Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
5a66c31b | 5 | /* Copyright (c) University of Cambridge 1995 - 2014 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
17c76198 | 8 | /* Copyright (c) Phil Pennock 2012 */ |
059ec3d9 | 9 | |
17c76198 PP |
10 | /* This file provides TLS/SSL support for Exim using the GnuTLS library, |
11 | one of the available supported implementations. This file is #included into | |
12 | tls.c when USE_GNUTLS has been set. | |
059ec3d9 | 13 | |
17c76198 PP |
14 | The code herein is a revamp of GnuTLS integration using the current APIs; the |
15 | original tls-gnu.c was based on a patch which was contributed by Nikos | |
16 | Mavroyanopoulos. The revamp is partially a rewrite, partially cut&paste as | |
17 | appropriate. | |
059ec3d9 | 18 | |
17c76198 PP |
19 | APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, |
20 | which is not widely deployed by OS vendors. Will note issues below, which may | |
21 | assist in updating the code in the future. Another sources of hints is | |
22 | mod_gnutls for Apache (SNI callback registration and handling). | |
059ec3d9 | 23 | |
17c76198 PP |
24 | Keeping client and server variables more split than before and is currently |
25 | the norm, in anticipation of TLS in ACL callouts. | |
059ec3d9 | 26 | |
17c76198 PP |
27 | I wanted to switch to gnutls_certificate_set_verify_function() so that |
28 | certificate rejection could happen during handshake where it belongs, rather | |
29 | than being dropped afterwards, but that was introduced in 2.10.0 and Debian | |
30 | (6.0.5) is still on 2.8.6. So for now we have to stick with sub-par behaviour. | |
059ec3d9 | 31 | |
17c76198 PP |
32 | (I wasn't looking for libraries quite that old, when updating to get rid of |
33 | compiler warnings of deprecated APIs. If it turns out that a lot of the rest | |
34 | require current GnuTLS, then we'll drop support for the ancient libraries). | |
35 | */ | |
b5aea5e1 | 36 | |
17c76198 PP |
37 | #include <gnutls/gnutls.h> |
38 | /* needed for cert checks in verification and DN extraction: */ | |
39 | #include <gnutls/x509.h> | |
40 | /* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ | |
41 | #include <gnutls/crypto.h> | |
a5f239e4 PP |
42 | /* needed to disable PKCS11 autoload unless requested */ |
43 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
44 | # include <gnutls/pkcs11.h> | |
45 | #endif | |
7e07527a JH |
46 | #if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) |
47 | # warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" | |
48 | # define DISABLE_OCSP | |
49 | #endif | |
50 | ||
f2de3a33 | 51 | #ifndef DISABLE_OCSP |
2b4a568d JH |
52 | # include <gnutls/ocsp.h> |
53 | #endif | |
059ec3d9 | 54 | |
17c76198 | 55 | /* GnuTLS 2 vs 3 |
059ec3d9 | 56 | |
17c76198 PP |
57 | GnuTLS 3 only: |
58 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 59 | |
17c76198 PP |
60 | Changes: |
61 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
62 | */ | |
059ec3d9 | 63 | |
17c76198 | 64 | /* Local static variables for GnuTLS */ |
059ec3d9 | 65 | |
17c76198 | 66 | /* Values for verify_requirement */ |
059ec3d9 | 67 | |
e51c7be2 JH |
68 | enum peer_verify_requirement |
69 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED | |
70 | #ifdef EXPERIMENTAL_CERTNAMES | |
71 | ,VERIFY_WITHHOST | |
72 | #endif | |
73 | }; | |
059ec3d9 | 74 | |
17c76198 PP |
75 | /* This holds most state for server or client; with this, we can set up an |
76 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
77 | over the TLS variables available for expansion. | |
059ec3d9 | 78 | |
17c76198 PP |
79 | Some of these correspond to variables in globals.c; those variables will |
80 | be set to point to content in one of these instances, as appropriate for | |
81 | the stage of the process lifetime. | |
059ec3d9 | 82 | |
389ca47a | 83 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 84 | */ |
059ec3d9 | 85 | |
17c76198 | 86 | typedef struct exim_gnutls_state { |
9d1c15ef | 87 | gnutls_session_t session; |
17c76198 | 88 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 89 | gnutls_priority_t priority_cache; |
17c76198 | 90 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
91 | int fd_in; |
92 | int fd_out; | |
93 | BOOL peer_cert_verified; | |
94 | BOOL trigger_sni_changes; | |
95 | BOOL have_set_peerdn; | |
17c76198 | 96 | const struct host_item *host; |
9d1c15ef JH |
97 | gnutls_x509_crt_t peercert; |
98 | uschar *peerdn; | |
99 | uschar *ciphersuite; | |
100 | uschar *received_sni; | |
17c76198 PP |
101 | |
102 | const uschar *tls_certificate; | |
103 | const uschar *tls_privatekey; | |
104 | const uschar *tls_sni; /* client send only, not received */ | |
105 | const uschar *tls_verify_certificates; | |
106 | const uschar *tls_crl; | |
107 | const uschar *tls_require_ciphers; | |
e51c7be2 | 108 | |
17c76198 PP |
109 | uschar *exp_tls_certificate; |
110 | uschar *exp_tls_privatekey; | |
111 | uschar *exp_tls_sni; | |
112 | uschar *exp_tls_verify_certificates; | |
113 | uschar *exp_tls_crl; | |
114 | uschar *exp_tls_require_ciphers; | |
44662487 | 115 | uschar *exp_tls_ocsp_file; |
e51c7be2 JH |
116 | #ifdef EXPERIMENTAL_CERTNAMES |
117 | uschar *exp_tls_verify_cert_hostnames; | |
118 | #endif | |
17c76198 | 119 | |
389ca47a | 120 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 121 | |
17c76198 PP |
122 | uschar *xfer_buffer; |
123 | int xfer_buffer_lwm; | |
124 | int xfer_buffer_hwm; | |
125 | int xfer_eof; | |
126 | int xfer_error; | |
17c76198 PP |
127 | } exim_gnutls_state_st; |
128 | ||
129 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 130 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 131 | NULL, NULL, NULL, NULL, |
17c76198 | 132 | NULL, NULL, NULL, NULL, NULL, NULL, |
44662487 | 133 | NULL, NULL, NULL, NULL, NULL, NULL, NULL, |
e51c7be2 JH |
134 | #ifdef EXPERIMENTAL_CERTNAMES |
135 | NULL, | |
136 | #endif | |
817d9f57 | 137 | NULL, |
17c76198 | 138 | NULL, 0, 0, 0, 0, |
17c76198 | 139 | }; |
83da1223 | 140 | |
17c76198 PP |
141 | /* Not only do we have our own APIs which don't pass around state, assuming |
142 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
143 | for callbacks, or as part of the session, so we have to keep a "this is the | |
144 | context we're currently dealing with" pointer and rely upon being | |
145 | single-threaded to keep from processing data on an inbound TLS connection while | |
146 | talking to another TLS connection for an outbound check. This does mean that | |
147 | there's no way for heart-beats to be responded to, for the duration of the | |
148 | second connection. */ | |
059ec3d9 | 149 | |
17c76198 | 150 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 151 | |
17c76198 PP |
152 | /* dh_params are initialised once within the lifetime of a process using TLS; |
153 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
154 | don't want to repeat this. */ | |
83da1223 | 155 | |
17c76198 | 156 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 157 | |
17c76198 | 158 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 159 | |
17c76198 | 160 | static const int ssl_session_timeout = 200; |
059ec3d9 | 161 | |
17c76198 | 162 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 163 | |
17c76198 | 164 | /* Guard library core initialisation */ |
83da1223 | 165 | |
17c76198 | 166 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 167 | |
059ec3d9 | 168 | |
17c76198 PP |
169 | /* ------------------------------------------------------------------------ */ |
170 | /* macros */ | |
83da1223 | 171 | |
17c76198 | 172 | #define MAX_HOST_LEN 255 |
83da1223 | 173 | |
17c76198 PP |
174 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
175 | the library logging; a value less than 0 disables the calls to set up logging | |
176 | callbacks. */ | |
2c17bb02 | 177 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
17c76198 | 178 | #define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 179 | #endif |
83da1223 | 180 | |
2c17bb02 | 181 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
bba74fc6 | 182 | #define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 183 | #endif |
83da1223 | 184 | |
af3498d6 PP |
185 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
186 | can ask for a bit-strength. Without that, we stick to the constant we had | |
187 | before, for now. */ | |
2c17bb02 | 188 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
af3498d6 | 189 | #define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 190 | #endif |
af3498d6 | 191 | |
17c76198 PP |
192 | #define exim_gnutls_err_check(Label) do { \ |
193 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 194 | |
17c76198 | 195 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 196 | |
17c76198 | 197 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
198 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
199 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
200 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
201 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
202 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
203 | * isn't available sometimes, so this needs to become a conditional | |
204 | * compilation; the sanest way to deal with this being a problem on | |
205 | * older OSes is to block it in the Local/Makefile with this compiler | |
206 | * definition */ | |
e51c7be2 JH |
207 | # ifndef AVOID_GNUTLS_PKCS11 |
208 | # define HAVE_GNUTLS_PKCS11 | |
209 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 210 | #endif |
83da1223 | 211 | |
af3498d6 PP |
212 | |
213 | ||
214 | ||
215 | /* ------------------------------------------------------------------------ */ | |
216 | /* Callback declarations */ | |
217 | ||
218 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
219 | static void exim_gnutls_logger_cb(int level, const char *message); | |
220 | #endif | |
221 | ||
222 | static int exim_sni_handling_cb(gnutls_session_t session); | |
223 | ||
f2de3a33 | 224 | #ifndef DISABLE_OCSP |
44662487 JH |
225 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
226 | gnutls_datum_t * ocsp_response); | |
227 | #endif | |
af3498d6 PP |
228 | |
229 | ||
230 | ||
17c76198 PP |
231 | /* ------------------------------------------------------------------------ */ |
232 | /* Static functions */ | |
059ec3d9 PH |
233 | |
234 | /************************************************* | |
235 | * Handle TLS error * | |
236 | *************************************************/ | |
237 | ||
238 | /* Called from lots of places when errors occur before actually starting to do | |
239 | the TLS handshake, that is, while the session is still in clear. Always returns | |
240 | DEFER for a server and FAIL for a client so that most calls can use "return | |
241 | tls_error(...)" to do this processing and then give an appropriate return. A | |
242 | single function is used for both server and client, because it is called from | |
243 | some shared functions. | |
244 | ||
245 | Argument: | |
246 | prefix text to include in the logged error | |
7199e1ee TF |
247 | msg additional error string (may be NULL) |
248 | usually obtained from gnutls_strerror() | |
17c76198 PP |
249 | host NULL if setting up a server; |
250 | the connected host if setting up a client | |
059ec3d9 PH |
251 | |
252 | Returns: OK/DEFER/FAIL | |
253 | */ | |
254 | ||
255 | static int | |
17c76198 | 256 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 257 | { |
17c76198 PP |
258 | if (host) |
259 | { | |
260 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", | |
261 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); | |
262 | return FAIL; | |
263 | } | |
264 | else | |
059ec3d9 | 265 | { |
7199e1ee | 266 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 267 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
268 | conn_info += 5; |
269 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", | |
17c76198 | 270 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
271 | return DEFER; |
272 | } | |
059ec3d9 PH |
273 | } |
274 | ||
275 | ||
276 | ||
17c76198 | 277 | |
059ec3d9 | 278 | /************************************************* |
17c76198 | 279 | * Deal with logging errors during I/O * |
059ec3d9 PH |
280 | *************************************************/ |
281 | ||
17c76198 | 282 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 283 | |
17c76198 PP |
284 | Argument: |
285 | state the current GnuTLS exim state container | |
286 | rc the GnuTLS error code, or 0 if it's a local error | |
287 | when text identifying read or write | |
288 | text local error text when ec is 0 | |
059ec3d9 | 289 | |
17c76198 | 290 | Returns: nothing |
059ec3d9 PH |
291 | */ |
292 | ||
17c76198 PP |
293 | static void |
294 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 295 | { |
17c76198 | 296 | const char *msg; |
059ec3d9 | 297 | |
17c76198 PP |
298 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
299 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
300 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
301 | else | |
302 | msg = gnutls_strerror(rc); | |
059ec3d9 | 303 | |
17c76198 PP |
304 | tls_error(when, msg, state->host); |
305 | } | |
059ec3d9 | 306 | |
059ec3d9 | 307 | |
059ec3d9 | 308 | |
059ec3d9 | 309 | |
17c76198 PP |
310 | /************************************************* |
311 | * Set various Exim expansion vars * | |
312 | *************************************************/ | |
059ec3d9 | 313 | |
e51c7be2 JH |
314 | #define exim_gnutls_cert_err(Label) \ |
315 | do \ | |
316 | { \ | |
317 | if (rc != GNUTLS_E_SUCCESS) \ | |
318 | { \ | |
319 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
320 | (Label), gnutls_strerror(rc)); \ | |
321 | return rc; \ | |
322 | } \ | |
323 | } while (0) | |
9d1c15ef JH |
324 | |
325 | static int | |
326 | import_cert(const gnutls_datum * cert, gnutls_x509_crt_t * crtp) | |
327 | { | |
328 | int rc; | |
329 | ||
330 | rc = gnutls_x509_crt_init(crtp); | |
331 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
332 | ||
333 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
334 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
335 | ||
336 | return rc; | |
337 | } | |
338 | ||
339 | #undef exim_gnutls_cert_err | |
340 | ||
341 | ||
17c76198 PP |
342 | /* We set various Exim global variables from the state, once a session has |
343 | been established. With TLS callouts, may need to change this to stack | |
344 | variables, or just re-call it with the server state after client callout | |
345 | has finished. | |
059ec3d9 | 346 | |
9d1c15ef | 347 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
348 | |
349 | Sets: | |
350 | tls_active fd | |
351 | tls_bits strength indicator | |
352 | tls_certificate_verified bool indicator | |
353 | tls_channelbinding_b64 for some SASL mechanisms | |
354 | tls_cipher a string | |
9d1c15ef | 355 | tls_peercert pointer to library internal |
17c76198 PP |
356 | tls_peerdn a string |
357 | tls_sni a (UTF-8) string | |
9d1c15ef | 358 | tls_ourcert pointer to library internal |
17c76198 PP |
359 | |
360 | Argument: | |
361 | state the relevant exim_gnutls_state_st * | |
362 | */ | |
363 | ||
364 | static void | |
9d1c15ef | 365 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 366 | { |
17c76198 | 367 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
368 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
369 | int old_pool; | |
370 | int rc; | |
371 | gnutls_datum_t channel; | |
372 | #endif | |
9d1c15ef | 373 | tls_support * tlsp = state->tlsp; |
17c76198 | 374 | |
9d1c15ef | 375 | tlsp->active = state->fd_out; |
17c76198 PP |
376 | |
377 | cipher = gnutls_cipher_get(state->session); | |
378 | /* returns size in "bytes" */ | |
9d1c15ef | 379 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 380 | |
9d1c15ef | 381 | tlsp->cipher = state->ciphersuite; |
17c76198 | 382 | |
817d9f57 | 383 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 384 | |
9d1c15ef | 385 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 386 | |
17c76198 PP |
387 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
388 | only available for use for authenticators while this TLS session is running. */ | |
389 | ||
390 | tls_channelbinding_b64 = NULL; | |
391 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
392 | channel.data = NULL; | |
393 | channel.size = 0; | |
394 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
395 | if (rc) { | |
396 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
397 | } else { | |
398 | old_pool = store_pool; | |
399 | store_pool = POOL_PERM; | |
400 | tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); | |
401 | store_pool = old_pool; | |
402 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
403 | } | |
404 | #endif | |
405 | ||
9d1c15ef JH |
406 | /* peercert is set in peer_status() */ |
407 | tlsp->peerdn = state->peerdn; | |
408 | tlsp->sni = state->received_sni; | |
409 | ||
410 | /* record our certificate */ | |
411 | { | |
412 | const gnutls_datum * cert = gnutls_certificate_get_ours(state->session); | |
413 | gnutls_x509_crt_t crt; | |
414 | ||
415 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
416 | } | |
059ec3d9 PH |
417 | } |
418 | ||
419 | ||
420 | ||
17c76198 | 421 | |
059ec3d9 | 422 | /************************************************* |
575643cd | 423 | * Setup up DH parameters * |
059ec3d9 PH |
424 | *************************************************/ |
425 | ||
575643cd | 426 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
427 | be re-generated every so often, depending on security policy. What we do is to |
428 | keep these parameters in a file in the spool directory. If the file does not | |
429 | exist, we generate them. This means that it is easy to cause a regeneration. | |
430 | ||
431 | The new file is written as a temporary file and renamed, so that an incomplete | |
432 | file is never present. If two processes both compute some new parameters, you | |
433 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
434 | prevent this. | |
435 | ||
059ec3d9 PH |
436 | Returns: OK/DEFER/FAIL |
437 | */ | |
438 | ||
439 | static int | |
17c76198 | 440 | init_server_dh(void) |
059ec3d9 | 441 | { |
17c76198 PP |
442 | int fd, rc; |
443 | unsigned int dh_bits; | |
b5aea5e1 | 444 | gnutls_datum m; |
a799883d PP |
445 | uschar filename_buf[PATH_MAX]; |
446 | uschar *filename = NULL; | |
17c76198 | 447 | size_t sz; |
a799883d PP |
448 | uschar *exp_tls_dhparam; |
449 | BOOL use_file_in_spool = FALSE; | |
450 | BOOL use_fixed_file = FALSE; | |
17c76198 | 451 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 452 | |
17c76198 | 453 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 454 | |
17c76198 PP |
455 | rc = gnutls_dh_params_init(&dh_server_params); |
456 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 457 | |
a799883d PP |
458 | m.data = NULL; |
459 | m.size = 0; | |
460 | ||
461 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
462 | return DEFER; | |
463 | ||
464 | if (!exp_tls_dhparam) | |
465 | { | |
466 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
467 | m.data = US std_dh_prime_default(); | |
468 | m.size = Ustrlen(m.data); | |
469 | } | |
470 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
471 | use_file_in_spool = TRUE; | |
472 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
473 | { | |
474 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
475 | return OK; | |
476 | } | |
477 | else if (exp_tls_dhparam[0] != '/') | |
478 | { | |
479 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
480 | if (m.data == NULL) | |
481 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
482 | m.size = Ustrlen(m.data); | |
483 | } | |
484 | else | |
485 | { | |
486 | use_fixed_file = TRUE; | |
487 | filename = exp_tls_dhparam; | |
488 | } | |
489 | ||
490 | if (m.data) | |
491 | { | |
492 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
493 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
494 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
495 | return OK; | |
496 | } | |
497 | ||
af3498d6 PP |
498 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
499 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
500 | different filename and ensure we have sufficient bits. */ |
501 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
502 | if (!dh_bits) | |
503 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 504 | DEBUG(D_tls) |
b34fc30c | 505 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
506 | dh_bits); |
507 | #else | |
508 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
509 | DEBUG(D_tls) | |
510 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
511 | dh_bits); | |
512 | #endif | |
059ec3d9 | 513 | |
3375e053 PP |
514 | /* Some clients have hard-coded limits. */ |
515 | if (dh_bits > tls_dh_max_bits) | |
516 | { | |
517 | DEBUG(D_tls) | |
518 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
519 | tls_dh_max_bits); | |
520 | dh_bits = tls_dh_max_bits; | |
521 | } | |
522 | ||
a799883d PP |
523 | if (use_file_in_spool) |
524 | { | |
525 | if (!string_format(filename_buf, sizeof(filename_buf), | |
526 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
527 | return tls_error(US"overlong filename", NULL, NULL); | |
528 | filename = filename_buf; | |
529 | } | |
059ec3d9 | 530 | |
b5aea5e1 | 531 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 532 | parameters. */ |
059ec3d9 PH |
533 | |
534 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 535 | if (fd >= 0) |
059ec3d9 | 536 | { |
b5aea5e1 | 537 | struct stat statbuf; |
17c76198 PP |
538 | FILE *fp; |
539 | int saved_errno; | |
540 | ||
541 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
542 | { | |
543 | saved_errno = errno; | |
544 | (void)close(fd); | |
545 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
546 | } | |
547 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
548 | { |
549 | (void)close(fd); | |
17c76198 PP |
550 | return tls_error(US"TLS cache not a file", NULL, NULL); |
551 | } | |
552 | fp = fdopen(fd, "rb"); | |
553 | if (!fp) | |
554 | { | |
555 | saved_errno = errno; | |
556 | (void)close(fd); | |
557 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
558 | strerror(saved_errno), NULL); | |
b5aea5e1 | 559 | } |
059ec3d9 | 560 | |
b5aea5e1 PH |
561 | m.size = statbuf.st_size; |
562 | m.data = malloc(m.size); | |
563 | if (m.data == NULL) | |
17c76198 PP |
564 | { |
565 | fclose(fp); | |
566 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
567 | } | |
568 | sz = fread(m.data, m.size, 1, fp); | |
569 | if (!sz) | |
570 | { | |
571 | saved_errno = errno; | |
572 | fclose(fp); | |
573 | free(m.data); | |
574 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
575 | } | |
576 | fclose(fp); | |
b5aea5e1 | 577 | |
17c76198 | 578 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 579 | free(m.data); |
17c76198 PP |
580 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
581 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
582 | } |
583 | ||
584 | /* If the file does not exist, fall through to compute new data and cache it. | |
585 | If there was any other opening error, it is serious. */ | |
586 | ||
182ad5cf PH |
587 | else if (errno == ENOENT) |
588 | { | |
17c76198 | 589 | rc = -1; |
182ad5cf | 590 | DEBUG(D_tls) |
17c76198 | 591 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
592 | } |
593 | else | |
17c76198 PP |
594 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
595 | NULL, NULL); | |
b5aea5e1 PH |
596 | |
597 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
598 | is not useful. One particular case of this is when upgrading from an older | |
599 | release of Exim in which the data was stored in a different format. We don't | |
600 | try to be clever and support both formats; we just regenerate new data in this | |
601 | case. */ | |
602 | ||
17c76198 | 603 | if (rc < 0) |
b5aea5e1 | 604 | { |
17c76198 | 605 | uschar *temp_fn; |
201f5254 | 606 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 607 | |
17c76198 PP |
608 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
609 | return tls_error(US"Filename too long to generate replacement", | |
610 | CS filename, NULL); | |
059ec3d9 | 611 | |
17c76198 PP |
612 | temp_fn = string_copy(US "%s.XXXXXXX"); |
613 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 614 | if (fd < 0) |
17c76198 | 615 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
616 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
617 | ||
201f5254 PP |
618 | /* GnuTLS overshoots! |
619 | * If we ask for 2236, we might get 2237 or more. | |
620 | * But there's no way to ask GnuTLS how many bits there really are. | |
621 | * We can ask how many bits were used in a TLS session, but that's it! | |
622 | * The prime itself is hidden behind too much abstraction. | |
623 | * So we ask for less, and proceed on a wing and a prayer. | |
624 | * First attempt, subtracted 3 for 2233 and got 2240. | |
625 | */ | |
cae6e576 | 626 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
627 | { |
628 | dh_bits_gen = dh_bits - 10; | |
629 | DEBUG(D_tls) | |
630 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
631 | dh_bits_gen); | |
632 | } | |
633 | ||
634 | DEBUG(D_tls) | |
635 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
636 | dh_bits_gen); | |
637 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
638 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
639 | ||
640 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
641 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
642 | sample apps handle this. */ | |
643 | ||
644 | sz = 0; | |
645 | m.data = NULL; | |
646 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
647 | m.data, &sz); | |
648 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
649 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
650 | m.size = sz; | |
b5aea5e1 PH |
651 | m.data = malloc(m.size); |
652 | if (m.data == NULL) | |
17c76198 | 653 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
1f00591e | 654 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 655 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 656 | m.data, &sz); |
17c76198 PP |
657 | if (rc != GNUTLS_E_SUCCESS) |
658 | { | |
659 | free(m.data); | |
660 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
661 | } | |
1f00591e | 662 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 663 | |
17c76198 PP |
664 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
665 | if (sz != m.size) | |
666 | { | |
667 | free(m.data); | |
668 | return tls_error(US"TLS cache write D-H params failed", | |
669 | strerror(errno), NULL); | |
670 | } | |
b5aea5e1 | 671 | free(m.data); |
17c76198 PP |
672 | sz = write_to_fd_buf(fd, US"\n", 1); |
673 | if (sz != 1) | |
674 | return tls_error(US"TLS cache write D-H params final newline failed", | |
675 | strerror(errno), NULL); | |
676 | ||
677 | rc = close(fd); | |
678 | if (rc) | |
679 | return tls_error(US"TLS cache write close() failed", | |
680 | strerror(errno), NULL); | |
059ec3d9 | 681 | |
17c76198 PP |
682 | if (Urename(temp_fn, filename) < 0) |
683 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
684 | temp_fn, filename), strerror(errno), NULL); | |
059ec3d9 | 685 | |
17c76198 | 686 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
687 | } |
688 | ||
17c76198 | 689 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
690 | return OK; |
691 | } | |
692 | ||
693 | ||
694 | ||
695 | ||
696 | /************************************************* | |
17c76198 | 697 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
698 | *************************************************/ |
699 | ||
17c76198 PP |
700 | /* Called from both server and client code, via tls_init(), and also from |
701 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
702 | ||
703 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
704 | ||
705 | The callback should not call us unless state->trigger_sni_changes is true, | |
706 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
707 | |
708 | Arguments: | |
17c76198 | 709 | state exim_gnutls_state_st * |
059ec3d9 PH |
710 | |
711 | Returns: OK/DEFER/FAIL | |
712 | */ | |
713 | ||
714 | static int | |
17c76198 | 715 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 716 | { |
1365611d | 717 | struct stat statbuf; |
059ec3d9 | 718 | int rc; |
17c76198 PP |
719 | const host_item *host = state->host; /* macro should be reconsidered? */ |
720 | uschar *saved_tls_certificate = NULL; | |
721 | uschar *saved_tls_privatekey = NULL; | |
722 | uschar *saved_tls_verify_certificates = NULL; | |
723 | uschar *saved_tls_crl = NULL; | |
724 | int cert_count; | |
725 | ||
726 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 727 | if (!host) /* server */ |
17c76198 PP |
728 | { |
729 | if (!state->received_sni) | |
730 | { | |
d9b2312b JH |
731 | if (state->tls_certificate && |
732 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
733 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
734 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
735 | )) | |
17c76198 PP |
736 | { |
737 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
738 | state->trigger_sni_changes = TRUE; | |
739 | } | |
740 | } | |
741 | else | |
742 | { | |
1365611d | 743 | /* useful for debugging */ |
17c76198 PP |
744 | saved_tls_certificate = state->exp_tls_certificate; |
745 | saved_tls_privatekey = state->exp_tls_privatekey; | |
746 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
747 | saved_tls_crl = state->exp_tls_crl; | |
748 | } | |
749 | } | |
059ec3d9 | 750 | |
1365611d PP |
751 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
752 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
753 | ||
17c76198 PP |
754 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
755 | state members, assuming consistent naming; and expand_check() returns | |
756 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 757 | |
17c76198 PP |
758 | /* check if we at least have a certificate, before doing expensive |
759 | D-H generation. */ | |
059ec3d9 | 760 | |
17c76198 PP |
761 | if (!expand_check_tlsvar(tls_certificate)) |
762 | return DEFER; | |
059ec3d9 | 763 | |
17c76198 | 764 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 765 | |
17c76198 PP |
766 | if ((state->exp_tls_certificate == NULL) || |
767 | (*state->exp_tls_certificate == '\0')) | |
768 | { | |
2b4a568d | 769 | if (!host) |
17c76198 PP |
770 | return tls_error(US"no TLS server certificate is specified", NULL, NULL); |
771 | else | |
772 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
773 | } | |
059ec3d9 | 774 | |
17c76198 | 775 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
776 | return DEFER; |
777 | ||
17c76198 PP |
778 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
779 | ||
780 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 781 | { |
17c76198 PP |
782 | state->tls_privatekey = state->tls_certificate; |
783 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 784 | } |
c91535f3 | 785 | |
059ec3d9 | 786 | |
17c76198 | 787 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
788 | { |
789 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
790 | state->exp_tls_certificate, state->exp_tls_privatekey); |
791 | ||
792 | if (state->received_sni) | |
de365ded | 793 | { |
17c76198 PP |
794 | if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && |
795 | (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) | |
796 | { | |
b34fc30c | 797 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
798 | } |
799 | else | |
800 | { | |
b34fc30c | 801 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 802 | } |
8e669ac1 | 803 | } |
059ec3d9 | 804 | |
1365611d PP |
805 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
806 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
807 | GNUTLS_X509_FMT_PEM); | |
808 | exim_gnutls_err_check( | |
809 | string_sprintf("cert/key setup: cert=%s key=%s", | |
810 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
811 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 812 | } /* tls_certificate */ |
059ec3d9 | 813 | |
2b4a568d JH |
814 | |
815 | /* Set the OCSP stapling server info */ | |
816 | ||
f2de3a33 | 817 | #ifndef DISABLE_OCSP |
2b4a568d JH |
818 | if ( !host /* server */ |
819 | && tls_ocsp_file | |
820 | ) | |
821 | { | |
44662487 JH |
822 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", |
823 | &state->exp_tls_ocsp_file)) | |
2b4a568d JH |
824 | return DEFER; |
825 | ||
44662487 JH |
826 | /* Use the full callback method for stapling just to get observability. |
827 | More efficient would be to read the file once only, if it never changed | |
828 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
829 | ||
830 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, | |
831 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 832 | |
44662487 | 833 | DEBUG(D_tls) debug_printf("Set OCSP response file %s\n", &state->exp_tls_ocsp_file); |
2b4a568d JH |
834 | } |
835 | #endif | |
836 | ||
837 | ||
059ec3d9 PH |
838 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
839 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
840 | error message is provided. However, if we just refrain from setting anything up | |
841 | in that case, certificate verification fails, which seems to be the correct | |
842 | behaviour. */ | |
843 | ||
17c76198 | 844 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 845 | { |
17c76198 | 846 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 847 | return DEFER; |
17c76198 PP |
848 | if (state->tls_crl && *state->tls_crl) |
849 | if (!expand_check_tlsvar(tls_crl)) | |
850 | return DEFER; | |
059ec3d9 | 851 | |
1365611d PP |
852 | if (!(state->exp_tls_verify_certificates && |
853 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
854 | { |
855 | DEBUG(D_tls) | |
1365611d PP |
856 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
857 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 858 | return OK; |
b34fc30c | 859 | } |
1365611d | 860 | } |
83e2f8a2 PP |
861 | else |
862 | { | |
863 | DEBUG(D_tls) | |
864 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
865 | return OK; | |
866 | } | |
17c76198 | 867 | |
1365611d PP |
868 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
869 | { | |
870 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
871 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
872 | strerror(errno)); | |
873 | return DEFER; | |
874 | } | |
17c76198 | 875 | |
619b2b25 PP |
876 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
877 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
878 | other weirdness. The thing we really want to check is that it's not a | |
879 | directory, since while OpenSSL supports that, GnuTLS does not. | |
880 | So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ | |
881 | if (S_ISDIR(statbuf.st_mode)) | |
1365611d PP |
882 | { |
883 | DEBUG(D_tls) | |
619b2b25 PP |
884 | debug_printf("verify certificates path is a dir: \"%s\"\n", |
885 | state->exp_tls_verify_certificates); | |
1365611d | 886 | log_write(0, LOG_MAIN|LOG_PANIC, |
619b2b25 | 887 | "tls_verify_certificates \"%s\" is a directory", |
1365611d PP |
888 | state->exp_tls_verify_certificates); |
889 | return DEFER; | |
890 | } | |
059ec3d9 | 891 | |
1365611d PP |
892 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
893 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 894 | |
1365611d PP |
895 | if (statbuf.st_size == 0) |
896 | { | |
897 | DEBUG(D_tls) | |
898 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
899 | return OK; | |
900 | } | |
059ec3d9 | 901 | |
1365611d PP |
902 | cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, |
903 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
904 | if (cert_count < 0) | |
905 | { | |
906 | rc = cert_count; | |
907 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); | |
908 | } | |
909 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 910 | |
5c8cda3a PP |
911 | if (state->tls_crl && *state->tls_crl && |
912 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 913 | { |
5c8cda3a PP |
914 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
915 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
916 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
917 | if (cert_count < 0) | |
1365611d | 918 | { |
5c8cda3a | 919 | rc = cert_count; |
1365611d PP |
920 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
921 | } | |
5c8cda3a | 922 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 923 | } |
059ec3d9 | 924 | |
059ec3d9 PH |
925 | return OK; |
926 | } | |
927 | ||
928 | ||
929 | ||
930 | ||
1365611d PP |
931 | /************************************************* |
932 | * Set X.509 state variables * | |
933 | *************************************************/ | |
934 | ||
935 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
936 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
937 | structure. Which means various other non-re-expanded pieces of state | |
938 | need to be re-set in the new struct, so the setting logic is pulled | |
939 | out to this. | |
940 | ||
941 | Arguments: | |
942 | state exim_gnutls_state_st * | |
943 | ||
944 | Returns: OK/DEFER/FAIL | |
945 | */ | |
946 | ||
947 | static int | |
948 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
949 | { | |
950 | int rc; | |
951 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
952 | ||
953 | /* Create D-H parameters, or read them from the cache file. This function does | |
954 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
955 | client-side params. */ | |
956 | ||
957 | if (!state->host) | |
958 | { | |
959 | if (!dh_server_params) | |
960 | { | |
961 | rc = init_server_dh(); | |
962 | if (rc != OK) return rc; | |
963 | } | |
964 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
965 | } | |
966 | ||
967 | /* Link the credentials to the session. */ | |
968 | ||
969 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
970 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
971 | ||
972 | return OK; | |
973 | } | |
974 | ||
059ec3d9 | 975 | /************************************************* |
17c76198 | 976 | * Initialize for GnuTLS * |
059ec3d9 PH |
977 | *************************************************/ |
978 | ||
17c76198 PP |
979 | /* Called from both server and client code. In the case of a server, errors |
980 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
981 | |
982 | Arguments: | |
17c76198 PP |
983 | host connected host, if client; NULL if server |
984 | certificate certificate file | |
985 | privatekey private key file | |
986 | sni TLS SNI to send, sometimes when client; else NULL | |
987 | cas CA certs file | |
988 | crl CRL file | |
989 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 990 | caller_state returned state-info structure |
059ec3d9 | 991 | |
17c76198 | 992 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
993 | */ |
994 | ||
17c76198 PP |
995 | static int |
996 | tls_init( | |
997 | const host_item *host, | |
998 | const uschar *certificate, | |
999 | const uschar *privatekey, | |
1000 | const uschar *sni, | |
1001 | const uschar *cas, | |
1002 | const uschar *crl, | |
1003 | const uschar *require_ciphers, | |
1004 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 1005 | { |
17c76198 PP |
1006 | exim_gnutls_state_st *state; |
1007 | int rc; | |
1008 | size_t sz; | |
1009 | const char *errpos; | |
1010 | uschar *p; | |
1011 | BOOL want_default_priorities; | |
1012 | ||
1013 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1014 | { |
17c76198 PP |
1015 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1016 | ||
a5f239e4 PP |
1017 | #ifdef HAVE_GNUTLS_PKCS11 |
1018 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1019 | which loads modules from a config file, which sounds good and may be wanted | |
1020 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1021 | environment variables are used and so breaks for users calling mailq. | |
1022 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1023 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1024 | { |
1025 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1026 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1027 | } | |
1028 | #endif | |
1029 | ||
17c76198 PP |
1030 | rc = gnutls_global_init(); |
1031 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1032 | ||
1033 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1034 | DEBUG(D_tls) | |
059ec3d9 | 1035 | { |
17c76198 PP |
1036 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1037 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1038 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1039 | } |
17c76198 PP |
1040 | #endif |
1041 | ||
1042 | exim_gnutls_base_init_done = TRUE; | |
059ec3d9 | 1043 | } |
059ec3d9 | 1044 | |
17c76198 PP |
1045 | if (host) |
1046 | { | |
1047 | state = &state_client; | |
1048 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1049 | state->tlsp = &tls_out; |
17c76198 PP |
1050 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1051 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1052 | } | |
1053 | else | |
1054 | { | |
1055 | state = &state_server; | |
1056 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1057 | state->tlsp = &tls_in; |
17c76198 PP |
1058 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1059 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1060 | } | |
1061 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1062 | |
17c76198 | 1063 | state->host = host; |
059ec3d9 | 1064 | |
17c76198 PP |
1065 | state->tls_certificate = certificate; |
1066 | state->tls_privatekey = privatekey; | |
5779e6aa | 1067 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1068 | state->tls_sni = sni; |
1069 | state->tls_verify_certificates = cas; | |
1070 | state->tls_crl = crl; | |
059ec3d9 | 1071 | |
17c76198 PP |
1072 | /* This handles the variables that might get re-expanded after TLS SNI; |
1073 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1074 | |
17c76198 PP |
1075 | DEBUG(D_tls) |
1076 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
1077 | rc = tls_expand_session_files(state); | |
1078 | if (rc != OK) return rc; | |
059ec3d9 | 1079 | |
1365611d PP |
1080 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1081 | requires a new structure afterwards. */ | |
83da1223 | 1082 | |
1365611d PP |
1083 | rc = tls_set_remaining_x509(state); |
1084 | if (rc != OK) return rc; | |
83da1223 | 1085 | |
17c76198 PP |
1086 | /* set SNI in client, only */ |
1087 | if (host) | |
1088 | { | |
a5f239e4 | 1089 | if (!expand_check(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni)) |
17c76198 PP |
1090 | return DEFER; |
1091 | if (state->exp_tls_sni && *state->exp_tls_sni) | |
1092 | { | |
1093 | DEBUG(D_tls) | |
1094 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); | |
1095 | sz = Ustrlen(state->exp_tls_sni); | |
1096 | rc = gnutls_server_name_set(state->session, | |
1097 | GNUTLS_NAME_DNS, state->exp_tls_sni, sz); | |
1098 | exim_gnutls_err_check(US"gnutls_server_name_set"); | |
1099 | } | |
1100 | } | |
1101 | else if (state->tls_sni) | |
1102 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1103 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1104 | |
17c76198 | 1105 | /* This is the priority string support, |
42bfef1e | 1106 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1107 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1108 | This was backwards incompatible, but means Exim no longer needs to track | |
1109 | all algorithms and provide string forms for them. */ | |
83da1223 | 1110 | |
17c76198 | 1111 | want_default_priorities = TRUE; |
83da1223 | 1112 | |
17c76198 | 1113 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1114 | { |
17c76198 PP |
1115 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1116 | return DEFER; | |
1117 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1118 | { |
17c76198 PP |
1119 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1120 | state->exp_tls_require_ciphers); | |
1121 | ||
1122 | rc = gnutls_priority_init(&state->priority_cache, | |
1123 | CS state->exp_tls_require_ciphers, &errpos); | |
1124 | want_default_priorities = FALSE; | |
1125 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1126 | } |
1127 | } | |
17c76198 PP |
1128 | if (want_default_priorities) |
1129 | { | |
83e2f8a2 PP |
1130 | DEBUG(D_tls) |
1131 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1132 | exim_default_gnutls_priority); | |
17c76198 PP |
1133 | rc = gnutls_priority_init(&state->priority_cache, |
1134 | exim_default_gnutls_priority, &errpos); | |
1135 | p = US exim_default_gnutls_priority; | |
1136 | } | |
83da1223 | 1137 | |
17c76198 PP |
1138 | exim_gnutls_err_check(string_sprintf( |
1139 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1140 | p, errpos - CS p, errpos)); | |
1141 | ||
1142 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1143 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1144 | ||
1145 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1146 | ||
1147 | /* Reduce security in favour of increased compatibility, if the admin | |
1148 | decides to make that trade-off. */ | |
1149 | if (gnutls_compat_mode) | |
83da1223 | 1150 | { |
17c76198 PP |
1151 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1152 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1153 | gnutls_session_enable_compatibility_mode(state->session); | |
1154 | #else | |
1155 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1156 | #endif | |
83da1223 PH |
1157 | } |
1158 | ||
17c76198 | 1159 | *caller_state = state; |
17c76198 | 1160 | return OK; |
83da1223 PH |
1161 | } |
1162 | ||
1163 | ||
1164 | ||
059ec3d9 | 1165 | /************************************************* |
17c76198 | 1166 | * Extract peer information * |
059ec3d9 PH |
1167 | *************************************************/ |
1168 | ||
17c76198 | 1169 | /* Called from both server and client code. |
4fe99a6c PP |
1170 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1171 | and we use that to detect double-calls. | |
059ec3d9 | 1172 | |
75fe387d PP |
1173 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1174 | for logging in the server side, but for the client side, we log after teardown | |
1175 | in src/deliver.c. While the session is up, we can twist about states and | |
1176 | repoint tls_* globals, but those variables used for logging or other variable | |
1177 | expansion that happens _after_ delivery need to have a longer life-time. | |
1178 | ||
1179 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1180 | doing this more than once per generation of a state context. We set them in | |
1181 | the state context, and repoint tls_* to them. After the state goes away, the | |
1182 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1183 | ||
1184 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1185 | don't apply. | |
1186 | ||
059ec3d9 | 1187 | Arguments: |
17c76198 | 1188 | state exim_gnutls_state_st * |
059ec3d9 | 1189 | |
17c76198 | 1190 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1191 | */ |
1192 | ||
17c76198 PP |
1193 | static int |
1194 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1195 | { |
75fe387d | 1196 | uschar cipherbuf[256]; |
17c76198 | 1197 | const gnutls_datum *cert_list; |
75fe387d | 1198 | int old_pool, rc; |
17c76198 | 1199 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1200 | gnutls_protocol_t protocol; |
1201 | gnutls_cipher_algorithm_t cipher; | |
1202 | gnutls_kx_algorithm_t kx; | |
1203 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1204 | gnutls_certificate_type_t ct; |
1205 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1206 | uschar *p, *dn_buf; |
17c76198 | 1207 | size_t sz; |
059ec3d9 | 1208 | |
4fe99a6c | 1209 | if (state->have_set_peerdn) |
17c76198 | 1210 | return OK; |
4fe99a6c | 1211 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1212 | |
4fe99a6c | 1213 | state->peerdn = NULL; |
059ec3d9 | 1214 | |
4fe99a6c PP |
1215 | /* tls_cipher */ |
1216 | cipher = gnutls_cipher_get(state->session); | |
1217 | protocol = gnutls_protocol_get_version(state->session); | |
1218 | mac = gnutls_mac_get(state->session); | |
1219 | kx = gnutls_kx_get(state->session); | |
1220 | ||
75fe387d | 1221 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1222 | "%s:%s:%d", |
1223 | gnutls_protocol_get_name(protocol), | |
1224 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1225 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1226 | ||
1227 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1228 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1229 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1230 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1231 | if (isspace(*p)) |
1232 | *p = '-'; | |
75fe387d PP |
1233 | old_pool = store_pool; |
1234 | store_pool = POOL_PERM; | |
1235 | state->ciphersuite = string_copy(cipherbuf); | |
1236 | store_pool = old_pool; | |
817d9f57 | 1237 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1238 | |
1239 | /* tls_peerdn */ | |
17c76198 | 1240 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1241 | |
17c76198 PP |
1242 | if (cert_list == NULL || cert_list_size == 0) |
1243 | { | |
17c76198 PP |
1244 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1245 | cert_list, cert_list_size); | |
e51c7be2 | 1246 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1247 | return tls_error(US"certificate verification failed", |
1248 | "no certificate received from peer", state->host); | |
1249 | return OK; | |
1250 | } | |
059ec3d9 | 1251 | |
17c76198 PP |
1252 | ct = gnutls_certificate_type_get(state->session); |
1253 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1254 | { |
17c76198 | 1255 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1256 | DEBUG(D_tls) |
1257 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1258 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1259 | return tls_error(US"certificate verification not possible, unhandled type", |
1260 | ctn, state->host); | |
1261 | return OK; | |
83da1223 | 1262 | } |
059ec3d9 | 1263 | |
e51c7be2 JH |
1264 | #define exim_gnutls_peer_err(Label) \ |
1265 | do { \ | |
1266 | if (rc != GNUTLS_E_SUCCESS) \ | |
1267 | { \ | |
1268 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1269 | (Label), gnutls_strerror(rc)); \ | |
1270 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
1271 | return tls_error((Label), gnutls_strerror(rc), state->host); \ | |
1272 | return OK; \ | |
1273 | } \ | |
1274 | } while (0) | |
17c76198 | 1275 | |
9d1c15ef JH |
1276 | rc = import_cert(&cert_list[0], &crt); |
1277 | exim_gnutls_peer_err(US"cert 0"); | |
1278 | ||
1279 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1280 | |
17c76198 PP |
1281 | sz = 0; |
1282 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1283 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1284 | { |
17c76198 PP |
1285 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1286 | return FAIL; /* should not happen */ | |
059ec3d9 | 1287 | } |
17c76198 PP |
1288 | dn_buf = store_get_perm(sz); |
1289 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1290 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1291 | |
17c76198 PP |
1292 | state->peerdn = dn_buf; |
1293 | ||
1294 | return OK; | |
1295 | #undef exim_gnutls_peer_err | |
1296 | } | |
059ec3d9 | 1297 | |
059ec3d9 | 1298 | |
059ec3d9 | 1299 | |
059ec3d9 | 1300 | |
17c76198 PP |
1301 | /************************************************* |
1302 | * Verify peer certificate * | |
1303 | *************************************************/ | |
059ec3d9 | 1304 | |
17c76198 PP |
1305 | /* Called from both server and client code. |
1306 | *Should* be using a callback registered with | |
1307 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1308 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1309 | |
17c76198 PP |
1310 | Arguments: |
1311 | state exim_gnutls_state_st * | |
1312 | error where to put an error message | |
059ec3d9 | 1313 | |
17c76198 PP |
1314 | Returns: |
1315 | FALSE if the session should be rejected | |
1316 | TRUE if the cert is okay or we just don't care | |
1317 | */ | |
059ec3d9 | 1318 | |
17c76198 PP |
1319 | static BOOL |
1320 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1321 | { | |
1322 | int rc; | |
1323 | unsigned int verify; | |
1324 | ||
1325 | *error = NULL; | |
1326 | ||
0a92f87f | 1327 | if ((rc = peer_status(state)) != OK) |
e6060e2c | 1328 | { |
17c76198 | 1329 | verify = GNUTLS_CERT_INVALID; |
0a92f87f | 1330 | *error = "certificate not supplied"; |
17c76198 PP |
1331 | } |
1332 | else | |
17c76198 | 1333 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1334 | |
17c76198 PP |
1335 | /* Handle the result of verification. INVALID seems to be set as well |
1336 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1337 | |
e51c7be2 JH |
1338 | if (rc < 0 || |
1339 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1340 | ) | |
17c76198 PP |
1341 | { |
1342 | state->peer_cert_verified = FALSE; | |
0a92f87f JH |
1343 | if (!*error) |
1344 | *error = verify & GNUTLS_CERT_REVOKED | |
1345 | ? "certificate revoked" : "certificate invalid"; | |
059ec3d9 | 1346 | |
17c76198 | 1347 | DEBUG(D_tls) |
e51c7be2 | 1348 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
4fe99a6c | 1349 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1350 | |
e51c7be2 | 1351 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1352 | { |
e51c7be2 JH |
1353 | gnutls_alert_send(state->session, |
1354 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1355 | return FALSE; |
1356 | } | |
1357 | DEBUG(D_tls) | |
4789da3a | 1358 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1359 | } |
e51c7be2 | 1360 | |
17c76198 PP |
1361 | else |
1362 | { | |
e51c7be2 JH |
1363 | #ifdef EXPERIMENTAL_CERTNAMES |
1364 | if (state->verify_requirement == VERIFY_WITHHOST) | |
1365 | { | |
1366 | int sep = 0; | |
1367 | uschar * list = state->exp_tls_verify_cert_hostnames; | |
1368 | uschar * name; | |
1369 | while (name = string_nextinlist(&list, &sep, NULL, 0)) | |
1370 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) | |
1371 | break; | |
1372 | if (!name) | |
1373 | { | |
1374 | DEBUG(D_tls) | |
1375 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
1376 | gnutls_alert_send(state->session, | |
1377 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1378 | return FALSE; | |
1379 | } | |
1380 | } | |
1381 | #endif | |
17c76198 | 1382 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1383 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1384 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1385 | } |
059ec3d9 | 1386 | |
817d9f57 | 1387 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1388 | |
17c76198 PP |
1389 | return TRUE; |
1390 | } | |
059ec3d9 | 1391 | |
17c76198 PP |
1392 | |
1393 | ||
1394 | ||
1395 | /* ------------------------------------------------------------------------ */ | |
1396 | /* Callbacks */ | |
1397 | ||
1398 | /* Logging function which can be registered with | |
1399 | * gnutls_global_set_log_function() | |
1400 | * gnutls_global_set_log_level() 0..9 | |
1401 | */ | |
af3498d6 | 1402 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1403 | static void |
17c76198 | 1404 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1405 | { |
8c79eebf PP |
1406 | size_t len = strlen(message); |
1407 | if (len < 1) | |
1408 | { | |
1409 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1410 | return; | |
1411 | } | |
1412 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1413 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1414 | } |
af3498d6 | 1415 | #endif |
059ec3d9 | 1416 | |
059ec3d9 | 1417 | |
17c76198 PP |
1418 | /* Called after client hello, should handle SNI work. |
1419 | This will always set tls_sni (state->received_sni) if available, | |
1420 | and may trigger presenting different certificates, | |
1421 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1422 | |
17c76198 PP |
1423 | Should be registered with |
1424 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1425 | |
17c76198 PP |
1426 | "This callback must return 0 on success or a gnutls error code to terminate the |
1427 | handshake.". | |
059ec3d9 | 1428 | |
17c76198 PP |
1429 | For inability to get SNI information, we return 0. |
1430 | We only return non-zero if re-setup failed. | |
817d9f57 | 1431 | Only used for server-side TLS. |
17c76198 | 1432 | */ |
44bbabb5 | 1433 | |
17c76198 PP |
1434 | static int |
1435 | exim_sni_handling_cb(gnutls_session_t session) | |
1436 | { | |
1437 | char sni_name[MAX_HOST_LEN]; | |
1438 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1439 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1440 | unsigned int sni_type; |
1441 | int rc, old_pool; | |
1442 | ||
1443 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1444 | if (rc != GNUTLS_E_SUCCESS) |
1445 | { | |
1446 | DEBUG(D_tls) { | |
1447 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1448 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1449 | else | |
1450 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1451 | gnutls_strerror(rc), rc); | |
1452 | }; | |
1453 | return 0; | |
1454 | } | |
1455 | ||
17c76198 PP |
1456 | if (sni_type != GNUTLS_NAME_DNS) |
1457 | { | |
1458 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1459 | return 0; | |
1460 | } | |
44bbabb5 | 1461 | |
17c76198 PP |
1462 | /* We now have a UTF-8 string in sni_name */ |
1463 | old_pool = store_pool; | |
1464 | store_pool = POOL_PERM; | |
1465 | state->received_sni = string_copyn(US sni_name, data_len); | |
1466 | store_pool = old_pool; | |
1467 | ||
1468 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1469 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1470 | |
1471 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1472 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1473 | ||
1474 | if (!state->trigger_sni_changes) | |
1475 | return 0; | |
1476 | ||
1477 | rc = tls_expand_session_files(state); | |
1478 | if (rc != OK) | |
1479 | { | |
1480 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1481 | been offered. The best we can do now is abort. */ | |
1482 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1483 | } | |
1484 | ||
1365611d PP |
1485 | rc = tls_set_remaining_x509(state); |
1486 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1487 | ||
1488 | return 0; | |
059ec3d9 PH |
1489 | } |
1490 | ||
1491 | ||
1492 | ||
f2de3a33 | 1493 | #ifndef DISABLE_OCSP |
44662487 JH |
1494 | |
1495 | static int | |
1496 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1497 | gnutls_datum_t * ocsp_response) | |
1498 | { | |
1499 | int ret; | |
1500 | ||
44662487 JH |
1501 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1502 | { | |
1503 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
1504 | (char *)ptr); | |
018058b2 | 1505 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1506 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1507 | } | |
1508 | ||
018058b2 | 1509 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1510 | return 0; |
1511 | } | |
1512 | ||
1513 | #endif | |
1514 | ||
1515 | ||
1516 | ||
1517 | ||
17c76198 PP |
1518 | |
1519 | /* ------------------------------------------------------------------------ */ | |
1520 | /* Exported functions */ | |
1521 | ||
1522 | ||
1523 | ||
1524 | ||
059ec3d9 PH |
1525 | /************************************************* |
1526 | * Start a TLS session in a server * | |
1527 | *************************************************/ | |
1528 | ||
1529 | /* This is called when Exim is running as a server, after having received | |
1530 | the STARTTLS command. It must respond to that command, and then negotiate | |
1531 | a TLS session. | |
1532 | ||
1533 | Arguments: | |
83da1223 | 1534 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1535 | |
1536 | Returns: OK on success | |
1537 | DEFER for errors before the start of the negotiation | |
1538 | FAIL for errors during the negotation; the server can't | |
1539 | continue running. | |
1540 | */ | |
1541 | ||
1542 | int | |
17c76198 | 1543 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1544 | { |
1545 | int rc; | |
7199e1ee | 1546 | const char *error; |
17c76198 | 1547 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1548 | |
1549 | /* Check for previous activation */ | |
817d9f57 | 1550 | if (tls_in.active >= 0) |
059ec3d9 | 1551 | { |
17c76198 | 1552 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1553 | smtp_printf("554 Already in TLS\r\n"); |
1554 | return FAIL; | |
1555 | } | |
1556 | ||
1557 | /* Initialize the library. If it fails, it will already have logged the error | |
1558 | and sent an SMTP response. */ | |
1559 | ||
17c76198 | 1560 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1561 | |
17c76198 PP |
1562 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1563 | NULL, tls_verify_certificates, tls_crl, | |
1564 | require_ciphers, &state); | |
059ec3d9 PH |
1565 | if (rc != OK) return rc; |
1566 | ||
059ec3d9 PH |
1567 | /* If this is a host for which certificate verification is mandatory or |
1568 | optional, set up appropriately. */ | |
1569 | ||
059ec3d9 | 1570 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1571 | { |
e51c7be2 JH |
1572 | DEBUG(D_tls) |
1573 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1574 | state->verify_requirement = VERIFY_REQUIRED; |
1575 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1576 | } | |
059ec3d9 | 1577 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1578 | { |
e51c7be2 JH |
1579 | DEBUG(D_tls) |
1580 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1581 | state->verify_requirement = VERIFY_OPTIONAL; |
1582 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1583 | } | |
1584 | else | |
1585 | { | |
e51c7be2 JH |
1586 | DEBUG(D_tls) |
1587 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1588 | state->verify_requirement = VERIFY_NONE; |
1589 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1590 | } | |
059ec3d9 | 1591 | |
17c76198 PP |
1592 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1593 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1594 | |
17c76198 PP |
1595 | gnutls_handshake_set_post_client_hello_function(state->session, |
1596 | exim_sni_handling_cb); | |
059ec3d9 PH |
1597 | |
1598 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1599 | on connection, where outputting anything now upsets the clients and tends to | |
1600 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1601 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1602 | mode, the fflush() happens when smtp_getc() is called. */ | |
1603 | ||
817d9f57 | 1604 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1605 | { |
1606 | smtp_printf("220 TLS go ahead\r\n"); | |
9d1c15ef | 1607 | fflush(smtp_out); |
059ec3d9 PH |
1608 | } |
1609 | ||
1610 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1611 | that the GnuTLS library doesn't. */ | |
1612 | ||
17c76198 | 1613 | gnutls_transport_set_ptr2(state->session, |
44662487 JH |
1614 | (gnutls_transport_ptr)(long) fileno(smtp_in), |
1615 | (gnutls_transport_ptr)(long) fileno(smtp_out)); | |
17c76198 PP |
1616 | state->fd_in = fileno(smtp_in); |
1617 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1618 | |
1619 | sigalrm_seen = FALSE; | |
1620 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 PP |
1621 | do |
1622 | { | |
1623 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1624 | } while ((rc == GNUTLS_E_AGAIN) || |
1625 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1626 | alarm(0); |
1627 | ||
17c76198 | 1628 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1629 | { |
17c76198 PP |
1630 | tls_error(US"gnutls_handshake", |
1631 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
059ec3d9 PH |
1632 | /* It seems that, except in the case of a timeout, we have to close the |
1633 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1634 | until the server times out. */ | |
1635 | ||
1636 | if (!sigalrm_seen) | |
1637 | { | |
f1e894f3 PH |
1638 | (void)fclose(smtp_out); |
1639 | (void)fclose(smtp_in); | |
059ec3d9 PH |
1640 | } |
1641 | ||
1642 | return FAIL; | |
1643 | } | |
1644 | ||
1645 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1646 | ||
17c76198 PP |
1647 | /* Verify after the fact */ |
1648 | ||
9d1c15ef JH |
1649 | if ( state->verify_requirement != VERIFY_NONE |
1650 | && !verify_certificate(state, &error)) | |
059ec3d9 | 1651 | { |
9d1c15ef | 1652 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1653 | { |
9d1c15ef JH |
1654 | tls_error(US"certificate verification failed", error, NULL); |
1655 | return FAIL; | |
17c76198 | 1656 | } |
9d1c15ef JH |
1657 | DEBUG(D_tls) |
1658 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1659 | error); | |
059ec3d9 PH |
1660 | } |
1661 | ||
17c76198 PP |
1662 | /* Figure out peer DN, and if authenticated, etc. */ |
1663 | ||
1664 | rc = peer_status(state); | |
1665 | if (rc != OK) return rc; | |
1666 | ||
1667 | /* Sets various Exim expansion variables; always safe within server */ | |
1668 | ||
9d1c15ef | 1669 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1670 | |
1671 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1672 | and initialize appropriately. */ | |
1673 | ||
17c76198 | 1674 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1675 | |
1676 | receive_getc = tls_getc; | |
1677 | receive_ungetc = tls_ungetc; | |
1678 | receive_feof = tls_feof; | |
1679 | receive_ferror = tls_ferror; | |
58eb016e | 1680 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1681 | |
059ec3d9 PH |
1682 | return OK; |
1683 | } | |
1684 | ||
1685 | ||
1686 | ||
1687 | ||
1688 | /************************************************* | |
1689 | * Start a TLS session in a client * | |
1690 | *************************************************/ | |
1691 | ||
1692 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1693 | ||
1694 | Arguments: | |
1695 | fd the fd of the connection | |
1696 | host connected host (for messages) | |
83da1223 | 1697 | addr the first address (not used) |
65867078 | 1698 | ob smtp transport options |
059ec3d9 PH |
1699 | |
1700 | Returns: OK/DEFER/FAIL (because using common functions), | |
1701 | but for a client, DEFER and FAIL have the same meaning | |
1702 | */ | |
1703 | ||
1704 | int | |
17c76198 | 1705 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1706 | address_item *addr ARG_UNUSED, |
65867078 | 1707 | void *v_ob) |
059ec3d9 | 1708 | { |
65867078 | 1709 | smtp_transport_options_block *ob = v_ob; |
059ec3d9 | 1710 | int rc; |
17c76198 PP |
1711 | const char *error; |
1712 | exim_gnutls_state_st *state = NULL; | |
f2de3a33 | 1713 | #ifndef DISABLE_OCSP |
65867078 | 1714 | BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, |
2b4a568d | 1715 | NULL, host->name, host->address, NULL) == OK; |
44662487 JH |
1716 | BOOL request_ocsp = require_ocsp ? TRUE |
1717 | : verify_check_this_host(&ob->hosts_request_ocsp, | |
1718 | NULL, host->name, host->address, NULL) == OK; | |
2b4a568d | 1719 | #endif |
059ec3d9 | 1720 | |
17c76198 | 1721 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1722 | |
65867078 JH |
1723 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
1724 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
1725 | ob->tls_require_ciphers, &state)) != OK) | |
2b4a568d | 1726 | return rc; |
059ec3d9 | 1727 | |
54c90be1 | 1728 | { |
65867078 JH |
1729 | int dh_min_bits = ob->tls_dh_min_bits; |
1730 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
1731 | { | |
1732 | DEBUG(D_tls) | |
1733 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
1734 | " clamping %d up to %d\n", | |
1735 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1736 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1737 | } | |
54c90be1 | 1738 | |
65867078 JH |
1739 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
1740 | " acceptable bits to %d\n", | |
1741 | dh_min_bits); | |
1742 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
1743 | } | |
83da1223 | 1744 | |
2b4a568d JH |
1745 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
1746 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only | |
1747 | the specified host patterns if one of them is defined */ | |
1748 | ||
1749 | if (( state->exp_tls_verify_certificates | |
65867078 JH |
1750 | && !ob->tls_verify_hosts |
1751 | && !ob->tls_try_verify_hosts | |
2b4a568d JH |
1752 | ) |
1753 | || | |
65867078 | 1754 | verify_check_host(&ob->tls_verify_hosts) == OK |
2b4a568d | 1755 | ) |
17c76198 | 1756 | { |
e51c7be2 JH |
1757 | #ifdef EXPERIMENTAL_CERTNAMES |
1758 | if (ob->tls_verify_cert_hostnames) | |
1759 | { | |
1760 | DEBUG(D_tls) | |
1761 | debug_printf("TLS: server cert incl. hostname verification required.\n"); | |
1762 | state->verify_requirement = VERIFY_WITHHOST; | |
1763 | if (!expand_check(ob->tls_verify_cert_hostnames, | |
1764 | US"tls_verify_cert_hostnames", | |
1765 | &state->exp_tls_verify_cert_hostnames)) | |
1766 | return FAIL; | |
1767 | if (state->exp_tls_verify_cert_hostnames) | |
1768 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1769 | state->exp_tls_verify_cert_hostnames); | |
1770 | } | |
1771 | else | |
1772 | #endif | |
1773 | { | |
1774 | DEBUG(D_tls) | |
1775 | debug_printf("TLS: server certificate verification required.\n"); | |
1776 | state->verify_requirement = VERIFY_REQUIRED; | |
1777 | } | |
52f93eed WB |
1778 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
1779 | } | |
65867078 | 1780 | else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) |
52f93eed | 1781 | { |
e51c7be2 JH |
1782 | DEBUG(D_tls) |
1783 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 1784 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
1785 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
1786 | } | |
1787 | else | |
1788 | { | |
e51c7be2 JH |
1789 | DEBUG(D_tls) |
1790 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
1791 | state->verify_requirement = VERIFY_NONE; |
1792 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 1793 | } |
059ec3d9 | 1794 | |
f2de3a33 JH |
1795 | #ifndef DISABLE_OCSP |
1796 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 1797 | if (request_ocsp) |
9d1c15ef JH |
1798 | { |
1799 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
1800 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
1801 | NULL, 0, NULL)) != OK) | |
9d1c15ef JH |
1802 | return tls_error(US"cert-status-req", |
1803 | gnutls_strerror(rc), state->host); | |
44662487 | 1804 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 1805 | } |
2b4a568d JH |
1806 | #endif |
1807 | ||
44662487 | 1808 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)(long) fd); |
17c76198 PP |
1809 | state->fd_in = fd; |
1810 | state->fd_out = fd; | |
059ec3d9 | 1811 | |
9d1c15ef | 1812 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
1813 | /* There doesn't seem to be a built-in timeout on connection. */ |
1814 | ||
1815 | sigalrm_seen = FALSE; | |
65867078 | 1816 | alarm(ob->command_timeout); |
17c76198 PP |
1817 | do |
1818 | { | |
1819 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1820 | } while ((rc == GNUTLS_E_AGAIN) || |
1821 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1822 | alarm(0); |
1823 | ||
4fe99a6c PP |
1824 | if (rc != GNUTLS_E_SUCCESS) |
1825 | return tls_error(US"gnutls_handshake", | |
1826 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
1827 | ||
17c76198 | 1828 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 1829 | |
17c76198 | 1830 | /* Verify late */ |
059ec3d9 | 1831 | |
17c76198 PP |
1832 | if (state->verify_requirement != VERIFY_NONE && |
1833 | !verify_certificate(state, &error)) | |
1834 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 1835 | |
f2de3a33 | 1836 | #ifndef DISABLE_OCSP |
2b4a568d JH |
1837 | if (require_ocsp) |
1838 | { | |
1839 | DEBUG(D_tls) | |
1840 | { | |
1841 | gnutls_datum_t stapling; | |
1842 | gnutls_ocsp_resp_t resp; | |
1843 | gnutls_datum_t printed; | |
1844 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
1845 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
1846 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
1847 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
1848 | ) | |
1849 | { | |
65867078 | 1850 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
1851 | gnutls_free(printed.data); |
1852 | } | |
1853 | else | |
1854 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); | |
1855 | } | |
1856 | ||
2b4a568d | 1857 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
1858 | { |
1859 | tls_out.ocsp = OCSP_FAILED; | |
2b4a568d | 1860 | return tls_error(US"certificate status check failed", NULL, state->host); |
018058b2 | 1861 | } |
2b4a568d | 1862 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 1863 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
1864 | } |
1865 | #endif | |
1866 | ||
17c76198 | 1867 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 1868 | |
2b4a568d JH |
1869 | if ((rc = peer_status(state)) != OK) |
1870 | return rc; | |
059ec3d9 | 1871 | |
4fe99a6c | 1872 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 1873 | |
9d1c15ef | 1874 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 1875 | |
059ec3d9 PH |
1876 | return OK; |
1877 | } | |
1878 | ||
1879 | ||
1880 | ||
17c76198 | 1881 | |
059ec3d9 | 1882 | /************************************************* |
17c76198 | 1883 | * Close down a TLS session * |
059ec3d9 PH |
1884 | *************************************************/ |
1885 | ||
17c76198 PP |
1886 | /* This is also called from within a delivery subprocess forked from the |
1887 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1888 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 1889 | |
17c76198 PP |
1890 | Arguments: TRUE if gnutls_bye is to be called |
1891 | Returns: nothing | |
059ec3d9 PH |
1892 | */ |
1893 | ||
17c76198 | 1894 | void |
817d9f57 | 1895 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1896 | { |
817d9f57 | 1897 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1898 | |
389ca47a | 1899 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
1900 | |
1901 | if (shutdown) | |
1902 | { | |
1903 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1904 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
1905 | } | |
1906 | ||
1907 | gnutls_deinit(state->session); | |
1908 | ||
389ca47a | 1909 | state->tlsp->active = -1; |
17c76198 PP |
1910 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
1911 | ||
1912 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
1913 | { | |
1914 | gnutls_global_deinit(); | |
1915 | exim_gnutls_base_init_done = FALSE; | |
1916 | } | |
7199e1ee | 1917 | |
059ec3d9 PH |
1918 | } |
1919 | ||
1920 | ||
1921 | ||
17c76198 | 1922 | |
059ec3d9 PH |
1923 | /************************************************* |
1924 | * TLS version of getc * | |
1925 | *************************************************/ | |
1926 | ||
1927 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1928 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 1929 | Only used by the server-side TLS. |
059ec3d9 | 1930 | |
17c76198 PP |
1931 | This feeds DKIM and should be used for all message-body reads. |
1932 | ||
059ec3d9 PH |
1933 | Arguments: none |
1934 | Returns: the next character or EOF | |
1935 | */ | |
1936 | ||
1937 | int | |
1938 | tls_getc(void) | |
1939 | { | |
817d9f57 | 1940 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 1941 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 1942 | { |
17c76198 | 1943 | ssize_t inbytes; |
059ec3d9 | 1944 | |
17c76198 PP |
1945 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
1946 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
1947 | |
1948 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1949 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
1950 | ssl_xfer_buffer_size); |
1951 | alarm(0); | |
1952 | ||
1953 | /* A zero-byte return appears to mean that the TLS session has been | |
1954 | closed down, not that the socket itself has been closed down. Revert to | |
1955 | non-TLS handling. */ | |
1956 | ||
1957 | if (inbytes == 0) | |
1958 | { | |
1959 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1960 | ||
1961 | receive_getc = smtp_getc; | |
1962 | receive_ungetc = smtp_ungetc; | |
1963 | receive_feof = smtp_feof; | |
1964 | receive_ferror = smtp_ferror; | |
58eb016e | 1965 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1966 | |
17c76198 PP |
1967 | gnutls_deinit(state->session); |
1968 | state->session = NULL; | |
817d9f57 JH |
1969 | state->tlsp->active = -1; |
1970 | state->tlsp->bits = 0; | |
1971 | state->tlsp->certificate_verified = FALSE; | |
9d1c15ef | 1972 | tls_channelbinding_b64 = NULL; |
817d9f57 | 1973 | state->tlsp->cipher = NULL; |
9d1c15ef | 1974 | state->tlsp->peercert = NULL; |
817d9f57 | 1975 | state->tlsp->peerdn = NULL; |
059ec3d9 PH |
1976 | |
1977 | return smtp_getc(); | |
1978 | } | |
1979 | ||
1980 | /* Handle genuine errors */ | |
1981 | ||
1982 | else if (inbytes < 0) | |
1983 | { | |
17c76198 PP |
1984 | record_io_error(state, (int) inbytes, US"recv", NULL); |
1985 | state->xfer_error = 1; | |
059ec3d9 PH |
1986 | return EOF; |
1987 | } | |
80a47a2c | 1988 | #ifndef DISABLE_DKIM |
17c76198 | 1989 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 1990 | #endif |
17c76198 PP |
1991 | state->xfer_buffer_hwm = (int) inbytes; |
1992 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
1993 | } |
1994 | ||
059ec3d9 PH |
1995 | /* Something in the buffer; return next uschar */ |
1996 | ||
17c76198 | 1997 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
1998 | } |
1999 | ||
2000 | ||
2001 | ||
17c76198 | 2002 | |
059ec3d9 PH |
2003 | /************************************************* |
2004 | * Read bytes from TLS channel * | |
2005 | *************************************************/ | |
2006 | ||
17c76198 PP |
2007 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2008 | then the caller must feed DKIM. | |
817d9f57 | 2009 | |
059ec3d9 PH |
2010 | Arguments: |
2011 | buff buffer of data | |
2012 | len size of buffer | |
2013 | ||
2014 | Returns: the number of bytes read | |
2015 | -1 after a failed read | |
2016 | */ | |
2017 | ||
2018 | int | |
817d9f57 | 2019 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2020 | { |
817d9f57 | 2021 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2022 | ssize_t inbytes; |
059ec3d9 | 2023 | |
17c76198 PP |
2024 | if (len > INT_MAX) |
2025 | len = INT_MAX; | |
059ec3d9 | 2026 | |
17c76198 PP |
2027 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2028 | DEBUG(D_tls) | |
2029 | debug_printf("*** PROBABLY A BUG *** " \ | |
2030 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2031 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2032 | ||
2033 | DEBUG(D_tls) | |
2034 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2035 | state->session, buff, len); | |
2036 | ||
2037 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2038 | if (inbytes > 0) return inbytes; |
2039 | if (inbytes == 0) | |
2040 | { | |
2041 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2042 | } | |
17c76198 | 2043 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2044 | |
2045 | return -1; | |
2046 | } | |
2047 | ||
2048 | ||
2049 | ||
17c76198 | 2050 | |
059ec3d9 PH |
2051 | /************************************************* |
2052 | * Write bytes down TLS channel * | |
2053 | *************************************************/ | |
2054 | ||
2055 | /* | |
2056 | Arguments: | |
817d9f57 | 2057 | is_server channel specifier |
059ec3d9 PH |
2058 | buff buffer of data |
2059 | len number of bytes | |
2060 | ||
2061 | Returns: the number of bytes after a successful write, | |
2062 | -1 after a failed write | |
2063 | */ | |
2064 | ||
2065 | int | |
817d9f57 | 2066 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 2067 | { |
17c76198 PP |
2068 | ssize_t outbytes; |
2069 | size_t left = len; | |
817d9f57 | 2070 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2071 | |
17c76198 | 2072 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
2073 | while (left > 0) |
2074 | { | |
17c76198 PP |
2075 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2076 | buff, left); | |
2077 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2078 | |
17c76198 | 2079 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2080 | if (outbytes < 0) |
2081 | { | |
17c76198 | 2082 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2083 | return -1; |
2084 | } | |
2085 | if (outbytes == 0) | |
2086 | { | |
17c76198 | 2087 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2088 | return -1; |
2089 | } | |
2090 | ||
2091 | left -= outbytes; | |
2092 | buff += outbytes; | |
2093 | } | |
2094 | ||
17c76198 PP |
2095 | if (len > INT_MAX) |
2096 | { | |
2097 | DEBUG(D_tls) | |
2098 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2099 | len); | |
2100 | len = INT_MAX; | |
2101 | } | |
2102 | ||
2103 | return (int) len; | |
059ec3d9 PH |
2104 | } |
2105 | ||
2106 | ||
2107 | ||
17c76198 | 2108 | |
059ec3d9 | 2109 | /************************************************* |
17c76198 | 2110 | * Random number generation * |
059ec3d9 PH |
2111 | *************************************************/ |
2112 | ||
17c76198 PP |
2113 | /* Pseudo-random number generation. The result is not expected to be |
2114 | cryptographically strong but not so weak that someone will shoot themselves | |
2115 | in the foot using it as a nonce in input in some email header scheme or | |
2116 | whatever weirdness they'll twist this into. The result should handle fork() | |
2117 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2118 | |
17c76198 PP |
2119 | Arguments: |
2120 | max range maximum | |
2121 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2122 | */ |
2123 | ||
af3498d6 | 2124 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2125 | int |
2126 | vaguely_random_number(int max) | |
059ec3d9 | 2127 | { |
17c76198 PP |
2128 | unsigned int r; |
2129 | int i, needed_len; | |
2130 | uschar *p; | |
2131 | uschar smallbuf[sizeof(r)]; | |
2132 | ||
2133 | if (max <= 1) | |
2134 | return 0; | |
2135 | ||
2136 | needed_len = sizeof(r); | |
2137 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2138 | * asked for a number less than 10. */ | |
2139 | for (r = max, i = 0; r; ++i) | |
2140 | r >>= 1; | |
2141 | i = (i + 7) / 8; | |
2142 | if (i < needed_len) | |
2143 | needed_len = i; | |
2144 | ||
2145 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2146 | if (i < 0) | |
059ec3d9 | 2147 | { |
17c76198 PP |
2148 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2149 | return vaguely_random_number_fallback(max); | |
2150 | } | |
2151 | r = 0; | |
2152 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2153 | { | |
2154 | r *= 256; | |
2155 | r += *p; | |
059ec3d9 PH |
2156 | } |
2157 | ||
17c76198 PP |
2158 | /* We don't particularly care about weighted results; if someone wants |
2159 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2160 | return r % max; | |
059ec3d9 | 2161 | } |
af3498d6 PP |
2162 | #else /* HAVE_GNUTLS_RND */ |
2163 | int | |
2164 | vaguely_random_number(int max) | |
2165 | { | |
2166 | return vaguely_random_number_fallback(max); | |
2167 | } | |
2168 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2169 | |
36f12725 NM |
2170 | |
2171 | ||
2172 | ||
3375e053 PP |
2173 | /************************************************* |
2174 | * Let tls_require_ciphers be checked at startup * | |
2175 | *************************************************/ | |
2176 | ||
2177 | /* The tls_require_ciphers option, if set, must be something which the | |
2178 | library can parse. | |
2179 | ||
2180 | Returns: NULL on success, or error message | |
2181 | */ | |
2182 | ||
2183 | uschar * | |
2184 | tls_validate_require_cipher(void) | |
2185 | { | |
2186 | int rc; | |
2187 | uschar *expciphers = NULL; | |
2188 | gnutls_priority_t priority_cache; | |
2189 | const char *errpos; | |
2190 | ||
2191 | #define validate_check_rc(Label) do { \ | |
2192 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2193 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2194 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2195 | ||
2196 | if (exim_gnutls_base_init_done) | |
2197 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2198 | "already initialised GnuTLS, Exim developer bug"); | |
2199 | ||
a5f239e4 | 2200 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2201 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2202 | { |
2203 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2204 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2205 | } | |
2206 | #endif | |
3375e053 PP |
2207 | rc = gnutls_global_init(); |
2208 | validate_check_rc(US"gnutls_global_init()"); | |
2209 | exim_gnutls_base_init_done = TRUE; | |
2210 | ||
2211 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2212 | return_deinit(NULL); | |
2213 | ||
2214 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2215 | return_deinit(US"failed to expand tls_require_ciphers"); | |
2216 | ||
2217 | if (!(expciphers && *expciphers)) | |
2218 | return_deinit(NULL); | |
2219 | ||
2220 | DEBUG(D_tls) | |
2221 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2222 | ||
2223 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2224 | validate_check_rc(string_sprintf( | |
2225 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2226 | expciphers, errpos - CS expciphers, errpos)); | |
2227 | ||
2228 | #undef return_deinit | |
2229 | #undef validate_check_rc | |
2230 | gnutls_global_deinit(); | |
2231 | ||
2232 | return NULL; | |
2233 | } | |
2234 | ||
2235 | ||
2236 | ||
2237 | ||
36f12725 NM |
2238 | /************************************************* |
2239 | * Report the library versions. * | |
2240 | *************************************************/ | |
2241 | ||
2242 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2243 | ||
2244 | Arguments: a FILE* to print the results to | |
2245 | Returns: nothing | |
2246 | */ | |
2247 | ||
2248 | void | |
2249 | tls_version_report(FILE *f) | |
2250 | { | |
754a0503 PP |
2251 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2252 | " Runtime: %s\n", | |
2253 | LIBGNUTLS_VERSION, | |
2254 | gnutls_check_version(NULL)); | |
36f12725 NM |
2255 | } |
2256 | ||
2b4a568d JH |
2257 | /* vi: aw ai sw=2 |
2258 | */ | |
059ec3d9 | 2259 | /* End of tls-gnu.c */ |