Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
c4ceed07 | 5 | /* Copyright (c) University of Cambridge 1995 - 2012 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
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 | |
a2ff477a | 118 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, BOOL client); |
059ec3d9 | 119 | |
3f7eeb86 | 120 | /* Callbacks */ |
3bcbbbe2 | 121 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 122 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 123 | #endif |
3f7eeb86 | 124 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 125 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
126 | #endif |
127 | ||
059ec3d9 PH |
128 | |
129 | /************************************************* | |
130 | * Handle TLS error * | |
131 | *************************************************/ | |
132 | ||
133 | /* Called from lots of places when errors occur before actually starting to do | |
134 | the TLS handshake, that is, while the session is still in clear. Always returns | |
135 | DEFER for a server and FAIL for a client so that most calls can use "return | |
136 | tls_error(...)" to do this processing and then give an appropriate return. A | |
137 | single function is used for both server and client, because it is called from | |
138 | some shared functions. | |
139 | ||
140 | Argument: | |
141 | prefix text to include in the logged error | |
142 | host NULL if setting up a server; | |
143 | the connected host if setting up a client | |
7199e1ee | 144 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
145 | |
146 | Returns: OK/DEFER/FAIL | |
147 | */ | |
148 | ||
149 | static int | |
7199e1ee | 150 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 151 | { |
7199e1ee TF |
152 | if (msg == NULL) |
153 | { | |
154 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 155 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
156 | } |
157 | ||
059ec3d9 PH |
158 | if (host == NULL) |
159 | { | |
7199e1ee | 160 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 161 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
162 | conn_info += 5; |
163 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
164 | conn_info, prefix, msg); | |
059ec3d9 PH |
165 | return DEFER; |
166 | } | |
167 | else | |
168 | { | |
169 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
7199e1ee | 170 | host->name, host->address, prefix, msg); |
059ec3d9 PH |
171 | return FAIL; |
172 | } | |
173 | } | |
174 | ||
175 | ||
176 | ||
177 | /************************************************* | |
178 | * Callback to generate RSA key * | |
179 | *************************************************/ | |
180 | ||
181 | /* | |
182 | Arguments: | |
183 | s SSL connection | |
184 | export not used | |
185 | keylength keylength | |
186 | ||
187 | Returns: pointer to generated key | |
188 | */ | |
189 | ||
190 | static RSA * | |
191 | rsa_callback(SSL *s, int export, int keylength) | |
192 | { | |
193 | RSA *rsa_key; | |
194 | export = export; /* Shut picky compilers up */ | |
195 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
196 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
197 | if (rsa_key == NULL) | |
198 | { | |
199 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
200 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
201 | ssl_errstring); | |
202 | return NULL; | |
203 | } | |
204 | return rsa_key; | |
205 | } | |
206 | ||
207 | ||
208 | ||
f5d78688 JH |
209 | /* Extreme debug |
210 | #if defined(EXPERIMENTAL_OCSP) | |
211 | void | |
212 | x509_store_dump_cert_s_names(X509_STORE * store) | |
213 | { | |
214 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
215 | int i; | |
216 | static uschar name[256]; | |
217 | ||
218 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
219 | { | |
220 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
221 | if(tmp_obj->type == X509_LU_X509) | |
222 | { | |
223 | X509 * current_cert= tmp_obj->data.x509; | |
224 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
225 | debug_printf(" %s\n", name); | |
226 | } | |
227 | } | |
228 | } | |
229 | #endif | |
230 | */ | |
231 | ||
059ec3d9 PH |
232 | |
233 | /************************************************* | |
234 | * Callback for verification * | |
235 | *************************************************/ | |
236 | ||
237 | /* The SSL library does certificate verification if set up to do so. This | |
238 | callback has the current yes/no state is in "state". If verification succeeded, | |
239 | we set up the tls_peerdn string. If verification failed, what happens depends | |
240 | on whether the client is required to present a verifiable certificate or not. | |
241 | ||
242 | If verification is optional, we change the state to yes, but still log the | |
243 | verification error. For some reason (it really would help to have proper | |
244 | documentation of OpenSSL), this callback function then gets called again, this | |
245 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
246 | value, but we must take care not to set the private verified flag on the second | |
247 | time through. | |
248 | ||
249 | Note: this function is not called if the client fails to present a certificate | |
250 | when asked. We get here only if a certificate has been received. Handling of | |
251 | optional verification for this case is done when requesting SSL to verify, by | |
252 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
253 | ||
254 | Arguments: | |
255 | state current yes/no state as 1/0 | |
256 | x509ctx certificate information. | |
a2ff477a | 257 | client TRUE for client startup, FALSE for server startup |
059ec3d9 PH |
258 | |
259 | Returns: 1 if verified, 0 if not | |
260 | */ | |
261 | ||
262 | static int | |
f5d78688 | 263 | verify_callback(int state, X509_STORE_CTX *x509ctx, tls_support *tlsp, BOOL *calledp, BOOL *optionalp) |
059ec3d9 PH |
264 | { |
265 | static uschar txt[256]; | |
266 | ||
267 | X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert), | |
268 | CS txt, sizeof(txt)); | |
269 | ||
270 | if (state == 0) | |
271 | { | |
272 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
273 | x509ctx->error_depth, | |
274 | X509_verify_cert_error_string(x509ctx->error), | |
275 | txt); | |
a2ff477a JH |
276 | tlsp->certificate_verified = FALSE; |
277 | *calledp = TRUE; | |
278 | if (!*optionalp) return 0; /* reject */ | |
059ec3d9 PH |
279 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
280 | "tls_try_verify_hosts)\n"); | |
281 | return 1; /* accept */ | |
282 | } | |
283 | ||
284 | if (x509ctx->error_depth != 0) | |
285 | { | |
286 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n", | |
287 | x509ctx->error_depth, txt); | |
f5d78688 JH |
288 | #ifdef EXPERIMENTAL_OCSP |
289 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) | |
290 | { /* client, wanting stapling */ | |
291 | /* Add the server cert's signing chain as the one | |
292 | for the verification of the OCSP stapled information. */ | |
293 | ||
294 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
295 | x509ctx->current_cert)) | |
296 | ERR_clear_error(); | |
297 | } | |
298 | #endif | |
059ec3d9 PH |
299 | } |
300 | else | |
301 | { | |
302 | DEBUG(D_tls) debug_printf("SSL%s peer: %s\n", | |
a2ff477a JH |
303 | *calledp ? "" : " authenticated", txt); |
304 | tlsp->peerdn = txt; | |
059ec3d9 PH |
305 | } |
306 | ||
f5d78688 JH |
307 | /*XXX JGH: this looks bogus - we set "verified" first time through, which |
308 | will be for the root CS cert (calls work down the chain). Why should it | |
309 | not be on the last call, where we're setting peerdn? | |
310 | */ | |
a2ff477a JH |
311 | if (!*calledp) tlsp->certificate_verified = TRUE; |
312 | *calledp = TRUE; | |
059ec3d9 PH |
313 | |
314 | return 1; /* accept */ | |
315 | } | |
316 | ||
a2ff477a JH |
317 | static int |
318 | verify_callback_client(int state, X509_STORE_CTX *x509ctx) | |
319 | { | |
f5d78688 | 320 | return verify_callback(state, x509ctx, &tls_out, &client_verify_callback_called, &client_verify_optional); |
a2ff477a JH |
321 | } |
322 | ||
323 | static int | |
324 | verify_callback_server(int state, X509_STORE_CTX *x509ctx) | |
325 | { | |
f5d78688 | 326 | return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, &server_verify_optional); |
a2ff477a JH |
327 | } |
328 | ||
059ec3d9 PH |
329 | |
330 | ||
331 | /************************************************* | |
332 | * Information callback * | |
333 | *************************************************/ | |
334 | ||
335 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
336 | are doing. We copy the string to the debugging output when TLS debugging has |
337 | been requested. | |
059ec3d9 PH |
338 | |
339 | Arguments: | |
340 | s the SSL connection | |
341 | where | |
342 | ret | |
343 | ||
344 | Returns: nothing | |
345 | */ | |
346 | ||
347 | static void | |
348 | info_callback(SSL *s, int where, int ret) | |
349 | { | |
350 | where = where; | |
351 | ret = ret; | |
352 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
353 | } | |
354 | ||
355 | ||
356 | ||
357 | /************************************************* | |
358 | * Initialize for DH * | |
359 | *************************************************/ | |
360 | ||
361 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
362 | ||
363 | Arguments: | |
a799883d | 364 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 365 | host connected host, if client; NULL if server |
059ec3d9 PH |
366 | |
367 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
368 | */ | |
369 | ||
370 | static BOOL | |
a799883d | 371 | init_dh(SSL_CTX *sctx, uschar *dhparam, host_item *host) |
059ec3d9 | 372 | { |
059ec3d9 PH |
373 | BIO *bio; |
374 | DH *dh; | |
375 | uschar *dhexpanded; | |
a799883d | 376 | const char *pem; |
059ec3d9 PH |
377 | |
378 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
379 | return FALSE; | |
380 | ||
a799883d | 381 | if (dhexpanded == NULL || *dhexpanded == '\0') |
059ec3d9 | 382 | { |
a799883d | 383 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
059ec3d9 | 384 | } |
a799883d | 385 | else if (dhexpanded[0] == '/') |
059ec3d9 | 386 | { |
a799883d PP |
387 | bio = BIO_new_file(CS dhexpanded, "r"); |
388 | if (bio == NULL) | |
059ec3d9 | 389 | { |
7199e1ee | 390 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
a799883d PP |
391 | host, US strerror(errno)); |
392 | return FALSE; | |
059ec3d9 | 393 | } |
a799883d PP |
394 | } |
395 | else | |
396 | { | |
397 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 398 | { |
a799883d PP |
399 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
400 | return TRUE; | |
059ec3d9 | 401 | } |
a799883d PP |
402 | |
403 | pem = std_dh_prime_named(dhexpanded); | |
404 | if (!pem) | |
405 | { | |
406 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
407 | host, US strerror(errno)); | |
408 | return FALSE; | |
409 | } | |
410 | bio = BIO_new_mem_buf(CS pem, -1); | |
411 | } | |
412 | ||
413 | dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL); | |
414 | if (dh == NULL) | |
415 | { | |
059ec3d9 | 416 | BIO_free(bio); |
a799883d PP |
417 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
418 | host, NULL); | |
419 | return FALSE; | |
420 | } | |
421 | ||
422 | /* Even if it is larger, we silently return success rather than cause things | |
423 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
424 | * debatable choice. */ | |
425 | if ((8*DH_size(dh)) > tls_dh_max_bits) | |
426 | { | |
427 | DEBUG(D_tls) | |
428 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d", | |
429 | 8*DH_size(dh), tls_dh_max_bits); | |
430 | } | |
431 | else | |
432 | { | |
433 | SSL_CTX_set_tmp_dh(sctx, dh); | |
434 | DEBUG(D_tls) | |
435 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
436 | dhexpanded ? dhexpanded : US"default", 8*DH_size(dh)); | |
059ec3d9 PH |
437 | } |
438 | ||
a799883d PP |
439 | DH_free(dh); |
440 | BIO_free(bio); | |
441 | ||
442 | return TRUE; | |
059ec3d9 PH |
443 | } |
444 | ||
445 | ||
446 | ||
447 | ||
3f7eeb86 PP |
448 | #ifdef EXPERIMENTAL_OCSP |
449 | /************************************************* | |
450 | * Load OCSP information into state * | |
451 | *************************************************/ | |
452 | ||
f5d78688 | 453 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
454 | caller has determined this is needed. Checks validity. Debugs a message |
455 | if invalid. | |
456 | ||
457 | ASSUMES: single response, for single cert. | |
458 | ||
459 | Arguments: | |
460 | sctx the SSL_CTX* to update | |
461 | cbinfo various parts of session state | |
462 | expanded the filename putatively holding an OCSP response | |
463 | ||
464 | */ | |
465 | ||
466 | static void | |
f5d78688 | 467 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 PP |
468 | { |
469 | BIO *bio; | |
470 | OCSP_RESPONSE *resp; | |
471 | OCSP_BASICRESP *basic_response; | |
472 | OCSP_SINGLERESP *single_response; | |
473 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
474 | X509_STORE *store; | |
475 | unsigned long verify_flags; | |
476 | int status, reason, i; | |
477 | ||
f5d78688 JH |
478 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
479 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 480 | { |
f5d78688 JH |
481 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
482 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
483 | } |
484 | ||
f5d78688 | 485 | bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"); |
3f7eeb86 PP |
486 | if (!bio) |
487 | { | |
488 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 489 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
490 | return; |
491 | } | |
492 | ||
493 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
494 | BIO_free(bio); | |
495 | if (!resp) | |
496 | { | |
497 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
498 | return; | |
499 | } | |
500 | ||
501 | status = OCSP_response_status(resp); | |
502 | if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) | |
503 | { | |
504 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
505 | OCSP_response_status_str(status), status); | |
f5d78688 | 506 | goto bad; |
3f7eeb86 PP |
507 | } |
508 | ||
509 | basic_response = OCSP_response_get1_basic(resp); | |
510 | if (!basic_response) | |
511 | { | |
512 | DEBUG(D_tls) | |
513 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 514 | goto bad; |
3f7eeb86 PP |
515 | } |
516 | ||
517 | store = SSL_CTX_get_cert_store(sctx); | |
518 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ | |
519 | ||
520 | /* May need to expose ability to adjust those flags? | |
521 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
522 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
523 | ||
524 | i = OCSP_basic_verify(basic_response, NULL, store, verify_flags); | |
525 | if (i <= 0) | |
526 | { | |
527 | DEBUG(D_tls) { | |
528 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
529 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
530 | } |
531 | goto bad; | |
3f7eeb86 PP |
532 | } |
533 | ||
534 | /* Here's the simplifying assumption: there's only one response, for the | |
535 | one certificate we use, and nothing for anything else in a chain. If this | |
536 | proves false, we need to extract a cert id from our issued cert | |
537 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
538 | right cert in the stack and then calls OCSP_single_get0_status()). | |
539 | ||
540 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
541 | single_response = OCSP_resp_get0(basic_response, 0); | |
542 | if (!single_response) | |
543 | { | |
544 | DEBUG(D_tls) | |
545 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 546 | goto bad; |
3f7eeb86 PP |
547 | } |
548 | ||
549 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 550 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 551 | { |
f5d78688 JH |
552 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
553 | OCSP_cert_status_str(status), status, | |
554 | OCSP_crl_reason_str(reason), reason); | |
555 | goto bad; | |
3f7eeb86 PP |
556 | } |
557 | ||
558 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
559 | { | |
560 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 561 | goto bad; |
3f7eeb86 PP |
562 | } |
563 | ||
f5d78688 JH |
564 | supply_response: |
565 | cbinfo->u_ocsp.server.response = resp; | |
566 | return; | |
567 | ||
568 | bad: | |
569 | if (running_in_test_harness) | |
570 | { | |
571 | extern char ** environ; | |
572 | uschar ** p; | |
573 | for (p = USS environ; *p != NULL; p++) | |
574 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
575 | { | |
576 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
577 | goto supply_response; | |
578 | } | |
579 | } | |
580 | return; | |
3f7eeb86 | 581 | } |
f5d78688 | 582 | #endif /*EXPERIMENTAL_OCSP*/ |
3f7eeb86 PP |
583 | |
584 | ||
585 | ||
586 | ||
7be682ca PP |
587 | /************************************************* |
588 | * Expand key and cert file specs * | |
589 | *************************************************/ | |
590 | ||
f5d78688 | 591 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
592 | new context, if Server Name Indication was used and tls_sni was seen in |
593 | the certificate string. | |
594 | ||
595 | Arguments: | |
596 | sctx the SSL_CTX* to update | |
597 | cbinfo various parts of session state | |
598 | ||
599 | Returns: OK/DEFER/FAIL | |
600 | */ | |
601 | ||
602 | static int | |
3f7eeb86 | 603 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo) |
7be682ca PP |
604 | { |
605 | uschar *expanded; | |
606 | ||
607 | if (cbinfo->certificate == NULL) | |
608 | return OK; | |
609 | ||
d9b2312b JH |
610 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
611 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
612 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
613 | ) | |
7be682ca PP |
614 | reexpand_tls_files_for_sni = TRUE; |
615 | ||
616 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) | |
617 | return DEFER; | |
618 | ||
619 | if (expanded != NULL) | |
620 | { | |
621 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
622 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
623 | return tls_error(string_sprintf( | |
624 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
625 | cbinfo->host, NULL); | |
626 | } | |
627 | ||
628 | if (cbinfo->privatekey != NULL && | |
629 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) | |
630 | return DEFER; | |
631 | ||
632 | /* If expansion was forced to fail, key_expanded will be NULL. If the result | |
633 | of the expansion is an empty string, ignore it also, and assume the private | |
634 | key is in the same file as the certificate. */ | |
635 | ||
636 | if (expanded != NULL && *expanded != 0) | |
637 | { | |
638 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
639 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
640 | return tls_error(string_sprintf( | |
641 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); | |
642 | } | |
643 | ||
3f7eeb86 | 644 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 645 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file != NULL) |
3f7eeb86 | 646 | { |
f5d78688 | 647 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded)) |
3f7eeb86 PP |
648 | return DEFER; |
649 | ||
650 | if (expanded != NULL && *expanded != 0) | |
651 | { | |
652 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f5d78688 JH |
653 | if (cbinfo->u_ocsp.server.file_expanded && |
654 | (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 PP |
655 | { |
656 | DEBUG(D_tls) | |
657 | debug_printf("tls_ocsp_file value unchanged, using existing values.\n"); | |
658 | } else { | |
659 | ocsp_load_response(sctx, cbinfo, expanded); | |
660 | } | |
661 | } | |
662 | } | |
663 | #endif | |
664 | ||
7be682ca PP |
665 | return OK; |
666 | } | |
667 | ||
668 | ||
669 | ||
670 | ||
671 | /************************************************* | |
672 | * Callback to handle SNI * | |
673 | *************************************************/ | |
674 | ||
675 | /* Called when acting as server during the TLS session setup if a Server Name | |
676 | Indication extension was sent by the client. | |
677 | ||
678 | API documentation is OpenSSL s_server.c implementation. | |
679 | ||
680 | Arguments: | |
681 | s SSL* of the current session | |
682 | ad unknown (part of OpenSSL API) (unused) | |
683 | arg Callback of "our" registered data | |
684 | ||
685 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
686 | */ | |
687 | ||
3bcbbbe2 | 688 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
689 | static int |
690 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
691 | { | |
692 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 693 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 694 | int rc; |
3f0945ff | 695 | int old_pool = store_pool; |
7be682ca PP |
696 | |
697 | if (!servername) | |
698 | return SSL_TLSEXT_ERR_OK; | |
699 | ||
3f0945ff | 700 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
701 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
702 | ||
703 | /* Make the extension value available for expansion */ | |
3f0945ff | 704 | store_pool = POOL_PERM; |
817d9f57 | 705 | tls_in.sni = string_copy(US servername); |
3f0945ff | 706 | store_pool = old_pool; |
7be682ca PP |
707 | |
708 | if (!reexpand_tls_files_for_sni) | |
709 | return SSL_TLSEXT_ERR_OK; | |
710 | ||
711 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
712 | not confident that memcpy wouldn't break some internal reference counting. | |
713 | Especially since there's a references struct member, which would be off. */ | |
714 | ||
817d9f57 JH |
715 | server_sni = SSL_CTX_new(SSLv23_server_method()); |
716 | if (!server_sni) | |
7be682ca PP |
717 | { |
718 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
719 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
720 | return SSL_TLSEXT_ERR_NOACK; | |
721 | } | |
722 | ||
723 | /* Not sure how many of these are actually needed, since SSL object | |
724 | already exists. Might even need this selfsame callback, for reneg? */ | |
725 | ||
817d9f57 JH |
726 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
727 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
728 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
729 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
730 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
731 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
7be682ca | 732 | if (cbinfo->server_cipher_list) |
817d9f57 | 733 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
3f7eeb86 | 734 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 735 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 736 | { |
f5d78688 | 737 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 738 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
739 | } |
740 | #endif | |
7be682ca | 741 | |
a2ff477a | 742 | rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, FALSE); |
7be682ca PP |
743 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
744 | ||
3f7eeb86 PP |
745 | /* do this after setup_certs, because this can require the certs for verifying |
746 | OCSP information. */ | |
817d9f57 | 747 | rc = tls_expand_session_files(server_sni, cbinfo); |
7be682ca PP |
748 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
749 | ||
389ca47a | 750 | rc = init_dh(server_sni, cbinfo->dhparam, NULL); |
a799883d PP |
751 | if (rc != OK) return SSL_TLSEXT_ERR_NOACK; |
752 | ||
7be682ca | 753 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 754 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
755 | |
756 | return SSL_TLSEXT_ERR_OK; | |
757 | } | |
3bcbbbe2 | 758 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
759 | |
760 | ||
761 | ||
762 | ||
3f7eeb86 | 763 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 764 | |
3f7eeb86 PP |
765 | /************************************************* |
766 | * Callback to handle OCSP Stapling * | |
767 | *************************************************/ | |
768 | ||
769 | /* Called when acting as server during the TLS session setup if the client | |
770 | requests OCSP information with a Certificate Status Request. | |
771 | ||
772 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
773 | project. | |
774 | ||
775 | */ | |
776 | ||
777 | static int | |
f5d78688 | 778 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
779 | { |
780 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
781 | uschar *response_der; | |
782 | int response_der_len; | |
783 | ||
f5d78688 JH |
784 | if (log_extra_selector & LX_tls_cipher) |
785 | log_write(0, LOG_MAIN, "[%s] Recieved OCSP stapling req;%s responding", | |
786 | sender_host_address, cbinfo->u_ocsp.server.response ? "":" not"); | |
787 | else | |
788 | DEBUG(D_tls) debug_printf("Received TLS status request (OCSP stapling); %s response.", | |
789 | cbinfo->u_ocsp.server.response ? "have" : "lack"); | |
790 | ||
791 | if (!cbinfo->u_ocsp.server.response) | |
3f7eeb86 PP |
792 | return SSL_TLSEXT_ERR_NOACK; |
793 | ||
794 | response_der = NULL; | |
f5d78688 | 795 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, &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); |
3f7eeb86 PP |
800 | return SSL_TLSEXT_ERR_OK; |
801 | } | |
802 | ||
3f7eeb86 | 803 | |
f5d78688 JH |
804 | static void |
805 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
806 | { | |
807 | BIO_printf(bp, "\t%s: ", str); | |
808 | ASN1_GENERALIZEDTIME_print(bp, time); | |
809 | BIO_puts(bp, "\n"); | |
810 | } | |
811 | ||
812 | static int | |
813 | tls_client_stapling_cb(SSL *s, void *arg) | |
814 | { | |
815 | tls_ext_ctx_cb * cbinfo = arg; | |
816 | const unsigned char * p; | |
817 | int len; | |
818 | OCSP_RESPONSE * rsp; | |
819 | OCSP_BASICRESP * bs; | |
820 | int i; | |
821 | ||
822 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
823 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
824 | if(!p) | |
825 | { | |
826 | if (log_extra_selector & LX_tls_cipher) | |
827 | log_write(0, LOG_MAIN, "Received TLS status response, null content"); | |
828 | else | |
829 | DEBUG(D_tls) debug_printf(" null\n"); | |
830 | return 0; /* This is the fail case for require-ocsp; none from server */ | |
831 | } | |
832 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) | |
833 | { | |
834 | if (log_extra_selector & LX_tls_cipher) | |
835 | log_write(0, LOG_MAIN, "Received TLS status response, parse error"); | |
836 | else | |
837 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
838 | return 0; | |
839 | } | |
840 | ||
841 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
842 | { | |
843 | if (log_extra_selector & LX_tls_cipher) | |
844 | log_write(0, LOG_MAIN, "Received TLS status response, error parsing response"); | |
845 | else | |
846 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
847 | OCSP_RESPONSE_free(rsp); | |
848 | return 0; | |
849 | } | |
850 | ||
851 | /* We'd check the nonce here if we'd put one in the request. */ | |
852 | /* However that would defeat cacheability on the server so we don't. */ | |
853 | ||
854 | ||
855 | /* This section of code reworked from OpenSSL apps source; | |
856 | The OpenSSL Project retains copyright: | |
857 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
858 | */ | |
859 | { | |
860 | BIO * bp = NULL; | |
861 | OCSP_CERTID *id; | |
862 | int status, reason; | |
863 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
864 | ||
865 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
866 | ||
867 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
868 | ||
869 | /* Use the chain that verified the server cert to verify the stapled info */ | |
870 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
871 | ||
872 | if ((i = OCSP_basic_verify(bs, NULL, cbinfo->u_ocsp.client.verify_store, 0)) <= 0) | |
873 | { | |
874 | BIO_printf(bp, "OCSP response verify failure\n"); | |
875 | ERR_print_errors(bp); | |
876 | i = 0; | |
877 | goto out; | |
878 | } | |
879 | ||
880 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
881 | ||
882 | { | |
883 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
884 | OCSP_SINGLERESP * single; | |
885 | ||
886 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) | |
887 | { | |
888 | log_write(0, LOG_MAIN, "OCSP stapling with multiple responses not handled"); | |
889 | goto out; | |
890 | } | |
891 | single = OCSP_resp_get0(bs, 0); | |
892 | status = OCSP_single_get0_status(single, &reason, &rev, &thisupd, &nextupd); | |
893 | } | |
894 | ||
895 | i = 0; | |
896 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); | |
897 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
898 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
899 | { | |
900 | DEBUG(D_tls) ERR_print_errors(bp); | |
901 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
902 | goto out; | |
903 | } | |
904 | ||
905 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", OCSP_cert_status_str(status)); | |
906 | switch(status) | |
907 | { | |
908 | case V_OCSP_CERTSTATUS_GOOD: | |
909 | i = 1; | |
910 | break; | |
911 | case V_OCSP_CERTSTATUS_REVOKED: | |
912 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", | |
913 | reason != -1 ? "; reason: " : "", reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
914 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
915 | i = 0; | |
916 | break; | |
917 | default: | |
918 | log_write(0, LOG_MAIN, "Server certificate status unknown, in OCSP stapling"); | |
919 | i = 0; | |
920 | break; | |
921 | } | |
922 | out: | |
923 | BIO_free(bp); | |
924 | } | |
925 | ||
926 | OCSP_RESPONSE_free(rsp); | |
927 | return i; | |
928 | } | |
929 | #endif /*EXPERIMENTAL_OCSP*/ | |
3f7eeb86 PP |
930 | |
931 | ||
932 | ||
059ec3d9 PH |
933 | /************************************************* |
934 | * Initialize for TLS * | |
935 | *************************************************/ | |
936 | ||
937 | /* Called from both server and client code, to do preliminary initialization of | |
938 | the library. | |
939 | ||
940 | Arguments: | |
941 | host connected host, if client; NULL if server | |
942 | dhparam DH parameter file | |
943 | certificate certificate file | |
944 | privatekey private key | |
f5d78688 | 945 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 PH |
946 | addr address if client; NULL if server (for some randomness) |
947 | ||
948 | Returns: OK/DEFER/FAIL | |
949 | */ | |
950 | ||
951 | static int | |
817d9f57 | 952 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 PP |
953 | uschar *privatekey, |
954 | #ifdef EXPERIMENTAL_OCSP | |
955 | uschar *ocsp_file, | |
956 | #endif | |
817d9f57 | 957 | address_item *addr, tls_ext_ctx_cb ** cbp) |
059ec3d9 | 958 | { |
77bb000f | 959 | long init_options; |
7be682ca | 960 | int rc; |
77bb000f | 961 | BOOL okay; |
7be682ca PP |
962 | tls_ext_ctx_cb *cbinfo; |
963 | ||
964 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
965 | cbinfo->certificate = certificate; | |
966 | cbinfo->privatekey = privatekey; | |
3f7eeb86 | 967 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 JH |
968 | if ((cbinfo->is_server = host==NULL)) |
969 | { | |
970 | cbinfo->u_ocsp.server.file = ocsp_file; | |
971 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
972 | cbinfo->u_ocsp.server.response = NULL; | |
973 | } | |
974 | else | |
975 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 976 | #endif |
7be682ca PP |
977 | cbinfo->dhparam = dhparam; |
978 | cbinfo->host = host; | |
77bb000f | 979 | |
059ec3d9 PH |
980 | SSL_load_error_strings(); /* basic set up */ |
981 | OpenSSL_add_ssl_algorithms(); | |
982 | ||
388d6564 | 983 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 984 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
985 | list of available digests. */ |
986 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 987 | #endif |
a0475b69 | 988 | |
f0f5a555 PP |
989 | /* Create a context. |
990 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
991 | negotiation in the different methods; as far as I can tell, the only | |
992 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
993 | when OpenSSL is built without SSLv2 support. | |
994 | By disabling with openssl_options, we can let admins re-enable with the | |
995 | existing knob. */ | |
059ec3d9 | 996 | |
817d9f57 | 997 | *ctxp = SSL_CTX_new((host == NULL)? |
059ec3d9 PH |
998 | SSLv23_server_method() : SSLv23_client_method()); |
999 | ||
817d9f57 | 1000 | if (*ctxp == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
1001 | |
1002 | /* It turns out that we need to seed the random number generator this early in | |
1003 | order to get the full complement of ciphers to work. It took me roughly a day | |
1004 | of work to discover this by experiment. | |
1005 | ||
1006 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1007 | there. Otherwise, we have to make something up as best we can. Double check | |
1008 | afterwards. */ | |
1009 | ||
1010 | if (!RAND_status()) | |
1011 | { | |
1012 | randstuff r; | |
9e3331ea | 1013 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1014 | r.p = getpid(); |
1015 | ||
1016 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1017 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
1018 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
1019 | ||
1020 | if (!RAND_status()) | |
7199e1ee | 1021 | return tls_error(US"RAND_status", host, |
5ca6d115 | 1022 | US"unable to seed random number generator"); |
059ec3d9 PH |
1023 | } |
1024 | ||
1025 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1026 | level. */ | |
1027 | ||
817d9f57 | 1028 | SSL_CTX_set_info_callback(*ctxp, (void (*)())info_callback); |
059ec3d9 | 1029 | |
c80c5570 | 1030 | /* Automatically re-try reads/writes after renegotiation. */ |
817d9f57 | 1031 | (void) SSL_CTX_set_mode(*ctxp, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1032 | |
77bb000f PP |
1033 | /* Apply administrator-supplied work-arounds. |
1034 | Historically we applied just one requested option, | |
1035 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1036 | moved to an administrator-controlled list of options to specify and | |
1037 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1038 | |
77bb000f PP |
1039 | No OpenSSL version number checks: the options we accept depend upon the |
1040 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1041 | |
77bb000f PP |
1042 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
1043 | if (!okay) | |
73a46702 | 1044 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
1045 | |
1046 | if (init_options) | |
1047 | { | |
1048 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
817d9f57 | 1049 | if (!(SSL_CTX_set_options(*ctxp, init_options))) |
77bb000f PP |
1050 | return tls_error(string_sprintf( |
1051 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
1052 | } | |
1053 | else | |
1054 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
1055 | |
1056 | /* Initialize with DH parameters if supplied */ | |
1057 | ||
817d9f57 | 1058 | if (!init_dh(*ctxp, dhparam, host)) return DEFER; |
059ec3d9 | 1059 | |
3f7eeb86 | 1060 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1061 | |
817d9f57 | 1062 | rc = tls_expand_session_files(*ctxp, cbinfo); |
7be682ca | 1063 | if (rc != OK) return rc; |
c91535f3 | 1064 | |
7be682ca | 1065 | /* If we need to handle SNI, do so */ |
3bcbbbe2 | 1066 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
f5d78688 | 1067 | if (host == NULL) /* server */ |
3f0945ff | 1068 | { |
f5d78688 JH |
1069 | # ifdef EXPERIMENTAL_OCSP |
1070 | /* We check u_ocsp.server.file, not server.response, because we care about if | |
3f7eeb86 PP |
1071 | the option exists, not what the current expansion might be, as SNI might |
1072 | change the certificate and OCSP file in use between now and the time the | |
1073 | callback is invoked. */ | |
f5d78688 | 1074 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1075 | { |
f5d78688 | 1076 | SSL_CTX_set_tlsext_status_cb(server_ctx, tls_server_stapling_cb); |
5e55c7a9 | 1077 | SSL_CTX_set_tlsext_status_arg(server_ctx, cbinfo); |
3f7eeb86 | 1078 | } |
f5d78688 | 1079 | # endif |
3f0945ff PP |
1080 | /* We always do this, so that $tls_sni is available even if not used in |
1081 | tls_certificate */ | |
817d9f57 JH |
1082 | SSL_CTX_set_tlsext_servername_callback(*ctxp, tls_servername_cb); |
1083 | SSL_CTX_set_tlsext_servername_arg(*ctxp, cbinfo); | |
3f0945ff | 1084 | } |
f5d78688 JH |
1085 | # ifdef EXPERIMENTAL_OCSP |
1086 | else /* client */ | |
1087 | if(ocsp_file) /* wanting stapling */ | |
1088 | { | |
1089 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1090 | { | |
1091 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1092 | return FAIL; | |
1093 | } | |
1094 | SSL_CTX_set_tlsext_status_cb(*ctxp, tls_client_stapling_cb); | |
1095 | SSL_CTX_set_tlsext_status_arg(*ctxp, cbinfo); | |
1096 | } | |
1097 | # endif | |
7be682ca | 1098 | #endif |
059ec3d9 PH |
1099 | |
1100 | /* Set up the RSA callback */ | |
1101 | ||
817d9f57 | 1102 | SSL_CTX_set_tmp_rsa_callback(*ctxp, rsa_callback); |
059ec3d9 PH |
1103 | |
1104 | /* Finally, set the timeout, and we are done */ | |
1105 | ||
817d9f57 | 1106 | SSL_CTX_set_timeout(*ctxp, ssl_session_timeout); |
059ec3d9 | 1107 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1108 | |
817d9f57 | 1109 | *cbp = cbinfo; |
7be682ca | 1110 | |
059ec3d9 PH |
1111 | return OK; |
1112 | } | |
1113 | ||
1114 | ||
1115 | ||
1116 | ||
1117 | /************************************************* | |
1118 | * Get name of cipher in use * | |
1119 | *************************************************/ | |
1120 | ||
817d9f57 | 1121 | /* |
059ec3d9 | 1122 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1123 | buffer to use for answer |
1124 | size of buffer | |
1125 | pointer to number of bits for cipher | |
059ec3d9 PH |
1126 | Returns: nothing |
1127 | */ | |
1128 | ||
1129 | static void | |
817d9f57 | 1130 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1131 | { |
57b3a7f5 PP |
1132 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1133 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1134 | the accessor functions use const in the prototype. */ | |
1135 | const SSL_CIPHER *c; | |
059ec3d9 | 1136 | uschar *ver; |
059ec3d9 PH |
1137 | |
1138 | switch (ssl->session->ssl_version) | |
1139 | { | |
1140 | case SSL2_VERSION: | |
1141 | ver = US"SSLv2"; | |
1142 | break; | |
1143 | ||
1144 | case SSL3_VERSION: | |
1145 | ver = US"SSLv3"; | |
1146 | break; | |
1147 | ||
1148 | case TLS1_VERSION: | |
1149 | ver = US"TLSv1"; | |
1150 | break; | |
1151 | ||
c80c5570 PP |
1152 | #ifdef TLS1_1_VERSION |
1153 | case TLS1_1_VERSION: | |
1154 | ver = US"TLSv1.1"; | |
1155 | break; | |
1156 | #endif | |
1157 | ||
1158 | #ifdef TLS1_2_VERSION | |
1159 | case TLS1_2_VERSION: | |
1160 | ver = US"TLSv1.2"; | |
1161 | break; | |
1162 | #endif | |
1163 | ||
059ec3d9 PH |
1164 | default: |
1165 | ver = US"UNKNOWN"; | |
1166 | } | |
1167 | ||
57b3a7f5 | 1168 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1169 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1170 | |
817d9f57 JH |
1171 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1172 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1173 | |
1174 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1175 | } | |
1176 | ||
1177 | ||
1178 | ||
1179 | ||
1180 | ||
1181 | /************************************************* | |
1182 | * Set up for verifying certificates * | |
1183 | *************************************************/ | |
1184 | ||
1185 | /* Called by both client and server startup | |
1186 | ||
1187 | Arguments: | |
7be682ca | 1188 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1189 | certs certs file or NULL |
1190 | crl CRL file or NULL | |
1191 | host NULL in a server; the remote host in a client | |
1192 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1193 | otherwise passed as FALSE | |
a2ff477a | 1194 | client TRUE if called for client startup, FALSE for server startup |
059ec3d9 PH |
1195 | |
1196 | Returns: OK/DEFER/FAIL | |
1197 | */ | |
1198 | ||
1199 | static int | |
a2ff477a | 1200 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, BOOL client) |
059ec3d9 PH |
1201 | { |
1202 | uschar *expcerts, *expcrl; | |
1203 | ||
1204 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
1205 | return DEFER; | |
1206 | ||
26e72755 | 1207 | if (expcerts != NULL && *expcerts != '\0') |
059ec3d9 PH |
1208 | { |
1209 | struct stat statbuf; | |
7be682ca | 1210 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
7199e1ee | 1211 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
1212 | |
1213 | if (Ustat(expcerts, &statbuf) < 0) | |
1214 | { | |
1215 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1216 | "failed to stat %s for certificates", expcerts); | |
1217 | return DEFER; | |
1218 | } | |
1219 | else | |
1220 | { | |
1221 | uschar *file, *dir; | |
1222 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1223 | { file = NULL; dir = expcerts; } | |
1224 | else | |
1225 | { file = expcerts; dir = NULL; } | |
1226 | ||
1227 | /* If a certificate file is empty, the next function fails with an | |
1228 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1229 | certificates are recognized, but the error message is still misleading (it | |
1230 | says no certificate was supplied.) But this is better. */ | |
1231 | ||
1232 | if ((file == NULL || statbuf.st_size > 0) && | |
7be682ca | 1233 | !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) |
7199e1ee | 1234 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 PH |
1235 | |
1236 | if (file != NULL) | |
1237 | { | |
7be682ca | 1238 | SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); |
059ec3d9 PH |
1239 | } |
1240 | } | |
1241 | ||
1242 | /* Handle a certificate revocation list. */ | |
1243 | ||
1244 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
1245 | ||
8b417f2c PH |
1246 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
1247 | * merely reformatted it into the Exim code style.) | |
1248 | ||
1249 | * "From here I changed the code to add support for multiple crl's | |
1250 | * in pem format in one file or to support hashed directory entries in | |
1251 | * pem format instead of a file. This method now uses the library function | |
1252 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
1253 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
1254 | * itself in the verify callback." */ | |
1255 | ||
059ec3d9 PH |
1256 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
1257 | if (expcrl != NULL && *expcrl != 0) | |
1258 | { | |
8b417f2c PH |
1259 | struct stat statbufcrl; |
1260 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1261 | { | |
1262 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1263 | "failed to stat %s for certificates revocation lists", expcrl); | |
1264 | return DEFER; | |
1265 | } | |
1266 | else | |
059ec3d9 | 1267 | { |
8b417f2c PH |
1268 | /* is it a file or directory? */ |
1269 | uschar *file, *dir; | |
7be682ca | 1270 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1271 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1272 | { |
8b417f2c PH |
1273 | file = NULL; |
1274 | dir = expcrl; | |
1275 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1276 | } |
1277 | else | |
1278 | { | |
8b417f2c PH |
1279 | file = expcrl; |
1280 | dir = NULL; | |
1281 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1282 | } |
8b417f2c | 1283 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 1284 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
1285 | |
1286 | /* setting the flags to check against the complete crl chain */ | |
1287 | ||
1288 | X509_STORE_set_flags(cvstore, | |
1289 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1290 | } |
059ec3d9 PH |
1291 | } |
1292 | ||
1293 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
1294 | ||
1295 | /* If verification is optional, don't fail if no certificate */ | |
1296 | ||
7be682ca | 1297 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1298 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
a2ff477a | 1299 | client ? verify_callback_client : verify_callback_server); |
059ec3d9 PH |
1300 | } |
1301 | ||
1302 | return OK; | |
1303 | } | |
1304 | ||
1305 | ||
1306 | ||
1307 | /************************************************* | |
1308 | * Start a TLS session in a server * | |
1309 | *************************************************/ | |
1310 | ||
1311 | /* This is called when Exim is running as a server, after having received | |
1312 | the STARTTLS command. It must respond to that command, and then negotiate | |
1313 | a TLS session. | |
1314 | ||
1315 | Arguments: | |
1316 | require_ciphers allowed ciphers | |
1317 | ||
1318 | Returns: OK on success | |
1319 | DEFER for errors before the start of the negotiation | |
1320 | FAIL for errors during the negotation; the server can't | |
1321 | continue running. | |
1322 | */ | |
1323 | ||
1324 | int | |
17c76198 | 1325 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1326 | { |
1327 | int rc; | |
1328 | uschar *expciphers; | |
7be682ca | 1329 | tls_ext_ctx_cb *cbinfo; |
817d9f57 | 1330 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1331 | |
1332 | /* Check for previous activation */ | |
1333 | ||
817d9f57 | 1334 | if (tls_in.active >= 0) |
059ec3d9 | 1335 | { |
5ca6d115 | 1336 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
1337 | smtp_printf("554 Already in TLS\r\n"); |
1338 | return FAIL; | |
1339 | } | |
1340 | ||
1341 | /* Initialize the SSL library. If it fails, it will already have logged | |
1342 | the error. */ | |
1343 | ||
817d9f57 | 1344 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
3f7eeb86 PP |
1345 | #ifdef EXPERIMENTAL_OCSP |
1346 | tls_ocsp_file, | |
1347 | #endif | |
817d9f57 | 1348 | NULL, &server_static_cbinfo); |
059ec3d9 | 1349 | if (rc != OK) return rc; |
817d9f57 | 1350 | cbinfo = server_static_cbinfo; |
059ec3d9 PH |
1351 | |
1352 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1353 | return FAIL; | |
1354 | ||
1355 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1356 | were historically separated by underscores. So that I can use either form in my |
1357 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1358 | */ | |
059ec3d9 PH |
1359 | |
1360 | if (expciphers != NULL) | |
1361 | { | |
1362 | uschar *s = expciphers; | |
1363 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1364 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1365 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
7199e1ee | 1366 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
7be682ca | 1367 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1368 | } |
1369 | ||
1370 | /* If this is a host for which certificate verification is mandatory or | |
1371 | optional, set up appropriately. */ | |
1372 | ||
817d9f57 | 1373 | tls_in.certificate_verified = FALSE; |
a2ff477a | 1374 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1375 | |
1376 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1377 | { | |
a2ff477a | 1378 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, FALSE, FALSE); |
059ec3d9 | 1379 | if (rc != OK) return rc; |
a2ff477a | 1380 | server_verify_optional = FALSE; |
059ec3d9 PH |
1381 | } |
1382 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1383 | { | |
a2ff477a | 1384 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, TRUE, FALSE); |
059ec3d9 | 1385 | if (rc != OK) return rc; |
a2ff477a | 1386 | server_verify_optional = TRUE; |
059ec3d9 PH |
1387 | } |
1388 | ||
1389 | /* Prepare for new connection */ | |
1390 | ||
817d9f57 | 1391 | if ((server_ssl = SSL_new(server_ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
da3ad30d PP |
1392 | |
1393 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1394 | * | |
1395 | * With the SSL_clear(), we get strange interoperability bugs with | |
1396 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1397 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1398 | * | |
1399 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1400 | * session shutdown. In this case, we have a brand new object and there's no | |
1401 | * obvious reason to immediately clear it. I'm guessing that this was | |
1402 | * originally added because of incomplete initialisation which the clear fixed, | |
1403 | * in some historic release. | |
1404 | */ | |
059ec3d9 PH |
1405 | |
1406 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1407 | on connection, where outputting anything now upsets the clients and tends to | |
1408 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1409 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1410 | mode, the fflush() happens when smtp_getc() is called. */ | |
1411 | ||
817d9f57 JH |
1412 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1413 | if (!tls_in.on_connect) | |
059ec3d9 PH |
1414 | { |
1415 | smtp_printf("220 TLS go ahead\r\n"); | |
1416 | fflush(smtp_out); | |
1417 | } | |
1418 | ||
1419 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1420 | that the OpenSSL library doesn't. */ | |
1421 | ||
817d9f57 JH |
1422 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1423 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1424 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1425 | |
1426 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1427 | ||
1428 | sigalrm_seen = FALSE; | |
1429 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1430 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1431 | alarm(0); |
1432 | ||
1433 | if (rc <= 0) | |
1434 | { | |
7199e1ee | 1435 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
1436 | if (ERR_get_error() == 0) |
1437 | log_write(0, LOG_MAIN, | |
a053d125 | 1438 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
1439 | return FAIL; |
1440 | } | |
1441 | ||
1442 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
1443 | ||
1444 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1445 | and initialize things. */ | |
1446 | ||
817d9f57 JH |
1447 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
1448 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
1449 | |
1450 | DEBUG(D_tls) | |
1451 | { | |
1452 | uschar buf[2048]; | |
817d9f57 | 1453 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
1454 | debug_printf("Shared ciphers: %s\n", buf); |
1455 | } | |
1456 | ||
1457 | ||
817d9f57 JH |
1458 | /* Only used by the server-side tls (tls_in), including tls_getc. |
1459 | Client-side (tls_out) reads (seem to?) go via | |
1460 | smtp_read_response()/ip_recv(). | |
1461 | Hence no need to duplicate for _in and _out. | |
1462 | */ | |
059ec3d9 PH |
1463 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
1464 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
1465 | ssl_xfer_eof = ssl_xfer_error = 0; | |
1466 | ||
1467 | receive_getc = tls_getc; | |
1468 | receive_ungetc = tls_ungetc; | |
1469 | receive_feof = tls_feof; | |
1470 | receive_ferror = tls_ferror; | |
58eb016e | 1471 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1472 | |
817d9f57 | 1473 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
1474 | return OK; |
1475 | } | |
1476 | ||
1477 | ||
1478 | ||
1479 | ||
1480 | ||
1481 | /************************************************* | |
1482 | * Start a TLS session in a client * | |
1483 | *************************************************/ | |
1484 | ||
1485 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1486 | ||
1487 | Argument: | |
1488 | fd the fd of the connection | |
1489 | host connected host (for messages) | |
83da1223 | 1490 | addr the first address |
059ec3d9 PH |
1491 | certificate certificate file |
1492 | privatekey private key file | |
3f0945ff | 1493 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1494 | verify_certs file for certificate verify |
1495 | crl file containing CRL | |
1496 | require_ciphers list of allowed ciphers | |
54c90be1 PP |
1497 | dh_min_bits minimum number of bits acceptable in server's DH prime |
1498 | (unused in OpenSSL) | |
83da1223 | 1499 | timeout startup timeout |
059ec3d9 PH |
1500 | |
1501 | Returns: OK on success | |
1502 | FAIL otherwise - note that tls_error() will not give DEFER | |
1503 | because this is not a server | |
1504 | */ | |
1505 | ||
1506 | int | |
f5d78688 | 1507 | tls_client_start(int fd, host_item *host, address_item *addr, |
3f0945ff PP |
1508 | uschar *certificate, uschar *privatekey, uschar *sni, |
1509 | uschar *verify_certs, uschar *crl, | |
f5d78688 JH |
1510 | uschar *require_ciphers, |
1511 | #ifdef EXPERIMENTAL_OCSP | |
1512 | uschar *hosts_require_ocsp, | |
1513 | #endif | |
1514 | int dh_min_bits ARG_UNUSED, int timeout) | |
059ec3d9 PH |
1515 | { |
1516 | static uschar txt[256]; | |
1517 | uschar *expciphers; | |
1518 | X509* server_cert; | |
1519 | int rc; | |
817d9f57 | 1520 | static uschar cipherbuf[256]; |
f5d78688 JH |
1521 | #ifdef EXPERIMENTAL_OCSP |
1522 | BOOL require_ocsp = verify_check_this_host(&hosts_require_ocsp, | |
1523 | NULL, host->name, host->address, NULL) == OK; | |
1524 | #endif | |
059ec3d9 | 1525 | |
f5d78688 | 1526 | rc = tls_init(&client_ctx, host, NULL, certificate, privatekey, |
3f7eeb86 | 1527 | #ifdef EXPERIMENTAL_OCSP |
f5d78688 | 1528 | require_ocsp ? US"" : NULL, |
3f7eeb86 | 1529 | #endif |
817d9f57 | 1530 | addr, &client_static_cbinfo); |
059ec3d9 PH |
1531 | if (rc != OK) return rc; |
1532 | ||
817d9f57 | 1533 | tls_out.certificate_verified = FALSE; |
a2ff477a | 1534 | client_verify_callback_called = FALSE; |
059ec3d9 PH |
1535 | |
1536 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1537 | return FAIL; | |
1538 | ||
1539 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
1540 | are separated by underscores. So that I can use either form in my tests, and | |
1541 | also for general convenience, we turn underscores into hyphens here. */ | |
1542 | ||
1543 | if (expciphers != NULL) | |
1544 | { | |
1545 | uschar *s = expciphers; | |
1546 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1547 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1548 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
7199e1ee | 1549 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
1550 | } |
1551 | ||
a2ff477a | 1552 | rc = setup_certs(client_ctx, verify_certs, crl, host, FALSE, TRUE); |
059ec3d9 PH |
1553 | if (rc != OK) return rc; |
1554 | ||
817d9f57 JH |
1555 | if ((client_ssl = SSL_new(client_ctx)) == NULL) return tls_error(US"SSL_new", host, NULL); |
1556 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); | |
1557 | SSL_set_fd(client_ssl, fd); | |
1558 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 1559 | |
3f0945ff PP |
1560 | if (sni) |
1561 | { | |
817d9f57 | 1562 | if (!expand_check(sni, US"tls_sni", &tls_out.sni)) |
3f0945ff | 1563 | return FAIL; |
ec4b68e5 | 1564 | if (tls_out.sni == NULL) |
2c9a0e86 PP |
1565 | { |
1566 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
1567 | } | |
ec4b68e5 | 1568 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 1569 | tls_out.sni = NULL; |
3f0945ff PP |
1570 | else |
1571 | { | |
35731706 | 1572 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
1573 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
1574 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 PP |
1575 | #else |
1576 | DEBUG(D_tls) | |
1577 | debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n", | |
02d9264f | 1578 | tls_out.sni); |
35731706 | 1579 | #endif |
3f0945ff PP |
1580 | } |
1581 | } | |
1582 | ||
f5d78688 JH |
1583 | #ifdef EXPERIMENTAL_OCSP |
1584 | /* Request certificate status at connection-time. If the server | |
1585 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
1586 | if (require_ocsp) | |
1587 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); | |
1588 | #endif | |
1589 | ||
059ec3d9 PH |
1590 | /* There doesn't seem to be a built-in timeout on connection. */ |
1591 | ||
1592 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
1593 | sigalrm_seen = FALSE; | |
1594 | alarm(timeout); | |
817d9f57 | 1595 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
1596 | alarm(0); |
1597 | ||
1598 | if (rc <= 0) | |
7199e1ee | 1599 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
1600 | |
1601 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
1602 | ||
453a6645 | 1603 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
817d9f57 | 1604 | server_cert = SSL_get_peer_certificate (client_ssl); |
453a6645 PP |
1605 | if (server_cert) |
1606 | { | |
817d9f57 | 1607 | tls_out.peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), |
453a6645 | 1608 | CS txt, sizeof(txt)); |
817d9f57 | 1609 | tls_out.peerdn = txt; |
453a6645 PP |
1610 | } |
1611 | else | |
817d9f57 | 1612 | tls_out.peerdn = NULL; |
059ec3d9 | 1613 | |
817d9f57 JH |
1614 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
1615 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 1616 | |
817d9f57 | 1617 | tls_out.active = fd; |
059ec3d9 PH |
1618 | return OK; |
1619 | } | |
1620 | ||
1621 | ||
1622 | ||
1623 | ||
1624 | ||
1625 | /************************************************* | |
1626 | * TLS version of getc * | |
1627 | *************************************************/ | |
1628 | ||
1629 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1630 | it refills the buffer via the SSL reading function. | |
1631 | ||
1632 | Arguments: none | |
1633 | Returns: the next character or EOF | |
817d9f57 JH |
1634 | |
1635 | Only used by the server-side TLS. | |
059ec3d9 PH |
1636 | */ |
1637 | ||
1638 | int | |
1639 | tls_getc(void) | |
1640 | { | |
1641 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1642 | { | |
1643 | int error; | |
1644 | int inbytes; | |
1645 | ||
817d9f57 | 1646 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, |
c80c5570 | 1647 | ssl_xfer_buffer, ssl_xfer_buffer_size); |
059ec3d9 PH |
1648 | |
1649 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 JH |
1650 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); |
1651 | error = SSL_get_error(server_ssl, inbytes); | |
059ec3d9 PH |
1652 | alarm(0); |
1653 | ||
1654 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
1655 | closed down, not that the socket itself has been closed down. Revert to | |
1656 | non-SSL handling. */ | |
1657 | ||
1658 | if (error == SSL_ERROR_ZERO_RETURN) | |
1659 | { | |
1660 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1661 | ||
1662 | receive_getc = smtp_getc; | |
1663 | receive_ungetc = smtp_ungetc; | |
1664 | receive_feof = smtp_feof; | |
1665 | receive_ferror = smtp_ferror; | |
58eb016e | 1666 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1667 | |
817d9f57 JH |
1668 | SSL_free(server_ssl); |
1669 | server_ssl = NULL; | |
1670 | tls_in.active = -1; | |
1671 | tls_in.bits = 0; | |
1672 | tls_in.cipher = NULL; | |
1673 | tls_in.peerdn = NULL; | |
1674 | tls_in.sni = NULL; | |
059ec3d9 PH |
1675 | |
1676 | return smtp_getc(); | |
1677 | } | |
1678 | ||
1679 | /* Handle genuine errors */ | |
1680 | ||
ba084640 PP |
1681 | else if (error == SSL_ERROR_SSL) |
1682 | { | |
1683 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 1684 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
1685 | ssl_xfer_error = 1; |
1686 | return EOF; | |
1687 | } | |
1688 | ||
059ec3d9 PH |
1689 | else if (error != SSL_ERROR_NONE) |
1690 | { | |
1691 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
1692 | ssl_xfer_error = 1; | |
1693 | return EOF; | |
1694 | } | |
c80c5570 | 1695 | |
80a47a2c TK |
1696 | #ifndef DISABLE_DKIM |
1697 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
1698 | #endif | |
059ec3d9 PH |
1699 | ssl_xfer_buffer_hwm = inbytes; |
1700 | ssl_xfer_buffer_lwm = 0; | |
1701 | } | |
1702 | ||
1703 | /* Something in the buffer; return next uschar */ | |
1704 | ||
1705 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1706 | } | |
1707 | ||
1708 | ||
1709 | ||
1710 | /************************************************* | |
1711 | * Read bytes from TLS channel * | |
1712 | *************************************************/ | |
1713 | ||
1714 | /* | |
1715 | Arguments: | |
1716 | buff buffer of data | |
1717 | len size of buffer | |
1718 | ||
1719 | Returns: the number of bytes read | |
1720 | -1 after a failed read | |
817d9f57 JH |
1721 | |
1722 | Only used by the client-side TLS. | |
059ec3d9 PH |
1723 | */ |
1724 | ||
1725 | int | |
389ca47a | 1726 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 1727 | { |
389ca47a | 1728 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
1729 | int inbytes; |
1730 | int error; | |
1731 | ||
389ca47a | 1732 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 1733 | buff, (unsigned int)len); |
059ec3d9 | 1734 | |
389ca47a JH |
1735 | inbytes = SSL_read(ssl, CS buff, len); |
1736 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
1737 | |
1738 | if (error == SSL_ERROR_ZERO_RETURN) | |
1739 | { | |
1740 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
1741 | return -1; | |
1742 | } | |
1743 | else if (error != SSL_ERROR_NONE) | |
1744 | { | |
1745 | return -1; | |
1746 | } | |
1747 | ||
1748 | return inbytes; | |
1749 | } | |
1750 | ||
1751 | ||
1752 | ||
1753 | ||
1754 | ||
1755 | /************************************************* | |
1756 | * Write bytes down TLS channel * | |
1757 | *************************************************/ | |
1758 | ||
1759 | /* | |
1760 | Arguments: | |
817d9f57 | 1761 | is_server channel specifier |
059ec3d9 PH |
1762 | buff buffer of data |
1763 | len number of bytes | |
1764 | ||
1765 | Returns: the number of bytes after a successful write, | |
1766 | -1 after a failed write | |
817d9f57 JH |
1767 | |
1768 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1769 | */ |
1770 | ||
1771 | int | |
817d9f57 | 1772 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 PH |
1773 | { |
1774 | int outbytes; | |
1775 | int error; | |
1776 | int left = len; | |
817d9f57 | 1777 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 | 1778 | |
c80c5570 | 1779 | DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); |
059ec3d9 PH |
1780 | while (left > 0) |
1781 | { | |
c80c5570 | 1782 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
1783 | outbytes = SSL_write(ssl, CS buff, left); |
1784 | error = SSL_get_error(ssl, outbytes); | |
1785 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1786 | switch (error) | |
1787 | { | |
1788 | case SSL_ERROR_SSL: | |
1789 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1790 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1791 | return -1; | |
1792 | ||
1793 | case SSL_ERROR_NONE: | |
1794 | left -= outbytes; | |
1795 | buff += outbytes; | |
1796 | break; | |
1797 | ||
1798 | case SSL_ERROR_ZERO_RETURN: | |
1799 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1800 | return -1; | |
1801 | ||
817d9f57 JH |
1802 | case SSL_ERROR_SYSCALL: |
1803 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", | |
1804 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
1805 | strerror(errno)); | |
1806 | ||
059ec3d9 PH |
1807 | default: |
1808 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1809 | return -1; | |
1810 | } | |
1811 | } | |
1812 | return len; | |
1813 | } | |
1814 | ||
1815 | ||
1816 | ||
1817 | /************************************************* | |
1818 | * Close down a TLS session * | |
1819 | *************************************************/ | |
1820 | ||
1821 | /* This is also called from within a delivery subprocess forked from the | |
1822 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1823 | would tamper with the SSL session in the parent process). | |
1824 | ||
1825 | Arguments: TRUE if SSL_shutdown is to be called | |
1826 | Returns: nothing | |
817d9f57 JH |
1827 | |
1828 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
1829 | */ |
1830 | ||
1831 | void | |
817d9f57 | 1832 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1833 | { |
817d9f57 | 1834 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 1835 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
1836 | |
1837 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
1838 | |
1839 | if (shutdown) | |
1840 | { | |
1841 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
817d9f57 | 1842 | SSL_shutdown(*sslp); |
059ec3d9 PH |
1843 | } |
1844 | ||
817d9f57 JH |
1845 | SSL_free(*sslp); |
1846 | *sslp = NULL; | |
059ec3d9 | 1847 | |
817d9f57 | 1848 | *fdp = -1; |
059ec3d9 PH |
1849 | } |
1850 | ||
36f12725 NM |
1851 | |
1852 | ||
1853 | ||
3375e053 PP |
1854 | /************************************************* |
1855 | * Let tls_require_ciphers be checked at startup * | |
1856 | *************************************************/ | |
1857 | ||
1858 | /* The tls_require_ciphers option, if set, must be something which the | |
1859 | library can parse. | |
1860 | ||
1861 | Returns: NULL on success, or error message | |
1862 | */ | |
1863 | ||
1864 | uschar * | |
1865 | tls_validate_require_cipher(void) | |
1866 | { | |
1867 | SSL_CTX *ctx; | |
1868 | uschar *s, *expciphers, *err; | |
1869 | ||
1870 | /* this duplicates from tls_init(), we need a better "init just global | |
1871 | state, for no specific purpose" singleton function of our own */ | |
1872 | ||
1873 | SSL_load_error_strings(); | |
1874 | OpenSSL_add_ssl_algorithms(); | |
1875 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
1876 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
1877 | list of available digests. */ | |
1878 | EVP_add_digest(EVP_sha256()); | |
1879 | #endif | |
1880 | ||
1881 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1882 | return NULL; | |
1883 | ||
1884 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1885 | return US"failed to expand tls_require_ciphers"; | |
1886 | ||
1887 | if (!(expciphers && *expciphers)) | |
1888 | return NULL; | |
1889 | ||
1890 | /* normalisation ripped from above */ | |
1891 | s = expciphers; | |
1892 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
1893 | ||
1894 | err = NULL; | |
1895 | ||
1896 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
1897 | if (!ctx) | |
1898 | { | |
1899 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1900 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
1901 | } | |
1902 | ||
1903 | DEBUG(D_tls) | |
1904 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1905 | ||
1906 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
1907 | { | |
1908 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1909 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers); | |
1910 | } | |
1911 | ||
1912 | SSL_CTX_free(ctx); | |
1913 | ||
1914 | return err; | |
1915 | } | |
1916 | ||
1917 | ||
1918 | ||
1919 | ||
36f12725 NM |
1920 | /************************************************* |
1921 | * Report the library versions. * | |
1922 | *************************************************/ | |
1923 | ||
1924 | /* There have historically been some issues with binary compatibility in | |
1925 | OpenSSL libraries; if Exim (like many other applications) is built against | |
1926 | one version of OpenSSL but the run-time linker picks up another version, | |
1927 | it can result in serious failures, including crashing with a SIGSEGV. So | |
1928 | report the version found by the compiler and the run-time version. | |
1929 | ||
1930 | Arguments: a FILE* to print the results to | |
1931 | Returns: nothing | |
1932 | */ | |
1933 | ||
1934 | void | |
1935 | tls_version_report(FILE *f) | |
1936 | { | |
754a0503 PP |
1937 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
1938 | " Runtime: %s\n", | |
1939 | OPENSSL_VERSION_TEXT, | |
1940 | SSLeay_version(SSLEAY_VERSION)); | |
36f12725 NM |
1941 | } |
1942 | ||
9e3331ea TK |
1943 | |
1944 | ||
1945 | ||
1946 | /************************************************* | |
17c76198 | 1947 | * Random number generation * |
9e3331ea TK |
1948 | *************************************************/ |
1949 | ||
1950 | /* Pseudo-random number generation. The result is not expected to be | |
1951 | cryptographically strong but not so weak that someone will shoot themselves | |
1952 | in the foot using it as a nonce in input in some email header scheme or | |
1953 | whatever weirdness they'll twist this into. The result should handle fork() | |
1954 | and avoid repeating sequences. OpenSSL handles that for us. | |
1955 | ||
1956 | Arguments: | |
1957 | max range maximum | |
1958 | Returns a random number in range [0, max-1] | |
1959 | */ | |
1960 | ||
1961 | int | |
17c76198 | 1962 | vaguely_random_number(int max) |
9e3331ea TK |
1963 | { |
1964 | unsigned int r; | |
1965 | int i, needed_len; | |
1966 | uschar *p; | |
1967 | uschar smallbuf[sizeof(r)]; | |
1968 | ||
1969 | if (max <= 1) | |
1970 | return 0; | |
1971 | ||
1972 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ | |
1973 | if (!RAND_status()) | |
1974 | { | |
1975 | randstuff r; | |
1976 | gettimeofday(&r.tv, NULL); | |
1977 | r.p = getpid(); | |
1978 | ||
1979 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1980 | } | |
1981 | /* We're after pseudo-random, not random; if we still don't have enough data | |
1982 | in the internal PRNG then our options are limited. We could sleep and hope | |
1983 | for entropy to come along (prayer technique) but if the system is so depleted | |
1984 | in the first place then something is likely to just keep taking it. Instead, | |
1985 | we'll just take whatever little bit of pseudo-random we can still manage to | |
1986 | get. */ | |
1987 | ||
1988 | needed_len = sizeof(r); | |
1989 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1990 | asked for a number less than 10. */ | |
1991 | for (r = max, i = 0; r; ++i) | |
1992 | r >>= 1; | |
1993 | i = (i + 7) / 8; | |
1994 | if (i < needed_len) | |
1995 | needed_len = i; | |
1996 | ||
1997 | /* We do not care if crypto-strong */ | |
17c76198 PP |
1998 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
1999 | if (i < 0) | |
2000 | { | |
2001 | DEBUG(D_all) | |
2002 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2003 | return vaguely_random_number_fallback(max); | |
2004 | } | |
2005 | ||
9e3331ea TK |
2006 | r = 0; |
2007 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2008 | { | |
2009 | r *= 256; | |
2010 | r += *p; | |
2011 | } | |
2012 | ||
2013 | /* We don't particularly care about weighted results; if someone wants | |
2014 | smooth distribution and cares enough then they should submit a patch then. */ | |
2015 | return r % max; | |
2016 | } | |
2017 | ||
77bb000f PP |
2018 | |
2019 | ||
2020 | ||
2021 | /************************************************* | |
2022 | * OpenSSL option parse * | |
2023 | *************************************************/ | |
2024 | ||
2025 | /* Parse one option for tls_openssl_options_parse below | |
2026 | ||
2027 | Arguments: | |
2028 | name one option name | |
2029 | value place to store a value for it | |
2030 | Returns success or failure in parsing | |
2031 | */ | |
2032 | ||
2033 | struct exim_openssl_option { | |
2034 | uschar *name; | |
2035 | long value; | |
2036 | }; | |
2037 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2038 | options document which version they were introduced in. Policylet: include | |
2039 | all options unless explicitly for DTLS, let the administrator choose which | |
2040 | to apply. | |
2041 | ||
2042 | This list is current as of: | |
c80c5570 | 2043 | ==> 1.0.1b <== */ |
77bb000f PP |
2044 | static struct exim_openssl_option exim_openssl_options[] = { |
2045 | /* KEEP SORTED ALPHABETICALLY! */ | |
2046 | #ifdef SSL_OP_ALL | |
73a46702 | 2047 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2048 | #endif |
2049 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2050 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2051 | #endif |
2052 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2053 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2054 | #endif |
2055 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2056 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2057 | #endif |
2058 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2059 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2060 | #endif |
2061 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2062 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2063 | #endif |
2064 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2065 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2066 | #endif |
2067 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2068 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2069 | #endif |
2070 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2071 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2072 | #endif |
2073 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2074 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2075 | #endif |
2076 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2077 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2078 | #endif |
c80c5570 PP |
2079 | #ifdef SSL_OP_NO_COMPRESSION |
2080 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2081 | #endif | |
77bb000f | 2082 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2083 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2084 | #endif |
c0c7b2da PP |
2085 | #ifdef SSL_OP_NO_SSLv2 |
2086 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2087 | #endif | |
2088 | #ifdef SSL_OP_NO_SSLv3 | |
2089 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2090 | #endif | |
2091 | #ifdef SSL_OP_NO_TICKET | |
2092 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2093 | #endif | |
2094 | #ifdef SSL_OP_NO_TLSv1 | |
2095 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2096 | #endif | |
c80c5570 PP |
2097 | #ifdef SSL_OP_NO_TLSv1_1 |
2098 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2099 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2100 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2101 | #else | |
2102 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2103 | #endif | |
2104 | #endif | |
2105 | #ifdef SSL_OP_NO_TLSv1_2 | |
2106 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2107 | #endif | |
77bb000f | 2108 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2109 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2110 | #endif |
2111 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2112 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2113 | #endif |
2114 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2115 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2116 | #endif |
2117 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2118 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2119 | #endif |
2120 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2121 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2122 | #endif |
2123 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2124 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2125 | #endif |
2126 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2127 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2128 | #endif |
2129 | }; | |
2130 | static int exim_openssl_options_size = | |
2131 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2132 | ||
c80c5570 | 2133 | |
77bb000f PP |
2134 | static BOOL |
2135 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2136 | { | |
2137 | int first = 0; | |
2138 | int last = exim_openssl_options_size; | |
2139 | while (last > first) | |
2140 | { | |
2141 | int middle = (first + last)/2; | |
2142 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2143 | if (c == 0) | |
2144 | { | |
2145 | *value = exim_openssl_options[middle].value; | |
2146 | return TRUE; | |
2147 | } | |
2148 | else if (c > 0) | |
2149 | first = middle + 1; | |
2150 | else | |
2151 | last = middle; | |
2152 | } | |
2153 | return FALSE; | |
2154 | } | |
2155 | ||
2156 | ||
2157 | ||
2158 | ||
2159 | /************************************************* | |
2160 | * OpenSSL option parsing logic * | |
2161 | *************************************************/ | |
2162 | ||
2163 | /* OpenSSL has a number of compatibility options which an administrator might | |
2164 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
2165 | we look like log_selector. | |
2166 | ||
2167 | Arguments: | |
2168 | option_spec the administrator-supplied string of options | |
2169 | results ptr to long storage for the options bitmap | |
2170 | Returns success or failure | |
2171 | */ | |
2172 | ||
2173 | BOOL | |
2174 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
2175 | { | |
2176 | long result, item; | |
2177 | uschar *s, *end; | |
2178 | uschar keep_c; | |
2179 | BOOL adding, item_parsed; | |
2180 | ||
0e944a0d | 2181 | result = 0L; |
b1770b6e | 2182 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 2183 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
2184 | #ifdef SSL_OP_NO_SSLv2 |
2185 | result |= SSL_OP_NO_SSLv2; | |
2186 | #endif | |
77bb000f PP |
2187 | |
2188 | if (option_spec == NULL) | |
2189 | { | |
2190 | *results = result; | |
2191 | return TRUE; | |
2192 | } | |
2193 | ||
2194 | for (s=option_spec; *s != '\0'; /**/) | |
2195 | { | |
2196 | while (isspace(*s)) ++s; | |
2197 | if (*s == '\0') | |
2198 | break; | |
2199 | if (*s != '+' && *s != '-') | |
2200 | { | |
2201 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 2202 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
2203 | return FALSE; |
2204 | } | |
2205 | adding = *s++ == '+'; | |
2206 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
2207 | keep_c = *end; | |
2208 | *end = '\0'; | |
2209 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
2210 | if (!item_parsed) | |
2211 | { | |
0e944a0d | 2212 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
2213 | return FALSE; |
2214 | } | |
2215 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
2216 | adding ? "adding" : "removing", result, item, s); | |
2217 | if (adding) | |
2218 | result |= item; | |
2219 | else | |
2220 | result &= ~item; | |
2221 | *end = keep_c; | |
2222 | s = end; | |
2223 | } | |
2224 | ||
2225 | *results = result; | |
2226 | return TRUE; | |
2227 | } | |
2228 | ||
059ec3d9 | 2229 | /* End of tls-openssl.c */ |