize the SSL library. If it fails, it will already have logged | |
1379 | the error. */ | |
1380 | ||
817d9f57 | 1381 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 1382 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1383 | tls_ocsp_file, |
1384 | #endif | |
817d9f57 | 1385 | NULL, &server_static_cbinfo); |
059ec3d9 | 1386 | if (rc != OK) return rc; |
817d9f57 | 1387 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1388 | |
1389 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1390 | return FAIL; | |
1391 | ||
1392 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1393 | were historically separated by underscores. So that I can use either form in my |
1394 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1395 | */ | |
059ec3d9 PH |
1396 | |
1397 | if (expciphers != NULL) | |
1398 | { | |
1399 | uschar *s = expciphers; | |
1400 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1401 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1402 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1403 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1404 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1405 | } |
1406 | ||
1407 | /* If this is a host for which certificate verification is mandatory or | |
1408 | optional, set up appropriately. */ | |
1409 | ||
817d9f57 | 1410 | tls_in.certificate_verified = FALSE; |
a2ff477a | 1411 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1412 | |
1413 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1414 | { | |
983207c1 JH |
1415 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1416 | FALSE, verify_callback_server); | |
059ec3d9 | 1417 | if (rc != OK) return rc; |
a2ff477a | 1418 | server_verify_optional = FALSE; |
059ec3d9 PH |
1419 | } |
1420 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1421 | { | |
983207c1 JH |
1422 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1423 | TRUE, verify_callback_server); | |
059ec3d9 | 1424 | if (rc != OK) return rc; |
a2ff477a | 1425 | server_verify_optional = TRUE; |
059ec3d9 PH |
1426 | } |
1427 | ||
1428 | /* Prepare for new connection */ | |
1429 | ||
817d9f57 | 1430 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1431 | |
1432 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1433 | * | |
1434 | * With the SSL_clear(), we get strange interoperability bugs with | |
1435 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1436 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1437 | * | |
1438 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1439 | * session shutdown. In this case, we have a brand new object and there's no | |
1440 | * obvious reason to immediately clear it. I'm guessing that this was | |
1441 | * originally added because of incomplete initialisation which the clear fixed, | |
1442 | * in some historic release. | |
1443 | */ | |
059ec3d9 PH |
1444 | |
1445 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1446 | on connection, where outputting anything now upsets the clients and tends to | |
1447 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1448 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1449 | mode, the fflush() happens when smtp_getc() is called. */ | |
1450 | ||
817d9f57 JH |
1451 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1452 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1453 | { |
1454 | smtp_printf("220 TLS go ahead\r\n"); | |
1455 | fflush(smtp_out); | |
1456 | } | |
1457 | ||
1458 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1459 | that the OpenSSL library doesn't. */ | |
1460 | ||
817d9f57 JH |
1461 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1462 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1463 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1464 | |
1465 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1466 | ||
1467 | sigalrm_seen = FALSE; | |
1468 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1469 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1470 | alarm(0); |
1471 | ||
1472 | if (rc <= 0) | |
1473 | { | |
7199e1ee | 1474 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1475 | if (ERR_get_error() == 0) |
1476 | log_write(0, LOG_MAIN, | |
a053d125 | 1477 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1478 | return FAIL; |
1479 | } | |
1480 | ||
1481 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1482 | ||
1483 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1484 | and initialize things. */ | |
1485 | ||
817d9f57 JH |
1486 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1487 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1488 | |
1489 | DEBUG(D_tls) | |
1490 | { | |
1491 | uschar buf[2048]; | |
817d9f57 | 1492 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1493 | debug_printf("Shared ciphers: %s\n", buf); |
1494 | } | |
1495 | ||
9d1c15ef JH |
1496 | /* Record the certificate we presented */ |
1497 | { | |
1498 | X509 * crt = SSL_get_certificate(server_ssl); | |
1499 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
1500 | } | |
059ec3d9 | 1501 | |
817d9f57 JH |
1502 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1503 | Client-side (tls_out) reads (seem to?) go via | |
1504 | smtp_read_response()/ip_recv(). | |
1505 | Hence no need to duplicate for _in and _out. | |
1506 | */ | |
059ec3d9 PH |
1507 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1508 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1509 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1510 | ||
1511 | receive_getc = tls_getc; | |
1512 | receive_ungetc = tls_ungetc; | |
1513 | receive_feof = tls_feof; | |
1514 | receive_ferror = tls_ferror; | |
58eb016e | 1515 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1516 | |
817d9f57 | 1517 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1518 | return OK; |
1519 | } | |
1520 | ||
1521 | ||
1522 | ||
1523 | ||
1524 | ||
1525 | /************************************************* | |
1526 | * Start a TLS session in a client * | |
1527 | *************************************************/ | |
1528 | ||
1529 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1530 | ||
1531 | Argument: | |
1532 | fd the fd of the connection | |
1533 | host connected host (for messages) | |
83da1223 | 1534 | addr the first address |
65867078 | 1535 | ob smtp transport options |
059ec3d9 PH |
1536 | |
1537 | Returns: OK on success | |
1538 | FAIL otherwise - note that tls_error() will not give DEFER | |
1539 | because this is not a server | |
1540 | */ | |
1541 | ||
1542 | int | |
f5d78688 | 1543 | tls_client_start(int fd, host_item *host, address_item *addr, |
65867078 | 1544 | void *v_ob) |
059ec3d9 | 1545 | { |
65867078 | 1546 | smtp_transport_options_block * ob = v_ob; |
059ec3d9 PH |
1547 | static uschar txt[256]; |
1548 | uschar *expciphers; | |
1549 | X509* server_cert; | |
1550 | int rc; | |
817d9f57 | 1551 | static uschar cipherbuf[256]; |
f2de3a33 | 1552 | #ifndef DISABLE_OCSP |
65867078 | 1553 | BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, |
f5d78688 | 1554 | NULL, host->name, host->address, NULL) == OK; |
44662487 JH |
1555 | BOOL request_ocsp = require_ocsp ? TRUE |
1556 | : verify_check_this_host(&ob->hosts_request_ocsp, | |
1557 | NULL, host->name, host->address, NULL) == OK; | |
f5d78688 | 1558 | #endif |
059ec3d9 | 1559 | |
65867078 JH |
1560 | rc = tls_init(&client_ctx, host, NULL, |
1561 | ob->tls_certificate, ob->tls_privatekey, | |
f2de3a33 | 1562 | #ifndef DISABLE_OCSP |
44662487 | 1563 | (void *)(long)request_ocsp, |
3f7eeb86 | 1564 | #endif |
817d9f57 | 1565 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1566 | if (rc != OK) return rc; |
1567 | ||
817d9f57 | 1568 | tls_out.certificate_verified = FALSE; |
a2ff477a | 1569 | client_verify_callback_called = FALSE; |
059ec3d9 | 1570 | |
65867078 JH |
1571 | if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", |
1572 | &expciphers)) | |
059ec3d9 PH |
1573 | return FAIL; |
1574 | ||
1575 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1576 | are separated by underscores. So that I can use either form in my tests, and | |
1577 | also for general convenience, we turn underscores into hyphens here. */ | |
1578 | ||
1579 | if (expciphers != NULL) | |
1580 | { | |
1581 | uschar *s = expciphers; | |
1582 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1583 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1584 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1585 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1586 | } |
1587 | ||
a63be306 | 1588 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
65867078 | 1589 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only |
a63be306 | 1590 | the specified host patterns if one of them is defined */ |
e51c7be2 | 1591 | |
65867078 JH |
1592 | if ((!ob->tls_verify_hosts && !ob->tls_try_verify_hosts) || |
1593 | (verify_check_host(&ob->tls_verify_hosts) == OK)) | |
a63be306 | 1594 | { |
65867078 JH |
1595 | if ((rc = setup_certs(client_ctx, ob->tls_verify_certificates, |
1596 | ob->tls_crl, host, FALSE, verify_callback_client)) != OK) | |
1597 | return rc; | |
a63be306 | 1598 | client_verify_optional = FALSE; |
e51c7be2 JH |
1599 | |
1600 | #ifdef EXPERIMENTAL_CERTNAMES | |
1601 | if (ob->tls_verify_cert_hostnames) | |
1602 | { | |
1603 | if (!expand_check(ob->tls_verify_cert_hostnames, | |
1604 | US"tls_verify_cert_hostnames", | |
1605 | &client_static_cbinfo->verify_cert_hostnames)) | |
1606 | return FAIL; | |
1607 | if (client_static_cbinfo->verify_cert_hostnames) | |
1608 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1609 | client_static_cbinfo->verify_cert_hostnames); | |
1610 | } | |
1611 | #endif | |
a63be306 | 1612 | } |
65867078 | 1613 | else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) |
a63be306 | 1614 | { |
65867078 JH |
1615 | if ((rc = setup_certs(client_ctx, ob->tls_verify_certificates, |
1616 | ob->tls_crl, host, TRUE, verify_callback_client)) != OK) | |
1617 | return rc; | |
a63be306 WB |
1618 | client_verify_optional = TRUE; |
1619 | } | |
059ec3d9 | 1620 | |
65867078 JH |
1621 | if ((client_ssl = SSL_new(client_ctx)) == NULL) |
1622 | return tls_error(US"SSL_new", host, NULL); | |
817d9f57 JH |
1623 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1624 | SSL_set_fd(client_ssl, fd); | |
1625 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 1626 | |
65867078 | 1627 | if (ob->tls_sni) |
3f0945ff | 1628 | { |
65867078 | 1629 | if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 1630 | return FAIL; |
ec4b68e5 | 1631 | if (tls_out.sni == NULL) |
2c9a0e86 PP |
1632 | { |
1633 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
1634 | } | |
ec4b68e5 | 1635 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 1636 | tls_out.sni = NULL; |
3f0945ff PP |
1637 | else |
1638 | { | |
35731706 | 1639 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
1640 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
1641 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
1642 | #else |
1643 | DEBUG(D_tls) | |
1644 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
02d9264f | 1645 | tls_out.sni); |
35731706 | 1646 | #endif |
3f0945ff PP |
1647 | } |
1648 | } | |
1649 | ||
f2de3a33 | 1650 | #ifndef DISABLE_OCSP |
f5d78688 JH |
1651 | /* Request certificate status at connection-time. If the server |
1652 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
44662487 JH |
1653 | if (request_ocsp) |
1654 | { | |
f5d78688 | 1655 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 JH |
1656 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
1657 | tls_out.ocsp = OCSP_NOT_RESP; | |
1658 | } | |
f5d78688 JH |
1659 | #endif |
1660 | ||
059ec3d9 PH |
1661 | /* There doesn't seem to be a built-in timeout on connection. */ |
1662 | ||
1663 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1664 | sigalrm_seen = FALSE; | |
65867078 | 1665 | alarm(ob->command_timeout); |
817d9f57 | 1666 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
1667 | alarm(0); |
1668 | ||
1669 | if (rc <= 0) | |
7199e1ee | 1670 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1671 | |
1672 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1673 | ||
453a6645 | 1674 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
9d1c15ef | 1675 | /*XXX server_cert is never freed... use X509_free() */ |
817d9f57 | 1676 | server_cert = SSL_get_peer_certificate (client_ssl); |
453a6645 PP |
1677 | if (server_cert) |
1678 | { | |
817d9f57 | 1679 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), |
453a6645 | 1680 | CS txt, sizeof(txt)); |
9d1c15ef | 1681 | tls_out.peerdn = txt; /*XXX a static buffer... */ |
453a6645 PP |
1682 | } |
1683 | else | |
817d9f57 | 1684 | tls_out.peerdn = NULL; |
059ec3d9 | 1685 | |
817d9f57 JH |
1686 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
1687 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 1688 | |
9d1c15ef JH |
1689 | /* Record the certificate we presented */ |
1690 | { | |
1691 | X509 * crt = SSL_get_certificate(client_ssl); | |
1692 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
1693 | } | |
1694 | ||
817d9f57 | 1695 | tls_out.active = fd; |
059ec3d9 PH |
1696 | return OK; |
1697 | } | |
1698 | ||
1699 | ||
1700 | ||
1701 | ||
1702 | ||
1703 | /************************************************* | |
1704 | * TLS version of getc * | |
1705 | *************************************************/ | |
1706 | ||
1707 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1708 | it refills the buffer via the SSL reading function. | |
1709 | ||
1710 | Arguments: none | |
1711 | Returns: the next character or EOF | |
817d9f57 JH |
1712 | |
1713 | Only used by the server-side TLS. | |
059ec3d9 PH |
1714 | */ |
1715 | ||
1716 | int | |
1717 | tls_getc(void) | |
1718 | { | |
1719 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1720 | { | |
1721 | int error; | |
1722 | int inbytes; | |
1723 | ||
817d9f57 | 1724 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 1725 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
1726 | |
1727 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
1728 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
1729 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
1730 | alarm(0); |
1731 | ||
1732 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
1733 | closed down, not that the socket itself has been closed down. Revert to | |
1734 | non-SSL handling. */ | |
1735 | ||
1736 | if (error == SSL_ERROR_ZERO_RETURN) | |
1737 | { | |
1738 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1739 | ||
1740 | receive_getc = smtp_getc; | |
1741 | receive_ungetc = smtp_ungetc; | |
1742 | receive_feof = smtp_feof; | |
1743 | receive_ferror = smtp_ferror; | |
58eb016e | 1744 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1745 | |
817d9f57 JH |
1746 | SSL_free(server_ssl); |
1747 | server_ssl = NULL; | |
1748 | tls_in.active = -1; | |
1749 | tls_in.bits = 0; | |
1750 | tls_in.cipher = NULL; | |
1751 | tls_in.peerdn = NULL; | |
1752 | tls_in.sni = NULL; | |
059ec3d9 PH |
1753 | |
1754 | return smtp_getc(); | |
1755 | } | |
1756 | ||
1757 | /* Handle genuine errors */ | |
1758 | ||
ba084640 PP |
1759 | else if (error == SSL_ERROR_SSL) |
1760 | { | |
1761 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 1762 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
1763 | ssl_xfer_error = 1; |
1764 | return EOF; | |
1765 | } | |
1766 | ||
059ec3d9 PH |
1767 | else if (error != SSL_ERROR_NONE) |
1768 | { | |
1769 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
1770 | ssl_xfer_error = 1; | |
1771 | return EOF; | |
1772 | } | |
c80c5570 | 1773 | |
80a47a2c TK |
1774 | #ifndef DISABLE_DKIM |
1775 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
1776 | #endif | |
059ec3d9 PH |
1777 | ssl_xfer_buffer_hwm = inbytes; |
1778 | ssl_xfer_buffer_lwm = 0; | |
1779 | } | |
1780 | ||
1781 | /* Something in the buffer; return next uschar */ | |
1782 | ||
1783 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1784 | } | |
1785 | ||
1786 | ||
1787 | ||
1788 | /************************************************* | |
1789 | * Read bytes from TLS channel * | |
1790 | *************************************************/ | |
1791 | ||
1792 | /* | |
1793 | Arguments: | |
1794 | buff buffer of data | |
1795 | len size of buffer | |
1796 | ||
1797 | Returns: the number of bytes read | |
1798 | -1 after a failed read | |
817d9f57 JH |
1799 | |
1800 | Only used by the client-side TLS. | |
059ec3d9 PH |
1801 | */ |
1802 | ||
1803 | int | |
389ca47a | 1804 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 1805 | { |
389ca47a | 1806 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
1807 | int inbytes; |
1808 | int error; | |
1809 | ||
389ca47a | 1810 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 1811 | buff, (unsigned int)len); |
059ec3d9 | 1812 | |
389ca47a JH |
1813 | inbytes = SSL_read(ssl, CS buff, len); |
1814 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
1815 | |
1816 | if (error == SSL_ERROR_ZERO_RETURN) | |
1817 | { | |
1818 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1819 | return -1; | |
1820 | } | |
1821 | else if (error != SSL_ERROR_NONE) | |
1822 | { | |
1823 | return -1; | |
1824 | } | |
1825 | ||
1826 | return inbytes; | |
1827 | } | |
1828 | ||
1829 | ||
1830 | ||
1831 | ||
1832 | ||
1833 | /************************************************* | |
1834 | * Write bytes down TLS channel * | |
1835 | *************************************************/ | |
1836 | ||
1837 | /* | |
1838 | Arguments: | |
817d9f57 | 1839 | is_server channel specifier |
059ec3d9 PH |
1840 | buff buffer of data |
1841 | len number of bytes | |
1842 | ||
1843 | Returns: the number of bytes after a successful write, | |
1844 | -1 after a failed write | |
817d9f57 JH |
1845 | |
1846 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1847 | */ |
1848 | ||
1849 | int | |
817d9f57 | 1850 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
1851 | { |
1852 | int outbytes; | |
1853 | int error; | |
1854 | int left = len; | |
817d9f57 | 1855 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 1856 | |
c80c5570 | 1857 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
1858 | while (left > 0) |
1859 | { | |
c80c5570 | 1860 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
1861 | outbytes = SSL_write(ssl, CS buff, left); |
1862 | error = SSL_get_error(ssl, outbytes); | |
1863 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1864 | switch (error) | |
1865 | { | |
1866 | case SSL_ERROR_SSL: | |
1867 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1868 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1869 | return -1; | |
1870 | ||
1871 | case SSL_ERROR_NONE: | |
1872 | left -= outbytes; | |
1873 | buff += outbytes; | |
1874 | break; | |
1875 | ||
1876 | case SSL_ERROR_ZERO_RETURN: | |
1877 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1878 | return -1; | |
1879 | ||
817d9f57 JH |
1880 | case SSL_ERROR_SYSCALL: |
1881 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
1882 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
1883 | strerror(errno)); | |
1884 | ||
059ec3d9 PH |
1885 | default: |
1886 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1887 | return -1; | |
1888 | } | |
1889 | } | |
1890 | return len; | |
1891 | } | |
1892 | ||
1893 | ||
1894 | ||
1895 | /************************************************* | |
1896 | * Close down a TLS session * | |
1897 | *************************************************/ | |
1898 | ||
1899 | /* This is also called from within a delivery subprocess forked from the | |
1900 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1901 | would tamper with the SSL session in the parent process). | |
1902 | ||
1903 | Arguments: TRUE if SSL_shutdown is to be called | |
1904 | Returns: nothing | |
817d9f57 JH |
1905 | |
1906 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1907 | */ |
1908 | ||
1909 | void | |
817d9f57 | 1910 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1911 | { |
817d9f57 | 1912 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 1913 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
1914 | |
1915 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
1916 | |
1917 | if (shutdown) | |
1918 | { | |
1919 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 1920 | SSL_shutdown(*sslp); |
059ec3d9 PH |
1921 | } |
1922 | ||
817d9f57 JH |
1923 | SSL_free(*sslp); |
1924 | *sslp = NULL; | |
059ec3d9 | 1925 | |
817d9f57 | 1926 | *fdp = -1; |
059ec3d9 PH |
1927 | } |
1928 | ||
36f12725 NM |
1929 | |
1930 | ||
1931 | ||
3375e053 PP |
1932 | /************************************************* |
1933 | * Let tls_require_ciphers be checked at startup * | |
1934 | *************************************************/ | |
1935 | ||
1936 | /* The tls_require_ciphers option, if set, must be something which the | |
1937 | library can parse. | |
1938 | ||
1939 | Returns: NULL on success, or error message | |
1940 | */ | |
1941 | ||
1942 | uschar * | |
1943 | tls_validate_require_cipher(void) | |
1944 | { | |
1945 | SSL_CTX *ctx; | |
1946 | uschar *s, *expciphers, *err; | |
1947 | ||
1948 | /* this duplicates from tls_init(), we need a better "init just global | |
1949 | state, for no specific purpose" singleton function of our own */ | |
1950 | ||
1951 | SSL_load_error_strings(); | |
1952 | OpenSSL_add_ssl_algorithms(); | |
1953 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
1954 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
1955 | list of available digests. */ | |
1956 | EVP_add_digest(EVP_sha256()); | |
1957 | #endif | |
1958 | ||
1959 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1960 | return NULL; | |
1961 | ||
1962 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1963 | return US"failed to expand tls_require_ciphers"; | |
1964 | ||
1965 | if (!(expciphers && *expciphers)) | |
1966 | return NULL; | |
1967 | ||
1968 | /* normalisation ripped from above */ | |
1969 | s = expciphers; | |
1970 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1971 | ||
1972 | err = NULL; | |
1973 | ||
1974 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
1975 | if (!ctx) | |
1976 | { | |
1977 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1978 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
1979 | } | |
1980 | ||
1981 | DEBUG(D_tls) | |
1982 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1983 | ||
1984 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
1985 | { | |
1986 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1987 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
1988 | } | |
1989 | ||
1990 | SSL_CTX_free(ctx); | |
1991 | ||
1992 | return err; | |
1993 | } | |
1994 | ||
1995 | ||
1996 | ||
1997 | ||
36f12725 NM |
1998 | /************************************************* |
1999 | * Report the library versions. * | |
2000 | *************************************************/ | |
2001 | ||
2002 | /* There have historically been some issues with binary compatibility in | |
2003 | OpenSSL libraries; if Exim (like many other applications) is built against | |
2004 | one version of OpenSSL but the run-time linker picks up another version, | |
2005 | it can result in serious failures, including crashing with a SIGSEGV. So | |
2006 | report the version found by the compiler and the run-time version. | |
2007 | ||
f64a1e23 PP |
2008 | Note: some OS vendors backport security fixes without changing the version |
2009 | number/string, and the version date remains unchanged. The _build_ date | |
2010 | will change, so we can more usefully assist with version diagnosis by also | |
2011 | reporting the build date. | |
2012 | ||
36f12725 NM |
2013 | Arguments: a FILE* to print the results to |
2014 | Returns: nothing | |
2015 | */ | |
2016 | ||
2017 | void | |
2018 | tls_version_report(FILE *f) | |
2019 | { | |
754a0503 | 2020 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
2021 | " Runtime: %s\n" |
2022 | " : %s\n", | |
754a0503 | 2023 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
2024 | SSLeay_version(SSLEAY_VERSION), |
2025 | SSLeay_version(SSLEAY_BUILT_ON)); | |
2026 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
2027 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
2028 | } |
2029 | ||
9e3331ea TK |
2030 | |
2031 | ||
2032 | ||
2033 | /************************************************* | |
17c76198 | 2034 | * Random number generation * |
9e3331ea TK |
2035 | *************************************************/ |
2036 | ||
2037 | /* Pseudo-random number generation. The result is not expected to be | |
2038 | cryptographically strong but not so weak that someone will shoot themselves | |
2039 | in the foot using it as a nonce in input in some email header scheme or | |
2040 | whatever weirdness they'll twist this into. The result should handle fork() | |
2041 | and avoid repeating sequences. OpenSSL handles that for us. | |
2042 | ||
2043 | Arguments: | |
2044 | max range maximum | |
2045 | Returns a random number in range [0, max-1] | |
2046 | */ | |
2047 | ||
2048 | int | |
17c76198 | 2049 | vaguely_random_number(int max) |
9e3331ea TK |
2050 | { |
2051 | unsigned int r; | |
2052 | int i, needed_len; | |
de6135a0 PP |
2053 | static pid_t pidlast = 0; |
2054 | pid_t pidnow; | |
9e3331ea TK |
2055 | uschar *p; |
2056 | uschar smallbuf[sizeof(r)]; | |
2057 | ||
2058 | if (max <= 1) | |
2059 | return 0; | |
2060 | ||
de6135a0 PP |
2061 | pidnow = getpid(); |
2062 | if (pidnow != pidlast) | |
2063 | { | |
2064 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2065 | is unique for each thread", this doesn't apparently apply across processes, | |
2066 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2067 | Fix per PostgreSQL. */ | |
2068 | if (pidlast != 0) | |
2069 | RAND_cleanup(); | |
2070 | pidlast = pidnow; | |
2071 | } | |
2072 | ||
9e3331ea TK |
2073 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
2074 | if (!RAND_status()) | |
2075 | { | |
2076 | randstuff r; | |
2077 | gettimeofday(&r.tv, NULL); | |
2078 | r.p = getpid(); | |
2079 | ||
2080 | RAND_seed((uschar *)(&r), sizeof(r)); | |
2081 | } | |
2082 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2083 | in the internal PRNG then our options are limited. We could sleep and hope | |
2084 | for entropy to come along (prayer technique) but if the system is so depleted | |
2085 | in the first place then something is likely to just keep taking it. Instead, | |
2086 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2087 | get. */ | |
2088 | ||
2089 | needed_len = sizeof(r); | |
2090 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2091 | asked for a number less than 10. */ | |
2092 | for (r = max, i = 0; r; ++i) | |
2093 | r >>= 1; | |
2094 | i = (i + 7) / 8; | |
2095 | if (i < needed_len) | |
2096 | needed_len = i; | |
2097 | ||
2098 | /* We do not care if crypto-strong */ | |
17c76198 PP |
2099 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
2100 | if (i < 0) | |
2101 | { | |
2102 | DEBUG(D_all) | |
2103 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2104 | return vaguely_random_number_fallback(max); | |
2105 | } | |
2106 | ||
9e3331ea TK |
2107 | r = 0; |
2108 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2109 | { | |
2110 | r *= 256; | |
2111 | r += *p; | |
2112 | } | |
2113 | ||
2114 | /* We don't particularly care about weighted results; if someone wants | |
2115 | smooth distribution and cares enough then they should submit a patch then. */ | |
2116 | return r % max; | |
2117 | } | |
2118 | ||
77bb000f PP |
2119 | |
2120 | ||
2121 | ||
2122 | /************************************************* | |
2123 | * OpenSSL option parse * | |
2124 | *************************************************/ | |
2125 | ||
2126 | /* Parse one option for tls_openssl_options_parse below | |
2127 | ||
2128 | Arguments: | |
2129 | name one option name | |
2130 | value place to store a value for it | |
2131 | Returns success or failure in parsing | |
2132 | */ | |
2133 | ||
2134 | struct exim_openssl_option { | |
2135 | uschar *name; | |
2136 | long value; | |
2137 | }; | |
2138 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2139 | options document which version they were introduced in. Policylet: include | |
2140 | all options unless explicitly for DTLS, let the administrator choose which | |
2141 | to apply. | |
2142 | ||
2143 | This list is current as of: | |
e2fbf4a2 PP |
2144 | ==> 1.0.1b <== |
2145 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2146 | */ | |
77bb000f PP |
2147 | static struct exim_openssl_option exim_openssl_options[] = { |
2148 | /* KEEP SORTED ALPHABETICALLY! */ | |
2149 | #ifdef SSL_OP_ALL | |
73a46702 | 2150 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2151 | #endif |
2152 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2153 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2154 | #endif |
2155 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2156 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2157 | #endif |
2158 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2159 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2160 | #endif |
2161 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2162 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2163 | #endif |
2164 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2165 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2166 | #endif |
2167 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2168 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2169 | #endif |
2170 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2171 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2172 | #endif |
2173 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2174 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2175 | #endif |
2176 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2177 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2178 | #endif |
2179 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2180 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2181 | #endif |
c80c5570 PP |
2182 | #ifdef SSL_OP_NO_COMPRESSION |
2183 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2184 | #endif | |
77bb000f | 2185 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2186 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2187 | #endif |
c0c7b2da PP |
2188 | #ifdef SSL_OP_NO_SSLv2 |
2189 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2190 | #endif | |
2191 | #ifdef SSL_OP_NO_SSLv3 | |
2192 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2193 | #endif | |
2194 | #ifdef SSL_OP_NO_TICKET | |
2195 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2196 | #endif | |
2197 | #ifdef SSL_OP_NO_TLSv1 | |
2198 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2199 | #endif | |
c80c5570 PP |
2200 | #ifdef SSL_OP_NO_TLSv1_1 |
2201 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2202 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2203 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2204 | #else | |
2205 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2206 | #endif | |
2207 | #endif | |
2208 | #ifdef SSL_OP_NO_TLSv1_2 | |
2209 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2210 | #endif | |
e2fbf4a2 PP |
2211 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG |
2212 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2213 | #endif | |
77bb000f | 2214 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2215 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2216 | #endif |
2217 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2218 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2219 | #endif |
2220 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2221 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2222 | #endif |
2223 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2224 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2225 | #endif |
2226 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2227 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2228 | #endif |
2229 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2230 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2231 | #endif |
2232 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2233 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2234 | #endif |
2235 | }; | |
2236 | static int exim_openssl_options_size = | |
2237 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2238 | ||
c80c5570 | 2239 | |
77bb000f PP |
2240 | static BOOL |
2241 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2242 | { | |
2243 | int first = 0; | |
2244 | int last = exim_openssl_options_size; | |
2245 | while (last > first) | |
2246 | { | |
2247 | int middle = (first + last)/2; | |
2248 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2249 | if (c == 0) | |
2250 | { | |
2251 | *value = exim_openssl_options[middle].value; | |
2252 | return TRUE; | |
2253 | } | |
2254 | else if (c > 0) | |
2255 | first = middle + 1; | |
2256 | else | |
2257 | last = middle; | |
2258 | } | |
2259 | return FALSE; | |
2260 | } | |
2261 | ||
2262 | ||
2263 | ||
2264 | ||
2265 | /************************************************* | |
2266 | * OpenSSL option parsing logic * | |
2267 | *************************************************/ | |
2268 | ||
2269 | /* OpenSSL has a number of compatibility options which an administrator might | |
2270 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2271 | we look like log_selector. | |
2272 | ||
2273 | Arguments: | |
2274 | option_spec the administrator-supplied string of options | |
2275 | results ptr to long storage for the options bitmap | |
2276 | Returns success or failure | |
2277 | */ | |
2278 | ||
2279 | BOOL | |
2280 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2281 | { | |
2282 | long result, item; | |
2283 | uschar *s, *end; | |
2284 | uschar keep_c; | |
2285 | BOOL adding, item_parsed; | |
2286 | ||
0e944a0d | 2287 | result = 0L; |
b1770b6e | 2288 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 2289 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
2290 | #ifdef SSL_OP_NO_SSLv2 |
2291 | result |= SSL_OP_NO_SSLv2; | |
2292 | #endif | |
77bb000f PP |
2293 | |
2294 | if (option_spec == NULL) | |
2295 | { | |
2296 | *results = result; | |
2297 | return TRUE; | |
2298 | } | |
2299 | ||
2300 | for (s=option_spec; *s != '\0'; /**/) | |
2301 | { | |
2302 | while (isspace(*s)) ++s; | |
2303 | if (*s == '\0') | |
2304 | break; | |
2305 | if (*s != '+' && *s != '-') | |
2306 | { | |
2307 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 2308 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
2309 | return FALSE; |
2310 | } | |
2311 | adding = *s++ == '+'; | |
2312 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2313 | keep_c = *end; | |
2314 | *end = '\0'; | |
2315 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2316 | if (!item_parsed) | |
2317 | { | |
0e944a0d | 2318 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
2319 | return FALSE; |
2320 | } | |
2321 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2322 | adding ? "adding" : "removing", result, item, s); | |
2323 | if (adding) | |
2324 | result |= item; | |
2325 | else | |
2326 | result &= ~item; | |
2327 | *end = keep_c; | |
2328 | s = end; | |
2329 | } | |
2330 | ||
2331 | *results = result; | |
2332 | return TRUE; | |
2333 | } | |
2334 | ||
9d1c15ef JH |
2335 | /* vi: aw ai sw=2 |
2336 | */ | |
059ec3d9 | 2337 | /* End of tls-openssl.c */ |