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> | |
059ec3d9 | 42 | |
17c76198 | 43 | /* GnuTLS 2 vs 3 |
059ec3d9 | 44 | |
17c76198 PP |
45 | GnuTLS 3 only: |
46 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 47 | |
17c76198 PP |
48 | Changes: |
49 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
50 | */ | |
059ec3d9 | 51 | |
17c76198 | 52 | /* Local static variables for GnuTLS */ |
059ec3d9 | 53 | |
17c76198 | 54 | /* Values for verify_requirement */ |
059ec3d9 | 55 | |
17c76198 | 56 | enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 57 | |
17c76198 PP |
58 | /* This holds most state for server or client; with this, we can set up an |
59 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
60 | over the TLS variables available for expansion. | |
059ec3d9 | 61 | |
17c76198 PP |
62 | Some of these correspond to variables in globals.c; those variables will |
63 | be set to point to content in one of these instances, as appropriate for | |
64 | the stage of the process lifetime. | |
059ec3d9 | 65 | |
389ca47a | 66 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 67 | */ |
059ec3d9 | 68 | |
17c76198 PP |
69 | typedef struct exim_gnutls_state { |
70 | gnutls_session_t session; | |
71 | gnutls_certificate_credentials_t x509_cred; | |
72 | gnutls_priority_t priority_cache; | |
73 | enum peer_verify_requirement verify_requirement; | |
74 | int fd_in; | |
75 | int fd_out; | |
76 | BOOL peer_cert_verified; | |
77 | BOOL trigger_sni_changes; | |
4fe99a6c | 78 | BOOL have_set_peerdn; |
17c76198 PP |
79 | const struct host_item *host; |
80 | uschar *peerdn; | |
75fe387d | 81 | uschar *ciphersuite; |
17c76198 PP |
82 | uschar *received_sni; |
83 | ||
84 | const uschar *tls_certificate; | |
85 | const uschar *tls_privatekey; | |
86 | const uschar *tls_sni; /* client send only, not received */ | |
87 | const uschar *tls_verify_certificates; | |
88 | const uschar *tls_crl; | |
89 | const uschar *tls_require_ciphers; | |
90 | uschar *exp_tls_certificate; | |
91 | uschar *exp_tls_privatekey; | |
92 | uschar *exp_tls_sni; | |
93 | uschar *exp_tls_verify_certificates; | |
94 | uschar *exp_tls_crl; | |
95 | uschar *exp_tls_require_ciphers; | |
96 | ||
389ca47a | 97 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 98 | |
17c76198 PP |
99 | uschar *xfer_buffer; |
100 | int xfer_buffer_lwm; | |
101 | int xfer_buffer_hwm; | |
102 | int xfer_eof; | |
103 | int xfer_error; | |
17c76198 PP |
104 | } exim_gnutls_state_st; |
105 | ||
106 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 107 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 108 | NULL, NULL, NULL, NULL, |
17c76198 PP |
109 | NULL, NULL, NULL, NULL, NULL, NULL, |
110 | NULL, NULL, NULL, NULL, NULL, NULL, | |
817d9f57 | 111 | NULL, |
17c76198 | 112 | NULL, 0, 0, 0, 0, |
17c76198 | 113 | }; |
83da1223 | 114 | |
17c76198 PP |
115 | /* Not only do we have our own APIs which don't pass around state, assuming |
116 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
117 | for callbacks, or as part of the session, so we have to keep a "this is the | |
118 | context we're currently dealing with" pointer and rely upon being | |
119 | single-threaded to keep from processing data on an inbound TLS connection while | |
120 | talking to another TLS connection for an outbound check. This does mean that | |
121 | there's no way for heart-beats to be responded to, for the duration of the | |
122 | second connection. */ | |
059ec3d9 | 123 | |
17c76198 | 124 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 125 | |
17c76198 PP |
126 | /* dh_params are initialised once within the lifetime of a process using TLS; |
127 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
128 | don't want to repeat this. */ | |
83da1223 | 129 | |
17c76198 | 130 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 131 | |
17c76198 | 132 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 133 | |
17c76198 | 134 | static const int ssl_session_timeout = 200; |
059ec3d9 | 135 | |
17c76198 | 136 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 137 | |
17c76198 | 138 | /* Guard library core initialisation */ |
83da1223 | 139 | |
17c76198 | 140 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 141 | |
059ec3d9 | 142 | |
17c76198 PP |
143 | /* ------------------------------------------------------------------------ */ |
144 | /* macros */ | |
83da1223 | 145 | |
17c76198 | 146 | #define MAX_HOST_LEN 255 |
83da1223 | 147 | |
17c76198 PP |
148 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
149 | the library logging; a value less than 0 disables the calls to set up logging | |
150 | callbacks. */ | |
2c17bb02 | 151 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
17c76198 | 152 | #define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 153 | #endif |
83da1223 | 154 | |
2c17bb02 | 155 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
bba74fc6 | 156 | #define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 157 | #endif |
83da1223 | 158 | |
af3498d6 PP |
159 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
160 | can ask for a bit-strength. Without that, we stick to the constant we had | |
161 | before, for now. */ | |
2c17bb02 | 162 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
af3498d6 | 163 | #define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 164 | #endif |
af3498d6 | 165 | |
17c76198 PP |
166 | #define exim_gnutls_err_check(Label) do { \ |
167 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 168 | |
17c76198 | 169 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 170 | |
17c76198 PP |
171 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
172 | #define HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
af3498d6 PP |
173 | #define HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
174 | #define HAVE_GNUTLS_RND | |
17c76198 | 175 | #endif |
83da1223 | 176 | |
af3498d6 PP |
177 | |
178 | ||
179 | ||
180 | /* ------------------------------------------------------------------------ */ | |
181 | /* Callback declarations */ | |
182 | ||
183 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
184 | static void exim_gnutls_logger_cb(int level, const char *message); | |
185 | #endif | |
186 | ||
187 | static int exim_sni_handling_cb(gnutls_session_t session); | |
188 | ||
189 | ||
190 | ||
191 | ||
17c76198 PP |
192 | /* ------------------------------------------------------------------------ */ |
193 | /* Static functions */ | |
059ec3d9 PH |
194 | |
195 | /************************************************* | |
196 | * Handle TLS error * | |
197 | *************************************************/ | |
198 | ||
199 | /* Called from lots of places when errors occur before actually starting to do | |
200 | the TLS handshake, that is, while the session is still in clear. Always returns | |
201 | DEFER for a server and FAIL for a client so that most calls can use "return | |
202 | tls_error(...)" to do this processing and then give an appropriate return. A | |
203 | single function is used for both server and client, because it is called from | |
204 | some shared functions. | |
205 | ||
206 | Argument: | |
207 | prefix text to include in the logged error | |
7199e1ee TF |
208 | msg additional error string (may be NULL) |
209 | usually obtained from gnutls_strerror() | |
17c76198 PP |
210 | host NULL if setting up a server; |
211 | the connected host if setting up a client | |
059ec3d9 PH |
212 | |
213 | Returns: OK/DEFER/FAIL | |
214 | */ | |
215 | ||
216 | static int | |
17c76198 | 217 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 218 | { |
17c76198 PP |
219 | if (host) |
220 | { | |
221 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", | |
222 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); | |
223 | return FAIL; | |
224 | } | |
225 | else | |
059ec3d9 | 226 | { |
7199e1ee | 227 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 228 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
229 | conn_info += 5; |
230 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", | |
17c76198 | 231 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
232 | return DEFER; |
233 | } | |
059ec3d9 PH |
234 | } |
235 | ||
236 | ||
237 | ||
17c76198 | 238 | |
059ec3d9 | 239 | /************************************************* |
17c76198 | 240 | * Deal with logging errors during I/O * |
059ec3d9 PH |
241 | *************************************************/ |
242 | ||
17c76198 | 243 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 244 | |
17c76198 PP |
245 | Argument: |
246 | state the current GnuTLS exim state container | |
247 | rc the GnuTLS error code, or 0 if it's a local error | |
248 | when text identifying read or write | |
249 | text local error text when ec is 0 | |
059ec3d9 | 250 | |
17c76198 | 251 | Returns: nothing |
059ec3d9 PH |
252 | */ |
253 | ||
17c76198 PP |
254 | static void |
255 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 256 | { |
17c76198 | 257 | const char *msg; |
059ec3d9 | 258 | |
17c76198 PP |
259 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
260 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
261 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
262 | else | |
263 | msg = gnutls_strerror(rc); | |
059ec3d9 | 264 | |
17c76198 PP |
265 | tls_error(when, msg, state->host); |
266 | } | |
059ec3d9 | 267 | |
059ec3d9 | 268 | |
059ec3d9 | 269 | |
059ec3d9 | 270 | |
17c76198 PP |
271 | /************************************************* |
272 | * Set various Exim expansion vars * | |
273 | *************************************************/ | |
059ec3d9 | 274 | |
17c76198 PP |
275 | /* We set various Exim global variables from the state, once a session has |
276 | been established. With TLS callouts, may need to change this to stack | |
277 | variables, or just re-call it with the server state after client callout | |
278 | has finished. | |
059ec3d9 | 279 | |
17c76198 PP |
280 | Make sure anything set here is inset in tls_getc(). |
281 | ||
282 | Sets: | |
283 | tls_active fd | |
284 | tls_bits strength indicator | |
285 | tls_certificate_verified bool indicator | |
286 | tls_channelbinding_b64 for some SASL mechanisms | |
287 | tls_cipher a string | |
288 | tls_peerdn a string | |
289 | tls_sni a (UTF-8) string | |
17c76198 PP |
290 | |
291 | Argument: | |
292 | state the relevant exim_gnutls_state_st * | |
293 | */ | |
294 | ||
295 | static void | |
817d9f57 | 296 | extract_exim_vars_from_tls_state(exim_gnutls_state_st *state, BOOL is_server) |
17c76198 | 297 | { |
17c76198 | 298 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
299 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
300 | int old_pool; | |
301 | int rc; | |
302 | gnutls_datum_t channel; | |
303 | #endif | |
304 | ||
817d9f57 | 305 | state->tlsp->active = state->fd_out; |
17c76198 PP |
306 | |
307 | cipher = gnutls_cipher_get(state->session); | |
308 | /* returns size in "bytes" */ | |
817d9f57 | 309 | state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 310 | |
817d9f57 | 311 | state->tlsp->cipher = state->ciphersuite; |
17c76198 | 312 | |
817d9f57 | 313 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 314 | |
817d9f57 | 315 | state->tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 316 | |
17c76198 PP |
317 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
318 | only available for use for authenticators while this TLS session is running. */ | |
319 | ||
320 | tls_channelbinding_b64 = NULL; | |
321 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
322 | channel.data = NULL; | |
323 | channel.size = 0; | |
324 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
325 | if (rc) { | |
326 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
327 | } else { | |
328 | old_pool = store_pool; | |
329 | store_pool = POOL_PERM; | |
330 | tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); | |
331 | store_pool = old_pool; | |
332 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
333 | } | |
334 | #endif | |
335 | ||
817d9f57 JH |
336 | state->tlsp->peerdn = state->peerdn; |
337 | state->tlsp->sni = state->received_sni; | |
059ec3d9 PH |
338 | } |
339 | ||
340 | ||
341 | ||
17c76198 | 342 | |
059ec3d9 | 343 | /************************************************* |
575643cd | 344 | * Setup up DH parameters * |
059ec3d9 PH |
345 | *************************************************/ |
346 | ||
575643cd | 347 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
348 | be re-generated every so often, depending on security policy. What we do is to |
349 | keep these parameters in a file in the spool directory. If the file does not | |
350 | exist, we generate them. This means that it is easy to cause a regeneration. | |
351 | ||
352 | The new file is written as a temporary file and renamed, so that an incomplete | |
353 | file is never present. If two processes both compute some new parameters, you | |
354 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
355 | prevent this. | |
356 | ||
059ec3d9 PH |
357 | Returns: OK/DEFER/FAIL |
358 | */ | |
359 | ||
360 | static int | |
17c76198 | 361 | init_server_dh(void) |
059ec3d9 | 362 | { |
17c76198 PP |
363 | int fd, rc; |
364 | unsigned int dh_bits; | |
b5aea5e1 | 365 | gnutls_datum m; |
a799883d PP |
366 | uschar filename_buf[PATH_MAX]; |
367 | uschar *filename = NULL; | |
17c76198 | 368 | size_t sz; |
a799883d PP |
369 | uschar *exp_tls_dhparam; |
370 | BOOL use_file_in_spool = FALSE; | |
371 | BOOL use_fixed_file = FALSE; | |
17c76198 | 372 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 373 | |
17c76198 | 374 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 375 | |
17c76198 PP |
376 | rc = gnutls_dh_params_init(&dh_server_params); |
377 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 378 | |
a799883d PP |
379 | m.data = NULL; |
380 | m.size = 0; | |
381 | ||
382 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
383 | return DEFER; | |
384 | ||
385 | if (!exp_tls_dhparam) | |
386 | { | |
387 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
388 | m.data = US std_dh_prime_default(); | |
389 | m.size = Ustrlen(m.data); | |
390 | } | |
391 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
392 | use_file_in_spool = TRUE; | |
393 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
394 | { | |
395 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
396 | return OK; | |
397 | } | |
398 | else if (exp_tls_dhparam[0] != '/') | |
399 | { | |
400 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
401 | if (m.data == NULL) | |
402 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
403 | m.size = Ustrlen(m.data); | |
404 | } | |
405 | else | |
406 | { | |
407 | use_fixed_file = TRUE; | |
408 | filename = exp_tls_dhparam; | |
409 | } | |
410 | ||
411 | if (m.data) | |
412 | { | |
413 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
414 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
415 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
416 | return OK; | |
417 | } | |
418 | ||
af3498d6 PP |
419 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
420 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
421 | different filename and ensure we have sufficient bits. */ |
422 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
423 | if (!dh_bits) | |
424 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 425 | DEBUG(D_tls) |
b34fc30c | 426 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
427 | dh_bits); |
428 | #else | |
429 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
430 | DEBUG(D_tls) | |
431 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
432 | dh_bits); | |
433 | #endif | |
059ec3d9 | 434 | |
3375e053 PP |
435 | /* Some clients have hard-coded limits. */ |
436 | if (dh_bits > tls_dh_max_bits) | |
437 | { | |
438 | DEBUG(D_tls) | |
439 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
440 | tls_dh_max_bits); | |
441 | dh_bits = tls_dh_max_bits; | |
442 | } | |
443 | ||
a799883d PP |
444 | if (use_file_in_spool) |
445 | { | |
446 | if (!string_format(filename_buf, sizeof(filename_buf), | |
447 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
448 | return tls_error(US"overlong filename", NULL, NULL); | |
449 | filename = filename_buf; | |
450 | } | |
059ec3d9 | 451 | |
b5aea5e1 | 452 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 453 | parameters. */ |
059ec3d9 PH |
454 | |
455 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 456 | if (fd >= 0) |
059ec3d9 | 457 | { |
b5aea5e1 | 458 | struct stat statbuf; |
17c76198 PP |
459 | FILE *fp; |
460 | int saved_errno; | |
461 | ||
462 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
463 | { | |
464 | saved_errno = errno; | |
465 | (void)close(fd); | |
466 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
467 | } | |
468 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
469 | { |
470 | (void)close(fd); | |
17c76198 PP |
471 | return tls_error(US"TLS cache not a file", NULL, NULL); |
472 | } | |
473 | fp = fdopen(fd, "rb"); | |
474 | if (!fp) | |
475 | { | |
476 | saved_errno = errno; | |
477 | (void)close(fd); | |
478 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
479 | strerror(saved_errno), NULL); | |
b5aea5e1 | 480 | } |
059ec3d9 | 481 | |
b5aea5e1 PH |
482 | m.size = statbuf.st_size; |
483 | m.data = malloc(m.size); | |
484 | if (m.data == NULL) | |
17c76198 PP |
485 | { |
486 | fclose(fp); | |
487 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
488 | } | |
489 | sz = fread(m.data, m.size, 1, fp); | |
490 | if (!sz) | |
491 | { | |
492 | saved_errno = errno; | |
493 | fclose(fp); | |
494 | free(m.data); | |
495 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
496 | } | |
497 | fclose(fp); | |
b5aea5e1 | 498 | |
17c76198 | 499 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 500 | free(m.data); |
17c76198 PP |
501 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
502 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
503 | } |
504 | ||
505 | /* If the file does not exist, fall through to compute new data and cache it. | |
506 | If there was any other opening error, it is serious. */ | |
507 | ||
182ad5cf PH |
508 | else if (errno == ENOENT) |
509 | { | |
17c76198 | 510 | rc = -1; |
182ad5cf | 511 | DEBUG(D_tls) |
17c76198 | 512 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
513 | } |
514 | else | |
17c76198 PP |
515 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
516 | NULL, NULL); | |
b5aea5e1 PH |
517 | |
518 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
519 | is not useful. One particular case of this is when upgrading from an older | |
520 | release of Exim in which the data was stored in a different format. We don't | |
521 | try to be clever and support both formats; we just regenerate new data in this | |
522 | case. */ | |
523 | ||
17c76198 | 524 | if (rc < 0) |
b5aea5e1 | 525 | { |
17c76198 | 526 | uschar *temp_fn; |
201f5254 | 527 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 528 | |
17c76198 PP |
529 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
530 | return tls_error(US"Filename too long to generate replacement", | |
531 | CS filename, NULL); | |
059ec3d9 | 532 | |
17c76198 PP |
533 | temp_fn = string_copy(US "%s.XXXXXXX"); |
534 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 535 | if (fd < 0) |
17c76198 | 536 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
537 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
538 | ||
201f5254 PP |
539 | /* GnuTLS overshoots! |
540 | * If we ask for 2236, we might get 2237 or more. | |
541 | * But there's no way to ask GnuTLS how many bits there really are. | |
542 | * We can ask how many bits were used in a TLS session, but that's it! | |
543 | * The prime itself is hidden behind too much abstraction. | |
544 | * So we ask for less, and proceed on a wing and a prayer. | |
545 | * First attempt, subtracted 3 for 2233 and got 2240. | |
546 | */ | |
cae6e576 | 547 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
548 | { |
549 | dh_bits_gen = dh_bits - 10; | |
550 | DEBUG(D_tls) | |
551 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
552 | dh_bits_gen); | |
553 | } | |
554 | ||
555 | DEBUG(D_tls) | |
556 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
557 | dh_bits_gen); | |
558 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
559 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
560 | ||
561 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
562 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
563 | sample apps handle this. */ | |
564 | ||
565 | sz = 0; | |
566 | m.data = NULL; | |
567 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
568 | m.data, &sz); | |
569 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
570 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
571 | m.size = sz; | |
b5aea5e1 PH |
572 | m.data = malloc(m.size); |
573 | if (m.data == NULL) | |
17c76198 | 574 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
1f00591e | 575 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 576 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 577 | m.data, &sz); |
17c76198 PP |
578 | if (rc != GNUTLS_E_SUCCESS) |
579 | { | |
580 | free(m.data); | |
581 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
582 | } | |
1f00591e | 583 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 584 | |
17c76198 PP |
585 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
586 | if (sz != m.size) | |
587 | { | |
588 | free(m.data); | |
589 | return tls_error(US"TLS cache write D-H params failed", | |
590 | strerror(errno), NULL); | |
591 | } | |
b5aea5e1 | 592 | free(m.data); |
17c76198 PP |
593 | sz = write_to_fd_buf(fd, US"\n", 1); |
594 | if (sz != 1) | |
595 | return tls_error(US"TLS cache write D-H params final newline failed", | |
596 | strerror(errno), NULL); | |
597 | ||
598 | rc = close(fd); | |
599 | if (rc) | |
600 | return tls_error(US"TLS cache write close() failed", | |
601 | strerror(errno), NULL); | |
059ec3d9 | 602 | |
17c76198 PP |
603 | if (Urename(temp_fn, filename) < 0) |
604 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
605 | temp_fn, filename), strerror(errno), NULL); | |
059ec3d9 | 606 | |
17c76198 | 607 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
608 | } |
609 | ||
17c76198 | 610 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
611 | return OK; |
612 | } | |
613 | ||
614 | ||
615 | ||
616 | ||
617 | /************************************************* | |
17c76198 | 618 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
619 | *************************************************/ |
620 | ||
17c76198 PP |
621 | /* Called from both server and client code, via tls_init(), and also from |
622 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
623 | ||
624 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
625 | ||
626 | The callback should not call us unless state->trigger_sni_changes is true, | |
627 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
628 | |
629 | Arguments: | |
17c76198 | 630 | state exim_gnutls_state_st * |
059ec3d9 PH |
631 | |
632 | Returns: OK/DEFER/FAIL | |
633 | */ | |
634 | ||
635 | static int | |
17c76198 | 636 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 637 | { |
1365611d | 638 | struct stat statbuf; |
059ec3d9 | 639 | int rc; |
17c76198 PP |
640 | const host_item *host = state->host; /* macro should be reconsidered? */ |
641 | uschar *saved_tls_certificate = NULL; | |
642 | uschar *saved_tls_privatekey = NULL; | |
643 | uschar *saved_tls_verify_certificates = NULL; | |
644 | uschar *saved_tls_crl = NULL; | |
645 | int cert_count; | |
646 | ||
647 | /* We check for tls_sni *before* expansion. */ | |
648 | if (!state->host) | |
649 | { | |
650 | if (!state->received_sni) | |
651 | { | |
d9b2312b JH |
652 | if (state->tls_certificate && |
653 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
654 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
655 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
656 | )) | |
17c76198 PP |
657 | { |
658 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
659 | state->trigger_sni_changes = TRUE; | |
660 | } | |
661 | } | |
662 | else | |
663 | { | |
1365611d | 664 | /* useful for debugging */ |
17c76198 PP |
665 | saved_tls_certificate = state->exp_tls_certificate; |
666 | saved_tls_privatekey = state->exp_tls_privatekey; | |
667 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
668 | saved_tls_crl = state->exp_tls_crl; | |
669 | } | |
670 | } | |
059ec3d9 | 671 | |
1365611d PP |
672 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
673 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
674 | ||
17c76198 PP |
675 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
676 | state members, assuming consistent naming; and expand_check() returns | |
677 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 678 | |
17c76198 PP |
679 | /* check if we at least have a certificate, before doing expensive |
680 | D-H generation. */ | |
059ec3d9 | 681 | |
17c76198 PP |
682 | if (!expand_check_tlsvar(tls_certificate)) |
683 | return DEFER; | |
059ec3d9 | 684 | |
17c76198 | 685 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 686 | |
17c76198 PP |
687 | if ((state->exp_tls_certificate == NULL) || |
688 | (*state->exp_tls_certificate == '\0')) | |
689 | { | |
690 | if (state->host == NULL) | |
691 | return tls_error(US"no TLS server certificate is specified", NULL, NULL); | |
692 | else | |
693 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
694 | } | |
059ec3d9 | 695 | |
17c76198 | 696 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
697 | return DEFER; |
698 | ||
17c76198 PP |
699 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
700 | ||
701 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 702 | { |
17c76198 PP |
703 | state->tls_privatekey = state->tls_certificate; |
704 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 705 | } |
c91535f3 | 706 | |
059ec3d9 | 707 | |
17c76198 | 708 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
709 | { |
710 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
711 | state->exp_tls_certificate, state->exp_tls_privatekey); |
712 | ||
713 | if (state->received_sni) | |
de365ded | 714 | { |
17c76198 PP |
715 | if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && |
716 | (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) | |
717 | { | |
b34fc30c | 718 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
719 | } |
720 | else | |
721 | { | |
b34fc30c | 722 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 723 | } |
8e669ac1 | 724 | } |
059ec3d9 | 725 | |
1365611d PP |
726 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
727 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
728 | GNUTLS_X509_FMT_PEM); | |
729 | exim_gnutls_err_check( | |
730 | string_sprintf("cert/key setup: cert=%s key=%s", | |
731 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
732 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 733 | } /* tls_certificate */ |
059ec3d9 PH |
734 | |
735 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is | |
736 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
737 | error message is provided. However, if we just refrain from setting anything up | |
738 | in that case, certificate verification fails, which seems to be the correct | |
739 | behaviour. */ | |
740 | ||
17c76198 | 741 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 742 | { |
17c76198 | 743 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 744 | return DEFER; |
17c76198 PP |
745 | if (state->tls_crl && *state->tls_crl) |
746 | if (!expand_check_tlsvar(tls_crl)) | |
747 | return DEFER; | |
059ec3d9 | 748 | |
1365611d PP |
749 | if (!(state->exp_tls_verify_certificates && |
750 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
751 | { |
752 | DEBUG(D_tls) | |
1365611d PP |
753 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
754 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 755 | return OK; |
b34fc30c | 756 | } |
1365611d | 757 | } |
83e2f8a2 PP |
758 | else |
759 | { | |
760 | DEBUG(D_tls) | |
761 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
762 | return OK; | |
763 | } | |
17c76198 | 764 | |
1365611d PP |
765 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
766 | { | |
767 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
768 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
769 | strerror(errno)); | |
770 | return DEFER; | |
771 | } | |
17c76198 | 772 | |
619b2b25 PP |
773 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
774 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
775 | other weirdness. The thing we really want to check is that it's not a | |
776 | directory, since while OpenSSL supports that, GnuTLS does not. | |
777 | So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ | |
778 | if (S_ISDIR(statbuf.st_mode)) | |
1365611d PP |
779 | { |
780 | DEBUG(D_tls) | |
619b2b25 PP |
781 | debug_printf("verify certificates path is a dir: \"%s\"\n", |
782 | state->exp_tls_verify_certificates); | |
1365611d | 783 | log_write(0, LOG_MAIN|LOG_PANIC, |
619b2b25 | 784 | "tls_verify_certificates \"%s\" is a directory", |
1365611d PP |
785 | state->exp_tls_verify_certificates); |
786 | return DEFER; | |
787 | } | |
059ec3d9 | 788 | |
1365611d PP |
789 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
790 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 791 | |
1365611d PP |
792 | if (statbuf.st_size == 0) |
793 | { | |
794 | DEBUG(D_tls) | |
795 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
796 | return OK; | |
797 | } | |
059ec3d9 | 798 | |
1365611d PP |
799 | cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, |
800 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
801 | if (cert_count < 0) | |
802 | { | |
803 | rc = cert_count; | |
804 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); | |
805 | } | |
806 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 807 | |
5c8cda3a PP |
808 | if (state->tls_crl && *state->tls_crl && |
809 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 810 | { |
5c8cda3a PP |
811 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
812 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
813 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
814 | if (cert_count < 0) | |
1365611d | 815 | { |
5c8cda3a | 816 | rc = cert_count; |
1365611d PP |
817 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
818 | } | |
5c8cda3a | 819 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 820 | } |
059ec3d9 | 821 | |
059ec3d9 PH |
822 | return OK; |
823 | } | |
824 | ||
825 | ||
826 | ||
827 | ||
1365611d PP |
828 | /************************************************* |
829 | * Set X.509 state variables * | |
830 | *************************************************/ | |
831 | ||
832 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
833 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
834 | structure. Which means various other non-re-expanded pieces of state | |
835 | need to be re-set in the new struct, so the setting logic is pulled | |
836 | out to this. | |
837 | ||
838 | Arguments: | |
839 | state exim_gnutls_state_st * | |
840 | ||
841 | Returns: OK/DEFER/FAIL | |
842 | */ | |
843 | ||
844 | static int | |
845 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
846 | { | |
847 | int rc; | |
848 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
849 | ||
850 | /* Create D-H parameters, or read them from the cache file. This function does | |
851 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
852 | client-side params. */ | |
853 | ||
854 | if (!state->host) | |
855 | { | |
856 | if (!dh_server_params) | |
857 | { | |
858 | rc = init_server_dh(); | |
859 | if (rc != OK) return rc; | |
860 | } | |
861 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
862 | } | |
863 | ||
864 | /* Link the credentials to the session. */ | |
865 | ||
866 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
867 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
868 | ||
869 | return OK; | |
870 | } | |
871 | ||
059ec3d9 | 872 | /************************************************* |
17c76198 | 873 | * Initialize for GnuTLS * |
059ec3d9 PH |
874 | *************************************************/ |
875 | ||
17c76198 PP |
876 | /* Called from both server and client code. In the case of a server, errors |
877 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
878 | |
879 | Arguments: | |
17c76198 PP |
880 | host connected host, if client; NULL if server |
881 | certificate certificate file | |
882 | privatekey private key file | |
883 | sni TLS SNI to send, sometimes when client; else NULL | |
884 | cas CA certs file | |
885 | crl CRL file | |
886 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 887 | caller_state returned state-info structure |
059ec3d9 | 888 | |
17c76198 | 889 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
890 | */ |
891 | ||
17c76198 PP |
892 | static int |
893 | tls_init( | |
894 | const host_item *host, | |
895 | const uschar *certificate, | |
896 | const uschar *privatekey, | |
897 | const uschar *sni, | |
898 | const uschar *cas, | |
899 | const uschar *crl, | |
900 | const uschar *require_ciphers, | |
901 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 902 | { |
17c76198 PP |
903 | exim_gnutls_state_st *state; |
904 | int rc; | |
905 | size_t sz; | |
906 | const char *errpos; | |
907 | uschar *p; | |
908 | BOOL want_default_priorities; | |
909 | ||
910 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 911 | { |
17c76198 PP |
912 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
913 | ||
914 | rc = gnutls_global_init(); | |
915 | exim_gnutls_err_check(US"gnutls_global_init"); | |
916 | ||
917 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
918 | DEBUG(D_tls) | |
059ec3d9 | 919 | { |
17c76198 PP |
920 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
921 | /* arbitrarily chosen level; bump upto 9 for more */ | |
922 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 923 | } |
17c76198 PP |
924 | #endif |
925 | ||
926 | exim_gnutls_base_init_done = TRUE; | |
059ec3d9 | 927 | } |
059ec3d9 | 928 | |
17c76198 PP |
929 | if (host) |
930 | { | |
931 | state = &state_client; | |
932 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 933 | state->tlsp = &tls_out; |
17c76198 PP |
934 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
935 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
936 | } | |
937 | else | |
938 | { | |
939 | state = &state_server; | |
940 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 941 | state->tlsp = &tls_in; |
17c76198 PP |
942 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
943 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
944 | } | |
945 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 946 | |
17c76198 | 947 | state->host = host; |
059ec3d9 | 948 | |
17c76198 PP |
949 | state->tls_certificate = certificate; |
950 | state->tls_privatekey = privatekey; | |
5779e6aa | 951 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
952 | state->tls_sni = sni; |
953 | state->tls_verify_certificates = cas; | |
954 | state->tls_crl = crl; | |
059ec3d9 | 955 | |
17c76198 PP |
956 | /* This handles the variables that might get re-expanded after TLS SNI; |
957 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 958 | |
17c76198 PP |
959 | DEBUG(D_tls) |
960 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
961 | rc = tls_expand_session_files(state); | |
962 | if (rc != OK) return rc; | |
059ec3d9 | 963 | |
1365611d PP |
964 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
965 | requires a new structure afterwards. */ | |
83da1223 | 966 | |
1365611d PP |
967 | rc = tls_set_remaining_x509(state); |
968 | if (rc != OK) return rc; | |
83da1223 | 969 | |
17c76198 PP |
970 | /* set SNI in client, only */ |
971 | if (host) | |
972 | { | |
d9b2312b | 973 | if (!expand_check(state->tlsp->sni, "tls_out_sni", &state->exp_tls_sni)) |
17c76198 PP |
974 | return DEFER; |
975 | if (state->exp_tls_sni && *state->exp_tls_sni) | |
976 | { | |
977 | DEBUG(D_tls) | |
978 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); | |
979 | sz = Ustrlen(state->exp_tls_sni); | |
980 | rc = gnutls_server_name_set(state->session, | |
981 | GNUTLS_NAME_DNS, state->exp_tls_sni, sz); | |
982 | exim_gnutls_err_check(US"gnutls_server_name_set"); | |
983 | } | |
984 | } | |
985 | else if (state->tls_sni) | |
986 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
987 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 988 | |
17c76198 PP |
989 | /* This is the priority string support, |
990 | http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html | |
991 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. | |
992 | This was backwards incompatible, but means Exim no longer needs to track | |
993 | all algorithms and provide string forms for them. */ | |
83da1223 | 994 | |
17c76198 | 995 | want_default_priorities = TRUE; |
83da1223 | 996 | |
17c76198 | 997 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 998 | { |
17c76198 PP |
999 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1000 | return DEFER; | |
1001 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1002 | { |
17c76198 PP |
1003 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1004 | state->exp_tls_require_ciphers); | |
1005 | ||
1006 | rc = gnutls_priority_init(&state->priority_cache, | |
1007 | CS state->exp_tls_require_ciphers, &errpos); | |
1008 | want_default_priorities = FALSE; | |
1009 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1010 | } |
1011 | } | |
17c76198 PP |
1012 | if (want_default_priorities) |
1013 | { | |
83e2f8a2 PP |
1014 | DEBUG(D_tls) |
1015 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1016 | exim_default_gnutls_priority); | |
17c76198 PP |
1017 | rc = gnutls_priority_init(&state->priority_cache, |
1018 | exim_default_gnutls_priority, &errpos); | |
1019 | p = US exim_default_gnutls_priority; | |
1020 | } | |
83da1223 | 1021 | |
17c76198 PP |
1022 | exim_gnutls_err_check(string_sprintf( |
1023 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1024 | p, errpos - CS p, errpos)); | |
1025 | ||
1026 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1027 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1028 | ||
1029 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1030 | ||
1031 | /* Reduce security in favour of increased compatibility, if the admin | |
1032 | decides to make that trade-off. */ | |
1033 | if (gnutls_compat_mode) | |
83da1223 | 1034 | { |
17c76198 PP |
1035 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1036 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1037 | gnutls_session_enable_compatibility_mode(state->session); | |
1038 | #else | |
1039 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1040 | #endif | |
83da1223 PH |
1041 | } |
1042 | ||
17c76198 | 1043 | *caller_state = state; |
17c76198 | 1044 | return OK; |
83da1223 PH |
1045 | } |
1046 | ||
1047 | ||
1048 | ||
1049 | ||
059ec3d9 | 1050 | /************************************************* |
17c76198 | 1051 | * Extract peer information * |
059ec3d9 PH |
1052 | *************************************************/ |
1053 | ||
17c76198 | 1054 | /* Called from both server and client code. |
4fe99a6c PP |
1055 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1056 | and we use that to detect double-calls. | |
059ec3d9 | 1057 | |
75fe387d PP |
1058 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1059 | for logging in the server side, but for the client side, we log after teardown | |
1060 | in src/deliver.c. While the session is up, we can twist about states and | |
1061 | repoint tls_* globals, but those variables used for logging or other variable | |
1062 | expansion that happens _after_ delivery need to have a longer life-time. | |
1063 | ||
1064 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1065 | doing this more than once per generation of a state context. We set them in | |
1066 | the state context, and repoint tls_* to them. After the state goes away, the | |
1067 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1068 | ||
1069 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1070 | don't apply. | |
1071 | ||
059ec3d9 | 1072 | Arguments: |
17c76198 | 1073 | state exim_gnutls_state_st * |
059ec3d9 | 1074 | |
17c76198 | 1075 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1076 | */ |
1077 | ||
17c76198 PP |
1078 | static int |
1079 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1080 | { |
75fe387d | 1081 | uschar cipherbuf[256]; |
17c76198 | 1082 | const gnutls_datum *cert_list; |
75fe387d | 1083 | int old_pool, rc; |
17c76198 | 1084 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1085 | gnutls_protocol_t protocol; |
1086 | gnutls_cipher_algorithm_t cipher; | |
1087 | gnutls_kx_algorithm_t kx; | |
1088 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1089 | gnutls_certificate_type_t ct; |
1090 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1091 | uschar *p, *dn_buf; |
17c76198 | 1092 | size_t sz; |
059ec3d9 | 1093 | |
4fe99a6c | 1094 | if (state->have_set_peerdn) |
17c76198 | 1095 | return OK; |
4fe99a6c | 1096 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1097 | |
4fe99a6c | 1098 | state->peerdn = NULL; |
059ec3d9 | 1099 | |
4fe99a6c PP |
1100 | /* tls_cipher */ |
1101 | cipher = gnutls_cipher_get(state->session); | |
1102 | protocol = gnutls_protocol_get_version(state->session); | |
1103 | mac = gnutls_mac_get(state->session); | |
1104 | kx = gnutls_kx_get(state->session); | |
1105 | ||
75fe387d | 1106 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1107 | "%s:%s:%d", |
1108 | gnutls_protocol_get_name(protocol), | |
1109 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1110 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1111 | ||
1112 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1113 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1114 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1115 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1116 | if (isspace(*p)) |
1117 | *p = '-'; | |
75fe387d PP |
1118 | old_pool = store_pool; |
1119 | store_pool = POOL_PERM; | |
1120 | state->ciphersuite = string_copy(cipherbuf); | |
1121 | store_pool = old_pool; | |
817d9f57 | 1122 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1123 | |
1124 | /* tls_peerdn */ | |
17c76198 | 1125 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1126 | |
17c76198 PP |
1127 | if (cert_list == NULL || cert_list_size == 0) |
1128 | { | |
17c76198 PP |
1129 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1130 | cert_list, cert_list_size); | |
1131 | if (state->verify_requirement == VERIFY_REQUIRED) | |
1132 | return tls_error(US"certificate verification failed", | |
1133 | "no certificate received from peer", state->host); | |
1134 | return OK; | |
1135 | } | |
059ec3d9 | 1136 | |
17c76198 PP |
1137 | ct = gnutls_certificate_type_get(state->session); |
1138 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1139 | { |
17c76198 | 1140 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1141 | DEBUG(D_tls) |
1142 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
1143 | if (state->verify_requirement == VERIFY_REQUIRED) | |
1144 | return tls_error(US"certificate verification not possible, unhandled type", | |
1145 | ctn, state->host); | |
1146 | return OK; | |
83da1223 | 1147 | } |
059ec3d9 | 1148 | |
17c76198 PP |
1149 | #define exim_gnutls_peer_err(Label) do { \ |
1150 | if (rc != GNUTLS_E_SUCCESS) { \ | |
1151 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \ | |
1152 | if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \ | |
1153 | return OK; } } while (0) | |
1154 | ||
1155 | rc = gnutls_x509_crt_init(&crt); | |
1156 | exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)"); | |
1157 | ||
1158 | rc = gnutls_x509_crt_import(crt, &cert_list[0], GNUTLS_X509_FMT_DER); | |
1159 | exim_gnutls_peer_err(US"failed to import certificate [gnutls_x509_crt_import(cert 0)]"); | |
1160 | sz = 0; | |
1161 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1162 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1163 | { |
17c76198 PP |
1164 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1165 | return FAIL; /* should not happen */ | |
059ec3d9 | 1166 | } |
17c76198 PP |
1167 | dn_buf = store_get_perm(sz); |
1168 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1169 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
1170 | state->peerdn = dn_buf; | |
1171 | ||
1172 | return OK; | |
1173 | #undef exim_gnutls_peer_err | |
1174 | } | |
059ec3d9 | 1175 | |
059ec3d9 | 1176 | |
059ec3d9 | 1177 | |
059ec3d9 | 1178 | |
17c76198 PP |
1179 | /************************************************* |
1180 | * Verify peer certificate * | |
1181 | *************************************************/ | |
059ec3d9 | 1182 | |
17c76198 PP |
1183 | /* Called from both server and client code. |
1184 | *Should* be using a callback registered with | |
1185 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1186 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1187 | |
17c76198 PP |
1188 | Arguments: |
1189 | state exim_gnutls_state_st * | |
1190 | error where to put an error message | |
059ec3d9 | 1191 | |
17c76198 PP |
1192 | Returns: |
1193 | FALSE if the session should be rejected | |
1194 | TRUE if the cert is okay or we just don't care | |
1195 | */ | |
059ec3d9 | 1196 | |
17c76198 PP |
1197 | static BOOL |
1198 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1199 | { | |
1200 | int rc; | |
1201 | unsigned int verify; | |
1202 | ||
1203 | *error = NULL; | |
1204 | ||
1205 | rc = peer_status(state); | |
1206 | if (rc != OK) | |
e6060e2c | 1207 | { |
17c76198 PP |
1208 | verify = GNUTLS_CERT_INVALID; |
1209 | *error = "not supplied"; | |
1210 | } | |
1211 | else | |
1212 | { | |
1213 | rc = gnutls_certificate_verify_peers2(state->session, &verify); | |
e6060e2c NM |
1214 | } |
1215 | ||
17c76198 PP |
1216 | /* Handle the result of verification. INVALID seems to be set as well |
1217 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1218 | |
17c76198 PP |
1219 | if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) |
1220 | { | |
1221 | state->peer_cert_verified = FALSE; | |
1222 | if (*error == NULL) | |
1223 | *error = ((verify & GNUTLS_CERT_REVOKED) != 0) ? "revoked" : "invalid"; | |
059ec3d9 | 1224 | |
17c76198 PP |
1225 | DEBUG(D_tls) |
1226 | debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", | |
4fe99a6c | 1227 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1228 | |
17c76198 PP |
1229 | if (state->verify_requirement == VERIFY_REQUIRED) |
1230 | { | |
1231 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1232 | return FALSE; | |
1233 | } | |
1234 | DEBUG(D_tls) | |
4789da3a | 1235 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 PP |
1236 | } |
1237 | else | |
1238 | { | |
1239 | state->peer_cert_verified = TRUE; | |
4fe99a6c PP |
1240 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", |
1241 | state->peerdn ? state->peerdn : US"<unset>"); | |
17c76198 | 1242 | } |
059ec3d9 | 1243 | |
817d9f57 | 1244 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1245 | |
17c76198 PP |
1246 | return TRUE; |
1247 | } | |
059ec3d9 | 1248 | |
17c76198 PP |
1249 | |
1250 | ||
1251 | ||
1252 | /* ------------------------------------------------------------------------ */ | |
1253 | /* Callbacks */ | |
1254 | ||
1255 | /* Logging function which can be registered with | |
1256 | * gnutls_global_set_log_function() | |
1257 | * gnutls_global_set_log_level() 0..9 | |
1258 | */ | |
af3498d6 | 1259 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1260 | static void |
17c76198 | 1261 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1262 | { |
8c79eebf PP |
1263 | size_t len = strlen(message); |
1264 | if (len < 1) | |
1265 | { | |
1266 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1267 | return; | |
1268 | } | |
1269 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1270 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1271 | } |
af3498d6 | 1272 | #endif |
059ec3d9 | 1273 | |
059ec3d9 | 1274 | |
17c76198 PP |
1275 | /* Called after client hello, should handle SNI work. |
1276 | This will always set tls_sni (state->received_sni) if available, | |
1277 | and may trigger presenting different certificates, | |
1278 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1279 | |
17c76198 PP |
1280 | Should be registered with |
1281 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1282 | |
17c76198 PP |
1283 | "This callback must return 0 on success or a gnutls error code to terminate the |
1284 | handshake.". | |
059ec3d9 | 1285 | |
17c76198 PP |
1286 | For inability to get SNI information, we return 0. |
1287 | We only return non-zero if re-setup failed. | |
817d9f57 | 1288 | Only used for server-side TLS. |
17c76198 | 1289 | */ |
44bbabb5 | 1290 | |
17c76198 PP |
1291 | static int |
1292 | exim_sni_handling_cb(gnutls_session_t session) | |
1293 | { | |
1294 | char sni_name[MAX_HOST_LEN]; | |
1295 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1296 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1297 | unsigned int sni_type; |
1298 | int rc, old_pool; | |
1299 | ||
1300 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1301 | if (rc != GNUTLS_E_SUCCESS) |
1302 | { | |
1303 | DEBUG(D_tls) { | |
1304 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1305 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1306 | else | |
1307 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1308 | gnutls_strerror(rc), rc); | |
1309 | }; | |
1310 | return 0; | |
1311 | } | |
1312 | ||
17c76198 PP |
1313 | if (sni_type != GNUTLS_NAME_DNS) |
1314 | { | |
1315 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1316 | return 0; | |
1317 | } | |
44bbabb5 | 1318 | |
17c76198 PP |
1319 | /* We now have a UTF-8 string in sni_name */ |
1320 | old_pool = store_pool; | |
1321 | store_pool = POOL_PERM; | |
1322 | state->received_sni = string_copyn(US sni_name, data_len); | |
1323 | store_pool = old_pool; | |
1324 | ||
1325 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1326 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1327 | |
1328 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1329 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1330 | ||
1331 | if (!state->trigger_sni_changes) | |
1332 | return 0; | |
1333 | ||
1334 | rc = tls_expand_session_files(state); | |
1335 | if (rc != OK) | |
1336 | { | |
1337 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1338 | been offered. The best we can do now is abort. */ | |
1339 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1340 | } | |
1341 | ||
1365611d PP |
1342 | rc = tls_set_remaining_x509(state); |
1343 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1344 | ||
1345 | return 0; | |
059ec3d9 PH |
1346 | } |
1347 | ||
1348 | ||
1349 | ||
17c76198 PP |
1350 | |
1351 | /* ------------------------------------------------------------------------ */ | |
1352 | /* Exported functions */ | |
1353 | ||
1354 | ||
1355 | ||
1356 | ||
059ec3d9 PH |
1357 | /************************************************* |
1358 | * Start a TLS session in a server * | |
1359 | *************************************************/ | |
1360 | ||
1361 | /* This is called when Exim is running as a server, after having received | |
1362 | the STARTTLS command. It must respond to that command, and then negotiate | |
1363 | a TLS session. | |
1364 | ||
1365 | Arguments: | |
83da1223 | 1366 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1367 | |
1368 | Returns: OK on success | |
1369 | DEFER for errors before the start of the negotiation | |
1370 | FAIL for errors during the negotation; the server can't | |
1371 | continue running. | |
1372 | */ | |
1373 | ||
1374 | int | |
17c76198 | 1375 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1376 | { |
1377 | int rc; | |
7199e1ee | 1378 | const char *error; |
17c76198 | 1379 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1380 | |
1381 | /* Check for previous activation */ | |
817d9f57 | 1382 | if (tls_in.active >= 0) |
059ec3d9 | 1383 | { |
17c76198 | 1384 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1385 | smtp_printf("554 Already in TLS\r\n"); |
1386 | return FAIL; | |
1387 | } | |
1388 | ||
1389 | /* Initialize the library. If it fails, it will already have logged the error | |
1390 | and sent an SMTP response. */ | |
1391 | ||
17c76198 | 1392 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1393 | |
17c76198 PP |
1394 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1395 | NULL, tls_verify_certificates, tls_crl, | |
1396 | require_ciphers, &state); | |
059ec3d9 PH |
1397 | if (rc != OK) return rc; |
1398 | ||
059ec3d9 PH |
1399 | /* If this is a host for which certificate verification is mandatory or |
1400 | optional, set up appropriately. */ | |
1401 | ||
059ec3d9 | 1402 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 PP |
1403 | { |
1404 | DEBUG(D_tls) debug_printf("TLS: a client certificate will be required.\n"); | |
1405 | state->verify_requirement = VERIFY_REQUIRED; | |
1406 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1407 | } | |
059ec3d9 | 1408 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 PP |
1409 | { |
1410 | DEBUG(D_tls) debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
1411 | state->verify_requirement = VERIFY_OPTIONAL; | |
1412 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1413 | } | |
1414 | else | |
1415 | { | |
1416 | DEBUG(D_tls) debug_printf("TLS: a client certificate will not be requested.\n"); | |
1417 | state->verify_requirement = VERIFY_NONE; | |
1418 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1419 | } | |
059ec3d9 | 1420 | |
17c76198 PP |
1421 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1422 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1423 | |
17c76198 PP |
1424 | gnutls_handshake_set_post_client_hello_function(state->session, |
1425 | exim_sni_handling_cb); | |
059ec3d9 PH |
1426 | |
1427 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1428 | on connection, where outputting anything now upsets the clients and tends to | |
1429 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1430 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1431 | mode, the fflush() happens when smtp_getc() is called. */ | |
1432 | ||
817d9f57 | 1433 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1434 | { |
1435 | smtp_printf("220 TLS go ahead\r\n"); | |
817d9f57 | 1436 | fflush(smtp_out); /*XXX JGH */ |
059ec3d9 PH |
1437 | } |
1438 | ||
1439 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1440 | that the GnuTLS library doesn't. */ | |
1441 | ||
17c76198 PP |
1442 | gnutls_transport_set_ptr2(state->session, |
1443 | (gnutls_transport_ptr)fileno(smtp_in), | |
1444 | (gnutls_transport_ptr)fileno(smtp_out)); | |
1445 | state->fd_in = fileno(smtp_in); | |
1446 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1447 | |
1448 | sigalrm_seen = FALSE; | |
1449 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 PP |
1450 | do |
1451 | { | |
1452 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1453 | } while ((rc == GNUTLS_E_AGAIN) || |
1454 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1455 | alarm(0); |
1456 | ||
17c76198 | 1457 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1458 | { |
17c76198 PP |
1459 | tls_error(US"gnutls_handshake", |
1460 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
059ec3d9 PH |
1461 | /* It seems that, except in the case of a timeout, we have to close the |
1462 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1463 | until the server times out. */ | |
1464 | ||
1465 | if (!sigalrm_seen) | |
1466 | { | |
f1e894f3 PH |
1467 | (void)fclose(smtp_out); |
1468 | (void)fclose(smtp_in); | |
059ec3d9 PH |
1469 | } |
1470 | ||
1471 | return FAIL; | |
1472 | } | |
1473 | ||
1474 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1475 | ||
17c76198 PP |
1476 | /* Verify after the fact */ |
1477 | ||
1478 | if (state->verify_requirement != VERIFY_NONE) | |
059ec3d9 | 1479 | { |
17c76198 PP |
1480 | if (!verify_certificate(state, &error)) |
1481 | { | |
1482 | if (state->verify_requirement == VERIFY_OPTIONAL) | |
1483 | { | |
1484 | DEBUG(D_tls) | |
1485 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1486 | error); | |
1487 | } | |
1488 | else | |
1489 | { | |
1490 | tls_error(US"certificate verification failed", error, NULL); | |
1491 | return FAIL; | |
1492 | } | |
1493 | } | |
059ec3d9 PH |
1494 | } |
1495 | ||
17c76198 PP |
1496 | /* Figure out peer DN, and if authenticated, etc. */ |
1497 | ||
1498 | rc = peer_status(state); | |
1499 | if (rc != OK) return rc; | |
1500 | ||
1501 | /* Sets various Exim expansion variables; always safe within server */ | |
1502 | ||
817d9f57 | 1503 | extract_exim_vars_from_tls_state(state, TRUE); |
059ec3d9 PH |
1504 | |
1505 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1506 | and initialize appropriately. */ | |
1507 | ||
17c76198 | 1508 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1509 | |
1510 | receive_getc = tls_getc; | |
1511 | receive_ungetc = tls_ungetc; | |
1512 | receive_feof = tls_feof; | |
1513 | receive_ferror = tls_ferror; | |
58eb016e | 1514 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1515 | |
059ec3d9 PH |
1516 | return OK; |
1517 | } | |
1518 | ||
1519 | ||
1520 | ||
1521 | ||
1522 | /************************************************* | |
1523 | * Start a TLS session in a client * | |
1524 | *************************************************/ | |
1525 | ||
1526 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1527 | ||
1528 | Arguments: | |
1529 | fd the fd of the connection | |
1530 | host connected host (for messages) | |
83da1223 | 1531 | addr the first address (not used) |
17c76198 | 1532 | dhparam DH parameter file (ignored, we're a client) |
059ec3d9 PH |
1533 | certificate certificate file |
1534 | privatekey private key file | |
3f0945ff | 1535 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1536 | verify_certs file for certificate verify |
1537 | verify_crl CRL for verify | |
83da1223 | 1538 | require_ciphers list of allowed ciphers or NULL |
54c90be1 | 1539 | dh_min_bits minimum number of bits acceptable in server's DH prime |
059ec3d9 PH |
1540 | timeout startup timeout |
1541 | ||
1542 | Returns: OK/DEFER/FAIL (because using common functions), | |
1543 | but for a client, DEFER and FAIL have the same meaning | |
1544 | */ | |
1545 | ||
1546 | int | |
17c76198 PP |
1547 | tls_client_start(int fd, host_item *host, |
1548 | address_item *addr ARG_UNUSED, uschar *dhparam ARG_UNUSED, | |
1549 | uschar *certificate, uschar *privatekey, uschar *sni, | |
1550 | uschar *verify_certs, uschar *verify_crl, | |
54c90be1 | 1551 | uschar *require_ciphers, int dh_min_bits, int timeout) |
059ec3d9 | 1552 | { |
059ec3d9 | 1553 | int rc; |
17c76198 PP |
1554 | const char *error; |
1555 | exim_gnutls_state_st *state = NULL; | |
059ec3d9 | 1556 | |
17c76198 | 1557 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1558 | |
17c76198 PP |
1559 | rc = tls_init(host, certificate, privatekey, |
1560 | sni, verify_certs, verify_crl, require_ciphers, &state); | |
059ec3d9 PH |
1561 | if (rc != OK) return rc; |
1562 | ||
54c90be1 PP |
1563 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) |
1564 | { | |
1565 | DEBUG(D_tls) | |
1566 | debug_printf("WARNING: tls_dh_min_bits far too low, clamping %d up to %d\n", | |
1567 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1568 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1569 | } | |
1570 | ||
1571 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum acceptable bits to %d\n", | |
1572 | dh_min_bits); | |
1573 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
83da1223 | 1574 | |
17c76198 PP |
1575 | if (verify_certs == NULL) |
1576 | { | |
1577 | DEBUG(D_tls) debug_printf("TLS: server certificate verification not required\n"); | |
1578 | state->verify_requirement = VERIFY_NONE; | |
1579 | /* we still ask for it, to log it, etc */ | |
1580 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1581 | } | |
1582 | else | |
1583 | { | |
1584 | DEBUG(D_tls) debug_printf("TLS: server certificate verification required\n"); | |
1585 | state->verify_requirement = VERIFY_REQUIRED; | |
1586 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1587 | } | |
059ec3d9 | 1588 | |
17c76198 PP |
1589 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)fd); |
1590 | state->fd_in = fd; | |
1591 | state->fd_out = fd; | |
059ec3d9 PH |
1592 | |
1593 | /* There doesn't seem to be a built-in timeout on connection. */ | |
1594 | ||
1595 | sigalrm_seen = FALSE; | |
1596 | alarm(timeout); | |
17c76198 PP |
1597 | do |
1598 | { | |
1599 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1600 | } while ((rc == GNUTLS_E_AGAIN) || |
1601 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1602 | alarm(0); |
1603 | ||
4fe99a6c PP |
1604 | if (rc != GNUTLS_E_SUCCESS) |
1605 | return tls_error(US"gnutls_handshake", | |
1606 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
1607 | ||
17c76198 | 1608 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 1609 | |
17c76198 | 1610 | /* Verify late */ |
059ec3d9 | 1611 | |
17c76198 PP |
1612 | if (state->verify_requirement != VERIFY_NONE && |
1613 | !verify_certificate(state, &error)) | |
1614 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 1615 | |
17c76198 | 1616 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 1617 | |
17c76198 PP |
1618 | rc = peer_status(state); |
1619 | if (rc != OK) return rc; | |
059ec3d9 | 1620 | |
4fe99a6c | 1621 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 1622 | |
817d9f57 | 1623 | extract_exim_vars_from_tls_state(state, FALSE); |
059ec3d9 | 1624 | |
059ec3d9 PH |
1625 | return OK; |
1626 | } | |
1627 | ||
1628 | ||
1629 | ||
17c76198 | 1630 | |
059ec3d9 | 1631 | /************************************************* |
17c76198 | 1632 | * Close down a TLS session * |
059ec3d9 PH |
1633 | *************************************************/ |
1634 | ||
17c76198 PP |
1635 | /* This is also called from within a delivery subprocess forked from the |
1636 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1637 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 1638 | |
17c76198 PP |
1639 | Arguments: TRUE if gnutls_bye is to be called |
1640 | Returns: nothing | |
059ec3d9 PH |
1641 | */ |
1642 | ||
17c76198 | 1643 | void |
817d9f57 | 1644 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1645 | { |
817d9f57 | 1646 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1647 | |
389ca47a | 1648 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
1649 | |
1650 | if (shutdown) | |
1651 | { | |
1652 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1653 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
1654 | } | |
1655 | ||
1656 | gnutls_deinit(state->session); | |
1657 | ||
389ca47a | 1658 | state->tlsp->active = -1; |
17c76198 PP |
1659 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
1660 | ||
1661 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
1662 | { | |
1663 | gnutls_global_deinit(); | |
1664 | exim_gnutls_base_init_done = FALSE; | |
1665 | } | |
7199e1ee | 1666 | |
059ec3d9 PH |
1667 | } |
1668 | ||
1669 | ||
1670 | ||
17c76198 | 1671 | |
059ec3d9 PH |
1672 | /************************************************* |
1673 | * TLS version of getc * | |
1674 | *************************************************/ | |
1675 | ||
1676 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1677 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 1678 | Only used by the server-side TLS. |
059ec3d9 | 1679 | |
17c76198 PP |
1680 | This feeds DKIM and should be used for all message-body reads. |
1681 | ||
059ec3d9 PH |
1682 | Arguments: none |
1683 | Returns: the next character or EOF | |
1684 | */ | |
1685 | ||
1686 | int | |
1687 | tls_getc(void) | |
1688 | { | |
817d9f57 | 1689 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 1690 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 1691 | { |
17c76198 | 1692 | ssize_t inbytes; |
059ec3d9 | 1693 | |
17c76198 PP |
1694 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
1695 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
1696 | |
1697 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1698 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
1699 | ssl_xfer_buffer_size); |
1700 | alarm(0); | |
1701 | ||
1702 | /* A zero-byte return appears to mean that the TLS session has been | |
1703 | closed down, not that the socket itself has been closed down. Revert to | |
1704 | non-TLS handling. */ | |
1705 | ||
1706 | if (inbytes == 0) | |
1707 | { | |
1708 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1709 | ||
1710 | receive_getc = smtp_getc; | |
1711 | receive_ungetc = smtp_ungetc; | |
1712 | receive_feof = smtp_feof; | |
1713 | receive_ferror = smtp_ferror; | |
58eb016e | 1714 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1715 | |
17c76198 PP |
1716 | gnutls_deinit(state->session); |
1717 | state->session = NULL; | |
817d9f57 JH |
1718 | state->tlsp->active = -1; |
1719 | state->tlsp->bits = 0; | |
1720 | state->tlsp->certificate_verified = FALSE; | |
1721 | tls_channelbinding_b64 = NULL; /*XXX JGH */ | |
1722 | state->tlsp->cipher = NULL; | |
1723 | state->tlsp->peerdn = NULL; | |
059ec3d9 PH |
1724 | |
1725 | return smtp_getc(); | |
1726 | } | |
1727 | ||
1728 | /* Handle genuine errors */ | |
1729 | ||
1730 | else if (inbytes < 0) | |
1731 | { | |
17c76198 PP |
1732 | record_io_error(state, (int) inbytes, US"recv", NULL); |
1733 | state->xfer_error = 1; | |
059ec3d9 PH |
1734 | return EOF; |
1735 | } | |
80a47a2c | 1736 | #ifndef DISABLE_DKIM |
17c76198 | 1737 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 1738 | #endif |
17c76198 PP |
1739 | state->xfer_buffer_hwm = (int) inbytes; |
1740 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
1741 | } |
1742 | ||
059ec3d9 PH |
1743 | /* Something in the buffer; return next uschar */ |
1744 | ||
17c76198 | 1745 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
1746 | } |
1747 | ||
1748 | ||
1749 | ||
17c76198 | 1750 | |
059ec3d9 PH |
1751 | /************************************************* |
1752 | * Read bytes from TLS channel * | |
1753 | *************************************************/ | |
1754 | ||
17c76198 PP |
1755 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
1756 | then the caller must feed DKIM. | |
817d9f57 | 1757 | |
059ec3d9 PH |
1758 | Arguments: |
1759 | buff buffer of data | |
1760 | len size of buffer | |
1761 | ||
1762 | Returns: the number of bytes read | |
1763 | -1 after a failed read | |
1764 | */ | |
1765 | ||
1766 | int | |
817d9f57 | 1767 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 1768 | { |
817d9f57 | 1769 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 1770 | ssize_t inbytes; |
059ec3d9 | 1771 | |
17c76198 PP |
1772 | if (len > INT_MAX) |
1773 | len = INT_MAX; | |
059ec3d9 | 1774 | |
17c76198 PP |
1775 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
1776 | DEBUG(D_tls) | |
1777 | debug_printf("*** PROBABLY A BUG *** " \ | |
1778 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
1779 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
1780 | ||
1781 | DEBUG(D_tls) | |
1782 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
1783 | state->session, buff, len); | |
1784 | ||
1785 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
1786 | if (inbytes > 0) return inbytes; |
1787 | if (inbytes == 0) | |
1788 | { | |
1789 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1790 | } | |
17c76198 | 1791 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
1792 | |
1793 | return -1; | |
1794 | } | |
1795 | ||
1796 | ||
1797 | ||
17c76198 | 1798 | |
059ec3d9 PH |
1799 | /************************************************* |
1800 | * Write bytes down TLS channel * | |
1801 | *************************************************/ | |
1802 | ||
1803 | /* | |
1804 | Arguments: | |
817d9f57 | 1805 | is_server channel specifier |
059ec3d9 PH |
1806 | buff buffer of data |
1807 | len number of bytes | |
1808 | ||
1809 | Returns: the number of bytes after a successful write, | |
1810 | -1 after a failed write | |
1811 | */ | |
1812 | ||
1813 | int | |
817d9f57 | 1814 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 1815 | { |
17c76198 PP |
1816 | ssize_t outbytes; |
1817 | size_t left = len; | |
817d9f57 | 1818 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1819 | |
17c76198 | 1820 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
1821 | while (left > 0) |
1822 | { | |
17c76198 PP |
1823 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
1824 | buff, left); | |
1825 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 1826 | |
17c76198 | 1827 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
1828 | if (outbytes < 0) |
1829 | { | |
17c76198 | 1830 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
1831 | return -1; |
1832 | } | |
1833 | if (outbytes == 0) | |
1834 | { | |
17c76198 | 1835 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
1836 | return -1; |
1837 | } | |
1838 | ||
1839 | left -= outbytes; | |
1840 | buff += outbytes; | |
1841 | } | |
1842 | ||
17c76198 PP |
1843 | if (len > INT_MAX) |
1844 | { | |
1845 | DEBUG(D_tls) | |
1846 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
1847 | len); | |
1848 | len = INT_MAX; | |
1849 | } | |
1850 | ||
1851 | return (int) len; | |
059ec3d9 PH |
1852 | } |
1853 | ||
1854 | ||
1855 | ||
17c76198 | 1856 | |
059ec3d9 | 1857 | /************************************************* |
17c76198 | 1858 | * Random number generation * |
059ec3d9 PH |
1859 | *************************************************/ |
1860 | ||
17c76198 PP |
1861 | /* Pseudo-random number generation. The result is not expected to be |
1862 | cryptographically strong but not so weak that someone will shoot themselves | |
1863 | in the foot using it as a nonce in input in some email header scheme or | |
1864 | whatever weirdness they'll twist this into. The result should handle fork() | |
1865 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 1866 | |
17c76198 PP |
1867 | Arguments: |
1868 | max range maximum | |
1869 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
1870 | */ |
1871 | ||
af3498d6 | 1872 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
1873 | int |
1874 | vaguely_random_number(int max) | |
059ec3d9 | 1875 | { |
17c76198 PP |
1876 | unsigned int r; |
1877 | int i, needed_len; | |
1878 | uschar *p; | |
1879 | uschar smallbuf[sizeof(r)]; | |
1880 | ||
1881 | if (max <= 1) | |
1882 | return 0; | |
1883 | ||
1884 | needed_len = sizeof(r); | |
1885 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1886 | * asked for a number less than 10. */ | |
1887 | for (r = max, i = 0; r; ++i) | |
1888 | r >>= 1; | |
1889 | i = (i + 7) / 8; | |
1890 | if (i < needed_len) | |
1891 | needed_len = i; | |
1892 | ||
1893 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
1894 | if (i < 0) | |
059ec3d9 | 1895 | { |
17c76198 PP |
1896 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
1897 | return vaguely_random_number_fallback(max); | |
1898 | } | |
1899 | r = 0; | |
1900 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
1901 | { | |
1902 | r *= 256; | |
1903 | r += *p; | |
059ec3d9 PH |
1904 | } |
1905 | ||
17c76198 PP |
1906 | /* We don't particularly care about weighted results; if someone wants |
1907 | * smooth distribution and cares enough then they should submit a patch then. */ | |
1908 | return r % max; | |
059ec3d9 | 1909 | } |
af3498d6 PP |
1910 | #else /* HAVE_GNUTLS_RND */ |
1911 | int | |
1912 | vaguely_random_number(int max) | |
1913 | { | |
1914 | return vaguely_random_number_fallback(max); | |
1915 | } | |
1916 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 1917 | |
36f12725 NM |
1918 | |
1919 | ||
1920 | ||
3375e053 PP |
1921 | /************************************************* |
1922 | * Let tls_require_ciphers be checked at startup * | |
1923 | *************************************************/ | |
1924 | ||
1925 | /* The tls_require_ciphers option, if set, must be something which the | |
1926 | library can parse. | |
1927 | ||
1928 | Returns: NULL on success, or error message | |
1929 | */ | |
1930 | ||
1931 | uschar * | |
1932 | tls_validate_require_cipher(void) | |
1933 | { | |
1934 | int rc; | |
1935 | uschar *expciphers = NULL; | |
1936 | gnutls_priority_t priority_cache; | |
1937 | const char *errpos; | |
1938 | ||
1939 | #define validate_check_rc(Label) do { \ | |
1940 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
1941 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
1942 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
1943 | ||
1944 | if (exim_gnutls_base_init_done) | |
1945 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1946 | "already initialised GnuTLS, Exim developer bug"); | |
1947 | ||
1948 | rc = gnutls_global_init(); | |
1949 | validate_check_rc(US"gnutls_global_init()"); | |
1950 | exim_gnutls_base_init_done = TRUE; | |
1951 | ||
1952 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
1953 | return_deinit(NULL); | |
1954 | ||
1955 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
1956 | return_deinit(US"failed to expand tls_require_ciphers"); | |
1957 | ||
1958 | if (!(expciphers && *expciphers)) | |
1959 | return_deinit(NULL); | |
1960 | ||
1961 | DEBUG(D_tls) | |
1962 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
1963 | ||
1964 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
1965 | validate_check_rc(string_sprintf( | |
1966 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
1967 | expciphers, errpos - CS expciphers, errpos)); | |
1968 | ||
1969 | #undef return_deinit | |
1970 | #undef validate_check_rc | |
1971 | gnutls_global_deinit(); | |
1972 | ||
1973 | return NULL; | |
1974 | } | |
1975 | ||
1976 | ||
1977 | ||
1978 | ||
36f12725 NM |
1979 | /************************************************* |
1980 | * Report the library versions. * | |
1981 | *************************************************/ | |
1982 | ||
1983 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
1984 | ||
1985 | Arguments: a FILE* to print the results to | |
1986 | Returns: nothing | |
1987 | */ | |
1988 | ||
1989 | void | |
1990 | tls_version_report(FILE *f) | |
1991 | { | |
754a0503 PP |
1992 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
1993 | " Runtime: %s\n", | |
1994 | LIBGNUTLS_VERSION, | |
1995 | gnutls_check_version(NULL)); | |
36f12725 NM |
1996 | } |
1997 | ||
059ec3d9 | 1998 | /* End of tls-gnu.c */ |