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 | |
a7538db1 JH |
50 | #if GNUTLS_VERSION_NUMBER < 0x020a00 && defined(EXPERIMENTAL_TPDA) |
51 | # warning "GnuTLS library version too old; TPDA tls:cert event unsupported" | |
52 | # undef EXPERIMENTAL_TPDA | |
53 | #endif | |
a7fec7a7 JH |
54 | #if GNUTLS_VERSION_NUMBER >= 0x030306 |
55 | # define SUPPORT_CA_DIR | |
56 | #else | |
57 | # undef SUPPORT_CA_DIR | |
58 | #endif | |
7e07527a | 59 | |
f2de3a33 | 60 | #ifndef DISABLE_OCSP |
2b4a568d JH |
61 | # include <gnutls/ocsp.h> |
62 | #endif | |
059ec3d9 | 63 | |
17c76198 | 64 | /* GnuTLS 2 vs 3 |
059ec3d9 | 65 | |
17c76198 PP |
66 | GnuTLS 3 only: |
67 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 68 | |
17c76198 PP |
69 | Changes: |
70 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
71 | */ | |
059ec3d9 | 72 | |
17c76198 | 73 | /* Local static variables for GnuTLS */ |
059ec3d9 | 74 | |
17c76198 | 75 | /* Values for verify_requirement */ |
059ec3d9 | 76 | |
e51c7be2 JH |
77 | enum peer_verify_requirement |
78 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED | |
79 | #ifdef EXPERIMENTAL_CERTNAMES | |
80 | ,VERIFY_WITHHOST | |
81 | #endif | |
82 | }; | |
059ec3d9 | 83 | |
17c76198 PP |
84 | /* This holds most state for server or client; with this, we can set up an |
85 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
86 | over the TLS variables available for expansion. | |
059ec3d9 | 87 | |
17c76198 PP |
88 | Some of these correspond to variables in globals.c; those variables will |
89 | be set to point to content in one of these instances, as appropriate for | |
90 | the stage of the process lifetime. | |
059ec3d9 | 91 | |
389ca47a | 92 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 93 | */ |
059ec3d9 | 94 | |
17c76198 | 95 | typedef struct exim_gnutls_state { |
9d1c15ef | 96 | gnutls_session_t session; |
17c76198 | 97 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 98 | gnutls_priority_t priority_cache; |
17c76198 | 99 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
100 | int fd_in; |
101 | int fd_out; | |
102 | BOOL peer_cert_verified; | |
103 | BOOL trigger_sni_changes; | |
104 | BOOL have_set_peerdn; | |
17c76198 | 105 | const struct host_item *host; |
9d1c15ef JH |
106 | gnutls_x509_crt_t peercert; |
107 | uschar *peerdn; | |
108 | uschar *ciphersuite; | |
109 | uschar *received_sni; | |
17c76198 PP |
110 | |
111 | const uschar *tls_certificate; | |
112 | const uschar *tls_privatekey; | |
113 | const uschar *tls_sni; /* client send only, not received */ | |
114 | const uschar *tls_verify_certificates; | |
115 | const uschar *tls_crl; | |
116 | const uschar *tls_require_ciphers; | |
e51c7be2 | 117 | |
17c76198 PP |
118 | uschar *exp_tls_certificate; |
119 | uschar *exp_tls_privatekey; | |
17c76198 PP |
120 | uschar *exp_tls_verify_certificates; |
121 | uschar *exp_tls_crl; | |
122 | uschar *exp_tls_require_ciphers; | |
44662487 | 123 | uschar *exp_tls_ocsp_file; |
e51c7be2 JH |
124 | #ifdef EXPERIMENTAL_CERTNAMES |
125 | uschar *exp_tls_verify_cert_hostnames; | |
126 | #endif | |
a7538db1 JH |
127 | #ifdef EXPERIMENTAL_TPDA |
128 | uschar *event_action; | |
129 | #endif | |
17c76198 | 130 | |
389ca47a | 131 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 132 | |
17c76198 PP |
133 | uschar *xfer_buffer; |
134 | int xfer_buffer_lwm; | |
135 | int xfer_buffer_hwm; | |
136 | int xfer_eof; | |
137 | int xfer_error; | |
17c76198 PP |
138 | } exim_gnutls_state_st; |
139 | ||
140 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 141 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 142 | NULL, NULL, NULL, NULL, |
17c76198 | 143 | NULL, NULL, NULL, NULL, NULL, NULL, |
44662487 | 144 | NULL, NULL, NULL, NULL, NULL, NULL, NULL, |
e51c7be2 JH |
145 | #ifdef EXPERIMENTAL_CERTNAMES |
146 | NULL, | |
a7538db1 JH |
147 | #endif |
148 | #ifdef EXPERIMENTAL_TPDA | |
149 | NULL, | |
e51c7be2 | 150 | #endif |
817d9f57 | 151 | NULL, |
17c76198 | 152 | NULL, 0, 0, 0, 0, |
17c76198 | 153 | }; |
83da1223 | 154 | |
17c76198 PP |
155 | /* Not only do we have our own APIs which don't pass around state, assuming |
156 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
157 | for callbacks, or as part of the session, so we have to keep a "this is the | |
158 | context we're currently dealing with" pointer and rely upon being | |
159 | single-threaded to keep from processing data on an inbound TLS connection while | |
160 | talking to another TLS connection for an outbound check. This does mean that | |
161 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
162 | second connection. |
163 | XXX But see gnutls_session_get_ptr() | |
164 | */ | |
059ec3d9 | 165 | |
17c76198 | 166 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 167 | |
17c76198 PP |
168 | /* dh_params are initialised once within the lifetime of a process using TLS; |
169 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
170 | don't want to repeat this. */ | |
83da1223 | 171 | |
17c76198 | 172 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 173 | |
17c76198 | 174 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 175 | |
17c76198 | 176 | static const int ssl_session_timeout = 200; |
059ec3d9 | 177 | |
17c76198 | 178 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 179 | |
17c76198 | 180 | /* Guard library core initialisation */ |
83da1223 | 181 | |
17c76198 | 182 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 183 | |
059ec3d9 | 184 | |
17c76198 PP |
185 | /* ------------------------------------------------------------------------ */ |
186 | /* macros */ | |
83da1223 | 187 | |
17c76198 | 188 | #define MAX_HOST_LEN 255 |
83da1223 | 189 | |
17c76198 PP |
190 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
191 | the library logging; a value less than 0 disables the calls to set up logging | |
192 | callbacks. */ | |
2c17bb02 | 193 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 194 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 195 | #endif |
83da1223 | 196 | |
2c17bb02 | 197 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 198 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 199 | #endif |
83da1223 | 200 | |
af3498d6 PP |
201 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
202 | can ask for a bit-strength. Without that, we stick to the constant we had | |
203 | before, for now. */ | |
2c17bb02 | 204 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 205 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 206 | #endif |
af3498d6 | 207 | |
17c76198 PP |
208 | #define exim_gnutls_err_check(Label) do { \ |
209 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 210 | |
17c76198 | 211 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 212 | |
17c76198 | 213 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
214 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
215 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
216 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
217 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
218 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
219 | * isn't available sometimes, so this needs to become a conditional | |
220 | * compilation; the sanest way to deal with this being a problem on | |
221 | * older OSes is to block it in the Local/Makefile with this compiler | |
222 | * definition */ | |
e51c7be2 JH |
223 | # ifndef AVOID_GNUTLS_PKCS11 |
224 | # define HAVE_GNUTLS_PKCS11 | |
225 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 226 | #endif |
83da1223 | 227 | |
af3498d6 PP |
228 | |
229 | ||
230 | ||
231 | /* ------------------------------------------------------------------------ */ | |
232 | /* Callback declarations */ | |
233 | ||
234 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
235 | static void exim_gnutls_logger_cb(int level, const char *message); | |
236 | #endif | |
237 | ||
238 | static int exim_sni_handling_cb(gnutls_session_t session); | |
239 | ||
f2de3a33 | 240 | #ifndef DISABLE_OCSP |
44662487 JH |
241 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
242 | gnutls_datum_t * ocsp_response); | |
243 | #endif | |
af3498d6 PP |
244 | |
245 | ||
246 | ||
17c76198 PP |
247 | /* ------------------------------------------------------------------------ */ |
248 | /* Static functions */ | |
059ec3d9 PH |
249 | |
250 | /************************************************* | |
251 | * Handle TLS error * | |
252 | *************************************************/ | |
253 | ||
254 | /* Called from lots of places when errors occur before actually starting to do | |
255 | the TLS handshake, that is, while the session is still in clear. Always returns | |
256 | DEFER for a server and FAIL for a client so that most calls can use "return | |
257 | tls_error(...)" to do this processing and then give an appropriate return. A | |
258 | single function is used for both server and client, because it is called from | |
259 | some shared functions. | |
260 | ||
261 | Argument: | |
262 | prefix text to include in the logged error | |
7199e1ee TF |
263 | msg additional error string (may be NULL) |
264 | usually obtained from gnutls_strerror() | |
17c76198 PP |
265 | host NULL if setting up a server; |
266 | the connected host if setting up a client | |
059ec3d9 PH |
267 | |
268 | Returns: OK/DEFER/FAIL | |
269 | */ | |
270 | ||
271 | static int | |
17c76198 | 272 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 273 | { |
17c76198 PP |
274 | if (host) |
275 | { | |
c562fd30 | 276 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s)%s%s", |
17c76198 PP |
277 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); |
278 | return FAIL; | |
279 | } | |
280 | else | |
059ec3d9 | 281 | { |
7199e1ee | 282 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 283 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee | 284 | conn_info += 5; |
c562fd30 | 285 | /* I'd like to get separated H= here, but too hard for now */ |
7199e1ee | 286 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", |
17c76198 | 287 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
288 | return DEFER; |
289 | } | |
059ec3d9 PH |
290 | } |
291 | ||
292 | ||
293 | ||
17c76198 | 294 | |
059ec3d9 | 295 | /************************************************* |
17c76198 | 296 | * Deal with logging errors during I/O * |
059ec3d9 PH |
297 | *************************************************/ |
298 | ||
17c76198 | 299 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 300 | |
17c76198 PP |
301 | Argument: |
302 | state the current GnuTLS exim state container | |
303 | rc the GnuTLS error code, or 0 if it's a local error | |
304 | when text identifying read or write | |
305 | text local error text when ec is 0 | |
059ec3d9 | 306 | |
17c76198 | 307 | Returns: nothing |
059ec3d9 PH |
308 | */ |
309 | ||
17c76198 PP |
310 | static void |
311 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 312 | { |
17c76198 | 313 | const char *msg; |
059ec3d9 | 314 | |
17c76198 PP |
315 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
316 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
317 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
318 | else | |
319 | msg = gnutls_strerror(rc); | |
059ec3d9 | 320 | |
17c76198 PP |
321 | tls_error(when, msg, state->host); |
322 | } | |
059ec3d9 | 323 | |
059ec3d9 | 324 | |
059ec3d9 | 325 | |
059ec3d9 | 326 | |
17c76198 PP |
327 | /************************************************* |
328 | * Set various Exim expansion vars * | |
329 | *************************************************/ | |
059ec3d9 | 330 | |
e51c7be2 JH |
331 | #define exim_gnutls_cert_err(Label) \ |
332 | do \ | |
333 | { \ | |
334 | if (rc != GNUTLS_E_SUCCESS) \ | |
335 | { \ | |
336 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
337 | (Label), gnutls_strerror(rc)); \ | |
338 | return rc; \ | |
339 | } \ | |
340 | } while (0) | |
9d1c15ef JH |
341 | |
342 | static int | |
343 | import_cert(const gnutls_datum * cert, gnutls_x509_crt_t * crtp) | |
344 | { | |
345 | int rc; | |
346 | ||
347 | rc = gnutls_x509_crt_init(crtp); | |
348 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
349 | ||
350 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
351 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
352 | ||
353 | return rc; | |
354 | } | |
355 | ||
356 | #undef exim_gnutls_cert_err | |
357 | ||
358 | ||
17c76198 PP |
359 | /* We set various Exim global variables from the state, once a session has |
360 | been established. With TLS callouts, may need to change this to stack | |
361 | variables, or just re-call it with the server state after client callout | |
362 | has finished. | |
059ec3d9 | 363 | |
9d1c15ef | 364 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
365 | |
366 | Sets: | |
367 | tls_active fd | |
368 | tls_bits strength indicator | |
369 | tls_certificate_verified bool indicator | |
370 | tls_channelbinding_b64 for some SASL mechanisms | |
371 | tls_cipher a string | |
9d1c15ef | 372 | tls_peercert pointer to library internal |
17c76198 PP |
373 | tls_peerdn a string |
374 | tls_sni a (UTF-8) string | |
9d1c15ef | 375 | tls_ourcert pointer to library internal |
17c76198 PP |
376 | |
377 | Argument: | |
378 | state the relevant exim_gnutls_state_st * | |
379 | */ | |
380 | ||
381 | static void | |
9d1c15ef | 382 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 383 | { |
17c76198 | 384 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
385 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
386 | int old_pool; | |
387 | int rc; | |
388 | gnutls_datum_t channel; | |
389 | #endif | |
9d1c15ef | 390 | tls_support * tlsp = state->tlsp; |
17c76198 | 391 | |
9d1c15ef | 392 | tlsp->active = state->fd_out; |
17c76198 PP |
393 | |
394 | cipher = gnutls_cipher_get(state->session); | |
395 | /* returns size in "bytes" */ | |
9d1c15ef | 396 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 397 | |
9d1c15ef | 398 | tlsp->cipher = state->ciphersuite; |
17c76198 | 399 | |
817d9f57 | 400 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 401 | |
9d1c15ef | 402 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 403 | |
17c76198 PP |
404 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
405 | only available for use for authenticators while this TLS session is running. */ | |
406 | ||
407 | tls_channelbinding_b64 = NULL; | |
408 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
409 | channel.data = NULL; | |
410 | channel.size = 0; | |
411 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
412 | if (rc) { | |
413 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
414 | } else { | |
415 | old_pool = store_pool; | |
416 | store_pool = POOL_PERM; | |
417 | tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); | |
418 | store_pool = old_pool; | |
419 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
420 | } | |
421 | #endif | |
422 | ||
9d1c15ef JH |
423 | /* peercert is set in peer_status() */ |
424 | tlsp->peerdn = state->peerdn; | |
425 | tlsp->sni = state->received_sni; | |
426 | ||
427 | /* record our certificate */ | |
428 | { | |
429 | const gnutls_datum * cert = gnutls_certificate_get_ours(state->session); | |
430 | gnutls_x509_crt_t crt; | |
431 | ||
432 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
433 | } | |
059ec3d9 PH |
434 | } |
435 | ||
436 | ||
437 | ||
17c76198 | 438 | |
059ec3d9 | 439 | /************************************************* |
575643cd | 440 | * Setup up DH parameters * |
059ec3d9 PH |
441 | *************************************************/ |
442 | ||
575643cd | 443 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
444 | be re-generated every so often, depending on security policy. What we do is to |
445 | keep these parameters in a file in the spool directory. If the file does not | |
446 | exist, we generate them. This means that it is easy to cause a regeneration. | |
447 | ||
448 | The new file is written as a temporary file and renamed, so that an incomplete | |
449 | file is never present. If two processes both compute some new parameters, you | |
450 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
451 | prevent this. | |
452 | ||
059ec3d9 PH |
453 | Returns: OK/DEFER/FAIL |
454 | */ | |
455 | ||
456 | static int | |
17c76198 | 457 | init_server_dh(void) |
059ec3d9 | 458 | { |
17c76198 PP |
459 | int fd, rc; |
460 | unsigned int dh_bits; | |
b5aea5e1 | 461 | gnutls_datum m; |
a799883d PP |
462 | uschar filename_buf[PATH_MAX]; |
463 | uschar *filename = NULL; | |
17c76198 | 464 | size_t sz; |
a799883d PP |
465 | uschar *exp_tls_dhparam; |
466 | BOOL use_file_in_spool = FALSE; | |
467 | BOOL use_fixed_file = FALSE; | |
17c76198 | 468 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 469 | |
17c76198 | 470 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 471 | |
17c76198 PP |
472 | rc = gnutls_dh_params_init(&dh_server_params); |
473 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 474 | |
a799883d PP |
475 | m.data = NULL; |
476 | m.size = 0; | |
477 | ||
478 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
479 | return DEFER; | |
480 | ||
481 | if (!exp_tls_dhparam) | |
482 | { | |
483 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
484 | m.data = US std_dh_prime_default(); | |
485 | m.size = Ustrlen(m.data); | |
486 | } | |
487 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
488 | use_file_in_spool = TRUE; | |
489 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
490 | { | |
491 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
492 | return OK; | |
493 | } | |
494 | else if (exp_tls_dhparam[0] != '/') | |
495 | { | |
496 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
497 | if (m.data == NULL) | |
498 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
499 | m.size = Ustrlen(m.data); | |
500 | } | |
501 | else | |
502 | { | |
503 | use_fixed_file = TRUE; | |
504 | filename = exp_tls_dhparam; | |
505 | } | |
506 | ||
507 | if (m.data) | |
508 | { | |
509 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
510 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
511 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
512 | return OK; | |
513 | } | |
514 | ||
af3498d6 PP |
515 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
516 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
517 | different filename and ensure we have sufficient bits. */ |
518 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
519 | if (!dh_bits) | |
520 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 521 | DEBUG(D_tls) |
b34fc30c | 522 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
523 | dh_bits); |
524 | #else | |
525 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
526 | DEBUG(D_tls) | |
527 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
528 | dh_bits); | |
529 | #endif | |
059ec3d9 | 530 | |
3375e053 PP |
531 | /* Some clients have hard-coded limits. */ |
532 | if (dh_bits > tls_dh_max_bits) | |
533 | { | |
534 | DEBUG(D_tls) | |
535 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
536 | tls_dh_max_bits); | |
537 | dh_bits = tls_dh_max_bits; | |
538 | } | |
539 | ||
a799883d PP |
540 | if (use_file_in_spool) |
541 | { | |
542 | if (!string_format(filename_buf, sizeof(filename_buf), | |
543 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
544 | return tls_error(US"overlong filename", NULL, NULL); | |
545 | filename = filename_buf; | |
546 | } | |
059ec3d9 | 547 | |
b5aea5e1 | 548 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 549 | parameters. */ |
059ec3d9 PH |
550 | |
551 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 552 | if (fd >= 0) |
059ec3d9 | 553 | { |
b5aea5e1 | 554 | struct stat statbuf; |
17c76198 PP |
555 | FILE *fp; |
556 | int saved_errno; | |
557 | ||
558 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
559 | { | |
560 | saved_errno = errno; | |
561 | (void)close(fd); | |
562 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
563 | } | |
564 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
565 | { |
566 | (void)close(fd); | |
17c76198 PP |
567 | return tls_error(US"TLS cache not a file", NULL, NULL); |
568 | } | |
569 | fp = fdopen(fd, "rb"); | |
570 | if (!fp) | |
571 | { | |
572 | saved_errno = errno; | |
573 | (void)close(fd); | |
574 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
575 | strerror(saved_errno), NULL); | |
b5aea5e1 | 576 | } |
059ec3d9 | 577 | |
b5aea5e1 PH |
578 | m.size = statbuf.st_size; |
579 | m.data = malloc(m.size); | |
580 | if (m.data == NULL) | |
17c76198 PP |
581 | { |
582 | fclose(fp); | |
583 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
584 | } | |
585 | sz = fread(m.data, m.size, 1, fp); | |
586 | if (!sz) | |
587 | { | |
588 | saved_errno = errno; | |
589 | fclose(fp); | |
590 | free(m.data); | |
591 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
592 | } | |
593 | fclose(fp); | |
b5aea5e1 | 594 | |
17c76198 | 595 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 596 | free(m.data); |
17c76198 PP |
597 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
598 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
599 | } |
600 | ||
601 | /* If the file does not exist, fall through to compute new data and cache it. | |
602 | If there was any other opening error, it is serious. */ | |
603 | ||
182ad5cf PH |
604 | else if (errno == ENOENT) |
605 | { | |
17c76198 | 606 | rc = -1; |
182ad5cf | 607 | DEBUG(D_tls) |
17c76198 | 608 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
609 | } |
610 | else | |
17c76198 PP |
611 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
612 | NULL, NULL); | |
b5aea5e1 PH |
613 | |
614 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
615 | is not useful. One particular case of this is when upgrading from an older | |
616 | release of Exim in which the data was stored in a different format. We don't | |
617 | try to be clever and support both formats; we just regenerate new data in this | |
618 | case. */ | |
619 | ||
17c76198 | 620 | if (rc < 0) |
b5aea5e1 | 621 | { |
17c76198 | 622 | uschar *temp_fn; |
201f5254 | 623 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 624 | |
17c76198 PP |
625 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
626 | return tls_error(US"Filename too long to generate replacement", | |
627 | CS filename, NULL); | |
059ec3d9 | 628 | |
17c76198 PP |
629 | temp_fn = string_copy(US "%s.XXXXXXX"); |
630 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 631 | if (fd < 0) |
17c76198 | 632 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
633 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
634 | ||
201f5254 PP |
635 | /* GnuTLS overshoots! |
636 | * If we ask for 2236, we might get 2237 or more. | |
637 | * But there's no way to ask GnuTLS how many bits there really are. | |
638 | * We can ask how many bits were used in a TLS session, but that's it! | |
639 | * The prime itself is hidden behind too much abstraction. | |
640 | * So we ask for less, and proceed on a wing and a prayer. | |
641 | * First attempt, subtracted 3 for 2233 and got 2240. | |
642 | */ | |
cae6e576 | 643 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
644 | { |
645 | dh_bits_gen = dh_bits - 10; | |
646 | DEBUG(D_tls) | |
647 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
648 | dh_bits_gen); | |
649 | } | |
650 | ||
651 | DEBUG(D_tls) | |
652 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
653 | dh_bits_gen); | |
654 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
655 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
656 | ||
657 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
658 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
659 | sample apps handle this. */ | |
660 | ||
661 | sz = 0; | |
662 | m.data = NULL; | |
663 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
664 | m.data, &sz); | |
665 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
666 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
667 | m.size = sz; | |
b5aea5e1 PH |
668 | m.data = malloc(m.size); |
669 | if (m.data == NULL) | |
17c76198 | 670 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
1f00591e | 671 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 672 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 673 | m.data, &sz); |
17c76198 PP |
674 | if (rc != GNUTLS_E_SUCCESS) |
675 | { | |
676 | free(m.data); | |
677 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
678 | } | |
1f00591e | 679 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 680 | |
17c76198 PP |
681 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
682 | if (sz != m.size) | |
683 | { | |
684 | free(m.data); | |
685 | return tls_error(US"TLS cache write D-H params failed", | |
686 | strerror(errno), NULL); | |
687 | } | |
b5aea5e1 | 688 | free(m.data); |
17c76198 PP |
689 | sz = write_to_fd_buf(fd, US"\n", 1); |
690 | if (sz != 1) | |
691 | return tls_error(US"TLS cache write D-H params final newline failed", | |
692 | strerror(errno), NULL); | |
693 | ||
694 | rc = close(fd); | |
695 | if (rc) | |
696 | return tls_error(US"TLS cache write close() failed", | |
697 | strerror(errno), NULL); | |
059ec3d9 | 698 | |
17c76198 PP |
699 | if (Urename(temp_fn, filename) < 0) |
700 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
701 | temp_fn, filename), strerror(errno), NULL); | |
059ec3d9 | 702 | |
17c76198 | 703 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
704 | } |
705 | ||
17c76198 | 706 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
707 | return OK; |
708 | } | |
709 | ||
710 | ||
711 | ||
712 | ||
713 | /************************************************* | |
17c76198 | 714 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
715 | *************************************************/ |
716 | ||
17c76198 PP |
717 | /* Called from both server and client code, via tls_init(), and also from |
718 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
719 | ||
720 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
721 | ||
722 | The callback should not call us unless state->trigger_sni_changes is true, | |
723 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
724 | |
725 | Arguments: | |
17c76198 | 726 | state exim_gnutls_state_st * |
059ec3d9 PH |
727 | |
728 | Returns: OK/DEFER/FAIL | |
729 | */ | |
730 | ||
731 | static int | |
17c76198 | 732 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 733 | { |
1365611d | 734 | struct stat statbuf; |
059ec3d9 | 735 | int rc; |
17c76198 PP |
736 | const host_item *host = state->host; /* macro should be reconsidered? */ |
737 | uschar *saved_tls_certificate = NULL; | |
738 | uschar *saved_tls_privatekey = NULL; | |
739 | uschar *saved_tls_verify_certificates = NULL; | |
740 | uschar *saved_tls_crl = NULL; | |
741 | int cert_count; | |
742 | ||
743 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 744 | if (!host) /* server */ |
17c76198 PP |
745 | { |
746 | if (!state->received_sni) | |
747 | { | |
d9b2312b JH |
748 | if (state->tls_certificate && |
749 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
750 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
751 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
752 | )) | |
17c76198 PP |
753 | { |
754 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
755 | state->trigger_sni_changes = TRUE; | |
756 | } | |
757 | } | |
758 | else | |
759 | { | |
1365611d | 760 | /* useful for debugging */ |
17c76198 PP |
761 | saved_tls_certificate = state->exp_tls_certificate; |
762 | saved_tls_privatekey = state->exp_tls_privatekey; | |
763 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
764 | saved_tls_crl = state->exp_tls_crl; | |
765 | } | |
766 | } | |
059ec3d9 | 767 | |
1365611d PP |
768 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
769 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
770 | ||
17c76198 PP |
771 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
772 | state members, assuming consistent naming; and expand_check() returns | |
773 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 774 | |
17c76198 PP |
775 | /* check if we at least have a certificate, before doing expensive |
776 | D-H generation. */ | |
059ec3d9 | 777 | |
17c76198 PP |
778 | if (!expand_check_tlsvar(tls_certificate)) |
779 | return DEFER; | |
059ec3d9 | 780 | |
17c76198 | 781 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 782 | |
17c76198 PP |
783 | if ((state->exp_tls_certificate == NULL) || |
784 | (*state->exp_tls_certificate == '\0')) | |
785 | { | |
2b4a568d | 786 | if (!host) |
17c76198 PP |
787 | return tls_error(US"no TLS server certificate is specified", NULL, NULL); |
788 | else | |
789 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
790 | } | |
059ec3d9 | 791 | |
17c76198 | 792 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
793 | return DEFER; |
794 | ||
17c76198 PP |
795 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
796 | ||
797 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 798 | { |
17c76198 PP |
799 | state->tls_privatekey = state->tls_certificate; |
800 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 801 | } |
c91535f3 | 802 | |
059ec3d9 | 803 | |
17c76198 | 804 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
805 | { |
806 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
807 | state->exp_tls_certificate, state->exp_tls_privatekey); |
808 | ||
809 | if (state->received_sni) | |
de365ded | 810 | { |
17c76198 PP |
811 | if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && |
812 | (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) | |
813 | { | |
b34fc30c | 814 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
815 | } |
816 | else | |
817 | { | |
b34fc30c | 818 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 819 | } |
8e669ac1 | 820 | } |
059ec3d9 | 821 | |
1365611d PP |
822 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
823 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
824 | GNUTLS_X509_FMT_PEM); | |
825 | exim_gnutls_err_check( | |
826 | string_sprintf("cert/key setup: cert=%s key=%s", | |
827 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
828 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 829 | } /* tls_certificate */ |
059ec3d9 | 830 | |
2b4a568d JH |
831 | |
832 | /* Set the OCSP stapling server info */ | |
833 | ||
f2de3a33 | 834 | #ifndef DISABLE_OCSP |
2b4a568d JH |
835 | if ( !host /* server */ |
836 | && tls_ocsp_file | |
837 | ) | |
838 | { | |
44662487 JH |
839 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", |
840 | &state->exp_tls_ocsp_file)) | |
2b4a568d JH |
841 | return DEFER; |
842 | ||
44662487 JH |
843 | /* Use the full callback method for stapling just to get observability. |
844 | More efficient would be to read the file once only, if it never changed | |
845 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
846 | ||
847 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, | |
848 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 849 | |
44662487 | 850 | DEBUG(D_tls) debug_printf("Set OCSP response file %s\n", &state->exp_tls_ocsp_file); |
2b4a568d JH |
851 | } |
852 | #endif | |
853 | ||
854 | ||
059ec3d9 PH |
855 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
856 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
857 | error message is provided. However, if we just refrain from setting anything up | |
858 | in that case, certificate verification fails, which seems to be the correct | |
859 | behaviour. */ | |
860 | ||
17c76198 | 861 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 862 | { |
17c76198 | 863 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 864 | return DEFER; |
17c76198 PP |
865 | if (state->tls_crl && *state->tls_crl) |
866 | if (!expand_check_tlsvar(tls_crl)) | |
867 | return DEFER; | |
059ec3d9 | 868 | |
1365611d PP |
869 | if (!(state->exp_tls_verify_certificates && |
870 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
871 | { |
872 | DEBUG(D_tls) | |
1365611d PP |
873 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
874 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 875 | return OK; |
b34fc30c | 876 | } |
1365611d | 877 | } |
83e2f8a2 PP |
878 | else |
879 | { | |
880 | DEBUG(D_tls) | |
881 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
882 | return OK; | |
883 | } | |
17c76198 | 884 | |
1365611d PP |
885 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
886 | { | |
887 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
888 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
889 | strerror(errno)); | |
890 | return DEFER; | |
891 | } | |
17c76198 | 892 | |
a7fec7a7 | 893 | #ifndef SUPPORT_CA_DIR |
619b2b25 PP |
894 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
895 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
896 | other weirdness. The thing we really want to check is that it's not a | |
897 | directory, since while OpenSSL supports that, GnuTLS does not. | |
898 | So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ | |
899 | if (S_ISDIR(statbuf.st_mode)) | |
1365611d PP |
900 | { |
901 | DEBUG(D_tls) | |
619b2b25 PP |
902 | debug_printf("verify certificates path is a dir: \"%s\"\n", |
903 | state->exp_tls_verify_certificates); | |
1365611d | 904 | log_write(0, LOG_MAIN|LOG_PANIC, |
619b2b25 | 905 | "tls_verify_certificates \"%s\" is a directory", |
1365611d PP |
906 | state->exp_tls_verify_certificates); |
907 | return DEFER; | |
908 | } | |
a7fec7a7 | 909 | #endif |
059ec3d9 | 910 | |
1365611d PP |
911 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
912 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 913 | |
1365611d PP |
914 | if (statbuf.st_size == 0) |
915 | { | |
916 | DEBUG(D_tls) | |
917 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
918 | return OK; | |
919 | } | |
059ec3d9 | 920 | |
a7fec7a7 JH |
921 | cert_count = |
922 | ||
923 | #ifdef SUPPORT_CA_DIR | |
924 | (statbuf.st_mode & S_IFMT) == S_IFDIR | |
925 | ? | |
926 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
927 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
928 | : | |
929 | #endif | |
930 | gnutls_certificate_set_x509_trust_file(state->x509_cred, | |
1365611d | 931 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); |
a7fec7a7 | 932 | |
1365611d PP |
933 | if (cert_count < 0) |
934 | { | |
935 | rc = cert_count; | |
936 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); | |
937 | } | |
938 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 939 | |
5c8cda3a PP |
940 | if (state->tls_crl && *state->tls_crl && |
941 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 942 | { |
5c8cda3a PP |
943 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
944 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
945 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
946 | if (cert_count < 0) | |
1365611d | 947 | { |
5c8cda3a | 948 | rc = cert_count; |
1365611d PP |
949 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
950 | } | |
5c8cda3a | 951 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 952 | } |
059ec3d9 | 953 | |
059ec3d9 PH |
954 | return OK; |
955 | } | |
956 | ||
957 | ||
958 | ||
959 | ||
1365611d PP |
960 | /************************************************* |
961 | * Set X.509 state variables * | |
962 | *************************************************/ | |
963 | ||
964 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
965 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
966 | structure. Which means various other non-re-expanded pieces of state | |
967 | need to be re-set in the new struct, so the setting logic is pulled | |
968 | out to this. | |
969 | ||
970 | Arguments: | |
971 | state exim_gnutls_state_st * | |
972 | ||
973 | Returns: OK/DEFER/FAIL | |
974 | */ | |
975 | ||
976 | static int | |
977 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
978 | { | |
979 | int rc; | |
980 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
981 | ||
982 | /* Create D-H parameters, or read them from the cache file. This function does | |
983 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
984 | client-side params. */ | |
985 | ||
986 | if (!state->host) | |
987 | { | |
988 | if (!dh_server_params) | |
989 | { | |
990 | rc = init_server_dh(); | |
991 | if (rc != OK) return rc; | |
992 | } | |
993 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
994 | } | |
995 | ||
996 | /* Link the credentials to the session. */ | |
997 | ||
998 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
999 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
1000 | ||
1001 | return OK; | |
1002 | } | |
1003 | ||
059ec3d9 | 1004 | /************************************************* |
17c76198 | 1005 | * Initialize for GnuTLS * |
059ec3d9 PH |
1006 | *************************************************/ |
1007 | ||
17c76198 PP |
1008 | /* Called from both server and client code. In the case of a server, errors |
1009 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1010 | |
1011 | Arguments: | |
17c76198 PP |
1012 | host connected host, if client; NULL if server |
1013 | certificate certificate file | |
1014 | privatekey private key file | |
1015 | sni TLS SNI to send, sometimes when client; else NULL | |
1016 | cas CA certs file | |
1017 | crl CRL file | |
1018 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1019 | caller_state returned state-info structure |
059ec3d9 | 1020 | |
17c76198 | 1021 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1022 | */ |
1023 | ||
17c76198 PP |
1024 | static int |
1025 | tls_init( | |
1026 | const host_item *host, | |
1027 | const uschar *certificate, | |
1028 | const uschar *privatekey, | |
1029 | const uschar *sni, | |
1030 | const uschar *cas, | |
1031 | const uschar *crl, | |
1032 | const uschar *require_ciphers, | |
1033 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 1034 | { |
17c76198 PP |
1035 | exim_gnutls_state_st *state; |
1036 | int rc; | |
1037 | size_t sz; | |
1038 | const char *errpos; | |
1039 | uschar *p; | |
1040 | BOOL want_default_priorities; | |
1041 | ||
1042 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1043 | { |
17c76198 PP |
1044 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1045 | ||
a5f239e4 PP |
1046 | #ifdef HAVE_GNUTLS_PKCS11 |
1047 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1048 | which loads modules from a config file, which sounds good and may be wanted | |
1049 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1050 | environment variables are used and so breaks for users calling mailq. | |
1051 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1052 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1053 | { |
1054 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1055 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1056 | } | |
1057 | #endif | |
1058 | ||
17c76198 PP |
1059 | rc = gnutls_global_init(); |
1060 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1061 | ||
1062 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1063 | DEBUG(D_tls) | |
059ec3d9 | 1064 | { |
17c76198 PP |
1065 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1066 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1067 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1068 | } |
17c76198 PP |
1069 | #endif |
1070 | ||
1071 | exim_gnutls_base_init_done = TRUE; | |
059ec3d9 | 1072 | } |
059ec3d9 | 1073 | |
17c76198 PP |
1074 | if (host) |
1075 | { | |
1076 | state = &state_client; | |
1077 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1078 | state->tlsp = &tls_out; |
17c76198 PP |
1079 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1080 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1081 | } | |
1082 | else | |
1083 | { | |
1084 | state = &state_server; | |
1085 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1086 | state->tlsp = &tls_in; |
17c76198 PP |
1087 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1088 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1089 | } | |
1090 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1091 | |
17c76198 | 1092 | state->host = host; |
059ec3d9 | 1093 | |
17c76198 PP |
1094 | state->tls_certificate = certificate; |
1095 | state->tls_privatekey = privatekey; | |
5779e6aa | 1096 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1097 | state->tls_sni = sni; |
1098 | state->tls_verify_certificates = cas; | |
1099 | state->tls_crl = crl; | |
059ec3d9 | 1100 | |
17c76198 PP |
1101 | /* This handles the variables that might get re-expanded after TLS SNI; |
1102 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1103 | |
17c76198 PP |
1104 | DEBUG(D_tls) |
1105 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
1106 | rc = tls_expand_session_files(state); | |
1107 | if (rc != OK) return rc; | |
059ec3d9 | 1108 | |
1365611d PP |
1109 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1110 | requires a new structure afterwards. */ | |
83da1223 | 1111 | |
1365611d PP |
1112 | rc = tls_set_remaining_x509(state); |
1113 | if (rc != OK) return rc; | |
83da1223 | 1114 | |
17c76198 PP |
1115 | /* set SNI in client, only */ |
1116 | if (host) | |
1117 | { | |
0df4ab80 | 1118 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni)) |
17c76198 | 1119 | return DEFER; |
0df4ab80 | 1120 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1121 | { |
1122 | DEBUG(D_tls) | |
0df4ab80 JH |
1123 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1124 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1125 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1126 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
17c76198 PP |
1127 | exim_gnutls_err_check(US"gnutls_server_name_set"); |
1128 | } | |
1129 | } | |
1130 | else if (state->tls_sni) | |
1131 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1132 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1133 | |
17c76198 | 1134 | /* This is the priority string support, |
42bfef1e | 1135 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1136 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1137 | This was backwards incompatible, but means Exim no longer needs to track | |
1138 | all algorithms and provide string forms for them. */ | |
83da1223 | 1139 | |
17c76198 | 1140 | want_default_priorities = TRUE; |
83da1223 | 1141 | |
17c76198 | 1142 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1143 | { |
17c76198 PP |
1144 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1145 | return DEFER; | |
1146 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1147 | { |
17c76198 PP |
1148 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1149 | state->exp_tls_require_ciphers); | |
1150 | ||
1151 | rc = gnutls_priority_init(&state->priority_cache, | |
1152 | CS state->exp_tls_require_ciphers, &errpos); | |
1153 | want_default_priorities = FALSE; | |
1154 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1155 | } |
1156 | } | |
17c76198 PP |
1157 | if (want_default_priorities) |
1158 | { | |
83e2f8a2 PP |
1159 | DEBUG(D_tls) |
1160 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1161 | exim_default_gnutls_priority); | |
17c76198 PP |
1162 | rc = gnutls_priority_init(&state->priority_cache, |
1163 | exim_default_gnutls_priority, &errpos); | |
1164 | p = US exim_default_gnutls_priority; | |
1165 | } | |
83da1223 | 1166 | |
17c76198 PP |
1167 | exim_gnutls_err_check(string_sprintf( |
1168 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1169 | p, errpos - CS p, errpos)); | |
1170 | ||
1171 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1172 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1173 | ||
1174 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1175 | ||
1176 | /* Reduce security in favour of increased compatibility, if the admin | |
1177 | decides to make that trade-off. */ | |
1178 | if (gnutls_compat_mode) | |
83da1223 | 1179 | { |
17c76198 PP |
1180 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1181 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1182 | gnutls_session_enable_compatibility_mode(state->session); | |
1183 | #else | |
1184 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1185 | #endif | |
83da1223 PH |
1186 | } |
1187 | ||
17c76198 | 1188 | *caller_state = state; |
17c76198 | 1189 | return OK; |
83da1223 PH |
1190 | } |
1191 | ||
1192 | ||
1193 | ||
059ec3d9 | 1194 | /************************************************* |
17c76198 | 1195 | * Extract peer information * |
059ec3d9 PH |
1196 | *************************************************/ |
1197 | ||
17c76198 | 1198 | /* Called from both server and client code. |
4fe99a6c PP |
1199 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1200 | and we use that to detect double-calls. | |
059ec3d9 | 1201 | |
75fe387d PP |
1202 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1203 | for logging in the server side, but for the client side, we log after teardown | |
1204 | in src/deliver.c. While the session is up, we can twist about states and | |
1205 | repoint tls_* globals, but those variables used for logging or other variable | |
1206 | expansion that happens _after_ delivery need to have a longer life-time. | |
1207 | ||
1208 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1209 | doing this more than once per generation of a state context. We set them in | |
1210 | the state context, and repoint tls_* to them. After the state goes away, the | |
1211 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1212 | ||
1213 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1214 | don't apply. | |
1215 | ||
059ec3d9 | 1216 | Arguments: |
17c76198 | 1217 | state exim_gnutls_state_st * |
059ec3d9 | 1218 | |
17c76198 | 1219 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1220 | */ |
1221 | ||
17c76198 PP |
1222 | static int |
1223 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1224 | { |
75fe387d | 1225 | uschar cipherbuf[256]; |
17c76198 | 1226 | const gnutls_datum *cert_list; |
75fe387d | 1227 | int old_pool, rc; |
17c76198 | 1228 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1229 | gnutls_protocol_t protocol; |
1230 | gnutls_cipher_algorithm_t cipher; | |
1231 | gnutls_kx_algorithm_t kx; | |
1232 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1233 | gnutls_certificate_type_t ct; |
1234 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1235 | uschar *p, *dn_buf; |
17c76198 | 1236 | size_t sz; |
059ec3d9 | 1237 | |
4fe99a6c | 1238 | if (state->have_set_peerdn) |
17c76198 | 1239 | return OK; |
4fe99a6c | 1240 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1241 | |
4fe99a6c | 1242 | state->peerdn = NULL; |
059ec3d9 | 1243 | |
4fe99a6c PP |
1244 | /* tls_cipher */ |
1245 | cipher = gnutls_cipher_get(state->session); | |
1246 | protocol = gnutls_protocol_get_version(state->session); | |
1247 | mac = gnutls_mac_get(state->session); | |
1248 | kx = gnutls_kx_get(state->session); | |
1249 | ||
75fe387d | 1250 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1251 | "%s:%s:%d", |
1252 | gnutls_protocol_get_name(protocol), | |
1253 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1254 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1255 | ||
1256 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1257 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1258 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1259 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1260 | if (isspace(*p)) |
1261 | *p = '-'; | |
75fe387d PP |
1262 | old_pool = store_pool; |
1263 | store_pool = POOL_PERM; | |
1264 | state->ciphersuite = string_copy(cipherbuf); | |
1265 | store_pool = old_pool; | |
817d9f57 | 1266 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1267 | |
1268 | /* tls_peerdn */ | |
17c76198 | 1269 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1270 | |
17c76198 PP |
1271 | if (cert_list == NULL || cert_list_size == 0) |
1272 | { | |
17c76198 PP |
1273 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1274 | cert_list, cert_list_size); | |
e51c7be2 | 1275 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1276 | return tls_error(US"certificate verification failed", |
1277 | "no certificate received from peer", state->host); | |
1278 | return OK; | |
1279 | } | |
059ec3d9 | 1280 | |
17c76198 PP |
1281 | ct = gnutls_certificate_type_get(state->session); |
1282 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1283 | { |
17c76198 | 1284 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1285 | DEBUG(D_tls) |
1286 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1287 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1288 | return tls_error(US"certificate verification not possible, unhandled type", |
1289 | ctn, state->host); | |
1290 | return OK; | |
83da1223 | 1291 | } |
059ec3d9 | 1292 | |
e51c7be2 JH |
1293 | #define exim_gnutls_peer_err(Label) \ |
1294 | do { \ | |
1295 | if (rc != GNUTLS_E_SUCCESS) \ | |
1296 | { \ | |
1297 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1298 | (Label), gnutls_strerror(rc)); \ | |
1299 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
1300 | return tls_error((Label), gnutls_strerror(rc), state->host); \ | |
1301 | return OK; \ | |
1302 | } \ | |
1303 | } while (0) | |
17c76198 | 1304 | |
9d1c15ef JH |
1305 | rc = import_cert(&cert_list[0], &crt); |
1306 | exim_gnutls_peer_err(US"cert 0"); | |
1307 | ||
1308 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1309 | |
17c76198 PP |
1310 | sz = 0; |
1311 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1312 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1313 | { |
17c76198 PP |
1314 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1315 | return FAIL; /* should not happen */ | |
059ec3d9 | 1316 | } |
17c76198 PP |
1317 | dn_buf = store_get_perm(sz); |
1318 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1319 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1320 | |
17c76198 PP |
1321 | state->peerdn = dn_buf; |
1322 | ||
1323 | return OK; | |
1324 | #undef exim_gnutls_peer_err | |
1325 | } | |
059ec3d9 | 1326 | |
059ec3d9 | 1327 | |
059ec3d9 | 1328 | |
059ec3d9 | 1329 | |
17c76198 PP |
1330 | /************************************************* |
1331 | * Verify peer certificate * | |
1332 | *************************************************/ | |
059ec3d9 | 1333 | |
17c76198 PP |
1334 | /* Called from both server and client code. |
1335 | *Should* be using a callback registered with | |
1336 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1337 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1338 | |
17c76198 PP |
1339 | Arguments: |
1340 | state exim_gnutls_state_st * | |
1341 | error where to put an error message | |
059ec3d9 | 1342 | |
17c76198 PP |
1343 | Returns: |
1344 | FALSE if the session should be rejected | |
1345 | TRUE if the cert is okay or we just don't care | |
1346 | */ | |
059ec3d9 | 1347 | |
17c76198 PP |
1348 | static BOOL |
1349 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1350 | { | |
1351 | int rc; | |
1352 | unsigned int verify; | |
1353 | ||
1354 | *error = NULL; | |
1355 | ||
0a92f87f | 1356 | if ((rc = peer_status(state)) != OK) |
e6060e2c | 1357 | { |
17c76198 | 1358 | verify = GNUTLS_CERT_INVALID; |
0a92f87f | 1359 | *error = "certificate not supplied"; |
17c76198 PP |
1360 | } |
1361 | else | |
17c76198 | 1362 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1363 | |
17c76198 PP |
1364 | /* Handle the result of verification. INVALID seems to be set as well |
1365 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1366 | |
e51c7be2 JH |
1367 | if (rc < 0 || |
1368 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1369 | ) | |
17c76198 PP |
1370 | { |
1371 | state->peer_cert_verified = FALSE; | |
0a92f87f JH |
1372 | if (!*error) |
1373 | *error = verify & GNUTLS_CERT_REVOKED | |
1374 | ? "certificate revoked" : "certificate invalid"; | |
059ec3d9 | 1375 | |
17c76198 | 1376 | DEBUG(D_tls) |
e51c7be2 | 1377 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
4fe99a6c | 1378 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1379 | |
e51c7be2 | 1380 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1381 | { |
e51c7be2 JH |
1382 | gnutls_alert_send(state->session, |
1383 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1384 | return FALSE; |
1385 | } | |
1386 | DEBUG(D_tls) | |
4789da3a | 1387 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1388 | } |
e51c7be2 | 1389 | |
17c76198 PP |
1390 | else |
1391 | { | |
e51c7be2 JH |
1392 | #ifdef EXPERIMENTAL_CERTNAMES |
1393 | if (state->verify_requirement == VERIFY_WITHHOST) | |
1394 | { | |
1395 | int sep = 0; | |
1396 | uschar * list = state->exp_tls_verify_cert_hostnames; | |
1397 | uschar * name; | |
1398 | while (name = string_nextinlist(&list, &sep, NULL, 0)) | |
1399 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) | |
1400 | break; | |
1401 | if (!name) | |
1402 | { | |
1403 | DEBUG(D_tls) | |
1404 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
1405 | gnutls_alert_send(state->session, | |
1406 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1407 | return FALSE; | |
1408 | } | |
1409 | } | |
1410 | #endif | |
17c76198 | 1411 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1412 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1413 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1414 | } |
059ec3d9 | 1415 | |
817d9f57 | 1416 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1417 | |
17c76198 PP |
1418 | return TRUE; |
1419 | } | |
059ec3d9 | 1420 | |
17c76198 PP |
1421 | |
1422 | ||
1423 | ||
1424 | /* ------------------------------------------------------------------------ */ | |
1425 | /* Callbacks */ | |
1426 | ||
1427 | /* Logging function which can be registered with | |
1428 | * gnutls_global_set_log_function() | |
1429 | * gnutls_global_set_log_level() 0..9 | |
1430 | */ | |
af3498d6 | 1431 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1432 | static void |
17c76198 | 1433 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1434 | { |
8c79eebf PP |
1435 | size_t len = strlen(message); |
1436 | if (len < 1) | |
1437 | { | |
1438 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1439 | return; | |
1440 | } | |
1441 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1442 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1443 | } |
af3498d6 | 1444 | #endif |
059ec3d9 | 1445 | |
059ec3d9 | 1446 | |
17c76198 PP |
1447 | /* Called after client hello, should handle SNI work. |
1448 | This will always set tls_sni (state->received_sni) if available, | |
1449 | and may trigger presenting different certificates, | |
1450 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1451 | |
17c76198 PP |
1452 | Should be registered with |
1453 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1454 | |
17c76198 PP |
1455 | "This callback must return 0 on success or a gnutls error code to terminate the |
1456 | handshake.". | |
059ec3d9 | 1457 | |
17c76198 PP |
1458 | For inability to get SNI information, we return 0. |
1459 | We only return non-zero if re-setup failed. | |
817d9f57 | 1460 | Only used for server-side TLS. |
17c76198 | 1461 | */ |
44bbabb5 | 1462 | |
17c76198 PP |
1463 | static int |
1464 | exim_sni_handling_cb(gnutls_session_t session) | |
1465 | { | |
1466 | char sni_name[MAX_HOST_LEN]; | |
1467 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1468 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1469 | unsigned int sni_type; |
1470 | int rc, old_pool; | |
1471 | ||
1472 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1473 | if (rc != GNUTLS_E_SUCCESS) |
1474 | { | |
1475 | DEBUG(D_tls) { | |
1476 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1477 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1478 | else | |
1479 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1480 | gnutls_strerror(rc), rc); | |
1481 | }; | |
1482 | return 0; | |
1483 | } | |
1484 | ||
17c76198 PP |
1485 | if (sni_type != GNUTLS_NAME_DNS) |
1486 | { | |
1487 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1488 | return 0; | |
1489 | } | |
44bbabb5 | 1490 | |
17c76198 PP |
1491 | /* We now have a UTF-8 string in sni_name */ |
1492 | old_pool = store_pool; | |
1493 | store_pool = POOL_PERM; | |
1494 | state->received_sni = string_copyn(US sni_name, data_len); | |
1495 | store_pool = old_pool; | |
1496 | ||
1497 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1498 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1499 | |
1500 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1501 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1502 | ||
1503 | if (!state->trigger_sni_changes) | |
1504 | return 0; | |
1505 | ||
1506 | rc = tls_expand_session_files(state); | |
1507 | if (rc != OK) | |
1508 | { | |
1509 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1510 | been offered. The best we can do now is abort. */ | |
1511 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1512 | } | |
1513 | ||
1365611d PP |
1514 | rc = tls_set_remaining_x509(state); |
1515 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1516 | ||
1517 | return 0; | |
059ec3d9 PH |
1518 | } |
1519 | ||
1520 | ||
1521 | ||
f2de3a33 | 1522 | #ifndef DISABLE_OCSP |
44662487 JH |
1523 | |
1524 | static int | |
1525 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1526 | gnutls_datum_t * ocsp_response) | |
1527 | { | |
1528 | int ret; | |
1529 | ||
44662487 JH |
1530 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1531 | { | |
1532 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
1533 | (char *)ptr); | |
018058b2 | 1534 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1535 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1536 | } | |
1537 | ||
018058b2 | 1538 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1539 | return 0; |
1540 | } | |
1541 | ||
1542 | #endif | |
1543 | ||
1544 | ||
a7538db1 JH |
1545 | #ifdef EXPERIMENTAL_TPDA |
1546 | /* | |
1547 | We use this callback to get observability and detail-level control | |
1548 | for an exim client TLS connection, raising a TPDA tls:cert event | |
1549 | for each cert in the chain presented by the server. Any event | |
1550 | can deny verification. | |
1551 | ||
1552 | Return 0 for the handshake to continue or non-zero to terminate. | |
1553 | */ | |
1554 | ||
1555 | static int | |
1556 | client_verify_cb(gnutls_session_t session) | |
1557 | { | |
1558 | const gnutls_datum * cert_list; | |
1559 | unsigned int cert_list_size = 0; | |
1560 | gnutls_x509_crt_t crt; | |
1561 | int rc; | |
1562 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); | |
1563 | ||
1564 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1565 | if (cert_list) | |
1566 | while (cert_list_size--) | |
1567 | { | |
1568 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1569 | if (rc != GNUTLS_E_SUCCESS) | |
1570 | { | |
1571 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1572 | cert_list_size, gnutls_strerror(rc)); | |
1573 | break; | |
1574 | } | |
1575 | ||
1576 | state->tlsp->peercert = crt; | |
1577 | if (tpda_raise_event(state->event_action, | |
1578 | US"tls:cert", string_sprintf("%d", cert_list_size)) == DEFER) | |
1579 | { | |
1580 | log_write(0, LOG_MAIN, | |
1581 | "SSL verify denied by event-action: depth=%d", cert_list_size); | |
1582 | return 1; /* reject */ | |
1583 | } | |
1584 | state->tlsp->peercert = NULL; | |
1585 | } | |
1586 | ||
1587 | return 0; | |
1588 | } | |
1589 | ||
1590 | #endif | |
44662487 JH |
1591 | |
1592 | ||
17c76198 PP |
1593 | |
1594 | /* ------------------------------------------------------------------------ */ | |
1595 | /* Exported functions */ | |
1596 | ||
1597 | ||
1598 | ||
1599 | ||
059ec3d9 PH |
1600 | /************************************************* |
1601 | * Start a TLS session in a server * | |
1602 | *************************************************/ | |
1603 | ||
1604 | /* This is called when Exim is running as a server, after having received | |
1605 | the STARTTLS command. It must respond to that command, and then negotiate | |
1606 | a TLS session. | |
1607 | ||
1608 | Arguments: | |
83da1223 | 1609 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1610 | |
1611 | Returns: OK on success | |
1612 | DEFER for errors before the start of the negotiation | |
1613 | FAIL for errors during the negotation; the server can't | |
1614 | continue running. | |
1615 | */ | |
1616 | ||
1617 | int | |
17c76198 | 1618 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1619 | { |
1620 | int rc; | |
7199e1ee | 1621 | const char *error; |
17c76198 | 1622 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1623 | |
1624 | /* Check for previous activation */ | |
817d9f57 | 1625 | if (tls_in.active >= 0) |
059ec3d9 | 1626 | { |
17c76198 | 1627 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1628 | smtp_printf("554 Already in TLS\r\n"); |
1629 | return FAIL; | |
1630 | } | |
1631 | ||
1632 | /* Initialize the library. If it fails, it will already have logged the error | |
1633 | and sent an SMTP response. */ | |
1634 | ||
17c76198 | 1635 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1636 | |
17c76198 PP |
1637 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1638 | NULL, tls_verify_certificates, tls_crl, | |
1639 | require_ciphers, &state); | |
059ec3d9 PH |
1640 | if (rc != OK) return rc; |
1641 | ||
059ec3d9 PH |
1642 | /* If this is a host for which certificate verification is mandatory or |
1643 | optional, set up appropriately. */ | |
1644 | ||
059ec3d9 | 1645 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1646 | { |
e51c7be2 JH |
1647 | DEBUG(D_tls) |
1648 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1649 | state->verify_requirement = VERIFY_REQUIRED; |
1650 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1651 | } | |
059ec3d9 | 1652 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1653 | { |
e51c7be2 JH |
1654 | DEBUG(D_tls) |
1655 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1656 | state->verify_requirement = VERIFY_OPTIONAL; |
1657 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1658 | } | |
1659 | else | |
1660 | { | |
e51c7be2 JH |
1661 | DEBUG(D_tls) |
1662 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1663 | state->verify_requirement = VERIFY_NONE; |
1664 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1665 | } | |
059ec3d9 | 1666 | |
17c76198 PP |
1667 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1668 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1669 | |
17c76198 PP |
1670 | gnutls_handshake_set_post_client_hello_function(state->session, |
1671 | exim_sni_handling_cb); | |
059ec3d9 PH |
1672 | |
1673 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1674 | on connection, where outputting anything now upsets the clients and tends to | |
1675 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1676 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1677 | mode, the fflush() happens when smtp_getc() is called. */ | |
1678 | ||
817d9f57 | 1679 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1680 | { |
1681 | smtp_printf("220 TLS go ahead\r\n"); | |
9d1c15ef | 1682 | fflush(smtp_out); |
059ec3d9 PH |
1683 | } |
1684 | ||
1685 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1686 | that the GnuTLS library doesn't. */ | |
1687 | ||
17c76198 | 1688 | gnutls_transport_set_ptr2(state->session, |
44662487 JH |
1689 | (gnutls_transport_ptr)(long) fileno(smtp_in), |
1690 | (gnutls_transport_ptr)(long) fileno(smtp_out)); | |
17c76198 PP |
1691 | state->fd_in = fileno(smtp_in); |
1692 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1693 | |
1694 | sigalrm_seen = FALSE; | |
1695 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 PP |
1696 | do |
1697 | { | |
1698 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1699 | } while ((rc == GNUTLS_E_AGAIN) || |
1700 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1701 | alarm(0); |
1702 | ||
17c76198 | 1703 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1704 | { |
17c76198 PP |
1705 | tls_error(US"gnutls_handshake", |
1706 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
059ec3d9 PH |
1707 | /* It seems that, except in the case of a timeout, we have to close the |
1708 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1709 | until the server times out. */ | |
1710 | ||
1711 | if (!sigalrm_seen) | |
1712 | { | |
f1e894f3 PH |
1713 | (void)fclose(smtp_out); |
1714 | (void)fclose(smtp_in); | |
059ec3d9 PH |
1715 | } |
1716 | ||
1717 | return FAIL; | |
1718 | } | |
1719 | ||
1720 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1721 | ||
17c76198 PP |
1722 | /* Verify after the fact */ |
1723 | ||
9d1c15ef JH |
1724 | if ( state->verify_requirement != VERIFY_NONE |
1725 | && !verify_certificate(state, &error)) | |
059ec3d9 | 1726 | { |
9d1c15ef | 1727 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1728 | { |
9d1c15ef JH |
1729 | tls_error(US"certificate verification failed", error, NULL); |
1730 | return FAIL; | |
17c76198 | 1731 | } |
9d1c15ef JH |
1732 | DEBUG(D_tls) |
1733 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1734 | error); | |
059ec3d9 PH |
1735 | } |
1736 | ||
17c76198 PP |
1737 | /* Figure out peer DN, and if authenticated, etc. */ |
1738 | ||
1739 | rc = peer_status(state); | |
1740 | if (rc != OK) return rc; | |
1741 | ||
1742 | /* Sets various Exim expansion variables; always safe within server */ | |
1743 | ||
9d1c15ef | 1744 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1745 | |
1746 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1747 | and initialize appropriately. */ | |
1748 | ||
17c76198 | 1749 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1750 | |
1751 | receive_getc = tls_getc; | |
1752 | receive_ungetc = tls_ungetc; | |
1753 | receive_feof = tls_feof; | |
1754 | receive_ferror = tls_ferror; | |
58eb016e | 1755 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1756 | |
059ec3d9 PH |
1757 | return OK; |
1758 | } | |
1759 | ||
1760 | ||
1761 | ||
1762 | ||
1763 | /************************************************* | |
1764 | * Start a TLS session in a client * | |
1765 | *************************************************/ | |
1766 | ||
1767 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1768 | ||
1769 | Arguments: | |
1770 | fd the fd of the connection | |
1771 | host connected host (for messages) | |
83da1223 | 1772 | addr the first address (not used) |
a7538db1 | 1773 | tb transport (always smtp) |
059ec3d9 PH |
1774 | |
1775 | Returns: OK/DEFER/FAIL (because using common functions), | |
1776 | but for a client, DEFER and FAIL have the same meaning | |
1777 | */ | |
1778 | ||
1779 | int | |
17c76198 | 1780 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1781 | address_item *addr ARG_UNUSED, |
0e66b3b6 JH |
1782 | transport_instance *tb |
1783 | #ifdef EXPERIMENTAL_DANE | |
1784 | , dne_answer * unused_tlsa_dnsa | |
1785 | #endif | |
1786 | ) | |
059ec3d9 | 1787 | { |
a7538db1 JH |
1788 | smtp_transport_options_block *ob = |
1789 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 1790 | int rc; |
17c76198 PP |
1791 | const char *error; |
1792 | exim_gnutls_state_st *state = NULL; | |
f2de3a33 | 1793 | #ifndef DISABLE_OCSP |
65867078 | 1794 | BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, |
2b4a568d | 1795 | NULL, host->name, host->address, NULL) == OK; |
44662487 JH |
1796 | BOOL request_ocsp = require_ocsp ? TRUE |
1797 | : verify_check_this_host(&ob->hosts_request_ocsp, | |
1798 | NULL, host->name, host->address, NULL) == OK; | |
2b4a568d | 1799 | #endif |
059ec3d9 | 1800 | |
17c76198 | 1801 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1802 | |
65867078 JH |
1803 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
1804 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
1805 | ob->tls_require_ciphers, &state)) != OK) | |
2b4a568d | 1806 | return rc; |
059ec3d9 | 1807 | |
54c90be1 | 1808 | { |
65867078 JH |
1809 | int dh_min_bits = ob->tls_dh_min_bits; |
1810 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
1811 | { | |
1812 | DEBUG(D_tls) | |
1813 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
1814 | " clamping %d up to %d\n", | |
1815 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1816 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1817 | } | |
54c90be1 | 1818 | |
65867078 JH |
1819 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
1820 | " acceptable bits to %d\n", | |
1821 | dh_min_bits); | |
1822 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
1823 | } | |
83da1223 | 1824 | |
2b4a568d JH |
1825 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
1826 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only | |
1827 | the specified host patterns if one of them is defined */ | |
1828 | ||
1829 | if (( state->exp_tls_verify_certificates | |
65867078 JH |
1830 | && !ob->tls_verify_hosts |
1831 | && !ob->tls_try_verify_hosts | |
2b4a568d JH |
1832 | ) |
1833 | || | |
65867078 | 1834 | verify_check_host(&ob->tls_verify_hosts) == OK |
2b4a568d | 1835 | ) |
17c76198 | 1836 | { |
e51c7be2 JH |
1837 | #ifdef EXPERIMENTAL_CERTNAMES |
1838 | if (ob->tls_verify_cert_hostnames) | |
1839 | { | |
1840 | DEBUG(D_tls) | |
1841 | debug_printf("TLS: server cert incl. hostname verification required.\n"); | |
1842 | state->verify_requirement = VERIFY_WITHHOST; | |
1843 | if (!expand_check(ob->tls_verify_cert_hostnames, | |
1844 | US"tls_verify_cert_hostnames", | |
1845 | &state->exp_tls_verify_cert_hostnames)) | |
1846 | return FAIL; | |
1847 | if (state->exp_tls_verify_cert_hostnames) | |
1848 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1849 | state->exp_tls_verify_cert_hostnames); | |
1850 | } | |
1851 | else | |
1852 | #endif | |
1853 | { | |
1854 | DEBUG(D_tls) | |
1855 | debug_printf("TLS: server certificate verification required.\n"); | |
1856 | state->verify_requirement = VERIFY_REQUIRED; | |
1857 | } | |
52f93eed WB |
1858 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
1859 | } | |
65867078 | 1860 | else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) |
52f93eed | 1861 | { |
e51c7be2 JH |
1862 | DEBUG(D_tls) |
1863 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 1864 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
1865 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
1866 | } | |
1867 | else | |
1868 | { | |
e51c7be2 JH |
1869 | DEBUG(D_tls) |
1870 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
1871 | state->verify_requirement = VERIFY_NONE; |
1872 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 1873 | } |
059ec3d9 | 1874 | |
f2de3a33 JH |
1875 | #ifndef DISABLE_OCSP |
1876 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 1877 | if (request_ocsp) |
9d1c15ef JH |
1878 | { |
1879 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
1880 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
1881 | NULL, 0, NULL)) != OK) | |
9d1c15ef JH |
1882 | return tls_error(US"cert-status-req", |
1883 | gnutls_strerror(rc), state->host); | |
44662487 | 1884 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 1885 | } |
2b4a568d JH |
1886 | #endif |
1887 | ||
a7538db1 JH |
1888 | #ifdef EXPERIMENTAL_TPDA |
1889 | if (tb->tpda_event_action) | |
1890 | { | |
1891 | state->event_action = tb->tpda_event_action; | |
1892 | gnutls_session_set_ptr(state->session, state); | |
1893 | gnutls_certificate_set_verify_function(state->x509_cred, client_verify_cb); | |
1894 | } | |
1895 | #endif | |
1896 | ||
44662487 | 1897 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)(long) fd); |
17c76198 PP |
1898 | state->fd_in = fd; |
1899 | state->fd_out = fd; | |
059ec3d9 | 1900 | |
9d1c15ef | 1901 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
1902 | /* There doesn't seem to be a built-in timeout on connection. */ |
1903 | ||
1904 | sigalrm_seen = FALSE; | |
65867078 | 1905 | alarm(ob->command_timeout); |
17c76198 PP |
1906 | do |
1907 | { | |
1908 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1909 | } while ((rc == GNUTLS_E_AGAIN) || |
1910 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1911 | alarm(0); |
1912 | ||
4fe99a6c PP |
1913 | if (rc != GNUTLS_E_SUCCESS) |
1914 | return tls_error(US"gnutls_handshake", | |
1915 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
1916 | ||
17c76198 | 1917 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 1918 | |
17c76198 | 1919 | /* Verify late */ |
059ec3d9 | 1920 | |
17c76198 PP |
1921 | if (state->verify_requirement != VERIFY_NONE && |
1922 | !verify_certificate(state, &error)) | |
1923 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 1924 | |
f2de3a33 | 1925 | #ifndef DISABLE_OCSP |
2b4a568d JH |
1926 | if (require_ocsp) |
1927 | { | |
1928 | DEBUG(D_tls) | |
1929 | { | |
1930 | gnutls_datum_t stapling; | |
1931 | gnutls_ocsp_resp_t resp; | |
1932 | gnutls_datum_t printed; | |
1933 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
1934 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
1935 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
1936 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
1937 | ) | |
1938 | { | |
65867078 | 1939 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
1940 | gnutls_free(printed.data); |
1941 | } | |
1942 | else | |
1943 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); | |
1944 | } | |
1945 | ||
2b4a568d | 1946 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
1947 | { |
1948 | tls_out.ocsp = OCSP_FAILED; | |
2b4a568d | 1949 | return tls_error(US"certificate status check failed", NULL, state->host); |
018058b2 | 1950 | } |
2b4a568d | 1951 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 1952 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
1953 | } |
1954 | #endif | |
1955 | ||
17c76198 | 1956 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 1957 | |
2b4a568d JH |
1958 | if ((rc = peer_status(state)) != OK) |
1959 | return rc; | |
059ec3d9 | 1960 | |
4fe99a6c | 1961 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 1962 | |
9d1c15ef | 1963 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 1964 | |
059ec3d9 PH |
1965 | return OK; |
1966 | } | |
1967 | ||
1968 | ||
1969 | ||
17c76198 | 1970 | |
059ec3d9 | 1971 | /************************************************* |
17c76198 | 1972 | * Close down a TLS session * |
059ec3d9 PH |
1973 | *************************************************/ |
1974 | ||
17c76198 PP |
1975 | /* This is also called from within a delivery subprocess forked from the |
1976 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1977 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 1978 | |
17c76198 PP |
1979 | Arguments: TRUE if gnutls_bye is to be called |
1980 | Returns: nothing | |
059ec3d9 PH |
1981 | */ |
1982 | ||
17c76198 | 1983 | void |
817d9f57 | 1984 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1985 | { |
817d9f57 | 1986 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1987 | |
389ca47a | 1988 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
1989 | |
1990 | if (shutdown) | |
1991 | { | |
1992 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1993 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
1994 | } | |
1995 | ||
1996 | gnutls_deinit(state->session); | |
1997 | ||
389ca47a | 1998 | state->tlsp->active = -1; |
17c76198 PP |
1999 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2000 | ||
2001 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2002 | { | |
2003 | gnutls_global_deinit(); | |
2004 | exim_gnutls_base_init_done = FALSE; | |
2005 | } | |
7199e1ee | 2006 | |
059ec3d9 PH |
2007 | } |
2008 | ||
2009 | ||
2010 | ||
17c76198 | 2011 | |
059ec3d9 PH |
2012 | /************************************************* |
2013 | * TLS version of getc * | |
2014 | *************************************************/ | |
2015 | ||
2016 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2017 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2018 | Only used by the server-side TLS. |
059ec3d9 | 2019 | |
17c76198 PP |
2020 | This feeds DKIM and should be used for all message-body reads. |
2021 | ||
059ec3d9 PH |
2022 | Arguments: none |
2023 | Returns: the next character or EOF | |
2024 | */ | |
2025 | ||
2026 | int | |
2027 | tls_getc(void) | |
2028 | { | |
817d9f57 | 2029 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 2030 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 2031 | { |
17c76198 | 2032 | ssize_t inbytes; |
059ec3d9 | 2033 | |
17c76198 PP |
2034 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
2035 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
2036 | |
2037 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 2038 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
2039 | ssl_xfer_buffer_size); |
2040 | alarm(0); | |
2041 | ||
2042 | /* A zero-byte return appears to mean that the TLS session has been | |
2043 | closed down, not that the socket itself has been closed down. Revert to | |
2044 | non-TLS handling. */ | |
2045 | ||
2046 | if (inbytes == 0) | |
2047 | { | |
2048 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2049 | ||
2050 | receive_getc = smtp_getc; | |
2051 | receive_ungetc = smtp_ungetc; | |
2052 | receive_feof = smtp_feof; | |
2053 | receive_ferror = smtp_ferror; | |
58eb016e | 2054 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 2055 | |
17c76198 PP |
2056 | gnutls_deinit(state->session); |
2057 | state->session = NULL; | |
817d9f57 JH |
2058 | state->tlsp->active = -1; |
2059 | state->tlsp->bits = 0; | |
2060 | state->tlsp->certificate_verified = FALSE; | |
9d1c15ef | 2061 | tls_channelbinding_b64 = NULL; |
817d9f57 | 2062 | state->tlsp->cipher = NULL; |
9d1c15ef | 2063 | state->tlsp->peercert = NULL; |
817d9f57 | 2064 | state->tlsp->peerdn = NULL; |
059ec3d9 PH |
2065 | |
2066 | return smtp_getc(); | |
2067 | } | |
2068 | ||
2069 | /* Handle genuine errors */ | |
2070 | ||
2071 | else if (inbytes < 0) | |
2072 | { | |
17c76198 PP |
2073 | record_io_error(state, (int) inbytes, US"recv", NULL); |
2074 | state->xfer_error = 1; | |
059ec3d9 PH |
2075 | return EOF; |
2076 | } | |
80a47a2c | 2077 | #ifndef DISABLE_DKIM |
17c76198 | 2078 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 2079 | #endif |
17c76198 PP |
2080 | state->xfer_buffer_hwm = (int) inbytes; |
2081 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
2082 | } |
2083 | ||
059ec3d9 PH |
2084 | /* Something in the buffer; return next uschar */ |
2085 | ||
17c76198 | 2086 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
2087 | } |
2088 | ||
2089 | ||
2090 | ||
17c76198 | 2091 | |
059ec3d9 PH |
2092 | /************************************************* |
2093 | * Read bytes from TLS channel * | |
2094 | *************************************************/ | |
2095 | ||
17c76198 PP |
2096 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2097 | then the caller must feed DKIM. | |
817d9f57 | 2098 | |
059ec3d9 PH |
2099 | Arguments: |
2100 | buff buffer of data | |
2101 | len size of buffer | |
2102 | ||
2103 | Returns: the number of bytes read | |
2104 | -1 after a failed read | |
2105 | */ | |
2106 | ||
2107 | int | |
817d9f57 | 2108 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2109 | { |
817d9f57 | 2110 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2111 | ssize_t inbytes; |
059ec3d9 | 2112 | |
17c76198 PP |
2113 | if (len > INT_MAX) |
2114 | len = INT_MAX; | |
059ec3d9 | 2115 | |
17c76198 PP |
2116 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2117 | DEBUG(D_tls) | |
2118 | debug_printf("*** PROBABLY A BUG *** " \ | |
2119 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2120 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2121 | ||
2122 | DEBUG(D_tls) | |
2123 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2124 | state->session, buff, len); | |
2125 | ||
2126 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2127 | if (inbytes > 0) return inbytes; |
2128 | if (inbytes == 0) | |
2129 | { | |
2130 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2131 | } | |
17c76198 | 2132 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2133 | |
2134 | return -1; | |
2135 | } | |
2136 | ||
2137 | ||
2138 | ||
17c76198 | 2139 | |
059ec3d9 PH |
2140 | /************************************************* |
2141 | * Write bytes down TLS channel * | |
2142 | *************************************************/ | |
2143 | ||
2144 | /* | |
2145 | Arguments: | |
817d9f57 | 2146 | is_server channel specifier |
059ec3d9 PH |
2147 | buff buffer of data |
2148 | len number of bytes | |
2149 | ||
2150 | Returns: the number of bytes after a successful write, | |
2151 | -1 after a failed write | |
2152 | */ | |
2153 | ||
2154 | int | |
817d9f57 | 2155 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 2156 | { |
17c76198 PP |
2157 | ssize_t outbytes; |
2158 | size_t left = len; | |
817d9f57 | 2159 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2160 | |
17c76198 | 2161 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
2162 | while (left > 0) |
2163 | { | |
17c76198 PP |
2164 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2165 | buff, left); | |
2166 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2167 | |
17c76198 | 2168 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2169 | if (outbytes < 0) |
2170 | { | |
17c76198 | 2171 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2172 | return -1; |
2173 | } | |
2174 | if (outbytes == 0) | |
2175 | { | |
17c76198 | 2176 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2177 | return -1; |
2178 | } | |
2179 | ||
2180 | left -= outbytes; | |
2181 | buff += outbytes; | |
2182 | } | |
2183 | ||
17c76198 PP |
2184 | if (len > INT_MAX) |
2185 | { | |
2186 | DEBUG(D_tls) | |
2187 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2188 | len); | |
2189 | len = INT_MAX; | |
2190 | } | |
2191 | ||
2192 | return (int) len; | |
059ec3d9 PH |
2193 | } |
2194 | ||
2195 | ||
2196 | ||
17c76198 | 2197 | |
059ec3d9 | 2198 | /************************************************* |
17c76198 | 2199 | * Random number generation * |
059ec3d9 PH |
2200 | *************************************************/ |
2201 | ||
17c76198 PP |
2202 | /* Pseudo-random number generation. The result is not expected to be |
2203 | cryptographically strong but not so weak that someone will shoot themselves | |
2204 | in the foot using it as a nonce in input in some email header scheme or | |
2205 | whatever weirdness they'll twist this into. The result should handle fork() | |
2206 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2207 | |
17c76198 PP |
2208 | Arguments: |
2209 | max range maximum | |
2210 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2211 | */ |
2212 | ||
af3498d6 | 2213 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2214 | int |
2215 | vaguely_random_number(int max) | |
059ec3d9 | 2216 | { |
17c76198 PP |
2217 | unsigned int r; |
2218 | int i, needed_len; | |
2219 | uschar *p; | |
2220 | uschar smallbuf[sizeof(r)]; | |
2221 | ||
2222 | if (max <= 1) | |
2223 | return 0; | |
2224 | ||
2225 | needed_len = sizeof(r); | |
2226 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2227 | * asked for a number less than 10. */ | |
2228 | for (r = max, i = 0; r; ++i) | |
2229 | r >>= 1; | |
2230 | i = (i + 7) / 8; | |
2231 | if (i < needed_len) | |
2232 | needed_len = i; | |
2233 | ||
2234 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2235 | if (i < 0) | |
059ec3d9 | 2236 | { |
17c76198 PP |
2237 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2238 | return vaguely_random_number_fallback(max); | |
2239 | } | |
2240 | r = 0; | |
2241 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2242 | { | |
2243 | r *= 256; | |
2244 | r += *p; | |
059ec3d9 PH |
2245 | } |
2246 | ||
17c76198 PP |
2247 | /* We don't particularly care about weighted results; if someone wants |
2248 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2249 | return r % max; | |
059ec3d9 | 2250 | } |
af3498d6 PP |
2251 | #else /* HAVE_GNUTLS_RND */ |
2252 | int | |
2253 | vaguely_random_number(int max) | |
2254 | { | |
2255 | return vaguely_random_number_fallback(max); | |
2256 | } | |
2257 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2258 | |
36f12725 NM |
2259 | |
2260 | ||
2261 | ||
3375e053 PP |
2262 | /************************************************* |
2263 | * Let tls_require_ciphers be checked at startup * | |
2264 | *************************************************/ | |
2265 | ||
2266 | /* The tls_require_ciphers option, if set, must be something which the | |
2267 | library can parse. | |
2268 | ||
2269 | Returns: NULL on success, or error message | |
2270 | */ | |
2271 | ||
2272 | uschar * | |
2273 | tls_validate_require_cipher(void) | |
2274 | { | |
2275 | int rc; | |
2276 | uschar *expciphers = NULL; | |
2277 | gnutls_priority_t priority_cache; | |
2278 | const char *errpos; | |
2279 | ||
2280 | #define validate_check_rc(Label) do { \ | |
2281 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2282 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2283 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2284 | ||
2285 | if (exim_gnutls_base_init_done) | |
2286 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2287 | "already initialised GnuTLS, Exim developer bug"); | |
2288 | ||
a5f239e4 | 2289 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2290 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2291 | { |
2292 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2293 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2294 | } | |
2295 | #endif | |
3375e053 PP |
2296 | rc = gnutls_global_init(); |
2297 | validate_check_rc(US"gnutls_global_init()"); | |
2298 | exim_gnutls_base_init_done = TRUE; | |
2299 | ||
2300 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2301 | return_deinit(NULL); | |
2302 | ||
2303 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2304 | return_deinit(US"failed to expand tls_require_ciphers"); | |
2305 | ||
2306 | if (!(expciphers && *expciphers)) | |
2307 | return_deinit(NULL); | |
2308 | ||
2309 | DEBUG(D_tls) | |
2310 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2311 | ||
2312 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2313 | validate_check_rc(string_sprintf( | |
2314 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2315 | expciphers, errpos - CS expciphers, errpos)); | |
2316 | ||
2317 | #undef return_deinit | |
2318 | #undef validate_check_rc | |
2319 | gnutls_global_deinit(); | |
2320 | ||
2321 | return NULL; | |
2322 | } | |
2323 | ||
2324 | ||
2325 | ||
2326 | ||
36f12725 NM |
2327 | /************************************************* |
2328 | * Report the library versions. * | |
2329 | *************************************************/ | |
2330 | ||
2331 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2332 | ||
2333 | Arguments: a FILE* to print the results to | |
2334 | Returns: nothing | |
2335 | */ | |
2336 | ||
2337 | void | |
2338 | tls_version_report(FILE *f) | |
2339 | { | |
754a0503 PP |
2340 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2341 | " Runtime: %s\n", | |
2342 | LIBGNUTLS_VERSION, | |
2343 | gnutls_check_version(NULL)); | |
36f12725 NM |
2344 | } |
2345 | ||
2b4a568d JH |
2346 | /* vi: aw ai sw=2 |
2347 | */ | |
059ec3d9 | 2348 | /* End of tls-gnu.c */ |