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 |
7434882d JH |
73 | # else |
74 | # define EXIM_NEED_OPENSSL_INIT | |
34e3241d PP |
75 | # endif |
76 | # if OPENSSL_VERSION_NUMBER >= 0x010000000L \ | |
2dfb468b | 77 | && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L |
34e3241d PP |
78 | # define EXIM_HAVE_OPENSSL_CHECKHOST |
79 | # endif | |
11aa88b0 | 80 | #endif |
10ca4f1c | 81 | |
11aa88b0 RA |
82 | #if !defined(LIBRESSL_VERSION_NUMBER) \ |
83 | || LIBRESSL_VERSION_NUMBER >= 0x20010000L | |
10ca4f1c JH |
84 | # if !defined(OPENSSL_NO_ECDH) |
85 | # if OPENSSL_VERSION_NUMBER >= 0x0090800fL | |
8442641e | 86 | # define EXIM_HAVE_ECDH |
10ca4f1c JH |
87 | # endif |
88 | # if OPENSSL_VERSION_NUMBER >= 0x10002000L | |
10ca4f1c JH |
89 | # define EXIM_HAVE_OPENSSL_EC_NIST2NID |
90 | # endif | |
91 | # endif | |
2dfb468b | 92 | #endif |
3bcbbbe2 | 93 | |
8a40db1c JH |
94 | #ifndef LIBRESSL_VERSION_NUMBER |
95 | # if OPENSSL_VERSION_NUMBER >= 0x010101000L | |
96 | # define OPENSSL_HAVE_KEYLOG_CB | |
d7f31bb6 | 97 | # define OPENSSL_HAVE_NUM_TICKETS |
8a40db1c JH |
98 | # endif |
99 | #endif | |
100 | ||
67791ce4 JH |
101 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
102 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
103 | # define DISABLE_OCSP | |
104 | #endif | |
105 | ||
a6510420 JH |
106 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
107 | # include <openssl/x509v3.h> | |
108 | #endif | |
109 | ||
8442641e JH |
110 | /************************************************* |
111 | * OpenSSL option parse * | |
112 | *************************************************/ | |
113 | ||
114 | typedef struct exim_openssl_option { | |
115 | uschar *name; | |
116 | long value; | |
117 | } exim_openssl_option; | |
118 | /* We could use a macro to expand, but we need the ifdef and not all the | |
119 | options document which version they were introduced in. Policylet: include | |
120 | all options unless explicitly for DTLS, let the administrator choose which | |
121 | to apply. | |
122 | ||
123 | This list is current as of: | |
124 | ==> 1.0.1b <== | |
125 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
126 | Plus SSL_OP_NO_TLSv1_3 for 1.1.2-dev | |
127 | */ | |
128 | static exim_openssl_option exim_openssl_options[] = { | |
129 | /* KEEP SORTED ALPHABETICALLY! */ | |
130 | #ifdef SSL_OP_ALL | |
131 | { US"all", SSL_OP_ALL }, | |
132 | #endif | |
133 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
134 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, | |
135 | #endif | |
136 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
137 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, | |
138 | #endif | |
139 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
140 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, | |
141 | #endif | |
142 | #ifdef SSL_OP_EPHEMERAL_RSA | |
143 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, | |
144 | #endif | |
145 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
146 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, | |
147 | #endif | |
148 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
149 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, | |
150 | #endif | |
151 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
152 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, | |
153 | #endif | |
154 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
155 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, | |
156 | #endif | |
157 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
158 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, | |
159 | #endif | |
160 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
161 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, | |
162 | #endif | |
163 | #ifdef SSL_OP_NO_COMPRESSION | |
164 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
165 | #endif | |
166 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION | |
167 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, | |
168 | #endif | |
169 | #ifdef SSL_OP_NO_SSLv2 | |
170 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
171 | #endif | |
172 | #ifdef SSL_OP_NO_SSLv3 | |
173 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
174 | #endif | |
175 | #ifdef SSL_OP_NO_TICKET | |
176 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
177 | #endif | |
178 | #ifdef SSL_OP_NO_TLSv1 | |
179 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
180 | #endif | |
181 | #ifdef SSL_OP_NO_TLSv1_1 | |
182 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
183 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
184 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
185 | #else | |
186 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
187 | #endif | |
188 | #endif | |
189 | #ifdef SSL_OP_NO_TLSv1_2 | |
190 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
191 | #endif | |
192 | #ifdef SSL_OP_NO_TLSv1_3 | |
193 | { US"no_tlsv1_3", SSL_OP_NO_TLSv1_3 }, | |
194 | #endif | |
195 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG | |
196 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
197 | #endif | |
198 | #ifdef SSL_OP_SINGLE_DH_USE | |
199 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, | |
200 | #endif | |
201 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
202 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, | |
203 | #endif | |
204 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
205 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, | |
206 | #endif | |
207 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
208 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, | |
209 | #endif | |
210 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
211 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, | |
212 | #endif | |
213 | #ifdef SSL_OP_TLS_D5_BUG | |
214 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, | |
215 | #endif | |
216 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
217 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, | |
218 | #endif | |
219 | }; | |
220 | ||
221 | #ifndef MACRO_PREDEF | |
222 | static int exim_openssl_options_size = nelem(exim_openssl_options); | |
223 | #endif | |
224 | ||
225 | #ifdef MACRO_PREDEF | |
226 | void | |
227 | options_tls(void) | |
228 | { | |
8442641e JH |
229 | uschar buf[64]; |
230 | ||
d7978c0f | 231 | for (struct exim_openssl_option * o = exim_openssl_options; |
8442641e JH |
232 | o < exim_openssl_options + nelem(exim_openssl_options); o++) |
233 | { | |
234 | /* Trailing X is workaround for problem with _OPT_OPENSSL_NO_TLSV1 | |
235 | being a ".ifdef _OPT_OPENSSL_NO_TLSV1_3" match */ | |
236 | ||
237 | spf(buf, sizeof(buf), US"_OPT_OPENSSL_%T_X", o->name); | |
238 | builtin_macro_create(buf); | |
239 | } | |
240 | } | |
241 | #else | |
242 | ||
243 | /******************************************************************************/ | |
244 | ||
059ec3d9 PH |
245 | /* Structure for collecting random data for seeding. */ |
246 | ||
247 | typedef struct randstuff { | |
9e3331ea TK |
248 | struct timeval tv; |
249 | pid_t p; | |
059ec3d9 PH |
250 | } randstuff; |
251 | ||
252 | /* Local static variables */ | |
253 | ||
a2ff477a JH |
254 | static BOOL client_verify_callback_called = FALSE; |
255 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
256 | static const uschar *sid_ctx = US"exim"; |
257 | ||
d4f09789 PP |
258 | /* We have three different contexts to care about. |
259 | ||
260 | Simple case: client, `client_ctx` | |
261 | As a client, we can be doing a callout or cut-through delivery while receiving | |
262 | a message. So we have a client context, which should have options initialised | |
74f1a423 JH |
263 | from the SMTP Transport. We may also concurrently want to make TLS connections |
264 | to utility daemons, so client-contexts are allocated and passed around in call | |
265 | args rather than using a gobal. | |
d4f09789 PP |
266 | |
267 | Server: | |
268 | There are two cases: with and without ServerNameIndication from the client. | |
269 | Given TLS SNI, we can be using different keys, certs and various other | |
270 | configuration settings, because they're re-expanded with $tls_sni set. This | |
271 | allows vhosting with TLS. This SNI is sent in the handshake. | |
272 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
273 | So as a server, we start out using `server_ctx`. | |
274 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
275 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
276 | configuration. | |
277 | */ | |
278 | ||
74f1a423 JH |
279 | typedef struct { |
280 | SSL_CTX * ctx; | |
281 | SSL * ssl; | |
282 | } exim_openssl_client_tls_ctx; | |
283 | ||
817d9f57 | 284 | static SSL_CTX *server_ctx = NULL; |
817d9f57 | 285 | static SSL *server_ssl = NULL; |
389ca47a | 286 | |
35731706 | 287 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 288 | static SSL_CTX *server_sni = NULL; |
35731706 | 289 | #endif |
059ec3d9 PH |
290 | |
291 | static char ssl_errstring[256]; | |
292 | ||
293 | static int ssl_session_timeout = 200; | |
a2ff477a JH |
294 | static BOOL client_verify_optional = FALSE; |
295 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 296 | |
f5d78688 | 297 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
298 | |
299 | ||
7be682ca PP |
300 | typedef struct tls_ext_ctx_cb { |
301 | uschar *certificate; | |
302 | uschar *privatekey; | |
f5d78688 | 303 | BOOL is_server; |
a6510420 | 304 | #ifndef DISABLE_OCSP |
c3033f13 | 305 | STACK_OF(X509) *verify_stack; /* chain for verifying the proof */ |
f5d78688 JH |
306 | union { |
307 | struct { | |
308 | uschar *file; | |
309 | uschar *file_expanded; | |
310 | OCSP_RESPONSE *response; | |
311 | } server; | |
312 | struct { | |
44662487 JH |
313 | X509_STORE *verify_store; /* non-null if status requested */ |
314 | BOOL verify_required; | |
f5d78688 JH |
315 | } client; |
316 | } u_ocsp; | |
3f7eeb86 | 317 | #endif |
7be682ca PP |
318 | uschar *dhparam; |
319 | /* these are cached from first expand */ | |
320 | uschar *server_cipher_list; | |
321 | /* only passed down to tls_error: */ | |
322 | host_item *host; | |
55414b25 | 323 | const uschar * verify_cert_hostnames; |
0cbf2b82 | 324 | #ifndef DISABLE_EVENT |
a7538db1 JH |
325 | uschar * event_action; |
326 | #endif | |
7be682ca PP |
327 | } tls_ext_ctx_cb; |
328 | ||
329 | /* should figure out a cleanup of API to handle state preserved per | |
330 | implementation, for various reasons, which can be void * in the APIs. | |
331 | For now, we hack around it. */ | |
817d9f57 JH |
332 | tls_ext_ctx_cb *client_static_cbinfo = NULL; |
333 | tls_ext_ctx_cb *server_static_cbinfo = NULL; | |
7be682ca PP |
334 | |
335 | static int | |
983207c1 | 336 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 337 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr ); |
059ec3d9 | 338 | |
3f7eeb86 | 339 | /* Callbacks */ |
3bcbbbe2 | 340 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 341 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 342 | #endif |
f2de3a33 | 343 | #ifndef DISABLE_OCSP |
f5d78688 | 344 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
345 | #endif |
346 | ||
059ec3d9 PH |
347 | |
348 | /************************************************* | |
349 | * Handle TLS error * | |
350 | *************************************************/ | |
351 | ||
352 | /* Called from lots of places when errors occur before actually starting to do | |
353 | the TLS handshake, that is, while the session is still in clear. Always returns | |
354 | DEFER for a server and FAIL for a client so that most calls can use "return | |
355 | tls_error(...)" to do this processing and then give an appropriate return. A | |
356 | single function is used for both server and client, because it is called from | |
357 | some shared functions. | |
358 | ||
359 | Argument: | |
360 | prefix text to include in the logged error | |
361 | host NULL if setting up a server; | |
362 | the connected host if setting up a client | |
7199e1ee | 363 | msg error message or NULL if we should ask OpenSSL |
cf0c6164 | 364 | errstr pointer to output error message |
059ec3d9 PH |
365 | |
366 | Returns: OK/DEFER/FAIL | |
367 | */ | |
368 | ||
369 | static int | |
cf0c6164 | 370 | tls_error(uschar * prefix, const host_item * host, uschar * msg, uschar ** errstr) |
059ec3d9 | 371 | { |
c562fd30 | 372 | if (!msg) |
7199e1ee | 373 | { |
0abc5a13 | 374 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 | 375 | msg = US ssl_errstring; |
7199e1ee TF |
376 | } |
377 | ||
5a2a0989 JH |
378 | msg = string_sprintf("(%s): %s", prefix, msg); |
379 | DEBUG(D_tls) debug_printf("TLS error '%s'\n", msg); | |
380 | if (errstr) *errstr = msg; | |
cf0c6164 | 381 | return host ? FAIL : DEFER; |
059ec3d9 PH |
382 | } |
383 | ||
384 | ||
385 | ||
386 | /************************************************* | |
387 | * Callback to generate RSA key * | |
388 | *************************************************/ | |
389 | ||
390 | /* | |
391 | Arguments: | |
3ae79556 | 392 | s SSL connection (not used) |
059ec3d9 PH |
393 | export not used |
394 | keylength keylength | |
395 | ||
396 | Returns: pointer to generated key | |
397 | */ | |
398 | ||
399 | static RSA * | |
400 | rsa_callback(SSL *s, int export, int keylength) | |
401 | { | |
402 | RSA *rsa_key; | |
c8dfb21d JH |
403 | #ifdef EXIM_HAVE_RSA_GENKEY_EX |
404 | BIGNUM *bn = BN_new(); | |
405 | #endif | |
406 | ||
059ec3d9 PH |
407 | export = export; /* Shut picky compilers up */ |
408 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
c8dfb21d JH |
409 | |
410 | #ifdef EXIM_HAVE_RSA_GENKEY_EX | |
411 | if ( !BN_set_word(bn, (unsigned long)RSA_F4) | |
f2cb6292 | 412 | || !(rsa_key = RSA_new()) |
c8dfb21d JH |
413 | || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL) |
414 | ) | |
415 | #else | |
23bb6982 | 416 | if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL))) |
c8dfb21d JH |
417 | #endif |
418 | ||
059ec3d9 | 419 | { |
0abc5a13 | 420 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
059ec3d9 PH |
421 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", |
422 | ssl_errstring); | |
423 | return NULL; | |
424 | } | |
425 | return rsa_key; | |
426 | } | |
427 | ||
428 | ||
429 | ||
f5d78688 | 430 | /* Extreme debug |
f2de3a33 | 431 | #ifndef DISABLE_OCSP |
f5d78688 JH |
432 | void |
433 | x509_store_dump_cert_s_names(X509_STORE * store) | |
434 | { | |
435 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
f5d78688 JH |
436 | static uschar name[256]; |
437 | ||
d7978c0f | 438 | for (int i= 0; i < sk_X509_OBJECT_num(roots); i++) |
f5d78688 JH |
439 | { |
440 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
441 | if(tmp_obj->type == X509_LU_X509) | |
442 | { | |
70e384dd JH |
443 | X509_NAME * sn = X509_get_subject_name(tmp_obj->data.x509); |
444 | if (X509_NAME_oneline(sn, CS name, sizeof(name))) | |
445 | { | |
446 | name[sizeof(name)-1] = '\0'; | |
447 | debug_printf(" %s\n", name); | |
448 | } | |
f5d78688 JH |
449 | } |
450 | } | |
451 | } | |
452 | #endif | |
453 | */ | |
454 | ||
059ec3d9 | 455 | |
0cbf2b82 | 456 | #ifndef DISABLE_EVENT |
f69979cf JH |
457 | static int |
458 | verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn, | |
459 | BOOL *calledp, const BOOL *optionalp, const uschar * what) | |
460 | { | |
461 | uschar * ev; | |
462 | uschar * yield; | |
463 | X509 * old_cert; | |
464 | ||
465 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; | |
466 | if (ev) | |
467 | { | |
aaba7d03 | 468 | DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth); |
f69979cf JH |
469 | old_cert = tlsp->peercert; |
470 | tlsp->peercert = X509_dup(cert); | |
471 | /* NB we do not bother setting peerdn */ | |
472 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) | |
473 | { | |
474 | log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: " | |
475 | "depth=%d cert=%s: %s", | |
476 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
477 | what, depth, dn, yield); | |
478 | *calledp = TRUE; | |
479 | if (!*optionalp) | |
480 | { | |
481 | if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */ | |
482 | return 1; /* reject (leaving peercert set) */ | |
483 | } | |
484 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
485 | "(host in tls_try_verify_hosts)\n"); | |
486 | } | |
487 | X509_free(tlsp->peercert); | |
488 | tlsp->peercert = old_cert; | |
489 | } | |
490 | return 0; | |
491 | } | |
492 | #endif | |
493 | ||
059ec3d9 PH |
494 | /************************************************* |
495 | * Callback for verification * | |
496 | *************************************************/ | |
497 | ||
498 | /* The SSL library does certificate verification if set up to do so. This | |
499 | callback has the current yes/no state is in "state". If verification succeeded, | |
f69979cf JH |
500 | we set the certificate-verified flag. If verification failed, what happens |
501 | depends on whether the client is required to present a verifiable certificate | |
502 | or not. | |
059ec3d9 PH |
503 | |
504 | If verification is optional, we change the state to yes, but still log the | |
505 | verification error. For some reason (it really would help to have proper | |
506 | documentation of OpenSSL), this callback function then gets called again, this | |
f69979cf JH |
507 | time with state = 1. We must take care not to set the private verified flag on |
508 | the second time through. | |
059ec3d9 PH |
509 | |
510 | Note: this function is not called if the client fails to present a certificate | |
511 | when asked. We get here only if a certificate has been received. Handling of | |
512 | optional verification for this case is done when requesting SSL to verify, by | |
513 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
514 | ||
a7538db1 JH |
515 | May be called multiple times for different issues with a certificate, even |
516 | for a given "depth" in the certificate chain. | |
517 | ||
059ec3d9 | 518 | Arguments: |
f2f2c91b JH |
519 | preverify_ok current yes/no state as 1/0 |
520 | x509ctx certificate information. | |
521 | tlsp per-direction (client vs. server) support data | |
522 | calledp has-been-called flag | |
523 | optionalp verification-is-optional flag | |
059ec3d9 | 524 | |
f2f2c91b | 525 | Returns: 0 if verification should fail, otherwise 1 |
059ec3d9 PH |
526 | */ |
527 | ||
528 | static int | |
70e384dd JH |
529 | verify_callback(int preverify_ok, X509_STORE_CTX * x509ctx, |
530 | tls_support * tlsp, BOOL * calledp, BOOL * optionalp) | |
059ec3d9 | 531 | { |
421aff85 | 532 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 533 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 534 | uschar dn[256]; |
059ec3d9 | 535 | |
70e384dd JH |
536 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
537 | { | |
538 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
539 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
540 | tlsp == &tls_out ? deliver_host_address : sender_host_address); | |
541 | return 0; | |
542 | } | |
f69979cf | 543 | dn[sizeof(dn)-1] = '\0'; |
059ec3d9 | 544 | |
f2f2c91b | 545 | if (preverify_ok == 0) |
059ec3d9 | 546 | { |
f77197ae JH |
547 | uschar * extra = verify_mode ? string_sprintf(" (during %c-verify for [%s])", |
548 | *verify_mode, sender_host_address) | |
549 | : US""; | |
550 | log_write(0, LOG_MAIN, "[%s] SSL verify error%s: depth=%d error=%s cert=%s", | |
551 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
552 | extra, depth, | |
553 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), dn); | |
a2ff477a | 554 | *calledp = TRUE; |
9d1c15ef JH |
555 | if (!*optionalp) |
556 | { | |
f69979cf JH |
557 | if (!tlsp->peercert) |
558 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
559 | return 0; /* reject */ | |
9d1c15ef | 560 | } |
059ec3d9 PH |
561 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
562 | "tls_try_verify_hosts)\n"); | |
059ec3d9 PH |
563 | } |
564 | ||
a7538db1 | 565 | else if (depth != 0) |
059ec3d9 | 566 | { |
f69979cf | 567 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn); |
f2de3a33 | 568 | #ifndef DISABLE_OCSP |
f5d78688 JH |
569 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
570 | { /* client, wanting stapling */ | |
571 | /* Add the server cert's signing chain as the one | |
572 | for the verification of the OCSP stapled information. */ | |
94431adb | 573 | |
f5d78688 | 574 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, |
421aff85 | 575 | cert)) |
f5d78688 | 576 | ERR_clear_error(); |
c3033f13 | 577 | sk_X509_push(client_static_cbinfo->verify_stack, cert); |
f5d78688 | 578 | } |
a7538db1 | 579 | #endif |
0cbf2b82 | 580 | #ifndef DISABLE_EVENT |
f69979cf JH |
581 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
582 | return 0; /* reject, with peercert set */ | |
f5d78688 | 583 | #endif |
059ec3d9 PH |
584 | } |
585 | else | |
586 | { | |
55414b25 | 587 | const uschar * verify_cert_hostnames; |
e51c7be2 | 588 | |
e51c7be2 JH |
589 | if ( tlsp == &tls_out |
590 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
afdb5e9c | 591 | /* client, wanting hostname check */ |
e51c7be2 | 592 | { |
f69979cf | 593 | |
740f36d4 | 594 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
f69979cf JH |
595 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
596 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
597 | # endif | |
598 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
599 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
600 | # endif | |
e51c7be2 | 601 | int sep = 0; |
55414b25 | 602 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 603 | uschar * name; |
d8e7834a JH |
604 | int rc; |
605 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
f40d5be3 | 606 | if ((rc = X509_check_host(cert, CCS name, 0, |
8d692470 | 607 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
740f36d4 JH |
608 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS, |
609 | NULL))) | |
d8e7834a JH |
610 | { |
611 | if (rc < 0) | |
612 | { | |
93a6fce2 | 613 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
f77197ae | 614 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
615 | name = NULL; |
616 | } | |
e51c7be2 | 617 | break; |
d8e7834a | 618 | } |
e51c7be2 | 619 | if (!name) |
f69979cf | 620 | #else |
e51c7be2 | 621 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) |
f69979cf | 622 | #endif |
e51c7be2 | 623 | { |
f77197ae JH |
624 | uschar * extra = verify_mode |
625 | ? string_sprintf(" (during %c-verify for [%s])", | |
626 | *verify_mode, sender_host_address) | |
627 | : US""; | |
e51c7be2 | 628 | log_write(0, LOG_MAIN, |
f77197ae JH |
629 | "[%s] SSL verify error%s: certificate name mismatch: DN=\"%s\" H=\"%s\"", |
630 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
631 | extra, dn, verify_cert_hostnames); | |
a3ef7310 JH |
632 | *calledp = TRUE; |
633 | if (!*optionalp) | |
f69979cf JH |
634 | { |
635 | if (!tlsp->peercert) | |
636 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
637 | return 0; /* reject */ | |
638 | } | |
a3ef7310 JH |
639 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
640 | "tls_try_verify_hosts)\n"); | |
e51c7be2 | 641 | } |
f69979cf | 642 | } |
e51c7be2 | 643 | |
0cbf2b82 | 644 | #ifndef DISABLE_EVENT |
f69979cf JH |
645 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
646 | return 0; /* reject, with peercert set */ | |
e51c7be2 JH |
647 | #endif |
648 | ||
93dcb1c2 | 649 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
f69979cf | 650 | *calledp ? "" : " authenticated", dn); |
93dcb1c2 JH |
651 | if (!*calledp) tlsp->certificate_verified = TRUE; |
652 | *calledp = TRUE; | |
059ec3d9 PH |
653 | } |
654 | ||
a7538db1 | 655 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
656 | } |
657 | ||
a2ff477a | 658 | static int |
f2f2c91b | 659 | verify_callback_client(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 660 | { |
f2f2c91b JH |
661 | return verify_callback(preverify_ok, x509ctx, &tls_out, |
662 | &client_verify_callback_called, &client_verify_optional); | |
a2ff477a JH |
663 | } |
664 | ||
665 | static int | |
f2f2c91b | 666 | verify_callback_server(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 667 | { |
f2f2c91b JH |
668 | return verify_callback(preverify_ok, x509ctx, &tls_in, |
669 | &server_verify_callback_called, &server_verify_optional); | |
a2ff477a JH |
670 | } |
671 | ||
059ec3d9 | 672 | |
c0635b6d | 673 | #ifdef SUPPORT_DANE |
53a7196b | 674 | |
e5cccda9 JH |
675 | /* This gets called *by* the dane library verify callback, which interposes |
676 | itself. | |
677 | */ | |
678 | static int | |
f2f2c91b | 679 | verify_callback_client_dane(int preverify_ok, X509_STORE_CTX * x509ctx) |
e5cccda9 JH |
680 | { |
681 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
f69979cf | 682 | uschar dn[256]; |
83b27293 | 683 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
5c75db2e | 684 | #ifndef DISABLE_EVENT |
f69979cf | 685 | BOOL dummy_called, optional = FALSE; |
83b27293 | 686 | #endif |
e5cccda9 | 687 | |
70e384dd JH |
688 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
689 | { | |
690 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
691 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
692 | deliver_host_address); | |
693 | return 0; | |
694 | } | |
f69979cf | 695 | dn[sizeof(dn)-1] = '\0'; |
e5cccda9 | 696 | |
f2f2c91b JH |
697 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s depth %d %s\n", |
698 | preverify_ok ? "ok":"BAD", depth, dn); | |
e5cccda9 | 699 | |
0cbf2b82 | 700 | #ifndef DISABLE_EVENT |
f69979cf JH |
701 | if (verify_event(&tls_out, cert, depth, dn, |
702 | &dummy_called, &optional, US"DANE")) | |
703 | return 0; /* reject, with peercert set */ | |
83b27293 JH |
704 | #endif |
705 | ||
f2f2c91b | 706 | if (preverify_ok == 1) |
6fbf3599 JH |
707 | { |
708 | tls_out.dane_verified = tls_out.certificate_verified = TRUE; | |
709 | #ifndef DISABLE_OCSP | |
710 | if (client_static_cbinfo->u_ocsp.client.verify_store) | |
711 | { /* client, wanting stapling */ | |
712 | /* Add the server cert's signing chain as the one | |
713 | for the verification of the OCSP stapled information. */ | |
714 | ||
715 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
716 | cert)) | |
717 | ERR_clear_error(); | |
718 | sk_X509_push(client_static_cbinfo->verify_stack, cert); | |
719 | } | |
720 | #endif | |
721 | } | |
f2f2c91b JH |
722 | else |
723 | { | |
724 | int err = X509_STORE_CTX_get_error(x509ctx); | |
725 | DEBUG(D_tls) | |
726 | debug_printf(" - err %d '%s'\n", err, X509_verify_cert_error_string(err)); | |
3c51463e | 727 | if (err == X509_V_ERR_APPLICATION_VERIFICATION) |
f2f2c91b JH |
728 | preverify_ok = 1; |
729 | } | |
730 | return preverify_ok; | |
e5cccda9 | 731 | } |
53a7196b | 732 | |
c0635b6d | 733 | #endif /*SUPPORT_DANE*/ |
e5cccda9 | 734 | |
059ec3d9 PH |
735 | |
736 | /************************************************* | |
737 | * Information callback * | |
738 | *************************************************/ | |
739 | ||
740 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
741 | are doing. We copy the string to the debugging output when TLS debugging has |
742 | been requested. | |
059ec3d9 PH |
743 | |
744 | Arguments: | |
745 | s the SSL connection | |
746 | where | |
747 | ret | |
748 | ||
749 | Returns: nothing | |
750 | */ | |
751 | ||
752 | static void | |
753 | info_callback(SSL *s, int where, int ret) | |
754 | { | |
0abc5a13 JH |
755 | DEBUG(D_tls) |
756 | { | |
757 | const uschar * str; | |
758 | ||
759 | if (where & SSL_ST_CONNECT) | |
48224640 | 760 | str = US"SSL_connect"; |
0abc5a13 | 761 | else if (where & SSL_ST_ACCEPT) |
48224640 | 762 | str = US"SSL_accept"; |
0abc5a13 | 763 | else |
48224640 | 764 | str = US"SSL info (undefined)"; |
0abc5a13 JH |
765 | |
766 | if (where & SSL_CB_LOOP) | |
767 | debug_printf("%s: %s\n", str, SSL_state_string_long(s)); | |
768 | else if (where & SSL_CB_ALERT) | |
769 | debug_printf("SSL3 alert %s:%s:%s\n", | |
48224640 | 770 | str = where & SSL_CB_READ ? US"read" : US"write", |
0abc5a13 JH |
771 | SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret)); |
772 | else if (where & SSL_CB_EXIT) | |
773 | if (ret == 0) | |
774 | debug_printf("%s: failed in %s\n", str, SSL_state_string_long(s)); | |
775 | else if (ret < 0) | |
776 | debug_printf("%s: error in %s\n", str, SSL_state_string_long(s)); | |
777 | else if (where & SSL_CB_HANDSHAKE_START) | |
778 | debug_printf("%s: hshake start: %s\n", str, SSL_state_string_long(s)); | |
779 | else if (where & SSL_CB_HANDSHAKE_DONE) | |
780 | debug_printf("%s: hshake done: %s\n", str, SSL_state_string_long(s)); | |
781 | } | |
059ec3d9 PH |
782 | } |
783 | ||
8a40db1c JH |
784 | static void |
785 | keylog_callback(const SSL *ssl, const char *line) | |
786 | { | |
787 | DEBUG(D_tls) debug_printf("%.200s\n", line); | |
788 | } | |
789 | ||
059ec3d9 PH |
790 | |
791 | ||
792 | /************************************************* | |
793 | * Initialize for DH * | |
794 | *************************************************/ | |
795 | ||
796 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
797 | ||
798 | Arguments: | |
038597d2 | 799 | sctx The current SSL CTX (inbound or outbound) |
a799883d | 800 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 801 | host connected host, if client; NULL if server |
cf0c6164 | 802 | errstr error string pointer |
059ec3d9 PH |
803 | |
804 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
805 | */ | |
806 | ||
807 | static BOOL | |
cf0c6164 | 808 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr) |
059ec3d9 | 809 | { |
059ec3d9 PH |
810 | BIO *bio; |
811 | DH *dh; | |
812 | uschar *dhexpanded; | |
a799883d | 813 | const char *pem; |
6600985a | 814 | int dh_bitsize; |
059ec3d9 | 815 | |
cf0c6164 | 816 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr)) |
059ec3d9 PH |
817 | return FALSE; |
818 | ||
0df4ab80 | 819 | if (!dhexpanded || !*dhexpanded) |
a799883d | 820 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 821 | else if (dhexpanded[0] == '/') |
059ec3d9 | 822 | { |
0df4ab80 | 823 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 824 | { |
7199e1ee | 825 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
cf0c6164 | 826 | host, US strerror(errno), errstr); |
a799883d | 827 | return FALSE; |
059ec3d9 | 828 | } |
a799883d PP |
829 | } |
830 | else | |
831 | { | |
832 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 833 | { |
a799883d PP |
834 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
835 | return TRUE; | |
059ec3d9 | 836 | } |
a799883d | 837 | |
0df4ab80 | 838 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
839 | { |
840 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
cf0c6164 | 841 | host, US strerror(errno), errstr); |
a799883d PP |
842 | return FALSE; |
843 | } | |
844 | bio = BIO_new_mem_buf(CS pem, -1); | |
845 | } | |
846 | ||
0df4ab80 | 847 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 848 | { |
059ec3d9 | 849 | BIO_free(bio); |
a799883d | 850 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
cf0c6164 | 851 | host, NULL, errstr); |
a799883d PP |
852 | return FALSE; |
853 | } | |
854 | ||
6600985a PP |
855 | /* note: our default limit of 2236 is not a multiple of 8; the limit comes from |
856 | * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with | |
857 | * 2236. But older OpenSSL can only report in bytes (octets), not bits. | |
858 | * If someone wants to dance at the edge, then they can raise the limit or use | |
859 | * current libraries. */ | |
860 | #ifdef EXIM_HAVE_OPENSSL_DH_BITS | |
861 | /* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022 | |
862 | * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */ | |
863 | dh_bitsize = DH_bits(dh); | |
864 | #else | |
865 | dh_bitsize = 8 * DH_size(dh); | |
866 | #endif | |
867 | ||
a799883d PP |
868 | /* Even if it is larger, we silently return success rather than cause things |
869 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
870 | * debatable choice. */ | |
6600985a | 871 | if (dh_bitsize > tls_dh_max_bits) |
a799883d PP |
872 | { |
873 | DEBUG(D_tls) | |
170f4904 | 874 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n", |
6600985a | 875 | dh_bitsize, tls_dh_max_bits); |
a799883d PP |
876 | } |
877 | else | |
878 | { | |
879 | SSL_CTX_set_tmp_dh(sctx, dh); | |
880 | DEBUG(D_tls) | |
881 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
6600985a | 882 | dhexpanded ? dhexpanded : US"default", dh_bitsize); |
059ec3d9 PH |
883 | } |
884 | ||
a799883d PP |
885 | DH_free(dh); |
886 | BIO_free(bio); | |
887 | ||
888 | return TRUE; | |
059ec3d9 PH |
889 | } |
890 | ||
891 | ||
892 | ||
893 | ||
038597d2 PP |
894 | /************************************************* |
895 | * Initialize for ECDH * | |
896 | *************************************************/ | |
897 | ||
898 | /* Load parameters for ECDH encryption. | |
899 | ||
900 | For now, we stick to NIST P-256 because: it's simple and easy to configure; | |
901 | it avoids any patent issues that might bite redistributors; despite events in | |
902 | the news and concerns over curve choices, we're not cryptographers, we're not | |
903 | pretending to be, and this is "good enough" to be better than no support, | |
904 | protecting against most adversaries. Given another year or two, there might | |
905 | be sufficient clarity about a "right" way forward to let us make an informed | |
906 | decision, instead of a knee-jerk reaction. | |
907 | ||
908 | Longer-term, we should look at supporting both various named curves and | |
909 | external files generated with "openssl ecparam", much as we do for init_dh(). | |
910 | We should also support "none" as a value, to explicitly avoid initialisation. | |
911 | ||
912 | Patches welcome. | |
913 | ||
914 | Arguments: | |
915 | sctx The current SSL CTX (inbound or outbound) | |
916 | host connected host, if client; NULL if server | |
cf0c6164 | 917 | errstr error string pointer |
038597d2 PP |
918 | |
919 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
920 | */ | |
921 | ||
922 | static BOOL | |
cf0c6164 | 923 | init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr) |
038597d2 | 924 | { |
63f0dbe0 JH |
925 | #ifdef OPENSSL_NO_ECDH |
926 | return TRUE; | |
927 | #else | |
928 | ||
10ca4f1c JH |
929 | EC_KEY * ecdh; |
930 | uschar * exp_curve; | |
931 | int nid; | |
932 | BOOL rv; | |
933 | ||
038597d2 PP |
934 | if (host) /* No ECDH setup for clients, only for servers */ |
935 | return TRUE; | |
936 | ||
10ca4f1c | 937 | # ifndef EXIM_HAVE_ECDH |
038597d2 PP |
938 | DEBUG(D_tls) |
939 | debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); | |
940 | return TRUE; | |
038597d2 | 941 | # else |
10ca4f1c | 942 | |
cf0c6164 | 943 | if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr)) |
10ca4f1c JH |
944 | return FALSE; |
945 | if (!exp_curve || !*exp_curve) | |
946 | return TRUE; | |
947 | ||
8e53a4fc | 948 | /* "auto" needs to be handled carefully. |
4c04137d | 949 | * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1 |
8e53a4fc | 950 | * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto |
4c04137d | 951 | * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO) |
8e53a4fc HSHR |
952 | * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection |
953 | * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b | |
954 | */ | |
10ca4f1c | 955 | if (Ustrcmp(exp_curve, "auto") == 0) |
038597d2 | 956 | { |
8e53a4fc | 957 | #if OPENSSL_VERSION_NUMBER < 0x10002000L |
10ca4f1c | 958 | DEBUG(D_tls) debug_printf( |
8e53a4fc | 959 | "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n"); |
78a3bbd5 | 960 | exp_curve = US"prime256v1"; |
8e53a4fc HSHR |
961 | #else |
962 | # if defined SSL_CTRL_SET_ECDH_AUTO | |
963 | DEBUG(D_tls) debug_printf( | |
964 | "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n"); | |
10ca4f1c JH |
965 | SSL_CTX_set_ecdh_auto(sctx, 1); |
966 | return TRUE; | |
8e53a4fc HSHR |
967 | # else |
968 | DEBUG(D_tls) debug_printf( | |
969 | "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n"); | |
970 | return TRUE; | |
971 | # endif | |
972 | #endif | |
10ca4f1c | 973 | } |
038597d2 | 974 | |
10ca4f1c JH |
975 | DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve); |
976 | if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef | |
977 | # ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID | |
978 | && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef | |
979 | # endif | |
980 | ) | |
981 | { | |
cf0c6164 JH |
982 | tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve), |
983 | host, NULL, errstr); | |
10ca4f1c JH |
984 | return FALSE; |
985 | } | |
038597d2 | 986 | |
10ca4f1c JH |
987 | if (!(ecdh = EC_KEY_new_by_curve_name(nid))) |
988 | { | |
cf0c6164 | 989 | tls_error(US"Unable to create ec curve", host, NULL, errstr); |
10ca4f1c | 990 | return FALSE; |
038597d2 | 991 | } |
10ca4f1c JH |
992 | |
993 | /* The "tmp" in the name here refers to setting a temporary key | |
994 | not to the stability of the interface. */ | |
995 | ||
996 | if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) | |
cf0c6164 | 997 | tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr); |
10ca4f1c JH |
998 | else |
999 | DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); | |
1000 | ||
1001 | EC_KEY_free(ecdh); | |
1002 | return !rv; | |
1003 | ||
1004 | # endif /*EXIM_HAVE_ECDH*/ | |
1005 | #endif /*OPENSSL_NO_ECDH*/ | |
038597d2 PP |
1006 | } |
1007 | ||
1008 | ||
1009 | ||
1010 | ||
f2de3a33 | 1011 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1012 | /************************************************* |
1013 | * Load OCSP information into state * | |
1014 | *************************************************/ | |
f5d78688 | 1015 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
1016 | caller has determined this is needed. Checks validity. Debugs a message |
1017 | if invalid. | |
1018 | ||
1019 | ASSUMES: single response, for single cert. | |
1020 | ||
1021 | Arguments: | |
1022 | sctx the SSL_CTX* to update | |
1023 | cbinfo various parts of session state | |
1024 | expanded the filename putatively holding an OCSP response | |
1025 | ||
1026 | */ | |
1027 | ||
1028 | static void | |
f5d78688 | 1029 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 | 1030 | { |
ee5b1e28 JH |
1031 | BIO * bio; |
1032 | OCSP_RESPONSE * resp; | |
1033 | OCSP_BASICRESP * basic_response; | |
1034 | OCSP_SINGLERESP * single_response; | |
1035 | ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd; | |
ee5b1e28 | 1036 | STACK_OF(X509) * sk; |
3f7eeb86 PP |
1037 | unsigned long verify_flags; |
1038 | int status, reason, i; | |
1039 | ||
f5d78688 JH |
1040 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
1041 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 1042 | { |
f5d78688 JH |
1043 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
1044 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
1045 | } |
1046 | ||
ee5b1e28 | 1047 | if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"))) |
3f7eeb86 PP |
1048 | { |
1049 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 1050 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
1051 | return; |
1052 | } | |
1053 | ||
1054 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
1055 | BIO_free(bio); | |
1056 | if (!resp) | |
1057 | { | |
1058 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
1059 | return; | |
1060 | } | |
1061 | ||
ee5b1e28 | 1062 | if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL) |
3f7eeb86 PP |
1063 | { |
1064 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
1065 | OCSP_response_status_str(status), status); | |
f5d78688 | 1066 | goto bad; |
3f7eeb86 PP |
1067 | } |
1068 | ||
ee5b1e28 | 1069 | if (!(basic_response = OCSP_response_get1_basic(resp))) |
3f7eeb86 PP |
1070 | { |
1071 | DEBUG(D_tls) | |
1072 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 1073 | goto bad; |
3f7eeb86 PP |
1074 | } |
1075 | ||
c3033f13 | 1076 | sk = cbinfo->verify_stack; |
3f7eeb86 PP |
1077 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ |
1078 | ||
1079 | /* May need to expose ability to adjust those flags? | |
1080 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
1081 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
1082 | ||
4c04137d | 1083 | /* This does a full verify on the OCSP proof before we load it for serving |
ee5b1e28 JH |
1084 | up; possibly overkill - just date-checks might be nice enough. |
1085 | ||
1086 | OCSP_basic_verify takes a "store" arg, but does not | |
1087 | use it for the chain verification, which is all we do | |
1088 | when OCSP_NOVERIFY is set. The content from the wire | |
1089 | "basic_response" and a cert-stack "sk" are all that is used. | |
1090 | ||
c3033f13 JH |
1091 | We have a stack, loaded in setup_certs() if tls_verify_certificates |
1092 | was a file (not a directory, or "system"). It is unfortunate we | |
1093 | cannot used the connection context store, as that would neatly | |
1094 | handle the "system" case too, but there seems to be no library | |
1095 | function for getting a stack from a store. | |
e3555426 | 1096 | [ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ] |
c3033f13 JH |
1097 | We do not free the stack since it could be needed a second time for |
1098 | SNI handling. | |
1099 | ||
4c04137d | 1100 | Separately we might try to replace using OCSP_basic_verify() - which seems to not |
5ec37a55 | 1101 | be a public interface into the OpenSSL library (there's no manual entry) - |
ee5b1e28 | 1102 | But what with? We also use OCSP_basic_verify in the client stapling callback. |
4c04137d | 1103 | And there we NEED it; we must verify that status... unless the |
ee5b1e28 JH |
1104 | library does it for us anyway? */ |
1105 | ||
1106 | if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0) | |
3f7eeb86 | 1107 | { |
ee5b1e28 JH |
1108 | DEBUG(D_tls) |
1109 | { | |
0abc5a13 | 1110 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3f7eeb86 | 1111 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); |
f5d78688 JH |
1112 | } |
1113 | goto bad; | |
3f7eeb86 PP |
1114 | } |
1115 | ||
1116 | /* Here's the simplifying assumption: there's only one response, for the | |
1117 | one certificate we use, and nothing for anything else in a chain. If this | |
1118 | proves false, we need to extract a cert id from our issued cert | |
1119 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
1120 | right cert in the stack and then calls OCSP_single_get0_status()). | |
1121 | ||
1122 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
ee5b1e28 JH |
1123 | |
1124 | if (!(single_response = OCSP_resp_get0(basic_response, 0))) | |
3f7eeb86 PP |
1125 | { |
1126 | DEBUG(D_tls) | |
1127 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 1128 | goto bad; |
3f7eeb86 PP |
1129 | } |
1130 | ||
1131 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 1132 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 1133 | { |
f5d78688 JH |
1134 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
1135 | OCSP_cert_status_str(status), status, | |
1136 | OCSP_crl_reason_str(reason), reason); | |
1137 | goto bad; | |
3f7eeb86 PP |
1138 | } |
1139 | ||
1140 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
1141 | { | |
1142 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 1143 | goto bad; |
3f7eeb86 PP |
1144 | } |
1145 | ||
f5d78688 | 1146 | supply_response: |
47195144 | 1147 | cbinfo->u_ocsp.server.response = resp; /*XXX stack?*/ |
f5d78688 JH |
1148 | return; |
1149 | ||
1150 | bad: | |
8768d548 | 1151 | if (f.running_in_test_harness) |
018058b2 JH |
1152 | { |
1153 | extern char ** environ; | |
d7978c0f | 1154 | if (environ) for (uschar ** p = USS environ; *p; p++) |
018058b2 JH |
1155 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) |
1156 | { | |
1157 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
1158 | goto supply_response; | |
1159 | } | |
1160 | } | |
f5d78688 | 1161 | return; |
3f7eeb86 | 1162 | } |
f2de3a33 | 1163 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1164 | |
1165 | ||
1166 | ||
1167 | ||
23bb6982 JH |
1168 | /* Create and install a selfsigned certificate, for use in server mode */ |
1169 | ||
1170 | static int | |
cf0c6164 | 1171 | tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr) |
23bb6982 JH |
1172 | { |
1173 | X509 * x509 = NULL; | |
1174 | EVP_PKEY * pkey; | |
1175 | RSA * rsa; | |
1176 | X509_NAME * name; | |
1177 | uschar * where; | |
1178 | ||
1179 | where = US"allocating pkey"; | |
1180 | if (!(pkey = EVP_PKEY_new())) | |
1181 | goto err; | |
1182 | ||
1183 | where = US"allocating cert"; | |
1184 | if (!(x509 = X509_new())) | |
1185 | goto err; | |
1186 | ||
1187 | where = US"generating pkey"; | |
6aac3239 | 1188 | if (!(rsa = rsa_callback(NULL, 0, 2048))) |
23bb6982 JH |
1189 | goto err; |
1190 | ||
4c04137d | 1191 | where = US"assigning pkey"; |
23bb6982 JH |
1192 | if (!EVP_PKEY_assign_RSA(pkey, rsa)) |
1193 | goto err; | |
1194 | ||
1195 | X509_set_version(x509, 2); /* N+1 - version 3 */ | |
1613fd68 | 1196 | ASN1_INTEGER_set(X509_get_serialNumber(x509), 1); |
23bb6982 JH |
1197 | X509_gmtime_adj(X509_get_notBefore(x509), 0); |
1198 | X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60); /* 1 hour */ | |
1199 | X509_set_pubkey(x509, pkey); | |
1200 | ||
1201 | name = X509_get_subject_name(x509); | |
1202 | X509_NAME_add_entry_by_txt(name, "C", | |
4dc2379a | 1203 | MBSTRING_ASC, CUS "UK", -1, -1, 0); |
23bb6982 | 1204 | X509_NAME_add_entry_by_txt(name, "O", |
4dc2379a | 1205 | MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0); |
23bb6982 | 1206 | X509_NAME_add_entry_by_txt(name, "CN", |
4dc2379a | 1207 | MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0); |
23bb6982 JH |
1208 | X509_set_issuer_name(x509, name); |
1209 | ||
1210 | where = US"signing cert"; | |
1211 | if (!X509_sign(x509, pkey, EVP_md5())) | |
1212 | goto err; | |
1213 | ||
1214 | where = US"installing selfsign cert"; | |
1215 | if (!SSL_CTX_use_certificate(sctx, x509)) | |
1216 | goto err; | |
1217 | ||
1218 | where = US"installing selfsign key"; | |
1219 | if (!SSL_CTX_use_PrivateKey(sctx, pkey)) | |
1220 | goto err; | |
1221 | ||
1222 | return OK; | |
1223 | ||
1224 | err: | |
cf0c6164 | 1225 | (void) tls_error(where, NULL, NULL, errstr); |
23bb6982 JH |
1226 | if (x509) X509_free(x509); |
1227 | if (pkey) EVP_PKEY_free(pkey); | |
1228 | return DEFER; | |
1229 | } | |
1230 | ||
1231 | ||
1232 | ||
1233 | ||
ba86e143 JH |
1234 | static int |
1235 | tls_add_certfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1236 | uschar ** errstr) | |
1237 | { | |
1238 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", file); | |
1239 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS file)) | |
1240 | return tls_error(string_sprintf( | |
1241 | "SSL_CTX_use_certificate_chain_file file=%s", file), | |
1242 | cbinfo->host, NULL, errstr); | |
1243 | return 0; | |
1244 | } | |
1245 | ||
1246 | static int | |
1247 | tls_add_pkeyfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1248 | uschar ** errstr) | |
1249 | { | |
1250 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", file); | |
1251 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS file, SSL_FILETYPE_PEM)) | |
1252 | return tls_error(string_sprintf( | |
1253 | "SSL_CTX_use_PrivateKey_file file=%s", file), cbinfo->host, NULL, errstr); | |
1254 | return 0; | |
1255 | } | |
1256 | ||
1257 | ||
7be682ca PP |
1258 | /************************************************* |
1259 | * Expand key and cert file specs * | |
1260 | *************************************************/ | |
1261 | ||
f5d78688 | 1262 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
1263 | new context, if Server Name Indication was used and tls_sni was seen in |
1264 | the certificate string. | |
1265 | ||
1266 | Arguments: | |
1267 | sctx the SSL_CTX* to update | |
1268 | cbinfo various parts of session state | |
cf0c6164 | 1269 | errstr error string pointer |
7be682ca PP |
1270 | |
1271 | Returns: OK/DEFER/FAIL | |
1272 | */ | |
1273 | ||
1274 | static int | |
cf0c6164 JH |
1275 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, |
1276 | uschar ** errstr) | |
7be682ca PP |
1277 | { |
1278 | uschar *expanded; | |
1279 | ||
23bb6982 | 1280 | if (!cbinfo->certificate) |
7be682ca | 1281 | { |
ba86e143 | 1282 | if (!cbinfo->is_server) /* client */ |
23bb6982 | 1283 | return OK; |
afdb5e9c | 1284 | /* server */ |
cf0c6164 | 1285 | if (tls_install_selfsign(sctx, errstr) != OK) |
23bb6982 | 1286 | return DEFER; |
7be682ca | 1287 | } |
23bb6982 JH |
1288 | else |
1289 | { | |
ba86e143 JH |
1290 | int err; |
1291 | ||
23bb6982 JH |
1292 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
1293 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
1294 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
1295 | ) | |
1296 | reexpand_tls_files_for_sni = TRUE; | |
7be682ca | 1297 | |
cf0c6164 | 1298 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr)) |
23bb6982 JH |
1299 | return DEFER; |
1300 | ||
ba86e143 JH |
1301 | if (expanded) |
1302 | if (cbinfo->is_server) | |
1303 | { | |
1304 | const uschar * file_list = expanded; | |
1305 | int sep = 0; | |
1306 | uschar * file; | |
1307 | ||
1308 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1309 | if ((err = tls_add_certfile(sctx, cbinfo, file, errstr))) | |
1310 | return err; | |
1311 | } | |
1312 | else /* would there ever be a need for multiple client certs? */ | |
1313 | if ((err = tls_add_certfile(sctx, cbinfo, expanded, errstr))) | |
1314 | return err; | |
7be682ca | 1315 | |
5a2a0989 JH |
1316 | if ( cbinfo->privatekey |
1317 | && !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr)) | |
23bb6982 | 1318 | return DEFER; |
7be682ca | 1319 | |
23bb6982 JH |
1320 | /* If expansion was forced to fail, key_expanded will be NULL. If the result |
1321 | of the expansion is an empty string, ignore it also, and assume the private | |
1322 | key is in the same file as the certificate. */ | |
1323 | ||
1324 | if (expanded && *expanded) | |
ba86e143 JH |
1325 | if (cbinfo->is_server) |
1326 | { | |
1327 | const uschar * file_list = expanded; | |
1328 | int sep = 0; | |
1329 | uschar * file; | |
1330 | ||
1331 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1332 | if ((err = tls_add_pkeyfile(sctx, cbinfo, file, errstr))) | |
1333 | return err; | |
1334 | } | |
1335 | else /* would there ever be a need for multiple client certs? */ | |
1336 | if ((err = tls_add_pkeyfile(sctx, cbinfo, expanded, errstr))) | |
1337 | return err; | |
7be682ca PP |
1338 | } |
1339 | ||
f2de3a33 | 1340 | #ifndef DISABLE_OCSP |
f40d5be3 | 1341 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1342 | { |
47195144 | 1343 | /*XXX stack*/ |
cf0c6164 | 1344 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr)) |
3f7eeb86 PP |
1345 | return DEFER; |
1346 | ||
f40d5be3 | 1347 | if (expanded && *expanded) |
3f7eeb86 PP |
1348 | { |
1349 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f40d5be3 JH |
1350 | if ( cbinfo->u_ocsp.server.file_expanded |
1351 | && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 | 1352 | { |
f40d5be3 JH |
1353 | DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n"); |
1354 | } | |
1355 | else | |
f40d5be3 | 1356 | ocsp_load_response(sctx, cbinfo, expanded); |
3f7eeb86 PP |
1357 | } |
1358 | } | |
1359 | #endif | |
1360 | ||
7be682ca PP |
1361 | return OK; |
1362 | } | |
1363 | ||
1364 | ||
1365 | ||
1366 | ||
1367 | /************************************************* | |
1368 | * Callback to handle SNI * | |
1369 | *************************************************/ | |
1370 | ||
1371 | /* Called when acting as server during the TLS session setup if a Server Name | |
1372 | Indication extension was sent by the client. | |
1373 | ||
1374 | API documentation is OpenSSL s_server.c implementation. | |
1375 | ||
1376 | Arguments: | |
1377 | s SSL* of the current session | |
1378 | ad unknown (part of OpenSSL API) (unused) | |
1379 | arg Callback of "our" registered data | |
1380 | ||
1381 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
1382 | */ | |
1383 | ||
3bcbbbe2 | 1384 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
1385 | static int |
1386 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
1387 | { | |
1388 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 1389 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 1390 | int rc; |
3f0945ff | 1391 | int old_pool = store_pool; |
cf0c6164 | 1392 | uschar * dummy_errstr; |
7be682ca PP |
1393 | |
1394 | if (!servername) | |
1395 | return SSL_TLSEXT_ERR_OK; | |
1396 | ||
3f0945ff | 1397 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
1398 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
1399 | ||
1400 | /* Make the extension value available for expansion */ | |
3f0945ff | 1401 | store_pool = POOL_PERM; |
817d9f57 | 1402 | tls_in.sni = string_copy(US servername); |
3f0945ff | 1403 | store_pool = old_pool; |
7be682ca PP |
1404 | |
1405 | if (!reexpand_tls_files_for_sni) | |
1406 | return SSL_TLSEXT_ERR_OK; | |
1407 | ||
1408 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
1409 | not confident that memcpy wouldn't break some internal reference counting. | |
1410 | Especially since there's a references struct member, which would be off. */ | |
1411 | ||
7a8b9519 JH |
1412 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1413 | if (!(server_sni = SSL_CTX_new(TLS_server_method()))) | |
1414 | #else | |
0df4ab80 | 1415 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7a8b9519 | 1416 | #endif |
7be682ca | 1417 | { |
0abc5a13 | 1418 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
7be682ca | 1419 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); |
5a2a0989 | 1420 | goto bad; |
7be682ca PP |
1421 | } |
1422 | ||
1423 | /* Not sure how many of these are actually needed, since SSL object | |
1424 | already exists. Might even need this selfsame callback, for reneg? */ | |
1425 | ||
817d9f57 JH |
1426 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
1427 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
1428 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
1429 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
1430 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
1431 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
038597d2 | 1432 | |
cf0c6164 JH |
1433 | if ( !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr) |
1434 | || !init_ecdh(server_sni, NULL, &dummy_errstr) | |
038597d2 | 1435 | ) |
5a2a0989 | 1436 | goto bad; |
038597d2 | 1437 | |
ca954d7f JH |
1438 | if ( cbinfo->server_cipher_list |
1439 | && !SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list)) | |
5a2a0989 | 1440 | goto bad; |
ca954d7f | 1441 | |
f2de3a33 | 1442 | #ifndef DISABLE_OCSP |
f5d78688 | 1443 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1444 | { |
f5d78688 | 1445 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 1446 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
1447 | } |
1448 | #endif | |
7be682ca | 1449 | |
c3033f13 | 1450 | if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, |
cf0c6164 | 1451 | verify_callback_server, &dummy_errstr)) != OK) |
5a2a0989 | 1452 | goto bad; |
7be682ca | 1453 | |
3f7eeb86 PP |
1454 | /* do this after setup_certs, because this can require the certs for verifying |
1455 | OCSP information. */ | |
cf0c6164 | 1456 | if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK) |
5a2a0989 | 1457 | goto bad; |
a799883d | 1458 | |
7be682ca | 1459 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 1460 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca | 1461 | return SSL_TLSEXT_ERR_OK; |
5a2a0989 JH |
1462 | |
1463 | bad: return SSL_TLSEXT_ERR_ALERT_FATAL; | |
7be682ca | 1464 | } |
3bcbbbe2 | 1465 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
1466 | |
1467 | ||
1468 | ||
1469 | ||
f2de3a33 | 1470 | #ifndef DISABLE_OCSP |
f5d78688 | 1471 | |
3f7eeb86 PP |
1472 | /************************************************* |
1473 | * Callback to handle OCSP Stapling * | |
1474 | *************************************************/ | |
1475 | ||
1476 | /* Called when acting as server during the TLS session setup if the client | |
1477 | requests OCSP information with a Certificate Status Request. | |
1478 | ||
1479 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
1480 | project. | |
1481 | ||
1482 | */ | |
1483 | ||
1484 | static int | |
f5d78688 | 1485 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
1486 | { |
1487 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
47195144 | 1488 | uschar *response_der; /*XXX blob */ |
3f7eeb86 PP |
1489 | int response_der_len; |
1490 | ||
47195144 JH |
1491 | /*XXX stack: use SSL_get_certificate() to see which cert; from that work |
1492 | out which ocsp blob to send. Unfortunately, SSL_get_certificate is known | |
1493 | buggy in current OpenSSL; it returns the last cert loaded always rather than | |
1494 | the one actually presented. So we can't support a stack of OCSP proofs at | |
1495 | this time. */ | |
1496 | ||
af4a1bca | 1497 | DEBUG(D_tls) |
b3ef41c9 | 1498 | debug_printf("Received TLS status request (OCSP stapling); %s response\n", |
f5d78688 JH |
1499 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
1500 | ||
44662487 | 1501 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 1502 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
1503 | return SSL_TLSEXT_ERR_NOACK; |
1504 | ||
1505 | response_der = NULL; | |
47195144 | 1506 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, /*XXX stack*/ |
44662487 | 1507 | &response_der); |
3f7eeb86 PP |
1508 | if (response_der_len <= 0) |
1509 | return SSL_TLSEXT_ERR_NOACK; | |
1510 | ||
5e55c7a9 | 1511 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 1512 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
1513 | return SSL_TLSEXT_ERR_OK; |
1514 | } | |
1515 | ||
3f7eeb86 | 1516 | |
f5d78688 JH |
1517 | static void |
1518 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
1519 | { | |
1520 | BIO_printf(bp, "\t%s: ", str); | |
1521 | ASN1_GENERALIZEDTIME_print(bp, time); | |
1522 | BIO_puts(bp, "\n"); | |
1523 | } | |
1524 | ||
1525 | static int | |
1526 | tls_client_stapling_cb(SSL *s, void *arg) | |
1527 | { | |
1528 | tls_ext_ctx_cb * cbinfo = arg; | |
1529 | const unsigned char * p; | |
1530 | int len; | |
1531 | OCSP_RESPONSE * rsp; | |
1532 | OCSP_BASICRESP * bs; | |
1533 | int i; | |
1534 | ||
1535 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
1536 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
1537 | if(!p) | |
1538 | { | |
44662487 | 1539 | /* Expect this when we requested ocsp but got none */ |
6c6d6e48 | 1540 | if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher)) |
44662487 | 1541 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); |
f5d78688 JH |
1542 | else |
1543 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1544 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1545 | } |
018058b2 | 1546 | |
f5d78688 JH |
1547 | if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
1548 | { | |
018058b2 | 1549 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1550 | if (LOGGING(tls_cipher)) |
1eca31ca | 1551 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
1552 | else |
1553 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1554 | return 0; | |
1555 | } | |
1556 | ||
1557 | if(!(bs = OCSP_response_get1_basic(rsp))) | |
1558 | { | |
018058b2 | 1559 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1560 | if (LOGGING(tls_cipher)) |
1eca31ca | 1561 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1562 | else |
1563 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1564 | OCSP_RESPONSE_free(rsp); | |
1565 | return 0; | |
1566 | } | |
1567 | ||
1568 | /* We'd check the nonce here if we'd put one in the request. */ | |
1569 | /* However that would defeat cacheability on the server so we don't. */ | |
1570 | ||
f5d78688 JH |
1571 | /* This section of code reworked from OpenSSL apps source; |
1572 | The OpenSSL Project retains copyright: | |
1573 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1574 | */ | |
1575 | { | |
1576 | BIO * bp = NULL; | |
f5d78688 JH |
1577 | int status, reason; |
1578 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1579 | ||
57887ecc | 1580 | DEBUG(D_tls) bp = BIO_new_fp(debug_file, BIO_NOCLOSE); |
f5d78688 JH |
1581 | |
1582 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1583 | ||
1584 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1585 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1586 | ||
c3033f13 | 1587 | if ((i = OCSP_basic_verify(bs, cbinfo->verify_stack, |
44662487 | 1588 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) |
f5d78688 | 1589 | { |
018058b2 | 1590 | tls_out.ocsp = OCSP_FAILED; |
57887ecc JH |
1591 | if (LOGGING(tls_cipher)) log_write(0, LOG_MAIN, |
1592 | "Received TLS cert status response, itself unverifiable: %s", | |
1593 | ERR_reason_error_string(ERR_peek_error())); | |
f5d78688 JH |
1594 | BIO_printf(bp, "OCSP response verify failure\n"); |
1595 | ERR_print_errors(bp); | |
57887ecc | 1596 | OCSP_RESPONSE_print(bp, rsp, 0); |
c8dfb21d | 1597 | goto failed; |
f5d78688 JH |
1598 | } |
1599 | ||
1600 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1601 | ||
c8dfb21d JH |
1602 | /*XXX So we have a good stapled OCSP status. How do we know |
1603 | it is for the cert of interest? OpenSSL 1.1.0 has a routine | |
1604 | OCSP_resp_find_status() which matches on a cert id, which presumably | |
1605 | we should use. Making an id needs OCSP_cert_id_new(), which takes | |
1606 | issuerName, issuerKey, serialNumber. Are they all in the cert? | |
1607 | ||
1608 | For now, carry on blindly accepting the resp. */ | |
1609 | ||
f5d78688 | 1610 | { |
f5d78688 JH |
1611 | OCSP_SINGLERESP * single; |
1612 | ||
c8dfb21d JH |
1613 | #ifdef EXIM_HAVE_OCSP_RESP_COUNT |
1614 | if (OCSP_resp_count(bs) != 1) | |
1615 | #else | |
1616 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
f5d78688 | 1617 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) |
c8dfb21d | 1618 | #endif |
f5d78688 | 1619 | { |
018058b2 | 1620 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1621 | log_write(0, LOG_MAIN, "OCSP stapling " |
1622 | "with multiple responses not handled"); | |
c8dfb21d | 1623 | goto failed; |
f5d78688 JH |
1624 | } |
1625 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1626 | status = OCSP_single_get0_status(single, &reason, &rev, |
1627 | &thisupd, &nextupd); | |
f5d78688 JH |
1628 | } |
1629 | ||
f5d78688 JH |
1630 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1631 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1632 | if (!OCSP_check_validity(thisupd, nextupd, |
1633 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1634 | { |
018058b2 | 1635 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1636 | DEBUG(D_tls) ERR_print_errors(bp); |
1637 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
f5d78688 | 1638 | } |
44662487 | 1639 | else |
f5d78688 | 1640 | { |
44662487 JH |
1641 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1642 | OCSP_cert_status_str(status)); | |
1643 | switch(status) | |
1644 | { | |
1645 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1646 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1647 | i = 1; |
c8dfb21d | 1648 | goto good; |
44662487 | 1649 | case V_OCSP_CERTSTATUS_REVOKED: |
018058b2 | 1650 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1651 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1652 | reason != -1 ? "; reason: " : "", | |
1653 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1654 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
44662487 JH |
1655 | break; |
1656 | default: | |
018058b2 | 1657 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1658 | log_write(0, LOG_MAIN, |
1659 | "Server certificate status unknown, in OCSP stapling"); | |
44662487 JH |
1660 | break; |
1661 | } | |
f5d78688 | 1662 | } |
c8dfb21d JH |
1663 | failed: |
1664 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1665 | good: | |
f5d78688 JH |
1666 | BIO_free(bp); |
1667 | } | |
1668 | ||
1669 | OCSP_RESPONSE_free(rsp); | |
1670 | return i; | |
1671 | } | |
f2de3a33 | 1672 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1673 | |
1674 | ||
059ec3d9 PH |
1675 | /************************************************* |
1676 | * Initialize for TLS * | |
1677 | *************************************************/ | |
1678 | ||
e51c7be2 JH |
1679 | /* Called from both server and client code, to do preliminary initialization |
1680 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1681 | |
1682 | Arguments: | |
946ecbe0 | 1683 | ctxp returned SSL context |
059ec3d9 PH |
1684 | host connected host, if client; NULL if server |
1685 | dhparam DH parameter file | |
1686 | certificate certificate file | |
1687 | privatekey private key | |
f5d78688 | 1688 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1689 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1690 | cbp place to put allocated callback context |
cf0c6164 | 1691 | errstr error string pointer |
059ec3d9 PH |
1692 | |
1693 | Returns: OK/DEFER/FAIL | |
1694 | */ | |
1695 | ||
1696 | static int | |
817d9f57 | 1697 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1698 | uschar *privatekey, |
f2de3a33 | 1699 | #ifndef DISABLE_OCSP |
47195144 | 1700 | uschar *ocsp_file, /*XXX stack, in server*/ |
3f7eeb86 | 1701 | #endif |
cf0c6164 | 1702 | address_item *addr, tls_ext_ctx_cb ** cbp, uschar ** errstr) |
059ec3d9 | 1703 | { |
7006ee24 | 1704 | SSL_CTX * ctx; |
77bb000f | 1705 | long init_options; |
7be682ca | 1706 | int rc; |
a7538db1 | 1707 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1708 | |
1709 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
1710 | cbinfo->certificate = certificate; | |
1711 | cbinfo->privatekey = privatekey; | |
a6510420 | 1712 | cbinfo->is_server = host==NULL; |
f2de3a33 | 1713 | #ifndef DISABLE_OCSP |
c3033f13 | 1714 | cbinfo->verify_stack = NULL; |
a6510420 | 1715 | if (!host) |
f5d78688 JH |
1716 | { |
1717 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1718 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1719 | cbinfo->u_ocsp.server.response = NULL; | |
1720 | } | |
1721 | else | |
1722 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1723 | #endif |
7be682ca | 1724 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1725 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1726 | cbinfo->host = host; |
0cbf2b82 | 1727 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1728 | cbinfo->event_action = NULL; |
1729 | #endif | |
77bb000f | 1730 | |
7434882d | 1731 | #ifdef EXIM_NEED_OPENSSL_INIT |
059ec3d9 PH |
1732 | SSL_load_error_strings(); /* basic set up */ |
1733 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 1734 | #endif |
059ec3d9 | 1735 | |
c8dfb21d | 1736 | #ifdef EXIM_HAVE_SHA256 |
77bb000f | 1737 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1738 | list of available digests. */ |
1739 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1740 | #endif |
a0475b69 | 1741 | |
f0f5a555 PP |
1742 | /* Create a context. |
1743 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1744 | negotiation in the different methods; as far as I can tell, the only | |
1745 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1746 | when OpenSSL is built without SSLv2 support. | |
1747 | By disabling with openssl_options, we can let admins re-enable with the | |
1748 | existing knob. */ | |
059ec3d9 | 1749 | |
7a8b9519 JH |
1750 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1751 | if (!(ctx = SSL_CTX_new(host ? TLS_client_method() : TLS_server_method()))) | |
1752 | #else | |
7006ee24 | 1753 | if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method()))) |
7a8b9519 | 1754 | #endif |
7006ee24 | 1755 | return tls_error(US"SSL_CTX_new", host, NULL, errstr); |
059ec3d9 PH |
1756 | |
1757 | /* It turns out that we need to seed the random number generator this early in | |
1758 | order to get the full complement of ciphers to work. It took me roughly a day | |
1759 | of work to discover this by experiment. | |
1760 | ||
1761 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1762 | there. Otherwise, we have to make something up as best we can. Double check | |
1763 | afterwards. */ | |
1764 | ||
1765 | if (!RAND_status()) | |
1766 | { | |
1767 | randstuff r; | |
9e3331ea | 1768 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1769 | r.p = getpid(); |
1770 | ||
5903c6ff JH |
1771 | RAND_seed(US (&r), sizeof(r)); |
1772 | RAND_seed(US big_buffer, big_buffer_size); | |
1773 | if (addr != NULL) RAND_seed(US addr, sizeof(addr)); | |
059ec3d9 PH |
1774 | |
1775 | if (!RAND_status()) | |
7199e1ee | 1776 | return tls_error(US"RAND_status", host, |
cf0c6164 | 1777 | US"unable to seed random number generator", errstr); |
059ec3d9 PH |
1778 | } |
1779 | ||
1780 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1781 | level. */ | |
1782 | ||
7006ee24 | 1783 | DEBUG(D_tls) SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); |
8a40db1c JH |
1784 | #ifdef OPENSSL_HAVE_KEYLOG_CB |
1785 | DEBUG(D_tls) SSL_CTX_set_keylog_callback(ctx, (void (*)())keylog_callback); | |
1786 | #endif | |
059ec3d9 | 1787 | |
c80c5570 | 1788 | /* Automatically re-try reads/writes after renegotiation. */ |
7006ee24 | 1789 | (void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1790 | |
77bb000f PP |
1791 | /* Apply administrator-supplied work-arounds. |
1792 | Historically we applied just one requested option, | |
1793 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1794 | moved to an administrator-controlled list of options to specify and | |
1795 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1796 | |
77bb000f PP |
1797 | No OpenSSL version number checks: the options we accept depend upon the |
1798 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1799 | |
7006ee24 | 1800 | if (!tls_openssl_options_parse(openssl_options, &init_options)) |
cf0c6164 | 1801 | return tls_error(US"openssl_options parsing failed", host, NULL, errstr); |
77bb000f PP |
1802 | |
1803 | if (init_options) | |
1804 | { | |
1805 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); | |
7006ee24 | 1806 | if (!(SSL_CTX_set_options(ctx, init_options))) |
77bb000f | 1807 | return tls_error(string_sprintf( |
cf0c6164 | 1808 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL, errstr); |
77bb000f PP |
1809 | } |
1810 | else | |
1811 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 | 1812 | |
d7f31bb6 JH |
1813 | #ifdef OPENSSL_HAVE_NUM_TICKETS |
1814 | SSL_CTX_set_num_tickets(ctx, 0); /* send no TLS1.3 stateful-tickets */ | |
1815 | #endif | |
1816 | ||
a28050f8 JH |
1817 | /* We'd like to disable session cache unconditionally, but foolish Outlook |
1818 | Express clients then give up the first TLS connection and make a second one | |
1819 | (which works). Only when there is an IMAP service on the same machine. | |
1820 | Presumably OE is trying to use the cache for A on B. Leave it enabled for | |
1821 | now, until we work out a decent way of presenting control to the config. It | |
1822 | will never be used because we use a new context every time. */ | |
1823 | #ifdef notdef | |
7006ee24 | 1824 | (void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF); |
a28050f8 | 1825 | #endif |
7006ee24 | 1826 | |
059ec3d9 | 1827 | /* Initialize with DH parameters if supplied */ |
10ca4f1c | 1828 | /* Initialize ECDH temp key parameter selection */ |
059ec3d9 | 1829 | |
7006ee24 JH |
1830 | if ( !init_dh(ctx, dhparam, host, errstr) |
1831 | || !init_ecdh(ctx, host, errstr) | |
038597d2 PP |
1832 | ) |
1833 | return DEFER; | |
059ec3d9 | 1834 | |
3f7eeb86 | 1835 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 1836 | |
7006ee24 | 1837 | if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK) |
23bb6982 | 1838 | return rc; |
c91535f3 | 1839 | |
c3033f13 JH |
1840 | /* If we need to handle SNI or OCSP, do so */ |
1841 | ||
3bcbbbe2 | 1842 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
c3033f13 JH |
1843 | # ifndef DISABLE_OCSP |
1844 | if (!(cbinfo->verify_stack = sk_X509_new_null())) | |
1845 | { | |
1846 | DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n"); | |
1847 | return FAIL; | |
1848 | } | |
1849 | # endif | |
1850 | ||
7a8b9519 | 1851 | if (!host) /* server */ |
3f0945ff | 1852 | { |
f2de3a33 | 1853 | # ifndef DISABLE_OCSP |
f5d78688 | 1854 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
1855 | the option exists, not what the current expansion might be, as SNI might |
1856 | change the certificate and OCSP file in use between now and the time the | |
1857 | callback is invoked. */ | |
f5d78688 | 1858 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1859 | { |
7006ee24 JH |
1860 | SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb); |
1861 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
3f7eeb86 | 1862 | } |
f5d78688 | 1863 | # endif |
3f0945ff PP |
1864 | /* We always do this, so that $tls_sni is available even if not used in |
1865 | tls_certificate */ | |
7006ee24 JH |
1866 | SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); |
1867 | SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo); | |
3f0945ff | 1868 | } |
f2de3a33 | 1869 | # ifndef DISABLE_OCSP |
f5d78688 JH |
1870 | else /* client */ |
1871 | if(ocsp_file) /* wanting stapling */ | |
1872 | { | |
1873 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
1874 | { | |
1875 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
1876 | return FAIL; | |
1877 | } | |
7006ee24 JH |
1878 | SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb); |
1879 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
f5d78688 JH |
1880 | } |
1881 | # endif | |
7be682ca | 1882 | #endif |
059ec3d9 | 1883 | |
e51c7be2 | 1884 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 1885 | |
c8dfb21d | 1886 | #ifdef EXIM_HAVE_EPHEM_RSA_KEX |
059ec3d9 | 1887 | /* Set up the RSA callback */ |
7006ee24 | 1888 | SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); |
c8dfb21d | 1889 | #endif |
059ec3d9 PH |
1890 | |
1891 | /* Finally, set the timeout, and we are done */ | |
1892 | ||
7006ee24 | 1893 | SSL_CTX_set_timeout(ctx, ssl_session_timeout); |
059ec3d9 | 1894 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 1895 | |
817d9f57 | 1896 | *cbp = cbinfo; |
7006ee24 | 1897 | *ctxp = ctx; |
7be682ca | 1898 | |
059ec3d9 PH |
1899 | return OK; |
1900 | } | |
1901 | ||
1902 | ||
1903 | ||
1904 | ||
1905 | /************************************************* | |
1906 | * Get name of cipher in use * | |
1907 | *************************************************/ | |
1908 | ||
817d9f57 | 1909 | /* |
059ec3d9 | 1910 | Argument: pointer to an SSL structure for the connection |
817d9f57 JH |
1911 | buffer to use for answer |
1912 | size of buffer | |
1913 | pointer to number of bits for cipher | |
059ec3d9 PH |
1914 | Returns: nothing |
1915 | */ | |
1916 | ||
1917 | static void | |
817d9f57 | 1918 | construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits) |
059ec3d9 | 1919 | { |
7a8b9519 | 1920 | /* With OpenSSL 1.0.0a, 'c' needs to be const but the documentation doesn't |
57b3a7f5 PP |
1921 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have |
1922 | the accessor functions use const in the prototype. */ | |
059ec3d9 | 1923 | |
7a8b9519 JH |
1924 | const uschar * ver = CUS SSL_get_version(ssl); |
1925 | const SSL_CIPHER * c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); | |
059ec3d9 | 1926 | |
817d9f57 | 1927 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 1928 | |
817d9f57 JH |
1929 | string_format(cipherbuf, bsize, "%s:%s:%u", ver, |
1930 | SSL_CIPHER_get_name(c), *bits); | |
059ec3d9 PH |
1931 | |
1932 | DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); | |
1933 | } | |
1934 | ||
1935 | ||
f69979cf | 1936 | static void |
70e384dd | 1937 | peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned siz) |
f69979cf JH |
1938 | { |
1939 | /*XXX we might consider a list-of-certs variable for the cert chain. | |
1940 | SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support | |
1941 | in list-handling functions, also consider the difference between the entire | |
1942 | chain and the elements sent by the peer. */ | |
1943 | ||
70e384dd JH |
1944 | tlsp->peerdn = NULL; |
1945 | ||
f69979cf JH |
1946 | /* Will have already noted peercert on a verify fail; possibly not the leaf */ |
1947 | if (!tlsp->peercert) | |
1948 | tlsp->peercert = SSL_get_peer_certificate(ssl); | |
1949 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
1950 | if (tlsp->peercert) | |
70e384dd JH |
1951 | if (!X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, siz)) |
1952 | { DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); } | |
1953 | else | |
1954 | { | |
1955 | peerdn[siz-1] = '\0'; | |
1956 | tlsp->peerdn = peerdn; /*XXX a static buffer... */ | |
1957 | } | |
f69979cf JH |
1958 | } |
1959 | ||
1960 | ||
059ec3d9 PH |
1961 | |
1962 | ||
1963 | ||
1964 | /************************************************* | |
1965 | * Set up for verifying certificates * | |
1966 | *************************************************/ | |
1967 | ||
0e8aed8a | 1968 | #ifndef DISABLE_OCSP |
c3033f13 JH |
1969 | /* Load certs from file, return TRUE on success */ |
1970 | ||
1971 | static BOOL | |
1972 | chain_from_pem_file(const uschar * file, STACK_OF(X509) * verify_stack) | |
1973 | { | |
1974 | BIO * bp; | |
1975 | X509 * x; | |
1976 | ||
dec766a1 WB |
1977 | while (sk_X509_num(verify_stack) > 0) |
1978 | X509_free(sk_X509_pop(verify_stack)); | |
1979 | ||
c3033f13 JH |
1980 | if (!(bp = BIO_new_file(CS file, "r"))) return FALSE; |
1981 | while ((x = PEM_read_bio_X509(bp, NULL, 0, NULL))) | |
1982 | sk_X509_push(verify_stack, x); | |
1983 | BIO_free(bp); | |
1984 | return TRUE; | |
1985 | } | |
0e8aed8a | 1986 | #endif |
c3033f13 JH |
1987 | |
1988 | ||
1989 | ||
dec766a1 WB |
1990 | /* Called by both client and server startup; on the server possibly |
1991 | repeated after a Server Name Indication. | |
059ec3d9 PH |
1992 | |
1993 | Arguments: | |
7be682ca | 1994 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
1995 | certs certs file or NULL |
1996 | crl CRL file or NULL | |
1997 | host NULL in a server; the remote host in a client | |
1998 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
1999 | otherwise passed as FALSE | |
983207c1 | 2000 | cert_vfy_cb Callback function for certificate verification |
cf0c6164 | 2001 | errstr error string pointer |
059ec3d9 PH |
2002 | |
2003 | Returns: OK/DEFER/FAIL | |
2004 | */ | |
2005 | ||
2006 | static int | |
983207c1 | 2007 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 2008 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr) |
059ec3d9 PH |
2009 | { |
2010 | uschar *expcerts, *expcrl; | |
2011 | ||
cf0c6164 | 2012 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts, errstr)) |
059ec3d9 | 2013 | return DEFER; |
57cc2785 | 2014 | DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts); |
059ec3d9 | 2015 | |
10a831a3 | 2016 | if (expcerts && *expcerts) |
059ec3d9 | 2017 | { |
10a831a3 JH |
2018 | /* Tell the library to use its compiled-in location for the system default |
2019 | CA bundle. Then add the ones specified in the config, if any. */ | |
cb1d7830 | 2020 | |
10a831a3 | 2021 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
cf0c6164 | 2022 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr); |
10a831a3 JH |
2023 | |
2024 | if (Ustrcmp(expcerts, "system") != 0) | |
059ec3d9 | 2025 | { |
cb1d7830 JH |
2026 | struct stat statbuf; |
2027 | ||
cb1d7830 JH |
2028 | if (Ustat(expcerts, &statbuf) < 0) |
2029 | { | |
2030 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2031 | "failed to stat %s for certificates", expcerts); | |
2032 | return DEFER; | |
2033 | } | |
059ec3d9 | 2034 | else |
059ec3d9 | 2035 | { |
cb1d7830 JH |
2036 | uschar *file, *dir; |
2037 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
2038 | { file = NULL; dir = expcerts; } | |
2039 | else | |
c3033f13 JH |
2040 | { |
2041 | file = expcerts; dir = NULL; | |
2042 | #ifndef DISABLE_OCSP | |
2043 | /* In the server if we will be offering an OCSP proof, load chain from | |
2044 | file for verifying the OCSP proof at load time. */ | |
2045 | ||
2046 | if ( !host | |
2047 | && statbuf.st_size > 0 | |
2048 | && server_static_cbinfo->u_ocsp.server.file | |
2049 | && !chain_from_pem_file(file, server_static_cbinfo->verify_stack) | |
2050 | ) | |
2051 | { | |
2052 | log_write(0, LOG_MAIN|LOG_PANIC, | |
57887ecc | 2053 | "failed to load cert chain from %s", file); |
c3033f13 JH |
2054 | return DEFER; |
2055 | } | |
2056 | #endif | |
2057 | } | |
cb1d7830 JH |
2058 | |
2059 | /* If a certificate file is empty, the next function fails with an | |
2060 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
2061 | certificates are recognized, but the error message is still misleading (it | |
c3033f13 | 2062 | says no certificate was supplied). But this is better. */ |
cb1d7830 | 2063 | |
f2f2c91b JH |
2064 | if ( (!file || statbuf.st_size > 0) |
2065 | && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
cf0c6164 | 2066 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr); |
cb1d7830 JH |
2067 | |
2068 | /* Load the list of CAs for which we will accept certs, for sending | |
2069 | to the client. This is only for the one-file tls_verify_certificates | |
2070 | variant. | |
d7978c0f JH |
2071 | If a list isn't loaded into the server, but some verify locations are set, |
2072 | the server end appears to make a wildcard request for client certs. | |
10a831a3 | 2073 | Meanwhile, the client library as default behaviour *ignores* the list |
cb1d7830 JH |
2074 | we send over the wire - see man SSL_CTX_set_client_cert_cb. |
2075 | Because of this, and that the dir variant is likely only used for | |
d7978c0f JH |
2076 | the public-CA bundle (not for a private CA), not worth fixing. */ |
2077 | ||
f2f2c91b | 2078 | if (file) |
cb1d7830 | 2079 | { |
2009ecca | 2080 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); |
dec766a1 WB |
2081 | |
2082 | SSL_CTX_set_client_CA_list(sctx, names); | |
f2f2c91b | 2083 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", |
cb1d7830 | 2084 | sk_X509_NAME_num(names)); |
cb1d7830 | 2085 | } |
059ec3d9 PH |
2086 | } |
2087 | } | |
2088 | ||
2089 | /* Handle a certificate revocation list. */ | |
2090 | ||
10a831a3 | 2091 | #if OPENSSL_VERSION_NUMBER > 0x00907000L |
059ec3d9 | 2092 | |
8b417f2c | 2093 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
10a831a3 | 2094 | merely reformatted it into the Exim code style.) |
8b417f2c | 2095 | |
10a831a3 JH |
2096 | "From here I changed the code to add support for multiple crl's |
2097 | in pem format in one file or to support hashed directory entries in | |
2098 | pem format instead of a file. This method now uses the library function | |
2099 | X509_STORE_load_locations to add the CRL location to the SSL context. | |
2100 | OpenSSL will then handle the verify against CA certs and CRLs by | |
2101 | itself in the verify callback." */ | |
8b417f2c | 2102 | |
cf0c6164 | 2103 | if (!expand_check(crl, US"tls_crl", &expcrl, errstr)) return DEFER; |
10a831a3 | 2104 | if (expcrl && *expcrl) |
059ec3d9 | 2105 | { |
8b417f2c PH |
2106 | struct stat statbufcrl; |
2107 | if (Ustat(expcrl, &statbufcrl) < 0) | |
2108 | { | |
2109 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2110 | "failed to stat %s for certificates revocation lists", expcrl); | |
2111 | return DEFER; | |
2112 | } | |
2113 | else | |
059ec3d9 | 2114 | { |
8b417f2c PH |
2115 | /* is it a file or directory? */ |
2116 | uschar *file, *dir; | |
7be682ca | 2117 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 2118 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 2119 | { |
8b417f2c PH |
2120 | file = NULL; |
2121 | dir = expcrl; | |
2122 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
2123 | } |
2124 | else | |
2125 | { | |
8b417f2c PH |
2126 | file = expcrl; |
2127 | dir = NULL; | |
2128 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 2129 | } |
8b417f2c | 2130 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
cf0c6164 | 2131 | return tls_error(US"X509_STORE_load_locations", host, NULL, errstr); |
8b417f2c PH |
2132 | |
2133 | /* setting the flags to check against the complete crl chain */ | |
2134 | ||
2135 | X509_STORE_set_flags(cvstore, | |
2136 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 2137 | } |
059ec3d9 PH |
2138 | } |
2139 | ||
10a831a3 | 2140 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ |
059ec3d9 PH |
2141 | |
2142 | /* If verification is optional, don't fail if no certificate */ | |
2143 | ||
7be682ca | 2144 | SSL_CTX_set_verify(sctx, |
5a2a0989 | 2145 | SSL_VERIFY_PEER | (optional ? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 2146 | cert_vfy_cb); |
059ec3d9 PH |
2147 | } |
2148 | ||
2149 | return OK; | |
2150 | } | |
2151 | ||
2152 | ||
2153 | ||
2154 | /************************************************* | |
2155 | * Start a TLS session in a server * | |
2156 | *************************************************/ | |
2157 | ||
2158 | /* This is called when Exim is running as a server, after having received | |
2159 | the STARTTLS command. It must respond to that command, and then negotiate | |
2160 | a TLS session. | |
2161 | ||
2162 | Arguments: | |
2163 | require_ciphers allowed ciphers | |
cf0c6164 | 2164 | errstr pointer to error message |
059ec3d9 PH |
2165 | |
2166 | Returns: OK on success | |
2167 | DEFER for errors before the start of the negotiation | |
4c04137d | 2168 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
2169 | continue running. |
2170 | */ | |
2171 | ||
2172 | int | |
cf0c6164 | 2173 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
2174 | { |
2175 | int rc; | |
cf0c6164 JH |
2176 | uschar * expciphers; |
2177 | tls_ext_ctx_cb * cbinfo; | |
f69979cf | 2178 | static uschar peerdn[256]; |
817d9f57 | 2179 | static uschar cipherbuf[256]; |
059ec3d9 PH |
2180 | |
2181 | /* Check for previous activation */ | |
2182 | ||
74f1a423 | 2183 | if (tls_in.active.sock >= 0) |
059ec3d9 | 2184 | { |
cf0c6164 | 2185 | tls_error(US"STARTTLS received after TLS started", NULL, US"", errstr); |
925ac8e4 | 2186 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
2187 | return FAIL; |
2188 | } | |
2189 | ||
2190 | /* Initialize the SSL library. If it fails, it will already have logged | |
2191 | the error. */ | |
2192 | ||
817d9f57 | 2193 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 2194 | #ifndef DISABLE_OCSP |
47195144 | 2195 | tls_ocsp_file, /*XXX stack*/ |
3f7eeb86 | 2196 | #endif |
cf0c6164 | 2197 | NULL, &server_static_cbinfo, errstr); |
059ec3d9 | 2198 | if (rc != OK) return rc; |
817d9f57 | 2199 | cbinfo = server_static_cbinfo; |
059ec3d9 | 2200 | |
cf0c6164 | 2201 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr)) |
059ec3d9 PH |
2202 | return FAIL; |
2203 | ||
2204 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
2205 | were historically separated by underscores. So that I can use either form in my |
2206 | tests, and also for general convenience, we turn underscores into hyphens here. | |
0c3807a8 JH |
2207 | |
2208 | XXX SSL_CTX_set_cipher_list() is replaced by SSL_CTX_set_ciphersuites() | |
2209 | for TLS 1.3 . Since we do not call it at present we get the default list: | |
2210 | TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256 | |
17c76198 | 2211 | */ |
059ec3d9 | 2212 | |
c3033f13 | 2213 | if (expciphers) |
059ec3d9 | 2214 | { |
c3033f13 | 2215 | uschar * s = expciphers; |
059ec3d9 PH |
2216 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } |
2217 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); | |
817d9f57 | 2218 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
cf0c6164 | 2219 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr); |
7be682ca | 2220 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
2221 | } |
2222 | ||
2223 | /* If this is a host for which certificate verification is mandatory or | |
2224 | optional, set up appropriately. */ | |
2225 | ||
817d9f57 | 2226 | tls_in.certificate_verified = FALSE; |
c0635b6d | 2227 | #ifdef SUPPORT_DANE |
53a7196b JH |
2228 | tls_in.dane_verified = FALSE; |
2229 | #endif | |
a2ff477a | 2230 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
2231 | |
2232 | if (verify_check_host(&tls_verify_hosts) == OK) | |
2233 | { | |
983207c1 | 2234 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2235 | FALSE, verify_callback_server, errstr); |
059ec3d9 | 2236 | if (rc != OK) return rc; |
a2ff477a | 2237 | server_verify_optional = FALSE; |
059ec3d9 PH |
2238 | } |
2239 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
2240 | { | |
983207c1 | 2241 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2242 | TRUE, verify_callback_server, errstr); |
059ec3d9 | 2243 | if (rc != OK) return rc; |
a2ff477a | 2244 | server_verify_optional = TRUE; |
059ec3d9 PH |
2245 | } |
2246 | ||
2247 | /* Prepare for new connection */ | |
2248 | ||
cf0c6164 JH |
2249 | if (!(server_ssl = SSL_new(server_ctx))) |
2250 | return tls_error(US"SSL_new", NULL, NULL, errstr); | |
da3ad30d PP |
2251 | |
2252 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
2253 | * | |
2254 | * With the SSL_clear(), we get strange interoperability bugs with | |
2255 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
2256 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
2257 | * | |
2258 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
2259 | * session shutdown. In this case, we have a brand new object and there's no | |
2260 | * obvious reason to immediately clear it. I'm guessing that this was | |
2261 | * originally added because of incomplete initialisation which the clear fixed, | |
2262 | * in some historic release. | |
2263 | */ | |
059ec3d9 PH |
2264 | |
2265 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2266 | on connection, where outputting anything now upsets the clients and tends to | |
2267 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2268 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2269 | mode, the fflush() happens when smtp_getc() is called. */ | |
2270 | ||
817d9f57 JH |
2271 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
2272 | if (!tls_in.on_connect) | |
059ec3d9 | 2273 | { |
925ac8e4 | 2274 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
059ec3d9 PH |
2275 | fflush(smtp_out); |
2276 | } | |
2277 | ||
2278 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
2279 | that the OpenSSL library doesn't. */ | |
2280 | ||
817d9f57 JH |
2281 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
2282 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
2283 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
2284 | |
2285 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
2286 | ||
2287 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2288 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
817d9f57 | 2289 | rc = SSL_accept(server_ssl); |
c2a1bba0 | 2290 | ALARM_CLR(0); |
059ec3d9 PH |
2291 | |
2292 | if (rc <= 0) | |
2293 | { | |
cf0c6164 | 2294 | (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr); |
059ec3d9 PH |
2295 | return FAIL; |
2296 | } | |
2297 | ||
2298 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
25fa0868 JH |
2299 | ERR_clear_error(); /* Even success can leave errors in the stack. Seen with |
2300 | anon-authentication ciphersuite negociated. */ | |
059ec3d9 PH |
2301 | |
2302 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2303 | and initialize things. */ | |
2304 | ||
f69979cf JH |
2305 | peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn)); |
2306 | ||
817d9f57 JH |
2307 | construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits); |
2308 | tls_in.cipher = cipherbuf; | |
059ec3d9 PH |
2309 | |
2310 | DEBUG(D_tls) | |
2311 | { | |
2312 | uschar buf[2048]; | |
817d9f57 | 2313 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL) |
059ec3d9 PH |
2314 | debug_printf("Shared ciphers: %s\n", buf); |
2315 | } | |
2316 | ||
9d1c15ef JH |
2317 | /* Record the certificate we presented */ |
2318 | { | |
2319 | X509 * crt = SSL_get_certificate(server_ssl); | |
2320 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
2321 | } | |
059ec3d9 | 2322 | |
817d9f57 JH |
2323 | /* Only used by the server-side tls (tls_in), including tls_getc. |
2324 | Client-side (tls_out) reads (seem to?) go via | |
2325 | smtp_read_response()/ip_recv(). | |
2326 | Hence no need to duplicate for _in and _out. | |
2327 | */ | |
b808677c | 2328 | if (!ssl_xfer_buffer) ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 | 2329 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; |
8b77d27a | 2330 | ssl_xfer_eof = ssl_xfer_error = FALSE; |
059ec3d9 PH |
2331 | |
2332 | receive_getc = tls_getc; | |
0d81dabc | 2333 | receive_getbuf = tls_getbuf; |
584e96c6 | 2334 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2335 | receive_ungetc = tls_ungetc; |
2336 | receive_feof = tls_feof; | |
2337 | receive_ferror = tls_ferror; | |
58eb016e | 2338 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2339 | |
74f1a423 JH |
2340 | tls_in.active.sock = fileno(smtp_out); |
2341 | tls_in.active.tls_ctx = NULL; /* not using explicit ctx for server-side */ | |
059ec3d9 PH |
2342 | return OK; |
2343 | } | |
2344 | ||
2345 | ||
2346 | ||
2347 | ||
043b1248 JH |
2348 | static int |
2349 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
cf0c6164 JH |
2350 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo, |
2351 | uschar ** errstr) | |
043b1248 JH |
2352 | { |
2353 | int rc; | |
94431adb | 2354 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
043b1248 JH |
2355 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only |
2356 | the specified host patterns if one of them is defined */ | |
2357 | ||
610ff438 JH |
2358 | if ( ( !ob->tls_verify_hosts |
2359 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2360 | ) | |
3c07dd2d | 2361 | || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK |
aa2a70ba | 2362 | ) |
043b1248 | 2363 | client_verify_optional = FALSE; |
3c07dd2d | 2364 | else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
2365 | client_verify_optional = TRUE; |
2366 | else | |
2367 | return OK; | |
2368 | ||
2369 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
cf0c6164 JH |
2370 | ob->tls_crl, host, client_verify_optional, verify_callback_client, |
2371 | errstr)) != OK) | |
aa2a70ba | 2372 | return rc; |
043b1248 | 2373 | |
3c07dd2d | 2374 | if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 2375 | { |
4af0d74a | 2376 | cbinfo->verify_cert_hostnames = |
8c5d388a | 2377 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2378 | string_domain_utf8_to_alabel(host->name, NULL); |
2379 | #else | |
2380 | host->name; | |
2381 | #endif | |
aa2a70ba JH |
2382 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", |
2383 | cbinfo->verify_cert_hostnames); | |
043b1248 | 2384 | } |
043b1248 JH |
2385 | return OK; |
2386 | } | |
059ec3d9 | 2387 | |
fde080a4 | 2388 | |
c0635b6d | 2389 | #ifdef SUPPORT_DANE |
fde080a4 | 2390 | static int |
cf0c6164 | 2391 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa, uschar ** errstr) |
fde080a4 | 2392 | { |
fde080a4 JH |
2393 | dns_scan dnss; |
2394 | const char * hostnames[2] = { CS host->name, NULL }; | |
2395 | int found = 0; | |
2396 | ||
2397 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
cf0c6164 | 2398 | return tls_error(US"hostnames load", host, NULL, errstr); |
fde080a4 | 2399 | |
d7978c0f | 2400 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; |
fde080a4 | 2401 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
1b76ad22 | 2402 | ) if (rr->type == T_TLSA && rr->size > 3) |
fde080a4 | 2403 | { |
c3033f13 | 2404 | const uschar * p = rr->data; |
fde080a4 JH |
2405 | uint8_t usage, selector, mtype; |
2406 | const char * mdname; | |
2407 | ||
fde080a4 | 2408 | usage = *p++; |
133d2546 JH |
2409 | |
2410 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
2411 | if (usage != 2 && usage != 3) continue; | |
2412 | ||
fde080a4 JH |
2413 | selector = *p++; |
2414 | mtype = *p++; | |
2415 | ||
2416 | switch (mtype) | |
2417 | { | |
133d2546 JH |
2418 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
2419 | case 0: mdname = NULL; break; | |
2420 | case 1: mdname = "sha256"; break; | |
2421 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
2422 | } |
2423 | ||
133d2546 | 2424 | found++; |
fde080a4 JH |
2425 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
2426 | { | |
2427 | default: | |
cf0c6164 | 2428 | return tls_error(US"tlsa load", host, NULL, errstr); |
c035b645 | 2429 | case 0: /* action not taken */ |
fde080a4 JH |
2430 | case 1: break; |
2431 | } | |
594706ea JH |
2432 | |
2433 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
2434 | } |
2435 | ||
2436 | if (found) | |
2437 | return OK; | |
2438 | ||
133d2546 | 2439 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 2440 | return DEFER; |
fde080a4 | 2441 | } |
c0635b6d | 2442 | #endif /*SUPPORT_DANE*/ |
fde080a4 JH |
2443 | |
2444 | ||
2445 | ||
059ec3d9 PH |
2446 | /************************************************* |
2447 | * Start a TLS session in a client * | |
2448 | *************************************************/ | |
2449 | ||
2450 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2451 | ||
2452 | Argument: | |
2453 | fd the fd of the connection | |
afdb5e9c JH |
2454 | host connected host (for messages and option-tests) |
2455 | addr the first address (for some randomness; can be NULL) | |
a7538db1 | 2456 | tb transport (always smtp) |
0e66b3b6 | 2457 | tlsa_dnsa tlsa lookup, if DANE, else null |
afdb5e9c | 2458 | tlsp record details of channel configuration here; must be non-NULL |
cf0c6164 | 2459 | errstr error string pointer |
059ec3d9 | 2460 | |
74f1a423 | 2461 | Returns: Pointer to TLS session context, or NULL on error |
059ec3d9 PH |
2462 | */ |
2463 | ||
74f1a423 | 2464 | void * |
f5d78688 | 2465 | tls_client_start(int fd, host_item *host, address_item *addr, |
cf0c6164 | 2466 | transport_instance * tb, |
c0635b6d | 2467 | #ifdef SUPPORT_DANE |
cf0c6164 | 2468 | dns_answer * tlsa_dnsa, |
0e66b3b6 | 2469 | #endif |
74f1a423 | 2470 | tls_support * tlsp, uschar ** errstr) |
059ec3d9 | 2471 | { |
afdb5e9c JH |
2472 | smtp_transport_options_block * ob = tb |
2473 | ? (smtp_transport_options_block *)tb->options_block | |
2474 | : &smtp_transport_option_defaults; | |
74f1a423 | 2475 | exim_openssl_client_tls_ctx * exim_client_ctx; |
f69979cf | 2476 | static uschar peerdn[256]; |
868f5672 | 2477 | uschar * expciphers; |
059ec3d9 | 2478 | int rc; |
817d9f57 | 2479 | static uschar cipherbuf[256]; |
043b1248 JH |
2480 | |
2481 | #ifndef DISABLE_OCSP | |
043b1248 | 2482 | BOOL request_ocsp = FALSE; |
6634ac8d | 2483 | BOOL require_ocsp = FALSE; |
043b1248 | 2484 | #endif |
043b1248 | 2485 | |
74f1a423 JH |
2486 | rc = store_pool; |
2487 | store_pool = POOL_PERM; | |
2488 | exim_client_ctx = store_get(sizeof(exim_openssl_client_tls_ctx)); | |
2489 | store_pool = rc; | |
2490 | ||
c0635b6d | 2491 | #ifdef SUPPORT_DANE |
74f1a423 | 2492 | tlsp->tlsa_usage = 0; |
043b1248 JH |
2493 | #endif |
2494 | ||
f2de3a33 | 2495 | #ifndef DISABLE_OCSP |
043b1248 | 2496 | { |
c0635b6d | 2497 | # ifdef SUPPORT_DANE |
4f59c424 JH |
2498 | if ( tlsa_dnsa |
2499 | && ob->hosts_request_ocsp[0] == '*' | |
2500 | && ob->hosts_request_ocsp[1] == '\0' | |
2501 | ) | |
2502 | { | |
2503 | /* Unchanged from default. Use a safer one under DANE */ | |
2504 | request_ocsp = TRUE; | |
2505 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
2506 | " {= {4}{$tls_out_tlsa_usage}} } " | |
2507 | " {*}{}}"; | |
2508 | } | |
2509 | # endif | |
2510 | ||
5130845b | 2511 | if ((require_ocsp = |
3c07dd2d | 2512 | verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK)) |
fca41d5a JH |
2513 | request_ocsp = TRUE; |
2514 | else | |
c0635b6d | 2515 | # ifdef SUPPORT_DANE |
4f59c424 | 2516 | if (!request_ocsp) |
fca41d5a | 2517 | # endif |
5130845b | 2518 | request_ocsp = |
3c07dd2d | 2519 | verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
043b1248 | 2520 | } |
f5d78688 | 2521 | #endif |
059ec3d9 | 2522 | |
74f1a423 | 2523 | rc = tls_init(&exim_client_ctx->ctx, host, NULL, |
65867078 | 2524 | ob->tls_certificate, ob->tls_privatekey, |
f2de3a33 | 2525 | #ifndef DISABLE_OCSP |
44662487 | 2526 | (void *)(long)request_ocsp, |
3f7eeb86 | 2527 | #endif |
cf0c6164 | 2528 | addr, &client_static_cbinfo, errstr); |
74f1a423 | 2529 | if (rc != OK) return NULL; |
059ec3d9 | 2530 | |
74f1a423 | 2531 | tlsp->certificate_verified = FALSE; |
a2ff477a | 2532 | client_verify_callback_called = FALSE; |
059ec3d9 | 2533 | |
5ec37a55 PP |
2534 | expciphers = NULL; |
2535 | #ifdef SUPPORT_DANE | |
2536 | if (tlsa_dnsa) | |
2537 | { | |
2538 | /* We fall back to tls_require_ciphers if unset, empty or forced failure, but | |
2539 | other failures should be treated as problems. */ | |
2540 | if (ob->dane_require_tls_ciphers && | |
2541 | !expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2542 | &expciphers, errstr)) | |
74f1a423 | 2543 | return NULL; |
5ec37a55 PP |
2544 | if (expciphers && *expciphers == '\0') |
2545 | expciphers = NULL; | |
2546 | } | |
2547 | #endif | |
2548 | if (!expciphers && | |
2549 | !expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", | |
2550 | &expciphers, errstr)) | |
74f1a423 | 2551 | return NULL; |
059ec3d9 PH |
2552 | |
2553 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
2554 | are separated by underscores. So that I can use either form in my tests, and | |
2555 | also for general convenience, we turn underscores into hyphens here. */ | |
2556 | ||
cf0c6164 | 2557 | if (expciphers) |
059ec3d9 PH |
2558 | { |
2559 | uschar *s = expciphers; | |
cf0c6164 | 2560 | while (*s) { if (*s == '_') *s = '-'; s++; } |
059ec3d9 | 2561 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); |
74f1a423 JH |
2562 | if (!SSL_CTX_set_cipher_list(exim_client_ctx->ctx, CS expciphers)) |
2563 | { | |
2564 | tls_error(US"SSL_CTX_set_cipher_list", host, NULL, errstr); | |
2565 | return NULL; | |
2566 | } | |
059ec3d9 PH |
2567 | } |
2568 | ||
c0635b6d | 2569 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2570 | if (tlsa_dnsa) |
a63be306 | 2571 | { |
74f1a423 | 2572 | SSL_CTX_set_verify(exim_client_ctx->ctx, |
02af313d JH |
2573 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, |
2574 | verify_callback_client_dane); | |
e5cccda9 | 2575 | |
043b1248 | 2576 | if (!DANESSL_library_init()) |
74f1a423 JH |
2577 | { |
2578 | tls_error(US"library init", host, NULL, errstr); | |
2579 | return NULL; | |
2580 | } | |
2581 | if (DANESSL_CTX_init(exim_client_ctx->ctx) <= 0) | |
2582 | { | |
2583 | tls_error(US"context init", host, NULL, errstr); | |
2584 | return NULL; | |
2585 | } | |
043b1248 JH |
2586 | } |
2587 | else | |
e51c7be2 | 2588 | |
043b1248 JH |
2589 | #endif |
2590 | ||
74f1a423 JH |
2591 | if (tls_client_basic_ctx_init(exim_client_ctx->ctx, host, ob, |
2592 | client_static_cbinfo, errstr) != OK) | |
2593 | return NULL; | |
059ec3d9 | 2594 | |
74f1a423 JH |
2595 | if (!(exim_client_ctx->ssl = SSL_new(exim_client_ctx->ctx))) |
2596 | { | |
2597 | tls_error(US"SSL_new", host, NULL, errstr); | |
2598 | return NULL; | |
2599 | } | |
2600 | SSL_set_session_id_context(exim_client_ctx->ssl, sid_ctx, Ustrlen(sid_ctx)); | |
2601 | SSL_set_fd(exim_client_ctx->ssl, fd); | |
2602 | SSL_set_connect_state(exim_client_ctx->ssl); | |
059ec3d9 | 2603 | |
65867078 | 2604 | if (ob->tls_sni) |
3f0945ff | 2605 | { |
74f1a423 JH |
2606 | if (!expand_check(ob->tls_sni, US"tls_sni", &tlsp->sni, errstr)) |
2607 | return NULL; | |
2608 | if (!tlsp->sni) | |
2c9a0e86 PP |
2609 | { |
2610 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
2611 | } | |
74f1a423 JH |
2612 | else if (!Ustrlen(tlsp->sni)) |
2613 | tlsp->sni = NULL; | |
3f0945ff PP |
2614 | else |
2615 | { | |
35731706 | 2616 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
74f1a423 JH |
2617 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tlsp->sni); |
2618 | SSL_set_tlsext_host_name(exim_client_ctx->ssl, tlsp->sni); | |
35731706 | 2619 | #else |
66802652 | 2620 | log_write(0, LOG_MAIN, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n", |
74f1a423 | 2621 | tlsp->sni); |
35731706 | 2622 | #endif |
3f0945ff PP |
2623 | } |
2624 | } | |
2625 | ||
c0635b6d | 2626 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2627 | if (tlsa_dnsa) |
74f1a423 JH |
2628 | if (dane_tlsa_load(exim_client_ctx->ssl, host, tlsa_dnsa, errstr) != OK) |
2629 | return NULL; | |
594706ea JH |
2630 | #endif |
2631 | ||
f2de3a33 | 2632 | #ifndef DISABLE_OCSP |
f5d78688 JH |
2633 | /* Request certificate status at connection-time. If the server |
2634 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
c0635b6d | 2635 | # ifdef SUPPORT_DANE |
594706ea JH |
2636 | if (request_ocsp) |
2637 | { | |
2638 | const uschar * s; | |
41afb5cb JH |
2639 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
2640 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
2641 | ) |
2642 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
2643 | this means we avoid the OCSP request, we wasted the setup | |
2644 | cost in tls_init(). */ | |
3c07dd2d | 2645 | require_ocsp = verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; |
5130845b | 2646 | request_ocsp = require_ocsp |
3c07dd2d | 2647 | || verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
594706ea JH |
2648 | } |
2649 | } | |
b50c8b84 JH |
2650 | # endif |
2651 | ||
44662487 JH |
2652 | if (request_ocsp) |
2653 | { | |
74f1a423 | 2654 | SSL_set_tlsext_status_type(exim_client_ctx->ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 | 2655 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
74f1a423 | 2656 | tlsp->ocsp = OCSP_NOT_RESP; |
44662487 | 2657 | } |
f5d78688 JH |
2658 | #endif |
2659 | ||
0cbf2b82 | 2660 | #ifndef DISABLE_EVENT |
afdb5e9c | 2661 | client_static_cbinfo->event_action = tb ? tb->event_action : NULL; |
a7538db1 | 2662 | #endif |
043b1248 | 2663 | |
059ec3d9 PH |
2664 | /* There doesn't seem to be a built-in timeout on connection. */ |
2665 | ||
2666 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
2667 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2668 | ALARM(ob->command_timeout); |
74f1a423 | 2669 | rc = SSL_connect(exim_client_ctx->ssl); |
c2a1bba0 | 2670 | ALARM_CLR(0); |
059ec3d9 | 2671 | |
c0635b6d | 2672 | #ifdef SUPPORT_DANE |
0e66b3b6 | 2673 | if (tlsa_dnsa) |
74f1a423 | 2674 | DANESSL_cleanup(exim_client_ctx->ssl); |
043b1248 JH |
2675 | #endif |
2676 | ||
059ec3d9 | 2677 | if (rc <= 0) |
74f1a423 JH |
2678 | { |
2679 | tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL, errstr); | |
2680 | return NULL; | |
2681 | } | |
059ec3d9 PH |
2682 | |
2683 | DEBUG(D_tls) debug_printf("SSL_connect succeeded\n"); | |
2684 | ||
74f1a423 | 2685 | peer_cert(exim_client_ctx->ssl, tlsp, peerdn, sizeof(peerdn)); |
059ec3d9 | 2686 | |
74f1a423 JH |
2687 | construct_cipher_name(exim_client_ctx->ssl, cipherbuf, sizeof(cipherbuf), &tlsp->bits); |
2688 | tlsp->cipher = cipherbuf; | |
059ec3d9 | 2689 | |
9d1c15ef JH |
2690 | /* Record the certificate we presented */ |
2691 | { | |
74f1a423 JH |
2692 | X509 * crt = SSL_get_certificate(exim_client_ctx->ssl); |
2693 | tlsp->ourcert = crt ? X509_dup(crt) : NULL; | |
9d1c15ef JH |
2694 | } |
2695 | ||
74f1a423 JH |
2696 | tlsp->active.sock = fd; |
2697 | tlsp->active.tls_ctx = exim_client_ctx; | |
2698 | return exim_client_ctx; | |
059ec3d9 PH |
2699 | } |
2700 | ||
2701 | ||
2702 | ||
2703 | ||
2704 | ||
0d81dabc JH |
2705 | static BOOL |
2706 | tls_refill(unsigned lim) | |
2707 | { | |
2708 | int error; | |
2709 | int inbytes; | |
2710 | ||
2711 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, | |
2712 | ssl_xfer_buffer, ssl_xfer_buffer_size); | |
2713 | ||
c2a1bba0 | 2714 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
0d81dabc JH |
2715 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, |
2716 | MIN(ssl_xfer_buffer_size, lim)); | |
2717 | error = SSL_get_error(server_ssl, inbytes); | |
c2a1bba0 | 2718 | if (smtp_receive_timeout > 0) ALARM_CLR(0); |
9723f966 JH |
2719 | |
2720 | if (had_command_timeout) /* set by signal handler */ | |
2721 | smtp_command_timeout_exit(); /* does not return */ | |
2722 | if (had_command_sigterm) | |
2723 | smtp_command_sigterm_exit(); | |
2724 | if (had_data_timeout) | |
2725 | smtp_data_timeout_exit(); | |
2726 | if (had_data_sigint) | |
2727 | smtp_data_sigint_exit(); | |
0d81dabc JH |
2728 | |
2729 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
2730 | closed down, not that the socket itself has been closed down. Revert to | |
2731 | non-SSL handling. */ | |
2732 | ||
74f1a423 | 2733 | switch(error) |
0d81dabc | 2734 | { |
74f1a423 JH |
2735 | case SSL_ERROR_NONE: |
2736 | break; | |
2737 | ||
2738 | case SSL_ERROR_ZERO_RETURN: | |
2739 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
0d81dabc | 2740 | |
74f1a423 JH |
2741 | receive_getc = smtp_getc; |
2742 | receive_getbuf = smtp_getbuf; | |
2743 | receive_get_cache = smtp_get_cache; | |
2744 | receive_ungetc = smtp_ungetc; | |
2745 | receive_feof = smtp_feof; | |
2746 | receive_ferror = smtp_ferror; | |
2747 | receive_smtp_buffered = smtp_buffered; | |
0d81dabc | 2748 | |
74f1a423 JH |
2749 | if (SSL_get_shutdown(server_ssl) == SSL_RECEIVED_SHUTDOWN) |
2750 | SSL_shutdown(server_ssl); | |
dec766a1 | 2751 | |
37f0ce65 | 2752 | #ifndef DISABLE_OCSP |
74f1a423 JH |
2753 | sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free); |
2754 | server_static_cbinfo->verify_stack = NULL; | |
37f0ce65 | 2755 | #endif |
74f1a423 JH |
2756 | SSL_free(server_ssl); |
2757 | SSL_CTX_free(server_ctx); | |
2758 | server_ctx = NULL; | |
2759 | server_ssl = NULL; | |
2760 | tls_in.active.sock = -1; | |
2761 | tls_in.active.tls_ctx = NULL; | |
2762 | tls_in.bits = 0; | |
2763 | tls_in.cipher = NULL; | |
2764 | tls_in.peerdn = NULL; | |
2765 | tls_in.sni = NULL; | |
0d81dabc | 2766 | |
74f1a423 | 2767 | return FALSE; |
0d81dabc | 2768 | |
74f1a423 JH |
2769 | /* Handle genuine errors */ |
2770 | case SSL_ERROR_SSL: | |
0abc5a13 | 2771 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
74f1a423 JH |
2772 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
2773 | ssl_xfer_error = TRUE; | |
2774 | return FALSE; | |
0d81dabc | 2775 | |
74f1a423 JH |
2776 | default: |
2777 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
2778 | DEBUG(D_tls) if (error == SSL_ERROR_SYSCALL) | |
2779 | debug_printf(" - syscall %s\n", strerror(errno)); | |
2780 | ssl_xfer_error = TRUE; | |
2781 | return FALSE; | |
0d81dabc JH |
2782 | } |
2783 | ||
2784 | #ifndef DISABLE_DKIM | |
2785 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
2786 | #endif | |
2787 | ssl_xfer_buffer_hwm = inbytes; | |
2788 | ssl_xfer_buffer_lwm = 0; | |
2789 | return TRUE; | |
2790 | } | |
2791 | ||
2792 | ||
059ec3d9 PH |
2793 | /************************************************* |
2794 | * TLS version of getc * | |
2795 | *************************************************/ | |
2796 | ||
2797 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2798 | it refills the buffer via the SSL reading function. | |
2799 | ||
bd8fbe36 | 2800 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 | 2801 | Returns: the next character or EOF |
817d9f57 JH |
2802 | |
2803 | Only used by the server-side TLS. | |
059ec3d9 PH |
2804 | */ |
2805 | ||
2806 | int | |
bd8fbe36 | 2807 | tls_getc(unsigned lim) |
059ec3d9 PH |
2808 | { |
2809 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
0d81dabc JH |
2810 | if (!tls_refill(lim)) |
2811 | return ssl_xfer_error ? EOF : smtp_getc(lim); | |
059ec3d9 | 2812 | |
0d81dabc | 2813 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2814 | |
0d81dabc JH |
2815 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; |
2816 | } | |
059ec3d9 | 2817 | |
0d81dabc JH |
2818 | uschar * |
2819 | tls_getbuf(unsigned * len) | |
2820 | { | |
2821 | unsigned size; | |
2822 | uschar * buf; | |
ba084640 | 2823 | |
0d81dabc JH |
2824 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) |
2825 | if (!tls_refill(*len)) | |
059ec3d9 | 2826 | { |
0d81dabc JH |
2827 | if (!ssl_xfer_error) return smtp_getbuf(len); |
2828 | *len = 0; | |
2829 | return NULL; | |
059ec3d9 | 2830 | } |
c80c5570 | 2831 | |
0d81dabc JH |
2832 | if ((size = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm) > *len) |
2833 | size = *len; | |
2834 | buf = &ssl_xfer_buffer[ssl_xfer_buffer_lwm]; | |
2835 | ssl_xfer_buffer_lwm += size; | |
2836 | *len = size; | |
2837 | return buf; | |
059ec3d9 PH |
2838 | } |
2839 | ||
0d81dabc | 2840 | |
584e96c6 JH |
2841 | void |
2842 | tls_get_cache() | |
2843 | { | |
9960d1e5 | 2844 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2845 | int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm; |
2846 | if (n > 0) | |
2847 | dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n); | |
584e96c6 | 2848 | #endif |
9960d1e5 | 2849 | } |
584e96c6 | 2850 | |
059ec3d9 | 2851 | |
925ac8e4 JH |
2852 | BOOL |
2853 | tls_could_read(void) | |
2854 | { | |
a5ffa9b4 | 2855 | return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(server_ssl) > 0; |
925ac8e4 JH |
2856 | } |
2857 | ||
059ec3d9 PH |
2858 | |
2859 | /************************************************* | |
2860 | * Read bytes from TLS channel * | |
2861 | *************************************************/ | |
2862 | ||
2863 | /* | |
2864 | Arguments: | |
74f1a423 | 2865 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2866 | buff buffer of data |
2867 | len size of buffer | |
2868 | ||
2869 | Returns: the number of bytes read | |
afdb5e9c | 2870 | -1 after a failed read, including EOF |
817d9f57 JH |
2871 | |
2872 | Only used by the client-side TLS. | |
059ec3d9 PH |
2873 | */ |
2874 | ||
2875 | int | |
74f1a423 | 2876 | tls_read(void * ct_ctx, uschar *buff, size_t len) |
059ec3d9 | 2877 | { |
74f1a423 | 2878 | SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; |
059ec3d9 PH |
2879 | int inbytes; |
2880 | int error; | |
2881 | ||
389ca47a | 2882 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 2883 | buff, (unsigned int)len); |
059ec3d9 | 2884 | |
389ca47a JH |
2885 | inbytes = SSL_read(ssl, CS buff, len); |
2886 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
2887 | |
2888 | if (error == SSL_ERROR_ZERO_RETURN) | |
2889 | { | |
2890 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
2891 | return -1; | |
2892 | } | |
2893 | else if (error != SSL_ERROR_NONE) | |
059ec3d9 | 2894 | return -1; |
059ec3d9 PH |
2895 | |
2896 | return inbytes; | |
2897 | } | |
2898 | ||
2899 | ||
2900 | ||
2901 | ||
2902 | ||
2903 | /************************************************* | |
2904 | * Write bytes down TLS channel * | |
2905 | *************************************************/ | |
2906 | ||
2907 | /* | |
2908 | Arguments: | |
74f1a423 | 2909 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2910 | buff buffer of data |
2911 | len number of bytes | |
925ac8e4 | 2912 | more further data expected soon |
059ec3d9 PH |
2913 | |
2914 | Returns: the number of bytes after a successful write, | |
2915 | -1 after a failed write | |
817d9f57 JH |
2916 | |
2917 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
2918 | */ |
2919 | ||
2920 | int | |
74f1a423 | 2921 | tls_write(void * ct_ctx, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2922 | { |
ac35befe | 2923 | size_t olen = len; |
d7978c0f | 2924 | int outbytes, error; |
74f1a423 | 2925 | SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; |
acec9514 | 2926 | static gstring * corked = NULL; |
a5ffa9b4 | 2927 | |
ef698bf6 | 2928 | DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__, |
b93be52e | 2929 | buff, (unsigned long)len, more ? ", more" : ""); |
a5ffa9b4 JH |
2930 | |
2931 | /* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when | |
2932 | "more" is notified. This hack is only ok if small amounts are involved AND only | |
2933 | one stream does it, in one context (i.e. no store reset). Currently it is used | |
2934 | for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. */ | |
ac35befe JH |
2935 | /* + if PIPE_COMMAND, banner & ehlo-resp for smmtp-on-connect. Suspect there's |
2936 | a store reset there, so use POOL_PERM. */ | |
2937 | /* + if CHUNKING, cmds EHLO,MAIL,RCPT(s),BDAT */ | |
a5ffa9b4 | 2938 | |
ac35befe | 2939 | if ((more || corked)) |
a5ffa9b4 | 2940 | { |
ee8b8090 JH |
2941 | #ifdef EXPERIMENTAL_PIPE_CONNECT |
2942 | int save_pool = store_pool; | |
2943 | store_pool = POOL_PERM; | |
2944 | #endif | |
2945 | ||
acec9514 | 2946 | corked = string_catn(corked, buff, len); |
ee8b8090 JH |
2947 | |
2948 | #ifdef EXPERIMENTAL_PIPE_CONNECT | |
2949 | store_pool = save_pool; | |
2950 | #endif | |
2951 | ||
a5ffa9b4 JH |
2952 | if (more) |
2953 | return len; | |
acec9514 JH |
2954 | buff = CUS corked->s; |
2955 | len = corked->ptr; | |
2956 | corked = NULL; | |
a5ffa9b4 | 2957 | } |
059ec3d9 | 2958 | |
d7978c0f | 2959 | for (int left = len; left > 0;) |
059ec3d9 | 2960 | { |
74f1a423 | 2961 | DEBUG(D_tls) debug_printf("SSL_write(%p, %p, %d)\n", ssl, buff, left); |
059ec3d9 PH |
2962 | outbytes = SSL_write(ssl, CS buff, left); |
2963 | error = SSL_get_error(ssl, outbytes); | |
2964 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
2965 | switch (error) | |
2966 | { | |
2967 | case SSL_ERROR_SSL: | |
0abc5a13 | 2968 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
96f5fe4c JH |
2969 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); |
2970 | return -1; | |
059ec3d9 PH |
2971 | |
2972 | case SSL_ERROR_NONE: | |
96f5fe4c JH |
2973 | left -= outbytes; |
2974 | buff += outbytes; | |
2975 | break; | |
059ec3d9 PH |
2976 | |
2977 | case SSL_ERROR_ZERO_RETURN: | |
96f5fe4c JH |
2978 | log_write(0, LOG_MAIN, "SSL channel closed on write"); |
2979 | return -1; | |
059ec3d9 | 2980 | |
817d9f57 | 2981 | case SSL_ERROR_SYSCALL: |
96f5fe4c JH |
2982 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", |
2983 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
2984 | strerror(errno)); | |
2985 | return -1; | |
817d9f57 | 2986 | |
059ec3d9 | 2987 | default: |
96f5fe4c JH |
2988 | log_write(0, LOG_MAIN, "SSL_write error %d", error); |
2989 | return -1; | |
059ec3d9 PH |
2990 | } |
2991 | } | |
ac35befe | 2992 | return olen; |
059ec3d9 PH |
2993 | } |
2994 | ||
2995 | ||
2996 | ||
2997 | /************************************************* | |
2998 | * Close down a TLS session * | |
2999 | *************************************************/ | |
3000 | ||
3001 | /* This is also called from within a delivery subprocess forked from the | |
3002 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
3003 | would tamper with the SSL session in the parent process). | |
3004 | ||
dec766a1 | 3005 | Arguments: |
74f1a423 | 3006 | ct_ctx client TLS context pointer, or NULL for the one global server context |
dec766a1 WB |
3007 | shutdown 1 if TLS close-alert is to be sent, |
3008 | 2 if also response to be waited for | |
3009 | ||
059ec3d9 | 3010 | Returns: nothing |
817d9f57 JH |
3011 | |
3012 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
3013 | */ |
3014 | ||
3015 | void | |
74f1a423 | 3016 | tls_close(void * ct_ctx, int shutdown) |
059ec3d9 | 3017 | { |
74f1a423 JH |
3018 | exim_openssl_client_tls_ctx * o_ctx = ct_ctx; |
3019 | SSL_CTX **ctxp = o_ctx ? &o_ctx->ctx : &server_ctx; | |
3020 | SSL **sslp = o_ctx ? &o_ctx->ssl : &server_ssl; | |
3021 | int *fdp = o_ctx ? &tls_out.active.sock : &tls_in.active.sock; | |
817d9f57 JH |
3022 | |
3023 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
3024 | |
3025 | if (shutdown) | |
3026 | { | |
dec766a1 WB |
3027 | int rc; |
3028 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", | |
3029 | shutdown > 1 ? " (with response-wait)" : ""); | |
3030 | ||
3031 | if ( (rc = SSL_shutdown(*sslp)) == 0 /* send "close notify" alert */ | |
3032 | && shutdown > 1) | |
3033 | { | |
c2a1bba0 | 3034 | ALARM(2); |
dec766a1 | 3035 | rc = SSL_shutdown(*sslp); /* wait for response */ |
c2a1bba0 | 3036 | ALARM_CLR(0); |
dec766a1 WB |
3037 | } |
3038 | ||
3039 | if (rc < 0) DEBUG(D_tls) | |
3040 | { | |
0abc5a13 | 3041 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
dec766a1 WB |
3042 | debug_printf("SSL_shutdown: %s\n", ssl_errstring); |
3043 | } | |
3044 | } | |
3045 | ||
37f0ce65 | 3046 | #ifndef DISABLE_OCSP |
74f1a423 | 3047 | if (!o_ctx) /* server side */ |
dec766a1 WB |
3048 | { |
3049 | sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free); | |
dec766a1 | 3050 | server_static_cbinfo->verify_stack = NULL; |
059ec3d9 | 3051 | } |
37f0ce65 | 3052 | #endif |
059ec3d9 | 3053 | |
dec766a1 | 3054 | SSL_CTX_free(*ctxp); |
817d9f57 | 3055 | SSL_free(*sslp); |
dec766a1 | 3056 | *ctxp = NULL; |
817d9f57 | 3057 | *sslp = NULL; |
817d9f57 | 3058 | *fdp = -1; |
059ec3d9 PH |
3059 | } |
3060 | ||
36f12725 NM |
3061 | |
3062 | ||
3063 | ||
3375e053 PP |
3064 | /************************************************* |
3065 | * Let tls_require_ciphers be checked at startup * | |
3066 | *************************************************/ | |
3067 | ||
3068 | /* The tls_require_ciphers option, if set, must be something which the | |
3069 | library can parse. | |
3070 | ||
3071 | Returns: NULL on success, or error message | |
3072 | */ | |
3073 | ||
3074 | uschar * | |
3075 | tls_validate_require_cipher(void) | |
3076 | { | |
3077 | SSL_CTX *ctx; | |
3078 | uschar *s, *expciphers, *err; | |
3079 | ||
3080 | /* this duplicates from tls_init(), we need a better "init just global | |
3081 | state, for no specific purpose" singleton function of our own */ | |
3082 | ||
7434882d | 3083 | #ifdef EXIM_NEED_OPENSSL_INIT |
3375e053 PP |
3084 | SSL_load_error_strings(); |
3085 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 3086 | #endif |
3375e053 PP |
3087 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
3088 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
3089 | list of available digests. */ | |
3090 | EVP_add_digest(EVP_sha256()); | |
3091 | #endif | |
3092 | ||
3093 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
3094 | return NULL; | |
3095 | ||
cf0c6164 JH |
3096 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
3097 | &err)) | |
3375e053 PP |
3098 | return US"failed to expand tls_require_ciphers"; |
3099 | ||
3100 | if (!(expciphers && *expciphers)) | |
3101 | return NULL; | |
3102 | ||
3103 | /* normalisation ripped from above */ | |
3104 | s = expciphers; | |
3105 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
3106 | ||
3107 | err = NULL; | |
3108 | ||
7a8b9519 JH |
3109 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
3110 | if (!(ctx = SSL_CTX_new(TLS_server_method()))) | |
3111 | #else | |
3112 | if (!(ctx = SSL_CTX_new(SSLv23_server_method()))) | |
3113 | #endif | |
3375e053 | 3114 | { |
0abc5a13 | 3115 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3375e053 PP |
3116 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); |
3117 | } | |
3118 | ||
3119 | DEBUG(D_tls) | |
3120 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
3121 | ||
3122 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
3123 | { | |
0abc5a13 | 3124 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 JH |
3125 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s", |
3126 | expciphers, ssl_errstring); | |
3375e053 PP |
3127 | } |
3128 | ||
3129 | SSL_CTX_free(ctx); | |
3130 | ||
3131 | return err; | |
3132 | } | |
3133 | ||
3134 | ||
3135 | ||
3136 | ||
36f12725 NM |
3137 | /************************************************* |
3138 | * Report the library versions. * | |
3139 | *************************************************/ | |
3140 | ||
3141 | /* There have historically been some issues with binary compatibility in | |
3142 | OpenSSL libraries; if Exim (like many other applications) is built against | |
3143 | one version of OpenSSL but the run-time linker picks up another version, | |
3144 | it can result in serious failures, including crashing with a SIGSEGV. So | |
3145 | report the version found by the compiler and the run-time version. | |
3146 | ||
f64a1e23 PP |
3147 | Note: some OS vendors backport security fixes without changing the version |
3148 | number/string, and the version date remains unchanged. The _build_ date | |
3149 | will change, so we can more usefully assist with version diagnosis by also | |
3150 | reporting the build date. | |
3151 | ||
36f12725 NM |
3152 | Arguments: a FILE* to print the results to |
3153 | Returns: nothing | |
3154 | */ | |
3155 | ||
3156 | void | |
3157 | tls_version_report(FILE *f) | |
3158 | { | |
754a0503 | 3159 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
3160 | " Runtime: %s\n" |
3161 | " : %s\n", | |
754a0503 | 3162 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
3163 | SSLeay_version(SSLEAY_VERSION), |
3164 | SSLeay_version(SSLEAY_BUILT_ON)); | |
3165 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
3166 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
3167 | } |
3168 | ||
9e3331ea TK |
3169 | |
3170 | ||
3171 | ||
3172 | /************************************************* | |
17c76198 | 3173 | * Random number generation * |
9e3331ea TK |
3174 | *************************************************/ |
3175 | ||
3176 | /* Pseudo-random number generation. The result is not expected to be | |
3177 | cryptographically strong but not so weak that someone will shoot themselves | |
3178 | in the foot using it as a nonce in input in some email header scheme or | |
3179 | whatever weirdness they'll twist this into. The result should handle fork() | |
3180 | and avoid repeating sequences. OpenSSL handles that for us. | |
3181 | ||
3182 | Arguments: | |
3183 | max range maximum | |
3184 | Returns a random number in range [0, max-1] | |
3185 | */ | |
3186 | ||
3187 | int | |
17c76198 | 3188 | vaguely_random_number(int max) |
9e3331ea TK |
3189 | { |
3190 | unsigned int r; | |
3191 | int i, needed_len; | |
de6135a0 PP |
3192 | static pid_t pidlast = 0; |
3193 | pid_t pidnow; | |
9e3331ea TK |
3194 | uschar smallbuf[sizeof(r)]; |
3195 | ||
3196 | if (max <= 1) | |
3197 | return 0; | |
3198 | ||
de6135a0 PP |
3199 | pidnow = getpid(); |
3200 | if (pidnow != pidlast) | |
3201 | { | |
3202 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
3203 | is unique for each thread", this doesn't apparently apply across processes, | |
3204 | so our own warning from vaguely_random_number_fallback() applies here too. | |
3205 | Fix per PostgreSQL. */ | |
3206 | if (pidlast != 0) | |
3207 | RAND_cleanup(); | |
3208 | pidlast = pidnow; | |
3209 | } | |
3210 | ||
9e3331ea TK |
3211 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
3212 | if (!RAND_status()) | |
3213 | { | |
3214 | randstuff r; | |
3215 | gettimeofday(&r.tv, NULL); | |
3216 | r.p = getpid(); | |
3217 | ||
5903c6ff | 3218 | RAND_seed(US (&r), sizeof(r)); |
9e3331ea TK |
3219 | } |
3220 | /* We're after pseudo-random, not random; if we still don't have enough data | |
3221 | in the internal PRNG then our options are limited. We could sleep and hope | |
3222 | for entropy to come along (prayer technique) but if the system is so depleted | |
3223 | in the first place then something is likely to just keep taking it. Instead, | |
3224 | we'll just take whatever little bit of pseudo-random we can still manage to | |
3225 | get. */ | |
3226 | ||
3227 | needed_len = sizeof(r); | |
3228 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
3229 | asked for a number less than 10. */ | |
3230 | for (r = max, i = 0; r; ++i) | |
3231 | r >>= 1; | |
3232 | i = (i + 7) / 8; | |
3233 | if (i < needed_len) | |
3234 | needed_len = i; | |
3235 | ||
c8dfb21d | 3236 | #ifdef EXIM_HAVE_RAND_PSEUDO |
9e3331ea | 3237 | /* We do not care if crypto-strong */ |
17c76198 | 3238 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
c8dfb21d JH |
3239 | #else |
3240 | i = RAND_bytes(smallbuf, needed_len); | |
3241 | #endif | |
3242 | ||
17c76198 PP |
3243 | if (i < 0) |
3244 | { | |
3245 | DEBUG(D_all) | |
3246 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
3247 | return vaguely_random_number_fallback(max); | |
3248 | } | |
3249 | ||
9e3331ea | 3250 | r = 0; |
d7978c0f JH |
3251 | for (uschar * p = smallbuf; needed_len; --needed_len, ++p) |
3252 | r = 256 * r + *p; | |
9e3331ea TK |
3253 | |
3254 | /* We don't particularly care about weighted results; if someone wants | |
3255 | smooth distribution and cares enough then they should submit a patch then. */ | |
3256 | return r % max; | |
3257 | } | |
3258 | ||
77bb000f PP |
3259 | |
3260 | ||
3261 | ||
3262 | /************************************************* | |
3263 | * OpenSSL option parse * | |
3264 | *************************************************/ | |
3265 | ||
3266 | /* Parse one option for tls_openssl_options_parse below | |
3267 | ||
3268 | Arguments: | |
3269 | name one option name | |
3270 | value place to store a value for it | |
3271 | Returns success or failure in parsing | |
3272 | */ | |
3273 | ||
77bb000f | 3274 | |
c80c5570 | 3275 | |
77bb000f PP |
3276 | static BOOL |
3277 | tls_openssl_one_option_parse(uschar *name, long *value) | |
3278 | { | |
3279 | int first = 0; | |
3280 | int last = exim_openssl_options_size; | |
3281 | while (last > first) | |
3282 | { | |
3283 | int middle = (first + last)/2; | |
3284 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
3285 | if (c == 0) | |
3286 | { | |
3287 | *value = exim_openssl_options[middle].value; | |
3288 | return TRUE; | |
3289 | } | |
3290 | else if (c > 0) | |
3291 | first = middle + 1; | |
3292 | else | |
3293 | last = middle; | |
3294 | } | |
3295 | return FALSE; | |
3296 | } | |
3297 | ||
3298 | ||
3299 | ||
3300 | ||
3301 | /************************************************* | |
3302 | * OpenSSL option parsing logic * | |
3303 | *************************************************/ | |
3304 | ||
3305 | /* OpenSSL has a number of compatibility options which an administrator might | |
3306 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
3307 | we look like log_selector. | |
3308 | ||
3309 | Arguments: | |
3310 | option_spec the administrator-supplied string of options | |
3311 | results ptr to long storage for the options bitmap | |
3312 | Returns success or failure | |
3313 | */ | |
3314 | ||
3315 | BOOL | |
3316 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
3317 | { | |
3318 | long result, item; | |
d7978c0f | 3319 | uschar *end; |
77bb000f PP |
3320 | uschar keep_c; |
3321 | BOOL adding, item_parsed; | |
3322 | ||
7006ee24 | 3323 | result = SSL_OP_NO_TICKET; |
b1770b6e | 3324 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 3325 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
3326 | #ifdef SSL_OP_NO_SSLv2 |
3327 | result |= SSL_OP_NO_SSLv2; | |
3328 | #endif | |
a57b6200 JH |
3329 | #ifdef SSL_OP_SINGLE_DH_USE |
3330 | result |= SSL_OP_SINGLE_DH_USE; | |
3331 | #endif | |
77bb000f | 3332 | |
7006ee24 | 3333 | if (!option_spec) |
77bb000f PP |
3334 | { |
3335 | *results = result; | |
3336 | return TRUE; | |
3337 | } | |
3338 | ||
d7978c0f | 3339 | for (uschar * s = option_spec; *s != '\0'; /**/) |
77bb000f PP |
3340 | { |
3341 | while (isspace(*s)) ++s; | |
3342 | if (*s == '\0') | |
3343 | break; | |
3344 | if (*s != '+' && *s != '-') | |
3345 | { | |
3346 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 3347 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
3348 | return FALSE; |
3349 | } | |
3350 | adding = *s++ == '+'; | |
3351 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
3352 | keep_c = *end; | |
3353 | *end = '\0'; | |
3354 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
96f5fe4c | 3355 | *end = keep_c; |
77bb000f PP |
3356 | if (!item_parsed) |
3357 | { | |
0e944a0d | 3358 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
3359 | return FALSE; |
3360 | } | |
3361 | DEBUG(D_tls) debug_printf("openssl option, %s from %lx: %lx (%s)\n", | |
3362 | adding ? "adding" : "removing", result, item, s); | |
3363 | if (adding) | |
3364 | result |= item; | |
3365 | else | |
3366 | result &= ~item; | |
77bb000f PP |
3367 | s = end; |
3368 | } | |
3369 | ||
3370 | *results = result; | |
3371 | return TRUE; | |
3372 | } | |
3373 | ||
8442641e | 3374 | #endif /*!MACRO_PREDEF*/ |
9d1c15ef JH |
3375 | /* vi: aw ai sw=2 |
3376 | */ | |
059ec3d9 | 3377 | /* End of tls-openssl.c */ |