Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
b10c87b3 | 5 | /* Copyright (c) University of Cambridge 1995 - 2019 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
f5d78688 JH |
8 | /* Portions Copyright (c) The OpenSSL Project 1999 */ |
9 | ||
059ec3d9 PH |
10 | /* This module provides the TLS (aka SSL) support for Exim using the OpenSSL |
11 | library. It is #included into the tls.c file when that library is used. The | |
12 | code herein is based on a patch that was originally contributed by Steve | |
13 | Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara. | |
14 | ||
15 | No cryptographic code is included in Exim. All this module does is to call | |
16 | functions from the OpenSSL library. */ | |
17 | ||
18 | ||
19 | /* Heading stuff */ | |
20 | ||
21 | #include <openssl/lhash.h> | |
22 | #include <openssl/ssl.h> | |
23 | #include <openssl/err.h> | |
24 | #include <openssl/rand.h> | |
10ca4f1c JH |
25 | #ifndef OPENSSL_NO_ECDH |
26 | # include <openssl/ec.h> | |
27 | #endif | |
f2de3a33 | 28 | #ifndef DISABLE_OCSP |
e51c7be2 | 29 | # include <openssl/ocsp.h> |
3f7eeb86 | 30 | #endif |
c0635b6d | 31 | #ifdef SUPPORT_DANE |
05e796ad | 32 | # include "danessl.h" |
85098ee7 JH |
33 | #endif |
34 | ||
3f7eeb86 | 35 | |
f2de3a33 JH |
36 | #ifndef DISABLE_OCSP |
37 | # define EXIM_OCSP_SKEW_SECONDS (300L) | |
38 | # define EXIM_OCSP_MAX_AGE (-1L) | |
3f7eeb86 | 39 | #endif |
059ec3d9 | 40 | |
3bcbbbe2 | 41 | #if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) |
e51c7be2 | 42 | # define EXIM_HAVE_OPENSSL_TLSEXT |
3bcbbbe2 | 43 | #endif |
c8dfb21d JH |
44 | #if OPENSSL_VERSION_NUMBER >= 0x00908000L |
45 | # define EXIM_HAVE_RSA_GENKEY_EX | |
46 | #endif | |
47 | #if OPENSSL_VERSION_NUMBER >= 0x10100000L | |
48 | # define EXIM_HAVE_OCSP_RESP_COUNT | |
49 | #else | |
50 | # define EXIM_HAVE_EPHEM_RSA_KEX | |
51 | # define EXIM_HAVE_RAND_PSEUDO | |
52 | #endif | |
53 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) | |
8442641e | 54 | # define EXIM_HAVE_SHA256 |
c8dfb21d | 55 | #endif |
34e3241d | 56 | |
d7978c0f JH |
57 | /* X509_check_host provides sane certificate hostname checking, but was added |
58 | to OpenSSL late, after other projects forked off the code-base. So in | |
59 | addition to guarding against the base version number, beware that LibreSSL | |
60 | does not (at this time) support this function. | |
61 | ||
62 | If LibreSSL gains a different API, perhaps via libtls, then we'll probably | |
63 | opt to disentangle and ask a LibreSSL user to provide glue for a third | |
64 | crypto provider for libtls instead of continuing to tie the OpenSSL glue | |
65 | into even twistier knots. If LibreSSL gains the same API, we can just | |
66 | change this guard and punt the issue for a while longer. */ | |
67 | ||
34e3241d PP |
68 | #ifndef LIBRESSL_VERSION_NUMBER |
69 | # if OPENSSL_VERSION_NUMBER >= 0x010100000L | |
70 | # define EXIM_HAVE_OPENSSL_CHECKHOST | |
8420742d | 71 | # define EXIM_HAVE_OPENSSL_DH_BITS |
7a8b9519 | 72 | # define EXIM_HAVE_OPENSSL_TLS_METHOD |
f20cfa4a | 73 | # define EXIM_HAVE_OPENSSL_KEYLOG |
f1be21cf | 74 | # define EXIM_HAVE_OPENSSL_CIPHER_GET_ID |
b10c87b3 | 75 | # define EXIM_HAVE_SESSION_TICKET |
e570d136 | 76 | # define EXIM_HAVE_OPESSL_TRACE |
7434882d JH |
77 | # else |
78 | # define EXIM_NEED_OPENSSL_INIT | |
34e3241d PP |
79 | # endif |
80 | # if OPENSSL_VERSION_NUMBER >= 0x010000000L \ | |
2dfb468b | 81 | && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L |
34e3241d PP |
82 | # define EXIM_HAVE_OPENSSL_CHECKHOST |
83 | # endif | |
11aa88b0 | 84 | #endif |
10ca4f1c | 85 | |
11aa88b0 RA |
86 | #if !defined(LIBRESSL_VERSION_NUMBER) \ |
87 | || LIBRESSL_VERSION_NUMBER >= 0x20010000L | |
10ca4f1c JH |
88 | # if !defined(OPENSSL_NO_ECDH) |
89 | # if OPENSSL_VERSION_NUMBER >= 0x0090800fL | |
8442641e | 90 | # define EXIM_HAVE_ECDH |
10ca4f1c JH |
91 | # endif |
92 | # if OPENSSL_VERSION_NUMBER >= 0x10002000L | |
10ca4f1c JH |
93 | # define EXIM_HAVE_OPENSSL_EC_NIST2NID |
94 | # endif | |
95 | # endif | |
2dfb468b | 96 | #endif |
3bcbbbe2 | 97 | |
8a40db1c JH |
98 | #ifndef LIBRESSL_VERSION_NUMBER |
99 | # if OPENSSL_VERSION_NUMBER >= 0x010101000L | |
100 | # define OPENSSL_HAVE_KEYLOG_CB | |
d7f31bb6 | 101 | # define OPENSSL_HAVE_NUM_TICKETS |
f1be21cf | 102 | # define EXIM_HAVE_OPENSSL_CIPHER_STD_NAME |
8a40db1c JH |
103 | # endif |
104 | #endif | |
105 | ||
67791ce4 JH |
106 | #if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP) |
107 | # warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile" | |
108 | # define DISABLE_OCSP | |
109 | #endif | |
43e2db44 JH |
110 | |
111 | #ifdef EXPERIMENTAL_TLS_RESUME | |
112 | # if OPENSSL_VERSION_NUMBER < 0x0101010L | |
113 | # error OpenSSL version too old for session-resumption | |
114 | # endif | |
115 | #endif | |
67791ce4 | 116 | |
a6510420 JH |
117 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
118 | # include <openssl/x509v3.h> | |
119 | #endif | |
120 | ||
f1be21cf JH |
121 | #ifndef EXIM_HAVE_OPENSSL_CIPHER_STD_NAME |
122 | # ifndef EXIM_HAVE_OPENSSL_CIPHER_GET_ID | |
123 | # define SSL_CIPHER_get_id(c) (c->id) | |
124 | # endif | |
dca6d121 JH |
125 | # ifndef MACRO_PREDEF |
126 | # include "tls-cipher-stdname.c" | |
127 | # endif | |
f1be21cf JH |
128 | #endif |
129 | ||
8442641e JH |
130 | /************************************************* |
131 | * OpenSSL option parse * | |
132 | *************************************************/ | |
133 | ||
134 | typedef struct exim_openssl_option { | |
135 | uschar *name; | |
136 | long value; | |
137 | } exim_openssl_option; | |
138 | /* We could use a macro to expand, but we need the ifdef and not all the | |
139 | options document which version they were introduced in. Policylet: include | |
140 | all options unless explicitly for DTLS, let the administrator choose which | |
141 | to apply. | |
142 | ||
143 | This list is current as of: | |
144 | ==> 1.0.1b <== | |
145 | Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev | |
146 | Plus SSL_OP_NO_TLSv1_3 for 1.1.2-dev | |
147 | */ | |
148 | static exim_openssl_option exim_openssl_options[] = { | |
149 | /* KEEP SORTED ALPHABETICALLY! */ | |
150 | #ifdef SSL_OP_ALL | |
6d95688d | 151 | { US"all", (long) SSL_OP_ALL }, |
8442641e JH |
152 | #endif |
153 | #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION | |
154 | { US"allow_unsafe_legacy_renegotiation", SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION }, | |
155 | #endif | |
156 | #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE | |
157 | { US"cipher_server_preference", SSL_OP_CIPHER_SERVER_PREFERENCE }, | |
158 | #endif | |
159 | #ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS | |
160 | { US"dont_insert_empty_fragments", SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS }, | |
161 | #endif | |
162 | #ifdef SSL_OP_EPHEMERAL_RSA | |
163 | { US"ephemeral_rsa", SSL_OP_EPHEMERAL_RSA }, | |
164 | #endif | |
165 | #ifdef SSL_OP_LEGACY_SERVER_CONNECT | |
166 | { US"legacy_server_connect", SSL_OP_LEGACY_SERVER_CONNECT }, | |
167 | #endif | |
168 | #ifdef SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER | |
169 | { US"microsoft_big_sslv3_buffer", SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER }, | |
170 | #endif | |
171 | #ifdef SSL_OP_MICROSOFT_SESS_ID_BUG | |
172 | { US"microsoft_sess_id_bug", SSL_OP_MICROSOFT_SESS_ID_BUG }, | |
173 | #endif | |
174 | #ifdef SSL_OP_MSIE_SSLV2_RSA_PADDING | |
175 | { US"msie_sslv2_rsa_padding", SSL_OP_MSIE_SSLV2_RSA_PADDING }, | |
176 | #endif | |
177 | #ifdef SSL_OP_NETSCAPE_CHALLENGE_BUG | |
178 | { US"netscape_challenge_bug", SSL_OP_NETSCAPE_CHALLENGE_BUG }, | |
179 | #endif | |
180 | #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG | |
181 | { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, | |
182 | #endif | |
183 | #ifdef SSL_OP_NO_COMPRESSION | |
184 | { US"no_compression", SSL_OP_NO_COMPRESSION }, | |
185 | #endif | |
186 | #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION | |
187 | { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, | |
188 | #endif | |
189 | #ifdef SSL_OP_NO_SSLv2 | |
190 | { US"no_sslv2", SSL_OP_NO_SSLv2 }, | |
191 | #endif | |
192 | #ifdef SSL_OP_NO_SSLv3 | |
193 | { US"no_sslv3", SSL_OP_NO_SSLv3 }, | |
194 | #endif | |
195 | #ifdef SSL_OP_NO_TICKET | |
196 | { US"no_ticket", SSL_OP_NO_TICKET }, | |
197 | #endif | |
198 | #ifdef SSL_OP_NO_TLSv1 | |
199 | { US"no_tlsv1", SSL_OP_NO_TLSv1 }, | |
200 | #endif | |
201 | #ifdef SSL_OP_NO_TLSv1_1 | |
202 | #if SSL_OP_NO_TLSv1_1 == 0x00000400L | |
203 | /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ | |
204 | #warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring | |
205 | #else | |
206 | { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, | |
207 | #endif | |
208 | #endif | |
209 | #ifdef SSL_OP_NO_TLSv1_2 | |
210 | { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, | |
211 | #endif | |
212 | #ifdef SSL_OP_NO_TLSv1_3 | |
213 | { US"no_tlsv1_3", SSL_OP_NO_TLSv1_3 }, | |
214 | #endif | |
215 | #ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG | |
216 | { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG }, | |
217 | #endif | |
218 | #ifdef SSL_OP_SINGLE_DH_USE | |
219 | { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, | |
220 | #endif | |
221 | #ifdef SSL_OP_SINGLE_ECDH_USE | |
222 | { US"single_ecdh_use", SSL_OP_SINGLE_ECDH_USE }, | |
223 | #endif | |
224 | #ifdef SSL_OP_SSLEAY_080_CLIENT_DH_BUG | |
225 | { US"ssleay_080_client_dh_bug", SSL_OP_SSLEAY_080_CLIENT_DH_BUG }, | |
226 | #endif | |
227 | #ifdef SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG | |
228 | { US"sslref2_reuse_cert_type_bug", SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG }, | |
229 | #endif | |
230 | #ifdef SSL_OP_TLS_BLOCK_PADDING_BUG | |
231 | { US"tls_block_padding_bug", SSL_OP_TLS_BLOCK_PADDING_BUG }, | |
232 | #endif | |
233 | #ifdef SSL_OP_TLS_D5_BUG | |
234 | { US"tls_d5_bug", SSL_OP_TLS_D5_BUG }, | |
235 | #endif | |
236 | #ifdef SSL_OP_TLS_ROLLBACK_BUG | |
237 | { US"tls_rollback_bug", SSL_OP_TLS_ROLLBACK_BUG }, | |
238 | #endif | |
239 | }; | |
240 | ||
241 | #ifndef MACRO_PREDEF | |
242 | static int exim_openssl_options_size = nelem(exim_openssl_options); | |
243 | #endif | |
244 | ||
245 | #ifdef MACRO_PREDEF | |
246 | void | |
247 | options_tls(void) | |
248 | { | |
8442641e JH |
249 | uschar buf[64]; |
250 | ||
d7978c0f | 251 | for (struct exim_openssl_option * o = exim_openssl_options; |
8442641e JH |
252 | o < exim_openssl_options + nelem(exim_openssl_options); o++) |
253 | { | |
254 | /* Trailing X is workaround for problem with _OPT_OPENSSL_NO_TLSV1 | |
255 | being a ".ifdef _OPT_OPENSSL_NO_TLSV1_3" match */ | |
256 | ||
257 | spf(buf, sizeof(buf), US"_OPT_OPENSSL_%T_X", o->name); | |
258 | builtin_macro_create(buf); | |
259 | } | |
b10c87b3 JH |
260 | |
261 | # ifdef EXPERIMENTAL_TLS_RESUME | |
262 | builtin_macro_create_var(US"_RESUME_DECODE", RESUME_DECODE_STRING ); | |
263 | # endif | |
8442641e JH |
264 | } |
265 | #else | |
266 | ||
267 | /******************************************************************************/ | |
268 | ||
059ec3d9 PH |
269 | /* Structure for collecting random data for seeding. */ |
270 | ||
271 | typedef struct randstuff { | |
9e3331ea TK |
272 | struct timeval tv; |
273 | pid_t p; | |
059ec3d9 PH |
274 | } randstuff; |
275 | ||
276 | /* Local static variables */ | |
277 | ||
a2ff477a JH |
278 | static BOOL client_verify_callback_called = FALSE; |
279 | static BOOL server_verify_callback_called = FALSE; | |
059ec3d9 PH |
280 | static const uschar *sid_ctx = US"exim"; |
281 | ||
d4f09789 PP |
282 | /* We have three different contexts to care about. |
283 | ||
284 | Simple case: client, `client_ctx` | |
285 | As a client, we can be doing a callout or cut-through delivery while receiving | |
286 | a message. So we have a client context, which should have options initialised | |
74f1a423 JH |
287 | from the SMTP Transport. We may also concurrently want to make TLS connections |
288 | to utility daemons, so client-contexts are allocated and passed around in call | |
289 | args rather than using a gobal. | |
d4f09789 PP |
290 | |
291 | Server: | |
292 | There are two cases: with and without ServerNameIndication from the client. | |
293 | Given TLS SNI, we can be using different keys, certs and various other | |
294 | configuration settings, because they're re-expanded with $tls_sni set. This | |
295 | allows vhosting with TLS. This SNI is sent in the handshake. | |
296 | A client might not send SNI, so we need a fallback, and an initial setup too. | |
297 | So as a server, we start out using `server_ctx`. | |
298 | If SNI is sent by the client, then we as server, mid-negotiation, try to clone | |
299 | `server_sni` from `server_ctx` and then initialise settings by re-expanding | |
300 | configuration. | |
301 | */ | |
302 | ||
74f1a423 JH |
303 | typedef struct { |
304 | SSL_CTX * ctx; | |
305 | SSL * ssl; | |
c09dbcfb | 306 | gstring * corked; |
74f1a423 JH |
307 | } exim_openssl_client_tls_ctx; |
308 | ||
817d9f57 | 309 | static SSL_CTX *server_ctx = NULL; |
817d9f57 | 310 | static SSL *server_ssl = NULL; |
389ca47a | 311 | |
35731706 | 312 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
817d9f57 | 313 | static SSL_CTX *server_sni = NULL; |
35731706 | 314 | #endif |
059ec3d9 PH |
315 | |
316 | static char ssl_errstring[256]; | |
317 | ||
dea4b568 | 318 | static int ssl_session_timeout = 7200; /* Two hours */ |
a2ff477a JH |
319 | static BOOL client_verify_optional = FALSE; |
320 | static BOOL server_verify_optional = FALSE; | |
059ec3d9 | 321 | |
f5d78688 | 322 | static BOOL reexpand_tls_files_for_sni = FALSE; |
059ec3d9 PH |
323 | |
324 | ||
7be682ca | 325 | typedef struct tls_ext_ctx_cb { |
b10c87b3 | 326 | tls_support * tlsp; |
7be682ca PP |
327 | uschar *certificate; |
328 | uschar *privatekey; | |
f5d78688 | 329 | BOOL is_server; |
a6510420 | 330 | #ifndef DISABLE_OCSP |
c3033f13 | 331 | STACK_OF(X509) *verify_stack; /* chain for verifying the proof */ |
f5d78688 JH |
332 | union { |
333 | struct { | |
334 | uschar *file; | |
335 | uschar *file_expanded; | |
336 | OCSP_RESPONSE *response; | |
337 | } server; | |
338 | struct { | |
44662487 JH |
339 | X509_STORE *verify_store; /* non-null if status requested */ |
340 | BOOL verify_required; | |
f5d78688 JH |
341 | } client; |
342 | } u_ocsp; | |
3f7eeb86 | 343 | #endif |
7be682ca PP |
344 | uschar *dhparam; |
345 | /* these are cached from first expand */ | |
346 | uschar *server_cipher_list; | |
347 | /* only passed down to tls_error: */ | |
348 | host_item *host; | |
55414b25 | 349 | const uschar * verify_cert_hostnames; |
0cbf2b82 | 350 | #ifndef DISABLE_EVENT |
a7538db1 JH |
351 | uschar * event_action; |
352 | #endif | |
7be682ca PP |
353 | } tls_ext_ctx_cb; |
354 | ||
355 | /* should figure out a cleanup of API to handle state preserved per | |
356 | implementation, for various reasons, which can be void * in the APIs. | |
357 | For now, we hack around it. */ | |
b10c87b3 | 358 | tls_ext_ctx_cb *client_static_cbinfo = NULL; /*XXX should not use static; multiple concurrent clients! */ |
817d9f57 | 359 | tls_ext_ctx_cb *server_static_cbinfo = NULL; |
7be682ca PP |
360 | |
361 | static int | |
983207c1 | 362 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 363 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr ); |
059ec3d9 | 364 | |
3f7eeb86 | 365 | /* Callbacks */ |
3bcbbbe2 | 366 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
3f7eeb86 | 367 | static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); |
3bcbbbe2 | 368 | #endif |
f2de3a33 | 369 | #ifndef DISABLE_OCSP |
f5d78688 | 370 | static int tls_server_stapling_cb(SSL *s, void *arg); |
3f7eeb86 PP |
371 | #endif |
372 | ||
059ec3d9 | 373 | |
b10c87b3 | 374 | |
4d93129f | 375 | /* Daemon-called, before every connection, key create/rotate */ |
b10c87b3 JH |
376 | #ifdef EXPERIMENTAL_TLS_RESUME |
377 | static void tk_init(void); | |
378 | static int tls_exdata_idx = -1; | |
379 | #endif | |
380 | ||
381 | void | |
382 | tls_daemon_init(void) | |
383 | { | |
384 | #ifdef EXPERIMENTAL_TLS_RESUME | |
385 | tk_init(); | |
386 | #endif | |
387 | return; | |
388 | } | |
389 | ||
390 | ||
059ec3d9 PH |
391 | /************************************************* |
392 | * Handle TLS error * | |
393 | *************************************************/ | |
394 | ||
395 | /* Called from lots of places when errors occur before actually starting to do | |
396 | the TLS handshake, that is, while the session is still in clear. Always returns | |
397 | DEFER for a server and FAIL for a client so that most calls can use "return | |
398 | tls_error(...)" to do this processing and then give an appropriate return. A | |
399 | single function is used for both server and client, because it is called from | |
400 | some shared functions. | |
401 | ||
402 | Argument: | |
403 | prefix text to include in the logged error | |
404 | host NULL if setting up a server; | |
405 | the connected host if setting up a client | |
7199e1ee | 406 | msg error message or NULL if we should ask OpenSSL |
cf0c6164 | 407 | errstr pointer to output error message |
059ec3d9 PH |
408 | |
409 | Returns: OK/DEFER/FAIL | |
410 | */ | |
411 | ||
412 | static int | |
cf0c6164 | 413 | tls_error(uschar * prefix, const host_item * host, uschar * msg, uschar ** errstr) |
059ec3d9 | 414 | { |
c562fd30 | 415 | if (!msg) |
7199e1ee | 416 | { |
0abc5a13 | 417 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 | 418 | msg = US ssl_errstring; |
7199e1ee TF |
419 | } |
420 | ||
5a2a0989 JH |
421 | msg = string_sprintf("(%s): %s", prefix, msg); |
422 | DEBUG(D_tls) debug_printf("TLS error '%s'\n", msg); | |
423 | if (errstr) *errstr = msg; | |
cf0c6164 | 424 | return host ? FAIL : DEFER; |
059ec3d9 PH |
425 | } |
426 | ||
427 | ||
428 | ||
429 | /************************************************* | |
430 | * Callback to generate RSA key * | |
431 | *************************************************/ | |
432 | ||
433 | /* | |
434 | Arguments: | |
3ae79556 | 435 | s SSL connection (not used) |
059ec3d9 PH |
436 | export not used |
437 | keylength keylength | |
438 | ||
439 | Returns: pointer to generated key | |
440 | */ | |
441 | ||
442 | static RSA * | |
443 | rsa_callback(SSL *s, int export, int keylength) | |
444 | { | |
445 | RSA *rsa_key; | |
c8dfb21d JH |
446 | #ifdef EXIM_HAVE_RSA_GENKEY_EX |
447 | BIGNUM *bn = BN_new(); | |
448 | #endif | |
449 | ||
059ec3d9 PH |
450 | export = export; /* Shut picky compilers up */ |
451 | DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); | |
c8dfb21d JH |
452 | |
453 | #ifdef EXIM_HAVE_RSA_GENKEY_EX | |
454 | if ( !BN_set_word(bn, (unsigned long)RSA_F4) | |
f2cb6292 | 455 | || !(rsa_key = RSA_new()) |
c8dfb21d JH |
456 | || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL) |
457 | ) | |
458 | #else | |
23bb6982 | 459 | if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL))) |
c8dfb21d JH |
460 | #endif |
461 | ||
059ec3d9 | 462 | { |
0abc5a13 | 463 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
059ec3d9 PH |
464 | log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s", |
465 | ssl_errstring); | |
466 | return NULL; | |
467 | } | |
468 | return rsa_key; | |
469 | } | |
470 | ||
471 | ||
472 | ||
f5d78688 | 473 | /* Extreme debug |
f2de3a33 | 474 | #ifndef DISABLE_OCSP |
f5d78688 JH |
475 | void |
476 | x509_store_dump_cert_s_names(X509_STORE * store) | |
477 | { | |
478 | STACK_OF(X509_OBJECT) * roots= store->objs; | |
f5d78688 JH |
479 | static uschar name[256]; |
480 | ||
d7978c0f | 481 | for (int i= 0; i < sk_X509_OBJECT_num(roots); i++) |
f5d78688 JH |
482 | { |
483 | X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i); | |
484 | if(tmp_obj->type == X509_LU_X509) | |
485 | { | |
70e384dd JH |
486 | X509_NAME * sn = X509_get_subject_name(tmp_obj->data.x509); |
487 | if (X509_NAME_oneline(sn, CS name, sizeof(name))) | |
488 | { | |
489 | name[sizeof(name)-1] = '\0'; | |
490 | debug_printf(" %s\n", name); | |
491 | } | |
f5d78688 JH |
492 | } |
493 | } | |
494 | } | |
495 | #endif | |
496 | */ | |
497 | ||
059ec3d9 | 498 | |
0cbf2b82 | 499 | #ifndef DISABLE_EVENT |
f69979cf JH |
500 | static int |
501 | verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn, | |
502 | BOOL *calledp, const BOOL *optionalp, const uschar * what) | |
503 | { | |
504 | uschar * ev; | |
505 | uschar * yield; | |
506 | X509 * old_cert; | |
507 | ||
508 | ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; | |
509 | if (ev) | |
510 | { | |
aaba7d03 | 511 | DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth); |
f69979cf JH |
512 | old_cert = tlsp->peercert; |
513 | tlsp->peercert = X509_dup(cert); | |
514 | /* NB we do not bother setting peerdn */ | |
515 | if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth)))) | |
516 | { | |
517 | log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: " | |
518 | "depth=%d cert=%s: %s", | |
519 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
520 | what, depth, dn, yield); | |
521 | *calledp = TRUE; | |
522 | if (!*optionalp) | |
523 | { | |
524 | if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */ | |
525 | return 1; /* reject (leaving peercert set) */ | |
526 | } | |
527 | DEBUG(D_tls) debug_printf("Event-action verify failure overridden " | |
528 | "(host in tls_try_verify_hosts)\n"); | |
4a1bd6b9 | 529 | tlsp->verify_override = TRUE; |
f69979cf JH |
530 | } |
531 | X509_free(tlsp->peercert); | |
532 | tlsp->peercert = old_cert; | |
533 | } | |
534 | return 0; | |
535 | } | |
536 | #endif | |
537 | ||
059ec3d9 PH |
538 | /************************************************* |
539 | * Callback for verification * | |
540 | *************************************************/ | |
541 | ||
542 | /* The SSL library does certificate verification if set up to do so. This | |
543 | callback has the current yes/no state is in "state". If verification succeeded, | |
f69979cf JH |
544 | we set the certificate-verified flag. If verification failed, what happens |
545 | depends on whether the client is required to present a verifiable certificate | |
546 | or not. | |
059ec3d9 PH |
547 | |
548 | If verification is optional, we change the state to yes, but still log the | |
549 | verification error. For some reason (it really would help to have proper | |
550 | documentation of OpenSSL), this callback function then gets called again, this | |
f69979cf JH |
551 | time with state = 1. We must take care not to set the private verified flag on |
552 | the second time through. | |
059ec3d9 PH |
553 | |
554 | Note: this function is not called if the client fails to present a certificate | |
555 | when asked. We get here only if a certificate has been received. Handling of | |
556 | optional verification for this case is done when requesting SSL to verify, by | |
557 | setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. | |
558 | ||
a7538db1 JH |
559 | May be called multiple times for different issues with a certificate, even |
560 | for a given "depth" in the certificate chain. | |
561 | ||
059ec3d9 | 562 | Arguments: |
f2f2c91b JH |
563 | preverify_ok current yes/no state as 1/0 |
564 | x509ctx certificate information. | |
565 | tlsp per-direction (client vs. server) support data | |
566 | calledp has-been-called flag | |
567 | optionalp verification-is-optional flag | |
059ec3d9 | 568 | |
f2f2c91b | 569 | Returns: 0 if verification should fail, otherwise 1 |
059ec3d9 PH |
570 | */ |
571 | ||
572 | static int | |
70e384dd JH |
573 | verify_callback(int preverify_ok, X509_STORE_CTX * x509ctx, |
574 | tls_support * tlsp, BOOL * calledp, BOOL * optionalp) | |
059ec3d9 | 575 | { |
421aff85 | 576 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); |
a7538db1 | 577 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
f69979cf | 578 | uschar dn[256]; |
059ec3d9 | 579 | |
70e384dd JH |
580 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
581 | { | |
582 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
583 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
584 | tlsp == &tls_out ? deliver_host_address : sender_host_address); | |
585 | return 0; | |
586 | } | |
f69979cf | 587 | dn[sizeof(dn)-1] = '\0'; |
059ec3d9 | 588 | |
f4e62a87 | 589 | tlsp->verify_override = FALSE; |
f2f2c91b | 590 | if (preverify_ok == 0) |
059ec3d9 | 591 | { |
f77197ae JH |
592 | uschar * extra = verify_mode ? string_sprintf(" (during %c-verify for [%s])", |
593 | *verify_mode, sender_host_address) | |
594 | : US""; | |
595 | log_write(0, LOG_MAIN, "[%s] SSL verify error%s: depth=%d error=%s cert=%s", | |
596 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
597 | extra, depth, | |
598 | X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), dn); | |
a2ff477a | 599 | *calledp = TRUE; |
9d1c15ef JH |
600 | if (!*optionalp) |
601 | { | |
f69979cf JH |
602 | if (!tlsp->peercert) |
603 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
604 | return 0; /* reject */ | |
9d1c15ef | 605 | } |
059ec3d9 PH |
606 | DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in " |
607 | "tls_try_verify_hosts)\n"); | |
4a1bd6b9 | 608 | tlsp->verify_override = TRUE; |
059ec3d9 PH |
609 | } |
610 | ||
a7538db1 | 611 | else if (depth != 0) |
059ec3d9 | 612 | { |
f69979cf | 613 | DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn); |
f2de3a33 | 614 | #ifndef DISABLE_OCSP |
f5d78688 JH |
615 | if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) |
616 | { /* client, wanting stapling */ | |
617 | /* Add the server cert's signing chain as the one | |
618 | for the verification of the OCSP stapled information. */ | |
94431adb | 619 | |
f5d78688 | 620 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, |
421aff85 | 621 | cert)) |
f5d78688 | 622 | ERR_clear_error(); |
c3033f13 | 623 | sk_X509_push(client_static_cbinfo->verify_stack, cert); |
f5d78688 | 624 | } |
a7538db1 | 625 | #endif |
0cbf2b82 | 626 | #ifndef DISABLE_EVENT |
f69979cf JH |
627 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
628 | return 0; /* reject, with peercert set */ | |
f5d78688 | 629 | #endif |
059ec3d9 PH |
630 | } |
631 | else | |
632 | { | |
55414b25 | 633 | const uschar * verify_cert_hostnames; |
e51c7be2 | 634 | |
e51c7be2 JH |
635 | if ( tlsp == &tls_out |
636 | && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames))) | |
afdb5e9c | 637 | /* client, wanting hostname check */ |
e51c7be2 | 638 | { |
f69979cf | 639 | |
740f36d4 | 640 | #ifdef EXIM_HAVE_OPENSSL_CHECKHOST |
f69979cf JH |
641 | # ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
642 | # define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0 | |
643 | # endif | |
644 | # ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS | |
645 | # define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0 | |
646 | # endif | |
e51c7be2 | 647 | int sep = 0; |
55414b25 | 648 | const uschar * list = verify_cert_hostnames; |
e51c7be2 | 649 | uschar * name; |
d8e7834a JH |
650 | int rc; |
651 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) | |
f40d5be3 | 652 | if ((rc = X509_check_host(cert, CCS name, 0, |
8d692470 | 653 | X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS |
740f36d4 JH |
654 | | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS, |
655 | NULL))) | |
d8e7834a JH |
656 | { |
657 | if (rc < 0) | |
658 | { | |
93a6fce2 | 659 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", |
f77197ae | 660 | tlsp == &tls_out ? deliver_host_address : sender_host_address); |
d8e7834a JH |
661 | name = NULL; |
662 | } | |
e51c7be2 | 663 | break; |
d8e7834a | 664 | } |
e51c7be2 | 665 | if (!name) |
f69979cf | 666 | #else |
e51c7be2 | 667 | if (!tls_is_name_for_cert(verify_cert_hostnames, cert)) |
f69979cf | 668 | #endif |
e51c7be2 | 669 | { |
f77197ae JH |
670 | uschar * extra = verify_mode |
671 | ? string_sprintf(" (during %c-verify for [%s])", | |
672 | *verify_mode, sender_host_address) | |
673 | : US""; | |
e51c7be2 | 674 | log_write(0, LOG_MAIN, |
f77197ae JH |
675 | "[%s] SSL verify error%s: certificate name mismatch: DN=\"%s\" H=\"%s\"", |
676 | tlsp == &tls_out ? deliver_host_address : sender_host_address, | |
677 | extra, dn, verify_cert_hostnames); | |
a3ef7310 JH |
678 | *calledp = TRUE; |
679 | if (!*optionalp) | |
f69979cf JH |
680 | { |
681 | if (!tlsp->peercert) | |
682 | tlsp->peercert = X509_dup(cert); /* record failing cert */ | |
683 | return 0; /* reject */ | |
684 | } | |
4a1bd6b9 | 685 | DEBUG(D_tls) debug_printf("SSL verify name failure overridden (host in " |
a3ef7310 | 686 | "tls_try_verify_hosts)\n"); |
4a1bd6b9 | 687 | tlsp->verify_override = TRUE; |
e51c7be2 | 688 | } |
f69979cf | 689 | } |
e51c7be2 | 690 | |
0cbf2b82 | 691 | #ifndef DISABLE_EVENT |
f69979cf JH |
692 | if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL")) |
693 | return 0; /* reject, with peercert set */ | |
e51c7be2 JH |
694 | #endif |
695 | ||
93dcb1c2 | 696 | DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", |
f69979cf | 697 | *calledp ? "" : " authenticated", dn); |
93dcb1c2 | 698 | *calledp = TRUE; |
059ec3d9 PH |
699 | } |
700 | ||
a7538db1 | 701 | return 1; /* accept, at least for this level */ |
059ec3d9 PH |
702 | } |
703 | ||
a2ff477a | 704 | static int |
f2f2c91b | 705 | verify_callback_client(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 706 | { |
f2f2c91b JH |
707 | return verify_callback(preverify_ok, x509ctx, &tls_out, |
708 | &client_verify_callback_called, &client_verify_optional); | |
a2ff477a JH |
709 | } |
710 | ||
711 | static int | |
f2f2c91b | 712 | verify_callback_server(int preverify_ok, X509_STORE_CTX *x509ctx) |
a2ff477a | 713 | { |
f2f2c91b JH |
714 | return verify_callback(preverify_ok, x509ctx, &tls_in, |
715 | &server_verify_callback_called, &server_verify_optional); | |
a2ff477a JH |
716 | } |
717 | ||
059ec3d9 | 718 | |
c0635b6d | 719 | #ifdef SUPPORT_DANE |
53a7196b | 720 | |
e5cccda9 JH |
721 | /* This gets called *by* the dane library verify callback, which interposes |
722 | itself. | |
723 | */ | |
724 | static int | |
f2f2c91b | 725 | verify_callback_client_dane(int preverify_ok, X509_STORE_CTX * x509ctx) |
e5cccda9 JH |
726 | { |
727 | X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); | |
f69979cf | 728 | uschar dn[256]; |
83b27293 | 729 | int depth = X509_STORE_CTX_get_error_depth(x509ctx); |
5c75db2e | 730 | #ifndef DISABLE_EVENT |
f69979cf | 731 | BOOL dummy_called, optional = FALSE; |
83b27293 | 732 | #endif |
e5cccda9 | 733 | |
70e384dd JH |
734 | if (!X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn))) |
735 | { | |
736 | DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); | |
737 | log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error", | |
738 | deliver_host_address); | |
739 | return 0; | |
740 | } | |
f69979cf | 741 | dn[sizeof(dn)-1] = '\0'; |
e5cccda9 | 742 | |
f2f2c91b JH |
743 | DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s depth %d %s\n", |
744 | preverify_ok ? "ok":"BAD", depth, dn); | |
e5cccda9 | 745 | |
0cbf2b82 | 746 | #ifndef DISABLE_EVENT |
f69979cf JH |
747 | if (verify_event(&tls_out, cert, depth, dn, |
748 | &dummy_called, &optional, US"DANE")) | |
749 | return 0; /* reject, with peercert set */ | |
83b27293 JH |
750 | #endif |
751 | ||
f2f2c91b | 752 | if (preverify_ok == 1) |
6fbf3599 | 753 | { |
4a1bd6b9 | 754 | tls_out.dane_verified = TRUE; |
6fbf3599 JH |
755 | #ifndef DISABLE_OCSP |
756 | if (client_static_cbinfo->u_ocsp.client.verify_store) | |
757 | { /* client, wanting stapling */ | |
758 | /* Add the server cert's signing chain as the one | |
759 | for the verification of the OCSP stapled information. */ | |
760 | ||
761 | if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store, | |
762 | cert)) | |
763 | ERR_clear_error(); | |
764 | sk_X509_push(client_static_cbinfo->verify_stack, cert); | |
765 | } | |
766 | #endif | |
767 | } | |
f2f2c91b JH |
768 | else |
769 | { | |
770 | int err = X509_STORE_CTX_get_error(x509ctx); | |
771 | DEBUG(D_tls) | |
772 | debug_printf(" - err %d '%s'\n", err, X509_verify_cert_error_string(err)); | |
3c51463e | 773 | if (err == X509_V_ERR_APPLICATION_VERIFICATION) |
f2f2c91b JH |
774 | preverify_ok = 1; |
775 | } | |
776 | return preverify_ok; | |
e5cccda9 | 777 | } |
53a7196b | 778 | |
c0635b6d | 779 | #endif /*SUPPORT_DANE*/ |
e5cccda9 | 780 | |
059ec3d9 PH |
781 | |
782 | /************************************************* | |
783 | * Information callback * | |
784 | *************************************************/ | |
785 | ||
786 | /* The SSL library functions call this from time to time to indicate what they | |
7be682ca PP |
787 | are doing. We copy the string to the debugging output when TLS debugging has |
788 | been requested. | |
059ec3d9 PH |
789 | |
790 | Arguments: | |
791 | s the SSL connection | |
792 | where | |
793 | ret | |
794 | ||
795 | Returns: nothing | |
796 | */ | |
797 | ||
798 | static void | |
799 | info_callback(SSL *s, int where, int ret) | |
800 | { | |
0abc5a13 JH |
801 | DEBUG(D_tls) |
802 | { | |
803 | const uschar * str; | |
804 | ||
805 | if (where & SSL_ST_CONNECT) | |
48224640 | 806 | str = US"SSL_connect"; |
0abc5a13 | 807 | else if (where & SSL_ST_ACCEPT) |
48224640 | 808 | str = US"SSL_accept"; |
0abc5a13 | 809 | else |
48224640 | 810 | str = US"SSL info (undefined)"; |
0abc5a13 JH |
811 | |
812 | if (where & SSL_CB_LOOP) | |
813 | debug_printf("%s: %s\n", str, SSL_state_string_long(s)); | |
814 | else if (where & SSL_CB_ALERT) | |
815 | debug_printf("SSL3 alert %s:%s:%s\n", | |
48224640 | 816 | str = where & SSL_CB_READ ? US"read" : US"write", |
0abc5a13 JH |
817 | SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret)); |
818 | else if (where & SSL_CB_EXIT) | |
819 | if (ret == 0) | |
820 | debug_printf("%s: failed in %s\n", str, SSL_state_string_long(s)); | |
821 | else if (ret < 0) | |
822 | debug_printf("%s: error in %s\n", str, SSL_state_string_long(s)); | |
823 | else if (where & SSL_CB_HANDSHAKE_START) | |
824 | debug_printf("%s: hshake start: %s\n", str, SSL_state_string_long(s)); | |
825 | else if (where & SSL_CB_HANDSHAKE_DONE) | |
826 | debug_printf("%s: hshake done: %s\n", str, SSL_state_string_long(s)); | |
827 | } | |
059ec3d9 PH |
828 | } |
829 | ||
8238bc7b | 830 | #ifdef OPENSSL_HAVE_KEYLOG_CB |
8a40db1c JH |
831 | static void |
832 | keylog_callback(const SSL *ssl, const char *line) | |
833 | { | |
834 | DEBUG(D_tls) debug_printf("%.200s\n", line); | |
835 | } | |
8238bc7b | 836 | #endif |
8a40db1c | 837 | |
059ec3d9 | 838 | |
b10c87b3 JH |
839 | #ifdef EXPERIMENTAL_TLS_RESUME |
840 | /* Manage the keysets used for encrypting the session tickets, on the server. */ | |
841 | ||
842 | typedef struct { /* Session ticket encryption key */ | |
843 | uschar name[16]; | |
844 | ||
845 | const EVP_CIPHER * aes_cipher; | |
4d93129f | 846 | uschar aes_key[32]; /* size needed depends on cipher. aes_128 implies 128/8 = 16? */ |
b10c87b3 JH |
847 | const EVP_MD * hmac_hash; |
848 | uschar hmac_key[16]; | |
849 | time_t renew; | |
850 | time_t expire; | |
851 | } exim_stek; | |
852 | ||
4d93129f JH |
853 | static exim_stek exim_tk; /* current key */ |
854 | static exim_stek exim_tk_old; /* previous key */ | |
b10c87b3 JH |
855 | |
856 | static void | |
857 | tk_init(void) | |
858 | { | |
4d93129f JH |
859 | time_t t = time(NULL); |
860 | ||
b10c87b3 JH |
861 | if (exim_tk.name[0]) |
862 | { | |
4d93129f | 863 | if (exim_tk.renew >= t) return; |
b10c87b3 JH |
864 | exim_tk_old = exim_tk; |
865 | } | |
866 | ||
867 | if (f.running_in_test_harness) ssl_session_timeout = 6; | |
868 | ||
869 | DEBUG(D_tls) debug_printf("OpenSSL: %s STEK\n", exim_tk.name[0] ? "rotating" : "creating"); | |
870 | if (RAND_bytes(exim_tk.aes_key, sizeof(exim_tk.aes_key)) <= 0) return; | |
871 | if (RAND_bytes(exim_tk.hmac_key, sizeof(exim_tk.hmac_key)) <= 0) return; | |
872 | if (RAND_bytes(exim_tk.name+1, sizeof(exim_tk.name)-1) <= 0) return; | |
873 | ||
874 | exim_tk.name[0] = 'E'; | |
4d93129f | 875 | exim_tk.aes_cipher = EVP_aes_256_cbc(); |
b10c87b3 | 876 | exim_tk.hmac_hash = EVP_sha256(); |
4d93129f JH |
877 | exim_tk.expire = t + ssl_session_timeout; |
878 | exim_tk.renew = t + ssl_session_timeout/2; | |
b10c87b3 JH |
879 | } |
880 | ||
881 | static exim_stek * | |
882 | tk_current(void) | |
883 | { | |
884 | if (!exim_tk.name[0]) return NULL; | |
885 | return &exim_tk; | |
886 | } | |
887 | ||
888 | static exim_stek * | |
889 | tk_find(const uschar * name) | |
890 | { | |
891 | return memcmp(name, exim_tk.name, sizeof(exim_tk.name)) == 0 ? &exim_tk | |
892 | : memcmp(name, exim_tk_old.name, sizeof(exim_tk_old.name)) == 0 ? &exim_tk_old | |
893 | : NULL; | |
894 | } | |
895 | ||
896 | /* Callback for session tickets, on server */ | |
897 | static int | |
898 | ticket_key_callback(SSL * ssl, uschar key_name[16], | |
899 | uschar * iv, EVP_CIPHER_CTX * ctx, HMAC_CTX * hctx, int enc) | |
900 | { | |
901 | tls_support * tlsp = server_static_cbinfo->tlsp; | |
902 | exim_stek * key; | |
903 | ||
904 | if (enc) | |
905 | { | |
906 | DEBUG(D_tls) debug_printf("ticket_key_callback: create new session\n"); | |
907 | tlsp->resumption |= RESUME_CLIENT_REQUESTED; | |
908 | ||
909 | if (RAND_bytes(iv, EVP_MAX_IV_LENGTH) <= 0) | |
910 | return -1; /* insufficient random */ | |
911 | ||
912 | if (!(key = tk_current())) /* current key doesn't exist or isn't valid */ | |
913 | return 0; /* key couldn't be created */ | |
914 | memcpy(key_name, key->name, 16); | |
d70fc283 | 915 | DEBUG(D_tls) debug_printf("STEK expire " TIME_T_FMT "\n", key->expire - time(NULL)); |
b10c87b3 JH |
916 | |
917 | /*XXX will want these dependent on the ssl session strength */ | |
918 | HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key), | |
919 | key->hmac_hash, NULL); | |
920 | EVP_EncryptInit_ex(ctx, key->aes_cipher, NULL, key->aes_key, iv); | |
921 | ||
922 | DEBUG(D_tls) debug_printf("ticket created\n"); | |
923 | return 1; | |
924 | } | |
925 | else | |
926 | { | |
927 | time_t now = time(NULL); | |
928 | ||
929 | DEBUG(D_tls) debug_printf("ticket_key_callback: retrieve session\n"); | |
930 | tlsp->resumption |= RESUME_CLIENT_SUGGESTED; | |
931 | ||
932 | if (!(key = tk_find(key_name)) || key->expire < now) | |
933 | { | |
934 | DEBUG(D_tls) | |
935 | { | |
936 | debug_printf("ticket not usable (%s)\n", key ? "expired" : "not found"); | |
d70fc283 | 937 | if (key) debug_printf("STEK expire " TIME_T_FMT "\n", key->expire - now); |
b10c87b3 JH |
938 | } |
939 | return 0; | |
940 | } | |
941 | ||
942 | HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key), | |
943 | key->hmac_hash, NULL); | |
944 | EVP_DecryptInit_ex(ctx, key->aes_cipher, NULL, key->aes_key, iv); | |
945 | ||
d70fc283 | 946 | DEBUG(D_tls) debug_printf("ticket usable, STEK expire " TIME_T_FMT "\n", key->expire - now); |
dea4b568 JH |
947 | |
948 | /* The ticket lifetime and renewal are the same as the STEK lifetime and | |
949 | renewal, which is overenthusiastic. A factor of, say, 3x longer STEK would | |
950 | be better. To do that we'd have to encode ticket lifetime in the name as | |
951 | we don't yet see the restored session. Could check posthandshake for TLS1.3 | |
952 | and trigger a new ticket then, but cannot do that for TLS1.2 */ | |
b10c87b3 JH |
953 | return key->renew < now ? 2 : 1; |
954 | } | |
955 | } | |
956 | #endif | |
957 | ||
958 | ||
059ec3d9 PH |
959 | |
960 | /************************************************* | |
961 | * Initialize for DH * | |
962 | *************************************************/ | |
963 | ||
964 | /* If dhparam is set, expand it, and load up the parameters for DH encryption. | |
965 | ||
966 | Arguments: | |
038597d2 | 967 | sctx The current SSL CTX (inbound or outbound) |
a799883d | 968 | dhparam DH parameter file or fixed parameter identity string |
7199e1ee | 969 | host connected host, if client; NULL if server |
cf0c6164 | 970 | errstr error string pointer |
059ec3d9 PH |
971 | |
972 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
973 | */ | |
974 | ||
975 | static BOOL | |
cf0c6164 | 976 | init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr) |
059ec3d9 | 977 | { |
059ec3d9 PH |
978 | BIO *bio; |
979 | DH *dh; | |
980 | uschar *dhexpanded; | |
a799883d | 981 | const char *pem; |
6600985a | 982 | int dh_bitsize; |
059ec3d9 | 983 | |
cf0c6164 | 984 | if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr)) |
059ec3d9 PH |
985 | return FALSE; |
986 | ||
0df4ab80 | 987 | if (!dhexpanded || !*dhexpanded) |
a799883d | 988 | bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1); |
a799883d | 989 | else if (dhexpanded[0] == '/') |
059ec3d9 | 990 | { |
0df4ab80 | 991 | if (!(bio = BIO_new_file(CS dhexpanded, "r"))) |
059ec3d9 | 992 | { |
7199e1ee | 993 | tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), |
cf0c6164 | 994 | host, US strerror(errno), errstr); |
a799883d | 995 | return FALSE; |
059ec3d9 | 996 | } |
a799883d PP |
997 | } |
998 | else | |
999 | { | |
1000 | if (Ustrcmp(dhexpanded, "none") == 0) | |
059ec3d9 | 1001 | { |
a799883d PP |
1002 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); |
1003 | return TRUE; | |
059ec3d9 | 1004 | } |
a799883d | 1005 | |
0df4ab80 | 1006 | if (!(pem = std_dh_prime_named(dhexpanded))) |
a799883d PP |
1007 | { |
1008 | tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), | |
cf0c6164 | 1009 | host, US strerror(errno), errstr); |
a799883d PP |
1010 | return FALSE; |
1011 | } | |
1012 | bio = BIO_new_mem_buf(CS pem, -1); | |
1013 | } | |
1014 | ||
0df4ab80 | 1015 | if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) |
a799883d | 1016 | { |
059ec3d9 | 1017 | BIO_free(bio); |
a799883d | 1018 | tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), |
cf0c6164 | 1019 | host, NULL, errstr); |
a799883d PP |
1020 | return FALSE; |
1021 | } | |
1022 | ||
6600985a PP |
1023 | /* note: our default limit of 2236 is not a multiple of 8; the limit comes from |
1024 | * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with | |
1025 | * 2236. But older OpenSSL can only report in bytes (octets), not bits. | |
1026 | * If someone wants to dance at the edge, then they can raise the limit or use | |
1027 | * current libraries. */ | |
1028 | #ifdef EXIM_HAVE_OPENSSL_DH_BITS | |
1029 | /* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022 | |
1030 | * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */ | |
1031 | dh_bitsize = DH_bits(dh); | |
1032 | #else | |
1033 | dh_bitsize = 8 * DH_size(dh); | |
1034 | #endif | |
1035 | ||
a799883d PP |
1036 | /* Even if it is larger, we silently return success rather than cause things |
1037 | * to fail out, so that a too-large DH will not knock out all TLS; it's a | |
1038 | * debatable choice. */ | |
6600985a | 1039 | if (dh_bitsize > tls_dh_max_bits) |
a799883d PP |
1040 | { |
1041 | DEBUG(D_tls) | |
170f4904 | 1042 | debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n", |
6600985a | 1043 | dh_bitsize, tls_dh_max_bits); |
a799883d PP |
1044 | } |
1045 | else | |
1046 | { | |
1047 | SSL_CTX_set_tmp_dh(sctx, dh); | |
1048 | DEBUG(D_tls) | |
1049 | debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", | |
6600985a | 1050 | dhexpanded ? dhexpanded : US"default", dh_bitsize); |
059ec3d9 PH |
1051 | } |
1052 | ||
a799883d PP |
1053 | DH_free(dh); |
1054 | BIO_free(bio); | |
1055 | ||
1056 | return TRUE; | |
059ec3d9 PH |
1057 | } |
1058 | ||
1059 | ||
1060 | ||
1061 | ||
038597d2 PP |
1062 | /************************************************* |
1063 | * Initialize for ECDH * | |
1064 | *************************************************/ | |
1065 | ||
1066 | /* Load parameters for ECDH encryption. | |
1067 | ||
1068 | For now, we stick to NIST P-256 because: it's simple and easy to configure; | |
1069 | it avoids any patent issues that might bite redistributors; despite events in | |
1070 | the news and concerns over curve choices, we're not cryptographers, we're not | |
1071 | pretending to be, and this is "good enough" to be better than no support, | |
1072 | protecting against most adversaries. Given another year or two, there might | |
1073 | be sufficient clarity about a "right" way forward to let us make an informed | |
1074 | decision, instead of a knee-jerk reaction. | |
1075 | ||
1076 | Longer-term, we should look at supporting both various named curves and | |
1077 | external files generated with "openssl ecparam", much as we do for init_dh(). | |
1078 | We should also support "none" as a value, to explicitly avoid initialisation. | |
1079 | ||
1080 | Patches welcome. | |
1081 | ||
1082 | Arguments: | |
1083 | sctx The current SSL CTX (inbound or outbound) | |
1084 | host connected host, if client; NULL if server | |
cf0c6164 | 1085 | errstr error string pointer |
038597d2 PP |
1086 | |
1087 | Returns: TRUE if OK (nothing to set up, or setup worked) | |
1088 | */ | |
1089 | ||
1090 | static BOOL | |
cf0c6164 | 1091 | init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr) |
038597d2 | 1092 | { |
63f0dbe0 JH |
1093 | #ifdef OPENSSL_NO_ECDH |
1094 | return TRUE; | |
1095 | #else | |
1096 | ||
10ca4f1c JH |
1097 | EC_KEY * ecdh; |
1098 | uschar * exp_curve; | |
1099 | int nid; | |
1100 | BOOL rv; | |
1101 | ||
038597d2 PP |
1102 | if (host) /* No ECDH setup for clients, only for servers */ |
1103 | return TRUE; | |
1104 | ||
10ca4f1c | 1105 | # ifndef EXIM_HAVE_ECDH |
038597d2 PP |
1106 | DEBUG(D_tls) |
1107 | debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); | |
1108 | return TRUE; | |
038597d2 | 1109 | # else |
10ca4f1c | 1110 | |
cf0c6164 | 1111 | if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr)) |
10ca4f1c JH |
1112 | return FALSE; |
1113 | if (!exp_curve || !*exp_curve) | |
1114 | return TRUE; | |
1115 | ||
8e53a4fc | 1116 | /* "auto" needs to be handled carefully. |
4c04137d | 1117 | * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1 |
8e53a4fc | 1118 | * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto |
4c04137d | 1119 | * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO) |
8e53a4fc HSHR |
1120 | * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection |
1121 | * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b | |
1122 | */ | |
10ca4f1c | 1123 | if (Ustrcmp(exp_curve, "auto") == 0) |
038597d2 | 1124 | { |
8e53a4fc | 1125 | #if OPENSSL_VERSION_NUMBER < 0x10002000L |
10ca4f1c | 1126 | DEBUG(D_tls) debug_printf( |
8e53a4fc | 1127 | "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n"); |
78a3bbd5 | 1128 | exp_curve = US"prime256v1"; |
8e53a4fc HSHR |
1129 | #else |
1130 | # if defined SSL_CTRL_SET_ECDH_AUTO | |
1131 | DEBUG(D_tls) debug_printf( | |
1132 | "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n"); | |
10ca4f1c JH |
1133 | SSL_CTX_set_ecdh_auto(sctx, 1); |
1134 | return TRUE; | |
8e53a4fc HSHR |
1135 | # else |
1136 | DEBUG(D_tls) debug_printf( | |
1137 | "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n"); | |
1138 | return TRUE; | |
1139 | # endif | |
1140 | #endif | |
10ca4f1c | 1141 | } |
038597d2 | 1142 | |
10ca4f1c JH |
1143 | DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve); |
1144 | if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef | |
1145 | # ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID | |
1146 | && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef | |
1147 | # endif | |
1148 | ) | |
1149 | { | |
cf0c6164 JH |
1150 | tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve), |
1151 | host, NULL, errstr); | |
10ca4f1c JH |
1152 | return FALSE; |
1153 | } | |
038597d2 | 1154 | |
10ca4f1c JH |
1155 | if (!(ecdh = EC_KEY_new_by_curve_name(nid))) |
1156 | { | |
cf0c6164 | 1157 | tls_error(US"Unable to create ec curve", host, NULL, errstr); |
10ca4f1c | 1158 | return FALSE; |
038597d2 | 1159 | } |
10ca4f1c JH |
1160 | |
1161 | /* The "tmp" in the name here refers to setting a temporary key | |
1162 | not to the stability of the interface. */ | |
1163 | ||
1164 | if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) | |
cf0c6164 | 1165 | tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr); |
10ca4f1c JH |
1166 | else |
1167 | DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); | |
1168 | ||
1169 | EC_KEY_free(ecdh); | |
1170 | return !rv; | |
1171 | ||
1172 | # endif /*EXIM_HAVE_ECDH*/ | |
1173 | #endif /*OPENSSL_NO_ECDH*/ | |
038597d2 PP |
1174 | } |
1175 | ||
1176 | ||
1177 | ||
1178 | ||
f2de3a33 | 1179 | #ifndef DISABLE_OCSP |
3f7eeb86 PP |
1180 | /************************************************* |
1181 | * Load OCSP information into state * | |
1182 | *************************************************/ | |
f5d78688 | 1183 | /* Called to load the server OCSP response from the given file into memory, once |
3f7eeb86 PP |
1184 | caller has determined this is needed. Checks validity. Debugs a message |
1185 | if invalid. | |
1186 | ||
1187 | ASSUMES: single response, for single cert. | |
1188 | ||
1189 | Arguments: | |
1190 | sctx the SSL_CTX* to update | |
1191 | cbinfo various parts of session state | |
1192 | expanded the filename putatively holding an OCSP response | |
1193 | ||
1194 | */ | |
1195 | ||
1196 | static void | |
f5d78688 | 1197 | ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) |
3f7eeb86 | 1198 | { |
ee5b1e28 JH |
1199 | BIO * bio; |
1200 | OCSP_RESPONSE * resp; | |
1201 | OCSP_BASICRESP * basic_response; | |
1202 | OCSP_SINGLERESP * single_response; | |
1203 | ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd; | |
ee5b1e28 | 1204 | STACK_OF(X509) * sk; |
3f7eeb86 PP |
1205 | unsigned long verify_flags; |
1206 | int status, reason, i; | |
1207 | ||
f5d78688 JH |
1208 | cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); |
1209 | if (cbinfo->u_ocsp.server.response) | |
3f7eeb86 | 1210 | { |
f5d78688 JH |
1211 | OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); |
1212 | cbinfo->u_ocsp.server.response = NULL; | |
3f7eeb86 PP |
1213 | } |
1214 | ||
ee5b1e28 | 1215 | if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"))) |
3f7eeb86 PP |
1216 | { |
1217 | DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", | |
f5d78688 | 1218 | cbinfo->u_ocsp.server.file_expanded); |
3f7eeb86 PP |
1219 | return; |
1220 | } | |
1221 | ||
1222 | resp = d2i_OCSP_RESPONSE_bio(bio, NULL); | |
1223 | BIO_free(bio); | |
1224 | if (!resp) | |
1225 | { | |
1226 | DEBUG(D_tls) debug_printf("Error reading OCSP response.\n"); | |
1227 | return; | |
1228 | } | |
1229 | ||
ee5b1e28 | 1230 | if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL) |
3f7eeb86 PP |
1231 | { |
1232 | DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n", | |
1233 | OCSP_response_status_str(status), status); | |
f5d78688 | 1234 | goto bad; |
3f7eeb86 PP |
1235 | } |
1236 | ||
ee5b1e28 | 1237 | if (!(basic_response = OCSP_response_get1_basic(resp))) |
3f7eeb86 PP |
1238 | { |
1239 | DEBUG(D_tls) | |
1240 | debug_printf("OCSP response parse error: unable to extract basic response.\n"); | |
f5d78688 | 1241 | goto bad; |
3f7eeb86 PP |
1242 | } |
1243 | ||
c3033f13 | 1244 | sk = cbinfo->verify_stack; |
3f7eeb86 PP |
1245 | verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */ |
1246 | ||
1247 | /* May need to expose ability to adjust those flags? | |
1248 | OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT | |
1249 | OCSP_TRUSTOTHER OCSP_NOINTERN */ | |
1250 | ||
4c04137d | 1251 | /* This does a full verify on the OCSP proof before we load it for serving |
ee5b1e28 JH |
1252 | up; possibly overkill - just date-checks might be nice enough. |
1253 | ||
1254 | OCSP_basic_verify takes a "store" arg, but does not | |
1255 | use it for the chain verification, which is all we do | |
1256 | when OCSP_NOVERIFY is set. The content from the wire | |
1257 | "basic_response" and a cert-stack "sk" are all that is used. | |
1258 | ||
c3033f13 JH |
1259 | We have a stack, loaded in setup_certs() if tls_verify_certificates |
1260 | was a file (not a directory, or "system"). It is unfortunate we | |
1261 | cannot used the connection context store, as that would neatly | |
1262 | handle the "system" case too, but there seems to be no library | |
1263 | function for getting a stack from a store. | |
e3555426 | 1264 | [ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ] |
c3033f13 JH |
1265 | We do not free the stack since it could be needed a second time for |
1266 | SNI handling. | |
1267 | ||
4c04137d | 1268 | Separately we might try to replace using OCSP_basic_verify() - which seems to not |
5ec37a55 | 1269 | be a public interface into the OpenSSL library (there's no manual entry) - |
ee5b1e28 | 1270 | But what with? We also use OCSP_basic_verify in the client stapling callback. |
4c04137d | 1271 | And there we NEED it; we must verify that status... unless the |
ee5b1e28 JH |
1272 | library does it for us anyway? */ |
1273 | ||
1274 | if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0) | |
3f7eeb86 | 1275 | { |
ee5b1e28 JH |
1276 | DEBUG(D_tls) |
1277 | { | |
0abc5a13 | 1278 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3f7eeb86 | 1279 | debug_printf("OCSP response verify failure: %s\n", US ssl_errstring); |
f5d78688 JH |
1280 | } |
1281 | goto bad; | |
3f7eeb86 PP |
1282 | } |
1283 | ||
1284 | /* Here's the simplifying assumption: there's only one response, for the | |
1285 | one certificate we use, and nothing for anything else in a chain. If this | |
1286 | proves false, we need to extract a cert id from our issued cert | |
1287 | (tls_certificate) and use that for OCSP_resp_find_status() (which finds the | |
1288 | right cert in the stack and then calls OCSP_single_get0_status()). | |
1289 | ||
1290 | I'm hoping to avoid reworking a bunch more of how we handle state here. */ | |
ee5b1e28 JH |
1291 | |
1292 | if (!(single_response = OCSP_resp_get0(basic_response, 0))) | |
3f7eeb86 PP |
1293 | { |
1294 | DEBUG(D_tls) | |
1295 | debug_printf("Unable to get first response from OCSP basic response.\n"); | |
f5d78688 | 1296 | goto bad; |
3f7eeb86 PP |
1297 | } |
1298 | ||
1299 | status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd); | |
f5d78688 | 1300 | if (status != V_OCSP_CERTSTATUS_GOOD) |
3f7eeb86 | 1301 | { |
f5d78688 JH |
1302 | DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n", |
1303 | OCSP_cert_status_str(status), status, | |
1304 | OCSP_crl_reason_str(reason), reason); | |
1305 | goto bad; | |
3f7eeb86 PP |
1306 | } |
1307 | ||
1308 | if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
1309 | { | |
1310 | DEBUG(D_tls) debug_printf("OCSP status invalid times.\n"); | |
f5d78688 | 1311 | goto bad; |
3f7eeb86 PP |
1312 | } |
1313 | ||
f5d78688 | 1314 | supply_response: |
e5489333 JH |
1315 | /*XXX stack? (these tag points are for multiple leaf-cert support for ocsp */ |
1316 | cbinfo->u_ocsp.server.response = resp; | |
f5d78688 JH |
1317 | return; |
1318 | ||
1319 | bad: | |
8768d548 | 1320 | if (f.running_in_test_harness) |
018058b2 JH |
1321 | { |
1322 | extern char ** environ; | |
d7978c0f | 1323 | if (environ) for (uschar ** p = USS environ; *p; p++) |
018058b2 JH |
1324 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) |
1325 | { | |
1326 | DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n"); | |
1327 | goto supply_response; | |
1328 | } | |
1329 | } | |
f5d78688 | 1330 | return; |
3f7eeb86 | 1331 | } |
f2de3a33 | 1332 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1333 | |
1334 | ||
1335 | ||
1336 | ||
23bb6982 JH |
1337 | /* Create and install a selfsigned certificate, for use in server mode */ |
1338 | ||
1339 | static int | |
cf0c6164 | 1340 | tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr) |
23bb6982 JH |
1341 | { |
1342 | X509 * x509 = NULL; | |
1343 | EVP_PKEY * pkey; | |
1344 | RSA * rsa; | |
1345 | X509_NAME * name; | |
1346 | uschar * where; | |
1347 | ||
1348 | where = US"allocating pkey"; | |
1349 | if (!(pkey = EVP_PKEY_new())) | |
1350 | goto err; | |
1351 | ||
1352 | where = US"allocating cert"; | |
1353 | if (!(x509 = X509_new())) | |
1354 | goto err; | |
1355 | ||
1356 | where = US"generating pkey"; | |
6aac3239 | 1357 | if (!(rsa = rsa_callback(NULL, 0, 2048))) |
23bb6982 JH |
1358 | goto err; |
1359 | ||
4c04137d | 1360 | where = US"assigning pkey"; |
23bb6982 JH |
1361 | if (!EVP_PKEY_assign_RSA(pkey, rsa)) |
1362 | goto err; | |
1363 | ||
1364 | X509_set_version(x509, 2); /* N+1 - version 3 */ | |
1613fd68 | 1365 | ASN1_INTEGER_set(X509_get_serialNumber(x509), 1); |
23bb6982 JH |
1366 | X509_gmtime_adj(X509_get_notBefore(x509), 0); |
1367 | X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60); /* 1 hour */ | |
1368 | X509_set_pubkey(x509, pkey); | |
1369 | ||
1370 | name = X509_get_subject_name(x509); | |
1371 | X509_NAME_add_entry_by_txt(name, "C", | |
4dc2379a | 1372 | MBSTRING_ASC, CUS "UK", -1, -1, 0); |
23bb6982 | 1373 | X509_NAME_add_entry_by_txt(name, "O", |
4dc2379a | 1374 | MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0); |
23bb6982 | 1375 | X509_NAME_add_entry_by_txt(name, "CN", |
4dc2379a | 1376 | MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0); |
23bb6982 JH |
1377 | X509_set_issuer_name(x509, name); |
1378 | ||
1379 | where = US"signing cert"; | |
1380 | if (!X509_sign(x509, pkey, EVP_md5())) | |
1381 | goto err; | |
1382 | ||
1383 | where = US"installing selfsign cert"; | |
1384 | if (!SSL_CTX_use_certificate(sctx, x509)) | |
1385 | goto err; | |
1386 | ||
1387 | where = US"installing selfsign key"; | |
1388 | if (!SSL_CTX_use_PrivateKey(sctx, pkey)) | |
1389 | goto err; | |
1390 | ||
1391 | return OK; | |
1392 | ||
1393 | err: | |
cf0c6164 | 1394 | (void) tls_error(where, NULL, NULL, errstr); |
23bb6982 JH |
1395 | if (x509) X509_free(x509); |
1396 | if (pkey) EVP_PKEY_free(pkey); | |
1397 | return DEFER; | |
1398 | } | |
1399 | ||
1400 | ||
1401 | ||
1402 | ||
ba86e143 JH |
1403 | static int |
1404 | tls_add_certfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1405 | uschar ** errstr) | |
1406 | { | |
1407 | DEBUG(D_tls) debug_printf("tls_certificate file %s\n", file); | |
1408 | if (!SSL_CTX_use_certificate_chain_file(sctx, CS file)) | |
1409 | return tls_error(string_sprintf( | |
1410 | "SSL_CTX_use_certificate_chain_file file=%s", file), | |
1411 | cbinfo->host, NULL, errstr); | |
1412 | return 0; | |
1413 | } | |
1414 | ||
1415 | static int | |
1416 | tls_add_pkeyfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, | |
1417 | uschar ** errstr) | |
1418 | { | |
1419 | DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", file); | |
1420 | if (!SSL_CTX_use_PrivateKey_file(sctx, CS file, SSL_FILETYPE_PEM)) | |
1421 | return tls_error(string_sprintf( | |
1422 | "SSL_CTX_use_PrivateKey_file file=%s", file), cbinfo->host, NULL, errstr); | |
1423 | return 0; | |
1424 | } | |
1425 | ||
1426 | ||
7be682ca PP |
1427 | /************************************************* |
1428 | * Expand key and cert file specs * | |
1429 | *************************************************/ | |
1430 | ||
f5d78688 | 1431 | /* Called once during tls_init and possibly again during TLS setup, for a |
7be682ca PP |
1432 | new context, if Server Name Indication was used and tls_sni was seen in |
1433 | the certificate string. | |
1434 | ||
1435 | Arguments: | |
1436 | sctx the SSL_CTX* to update | |
1437 | cbinfo various parts of session state | |
cf0c6164 | 1438 | errstr error string pointer |
7be682ca PP |
1439 | |
1440 | Returns: OK/DEFER/FAIL | |
1441 | */ | |
1442 | ||
1443 | static int | |
cf0c6164 JH |
1444 | tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, |
1445 | uschar ** errstr) | |
7be682ca PP |
1446 | { |
1447 | uschar *expanded; | |
1448 | ||
23bb6982 | 1449 | if (!cbinfo->certificate) |
7be682ca | 1450 | { |
ba86e143 | 1451 | if (!cbinfo->is_server) /* client */ |
23bb6982 | 1452 | return OK; |
afdb5e9c | 1453 | /* server */ |
cf0c6164 | 1454 | if (tls_install_selfsign(sctx, errstr) != OK) |
23bb6982 | 1455 | return DEFER; |
7be682ca | 1456 | } |
23bb6982 JH |
1457 | else |
1458 | { | |
ba86e143 JH |
1459 | int err; |
1460 | ||
23bb6982 JH |
1461 | if (Ustrstr(cbinfo->certificate, US"tls_sni") || |
1462 | Ustrstr(cbinfo->certificate, US"tls_in_sni") || | |
1463 | Ustrstr(cbinfo->certificate, US"tls_out_sni") | |
1464 | ) | |
1465 | reexpand_tls_files_for_sni = TRUE; | |
7be682ca | 1466 | |
cf0c6164 | 1467 | if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr)) |
23bb6982 JH |
1468 | return DEFER; |
1469 | ||
ba86e143 JH |
1470 | if (expanded) |
1471 | if (cbinfo->is_server) | |
1472 | { | |
1473 | const uschar * file_list = expanded; | |
1474 | int sep = 0; | |
1475 | uschar * file; | |
1476 | ||
1477 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1478 | if ((err = tls_add_certfile(sctx, cbinfo, file, errstr))) | |
1479 | return err; | |
1480 | } | |
1481 | else /* would there ever be a need for multiple client certs? */ | |
1482 | if ((err = tls_add_certfile(sctx, cbinfo, expanded, errstr))) | |
1483 | return err; | |
7be682ca | 1484 | |
5a2a0989 JH |
1485 | if ( cbinfo->privatekey |
1486 | && !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr)) | |
23bb6982 | 1487 | return DEFER; |
7be682ca | 1488 | |
23bb6982 JH |
1489 | /* If expansion was forced to fail, key_expanded will be NULL. If the result |
1490 | of the expansion is an empty string, ignore it also, and assume the private | |
1491 | key is in the same file as the certificate. */ | |
1492 | ||
1493 | if (expanded && *expanded) | |
ba86e143 JH |
1494 | if (cbinfo->is_server) |
1495 | { | |
1496 | const uschar * file_list = expanded; | |
1497 | int sep = 0; | |
1498 | uschar * file; | |
1499 | ||
1500 | while (file = string_nextinlist(&file_list, &sep, NULL, 0)) | |
1501 | if ((err = tls_add_pkeyfile(sctx, cbinfo, file, errstr))) | |
1502 | return err; | |
1503 | } | |
1504 | else /* would there ever be a need for multiple client certs? */ | |
1505 | if ((err = tls_add_pkeyfile(sctx, cbinfo, expanded, errstr))) | |
1506 | return err; | |
7be682ca PP |
1507 | } |
1508 | ||
f2de3a33 | 1509 | #ifndef DISABLE_OCSP |
f40d5be3 | 1510 | if (cbinfo->is_server && cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1511 | { |
47195144 | 1512 | /*XXX stack*/ |
cf0c6164 | 1513 | if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr)) |
3f7eeb86 PP |
1514 | return DEFER; |
1515 | ||
f40d5be3 | 1516 | if (expanded && *expanded) |
3f7eeb86 PP |
1517 | { |
1518 | DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); | |
f40d5be3 JH |
1519 | if ( cbinfo->u_ocsp.server.file_expanded |
1520 | && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) | |
3f7eeb86 | 1521 | { |
f40d5be3 JH |
1522 | DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n"); |
1523 | } | |
1524 | else | |
f40d5be3 | 1525 | ocsp_load_response(sctx, cbinfo, expanded); |
3f7eeb86 PP |
1526 | } |
1527 | } | |
1528 | #endif | |
1529 | ||
7be682ca PP |
1530 | return OK; |
1531 | } | |
1532 | ||
1533 | ||
1534 | ||
1535 | ||
1536 | /************************************************* | |
1537 | * Callback to handle SNI * | |
1538 | *************************************************/ | |
1539 | ||
1540 | /* Called when acting as server during the TLS session setup if a Server Name | |
1541 | Indication extension was sent by the client. | |
1542 | ||
1543 | API documentation is OpenSSL s_server.c implementation. | |
1544 | ||
1545 | Arguments: | |
1546 | s SSL* of the current session | |
1547 | ad unknown (part of OpenSSL API) (unused) | |
1548 | arg Callback of "our" registered data | |
1549 | ||
1550 | Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} | |
b10c87b3 JH |
1551 | |
1552 | XXX might need to change to using ClientHello callback, | |
1553 | per https://www.openssl.org/docs/manmaster/man3/SSL_client_hello_cb_fn.html | |
7be682ca PP |
1554 | */ |
1555 | ||
3bcbbbe2 | 1556 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
7be682ca PP |
1557 | static int |
1558 | tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) | |
1559 | { | |
1560 | const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); | |
3f7eeb86 | 1561 | tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; |
7be682ca | 1562 | int rc; |
3f0945ff | 1563 | int old_pool = store_pool; |
cf0c6164 | 1564 | uschar * dummy_errstr; |
7be682ca PP |
1565 | |
1566 | if (!servername) | |
1567 | return SSL_TLSEXT_ERR_OK; | |
1568 | ||
3f0945ff | 1569 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", servername, |
7be682ca PP |
1570 | reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); |
1571 | ||
1572 | /* Make the extension value available for expansion */ | |
3f0945ff | 1573 | store_pool = POOL_PERM; |
89a80675 | 1574 | tls_in.sni = string_copy_taint(US servername, TRUE); |
3f0945ff | 1575 | store_pool = old_pool; |
7be682ca PP |
1576 | |
1577 | if (!reexpand_tls_files_for_sni) | |
1578 | return SSL_TLSEXT_ERR_OK; | |
1579 | ||
1580 | /* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; | |
1581 | not confident that memcpy wouldn't break some internal reference counting. | |
1582 | Especially since there's a references struct member, which would be off. */ | |
1583 | ||
7a8b9519 JH |
1584 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1585 | if (!(server_sni = SSL_CTX_new(TLS_server_method()))) | |
1586 | #else | |
0df4ab80 | 1587 | if (!(server_sni = SSL_CTX_new(SSLv23_server_method()))) |
7a8b9519 | 1588 | #endif |
7be682ca | 1589 | { |
0abc5a13 | 1590 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
7be682ca | 1591 | DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); |
5a2a0989 | 1592 | goto bad; |
7be682ca PP |
1593 | } |
1594 | ||
1595 | /* Not sure how many of these are actually needed, since SSL object | |
1596 | already exists. Might even need this selfsame callback, for reneg? */ | |
1597 | ||
817d9f57 JH |
1598 | SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx)); |
1599 | SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx)); | |
1600 | SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx)); | |
1601 | SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx)); | |
1602 | SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb); | |
1603 | SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo); | |
038597d2 | 1604 | |
cf0c6164 JH |
1605 | if ( !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr) |
1606 | || !init_ecdh(server_sni, NULL, &dummy_errstr) | |
038597d2 | 1607 | ) |
5a2a0989 | 1608 | goto bad; |
038597d2 | 1609 | |
ca954d7f JH |
1610 | if ( cbinfo->server_cipher_list |
1611 | && !SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list)) | |
5a2a0989 | 1612 | goto bad; |
ca954d7f | 1613 | |
f2de3a33 | 1614 | #ifndef DISABLE_OCSP |
f5d78688 | 1615 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 1616 | { |
f5d78688 | 1617 | SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb); |
14c7b357 | 1618 | SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo); |
3f7eeb86 PP |
1619 | } |
1620 | #endif | |
7be682ca | 1621 | |
c3033f13 | 1622 | if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE, |
cf0c6164 | 1623 | verify_callback_server, &dummy_errstr)) != OK) |
5a2a0989 | 1624 | goto bad; |
7be682ca | 1625 | |
3f7eeb86 PP |
1626 | /* do this after setup_certs, because this can require the certs for verifying |
1627 | OCSP information. */ | |
cf0c6164 | 1628 | if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK) |
5a2a0989 | 1629 | goto bad; |
a799883d | 1630 | |
7be682ca | 1631 | DEBUG(D_tls) debug_printf("Switching SSL context.\n"); |
817d9f57 | 1632 | SSL_set_SSL_CTX(s, server_sni); |
7be682ca | 1633 | return SSL_TLSEXT_ERR_OK; |
5a2a0989 JH |
1634 | |
1635 | bad: return SSL_TLSEXT_ERR_ALERT_FATAL; | |
7be682ca | 1636 | } |
3bcbbbe2 | 1637 | #endif /* EXIM_HAVE_OPENSSL_TLSEXT */ |
7be682ca PP |
1638 | |
1639 | ||
1640 | ||
1641 | ||
f2de3a33 | 1642 | #ifndef DISABLE_OCSP |
f5d78688 | 1643 | |
3f7eeb86 PP |
1644 | /************************************************* |
1645 | * Callback to handle OCSP Stapling * | |
1646 | *************************************************/ | |
1647 | ||
1648 | /* Called when acting as server during the TLS session setup if the client | |
1649 | requests OCSP information with a Certificate Status Request. | |
1650 | ||
1651 | Documentation via openssl s_server.c and the Apache patch from the OpenSSL | |
1652 | project. | |
1653 | ||
1654 | */ | |
1655 | ||
1656 | static int | |
f5d78688 | 1657 | tls_server_stapling_cb(SSL *s, void *arg) |
3f7eeb86 PP |
1658 | { |
1659 | const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; | |
47195144 | 1660 | uschar *response_der; /*XXX blob */ |
3f7eeb86 PP |
1661 | int response_der_len; |
1662 | ||
47195144 JH |
1663 | /*XXX stack: use SSL_get_certificate() to see which cert; from that work |
1664 | out which ocsp blob to send. Unfortunately, SSL_get_certificate is known | |
1665 | buggy in current OpenSSL; it returns the last cert loaded always rather than | |
1666 | the one actually presented. So we can't support a stack of OCSP proofs at | |
1667 | this time. */ | |
1668 | ||
af4a1bca | 1669 | DEBUG(D_tls) |
b3ef41c9 | 1670 | debug_printf("Received TLS status request (OCSP stapling); %s response\n", |
f5d78688 JH |
1671 | cbinfo->u_ocsp.server.response ? "have" : "lack"); |
1672 | ||
44662487 | 1673 | tls_in.ocsp = OCSP_NOT_RESP; |
f5d78688 | 1674 | if (!cbinfo->u_ocsp.server.response) |
3f7eeb86 PP |
1675 | return SSL_TLSEXT_ERR_NOACK; |
1676 | ||
1677 | response_der = NULL; | |
47195144 | 1678 | response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, /*XXX stack*/ |
44662487 | 1679 | &response_der); |
3f7eeb86 PP |
1680 | if (response_der_len <= 0) |
1681 | return SSL_TLSEXT_ERR_NOACK; | |
1682 | ||
5e55c7a9 | 1683 | SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len); |
44662487 | 1684 | tls_in.ocsp = OCSP_VFIED; |
3f7eeb86 PP |
1685 | return SSL_TLSEXT_ERR_OK; |
1686 | } | |
1687 | ||
3f7eeb86 | 1688 | |
f5d78688 JH |
1689 | static void |
1690 | time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time) | |
1691 | { | |
1692 | BIO_printf(bp, "\t%s: ", str); | |
1693 | ASN1_GENERALIZEDTIME_print(bp, time); | |
1694 | BIO_puts(bp, "\n"); | |
1695 | } | |
1696 | ||
1697 | static int | |
1698 | tls_client_stapling_cb(SSL *s, void *arg) | |
1699 | { | |
1700 | tls_ext_ctx_cb * cbinfo = arg; | |
1701 | const unsigned char * p; | |
1702 | int len; | |
1703 | OCSP_RESPONSE * rsp; | |
1704 | OCSP_BASICRESP * bs; | |
1705 | int i; | |
1706 | ||
1707 | DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):"); | |
1708 | len = SSL_get_tlsext_status_ocsp_resp(s, &p); | |
1709 | if(!p) | |
1710 | { | |
44662487 | 1711 | /* Expect this when we requested ocsp but got none */ |
6c6d6e48 | 1712 | if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher)) |
44662487 | 1713 | log_write(0, LOG_MAIN, "Received TLS status callback, null content"); |
f5d78688 JH |
1714 | else |
1715 | DEBUG(D_tls) debug_printf(" null\n"); | |
44662487 | 1716 | return cbinfo->u_ocsp.client.verify_required ? 0 : 1; |
f5d78688 | 1717 | } |
018058b2 | 1718 | |
c82de233 JH |
1719 | if (!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) |
1720 | { | |
1721 | tls_out.ocsp = OCSP_FAILED; /*XXX should use tlsp-> to permit concurrent outbound */ | |
6c6d6e48 | 1722 | if (LOGGING(tls_cipher)) |
1eca31ca | 1723 | log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); |
f5d78688 JH |
1724 | else |
1725 | DEBUG(D_tls) debug_printf(" parse error\n"); | |
1726 | return 0; | |
c82de233 | 1727 | } |
f5d78688 | 1728 | |
c82de233 | 1729 | if (!(bs = OCSP_response_get1_basic(rsp))) |
f5d78688 | 1730 | { |
018058b2 | 1731 | tls_out.ocsp = OCSP_FAILED; |
6c6d6e48 | 1732 | if (LOGGING(tls_cipher)) |
1eca31ca | 1733 | log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); |
f5d78688 JH |
1734 | else |
1735 | DEBUG(D_tls) debug_printf(" error parsing response\n"); | |
1736 | OCSP_RESPONSE_free(rsp); | |
1737 | return 0; | |
1738 | } | |
1739 | ||
1740 | /* We'd check the nonce here if we'd put one in the request. */ | |
1741 | /* However that would defeat cacheability on the server so we don't. */ | |
1742 | ||
f5d78688 JH |
1743 | /* This section of code reworked from OpenSSL apps source; |
1744 | The OpenSSL Project retains copyright: | |
1745 | Copyright (c) 1999 The OpenSSL Project. All rights reserved. | |
1746 | */ | |
1747 | { | |
1748 | BIO * bp = NULL; | |
f5d78688 JH |
1749 | int status, reason; |
1750 | ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd; | |
1751 | ||
57887ecc | 1752 | DEBUG(D_tls) bp = BIO_new_fp(debug_file, BIO_NOCLOSE); |
f5d78688 JH |
1753 | |
1754 | /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */ | |
1755 | ||
1756 | /* Use the chain that verified the server cert to verify the stapled info */ | |
1757 | /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */ | |
1758 | ||
c3033f13 | 1759 | if ((i = OCSP_basic_verify(bs, cbinfo->verify_stack, |
44662487 | 1760 | cbinfo->u_ocsp.client.verify_store, 0)) <= 0) |
f5d78688 | 1761 | { |
018058b2 | 1762 | tls_out.ocsp = OCSP_FAILED; |
57887ecc JH |
1763 | if (LOGGING(tls_cipher)) log_write(0, LOG_MAIN, |
1764 | "Received TLS cert status response, itself unverifiable: %s", | |
1765 | ERR_reason_error_string(ERR_peek_error())); | |
f5d78688 JH |
1766 | BIO_printf(bp, "OCSP response verify failure\n"); |
1767 | ERR_print_errors(bp); | |
57887ecc | 1768 | OCSP_RESPONSE_print(bp, rsp, 0); |
c8dfb21d | 1769 | goto failed; |
f5d78688 JH |
1770 | } |
1771 | ||
1772 | BIO_printf(bp, "OCSP response well-formed and signed OK\n"); | |
1773 | ||
c8dfb21d JH |
1774 | /*XXX So we have a good stapled OCSP status. How do we know |
1775 | it is for the cert of interest? OpenSSL 1.1.0 has a routine | |
1776 | OCSP_resp_find_status() which matches on a cert id, which presumably | |
1777 | we should use. Making an id needs OCSP_cert_id_new(), which takes | |
1778 | issuerName, issuerKey, serialNumber. Are they all in the cert? | |
1779 | ||
1780 | For now, carry on blindly accepting the resp. */ | |
1781 | ||
f5d78688 | 1782 | { |
f5d78688 JH |
1783 | OCSP_SINGLERESP * single; |
1784 | ||
c8dfb21d JH |
1785 | #ifdef EXIM_HAVE_OCSP_RESP_COUNT |
1786 | if (OCSP_resp_count(bs) != 1) | |
1787 | #else | |
1788 | STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses; | |
f5d78688 | 1789 | if (sk_OCSP_SINGLERESP_num(sresp) != 1) |
c8dfb21d | 1790 | #endif |
f5d78688 | 1791 | { |
018058b2 | 1792 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1793 | log_write(0, LOG_MAIN, "OCSP stapling " |
1794 | "with multiple responses not handled"); | |
c8dfb21d | 1795 | goto failed; |
f5d78688 JH |
1796 | } |
1797 | single = OCSP_resp_get0(bs, 0); | |
44662487 JH |
1798 | status = OCSP_single_get0_status(single, &reason, &rev, |
1799 | &thisupd, &nextupd); | |
f5d78688 JH |
1800 | } |
1801 | ||
f5d78688 JH |
1802 | DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd); |
1803 | DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd); | |
44662487 JH |
1804 | if (!OCSP_check_validity(thisupd, nextupd, |
1805 | EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE)) | |
f5d78688 | 1806 | { |
018058b2 | 1807 | tls_out.ocsp = OCSP_FAILED; |
f5d78688 JH |
1808 | DEBUG(D_tls) ERR_print_errors(bp); |
1809 | log_write(0, LOG_MAIN, "Server OSCP dates invalid"); | |
f5d78688 | 1810 | } |
44662487 | 1811 | else |
f5d78688 | 1812 | { |
44662487 JH |
1813 | DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n", |
1814 | OCSP_cert_status_str(status)); | |
1815 | switch(status) | |
1816 | { | |
1817 | case V_OCSP_CERTSTATUS_GOOD: | |
44662487 | 1818 | tls_out.ocsp = OCSP_VFIED; |
018058b2 | 1819 | i = 1; |
c8dfb21d | 1820 | goto good; |
44662487 | 1821 | case V_OCSP_CERTSTATUS_REVOKED: |
018058b2 | 1822 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1823 | log_write(0, LOG_MAIN, "Server certificate revoked%s%s", |
1824 | reason != -1 ? "; reason: " : "", | |
1825 | reason != -1 ? OCSP_crl_reason_str(reason) : ""); | |
1826 | DEBUG(D_tls) time_print(bp, "Revocation Time", rev); | |
44662487 JH |
1827 | break; |
1828 | default: | |
018058b2 | 1829 | tls_out.ocsp = OCSP_FAILED; |
44662487 JH |
1830 | log_write(0, LOG_MAIN, |
1831 | "Server certificate status unknown, in OCSP stapling"); | |
44662487 JH |
1832 | break; |
1833 | } | |
f5d78688 | 1834 | } |
c8dfb21d JH |
1835 | failed: |
1836 | i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; | |
1837 | good: | |
f5d78688 JH |
1838 | BIO_free(bp); |
1839 | } | |
1840 | ||
1841 | OCSP_RESPONSE_free(rsp); | |
1842 | return i; | |
1843 | } | |
f2de3a33 | 1844 | #endif /*!DISABLE_OCSP*/ |
3f7eeb86 PP |
1845 | |
1846 | ||
059ec3d9 PH |
1847 | /************************************************* |
1848 | * Initialize for TLS * | |
1849 | *************************************************/ | |
1850 | ||
e51c7be2 JH |
1851 | /* Called from both server and client code, to do preliminary initialization |
1852 | of the library. We allocate and return a context structure. | |
059ec3d9 PH |
1853 | |
1854 | Arguments: | |
946ecbe0 | 1855 | ctxp returned SSL context |
059ec3d9 PH |
1856 | host connected host, if client; NULL if server |
1857 | dhparam DH parameter file | |
1858 | certificate certificate file | |
1859 | privatekey private key | |
f5d78688 | 1860 | ocsp_file file of stapling info (server); flag for require ocsp (client) |
059ec3d9 | 1861 | addr address if client; NULL if server (for some randomness) |
946ecbe0 | 1862 | cbp place to put allocated callback context |
cf0c6164 | 1863 | errstr error string pointer |
059ec3d9 PH |
1864 | |
1865 | Returns: OK/DEFER/FAIL | |
1866 | */ | |
1867 | ||
1868 | static int | |
817d9f57 | 1869 | tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, |
3f7eeb86 | 1870 | uschar *privatekey, |
f2de3a33 | 1871 | #ifndef DISABLE_OCSP |
47195144 | 1872 | uschar *ocsp_file, /*XXX stack, in server*/ |
3f7eeb86 | 1873 | #endif |
b10c87b3 JH |
1874 | address_item *addr, tls_ext_ctx_cb ** cbp, |
1875 | tls_support * tlsp, | |
1876 | uschar ** errstr) | |
059ec3d9 | 1877 | { |
7006ee24 | 1878 | SSL_CTX * ctx; |
77bb000f | 1879 | long init_options; |
7be682ca | 1880 | int rc; |
a7538db1 | 1881 | tls_ext_ctx_cb * cbinfo; |
7be682ca PP |
1882 | |
1883 | cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); | |
b10c87b3 | 1884 | cbinfo->tlsp = tlsp; |
7be682ca PP |
1885 | cbinfo->certificate = certificate; |
1886 | cbinfo->privatekey = privatekey; | |
a6510420 | 1887 | cbinfo->is_server = host==NULL; |
f2de3a33 | 1888 | #ifndef DISABLE_OCSP |
c3033f13 | 1889 | cbinfo->verify_stack = NULL; |
a6510420 | 1890 | if (!host) |
f5d78688 JH |
1891 | { |
1892 | cbinfo->u_ocsp.server.file = ocsp_file; | |
1893 | cbinfo->u_ocsp.server.file_expanded = NULL; | |
1894 | cbinfo->u_ocsp.server.response = NULL; | |
1895 | } | |
1896 | else | |
1897 | cbinfo->u_ocsp.client.verify_store = NULL; | |
3f7eeb86 | 1898 | #endif |
7be682ca | 1899 | cbinfo->dhparam = dhparam; |
0df4ab80 | 1900 | cbinfo->server_cipher_list = NULL; |
7be682ca | 1901 | cbinfo->host = host; |
0cbf2b82 | 1902 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1903 | cbinfo->event_action = NULL; |
1904 | #endif | |
77bb000f | 1905 | |
7434882d | 1906 | #ifdef EXIM_NEED_OPENSSL_INIT |
059ec3d9 PH |
1907 | SSL_load_error_strings(); /* basic set up */ |
1908 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 1909 | #endif |
059ec3d9 | 1910 | |
c8dfb21d | 1911 | #ifdef EXIM_HAVE_SHA256 |
77bb000f | 1912 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the |
a0475b69 TK |
1913 | list of available digests. */ |
1914 | EVP_add_digest(EVP_sha256()); | |
cf1ef1a9 | 1915 | #endif |
a0475b69 | 1916 | |
f0f5a555 PP |
1917 | /* Create a context. |
1918 | The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant | |
1919 | negotiation in the different methods; as far as I can tell, the only | |
1920 | *_{server,client}_method which allows negotiation is SSLv23, which exists even | |
1921 | when OpenSSL is built without SSLv2 support. | |
1922 | By disabling with openssl_options, we can let admins re-enable with the | |
1923 | existing knob. */ | |
059ec3d9 | 1924 | |
7a8b9519 JH |
1925 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
1926 | if (!(ctx = SSL_CTX_new(host ? TLS_client_method() : TLS_server_method()))) | |
1927 | #else | |
7006ee24 | 1928 | if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method()))) |
7a8b9519 | 1929 | #endif |
7006ee24 | 1930 | return tls_error(US"SSL_CTX_new", host, NULL, errstr); |
059ec3d9 PH |
1931 | |
1932 | /* It turns out that we need to seed the random number generator this early in | |
1933 | order to get the full complement of ciphers to work. It took me roughly a day | |
1934 | of work to discover this by experiment. | |
1935 | ||
1936 | On systems that have /dev/urandom, SSL may automatically seed itself from | |
1937 | there. Otherwise, we have to make something up as best we can. Double check | |
1938 | afterwards. */ | |
1939 | ||
1940 | if (!RAND_status()) | |
1941 | { | |
1942 | randstuff r; | |
9e3331ea | 1943 | gettimeofday(&r.tv, NULL); |
059ec3d9 PH |
1944 | r.p = getpid(); |
1945 | ||
5903c6ff JH |
1946 | RAND_seed(US (&r), sizeof(r)); |
1947 | RAND_seed(US big_buffer, big_buffer_size); | |
1948 | if (addr != NULL) RAND_seed(US addr, sizeof(addr)); | |
059ec3d9 PH |
1949 | |
1950 | if (!RAND_status()) | |
7199e1ee | 1951 | return tls_error(US"RAND_status", host, |
cf0c6164 | 1952 | US"unable to seed random number generator", errstr); |
059ec3d9 PH |
1953 | } |
1954 | ||
1955 | /* Set up the information callback, which outputs if debugging is at a suitable | |
1956 | level. */ | |
1957 | ||
b10c87b3 JH |
1958 | DEBUG(D_tls) |
1959 | { | |
1960 | SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); | |
e570d136 JH |
1961 | #if defined(EXIM_HAVE_OPESSL_TRACE) && !defined(OPENSSL_NO_SSL_TRACE) |
1962 | /* this needs a debug build of OpenSSL */ | |
b10c87b3 JH |
1963 | SSL_CTX_set_msg_callback(ctx, (void (*)())SSL_trace); |
1964 | #endif | |
8a40db1c | 1965 | #ifdef OPENSSL_HAVE_KEYLOG_CB |
b10c87b3 | 1966 | SSL_CTX_set_keylog_callback(ctx, (void (*)())keylog_callback); |
8a40db1c | 1967 | #endif |
b10c87b3 | 1968 | } |
059ec3d9 | 1969 | |
c80c5570 | 1970 | /* Automatically re-try reads/writes after renegotiation. */ |
7006ee24 | 1971 | (void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY); |
c80c5570 | 1972 | |
77bb000f PP |
1973 | /* Apply administrator-supplied work-arounds. |
1974 | Historically we applied just one requested option, | |
1975 | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we | |
1976 | moved to an administrator-controlled list of options to specify and | |
1977 | grandfathered in the first one as the default value for "openssl_options". | |
059ec3d9 | 1978 | |
77bb000f PP |
1979 | No OpenSSL version number checks: the options we accept depend upon the |
1980 | availability of the option value macros from OpenSSL. */ | |
059ec3d9 | 1981 | |
7006ee24 | 1982 | if (!tls_openssl_options_parse(openssl_options, &init_options)) |
cf0c6164 | 1983 | return tls_error(US"openssl_options parsing failed", host, NULL, errstr); |
77bb000f | 1984 | |
b10c87b3 JH |
1985 | #ifdef EXPERIMENTAL_TLS_RESUME |
1986 | tlsp->resumption = RESUME_SUPPORTED; | |
1987 | #endif | |
77bb000f PP |
1988 | if (init_options) |
1989 | { | |
b10c87b3 JH |
1990 | #ifdef EXPERIMENTAL_TLS_RESUME |
1991 | /* Should the server offer session resumption? */ | |
1992 | if (!host && verify_check_host(&tls_resumption_hosts) == OK) | |
1993 | { | |
1994 | DEBUG(D_tls) debug_printf("tls_resumption_hosts overrides openssl_options\n"); | |
1995 | init_options &= ~SSL_OP_NO_TICKET; | |
1996 | tlsp->resumption |= RESUME_SERVER_TICKET; /* server will give ticket on request */ | |
1997 | tlsp->host_resumable = TRUE; | |
1998 | } | |
1999 | #endif | |
2000 | ||
77bb000f | 2001 | DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options); |
7006ee24 | 2002 | if (!(SSL_CTX_set_options(ctx, init_options))) |
77bb000f | 2003 | return tls_error(string_sprintf( |
cf0c6164 | 2004 | "SSL_CTX_set_option(%#lx)", init_options), host, NULL, errstr); |
77bb000f PP |
2005 | } |
2006 | else | |
2007 | DEBUG(D_tls) debug_printf("no SSL CTX options to set\n"); | |
059ec3d9 | 2008 | |
a28050f8 JH |
2009 | /* We'd like to disable session cache unconditionally, but foolish Outlook |
2010 | Express clients then give up the first TLS connection and make a second one | |
2011 | (which works). Only when there is an IMAP service on the same machine. | |
2012 | Presumably OE is trying to use the cache for A on B. Leave it enabled for | |
2013 | now, until we work out a decent way of presenting control to the config. It | |
2014 | will never be used because we use a new context every time. */ | |
2015 | #ifdef notdef | |
7006ee24 | 2016 | (void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF); |
a28050f8 | 2017 | #endif |
7006ee24 | 2018 | |
059ec3d9 | 2019 | /* Initialize with DH parameters if supplied */ |
10ca4f1c | 2020 | /* Initialize ECDH temp key parameter selection */ |
059ec3d9 | 2021 | |
7006ee24 JH |
2022 | if ( !init_dh(ctx, dhparam, host, errstr) |
2023 | || !init_ecdh(ctx, host, errstr) | |
038597d2 PP |
2024 | ) |
2025 | return DEFER; | |
059ec3d9 | 2026 | |
3f7eeb86 | 2027 | /* Set up certificate and key (and perhaps OCSP info) */ |
059ec3d9 | 2028 | |
7006ee24 | 2029 | if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK) |
23bb6982 | 2030 | return rc; |
c91535f3 | 2031 | |
c3033f13 JH |
2032 | /* If we need to handle SNI or OCSP, do so */ |
2033 | ||
3bcbbbe2 | 2034 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
c3033f13 JH |
2035 | # ifndef DISABLE_OCSP |
2036 | if (!(cbinfo->verify_stack = sk_X509_new_null())) | |
2037 | { | |
2038 | DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n"); | |
2039 | return FAIL; | |
2040 | } | |
2041 | # endif | |
2042 | ||
7a8b9519 | 2043 | if (!host) /* server */ |
3f0945ff | 2044 | { |
f2de3a33 | 2045 | # ifndef DISABLE_OCSP |
f5d78688 | 2046 | /* We check u_ocsp.server.file, not server.response, because we care about if |
3f7eeb86 PP |
2047 | the option exists, not what the current expansion might be, as SNI might |
2048 | change the certificate and OCSP file in use between now and the time the | |
2049 | callback is invoked. */ | |
f5d78688 | 2050 | if (cbinfo->u_ocsp.server.file) |
3f7eeb86 | 2051 | { |
7006ee24 JH |
2052 | SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb); |
2053 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
3f7eeb86 | 2054 | } |
f5d78688 | 2055 | # endif |
3f0945ff PP |
2056 | /* We always do this, so that $tls_sni is available even if not used in |
2057 | tls_certificate */ | |
7006ee24 JH |
2058 | SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); |
2059 | SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo); | |
3f0945ff | 2060 | } |
f2de3a33 | 2061 | # ifndef DISABLE_OCSP |
f5d78688 JH |
2062 | else /* client */ |
2063 | if(ocsp_file) /* wanting stapling */ | |
2064 | { | |
2065 | if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new())) | |
2066 | { | |
2067 | DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n"); | |
2068 | return FAIL; | |
2069 | } | |
7006ee24 JH |
2070 | SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb); |
2071 | SSL_CTX_set_tlsext_status_arg(ctx, cbinfo); | |
f5d78688 JH |
2072 | } |
2073 | # endif | |
7be682ca | 2074 | #endif |
059ec3d9 | 2075 | |
e51c7be2 | 2076 | cbinfo->verify_cert_hostnames = NULL; |
e51c7be2 | 2077 | |
c8dfb21d | 2078 | #ifdef EXIM_HAVE_EPHEM_RSA_KEX |
059ec3d9 | 2079 | /* Set up the RSA callback */ |
7006ee24 | 2080 | SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); |
c8dfb21d | 2081 | #endif |
059ec3d9 | 2082 | |
b10c87b3 JH |
2083 | /* Finally, set the session cache timeout, and we are done. |
2084 | The period appears to be also used for (server-generated) session tickets */ | |
059ec3d9 | 2085 | |
7006ee24 | 2086 | SSL_CTX_set_timeout(ctx, ssl_session_timeout); |
059ec3d9 | 2087 | DEBUG(D_tls) debug_printf("Initialized TLS\n"); |
7be682ca | 2088 | |
817d9f57 | 2089 | *cbp = cbinfo; |
7006ee24 | 2090 | *ctxp = ctx; |
7be682ca | 2091 | |
059ec3d9 PH |
2092 | return OK; |
2093 | } | |
2094 | ||
2095 | ||
2096 | ||
2097 | ||
2098 | /************************************************* | |
2099 | * Get name of cipher in use * | |
2100 | *************************************************/ | |
2101 | ||
817d9f57 | 2102 | /* |
059ec3d9 | 2103 | Argument: pointer to an SSL structure for the connection |
817d9f57 | 2104 | pointer to number of bits for cipher |
f1be21cf | 2105 | Returns: pointer to allocated string in perm-pool |
059ec3d9 PH |
2106 | */ |
2107 | ||
f1be21cf JH |
2108 | static uschar * |
2109 | construct_cipher_name(SSL * ssl, int * bits) | |
059ec3d9 | 2110 | { |
f1be21cf | 2111 | int pool = store_pool; |
7a8b9519 | 2112 | /* With OpenSSL 1.0.0a, 'c' needs to be const but the documentation doesn't |
57b3a7f5 PP |
2113 | yet reflect that. It should be a safe change anyway, even 0.9.8 versions have |
2114 | the accessor functions use const in the prototype. */ | |
059ec3d9 | 2115 | |
7a8b9519 JH |
2116 | const uschar * ver = CUS SSL_get_version(ssl); |
2117 | const SSL_CIPHER * c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); | |
f1be21cf | 2118 | uschar * s; |
059ec3d9 | 2119 | |
817d9f57 | 2120 | SSL_CIPHER_get_bits(c, bits); |
059ec3d9 | 2121 | |
f1be21cf JH |
2122 | store_pool = POOL_PERM; |
2123 | s = string_sprintf("%s:%s:%u", ver, SSL_CIPHER_get_name(c), *bits); | |
2124 | store_pool = pool; | |
2125 | DEBUG(D_tls) debug_printf("Cipher: %s\n", s); | |
2126 | return s; | |
2127 | } | |
2128 | ||
059ec3d9 | 2129 | |
f1be21cf JH |
2130 | /* Get IETF-standard name for ciphersuite. |
2131 | Argument: pointer to an SSL structure for the connection | |
2132 | Returns: pointer to string | |
2133 | */ | |
2134 | ||
2135 | static const uschar * | |
2136 | cipher_stdname_ssl(SSL * ssl) | |
2137 | { | |
2138 | #ifdef EXIM_HAVE_OPENSSL_CIPHER_STD_NAME | |
2139 | return CUS SSL_CIPHER_standard_name(SSL_get_current_cipher(ssl)); | |
2140 | #else | |
2141 | ushort id = 0xffff & SSL_CIPHER_get_id(SSL_get_current_cipher(ssl)); | |
2142 | return cipher_stdname(id >> 8, id & 0xff); | |
2143 | #endif | |
059ec3d9 PH |
2144 | } |
2145 | ||
2146 | ||
f69979cf | 2147 | static void |
70e384dd | 2148 | peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned siz) |
f69979cf JH |
2149 | { |
2150 | /*XXX we might consider a list-of-certs variable for the cert chain. | |
2151 | SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support | |
2152 | in list-handling functions, also consider the difference between the entire | |
2153 | chain and the elements sent by the peer. */ | |
2154 | ||
70e384dd JH |
2155 | tlsp->peerdn = NULL; |
2156 | ||
f69979cf JH |
2157 | /* Will have already noted peercert on a verify fail; possibly not the leaf */ |
2158 | if (!tlsp->peercert) | |
2159 | tlsp->peercert = SSL_get_peer_certificate(ssl); | |
2160 | /* Beware anonymous ciphers which lead to server_cert being NULL */ | |
2161 | if (tlsp->peercert) | |
70e384dd JH |
2162 | if (!X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, siz)) |
2163 | { DEBUG(D_tls) debug_printf("X509_NAME_oneline() error\n"); } | |
2164 | else | |
2165 | { | |
4a1bd6b9 JH |
2166 | int oldpool = store_pool; |
2167 | ||
2168 | peerdn[siz-1] = '\0'; /* paranoia */ | |
2169 | store_pool = POOL_PERM; | |
2170 | tlsp->peerdn = string_copy(peerdn); | |
2171 | store_pool = oldpool; | |
2172 | ||
2173 | /* We used to set CV in the cert-verify callbacks (either plain or dane) | |
2174 | but they don't get called on session-resumption. So use the official | |
2175 | interface, which uses the resumed value. Unfortunately this claims verified | |
2176 | when it actually failed but we're in try-verify mode, due to us wanting the | |
2177 | knowlege that it failed so needing to have the callback and forcing a | |
2178 | permissive return. If we don't force it, the TLS startup is failed. | |
f4e62a87 JH |
2179 | The extra bit of information is set in verify_override in the cb, stashed |
2180 | for resumption next to the TLS session, and used here. */ | |
4a1bd6b9 JH |
2181 | |
2182 | if (!tlsp->verify_override) | |
2183 | tlsp->certificate_verified = SSL_get_verify_result(ssl) == X509_V_OK; | |
70e384dd | 2184 | } |
f69979cf JH |
2185 | } |
2186 | ||
2187 | ||
059ec3d9 PH |
2188 | |
2189 | ||
2190 | ||
2191 | /************************************************* | |
2192 | * Set up for verifying certificates * | |
2193 | *************************************************/ | |
2194 | ||
0e8aed8a | 2195 | #ifndef DISABLE_OCSP |
c3033f13 JH |
2196 | /* Load certs from file, return TRUE on success */ |
2197 | ||
2198 | static BOOL | |
2199 | chain_from_pem_file(const uschar * file, STACK_OF(X509) * verify_stack) | |
2200 | { | |
2201 | BIO * bp; | |
2202 | X509 * x; | |
2203 | ||
dec766a1 WB |
2204 | while (sk_X509_num(verify_stack) > 0) |
2205 | X509_free(sk_X509_pop(verify_stack)); | |
2206 | ||
c3033f13 JH |
2207 | if (!(bp = BIO_new_file(CS file, "r"))) return FALSE; |
2208 | while ((x = PEM_read_bio_X509(bp, NULL, 0, NULL))) | |
2209 | sk_X509_push(verify_stack, x); | |
2210 | BIO_free(bp); | |
2211 | return TRUE; | |
2212 | } | |
0e8aed8a | 2213 | #endif |
c3033f13 JH |
2214 | |
2215 | ||
2216 | ||
dec766a1 WB |
2217 | /* Called by both client and server startup; on the server possibly |
2218 | repeated after a Server Name Indication. | |
059ec3d9 PH |
2219 | |
2220 | Arguments: | |
7be682ca | 2221 | sctx SSL_CTX* to initialise |
059ec3d9 PH |
2222 | certs certs file or NULL |
2223 | crl CRL file or NULL | |
2224 | host NULL in a server; the remote host in a client | |
2225 | optional TRUE if called from a server for a host in tls_try_verify_hosts; | |
2226 | otherwise passed as FALSE | |
983207c1 | 2227 | cert_vfy_cb Callback function for certificate verification |
cf0c6164 | 2228 | errstr error string pointer |
059ec3d9 PH |
2229 | |
2230 | Returns: OK/DEFER/FAIL | |
2231 | */ | |
2232 | ||
2233 | static int | |
983207c1 | 2234 | setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional, |
cf0c6164 | 2235 | int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr) |
059ec3d9 PH |
2236 | { |
2237 | uschar *expcerts, *expcrl; | |
2238 | ||
cf0c6164 | 2239 | if (!expand_check(certs, US"tls_verify_certificates", &expcerts, errstr)) |
059ec3d9 | 2240 | return DEFER; |
57cc2785 | 2241 | DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts); |
059ec3d9 | 2242 | |
10a831a3 | 2243 | if (expcerts && *expcerts) |
059ec3d9 | 2244 | { |
10a831a3 JH |
2245 | /* Tell the library to use its compiled-in location for the system default |
2246 | CA bundle. Then add the ones specified in the config, if any. */ | |
cb1d7830 | 2247 | |
10a831a3 | 2248 | if (!SSL_CTX_set_default_verify_paths(sctx)) |
cf0c6164 | 2249 | return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr); |
10a831a3 JH |
2250 | |
2251 | if (Ustrcmp(expcerts, "system") != 0) | |
059ec3d9 | 2252 | { |
cb1d7830 JH |
2253 | struct stat statbuf; |
2254 | ||
cb1d7830 JH |
2255 | if (Ustat(expcerts, &statbuf) < 0) |
2256 | { | |
2257 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2258 | "failed to stat %s for certificates", expcerts); | |
2259 | return DEFER; | |
2260 | } | |
059ec3d9 | 2261 | else |
059ec3d9 | 2262 | { |
cb1d7830 JH |
2263 | uschar *file, *dir; |
2264 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
2265 | { file = NULL; dir = expcerts; } | |
2266 | else | |
c3033f13 JH |
2267 | { |
2268 | file = expcerts; dir = NULL; | |
2269 | #ifndef DISABLE_OCSP | |
2270 | /* In the server if we will be offering an OCSP proof, load chain from | |
2271 | file for verifying the OCSP proof at load time. */ | |
2272 | ||
2273 | if ( !host | |
2274 | && statbuf.st_size > 0 | |
2275 | && server_static_cbinfo->u_ocsp.server.file | |
2276 | && !chain_from_pem_file(file, server_static_cbinfo->verify_stack) | |
2277 | ) | |
2278 | { | |
2279 | log_write(0, LOG_MAIN|LOG_PANIC, | |
57887ecc | 2280 | "failed to load cert chain from %s", file); |
c3033f13 JH |
2281 | return DEFER; |
2282 | } | |
2283 | #endif | |
2284 | } | |
cb1d7830 JH |
2285 | |
2286 | /* If a certificate file is empty, the next function fails with an | |
2287 | unhelpful error message. If we skip it, we get the correct behaviour (no | |
2288 | certificates are recognized, but the error message is still misleading (it | |
c3033f13 | 2289 | says no certificate was supplied). But this is better. */ |
cb1d7830 | 2290 | |
f2f2c91b JH |
2291 | if ( (!file || statbuf.st_size > 0) |
2292 | && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) | |
cf0c6164 | 2293 | return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr); |
cb1d7830 JH |
2294 | |
2295 | /* Load the list of CAs for which we will accept certs, for sending | |
2296 | to the client. This is only for the one-file tls_verify_certificates | |
2297 | variant. | |
d7978c0f JH |
2298 | If a list isn't loaded into the server, but some verify locations are set, |
2299 | the server end appears to make a wildcard request for client certs. | |
10a831a3 | 2300 | Meanwhile, the client library as default behaviour *ignores* the list |
cb1d7830 JH |
2301 | we send over the wire - see man SSL_CTX_set_client_cert_cb. |
2302 | Because of this, and that the dir variant is likely only used for | |
d7978c0f JH |
2303 | the public-CA bundle (not for a private CA), not worth fixing. */ |
2304 | ||
f2f2c91b | 2305 | if (file) |
cb1d7830 | 2306 | { |
2009ecca | 2307 | STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); |
dec766a1 WB |
2308 | |
2309 | SSL_CTX_set_client_CA_list(sctx, names); | |
f2f2c91b | 2310 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", |
cb1d7830 | 2311 | sk_X509_NAME_num(names)); |
cb1d7830 | 2312 | } |
059ec3d9 PH |
2313 | } |
2314 | } | |
2315 | ||
2316 | /* Handle a certificate revocation list. */ | |
2317 | ||
10a831a3 | 2318 | #if OPENSSL_VERSION_NUMBER > 0x00907000L |
059ec3d9 | 2319 | |
8b417f2c | 2320 | /* This bit of code is now the version supplied by Lars Mainka. (I have |
10a831a3 | 2321 | merely reformatted it into the Exim code style.) |
8b417f2c | 2322 | |
10a831a3 JH |
2323 | "From here I changed the code to add support for multiple crl's |
2324 | in pem format in one file or to support hashed directory entries in | |
2325 | pem format instead of a file. This method now uses the library function | |
2326 | X509_STORE_load_locations to add the CRL location to the SSL context. | |
2327 | OpenSSL will then handle the verify against CA certs and CRLs by | |
2328 | itself in the verify callback." */ | |
8b417f2c | 2329 | |
cf0c6164 | 2330 | if (!expand_check(crl, US"tls_crl", &expcrl, errstr)) return DEFER; |
10a831a3 | 2331 | if (expcrl && *expcrl) |
059ec3d9 | 2332 | { |
8b417f2c PH |
2333 | struct stat statbufcrl; |
2334 | if (Ustat(expcrl, &statbufcrl) < 0) | |
2335 | { | |
2336 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2337 | "failed to stat %s for certificates revocation lists", expcrl); | |
2338 | return DEFER; | |
2339 | } | |
2340 | else | |
059ec3d9 | 2341 | { |
8b417f2c PH |
2342 | /* is it a file or directory? */ |
2343 | uschar *file, *dir; | |
7be682ca | 2344 | X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); |
8b417f2c | 2345 | if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) |
059ec3d9 | 2346 | { |
8b417f2c PH |
2347 | file = NULL; |
2348 | dir = expcrl; | |
2349 | DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir); | |
059ec3d9 PH |
2350 | } |
2351 | else | |
2352 | { | |
8b417f2c PH |
2353 | file = expcrl; |
2354 | dir = NULL; | |
2355 | DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file); | |
059ec3d9 | 2356 | } |
8b417f2c | 2357 | if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0) |
cf0c6164 | 2358 | return tls_error(US"X509_STORE_load_locations", host, NULL, errstr); |
8b417f2c PH |
2359 | |
2360 | /* setting the flags to check against the complete crl chain */ | |
2361 | ||
2362 | X509_STORE_set_flags(cvstore, | |
2363 | X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL); | |
059ec3d9 | 2364 | } |
059ec3d9 PH |
2365 | } |
2366 | ||
10a831a3 | 2367 | #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */ |
059ec3d9 PH |
2368 | |
2369 | /* If verification is optional, don't fail if no certificate */ | |
2370 | ||
7be682ca | 2371 | SSL_CTX_set_verify(sctx, |
5a2a0989 | 2372 | SSL_VERIFY_PEER | (optional ? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), |
983207c1 | 2373 | cert_vfy_cb); |
059ec3d9 PH |
2374 | } |
2375 | ||
2376 | return OK; | |
2377 | } | |
2378 | ||
2379 | ||
2380 | ||
2381 | /************************************************* | |
2382 | * Start a TLS session in a server * | |
2383 | *************************************************/ | |
2384 | ||
2385 | /* This is called when Exim is running as a server, after having received | |
2386 | the STARTTLS command. It must respond to that command, and then negotiate | |
2387 | a TLS session. | |
2388 | ||
2389 | Arguments: | |
2390 | require_ciphers allowed ciphers | |
cf0c6164 | 2391 | errstr pointer to error message |
059ec3d9 PH |
2392 | |
2393 | Returns: OK on success | |
2394 | DEFER for errors before the start of the negotiation | |
4c04137d | 2395 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
2396 | continue running. |
2397 | */ | |
2398 | ||
2399 | int | |
cf0c6164 | 2400 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
2401 | { |
2402 | int rc; | |
cf0c6164 JH |
2403 | uschar * expciphers; |
2404 | tls_ext_ctx_cb * cbinfo; | |
f69979cf | 2405 | static uschar peerdn[256]; |
059ec3d9 PH |
2406 | |
2407 | /* Check for previous activation */ | |
2408 | ||
74f1a423 | 2409 | if (tls_in.active.sock >= 0) |
059ec3d9 | 2410 | { |
cf0c6164 | 2411 | tls_error(US"STARTTLS received after TLS started", NULL, US"", errstr); |
925ac8e4 | 2412 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
2413 | return FAIL; |
2414 | } | |
2415 | ||
2416 | /* Initialize the SSL library. If it fails, it will already have logged | |
2417 | the error. */ | |
2418 | ||
817d9f57 | 2419 | rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, |
f2de3a33 | 2420 | #ifndef DISABLE_OCSP |
47195144 | 2421 | tls_ocsp_file, /*XXX stack*/ |
3f7eeb86 | 2422 | #endif |
b10c87b3 | 2423 | NULL, &server_static_cbinfo, &tls_in, errstr); |
059ec3d9 | 2424 | if (rc != OK) return rc; |
817d9f57 | 2425 | cbinfo = server_static_cbinfo; |
059ec3d9 | 2426 | |
cf0c6164 | 2427 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr)) |
059ec3d9 PH |
2428 | return FAIL; |
2429 | ||
2430 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
17c76198 PP |
2431 | were historically separated by underscores. So that I can use either form in my |
2432 | tests, and also for general convenience, we turn underscores into hyphens here. | |
0c3807a8 JH |
2433 | |
2434 | XXX SSL_CTX_set_cipher_list() is replaced by SSL_CTX_set_ciphersuites() | |
2435 | for TLS 1.3 . Since we do not call it at present we get the default list: | |
2436 | TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256 | |
17c76198 | 2437 | */ |
059ec3d9 | 2438 | |
c3033f13 | 2439 | if (expciphers) |
059ec3d9 | 2440 | { |
b10c87b3 | 2441 | for (uschar * s = expciphers; *s; s++ ) if (*s == '_') *s = '-'; |
059ec3d9 | 2442 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); |
817d9f57 | 2443 | if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers)) |
cf0c6164 | 2444 | return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr); |
7be682ca | 2445 | cbinfo->server_cipher_list = expciphers; |
059ec3d9 PH |
2446 | } |
2447 | ||
2448 | /* If this is a host for which certificate verification is mandatory or | |
2449 | optional, set up appropriately. */ | |
2450 | ||
817d9f57 | 2451 | tls_in.certificate_verified = FALSE; |
c0635b6d | 2452 | #ifdef SUPPORT_DANE |
53a7196b JH |
2453 | tls_in.dane_verified = FALSE; |
2454 | #endif | |
a2ff477a | 2455 | server_verify_callback_called = FALSE; |
059ec3d9 PH |
2456 | |
2457 | if (verify_check_host(&tls_verify_hosts) == OK) | |
2458 | { | |
983207c1 | 2459 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2460 | FALSE, verify_callback_server, errstr); |
059ec3d9 | 2461 | if (rc != OK) return rc; |
a2ff477a | 2462 | server_verify_optional = FALSE; |
059ec3d9 PH |
2463 | } |
2464 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
2465 | { | |
983207c1 | 2466 | rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL, |
afdb5e9c | 2467 | TRUE, verify_callback_server, errstr); |
059ec3d9 | 2468 | if (rc != OK) return rc; |
a2ff477a | 2469 | server_verify_optional = TRUE; |
059ec3d9 PH |
2470 | } |
2471 | ||
b10c87b3 JH |
2472 | #ifdef EXPERIMENTAL_TLS_RESUME |
2473 | SSL_CTX_set_tlsext_ticket_key_cb(server_ctx, ticket_key_callback); | |
2474 | /* despite working, appears to always return failure, so ignoring */ | |
2475 | #endif | |
2476 | #ifdef OPENSSL_HAVE_NUM_TICKETS | |
2477 | # ifdef EXPERIMENTAL_TLS_RESUME | |
2478 | SSL_CTX_set_num_tickets(server_ctx, tls_in.host_resumable ? 1 : 0); | |
2479 | # else | |
2480 | SSL_CTX_set_num_tickets(server_ctx, 0); /* send no TLS1.3 stateful-tickets */ | |
2481 | # endif | |
2482 | #endif | |
2483 | ||
2484 | ||
059ec3d9 PH |
2485 | /* Prepare for new connection */ |
2486 | ||
cf0c6164 JH |
2487 | if (!(server_ssl = SSL_new(server_ctx))) |
2488 | return tls_error(US"SSL_new", NULL, NULL, errstr); | |
da3ad30d PP |
2489 | |
2490 | /* Warning: we used to SSL_clear(ssl) here, it was removed. | |
2491 | * | |
2492 | * With the SSL_clear(), we get strange interoperability bugs with | |
2493 | * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in | |
2494 | * OpenSSL itself, as a clear should not lead to inability to follow protocols. | |
2495 | * | |
2496 | * The SSL_clear() call is to let an existing SSL* be reused, typically after | |
2497 | * session shutdown. In this case, we have a brand new object and there's no | |
2498 | * obvious reason to immediately clear it. I'm guessing that this was | |
2499 | * originally added because of incomplete initialisation which the clear fixed, | |
2500 | * in some historic release. | |
2501 | */ | |
059ec3d9 PH |
2502 | |
2503 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2504 | on connection, where outputting anything now upsets the clients and tends to | |
2505 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2506 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2507 | mode, the fflush() happens when smtp_getc() is called. */ | |
2508 | ||
817d9f57 JH |
2509 | SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx)); |
2510 | if (!tls_in.on_connect) | |
059ec3d9 | 2511 | { |
925ac8e4 | 2512 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
059ec3d9 PH |
2513 | fflush(smtp_out); |
2514 | } | |
2515 | ||
2516 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
2517 | that the OpenSSL library doesn't. */ | |
2518 | ||
817d9f57 JH |
2519 | SSL_set_wfd(server_ssl, fileno(smtp_out)); |
2520 | SSL_set_rfd(server_ssl, fileno(smtp_in)); | |
2521 | SSL_set_accept_state(server_ssl); | |
059ec3d9 PH |
2522 | |
2523 | DEBUG(D_tls) debug_printf("Calling SSL_accept\n"); | |
2524 | ||
2525 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2526 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
817d9f57 | 2527 | rc = SSL_accept(server_ssl); |
c2a1bba0 | 2528 | ALARM_CLR(0); |
059ec3d9 PH |
2529 | |
2530 | if (rc <= 0) | |
2531 | { | |
cf0c6164 | 2532 | (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr); |
059ec3d9 PH |
2533 | return FAIL; |
2534 | } | |
2535 | ||
2536 | DEBUG(D_tls) debug_printf("SSL_accept was successful\n"); | |
25fa0868 | 2537 | ERR_clear_error(); /* Even success can leave errors in the stack. Seen with |
b10c87b3 JH |
2538 | anon-authentication ciphersuite negotiated. */ |
2539 | ||
2540 | #ifdef EXPERIMENTAL_TLS_RESUME | |
2541 | if (SSL_session_reused(server_ssl)) | |
2542 | { | |
2543 | tls_in.resumption |= RESUME_USED; | |
2544 | DEBUG(D_tls) debug_printf("Session reused\n"); | |
2545 | } | |
2546 | #endif | |
059ec3d9 PH |
2547 | |
2548 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2549 | and initialize things. */ | |
2550 | ||
f69979cf JH |
2551 | peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn)); |
2552 | ||
f1be21cf JH |
2553 | tls_in.cipher = construct_cipher_name(server_ssl, &tls_in.bits); |
2554 | tls_in.cipher_stdname = cipher_stdname_ssl(server_ssl); | |
2555 | ||
059ec3d9 PH |
2556 | DEBUG(D_tls) |
2557 | { | |
2558 | uschar buf[2048]; | |
f1be21cf | 2559 | if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf))) |
059ec3d9 | 2560 | debug_printf("Shared ciphers: %s\n", buf); |
f20cfa4a JH |
2561 | |
2562 | #ifdef EXIM_HAVE_OPENSSL_KEYLOG | |
2563 | { | |
10ed27e0 | 2564 | BIO * bp = BIO_new_fp(debug_file, BIO_NOCLOSE); |
f20cfa4a | 2565 | SSL_SESSION_print_keylog(bp, SSL_get_session(server_ssl)); |
f20cfa4a JH |
2566 | BIO_free(bp); |
2567 | } | |
2568 | #endif | |
b10c87b3 JH |
2569 | |
2570 | #ifdef EXIM_HAVE_SESSION_TICKET | |
2571 | { | |
2572 | SSL_SESSION * ss = SSL_get_session(server_ssl); | |
40618fb6 | 2573 | if (SSL_SESSION_has_ticket(ss)) /* 1.1.0 */ |
b10c87b3 JH |
2574 | debug_printf("The session has a ticket, life %lu seconds\n", |
2575 | SSL_SESSION_get_ticket_lifetime_hint(ss)); | |
2576 | } | |
2577 | #endif | |
059ec3d9 PH |
2578 | } |
2579 | ||
9d1c15ef JH |
2580 | /* Record the certificate we presented */ |
2581 | { | |
2582 | X509 * crt = SSL_get_certificate(server_ssl); | |
2583 | tls_in.ourcert = crt ? X509_dup(crt) : NULL; | |
2584 | } | |
059ec3d9 | 2585 | |
817d9f57 JH |
2586 | /* Only used by the server-side tls (tls_in), including tls_getc. |
2587 | Client-side (tls_out) reads (seem to?) go via | |
2588 | smtp_read_response()/ip_recv(). | |
2589 | Hence no need to duplicate for _in and _out. | |
2590 | */ | |
b808677c | 2591 | if (!ssl_xfer_buffer) ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 | 2592 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; |
8b77d27a | 2593 | ssl_xfer_eof = ssl_xfer_error = FALSE; |
059ec3d9 PH |
2594 | |
2595 | receive_getc = tls_getc; | |
0d81dabc | 2596 | receive_getbuf = tls_getbuf; |
584e96c6 | 2597 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2598 | receive_ungetc = tls_ungetc; |
2599 | receive_feof = tls_feof; | |
2600 | receive_ferror = tls_ferror; | |
58eb016e | 2601 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2602 | |
74f1a423 JH |
2603 | tls_in.active.sock = fileno(smtp_out); |
2604 | tls_in.active.tls_ctx = NULL; /* not using explicit ctx for server-side */ | |
059ec3d9 PH |
2605 | return OK; |
2606 | } | |
2607 | ||
2608 | ||
2609 | ||
2610 | ||
043b1248 JH |
2611 | static int |
2612 | tls_client_basic_ctx_init(SSL_CTX * ctx, | |
cf0c6164 JH |
2613 | host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo, |
2614 | uschar ** errstr) | |
043b1248 JH |
2615 | { |
2616 | int rc; | |
94431adb | 2617 | /* stick to the old behaviour for compatibility if tls_verify_certificates is |
043b1248 JH |
2618 | set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only |
2619 | the specified host patterns if one of them is defined */ | |
2620 | ||
610ff438 JH |
2621 | if ( ( !ob->tls_verify_hosts |
2622 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2623 | ) | |
3c07dd2d | 2624 | || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK |
aa2a70ba | 2625 | ) |
043b1248 | 2626 | client_verify_optional = FALSE; |
3c07dd2d | 2627 | else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) |
aa2a70ba JH |
2628 | client_verify_optional = TRUE; |
2629 | else | |
2630 | return OK; | |
2631 | ||
2632 | if ((rc = setup_certs(ctx, ob->tls_verify_certificates, | |
cf0c6164 JH |
2633 | ob->tls_crl, host, client_verify_optional, verify_callback_client, |
2634 | errstr)) != OK) | |
aa2a70ba | 2635 | return rc; |
043b1248 | 2636 | |
3c07dd2d | 2637 | if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) |
043b1248 | 2638 | { |
4af0d74a | 2639 | cbinfo->verify_cert_hostnames = |
8c5d388a | 2640 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2641 | string_domain_utf8_to_alabel(host->name, NULL); |
2642 | #else | |
2643 | host->name; | |
2644 | #endif | |
aa2a70ba JH |
2645 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", |
2646 | cbinfo->verify_cert_hostnames); | |
043b1248 | 2647 | } |
043b1248 JH |
2648 | return OK; |
2649 | } | |
059ec3d9 | 2650 | |
fde080a4 | 2651 | |
c0635b6d | 2652 | #ifdef SUPPORT_DANE |
fde080a4 | 2653 | static int |
cf0c6164 | 2654 | dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa, uschar ** errstr) |
fde080a4 | 2655 | { |
fde080a4 JH |
2656 | dns_scan dnss; |
2657 | const char * hostnames[2] = { CS host->name, NULL }; | |
2658 | int found = 0; | |
2659 | ||
2660 | if (DANESSL_init(ssl, NULL, hostnames) != 1) | |
cf0c6164 | 2661 | return tls_error(US"hostnames load", host, NULL, errstr); |
fde080a4 | 2662 | |
d7978c0f | 2663 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; |
fde080a4 | 2664 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
1b76ad22 | 2665 | ) if (rr->type == T_TLSA && rr->size > 3) |
fde080a4 | 2666 | { |
c3033f13 | 2667 | const uschar * p = rr->data; |
fde080a4 JH |
2668 | uint8_t usage, selector, mtype; |
2669 | const char * mdname; | |
2670 | ||
fde080a4 | 2671 | usage = *p++; |
133d2546 JH |
2672 | |
2673 | /* Only DANE-TA(2) and DANE-EE(3) are supported */ | |
2674 | if (usage != 2 && usage != 3) continue; | |
2675 | ||
fde080a4 JH |
2676 | selector = *p++; |
2677 | mtype = *p++; | |
2678 | ||
2679 | switch (mtype) | |
2680 | { | |
133d2546 JH |
2681 | default: continue; /* Only match-types 0, 1, 2 are supported */ |
2682 | case 0: mdname = NULL; break; | |
2683 | case 1: mdname = "sha256"; break; | |
2684 | case 2: mdname = "sha512"; break; | |
fde080a4 JH |
2685 | } |
2686 | ||
133d2546 | 2687 | found++; |
fde080a4 JH |
2688 | switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) |
2689 | { | |
2690 | default: | |
cf0c6164 | 2691 | return tls_error(US"tlsa load", host, NULL, errstr); |
c035b645 | 2692 | case 0: /* action not taken */ |
fde080a4 JH |
2693 | case 1: break; |
2694 | } | |
594706ea JH |
2695 | |
2696 | tls_out.tlsa_usage |= 1<<usage; | |
fde080a4 JH |
2697 | } |
2698 | ||
2699 | if (found) | |
2700 | return OK; | |
2701 | ||
133d2546 | 2702 | log_write(0, LOG_MAIN, "DANE error: No usable TLSA records"); |
6ebd79ec | 2703 | return DEFER; |
fde080a4 | 2704 | } |
c0635b6d | 2705 | #endif /*SUPPORT_DANE*/ |
fde080a4 JH |
2706 | |
2707 | ||
2708 | ||
b10c87b3 JH |
2709 | #ifdef EXPERIMENTAL_TLS_RESUME |
2710 | /* On the client, get any stashed session for the given IP from hints db | |
2711 | and apply it to the ssl-connection for attempted resumption. */ | |
2712 | ||
2713 | static void | |
2714 | tls_retrieve_session(tls_support * tlsp, SSL * ssl, const uschar * key) | |
2715 | { | |
2716 | tlsp->resumption |= RESUME_SUPPORTED; | |
2717 | if (tlsp->host_resumable) | |
2718 | { | |
2719 | dbdata_tls_session * dt; | |
2720 | int len; | |
2721 | open_db dbblock, * dbm_file; | |
2722 | ||
2723 | tlsp->resumption |= RESUME_CLIENT_REQUESTED; | |
2724 | DEBUG(D_tls) debug_printf("checking for resumable session for %s\n", key); | |
2725 | if ((dbm_file = dbfn_open(US"tls", O_RDONLY, &dbblock, FALSE, FALSE))) | |
2726 | { | |
2727 | /* key for the db is the IP */ | |
2728 | if ((dt = dbfn_read_with_length(dbm_file, key, &len))) | |
2729 | { | |
2730 | SSL_SESSION * ss = NULL; | |
2731 | const uschar * sess_asn1 = dt->session; | |
2732 | ||
2733 | len -= sizeof(dbdata_tls_session); | |
2734 | if (!(d2i_SSL_SESSION(&ss, &sess_asn1, (long)len))) | |
2735 | { | |
2736 | DEBUG(D_tls) | |
2737 | { | |
2738 | ERR_error_string_n(ERR_get_error(), | |
2739 | ssl_errstring, sizeof(ssl_errstring)); | |
2740 | debug_printf("decoding session: %s\n", ssl_errstring); | |
2741 | } | |
2742 | } | |
a775dd1d | 2743 | #ifdef EXIM_HAVE_SESSION_TICKET |
4f1d23a1 JH |
2744 | else if ( SSL_SESSION_get_ticket_lifetime_hint(ss) + dt->time_stamp |
2745 | < time(NULL)) | |
2746 | { | |
2747 | DEBUG(D_tls) debug_printf("session expired\n"); | |
2748 | dbfn_delete(dbm_file, key); | |
2749 | } | |
a775dd1d | 2750 | #endif |
b10c87b3 JH |
2751 | else if (!SSL_set_session(ssl, ss)) |
2752 | { | |
2753 | DEBUG(D_tls) | |
2754 | { | |
2755 | ERR_error_string_n(ERR_get_error(), | |
2756 | ssl_errstring, sizeof(ssl_errstring)); | |
2757 | debug_printf("applying session to ssl: %s\n", ssl_errstring); | |
2758 | } | |
2759 | } | |
2760 | else | |
2761 | { | |
2762 | DEBUG(D_tls) debug_printf("good session\n"); | |
2763 | tlsp->resumption |= RESUME_CLIENT_SUGGESTED; | |
f4e62a87 | 2764 | tlsp->verify_override = dt->verify_override; |
c82de233 | 2765 | tlsp->ocsp = dt->ocsp; |
b10c87b3 JH |
2766 | } |
2767 | } | |
2768 | else | |
2769 | DEBUG(D_tls) debug_printf("no session record\n"); | |
2770 | dbfn_close(dbm_file); | |
2771 | } | |
2772 | } | |
2773 | } | |
2774 | ||
2775 | ||
2776 | /* On the client, save the session for later resumption */ | |
2777 | ||
2778 | static int | |
2779 | tls_save_session_cb(SSL * ssl, SSL_SESSION * ss) | |
2780 | { | |
2781 | tls_ext_ctx_cb * cbinfo = SSL_get_ex_data(ssl, tls_exdata_idx); | |
2782 | tls_support * tlsp; | |
2783 | ||
2784 | DEBUG(D_tls) debug_printf("tls_save_session_cb\n"); | |
2785 | ||
2786 | if (!cbinfo || !(tlsp = cbinfo->tlsp)->host_resumable) return 0; | |
2787 | ||
40618fb6 JH |
2788 | # ifdef OPENSSL_HAVE_NUM_TICKETS |
2789 | if (SSL_SESSION_is_resumable(ss)) /* 1.1.1 */ | |
2790 | # endif | |
b10c87b3 JH |
2791 | { |
2792 | int len = i2d_SSL_SESSION(ss, NULL); | |
2793 | int dlen = sizeof(dbdata_tls_session) + len; | |
f3ebb786 | 2794 | dbdata_tls_session * dt = store_get(dlen, TRUE); |
b10c87b3 JH |
2795 | uschar * s = dt->session; |
2796 | open_db dbblock, * dbm_file; | |
2797 | ||
2798 | DEBUG(D_tls) debug_printf("session is resumable\n"); | |
2799 | tlsp->resumption |= RESUME_SERVER_TICKET; /* server gave us a ticket */ | |
2800 | ||
f4e62a87 | 2801 | dt->verify_override = tlsp->verify_override; |
c82de233 | 2802 | dt->ocsp = tlsp->ocsp; |
f4e62a87 | 2803 | (void) i2d_SSL_SESSION(ss, &s); /* s gets bumped to end */ |
b10c87b3 JH |
2804 | |
2805 | if ((dbm_file = dbfn_open(US"tls", O_RDWR, &dbblock, FALSE, FALSE))) | |
2806 | { | |
2807 | const uschar * key = cbinfo->host->address; | |
2808 | dbfn_delete(dbm_file, key); | |
2809 | dbfn_write(dbm_file, key, dt, dlen); | |
2810 | dbfn_close(dbm_file); | |
2811 | DEBUG(D_tls) debug_printf("wrote session (len %u) to db\n", | |
2812 | (unsigned)dlen); | |
2813 | } | |
2814 | } | |
b10c87b3 JH |
2815 | return 1; |
2816 | } | |
2817 | ||
2818 | ||
2819 | static void | |
2820 | tls_client_ctx_resume_prehandshake( | |
2821 | exim_openssl_client_tls_ctx * exim_client_ctx, tls_support * tlsp, | |
2822 | smtp_transport_options_block * ob, host_item * host) | |
2823 | { | |
2824 | /* Should the client request a session resumption ticket? */ | |
2825 | if (verify_check_given_host(CUSS &ob->tls_resumption_hosts, host) == OK) | |
2826 | { | |
2827 | tlsp->host_resumable = TRUE; | |
2828 | ||
2829 | SSL_CTX_set_session_cache_mode(exim_client_ctx->ctx, | |
2830 | SSL_SESS_CACHE_CLIENT | |
2831 | | SSL_SESS_CACHE_NO_INTERNAL | SSL_SESS_CACHE_NO_AUTO_CLEAR); | |
2832 | SSL_CTX_sess_set_new_cb(exim_client_ctx->ctx, tls_save_session_cb); | |
2833 | } | |
2834 | } | |
2835 | ||
2836 | static BOOL | |
2837 | tls_client_ssl_resume_prehandshake(SSL * ssl, tls_support * tlsp, | |
2838 | host_item * host, uschar ** errstr) | |
2839 | { | |
2840 | if (tlsp->host_resumable) | |
2841 | { | |
2842 | DEBUG(D_tls) | |
2843 | debug_printf("tls_resumption_hosts overrides openssl_options, enabling tickets\n"); | |
2844 | SSL_clear_options(ssl, SSL_OP_NO_TICKET); | |
2845 | ||
2846 | tls_exdata_idx = SSL_get_ex_new_index(0, 0, 0, 0, 0); | |
2847 | if (!SSL_set_ex_data(ssl, tls_exdata_idx, client_static_cbinfo)) | |
2848 | { | |
2849 | tls_error(US"set ex_data", host, NULL, errstr); | |
2850 | return FALSE; | |
2851 | } | |
2852 | debug_printf("tls_exdata_idx %d cbinfo %p\n", tls_exdata_idx, client_static_cbinfo); | |
2853 | } | |
2854 | ||
2855 | tlsp->resumption = RESUME_SUPPORTED; | |
2856 | /* Pick up a previous session, saved on an old ticket */ | |
2857 | tls_retrieve_session(tlsp, ssl, host->address); | |
2858 | return TRUE; | |
2859 | } | |
2860 | ||
2861 | static void | |
2862 | tls_client_resume_posthandshake(exim_openssl_client_tls_ctx * exim_client_ctx, | |
2863 | tls_support * tlsp) | |
2864 | { | |
2865 | if (SSL_session_reused(exim_client_ctx->ssl)) | |
2866 | { | |
2867 | DEBUG(D_tls) debug_printf("The session was reused\n"); | |
2868 | tlsp->resumption |= RESUME_USED; | |
2869 | } | |
2870 | } | |
2871 | #endif /* EXPERIMENTAL_TLS_RESUME */ | |
2872 | ||
2873 | ||
059ec3d9 PH |
2874 | /************************************************* |
2875 | * Start a TLS session in a client * | |
2876 | *************************************************/ | |
2877 | ||
2878 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2879 | ||
c05bdbd6 JH |
2880 | Arguments: |
2881 | cctx connection context | |
2882 | conn_args connection details | |
2883 | cookie datum for randomness; can be NULL | |
2884 | tlsp record details of TLS channel configuration here; must be non-NULL | |
2885 | errstr error string pointer | |
2886 | ||
2887 | Returns: TRUE for success with TLS session context set in connection context, | |
2888 | FALSE on error | |
059ec3d9 PH |
2889 | */ |
2890 | ||
c05bdbd6 JH |
2891 | BOOL |
2892 | tls_client_start(client_conn_ctx * cctx, smtp_connect_args * conn_args, | |
2893 | void * cookie, tls_support * tlsp, uschar ** errstr) | |
059ec3d9 | 2894 | { |
c05bdbd6 JH |
2895 | host_item * host = conn_args->host; /* for msgs and option-tests */ |
2896 | transport_instance * tb = conn_args->tblock; /* always smtp or NULL */ | |
afdb5e9c JH |
2897 | smtp_transport_options_block * ob = tb |
2898 | ? (smtp_transport_options_block *)tb->options_block | |
2899 | : &smtp_transport_option_defaults; | |
74f1a423 | 2900 | exim_openssl_client_tls_ctx * exim_client_ctx; |
868f5672 | 2901 | uschar * expciphers; |
059ec3d9 | 2902 | int rc; |
c05bdbd6 | 2903 | static uschar peerdn[256]; |
043b1248 JH |
2904 | |
2905 | #ifndef DISABLE_OCSP | |
043b1248 | 2906 | BOOL request_ocsp = FALSE; |
6634ac8d | 2907 | BOOL require_ocsp = FALSE; |
043b1248 | 2908 | #endif |
043b1248 | 2909 | |
74f1a423 JH |
2910 | rc = store_pool; |
2911 | store_pool = POOL_PERM; | |
f3ebb786 | 2912 | exim_client_ctx = store_get(sizeof(exim_openssl_client_tls_ctx), FALSE); |
c09dbcfb | 2913 | exim_client_ctx->corked = NULL; |
74f1a423 JH |
2914 | store_pool = rc; |
2915 | ||
c0635b6d | 2916 | #ifdef SUPPORT_DANE |
74f1a423 | 2917 | tlsp->tlsa_usage = 0; |
043b1248 JH |
2918 | #endif |
2919 | ||
f2de3a33 | 2920 | #ifndef DISABLE_OCSP |
043b1248 | 2921 | { |
c0635b6d | 2922 | # ifdef SUPPORT_DANE |
c05bdbd6 | 2923 | if ( conn_args->dane |
4f59c424 JH |
2924 | && ob->hosts_request_ocsp[0] == '*' |
2925 | && ob->hosts_request_ocsp[1] == '\0' | |
2926 | ) | |
2927 | { | |
2928 | /* Unchanged from default. Use a safer one under DANE */ | |
2929 | request_ocsp = TRUE; | |
2930 | ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " | |
2931 | " {= {4}{$tls_out_tlsa_usage}} } " | |
2932 | " {*}{}}"; | |
2933 | } | |
2934 | # endif | |
2935 | ||
5130845b | 2936 | if ((require_ocsp = |
3c07dd2d | 2937 | verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK)) |
fca41d5a JH |
2938 | request_ocsp = TRUE; |
2939 | else | |
c0635b6d | 2940 | # ifdef SUPPORT_DANE |
4f59c424 | 2941 | if (!request_ocsp) |
fca41d5a | 2942 | # endif |
5130845b | 2943 | request_ocsp = |
3c07dd2d | 2944 | verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
043b1248 | 2945 | } |
f5d78688 | 2946 | #endif |
059ec3d9 | 2947 | |
74f1a423 | 2948 | rc = tls_init(&exim_client_ctx->ctx, host, NULL, |
65867078 | 2949 | ob->tls_certificate, ob->tls_privatekey, |
f2de3a33 | 2950 | #ifndef DISABLE_OCSP |
44662487 | 2951 | (void *)(long)request_ocsp, |
3f7eeb86 | 2952 | #endif |
b10c87b3 | 2953 | cookie, &client_static_cbinfo, tlsp, errstr); |
c05bdbd6 | 2954 | if (rc != OK) return FALSE; |
059ec3d9 | 2955 | |
74f1a423 | 2956 | tlsp->certificate_verified = FALSE; |
a2ff477a | 2957 | client_verify_callback_called = FALSE; |
059ec3d9 | 2958 | |
5ec37a55 PP |
2959 | expciphers = NULL; |
2960 | #ifdef SUPPORT_DANE | |
c05bdbd6 | 2961 | if (conn_args->dane) |
5ec37a55 PP |
2962 | { |
2963 | /* We fall back to tls_require_ciphers if unset, empty or forced failure, but | |
2964 | other failures should be treated as problems. */ | |
2965 | if (ob->dane_require_tls_ciphers && | |
2966 | !expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2967 | &expciphers, errstr)) | |
c05bdbd6 | 2968 | return FALSE; |
5ec37a55 PP |
2969 | if (expciphers && *expciphers == '\0') |
2970 | expciphers = NULL; | |
2971 | } | |
2972 | #endif | |
2973 | if (!expciphers && | |
2974 | !expand_check(ob->tls_require_ciphers, US"tls_require_ciphers", | |
2975 | &expciphers, errstr)) | |
c05bdbd6 | 2976 | return FALSE; |
059ec3d9 PH |
2977 | |
2978 | /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they | |
2979 | are separated by underscores. So that I can use either form in my tests, and | |
2980 | also for general convenience, we turn underscores into hyphens here. */ | |
2981 | ||
cf0c6164 | 2982 | if (expciphers) |
059ec3d9 PH |
2983 | { |
2984 | uschar *s = expciphers; | |
cf0c6164 | 2985 | while (*s) { if (*s == '_') *s = '-'; s++; } |
059ec3d9 | 2986 | DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); |
74f1a423 JH |
2987 | if (!SSL_CTX_set_cipher_list(exim_client_ctx->ctx, CS expciphers)) |
2988 | { | |
2989 | tls_error(US"SSL_CTX_set_cipher_list", host, NULL, errstr); | |
c05bdbd6 | 2990 | return FALSE; |
74f1a423 | 2991 | } |
059ec3d9 PH |
2992 | } |
2993 | ||
c0635b6d | 2994 | #ifdef SUPPORT_DANE |
c05bdbd6 | 2995 | if (conn_args->dane) |
a63be306 | 2996 | { |
74f1a423 | 2997 | SSL_CTX_set_verify(exim_client_ctx->ctx, |
02af313d JH |
2998 | SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, |
2999 | verify_callback_client_dane); | |
e5cccda9 | 3000 | |
043b1248 | 3001 | if (!DANESSL_library_init()) |
74f1a423 JH |
3002 | { |
3003 | tls_error(US"library init", host, NULL, errstr); | |
c05bdbd6 | 3004 | return FALSE; |
74f1a423 JH |
3005 | } |
3006 | if (DANESSL_CTX_init(exim_client_ctx->ctx) <= 0) | |
3007 | { | |
3008 | tls_error(US"context init", host, NULL, errstr); | |
c05bdbd6 | 3009 | return FALSE; |
74f1a423 | 3010 | } |
043b1248 JH |
3011 | } |
3012 | else | |
e51c7be2 | 3013 | |
043b1248 JH |
3014 | #endif |
3015 | ||
74f1a423 JH |
3016 | if (tls_client_basic_ctx_init(exim_client_ctx->ctx, host, ob, |
3017 | client_static_cbinfo, errstr) != OK) | |
c05bdbd6 | 3018 | return FALSE; |
059ec3d9 | 3019 | |
b10c87b3 JH |
3020 | #ifdef EXPERIMENTAL_TLS_RESUME |
3021 | tls_client_ctx_resume_prehandshake(exim_client_ctx, tlsp, ob, host); | |
3022 | #endif | |
3023 | ||
3024 | ||
74f1a423 JH |
3025 | if (!(exim_client_ctx->ssl = SSL_new(exim_client_ctx->ctx))) |
3026 | { | |
3027 | tls_error(US"SSL_new", host, NULL, errstr); | |
c05bdbd6 | 3028 | return FALSE; |
74f1a423 JH |
3029 | } |
3030 | SSL_set_session_id_context(exim_client_ctx->ssl, sid_ctx, Ustrlen(sid_ctx)); | |
b10c87b3 | 3031 | |
c05bdbd6 | 3032 | SSL_set_fd(exim_client_ctx->ssl, cctx->sock); |
74f1a423 | 3033 | SSL_set_connect_state(exim_client_ctx->ssl); |
059ec3d9 | 3034 | |
65867078 | 3035 | if (ob->tls_sni) |
3f0945ff | 3036 | { |
74f1a423 | 3037 | if (!expand_check(ob->tls_sni, US"tls_sni", &tlsp->sni, errstr)) |
c05bdbd6 | 3038 | return FALSE; |
74f1a423 | 3039 | if (!tlsp->sni) |
2c9a0e86 PP |
3040 | { |
3041 | DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n"); | |
3042 | } | |
74f1a423 JH |
3043 | else if (!Ustrlen(tlsp->sni)) |
3044 | tlsp->sni = NULL; | |
3f0945ff PP |
3045 | else |
3046 | { | |
35731706 | 3047 | #ifdef EXIM_HAVE_OPENSSL_TLSEXT |
74f1a423 JH |
3048 | DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tlsp->sni); |
3049 | SSL_set_tlsext_host_name(exim_client_ctx->ssl, tlsp->sni); | |
35731706 | 3050 | #else |
66802652 | 3051 | log_write(0, LOG_MAIN, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n", |
74f1a423 | 3052 | tlsp->sni); |
35731706 | 3053 | #endif |
3f0945ff PP |
3054 | } |
3055 | } | |
3056 | ||
c0635b6d | 3057 | #ifdef SUPPORT_DANE |
c05bdbd6 JH |
3058 | if (conn_args->dane) |
3059 | if (dane_tlsa_load(exim_client_ctx->ssl, host, &conn_args->tlsa_dnsa, errstr) != OK) | |
3060 | return FALSE; | |
594706ea JH |
3061 | #endif |
3062 | ||
f2de3a33 | 3063 | #ifndef DISABLE_OCSP |
f5d78688 JH |
3064 | /* Request certificate status at connection-time. If the server |
3065 | does OCSP stapling we will get the callback (set in tls_init()) */ | |
c0635b6d | 3066 | # ifdef SUPPORT_DANE |
594706ea JH |
3067 | if (request_ocsp) |
3068 | { | |
3069 | const uschar * s; | |
41afb5cb JH |
3070 | if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) |
3071 | || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) | |
594706ea JH |
3072 | ) |
3073 | { /* Re-eval now $tls_out_tlsa_usage is populated. If | |
3074 | this means we avoid the OCSP request, we wasted the setup | |
3075 | cost in tls_init(). */ | |
3c07dd2d | 3076 | require_ocsp = verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; |
5130845b | 3077 | request_ocsp = require_ocsp |
3c07dd2d | 3078 | || verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
594706ea JH |
3079 | } |
3080 | } | |
b50c8b84 JH |
3081 | # endif |
3082 | ||
44662487 JH |
3083 | if (request_ocsp) |
3084 | { | |
74f1a423 | 3085 | SSL_set_tlsext_status_type(exim_client_ctx->ssl, TLSEXT_STATUSTYPE_ocsp); |
44662487 | 3086 | client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp; |
74f1a423 | 3087 | tlsp->ocsp = OCSP_NOT_RESP; |
44662487 | 3088 | } |
f5d78688 JH |
3089 | #endif |
3090 | ||
c82de233 JH |
3091 | #ifdef EXPERIMENTAL_TLS_RESUME |
3092 | if (!tls_client_ssl_resume_prehandshake(exim_client_ctx->ssl, tlsp, host, | |
3093 | errstr)) | |
3094 | return FALSE; | |
3095 | #endif | |
3096 | ||
0cbf2b82 | 3097 | #ifndef DISABLE_EVENT |
afdb5e9c | 3098 | client_static_cbinfo->event_action = tb ? tb->event_action : NULL; |
a7538db1 | 3099 | #endif |
043b1248 | 3100 | |
059ec3d9 PH |
3101 | /* There doesn't seem to be a built-in timeout on connection. */ |
3102 | ||
3103 | DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); | |
3104 | sigalrm_seen = FALSE; | |
c2a1bba0 | 3105 | ALARM(ob->command_timeout); |
74f1a423 | 3106 | rc = SSL_connect(exim_client_ctx->ssl); |
c2a1bba0 | 3107 | ALARM_CLR(0); |
059ec3d9 | 3108 | |
c0635b6d | 3109 | #ifdef SUPPORT_DANE |
c05bdbd6 | 3110 | if (conn_args->dane) |
74f1a423 | 3111 | DANESSL_cleanup(exim_client_ctx->ssl); |
043b1248 JH |
3112 | #endif |
3113 | ||
059ec3d9 | 3114 | if (rc <= 0) |
74f1a423 JH |
3115 | { |
3116 | tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL, errstr); | |
c05bdbd6 | 3117 | return FALSE; |
74f1a423 | 3118 | } |
059ec3d9 | 3119 | |
f20cfa4a JH |
3120 | DEBUG(D_tls) |
3121 | { | |
3122 | debug_printf("SSL_connect succeeded\n"); | |
3123 | #ifdef EXIM_HAVE_OPENSSL_KEYLOG | |
3124 | { | |
10ed27e0 JH |
3125 | BIO * bp = BIO_new_fp(debug_file, BIO_NOCLOSE); |
3126 | SSL_SESSION_print_keylog(bp, SSL_get_session(exim_client_ctx->ssl)); | |
3127 | BIO_free(bp); | |
f20cfa4a JH |
3128 | } |
3129 | #endif | |
3130 | } | |
059ec3d9 | 3131 | |
b10c87b3 JH |
3132 | #ifdef EXPERIMENTAL_TLS_RESUME |
3133 | tls_client_resume_posthandshake(exim_client_ctx, tlsp); | |
3134 | #endif | |
3135 | ||
74f1a423 | 3136 | peer_cert(exim_client_ctx->ssl, tlsp, peerdn, sizeof(peerdn)); |
059ec3d9 | 3137 | |
f1be21cf JH |
3138 | tlsp->cipher = construct_cipher_name(exim_client_ctx->ssl, &tlsp->bits); |
3139 | tlsp->cipher_stdname = cipher_stdname_ssl(exim_client_ctx->ssl); | |
059ec3d9 | 3140 | |
9d1c15ef JH |
3141 | /* Record the certificate we presented */ |
3142 | { | |
74f1a423 JH |
3143 | X509 * crt = SSL_get_certificate(exim_client_ctx->ssl); |
3144 | tlsp->ourcert = crt ? X509_dup(crt) : NULL; | |
9d1c15ef JH |
3145 | } |
3146 | ||
c05bdbd6 | 3147 | tlsp->active.sock = cctx->sock; |
74f1a423 | 3148 | tlsp->active.tls_ctx = exim_client_ctx; |
c05bdbd6 JH |
3149 | cctx->tls_ctx = exim_client_ctx; |
3150 | return TRUE; | |
059ec3d9 PH |
3151 | } |
3152 | ||
3153 | ||
3154 | ||
3155 | ||
3156 | ||
0d81dabc JH |
3157 | static BOOL |
3158 | tls_refill(unsigned lim) | |
3159 | { | |
3160 | int error; | |
3161 | int inbytes; | |
3162 | ||
3163 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl, | |
3164 | ssl_xfer_buffer, ssl_xfer_buffer_size); | |
3165 | ||
c2a1bba0 | 3166 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
0d81dabc JH |
3167 | inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer, |
3168 | MIN(ssl_xfer_buffer_size, lim)); | |
3169 | error = SSL_get_error(server_ssl, inbytes); | |
c2a1bba0 | 3170 | if (smtp_receive_timeout > 0) ALARM_CLR(0); |
9723f966 JH |
3171 | |
3172 | if (had_command_timeout) /* set by signal handler */ | |
3173 | smtp_command_timeout_exit(); /* does not return */ | |
3174 | if (had_command_sigterm) | |
3175 | smtp_command_sigterm_exit(); | |
3176 | if (had_data_timeout) | |
3177 | smtp_data_timeout_exit(); | |
3178 | if (had_data_sigint) | |
3179 | smtp_data_sigint_exit(); | |
0d81dabc JH |
3180 | |
3181 | /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been | |
3182 | closed down, not that the socket itself has been closed down. Revert to | |
3183 | non-SSL handling. */ | |
3184 | ||
74f1a423 | 3185 | switch(error) |
0d81dabc | 3186 | { |
74f1a423 JH |
3187 | case SSL_ERROR_NONE: |
3188 | break; | |
3189 | ||
3190 | case SSL_ERROR_ZERO_RETURN: | |
3191 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
0d81dabc | 3192 | |
74f1a423 JH |
3193 | if (SSL_get_shutdown(server_ssl) == SSL_RECEIVED_SHUTDOWN) |
3194 | SSL_shutdown(server_ssl); | |
dec766a1 | 3195 | |
bd231acd | 3196 | tls_close(NULL, TLS_NO_SHUTDOWN); |
74f1a423 | 3197 | return FALSE; |
0d81dabc | 3198 | |
74f1a423 JH |
3199 | /* Handle genuine errors */ |
3200 | case SSL_ERROR_SSL: | |
0abc5a13 | 3201 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
74f1a423 JH |
3202 | log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring); |
3203 | ssl_xfer_error = TRUE; | |
3204 | return FALSE; | |
0d81dabc | 3205 | |
74f1a423 JH |
3206 | default: |
3207 | DEBUG(D_tls) debug_printf("Got SSL error %d\n", error); | |
3208 | DEBUG(D_tls) if (error == SSL_ERROR_SYSCALL) | |
3209 | debug_printf(" - syscall %s\n", strerror(errno)); | |
3210 | ssl_xfer_error = TRUE; | |
3211 | return FALSE; | |
0d81dabc JH |
3212 | } |
3213 | ||
3214 | #ifndef DISABLE_DKIM | |
3215 | dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); | |
3216 | #endif | |
3217 | ssl_xfer_buffer_hwm = inbytes; | |
3218 | ssl_xfer_buffer_lwm = 0; | |
3219 | return TRUE; | |
3220 | } | |
3221 | ||
3222 | ||
059ec3d9 PH |
3223 | /************************************************* |
3224 | * TLS version of getc * | |
3225 | *************************************************/ | |
3226 | ||
3227 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
3228 | it refills the buffer via the SSL reading function. | |
3229 | ||
bd8fbe36 | 3230 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 | 3231 | Returns: the next character or EOF |
817d9f57 JH |
3232 | |
3233 | Only used by the server-side TLS. | |
059ec3d9 PH |
3234 | */ |
3235 | ||
3236 | int | |
bd8fbe36 | 3237 | tls_getc(unsigned lim) |
059ec3d9 PH |
3238 | { |
3239 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
0d81dabc JH |
3240 | if (!tls_refill(lim)) |
3241 | return ssl_xfer_error ? EOF : smtp_getc(lim); | |
059ec3d9 | 3242 | |
0d81dabc | 3243 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 3244 | |
0d81dabc JH |
3245 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; |
3246 | } | |
059ec3d9 | 3247 | |
0d81dabc JH |
3248 | uschar * |
3249 | tls_getbuf(unsigned * len) | |
3250 | { | |
3251 | unsigned size; | |
3252 | uschar * buf; | |
ba084640 | 3253 | |
0d81dabc JH |
3254 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) |
3255 | if (!tls_refill(*len)) | |
059ec3d9 | 3256 | { |
0d81dabc JH |
3257 | if (!ssl_xfer_error) return smtp_getbuf(len); |
3258 | *len = 0; | |
3259 | return NULL; | |
059ec3d9 | 3260 | } |
c80c5570 | 3261 | |
0d81dabc JH |
3262 | if ((size = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm) > *len) |
3263 | size = *len; | |
3264 | buf = &ssl_xfer_buffer[ssl_xfer_buffer_lwm]; | |
3265 | ssl_xfer_buffer_lwm += size; | |
3266 | *len = size; | |
3267 | return buf; | |
059ec3d9 PH |
3268 | } |
3269 | ||
0d81dabc | 3270 | |
584e96c6 JH |
3271 | void |
3272 | tls_get_cache() | |
3273 | { | |
9960d1e5 | 3274 | #ifndef DISABLE_DKIM |
584e96c6 JH |
3275 | int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm; |
3276 | if (n > 0) | |
3277 | dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n); | |
584e96c6 | 3278 | #endif |
9960d1e5 | 3279 | } |
584e96c6 | 3280 | |
059ec3d9 | 3281 | |
925ac8e4 JH |
3282 | BOOL |
3283 | tls_could_read(void) | |
3284 | { | |
a5ffa9b4 | 3285 | return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(server_ssl) > 0; |
925ac8e4 JH |
3286 | } |
3287 | ||
059ec3d9 PH |
3288 | |
3289 | /************************************************* | |
3290 | * Read bytes from TLS channel * | |
3291 | *************************************************/ | |
3292 | ||
3293 | /* | |
3294 | Arguments: | |
74f1a423 | 3295 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
3296 | buff buffer of data |
3297 | len size of buffer | |
3298 | ||
3299 | Returns: the number of bytes read | |
afdb5e9c | 3300 | -1 after a failed read, including EOF |
817d9f57 JH |
3301 | |
3302 | Only used by the client-side TLS. | |
059ec3d9 PH |
3303 | */ |
3304 | ||
3305 | int | |
74f1a423 | 3306 | tls_read(void * ct_ctx, uschar *buff, size_t len) |
059ec3d9 | 3307 | { |
74f1a423 | 3308 | SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; |
059ec3d9 PH |
3309 | int inbytes; |
3310 | int error; | |
3311 | ||
389ca47a | 3312 | DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, |
c80c5570 | 3313 | buff, (unsigned int)len); |
059ec3d9 | 3314 | |
389ca47a JH |
3315 | inbytes = SSL_read(ssl, CS buff, len); |
3316 | error = SSL_get_error(ssl, inbytes); | |
059ec3d9 PH |
3317 | |
3318 | if (error == SSL_ERROR_ZERO_RETURN) | |
3319 | { | |
3320 | DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n"); | |
3321 | return -1; | |
3322 | } | |
3323 | else if (error != SSL_ERROR_NONE) | |
059ec3d9 | 3324 | return -1; |
059ec3d9 PH |
3325 | |
3326 | return inbytes; | |
3327 | } | |
3328 | ||
3329 | ||
3330 | ||
3331 | ||
3332 | ||
3333 | /************************************************* | |
3334 | * Write bytes down TLS channel * | |
3335 | *************************************************/ | |
3336 | ||
3337 | /* | |
3338 | Arguments: | |
74f1a423 | 3339 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
3340 | buff buffer of data |
3341 | len number of bytes | |
925ac8e4 | 3342 | more further data expected soon |
059ec3d9 PH |
3343 | |
3344 | Returns: the number of bytes after a successful write, | |
3345 | -1 after a failed write | |
817d9f57 JH |
3346 | |
3347 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
3348 | */ |
3349 | ||
3350 | int | |
74f1a423 | 3351 | tls_write(void * ct_ctx, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 3352 | { |
ac35befe | 3353 | size_t olen = len; |
d7978c0f | 3354 | int outbytes, error; |
c09dbcfb JH |
3355 | SSL * ssl = ct_ctx |
3356 | ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl; | |
3357 | static gstring * server_corked = NULL; | |
3358 | gstring ** corkedp = ct_ctx | |
3359 | ? &((exim_openssl_client_tls_ctx *)ct_ctx)->corked : &server_corked; | |
3360 | gstring * corked = *corkedp; | |
a5ffa9b4 | 3361 | |
ef698bf6 | 3362 | DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__, |
b93be52e | 3363 | buff, (unsigned long)len, more ? ", more" : ""); |
a5ffa9b4 JH |
3364 | |
3365 | /* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when | |
3366 | "more" is notified. This hack is only ok if small amounts are involved AND only | |
3367 | one stream does it, in one context (i.e. no store reset). Currently it is used | |
c09dbcfb JH |
3368 | for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. |
3369 | We support callouts done by the server process by using a separate client | |
3370 | context for the stashed information. */ | |
ac35befe JH |
3371 | /* + if PIPE_COMMAND, banner & ehlo-resp for smmtp-on-connect. Suspect there's |
3372 | a store reset there, so use POOL_PERM. */ | |
3373 | /* + if CHUNKING, cmds EHLO,MAIL,RCPT(s),BDAT */ | |
a5ffa9b4 | 3374 | |
ac35befe | 3375 | if ((more || corked)) |
a5ffa9b4 | 3376 | { |
4e48d56c | 3377 | #ifdef SUPPORT_PIPE_CONNECT |
ee8b8090 JH |
3378 | int save_pool = store_pool; |
3379 | store_pool = POOL_PERM; | |
3380 | #endif | |
3381 | ||
acec9514 | 3382 | corked = string_catn(corked, buff, len); |
ee8b8090 | 3383 | |
4e48d56c | 3384 | #ifdef SUPPORT_PIPE_CONNECT |
ee8b8090 JH |
3385 | store_pool = save_pool; |
3386 | #endif | |
3387 | ||
a5ffa9b4 | 3388 | if (more) |
c09dbcfb JH |
3389 | { |
3390 | *corkedp = corked; | |
a5ffa9b4 | 3391 | return len; |
c09dbcfb | 3392 | } |
acec9514 JH |
3393 | buff = CUS corked->s; |
3394 | len = corked->ptr; | |
c09dbcfb | 3395 | *corkedp = NULL; |
a5ffa9b4 | 3396 | } |
059ec3d9 | 3397 | |
d7978c0f | 3398 | for (int left = len; left > 0;) |
059ec3d9 | 3399 | { |
74f1a423 | 3400 | DEBUG(D_tls) debug_printf("SSL_write(%p, %p, %d)\n", ssl, buff, left); |
059ec3d9 PH |
3401 | outbytes = SSL_write(ssl, CS buff, left); |
3402 | error = SSL_get_error(ssl, outbytes); | |
3403 | DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); | |
3404 | switch (error) | |
3405 | { | |
3406 | case SSL_ERROR_SSL: | |
0abc5a13 | 3407 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
96f5fe4c JH |
3408 | log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring); |
3409 | return -1; | |
059ec3d9 PH |
3410 | |
3411 | case SSL_ERROR_NONE: | |
96f5fe4c JH |
3412 | left -= outbytes; |
3413 | buff += outbytes; | |
3414 | break; | |
059ec3d9 PH |
3415 | |
3416 | case SSL_ERROR_ZERO_RETURN: | |
96f5fe4c JH |
3417 | log_write(0, LOG_MAIN, "SSL channel closed on write"); |
3418 | return -1; | |
059ec3d9 | 3419 | |
817d9f57 | 3420 | case SSL_ERROR_SYSCALL: |
96f5fe4c JH |
3421 | log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", |
3422 | sender_fullhost ? sender_fullhost : US"<unknown>", | |
3423 | strerror(errno)); | |
3424 | return -1; | |
817d9f57 | 3425 | |
059ec3d9 | 3426 | default: |
96f5fe4c JH |
3427 | log_write(0, LOG_MAIN, "SSL_write error %d", error); |
3428 | return -1; | |
059ec3d9 PH |
3429 | } |
3430 | } | |
ac35befe | 3431 | return olen; |
059ec3d9 PH |
3432 | } |
3433 | ||
3434 | ||
3435 | ||
3436 | /************************************************* | |
3437 | * Close down a TLS session * | |
3438 | *************************************************/ | |
3439 | ||
3440 | /* This is also called from within a delivery subprocess forked from the | |
3441 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
3442 | would tamper with the SSL session in the parent process). | |
3443 | ||
dec766a1 | 3444 | Arguments: |
74f1a423 | 3445 | ct_ctx client TLS context pointer, or NULL for the one global server context |
dec766a1 WB |
3446 | shutdown 1 if TLS close-alert is to be sent, |
3447 | 2 if also response to be waited for | |
3448 | ||
059ec3d9 | 3449 | Returns: nothing |
817d9f57 JH |
3450 | |
3451 | Used by both server-side and client-side TLS. | |
059ec3d9 PH |
3452 | */ |
3453 | ||
3454 | void | |
74f1a423 | 3455 | tls_close(void * ct_ctx, int shutdown) |
059ec3d9 | 3456 | { |
74f1a423 JH |
3457 | exim_openssl_client_tls_ctx * o_ctx = ct_ctx; |
3458 | SSL_CTX **ctxp = o_ctx ? &o_ctx->ctx : &server_ctx; | |
3459 | SSL **sslp = o_ctx ? &o_ctx->ssl : &server_ssl; | |
3460 | int *fdp = o_ctx ? &tls_out.active.sock : &tls_in.active.sock; | |
817d9f57 JH |
3461 | |
3462 | if (*fdp < 0) return; /* TLS was not active */ | |
059ec3d9 PH |
3463 | |
3464 | if (shutdown) | |
3465 | { | |
dec766a1 WB |
3466 | int rc; |
3467 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", | |
3468 | shutdown > 1 ? " (with response-wait)" : ""); | |
3469 | ||
3470 | if ( (rc = SSL_shutdown(*sslp)) == 0 /* send "close notify" alert */ | |
3471 | && shutdown > 1) | |
3472 | { | |
c2a1bba0 | 3473 | ALARM(2); |
dec766a1 | 3474 | rc = SSL_shutdown(*sslp); /* wait for response */ |
c2a1bba0 | 3475 | ALARM_CLR(0); |
dec766a1 WB |
3476 | } |
3477 | ||
3478 | if (rc < 0) DEBUG(D_tls) | |
3479 | { | |
0abc5a13 | 3480 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
dec766a1 WB |
3481 | debug_printf("SSL_shutdown: %s\n", ssl_errstring); |
3482 | } | |
3483 | } | |
3484 | ||
74f1a423 | 3485 | if (!o_ctx) /* server side */ |
dec766a1 | 3486 | { |
bd231acd | 3487 | #ifndef DISABLE_OCSP |
dec766a1 | 3488 | sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free); |
dec766a1 | 3489 | server_static_cbinfo->verify_stack = NULL; |
37f0ce65 | 3490 | #endif |
059ec3d9 | 3491 | |
bd231acd JH |
3492 | receive_getc = smtp_getc; |
3493 | receive_getbuf = smtp_getbuf; | |
3494 | receive_get_cache = smtp_get_cache; | |
3495 | receive_ungetc = smtp_ungetc; | |
3496 | receive_feof = smtp_feof; | |
3497 | receive_ferror = smtp_ferror; | |
3498 | receive_smtp_buffered = smtp_buffered; | |
3499 | tls_in.active.tls_ctx = NULL; | |
3500 | tls_in.sni = NULL; | |
3501 | /* Leave bits, peercert, cipher, peerdn, certificate_verified set, for logging */ | |
3502 | } | |
3503 | ||
dec766a1 | 3504 | SSL_CTX_free(*ctxp); |
817d9f57 | 3505 | SSL_free(*sslp); |
dec766a1 | 3506 | *ctxp = NULL; |
817d9f57 | 3507 | *sslp = NULL; |
817d9f57 | 3508 | *fdp = -1; |
059ec3d9 PH |
3509 | } |
3510 | ||
36f12725 NM |
3511 | |
3512 | ||
3513 | ||
3375e053 PP |
3514 | /************************************************* |
3515 | * Let tls_require_ciphers be checked at startup * | |
3516 | *************************************************/ | |
3517 | ||
3518 | /* The tls_require_ciphers option, if set, must be something which the | |
3519 | library can parse. | |
3520 | ||
3521 | Returns: NULL on success, or error message | |
3522 | */ | |
3523 | ||
3524 | uschar * | |
3525 | tls_validate_require_cipher(void) | |
3526 | { | |
3527 | SSL_CTX *ctx; | |
3528 | uschar *s, *expciphers, *err; | |
3529 | ||
3530 | /* this duplicates from tls_init(), we need a better "init just global | |
3531 | state, for no specific purpose" singleton function of our own */ | |
3532 | ||
7434882d | 3533 | #ifdef EXIM_NEED_OPENSSL_INIT |
3375e053 PP |
3534 | SSL_load_error_strings(); |
3535 | OpenSSL_add_ssl_algorithms(); | |
7434882d | 3536 | #endif |
3375e053 PP |
3537 | #if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256) |
3538 | /* SHA256 is becoming ever more popular. This makes sure it gets added to the | |
3539 | list of available digests. */ | |
3540 | EVP_add_digest(EVP_sha256()); | |
3541 | #endif | |
3542 | ||
3543 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
3544 | return NULL; | |
3545 | ||
cf0c6164 JH |
3546 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
3547 | &err)) | |
3375e053 PP |
3548 | return US"failed to expand tls_require_ciphers"; |
3549 | ||
3550 | if (!(expciphers && *expciphers)) | |
3551 | return NULL; | |
3552 | ||
3553 | /* normalisation ripped from above */ | |
3554 | s = expciphers; | |
3555 | while (*s != 0) { if (*s == '_') *s = '-'; s++; } | |
3556 | ||
3557 | err = NULL; | |
3558 | ||
7a8b9519 JH |
3559 | #ifdef EXIM_HAVE_OPENSSL_TLS_METHOD |
3560 | if (!(ctx = SSL_CTX_new(TLS_server_method()))) | |
3561 | #else | |
3562 | if (!(ctx = SSL_CTX_new(SSLv23_server_method()))) | |
3563 | #endif | |
3375e053 | 3564 | { |
0abc5a13 | 3565 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
3375e053 PP |
3566 | return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring); |
3567 | } | |
3568 | ||
3569 | DEBUG(D_tls) | |
3570 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
3571 | ||
3572 | if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) | |
3573 | { | |
0abc5a13 | 3574 | ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); |
cf0c6164 JH |
3575 | err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s", |
3576 | expciphers, ssl_errstring); | |
3375e053 PP |
3577 | } |
3578 | ||
3579 | SSL_CTX_free(ctx); | |
3580 | ||
3581 | return err; | |
3582 | } | |
3583 | ||
3584 | ||
3585 | ||
3586 | ||
36f12725 NM |
3587 | /************************************************* |
3588 | * Report the library versions. * | |
3589 | *************************************************/ | |
3590 | ||
3591 | /* There have historically been some issues with binary compatibility in | |
3592 | OpenSSL libraries; if Exim (like many other applications) is built against | |
3593 | one version of OpenSSL but the run-time linker picks up another version, | |
3594 | it can result in serious failures, including crashing with a SIGSEGV. So | |
3595 | report the version found by the compiler and the run-time version. | |
3596 | ||
f64a1e23 PP |
3597 | Note: some OS vendors backport security fixes without changing the version |
3598 | number/string, and the version date remains unchanged. The _build_ date | |
3599 | will change, so we can more usefully assist with version diagnosis by also | |
3600 | reporting the build date. | |
3601 | ||
36f12725 NM |
3602 | Arguments: a FILE* to print the results to |
3603 | Returns: nothing | |
3604 | */ | |
3605 | ||
3606 | void | |
3607 | tls_version_report(FILE *f) | |
3608 | { | |
754a0503 | 3609 | fprintf(f, "Library version: OpenSSL: Compile: %s\n" |
f64a1e23 PP |
3610 | " Runtime: %s\n" |
3611 | " : %s\n", | |
754a0503 | 3612 | OPENSSL_VERSION_TEXT, |
f64a1e23 PP |
3613 | SSLeay_version(SSLEAY_VERSION), |
3614 | SSLeay_version(SSLEAY_BUILT_ON)); | |
3615 | /* third line is 38 characters for the %s and the line is 73 chars long; | |
3616 | the OpenSSL output includes a "built on: " prefix already. */ | |
36f12725 NM |
3617 | } |
3618 | ||
9e3331ea TK |
3619 | |
3620 | ||
3621 | ||
3622 | /************************************************* | |
17c76198 | 3623 | * Random number generation * |
9e3331ea TK |
3624 | *************************************************/ |
3625 | ||
3626 | /* Pseudo-random number generation. The result is not expected to be | |
3627 | cryptographically strong but not so weak that someone will shoot themselves | |
3628 | in the foot using it as a nonce in input in some email header scheme or | |
3629 | whatever weirdness they'll twist this into. The result should handle fork() | |
3630 | and avoid repeating sequences. OpenSSL handles that for us. | |
3631 | ||
3632 | Arguments: | |
3633 | max range maximum | |
3634 | Returns a random number in range [0, max-1] | |
3635 | */ | |
3636 | ||
3637 | int | |
17c76198 | 3638 | vaguely_random_number(int max) |
9e3331ea TK |
3639 | { |
3640 | unsigned int r; | |
3641 | int i, needed_len; | |
de6135a0 PP |
3642 | static pid_t pidlast = 0; |
3643 | pid_t pidnow; | |
9e3331ea TK |
3644 | uschar smallbuf[sizeof(r)]; |
3645 | ||
3646 | if (max <= 1) | |
3647 | return 0; | |
3648 | ||
de6135a0 PP |
3649 | pidnow = getpid(); |
3650 | if (pidnow != pidlast) | |
3651 | { | |
3652 | /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state | |
3653 | is unique for each thread", this doesn't apparently apply across processes, | |
3654 | so our own warning from vaguely_random_number_fallback() applies here too. | |
3655 | Fix per PostgreSQL. */ | |
3656 | if (pidlast != 0) | |
3657 | RAND_cleanup(); | |
3658 | pidlast = pidnow; | |
3659 | } | |
3660 | ||
9e3331ea TK |
3661 | /* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */ |
3662 | if (!RAND_status()) | |
3663 | { | |
3664 | randstuff r; | |
3665 | gettimeofday(&r.tv, NULL); | |
3666 | r.p = getpid(); | |
3667 | ||
5903c6ff | 3668 | RAND_seed(US (&r), sizeof(r)); |
9e3331ea TK |
3669 | } |
3670 | /* We're after pseudo-random, not random; if we still don't have enough data | |
3671 | in the internal PRNG then our options are limited. We could sleep and hope | |
3672 | for entropy to come along (prayer technique) but if the system is so depleted | |
3673 | in the first place then something is likely to just keep taking it. Instead, | |
3674 | we'll just take whatever little bit of pseudo-random we can still manage to | |
3675 | get. */ | |
3676 | ||
3677 | needed_len = sizeof(r); | |
3678 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
3679 | asked for a number less than 10. */ | |
3680 | for (r = max, i = 0; r; ++i) | |
3681 | r >>= 1; | |
3682 | i = (i + 7) / 8; | |
3683 | if (i < needed_len) | |
3684 | needed_len = i; | |
3685 | ||
c8dfb21d | 3686 | #ifdef EXIM_HAVE_RAND_PSEUDO |
9e3331ea | 3687 | /* We do not care if crypto-strong */ |
17c76198 | 3688 | i = RAND_pseudo_bytes(smallbuf, needed_len); |
c8dfb21d JH |
3689 | #else |
3690 | i = RAND_bytes(smallbuf, needed_len); | |
3691 | #endif | |
3692 | ||
17c76198 PP |
3693 | if (i < 0) |
3694 | { | |
3695 | DEBUG(D_all) | |
3696 | debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); | |
3697 | return vaguely_random_number_fallback(max); | |
3698 | } | |
3699 | ||
9e3331ea | 3700 | r = 0; |
d7978c0f JH |
3701 | for (uschar * p = smallbuf; needed_len; --needed_len, ++p) |
3702 | r = 256 * r + *p; | |
9e3331ea TK |
3703 | |
3704 | /* We don't particularly care about weighted results; if someone wants | |
3705 | smooth distribution and cares enough then they should submit a patch then. */ | |
3706 | return r % max; | |
3707 | } | |
3708 | ||
77bb000f PP |
3709 | |
3710 | ||
3711 | ||
3712 | /************************************************* | |
3713 | * OpenSSL option parse * | |
3714 | *************************************************/ | |
3715 | ||
3716 | /* Parse one option for tls_openssl_options_parse below | |
3717 | ||
3718 | Arguments: | |
3719 | name one option name | |
3720 | value place to store a value for it | |
3721 | Returns success or failure in parsing | |
3722 | */ | |
3723 | ||
77bb000f | 3724 | |
c80c5570 | 3725 | |
77bb000f PP |
3726 | static BOOL |
3727 | tls_openssl_one_option_parse(uschar *name, long *value) | |
3728 | { | |
3729 | int first = 0; | |
3730 | int last = exim_openssl_options_size; | |
3731 | while (last > first) | |
3732 | { | |
3733 | int middle = (first + last)/2; | |
3734 | int c = Ustrcmp(name, exim_openssl_options[middle].name); | |
3735 | if (c == 0) | |
3736 | { | |
3737 | *value = exim_openssl_options[middle].value; | |
3738 | return TRUE; | |
3739 | } | |
3740 | else if (c > 0) | |
3741 | first = middle + 1; | |
3742 | else | |
3743 | last = middle; | |
3744 | } | |
3745 | return FALSE; | |
3746 | } | |
3747 | ||
3748 | ||
3749 | ||
3750 | ||
3751 | /************************************************* | |
3752 | * OpenSSL option parsing logic * | |
3753 | *************************************************/ | |
3754 | ||
3755 | /* OpenSSL has a number of compatibility options which an administrator might | |
3756 | reasonably wish to set. Interpret a list similarly to decode_bits(), so that | |
3757 | we look like log_selector. | |
3758 | ||
3759 | Arguments: | |
3760 | option_spec the administrator-supplied string of options | |
3761 | results ptr to long storage for the options bitmap | |
3762 | Returns success or failure | |
3763 | */ | |
3764 | ||
3765 | BOOL | |
3766 | tls_openssl_options_parse(uschar *option_spec, long *results) | |
3767 | { | |
3768 | long result, item; | |
d7978c0f | 3769 | uschar *end; |
77bb000f PP |
3770 | uschar keep_c; |
3771 | BOOL adding, item_parsed; | |
3772 | ||
b10c87b3 | 3773 | /* Server: send no (<= TLS1.2) session tickets */ |
7006ee24 | 3774 | result = SSL_OP_NO_TICKET; |
b10c87b3 | 3775 | |
b1770b6e | 3776 | /* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed |
da3ad30d | 3777 | * from default because it increases BEAST susceptibility. */ |
f0f5a555 PP |
3778 | #ifdef SSL_OP_NO_SSLv2 |
3779 | result |= SSL_OP_NO_SSLv2; | |
3780 | #endif | |
b10c87b3 JH |
3781 | #ifdef SSL_OP_NO_SSLv3 |
3782 | result |= SSL_OP_NO_SSLv3; | |
3783 | #endif | |
a57b6200 JH |
3784 | #ifdef SSL_OP_SINGLE_DH_USE |
3785 | result |= SSL_OP_SINGLE_DH_USE; | |
3786 | #endif | |
77bb000f | 3787 | |
7006ee24 | 3788 | if (!option_spec) |
77bb000f PP |
3789 | { |
3790 | *results = result; | |
3791 | return TRUE; | |
3792 | } | |
3793 | ||
b10c87b3 | 3794 | for (uschar * s = option_spec; *s; /**/) |
77bb000f PP |
3795 | { |
3796 | while (isspace(*s)) ++s; | |
3797 | if (*s == '\0') | |
3798 | break; | |
3799 | if (*s != '+' && *s != '-') | |
3800 | { | |
3801 | DEBUG(D_tls) debug_printf("malformed openssl option setting: " | |
0e944a0d | 3802 | "+ or - expected but found \"%s\"\n", s); |
77bb000f PP |
3803 | return FALSE; |
3804 | } | |
3805 | adding = *s++ == '+'; | |
3806 | for (end = s; (*end != '\0') && !isspace(*end); ++end) /**/ ; | |
3807 | keep_c = *end; | |
3808 | *end = '\0'; | |
3809 | item_parsed = tls_openssl_one_option_parse(s, &item); | |
96f5fe4c | 3810 | *end = keep_c; |
77bb000f PP |
3811 | if (!item_parsed) |
3812 | { | |
0e944a0d | 3813 | DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s); |
77bb000f PP |
3814 | return FALSE; |
3815 | } | |
f97ca6d1 JH |
3816 | DEBUG(D_tls) debug_printf("openssl option, %s %8lx: %lx (%s)\n", |
3817 | adding ? "adding to " : "removing from", result, item, s); | |
77bb000f PP |
3818 | if (adding) |
3819 | result |= item; | |
3820 | else | |
3821 | result &= ~item; | |
77bb000f PP |
3822 | s = end; |
3823 | } | |
3824 | ||
3825 | *results = result; | |
3826 | return TRUE; | |
3827 | } | |
3828 | ||
8442641e | 3829 | #endif /*!MACRO_PREDEF*/ |
9d1c15ef JH |
3830 | /* vi: aw ai sw=2 |
3831 | */ | |
059ec3d9 | 3832 | /* End of tls-openssl.c */ |