Commit | Line | Data |
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059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
f9ba5e22 | 5 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
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 |
c0635b6d | 31 | #ifdef SUPPORT_DANE |
05e796ad | 32 | # include "danessl.h" |
85098ee7 JH |
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) | |
8442641e | 54 | # define EXIM_HAVE_SHA256 |
c8dfb21d | 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 |
7a8b9519 | 73 | # define EXIM_HAVE_OPENSSL_TLS_METHOD |
7434882d JH |
74 | # else |
75 | # define EXIM_NEED_OPENSSL_INIT | |
34e3241d PP |
76 | # endif |
77 | # if OPENSSL_VERSION_NUMBER >= 0x010000000L \ | |
2dfb468b | 78 | && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L |
34e3241d PP |
79 | # define EXIM_HAVE_OPENSSL_CHECKHOST |
80 | # endif | |
11aa88b0 | 81 | #endif |
10ca4f1c | 82 | |
11aa88b0 RA |
83 | #if !defined(LIBRESSL_VERSION_NUMBER) \ |
84 | || LIBRESSL_VERSION_NUMBER >= 0x20010000L | |
10ca4f1c JH |
85 | # if !defined(OPENSSL_NO_ECDH) |
86 | # if OPENSSL_VERSION_NUMBER >= 0x0090800fL | |
8442641e | 87 | # define EXIM_HAVE_ECDH |
10ca4f1c JH |
88 | # endif |
89 | # if OPENSSL_VERSION_NUMBER >= 0x10002000L | |
10ca4f1c JH |
90 | # define EXIM_HAVE_OPENSSL_EC_NIST2NID |
91 | # endif | |
92 | # endif | |
2dfb468b | 93 | #endif |
3bcbbbe2 | 94 | |
67791ce4 JH |
95 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
96 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
97 | # define DISABLE_OCSP | |
98 | #endif | |
99 | ||
a6510420 JH |
100 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
101 | # include <openssl/x509v3.h> | |
102 | #endif | |
103 | ||
8442641e JH |
104 | /************************************************* |
105 | * OpenSSL option parse * | |
106 | *************************************************/ | |
107 | ||
108 | typedef struct exim_openssl_option { | |
109 | uschar *name; | |
110 | long value; | |
111 | } exim_openssl_option; | |
112 | /* We could use a macro to expand, but we need the ifdef and not all the | |
113 | options document which version they were introduced in. Policylet: include | |
114 | all options unless explicitly for DTLS, let the administrator choose which | |
115 | to apply. | |
116 | ||
117 | This list is current as of: | |
118 | ==> 1.0.1b <== | |
119 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
120 | Plus SSL_OP_NO_TLSv1_3 for 1.1.2-dev | |
121 | */ | |
122 | static exim_openssl_option exim_openssl_options[] = { | |
123 | /* KEEP SORTED ALPHABETICALLY! */ | |
124 | #ifdef SSL_OP_ALL | |
125 | { US"all", SSL_OP_ALL }, | |
126 | #endif | |
127 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
128 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, | |
129 | #endif | |
130 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
131 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, | |
132 | #endif | |
133 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
134 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, | |
135 | #endif | |
136 | #ifdef SSL_OP_EPHEMERAL_RSA | |
137 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, | |
138 | #endif | |
139 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
140 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, | |
141 | #endif | |
142 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
143 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, | |
144 | #endif | |
145 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
146 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, | |
147 | #endif | |
148 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
149 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, | |
150 | #endif | |
151 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
152 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, | |
153 | #endif | |
154 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
155 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, | |
156 | #endif | |
157 | #ifdef SSL_OP_NO_COMPRESSION | |
158 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
159 | #endif | |
160 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION | |
161 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, | |
162 | #endif | |
163 | #ifdef SSL_OP_NO_SSLv2 | |
164 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
165 | #endif | |
166 | #ifdef SSL_OP_NO_SSLv3 | |
167 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
168 | #endif | |
169 | #ifdef SSL_OP_NO_TICKET | |
170 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
171 | #endif | |
172 | #ifdef SSL_OP_NO_TLSv1 | |
173 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
174 | #endif | |
175 | #ifdef SSL_OP_NO_TLSv1_1 | |
176 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
177 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
178 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
179 | #else | |
180 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
181 | #endif | |
182 | #endif | |
183 | #ifdef SSL_OP_NO_TLSv1_2 | |
184 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
185 | #endif | |
186 | #ifdef SSL_OP_NO_TLSv1_3 | |
187 | { US"no_tlsv1_3", SSL_OP_NO_TLSv1_3 }, | |
188 | #endif | |
189 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG | |
190 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
191 | #endif | |
192 | #ifdef SSL_OP_SINGLE_DH_USE | |
193 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, | |
194 | #endif | |
195 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
196 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, | |
197 | #endif | |
198 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
199 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, | |
200 | #endif | |
201 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
202 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, | |
203 | #endif | |
204 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
205 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, | |
206 | #endif | |
207 | #ifdef SSL_OP_TLS_D5_BUG | |
208 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, | |
209 | #endif | |
210 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
211 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, | |
212 | #endif | |
213 | }; | |
214 | ||
215 | #ifndef MACRO_PREDEF | |
216 | static int exim_openssl_options_size = nelem(exim_openssl_options); | |
217 | #endif | |
218 | ||
219 | #ifdef MACRO_PREDEF | |
220 | void | |
221 | options_tls(void) | |
222 | { | |
223 | struct exim_openssl_option * o; | |
224 | uschar buf[64]; | |
225 | ||
226 | for (o = exim_openssl_options; | |
227 | o < exim_openssl_options + nelem(exim_openssl_options); o++) | |
228 | { | |
229 | /* Trailing X is workaround for problem with _OPT_OPENSSL_NO_TLSV1 | |
230 | being a ".ifdef _OPT_OPENSSL_NO_TLSV1_3" match */ | |
231 | ||
232 | spf(buf, sizeof(buf), US"_OPT_OPENSSL_%T_X", o->name); | |
233 | builtin_macro_create(buf); | |
234 | } | |
235 | } | |
236 | #else | |
237 | ||
238 | /******************************************************************************/ | |
239 | ||
059ec3d9 PH |
240 | /* Structure for collecting random data for seeding. */ |
241 | ||
242 | typedef struct randstuff { | |
9e3331ea TK |
243 | struct timeval tv; |
244 | pid_t p; | |
059ec3d9 PH |
245 | } randstuff; |
246 | ||
247 | /* Local static variables */ | |
248 | ||
a2ff477a JH |
249 | static BOOL client_verify_callback_called = FALSE; |
250 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
251 | static const uschar *sid_ctx = US"exim"; |
252 | ||
d4f09789 PP |
253 | /* We have three different contexts to care about. |
254 | ||
255 | Simple case: client, `client_ctx` | |
256 | As a client, we can be doing a callout or cut-through delivery while receiving | |
257 | a message. So we have a client context, which should have options initialised | |
74f1a423 JH |
258 | from the SMTP Transport. We may also concurrently want to make TLS connections |
259 | to utility daemons, so client-contexts are allocated and passed around in call | |
260 | args rather than using a gobal. | |
d4f09789 PP |
261 | |
262 | Server: | |
263 | There are two cases: with and without ServerNameIndication from the client. | |
264 | Given TLS SNI, we can be using different keys, certs and various other | |
265 | configuration settings, because they're re-expanded with $tls_sni set. This | |
266 | allows vhosting with TLS. This SNI is sent in the handshake. | |
267 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
268 | So as a server, we start out using `server_ctx`. | |
269 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
270 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
271 | configuration. | |
272 | */ | |
273 | ||
74f1a423 JH |
274 | typedef struct { |
275 | SSL_CTX * ctx; | |
276 | SSL * ssl; | |
277 | } exim_openssl_client_tls_ctx; | |
278 | ||
817d9f57 | 279 | static SSL_CTX *server_ctx = NULL; |
817d9f57 | 280 | static SSL *server_ssl = NULL; |
389ca47a | 281 | |
35731706 | 282 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 283 | static SSL_CTX *server_sni = NULL; |
35731706 | 284 | #endif |
059ec3d9 PH |
285 | |
286 | static char ssl_errstring[256]; | |
287 | ||
288 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
289 | static BOOL client_verify_optional = FALSE; |
290 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 291 | |
f5d78688 | 292 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
293 | |
294 | ||
7be682ca PP |
295 | typedef struct tls_ext_ctx_cb { |
296 | uschar *certificate; | |
297 | uschar *privatekey; | |
f5d78688 | 298 | BOOL is_server; |
a6510420 | 299 | #ifndef DISABLE_OCSP |
c3033f13 | 300 | STACK_OF(X509) *verify_stack; /* chain for verifying the proof */ |
f5d78688 JH |
301 | union { |
302 | struct { | |
303 | uschar *file; | |
304 | uschar *file_expanded; | |
305 | OCSP_RESPONSE *response; | |
306 | } server; | |
307 | struct { | |
44662487 JH |
308 | X509_STORE *verify_store; /* non-null if status requested */ |
309 | BOOL verify_required; | |
f5d78688 JH |
310 | } client; |
311 | } u_ocsp; | |
3f7eeb86 | 312 | #endif |
7be682ca PP |
313 | uschar *dhparam; |
314 | /* these are cached from first expand */ | |
315 | uschar *server_cipher_list; | |
316 | /* only passed down to tls_error: */ | |
317 | host_item *host; | |
55414b25 | 318 | const uschar * verify_cert_hostnames; |
0cbf2b82 | 319 | #ifndef DISABLE_EVENT |
a7538db1 JH |
320 | uschar * event_action; |
321 | #endif | |
7be682ca PP |
322 | } tls_ext_ctx_cb; |
323 | ||
324 | /* should figure out a cleanup of API to handle state preserved per | |
325 | implementation, for various reasons, which can be void * in the APIs. | |
326 | For now, we hack around it. */ | |
817d9f57 JH |
327 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
328 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
329 | |
330 | static int | |
983207c1 | 331 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 332 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr ); |
059ec3d9 | 333 | |
3f7eeb86 | 334 | /* Callbacks */ |
3bcbbbe2 | 335 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 336 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 337 | #endif |
f2de3a33 | 338 | #ifndef DISABLE_OCSP |
f5d78688 | 339 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
340 | #endif |
341 | ||
059ec3d9 PH |
342 | |
343 | /************************************************* | |
344 | * Handle TLS error * | |
345 | *************************************************/ | |
346 | ||
347 | /* Called from lots of places when errors occur before actually starting to do | |
348 | the TLS handshake, that is, while the session is still in clear. Always returns | |
349 | DEFER for a server and FAIL for a client so that most calls can use "return | |
350 | tls_error(...)" to do this processing and then give an appropriate return. A | |
351 | single function is used for both server and client, because it is called from | |
352 | some shared functions. | |
353 | ||
354 | Argument: | |
355 | prefix text to include in the logged error | |
356 | host NULL if setting up a server; | |
357 | the connected host if setting up a client | |
7199e1ee | 358 | msg error message or NULL if we should ask OpenSSL |
cf0c6164 | 359 | errstr pointer to output error message |
059ec3d9 PH |
360 | |
361 | Returns: OK/DEFER/FAIL | |
362 | */ | |
363 | ||
364 | static int | |
cf0c6164 | 365 | tls_error(uschar * prefix, const host_item * host, uschar * msg, uschar ** errstr) |
059ec3d9 | 366 | { |
c562fd30 | 367 | if (!msg) |
7199e1ee | 368 | { |
0abc5a13 | 369 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 | 370 | msg = US ssl_errstring; |
7199e1ee TF |
371 | } |
372 | ||
5a2a0989 JH |
373 | msg = string_sprintf("(%s): %s", prefix, msg); |
374 | DEBUG(D_tls) debug_printf("TLS error '%s'\n", msg); | |
375 | if (errstr) *errstr = msg; | |
cf0c6164 | 376 | return host ? FAIL : DEFER; |
059ec3d9 PH |
377 | } |
378 | ||
379 | ||
380 | ||
381 | /************************************************* | |
382 | * Callback to generate RSA key * | |
383 | *************************************************/ | |
384 | ||
385 | /* | |
386 | Arguments: | |
3ae79556 | 387 | s SSL connection (not used) |
059ec3d9 PH |
388 | export not used |
389 | keylength keylength | |
390 | ||
391 | Returns: pointer to generated key | |
392 | */ | |
393 | ||
394 | static RSA * | |
395 | rsa_callback(SSL *s, int export, int keylength) | |
396 | { | |
397 | RSA *rsa_key; | |
c8dfb21d JH |
398 | #ifdef EXIM_HAVE_RSA_GENKEY_EX |
399 | BIGNUM *bn = BN_new(); | |
400 | #endif | |
401 | ||
059ec3d9 PH |
402 | export = export; /* Shut picky compilers up */ |
403 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
c8dfb21d JH |
404 | |
405 | #ifdef EXIM_HAVE_RSA_GENKEY_EX | |
406 | if ( !BN_set_word(bn, (unsigned long)RSA_F4) | |
f2cb6292 | 407 | || !(rsa_key = RSA_new()) |
c8dfb21d JH |
408 | || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL) |
409 | ) | |
410 | #else | |
23bb6982 | 411 | if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL))) |
c8dfb21d JH |
412 | #endif |
413 | ||
059ec3d9 | 414 | { |
0abc5a13 | 415 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
059ec3d9 PH |
416 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", |
417 | ssl_errstring); | |
418 | return NULL; | |
419 | } | |
420 | return rsa_key; | |
421 | } | |
422 | ||
423 | ||
424 | ||
f5d78688 | 425 | /* Extreme debug |
f2de3a33 | 426 | #ifndef DISABLE_OCSP |
f5d78688 JH |
427 | void |
428 | x509_store_dump_cert_s_names(X509_STORE * store) | |
429 | { | |
430 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
431 | int i; | |
432 | static uschar name[256]; | |
433 | ||
434 | for(i= 0; i<sk_X509_OBJECT_num(roots); i++) | |
435 | { | |
436 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
437 | if(tmp_obj->type == X509_LU_X509) | |
438 | { | |
70e384dd JH |
439 | X509_NAME * sn = X509_get_subject_name(tmp_obj->data.x509); |
440 | if (X509_NAME_oneline(sn, CS name, sizeof(name))) | |
441 | { | |
442 | name[sizeof(name)-1] = '\0'; | |
443 | debug_printf(" %s\n", name); | |
444 | } | |
f5d78688 JH |
445 | } |
446 | } | |
447 | } | |
448 | #endif | |
449 | */ | |
450 | ||
059ec3d9 | 451 | |
0cbf2b82 | 452 | #ifndef DISABLE_EVENT |
f69979cf JH |
453 | static int |
454 | verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn, | |
455 | BOOL *calledp, const BOOL *optionalp, const uschar * what) | |
456 | { | |
457 | uschar * ev; | |
458 | uschar * yield; | |
459 | X509 * old_cert; | |
460 | ||
461 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; | |
462 | if (ev) | |
463 | { | |
aaba7d03 | 464 | DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth); |
f69979cf JH |
465 | old_cert = tlsp->peercert; |
466 | tlsp->peercert = X509_dup(cert); | |
467 | /* NB we do not bother setting peerdn */ | |
468 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) | |
469 | { | |
470 | log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: " | |
471 | "depth=%d cert=%s: %s", | |
472 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
473 | what, depth, dn, yield); | |
474 | *calledp = TRUE; | |
475 | if (!*optionalp) | |
476 | { | |
477 | if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */ | |
478 | return 1; /* reject (leaving peercert set) */ | |
479 | } | |
480 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
481 | "(host in tls_try_verify_hosts)\n"); | |
482 | } | |
483 | X509_free(tlsp->peercert); | |
484 | tlsp->peercert = old_cert; | |
485 | } | |
486 | return 0; | |
487 | } | |
488 | #endif | |
489 | ||
059ec3d9 PH |
490 | /************************************************* |
491 | * Callback for verification * | |
492 | *************************************************/ | |
493 | ||
494 | /* The SSL library does certificate verification if set up to do so. This | |
495 | callback has the current yes/no state is in "state". If verification succeeded, | |
f69979cf JH |
496 | we set the certificate-verified flag. If verification failed, what happens |
497 | depends on whether the client is required to present a verifiable certificate | |
498 | or not. | |
059ec3d9 PH |
499 | |
500 | If verification is optional, we change the state to yes, but still log the | |
501 | verification error. For some reason (it really would help to have proper | |
502 | documentation of OpenSSL), this callback function then gets called again, this | |
f69979cf JH |
503 | time with state = 1. We must take care not to set the private verified flag on |
504 | the second time through. | |
059ec3d9 PH |
505 | |
506 | Note: this function is not called if the client fails to present a certificate | |
507 | when asked. We get here only if a certificate has been received. Handling of | |
508 | optional verification for this case is done when requesting SSL to verify, by | |
509 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
510 | ||
a7538db1 JH |
511 | May be called multiple times for different issues with a certificate, even |
512 | for a given "depth" in the certificate chain. | |
513 | ||
059ec3d9 | 514 | Arguments: |
f2f2c91b JH |
515 | preverify_ok current yes/no state as 1/0 |
516 | x509ctx certificate information. | |
517 | tlsp per-direction (client vs. server) support data | |
518 | calledp has-been-called flag | |
519 | optionalp verification-is-optional flag | |
059ec3d9 | 520 | |
f2f2c91b | 521 | Returns: 0 if verification should fail, otherwise 1 |
059ec3d9 PH |
522 | */ |
523 | ||
524 | static int | |
70e384dd JH |
525 | verify_callback(int preverify_ok, X509_STORE_CTX * x509ctx, |
526 | tls_support * tlsp, BOOL * calledp, BOOL * optionalp) | |
059ec3d9 | 527 | { |
421aff85 | 528 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 529 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 530 | uschar dn[256]; |
059ec3d9 | 531 | |
70e384dd JH |
532 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
533 | { | |
534 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
535 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
536 | tlsp == &tls_out ? deliver_host_address : sender_host_address); | |
537 | return 0; | |
538 | } | |
f69979cf | 539 | dn[sizeof(dn)-1] = '\0'; |
059ec3d9 | 540 | |
f2f2c91b | 541 | if (preverify_ok == 0) |
059ec3d9 | 542 | { |
f77197ae JH |
543 | uschar * extra = verify_mode ? string_sprintf(" (during %c-verify for [%s])", |
544 | *verify_mode, sender_host_address) | |
545 | : US""; | |
546 | log_write(0, LOG_MAIN, "[%s] SSL verify error%s: depth=%d error=%s cert=%s", | |
547 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
548 | extra, depth, | |
549 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), dn); | |
a2ff477a | 550 | *calledp = TRUE; |
9d1c15ef JH |
551 | if (!*optionalp) |
552 | { | |
f69979cf JH |
553 | if (!tlsp->peercert) |
554 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
555 | return 0; /* reject */ | |
9d1c15ef | 556 | } |
059ec3d9 PH |
557 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
558 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
559 | } |
560 | ||
a7538db1 | 561 | else if (depth != 0) |
059ec3d9 | 562 | { |
f69979cf | 563 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn); |
f2de3a33 | 564 | #ifndef DISABLE_OCSP |
f5d78688 JH |
565 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
566 | { /* client, wanting stapling */ | |
567 | /* Add the server cert's signing chain as the one | |
568 | for the verification of the OCSP stapled information. */ | |
94431adb | 569 | |
f5d78688 | 570 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, |
421aff85 | 571 | cert)) |
f5d78688 | 572 | ERR_clear_error(); |
c3033f13 | 573 | sk_X509_push(client_static_cbinfo->verify_stack, cert); |
f5d78688 | 574 | } |
a7538db1 | 575 | #endif |
0cbf2b82 | 576 | #ifndef DISABLE_EVENT |
f69979cf JH |
577 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
578 | return 0; /* reject, with peercert set */ | |
f5d78688 | 579 | #endif |
059ec3d9 PH |
580 | } |
581 | else | |
582 | { | |
55414b25 | 583 | const uschar * verify_cert_hostnames; |
e51c7be2 | 584 | |
e51c7be2 JH |
585 | if ( tlsp == &tls_out |
586 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
afdb5e9c | 587 | /* client, wanting hostname check */ |
e51c7be2 | 588 | { |
f69979cf | 589 | |
740f36d4 | 590 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
f69979cf JH |
591 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
592 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
593 | # endif | |
594 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
595 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
596 | # endif | |
e51c7be2 | 597 | int sep = 0; |
55414b25 | 598 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 599 | uschar * name; |
d8e7834a JH |
600 | int rc; |
601 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
f40d5be3 | 602 | if ((rc = X509_check_host(cert, CCS name, 0, |
8d692470 | 603 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
740f36d4 JH |
604 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS, |
605 | NULL))) | |
d8e7834a JH |
606 | { |
607 | if (rc < 0) | |
608 | { | |
93a6fce2 | 609 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
f77197ae | 610 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
611 | name = NULL; |
612 | } | |
e51c7be2 | 613 | break; |
d8e7834a | 614 | } |
e51c7be2 | 615 | if (!name) |
f69979cf | 616 | #else |
e51c7be2 | 617 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) |
f69979cf | 618 | #endif |
e51c7be2 | 619 | { |
f77197ae JH |
620 | uschar * extra = verify_mode |
621 | ? string_sprintf(" (during %c-verify for [%s])", | |
622 | *verify_mode, sender_host_address) | |
623 | : US""; | |
e51c7be2 | 624 | log_write(0, LOG_MAIN, |
f77197ae JH |
625 | "[%s] SSL verify error%s: certificate name mismatch: DN=\"%s\" H=\"%s\"", |
626 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
627 | extra, dn, verify_cert_hostnames); | |
a3ef7310 JH |
628 | *calledp = TRUE; |
629 | if (!*optionalp) | |
f69979cf JH |
630 | { |
631 | if (!tlsp->peercert) | |
632 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
633 | return 0; /* reject */ | |
634 | } | |
a3ef7310 JH |
635 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
636 | "tls_try_verify_hosts)\n"); | |
e51c7be2 | 637 | } |
f69979cf | 638 | } |
e51c7be2 | 639 | |
0cbf2b82 | 640 | #ifndef DISABLE_EVENT |
f69979cf JH |
641 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
642 | return 0; /* reject, with peercert set */ | |
e51c7be2 JH |
643 | #endif |
644 | ||
93dcb1c2 | 645 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
f69979cf | 646 | *calledp ? "" : " authenticated", dn); |
93dcb1c2 JH |
647 | if (!*calledp) tlsp->certificate_verified = TRUE; |
648 | *calledp = TRUE; | |
059ec3d9 PH |
649 | } |
650 | ||
a7538db1 | 651 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
652 | } |
653 | ||
a2ff477a | 654 | static int |
f2f2c91b | 655 | verify_callback_client(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 656 | { |
f2f2c91b JH |
657 | return verify_callback(preverify_ok, x509ctx, &tls_out, |
658 | &client_verify_callback_called, &client_verify_optional); | |
a2ff477a JH |
659 | } |
660 | ||
661 | static int | |
f2f2c91b | 662 | verify_callback_server(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 663 | { |
f2f2c91b JH |
664 | return verify_callback(preverify_ok, x509ctx, &tls_in, |
665 | &server_verify_callback_called, &server_verify_optional); | |
a2ff477a JH |
666 | } |
667 | ||
059ec3d9 | 668 | |
c0635b6d | 669 | #ifdef SUPPORT_DANE |
53a7196b | 670 | |
e5cccda9 JH |
671 | /* This gets called *by* the dane library verify callback, which interposes |
672 | itself. | |
673 | */ | |
674 | static int | |
f2f2c91b | 675 | verify_callback_client_dane(int preverify_ok, X509_STORE_CTX * x509ctx) |
e5cccda9 JH |
676 | { |
677 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
f69979cf | 678 | uschar dn[256]; |
83b27293 | 679 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
5c75db2e | 680 | #ifndef DISABLE_EVENT |
f69979cf | 681 | BOOL dummy_called, optional = FALSE; |
83b27293 | 682 | #endif |
e5cccda9 | 683 | |
70e384dd JH |
684 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
685 | { | |
686 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
687 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
688 | deliver_host_address); | |
689 | return 0; | |
690 | } | |
f69979cf | 691 | dn[sizeof(dn)-1] = '\0'; |
e5cccda9 | 692 | |
f2f2c91b JH |
693 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s depth %d %s\n", |
694 | preverify_ok ? "ok":"BAD", depth, dn); | |
e5cccda9 | 695 | |
0cbf2b82 | 696 | #ifndef DISABLE_EVENT |
f69979cf JH |
697 | if (verify_event(&tls_out, cert, depth, dn, |
698 | &dummy_called, &optional, US"DANE")) | |
699 | return 0; /* reject, with peercert set */ | |
83b27293 JH |
700 | #endif |
701 | ||
f2f2c91b | 702 | if (preverify_ok == 1) |
6fbf3599 JH |
703 | { |
704 | tls_out.dane_verified = tls_out.certificate_verified = TRUE; | |
705 | #ifndef DISABLE_OCSP | |
706 | if (client_static_cbinfo->u_ocsp.client.verify_store) | |
707 | { /* client, wanting stapling */ | |
708 | /* Add the server cert's signing chain as the one | |
709 | for the verification of the OCSP stapled information. */ | |
710 | ||
711 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
712 | cert)) | |
713 | ERR_clear_error(); | |
714 | sk_X509_push(client_static_cbinfo->verify_stack, cert); | |
715 | } | |
716 | #endif | |
717 | } | |
f2f2c91b JH |
718 | else |
719 | { | |
720 | int err = X509_STORE_CTX_get_error(x509ctx); | |
721 | DEBUG(D_tls) | |
722 | debug_printf(" - err %d '%s'\n", err, X509_verify_cert_error_string(err)); | |
3c51463e | 723 | if (err == X509_V_ERR_APPLICATION_VERIFICATION) |
f2f2c91b JH |
724 | preverify_ok = 1; |
725 | } | |
726 | return preverify_ok; | |
e5cccda9 | 727 | } |
53a7196b | 728 | |
c0635b6d | 729 | #endif /*SUPPORT_DANE*/ |
e5cccda9 | 730 | |
059ec3d9 PH |
731 | |
732 | /************************************************* | |
733 | * Information callback * | |
734 | *************************************************/ | |
735 | ||
736 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
737 | are doing. We copy the string to the debugging output when TLS debugging has |
738 | been requested. | |
059ec3d9 PH |
739 | |
740 | Arguments: | |
741 | s the SSL connection | |
742 | where | |
743 | ret | |
744 | ||
745 | Returns: nothing | |
746 | */ | |
747 | ||
748 | static void | |
749 | info_callback(SSL *s, int where, int ret) | |
750 | { | |
0abc5a13 JH |
751 | DEBUG(D_tls) |
752 | { | |
753 | const uschar * str; | |
754 | ||
755 | if (where & SSL_ST_CONNECT) | |
48224640 | 756 | str = US"SSL_connect"; |
0abc5a13 | 757 | else if (where & SSL_ST_ACCEPT) |
48224640 | 758 | str = US"SSL_accept"; |
0abc5a13 | 759 | else |
48224640 | 760 | str = US"SSL info (undefined)"; |
0abc5a13 JH |
761 | |
762 | if (where & SSL_CB_LOOP) | |
763 | debug_printf("%s: %s\n", str, SSL_state_string_long(s)); | |
764 | else if (where & SSL_CB_ALERT) | |
765 | debug_printf("SSL3 alert %s:%s:%s\n", | |
48224640 | 766 | str = where & SSL_CB_READ ? US"read" : US"write", |
0abc5a13 JH |
767 | SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret)); |
768 | else if (where & SSL_CB_EXIT) | |
769 | if (ret == 0) | |
770 | debug_printf("%s: failed in %s\n", str, SSL_state_string_long(s)); | |
771 | else if (ret < 0) | |
772 | debug_printf("%s: error in %s\n", str, SSL_state_string_long(s)); | |
773 | else if (where & SSL_CB_HANDSHAKE_START) | |
774 | debug_printf("%s: hshake start: %s\n", str, SSL_state_string_long(s)); | |
775 | else if (where & SSL_CB_HANDSHAKE_DONE) | |
776 | debug_printf("%s: hshake done: %s\n", str, SSL_state_string_long(s)); | |
777 | } | |
059ec3d9 PH |
778 | } |
779 | ||
780 | ||
781 | ||
782 | /************************************************* | |
783 | * Initialize for DH * | |
784 | *************************************************/ | |
785 | ||
786 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
787 | ||
788 | Arguments: | |
038597d2 | 789 | sctx The current SSL CTX (inbound or outbound) |
a799883d | 790 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 791 | host connected host, if client; NULL if server |
cf0c6164 | 792 | errstr error string pointer |
059ec3d9 PH |
793 | |
794 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
795 | */ | |
796 | ||
797 | static BOOL | |
cf0c6164 | 798 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr) |
059ec3d9 | 799 | { |
059ec3d9 PH |
800 | BIO *bio; |
801 | DH *dh; | |
802 | uschar *dhexpanded; | |
a799883d | 803 | const char *pem; |
6600985a | 804 | int dh_bitsize; |
059ec3d9 | 805 | |
cf0c6164 | 806 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr)) |
059ec3d9 PH |
807 | return FALSE; |
808 | ||
0df4ab80 | 809 | if (!dhexpanded || !*dhexpanded) |
a799883d | 810 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 811 | else if (dhexpanded[0] == '/') |
059ec3d9 | 812 | { |
0df4ab80 | 813 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 814 | { |
7199e1ee | 815 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
cf0c6164 | 816 | host, US strerror(errno), errstr); |
a799883d | 817 | return FALSE; |
059ec3d9 | 818 | } |
a799883d PP |
819 | } |
820 | else | |
821 | { | |
822 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 823 | { |
a799883d PP |
824 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
825 | return TRUE; | |
059ec3d9 | 826 | } |
a799883d | 827 | |
0df4ab80 | 828 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
829 | { |
830 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
cf0c6164 | 831 | host, US strerror(errno), errstr); |
a799883d PP |
832 | return FALSE; |
833 | } | |
834 | bio = BIO_new_mem_buf(CS pem, -1); | |
835 | } | |
836 | ||
0df4ab80 | 837 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 838 | { |
059ec3d9 | 839 | BIO_free(bio); |
a799883d | 840 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
cf0c6164 | 841 | host, NULL, errstr); |
a799883d PP |
842 | return FALSE; |
843 | } | |
844 | ||
6600985a PP |
845 | /* note: our default limit of 2236 is not a multiple of 8; the limit comes from |
846 | * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with | |
847 | * 2236. But older OpenSSL can only report in bytes (octets), not bits. | |
848 | * If someone wants to dance at the edge, then they can raise the limit or use | |
849 | * current libraries. */ | |
850 | #ifdef EXIM_HAVE_OPENSSL_DH_BITS | |
851 | /* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022 | |
852 | * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */ | |
853 | dh_bitsize = DH_bits(dh); | |
854 | #else | |
855 | dh_bitsize = 8 * DH_size(dh); | |
856 | #endif | |
857 | ||
a799883d PP |
858 | /* Even if it is larger, we silently return success rather than cause things |
859 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
860 | * debatable choice. */ | |
6600985a | 861 | if (dh_bitsize > tls_dh_max_bits) |
a799883d PP |
862 | { |
863 | DEBUG(D_tls) | |
170f4904 | 864 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n", |
6600985a | 865 | dh_bitsize, tls_dh_max_bits); |
a799883d PP |
866 | } |
867 | else | |
868 | { | |
869 | SSL_CTX_set_tmp_dh(sctx, dh); | |
870 | DEBUG(D_tls) | |
871 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
6600985a | 872 | dhexpanded ? dhexpanded : US"default", dh_bitsize); |
059ec3d9 PH |
873 | } |
874 | ||
a799883d PP |
875 | DH_free(dh); |
876 | BIO_free(bio); | |
877 | ||
878 | return TRUE; | |
059ec3d9 PH |
879 | } |
880 | ||
881 | ||
882 | ||
883 | ||
038597d2 PP |
884 | /************************************************* |
885 | * Initialize for ECDH * | |
886 | *************************************************/ | |
887 | ||
888 | /* Load parameters for ECDH encryption. | |
889 | ||
890 | For now, we stick to NIST P-256 because: it's simple and easy to configure; | |
891 | it avoids any patent issues that might bite redistributors; despite events in | |
892 | the news and concerns over curve choices, we're not cryptographers, we're not | |
893 | pretending to be, and this is "good enough" to be better than no support, | |
894 | protecting against most adversaries. Given another year or two, there might | |
895 | be sufficient clarity about a "right" way forward to let us make an informed | |
896 | decision, instead of a knee-jerk reaction. | |
897 | ||
898 | Longer-term, we should look at supporting both various named curves and | |
899 | external files generated with "openssl ecparam", much as we do for init_dh(). | |
900 | We should also support "none" as a value, to explicitly avoid initialisation. | |
901 | ||
902 | Patches welcome. | |
903 | ||
904 | Arguments: | |
905 | sctx The current SSL CTX (inbound or outbound) | |
906 | host connected host, if client; NULL if server | |
cf0c6164 | 907 | errstr error string pointer |
038597d2 PP |
908 | |
909 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
910 | */ | |
911 | ||
912 | static BOOL | |
cf0c6164 | 913 | init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr) |
038597d2 | 914 | { |
63f0dbe0 JH |
915 | #ifdef OPENSSL_NO_ECDH |
916 | return TRUE; | |
917 | #else | |
918 | ||
10ca4f1c JH |
919 | EC_KEY * ecdh; |
920 | uschar * exp_curve; | |
921 | int nid; | |
922 | BOOL rv; | |
923 | ||
038597d2 PP |
924 | if (host) /* No ECDH setup for clients, only for servers */ |
925 | return TRUE; | |
926 | ||
10ca4f1c | 927 | # ifndef EXIM_HAVE_ECDH |
038597d2 PP |
928 | DEBUG(D_tls) |
929 | debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); | |
930 | return TRUE; | |
038597d2 | 931 | # else |
10ca4f1c | 932 | |
cf0c6164 | 933 | if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr)) |
10ca4f1c JH |
934 | return FALSE; |
935 | if (!exp_curve || !*exp_curve) | |
936 | return TRUE; | |
937 | ||
8e53a4fc | 938 | /* "auto" needs to be handled carefully. |
4c04137d | 939 | * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1 |
8e53a4fc | 940 | * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto |
4c04137d | 941 | * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO) |
8e53a4fc HSHR |
942 | * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection |
943 | * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b | |
944 | */ | |
10ca4f1c | 945 | if (Ustrcmp(exp_curve, "auto") == 0) |
038597d2 | 946 | { |
8e53a4fc | 947 | #if OPENSSL_VERSION_NUMBER < 0x10002000L |
10ca4f1c | 948 | DEBUG(D_tls) debug_printf( |
8e53a4fc | 949 | "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n"); |
78a3bbd5 | 950 | exp_curve = US"prime256v1"; |
8e53a4fc HSHR |
951 | #else |
952 | # if defined SSL_CTRL_SET_ECDH_AUTO | |
953 | DEBUG(D_tls) debug_printf( | |
954 | "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n"); | |
10ca4f1c JH |
955 | SSL_CTX_set_ecdh_auto(sctx, 1); |
956 | return TRUE; | |
8e53a4fc HSHR |
957 | # else |
958 | DEBUG(D_tls) debug_printf( | |
959 | "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n"); | |
960 | return TRUE; | |
961 | # endif | |
962 | #endif | |
10ca4f1c | 963 | } |
038597d2 | 964 | |
10ca4f1c JH |
965 | DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve); |
966 | if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef | |
967 | # ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID | |
968 | && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef | |
969 | # endif | |
970 | ) | |
971 | { | |
cf0c6164 JH |
972 | tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve), |
973 | host, NULL, errstr); | |
10ca4f1c JH |
974 | return FALSE; |
975 | } | |
038597d2 | 976 | |
10ca4f1c JH |
977 | if (!(ecdh = EC_KEY_new_by_curve_name(nid))) |
978 | { | |
cf0c6164 | 979 | tls_error(US"Unable to create ec curve", host, NULL, errstr); |
10ca4f1c | 980 | return FALSE; |
038597d2 | 981 | } |
10ca4f1c JH |
982 | |
983 | /* The "tmp" in the name here refers to setting a temporary key | |
984 | not to the stability of the interface. */ | |
985 | ||
986 | if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) | |
cf0c6164 | 987 | tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr); |
10ca4f1c JH |
988 | else |
989 | DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); | |
990 | ||
991 | EC_KEY_free(ecdh); | |
992 | return !rv; | |
993 | ||
994 | # endif /*EXIM_HAVE_ECDH*/ | |
995 | #endif /*OPENSSL_NO_ECDH*/ | |
038597d2 PP |
996 | } |
997 | ||
998 | ||
999 | ||
1000 | ||
f2de3a33 | 1001 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1002 | /************************************************* |
1003 | * Load OCSP information into state * | |
1004 | *************************************************/ | |
f5d78688 | 1005 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
1006 | caller has determined this is needed. Checks validity. Debugs a message |
1007 | if invalid. | |
1008 | ||
1009 | ASSUMES: single response, for single cert. | |
1010 | ||
1011 | Arguments: | |
1012 | sctx the SSL_CTX* to update | |
1013 | cbinfo various parts of session state | |
1014 | expanded the filename putatively holding an OCSP response | |
1015 | ||
1016 | */ | |
1017 | ||
1018 | static void | |
f5d78688 | 1019 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 | 1020 | { |
ee5b1e28 JH |
1021 | BIO * bio; |
1022 | OCSP_RESPONSE * resp; | |
1023 | OCSP_BASICRESP * basic_response; | |
1024 | OCSP_SINGLERESP * single_response; | |
1025 | ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd; | |
ee5b1e28 | 1026 | STACK_OF(X509) * sk; |
3f7eeb86 PP |
1027 | unsigned long verify_flags; |
1028 | int status, reason, i; | |
1029 | ||
f5d78688 JH |
1030 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
1031 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 1032 | { |
f5d78688 JH |
1033 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
1034 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
1035 | } |
1036 | ||
ee5b1e28 | 1037 | if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"))) |
3f7eeb86 PP |
1038 | { |
1039 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 1040 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
1041 | return; |
1042 | } | |
1043 | ||
1044 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
1045 | BIO_free(bio); | |
1046 | if (!resp) | |
1047 | { | |
1048 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
1049 | return; | |
1050 | } | |
1051 | ||
ee5b1e28 | 1052 | if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL) |
3f7eeb86 PP |
1053 | { |
1054 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
1055 | OCSP_response_status_str(status), status); | |
f5d78688 | 1056 | goto bad; |
3f7eeb86 PP |
1057 | } |
1058 | ||
ee5b1e28 | 1059 | if (!(basic_response = OCSP_response_get1_basic(resp))) |
3f7eeb86 PP |
1060 | { |
1061 | DEBUG(D_tls) | |
1062 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 1063 | goto bad; |
3f7eeb86 PP |
1064 | } |
1065 | ||
c3033f13 | 1066 | sk = cbinfo->verify_stack; |
3f7eeb86 PP |
1067 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ |
1068 | ||
1069 | /* May need to expose ability to adjust those flags? | |
1070 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
1071 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
1072 | ||
4c04137d | 1073 | /* This does a full verify on the OCSP proof before we load it for serving |
ee5b1e28 JH |
1074 | up; possibly overkill - just date-checks might be nice enough. |
1075 | ||
1076 | OCSP_basic_verify takes a "store" arg, but does not | |
1077 | use it for the chain verification, which is all we do | |
1078 | when OCSP_NOVERIFY is set. The content from the wire | |
1079 | "basic_response" and a cert-stack "sk" are all that is used. | |
1080 | ||
c3033f13 JH |
1081 | We have a stack, loaded in setup_certs() if tls_verify_certificates |
1082 | was a file (not a directory, or "system"). It is unfortunate we | |
1083 | cannot used the connection context store, as that would neatly | |
1084 | handle the "system" case too, but there seems to be no library | |
1085 | function for getting a stack from a store. | |
e3555426 | 1086 | [ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ] |
c3033f13 JH |
1087 | We do not free the stack since it could be needed a second time for |
1088 | SNI handling. | |
1089 | ||
4c04137d | 1090 | Separately we might try to replace using OCSP_basic_verify() - which seems to not |
5ec37a55 | 1091 | be a public interface into the OpenSSL library (there's no manual entry) - |
ee5b1e28 | 1092 | But what with? We also use OCSP_basic_verify in the client stapling callback. |
4c04137d | 1093 | And there we NEED it; we must verify that status... unless the |
ee5b1e28 JH |
1094 | library does it for us anyway? */ |
1095 | ||
1096 | if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0) | |
3f7eeb86 | 1097 | { |
ee5b1e28 JH |
1098 | DEBUG(D_tls) |
1099 | { | |
0abc5a13 | 1100 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3f7eeb86 | 1101 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); |
f5d78688 JH |
1102 | } |
1103 | goto bad; | |
3f7eeb86 PP |
1104 | } |
1105 | ||
1106 | /* Here's the simplifying assumption: there's only one response, for the | |
1107 | one certificate we use, and nothing for anything else in a chain. If this | |
1108 | proves false, we need to extract a cert id from our issued cert | |
1109 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
1110 | right cert in the stack and then calls OCSP_single_get0_status()). | |
1111 | ||
1112 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
ee5b1e28 JH |
1113 | |
1114 | if (!(single_response = OCSP_resp_get0(basic_response, 0))) | |
3f7eeb86 PP |
1115 | { |
1116 | DEBUG(D_tls) | |
1117 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 1118 | goto bad; |
3f7eeb86 PP |
1119 | } |
1120 | ||
1121 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 1122 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 1123 | { |
f5d78688 JH |
1124 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
1125 | OCSP_cert_status_str(status), status, | |
1126 | OCSP_crl_reason_str(reason), reason); | |
1127 | goto bad; | |
3f7eeb86 PP |
1128 | } |
1129 | ||
1130 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
1131 | { | |
1132 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 1133 | goto bad; |
3f7eeb86 PP |
1134 | } |
1135 | ||
f5d78688 | 1136 | supply_response: |
47195144 | 1137 | cbinfo->u_ocsp.server.response = resp; /*XXX stack?*/ |
f5d78688 JH |
1138 | return; |
1139 | ||
1140 | bad: | |
8768d548 | 1141 | if (f.running_in_test_harness) |
018058b2 JH |
1142 | { |
1143 | extern char ** environ; | |
1144 | uschar ** p; | |
47195144 | 1145 | if (environ) for (p = USS environ; *p; p++) |
018058b2 JH |
1146 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) |
1147 | { | |
1148 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
1149 | goto supply_response; | |
1150 | } | |
1151 | } | |
f5d78688 | 1152 | return; |
3f7eeb86 | 1153 | } |
f2de3a33 | 1154 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1155 | |
1156 | ||
1157 | ||
1158 | ||
23bb6982 JH |
1159 | /* Create and install a selfsigned certificate, for use in server mode */ |
1160 | ||
1161 | static int | |
cf0c6164 | 1162 | tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr) |
23bb6982 JH |
1163 | { |
1164 | X509 * x509 = NULL; | |
1165 | EVP_PKEY * pkey; | |
1166 | RSA * rsa; | |
1167 | X509_NAME * name; | |
1168 | uschar * where; | |
1169 | ||
1170 | where = US"allocating pkey"; | |
1171 | if (!(pkey = EVP_PKEY_new())) | |
1172 | goto err; | |
1173 | ||
1174 | where = US"allocating cert"; | |
1175 | if (!(x509 = X509_new())) | |
1176 | goto err; | |
1177 | ||
1178 | where = US"generating pkey"; | |
6aac3239 | 1179 | if (!(rsa = rsa_callback(NULL, 0, 2048))) |
23bb6982 JH |
1180 | goto err; |
1181 | ||
4c04137d | 1182 | where = US"assigning pkey"; |
23bb6982 JH |
1183 | if (!EVP_PKEY_assign_RSA(pkey, rsa)) |
1184 | goto err; | |
1185 | ||
1186 | X509_set_version(x509, 2); /* N+1 - version 3 */ | |
1613fd68 | 1187 | ASN1_INTEGER_set(X509_get_serialNumber(x509), 1); |
23bb6982 JH |
1188 | X509_gmtime_adj(X509_get_notBefore(x509), 0); |
1189 | X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60); /* 1 hour */ | |
1190 | X509_set_pubkey(x509, pkey); | |
1191 | ||
1192 | name = X509_get_subject_name(x509); | |
1193 | X509_NAME_add_entry_by_txt(name, "C", | |
4dc2379a | 1194 | MBSTRING_ASC, CUS "UK", -1, -1, 0); |
23bb6982 | 1195 | X509_NAME_add_entry_by_txt(name, "O", |
4dc2379a | 1196 | MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0); |
23bb6982 | 1197 | X509_NAME_add_entry_by_txt(name, "CN", |
4dc2379a | 1198 | MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0); |
23bb6982 JH |
1199 | X509_set_issuer_name(x509, name); |
1200 | ||
1201 | where = US"signing cert"; | |
1202 | if (!X509_sign(x509, pkey, EVP_md5())) | |
1203 | goto err; | |
1204 | ||
1205 | where = US"installing selfsign cert"; | |
1206 | if (!SSL_CTX_use_certificate(sctx, x509)) | |
1207 | goto err; | |
1208 | ||
1209 | where = US"installing selfsign key"; | |
1210 | if (!SSL_CTX_use_PrivateKey(sctx, pkey)) | |
1211 | goto err; | |
1212 | ||
1213 | return OK; | |
1214 | ||
1215 | err: | |
cf0c6164 | 1216 | (void) tls_error(where, NULL, NULL, errstr); |
23bb6982 JH |
1217 | if (x509) X509_free(x509); |
1218 | if (pkey) EVP_PKEY_free(pkey); | |
1219 | return DEFER; | |
1220 | } | |
1221 | ||
1222 | ||
1223 | ||
1224 | ||
ba86e143 JH |
1225 | static int |
1226 | tls_add_certfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1227 | uschar ** errstr) | |
1228 | { | |
1229 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", file); | |
1230 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS file)) | |
1231 | return tls_error(string_sprintf( | |
1232 | "SSL_CTX_use_certificate_chain_file file=%s", file), | |
1233 | cbinfo->host, NULL, errstr); | |
1234 | return 0; | |
1235 | } | |
1236 | ||
1237 | static int | |
1238 | tls_add_pkeyfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1239 | uschar ** errstr) | |
1240 | { | |
1241 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", file); | |
1242 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS file, SSL_FILETYPE_PEM)) | |
1243 | return tls_error(string_sprintf( | |
1244 | "SSL_CTX_use_PrivateKey_file file=%s", file), cbinfo->host, NULL, errstr); | |
1245 | return 0; | |
1246 | } | |
1247 | ||
1248 | ||
7be682ca PP |
1249 | /************************************************* |
1250 | * Expand key and cert file specs * | |
1251 | *************************************************/ | |
1252 | ||
f5d78688 | 1253 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
1254 | new context, if Server Name Indication was used and tls_sni was seen in |
1255 | the certificate string. | |
1256 | ||
1257 | Arguments: | |
1258 | sctx the SSL_CTX* to update | |
1259 | cbinfo various parts of session state | |
cf0c6164 | 1260 | errstr error string pointer |
7be682ca PP |
1261 | |
1262 | Returns: OK/DEFER/FAIL | |
1263 | */ | |
1264 | ||
1265 | static int | |
cf0c6164 JH |
1266 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, |
1267 | uschar ** errstr) | |
7be682ca PP |
1268 | { |
1269 | uschar *expanded; | |
1270 | ||
23bb6982 | 1271 | if (!cbinfo->certificate) |
7be682ca | 1272 | { |
ba86e143 | 1273 | if (!cbinfo->is_server) /* client */ |
23bb6982 | 1274 | return OK; |
afdb5e9c | 1275 | /* server */ |
cf0c6164 | 1276 | if (tls_install_selfsign(sctx, errstr) != OK) |
23bb6982 | 1277 | return DEFER; |
7be682ca | 1278 | } |
23bb6982 JH |
1279 | else |
1280 | { | |
ba86e143 JH |
1281 | int err; |
1282 | ||
23bb6982 JH |
1283 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
1284 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
1285 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
1286 | ) | |
1287 | reexpand_tls_files_for_sni = TRUE; | |
7be682ca | 1288 | |
cf0c6164 | 1289 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr)) |
23bb6982 JH |
1290 | return DEFER; |
1291 | ||
ba86e143 JH |
1292 | if (expanded) |
1293 | if (cbinfo->is_server) | |
1294 | { | |
1295 | const uschar * file_list = expanded; | |
1296 | int sep = 0; | |
1297 | uschar * file; | |
1298 | ||
1299 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1300 | if ((err = tls_add_certfile(sctx, cbinfo, file, errstr))) | |
1301 | return err; | |
1302 | } | |
1303 | else /* would there ever be a need for multiple client certs? */ | |
1304 | if ((err = tls_add_certfile(sctx, cbinfo, expanded, errstr))) | |
1305 | return err; | |
7be682ca | 1306 | |
5a2a0989 JH |
1307 | if ( cbinfo->privatekey |
1308 | && !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr)) | |
23bb6982 | 1309 | return DEFER; |
7be682ca | 1310 | |
23bb6982 JH |
1311 | /* If expansion was forced to fail, key_expanded will be NULL. If the result |
1312 | of the expansion is an empty string, ignore it also, and assume the private | |
1313 | key is in the same file as the certificate. */ | |
1314 | ||
1315 | if (expanded && *expanded) | |
ba86e143 JH |
1316 | if (cbinfo->is_server) |
1317 | { | |
1318 | const uschar * file_list = expanded; | |
1319 | int sep = 0; | |
1320 | uschar * file; | |
1321 | ||
1322 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1323 | if ((err = tls_add_pkeyfile(sctx, cbinfo, file, errstr))) | |
1324 | return err; | |
1325 | } | |
1326 | else /* would there ever be a need for multiple client certs? */ | |
1327 | if ((err = tls_add_pkeyfile(sctx, cbinfo, expanded, errstr))) | |
1328 | return err; | |
7be682ca PP |
1329 | } |
1330 | ||
f2de3a33 | 1331 | #ifndef DISABLE_OCSP |
f40d5be3 | 1332 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1333 | { |
47195144 | 1334 | /*XXX stack*/ |
cf0c6164 | 1335 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr)) |
3f7eeb86 PP |
1336 | return DEFER; |
1337 | ||
f40d5be3 | 1338 | if (expanded && *expanded) |
3f7eeb86 PP |
1339 | { |
1340 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f40d5be3 JH |
1341 | if ( cbinfo->u_ocsp.server.file_expanded |
1342 | && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 | 1343 | { |
f40d5be3 JH |
1344 | DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n"); |
1345 | } | |
1346 | else | |
f40d5be3 | 1347 | ocsp_load_response(sctx, cbinfo, expanded); |
3f7eeb86 PP |
1348 | } |
1349 | } | |
1350 | #endif | |
1351 | ||
7be682ca PP |
1352 | return OK; |
1353 | } | |
1354 | ||
1355 | ||
1356 | ||
1357 | ||
1358 | /************************************************* | |
1359 | * Callback to handle SNI * | |
1360 | *************************************************/ | |
1361 | ||
1362 | /* Called when acting as server during the TLS session setup if a Server Name | |
1363 | Indication extension was sent by the client. | |
1364 | ||
1365 | API documentation is OpenSSL s_server.c implementation. | |
1366 | ||
1367 | Arguments: | |
1368 | s SSL* of the current session | |
1369 | ad unknown (part of OpenSSL API) (unused) | |
1370 | arg Callback of "our" registered data | |
1371 | ||
1372 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
1373 | */ | |
1374 | ||
3bcbbbe2 | 1375 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
1376 | static int |
1377 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
1378 | { | |
1379 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 1380 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 1381 | int rc; |
3f0945ff | 1382 | int old_pool = store_pool; |
cf0c6164 | 1383 | uschar * dummy_errstr; |
7be682ca PP |
1384 | |
1385 | if (!servername) | |
1386 | return SSL_TLSEXT_ERR_OK; | |
1387 | ||
3f0945ff | 1388 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
1389 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
1390 | ||
1391 | /* Make the extension value available for expansion */ | |
3f0945ff | 1392 | store_pool = POOL_PERM; |
817d9f57 | 1393 | tls_in.sni = string_copy(US servername); |
3f0945ff | 1394 | store_pool = old_pool; |
7be682ca PP |
1395 | |
1396 | if (!reexpand_tls_files_for_sni) | |
1397 | return SSL_TLSEXT_ERR_OK; | |
1398 | ||
1399 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
1400 | not confident that memcpy wouldn't break some internal reference counting. | |
1401 | Especially since there's a references struct member, which would be off. */ | |
1402 | ||
7a8b9519 JH |
1403 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1404 | if (!(server_sni = SSL_CTX_new(TLS_server_method()))) | |
1405 | #else | |
0df4ab80 | 1406 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7a8b9519 | 1407 | #endif |
7be682ca | 1408 | { |
0abc5a13 | 1409 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
7be682ca | 1410 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); |
5a2a0989 | 1411 | goto bad; |
7be682ca PP |
1412 | } |
1413 | ||
1414 | /* Not sure how many of these are actually needed, since SSL object | |
1415 | already exists. Might even need this selfsame callback, for reneg? */ | |
1416 | ||
817d9f57 JH |
1417 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
1418 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
1419 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
1420 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
1421 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
1422 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
038597d2 | 1423 | |
cf0c6164 JH |
1424 | if ( !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr) |
1425 | || !init_ecdh(server_sni, NULL, &dummy_errstr) | |
038597d2 | 1426 | ) |
5a2a0989 | 1427 | goto bad; |
038597d2 | 1428 | |
ca954d7f JH |
1429 | if ( cbinfo->server_cipher_list |
1430 | && !SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list)) | |
5a2a0989 | 1431 | goto bad; |
ca954d7f | 1432 | |
f2de3a33 | 1433 | #ifndef DISABLE_OCSP |
f5d78688 | 1434 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1435 | { |
f5d78688 | 1436 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 1437 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
1438 | } |
1439 | #endif | |
7be682ca | 1440 | |
c3033f13 | 1441 | if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, |
cf0c6164 | 1442 | verify_callback_server, &dummy_errstr)) != OK) |
5a2a0989 | 1443 | goto bad; |
7be682ca | 1444 | |
3f7eeb86 PP |
1445 | /* do this after setup_certs, because this can require the certs for verifying |
1446 | OCSP information. */ | |
cf0c6164 | 1447 | if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK) |
5a2a0989 | 1448 | goto bad; |
a799883d | 1449 | |
7be682ca | 1450 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 1451 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca | 1452 | return SSL_TLSEXT_ERR_OK; |
5a2a0989 JH |
1453 | |
1454 | bad: return SSL_TLSEXT_ERR_ALERT_FATAL; | |
7be682ca | 1455 | } |
3bcbbbe2 | 1456 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
1457 | |
1458 | ||
1459 | ||
1460 | ||
f2de3a33 | 1461 | #ifndef DISABLE_OCSP |
f5d78688 | 1462 | |
3f7eeb86 PP |
1463 | /************************************************* |
1464 | * Callback to handle OCSP Stapling * | |
1465 | *************************************************/ | |
1466 | ||
1467 | /* Called when acting as server during the TLS session setup if the client | |
1468 | requests OCSP information with a Certificate Status Request. | |
1469 | ||
1470 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
1471 | project. | |
1472 | ||
1473 | */ | |
1474 | ||
1475 | static int | |
f5d78688 | 1476 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
1477 | { |
1478 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
47195144 | 1479 | uschar *response_der; /*XXX blob */ |
3f7eeb86 PP |
1480 | int response_der_len; |
1481 | ||
47195144 JH |
1482 | /*XXX stack: use SSL_get_certificate() to see which cert; from that work |
1483 | out which ocsp blob to send. Unfortunately, SSL_get_certificate is known | |
1484 | buggy in current OpenSSL; it returns the last cert loaded always rather than | |
1485 | the one actually presented. So we can't support a stack of OCSP proofs at | |
1486 | this time. */ | |
1487 | ||
af4a1bca | 1488 | DEBUG(D_tls) |
b3ef41c9 | 1489 | debug_printf("Received TLS status request (OCSP stapling); %s response\n", |
f5d78688 JH |
1490 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
1491 | ||
44662487 | 1492 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 1493 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
1494 | return SSL_TLSEXT_ERR_NOACK; |
1495 | ||
1496 | response_der = NULL; | |
47195144 | 1497 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, /*XXX stack*/ |
44662487 | 1498 | &response_der); |
3f7eeb86 PP |
1499 | if (response_der_len <= 0) |
1500 | return SSL_TLSEXT_ERR_NOACK; | |
1501 | ||
5e55c7a9 | 1502 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 1503 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
1504 | return SSL_TLSEXT_ERR_OK; |
1505 | } | |
1506 | ||
3f7eeb86 | 1507 | |
f5d78688 JH |
1508 | static void |
1509 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
1510 | { | |
1511 | BIO_printf(bp, "\t%s: ", str); | |
1512 | ASN1_GENERALIZEDTIME_print(bp, time); | |
1513 | BIO_puts(bp, "\n"); | |
1514 | } | |
1515 | ||
1516 | static int | |
1517 | tls_client_stapling_cb(SSL *s, void *arg) | |
1518 | { | |
1519 | tls_ext_ctx_cb * cbinfo = arg; | |
1520 | const unsigned char * p; | |
1521 | int len; | |
1522 | OCSP_RESPONSE * rsp; | |
1523 | OCSP_BASICRESP * bs; | |
1524 | int i; | |
1525 | ||
1526 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
1527 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
1528 | if(!p) | |
1529 | { | |
44662487 | 1530 | /* Expect this when we requested ocsp but got none */ |
6c6d6e48 | 1531 | if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher)) |
44662487 | 1532 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); |
f5d78688 JH |
1533 | else |
1534 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1535 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1536 | } |
018058b2 | 1537 | |
f5d78688 JH |
1538 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
1539 | { | |
018058b2 | 1540 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1541 | if (LOGGING(tls_cipher)) |
1eca31ca | 1542 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
1543 | else |
1544 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1545 | return 0; | |
1546 | } | |
1547 | ||
1548 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
1549 | { | |
018058b2 | 1550 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1551 | if (LOGGING(tls_cipher)) |
1eca31ca | 1552 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1553 | else |
1554 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1555 | OCSP_RESPONSE_free(rsp); | |
1556 | return 0; | |
1557 | } | |
1558 | ||
1559 | /* We'd check the nonce here if we'd put one in the request. */ | |
1560 | /* However that would defeat cacheability on the server so we don't. */ | |
1561 | ||
f5d78688 JH |
1562 | /* This section of code reworked from OpenSSL apps source; |
1563 | The OpenSSL Project retains copyright: | |
1564 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1565 | */ | |
1566 | { | |
1567 | BIO * bp = NULL; | |
f5d78688 JH |
1568 | int status, reason; |
1569 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1570 | ||
57887ecc | 1571 | DEBUG(D_tls) bp = BIO_new_fp(debug_file, BIO_NOCLOSE); |
f5d78688 JH |
1572 | |
1573 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1574 | ||
1575 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1576 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1577 | ||
c3033f13 | 1578 | if ((i = OCSP_basic_verify(bs, cbinfo->verify_stack, |
44662487 | 1579 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) |
f5d78688 | 1580 | { |
018058b2 | 1581 | tls_out.ocsp = OCSP_FAILED; |
57887ecc JH |
1582 | if (LOGGING(tls_cipher)) log_write(0, LOG_MAIN, |
1583 | "Received TLS cert status response, itself unverifiable: %s", | |
1584 | ERR_reason_error_string(ERR_peek_error())); | |
f5d78688 JH |
1585 | BIO_printf(bp, "OCSP response verify failure\n"); |
1586 | ERR_print_errors(bp); | |
57887ecc | 1587 | OCSP_RESPONSE_print(bp, rsp, 0); |
c8dfb21d | 1588 | goto failed; |
f5d78688 JH |
1589 | } |
1590 | ||
1591 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1592 | ||
c8dfb21d JH |
1593 | /*XXX So we have a good stapled OCSP status. How do we know |
1594 | it is for the cert of interest? OpenSSL 1.1.0 has a routine | |
1595 | OCSP_resp_find_status() which matches on a cert id, which presumably | |
1596 | we should use. Making an id needs OCSP_cert_id_new(), which takes | |
1597 | issuerName, issuerKey, serialNumber. Are they all in the cert? | |
1598 | ||
1599 | For now, carry on blindly accepting the resp. */ | |
1600 | ||
f5d78688 | 1601 | { |
f5d78688 JH |
1602 | OCSP_SINGLERESP * single; |
1603 | ||
c8dfb21d JH |
1604 | #ifdef EXIM_HAVE_OCSP_RESP_COUNT |
1605 | if (OCSP_resp_count(bs) != 1) | |
1606 | #else | |
1607 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
f5d78688 | 1608 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) |
c8dfb21d | 1609 | #endif |
f5d78688 | 1610 | { |
018058b2 | 1611 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1612 | log_write(0, LOG_MAIN, "OCSP stapling " |
1613 | "with multiple responses not handled"); | |
c8dfb21d | 1614 | goto failed; |
f5d78688 JH |
1615 | } |
1616 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1617 | status = OCSP_single_get0_status(single, &reason, &rev, |
1618 | &thisupd, &nextupd); | |
f5d78688 JH |
1619 | } |
1620 | ||
f5d78688 JH |
1621 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1622 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1623 | if (!OCSP_check_validity(thisupd, nextupd, |
1624 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1625 | { |
018058b2 | 1626 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1627 | DEBUG(D_tls) ERR_print_errors(bp); |
1628 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
f5d78688 | 1629 | } |
44662487 | 1630 | else |
f5d78688 | 1631 | { |
44662487 JH |
1632 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1633 | OCSP_cert_status_str(status)); | |
1634 | switch(status) | |
1635 | { | |
1636 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1637 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1638 | i = 1; |
c8dfb21d | 1639 | goto good; |
44662487 | 1640 | case V_OCSP_CERTSTATUS_REVOKED: |
018058b2 | 1641 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1642 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1643 | reason != -1 ? "; reason: " : "", | |
1644 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1645 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
44662487 JH |
1646 | break; |
1647 | default: | |
018058b2 | 1648 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1649 | log_write(0, LOG_MAIN, |
1650 | "Server certificate status unknown, in OCSP stapling"); | |
44662487 JH |
1651 | break; |
1652 | } | |
f5d78688 | 1653 | } |
c8dfb21d JH |
1654 | failed: |
1655 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1656 | good: | |
f5d78688 JH |
1657 | BIO_free(bp); |
1658 | } | |
1659 | ||
1660 | OCSP_RESPONSE_free(rsp); | |
1661 | return i; | |
1662 | } | |
f2de3a33 | 1663 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1664 | |
1665 | ||
059ec3d9 PH |
1666 | /************************************************* |
1667 | * Initialize for TLS * | |
1668 | *************************************************/ | |
1669 | ||
e51c7be2 JH |
1670 | /* Called from both server and client code, to do preliminary initialization |
1671 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1672 | |
1673 | Arguments: | |
946ecbe0 | 1674 | ctxp returned SSL context |
059ec3d9 PH |
1675 | host connected host, if client; NULL if server |
1676 | dhparam DH parameter file | |
1677 | certificate certificate file | |
1678 | privatekey private key | |
f5d78688 | 1679 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1680 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1681 | cbp place to put allocated callback context |
cf0c6164 | 1682 | errstr error string pointer |
059ec3d9 PH |
1683 | |
1684 | Returns: OK/DEFER/FAIL | |
1685 | */ | |
1686 | ||
1687 | static int | |
817d9f57 | 1688 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1689 | uschar *privatekey, |
f2de3a33 | 1690 | #ifndef DISABLE_OCSP |
47195144 | 1691 | uschar *ocsp_file, /*XXX stack, in server*/ |
3f7eeb86 | 1692 | #endif |
cf0c6164 | 1693 | address_item *addr, tls_ext_ctx_cb ** cbp, uschar ** errstr) |
059ec3d9 | 1694 | { |
7006ee24 | 1695 | SSL_CTX * ctx; |
77bb000f | 1696 | long init_options; |
7be682ca | 1697 | int rc; |
a7538db1 | 1698 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1699 | |
1700 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1701 | cbinfo->certificate = certificate; | |
1702 | cbinfo->privatekey = privatekey; | |
a6510420 | 1703 | cbinfo->is_server = host==NULL; |
f2de3a33 | 1704 | #ifndef DISABLE_OCSP |
c3033f13 | 1705 | cbinfo->verify_stack = NULL; |
a6510420 | 1706 | if (!host) |
f5d78688 JH |
1707 | { |
1708 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1709 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1710 | cbinfo->u_ocsp.server.response = NULL; | |
1711 | } | |
1712 | else | |
1713 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1714 | #endif |
7be682ca | 1715 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1716 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1717 | cbinfo->host = host; |
0cbf2b82 | 1718 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1719 | cbinfo->event_action = NULL; |
1720 | #endif | |
77bb000f | 1721 | |
7434882d | 1722 | #ifdef EXIM_NEED_OPENSSL_INIT |
059ec3d9 PH |
1723 | SSL_load_error_strings(); /* basic set up */ |
1724 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 1725 | #endif |
059ec3d9 | 1726 | |
c8dfb21d | 1727 | #ifdef EXIM_HAVE_SHA256 |
77bb000f | 1728 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1729 | list of available digests. */ |
1730 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1731 | #endif |
a0475b69 | 1732 | |
f0f5a555 PP |
1733 | /* Create a context. |
1734 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1735 | negotiation in the different methods; as far as I can tell, the only | |
1736 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1737 | when OpenSSL is built without SSLv2 support. | |
1738 | By disabling with openssl_options, we can let admins re-enable with the | |
1739 | existing knob. */ | |
059ec3d9 | 1740 | |
7a8b9519 JH |
1741 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1742 | if (!(ctx = SSL_CTX_new(host ? TLS_client_method() : TLS_server_method()))) | |
1743 | #else | |
7006ee24 | 1744 | if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method()))) |
7a8b9519 | 1745 | #endif |
7006ee24 | 1746 | return tls_error(US"SSL_CTX_new", host, NULL, errstr); |
059ec3d9 PH |
1747 | |
1748 | /* It turns out that we need to seed the random number generator this early in | |
1749 | order to get the full complement of ciphers to work. It took me roughly a day | |
1750 | of work to discover this by experiment. | |
1751 | ||
1752 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1753 | there. Otherwise, we have to make something up as best we can. Double check | |
1754 | afterwards. */ | |
1755 | ||
1756 | if (!RAND_status()) | |
1757 | { | |
1758 | randstuff r; | |
9e3331ea | 1759 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1760 | r.p = getpid(); |
1761 | ||
5903c6ff JH |
1762 | RAND_seed(US (&r), sizeof(r)); |
1763 | RAND_seed(US big_buffer, big_buffer_size); | |
1764 | if (addr != NULL) RAND_seed(US addr, sizeof(addr)); | |
059ec3d9 PH |
1765 | |
1766 | if (!RAND_status()) | |
7199e1ee | 1767 | return tls_error(US"RAND_status", host, |
cf0c6164 | 1768 | US"unable to seed random number generator", errstr); |
059ec3d9 PH |
1769 | } |
1770 | ||
1771 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1772 | level. */ | |
1773 | ||
7006ee24 | 1774 | DEBUG(D_tls) SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); |
059ec3d9 | 1775 | |
c80c5570 | 1776 | /* Automatically re-try reads/writes after renegotiation. */ |
7006ee24 | 1777 | (void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1778 | |
77bb000f PP |
1779 | /* Apply administrator-supplied work-arounds. |
1780 | Historically we applied just one requested option, | |
1781 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1782 | moved to an administrator-controlled list of options to specify and | |
1783 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1784 | |
77bb000f PP |
1785 | No OpenSSL version number checks: the options we accept depend upon the |
1786 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1787 | |
7006ee24 | 1788 | if (!tls_openssl_options_parse(openssl_options, &init_options)) |
cf0c6164 | 1789 | return tls_error(US"openssl_options parsing failed", host, NULL, errstr); |
77bb000f PP |
1790 | |
1791 | if (init_options) | |
1792 | { | |
1793 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
7006ee24 | 1794 | if (!(SSL_CTX_set_options(ctx, init_options))) |
77bb000f | 1795 | return tls_error(string_sprintf( |
cf0c6164 | 1796 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL, errstr); |
77bb000f PP |
1797 | } |
1798 | else | |
1799 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 | 1800 | |
a28050f8 JH |
1801 | /* We'd like to disable session cache unconditionally, but foolish Outlook |
1802 | Express clients then give up the first TLS connection and make a second one | |
1803 | (which works). Only when there is an IMAP service on the same machine. | |
1804 | Presumably OE is trying to use the cache for A on B. Leave it enabled for | |
1805 | now, until we work out a decent way of presenting control to the config. It | |
1806 | will never be used because we use a new context every time. */ | |
1807 | #ifdef notdef | |
7006ee24 | 1808 | (void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF); |
a28050f8 | 1809 | #endif |
7006ee24 | 1810 | |
059ec3d9 | 1811 | /* Initialize with DH parameters if supplied */ |
10ca4f1c | 1812 | /* Initialize ECDH temp key parameter selection */ |
059ec3d9 | 1813 | |
7006ee24 JH |
1814 | if ( !init_dh(ctx, dhparam, host, errstr) |
1815 | || !init_ecdh(ctx, host, errstr) | |
038597d2 PP |
1816 | ) |
1817 | return DEFER; | |
059ec3d9 | 1818 | |
3f7eeb86 | 1819 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1820 | |
7006ee24 | 1821 | if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK) |
23bb6982 | 1822 | return rc; |
c91535f3 | 1823 | |
c3033f13 JH |
1824 | /* If we need to handle SNI or OCSP, do so */ |
1825 | ||
3bcbbbe2 | 1826 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
c3033f13 JH |
1827 | # ifndef DISABLE_OCSP |
1828 | if (!(cbinfo->verify_stack = sk_X509_new_null())) | |
1829 | { | |
1830 | DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n"); | |
1831 | return FAIL; | |
1832 | } | |
1833 | # endif | |
1834 | ||
7a8b9519 | 1835 | if (!host) /* server */ |
3f0945ff | 1836 | { |
f2de3a33 | 1837 | # ifndef DISABLE_OCSP |
f5d78688 | 1838 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1839 | the option exists, not what the current expansion might be, as SNI might |
1840 | change the certificate and OCSP file in use between now and the time the | |
1841 | callback is invoked. */ | |
f5d78688 | 1842 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1843 | { |
7006ee24 JH |
1844 | SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb); |
1845 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
3f7eeb86 | 1846 | } |
f5d78688 | 1847 | # endif |
3f0945ff PP |
1848 | /* We always do this, so that $tls_sni is available even if not used in |
1849 | tls_certificate */ | |
7006ee24 JH |
1850 | SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); |
1851 | SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo); | |
3f0945ff | 1852 | } |
f2de3a33 | 1853 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1854 | else /* client */ |
1855 | if(ocsp_file) /* wanting stapling */ | |
1856 | { | |
1857 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1858 | { | |
1859 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1860 | return FAIL; | |
1861 | } | |
7006ee24 JH |
1862 | SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb); |
1863 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
f5d78688 JH |
1864 | } |
1865 | # endif | |
7be682ca | 1866 | #endif |
059ec3d9 | 1867 | |
e51c7be2 | 1868 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 1869 | |
c8dfb21d | 1870 | #ifdef EXIM_HAVE_EPHEM_RSA_KEX |
059ec3d9 | 1871 | /* Set up the RSA callback */ |
7006ee24 | 1872 | SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); |
c8dfb21d | 1873 | #endif |
059ec3d9 PH |
1874 | |
1875 | /* Finally, set the timeout, and we are done */ | |
1876 | ||
7006ee24 | 1877 | SSL_CTX_set_timeout(ctx, ssl_session_timeout); |
059ec3d9 | 1878 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1879 | |
817d9f57 | 1880 | *cbp = cbinfo; |
7006ee24 | 1881 | *ctxp = ctx; |
7be682ca | 1882 | |
059ec3d9 PH |
1883 | return OK; |
1884 | } | |
1885 | ||
1886 | ||
1887 | ||
1888 | ||
1889 | /************************************************* | |
1890 | * Get name of cipher in use * | |
1891 | *************************************************/ | |
1892 | ||
817d9f57 | 1893 | /* |
059ec3d9 | 1894 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1895 | buffer to use for answer |
1896 | size of buffer | |
1897 | pointer to number of bits for cipher | |
059ec3d9 PH |
1898 | Returns: nothing |
1899 | */ | |
1900 | ||
1901 | static void | |
817d9f57 | 1902 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1903 | { |
7a8b9519 | 1904 | /* With OpenSSL 1.0.0a, 'c' needs to be const but the documentation doesn't |
57b3a7f5 PP |
1905 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have |
1906 | the accessor functions use const in the prototype. */ | |
059ec3d9 | 1907 | |
7a8b9519 JH |
1908 | const uschar * ver = CUS SSL_get_version(ssl); |
1909 | const SSL_CIPHER * c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); | |
059ec3d9 | 1910 | |
817d9f57 | 1911 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1912 | |
817d9f57 JH |
1913 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1914 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1915 | |
1916 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1917 | } | |
1918 | ||
1919 | ||
f69979cf | 1920 | static void |
70e384dd | 1921 | peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned siz) |
f69979cf JH |
1922 | { |
1923 | /*XXX we might consider a list-of-certs variable for the cert chain. | |
1924 | SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support | |
1925 | in list-handling functions, also consider the difference between the entire | |
1926 | chain and the elements sent by the peer. */ | |
1927 | ||
70e384dd JH |
1928 | tlsp->peerdn = NULL; |
1929 | ||
f69979cf JH |
1930 | /* Will have already noted peercert on a verify fail; possibly not the leaf */ |
1931 | if (!tlsp->peercert) | |
1932 | tlsp->peercert = SSL_get_peer_certificate(ssl); | |
1933 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
1934 | if (tlsp->peercert) | |
70e384dd JH |
1935 | if (!X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, siz)) |
1936 | { DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); } | |
1937 | else | |
1938 | { | |
1939 | peerdn[siz-1] = '\0'; | |
1940 | tlsp->peerdn = peerdn; /*XXX a static buffer... */ | |
1941 | } | |
f69979cf JH |
1942 | } |
1943 | ||
1944 | ||
059ec3d9 PH |
1945 | |
1946 | ||
1947 | ||
1948 | /************************************************* | |
1949 | * Set up for verifying certificates * | |
1950 | *************************************************/ | |
1951 | ||
0e8aed8a | 1952 | #ifndef DISABLE_OCSP |
c3033f13 JH |
1953 | /* Load certs from file, return TRUE on success */ |
1954 | ||
1955 | static BOOL | |
1956 | chain_from_pem_file(const uschar * file, STACK_OF(X509) * verify_stack) | |
1957 | { | |
1958 | BIO * bp; | |
1959 | X509 * x; | |
1960 | ||
dec766a1 WB |
1961 | while (sk_X509_num(verify_stack) > 0) |
1962 | X509_free(sk_X509_pop(verify_stack)); | |
1963 | ||
c3033f13 JH |
1964 | if (!(bp = BIO_new_file(CS file, "r"))) return FALSE; |
1965 | while ((x = PEM_read_bio_X509(bp, NULL, 0, NULL))) | |
1966 | sk_X509_push(verify_stack, x); | |
1967 | BIO_free(bp); | |
1968 | return TRUE; | |
1969 | } | |
0e8aed8a | 1970 | #endif |
c3033f13 JH |
1971 | |
1972 | ||
1973 | ||
dec766a1 WB |
1974 | /* Called by both client and server startup; on the server possibly |
1975 | repeated after a Server Name Indication. | |
059ec3d9 PH |
1976 | |
1977 | Arguments: | |
7be682ca | 1978 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1979 | certs certs file or NULL |
1980 | crl CRL file or NULL | |
1981 | host NULL in a server; the remote host in a client | |
1982 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1983 | otherwise passed as FALSE | |
983207c1 | 1984 | cert_vfy_cb Callback function for certificate verification |
cf0c6164 | 1985 | errstr error string pointer |
059ec3d9 PH |
1986 | |
1987 | Returns: OK/DEFER/FAIL | |
1988 | */ | |
1989 | ||
1990 | static int | |
983207c1 | 1991 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 1992 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr) |
059ec3d9 PH |
1993 | { |
1994 | uschar *expcerts, *expcrl; | |
1995 | ||
cf0c6164 | 1996 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts, errstr)) |
059ec3d9 | 1997 | return DEFER; |
57cc2785 | 1998 | DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts); |
059ec3d9 | 1999 | |
10a831a3 | 2000 | if (expcerts && *expcerts) |
059ec3d9 | 2001 | { |
10a831a3 JH |
2002 | /* Tell the library to use its compiled-in location for the system default |
2003 | CA bundle. Then add the ones specified in the config, if any. */ | |
cb1d7830 | 2004 | |
10a831a3 | 2005 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
cf0c6164 | 2006 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr); |
10a831a3 JH |
2007 | |
2008 | if (Ustrcmp(expcerts, "system") != 0) | |
059ec3d9 | 2009 | { |
cb1d7830 JH |
2010 | struct stat statbuf; |
2011 | ||
cb1d7830 JH |
2012 | if (Ustat(expcerts, &statbuf) < 0) |
2013 | { | |
2014 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2015 | "failed to stat %s for certificates", expcerts); | |
2016 | return DEFER; | |
2017 | } | |
059ec3d9 | 2018 | else |
059ec3d9 | 2019 | { |
cb1d7830 JH |
2020 | uschar *file, *dir; |
2021 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
2022 | { file = NULL; dir = expcerts; } | |
2023 | else | |
c3033f13 JH |
2024 | { |
2025 | file = expcerts; dir = NULL; | |
2026 | #ifndef DISABLE_OCSP | |
2027 | /* In the server if we will be offering an OCSP proof, load chain from | |
2028 | file for verifying the OCSP proof at load time. */ | |
2029 | ||
2030 | if ( !host | |
2031 | && statbuf.st_size > 0 | |
2032 | && server_static_cbinfo->u_ocsp.server.file | |
2033 | && !chain_from_pem_file(file, server_static_cbinfo->verify_stack) | |
2034 | ) | |
2035 | { | |
2036 | log_write(0, LOG_MAIN|LOG_PANIC, | |
57887ecc | 2037 | "failed to load cert chain from %s", file); |
c3033f13 JH |
2038 | return DEFER; |
2039 | } | |
2040 | #endif | |
2041 | } | |
cb1d7830 JH |
2042 | |
2043 | /* If a certificate file is empty, the next function fails with an | |
2044 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
2045 | certificates are recognized, but the error message is still misleading (it | |
c3033f13 | 2046 | says no certificate was supplied). But this is better. */ |
cb1d7830 | 2047 | |
f2f2c91b JH |
2048 | if ( (!file || statbuf.st_size > 0) |
2049 | && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
cf0c6164 | 2050 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr); |
cb1d7830 JH |
2051 | |
2052 | /* Load the list of CAs for which we will accept certs, for sending | |
2053 | to the client. This is only for the one-file tls_verify_certificates | |
2054 | variant. | |
2055 | If a list isn't loaded into the server, but | |
2056 | some verify locations are set, the server end appears to make | |
4c04137d | 2057 | a wildcard request for client certs. |
10a831a3 | 2058 | Meanwhile, the client library as default behaviour *ignores* the list |
cb1d7830 JH |
2059 | we send over the wire - see man SSL_CTX_set_client_cert_cb. |
2060 | Because of this, and that the dir variant is likely only used for | |
2061 | the public-CA bundle (not for a private CA), not worth fixing. | |
2062 | */ | |
f2f2c91b | 2063 | if (file) |
cb1d7830 | 2064 | { |
2009ecca | 2065 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); |
dec766a1 WB |
2066 | |
2067 | SSL_CTX_set_client_CA_list(sctx, names); | |
f2f2c91b | 2068 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", |
cb1d7830 | 2069 | sk_X509_NAME_num(names)); |
cb1d7830 | 2070 | } |
059ec3d9 PH |
2071 | } |
2072 | } | |
2073 | ||
2074 | /* Handle a certificate revocation list. */ | |
2075 | ||
10a831a3 | 2076 | #if OPENSSL_VERSION_NUMBER > 0x00907000L |
059ec3d9 | 2077 | |
8b417f2c | 2078 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
10a831a3 | 2079 | merely reformatted it into the Exim code style.) |
8b417f2c | 2080 | |
10a831a3 JH |
2081 | "From here I changed the code to add support for multiple crl's |
2082 | in pem format in one file or to support hashed directory entries in | |
2083 | pem format instead of a file. This method now uses the library function | |
2084 | X509_STORE_load_locations to add the CRL location to the SSL context. | |
2085 | OpenSSL will then handle the verify against CA certs and CRLs by | |
2086 | itself in the verify callback." */ | |
8b417f2c | 2087 | |
cf0c6164 | 2088 | if (!expand_check(crl, US"tls_crl", &expcrl, errstr)) return DEFER; |
10a831a3 | 2089 | if (expcrl && *expcrl) |
059ec3d9 | 2090 | { |
8b417f2c PH |
2091 | struct stat statbufcrl; |
2092 | if (Ustat(expcrl, &statbufcrl) < 0) | |
2093 | { | |
2094 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2095 | "failed to stat %s for certificates revocation lists", expcrl); | |
2096 | return DEFER; | |
2097 | } | |
2098 | else | |
059ec3d9 | 2099 | { |
8b417f2c PH |
2100 | /* is it a file or directory? */ |
2101 | uschar *file, *dir; | |
7be682ca | 2102 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 2103 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 2104 | { |
8b417f2c PH |
2105 | file = NULL; |
2106 | dir = expcrl; | |
2107 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
2108 | } |
2109 | else | |
2110 | { | |
8b417f2c PH |
2111 | file = expcrl; |
2112 | dir = NULL; | |
2113 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 2114 | } |
8b417f2c | 2115 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
cf0c6164 | 2116 | return tls_error(US"X509_STORE_load_locations", host, NULL, errstr); |
8b417f2c PH |
2117 | |
2118 | /* setting the flags to check against the complete crl chain */ | |
2119 | ||
2120 | X509_STORE_set_flags(cvstore, | |
2121 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 2122 | } |
059ec3d9 PH |
2123 | } |
2124 | ||
10a831a3 | 2125 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ |
059ec3d9 PH |
2126 | |
2127 | /* If verification is optional, don't fail if no certificate */ | |
2128 | ||
7be682ca | 2129 | SSL_CTX_set_verify(sctx, |
5a2a0989 | 2130 | SSL_VERIFY_PEER | (optional ? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 2131 | cert_vfy_cb); |
059ec3d9 PH |
2132 | } |
2133 | ||
2134 | return OK; | |
2135 | } | |
2136 | ||
2137 | ||
2138 | ||
2139 | /************************************************* | |
2140 | * Start a TLS session in a server * | |
2141 | *************************************************/ | |
2142 | ||
2143 | /* This is called when Exim is running as a server, after having received | |
2144 | the STARTTLS command. It must respond to that command, and then negotiate | |
2145 | a TLS session. | |
2146 | ||
2147 | Arguments: | |
2148 | require_ciphers allowed ciphers | |
cf0c6164 | 2149 | errstr pointer to error message |
059ec3d9 PH |
2150 | |
2151 | Returns: OK on success | |
2152 | DEFER for errors before the start of the negotiation | |
4c04137d | 2153 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
2154 | continue running. |
2155 | */ | |
2156 | ||
2157 | int | |
cf0c6164 | 2158 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
2159 | { |
2160 | int rc; | |
cf0c6164 JH |
2161 | uschar * expciphers; |
2162 | tls_ext_ctx_cb * cbinfo; | |
f69979cf | 2163 | static uschar peerdn[256]; |
817d9f57 | 2164 | static uschar cipherbuf[256]; |
059ec3d9 PH |
2165 | |
2166 | /* Check for previous activation */ | |
2167 | ||
74f1a423 | 2168 | if (tls_in.active.sock >= 0) |
059ec3d9 | 2169 | { |
cf0c6164 | 2170 | tls_error(US"STARTTLS received after TLS started", NULL, US"", errstr); |
925ac8e4 | 2171 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
2172 | return FAIL; |
2173 | } | |
2174 | ||
2175 | /* Initialize the SSL library. If it fails, it will already have logged | |
2176 | the error. */ | |
2177 | ||
817d9f57 | 2178 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 2179 | #ifndef DISABLE_OCSP |
47195144 | 2180 | tls_ocsp_file, /*XXX stack*/ |
3f7eeb86 | 2181 | #endif |
cf0c6164 | 2182 | NULL, &server_static_cbinfo, errstr); |
059ec3d9 | 2183 | if (rc != OK) return rc; |
817d9f57 | 2184 | cbinfo = server_static_cbinfo; |
059ec3d9 | 2185 | |
cf0c6164 | 2186 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr)) |
059ec3d9 PH |
2187 | return FAIL; |
2188 | ||
2189 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
2190 | were historically separated by underscores. So that I can use either form in my |
2191 | tests, and also for general convenience, we turn underscores into hyphens here. | |
0c3807a8 JH |
2192 | |
2193 | XXX SSL_CTX_set_cipher_list() is replaced by SSL_CTX_set_ciphersuites() | |
2194 | for TLS 1.3 . Since we do not call it at present we get the default list: | |
2195 | TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256 | |
17c76198 | 2196 | */ |
059ec3d9 | 2197 | |
c3033f13 | 2198 | if (expciphers) |
059ec3d9 | 2199 | { |
c3033f13 | 2200 | uschar * s = expciphers; |
059ec3d9 PH |
2201 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } |
2202 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 2203 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
cf0c6164 | 2204 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr); |
7be682ca | 2205 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
2206 | } |
2207 | ||
2208 | /* If this is a host for which certificate verification is mandatory or | |
2209 | optional, set up appropriately. */ | |
2210 | ||
817d9f57 | 2211 | tls_in.certificate_verified = FALSE; |
c0635b6d | 2212 | #ifdef SUPPORT_DANE |
53a7196b JH |
2213 | tls_in.dane_verified = FALSE; |
2214 | #endif | |
a2ff477a | 2215 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
2216 | |
2217 | if (verify_check_host(&tls_verify_hosts) == OK) | |
2218 | { | |
983207c1 | 2219 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2220 | FALSE, verify_callback_server, errstr); |
059ec3d9 | 2221 | if (rc != OK) return rc; |
a2ff477a | 2222 | server_verify_optional = FALSE; |
059ec3d9 PH |
2223 | } |
2224 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
2225 | { | |
983207c1 | 2226 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2227 | TRUE, verify_callback_server, errstr); |
059ec3d9 | 2228 | if (rc != OK) return rc; |
a2ff477a | 2229 | server_verify_optional = TRUE; |
059ec3d9 PH |
2230 | } |
2231 | ||
2232 | /* Prepare for new connection */ | |
2233 | ||
cf0c6164 JH |
2234 | if (!(server_ssl = SSL_new(server_ctx))) |
2235 | return tls_error(US"SSL_new", NULL, NULL, errstr); | |
da3ad30d PP |
2236 | |
2237 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
2238 | * | |
2239 | * With the SSL_clear(), we get strange interoperability bugs with | |
2240 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
2241 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
2242 | * | |
2243 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
2244 | * session shutdown. In this case, we have a brand new object and there's no | |
2245 | * obvious reason to immediately clear it. I'm guessing that this was | |
2246 | * originally added because of incomplete initialisation which the clear fixed, | |
2247 | * in some historic release. | |
2248 | */ | |
059ec3d9 PH |
2249 | |
2250 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2251 | on connection, where outputting anything now upsets the clients and tends to | |
2252 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2253 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2254 | mode, the fflush() happens when smtp_getc() is called. */ | |
2255 | ||
817d9f57 JH |
2256 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
2257 | if (!tls_in.on_connect) | |
059ec3d9 | 2258 | { |
925ac8e4 | 2259 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
059ec3d9 PH |
2260 | fflush(smtp_out); |
2261 | } | |
2262 | ||
2263 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
2264 | that the OpenSSL library doesn't. */ | |
2265 | ||
817d9f57 JH |
2266 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
2267 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
2268 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
2269 | |
2270 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
2271 | ||
2272 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2273 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
817d9f57 | 2274 | rc = SSL_accept(server_ssl); |
c2a1bba0 | 2275 | ALARM_CLR(0); |
059ec3d9 PH |
2276 | |
2277 | if (rc <= 0) | |
2278 | { | |
cf0c6164 | 2279 | (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr); |
059ec3d9 PH |
2280 | return FAIL; |
2281 | } | |
2282 | ||
2283 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
25fa0868 JH |
2284 | ERR_clear_error(); /* Even success can leave errors in the stack. Seen with |
2285 | anon-authentication ciphersuite negociated. */ | |
059ec3d9 PH |
2286 | |
2287 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2288 | and initialize things. */ | |
2289 | ||
f69979cf JH |
2290 | peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn)); |
2291 | ||
817d9f57 JH |
2292 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
2293 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
2294 | |
2295 | DEBUG(D_tls) | |
2296 | { | |
2297 | uschar buf[2048]; | |
817d9f57 | 2298 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
2299 | debug_printf("Shared ciphers: %s\n", buf); |
2300 | } | |
2301 | ||
9d1c15ef JH |
2302 | /* Record the certificate we presented */ |
2303 | { | |
2304 | X509 * crt = SSL_get_certificate(server_ssl); | |
2305 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
2306 | } | |
059ec3d9 | 2307 | |
817d9f57 JH |
2308 | /* Only used by the server-side tls (tls_in), including tls_getc. |
2309 | Client-side (tls_out) reads (seem to?) go via | |
2310 | smtp_read_response()/ip_recv(). | |
2311 | Hence no need to duplicate for _in and _out. | |
2312 | */ | |
b808677c | 2313 | if (!ssl_xfer_buffer) ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 | 2314 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; |
8b77d27a | 2315 | ssl_xfer_eof = ssl_xfer_error = FALSE; |
059ec3d9 PH |
2316 | |
2317 | receive_getc = tls_getc; | |
0d81dabc | 2318 | receive_getbuf = tls_getbuf; |
584e96c6 | 2319 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2320 | receive_ungetc = tls_ungetc; |
2321 | receive_feof = tls_feof; | |
2322 | receive_ferror = tls_ferror; | |
58eb016e | 2323 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2324 | |
74f1a423 JH |
2325 | tls_in.active.sock = fileno(smtp_out); |
2326 | tls_in.active.tls_ctx = NULL; /* not using explicit ctx for server-side */ | |
059ec3d9 PH |
2327 | return OK; |
2328 | } | |
2329 | ||
2330 | ||
2331 | ||
2332 | ||
043b1248 JH |
2333 | static int |
2334 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
cf0c6164 JH |
2335 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo, |
2336 | uschar ** errstr) | |
043b1248 JH |
2337 | { |
2338 | int rc; | |
94431adb | 2339 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
043b1248 JH |
2340 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only |
2341 | the specified host patterns if one of them is defined */ | |
2342 | ||
610ff438 JH |
2343 | if ( ( !ob->tls_verify_hosts |
2344 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2345 | ) | |
3c07dd2d | 2346 | || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK |
aa2a70ba | 2347 | ) |
043b1248 | 2348 | client_verify_optional = FALSE; |
3c07dd2d | 2349 | else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
2350 | client_verify_optional = TRUE; |
2351 | else | |
2352 | return OK; | |
2353 | ||
2354 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
cf0c6164 JH |
2355 | ob->tls_crl, host, client_verify_optional, verify_callback_client, |
2356 | errstr)) != OK) | |
aa2a70ba | 2357 | return rc; |
043b1248 | 2358 | |
3c07dd2d | 2359 | if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 2360 | { |
4af0d74a | 2361 | cbinfo->verify_cert_hostnames = |
8c5d388a | 2362 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2363 | string_domain_utf8_to_alabel(host->name, NULL); |
2364 | #else | |
2365 | host->name; | |
2366 | #endif | |
aa2a70ba JH |
2367 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", |
2368 | cbinfo->verify_cert_hostnames); | |
043b1248 | 2369 | } |
043b1248 JH |
2370 | return OK; |
2371 | } | |
059ec3d9 | 2372 | |
fde080a4 | 2373 | |
c0635b6d | 2374 | #ifdef SUPPORT_DANE |
fde080a4 | 2375 | static int |
cf0c6164 | 2376 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa, uschar ** errstr) |
fde080a4 JH |
2377 | { |
2378 | dns_record * rr; | |
2379 | dns_scan dnss; | |
2380 | const char * hostnames[2] = { CS host->name, NULL }; | |
2381 | int found = 0; | |
2382 | ||
2383 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
cf0c6164 | 2384 | return tls_error(US"hostnames load", host, NULL, errstr); |
fde080a4 JH |
2385 | |
2386 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); | |
2387 | rr; | |
2388 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
1b76ad22 | 2389 | ) if (rr->type == T_TLSA && rr->size > 3) |
fde080a4 | 2390 | { |
c3033f13 | 2391 | const uschar * p = rr->data; |
fde080a4 JH |
2392 | uint8_t usage, selector, mtype; |
2393 | const char * mdname; | |
2394 | ||
fde080a4 | 2395 | usage = *p++; |
133d2546 JH |
2396 | |
2397 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
2398 | if (usage != 2 && usage != 3) continue; | |
2399 | ||
fde080a4 JH |
2400 | selector = *p++; |
2401 | mtype = *p++; | |
2402 | ||
2403 | switch (mtype) | |
2404 | { | |
133d2546 JH |
2405 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
2406 | case 0: mdname = NULL; break; | |
2407 | case 1: mdname = "sha256"; break; | |
2408 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
2409 | } |
2410 | ||
133d2546 | 2411 | found++; |
fde080a4 JH |
2412 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
2413 | { | |
2414 | default: | |
cf0c6164 | 2415 | return tls_error(US"tlsa load", host, NULL, errstr); |
c035b645 | 2416 | case 0: /* action not taken */ |
fde080a4 JH |
2417 | case 1: break; |
2418 | } | |
594706ea JH |
2419 | |
2420 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
2421 | } |
2422 | ||
2423 | if (found) | |
2424 | return OK; | |
2425 | ||
133d2546 | 2426 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 2427 | return DEFER; |
fde080a4 | 2428 | } |
c0635b6d | 2429 | #endif /*SUPPORT_DANE*/ |
fde080a4 JH |
2430 | |
2431 | ||
2432 | ||
059ec3d9 PH |
2433 | /************************************************* |
2434 | * Start a TLS session in a client * | |
2435 | *************************************************/ | |
2436 | ||
2437 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2438 | ||
2439 | Argument: | |
2440 | fd the fd of the connection | |
afdb5e9c JH |
2441 | host connected host (for messages and option-tests) |
2442 | addr the first address (for some randomness; can be NULL) | |
a7538db1 | 2443 | tb transport (always smtp) |
0e66b3b6 | 2444 | tlsa_dnsa tlsa lookup, if DANE, else null |
afdb5e9c | 2445 | tlsp record details of channel configuration here; must be non-NULL |
cf0c6164 | 2446 | errstr error string pointer |
059ec3d9 | 2447 | |
74f1a423 | 2448 | Returns: Pointer to TLS session context, or NULL on error |
059ec3d9 PH |
2449 | */ |
2450 | ||
74f1a423 | 2451 | void * |
f5d78688 | 2452 | tls_client_start(int fd, host_item *host, address_item *addr, |
cf0c6164 | 2453 | transport_instance * tb, |
c0635b6d | 2454 | #ifdef SUPPORT_DANE |
cf0c6164 | 2455 | dns_answer * tlsa_dnsa, |
0e66b3b6 | 2456 | #endif |
74f1a423 | 2457 | tls_support * tlsp, uschar ** errstr) |
059ec3d9 | 2458 | { |
afdb5e9c JH |
2459 | smtp_transport_options_block * ob = tb |
2460 | ? (smtp_transport_options_block *)tb->options_block | |
2461 | : &smtp_transport_option_defaults; | |
74f1a423 | 2462 | exim_openssl_client_tls_ctx * exim_client_ctx; |
f69979cf | 2463 | static uschar peerdn[256]; |
868f5672 | 2464 | uschar * expciphers; |
059ec3d9 | 2465 | int rc; |
817d9f57 | 2466 | static uschar cipherbuf[256]; |
043b1248 JH |
2467 | |
2468 | #ifndef DISABLE_OCSP | |
043b1248 | 2469 | BOOL request_ocsp = FALSE; |
6634ac8d | 2470 | BOOL require_ocsp = FALSE; |
043b1248 | 2471 | #endif |
043b1248 | 2472 | |
74f1a423 JH |
2473 | rc = store_pool; |
2474 | store_pool = POOL_PERM; | |
2475 | exim_client_ctx = store_get(sizeof(exim_openssl_client_tls_ctx)); | |
2476 | store_pool = rc; | |
2477 | ||
c0635b6d | 2478 | #ifdef SUPPORT_DANE |
74f1a423 | 2479 | tlsp->tlsa_usage = 0; |
043b1248 JH |
2480 | #endif |
2481 | ||
f2de3a33 | 2482 | #ifndef DISABLE_OCSP |
043b1248 | 2483 | { |
c0635b6d | 2484 | # ifdef SUPPORT_DANE |
4f59c424 JH |
2485 | if ( tlsa_dnsa |
2486 | && ob->hosts_request_ocsp[0] == '*' | |
2487 | && ob->hosts_request_ocsp[1] == '\0' | |
2488 | ) | |
2489 | { | |
2490 | /* Unchanged from default. Use a safer one under DANE */ | |
2491 | request_ocsp = TRUE; | |
2492 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
2493 | " {= {4}{$tls_out_tlsa_usage}} } " | |
2494 | " {*}{}}"; | |
2495 | } | |
2496 | # endif | |
2497 | ||
5130845b | 2498 | if ((require_ocsp = |
3c07dd2d | 2499 | verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK)) |
fca41d5a JH |
2500 | request_ocsp = TRUE; |
2501 | else | |
c0635b6d | 2502 | # ifdef SUPPORT_DANE |
4f59c424 | 2503 | if (!request_ocsp) |
fca41d5a | 2504 | # endif |
5130845b | 2505 | request_ocsp = |
3c07dd2d | 2506 | verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
043b1248 | 2507 | } |
f5d78688 | 2508 | #endif |
059ec3d9 | 2509 | |
74f1a423 | 2510 | rc = tls_init(&exim_client_ctx->ctx, host, NULL, |
65867078 | 2511 | ob->tls_certificate, ob->tls_privatekey, |
f2de3a33 | 2512 | #ifndef DISABLE_OCSP |
44662487 | 2513 | (void *)(long)request_ocsp, |
3f7eeb86 | 2514 | #endif |
cf0c6164 | 2515 | addr, &client_static_cbinfo, errstr); |
74f1a423 | 2516 | if (rc != OK) return NULL; |
059ec3d9 | 2517 | |
74f1a423 | 2518 | tlsp->certificate_verified = FALSE; |
a2ff477a | 2519 | client_verify_callback_called = FALSE; |
059ec3d9 | 2520 | |
5ec37a55 PP |
2521 | expciphers = NULL; |
2522 | #ifdef SUPPORT_DANE | |
2523 | if (tlsa_dnsa) | |
2524 | { | |
2525 | /* We fall back to tls_require_ciphers if unset, empty or forced failure, but | |
2526 | other failures should be treated as problems. */ | |
2527 | if (ob->dane_require_tls_ciphers && | |
2528 | !expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2529 | &expciphers, errstr)) | |
74f1a423 | 2530 | return NULL; |
5ec37a55 PP |
2531 | if (expciphers && *expciphers == '\0') |
2532 | expciphers = NULL; | |
2533 | } | |
2534 | #endif | |
2535 | if (!expciphers && | |
2536 | !expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", | |
2537 | &expciphers, errstr)) | |
74f1a423 | 2538 | return NULL; |
059ec3d9 PH |
2539 | |
2540 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
2541 | are separated by underscores. So that I can use either form in my tests, and | |
2542 | also for general convenience, we turn underscores into hyphens here. */ | |
2543 | ||
cf0c6164 | 2544 | if (expciphers) |
059ec3d9 PH |
2545 | { |
2546 | uschar *s = expciphers; | |
cf0c6164 | 2547 | while (*s) { if (*s == '_') *s = '-'; s++; } |
059ec3d9 | 2548 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); |
74f1a423 JH |
2549 | if (!SSL_CTX_set_cipher_list(exim_client_ctx->ctx, CS expciphers)) |
2550 | { | |
2551 | tls_error(US"SSL_CTX_set_cipher_list", host, NULL, errstr); | |
2552 | return NULL; | |
2553 | } | |
059ec3d9 PH |
2554 | } |
2555 | ||
c0635b6d | 2556 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2557 | if (tlsa_dnsa) |
a63be306 | 2558 | { |
74f1a423 | 2559 | SSL_CTX_set_verify(exim_client_ctx->ctx, |
02af313d JH |
2560 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, |
2561 | verify_callback_client_dane); | |
e5cccda9 | 2562 | |
043b1248 | 2563 | if (!DANESSL_library_init()) |
74f1a423 JH |
2564 | { |
2565 | tls_error(US"library init", host, NULL, errstr); | |
2566 | return NULL; | |
2567 | } | |
2568 | if (DANESSL_CTX_init(exim_client_ctx->ctx) <= 0) | |
2569 | { | |
2570 | tls_error(US"context init", host, NULL, errstr); | |
2571 | return NULL; | |
2572 | } | |
043b1248 JH |
2573 | } |
2574 | else | |
e51c7be2 | 2575 | |
043b1248 JH |
2576 | #endif |
2577 | ||
74f1a423 JH |
2578 | if (tls_client_basic_ctx_init(exim_client_ctx->ctx, host, ob, |
2579 | client_static_cbinfo, errstr) != OK) | |
2580 | return NULL; | |
059ec3d9 | 2581 | |
74f1a423 JH |
2582 | if (!(exim_client_ctx->ssl = SSL_new(exim_client_ctx->ctx))) |
2583 | { | |
2584 | tls_error(US"SSL_new", host, NULL, errstr); | |
2585 | return NULL; | |
2586 | } | |
2587 | SSL_set_session_id_context(exim_client_ctx->ssl, sid_ctx, Ustrlen(sid_ctx)); | |
2588 | SSL_set_fd(exim_client_ctx->ssl, fd); | |
2589 | SSL_set_connect_state(exim_client_ctx->ssl); | |
059ec3d9 | 2590 | |
65867078 | 2591 | if (ob->tls_sni) |
3f0945ff | 2592 | { |
74f1a423 JH |
2593 | if (!expand_check(ob->tls_sni, US"tls_sni", &tlsp->sni, errstr)) |
2594 | return NULL; | |
2595 | if (!tlsp->sni) | |
2c9a0e86 PP |
2596 | { |
2597 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
2598 | } | |
74f1a423 JH |
2599 | else if (!Ustrlen(tlsp->sni)) |
2600 | tlsp->sni = NULL; | |
3f0945ff PP |
2601 | else |
2602 | { | |
35731706 | 2603 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
74f1a423 JH |
2604 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tlsp->sni); |
2605 | SSL_set_tlsext_host_name(exim_client_ctx->ssl, tlsp->sni); | |
35731706 | 2606 | #else |
66802652 | 2607 | log_write(0, LOG_MAIN, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n", |
74f1a423 | 2608 | tlsp->sni); |
35731706 | 2609 | #endif |
3f0945ff PP |
2610 | } |
2611 | } | |
2612 | ||
c0635b6d | 2613 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2614 | if (tlsa_dnsa) |
74f1a423 JH |
2615 | if (dane_tlsa_load(exim_client_ctx->ssl, host, tlsa_dnsa, errstr) != OK) |
2616 | return NULL; | |
594706ea JH |
2617 | #endif |
2618 | ||
f2de3a33 | 2619 | #ifndef DISABLE_OCSP |
f5d78688 JH |
2620 | /* Request certificate status at connection-time. If the server |
2621 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
c0635b6d | 2622 | # ifdef SUPPORT_DANE |
594706ea JH |
2623 | if (request_ocsp) |
2624 | { | |
2625 | const uschar * s; | |
41afb5cb JH |
2626 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
2627 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
2628 | ) |
2629 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
2630 | this means we avoid the OCSP request, we wasted the setup | |
2631 | cost in tls_init(). */ | |
3c07dd2d | 2632 | require_ocsp = verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; |
5130845b | 2633 | request_ocsp = require_ocsp |
3c07dd2d | 2634 | || verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
594706ea JH |
2635 | } |
2636 | } | |
b50c8b84 JH |
2637 | # endif |
2638 | ||
44662487 JH |
2639 | if (request_ocsp) |
2640 | { | |
74f1a423 | 2641 | SSL_set_tlsext_status_type(exim_client_ctx->ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 | 2642 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
74f1a423 | 2643 | tlsp->ocsp = OCSP_NOT_RESP; |
44662487 | 2644 | } |
f5d78688 JH |
2645 | #endif |
2646 | ||
0cbf2b82 | 2647 | #ifndef DISABLE_EVENT |
afdb5e9c | 2648 | client_static_cbinfo->event_action = tb ? tb->event_action : NULL; |
a7538db1 | 2649 | #endif |
043b1248 | 2650 | |
059ec3d9 PH |
2651 | /* There doesn't seem to be a built-in timeout on connection. */ |
2652 | ||
2653 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
2654 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2655 | ALARM(ob->command_timeout); |
74f1a423 | 2656 | rc = SSL_connect(exim_client_ctx->ssl); |
c2a1bba0 | 2657 | ALARM_CLR(0); |
059ec3d9 | 2658 | |
c0635b6d | 2659 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2660 | if (tlsa_dnsa) |
74f1a423 | 2661 | DANESSL_cleanup(exim_client_ctx->ssl); |
043b1248 JH |
2662 | #endif |
2663 | ||
059ec3d9 | 2664 | if (rc <= 0) |
74f1a423 JH |
2665 | { |
2666 | tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL, errstr); | |
2667 | return NULL; | |
2668 | } | |
059ec3d9 PH |
2669 | |
2670 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
2671 | ||
74f1a423 | 2672 | peer_cert(exim_client_ctx->ssl, tlsp, peerdn, sizeof(peerdn)); |
059ec3d9 | 2673 | |
74f1a423 JH |
2674 | construct_cipher_name(exim_client_ctx->ssl, cipherbuf, sizeof(cipherbuf), &tlsp->bits); |
2675 | tlsp->cipher = cipherbuf; | |
059ec3d9 | 2676 | |
9d1c15ef JH |
2677 | /* Record the certificate we presented */ |
2678 | { | |
74f1a423 JH |
2679 | X509 * crt = SSL_get_certificate(exim_client_ctx->ssl); |
2680 | tlsp->ourcert = crt ? X509_dup(crt) : NULL; | |
9d1c15ef JH |
2681 | } |
2682 | ||
74f1a423 JH |
2683 | tlsp->active.sock = fd; |
2684 | tlsp->active.tls_ctx = exim_client_ctx; | |
2685 | return exim_client_ctx; | |
059ec3d9 PH |
2686 | } |
2687 | ||
2688 | ||
2689 | ||
2690 | ||
2691 | ||
0d81dabc JH |
2692 | static BOOL |
2693 | tls_refill(unsigned lim) | |
2694 | { | |
2695 | int error; | |
2696 | int inbytes; | |
2697 | ||
2698 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, | |
2699 | ssl_xfer_buffer, ssl_xfer_buffer_size); | |
2700 | ||
c2a1bba0 | 2701 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
0d81dabc JH |
2702 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, |
2703 | MIN(ssl_xfer_buffer_size, lim)); | |
2704 | error = SSL_get_error(server_ssl, inbytes); | |
c2a1bba0 | 2705 | if (smtp_receive_timeout > 0) ALARM_CLR(0); |
9723f966 JH |
2706 | |
2707 | if (had_command_timeout) /* set by signal handler */ | |
2708 | smtp_command_timeout_exit(); /* does not return */ | |
2709 | if (had_command_sigterm) | |
2710 | smtp_command_sigterm_exit(); | |
2711 | if (had_data_timeout) | |
2712 | smtp_data_timeout_exit(); | |
2713 | if (had_data_sigint) | |
2714 | smtp_data_sigint_exit(); | |
0d81dabc JH |
2715 | |
2716 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2717 | closed down, not that the socket itself has been closed down. Revert to | |
2718 | non-SSL handling. */ | |
2719 | ||
74f1a423 | 2720 | switch(error) |
0d81dabc | 2721 | { |
74f1a423 JH |
2722 | case SSL_ERROR_NONE: |
2723 | break; | |
2724 | ||
2725 | case SSL_ERROR_ZERO_RETURN: | |
2726 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
0d81dabc | 2727 | |
74f1a423 JH |
2728 | receive_getc = smtp_getc; |
2729 | receive_getbuf = smtp_getbuf; | |
2730 | receive_get_cache = smtp_get_cache; | |
2731 | receive_ungetc = smtp_ungetc; | |
2732 | receive_feof = smtp_feof; | |
2733 | receive_ferror = smtp_ferror; | |
2734 | receive_smtp_buffered = smtp_buffered; | |
0d81dabc | 2735 | |
74f1a423 JH |
2736 | if (SSL_get_shutdown(server_ssl) == SSL_RECEIVED_SHUTDOWN) |
2737 | SSL_shutdown(server_ssl); | |
dec766a1 | 2738 | |
37f0ce65 | 2739 | #ifndef DISABLE_OCSP |
74f1a423 JH |
2740 | sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free); |
2741 | server_static_cbinfo->verify_stack = NULL; | |
37f0ce65 | 2742 | #endif |
74f1a423 JH |
2743 | SSL_free(server_ssl); |
2744 | SSL_CTX_free(server_ctx); | |
2745 | server_ctx = NULL; | |
2746 | server_ssl = NULL; | |
2747 | tls_in.active.sock = -1; | |
2748 | tls_in.active.tls_ctx = NULL; | |
2749 | tls_in.bits = 0; | |
2750 | tls_in.cipher = NULL; | |
2751 | tls_in.peerdn = NULL; | |
2752 | tls_in.sni = NULL; | |
0d81dabc | 2753 | |
74f1a423 | 2754 | return FALSE; |
0d81dabc | 2755 | |
74f1a423 JH |
2756 | /* Handle genuine errors */ |
2757 | case SSL_ERROR_SSL: | |
0abc5a13 | 2758 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
74f1a423 JH |
2759 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
2760 | ssl_xfer_error = TRUE; | |
2761 | return FALSE; | |
0d81dabc | 2762 | |
74f1a423 JH |
2763 | default: |
2764 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2765 | DEBUG(D_tls) if (error == SSL_ERROR_SYSCALL) | |
2766 | debug_printf(" - syscall %s\n", strerror(errno)); | |
2767 | ssl_xfer_error = TRUE; | |
2768 | return FALSE; | |
0d81dabc JH |
2769 | } |
2770 | ||
2771 | #ifndef DISABLE_DKIM | |
2772 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2773 | #endif | |
2774 | ssl_xfer_buffer_hwm = inbytes; | |
2775 | ssl_xfer_buffer_lwm = 0; | |
2776 | return TRUE; | |
2777 | } | |
2778 | ||
2779 | ||
059ec3d9 PH |
2780 | /************************************************* |
2781 | * TLS version of getc * | |
2782 | *************************************************/ | |
2783 | ||
2784 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2785 | it refills the buffer via the SSL reading function. | |
2786 | ||
bd8fbe36 | 2787 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 | 2788 | Returns: the next character or EOF |
817d9f57 JH |
2789 | |
2790 | Only used by the server-side TLS. | |
059ec3d9 PH |
2791 | */ |
2792 | ||
2793 | int | |
bd8fbe36 | 2794 | tls_getc(unsigned lim) |
059ec3d9 PH |
2795 | { |
2796 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
0d81dabc JH |
2797 | if (!tls_refill(lim)) |
2798 | return ssl_xfer_error ? EOF : smtp_getc(lim); | |
059ec3d9 | 2799 | |
0d81dabc | 2800 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2801 | |
0d81dabc JH |
2802 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; |
2803 | } | |
059ec3d9 | 2804 | |
0d81dabc JH |
2805 | uschar * |
2806 | tls_getbuf(unsigned * len) | |
2807 | { | |
2808 | unsigned size; | |
2809 | uschar * buf; | |
ba084640 | 2810 | |
0d81dabc JH |
2811 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) |
2812 | if (!tls_refill(*len)) | |
059ec3d9 | 2813 | { |
0d81dabc JH |
2814 | if (!ssl_xfer_error) return smtp_getbuf(len); |
2815 | *len = 0; | |
2816 | return NULL; | |
059ec3d9 | 2817 | } |
c80c5570 | 2818 | |
0d81dabc JH |
2819 | if ((size = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm) > *len) |
2820 | size = *len; | |
2821 | buf = &ssl_xfer_buffer[ssl_xfer_buffer_lwm]; | |
2822 | ssl_xfer_buffer_lwm += size; | |
2823 | *len = size; | |
2824 | return buf; | |
059ec3d9 PH |
2825 | } |
2826 | ||
0d81dabc | 2827 | |
584e96c6 JH |
2828 | void |
2829 | tls_get_cache() | |
2830 | { | |
9960d1e5 | 2831 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2832 | int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm; |
2833 | if (n > 0) | |
2834 | dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n); | |
584e96c6 | 2835 | #endif |
9960d1e5 | 2836 | } |
584e96c6 | 2837 | |
059ec3d9 | 2838 | |
925ac8e4 JH |
2839 | BOOL |
2840 | tls_could_read(void) | |
2841 | { | |
a5ffa9b4 | 2842 | return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(server_ssl) > 0; |
925ac8e4 JH |
2843 | } |
2844 | ||
059ec3d9 PH |
2845 | |
2846 | /************************************************* | |
2847 | * Read bytes from TLS channel * | |
2848 | *************************************************/ | |
2849 | ||
2850 | /* | |
2851 | Arguments: | |
74f1a423 | 2852 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2853 | buff buffer of data |
2854 | len size of buffer | |
2855 | ||
2856 | Returns: the number of bytes read | |
afdb5e9c | 2857 | -1 after a failed read, including EOF |
817d9f57 JH |
2858 | |
2859 | Only used by the client-side TLS. | |
059ec3d9 PH |
2860 | */ |
2861 | ||
2862 | int | |
74f1a423 | 2863 | tls_read(void * ct_ctx, uschar *buff, size_t len) |
059ec3d9 | 2864 | { |
74f1a423 | 2865 | SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; |
059ec3d9 PH |
2866 | int inbytes; |
2867 | int error; | |
2868 | ||
389ca47a | 2869 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2870 | buff, (unsigned int)len); |
059ec3d9 | 2871 | |
389ca47a JH |
2872 | inbytes = SSL_read(ssl, CS buff, len); |
2873 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2874 | |
2875 | if (error == SSL_ERROR_ZERO_RETURN) | |
2876 | { | |
2877 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2878 | return -1; | |
2879 | } | |
2880 | else if (error != SSL_ERROR_NONE) | |
059ec3d9 | 2881 | return -1; |
059ec3d9 PH |
2882 | |
2883 | return inbytes; | |
2884 | } | |
2885 | ||
2886 | ||
2887 | ||
2888 | ||
2889 | ||
2890 | /************************************************* | |
2891 | * Write bytes down TLS channel * | |
2892 | *************************************************/ | |
2893 | ||
2894 | /* | |
2895 | Arguments: | |
74f1a423 | 2896 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2897 | buff buffer of data |
2898 | len number of bytes | |
925ac8e4 | 2899 | more further data expected soon |
059ec3d9 PH |
2900 | |
2901 | Returns: the number of bytes after a successful write, | |
2902 | -1 after a failed write | |
817d9f57 JH |
2903 | |
2904 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2905 | */ |
2906 | ||
2907 | int | |
74f1a423 | 2908 | tls_write(void * ct_ctx, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2909 | { |
a5ffa9b4 | 2910 | int outbytes, error, left; |
74f1a423 | 2911 | SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; |
acec9514 | 2912 | static gstring * corked = NULL; |
a5ffa9b4 | 2913 | |
ef698bf6 | 2914 | DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__, |
b93be52e | 2915 | buff, (unsigned long)len, more ? ", more" : ""); |
a5ffa9b4 JH |
2916 | |
2917 | /* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when | |
2918 | "more" is notified. This hack is only ok if small amounts are involved AND only | |
2919 | one stream does it, in one context (i.e. no store reset). Currently it is used | |
2920 | for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. */ | |
ee8b8090 JH |
2921 | /*XXX + if PIPE_COMMAND, banner & ehlo-resp for smmtp-on-connect. Suspect there's |
2922 | a store reset there. */ | |
a5ffa9b4 | 2923 | |
74f1a423 | 2924 | if (!ct_ctx && (more || corked)) |
a5ffa9b4 | 2925 | { |
ee8b8090 JH |
2926 | #ifdef EXPERIMENTAL_PIPE_CONNECT |
2927 | int save_pool = store_pool; | |
2928 | store_pool = POOL_PERM; | |
2929 | #endif | |
2930 | ||
acec9514 | 2931 | corked = string_catn(corked, buff, len); |
ee8b8090 JH |
2932 | |
2933 | #ifdef EXPERIMENTAL_PIPE_CONNECT | |
2934 | store_pool = save_pool; | |
2935 | #endif | |
2936 | ||
a5ffa9b4 JH |
2937 | if (more) |
2938 | return len; | |
acec9514 JH |
2939 | buff = CUS corked->s; |
2940 | len = corked->ptr; | |
2941 | corked = NULL; | |
a5ffa9b4 | 2942 | } |
059ec3d9 | 2943 | |
a5ffa9b4 | 2944 | for (left = len; left > 0;) |
059ec3d9 | 2945 | { |
74f1a423 | 2946 | DEBUG(D_tls) debug_printf("SSL_write(%p, %p, %d)\n", ssl, buff, left); |
059ec3d9 PH |
2947 | outbytes = SSL_write(ssl, CS buff, left); |
2948 | error = SSL_get_error(ssl, outbytes); | |
2949 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2950 | switch (error) | |
2951 | { | |
2952 | case SSL_ERROR_SSL: | |
0abc5a13 | 2953 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
96f5fe4c JH |
2954 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); |
2955 | return -1; | |
059ec3d9 PH |
2956 | |
2957 | case SSL_ERROR_NONE: | |
96f5fe4c JH |
2958 | left -= outbytes; |
2959 | buff += outbytes; | |
2960 | break; | |
059ec3d9 PH |
2961 | |
2962 | case SSL_ERROR_ZERO_RETURN: | |
96f5fe4c JH |
2963 | log_write(0, LOG_MAIN, "SSL channel closed on write"); |
2964 | return -1; | |
059ec3d9 | 2965 | |
817d9f57 | 2966 | case SSL_ERROR_SYSCALL: |
96f5fe4c JH |
2967 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", |
2968 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
2969 | strerror(errno)); | |
2970 | return -1; | |
817d9f57 | 2971 | |
059ec3d9 | 2972 | default: |
96f5fe4c JH |
2973 | log_write(0, LOG_MAIN, "SSL_write error %d", error); |
2974 | return -1; | |
059ec3d9 PH |
2975 | } |
2976 | } | |
2977 | return len; | |
2978 | } | |
2979 | ||
2980 | ||
2981 | ||
2982 | /************************************************* | |
2983 | * Close down a TLS session * | |
2984 | *************************************************/ | |
2985 | ||
2986 | /* This is also called from within a delivery subprocess forked from the | |
2987 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2988 | would tamper with the SSL session in the parent process). | |
2989 | ||
dec766a1 | 2990 | Arguments: |
74f1a423 | 2991 | ct_ctx client TLS context pointer, or NULL for the one global server context |
dec766a1 WB |
2992 | shutdown 1 if TLS close-alert is to be sent, |
2993 | 2 if also response to be waited for | |
2994 | ||
059ec3d9 | 2995 | Returns: nothing |
817d9f57 JH |
2996 | |
2997 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2998 | */ |
2999 | ||
3000 | void | |
74f1a423 | 3001 | tls_close(void * ct_ctx, int shutdown) |
059ec3d9 | 3002 | { |
74f1a423 JH |
3003 | exim_openssl_client_tls_ctx * o_ctx = ct_ctx; |
3004 | SSL_CTX **ctxp = o_ctx ? &o_ctx->ctx : &server_ctx; | |
3005 | SSL **sslp = o_ctx ? &o_ctx->ssl : &server_ssl; | |
3006 | int *fdp = o_ctx ? &tls_out.active.sock : &tls_in.active.sock; | |
817d9f57 JH |
3007 | |
3008 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
3009 | |
3010 | if (shutdown) | |
3011 | { | |
dec766a1 WB |
3012 | int rc; |
3013 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", | |
3014 | shutdown > 1 ? " (with response-wait)" : ""); | |
3015 | ||
3016 | if ( (rc = SSL_shutdown(*sslp)) == 0 /* send "close notify" alert */ | |
3017 | && shutdown > 1) | |
3018 | { | |
c2a1bba0 | 3019 | ALARM(2); |
dec766a1 | 3020 | rc = SSL_shutdown(*sslp); /* wait for response */ |
c2a1bba0 | 3021 | ALARM_CLR(0); |
dec766a1 WB |
3022 | } |
3023 | ||
3024 | if (rc < 0) DEBUG(D_tls) | |
3025 | { | |
0abc5a13 | 3026 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
dec766a1 WB |
3027 | debug_printf("SSL_shutdown: %s\n", ssl_errstring); |
3028 | } | |
3029 | } | |
3030 | ||
37f0ce65 | 3031 | #ifndef DISABLE_OCSP |
74f1a423 | 3032 | if (!o_ctx) /* server side */ |
dec766a1 WB |
3033 | { |
3034 | sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free); | |
dec766a1 | 3035 | server_static_cbinfo->verify_stack = NULL; |
059ec3d9 | 3036 | } |
37f0ce65 | 3037 | #endif |
059ec3d9 | 3038 | |
dec766a1 | 3039 | SSL_CTX_free(*ctxp); |
817d9f57 | 3040 | SSL_free(*sslp); |
dec766a1 | 3041 | *ctxp = NULL; |
817d9f57 | 3042 | *sslp = NULL; |
817d9f57 | 3043 | *fdp = -1; |
059ec3d9 PH |
3044 | } |
3045 | ||
36f12725 NM |
3046 | |
3047 | ||
3048 | ||
3375e053 PP |
3049 | /************************************************* |
3050 | * Let tls_require_ciphers be checked at startup * | |
3051 | *************************************************/ | |
3052 | ||
3053 | /* The tls_require_ciphers option, if set, must be something which the | |
3054 | library can parse. | |
3055 | ||
3056 | Returns: NULL on success, or error message | |
3057 | */ | |
3058 | ||
3059 | uschar * | |
3060 | tls_validate_require_cipher(void) | |
3061 | { | |
3062 | SSL_CTX *ctx; | |
3063 | uschar *s, *expciphers, *err; | |
3064 | ||
3065 | /* this duplicates from tls_init(), we need a better "init just global | |
3066 | state, for no specific purpose" singleton function of our own */ | |
3067 | ||
7434882d | 3068 | #ifdef EXIM_NEED_OPENSSL_INIT |
3375e053 PP |
3069 | SSL_load_error_strings(); |
3070 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 3071 | #endif |
3375e053 PP |
3072 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
3073 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
3074 | list of available digests. */ | |
3075 | EVP_add_digest(EVP_sha256()); | |
3076 | #endif | |
3077 | ||
3078 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
3079 | return NULL; | |
3080 | ||
cf0c6164 JH |
3081 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
3082 | &err)) | |
3375e053 PP |
3083 | return US"failed to expand tls_require_ciphers"; |
3084 | ||
3085 | if (!(expciphers && *expciphers)) | |
3086 | return NULL; | |
3087 | ||
3088 | /* normalisation ripped from above */ | |
3089 | s = expciphers; | |
3090 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
3091 | ||
3092 | err = NULL; | |
3093 | ||
7a8b9519 JH |
3094 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
3095 | if (!(ctx = SSL_CTX_new(TLS_server_method()))) | |
3096 | #else | |
3097 | if (!(ctx = SSL_CTX_new(SSLv23_server_method()))) | |
3098 | #endif | |
3375e053 | 3099 | { |
0abc5a13 | 3100 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3375e053 PP |
3101 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); |
3102 | } | |
3103 | ||
3104 | DEBUG(D_tls) | |
3105 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
3106 | ||
3107 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
3108 | { | |
0abc5a13 | 3109 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 JH |
3110 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s", |
3111 | expciphers, ssl_errstring); | |
3375e053 PP |
3112 | } |
3113 | ||
3114 | SSL_CTX_free(ctx); | |
3115 | ||
3116 | return err; | |
3117 | } | |
3118 | ||
3119 | ||
3120 | ||
3121 | ||
36f12725 NM |
3122 | /************************************************* |
3123 | * Report the library versions. * | |
3124 | *************************************************/ | |
3125 | ||
3126 | /* There have historically been some issues with binary compatibility in | |
3127 | OpenSSL libraries; if Exim (like many other applications) is built against | |
3128 | one version of OpenSSL but the run-time linker picks up another version, | |
3129 | it can result in serious failures, including crashing with a SIGSEGV. So | |
3130 | report the version found by the compiler and the run-time version. | |
3131 | ||
f64a1e23 PP |
3132 | Note: some OS vendors backport security fixes without changing the version |
3133 | number/string, and the version date remains unchanged. The _build_ date | |
3134 | will change, so we can more usefully assist with version diagnosis by also | |
3135 | reporting the build date. | |
3136 | ||
36f12725 NM |
3137 | Arguments: a FILE* to print the results to |
3138 | Returns: nothing | |
3139 | */ | |
3140 | ||
3141 | void | |
3142 | tls_version_report(FILE *f) | |
3143 | { | |
754a0503 | 3144 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
3145 | " Runtime: %s\n" |
3146 | " : %s\n", | |
754a0503 | 3147 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
3148 | SSLeay_version(SSLEAY_VERSION), |
3149 | SSLeay_version(SSLEAY_BUILT_ON)); | |
3150 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
3151 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
3152 | } |
3153 | ||
9e3331ea TK |
3154 | |
3155 | ||
3156 | ||
3157 | /************************************************* | |
17c76198 | 3158 | * Random number generation * |
9e3331ea TK |
3159 | *************************************************/ |
3160 | ||
3161 | /* Pseudo-random number generation. The result is not expected to be | |
3162 | cryptographically strong but not so weak that someone will shoot themselves | |
3163 | in the foot using it as a nonce in input in some email header scheme or | |
3164 | whatever weirdness they'll twist this into. The result should handle fork() | |
3165 | and avoid repeating sequences. OpenSSL handles that for us. | |
3166 | ||
3167 | Arguments: | |
3168 | max range maximum | |
3169 | Returns a random number in range [0, max-1] | |
3170 | */ | |
3171 | ||
3172 | int | |
17c76198 | 3173 | vaguely_random_number(int max) |
9e3331ea TK |
3174 | { |
3175 | unsigned int r; | |
3176 | int i, needed_len; | |
de6135a0 PP |
3177 | static pid_t pidlast = 0; |
3178 | pid_t pidnow; | |
9e3331ea TK |
3179 | uschar *p; |
3180 | uschar smallbuf[sizeof(r)]; | |
3181 | ||
3182 | if (max <= 1) | |
3183 | return 0; | |
3184 | ||
de6135a0 PP |
3185 | pidnow = getpid(); |
3186 | if (pidnow != pidlast) | |
3187 | { | |
3188 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
3189 | is unique for each thread", this doesn't apparently apply across processes, | |
3190 | so our own warning from vaguely_random_number_fallback() applies here too. | |
3191 | Fix per PostgreSQL. */ | |
3192 | if (pidlast != 0) | |
3193 | RAND_cleanup(); | |
3194 | pidlast = pidnow; | |
3195 | } | |
3196 | ||
9e3331ea TK |
3197 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
3198 | if (!RAND_status()) | |
3199 | { | |
3200 | randstuff r; | |
3201 | gettimeofday(&r.tv, NULL); | |
3202 | r.p = getpid(); | |
3203 | ||
5903c6ff | 3204 | RAND_seed(US (&r), sizeof(r)); |
9e3331ea TK |
3205 | } |
3206 | /* We're after pseudo-random, not random; if we still don't have enough data | |
3207 | in the internal PRNG then our options are limited. We could sleep and hope | |
3208 | for entropy to come along (prayer technique) but if the system is so depleted | |
3209 | in the first place then something is likely to just keep taking it. Instead, | |
3210 | we'll just take whatever little bit of pseudo-random we can still manage to | |
3211 | get. */ | |
3212 | ||
3213 | needed_len = sizeof(r); | |
3214 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
3215 | asked for a number less than 10. */ | |
3216 | for (r = max, i = 0; r; ++i) | |
3217 | r >>= 1; | |
3218 | i = (i + 7) / 8; | |
3219 | if (i < needed_len) | |
3220 | needed_len = i; | |
3221 | ||
c8dfb21d | 3222 | #ifdef EXIM_HAVE_RAND_PSEUDO |
9e3331ea | 3223 | /* We do not care if crypto-strong */ |
17c76198 | 3224 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
c8dfb21d JH |
3225 | #else |
3226 | i = RAND_bytes(smallbuf, needed_len); | |
3227 | #endif | |
3228 | ||
17c76198 PP |
3229 | if (i < 0) |
3230 | { | |
3231 | DEBUG(D_all) | |
3232 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
3233 | return vaguely_random_number_fallback(max); | |
3234 | } | |
3235 | ||
9e3331ea TK |
3236 | r = 0; |
3237 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
3238 | { | |
3239 | r *= 256; | |
3240 | r += *p; | |
3241 | } | |
3242 | ||
3243 | /* We don't particularly care about weighted results; if someone wants | |
3244 | smooth distribution and cares enough then they should submit a patch then. */ | |
3245 | return r % max; | |
3246 | } | |
3247 | ||
77bb000f PP |
3248 | |
3249 | ||
3250 | ||
3251 | /************************************************* | |
3252 | * OpenSSL option parse * | |
3253 | *************************************************/ | |
3254 | ||
3255 | /* Parse one option for tls_openssl_options_parse below | |
3256 | ||
3257 | Arguments: | |
3258 | name one option name | |
3259 | value place to store a value for it | |
3260 | Returns success or failure in parsing | |
3261 | */ | |
3262 | ||
77bb000f | 3263 | |
c80c5570 | 3264 | |
77bb000f PP |
3265 | static BOOL |
3266 | tls_openssl_one_option_parse(uschar *name, long *value) | |
3267 | { | |
3268 | int first = 0; | |
3269 | int last = exim_openssl_options_size; | |
3270 | while (last > first) | |
3271 | { | |
3272 | int middle = (first + last)/2; | |
3273 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
3274 | if (c == 0) | |
3275 | { | |
3276 | *value = exim_openssl_options[middle].value; | |
3277 | return TRUE; | |
3278 | } | |
3279 | else if (c > 0) | |
3280 | first = middle + 1; | |
3281 | else | |
3282 | last = middle; | |
3283 | } | |
3284 | return FALSE; | |
3285 | } | |
3286 | ||
3287 | ||
3288 | ||
3289 | ||
3290 | /************************************************* | |
3291 | * OpenSSL option parsing logic * | |
3292 | *************************************************/ | |
3293 | ||
3294 | /* OpenSSL has a number of compatibility options which an administrator might | |
3295 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
3296 | we look like log_selector. | |
3297 | ||
3298 | Arguments: | |
3299 | option_spec the administrator-supplied string of options | |
3300 | results ptr to long storage for the options bitmap | |
3301 | Returns success or failure | |
3302 | */ | |
3303 | ||
3304 | BOOL | |
3305 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
3306 | { | |
3307 | long result, item; | |
3308 | uschar *s, *end; | |
3309 | uschar keep_c; | |
3310 | BOOL adding, item_parsed; | |
3311 | ||
7006ee24 | 3312 | result = SSL_OP_NO_TICKET; |
b1770b6e | 3313 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 3314 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
3315 | #ifdef SSL_OP_NO_SSLv2 |
3316 | result |= SSL_OP_NO_SSLv2; | |
3317 | #endif | |
a57b6200 JH |
3318 | #ifdef SSL_OP_SINGLE_DH_USE |
3319 | result |= SSL_OP_SINGLE_DH_USE; | |
3320 | #endif | |
77bb000f | 3321 | |
7006ee24 | 3322 | if (!option_spec) |
77bb000f PP |
3323 | { |
3324 | *results = result; | |
3325 | return TRUE; | |
3326 | } | |
3327 | ||
3328 | for (s=option_spec; *s != '\0'; /**/) | |
3329 | { | |
3330 | while (isspace(*s)) ++s; | |
3331 | if (*s == '\0') | |
3332 | break; | |
3333 | if (*s != '+' && *s != '-') | |
3334 | { | |
3335 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 3336 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
3337 | return FALSE; |
3338 | } | |
3339 | adding = *s++ == '+'; | |
3340 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
3341 | keep_c = *end; | |
3342 | *end = '\0'; | |
3343 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
96f5fe4c | 3344 | *end = keep_c; |
77bb000f PP |
3345 | if (!item_parsed) |
3346 | { | |
0e944a0d | 3347 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
3348 | return FALSE; |
3349 | } | |
3350 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
3351 | adding ? "adding" : "removing", result, item, s); | |
3352 | if (adding) | |
3353 | result |= item; | |
3354 | else | |
3355 | result &= ~item; | |
77bb000f PP |
3356 | s = end; |
3357 | } | |
3358 | ||
3359 | *results = result; | |
3360 | return TRUE; | |
3361 | } | |
3362 | ||
8442641e | 3363 | #endif /*!MACRO_PREDEF*/ |
9d1c15ef JH |
3364 | /* vi: aw ai sw=2 |
3365 | */ | |
059ec3d9 | 3366 | /* End of tls-openssl.c */ |