Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
3386088d | 5 | /* Copyright (c) University of Cambridge 1995 - 2015 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
17c76198 | 8 | /* Copyright (c) Phil Pennock 2012 */ |
059ec3d9 | 9 | |
17c76198 PP |
10 | /* This file provides TLS/SSL support for Exim using the GnuTLS library, |
11 | one of the available supported implementations. This file is #included into | |
12 | tls.c when USE_GNUTLS has been set. | |
059ec3d9 | 13 | |
17c76198 PP |
14 | The code herein is a revamp of GnuTLS integration using the current APIs; the |
15 | original tls-gnu.c was based on a patch which was contributed by Nikos | |
6aa6fc9c | 16 | Mavrogiannopoulos. The revamp is partially a rewrite, partially cut&paste as |
17c76198 | 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> | |
76075bb5 | 45 | # define SUPPORT_PARAM_TO_PK_BITS |
a5f239e4 | 46 | #endif |
7e07527a JH |
47 | #if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) |
48 | # warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" | |
49 | # define DISABLE_OCSP | |
50 | #endif | |
0cbf2b82 | 51 | #if GNUTLS_VERSION_NUMBER < 0x020a00 && !defined(DISABLE_EVENT) |
774ef2d7 | 52 | # warning "GnuTLS library version too old; tls:cert event unsupported" |
0cbf2b82 | 53 | # define DISABLE_EVENT |
a7538db1 | 54 | #endif |
a7fec7a7 JH |
55 | #if GNUTLS_VERSION_NUMBER >= 0x030306 |
56 | # define SUPPORT_CA_DIR | |
57 | #else | |
58 | # undef SUPPORT_CA_DIR | |
59 | #endif | |
11a04b5a | 60 | #if GNUTLS_VERSION_NUMBER >= 0x030014 |
cb1d7830 JH |
61 | # define SUPPORT_SYSDEFAULT_CABUNDLE |
62 | #endif | |
925ac8e4 JH |
63 | #if GNUTLS_VERSION_NUMBER >= 0x030109 |
64 | # define SUPPORT_CORK | |
65 | #endif | |
7e07527a | 66 | |
f2de3a33 | 67 | #ifndef DISABLE_OCSP |
2b4a568d JH |
68 | # include <gnutls/ocsp.h> |
69 | #endif | |
059ec3d9 | 70 | |
17c76198 | 71 | /* GnuTLS 2 vs 3 |
059ec3d9 | 72 | |
17c76198 PP |
73 | GnuTLS 3 only: |
74 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 75 | |
17c76198 PP |
76 | Changes: |
77 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
78 | */ | |
059ec3d9 | 79 | |
17c76198 | 80 | /* Local static variables for GnuTLS */ |
059ec3d9 | 81 | |
17c76198 | 82 | /* Values for verify_requirement */ |
059ec3d9 | 83 | |
e51c7be2 | 84 | enum peer_verify_requirement |
aa2a70ba | 85 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 86 | |
17c76198 PP |
87 | /* This holds most state for server or client; with this, we can set up an |
88 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
89 | over the TLS variables available for expansion. | |
059ec3d9 | 90 | |
17c76198 PP |
91 | Some of these correspond to variables in globals.c; those variables will |
92 | be set to point to content in one of these instances, as appropriate for | |
93 | the stage of the process lifetime. | |
059ec3d9 | 94 | |
389ca47a | 95 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 96 | */ |
059ec3d9 | 97 | |
17c76198 | 98 | typedef struct exim_gnutls_state { |
9d1c15ef | 99 | gnutls_session_t session; |
17c76198 | 100 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 101 | gnutls_priority_t priority_cache; |
17c76198 | 102 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
103 | int fd_in; |
104 | int fd_out; | |
105 | BOOL peer_cert_verified; | |
106 | BOOL trigger_sni_changes; | |
107 | BOOL have_set_peerdn; | |
17c76198 | 108 | const struct host_item *host; |
9d1c15ef JH |
109 | gnutls_x509_crt_t peercert; |
110 | uschar *peerdn; | |
111 | uschar *ciphersuite; | |
112 | uschar *received_sni; | |
17c76198 PP |
113 | |
114 | const uschar *tls_certificate; | |
115 | const uschar *tls_privatekey; | |
116 | const uschar *tls_sni; /* client send only, not received */ | |
117 | const uschar *tls_verify_certificates; | |
118 | const uschar *tls_crl; | |
119 | const uschar *tls_require_ciphers; | |
e51c7be2 | 120 | |
17c76198 PP |
121 | uschar *exp_tls_certificate; |
122 | uschar *exp_tls_privatekey; | |
17c76198 PP |
123 | uschar *exp_tls_verify_certificates; |
124 | uschar *exp_tls_crl; | |
125 | uschar *exp_tls_require_ciphers; | |
44662487 | 126 | uschar *exp_tls_ocsp_file; |
55414b25 | 127 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 128 | #ifndef DISABLE_EVENT |
a7538db1 JH |
129 | uschar *event_action; |
130 | #endif | |
17c76198 | 131 | |
389ca47a | 132 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 133 | |
17c76198 PP |
134 | uschar *xfer_buffer; |
135 | int xfer_buffer_lwm; | |
136 | int xfer_buffer_hwm; | |
137 | int xfer_eof; | |
138 | int xfer_error; | |
17c76198 PP |
139 | } exim_gnutls_state_st; |
140 | ||
141 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 142 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 143 | NULL, NULL, NULL, NULL, |
17c76198 | 144 | NULL, NULL, NULL, NULL, NULL, NULL, |
44662487 | 145 | NULL, NULL, NULL, NULL, NULL, NULL, NULL, |
01a4a5c5 | 146 | NULL, |
0cbf2b82 | 147 | #ifndef DISABLE_EVENT |
a7538db1 | 148 | NULL, |
e51c7be2 | 149 | #endif |
817d9f57 | 150 | NULL, |
17c76198 | 151 | NULL, 0, 0, 0, 0, |
17c76198 | 152 | }; |
83da1223 | 153 | |
17c76198 PP |
154 | /* Not only do we have our own APIs which don't pass around state, assuming |
155 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
156 | for callbacks, or as part of the session, so we have to keep a "this is the | |
157 | context we're currently dealing with" pointer and rely upon being | |
158 | single-threaded to keep from processing data on an inbound TLS connection while | |
159 | talking to another TLS connection for an outbound check. This does mean that | |
160 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
161 | second connection. |
162 | XXX But see gnutls_session_get_ptr() | |
163 | */ | |
059ec3d9 | 164 | |
17c76198 | 165 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 166 | |
17c76198 PP |
167 | /* dh_params are initialised once within the lifetime of a process using TLS; |
168 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
169 | don't want to repeat this. */ | |
83da1223 | 170 | |
17c76198 | 171 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 172 | |
17c76198 | 173 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 174 | |
17c76198 | 175 | static const int ssl_session_timeout = 200; |
059ec3d9 | 176 | |
17c76198 | 177 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 178 | |
17c76198 | 179 | /* Guard library core initialisation */ |
83da1223 | 180 | |
17c76198 | 181 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 182 | |
4fb7df6d | 183 | #ifndef DISABLE_OCSP |
9196d5bf | 184 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 185 | #endif |
9196d5bf | 186 | |
059ec3d9 | 187 | |
17c76198 PP |
188 | /* ------------------------------------------------------------------------ */ |
189 | /* macros */ | |
83da1223 | 190 | |
17c76198 | 191 | #define MAX_HOST_LEN 255 |
83da1223 | 192 | |
17c76198 PP |
193 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
194 | the library logging; a value less than 0 disables the calls to set up logging | |
195 | callbacks. */ | |
2c17bb02 | 196 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 197 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 198 | #endif |
83da1223 | 199 | |
2c17bb02 | 200 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 201 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 202 | #endif |
83da1223 | 203 | |
af3498d6 PP |
204 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
205 | can ask for a bit-strength. Without that, we stick to the constant we had | |
206 | before, for now. */ | |
2c17bb02 | 207 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 208 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 209 | #endif |
af3498d6 | 210 | |
17c76198 | 211 | #define exim_gnutls_err_check(Label) do { \ |
cf0c6164 JH |
212 | if (rc != GNUTLS_E_SUCCESS) \ |
213 | return tls_error((Label), gnutls_strerror(rc), host, errstr); \ | |
214 | } while (0) | |
059ec3d9 | 215 | |
cf0c6164 JH |
216 | #define expand_check_tlsvar(Varname, errstr) \ |
217 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 218 | |
17c76198 | 219 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
220 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
221 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
222 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
223 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
224 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
225 | * isn't available sometimes, so this needs to become a conditional | |
226 | * compilation; the sanest way to deal with this being a problem on | |
227 | * older OSes is to block it in the Local/Makefile with this compiler | |
228 | * definition */ | |
e51c7be2 JH |
229 | # ifndef AVOID_GNUTLS_PKCS11 |
230 | # define HAVE_GNUTLS_PKCS11 | |
231 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 232 | #endif |
83da1223 | 233 | |
af3498d6 PP |
234 | |
235 | ||
236 | ||
237 | /* ------------------------------------------------------------------------ */ | |
238 | /* Callback declarations */ | |
239 | ||
240 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
241 | static void exim_gnutls_logger_cb(int level, const char *message); | |
242 | #endif | |
243 | ||
244 | static int exim_sni_handling_cb(gnutls_session_t session); | |
245 | ||
f2de3a33 | 246 | #ifndef DISABLE_OCSP |
44662487 JH |
247 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
248 | gnutls_datum_t * ocsp_response); | |
249 | #endif | |
af3498d6 PP |
250 | |
251 | ||
252 | ||
17c76198 PP |
253 | /* ------------------------------------------------------------------------ */ |
254 | /* Static functions */ | |
059ec3d9 PH |
255 | |
256 | /************************************************* | |
257 | * Handle TLS error * | |
258 | *************************************************/ | |
259 | ||
260 | /* Called from lots of places when errors occur before actually starting to do | |
261 | the TLS handshake, that is, while the session is still in clear. Always returns | |
262 | DEFER for a server and FAIL for a client so that most calls can use "return | |
263 | tls_error(...)" to do this processing and then give an appropriate return. A | |
264 | single function is used for both server and client, because it is called from | |
265 | some shared functions. | |
266 | ||
267 | Argument: | |
268 | prefix text to include in the logged error | |
7199e1ee TF |
269 | msg additional error string (may be NULL) |
270 | usually obtained from gnutls_strerror() | |
17c76198 PP |
271 | host NULL if setting up a server; |
272 | the connected host if setting up a client | |
cf0c6164 | 273 | errstr pointer to returned error string |
059ec3d9 PH |
274 | |
275 | Returns: OK/DEFER/FAIL | |
276 | */ | |
277 | ||
278 | static int | |
cf0c6164 JH |
279 | tls_error(const uschar *prefix, const char *msg, const host_item *host, |
280 | uschar ** errstr) | |
059ec3d9 | 281 | { |
cf0c6164 JH |
282 | if (errstr) |
283 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); | |
284 | return host ? FAIL : DEFER; | |
059ec3d9 PH |
285 | } |
286 | ||
287 | ||
288 | ||
17c76198 | 289 | |
059ec3d9 | 290 | /************************************************* |
17c76198 | 291 | * Deal with logging errors during I/O * |
059ec3d9 PH |
292 | *************************************************/ |
293 | ||
17c76198 | 294 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 295 | |
17c76198 PP |
296 | Argument: |
297 | state the current GnuTLS exim state container | |
298 | rc the GnuTLS error code, or 0 if it's a local error | |
299 | when text identifying read or write | |
300 | text local error text when ec is 0 | |
059ec3d9 | 301 | |
17c76198 | 302 | Returns: nothing |
059ec3d9 PH |
303 | */ |
304 | ||
17c76198 PP |
305 | static void |
306 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 307 | { |
cf0c6164 JH |
308 | const char * msg; |
309 | uschar * errstr; | |
059ec3d9 | 310 | |
17c76198 PP |
311 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
312 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
313 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
314 | else | |
315 | msg = gnutls_strerror(rc); | |
059ec3d9 | 316 | |
cf0c6164 JH |
317 | (void) tls_error(when, msg, state->host, &errstr); |
318 | ||
319 | if (state->host) | |
320 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
321 | state->host->name, state->host->address, errstr); | |
322 | else | |
323 | { | |
324 | uschar * conn_info = smtp_get_connection_info(); | |
325 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
326 | /* I'd like to get separated H= here, but too hard for now */ | |
327 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
328 | } | |
17c76198 | 329 | } |
059ec3d9 | 330 | |
059ec3d9 | 331 | |
059ec3d9 | 332 | |
059ec3d9 | 333 | |
17c76198 PP |
334 | /************************************************* |
335 | * Set various Exim expansion vars * | |
336 | *************************************************/ | |
059ec3d9 | 337 | |
e51c7be2 JH |
338 | #define exim_gnutls_cert_err(Label) \ |
339 | do \ | |
340 | { \ | |
341 | if (rc != GNUTLS_E_SUCCESS) \ | |
342 | { \ | |
343 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
344 | (Label), gnutls_strerror(rc)); \ | |
345 | return rc; \ | |
346 | } \ | |
347 | } while (0) | |
9d1c15ef JH |
348 | |
349 | static int | |
27f19eb4 | 350 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
351 | { |
352 | int rc; | |
353 | ||
354 | rc = gnutls_x509_crt_init(crtp); | |
355 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
356 | ||
357 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
358 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
359 | ||
360 | return rc; | |
361 | } | |
362 | ||
363 | #undef exim_gnutls_cert_err | |
364 | ||
365 | ||
17c76198 PP |
366 | /* We set various Exim global variables from the state, once a session has |
367 | been established. With TLS callouts, may need to change this to stack | |
368 | variables, or just re-call it with the server state after client callout | |
369 | has finished. | |
059ec3d9 | 370 | |
9d1c15ef | 371 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
372 | |
373 | Sets: | |
374 | tls_active fd | |
375 | tls_bits strength indicator | |
376 | tls_certificate_verified bool indicator | |
377 | tls_channelbinding_b64 for some SASL mechanisms | |
378 | tls_cipher a string | |
9d1c15ef | 379 | tls_peercert pointer to library internal |
17c76198 PP |
380 | tls_peerdn a string |
381 | tls_sni a (UTF-8) string | |
9d1c15ef | 382 | tls_ourcert pointer to library internal |
17c76198 PP |
383 | |
384 | Argument: | |
385 | state the relevant exim_gnutls_state_st * | |
386 | */ | |
387 | ||
388 | static void | |
9d1c15ef | 389 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 390 | { |
17c76198 | 391 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
392 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
393 | int old_pool; | |
394 | int rc; | |
395 | gnutls_datum_t channel; | |
396 | #endif | |
9d1c15ef | 397 | tls_support * tlsp = state->tlsp; |
17c76198 | 398 | |
9d1c15ef | 399 | tlsp->active = state->fd_out; |
17c76198 PP |
400 | |
401 | cipher = gnutls_cipher_get(state->session); | |
402 | /* returns size in "bytes" */ | |
9d1c15ef | 403 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 404 | |
9d1c15ef | 405 | tlsp->cipher = state->ciphersuite; |
17c76198 | 406 | |
817d9f57 | 407 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 408 | |
9d1c15ef | 409 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 410 | |
17c76198 PP |
411 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
412 | only available for use for authenticators while this TLS session is running. */ | |
413 | ||
414 | tls_channelbinding_b64 = NULL; | |
415 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
416 | channel.data = NULL; | |
417 | channel.size = 0; | |
418 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
419 | if (rc) { | |
420 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
421 | } else { | |
422 | old_pool = store_pool; | |
423 | store_pool = POOL_PERM; | |
f4d091fb | 424 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
425 | store_pool = old_pool; |
426 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
427 | } | |
428 | #endif | |
429 | ||
9d1c15ef JH |
430 | /* peercert is set in peer_status() */ |
431 | tlsp->peerdn = state->peerdn; | |
432 | tlsp->sni = state->received_sni; | |
433 | ||
434 | /* record our certificate */ | |
435 | { | |
27f19eb4 | 436 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
437 | gnutls_x509_crt_t crt; |
438 | ||
439 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
440 | } | |
059ec3d9 PH |
441 | } |
442 | ||
443 | ||
444 | ||
17c76198 | 445 | |
059ec3d9 | 446 | /************************************************* |
575643cd | 447 | * Setup up DH parameters * |
059ec3d9 PH |
448 | *************************************************/ |
449 | ||
575643cd | 450 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
451 | be re-generated every so often, depending on security policy. What we do is to |
452 | keep these parameters in a file in the spool directory. If the file does not | |
453 | exist, we generate them. This means that it is easy to cause a regeneration. | |
454 | ||
455 | The new file is written as a temporary file and renamed, so that an incomplete | |
456 | file is never present. If two processes both compute some new parameters, you | |
457 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
458 | prevent this. | |
459 | ||
059ec3d9 PH |
460 | Returns: OK/DEFER/FAIL |
461 | */ | |
462 | ||
463 | static int | |
cf0c6164 | 464 | init_server_dh(uschar ** errstr) |
059ec3d9 | 465 | { |
17c76198 PP |
466 | int fd, rc; |
467 | unsigned int dh_bits; | |
27f19eb4 | 468 | gnutls_datum_t m; |
a799883d PP |
469 | uschar filename_buf[PATH_MAX]; |
470 | uschar *filename = NULL; | |
17c76198 | 471 | size_t sz; |
a799883d PP |
472 | uschar *exp_tls_dhparam; |
473 | BOOL use_file_in_spool = FALSE; | |
474 | BOOL use_fixed_file = FALSE; | |
17c76198 | 475 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 476 | |
17c76198 | 477 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 478 | |
17c76198 PP |
479 | rc = gnutls_dh_params_init(&dh_server_params); |
480 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 481 | |
a799883d PP |
482 | m.data = NULL; |
483 | m.size = 0; | |
484 | ||
cf0c6164 | 485 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
486 | return DEFER; |
487 | ||
488 | if (!exp_tls_dhparam) | |
489 | { | |
490 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
491 | m.data = US std_dh_prime_default(); | |
492 | m.size = Ustrlen(m.data); | |
493 | } | |
494 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
495 | use_file_in_spool = TRUE; | |
496 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
497 | { | |
498 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
499 | return OK; | |
500 | } | |
501 | else if (exp_tls_dhparam[0] != '/') | |
502 | { | |
f5d25c2b | 503 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
cf0c6164 | 504 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); |
a799883d PP |
505 | m.size = Ustrlen(m.data); |
506 | } | |
507 | else | |
508 | { | |
509 | use_fixed_file = TRUE; | |
510 | filename = exp_tls_dhparam; | |
511 | } | |
512 | ||
513 | if (m.data) | |
514 | { | |
515 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
516 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
517 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
518 | return OK; | |
519 | } | |
520 | ||
af3498d6 PP |
521 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
522 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
523 | different filename and ensure we have sufficient bits. */ |
524 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
525 | if (!dh_bits) | |
cf0c6164 | 526 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 527 | DEBUG(D_tls) |
b34fc30c | 528 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
529 | dh_bits); |
530 | #else | |
531 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
532 | DEBUG(D_tls) | |
533 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
534 | dh_bits); | |
535 | #endif | |
059ec3d9 | 536 | |
3375e053 PP |
537 | /* Some clients have hard-coded limits. */ |
538 | if (dh_bits > tls_dh_max_bits) | |
539 | { | |
540 | DEBUG(D_tls) | |
541 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
542 | tls_dh_max_bits); | |
543 | dh_bits = tls_dh_max_bits; | |
544 | } | |
545 | ||
a799883d PP |
546 | if (use_file_in_spool) |
547 | { | |
548 | if (!string_format(filename_buf, sizeof(filename_buf), | |
549 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 550 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
551 | filename = filename_buf; |
552 | } | |
059ec3d9 | 553 | |
b5aea5e1 | 554 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 555 | parameters. */ |
059ec3d9 | 556 | |
f5d25c2b | 557 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 558 | { |
b5aea5e1 | 559 | struct stat statbuf; |
17c76198 PP |
560 | FILE *fp; |
561 | int saved_errno; | |
562 | ||
563 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
564 | { | |
565 | saved_errno = errno; | |
566 | (void)close(fd); | |
cf0c6164 | 567 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
568 | } |
569 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
570 | { |
571 | (void)close(fd); | |
cf0c6164 | 572 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 573 | } |
40c90bca | 574 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
575 | { |
576 | saved_errno = errno; | |
577 | (void)close(fd); | |
578 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
cf0c6164 | 579 | strerror(saved_errno), NULL, errstr); |
b5aea5e1 | 580 | } |
059ec3d9 | 581 | |
b5aea5e1 | 582 | m.size = statbuf.st_size; |
40c90bca | 583 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
584 | { |
585 | fclose(fp); | |
cf0c6164 | 586 | return tls_error(US"malloc failed", strerror(errno), NULL, errstr); |
17c76198 | 587 | } |
40c90bca | 588 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
589 | { |
590 | saved_errno = errno; | |
591 | fclose(fp); | |
592 | free(m.data); | |
cf0c6164 | 593 | return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
594 | } |
595 | fclose(fp); | |
b5aea5e1 | 596 | |
17c76198 | 597 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 598 | free(m.data); |
17c76198 PP |
599 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
600 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
601 | } |
602 | ||
603 | /* If the file does not exist, fall through to compute new data and cache it. | |
604 | If there was any other opening error, it is serious. */ | |
605 | ||
182ad5cf PH |
606 | else if (errno == ENOENT) |
607 | { | |
17c76198 | 608 | rc = -1; |
182ad5cf | 609 | DEBUG(D_tls) |
17c76198 | 610 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
611 | } |
612 | else | |
17c76198 | 613 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 614 | NULL, NULL, errstr); |
b5aea5e1 PH |
615 | |
616 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
617 | is not useful. One particular case of this is when upgrading from an older | |
618 | release of Exim in which the data was stored in a different format. We don't | |
619 | try to be clever and support both formats; we just regenerate new data in this | |
620 | case. */ | |
621 | ||
17c76198 | 622 | if (rc < 0) |
b5aea5e1 | 623 | { |
17c76198 | 624 | uschar *temp_fn; |
201f5254 | 625 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 626 | |
17c76198 PP |
627 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
628 | return tls_error(US"Filename too long to generate replacement", | |
cf0c6164 | 629 | CS filename, NULL, errstr); |
059ec3d9 | 630 | |
17c76198 | 631 | temp_fn = string_copy(US "%s.XXXXXXX"); |
f5d25c2b | 632 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
cf0c6164 | 633 | return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); |
059ec3d9 PH |
634 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
635 | ||
201f5254 PP |
636 | /* GnuTLS overshoots! |
637 | * If we ask for 2236, we might get 2237 or more. | |
638 | * But there's no way to ask GnuTLS how many bits there really are. | |
639 | * We can ask how many bits were used in a TLS session, but that's it! | |
640 | * The prime itself is hidden behind too much abstraction. | |
641 | * So we ask for less, and proceed on a wing and a prayer. | |
642 | * First attempt, subtracted 3 for 2233 and got 2240. | |
643 | */ | |
cae6e576 | 644 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
645 | { |
646 | dh_bits_gen = dh_bits - 10; | |
647 | DEBUG(D_tls) | |
648 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
649 | dh_bits_gen); | |
650 | } | |
651 | ||
652 | DEBUG(D_tls) | |
653 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
654 | dh_bits_gen); | |
655 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
656 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
657 | ||
658 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
659 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
660 | sample apps handle this. */ | |
661 | ||
662 | sz = 0; | |
663 | m.data = NULL; | |
664 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
665 | m.data, &sz); | |
666 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
667 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
668 | m.size = sz; | |
40c90bca | 669 | if (!(m.data = malloc(m.size))) |
cf0c6164 | 670 | return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); |
40c90bca | 671 | |
1f00591e | 672 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 673 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 674 | m.data, &sz); |
17c76198 PP |
675 | if (rc != GNUTLS_E_SUCCESS) |
676 | { | |
677 | free(m.data); | |
678 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
679 | } | |
1f00591e | 680 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 681 | |
f5d25c2b | 682 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 PP |
683 | { |
684 | free(m.data); | |
685 | return tls_error(US"TLS cache write D-H params failed", | |
cf0c6164 | 686 | strerror(errno), NULL, errstr); |
17c76198 | 687 | } |
b5aea5e1 | 688 | free(m.data); |
f5d25c2b | 689 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
17c76198 | 690 | return tls_error(US"TLS cache write D-H params final newline failed", |
cf0c6164 | 691 | strerror(errno), NULL, errstr); |
17c76198 | 692 | |
f5d25c2b | 693 | if ((rc = close(fd))) |
cf0c6164 | 694 | return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); |
059ec3d9 | 695 | |
17c76198 PP |
696 | if (Urename(temp_fn, filename) < 0) |
697 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
cf0c6164 | 698 | temp_fn, filename), strerror(errno), NULL, errstr); |
059ec3d9 | 699 | |
17c76198 | 700 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
701 | } |
702 | ||
17c76198 | 703 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
704 | return OK; |
705 | } | |
706 | ||
707 | ||
708 | ||
709 | ||
23bb6982 JH |
710 | /* Create and install a selfsigned certificate, for use in server mode */ |
711 | ||
712 | static int | |
cf0c6164 | 713 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
714 | { |
715 | gnutls_x509_crt_t cert = NULL; | |
716 | time_t now; | |
717 | gnutls_x509_privkey_t pkey = NULL; | |
718 | const uschar * where; | |
719 | int rc; | |
720 | ||
721 | where = US"initialising pkey"; | |
722 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
723 | ||
724 | where = US"initialising cert"; | |
725 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
726 | ||
727 | where = US"generating pkey"; | |
728 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 729 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
23bb6982 | 730 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), |
76075bb5 JH |
731 | #else |
732 | 1024, | |
733 | #endif | |
734 | 0))) | |
23bb6982 JH |
735 | goto err; |
736 | ||
737 | where = US"configuring cert"; | |
738 | now = 0; | |
739 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) | |
740 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
741 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
742 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
743 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
744 | ||
745 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
746 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
747 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
748 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
749 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
750 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
751 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
752 | ) | |
753 | goto err; | |
754 | ||
755 | where = US"signing cert"; | |
756 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
757 | ||
758 | where = US"installing selfsign cert"; | |
759 | /* Since: 2.4.0 */ | |
760 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
761 | goto err; | |
762 | ||
763 | rc = OK; | |
764 | ||
765 | out: | |
766 | if (cert) gnutls_x509_crt_deinit(cert); | |
767 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
768 | return rc; | |
769 | ||
770 | err: | |
cf0c6164 | 771 | rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); |
23bb6982 JH |
772 | goto out; |
773 | } | |
774 | ||
775 | ||
776 | ||
777 | ||
059ec3d9 | 778 | /************************************************* |
17c76198 | 779 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
780 | *************************************************/ |
781 | ||
17c76198 PP |
782 | /* Called from both server and client code, via tls_init(), and also from |
783 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
784 | ||
785 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
786 | ||
787 | The callback should not call us unless state->trigger_sni_changes is true, | |
788 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
789 | |
790 | Arguments: | |
17c76198 | 791 | state exim_gnutls_state_st * |
cf0c6164 | 792 | errstr error string pointer |
059ec3d9 PH |
793 | |
794 | Returns: OK/DEFER/FAIL | |
795 | */ | |
796 | ||
797 | static int | |
cf0c6164 | 798 | tls_expand_session_files(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 799 | { |
1365611d | 800 | struct stat statbuf; |
059ec3d9 | 801 | int rc; |
17c76198 PP |
802 | const host_item *host = state->host; /* macro should be reconsidered? */ |
803 | uschar *saved_tls_certificate = NULL; | |
804 | uschar *saved_tls_privatekey = NULL; | |
805 | uschar *saved_tls_verify_certificates = NULL; | |
806 | uschar *saved_tls_crl = NULL; | |
807 | int cert_count; | |
808 | ||
809 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 810 | if (!host) /* server */ |
17c76198 PP |
811 | if (!state->received_sni) |
812 | { | |
d9b2312b JH |
813 | if (state->tls_certificate && |
814 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
815 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
816 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
817 | )) | |
17c76198 PP |
818 | { |
819 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
820 | state->trigger_sni_changes = TRUE; | |
821 | } | |
822 | } | |
823 | else | |
824 | { | |
1365611d | 825 | /* useful for debugging */ |
17c76198 PP |
826 | saved_tls_certificate = state->exp_tls_certificate; |
827 | saved_tls_privatekey = state->exp_tls_privatekey; | |
828 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
829 | saved_tls_crl = state->exp_tls_crl; | |
830 | } | |
059ec3d9 | 831 | |
1365611d PP |
832 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
833 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
834 | ||
17c76198 PP |
835 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
836 | state members, assuming consistent naming; and expand_check() returns | |
837 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 838 | |
17c76198 PP |
839 | /* check if we at least have a certificate, before doing expensive |
840 | D-H generation. */ | |
059ec3d9 | 841 | |
cf0c6164 | 842 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 843 | return DEFER; |
059ec3d9 | 844 | |
17c76198 | 845 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 846 | |
23bb6982 JH |
847 | if ( !state->exp_tls_certificate |
848 | || !*state->exp_tls_certificate | |
849 | ) | |
2b4a568d | 850 | if (!host) |
cf0c6164 | 851 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
852 | else |
853 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 854 | |
cf0c6164 | 855 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
856 | return DEFER; |
857 | ||
17c76198 PP |
858 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
859 | ||
860 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 861 | { |
17c76198 PP |
862 | state->tls_privatekey = state->tls_certificate; |
863 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 864 | } |
c91535f3 | 865 | |
059ec3d9 | 866 | |
17c76198 | 867 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
868 | { |
869 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
870 | state->exp_tls_certificate, state->exp_tls_privatekey); |
871 | ||
872 | if (state->received_sni) | |
23bb6982 JH |
873 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
874 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
875 | ) | |
17c76198 | 876 | { |
b34fc30c | 877 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
878 | } |
879 | else | |
880 | { | |
b34fc30c | 881 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 882 | } |
059ec3d9 | 883 | |
1365611d PP |
884 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
885 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
886 | GNUTLS_X509_FMT_PEM); | |
887 | exim_gnutls_err_check( | |
888 | string_sprintf("cert/key setup: cert=%s key=%s", | |
889 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
890 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 891 | } /* tls_certificate */ |
059ec3d9 | 892 | |
2b4a568d JH |
893 | |
894 | /* Set the OCSP stapling server info */ | |
895 | ||
f2de3a33 | 896 | #ifndef DISABLE_OCSP |
2b4a568d JH |
897 | if ( !host /* server */ |
898 | && tls_ocsp_file | |
899 | ) | |
900 | { | |
9196d5bf JH |
901 | if (gnutls_buggy_ocsp) |
902 | { | |
903 | DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
904 | } | |
905 | else | |
906 | { | |
907 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", | |
cf0c6164 | 908 | &state->exp_tls_ocsp_file, errstr)) |
9196d5bf | 909 | return DEFER; |
2b4a568d | 910 | |
9196d5bf JH |
911 | /* Use the full callback method for stapling just to get observability. |
912 | More efficient would be to read the file once only, if it never changed | |
913 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
44662487 | 914 | |
9196d5bf JH |
915 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, |
916 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 917 | |
9196d5bf JH |
918 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file); |
919 | } | |
2b4a568d JH |
920 | } |
921 | #endif | |
922 | ||
923 | ||
059ec3d9 PH |
924 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
925 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
926 | error message is provided. However, if we just refrain from setting anything up | |
927 | in that case, certificate verification fails, which seems to be the correct | |
928 | behaviour. */ | |
929 | ||
610ff438 | 930 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 931 | { |
cf0c6164 | 932 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 933 | return DEFER; |
610ff438 JH |
934 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
935 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
936 | state->exp_tls_verify_certificates = NULL; | |
937 | #endif | |
17c76198 | 938 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 939 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 940 | return DEFER; |
059ec3d9 | 941 | |
1365611d PP |
942 | if (!(state->exp_tls_verify_certificates && |
943 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
944 | { |
945 | DEBUG(D_tls) | |
1365611d PP |
946 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
947 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 948 | return OK; |
b34fc30c | 949 | } |
1365611d | 950 | } |
83e2f8a2 PP |
951 | else |
952 | { | |
953 | DEBUG(D_tls) | |
954 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
955 | return OK; | |
956 | } | |
17c76198 | 957 | |
cb1d7830 JH |
958 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
959 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
960 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
961 | else | |
962 | #endif | |
1365611d | 963 | { |
cb1d7830 JH |
964 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
965 | { | |
966 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
967 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
968 | strerror(errno)); | |
969 | return DEFER; | |
970 | } | |
17c76198 | 971 | |
a7fec7a7 | 972 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
973 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
974 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
975 | other weirdness. The thing we really want to check is that it's not a | |
976 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 977 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
978 | if (S_ISDIR(statbuf.st_mode)) |
979 | { | |
980 | DEBUG(D_tls) | |
981 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
982 | state->exp_tls_verify_certificates); | |
983 | log_write(0, LOG_MAIN|LOG_PANIC, | |
984 | "tls_verify_certificates \"%s\" is a directory", | |
985 | state->exp_tls_verify_certificates); | |
986 | return DEFER; | |
987 | } | |
a7fec7a7 | 988 | #endif |
059ec3d9 | 989 | |
cb1d7830 JH |
990 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
991 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 992 | |
cb1d7830 JH |
993 | if (statbuf.st_size == 0) |
994 | { | |
995 | DEBUG(D_tls) | |
996 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
997 | return OK; | |
998 | } | |
059ec3d9 | 999 | |
cb1d7830 | 1000 | cert_count = |
a7fec7a7 JH |
1001 | |
1002 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1003 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1004 | ? | |
1005 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1006 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1007 | : | |
a7fec7a7 | 1008 | #endif |
cb1d7830 JH |
1009 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1010 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1011 | } | |
a7fec7a7 | 1012 | |
1365611d PP |
1013 | if (cert_count < 0) |
1014 | { | |
1015 | rc = cert_count; | |
cb1d7830 | 1016 | exim_gnutls_err_check(US"setting certificate trust"); |
1365611d PP |
1017 | } |
1018 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1019 | |
5c8cda3a PP |
1020 | if (state->tls_crl && *state->tls_crl && |
1021 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1022 | { |
5c8cda3a PP |
1023 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1024 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1025 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1026 | if (cert_count < 0) | |
1365611d | 1027 | { |
5c8cda3a | 1028 | rc = cert_count; |
1365611d PP |
1029 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
1030 | } | |
5c8cda3a | 1031 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1032 | } |
059ec3d9 | 1033 | |
059ec3d9 PH |
1034 | return OK; |
1035 | } | |
1036 | ||
1037 | ||
1038 | ||
1039 | ||
1365611d PP |
1040 | /************************************************* |
1041 | * Set X.509 state variables * | |
1042 | *************************************************/ | |
1043 | ||
1044 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1045 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1046 | structure. Which means various other non-re-expanded pieces of state | |
1047 | need to be re-set in the new struct, so the setting logic is pulled | |
1048 | out to this. | |
1049 | ||
1050 | Arguments: | |
1051 | state exim_gnutls_state_st * | |
cf0c6164 | 1052 | errstr error string pointer |
1365611d PP |
1053 | |
1054 | Returns: OK/DEFER/FAIL | |
1055 | */ | |
1056 | ||
1057 | static int | |
cf0c6164 | 1058 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1059 | { |
1060 | int rc; | |
1061 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1062 | ||
1063 | /* Create D-H parameters, or read them from the cache file. This function does | |
1064 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1065 | client-side params. */ | |
1066 | ||
1067 | if (!state->host) | |
1068 | { | |
1069 | if (!dh_server_params) | |
1070 | { | |
cf0c6164 | 1071 | rc = init_server_dh(errstr); |
1365611d PP |
1072 | if (rc != OK) return rc; |
1073 | } | |
1074 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1075 | } | |
1076 | ||
1077 | /* Link the credentials to the session. */ | |
1078 | ||
1079 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
1080 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
1081 | ||
1082 | return OK; | |
1083 | } | |
1084 | ||
059ec3d9 | 1085 | /************************************************* |
17c76198 | 1086 | * Initialize for GnuTLS * |
059ec3d9 PH |
1087 | *************************************************/ |
1088 | ||
9196d5bf | 1089 | |
4fb7df6d JH |
1090 | #ifndef DISABLE_OCSP |
1091 | ||
9196d5bf JH |
1092 | static BOOL |
1093 | tls_is_buggy_ocsp(void) | |
1094 | { | |
1095 | const uschar * s; | |
1096 | uschar maj, mid, mic; | |
1097 | ||
1098 | s = CUS gnutls_check_version(NULL); | |
1099 | maj = atoi(CCS s); | |
1100 | if (maj == 3) | |
1101 | { | |
1102 | while (*s && *s != '.') s++; | |
1103 | mid = atoi(CCS ++s); | |
1104 | if (mid <= 2) | |
1105 | return TRUE; | |
1106 | else if (mid >= 5) | |
1107 | return FALSE; | |
1108 | else | |
1109 | { | |
1110 | while (*s && *s != '.') s++; | |
1111 | mic = atoi(CCS ++s); | |
1112 | return mic <= (mid == 3 ? 16 : 3); | |
1113 | } | |
1114 | } | |
1115 | return FALSE; | |
1116 | } | |
1117 | ||
4fb7df6d | 1118 | #endif |
9196d5bf JH |
1119 | |
1120 | ||
17c76198 PP |
1121 | /* Called from both server and client code. In the case of a server, errors |
1122 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1123 | |
1124 | Arguments: | |
17c76198 PP |
1125 | host connected host, if client; NULL if server |
1126 | certificate certificate file | |
1127 | privatekey private key file | |
1128 | sni TLS SNI to send, sometimes when client; else NULL | |
1129 | cas CA certs file | |
1130 | crl CRL file | |
1131 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1132 | caller_state returned state-info structure |
cf0c6164 | 1133 | errstr error string pointer |
059ec3d9 | 1134 | |
17c76198 | 1135 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1136 | */ |
1137 | ||
17c76198 PP |
1138 | static int |
1139 | tls_init( | |
1140 | const host_item *host, | |
1141 | const uschar *certificate, | |
1142 | const uschar *privatekey, | |
1143 | const uschar *sni, | |
1144 | const uschar *cas, | |
1145 | const uschar *crl, | |
1146 | const uschar *require_ciphers, | |
cf0c6164 JH |
1147 | exim_gnutls_state_st **caller_state, |
1148 | uschar ** errstr) | |
059ec3d9 | 1149 | { |
17c76198 PP |
1150 | exim_gnutls_state_st *state; |
1151 | int rc; | |
1152 | size_t sz; | |
1153 | const char *errpos; | |
1154 | uschar *p; | |
1155 | BOOL want_default_priorities; | |
1156 | ||
1157 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1158 | { |
17c76198 PP |
1159 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1160 | ||
a5f239e4 PP |
1161 | #ifdef HAVE_GNUTLS_PKCS11 |
1162 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1163 | which loads modules from a config file, which sounds good and may be wanted | |
1164 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1165 | environment variables are used and so breaks for users calling mailq. | |
1166 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1167 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1168 | { |
1169 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1170 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1171 | } | |
1172 | #endif | |
1173 | ||
17c76198 PP |
1174 | rc = gnutls_global_init(); |
1175 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1176 | ||
1177 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1178 | DEBUG(D_tls) | |
059ec3d9 | 1179 | { |
17c76198 PP |
1180 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1181 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1182 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1183 | } |
17c76198 PP |
1184 | #endif |
1185 | ||
4fb7df6d JH |
1186 | #ifndef DISABLE_OCSP |
1187 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1188 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1189 | #endif |
9196d5bf | 1190 | |
17c76198 | 1191 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1192 | } |
059ec3d9 | 1193 | |
17c76198 PP |
1194 | if (host) |
1195 | { | |
1196 | state = &state_client; | |
1197 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1198 | state->tlsp = &tls_out; |
17c76198 PP |
1199 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1200 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1201 | } | |
1202 | else | |
1203 | { | |
1204 | state = &state_server; | |
1205 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1206 | state->tlsp = &tls_in; |
17c76198 PP |
1207 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1208 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1209 | } | |
1210 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1211 | |
17c76198 | 1212 | state->host = host; |
059ec3d9 | 1213 | |
17c76198 PP |
1214 | state->tls_certificate = certificate; |
1215 | state->tls_privatekey = privatekey; | |
5779e6aa | 1216 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1217 | state->tls_sni = sni; |
1218 | state->tls_verify_certificates = cas; | |
1219 | state->tls_crl = crl; | |
059ec3d9 | 1220 | |
17c76198 PP |
1221 | /* This handles the variables that might get re-expanded after TLS SNI; |
1222 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1223 | |
17c76198 PP |
1224 | DEBUG(D_tls) |
1225 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1226 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1227 | |
1365611d PP |
1228 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1229 | requires a new structure afterwards. */ | |
83da1223 | 1230 | |
cf0c6164 | 1231 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1232 | |
17c76198 PP |
1233 | /* set SNI in client, only */ |
1234 | if (host) | |
1235 | { | |
cf0c6164 | 1236 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1237 | return DEFER; |
0df4ab80 | 1238 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1239 | { |
1240 | DEBUG(D_tls) | |
0df4ab80 JH |
1241 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1242 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1243 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1244 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
17c76198 PP |
1245 | exim_gnutls_err_check(US"gnutls_server_name_set"); |
1246 | } | |
1247 | } | |
1248 | else if (state->tls_sni) | |
1249 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1250 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1251 | |
17c76198 | 1252 | /* This is the priority string support, |
42bfef1e | 1253 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1254 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1255 | This was backwards incompatible, but means Exim no longer needs to track | |
1256 | all algorithms and provide string forms for them. */ | |
83da1223 | 1257 | |
17c76198 | 1258 | want_default_priorities = TRUE; |
83da1223 | 1259 | |
17c76198 | 1260 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1261 | { |
cf0c6164 | 1262 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1263 | return DEFER; |
1264 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1265 | { |
17c76198 PP |
1266 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1267 | state->exp_tls_require_ciphers); | |
1268 | ||
1269 | rc = gnutls_priority_init(&state->priority_cache, | |
1270 | CS state->exp_tls_require_ciphers, &errpos); | |
1271 | want_default_priorities = FALSE; | |
1272 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1273 | } |
1274 | } | |
17c76198 PP |
1275 | if (want_default_priorities) |
1276 | { | |
83e2f8a2 PP |
1277 | DEBUG(D_tls) |
1278 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1279 | exim_default_gnutls_priority); | |
17c76198 PP |
1280 | rc = gnutls_priority_init(&state->priority_cache, |
1281 | exim_default_gnutls_priority, &errpos); | |
1282 | p = US exim_default_gnutls_priority; | |
1283 | } | |
83da1223 | 1284 | |
17c76198 PP |
1285 | exim_gnutls_err_check(string_sprintf( |
1286 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1287 | p, errpos - CS p, errpos)); | |
1288 | ||
1289 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1290 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1291 | ||
1292 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1293 | ||
1294 | /* Reduce security in favour of increased compatibility, if the admin | |
1295 | decides to make that trade-off. */ | |
1296 | if (gnutls_compat_mode) | |
83da1223 | 1297 | { |
17c76198 PP |
1298 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1299 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1300 | gnutls_session_enable_compatibility_mode(state->session); | |
1301 | #else | |
1302 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1303 | #endif | |
83da1223 PH |
1304 | } |
1305 | ||
17c76198 | 1306 | *caller_state = state; |
17c76198 | 1307 | return OK; |
83da1223 PH |
1308 | } |
1309 | ||
1310 | ||
1311 | ||
059ec3d9 | 1312 | /************************************************* |
17c76198 | 1313 | * Extract peer information * |
059ec3d9 PH |
1314 | *************************************************/ |
1315 | ||
17c76198 | 1316 | /* Called from both server and client code. |
4fe99a6c PP |
1317 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1318 | and we use that to detect double-calls. | |
059ec3d9 | 1319 | |
75fe387d PP |
1320 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1321 | for logging in the server side, but for the client side, we log after teardown | |
1322 | in src/deliver.c. While the session is up, we can twist about states and | |
1323 | repoint tls_* globals, but those variables used for logging or other variable | |
1324 | expansion that happens _after_ delivery need to have a longer life-time. | |
1325 | ||
1326 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1327 | doing this more than once per generation of a state context. We set them in | |
1328 | the state context, and repoint tls_* to them. After the state goes away, the | |
1329 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1330 | ||
1331 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1332 | don't apply. | |
1333 | ||
059ec3d9 | 1334 | Arguments: |
17c76198 | 1335 | state exim_gnutls_state_st * |
cf0c6164 | 1336 | errstr pointer to error string |
059ec3d9 | 1337 | |
17c76198 | 1338 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1339 | */ |
1340 | ||
17c76198 | 1341 | static int |
cf0c6164 | 1342 | peer_status(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 1343 | { |
75fe387d | 1344 | uschar cipherbuf[256]; |
27f19eb4 | 1345 | const gnutls_datum_t *cert_list; |
75fe387d | 1346 | int old_pool, rc; |
17c76198 | 1347 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1348 | gnutls_protocol_t protocol; |
1349 | gnutls_cipher_algorithm_t cipher; | |
1350 | gnutls_kx_algorithm_t kx; | |
1351 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1352 | gnutls_certificate_type_t ct; |
1353 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1354 | uschar *p, *dn_buf; |
17c76198 | 1355 | size_t sz; |
059ec3d9 | 1356 | |
4fe99a6c | 1357 | if (state->have_set_peerdn) |
17c76198 | 1358 | return OK; |
4fe99a6c | 1359 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1360 | |
4fe99a6c | 1361 | state->peerdn = NULL; |
059ec3d9 | 1362 | |
4fe99a6c PP |
1363 | /* tls_cipher */ |
1364 | cipher = gnutls_cipher_get(state->session); | |
1365 | protocol = gnutls_protocol_get_version(state->session); | |
1366 | mac = gnutls_mac_get(state->session); | |
1367 | kx = gnutls_kx_get(state->session); | |
1368 | ||
75fe387d | 1369 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1370 | "%s:%s:%d", |
1371 | gnutls_protocol_get_name(protocol), | |
1372 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1373 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1374 | ||
1375 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1376 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1377 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1378 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1379 | if (isspace(*p)) |
1380 | *p = '-'; | |
75fe387d PP |
1381 | old_pool = store_pool; |
1382 | store_pool = POOL_PERM; | |
1383 | state->ciphersuite = string_copy(cipherbuf); | |
1384 | store_pool = old_pool; | |
817d9f57 | 1385 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1386 | |
1387 | /* tls_peerdn */ | |
17c76198 | 1388 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1389 | |
17c76198 PP |
1390 | if (cert_list == NULL || cert_list_size == 0) |
1391 | { | |
17c76198 PP |
1392 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1393 | cert_list, cert_list_size); | |
e51c7be2 | 1394 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1395 | return tls_error(US"certificate verification failed", |
cf0c6164 | 1396 | "no certificate received from peer", state->host, errstr); |
17c76198 PP |
1397 | return OK; |
1398 | } | |
059ec3d9 | 1399 | |
17c76198 PP |
1400 | ct = gnutls_certificate_type_get(state->session); |
1401 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1402 | { |
17c76198 | 1403 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1404 | DEBUG(D_tls) |
1405 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1406 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1407 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1408 | ctn, state->host, errstr); |
17c76198 | 1409 | return OK; |
83da1223 | 1410 | } |
059ec3d9 | 1411 | |
e51c7be2 JH |
1412 | #define exim_gnutls_peer_err(Label) \ |
1413 | do { \ | |
1414 | if (rc != GNUTLS_E_SUCCESS) \ | |
1415 | { \ | |
1416 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1417 | (Label), gnutls_strerror(rc)); \ | |
1418 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
cf0c6164 | 1419 | return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ |
e51c7be2 JH |
1420 | return OK; \ |
1421 | } \ | |
1422 | } while (0) | |
17c76198 | 1423 | |
9d1c15ef JH |
1424 | rc = import_cert(&cert_list[0], &crt); |
1425 | exim_gnutls_peer_err(US"cert 0"); | |
1426 | ||
1427 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1428 | |
17c76198 PP |
1429 | sz = 0; |
1430 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1431 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1432 | { |
17c76198 PP |
1433 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1434 | return FAIL; /* should not happen */ | |
059ec3d9 | 1435 | } |
17c76198 PP |
1436 | dn_buf = store_get_perm(sz); |
1437 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1438 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1439 | |
17c76198 PP |
1440 | state->peerdn = dn_buf; |
1441 | ||
1442 | return OK; | |
1443 | #undef exim_gnutls_peer_err | |
1444 | } | |
059ec3d9 | 1445 | |
059ec3d9 | 1446 | |
059ec3d9 | 1447 | |
059ec3d9 | 1448 | |
17c76198 PP |
1449 | /************************************************* |
1450 | * Verify peer certificate * | |
1451 | *************************************************/ | |
059ec3d9 | 1452 | |
17c76198 PP |
1453 | /* Called from both server and client code. |
1454 | *Should* be using a callback registered with | |
1455 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1456 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1457 | |
17c76198 PP |
1458 | Arguments: |
1459 | state exim_gnutls_state_st * | |
cf0c6164 | 1460 | errstr where to put an error message |
059ec3d9 | 1461 | |
17c76198 PP |
1462 | Returns: |
1463 | FALSE if the session should be rejected | |
1464 | TRUE if the cert is okay or we just don't care | |
1465 | */ | |
059ec3d9 | 1466 | |
17c76198 | 1467 | static BOOL |
cf0c6164 | 1468 | verify_certificate(exim_gnutls_state_st *state, uschar ** errstr) |
17c76198 PP |
1469 | { |
1470 | int rc; | |
1471 | unsigned int verify; | |
1472 | ||
cf0c6164 | 1473 | *errstr = NULL; |
17c76198 | 1474 | |
cf0c6164 | 1475 | if ((rc = peer_status(state, errstr)) != OK) |
e6060e2c | 1476 | { |
17c76198 | 1477 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1478 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1479 | } |
1480 | else | |
17c76198 | 1481 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1482 | |
17c76198 PP |
1483 | /* Handle the result of verification. INVALID seems to be set as well |
1484 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1485 | |
e51c7be2 JH |
1486 | if (rc < 0 || |
1487 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1488 | ) | |
17c76198 PP |
1489 | { |
1490 | state->peer_cert_verified = FALSE; | |
cf0c6164 JH |
1491 | if (!*errstr) |
1492 | *errstr = verify & GNUTLS_CERT_REVOKED | |
1493 | ? US"certificate revoked" : US"certificate invalid"; | |
059ec3d9 | 1494 | |
17c76198 | 1495 | DEBUG(D_tls) |
e51c7be2 | 1496 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1497 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1498 | |
e51c7be2 | 1499 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1500 | { |
e51c7be2 JH |
1501 | gnutls_alert_send(state->session, |
1502 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1503 | return FALSE; |
1504 | } | |
1505 | DEBUG(D_tls) | |
4789da3a | 1506 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1507 | } |
e51c7be2 | 1508 | |
17c76198 PP |
1509 | else |
1510 | { | |
aa2a70ba | 1511 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1512 | { |
1513 | int sep = 0; | |
55414b25 | 1514 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 | 1515 | uschar * name; |
76075bb5 | 1516 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) |
e51c7be2 JH |
1517 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) |
1518 | break; | |
1519 | if (!name) | |
1520 | { | |
1521 | DEBUG(D_tls) | |
1522 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba JH |
1523 | if (state->verify_requirement >= VERIFY_REQUIRED) |
1524 | { | |
1525 | gnutls_alert_send(state->session, | |
1526 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1527 | return FALSE; | |
1528 | } | |
1529 | return TRUE; | |
e51c7be2 JH |
1530 | } |
1531 | } | |
17c76198 | 1532 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1533 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1534 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1535 | } |
059ec3d9 | 1536 | |
817d9f57 | 1537 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1538 | |
17c76198 PP |
1539 | return TRUE; |
1540 | } | |
059ec3d9 | 1541 | |
17c76198 PP |
1542 | |
1543 | ||
1544 | ||
1545 | /* ------------------------------------------------------------------------ */ | |
1546 | /* Callbacks */ | |
1547 | ||
1548 | /* Logging function which can be registered with | |
1549 | * gnutls_global_set_log_function() | |
1550 | * gnutls_global_set_log_level() 0..9 | |
1551 | */ | |
af3498d6 | 1552 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1553 | static void |
17c76198 | 1554 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1555 | { |
8c79eebf PP |
1556 | size_t len = strlen(message); |
1557 | if (len < 1) | |
1558 | { | |
1559 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1560 | return; | |
1561 | } | |
1562 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1563 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1564 | } |
af3498d6 | 1565 | #endif |
059ec3d9 | 1566 | |
059ec3d9 | 1567 | |
17c76198 PP |
1568 | /* Called after client hello, should handle SNI work. |
1569 | This will always set tls_sni (state->received_sni) if available, | |
1570 | and may trigger presenting different certificates, | |
1571 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1572 | |
17c76198 PP |
1573 | Should be registered with |
1574 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1575 | |
17c76198 PP |
1576 | "This callback must return 0 on success or a gnutls error code to terminate the |
1577 | handshake.". | |
059ec3d9 | 1578 | |
17c76198 PP |
1579 | For inability to get SNI information, we return 0. |
1580 | We only return non-zero if re-setup failed. | |
817d9f57 | 1581 | Only used for server-side TLS. |
17c76198 | 1582 | */ |
44bbabb5 | 1583 | |
17c76198 PP |
1584 | static int |
1585 | exim_sni_handling_cb(gnutls_session_t session) | |
1586 | { | |
1587 | char sni_name[MAX_HOST_LEN]; | |
1588 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1589 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1590 | unsigned int sni_type; |
1591 | int rc, old_pool; | |
cf0c6164 | 1592 | uschar * dummy_errstr; |
17c76198 PP |
1593 | |
1594 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1595 | if (rc != GNUTLS_E_SUCCESS) |
1596 | { | |
1597 | DEBUG(D_tls) { | |
1598 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1599 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1600 | else | |
1601 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1602 | gnutls_strerror(rc), rc); | |
cf0c6164 | 1603 | } |
b34fc30c PP |
1604 | return 0; |
1605 | } | |
1606 | ||
17c76198 PP |
1607 | if (sni_type != GNUTLS_NAME_DNS) |
1608 | { | |
1609 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1610 | return 0; | |
1611 | } | |
44bbabb5 | 1612 | |
17c76198 PP |
1613 | /* We now have a UTF-8 string in sni_name */ |
1614 | old_pool = store_pool; | |
1615 | store_pool = POOL_PERM; | |
1616 | state->received_sni = string_copyn(US sni_name, data_len); | |
1617 | store_pool = old_pool; | |
1618 | ||
1619 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1620 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1621 | |
1622 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1623 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1624 | ||
1625 | if (!state->trigger_sni_changes) | |
1626 | return 0; | |
1627 | ||
cf0c6164 | 1628 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
1629 | { |
1630 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1631 | been offered. The best we can do now is abort. */ | |
1632 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1633 | } | |
1634 | ||
cf0c6164 | 1635 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
1636 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
1637 | ||
1638 | return 0; | |
059ec3d9 PH |
1639 | } |
1640 | ||
1641 | ||
1642 | ||
f2de3a33 | 1643 | #ifndef DISABLE_OCSP |
44662487 JH |
1644 | |
1645 | static int | |
1646 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1647 | gnutls_datum_t * ocsp_response) | |
1648 | { | |
1649 | int ret; | |
1650 | ||
44662487 JH |
1651 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1652 | { | |
1653 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
1654 | (char *)ptr); | |
018058b2 | 1655 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1656 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1657 | } | |
1658 | ||
018058b2 | 1659 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1660 | return 0; |
1661 | } | |
1662 | ||
1663 | #endif | |
1664 | ||
1665 | ||
0cbf2b82 | 1666 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1667 | /* |
1668 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1669 | for an exim TLS connection (either direction), raising a tls:cert event |
1670 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1671 | can deny verification. |
1672 | ||
1673 | Return 0 for the handshake to continue or non-zero to terminate. | |
1674 | */ | |
1675 | ||
1676 | static int | |
723fe533 | 1677 | verify_cb(gnutls_session_t session) |
a7538db1 | 1678 | { |
27f19eb4 | 1679 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1680 | unsigned int cert_list_size = 0; |
1681 | gnutls_x509_crt_t crt; | |
1682 | int rc; | |
b30275b8 | 1683 | uschar * yield; |
a7538db1 JH |
1684 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1685 | ||
1686 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1687 | if (cert_list) | |
1688 | while (cert_list_size--) | |
1689 | { | |
1690 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1691 | if (rc != GNUTLS_E_SUCCESS) | |
1692 | { | |
1693 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1694 | cert_list_size, gnutls_strerror(rc)); | |
1695 | break; | |
1696 | } | |
1697 | ||
1698 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1699 | if ((yield = event_raise(state->event_action, |
1700 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1701 | { |
1702 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1703 | "SSL verify denied by event-action: depth=%d: %s", |
1704 | cert_list_size, yield); | |
a7538db1 JH |
1705 | return 1; /* reject */ |
1706 | } | |
1707 | state->tlsp->peercert = NULL; | |
1708 | } | |
1709 | ||
1710 | return 0; | |
1711 | } | |
1712 | ||
1713 | #endif | |
44662487 JH |
1714 | |
1715 | ||
17c76198 PP |
1716 | |
1717 | /* ------------------------------------------------------------------------ */ | |
1718 | /* Exported functions */ | |
1719 | ||
1720 | ||
1721 | ||
1722 | ||
059ec3d9 PH |
1723 | /************************************************* |
1724 | * Start a TLS session in a server * | |
1725 | *************************************************/ | |
1726 | ||
1727 | /* This is called when Exim is running as a server, after having received | |
1728 | the STARTTLS command. It must respond to that command, and then negotiate | |
1729 | a TLS session. | |
1730 | ||
1731 | Arguments: | |
83da1223 | 1732 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 1733 | errstr pointer to error string |
059ec3d9 PH |
1734 | |
1735 | Returns: OK on success | |
1736 | DEFER for errors before the start of the negotiation | |
4c04137d | 1737 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
1738 | continue running. |
1739 | */ | |
1740 | ||
1741 | int | |
cf0c6164 | 1742 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
1743 | { |
1744 | int rc; | |
cf0c6164 | 1745 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
1746 | |
1747 | /* Check for previous activation */ | |
817d9f57 | 1748 | if (tls_in.active >= 0) |
059ec3d9 | 1749 | { |
cf0c6164 | 1750 | tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); |
925ac8e4 | 1751 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
1752 | return FAIL; |
1753 | } | |
1754 | ||
1755 | /* Initialize the library. If it fails, it will already have logged the error | |
1756 | and sent an SMTP response. */ | |
1757 | ||
17c76198 | 1758 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1759 | |
cf0c6164 | 1760 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 1761 | NULL, tls_verify_certificates, tls_crl, |
cf0c6164 | 1762 | require_ciphers, &state, errstr)) != OK) return rc; |
059ec3d9 | 1763 | |
059ec3d9 PH |
1764 | /* If this is a host for which certificate verification is mandatory or |
1765 | optional, set up appropriately. */ | |
1766 | ||
059ec3d9 | 1767 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1768 | { |
e51c7be2 JH |
1769 | DEBUG(D_tls) |
1770 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1771 | state->verify_requirement = VERIFY_REQUIRED; |
1772 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1773 | } | |
059ec3d9 | 1774 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1775 | { |
e51c7be2 JH |
1776 | DEBUG(D_tls) |
1777 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1778 | state->verify_requirement = VERIFY_OPTIONAL; |
1779 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1780 | } | |
1781 | else | |
1782 | { | |
e51c7be2 JH |
1783 | DEBUG(D_tls) |
1784 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1785 | state->verify_requirement = VERIFY_NONE; |
1786 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1787 | } | |
059ec3d9 | 1788 | |
0cbf2b82 | 1789 | #ifndef DISABLE_EVENT |
723fe533 JH |
1790 | if (event_action) |
1791 | { | |
1792 | state->event_action = event_action; | |
1793 | gnutls_session_set_ptr(state->session, state); | |
1794 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
1795 | } | |
1796 | #endif | |
1797 | ||
17c76198 PP |
1798 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1799 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1800 | |
17c76198 PP |
1801 | gnutls_handshake_set_post_client_hello_function(state->session, |
1802 | exim_sni_handling_cb); | |
059ec3d9 PH |
1803 | |
1804 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1805 | on connection, where outputting anything now upsets the clients and tends to | |
1806 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1807 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1808 | mode, the fflush() happens when smtp_getc() is called. */ | |
1809 | ||
817d9f57 | 1810 | if (!state->tlsp->on_connect) |
059ec3d9 | 1811 | { |
925ac8e4 | 1812 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 1813 | fflush(smtp_out); |
059ec3d9 PH |
1814 | } |
1815 | ||
1816 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1817 | that the GnuTLS library doesn't. */ | |
1818 | ||
17c76198 | 1819 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
1820 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
1821 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
1822 | state->fd_in = fileno(smtp_in); |
1823 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1824 | |
1825 | sigalrm_seen = FALSE; | |
1826 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1827 | do |
17c76198 | 1828 | rc = gnutls_handshake(state->session); |
157a7880 | 1829 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
1830 | alarm(0); |
1831 | ||
17c76198 | 1832 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1833 | { |
059ec3d9 PH |
1834 | /* It seems that, except in the case of a timeout, we have to close the |
1835 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1836 | until the server times out. */ | |
1837 | ||
60d10ce7 | 1838 | if (sigalrm_seen) |
ad7fc6eb | 1839 | { |
cf0c6164 | 1840 | tls_error(US"gnutls_handshake", "timed out", NULL, errstr); |
ad7fc6eb JH |
1841 | gnutls_db_remove_session(state->session); |
1842 | } | |
60d10ce7 | 1843 | else |
059ec3d9 | 1844 | { |
cf0c6164 | 1845 | tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); |
f5d25c2b | 1846 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 1847 | gnutls_deinit(state->session); |
ed62aae3 | 1848 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 1849 | millisleep(500); |
ad7fc6eb | 1850 | shutdown(state->fd_out, SHUT_WR); |
60d10ce7 | 1851 | for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ |
f1e894f3 PH |
1852 | (void)fclose(smtp_out); |
1853 | (void)fclose(smtp_in); | |
60d10ce7 | 1854 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
1855 | } |
1856 | ||
1857 | return FAIL; | |
1858 | } | |
1859 | ||
1860 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1861 | ||
17c76198 PP |
1862 | /* Verify after the fact */ |
1863 | ||
9d1c15ef | 1864 | if ( state->verify_requirement != VERIFY_NONE |
cf0c6164 | 1865 | && !verify_certificate(state, errstr)) |
059ec3d9 | 1866 | { |
9d1c15ef | 1867 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1868 | { |
cf0c6164 | 1869 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 1870 | return FAIL; |
17c76198 | 1871 | } |
9d1c15ef JH |
1872 | DEBUG(D_tls) |
1873 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 1874 | *errstr); |
059ec3d9 PH |
1875 | } |
1876 | ||
17c76198 PP |
1877 | /* Figure out peer DN, and if authenticated, etc. */ |
1878 | ||
cf0c6164 | 1879 | if ((rc = peer_status(state, NULL)) != OK) return rc; |
17c76198 PP |
1880 | |
1881 | /* Sets various Exim expansion variables; always safe within server */ | |
1882 | ||
9d1c15ef | 1883 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1884 | |
1885 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1886 | and initialize appropriately. */ | |
1887 | ||
17c76198 | 1888 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1889 | |
1890 | receive_getc = tls_getc; | |
0d81dabc | 1891 | receive_getbuf = tls_getbuf; |
584e96c6 | 1892 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
1893 | receive_ungetc = tls_ungetc; |
1894 | receive_feof = tls_feof; | |
1895 | receive_ferror = tls_ferror; | |
58eb016e | 1896 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1897 | |
059ec3d9 PH |
1898 | return OK; |
1899 | } | |
1900 | ||
1901 | ||
1902 | ||
1903 | ||
aa2a70ba JH |
1904 | static void |
1905 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
1906 | smtp_transport_options_block * ob) | |
1907 | { | |
5130845b | 1908 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 1909 | { |
4af0d74a | 1910 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 1911 | #ifdef SUPPORT_I18N |
4af0d74a JH |
1912 | string_domain_utf8_to_alabel(host->name, NULL); |
1913 | #else | |
1914 | host->name; | |
1915 | #endif | |
aa2a70ba JH |
1916 | DEBUG(D_tls) |
1917 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
1918 | state->exp_tls_verify_cert_hostnames); | |
1919 | } | |
1920 | } | |
aa2a70ba JH |
1921 | |
1922 | ||
059ec3d9 PH |
1923 | /************************************************* |
1924 | * Start a TLS session in a client * | |
1925 | *************************************************/ | |
1926 | ||
1927 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1928 | ||
1929 | Arguments: | |
1930 | fd the fd of the connection | |
1931 | host connected host (for messages) | |
83da1223 | 1932 | addr the first address (not used) |
a7538db1 | 1933 | tb transport (always smtp) |
059ec3d9 | 1934 | |
cf0c6164 JH |
1935 | errstr error string pointer |
1936 | ||
059ec3d9 PH |
1937 | Returns: OK/DEFER/FAIL (because using common functions), |
1938 | but for a client, DEFER and FAIL have the same meaning | |
1939 | */ | |
1940 | ||
1941 | int | |
17c76198 | 1942 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1943 | address_item *addr ARG_UNUSED, |
cf0c6164 | 1944 | transport_instance * tb, |
0e66b3b6 | 1945 | #ifdef EXPERIMENTAL_DANE |
cf0c6164 | 1946 | dns_answer * tlsa_dnsa ARG_UNUSED, |
0e66b3b6 | 1947 | #endif |
cf0c6164 | 1948 | uschar ** errstr) |
059ec3d9 | 1949 | { |
a7538db1 JH |
1950 | smtp_transport_options_block *ob = |
1951 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 1952 | int rc; |
17c76198 | 1953 | exim_gnutls_state_st *state = NULL; |
f2de3a33 | 1954 | #ifndef DISABLE_OCSP |
5130845b JH |
1955 | BOOL require_ocsp = |
1956 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 1957 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 1958 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 1959 | #endif |
059ec3d9 | 1960 | |
17c76198 | 1961 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1962 | |
65867078 JH |
1963 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
1964 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
cf0c6164 | 1965 | ob->tls_require_ciphers, &state, errstr)) != OK) |
2b4a568d | 1966 | return rc; |
059ec3d9 | 1967 | |
54c90be1 | 1968 | { |
65867078 JH |
1969 | int dh_min_bits = ob->tls_dh_min_bits; |
1970 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
1971 | { | |
1972 | DEBUG(D_tls) | |
1973 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
1974 | " clamping %d up to %d\n", | |
1975 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1976 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1977 | } | |
54c90be1 | 1978 | |
65867078 JH |
1979 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
1980 | " acceptable bits to %d\n", | |
1981 | dh_min_bits); | |
1982 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
1983 | } | |
83da1223 | 1984 | |
94431adb | 1985 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
1986 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
1987 | the specified host patterns if one of them is defined */ | |
1988 | ||
aa2a70ba JH |
1989 | if ( ( state->exp_tls_verify_certificates |
1990 | && !ob->tls_verify_hosts | |
610ff438 | 1991 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) |
aa2a70ba | 1992 | ) |
5130845b | 1993 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK |
2b4a568d | 1994 | ) |
17c76198 | 1995 | { |
aa2a70ba | 1996 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
1997 | DEBUG(D_tls) |
1998 | debug_printf("TLS: server certificate verification required.\n"); | |
1999 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2000 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2001 | } | |
5130845b | 2002 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2003 | { |
aa2a70ba | 2004 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2005 | DEBUG(D_tls) |
2006 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2007 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2008 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2009 | } | |
2010 | else | |
2011 | { | |
e51c7be2 JH |
2012 | DEBUG(D_tls) |
2013 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2014 | state->verify_requirement = VERIFY_NONE; |
2015 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2016 | } |
059ec3d9 | 2017 | |
f2de3a33 JH |
2018 | #ifndef DISABLE_OCSP |
2019 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2020 | if (request_ocsp) |
9d1c15ef JH |
2021 | { |
2022 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2023 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2024 | NULL, 0, NULL)) != OK) | |
9d1c15ef | 2025 | return tls_error(US"cert-status-req", |
cf0c6164 | 2026 | gnutls_strerror(rc), state->host, errstr); |
44662487 | 2027 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2028 | } |
2b4a568d JH |
2029 | #endif |
2030 | ||
0cbf2b82 | 2031 | #ifndef DISABLE_EVENT |
774ef2d7 | 2032 | if (tb->event_action) |
a7538db1 | 2033 | { |
774ef2d7 | 2034 | state->event_action = tb->event_action; |
a7538db1 | 2035 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2036 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2037 | } |
2038 | #endif | |
2039 | ||
27f19eb4 | 2040 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2041 | state->fd_in = fd; |
2042 | state->fd_out = fd; | |
059ec3d9 | 2043 | |
9d1c15ef | 2044 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2045 | /* There doesn't seem to be a built-in timeout on connection. */ |
2046 | ||
2047 | sigalrm_seen = FALSE; | |
65867078 | 2048 | alarm(ob->command_timeout); |
17c76198 PP |
2049 | do |
2050 | { | |
2051 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
2052 | } while ((rc == GNUTLS_E_AGAIN) || |
2053 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
2054 | alarm(0); |
2055 | ||
4fe99a6c | 2056 | if (rc != GNUTLS_E_SUCCESS) |
60d10ce7 JH |
2057 | if (sigalrm_seen) |
2058 | { | |
2059 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
cf0c6164 | 2060 | return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); |
60d10ce7 JH |
2061 | } |
2062 | else | |
cf0c6164 | 2063 | return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); |
4fe99a6c | 2064 | |
17c76198 | 2065 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2066 | |
17c76198 | 2067 | /* Verify late */ |
059ec3d9 | 2068 | |
17c76198 | 2069 | if (state->verify_requirement != VERIFY_NONE && |
cf0c6164 JH |
2070 | !verify_certificate(state, errstr)) |
2071 | return tls_error(US"certificate verification failed", *errstr, state->host, errstr); | |
059ec3d9 | 2072 | |
f2de3a33 | 2073 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2074 | if (require_ocsp) |
2075 | { | |
2076 | DEBUG(D_tls) | |
2077 | { | |
2078 | gnutls_datum_t stapling; | |
2079 | gnutls_ocsp_resp_t resp; | |
2080 | gnutls_datum_t printed; | |
2081 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2082 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2083 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2084 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2085 | ) | |
2086 | { | |
65867078 | 2087 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2088 | gnutls_free(printed.data); |
2089 | } | |
2090 | else | |
cf0c6164 | 2091 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host, errstr); |
2b4a568d JH |
2092 | } |
2093 | ||
2b4a568d | 2094 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2095 | { |
2096 | tls_out.ocsp = OCSP_FAILED; | |
cf0c6164 | 2097 | return tls_error(US"certificate status check failed", NULL, state->host, errstr); |
018058b2 | 2098 | } |
2b4a568d | 2099 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2100 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2101 | } |
2102 | #endif | |
2103 | ||
17c76198 | 2104 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2105 | |
cf0c6164 | 2106 | if ((rc = peer_status(state, errstr)) != OK) |
2b4a568d | 2107 | return rc; |
059ec3d9 | 2108 | |
4fe99a6c | 2109 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2110 | |
9d1c15ef | 2111 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2112 | |
059ec3d9 PH |
2113 | return OK; |
2114 | } | |
2115 | ||
2116 | ||
2117 | ||
17c76198 | 2118 | |
059ec3d9 | 2119 | /************************************************* |
17c76198 | 2120 | * Close down a TLS session * |
059ec3d9 PH |
2121 | *************************************************/ |
2122 | ||
17c76198 PP |
2123 | /* This is also called from within a delivery subprocess forked from the |
2124 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2125 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2126 | |
17c76198 PP |
2127 | Arguments: TRUE if gnutls_bye is to be called |
2128 | Returns: nothing | |
059ec3d9 PH |
2129 | */ |
2130 | ||
17c76198 | 2131 | void |
817d9f57 | 2132 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2133 | { |
817d9f57 | 2134 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2135 | |
389ca47a | 2136 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2137 | |
2138 | if (shutdown) | |
2139 | { | |
f5723109 | 2140 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); |
17c76198 PP |
2141 | gnutls_bye(state->session, GNUTLS_SHUT_WR); |
2142 | } | |
2143 | ||
2144 | gnutls_deinit(state->session); | |
ed62aae3 HSHR |
2145 | gnutls_certificate_free_credentials(state->x509_cred); |
2146 | ||
17c76198 | 2147 | |
389ca47a | 2148 | state->tlsp->active = -1; |
17c76198 PP |
2149 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2150 | ||
2151 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2152 | { | |
2153 | gnutls_global_deinit(); | |
2154 | exim_gnutls_base_init_done = FALSE; | |
2155 | } | |
059ec3d9 PH |
2156 | } |
2157 | ||
2158 | ||
2159 | ||
17c76198 | 2160 | |
0d81dabc JH |
2161 | static BOOL |
2162 | tls_refill(unsigned lim) | |
2163 | { | |
2164 | exim_gnutls_state_st * state = &state_server; | |
2165 | ssize_t inbytes; | |
2166 | ||
2167 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2168 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2169 | ||
2170 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
2171 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2172 | MIN(ssl_xfer_buffer_size, lim)); | |
2173 | alarm(0); | |
2174 | ||
2175 | /* Timeouts do not get this far; see command_timeout_handler(). | |
2176 | A zero-byte return appears to mean that the TLS session has been | |
2177 | closed down, not that the socket itself has been closed down. Revert to | |
2178 | non-TLS handling. */ | |
2179 | ||
2180 | if (sigalrm_seen) | |
2181 | { | |
2182 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
2183 | state->xfer_error = 1; | |
2184 | return FALSE; | |
2185 | } | |
2186 | ||
2187 | else if (inbytes == 0) | |
2188 | { | |
2189 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2190 | ||
2191 | receive_getc = smtp_getc; | |
2192 | receive_getbuf = smtp_getbuf; | |
2193 | receive_get_cache = smtp_get_cache; | |
2194 | receive_ungetc = smtp_ungetc; | |
2195 | receive_feof = smtp_feof; | |
2196 | receive_ferror = smtp_ferror; | |
2197 | receive_smtp_buffered = smtp_buffered; | |
2198 | ||
2199 | gnutls_deinit(state->session); | |
2200 | gnutls_certificate_free_credentials(state->x509_cred); | |
2201 | ||
2202 | state->session = NULL; | |
2203 | state->tlsp->active = -1; | |
2204 | state->tlsp->bits = 0; | |
2205 | state->tlsp->certificate_verified = FALSE; | |
2206 | tls_channelbinding_b64 = NULL; | |
2207 | state->tlsp->cipher = NULL; | |
2208 | state->tlsp->peercert = NULL; | |
2209 | state->tlsp->peerdn = NULL; | |
2210 | ||
2211 | return FALSE; | |
2212 | } | |
2213 | ||
2214 | /* Handle genuine errors */ | |
2215 | ||
2216 | else if (inbytes < 0) | |
2217 | { | |
2218 | record_io_error(state, (int) inbytes, US"recv", NULL); | |
2219 | state->xfer_error = 1; | |
2220 | return FALSE; | |
2221 | } | |
2222 | #ifndef DISABLE_DKIM | |
2223 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
2224 | #endif | |
2225 | state->xfer_buffer_hwm = (int) inbytes; | |
2226 | state->xfer_buffer_lwm = 0; | |
2227 | return TRUE; | |
2228 | } | |
2229 | ||
059ec3d9 PH |
2230 | /************************************************* |
2231 | * TLS version of getc * | |
2232 | *************************************************/ | |
2233 | ||
2234 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2235 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2236 | Only used by the server-side TLS. |
059ec3d9 | 2237 | |
17c76198 PP |
2238 | This feeds DKIM and should be used for all message-body reads. |
2239 | ||
bd8fbe36 | 2240 | Arguments: lim Maximum amount to read/bufffer |
059ec3d9 PH |
2241 | Returns: the next character or EOF |
2242 | */ | |
2243 | ||
2244 | int | |
bd8fbe36 | 2245 | tls_getc(unsigned lim) |
059ec3d9 | 2246 | { |
0d81dabc | 2247 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 2248 | |
0d81dabc JH |
2249 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2250 | if (!tls_refill(lim)) | |
2251 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 2252 | |
0d81dabc | 2253 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2254 | |
0d81dabc JH |
2255 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
2256 | } | |
059ec3d9 | 2257 | |
0d81dabc JH |
2258 | uschar * |
2259 | tls_getbuf(unsigned * len) | |
2260 | { | |
2261 | exim_gnutls_state_st * state = &state_server; | |
2262 | unsigned size; | |
2263 | uschar * buf; | |
059ec3d9 | 2264 | |
0d81dabc JH |
2265 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2266 | if (!tls_refill(*len)) | |
059ec3d9 | 2267 | { |
0d81dabc JH |
2268 | if (!state->xfer_error) return smtp_getbuf(len); |
2269 | *len = 0; | |
2270 | return NULL; | |
059ec3d9 | 2271 | } |
059ec3d9 | 2272 | |
0d81dabc JH |
2273 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
2274 | size = *len; | |
2275 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
2276 | state->xfer_buffer_lwm += size; | |
2277 | *len = size; | |
2278 | return buf; | |
059ec3d9 PH |
2279 | } |
2280 | ||
0d81dabc | 2281 | |
584e96c6 JH |
2282 | void |
2283 | tls_get_cache() | |
2284 | { | |
9960d1e5 | 2285 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2286 | exim_gnutls_state_st * state = &state_server; |
2287 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2288 | if (n > 0) | |
2289 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2290 | #endif |
9960d1e5 | 2291 | } |
584e96c6 | 2292 | |
059ec3d9 | 2293 | |
925ac8e4 JH |
2294 | BOOL |
2295 | tls_could_read(void) | |
2296 | { | |
2297 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
2298 | || gnutls_record_check_pending(state_server.session) > 0; | |
2299 | } | |
2300 | ||
2301 | ||
059ec3d9 | 2302 | |
17c76198 | 2303 | |
059ec3d9 PH |
2304 | /************************************************* |
2305 | * Read bytes from TLS channel * | |
2306 | *************************************************/ | |
2307 | ||
17c76198 PP |
2308 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2309 | then the caller must feed DKIM. | |
817d9f57 | 2310 | |
059ec3d9 PH |
2311 | Arguments: |
2312 | buff buffer of data | |
2313 | len size of buffer | |
2314 | ||
2315 | Returns: the number of bytes read | |
2316 | -1 after a failed read | |
2317 | */ | |
2318 | ||
2319 | int | |
817d9f57 | 2320 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2321 | { |
817d9f57 | 2322 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2323 | ssize_t inbytes; |
059ec3d9 | 2324 | |
17c76198 PP |
2325 | if (len > INT_MAX) |
2326 | len = INT_MAX; | |
059ec3d9 | 2327 | |
17c76198 PP |
2328 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2329 | DEBUG(D_tls) | |
2330 | debug_printf("*** PROBABLY A BUG *** " \ | |
2331 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2332 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2333 | ||
2334 | DEBUG(D_tls) | |
2335 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2336 | state->session, buff, len); | |
2337 | ||
2338 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2339 | if (inbytes > 0) return inbytes; |
2340 | if (inbytes == 0) | |
2341 | { | |
2342 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2343 | } | |
17c76198 | 2344 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2345 | |
2346 | return -1; | |
2347 | } | |
2348 | ||
2349 | ||
2350 | ||
17c76198 | 2351 | |
059ec3d9 PH |
2352 | /************************************************* |
2353 | * Write bytes down TLS channel * | |
2354 | *************************************************/ | |
2355 | ||
2356 | /* | |
2357 | Arguments: | |
817d9f57 | 2358 | is_server channel specifier |
059ec3d9 PH |
2359 | buff buffer of data |
2360 | len number of bytes | |
925ac8e4 | 2361 | more more data expected soon |
059ec3d9 PH |
2362 | |
2363 | Returns: the number of bytes after a successful write, | |
2364 | -1 after a failed write | |
2365 | */ | |
2366 | ||
2367 | int | |
925ac8e4 | 2368 | tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2369 | { |
17c76198 PP |
2370 | ssize_t outbytes; |
2371 | size_t left = len; | |
817d9f57 | 2372 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
925ac8e4 JH |
2373 | #ifdef SUPPORT_CORK |
2374 | static BOOL corked = FALSE; | |
2375 | ||
2376 | if (more && !corked) gnutls_record_cork(state->session); | |
2377 | #endif | |
2378 | ||
2379 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
2380 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 2381 | |
059ec3d9 PH |
2382 | while (left > 0) |
2383 | { | |
17c76198 PP |
2384 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2385 | buff, left); | |
2386 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2387 | |
17c76198 | 2388 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2389 | if (outbytes < 0) |
2390 | { | |
17c76198 | 2391 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2392 | return -1; |
2393 | } | |
2394 | if (outbytes == 0) | |
2395 | { | |
17c76198 | 2396 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2397 | return -1; |
2398 | } | |
2399 | ||
2400 | left -= outbytes; | |
2401 | buff += outbytes; | |
2402 | } | |
2403 | ||
17c76198 PP |
2404 | if (len > INT_MAX) |
2405 | { | |
2406 | DEBUG(D_tls) | |
2407 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2408 | len); | |
2409 | len = INT_MAX; | |
2410 | } | |
2411 | ||
925ac8e4 JH |
2412 | #ifdef SUPPORT_CORK |
2413 | if (more != corked) | |
2414 | { | |
2415 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
2416 | corked = more; | |
2417 | } | |
2418 | #endif | |
2419 | ||
17c76198 | 2420 | return (int) len; |
059ec3d9 PH |
2421 | } |
2422 | ||
2423 | ||
2424 | ||
17c76198 | 2425 | |
059ec3d9 | 2426 | /************************************************* |
17c76198 | 2427 | * Random number generation * |
059ec3d9 PH |
2428 | *************************************************/ |
2429 | ||
17c76198 PP |
2430 | /* Pseudo-random number generation. The result is not expected to be |
2431 | cryptographically strong but not so weak that someone will shoot themselves | |
2432 | in the foot using it as a nonce in input in some email header scheme or | |
2433 | whatever weirdness they'll twist this into. The result should handle fork() | |
2434 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2435 | |
17c76198 PP |
2436 | Arguments: |
2437 | max range maximum | |
2438 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2439 | */ |
2440 | ||
af3498d6 | 2441 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2442 | int |
2443 | vaguely_random_number(int max) | |
059ec3d9 | 2444 | { |
17c76198 PP |
2445 | unsigned int r; |
2446 | int i, needed_len; | |
2447 | uschar *p; | |
2448 | uschar smallbuf[sizeof(r)]; | |
2449 | ||
2450 | if (max <= 1) | |
2451 | return 0; | |
2452 | ||
2453 | needed_len = sizeof(r); | |
2454 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2455 | * asked for a number less than 10. */ | |
2456 | for (r = max, i = 0; r; ++i) | |
2457 | r >>= 1; | |
2458 | i = (i + 7) / 8; | |
2459 | if (i < needed_len) | |
2460 | needed_len = i; | |
2461 | ||
2462 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2463 | if (i < 0) | |
059ec3d9 | 2464 | { |
17c76198 PP |
2465 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2466 | return vaguely_random_number_fallback(max); | |
2467 | } | |
2468 | r = 0; | |
2469 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2470 | { | |
2471 | r *= 256; | |
2472 | r += *p; | |
059ec3d9 PH |
2473 | } |
2474 | ||
17c76198 PP |
2475 | /* We don't particularly care about weighted results; if someone wants |
2476 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2477 | return r % max; | |
059ec3d9 | 2478 | } |
af3498d6 PP |
2479 | #else /* HAVE_GNUTLS_RND */ |
2480 | int | |
2481 | vaguely_random_number(int max) | |
2482 | { | |
2483 | return vaguely_random_number_fallback(max); | |
2484 | } | |
2485 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2486 | |
36f12725 NM |
2487 | |
2488 | ||
2489 | ||
3375e053 PP |
2490 | /************************************************* |
2491 | * Let tls_require_ciphers be checked at startup * | |
2492 | *************************************************/ | |
2493 | ||
2494 | /* The tls_require_ciphers option, if set, must be something which the | |
2495 | library can parse. | |
2496 | ||
2497 | Returns: NULL on success, or error message | |
2498 | */ | |
2499 | ||
2500 | uschar * | |
2501 | tls_validate_require_cipher(void) | |
2502 | { | |
2503 | int rc; | |
2504 | uschar *expciphers = NULL; | |
2505 | gnutls_priority_t priority_cache; | |
2506 | const char *errpos; | |
cf0c6164 | 2507 | uschar * dummy_errstr; |
3375e053 PP |
2508 | |
2509 | #define validate_check_rc(Label) do { \ | |
2510 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2511 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2512 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2513 | ||
2514 | if (exim_gnutls_base_init_done) | |
2515 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2516 | "already initialised GnuTLS, Exim developer bug"); | |
2517 | ||
a5f239e4 | 2518 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2519 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2520 | { |
2521 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2522 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2523 | } | |
2524 | #endif | |
3375e053 PP |
2525 | rc = gnutls_global_init(); |
2526 | validate_check_rc(US"gnutls_global_init()"); | |
2527 | exim_gnutls_base_init_done = TRUE; | |
2528 | ||
2529 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2530 | return_deinit(NULL); | |
2531 | ||
cf0c6164 JH |
2532 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
2533 | &dummy_errstr)) | |
3375e053 PP |
2534 | return_deinit(US"failed to expand tls_require_ciphers"); |
2535 | ||
2536 | if (!(expciphers && *expciphers)) | |
2537 | return_deinit(NULL); | |
2538 | ||
2539 | DEBUG(D_tls) | |
2540 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2541 | ||
2542 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2543 | validate_check_rc(string_sprintf( | |
2544 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2545 | expciphers, errpos - CS expciphers, errpos)); | |
2546 | ||
2547 | #undef return_deinit | |
2548 | #undef validate_check_rc | |
2549 | gnutls_global_deinit(); | |
2550 | ||
2551 | return NULL; | |
2552 | } | |
2553 | ||
2554 | ||
2555 | ||
2556 | ||
36f12725 NM |
2557 | /************************************************* |
2558 | * Report the library versions. * | |
2559 | *************************************************/ | |
2560 | ||
2561 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2562 | ||
2563 | Arguments: a FILE* to print the results to | |
2564 | Returns: nothing | |
2565 | */ | |
2566 | ||
2567 | void | |
2568 | tls_version_report(FILE *f) | |
2569 | { | |
754a0503 PP |
2570 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2571 | " Runtime: %s\n", | |
2572 | LIBGNUTLS_VERSION, | |
2573 | gnutls_check_version(NULL)); | |
36f12725 NM |
2574 | } |
2575 | ||
2b4a568d JH |
2576 | /* vi: aw ai sw=2 |
2577 | */ | |
059ec3d9 | 2578 | /* End of tls-gnu.c */ |