Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
3386088d | 5 | /* Copyright (c) University of Cambridge 1995 - 2015 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
17c76198 | 8 | /* Copyright (c) Phil Pennock 2012 */ |
059ec3d9 | 9 | |
17c76198 PP |
10 | /* This file provides TLS/SSL support for Exim using the GnuTLS library, |
11 | one of the available supported implementations. This file is #included into | |
12 | tls.c when USE_GNUTLS has been set. | |
059ec3d9 | 13 | |
17c76198 PP |
14 | The code herein is a revamp of GnuTLS integration using the current APIs; the |
15 | original tls-gnu.c was based on a patch which was contributed by Nikos | |
6aa6fc9c | 16 | Mavrogiannopoulos. The revamp is partially a rewrite, partially cut&paste as |
17c76198 | 17 | appropriate. |
059ec3d9 | 18 | |
17c76198 PP |
19 | APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, |
20 | which is not widely deployed by OS vendors. Will note issues below, which may | |
21 | assist in updating the code in the future. Another sources of hints is | |
22 | mod_gnutls for Apache (SNI callback registration and handling). | |
059ec3d9 | 23 | |
17c76198 PP |
24 | Keeping client and server variables more split than before and is currently |
25 | the norm, in anticipation of TLS in ACL callouts. | |
059ec3d9 | 26 | |
17c76198 PP |
27 | I wanted to switch to gnutls_certificate_set_verify_function() so that |
28 | certificate rejection could happen during handshake where it belongs, rather | |
29 | than being dropped afterwards, but that was introduced in 2.10.0 and Debian | |
30 | (6.0.5) is still on 2.8.6. So for now we have to stick with sub-par behaviour. | |
059ec3d9 | 31 | |
17c76198 PP |
32 | (I wasn't looking for libraries quite that old, when updating to get rid of |
33 | compiler warnings of deprecated APIs. If it turns out that a lot of the rest | |
34 | require current GnuTLS, then we'll drop support for the ancient libraries). | |
35 | */ | |
b5aea5e1 | 36 | |
17c76198 PP |
37 | #include <gnutls/gnutls.h> |
38 | /* needed for cert checks in verification and DN extraction: */ | |
39 | #include <gnutls/x509.h> | |
40 | /* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ | |
41 | #include <gnutls/crypto.h> | |
a5f239e4 PP |
42 | /* needed to disable PKCS11 autoload unless requested */ |
43 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
44 | # include <gnutls/pkcs11.h> | |
76075bb5 | 45 | # define SUPPORT_PARAM_TO_PK_BITS |
a5f239e4 | 46 | #endif |
7e07527a JH |
47 | #if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) |
48 | # warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" | |
49 | # define DISABLE_OCSP | |
50 | #endif | |
0cbf2b82 | 51 | #if GNUTLS_VERSION_NUMBER < 0x020a00 && !defined(DISABLE_EVENT) |
774ef2d7 | 52 | # warning "GnuTLS library version too old; tls:cert event unsupported" |
0cbf2b82 | 53 | # define DISABLE_EVENT |
a7538db1 | 54 | #endif |
a7fec7a7 JH |
55 | #if GNUTLS_VERSION_NUMBER >= 0x030306 |
56 | # define SUPPORT_CA_DIR | |
57 | #else | |
58 | # undef SUPPORT_CA_DIR | |
59 | #endif | |
11a04b5a | 60 | #if GNUTLS_VERSION_NUMBER >= 0x030014 |
cb1d7830 JH |
61 | # define SUPPORT_SYSDEFAULT_CABUNDLE |
62 | #endif | |
925ac8e4 JH |
63 | #if GNUTLS_VERSION_NUMBER >= 0x030109 |
64 | # define SUPPORT_CORK | |
65 | #endif | |
7e07527a | 66 | |
f2de3a33 | 67 | #ifndef DISABLE_OCSP |
2b4a568d JH |
68 | # include <gnutls/ocsp.h> |
69 | #endif | |
059ec3d9 | 70 | |
17c76198 | 71 | /* GnuTLS 2 vs 3 |
059ec3d9 | 72 | |
17c76198 PP |
73 | GnuTLS 3 only: |
74 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 75 | |
17c76198 PP |
76 | Changes: |
77 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
78 | */ | |
059ec3d9 | 79 | |
17c76198 | 80 | /* Local static variables for GnuTLS */ |
059ec3d9 | 81 | |
17c76198 | 82 | /* Values for verify_requirement */ |
059ec3d9 | 83 | |
e51c7be2 | 84 | enum peer_verify_requirement |
aa2a70ba | 85 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 86 | |
17c76198 PP |
87 | /* This holds most state for server or client; with this, we can set up an |
88 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
89 | over the TLS variables available for expansion. | |
059ec3d9 | 90 | |
17c76198 PP |
91 | Some of these correspond to variables in globals.c; those variables will |
92 | be set to point to content in one of these instances, as appropriate for | |
93 | the stage of the process lifetime. | |
059ec3d9 | 94 | |
389ca47a | 95 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 96 | */ |
059ec3d9 | 97 | |
17c76198 | 98 | typedef struct exim_gnutls_state { |
9d1c15ef | 99 | gnutls_session_t session; |
17c76198 | 100 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 101 | gnutls_priority_t priority_cache; |
17c76198 | 102 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
103 | int fd_in; |
104 | int fd_out; | |
105 | BOOL peer_cert_verified; | |
106 | BOOL trigger_sni_changes; | |
107 | BOOL have_set_peerdn; | |
17c76198 | 108 | const struct host_item *host; |
9d1c15ef JH |
109 | gnutls_x509_crt_t peercert; |
110 | uschar *peerdn; | |
111 | uschar *ciphersuite; | |
112 | uschar *received_sni; | |
17c76198 PP |
113 | |
114 | const uschar *tls_certificate; | |
115 | const uschar *tls_privatekey; | |
116 | const uschar *tls_sni; /* client send only, not received */ | |
117 | const uschar *tls_verify_certificates; | |
118 | const uschar *tls_crl; | |
119 | const uschar *tls_require_ciphers; | |
e51c7be2 | 120 | |
17c76198 PP |
121 | uschar *exp_tls_certificate; |
122 | uschar *exp_tls_privatekey; | |
17c76198 PP |
123 | uschar *exp_tls_verify_certificates; |
124 | uschar *exp_tls_crl; | |
125 | uschar *exp_tls_require_ciphers; | |
44662487 | 126 | uschar *exp_tls_ocsp_file; |
55414b25 | 127 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 128 | #ifndef DISABLE_EVENT |
a7538db1 JH |
129 | uschar *event_action; |
130 | #endif | |
17c76198 | 131 | |
389ca47a | 132 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 133 | |
17c76198 PP |
134 | uschar *xfer_buffer; |
135 | int xfer_buffer_lwm; | |
136 | int xfer_buffer_hwm; | |
137 | int xfer_eof; | |
138 | int xfer_error; | |
17c76198 PP |
139 | } exim_gnutls_state_st; |
140 | ||
141 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
f2ed27cf JH |
142 | .session = NULL, |
143 | .x509_cred = NULL, | |
144 | .priority_cache = NULL, | |
145 | .verify_requirement = VERIFY_NONE, | |
146 | .fd_in = -1, | |
147 | .fd_out = -1, | |
148 | .peer_cert_verified = FALSE, | |
149 | .trigger_sni_changes =FALSE, | |
150 | .have_set_peerdn = FALSE, | |
151 | .host = NULL, | |
152 | .peercert = NULL, | |
153 | .peerdn = NULL, | |
154 | .ciphersuite = NULL, | |
155 | .received_sni = NULL, | |
156 | ||
157 | .tls_certificate = NULL, | |
158 | .tls_privatekey = NULL, | |
159 | .tls_sni = NULL, | |
160 | .tls_verify_certificates = NULL, | |
161 | .tls_crl = NULL, | |
162 | .tls_require_ciphers =NULL, | |
163 | ||
164 | .exp_tls_certificate = NULL, | |
165 | .exp_tls_privatekey = NULL, | |
166 | .exp_tls_verify_certificates = NULL, | |
167 | .exp_tls_crl = NULL, | |
168 | .exp_tls_require_ciphers = NULL, | |
169 | .exp_tls_ocsp_file = NULL, | |
170 | .exp_tls_verify_cert_hostnames = NULL, | |
0cbf2b82 | 171 | #ifndef DISABLE_EVENT |
f2ed27cf | 172 | .event_action = NULL, |
e51c7be2 | 173 | #endif |
f2ed27cf JH |
174 | .tlsp = NULL, |
175 | ||
176 | .xfer_buffer = NULL, | |
177 | .xfer_buffer_lwm = 0, | |
178 | .xfer_buffer_hwm = 0, | |
179 | .xfer_eof = 0, | |
180 | .xfer_error = 0, | |
17c76198 | 181 | }; |
83da1223 | 182 | |
17c76198 PP |
183 | /* Not only do we have our own APIs which don't pass around state, assuming |
184 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
185 | for callbacks, or as part of the session, so we have to keep a "this is the | |
186 | context we're currently dealing with" pointer and rely upon being | |
187 | single-threaded to keep from processing data on an inbound TLS connection while | |
188 | talking to another TLS connection for an outbound check. This does mean that | |
189 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
190 | second connection. |
191 | XXX But see gnutls_session_get_ptr() | |
192 | */ | |
059ec3d9 | 193 | |
17c76198 | 194 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 195 | |
17c76198 PP |
196 | /* dh_params are initialised once within the lifetime of a process using TLS; |
197 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
198 | don't want to repeat this. */ | |
83da1223 | 199 | |
17c76198 | 200 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 201 | |
17c76198 | 202 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 203 | |
17c76198 | 204 | static const int ssl_session_timeout = 200; |
059ec3d9 | 205 | |
17c76198 | 206 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 207 | |
17c76198 | 208 | /* Guard library core initialisation */ |
83da1223 | 209 | |
17c76198 | 210 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 211 | |
4fb7df6d | 212 | #ifndef DISABLE_OCSP |
9196d5bf | 213 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 214 | #endif |
9196d5bf | 215 | |
059ec3d9 | 216 | |
17c76198 PP |
217 | /* ------------------------------------------------------------------------ */ |
218 | /* macros */ | |
83da1223 | 219 | |
17c76198 | 220 | #define MAX_HOST_LEN 255 |
83da1223 | 221 | |
17c76198 PP |
222 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
223 | the library logging; a value less than 0 disables the calls to set up logging | |
224 | callbacks. */ | |
2c17bb02 | 225 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 226 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 227 | #endif |
83da1223 | 228 | |
2c17bb02 | 229 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 230 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 231 | #endif |
83da1223 | 232 | |
af3498d6 PP |
233 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
234 | can ask for a bit-strength. Without that, we stick to the constant we had | |
235 | before, for now. */ | |
2c17bb02 | 236 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 237 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 238 | #endif |
af3498d6 | 239 | |
17c76198 | 240 | #define exim_gnutls_err_check(Label) do { \ |
cf0c6164 JH |
241 | if (rc != GNUTLS_E_SUCCESS) \ |
242 | return tls_error((Label), gnutls_strerror(rc), host, errstr); \ | |
243 | } while (0) | |
059ec3d9 | 244 | |
cf0c6164 JH |
245 | #define expand_check_tlsvar(Varname, errstr) \ |
246 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 247 | |
17c76198 | 248 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
249 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
250 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
251 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
252 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
253 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
254 | * isn't available sometimes, so this needs to become a conditional | |
255 | * compilation; the sanest way to deal with this being a problem on | |
256 | * older OSes is to block it in the Local/Makefile with this compiler | |
257 | * definition */ | |
e51c7be2 JH |
258 | # ifndef AVOID_GNUTLS_PKCS11 |
259 | # define HAVE_GNUTLS_PKCS11 | |
260 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 261 | #endif |
83da1223 | 262 | |
af3498d6 PP |
263 | |
264 | ||
265 | ||
266 | /* ------------------------------------------------------------------------ */ | |
267 | /* Callback declarations */ | |
268 | ||
269 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
270 | static void exim_gnutls_logger_cb(int level, const char *message); | |
271 | #endif | |
272 | ||
273 | static int exim_sni_handling_cb(gnutls_session_t session); | |
274 | ||
f2de3a33 | 275 | #ifndef DISABLE_OCSP |
44662487 JH |
276 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
277 | gnutls_datum_t * ocsp_response); | |
278 | #endif | |
af3498d6 PP |
279 | |
280 | ||
281 | ||
17c76198 PP |
282 | /* ------------------------------------------------------------------------ */ |
283 | /* Static functions */ | |
059ec3d9 PH |
284 | |
285 | /************************************************* | |
286 | * Handle TLS error * | |
287 | *************************************************/ | |
288 | ||
289 | /* Called from lots of places when errors occur before actually starting to do | |
290 | the TLS handshake, that is, while the session is still in clear. Always returns | |
291 | DEFER for a server and FAIL for a client so that most calls can use "return | |
292 | tls_error(...)" to do this processing and then give an appropriate return. A | |
293 | single function is used for both server and client, because it is called from | |
294 | some shared functions. | |
295 | ||
296 | Argument: | |
297 | prefix text to include in the logged error | |
7199e1ee TF |
298 | msg additional error string (may be NULL) |
299 | usually obtained from gnutls_strerror() | |
17c76198 PP |
300 | host NULL if setting up a server; |
301 | the connected host if setting up a client | |
cf0c6164 | 302 | errstr pointer to returned error string |
059ec3d9 PH |
303 | |
304 | Returns: OK/DEFER/FAIL | |
305 | */ | |
306 | ||
307 | static int | |
cf0c6164 JH |
308 | tls_error(const uschar *prefix, const char *msg, const host_item *host, |
309 | uschar ** errstr) | |
059ec3d9 | 310 | { |
cf0c6164 JH |
311 | if (errstr) |
312 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); | |
313 | return host ? FAIL : DEFER; | |
059ec3d9 PH |
314 | } |
315 | ||
316 | ||
317 | ||
17c76198 | 318 | |
059ec3d9 | 319 | /************************************************* |
17c76198 | 320 | * Deal with logging errors during I/O * |
059ec3d9 PH |
321 | *************************************************/ |
322 | ||
17c76198 | 323 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 324 | |
17c76198 PP |
325 | Argument: |
326 | state the current GnuTLS exim state container | |
327 | rc the GnuTLS error code, or 0 if it's a local error | |
328 | when text identifying read or write | |
329 | text local error text when ec is 0 | |
059ec3d9 | 330 | |
17c76198 | 331 | Returns: nothing |
059ec3d9 PH |
332 | */ |
333 | ||
17c76198 PP |
334 | static void |
335 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 336 | { |
cf0c6164 JH |
337 | const char * msg; |
338 | uschar * errstr; | |
059ec3d9 | 339 | |
17c76198 PP |
340 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
341 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
342 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
343 | else | |
344 | msg = gnutls_strerror(rc); | |
059ec3d9 | 345 | |
cf0c6164 JH |
346 | (void) tls_error(when, msg, state->host, &errstr); |
347 | ||
348 | if (state->host) | |
349 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
350 | state->host->name, state->host->address, errstr); | |
351 | else | |
352 | { | |
353 | uschar * conn_info = smtp_get_connection_info(); | |
354 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
355 | /* I'd like to get separated H= here, but too hard for now */ | |
356 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
357 | } | |
17c76198 | 358 | } |
059ec3d9 | 359 | |
059ec3d9 | 360 | |
059ec3d9 | 361 | |
059ec3d9 | 362 | |
17c76198 PP |
363 | /************************************************* |
364 | * Set various Exim expansion vars * | |
365 | *************************************************/ | |
059ec3d9 | 366 | |
e51c7be2 JH |
367 | #define exim_gnutls_cert_err(Label) \ |
368 | do \ | |
369 | { \ | |
370 | if (rc != GNUTLS_E_SUCCESS) \ | |
371 | { \ | |
372 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
373 | (Label), gnutls_strerror(rc)); \ | |
374 | return rc; \ | |
375 | } \ | |
376 | } while (0) | |
9d1c15ef JH |
377 | |
378 | static int | |
27f19eb4 | 379 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
380 | { |
381 | int rc; | |
382 | ||
383 | rc = gnutls_x509_crt_init(crtp); | |
384 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
385 | ||
386 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
387 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
388 | ||
389 | return rc; | |
390 | } | |
391 | ||
392 | #undef exim_gnutls_cert_err | |
393 | ||
394 | ||
17c76198 PP |
395 | /* We set various Exim global variables from the state, once a session has |
396 | been established. With TLS callouts, may need to change this to stack | |
397 | variables, or just re-call it with the server state after client callout | |
398 | has finished. | |
059ec3d9 | 399 | |
9d1c15ef | 400 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
401 | |
402 | Sets: | |
403 | tls_active fd | |
404 | tls_bits strength indicator | |
405 | tls_certificate_verified bool indicator | |
406 | tls_channelbinding_b64 for some SASL mechanisms | |
407 | tls_cipher a string | |
9d1c15ef | 408 | tls_peercert pointer to library internal |
17c76198 PP |
409 | tls_peerdn a string |
410 | tls_sni a (UTF-8) string | |
9d1c15ef | 411 | tls_ourcert pointer to library internal |
17c76198 PP |
412 | |
413 | Argument: | |
414 | state the relevant exim_gnutls_state_st * | |
415 | */ | |
416 | ||
417 | static void | |
9d1c15ef | 418 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 419 | { |
17c76198 | 420 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
421 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
422 | int old_pool; | |
423 | int rc; | |
424 | gnutls_datum_t channel; | |
425 | #endif | |
9d1c15ef | 426 | tls_support * tlsp = state->tlsp; |
17c76198 | 427 | |
9d1c15ef | 428 | tlsp->active = state->fd_out; |
17c76198 PP |
429 | |
430 | cipher = gnutls_cipher_get(state->session); | |
431 | /* returns size in "bytes" */ | |
9d1c15ef | 432 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 433 | |
9d1c15ef | 434 | tlsp->cipher = state->ciphersuite; |
17c76198 | 435 | |
817d9f57 | 436 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 437 | |
9d1c15ef | 438 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 439 | |
17c76198 PP |
440 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
441 | only available for use for authenticators while this TLS session is running. */ | |
442 | ||
443 | tls_channelbinding_b64 = NULL; | |
444 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
445 | channel.data = NULL; | |
446 | channel.size = 0; | |
447 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
448 | if (rc) { | |
449 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
450 | } else { | |
451 | old_pool = store_pool; | |
452 | store_pool = POOL_PERM; | |
f4d091fb | 453 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
454 | store_pool = old_pool; |
455 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
456 | } | |
457 | #endif | |
458 | ||
9d1c15ef JH |
459 | /* peercert is set in peer_status() */ |
460 | tlsp->peerdn = state->peerdn; | |
461 | tlsp->sni = state->received_sni; | |
462 | ||
463 | /* record our certificate */ | |
464 | { | |
27f19eb4 | 465 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
466 | gnutls_x509_crt_t crt; |
467 | ||
468 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
469 | } | |
059ec3d9 PH |
470 | } |
471 | ||
472 | ||
473 | ||
17c76198 | 474 | |
059ec3d9 | 475 | /************************************************* |
575643cd | 476 | * Setup up DH parameters * |
059ec3d9 PH |
477 | *************************************************/ |
478 | ||
575643cd | 479 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
480 | be re-generated every so often, depending on security policy. What we do is to |
481 | keep these parameters in a file in the spool directory. If the file does not | |
482 | exist, we generate them. This means that it is easy to cause a regeneration. | |
483 | ||
484 | The new file is written as a temporary file and renamed, so that an incomplete | |
485 | file is never present. If two processes both compute some new parameters, you | |
486 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
487 | prevent this. | |
488 | ||
059ec3d9 PH |
489 | Returns: OK/DEFER/FAIL |
490 | */ | |
491 | ||
492 | static int | |
cf0c6164 | 493 | init_server_dh(uschar ** errstr) |
059ec3d9 | 494 | { |
17c76198 PP |
495 | int fd, rc; |
496 | unsigned int dh_bits; | |
27f19eb4 | 497 | gnutls_datum_t m; |
a799883d PP |
498 | uschar filename_buf[PATH_MAX]; |
499 | uschar *filename = NULL; | |
17c76198 | 500 | size_t sz; |
a799883d PP |
501 | uschar *exp_tls_dhparam; |
502 | BOOL use_file_in_spool = FALSE; | |
503 | BOOL use_fixed_file = FALSE; | |
17c76198 | 504 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 505 | |
17c76198 | 506 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 507 | |
17c76198 PP |
508 | rc = gnutls_dh_params_init(&dh_server_params); |
509 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 510 | |
a799883d PP |
511 | m.data = NULL; |
512 | m.size = 0; | |
513 | ||
cf0c6164 | 514 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
515 | return DEFER; |
516 | ||
517 | if (!exp_tls_dhparam) | |
518 | { | |
519 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
520 | m.data = US std_dh_prime_default(); | |
521 | m.size = Ustrlen(m.data); | |
522 | } | |
523 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
524 | use_file_in_spool = TRUE; | |
525 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
526 | { | |
527 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
528 | return OK; | |
529 | } | |
530 | else if (exp_tls_dhparam[0] != '/') | |
531 | { | |
f5d25c2b | 532 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
cf0c6164 | 533 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); |
a799883d PP |
534 | m.size = Ustrlen(m.data); |
535 | } | |
536 | else | |
537 | { | |
538 | use_fixed_file = TRUE; | |
539 | filename = exp_tls_dhparam; | |
540 | } | |
541 | ||
542 | if (m.data) | |
543 | { | |
544 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
545 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
546 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
547 | return OK; | |
548 | } | |
549 | ||
af3498d6 PP |
550 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
551 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
552 | different filename and ensure we have sufficient bits. */ |
553 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
554 | if (!dh_bits) | |
cf0c6164 | 555 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 556 | DEBUG(D_tls) |
b34fc30c | 557 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
558 | dh_bits); |
559 | #else | |
560 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
561 | DEBUG(D_tls) | |
562 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
563 | dh_bits); | |
564 | #endif | |
059ec3d9 | 565 | |
3375e053 PP |
566 | /* Some clients have hard-coded limits. */ |
567 | if (dh_bits > tls_dh_max_bits) | |
568 | { | |
569 | DEBUG(D_tls) | |
570 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
571 | tls_dh_max_bits); | |
572 | dh_bits = tls_dh_max_bits; | |
573 | } | |
574 | ||
a799883d PP |
575 | if (use_file_in_spool) |
576 | { | |
577 | if (!string_format(filename_buf, sizeof(filename_buf), | |
578 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 579 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
580 | filename = filename_buf; |
581 | } | |
059ec3d9 | 582 | |
b5aea5e1 | 583 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 584 | parameters. */ |
059ec3d9 | 585 | |
f5d25c2b | 586 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 587 | { |
b5aea5e1 | 588 | struct stat statbuf; |
17c76198 PP |
589 | FILE *fp; |
590 | int saved_errno; | |
591 | ||
592 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
593 | { | |
594 | saved_errno = errno; | |
595 | (void)close(fd); | |
cf0c6164 | 596 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
597 | } |
598 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
599 | { |
600 | (void)close(fd); | |
cf0c6164 | 601 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 602 | } |
40c90bca | 603 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
604 | { |
605 | saved_errno = errno; | |
606 | (void)close(fd); | |
607 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
cf0c6164 | 608 | strerror(saved_errno), NULL, errstr); |
b5aea5e1 | 609 | } |
059ec3d9 | 610 | |
b5aea5e1 | 611 | m.size = statbuf.st_size; |
40c90bca | 612 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
613 | { |
614 | fclose(fp); | |
cf0c6164 | 615 | return tls_error(US"malloc failed", strerror(errno), NULL, errstr); |
17c76198 | 616 | } |
40c90bca | 617 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
618 | { |
619 | saved_errno = errno; | |
620 | fclose(fp); | |
621 | free(m.data); | |
cf0c6164 | 622 | return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
623 | } |
624 | fclose(fp); | |
b5aea5e1 | 625 | |
17c76198 | 626 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 627 | free(m.data); |
17c76198 PP |
628 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
629 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
630 | } |
631 | ||
632 | /* If the file does not exist, fall through to compute new data and cache it. | |
633 | If there was any other opening error, it is serious. */ | |
634 | ||
182ad5cf PH |
635 | else if (errno == ENOENT) |
636 | { | |
17c76198 | 637 | rc = -1; |
182ad5cf | 638 | DEBUG(D_tls) |
17c76198 | 639 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
640 | } |
641 | else | |
17c76198 | 642 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 643 | NULL, NULL, errstr); |
b5aea5e1 PH |
644 | |
645 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
646 | is not useful. One particular case of this is when upgrading from an older | |
647 | release of Exim in which the data was stored in a different format. We don't | |
648 | try to be clever and support both formats; we just regenerate new data in this | |
649 | case. */ | |
650 | ||
17c76198 | 651 | if (rc < 0) |
b5aea5e1 | 652 | { |
17c76198 | 653 | uschar *temp_fn; |
201f5254 | 654 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 655 | |
17c76198 PP |
656 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
657 | return tls_error(US"Filename too long to generate replacement", | |
cf0c6164 | 658 | CS filename, NULL, errstr); |
059ec3d9 | 659 | |
17c76198 | 660 | temp_fn = string_copy(US "%s.XXXXXXX"); |
f5d25c2b | 661 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
cf0c6164 | 662 | return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); |
059ec3d9 PH |
663 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
664 | ||
201f5254 PP |
665 | /* GnuTLS overshoots! |
666 | * If we ask for 2236, we might get 2237 or more. | |
667 | * But there's no way to ask GnuTLS how many bits there really are. | |
668 | * We can ask how many bits were used in a TLS session, but that's it! | |
669 | * The prime itself is hidden behind too much abstraction. | |
670 | * So we ask for less, and proceed on a wing and a prayer. | |
671 | * First attempt, subtracted 3 for 2233 and got 2240. | |
672 | */ | |
cae6e576 | 673 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
674 | { |
675 | dh_bits_gen = dh_bits - 10; | |
676 | DEBUG(D_tls) | |
677 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
678 | dh_bits_gen); | |
679 | } | |
680 | ||
681 | DEBUG(D_tls) | |
682 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
683 | dh_bits_gen); | |
684 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
685 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
686 | ||
687 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
688 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
689 | sample apps handle this. */ | |
690 | ||
691 | sz = 0; | |
692 | m.data = NULL; | |
693 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
694 | m.data, &sz); | |
695 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
696 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
697 | m.size = sz; | |
40c90bca | 698 | if (!(m.data = malloc(m.size))) |
cf0c6164 | 699 | return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); |
40c90bca | 700 | |
1f00591e | 701 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 702 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 703 | m.data, &sz); |
17c76198 PP |
704 | if (rc != GNUTLS_E_SUCCESS) |
705 | { | |
706 | free(m.data); | |
707 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
708 | } | |
1f00591e | 709 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 710 | |
f5d25c2b | 711 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 PP |
712 | { |
713 | free(m.data); | |
714 | return tls_error(US"TLS cache write D-H params failed", | |
cf0c6164 | 715 | strerror(errno), NULL, errstr); |
17c76198 | 716 | } |
b5aea5e1 | 717 | free(m.data); |
f5d25c2b | 718 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
17c76198 | 719 | return tls_error(US"TLS cache write D-H params final newline failed", |
cf0c6164 | 720 | strerror(errno), NULL, errstr); |
17c76198 | 721 | |
f5d25c2b | 722 | if ((rc = close(fd))) |
cf0c6164 | 723 | return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); |
059ec3d9 | 724 | |
17c76198 PP |
725 | if (Urename(temp_fn, filename) < 0) |
726 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
cf0c6164 | 727 | temp_fn, filename), strerror(errno), NULL, errstr); |
059ec3d9 | 728 | |
17c76198 | 729 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
730 | } |
731 | ||
17c76198 | 732 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
733 | return OK; |
734 | } | |
735 | ||
736 | ||
737 | ||
738 | ||
23bb6982 JH |
739 | /* Create and install a selfsigned certificate, for use in server mode */ |
740 | ||
741 | static int | |
cf0c6164 | 742 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
743 | { |
744 | gnutls_x509_crt_t cert = NULL; | |
745 | time_t now; | |
746 | gnutls_x509_privkey_t pkey = NULL; | |
747 | const uschar * where; | |
748 | int rc; | |
749 | ||
750 | where = US"initialising pkey"; | |
751 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
752 | ||
753 | where = US"initialising cert"; | |
754 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
755 | ||
756 | where = US"generating pkey"; | |
757 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 758 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
23bb6982 | 759 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), |
76075bb5 JH |
760 | #else |
761 | 1024, | |
762 | #endif | |
763 | 0))) | |
23bb6982 JH |
764 | goto err; |
765 | ||
766 | where = US"configuring cert"; | |
767 | now = 0; | |
768 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) | |
769 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
770 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
771 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
772 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
773 | ||
774 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
775 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
776 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
777 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
778 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
779 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
780 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
781 | ) | |
782 | goto err; | |
783 | ||
784 | where = US"signing cert"; | |
785 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
786 | ||
787 | where = US"installing selfsign cert"; | |
788 | /* Since: 2.4.0 */ | |
789 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
790 | goto err; | |
791 | ||
792 | rc = OK; | |
793 | ||
794 | out: | |
795 | if (cert) gnutls_x509_crt_deinit(cert); | |
796 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
797 | return rc; | |
798 | ||
799 | err: | |
cf0c6164 | 800 | rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); |
23bb6982 JH |
801 | goto out; |
802 | } | |
803 | ||
804 | ||
805 | ||
806 | ||
059ec3d9 | 807 | /************************************************* |
17c76198 | 808 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
809 | *************************************************/ |
810 | ||
17c76198 PP |
811 | /* Called from both server and client code, via tls_init(), and also from |
812 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
813 | ||
814 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
815 | ||
816 | The callback should not call us unless state->trigger_sni_changes is true, | |
817 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
818 | |
819 | Arguments: | |
17c76198 | 820 | state exim_gnutls_state_st * |
cf0c6164 | 821 | errstr error string pointer |
059ec3d9 PH |
822 | |
823 | Returns: OK/DEFER/FAIL | |
824 | */ | |
825 | ||
826 | static int | |
cf0c6164 | 827 | tls_expand_session_files(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 828 | { |
1365611d | 829 | struct stat statbuf; |
059ec3d9 | 830 | int rc; |
17c76198 PP |
831 | const host_item *host = state->host; /* macro should be reconsidered? */ |
832 | uschar *saved_tls_certificate = NULL; | |
833 | uschar *saved_tls_privatekey = NULL; | |
834 | uschar *saved_tls_verify_certificates = NULL; | |
835 | uschar *saved_tls_crl = NULL; | |
836 | int cert_count; | |
837 | ||
838 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 839 | if (!host) /* server */ |
17c76198 PP |
840 | if (!state->received_sni) |
841 | { | |
d9b2312b JH |
842 | if (state->tls_certificate && |
843 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
844 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
845 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
846 | )) | |
17c76198 PP |
847 | { |
848 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
849 | state->trigger_sni_changes = TRUE; | |
850 | } | |
851 | } | |
852 | else | |
853 | { | |
1365611d | 854 | /* useful for debugging */ |
17c76198 PP |
855 | saved_tls_certificate = state->exp_tls_certificate; |
856 | saved_tls_privatekey = state->exp_tls_privatekey; | |
857 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
858 | saved_tls_crl = state->exp_tls_crl; | |
859 | } | |
059ec3d9 | 860 | |
1365611d PP |
861 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
862 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
863 | ||
17c76198 PP |
864 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
865 | state members, assuming consistent naming; and expand_check() returns | |
866 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 867 | |
17c76198 PP |
868 | /* check if we at least have a certificate, before doing expensive |
869 | D-H generation. */ | |
059ec3d9 | 870 | |
cf0c6164 | 871 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 872 | return DEFER; |
059ec3d9 | 873 | |
17c76198 | 874 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 875 | |
23bb6982 JH |
876 | if ( !state->exp_tls_certificate |
877 | || !*state->exp_tls_certificate | |
878 | ) | |
2b4a568d | 879 | if (!host) |
cf0c6164 | 880 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
881 | else |
882 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 883 | |
cf0c6164 | 884 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
885 | return DEFER; |
886 | ||
17c76198 PP |
887 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
888 | ||
889 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 890 | { |
17c76198 PP |
891 | state->tls_privatekey = state->tls_certificate; |
892 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 893 | } |
c91535f3 | 894 | |
059ec3d9 | 895 | |
17c76198 | 896 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
897 | { |
898 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
899 | state->exp_tls_certificate, state->exp_tls_privatekey); |
900 | ||
901 | if (state->received_sni) | |
23bb6982 JH |
902 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
903 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
904 | ) | |
17c76198 | 905 | { |
b34fc30c | 906 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
907 | } |
908 | else | |
909 | { | |
b34fc30c | 910 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 911 | } |
059ec3d9 | 912 | |
1365611d PP |
913 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
914 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
915 | GNUTLS_X509_FMT_PEM); | |
916 | exim_gnutls_err_check( | |
917 | string_sprintf("cert/key setup: cert=%s key=%s", | |
918 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
919 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 920 | } /* tls_certificate */ |
059ec3d9 | 921 | |
2b4a568d JH |
922 | |
923 | /* Set the OCSP stapling server info */ | |
924 | ||
f2de3a33 | 925 | #ifndef DISABLE_OCSP |
2b4a568d JH |
926 | if ( !host /* server */ |
927 | && tls_ocsp_file | |
928 | ) | |
929 | { | |
9196d5bf JH |
930 | if (gnutls_buggy_ocsp) |
931 | { | |
932 | DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
933 | } | |
934 | else | |
935 | { | |
936 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", | |
cf0c6164 | 937 | &state->exp_tls_ocsp_file, errstr)) |
9196d5bf | 938 | return DEFER; |
2b4a568d | 939 | |
9196d5bf JH |
940 | /* Use the full callback method for stapling just to get observability. |
941 | More efficient would be to read the file once only, if it never changed | |
942 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
44662487 | 943 | |
9196d5bf JH |
944 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, |
945 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 946 | |
9196d5bf JH |
947 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file); |
948 | } | |
2b4a568d JH |
949 | } |
950 | #endif | |
951 | ||
952 | ||
059ec3d9 PH |
953 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
954 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
955 | error message is provided. However, if we just refrain from setting anything up | |
956 | in that case, certificate verification fails, which seems to be the correct | |
957 | behaviour. */ | |
958 | ||
610ff438 | 959 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 960 | { |
cf0c6164 | 961 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 962 | return DEFER; |
610ff438 JH |
963 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
964 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
965 | state->exp_tls_verify_certificates = NULL; | |
966 | #endif | |
17c76198 | 967 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 968 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 969 | return DEFER; |
059ec3d9 | 970 | |
1365611d PP |
971 | if (!(state->exp_tls_verify_certificates && |
972 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
973 | { |
974 | DEBUG(D_tls) | |
1365611d PP |
975 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
976 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 977 | return OK; |
b34fc30c | 978 | } |
1365611d | 979 | } |
83e2f8a2 PP |
980 | else |
981 | { | |
982 | DEBUG(D_tls) | |
983 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
984 | return OK; | |
985 | } | |
17c76198 | 986 | |
cb1d7830 JH |
987 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
988 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
989 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
990 | else | |
991 | #endif | |
1365611d | 992 | { |
cb1d7830 JH |
993 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
994 | { | |
995 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
996 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
997 | strerror(errno)); | |
998 | return DEFER; | |
999 | } | |
17c76198 | 1000 | |
a7fec7a7 | 1001 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1002 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1003 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1004 | other weirdness. The thing we really want to check is that it's not a | |
1005 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1006 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1007 | if (S_ISDIR(statbuf.st_mode)) |
1008 | { | |
1009 | DEBUG(D_tls) | |
1010 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1011 | state->exp_tls_verify_certificates); | |
1012 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1013 | "tls_verify_certificates \"%s\" is a directory", | |
1014 | state->exp_tls_verify_certificates); | |
1015 | return DEFER; | |
1016 | } | |
a7fec7a7 | 1017 | #endif |
059ec3d9 | 1018 | |
cb1d7830 JH |
1019 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1020 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1021 | |
cb1d7830 JH |
1022 | if (statbuf.st_size == 0) |
1023 | { | |
1024 | DEBUG(D_tls) | |
1025 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1026 | return OK; | |
1027 | } | |
059ec3d9 | 1028 | |
cb1d7830 | 1029 | cert_count = |
a7fec7a7 JH |
1030 | |
1031 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1032 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1033 | ? | |
1034 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1035 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1036 | : | |
a7fec7a7 | 1037 | #endif |
cb1d7830 JH |
1038 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1039 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1040 | } | |
a7fec7a7 | 1041 | |
1365611d PP |
1042 | if (cert_count < 0) |
1043 | { | |
1044 | rc = cert_count; | |
cb1d7830 | 1045 | exim_gnutls_err_check(US"setting certificate trust"); |
1365611d PP |
1046 | } |
1047 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1048 | |
5c8cda3a PP |
1049 | if (state->tls_crl && *state->tls_crl && |
1050 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1051 | { |
5c8cda3a PP |
1052 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1053 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1054 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1055 | if (cert_count < 0) | |
1365611d | 1056 | { |
5c8cda3a | 1057 | rc = cert_count; |
1365611d PP |
1058 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
1059 | } | |
5c8cda3a | 1060 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1061 | } |
059ec3d9 | 1062 | |
059ec3d9 PH |
1063 | return OK; |
1064 | } | |
1065 | ||
1066 | ||
1067 | ||
1068 | ||
1365611d PP |
1069 | /************************************************* |
1070 | * Set X.509 state variables * | |
1071 | *************************************************/ | |
1072 | ||
1073 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1074 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1075 | structure. Which means various other non-re-expanded pieces of state | |
1076 | need to be re-set in the new struct, so the setting logic is pulled | |
1077 | out to this. | |
1078 | ||
1079 | Arguments: | |
1080 | state exim_gnutls_state_st * | |
cf0c6164 | 1081 | errstr error string pointer |
1365611d PP |
1082 | |
1083 | Returns: OK/DEFER/FAIL | |
1084 | */ | |
1085 | ||
1086 | static int | |
cf0c6164 | 1087 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1088 | { |
1089 | int rc; | |
1090 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1091 | ||
1092 | /* Create D-H parameters, or read them from the cache file. This function does | |
1093 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1094 | client-side params. */ | |
1095 | ||
1096 | if (!state->host) | |
1097 | { | |
1098 | if (!dh_server_params) | |
1099 | { | |
cf0c6164 | 1100 | rc = init_server_dh(errstr); |
1365611d PP |
1101 | if (rc != OK) return rc; |
1102 | } | |
1103 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1104 | } | |
1105 | ||
1106 | /* Link the credentials to the session. */ | |
1107 | ||
1108 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
1109 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
1110 | ||
1111 | return OK; | |
1112 | } | |
1113 | ||
059ec3d9 | 1114 | /************************************************* |
17c76198 | 1115 | * Initialize for GnuTLS * |
059ec3d9 PH |
1116 | *************************************************/ |
1117 | ||
9196d5bf | 1118 | |
4fb7df6d JH |
1119 | #ifndef DISABLE_OCSP |
1120 | ||
9196d5bf JH |
1121 | static BOOL |
1122 | tls_is_buggy_ocsp(void) | |
1123 | { | |
1124 | const uschar * s; | |
1125 | uschar maj, mid, mic; | |
1126 | ||
1127 | s = CUS gnutls_check_version(NULL); | |
1128 | maj = atoi(CCS s); | |
1129 | if (maj == 3) | |
1130 | { | |
1131 | while (*s && *s != '.') s++; | |
1132 | mid = atoi(CCS ++s); | |
1133 | if (mid <= 2) | |
1134 | return TRUE; | |
1135 | else if (mid >= 5) | |
1136 | return FALSE; | |
1137 | else | |
1138 | { | |
1139 | while (*s && *s != '.') s++; | |
1140 | mic = atoi(CCS ++s); | |
1141 | return mic <= (mid == 3 ? 16 : 3); | |
1142 | } | |
1143 | } | |
1144 | return FALSE; | |
1145 | } | |
1146 | ||
4fb7df6d | 1147 | #endif |
9196d5bf JH |
1148 | |
1149 | ||
17c76198 PP |
1150 | /* Called from both server and client code. In the case of a server, errors |
1151 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1152 | |
1153 | Arguments: | |
17c76198 PP |
1154 | host connected host, if client; NULL if server |
1155 | certificate certificate file | |
1156 | privatekey private key file | |
1157 | sni TLS SNI to send, sometimes when client; else NULL | |
1158 | cas CA certs file | |
1159 | crl CRL file | |
1160 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1161 | caller_state returned state-info structure |
cf0c6164 | 1162 | errstr error string pointer |
059ec3d9 | 1163 | |
17c76198 | 1164 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1165 | */ |
1166 | ||
17c76198 PP |
1167 | static int |
1168 | tls_init( | |
1169 | const host_item *host, | |
1170 | const uschar *certificate, | |
1171 | const uschar *privatekey, | |
1172 | const uschar *sni, | |
1173 | const uschar *cas, | |
1174 | const uschar *crl, | |
1175 | const uschar *require_ciphers, | |
cf0c6164 JH |
1176 | exim_gnutls_state_st **caller_state, |
1177 | uschar ** errstr) | |
059ec3d9 | 1178 | { |
17c76198 PP |
1179 | exim_gnutls_state_st *state; |
1180 | int rc; | |
1181 | size_t sz; | |
1182 | const char *errpos; | |
1183 | uschar *p; | |
1184 | BOOL want_default_priorities; | |
1185 | ||
1186 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1187 | { |
17c76198 PP |
1188 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1189 | ||
a5f239e4 PP |
1190 | #ifdef HAVE_GNUTLS_PKCS11 |
1191 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1192 | which loads modules from a config file, which sounds good and may be wanted | |
1193 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1194 | environment variables are used and so breaks for users calling mailq. | |
1195 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1196 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1197 | { |
1198 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1199 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1200 | } | |
1201 | #endif | |
1202 | ||
17c76198 PP |
1203 | rc = gnutls_global_init(); |
1204 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1205 | ||
1206 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1207 | DEBUG(D_tls) | |
059ec3d9 | 1208 | { |
17c76198 PP |
1209 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1210 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1211 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1212 | } |
17c76198 PP |
1213 | #endif |
1214 | ||
4fb7df6d JH |
1215 | #ifndef DISABLE_OCSP |
1216 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1217 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1218 | #endif |
9196d5bf | 1219 | |
17c76198 | 1220 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1221 | } |
059ec3d9 | 1222 | |
17c76198 PP |
1223 | if (host) |
1224 | { | |
1225 | state = &state_client; | |
1226 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1227 | state->tlsp = &tls_out; |
17c76198 PP |
1228 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1229 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1230 | } | |
1231 | else | |
1232 | { | |
1233 | state = &state_server; | |
1234 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1235 | state->tlsp = &tls_in; |
17c76198 PP |
1236 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1237 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1238 | } | |
1239 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1240 | |
17c76198 | 1241 | state->host = host; |
059ec3d9 | 1242 | |
17c76198 PP |
1243 | state->tls_certificate = certificate; |
1244 | state->tls_privatekey = privatekey; | |
5779e6aa | 1245 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1246 | state->tls_sni = sni; |
1247 | state->tls_verify_certificates = cas; | |
1248 | state->tls_crl = crl; | |
059ec3d9 | 1249 | |
17c76198 PP |
1250 | /* This handles the variables that might get re-expanded after TLS SNI; |
1251 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1252 | |
17c76198 PP |
1253 | DEBUG(D_tls) |
1254 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1255 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1256 | |
1365611d PP |
1257 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1258 | requires a new structure afterwards. */ | |
83da1223 | 1259 | |
cf0c6164 | 1260 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1261 | |
17c76198 PP |
1262 | /* set SNI in client, only */ |
1263 | if (host) | |
1264 | { | |
cf0c6164 | 1265 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1266 | return DEFER; |
0df4ab80 | 1267 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1268 | { |
1269 | DEBUG(D_tls) | |
0df4ab80 JH |
1270 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1271 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1272 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1273 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
17c76198 PP |
1274 | exim_gnutls_err_check(US"gnutls_server_name_set"); |
1275 | } | |
1276 | } | |
1277 | else if (state->tls_sni) | |
1278 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1279 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1280 | |
17c76198 | 1281 | /* This is the priority string support, |
42bfef1e | 1282 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1283 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1284 | This was backwards incompatible, but means Exim no longer needs to track | |
1285 | all algorithms and provide string forms for them. */ | |
83da1223 | 1286 | |
17c76198 | 1287 | want_default_priorities = TRUE; |
83da1223 | 1288 | |
17c76198 | 1289 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1290 | { |
cf0c6164 | 1291 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1292 | return DEFER; |
1293 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1294 | { |
17c76198 PP |
1295 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1296 | state->exp_tls_require_ciphers); | |
1297 | ||
1298 | rc = gnutls_priority_init(&state->priority_cache, | |
1299 | CS state->exp_tls_require_ciphers, &errpos); | |
1300 | want_default_priorities = FALSE; | |
1301 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1302 | } |
1303 | } | |
17c76198 PP |
1304 | if (want_default_priorities) |
1305 | { | |
83e2f8a2 PP |
1306 | DEBUG(D_tls) |
1307 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1308 | exim_default_gnutls_priority); | |
17c76198 PP |
1309 | rc = gnutls_priority_init(&state->priority_cache, |
1310 | exim_default_gnutls_priority, &errpos); | |
1311 | p = US exim_default_gnutls_priority; | |
1312 | } | |
83da1223 | 1313 | |
17c76198 PP |
1314 | exim_gnutls_err_check(string_sprintf( |
1315 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1316 | p, errpos - CS p, errpos)); | |
1317 | ||
1318 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1319 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1320 | ||
1321 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1322 | ||
1323 | /* Reduce security in favour of increased compatibility, if the admin | |
1324 | decides to make that trade-off. */ | |
1325 | if (gnutls_compat_mode) | |
83da1223 | 1326 | { |
17c76198 PP |
1327 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1328 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1329 | gnutls_session_enable_compatibility_mode(state->session); | |
1330 | #else | |
1331 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1332 | #endif | |
83da1223 PH |
1333 | } |
1334 | ||
17c76198 | 1335 | *caller_state = state; |
17c76198 | 1336 | return OK; |
83da1223 PH |
1337 | } |
1338 | ||
1339 | ||
1340 | ||
059ec3d9 | 1341 | /************************************************* |
17c76198 | 1342 | * Extract peer information * |
059ec3d9 PH |
1343 | *************************************************/ |
1344 | ||
17c76198 | 1345 | /* Called from both server and client code. |
4fe99a6c PP |
1346 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1347 | and we use that to detect double-calls. | |
059ec3d9 | 1348 | |
75fe387d PP |
1349 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1350 | for logging in the server side, but for the client side, we log after teardown | |
1351 | in src/deliver.c. While the session is up, we can twist about states and | |
1352 | repoint tls_* globals, but those variables used for logging or other variable | |
1353 | expansion that happens _after_ delivery need to have a longer life-time. | |
1354 | ||
1355 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1356 | doing this more than once per generation of a state context. We set them in | |
1357 | the state context, and repoint tls_* to them. After the state goes away, the | |
1358 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1359 | ||
1360 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1361 | don't apply. | |
1362 | ||
059ec3d9 | 1363 | Arguments: |
17c76198 | 1364 | state exim_gnutls_state_st * |
cf0c6164 | 1365 | errstr pointer to error string |
059ec3d9 | 1366 | |
17c76198 | 1367 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1368 | */ |
1369 | ||
17c76198 | 1370 | static int |
cf0c6164 | 1371 | peer_status(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 1372 | { |
75fe387d | 1373 | uschar cipherbuf[256]; |
27f19eb4 | 1374 | const gnutls_datum_t *cert_list; |
75fe387d | 1375 | int old_pool, rc; |
17c76198 | 1376 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1377 | gnutls_protocol_t protocol; |
1378 | gnutls_cipher_algorithm_t cipher; | |
1379 | gnutls_kx_algorithm_t kx; | |
1380 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1381 | gnutls_certificate_type_t ct; |
1382 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1383 | uschar *p, *dn_buf; |
17c76198 | 1384 | size_t sz; |
059ec3d9 | 1385 | |
4fe99a6c | 1386 | if (state->have_set_peerdn) |
17c76198 | 1387 | return OK; |
4fe99a6c | 1388 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1389 | |
4fe99a6c | 1390 | state->peerdn = NULL; |
059ec3d9 | 1391 | |
4fe99a6c PP |
1392 | /* tls_cipher */ |
1393 | cipher = gnutls_cipher_get(state->session); | |
1394 | protocol = gnutls_protocol_get_version(state->session); | |
1395 | mac = gnutls_mac_get(state->session); | |
1396 | kx = gnutls_kx_get(state->session); | |
1397 | ||
75fe387d | 1398 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1399 | "%s:%s:%d", |
1400 | gnutls_protocol_get_name(protocol), | |
1401 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1402 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1403 | ||
1404 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1405 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1406 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1407 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1408 | if (isspace(*p)) |
1409 | *p = '-'; | |
75fe387d PP |
1410 | old_pool = store_pool; |
1411 | store_pool = POOL_PERM; | |
1412 | state->ciphersuite = string_copy(cipherbuf); | |
1413 | store_pool = old_pool; | |
817d9f57 | 1414 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1415 | |
1416 | /* tls_peerdn */ | |
17c76198 | 1417 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1418 | |
17c76198 PP |
1419 | if (cert_list == NULL || cert_list_size == 0) |
1420 | { | |
17c76198 PP |
1421 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1422 | cert_list, cert_list_size); | |
e51c7be2 | 1423 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1424 | return tls_error(US"certificate verification failed", |
cf0c6164 | 1425 | "no certificate received from peer", state->host, errstr); |
17c76198 PP |
1426 | return OK; |
1427 | } | |
059ec3d9 | 1428 | |
17c76198 PP |
1429 | ct = gnutls_certificate_type_get(state->session); |
1430 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1431 | { |
17c76198 | 1432 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1433 | DEBUG(D_tls) |
1434 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1435 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1436 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1437 | ctn, state->host, errstr); |
17c76198 | 1438 | return OK; |
83da1223 | 1439 | } |
059ec3d9 | 1440 | |
e51c7be2 JH |
1441 | #define exim_gnutls_peer_err(Label) \ |
1442 | do { \ | |
1443 | if (rc != GNUTLS_E_SUCCESS) \ | |
1444 | { \ | |
1445 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1446 | (Label), gnutls_strerror(rc)); \ | |
1447 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
cf0c6164 | 1448 | return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ |
e51c7be2 JH |
1449 | return OK; \ |
1450 | } \ | |
1451 | } while (0) | |
17c76198 | 1452 | |
9d1c15ef JH |
1453 | rc = import_cert(&cert_list[0], &crt); |
1454 | exim_gnutls_peer_err(US"cert 0"); | |
1455 | ||
1456 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1457 | |
17c76198 PP |
1458 | sz = 0; |
1459 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1460 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1461 | { |
17c76198 PP |
1462 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1463 | return FAIL; /* should not happen */ | |
059ec3d9 | 1464 | } |
17c76198 PP |
1465 | dn_buf = store_get_perm(sz); |
1466 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1467 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1468 | |
17c76198 PP |
1469 | state->peerdn = dn_buf; |
1470 | ||
1471 | return OK; | |
1472 | #undef exim_gnutls_peer_err | |
1473 | } | |
059ec3d9 | 1474 | |
059ec3d9 | 1475 | |
059ec3d9 | 1476 | |
059ec3d9 | 1477 | |
17c76198 PP |
1478 | /************************************************* |
1479 | * Verify peer certificate * | |
1480 | *************************************************/ | |
059ec3d9 | 1481 | |
17c76198 PP |
1482 | /* Called from both server and client code. |
1483 | *Should* be using a callback registered with | |
1484 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1485 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1486 | |
17c76198 PP |
1487 | Arguments: |
1488 | state exim_gnutls_state_st * | |
cf0c6164 | 1489 | errstr where to put an error message |
059ec3d9 | 1490 | |
17c76198 PP |
1491 | Returns: |
1492 | FALSE if the session should be rejected | |
1493 | TRUE if the cert is okay or we just don't care | |
1494 | */ | |
059ec3d9 | 1495 | |
17c76198 | 1496 | static BOOL |
cf0c6164 | 1497 | verify_certificate(exim_gnutls_state_st *state, uschar ** errstr) |
17c76198 PP |
1498 | { |
1499 | int rc; | |
1500 | unsigned int verify; | |
1501 | ||
cf0c6164 | 1502 | *errstr = NULL; |
17c76198 | 1503 | |
cf0c6164 | 1504 | if ((rc = peer_status(state, errstr)) != OK) |
e6060e2c | 1505 | { |
17c76198 | 1506 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1507 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1508 | } |
1509 | else | |
17c76198 | 1510 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1511 | |
17c76198 PP |
1512 | /* Handle the result of verification. INVALID seems to be set as well |
1513 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1514 | |
e51c7be2 JH |
1515 | if (rc < 0 || |
1516 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1517 | ) | |
17c76198 PP |
1518 | { |
1519 | state->peer_cert_verified = FALSE; | |
cf0c6164 JH |
1520 | if (!*errstr) |
1521 | *errstr = verify & GNUTLS_CERT_REVOKED | |
1522 | ? US"certificate revoked" : US"certificate invalid"; | |
059ec3d9 | 1523 | |
17c76198 | 1524 | DEBUG(D_tls) |
e51c7be2 | 1525 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1526 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1527 | |
e51c7be2 | 1528 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1529 | { |
e51c7be2 JH |
1530 | gnutls_alert_send(state->session, |
1531 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1532 | return FALSE; |
1533 | } | |
1534 | DEBUG(D_tls) | |
4789da3a | 1535 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1536 | } |
e51c7be2 | 1537 | |
17c76198 PP |
1538 | else |
1539 | { | |
aa2a70ba | 1540 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1541 | { |
1542 | int sep = 0; | |
55414b25 | 1543 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 | 1544 | uschar * name; |
76075bb5 | 1545 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) |
e51c7be2 JH |
1546 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) |
1547 | break; | |
1548 | if (!name) | |
1549 | { | |
1550 | DEBUG(D_tls) | |
1551 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba JH |
1552 | if (state->verify_requirement >= VERIFY_REQUIRED) |
1553 | { | |
1554 | gnutls_alert_send(state->session, | |
1555 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1556 | return FALSE; | |
1557 | } | |
1558 | return TRUE; | |
e51c7be2 JH |
1559 | } |
1560 | } | |
17c76198 | 1561 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1562 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1563 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1564 | } |
059ec3d9 | 1565 | |
817d9f57 | 1566 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1567 | |
17c76198 PP |
1568 | return TRUE; |
1569 | } | |
059ec3d9 | 1570 | |
17c76198 PP |
1571 | |
1572 | ||
1573 | ||
1574 | /* ------------------------------------------------------------------------ */ | |
1575 | /* Callbacks */ | |
1576 | ||
1577 | /* Logging function which can be registered with | |
1578 | * gnutls_global_set_log_function() | |
1579 | * gnutls_global_set_log_level() 0..9 | |
1580 | */ | |
af3498d6 | 1581 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1582 | static void |
17c76198 | 1583 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1584 | { |
8c79eebf PP |
1585 | size_t len = strlen(message); |
1586 | if (len < 1) | |
1587 | { | |
1588 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1589 | return; | |
1590 | } | |
1591 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1592 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1593 | } |
af3498d6 | 1594 | #endif |
059ec3d9 | 1595 | |
059ec3d9 | 1596 | |
17c76198 PP |
1597 | /* Called after client hello, should handle SNI work. |
1598 | This will always set tls_sni (state->received_sni) if available, | |
1599 | and may trigger presenting different certificates, | |
1600 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1601 | |
17c76198 PP |
1602 | Should be registered with |
1603 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1604 | |
17c76198 PP |
1605 | "This callback must return 0 on success or a gnutls error code to terminate the |
1606 | handshake.". | |
059ec3d9 | 1607 | |
17c76198 PP |
1608 | For inability to get SNI information, we return 0. |
1609 | We only return non-zero if re-setup failed. | |
817d9f57 | 1610 | Only used for server-side TLS. |
17c76198 | 1611 | */ |
44bbabb5 | 1612 | |
17c76198 PP |
1613 | static int |
1614 | exim_sni_handling_cb(gnutls_session_t session) | |
1615 | { | |
1616 | char sni_name[MAX_HOST_LEN]; | |
1617 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1618 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1619 | unsigned int sni_type; |
1620 | int rc, old_pool; | |
cf0c6164 | 1621 | uschar * dummy_errstr; |
17c76198 PP |
1622 | |
1623 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1624 | if (rc != GNUTLS_E_SUCCESS) |
1625 | { | |
1626 | DEBUG(D_tls) { | |
1627 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1628 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1629 | else | |
1630 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1631 | gnutls_strerror(rc), rc); | |
cf0c6164 | 1632 | } |
b34fc30c PP |
1633 | return 0; |
1634 | } | |
1635 | ||
17c76198 PP |
1636 | if (sni_type != GNUTLS_NAME_DNS) |
1637 | { | |
1638 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1639 | return 0; | |
1640 | } | |
44bbabb5 | 1641 | |
17c76198 PP |
1642 | /* We now have a UTF-8 string in sni_name */ |
1643 | old_pool = store_pool; | |
1644 | store_pool = POOL_PERM; | |
1645 | state->received_sni = string_copyn(US sni_name, data_len); | |
1646 | store_pool = old_pool; | |
1647 | ||
1648 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1649 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1650 | |
1651 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1652 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1653 | ||
1654 | if (!state->trigger_sni_changes) | |
1655 | return 0; | |
1656 | ||
cf0c6164 | 1657 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
1658 | { |
1659 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1660 | been offered. The best we can do now is abort. */ | |
1661 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1662 | } | |
1663 | ||
cf0c6164 | 1664 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
1665 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
1666 | ||
1667 | return 0; | |
059ec3d9 PH |
1668 | } |
1669 | ||
1670 | ||
1671 | ||
f2de3a33 | 1672 | #ifndef DISABLE_OCSP |
44662487 JH |
1673 | |
1674 | static int | |
1675 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1676 | gnutls_datum_t * ocsp_response) | |
1677 | { | |
1678 | int ret; | |
1679 | ||
44662487 JH |
1680 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1681 | { | |
1682 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
5903c6ff | 1683 | CS ptr); |
018058b2 | 1684 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1685 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1686 | } | |
1687 | ||
018058b2 | 1688 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1689 | return 0; |
1690 | } | |
1691 | ||
1692 | #endif | |
1693 | ||
1694 | ||
0cbf2b82 | 1695 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1696 | /* |
1697 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1698 | for an exim TLS connection (either direction), raising a tls:cert event |
1699 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1700 | can deny verification. |
1701 | ||
1702 | Return 0 for the handshake to continue or non-zero to terminate. | |
1703 | */ | |
1704 | ||
1705 | static int | |
723fe533 | 1706 | verify_cb(gnutls_session_t session) |
a7538db1 | 1707 | { |
27f19eb4 | 1708 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1709 | unsigned int cert_list_size = 0; |
1710 | gnutls_x509_crt_t crt; | |
1711 | int rc; | |
b30275b8 | 1712 | uschar * yield; |
a7538db1 JH |
1713 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1714 | ||
1715 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1716 | if (cert_list) | |
1717 | while (cert_list_size--) | |
1718 | { | |
1719 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1720 | if (rc != GNUTLS_E_SUCCESS) | |
1721 | { | |
1722 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1723 | cert_list_size, gnutls_strerror(rc)); | |
1724 | break; | |
1725 | } | |
1726 | ||
1727 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1728 | if ((yield = event_raise(state->event_action, |
1729 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1730 | { |
1731 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1732 | "SSL verify denied by event-action: depth=%d: %s", |
1733 | cert_list_size, yield); | |
a7538db1 JH |
1734 | return 1; /* reject */ |
1735 | } | |
1736 | state->tlsp->peercert = NULL; | |
1737 | } | |
1738 | ||
1739 | return 0; | |
1740 | } | |
1741 | ||
1742 | #endif | |
44662487 JH |
1743 | |
1744 | ||
17c76198 PP |
1745 | |
1746 | /* ------------------------------------------------------------------------ */ | |
1747 | /* Exported functions */ | |
1748 | ||
1749 | ||
1750 | ||
1751 | ||
059ec3d9 PH |
1752 | /************************************************* |
1753 | * Start a TLS session in a server * | |
1754 | *************************************************/ | |
1755 | ||
1756 | /* This is called when Exim is running as a server, after having received | |
1757 | the STARTTLS command. It must respond to that command, and then negotiate | |
1758 | a TLS session. | |
1759 | ||
1760 | Arguments: | |
83da1223 | 1761 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 1762 | errstr pointer to error string |
059ec3d9 PH |
1763 | |
1764 | Returns: OK on success | |
1765 | DEFER for errors before the start of the negotiation | |
4c04137d | 1766 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
1767 | continue running. |
1768 | */ | |
1769 | ||
1770 | int | |
cf0c6164 | 1771 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
1772 | { |
1773 | int rc; | |
cf0c6164 | 1774 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
1775 | |
1776 | /* Check for previous activation */ | |
817d9f57 | 1777 | if (tls_in.active >= 0) |
059ec3d9 | 1778 | { |
cf0c6164 | 1779 | tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); |
925ac8e4 | 1780 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
1781 | return FAIL; |
1782 | } | |
1783 | ||
1784 | /* Initialize the library. If it fails, it will already have logged the error | |
1785 | and sent an SMTP response. */ | |
1786 | ||
17c76198 | 1787 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1788 | |
cf0c6164 | 1789 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 1790 | NULL, tls_verify_certificates, tls_crl, |
cf0c6164 | 1791 | require_ciphers, &state, errstr)) != OK) return rc; |
059ec3d9 | 1792 | |
059ec3d9 PH |
1793 | /* If this is a host for which certificate verification is mandatory or |
1794 | optional, set up appropriately. */ | |
1795 | ||
059ec3d9 | 1796 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1797 | { |
e51c7be2 JH |
1798 | DEBUG(D_tls) |
1799 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1800 | state->verify_requirement = VERIFY_REQUIRED; |
1801 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1802 | } | |
059ec3d9 | 1803 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1804 | { |
e51c7be2 JH |
1805 | DEBUG(D_tls) |
1806 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1807 | state->verify_requirement = VERIFY_OPTIONAL; |
1808 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1809 | } | |
1810 | else | |
1811 | { | |
e51c7be2 JH |
1812 | DEBUG(D_tls) |
1813 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1814 | state->verify_requirement = VERIFY_NONE; |
1815 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1816 | } | |
059ec3d9 | 1817 | |
0cbf2b82 | 1818 | #ifndef DISABLE_EVENT |
723fe533 JH |
1819 | if (event_action) |
1820 | { | |
1821 | state->event_action = event_action; | |
1822 | gnutls_session_set_ptr(state->session, state); | |
1823 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
1824 | } | |
1825 | #endif | |
1826 | ||
17c76198 PP |
1827 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1828 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1829 | |
17c76198 PP |
1830 | gnutls_handshake_set_post_client_hello_function(state->session, |
1831 | exim_sni_handling_cb); | |
059ec3d9 PH |
1832 | |
1833 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1834 | on connection, where outputting anything now upsets the clients and tends to | |
1835 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1836 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1837 | mode, the fflush() happens when smtp_getc() is called. */ | |
1838 | ||
817d9f57 | 1839 | if (!state->tlsp->on_connect) |
059ec3d9 | 1840 | { |
925ac8e4 | 1841 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 1842 | fflush(smtp_out); |
059ec3d9 PH |
1843 | } |
1844 | ||
1845 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1846 | that the GnuTLS library doesn't. */ | |
1847 | ||
17c76198 | 1848 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
1849 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
1850 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
1851 | state->fd_in = fileno(smtp_in); |
1852 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1853 | |
1854 | sigalrm_seen = FALSE; | |
1855 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1856 | do |
17c76198 | 1857 | rc = gnutls_handshake(state->session); |
157a7880 | 1858 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
1859 | alarm(0); |
1860 | ||
17c76198 | 1861 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1862 | { |
059ec3d9 PH |
1863 | /* It seems that, except in the case of a timeout, we have to close the |
1864 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1865 | until the server times out. */ | |
1866 | ||
60d10ce7 | 1867 | if (sigalrm_seen) |
ad7fc6eb | 1868 | { |
cf0c6164 | 1869 | tls_error(US"gnutls_handshake", "timed out", NULL, errstr); |
ad7fc6eb JH |
1870 | gnutls_db_remove_session(state->session); |
1871 | } | |
60d10ce7 | 1872 | else |
059ec3d9 | 1873 | { |
cf0c6164 | 1874 | tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); |
f5d25c2b | 1875 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 1876 | gnutls_deinit(state->session); |
ed62aae3 | 1877 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 1878 | millisleep(500); |
ad7fc6eb | 1879 | shutdown(state->fd_out, SHUT_WR); |
60d10ce7 | 1880 | for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ |
f1e894f3 PH |
1881 | (void)fclose(smtp_out); |
1882 | (void)fclose(smtp_in); | |
60d10ce7 | 1883 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
1884 | } |
1885 | ||
1886 | return FAIL; | |
1887 | } | |
1888 | ||
1889 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1890 | ||
17c76198 PP |
1891 | /* Verify after the fact */ |
1892 | ||
9d1c15ef | 1893 | if ( state->verify_requirement != VERIFY_NONE |
cf0c6164 | 1894 | && !verify_certificate(state, errstr)) |
059ec3d9 | 1895 | { |
9d1c15ef | 1896 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1897 | { |
cf0c6164 | 1898 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 1899 | return FAIL; |
17c76198 | 1900 | } |
9d1c15ef JH |
1901 | DEBUG(D_tls) |
1902 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 1903 | *errstr); |
059ec3d9 PH |
1904 | } |
1905 | ||
17c76198 PP |
1906 | /* Figure out peer DN, and if authenticated, etc. */ |
1907 | ||
cf0c6164 | 1908 | if ((rc = peer_status(state, NULL)) != OK) return rc; |
17c76198 PP |
1909 | |
1910 | /* Sets various Exim expansion variables; always safe within server */ | |
1911 | ||
9d1c15ef | 1912 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1913 | |
1914 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1915 | and initialize appropriately. */ | |
1916 | ||
17c76198 | 1917 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1918 | |
1919 | receive_getc = tls_getc; | |
0d81dabc | 1920 | receive_getbuf = tls_getbuf; |
584e96c6 | 1921 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
1922 | receive_ungetc = tls_ungetc; |
1923 | receive_feof = tls_feof; | |
1924 | receive_ferror = tls_ferror; | |
58eb016e | 1925 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1926 | |
059ec3d9 PH |
1927 | return OK; |
1928 | } | |
1929 | ||
1930 | ||
1931 | ||
1932 | ||
aa2a70ba JH |
1933 | static void |
1934 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
1935 | smtp_transport_options_block * ob) | |
1936 | { | |
5130845b | 1937 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 1938 | { |
4af0d74a | 1939 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 1940 | #ifdef SUPPORT_I18N |
4af0d74a JH |
1941 | string_domain_utf8_to_alabel(host->name, NULL); |
1942 | #else | |
1943 | host->name; | |
1944 | #endif | |
aa2a70ba JH |
1945 | DEBUG(D_tls) |
1946 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
1947 | state->exp_tls_verify_cert_hostnames); | |
1948 | } | |
1949 | } | |
aa2a70ba JH |
1950 | |
1951 | ||
059ec3d9 PH |
1952 | /************************************************* |
1953 | * Start a TLS session in a client * | |
1954 | *************************************************/ | |
1955 | ||
1956 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1957 | ||
1958 | Arguments: | |
1959 | fd the fd of the connection | |
1960 | host connected host (for messages) | |
83da1223 | 1961 | addr the first address (not used) |
a7538db1 | 1962 | tb transport (always smtp) |
059ec3d9 | 1963 | |
cf0c6164 JH |
1964 | errstr error string pointer |
1965 | ||
059ec3d9 PH |
1966 | Returns: OK/DEFER/FAIL (because using common functions), |
1967 | but for a client, DEFER and FAIL have the same meaning | |
1968 | */ | |
1969 | ||
1970 | int | |
17c76198 | 1971 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1972 | address_item *addr ARG_UNUSED, |
cf0c6164 | 1973 | transport_instance * tb, |
0e66b3b6 | 1974 | #ifdef EXPERIMENTAL_DANE |
cf0c6164 | 1975 | dns_answer * tlsa_dnsa ARG_UNUSED, |
0e66b3b6 | 1976 | #endif |
cf0c6164 | 1977 | uschar ** errstr) |
059ec3d9 | 1978 | { |
a7538db1 JH |
1979 | smtp_transport_options_block *ob = |
1980 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 1981 | int rc; |
17c76198 | 1982 | exim_gnutls_state_st *state = NULL; |
f2de3a33 | 1983 | #ifndef DISABLE_OCSP |
5130845b JH |
1984 | BOOL require_ocsp = |
1985 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 1986 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 1987 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 1988 | #endif |
059ec3d9 | 1989 | |
17c76198 | 1990 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1991 | |
65867078 JH |
1992 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
1993 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
cf0c6164 | 1994 | ob->tls_require_ciphers, &state, errstr)) != OK) |
2b4a568d | 1995 | return rc; |
059ec3d9 | 1996 | |
54c90be1 | 1997 | { |
65867078 JH |
1998 | int dh_min_bits = ob->tls_dh_min_bits; |
1999 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2000 | { | |
2001 | DEBUG(D_tls) | |
2002 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2003 | " clamping %d up to %d\n", | |
2004 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2005 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2006 | } | |
54c90be1 | 2007 | |
65867078 JH |
2008 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2009 | " acceptable bits to %d\n", | |
2010 | dh_min_bits); | |
2011 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2012 | } | |
83da1223 | 2013 | |
94431adb | 2014 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2015 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2016 | the specified host patterns if one of them is defined */ | |
2017 | ||
aa2a70ba JH |
2018 | if ( ( state->exp_tls_verify_certificates |
2019 | && !ob->tls_verify_hosts | |
610ff438 | 2020 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) |
aa2a70ba | 2021 | ) |
5130845b | 2022 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK |
2b4a568d | 2023 | ) |
17c76198 | 2024 | { |
aa2a70ba | 2025 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2026 | DEBUG(D_tls) |
2027 | debug_printf("TLS: server certificate verification required.\n"); | |
2028 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2029 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2030 | } | |
5130845b | 2031 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2032 | { |
aa2a70ba | 2033 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2034 | DEBUG(D_tls) |
2035 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2036 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2037 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2038 | } | |
2039 | else | |
2040 | { | |
e51c7be2 JH |
2041 | DEBUG(D_tls) |
2042 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2043 | state->verify_requirement = VERIFY_NONE; |
2044 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2045 | } |
059ec3d9 | 2046 | |
f2de3a33 JH |
2047 | #ifndef DISABLE_OCSP |
2048 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2049 | if (request_ocsp) |
9d1c15ef JH |
2050 | { |
2051 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2052 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2053 | NULL, 0, NULL)) != OK) | |
9d1c15ef | 2054 | return tls_error(US"cert-status-req", |
cf0c6164 | 2055 | gnutls_strerror(rc), state->host, errstr); |
44662487 | 2056 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2057 | } |
2b4a568d JH |
2058 | #endif |
2059 | ||
0cbf2b82 | 2060 | #ifndef DISABLE_EVENT |
774ef2d7 | 2061 | if (tb->event_action) |
a7538db1 | 2062 | { |
774ef2d7 | 2063 | state->event_action = tb->event_action; |
a7538db1 | 2064 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2065 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2066 | } |
2067 | #endif | |
2068 | ||
27f19eb4 | 2069 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2070 | state->fd_in = fd; |
2071 | state->fd_out = fd; | |
059ec3d9 | 2072 | |
9d1c15ef | 2073 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2074 | /* There doesn't seem to be a built-in timeout on connection. */ |
2075 | ||
2076 | sigalrm_seen = FALSE; | |
65867078 | 2077 | alarm(ob->command_timeout); |
17c76198 PP |
2078 | do |
2079 | { | |
2080 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
2081 | } while ((rc == GNUTLS_E_AGAIN) || |
2082 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
2083 | alarm(0); |
2084 | ||
4fe99a6c | 2085 | if (rc != GNUTLS_E_SUCCESS) |
60d10ce7 JH |
2086 | if (sigalrm_seen) |
2087 | { | |
2088 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
cf0c6164 | 2089 | return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); |
60d10ce7 JH |
2090 | } |
2091 | else | |
cf0c6164 | 2092 | return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); |
4fe99a6c | 2093 | |
17c76198 | 2094 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2095 | |
17c76198 | 2096 | /* Verify late */ |
059ec3d9 | 2097 | |
17c76198 | 2098 | if (state->verify_requirement != VERIFY_NONE && |
cf0c6164 JH |
2099 | !verify_certificate(state, errstr)) |
2100 | return tls_error(US"certificate verification failed", *errstr, state->host, errstr); | |
059ec3d9 | 2101 | |
f2de3a33 | 2102 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2103 | if (require_ocsp) |
2104 | { | |
2105 | DEBUG(D_tls) | |
2106 | { | |
2107 | gnutls_datum_t stapling; | |
2108 | gnutls_ocsp_resp_t resp; | |
2109 | gnutls_datum_t printed; | |
2110 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2111 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2112 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2113 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2114 | ) | |
2115 | { | |
65867078 | 2116 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2117 | gnutls_free(printed.data); |
2118 | } | |
2119 | else | |
cf0c6164 | 2120 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host, errstr); |
2b4a568d JH |
2121 | } |
2122 | ||
2b4a568d | 2123 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2124 | { |
2125 | tls_out.ocsp = OCSP_FAILED; | |
cf0c6164 | 2126 | return tls_error(US"certificate status check failed", NULL, state->host, errstr); |
018058b2 | 2127 | } |
2b4a568d | 2128 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2129 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2130 | } |
2131 | #endif | |
2132 | ||
17c76198 | 2133 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2134 | |
cf0c6164 | 2135 | if ((rc = peer_status(state, errstr)) != OK) |
2b4a568d | 2136 | return rc; |
059ec3d9 | 2137 | |
4fe99a6c | 2138 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2139 | |
9d1c15ef | 2140 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2141 | |
059ec3d9 PH |
2142 | return OK; |
2143 | } | |
2144 | ||
2145 | ||
2146 | ||
17c76198 | 2147 | |
059ec3d9 | 2148 | /************************************************* |
17c76198 | 2149 | * Close down a TLS session * |
059ec3d9 PH |
2150 | *************************************************/ |
2151 | ||
17c76198 PP |
2152 | /* This is also called from within a delivery subprocess forked from the |
2153 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2154 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2155 | |
17c76198 PP |
2156 | Arguments: TRUE if gnutls_bye is to be called |
2157 | Returns: nothing | |
059ec3d9 PH |
2158 | */ |
2159 | ||
17c76198 | 2160 | void |
817d9f57 | 2161 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2162 | { |
817d9f57 | 2163 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2164 | |
389ca47a | 2165 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2166 | |
2167 | if (shutdown) | |
2168 | { | |
f5723109 | 2169 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); |
17c76198 PP |
2170 | gnutls_bye(state->session, GNUTLS_SHUT_WR); |
2171 | } | |
2172 | ||
2173 | gnutls_deinit(state->session); | |
ed62aae3 HSHR |
2174 | gnutls_certificate_free_credentials(state->x509_cred); |
2175 | ||
17c76198 | 2176 | |
389ca47a | 2177 | state->tlsp->active = -1; |
17c76198 PP |
2178 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2179 | ||
2180 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2181 | { | |
2182 | gnutls_global_deinit(); | |
2183 | exim_gnutls_base_init_done = FALSE; | |
2184 | } | |
059ec3d9 PH |
2185 | } |
2186 | ||
2187 | ||
2188 | ||
17c76198 | 2189 | |
0d81dabc JH |
2190 | static BOOL |
2191 | tls_refill(unsigned lim) | |
2192 | { | |
2193 | exim_gnutls_state_st * state = &state_server; | |
2194 | ssize_t inbytes; | |
2195 | ||
2196 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2197 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2198 | ||
2199 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
2200 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2201 | MIN(ssl_xfer_buffer_size, lim)); | |
2202 | alarm(0); | |
2203 | ||
2204 | /* Timeouts do not get this far; see command_timeout_handler(). | |
2205 | A zero-byte return appears to mean that the TLS session has been | |
2206 | closed down, not that the socket itself has been closed down. Revert to | |
2207 | non-TLS handling. */ | |
2208 | ||
2209 | if (sigalrm_seen) | |
2210 | { | |
2211 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
2212 | state->xfer_error = 1; | |
2213 | return FALSE; | |
2214 | } | |
2215 | ||
2216 | else if (inbytes == 0) | |
2217 | { | |
2218 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2219 | ||
2220 | receive_getc = smtp_getc; | |
2221 | receive_getbuf = smtp_getbuf; | |
2222 | receive_get_cache = smtp_get_cache; | |
2223 | receive_ungetc = smtp_ungetc; | |
2224 | receive_feof = smtp_feof; | |
2225 | receive_ferror = smtp_ferror; | |
2226 | receive_smtp_buffered = smtp_buffered; | |
2227 | ||
2228 | gnutls_deinit(state->session); | |
2229 | gnutls_certificate_free_credentials(state->x509_cred); | |
2230 | ||
2231 | state->session = NULL; | |
2232 | state->tlsp->active = -1; | |
2233 | state->tlsp->bits = 0; | |
2234 | state->tlsp->certificate_verified = FALSE; | |
2235 | tls_channelbinding_b64 = NULL; | |
2236 | state->tlsp->cipher = NULL; | |
2237 | state->tlsp->peercert = NULL; | |
2238 | state->tlsp->peerdn = NULL; | |
2239 | ||
2240 | return FALSE; | |
2241 | } | |
2242 | ||
2243 | /* Handle genuine errors */ | |
2244 | ||
2245 | else if (inbytes < 0) | |
2246 | { | |
2247 | record_io_error(state, (int) inbytes, US"recv", NULL); | |
2248 | state->xfer_error = 1; | |
2249 | return FALSE; | |
2250 | } | |
2251 | #ifndef DISABLE_DKIM | |
2252 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
2253 | #endif | |
2254 | state->xfer_buffer_hwm = (int) inbytes; | |
2255 | state->xfer_buffer_lwm = 0; | |
2256 | return TRUE; | |
2257 | } | |
2258 | ||
059ec3d9 PH |
2259 | /************************************************* |
2260 | * TLS version of getc * | |
2261 | *************************************************/ | |
2262 | ||
2263 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2264 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2265 | Only used by the server-side TLS. |
059ec3d9 | 2266 | |
17c76198 PP |
2267 | This feeds DKIM and should be used for all message-body reads. |
2268 | ||
bd8fbe36 | 2269 | Arguments: lim Maximum amount to read/bufffer |
059ec3d9 PH |
2270 | Returns: the next character or EOF |
2271 | */ | |
2272 | ||
2273 | int | |
bd8fbe36 | 2274 | tls_getc(unsigned lim) |
059ec3d9 | 2275 | { |
0d81dabc | 2276 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 2277 | |
0d81dabc JH |
2278 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2279 | if (!tls_refill(lim)) | |
2280 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 2281 | |
0d81dabc | 2282 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2283 | |
0d81dabc JH |
2284 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
2285 | } | |
059ec3d9 | 2286 | |
0d81dabc JH |
2287 | uschar * |
2288 | tls_getbuf(unsigned * len) | |
2289 | { | |
2290 | exim_gnutls_state_st * state = &state_server; | |
2291 | unsigned size; | |
2292 | uschar * buf; | |
059ec3d9 | 2293 | |
0d81dabc JH |
2294 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2295 | if (!tls_refill(*len)) | |
059ec3d9 | 2296 | { |
0d81dabc JH |
2297 | if (!state->xfer_error) return smtp_getbuf(len); |
2298 | *len = 0; | |
2299 | return NULL; | |
059ec3d9 | 2300 | } |
059ec3d9 | 2301 | |
0d81dabc JH |
2302 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
2303 | size = *len; | |
2304 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
2305 | state->xfer_buffer_lwm += size; | |
2306 | *len = size; | |
2307 | return buf; | |
059ec3d9 PH |
2308 | } |
2309 | ||
0d81dabc | 2310 | |
584e96c6 JH |
2311 | void |
2312 | tls_get_cache() | |
2313 | { | |
9960d1e5 | 2314 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2315 | exim_gnutls_state_st * state = &state_server; |
2316 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2317 | if (n > 0) | |
2318 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2319 | #endif |
9960d1e5 | 2320 | } |
584e96c6 | 2321 | |
059ec3d9 | 2322 | |
925ac8e4 JH |
2323 | BOOL |
2324 | tls_could_read(void) | |
2325 | { | |
2326 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
2327 | || gnutls_record_check_pending(state_server.session) > 0; | |
2328 | } | |
2329 | ||
2330 | ||
059ec3d9 | 2331 | |
17c76198 | 2332 | |
059ec3d9 PH |
2333 | /************************************************* |
2334 | * Read bytes from TLS channel * | |
2335 | *************************************************/ | |
2336 | ||
17c76198 PP |
2337 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2338 | then the caller must feed DKIM. | |
817d9f57 | 2339 | |
059ec3d9 PH |
2340 | Arguments: |
2341 | buff buffer of data | |
2342 | len size of buffer | |
2343 | ||
2344 | Returns: the number of bytes read | |
2345 | -1 after a failed read | |
2346 | */ | |
2347 | ||
2348 | int | |
817d9f57 | 2349 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2350 | { |
817d9f57 | 2351 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2352 | ssize_t inbytes; |
059ec3d9 | 2353 | |
17c76198 PP |
2354 | if (len > INT_MAX) |
2355 | len = INT_MAX; | |
059ec3d9 | 2356 | |
17c76198 PP |
2357 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2358 | DEBUG(D_tls) | |
2359 | debug_printf("*** PROBABLY A BUG *** " \ | |
2360 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2361 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2362 | ||
2363 | DEBUG(D_tls) | |
2364 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2365 | state->session, buff, len); | |
2366 | ||
2367 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2368 | if (inbytes > 0) return inbytes; |
2369 | if (inbytes == 0) | |
2370 | { | |
2371 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2372 | } | |
17c76198 | 2373 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2374 | |
2375 | return -1; | |
2376 | } | |
2377 | ||
2378 | ||
2379 | ||
17c76198 | 2380 | |
059ec3d9 PH |
2381 | /************************************************* |
2382 | * Write bytes down TLS channel * | |
2383 | *************************************************/ | |
2384 | ||
2385 | /* | |
2386 | Arguments: | |
817d9f57 | 2387 | is_server channel specifier |
059ec3d9 PH |
2388 | buff buffer of data |
2389 | len number of bytes | |
925ac8e4 | 2390 | more more data expected soon |
059ec3d9 PH |
2391 | |
2392 | Returns: the number of bytes after a successful write, | |
2393 | -1 after a failed write | |
2394 | */ | |
2395 | ||
2396 | int | |
925ac8e4 | 2397 | tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2398 | { |
17c76198 PP |
2399 | ssize_t outbytes; |
2400 | size_t left = len; | |
817d9f57 | 2401 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
925ac8e4 JH |
2402 | #ifdef SUPPORT_CORK |
2403 | static BOOL corked = FALSE; | |
2404 | ||
2405 | if (more && !corked) gnutls_record_cork(state->session); | |
2406 | #endif | |
2407 | ||
2408 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
2409 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 2410 | |
059ec3d9 PH |
2411 | while (left > 0) |
2412 | { | |
17c76198 PP |
2413 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2414 | buff, left); | |
2415 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2416 | |
17c76198 | 2417 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2418 | if (outbytes < 0) |
2419 | { | |
17c76198 | 2420 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2421 | return -1; |
2422 | } | |
2423 | if (outbytes == 0) | |
2424 | { | |
17c76198 | 2425 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2426 | return -1; |
2427 | } | |
2428 | ||
2429 | left -= outbytes; | |
2430 | buff += outbytes; | |
2431 | } | |
2432 | ||
17c76198 PP |
2433 | if (len > INT_MAX) |
2434 | { | |
2435 | DEBUG(D_tls) | |
2436 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2437 | len); | |
2438 | len = INT_MAX; | |
2439 | } | |
2440 | ||
925ac8e4 JH |
2441 | #ifdef SUPPORT_CORK |
2442 | if (more != corked) | |
2443 | { | |
2444 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
2445 | corked = more; | |
2446 | } | |
2447 | #endif | |
2448 | ||
17c76198 | 2449 | return (int) len; |
059ec3d9 PH |
2450 | } |
2451 | ||
2452 | ||
2453 | ||
17c76198 | 2454 | |
059ec3d9 | 2455 | /************************************************* |
17c76198 | 2456 | * Random number generation * |
059ec3d9 PH |
2457 | *************************************************/ |
2458 | ||
17c76198 PP |
2459 | /* Pseudo-random number generation. The result is not expected to be |
2460 | cryptographically strong but not so weak that someone will shoot themselves | |
2461 | in the foot using it as a nonce in input in some email header scheme or | |
2462 | whatever weirdness they'll twist this into. The result should handle fork() | |
2463 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2464 | |
17c76198 PP |
2465 | Arguments: |
2466 | max range maximum | |
2467 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2468 | */ |
2469 | ||
af3498d6 | 2470 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2471 | int |
2472 | vaguely_random_number(int max) | |
059ec3d9 | 2473 | { |
17c76198 PP |
2474 | unsigned int r; |
2475 | int i, needed_len; | |
2476 | uschar *p; | |
2477 | uschar smallbuf[sizeof(r)]; | |
2478 | ||
2479 | if (max <= 1) | |
2480 | return 0; | |
2481 | ||
2482 | needed_len = sizeof(r); | |
2483 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2484 | * asked for a number less than 10. */ | |
2485 | for (r = max, i = 0; r; ++i) | |
2486 | r >>= 1; | |
2487 | i = (i + 7) / 8; | |
2488 | if (i < needed_len) | |
2489 | needed_len = i; | |
2490 | ||
2491 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2492 | if (i < 0) | |
059ec3d9 | 2493 | { |
17c76198 PP |
2494 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2495 | return vaguely_random_number_fallback(max); | |
2496 | } | |
2497 | r = 0; | |
2498 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2499 | { | |
2500 | r *= 256; | |
2501 | r += *p; | |
059ec3d9 PH |
2502 | } |
2503 | ||
17c76198 PP |
2504 | /* We don't particularly care about weighted results; if someone wants |
2505 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2506 | return r % max; | |
059ec3d9 | 2507 | } |
af3498d6 PP |
2508 | #else /* HAVE_GNUTLS_RND */ |
2509 | int | |
2510 | vaguely_random_number(int max) | |
2511 | { | |
2512 | return vaguely_random_number_fallback(max); | |
2513 | } | |
2514 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2515 | |
36f12725 NM |
2516 | |
2517 | ||
2518 | ||
3375e053 PP |
2519 | /************************************************* |
2520 | * Let tls_require_ciphers be checked at startup * | |
2521 | *************************************************/ | |
2522 | ||
2523 | /* The tls_require_ciphers option, if set, must be something which the | |
2524 | library can parse. | |
2525 | ||
2526 | Returns: NULL on success, or error message | |
2527 | */ | |
2528 | ||
2529 | uschar * | |
2530 | tls_validate_require_cipher(void) | |
2531 | { | |
2532 | int rc; | |
2533 | uschar *expciphers = NULL; | |
2534 | gnutls_priority_t priority_cache; | |
2535 | const char *errpos; | |
cf0c6164 | 2536 | uschar * dummy_errstr; |
3375e053 PP |
2537 | |
2538 | #define validate_check_rc(Label) do { \ | |
2539 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2540 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2541 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2542 | ||
2543 | if (exim_gnutls_base_init_done) | |
2544 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2545 | "already initialised GnuTLS, Exim developer bug"); | |
2546 | ||
a5f239e4 | 2547 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2548 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2549 | { |
2550 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2551 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2552 | } | |
2553 | #endif | |
3375e053 PP |
2554 | rc = gnutls_global_init(); |
2555 | validate_check_rc(US"gnutls_global_init()"); | |
2556 | exim_gnutls_base_init_done = TRUE; | |
2557 | ||
2558 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2559 | return_deinit(NULL); | |
2560 | ||
cf0c6164 JH |
2561 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
2562 | &dummy_errstr)) | |
3375e053 PP |
2563 | return_deinit(US"failed to expand tls_require_ciphers"); |
2564 | ||
2565 | if (!(expciphers && *expciphers)) | |
2566 | return_deinit(NULL); | |
2567 | ||
2568 | DEBUG(D_tls) | |
2569 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2570 | ||
2571 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2572 | validate_check_rc(string_sprintf( | |
2573 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2574 | expciphers, errpos - CS expciphers, errpos)); | |
2575 | ||
2576 | #undef return_deinit | |
2577 | #undef validate_check_rc | |
2578 | gnutls_global_deinit(); | |
2579 | ||
2580 | return NULL; | |
2581 | } | |
2582 | ||
2583 | ||
2584 | ||
2585 | ||
36f12725 NM |
2586 | /************************************************* |
2587 | * Report the library versions. * | |
2588 | *************************************************/ | |
2589 | ||
2590 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2591 | ||
2592 | Arguments: a FILE* to print the results to | |
2593 | Returns: nothing | |
2594 | */ | |
2595 | ||
2596 | void | |
2597 | tls_version_report(FILE *f) | |
2598 | { | |
754a0503 PP |
2599 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2600 | " Runtime: %s\n", | |
2601 | LIBGNUTLS_VERSION, | |
2602 | gnutls_check_version(NULL)); | |
36f12725 NM |
2603 | } |
2604 | ||
2b4a568d JH |
2605 | /* vi: aw ai sw=2 |
2606 | */ | |
059ec3d9 | 2607 | /* End of tls-gnu.c */ |