Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
3386088d | 5 | /* Copyright (c) University of Cambridge 1995 - 2015 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
17c76198 | 8 | /* Copyright (c) Phil Pennock 2012 */ |
059ec3d9 | 9 | |
17c76198 PP |
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. | |
059ec3d9 | 13 | |
17c76198 PP |
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. | |
059ec3d9 | 18 | |
17c76198 PP |
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). | |
059ec3d9 | 23 | |
17c76198 PP |
24 | Keeping client and server variables more split than before and is currently |
25 | the norm, in anticipation of TLS in ACL callouts. | |
059ec3d9 | 26 | |
17c76198 PP |
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. | |
059ec3d9 | 31 | |
17c76198 PP |
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 | */ | |
b5aea5e1 | 36 | |
17c76198 PP |
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> | |
a5f239e4 PP |
42 | /* needed to disable PKCS11 autoload unless requested */ |
43 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
44 | # include <gnutls/pkcs11.h> | |
45 | #endif | |
7e07527a JH |
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 | |
0cbf2b82 | 50 | #if GNUTLS_VERSION_NUMBER < 0x020a00 && !defined(DISABLE_EVENT) |
774ef2d7 | 51 | # warning "GnuTLS library version too old; tls:cert event unsupported" |
0cbf2b82 | 52 | # define DISABLE_EVENT |
a7538db1 | 53 | #endif |
a7fec7a7 JH |
54 | #if GNUTLS_VERSION_NUMBER >= 0x030306 |
55 | # define SUPPORT_CA_DIR | |
56 | #else | |
57 | # undef SUPPORT_CA_DIR | |
58 | #endif | |
11a04b5a | 59 | #if GNUTLS_VERSION_NUMBER >= 0x030014 |
cb1d7830 JH |
60 | # define SUPPORT_SYSDEFAULT_CABUNDLE |
61 | #endif | |
7e07527a | 62 | |
f2de3a33 | 63 | #ifndef DISABLE_OCSP |
2b4a568d JH |
64 | # include <gnutls/ocsp.h> |
65 | #endif | |
059ec3d9 | 66 | |
17c76198 | 67 | /* GnuTLS 2 vs 3 |
059ec3d9 | 68 | |
17c76198 PP |
69 | GnuTLS 3 only: |
70 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 71 | |
17c76198 PP |
72 | Changes: |
73 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
74 | */ | |
059ec3d9 | 75 | |
17c76198 | 76 | /* Local static variables for GnuTLS */ |
059ec3d9 | 77 | |
17c76198 | 78 | /* Values for verify_requirement */ |
059ec3d9 | 79 | |
e51c7be2 | 80 | enum peer_verify_requirement |
aa2a70ba | 81 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 82 | |
17c76198 PP |
83 | /* This holds most state for server or client; with this, we can set up an |
84 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
85 | over the TLS variables available for expansion. | |
059ec3d9 | 86 | |
17c76198 PP |
87 | Some of these correspond to variables in globals.c; those variables will |
88 | be set to point to content in one of these instances, as appropriate for | |
89 | the stage of the process lifetime. | |
059ec3d9 | 90 | |
389ca47a | 91 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 92 | */ |
059ec3d9 | 93 | |
17c76198 | 94 | typedef struct exim_gnutls_state { |
9d1c15ef | 95 | gnutls_session_t session; |
17c76198 | 96 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 97 | gnutls_priority_t priority_cache; |
17c76198 | 98 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
99 | int fd_in; |
100 | int fd_out; | |
101 | BOOL peer_cert_verified; | |
102 | BOOL trigger_sni_changes; | |
103 | BOOL have_set_peerdn; | |
17c76198 | 104 | const struct host_item *host; |
9d1c15ef JH |
105 | gnutls_x509_crt_t peercert; |
106 | uschar *peerdn; | |
107 | uschar *ciphersuite; | |
108 | uschar *received_sni; | |
17c76198 PP |
109 | |
110 | const uschar *tls_certificate; | |
111 | const uschar *tls_privatekey; | |
112 | const uschar *tls_sni; /* client send only, not received */ | |
113 | const uschar *tls_verify_certificates; | |
114 | const uschar *tls_crl; | |
115 | const uschar *tls_require_ciphers; | |
e51c7be2 | 116 | |
17c76198 PP |
117 | uschar *exp_tls_certificate; |
118 | uschar *exp_tls_privatekey; | |
17c76198 PP |
119 | uschar *exp_tls_verify_certificates; |
120 | uschar *exp_tls_crl; | |
121 | uschar *exp_tls_require_ciphers; | |
44662487 | 122 | uschar *exp_tls_ocsp_file; |
55414b25 | 123 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 124 | #ifndef DISABLE_EVENT |
a7538db1 JH |
125 | uschar *event_action; |
126 | #endif | |
17c76198 | 127 | |
389ca47a | 128 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 129 | |
17c76198 PP |
130 | uschar *xfer_buffer; |
131 | int xfer_buffer_lwm; | |
132 | int xfer_buffer_hwm; | |
133 | int xfer_eof; | |
134 | int xfer_error; | |
17c76198 PP |
135 | } exim_gnutls_state_st; |
136 | ||
137 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 138 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 139 | NULL, NULL, NULL, NULL, |
17c76198 | 140 | NULL, NULL, NULL, NULL, NULL, NULL, |
44662487 | 141 | NULL, NULL, NULL, NULL, NULL, NULL, NULL, |
01a4a5c5 | 142 | NULL, |
0cbf2b82 | 143 | #ifndef DISABLE_EVENT |
a7538db1 | 144 | NULL, |
e51c7be2 | 145 | #endif |
817d9f57 | 146 | NULL, |
17c76198 | 147 | NULL, 0, 0, 0, 0, |
17c76198 | 148 | }; |
83da1223 | 149 | |
17c76198 PP |
150 | /* Not only do we have our own APIs which don't pass around state, assuming |
151 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
152 | for callbacks, or as part of the session, so we have to keep a "this is the | |
153 | context we're currently dealing with" pointer and rely upon being | |
154 | single-threaded to keep from processing data on an inbound TLS connection while | |
155 | talking to another TLS connection for an outbound check. This does mean that | |
156 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
157 | second connection. |
158 | XXX But see gnutls_session_get_ptr() | |
159 | */ | |
059ec3d9 | 160 | |
17c76198 | 161 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 162 | |
17c76198 PP |
163 | /* dh_params are initialised once within the lifetime of a process using TLS; |
164 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
165 | don't want to repeat this. */ | |
83da1223 | 166 | |
17c76198 | 167 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 168 | |
17c76198 | 169 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 170 | |
17c76198 | 171 | static const int ssl_session_timeout = 200; |
059ec3d9 | 172 | |
17c76198 | 173 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 174 | |
17c76198 | 175 | /* Guard library core initialisation */ |
83da1223 | 176 | |
17c76198 | 177 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 178 | |
4fb7df6d | 179 | #ifndef DISABLE_OCSP |
9196d5bf | 180 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 181 | #endif |
9196d5bf | 182 | |
059ec3d9 | 183 | |
17c76198 PP |
184 | /* ------------------------------------------------------------------------ */ |
185 | /* macros */ | |
83da1223 | 186 | |
17c76198 | 187 | #define MAX_HOST_LEN 255 |
83da1223 | 188 | |
17c76198 PP |
189 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
190 | the library logging; a value less than 0 disables the calls to set up logging | |
191 | callbacks. */ | |
2c17bb02 | 192 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 193 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 194 | #endif |
83da1223 | 195 | |
2c17bb02 | 196 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 197 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 198 | #endif |
83da1223 | 199 | |
af3498d6 PP |
200 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
201 | can ask for a bit-strength. Without that, we stick to the constant we had | |
202 | before, for now. */ | |
2c17bb02 | 203 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 204 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 205 | #endif |
af3498d6 | 206 | |
17c76198 PP |
207 | #define exim_gnutls_err_check(Label) do { \ |
208 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 209 | |
17c76198 | 210 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 211 | |
17c76198 | 212 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
213 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
214 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
215 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
216 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
217 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
218 | * isn't available sometimes, so this needs to become a conditional | |
219 | * compilation; the sanest way to deal with this being a problem on | |
220 | * older OSes is to block it in the Local/Makefile with this compiler | |
221 | * definition */ | |
e51c7be2 JH |
222 | # ifndef AVOID_GNUTLS_PKCS11 |
223 | # define HAVE_GNUTLS_PKCS11 | |
224 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 225 | #endif |
83da1223 | 226 | |
af3498d6 PP |
227 | |
228 | ||
229 | ||
230 | /* ------------------------------------------------------------------------ */ | |
231 | /* Callback declarations */ | |
232 | ||
233 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
234 | static void exim_gnutls_logger_cb(int level, const char *message); | |
235 | #endif | |
236 | ||
237 | static int exim_sni_handling_cb(gnutls_session_t session); | |
238 | ||
f2de3a33 | 239 | #ifndef DISABLE_OCSP |
44662487 JH |
240 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
241 | gnutls_datum_t * ocsp_response); | |
242 | #endif | |
af3498d6 PP |
243 | |
244 | ||
245 | ||
17c76198 PP |
246 | /* ------------------------------------------------------------------------ */ |
247 | /* Static functions */ | |
059ec3d9 PH |
248 | |
249 | /************************************************* | |
250 | * Handle TLS error * | |
251 | *************************************************/ | |
252 | ||
253 | /* Called from lots of places when errors occur before actually starting to do | |
254 | the TLS handshake, that is, while the session is still in clear. Always returns | |
255 | DEFER for a server and FAIL for a client so that most calls can use "return | |
256 | tls_error(...)" to do this processing and then give an appropriate return. A | |
257 | single function is used for both server and client, because it is called from | |
258 | some shared functions. | |
259 | ||
260 | Argument: | |
261 | prefix text to include in the logged error | |
7199e1ee TF |
262 | msg additional error string (may be NULL) |
263 | usually obtained from gnutls_strerror() | |
17c76198 PP |
264 | host NULL if setting up a server; |
265 | the connected host if setting up a client | |
059ec3d9 PH |
266 | |
267 | Returns: OK/DEFER/FAIL | |
268 | */ | |
269 | ||
270 | static int | |
17c76198 | 271 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 272 | { |
17c76198 PP |
273 | if (host) |
274 | { | |
c562fd30 | 275 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s)%s%s", |
17c76198 PP |
276 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); |
277 | return FAIL; | |
278 | } | |
279 | else | |
059ec3d9 | 280 | { |
7199e1ee | 281 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 282 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee | 283 | conn_info += 5; |
c562fd30 | 284 | /* I'd like to get separated H= here, but too hard for now */ |
7199e1ee | 285 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", |
17c76198 | 286 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
287 | return DEFER; |
288 | } | |
059ec3d9 PH |
289 | } |
290 | ||
291 | ||
292 | ||
17c76198 | 293 | |
059ec3d9 | 294 | /************************************************* |
17c76198 | 295 | * Deal with logging errors during I/O * |
059ec3d9 PH |
296 | *************************************************/ |
297 | ||
17c76198 | 298 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 299 | |
17c76198 PP |
300 | Argument: |
301 | state the current GnuTLS exim state container | |
302 | rc the GnuTLS error code, or 0 if it's a local error | |
303 | when text identifying read or write | |
304 | text local error text when ec is 0 | |
059ec3d9 | 305 | |
17c76198 | 306 | Returns: nothing |
059ec3d9 PH |
307 | */ |
308 | ||
17c76198 PP |
309 | static void |
310 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 311 | { |
17c76198 | 312 | const char *msg; |
059ec3d9 | 313 | |
17c76198 PP |
314 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
315 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
316 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
317 | else | |
318 | msg = gnutls_strerror(rc); | |
059ec3d9 | 319 | |
17c76198 PP |
320 | tls_error(when, msg, state->host); |
321 | } | |
059ec3d9 | 322 | |
059ec3d9 | 323 | |
059ec3d9 | 324 | |
059ec3d9 | 325 | |
17c76198 PP |
326 | /************************************************* |
327 | * Set various Exim expansion vars * | |
328 | *************************************************/ | |
059ec3d9 | 329 | |
e51c7be2 JH |
330 | #define exim_gnutls_cert_err(Label) \ |
331 | do \ | |
332 | { \ | |
333 | if (rc != GNUTLS_E_SUCCESS) \ | |
334 | { \ | |
335 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
336 | (Label), gnutls_strerror(rc)); \ | |
337 | return rc; \ | |
338 | } \ | |
339 | } while (0) | |
9d1c15ef JH |
340 | |
341 | static int | |
27f19eb4 | 342 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
343 | { |
344 | int rc; | |
345 | ||
346 | rc = gnutls_x509_crt_init(crtp); | |
347 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
348 | ||
349 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
350 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
351 | ||
352 | return rc; | |
353 | } | |
354 | ||
355 | #undef exim_gnutls_cert_err | |
356 | ||
357 | ||
17c76198 PP |
358 | /* We set various Exim global variables from the state, once a session has |
359 | been established. With TLS callouts, may need to change this to stack | |
360 | variables, or just re-call it with the server state after client callout | |
361 | has finished. | |
059ec3d9 | 362 | |
9d1c15ef | 363 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
364 | |
365 | Sets: | |
366 | tls_active fd | |
367 | tls_bits strength indicator | |
368 | tls_certificate_verified bool indicator | |
369 | tls_channelbinding_b64 for some SASL mechanisms | |
370 | tls_cipher a string | |
9d1c15ef | 371 | tls_peercert pointer to library internal |
17c76198 PP |
372 | tls_peerdn a string |
373 | tls_sni a (UTF-8) string | |
9d1c15ef | 374 | tls_ourcert pointer to library internal |
17c76198 PP |
375 | |
376 | Argument: | |
377 | state the relevant exim_gnutls_state_st * | |
378 | */ | |
379 | ||
380 | static void | |
9d1c15ef | 381 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 382 | { |
17c76198 | 383 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
384 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
385 | int old_pool; | |
386 | int rc; | |
387 | gnutls_datum_t channel; | |
388 | #endif | |
9d1c15ef | 389 | tls_support * tlsp = state->tlsp; |
17c76198 | 390 | |
9d1c15ef | 391 | tlsp->active = state->fd_out; |
17c76198 PP |
392 | |
393 | cipher = gnutls_cipher_get(state->session); | |
394 | /* returns size in "bytes" */ | |
9d1c15ef | 395 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 396 | |
9d1c15ef | 397 | tlsp->cipher = state->ciphersuite; |
17c76198 | 398 | |
817d9f57 | 399 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 400 | |
9d1c15ef | 401 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 402 | |
17c76198 PP |
403 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
404 | only available for use for authenticators while this TLS session is running. */ | |
405 | ||
406 | tls_channelbinding_b64 = NULL; | |
407 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
408 | channel.data = NULL; | |
409 | channel.size = 0; | |
410 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
411 | if (rc) { | |
412 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
413 | } else { | |
414 | old_pool = store_pool; | |
415 | store_pool = POOL_PERM; | |
f4d091fb | 416 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
417 | store_pool = old_pool; |
418 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
419 | } | |
420 | #endif | |
421 | ||
9d1c15ef JH |
422 | /* peercert is set in peer_status() */ |
423 | tlsp->peerdn = state->peerdn; | |
424 | tlsp->sni = state->received_sni; | |
425 | ||
426 | /* record our certificate */ | |
427 | { | |
27f19eb4 | 428 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
429 | gnutls_x509_crt_t crt; |
430 | ||
431 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
432 | } | |
059ec3d9 PH |
433 | } |
434 | ||
435 | ||
436 | ||
17c76198 | 437 | |
059ec3d9 | 438 | /************************************************* |
575643cd | 439 | * Setup up DH parameters * |
059ec3d9 PH |
440 | *************************************************/ |
441 | ||
575643cd | 442 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
443 | be re-generated every so often, depending on security policy. What we do is to |
444 | keep these parameters in a file in the spool directory. If the file does not | |
445 | exist, we generate them. This means that it is easy to cause a regeneration. | |
446 | ||
447 | The new file is written as a temporary file and renamed, so that an incomplete | |
448 | file is never present. If two processes both compute some new parameters, you | |
449 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
450 | prevent this. | |
451 | ||
059ec3d9 PH |
452 | Returns: OK/DEFER/FAIL |
453 | */ | |
454 | ||
455 | static int | |
17c76198 | 456 | init_server_dh(void) |
059ec3d9 | 457 | { |
17c76198 PP |
458 | int fd, rc; |
459 | unsigned int dh_bits; | |
27f19eb4 | 460 | gnutls_datum_t m; |
a799883d PP |
461 | uschar filename_buf[PATH_MAX]; |
462 | uschar *filename = NULL; | |
17c76198 | 463 | size_t sz; |
a799883d PP |
464 | uschar *exp_tls_dhparam; |
465 | BOOL use_file_in_spool = FALSE; | |
466 | BOOL use_fixed_file = FALSE; | |
17c76198 | 467 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 468 | |
17c76198 | 469 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 470 | |
17c76198 PP |
471 | rc = gnutls_dh_params_init(&dh_server_params); |
472 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 473 | |
a799883d PP |
474 | m.data = NULL; |
475 | m.size = 0; | |
476 | ||
477 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
478 | return DEFER; | |
479 | ||
480 | if (!exp_tls_dhparam) | |
481 | { | |
482 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
483 | m.data = US std_dh_prime_default(); | |
484 | m.size = Ustrlen(m.data); | |
485 | } | |
486 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
487 | use_file_in_spool = TRUE; | |
488 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
489 | { | |
490 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
491 | return OK; | |
492 | } | |
493 | else if (exp_tls_dhparam[0] != '/') | |
494 | { | |
495 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
496 | if (m.data == NULL) | |
497 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
498 | m.size = Ustrlen(m.data); | |
499 | } | |
500 | else | |
501 | { | |
502 | use_fixed_file = TRUE; | |
503 | filename = exp_tls_dhparam; | |
504 | } | |
505 | ||
506 | if (m.data) | |
507 | { | |
508 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
509 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
510 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
511 | return OK; | |
512 | } | |
513 | ||
af3498d6 PP |
514 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
515 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
516 | different filename and ensure we have sufficient bits. */ |
517 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
518 | if (!dh_bits) | |
519 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 520 | DEBUG(D_tls) |
b34fc30c | 521 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
522 | dh_bits); |
523 | #else | |
524 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
525 | DEBUG(D_tls) | |
526 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
527 | dh_bits); | |
528 | #endif | |
059ec3d9 | 529 | |
3375e053 PP |
530 | /* Some clients have hard-coded limits. */ |
531 | if (dh_bits > tls_dh_max_bits) | |
532 | { | |
533 | DEBUG(D_tls) | |
534 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
535 | tls_dh_max_bits); | |
536 | dh_bits = tls_dh_max_bits; | |
537 | } | |
538 | ||
a799883d PP |
539 | if (use_file_in_spool) |
540 | { | |
541 | if (!string_format(filename_buf, sizeof(filename_buf), | |
542 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
543 | return tls_error(US"overlong filename", NULL, NULL); | |
544 | filename = filename_buf; | |
545 | } | |
059ec3d9 | 546 | |
b5aea5e1 | 547 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 548 | parameters. */ |
059ec3d9 PH |
549 | |
550 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 551 | if (fd >= 0) |
059ec3d9 | 552 | { |
b5aea5e1 | 553 | struct stat statbuf; |
17c76198 PP |
554 | FILE *fp; |
555 | int saved_errno; | |
556 | ||
557 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
558 | { | |
559 | saved_errno = errno; | |
560 | (void)close(fd); | |
561 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
562 | } | |
563 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
564 | { |
565 | (void)close(fd); | |
17c76198 PP |
566 | return tls_error(US"TLS cache not a file", NULL, NULL); |
567 | } | |
568 | fp = fdopen(fd, "rb"); | |
569 | if (!fp) | |
570 | { | |
571 | saved_errno = errno; | |
572 | (void)close(fd); | |
573 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
574 | strerror(saved_errno), NULL); | |
b5aea5e1 | 575 | } |
059ec3d9 | 576 | |
b5aea5e1 PH |
577 | m.size = statbuf.st_size; |
578 | m.data = malloc(m.size); | |
579 | if (m.data == NULL) | |
17c76198 PP |
580 | { |
581 | fclose(fp); | |
582 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
583 | } | |
584 | sz = fread(m.data, m.size, 1, fp); | |
585 | if (!sz) | |
586 | { | |
587 | saved_errno = errno; | |
588 | fclose(fp); | |
589 | free(m.data); | |
590 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
591 | } | |
592 | fclose(fp); | |
b5aea5e1 | 593 | |
17c76198 | 594 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 595 | free(m.data); |
17c76198 PP |
596 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
597 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
598 | } |
599 | ||
600 | /* If the file does not exist, fall through to compute new data and cache it. | |
601 | If there was any other opening error, it is serious. */ | |
602 | ||
182ad5cf PH |
603 | else if (errno == ENOENT) |
604 | { | |
17c76198 | 605 | rc = -1; |
182ad5cf | 606 | DEBUG(D_tls) |
17c76198 | 607 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
608 | } |
609 | else | |
17c76198 PP |
610 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
611 | NULL, NULL); | |
b5aea5e1 PH |
612 | |
613 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
614 | is not useful. One particular case of this is when upgrading from an older | |
615 | release of Exim in which the data was stored in a different format. We don't | |
616 | try to be clever and support both formats; we just regenerate new data in this | |
617 | case. */ | |
618 | ||
17c76198 | 619 | if (rc < 0) |
b5aea5e1 | 620 | { |
17c76198 | 621 | uschar *temp_fn; |
201f5254 | 622 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 623 | |
17c76198 PP |
624 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
625 | return tls_error(US"Filename too long to generate replacement", | |
626 | CS filename, NULL); | |
059ec3d9 | 627 | |
17c76198 PP |
628 | temp_fn = string_copy(US "%s.XXXXXXX"); |
629 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 630 | if (fd < 0) |
17c76198 | 631 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
632 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
633 | ||
201f5254 PP |
634 | /* GnuTLS overshoots! |
635 | * If we ask for 2236, we might get 2237 or more. | |
636 | * But there's no way to ask GnuTLS how many bits there really are. | |
637 | * We can ask how many bits were used in a TLS session, but that's it! | |
638 | * The prime itself is hidden behind too much abstraction. | |
639 | * So we ask for less, and proceed on a wing and a prayer. | |
640 | * First attempt, subtracted 3 for 2233 and got 2240. | |
641 | */ | |
cae6e576 | 642 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
643 | { |
644 | dh_bits_gen = dh_bits - 10; | |
645 | DEBUG(D_tls) | |
646 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
647 | dh_bits_gen); | |
648 | } | |
649 | ||
650 | DEBUG(D_tls) | |
651 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
652 | dh_bits_gen); | |
653 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
654 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
655 | ||
656 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
657 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
658 | sample apps handle this. */ | |
659 | ||
660 | sz = 0; | |
661 | m.data = NULL; | |
662 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
663 | m.data, &sz); | |
664 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
665 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
666 | m.size = sz; | |
b5aea5e1 PH |
667 | m.data = malloc(m.size); |
668 | if (m.data == NULL) | |
17c76198 | 669 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
1f00591e | 670 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 671 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 672 | m.data, &sz); |
17c76198 PP |
673 | if (rc != GNUTLS_E_SUCCESS) |
674 | { | |
675 | free(m.data); | |
676 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
677 | } | |
1f00591e | 678 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 679 | |
17c76198 PP |
680 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
681 | if (sz != m.size) | |
682 | { | |
683 | free(m.data); | |
684 | return tls_error(US"TLS cache write D-H params failed", | |
685 | strerror(errno), NULL); | |
686 | } | |
b5aea5e1 | 687 | free(m.data); |
17c76198 PP |
688 | sz = write_to_fd_buf(fd, US"\n", 1); |
689 | if (sz != 1) | |
690 | return tls_error(US"TLS cache write D-H params final newline failed", | |
691 | strerror(errno), NULL); | |
692 | ||
693 | rc = close(fd); | |
694 | if (rc) | |
695 | return tls_error(US"TLS cache write close() failed", | |
696 | strerror(errno), NULL); | |
059ec3d9 | 697 | |
17c76198 PP |
698 | if (Urename(temp_fn, filename) < 0) |
699 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
700 | temp_fn, filename), strerror(errno), NULL); | |
059ec3d9 | 701 | |
17c76198 | 702 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
703 | } |
704 | ||
17c76198 | 705 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
706 | return OK; |
707 | } | |
708 | ||
709 | ||
710 | ||
711 | ||
23bb6982 JH |
712 | /* Create and install a selfsigned certificate, for use in server mode */ |
713 | ||
714 | static int | |
715 | tls_install_selfsign(exim_gnutls_state_st * state) | |
716 | { | |
717 | gnutls_x509_crt_t cert = NULL; | |
718 | time_t now; | |
719 | gnutls_x509_privkey_t pkey = NULL; | |
720 | const uschar * where; | |
721 | int rc; | |
722 | ||
723 | where = US"initialising pkey"; | |
724 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
725 | ||
726 | where = US"initialising cert"; | |
727 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
728 | ||
729 | where = US"generating pkey"; | |
730 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
731 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), | |
732 | 0))) /* _to_pk_bits() Since: 2.12.0 */ | |
733 | goto err; | |
734 | ||
735 | where = US"configuring cert"; | |
736 | now = 0; | |
737 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) | |
738 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
739 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
740 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
741 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
742 | ||
743 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
744 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
745 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
746 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
747 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
748 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
749 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
750 | ) | |
751 | goto err; | |
752 | ||
753 | where = US"signing cert"; | |
754 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
755 | ||
756 | where = US"installing selfsign cert"; | |
757 | /* Since: 2.4.0 */ | |
758 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
759 | goto err; | |
760 | ||
761 | rc = OK; | |
762 | ||
763 | out: | |
764 | if (cert) gnutls_x509_crt_deinit(cert); | |
765 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
766 | return rc; | |
767 | ||
768 | err: | |
769 | rc = tls_error(where, gnutls_strerror(rc), NULL); | |
770 | goto out; | |
771 | } | |
772 | ||
773 | ||
774 | ||
775 | ||
059ec3d9 | 776 | /************************************************* |
17c76198 | 777 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
778 | *************************************************/ |
779 | ||
17c76198 PP |
780 | /* Called from both server and client code, via tls_init(), and also from |
781 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
782 | ||
783 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
784 | ||
785 | The callback should not call us unless state->trigger_sni_changes is true, | |
786 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
787 | |
788 | Arguments: | |
17c76198 | 789 | state exim_gnutls_state_st * |
059ec3d9 PH |
790 | |
791 | Returns: OK/DEFER/FAIL | |
792 | */ | |
793 | ||
794 | static int | |
17c76198 | 795 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 796 | { |
1365611d | 797 | struct stat statbuf; |
059ec3d9 | 798 | int rc; |
17c76198 PP |
799 | const host_item *host = state->host; /* macro should be reconsidered? */ |
800 | uschar *saved_tls_certificate = NULL; | |
801 | uschar *saved_tls_privatekey = NULL; | |
802 | uschar *saved_tls_verify_certificates = NULL; | |
803 | uschar *saved_tls_crl = NULL; | |
804 | int cert_count; | |
805 | ||
806 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 807 | if (!host) /* server */ |
17c76198 PP |
808 | if (!state->received_sni) |
809 | { | |
d9b2312b JH |
810 | if (state->tls_certificate && |
811 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
812 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
813 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
814 | )) | |
17c76198 PP |
815 | { |
816 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
817 | state->trigger_sni_changes = TRUE; | |
818 | } | |
819 | } | |
820 | else | |
821 | { | |
1365611d | 822 | /* useful for debugging */ |
17c76198 PP |
823 | saved_tls_certificate = state->exp_tls_certificate; |
824 | saved_tls_privatekey = state->exp_tls_privatekey; | |
825 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
826 | saved_tls_crl = state->exp_tls_crl; | |
827 | } | |
059ec3d9 | 828 | |
1365611d PP |
829 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
830 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
831 | ||
17c76198 PP |
832 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
833 | state members, assuming consistent naming; and expand_check() returns | |
834 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 835 | |
17c76198 PP |
836 | /* check if we at least have a certificate, before doing expensive |
837 | D-H generation. */ | |
059ec3d9 | 838 | |
17c76198 PP |
839 | if (!expand_check_tlsvar(tls_certificate)) |
840 | return DEFER; | |
059ec3d9 | 841 | |
17c76198 | 842 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 843 | |
23bb6982 JH |
844 | if ( !state->exp_tls_certificate |
845 | || !*state->exp_tls_certificate | |
846 | ) | |
2b4a568d | 847 | if (!host) |
23bb6982 | 848 | return tls_install_selfsign(state); |
17c76198 PP |
849 | else |
850 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 851 | |
17c76198 | 852 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
853 | return DEFER; |
854 | ||
17c76198 PP |
855 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
856 | ||
857 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 858 | { |
17c76198 PP |
859 | state->tls_privatekey = state->tls_certificate; |
860 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 861 | } |
c91535f3 | 862 | |
059ec3d9 | 863 | |
17c76198 | 864 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
865 | { |
866 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
867 | state->exp_tls_certificate, state->exp_tls_privatekey); |
868 | ||
869 | if (state->received_sni) | |
23bb6982 JH |
870 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
871 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
872 | ) | |
17c76198 | 873 | { |
b34fc30c | 874 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
875 | } |
876 | else | |
877 | { | |
b34fc30c | 878 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 879 | } |
059ec3d9 | 880 | |
1365611d PP |
881 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
882 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
883 | GNUTLS_X509_FMT_PEM); | |
884 | exim_gnutls_err_check( | |
885 | string_sprintf("cert/key setup: cert=%s key=%s", | |
886 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
887 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 888 | } /* tls_certificate */ |
059ec3d9 | 889 | |
2b4a568d JH |
890 | |
891 | /* Set the OCSP stapling server info */ | |
892 | ||
f2de3a33 | 893 | #ifndef DISABLE_OCSP |
2b4a568d JH |
894 | if ( !host /* server */ |
895 | && tls_ocsp_file | |
896 | ) | |
897 | { | |
9196d5bf JH |
898 | if (gnutls_buggy_ocsp) |
899 | { | |
900 | DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
901 | } | |
902 | else | |
903 | { | |
904 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", | |
905 | &state->exp_tls_ocsp_file)) | |
906 | return DEFER; | |
2b4a568d | 907 | |
9196d5bf JH |
908 | /* Use the full callback method for stapling just to get observability. |
909 | More efficient would be to read the file once only, if it never changed | |
910 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
44662487 | 911 | |
9196d5bf JH |
912 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, |
913 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 914 | |
9196d5bf JH |
915 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file); |
916 | } | |
2b4a568d JH |
917 | } |
918 | #endif | |
919 | ||
920 | ||
059ec3d9 PH |
921 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
922 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
923 | error message is provided. However, if we just refrain from setting anything up | |
924 | in that case, certificate verification fails, which seems to be the correct | |
925 | behaviour. */ | |
926 | ||
610ff438 | 927 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 928 | { |
17c76198 | 929 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 930 | return DEFER; |
610ff438 JH |
931 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
932 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
933 | state->exp_tls_verify_certificates = NULL; | |
934 | #endif | |
17c76198 PP |
935 | if (state->tls_crl && *state->tls_crl) |
936 | if (!expand_check_tlsvar(tls_crl)) | |
937 | return DEFER; | |
059ec3d9 | 938 | |
1365611d PP |
939 | if (!(state->exp_tls_verify_certificates && |
940 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
941 | { |
942 | DEBUG(D_tls) | |
1365611d PP |
943 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
944 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 945 | return OK; |
b34fc30c | 946 | } |
1365611d | 947 | } |
83e2f8a2 PP |
948 | else |
949 | { | |
950 | DEBUG(D_tls) | |
951 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
952 | return OK; | |
953 | } | |
17c76198 | 954 | |
cb1d7830 JH |
955 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
956 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
957 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
958 | else | |
959 | #endif | |
1365611d | 960 | { |
cb1d7830 JH |
961 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
962 | { | |
963 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
964 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
965 | strerror(errno)); | |
966 | return DEFER; | |
967 | } | |
17c76198 | 968 | |
a7fec7a7 | 969 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
970 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
971 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
972 | other weirdness. The thing we really want to check is that it's not a | |
973 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 974 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
975 | if (S_ISDIR(statbuf.st_mode)) |
976 | { | |
977 | DEBUG(D_tls) | |
978 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
979 | state->exp_tls_verify_certificates); | |
980 | log_write(0, LOG_MAIN|LOG_PANIC, | |
981 | "tls_verify_certificates \"%s\" is a directory", | |
982 | state->exp_tls_verify_certificates); | |
983 | return DEFER; | |
984 | } | |
a7fec7a7 | 985 | #endif |
059ec3d9 | 986 | |
cb1d7830 JH |
987 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
988 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 989 | |
cb1d7830 JH |
990 | if (statbuf.st_size == 0) |
991 | { | |
992 | DEBUG(D_tls) | |
993 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
994 | return OK; | |
995 | } | |
059ec3d9 | 996 | |
cb1d7830 | 997 | cert_count = |
a7fec7a7 JH |
998 | |
999 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1000 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1001 | ? | |
1002 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1003 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1004 | : | |
a7fec7a7 | 1005 | #endif |
cb1d7830 JH |
1006 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1007 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1008 | } | |
a7fec7a7 | 1009 | |
1365611d PP |
1010 | if (cert_count < 0) |
1011 | { | |
1012 | rc = cert_count; | |
cb1d7830 | 1013 | exim_gnutls_err_check(US"setting certificate trust"); |
1365611d PP |
1014 | } |
1015 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1016 | |
5c8cda3a PP |
1017 | if (state->tls_crl && *state->tls_crl && |
1018 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1019 | { |
5c8cda3a PP |
1020 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1021 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1022 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1023 | if (cert_count < 0) | |
1365611d | 1024 | { |
5c8cda3a | 1025 | rc = cert_count; |
1365611d PP |
1026 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
1027 | } | |
5c8cda3a | 1028 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1029 | } |
059ec3d9 | 1030 | |
059ec3d9 PH |
1031 | return OK; |
1032 | } | |
1033 | ||
1034 | ||
1035 | ||
1036 | ||
1365611d PP |
1037 | /************************************************* |
1038 | * Set X.509 state variables * | |
1039 | *************************************************/ | |
1040 | ||
1041 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1042 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1043 | structure. Which means various other non-re-expanded pieces of state | |
1044 | need to be re-set in the new struct, so the setting logic is pulled | |
1045 | out to this. | |
1046 | ||
1047 | Arguments: | |
1048 | state exim_gnutls_state_st * | |
1049 | ||
1050 | Returns: OK/DEFER/FAIL | |
1051 | */ | |
1052 | ||
1053 | static int | |
1054 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
1055 | { | |
1056 | int rc; | |
1057 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1058 | ||
1059 | /* Create D-H parameters, or read them from the cache file. This function does | |
1060 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1061 | client-side params. */ | |
1062 | ||
1063 | if (!state->host) | |
1064 | { | |
1065 | if (!dh_server_params) | |
1066 | { | |
1067 | rc = init_server_dh(); | |
1068 | if (rc != OK) return rc; | |
1069 | } | |
1070 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1071 | } | |
1072 | ||
1073 | /* Link the credentials to the session. */ | |
1074 | ||
1075 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
1076 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
1077 | ||
1078 | return OK; | |
1079 | } | |
1080 | ||
059ec3d9 | 1081 | /************************************************* |
17c76198 | 1082 | * Initialize for GnuTLS * |
059ec3d9 PH |
1083 | *************************************************/ |
1084 | ||
9196d5bf | 1085 | |
4fb7df6d JH |
1086 | #ifndef DISABLE_OCSP |
1087 | ||
9196d5bf JH |
1088 | static BOOL |
1089 | tls_is_buggy_ocsp(void) | |
1090 | { | |
1091 | const uschar * s; | |
1092 | uschar maj, mid, mic; | |
1093 | ||
1094 | s = CUS gnutls_check_version(NULL); | |
1095 | maj = atoi(CCS s); | |
1096 | if (maj == 3) | |
1097 | { | |
1098 | while (*s && *s != '.') s++; | |
1099 | mid = atoi(CCS ++s); | |
1100 | if (mid <= 2) | |
1101 | return TRUE; | |
1102 | else if (mid >= 5) | |
1103 | return FALSE; | |
1104 | else | |
1105 | { | |
1106 | while (*s && *s != '.') s++; | |
1107 | mic = atoi(CCS ++s); | |
1108 | return mic <= (mid == 3 ? 16 : 3); | |
1109 | } | |
1110 | } | |
1111 | return FALSE; | |
1112 | } | |
1113 | ||
4fb7df6d | 1114 | #endif |
9196d5bf JH |
1115 | |
1116 | ||
17c76198 PP |
1117 | /* Called from both server and client code. In the case of a server, errors |
1118 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1119 | |
1120 | Arguments: | |
17c76198 PP |
1121 | host connected host, if client; NULL if server |
1122 | certificate certificate file | |
1123 | privatekey private key file | |
1124 | sni TLS SNI to send, sometimes when client; else NULL | |
1125 | cas CA certs file | |
1126 | crl CRL file | |
1127 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1128 | caller_state returned state-info structure |
059ec3d9 | 1129 | |
17c76198 | 1130 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1131 | */ |
1132 | ||
17c76198 PP |
1133 | static int |
1134 | tls_init( | |
1135 | const host_item *host, | |
1136 | const uschar *certificate, | |
1137 | const uschar *privatekey, | |
1138 | const uschar *sni, | |
1139 | const uschar *cas, | |
1140 | const uschar *crl, | |
1141 | const uschar *require_ciphers, | |
1142 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 1143 | { |
17c76198 PP |
1144 | exim_gnutls_state_st *state; |
1145 | int rc; | |
1146 | size_t sz; | |
1147 | const char *errpos; | |
1148 | uschar *p; | |
1149 | BOOL want_default_priorities; | |
1150 | ||
1151 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1152 | { |
17c76198 PP |
1153 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1154 | ||
a5f239e4 PP |
1155 | #ifdef HAVE_GNUTLS_PKCS11 |
1156 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1157 | which loads modules from a config file, which sounds good and may be wanted | |
1158 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1159 | environment variables are used and so breaks for users calling mailq. | |
1160 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1161 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1162 | { |
1163 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1164 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1165 | } | |
1166 | #endif | |
1167 | ||
17c76198 PP |
1168 | rc = gnutls_global_init(); |
1169 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1170 | ||
1171 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1172 | DEBUG(D_tls) | |
059ec3d9 | 1173 | { |
17c76198 PP |
1174 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1175 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1176 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1177 | } |
17c76198 PP |
1178 | #endif |
1179 | ||
4fb7df6d JH |
1180 | #ifndef DISABLE_OCSP |
1181 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1182 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1183 | #endif |
9196d5bf | 1184 | |
17c76198 | 1185 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1186 | } |
059ec3d9 | 1187 | |
17c76198 PP |
1188 | if (host) |
1189 | { | |
1190 | state = &state_client; | |
1191 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1192 | state->tlsp = &tls_out; |
17c76198 PP |
1193 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1194 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1195 | } | |
1196 | else | |
1197 | { | |
1198 | state = &state_server; | |
1199 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1200 | state->tlsp = &tls_in; |
17c76198 PP |
1201 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1202 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1203 | } | |
1204 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1205 | |
17c76198 | 1206 | state->host = host; |
059ec3d9 | 1207 | |
17c76198 PP |
1208 | state->tls_certificate = certificate; |
1209 | state->tls_privatekey = privatekey; | |
5779e6aa | 1210 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1211 | state->tls_sni = sni; |
1212 | state->tls_verify_certificates = cas; | |
1213 | state->tls_crl = crl; | |
059ec3d9 | 1214 | |
17c76198 PP |
1215 | /* This handles the variables that might get re-expanded after TLS SNI; |
1216 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1217 | |
17c76198 PP |
1218 | DEBUG(D_tls) |
1219 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
1220 | rc = tls_expand_session_files(state); | |
1221 | if (rc != OK) return rc; | |
059ec3d9 | 1222 | |
1365611d PP |
1223 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1224 | requires a new structure afterwards. */ | |
83da1223 | 1225 | |
1365611d PP |
1226 | rc = tls_set_remaining_x509(state); |
1227 | if (rc != OK) return rc; | |
83da1223 | 1228 | |
17c76198 PP |
1229 | /* set SNI in client, only */ |
1230 | if (host) | |
1231 | { | |
0df4ab80 | 1232 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni)) |
17c76198 | 1233 | return DEFER; |
0df4ab80 | 1234 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1235 | { |
1236 | DEBUG(D_tls) | |
0df4ab80 JH |
1237 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1238 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1239 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1240 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
17c76198 PP |
1241 | exim_gnutls_err_check(US"gnutls_server_name_set"); |
1242 | } | |
1243 | } | |
1244 | else if (state->tls_sni) | |
1245 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1246 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1247 | |
17c76198 | 1248 | /* This is the priority string support, |
42bfef1e | 1249 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1250 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1251 | This was backwards incompatible, but means Exim no longer needs to track | |
1252 | all algorithms and provide string forms for them. */ | |
83da1223 | 1253 | |
17c76198 | 1254 | want_default_priorities = TRUE; |
83da1223 | 1255 | |
17c76198 | 1256 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1257 | { |
17c76198 PP |
1258 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1259 | return DEFER; | |
1260 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1261 | { |
17c76198 PP |
1262 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1263 | state->exp_tls_require_ciphers); | |
1264 | ||
1265 | rc = gnutls_priority_init(&state->priority_cache, | |
1266 | CS state->exp_tls_require_ciphers, &errpos); | |
1267 | want_default_priorities = FALSE; | |
1268 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1269 | } |
1270 | } | |
17c76198 PP |
1271 | if (want_default_priorities) |
1272 | { | |
83e2f8a2 PP |
1273 | DEBUG(D_tls) |
1274 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1275 | exim_default_gnutls_priority); | |
17c76198 PP |
1276 | rc = gnutls_priority_init(&state->priority_cache, |
1277 | exim_default_gnutls_priority, &errpos); | |
1278 | p = US exim_default_gnutls_priority; | |
1279 | } | |
83da1223 | 1280 | |
17c76198 PP |
1281 | exim_gnutls_err_check(string_sprintf( |
1282 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1283 | p, errpos - CS p, errpos)); | |
1284 | ||
1285 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1286 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1287 | ||
1288 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1289 | ||
1290 | /* Reduce security in favour of increased compatibility, if the admin | |
1291 | decides to make that trade-off. */ | |
1292 | if (gnutls_compat_mode) | |
83da1223 | 1293 | { |
17c76198 PP |
1294 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1295 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1296 | gnutls_session_enable_compatibility_mode(state->session); | |
1297 | #else | |
1298 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1299 | #endif | |
83da1223 PH |
1300 | } |
1301 | ||
17c76198 | 1302 | *caller_state = state; |
17c76198 | 1303 | return OK; |
83da1223 PH |
1304 | } |
1305 | ||
1306 | ||
1307 | ||
059ec3d9 | 1308 | /************************************************* |
17c76198 | 1309 | * Extract peer information * |
059ec3d9 PH |
1310 | *************************************************/ |
1311 | ||
17c76198 | 1312 | /* Called from both server and client code. |
4fe99a6c PP |
1313 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1314 | and we use that to detect double-calls. | |
059ec3d9 | 1315 | |
75fe387d PP |
1316 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1317 | for logging in the server side, but for the client side, we log after teardown | |
1318 | in src/deliver.c. While the session is up, we can twist about states and | |
1319 | repoint tls_* globals, but those variables used for logging or other variable | |
1320 | expansion that happens _after_ delivery need to have a longer life-time. | |
1321 | ||
1322 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1323 | doing this more than once per generation of a state context. We set them in | |
1324 | the state context, and repoint tls_* to them. After the state goes away, the | |
1325 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1326 | ||
1327 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1328 | don't apply. | |
1329 | ||
059ec3d9 | 1330 | Arguments: |
17c76198 | 1331 | state exim_gnutls_state_st * |
059ec3d9 | 1332 | |
17c76198 | 1333 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1334 | */ |
1335 | ||
17c76198 PP |
1336 | static int |
1337 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1338 | { |
75fe387d | 1339 | uschar cipherbuf[256]; |
27f19eb4 | 1340 | const gnutls_datum_t *cert_list; |
75fe387d | 1341 | int old_pool, rc; |
17c76198 | 1342 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1343 | gnutls_protocol_t protocol; |
1344 | gnutls_cipher_algorithm_t cipher; | |
1345 | gnutls_kx_algorithm_t kx; | |
1346 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1347 | gnutls_certificate_type_t ct; |
1348 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1349 | uschar *p, *dn_buf; |
17c76198 | 1350 | size_t sz; |
059ec3d9 | 1351 | |
4fe99a6c | 1352 | if (state->have_set_peerdn) |
17c76198 | 1353 | return OK; |
4fe99a6c | 1354 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1355 | |
4fe99a6c | 1356 | state->peerdn = NULL; |
059ec3d9 | 1357 | |
4fe99a6c PP |
1358 | /* tls_cipher */ |
1359 | cipher = gnutls_cipher_get(state->session); | |
1360 | protocol = gnutls_protocol_get_version(state->session); | |
1361 | mac = gnutls_mac_get(state->session); | |
1362 | kx = gnutls_kx_get(state->session); | |
1363 | ||
75fe387d | 1364 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1365 | "%s:%s:%d", |
1366 | gnutls_protocol_get_name(protocol), | |
1367 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1368 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1369 | ||
1370 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1371 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1372 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1373 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1374 | if (isspace(*p)) |
1375 | *p = '-'; | |
75fe387d PP |
1376 | old_pool = store_pool; |
1377 | store_pool = POOL_PERM; | |
1378 | state->ciphersuite = string_copy(cipherbuf); | |
1379 | store_pool = old_pool; | |
817d9f57 | 1380 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1381 | |
1382 | /* tls_peerdn */ | |
17c76198 | 1383 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1384 | |
17c76198 PP |
1385 | if (cert_list == NULL || cert_list_size == 0) |
1386 | { | |
17c76198 PP |
1387 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1388 | cert_list, cert_list_size); | |
e51c7be2 | 1389 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1390 | return tls_error(US"certificate verification failed", |
1391 | "no certificate received from peer", state->host); | |
1392 | return OK; | |
1393 | } | |
059ec3d9 | 1394 | |
17c76198 PP |
1395 | ct = gnutls_certificate_type_get(state->session); |
1396 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1397 | { |
17c76198 | 1398 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1399 | DEBUG(D_tls) |
1400 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1401 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1402 | return tls_error(US"certificate verification not possible, unhandled type", |
1403 | ctn, state->host); | |
1404 | return OK; | |
83da1223 | 1405 | } |
059ec3d9 | 1406 | |
e51c7be2 JH |
1407 | #define exim_gnutls_peer_err(Label) \ |
1408 | do { \ | |
1409 | if (rc != GNUTLS_E_SUCCESS) \ | |
1410 | { \ | |
1411 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1412 | (Label), gnutls_strerror(rc)); \ | |
1413 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
1414 | return tls_error((Label), gnutls_strerror(rc), state->host); \ | |
1415 | return OK; \ | |
1416 | } \ | |
1417 | } while (0) | |
17c76198 | 1418 | |
9d1c15ef JH |
1419 | rc = import_cert(&cert_list[0], &crt); |
1420 | exim_gnutls_peer_err(US"cert 0"); | |
1421 | ||
1422 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1423 | |
17c76198 PP |
1424 | sz = 0; |
1425 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1426 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1427 | { |
17c76198 PP |
1428 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1429 | return FAIL; /* should not happen */ | |
059ec3d9 | 1430 | } |
17c76198 PP |
1431 | dn_buf = store_get_perm(sz); |
1432 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1433 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1434 | |
17c76198 PP |
1435 | state->peerdn = dn_buf; |
1436 | ||
1437 | return OK; | |
1438 | #undef exim_gnutls_peer_err | |
1439 | } | |
059ec3d9 | 1440 | |
059ec3d9 | 1441 | |
059ec3d9 | 1442 | |
059ec3d9 | 1443 | |
17c76198 PP |
1444 | /************************************************* |
1445 | * Verify peer certificate * | |
1446 | *************************************************/ | |
059ec3d9 | 1447 | |
17c76198 PP |
1448 | /* Called from both server and client code. |
1449 | *Should* be using a callback registered with | |
1450 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1451 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1452 | |
17c76198 PP |
1453 | Arguments: |
1454 | state exim_gnutls_state_st * | |
1455 | error where to put an error message | |
059ec3d9 | 1456 | |
17c76198 PP |
1457 | Returns: |
1458 | FALSE if the session should be rejected | |
1459 | TRUE if the cert is okay or we just don't care | |
1460 | */ | |
059ec3d9 | 1461 | |
17c76198 PP |
1462 | static BOOL |
1463 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1464 | { | |
1465 | int rc; | |
1466 | unsigned int verify; | |
1467 | ||
1468 | *error = NULL; | |
1469 | ||
0a92f87f | 1470 | if ((rc = peer_status(state)) != OK) |
e6060e2c | 1471 | { |
17c76198 | 1472 | verify = GNUTLS_CERT_INVALID; |
0a92f87f | 1473 | *error = "certificate not supplied"; |
17c76198 PP |
1474 | } |
1475 | else | |
17c76198 | 1476 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1477 | |
17c76198 PP |
1478 | /* Handle the result of verification. INVALID seems to be set as well |
1479 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1480 | |
e51c7be2 JH |
1481 | if (rc < 0 || |
1482 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1483 | ) | |
17c76198 PP |
1484 | { |
1485 | state->peer_cert_verified = FALSE; | |
0a92f87f JH |
1486 | if (!*error) |
1487 | *error = verify & GNUTLS_CERT_REVOKED | |
1488 | ? "certificate revoked" : "certificate invalid"; | |
059ec3d9 | 1489 | |
17c76198 | 1490 | DEBUG(D_tls) |
e51c7be2 | 1491 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
4fe99a6c | 1492 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1493 | |
e51c7be2 | 1494 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1495 | { |
e51c7be2 JH |
1496 | gnutls_alert_send(state->session, |
1497 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1498 | return FALSE; |
1499 | } | |
1500 | DEBUG(D_tls) | |
4789da3a | 1501 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1502 | } |
e51c7be2 | 1503 | |
17c76198 PP |
1504 | else |
1505 | { | |
aa2a70ba | 1506 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1507 | { |
1508 | int sep = 0; | |
55414b25 | 1509 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 JH |
1510 | uschar * name; |
1511 | while (name = string_nextinlist(&list, &sep, NULL, 0)) | |
1512 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) | |
1513 | break; | |
1514 | if (!name) | |
1515 | { | |
1516 | DEBUG(D_tls) | |
1517 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba JH |
1518 | if (state->verify_requirement >= VERIFY_REQUIRED) |
1519 | { | |
1520 | gnutls_alert_send(state->session, | |
1521 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1522 | return FALSE; | |
1523 | } | |
1524 | return TRUE; | |
e51c7be2 JH |
1525 | } |
1526 | } | |
17c76198 | 1527 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1528 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1529 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1530 | } |
059ec3d9 | 1531 | |
817d9f57 | 1532 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1533 | |
17c76198 PP |
1534 | return TRUE; |
1535 | } | |
059ec3d9 | 1536 | |
17c76198 PP |
1537 | |
1538 | ||
1539 | ||
1540 | /* ------------------------------------------------------------------------ */ | |
1541 | /* Callbacks */ | |
1542 | ||
1543 | /* Logging function which can be registered with | |
1544 | * gnutls_global_set_log_function() | |
1545 | * gnutls_global_set_log_level() 0..9 | |
1546 | */ | |
af3498d6 | 1547 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1548 | static void |
17c76198 | 1549 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1550 | { |
8c79eebf PP |
1551 | size_t len = strlen(message); |
1552 | if (len < 1) | |
1553 | { | |
1554 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1555 | return; | |
1556 | } | |
1557 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1558 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1559 | } |
af3498d6 | 1560 | #endif |
059ec3d9 | 1561 | |
059ec3d9 | 1562 | |
17c76198 PP |
1563 | /* Called after client hello, should handle SNI work. |
1564 | This will always set tls_sni (state->received_sni) if available, | |
1565 | and may trigger presenting different certificates, | |
1566 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1567 | |
17c76198 PP |
1568 | Should be registered with |
1569 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1570 | |
17c76198 PP |
1571 | "This callback must return 0 on success or a gnutls error code to terminate the |
1572 | handshake.". | |
059ec3d9 | 1573 | |
17c76198 PP |
1574 | For inability to get SNI information, we return 0. |
1575 | We only return non-zero if re-setup failed. | |
817d9f57 | 1576 | Only used for server-side TLS. |
17c76198 | 1577 | */ |
44bbabb5 | 1578 | |
17c76198 PP |
1579 | static int |
1580 | exim_sni_handling_cb(gnutls_session_t session) | |
1581 | { | |
1582 | char sni_name[MAX_HOST_LEN]; | |
1583 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1584 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1585 | unsigned int sni_type; |
1586 | int rc, old_pool; | |
1587 | ||
1588 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1589 | if (rc != GNUTLS_E_SUCCESS) |
1590 | { | |
1591 | DEBUG(D_tls) { | |
1592 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1593 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1594 | else | |
1595 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1596 | gnutls_strerror(rc), rc); | |
1597 | }; | |
1598 | return 0; | |
1599 | } | |
1600 | ||
17c76198 PP |
1601 | if (sni_type != GNUTLS_NAME_DNS) |
1602 | { | |
1603 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1604 | return 0; | |
1605 | } | |
44bbabb5 | 1606 | |
17c76198 PP |
1607 | /* We now have a UTF-8 string in sni_name */ |
1608 | old_pool = store_pool; | |
1609 | store_pool = POOL_PERM; | |
1610 | state->received_sni = string_copyn(US sni_name, data_len); | |
1611 | store_pool = old_pool; | |
1612 | ||
1613 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1614 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1615 | |
1616 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1617 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1618 | ||
1619 | if (!state->trigger_sni_changes) | |
1620 | return 0; | |
1621 | ||
1622 | rc = tls_expand_session_files(state); | |
1623 | if (rc != OK) | |
1624 | { | |
1625 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1626 | been offered. The best we can do now is abort. */ | |
1627 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1628 | } | |
1629 | ||
1365611d PP |
1630 | rc = tls_set_remaining_x509(state); |
1631 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1632 | ||
1633 | return 0; | |
059ec3d9 PH |
1634 | } |
1635 | ||
1636 | ||
1637 | ||
f2de3a33 | 1638 | #ifndef DISABLE_OCSP |
44662487 JH |
1639 | |
1640 | static int | |
1641 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1642 | gnutls_datum_t * ocsp_response) | |
1643 | { | |
1644 | int ret; | |
1645 | ||
44662487 JH |
1646 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1647 | { | |
1648 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
1649 | (char *)ptr); | |
018058b2 | 1650 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1651 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1652 | } | |
1653 | ||
018058b2 | 1654 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1655 | return 0; |
1656 | } | |
1657 | ||
1658 | #endif | |
1659 | ||
1660 | ||
0cbf2b82 | 1661 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1662 | /* |
1663 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1664 | for an exim TLS connection (either direction), raising a tls:cert event |
1665 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1666 | can deny verification. |
1667 | ||
1668 | Return 0 for the handshake to continue or non-zero to terminate. | |
1669 | */ | |
1670 | ||
1671 | static int | |
723fe533 | 1672 | verify_cb(gnutls_session_t session) |
a7538db1 | 1673 | { |
27f19eb4 | 1674 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1675 | unsigned int cert_list_size = 0; |
1676 | gnutls_x509_crt_t crt; | |
1677 | int rc; | |
b30275b8 | 1678 | uschar * yield; |
a7538db1 JH |
1679 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1680 | ||
1681 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1682 | if (cert_list) | |
1683 | while (cert_list_size--) | |
1684 | { | |
1685 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1686 | if (rc != GNUTLS_E_SUCCESS) | |
1687 | { | |
1688 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1689 | cert_list_size, gnutls_strerror(rc)); | |
1690 | break; | |
1691 | } | |
1692 | ||
1693 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1694 | if ((yield = event_raise(state->event_action, |
1695 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1696 | { |
1697 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1698 | "SSL verify denied by event-action: depth=%d: %s", |
1699 | cert_list_size, yield); | |
a7538db1 JH |
1700 | return 1; /* reject */ |
1701 | } | |
1702 | state->tlsp->peercert = NULL; | |
1703 | } | |
1704 | ||
1705 | return 0; | |
1706 | } | |
1707 | ||
1708 | #endif | |
44662487 JH |
1709 | |
1710 | ||
17c76198 PP |
1711 | |
1712 | /* ------------------------------------------------------------------------ */ | |
1713 | /* Exported functions */ | |
1714 | ||
1715 | ||
1716 | ||
1717 | ||
059ec3d9 PH |
1718 | /************************************************* |
1719 | * Start a TLS session in a server * | |
1720 | *************************************************/ | |
1721 | ||
1722 | /* This is called when Exim is running as a server, after having received | |
1723 | the STARTTLS command. It must respond to that command, and then negotiate | |
1724 | a TLS session. | |
1725 | ||
1726 | Arguments: | |
83da1223 | 1727 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1728 | |
1729 | Returns: OK on success | |
1730 | DEFER for errors before the start of the negotiation | |
1731 | FAIL for errors during the negotation; the server can't | |
1732 | continue running. | |
1733 | */ | |
1734 | ||
1735 | int | |
17c76198 | 1736 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1737 | { |
1738 | int rc; | |
7199e1ee | 1739 | const char *error; |
17c76198 | 1740 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1741 | |
1742 | /* Check for previous activation */ | |
817d9f57 | 1743 | if (tls_in.active >= 0) |
059ec3d9 | 1744 | { |
17c76198 | 1745 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1746 | smtp_printf("554 Already in TLS\r\n"); |
1747 | return FAIL; | |
1748 | } | |
1749 | ||
1750 | /* Initialize the library. If it fails, it will already have logged the error | |
1751 | and sent an SMTP response. */ | |
1752 | ||
17c76198 | 1753 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1754 | |
17c76198 PP |
1755 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1756 | NULL, tls_verify_certificates, tls_crl, | |
1757 | require_ciphers, &state); | |
059ec3d9 PH |
1758 | if (rc != OK) return rc; |
1759 | ||
059ec3d9 PH |
1760 | /* If this is a host for which certificate verification is mandatory or |
1761 | optional, set up appropriately. */ | |
1762 | ||
059ec3d9 | 1763 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1764 | { |
e51c7be2 JH |
1765 | DEBUG(D_tls) |
1766 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1767 | state->verify_requirement = VERIFY_REQUIRED; |
1768 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1769 | } | |
059ec3d9 | 1770 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1771 | { |
e51c7be2 JH |
1772 | DEBUG(D_tls) |
1773 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1774 | state->verify_requirement = VERIFY_OPTIONAL; |
1775 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1776 | } | |
1777 | else | |
1778 | { | |
e51c7be2 JH |
1779 | DEBUG(D_tls) |
1780 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1781 | state->verify_requirement = VERIFY_NONE; |
1782 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1783 | } | |
059ec3d9 | 1784 | |
0cbf2b82 | 1785 | #ifndef DISABLE_EVENT |
723fe533 JH |
1786 | if (event_action) |
1787 | { | |
1788 | state->event_action = event_action; | |
1789 | gnutls_session_set_ptr(state->session, state); | |
1790 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
1791 | } | |
1792 | #endif | |
1793 | ||
17c76198 PP |
1794 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1795 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1796 | |
17c76198 PP |
1797 | gnutls_handshake_set_post_client_hello_function(state->session, |
1798 | exim_sni_handling_cb); | |
059ec3d9 PH |
1799 | |
1800 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1801 | on connection, where outputting anything now upsets the clients and tends to | |
1802 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1803 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1804 | mode, the fflush() happens when smtp_getc() is called. */ | |
1805 | ||
817d9f57 | 1806 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1807 | { |
1808 | smtp_printf("220 TLS go ahead\r\n"); | |
9d1c15ef | 1809 | fflush(smtp_out); |
059ec3d9 PH |
1810 | } |
1811 | ||
1812 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1813 | that the GnuTLS library doesn't. */ | |
1814 | ||
17c76198 | 1815 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
1816 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
1817 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
1818 | state->fd_in = fileno(smtp_in); |
1819 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1820 | |
1821 | sigalrm_seen = FALSE; | |
1822 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 PP |
1823 | do |
1824 | { | |
1825 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1826 | } while ((rc == GNUTLS_E_AGAIN) || |
1827 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1828 | alarm(0); |
1829 | ||
17c76198 | 1830 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1831 | { |
17c76198 PP |
1832 | tls_error(US"gnutls_handshake", |
1833 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
059ec3d9 PH |
1834 | /* It seems that, except in the case of a timeout, we have to close the |
1835 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1836 | until the server times out. */ | |
1837 | ||
1838 | if (!sigalrm_seen) | |
1839 | { | |
f1e894f3 PH |
1840 | (void)fclose(smtp_out); |
1841 | (void)fclose(smtp_in); | |
059ec3d9 PH |
1842 | } |
1843 | ||
1844 | return FAIL; | |
1845 | } | |
1846 | ||
1847 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1848 | ||
17c76198 PP |
1849 | /* Verify after the fact */ |
1850 | ||
9d1c15ef JH |
1851 | if ( state->verify_requirement != VERIFY_NONE |
1852 | && !verify_certificate(state, &error)) | |
059ec3d9 | 1853 | { |
9d1c15ef | 1854 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1855 | { |
9d1c15ef JH |
1856 | tls_error(US"certificate verification failed", error, NULL); |
1857 | return FAIL; | |
17c76198 | 1858 | } |
9d1c15ef JH |
1859 | DEBUG(D_tls) |
1860 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1861 | error); | |
059ec3d9 PH |
1862 | } |
1863 | ||
17c76198 PP |
1864 | /* Figure out peer DN, and if authenticated, etc. */ |
1865 | ||
1866 | rc = peer_status(state); | |
1867 | if (rc != OK) return rc; | |
1868 | ||
1869 | /* Sets various Exim expansion variables; always safe within server */ | |
1870 | ||
9d1c15ef | 1871 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1872 | |
1873 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1874 | and initialize appropriately. */ | |
1875 | ||
17c76198 | 1876 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1877 | |
1878 | receive_getc = tls_getc; | |
1879 | receive_ungetc = tls_ungetc; | |
1880 | receive_feof = tls_feof; | |
1881 | receive_ferror = tls_ferror; | |
58eb016e | 1882 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1883 | |
059ec3d9 PH |
1884 | return OK; |
1885 | } | |
1886 | ||
1887 | ||
1888 | ||
1889 | ||
aa2a70ba JH |
1890 | static void |
1891 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
1892 | smtp_transport_options_block * ob) | |
1893 | { | |
5130845b | 1894 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 1895 | { |
4af0d74a | 1896 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 1897 | #ifdef SUPPORT_I18N |
4af0d74a JH |
1898 | string_domain_utf8_to_alabel(host->name, NULL); |
1899 | #else | |
1900 | host->name; | |
1901 | #endif | |
aa2a70ba JH |
1902 | DEBUG(D_tls) |
1903 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
1904 | state->exp_tls_verify_cert_hostnames); | |
1905 | } | |
1906 | } | |
aa2a70ba JH |
1907 | |
1908 | ||
059ec3d9 PH |
1909 | /************************************************* |
1910 | * Start a TLS session in a client * | |
1911 | *************************************************/ | |
1912 | ||
1913 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1914 | ||
1915 | Arguments: | |
1916 | fd the fd of the connection | |
1917 | host connected host (for messages) | |
83da1223 | 1918 | addr the first address (not used) |
a7538db1 | 1919 | tb transport (always smtp) |
059ec3d9 PH |
1920 | |
1921 | Returns: OK/DEFER/FAIL (because using common functions), | |
1922 | but for a client, DEFER and FAIL have the same meaning | |
1923 | */ | |
1924 | ||
1925 | int | |
17c76198 | 1926 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1927 | address_item *addr ARG_UNUSED, |
0e66b3b6 JH |
1928 | transport_instance *tb |
1929 | #ifdef EXPERIMENTAL_DANE | |
b2ba1b4c | 1930 | , dns_answer * unused_tlsa_dnsa |
0e66b3b6 JH |
1931 | #endif |
1932 | ) | |
059ec3d9 | 1933 | { |
a7538db1 JH |
1934 | smtp_transport_options_block *ob = |
1935 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 1936 | int rc; |
17c76198 PP |
1937 | const char *error; |
1938 | exim_gnutls_state_st *state = NULL; | |
f2de3a33 | 1939 | #ifndef DISABLE_OCSP |
5130845b JH |
1940 | BOOL require_ocsp = |
1941 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 1942 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 1943 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 1944 | #endif |
059ec3d9 | 1945 | |
17c76198 | 1946 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1947 | |
65867078 JH |
1948 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
1949 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
1950 | ob->tls_require_ciphers, &state)) != OK) | |
2b4a568d | 1951 | return rc; |
059ec3d9 | 1952 | |
54c90be1 | 1953 | { |
65867078 JH |
1954 | int dh_min_bits = ob->tls_dh_min_bits; |
1955 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
1956 | { | |
1957 | DEBUG(D_tls) | |
1958 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
1959 | " clamping %d up to %d\n", | |
1960 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1961 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1962 | } | |
54c90be1 | 1963 | |
65867078 JH |
1964 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
1965 | " acceptable bits to %d\n", | |
1966 | dh_min_bits); | |
1967 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
1968 | } | |
83da1223 | 1969 | |
94431adb | 1970 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
1971 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
1972 | the specified host patterns if one of them is defined */ | |
1973 | ||
aa2a70ba JH |
1974 | if ( ( state->exp_tls_verify_certificates |
1975 | && !ob->tls_verify_hosts | |
610ff438 | 1976 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) |
aa2a70ba | 1977 | ) |
5130845b | 1978 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK |
2b4a568d | 1979 | ) |
17c76198 | 1980 | { |
aa2a70ba | 1981 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
1982 | DEBUG(D_tls) |
1983 | debug_printf("TLS: server certificate verification required.\n"); | |
1984 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
1985 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
1986 | } | |
5130845b | 1987 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 1988 | { |
aa2a70ba | 1989 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
1990 | DEBUG(D_tls) |
1991 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 1992 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
1993 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
1994 | } | |
1995 | else | |
1996 | { | |
e51c7be2 JH |
1997 | DEBUG(D_tls) |
1998 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
1999 | state->verify_requirement = VERIFY_NONE; |
2000 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2001 | } |
059ec3d9 | 2002 | |
f2de3a33 JH |
2003 | #ifndef DISABLE_OCSP |
2004 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2005 | if (request_ocsp) |
9d1c15ef JH |
2006 | { |
2007 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2008 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2009 | NULL, 0, NULL)) != OK) | |
9d1c15ef JH |
2010 | return tls_error(US"cert-status-req", |
2011 | gnutls_strerror(rc), state->host); | |
44662487 | 2012 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2013 | } |
2b4a568d JH |
2014 | #endif |
2015 | ||
0cbf2b82 | 2016 | #ifndef DISABLE_EVENT |
774ef2d7 | 2017 | if (tb->event_action) |
a7538db1 | 2018 | { |
774ef2d7 | 2019 | state->event_action = tb->event_action; |
a7538db1 | 2020 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2021 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2022 | } |
2023 | #endif | |
2024 | ||
27f19eb4 | 2025 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2026 | state->fd_in = fd; |
2027 | state->fd_out = fd; | |
059ec3d9 | 2028 | |
9d1c15ef | 2029 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2030 | /* There doesn't seem to be a built-in timeout on connection. */ |
2031 | ||
2032 | sigalrm_seen = FALSE; | |
65867078 | 2033 | alarm(ob->command_timeout); |
17c76198 PP |
2034 | do |
2035 | { | |
2036 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
2037 | } while ((rc == GNUTLS_E_AGAIN) || |
2038 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
2039 | alarm(0); |
2040 | ||
4fe99a6c PP |
2041 | if (rc != GNUTLS_E_SUCCESS) |
2042 | return tls_error(US"gnutls_handshake", | |
2043 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
2044 | ||
17c76198 | 2045 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2046 | |
17c76198 | 2047 | /* Verify late */ |
059ec3d9 | 2048 | |
17c76198 PP |
2049 | if (state->verify_requirement != VERIFY_NONE && |
2050 | !verify_certificate(state, &error)) | |
2051 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 2052 | |
f2de3a33 | 2053 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2054 | if (require_ocsp) |
2055 | { | |
2056 | DEBUG(D_tls) | |
2057 | { | |
2058 | gnutls_datum_t stapling; | |
2059 | gnutls_ocsp_resp_t resp; | |
2060 | gnutls_datum_t printed; | |
2061 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2062 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2063 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2064 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2065 | ) | |
2066 | { | |
65867078 | 2067 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2068 | gnutls_free(printed.data); |
2069 | } | |
2070 | else | |
2071 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); | |
2072 | } | |
2073 | ||
2b4a568d | 2074 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2075 | { |
2076 | tls_out.ocsp = OCSP_FAILED; | |
2b4a568d | 2077 | return tls_error(US"certificate status check failed", NULL, state->host); |
018058b2 | 2078 | } |
2b4a568d | 2079 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2080 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2081 | } |
2082 | #endif | |
2083 | ||
17c76198 | 2084 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2085 | |
2b4a568d JH |
2086 | if ((rc = peer_status(state)) != OK) |
2087 | return rc; | |
059ec3d9 | 2088 | |
4fe99a6c | 2089 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2090 | |
9d1c15ef | 2091 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2092 | |
059ec3d9 PH |
2093 | return OK; |
2094 | } | |
2095 | ||
2096 | ||
2097 | ||
17c76198 | 2098 | |
059ec3d9 | 2099 | /************************************************* |
17c76198 | 2100 | * Close down a TLS session * |
059ec3d9 PH |
2101 | *************************************************/ |
2102 | ||
17c76198 PP |
2103 | /* This is also called from within a delivery subprocess forked from the |
2104 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2105 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2106 | |
17c76198 PP |
2107 | Arguments: TRUE if gnutls_bye is to be called |
2108 | Returns: nothing | |
059ec3d9 PH |
2109 | */ |
2110 | ||
17c76198 | 2111 | void |
817d9f57 | 2112 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2113 | { |
817d9f57 | 2114 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2115 | |
389ca47a | 2116 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2117 | |
2118 | if (shutdown) | |
2119 | { | |
2120 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
2121 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
2122 | } | |
2123 | ||
2124 | gnutls_deinit(state->session); | |
2125 | ||
389ca47a | 2126 | state->tlsp->active = -1; |
17c76198 PP |
2127 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2128 | ||
2129 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2130 | { | |
2131 | gnutls_global_deinit(); | |
2132 | exim_gnutls_base_init_done = FALSE; | |
2133 | } | |
7199e1ee | 2134 | |
059ec3d9 PH |
2135 | } |
2136 | ||
2137 | ||
2138 | ||
17c76198 | 2139 | |
059ec3d9 PH |
2140 | /************************************************* |
2141 | * TLS version of getc * | |
2142 | *************************************************/ | |
2143 | ||
2144 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2145 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2146 | Only used by the server-side TLS. |
059ec3d9 | 2147 | |
17c76198 PP |
2148 | This feeds DKIM and should be used for all message-body reads. |
2149 | ||
059ec3d9 PH |
2150 | Arguments: none |
2151 | Returns: the next character or EOF | |
2152 | */ | |
2153 | ||
2154 | int | |
2155 | tls_getc(void) | |
2156 | { | |
817d9f57 | 2157 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 2158 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 2159 | { |
17c76198 | 2160 | ssize_t inbytes; |
059ec3d9 | 2161 | |
17c76198 PP |
2162 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
2163 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
2164 | |
2165 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 2166 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
2167 | ssl_xfer_buffer_size); |
2168 | alarm(0); | |
2169 | ||
2170 | /* A zero-byte return appears to mean that the TLS session has been | |
2171 | closed down, not that the socket itself has been closed down. Revert to | |
2172 | non-TLS handling. */ | |
2173 | ||
2174 | if (inbytes == 0) | |
2175 | { | |
2176 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2177 | ||
2178 | receive_getc = smtp_getc; | |
2179 | receive_ungetc = smtp_ungetc; | |
2180 | receive_feof = smtp_feof; | |
2181 | receive_ferror = smtp_ferror; | |
58eb016e | 2182 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 2183 | |
17c76198 PP |
2184 | gnutls_deinit(state->session); |
2185 | state->session = NULL; | |
817d9f57 JH |
2186 | state->tlsp->active = -1; |
2187 | state->tlsp->bits = 0; | |
2188 | state->tlsp->certificate_verified = FALSE; | |
9d1c15ef | 2189 | tls_channelbinding_b64 = NULL; |
817d9f57 | 2190 | state->tlsp->cipher = NULL; |
9d1c15ef | 2191 | state->tlsp->peercert = NULL; |
817d9f57 | 2192 | state->tlsp->peerdn = NULL; |
059ec3d9 PH |
2193 | |
2194 | return smtp_getc(); | |
2195 | } | |
2196 | ||
2197 | /* Handle genuine errors */ | |
2198 | ||
2199 | else if (inbytes < 0) | |
2200 | { | |
17c76198 PP |
2201 | record_io_error(state, (int) inbytes, US"recv", NULL); |
2202 | state->xfer_error = 1; | |
059ec3d9 PH |
2203 | return EOF; |
2204 | } | |
80a47a2c | 2205 | #ifndef DISABLE_DKIM |
17c76198 | 2206 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 2207 | #endif |
17c76198 PP |
2208 | state->xfer_buffer_hwm = (int) inbytes; |
2209 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
2210 | } |
2211 | ||
059ec3d9 PH |
2212 | /* Something in the buffer; return next uschar */ |
2213 | ||
17c76198 | 2214 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
2215 | } |
2216 | ||
2217 | ||
2218 | ||
17c76198 | 2219 | |
059ec3d9 PH |
2220 | /************************************************* |
2221 | * Read bytes from TLS channel * | |
2222 | *************************************************/ | |
2223 | ||
17c76198 PP |
2224 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2225 | then the caller must feed DKIM. | |
817d9f57 | 2226 | |
059ec3d9 PH |
2227 | Arguments: |
2228 | buff buffer of data | |
2229 | len size of buffer | |
2230 | ||
2231 | Returns: the number of bytes read | |
2232 | -1 after a failed read | |
2233 | */ | |
2234 | ||
2235 | int | |
817d9f57 | 2236 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2237 | { |
817d9f57 | 2238 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2239 | ssize_t inbytes; |
059ec3d9 | 2240 | |
17c76198 PP |
2241 | if (len > INT_MAX) |
2242 | len = INT_MAX; | |
059ec3d9 | 2243 | |
17c76198 PP |
2244 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2245 | DEBUG(D_tls) | |
2246 | debug_printf("*** PROBABLY A BUG *** " \ | |
2247 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2248 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2249 | ||
2250 | DEBUG(D_tls) | |
2251 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2252 | state->session, buff, len); | |
2253 | ||
2254 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2255 | if (inbytes > 0) return inbytes; |
2256 | if (inbytes == 0) | |
2257 | { | |
2258 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2259 | } | |
17c76198 | 2260 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2261 | |
2262 | return -1; | |
2263 | } | |
2264 | ||
2265 | ||
2266 | ||
17c76198 | 2267 | |
059ec3d9 PH |
2268 | /************************************************* |
2269 | * Write bytes down TLS channel * | |
2270 | *************************************************/ | |
2271 | ||
2272 | /* | |
2273 | Arguments: | |
817d9f57 | 2274 | is_server channel specifier |
059ec3d9 PH |
2275 | buff buffer of data |
2276 | len number of bytes | |
2277 | ||
2278 | Returns: the number of bytes after a successful write, | |
2279 | -1 after a failed write | |
2280 | */ | |
2281 | ||
2282 | int | |
817d9f57 | 2283 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 2284 | { |
17c76198 PP |
2285 | ssize_t outbytes; |
2286 | size_t left = len; | |
817d9f57 | 2287 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2288 | |
17c76198 | 2289 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
2290 | while (left > 0) |
2291 | { | |
17c76198 PP |
2292 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2293 | buff, left); | |
2294 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2295 | |
17c76198 | 2296 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2297 | if (outbytes < 0) |
2298 | { | |
17c76198 | 2299 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2300 | return -1; |
2301 | } | |
2302 | if (outbytes == 0) | |
2303 | { | |
17c76198 | 2304 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2305 | return -1; |
2306 | } | |
2307 | ||
2308 | left -= outbytes; | |
2309 | buff += outbytes; | |
2310 | } | |
2311 | ||
17c76198 PP |
2312 | if (len > INT_MAX) |
2313 | { | |
2314 | DEBUG(D_tls) | |
2315 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2316 | len); | |
2317 | len = INT_MAX; | |
2318 | } | |
2319 | ||
2320 | return (int) len; | |
059ec3d9 PH |
2321 | } |
2322 | ||
2323 | ||
2324 | ||
17c76198 | 2325 | |
059ec3d9 | 2326 | /************************************************* |
17c76198 | 2327 | * Random number generation * |
059ec3d9 PH |
2328 | *************************************************/ |
2329 | ||
17c76198 PP |
2330 | /* Pseudo-random number generation. The result is not expected to be |
2331 | cryptographically strong but not so weak that someone will shoot themselves | |
2332 | in the foot using it as a nonce in input in some email header scheme or | |
2333 | whatever weirdness they'll twist this into. The result should handle fork() | |
2334 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2335 | |
17c76198 PP |
2336 | Arguments: |
2337 | max range maximum | |
2338 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2339 | */ |
2340 | ||
af3498d6 | 2341 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2342 | int |
2343 | vaguely_random_number(int max) | |
059ec3d9 | 2344 | { |
17c76198 PP |
2345 | unsigned int r; |
2346 | int i, needed_len; | |
2347 | uschar *p; | |
2348 | uschar smallbuf[sizeof(r)]; | |
2349 | ||
2350 | if (max <= 1) | |
2351 | return 0; | |
2352 | ||
2353 | needed_len = sizeof(r); | |
2354 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2355 | * asked for a number less than 10. */ | |
2356 | for (r = max, i = 0; r; ++i) | |
2357 | r >>= 1; | |
2358 | i = (i + 7) / 8; | |
2359 | if (i < needed_len) | |
2360 | needed_len = i; | |
2361 | ||
2362 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2363 | if (i < 0) | |
059ec3d9 | 2364 | { |
17c76198 PP |
2365 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2366 | return vaguely_random_number_fallback(max); | |
2367 | } | |
2368 | r = 0; | |
2369 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2370 | { | |
2371 | r *= 256; | |
2372 | r += *p; | |
059ec3d9 PH |
2373 | } |
2374 | ||
17c76198 PP |
2375 | /* We don't particularly care about weighted results; if someone wants |
2376 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2377 | return r % max; | |
059ec3d9 | 2378 | } |
af3498d6 PP |
2379 | #else /* HAVE_GNUTLS_RND */ |
2380 | int | |
2381 | vaguely_random_number(int max) | |
2382 | { | |
2383 | return vaguely_random_number_fallback(max); | |
2384 | } | |
2385 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2386 | |
36f12725 NM |
2387 | |
2388 | ||
2389 | ||
3375e053 PP |
2390 | /************************************************* |
2391 | * Let tls_require_ciphers be checked at startup * | |
2392 | *************************************************/ | |
2393 | ||
2394 | /* The tls_require_ciphers option, if set, must be something which the | |
2395 | library can parse. | |
2396 | ||
2397 | Returns: NULL on success, or error message | |
2398 | */ | |
2399 | ||
2400 | uschar * | |
2401 | tls_validate_require_cipher(void) | |
2402 | { | |
2403 | int rc; | |
2404 | uschar *expciphers = NULL; | |
2405 | gnutls_priority_t priority_cache; | |
2406 | const char *errpos; | |
2407 | ||
2408 | #define validate_check_rc(Label) do { \ | |
2409 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2410 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2411 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2412 | ||
2413 | if (exim_gnutls_base_init_done) | |
2414 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2415 | "already initialised GnuTLS, Exim developer bug"); | |
2416 | ||
a5f239e4 | 2417 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2418 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2419 | { |
2420 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2421 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2422 | } | |
2423 | #endif | |
3375e053 PP |
2424 | rc = gnutls_global_init(); |
2425 | validate_check_rc(US"gnutls_global_init()"); | |
2426 | exim_gnutls_base_init_done = TRUE; | |
2427 | ||
2428 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2429 | return_deinit(NULL); | |
2430 | ||
2431 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2432 | return_deinit(US"failed to expand tls_require_ciphers"); | |
2433 | ||
2434 | if (!(expciphers && *expciphers)) | |
2435 | return_deinit(NULL); | |
2436 | ||
2437 | DEBUG(D_tls) | |
2438 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2439 | ||
2440 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2441 | validate_check_rc(string_sprintf( | |
2442 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2443 | expciphers, errpos - CS expciphers, errpos)); | |
2444 | ||
2445 | #undef return_deinit | |
2446 | #undef validate_check_rc | |
2447 | gnutls_global_deinit(); | |
2448 | ||
2449 | return NULL; | |
2450 | } | |
2451 | ||
2452 | ||
2453 | ||
2454 | ||
36f12725 NM |
2455 | /************************************************* |
2456 | * Report the library versions. * | |
2457 | *************************************************/ | |
2458 | ||
2459 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2460 | ||
2461 | Arguments: a FILE* to print the results to | |
2462 | Returns: nothing | |
2463 | */ | |
2464 | ||
2465 | void | |
2466 | tls_version_report(FILE *f) | |
2467 | { | |
754a0503 PP |
2468 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2469 | " Runtime: %s\n", | |
2470 | LIBGNUTLS_VERSION, | |
2471 | gnutls_check_version(NULL)); | |
36f12725 NM |
2472 | } |
2473 | ||
2b4a568d JH |
2474 | /* vi: aw ai sw=2 |
2475 | */ | |
059ec3d9 | 2476 | /* End of tls-gnu.c */ |