Commit | Line | Data |
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059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
d4e5e70b | 5 | /* Copyright (c) University of Cambridge 1995 - 2017 */ |
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> | |
10ca4f1c JH |
25 | #ifndef OPENSSL_NO_ECDH |
26 | # include <openssl/ec.h> | |
27 | #endif | |
f2de3a33 | 28 | #ifndef DISABLE_OCSP |
e51c7be2 | 29 | # include <openssl/ocsp.h> |
3f7eeb86 | 30 | #endif |
85098ee7 JH |
31 | #ifdef EXPERIMENTAL_DANE |
32 | # include <danessl.h> | |
33 | #endif | |
34 | ||
3f7eeb86 | 35 | |
f2de3a33 JH |
36 | #ifndef DISABLE_OCSP |
37 | # define EXIM_OCSP_SKEW_SECONDS (300L) | |
38 | # define EXIM_OCSP_MAX_AGE (-1L) | |
3f7eeb86 | 39 | #endif |
059ec3d9 | 40 | |
3bcbbbe2 | 41 | #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) |
e51c7be2 | 42 | # define EXIM_HAVE_OPENSSL_TLSEXT |
3bcbbbe2 | 43 | #endif |
c8dfb21d JH |
44 | #if OPENSSL_VERSION_NUMBER >= 0x00908000L |
45 | # define EXIM_HAVE_RSA_GENKEY_EX | |
46 | #endif | |
47 | #if OPENSSL_VERSION_NUMBER >= 0x10100000L | |
48 | # define EXIM_HAVE_OCSP_RESP_COUNT | |
49 | #else | |
50 | # define EXIM_HAVE_EPHEM_RSA_KEX | |
51 | # define EXIM_HAVE_RAND_PSEUDO | |
52 | #endif | |
53 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
54 | # define EXIM_HAVE_SHA256 | |
55 | #endif | |
34e3241d PP |
56 | |
57 | /* | |
58 | * X509_check_host provides sane certificate hostname checking, but was added | |
59 | * to OpenSSL late, after other projects forked off the code-base. So in | |
60 | * addition to guarding against the base version number, beware that LibreSSL | |
61 | * does not (at this time) support this function. | |
62 | * | |
63 | * If LibreSSL gains a different API, perhaps via libtls, then we'll probably | |
64 | * opt to disentangle and ask a LibreSSL user to provide glue for a third | |
65 | * crypto provider for libtls instead of continuing to tie the OpenSSL glue | |
66 | * into even twistier knots. If LibreSSL gains the same API, we can just | |
67 | * change this guard and punt the issue for a while longer. | |
68 | */ | |
69 | #ifndef LIBRESSL_VERSION_NUMBER | |
70 | # if OPENSSL_VERSION_NUMBER >= 0x010100000L | |
71 | # define EXIM_HAVE_OPENSSL_CHECKHOST | |
8420742d | 72 | # define EXIM_HAVE_OPENSSL_DH_BITS |
34e3241d PP |
73 | # endif |
74 | # if OPENSSL_VERSION_NUMBER >= 0x010000000L \ | |
2dfb468b | 75 | && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L |
34e3241d PP |
76 | # define EXIM_HAVE_OPENSSL_CHECKHOST |
77 | # endif | |
11aa88b0 | 78 | #endif |
10ca4f1c | 79 | |
11aa88b0 RA |
80 | #if !defined(LIBRESSL_VERSION_NUMBER) \ |
81 | || LIBRESSL_VERSION_NUMBER >= 0x20010000L | |
10ca4f1c JH |
82 | # if !defined(OPENSSL_NO_ECDH) |
83 | # if OPENSSL_VERSION_NUMBER >= 0x0090800fL | |
84 | # define EXIM_HAVE_ECDH | |
85 | # endif | |
86 | # if OPENSSL_VERSION_NUMBER >= 0x10002000L | |
10ca4f1c JH |
87 | # define EXIM_HAVE_OPENSSL_EC_NIST2NID |
88 | # endif | |
89 | # endif | |
2dfb468b | 90 | #endif |
3bcbbbe2 | 91 | |
67791ce4 JH |
92 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
93 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
94 | # define DISABLE_OCSP | |
95 | #endif | |
96 | ||
059ec3d9 PH |
97 | /* Structure for collecting random data for seeding. */ |
98 | ||
99 | typedef struct randstuff { | |
9e3331ea TK |
100 | struct timeval tv; |
101 | pid_t p; | |
059ec3d9 PH |
102 | } randstuff; |
103 | ||
104 | /* Local static variables */ | |
105 | ||
a2ff477a JH |
106 | static BOOL client_verify_callback_called = FALSE; |
107 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
108 | static const uschar *sid_ctx = US"exim"; |
109 | ||
d4f09789 PP |
110 | /* We have three different contexts to care about. |
111 | ||
112 | Simple case: client, `client_ctx` | |
113 | As a client, we can be doing a callout or cut-through delivery while receiving | |
114 | a message. So we have a client context, which should have options initialised | |
115 | from the SMTP Transport. | |
116 | ||
117 | Server: | |
118 | There are two cases: with and without ServerNameIndication from the client. | |
119 | Given TLS SNI, we can be using different keys, certs and various other | |
120 | configuration settings, because they're re-expanded with $tls_sni set. This | |
121 | allows vhosting with TLS. This SNI is sent in the handshake. | |
122 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
123 | So as a server, we start out using `server_ctx`. | |
124 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
125 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
126 | configuration. | |
127 | */ | |
128 | ||
817d9f57 JH |
129 | static SSL_CTX *client_ctx = NULL; |
130 | static SSL_CTX *server_ctx = NULL; | |
131 | static SSL *client_ssl = NULL; | |
132 | static SSL *server_ssl = NULL; | |
389ca47a | 133 | |
35731706 | 134 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 135 | static SSL_CTX *server_sni = NULL; |
35731706 | 136 | #endif |
059ec3d9 PH |
137 | |
138 | static char ssl_errstring[256]; | |
139 | ||
140 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
141 | static BOOL client_verify_optional = FALSE; |
142 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 143 | |
f5d78688 | 144 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
145 | |
146 | ||
7be682ca PP |
147 | typedef struct tls_ext_ctx_cb { |
148 | uschar *certificate; | |
149 | uschar *privatekey; | |
f2de3a33 | 150 | #ifndef DISABLE_OCSP |
f5d78688 | 151 | BOOL is_server; |
c3033f13 | 152 | STACK_OF(X509) *verify_stack; /* chain for verifying the proof */ |
f5d78688 JH |
153 | union { |
154 | struct { | |
155 | uschar *file; | |
156 | uschar *file_expanded; | |
157 | OCSP_RESPONSE *response; | |
158 | } server; | |
159 | struct { | |
44662487 JH |
160 | X509_STORE *verify_store; /* non-null if status requested */ |
161 | BOOL verify_required; | |
f5d78688 JH |
162 | } client; |
163 | } u_ocsp; | |
3f7eeb86 | 164 | #endif |
7be682ca PP |
165 | uschar *dhparam; |
166 | /* these are cached from first expand */ | |
167 | uschar *server_cipher_list; | |
168 | /* only passed down to tls_error: */ | |
169 | host_item *host; | |
55414b25 | 170 | const uschar * verify_cert_hostnames; |
0cbf2b82 | 171 | #ifndef DISABLE_EVENT |
a7538db1 JH |
172 | uschar * event_action; |
173 | #endif | |
7be682ca PP |
174 | } tls_ext_ctx_cb; |
175 | ||
176 | /* should figure out a cleanup of API to handle state preserved per | |
177 | implementation, for various reasons, which can be void * in the APIs. | |
178 | For now, we hack around it. */ | |
817d9f57 JH |
179 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
180 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
181 | |
182 | static int | |
983207c1 | 183 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 184 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr ); |
059ec3d9 | 185 | |
3f7eeb86 | 186 | /* Callbacks */ |
3bcbbbe2 | 187 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 188 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 189 | #endif |
f2de3a33 | 190 | #ifndef DISABLE_OCSP |
f5d78688 | 191 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
192 | #endif |
193 | ||
059ec3d9 PH |
194 | |
195 | /************************************************* | |
196 | * Handle TLS error * | |
197 | *************************************************/ | |
198 | ||
199 | /* Called from lots of places when errors occur before actually starting to do | |
200 | the TLS handshake, that is, while the session is still in clear. Always returns | |
201 | DEFER for a server and FAIL for a client so that most calls can use "return | |
202 | tls_error(...)" to do this processing and then give an appropriate return. A | |
203 | single function is used for both server and client, because it is called from | |
204 | some shared functions. | |
205 | ||
206 | Argument: | |
207 | prefix text to include in the logged error | |
208 | host NULL if setting up a server; | |
209 | the connected host if setting up a client | |
7199e1ee | 210 | msg error message or NULL if we should ask OpenSSL |
cf0c6164 | 211 | errstr pointer to output error message |
059ec3d9 PH |
212 | |
213 | Returns: OK/DEFER/FAIL | |
214 | */ | |
215 | ||
216 | static int | |
cf0c6164 | 217 | tls_error(uschar * prefix, const host_item * host, uschar * msg, uschar ** errstr) |
059ec3d9 | 218 | { |
c562fd30 | 219 | if (!msg) |
7199e1ee TF |
220 | { |
221 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
cf0c6164 | 222 | msg = US ssl_errstring; |
7199e1ee TF |
223 | } |
224 | ||
cf0c6164 JH |
225 | if (errstr) *errstr = string_sprintf("(%s): %s", prefix, msg); |
226 | return host ? FAIL : DEFER; | |
059ec3d9 PH |
227 | } |
228 | ||
229 | ||
230 | ||
c8dfb21d | 231 | #ifdef EXIM_HAVE_EPHEM_RSA_KEX |
059ec3d9 PH |
232 | /************************************************* |
233 | * Callback to generate RSA key * | |
234 | *************************************************/ | |
235 | ||
236 | /* | |
237 | Arguments: | |
238 | s SSL connection | |
239 | export not used | |
240 | keylength keylength | |
241 | ||
242 | Returns: pointer to generated key | |
243 | */ | |
244 | ||
245 | static RSA * | |
246 | rsa_callback(SSL *s, int export, int keylength) | |
247 | { | |
248 | RSA *rsa_key; | |
c8dfb21d JH |
249 | #ifdef EXIM_HAVE_RSA_GENKEY_EX |
250 | BIGNUM *bn = BN_new(); | |
251 | #endif | |
252 | ||
059ec3d9 PH |
253 | export = export; /* Shut picky compilers up */ |
254 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
c8dfb21d JH |
255 | |
256 | #ifdef EXIM_HAVE_RSA_GENKEY_EX | |
257 | if ( !BN_set_word(bn, (unsigned long)RSA_F4) | |
f2cb6292 | 258 | || !(rsa_key = RSA_new()) |
c8dfb21d JH |
259 | || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL) |
260 | ) | |
261 | #else | |
23bb6982 | 262 | if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL))) |
c8dfb21d JH |
263 | #endif |
264 | ||
059ec3d9 PH |
265 | { |
266 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
267 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", | |
268 | ssl_errstring); | |
269 | return NULL; | |
270 | } | |
271 | return rsa_key; | |
272 | } | |
c8dfb21d | 273 | #endif |
059ec3d9 PH |
274 | |
275 | ||
276 | ||
f5d78688 | 277 | /* Extreme debug |
f2de3a33 | 278 | #ifndef DISABLE_OCSP |
f5d78688 JH |
279 | void |
280 | x509_store_dump_cert_s_names(X509_STORE * store) | |
281 | { | |
282 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
283 | int i; | |
284 | static uschar name[256]; | |
285 | ||
286 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
287 | { | |
288 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
289 | if(tmp_obj->type == X509_LU_X509) | |
290 | { | |
291 | X509 * current_cert= tmp_obj->data.x509; | |
292 | X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name)); | |
f69979cf | 293 | name[sizeof(name)-1] = '\0'; |
f5d78688 JH |
294 | debug_printf(" %s\n", name); |
295 | } | |
296 | } | |
297 | } | |
298 | #endif | |
299 | */ | |
300 | ||
059ec3d9 | 301 | |
0cbf2b82 | 302 | #ifndef DISABLE_EVENT |
f69979cf JH |
303 | static int |
304 | verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn, | |
305 | BOOL *calledp, const BOOL *optionalp, const uschar * what) | |
306 | { | |
307 | uschar * ev; | |
308 | uschar * yield; | |
309 | X509 * old_cert; | |
310 | ||
311 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; | |
312 | if (ev) | |
313 | { | |
aaba7d03 | 314 | DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth); |
f69979cf JH |
315 | old_cert = tlsp->peercert; |
316 | tlsp->peercert = X509_dup(cert); | |
317 | /* NB we do not bother setting peerdn */ | |
318 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) | |
319 | { | |
320 | log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: " | |
321 | "depth=%d cert=%s: %s", | |
322 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
323 | what, depth, dn, yield); | |
324 | *calledp = TRUE; | |
325 | if (!*optionalp) | |
326 | { | |
327 | if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */ | |
328 | return 1; /* reject (leaving peercert set) */ | |
329 | } | |
330 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
331 | "(host in tls_try_verify_hosts)\n"); | |
332 | } | |
333 | X509_free(tlsp->peercert); | |
334 | tlsp->peercert = old_cert; | |
335 | } | |
336 | return 0; | |
337 | } | |
338 | #endif | |
339 | ||
059ec3d9 PH |
340 | /************************************************* |
341 | * Callback for verification * | |
342 | *************************************************/ | |
343 | ||
344 | /* The SSL library does certificate verification if set up to do so. This | |
345 | callback has the current yes/no state is in "state". If verification succeeded, | |
f69979cf JH |
346 | we set the certificate-verified flag. If verification failed, what happens |
347 | depends on whether the client is required to present a verifiable certificate | |
348 | or not. | |
059ec3d9 PH |
349 | |
350 | If verification is optional, we change the state to yes, but still log the | |
351 | verification error. For some reason (it really would help to have proper | |
352 | documentation of OpenSSL), this callback function then gets called again, this | |
f69979cf JH |
353 | time with state = 1. We must take care not to set the private verified flag on |
354 | the second time through. | |
059ec3d9 PH |
355 | |
356 | Note: this function is not called if the client fails to present a certificate | |
357 | when asked. We get here only if a certificate has been received. Handling of | |
358 | optional verification for this case is done when requesting SSL to verify, by | |
359 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
360 | ||
a7538db1 JH |
361 | May be called multiple times for different issues with a certificate, even |
362 | for a given "depth" in the certificate chain. | |
363 | ||
059ec3d9 | 364 | Arguments: |
f2f2c91b JH |
365 | preverify_ok current yes/no state as 1/0 |
366 | x509ctx certificate information. | |
367 | tlsp per-direction (client vs. server) support data | |
368 | calledp has-been-called flag | |
369 | optionalp verification-is-optional flag | |
059ec3d9 | 370 | |
f2f2c91b | 371 | Returns: 0 if verification should fail, otherwise 1 |
059ec3d9 PH |
372 | */ |
373 | ||
374 | static int | |
f2f2c91b | 375 | verify_callback(int preverify_ok, X509_STORE_CTX *x509ctx, |
421aff85 | 376 | tls_support *tlsp, BOOL *calledp, BOOL *optionalp) |
059ec3d9 | 377 | { |
421aff85 | 378 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 379 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 380 | uschar dn[256]; |
059ec3d9 | 381 | |
f69979cf JH |
382 | X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn)); |
383 | dn[sizeof(dn)-1] = '\0'; | |
059ec3d9 | 384 | |
f2f2c91b | 385 | if (preverify_ok == 0) |
059ec3d9 | 386 | { |
f77197ae JH |
387 | uschar * extra = verify_mode ? string_sprintf(" (during %c-verify for [%s])", |
388 | *verify_mode, sender_host_address) | |
389 | : US""; | |
390 | log_write(0, LOG_MAIN, "[%s] SSL verify error%s: depth=%d error=%s cert=%s", | |
391 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
392 | extra, depth, | |
393 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), dn); | |
a2ff477a | 394 | *calledp = TRUE; |
9d1c15ef JH |
395 | if (!*optionalp) |
396 | { | |
f69979cf JH |
397 | if (!tlsp->peercert) |
398 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
399 | return 0; /* reject */ | |
9d1c15ef | 400 | } |
059ec3d9 PH |
401 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
402 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
403 | } |
404 | ||
a7538db1 | 405 | else if (depth != 0) |
059ec3d9 | 406 | { |
f69979cf | 407 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn); |
f2de3a33 | 408 | #ifndef DISABLE_OCSP |
f5d78688 JH |
409 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
410 | { /* client, wanting stapling */ | |
411 | /* Add the server cert's signing chain as the one | |
412 | for the verification of the OCSP stapled information. */ | |
94431adb | 413 | |
f5d78688 | 414 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, |
421aff85 | 415 | cert)) |
f5d78688 | 416 | ERR_clear_error(); |
c3033f13 | 417 | sk_X509_push(client_static_cbinfo->verify_stack, cert); |
f5d78688 | 418 | } |
a7538db1 | 419 | #endif |
0cbf2b82 | 420 | #ifndef DISABLE_EVENT |
f69979cf JH |
421 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
422 | return 0; /* reject, with peercert set */ | |
f5d78688 | 423 | #endif |
059ec3d9 PH |
424 | } |
425 | else | |
426 | { | |
55414b25 | 427 | const uschar * verify_cert_hostnames; |
e51c7be2 | 428 | |
e51c7be2 JH |
429 | if ( tlsp == &tls_out |
430 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
431 | /* client, wanting hostname check */ | |
e51c7be2 | 432 | { |
f69979cf | 433 | |
740f36d4 | 434 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
f69979cf JH |
435 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
436 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
437 | # endif | |
438 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
439 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
440 | # endif | |
e51c7be2 | 441 | int sep = 0; |
55414b25 | 442 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 443 | uschar * name; |
d8e7834a JH |
444 | int rc; |
445 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
f40d5be3 | 446 | if ((rc = X509_check_host(cert, CCS name, 0, |
8d692470 | 447 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
740f36d4 JH |
448 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS, |
449 | NULL))) | |
d8e7834a JH |
450 | { |
451 | if (rc < 0) | |
452 | { | |
93a6fce2 | 453 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
f77197ae | 454 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
455 | name = NULL; |
456 | } | |
e51c7be2 | 457 | break; |
d8e7834a | 458 | } |
e51c7be2 | 459 | if (!name) |
f69979cf | 460 | #else |
e51c7be2 | 461 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) |
f69979cf | 462 | #endif |
e51c7be2 | 463 | { |
f77197ae JH |
464 | uschar * extra = verify_mode |
465 | ? string_sprintf(" (during %c-verify for [%s])", | |
466 | *verify_mode, sender_host_address) | |
467 | : US""; | |
e51c7be2 | 468 | log_write(0, LOG_MAIN, |
f77197ae JH |
469 | "[%s] SSL verify error%s: certificate name mismatch: DN=\"%s\" H=\"%s\"", |
470 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
471 | extra, dn, verify_cert_hostnames); | |
a3ef7310 JH |
472 | *calledp = TRUE; |
473 | if (!*optionalp) | |
f69979cf JH |
474 | { |
475 | if (!tlsp->peercert) | |
476 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
477 | return 0; /* reject */ | |
478 | } | |
a3ef7310 JH |
479 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
480 | "tls_try_verify_hosts)\n"); | |
e51c7be2 | 481 | } |
f69979cf | 482 | } |
e51c7be2 | 483 | |
0cbf2b82 | 484 | #ifndef DISABLE_EVENT |
f69979cf JH |
485 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
486 | return 0; /* reject, with peercert set */ | |
e51c7be2 JH |
487 | #endif |
488 | ||
93dcb1c2 | 489 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
f69979cf | 490 | *calledp ? "" : " authenticated", dn); |
93dcb1c2 JH |
491 | if (!*calledp) tlsp->certificate_verified = TRUE; |
492 | *calledp = TRUE; | |
059ec3d9 PH |
493 | } |
494 | ||
a7538db1 | 495 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
496 | } |
497 | ||
a2ff477a | 498 | static int |
f2f2c91b | 499 | verify_callback_client(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 500 | { |
f2f2c91b JH |
501 | return verify_callback(preverify_ok, x509ctx, &tls_out, |
502 | &client_verify_callback_called, &client_verify_optional); | |
a2ff477a JH |
503 | } |
504 | ||
505 | static int | |
f2f2c91b | 506 | verify_callback_server(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 507 | { |
f2f2c91b JH |
508 | return verify_callback(preverify_ok, x509ctx, &tls_in, |
509 | &server_verify_callback_called, &server_verify_optional); | |
a2ff477a JH |
510 | } |
511 | ||
059ec3d9 | 512 | |
e5cccda9 | 513 | #ifdef EXPERIMENTAL_DANE |
53a7196b | 514 | |
e5cccda9 JH |
515 | /* This gets called *by* the dane library verify callback, which interposes |
516 | itself. | |
517 | */ | |
518 | static int | |
f2f2c91b | 519 | verify_callback_client_dane(int preverify_ok, X509_STORE_CTX * x509ctx) |
e5cccda9 JH |
520 | { |
521 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
f69979cf | 522 | uschar dn[256]; |
83b27293 | 523 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
5c75db2e | 524 | #ifndef DISABLE_EVENT |
f69979cf | 525 | BOOL dummy_called, optional = FALSE; |
83b27293 | 526 | #endif |
e5cccda9 | 527 | |
f69979cf JH |
528 | X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn)); |
529 | dn[sizeof(dn)-1] = '\0'; | |
e5cccda9 | 530 | |
f2f2c91b JH |
531 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s depth %d %s\n", |
532 | preverify_ok ? "ok":"BAD", depth, dn); | |
e5cccda9 | 533 | |
0cbf2b82 | 534 | #ifndef DISABLE_EVENT |
f69979cf JH |
535 | if (verify_event(&tls_out, cert, depth, dn, |
536 | &dummy_called, &optional, US"DANE")) | |
537 | return 0; /* reject, with peercert set */ | |
83b27293 JH |
538 | #endif |
539 | ||
f2f2c91b | 540 | if (preverify_ok == 1) |
53a7196b | 541 | tls_out.dane_verified = |
e5cccda9 | 542 | tls_out.certificate_verified = TRUE; |
f2f2c91b JH |
543 | else |
544 | { | |
545 | int err = X509_STORE_CTX_get_error(x509ctx); | |
546 | DEBUG(D_tls) | |
547 | debug_printf(" - err %d '%s'\n", err, X509_verify_cert_error_string(err)); | |
3c51463e | 548 | if (err == X509_V_ERR_APPLICATION_VERIFICATION) |
f2f2c91b JH |
549 | preverify_ok = 1; |
550 | } | |
551 | return preverify_ok; | |
e5cccda9 | 552 | } |
53a7196b JH |
553 | |
554 | #endif /*EXPERIMENTAL_DANE*/ | |
e5cccda9 | 555 | |
059ec3d9 PH |
556 | |
557 | /************************************************* | |
558 | * Information callback * | |
559 | *************************************************/ | |
560 | ||
561 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
562 | are doing. We copy the string to the debugging output when TLS debugging has |
563 | been requested. | |
059ec3d9 PH |
564 | |
565 | Arguments: | |
566 | s the SSL connection | |
567 | where | |
568 | ret | |
569 | ||
570 | Returns: nothing | |
571 | */ | |
572 | ||
573 | static void | |
574 | info_callback(SSL *s, int where, int ret) | |
575 | { | |
576 | where = where; | |
577 | ret = ret; | |
578 | DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s)); | |
579 | } | |
580 | ||
581 | ||
582 | ||
583 | /************************************************* | |
584 | * Initialize for DH * | |
585 | *************************************************/ | |
586 | ||
587 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
588 | ||
589 | Arguments: | |
038597d2 | 590 | sctx The current SSL CTX (inbound or outbound) |
a799883d | 591 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 592 | host connected host, if client; NULL if server |
cf0c6164 | 593 | errstr error string pointer |
059ec3d9 PH |
594 | |
595 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
596 | */ | |
597 | ||
598 | static BOOL | |
cf0c6164 | 599 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr) |
059ec3d9 | 600 | { |
059ec3d9 PH |
601 | BIO *bio; |
602 | DH *dh; | |
603 | uschar *dhexpanded; | |
a799883d | 604 | const char *pem; |
6600985a | 605 | int dh_bitsize; |
059ec3d9 | 606 | |
cf0c6164 | 607 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr)) |
059ec3d9 PH |
608 | return FALSE; |
609 | ||
0df4ab80 | 610 | if (!dhexpanded || !*dhexpanded) |
a799883d | 611 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 612 | else if (dhexpanded[0] == '/') |
059ec3d9 | 613 | { |
0df4ab80 | 614 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 615 | { |
7199e1ee | 616 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
cf0c6164 | 617 | host, US strerror(errno), errstr); |
a799883d | 618 | return FALSE; |
059ec3d9 | 619 | } |
a799883d PP |
620 | } |
621 | else | |
622 | { | |
623 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 624 | { |
a799883d PP |
625 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
626 | return TRUE; | |
059ec3d9 | 627 | } |
a799883d | 628 | |
0df4ab80 | 629 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
630 | { |
631 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
cf0c6164 | 632 | host, US strerror(errno), errstr); |
a799883d PP |
633 | return FALSE; |
634 | } | |
635 | bio = BIO_new_mem_buf(CS pem, -1); | |
636 | } | |
637 | ||
0df4ab80 | 638 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 639 | { |
059ec3d9 | 640 | BIO_free(bio); |
a799883d | 641 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
cf0c6164 | 642 | host, NULL, errstr); |
a799883d PP |
643 | return FALSE; |
644 | } | |
645 | ||
6600985a PP |
646 | /* note: our default limit of 2236 is not a multiple of 8; the limit comes from |
647 | * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with | |
648 | * 2236. But older OpenSSL can only report in bytes (octets), not bits. | |
649 | * If someone wants to dance at the edge, then they can raise the limit or use | |
650 | * current libraries. */ | |
651 | #ifdef EXIM_HAVE_OPENSSL_DH_BITS | |
652 | /* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022 | |
653 | * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */ | |
654 | dh_bitsize = DH_bits(dh); | |
655 | #else | |
656 | dh_bitsize = 8 * DH_size(dh); | |
657 | #endif | |
658 | ||
a799883d PP |
659 | /* Even if it is larger, we silently return success rather than cause things |
660 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
661 | * debatable choice. */ | |
6600985a | 662 | if (dh_bitsize > tls_dh_max_bits) |
a799883d PP |
663 | { |
664 | DEBUG(D_tls) | |
170f4904 | 665 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n", |
6600985a | 666 | dh_bitsize, tls_dh_max_bits); |
a799883d PP |
667 | } |
668 | else | |
669 | { | |
670 | SSL_CTX_set_tmp_dh(sctx, dh); | |
671 | DEBUG(D_tls) | |
672 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
6600985a | 673 | dhexpanded ? dhexpanded : US"default", dh_bitsize); |
059ec3d9 PH |
674 | } |
675 | ||
a799883d PP |
676 | DH_free(dh); |
677 | BIO_free(bio); | |
678 | ||
679 | return TRUE; | |
059ec3d9 PH |
680 | } |
681 | ||
682 | ||
683 | ||
684 | ||
038597d2 PP |
685 | /************************************************* |
686 | * Initialize for ECDH * | |
687 | *************************************************/ | |
688 | ||
689 | /* Load parameters for ECDH encryption. | |
690 | ||
691 | For now, we stick to NIST P-256 because: it's simple and easy to configure; | |
692 | it avoids any patent issues that might bite redistributors; despite events in | |
693 | the news and concerns over curve choices, we're not cryptographers, we're not | |
694 | pretending to be, and this is "good enough" to be better than no support, | |
695 | protecting against most adversaries. Given another year or two, there might | |
696 | be sufficient clarity about a "right" way forward to let us make an informed | |
697 | decision, instead of a knee-jerk reaction. | |
698 | ||
699 | Longer-term, we should look at supporting both various named curves and | |
700 | external files generated with "openssl ecparam", much as we do for init_dh(). | |
701 | We should also support "none" as a value, to explicitly avoid initialisation. | |
702 | ||
703 | Patches welcome. | |
704 | ||
705 | Arguments: | |
706 | sctx The current SSL CTX (inbound or outbound) | |
707 | host connected host, if client; NULL if server | |
cf0c6164 | 708 | errstr error string pointer |
038597d2 PP |
709 | |
710 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
711 | */ | |
712 | ||
713 | static BOOL | |
cf0c6164 | 714 | init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr) |
038597d2 | 715 | { |
63f0dbe0 JH |
716 | #ifdef OPENSSL_NO_ECDH |
717 | return TRUE; | |
718 | #else | |
719 | ||
10ca4f1c JH |
720 | EC_KEY * ecdh; |
721 | uschar * exp_curve; | |
722 | int nid; | |
723 | BOOL rv; | |
724 | ||
038597d2 PP |
725 | if (host) /* No ECDH setup for clients, only for servers */ |
726 | return TRUE; | |
727 | ||
10ca4f1c | 728 | # ifndef EXIM_HAVE_ECDH |
038597d2 PP |
729 | DEBUG(D_tls) |
730 | debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); | |
731 | return TRUE; | |
038597d2 | 732 | # else |
10ca4f1c | 733 | |
cf0c6164 | 734 | if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr)) |
10ca4f1c JH |
735 | return FALSE; |
736 | if (!exp_curve || !*exp_curve) | |
737 | return TRUE; | |
738 | ||
8e53a4fc | 739 | /* "auto" needs to be handled carefully. |
4c04137d | 740 | * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1 |
8e53a4fc | 741 | * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto |
4c04137d | 742 | * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO) |
8e53a4fc HSHR |
743 | * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection |
744 | * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b | |
745 | */ | |
10ca4f1c | 746 | if (Ustrcmp(exp_curve, "auto") == 0) |
038597d2 | 747 | { |
8e53a4fc | 748 | #if OPENSSL_VERSION_NUMBER < 0x10002000L |
10ca4f1c | 749 | DEBUG(D_tls) debug_printf( |
8e53a4fc | 750 | "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n"); |
78a3bbd5 | 751 | exp_curve = US"prime256v1"; |
8e53a4fc HSHR |
752 | #else |
753 | # if defined SSL_CTRL_SET_ECDH_AUTO | |
754 | DEBUG(D_tls) debug_printf( | |
755 | "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n"); | |
10ca4f1c JH |
756 | SSL_CTX_set_ecdh_auto(sctx, 1); |
757 | return TRUE; | |
8e53a4fc HSHR |
758 | # else |
759 | DEBUG(D_tls) debug_printf( | |
760 | "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n"); | |
761 | return TRUE; | |
762 | # endif | |
763 | #endif | |
10ca4f1c | 764 | } |
038597d2 | 765 | |
10ca4f1c JH |
766 | DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve); |
767 | if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef | |
768 | # ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID | |
769 | && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef | |
770 | # endif | |
771 | ) | |
772 | { | |
cf0c6164 JH |
773 | tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve), |
774 | host, NULL, errstr); | |
10ca4f1c JH |
775 | return FALSE; |
776 | } | |
038597d2 | 777 | |
10ca4f1c JH |
778 | if (!(ecdh = EC_KEY_new_by_curve_name(nid))) |
779 | { | |
cf0c6164 | 780 | tls_error(US"Unable to create ec curve", host, NULL, errstr); |
10ca4f1c | 781 | return FALSE; |
038597d2 | 782 | } |
10ca4f1c JH |
783 | |
784 | /* The "tmp" in the name here refers to setting a temporary key | |
785 | not to the stability of the interface. */ | |
786 | ||
787 | if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) | |
cf0c6164 | 788 | tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr); |
10ca4f1c JH |
789 | else |
790 | DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); | |
791 | ||
792 | EC_KEY_free(ecdh); | |
793 | return !rv; | |
794 | ||
795 | # endif /*EXIM_HAVE_ECDH*/ | |
796 | #endif /*OPENSSL_NO_ECDH*/ | |
038597d2 PP |
797 | } |
798 | ||
799 | ||
800 | ||
801 | ||
f2de3a33 | 802 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
803 | /************************************************* |
804 | * Load OCSP information into state * | |
805 | *************************************************/ | |
f5d78688 | 806 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
807 | caller has determined this is needed. Checks validity. Debugs a message |
808 | if invalid. | |
809 | ||
810 | ASSUMES: single response, for single cert. | |
811 | ||
812 | Arguments: | |
813 | sctx the SSL_CTX* to update | |
814 | cbinfo various parts of session state | |
815 | expanded the filename putatively holding an OCSP response | |
816 | ||
817 | */ | |
818 | ||
819 | static void | |
f5d78688 | 820 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 | 821 | { |
ee5b1e28 JH |
822 | BIO * bio; |
823 | OCSP_RESPONSE * resp; | |
824 | OCSP_BASICRESP * basic_response; | |
825 | OCSP_SINGLERESP * single_response; | |
826 | ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd; | |
ee5b1e28 | 827 | STACK_OF(X509) * sk; |
3f7eeb86 PP |
828 | unsigned long verify_flags; |
829 | int status, reason, i; | |
830 | ||
f5d78688 JH |
831 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
832 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 833 | { |
f5d78688 JH |
834 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
835 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
836 | } |
837 | ||
ee5b1e28 | 838 | if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"))) |
3f7eeb86 PP |
839 | { |
840 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 841 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
842 | return; |
843 | } | |
844 | ||
845 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
846 | BIO_free(bio); | |
847 | if (!resp) | |
848 | { | |
849 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
850 | return; | |
851 | } | |
852 | ||
ee5b1e28 | 853 | if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL) |
3f7eeb86 PP |
854 | { |
855 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
856 | OCSP_response_status_str(status), status); | |
f5d78688 | 857 | goto bad; |
3f7eeb86 PP |
858 | } |
859 | ||
ee5b1e28 | 860 | if (!(basic_response = OCSP_response_get1_basic(resp))) |
3f7eeb86 PP |
861 | { |
862 | DEBUG(D_tls) | |
863 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 864 | goto bad; |
3f7eeb86 PP |
865 | } |
866 | ||
c3033f13 | 867 | sk = cbinfo->verify_stack; |
3f7eeb86 PP |
868 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ |
869 | ||
870 | /* May need to expose ability to adjust those flags? | |
871 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
872 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
873 | ||
4c04137d | 874 | /* This does a full verify on the OCSP proof before we load it for serving |
ee5b1e28 JH |
875 | up; possibly overkill - just date-checks might be nice enough. |
876 | ||
877 | OCSP_basic_verify takes a "store" arg, but does not | |
878 | use it for the chain verification, which is all we do | |
879 | when OCSP_NOVERIFY is set. The content from the wire | |
880 | "basic_response" and a cert-stack "sk" are all that is used. | |
881 | ||
c3033f13 JH |
882 | We have a stack, loaded in setup_certs() if tls_verify_certificates |
883 | was a file (not a directory, or "system"). It is unfortunate we | |
884 | cannot used the connection context store, as that would neatly | |
885 | handle the "system" case too, but there seems to be no library | |
886 | function for getting a stack from a store. | |
e3555426 | 887 | [ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ] |
c3033f13 JH |
888 | We do not free the stack since it could be needed a second time for |
889 | SNI handling. | |
890 | ||
4c04137d | 891 | Separately we might try to replace using OCSP_basic_verify() - which seems to not |
ee5b1e28 JH |
892 | be a public interface into the OpenSSL library (there's no manual entry) - |
893 | But what with? We also use OCSP_basic_verify in the client stapling callback. | |
4c04137d | 894 | And there we NEED it; we must verify that status... unless the |
ee5b1e28 JH |
895 | library does it for us anyway? */ |
896 | ||
897 | if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0) | |
3f7eeb86 | 898 | { |
ee5b1e28 JH |
899 | DEBUG(D_tls) |
900 | { | |
3f7eeb86 PP |
901 | ERR_error_string(ERR_get_error(), ssl_errstring); |
902 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); | |
f5d78688 JH |
903 | } |
904 | goto bad; | |
3f7eeb86 PP |
905 | } |
906 | ||
907 | /* Here's the simplifying assumption: there's only one response, for the | |
908 | one certificate we use, and nothing for anything else in a chain. If this | |
909 | proves false, we need to extract a cert id from our issued cert | |
910 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
911 | right cert in the stack and then calls OCSP_single_get0_status()). | |
912 | ||
913 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
ee5b1e28 JH |
914 | |
915 | if (!(single_response = OCSP_resp_get0(basic_response, 0))) | |
3f7eeb86 PP |
916 | { |
917 | DEBUG(D_tls) | |
918 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 919 | goto bad; |
3f7eeb86 PP |
920 | } |
921 | ||
922 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 923 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 924 | { |
f5d78688 JH |
925 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
926 | OCSP_cert_status_str(status), status, | |
927 | OCSP_crl_reason_str(reason), reason); | |
928 | goto bad; | |
3f7eeb86 PP |
929 | } |
930 | ||
931 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
932 | { | |
933 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 934 | goto bad; |
3f7eeb86 PP |
935 | } |
936 | ||
f5d78688 | 937 | supply_response: |
018058b2 | 938 | cbinfo->u_ocsp.server.response = resp; |
f5d78688 JH |
939 | return; |
940 | ||
941 | bad: | |
018058b2 JH |
942 | if (running_in_test_harness) |
943 | { | |
944 | extern char ** environ; | |
945 | uschar ** p; | |
bc3c7bb7 | 946 | if (environ) for (p = USS environ; *p != NULL; p++) |
018058b2 JH |
947 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) |
948 | { | |
949 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
950 | goto supply_response; | |
951 | } | |
952 | } | |
f5d78688 | 953 | return; |
3f7eeb86 | 954 | } |
f2de3a33 | 955 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
956 | |
957 | ||
958 | ||
959 | ||
23bb6982 JH |
960 | /* Create and install a selfsigned certificate, for use in server mode */ |
961 | ||
962 | static int | |
cf0c6164 | 963 | tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr) |
23bb6982 JH |
964 | { |
965 | X509 * x509 = NULL; | |
966 | EVP_PKEY * pkey; | |
967 | RSA * rsa; | |
968 | X509_NAME * name; | |
969 | uschar * where; | |
970 | ||
971 | where = US"allocating pkey"; | |
972 | if (!(pkey = EVP_PKEY_new())) | |
973 | goto err; | |
974 | ||
975 | where = US"allocating cert"; | |
976 | if (!(x509 = X509_new())) | |
977 | goto err; | |
978 | ||
979 | where = US"generating pkey"; | |
980 | /* deprecated, use RSA_generate_key_ex() */ | |
981 | if (!(rsa = RSA_generate_key(1024, RSA_F4, NULL, NULL))) | |
982 | goto err; | |
983 | ||
4c04137d | 984 | where = US"assigning pkey"; |
23bb6982 JH |
985 | if (!EVP_PKEY_assign_RSA(pkey, rsa)) |
986 | goto err; | |
987 | ||
988 | X509_set_version(x509, 2); /* N+1 - version 3 */ | |
989 | ASN1_INTEGER_set(X509_get_serialNumber(x509), 0); | |
990 | X509_gmtime_adj(X509_get_notBefore(x509), 0); | |
991 | X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60); /* 1 hour */ | |
992 | X509_set_pubkey(x509, pkey); | |
993 | ||
994 | name = X509_get_subject_name(x509); | |
995 | X509_NAME_add_entry_by_txt(name, "C", | |
4dc2379a | 996 | MBSTRING_ASC, CUS "UK", -1, -1, 0); |
23bb6982 | 997 | X509_NAME_add_entry_by_txt(name, "O", |
4dc2379a | 998 | MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0); |
23bb6982 | 999 | X509_NAME_add_entry_by_txt(name, "CN", |
4dc2379a | 1000 | MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0); |
23bb6982 JH |
1001 | X509_set_issuer_name(x509, name); |
1002 | ||
1003 | where = US"signing cert"; | |
1004 | if (!X509_sign(x509, pkey, EVP_md5())) | |
1005 | goto err; | |
1006 | ||
1007 | where = US"installing selfsign cert"; | |
1008 | if (!SSL_CTX_use_certificate(sctx, x509)) | |
1009 | goto err; | |
1010 | ||
1011 | where = US"installing selfsign key"; | |
1012 | if (!SSL_CTX_use_PrivateKey(sctx, pkey)) | |
1013 | goto err; | |
1014 | ||
1015 | return OK; | |
1016 | ||
1017 | err: | |
cf0c6164 | 1018 | (void) tls_error(where, NULL, NULL, errstr); |
23bb6982 JH |
1019 | if (x509) X509_free(x509); |
1020 | if (pkey) EVP_PKEY_free(pkey); | |
1021 | return DEFER; | |
1022 | } | |
1023 | ||
1024 | ||
1025 | ||
1026 | ||
7be682ca PP |
1027 | /************************************************* |
1028 | * Expand key and cert file specs * | |
1029 | *************************************************/ | |
1030 | ||
f5d78688 | 1031 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
1032 | new context, if Server Name Indication was used and tls_sni was seen in |
1033 | the certificate string. | |
1034 | ||
1035 | Arguments: | |
1036 | sctx the SSL_CTX* to update | |
1037 | cbinfo various parts of session state | |
cf0c6164 | 1038 | errstr error string pointer |
7be682ca PP |
1039 | |
1040 | Returns: OK/DEFER/FAIL | |
1041 | */ | |
1042 | ||
1043 | static int | |
cf0c6164 JH |
1044 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, |
1045 | uschar ** errstr) | |
7be682ca PP |
1046 | { |
1047 | uschar *expanded; | |
1048 | ||
23bb6982 | 1049 | if (!cbinfo->certificate) |
7be682ca | 1050 | { |
23bb6982 JH |
1051 | if (cbinfo->host) /* client */ |
1052 | return OK; | |
1053 | /* server */ | |
cf0c6164 | 1054 | if (tls_install_selfsign(sctx, errstr) != OK) |
23bb6982 | 1055 | return DEFER; |
7be682ca | 1056 | } |
23bb6982 JH |
1057 | else |
1058 | { | |
1059 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || | |
1060 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
1061 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
1062 | ) | |
1063 | reexpand_tls_files_for_sni = TRUE; | |
7be682ca | 1064 | |
cf0c6164 | 1065 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr)) |
23bb6982 JH |
1066 | return DEFER; |
1067 | ||
1068 | if (expanded != NULL) | |
1069 | { | |
1070 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); | |
1071 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) | |
1072 | return tls_error(string_sprintf( | |
1073 | "SSL_CTX_use_certificate_chain_file file=%s", expanded), | |
cf0c6164 | 1074 | cbinfo->host, NULL, errstr); |
23bb6982 | 1075 | } |
7be682ca | 1076 | |
23bb6982 | 1077 | if (cbinfo->privatekey != NULL && |
cf0c6164 | 1078 | !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr)) |
23bb6982 | 1079 | return DEFER; |
7be682ca | 1080 | |
23bb6982 JH |
1081 | /* If expansion was forced to fail, key_expanded will be NULL. If the result |
1082 | of the expansion is an empty string, ignore it also, and assume the private | |
1083 | key is in the same file as the certificate. */ | |
1084 | ||
1085 | if (expanded && *expanded) | |
1086 | { | |
1087 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); | |
1088 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) | |
1089 | return tls_error(string_sprintf( | |
cf0c6164 | 1090 | "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL, errstr); |
23bb6982 | 1091 | } |
7be682ca PP |
1092 | } |
1093 | ||
f2de3a33 | 1094 | #ifndef DISABLE_OCSP |
f40d5be3 | 1095 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1096 | { |
cf0c6164 | 1097 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr)) |
3f7eeb86 PP |
1098 | return DEFER; |
1099 | ||
f40d5be3 | 1100 | if (expanded && *expanded) |
3f7eeb86 PP |
1101 | { |
1102 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f40d5be3 JH |
1103 | if ( cbinfo->u_ocsp.server.file_expanded |
1104 | && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 | 1105 | { |
f40d5be3 JH |
1106 | DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n"); |
1107 | } | |
1108 | else | |
f40d5be3 | 1109 | ocsp_load_response(sctx, cbinfo, expanded); |
3f7eeb86 PP |
1110 | } |
1111 | } | |
1112 | #endif | |
1113 | ||
7be682ca PP |
1114 | return OK; |
1115 | } | |
1116 | ||
1117 | ||
1118 | ||
1119 | ||
1120 | /************************************************* | |
1121 | * Callback to handle SNI * | |
1122 | *************************************************/ | |
1123 | ||
1124 | /* Called when acting as server during the TLS session setup if a Server Name | |
1125 | Indication extension was sent by the client. | |
1126 | ||
1127 | API documentation is OpenSSL s_server.c implementation. | |
1128 | ||
1129 | Arguments: | |
1130 | s SSL* of the current session | |
1131 | ad unknown (part of OpenSSL API) (unused) | |
1132 | arg Callback of "our" registered data | |
1133 | ||
1134 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
1135 | */ | |
1136 | ||
3bcbbbe2 | 1137 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
1138 | static int |
1139 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
1140 | { | |
1141 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 1142 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 1143 | int rc; |
3f0945ff | 1144 | int old_pool = store_pool; |
cf0c6164 | 1145 | uschar * dummy_errstr; |
7be682ca PP |
1146 | |
1147 | if (!servername) | |
1148 | return SSL_TLSEXT_ERR_OK; | |
1149 | ||
3f0945ff | 1150 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
1151 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
1152 | ||
1153 | /* Make the extension value available for expansion */ | |
3f0945ff | 1154 | store_pool = POOL_PERM; |
817d9f57 | 1155 | tls_in.sni = string_copy(US servername); |
3f0945ff | 1156 | store_pool = old_pool; |
7be682ca PP |
1157 | |
1158 | if (!reexpand_tls_files_for_sni) | |
1159 | return SSL_TLSEXT_ERR_OK; | |
1160 | ||
1161 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
1162 | not confident that memcpy wouldn't break some internal reference counting. | |
1163 | Especially since there's a references struct member, which would be off. */ | |
1164 | ||
0df4ab80 | 1165 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7be682ca PP |
1166 | { |
1167 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
1168 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); | |
1169 | return SSL_TLSEXT_ERR_NOACK; | |
1170 | } | |
1171 | ||
1172 | /* Not sure how many of these are actually needed, since SSL object | |
1173 | already exists. Might even need this selfsame callback, for reneg? */ | |
1174 | ||
817d9f57 JH |
1175 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
1176 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
1177 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
1178 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
1179 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
1180 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
038597d2 | 1181 | |
cf0c6164 JH |
1182 | if ( !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr) |
1183 | || !init_ecdh(server_sni, NULL, &dummy_errstr) | |
038597d2 PP |
1184 | ) |
1185 | return SSL_TLSEXT_ERR_NOACK; | |
1186 | ||
7be682ca | 1187 | if (cbinfo->server_cipher_list) |
817d9f57 | 1188 | SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list); |
f2de3a33 | 1189 | #ifndef DISABLE_OCSP |
f5d78688 | 1190 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1191 | { |
f5d78688 | 1192 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 1193 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
1194 | } |
1195 | #endif | |
7be682ca | 1196 | |
c3033f13 | 1197 | if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, |
cf0c6164 | 1198 | verify_callback_server, &dummy_errstr)) != OK) |
c3033f13 | 1199 | return SSL_TLSEXT_ERR_NOACK; |
7be682ca | 1200 | |
3f7eeb86 PP |
1201 | /* do this after setup_certs, because this can require the certs for verifying |
1202 | OCSP information. */ | |
cf0c6164 | 1203 | if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK) |
0df4ab80 | 1204 | return SSL_TLSEXT_ERR_NOACK; |
a799883d | 1205 | |
7be682ca | 1206 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 1207 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca PP |
1208 | |
1209 | return SSL_TLSEXT_ERR_OK; | |
1210 | } | |
3bcbbbe2 | 1211 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
1212 | |
1213 | ||
1214 | ||
1215 | ||
f2de3a33 | 1216 | #ifndef DISABLE_OCSP |
f5d78688 | 1217 | |
3f7eeb86 PP |
1218 | /************************************************* |
1219 | * Callback to handle OCSP Stapling * | |
1220 | *************************************************/ | |
1221 | ||
1222 | /* Called when acting as server during the TLS session setup if the client | |
1223 | requests OCSP information with a Certificate Status Request. | |
1224 | ||
1225 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
1226 | project. | |
1227 | ||
1228 | */ | |
1229 | ||
1230 | static int | |
f5d78688 | 1231 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
1232 | { |
1233 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
1234 | uschar *response_der; | |
1235 | int response_der_len; | |
1236 | ||
af4a1bca | 1237 | DEBUG(D_tls) |
b3ef41c9 | 1238 | debug_printf("Received TLS status request (OCSP stapling); %s response\n", |
f5d78688 JH |
1239 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
1240 | ||
44662487 | 1241 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 1242 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
1243 | return SSL_TLSEXT_ERR_NOACK; |
1244 | ||
1245 | response_der = NULL; | |
44662487 JH |
1246 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, |
1247 | &response_der); | |
3f7eeb86 PP |
1248 | if (response_der_len <= 0) |
1249 | return SSL_TLSEXT_ERR_NOACK; | |
1250 | ||
5e55c7a9 | 1251 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 1252 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
1253 | return SSL_TLSEXT_ERR_OK; |
1254 | } | |
1255 | ||
3f7eeb86 | 1256 | |
f5d78688 JH |
1257 | static void |
1258 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
1259 | { | |
1260 | BIO_printf(bp, "\t%s: ", str); | |
1261 | ASN1_GENERALIZEDTIME_print(bp, time); | |
1262 | BIO_puts(bp, "\n"); | |
1263 | } | |
1264 | ||
1265 | static int | |
1266 | tls_client_stapling_cb(SSL *s, void *arg) | |
1267 | { | |
1268 | tls_ext_ctx_cb * cbinfo = arg; | |
1269 | const unsigned char * p; | |
1270 | int len; | |
1271 | OCSP_RESPONSE * rsp; | |
1272 | OCSP_BASICRESP * bs; | |
1273 | int i; | |
1274 | ||
1275 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
1276 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
1277 | if(!p) | |
1278 | { | |
44662487 | 1279 | /* Expect this when we requested ocsp but got none */ |
6c6d6e48 | 1280 | if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher)) |
44662487 | 1281 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); |
f5d78688 JH |
1282 | else |
1283 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1284 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1285 | } |
018058b2 | 1286 | |
f5d78688 JH |
1287 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
1288 | { | |
018058b2 | 1289 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1290 | if (LOGGING(tls_cipher)) |
1eca31ca | 1291 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
1292 | else |
1293 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1294 | return 0; | |
1295 | } | |
1296 | ||
1297 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
1298 | { | |
018058b2 | 1299 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1300 | if (LOGGING(tls_cipher)) |
1eca31ca | 1301 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1302 | else |
1303 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1304 | OCSP_RESPONSE_free(rsp); | |
1305 | return 0; | |
1306 | } | |
1307 | ||
1308 | /* We'd check the nonce here if we'd put one in the request. */ | |
1309 | /* However that would defeat cacheability on the server so we don't. */ | |
1310 | ||
f5d78688 JH |
1311 | /* This section of code reworked from OpenSSL apps source; |
1312 | The OpenSSL Project retains copyright: | |
1313 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1314 | */ | |
1315 | { | |
1316 | BIO * bp = NULL; | |
f5d78688 JH |
1317 | int status, reason; |
1318 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1319 | ||
1320 | DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE); | |
1321 | ||
1322 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1323 | ||
1324 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1325 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1326 | ||
c3033f13 | 1327 | if ((i = OCSP_basic_verify(bs, cbinfo->verify_stack, |
44662487 | 1328 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) |
f5d78688 | 1329 | { |
018058b2 | 1330 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1331 | if (LOGGING(tls_cipher)) |
1eca31ca | 1332 | log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable"); |
f5d78688 JH |
1333 | BIO_printf(bp, "OCSP response verify failure\n"); |
1334 | ERR_print_errors(bp); | |
c8dfb21d | 1335 | goto failed; |
f5d78688 JH |
1336 | } |
1337 | ||
1338 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1339 | ||
c8dfb21d JH |
1340 | /*XXX So we have a good stapled OCSP status. How do we know |
1341 | it is for the cert of interest? OpenSSL 1.1.0 has a routine | |
1342 | OCSP_resp_find_status() which matches on a cert id, which presumably | |
1343 | we should use. Making an id needs OCSP_cert_id_new(), which takes | |
1344 | issuerName, issuerKey, serialNumber. Are they all in the cert? | |
1345 | ||
1346 | For now, carry on blindly accepting the resp. */ | |
1347 | ||
f5d78688 | 1348 | { |
f5d78688 JH |
1349 | OCSP_SINGLERESP * single; |
1350 | ||
c8dfb21d JH |
1351 | #ifdef EXIM_HAVE_OCSP_RESP_COUNT |
1352 | if (OCSP_resp_count(bs) != 1) | |
1353 | #else | |
1354 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
f5d78688 | 1355 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) |
c8dfb21d | 1356 | #endif |
f5d78688 | 1357 | { |
018058b2 | 1358 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1359 | log_write(0, LOG_MAIN, "OCSP stapling " |
1360 | "with multiple responses not handled"); | |
c8dfb21d | 1361 | goto failed; |
f5d78688 JH |
1362 | } |
1363 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1364 | status = OCSP_single_get0_status(single, &reason, &rev, |
1365 | &thisupd, &nextupd); | |
f5d78688 JH |
1366 | } |
1367 | ||
f5d78688 JH |
1368 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1369 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1370 | if (!OCSP_check_validity(thisupd, nextupd, |
1371 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1372 | { |
018058b2 | 1373 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1374 | DEBUG(D_tls) ERR_print_errors(bp); |
1375 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
f5d78688 | 1376 | } |
44662487 | 1377 | else |
f5d78688 | 1378 | { |
44662487 JH |
1379 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1380 | OCSP_cert_status_str(status)); | |
1381 | switch(status) | |
1382 | { | |
1383 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1384 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1385 | i = 1; |
c8dfb21d | 1386 | goto good; |
44662487 | 1387 | case V_OCSP_CERTSTATUS_REVOKED: |
018058b2 | 1388 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1389 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1390 | reason != -1 ? "; reason: " : "", | |
1391 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1392 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
44662487 JH |
1393 | break; |
1394 | default: | |
018058b2 | 1395 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1396 | log_write(0, LOG_MAIN, |
1397 | "Server certificate status unknown, in OCSP stapling"); | |
44662487 JH |
1398 | break; |
1399 | } | |
f5d78688 | 1400 | } |
c8dfb21d JH |
1401 | failed: |
1402 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1403 | good: | |
f5d78688 JH |
1404 | BIO_free(bp); |
1405 | } | |
1406 | ||
1407 | OCSP_RESPONSE_free(rsp); | |
1408 | return i; | |
1409 | } | |
f2de3a33 | 1410 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1411 | |
1412 | ||
059ec3d9 PH |
1413 | /************************************************* |
1414 | * Initialize for TLS * | |
1415 | *************************************************/ | |
1416 | ||
e51c7be2 JH |
1417 | /* Called from both server and client code, to do preliminary initialization |
1418 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1419 | |
1420 | Arguments: | |
946ecbe0 | 1421 | ctxp returned SSL context |
059ec3d9 PH |
1422 | host connected host, if client; NULL if server |
1423 | dhparam DH parameter file | |
1424 | certificate certificate file | |
1425 | privatekey private key | |
f5d78688 | 1426 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1427 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1428 | cbp place to put allocated callback context |
cf0c6164 | 1429 | errstr error string pointer |
059ec3d9 PH |
1430 | |
1431 | Returns: OK/DEFER/FAIL | |
1432 | */ | |
1433 | ||
1434 | static int | |
817d9f57 | 1435 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1436 | uschar *privatekey, |
f2de3a33 | 1437 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1438 | uschar *ocsp_file, |
1439 | #endif | |
cf0c6164 | 1440 | address_item *addr, tls_ext_ctx_cb ** cbp, uschar ** errstr) |
059ec3d9 | 1441 | { |
7006ee24 | 1442 | SSL_CTX * ctx; |
77bb000f | 1443 | long init_options; |
7be682ca | 1444 | int rc; |
a7538db1 | 1445 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1446 | |
1447 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1448 | cbinfo->certificate = certificate; | |
1449 | cbinfo->privatekey = privatekey; | |
f2de3a33 | 1450 | #ifndef DISABLE_OCSP |
c3033f13 | 1451 | cbinfo->verify_stack = NULL; |
f5d78688 JH |
1452 | if ((cbinfo->is_server = host==NULL)) |
1453 | { | |
1454 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1455 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1456 | cbinfo->u_ocsp.server.response = NULL; | |
1457 | } | |
1458 | else | |
1459 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1460 | #endif |
7be682ca | 1461 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1462 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1463 | cbinfo->host = host; |
0cbf2b82 | 1464 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1465 | cbinfo->event_action = NULL; |
1466 | #endif | |
77bb000f | 1467 | |
059ec3d9 PH |
1468 | SSL_load_error_strings(); /* basic set up */ |
1469 | OpenSSL_add_ssl_algorithms(); | |
1470 | ||
c8dfb21d | 1471 | #ifdef EXIM_HAVE_SHA256 |
77bb000f | 1472 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1473 | list of available digests. */ |
1474 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1475 | #endif |
a0475b69 | 1476 | |
f0f5a555 PP |
1477 | /* Create a context. |
1478 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1479 | negotiation in the different methods; as far as I can tell, the only | |
1480 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1481 | when OpenSSL is built without SSLv2 support. | |
1482 | By disabling with openssl_options, we can let admins re-enable with the | |
1483 | existing knob. */ | |
059ec3d9 | 1484 | |
7006ee24 JH |
1485 | if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method()))) |
1486 | return tls_error(US"SSL_CTX_new", host, NULL, errstr); | |
059ec3d9 PH |
1487 | |
1488 | /* It turns out that we need to seed the random number generator this early in | |
1489 | order to get the full complement of ciphers to work. It took me roughly a day | |
1490 | of work to discover this by experiment. | |
1491 | ||
1492 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1493 | there. Otherwise, we have to make something up as best we can. Double check | |
1494 | afterwards. */ | |
1495 | ||
1496 | if (!RAND_status()) | |
1497 | { | |
1498 | randstuff r; | |
9e3331ea | 1499 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1500 | r.p = getpid(); |
1501 | ||
5903c6ff JH |
1502 | RAND_seed(US (&r), sizeof(r)); |
1503 | RAND_seed(US big_buffer, big_buffer_size); | |
1504 | if (addr != NULL) RAND_seed(US addr, sizeof(addr)); | |
059ec3d9 PH |
1505 | |
1506 | if (!RAND_status()) | |
7199e1ee | 1507 | return tls_error(US"RAND_status", host, |
cf0c6164 | 1508 | US"unable to seed random number generator", errstr); |
059ec3d9 PH |
1509 | } |
1510 | ||
1511 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1512 | level. */ | |
1513 | ||
7006ee24 | 1514 | DEBUG(D_tls) SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); |
059ec3d9 | 1515 | |
c80c5570 | 1516 | /* Automatically re-try reads/writes after renegotiation. */ |
7006ee24 | 1517 | (void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1518 | |
77bb000f PP |
1519 | /* Apply administrator-supplied work-arounds. |
1520 | Historically we applied just one requested option, | |
1521 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1522 | moved to an administrator-controlled list of options to specify and | |
1523 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1524 | |
77bb000f PP |
1525 | No OpenSSL version number checks: the options we accept depend upon the |
1526 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1527 | |
7006ee24 | 1528 | if (!tls_openssl_options_parse(openssl_options, &init_options)) |
cf0c6164 | 1529 | return tls_error(US"openssl_options parsing failed", host, NULL, errstr); |
77bb000f PP |
1530 | |
1531 | if (init_options) | |
1532 | { | |
1533 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
7006ee24 | 1534 | if (!(SSL_CTX_set_options(ctx, init_options))) |
77bb000f | 1535 | return tls_error(string_sprintf( |
cf0c6164 | 1536 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL, errstr); |
77bb000f PP |
1537 | } |
1538 | else | |
1539 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 | 1540 | |
7006ee24 JH |
1541 | /* Disable session cache unconditionally */ |
1542 | ||
1543 | (void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF); | |
1544 | ||
059ec3d9 | 1545 | /* Initialize with DH parameters if supplied */ |
10ca4f1c | 1546 | /* Initialize ECDH temp key parameter selection */ |
059ec3d9 | 1547 | |
7006ee24 JH |
1548 | if ( !init_dh(ctx, dhparam, host, errstr) |
1549 | || !init_ecdh(ctx, host, errstr) | |
038597d2 PP |
1550 | ) |
1551 | return DEFER; | |
059ec3d9 | 1552 | |
3f7eeb86 | 1553 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1554 | |
7006ee24 | 1555 | if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK) |
23bb6982 | 1556 | return rc; |
c91535f3 | 1557 | |
c3033f13 JH |
1558 | /* If we need to handle SNI or OCSP, do so */ |
1559 | ||
3bcbbbe2 | 1560 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
c3033f13 JH |
1561 | # ifndef DISABLE_OCSP |
1562 | if (!(cbinfo->verify_stack = sk_X509_new_null())) | |
1563 | { | |
1564 | DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n"); | |
1565 | return FAIL; | |
1566 | } | |
1567 | # endif | |
1568 | ||
f5d78688 | 1569 | if (host == NULL) /* server */ |
3f0945ff | 1570 | { |
f2de3a33 | 1571 | # ifndef DISABLE_OCSP |
f5d78688 | 1572 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1573 | the option exists, not what the current expansion might be, as SNI might |
1574 | change the certificate and OCSP file in use between now and the time the | |
1575 | callback is invoked. */ | |
f5d78688 | 1576 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1577 | { |
7006ee24 JH |
1578 | SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb); |
1579 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
3f7eeb86 | 1580 | } |
f5d78688 | 1581 | # endif |
3f0945ff PP |
1582 | /* We always do this, so that $tls_sni is available even if not used in |
1583 | tls_certificate */ | |
7006ee24 JH |
1584 | SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); |
1585 | SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo); | |
3f0945ff | 1586 | } |
f2de3a33 | 1587 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1588 | else /* client */ |
1589 | if(ocsp_file) /* wanting stapling */ | |
1590 | { | |
1591 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1592 | { | |
1593 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1594 | return FAIL; | |
1595 | } | |
7006ee24 JH |
1596 | SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb); |
1597 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
f5d78688 JH |
1598 | } |
1599 | # endif | |
7be682ca | 1600 | #endif |
059ec3d9 | 1601 | |
e51c7be2 | 1602 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 1603 | |
c8dfb21d | 1604 | #ifdef EXIM_HAVE_EPHEM_RSA_KEX |
059ec3d9 | 1605 | /* Set up the RSA callback */ |
7006ee24 | 1606 | SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); |
c8dfb21d | 1607 | #endif |
059ec3d9 PH |
1608 | |
1609 | /* Finally, set the timeout, and we are done */ | |
1610 | ||
7006ee24 | 1611 | SSL_CTX_set_timeout(ctx, ssl_session_timeout); |
059ec3d9 | 1612 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1613 | |
817d9f57 | 1614 | *cbp = cbinfo; |
7006ee24 | 1615 | *ctxp = ctx; |
7be682ca | 1616 | |
059ec3d9 PH |
1617 | return OK; |
1618 | } | |
1619 | ||
1620 | ||
1621 | ||
1622 | ||
1623 | /************************************************* | |
1624 | * Get name of cipher in use * | |
1625 | *************************************************/ | |
1626 | ||
817d9f57 | 1627 | /* |
059ec3d9 | 1628 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1629 | buffer to use for answer |
1630 | size of buffer | |
1631 | pointer to number of bits for cipher | |
059ec3d9 PH |
1632 | Returns: nothing |
1633 | */ | |
1634 | ||
1635 | static void | |
817d9f57 | 1636 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1637 | { |
57b3a7f5 PP |
1638 | /* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't |
1639 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have | |
1640 | the accessor functions use const in the prototype. */ | |
1641 | const SSL_CIPHER *c; | |
d9784128 | 1642 | const uschar *ver; |
059ec3d9 | 1643 | |
d9784128 | 1644 | ver = (const uschar *)SSL_get_version(ssl); |
059ec3d9 | 1645 | |
57b3a7f5 | 1646 | c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); |
817d9f57 | 1647 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1648 | |
817d9f57 JH |
1649 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1650 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1651 | |
1652 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1653 | } | |
1654 | ||
1655 | ||
f69979cf JH |
1656 | static void |
1657 | peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned bsize) | |
1658 | { | |
1659 | /*XXX we might consider a list-of-certs variable for the cert chain. | |
1660 | SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support | |
1661 | in list-handling functions, also consider the difference between the entire | |
1662 | chain and the elements sent by the peer. */ | |
1663 | ||
1664 | /* Will have already noted peercert on a verify fail; possibly not the leaf */ | |
1665 | if (!tlsp->peercert) | |
1666 | tlsp->peercert = SSL_get_peer_certificate(ssl); | |
1667 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
1668 | if (tlsp->peercert) | |
1669 | { | |
1670 | X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, bsize); | |
1671 | peerdn[bsize-1] = '\0'; | |
1672 | tlsp->peerdn = peerdn; /*XXX a static buffer... */ | |
1673 | } | |
1674 | else | |
1675 | tlsp->peerdn = NULL; | |
1676 | } | |
1677 | ||
1678 | ||
059ec3d9 PH |
1679 | |
1680 | ||
1681 | ||
1682 | /************************************************* | |
1683 | * Set up for verifying certificates * | |
1684 | *************************************************/ | |
1685 | ||
c3033f13 JH |
1686 | /* Load certs from file, return TRUE on success */ |
1687 | ||
1688 | static BOOL | |
1689 | chain_from_pem_file(const uschar * file, STACK_OF(X509) * verify_stack) | |
1690 | { | |
1691 | BIO * bp; | |
1692 | X509 * x; | |
1693 | ||
1694 | if (!(bp = BIO_new_file(CS file, "r"))) return FALSE; | |
1695 | while ((x = PEM_read_bio_X509(bp, NULL, 0, NULL))) | |
1696 | sk_X509_push(verify_stack, x); | |
1697 | BIO_free(bp); | |
1698 | return TRUE; | |
1699 | } | |
1700 | ||
1701 | ||
1702 | ||
059ec3d9 PH |
1703 | /* Called by both client and server startup |
1704 | ||
1705 | Arguments: | |
7be682ca | 1706 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1707 | certs certs file or NULL |
1708 | crl CRL file or NULL | |
1709 | host NULL in a server; the remote host in a client | |
1710 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1711 | otherwise passed as FALSE | |
983207c1 | 1712 | cert_vfy_cb Callback function for certificate verification |
cf0c6164 | 1713 | errstr error string pointer |
059ec3d9 PH |
1714 | |
1715 | Returns: OK/DEFER/FAIL | |
1716 | */ | |
1717 | ||
1718 | static int | |
983207c1 | 1719 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 1720 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr) |
059ec3d9 PH |
1721 | { |
1722 | uschar *expcerts, *expcrl; | |
1723 | ||
cf0c6164 | 1724 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts, errstr)) |
059ec3d9 | 1725 | return DEFER; |
57cc2785 | 1726 | DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts); |
059ec3d9 | 1727 | |
10a831a3 | 1728 | if (expcerts && *expcerts) |
059ec3d9 | 1729 | { |
10a831a3 JH |
1730 | /* Tell the library to use its compiled-in location for the system default |
1731 | CA bundle. Then add the ones specified in the config, if any. */ | |
cb1d7830 | 1732 | |
10a831a3 | 1733 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
cf0c6164 | 1734 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr); |
10a831a3 JH |
1735 | |
1736 | if (Ustrcmp(expcerts, "system") != 0) | |
059ec3d9 | 1737 | { |
cb1d7830 JH |
1738 | struct stat statbuf; |
1739 | ||
cb1d7830 JH |
1740 | if (Ustat(expcerts, &statbuf) < 0) |
1741 | { | |
1742 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1743 | "failed to stat %s for certificates", expcerts); | |
1744 | return DEFER; | |
1745 | } | |
059ec3d9 | 1746 | else |
059ec3d9 | 1747 | { |
cb1d7830 JH |
1748 | uschar *file, *dir; |
1749 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1750 | { file = NULL; dir = expcerts; } | |
1751 | else | |
c3033f13 JH |
1752 | { |
1753 | file = expcerts; dir = NULL; | |
1754 | #ifndef DISABLE_OCSP | |
1755 | /* In the server if we will be offering an OCSP proof, load chain from | |
1756 | file for verifying the OCSP proof at load time. */ | |
1757 | ||
1758 | if ( !host | |
1759 | && statbuf.st_size > 0 | |
1760 | && server_static_cbinfo->u_ocsp.server.file | |
1761 | && !chain_from_pem_file(file, server_static_cbinfo->verify_stack) | |
1762 | ) | |
1763 | { | |
1764 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1765 | "failed to load cert hain from %s", file); | |
1766 | return DEFER; | |
1767 | } | |
1768 | #endif | |
1769 | } | |
cb1d7830 JH |
1770 | |
1771 | /* If a certificate file is empty, the next function fails with an | |
1772 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
1773 | certificates are recognized, but the error message is still misleading (it | |
c3033f13 | 1774 | says no certificate was supplied). But this is better. */ |
cb1d7830 | 1775 | |
f2f2c91b JH |
1776 | if ( (!file || statbuf.st_size > 0) |
1777 | && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
cf0c6164 | 1778 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr); |
cb1d7830 JH |
1779 | |
1780 | /* Load the list of CAs for which we will accept certs, for sending | |
1781 | to the client. This is only for the one-file tls_verify_certificates | |
1782 | variant. | |
1783 | If a list isn't loaded into the server, but | |
1784 | some verify locations are set, the server end appears to make | |
4c04137d | 1785 | a wildcard request for client certs. |
10a831a3 | 1786 | Meanwhile, the client library as default behaviour *ignores* the list |
cb1d7830 JH |
1787 | we send over the wire - see man SSL_CTX_set_client_cert_cb. |
1788 | Because of this, and that the dir variant is likely only used for | |
1789 | the public-CA bundle (not for a private CA), not worth fixing. | |
1790 | */ | |
f2f2c91b | 1791 | if (file) |
cb1d7830 JH |
1792 | { |
1793 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); | |
f2f2c91b JH |
1794 | |
1795 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", | |
cb1d7830 JH |
1796 | sk_X509_NAME_num(names)); |
1797 | SSL_CTX_set_client_CA_list(sctx, names); | |
1798 | } | |
059ec3d9 PH |
1799 | } |
1800 | } | |
1801 | ||
1802 | /* Handle a certificate revocation list. */ | |
1803 | ||
10a831a3 | 1804 | #if OPENSSL_VERSION_NUMBER > 0x00907000L |
059ec3d9 | 1805 | |
8b417f2c | 1806 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
10a831a3 | 1807 | merely reformatted it into the Exim code style.) |
8b417f2c | 1808 | |
10a831a3 JH |
1809 | "From here I changed the code to add support for multiple crl's |
1810 | in pem format in one file or to support hashed directory entries in | |
1811 | pem format instead of a file. This method now uses the library function | |
1812 | X509_STORE_load_locations to add the CRL location to the SSL context. | |
1813 | OpenSSL will then handle the verify against CA certs and CRLs by | |
1814 | itself in the verify callback." */ | |
8b417f2c | 1815 | |
cf0c6164 | 1816 | if (!expand_check(crl, US"tls_crl", &expcrl, errstr)) return DEFER; |
10a831a3 | 1817 | if (expcrl && *expcrl) |
059ec3d9 | 1818 | { |
8b417f2c PH |
1819 | struct stat statbufcrl; |
1820 | if (Ustat(expcrl, &statbufcrl) < 0) | |
1821 | { | |
1822 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1823 | "failed to stat %s for certificates revocation lists", expcrl); | |
1824 | return DEFER; | |
1825 | } | |
1826 | else | |
059ec3d9 | 1827 | { |
8b417f2c PH |
1828 | /* is it a file or directory? */ |
1829 | uschar *file, *dir; | |
7be682ca | 1830 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 1831 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 1832 | { |
8b417f2c PH |
1833 | file = NULL; |
1834 | dir = expcrl; | |
1835 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
1836 | } |
1837 | else | |
1838 | { | |
8b417f2c PH |
1839 | file = expcrl; |
1840 | dir = NULL; | |
1841 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 1842 | } |
8b417f2c | 1843 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
cf0c6164 | 1844 | return tls_error(US"X509_STORE_load_locations", host, NULL, errstr); |
8b417f2c PH |
1845 | |
1846 | /* setting the flags to check against the complete crl chain */ | |
1847 | ||
1848 | X509_STORE_set_flags(cvstore, | |
1849 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 1850 | } |
059ec3d9 PH |
1851 | } |
1852 | ||
10a831a3 | 1853 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ |
059ec3d9 PH |
1854 | |
1855 | /* If verification is optional, don't fail if no certificate */ | |
1856 | ||
7be682ca | 1857 | SSL_CTX_set_verify(sctx, |
059ec3d9 | 1858 | SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 1859 | cert_vfy_cb); |
059ec3d9 PH |
1860 | } |
1861 | ||
1862 | return OK; | |
1863 | } | |
1864 | ||
1865 | ||
1866 | ||
1867 | /************************************************* | |
1868 | * Start a TLS session in a server * | |
1869 | *************************************************/ | |
1870 | ||
1871 | /* This is called when Exim is running as a server, after having received | |
1872 | the STARTTLS command. It must respond to that command, and then negotiate | |
1873 | a TLS session. | |
1874 | ||
1875 | Arguments: | |
1876 | require_ciphers allowed ciphers | |
cf0c6164 | 1877 | errstr pointer to error message |
059ec3d9 PH |
1878 | |
1879 | Returns: OK on success | |
1880 | DEFER for errors before the start of the negotiation | |
4c04137d | 1881 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
1882 | continue running. |
1883 | */ | |
1884 | ||
1885 | int | |
cf0c6164 | 1886 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
1887 | { |
1888 | int rc; | |
cf0c6164 JH |
1889 | uschar * expciphers; |
1890 | tls_ext_ctx_cb * cbinfo; | |
f69979cf | 1891 | static uschar peerdn[256]; |
817d9f57 | 1892 | static uschar cipherbuf[256]; |
059ec3d9 PH |
1893 | |
1894 | /* Check for previous activation */ | |
1895 | ||
817d9f57 | 1896 | if (tls_in.active >= 0) |
059ec3d9 | 1897 | { |
cf0c6164 | 1898 | tls_error(US"STARTTLS received after TLS started", NULL, US"", errstr); |
925ac8e4 | 1899 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
1900 | return FAIL; |
1901 | } | |
1902 | ||
1903 | /* Initialize the SSL library. If it fails, it will already have logged | |
1904 | the error. */ | |
1905 | ||
817d9f57 | 1906 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 1907 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1908 | tls_ocsp_file, |
1909 | #endif | |
cf0c6164 | 1910 | NULL, &server_static_cbinfo, errstr); |
059ec3d9 | 1911 | if (rc != OK) return rc; |
817d9f57 | 1912 | cbinfo = server_static_cbinfo; |
059ec3d9 | 1913 | |
cf0c6164 | 1914 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr)) |
059ec3d9 PH |
1915 | return FAIL; |
1916 | ||
1917 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
1918 | were historically separated by underscores. So that I can use either form in my |
1919 | tests, and also for general convenience, we turn underscores into hyphens here. | |
1920 | */ | |
059ec3d9 | 1921 | |
c3033f13 | 1922 | if (expciphers) |
059ec3d9 | 1923 | { |
c3033f13 | 1924 | uschar * s = expciphers; |
059ec3d9 PH |
1925 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } |
1926 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 1927 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
cf0c6164 | 1928 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr); |
7be682ca | 1929 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
1930 | } |
1931 | ||
1932 | /* If this is a host for which certificate verification is mandatory or | |
1933 | optional, set up appropriately. */ | |
1934 | ||
817d9f57 | 1935 | tls_in.certificate_verified = FALSE; |
53a7196b JH |
1936 | #ifdef EXPERIMENTAL_DANE |
1937 | tls_in.dane_verified = FALSE; | |
1938 | #endif | |
a2ff477a | 1939 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
1940 | |
1941 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1942 | { | |
983207c1 | 1943 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
cf0c6164 | 1944 | FALSE, verify_callback_server, errstr); |
059ec3d9 | 1945 | if (rc != OK) return rc; |
a2ff477a | 1946 | server_verify_optional = FALSE; |
059ec3d9 PH |
1947 | } |
1948 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1949 | { | |
983207c1 | 1950 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
cf0c6164 | 1951 | TRUE, verify_callback_server, errstr); |
059ec3d9 | 1952 | if (rc != OK) return rc; |
a2ff477a | 1953 | server_verify_optional = TRUE; |
059ec3d9 PH |
1954 | } |
1955 | ||
1956 | /* Prepare for new connection */ | |
1957 | ||
cf0c6164 JH |
1958 | if (!(server_ssl = SSL_new(server_ctx))) |
1959 | return tls_error(US"SSL_new", NULL, NULL, errstr); | |
da3ad30d PP |
1960 | |
1961 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
1962 | * | |
1963 | * With the SSL_clear(), we get strange interoperability bugs with | |
1964 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
1965 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
1966 | * | |
1967 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
1968 | * session shutdown. In this case, we have a brand new object and there's no | |
1969 | * obvious reason to immediately clear it. I'm guessing that this was | |
1970 | * originally added because of incomplete initialisation which the clear fixed, | |
1971 | * in some historic release. | |
1972 | */ | |
059ec3d9 PH |
1973 | |
1974 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1975 | on connection, where outputting anything now upsets the clients and tends to | |
1976 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1977 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1978 | mode, the fflush() happens when smtp_getc() is called. */ | |
1979 | ||
817d9f57 JH |
1980 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
1981 | if (!tls_in.on_connect) | |
059ec3d9 | 1982 | { |
925ac8e4 | 1983 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
059ec3d9 PH |
1984 | fflush(smtp_out); |
1985 | } | |
1986 | ||
1987 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1988 | that the OpenSSL library doesn't. */ | |
1989 | ||
817d9f57 JH |
1990 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
1991 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
1992 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
1993 | |
1994 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
1995 | ||
1996 | sigalrm_seen = FALSE; | |
1997 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
817d9f57 | 1998 | rc = SSL_accept(server_ssl); |
059ec3d9 PH |
1999 | alarm(0); |
2000 | ||
2001 | if (rc <= 0) | |
2002 | { | |
cf0c6164 | 2003 | (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr); |
059ec3d9 PH |
2004 | return FAIL; |
2005 | } | |
2006 | ||
2007 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
2008 | ||
2009 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2010 | and initialize things. */ | |
2011 | ||
f69979cf JH |
2012 | peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn)); |
2013 | ||
817d9f57 JH |
2014 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
2015 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
2016 | |
2017 | DEBUG(D_tls) | |
2018 | { | |
2019 | uschar buf[2048]; | |
817d9f57 | 2020 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
2021 | debug_printf("Shared ciphers: %s\n", buf); |
2022 | } | |
2023 | ||
9d1c15ef JH |
2024 | /* Record the certificate we presented */ |
2025 | { | |
2026 | X509 * crt = SSL_get_certificate(server_ssl); | |
2027 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
2028 | } | |
059ec3d9 | 2029 | |
817d9f57 JH |
2030 | /* Only used by the server-side tls (tls_in), including tls_getc. |
2031 | Client-side (tls_out) reads (seem to?) go via | |
2032 | smtp_read_response()/ip_recv(). | |
2033 | Hence no need to duplicate for _in and _out. | |
2034 | */ | |
059ec3d9 PH |
2035 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
2036 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
2037 | ssl_xfer_eof = ssl_xfer_error = 0; | |
2038 | ||
2039 | receive_getc = tls_getc; | |
0d81dabc | 2040 | receive_getbuf = tls_getbuf; |
584e96c6 | 2041 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2042 | receive_ungetc = tls_ungetc; |
2043 | receive_feof = tls_feof; | |
2044 | receive_ferror = tls_ferror; | |
58eb016e | 2045 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2046 | |
817d9f57 | 2047 | tls_in.active = fileno(smtp_out); |
059ec3d9 PH |
2048 | return OK; |
2049 | } | |
2050 | ||
2051 | ||
2052 | ||
2053 | ||
043b1248 JH |
2054 | static int |
2055 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
cf0c6164 JH |
2056 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo, |
2057 | uschar ** errstr) | |
043b1248 JH |
2058 | { |
2059 | int rc; | |
94431adb | 2060 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
043b1248 JH |
2061 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only |
2062 | the specified host patterns if one of them is defined */ | |
2063 | ||
610ff438 JH |
2064 | if ( ( !ob->tls_verify_hosts |
2065 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2066 | ) | |
5130845b | 2067 | || (verify_check_given_host(&ob->tls_verify_hosts, host) == OK) |
aa2a70ba | 2068 | ) |
043b1248 | 2069 | client_verify_optional = FALSE; |
5130845b | 2070 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
2071 | client_verify_optional = TRUE; |
2072 | else | |
2073 | return OK; | |
2074 | ||
2075 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
cf0c6164 JH |
2076 | ob->tls_crl, host, client_verify_optional, verify_callback_client, |
2077 | errstr)) != OK) | |
aa2a70ba | 2078 | return rc; |
043b1248 | 2079 | |
5130845b | 2080 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 2081 | { |
4af0d74a | 2082 | cbinfo->verify_cert_hostnames = |
8c5d388a | 2083 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2084 | string_domain_utf8_to_alabel(host->name, NULL); |
2085 | #else | |
2086 | host->name; | |
2087 | #endif | |
aa2a70ba JH |
2088 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", |
2089 | cbinfo->verify_cert_hostnames); | |
043b1248 | 2090 | } |
043b1248 JH |
2091 | return OK; |
2092 | } | |
059ec3d9 | 2093 | |
fde080a4 JH |
2094 | |
2095 | #ifdef EXPERIMENTAL_DANE | |
fde080a4 | 2096 | static int |
cf0c6164 | 2097 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa, uschar ** errstr) |
fde080a4 JH |
2098 | { |
2099 | dns_record * rr; | |
2100 | dns_scan dnss; | |
2101 | const char * hostnames[2] = { CS host->name, NULL }; | |
2102 | int found = 0; | |
2103 | ||
2104 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
cf0c6164 | 2105 | return tls_error(US"hostnames load", host, NULL, errstr); |
fde080a4 JH |
2106 | |
2107 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); | |
2108 | rr; | |
2109 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
2110 | ) if (rr->type == T_TLSA) | |
2111 | { | |
c3033f13 | 2112 | const uschar * p = rr->data; |
fde080a4 JH |
2113 | uint8_t usage, selector, mtype; |
2114 | const char * mdname; | |
2115 | ||
fde080a4 | 2116 | usage = *p++; |
133d2546 JH |
2117 | |
2118 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
2119 | if (usage != 2 && usage != 3) continue; | |
2120 | ||
fde080a4 JH |
2121 | selector = *p++; |
2122 | mtype = *p++; | |
2123 | ||
2124 | switch (mtype) | |
2125 | { | |
133d2546 JH |
2126 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
2127 | case 0: mdname = NULL; break; | |
2128 | case 1: mdname = "sha256"; break; | |
2129 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
2130 | } |
2131 | ||
133d2546 | 2132 | found++; |
fde080a4 JH |
2133 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
2134 | { | |
2135 | default: | |
cf0c6164 | 2136 | return tls_error(US"tlsa load", host, NULL, errstr); |
c035b645 | 2137 | case 0: /* action not taken */ |
fde080a4 JH |
2138 | case 1: break; |
2139 | } | |
594706ea JH |
2140 | |
2141 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
2142 | } |
2143 | ||
2144 | if (found) | |
2145 | return OK; | |
2146 | ||
133d2546 | 2147 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 2148 | return DEFER; |
fde080a4 JH |
2149 | } |
2150 | #endif /*EXPERIMENTAL_DANE*/ | |
2151 | ||
2152 | ||
2153 | ||
059ec3d9 PH |
2154 | /************************************************* |
2155 | * Start a TLS session in a client * | |
2156 | *************************************************/ | |
2157 | ||
2158 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2159 | ||
2160 | Argument: | |
2161 | fd the fd of the connection | |
2162 | host connected host (for messages) | |
83da1223 | 2163 | addr the first address |
a7538db1 | 2164 | tb transport (always smtp) |
0e66b3b6 | 2165 | tlsa_dnsa tlsa lookup, if DANE, else null |
cf0c6164 | 2166 | errstr error string pointer |
059ec3d9 PH |
2167 | |
2168 | Returns: OK on success | |
2169 | FAIL otherwise - note that tls_error() will not give DEFER | |
2170 | because this is not a server | |
2171 | */ | |
2172 | ||
2173 | int | |
f5d78688 | 2174 | tls_client_start(int fd, host_item *host, address_item *addr, |
cf0c6164 | 2175 | transport_instance * tb, |
0e66b3b6 | 2176 | #ifdef EXPERIMENTAL_DANE |
cf0c6164 | 2177 | dns_answer * tlsa_dnsa, |
0e66b3b6 | 2178 | #endif |
cf0c6164 | 2179 | uschar ** errstr) |
059ec3d9 | 2180 | { |
a7538db1 JH |
2181 | smtp_transport_options_block * ob = |
2182 | (smtp_transport_options_block *)tb->options_block; | |
f69979cf | 2183 | static uschar peerdn[256]; |
868f5672 | 2184 | uschar * expciphers; |
059ec3d9 | 2185 | int rc; |
817d9f57 | 2186 | static uschar cipherbuf[256]; |
043b1248 JH |
2187 | |
2188 | #ifndef DISABLE_OCSP | |
043b1248 | 2189 | BOOL request_ocsp = FALSE; |
6634ac8d | 2190 | BOOL require_ocsp = FALSE; |
043b1248 | 2191 | #endif |
043b1248 JH |
2192 | |
2193 | #ifdef EXPERIMENTAL_DANE | |
594706ea | 2194 | tls_out.tlsa_usage = 0; |
043b1248 JH |
2195 | #endif |
2196 | ||
f2de3a33 | 2197 | #ifndef DISABLE_OCSP |
043b1248 | 2198 | { |
4f59c424 JH |
2199 | # ifdef EXPERIMENTAL_DANE |
2200 | if ( tlsa_dnsa | |
2201 | && ob->hosts_request_ocsp[0] == '*' | |
2202 | && ob->hosts_request_ocsp[1] == '\0' | |
2203 | ) | |
2204 | { | |
2205 | /* Unchanged from default. Use a safer one under DANE */ | |
2206 | request_ocsp = TRUE; | |
2207 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
2208 | " {= {4}{$tls_out_tlsa_usage}} } " | |
2209 | " {*}{}}"; | |
2210 | } | |
2211 | # endif | |
2212 | ||
5130845b JH |
2213 | if ((require_ocsp = |
2214 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK)) | |
fca41d5a JH |
2215 | request_ocsp = TRUE; |
2216 | else | |
fca41d5a | 2217 | # ifdef EXPERIMENTAL_DANE |
4f59c424 | 2218 | if (!request_ocsp) |
fca41d5a | 2219 | # endif |
5130845b JH |
2220 | request_ocsp = |
2221 | verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
043b1248 | 2222 | } |
f5d78688 | 2223 | #endif |
059ec3d9 | 2224 | |
65867078 JH |
2225 | rc = tls_init(&client_ctx, host, NULL, |
2226 | ob->tls_certificate, ob->tls_privatekey, | |
f2de3a33 | 2227 | #ifndef DISABLE_OCSP |
44662487 | 2228 | (void *)(long)request_ocsp, |
3f7eeb86 | 2229 | #endif |
cf0c6164 | 2230 | addr, &client_static_cbinfo, errstr); |
059ec3d9 PH |
2231 | if (rc != OK) return rc; |
2232 | ||
817d9f57 | 2233 | tls_out.certificate_verified = FALSE; |
a2ff477a | 2234 | client_verify_callback_called = FALSE; |
059ec3d9 | 2235 | |
65867078 | 2236 | if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", |
cf0c6164 | 2237 | &expciphers, errstr)) |
059ec3d9 PH |
2238 | return FAIL; |
2239 | ||
2240 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
2241 | are separated by underscores. So that I can use either form in my tests, and | |
2242 | also for general convenience, we turn underscores into hyphens here. */ | |
2243 | ||
cf0c6164 | 2244 | if (expciphers) |
059ec3d9 PH |
2245 | { |
2246 | uschar *s = expciphers; | |
cf0c6164 | 2247 | while (*s) { if (*s == '_') *s = '-'; s++; } |
059ec3d9 | 2248 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); |
817d9f57 | 2249 | if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers)) |
cf0c6164 | 2250 | return tls_error(US"SSL_CTX_set_cipher_list", host, NULL, errstr); |
059ec3d9 PH |
2251 | } |
2252 | ||
043b1248 | 2253 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 2254 | if (tlsa_dnsa) |
a63be306 | 2255 | { |
02af313d JH |
2256 | SSL_CTX_set_verify(client_ctx, |
2257 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, | |
2258 | verify_callback_client_dane); | |
e5cccda9 | 2259 | |
043b1248 | 2260 | if (!DANESSL_library_init()) |
cf0c6164 | 2261 | return tls_error(US"library init", host, NULL, errstr); |
043b1248 | 2262 | if (DANESSL_CTX_init(client_ctx) <= 0) |
cf0c6164 | 2263 | return tls_error(US"context init", host, NULL, errstr); |
043b1248 JH |
2264 | } |
2265 | else | |
e51c7be2 | 2266 | |
043b1248 JH |
2267 | #endif |
2268 | ||
cf0c6164 JH |
2269 | if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob, |
2270 | client_static_cbinfo, errstr)) != OK) | |
65867078 | 2271 | return rc; |
059ec3d9 | 2272 | |
65867078 | 2273 | if ((client_ssl = SSL_new(client_ctx)) == NULL) |
cf0c6164 | 2274 | return tls_error(US"SSL_new", host, NULL, errstr); |
817d9f57 JH |
2275 | SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx)); |
2276 | SSL_set_fd(client_ssl, fd); | |
2277 | SSL_set_connect_state(client_ssl); | |
059ec3d9 | 2278 | |
65867078 | 2279 | if (ob->tls_sni) |
3f0945ff | 2280 | { |
cf0c6164 | 2281 | if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni, errstr)) |
3f0945ff | 2282 | return FAIL; |
cf0c6164 | 2283 | if (!tls_out.sni) |
2c9a0e86 PP |
2284 | { |
2285 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
2286 | } | |
ec4b68e5 | 2287 | else if (!Ustrlen(tls_out.sni)) |
817d9f57 | 2288 | tls_out.sni = NULL; |
3f0945ff PP |
2289 | else |
2290 | { | |
35731706 | 2291 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 JH |
2292 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni); |
2293 | SSL_set_tlsext_host_name(client_ssl, tls_out.sni); | |
35731706 | 2294 | #else |
66802652 | 2295 | log_write(0, LOG_MAIN, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n", |
02d9264f | 2296 | tls_out.sni); |
35731706 | 2297 | #endif |
3f0945ff PP |
2298 | } |
2299 | } | |
2300 | ||
594706ea | 2301 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 2302 | if (tlsa_dnsa) |
cf0c6164 | 2303 | if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa, errstr)) != OK) |
594706ea JH |
2304 | return rc; |
2305 | #endif | |
2306 | ||
f2de3a33 | 2307 | #ifndef DISABLE_OCSP |
f5d78688 JH |
2308 | /* Request certificate status at connection-time. If the server |
2309 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
b50c8b84 | 2310 | # ifdef EXPERIMENTAL_DANE |
594706ea JH |
2311 | if (request_ocsp) |
2312 | { | |
2313 | const uschar * s; | |
41afb5cb JH |
2314 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
2315 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
2316 | ) |
2317 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
2318 | this means we avoid the OCSP request, we wasted the setup | |
2319 | cost in tls_init(). */ | |
5130845b JH |
2320 | require_ocsp = verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; |
2321 | request_ocsp = require_ocsp | |
2322 | || verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; | |
594706ea JH |
2323 | } |
2324 | } | |
b50c8b84 JH |
2325 | # endif |
2326 | ||
44662487 JH |
2327 | if (request_ocsp) |
2328 | { | |
f5d78688 | 2329 | SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 JH |
2330 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
2331 | tls_out.ocsp = OCSP_NOT_RESP; | |
2332 | } | |
f5d78688 JH |
2333 | #endif |
2334 | ||
0cbf2b82 | 2335 | #ifndef DISABLE_EVENT |
774ef2d7 | 2336 | client_static_cbinfo->event_action = tb->event_action; |
a7538db1 | 2337 | #endif |
043b1248 | 2338 | |
059ec3d9 PH |
2339 | /* There doesn't seem to be a built-in timeout on connection. */ |
2340 | ||
2341 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
2342 | sigalrm_seen = FALSE; | |
65867078 | 2343 | alarm(ob->command_timeout); |
817d9f57 | 2344 | rc = SSL_connect(client_ssl); |
059ec3d9 PH |
2345 | alarm(0); |
2346 | ||
043b1248 | 2347 | #ifdef EXPERIMENTAL_DANE |
0e66b3b6 | 2348 | if (tlsa_dnsa) |
fde080a4 | 2349 | DANESSL_cleanup(client_ssl); |
043b1248 JH |
2350 | #endif |
2351 | ||
059ec3d9 | 2352 | if (rc <= 0) |
cf0c6164 JH |
2353 | return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL, |
2354 | errstr); | |
059ec3d9 PH |
2355 | |
2356 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
2357 | ||
f69979cf | 2358 | peer_cert(client_ssl, &tls_out, peerdn, sizeof(peerdn)); |
059ec3d9 | 2359 | |
817d9f57 JH |
2360 | construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits); |
2361 | tls_out.cipher = cipherbuf; | |
059ec3d9 | 2362 | |
9d1c15ef JH |
2363 | /* Record the certificate we presented */ |
2364 | { | |
2365 | X509 * crt = SSL_get_certificate(client_ssl); | |
2366 | tls_out.ourcert = crt ? X509_dup(crt) : NULL; | |
2367 | } | |
2368 | ||
817d9f57 | 2369 | tls_out.active = fd; |
059ec3d9 PH |
2370 | return OK; |
2371 | } | |
2372 | ||
2373 | ||
2374 | ||
2375 | ||
2376 | ||
0d81dabc JH |
2377 | static BOOL |
2378 | tls_refill(unsigned lim) | |
2379 | { | |
2380 | int error; | |
2381 | int inbytes; | |
2382 | ||
2383 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, | |
2384 | ssl_xfer_buffer, ssl_xfer_buffer_size); | |
2385 | ||
2386 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
2387 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, | |
2388 | MIN(ssl_xfer_buffer_size, lim)); | |
2389 | error = SSL_get_error(server_ssl, inbytes); | |
2390 | alarm(0); | |
2391 | ||
2392 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2393 | closed down, not that the socket itself has been closed down. Revert to | |
2394 | non-SSL handling. */ | |
2395 | ||
2396 | if (error == SSL_ERROR_ZERO_RETURN) | |
2397 | { | |
2398 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2399 | ||
2400 | receive_getc = smtp_getc; | |
2401 | receive_getbuf = smtp_getbuf; | |
2402 | receive_get_cache = smtp_get_cache; | |
2403 | receive_ungetc = smtp_ungetc; | |
2404 | receive_feof = smtp_feof; | |
2405 | receive_ferror = smtp_ferror; | |
2406 | receive_smtp_buffered = smtp_buffered; | |
2407 | ||
2408 | SSL_free(server_ssl); | |
2409 | server_ssl = NULL; | |
2410 | tls_in.active = -1; | |
2411 | tls_in.bits = 0; | |
2412 | tls_in.cipher = NULL; | |
2413 | tls_in.peerdn = NULL; | |
2414 | tls_in.sni = NULL; | |
2415 | ||
2416 | return FALSE; | |
2417 | } | |
2418 | ||
2419 | /* Handle genuine errors */ | |
2420 | ||
2421 | else if (error == SSL_ERROR_SSL) | |
2422 | { | |
2423 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2424 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); | |
2425 | ssl_xfer_error = 1; | |
2426 | return FALSE; | |
2427 | } | |
2428 | ||
2429 | else if (error != SSL_ERROR_NONE) | |
2430 | { | |
2431 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2432 | ssl_xfer_error = 1; | |
2433 | return FALSE; | |
2434 | } | |
2435 | ||
2436 | #ifndef DISABLE_DKIM | |
2437 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2438 | #endif | |
2439 | ssl_xfer_buffer_hwm = inbytes; | |
2440 | ssl_xfer_buffer_lwm = 0; | |
2441 | return TRUE; | |
2442 | } | |
2443 | ||
2444 | ||
059ec3d9 PH |
2445 | /************************************************* |
2446 | * TLS version of getc * | |
2447 | *************************************************/ | |
2448 | ||
2449 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2450 | it refills the buffer via the SSL reading function. | |
2451 | ||
bd8fbe36 | 2452 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 | 2453 | Returns: the next character or EOF |
817d9f57 JH |
2454 | |
2455 | Only used by the server-side TLS. | |
059ec3d9 PH |
2456 | */ |
2457 | ||
2458 | int | |
bd8fbe36 | 2459 | tls_getc(unsigned lim) |
059ec3d9 PH |
2460 | { |
2461 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
0d81dabc JH |
2462 | if (!tls_refill(lim)) |
2463 | return ssl_xfer_error ? EOF : smtp_getc(lim); | |
059ec3d9 | 2464 | |
0d81dabc | 2465 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2466 | |
0d81dabc JH |
2467 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; |
2468 | } | |
059ec3d9 | 2469 | |
0d81dabc JH |
2470 | uschar * |
2471 | tls_getbuf(unsigned * len) | |
2472 | { | |
2473 | unsigned size; | |
2474 | uschar * buf; | |
ba084640 | 2475 | |
0d81dabc JH |
2476 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) |
2477 | if (!tls_refill(*len)) | |
059ec3d9 | 2478 | { |
0d81dabc JH |
2479 | if (!ssl_xfer_error) return smtp_getbuf(len); |
2480 | *len = 0; | |
2481 | return NULL; | |
059ec3d9 | 2482 | } |
c80c5570 | 2483 | |
0d81dabc JH |
2484 | if ((size = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm) > *len) |
2485 | size = *len; | |
2486 | buf = &ssl_xfer_buffer[ssl_xfer_buffer_lwm]; | |
2487 | ssl_xfer_buffer_lwm += size; | |
2488 | *len = size; | |
2489 | return buf; | |
059ec3d9 PH |
2490 | } |
2491 | ||
0d81dabc | 2492 | |
584e96c6 JH |
2493 | void |
2494 | tls_get_cache() | |
2495 | { | |
9960d1e5 | 2496 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2497 | int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm; |
2498 | if (n > 0) | |
2499 | dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n); | |
584e96c6 | 2500 | #endif |
9960d1e5 | 2501 | } |
584e96c6 | 2502 | |
059ec3d9 | 2503 | |
925ac8e4 JH |
2504 | BOOL |
2505 | tls_could_read(void) | |
2506 | { | |
a5ffa9b4 | 2507 | return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(server_ssl) > 0; |
925ac8e4 JH |
2508 | } |
2509 | ||
059ec3d9 PH |
2510 | |
2511 | /************************************************* | |
2512 | * Read bytes from TLS channel * | |
2513 | *************************************************/ | |
2514 | ||
2515 | /* | |
2516 | Arguments: | |
2517 | buff buffer of data | |
2518 | len size of buffer | |
2519 | ||
2520 | Returns: the number of bytes read | |
2521 | -1 after a failed read | |
817d9f57 JH |
2522 | |
2523 | Only used by the client-side TLS. | |
059ec3d9 PH |
2524 | */ |
2525 | ||
2526 | int | |
389ca47a | 2527 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2528 | { |
389ca47a | 2529 | SSL *ssl = is_server ? server_ssl : client_ssl; |
059ec3d9 PH |
2530 | int inbytes; |
2531 | int error; | |
2532 | ||
389ca47a | 2533 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2534 | buff, (unsigned int)len); |
059ec3d9 | 2535 | |
389ca47a JH |
2536 | inbytes = SSL_read(ssl, CS buff, len); |
2537 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2538 | |
2539 | if (error == SSL_ERROR_ZERO_RETURN) | |
2540 | { | |
2541 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2542 | return -1; | |
2543 | } | |
2544 | else if (error != SSL_ERROR_NONE) | |
059ec3d9 | 2545 | return -1; |
059ec3d9 PH |
2546 | |
2547 | return inbytes; | |
2548 | } | |
2549 | ||
2550 | ||
2551 | ||
2552 | ||
2553 | ||
2554 | /************************************************* | |
2555 | * Write bytes down TLS channel * | |
2556 | *************************************************/ | |
2557 | ||
2558 | /* | |
2559 | Arguments: | |
817d9f57 | 2560 | is_server channel specifier |
059ec3d9 PH |
2561 | buff buffer of data |
2562 | len number of bytes | |
925ac8e4 | 2563 | more further data expected soon |
059ec3d9 PH |
2564 | |
2565 | Returns: the number of bytes after a successful write, | |
2566 | -1 after a failed write | |
817d9f57 JH |
2567 | |
2568 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2569 | */ |
2570 | ||
2571 | int | |
925ac8e4 | 2572 | tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2573 | { |
a5ffa9b4 | 2574 | int outbytes, error, left; |
817d9f57 | 2575 | SSL *ssl = is_server ? server_ssl : client_ssl; |
a5ffa9b4 JH |
2576 | static uschar * corked = NULL; |
2577 | static int c_size = 0, c_len = 0; | |
2578 | ||
ef698bf6 | 2579 | DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__, |
b93be52e | 2580 | buff, (unsigned long)len, more ? ", more" : ""); |
a5ffa9b4 JH |
2581 | |
2582 | /* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when | |
2583 | "more" is notified. This hack is only ok if small amounts are involved AND only | |
2584 | one stream does it, in one context (i.e. no store reset). Currently it is used | |
2585 | for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. */ | |
2586 | ||
2587 | if (is_server && (more || corked)) | |
2588 | { | |
2589 | corked = string_catn(corked, &c_size, &c_len, buff, len); | |
2590 | if (more) | |
2591 | return len; | |
2592 | buff = CUS corked; | |
2593 | len = c_len; | |
2594 | corked = NULL; c_size = c_len = 0; | |
2595 | } | |
059ec3d9 | 2596 | |
a5ffa9b4 | 2597 | for (left = len; left > 0;) |
059ec3d9 | 2598 | { |
c80c5570 | 2599 | DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); |
059ec3d9 PH |
2600 | outbytes = SSL_write(ssl, CS buff, left); |
2601 | error = SSL_get_error(ssl, outbytes); | |
2602 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2603 | switch (error) | |
2604 | { | |
2605 | case SSL_ERROR_SSL: | |
96f5fe4c JH |
2606 | ERR_error_string(ERR_get_error(), ssl_errstring); |
2607 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); | |
2608 | return -1; | |
059ec3d9 PH |
2609 | |
2610 | case SSL_ERROR_NONE: | |
96f5fe4c JH |
2611 | left -= outbytes; |
2612 | buff += outbytes; | |
2613 | break; | |
059ec3d9 PH |
2614 | |
2615 | case SSL_ERROR_ZERO_RETURN: | |
96f5fe4c JH |
2616 | log_write(0, LOG_MAIN, "SSL channel closed on write"); |
2617 | return -1; | |
059ec3d9 | 2618 | |
817d9f57 | 2619 | case SSL_ERROR_SYSCALL: |
96f5fe4c JH |
2620 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", |
2621 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
2622 | strerror(errno)); | |
2623 | return -1; | |
817d9f57 | 2624 | |
059ec3d9 | 2625 | default: |
96f5fe4c JH |
2626 | log_write(0, LOG_MAIN, "SSL_write error %d", error); |
2627 | return -1; | |
059ec3d9 PH |
2628 | } |
2629 | } | |
2630 | return len; | |
2631 | } | |
2632 | ||
2633 | ||
2634 | ||
2635 | /************************************************* | |
2636 | * Close down a TLS session * | |
2637 | *************************************************/ | |
2638 | ||
2639 | /* This is also called from within a delivery subprocess forked from the | |
2640 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2641 | would tamper with the SSL session in the parent process). | |
2642 | ||
2643 | Arguments: TRUE if SSL_shutdown is to be called | |
2644 | Returns: nothing | |
817d9f57 JH |
2645 | |
2646 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2647 | */ |
2648 | ||
2649 | void | |
817d9f57 | 2650 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2651 | { |
817d9f57 | 2652 | SSL **sslp = is_server ? &server_ssl : &client_ssl; |
389ca47a | 2653 | int *fdp = is_server ? &tls_in.active : &tls_out.active; |
817d9f57 JH |
2654 | |
2655 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
2656 | |
2657 | if (shutdown) | |
2658 | { | |
ec8b777a | 2659 | DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n"); |
817d9f57 | 2660 | SSL_shutdown(*sslp); |
059ec3d9 PH |
2661 | } |
2662 | ||
817d9f57 JH |
2663 | SSL_free(*sslp); |
2664 | *sslp = NULL; | |
059ec3d9 | 2665 | |
817d9f57 | 2666 | *fdp = -1; |
059ec3d9 PH |
2667 | } |
2668 | ||
36f12725 NM |
2669 | |
2670 | ||
2671 | ||
3375e053 PP |
2672 | /************************************************* |
2673 | * Let tls_require_ciphers be checked at startup * | |
2674 | *************************************************/ | |
2675 | ||
2676 | /* The tls_require_ciphers option, if set, must be something which the | |
2677 | library can parse. | |
2678 | ||
2679 | Returns: NULL on success, or error message | |
2680 | */ | |
2681 | ||
2682 | uschar * | |
2683 | tls_validate_require_cipher(void) | |
2684 | { | |
2685 | SSL_CTX *ctx; | |
2686 | uschar *s, *expciphers, *err; | |
2687 | ||
2688 | /* this duplicates from tls_init(), we need a better "init just global | |
2689 | state, for no specific purpose" singleton function of our own */ | |
2690 | ||
2691 | SSL_load_error_strings(); | |
2692 | OpenSSL_add_ssl_algorithms(); | |
2693 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
2694 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
2695 | list of available digests. */ | |
2696 | EVP_add_digest(EVP_sha256()); | |
2697 | #endif | |
2698 | ||
2699 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2700 | return NULL; | |
2701 | ||
cf0c6164 JH |
2702 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
2703 | &err)) | |
3375e053 PP |
2704 | return US"failed to expand tls_require_ciphers"; |
2705 | ||
2706 | if (!(expciphers && *expciphers)) | |
2707 | return NULL; | |
2708 | ||
2709 | /* normalisation ripped from above */ | |
2710 | s = expciphers; | |
2711 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
2712 | ||
2713 | err = NULL; | |
2714 | ||
2715 | ctx = SSL_CTX_new(SSLv23_server_method()); | |
2716 | if (!ctx) | |
2717 | { | |
2718 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
2719 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); | |
2720 | } | |
2721 | ||
2722 | DEBUG(D_tls) | |
2723 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2724 | ||
2725 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
2726 | { | |
2727 | ERR_error_string(ERR_get_error(), ssl_errstring); | |
cf0c6164 JH |
2728 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s", |
2729 | expciphers, ssl_errstring); | |
3375e053 PP |
2730 | } |
2731 | ||
2732 | SSL_CTX_free(ctx); | |
2733 | ||
2734 | return err; | |
2735 | } | |
2736 | ||
2737 | ||
2738 | ||
2739 | ||
36f12725 NM |
2740 | /************************************************* |
2741 | * Report the library versions. * | |
2742 | *************************************************/ | |
2743 | ||
2744 | /* There have historically been some issues with binary compatibility in | |
2745 | OpenSSL libraries; if Exim (like many other applications) is built against | |
2746 | one version of OpenSSL but the run-time linker picks up another version, | |
2747 | it can result in serious failures, including crashing with a SIGSEGV. So | |
2748 | report the version found by the compiler and the run-time version. | |
2749 | ||
f64a1e23 PP |
2750 | Note: some OS vendors backport security fixes without changing the version |
2751 | number/string, and the version date remains unchanged. The _build_ date | |
2752 | will change, so we can more usefully assist with version diagnosis by also | |
2753 | reporting the build date. | |
2754 | ||
36f12725 NM |
2755 | Arguments: a FILE* to print the results to |
2756 | Returns: nothing | |
2757 | */ | |
2758 | ||
2759 | void | |
2760 | tls_version_report(FILE *f) | |
2761 | { | |
754a0503 | 2762 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
2763 | " Runtime: %s\n" |
2764 | " : %s\n", | |
754a0503 | 2765 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
2766 | SSLeay_version(SSLEAY_VERSION), |
2767 | SSLeay_version(SSLEAY_BUILT_ON)); | |
2768 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
2769 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
2770 | } |
2771 | ||
9e3331ea TK |
2772 | |
2773 | ||
2774 | ||
2775 | /************************************************* | |
17c76198 | 2776 | * Random number generation * |
9e3331ea TK |
2777 | *************************************************/ |
2778 | ||
2779 | /* Pseudo-random number generation. The result is not expected to be | |
2780 | cryptographically strong but not so weak that someone will shoot themselves | |
2781 | in the foot using it as a nonce in input in some email header scheme or | |
2782 | whatever weirdness they'll twist this into. The result should handle fork() | |
2783 | and avoid repeating sequences. OpenSSL handles that for us. | |
2784 | ||
2785 | Arguments: | |
2786 | max range maximum | |
2787 | Returns a random number in range [0, max-1] | |
2788 | */ | |
2789 | ||
2790 | int | |
17c76198 | 2791 | vaguely_random_number(int max) |
9e3331ea TK |
2792 | { |
2793 | unsigned int r; | |
2794 | int i, needed_len; | |
de6135a0 PP |
2795 | static pid_t pidlast = 0; |
2796 | pid_t pidnow; | |
9e3331ea TK |
2797 | uschar *p; |
2798 | uschar smallbuf[sizeof(r)]; | |
2799 | ||
2800 | if (max <= 1) | |
2801 | return 0; | |
2802 | ||
de6135a0 PP |
2803 | pidnow = getpid(); |
2804 | if (pidnow != pidlast) | |
2805 | { | |
2806 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
2807 | is unique for each thread", this doesn't apparently apply across processes, | |
2808 | so our own warning from vaguely_random_number_fallback() applies here too. | |
2809 | Fix per PostgreSQL. */ | |
2810 | if (pidlast != 0) | |
2811 | RAND_cleanup(); | |
2812 | pidlast = pidnow; | |
2813 | } | |
2814 | ||
9e3331ea TK |
2815 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
2816 | if (!RAND_status()) | |
2817 | { | |
2818 | randstuff r; | |
2819 | gettimeofday(&r.tv, NULL); | |
2820 | r.p = getpid(); | |
2821 | ||
5903c6ff | 2822 | RAND_seed(US (&r), sizeof(r)); |
9e3331ea TK |
2823 | } |
2824 | /* We're after pseudo-random, not random; if we still don't have enough data | |
2825 | in the internal PRNG then our options are limited. We could sleep and hope | |
2826 | for entropy to come along (prayer technique) but if the system is so depleted | |
2827 | in the first place then something is likely to just keep taking it. Instead, | |
2828 | we'll just take whatever little bit of pseudo-random we can still manage to | |
2829 | get. */ | |
2830 | ||
2831 | needed_len = sizeof(r); | |
2832 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2833 | asked for a number less than 10. */ | |
2834 | for (r = max, i = 0; r; ++i) | |
2835 | r >>= 1; | |
2836 | i = (i + 7) / 8; | |
2837 | if (i < needed_len) | |
2838 | needed_len = i; | |
2839 | ||
c8dfb21d | 2840 | #ifdef EXIM_HAVE_RAND_PSEUDO |
9e3331ea | 2841 | /* We do not care if crypto-strong */ |
17c76198 | 2842 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
c8dfb21d JH |
2843 | #else |
2844 | i = RAND_bytes(smallbuf, needed_len); | |
2845 | #endif | |
2846 | ||
17c76198 PP |
2847 | if (i < 0) |
2848 | { | |
2849 | DEBUG(D_all) | |
2850 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
2851 | return vaguely_random_number_fallback(max); | |
2852 | } | |
2853 | ||
9e3331ea TK |
2854 | r = 0; |
2855 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2856 | { | |
2857 | r *= 256; | |
2858 | r += *p; | |
2859 | } | |
2860 | ||
2861 | /* We don't particularly care about weighted results; if someone wants | |
2862 | smooth distribution and cares enough then they should submit a patch then. */ | |
2863 | return r % max; | |
2864 | } | |
2865 | ||
77bb000f PP |
2866 | |
2867 | ||
2868 | ||
2869 | /************************************************* | |
2870 | * OpenSSL option parse * | |
2871 | *************************************************/ | |
2872 | ||
2873 | /* Parse one option for tls_openssl_options_parse below | |
2874 | ||
2875 | Arguments: | |
2876 | name one option name | |
2877 | value place to store a value for it | |
2878 | Returns success or failure in parsing | |
2879 | */ | |
2880 | ||
2881 | struct exim_openssl_option { | |
2882 | uschar *name; | |
2883 | long value; | |
2884 | }; | |
2885 | /* We could use a macro to expand, but we need the ifdef and not all the | |
2886 | options document which version they were introduced in. Policylet: include | |
2887 | all options unless explicitly for DTLS, let the administrator choose which | |
2888 | to apply. | |
2889 | ||
2890 | This list is current as of: | |
e2fbf4a2 PP |
2891 | ==> 1.0.1b <== |
2892 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
2893 | */ | |
77bb000f PP |
2894 | static struct exim_openssl_option exim_openssl_options[] = { |
2895 | /* KEEP SORTED ALPHABETICALLY! */ | |
2896 | #ifdef SSL_OP_ALL | |
73a46702 | 2897 | { US"all", SSL_OP_ALL }, |
77bb000f PP |
2898 | #endif |
2899 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
73a46702 | 2900 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, |
77bb000f PP |
2901 | #endif |
2902 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
73a46702 | 2903 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, |
77bb000f PP |
2904 | #endif |
2905 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
73a46702 | 2906 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, |
77bb000f PP |
2907 | #endif |
2908 | #ifdef SSL_OP_EPHEMERAL_RSA | |
73a46702 | 2909 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, |
77bb000f PP |
2910 | #endif |
2911 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
73a46702 | 2912 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, |
77bb000f PP |
2913 | #endif |
2914 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
73a46702 | 2915 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, |
77bb000f PP |
2916 | #endif |
2917 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
73a46702 | 2918 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, |
77bb000f PP |
2919 | #endif |
2920 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
73a46702 | 2921 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, |
77bb000f PP |
2922 | #endif |
2923 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
73a46702 | 2924 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, |
77bb000f PP |
2925 | #endif |
2926 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
73a46702 | 2927 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, |
77bb000f | 2928 | #endif |
c80c5570 PP |
2929 | #ifdef SSL_OP_NO_COMPRESSION |
2930 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
2931 | #endif | |
77bb000f | 2932 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
73a46702 | 2933 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, |
77bb000f | 2934 | #endif |
c0c7b2da PP |
2935 | #ifdef SSL_OP_NO_SSLv2 |
2936 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
2937 | #endif | |
2938 | #ifdef SSL_OP_NO_SSLv3 | |
2939 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
2940 | #endif | |
2941 | #ifdef SSL_OP_NO_TICKET | |
2942 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
2943 | #endif | |
2944 | #ifdef SSL_OP_NO_TLSv1 | |
2945 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
2946 | #endif | |
c80c5570 PP |
2947 | #ifdef SSL_OP_NO_TLSv1_1 |
2948 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
2949 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
2950 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
2951 | #else | |
2952 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
2953 | #endif | |
2954 | #endif | |
2955 | #ifdef SSL_OP_NO_TLSv1_2 | |
2956 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
2957 | #endif | |
e2fbf4a2 PP |
2958 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG |
2959 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
2960 | #endif | |
77bb000f | 2961 | #ifdef SSL_OP_SINGLE_DH_USE |
73a46702 | 2962 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, |
77bb000f PP |
2963 | #endif |
2964 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
73a46702 | 2965 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, |
77bb000f PP |
2966 | #endif |
2967 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
73a46702 | 2968 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, |
77bb000f PP |
2969 | #endif |
2970 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
73a46702 | 2971 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, |
77bb000f PP |
2972 | #endif |
2973 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
73a46702 | 2974 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, |
77bb000f PP |
2975 | #endif |
2976 | #ifdef SSL_OP_TLS_D5_BUG | |
73a46702 | 2977 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, |
77bb000f PP |
2978 | #endif |
2979 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
73a46702 | 2980 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, |
77bb000f PP |
2981 | #endif |
2982 | }; | |
2983 | static int exim_openssl_options_size = | |
2984 | sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); | |
2985 | ||
c80c5570 | 2986 | |
77bb000f PP |
2987 | static BOOL |
2988 | tls_openssl_one_option_parse(uschar *name, long *value) | |
2989 | { | |
2990 | int first = 0; | |
2991 | int last = exim_openssl_options_size; | |
2992 | while (last > first) | |
2993 | { | |
2994 | int middle = (first + last)/2; | |
2995 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
2996 | if (c == 0) | |
2997 | { | |
2998 | *value = exim_openssl_options[middle].value; | |
2999 | return TRUE; | |
3000 | } | |
3001 | else if (c > 0) | |
3002 | first = middle + 1; | |
3003 | else | |
3004 | last = middle; | |
3005 | } | |
3006 | return FALSE; | |
3007 | } | |
3008 | ||
3009 | ||
3010 | ||
3011 | ||
3012 | /************************************************* | |
3013 | * OpenSSL option parsing logic * | |
3014 | *************************************************/ | |
3015 | ||
3016 | /* OpenSSL has a number of compatibility options which an administrator might | |
3017 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
3018 | we look like log_selector. | |
3019 | ||
3020 | Arguments: | |
3021 | option_spec the administrator-supplied string of options | |
3022 | results ptr to long storage for the options bitmap | |
3023 | Returns success or failure | |
3024 | */ | |
3025 | ||
3026 | BOOL | |
3027 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
3028 | { | |
3029 | long result, item; | |
3030 | uschar *s, *end; | |
3031 | uschar keep_c; | |
3032 | BOOL adding, item_parsed; | |
3033 | ||
7006ee24 | 3034 | result = SSL_OP_NO_TICKET; |
b1770b6e | 3035 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 3036 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
3037 | #ifdef SSL_OP_NO_SSLv2 |
3038 | result |= SSL_OP_NO_SSLv2; | |
3039 | #endif | |
a57b6200 JH |
3040 | #ifdef SSL_OP_SINGLE_DH_USE |
3041 | result |= SSL_OP_SINGLE_DH_USE; | |
3042 | #endif | |
77bb000f | 3043 | |
7006ee24 | 3044 | if (!option_spec) |
77bb000f PP |
3045 | { |
3046 | *results = result; | |
3047 | return TRUE; | |
3048 | } | |
3049 | ||
3050 | for (s=option_spec; *s != '\0'; /**/) | |
3051 | { | |
3052 | while (isspace(*s)) ++s; | |
3053 | if (*s == '\0') | |
3054 | break; | |
3055 | if (*s != '+' && *s != '-') | |
3056 | { | |
3057 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 3058 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
3059 | return FALSE; |
3060 | } | |
3061 | adding = *s++ == '+'; | |
3062 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
3063 | keep_c = *end; | |
3064 | *end = '\0'; | |
3065 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
96f5fe4c | 3066 | *end = keep_c; |
77bb000f PP |
3067 | if (!item_parsed) |
3068 | { | |
0e944a0d | 3069 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
3070 | return FALSE; |
3071 | } | |
3072 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
3073 | adding ? "adding" : "removing", result, item, s); | |
3074 | if (adding) | |
3075 | result |= item; | |
3076 | else | |
3077 | result &= ~item; | |
77bb000f PP |
3078 | s = end; |
3079 | } | |
3080 | ||
3081 | *results = result; | |
3082 | return TRUE; | |
3083 | } | |
3084 | ||
9d1c15ef JH |
3085 | /* vi: aw ai sw=2 |
3086 | */ | |
059ec3d9 | 3087 | /* End of tls-openssl.c */ |