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 | |
16 | Mavroyanopoulos. The revamp is partially a rewrite, partially cut&paste as | |
17 | appropriate. | |
059ec3d9 | 18 | |
17c76198 PP |
19 | APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, |
20 | which is not widely deployed by OS vendors. Will note issues below, which may | |
21 | assist in updating the code in the future. Another sources of hints is | |
22 | mod_gnutls for Apache (SNI callback registration and handling). | |
059ec3d9 | 23 | |
17c76198 PP |
24 | Keeping client and server variables more split than before and is currently |
25 | the norm, in anticipation of TLS in ACL callouts. | |
059ec3d9 | 26 | |
17c76198 PP |
27 | I wanted to switch to gnutls_certificate_set_verify_function() so that |
28 | certificate rejection could happen during handshake where it belongs, rather | |
29 | than being dropped afterwards, but that was introduced in 2.10.0 and Debian | |
30 | (6.0.5) is still on 2.8.6. So for now we have to stick with sub-par behaviour. | |
059ec3d9 | 31 | |
17c76198 PP |
32 | (I wasn't looking for libraries quite that old, when updating to get rid of |
33 | compiler warnings of deprecated APIs. If it turns out that a lot of the rest | |
34 | require current GnuTLS, then we'll drop support for the ancient libraries). | |
35 | */ | |
b5aea5e1 | 36 | |
17c76198 PP |
37 | #include <gnutls/gnutls.h> |
38 | /* needed for cert checks in verification and DN extraction: */ | |
39 | #include <gnutls/x509.h> | |
40 | /* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ | |
41 | #include <gnutls/crypto.h> | |
a5f239e4 PP |
42 | /* needed to disable PKCS11 autoload unless requested */ |
43 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
44 | # include <gnutls/pkcs11.h> | |
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 | |
7e07527a | 63 | |
f2de3a33 | 64 | #ifndef DISABLE_OCSP |
2b4a568d JH |
65 | # include <gnutls/ocsp.h> |
66 | #endif | |
059ec3d9 | 67 | |
17c76198 | 68 | /* GnuTLS 2 vs 3 |
059ec3d9 | 69 | |
17c76198 PP |
70 | GnuTLS 3 only: |
71 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 72 | |
17c76198 PP |
73 | Changes: |
74 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
75 | */ | |
059ec3d9 | 76 | |
17c76198 | 77 | /* Local static variables for GnuTLS */ |
059ec3d9 | 78 | |
17c76198 | 79 | /* Values for verify_requirement */ |
059ec3d9 | 80 | |
e51c7be2 | 81 | enum peer_verify_requirement |
aa2a70ba | 82 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 83 | |
17c76198 PP |
84 | /* This holds most state for server or client; with this, we can set up an |
85 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
86 | over the TLS variables available for expansion. | |
059ec3d9 | 87 | |
17c76198 PP |
88 | Some of these correspond to variables in globals.c; those variables will |
89 | be set to point to content in one of these instances, as appropriate for | |
90 | the stage of the process lifetime. | |
059ec3d9 | 91 | |
389ca47a | 92 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 93 | */ |
059ec3d9 | 94 | |
17c76198 | 95 | typedef struct exim_gnutls_state { |
9d1c15ef | 96 | gnutls_session_t session; |
17c76198 | 97 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 98 | gnutls_priority_t priority_cache; |
17c76198 | 99 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
100 | int fd_in; |
101 | int fd_out; | |
102 | BOOL peer_cert_verified; | |
103 | BOOL trigger_sni_changes; | |
104 | BOOL have_set_peerdn; | |
17c76198 | 105 | const struct host_item *host; |
9d1c15ef JH |
106 | gnutls_x509_crt_t peercert; |
107 | uschar *peerdn; | |
108 | uschar *ciphersuite; | |
109 | uschar *received_sni; | |
17c76198 PP |
110 | |
111 | const uschar *tls_certificate; | |
112 | const uschar *tls_privatekey; | |
113 | const uschar *tls_sni; /* client send only, not received */ | |
114 | const uschar *tls_verify_certificates; | |
115 | const uschar *tls_crl; | |
116 | const uschar *tls_require_ciphers; | |
e51c7be2 | 117 | |
17c76198 PP |
118 | uschar *exp_tls_certificate; |
119 | uschar *exp_tls_privatekey; | |
17c76198 PP |
120 | uschar *exp_tls_verify_certificates; |
121 | uschar *exp_tls_crl; | |
122 | uschar *exp_tls_require_ciphers; | |
44662487 | 123 | uschar *exp_tls_ocsp_file; |
55414b25 | 124 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 125 | #ifndef DISABLE_EVENT |
a7538db1 JH |
126 | uschar *event_action; |
127 | #endif | |
17c76198 | 128 | |
389ca47a | 129 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 130 | |
17c76198 PP |
131 | uschar *xfer_buffer; |
132 | int xfer_buffer_lwm; | |
133 | int xfer_buffer_hwm; | |
134 | int xfer_eof; | |
135 | int xfer_error; | |
17c76198 PP |
136 | } exim_gnutls_state_st; |
137 | ||
138 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 139 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 140 | NULL, NULL, NULL, NULL, |
17c76198 | 141 | NULL, NULL, NULL, NULL, NULL, NULL, |
44662487 | 142 | NULL, NULL, NULL, NULL, NULL, NULL, NULL, |
01a4a5c5 | 143 | NULL, |
0cbf2b82 | 144 | #ifndef DISABLE_EVENT |
a7538db1 | 145 | NULL, |
e51c7be2 | 146 | #endif |
817d9f57 | 147 | NULL, |
17c76198 | 148 | NULL, 0, 0, 0, 0, |
17c76198 | 149 | }; |
83da1223 | 150 | |
17c76198 PP |
151 | /* Not only do we have our own APIs which don't pass around state, assuming |
152 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
153 | for callbacks, or as part of the session, so we have to keep a "this is the | |
154 | context we're currently dealing with" pointer and rely upon being | |
155 | single-threaded to keep from processing data on an inbound TLS connection while | |
156 | talking to another TLS connection for an outbound check. This does mean that | |
157 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
158 | second connection. |
159 | XXX But see gnutls_session_get_ptr() | |
160 | */ | |
059ec3d9 | 161 | |
17c76198 | 162 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 163 | |
17c76198 PP |
164 | /* dh_params are initialised once within the lifetime of a process using TLS; |
165 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
166 | don't want to repeat this. */ | |
83da1223 | 167 | |
17c76198 | 168 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 169 | |
17c76198 | 170 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 171 | |
17c76198 | 172 | static const int ssl_session_timeout = 200; |
059ec3d9 | 173 | |
17c76198 | 174 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 175 | |
17c76198 | 176 | /* Guard library core initialisation */ |
83da1223 | 177 | |
17c76198 | 178 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 179 | |
4fb7df6d | 180 | #ifndef DISABLE_OCSP |
9196d5bf | 181 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 182 | #endif |
9196d5bf | 183 | |
059ec3d9 | 184 | |
17c76198 PP |
185 | /* ------------------------------------------------------------------------ */ |
186 | /* macros */ | |
83da1223 | 187 | |
17c76198 | 188 | #define MAX_HOST_LEN 255 |
83da1223 | 189 | |
17c76198 PP |
190 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
191 | the library logging; a value less than 0 disables the calls to set up logging | |
192 | callbacks. */ | |
2c17bb02 | 193 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 194 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 195 | #endif |
83da1223 | 196 | |
2c17bb02 | 197 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 198 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 199 | #endif |
83da1223 | 200 | |
af3498d6 PP |
201 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
202 | can ask for a bit-strength. Without that, we stick to the constant we had | |
203 | before, for now. */ | |
2c17bb02 | 204 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 205 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 206 | #endif |
af3498d6 | 207 | |
17c76198 PP |
208 | #define exim_gnutls_err_check(Label) do { \ |
209 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 210 | |
17c76198 | 211 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 212 | |
17c76198 | 213 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
214 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
215 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
216 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
217 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
218 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
219 | * isn't available sometimes, so this needs to become a conditional | |
220 | * compilation; the sanest way to deal with this being a problem on | |
221 | * older OSes is to block it in the Local/Makefile with this compiler | |
222 | * definition */ | |
e51c7be2 JH |
223 | # ifndef AVOID_GNUTLS_PKCS11 |
224 | # define HAVE_GNUTLS_PKCS11 | |
225 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 226 | #endif |
83da1223 | 227 | |
af3498d6 PP |
228 | |
229 | ||
230 | ||
231 | /* ------------------------------------------------------------------------ */ | |
232 | /* Callback declarations */ | |
233 | ||
234 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
235 | static void exim_gnutls_logger_cb(int level, const char *message); | |
236 | #endif | |
237 | ||
238 | static int exim_sni_handling_cb(gnutls_session_t session); | |
239 | ||
f2de3a33 | 240 | #ifndef DISABLE_OCSP |
44662487 JH |
241 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
242 | gnutls_datum_t * ocsp_response); | |
243 | #endif | |
af3498d6 PP |
244 | |
245 | ||
246 | ||
17c76198 PP |
247 | /* ------------------------------------------------------------------------ */ |
248 | /* Static functions */ | |
059ec3d9 PH |
249 | |
250 | /************************************************* | |
251 | * Handle TLS error * | |
252 | *************************************************/ | |
253 | ||
254 | /* Called from lots of places when errors occur before actually starting to do | |
255 | the TLS handshake, that is, while the session is still in clear. Always returns | |
256 | DEFER for a server and FAIL for a client so that most calls can use "return | |
257 | tls_error(...)" to do this processing and then give an appropriate return. A | |
258 | single function is used for both server and client, because it is called from | |
259 | some shared functions. | |
260 | ||
261 | Argument: | |
262 | prefix text to include in the logged error | |
7199e1ee TF |
263 | msg additional error string (may be NULL) |
264 | usually obtained from gnutls_strerror() | |
17c76198 PP |
265 | host NULL if setting up a server; |
266 | the connected host if setting up a client | |
059ec3d9 PH |
267 | |
268 | Returns: OK/DEFER/FAIL | |
269 | */ | |
270 | ||
271 | static int | |
17c76198 | 272 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 273 | { |
17c76198 PP |
274 | if (host) |
275 | { | |
c562fd30 | 276 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s)%s%s", |
17c76198 PP |
277 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); |
278 | return FAIL; | |
279 | } | |
280 | else | |
059ec3d9 | 281 | { |
7199e1ee | 282 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 283 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee | 284 | conn_info += 5; |
c562fd30 | 285 | /* I'd like to get separated H= here, but too hard for now */ |
7199e1ee | 286 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", |
17c76198 | 287 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
288 | return DEFER; |
289 | } | |
059ec3d9 PH |
290 | } |
291 | ||
292 | ||
293 | ||
17c76198 | 294 | |
059ec3d9 | 295 | /************************************************* |
17c76198 | 296 | * Deal with logging errors during I/O * |
059ec3d9 PH |
297 | *************************************************/ |
298 | ||
17c76198 | 299 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 300 | |
17c76198 PP |
301 | Argument: |
302 | state the current GnuTLS exim state container | |
303 | rc the GnuTLS error code, or 0 if it's a local error | |
304 | when text identifying read or write | |
305 | text local error text when ec is 0 | |
059ec3d9 | 306 | |
17c76198 | 307 | Returns: nothing |
059ec3d9 PH |
308 | */ |
309 | ||
17c76198 PP |
310 | static void |
311 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 312 | { |
17c76198 | 313 | const char *msg; |
059ec3d9 | 314 | |
17c76198 PP |
315 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
316 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
317 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
318 | else | |
319 | msg = gnutls_strerror(rc); | |
059ec3d9 | 320 | |
17c76198 PP |
321 | tls_error(when, msg, state->host); |
322 | } | |
059ec3d9 | 323 | |
059ec3d9 | 324 | |
059ec3d9 | 325 | |
059ec3d9 | 326 | |
17c76198 PP |
327 | /************************************************* |
328 | * Set various Exim expansion vars * | |
329 | *************************************************/ | |
059ec3d9 | 330 | |
e51c7be2 JH |
331 | #define exim_gnutls_cert_err(Label) \ |
332 | do \ | |
333 | { \ | |
334 | if (rc != GNUTLS_E_SUCCESS) \ | |
335 | { \ | |
336 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
337 | (Label), gnutls_strerror(rc)); \ | |
338 | return rc; \ | |
339 | } \ | |
340 | } while (0) | |
9d1c15ef JH |
341 | |
342 | static int | |
27f19eb4 | 343 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
344 | { |
345 | int rc; | |
346 | ||
347 | rc = gnutls_x509_crt_init(crtp); | |
348 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
349 | ||
350 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
351 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
352 | ||
353 | return rc; | |
354 | } | |
355 | ||
356 | #undef exim_gnutls_cert_err | |
357 | ||
358 | ||
17c76198 PP |
359 | /* We set various Exim global variables from the state, once a session has |
360 | been established. With TLS callouts, may need to change this to stack | |
361 | variables, or just re-call it with the server state after client callout | |
362 | has finished. | |
059ec3d9 | 363 | |
9d1c15ef | 364 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
365 | |
366 | Sets: | |
367 | tls_active fd | |
368 | tls_bits strength indicator | |
369 | tls_certificate_verified bool indicator | |
370 | tls_channelbinding_b64 for some SASL mechanisms | |
371 | tls_cipher a string | |
9d1c15ef | 372 | tls_peercert pointer to library internal |
17c76198 PP |
373 | tls_peerdn a string |
374 | tls_sni a (UTF-8) string | |
9d1c15ef | 375 | tls_ourcert pointer to library internal |
17c76198 PP |
376 | |
377 | Argument: | |
378 | state the relevant exim_gnutls_state_st * | |
379 | */ | |
380 | ||
381 | static void | |
9d1c15ef | 382 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 383 | { |
17c76198 | 384 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
385 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
386 | int old_pool; | |
387 | int rc; | |
388 | gnutls_datum_t channel; | |
389 | #endif | |
9d1c15ef | 390 | tls_support * tlsp = state->tlsp; |
17c76198 | 391 | |
9d1c15ef | 392 | tlsp->active = state->fd_out; |
17c76198 PP |
393 | |
394 | cipher = gnutls_cipher_get(state->session); | |
395 | /* returns size in "bytes" */ | |
9d1c15ef | 396 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 397 | |
9d1c15ef | 398 | tlsp->cipher = state->ciphersuite; |
17c76198 | 399 | |
817d9f57 | 400 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 401 | |
9d1c15ef | 402 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 403 | |
17c76198 PP |
404 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
405 | only available for use for authenticators while this TLS session is running. */ | |
406 | ||
407 | tls_channelbinding_b64 = NULL; | |
408 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
409 | channel.data = NULL; | |
410 | channel.size = 0; | |
411 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
412 | if (rc) { | |
413 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
414 | } else { | |
415 | old_pool = store_pool; | |
416 | store_pool = POOL_PERM; | |
f4d091fb | 417 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
418 | store_pool = old_pool; |
419 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
420 | } | |
421 | #endif | |
422 | ||
9d1c15ef JH |
423 | /* peercert is set in peer_status() */ |
424 | tlsp->peerdn = state->peerdn; | |
425 | tlsp->sni = state->received_sni; | |
426 | ||
427 | /* record our certificate */ | |
428 | { | |
27f19eb4 | 429 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
430 | gnutls_x509_crt_t crt; |
431 | ||
432 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
433 | } | |
059ec3d9 PH |
434 | } |
435 | ||
436 | ||
437 | ||
17c76198 | 438 | |
059ec3d9 | 439 | /************************************************* |
575643cd | 440 | * Setup up DH parameters * |
059ec3d9 PH |
441 | *************************************************/ |
442 | ||
575643cd | 443 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
444 | be re-generated every so often, depending on security policy. What we do is to |
445 | keep these parameters in a file in the spool directory. If the file does not | |
446 | exist, we generate them. This means that it is easy to cause a regeneration. | |
447 | ||
448 | The new file is written as a temporary file and renamed, so that an incomplete | |
449 | file is never present. If two processes both compute some new parameters, you | |
450 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
451 | prevent this. | |
452 | ||
059ec3d9 PH |
453 | Returns: OK/DEFER/FAIL |
454 | */ | |
455 | ||
456 | static int | |
17c76198 | 457 | init_server_dh(void) |
059ec3d9 | 458 | { |
17c76198 PP |
459 | int fd, rc; |
460 | unsigned int dh_bits; | |
27f19eb4 | 461 | gnutls_datum_t m; |
a799883d PP |
462 | uschar filename_buf[PATH_MAX]; |
463 | uschar *filename = NULL; | |
17c76198 | 464 | size_t sz; |
a799883d PP |
465 | uschar *exp_tls_dhparam; |
466 | BOOL use_file_in_spool = FALSE; | |
467 | BOOL use_fixed_file = FALSE; | |
17c76198 | 468 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 469 | |
17c76198 | 470 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 471 | |
17c76198 PP |
472 | rc = gnutls_dh_params_init(&dh_server_params); |
473 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 474 | |
a799883d PP |
475 | m.data = NULL; |
476 | m.size = 0; | |
477 | ||
478 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
479 | return DEFER; | |
480 | ||
481 | if (!exp_tls_dhparam) | |
482 | { | |
483 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
484 | m.data = US std_dh_prime_default(); | |
485 | m.size = Ustrlen(m.data); | |
486 | } | |
487 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
488 | use_file_in_spool = TRUE; | |
489 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
490 | { | |
491 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
492 | return OK; | |
493 | } | |
494 | else if (exp_tls_dhparam[0] != '/') | |
495 | { | |
496 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
497 | if (m.data == NULL) | |
498 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
499 | m.size = Ustrlen(m.data); | |
500 | } | |
501 | else | |
502 | { | |
503 | use_fixed_file = TRUE; | |
504 | filename = exp_tls_dhparam; | |
505 | } | |
506 | ||
507 | if (m.data) | |
508 | { | |
509 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
510 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
511 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
512 | return OK; | |
513 | } | |
514 | ||
af3498d6 PP |
515 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
516 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
517 | different filename and ensure we have sufficient bits. */ |
518 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
519 | if (!dh_bits) | |
520 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 521 | DEBUG(D_tls) |
b34fc30c | 522 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
523 | dh_bits); |
524 | #else | |
525 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
526 | DEBUG(D_tls) | |
527 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
528 | dh_bits); | |
529 | #endif | |
059ec3d9 | 530 | |
3375e053 PP |
531 | /* Some clients have hard-coded limits. */ |
532 | if (dh_bits > tls_dh_max_bits) | |
533 | { | |
534 | DEBUG(D_tls) | |
535 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
536 | tls_dh_max_bits); | |
537 | dh_bits = tls_dh_max_bits; | |
538 | } | |
539 | ||
a799883d PP |
540 | if (use_file_in_spool) |
541 | { | |
542 | if (!string_format(filename_buf, sizeof(filename_buf), | |
543 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
544 | return tls_error(US"overlong filename", NULL, NULL); | |
545 | filename = filename_buf; | |
546 | } | |
059ec3d9 | 547 | |
b5aea5e1 | 548 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 549 | parameters. */ |
059ec3d9 PH |
550 | |
551 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 552 | if (fd >= 0) |
059ec3d9 | 553 | { |
b5aea5e1 | 554 | struct stat statbuf; |
17c76198 PP |
555 | FILE *fp; |
556 | int saved_errno; | |
557 | ||
558 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
559 | { | |
560 | saved_errno = errno; | |
561 | (void)close(fd); | |
562 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
563 | } | |
564 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
565 | { |
566 | (void)close(fd); | |
17c76198 PP |
567 | return tls_error(US"TLS cache not a file", NULL, NULL); |
568 | } | |
40c90bca | 569 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
570 | { |
571 | saved_errno = errno; | |
572 | (void)close(fd); | |
573 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
574 | strerror(saved_errno), NULL); | |
b5aea5e1 | 575 | } |
059ec3d9 | 576 | |
b5aea5e1 | 577 | m.size = statbuf.st_size; |
40c90bca | 578 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
579 | { |
580 | fclose(fp); | |
581 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
582 | } | |
40c90bca | 583 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
584 | { |
585 | saved_errno = errno; | |
586 | fclose(fp); | |
587 | free(m.data); | |
588 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
589 | } | |
590 | fclose(fp); | |
b5aea5e1 | 591 | |
17c76198 | 592 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 593 | free(m.data); |
17c76198 PP |
594 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
595 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
596 | } |
597 | ||
598 | /* If the file does not exist, fall through to compute new data and cache it. | |
599 | If there was any other opening error, it is serious. */ | |
600 | ||
182ad5cf PH |
601 | else if (errno == ENOENT) |
602 | { | |
17c76198 | 603 | rc = -1; |
182ad5cf | 604 | DEBUG(D_tls) |
17c76198 | 605 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
606 | } |
607 | else | |
17c76198 PP |
608 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
609 | NULL, NULL); | |
b5aea5e1 PH |
610 | |
611 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
612 | is not useful. One particular case of this is when upgrading from an older | |
613 | release of Exim in which the data was stored in a different format. We don't | |
614 | try to be clever and support both formats; we just regenerate new data in this | |
615 | case. */ | |
616 | ||
17c76198 | 617 | if (rc < 0) |
b5aea5e1 | 618 | { |
17c76198 | 619 | uschar *temp_fn; |
201f5254 | 620 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 621 | |
17c76198 PP |
622 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
623 | return tls_error(US"Filename too long to generate replacement", | |
624 | CS filename, NULL); | |
059ec3d9 | 625 | |
17c76198 PP |
626 | temp_fn = string_copy(US "%s.XXXXXXX"); |
627 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 628 | if (fd < 0) |
17c76198 | 629 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
630 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
631 | ||
201f5254 PP |
632 | /* GnuTLS overshoots! |
633 | * If we ask for 2236, we might get 2237 or more. | |
634 | * But there's no way to ask GnuTLS how many bits there really are. | |
635 | * We can ask how many bits were used in a TLS session, but that's it! | |
636 | * The prime itself is hidden behind too much abstraction. | |
637 | * So we ask for less, and proceed on a wing and a prayer. | |
638 | * First attempt, subtracted 3 for 2233 and got 2240. | |
639 | */ | |
cae6e576 | 640 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
641 | { |
642 | dh_bits_gen = dh_bits - 10; | |
643 | DEBUG(D_tls) | |
644 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
645 | dh_bits_gen); | |
646 | } | |
647 | ||
648 | DEBUG(D_tls) | |
649 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
650 | dh_bits_gen); | |
651 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
652 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
653 | ||
654 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
655 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
656 | sample apps handle this. */ | |
657 | ||
658 | sz = 0; | |
659 | m.data = NULL; | |
660 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
661 | m.data, &sz); | |
662 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
663 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
664 | m.size = sz; | |
40c90bca | 665 | if (!(m.data = malloc(m.size))) |
17c76198 | 666 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
40c90bca | 667 | |
1f00591e | 668 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 669 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 670 | m.data, &sz); |
17c76198 PP |
671 | if (rc != GNUTLS_E_SUCCESS) |
672 | { | |
673 | free(m.data); | |
674 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
675 | } | |
1f00591e | 676 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 677 | |
17c76198 PP |
678 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
679 | if (sz != m.size) | |
680 | { | |
681 | free(m.data); | |
682 | return tls_error(US"TLS cache write D-H params failed", | |
683 | strerror(errno), NULL); | |
684 | } | |
b5aea5e1 | 685 | free(m.data); |
17c76198 PP |
686 | sz = write_to_fd_buf(fd, US"\n", 1); |
687 | if (sz != 1) | |
688 | return tls_error(US"TLS cache write D-H params final newline failed", | |
689 | strerror(errno), NULL); | |
690 | ||
691 | rc = close(fd); | |
692 | if (rc) | |
693 | return tls_error(US"TLS cache write close() failed", | |
694 | strerror(errno), NULL); | |
059ec3d9 | 695 | |
17c76198 PP |
696 | if (Urename(temp_fn, filename) < 0) |
697 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
698 | temp_fn, filename), strerror(errno), NULL); | |
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 | |
713 | tls_install_selfsign(exim_gnutls_state_st * state) | |
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: | |
771 | rc = tls_error(where, gnutls_strerror(rc), NULL); | |
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 * |
059ec3d9 PH |
792 | |
793 | Returns: OK/DEFER/FAIL | |
794 | */ | |
795 | ||
796 | static int | |
17c76198 | 797 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 798 | { |
1365611d | 799 | struct stat statbuf; |
059ec3d9 | 800 | int rc; |
17c76198 PP |
801 | const host_item *host = state->host; /* macro should be reconsidered? */ |
802 | uschar *saved_tls_certificate = NULL; | |
803 | uschar *saved_tls_privatekey = NULL; | |
804 | uschar *saved_tls_verify_certificates = NULL; | |
805 | uschar *saved_tls_crl = NULL; | |
806 | int cert_count; | |
807 | ||
808 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 809 | if (!host) /* server */ |
17c76198 PP |
810 | if (!state->received_sni) |
811 | { | |
d9b2312b JH |
812 | if (state->tls_certificate && |
813 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
814 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
815 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
816 | )) | |
17c76198 PP |
817 | { |
818 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
819 | state->trigger_sni_changes = TRUE; | |
820 | } | |
821 | } | |
822 | else | |
823 | { | |
1365611d | 824 | /* useful for debugging */ |
17c76198 PP |
825 | saved_tls_certificate = state->exp_tls_certificate; |
826 | saved_tls_privatekey = state->exp_tls_privatekey; | |
827 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
828 | saved_tls_crl = state->exp_tls_crl; | |
829 | } | |
059ec3d9 | 830 | |
1365611d PP |
831 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
832 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
833 | ||
17c76198 PP |
834 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
835 | state members, assuming consistent naming; and expand_check() returns | |
836 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 837 | |
17c76198 PP |
838 | /* check if we at least have a certificate, before doing expensive |
839 | D-H generation. */ | |
059ec3d9 | 840 | |
17c76198 PP |
841 | if (!expand_check_tlsvar(tls_certificate)) |
842 | return DEFER; | |
059ec3d9 | 843 | |
17c76198 | 844 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 845 | |
23bb6982 JH |
846 | if ( !state->exp_tls_certificate |
847 | || !*state->exp_tls_certificate | |
848 | ) | |
2b4a568d | 849 | if (!host) |
23bb6982 | 850 | return tls_install_selfsign(state); |
17c76198 PP |
851 | else |
852 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 853 | |
17c76198 | 854 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
855 | return DEFER; |
856 | ||
17c76198 PP |
857 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
858 | ||
859 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 860 | { |
17c76198 PP |
861 | state->tls_privatekey = state->tls_certificate; |
862 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 863 | } |
c91535f3 | 864 | |
059ec3d9 | 865 | |
17c76198 | 866 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
867 | { |
868 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
869 | state->exp_tls_certificate, state->exp_tls_privatekey); |
870 | ||
871 | if (state->received_sni) | |
23bb6982 JH |
872 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
873 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
874 | ) | |
17c76198 | 875 | { |
b34fc30c | 876 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
877 | } |
878 | else | |
879 | { | |
b34fc30c | 880 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 881 | } |
059ec3d9 | 882 | |
1365611d PP |
883 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
884 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
885 | GNUTLS_X509_FMT_PEM); | |
886 | exim_gnutls_err_check( | |
887 | string_sprintf("cert/key setup: cert=%s key=%s", | |
888 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
889 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 890 | } /* tls_certificate */ |
059ec3d9 | 891 | |
2b4a568d JH |
892 | |
893 | /* Set the OCSP stapling server info */ | |
894 | ||
f2de3a33 | 895 | #ifndef DISABLE_OCSP |
2b4a568d JH |
896 | if ( !host /* server */ |
897 | && tls_ocsp_file | |
898 | ) | |
899 | { | |
9196d5bf JH |
900 | if (gnutls_buggy_ocsp) |
901 | { | |
902 | DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
903 | } | |
904 | else | |
905 | { | |
906 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", | |
907 | &state->exp_tls_ocsp_file)) | |
908 | return DEFER; | |
2b4a568d | 909 | |
9196d5bf JH |
910 | /* Use the full callback method for stapling just to get observability. |
911 | More efficient would be to read the file once only, if it never changed | |
912 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
44662487 | 913 | |
9196d5bf JH |
914 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, |
915 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 916 | |
9196d5bf JH |
917 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file); |
918 | } | |
2b4a568d JH |
919 | } |
920 | #endif | |
921 | ||
922 | ||
059ec3d9 PH |
923 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
924 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
925 | error message is provided. However, if we just refrain from setting anything up | |
926 | in that case, certificate verification fails, which seems to be the correct | |
927 | behaviour. */ | |
928 | ||
610ff438 | 929 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 930 | { |
17c76198 | 931 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 932 | return DEFER; |
610ff438 JH |
933 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
934 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
935 | state->exp_tls_verify_certificates = NULL; | |
936 | #endif | |
17c76198 PP |
937 | if (state->tls_crl && *state->tls_crl) |
938 | if (!expand_check_tlsvar(tls_crl)) | |
939 | return DEFER; | |
059ec3d9 | 940 | |
1365611d PP |
941 | if (!(state->exp_tls_verify_certificates && |
942 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
943 | { |
944 | DEBUG(D_tls) | |
1365611d PP |
945 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
946 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 947 | return OK; |
b34fc30c | 948 | } |
1365611d | 949 | } |
83e2f8a2 PP |
950 | else |
951 | { | |
952 | DEBUG(D_tls) | |
953 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
954 | return OK; | |
955 | } | |
17c76198 | 956 | |
cb1d7830 JH |
957 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
958 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
959 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
960 | else | |
961 | #endif | |
1365611d | 962 | { |
cb1d7830 JH |
963 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
964 | { | |
965 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
966 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
967 | strerror(errno)); | |
968 | return DEFER; | |
969 | } | |
17c76198 | 970 | |
a7fec7a7 | 971 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
972 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
973 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
974 | other weirdness. The thing we really want to check is that it's not a | |
975 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 976 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
977 | if (S_ISDIR(statbuf.st_mode)) |
978 | { | |
979 | DEBUG(D_tls) | |
980 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
981 | state->exp_tls_verify_certificates); | |
982 | log_write(0, LOG_MAIN|LOG_PANIC, | |
983 | "tls_verify_certificates \"%s\" is a directory", | |
984 | state->exp_tls_verify_certificates); | |
985 | return DEFER; | |
986 | } | |
a7fec7a7 | 987 | #endif |
059ec3d9 | 988 | |
cb1d7830 JH |
989 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
990 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 991 | |
cb1d7830 JH |
992 | if (statbuf.st_size == 0) |
993 | { | |
994 | DEBUG(D_tls) | |
995 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
996 | return OK; | |
997 | } | |
059ec3d9 | 998 | |
cb1d7830 | 999 | cert_count = |
a7fec7a7 JH |
1000 | |
1001 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1002 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1003 | ? | |
1004 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1005 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1006 | : | |
a7fec7a7 | 1007 | #endif |
cb1d7830 JH |
1008 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1009 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1010 | } | |
a7fec7a7 | 1011 | |
1365611d PP |
1012 | if (cert_count < 0) |
1013 | { | |
1014 | rc = cert_count; | |
cb1d7830 | 1015 | exim_gnutls_err_check(US"setting certificate trust"); |
1365611d PP |
1016 | } |
1017 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1018 | |
5c8cda3a PP |
1019 | if (state->tls_crl && *state->tls_crl && |
1020 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1021 | { |
5c8cda3a PP |
1022 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1023 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1024 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1025 | if (cert_count < 0) | |
1365611d | 1026 | { |
5c8cda3a | 1027 | rc = cert_count; |
1365611d PP |
1028 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
1029 | } | |
5c8cda3a | 1030 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1031 | } |
059ec3d9 | 1032 | |
059ec3d9 PH |
1033 | return OK; |
1034 | } | |
1035 | ||
1036 | ||
1037 | ||
1038 | ||
1365611d PP |
1039 | /************************************************* |
1040 | * Set X.509 state variables * | |
1041 | *************************************************/ | |
1042 | ||
1043 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1044 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1045 | structure. Which means various other non-re-expanded pieces of state | |
1046 | need to be re-set in the new struct, so the setting logic is pulled | |
1047 | out to this. | |
1048 | ||
1049 | Arguments: | |
1050 | state exim_gnutls_state_st * | |
1051 | ||
1052 | Returns: OK/DEFER/FAIL | |
1053 | */ | |
1054 | ||
1055 | static int | |
1056 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
1057 | { | |
1058 | int rc; | |
1059 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1060 | ||
1061 | /* Create D-H parameters, or read them from the cache file. This function does | |
1062 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1063 | client-side params. */ | |
1064 | ||
1065 | if (!state->host) | |
1066 | { | |
1067 | if (!dh_server_params) | |
1068 | { | |
1069 | rc = init_server_dh(); | |
1070 | if (rc != OK) return rc; | |
1071 | } | |
1072 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1073 | } | |
1074 | ||
1075 | /* Link the credentials to the session. */ | |
1076 | ||
1077 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
1078 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
1079 | ||
1080 | return OK; | |
1081 | } | |
1082 | ||
059ec3d9 | 1083 | /************************************************* |
17c76198 | 1084 | * Initialize for GnuTLS * |
059ec3d9 PH |
1085 | *************************************************/ |
1086 | ||
9196d5bf | 1087 | |
4fb7df6d JH |
1088 | #ifndef DISABLE_OCSP |
1089 | ||
9196d5bf JH |
1090 | static BOOL |
1091 | tls_is_buggy_ocsp(void) | |
1092 | { | |
1093 | const uschar * s; | |
1094 | uschar maj, mid, mic; | |
1095 | ||
1096 | s = CUS gnutls_check_version(NULL); | |
1097 | maj = atoi(CCS s); | |
1098 | if (maj == 3) | |
1099 | { | |
1100 | while (*s && *s != '.') s++; | |
1101 | mid = atoi(CCS ++s); | |
1102 | if (mid <= 2) | |
1103 | return TRUE; | |
1104 | else if (mid >= 5) | |
1105 | return FALSE; | |
1106 | else | |
1107 | { | |
1108 | while (*s && *s != '.') s++; | |
1109 | mic = atoi(CCS ++s); | |
1110 | return mic <= (mid == 3 ? 16 : 3); | |
1111 | } | |
1112 | } | |
1113 | return FALSE; | |
1114 | } | |
1115 | ||
4fb7df6d | 1116 | #endif |
9196d5bf JH |
1117 | |
1118 | ||
17c76198 PP |
1119 | /* Called from both server and client code. In the case of a server, errors |
1120 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1121 | |
1122 | Arguments: | |
17c76198 PP |
1123 | host connected host, if client; NULL if server |
1124 | certificate certificate file | |
1125 | privatekey private key file | |
1126 | sni TLS SNI to send, sometimes when client; else NULL | |
1127 | cas CA certs file | |
1128 | crl CRL file | |
1129 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1130 | caller_state returned state-info structure |
059ec3d9 | 1131 | |
17c76198 | 1132 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1133 | */ |
1134 | ||
17c76198 PP |
1135 | static int |
1136 | tls_init( | |
1137 | const host_item *host, | |
1138 | const uschar *certificate, | |
1139 | const uschar *privatekey, | |
1140 | const uschar *sni, | |
1141 | const uschar *cas, | |
1142 | const uschar *crl, | |
1143 | const uschar *require_ciphers, | |
1144 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 1145 | { |
17c76198 PP |
1146 | exim_gnutls_state_st *state; |
1147 | int rc; | |
1148 | size_t sz; | |
1149 | const char *errpos; | |
1150 | uschar *p; | |
1151 | BOOL want_default_priorities; | |
1152 | ||
1153 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1154 | { |
17c76198 PP |
1155 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1156 | ||
a5f239e4 PP |
1157 | #ifdef HAVE_GNUTLS_PKCS11 |
1158 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1159 | which loads modules from a config file, which sounds good and may be wanted | |
1160 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1161 | environment variables are used and so breaks for users calling mailq. | |
1162 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1163 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1164 | { |
1165 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1166 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1167 | } | |
1168 | #endif | |
1169 | ||
17c76198 PP |
1170 | rc = gnutls_global_init(); |
1171 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1172 | ||
1173 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1174 | DEBUG(D_tls) | |
059ec3d9 | 1175 | { |
17c76198 PP |
1176 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1177 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1178 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1179 | } |
17c76198 PP |
1180 | #endif |
1181 | ||
4fb7df6d JH |
1182 | #ifndef DISABLE_OCSP |
1183 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1184 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1185 | #endif |
9196d5bf | 1186 | |
17c76198 | 1187 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1188 | } |
059ec3d9 | 1189 | |
17c76198 PP |
1190 | if (host) |
1191 | { | |
1192 | state = &state_client; | |
1193 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1194 | state->tlsp = &tls_out; |
17c76198 PP |
1195 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1196 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1197 | } | |
1198 | else | |
1199 | { | |
1200 | state = &state_server; | |
1201 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1202 | state->tlsp = &tls_in; |
17c76198 PP |
1203 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1204 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1205 | } | |
1206 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1207 | |
17c76198 | 1208 | state->host = host; |
059ec3d9 | 1209 | |
17c76198 PP |
1210 | state->tls_certificate = certificate; |
1211 | state->tls_privatekey = privatekey; | |
5779e6aa | 1212 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1213 | state->tls_sni = sni; |
1214 | state->tls_verify_certificates = cas; | |
1215 | state->tls_crl = crl; | |
059ec3d9 | 1216 | |
17c76198 PP |
1217 | /* This handles the variables that might get re-expanded after TLS SNI; |
1218 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1219 | |
17c76198 PP |
1220 | DEBUG(D_tls) |
1221 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
1222 | rc = tls_expand_session_files(state); | |
1223 | if (rc != OK) return rc; | |
059ec3d9 | 1224 | |
1365611d PP |
1225 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1226 | requires a new structure afterwards. */ | |
83da1223 | 1227 | |
1365611d PP |
1228 | rc = tls_set_remaining_x509(state); |
1229 | if (rc != OK) return rc; | |
83da1223 | 1230 | |
17c76198 PP |
1231 | /* set SNI in client, only */ |
1232 | if (host) | |
1233 | { | |
0df4ab80 | 1234 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni)) |
17c76198 | 1235 | return DEFER; |
0df4ab80 | 1236 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1237 | { |
1238 | DEBUG(D_tls) | |
0df4ab80 JH |
1239 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1240 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1241 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1242 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
17c76198 PP |
1243 | exim_gnutls_err_check(US"gnutls_server_name_set"); |
1244 | } | |
1245 | } | |
1246 | else if (state->tls_sni) | |
1247 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1248 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1249 | |
17c76198 | 1250 | /* This is the priority string support, |
42bfef1e | 1251 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1252 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1253 | This was backwards incompatible, but means Exim no longer needs to track | |
1254 | all algorithms and provide string forms for them. */ | |
83da1223 | 1255 | |
17c76198 | 1256 | want_default_priorities = TRUE; |
83da1223 | 1257 | |
17c76198 | 1258 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1259 | { |
17c76198 PP |
1260 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1261 | return DEFER; | |
1262 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1263 | { |
17c76198 PP |
1264 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1265 | state->exp_tls_require_ciphers); | |
1266 | ||
1267 | rc = gnutls_priority_init(&state->priority_cache, | |
1268 | CS state->exp_tls_require_ciphers, &errpos); | |
1269 | want_default_priorities = FALSE; | |
1270 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1271 | } |
1272 | } | |
17c76198 PP |
1273 | if (want_default_priorities) |
1274 | { | |
83e2f8a2 PP |
1275 | DEBUG(D_tls) |
1276 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1277 | exim_default_gnutls_priority); | |
17c76198 PP |
1278 | rc = gnutls_priority_init(&state->priority_cache, |
1279 | exim_default_gnutls_priority, &errpos); | |
1280 | p = US exim_default_gnutls_priority; | |
1281 | } | |
83da1223 | 1282 | |
17c76198 PP |
1283 | exim_gnutls_err_check(string_sprintf( |
1284 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1285 | p, errpos - CS p, errpos)); | |
1286 | ||
1287 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1288 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1289 | ||
1290 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1291 | ||
1292 | /* Reduce security in favour of increased compatibility, if the admin | |
1293 | decides to make that trade-off. */ | |
1294 | if (gnutls_compat_mode) | |
83da1223 | 1295 | { |
17c76198 PP |
1296 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1297 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1298 | gnutls_session_enable_compatibility_mode(state->session); | |
1299 | #else | |
1300 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1301 | #endif | |
83da1223 PH |
1302 | } |
1303 | ||
17c76198 | 1304 | *caller_state = state; |
17c76198 | 1305 | return OK; |
83da1223 PH |
1306 | } |
1307 | ||
1308 | ||
1309 | ||
059ec3d9 | 1310 | /************************************************* |
17c76198 | 1311 | * Extract peer information * |
059ec3d9 PH |
1312 | *************************************************/ |
1313 | ||
17c76198 | 1314 | /* Called from both server and client code. |
4fe99a6c PP |
1315 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1316 | and we use that to detect double-calls. | |
059ec3d9 | 1317 | |
75fe387d PP |
1318 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1319 | for logging in the server side, but for the client side, we log after teardown | |
1320 | in src/deliver.c. While the session is up, we can twist about states and | |
1321 | repoint tls_* globals, but those variables used for logging or other variable | |
1322 | expansion that happens _after_ delivery need to have a longer life-time. | |
1323 | ||
1324 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1325 | doing this more than once per generation of a state context. We set them in | |
1326 | the state context, and repoint tls_* to them. After the state goes away, the | |
1327 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1328 | ||
1329 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1330 | don't apply. | |
1331 | ||
059ec3d9 | 1332 | Arguments: |
17c76198 | 1333 | state exim_gnutls_state_st * |
059ec3d9 | 1334 | |
17c76198 | 1335 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1336 | */ |
1337 | ||
17c76198 PP |
1338 | static int |
1339 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1340 | { |
75fe387d | 1341 | uschar cipherbuf[256]; |
27f19eb4 | 1342 | const gnutls_datum_t *cert_list; |
75fe387d | 1343 | int old_pool, rc; |
17c76198 | 1344 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1345 | gnutls_protocol_t protocol; |
1346 | gnutls_cipher_algorithm_t cipher; | |
1347 | gnutls_kx_algorithm_t kx; | |
1348 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1349 | gnutls_certificate_type_t ct; |
1350 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1351 | uschar *p, *dn_buf; |
17c76198 | 1352 | size_t sz; |
059ec3d9 | 1353 | |
4fe99a6c | 1354 | if (state->have_set_peerdn) |
17c76198 | 1355 | return OK; |
4fe99a6c | 1356 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1357 | |
4fe99a6c | 1358 | state->peerdn = NULL; |
059ec3d9 | 1359 | |
4fe99a6c PP |
1360 | /* tls_cipher */ |
1361 | cipher = gnutls_cipher_get(state->session); | |
1362 | protocol = gnutls_protocol_get_version(state->session); | |
1363 | mac = gnutls_mac_get(state->session); | |
1364 | kx = gnutls_kx_get(state->session); | |
1365 | ||
75fe387d | 1366 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1367 | "%s:%s:%d", |
1368 | gnutls_protocol_get_name(protocol), | |
1369 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1370 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1371 | ||
1372 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1373 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1374 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1375 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1376 | if (isspace(*p)) |
1377 | *p = '-'; | |
75fe387d PP |
1378 | old_pool = store_pool; |
1379 | store_pool = POOL_PERM; | |
1380 | state->ciphersuite = string_copy(cipherbuf); | |
1381 | store_pool = old_pool; | |
817d9f57 | 1382 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1383 | |
1384 | /* tls_peerdn */ | |
17c76198 | 1385 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1386 | |
17c76198 PP |
1387 | if (cert_list == NULL || cert_list_size == 0) |
1388 | { | |
17c76198 PP |
1389 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1390 | cert_list, cert_list_size); | |
e51c7be2 | 1391 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1392 | return tls_error(US"certificate verification failed", |
1393 | "no certificate received from peer", state->host); | |
1394 | return OK; | |
1395 | } | |
059ec3d9 | 1396 | |
17c76198 PP |
1397 | ct = gnutls_certificate_type_get(state->session); |
1398 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1399 | { |
17c76198 | 1400 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1401 | DEBUG(D_tls) |
1402 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1403 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1404 | return tls_error(US"certificate verification not possible, unhandled type", |
1405 | ctn, state->host); | |
1406 | return OK; | |
83da1223 | 1407 | } |
059ec3d9 | 1408 | |
e51c7be2 JH |
1409 | #define exim_gnutls_peer_err(Label) \ |
1410 | do { \ | |
1411 | if (rc != GNUTLS_E_SUCCESS) \ | |
1412 | { \ | |
1413 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1414 | (Label), gnutls_strerror(rc)); \ | |
1415 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
1416 | return tls_error((Label), gnutls_strerror(rc), state->host); \ | |
1417 | return OK; \ | |
1418 | } \ | |
1419 | } while (0) | |
17c76198 | 1420 | |
9d1c15ef JH |
1421 | rc = import_cert(&cert_list[0], &crt); |
1422 | exim_gnutls_peer_err(US"cert 0"); | |
1423 | ||
1424 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1425 | |
17c76198 PP |
1426 | sz = 0; |
1427 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1428 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1429 | { |
17c76198 PP |
1430 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1431 | return FAIL; /* should not happen */ | |
059ec3d9 | 1432 | } |
17c76198 PP |
1433 | dn_buf = store_get_perm(sz); |
1434 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1435 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1436 | |
17c76198 PP |
1437 | state->peerdn = dn_buf; |
1438 | ||
1439 | return OK; | |
1440 | #undef exim_gnutls_peer_err | |
1441 | } | |
059ec3d9 | 1442 | |
059ec3d9 | 1443 | |
059ec3d9 | 1444 | |
059ec3d9 | 1445 | |
17c76198 PP |
1446 | /************************************************* |
1447 | * Verify peer certificate * | |
1448 | *************************************************/ | |
059ec3d9 | 1449 | |
17c76198 PP |
1450 | /* Called from both server and client code. |
1451 | *Should* be using a callback registered with | |
1452 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1453 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1454 | |
17c76198 PP |
1455 | Arguments: |
1456 | state exim_gnutls_state_st * | |
1457 | error where to put an error message | |
059ec3d9 | 1458 | |
17c76198 PP |
1459 | Returns: |
1460 | FALSE if the session should be rejected | |
1461 | TRUE if the cert is okay or we just don't care | |
1462 | */ | |
059ec3d9 | 1463 | |
17c76198 PP |
1464 | static BOOL |
1465 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1466 | { | |
1467 | int rc; | |
1468 | unsigned int verify; | |
1469 | ||
1470 | *error = NULL; | |
1471 | ||
0a92f87f | 1472 | if ((rc = peer_status(state)) != OK) |
e6060e2c | 1473 | { |
17c76198 | 1474 | verify = GNUTLS_CERT_INVALID; |
0a92f87f | 1475 | *error = "certificate not supplied"; |
17c76198 PP |
1476 | } |
1477 | else | |
17c76198 | 1478 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1479 | |
17c76198 PP |
1480 | /* Handle the result of verification. INVALID seems to be set as well |
1481 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1482 | |
e51c7be2 JH |
1483 | if (rc < 0 || |
1484 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1485 | ) | |
17c76198 PP |
1486 | { |
1487 | state->peer_cert_verified = FALSE; | |
0a92f87f JH |
1488 | if (!*error) |
1489 | *error = verify & GNUTLS_CERT_REVOKED | |
1490 | ? "certificate revoked" : "certificate invalid"; | |
059ec3d9 | 1491 | |
17c76198 | 1492 | DEBUG(D_tls) |
e51c7be2 | 1493 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
4fe99a6c | 1494 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1495 | |
e51c7be2 | 1496 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1497 | { |
e51c7be2 JH |
1498 | gnutls_alert_send(state->session, |
1499 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1500 | return FALSE; |
1501 | } | |
1502 | DEBUG(D_tls) | |
4789da3a | 1503 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1504 | } |
e51c7be2 | 1505 | |
17c76198 PP |
1506 | else |
1507 | { | |
aa2a70ba | 1508 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1509 | { |
1510 | int sep = 0; | |
55414b25 | 1511 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 | 1512 | uschar * name; |
76075bb5 | 1513 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) |
e51c7be2 JH |
1514 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) |
1515 | break; | |
1516 | if (!name) | |
1517 | { | |
1518 | DEBUG(D_tls) | |
1519 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba JH |
1520 | if (state->verify_requirement >= VERIFY_REQUIRED) |
1521 | { | |
1522 | gnutls_alert_send(state->session, | |
1523 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1524 | return FALSE; | |
1525 | } | |
1526 | return TRUE; | |
e51c7be2 JH |
1527 | } |
1528 | } | |
17c76198 | 1529 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1530 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1531 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1532 | } |
059ec3d9 | 1533 | |
817d9f57 | 1534 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1535 | |
17c76198 PP |
1536 | return TRUE; |
1537 | } | |
059ec3d9 | 1538 | |
17c76198 PP |
1539 | |
1540 | ||
1541 | ||
1542 | /* ------------------------------------------------------------------------ */ | |
1543 | /* Callbacks */ | |
1544 | ||
1545 | /* Logging function which can be registered with | |
1546 | * gnutls_global_set_log_function() | |
1547 | * gnutls_global_set_log_level() 0..9 | |
1548 | */ | |
af3498d6 | 1549 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1550 | static void |
17c76198 | 1551 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1552 | { |
8c79eebf PP |
1553 | size_t len = strlen(message); |
1554 | if (len < 1) | |
1555 | { | |
1556 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1557 | return; | |
1558 | } | |
1559 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1560 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1561 | } |
af3498d6 | 1562 | #endif |
059ec3d9 | 1563 | |
059ec3d9 | 1564 | |
17c76198 PP |
1565 | /* Called after client hello, should handle SNI work. |
1566 | This will always set tls_sni (state->received_sni) if available, | |
1567 | and may trigger presenting different certificates, | |
1568 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1569 | |
17c76198 PP |
1570 | Should be registered with |
1571 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1572 | |
17c76198 PP |
1573 | "This callback must return 0 on success or a gnutls error code to terminate the |
1574 | handshake.". | |
059ec3d9 | 1575 | |
17c76198 PP |
1576 | For inability to get SNI information, we return 0. |
1577 | We only return non-zero if re-setup failed. | |
817d9f57 | 1578 | Only used for server-side TLS. |
17c76198 | 1579 | */ |
44bbabb5 | 1580 | |
17c76198 PP |
1581 | static int |
1582 | exim_sni_handling_cb(gnutls_session_t session) | |
1583 | { | |
1584 | char sni_name[MAX_HOST_LEN]; | |
1585 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1586 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1587 | unsigned int sni_type; |
1588 | int rc, old_pool; | |
1589 | ||
1590 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1591 | if (rc != GNUTLS_E_SUCCESS) |
1592 | { | |
1593 | DEBUG(D_tls) { | |
1594 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1595 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1596 | else | |
1597 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1598 | gnutls_strerror(rc), rc); | |
1599 | }; | |
1600 | return 0; | |
1601 | } | |
1602 | ||
17c76198 PP |
1603 | if (sni_type != GNUTLS_NAME_DNS) |
1604 | { | |
1605 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1606 | return 0; | |
1607 | } | |
44bbabb5 | 1608 | |
17c76198 PP |
1609 | /* We now have a UTF-8 string in sni_name */ |
1610 | old_pool = store_pool; | |
1611 | store_pool = POOL_PERM; | |
1612 | state->received_sni = string_copyn(US sni_name, data_len); | |
1613 | store_pool = old_pool; | |
1614 | ||
1615 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1616 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1617 | |
1618 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1619 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1620 | ||
1621 | if (!state->trigger_sni_changes) | |
1622 | return 0; | |
1623 | ||
1624 | rc = tls_expand_session_files(state); | |
1625 | if (rc != OK) | |
1626 | { | |
1627 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1628 | been offered. The best we can do now is abort. */ | |
1629 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1630 | } | |
1631 | ||
1365611d PP |
1632 | rc = tls_set_remaining_x509(state); |
1633 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1634 | ||
1635 | return 0; | |
059ec3d9 PH |
1636 | } |
1637 | ||
1638 | ||
1639 | ||
f2de3a33 | 1640 | #ifndef DISABLE_OCSP |
44662487 JH |
1641 | |
1642 | static int | |
1643 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1644 | gnutls_datum_t * ocsp_response) | |
1645 | { | |
1646 | int ret; | |
1647 | ||
44662487 JH |
1648 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1649 | { | |
1650 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
1651 | (char *)ptr); | |
018058b2 | 1652 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1653 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1654 | } | |
1655 | ||
018058b2 | 1656 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1657 | return 0; |
1658 | } | |
1659 | ||
1660 | #endif | |
1661 | ||
1662 | ||
0cbf2b82 | 1663 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1664 | /* |
1665 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1666 | for an exim TLS connection (either direction), raising a tls:cert event |
1667 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1668 | can deny verification. |
1669 | ||
1670 | Return 0 for the handshake to continue or non-zero to terminate. | |
1671 | */ | |
1672 | ||
1673 | static int | |
723fe533 | 1674 | verify_cb(gnutls_session_t session) |
a7538db1 | 1675 | { |
27f19eb4 | 1676 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1677 | unsigned int cert_list_size = 0; |
1678 | gnutls_x509_crt_t crt; | |
1679 | int rc; | |
b30275b8 | 1680 | uschar * yield; |
a7538db1 JH |
1681 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1682 | ||
1683 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1684 | if (cert_list) | |
1685 | while (cert_list_size--) | |
1686 | { | |
1687 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1688 | if (rc != GNUTLS_E_SUCCESS) | |
1689 | { | |
1690 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1691 | cert_list_size, gnutls_strerror(rc)); | |
1692 | break; | |
1693 | } | |
1694 | ||
1695 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1696 | if ((yield = event_raise(state->event_action, |
1697 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1698 | { |
1699 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1700 | "SSL verify denied by event-action: depth=%d: %s", |
1701 | cert_list_size, yield); | |
a7538db1 JH |
1702 | return 1; /* reject */ |
1703 | } | |
1704 | state->tlsp->peercert = NULL; | |
1705 | } | |
1706 | ||
1707 | return 0; | |
1708 | } | |
1709 | ||
1710 | #endif | |
44662487 JH |
1711 | |
1712 | ||
17c76198 PP |
1713 | |
1714 | /* ------------------------------------------------------------------------ */ | |
1715 | /* Exported functions */ | |
1716 | ||
1717 | ||
1718 | ||
1719 | ||
059ec3d9 PH |
1720 | /************************************************* |
1721 | * Start a TLS session in a server * | |
1722 | *************************************************/ | |
1723 | ||
1724 | /* This is called when Exim is running as a server, after having received | |
1725 | the STARTTLS command. It must respond to that command, and then negotiate | |
1726 | a TLS session. | |
1727 | ||
1728 | Arguments: | |
83da1223 | 1729 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1730 | |
1731 | Returns: OK on success | |
1732 | DEFER for errors before the start of the negotiation | |
1733 | FAIL for errors during the negotation; the server can't | |
1734 | continue running. | |
1735 | */ | |
1736 | ||
1737 | int | |
17c76198 | 1738 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1739 | { |
1740 | int rc; | |
7199e1ee | 1741 | const char *error; |
17c76198 | 1742 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1743 | |
1744 | /* Check for previous activation */ | |
817d9f57 | 1745 | if (tls_in.active >= 0) |
059ec3d9 | 1746 | { |
17c76198 | 1747 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1748 | smtp_printf("554 Already in TLS\r\n"); |
1749 | return FAIL; | |
1750 | } | |
1751 | ||
1752 | /* Initialize the library. If it fails, it will already have logged the error | |
1753 | and sent an SMTP response. */ | |
1754 | ||
17c76198 | 1755 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1756 | |
17c76198 PP |
1757 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1758 | NULL, tls_verify_certificates, tls_crl, | |
1759 | require_ciphers, &state); | |
059ec3d9 PH |
1760 | if (rc != OK) return rc; |
1761 | ||
059ec3d9 PH |
1762 | /* If this is a host for which certificate verification is mandatory or |
1763 | optional, set up appropriately. */ | |
1764 | ||
059ec3d9 | 1765 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1766 | { |
e51c7be2 JH |
1767 | DEBUG(D_tls) |
1768 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1769 | state->verify_requirement = VERIFY_REQUIRED; |
1770 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1771 | } | |
059ec3d9 | 1772 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1773 | { |
e51c7be2 JH |
1774 | DEBUG(D_tls) |
1775 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1776 | state->verify_requirement = VERIFY_OPTIONAL; |
1777 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1778 | } | |
1779 | else | |
1780 | { | |
e51c7be2 JH |
1781 | DEBUG(D_tls) |
1782 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1783 | state->verify_requirement = VERIFY_NONE; |
1784 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1785 | } | |
059ec3d9 | 1786 | |
0cbf2b82 | 1787 | #ifndef DISABLE_EVENT |
723fe533 JH |
1788 | if (event_action) |
1789 | { | |
1790 | state->event_action = event_action; | |
1791 | gnutls_session_set_ptr(state->session, state); | |
1792 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
1793 | } | |
1794 | #endif | |
1795 | ||
17c76198 PP |
1796 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1797 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1798 | |
17c76198 PP |
1799 | gnutls_handshake_set_post_client_hello_function(state->session, |
1800 | exim_sni_handling_cb); | |
059ec3d9 PH |
1801 | |
1802 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1803 | on connection, where outputting anything now upsets the clients and tends to | |
1804 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1805 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1806 | mode, the fflush() happens when smtp_getc() is called. */ | |
1807 | ||
817d9f57 | 1808 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1809 | { |
1810 | smtp_printf("220 TLS go ahead\r\n"); | |
9d1c15ef | 1811 | fflush(smtp_out); |
059ec3d9 PH |
1812 | } |
1813 | ||
1814 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1815 | that the GnuTLS library doesn't. */ | |
1816 | ||
17c76198 | 1817 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
1818 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
1819 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
1820 | state->fd_in = fileno(smtp_in); |
1821 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1822 | |
1823 | sigalrm_seen = FALSE; | |
1824 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1825 | do |
17c76198 | 1826 | rc = gnutls_handshake(state->session); |
157a7880 | 1827 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
1828 | alarm(0); |
1829 | ||
17c76198 | 1830 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1831 | { |
059ec3d9 PH |
1832 | /* It seems that, except in the case of a timeout, we have to close the |
1833 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1834 | until the server times out. */ | |
1835 | ||
60d10ce7 JH |
1836 | if (sigalrm_seen) |
1837 | tls_error(US"gnutls_handshake", "timed out", NULL); | |
1838 | else | |
059ec3d9 | 1839 | { |
60d10ce7 JH |
1840 | tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL); |
1841 | gnutls_alert_send_appropriate(state->session, rc); | |
1842 | millisleep(500); | |
1843 | shutdown(fileno(smtp_out), SHUT_WR); | |
1844 | for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ | |
f1e894f3 PH |
1845 | (void)fclose(smtp_out); |
1846 | (void)fclose(smtp_in); | |
60d10ce7 | 1847 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
1848 | } |
1849 | ||
1850 | return FAIL; | |
1851 | } | |
1852 | ||
1853 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1854 | ||
17c76198 PP |
1855 | /* Verify after the fact */ |
1856 | ||
9d1c15ef JH |
1857 | if ( state->verify_requirement != VERIFY_NONE |
1858 | && !verify_certificate(state, &error)) | |
059ec3d9 | 1859 | { |
9d1c15ef | 1860 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1861 | { |
9d1c15ef JH |
1862 | tls_error(US"certificate verification failed", error, NULL); |
1863 | return FAIL; | |
17c76198 | 1864 | } |
9d1c15ef JH |
1865 | DEBUG(D_tls) |
1866 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1867 | error); | |
059ec3d9 PH |
1868 | } |
1869 | ||
17c76198 PP |
1870 | /* Figure out peer DN, and if authenticated, etc. */ |
1871 | ||
60d10ce7 | 1872 | if ((rc = peer_status(state)) != OK) return rc; |
17c76198 PP |
1873 | |
1874 | /* Sets various Exim expansion variables; always safe within server */ | |
1875 | ||
9d1c15ef | 1876 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1877 | |
1878 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1879 | and initialize appropriately. */ | |
1880 | ||
17c76198 | 1881 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1882 | |
1883 | receive_getc = tls_getc; | |
584e96c6 | 1884 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
1885 | receive_ungetc = tls_ungetc; |
1886 | receive_feof = tls_feof; | |
1887 | receive_ferror = tls_ferror; | |
58eb016e | 1888 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1889 | |
059ec3d9 PH |
1890 | return OK; |
1891 | } | |
1892 | ||
1893 | ||
1894 | ||
1895 | ||
aa2a70ba JH |
1896 | static void |
1897 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
1898 | smtp_transport_options_block * ob) | |
1899 | { | |
5130845b | 1900 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 1901 | { |
4af0d74a | 1902 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 1903 | #ifdef SUPPORT_I18N |
4af0d74a JH |
1904 | string_domain_utf8_to_alabel(host->name, NULL); |
1905 | #else | |
1906 | host->name; | |
1907 | #endif | |
aa2a70ba JH |
1908 | DEBUG(D_tls) |
1909 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
1910 | state->exp_tls_verify_cert_hostnames); | |
1911 | } | |
1912 | } | |
aa2a70ba JH |
1913 | |
1914 | ||
059ec3d9 PH |
1915 | /************************************************* |
1916 | * Start a TLS session in a client * | |
1917 | *************************************************/ | |
1918 | ||
1919 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1920 | ||
1921 | Arguments: | |
1922 | fd the fd of the connection | |
1923 | host connected host (for messages) | |
83da1223 | 1924 | addr the first address (not used) |
a7538db1 | 1925 | tb transport (always smtp) |
059ec3d9 PH |
1926 | |
1927 | Returns: OK/DEFER/FAIL (because using common functions), | |
1928 | but for a client, DEFER and FAIL have the same meaning | |
1929 | */ | |
1930 | ||
1931 | int | |
17c76198 | 1932 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1933 | address_item *addr ARG_UNUSED, |
0e66b3b6 JH |
1934 | transport_instance *tb |
1935 | #ifdef EXPERIMENTAL_DANE | |
b2ba1b4c | 1936 | , dns_answer * unused_tlsa_dnsa |
0e66b3b6 JH |
1937 | #endif |
1938 | ) | |
059ec3d9 | 1939 | { |
a7538db1 JH |
1940 | smtp_transport_options_block *ob = |
1941 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 1942 | int rc; |
17c76198 PP |
1943 | const char *error; |
1944 | exim_gnutls_state_st *state = NULL; | |
f2de3a33 | 1945 | #ifndef DISABLE_OCSP |
5130845b JH |
1946 | BOOL require_ocsp = |
1947 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 1948 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 1949 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 1950 | #endif |
059ec3d9 | 1951 | |
17c76198 | 1952 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1953 | |
65867078 JH |
1954 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
1955 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
1956 | ob->tls_require_ciphers, &state)) != OK) | |
2b4a568d | 1957 | return rc; |
059ec3d9 | 1958 | |
54c90be1 | 1959 | { |
65867078 JH |
1960 | int dh_min_bits = ob->tls_dh_min_bits; |
1961 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
1962 | { | |
1963 | DEBUG(D_tls) | |
1964 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
1965 | " clamping %d up to %d\n", | |
1966 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1967 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1968 | } | |
54c90be1 | 1969 | |
65867078 JH |
1970 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
1971 | " acceptable bits to %d\n", | |
1972 | dh_min_bits); | |
1973 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
1974 | } | |
83da1223 | 1975 | |
94431adb | 1976 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
1977 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
1978 | the specified host patterns if one of them is defined */ | |
1979 | ||
aa2a70ba JH |
1980 | if ( ( state->exp_tls_verify_certificates |
1981 | && !ob->tls_verify_hosts | |
610ff438 | 1982 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) |
aa2a70ba | 1983 | ) |
5130845b | 1984 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK |
2b4a568d | 1985 | ) |
17c76198 | 1986 | { |
aa2a70ba | 1987 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
1988 | DEBUG(D_tls) |
1989 | debug_printf("TLS: server certificate verification required.\n"); | |
1990 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
1991 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
1992 | } | |
5130845b | 1993 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 1994 | { |
aa2a70ba | 1995 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
1996 | DEBUG(D_tls) |
1997 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 1998 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
1999 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2000 | } | |
2001 | else | |
2002 | { | |
e51c7be2 JH |
2003 | DEBUG(D_tls) |
2004 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2005 | state->verify_requirement = VERIFY_NONE; |
2006 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2007 | } |
059ec3d9 | 2008 | |
f2de3a33 JH |
2009 | #ifndef DISABLE_OCSP |
2010 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2011 | if (request_ocsp) |
9d1c15ef JH |
2012 | { |
2013 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2014 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2015 | NULL, 0, NULL)) != OK) | |
9d1c15ef JH |
2016 | return tls_error(US"cert-status-req", |
2017 | gnutls_strerror(rc), state->host); | |
44662487 | 2018 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2019 | } |
2b4a568d JH |
2020 | #endif |
2021 | ||
0cbf2b82 | 2022 | #ifndef DISABLE_EVENT |
774ef2d7 | 2023 | if (tb->event_action) |
a7538db1 | 2024 | { |
774ef2d7 | 2025 | state->event_action = tb->event_action; |
a7538db1 | 2026 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2027 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2028 | } |
2029 | #endif | |
2030 | ||
27f19eb4 | 2031 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2032 | state->fd_in = fd; |
2033 | state->fd_out = fd; | |
059ec3d9 | 2034 | |
9d1c15ef | 2035 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2036 | /* There doesn't seem to be a built-in timeout on connection. */ |
2037 | ||
2038 | sigalrm_seen = FALSE; | |
65867078 | 2039 | alarm(ob->command_timeout); |
17c76198 PP |
2040 | do |
2041 | { | |
2042 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
2043 | } while ((rc == GNUTLS_E_AGAIN) || |
2044 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
2045 | alarm(0); |
2046 | ||
4fe99a6c | 2047 | if (rc != GNUTLS_E_SUCCESS) |
60d10ce7 JH |
2048 | if (sigalrm_seen) |
2049 | { | |
2050 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
2051 | return tls_error(US"gnutls_handshake", "timed out", state->host); | |
2052 | } | |
2053 | else | |
2054 | return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host); | |
4fe99a6c | 2055 | |
17c76198 | 2056 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2057 | |
17c76198 | 2058 | /* Verify late */ |
059ec3d9 | 2059 | |
17c76198 PP |
2060 | if (state->verify_requirement != VERIFY_NONE && |
2061 | !verify_certificate(state, &error)) | |
2062 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 2063 | |
f2de3a33 | 2064 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2065 | if (require_ocsp) |
2066 | { | |
2067 | DEBUG(D_tls) | |
2068 | { | |
2069 | gnutls_datum_t stapling; | |
2070 | gnutls_ocsp_resp_t resp; | |
2071 | gnutls_datum_t printed; | |
2072 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2073 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2074 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2075 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2076 | ) | |
2077 | { | |
65867078 | 2078 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2079 | gnutls_free(printed.data); |
2080 | } | |
2081 | else | |
2082 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); | |
2083 | } | |
2084 | ||
2b4a568d | 2085 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2086 | { |
2087 | tls_out.ocsp = OCSP_FAILED; | |
2b4a568d | 2088 | return tls_error(US"certificate status check failed", NULL, state->host); |
018058b2 | 2089 | } |
2b4a568d | 2090 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2091 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2092 | } |
2093 | #endif | |
2094 | ||
17c76198 | 2095 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2096 | |
2b4a568d JH |
2097 | if ((rc = peer_status(state)) != OK) |
2098 | return rc; | |
059ec3d9 | 2099 | |
4fe99a6c | 2100 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2101 | |
9d1c15ef | 2102 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2103 | |
059ec3d9 PH |
2104 | return OK; |
2105 | } | |
2106 | ||
2107 | ||
2108 | ||
17c76198 | 2109 | |
059ec3d9 | 2110 | /************************************************* |
17c76198 | 2111 | * Close down a TLS session * |
059ec3d9 PH |
2112 | *************************************************/ |
2113 | ||
17c76198 PP |
2114 | /* This is also called from within a delivery subprocess forked from the |
2115 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2116 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2117 | |
17c76198 PP |
2118 | Arguments: TRUE if gnutls_bye is to be called |
2119 | Returns: nothing | |
059ec3d9 PH |
2120 | */ |
2121 | ||
17c76198 | 2122 | void |
817d9f57 | 2123 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2124 | { |
817d9f57 | 2125 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2126 | |
389ca47a | 2127 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2128 | |
2129 | if (shutdown) | |
2130 | { | |
60d10ce7 | 2131 | DEBUG(D_tls) debug_printf("tls_close() from '%s': shutting down TLS\n"); |
17c76198 PP |
2132 | gnutls_bye(state->session, GNUTLS_SHUT_WR); |
2133 | } | |
2134 | ||
2135 | gnutls_deinit(state->session); | |
2136 | ||
389ca47a | 2137 | state->tlsp->active = -1; |
17c76198 PP |
2138 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2139 | ||
2140 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2141 | { | |
2142 | gnutls_global_deinit(); | |
2143 | exim_gnutls_base_init_done = FALSE; | |
2144 | } | |
7199e1ee | 2145 | |
059ec3d9 PH |
2146 | } |
2147 | ||
2148 | ||
2149 | ||
17c76198 | 2150 | |
059ec3d9 PH |
2151 | /************************************************* |
2152 | * TLS version of getc * | |
2153 | *************************************************/ | |
2154 | ||
2155 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2156 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2157 | Only used by the server-side TLS. |
059ec3d9 | 2158 | |
17c76198 PP |
2159 | This feeds DKIM and should be used for all message-body reads. |
2160 | ||
059ec3d9 PH |
2161 | Arguments: none |
2162 | Returns: the next character or EOF | |
2163 | */ | |
2164 | ||
2165 | int | |
2166 | tls_getc(void) | |
2167 | { | |
817d9f57 | 2168 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 2169 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 2170 | { |
17c76198 | 2171 | ssize_t inbytes; |
059ec3d9 | 2172 | |
17c76198 PP |
2173 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
2174 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
2175 | |
2176 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 2177 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
2178 | ssl_xfer_buffer_size); |
2179 | alarm(0); | |
2180 | ||
60d10ce7 JH |
2181 | /* Timeouts do not get this far; see command_timeout_handler(). |
2182 | A zero-byte return appears to mean that the TLS session has been | |
059ec3d9 PH |
2183 | closed down, not that the socket itself has been closed down. Revert to |
2184 | non-TLS handling. */ | |
2185 | ||
60d10ce7 JH |
2186 | if (sigalrm_seen) |
2187 | { | |
2188 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
2189 | state->xfer_error = 1; | |
2190 | return EOF; | |
2191 | } | |
2192 | ||
2193 | else if (inbytes == 0) | |
059ec3d9 PH |
2194 | { |
2195 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2196 | ||
2197 | receive_getc = smtp_getc; | |
584e96c6 | 2198 | receive_get_cache = smtp_get_cache; |
059ec3d9 PH |
2199 | receive_ungetc = smtp_ungetc; |
2200 | receive_feof = smtp_feof; | |
2201 | receive_ferror = smtp_ferror; | |
58eb016e | 2202 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 2203 | |
17c76198 PP |
2204 | gnutls_deinit(state->session); |
2205 | state->session = NULL; | |
817d9f57 JH |
2206 | state->tlsp->active = -1; |
2207 | state->tlsp->bits = 0; | |
2208 | state->tlsp->certificate_verified = FALSE; | |
9d1c15ef | 2209 | tls_channelbinding_b64 = NULL; |
817d9f57 | 2210 | state->tlsp->cipher = NULL; |
9d1c15ef | 2211 | state->tlsp->peercert = NULL; |
817d9f57 | 2212 | state->tlsp->peerdn = NULL; |
059ec3d9 PH |
2213 | |
2214 | return smtp_getc(); | |
2215 | } | |
2216 | ||
2217 | /* Handle genuine errors */ | |
2218 | ||
2219 | else if (inbytes < 0) | |
2220 | { | |
17c76198 PP |
2221 | record_io_error(state, (int) inbytes, US"recv", NULL); |
2222 | state->xfer_error = 1; | |
059ec3d9 PH |
2223 | return EOF; |
2224 | } | |
80a47a2c | 2225 | #ifndef DISABLE_DKIM |
17c76198 | 2226 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 2227 | #endif |
17c76198 PP |
2228 | state->xfer_buffer_hwm = (int) inbytes; |
2229 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
2230 | } |
2231 | ||
059ec3d9 PH |
2232 | /* Something in the buffer; return next uschar */ |
2233 | ||
17c76198 | 2234 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
2235 | } |
2236 | ||
584e96c6 JH |
2237 | void |
2238 | tls_get_cache() | |
2239 | { | |
9960d1e5 | 2240 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2241 | exim_gnutls_state_st * state = &state_server; |
2242 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2243 | if (n > 0) | |
2244 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2245 | #endif |
9960d1e5 | 2246 | } |
584e96c6 | 2247 | |
059ec3d9 PH |
2248 | |
2249 | ||
17c76198 | 2250 | |
059ec3d9 PH |
2251 | /************************************************* |
2252 | * Read bytes from TLS channel * | |
2253 | *************************************************/ | |
2254 | ||
17c76198 PP |
2255 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2256 | then the caller must feed DKIM. | |
817d9f57 | 2257 | |
059ec3d9 PH |
2258 | Arguments: |
2259 | buff buffer of data | |
2260 | len size of buffer | |
2261 | ||
2262 | Returns: the number of bytes read | |
2263 | -1 after a failed read | |
2264 | */ | |
2265 | ||
2266 | int | |
817d9f57 | 2267 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2268 | { |
817d9f57 | 2269 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2270 | ssize_t inbytes; |
059ec3d9 | 2271 | |
17c76198 PP |
2272 | if (len > INT_MAX) |
2273 | len = INT_MAX; | |
059ec3d9 | 2274 | |
17c76198 PP |
2275 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2276 | DEBUG(D_tls) | |
2277 | debug_printf("*** PROBABLY A BUG *** " \ | |
2278 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2279 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2280 | ||
2281 | DEBUG(D_tls) | |
2282 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2283 | state->session, buff, len); | |
2284 | ||
2285 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2286 | if (inbytes > 0) return inbytes; |
2287 | if (inbytes == 0) | |
2288 | { | |
2289 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2290 | } | |
17c76198 | 2291 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2292 | |
2293 | return -1; | |
2294 | } | |
2295 | ||
2296 | ||
2297 | ||
17c76198 | 2298 | |
059ec3d9 PH |
2299 | /************************************************* |
2300 | * Write bytes down TLS channel * | |
2301 | *************************************************/ | |
2302 | ||
2303 | /* | |
2304 | Arguments: | |
817d9f57 | 2305 | is_server channel specifier |
059ec3d9 PH |
2306 | buff buffer of data |
2307 | len number of bytes | |
2308 | ||
2309 | Returns: the number of bytes after a successful write, | |
2310 | -1 after a failed write | |
2311 | */ | |
2312 | ||
2313 | int | |
817d9f57 | 2314 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 2315 | { |
17c76198 PP |
2316 | ssize_t outbytes; |
2317 | size_t left = len; | |
817d9f57 | 2318 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2319 | |
17c76198 | 2320 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
2321 | while (left > 0) |
2322 | { | |
17c76198 PP |
2323 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2324 | buff, left); | |
2325 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2326 | |
17c76198 | 2327 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2328 | if (outbytes < 0) |
2329 | { | |
17c76198 | 2330 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2331 | return -1; |
2332 | } | |
2333 | if (outbytes == 0) | |
2334 | { | |
17c76198 | 2335 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2336 | return -1; |
2337 | } | |
2338 | ||
2339 | left -= outbytes; | |
2340 | buff += outbytes; | |
2341 | } | |
2342 | ||
17c76198 PP |
2343 | if (len > INT_MAX) |
2344 | { | |
2345 | DEBUG(D_tls) | |
2346 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2347 | len); | |
2348 | len = INT_MAX; | |
2349 | } | |
2350 | ||
2351 | return (int) len; | |
059ec3d9 PH |
2352 | } |
2353 | ||
2354 | ||
2355 | ||
17c76198 | 2356 | |
059ec3d9 | 2357 | /************************************************* |
17c76198 | 2358 | * Random number generation * |
059ec3d9 PH |
2359 | *************************************************/ |
2360 | ||
17c76198 PP |
2361 | /* Pseudo-random number generation. The result is not expected to be |
2362 | cryptographically strong but not so weak that someone will shoot themselves | |
2363 | in the foot using it as a nonce in input in some email header scheme or | |
2364 | whatever weirdness they'll twist this into. The result should handle fork() | |
2365 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2366 | |
17c76198 PP |
2367 | Arguments: |
2368 | max range maximum | |
2369 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2370 | */ |
2371 | ||
af3498d6 | 2372 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2373 | int |
2374 | vaguely_random_number(int max) | |
059ec3d9 | 2375 | { |
17c76198 PP |
2376 | unsigned int r; |
2377 | int i, needed_len; | |
2378 | uschar *p; | |
2379 | uschar smallbuf[sizeof(r)]; | |
2380 | ||
2381 | if (max <= 1) | |
2382 | return 0; | |
2383 | ||
2384 | needed_len = sizeof(r); | |
2385 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2386 | * asked for a number less than 10. */ | |
2387 | for (r = max, i = 0; r; ++i) | |
2388 | r >>= 1; | |
2389 | i = (i + 7) / 8; | |
2390 | if (i < needed_len) | |
2391 | needed_len = i; | |
2392 | ||
2393 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2394 | if (i < 0) | |
059ec3d9 | 2395 | { |
17c76198 PP |
2396 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2397 | return vaguely_random_number_fallback(max); | |
2398 | } | |
2399 | r = 0; | |
2400 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2401 | { | |
2402 | r *= 256; | |
2403 | r += *p; | |
059ec3d9 PH |
2404 | } |
2405 | ||
17c76198 PP |
2406 | /* We don't particularly care about weighted results; if someone wants |
2407 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2408 | return r % max; | |
059ec3d9 | 2409 | } |
af3498d6 PP |
2410 | #else /* HAVE_GNUTLS_RND */ |
2411 | int | |
2412 | vaguely_random_number(int max) | |
2413 | { | |
2414 | return vaguely_random_number_fallback(max); | |
2415 | } | |
2416 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2417 | |
36f12725 NM |
2418 | |
2419 | ||
2420 | ||
3375e053 PP |
2421 | /************************************************* |
2422 | * Let tls_require_ciphers be checked at startup * | |
2423 | *************************************************/ | |
2424 | ||
2425 | /* The tls_require_ciphers option, if set, must be something which the | |
2426 | library can parse. | |
2427 | ||
2428 | Returns: NULL on success, or error message | |
2429 | */ | |
2430 | ||
2431 | uschar * | |
2432 | tls_validate_require_cipher(void) | |
2433 | { | |
2434 | int rc; | |
2435 | uschar *expciphers = NULL; | |
2436 | gnutls_priority_t priority_cache; | |
2437 | const char *errpos; | |
2438 | ||
2439 | #define validate_check_rc(Label) do { \ | |
2440 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2441 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2442 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2443 | ||
2444 | if (exim_gnutls_base_init_done) | |
2445 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2446 | "already initialised GnuTLS, Exim developer bug"); | |
2447 | ||
a5f239e4 | 2448 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2449 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2450 | { |
2451 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2452 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2453 | } | |
2454 | #endif | |
3375e053 PP |
2455 | rc = gnutls_global_init(); |
2456 | validate_check_rc(US"gnutls_global_init()"); | |
2457 | exim_gnutls_base_init_done = TRUE; | |
2458 | ||
2459 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2460 | return_deinit(NULL); | |
2461 | ||
2462 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2463 | return_deinit(US"failed to expand tls_require_ciphers"); | |
2464 | ||
2465 | if (!(expciphers && *expciphers)) | |
2466 | return_deinit(NULL); | |
2467 | ||
2468 | DEBUG(D_tls) | |
2469 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2470 | ||
2471 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2472 | validate_check_rc(string_sprintf( | |
2473 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2474 | expciphers, errpos - CS expciphers, errpos)); | |
2475 | ||
2476 | #undef return_deinit | |
2477 | #undef validate_check_rc | |
2478 | gnutls_global_deinit(); | |
2479 | ||
2480 | return NULL; | |
2481 | } | |
2482 | ||
2483 | ||
2484 | ||
2485 | ||
36f12725 NM |
2486 | /************************************************* |
2487 | * Report the library versions. * | |
2488 | *************************************************/ | |
2489 | ||
2490 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2491 | ||
2492 | Arguments: a FILE* to print the results to | |
2493 | Returns: nothing | |
2494 | */ | |
2495 | ||
2496 | void | |
2497 | tls_version_report(FILE *f) | |
2498 | { | |
754a0503 PP |
2499 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2500 | " Runtime: %s\n", | |
2501 | LIBGNUTLS_VERSION, | |
2502 | gnutls_check_version(NULL)); | |
36f12725 NM |
2503 | } |
2504 | ||
2b4a568d JH |
2505 | /* vi: aw ai sw=2 |
2506 | */ | |
059ec3d9 | 2507 | /* End of tls-gnu.c */ |