Commit | Line | Data |
---|---|---|
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 | 56 | |
d7978c0f JH |
57 | /* X509_check_host provides sane certificate hostname checking, but was added |
58 | to OpenSSL late, after other projects forked off the code-base. So in | |
59 | addition to guarding against the base version number, beware that LibreSSL | |
60 | does not (at this time) support this function. | |
61 | ||
62 | If LibreSSL gains a different API, perhaps via libtls, then we'll probably | |
63 | opt to disentangle and ask a LibreSSL user to provide glue for a third | |
64 | crypto provider for libtls instead of continuing to tie the OpenSSL glue | |
65 | into even twistier knots. If LibreSSL gains the same API, we can just | |
66 | change this guard and punt the issue for a while longer. */ | |
67 | ||
34e3241d PP |
68 | #ifndef LIBRESSL_VERSION_NUMBER |
69 | # if OPENSSL_VERSION_NUMBER >= 0x010100000L | |
70 | # define EXIM_HAVE_OPENSSL_CHECKHOST | |
8420742d | 71 | # define EXIM_HAVE_OPENSSL_DH_BITS |
7a8b9519 | 72 | # define EXIM_HAVE_OPENSSL_TLS_METHOD |
f20cfa4a | 73 | # define EXIM_HAVE_OPENSSL_KEYLOG |
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 | |
8a40db1c JH |
95 | #ifndef LIBRESSL_VERSION_NUMBER |
96 | # if OPENSSL_VERSION_NUMBER >= 0x010101000L | |
97 | # define OPENSSL_HAVE_KEYLOG_CB | |
d7f31bb6 | 98 | # define OPENSSL_HAVE_NUM_TICKETS |
8a40db1c JH |
99 | # endif |
100 | #endif | |
101 | ||
67791ce4 JH |
102 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
103 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
104 | # define DISABLE_OCSP | |
105 | #endif | |
106 | ||
a6510420 JH |
107 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
108 | # include <openssl/x509v3.h> | |
109 | #endif | |
110 | ||
8442641e JH |
111 | /************************************************* |
112 | * OpenSSL option parse * | |
113 | *************************************************/ | |
114 | ||
115 | typedef struct exim_openssl_option { | |
116 | uschar *name; | |
117 | long value; | |
118 | } exim_openssl_option; | |
119 | /* We could use a macro to expand, but we need the ifdef and not all the | |
120 | options document which version they were introduced in. Policylet: include | |
121 | all options unless explicitly for DTLS, let the administrator choose which | |
122 | to apply. | |
123 | ||
124 | This list is current as of: | |
125 | ==> 1.0.1b <== | |
126 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
127 | Plus SSL_OP_NO_TLSv1_3 for 1.1.2-dev | |
128 | */ | |
129 | static exim_openssl_option exim_openssl_options[] = { | |
130 | /* KEEP SORTED ALPHABETICALLY! */ | |
131 | #ifdef SSL_OP_ALL | |
132 | { US"all", SSL_OP_ALL }, | |
133 | #endif | |
134 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
135 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, | |
136 | #endif | |
137 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
138 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, | |
139 | #endif | |
140 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
141 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, | |
142 | #endif | |
143 | #ifdef SSL_OP_EPHEMERAL_RSA | |
144 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, | |
145 | #endif | |
146 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
147 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, | |
148 | #endif | |
149 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
150 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, | |
151 | #endif | |
152 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
153 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, | |
154 | #endif | |
155 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
156 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, | |
157 | #endif | |
158 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
159 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, | |
160 | #endif | |
161 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
162 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, | |
163 | #endif | |
164 | #ifdef SSL_OP_NO_COMPRESSION | |
165 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
166 | #endif | |
167 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION | |
168 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, | |
169 | #endif | |
170 | #ifdef SSL_OP_NO_SSLv2 | |
171 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
172 | #endif | |
173 | #ifdef SSL_OP_NO_SSLv3 | |
174 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
175 | #endif | |
176 | #ifdef SSL_OP_NO_TICKET | |
177 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
178 | #endif | |
179 | #ifdef SSL_OP_NO_TLSv1 | |
180 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
181 | #endif | |
182 | #ifdef SSL_OP_NO_TLSv1_1 | |
183 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
184 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
185 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
186 | #else | |
187 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
188 | #endif | |
189 | #endif | |
190 | #ifdef SSL_OP_NO_TLSv1_2 | |
191 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
192 | #endif | |
193 | #ifdef SSL_OP_NO_TLSv1_3 | |
194 | { US"no_tlsv1_3", SSL_OP_NO_TLSv1_3 }, | |
195 | #endif | |
196 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG | |
197 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
198 | #endif | |
199 | #ifdef SSL_OP_SINGLE_DH_USE | |
200 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, | |
201 | #endif | |
202 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
203 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, | |
204 | #endif | |
205 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
206 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, | |
207 | #endif | |
208 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
209 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, | |
210 | #endif | |
211 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
212 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, | |
213 | #endif | |
214 | #ifdef SSL_OP_TLS_D5_BUG | |
215 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, | |
216 | #endif | |
217 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
218 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, | |
219 | #endif | |
220 | }; | |
221 | ||
222 | #ifndef MACRO_PREDEF | |
223 | static int exim_openssl_options_size = nelem(exim_openssl_options); | |
224 | #endif | |
225 | ||
226 | #ifdef MACRO_PREDEF | |
227 | void | |
228 | options_tls(void) | |
229 | { | |
8442641e JH |
230 | uschar buf[64]; |
231 | ||
d7978c0f | 232 | for (struct exim_openssl_option * o = exim_openssl_options; |
8442641e JH |
233 | o < exim_openssl_options + nelem(exim_openssl_options); o++) |
234 | { | |
235 | /* Trailing X is workaround for problem with _OPT_OPENSSL_NO_TLSV1 | |
236 | being a ".ifdef _OPT_OPENSSL_NO_TLSV1_3" match */ | |
237 | ||
238 | spf(buf, sizeof(buf), US"_OPT_OPENSSL_%T_X", o->name); | |
239 | builtin_macro_create(buf); | |
240 | } | |
241 | } | |
242 | #else | |
243 | ||
244 | /******************************************************************************/ | |
245 | ||
059ec3d9 PH |
246 | /* Structure for collecting random data for seeding. */ |
247 | ||
248 | typedef struct randstuff { | |
9e3331ea TK |
249 | struct timeval tv; |
250 | pid_t p; | |
059ec3d9 PH |
251 | } randstuff; |
252 | ||
253 | /* Local static variables */ | |
254 | ||
a2ff477a JH |
255 | static BOOL client_verify_callback_called = FALSE; |
256 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
257 | static const uschar *sid_ctx = US"exim"; |
258 | ||
d4f09789 PP |
259 | /* We have three different contexts to care about. |
260 | ||
261 | Simple case: client, `client_ctx` | |
262 | As a client, we can be doing a callout or cut-through delivery while receiving | |
263 | a message. So we have a client context, which should have options initialised | |
74f1a423 JH |
264 | from the SMTP Transport. We may also concurrently want to make TLS connections |
265 | to utility daemons, so client-contexts are allocated and passed around in call | |
266 | args rather than using a gobal. | |
d4f09789 PP |
267 | |
268 | Server: | |
269 | There are two cases: with and without ServerNameIndication from the client. | |
270 | Given TLS SNI, we can be using different keys, certs and various other | |
271 | configuration settings, because they're re-expanded with $tls_sni set. This | |
272 | allows vhosting with TLS. This SNI is sent in the handshake. | |
273 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
274 | So as a server, we start out using `server_ctx`. | |
275 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
276 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
277 | configuration. | |
278 | */ | |
279 | ||
74f1a423 JH |
280 | typedef struct { |
281 | SSL_CTX * ctx; | |
282 | SSL * ssl; | |
283 | } exim_openssl_client_tls_ctx; | |
284 | ||
817d9f57 | 285 | static SSL_CTX *server_ctx = NULL; |
817d9f57 | 286 | static SSL *server_ssl = NULL; |
389ca47a | 287 | |
35731706 | 288 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 289 | static SSL_CTX *server_sni = NULL; |
35731706 | 290 | #endif |
059ec3d9 PH |
291 | |
292 | static char ssl_errstring[256]; | |
293 | ||
294 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
295 | static BOOL client_verify_optional = FALSE; |
296 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 297 | |
f5d78688 | 298 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
299 | |
300 | ||
7be682ca PP |
301 | typedef struct tls_ext_ctx_cb { |
302 | uschar *certificate; | |
303 | uschar *privatekey; | |
f5d78688 | 304 | BOOL is_server; |
a6510420 | 305 | #ifndef DISABLE_OCSP |
c3033f13 | 306 | STACK_OF(X509) *verify_stack; /* chain for verifying the proof */ |
f5d78688 JH |
307 | union { |
308 | struct { | |
309 | uschar *file; | |
310 | uschar *file_expanded; | |
311 | OCSP_RESPONSE *response; | |
312 | } server; | |
313 | struct { | |
44662487 JH |
314 | X509_STORE *verify_store; /* non-null if status requested */ |
315 | BOOL verify_required; | |
f5d78688 JH |
316 | } client; |
317 | } u_ocsp; | |
3f7eeb86 | 318 | #endif |
7be682ca PP |
319 | uschar *dhparam; |
320 | /* these are cached from first expand */ | |
321 | uschar *server_cipher_list; | |
322 | /* only passed down to tls_error: */ | |
323 | host_item *host; | |
55414b25 | 324 | const uschar * verify_cert_hostnames; |
0cbf2b82 | 325 | #ifndef DISABLE_EVENT |
a7538db1 JH |
326 | uschar * event_action; |
327 | #endif | |
7be682ca PP |
328 | } tls_ext_ctx_cb; |
329 | ||
330 | /* should figure out a cleanup of API to handle state preserved per | |
331 | implementation, for various reasons, which can be void * in the APIs. | |
332 | For now, we hack around it. */ | |
817d9f57 JH |
333 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
334 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
335 | |
336 | static int | |
983207c1 | 337 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 338 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr ); |
059ec3d9 | 339 | |
3f7eeb86 | 340 | /* Callbacks */ |
3bcbbbe2 | 341 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 342 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 343 | #endif |
f2de3a33 | 344 | #ifndef DISABLE_OCSP |
f5d78688 | 345 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
346 | #endif |
347 | ||
059ec3d9 PH |
348 | |
349 | /************************************************* | |
350 | * Handle TLS error * | |
351 | *************************************************/ | |
352 | ||
353 | /* Called from lots of places when errors occur before actually starting to do | |
354 | the TLS handshake, that is, while the session is still in clear. Always returns | |
355 | DEFER for a server and FAIL for a client so that most calls can use "return | |
356 | tls_error(...)" to do this processing and then give an appropriate return. A | |
357 | single function is used for both server and client, because it is called from | |
358 | some shared functions. | |
359 | ||
360 | Argument: | |
361 | prefix text to include in the logged error | |
362 | host NULL if setting up a server; | |
363 | the connected host if setting up a client | |
7199e1ee | 364 | msg error message or NULL if we should ask OpenSSL |
cf0c6164 | 365 | errstr pointer to output error message |
059ec3d9 PH |
366 | |
367 | Returns: OK/DEFER/FAIL | |
368 | */ | |
369 | ||
370 | static int | |
cf0c6164 | 371 | tls_error(uschar * prefix, const host_item * host, uschar * msg, uschar ** errstr) |
059ec3d9 | 372 | { |
c562fd30 | 373 | if (!msg) |
7199e1ee | 374 | { |
0abc5a13 | 375 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 | 376 | msg = US ssl_errstring; |
7199e1ee TF |
377 | } |
378 | ||
5a2a0989 JH |
379 | msg = string_sprintf("(%s): %s", prefix, msg); |
380 | DEBUG(D_tls) debug_printf("TLS error '%s'\n", msg); | |
381 | if (errstr) *errstr = msg; | |
cf0c6164 | 382 | return host ? FAIL : DEFER; |
059ec3d9 PH |
383 | } |
384 | ||
385 | ||
386 | ||
387 | /************************************************* | |
388 | * Callback to generate RSA key * | |
389 | *************************************************/ | |
390 | ||
391 | /* | |
392 | Arguments: | |
3ae79556 | 393 | s SSL connection (not used) |
059ec3d9 PH |
394 | export not used |
395 | keylength keylength | |
396 | ||
397 | Returns: pointer to generated key | |
398 | */ | |
399 | ||
400 | static RSA * | |
401 | rsa_callback(SSL *s, int export, int keylength) | |
402 | { | |
403 | RSA *rsa_key; | |
c8dfb21d JH |
404 | #ifdef EXIM_HAVE_RSA_GENKEY_EX |
405 | BIGNUM *bn = BN_new(); | |
406 | #endif | |
407 | ||
059ec3d9 PH |
408 | export = export; /* Shut picky compilers up */ |
409 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
c8dfb21d JH |
410 | |
411 | #ifdef EXIM_HAVE_RSA_GENKEY_EX | |
412 | if ( !BN_set_word(bn, (unsigned long)RSA_F4) | |
f2cb6292 | 413 | || !(rsa_key = RSA_new()) |
c8dfb21d JH |
414 | || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL) |
415 | ) | |
416 | #else | |
23bb6982 | 417 | if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL))) |
c8dfb21d JH |
418 | #endif |
419 | ||
059ec3d9 | 420 | { |
0abc5a13 | 421 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
059ec3d9 PH |
422 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", |
423 | ssl_errstring); | |
424 | return NULL; | |
425 | } | |
426 | return rsa_key; | |
427 | } | |
428 | ||
429 | ||
430 | ||
f5d78688 | 431 | /* Extreme debug |
f2de3a33 | 432 | #ifndef DISABLE_OCSP |
f5d78688 JH |
433 | void |
434 | x509_store_dump_cert_s_names(X509_STORE * store) | |
435 | { | |
436 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
f5d78688 JH |
437 | static uschar name[256]; |
438 | ||
d7978c0f | 439 | for (int i= 0; i < sk_X509_OBJECT_num(roots); i++) |
f5d78688 JH |
440 | { |
441 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
442 | if(tmp_obj->type == X509_LU_X509) | |
443 | { | |
70e384dd JH |
444 | X509_NAME * sn = X509_get_subject_name(tmp_obj->data.x509); |
445 | if (X509_NAME_oneline(sn, CS name, sizeof(name))) | |
446 | { | |
447 | name[sizeof(name)-1] = '\0'; | |
448 | debug_printf(" %s\n", name); | |
449 | } | |
f5d78688 JH |
450 | } |
451 | } | |
452 | } | |
453 | #endif | |
454 | */ | |
455 | ||
059ec3d9 | 456 | |
0cbf2b82 | 457 | #ifndef DISABLE_EVENT |
f69979cf JH |
458 | static int |
459 | verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn, | |
460 | BOOL *calledp, const BOOL *optionalp, const uschar * what) | |
461 | { | |
462 | uschar * ev; | |
463 | uschar * yield; | |
464 | X509 * old_cert; | |
465 | ||
466 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; | |
467 | if (ev) | |
468 | { | |
aaba7d03 | 469 | DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth); |
f69979cf JH |
470 | old_cert = tlsp->peercert; |
471 | tlsp->peercert = X509_dup(cert); | |
472 | /* NB we do not bother setting peerdn */ | |
473 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) | |
474 | { | |
475 | log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: " | |
476 | "depth=%d cert=%s: %s", | |
477 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
478 | what, depth, dn, yield); | |
479 | *calledp = TRUE; | |
480 | if (!*optionalp) | |
481 | { | |
482 | if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */ | |
483 | return 1; /* reject (leaving peercert set) */ | |
484 | } | |
485 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
486 | "(host in tls_try_verify_hosts)\n"); | |
487 | } | |
488 | X509_free(tlsp->peercert); | |
489 | tlsp->peercert = old_cert; | |
490 | } | |
491 | return 0; | |
492 | } | |
493 | #endif | |
494 | ||
059ec3d9 PH |
495 | /************************************************* |
496 | * Callback for verification * | |
497 | *************************************************/ | |
498 | ||
499 | /* The SSL library does certificate verification if set up to do so. This | |
500 | callback has the current yes/no state is in "state". If verification succeeded, | |
f69979cf JH |
501 | we set the certificate-verified flag. If verification failed, what happens |
502 | depends on whether the client is required to present a verifiable certificate | |
503 | or not. | |
059ec3d9 PH |
504 | |
505 | If verification is optional, we change the state to yes, but still log the | |
506 | verification error. For some reason (it really would help to have proper | |
507 | documentation of OpenSSL), this callback function then gets called again, this | |
f69979cf JH |
508 | time with state = 1. We must take care not to set the private verified flag on |
509 | the second time through. | |
059ec3d9 PH |
510 | |
511 | Note: this function is not called if the client fails to present a certificate | |
512 | when asked. We get here only if a certificate has been received. Handling of | |
513 | optional verification for this case is done when requesting SSL to verify, by | |
514 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
515 | ||
a7538db1 JH |
516 | May be called multiple times for different issues with a certificate, even |
517 | for a given "depth" in the certificate chain. | |
518 | ||
059ec3d9 | 519 | Arguments: |
f2f2c91b JH |
520 | preverify_ok current yes/no state as 1/0 |
521 | x509ctx certificate information. | |
522 | tlsp per-direction (client vs. server) support data | |
523 | calledp has-been-called flag | |
524 | optionalp verification-is-optional flag | |
059ec3d9 | 525 | |
f2f2c91b | 526 | Returns: 0 if verification should fail, otherwise 1 |
059ec3d9 PH |
527 | */ |
528 | ||
529 | static int | |
70e384dd JH |
530 | verify_callback(int preverify_ok, X509_STORE_CTX * x509ctx, |
531 | tls_support * tlsp, BOOL * calledp, BOOL * optionalp) | |
059ec3d9 | 532 | { |
421aff85 | 533 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 534 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 535 | uschar dn[256]; |
059ec3d9 | 536 | |
70e384dd JH |
537 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
538 | { | |
539 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
540 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
541 | tlsp == &tls_out ? deliver_host_address : sender_host_address); | |
542 | return 0; | |
543 | } | |
f69979cf | 544 | dn[sizeof(dn)-1] = '\0'; |
059ec3d9 | 545 | |
f2f2c91b | 546 | if (preverify_ok == 0) |
059ec3d9 | 547 | { |
f77197ae JH |
548 | uschar * extra = verify_mode ? string_sprintf(" (during %c-verify for [%s])", |
549 | *verify_mode, sender_host_address) | |
550 | : US""; | |
551 | log_write(0, LOG_MAIN, "[%s] SSL verify error%s: depth=%d error=%s cert=%s", | |
552 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
553 | extra, depth, | |
554 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), dn); | |
a2ff477a | 555 | *calledp = TRUE; |
9d1c15ef JH |
556 | if (!*optionalp) |
557 | { | |
f69979cf JH |
558 | if (!tlsp->peercert) |
559 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
560 | return 0; /* reject */ | |
9d1c15ef | 561 | } |
059ec3d9 PH |
562 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
563 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
564 | } |
565 | ||
a7538db1 | 566 | else if (depth != 0) |
059ec3d9 | 567 | { |
f69979cf | 568 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn); |
f2de3a33 | 569 | #ifndef DISABLE_OCSP |
f5d78688 JH |
570 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
571 | { /* client, wanting stapling */ | |
572 | /* Add the server cert's signing chain as the one | |
573 | for the verification of the OCSP stapled information. */ | |
94431adb | 574 | |
f5d78688 | 575 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, |
421aff85 | 576 | cert)) |
f5d78688 | 577 | ERR_clear_error(); |
c3033f13 | 578 | sk_X509_push(client_static_cbinfo->verify_stack, cert); |
f5d78688 | 579 | } |
a7538db1 | 580 | #endif |
0cbf2b82 | 581 | #ifndef DISABLE_EVENT |
f69979cf JH |
582 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
583 | return 0; /* reject, with peercert set */ | |
f5d78688 | 584 | #endif |
059ec3d9 PH |
585 | } |
586 | else | |
587 | { | |
55414b25 | 588 | const uschar * verify_cert_hostnames; |
e51c7be2 | 589 | |
e51c7be2 JH |
590 | if ( tlsp == &tls_out |
591 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
afdb5e9c | 592 | /* client, wanting hostname check */ |
e51c7be2 | 593 | { |
f69979cf | 594 | |
740f36d4 | 595 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
f69979cf JH |
596 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
597 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
598 | # endif | |
599 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
600 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
601 | # endif | |
e51c7be2 | 602 | int sep = 0; |
55414b25 | 603 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 604 | uschar * name; |
d8e7834a JH |
605 | int rc; |
606 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
f40d5be3 | 607 | if ((rc = X509_check_host(cert, CCS name, 0, |
8d692470 | 608 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
740f36d4 JH |
609 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS, |
610 | NULL))) | |
d8e7834a JH |
611 | { |
612 | if (rc < 0) | |
613 | { | |
93a6fce2 | 614 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
f77197ae | 615 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
616 | name = NULL; |
617 | } | |
e51c7be2 | 618 | break; |
d8e7834a | 619 | } |
e51c7be2 | 620 | if (!name) |
f69979cf | 621 | #else |
e51c7be2 | 622 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) |
f69979cf | 623 | #endif |
e51c7be2 | 624 | { |
f77197ae JH |
625 | uschar * extra = verify_mode |
626 | ? string_sprintf(" (during %c-verify for [%s])", | |
627 | *verify_mode, sender_host_address) | |
628 | : US""; | |
e51c7be2 | 629 | log_write(0, LOG_MAIN, |
f77197ae JH |
630 | "[%s] SSL verify error%s: certificate name mismatch: DN=\"%s\" H=\"%s\"", |
631 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
632 | extra, dn, verify_cert_hostnames); | |
a3ef7310 JH |
633 | *calledp = TRUE; |
634 | if (!*optionalp) | |
f69979cf JH |
635 | { |
636 | if (!tlsp->peercert) | |
637 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
638 | return 0; /* reject */ | |
639 | } | |
a3ef7310 JH |
640 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
641 | "tls_try_verify_hosts)\n"); | |
e51c7be2 | 642 | } |
f69979cf | 643 | } |
e51c7be2 | 644 | |
0cbf2b82 | 645 | #ifndef DISABLE_EVENT |
f69979cf JH |
646 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
647 | return 0; /* reject, with peercert set */ | |
e51c7be2 JH |
648 | #endif |
649 | ||
93dcb1c2 | 650 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
f69979cf | 651 | *calledp ? "" : " authenticated", dn); |
93dcb1c2 JH |
652 | if (!*calledp) tlsp->certificate_verified = TRUE; |
653 | *calledp = TRUE; | |
059ec3d9 PH |
654 | } |
655 | ||
a7538db1 | 656 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
657 | } |
658 | ||
a2ff477a | 659 | static int |
f2f2c91b | 660 | verify_callback_client(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 661 | { |
f2f2c91b JH |
662 | return verify_callback(preverify_ok, x509ctx, &tls_out, |
663 | &client_verify_callback_called, &client_verify_optional); | |
a2ff477a JH |
664 | } |
665 | ||
666 | static int | |
f2f2c91b | 667 | verify_callback_server(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 668 | { |
f2f2c91b JH |
669 | return verify_callback(preverify_ok, x509ctx, &tls_in, |
670 | &server_verify_callback_called, &server_verify_optional); | |
a2ff477a JH |
671 | } |
672 | ||
059ec3d9 | 673 | |
c0635b6d | 674 | #ifdef SUPPORT_DANE |
53a7196b | 675 | |
e5cccda9 JH |
676 | /* This gets called *by* the dane library verify callback, which interposes |
677 | itself. | |
678 | */ | |
679 | static int | |
f2f2c91b | 680 | verify_callback_client_dane(int preverify_ok, X509_STORE_CTX * x509ctx) |
e5cccda9 JH |
681 | { |
682 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
f69979cf | 683 | uschar dn[256]; |
83b27293 | 684 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
5c75db2e | 685 | #ifndef DISABLE_EVENT |
f69979cf | 686 | BOOL dummy_called, optional = FALSE; |
83b27293 | 687 | #endif |
e5cccda9 | 688 | |
70e384dd JH |
689 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
690 | { | |
691 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
692 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
693 | deliver_host_address); | |
694 | return 0; | |
695 | } | |
f69979cf | 696 | dn[sizeof(dn)-1] = '\0'; |
e5cccda9 | 697 | |
f2f2c91b JH |
698 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s depth %d %s\n", |
699 | preverify_ok ? "ok":"BAD", depth, dn); | |
e5cccda9 | 700 | |
0cbf2b82 | 701 | #ifndef DISABLE_EVENT |
f69979cf JH |
702 | if (verify_event(&tls_out, cert, depth, dn, |
703 | &dummy_called, &optional, US"DANE")) | |
704 | return 0; /* reject, with peercert set */ | |
83b27293 JH |
705 | #endif |
706 | ||
f2f2c91b | 707 | if (preverify_ok == 1) |
6fbf3599 JH |
708 | { |
709 | tls_out.dane_verified = tls_out.certificate_verified = TRUE; | |
710 | #ifndef DISABLE_OCSP | |
711 | if (client_static_cbinfo->u_ocsp.client.verify_store) | |
712 | { /* client, wanting stapling */ | |
713 | /* Add the server cert's signing chain as the one | |
714 | for the verification of the OCSP stapled information. */ | |
715 | ||
716 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
717 | cert)) | |
718 | ERR_clear_error(); | |
719 | sk_X509_push(client_static_cbinfo->verify_stack, cert); | |
720 | } | |
721 | #endif | |
722 | } | |
f2f2c91b JH |
723 | else |
724 | { | |
725 | int err = X509_STORE_CTX_get_error(x509ctx); | |
726 | DEBUG(D_tls) | |
727 | debug_printf(" - err %d '%s'\n", err, X509_verify_cert_error_string(err)); | |
3c51463e | 728 | if (err == X509_V_ERR_APPLICATION_VERIFICATION) |
f2f2c91b JH |
729 | preverify_ok = 1; |
730 | } | |
731 | return preverify_ok; | |
e5cccda9 | 732 | } |
53a7196b | 733 | |
c0635b6d | 734 | #endif /*SUPPORT_DANE*/ |
e5cccda9 | 735 | |
059ec3d9 PH |
736 | |
737 | /************************************************* | |
738 | * Information callback * | |
739 | *************************************************/ | |
740 | ||
741 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
742 | are doing. We copy the string to the debugging output when TLS debugging has |
743 | been requested. | |
059ec3d9 PH |
744 | |
745 | Arguments: | |
746 | s the SSL connection | |
747 | where | |
748 | ret | |
749 | ||
750 | Returns: nothing | |
751 | */ | |
752 | ||
753 | static void | |
754 | info_callback(SSL *s, int where, int ret) | |
755 | { | |
0abc5a13 JH |
756 | DEBUG(D_tls) |
757 | { | |
758 | const uschar * str; | |
759 | ||
760 | if (where & SSL_ST_CONNECT) | |
48224640 | 761 | str = US"SSL_connect"; |
0abc5a13 | 762 | else if (where & SSL_ST_ACCEPT) |
48224640 | 763 | str = US"SSL_accept"; |
0abc5a13 | 764 | else |
48224640 | 765 | str = US"SSL info (undefined)"; |
0abc5a13 JH |
766 | |
767 | if (where & SSL_CB_LOOP) | |
768 | debug_printf("%s: %s\n", str, SSL_state_string_long(s)); | |
769 | else if (where & SSL_CB_ALERT) | |
770 | debug_printf("SSL3 alert %s:%s:%s\n", | |
48224640 | 771 | str = where & SSL_CB_READ ? US"read" : US"write", |
0abc5a13 JH |
772 | SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret)); |
773 | else if (where & SSL_CB_EXIT) | |
774 | if (ret == 0) | |
775 | debug_printf("%s: failed in %s\n", str, SSL_state_string_long(s)); | |
776 | else if (ret < 0) | |
777 | debug_printf("%s: error in %s\n", str, SSL_state_string_long(s)); | |
778 | else if (where & SSL_CB_HANDSHAKE_START) | |
779 | debug_printf("%s: hshake start: %s\n", str, SSL_state_string_long(s)); | |
780 | else if (where & SSL_CB_HANDSHAKE_DONE) | |
781 | debug_printf("%s: hshake done: %s\n", str, SSL_state_string_long(s)); | |
782 | } | |
059ec3d9 PH |
783 | } |
784 | ||
8a40db1c JH |
785 | static void |
786 | keylog_callback(const SSL *ssl, const char *line) | |
787 | { | |
788 | DEBUG(D_tls) debug_printf("%.200s\n", line); | |
789 | } | |
790 | ||
059ec3d9 PH |
791 | |
792 | ||
793 | /************************************************* | |
794 | * Initialize for DH * | |
795 | *************************************************/ | |
796 | ||
797 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
798 | ||
799 | Arguments: | |
038597d2 | 800 | sctx The current SSL CTX (inbound or outbound) |
a799883d | 801 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 802 | host connected host, if client; NULL if server |
cf0c6164 | 803 | errstr error string pointer |
059ec3d9 PH |
804 | |
805 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
806 | */ | |
807 | ||
808 | static BOOL | |
cf0c6164 | 809 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr) |
059ec3d9 | 810 | { |
059ec3d9 PH |
811 | BIO *bio; |
812 | DH *dh; | |
813 | uschar *dhexpanded; | |
a799883d | 814 | const char *pem; |
6600985a | 815 | int dh_bitsize; |
059ec3d9 | 816 | |
cf0c6164 | 817 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr)) |
059ec3d9 PH |
818 | return FALSE; |
819 | ||
0df4ab80 | 820 | if (!dhexpanded || !*dhexpanded) |
a799883d | 821 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 822 | else if (dhexpanded[0] == '/') |
059ec3d9 | 823 | { |
0df4ab80 | 824 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 825 | { |
7199e1ee | 826 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
cf0c6164 | 827 | host, US strerror(errno), errstr); |
a799883d | 828 | return FALSE; |
059ec3d9 | 829 | } |
a799883d PP |
830 | } |
831 | else | |
832 | { | |
833 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 834 | { |
a799883d PP |
835 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
836 | return TRUE; | |
059ec3d9 | 837 | } |
a799883d | 838 | |
0df4ab80 | 839 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
840 | { |
841 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
cf0c6164 | 842 | host, US strerror(errno), errstr); |
a799883d PP |
843 | return FALSE; |
844 | } | |
845 | bio = BIO_new_mem_buf(CS pem, -1); | |
846 | } | |
847 | ||
0df4ab80 | 848 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 849 | { |
059ec3d9 | 850 | BIO_free(bio); |
a799883d | 851 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
cf0c6164 | 852 | host, NULL, errstr); |
a799883d PP |
853 | return FALSE; |
854 | } | |
855 | ||
6600985a PP |
856 | /* note: our default limit of 2236 is not a multiple of 8; the limit comes from |
857 | * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with | |
858 | * 2236. But older OpenSSL can only report in bytes (octets), not bits. | |
859 | * If someone wants to dance at the edge, then they can raise the limit or use | |
860 | * current libraries. */ | |
861 | #ifdef EXIM_HAVE_OPENSSL_DH_BITS | |
862 | /* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022 | |
863 | * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */ | |
864 | dh_bitsize = DH_bits(dh); | |
865 | #else | |
866 | dh_bitsize = 8 * DH_size(dh); | |
867 | #endif | |
868 | ||
a799883d PP |
869 | /* Even if it is larger, we silently return success rather than cause things |
870 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
871 | * debatable choice. */ | |
6600985a | 872 | if (dh_bitsize > tls_dh_max_bits) |
a799883d PP |
873 | { |
874 | DEBUG(D_tls) | |
170f4904 | 875 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n", |
6600985a | 876 | dh_bitsize, tls_dh_max_bits); |
a799883d PP |
877 | } |
878 | else | |
879 | { | |
880 | SSL_CTX_set_tmp_dh(sctx, dh); | |
881 | DEBUG(D_tls) | |
882 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
6600985a | 883 | dhexpanded ? dhexpanded : US"default", dh_bitsize); |
059ec3d9 PH |
884 | } |
885 | ||
a799883d PP |
886 | DH_free(dh); |
887 | BIO_free(bio); | |
888 | ||
889 | return TRUE; | |
059ec3d9 PH |
890 | } |
891 | ||
892 | ||
893 | ||
894 | ||
038597d2 PP |
895 | /************************************************* |
896 | * Initialize for ECDH * | |
897 | *************************************************/ | |
898 | ||
899 | /* Load parameters for ECDH encryption. | |
900 | ||
901 | For now, we stick to NIST P-256 because: it's simple and easy to configure; | |
902 | it avoids any patent issues that might bite redistributors; despite events in | |
903 | the news and concerns over curve choices, we're not cryptographers, we're not | |
904 | pretending to be, and this is "good enough" to be better than no support, | |
905 | protecting against most adversaries. Given another year or two, there might | |
906 | be sufficient clarity about a "right" way forward to let us make an informed | |
907 | decision, instead of a knee-jerk reaction. | |
908 | ||
909 | Longer-term, we should look at supporting both various named curves and | |
910 | external files generated with "openssl ecparam", much as we do for init_dh(). | |
911 | We should also support "none" as a value, to explicitly avoid initialisation. | |
912 | ||
913 | Patches welcome. | |
914 | ||
915 | Arguments: | |
916 | sctx The current SSL CTX (inbound or outbound) | |
917 | host connected host, if client; NULL if server | |
cf0c6164 | 918 | errstr error string pointer |
038597d2 PP |
919 | |
920 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
921 | */ | |
922 | ||
923 | static BOOL | |
cf0c6164 | 924 | init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr) |
038597d2 | 925 | { |
63f0dbe0 JH |
926 | #ifdef OPENSSL_NO_ECDH |
927 | return TRUE; | |
928 | #else | |
929 | ||
10ca4f1c JH |
930 | EC_KEY * ecdh; |
931 | uschar * exp_curve; | |
932 | int nid; | |
933 | BOOL rv; | |
934 | ||
038597d2 PP |
935 | if (host) /* No ECDH setup for clients, only for servers */ |
936 | return TRUE; | |
937 | ||
10ca4f1c | 938 | # ifndef EXIM_HAVE_ECDH |
038597d2 PP |
939 | DEBUG(D_tls) |
940 | debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); | |
941 | return TRUE; | |
038597d2 | 942 | # else |
10ca4f1c | 943 | |
cf0c6164 | 944 | if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr)) |
10ca4f1c JH |
945 | return FALSE; |
946 | if (!exp_curve || !*exp_curve) | |
947 | return TRUE; | |
948 | ||
8e53a4fc | 949 | /* "auto" needs to be handled carefully. |
4c04137d | 950 | * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1 |
8e53a4fc | 951 | * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto |
4c04137d | 952 | * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO) |
8e53a4fc HSHR |
953 | * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection |
954 | * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b | |
955 | */ | |
10ca4f1c | 956 | if (Ustrcmp(exp_curve, "auto") == 0) |
038597d2 | 957 | { |
8e53a4fc | 958 | #if OPENSSL_VERSION_NUMBER < 0x10002000L |
10ca4f1c | 959 | DEBUG(D_tls) debug_printf( |
8e53a4fc | 960 | "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n"); |
78a3bbd5 | 961 | exp_curve = US"prime256v1"; |
8e53a4fc HSHR |
962 | #else |
963 | # if defined SSL_CTRL_SET_ECDH_AUTO | |
964 | DEBUG(D_tls) debug_printf( | |
965 | "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n"); | |
10ca4f1c JH |
966 | SSL_CTX_set_ecdh_auto(sctx, 1); |
967 | return TRUE; | |
8e53a4fc HSHR |
968 | # else |
969 | DEBUG(D_tls) debug_printf( | |
970 | "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n"); | |
971 | return TRUE; | |
972 | # endif | |
973 | #endif | |
10ca4f1c | 974 | } |
038597d2 | 975 | |
10ca4f1c JH |
976 | DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve); |
977 | if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef | |
978 | # ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID | |
979 | && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef | |
980 | # endif | |
981 | ) | |
982 | { | |
cf0c6164 JH |
983 | tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve), |
984 | host, NULL, errstr); | |
10ca4f1c JH |
985 | return FALSE; |
986 | } | |
038597d2 | 987 | |
10ca4f1c JH |
988 | if (!(ecdh = EC_KEY_new_by_curve_name(nid))) |
989 | { | |
cf0c6164 | 990 | tls_error(US"Unable to create ec curve", host, NULL, errstr); |
10ca4f1c | 991 | return FALSE; |
038597d2 | 992 | } |
10ca4f1c JH |
993 | |
994 | /* The "tmp" in the name here refers to setting a temporary key | |
995 | not to the stability of the interface. */ | |
996 | ||
997 | if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) | |
cf0c6164 | 998 | tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr); |
10ca4f1c JH |
999 | else |
1000 | DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); | |
1001 | ||
1002 | EC_KEY_free(ecdh); | |
1003 | return !rv; | |
1004 | ||
1005 | # endif /*EXIM_HAVE_ECDH*/ | |
1006 | #endif /*OPENSSL_NO_ECDH*/ | |
038597d2 PP |
1007 | } |
1008 | ||
1009 | ||
1010 | ||
1011 | ||
f2de3a33 | 1012 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1013 | /************************************************* |
1014 | * Load OCSP information into state * | |
1015 | *************************************************/ | |
f5d78688 | 1016 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
1017 | caller has determined this is needed. Checks validity. Debugs a message |
1018 | if invalid. | |
1019 | ||
1020 | ASSUMES: single response, for single cert. | |
1021 | ||
1022 | Arguments: | |
1023 | sctx the SSL_CTX* to update | |
1024 | cbinfo various parts of session state | |
1025 | expanded the filename putatively holding an OCSP response | |
1026 | ||
1027 | */ | |
1028 | ||
1029 | static void | |
f5d78688 | 1030 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 | 1031 | { |
ee5b1e28 JH |
1032 | BIO * bio; |
1033 | OCSP_RESPONSE * resp; | |
1034 | OCSP_BASICRESP * basic_response; | |
1035 | OCSP_SINGLERESP * single_response; | |
1036 | ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd; | |
ee5b1e28 | 1037 | STACK_OF(X509) * sk; |
3f7eeb86 PP |
1038 | unsigned long verify_flags; |
1039 | int status, reason, i; | |
1040 | ||
f5d78688 JH |
1041 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
1042 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 1043 | { |
f5d78688 JH |
1044 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
1045 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
1046 | } |
1047 | ||
ee5b1e28 | 1048 | if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"))) |
3f7eeb86 PP |
1049 | { |
1050 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 1051 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
1052 | return; |
1053 | } | |
1054 | ||
1055 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
1056 | BIO_free(bio); | |
1057 | if (!resp) | |
1058 | { | |
1059 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
1060 | return; | |
1061 | } | |
1062 | ||
ee5b1e28 | 1063 | if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL) |
3f7eeb86 PP |
1064 | { |
1065 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
1066 | OCSP_response_status_str(status), status); | |
f5d78688 | 1067 | goto bad; |
3f7eeb86 PP |
1068 | } |
1069 | ||
ee5b1e28 | 1070 | if (!(basic_response = OCSP_response_get1_basic(resp))) |
3f7eeb86 PP |
1071 | { |
1072 | DEBUG(D_tls) | |
1073 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 1074 | goto bad; |
3f7eeb86 PP |
1075 | } |
1076 | ||
c3033f13 | 1077 | sk = cbinfo->verify_stack; |
3f7eeb86 PP |
1078 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ |
1079 | ||
1080 | /* May need to expose ability to adjust those flags? | |
1081 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
1082 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
1083 | ||
4c04137d | 1084 | /* This does a full verify on the OCSP proof before we load it for serving |
ee5b1e28 JH |
1085 | up; possibly overkill - just date-checks might be nice enough. |
1086 | ||
1087 | OCSP_basic_verify takes a "store" arg, but does not | |
1088 | use it for the chain verification, which is all we do | |
1089 | when OCSP_NOVERIFY is set. The content from the wire | |
1090 | "basic_response" and a cert-stack "sk" are all that is used. | |
1091 | ||
c3033f13 JH |
1092 | We have a stack, loaded in setup_certs() if tls_verify_certificates |
1093 | was a file (not a directory, or "system"). It is unfortunate we | |
1094 | cannot used the connection context store, as that would neatly | |
1095 | handle the "system" case too, but there seems to be no library | |
1096 | function for getting a stack from a store. | |
e3555426 | 1097 | [ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ] |
c3033f13 JH |
1098 | We do not free the stack since it could be needed a second time for |
1099 | SNI handling. | |
1100 | ||
4c04137d | 1101 | Separately we might try to replace using OCSP_basic_verify() - which seems to not |
5ec37a55 | 1102 | be a public interface into the OpenSSL library (there's no manual entry) - |
ee5b1e28 | 1103 | But what with? We also use OCSP_basic_verify in the client stapling callback. |
4c04137d | 1104 | And there we NEED it; we must verify that status... unless the |
ee5b1e28 JH |
1105 | library does it for us anyway? */ |
1106 | ||
1107 | if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0) | |
3f7eeb86 | 1108 | { |
ee5b1e28 JH |
1109 | DEBUG(D_tls) |
1110 | { | |
0abc5a13 | 1111 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3f7eeb86 | 1112 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); |
f5d78688 JH |
1113 | } |
1114 | goto bad; | |
3f7eeb86 PP |
1115 | } |
1116 | ||
1117 | /* Here's the simplifying assumption: there's only one response, for the | |
1118 | one certificate we use, and nothing for anything else in a chain. If this | |
1119 | proves false, we need to extract a cert id from our issued cert | |
1120 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
1121 | right cert in the stack and then calls OCSP_single_get0_status()). | |
1122 | ||
1123 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
ee5b1e28 JH |
1124 | |
1125 | if (!(single_response = OCSP_resp_get0(basic_response, 0))) | |
3f7eeb86 PP |
1126 | { |
1127 | DEBUG(D_tls) | |
1128 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 1129 | goto bad; |
3f7eeb86 PP |
1130 | } |
1131 | ||
1132 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 1133 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 1134 | { |
f5d78688 JH |
1135 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
1136 | OCSP_cert_status_str(status), status, | |
1137 | OCSP_crl_reason_str(reason), reason); | |
1138 | goto bad; | |
3f7eeb86 PP |
1139 | } |
1140 | ||
1141 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
1142 | { | |
1143 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 1144 | goto bad; |
3f7eeb86 PP |
1145 | } |
1146 | ||
f5d78688 | 1147 | supply_response: |
47195144 | 1148 | cbinfo->u_ocsp.server.response = resp; /*XXX stack?*/ |
f5d78688 JH |
1149 | return; |
1150 | ||
1151 | bad: | |
8768d548 | 1152 | if (f.running_in_test_harness) |
018058b2 JH |
1153 | { |
1154 | extern char ** environ; | |
d7978c0f | 1155 | if (environ) for (uschar ** p = USS environ; *p; p++) |
018058b2 JH |
1156 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) |
1157 | { | |
1158 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
1159 | goto supply_response; | |
1160 | } | |
1161 | } | |
f5d78688 | 1162 | return; |
3f7eeb86 | 1163 | } |
f2de3a33 | 1164 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1165 | |
1166 | ||
1167 | ||
1168 | ||
23bb6982 JH |
1169 | /* Create and install a selfsigned certificate, for use in server mode */ |
1170 | ||
1171 | static int | |
cf0c6164 | 1172 | tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr) |
23bb6982 JH |
1173 | { |
1174 | X509 * x509 = NULL; | |
1175 | EVP_PKEY * pkey; | |
1176 | RSA * rsa; | |
1177 | X509_NAME * name; | |
1178 | uschar * where; | |
1179 | ||
1180 | where = US"allocating pkey"; | |
1181 | if (!(pkey = EVP_PKEY_new())) | |
1182 | goto err; | |
1183 | ||
1184 | where = US"allocating cert"; | |
1185 | if (!(x509 = X509_new())) | |
1186 | goto err; | |
1187 | ||
1188 | where = US"generating pkey"; | |
6aac3239 | 1189 | if (!(rsa = rsa_callback(NULL, 0, 2048))) |
23bb6982 JH |
1190 | goto err; |
1191 | ||
4c04137d | 1192 | where = US"assigning pkey"; |
23bb6982 JH |
1193 | if (!EVP_PKEY_assign_RSA(pkey, rsa)) |
1194 | goto err; | |
1195 | ||
1196 | X509_set_version(x509, 2); /* N+1 - version 3 */ | |
1613fd68 | 1197 | ASN1_INTEGER_set(X509_get_serialNumber(x509), 1); |
23bb6982 JH |
1198 | X509_gmtime_adj(X509_get_notBefore(x509), 0); |
1199 | X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60); /* 1 hour */ | |
1200 | X509_set_pubkey(x509, pkey); | |
1201 | ||
1202 | name = X509_get_subject_name(x509); | |
1203 | X509_NAME_add_entry_by_txt(name, "C", | |
4dc2379a | 1204 | MBSTRING_ASC, CUS "UK", -1, -1, 0); |
23bb6982 | 1205 | X509_NAME_add_entry_by_txt(name, "O", |
4dc2379a | 1206 | MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0); |
23bb6982 | 1207 | X509_NAME_add_entry_by_txt(name, "CN", |
4dc2379a | 1208 | MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0); |
23bb6982 JH |
1209 | X509_set_issuer_name(x509, name); |
1210 | ||
1211 | where = US"signing cert"; | |
1212 | if (!X509_sign(x509, pkey, EVP_md5())) | |
1213 | goto err; | |
1214 | ||
1215 | where = US"installing selfsign cert"; | |
1216 | if (!SSL_CTX_use_certificate(sctx, x509)) | |
1217 | goto err; | |
1218 | ||
1219 | where = US"installing selfsign key"; | |
1220 | if (!SSL_CTX_use_PrivateKey(sctx, pkey)) | |
1221 | goto err; | |
1222 | ||
1223 | return OK; | |
1224 | ||
1225 | err: | |
cf0c6164 | 1226 | (void) tls_error(where, NULL, NULL, errstr); |
23bb6982 JH |
1227 | if (x509) X509_free(x509); |
1228 | if (pkey) EVP_PKEY_free(pkey); | |
1229 | return DEFER; | |
1230 | } | |
1231 | ||
1232 | ||
1233 | ||
1234 | ||
ba86e143 JH |
1235 | static int |
1236 | tls_add_certfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1237 | uschar ** errstr) | |
1238 | { | |
1239 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", file); | |
1240 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS file)) | |
1241 | return tls_error(string_sprintf( | |
1242 | "SSL_CTX_use_certificate_chain_file file=%s", file), | |
1243 | cbinfo->host, NULL, errstr); | |
1244 | return 0; | |
1245 | } | |
1246 | ||
1247 | static int | |
1248 | tls_add_pkeyfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1249 | uschar ** errstr) | |
1250 | { | |
1251 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", file); | |
1252 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS file, SSL_FILETYPE_PEM)) | |
1253 | return tls_error(string_sprintf( | |
1254 | "SSL_CTX_use_PrivateKey_file file=%s", file), cbinfo->host, NULL, errstr); | |
1255 | return 0; | |
1256 | } | |
1257 | ||
1258 | ||
7be682ca PP |
1259 | /************************************************* |
1260 | * Expand key and cert file specs * | |
1261 | *************************************************/ | |
1262 | ||
f5d78688 | 1263 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
1264 | new context, if Server Name Indication was used and tls_sni was seen in |
1265 | the certificate string. | |
1266 | ||
1267 | Arguments: | |
1268 | sctx the SSL_CTX* to update | |
1269 | cbinfo various parts of session state | |
cf0c6164 | 1270 | errstr error string pointer |
7be682ca PP |
1271 | |
1272 | Returns: OK/DEFER/FAIL | |
1273 | */ | |
1274 | ||
1275 | static int | |
cf0c6164 JH |
1276 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, |
1277 | uschar ** errstr) | |
7be682ca PP |
1278 | { |
1279 | uschar *expanded; | |
1280 | ||
23bb6982 | 1281 | if (!cbinfo->certificate) |
7be682ca | 1282 | { |
ba86e143 | 1283 | if (!cbinfo->is_server) /* client */ |
23bb6982 | 1284 | return OK; |
afdb5e9c | 1285 | /* server */ |
cf0c6164 | 1286 | if (tls_install_selfsign(sctx, errstr) != OK) |
23bb6982 | 1287 | return DEFER; |
7be682ca | 1288 | } |
23bb6982 JH |
1289 | else |
1290 | { | |
ba86e143 JH |
1291 | int err; |
1292 | ||
23bb6982 JH |
1293 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
1294 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
1295 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
1296 | ) | |
1297 | reexpand_tls_files_for_sni = TRUE; | |
7be682ca | 1298 | |
cf0c6164 | 1299 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr)) |
23bb6982 JH |
1300 | return DEFER; |
1301 | ||
ba86e143 JH |
1302 | if (expanded) |
1303 | if (cbinfo->is_server) | |
1304 | { | |
1305 | const uschar * file_list = expanded; | |
1306 | int sep = 0; | |
1307 | uschar * file; | |
1308 | ||
1309 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1310 | if ((err = tls_add_certfile(sctx, cbinfo, file, errstr))) | |
1311 | return err; | |
1312 | } | |
1313 | else /* would there ever be a need for multiple client certs? */ | |
1314 | if ((err = tls_add_certfile(sctx, cbinfo, expanded, errstr))) | |
1315 | return err; | |
7be682ca | 1316 | |
5a2a0989 JH |
1317 | if ( cbinfo->privatekey |
1318 | && !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr)) | |
23bb6982 | 1319 | return DEFER; |
7be682ca | 1320 | |
23bb6982 JH |
1321 | /* If expansion was forced to fail, key_expanded will be NULL. If the result |
1322 | of the expansion is an empty string, ignore it also, and assume the private | |
1323 | key is in the same file as the certificate. */ | |
1324 | ||
1325 | if (expanded && *expanded) | |
ba86e143 JH |
1326 | if (cbinfo->is_server) |
1327 | { | |
1328 | const uschar * file_list = expanded; | |
1329 | int sep = 0; | |
1330 | uschar * file; | |
1331 | ||
1332 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1333 | if ((err = tls_add_pkeyfile(sctx, cbinfo, file, errstr))) | |
1334 | return err; | |
1335 | } | |
1336 | else /* would there ever be a need for multiple client certs? */ | |
1337 | if ((err = tls_add_pkeyfile(sctx, cbinfo, expanded, errstr))) | |
1338 | return err; | |
7be682ca PP |
1339 | } |
1340 | ||
f2de3a33 | 1341 | #ifndef DISABLE_OCSP |
f40d5be3 | 1342 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1343 | { |
47195144 | 1344 | /*XXX stack*/ |
cf0c6164 | 1345 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr)) |
3f7eeb86 PP |
1346 | return DEFER; |
1347 | ||
f40d5be3 | 1348 | if (expanded && *expanded) |
3f7eeb86 PP |
1349 | { |
1350 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f40d5be3 JH |
1351 | if ( cbinfo->u_ocsp.server.file_expanded |
1352 | && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 | 1353 | { |
f40d5be3 JH |
1354 | DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n"); |
1355 | } | |
1356 | else | |
f40d5be3 | 1357 | ocsp_load_response(sctx, cbinfo, expanded); |
3f7eeb86 PP |
1358 | } |
1359 | } | |
1360 | #endif | |
1361 | ||
7be682ca PP |
1362 | return OK; |
1363 | } | |
1364 | ||
1365 | ||
1366 | ||
1367 | ||
1368 | /************************************************* | |
1369 | * Callback to handle SNI * | |
1370 | *************************************************/ | |
1371 | ||
1372 | /* Called when acting as server during the TLS session setup if a Server Name | |
1373 | Indication extension was sent by the client. | |
1374 | ||
1375 | API documentation is OpenSSL s_server.c implementation. | |
1376 | ||
1377 | Arguments: | |
1378 | s SSL* of the current session | |
1379 | ad unknown (part of OpenSSL API) (unused) | |
1380 | arg Callback of "our" registered data | |
1381 | ||
1382 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
1383 | */ | |
1384 | ||
3bcbbbe2 | 1385 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
1386 | static int |
1387 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
1388 | { | |
1389 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 1390 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 1391 | int rc; |
3f0945ff | 1392 | int old_pool = store_pool; |
cf0c6164 | 1393 | uschar * dummy_errstr; |
7be682ca PP |
1394 | |
1395 | if (!servername) | |
1396 | return SSL_TLSEXT_ERR_OK; | |
1397 | ||
3f0945ff | 1398 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
1399 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
1400 | ||
1401 | /* Make the extension value available for expansion */ | |
3f0945ff | 1402 | store_pool = POOL_PERM; |
817d9f57 | 1403 | tls_in.sni = string_copy(US servername); |
3f0945ff | 1404 | store_pool = old_pool; |
7be682ca PP |
1405 | |
1406 | if (!reexpand_tls_files_for_sni) | |
1407 | return SSL_TLSEXT_ERR_OK; | |
1408 | ||
1409 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
1410 | not confident that memcpy wouldn't break some internal reference counting. | |
1411 | Especially since there's a references struct member, which would be off. */ | |
1412 | ||
7a8b9519 JH |
1413 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1414 | if (!(server_sni = SSL_CTX_new(TLS_server_method()))) | |
1415 | #else | |
0df4ab80 | 1416 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7a8b9519 | 1417 | #endif |
7be682ca | 1418 | { |
0abc5a13 | 1419 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
7be682ca | 1420 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); |
5a2a0989 | 1421 | goto bad; |
7be682ca PP |
1422 | } |
1423 | ||
1424 | /* Not sure how many of these are actually needed, since SSL object | |
1425 | already exists. Might even need this selfsame callback, for reneg? */ | |
1426 | ||
817d9f57 JH |
1427 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
1428 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
1429 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
1430 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
1431 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
1432 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
038597d2 | 1433 | |
cf0c6164 JH |
1434 | if ( !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr) |
1435 | || !init_ecdh(server_sni, NULL, &dummy_errstr) | |
038597d2 | 1436 | ) |
5a2a0989 | 1437 | goto bad; |
038597d2 | 1438 | |
ca954d7f JH |
1439 | if ( cbinfo->server_cipher_list |
1440 | && !SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list)) | |
5a2a0989 | 1441 | goto bad; |
ca954d7f | 1442 | |
f2de3a33 | 1443 | #ifndef DISABLE_OCSP |
f5d78688 | 1444 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1445 | { |
f5d78688 | 1446 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 1447 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
1448 | } |
1449 | #endif | |
7be682ca | 1450 | |
c3033f13 | 1451 | if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, |
cf0c6164 | 1452 | verify_callback_server, &dummy_errstr)) != OK) |
5a2a0989 | 1453 | goto bad; |
7be682ca | 1454 | |
3f7eeb86 PP |
1455 | /* do this after setup_certs, because this can require the certs for verifying |
1456 | OCSP information. */ | |
cf0c6164 | 1457 | if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK) |
5a2a0989 | 1458 | goto bad; |
a799883d | 1459 | |
7be682ca | 1460 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 1461 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca | 1462 | return SSL_TLSEXT_ERR_OK; |
5a2a0989 JH |
1463 | |
1464 | bad: return SSL_TLSEXT_ERR_ALERT_FATAL; | |
7be682ca | 1465 | } |
3bcbbbe2 | 1466 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
1467 | |
1468 | ||
1469 | ||
1470 | ||
f2de3a33 | 1471 | #ifndef DISABLE_OCSP |
f5d78688 | 1472 | |
3f7eeb86 PP |
1473 | /************************************************* |
1474 | * Callback to handle OCSP Stapling * | |
1475 | *************************************************/ | |
1476 | ||
1477 | /* Called when acting as server during the TLS session setup if the client | |
1478 | requests OCSP information with a Certificate Status Request. | |
1479 | ||
1480 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
1481 | project. | |
1482 | ||
1483 | */ | |
1484 | ||
1485 | static int | |
f5d78688 | 1486 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
1487 | { |
1488 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
47195144 | 1489 | uschar *response_der; /*XXX blob */ |
3f7eeb86 PP |
1490 | int response_der_len; |
1491 | ||
47195144 JH |
1492 | /*XXX stack: use SSL_get_certificate() to see which cert; from that work |
1493 | out which ocsp blob to send. Unfortunately, SSL_get_certificate is known | |
1494 | buggy in current OpenSSL; it returns the last cert loaded always rather than | |
1495 | the one actually presented. So we can't support a stack of OCSP proofs at | |
1496 | this time. */ | |
1497 | ||
af4a1bca | 1498 | DEBUG(D_tls) |
b3ef41c9 | 1499 | debug_printf("Received TLS status request (OCSP stapling); %s response\n", |
f5d78688 JH |
1500 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
1501 | ||
44662487 | 1502 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 1503 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
1504 | return SSL_TLSEXT_ERR_NOACK; |
1505 | ||
1506 | response_der = NULL; | |
47195144 | 1507 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, /*XXX stack*/ |
44662487 | 1508 | &response_der); |
3f7eeb86 PP |
1509 | if (response_der_len <= 0) |
1510 | return SSL_TLSEXT_ERR_NOACK; | |
1511 | ||
5e55c7a9 | 1512 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 1513 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
1514 | return SSL_TLSEXT_ERR_OK; |
1515 | } | |
1516 | ||
3f7eeb86 | 1517 | |
f5d78688 JH |
1518 | static void |
1519 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
1520 | { | |
1521 | BIO_printf(bp, "\t%s: ", str); | |
1522 | ASN1_GENERALIZEDTIME_print(bp, time); | |
1523 | BIO_puts(bp, "\n"); | |
1524 | } | |
1525 | ||
1526 | static int | |
1527 | tls_client_stapling_cb(SSL *s, void *arg) | |
1528 | { | |
1529 | tls_ext_ctx_cb * cbinfo = arg; | |
1530 | const unsigned char * p; | |
1531 | int len; | |
1532 | OCSP_RESPONSE * rsp; | |
1533 | OCSP_BASICRESP * bs; | |
1534 | int i; | |
1535 | ||
1536 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
1537 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
1538 | if(!p) | |
1539 | { | |
44662487 | 1540 | /* Expect this when we requested ocsp but got none */ |
6c6d6e48 | 1541 | if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher)) |
44662487 | 1542 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); |
f5d78688 JH |
1543 | else |
1544 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1545 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1546 | } |
018058b2 | 1547 | |
f5d78688 JH |
1548 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
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, parse error"); |
f5d78688 JH |
1553 | else |
1554 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1555 | return 0; | |
1556 | } | |
1557 | ||
1558 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
1559 | { | |
018058b2 | 1560 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1561 | if (LOGGING(tls_cipher)) |
1eca31ca | 1562 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1563 | else |
1564 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1565 | OCSP_RESPONSE_free(rsp); | |
1566 | return 0; | |
1567 | } | |
1568 | ||
1569 | /* We'd check the nonce here if we'd put one in the request. */ | |
1570 | /* However that would defeat cacheability on the server so we don't. */ | |
1571 | ||
f5d78688 JH |
1572 | /* This section of code reworked from OpenSSL apps source; |
1573 | The OpenSSL Project retains copyright: | |
1574 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1575 | */ | |
1576 | { | |
1577 | BIO * bp = NULL; | |
f5d78688 JH |
1578 | int status, reason; |
1579 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1580 | ||
57887ecc | 1581 | DEBUG(D_tls) bp = BIO_new_fp(debug_file, BIO_NOCLOSE); |
f5d78688 JH |
1582 | |
1583 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1584 | ||
1585 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1586 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1587 | ||
c3033f13 | 1588 | if ((i = OCSP_basic_verify(bs, cbinfo->verify_stack, |
44662487 | 1589 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) |
f5d78688 | 1590 | { |
018058b2 | 1591 | tls_out.ocsp = OCSP_FAILED; |
57887ecc JH |
1592 | if (LOGGING(tls_cipher)) log_write(0, LOG_MAIN, |
1593 | "Received TLS cert status response, itself unverifiable: %s", | |
1594 | ERR_reason_error_string(ERR_peek_error())); | |
f5d78688 JH |
1595 | BIO_printf(bp, "OCSP response verify failure\n"); |
1596 | ERR_print_errors(bp); | |
57887ecc | 1597 | OCSP_RESPONSE_print(bp, rsp, 0); |
c8dfb21d | 1598 | goto failed; |
f5d78688 JH |
1599 | } |
1600 | ||
1601 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1602 | ||
c8dfb21d JH |
1603 | /*XXX So we have a good stapled OCSP status. How do we know |
1604 | it is for the cert of interest? OpenSSL 1.1.0 has a routine | |
1605 | OCSP_resp_find_status() which matches on a cert id, which presumably | |
1606 | we should use. Making an id needs OCSP_cert_id_new(), which takes | |
1607 | issuerName, issuerKey, serialNumber. Are they all in the cert? | |
1608 | ||
1609 | For now, carry on blindly accepting the resp. */ | |
1610 | ||
f5d78688 | 1611 | { |
f5d78688 JH |
1612 | OCSP_SINGLERESP * single; |
1613 | ||
c8dfb21d JH |
1614 | #ifdef EXIM_HAVE_OCSP_RESP_COUNT |
1615 | if (OCSP_resp_count(bs) != 1) | |
1616 | #else | |
1617 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
f5d78688 | 1618 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) |
c8dfb21d | 1619 | #endif |
f5d78688 | 1620 | { |
018058b2 | 1621 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1622 | log_write(0, LOG_MAIN, "OCSP stapling " |
1623 | "with multiple responses not handled"); | |
c8dfb21d | 1624 | goto failed; |
f5d78688 JH |
1625 | } |
1626 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1627 | status = OCSP_single_get0_status(single, &reason, &rev, |
1628 | &thisupd, &nextupd); | |
f5d78688 JH |
1629 | } |
1630 | ||
f5d78688 JH |
1631 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1632 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1633 | if (!OCSP_check_validity(thisupd, nextupd, |
1634 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1635 | { |
018058b2 | 1636 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1637 | DEBUG(D_tls) ERR_print_errors(bp); |
1638 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
f5d78688 | 1639 | } |
44662487 | 1640 | else |
f5d78688 | 1641 | { |
44662487 JH |
1642 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1643 | OCSP_cert_status_str(status)); | |
1644 | switch(status) | |
1645 | { | |
1646 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1647 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1648 | i = 1; |
c8dfb21d | 1649 | goto good; |
44662487 | 1650 | case V_OCSP_CERTSTATUS_REVOKED: |
018058b2 | 1651 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1652 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1653 | reason != -1 ? "; reason: " : "", | |
1654 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1655 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
44662487 JH |
1656 | break; |
1657 | default: | |
018058b2 | 1658 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1659 | log_write(0, LOG_MAIN, |
1660 | "Server certificate status unknown, in OCSP stapling"); | |
44662487 JH |
1661 | break; |
1662 | } | |
f5d78688 | 1663 | } |
c8dfb21d JH |
1664 | failed: |
1665 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1666 | good: | |
f5d78688 JH |
1667 | BIO_free(bp); |
1668 | } | |
1669 | ||
1670 | OCSP_RESPONSE_free(rsp); | |
1671 | return i; | |
1672 | } | |
f2de3a33 | 1673 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1674 | |
1675 | ||
059ec3d9 PH |
1676 | /************************************************* |
1677 | * Initialize for TLS * | |
1678 | *************************************************/ | |
1679 | ||
e51c7be2 JH |
1680 | /* Called from both server and client code, to do preliminary initialization |
1681 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1682 | |
1683 | Arguments: | |
946ecbe0 | 1684 | ctxp returned SSL context |
059ec3d9 PH |
1685 | host connected host, if client; NULL if server |
1686 | dhparam DH parameter file | |
1687 | certificate certificate file | |
1688 | privatekey private key | |
f5d78688 | 1689 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1690 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1691 | cbp place to put allocated callback context |
cf0c6164 | 1692 | errstr error string pointer |
059ec3d9 PH |
1693 | |
1694 | Returns: OK/DEFER/FAIL | |
1695 | */ | |
1696 | ||
1697 | static int | |
817d9f57 | 1698 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1699 | uschar *privatekey, |
f2de3a33 | 1700 | #ifndef DISABLE_OCSP |
47195144 | 1701 | uschar *ocsp_file, /*XXX stack, in server*/ |
3f7eeb86 | 1702 | #endif |
cf0c6164 | 1703 | address_item *addr, tls_ext_ctx_cb ** cbp, uschar ** errstr) |
059ec3d9 | 1704 | { |
7006ee24 | 1705 | SSL_CTX * ctx; |
77bb000f | 1706 | long init_options; |
7be682ca | 1707 | int rc; |
a7538db1 | 1708 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1709 | |
1710 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1711 | cbinfo->certificate = certificate; | |
1712 | cbinfo->privatekey = privatekey; | |
a6510420 | 1713 | cbinfo->is_server = host==NULL; |
f2de3a33 | 1714 | #ifndef DISABLE_OCSP |
c3033f13 | 1715 | cbinfo->verify_stack = NULL; |
a6510420 | 1716 | if (!host) |
f5d78688 JH |
1717 | { |
1718 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1719 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1720 | cbinfo->u_ocsp.server.response = NULL; | |
1721 | } | |
1722 | else | |
1723 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1724 | #endif |
7be682ca | 1725 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1726 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1727 | cbinfo->host = host; |
0cbf2b82 | 1728 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1729 | cbinfo->event_action = NULL; |
1730 | #endif | |
77bb000f | 1731 | |
7434882d | 1732 | #ifdef EXIM_NEED_OPENSSL_INIT |
059ec3d9 PH |
1733 | SSL_load_error_strings(); /* basic set up */ |
1734 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 1735 | #endif |
059ec3d9 | 1736 | |
c8dfb21d | 1737 | #ifdef EXIM_HAVE_SHA256 |
77bb000f | 1738 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1739 | list of available digests. */ |
1740 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1741 | #endif |
a0475b69 | 1742 | |
f0f5a555 PP |
1743 | /* Create a context. |
1744 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1745 | negotiation in the different methods; as far as I can tell, the only | |
1746 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1747 | when OpenSSL is built without SSLv2 support. | |
1748 | By disabling with openssl_options, we can let admins re-enable with the | |
1749 | existing knob. */ | |
059ec3d9 | 1750 | |
7a8b9519 JH |
1751 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1752 | if (!(ctx = SSL_CTX_new(host ? TLS_client_method() : TLS_server_method()))) | |
1753 | #else | |
7006ee24 | 1754 | if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method()))) |
7a8b9519 | 1755 | #endif |
7006ee24 | 1756 | return tls_error(US"SSL_CTX_new", host, NULL, errstr); |
059ec3d9 PH |
1757 | |
1758 | /* It turns out that we need to seed the random number generator this early in | |
1759 | order to get the full complement of ciphers to work. It took me roughly a day | |
1760 | of work to discover this by experiment. | |
1761 | ||
1762 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1763 | there. Otherwise, we have to make something up as best we can. Double check | |
1764 | afterwards. */ | |
1765 | ||
1766 | if (!RAND_status()) | |
1767 | { | |
1768 | randstuff r; | |
9e3331ea | 1769 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1770 | r.p = getpid(); |
1771 | ||
5903c6ff JH |
1772 | RAND_seed(US (&r), sizeof(r)); |
1773 | RAND_seed(US big_buffer, big_buffer_size); | |
1774 | if (addr != NULL) RAND_seed(US addr, sizeof(addr)); | |
059ec3d9 PH |
1775 | |
1776 | if (!RAND_status()) | |
7199e1ee | 1777 | return tls_error(US"RAND_status", host, |
cf0c6164 | 1778 | US"unable to seed random number generator", errstr); |
059ec3d9 PH |
1779 | } |
1780 | ||
1781 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1782 | level. */ | |
1783 | ||
7006ee24 | 1784 | DEBUG(D_tls) SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); |
8a40db1c JH |
1785 | #ifdef OPENSSL_HAVE_KEYLOG_CB |
1786 | DEBUG(D_tls) SSL_CTX_set_keylog_callback(ctx, (void (*)())keylog_callback); | |
1787 | #endif | |
059ec3d9 | 1788 | |
c80c5570 | 1789 | /* Automatically re-try reads/writes after renegotiation. */ |
7006ee24 | 1790 | (void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1791 | |
77bb000f PP |
1792 | /* Apply administrator-supplied work-arounds. |
1793 | Historically we applied just one requested option, | |
1794 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1795 | moved to an administrator-controlled list of options to specify and | |
1796 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1797 | |
77bb000f PP |
1798 | No OpenSSL version number checks: the options we accept depend upon the |
1799 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1800 | |
7006ee24 | 1801 | if (!tls_openssl_options_parse(openssl_options, &init_options)) |
cf0c6164 | 1802 | return tls_error(US"openssl_options parsing failed", host, NULL, errstr); |
77bb000f PP |
1803 | |
1804 | if (init_options) | |
1805 | { | |
1806 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
7006ee24 | 1807 | if (!(SSL_CTX_set_options(ctx, init_options))) |
77bb000f | 1808 | return tls_error(string_sprintf( |
cf0c6164 | 1809 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL, errstr); |
77bb000f PP |
1810 | } |
1811 | else | |
1812 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 | 1813 | |
d7f31bb6 JH |
1814 | #ifdef OPENSSL_HAVE_NUM_TICKETS |
1815 | SSL_CTX_set_num_tickets(ctx, 0); /* send no TLS1.3 stateful-tickets */ | |
1816 | #endif | |
1817 | ||
a28050f8 JH |
1818 | /* We'd like to disable session cache unconditionally, but foolish Outlook |
1819 | Express clients then give up the first TLS connection and make a second one | |
1820 | (which works). Only when there is an IMAP service on the same machine. | |
1821 | Presumably OE is trying to use the cache for A on B. Leave it enabled for | |
1822 | now, until we work out a decent way of presenting control to the config. It | |
1823 | will never be used because we use a new context every time. */ | |
1824 | #ifdef notdef | |
7006ee24 | 1825 | (void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF); |
a28050f8 | 1826 | #endif |
7006ee24 | 1827 | |
059ec3d9 | 1828 | /* Initialize with DH parameters if supplied */ |
10ca4f1c | 1829 | /* Initialize ECDH temp key parameter selection */ |
059ec3d9 | 1830 | |
7006ee24 JH |
1831 | if ( !init_dh(ctx, dhparam, host, errstr) |
1832 | || !init_ecdh(ctx, host, errstr) | |
038597d2 PP |
1833 | ) |
1834 | return DEFER; | |
059ec3d9 | 1835 | |
3f7eeb86 | 1836 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1837 | |
7006ee24 | 1838 | if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK) |
23bb6982 | 1839 | return rc; |
c91535f3 | 1840 | |
c3033f13 JH |
1841 | /* If we need to handle SNI or OCSP, do so */ |
1842 | ||
3bcbbbe2 | 1843 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
c3033f13 JH |
1844 | # ifndef DISABLE_OCSP |
1845 | if (!(cbinfo->verify_stack = sk_X509_new_null())) | |
1846 | { | |
1847 | DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n"); | |
1848 | return FAIL; | |
1849 | } | |
1850 | # endif | |
1851 | ||
7a8b9519 | 1852 | if (!host) /* server */ |
3f0945ff | 1853 | { |
f2de3a33 | 1854 | # ifndef DISABLE_OCSP |
f5d78688 | 1855 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1856 | the option exists, not what the current expansion might be, as SNI might |
1857 | change the certificate and OCSP file in use between now and the time the | |
1858 | callback is invoked. */ | |
f5d78688 | 1859 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1860 | { |
7006ee24 JH |
1861 | SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb); |
1862 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
3f7eeb86 | 1863 | } |
f5d78688 | 1864 | # endif |
3f0945ff PP |
1865 | /* We always do this, so that $tls_sni is available even if not used in |
1866 | tls_certificate */ | |
7006ee24 JH |
1867 | SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); |
1868 | SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo); | |
3f0945ff | 1869 | } |
f2de3a33 | 1870 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1871 | else /* client */ |
1872 | if(ocsp_file) /* wanting stapling */ | |
1873 | { | |
1874 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1875 | { | |
1876 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1877 | return FAIL; | |
1878 | } | |
7006ee24 JH |
1879 | SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb); |
1880 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
f5d78688 JH |
1881 | } |
1882 | # endif | |
7be682ca | 1883 | #endif |
059ec3d9 | 1884 | |
e51c7be2 | 1885 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 1886 | |
c8dfb21d | 1887 | #ifdef EXIM_HAVE_EPHEM_RSA_KEX |
059ec3d9 | 1888 | /* Set up the RSA callback */ |
7006ee24 | 1889 | SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); |
c8dfb21d | 1890 | #endif |
059ec3d9 PH |
1891 | |
1892 | /* Finally, set the timeout, and we are done */ | |
1893 | ||
7006ee24 | 1894 | SSL_CTX_set_timeout(ctx, ssl_session_timeout); |
059ec3d9 | 1895 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1896 | |
817d9f57 | 1897 | *cbp = cbinfo; |
7006ee24 | 1898 | *ctxp = ctx; |
7be682ca | 1899 | |
059ec3d9 PH |
1900 | return OK; |
1901 | } | |
1902 | ||
1903 | ||
1904 | ||
1905 | ||
1906 | /************************************************* | |
1907 | * Get name of cipher in use * | |
1908 | *************************************************/ | |
1909 | ||
817d9f57 | 1910 | /* |
059ec3d9 | 1911 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1912 | buffer to use for answer |
1913 | size of buffer | |
1914 | pointer to number of bits for cipher | |
059ec3d9 PH |
1915 | Returns: nothing |
1916 | */ | |
1917 | ||
1918 | static void | |
817d9f57 | 1919 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1920 | { |
7a8b9519 | 1921 | /* With OpenSSL 1.0.0a, 'c' needs to be const but the documentation doesn't |
57b3a7f5 PP |
1922 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have |
1923 | the accessor functions use const in the prototype. */ | |
059ec3d9 | 1924 | |
7a8b9519 JH |
1925 | const uschar * ver = CUS SSL_get_version(ssl); |
1926 | const SSL_CIPHER * c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); | |
059ec3d9 | 1927 | |
817d9f57 | 1928 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1929 | |
817d9f57 JH |
1930 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1931 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1932 | |
1933 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1934 | } | |
1935 | ||
1936 | ||
f69979cf | 1937 | static void |
70e384dd | 1938 | peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned siz) |
f69979cf JH |
1939 | { |
1940 | /*XXX we might consider a list-of-certs variable for the cert chain. | |
1941 | SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support | |
1942 | in list-handling functions, also consider the difference between the entire | |
1943 | chain and the elements sent by the peer. */ | |
1944 | ||
70e384dd JH |
1945 | tlsp->peerdn = NULL; |
1946 | ||
f69979cf JH |
1947 | /* Will have already noted peercert on a verify fail; possibly not the leaf */ |
1948 | if (!tlsp->peercert) | |
1949 | tlsp->peercert = SSL_get_peer_certificate(ssl); | |
1950 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
1951 | if (tlsp->peercert) | |
70e384dd JH |
1952 | if (!X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, siz)) |
1953 | { DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); } | |
1954 | else | |
1955 | { | |
1956 | peerdn[siz-1] = '\0'; | |
1957 | tlsp->peerdn = peerdn; /*XXX a static buffer... */ | |
1958 | } | |
f69979cf JH |
1959 | } |
1960 | ||
1961 | ||
059ec3d9 PH |
1962 | |
1963 | ||
1964 | ||
1965 | /************************************************* | |
1966 | * Set up for verifying certificates * | |
1967 | *************************************************/ | |
1968 | ||
0e8aed8a | 1969 | #ifndef DISABLE_OCSP |
c3033f13 JH |
1970 | /* Load certs from file, return TRUE on success */ |
1971 | ||
1972 | static BOOL | |
1973 | chain_from_pem_file(const uschar * file, STACK_OF(X509) * verify_stack) | |
1974 | { | |
1975 | BIO * bp; | |
1976 | X509 * x; | |
1977 | ||
dec766a1 WB |
1978 | while (sk_X509_num(verify_stack) > 0) |
1979 | X509_free(sk_X509_pop(verify_stack)); | |
1980 | ||
c3033f13 JH |
1981 | if (!(bp = BIO_new_file(CS file, "r"))) return FALSE; |
1982 | while ((x = PEM_read_bio_X509(bp, NULL, 0, NULL))) | |
1983 | sk_X509_push(verify_stack, x); | |
1984 | BIO_free(bp); | |
1985 | return TRUE; | |
1986 | } | |
0e8aed8a | 1987 | #endif |
c3033f13 JH |
1988 | |
1989 | ||
1990 | ||
dec766a1 WB |
1991 | /* Called by both client and server startup; on the server possibly |
1992 | repeated after a Server Name Indication. | |
059ec3d9 PH |
1993 | |
1994 | Arguments: | |
7be682ca | 1995 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1996 | certs certs file or NULL |
1997 | crl CRL file or NULL | |
1998 | host NULL in a server; the remote host in a client | |
1999 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
2000 | otherwise passed as FALSE | |
983207c1 | 2001 | cert_vfy_cb Callback function for certificate verification |
cf0c6164 | 2002 | errstr error string pointer |
059ec3d9 PH |
2003 | |
2004 | Returns: OK/DEFER/FAIL | |
2005 | */ | |
2006 | ||
2007 | static int | |
983207c1 | 2008 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 2009 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr) |
059ec3d9 PH |
2010 | { |
2011 | uschar *expcerts, *expcrl; | |
2012 | ||
cf0c6164 | 2013 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts, errstr)) |
059ec3d9 | 2014 | return DEFER; |
57cc2785 | 2015 | DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts); |
059ec3d9 | 2016 | |
10a831a3 | 2017 | if (expcerts && *expcerts) |
059ec3d9 | 2018 | { |
10a831a3 JH |
2019 | /* Tell the library to use its compiled-in location for the system default |
2020 | CA bundle. Then add the ones specified in the config, if any. */ | |
cb1d7830 | 2021 | |
10a831a3 | 2022 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
cf0c6164 | 2023 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr); |
10a831a3 JH |
2024 | |
2025 | if (Ustrcmp(expcerts, "system") != 0) | |
059ec3d9 | 2026 | { |
cb1d7830 JH |
2027 | struct stat statbuf; |
2028 | ||
cb1d7830 JH |
2029 | if (Ustat(expcerts, &statbuf) < 0) |
2030 | { | |
2031 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2032 | "failed to stat %s for certificates", expcerts); | |
2033 | return DEFER; | |
2034 | } | |
059ec3d9 | 2035 | else |
059ec3d9 | 2036 | { |
cb1d7830 JH |
2037 | uschar *file, *dir; |
2038 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
2039 | { file = NULL; dir = expcerts; } | |
2040 | else | |
c3033f13 JH |
2041 | { |
2042 | file = expcerts; dir = NULL; | |
2043 | #ifndef DISABLE_OCSP | |
2044 | /* In the server if we will be offering an OCSP proof, load chain from | |
2045 | file for verifying the OCSP proof at load time. */ | |
2046 | ||
2047 | if ( !host | |
2048 | && statbuf.st_size > 0 | |
2049 | && server_static_cbinfo->u_ocsp.server.file | |
2050 | && !chain_from_pem_file(file, server_static_cbinfo->verify_stack) | |
2051 | ) | |
2052 | { | |
2053 | log_write(0, LOG_MAIN|LOG_PANIC, | |
57887ecc | 2054 | "failed to load cert chain from %s", file); |
c3033f13 JH |
2055 | return DEFER; |
2056 | } | |
2057 | #endif | |
2058 | } | |
cb1d7830 JH |
2059 | |
2060 | /* If a certificate file is empty, the next function fails with an | |
2061 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
2062 | certificates are recognized, but the error message is still misleading (it | |
c3033f13 | 2063 | says no certificate was supplied). But this is better. */ |
cb1d7830 | 2064 | |
f2f2c91b JH |
2065 | if ( (!file || statbuf.st_size > 0) |
2066 | && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
cf0c6164 | 2067 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr); |
cb1d7830 JH |
2068 | |
2069 | /* Load the list of CAs for which we will accept certs, for sending | |
2070 | to the client. This is only for the one-file tls_verify_certificates | |
2071 | variant. | |
d7978c0f JH |
2072 | If a list isn't loaded into the server, but some verify locations are set, |
2073 | the server end appears to make a wildcard request for client certs. | |
10a831a3 | 2074 | Meanwhile, the client library as default behaviour *ignores* the list |
cb1d7830 JH |
2075 | we send over the wire - see man SSL_CTX_set_client_cert_cb. |
2076 | Because of this, and that the dir variant is likely only used for | |
d7978c0f JH |
2077 | the public-CA bundle (not for a private CA), not worth fixing. */ |
2078 | ||
f2f2c91b | 2079 | if (file) |
cb1d7830 | 2080 | { |
2009ecca | 2081 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); |
dec766a1 WB |
2082 | |
2083 | SSL_CTX_set_client_CA_list(sctx, names); | |
f2f2c91b | 2084 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", |
cb1d7830 | 2085 | sk_X509_NAME_num(names)); |
cb1d7830 | 2086 | } |
059ec3d9 PH |
2087 | } |
2088 | } | |
2089 | ||
2090 | /* Handle a certificate revocation list. */ | |
2091 | ||
10a831a3 | 2092 | #if OPENSSL_VERSION_NUMBER > 0x00907000L |
059ec3d9 | 2093 | |
8b417f2c | 2094 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
10a831a3 | 2095 | merely reformatted it into the Exim code style.) |
8b417f2c | 2096 | |
10a831a3 JH |
2097 | "From here I changed the code to add support for multiple crl's |
2098 | in pem format in one file or to support hashed directory entries in | |
2099 | pem format instead of a file. This method now uses the library function | |
2100 | X509_STORE_load_locations to add the CRL location to the SSL context. | |
2101 | OpenSSL will then handle the verify against CA certs and CRLs by | |
2102 | itself in the verify callback." */ | |
8b417f2c | 2103 | |
cf0c6164 | 2104 | if (!expand_check(crl, US"tls_crl", &expcrl, errstr)) return DEFER; |
10a831a3 | 2105 | if (expcrl && *expcrl) |
059ec3d9 | 2106 | { |
8b417f2c PH |
2107 | struct stat statbufcrl; |
2108 | if (Ustat(expcrl, &statbufcrl) < 0) | |
2109 | { | |
2110 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2111 | "failed to stat %s for certificates revocation lists", expcrl); | |
2112 | return DEFER; | |
2113 | } | |
2114 | else | |
059ec3d9 | 2115 | { |
8b417f2c PH |
2116 | /* is it a file or directory? */ |
2117 | uschar *file, *dir; | |
7be682ca | 2118 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 2119 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 2120 | { |
8b417f2c PH |
2121 | file = NULL; |
2122 | dir = expcrl; | |
2123 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
2124 | } |
2125 | else | |
2126 | { | |
8b417f2c PH |
2127 | file = expcrl; |
2128 | dir = NULL; | |
2129 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 2130 | } |
8b417f2c | 2131 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
cf0c6164 | 2132 | return tls_error(US"X509_STORE_load_locations", host, NULL, errstr); |
8b417f2c PH |
2133 | |
2134 | /* setting the flags to check against the complete crl chain */ | |
2135 | ||
2136 | X509_STORE_set_flags(cvstore, | |
2137 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 2138 | } |
059ec3d9 PH |
2139 | } |
2140 | ||
10a831a3 | 2141 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ |
059ec3d9 PH |
2142 | |
2143 | /* If verification is optional, don't fail if no certificate */ | |
2144 | ||
7be682ca | 2145 | SSL_CTX_set_verify(sctx, |
5a2a0989 | 2146 | SSL_VERIFY_PEER | (optional ? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 2147 | cert_vfy_cb); |
059ec3d9 PH |
2148 | } |
2149 | ||
2150 | return OK; | |
2151 | } | |
2152 | ||
2153 | ||
2154 | ||
2155 | /************************************************* | |
2156 | * Start a TLS session in a server * | |
2157 | *************************************************/ | |
2158 | ||
2159 | /* This is called when Exim is running as a server, after having received | |
2160 | the STARTTLS command. It must respond to that command, and then negotiate | |
2161 | a TLS session. | |
2162 | ||
2163 | Arguments: | |
2164 | require_ciphers allowed ciphers | |
cf0c6164 | 2165 | errstr pointer to error message |
059ec3d9 PH |
2166 | |
2167 | Returns: OK on success | |
2168 | DEFER for errors before the start of the negotiation | |
4c04137d | 2169 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
2170 | continue running. |
2171 | */ | |
2172 | ||
2173 | int | |
cf0c6164 | 2174 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
2175 | { |
2176 | int rc; | |
cf0c6164 JH |
2177 | uschar * expciphers; |
2178 | tls_ext_ctx_cb * cbinfo; | |
f69979cf | 2179 | static uschar peerdn[256]; |
817d9f57 | 2180 | static uschar cipherbuf[256]; |
059ec3d9 PH |
2181 | |
2182 | /* Check for previous activation */ | |
2183 | ||
74f1a423 | 2184 | if (tls_in.active.sock >= 0) |
059ec3d9 | 2185 | { |
cf0c6164 | 2186 | tls_error(US"STARTTLS received after TLS started", NULL, US"", errstr); |
925ac8e4 | 2187 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
2188 | return FAIL; |
2189 | } | |
2190 | ||
2191 | /* Initialize the SSL library. If it fails, it will already have logged | |
2192 | the error. */ | |
2193 | ||
817d9f57 | 2194 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 2195 | #ifndef DISABLE_OCSP |
47195144 | 2196 | tls_ocsp_file, /*XXX stack*/ |
3f7eeb86 | 2197 | #endif |
cf0c6164 | 2198 | NULL, &server_static_cbinfo, errstr); |
059ec3d9 | 2199 | if (rc != OK) return rc; |
817d9f57 | 2200 | cbinfo = server_static_cbinfo; |
059ec3d9 | 2201 | |
cf0c6164 | 2202 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr)) |
059ec3d9 PH |
2203 | return FAIL; |
2204 | ||
2205 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
2206 | were historically separated by underscores. So that I can use either form in my |
2207 | tests, and also for general convenience, we turn underscores into hyphens here. | |
0c3807a8 JH |
2208 | |
2209 | XXX SSL_CTX_set_cipher_list() is replaced by SSL_CTX_set_ciphersuites() | |
2210 | for TLS 1.3 . Since we do not call it at present we get the default list: | |
2211 | TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256 | |
17c76198 | 2212 | */ |
059ec3d9 | 2213 | |
c3033f13 | 2214 | if (expciphers) |
059ec3d9 | 2215 | { |
c3033f13 | 2216 | uschar * s = expciphers; |
059ec3d9 PH |
2217 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } |
2218 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 2219 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
cf0c6164 | 2220 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr); |
7be682ca | 2221 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
2222 | } |
2223 | ||
2224 | /* If this is a host for which certificate verification is mandatory or | |
2225 | optional, set up appropriately. */ | |
2226 | ||
817d9f57 | 2227 | tls_in.certificate_verified = FALSE; |
c0635b6d | 2228 | #ifdef SUPPORT_DANE |
53a7196b JH |
2229 | tls_in.dane_verified = FALSE; |
2230 | #endif | |
a2ff477a | 2231 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
2232 | |
2233 | if (verify_check_host(&tls_verify_hosts) == OK) | |
2234 | { | |
983207c1 | 2235 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2236 | FALSE, verify_callback_server, errstr); |
059ec3d9 | 2237 | if (rc != OK) return rc; |
a2ff477a | 2238 | server_verify_optional = FALSE; |
059ec3d9 PH |
2239 | } |
2240 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
2241 | { | |
983207c1 | 2242 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2243 | TRUE, verify_callback_server, errstr); |
059ec3d9 | 2244 | if (rc != OK) return rc; |
a2ff477a | 2245 | server_verify_optional = TRUE; |
059ec3d9 PH |
2246 | } |
2247 | ||
2248 | /* Prepare for new connection */ | |
2249 | ||
cf0c6164 JH |
2250 | if (!(server_ssl = SSL_new(server_ctx))) |
2251 | return tls_error(US"SSL_new", NULL, NULL, errstr); | |
da3ad30d PP |
2252 | |
2253 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
2254 | * | |
2255 | * With the SSL_clear(), we get strange interoperability bugs with | |
2256 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
2257 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
2258 | * | |
2259 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
2260 | * session shutdown. In this case, we have a brand new object and there's no | |
2261 | * obvious reason to immediately clear it. I'm guessing that this was | |
2262 | * originally added because of incomplete initialisation which the clear fixed, | |
2263 | * in some historic release. | |
2264 | */ | |
059ec3d9 PH |
2265 | |
2266 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2267 | on connection, where outputting anything now upsets the clients and tends to | |
2268 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2269 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2270 | mode, the fflush() happens when smtp_getc() is called. */ | |
2271 | ||
817d9f57 JH |
2272 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
2273 | if (!tls_in.on_connect) | |
059ec3d9 | 2274 | { |
925ac8e4 | 2275 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
059ec3d9 PH |
2276 | fflush(smtp_out); |
2277 | } | |
2278 | ||
2279 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
2280 | that the OpenSSL library doesn't. */ | |
2281 | ||
817d9f57 JH |
2282 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
2283 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
2284 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
2285 | |
2286 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
2287 | ||
2288 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2289 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
817d9f57 | 2290 | rc = SSL_accept(server_ssl); |
c2a1bba0 | 2291 | ALARM_CLR(0); |
059ec3d9 PH |
2292 | |
2293 | if (rc <= 0) | |
2294 | { | |
cf0c6164 | 2295 | (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr); |
059ec3d9 PH |
2296 | return FAIL; |
2297 | } | |
2298 | ||
2299 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
25fa0868 JH |
2300 | ERR_clear_error(); /* Even success can leave errors in the stack. Seen with |
2301 | anon-authentication ciphersuite negociated. */ | |
059ec3d9 PH |
2302 | |
2303 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2304 | and initialize things. */ | |
2305 | ||
f69979cf JH |
2306 | peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn)); |
2307 | ||
059ec3d9 PH |
2308 | DEBUG(D_tls) |
2309 | { | |
2310 | uschar buf[2048]; | |
817d9f57 | 2311 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 | 2312 | debug_printf("Shared ciphers: %s\n", buf); |
f20cfa4a JH |
2313 | |
2314 | #ifdef EXIM_HAVE_OPENSSL_KEYLOG | |
2315 | { | |
2316 | BIO * bp = BIO_new(BIO_s_mem()); | |
2317 | uschar * s; | |
2318 | int len; | |
2319 | SSL_SESSION_print_keylog(bp, SSL_get_session(server_ssl)); | |
2320 | len = (int) BIO_get_mem_data(bp, CSS &s); | |
2321 | debug_printf("%.*s", len, s); | |
2322 | BIO_free(bp); | |
2323 | } | |
2324 | #endif | |
059ec3d9 PH |
2325 | } |
2326 | ||
f20cfa4a JH |
2327 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
2328 | tls_in.cipher = cipherbuf; | |
2329 | ||
9d1c15ef JH |
2330 | /* Record the certificate we presented */ |
2331 | { | |
2332 | X509 * crt = SSL_get_certificate(server_ssl); | |
2333 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
2334 | } | |
059ec3d9 | 2335 | |
817d9f57 JH |
2336 | /* Only used by the server-side tls (tls_in), including tls_getc. |
2337 | Client-side (tls_out) reads (seem to?) go via | |
2338 | smtp_read_response()/ip_recv(). | |
2339 | Hence no need to duplicate for _in and _out. | |
2340 | */ | |
b808677c | 2341 | if (!ssl_xfer_buffer) ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 | 2342 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; |
8b77d27a | 2343 | ssl_xfer_eof = ssl_xfer_error = FALSE; |
059ec3d9 PH |
2344 | |
2345 | receive_getc = tls_getc; | |
0d81dabc | 2346 | receive_getbuf = tls_getbuf; |
584e96c6 | 2347 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2348 | receive_ungetc = tls_ungetc; |
2349 | receive_feof = tls_feof; | |
2350 | receive_ferror = tls_ferror; | |
58eb016e | 2351 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2352 | |
74f1a423 JH |
2353 | tls_in.active.sock = fileno(smtp_out); |
2354 | tls_in.active.tls_ctx = NULL; /* not using explicit ctx for server-side */ | |
059ec3d9 PH |
2355 | return OK; |
2356 | } | |
2357 | ||
2358 | ||
2359 | ||
2360 | ||
043b1248 JH |
2361 | static int |
2362 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
cf0c6164 JH |
2363 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo, |
2364 | uschar ** errstr) | |
043b1248 JH |
2365 | { |
2366 | int rc; | |
94431adb | 2367 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
043b1248 JH |
2368 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only |
2369 | the specified host patterns if one of them is defined */ | |
2370 | ||
610ff438 JH |
2371 | if ( ( !ob->tls_verify_hosts |
2372 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2373 | ) | |
3c07dd2d | 2374 | || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK |
aa2a70ba | 2375 | ) |
043b1248 | 2376 | client_verify_optional = FALSE; |
3c07dd2d | 2377 | else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
2378 | client_verify_optional = TRUE; |
2379 | else | |
2380 | return OK; | |
2381 | ||
2382 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
cf0c6164 JH |
2383 | ob->tls_crl, host, client_verify_optional, verify_callback_client, |
2384 | errstr)) != OK) | |
aa2a70ba | 2385 | return rc; |
043b1248 | 2386 | |
3c07dd2d | 2387 | if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 2388 | { |
4af0d74a | 2389 | cbinfo->verify_cert_hostnames = |
8c5d388a | 2390 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2391 | string_domain_utf8_to_alabel(host->name, NULL); |
2392 | #else | |
2393 | host->name; | |
2394 | #endif | |
aa2a70ba JH |
2395 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", |
2396 | cbinfo->verify_cert_hostnames); | |
043b1248 | 2397 | } |
043b1248 JH |
2398 | return OK; |
2399 | } | |
059ec3d9 | 2400 | |
fde080a4 | 2401 | |
c0635b6d | 2402 | #ifdef SUPPORT_DANE |
fde080a4 | 2403 | static int |
cf0c6164 | 2404 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa, uschar ** errstr) |
fde080a4 | 2405 | { |
fde080a4 JH |
2406 | dns_scan dnss; |
2407 | const char * hostnames[2] = { CS host->name, NULL }; | |
2408 | int found = 0; | |
2409 | ||
2410 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
cf0c6164 | 2411 | return tls_error(US"hostnames load", host, NULL, errstr); |
fde080a4 | 2412 | |
d7978c0f | 2413 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; |
fde080a4 | 2414 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
1b76ad22 | 2415 | ) if (rr->type == T_TLSA && rr->size > 3) |
fde080a4 | 2416 | { |
c3033f13 | 2417 | const uschar * p = rr->data; |
fde080a4 JH |
2418 | uint8_t usage, selector, mtype; |
2419 | const char * mdname; | |
2420 | ||
fde080a4 | 2421 | usage = *p++; |
133d2546 JH |
2422 | |
2423 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
2424 | if (usage != 2 && usage != 3) continue; | |
2425 | ||
fde080a4 JH |
2426 | selector = *p++; |
2427 | mtype = *p++; | |
2428 | ||
2429 | switch (mtype) | |
2430 | { | |
133d2546 JH |
2431 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
2432 | case 0: mdname = NULL; break; | |
2433 | case 1: mdname = "sha256"; break; | |
2434 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
2435 | } |
2436 | ||
133d2546 | 2437 | found++; |
fde080a4 JH |
2438 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
2439 | { | |
2440 | default: | |
cf0c6164 | 2441 | return tls_error(US"tlsa load", host, NULL, errstr); |
c035b645 | 2442 | case 0: /* action not taken */ |
fde080a4 JH |
2443 | case 1: break; |
2444 | } | |
594706ea JH |
2445 | |
2446 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
2447 | } |
2448 | ||
2449 | if (found) | |
2450 | return OK; | |
2451 | ||
133d2546 | 2452 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 2453 | return DEFER; |
fde080a4 | 2454 | } |
c0635b6d | 2455 | #endif /*SUPPORT_DANE*/ |
fde080a4 JH |
2456 | |
2457 | ||
2458 | ||
059ec3d9 PH |
2459 | /************************************************* |
2460 | * Start a TLS session in a client * | |
2461 | *************************************************/ | |
2462 | ||
2463 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2464 | ||
2465 | Argument: | |
2466 | fd the fd of the connection | |
afdb5e9c JH |
2467 | host connected host (for messages and option-tests) |
2468 | addr the first address (for some randomness; can be NULL) | |
a7538db1 | 2469 | tb transport (always smtp) |
0e66b3b6 | 2470 | tlsa_dnsa tlsa lookup, if DANE, else null |
afdb5e9c | 2471 | tlsp record details of channel configuration here; must be non-NULL |
cf0c6164 | 2472 | errstr error string pointer |
059ec3d9 | 2473 | |
74f1a423 | 2474 | Returns: Pointer to TLS session context, or NULL on error |
059ec3d9 PH |
2475 | */ |
2476 | ||
74f1a423 | 2477 | void * |
f5d78688 | 2478 | tls_client_start(int fd, host_item *host, address_item *addr, |
cf0c6164 | 2479 | transport_instance * tb, |
c0635b6d | 2480 | #ifdef SUPPORT_DANE |
cf0c6164 | 2481 | dns_answer * tlsa_dnsa, |
0e66b3b6 | 2482 | #endif |
74f1a423 | 2483 | tls_support * tlsp, uschar ** errstr) |
059ec3d9 | 2484 | { |
afdb5e9c JH |
2485 | smtp_transport_options_block * ob = tb |
2486 | ? (smtp_transport_options_block *)tb->options_block | |
2487 | : &smtp_transport_option_defaults; | |
74f1a423 | 2488 | exim_openssl_client_tls_ctx * exim_client_ctx; |
f69979cf | 2489 | static uschar peerdn[256]; |
868f5672 | 2490 | uschar * expciphers; |
059ec3d9 | 2491 | int rc; |
817d9f57 | 2492 | static uschar cipherbuf[256]; |
043b1248 JH |
2493 | |
2494 | #ifndef DISABLE_OCSP | |
043b1248 | 2495 | BOOL request_ocsp = FALSE; |
6634ac8d | 2496 | BOOL require_ocsp = FALSE; |
043b1248 | 2497 | #endif |
043b1248 | 2498 | |
74f1a423 JH |
2499 | rc = store_pool; |
2500 | store_pool = POOL_PERM; | |
2501 | exim_client_ctx = store_get(sizeof(exim_openssl_client_tls_ctx)); | |
2502 | store_pool = rc; | |
2503 | ||
c0635b6d | 2504 | #ifdef SUPPORT_DANE |
74f1a423 | 2505 | tlsp->tlsa_usage = 0; |
043b1248 JH |
2506 | #endif |
2507 | ||
f2de3a33 | 2508 | #ifndef DISABLE_OCSP |
043b1248 | 2509 | { |
c0635b6d | 2510 | # ifdef SUPPORT_DANE |
4f59c424 JH |
2511 | if ( tlsa_dnsa |
2512 | && ob->hosts_request_ocsp[0] == '*' | |
2513 | && ob->hosts_request_ocsp[1] == '\0' | |
2514 | ) | |
2515 | { | |
2516 | /* Unchanged from default. Use a safer one under DANE */ | |
2517 | request_ocsp = TRUE; | |
2518 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
2519 | " {= {4}{$tls_out_tlsa_usage}} } " | |
2520 | " {*}{}}"; | |
2521 | } | |
2522 | # endif | |
2523 | ||
5130845b | 2524 | if ((require_ocsp = |
3c07dd2d | 2525 | verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK)) |
fca41d5a JH |
2526 | request_ocsp = TRUE; |
2527 | else | |
c0635b6d | 2528 | # ifdef SUPPORT_DANE |
4f59c424 | 2529 | if (!request_ocsp) |
fca41d5a | 2530 | # endif |
5130845b | 2531 | request_ocsp = |
3c07dd2d | 2532 | verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
043b1248 | 2533 | } |
f5d78688 | 2534 | #endif |
059ec3d9 | 2535 | |
74f1a423 | 2536 | rc = tls_init(&exim_client_ctx->ctx, host, NULL, |
65867078 | 2537 | ob->tls_certificate, ob->tls_privatekey, |
f2de3a33 | 2538 | #ifndef DISABLE_OCSP |
44662487 | 2539 | (void *)(long)request_ocsp, |
3f7eeb86 | 2540 | #endif |
cf0c6164 | 2541 | addr, &client_static_cbinfo, errstr); |
74f1a423 | 2542 | if (rc != OK) return NULL; |
059ec3d9 | 2543 | |
74f1a423 | 2544 | tlsp->certificate_verified = FALSE; |
a2ff477a | 2545 | client_verify_callback_called = FALSE; |
059ec3d9 | 2546 | |
5ec37a55 PP |
2547 | expciphers = NULL; |
2548 | #ifdef SUPPORT_DANE | |
2549 | if (tlsa_dnsa) | |
2550 | { | |
2551 | /* We fall back to tls_require_ciphers if unset, empty or forced failure, but | |
2552 | other failures should be treated as problems. */ | |
2553 | if (ob->dane_require_tls_ciphers && | |
2554 | !expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2555 | &expciphers, errstr)) | |
74f1a423 | 2556 | return NULL; |
5ec37a55 PP |
2557 | if (expciphers && *expciphers == '\0') |
2558 | expciphers = NULL; | |
2559 | } | |
2560 | #endif | |
2561 | if (!expciphers && | |
2562 | !expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", | |
2563 | &expciphers, errstr)) | |
74f1a423 | 2564 | return NULL; |
059ec3d9 PH |
2565 | |
2566 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
2567 | are separated by underscores. So that I can use either form in my tests, and | |
2568 | also for general convenience, we turn underscores into hyphens here. */ | |
2569 | ||
cf0c6164 | 2570 | if (expciphers) |
059ec3d9 PH |
2571 | { |
2572 | uschar *s = expciphers; | |
cf0c6164 | 2573 | while (*s) { if (*s == '_') *s = '-'; s++; } |
059ec3d9 | 2574 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); |
74f1a423 JH |
2575 | if (!SSL_CTX_set_cipher_list(exim_client_ctx->ctx, CS expciphers)) |
2576 | { | |
2577 | tls_error(US"SSL_CTX_set_cipher_list", host, NULL, errstr); | |
2578 | return NULL; | |
2579 | } | |
059ec3d9 PH |
2580 | } |
2581 | ||
c0635b6d | 2582 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2583 | if (tlsa_dnsa) |
a63be306 | 2584 | { |
74f1a423 | 2585 | SSL_CTX_set_verify(exim_client_ctx->ctx, |
02af313d JH |
2586 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, |
2587 | verify_callback_client_dane); | |
e5cccda9 | 2588 | |
043b1248 | 2589 | if (!DANESSL_library_init()) |
74f1a423 JH |
2590 | { |
2591 | tls_error(US"library init", host, NULL, errstr); | |
2592 | return NULL; | |
2593 | } | |
2594 | if (DANESSL_CTX_init(exim_client_ctx->ctx) <= 0) | |
2595 | { | |
2596 | tls_error(US"context init", host, NULL, errstr); | |
2597 | return NULL; | |
2598 | } | |
043b1248 JH |
2599 | } |
2600 | else | |
e51c7be2 | 2601 | |
043b1248 JH |
2602 | #endif |
2603 | ||
74f1a423 JH |
2604 | if (tls_client_basic_ctx_init(exim_client_ctx->ctx, host, ob, |
2605 | client_static_cbinfo, errstr) != OK) | |
2606 | return NULL; | |
059ec3d9 | 2607 | |
74f1a423 JH |
2608 | if (!(exim_client_ctx->ssl = SSL_new(exim_client_ctx->ctx))) |
2609 | { | |
2610 | tls_error(US"SSL_new", host, NULL, errstr); | |
2611 | return NULL; | |
2612 | } | |
2613 | SSL_set_session_id_context(exim_client_ctx->ssl, sid_ctx, Ustrlen(sid_ctx)); | |
2614 | SSL_set_fd(exim_client_ctx->ssl, fd); | |
2615 | SSL_set_connect_state(exim_client_ctx->ssl); | |
059ec3d9 | 2616 | |
65867078 | 2617 | if (ob->tls_sni) |
3f0945ff | 2618 | { |
74f1a423 JH |
2619 | if (!expand_check(ob->tls_sni, US"tls_sni", &tlsp->sni, errstr)) |
2620 | return NULL; | |
2621 | if (!tlsp->sni) | |
2c9a0e86 PP |
2622 | { |
2623 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
2624 | } | |
74f1a423 JH |
2625 | else if (!Ustrlen(tlsp->sni)) |
2626 | tlsp->sni = NULL; | |
3f0945ff PP |
2627 | else |
2628 | { | |
35731706 | 2629 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
74f1a423 JH |
2630 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tlsp->sni); |
2631 | SSL_set_tlsext_host_name(exim_client_ctx->ssl, tlsp->sni); | |
35731706 | 2632 | #else |
66802652 | 2633 | log_write(0, LOG_MAIN, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n", |
74f1a423 | 2634 | tlsp->sni); |
35731706 | 2635 | #endif |
3f0945ff PP |
2636 | } |
2637 | } | |
2638 | ||
c0635b6d | 2639 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2640 | if (tlsa_dnsa) |
74f1a423 JH |
2641 | if (dane_tlsa_load(exim_client_ctx->ssl, host, tlsa_dnsa, errstr) != OK) |
2642 | return NULL; | |
594706ea JH |
2643 | #endif |
2644 | ||
f2de3a33 | 2645 | #ifndef DISABLE_OCSP |
f5d78688 JH |
2646 | /* Request certificate status at connection-time. If the server |
2647 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
c0635b6d | 2648 | # ifdef SUPPORT_DANE |
594706ea JH |
2649 | if (request_ocsp) |
2650 | { | |
2651 | const uschar * s; | |
41afb5cb JH |
2652 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
2653 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
2654 | ) |
2655 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
2656 | this means we avoid the OCSP request, we wasted the setup | |
2657 | cost in tls_init(). */ | |
3c07dd2d | 2658 | require_ocsp = verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; |
5130845b | 2659 | request_ocsp = require_ocsp |
3c07dd2d | 2660 | || verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
594706ea JH |
2661 | } |
2662 | } | |
b50c8b84 JH |
2663 | # endif |
2664 | ||
44662487 JH |
2665 | if (request_ocsp) |
2666 | { | |
74f1a423 | 2667 | SSL_set_tlsext_status_type(exim_client_ctx->ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 | 2668 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
74f1a423 | 2669 | tlsp->ocsp = OCSP_NOT_RESP; |
44662487 | 2670 | } |
f5d78688 JH |
2671 | #endif |
2672 | ||
0cbf2b82 | 2673 | #ifndef DISABLE_EVENT |
afdb5e9c | 2674 | client_static_cbinfo->event_action = tb ? tb->event_action : NULL; |
a7538db1 | 2675 | #endif |
043b1248 | 2676 | |
059ec3d9 PH |
2677 | /* There doesn't seem to be a built-in timeout on connection. */ |
2678 | ||
2679 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
2680 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2681 | ALARM(ob->command_timeout); |
74f1a423 | 2682 | rc = SSL_connect(exim_client_ctx->ssl); |
c2a1bba0 | 2683 | ALARM_CLR(0); |
059ec3d9 | 2684 | |
c0635b6d | 2685 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2686 | if (tlsa_dnsa) |
74f1a423 | 2687 | DANESSL_cleanup(exim_client_ctx->ssl); |
043b1248 JH |
2688 | #endif |
2689 | ||
059ec3d9 | 2690 | if (rc <= 0) |
74f1a423 JH |
2691 | { |
2692 | tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL, errstr); | |
2693 | return NULL; | |
2694 | } | |
059ec3d9 | 2695 | |
f20cfa4a JH |
2696 | DEBUG(D_tls) |
2697 | { | |
2698 | debug_printf("SSL_connect succeeded\n"); | |
2699 | #ifdef EXIM_HAVE_OPENSSL_KEYLOG | |
2700 | { | |
2701 | BIO * bp = BIO_new(BIO_s_mem()); | |
2702 | uschar * s; | |
2703 | int len; | |
2704 | SSL_SESSION_print_keylog(bp, SSL_get_session(server_ssl)); | |
2705 | len = (int) BIO_get_mem_data(bp, CSS &s); | |
2706 | debug_printf("%.*s", len, s); | |
2707 | BIO_free(bp); | |
2708 | } | |
2709 | #endif | |
2710 | } | |
059ec3d9 | 2711 | |
74f1a423 | 2712 | peer_cert(exim_client_ctx->ssl, tlsp, peerdn, sizeof(peerdn)); |
059ec3d9 | 2713 | |
74f1a423 JH |
2714 | construct_cipher_name(exim_client_ctx->ssl, cipherbuf, sizeof(cipherbuf), &tlsp->bits); |
2715 | tlsp->cipher = cipherbuf; | |
059ec3d9 | 2716 | |
9d1c15ef JH |
2717 | /* Record the certificate we presented */ |
2718 | { | |
74f1a423 JH |
2719 | X509 * crt = SSL_get_certificate(exim_client_ctx->ssl); |
2720 | tlsp->ourcert = crt ? X509_dup(crt) : NULL; | |
9d1c15ef JH |
2721 | } |
2722 | ||
74f1a423 JH |
2723 | tlsp->active.sock = fd; |
2724 | tlsp->active.tls_ctx = exim_client_ctx; | |
2725 | return exim_client_ctx; | |
059ec3d9 PH |
2726 | } |
2727 | ||
2728 | ||
2729 | ||
2730 | ||
2731 | ||
0d81dabc JH |
2732 | static BOOL |
2733 | tls_refill(unsigned lim) | |
2734 | { | |
2735 | int error; | |
2736 | int inbytes; | |
2737 | ||
2738 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, | |
2739 | ssl_xfer_buffer, ssl_xfer_buffer_size); | |
2740 | ||
c2a1bba0 | 2741 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
0d81dabc JH |
2742 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, |
2743 | MIN(ssl_xfer_buffer_size, lim)); | |
2744 | error = SSL_get_error(server_ssl, inbytes); | |
c2a1bba0 | 2745 | if (smtp_receive_timeout > 0) ALARM_CLR(0); |
9723f966 JH |
2746 | |
2747 | if (had_command_timeout) /* set by signal handler */ | |
2748 | smtp_command_timeout_exit(); /* does not return */ | |
2749 | if (had_command_sigterm) | |
2750 | smtp_command_sigterm_exit(); | |
2751 | if (had_data_timeout) | |
2752 | smtp_data_timeout_exit(); | |
2753 | if (had_data_sigint) | |
2754 | smtp_data_sigint_exit(); | |
0d81dabc JH |
2755 | |
2756 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2757 | closed down, not that the socket itself has been closed down. Revert to | |
2758 | non-SSL handling. */ | |
2759 | ||
74f1a423 | 2760 | switch(error) |
0d81dabc | 2761 | { |
74f1a423 JH |
2762 | case SSL_ERROR_NONE: |
2763 | break; | |
2764 | ||
2765 | case SSL_ERROR_ZERO_RETURN: | |
2766 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
0d81dabc | 2767 | |
74f1a423 JH |
2768 | receive_getc = smtp_getc; |
2769 | receive_getbuf = smtp_getbuf; | |
2770 | receive_get_cache = smtp_get_cache; | |
2771 | receive_ungetc = smtp_ungetc; | |
2772 | receive_feof = smtp_feof; | |
2773 | receive_ferror = smtp_ferror; | |
2774 | receive_smtp_buffered = smtp_buffered; | |
0d81dabc | 2775 | |
74f1a423 JH |
2776 | if (SSL_get_shutdown(server_ssl) == SSL_RECEIVED_SHUTDOWN) |
2777 | SSL_shutdown(server_ssl); | |
dec766a1 | 2778 | |
37f0ce65 | 2779 | #ifndef DISABLE_OCSP |
74f1a423 JH |
2780 | sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free); |
2781 | server_static_cbinfo->verify_stack = NULL; | |
37f0ce65 | 2782 | #endif |
74f1a423 JH |
2783 | SSL_free(server_ssl); |
2784 | SSL_CTX_free(server_ctx); | |
2785 | server_ctx = NULL; | |
2786 | server_ssl = NULL; | |
2787 | tls_in.active.sock = -1; | |
2788 | tls_in.active.tls_ctx = NULL; | |
2789 | tls_in.bits = 0; | |
2790 | tls_in.cipher = NULL; | |
2791 | tls_in.peerdn = NULL; | |
2792 | tls_in.sni = NULL; | |
0d81dabc | 2793 | |
74f1a423 | 2794 | return FALSE; |
0d81dabc | 2795 | |
74f1a423 JH |
2796 | /* Handle genuine errors */ |
2797 | case SSL_ERROR_SSL: | |
0abc5a13 | 2798 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
74f1a423 JH |
2799 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
2800 | ssl_xfer_error = TRUE; | |
2801 | return FALSE; | |
0d81dabc | 2802 | |
74f1a423 JH |
2803 | default: |
2804 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2805 | DEBUG(D_tls) if (error == SSL_ERROR_SYSCALL) | |
2806 | debug_printf(" - syscall %s\n", strerror(errno)); | |
2807 | ssl_xfer_error = TRUE; | |
2808 | return FALSE; | |
0d81dabc JH |
2809 | } |
2810 | ||
2811 | #ifndef DISABLE_DKIM | |
2812 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2813 | #endif | |
2814 | ssl_xfer_buffer_hwm = inbytes; | |
2815 | ssl_xfer_buffer_lwm = 0; | |
2816 | return TRUE; | |
2817 | } | |
2818 | ||
2819 | ||
059ec3d9 PH |
2820 | /************************************************* |
2821 | * TLS version of getc * | |
2822 | *************************************************/ | |
2823 | ||
2824 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2825 | it refills the buffer via the SSL reading function. | |
2826 | ||
bd8fbe36 | 2827 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 | 2828 | Returns: the next character or EOF |
817d9f57 JH |
2829 | |
2830 | Only used by the server-side TLS. | |
059ec3d9 PH |
2831 | */ |
2832 | ||
2833 | int | |
bd8fbe36 | 2834 | tls_getc(unsigned lim) |
059ec3d9 PH |
2835 | { |
2836 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
0d81dabc JH |
2837 | if (!tls_refill(lim)) |
2838 | return ssl_xfer_error ? EOF : smtp_getc(lim); | |
059ec3d9 | 2839 | |
0d81dabc | 2840 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2841 | |
0d81dabc JH |
2842 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; |
2843 | } | |
059ec3d9 | 2844 | |
0d81dabc JH |
2845 | uschar * |
2846 | tls_getbuf(unsigned * len) | |
2847 | { | |
2848 | unsigned size; | |
2849 | uschar * buf; | |
ba084640 | 2850 | |
0d81dabc JH |
2851 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) |
2852 | if (!tls_refill(*len)) | |
059ec3d9 | 2853 | { |
0d81dabc JH |
2854 | if (!ssl_xfer_error) return smtp_getbuf(len); |
2855 | *len = 0; | |
2856 | return NULL; | |
059ec3d9 | 2857 | } |
c80c5570 | 2858 | |
0d81dabc JH |
2859 | if ((size = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm) > *len) |
2860 | size = *len; | |
2861 | buf = &ssl_xfer_buffer[ssl_xfer_buffer_lwm]; | |
2862 | ssl_xfer_buffer_lwm += size; | |
2863 | *len = size; | |
2864 | return buf; | |
059ec3d9 PH |
2865 | } |
2866 | ||
0d81dabc | 2867 | |
584e96c6 JH |
2868 | void |
2869 | tls_get_cache() | |
2870 | { | |
9960d1e5 | 2871 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2872 | int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm; |
2873 | if (n > 0) | |
2874 | dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n); | |
584e96c6 | 2875 | #endif |
9960d1e5 | 2876 | } |
584e96c6 | 2877 | |
059ec3d9 | 2878 | |
925ac8e4 JH |
2879 | BOOL |
2880 | tls_could_read(void) | |
2881 | { | |
a5ffa9b4 | 2882 | return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(server_ssl) > 0; |
925ac8e4 JH |
2883 | } |
2884 | ||
059ec3d9 PH |
2885 | |
2886 | /************************************************* | |
2887 | * Read bytes from TLS channel * | |
2888 | *************************************************/ | |
2889 | ||
2890 | /* | |
2891 | Arguments: | |
74f1a423 | 2892 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2893 | buff buffer of data |
2894 | len size of buffer | |
2895 | ||
2896 | Returns: the number of bytes read | |
afdb5e9c | 2897 | -1 after a failed read, including EOF |
817d9f57 JH |
2898 | |
2899 | Only used by the client-side TLS. | |
059ec3d9 PH |
2900 | */ |
2901 | ||
2902 | int | |
74f1a423 | 2903 | tls_read(void * ct_ctx, uschar *buff, size_t len) |
059ec3d9 | 2904 | { |
74f1a423 | 2905 | SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; |
059ec3d9 PH |
2906 | int inbytes; |
2907 | int error; | |
2908 | ||
389ca47a | 2909 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2910 | buff, (unsigned int)len); |
059ec3d9 | 2911 | |
389ca47a JH |
2912 | inbytes = SSL_read(ssl, CS buff, len); |
2913 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2914 | |
2915 | if (error == SSL_ERROR_ZERO_RETURN) | |
2916 | { | |
2917 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2918 | return -1; | |
2919 | } | |
2920 | else if (error != SSL_ERROR_NONE) | |
059ec3d9 | 2921 | return -1; |
059ec3d9 PH |
2922 | |
2923 | return inbytes; | |
2924 | } | |
2925 | ||
2926 | ||
2927 | ||
2928 | ||
2929 | ||
2930 | /************************************************* | |
2931 | * Write bytes down TLS channel * | |
2932 | *************************************************/ | |
2933 | ||
2934 | /* | |
2935 | Arguments: | |
74f1a423 | 2936 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2937 | buff buffer of data |
2938 | len number of bytes | |
925ac8e4 | 2939 | more further data expected soon |
059ec3d9 PH |
2940 | |
2941 | Returns: the number of bytes after a successful write, | |
2942 | -1 after a failed write | |
817d9f57 JH |
2943 | |
2944 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2945 | */ |
2946 | ||
2947 | int | |
74f1a423 | 2948 | tls_write(void * ct_ctx, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2949 | { |
ac35befe | 2950 | size_t olen = len; |
d7978c0f | 2951 | int outbytes, error; |
74f1a423 | 2952 | SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; |
acec9514 | 2953 | static gstring * corked = NULL; |
a5ffa9b4 | 2954 | |
ef698bf6 | 2955 | DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__, |
b93be52e | 2956 | buff, (unsigned long)len, more ? ", more" : ""); |
a5ffa9b4 JH |
2957 | |
2958 | /* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when | |
2959 | "more" is notified. This hack is only ok if small amounts are involved AND only | |
2960 | one stream does it, in one context (i.e. no store reset). Currently it is used | |
2961 | for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. */ | |
ac35befe JH |
2962 | /* + if PIPE_COMMAND, banner & ehlo-resp for smmtp-on-connect. Suspect there's |
2963 | a store reset there, so use POOL_PERM. */ | |
2964 | /* + if CHUNKING, cmds EHLO,MAIL,RCPT(s),BDAT */ | |
a5ffa9b4 | 2965 | |
ac35befe | 2966 | if ((more || corked)) |
a5ffa9b4 | 2967 | { |
ee8b8090 JH |
2968 | #ifdef EXPERIMENTAL_PIPE_CONNECT |
2969 | int save_pool = store_pool; | |
2970 | store_pool = POOL_PERM; | |
2971 | #endif | |
2972 | ||
acec9514 | 2973 | corked = string_catn(corked, buff, len); |
ee8b8090 JH |
2974 | |
2975 | #ifdef EXPERIMENTAL_PIPE_CONNECT | |
2976 | store_pool = save_pool; | |
2977 | #endif | |
2978 | ||
a5ffa9b4 JH |
2979 | if (more) |
2980 | return len; | |
acec9514 JH |
2981 | buff = CUS corked->s; |
2982 | len = corked->ptr; | |
2983 | corked = NULL; | |
a5ffa9b4 | 2984 | } |
059ec3d9 | 2985 | |
d7978c0f | 2986 | for (int left = len; left > 0;) |
059ec3d9 | 2987 | { |
74f1a423 | 2988 | DEBUG(D_tls) debug_printf("SSL_write(%p, %p, %d)\n", ssl, buff, left); |
059ec3d9 PH |
2989 | outbytes = SSL_write(ssl, CS buff, left); |
2990 | error = SSL_get_error(ssl, outbytes); | |
2991 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2992 | switch (error) | |
2993 | { | |
2994 | case SSL_ERROR_SSL: | |
0abc5a13 | 2995 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
96f5fe4c JH |
2996 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); |
2997 | return -1; | |
059ec3d9 PH |
2998 | |
2999 | case SSL_ERROR_NONE: | |
96f5fe4c JH |
3000 | left -= outbytes; |
3001 | buff += outbytes; | |
3002 | break; | |
059ec3d9 PH |
3003 | |
3004 | case SSL_ERROR_ZERO_RETURN: | |
96f5fe4c JH |
3005 | log_write(0, LOG_MAIN, "SSL channel closed on write"); |
3006 | return -1; | |
059ec3d9 | 3007 | |
817d9f57 | 3008 | case SSL_ERROR_SYSCALL: |
96f5fe4c JH |
3009 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", |
3010 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
3011 | strerror(errno)); | |
3012 | return -1; | |
817d9f57 | 3013 | |
059ec3d9 | 3014 | default: |
96f5fe4c JH |
3015 | log_write(0, LOG_MAIN, "SSL_write error %d", error); |
3016 | return -1; | |
059ec3d9 PH |
3017 | } |
3018 | } | |
ac35befe | 3019 | return olen; |
059ec3d9 PH |
3020 | } |
3021 | ||
3022 | ||
3023 | ||
3024 | /************************************************* | |
3025 | * Close down a TLS session * | |
3026 | *************************************************/ | |
3027 | ||
3028 | /* This is also called from within a delivery subprocess forked from the | |
3029 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
3030 | would tamper with the SSL session in the parent process). | |
3031 | ||
dec766a1 | 3032 | Arguments: |
74f1a423 | 3033 | ct_ctx client TLS context pointer, or NULL for the one global server context |
dec766a1 WB |
3034 | shutdown 1 if TLS close-alert is to be sent, |
3035 | 2 if also response to be waited for | |
3036 | ||
059ec3d9 | 3037 | Returns: nothing |
817d9f57 JH |
3038 | |
3039 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
3040 | */ |
3041 | ||
3042 | void | |
74f1a423 | 3043 | tls_close(void * ct_ctx, int shutdown) |
059ec3d9 | 3044 | { |
74f1a423 JH |
3045 | exim_openssl_client_tls_ctx * o_ctx = ct_ctx; |
3046 | SSL_CTX **ctxp = o_ctx ? &o_ctx->ctx : &server_ctx; | |
3047 | SSL **sslp = o_ctx ? &o_ctx->ssl : &server_ssl; | |
3048 | int *fdp = o_ctx ? &tls_out.active.sock : &tls_in.active.sock; | |
817d9f57 JH |
3049 | |
3050 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
3051 | |
3052 | if (shutdown) | |
3053 | { | |
dec766a1 WB |
3054 | int rc; |
3055 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", | |
3056 | shutdown > 1 ? " (with response-wait)" : ""); | |
3057 | ||
3058 | if ( (rc = SSL_shutdown(*sslp)) == 0 /* send "close notify" alert */ | |
3059 | && shutdown > 1) | |
3060 | { | |
c2a1bba0 | 3061 | ALARM(2); |
dec766a1 | 3062 | rc = SSL_shutdown(*sslp); /* wait for response */ |
c2a1bba0 | 3063 | ALARM_CLR(0); |
dec766a1 WB |
3064 | } |
3065 | ||
3066 | if (rc < 0) DEBUG(D_tls) | |
3067 | { | |
0abc5a13 | 3068 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
dec766a1 WB |
3069 | debug_printf("SSL_shutdown: %s\n", ssl_errstring); |
3070 | } | |
3071 | } | |
3072 | ||
37f0ce65 | 3073 | #ifndef DISABLE_OCSP |
74f1a423 | 3074 | if (!o_ctx) /* server side */ |
dec766a1 WB |
3075 | { |
3076 | sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free); | |
dec766a1 | 3077 | server_static_cbinfo->verify_stack = NULL; |
059ec3d9 | 3078 | } |
37f0ce65 | 3079 | #endif |
059ec3d9 | 3080 | |
dec766a1 | 3081 | SSL_CTX_free(*ctxp); |
817d9f57 | 3082 | SSL_free(*sslp); |
dec766a1 | 3083 | *ctxp = NULL; |
817d9f57 | 3084 | *sslp = NULL; |
817d9f57 | 3085 | *fdp = -1; |
059ec3d9 PH |
3086 | } |
3087 | ||
36f12725 NM |
3088 | |
3089 | ||
3090 | ||
3375e053 PP |
3091 | /************************************************* |
3092 | * Let tls_require_ciphers be checked at startup * | |
3093 | *************************************************/ | |
3094 | ||
3095 | /* The tls_require_ciphers option, if set, must be something which the | |
3096 | library can parse. | |
3097 | ||
3098 | Returns: NULL on success, or error message | |
3099 | */ | |
3100 | ||
3101 | uschar * | |
3102 | tls_validate_require_cipher(void) | |
3103 | { | |
3104 | SSL_CTX *ctx; | |
3105 | uschar *s, *expciphers, *err; | |
3106 | ||
3107 | /* this duplicates from tls_init(), we need a better "init just global | |
3108 | state, for no specific purpose" singleton function of our own */ | |
3109 | ||
7434882d | 3110 | #ifdef EXIM_NEED_OPENSSL_INIT |
3375e053 PP |
3111 | SSL_load_error_strings(); |
3112 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 3113 | #endif |
3375e053 PP |
3114 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
3115 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
3116 | list of available digests. */ | |
3117 | EVP_add_digest(EVP_sha256()); | |
3118 | #endif | |
3119 | ||
3120 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
3121 | return NULL; | |
3122 | ||
cf0c6164 JH |
3123 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
3124 | &err)) | |
3375e053 PP |
3125 | return US"failed to expand tls_require_ciphers"; |
3126 | ||
3127 | if (!(expciphers && *expciphers)) | |
3128 | return NULL; | |
3129 | ||
3130 | /* normalisation ripped from above */ | |
3131 | s = expciphers; | |
3132 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
3133 | ||
3134 | err = NULL; | |
3135 | ||
7a8b9519 JH |
3136 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
3137 | if (!(ctx = SSL_CTX_new(TLS_server_method()))) | |
3138 | #else | |
3139 | if (!(ctx = SSL_CTX_new(SSLv23_server_method()))) | |
3140 | #endif | |
3375e053 | 3141 | { |
0abc5a13 | 3142 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3375e053 PP |
3143 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); |
3144 | } | |
3145 | ||
3146 | DEBUG(D_tls) | |
3147 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
3148 | ||
3149 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
3150 | { | |
0abc5a13 | 3151 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 JH |
3152 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s", |
3153 | expciphers, ssl_errstring); | |
3375e053 PP |
3154 | } |
3155 | ||
3156 | SSL_CTX_free(ctx); | |
3157 | ||
3158 | return err; | |
3159 | } | |
3160 | ||
3161 | ||
3162 | ||
3163 | ||
36f12725 NM |
3164 | /************************************************* |
3165 | * Report the library versions. * | |
3166 | *************************************************/ | |
3167 | ||
3168 | /* There have historically been some issues with binary compatibility in | |
3169 | OpenSSL libraries; if Exim (like many other applications) is built against | |
3170 | one version of OpenSSL but the run-time linker picks up another version, | |
3171 | it can result in serious failures, including crashing with a SIGSEGV. So | |
3172 | report the version found by the compiler and the run-time version. | |
3173 | ||
f64a1e23 PP |
3174 | Note: some OS vendors backport security fixes without changing the version |
3175 | number/string, and the version date remains unchanged. The _build_ date | |
3176 | will change, so we can more usefully assist with version diagnosis by also | |
3177 | reporting the build date. | |
3178 | ||
36f12725 NM |
3179 | Arguments: a FILE* to print the results to |
3180 | Returns: nothing | |
3181 | */ | |
3182 | ||
3183 | void | |
3184 | tls_version_report(FILE *f) | |
3185 | { | |
754a0503 | 3186 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
3187 | " Runtime: %s\n" |
3188 | " : %s\n", | |
754a0503 | 3189 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
3190 | SSLeay_version(SSLEAY_VERSION), |
3191 | SSLeay_version(SSLEAY_BUILT_ON)); | |
3192 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
3193 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
3194 | } |
3195 | ||
9e3331ea TK |
3196 | |
3197 | ||
3198 | ||
3199 | /************************************************* | |
17c76198 | 3200 | * Random number generation * |
9e3331ea TK |
3201 | *************************************************/ |
3202 | ||
3203 | /* Pseudo-random number generation. The result is not expected to be | |
3204 | cryptographically strong but not so weak that someone will shoot themselves | |
3205 | in the foot using it as a nonce in input in some email header scheme or | |
3206 | whatever weirdness they'll twist this into. The result should handle fork() | |
3207 | and avoid repeating sequences. OpenSSL handles that for us. | |
3208 | ||
3209 | Arguments: | |
3210 | max range maximum | |
3211 | Returns a random number in range [0, max-1] | |
3212 | */ | |
3213 | ||
3214 | int | |
17c76198 | 3215 | vaguely_random_number(int max) |
9e3331ea TK |
3216 | { |
3217 | unsigned int r; | |
3218 | int i, needed_len; | |
de6135a0 PP |
3219 | static pid_t pidlast = 0; |
3220 | pid_t pidnow; | |
9e3331ea TK |
3221 | uschar smallbuf[sizeof(r)]; |
3222 | ||
3223 | if (max <= 1) | |
3224 | return 0; | |
3225 | ||
de6135a0 PP |
3226 | pidnow = getpid(); |
3227 | if (pidnow != pidlast) | |
3228 | { | |
3229 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
3230 | is unique for each thread", this doesn't apparently apply across processes, | |
3231 | so our own warning from vaguely_random_number_fallback() applies here too. | |
3232 | Fix per PostgreSQL. */ | |
3233 | if (pidlast != 0) | |
3234 | RAND_cleanup(); | |
3235 | pidlast = pidnow; | |
3236 | } | |
3237 | ||
9e3331ea TK |
3238 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
3239 | if (!RAND_status()) | |
3240 | { | |
3241 | randstuff r; | |
3242 | gettimeofday(&r.tv, NULL); | |
3243 | r.p = getpid(); | |
3244 | ||
5903c6ff | 3245 | RAND_seed(US (&r), sizeof(r)); |
9e3331ea TK |
3246 | } |
3247 | /* We're after pseudo-random, not random; if we still don't have enough data | |
3248 | in the internal PRNG then our options are limited. We could sleep and hope | |
3249 | for entropy to come along (prayer technique) but if the system is so depleted | |
3250 | in the first place then something is likely to just keep taking it. Instead, | |
3251 | we'll just take whatever little bit of pseudo-random we can still manage to | |
3252 | get. */ | |
3253 | ||
3254 | needed_len = sizeof(r); | |
3255 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
3256 | asked for a number less than 10. */ | |
3257 | for (r = max, i = 0; r; ++i) | |
3258 | r >>= 1; | |
3259 | i = (i + 7) / 8; | |
3260 | if (i < needed_len) | |
3261 | needed_len = i; | |
3262 | ||
c8dfb21d | 3263 | #ifdef EXIM_HAVE_RAND_PSEUDO |
9e3331ea | 3264 | /* We do not care if crypto-strong */ |
17c76198 | 3265 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
c8dfb21d JH |
3266 | #else |
3267 | i = RAND_bytes(smallbuf, needed_len); | |
3268 | #endif | |
3269 | ||
17c76198 PP |
3270 | if (i < 0) |
3271 | { | |
3272 | DEBUG(D_all) | |
3273 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
3274 | return vaguely_random_number_fallback(max); | |
3275 | } | |
3276 | ||
9e3331ea | 3277 | r = 0; |
d7978c0f JH |
3278 | for (uschar * p = smallbuf; needed_len; --needed_len, ++p) |
3279 | r = 256 * r + *p; | |
9e3331ea TK |
3280 | |
3281 | /* We don't particularly care about weighted results; if someone wants | |
3282 | smooth distribution and cares enough then they should submit a patch then. */ | |
3283 | return r % max; | |
3284 | } | |
3285 | ||
77bb000f PP |
3286 | |
3287 | ||
3288 | ||
3289 | /************************************************* | |
3290 | * OpenSSL option parse * | |
3291 | *************************************************/ | |
3292 | ||
3293 | /* Parse one option for tls_openssl_options_parse below | |
3294 | ||
3295 | Arguments: | |
3296 | name one option name | |
3297 | value place to store a value for it | |
3298 | Returns success or failure in parsing | |
3299 | */ | |
3300 | ||
77bb000f | 3301 | |
c80c5570 | 3302 | |
77bb000f PP |
3303 | static BOOL |
3304 | tls_openssl_one_option_parse(uschar *name, long *value) | |
3305 | { | |
3306 | int first = 0; | |
3307 | int last = exim_openssl_options_size; | |
3308 | while (last > first) | |
3309 | { | |
3310 | int middle = (first + last)/2; | |
3311 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
3312 | if (c == 0) | |
3313 | { | |
3314 | *value = exim_openssl_options[middle].value; | |
3315 | return TRUE; | |
3316 | } | |
3317 | else if (c > 0) | |
3318 | first = middle + 1; | |
3319 | else | |
3320 | last = middle; | |
3321 | } | |
3322 | return FALSE; | |
3323 | } | |
3324 | ||
3325 | ||
3326 | ||
3327 | ||
3328 | /************************************************* | |
3329 | * OpenSSL option parsing logic * | |
3330 | *************************************************/ | |
3331 | ||
3332 | /* OpenSSL has a number of compatibility options which an administrator might | |
3333 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
3334 | we look like log_selector. | |
3335 | ||
3336 | Arguments: | |
3337 | option_spec the administrator-supplied string of options | |
3338 | results ptr to long storage for the options bitmap | |
3339 | Returns success or failure | |
3340 | */ | |
3341 | ||
3342 | BOOL | |
3343 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
3344 | { | |
3345 | long result, item; | |
d7978c0f | 3346 | uschar *end; |
77bb000f PP |
3347 | uschar keep_c; |
3348 | BOOL adding, item_parsed; | |
3349 | ||
7006ee24 | 3350 | result = SSL_OP_NO_TICKET; |
b1770b6e | 3351 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 3352 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
3353 | #ifdef SSL_OP_NO_SSLv2 |
3354 | result |= SSL_OP_NO_SSLv2; | |
3355 | #endif | |
a57b6200 JH |
3356 | #ifdef SSL_OP_SINGLE_DH_USE |
3357 | result |= SSL_OP_SINGLE_DH_USE; | |
3358 | #endif | |
77bb000f | 3359 | |
7006ee24 | 3360 | if (!option_spec) |
77bb000f PP |
3361 | { |
3362 | *results = result; | |
3363 | return TRUE; | |
3364 | } | |
3365 | ||
d7978c0f | 3366 | for (uschar * s = option_spec; *s != '\0'; /**/) |
77bb000f PP |
3367 | { |
3368 | while (isspace(*s)) ++s; | |
3369 | if (*s == '\0') | |
3370 | break; | |
3371 | if (*s != '+' && *s != '-') | |
3372 | { | |
3373 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 3374 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
3375 | return FALSE; |
3376 | } | |
3377 | adding = *s++ == '+'; | |
3378 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
3379 | keep_c = *end; | |
3380 | *end = '\0'; | |
3381 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
96f5fe4c | 3382 | *end = keep_c; |
77bb000f PP |
3383 | if (!item_parsed) |
3384 | { | |
0e944a0d | 3385 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
3386 | return FALSE; |
3387 | } | |
3388 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
3389 | adding ? "adding" : "removing", result, item, s); | |
3390 | if (adding) | |
3391 | result |= item; | |
3392 | else | |
3393 | result &= ~item; | |
77bb000f PP |
3394 | s = end; |
3395 | } | |
3396 | ||
3397 | *results = result; | |
3398 | return TRUE; | |
3399 | } | |
3400 | ||
8442641e | 3401 | #endif /*!MACRO_PREDEF*/ |
9d1c15ef JH |
3402 | /* vi: aw ai sw=2 |
3403 | */ | |
059ec3d9 | 3404 | /* End of tls-openssl.c */ |