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 { | |
100 | X509_STORE *verify_store; | |
101 | } client; | |
102 | } u_ocsp; | |
3f7eeb86 | 103 | #endif |
7be682ca PP |
104 | uschar *dhparam; |
105 | /* these are cached from first expand */ | |
106 | uschar *server_cipher_list; | |
107 | /* only passed down to tls_error: */ | |
108 | host_item *host; | |
109 | } tls_ext_ctx_cb; | |
110 | ||
111 | /* should figure out a cleanup of API to handle state preserved per | |
112 | implementation, for various reasons, which can be void * in the APIs. | |
113 | For now, we hack around it. */ | |
817d9f57 JH |
114 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
115 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
116 | |
117 | static int | |
983207c1 JH |
118 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
119 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ); | |
059ec3d9 | 120 | |
3f7eeb86 | 121 | /* Callbacks */ |
3bcbbbe2 | 122 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 123 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 124 | #endif |
3f7eeb86 | 125 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 126 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
127 | #endif |
128 | ||
059ec3d9 PH |
129 | |
130 | /************************************************* | |
131 | * Handle TLS error * | |
132 | *************************************************/ | |
133 | ||
134 | /* Called from lots of places when errors occur before actually starting to do | |
135 | the TLS handshake, that is, while the session is still in clear. Always returns | |
136 | DEFER for a server and FAIL for a client so that most calls can use "return | |
137 | tls_error(...)" to do this processing and then give an appropriate return. A | |
138 | single function is used for both server and client, because it is called from | |
139 | some shared functions. | |
140 | ||
141 | Argument: | |
142 | prefix text to include in the logged error | |
143 | host NULL if setting up a server; | |
144 | the connected host if setting up a client | |
7199e1ee | 145 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
146 | |
147 | Returns: OK/DEFER/FAIL | |
148 | */ | |
149 | ||
150 | static int | |
7199e1ee | 151 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 152 | { |
7199e1ee TF |
153 | if (msg == NULL) |
154 | { | |
155 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 156 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
157 | } |
158 | ||
059ec3d9 PH |
159 | if (host == NULL) |
160 | { | |
7199e1ee | 161 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 162 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
163 | conn_info += 5; |
164 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
165 | conn_info, prefix, msg); | |
059ec3d9 PH |
166 | return DEFER; |
167 | } | |
168 | else | |
169 | { | |
170 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
7199e1ee | 171 | host->name, host->address, prefix, msg); |
059ec3d9 PH |
172 | return FAIL; |
173 | } | |
174 | } | |
175 | ||
176 | ||
177 | ||
178 | /************************************************* | |
179 | * Callback to generate RSA key * | |
180 | *************************************************/ | |
181 | ||
182 | /* | |
183 | Arguments: | |
184 | s SSL connection | |
185 | export not used | |
186 | keylength keylength | |
187 | ||
188 | Returns: pointer to generated key | |
189 | */ | |
190 | ||
191 | static RSA * | |
192 | rsa_callback(SSL *s, int export, int keylength) | |
193 | { | |
194 | RSA *rsa_key; | |
195 | export = export; /* Shut picky compilers up */ | |
196 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
197 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
198 | if (rsa_key == NULL) | |
199 | { | |
200 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
201 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
202 | ssl_errstring); | |
203 | return NULL; | |
204 | } | |
205 | return rsa_key; | |
206 | } | |
207 | ||
208 | ||
209 | ||
f5d78688 JH |
210 | /* Extreme debug |
211 | #if defined(EXPERIMENTAL_OCSP) | |
212 | void | |
213 | x509_store_dump_cert_s_names(X509_STORE * store) | |
214 | { | |
215 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
216 | int i; | |
217 | static uschar name[256]; | |
218 | ||
219 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
220 | { | |
221 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
222 | if(tmp_obj->type == X509_LU_X509) | |
223 | { | |
224 | X509 * current_cert= tmp_obj->data.x509; | |
225 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
226 | debug_printf(" %s\n", name); | |
227 | } | |
228 | } | |
229 | } | |
230 | #endif | |
231 | */ | |
232 | ||
059ec3d9 PH |
233 | |
234 | /************************************************* | |
235 | * Callback for verification * | |
236 | *************************************************/ | |
237 | ||
238 | /* The SSL library does certificate verification if set up to do so. This | |
239 | callback has the current yes/no state is in "state". If verification succeeded, | |
240 | we set up the tls_peerdn string. If verification failed, what happens depends | |
241 | on whether the client is required to present a verifiable certificate or not. | |
242 | ||
243 | If verification is optional, we change the state to yes, but still log the | |
244 | verification error. For some reason (it really would help to have proper | |
245 | documentation of OpenSSL), this callback function then gets called again, this | |
246 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
247 | value, but we must take care not to set the private verified flag on the second | |
248 | time through. | |
249 | ||
250 | Note: this function is not called if the client fails to present a certificate | |
251 | when asked. We get here only if a certificate has been received. Handling of | |
252 | optional verification for this case is done when requesting SSL to verify, by | |
253 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
254 | ||
255 | Arguments: | |
256 | state current yes/no state as 1/0 | |
257 | x509ctx certificate information. | |
a2ff477a | 258 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
259 | |
260 | Returns: 1 if verified, 0 if not | |
261 | */ | |
262 | ||
263 | static int | |
f5d78688 | 264 | verify_callback(int state, X509_STORE_CTX *x509ctx, tls_support *tlsp, BOOL *calledp, BOOL *optionalp) |
059ec3d9 PH |
265 | { |
266 | static uschar txt[256]; | |
267 | ||
268 | X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert), | |
269 | CS txt, sizeof(txt)); | |
270 | ||
271 | if (state == 0) | |
272 | { | |
273 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
274 | x509ctx->error_depth, | |
275 | X509_verify_cert_error_string(x509ctx->error), | |
276 | txt); | |
a2ff477a JH |
277 | tlsp->certificate_verified = FALSE; |
278 | *calledp = TRUE; | |
9d1c15ef JH |
279 | if (!*optionalp) |
280 | { | |
281 | tlsp->peercert = X509_dup(x509ctx->current_cert); | |
282 | return 0; /* reject */ | |
283 | } | |
059ec3d9 PH |
284 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
285 | "tls_try_verify_hosts)\n"); | |
286 | return 1; /* accept */ | |
287 | } | |
288 | ||
289 | if (x509ctx->error_depth != 0) | |
290 | { | |
291 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n", | |
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 | { | |
307 | DEBUG(D_tls) debug_printf("SSL%s peer: %s\n", | |
a2ff477a JH |
308 | *calledp ? "" : " authenticated", txt); |
309 | tlsp->peerdn = txt; | |
9d1c15ef | 310 | tlsp->peercert = X509_dup(x509ctx->current_cert); |
059ec3d9 PH |
311 | } |
312 | ||
f5d78688 JH |
313 | /*XXX JGH: this looks bogus - we set "verified" first time through, which |
314 | will be for the root CS cert (calls work down the chain). Why should it | |
315 | not be on the last call, where we're setting peerdn? | |
983207c1 JH |
316 | |
317 | To test: set up a chain anchored by a good root-CA but with a bad server cert. | |
318 | Does certificate_verified get set? | |
f5d78688 | 319 | */ |
a2ff477a JH |
320 | if (!*calledp) tlsp->certificate_verified = TRUE; |
321 | *calledp = TRUE; | |
059ec3d9 PH |
322 | |
323 | return 1; /* accept */ | |
324 | } | |
325 | ||
a2ff477a JH |
326 | static int |
327 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
328 | { | |
f5d78688 | 329 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); |
a2ff477a JH |
330 | } |
331 | ||
332 | static int | |
333 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
334 | { | |
f5d78688 | 335 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); |
a2ff477a JH |
336 | } |
337 | ||
059ec3d9 PH |
338 | |
339 | ||
340 | /************************************************* | |
341 | * Information callback * | |
342 | *************************************************/ | |
343 | ||
344 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
345 | are doing. We copy the string to the debugging output when TLS debugging has |
346 | been requested. | |
059ec3d9 PH |
347 | |
348 | Arguments: | |
349 | s the SSL connection | |
350 | where | |
351 | ret | |
352 | ||
353 | Returns: nothing | |
354 | */ | |
355 | ||
356 | static void | |
357 | info_callback(SSL *s, int where, int ret) | |
358 | { | |
359 | where = where; | |
360 | ret = ret; | |
361 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
362 | } | |
363 | ||
364 | ||
365 | ||
366 | /************************************************* | |
367 | * Initialize for DH * | |
368 | *************************************************/ | |
369 | ||
370 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
371 | ||
372 | Arguments: | |
a799883d | 373 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 374 | host connected host, if client; NULL if server |
059ec3d9 PH |
375 | |
376 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
377 | */ | |
378 | ||
379 | static BOOL | |
a799883d | 380 | init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host) |
059ec3d9 | 381 | { |
059ec3d9 PH |
382 | BIO *bio; |
383 | DH *dh; | |
384 | uschar *dhexpanded; | |
a799883d | 385 | const char *pem; |
059ec3d9 PH |
386 | |
387 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
388 | return FALSE; | |
389 | ||
a799883d | 390 | if (dhexpanded == NULL || *dhexpanded == '\0') |
059ec3d9 | 391 | { |
a799883d | 392 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
059ec3d9 | 393 | } |
a799883d | 394 | else if (dhexpanded[0] == '/') |
059ec3d9 | 395 | { |
a799883d PP |
396 | bio = BIO_new_file(CS dhexpanded, "r"); |
397 | if (bio == NULL) | |
059ec3d9 | 398 | { |
7199e1ee | 399 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
400 | host, US strerror(errno)); |
401 | return FALSE; | |
059ec3d9 | 402 | } |
a799883d PP |
403 | } |
404 | else | |
405 | { | |
406 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 407 | { |
a799883d PP |
408 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
409 | return TRUE; | |
059ec3d9 | 410 | } |
a799883d PP |
411 | |
412 | pem = std_dh_prime_named(dhexpanded); | |
413 | if (!pem) | |
414 | { | |
415 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
416 | host, US strerror(errno)); | |
417 | return FALSE; | |
418 | } | |
419 | bio = BIO_new_mem_buf(CS pem, -1); | |
420 | } | |
421 | ||
422 | dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL); | |
423 | if (dh == NULL) | |
424 | { | |
059ec3d9 | 425 | BIO_free(bio); |
a799883d PP |
426 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
427 | host, NULL); | |
428 | return FALSE; | |
429 | } | |
430 | ||
431 | /* Even if it is larger, we silently return success rather than cause things | |
432 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
433 | * debatable choice. */ | |
434 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
435 | { | |
436 | DEBUG(D_tls) | |
437 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
438 | 8*DH_size(dh), tls_dh_max_bits); | |
439 | } | |
440 | else | |
441 | { | |
442 | SSL_CTX_set_tmp_dh(sctx, dh); | |
443 | DEBUG(D_tls) | |
444 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
445 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
446 | } |
447 | ||
a799883d PP |
448 | DH_free(dh); |
449 | BIO_free(bio); | |
450 | ||
451 | return TRUE; | |
059ec3d9 PH |
452 | } |
453 | ||
454 | ||
455 | ||
456 | ||
3f7eeb86 PP |
457 | #ifdef EXPERIMENTAL_OCSP |
458 | /************************************************* | |
459 | * Load OCSP information into state * | |
460 | *************************************************/ | |
461 | ||
f5d78688 | 462 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
463 | caller has determined this is needed. Checks validity. Debugs a message |
464 | if invalid. | |
465 | ||
466 | ASSUMES: single response, for single cert. | |
467 | ||
468 | Arguments: | |
469 | sctx the SSL_CTX* to update | |
470 | cbinfo various parts of session state | |
471 | expanded the filename putatively holding an OCSP response | |
472 | ||
473 | */ | |
474 | ||
475 | static void | |
f5d78688 | 476 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 PP |
477 | { |
478 | BIO *bio; | |
479 | OCSP_RESPONSE *resp; | |
480 | OCSP_BASICRESP *basic_response; | |
481 | OCSP_SINGLERESP *single_response; | |
482 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
483 | X509_STORE *store; | |
484 | unsigned long verify_flags; | |
485 | int status, reason, i; | |
486 | ||
f5d78688 JH |
487 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
488 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 489 | { |
f5d78688 JH |
490 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
491 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
492 | } |
493 | ||
f5d78688 | 494 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); |
3f7eeb86 PP |
495 | if (!bio) |
496 | { | |
497 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 498 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
499 | return; |
500 | } | |
501 | ||
502 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
503 | BIO_free(bio); | |
504 | if (!resp) | |
505 | { | |
506 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
507 | return; | |
508 | } | |
509 | ||
510 | status = OCSP_response_status(resp); | |
511 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
512 | { | |
513 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
514 | OCSP_response_status_str(status), status); | |
f5d78688 | 515 | goto bad; |
3f7eeb86 PP |
516 | } |
517 | ||
518 | basic_response = OCSP_response_get1_basic(resp); | |
519 | if (!basic_response) | |
520 | { | |
521 | DEBUG(D_tls) | |
522 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 523 | goto bad; |
3f7eeb86 PP |
524 | } |
525 | ||
526 | store = SSL_CTX_get_cert_store(sctx); | |
527 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
528 | ||
529 | /* May need to expose ability to adjust those flags? | |
530 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
531 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
532 | ||
533 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
534 | if (i <= 0) | |
535 | { | |
536 | DEBUG(D_tls) { | |
537 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
538 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
539 | } |
540 | goto bad; | |
3f7eeb86 PP |
541 | } |
542 | ||
543 | /* Here's the simplifying assumption: there's only one response, for the | |
544 | one certificate we use, and nothing for anything else in a chain. If this | |
545 | proves false, we need to extract a cert id from our issued cert | |
546 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
547 | right cert in the stack and then calls OCSP_single_get0_status()). | |
548 | ||
549 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
550 | single_response = OCSP_resp_get0(basic_response, 0); | |
551 | if (!single_response) | |
552 | { | |
553 | DEBUG(D_tls) | |
554 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 555 | goto bad; |
3f7eeb86 PP |
556 | } |
557 | ||
558 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 559 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 560 | { |
f5d78688 JH |
561 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
562 | OCSP_cert_status_str(status), status, | |
563 | OCSP_crl_reason_str(reason), reason); | |
564 | goto bad; | |
3f7eeb86 PP |
565 | } |
566 | ||
567 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
568 | { | |
569 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 570 | goto bad; |
3f7eeb86 PP |
571 | } |
572 | ||
f5d78688 JH |
573 | supply_response: |
574 | cbinfo->u_ocsp.server.response = resp; | |
575 | return; | |
576 | ||
577 | bad: | |
578 | if (running_in_test_harness) | |
579 | { | |
580 | extern char ** environ; | |
581 | uschar ** p; | |
582 | for (p = USS environ; *p != NULL; p++) | |
583 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
584 | { | |
585 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
586 | goto supply_response; | |
587 | } | |
588 | } | |
589 | return; | |
3f7eeb86 | 590 | } |
f5d78688 | 591 | #endif /*EXPERIMENTAL_OCSP*/ |
3f7eeb86 PP |
592 | |
593 | ||
594 | ||
595 | ||
7be682ca PP |
596 | /************************************************* |
597 | * Expand key and cert file specs * | |
598 | *************************************************/ | |
599 | ||
f5d78688 | 600 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
601 | new context, if Server Name Indication was used and tls_sni was seen in |
602 | the certificate string. | |
603 | ||
604 | Arguments: | |
605 | sctx the SSL_CTX* to update | |
606 | cbinfo various parts of session state | |
607 | ||
608 | Returns: OK/DEFER/FAIL | |
609 | */ | |
610 | ||
611 | static int | |
3f7eeb86 | 612 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
613 | { |
614 | uschar *expanded; | |
615 | ||
616 | if (cbinfo->certificate == NULL) | |
617 | return OK; | |
618 | ||
d9b2312b JH |
619 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
620 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
621 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
622 | ) | |
7be682ca PP |
623 | reexpand_tls_files_for_sni = TRUE; |
624 | ||
625 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
626 | return DEFER; | |
627 | ||
628 | if (expanded != NULL) | |
629 | { | |
630 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
631 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
632 | return tls_error(string_sprintf( | |
633 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
634 | cbinfo->host, NULL); | |
635 | } | |
636 | ||
637 | if (cbinfo->privatekey != NULL && | |
638 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
639 | return DEFER; | |
640 | ||
641 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
642 | of the expansion is an empty string, ignore it also, and assume the private | |
643 | key is in the same file as the certificate. */ | |
644 | ||
645 | if (expanded != NULL && *expanded != 0) | |
646 | { | |
647 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
648 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
649 | return tls_error(string_sprintf( | |
650 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
651 | } | |
652 | ||
3f7eeb86 | 653 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 654 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) |
3f7eeb86 | 655 | { |
f5d78688 | 656 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) |
3f7eeb86 PP |
657 | return DEFER; |
658 | ||
659 | if (expanded != NULL && *expanded != 0) | |
660 | { | |
661 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f5d78688 JH |
662 | if (cbinfo->u_ocsp.server.file_expanded && |
663 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 PP |
664 | { |
665 | DEBUG(D_tls) | |
666 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
667 | } else { | |
668 | ocsp_load_response(sctx, cbinfo, expanded); | |
669 | } | |
670 | } | |
671 | } | |
672 | #endif | |
673 | ||
7be682ca PP |
674 | return OK; |
675 | } | |
676 | ||
677 | ||
678 | ||
679 | ||
680 | /************************************************* | |
681 | * Callback to handle SNI * | |
682 | *************************************************/ | |
683 | ||
684 | /* Called when acting as server during the TLS session setup if a Server Name | |
685 | Indication extension was sent by the client. | |
686 | ||
687 | API documentation is OpenSSL s_server.c implementation. | |
688 | ||
689 | Arguments: | |
690 | s SSL* of the current session | |
691 | ad unknown (part of OpenSSL API) (unused) | |
692 | arg Callback of "our" registered data | |
693 | ||
694 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
695 | */ | |
696 | ||
3bcbbbe2 | 697 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
698 | static int |
699 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
700 | { | |
701 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 702 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 703 | int rc; |
3f0945ff | 704 | int old_pool = store_pool; |
7be682ca PP |
705 | |
706 | if (!servername) | |
707 | return SSL_TLSEXT_ERR_OK; | |
708 | ||
3f0945ff | 709 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
710 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
711 | ||
712 | /* Make the extension value available for expansion */ | |
3f0945ff | 713 | store_pool = POOL_PERM; |
817d9f57 | 714 | tls_in.sni = string_copy(US servername); |
3f0945ff | 715 | store_pool = old_pool; |
7be682ca PP |
716 | |
717 | if (!reexpand_tls_files_for_sni) | |
718 | return SSL_TLSEXT_ERR_OK; | |
719 | ||
720 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
721 | not confident that memcpy wouldn't break some internal reference counting. | |
722 | Especially since there's a references struct member, which would be off. */ | |
723 | ||
817d9f57 JH |
724 | server_sni = SSL_CTX_new(SSLv23_server_method()); |
725 | if (!server_sni) | |
7be682ca PP |
726 | { |
727 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
728 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
729 | return SSL_TLSEXT_ERR_NOACK; | |
730 | } | |
731 | ||
732 | /* Not sure how many of these are actually needed, since SSL object | |
733 | already exists. Might even need this selfsame callback, for reneg? */ | |
734 | ||
817d9f57 JH |
735 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
736 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
737 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
738 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
739 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
740 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
7be682ca | 741 | if (cbinfo->server_cipher_list) |
817d9f57 | 742 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
3f7eeb86 | 743 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 744 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 745 | { |
f5d78688 | 746 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 747 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
748 | } |
749 | #endif | |
7be682ca | 750 | |
983207c1 | 751 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, verify_callback_server); |
7be682ca PP |
752 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
753 | ||
3f7eeb86 PP |
754 | /* do this after setup_certs, because this can require the certs for verifying |
755 | OCSP information. */ | |
817d9f57 | 756 | rc = tls_expand_session_files(server_sni, cbinfo); |
7be682ca PP |
757 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
758 | ||
389ca47a | 759 | rc = init_dh(server_sni, cbinfo->dhparam, NULL); |
a799883d PP |
760 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
761 | ||
7be682ca | 762 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 763 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
764 | |
765 | return SSL_TLSEXT_ERR_OK; | |
766 | } | |
3bcbbbe2 | 767 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
768 | |
769 | ||
770 | ||
771 | ||
3f7eeb86 | 772 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 773 | |
3f7eeb86 PP |
774 | /************************************************* |
775 | * Callback to handle OCSP Stapling * | |
776 | *************************************************/ | |
777 | ||
778 | /* Called when acting as server during the TLS session setup if the client | |
779 | requests OCSP information with a Certificate Status Request. | |
780 | ||
781 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
782 | project. | |
783 | ||
784 | */ | |
785 | ||
786 | static int | |
f5d78688 | 787 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
788 | { |
789 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
790 | uschar *response_der; | |
791 | int response_der_len; | |
792 | ||
f5d78688 JH |
793 | if (log_extra_selector & LX_tls_cipher) |
794 | log_write(0, LOG_MAIN, "[%s] Recieved OCSP stapling req;%s responding", | |
795 | sender_host_address, cbinfo->u_ocsp.server.response ? "":" not"); | |
796 | else | |
797 | DEBUG(D_tls) debug_printf("Received TLS status request (OCSP stapling); %s response.", | |
798 | cbinfo->u_ocsp.server.response ? "have" : "lack"); | |
799 | ||
800 | if (!cbinfo->u_ocsp.server.response) | |
3f7eeb86 PP |
801 | return SSL_TLSEXT_ERR_NOACK; |
802 | ||
803 | response_der = NULL; | |
f5d78688 | 804 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, &response_der); |
3f7eeb86 PP |
805 | if (response_der_len <= 0) |
806 | return SSL_TLSEXT_ERR_NOACK; | |
807 | ||
5e55c7a9 | 808 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
3f7eeb86 PP |
809 | return SSL_TLSEXT_ERR_OK; |
810 | } | |
811 | ||
3f7eeb86 | 812 | |
f5d78688 JH |
813 | static void |
814 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
815 | { | |
816 | BIO_printf(bp, "\t%s: ", str); | |
817 | ASN1_GENERALIZEDTIME_print(bp, time); | |
818 | BIO_puts(bp, "\n"); | |
819 | } | |
820 | ||
821 | static int | |
822 | tls_client_stapling_cb(SSL *s, void *arg) | |
823 | { | |
824 | tls_ext_ctx_cb * cbinfo = arg; | |
825 | const unsigned char * p; | |
826 | int len; | |
827 | OCSP_RESPONSE * rsp; | |
828 | OCSP_BASICRESP * bs; | |
829 | int i; | |
830 | ||
831 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
832 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
833 | if(!p) | |
834 | { | |
835 | if (log_extra_selector & LX_tls_cipher) | |
836 | log_write(0, LOG_MAIN, "Received TLS status response, null content"); | |
837 | else | |
838 | DEBUG(D_tls) debug_printf(" null\n"); | |
839 | return 0; /* This is the fail case for require-ocsp; none from server */ | |
840 | } | |
841 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) | |
842 | { | |
843 | if (log_extra_selector & LX_tls_cipher) | |
844 | log_write(0, LOG_MAIN, "Received TLS status response, parse error"); | |
845 | else | |
846 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
847 | return 0; | |
848 | } | |
849 | ||
850 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
851 | { | |
852 | if (log_extra_selector & LX_tls_cipher) | |
853 | log_write(0, LOG_MAIN, "Received TLS status response, error parsing response"); | |
854 | else | |
855 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
856 | OCSP_RESPONSE_free(rsp); | |
857 | return 0; | |
858 | } | |
859 | ||
860 | /* We'd check the nonce here if we'd put one in the request. */ | |
861 | /* However that would defeat cacheability on the server so we don't. */ | |
862 | ||
863 | ||
864 | /* This section of code reworked from OpenSSL apps source; | |
865 | The OpenSSL Project retains copyright: | |
866 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
867 | */ | |
868 | { | |
869 | BIO * bp = NULL; | |
870 | OCSP_CERTID *id; | |
871 | int status, reason; | |
872 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
873 | ||
874 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
875 | ||
876 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
877 | ||
878 | /* Use the chain that verified the server cert to verify the stapled info */ | |
879 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
880 | ||
881 | if ((i = OCSP_basic_verify(bs, NULL, cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
882 | { | |
883 | BIO_printf(bp, "OCSP response verify failure\n"); | |
884 | ERR_print_errors(bp); | |
885 | i = 0; | |
886 | goto out; | |
887 | } | |
888 | ||
889 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
890 | ||
891 | { | |
892 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
893 | OCSP_SINGLERESP * single; | |
894 | ||
895 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
896 | { | |
897 | log_write(0, LOG_MAIN, "OCSP stapling with multiple responses not handled"); | |
898 | goto out; | |
899 | } | |
900 | single = OCSP_resp_get0(bs, 0); | |
901 | status = OCSP_single_get0_status(single, &reason, &rev, &thisupd, &nextupd); | |
902 | } | |
903 | ||
904 | i = 0; | |
905 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); | |
906 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
907 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
908 | { | |
909 | DEBUG(D_tls) ERR_print_errors(bp); | |
910 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
911 | goto out; | |
912 | } | |
913 | ||
914 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", OCSP_cert_status_str(status)); | |
915 | switch(status) | |
916 | { | |
917 | case V_OCSP_CERTSTATUS_GOOD: | |
918 | i = 1; | |
919 | break; | |
920 | case V_OCSP_CERTSTATUS_REVOKED: | |
921 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", | |
922 | reason != -1 ? "; reason: " : "", reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
923 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
924 | i = 0; | |
925 | break; | |
926 | default: | |
927 | log_write(0, LOG_MAIN, "Server certificate status unknown, in OCSP stapling"); | |
928 | i = 0; | |
929 | break; | |
930 | } | |
931 | out: | |
932 | BIO_free(bp); | |
933 | } | |
934 | ||
935 | OCSP_RESPONSE_free(rsp); | |
936 | return i; | |
937 | } | |
938 | #endif /*EXPERIMENTAL_OCSP*/ | |
3f7eeb86 PP |
939 | |
940 | ||
941 | ||
059ec3d9 PH |
942 | /************************************************* |
943 | * Initialize for TLS * | |
944 | *************************************************/ | |
945 | ||
946 | /* Called from both server and client code, to do preliminary initialization of | |
947 | the library. | |
948 | ||
949 | Arguments: | |
950 | host connected host, if client; NULL if server | |
951 | dhparam DH parameter file | |
952 | certificate certificate file | |
953 | privatekey private key | |
f5d78688 | 954 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 PH |
955 | addr address if client; NULL if server (for some randomness) |
956 | ||
957 | Returns: OK/DEFER/FAIL | |
958 | */ | |
959 | ||
960 | static int | |
817d9f57 | 961 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 PP |
962 | uschar *privatekey, |
963 | #ifdef EXPERIMENTAL_OCSP | |
964 | uschar *ocsp_file, | |
965 | #endif | |
817d9f57 | 966 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 967 | { |
77bb000f | 968 | long init_options; |
7be682ca | 969 | int rc; |
77bb000f | 970 | BOOL okay; |
7be682ca PP |
971 | tls_ext_ctx_cb *cbinfo; |
972 | ||
973 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
974 | cbinfo->certificate = certificate; | |
975 | cbinfo->privatekey = privatekey; | |
3f7eeb86 | 976 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 JH |
977 | if ((cbinfo->is_server = host==NULL)) |
978 | { | |
979 | cbinfo->u_ocsp.server.file = ocsp_file; | |
980 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
981 | cbinfo->u_ocsp.server.response = NULL; | |
982 | } | |
983 | else | |
984 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 985 | #endif |
7be682ca PP |
986 | cbinfo->dhparam = dhparam; |
987 | cbinfo->host = host; | |
77bb000f | 988 | |
059ec3d9 PH |
989 | SSL_load_error_strings(); /* basic set up */ |
990 | OpenSSL_add_ssl_algorithms(); | |
991 | ||
388d6564 | 992 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 993 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
994 | list of available digests. */ |
995 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 996 | #endif |
a0475b69 | 997 | |
f0f5a555 PP |
998 | /* Create a context. |
999 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1000 | negotiation in the different methods; as far as I can tell, the only | |
1001 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1002 | when OpenSSL is built without SSLv2 support. | |
1003 | By disabling with openssl_options, we can let admins re-enable with the | |
1004 | existing knob. */ | |
059ec3d9 | 1005 | |
817d9f57 | 1006 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
1007 | SSLv23_server_method() : SSLv23_client_method()); |
1008 | ||
817d9f57 | 1009 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
1010 | |
1011 | /* It turns out that we need to seed the random number generator this early in | |
1012 | order to get the full complement of ciphers to work. It took me roughly a day | |
1013 | of work to discover this by experiment. | |
1014 | ||
1015 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1016 | there. Otherwise, we have to make something up as best we can. Double check | |
1017 | afterwards. */ | |
1018 | ||
1019 | if (!RAND_status()) | |
1020 | { | |
1021 | randstuff r; | |
9e3331ea | 1022 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1023 | r.p = getpid(); |
1024 | ||
1025 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1026 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1027 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1028 | ||
1029 | if (!RAND_status()) | |
7199e1ee | 1030 | return tls_error(US"RAND_status", host, |
5ca6d115 | 1031 | US"unable to seed random number generator"); |
059ec3d9 PH |
1032 | } |
1033 | ||
1034 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1035 | level. */ | |
1036 | ||
817d9f57 | 1037 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 1038 | |
c80c5570 | 1039 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 1040 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1041 | |
77bb000f PP |
1042 | /* Apply administrator-supplied work-arounds. |
1043 | Historically we applied just one requested option, | |
1044 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1045 | moved to an administrator-controlled list of options to specify and | |
1046 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1047 | |
77bb000f PP |
1048 | No OpenSSL version number checks: the options we accept depend upon the |
1049 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1050 | |
77bb000f PP |
1051 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
1052 | if (!okay) | |
73a46702 | 1053 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
1054 | |
1055 | if (init_options) | |
1056 | { | |
1057 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 1058 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
1059 | return tls_error(string_sprintf( |
1060 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1061 | } | |
1062 | else | |
1063 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
1064 | |
1065 | /* Initialize with DH parameters if supplied */ | |
1066 | ||
817d9f57 | 1067 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; |
059ec3d9 | 1068 | |
3f7eeb86 | 1069 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1070 | |
817d9f57 | 1071 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 1072 | if (rc != OK) return rc; |
c91535f3 | 1073 | |
7be682ca | 1074 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 1075 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
f5d78688 | 1076 | if (host == NULL) /* server */ |
3f0945ff | 1077 | { |
f5d78688 JH |
1078 | # ifdef EXPERIMENTAL_OCSP |
1079 | /* We check u_ocsp.server.file, not server.response, because we care about if | |
3f7eeb86 PP |
1080 | the option exists, not what the current expansion might be, as SNI might |
1081 | change the certificate and OCSP file in use between now and the time the | |
1082 | callback is invoked. */ | |
f5d78688 | 1083 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1084 | { |
f5d78688 | 1085 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); |
5e55c7a9 | 1086 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); |
3f7eeb86 | 1087 | } |
f5d78688 | 1088 | # endif |
3f0945ff PP |
1089 | /* We always do this, so that $tls_sni is available even if not used in |
1090 | tls_certificate */ | |
817d9f57 JH |
1091 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
1092 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 1093 | } |
f5d78688 JH |
1094 | # ifdef EXPERIMENTAL_OCSP |
1095 | else /* client */ | |
1096 | if(ocsp_file) /* wanting stapling */ | |
1097 | { | |
1098 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1099 | { | |
1100 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1101 | return FAIL; | |
1102 | } | |
1103 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1104 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1105 | } | |
1106 | # endif | |
7be682ca | 1107 | #endif |
059ec3d9 PH |
1108 | |
1109 | /* Set up the RSA callback */ | |
1110 | ||
817d9f57 | 1111 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
1112 | |
1113 | /* Finally, set the timeout, and we are done */ | |
1114 | ||
817d9f57 | 1115 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 1116 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1117 | |
817d9f57 | 1118 | *cbp = cbinfo; |
7be682ca | 1119 | |
059ec3d9 PH |
1120 | return OK; |
1121 | } | |
1122 | ||
1123 | ||
1124 | ||
1125 | ||
1126 | /************************************************* | |
1127 | * Get name of cipher in use * | |
1128 | *************************************************/ | |
1129 | ||
817d9f57 | 1130 | /* |
059ec3d9 | 1131 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1132 | buffer to use for answer |
1133 | size of buffer | |
1134 | pointer to number of bits for cipher | |
059ec3d9 PH |
1135 | Returns: nothing |
1136 | */ | |
1137 | ||
1138 | static void | |
817d9f57 | 1139 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1140 | { |
57b3a7f5 PP |
1141 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1142 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1143 | the accessor functions use const in the prototype. */ | |
1144 | const SSL_CIPHER *c; | |
d9784128 | 1145 | const uschar *ver; |
059ec3d9 | 1146 | |
d9784128 | 1147 | ver = (const uschar *)SSL_get_version(ssl); |
059ec3d9 | 1148 | |
57b3a7f5 | 1149 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1150 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1151 | |
817d9f57 JH |
1152 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1153 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1154 | |
1155 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1156 | } | |
1157 | ||
1158 | ||
1159 | ||
1160 | ||
1161 | ||
1162 | /************************************************* | |
1163 | * Set up for verifying certificates * | |
1164 | *************************************************/ | |
1165 | ||
1166 | /* Called by both client and server startup | |
1167 | ||
1168 | Arguments: | |
7be682ca | 1169 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1170 | certs certs file or NULL |
1171 | crl CRL file or NULL | |
1172 | host NULL in a server; the remote host in a client | |
1173 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1174 | otherwise passed as FALSE | |
983207c1 | 1175 | cert_vfy_cb Callback function for certificate verification |
059ec3d9 PH |
1176 | |
1177 | Returns: OK/DEFER/FAIL | |
1178 | */ | |
1179 | ||
1180 | static int | |
983207c1 JH |
1181 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
1182 | int (*cert_vfy_cb)(int, X509_STORE_CTX *) ) | |
059ec3d9 PH |
1183 | { |
1184 | uschar *expcerts, *expcrl; | |
1185 | ||
1186 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1187 | return DEFER; | |
1188 | ||
26e72755 | 1189 | if (expcerts != NULL && *expcerts != '\0') |
059ec3d9 PH |
1190 | { |
1191 | struct stat statbuf; | |
7be682ca | 1192 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
7199e1ee | 1193 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
1194 | |
1195 | if (Ustat(expcerts, &statbuf) < 0) | |
1196 | { | |
1197 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1198 | "failed to stat %s for certificates", expcerts); | |
1199 | return DEFER; | |
1200 | } | |
1201 | else | |
1202 | { | |
1203 | uschar *file, *dir; | |
1204 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1205 | { file = NULL; dir = expcerts; } | |
1206 | else | |
1207 | { file = expcerts; dir = NULL; } | |
1208 | ||
1209 | /* If a certificate file is empty, the next function fails with an | |
1210 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1211 | certificates are recognized, but the error message is still misleading (it | |
1212 | says no certificate was supplied.) But this is better. */ | |
1213 | ||
1214 | if ((file == NULL || statbuf.st_size > 0) && | |
7be682ca | 1215 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) |
7199e1ee | 1216 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 PH |
1217 | |
1218 | if (file != NULL) | |
1219 | { | |
7be682ca | 1220 | SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); |
059ec3d9 PH |
1221 | } |
1222 | } | |
1223 | ||
1224 | /* Handle a certificate revocation list. */ | |
1225 | ||
1226 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1227 | ||
8b417f2c PH |
1228 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1229 | * merely reformatted it into the Exim code style.) | |
1230 | ||
1231 | * "From here I changed the code to add support for multiple crl's | |
1232 | * in pem format in one file or to support hashed directory entries in | |
1233 | * pem format instead of a file. This method now uses the library function | |
1234 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1235 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1236 | * itself in the verify callback." */ | |
1237 | ||
059ec3d9 PH |
1238 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1239 | if (expcrl != NULL && *expcrl != 0) | |
1240 | { | |
8b417f2c PH |
1241 | struct stat statbufcrl; |
1242 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1243 | { | |
1244 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1245 | "failed to stat %s for certificates revocation lists", expcrl); | |
1246 | return DEFER; | |
1247 | } | |
1248 | else | |
059ec3d9 | 1249 | { |
8b417f2c PH |
1250 | /* is it a file or directory? */ |
1251 | uschar *file, *dir; | |
7be682ca | 1252 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1253 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1254 | { |
8b417f2c PH |
1255 | file = NULL; |
1256 | dir = expcrl; | |
1257 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1258 | } |
1259 | else | |
1260 | { | |
8b417f2c PH |
1261 | file = expcrl; |
1262 | dir = NULL; | |
1263 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1264 | } |
8b417f2c | 1265 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1266 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1267 | |
1268 | /* setting the flags to check against the complete crl chain */ | |
1269 | ||
1270 | X509_STORE_set_flags(cvstore, | |
1271 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1272 | } |
059ec3d9 PH |
1273 | } |
1274 | ||
1275 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1276 | ||
1277 | /* If verification is optional, don't fail if no certificate */ | |
1278 | ||
7be682ca | 1279 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1280 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 1281 | cert_vfy_cb); |
059ec3d9 PH |
1282 | } |
1283 | ||
1284 | return OK; | |
1285 | } | |
1286 | ||
1287 | ||
1288 | ||
1289 | /************************************************* | |
1290 | * Start a TLS session in a server * | |
1291 | *************************************************/ | |
1292 | ||
1293 | /* This is called when Exim is running as a server, after having received | |
1294 | the STARTTLS command. It must respond to that command, and then negotiate | |
1295 | a TLS session. | |
1296 | ||
1297 | Arguments: | |
1298 | require_ciphers allowed ciphers | |
1299 | ||
1300 | Returns: OK on success | |
1301 | DEFER for errors before the start of the negotiation | |
1302 | FAIL for errors during the negotation; the server can't | |
1303 | continue running. | |
1304 | */ | |
1305 | ||
1306 | int | |
17c76198 | 1307 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1308 | { |
1309 | int rc; | |
1310 | uschar *expciphers; | |
7be682ca | 1311 | tls_ext_ctx_cb *cbinfo; |
817d9f57 | 1312 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1313 | |
1314 | /* Check for previous activation */ | |
1315 | ||
817d9f57 | 1316 | if (tls_in.active >= 0) |
059ec3d9 | 1317 | { |
5ca6d115 | 1318 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1319 | smtp_printf("554 Already in TLS\r\n"); |
1320 | return FAIL; | |
1321 | } | |
1322 | ||
1323 | /* Initialize the SSL library. If it fails, it will already have logged | |
1324 | the error. */ | |
1325 | ||
817d9f57 | 1326 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
3f7eeb86 PP |
1327 | #ifdef EXPERIMENTAL_OCSP |
1328 | tls_ocsp_file, | |
1329 | #endif | |
817d9f57 | 1330 | NULL, &server_static_cbinfo); |
059ec3d9 | 1331 | if (rc != OK) return rc; |
817d9f57 | 1332 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1333 | |
1334 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1335 | return FAIL; | |
1336 | ||
1337 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1338 | were historically separated by underscores. So that I can use either form in my |
1339 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1340 | */ | |
059ec3d9 PH |
1341 | |
1342 | if (expciphers != NULL) | |
1343 | { | |
1344 | uschar *s = expciphers; | |
1345 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1346 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1347 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1348 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1349 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1350 | } |
1351 | ||
1352 | /* If this is a host for which certificate verification is mandatory or | |
1353 | optional, set up appropriately. */ | |
1354 | ||
817d9f57 | 1355 | tls_in.certificate_verified = FALSE; |
a2ff477a | 1356 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1357 | |
1358 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1359 | { | |
983207c1 JH |
1360 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1361 | FALSE, verify_callback_server); | |
059ec3d9 | 1362 | if (rc != OK) return rc; |
a2ff477a | 1363 | server_verify_optional = FALSE; |
059ec3d9 PH |
1364 | } |
1365 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1366 | { | |
983207c1 JH |
1367 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
1368 | TRUE, verify_callback_server); | |
059ec3d9 | 1369 | if (rc != OK) return rc; |
a2ff477a | 1370 | server_verify_optional = TRUE; |
059ec3d9 PH |
1371 | } |
1372 | ||
1373 | /* Prepare for new connection */ | |
1374 | ||
817d9f57 | 1375 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1376 | |
1377 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1378 | * | |
1379 | * With the SSL_clear(), we get strange interoperability bugs with | |
1380 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1381 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1382 | * | |
1383 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1384 | * session shutdown. In this case, we have a brand new object and there's no | |
1385 | * obvious reason to immediately clear it. I'm guessing that this was | |
1386 | * originally added because of incomplete initialisation which the clear fixed, | |
1387 | * in some historic release. | |
1388 | */ | |
059ec3d9 PH |
1389 | |
1390 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1391 | on connection, where outputting anything now upsets the clients and tends to | |
1392 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1393 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1394 | mode, the fflush() happens when smtp_getc() is called. */ | |
1395 | ||
817d9f57 JH |
1396 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1397 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1398 | { |
1399 | smtp_printf("220 TLS go ahead\r\n"); | |
1400 | fflush(smtp_out); | |
1401 | } | |
1402 | ||
1403 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1404 | that the OpenSSL library doesn't. */ | |
1405 | ||
817d9f57 JH |
1406 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1407 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1408 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1409 | |
1410 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1411 | ||
1412 | sigalrm_seen = FALSE; | |
1413 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1414 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1415 | alarm(0); |
1416 | ||
1417 | if (rc <= 0) | |
1418 | { | |
7199e1ee | 1419 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1420 | if (ERR_get_error() == 0) |
1421 | log_write(0, LOG_MAIN, | |
a053d125 | 1422 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1423 | return FAIL; |
1424 | } | |
1425 | ||
1426 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1427 | ||
1428 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1429 | and initialize things. */ | |
1430 | ||
817d9f57 JH |
1431 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1432 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1433 | |
1434 | DEBUG(D_tls) | |
1435 | { | |
1436 | uschar buf[2048]; | |
817d9f57 | 1437 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1438 | debug_printf("Shared ciphers: %s\n", buf); |
1439 | } | |
1440 | ||
9d1c15ef JH |
1441 | /* Record the certificate we presented */ |
1442 | { | |
1443 | X509 * crt = SSL_get_certificate(server_ssl); | |
1444 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
1445 | } | |
059ec3d9 | 1446 | |
817d9f57 JH |
1447 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1448 | Client-side (tls_out) reads (seem to?) go via | |
1449 | smtp_read_response()/ip_recv(). | |
1450 | Hence no need to duplicate for _in and _out. | |
1451 | */ | |
059ec3d9 PH |
1452 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1453 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1454 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1455 | ||
1456 | receive_getc = tls_getc; | |
1457 | receive_ungetc = tls_ungetc; | |
1458 | receive_feof = tls_feof; | |
1459 | receive_ferror = tls_ferror; | |
58eb016e | 1460 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1461 | |
817d9f57 | 1462 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1463 | return OK; |
1464 | } | |
1465 | ||
1466 | ||
1467 | ||
1468 | ||
1469 | ||
1470 | /************************************************* | |
1471 | * Start a TLS session in a client * | |
1472 | *************************************************/ | |
1473 | ||
1474 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1475 | ||
1476 | Argument: | |
1477 | fd the fd of the connection | |
1478 | host connected host (for messages) | |
83da1223 | 1479 | addr the first address |
059ec3d9 PH |
1480 | certificate certificate file |
1481 | privatekey private key file | |
3f0945ff | 1482 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1483 | verify_certs file for certificate verify |
1484 | crl file containing CRL | |
1485 | require_ciphers list of allowed ciphers | |
54c90be1 PP |
1486 | dh_min_bits minimum number of bits acceptable in server's DH prime |
1487 | (unused in OpenSSL) | |
83da1223 | 1488 | timeout startup timeout |
a63be306 WB |
1489 | verify_hosts mandatory client verification |
1490 | try_verify_hosts optional client verification | |
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, |
3f0945ff PP |
1499 | uschar *certificate, uschar *privatekey, uschar *sni, |
1500 | uschar *verify_certs, uschar *crl, | |
f5d78688 JH |
1501 | uschar *require_ciphers, |
1502 | #ifdef EXPERIMENTAL_OCSP | |
1503 | uschar *hosts_require_ocsp, | |
1504 | #endif | |
a63be306 WB |
1505 | int dh_min_bits ARG_UNUSED, int timeout, |
1506 | uschar *verify_hosts, uschar *try_verify_hosts) | |
059ec3d9 PH |
1507 | { |
1508 | static uschar txt[256]; | |
1509 | uschar *expciphers; | |
1510 | X509* server_cert; | |
1511 | int rc; | |
817d9f57 | 1512 | static uschar cipherbuf[256]; |
f5d78688 JH |
1513 | #ifdef EXPERIMENTAL_OCSP |
1514 | BOOL require_ocsp = verify_check_this_host(&hosts_require_ocsp, | |
1515 | NULL, host->name, host->address, NULL) == OK; | |
1516 | #endif | |
059ec3d9 | 1517 | |
f5d78688 | 1518 | rc = tls_init(&client_ctx, host, NULL, certificate, privatekey, |
3f7eeb86 | 1519 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 1520 | require_ocsp ? US"" : NULL, |
3f7eeb86 | 1521 | #endif |
817d9f57 | 1522 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1523 | if (rc != OK) return rc; |
1524 | ||
817d9f57 | 1525 | tls_out.certificate_verified = FALSE; |
a2ff477a | 1526 | client_verify_callback_called = FALSE; |
059ec3d9 PH |
1527 | |
1528 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1529 | return FAIL; | |
1530 | ||
1531 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1532 | are separated by underscores. So that I can use either form in my tests, and | |
1533 | also for general convenience, we turn underscores into hyphens here. */ | |
1534 | ||
1535 | if (expciphers != NULL) | |
1536 | { | |
1537 | uschar *s = expciphers; | |
1538 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1539 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1540 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1541 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1542 | } |
1543 | ||
a63be306 WB |
1544 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
1545 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only | |
1546 | the specified host patterns if one of them is defined */ | |
1547 | if (((verify_hosts == NULL) && (try_verify_hosts == NULL)) || | |
1548 | (verify_check_host(&verify_hosts) == OK)) | |
1549 | { | |
1550 | rc = setup_certs(client_ctx, verify_certs, crl, host, FALSE, verify_callback_client); | |
1551 | if (rc != OK) return rc; | |
1552 | client_verify_optional = FALSE; | |
1553 | } | |
1554 | else if (verify_check_host(&try_verify_hosts) == OK) | |
1555 | { | |
1556 | rc = setup_certs(client_ctx, verify_certs, crl, host, TRUE, verify_callback_client); | |
1557 | if (rc != OK) return rc; | |
1558 | client_verify_optional = TRUE; | |
1559 | } | |
059ec3d9 | 1560 | |
817d9f57 JH |
1561 | if ((client_ssl = SSL_new(client_ctx)) == NULL) return tls_error(US"SSL_new", host, NULL); |
1562 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); | |
1563 | SSL_set_fd(client_ssl, fd); | |
1564 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 1565 | |
3f0945ff PP |
1566 | if (sni) |
1567 | { | |
817d9f57 | 1568 | if (!expand_check(sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 1569 | return FAIL; |
ec4b68e5 | 1570 | if (tls_out.sni == NULL) |
2c9a0e86 PP |
1571 | { |
1572 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
1573 | } | |
ec4b68e5 | 1574 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 1575 | tls_out.sni = NULL; |
3f0945ff PP |
1576 | else |
1577 | { | |
35731706 | 1578 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
1579 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
1580 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
1581 | #else |
1582 | DEBUG(D_tls) | |
1583 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
02d9264f | 1584 | tls_out.sni); |
35731706 | 1585 | #endif |
3f0945ff PP |
1586 | } |
1587 | } | |
1588 | ||
f5d78688 JH |
1589 | #ifdef EXPERIMENTAL_OCSP |
1590 | /* Request certificate status at connection-time. If the server | |
1591 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
1592 | if (require_ocsp) | |
1593 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); | |
1594 | #endif | |
1595 | ||
059ec3d9 PH |
1596 | /* There doesn't seem to be a built-in timeout on connection. */ |
1597 | ||
1598 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1599 | sigalrm_seen = FALSE; | |
1600 | alarm(timeout); | |
817d9f57 | 1601 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
1602 | alarm(0); |
1603 | ||
1604 | if (rc <= 0) | |
7199e1ee | 1605 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1606 | |
1607 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1608 | ||
453a6645 | 1609 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
9d1c15ef | 1610 | /*XXX server_cert is never freed... use X509_free() */ |
817d9f57 | 1611 | server_cert = SSL_get_peer_certificate (client_ssl); |
453a6645 PP |
1612 | if (server_cert) |
1613 | { | |
817d9f57 | 1614 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), |
453a6645 | 1615 | CS txt, sizeof(txt)); |
9d1c15ef | 1616 | tls_out.peerdn = txt; /*XXX a static buffer... */ |
453a6645 PP |
1617 | } |
1618 | else | |
817d9f57 | 1619 | tls_out.peerdn = NULL; |
059ec3d9 | 1620 | |
817d9f57 JH |
1621 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
1622 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 1623 | |
9d1c15ef JH |
1624 | /* Record the certificate we presented */ |
1625 | { | |
1626 | X509 * crt = SSL_get_certificate(client_ssl); | |
1627 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
1628 | } | |
1629 | ||
817d9f57 | 1630 | tls_out.active = fd; |
059ec3d9 PH |
1631 | return OK; |
1632 | } | |
1633 | ||
1634 | ||
1635 | ||
1636 | ||
1637 | ||
1638 | /************************************************* | |
1639 | * TLS version of getc * | |
1640 | *************************************************/ | |
1641 | ||
1642 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1643 | it refills the buffer via the SSL reading function. | |
1644 | ||
1645 | Arguments: none | |
1646 | Returns: the next character or EOF | |
817d9f57 JH |
1647 | |
1648 | Only used by the server-side TLS. | |
059ec3d9 PH |
1649 | */ |
1650 | ||
1651 | int | |
1652 | tls_getc(void) | |
1653 | { | |
1654 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1655 | { | |
1656 | int error; | |
1657 | int inbytes; | |
1658 | ||
817d9f57 | 1659 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 1660 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
1661 | |
1662 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
1663 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
1664 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
1665 | alarm(0); |
1666 | ||
1667 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
1668 | closed down, not that the socket itself has been closed down. Revert to | |
1669 | non-SSL handling. */ | |
1670 | ||
1671 | if (error == SSL_ERROR_ZERO_RETURN) | |
1672 | { | |
1673 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1674 | ||
1675 | receive_getc = smtp_getc; | |
1676 | receive_ungetc = smtp_ungetc; | |
1677 | receive_feof = smtp_feof; | |
1678 | receive_ferror = smtp_ferror; | |
58eb016e | 1679 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1680 | |
817d9f57 JH |
1681 | SSL_free(server_ssl); |
1682 | server_ssl = NULL; | |
1683 | tls_in.active = -1; | |
1684 | tls_in.bits = 0; | |
1685 | tls_in.cipher = NULL; | |
1686 | tls_in.peerdn = NULL; | |
1687 | tls_in.sni = NULL; | |
059ec3d9 PH |
1688 | |
1689 | return smtp_getc(); | |
1690 | } | |
1691 | ||
1692 | /* Handle genuine errors */ | |
1693 | ||
ba084640 PP |
1694 | else if (error == SSL_ERROR_SSL) |
1695 | { | |
1696 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 1697 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
1698 | ssl_xfer_error = 1; |
1699 | return EOF; | |
1700 | } | |
1701 | ||
059ec3d9 PH |
1702 | else if (error != SSL_ERROR_NONE) |
1703 | { | |
1704 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
1705 | ssl_xfer_error = 1; | |
1706 | return EOF; | |
1707 | } | |
c80c5570 | 1708 | |
80a47a2c TK |
1709 | #ifndef DISABLE_DKIM |
1710 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
1711 | #endif | |
059ec3d9 PH |
1712 | ssl_xfer_buffer_hwm = inbytes; |
1713 | ssl_xfer_buffer_lwm = 0; | |
1714 | } | |
1715 | ||
1716 | /* Something in the buffer; return next uschar */ | |
1717 | ||
1718 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1719 | } | |
1720 | ||
1721 | ||
1722 | ||
1723 | /************************************************* | |
1724 | * Read bytes from TLS channel * | |
1725 | *************************************************/ | |
1726 | ||
1727 | /* | |
1728 | Arguments: | |
1729 | buff buffer of data | |
1730 | len size of buffer | |
1731 | ||
1732 | Returns: the number of bytes read | |
1733 | -1 after a failed read | |
817d9f57 JH |
1734 | |
1735 | Only used by the client-side TLS. | |
059ec3d9 PH |
1736 | */ |
1737 | ||
1738 | int | |
389ca47a | 1739 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 1740 | { |
389ca47a | 1741 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
1742 | int inbytes; |
1743 | int error; | |
1744 | ||
389ca47a | 1745 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 1746 | buff, (unsigned int)len); |
059ec3d9 | 1747 | |
389ca47a JH |
1748 | inbytes = SSL_read(ssl, CS buff, len); |
1749 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
1750 | |
1751 | if (error == SSL_ERROR_ZERO_RETURN) | |
1752 | { | |
1753 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1754 | return -1; | |
1755 | } | |
1756 | else if (error != SSL_ERROR_NONE) | |
1757 | { | |
1758 | return -1; | |
1759 | } | |
1760 | ||
1761 | return inbytes; | |
1762 | } | |
1763 | ||
1764 | ||
1765 | ||
1766 | ||
1767 | ||
1768 | /************************************************* | |
1769 | * Write bytes down TLS channel * | |
1770 | *************************************************/ | |
1771 | ||
1772 | /* | |
1773 | Arguments: | |
817d9f57 | 1774 | is_server channel specifier |
059ec3d9 PH |
1775 | buff buffer of data |
1776 | len number of bytes | |
1777 | ||
1778 | Returns: the number of bytes after a successful write, | |
1779 | -1 after a failed write | |
817d9f57 JH |
1780 | |
1781 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1782 | */ |
1783 | ||
1784 | int | |
817d9f57 | 1785 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
1786 | { |
1787 | int outbytes; | |
1788 | int error; | |
1789 | int left = len; | |
817d9f57 | 1790 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 1791 | |
c80c5570 | 1792 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
1793 | while (left > 0) |
1794 | { | |
c80c5570 | 1795 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
1796 | outbytes = SSL_write(ssl, CS buff, left); |
1797 | error = SSL_get_error(ssl, outbytes); | |
1798 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1799 | switch (error) | |
1800 | { | |
1801 | case SSL_ERROR_SSL: | |
1802 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1803 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1804 | return -1; | |
1805 | ||
1806 | case SSL_ERROR_NONE: | |
1807 | left -= outbytes; | |
1808 | buff += outbytes; | |
1809 | break; | |
1810 | ||
1811 | case SSL_ERROR_ZERO_RETURN: | |
1812 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1813 | return -1; | |
1814 | ||
817d9f57 JH |
1815 | case SSL_ERROR_SYSCALL: |
1816 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
1817 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
1818 | strerror(errno)); | |
1819 | ||
059ec3d9 PH |
1820 | default: |
1821 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1822 | return -1; | |
1823 | } | |
1824 | } | |
1825 | return len; | |
1826 | } | |
1827 | ||
1828 | ||
1829 | ||
1830 | /************************************************* | |
1831 | * Close down a TLS session * | |
1832 | *************************************************/ | |
1833 | ||
1834 | /* This is also called from within a delivery subprocess forked from the | |
1835 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1836 | would tamper with the SSL session in the parent process). | |
1837 | ||
1838 | Arguments: TRUE if SSL_shutdown is to be called | |
1839 | Returns: nothing | |
817d9f57 JH |
1840 | |
1841 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1842 | */ |
1843 | ||
1844 | void | |
817d9f57 | 1845 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1846 | { |
817d9f57 | 1847 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 1848 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
1849 | |
1850 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
1851 | |
1852 | if (shutdown) | |
1853 | { | |
1854 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 1855 | SSL_shutdown(*sslp); |
059ec3d9 PH |
1856 | } |
1857 | ||
817d9f57 JH |
1858 | SSL_free(*sslp); |
1859 | *sslp = NULL; | |
059ec3d9 | 1860 | |
817d9f57 | 1861 | *fdp = -1; |
059ec3d9 PH |
1862 | } |
1863 | ||
36f12725 NM |
1864 | |
1865 | ||
1866 | ||
3375e053 PP |
1867 | /************************************************* |
1868 | * Let tls_require_ciphers be checked at startup * | |
1869 | *************************************************/ | |
1870 | ||
1871 | /* The tls_require_ciphers option, if set, must be something which the | |
1872 | library can parse. | |
1873 | ||
1874 | Returns: NULL on success, or error message | |
1875 | */ | |
1876 | ||
1877 | uschar * | |
1878 | tls_validate_require_cipher(void) | |
1879 | { | |
1880 | SSL_CTX *ctx; | |
1881 | uschar *s, *expciphers, *err; | |
1882 | ||
1883 | /* this duplicates from tls_init(), we need a better "init just global | |
1884 | state, for no specific purpose" singleton function of our own */ | |
1885 | ||
1886 | SSL_load_error_strings(); | |
1887 | OpenSSL_add_ssl_algorithms(); | |
1888 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
1889 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
1890 | list of available digests. */ | |
1891 | EVP_add_digest(EVP_sha256()); | |
1892 | #endif | |
1893 | ||
1894 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1895 | return NULL; | |
1896 | ||
1897 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1898 | return US"failed to expand tls_require_ciphers"; | |
1899 | ||
1900 | if (!(expciphers && *expciphers)) | |
1901 | return NULL; | |
1902 | ||
1903 | /* normalisation ripped from above */ | |
1904 | s = expciphers; | |
1905 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1906 | ||
1907 | err = NULL; | |
1908 | ||
1909 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
1910 | if (!ctx) | |
1911 | { | |
1912 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1913 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
1914 | } | |
1915 | ||
1916 | DEBUG(D_tls) | |
1917 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1918 | ||
1919 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
1920 | { | |
1921 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1922 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
1923 | } | |
1924 | ||
1925 | SSL_CTX_free(ctx); | |
1926 | ||
1927 | return err; | |
1928 | } | |
1929 | ||
1930 | ||
1931 | ||
1932 | ||
36f12725 NM |
1933 | /************************************************* |
1934 | * Report the library versions. * | |
1935 | *************************************************/ | |
1936 | ||
1937 | /* There have historically been some issues with binary compatibility in | |
1938 | OpenSSL libraries; if Exim (like many other applications) is built against | |
1939 | one version of OpenSSL but the run-time linker picks up another version, | |
1940 | it can result in serious failures, including crashing with a SIGSEGV. So | |
1941 | report the version found by the compiler and the run-time version. | |
1942 | ||
f64a1e23 PP |
1943 | Note: some OS vendors backport security fixes without changing the version |
1944 | number/string, and the version date remains unchanged. The _build_ date | |
1945 | will change, so we can more usefully assist with version diagnosis by also | |
1946 | reporting the build date. | |
1947 | ||
36f12725 NM |
1948 | Arguments: a FILE* to print the results to |
1949 | Returns: nothing | |
1950 | */ | |
1951 | ||
1952 | void | |
1953 | tls_version_report(FILE *f) | |
1954 | { | |
754a0503 | 1955 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
1956 | " Runtime: %s\n" |
1957 | " : %s\n", | |
754a0503 | 1958 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
1959 | SSLeay_version(SSLEAY_VERSION), |
1960 | SSLeay_version(SSLEAY_BUILT_ON)); | |
1961 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
1962 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
1963 | } |
1964 | ||
9e3331ea TK |
1965 | |
1966 | ||
1967 | ||
1968 | /************************************************* | |
17c76198 | 1969 | * Random number generation * |
9e3331ea TK |
1970 | *************************************************/ |
1971 | ||
1972 | /* Pseudo-random number generation. The result is not expected to be | |
1973 | cryptographically strong but not so weak that someone will shoot themselves | |
1974 | in the foot using it as a nonce in input in some email header scheme or | |
1975 | whatever weirdness they'll twist this into. The result should handle fork() | |
1976 | and avoid repeating sequences. OpenSSL handles that for us. | |
1977 | ||
1978 | Arguments: | |
1979 | max range maximum | |
1980 | Returns a random number in range [0, max-1] | |
1981 | */ | |
1982 | ||
1983 | int | |
17c76198 | 1984 | vaguely_random_number(int max) |
9e3331ea TK |
1985 | { |
1986 | unsigned int r; | |
1987 | int i, needed_len; | |
de6135a0 PP |
1988 | static pid_t pidlast = 0; |
1989 | pid_t pidnow; | |
9e3331ea TK |
1990 | uschar *p; |
1991 | uschar smallbuf[sizeof(r)]; | |
1992 | ||
1993 | if (max <= 1) | |
1994 | return 0; | |
1995 | ||
de6135a0 PP |
1996 | pidnow = getpid(); |
1997 | if (pidnow != pidlast) | |
1998 | { | |
1999 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2000 | is unique for each thread", this doesn't apparently apply across processes, | |
2001 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2002 | Fix per PostgreSQL. */ | |
2003 | if (pidlast != 0) | |
2004 | RAND_cleanup(); | |
2005 | pidlast = pidnow; | |
2006 | } | |
2007 | ||
9e3331ea TK |
2008 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
2009 | if (!RAND_status()) | |
2010 | { | |
2011 | randstuff r; | |
2012 | gettimeofday(&r.tv, NULL); | |
2013 | r.p = getpid(); | |
2014 | ||
2015 | RAND_seed((uschar *)(&r), sizeof(r)); | |
2016 | } | |
2017 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2018 | in the internal PRNG then our options are limited. We could sleep and hope | |
2019 | for entropy to come along (prayer technique) but if the system is so depleted | |
2020 | in the first place then something is likely to just keep taking it. Instead, | |
2021 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2022 | get. */ | |
2023 | ||
2024 | needed_len = sizeof(r); | |
2025 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2026 | asked for a number less than 10. */ | |
2027 | for (r = max, i = 0; r; ++i) | |
2028 | r >>= 1; | |
2029 | i = (i + 7) / 8; | |
2030 | if (i < needed_len) | |
2031 | needed_len = i; | |
2032 | ||
2033 | /* We do not care if crypto-strong */ | |
17c76198 PP |
2034 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
2035 | if (i < 0) | |
2036 | { | |
2037 | DEBUG(D_all) | |
2038 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2039 | return vaguely_random_number_fallback(max); | |
2040 | } | |
2041 | ||
9e3331ea TK |
2042 | r = 0; |
2043 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2044 | { | |
2045 | r *= 256; | |
2046 | r += *p; | |
2047 | } | |
2048 | ||
2049 | /* We don't particularly care about weighted results; if someone wants | |
2050 | smooth distribution and cares enough then they should submit a patch then. */ | |
2051 | return r % max; | |
2052 | } | |
2053 | ||
77bb000f PP |
2054 | |
2055 | ||
2056 | ||
2057 | /************************************************* | |
2058 | * OpenSSL option parse * | |
2059 | *************************************************/ | |
2060 | ||
2061 | /* Parse one option for tls_openssl_options_parse below | |
2062 | ||
2063 | Arguments: | |
2064 | name one option name | |
2065 | value place to store a value for it | |
2066 | Returns success or failure in parsing | |
2067 | */ | |
2068 | ||
2069 | struct exim_openssl_option { | |
2070 | uschar *name; | |
2071 | long value; | |
2072 | }; | |
2073 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2074 | options document which version they were introduced in. Policylet: include | |
2075 | all options unless explicitly for DTLS, let the administrator choose which | |
2076 | to apply. | |
2077 | ||
2078 | This list is current as of: | |
e2fbf4a2 PP |
2079 | ==> 1.0.1b <== |
2080 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2081 | */ | |
77bb000f PP |
2082 | static struct exim_openssl_option exim_openssl_options[] = { |
2083 | /* KEEP SORTED ALPHABETICALLY! */ | |
2084 | #ifdef SSL_OP_ALL | |
73a46702 | 2085 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2086 | #endif |
2087 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2088 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2089 | #endif |
2090 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2091 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2092 | #endif |
2093 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2094 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2095 | #endif |
2096 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2097 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2098 | #endif |
2099 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2100 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2101 | #endif |
2102 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2103 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2104 | #endif |
2105 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2106 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2107 | #endif |
2108 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2109 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2110 | #endif |
2111 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2112 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2113 | #endif |
2114 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2115 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2116 | #endif |
c80c5570 PP |
2117 | #ifdef SSL_OP_NO_COMPRESSION |
2118 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2119 | #endif | |
77bb000f | 2120 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2121 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2122 | #endif |
c0c7b2da PP |
2123 | #ifdef SSL_OP_NO_SSLv2 |
2124 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2125 | #endif | |
2126 | #ifdef SSL_OP_NO_SSLv3 | |
2127 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2128 | #endif | |
2129 | #ifdef SSL_OP_NO_TICKET | |
2130 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2131 | #endif | |
2132 | #ifdef SSL_OP_NO_TLSv1 | |
2133 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2134 | #endif | |
c80c5570 PP |
2135 | #ifdef SSL_OP_NO_TLSv1_1 |
2136 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2137 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2138 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2139 | #else | |
2140 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2141 | #endif | |
2142 | #endif | |
2143 | #ifdef SSL_OP_NO_TLSv1_2 | |
2144 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2145 | #endif | |
e2fbf4a2 PP |
2146 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG |
2147 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2148 | #endif | |
77bb000f | 2149 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2150 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2151 | #endif |
2152 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2153 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2154 | #endif |
2155 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2156 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2157 | #endif |
2158 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2159 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2160 | #endif |
2161 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2162 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2163 | #endif |
2164 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2165 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2166 | #endif |
2167 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2168 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2169 | #endif |
2170 | }; | |
2171 | static int exim_openssl_options_size = | |
2172 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2173 | ||
c80c5570 | 2174 | |
77bb000f PP |
2175 | static BOOL |
2176 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2177 | { | |
2178 | int first = 0; | |
2179 | int last = exim_openssl_options_size; | |
2180 | while (last > first) | |
2181 | { | |
2182 | int middle = (first + last)/2; | |
2183 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2184 | if (c == 0) | |
2185 | { | |
2186 | *value = exim_openssl_options[middle].value; | |
2187 | return TRUE; | |
2188 | } | |
2189 | else if (c > 0) | |
2190 | first = middle + 1; | |
2191 | else | |
2192 | last = middle; | |
2193 | } | |
2194 | return FALSE; | |
2195 | } | |
2196 | ||
2197 | ||
2198 | ||
2199 | ||
2200 | /************************************************* | |
2201 | * OpenSSL option parsing logic * | |
2202 | *************************************************/ | |
2203 | ||
2204 | /* OpenSSL has a number of compatibility options which an administrator might | |
2205 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2206 | we look like log_selector. | |
2207 | ||
2208 | Arguments: | |
2209 | option_spec the administrator-supplied string of options | |
2210 | results ptr to long storage for the options bitmap | |
2211 | Returns success or failure | |
2212 | */ | |
2213 | ||
2214 | BOOL | |
2215 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2216 | { | |
2217 | long result, item; | |
2218 | uschar *s, *end; | |
2219 | uschar keep_c; | |
2220 | BOOL adding, item_parsed; | |
2221 | ||
0e944a0d | 2222 | result = 0L; |
b1770b6e | 2223 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 2224 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
2225 | #ifdef SSL_OP_NO_SSLv2 |
2226 | result |= SSL_OP_NO_SSLv2; | |
2227 | #endif | |
77bb000f PP |
2228 | |
2229 | if (option_spec == NULL) | |
2230 | { | |
2231 | *results = result; | |
2232 | return TRUE; | |
2233 | } | |
2234 | ||
2235 | for (s=option_spec; *s != '\0'; /**/) | |
2236 | { | |
2237 | while (isspace(*s)) ++s; | |
2238 | if (*s == '\0') | |
2239 | break; | |
2240 | if (*s != '+' && *s != '-') | |
2241 | { | |
2242 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 2243 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
2244 | return FALSE; |
2245 | } | |
2246 | adding = *s++ == '+'; | |
2247 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2248 | keep_c = *end; | |
2249 | *end = '\0'; | |
2250 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2251 | if (!item_parsed) | |
2252 | { | |
0e944a0d | 2253 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
2254 | return FALSE; |
2255 | } | |
2256 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2257 | adding ? "adding" : "removing", result, item, s); | |
2258 | if (adding) | |
2259 | result |= item; | |
2260 | else | |
2261 | result &= ~item; | |
2262 | *end = keep_c; | |
2263 | s = end; | |
2264 | } | |
2265 | ||
2266 | *results = result; | |
2267 | return TRUE; | |
2268 | } | |
2269 | ||
9d1c15ef JH |
2270 | /* vi: aw ai sw=2 |
2271 | */ | |
059ec3d9 | 2272 | /* End of tls-openssl.c */ |