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420a0d19 CE |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
5 | /* Copyright (c) University of Cambridge 1995 - 2014 */ | |
6 | /* See the file NOTICE for conditions of use and distribution. */ | |
7 | ||
8 | /* Copyright (c) Phil Pennock 2012 */ | |
9 | ||
10 | /* This file provides TLS/SSL support for Exim using the GnuTLS library, | |
11 | one of the available supported implementations. This file is #included into | |
12 | tls.c when USE_GNUTLS has been set. | |
13 | ||
14 | The code herein is a revamp of GnuTLS integration using the current APIs; the | |
15 | original tls-gnu.c was based on a patch which was contributed by Nikos | |
16 | Mavroyanopoulos. The revamp is partially a rewrite, partially cut&paste as | |
17 | appropriate. | |
18 | ||
19 | APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, | |
20 | which is not widely deployed by OS vendors. Will note issues below, which may | |
21 | assist in updating the code in the future. Another sources of hints is | |
22 | mod_gnutls for Apache (SNI callback registration and handling). | |
23 | ||
24 | Keeping client and server variables more split than before and is currently | |
25 | the norm, in anticipation of TLS in ACL callouts. | |
26 | ||
27 | I wanted to switch to gnutls_certificate_set_verify_function() so that | |
28 | certificate rejection could happen during handshake where it belongs, rather | |
29 | than being dropped afterwards, but that was introduced in 2.10.0 and Debian | |
30 | (6.0.5) is still on 2.8.6. So for now we have to stick with sub-par behaviour. | |
31 | ||
32 | (I wasn't looking for libraries quite that old, when updating to get rid of | |
33 | compiler warnings of deprecated APIs. If it turns out that a lot of the rest | |
34 | require current GnuTLS, then we'll drop support for the ancient libraries). | |
35 | */ | |
36 | ||
37 | #include <gnutls/gnutls.h> | |
38 | /* needed for cert checks in verification and DN extraction: */ | |
39 | #include <gnutls/x509.h> | |
40 | /* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ | |
41 | #include <gnutls/crypto.h> | |
42 | /* needed to disable PKCS11 autoload unless requested */ | |
43 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
44 | # include <gnutls/pkcs11.h> | |
45 | #endif | |
46 | #if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) | |
47 | # warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" | |
48 | # define DISABLE_OCSP | |
49 | #endif | |
50 | ||
51 | #ifndef DISABLE_OCSP | |
52 | # include <gnutls/ocsp.h> | |
53 | #endif | |
54 | ||
55 | /* GnuTLS 2 vs 3 | |
56 | ||
57 | GnuTLS 3 only: | |
58 | gnutls_global_set_audit_log_function() | |
59 | ||
60 | Changes: | |
61 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
62 | */ | |
63 | ||
64 | /* Local static variables for GnuTLS */ | |
65 | ||
66 | /* Values for verify_requirement */ | |
67 | ||
68 | enum peer_verify_requirement | |
69 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED | |
70 | #ifdef EXPERIMENTAL_CERTNAMES | |
71 | ,VERIFY_WITHHOST | |
72 | #endif | |
73 | }; | |
74 | ||
75 | /* This holds most state for server or client; with this, we can set up an | |
76 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
77 | over the TLS variables available for expansion. | |
78 | ||
79 | Some of these correspond to variables in globals.c; those variables will | |
80 | be set to point to content in one of these instances, as appropriate for | |
81 | the stage of the process lifetime. | |
82 | ||
83 | Not handled here: global tls_channelbinding_b64. | |
84 | */ | |
85 | ||
86 | typedef struct exim_gnutls_state { | |
87 | gnutls_session_t session; | |
88 | gnutls_certificate_credentials_t x509_cred; | |
89 | gnutls_priority_t priority_cache; | |
90 | enum peer_verify_requirement verify_requirement; | |
91 | int fd_in; | |
92 | int fd_out; | |
93 | BOOL peer_cert_verified; | |
94 | BOOL trigger_sni_changes; | |
95 | BOOL have_set_peerdn; | |
96 | const struct host_item *host; | |
97 | gnutls_x509_crt_t peercert; | |
98 | uschar *peerdn; | |
99 | uschar *ciphersuite; | |
100 | uschar *received_sni; | |
101 | ||
102 | const uschar *tls_certificate; | |
103 | const uschar *tls_privatekey; | |
104 | const uschar *tls_sni; /* client send only, not received */ | |
105 | const uschar *tls_verify_certificates; | |
106 | const uschar *tls_crl; | |
107 | const uschar *tls_require_ciphers; | |
108 | ||
109 | uschar *exp_tls_certificate; | |
110 | uschar *exp_tls_privatekey; | |
111 | uschar *exp_tls_verify_certificates; | |
112 | uschar *exp_tls_crl; | |
113 | uschar *exp_tls_require_ciphers; | |
114 | uschar *exp_tls_ocsp_file; | |
115 | #ifdef EXPERIMENTAL_CERTNAMES | |
116 | uschar *exp_tls_verify_cert_hostnames; | |
117 | #endif | |
118 | ||
119 | tls_support *tlsp; /* set in tls_init() */ | |
120 | ||
121 | uschar *xfer_buffer; | |
122 | int xfer_buffer_lwm; | |
123 | int xfer_buffer_hwm; | |
124 | int xfer_eof; | |
125 | int xfer_error; | |
126 | } exim_gnutls_state_st; | |
127 | ||
128 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
129 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, | |
130 | NULL, NULL, NULL, NULL, | |
131 | NULL, NULL, NULL, NULL, NULL, NULL, | |
132 | NULL, NULL, NULL, NULL, NULL, NULL, NULL, | |
133 | #ifdef EXPERIMENTAL_CERTNAMES | |
134 | NULL, | |
135 | #endif | |
136 | NULL, | |
137 | NULL, 0, 0, 0, 0, | |
138 | }; | |
139 | ||
140 | /* Not only do we have our own APIs which don't pass around state, assuming | |
141 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
142 | for callbacks, or as part of the session, so we have to keep a "this is the | |
143 | context we're currently dealing with" pointer and rely upon being | |
144 | single-threaded to keep from processing data on an inbound TLS connection while | |
145 | talking to another TLS connection for an outbound check. This does mean that | |
146 | there's no way for heart-beats to be responded to, for the duration of the | |
147 | second connection. */ | |
148 | ||
149 | static exim_gnutls_state_st state_server, state_client; | |
150 | ||
151 | /* dh_params are initialised once within the lifetime of a process using TLS; | |
152 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
153 | don't want to repeat this. */ | |
154 | ||
155 | static gnutls_dh_params_t dh_server_params = NULL; | |
156 | ||
157 | /* No idea how this value was chosen; preserving it. Default is 3600. */ | |
158 | ||
159 | static const int ssl_session_timeout = 200; | |
160 | ||
161 | static const char * const exim_default_gnutls_priority = "NORMAL"; | |
162 | ||
163 | /* Guard library core initialisation */ | |
164 | ||
165 | static BOOL exim_gnutls_base_init_done = FALSE; | |
166 | ||
167 | ||
168 | /* ------------------------------------------------------------------------ */ | |
169 | /* macros */ | |
170 | ||
171 | #define MAX_HOST_LEN 255 | |
172 | ||
173 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup | |
174 | the library logging; a value less than 0 disables the calls to set up logging | |
175 | callbacks. */ | |
176 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL | |
177 | #define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 | |
178 | #endif | |
179 | ||
180 | #ifndef EXIM_CLIENT_DH_MIN_BITS | |
181 | #define EXIM_CLIENT_DH_MIN_BITS 1024 | |
182 | #endif | |
183 | ||
184 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we | |
185 | can ask for a bit-strength. Without that, we stick to the constant we had | |
186 | before, for now. */ | |
187 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 | |
188 | #define EXIM_SERVER_DH_BITS_PRE2_12 1024 | |
189 | #endif | |
190 | ||
191 | #define exim_gnutls_err_check(Label) do { \ | |
192 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
193 | ||
194 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) | |
195 | ||
196 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
197 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
198 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
199 | # define HAVE_GNUTLS_RND | |
200 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option | |
201 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
202 | * isn't available sometimes, so this needs to become a conditional | |
203 | * compilation; the sanest way to deal with this being a problem on | |
204 | * older OSes is to block it in the Local/Makefile with this compiler | |
205 | * definition */ | |
206 | # ifndef AVOID_GNUTLS_PKCS11 | |
207 | # define HAVE_GNUTLS_PKCS11 | |
208 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
209 | #endif | |
210 | ||
211 | ||
212 | ||
213 | ||
214 | /* ------------------------------------------------------------------------ */ | |
215 | /* Callback declarations */ | |
216 | ||
217 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
218 | static void exim_gnutls_logger_cb(int level, const char *message); | |
219 | #endif | |
220 | ||
221 | static int exim_sni_handling_cb(gnutls_session_t session); | |
222 | ||
223 | #ifndef DISABLE_OCSP | |
224 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
225 | gnutls_datum_t * ocsp_response); | |
226 | #endif | |
227 | ||
228 | ||
229 | ||
230 | /* ------------------------------------------------------------------------ */ | |
231 | /* Static functions */ | |
232 | ||
233 | /************************************************* | |
234 | * Handle TLS error * | |
235 | *************************************************/ | |
236 | ||
237 | /* Called from lots of places when errors occur before actually starting to do | |
238 | the TLS handshake, that is, while the session is still in clear. Always returns | |
239 | DEFER for a server and FAIL for a client so that most calls can use "return | |
240 | tls_error(...)" to do this processing and then give an appropriate return. A | |
241 | single function is used for both server and client, because it is called from | |
242 | some shared functions. | |
243 | ||
244 | Argument: | |
245 | prefix text to include in the logged error | |
246 | msg additional error string (may be NULL) | |
247 | usually obtained from gnutls_strerror() | |
248 | host NULL if setting up a server; | |
249 | the connected host if setting up a client | |
250 | ||
251 | Returns: OK/DEFER/FAIL | |
252 | */ | |
253 | ||
254 | static int | |
255 | tls_error(const uschar *prefix, const char *msg, const host_item *host) | |
256 | { | |
257 | if (host) | |
258 | { | |
259 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", | |
260 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); | |
261 | return FAIL; | |
262 | } | |
263 | else | |
264 | { | |
265 | uschar *conn_info = smtp_get_connection_info(); | |
266 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) | |
267 | conn_info += 5; | |
268 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", | |
269 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); | |
270 | return DEFER; | |
271 | } | |
272 | } | |
273 | ||
274 | ||
275 | ||
276 | ||
277 | /************************************************* | |
278 | * Deal with logging errors during I/O * | |
279 | *************************************************/ | |
280 | ||
281 | /* We have to get the identity of the peer from saved data. | |
282 | ||
283 | Argument: | |
284 | state the current GnuTLS exim state container | |
285 | rc the GnuTLS error code, or 0 if it's a local error | |
286 | when text identifying read or write | |
287 | text local error text when ec is 0 | |
288 | ||
289 | Returns: nothing | |
290 | */ | |
291 | ||
292 | static void | |
293 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
294 | { | |
295 | const char *msg; | |
296 | ||
297 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) | |
298 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
299 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
300 | else | |
301 | msg = gnutls_strerror(rc); | |
302 | ||
303 | tls_error(when, msg, state->host); | |
304 | } | |
305 | ||
306 | ||
307 | ||
308 | ||
309 | /************************************************* | |
310 | * Set various Exim expansion vars * | |
311 | *************************************************/ | |
312 | ||
313 | #define exim_gnutls_cert_err(Label) \ | |
314 | do \ | |
315 | { \ | |
316 | if (rc != GNUTLS_E_SUCCESS) \ | |
317 | { \ | |
318 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
319 | (Label), gnutls_strerror(rc)); \ | |
320 | return rc; \ | |
321 | } \ | |
322 | } while (0) | |
323 | ||
324 | static int | |
325 | import_cert(const gnutls_datum * cert, gnutls_x509_crt_t * crtp) | |
326 | { | |
327 | int rc; | |
328 | ||
329 | rc = gnutls_x509_crt_init(crtp); | |
330 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
331 | ||
332 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
333 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
334 | ||
335 | return rc; | |
336 | } | |
337 | ||
338 | #undef exim_gnutls_cert_err | |
339 | ||
340 | ||
341 | /* We set various Exim global variables from the state, once a session has | |
342 | been established. With TLS callouts, may need to change this to stack | |
343 | variables, or just re-call it with the server state after client callout | |
344 | has finished. | |
345 | ||
346 | Make sure anything set here is unset in tls_getc(). | |
347 | ||
348 | Sets: | |
349 | tls_active fd | |
350 | tls_bits strength indicator | |
351 | tls_certificate_verified bool indicator | |
352 | tls_channelbinding_b64 for some SASL mechanisms | |
353 | tls_cipher a string | |
354 | tls_peercert pointer to library internal | |
355 | tls_peerdn a string | |
356 | tls_sni a (UTF-8) string | |
357 | tls_ourcert pointer to library internal | |
358 | ||
359 | Argument: | |
360 | state the relevant exim_gnutls_state_st * | |
361 | */ | |
362 | ||
363 | static void | |
364 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) | |
365 | { | |
366 | gnutls_cipher_algorithm_t cipher; | |
367 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
368 | int old_pool; | |
369 | int rc; | |
370 | gnutls_datum_t channel; | |
371 | #endif | |
372 | tls_support * tlsp = state->tlsp; | |
373 | ||
374 | tlsp->active = state->fd_out; | |
375 | ||
376 | cipher = gnutls_cipher_get(state->session); | |
377 | /* returns size in "bytes" */ | |
378 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; | |
379 | ||
380 | tlsp->cipher = state->ciphersuite; | |
381 | ||
382 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); | |
383 | ||
384 | tlsp->certificate_verified = state->peer_cert_verified; | |
385 | ||
386 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's | |
387 | only available for use for authenticators while this TLS session is running. */ | |
388 | ||
389 | tls_channelbinding_b64 = NULL; | |
390 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
391 | channel.data = NULL; | |
392 | channel.size = 0; | |
393 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
394 | if (rc) { | |
395 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
396 | } else { | |
397 | old_pool = store_pool; | |
398 | store_pool = POOL_PERM; | |
399 | tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); | |
400 | store_pool = old_pool; | |
401 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
402 | } | |
403 | #endif | |
404 | ||
405 | /* peercert is set in peer_status() */ | |
406 | tlsp->peerdn = state->peerdn; | |
407 | tlsp->sni = state->received_sni; | |
408 | ||
409 | /* record our certificate */ | |
410 | { | |
411 | const gnutls_datum * cert = gnutls_certificate_get_ours(state->session); | |
412 | gnutls_x509_crt_t crt; | |
413 | ||
414 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
415 | } | |
416 | } | |
417 | ||
418 | ||
419 | ||
420 | ||
421 | /************************************************* | |
422 | * Setup up DH parameters * | |
423 | *************************************************/ | |
424 | ||
425 | /* Generating the D-H parameters may take a long time. They only need to | |
426 | be re-generated every so often, depending on security policy. What we do is to | |
427 | keep these parameters in a file in the spool directory. If the file does not | |
428 | exist, we generate them. This means that it is easy to cause a regeneration. | |
429 | ||
430 | The new file is written as a temporary file and renamed, so that an incomplete | |
431 | file is never present. If two processes both compute some new parameters, you | |
432 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
433 | prevent this. | |
434 | ||
435 | Returns: OK/DEFER/FAIL | |
436 | */ | |
437 | ||
438 | static int | |
439 | init_server_dh(void) | |
440 | { | |
441 | int fd, rc; | |
442 | unsigned int dh_bits; | |
443 | gnutls_datum m; | |
444 | uschar filename_buf[PATH_MAX]; | |
445 | uschar *filename = NULL; | |
446 | size_t sz; | |
447 | uschar *exp_tls_dhparam; | |
448 | BOOL use_file_in_spool = FALSE; | |
449 | BOOL use_fixed_file = FALSE; | |
450 | host_item *host = NULL; /* dummy for macros */ | |
451 | ||
452 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); | |
453 | ||
454 | rc = gnutls_dh_params_init(&dh_server_params); | |
455 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
456 | ||
457 | m.data = NULL; | |
458 | m.size = 0; | |
459 | ||
460 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
461 | return DEFER; | |
462 | ||
463 | if (!exp_tls_dhparam) | |
464 | { | |
465 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
466 | m.data = US std_dh_prime_default(); | |
467 | m.size = Ustrlen(m.data); | |
468 | } | |
469 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
470 | use_file_in_spool = TRUE; | |
471 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
472 | { | |
473 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
474 | return OK; | |
475 | } | |
476 | else if (exp_tls_dhparam[0] != '/') | |
477 | { | |
478 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
479 | if (m.data == NULL) | |
480 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
481 | m.size = Ustrlen(m.data); | |
482 | } | |
483 | else | |
484 | { | |
485 | use_fixed_file = TRUE; | |
486 | filename = exp_tls_dhparam; | |
487 | } | |
488 | ||
489 | if (m.data) | |
490 | { | |
491 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
492 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
493 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
494 | return OK; | |
495 | } | |
496 | ||
497 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
498 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
499 | different filename and ensure we have sufficient bits. */ | |
500 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
501 | if (!dh_bits) | |
502 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
503 | DEBUG(D_tls) | |
504 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", | |
505 | dh_bits); | |
506 | #else | |
507 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
508 | DEBUG(D_tls) | |
509 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
510 | dh_bits); | |
511 | #endif | |
512 | ||
513 | /* Some clients have hard-coded limits. */ | |
514 | if (dh_bits > tls_dh_max_bits) | |
515 | { | |
516 | DEBUG(D_tls) | |
517 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
518 | tls_dh_max_bits); | |
519 | dh_bits = tls_dh_max_bits; | |
520 | } | |
521 | ||
522 | if (use_file_in_spool) | |
523 | { | |
524 | if (!string_format(filename_buf, sizeof(filename_buf), | |
525 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
526 | return tls_error(US"overlong filename", NULL, NULL); | |
527 | filename = filename_buf; | |
528 | } | |
529 | ||
530 | /* Open the cache file for reading and if successful, read it and set up the | |
531 | parameters. */ | |
532 | ||
533 | fd = Uopen(filename, O_RDONLY, 0); | |
534 | if (fd >= 0) | |
535 | { | |
536 | struct stat statbuf; | |
537 | FILE *fp; | |
538 | int saved_errno; | |
539 | ||
540 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
541 | { | |
542 | saved_errno = errno; | |
543 | (void)close(fd); | |
544 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
545 | } | |
546 | if (!S_ISREG(statbuf.st_mode)) | |
547 | { | |
548 | (void)close(fd); | |
549 | return tls_error(US"TLS cache not a file", NULL, NULL); | |
550 | } | |
551 | fp = fdopen(fd, "rb"); | |
552 | if (!fp) | |
553 | { | |
554 | saved_errno = errno; | |
555 | (void)close(fd); | |
556 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
557 | strerror(saved_errno), NULL); | |
558 | } | |
559 | ||
560 | m.size = statbuf.st_size; | |
561 | m.data = malloc(m.size); | |
562 | if (m.data == NULL) | |
563 | { | |
564 | fclose(fp); | |
565 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
566 | } | |
567 | sz = fread(m.data, m.size, 1, fp); | |
568 | if (!sz) | |
569 | { | |
570 | saved_errno = errno; | |
571 | fclose(fp); | |
572 | free(m.data); | |
573 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
574 | } | |
575 | fclose(fp); | |
576 | ||
577 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
578 | free(m.data); | |
579 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
580 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
581 | } | |
582 | ||
583 | /* If the file does not exist, fall through to compute new data and cache it. | |
584 | If there was any other opening error, it is serious. */ | |
585 | ||
586 | else if (errno == ENOENT) | |
587 | { | |
588 | rc = -1; | |
589 | DEBUG(D_tls) | |
590 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); | |
591 | } | |
592 | else | |
593 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), | |
594 | NULL, NULL); | |
595 | ||
596 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
597 | is not useful. One particular case of this is when upgrading from an older | |
598 | release of Exim in which the data was stored in a different format. We don't | |
599 | try to be clever and support both formats; we just regenerate new data in this | |
600 | case. */ | |
601 | ||
602 | if (rc < 0) | |
603 | { | |
604 | uschar *temp_fn; | |
605 | unsigned int dh_bits_gen = dh_bits; | |
606 | ||
607 | if ((PATH_MAX - Ustrlen(filename)) < 10) | |
608 | return tls_error(US"Filename too long to generate replacement", | |
609 | CS filename, NULL); | |
610 | ||
611 | temp_fn = string_copy(US "%s.XXXXXXX"); | |
612 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
613 | if (fd < 0) | |
614 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); | |
615 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ | |
616 | ||
617 | /* GnuTLS overshoots! | |
618 | * If we ask for 2236, we might get 2237 or more. | |
619 | * But there's no way to ask GnuTLS how many bits there really are. | |
620 | * We can ask how many bits were used in a TLS session, but that's it! | |
621 | * The prime itself is hidden behind too much abstraction. | |
622 | * So we ask for less, and proceed on a wing and a prayer. | |
623 | * First attempt, subtracted 3 for 2233 and got 2240. | |
624 | */ | |
625 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) | |
626 | { | |
627 | dh_bits_gen = dh_bits - 10; | |
628 | DEBUG(D_tls) | |
629 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
630 | dh_bits_gen); | |
631 | } | |
632 | ||
633 | DEBUG(D_tls) | |
634 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
635 | dh_bits_gen); | |
636 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
637 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); | |
638 | ||
639 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
640 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
641 | sample apps handle this. */ | |
642 | ||
643 | sz = 0; | |
644 | m.data = NULL; | |
645 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
646 | m.data, &sz); | |
647 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
648 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
649 | m.size = sz; | |
650 | m.data = malloc(m.size); | |
651 | if (m.data == NULL) | |
652 | return tls_error(US"memory allocation failed", strerror(errno), NULL); | |
653 | /* this will return a size 1 less than the allocation size above */ | |
654 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
655 | m.data, &sz); | |
656 | if (rc != GNUTLS_E_SUCCESS) | |
657 | { | |
658 | free(m.data); | |
659 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
660 | } | |
661 | m.size = sz; /* shrink by 1, probably */ | |
662 | ||
663 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); | |
664 | if (sz != m.size) | |
665 | { | |
666 | free(m.data); | |
667 | return tls_error(US"TLS cache write D-H params failed", | |
668 | strerror(errno), NULL); | |
669 | } | |
670 | free(m.data); | |
671 | sz = write_to_fd_buf(fd, US"\n", 1); | |
672 | if (sz != 1) | |
673 | return tls_error(US"TLS cache write D-H params final newline failed", | |
674 | strerror(errno), NULL); | |
675 | ||
676 | rc = close(fd); | |
677 | if (rc) | |
678 | return tls_error(US"TLS cache write close() failed", | |
679 | strerror(errno), NULL); | |
680 | ||
681 | if (Urename(temp_fn, filename) < 0) | |
682 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
683 | temp_fn, filename), strerror(errno), NULL); | |
684 | ||
685 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); | |
686 | } | |
687 | ||
688 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); | |
689 | return OK; | |
690 | } | |
691 | ||
692 | ||
693 | ||
694 | ||
695 | /************************************************* | |
696 | * Variables re-expanded post-SNI * | |
697 | *************************************************/ | |
698 | ||
699 | /* Called from both server and client code, via tls_init(), and also from | |
700 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
701 | ||
702 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
703 | ||
704 | The callback should not call us unless state->trigger_sni_changes is true, | |
705 | which we are responsible for setting on the first pass through. | |
706 | ||
707 | Arguments: | |
708 | state exim_gnutls_state_st * | |
709 | ||
710 | Returns: OK/DEFER/FAIL | |
711 | */ | |
712 | ||
713 | static int | |
714 | tls_expand_session_files(exim_gnutls_state_st *state) | |
715 | { | |
716 | struct stat statbuf; | |
717 | int rc; | |
718 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
719 | uschar *saved_tls_certificate = NULL; | |
720 | uschar *saved_tls_privatekey = NULL; | |
721 | uschar *saved_tls_verify_certificates = NULL; | |
722 | uschar *saved_tls_crl = NULL; | |
723 | int cert_count; | |
724 | ||
725 | /* We check for tls_sni *before* expansion. */ | |
726 | if (!host) /* server */ | |
727 | { | |
728 | if (!state->received_sni) | |
729 | { | |
730 | if (state->tls_certificate && | |
731 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
732 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
733 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
734 | )) | |
735 | { | |
736 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
737 | state->trigger_sni_changes = TRUE; | |
738 | } | |
739 | } | |
740 | else | |
741 | { | |
742 | /* useful for debugging */ | |
743 | saved_tls_certificate = state->exp_tls_certificate; | |
744 | saved_tls_privatekey = state->exp_tls_privatekey; | |
745 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
746 | saved_tls_crl = state->exp_tls_crl; | |
747 | } | |
748 | } | |
749 | ||
750 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); | |
751 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
752 | ||
753 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with | |
754 | state members, assuming consistent naming; and expand_check() returns | |
755 | false if expansion failed, unless expansion was forced to fail. */ | |
756 | ||
757 | /* check if we at least have a certificate, before doing expensive | |
758 | D-H generation. */ | |
759 | ||
760 | if (!expand_check_tlsvar(tls_certificate)) | |
761 | return DEFER; | |
762 | ||
763 | /* certificate is mandatory in server, optional in client */ | |
764 | ||
765 | if ((state->exp_tls_certificate == NULL) || | |
766 | (*state->exp_tls_certificate == '\0')) | |
767 | { | |
768 | if (!host) | |
769 | return tls_error(US"no TLS server certificate is specified", NULL, NULL); | |
770 | else | |
771 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
772 | } | |
773 | ||
774 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) | |
775 | return DEFER; | |
776 | ||
777 | /* tls_privatekey is optional, defaulting to same file as certificate */ | |
778 | ||
779 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
780 | { | |
781 | state->tls_privatekey = state->tls_certificate; | |
782 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
783 | } | |
784 | ||
785 | ||
786 | if (state->exp_tls_certificate && *state->exp_tls_certificate) | |
787 | { | |
788 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
789 | state->exp_tls_certificate, state->exp_tls_privatekey); | |
790 | ||
791 | if (state->received_sni) | |
792 | { | |
793 | if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && | |
794 | (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) | |
795 | { | |
796 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); | |
797 | } | |
798 | else | |
799 | { | |
800 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); | |
801 | } | |
802 | } | |
803 | ||
804 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, | |
805 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
806 | GNUTLS_X509_FMT_PEM); | |
807 | exim_gnutls_err_check( | |
808 | string_sprintf("cert/key setup: cert=%s key=%s", | |
809 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
810 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
811 | } /* tls_certificate */ | |
812 | ||
813 | ||
814 | /* Set the OCSP stapling server info */ | |
815 | ||
816 | #ifndef DISABLE_OCSP | |
817 | if ( !host /* server */ | |
818 | && tls_ocsp_file | |
819 | ) | |
820 | { | |
821 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", | |
822 | &state->exp_tls_ocsp_file)) | |
823 | return DEFER; | |
824 | ||
825 | /* Use the full callback method for stapling just to get observability. | |
826 | More efficient would be to read the file once only, if it never changed | |
827 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
828 | ||
829 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, | |
830 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
831 | ||
832 | DEBUG(D_tls) debug_printf("Set OCSP response file %s\n", &state->exp_tls_ocsp_file); | |
833 | } | |
834 | #endif | |
835 | ||
836 | ||
837 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is | |
838 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
839 | error message is provided. However, if we just refrain from setting anything up | |
840 | in that case, certificate verification fails, which seems to be the correct | |
841 | behaviour. */ | |
842 | ||
843 | if (state->tls_verify_certificates && *state->tls_verify_certificates) | |
844 | { | |
845 | if (!expand_check_tlsvar(tls_verify_certificates)) | |
846 | return DEFER; | |
847 | if (state->tls_crl && *state->tls_crl) | |
848 | if (!expand_check_tlsvar(tls_crl)) | |
849 | return DEFER; | |
850 | ||
851 | if (!(state->exp_tls_verify_certificates && | |
852 | *state->exp_tls_verify_certificates)) | |
853 | { | |
854 | DEBUG(D_tls) | |
855 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); | |
856 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
857 | return OK; | |
858 | } | |
859 | } | |
860 | else | |
861 | { | |
862 | DEBUG(D_tls) | |
863 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
864 | return OK; | |
865 | } | |
866 | ||
867 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) | |
868 | { | |
869 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
870 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
871 | strerror(errno)); | |
872 | return DEFER; | |
873 | } | |
874 | ||
875 | /* The test suite passes in /dev/null; we could check for that path explicitly, | |
876 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
877 | other weirdness. The thing we really want to check is that it's not a | |
878 | directory, since while OpenSSL supports that, GnuTLS does not. | |
879 | So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ | |
880 | if (S_ISDIR(statbuf.st_mode)) | |
881 | { | |
882 | DEBUG(D_tls) | |
883 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
884 | state->exp_tls_verify_certificates); | |
885 | log_write(0, LOG_MAIN|LOG_PANIC, | |
886 | "tls_verify_certificates \"%s\" is a directory", | |
887 | state->exp_tls_verify_certificates); | |
888 | return DEFER; | |
889 | } | |
890 | ||
891 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", | |
892 | state->exp_tls_verify_certificates, statbuf.st_size); | |
893 | ||
894 | if (statbuf.st_size == 0) | |
895 | { | |
896 | DEBUG(D_tls) | |
897 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
898 | return OK; | |
899 | } | |
900 | ||
901 | cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, | |
902 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
903 | if (cert_count < 0) | |
904 | { | |
905 | rc = cert_count; | |
906 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); | |
907 | } | |
908 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
909 | ||
910 | if (state->tls_crl && *state->tls_crl && | |
911 | state->exp_tls_crl && *state->exp_tls_crl) | |
912 | { | |
913 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); | |
914 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
915 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
916 | if (cert_count < 0) | |
917 | { | |
918 | rc = cert_count; | |
919 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); | |
920 | } | |
921 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); | |
922 | } | |
923 | ||
924 | return OK; | |
925 | } | |
926 | ||
927 | ||
928 | ||
929 | ||
930 | /************************************************* | |
931 | * Set X.509 state variables * | |
932 | *************************************************/ | |
933 | ||
934 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
935 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
936 | structure. Which means various other non-re-expanded pieces of state | |
937 | need to be re-set in the new struct, so the setting logic is pulled | |
938 | out to this. | |
939 | ||
940 | Arguments: | |
941 | state exim_gnutls_state_st * | |
942 | ||
943 | Returns: OK/DEFER/FAIL | |
944 | */ | |
945 | ||
946 | static int | |
947 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
948 | { | |
949 | int rc; | |
950 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
951 | ||
952 | /* Create D-H parameters, or read them from the cache file. This function does | |
953 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
954 | client-side params. */ | |
955 | ||
956 | if (!state->host) | |
957 | { | |
958 | if (!dh_server_params) | |
959 | { | |
960 | rc = init_server_dh(); | |
961 | if (rc != OK) return rc; | |
962 | } | |
963 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
964 | } | |
965 | ||
966 | /* Link the credentials to the session. */ | |
967 | ||
968 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
969 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
970 | ||
971 | return OK; | |
972 | } | |
973 | ||
974 | /************************************************* | |
975 | * Initialize for GnuTLS * | |
976 | *************************************************/ | |
977 | ||
978 | /* Called from both server and client code. In the case of a server, errors | |
979 | before actual TLS negotiation return DEFER. | |
980 | ||
981 | Arguments: | |
982 | host connected host, if client; NULL if server | |
983 | certificate certificate file | |
984 | privatekey private key file | |
985 | sni TLS SNI to send, sometimes when client; else NULL | |
986 | cas CA certs file | |
987 | crl CRL file | |
988 | require_ciphers tls_require_ciphers setting | |
989 | caller_state returned state-info structure | |
990 | ||
991 | Returns: OK/DEFER/FAIL | |
992 | */ | |
993 | ||
994 | static int | |
995 | tls_init( | |
996 | const host_item *host, | |
997 | const uschar *certificate, | |
998 | const uschar *privatekey, | |
999 | const uschar *sni, | |
1000 | const uschar *cas, | |
1001 | const uschar *crl, | |
1002 | const uschar *require_ciphers, | |
1003 | exim_gnutls_state_st **caller_state) | |
1004 | { | |
1005 | exim_gnutls_state_st *state; | |
1006 | int rc; | |
1007 | size_t sz; | |
1008 | const char *errpos; | |
1009 | uschar *p; | |
1010 | BOOL want_default_priorities; | |
1011 | ||
1012 | if (!exim_gnutls_base_init_done) | |
1013 | { | |
1014 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); | |
1015 | ||
1016 | #ifdef HAVE_GNUTLS_PKCS11 | |
1017 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1018 | which loads modules from a config file, which sounds good and may be wanted | |
1019 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1020 | environment variables are used and so breaks for users calling mailq. | |
1021 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
1022 | if (!gnutls_allow_auto_pkcs11) | |
1023 | { | |
1024 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1025 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1026 | } | |
1027 | #endif | |
1028 | ||
1029 | rc = gnutls_global_init(); | |
1030 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1031 | ||
1032 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1033 | DEBUG(D_tls) | |
1034 | { | |
1035 | gnutls_global_set_log_function(exim_gnutls_logger_cb); | |
1036 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1037 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
1038 | } | |
1039 | #endif | |
1040 | ||
1041 | exim_gnutls_base_init_done = TRUE; | |
1042 | } | |
1043 | ||
1044 | if (host) | |
1045 | { | |
1046 | state = &state_client; | |
1047 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
1048 | state->tlsp = &tls_out; | |
1049 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); | |
1050 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1051 | } | |
1052 | else | |
1053 | { | |
1054 | state = &state_server; | |
1055 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
1056 | state->tlsp = &tls_in; | |
1057 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); | |
1058 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1059 | } | |
1060 | exim_gnutls_err_check(US"gnutls_init"); | |
1061 | ||
1062 | state->host = host; | |
1063 | ||
1064 | state->tls_certificate = certificate; | |
1065 | state->tls_privatekey = privatekey; | |
1066 | state->tls_require_ciphers = require_ciphers; | |
1067 | state->tls_sni = sni; | |
1068 | state->tls_verify_certificates = cas; | |
1069 | state->tls_crl = crl; | |
1070 | ||
1071 | /* This handles the variables that might get re-expanded after TLS SNI; | |
1072 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
1073 | ||
1074 | DEBUG(D_tls) | |
1075 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
1076 | rc = tls_expand_session_files(state); | |
1077 | if (rc != OK) return rc; | |
1078 | ||
1079 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS | |
1080 | requires a new structure afterwards. */ | |
1081 | ||
1082 | rc = tls_set_remaining_x509(state); | |
1083 | if (rc != OK) return rc; | |
1084 | ||
1085 | /* set SNI in client, only */ | |
1086 | if (host) | |
1087 | { | |
1088 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni)) | |
1089 | return DEFER; | |
1090 | if (state->tlsp->sni && *state->tlsp->sni) | |
1091 | { | |
1092 | DEBUG(D_tls) | |
1093 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); | |
1094 | sz = Ustrlen(state->tlsp->sni); | |
1095 | rc = gnutls_server_name_set(state->session, | |
1096 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); | |
1097 | exim_gnutls_err_check(US"gnutls_server_name_set"); | |
1098 | } | |
1099 | } | |
1100 | else if (state->tls_sni) | |
1101 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1102 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
1103 | ||
1104 | /* This is the priority string support, | |
1105 | http://www.gnutls.org/manual/html_node/Priority-Strings.html | |
1106 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. | |
1107 | This was backwards incompatible, but means Exim no longer needs to track | |
1108 | all algorithms and provide string forms for them. */ | |
1109 | ||
1110 | want_default_priorities = TRUE; | |
1111 | ||
1112 | if (state->tls_require_ciphers && *state->tls_require_ciphers) | |
1113 | { | |
1114 | if (!expand_check_tlsvar(tls_require_ciphers)) | |
1115 | return DEFER; | |
1116 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
1117 | { | |
1118 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", | |
1119 | state->exp_tls_require_ciphers); | |
1120 | ||
1121 | rc = gnutls_priority_init(&state->priority_cache, | |
1122 | CS state->exp_tls_require_ciphers, &errpos); | |
1123 | want_default_priorities = FALSE; | |
1124 | p = state->exp_tls_require_ciphers; | |
1125 | } | |
1126 | } | |
1127 | if (want_default_priorities) | |
1128 | { | |
1129 | DEBUG(D_tls) | |
1130 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1131 | exim_default_gnutls_priority); | |
1132 | rc = gnutls_priority_init(&state->priority_cache, | |
1133 | exim_default_gnutls_priority, &errpos); | |
1134 | p = US exim_default_gnutls_priority; | |
1135 | } | |
1136 | ||
1137 | exim_gnutls_err_check(string_sprintf( | |
1138 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1139 | p, errpos - CS p, errpos)); | |
1140 | ||
1141 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1142 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1143 | ||
1144 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1145 | ||
1146 | /* Reduce security in favour of increased compatibility, if the admin | |
1147 | decides to make that trade-off. */ | |
1148 | if (gnutls_compat_mode) | |
1149 | { | |
1150 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 | |
1151 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1152 | gnutls_session_enable_compatibility_mode(state->session); | |
1153 | #else | |
1154 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1155 | #endif | |
1156 | } | |
1157 | ||
1158 | *caller_state = state; | |
1159 | return OK; | |
1160 | } | |
1161 | ||
1162 | ||
1163 | ||
1164 | /************************************************* | |
1165 | * Extract peer information * | |
1166 | *************************************************/ | |
1167 | ||
1168 | /* Called from both server and client code. | |
1169 | Only this is allowed to set state->peerdn and state->have_set_peerdn | |
1170 | and we use that to detect double-calls. | |
1171 | ||
1172 | NOTE: the state blocks last while the TLS connection is up, which is fine | |
1173 | for logging in the server side, but for the client side, we log after teardown | |
1174 | in src/deliver.c. While the session is up, we can twist about states and | |
1175 | repoint tls_* globals, but those variables used for logging or other variable | |
1176 | expansion that happens _after_ delivery need to have a longer life-time. | |
1177 | ||
1178 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1179 | doing this more than once per generation of a state context. We set them in | |
1180 | the state context, and repoint tls_* to them. After the state goes away, the | |
1181 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1182 | ||
1183 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1184 | don't apply. | |
1185 | ||
1186 | Arguments: | |
1187 | state exim_gnutls_state_st * | |
1188 | ||
1189 | Returns: OK/DEFER/FAIL | |
1190 | */ | |
1191 | ||
1192 | static int | |
1193 | peer_status(exim_gnutls_state_st *state) | |
1194 | { | |
1195 | uschar cipherbuf[256]; | |
1196 | const gnutls_datum *cert_list; | |
1197 | int old_pool, rc; | |
1198 | unsigned int cert_list_size = 0; | |
1199 | gnutls_protocol_t protocol; | |
1200 | gnutls_cipher_algorithm_t cipher; | |
1201 | gnutls_kx_algorithm_t kx; | |
1202 | gnutls_mac_algorithm_t mac; | |
1203 | gnutls_certificate_type_t ct; | |
1204 | gnutls_x509_crt_t crt; | |
1205 | uschar *p, *dn_buf; | |
1206 | size_t sz; | |
1207 | ||
1208 | if (state->have_set_peerdn) | |
1209 | return OK; | |
1210 | state->have_set_peerdn = TRUE; | |
1211 | ||
1212 | state->peerdn = NULL; | |
1213 | ||
1214 | /* tls_cipher */ | |
1215 | cipher = gnutls_cipher_get(state->session); | |
1216 | protocol = gnutls_protocol_get_version(state->session); | |
1217 | mac = gnutls_mac_get(state->session); | |
1218 | kx = gnutls_kx_get(state->session); | |
1219 | ||
1220 | string_format(cipherbuf, sizeof(cipherbuf), | |
1221 | "%s:%s:%d", | |
1222 | gnutls_protocol_get_name(protocol), | |
1223 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1224 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1225 | ||
1226 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1227 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1228 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
1229 | for (p = cipherbuf; *p != '\0'; ++p) | |
1230 | if (isspace(*p)) | |
1231 | *p = '-'; | |
1232 | old_pool = store_pool; | |
1233 | store_pool = POOL_PERM; | |
1234 | state->ciphersuite = string_copy(cipherbuf); | |
1235 | store_pool = old_pool; | |
1236 | state->tlsp->cipher = state->ciphersuite; | |
1237 | ||
1238 | /* tls_peerdn */ | |
1239 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); | |
1240 | ||
1241 | if (cert_list == NULL || cert_list_size == 0) | |
1242 | { | |
1243 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", | |
1244 | cert_list, cert_list_size); | |
1245 | if (state->verify_requirement >= VERIFY_REQUIRED) | |
1246 | return tls_error(US"certificate verification failed", | |
1247 | "no certificate received from peer", state->host); | |
1248 | return OK; | |
1249 | } | |
1250 | ||
1251 | ct = gnutls_certificate_type_get(state->session); | |
1252 | if (ct != GNUTLS_CRT_X509) | |
1253 | { | |
1254 | const char *ctn = gnutls_certificate_type_get_name(ct); | |
1255 | DEBUG(D_tls) | |
1256 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
1257 | if (state->verify_requirement >= VERIFY_REQUIRED) | |
1258 | return tls_error(US"certificate verification not possible, unhandled type", | |
1259 | ctn, state->host); | |
1260 | return OK; | |
1261 | } | |
1262 | ||
1263 | #define exim_gnutls_peer_err(Label) \ | |
1264 | do { \ | |
1265 | if (rc != GNUTLS_E_SUCCESS) \ | |
1266 | { \ | |
1267 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1268 | (Label), gnutls_strerror(rc)); \ | |
1269 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
1270 | return tls_error((Label), gnutls_strerror(rc), state->host); \ | |
1271 | return OK; \ | |
1272 | } \ | |
1273 | } while (0) | |
1274 | ||
1275 | rc = import_cert(&cert_list[0], &crt); | |
1276 | exim_gnutls_peer_err(US"cert 0"); | |
1277 | ||
1278 | state->tlsp->peercert = state->peercert = crt; | |
1279 | ||
1280 | sz = 0; | |
1281 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1282 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
1283 | { | |
1284 | exim_gnutls_peer_err(US"getting size for cert DN failed"); | |
1285 | return FAIL; /* should not happen */ | |
1286 | } | |
1287 | dn_buf = store_get_perm(sz); | |
1288 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1289 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
1290 | ||
1291 | state->peerdn = dn_buf; | |
1292 | ||
1293 | return OK; | |
1294 | #undef exim_gnutls_peer_err | |
1295 | } | |
1296 | ||
1297 | ||
1298 | ||
1299 | ||
1300 | /************************************************* | |
1301 | * Verify peer certificate * | |
1302 | *************************************************/ | |
1303 | ||
1304 | /* Called from both server and client code. | |
1305 | *Should* be using a callback registered with | |
1306 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1307 | the peer information, but that's too new for some OSes. | |
1308 | ||
1309 | Arguments: | |
1310 | state exim_gnutls_state_st * | |
1311 | error where to put an error message | |
1312 | ||
1313 | Returns: | |
1314 | FALSE if the session should be rejected | |
1315 | TRUE if the cert is okay or we just don't care | |
1316 | */ | |
1317 | ||
1318 | static BOOL | |
1319 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1320 | { | |
1321 | int rc; | |
1322 | unsigned int verify; | |
1323 | ||
1324 | *error = NULL; | |
1325 | ||
1326 | if ((rc = peer_status(state)) != OK) | |
1327 | { | |
1328 | verify = GNUTLS_CERT_INVALID; | |
1329 | *error = "certificate not supplied"; | |
1330 | } | |
1331 | else | |
1332 | rc = gnutls_certificate_verify_peers2(state->session, &verify); | |
1333 | ||
1334 | /* Handle the result of verification. INVALID seems to be set as well | |
1335 | as REVOKED, but leave the test for both. */ | |
1336 | ||
1337 | if (rc < 0 || | |
1338 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1339 | ) | |
1340 | { | |
1341 | state->peer_cert_verified = FALSE; | |
1342 | if (!*error) | |
1343 | *error = verify & GNUTLS_CERT_REVOKED | |
1344 | ? "certificate revoked" : "certificate invalid"; | |
1345 | ||
1346 | DEBUG(D_tls) | |
1347 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", | |
1348 | *error, state->peerdn ? state->peerdn : US"<unset>"); | |
1349 | ||
1350 | if (state->verify_requirement >= VERIFY_REQUIRED) | |
1351 | { | |
1352 | gnutls_alert_send(state->session, | |
1353 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1354 | return FALSE; | |
1355 | } | |
1356 | DEBUG(D_tls) | |
1357 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); | |
1358 | } | |
1359 | ||
1360 | else | |
1361 | { | |
1362 | #ifdef EXPERIMENTAL_CERTNAMES | |
1363 | if (state->verify_requirement == VERIFY_WITHHOST) | |
1364 | { | |
1365 | int sep = 0; | |
1366 | uschar * list = state->exp_tls_verify_cert_hostnames; | |
1367 | uschar * name; | |
1368 | while (name = string_nextinlist(&list, &sep, NULL, 0)) | |
1369 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) | |
1370 | break; | |
1371 | if (!name) | |
1372 | { | |
1373 | DEBUG(D_tls) | |
1374 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
1375 | gnutls_alert_send(state->session, | |
1376 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1377 | return FALSE; | |
1378 | } | |
1379 | } | |
1380 | #endif | |
1381 | state->peer_cert_verified = TRUE; | |
1382 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", | |
1383 | state->peerdn ? state->peerdn : US"<unset>"); | |
1384 | } | |
1385 | ||
1386 | state->tlsp->peerdn = state->peerdn; | |
1387 | ||
1388 | return TRUE; | |
1389 | } | |
1390 | ||
1391 | ||
1392 | ||
1393 | ||
1394 | /* ------------------------------------------------------------------------ */ | |
1395 | /* Callbacks */ | |
1396 | ||
1397 | /* Logging function which can be registered with | |
1398 | * gnutls_global_set_log_function() | |
1399 | * gnutls_global_set_log_level() 0..9 | |
1400 | */ | |
1401 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1402 | static void | |
1403 | exim_gnutls_logger_cb(int level, const char *message) | |
1404 | { | |
1405 | size_t len = strlen(message); | |
1406 | if (len < 1) | |
1407 | { | |
1408 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1409 | return; | |
1410 | } | |
1411 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1412 | message[len-1] == '\n' ? "" : "\n"); | |
1413 | } | |
1414 | #endif | |
1415 | ||
1416 | ||
1417 | /* Called after client hello, should handle SNI work. | |
1418 | This will always set tls_sni (state->received_sni) if available, | |
1419 | and may trigger presenting different certificates, | |
1420 | if state->trigger_sni_changes is TRUE. | |
1421 | ||
1422 | Should be registered with | |
1423 | gnutls_handshake_set_post_client_hello_function() | |
1424 | ||
1425 | "This callback must return 0 on success or a gnutls error code to terminate the | |
1426 | handshake.". | |
1427 | ||
1428 | For inability to get SNI information, we return 0. | |
1429 | We only return non-zero if re-setup failed. | |
1430 | Only used for server-side TLS. | |
1431 | */ | |
1432 | ||
1433 | static int | |
1434 | exim_sni_handling_cb(gnutls_session_t session) | |
1435 | { | |
1436 | char sni_name[MAX_HOST_LEN]; | |
1437 | size_t data_len = MAX_HOST_LEN; | |
1438 | exim_gnutls_state_st *state = &state_server; | |
1439 | unsigned int sni_type; | |
1440 | int rc, old_pool; | |
1441 | ||
1442 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
1443 | if (rc != GNUTLS_E_SUCCESS) | |
1444 | { | |
1445 | DEBUG(D_tls) { | |
1446 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1447 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1448 | else | |
1449 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1450 | gnutls_strerror(rc), rc); | |
1451 | }; | |
1452 | return 0; | |
1453 | } | |
1454 | ||
1455 | if (sni_type != GNUTLS_NAME_DNS) | |
1456 | { | |
1457 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1458 | return 0; | |
1459 | } | |
1460 | ||
1461 | /* We now have a UTF-8 string in sni_name */ | |
1462 | old_pool = store_pool; | |
1463 | store_pool = POOL_PERM; | |
1464 | state->received_sni = string_copyn(US sni_name, data_len); | |
1465 | store_pool = old_pool; | |
1466 | ||
1467 | /* We set this one now so that variable expansions below will work */ | |
1468 | state->tlsp->sni = state->received_sni; | |
1469 | ||
1470 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1471 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1472 | ||
1473 | if (!state->trigger_sni_changes) | |
1474 | return 0; | |
1475 | ||
1476 | rc = tls_expand_session_files(state); | |
1477 | if (rc != OK) | |
1478 | { | |
1479 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1480 | been offered. The best we can do now is abort. */ | |
1481 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1482 | } | |
1483 | ||
1484 | rc = tls_set_remaining_x509(state); | |
1485 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1486 | ||
1487 | return 0; | |
1488 | } | |
1489 | ||
1490 | ||
1491 | ||
1492 | #ifndef DISABLE_OCSP | |
1493 | ||
1494 | static int | |
1495 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1496 | gnutls_datum_t * ocsp_response) | |
1497 | { | |
1498 | int ret; | |
1499 | ||
1500 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) | |
1501 | { | |
1502 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
1503 | (char *)ptr); | |
1504 | tls_in.ocsp = OCSP_NOT_RESP; | |
1505 | return GNUTLS_E_NO_CERTIFICATE_STATUS; | |
1506 | } | |
1507 | ||
1508 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; | |
1509 | return 0; | |
1510 | } | |
1511 | ||
1512 | #endif | |
1513 | ||
1514 | ||
1515 | ||
1516 | ||
1517 | ||
1518 | /* ------------------------------------------------------------------------ */ | |
1519 | /* Exported functions */ | |
1520 | ||
1521 | ||
1522 | ||
1523 | ||
1524 | /************************************************* | |
1525 | * Start a TLS session in a server * | |
1526 | *************************************************/ | |
1527 | ||
1528 | /* This is called when Exim is running as a server, after having received | |
1529 | the STARTTLS command. It must respond to that command, and then negotiate | |
1530 | a TLS session. | |
1531 | ||
1532 | Arguments: | |
1533 | require_ciphers list of allowed ciphers or NULL | |
1534 | ||
1535 | Returns: OK on success | |
1536 | DEFER for errors before the start of the negotiation | |
1537 | FAIL for errors during the negotation; the server can't | |
1538 | continue running. | |
1539 | */ | |
1540 | ||
1541 | int | |
1542 | tls_server_start(const uschar *require_ciphers) | |
1543 | { | |
1544 | int rc; | |
1545 | const char *error; | |
1546 | exim_gnutls_state_st *state = NULL; | |
1547 | ||
1548 | /* Check for previous activation */ | |
1549 | if (tls_in.active >= 0) | |
1550 | { | |
1551 | tls_error(US"STARTTLS received after TLS started", "", NULL); | |
1552 | smtp_printf("554 Already in TLS\r\n"); | |
1553 | return FAIL; | |
1554 | } | |
1555 | ||
1556 | /* Initialize the library. If it fails, it will already have logged the error | |
1557 | and sent an SMTP response. */ | |
1558 | ||
1559 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); | |
1560 | ||
1561 | rc = tls_init(NULL, tls_certificate, tls_privatekey, | |
1562 | NULL, tls_verify_certificates, tls_crl, | |
1563 | require_ciphers, &state); | |
1564 | if (rc != OK) return rc; | |
1565 | ||
1566 | /* If this is a host for which certificate verification is mandatory or | |
1567 | optional, set up appropriately. */ | |
1568 | ||
1569 | if (verify_check_host(&tls_verify_hosts) == OK) | |
1570 | { | |
1571 | DEBUG(D_tls) | |
1572 | debug_printf("TLS: a client certificate will be required.\n"); | |
1573 | state->verify_requirement = VERIFY_REQUIRED; | |
1574 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1575 | } | |
1576 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
1577 | { | |
1578 | DEBUG(D_tls) | |
1579 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
1580 | state->verify_requirement = VERIFY_OPTIONAL; | |
1581 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1582 | } | |
1583 | else | |
1584 | { | |
1585 | DEBUG(D_tls) | |
1586 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
1587 | state->verify_requirement = VERIFY_NONE; | |
1588 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1589 | } | |
1590 | ||
1591 | /* Register SNI handling; always, even if not in tls_certificate, so that the | |
1592 | expansion variable $tls_sni is always available. */ | |
1593 | ||
1594 | gnutls_handshake_set_post_client_hello_function(state->session, | |
1595 | exim_sni_handling_cb); | |
1596 | ||
1597 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1598 | on connection, where outputting anything now upsets the clients and tends to | |
1599 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1600 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1601 | mode, the fflush() happens when smtp_getc() is called. */ | |
1602 | ||
1603 | if (!state->tlsp->on_connect) | |
1604 | { | |
1605 | smtp_printf("220 TLS go ahead\r\n"); | |
1606 | fflush(smtp_out); | |
1607 | } | |
1608 | ||
1609 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1610 | that the GnuTLS library doesn't. */ | |
1611 | ||
1612 | gnutls_transport_set_ptr2(state->session, | |
1613 | (gnutls_transport_ptr)(long) fileno(smtp_in), | |
1614 | (gnutls_transport_ptr)(long) fileno(smtp_out)); | |
1615 | state->fd_in = fileno(smtp_in); | |
1616 | state->fd_out = fileno(smtp_out); | |
1617 | ||
1618 | sigalrm_seen = FALSE; | |
1619 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1620 | do | |
1621 | { | |
1622 | rc = gnutls_handshake(state->session); | |
1623 | } while ((rc == GNUTLS_E_AGAIN) || | |
1624 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
1625 | alarm(0); | |
1626 | ||
1627 | if (rc != GNUTLS_E_SUCCESS) | |
1628 | { | |
1629 | tls_error(US"gnutls_handshake", | |
1630 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
1631 | /* It seems that, except in the case of a timeout, we have to close the | |
1632 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1633 | until the server times out. */ | |
1634 | ||
1635 | if (!sigalrm_seen) | |
1636 | { | |
1637 | (void)fclose(smtp_out); | |
1638 | (void)fclose(smtp_in); | |
1639 | } | |
1640 | ||
1641 | return FAIL; | |
1642 | } | |
1643 | ||
1644 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1645 | ||
1646 | /* Verify after the fact */ | |
1647 | ||
1648 | if ( state->verify_requirement != VERIFY_NONE | |
1649 | && !verify_certificate(state, &error)) | |
1650 | { | |
1651 | if (state->verify_requirement != VERIFY_OPTIONAL) | |
1652 | { | |
1653 | tls_error(US"certificate verification failed", error, NULL); | |
1654 | return FAIL; | |
1655 | } | |
1656 | DEBUG(D_tls) | |
1657 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1658 | error); | |
1659 | } | |
1660 | ||
1661 | /* Figure out peer DN, and if authenticated, etc. */ | |
1662 | ||
1663 | rc = peer_status(state); | |
1664 | if (rc != OK) return rc; | |
1665 | ||
1666 | /* Sets various Exim expansion variables; always safe within server */ | |
1667 | ||
1668 | extract_exim_vars_from_tls_state(state); | |
1669 | ||
1670 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1671 | and initialize appropriately. */ | |
1672 | ||
1673 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); | |
1674 | ||
1675 | receive_getc = tls_getc; | |
1676 | receive_ungetc = tls_ungetc; | |
1677 | receive_feof = tls_feof; | |
1678 | receive_ferror = tls_ferror; | |
1679 | receive_smtp_buffered = tls_smtp_buffered; | |
1680 | ||
1681 | return OK; | |
1682 | } | |
1683 | ||
1684 | ||
1685 | ||
1686 | ||
1687 | /************************************************* | |
1688 | * Start a TLS session in a client * | |
1689 | *************************************************/ | |
1690 | ||
1691 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1692 | ||
1693 | Arguments: | |
1694 | fd the fd of the connection | |
1695 | host connected host (for messages) | |
1696 | addr the first address (not used) | |
1697 | ob smtp transport options | |
1698 | ||
1699 | Returns: OK/DEFER/FAIL (because using common functions), | |
1700 | but for a client, DEFER and FAIL have the same meaning | |
1701 | */ | |
1702 | ||
1703 | int | |
1704 | tls_client_start(int fd, host_item *host, | |
1705 | address_item *addr ARG_UNUSED, | |
1706 | void *v_ob) | |
1707 | { | |
1708 | smtp_transport_options_block *ob = v_ob; | |
1709 | int rc; | |
1710 | const char *error; | |
1711 | exim_gnutls_state_st *state = NULL; | |
1712 | #ifndef DISABLE_OCSP | |
1713 | BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, | |
1714 | NULL, host->name, host->address, NULL) == OK; | |
1715 | BOOL request_ocsp = require_ocsp ? TRUE | |
1716 | : verify_check_this_host(&ob->hosts_request_ocsp, | |
1717 | NULL, host->name, host->address, NULL) == OK; | |
1718 | #endif | |
1719 | ||
1720 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); | |
1721 | ||
1722 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, | |
1723 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
1724 | ob->tls_require_ciphers, &state)) != OK) | |
1725 | return rc; | |
1726 | ||
1727 | { | |
1728 | int dh_min_bits = ob->tls_dh_min_bits; | |
1729 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
1730 | { | |
1731 | DEBUG(D_tls) | |
1732 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
1733 | " clamping %d up to %d\n", | |
1734 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1735 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1736 | } | |
1737 | ||
1738 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" | |
1739 | " acceptable bits to %d\n", | |
1740 | dh_min_bits); | |
1741 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
1742 | } | |
1743 | ||
1744 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is | |
1745 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only | |
1746 | the specified host patterns if one of them is defined */ | |
1747 | ||
1748 | if (( state->exp_tls_verify_certificates | |
1749 | && !ob->tls_verify_hosts | |
1750 | && !ob->tls_try_verify_hosts | |
1751 | ) | |
1752 | || | |
1753 | verify_check_host(&ob->tls_verify_hosts) == OK | |
1754 | ) | |
1755 | { | |
1756 | #ifdef EXPERIMENTAL_CERTNAMES | |
1757 | if (ob->tls_verify_cert_hostnames) | |
1758 | { | |
1759 | DEBUG(D_tls) | |
1760 | debug_printf("TLS: server cert incl. hostname verification required.\n"); | |
1761 | state->verify_requirement = VERIFY_WITHHOST; | |
1762 | if (!expand_check(ob->tls_verify_cert_hostnames, | |
1763 | US"tls_verify_cert_hostnames", | |
1764 | &state->exp_tls_verify_cert_hostnames)) | |
1765 | return FAIL; | |
1766 | if (state->exp_tls_verify_cert_hostnames) | |
1767 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1768 | state->exp_tls_verify_cert_hostnames); | |
1769 | } | |
1770 | else | |
1771 | #endif | |
1772 | { | |
1773 | DEBUG(D_tls) | |
1774 | debug_printf("TLS: server certificate verification required.\n"); | |
1775 | state->verify_requirement = VERIFY_REQUIRED; | |
1776 | } | |
1777 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1778 | } | |
1779 | else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) | |
1780 | { | |
1781 | DEBUG(D_tls) | |
1782 | debug_printf("TLS: server certificate verification optional.\n"); | |
1783 | state->verify_requirement = VERIFY_OPTIONAL; | |
1784 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1785 | } | |
1786 | else | |
1787 | { | |
1788 | DEBUG(D_tls) | |
1789 | debug_printf("TLS: server certificate verification not required.\n"); | |
1790 | state->verify_requirement = VERIFY_NONE; | |
1791 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1792 | } | |
1793 | ||
1794 | #ifndef DISABLE_OCSP | |
1795 | /* supported since GnuTLS 3.1.3 */ | |
1796 | if (request_ocsp) | |
1797 | { | |
1798 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
1799 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, | |
1800 | NULL, 0, NULL)) != OK) | |
1801 | return tls_error(US"cert-status-req", | |
1802 | gnutls_strerror(rc), state->host); | |
1803 | tls_out.ocsp = OCSP_NOT_RESP; | |
1804 | } | |
1805 | #endif | |
1806 | ||
1807 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)(long) fd); | |
1808 | state->fd_in = fd; | |
1809 | state->fd_out = fd; | |
1810 | ||
1811 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); | |
1812 | /* There doesn't seem to be a built-in timeout on connection. */ | |
1813 | ||
1814 | sigalrm_seen = FALSE; | |
1815 | alarm(ob->command_timeout); | |
1816 | do | |
1817 | { | |
1818 | rc = gnutls_handshake(state->session); | |
1819 | } while ((rc == GNUTLS_E_AGAIN) || | |
1820 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
1821 | alarm(0); | |
1822 | ||
1823 | if (rc != GNUTLS_E_SUCCESS) | |
1824 | return tls_error(US"gnutls_handshake", | |
1825 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
1826 | ||
1827 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1828 | ||
1829 | /* Verify late */ | |
1830 | ||
1831 | if (state->verify_requirement != VERIFY_NONE && | |
1832 | !verify_certificate(state, &error)) | |
1833 | return tls_error(US"certificate verification failed", error, state->host); | |
1834 | ||
1835 | #ifndef DISABLE_OCSP | |
1836 | if (require_ocsp) | |
1837 | { | |
1838 | DEBUG(D_tls) | |
1839 | { | |
1840 | gnutls_datum_t stapling; | |
1841 | gnutls_ocsp_resp_t resp; | |
1842 | gnutls_datum_t printed; | |
1843 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
1844 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
1845 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
1846 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
1847 | ) | |
1848 | { | |
1849 | debug_printf("%.4096s", printed.data); | |
1850 | gnutls_free(printed.data); | |
1851 | } | |
1852 | else | |
1853 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); | |
1854 | } | |
1855 | ||
1856 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) | |
1857 | { | |
1858 | tls_out.ocsp = OCSP_FAILED; | |
1859 | return tls_error(US"certificate status check failed", NULL, state->host); | |
1860 | } | |
1861 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); | |
1862 | tls_out.ocsp = OCSP_VFIED; | |
1863 | } | |
1864 | #endif | |
1865 | ||
1866 | /* Figure out peer DN, and if authenticated, etc. */ | |
1867 | ||
1868 | if ((rc = peer_status(state)) != OK) | |
1869 | return rc; | |
1870 | ||
1871 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ | |
1872 | ||
1873 | extract_exim_vars_from_tls_state(state); | |
1874 | ||
1875 | return OK; | |
1876 | } | |
1877 | ||
1878 | ||
1879 | ||
1880 | ||
1881 | /************************************************* | |
1882 | * Close down a TLS session * | |
1883 | *************************************************/ | |
1884 | ||
1885 | /* This is also called from within a delivery subprocess forked from the | |
1886 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1887 | would tamper with the TLS session in the parent process). | |
1888 | ||
1889 | Arguments: TRUE if gnutls_bye is to be called | |
1890 | Returns: nothing | |
1891 | */ | |
1892 | ||
1893 | void | |
1894 | tls_close(BOOL is_server, BOOL shutdown) | |
1895 | { | |
1896 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; | |
1897 | ||
1898 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ | |
1899 | ||
1900 | if (shutdown) | |
1901 | { | |
1902 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1903 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
1904 | } | |
1905 | ||
1906 | gnutls_deinit(state->session); | |
1907 | ||
1908 | state->tlsp->active = -1; | |
1909 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
1910 | ||
1911 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
1912 | { | |
1913 | gnutls_global_deinit(); | |
1914 | exim_gnutls_base_init_done = FALSE; | |
1915 | } | |
1916 | ||
1917 | } | |
1918 | ||
1919 | ||
1920 | ||
1921 | ||
1922 | /************************************************* | |
1923 | * TLS version of getc * | |
1924 | *************************************************/ | |
1925 | ||
1926 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1927 | it refills the buffer via the GnuTLS reading function. | |
1928 | Only used by the server-side TLS. | |
1929 | ||
1930 | This feeds DKIM and should be used for all message-body reads. | |
1931 | ||
1932 | Arguments: none | |
1933 | Returns: the next character or EOF | |
1934 | */ | |
1935 | ||
1936 | int | |
1937 | tls_getc(void) | |
1938 | { | |
1939 | exim_gnutls_state_st *state = &state_server; | |
1940 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) | |
1941 | { | |
1942 | ssize_t inbytes; | |
1943 | ||
1944 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
1945 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
1946 | ||
1947 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1948 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
1949 | ssl_xfer_buffer_size); | |
1950 | alarm(0); | |
1951 | ||
1952 | /* A zero-byte return appears to mean that the TLS session has been | |
1953 | closed down, not that the socket itself has been closed down. Revert to | |
1954 | non-TLS handling. */ | |
1955 | ||
1956 | if (inbytes == 0) | |
1957 | { | |
1958 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1959 | ||
1960 | receive_getc = smtp_getc; | |
1961 | receive_ungetc = smtp_ungetc; | |
1962 | receive_feof = smtp_feof; | |
1963 | receive_ferror = smtp_ferror; | |
1964 | receive_smtp_buffered = smtp_buffered; | |
1965 | ||
1966 | gnutls_deinit(state->session); | |
1967 | state->session = NULL; | |
1968 | state->tlsp->active = -1; | |
1969 | state->tlsp->bits = 0; | |
1970 | state->tlsp->certificate_verified = FALSE; | |
1971 | tls_channelbinding_b64 = NULL; | |
1972 | state->tlsp->cipher = NULL; | |
1973 | state->tlsp->peercert = NULL; | |
1974 | state->tlsp->peerdn = NULL; | |
1975 | ||
1976 | return smtp_getc(); | |
1977 | } | |
1978 | ||
1979 | /* Handle genuine errors */ | |
1980 | ||
1981 | else if (inbytes < 0) | |
1982 | { | |
1983 | record_io_error(state, (int) inbytes, US"recv", NULL); | |
1984 | state->xfer_error = 1; | |
1985 | return EOF; | |
1986 | } | |
1987 | #ifndef DISABLE_DKIM | |
1988 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
1989 | #endif | |
1990 | state->xfer_buffer_hwm = (int) inbytes; | |
1991 | state->xfer_buffer_lwm = 0; | |
1992 | } | |
1993 | ||
1994 | /* Something in the buffer; return next uschar */ | |
1995 | ||
1996 | return state->xfer_buffer[state->xfer_buffer_lwm++]; | |
1997 | } | |
1998 | ||
1999 | ||
2000 | ||
2001 | ||
2002 | /************************************************* | |
2003 | * Read bytes from TLS channel * | |
2004 | *************************************************/ | |
2005 | ||
2006 | /* This does not feed DKIM, so if the caller uses this for reading message body, | |
2007 | then the caller must feed DKIM. | |
2008 | ||
2009 | Arguments: | |
2010 | buff buffer of data | |
2011 | len size of buffer | |
2012 | ||
2013 | Returns: the number of bytes read | |
2014 | -1 after a failed read | |
2015 | */ | |
2016 | ||
2017 | int | |
2018 | tls_read(BOOL is_server, uschar *buff, size_t len) | |
2019 | { | |
2020 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; | |
2021 | ssize_t inbytes; | |
2022 | ||
2023 | if (len > INT_MAX) | |
2024 | len = INT_MAX; | |
2025 | ||
2026 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) | |
2027 | DEBUG(D_tls) | |
2028 | debug_printf("*** PROBABLY A BUG *** " \ | |
2029 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2030 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2031 | ||
2032 | DEBUG(D_tls) | |
2033 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2034 | state->session, buff, len); | |
2035 | ||
2036 | inbytes = gnutls_record_recv(state->session, buff, len); | |
2037 | if (inbytes > 0) return inbytes; | |
2038 | if (inbytes == 0) | |
2039 | { | |
2040 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2041 | } | |
2042 | else record_io_error(state, (int)inbytes, US"recv", NULL); | |
2043 | ||
2044 | return -1; | |
2045 | } | |
2046 | ||
2047 | ||
2048 | ||
2049 | ||
2050 | /************************************************* | |
2051 | * Write bytes down TLS channel * | |
2052 | *************************************************/ | |
2053 | ||
2054 | /* | |
2055 | Arguments: | |
2056 | is_server channel specifier | |
2057 | buff buffer of data | |
2058 | len number of bytes | |
2059 | ||
2060 | Returns: the number of bytes after a successful write, | |
2061 | -1 after a failed write | |
2062 | */ | |
2063 | ||
2064 | int | |
2065 | tls_write(BOOL is_server, const uschar *buff, size_t len) | |
2066 | { | |
2067 | ssize_t outbytes; | |
2068 | size_t left = len; | |
2069 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; | |
2070 | ||
2071 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); | |
2072 | while (left > 0) | |
2073 | { | |
2074 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", | |
2075 | buff, left); | |
2076 | outbytes = gnutls_record_send(state->session, buff, left); | |
2077 | ||
2078 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); | |
2079 | if (outbytes < 0) | |
2080 | { | |
2081 | record_io_error(state, outbytes, US"send", NULL); | |
2082 | return -1; | |
2083 | } | |
2084 | if (outbytes == 0) | |
2085 | { | |
2086 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); | |
2087 | return -1; | |
2088 | } | |
2089 | ||
2090 | left -= outbytes; | |
2091 | buff += outbytes; | |
2092 | } | |
2093 | ||
2094 | if (len > INT_MAX) | |
2095 | { | |
2096 | DEBUG(D_tls) | |
2097 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2098 | len); | |
2099 | len = INT_MAX; | |
2100 | } | |
2101 | ||
2102 | return (int) len; | |
2103 | } | |
2104 | ||
2105 | ||
2106 | ||
2107 | ||
2108 | /************************************************* | |
2109 | * Random number generation * | |
2110 | *************************************************/ | |
2111 | ||
2112 | /* Pseudo-random number generation. The result is not expected to be | |
2113 | cryptographically strong but not so weak that someone will shoot themselves | |
2114 | in the foot using it as a nonce in input in some email header scheme or | |
2115 | whatever weirdness they'll twist this into. The result should handle fork() | |
2116 | and avoid repeating sequences. OpenSSL handles that for us. | |
2117 | ||
2118 | Arguments: | |
2119 | max range maximum | |
2120 | Returns a random number in range [0, max-1] | |
2121 | */ | |
2122 | ||
2123 | #ifdef HAVE_GNUTLS_RND | |
2124 | int | |
2125 | vaguely_random_number(int max) | |
2126 | { | |
2127 | unsigned int r; | |
2128 | int i, needed_len; | |
2129 | uschar *p; | |
2130 | uschar smallbuf[sizeof(r)]; | |
2131 | ||
2132 | if (max <= 1) | |
2133 | return 0; | |
2134 | ||
2135 | needed_len = sizeof(r); | |
2136 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2137 | * asked for a number less than 10. */ | |
2138 | for (r = max, i = 0; r; ++i) | |
2139 | r >>= 1; | |
2140 | i = (i + 7) / 8; | |
2141 | if (i < needed_len) | |
2142 | needed_len = i; | |
2143 | ||
2144 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2145 | if (i < 0) | |
2146 | { | |
2147 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); | |
2148 | return vaguely_random_number_fallback(max); | |
2149 | } | |
2150 | r = 0; | |
2151 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2152 | { | |
2153 | r *= 256; | |
2154 | r += *p; | |
2155 | } | |
2156 | ||
2157 | /* We don't particularly care about weighted results; if someone wants | |
2158 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2159 | return r % max; | |
2160 | } | |
2161 | #else /* HAVE_GNUTLS_RND */ | |
2162 | int | |
2163 | vaguely_random_number(int max) | |
2164 | { | |
2165 | return vaguely_random_number_fallback(max); | |
2166 | } | |
2167 | #endif /* HAVE_GNUTLS_RND */ | |
2168 | ||
2169 | ||
2170 | ||
2171 | ||
2172 | /************************************************* | |
2173 | * Let tls_require_ciphers be checked at startup * | |
2174 | *************************************************/ | |
2175 | ||
2176 | /* The tls_require_ciphers option, if set, must be something which the | |
2177 | library can parse. | |
2178 | ||
2179 | Returns: NULL on success, or error message | |
2180 | */ | |
2181 | ||
2182 | uschar * | |
2183 | tls_validate_require_cipher(void) | |
2184 | { | |
2185 | int rc; | |
2186 | uschar *expciphers = NULL; | |
2187 | gnutls_priority_t priority_cache; | |
2188 | const char *errpos; | |
2189 | ||
2190 | #define validate_check_rc(Label) do { \ | |
2191 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2192 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2193 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2194 | ||
2195 | if (exim_gnutls_base_init_done) | |
2196 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2197 | "already initialised GnuTLS, Exim developer bug"); | |
2198 | ||
2199 | #ifdef HAVE_GNUTLS_PKCS11 | |
2200 | if (!gnutls_allow_auto_pkcs11) | |
2201 | { | |
2202 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2203 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2204 | } | |
2205 | #endif | |
2206 | rc = gnutls_global_init(); | |
2207 | validate_check_rc(US"gnutls_global_init()"); | |
2208 | exim_gnutls_base_init_done = TRUE; | |
2209 | ||
2210 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2211 | return_deinit(NULL); | |
2212 | ||
2213 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2214 | return_deinit(US"failed to expand tls_require_ciphers"); | |
2215 | ||
2216 | if (!(expciphers && *expciphers)) | |
2217 | return_deinit(NULL); | |
2218 | ||
2219 | DEBUG(D_tls) | |
2220 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2221 | ||
2222 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2223 | validate_check_rc(string_sprintf( | |
2224 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2225 | expciphers, errpos - CS expciphers, errpos)); | |
2226 | ||
2227 | #undef return_deinit | |
2228 | #undef validate_check_rc | |
2229 | gnutls_global_deinit(); | |
2230 | ||
2231 | return NULL; | |
2232 | } | |
2233 | ||
2234 | ||
2235 | ||
2236 | ||
2237 | /************************************************* | |
2238 | * Report the library versions. * | |
2239 | *************************************************/ | |
2240 | ||
2241 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2242 | ||
2243 | Arguments: a FILE* to print the results to | |
2244 | Returns: nothing | |
2245 | */ | |
2246 | ||
2247 | void | |
2248 | tls_version_report(FILE *f) | |
2249 | { | |
2250 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" | |
2251 | " Runtime: %s\n", | |
2252 | LIBGNUTLS_VERSION, | |
2253 | gnutls_check_version(NULL)); | |
2254 | } | |
2255 | ||
2256 | /* vi: aw ai sw=2 | |
2257 | */ | |
2258 | /* End of tls-gnu.c */ |