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a053d125 | 1 | /* $Cambridge: exim/src/src/tls-openssl.c,v 1.28 2010/06/12 17:56:32 jetmore Exp $ */ |
059ec3d9 PH |
2 | |
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
0a49a7a4 | 7 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
059ec3d9 PH |
8 | /* See the file NOTICE for conditions of use and distribution. */ |
9 | ||
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> | |
25 | ||
26 | /* Structure for collecting random data for seeding. */ | |
27 | ||
28 | typedef struct randstuff { | |
9e3331ea TK |
29 | struct timeval tv; |
30 | pid_t p; | |
059ec3d9 PH |
31 | } randstuff; |
32 | ||
33 | /* Local static variables */ | |
34 | ||
35 | static BOOL verify_callback_called = FALSE; | |
36 | static const uschar *sid_ctx = US"exim"; | |
37 | ||
38 | static SSL_CTX *ctx = NULL; | |
39 | static SSL *ssl = NULL; | |
40 | ||
41 | static char ssl_errstring[256]; | |
42 | ||
43 | static int ssl_session_timeout = 200; | |
44 | static BOOL verify_optional = FALSE; | |
45 | ||
46 | ||
47 | ||
48 | ||
49 | ||
50 | /************************************************* | |
51 | * Handle TLS error * | |
52 | *************************************************/ | |
53 | ||
54 | /* Called from lots of places when errors occur before actually starting to do | |
55 | the TLS handshake, that is, while the session is still in clear. Always returns | |
56 | DEFER for a server and FAIL for a client so that most calls can use "return | |
57 | tls_error(...)" to do this processing and then give an appropriate return. A | |
58 | single function is used for both server and client, because it is called from | |
59 | some shared functions. | |
60 | ||
61 | Argument: | |
62 | prefix text to include in the logged error | |
63 | host NULL if setting up a server; | |
64 | the connected host if setting up a client | |
7199e1ee | 65 | msg error message or NULL if we should ask OpenSSL |
059ec3d9 PH |
66 | |
67 | Returns: OK/DEFER/FAIL | |
68 | */ | |
69 | ||
70 | static int | |
7199e1ee | 71 | tls_error(uschar *prefix, host_item *host, uschar *msg) |
059ec3d9 | 72 | { |
7199e1ee TF |
73 | if (msg == NULL) |
74 | { | |
75 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
5ca6d115 | 76 | msg = (uschar *)ssl_errstring; |
7199e1ee TF |
77 | } |
78 | ||
059ec3d9 PH |
79 | if (host == NULL) |
80 | { | |
7199e1ee | 81 | uschar *conn_info = smtp_get_connection_info(); |
5ca6d115 | 82 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
83 | conn_info += 5; |
84 | log_write(0, LOG_MAIN, "TLS error on %s (%s): %s", | |
85 | conn_info, prefix, msg); | |
059ec3d9 PH |
86 | return DEFER; |
87 | } | |
88 | else | |
89 | { | |
90 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", | |
7199e1ee | 91 | host->name, host->address, prefix, msg); |
059ec3d9 PH |
92 | return FAIL; |
93 | } | |
94 | } | |
95 | ||
96 | ||
97 | ||
98 | /************************************************* | |
99 | * Callback to generate RSA key * | |
100 | *************************************************/ | |
101 | ||
102 | /* | |
103 | Arguments: | |
104 | s SSL connection | |
105 | export not used | |
106 | keylength keylength | |
107 | ||
108 | Returns: pointer to generated key | |
109 | */ | |
110 | ||
111 | static RSA * | |
112 | rsa_callback(SSL *s, int export, int keylength) | |
113 | { | |
114 | RSA *rsa_key; | |
115 | export = export; /* Shut picky compilers up */ | |
116 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
117 | rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL); | |
118 | if (rsa_key == NULL) | |
119 | { | |
120 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
121 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
122 | ssl_errstring); | |
123 | return NULL; | |
124 | } | |
125 | return rsa_key; | |
126 | } | |
127 | ||
128 | ||
129 | ||
130 | ||
131 | /************************************************* | |
132 | * Callback for verification * | |
133 | *************************************************/ | |
134 | ||
135 | /* The SSL library does certificate verification if set up to do so. This | |
136 | callback has the current yes/no state is in "state". If verification succeeded, | |
137 | we set up the tls_peerdn string. If verification failed, what happens depends | |
138 | on whether the client is required to present a verifiable certificate or not. | |
139 | ||
140 | If verification is optional, we change the state to yes, but still log the | |
141 | verification error. For some reason (it really would help to have proper | |
142 | documentation of OpenSSL), this callback function then gets called again, this | |
143 | time with state = 1. In fact, that's useful, because we can set up the peerdn | |
144 | value, but we must take care not to set the private verified flag on the second | |
145 | time through. | |
146 | ||
147 | Note: this function is not called if the client fails to present a certificate | |
148 | when asked. We get here only if a certificate has been received. Handling of | |
149 | optional verification for this case is done when requesting SSL to verify, by | |
150 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
151 | ||
152 | Arguments: | |
153 | state current yes/no state as 1/0 | |
154 | x509ctx certificate information. | |
155 | ||
156 | Returns: 1 if verified, 0 if not | |
157 | */ | |
158 | ||
159 | static int | |
160 | verify_callback(int state, X509_STORE_CTX *x509ctx) | |
161 | { | |
162 | static uschar txt[256]; | |
163 | ||
164 | X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert), | |
165 | CS txt, sizeof(txt)); | |
166 | ||
167 | if (state == 0) | |
168 | { | |
169 | log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", | |
170 | x509ctx->error_depth, | |
171 | X509_verify_cert_error_string(x509ctx->error), | |
172 | txt); | |
173 | tls_certificate_verified = FALSE; | |
174 | verify_callback_called = TRUE; | |
175 | if (!verify_optional) return 0; /* reject */ | |
176 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " | |
177 | "tls_try_verify_hosts)\n"); | |
178 | return 1; /* accept */ | |
179 | } | |
180 | ||
181 | if (x509ctx->error_depth != 0) | |
182 | { | |
183 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n", | |
184 | x509ctx->error_depth, txt); | |
185 | } | |
186 | else | |
187 | { | |
188 | DEBUG(D_tls) debug_printf("SSL%s peer: %s\n", | |
189 | verify_callback_called? "" : " authenticated", txt); | |
190 | tls_peerdn = txt; | |
191 | } | |
192 | ||
059ec3d9 PH |
193 | if (!verify_callback_called) tls_certificate_verified = TRUE; |
194 | verify_callback_called = TRUE; | |
195 | ||
196 | return 1; /* accept */ | |
197 | } | |
198 | ||
199 | ||
200 | ||
201 | /************************************************* | |
202 | * Information callback * | |
203 | *************************************************/ | |
204 | ||
205 | /* The SSL library functions call this from time to time to indicate what they | |
206 | are doing. We copy the string to the debugging output when the level is high | |
207 | enough. | |
208 | ||
209 | Arguments: | |
210 | s the SSL connection | |
211 | where | |
212 | ret | |
213 | ||
214 | Returns: nothing | |
215 | */ | |
216 | ||
217 | static void | |
218 | info_callback(SSL *s, int where, int ret) | |
219 | { | |
220 | where = where; | |
221 | ret = ret; | |
222 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
223 | } | |
224 | ||
225 | ||
226 | ||
227 | /************************************************* | |
228 | * Initialize for DH * | |
229 | *************************************************/ | |
230 | ||
231 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
232 | ||
233 | Arguments: | |
234 | dhparam DH parameter file | |
7199e1ee | 235 | host connected host, if client; NULL if server |
059ec3d9 PH |
236 | |
237 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
238 | */ | |
239 | ||
240 | static BOOL | |
7199e1ee | 241 | init_dh(uschar *dhparam, host_item *host) |
059ec3d9 PH |
242 | { |
243 | BOOL yield = TRUE; | |
244 | BIO *bio; | |
245 | DH *dh; | |
246 | uschar *dhexpanded; | |
247 | ||
248 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded)) | |
249 | return FALSE; | |
250 | ||
251 | if (dhexpanded == NULL) return TRUE; | |
252 | ||
253 | if ((bio = BIO_new_file(CS dhexpanded, "r")) == NULL) | |
254 | { | |
7199e1ee | 255 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
5ca6d115 | 256 | host, (uschar *)strerror(errno)); |
059ec3d9 PH |
257 | yield = FALSE; |
258 | } | |
259 | else | |
260 | { | |
261 | if ((dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)) == NULL) | |
262 | { | |
7199e1ee TF |
263 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
264 | host, NULL); | |
059ec3d9 PH |
265 | yield = FALSE; |
266 | } | |
267 | else | |
268 | { | |
269 | SSL_CTX_set_tmp_dh(ctx, dh); | |
270 | DEBUG(D_tls) | |
271 | debug_printf("Diffie-Hellman initialized from %s with %d-bit key\n", | |
272 | dhexpanded, 8*DH_size(dh)); | |
273 | DH_free(dh); | |
274 | } | |
275 | BIO_free(bio); | |
276 | } | |
277 | ||
278 | return yield; | |
279 | } | |
280 | ||
281 | ||
282 | ||
283 | ||
284 | /************************************************* | |
285 | * Initialize for TLS * | |
286 | *************************************************/ | |
287 | ||
288 | /* Called from both server and client code, to do preliminary initialization of | |
289 | the library. | |
290 | ||
291 | Arguments: | |
292 | host connected host, if client; NULL if server | |
293 | dhparam DH parameter file | |
294 | certificate certificate file | |
295 | privatekey private key | |
296 | addr address if client; NULL if server (for some randomness) | |
297 | ||
298 | Returns: OK/DEFER/FAIL | |
299 | */ | |
300 | ||
301 | static int | |
c91535f3 PH |
302 | tls_init(host_item *host, uschar *dhparam, uschar *certificate, |
303 | uschar *privatekey, address_item *addr) | |
059ec3d9 | 304 | { |
77bb000f PP |
305 | long init_options; |
306 | BOOL okay; | |
307 | ||
059ec3d9 PH |
308 | SSL_load_error_strings(); /* basic set up */ |
309 | OpenSSL_add_ssl_algorithms(); | |
310 | ||
388d6564 | 311 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
77bb000f | 312 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
313 | list of available digests. */ |
314 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 315 | #endif |
a0475b69 | 316 | |
059ec3d9 PH |
317 | /* Create a context */ |
318 | ||
319 | ctx = SSL_CTX_new((host == NULL)? | |
320 | SSLv23_server_method() : SSLv23_client_method()); | |
321 | ||
7199e1ee | 322 | if (ctx == NULL) return tls_error(US"SSL_CTX_new", host, NULL); |
059ec3d9 PH |
323 | |
324 | /* It turns out that we need to seed the random number generator this early in | |
325 | order to get the full complement of ciphers to work. It took me roughly a day | |
326 | of work to discover this by experiment. | |
327 | ||
328 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
329 | there. Otherwise, we have to make something up as best we can. Double check | |
330 | afterwards. */ | |
331 | ||
332 | if (!RAND_status()) | |
333 | { | |
334 | randstuff r; | |
9e3331ea | 335 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
336 | r.p = getpid(); |
337 | ||
338 | RAND_seed((uschar *)(&r), sizeof(r)); | |
339 | RAND_seed((uschar *)big_buffer, big_buffer_size); | |
340 | if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr)); | |
341 | ||
342 | if (!RAND_status()) | |
7199e1ee | 343 | return tls_error(US"RAND_status", host, |
5ca6d115 | 344 | US"unable to seed random number generator"); |
059ec3d9 PH |
345 | } |
346 | ||
347 | /* Set up the information callback, which outputs if debugging is at a suitable | |
348 | level. */ | |
349 | ||
58c01c94 | 350 | SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); |
059ec3d9 | 351 | |
77bb000f PP |
352 | /* Apply administrator-supplied work-arounds. |
353 | Historically we applied just one requested option, | |
354 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
355 | moved to an administrator-controlled list of options to specify and | |
356 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 357 | |
77bb000f PP |
358 | No OpenSSL version number checks: the options we accept depend upon the |
359 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 360 | |
77bb000f PP |
361 | okay = tls_openssl_options_parse(openssl_options, &init_options); |
362 | if (!okay) | |
73a46702 | 363 | return tls_error(US"openssl_options parsing failed", host, NULL); |
77bb000f PP |
364 | |
365 | if (init_options) | |
366 | { | |
367 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
368 | if (!(SSL_CTX_set_options(ctx, init_options))) | |
369 | return tls_error(string_sprintf( | |
370 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL); | |
371 | } | |
372 | else | |
373 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 PH |
374 | |
375 | /* Initialize with DH parameters if supplied */ | |
376 | ||
7199e1ee | 377 | if (!init_dh(dhparam, host)) return DEFER; |
059ec3d9 PH |
378 | |
379 | /* Set up certificate and key */ | |
380 | ||
381 | if (certificate != NULL) | |
382 | { | |
383 | uschar *expanded; | |
384 | if (!expand_check(certificate, US"tls_certificate", &expanded)) | |
385 | return DEFER; | |
386 | ||
387 | if (expanded != NULL) | |
388 | { | |
389 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
390 | if (!SSL_CTX_use_certificate_chain_file(ctx, CS expanded)) | |
d6453af2 | 391 | return tls_error(string_sprintf( |
7199e1ee | 392 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), host, NULL); |
059ec3d9 PH |
393 | } |
394 | ||
395 | if (privatekey != NULL && | |
396 | !expand_check(privatekey, US"tls_privatekey", &expanded)) | |
397 | return DEFER; | |
398 | ||
c91535f3 PH |
399 | /* If expansion was forced to fail, key_expanded will be NULL. If the result |
400 | of the expansion is an empty string, ignore it also, and assume the private | |
401 | key is in the same file as the certificate. */ | |
402 | ||
403 | if (expanded != NULL && *expanded != 0) | |
059ec3d9 PH |
404 | { |
405 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
406 | if (!SSL_CTX_use_PrivateKey_file(ctx, CS expanded, SSL_FILETYPE_PEM)) | |
d6453af2 | 407 | return tls_error(string_sprintf( |
7199e1ee | 408 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), host, NULL); |
059ec3d9 PH |
409 | } |
410 | } | |
411 | ||
412 | /* Set up the RSA callback */ | |
413 | ||
414 | SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); | |
415 | ||
416 | /* Finally, set the timeout, and we are done */ | |
417 | ||
418 | SSL_CTX_set_timeout(ctx, ssl_session_timeout); | |
419 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); | |
420 | return OK; | |
421 | } | |
422 | ||
423 | ||
424 | ||
425 | ||
426 | /************************************************* | |
427 | * Get name of cipher in use * | |
428 | *************************************************/ | |
429 | ||
430 | /* The answer is left in a static buffer, and tls_cipher is set to point | |
431 | to it. | |
432 | ||
433 | Argument: pointer to an SSL structure for the connection | |
434 | Returns: nothing | |
435 | */ | |
436 | ||
437 | static void | |
438 | construct_cipher_name(SSL *ssl) | |
439 | { | |
440 | static uschar cipherbuf[256]; | |
57b3a7f5 PP |
441 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
442 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
443 | the accessor functions use const in the prototype. */ | |
444 | const SSL_CIPHER *c; | |
059ec3d9 PH |
445 | uschar *ver; |
446 | int bits; | |
447 | ||
448 | switch (ssl->session->ssl_version) | |
449 | { | |
450 | case SSL2_VERSION: | |
451 | ver = US"SSLv2"; | |
452 | break; | |
453 | ||
454 | case SSL3_VERSION: | |
455 | ver = US"SSLv3"; | |
456 | break; | |
457 | ||
458 | case TLS1_VERSION: | |
459 | ver = US"TLSv1"; | |
460 | break; | |
461 | ||
462 | default: | |
463 | ver = US"UNKNOWN"; | |
464 | } | |
465 | ||
57b3a7f5 | 466 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
059ec3d9 PH |
467 | SSL_CIPHER_get_bits(c, &bits); |
468 | ||
469 | string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver, | |
470 | SSL_CIPHER_get_name(c), bits); | |
471 | tls_cipher = cipherbuf; | |
472 | ||
473 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
474 | } | |
475 | ||
476 | ||
477 | ||
478 | ||
479 | ||
480 | /************************************************* | |
481 | * Set up for verifying certificates * | |
482 | *************************************************/ | |
483 | ||
484 | /* Called by both client and server startup | |
485 | ||
486 | Arguments: | |
487 | certs certs file or NULL | |
488 | crl CRL file or NULL | |
489 | host NULL in a server; the remote host in a client | |
490 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
491 | otherwise passed as FALSE | |
492 | ||
493 | Returns: OK/DEFER/FAIL | |
494 | */ | |
495 | ||
496 | static int | |
497 | setup_certs(uschar *certs, uschar *crl, host_item *host, BOOL optional) | |
498 | { | |
499 | uschar *expcerts, *expcrl; | |
500 | ||
501 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) | |
502 | return DEFER; | |
503 | ||
504 | if (expcerts != NULL) | |
505 | { | |
506 | struct stat statbuf; | |
507 | if (!SSL_CTX_set_default_verify_paths(ctx)) | |
7199e1ee | 508 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); |
059ec3d9 PH |
509 | |
510 | if (Ustat(expcerts, &statbuf) < 0) | |
511 | { | |
512 | log_write(0, LOG_MAIN|LOG_PANIC, | |
513 | "failed to stat %s for certificates", expcerts); | |
514 | return DEFER; | |
515 | } | |
516 | else | |
517 | { | |
518 | uschar *file, *dir; | |
519 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
520 | { file = NULL; dir = expcerts; } | |
521 | else | |
522 | { file = expcerts; dir = NULL; } | |
523 | ||
524 | /* If a certificate file is empty, the next function fails with an | |
525 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
526 | certificates are recognized, but the error message is still misleading (it | |
527 | says no certificate was supplied.) But this is better. */ | |
528 | ||
529 | if ((file == NULL || statbuf.st_size > 0) && | |
530 | !SSL_CTX_load_verify_locations(ctx, CS file, CS dir)) | |
7199e1ee | 531 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); |
059ec3d9 PH |
532 | |
533 | if (file != NULL) | |
534 | { | |
535 | SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(CS file)); | |
536 | } | |
537 | } | |
538 | ||
539 | /* Handle a certificate revocation list. */ | |
540 | ||
541 | #if OPENSSL_VERSION_NUMBER > 0x00907000L | |
542 | ||
8b417f2c PH |
543 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
544 | * merely reformatted it into the Exim code style.) | |
545 | ||
546 | * "From here I changed the code to add support for multiple crl's | |
547 | * in pem format in one file or to support hashed directory entries in | |
548 | * pem format instead of a file. This method now uses the library function | |
549 | * X509_STORE_load_locations to add the CRL location to the SSL context. | |
550 | * OpenSSL will then handle the verify against CA certs and CRLs by | |
551 | * itself in the verify callback." */ | |
552 | ||
059ec3d9 PH |
553 | if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER; |
554 | if (expcrl != NULL && *expcrl != 0) | |
555 | { | |
8b417f2c PH |
556 | struct stat statbufcrl; |
557 | if (Ustat(expcrl, &statbufcrl) < 0) | |
558 | { | |
559 | log_write(0, LOG_MAIN|LOG_PANIC, | |
560 | "failed to stat %s for certificates revocation lists", expcrl); | |
561 | return DEFER; | |
562 | } | |
563 | else | |
059ec3d9 | 564 | { |
8b417f2c PH |
565 | /* is it a file or directory? */ |
566 | uschar *file, *dir; | |
567 | X509_STORE *cvstore = SSL_CTX_get_cert_store(ctx); | |
568 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) | |
059ec3d9 | 569 | { |
8b417f2c PH |
570 | file = NULL; |
571 | dir = expcrl; | |
572 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
573 | } |
574 | else | |
575 | { | |
8b417f2c PH |
576 | file = expcrl; |
577 | dir = NULL; | |
578 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 579 | } |
8b417f2c | 580 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
7199e1ee | 581 | return tls_error(US"X509_STORE_load_locations", host, NULL); |
8b417f2c PH |
582 | |
583 | /* setting the flags to check against the complete crl chain */ | |
584 | ||
585 | X509_STORE_set_flags(cvstore, | |
586 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 587 | } |
059ec3d9 PH |
588 | } |
589 | ||
590 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ | |
591 | ||
592 | /* If verification is optional, don't fail if no certificate */ | |
593 | ||
594 | SSL_CTX_set_verify(ctx, | |
595 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), | |
596 | verify_callback); | |
597 | } | |
598 | ||
599 | return OK; | |
600 | } | |
601 | ||
602 | ||
603 | ||
604 | /************************************************* | |
605 | * Start a TLS session in a server * | |
606 | *************************************************/ | |
607 | ||
608 | /* This is called when Exim is running as a server, after having received | |
609 | the STARTTLS command. It must respond to that command, and then negotiate | |
610 | a TLS session. | |
611 | ||
612 | Arguments: | |
613 | require_ciphers allowed ciphers | |
83da1223 PH |
614 | ------------------------------------------------------ |
615 | require_mac list of allowed MACs ) Not used | |
616 | require_kx list of allowed key_exchange methods ) for | |
617 | require_proto list of allowed protocols ) OpenSSL | |
618 | ------------------------------------------------------ | |
059ec3d9 PH |
619 | |
620 | Returns: OK on success | |
621 | DEFER for errors before the start of the negotiation | |
622 | FAIL for errors during the negotation; the server can't | |
623 | continue running. | |
624 | */ | |
625 | ||
626 | int | |
83da1223 PH |
627 | tls_server_start(uschar *require_ciphers, uschar *require_mac, |
628 | uschar *require_kx, uschar *require_proto) | |
059ec3d9 PH |
629 | { |
630 | int rc; | |
631 | uschar *expciphers; | |
632 | ||
633 | /* Check for previous activation */ | |
634 | ||
635 | if (tls_active >= 0) | |
636 | { | |
5ca6d115 | 637 | tls_error(US"STARTTLS received after TLS started", NULL, US""); |
059ec3d9 PH |
638 | smtp_printf("554 Already in TLS\r\n"); |
639 | return FAIL; | |
640 | } | |
641 | ||
642 | /* Initialize the SSL library. If it fails, it will already have logged | |
643 | the error. */ | |
644 | ||
645 | rc = tls_init(NULL, tls_dhparam, tls_certificate, tls_privatekey, NULL); | |
646 | if (rc != OK) return rc; | |
647 | ||
648 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
649 | return FAIL; | |
650 | ||
651 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
652 | are separated by underscores. So that I can use either form in my tests, and | |
653 | also for general convenience, we turn underscores into hyphens here. */ | |
654 | ||
655 | if (expciphers != NULL) | |
656 | { | |
657 | uschar *s = expciphers; | |
658 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
659 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
660 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
7199e1ee | 661 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); |
059ec3d9 PH |
662 | } |
663 | ||
664 | /* If this is a host for which certificate verification is mandatory or | |
665 | optional, set up appropriately. */ | |
666 | ||
667 | tls_certificate_verified = FALSE; | |
668 | verify_callback_called = FALSE; | |
669 | ||
670 | if (verify_check_host(&tls_verify_hosts) == OK) | |
671 | { | |
672 | rc = setup_certs(tls_verify_certificates, tls_crl, NULL, FALSE); | |
673 | if (rc != OK) return rc; | |
674 | verify_optional = FALSE; | |
675 | } | |
676 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
677 | { | |
678 | rc = setup_certs(tls_verify_certificates, tls_crl, NULL, TRUE); | |
679 | if (rc != OK) return rc; | |
680 | verify_optional = TRUE; | |
681 | } | |
682 | ||
683 | /* Prepare for new connection */ | |
684 | ||
7199e1ee | 685 | if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); |
059ec3d9 PH |
686 | SSL_clear(ssl); |
687 | ||
688 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
689 | on connection, where outputting anything now upsets the clients and tends to | |
690 | make them disconnect. We need to have an explicit fflush() here, to force out | |
691 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
692 | mode, the fflush() happens when smtp_getc() is called. */ | |
693 | ||
694 | SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx)); | |
695 | if (!tls_on_connect) | |
696 | { | |
697 | smtp_printf("220 TLS go ahead\r\n"); | |
698 | fflush(smtp_out); | |
699 | } | |
700 | ||
701 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
702 | that the OpenSSL library doesn't. */ | |
703 | ||
56f5d9bd PH |
704 | SSL_set_wfd(ssl, fileno(smtp_out)); |
705 | SSL_set_rfd(ssl, fileno(smtp_in)); | |
059ec3d9 PH |
706 | SSL_set_accept_state(ssl); |
707 | ||
708 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
709 | ||
710 | sigalrm_seen = FALSE; | |
711 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
712 | rc = SSL_accept(ssl); | |
713 | alarm(0); | |
714 | ||
715 | if (rc <= 0) | |
716 | { | |
7199e1ee | 717 | tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL); |
77bb000f PP |
718 | if (ERR_get_error() == 0) |
719 | log_write(0, LOG_MAIN, | |
a053d125 | 720 | "TLS client disconnected cleanly (rejected our certificate?)"); |
059ec3d9 PH |
721 | return FAIL; |
722 | } | |
723 | ||
724 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
725 | ||
726 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
727 | and initialize things. */ | |
728 | ||
729 | construct_cipher_name(ssl); | |
730 | ||
731 | DEBUG(D_tls) | |
732 | { | |
733 | uschar buf[2048]; | |
734 | if (SSL_get_shared_ciphers(ssl, CS buf, sizeof(buf)) != NULL) | |
735 | debug_printf("Shared ciphers: %s\n", buf); | |
736 | } | |
737 | ||
738 | ||
739 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); | |
740 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
741 | ssl_xfer_eof = ssl_xfer_error = 0; | |
742 | ||
743 | receive_getc = tls_getc; | |
744 | receive_ungetc = tls_ungetc; | |
745 | receive_feof = tls_feof; | |
746 | receive_ferror = tls_ferror; | |
58eb016e | 747 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 PH |
748 | |
749 | tls_active = fileno(smtp_out); | |
750 | return OK; | |
751 | } | |
752 | ||
753 | ||
754 | ||
755 | ||
756 | ||
757 | /************************************************* | |
758 | * Start a TLS session in a client * | |
759 | *************************************************/ | |
760 | ||
761 | /* Called from the smtp transport after STARTTLS has been accepted. | |
762 | ||
763 | Argument: | |
764 | fd the fd of the connection | |
765 | host connected host (for messages) | |
83da1223 | 766 | addr the first address |
059ec3d9 PH |
767 | dhparam DH parameter file |
768 | certificate certificate file | |
769 | privatekey private key file | |
770 | verify_certs file for certificate verify | |
771 | crl file containing CRL | |
772 | require_ciphers list of allowed ciphers | |
83da1223 PH |
773 | ------------------------------------------------------ |
774 | require_mac list of allowed MACs ) Not used | |
775 | require_kx list of allowed key_exchange methods ) for | |
776 | require_proto list of allowed protocols ) OpenSSL | |
777 | ------------------------------------------------------ | |
778 | timeout startup timeout | |
059ec3d9 PH |
779 | |
780 | Returns: OK on success | |
781 | FAIL otherwise - note that tls_error() will not give DEFER | |
782 | because this is not a server | |
783 | */ | |
784 | ||
785 | int | |
786 | tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, | |
787 | uschar *certificate, uschar *privatekey, uschar *verify_certs, uschar *crl, | |
83da1223 PH |
788 | uschar *require_ciphers, uschar *require_mac, uschar *require_kx, |
789 | uschar *require_proto, int timeout) | |
059ec3d9 PH |
790 | { |
791 | static uschar txt[256]; | |
792 | uschar *expciphers; | |
793 | X509* server_cert; | |
794 | int rc; | |
795 | ||
796 | rc = tls_init(host, dhparam, certificate, privatekey, addr); | |
797 | if (rc != OK) return rc; | |
798 | ||
799 | tls_certificate_verified = FALSE; | |
800 | verify_callback_called = FALSE; | |
801 | ||
802 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
803 | return FAIL; | |
804 | ||
805 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
806 | are separated by underscores. So that I can use either form in my tests, and | |
807 | also for general convenience, we turn underscores into hyphens here. */ | |
808 | ||
809 | if (expciphers != NULL) | |
810 | { | |
811 | uschar *s = expciphers; | |
812 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
813 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
814 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
7199e1ee | 815 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); |
059ec3d9 PH |
816 | } |
817 | ||
818 | rc = setup_certs(verify_certs, crl, host, FALSE); | |
819 | if (rc != OK) return rc; | |
820 | ||
7199e1ee | 821 | if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", host, NULL); |
059ec3d9 PH |
822 | SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx)); |
823 | SSL_set_fd(ssl, fd); | |
824 | SSL_set_connect_state(ssl); | |
825 | ||
826 | /* There doesn't seem to be a built-in timeout on connection. */ | |
827 | ||
828 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
829 | sigalrm_seen = FALSE; | |
830 | alarm(timeout); | |
831 | rc = SSL_connect(ssl); | |
832 | alarm(0); | |
833 | ||
834 | if (rc <= 0) | |
7199e1ee | 835 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL); |
059ec3d9 PH |
836 | |
837 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
838 | ||
453a6645 | 839 | /* Beware anonymous ciphers which lead to server_cert being NULL */ |
059ec3d9 | 840 | server_cert = SSL_get_peer_certificate (ssl); |
453a6645 PP |
841 | if (server_cert) |
842 | { | |
843 | tls_peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert), | |
844 | CS txt, sizeof(txt)); | |
845 | tls_peerdn = txt; | |
846 | } | |
847 | else | |
848 | tls_peerdn = NULL; | |
059ec3d9 PH |
849 | |
850 | construct_cipher_name(ssl); /* Sets tls_cipher */ | |
851 | ||
852 | tls_active = fd; | |
853 | return OK; | |
854 | } | |
855 | ||
856 | ||
857 | ||
858 | ||
859 | ||
860 | /************************************************* | |
861 | * TLS version of getc * | |
862 | *************************************************/ | |
863 | ||
864 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
865 | it refills the buffer via the SSL reading function. | |
866 | ||
867 | Arguments: none | |
868 | Returns: the next character or EOF | |
869 | */ | |
870 | ||
871 | int | |
872 | tls_getc(void) | |
873 | { | |
874 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
875 | { | |
876 | int error; | |
877 | int inbytes; | |
878 | ||
879 | DEBUG(D_tls) debug_printf("Calling SSL_read(%lx, %lx, %u)\n", (long)ssl, | |
880 | (long)ssl_xfer_buffer, ssl_xfer_buffer_size); | |
881 | ||
882 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
883 | inbytes = SSL_read(ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); | |
884 | error = SSL_get_error(ssl, inbytes); | |
885 | alarm(0); | |
886 | ||
887 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
888 | closed down, not that the socket itself has been closed down. Revert to | |
889 | non-SSL handling. */ | |
890 | ||
891 | if (error == SSL_ERROR_ZERO_RETURN) | |
892 | { | |
893 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
894 | ||
895 | receive_getc = smtp_getc; | |
896 | receive_ungetc = smtp_ungetc; | |
897 | receive_feof = smtp_feof; | |
898 | receive_ferror = smtp_ferror; | |
58eb016e | 899 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 PH |
900 | |
901 | SSL_free(ssl); | |
902 | ssl = NULL; | |
903 | tls_active = -1; | |
904 | tls_cipher = NULL; | |
905 | tls_peerdn = NULL; | |
906 | ||
907 | return smtp_getc(); | |
908 | } | |
909 | ||
910 | /* Handle genuine errors */ | |
911 | ||
ba084640 PP |
912 | else if (error == SSL_ERROR_SSL) |
913 | { | |
914 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
89dd51cd | 915 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
ba084640 PP |
916 | ssl_xfer_error = 1; |
917 | return EOF; | |
918 | } | |
919 | ||
059ec3d9 PH |
920 | else if (error != SSL_ERROR_NONE) |
921 | { | |
922 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
923 | ssl_xfer_error = 1; | |
924 | return EOF; | |
925 | } | |
80a47a2c TK |
926 | #ifndef DISABLE_DKIM |
927 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
928 | #endif | |
059ec3d9 PH |
929 | ssl_xfer_buffer_hwm = inbytes; |
930 | ssl_xfer_buffer_lwm = 0; | |
931 | } | |
932 | ||
933 | /* Something in the buffer; return next uschar */ | |
934 | ||
935 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
936 | } | |
937 | ||
938 | ||
939 | ||
940 | /************************************************* | |
941 | * Read bytes from TLS channel * | |
942 | *************************************************/ | |
943 | ||
944 | /* | |
945 | Arguments: | |
946 | buff buffer of data | |
947 | len size of buffer | |
948 | ||
949 | Returns: the number of bytes read | |
950 | -1 after a failed read | |
951 | */ | |
952 | ||
953 | int | |
954 | tls_read(uschar *buff, size_t len) | |
955 | { | |
956 | int inbytes; | |
957 | int error; | |
958 | ||
959 | DEBUG(D_tls) debug_printf("Calling SSL_read(%lx, %lx, %u)\n", (long)ssl, | |
960 | (long)buff, (unsigned int)len); | |
961 | ||
962 | inbytes = SSL_read(ssl, CS buff, len); | |
963 | error = SSL_get_error(ssl, inbytes); | |
964 | ||
965 | if (error == SSL_ERROR_ZERO_RETURN) | |
966 | { | |
967 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
968 | return -1; | |
969 | } | |
970 | else if (error != SSL_ERROR_NONE) | |
971 | { | |
972 | return -1; | |
973 | } | |
974 | ||
975 | return inbytes; | |
976 | } | |
977 | ||
978 | ||
979 | ||
980 | ||
981 | ||
982 | /************************************************* | |
983 | * Write bytes down TLS channel * | |
984 | *************************************************/ | |
985 | ||
986 | /* | |
987 | Arguments: | |
988 | buff buffer of data | |
989 | len number of bytes | |
990 | ||
991 | Returns: the number of bytes after a successful write, | |
992 | -1 after a failed write | |
993 | */ | |
994 | ||
995 | int | |
996 | tls_write(const uschar *buff, size_t len) | |
997 | { | |
998 | int outbytes; | |
999 | int error; | |
1000 | int left = len; | |
1001 | ||
1002 | DEBUG(D_tls) debug_printf("tls_do_write(%lx, %d)\n", (long)buff, left); | |
1003 | while (left > 0) | |
1004 | { | |
1005 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %lx, %d)\n", (long)buff, left); | |
1006 | outbytes = SSL_write(ssl, CS buff, left); | |
1007 | error = SSL_get_error(ssl, outbytes); | |
1008 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
1009 | switch (error) | |
1010 | { | |
1011 | case SSL_ERROR_SSL: | |
1012 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1013 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
1014 | return -1; | |
1015 | ||
1016 | case SSL_ERROR_NONE: | |
1017 | left -= outbytes; | |
1018 | buff += outbytes; | |
1019 | break; | |
1020 | ||
1021 | case SSL_ERROR_ZERO_RETURN: | |
1022 | log_write(0, LOG_MAIN, "SSL channel closed on write"); | |
1023 | return -1; | |
1024 | ||
1025 | default: | |
1026 | log_write(0, LOG_MAIN, "SSL_write error %d", error); | |
1027 | return -1; | |
1028 | } | |
1029 | } | |
1030 | return len; | |
1031 | } | |
1032 | ||
1033 | ||
1034 | ||
1035 | /************************************************* | |
1036 | * Close down a TLS session * | |
1037 | *************************************************/ | |
1038 | ||
1039 | /* This is also called from within a delivery subprocess forked from the | |
1040 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1041 | would tamper with the SSL session in the parent process). | |
1042 | ||
1043 | Arguments: TRUE if SSL_shutdown is to be called | |
1044 | Returns: nothing | |
1045 | */ | |
1046 | ||
1047 | void | |
1048 | tls_close(BOOL shutdown) | |
1049 | { | |
1050 | if (tls_active < 0) return; /* TLS was not active */ | |
1051 | ||
1052 | if (shutdown) | |
1053 | { | |
1054 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); | |
1055 | SSL_shutdown(ssl); | |
1056 | } | |
1057 | ||
1058 | SSL_free(ssl); | |
1059 | ssl = NULL; | |
1060 | ||
1061 | tls_active = -1; | |
1062 | } | |
1063 | ||
36f12725 NM |
1064 | |
1065 | ||
1066 | ||
1067 | /************************************************* | |
1068 | * Report the library versions. * | |
1069 | *************************************************/ | |
1070 | ||
1071 | /* There have historically been some issues with binary compatibility in | |
1072 | OpenSSL libraries; if Exim (like many other applications) is built against | |
1073 | one version of OpenSSL but the run-time linker picks up another version, | |
1074 | it can result in serious failures, including crashing with a SIGSEGV. So | |
1075 | report the version found by the compiler and the run-time version. | |
1076 | ||
1077 | Arguments: a FILE* to print the results to | |
1078 | Returns: nothing | |
1079 | */ | |
1080 | ||
1081 | void | |
1082 | tls_version_report(FILE *f) | |
1083 | { | |
754a0503 PP |
1084 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
1085 | " Runtime: %s\n", | |
1086 | OPENSSL_VERSION_TEXT, | |
1087 | SSLeay_version(SSLEAY_VERSION)); | |
36f12725 NM |
1088 | } |
1089 | ||
9e3331ea TK |
1090 | |
1091 | ||
1092 | ||
1093 | /************************************************* | |
1094 | * Pseudo-random number generation * | |
1095 | *************************************************/ | |
1096 | ||
1097 | /* Pseudo-random number generation. The result is not expected to be | |
1098 | cryptographically strong but not so weak that someone will shoot themselves | |
1099 | in the foot using it as a nonce in input in some email header scheme or | |
1100 | whatever weirdness they'll twist this into. The result should handle fork() | |
1101 | and avoid repeating sequences. OpenSSL handles that for us. | |
1102 | ||
1103 | Arguments: | |
1104 | max range maximum | |
1105 | Returns a random number in range [0, max-1] | |
1106 | */ | |
1107 | ||
1108 | int | |
1109 | pseudo_random_number(int max) | |
1110 | { | |
1111 | unsigned int r; | |
1112 | int i, needed_len; | |
1113 | uschar *p; | |
1114 | uschar smallbuf[sizeof(r)]; | |
1115 | ||
1116 | if (max <= 1) | |
1117 | return 0; | |
1118 | ||
1119 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ | |
1120 | if (!RAND_status()) | |
1121 | { | |
1122 | randstuff r; | |
1123 | gettimeofday(&r.tv, NULL); | |
1124 | r.p = getpid(); | |
1125 | ||
1126 | RAND_seed((uschar *)(&r), sizeof(r)); | |
1127 | } | |
1128 | /* We're after pseudo-random, not random; if we still don't have enough data | |
1129 | in the internal PRNG then our options are limited. We could sleep and hope | |
1130 | for entropy to come along (prayer technique) but if the system is so depleted | |
1131 | in the first place then something is likely to just keep taking it. Instead, | |
1132 | we'll just take whatever little bit of pseudo-random we can still manage to | |
1133 | get. */ | |
1134 | ||
1135 | needed_len = sizeof(r); | |
1136 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1137 | asked for a number less than 10. */ | |
1138 | for (r = max, i = 0; r; ++i) | |
1139 | r >>= 1; | |
1140 | i = (i + 7) / 8; | |
1141 | if (i < needed_len) | |
1142 | needed_len = i; | |
1143 | ||
1144 | /* We do not care if crypto-strong */ | |
1145 | (void) RAND_pseudo_bytes(smallbuf, needed_len); | |
1146 | r = 0; | |
1147 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
1148 | { | |
1149 | r *= 256; | |
1150 | r += *p; | |
1151 | } | |
1152 | ||
1153 | /* We don't particularly care about weighted results; if someone wants | |
1154 | smooth distribution and cares enough then they should submit a patch then. */ | |
1155 | return r % max; | |
1156 | } | |
1157 | ||
77bb000f PP |
1158 | |
1159 | ||
1160 | ||
1161 | /************************************************* | |
1162 | * OpenSSL option parse * | |
1163 | *************************************************/ | |
1164 | ||
1165 | /* Parse one option for tls_openssl_options_parse below | |
1166 | ||
1167 | Arguments: | |
1168 | name one option name | |
1169 | value place to store a value for it | |
1170 | Returns success or failure in parsing | |
1171 | */ | |
1172 | ||
1173 | struct exim_openssl_option { | |
1174 | uschar *name; | |
1175 | long value; | |
1176 | }; | |
1177 | /* We could use a macro to expand, but we need the ifdef and not all the | |
1178 | options document which version they were introduced in. Policylet: include | |
1179 | all options unless explicitly for DTLS, let the administrator choose which | |
1180 | to apply. | |
1181 | ||
1182 | This list is current as of: | |
1183 | ==> 0.9.8n <== */ | |
1184 | static struct exim_openssl_option exim_openssl_options[] = { | |
1185 | /* KEEP SORTED ALPHABETICALLY! */ | |
1186 | #ifdef SSL_OP_ALL | |
73a46702 | 1187 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
1188 | #endif |
1189 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 1190 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
1191 | #endif |
1192 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 1193 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
1194 | #endif |
1195 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 1196 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
1197 | #endif |
1198 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 1199 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
1200 | #endif |
1201 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 1202 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
1203 | #endif |
1204 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 1205 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
1206 | #endif |
1207 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 1208 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
1209 | #endif |
1210 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 1211 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
1212 | #endif |
1213 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 1214 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
1215 | #endif |
1216 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 1217 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f PP |
1218 | #endif |
1219 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION | |
73a46702 | 1220 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f PP |
1221 | #endif |
1222 | #ifdef SSL_OP_SINGLE_DH_USE | |
73a46702 | 1223 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
1224 | #endif |
1225 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 1226 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
1227 | #endif |
1228 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 1229 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
1230 | #endif |
1231 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 1232 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
1233 | #endif |
1234 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 1235 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
1236 | #endif |
1237 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 1238 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
1239 | #endif |
1240 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 1241 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
1242 | #endif |
1243 | }; | |
1244 | static int exim_openssl_options_size = | |
1245 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
1246 | ||
1247 | static BOOL | |
1248 | tls_openssl_one_option_parse(uschar *name, long *value) | |
1249 | { | |
1250 | int first = 0; | |
1251 | int last = exim_openssl_options_size; | |
1252 | while (last > first) | |
1253 | { | |
1254 | int middle = (first + last)/2; | |
1255 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
1256 | if (c == 0) | |
1257 | { | |
1258 | *value = exim_openssl_options[middle].value; | |
1259 | return TRUE; | |
1260 | } | |
1261 | else if (c > 0) | |
1262 | first = middle + 1; | |
1263 | else | |
1264 | last = middle; | |
1265 | } | |
1266 | return FALSE; | |
1267 | } | |
1268 | ||
1269 | ||
1270 | ||
1271 | ||
1272 | /************************************************* | |
1273 | * OpenSSL option parsing logic * | |
1274 | *************************************************/ | |
1275 | ||
1276 | /* OpenSSL has a number of compatibility options which an administrator might | |
1277 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
1278 | we look like log_selector. | |
1279 | ||
1280 | Arguments: | |
1281 | option_spec the administrator-supplied string of options | |
1282 | results ptr to long storage for the options bitmap | |
1283 | Returns success or failure | |
1284 | */ | |
1285 | ||
1286 | BOOL | |
1287 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
1288 | { | |
1289 | long result, item; | |
1290 | uschar *s, *end; | |
1291 | uschar keep_c; | |
1292 | BOOL adding, item_parsed; | |
1293 | ||
1294 | /* We grandfather in as default the one option which we used to set always. */ | |
1295 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
1296 | result = SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; | |
1297 | #else | |
1298 | result = 0L; | |
1299 | #endif | |
1300 | ||
1301 | if (option_spec == NULL) | |
1302 | { | |
1303 | *results = result; | |
1304 | return TRUE; | |
1305 | } | |
1306 | ||
1307 | for (s=option_spec; *s != '\0'; /**/) | |
1308 | { | |
1309 | while (isspace(*s)) ++s; | |
1310 | if (*s == '\0') | |
1311 | break; | |
1312 | if (*s != '+' && *s != '-') | |
1313 | { | |
1314 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
1315 | "+ or - expected but found \"%s\"", s); | |
1316 | return FALSE; | |
1317 | } | |
1318 | adding = *s++ == '+'; | |
1319 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
1320 | keep_c = *end; | |
1321 | *end = '\0'; | |
1322 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
1323 | if (!item_parsed) | |
1324 | { | |
1325 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"", s); | |
1326 | return FALSE; | |
1327 | } | |
1328 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
1329 | adding ? "adding" : "removing", result, item, s); | |
1330 | if (adding) | |
1331 | result |= item; | |
1332 | else | |
1333 | result &= ~item; | |
1334 | *end = keep_c; | |
1335 | s = end; | |
1336 | } | |
1337 | ||
1338 | *results = result; | |
1339 | return TRUE; | |
1340 | } | |
1341 | ||
059ec3d9 | 1342 | /* End of tls-openssl.c */ |