Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
17c76198 | 5 | /* Copyright (c) University of Cambridge 1995 - 2012 */ |
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 | |
059ec3d9 | 46 | |
17c76198 | 47 | /* GnuTLS 2 vs 3 |
059ec3d9 | 48 | |
17c76198 PP |
49 | GnuTLS 3 only: |
50 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 51 | |
17c76198 PP |
52 | Changes: |
53 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
54 | */ | |
059ec3d9 | 55 | |
17c76198 | 56 | /* Local static variables for GnuTLS */ |
059ec3d9 | 57 | |
17c76198 | 58 | /* Values for verify_requirement */ |
059ec3d9 | 59 | |
17c76198 | 60 | enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 61 | |
17c76198 PP |
62 | /* This holds most state for server or client; with this, we can set up an |
63 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
64 | over the TLS variables available for expansion. | |
059ec3d9 | 65 | |
17c76198 PP |
66 | Some of these correspond to variables in globals.c; those variables will |
67 | be set to point to content in one of these instances, as appropriate for | |
68 | the stage of the process lifetime. | |
059ec3d9 | 69 | |
389ca47a | 70 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 71 | */ |
059ec3d9 | 72 | |
17c76198 PP |
73 | typedef struct exim_gnutls_state { |
74 | gnutls_session_t session; | |
75 | gnutls_certificate_credentials_t x509_cred; | |
76 | gnutls_priority_t priority_cache; | |
77 | enum peer_verify_requirement verify_requirement; | |
78 | int fd_in; | |
79 | int fd_out; | |
80 | BOOL peer_cert_verified; | |
81 | BOOL trigger_sni_changes; | |
4fe99a6c | 82 | BOOL have_set_peerdn; |
17c76198 PP |
83 | const struct host_item *host; |
84 | uschar *peerdn; | |
75fe387d | 85 | uschar *ciphersuite; |
17c76198 PP |
86 | uschar *received_sni; |
87 | ||
88 | const uschar *tls_certificate; | |
89 | const uschar *tls_privatekey; | |
90 | const uschar *tls_sni; /* client send only, not received */ | |
91 | const uschar *tls_verify_certificates; | |
92 | const uschar *tls_crl; | |
93 | const uschar *tls_require_ciphers; | |
94 | uschar *exp_tls_certificate; | |
95 | uschar *exp_tls_privatekey; | |
96 | uschar *exp_tls_sni; | |
97 | uschar *exp_tls_verify_certificates; | |
98 | uschar *exp_tls_crl; | |
99 | uschar *exp_tls_require_ciphers; | |
100 | ||
389ca47a | 101 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 102 | |
17c76198 PP |
103 | uschar *xfer_buffer; |
104 | int xfer_buffer_lwm; | |
105 | int xfer_buffer_hwm; | |
106 | int xfer_eof; | |
107 | int xfer_error; | |
17c76198 PP |
108 | } exim_gnutls_state_st; |
109 | ||
110 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 111 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 112 | NULL, NULL, NULL, NULL, |
17c76198 PP |
113 | NULL, NULL, NULL, NULL, NULL, NULL, |
114 | NULL, NULL, NULL, NULL, NULL, NULL, | |
817d9f57 | 115 | NULL, |
17c76198 | 116 | NULL, 0, 0, 0, 0, |
17c76198 | 117 | }; |
83da1223 | 118 | |
17c76198 PP |
119 | /* Not only do we have our own APIs which don't pass around state, assuming |
120 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
121 | for callbacks, or as part of the session, so we have to keep a "this is the | |
122 | context we're currently dealing with" pointer and rely upon being | |
123 | single-threaded to keep from processing data on an inbound TLS connection while | |
124 | talking to another TLS connection for an outbound check. This does mean that | |
125 | there's no way for heart-beats to be responded to, for the duration of the | |
126 | second connection. */ | |
059ec3d9 | 127 | |
17c76198 | 128 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 129 | |
17c76198 PP |
130 | /* dh_params are initialised once within the lifetime of a process using TLS; |
131 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
132 | don't want to repeat this. */ | |
83da1223 | 133 | |
17c76198 | 134 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 135 | |
17c76198 | 136 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 137 | |
17c76198 | 138 | static const int ssl_session_timeout = 200; |
059ec3d9 | 139 | |
17c76198 | 140 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 141 | |
17c76198 | 142 | /* Guard library core initialisation */ |
83da1223 | 143 | |
17c76198 | 144 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 145 | |
059ec3d9 | 146 | |
17c76198 PP |
147 | /* ------------------------------------------------------------------------ */ |
148 | /* macros */ | |
83da1223 | 149 | |
17c76198 | 150 | #define MAX_HOST_LEN 255 |
83da1223 | 151 | |
17c76198 PP |
152 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
153 | the library logging; a value less than 0 disables the calls to set up logging | |
154 | callbacks. */ | |
2c17bb02 | 155 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
17c76198 | 156 | #define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 157 | #endif |
83da1223 | 158 | |
2c17bb02 | 159 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
bba74fc6 | 160 | #define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 161 | #endif |
83da1223 | 162 | |
af3498d6 PP |
163 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
164 | can ask for a bit-strength. Without that, we stick to the constant we had | |
165 | before, for now. */ | |
2c17bb02 | 166 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
af3498d6 | 167 | #define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 168 | #endif |
af3498d6 | 169 | |
17c76198 PP |
170 | #define exim_gnutls_err_check(Label) do { \ |
171 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 172 | |
17c76198 | 173 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 174 | |
17c76198 PP |
175 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
176 | #define HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
af3498d6 PP |
177 | #define HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
178 | #define HAVE_GNUTLS_RND | |
a5f239e4 | 179 | #define HAVE_GNUTLS_PKCS11 |
17c76198 | 180 | #endif |
83da1223 | 181 | |
af3498d6 PP |
182 | |
183 | ||
184 | ||
185 | /* ------------------------------------------------------------------------ */ | |
186 | /* Callback declarations */ | |
187 | ||
188 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
189 | static void exim_gnutls_logger_cb(int level, const char *message); | |
190 | #endif | |
191 | ||
192 | static int exim_sni_handling_cb(gnutls_session_t session); | |
193 | ||
194 | ||
195 | ||
196 | ||
17c76198 PP |
197 | /* ------------------------------------------------------------------------ */ |
198 | /* Static functions */ | |
059ec3d9 PH |
199 | |
200 | /************************************************* | |
201 | * Handle TLS error * | |
202 | *************************************************/ | |
203 | ||
204 | /* Called from lots of places when errors occur before actually starting to do | |
205 | the TLS handshake, that is, while the session is still in clear. Always returns | |
206 | DEFER for a server and FAIL for a client so that most calls can use "return | |
207 | tls_error(...)" to do this processing and then give an appropriate return. A | |
208 | single function is used for both server and client, because it is called from | |
209 | some shared functions. | |
210 | ||
211 | Argument: | |
212 | prefix text to include in the logged error | |
7199e1ee TF |
213 | msg additional error string (may be NULL) |
214 | usually obtained from gnutls_strerror() | |
17c76198 PP |
215 | host NULL if setting up a server; |
216 | the connected host if setting up a client | |
059ec3d9 PH |
217 | |
218 | Returns: OK/DEFER/FAIL | |
219 | */ | |
220 | ||
221 | static int | |
17c76198 | 222 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 223 | { |
17c76198 PP |
224 | if (host) |
225 | { | |
226 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", | |
227 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); | |
228 | return FAIL; | |
229 | } | |
230 | else | |
059ec3d9 | 231 | { |
7199e1ee | 232 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 233 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
234 | conn_info += 5; |
235 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", | |
17c76198 | 236 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
237 | return DEFER; |
238 | } | |
059ec3d9 PH |
239 | } |
240 | ||
241 | ||
242 | ||
17c76198 | 243 | |
059ec3d9 | 244 | /************************************************* |
17c76198 | 245 | * Deal with logging errors during I/O * |
059ec3d9 PH |
246 | *************************************************/ |
247 | ||
17c76198 | 248 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 249 | |
17c76198 PP |
250 | Argument: |
251 | state the current GnuTLS exim state container | |
252 | rc the GnuTLS error code, or 0 if it's a local error | |
253 | when text identifying read or write | |
254 | text local error text when ec is 0 | |
059ec3d9 | 255 | |
17c76198 | 256 | Returns: nothing |
059ec3d9 PH |
257 | */ |
258 | ||
17c76198 PP |
259 | static void |
260 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 261 | { |
17c76198 | 262 | const char *msg; |
059ec3d9 | 263 | |
17c76198 PP |
264 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
265 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
266 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
267 | else | |
268 | msg = gnutls_strerror(rc); | |
059ec3d9 | 269 | |
17c76198 PP |
270 | tls_error(when, msg, state->host); |
271 | } | |
059ec3d9 | 272 | |
059ec3d9 | 273 | |
059ec3d9 | 274 | |
059ec3d9 | 275 | |
17c76198 PP |
276 | /************************************************* |
277 | * Set various Exim expansion vars * | |
278 | *************************************************/ | |
059ec3d9 | 279 | |
17c76198 PP |
280 | /* We set various Exim global variables from the state, once a session has |
281 | been established. With TLS callouts, may need to change this to stack | |
282 | variables, or just re-call it with the server state after client callout | |
283 | has finished. | |
059ec3d9 | 284 | |
17c76198 PP |
285 | Make sure anything set here is inset in tls_getc(). |
286 | ||
287 | Sets: | |
288 | tls_active fd | |
289 | tls_bits strength indicator | |
290 | tls_certificate_verified bool indicator | |
291 | tls_channelbinding_b64 for some SASL mechanisms | |
292 | tls_cipher a string | |
293 | tls_peerdn a string | |
294 | tls_sni a (UTF-8) string | |
17c76198 PP |
295 | |
296 | Argument: | |
297 | state the relevant exim_gnutls_state_st * | |
298 | */ | |
299 | ||
300 | static void | |
817d9f57 | 301 | extract_exim_vars_from_tls_state(exim_gnutls_state_st *state, BOOL is_server) |
17c76198 | 302 | { |
17c76198 | 303 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
304 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
305 | int old_pool; | |
306 | int rc; | |
307 | gnutls_datum_t channel; | |
308 | #endif | |
309 | ||
817d9f57 | 310 | state->tlsp->active = state->fd_out; |
17c76198 PP |
311 | |
312 | cipher = gnutls_cipher_get(state->session); | |
313 | /* returns size in "bytes" */ | |
817d9f57 | 314 | state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 315 | |
817d9f57 | 316 | state->tlsp->cipher = state->ciphersuite; |
17c76198 | 317 | |
817d9f57 | 318 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 319 | |
817d9f57 | 320 | state->tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 321 | |
17c76198 PP |
322 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
323 | only available for use for authenticators while this TLS session is running. */ | |
324 | ||
325 | tls_channelbinding_b64 = NULL; | |
326 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
327 | channel.data = NULL; | |
328 | channel.size = 0; | |
329 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
330 | if (rc) { | |
331 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
332 | } else { | |
333 | old_pool = store_pool; | |
334 | store_pool = POOL_PERM; | |
335 | tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); | |
336 | store_pool = old_pool; | |
337 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
338 | } | |
339 | #endif | |
340 | ||
817d9f57 JH |
341 | state->tlsp->peerdn = state->peerdn; |
342 | state->tlsp->sni = state->received_sni; | |
059ec3d9 PH |
343 | } |
344 | ||
345 | ||
346 | ||
17c76198 | 347 | |
059ec3d9 | 348 | /************************************************* |
575643cd | 349 | * Setup up DH parameters * |
059ec3d9 PH |
350 | *************************************************/ |
351 | ||
575643cd | 352 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
353 | be re-generated every so often, depending on security policy. What we do is to |
354 | keep these parameters in a file in the spool directory. If the file does not | |
355 | exist, we generate them. This means that it is easy to cause a regeneration. | |
356 | ||
357 | The new file is written as a temporary file and renamed, so that an incomplete | |
358 | file is never present. If two processes both compute some new parameters, you | |
359 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
360 | prevent this. | |
361 | ||
059ec3d9 PH |
362 | Returns: OK/DEFER/FAIL |
363 | */ | |
364 | ||
365 | static int | |
17c76198 | 366 | init_server_dh(void) |
059ec3d9 | 367 | { |
17c76198 PP |
368 | int fd, rc; |
369 | unsigned int dh_bits; | |
b5aea5e1 | 370 | gnutls_datum m; |
a799883d PP |
371 | uschar filename_buf[PATH_MAX]; |
372 | uschar *filename = NULL; | |
17c76198 | 373 | size_t sz; |
a799883d PP |
374 | uschar *exp_tls_dhparam; |
375 | BOOL use_file_in_spool = FALSE; | |
376 | BOOL use_fixed_file = FALSE; | |
17c76198 | 377 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 378 | |
17c76198 | 379 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 380 | |
17c76198 PP |
381 | rc = gnutls_dh_params_init(&dh_server_params); |
382 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 383 | |
a799883d PP |
384 | m.data = NULL; |
385 | m.size = 0; | |
386 | ||
387 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
388 | return DEFER; | |
389 | ||
390 | if (!exp_tls_dhparam) | |
391 | { | |
392 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
393 | m.data = US std_dh_prime_default(); | |
394 | m.size = Ustrlen(m.data); | |
395 | } | |
396 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
397 | use_file_in_spool = TRUE; | |
398 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
399 | { | |
400 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
401 | return OK; | |
402 | } | |
403 | else if (exp_tls_dhparam[0] != '/') | |
404 | { | |
405 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
406 | if (m.data == NULL) | |
407 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
408 | m.size = Ustrlen(m.data); | |
409 | } | |
410 | else | |
411 | { | |
412 | use_fixed_file = TRUE; | |
413 | filename = exp_tls_dhparam; | |
414 | } | |
415 | ||
416 | if (m.data) | |
417 | { | |
418 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
419 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
420 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
421 | return OK; | |
422 | } | |
423 | ||
af3498d6 PP |
424 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
425 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
426 | different filename and ensure we have sufficient bits. */ |
427 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
428 | if (!dh_bits) | |
429 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 430 | DEBUG(D_tls) |
b34fc30c | 431 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
432 | dh_bits); |
433 | #else | |
434 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
435 | DEBUG(D_tls) | |
436 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
437 | dh_bits); | |
438 | #endif | |
059ec3d9 | 439 | |
3375e053 PP |
440 | /* Some clients have hard-coded limits. */ |
441 | if (dh_bits > tls_dh_max_bits) | |
442 | { | |
443 | DEBUG(D_tls) | |
444 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
445 | tls_dh_max_bits); | |
446 | dh_bits = tls_dh_max_bits; | |
447 | } | |
448 | ||
a799883d PP |
449 | if (use_file_in_spool) |
450 | { | |
451 | if (!string_format(filename_buf, sizeof(filename_buf), | |
452 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
453 | return tls_error(US"overlong filename", NULL, NULL); | |
454 | filename = filename_buf; | |
455 | } | |
059ec3d9 | 456 | |
b5aea5e1 | 457 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 458 | parameters. */ |
059ec3d9 PH |
459 | |
460 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 461 | if (fd >= 0) |
059ec3d9 | 462 | { |
b5aea5e1 | 463 | struct stat statbuf; |
17c76198 PP |
464 | FILE *fp; |
465 | int saved_errno; | |
466 | ||
467 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
468 | { | |
469 | saved_errno = errno; | |
470 | (void)close(fd); | |
471 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
472 | } | |
473 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
474 | { |
475 | (void)close(fd); | |
17c76198 PP |
476 | return tls_error(US"TLS cache not a file", NULL, NULL); |
477 | } | |
478 | fp = fdopen(fd, "rb"); | |
479 | if (!fp) | |
480 | { | |
481 | saved_errno = errno; | |
482 | (void)close(fd); | |
483 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
484 | strerror(saved_errno), NULL); | |
b5aea5e1 | 485 | } |
059ec3d9 | 486 | |
b5aea5e1 PH |
487 | m.size = statbuf.st_size; |
488 | m.data = malloc(m.size); | |
489 | if (m.data == NULL) | |
17c76198 PP |
490 | { |
491 | fclose(fp); | |
492 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
493 | } | |
494 | sz = fread(m.data, m.size, 1, fp); | |
495 | if (!sz) | |
496 | { | |
497 | saved_errno = errno; | |
498 | fclose(fp); | |
499 | free(m.data); | |
500 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
501 | } | |
502 | fclose(fp); | |
b5aea5e1 | 503 | |
17c76198 | 504 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 505 | free(m.data); |
17c76198 PP |
506 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
507 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
508 | } |
509 | ||
510 | /* If the file does not exist, fall through to compute new data and cache it. | |
511 | If there was any other opening error, it is serious. */ | |
512 | ||
182ad5cf PH |
513 | else if (errno == ENOENT) |
514 | { | |
17c76198 | 515 | rc = -1; |
182ad5cf | 516 | DEBUG(D_tls) |
17c76198 | 517 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
518 | } |
519 | else | |
17c76198 PP |
520 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
521 | NULL, NULL); | |
b5aea5e1 PH |
522 | |
523 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
524 | is not useful. One particular case of this is when upgrading from an older | |
525 | release of Exim in which the data was stored in a different format. We don't | |
526 | try to be clever and support both formats; we just regenerate new data in this | |
527 | case. */ | |
528 | ||
17c76198 | 529 | if (rc < 0) |
b5aea5e1 | 530 | { |
17c76198 | 531 | uschar *temp_fn; |
201f5254 | 532 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 533 | |
17c76198 PP |
534 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
535 | return tls_error(US"Filename too long to generate replacement", | |
536 | CS filename, NULL); | |
059ec3d9 | 537 | |
17c76198 PP |
538 | temp_fn = string_copy(US "%s.XXXXXXX"); |
539 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 540 | if (fd < 0) |
17c76198 | 541 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
542 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
543 | ||
201f5254 PP |
544 | /* GnuTLS overshoots! |
545 | * If we ask for 2236, we might get 2237 or more. | |
546 | * But there's no way to ask GnuTLS how many bits there really are. | |
547 | * We can ask how many bits were used in a TLS session, but that's it! | |
548 | * The prime itself is hidden behind too much abstraction. | |
549 | * So we ask for less, and proceed on a wing and a prayer. | |
550 | * First attempt, subtracted 3 for 2233 and got 2240. | |
551 | */ | |
cae6e576 | 552 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
553 | { |
554 | dh_bits_gen = dh_bits - 10; | |
555 | DEBUG(D_tls) | |
556 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
557 | dh_bits_gen); | |
558 | } | |
559 | ||
560 | DEBUG(D_tls) | |
561 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
562 | dh_bits_gen); | |
563 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
564 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
565 | ||
566 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
567 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
568 | sample apps handle this. */ | |
569 | ||
570 | sz = 0; | |
571 | m.data = NULL; | |
572 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
573 | m.data, &sz); | |
574 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
575 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
576 | m.size = sz; | |
b5aea5e1 PH |
577 | m.data = malloc(m.size); |
578 | if (m.data == NULL) | |
17c76198 | 579 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
1f00591e | 580 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 581 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 582 | m.data, &sz); |
17c76198 PP |
583 | if (rc != GNUTLS_E_SUCCESS) |
584 | { | |
585 | free(m.data); | |
586 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
587 | } | |
1f00591e | 588 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 589 | |
17c76198 PP |
590 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
591 | if (sz != m.size) | |
592 | { | |
593 | free(m.data); | |
594 | return tls_error(US"TLS cache write D-H params failed", | |
595 | strerror(errno), NULL); | |
596 | } | |
b5aea5e1 | 597 | free(m.data); |
17c76198 PP |
598 | sz = write_to_fd_buf(fd, US"\n", 1); |
599 | if (sz != 1) | |
600 | return tls_error(US"TLS cache write D-H params final newline failed", | |
601 | strerror(errno), NULL); | |
602 | ||
603 | rc = close(fd); | |
604 | if (rc) | |
605 | return tls_error(US"TLS cache write close() failed", | |
606 | strerror(errno), NULL); | |
059ec3d9 | 607 | |
17c76198 PP |
608 | if (Urename(temp_fn, filename) < 0) |
609 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
610 | temp_fn, filename), strerror(errno), NULL); | |
059ec3d9 | 611 | |
17c76198 | 612 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
613 | } |
614 | ||
17c76198 | 615 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
616 | return OK; |
617 | } | |
618 | ||
619 | ||
620 | ||
621 | ||
622 | /************************************************* | |
17c76198 | 623 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
624 | *************************************************/ |
625 | ||
17c76198 PP |
626 | /* Called from both server and client code, via tls_init(), and also from |
627 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
628 | ||
629 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
630 | ||
631 | The callback should not call us unless state->trigger_sni_changes is true, | |
632 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
633 | |
634 | Arguments: | |
17c76198 | 635 | state exim_gnutls_state_st * |
059ec3d9 PH |
636 | |
637 | Returns: OK/DEFER/FAIL | |
638 | */ | |
639 | ||
640 | static int | |
17c76198 | 641 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 642 | { |
1365611d | 643 | struct stat statbuf; |
059ec3d9 | 644 | int rc; |
17c76198 PP |
645 | const host_item *host = state->host; /* macro should be reconsidered? */ |
646 | uschar *saved_tls_certificate = NULL; | |
647 | uschar *saved_tls_privatekey = NULL; | |
648 | uschar *saved_tls_verify_certificates = NULL; | |
649 | uschar *saved_tls_crl = NULL; | |
650 | int cert_count; | |
651 | ||
652 | /* We check for tls_sni *before* expansion. */ | |
653 | if (!state->host) | |
654 | { | |
655 | if (!state->received_sni) | |
656 | { | |
d9b2312b JH |
657 | if (state->tls_certificate && |
658 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
659 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
660 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
661 | )) | |
17c76198 PP |
662 | { |
663 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
664 | state->trigger_sni_changes = TRUE; | |
665 | } | |
666 | } | |
667 | else | |
668 | { | |
1365611d | 669 | /* useful for debugging */ |
17c76198 PP |
670 | saved_tls_certificate = state->exp_tls_certificate; |
671 | saved_tls_privatekey = state->exp_tls_privatekey; | |
672 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
673 | saved_tls_crl = state->exp_tls_crl; | |
674 | } | |
675 | } | |
059ec3d9 | 676 | |
1365611d PP |
677 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
678 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
679 | ||
17c76198 PP |
680 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
681 | state members, assuming consistent naming; and expand_check() returns | |
682 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 683 | |
17c76198 PP |
684 | /* check if we at least have a certificate, before doing expensive |
685 | D-H generation. */ | |
059ec3d9 | 686 | |
17c76198 PP |
687 | if (!expand_check_tlsvar(tls_certificate)) |
688 | return DEFER; | |
059ec3d9 | 689 | |
17c76198 | 690 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 691 | |
17c76198 PP |
692 | if ((state->exp_tls_certificate == NULL) || |
693 | (*state->exp_tls_certificate == '\0')) | |
694 | { | |
695 | if (state->host == NULL) | |
696 | return tls_error(US"no TLS server certificate is specified", NULL, NULL); | |
697 | else | |
698 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
699 | } | |
059ec3d9 | 700 | |
17c76198 | 701 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
702 | return DEFER; |
703 | ||
17c76198 PP |
704 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
705 | ||
706 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 707 | { |
17c76198 PP |
708 | state->tls_privatekey = state->tls_certificate; |
709 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 710 | } |
c91535f3 | 711 | |
059ec3d9 | 712 | |
17c76198 | 713 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
714 | { |
715 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
716 | state->exp_tls_certificate, state->exp_tls_privatekey); |
717 | ||
718 | if (state->received_sni) | |
de365ded | 719 | { |
17c76198 PP |
720 | if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && |
721 | (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) | |
722 | { | |
b34fc30c | 723 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
724 | } |
725 | else | |
726 | { | |
b34fc30c | 727 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 728 | } |
8e669ac1 | 729 | } |
059ec3d9 | 730 | |
1365611d PP |
731 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
732 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
733 | GNUTLS_X509_FMT_PEM); | |
734 | exim_gnutls_err_check( | |
735 | string_sprintf("cert/key setup: cert=%s key=%s", | |
736 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
737 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 738 | } /* tls_certificate */ |
059ec3d9 PH |
739 | |
740 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is | |
741 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
742 | error message is provided. However, if we just refrain from setting anything up | |
743 | in that case, certificate verification fails, which seems to be the correct | |
744 | behaviour. */ | |
745 | ||
17c76198 | 746 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 747 | { |
17c76198 | 748 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 749 | return DEFER; |
17c76198 PP |
750 | if (state->tls_crl && *state->tls_crl) |
751 | if (!expand_check_tlsvar(tls_crl)) | |
752 | return DEFER; | |
059ec3d9 | 753 | |
1365611d PP |
754 | if (!(state->exp_tls_verify_certificates && |
755 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
756 | { |
757 | DEBUG(D_tls) | |
1365611d PP |
758 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
759 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 760 | return OK; |
b34fc30c | 761 | } |
1365611d | 762 | } |
83e2f8a2 PP |
763 | else |
764 | { | |
765 | DEBUG(D_tls) | |
766 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
767 | return OK; | |
768 | } | |
17c76198 | 769 | |
1365611d PP |
770 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
771 | { | |
772 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
773 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
774 | strerror(errno)); | |
775 | return DEFER; | |
776 | } | |
17c76198 | 777 | |
619b2b25 PP |
778 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
779 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
780 | other weirdness. The thing we really want to check is that it's not a | |
781 | directory, since while OpenSSL supports that, GnuTLS does not. | |
782 | So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ | |
783 | if (S_ISDIR(statbuf.st_mode)) | |
1365611d PP |
784 | { |
785 | DEBUG(D_tls) | |
619b2b25 PP |
786 | debug_printf("verify certificates path is a dir: \"%s\"\n", |
787 | state->exp_tls_verify_certificates); | |
1365611d | 788 | log_write(0, LOG_MAIN|LOG_PANIC, |
619b2b25 | 789 | "tls_verify_certificates \"%s\" is a directory", |
1365611d PP |
790 | state->exp_tls_verify_certificates); |
791 | return DEFER; | |
792 | } | |
059ec3d9 | 793 | |
1365611d PP |
794 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
795 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 796 | |
1365611d PP |
797 | if (statbuf.st_size == 0) |
798 | { | |
799 | DEBUG(D_tls) | |
800 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
801 | return OK; | |
802 | } | |
059ec3d9 | 803 | |
1365611d PP |
804 | cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, |
805 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
806 | if (cert_count < 0) | |
807 | { | |
808 | rc = cert_count; | |
809 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); | |
810 | } | |
811 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 812 | |
5c8cda3a PP |
813 | if (state->tls_crl && *state->tls_crl && |
814 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 815 | { |
5c8cda3a PP |
816 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
817 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
818 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
819 | if (cert_count < 0) | |
1365611d | 820 | { |
5c8cda3a | 821 | rc = cert_count; |
1365611d PP |
822 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
823 | } | |
5c8cda3a | 824 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 825 | } |
059ec3d9 | 826 | |
059ec3d9 PH |
827 | return OK; |
828 | } | |
829 | ||
830 | ||
831 | ||
832 | ||
1365611d PP |
833 | /************************************************* |
834 | * Set X.509 state variables * | |
835 | *************************************************/ | |
836 | ||
837 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
838 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
839 | structure. Which means various other non-re-expanded pieces of state | |
840 | need to be re-set in the new struct, so the setting logic is pulled | |
841 | out to this. | |
842 | ||
843 | Arguments: | |
844 | state exim_gnutls_state_st * | |
845 | ||
846 | Returns: OK/DEFER/FAIL | |
847 | */ | |
848 | ||
849 | static int | |
850 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
851 | { | |
852 | int rc; | |
853 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
854 | ||
855 | /* Create D-H parameters, or read them from the cache file. This function does | |
856 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
857 | client-side params. */ | |
858 | ||
859 | if (!state->host) | |
860 | { | |
861 | if (!dh_server_params) | |
862 | { | |
863 | rc = init_server_dh(); | |
864 | if (rc != OK) return rc; | |
865 | } | |
866 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
867 | } | |
868 | ||
869 | /* Link the credentials to the session. */ | |
870 | ||
871 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
872 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
873 | ||
874 | return OK; | |
875 | } | |
876 | ||
059ec3d9 | 877 | /************************************************* |
17c76198 | 878 | * Initialize for GnuTLS * |
059ec3d9 PH |
879 | *************************************************/ |
880 | ||
17c76198 PP |
881 | /* Called from both server and client code. In the case of a server, errors |
882 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
883 | |
884 | Arguments: | |
17c76198 PP |
885 | host connected host, if client; NULL if server |
886 | certificate certificate file | |
887 | privatekey private key file | |
888 | sni TLS SNI to send, sometimes when client; else NULL | |
889 | cas CA certs file | |
890 | crl CRL file | |
891 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 892 | caller_state returned state-info structure |
059ec3d9 | 893 | |
17c76198 | 894 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
895 | */ |
896 | ||
17c76198 PP |
897 | static int |
898 | tls_init( | |
899 | const host_item *host, | |
900 | const uschar *certificate, | |
901 | const uschar *privatekey, | |
902 | const uschar *sni, | |
903 | const uschar *cas, | |
904 | const uschar *crl, | |
905 | const uschar *require_ciphers, | |
906 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 907 | { |
17c76198 PP |
908 | exim_gnutls_state_st *state; |
909 | int rc; | |
910 | size_t sz; | |
911 | const char *errpos; | |
912 | uschar *p; | |
913 | BOOL want_default_priorities; | |
914 | ||
915 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 916 | { |
17c76198 PP |
917 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
918 | ||
a5f239e4 PP |
919 | #ifdef HAVE_GNUTLS_PKCS11 |
920 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
921 | which loads modules from a config file, which sounds good and may be wanted | |
922 | by some sysadmin, but also means in common configurations that GNOME keyring | |
923 | environment variables are used and so breaks for users calling mailq. | |
924 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
925 | if (!gnutls_enable_pkcs11) | |
926 | { | |
927 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
928 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
929 | } | |
930 | #endif | |
931 | ||
17c76198 PP |
932 | rc = gnutls_global_init(); |
933 | exim_gnutls_err_check(US"gnutls_global_init"); | |
934 | ||
935 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
936 | DEBUG(D_tls) | |
059ec3d9 | 937 | { |
17c76198 PP |
938 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
939 | /* arbitrarily chosen level; bump upto 9 for more */ | |
940 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 941 | } |
17c76198 PP |
942 | #endif |
943 | ||
944 | exim_gnutls_base_init_done = TRUE; | |
059ec3d9 | 945 | } |
059ec3d9 | 946 | |
17c76198 PP |
947 | if (host) |
948 | { | |
949 | state = &state_client; | |
950 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 951 | state->tlsp = &tls_out; |
17c76198 PP |
952 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
953 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
954 | } | |
955 | else | |
956 | { | |
957 | state = &state_server; | |
958 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 959 | state->tlsp = &tls_in; |
17c76198 PP |
960 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
961 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
962 | } | |
963 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 964 | |
17c76198 | 965 | state->host = host; |
059ec3d9 | 966 | |
17c76198 PP |
967 | state->tls_certificate = certificate; |
968 | state->tls_privatekey = privatekey; | |
5779e6aa | 969 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
970 | state->tls_sni = sni; |
971 | state->tls_verify_certificates = cas; | |
972 | state->tls_crl = crl; | |
059ec3d9 | 973 | |
17c76198 PP |
974 | /* This handles the variables that might get re-expanded after TLS SNI; |
975 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 976 | |
17c76198 PP |
977 | DEBUG(D_tls) |
978 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
979 | rc = tls_expand_session_files(state); | |
980 | if (rc != OK) return rc; | |
059ec3d9 | 981 | |
1365611d PP |
982 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
983 | requires a new structure afterwards. */ | |
83da1223 | 984 | |
1365611d PP |
985 | rc = tls_set_remaining_x509(state); |
986 | if (rc != OK) return rc; | |
83da1223 | 987 | |
17c76198 PP |
988 | /* set SNI in client, only */ |
989 | if (host) | |
990 | { | |
a5f239e4 | 991 | if (!expand_check(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni)) |
17c76198 PP |
992 | return DEFER; |
993 | if (state->exp_tls_sni && *state->exp_tls_sni) | |
994 | { | |
995 | DEBUG(D_tls) | |
996 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); | |
997 | sz = Ustrlen(state->exp_tls_sni); | |
998 | rc = gnutls_server_name_set(state->session, | |
999 | GNUTLS_NAME_DNS, state->exp_tls_sni, sz); | |
1000 | exim_gnutls_err_check(US"gnutls_server_name_set"); | |
1001 | } | |
1002 | } | |
1003 | else if (state->tls_sni) | |
1004 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1005 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1006 | |
17c76198 PP |
1007 | /* This is the priority string support, |
1008 | http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html | |
1009 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. | |
1010 | This was backwards incompatible, but means Exim no longer needs to track | |
1011 | all algorithms and provide string forms for them. */ | |
83da1223 | 1012 | |
17c76198 | 1013 | want_default_priorities = TRUE; |
83da1223 | 1014 | |
17c76198 | 1015 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1016 | { |
17c76198 PP |
1017 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1018 | return DEFER; | |
1019 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1020 | { |
17c76198 PP |
1021 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1022 | state->exp_tls_require_ciphers); | |
1023 | ||
1024 | rc = gnutls_priority_init(&state->priority_cache, | |
1025 | CS state->exp_tls_require_ciphers, &errpos); | |
1026 | want_default_priorities = FALSE; | |
1027 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1028 | } |
1029 | } | |
17c76198 PP |
1030 | if (want_default_priorities) |
1031 | { | |
83e2f8a2 PP |
1032 | DEBUG(D_tls) |
1033 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1034 | exim_default_gnutls_priority); | |
17c76198 PP |
1035 | rc = gnutls_priority_init(&state->priority_cache, |
1036 | exim_default_gnutls_priority, &errpos); | |
1037 | p = US exim_default_gnutls_priority; | |
1038 | } | |
83da1223 | 1039 | |
17c76198 PP |
1040 | exim_gnutls_err_check(string_sprintf( |
1041 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1042 | p, errpos - CS p, errpos)); | |
1043 | ||
1044 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1045 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1046 | ||
1047 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1048 | ||
1049 | /* Reduce security in favour of increased compatibility, if the admin | |
1050 | decides to make that trade-off. */ | |
1051 | if (gnutls_compat_mode) | |
83da1223 | 1052 | { |
17c76198 PP |
1053 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1054 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1055 | gnutls_session_enable_compatibility_mode(state->session); | |
1056 | #else | |
1057 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1058 | #endif | |
83da1223 PH |
1059 | } |
1060 | ||
17c76198 | 1061 | *caller_state = state; |
17c76198 | 1062 | return OK; |
83da1223 PH |
1063 | } |
1064 | ||
1065 | ||
1066 | ||
1067 | ||
059ec3d9 | 1068 | /************************************************* |
17c76198 | 1069 | * Extract peer information * |
059ec3d9 PH |
1070 | *************************************************/ |
1071 | ||
17c76198 | 1072 | /* Called from both server and client code. |
4fe99a6c PP |
1073 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1074 | and we use that to detect double-calls. | |
059ec3d9 | 1075 | |
75fe387d PP |
1076 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1077 | for logging in the server side, but for the client side, we log after teardown | |
1078 | in src/deliver.c. While the session is up, we can twist about states and | |
1079 | repoint tls_* globals, but those variables used for logging or other variable | |
1080 | expansion that happens _after_ delivery need to have a longer life-time. | |
1081 | ||
1082 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1083 | doing this more than once per generation of a state context. We set them in | |
1084 | the state context, and repoint tls_* to them. After the state goes away, the | |
1085 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1086 | ||
1087 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1088 | don't apply. | |
1089 | ||
059ec3d9 | 1090 | Arguments: |
17c76198 | 1091 | state exim_gnutls_state_st * |
059ec3d9 | 1092 | |
17c76198 | 1093 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1094 | */ |
1095 | ||
17c76198 PP |
1096 | static int |
1097 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1098 | { |
75fe387d | 1099 | uschar cipherbuf[256]; |
17c76198 | 1100 | const gnutls_datum *cert_list; |
75fe387d | 1101 | int old_pool, rc; |
17c76198 | 1102 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1103 | gnutls_protocol_t protocol; |
1104 | gnutls_cipher_algorithm_t cipher; | |
1105 | gnutls_kx_algorithm_t kx; | |
1106 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1107 | gnutls_certificate_type_t ct; |
1108 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1109 | uschar *p, *dn_buf; |
17c76198 | 1110 | size_t sz; |
059ec3d9 | 1111 | |
4fe99a6c | 1112 | if (state->have_set_peerdn) |
17c76198 | 1113 | return OK; |
4fe99a6c | 1114 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1115 | |
4fe99a6c | 1116 | state->peerdn = NULL; |
059ec3d9 | 1117 | |
4fe99a6c PP |
1118 | /* tls_cipher */ |
1119 | cipher = gnutls_cipher_get(state->session); | |
1120 | protocol = gnutls_protocol_get_version(state->session); | |
1121 | mac = gnutls_mac_get(state->session); | |
1122 | kx = gnutls_kx_get(state->session); | |
1123 | ||
75fe387d | 1124 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1125 | "%s:%s:%d", |
1126 | gnutls_protocol_get_name(protocol), | |
1127 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1128 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1129 | ||
1130 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1131 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1132 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1133 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1134 | if (isspace(*p)) |
1135 | *p = '-'; | |
75fe387d PP |
1136 | old_pool = store_pool; |
1137 | store_pool = POOL_PERM; | |
1138 | state->ciphersuite = string_copy(cipherbuf); | |
1139 | store_pool = old_pool; | |
817d9f57 | 1140 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1141 | |
1142 | /* tls_peerdn */ | |
17c76198 | 1143 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1144 | |
17c76198 PP |
1145 | if (cert_list == NULL || cert_list_size == 0) |
1146 | { | |
17c76198 PP |
1147 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1148 | cert_list, cert_list_size); | |
1149 | if (state->verify_requirement == VERIFY_REQUIRED) | |
1150 | return tls_error(US"certificate verification failed", | |
1151 | "no certificate received from peer", state->host); | |
1152 | return OK; | |
1153 | } | |
059ec3d9 | 1154 | |
17c76198 PP |
1155 | ct = gnutls_certificate_type_get(state->session); |
1156 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1157 | { |
17c76198 | 1158 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1159 | DEBUG(D_tls) |
1160 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
1161 | if (state->verify_requirement == VERIFY_REQUIRED) | |
1162 | return tls_error(US"certificate verification not possible, unhandled type", | |
1163 | ctn, state->host); | |
1164 | return OK; | |
83da1223 | 1165 | } |
059ec3d9 | 1166 | |
17c76198 PP |
1167 | #define exim_gnutls_peer_err(Label) do { \ |
1168 | if (rc != GNUTLS_E_SUCCESS) { \ | |
1169 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \ | |
1170 | if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \ | |
1171 | return OK; } } while (0) | |
1172 | ||
1173 | rc = gnutls_x509_crt_init(&crt); | |
1174 | exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)"); | |
1175 | ||
1176 | rc = gnutls_x509_crt_import(crt, &cert_list[0], GNUTLS_X509_FMT_DER); | |
1177 | exim_gnutls_peer_err(US"failed to import certificate [gnutls_x509_crt_import(cert 0)]"); | |
1178 | sz = 0; | |
1179 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1180 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1181 | { |
17c76198 PP |
1182 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1183 | return FAIL; /* should not happen */ | |
059ec3d9 | 1184 | } |
17c76198 PP |
1185 | dn_buf = store_get_perm(sz); |
1186 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1187 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
1188 | state->peerdn = dn_buf; | |
1189 | ||
1190 | return OK; | |
1191 | #undef exim_gnutls_peer_err | |
1192 | } | |
059ec3d9 | 1193 | |
059ec3d9 | 1194 | |
059ec3d9 | 1195 | |
059ec3d9 | 1196 | |
17c76198 PP |
1197 | /************************************************* |
1198 | * Verify peer certificate * | |
1199 | *************************************************/ | |
059ec3d9 | 1200 | |
17c76198 PP |
1201 | /* Called from both server and client code. |
1202 | *Should* be using a callback registered with | |
1203 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1204 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1205 | |
17c76198 PP |
1206 | Arguments: |
1207 | state exim_gnutls_state_st * | |
1208 | error where to put an error message | |
059ec3d9 | 1209 | |
17c76198 PP |
1210 | Returns: |
1211 | FALSE if the session should be rejected | |
1212 | TRUE if the cert is okay or we just don't care | |
1213 | */ | |
059ec3d9 | 1214 | |
17c76198 PP |
1215 | static BOOL |
1216 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1217 | { | |
1218 | int rc; | |
1219 | unsigned int verify; | |
1220 | ||
1221 | *error = NULL; | |
1222 | ||
1223 | rc = peer_status(state); | |
1224 | if (rc != OK) | |
e6060e2c | 1225 | { |
17c76198 PP |
1226 | verify = GNUTLS_CERT_INVALID; |
1227 | *error = "not supplied"; | |
1228 | } | |
1229 | else | |
1230 | { | |
1231 | rc = gnutls_certificate_verify_peers2(state->session, &verify); | |
e6060e2c NM |
1232 | } |
1233 | ||
17c76198 PP |
1234 | /* Handle the result of verification. INVALID seems to be set as well |
1235 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1236 | |
17c76198 PP |
1237 | if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) |
1238 | { | |
1239 | state->peer_cert_verified = FALSE; | |
1240 | if (*error == NULL) | |
1241 | *error = ((verify & GNUTLS_CERT_REVOKED) != 0) ? "revoked" : "invalid"; | |
059ec3d9 | 1242 | |
17c76198 PP |
1243 | DEBUG(D_tls) |
1244 | debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", | |
4fe99a6c | 1245 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1246 | |
17c76198 PP |
1247 | if (state->verify_requirement == VERIFY_REQUIRED) |
1248 | { | |
1249 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1250 | return FALSE; | |
1251 | } | |
1252 | DEBUG(D_tls) | |
4789da3a | 1253 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 PP |
1254 | } |
1255 | else | |
1256 | { | |
1257 | state->peer_cert_verified = TRUE; | |
4fe99a6c PP |
1258 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", |
1259 | state->peerdn ? state->peerdn : US"<unset>"); | |
17c76198 | 1260 | } |
059ec3d9 | 1261 | |
817d9f57 | 1262 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1263 | |
17c76198 PP |
1264 | return TRUE; |
1265 | } | |
059ec3d9 | 1266 | |
17c76198 PP |
1267 | |
1268 | ||
1269 | ||
1270 | /* ------------------------------------------------------------------------ */ | |
1271 | /* Callbacks */ | |
1272 | ||
1273 | /* Logging function which can be registered with | |
1274 | * gnutls_global_set_log_function() | |
1275 | * gnutls_global_set_log_level() 0..9 | |
1276 | */ | |
af3498d6 | 1277 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1278 | static void |
17c76198 | 1279 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1280 | { |
8c79eebf PP |
1281 | size_t len = strlen(message); |
1282 | if (len < 1) | |
1283 | { | |
1284 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1285 | return; | |
1286 | } | |
1287 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1288 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1289 | } |
af3498d6 | 1290 | #endif |
059ec3d9 | 1291 | |
059ec3d9 | 1292 | |
17c76198 PP |
1293 | /* Called after client hello, should handle SNI work. |
1294 | This will always set tls_sni (state->received_sni) if available, | |
1295 | and may trigger presenting different certificates, | |
1296 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1297 | |
17c76198 PP |
1298 | Should be registered with |
1299 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1300 | |
17c76198 PP |
1301 | "This callback must return 0 on success or a gnutls error code to terminate the |
1302 | handshake.". | |
059ec3d9 | 1303 | |
17c76198 PP |
1304 | For inability to get SNI information, we return 0. |
1305 | We only return non-zero if re-setup failed. | |
817d9f57 | 1306 | Only used for server-side TLS. |
17c76198 | 1307 | */ |
44bbabb5 | 1308 | |
17c76198 PP |
1309 | static int |
1310 | exim_sni_handling_cb(gnutls_session_t session) | |
1311 | { | |
1312 | char sni_name[MAX_HOST_LEN]; | |
1313 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1314 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1315 | unsigned int sni_type; |
1316 | int rc, old_pool; | |
1317 | ||
1318 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1319 | if (rc != GNUTLS_E_SUCCESS) |
1320 | { | |
1321 | DEBUG(D_tls) { | |
1322 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1323 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1324 | else | |
1325 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1326 | gnutls_strerror(rc), rc); | |
1327 | }; | |
1328 | return 0; | |
1329 | } | |
1330 | ||
17c76198 PP |
1331 | if (sni_type != GNUTLS_NAME_DNS) |
1332 | { | |
1333 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1334 | return 0; | |
1335 | } | |
44bbabb5 | 1336 | |
17c76198 PP |
1337 | /* We now have a UTF-8 string in sni_name */ |
1338 | old_pool = store_pool; | |
1339 | store_pool = POOL_PERM; | |
1340 | state->received_sni = string_copyn(US sni_name, data_len); | |
1341 | store_pool = old_pool; | |
1342 | ||
1343 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1344 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1345 | |
1346 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1347 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1348 | ||
1349 | if (!state->trigger_sni_changes) | |
1350 | return 0; | |
1351 | ||
1352 | rc = tls_expand_session_files(state); | |
1353 | if (rc != OK) | |
1354 | { | |
1355 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1356 | been offered. The best we can do now is abort. */ | |
1357 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1358 | } | |
1359 | ||
1365611d PP |
1360 | rc = tls_set_remaining_x509(state); |
1361 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1362 | ||
1363 | return 0; | |
059ec3d9 PH |
1364 | } |
1365 | ||
1366 | ||
1367 | ||
17c76198 PP |
1368 | |
1369 | /* ------------------------------------------------------------------------ */ | |
1370 | /* Exported functions */ | |
1371 | ||
1372 | ||
1373 | ||
1374 | ||
059ec3d9 PH |
1375 | /************************************************* |
1376 | * Start a TLS session in a server * | |
1377 | *************************************************/ | |
1378 | ||
1379 | /* This is called when Exim is running as a server, after having received | |
1380 | the STARTTLS command. It must respond to that command, and then negotiate | |
1381 | a TLS session. | |
1382 | ||
1383 | Arguments: | |
83da1223 | 1384 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1385 | |
1386 | Returns: OK on success | |
1387 | DEFER for errors before the start of the negotiation | |
1388 | FAIL for errors during the negotation; the server can't | |
1389 | continue running. | |
1390 | */ | |
1391 | ||
1392 | int | |
17c76198 | 1393 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1394 | { |
1395 | int rc; | |
7199e1ee | 1396 | const char *error; |
17c76198 | 1397 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1398 | |
1399 | /* Check for previous activation */ | |
817d9f57 | 1400 | if (tls_in.active >= 0) |
059ec3d9 | 1401 | { |
17c76198 | 1402 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1403 | smtp_printf("554 Already in TLS\r\n"); |
1404 | return FAIL; | |
1405 | } | |
1406 | ||
1407 | /* Initialize the library. If it fails, it will already have logged the error | |
1408 | and sent an SMTP response. */ | |
1409 | ||
17c76198 | 1410 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1411 | |
17c76198 PP |
1412 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1413 | NULL, tls_verify_certificates, tls_crl, | |
1414 | require_ciphers, &state); | |
059ec3d9 PH |
1415 | if (rc != OK) return rc; |
1416 | ||
059ec3d9 PH |
1417 | /* If this is a host for which certificate verification is mandatory or |
1418 | optional, set up appropriately. */ | |
1419 | ||
059ec3d9 | 1420 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 PP |
1421 | { |
1422 | DEBUG(D_tls) debug_printf("TLS: a client certificate will be required.\n"); | |
1423 | state->verify_requirement = VERIFY_REQUIRED; | |
1424 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1425 | } | |
059ec3d9 | 1426 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 PP |
1427 | { |
1428 | DEBUG(D_tls) debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
1429 | state->verify_requirement = VERIFY_OPTIONAL; | |
1430 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1431 | } | |
1432 | else | |
1433 | { | |
1434 | DEBUG(D_tls) debug_printf("TLS: a client certificate will not be requested.\n"); | |
1435 | state->verify_requirement = VERIFY_NONE; | |
1436 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1437 | } | |
059ec3d9 | 1438 | |
17c76198 PP |
1439 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1440 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1441 | |
17c76198 PP |
1442 | gnutls_handshake_set_post_client_hello_function(state->session, |
1443 | exim_sni_handling_cb); | |
059ec3d9 PH |
1444 | |
1445 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1446 | on connection, where outputting anything now upsets the clients and tends to | |
1447 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1448 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1449 | mode, the fflush() happens when smtp_getc() is called. */ | |
1450 | ||
817d9f57 | 1451 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1452 | { |
1453 | smtp_printf("220 TLS go ahead\r\n"); | |
817d9f57 | 1454 | fflush(smtp_out); /*XXX JGH */ |
059ec3d9 PH |
1455 | } |
1456 | ||
1457 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1458 | that the GnuTLS library doesn't. */ | |
1459 | ||
17c76198 PP |
1460 | gnutls_transport_set_ptr2(state->session, |
1461 | (gnutls_transport_ptr)fileno(smtp_in), | |
1462 | (gnutls_transport_ptr)fileno(smtp_out)); | |
1463 | state->fd_in = fileno(smtp_in); | |
1464 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1465 | |
1466 | sigalrm_seen = FALSE; | |
1467 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 PP |
1468 | do |
1469 | { | |
1470 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1471 | } while ((rc == GNUTLS_E_AGAIN) || |
1472 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1473 | alarm(0); |
1474 | ||
17c76198 | 1475 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1476 | { |
17c76198 PP |
1477 | tls_error(US"gnutls_handshake", |
1478 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
059ec3d9 PH |
1479 | /* It seems that, except in the case of a timeout, we have to close the |
1480 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1481 | until the server times out. */ | |
1482 | ||
1483 | if (!sigalrm_seen) | |
1484 | { | |
f1e894f3 PH |
1485 | (void)fclose(smtp_out); |
1486 | (void)fclose(smtp_in); | |
059ec3d9 PH |
1487 | } |
1488 | ||
1489 | return FAIL; | |
1490 | } | |
1491 | ||
1492 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1493 | ||
17c76198 PP |
1494 | /* Verify after the fact */ |
1495 | ||
1496 | if (state->verify_requirement != VERIFY_NONE) | |
059ec3d9 | 1497 | { |
17c76198 PP |
1498 | if (!verify_certificate(state, &error)) |
1499 | { | |
1500 | if (state->verify_requirement == VERIFY_OPTIONAL) | |
1501 | { | |
1502 | DEBUG(D_tls) | |
1503 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1504 | error); | |
1505 | } | |
1506 | else | |
1507 | { | |
1508 | tls_error(US"certificate verification failed", error, NULL); | |
1509 | return FAIL; | |
1510 | } | |
1511 | } | |
059ec3d9 PH |
1512 | } |
1513 | ||
17c76198 PP |
1514 | /* Figure out peer DN, and if authenticated, etc. */ |
1515 | ||
1516 | rc = peer_status(state); | |
1517 | if (rc != OK) return rc; | |
1518 | ||
1519 | /* Sets various Exim expansion variables; always safe within server */ | |
1520 | ||
817d9f57 | 1521 | extract_exim_vars_from_tls_state(state, TRUE); |
059ec3d9 PH |
1522 | |
1523 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1524 | and initialize appropriately. */ | |
1525 | ||
17c76198 | 1526 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1527 | |
1528 | receive_getc = tls_getc; | |
1529 | receive_ungetc = tls_ungetc; | |
1530 | receive_feof = tls_feof; | |
1531 | receive_ferror = tls_ferror; | |
58eb016e | 1532 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1533 | |
059ec3d9 PH |
1534 | return OK; |
1535 | } | |
1536 | ||
1537 | ||
1538 | ||
1539 | ||
1540 | /************************************************* | |
1541 | * Start a TLS session in a client * | |
1542 | *************************************************/ | |
1543 | ||
1544 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1545 | ||
1546 | Arguments: | |
1547 | fd the fd of the connection | |
1548 | host connected host (for messages) | |
83da1223 | 1549 | addr the first address (not used) |
059ec3d9 PH |
1550 | certificate certificate file |
1551 | privatekey private key file | |
3f0945ff | 1552 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1553 | verify_certs file for certificate verify |
1554 | verify_crl CRL for verify | |
83da1223 | 1555 | require_ciphers list of allowed ciphers or NULL |
54c90be1 | 1556 | dh_min_bits minimum number of bits acceptable in server's DH prime |
059ec3d9 PH |
1557 | timeout startup timeout |
1558 | ||
1559 | Returns: OK/DEFER/FAIL (because using common functions), | |
1560 | but for a client, DEFER and FAIL have the same meaning | |
1561 | */ | |
1562 | ||
1563 | int | |
17c76198 | 1564 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1565 | address_item *addr ARG_UNUSED, |
17c76198 PP |
1566 | uschar *certificate, uschar *privatekey, uschar *sni, |
1567 | uschar *verify_certs, uschar *verify_crl, | |
f5d78688 JH |
1568 | uschar *require_ciphers, |
1569 | #ifdef EXPERIMENTAL_OCSP | |
1570 | uschar *require_ocsp ARG_UNUSED, | |
1571 | #endif | |
1572 | int dh_min_bits, int timeout) | |
059ec3d9 | 1573 | { |
059ec3d9 | 1574 | int rc; |
17c76198 PP |
1575 | const char *error; |
1576 | exim_gnutls_state_st *state = NULL; | |
059ec3d9 | 1577 | |
17c76198 | 1578 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1579 | |
17c76198 PP |
1580 | rc = tls_init(host, certificate, privatekey, |
1581 | sni, verify_certs, verify_crl, require_ciphers, &state); | |
059ec3d9 PH |
1582 | if (rc != OK) return rc; |
1583 | ||
54c90be1 PP |
1584 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) |
1585 | { | |
1586 | DEBUG(D_tls) | |
1587 | debug_printf("WARNING: tls_dh_min_bits far too low, clamping %d up to %d\n", | |
1588 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1589 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1590 | } | |
1591 | ||
1592 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum acceptable bits to %d\n", | |
1593 | dh_min_bits); | |
1594 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
83da1223 | 1595 | |
17c76198 PP |
1596 | if (verify_certs == NULL) |
1597 | { | |
1598 | DEBUG(D_tls) debug_printf("TLS: server certificate verification not required\n"); | |
1599 | state->verify_requirement = VERIFY_NONE; | |
1600 | /* we still ask for it, to log it, etc */ | |
1601 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1602 | } | |
1603 | else | |
1604 | { | |
1605 | DEBUG(D_tls) debug_printf("TLS: server certificate verification required\n"); | |
1606 | state->verify_requirement = VERIFY_REQUIRED; | |
1607 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1608 | } | |
059ec3d9 | 1609 | |
17c76198 PP |
1610 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)fd); |
1611 | state->fd_in = fd; | |
1612 | state->fd_out = fd; | |
059ec3d9 PH |
1613 | |
1614 | /* There doesn't seem to be a built-in timeout on connection. */ | |
1615 | ||
1616 | sigalrm_seen = FALSE; | |
1617 | alarm(timeout); | |
17c76198 PP |
1618 | do |
1619 | { | |
1620 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1621 | } while ((rc == GNUTLS_E_AGAIN) || |
1622 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1623 | alarm(0); |
1624 | ||
4fe99a6c PP |
1625 | if (rc != GNUTLS_E_SUCCESS) |
1626 | return tls_error(US"gnutls_handshake", | |
1627 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
1628 | ||
17c76198 | 1629 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 1630 | |
17c76198 | 1631 | /* Verify late */ |
059ec3d9 | 1632 | |
17c76198 PP |
1633 | if (state->verify_requirement != VERIFY_NONE && |
1634 | !verify_certificate(state, &error)) | |
1635 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 1636 | |
17c76198 | 1637 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 1638 | |
17c76198 PP |
1639 | rc = peer_status(state); |
1640 | if (rc != OK) return rc; | |
059ec3d9 | 1641 | |
4fe99a6c | 1642 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 1643 | |
817d9f57 | 1644 | extract_exim_vars_from_tls_state(state, FALSE); |
059ec3d9 | 1645 | |
059ec3d9 PH |
1646 | return OK; |
1647 | } | |
1648 | ||
1649 | ||
1650 | ||
17c76198 | 1651 | |
059ec3d9 | 1652 | /************************************************* |
17c76198 | 1653 | * Close down a TLS session * |
059ec3d9 PH |
1654 | *************************************************/ |
1655 | ||
17c76198 PP |
1656 | /* This is also called from within a delivery subprocess forked from the |
1657 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1658 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 1659 | |
17c76198 PP |
1660 | Arguments: TRUE if gnutls_bye is to be called |
1661 | Returns: nothing | |
059ec3d9 PH |
1662 | */ |
1663 | ||
17c76198 | 1664 | void |
817d9f57 | 1665 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1666 | { |
817d9f57 | 1667 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1668 | |
389ca47a | 1669 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
1670 | |
1671 | if (shutdown) | |
1672 | { | |
1673 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1674 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
1675 | } | |
1676 | ||
1677 | gnutls_deinit(state->session); | |
1678 | ||
389ca47a | 1679 | state->tlsp->active = -1; |
17c76198 PP |
1680 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
1681 | ||
1682 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
1683 | { | |
1684 | gnutls_global_deinit(); | |
1685 | exim_gnutls_base_init_done = FALSE; | |
1686 | } | |
7199e1ee | 1687 | |
059ec3d9 PH |
1688 | } |
1689 | ||
1690 | ||
1691 | ||
17c76198 | 1692 | |
059ec3d9 PH |
1693 | /************************************************* |
1694 | * TLS version of getc * | |
1695 | *************************************************/ | |
1696 | ||
1697 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1698 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 1699 | Only used by the server-side TLS. |
059ec3d9 | 1700 | |
17c76198 PP |
1701 | This feeds DKIM and should be used for all message-body reads. |
1702 | ||
059ec3d9 PH |
1703 | Arguments: none |
1704 | Returns: the next character or EOF | |
1705 | */ | |
1706 | ||
1707 | int | |
1708 | tls_getc(void) | |
1709 | { | |
817d9f57 | 1710 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 1711 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 1712 | { |
17c76198 | 1713 | ssize_t inbytes; |
059ec3d9 | 1714 | |
17c76198 PP |
1715 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
1716 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
1717 | |
1718 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1719 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
1720 | ssl_xfer_buffer_size); |
1721 | alarm(0); | |
1722 | ||
1723 | /* A zero-byte return appears to mean that the TLS session has been | |
1724 | closed down, not that the socket itself has been closed down. Revert to | |
1725 | non-TLS handling. */ | |
1726 | ||
1727 | if (inbytes == 0) | |
1728 | { | |
1729 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1730 | ||
1731 | receive_getc = smtp_getc; | |
1732 | receive_ungetc = smtp_ungetc; | |
1733 | receive_feof = smtp_feof; | |
1734 | receive_ferror = smtp_ferror; | |
58eb016e | 1735 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1736 | |
17c76198 PP |
1737 | gnutls_deinit(state->session); |
1738 | state->session = NULL; | |
817d9f57 JH |
1739 | state->tlsp->active = -1; |
1740 | state->tlsp->bits = 0; | |
1741 | state->tlsp->certificate_verified = FALSE; | |
1742 | tls_channelbinding_b64 = NULL; /*XXX JGH */ | |
1743 | state->tlsp->cipher = NULL; | |
1744 | state->tlsp->peerdn = NULL; | |
059ec3d9 PH |
1745 | |
1746 | return smtp_getc(); | |
1747 | } | |
1748 | ||
1749 | /* Handle genuine errors */ | |
1750 | ||
1751 | else if (inbytes < 0) | |
1752 | { | |
17c76198 PP |
1753 | record_io_error(state, (int) inbytes, US"recv", NULL); |
1754 | state->xfer_error = 1; | |
059ec3d9 PH |
1755 | return EOF; |
1756 | } | |
80a47a2c | 1757 | #ifndef DISABLE_DKIM |
17c76198 | 1758 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 1759 | #endif |
17c76198 PP |
1760 | state->xfer_buffer_hwm = (int) inbytes; |
1761 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
1762 | } |
1763 | ||
059ec3d9 PH |
1764 | /* Something in the buffer; return next uschar */ |
1765 | ||
17c76198 | 1766 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
1767 | } |
1768 | ||
1769 | ||
1770 | ||
17c76198 | 1771 | |
059ec3d9 PH |
1772 | /************************************************* |
1773 | * Read bytes from TLS channel * | |
1774 | *************************************************/ | |
1775 | ||
17c76198 PP |
1776 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
1777 | then the caller must feed DKIM. | |
817d9f57 | 1778 | |
059ec3d9 PH |
1779 | Arguments: |
1780 | buff buffer of data | |
1781 | len size of buffer | |
1782 | ||
1783 | Returns: the number of bytes read | |
1784 | -1 after a failed read | |
1785 | */ | |
1786 | ||
1787 | int | |
817d9f57 | 1788 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 1789 | { |
817d9f57 | 1790 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 1791 | ssize_t inbytes; |
059ec3d9 | 1792 | |
17c76198 PP |
1793 | if (len > INT_MAX) |
1794 | len = INT_MAX; | |
059ec3d9 | 1795 | |
17c76198 PP |
1796 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
1797 | DEBUG(D_tls) | |
1798 | debug_printf("*** PROBABLY A BUG *** " \ | |
1799 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
1800 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
1801 | ||
1802 | DEBUG(D_tls) | |
1803 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
1804 | state->session, buff, len); | |
1805 | ||
1806 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
1807 | if (inbytes > 0) return inbytes; |
1808 | if (inbytes == 0) | |
1809 | { | |
1810 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1811 | } | |
17c76198 | 1812 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
1813 | |
1814 | return -1; | |
1815 | } | |
1816 | ||
1817 | ||
1818 | ||
17c76198 | 1819 | |
059ec3d9 PH |
1820 | /************************************************* |
1821 | * Write bytes down TLS channel * | |
1822 | *************************************************/ | |
1823 | ||
1824 | /* | |
1825 | Arguments: | |
817d9f57 | 1826 | is_server channel specifier |
059ec3d9 PH |
1827 | buff buffer of data |
1828 | len number of bytes | |
1829 | ||
1830 | Returns: the number of bytes after a successful write, | |
1831 | -1 after a failed write | |
1832 | */ | |
1833 | ||
1834 | int | |
817d9f57 | 1835 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 1836 | { |
17c76198 PP |
1837 | ssize_t outbytes; |
1838 | size_t left = len; | |
817d9f57 | 1839 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1840 | |
17c76198 | 1841 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
1842 | while (left > 0) |
1843 | { | |
17c76198 PP |
1844 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
1845 | buff, left); | |
1846 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 1847 | |
17c76198 | 1848 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
1849 | if (outbytes < 0) |
1850 | { | |
17c76198 | 1851 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
1852 | return -1; |
1853 | } | |
1854 | if (outbytes == 0) | |
1855 | { | |
17c76198 | 1856 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
1857 | return -1; |
1858 | } | |
1859 | ||
1860 | left -= outbytes; | |
1861 | buff += outbytes; | |
1862 | } | |
1863 | ||
17c76198 PP |
1864 | if (len > INT_MAX) |
1865 | { | |
1866 | DEBUG(D_tls) | |
1867 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
1868 | len); | |
1869 | len = INT_MAX; | |
1870 | } | |
1871 | ||
1872 | return (int) len; | |
059ec3d9 PH |
1873 | } |
1874 | ||
1875 | ||
1876 | ||
17c76198 | 1877 | |
059ec3d9 | 1878 | /************************************************* |
17c76198 | 1879 | * Random number generation * |
059ec3d9 PH |
1880 | *************************************************/ |
1881 | ||
17c76198 PP |
1882 | /* Pseudo-random number generation. The result is not expected to be |
1883 | cryptographically strong but not so weak that someone will shoot themselves | |
1884 | in the foot using it as a nonce in input in some email header scheme or | |
1885 | whatever weirdness they'll twist this into. The result should handle fork() | |
1886 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 1887 | |
17c76198 PP |
1888 | Arguments: |
1889 | max range maximum | |
1890 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
1891 | */ |
1892 | ||
af3498d6 | 1893 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
1894 | int |
1895 | vaguely_random_number(int max) | |
059ec3d9 | 1896 | { |
17c76198 PP |
1897 | unsigned int r; |
1898 | int i, needed_len; | |
1899 | uschar *p; | |
1900 | uschar smallbuf[sizeof(r)]; | |
1901 | ||
1902 | if (max <= 1) | |
1903 | return 0; | |
1904 | ||
1905 | needed_len = sizeof(r); | |
1906 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1907 | * asked for a number less than 10. */ | |
1908 | for (r = max, i = 0; r; ++i) | |
1909 | r >>= 1; | |
1910 | i = (i + 7) / 8; | |
1911 | if (i < needed_len) | |
1912 | needed_len = i; | |
1913 | ||
1914 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
1915 | if (i < 0) | |
059ec3d9 | 1916 | { |
17c76198 PP |
1917 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
1918 | return vaguely_random_number_fallback(max); | |
1919 | } | |
1920 | r = 0; | |
1921 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
1922 | { | |
1923 | r *= 256; | |
1924 | r += *p; | |
059ec3d9 PH |
1925 | } |
1926 | ||
17c76198 PP |
1927 | /* We don't particularly care about weighted results; if someone wants |
1928 | * smooth distribution and cares enough then they should submit a patch then. */ | |
1929 | return r % max; | |
059ec3d9 | 1930 | } |
af3498d6 PP |
1931 | #else /* HAVE_GNUTLS_RND */ |
1932 | int | |
1933 | vaguely_random_number(int max) | |
1934 | { | |
1935 | return vaguely_random_number_fallback(max); | |
1936 | } | |
1937 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 1938 | |
36f12725 NM |
1939 | |
1940 | ||
1941 | ||
3375e053 PP |
1942 | /************************************************* |
1943 | * Let tls_require_ciphers be checked at startup * | |
1944 | *************************************************/ | |
1945 | ||
1946 | /* The tls_require_ciphers option, if set, must be something which the | |
1947 | library can parse. | |
1948 | ||
1949 | Returns: NULL on success, or error message | |
1950 | */ | |
1951 | ||
1952 | uschar * | |
1953 | tls_validate_require_cipher(void) | |
1954 | { | |
1955 | int rc; | |
1956 | uschar *expciphers = NULL; | |
1957 | gnutls_priority_t priority_cache; | |
1958 | const char *errpos; | |
1959 | ||
1960 | #define validate_check_rc(Label) do { \ | |
1961 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
1962 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
1963 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
1964 | ||
1965 | if (exim_gnutls_base_init_done) | |
1966 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1967 | "already initialised GnuTLS, Exim developer bug"); | |
1968 | ||
a5f239e4 PP |
1969 | #ifdef HAVE_GNUTLS_PKCS11 |
1970 | if (!gnutls_enable_pkcs11) | |
1971 | { | |
1972 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1973 | validate_check_rc(US"gnutls_pkcs11_init"); | |
1974 | } | |
1975 | #endif | |
3375e053 PP |
1976 | rc = gnutls_global_init(); |
1977 | validate_check_rc(US"gnutls_global_init()"); | |
1978 | exim_gnutls_base_init_done = TRUE; | |
1979 | ||
1980 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1981 | return_deinit(NULL); | |
1982 | ||
1983 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1984 | return_deinit(US"failed to expand tls_require_ciphers"); | |
1985 | ||
1986 | if (!(expciphers && *expciphers)) | |
1987 | return_deinit(NULL); | |
1988 | ||
1989 | DEBUG(D_tls) | |
1990 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1991 | ||
1992 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
1993 | validate_check_rc(string_sprintf( | |
1994 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
1995 | expciphers, errpos - CS expciphers, errpos)); | |
1996 | ||
1997 | #undef return_deinit | |
1998 | #undef validate_check_rc | |
1999 | gnutls_global_deinit(); | |
2000 | ||
2001 | return NULL; | |
2002 | } | |
2003 | ||
2004 | ||
2005 | ||
2006 | ||
36f12725 NM |
2007 | /************************************************* |
2008 | * Report the library versions. * | |
2009 | *************************************************/ | |
2010 | ||
2011 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2012 | ||
2013 | Arguments: a FILE* to print the results to | |
2014 | Returns: nothing | |
2015 | */ | |
2016 | ||
2017 | void | |
2018 | tls_version_report(FILE *f) | |
2019 | { | |
754a0503 PP |
2020 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2021 | " Runtime: %s\n", | |
2022 | LIBGNUTLS_VERSION, | |
2023 | gnutls_check_version(NULL)); | |
36f12725 NM |
2024 | } |
2025 | ||
059ec3d9 | 2026 | /* End of tls-gnu.c */ |