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