Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
f9ba5e22 | 5 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
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 | |
47195144 JH |
66 | #if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP) |
67 | # define SUPPORT_SRV_OCSP_STACK | |
68 | #endif | |
899b8bbc JH |
69 | #if GNUTLS_VERSION_NUMBER >= 0x030000 && defined(EXPERIMENTAL_DANE) |
70 | # define SUPPORT_DANE | |
94c13285 JH |
71 | # define DANESSL_USAGE_DANE_TA 2 |
72 | # define DANESSL_USAGE_DANE_EE 3 | |
73 | #endif | |
74 | #if GNUTLS_VERSION_NUMBER < 0x999999 && defined(EXPERIMENTAL_DANE) | |
75 | # define GNUTLS_BROKEN_DANE_VALIDATION | |
899b8bbc | 76 | #endif |
7e07527a | 77 | |
f2de3a33 | 78 | #ifndef DISABLE_OCSP |
2b4a568d JH |
79 | # include <gnutls/ocsp.h> |
80 | #endif | |
899b8bbc JH |
81 | #ifdef SUPPORT_DANE |
82 | # include <gnutls/dane.h> | |
83 | #endif | |
059ec3d9 | 84 | |
17c76198 | 85 | /* GnuTLS 2 vs 3 |
059ec3d9 | 86 | |
17c76198 PP |
87 | GnuTLS 3 only: |
88 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 89 | |
17c76198 PP |
90 | Changes: |
91 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
92 | */ | |
059ec3d9 | 93 | |
17c76198 | 94 | /* Local static variables for GnuTLS */ |
059ec3d9 | 95 | |
17c76198 | 96 | /* Values for verify_requirement */ |
059ec3d9 | 97 | |
e51c7be2 | 98 | enum peer_verify_requirement |
899b8bbc | 99 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED, VERIFY_DANE }; |
059ec3d9 | 100 | |
17c76198 PP |
101 | /* This holds most state for server or client; with this, we can set up an |
102 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
103 | over the TLS variables available for expansion. | |
059ec3d9 | 104 | |
17c76198 PP |
105 | Some of these correspond to variables in globals.c; those variables will |
106 | be set to point to content in one of these instances, as appropriate for | |
107 | the stage of the process lifetime. | |
059ec3d9 | 108 | |
389ca47a | 109 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 110 | */ |
059ec3d9 | 111 | |
17c76198 | 112 | typedef struct exim_gnutls_state { |
9d1c15ef | 113 | gnutls_session_t session; |
17c76198 | 114 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 115 | gnutls_priority_t priority_cache; |
17c76198 | 116 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
117 | int fd_in; |
118 | int fd_out; | |
119 | BOOL peer_cert_verified; | |
899b8bbc | 120 | BOOL peer_dane_verified; |
9d1c15ef JH |
121 | BOOL trigger_sni_changes; |
122 | BOOL have_set_peerdn; | |
17c76198 | 123 | const struct host_item *host; |
9d1c15ef JH |
124 | gnutls_x509_crt_t peercert; |
125 | uschar *peerdn; | |
126 | uschar *ciphersuite; | |
127 | uschar *received_sni; | |
17c76198 PP |
128 | |
129 | const uschar *tls_certificate; | |
130 | const uschar *tls_privatekey; | |
131 | const uschar *tls_sni; /* client send only, not received */ | |
132 | const uschar *tls_verify_certificates; | |
133 | const uschar *tls_crl; | |
134 | const uschar *tls_require_ciphers; | |
e51c7be2 | 135 | |
17c76198 PP |
136 | uschar *exp_tls_certificate; |
137 | uschar *exp_tls_privatekey; | |
17c76198 PP |
138 | uschar *exp_tls_verify_certificates; |
139 | uschar *exp_tls_crl; | |
140 | uschar *exp_tls_require_ciphers; | |
55414b25 | 141 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 142 | #ifndef DISABLE_EVENT |
a7538db1 JH |
143 | uschar *event_action; |
144 | #endif | |
899b8bbc JH |
145 | #ifdef SUPPORT_DANE |
146 | char * const * dane_data; | |
147 | const int * dane_data_len; | |
148 | #endif | |
17c76198 | 149 | |
389ca47a | 150 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 151 | |
17c76198 PP |
152 | uschar *xfer_buffer; |
153 | int xfer_buffer_lwm; | |
154 | int xfer_buffer_hwm; | |
155 | int xfer_eof; | |
156 | int xfer_error; | |
17c76198 PP |
157 | } exim_gnutls_state_st; |
158 | ||
159 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
f2ed27cf JH |
160 | .session = NULL, |
161 | .x509_cred = NULL, | |
162 | .priority_cache = NULL, | |
163 | .verify_requirement = VERIFY_NONE, | |
164 | .fd_in = -1, | |
165 | .fd_out = -1, | |
166 | .peer_cert_verified = FALSE, | |
899b8bbc | 167 | .peer_dane_verified = FALSE, |
f2ed27cf JH |
168 | .trigger_sni_changes =FALSE, |
169 | .have_set_peerdn = FALSE, | |
170 | .host = NULL, | |
171 | .peercert = NULL, | |
172 | .peerdn = NULL, | |
173 | .ciphersuite = NULL, | |
174 | .received_sni = NULL, | |
175 | ||
176 | .tls_certificate = NULL, | |
177 | .tls_privatekey = NULL, | |
178 | .tls_sni = NULL, | |
179 | .tls_verify_certificates = NULL, | |
180 | .tls_crl = NULL, | |
181 | .tls_require_ciphers =NULL, | |
182 | ||
183 | .exp_tls_certificate = NULL, | |
184 | .exp_tls_privatekey = NULL, | |
185 | .exp_tls_verify_certificates = NULL, | |
186 | .exp_tls_crl = NULL, | |
187 | .exp_tls_require_ciphers = NULL, | |
f2ed27cf | 188 | .exp_tls_verify_cert_hostnames = NULL, |
0cbf2b82 | 189 | #ifndef DISABLE_EVENT |
f2ed27cf | 190 | .event_action = NULL, |
e51c7be2 | 191 | #endif |
f2ed27cf JH |
192 | .tlsp = NULL, |
193 | ||
194 | .xfer_buffer = NULL, | |
195 | .xfer_buffer_lwm = 0, | |
196 | .xfer_buffer_hwm = 0, | |
197 | .xfer_eof = 0, | |
198 | .xfer_error = 0, | |
17c76198 | 199 | }; |
83da1223 | 200 | |
17c76198 PP |
201 | /* Not only do we have our own APIs which don't pass around state, assuming |
202 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
203 | for callbacks, or as part of the session, so we have to keep a "this is the | |
204 | context we're currently dealing with" pointer and rely upon being | |
205 | single-threaded to keep from processing data on an inbound TLS connection while | |
206 | talking to another TLS connection for an outbound check. This does mean that | |
207 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
208 | second connection. |
209 | XXX But see gnutls_session_get_ptr() | |
210 | */ | |
059ec3d9 | 211 | |
17c76198 | 212 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 213 | |
17c76198 PP |
214 | /* dh_params are initialised once within the lifetime of a process using TLS; |
215 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
216 | don't want to repeat this. */ | |
83da1223 | 217 | |
17c76198 | 218 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 219 | |
17c76198 | 220 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 221 | |
17c76198 | 222 | static const int ssl_session_timeout = 200; |
059ec3d9 | 223 | |
17c76198 | 224 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 225 | |
17c76198 | 226 | /* Guard library core initialisation */ |
83da1223 | 227 | |
17c76198 | 228 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 229 | |
4fb7df6d | 230 | #ifndef DISABLE_OCSP |
9196d5bf | 231 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 232 | #endif |
9196d5bf | 233 | |
059ec3d9 | 234 | |
17c76198 PP |
235 | /* ------------------------------------------------------------------------ */ |
236 | /* macros */ | |
83da1223 | 237 | |
17c76198 | 238 | #define MAX_HOST_LEN 255 |
83da1223 | 239 | |
17c76198 PP |
240 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
241 | the library logging; a value less than 0 disables the calls to set up logging | |
ef9da2ee JH |
242 | callbacks. Possibly GNuTLS also looks for an environment variable |
243 | "GNUTLS_DEBUG_LEVEL". */ | |
2c17bb02 | 244 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 245 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 246 | #endif |
83da1223 | 247 | |
2c17bb02 | 248 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 249 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 250 | #endif |
83da1223 | 251 | |
af3498d6 PP |
252 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
253 | can ask for a bit-strength. Without that, we stick to the constant we had | |
254 | before, for now. */ | |
2c17bb02 | 255 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 256 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 257 | #endif |
af3498d6 | 258 | |
47195144 JH |
259 | #define exim_gnutls_err_check(rc, Label) do { \ |
260 | if ((rc) != GNUTLS_E_SUCCESS) \ | |
cf0c6164 JH |
261 | return tls_error((Label), gnutls_strerror(rc), host, errstr); \ |
262 | } while (0) | |
059ec3d9 | 263 | |
cf0c6164 JH |
264 | #define expand_check_tlsvar(Varname, errstr) \ |
265 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 266 | |
17c76198 | 267 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
268 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
269 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
270 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
271 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
272 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
273 | * isn't available sometimes, so this needs to become a conditional | |
274 | * compilation; the sanest way to deal with this being a problem on | |
275 | * older OSes is to block it in the Local/Makefile with this compiler | |
276 | * definition */ | |
e51c7be2 JH |
277 | # ifndef AVOID_GNUTLS_PKCS11 |
278 | # define HAVE_GNUTLS_PKCS11 | |
279 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 280 | #endif |
83da1223 | 281 | |
af3498d6 PP |
282 | |
283 | ||
284 | ||
285 | /* ------------------------------------------------------------------------ */ | |
286 | /* Callback declarations */ | |
287 | ||
288 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
289 | static void exim_gnutls_logger_cb(int level, const char *message); | |
290 | #endif | |
291 | ||
292 | static int exim_sni_handling_cb(gnutls_session_t session); | |
293 | ||
f2de3a33 | 294 | #ifndef DISABLE_OCSP |
44662487 JH |
295 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
296 | gnutls_datum_t * ocsp_response); | |
297 | #endif | |
af3498d6 PP |
298 | |
299 | ||
300 | ||
17c76198 PP |
301 | /* ------------------------------------------------------------------------ */ |
302 | /* Static functions */ | |
059ec3d9 PH |
303 | |
304 | /************************************************* | |
305 | * Handle TLS error * | |
306 | *************************************************/ | |
307 | ||
308 | /* Called from lots of places when errors occur before actually starting to do | |
309 | the TLS handshake, that is, while the session is still in clear. Always returns | |
310 | DEFER for a server and FAIL for a client so that most calls can use "return | |
311 | tls_error(...)" to do this processing and then give an appropriate return. A | |
312 | single function is used for both server and client, because it is called from | |
313 | some shared functions. | |
314 | ||
315 | Argument: | |
316 | prefix text to include in the logged error | |
7199e1ee TF |
317 | msg additional error string (may be NULL) |
318 | usually obtained from gnutls_strerror() | |
17c76198 PP |
319 | host NULL if setting up a server; |
320 | the connected host if setting up a client | |
cf0c6164 | 321 | errstr pointer to returned error string |
059ec3d9 PH |
322 | |
323 | Returns: OK/DEFER/FAIL | |
324 | */ | |
325 | ||
326 | static int | |
cf0c6164 JH |
327 | tls_error(const uschar *prefix, const char *msg, const host_item *host, |
328 | uschar ** errstr) | |
059ec3d9 | 329 | { |
cf0c6164 JH |
330 | if (errstr) |
331 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); | |
332 | return host ? FAIL : DEFER; | |
059ec3d9 PH |
333 | } |
334 | ||
335 | ||
336 | ||
17c76198 | 337 | |
059ec3d9 | 338 | /************************************************* |
17c76198 | 339 | * Deal with logging errors during I/O * |
059ec3d9 PH |
340 | *************************************************/ |
341 | ||
17c76198 | 342 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 343 | |
17c76198 PP |
344 | Argument: |
345 | state the current GnuTLS exim state container | |
346 | rc the GnuTLS error code, or 0 if it's a local error | |
347 | when text identifying read or write | |
348 | text local error text when ec is 0 | |
059ec3d9 | 349 | |
17c76198 | 350 | Returns: nothing |
059ec3d9 PH |
351 | */ |
352 | ||
17c76198 PP |
353 | static void |
354 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 355 | { |
cf0c6164 JH |
356 | const char * msg; |
357 | uschar * errstr; | |
059ec3d9 | 358 | |
17c76198 PP |
359 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
360 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
361 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
362 | else | |
363 | msg = gnutls_strerror(rc); | |
059ec3d9 | 364 | |
cf0c6164 JH |
365 | (void) tls_error(when, msg, state->host, &errstr); |
366 | ||
367 | if (state->host) | |
368 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
369 | state->host->name, state->host->address, errstr); | |
370 | else | |
371 | { | |
372 | uschar * conn_info = smtp_get_connection_info(); | |
373 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
374 | /* I'd like to get separated H= here, but too hard for now */ | |
375 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
376 | } | |
17c76198 | 377 | } |
059ec3d9 | 378 | |
059ec3d9 | 379 | |
059ec3d9 | 380 | |
059ec3d9 | 381 | |
17c76198 PP |
382 | /************************************************* |
383 | * Set various Exim expansion vars * | |
384 | *************************************************/ | |
059ec3d9 | 385 | |
e51c7be2 JH |
386 | #define exim_gnutls_cert_err(Label) \ |
387 | do \ | |
388 | { \ | |
389 | if (rc != GNUTLS_E_SUCCESS) \ | |
390 | { \ | |
391 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
392 | (Label), gnutls_strerror(rc)); \ | |
393 | return rc; \ | |
394 | } \ | |
395 | } while (0) | |
9d1c15ef JH |
396 | |
397 | static int | |
27f19eb4 | 398 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
399 | { |
400 | int rc; | |
401 | ||
402 | rc = gnutls_x509_crt_init(crtp); | |
403 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
404 | ||
405 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
406 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
407 | ||
408 | return rc; | |
409 | } | |
410 | ||
411 | #undef exim_gnutls_cert_err | |
412 | ||
413 | ||
17c76198 PP |
414 | /* We set various Exim global variables from the state, once a session has |
415 | been established. With TLS callouts, may need to change this to stack | |
416 | variables, or just re-call it with the server state after client callout | |
417 | has finished. | |
059ec3d9 | 418 | |
9d1c15ef | 419 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
420 | |
421 | Sets: | |
422 | tls_active fd | |
423 | tls_bits strength indicator | |
424 | tls_certificate_verified bool indicator | |
425 | tls_channelbinding_b64 for some SASL mechanisms | |
426 | tls_cipher a string | |
9d1c15ef | 427 | tls_peercert pointer to library internal |
17c76198 PP |
428 | tls_peerdn a string |
429 | tls_sni a (UTF-8) string | |
9d1c15ef | 430 | tls_ourcert pointer to library internal |
17c76198 PP |
431 | |
432 | Argument: | |
433 | state the relevant exim_gnutls_state_st * | |
434 | */ | |
435 | ||
436 | static void | |
9d1c15ef | 437 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 438 | { |
17c76198 | 439 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
440 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
441 | int old_pool; | |
442 | int rc; | |
443 | gnutls_datum_t channel; | |
444 | #endif | |
9d1c15ef | 445 | tls_support * tlsp = state->tlsp; |
17c76198 | 446 | |
9d1c15ef | 447 | tlsp->active = state->fd_out; |
17c76198 PP |
448 | |
449 | cipher = gnutls_cipher_get(state->session); | |
450 | /* returns size in "bytes" */ | |
9d1c15ef | 451 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 452 | |
9d1c15ef | 453 | tlsp->cipher = state->ciphersuite; |
17c76198 | 454 | |
817d9f57 | 455 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 456 | |
9d1c15ef | 457 | tlsp->certificate_verified = state->peer_cert_verified; |
899b8bbc JH |
458 | #ifdef SUPPORT_DANE |
459 | tlsp->dane_verified = state->peer_dane_verified; | |
460 | #endif | |
059ec3d9 | 461 | |
17c76198 PP |
462 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
463 | only available for use for authenticators while this TLS session is running. */ | |
464 | ||
465 | tls_channelbinding_b64 = NULL; | |
466 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
467 | channel.data = NULL; | |
468 | channel.size = 0; | |
469 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
470 | if (rc) { | |
471 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
472 | } else { | |
473 | old_pool = store_pool; | |
474 | store_pool = POOL_PERM; | |
f4d091fb | 475 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
476 | store_pool = old_pool; |
477 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
478 | } | |
479 | #endif | |
480 | ||
9d1c15ef JH |
481 | /* peercert is set in peer_status() */ |
482 | tlsp->peerdn = state->peerdn; | |
483 | tlsp->sni = state->received_sni; | |
484 | ||
485 | /* record our certificate */ | |
486 | { | |
27f19eb4 | 487 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
488 | gnutls_x509_crt_t crt; |
489 | ||
490 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
491 | } | |
059ec3d9 PH |
492 | } |
493 | ||
494 | ||
495 | ||
17c76198 | 496 | |
059ec3d9 | 497 | /************************************************* |
575643cd | 498 | * Setup up DH parameters * |
059ec3d9 PH |
499 | *************************************************/ |
500 | ||
575643cd | 501 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
502 | be re-generated every so often, depending on security policy. What we do is to |
503 | keep these parameters in a file in the spool directory. If the file does not | |
504 | exist, we generate them. This means that it is easy to cause a regeneration. | |
505 | ||
506 | The new file is written as a temporary file and renamed, so that an incomplete | |
507 | file is never present. If two processes both compute some new parameters, you | |
508 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
509 | prevent this. | |
510 | ||
059ec3d9 PH |
511 | Returns: OK/DEFER/FAIL |
512 | */ | |
513 | ||
514 | static int | |
cf0c6164 | 515 | init_server_dh(uschar ** errstr) |
059ec3d9 | 516 | { |
17c76198 PP |
517 | int fd, rc; |
518 | unsigned int dh_bits; | |
27f19eb4 | 519 | gnutls_datum_t m; |
a799883d PP |
520 | uschar filename_buf[PATH_MAX]; |
521 | uschar *filename = NULL; | |
17c76198 | 522 | size_t sz; |
a799883d PP |
523 | uschar *exp_tls_dhparam; |
524 | BOOL use_file_in_spool = FALSE; | |
525 | BOOL use_fixed_file = FALSE; | |
17c76198 | 526 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 527 | |
17c76198 | 528 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 529 | |
17c76198 | 530 | rc = gnutls_dh_params_init(&dh_server_params); |
47195144 | 531 | exim_gnutls_err_check(rc, US"gnutls_dh_params_init"); |
059ec3d9 | 532 | |
a799883d PP |
533 | m.data = NULL; |
534 | m.size = 0; | |
535 | ||
cf0c6164 | 536 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
537 | return DEFER; |
538 | ||
539 | if (!exp_tls_dhparam) | |
540 | { | |
541 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
542 | m.data = US std_dh_prime_default(); | |
543 | m.size = Ustrlen(m.data); | |
544 | } | |
545 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
546 | use_file_in_spool = TRUE; | |
547 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
548 | { | |
549 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
550 | return OK; | |
551 | } | |
552 | else if (exp_tls_dhparam[0] != '/') | |
553 | { | |
f5d25c2b | 554 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
cf0c6164 | 555 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); |
a799883d PP |
556 | m.size = Ustrlen(m.data); |
557 | } | |
558 | else | |
559 | { | |
560 | use_fixed_file = TRUE; | |
561 | filename = exp_tls_dhparam; | |
562 | } | |
563 | ||
564 | if (m.data) | |
565 | { | |
566 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
47195144 | 567 | exim_gnutls_err_check(rc, US"gnutls_dh_params_import_pkcs3"); |
a799883d PP |
568 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); |
569 | return OK; | |
570 | } | |
571 | ||
af3498d6 PP |
572 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
573 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
574 | different filename and ensure we have sufficient bits. */ |
575 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
576 | if (!dh_bits) | |
cf0c6164 | 577 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 578 | DEBUG(D_tls) |
b34fc30c | 579 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
580 | dh_bits); |
581 | #else | |
582 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
583 | DEBUG(D_tls) | |
584 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
585 | dh_bits); | |
586 | #endif | |
059ec3d9 | 587 | |
3375e053 PP |
588 | /* Some clients have hard-coded limits. */ |
589 | if (dh_bits > tls_dh_max_bits) | |
590 | { | |
591 | DEBUG(D_tls) | |
592 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
593 | tls_dh_max_bits); | |
594 | dh_bits = tls_dh_max_bits; | |
595 | } | |
596 | ||
a799883d PP |
597 | if (use_file_in_spool) |
598 | { | |
599 | if (!string_format(filename_buf, sizeof(filename_buf), | |
600 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 601 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
602 | filename = filename_buf; |
603 | } | |
059ec3d9 | 604 | |
b5aea5e1 | 605 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 606 | parameters. */ |
059ec3d9 | 607 | |
f5d25c2b | 608 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 609 | { |
b5aea5e1 | 610 | struct stat statbuf; |
17c76198 PP |
611 | FILE *fp; |
612 | int saved_errno; | |
613 | ||
614 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
615 | { | |
616 | saved_errno = errno; | |
617 | (void)close(fd); | |
cf0c6164 | 618 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
619 | } |
620 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
621 | { |
622 | (void)close(fd); | |
cf0c6164 | 623 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 624 | } |
40c90bca | 625 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
626 | { |
627 | saved_errno = errno; | |
628 | (void)close(fd); | |
629 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
cf0c6164 | 630 | strerror(saved_errno), NULL, errstr); |
b5aea5e1 | 631 | } |
059ec3d9 | 632 | |
b5aea5e1 | 633 | m.size = statbuf.st_size; |
40c90bca | 634 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
635 | { |
636 | fclose(fp); | |
cf0c6164 | 637 | return tls_error(US"malloc failed", strerror(errno), NULL, errstr); |
17c76198 | 638 | } |
40c90bca | 639 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
640 | { |
641 | saved_errno = errno; | |
642 | fclose(fp); | |
643 | free(m.data); | |
cf0c6164 | 644 | return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
645 | } |
646 | fclose(fp); | |
b5aea5e1 | 647 | |
17c76198 | 648 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 649 | free(m.data); |
47195144 | 650 | exim_gnutls_err_check(rc, US"gnutls_dh_params_import_pkcs3"); |
17c76198 | 651 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); |
b5aea5e1 PH |
652 | } |
653 | ||
654 | /* If the file does not exist, fall through to compute new data and cache it. | |
655 | If there was any other opening error, it is serious. */ | |
656 | ||
182ad5cf PH |
657 | else if (errno == ENOENT) |
658 | { | |
17c76198 | 659 | rc = -1; |
182ad5cf | 660 | DEBUG(D_tls) |
17c76198 | 661 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
662 | } |
663 | else | |
17c76198 | 664 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 665 | NULL, NULL, errstr); |
b5aea5e1 PH |
666 | |
667 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
668 | is not useful. One particular case of this is when upgrading from an older | |
669 | release of Exim in which the data was stored in a different format. We don't | |
670 | try to be clever and support both formats; we just regenerate new data in this | |
671 | case. */ | |
672 | ||
17c76198 | 673 | if (rc < 0) |
b5aea5e1 | 674 | { |
17c76198 | 675 | uschar *temp_fn; |
201f5254 | 676 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 677 | |
17c76198 PP |
678 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
679 | return tls_error(US"Filename too long to generate replacement", | |
cf0c6164 | 680 | CS filename, NULL, errstr); |
059ec3d9 | 681 | |
17c76198 | 682 | temp_fn = string_copy(US "%s.XXXXXXX"); |
f5d25c2b | 683 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
cf0c6164 | 684 | return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); |
059ec3d9 PH |
685 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
686 | ||
201f5254 PP |
687 | /* GnuTLS overshoots! |
688 | * If we ask for 2236, we might get 2237 or more. | |
689 | * But there's no way to ask GnuTLS how many bits there really are. | |
690 | * We can ask how many bits were used in a TLS session, but that's it! | |
691 | * The prime itself is hidden behind too much abstraction. | |
692 | * So we ask for less, and proceed on a wing and a prayer. | |
693 | * First attempt, subtracted 3 for 2233 and got 2240. | |
694 | */ | |
cae6e576 | 695 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
696 | { |
697 | dh_bits_gen = dh_bits - 10; | |
698 | DEBUG(D_tls) | |
699 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
700 | dh_bits_gen); | |
701 | } | |
702 | ||
703 | DEBUG(D_tls) | |
704 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
705 | dh_bits_gen); | |
706 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
47195144 | 707 | exim_gnutls_err_check(rc, US"gnutls_dh_params_generate2"); |
17c76198 PP |
708 | |
709 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
710 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
711 | sample apps handle this. */ | |
712 | ||
713 | sz = 0; | |
714 | m.data = NULL; | |
715 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
716 | m.data, &sz); | |
717 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
47195144 | 718 | exim_gnutls_err_check(rc, US"gnutls_dh_params_export_pkcs3(NULL) sizing"); |
17c76198 | 719 | m.size = sz; |
40c90bca | 720 | if (!(m.data = malloc(m.size))) |
cf0c6164 | 721 | return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); |
40c90bca | 722 | |
1f00591e | 723 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 724 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 725 | m.data, &sz); |
17c76198 PP |
726 | if (rc != GNUTLS_E_SUCCESS) |
727 | { | |
728 | free(m.data); | |
47195144 | 729 | exim_gnutls_err_check(rc, US"gnutls_dh_params_export_pkcs3() real"); |
17c76198 | 730 | } |
1f00591e | 731 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 732 | |
f5d25c2b | 733 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 PP |
734 | { |
735 | free(m.data); | |
736 | return tls_error(US"TLS cache write D-H params failed", | |
cf0c6164 | 737 | strerror(errno), NULL, errstr); |
17c76198 | 738 | } |
b5aea5e1 | 739 | free(m.data); |
f5d25c2b | 740 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
17c76198 | 741 | return tls_error(US"TLS cache write D-H params final newline failed", |
cf0c6164 | 742 | strerror(errno), NULL, errstr); |
17c76198 | 743 | |
f5d25c2b | 744 | if ((rc = close(fd))) |
cf0c6164 | 745 | return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); |
059ec3d9 | 746 | |
17c76198 PP |
747 | if (Urename(temp_fn, filename) < 0) |
748 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
cf0c6164 | 749 | temp_fn, filename), strerror(errno), NULL, errstr); |
059ec3d9 | 750 | |
17c76198 | 751 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
752 | } |
753 | ||
17c76198 | 754 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
755 | return OK; |
756 | } | |
757 | ||
758 | ||
759 | ||
760 | ||
23bb6982 JH |
761 | /* Create and install a selfsigned certificate, for use in server mode */ |
762 | ||
763 | static int | |
cf0c6164 | 764 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
765 | { |
766 | gnutls_x509_crt_t cert = NULL; | |
767 | time_t now; | |
768 | gnutls_x509_privkey_t pkey = NULL; | |
769 | const uschar * where; | |
770 | int rc; | |
771 | ||
772 | where = US"initialising pkey"; | |
773 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
774 | ||
775 | where = US"initialising cert"; | |
776 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
777 | ||
778 | where = US"generating pkey"; | |
779 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 780 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
23bb6982 | 781 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), |
76075bb5 JH |
782 | #else |
783 | 1024, | |
784 | #endif | |
785 | 0))) | |
23bb6982 JH |
786 | goto err; |
787 | ||
788 | where = US"configuring cert"; | |
789 | now = 0; | |
790 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) | |
791 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
792 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
793 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
794 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
795 | ||
796 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
797 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
798 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
799 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
800 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
801 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
802 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
803 | ) | |
804 | goto err; | |
805 | ||
806 | where = US"signing cert"; | |
807 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
808 | ||
809 | where = US"installing selfsign cert"; | |
810 | /* Since: 2.4.0 */ | |
811 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
812 | goto err; | |
813 | ||
814 | rc = OK; | |
815 | ||
816 | out: | |
817 | if (cert) gnutls_x509_crt_deinit(cert); | |
818 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
819 | return rc; | |
820 | ||
821 | err: | |
cf0c6164 | 822 | rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); |
23bb6982 JH |
823 | goto out; |
824 | } | |
825 | ||
826 | ||
827 | ||
828 | ||
47195144 JH |
829 | /* Add certificate and key, from files. |
830 | ||
831 | Return: | |
832 | Zero or negative: good. Negate value for certificate index if < 0. | |
833 | Greater than zero: FAIL or DEFER code. | |
834 | */ | |
835 | ||
ba86e143 JH |
836 | static int |
837 | tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, | |
838 | uschar * certfile, uschar * keyfile, uschar ** errstr) | |
839 | { | |
840 | int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, | |
841 | CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); | |
47195144 JH |
842 | if (rc < 0) |
843 | return tls_error( | |
844 | string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile), | |
845 | gnutls_strerror(rc), host, errstr); | |
846 | return -rc; | |
ba86e143 JH |
847 | } |
848 | ||
849 | ||
059ec3d9 | 850 | /************************************************* |
17c76198 | 851 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
852 | *************************************************/ |
853 | ||
17c76198 PP |
854 | /* Called from both server and client code, via tls_init(), and also from |
855 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
856 | ||
857 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
858 | ||
859 | The callback should not call us unless state->trigger_sni_changes is true, | |
860 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
861 | |
862 | Arguments: | |
17c76198 | 863 | state exim_gnutls_state_st * |
cf0c6164 | 864 | errstr error string pointer |
059ec3d9 PH |
865 | |
866 | Returns: OK/DEFER/FAIL | |
867 | */ | |
868 | ||
869 | static int | |
ba86e143 | 870 | tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 871 | { |
1365611d | 872 | struct stat statbuf; |
059ec3d9 | 873 | int rc; |
17c76198 PP |
874 | const host_item *host = state->host; /* macro should be reconsidered? */ |
875 | uschar *saved_tls_certificate = NULL; | |
876 | uschar *saved_tls_privatekey = NULL; | |
877 | uschar *saved_tls_verify_certificates = NULL; | |
878 | uschar *saved_tls_crl = NULL; | |
879 | int cert_count; | |
880 | ||
881 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 882 | if (!host) /* server */ |
17c76198 PP |
883 | if (!state->received_sni) |
884 | { | |
ba86e143 JH |
885 | if ( state->tls_certificate |
886 | && ( Ustrstr(state->tls_certificate, US"tls_sni") | |
887 | || Ustrstr(state->tls_certificate, US"tls_in_sni") | |
888 | || Ustrstr(state->tls_certificate, US"tls_out_sni") | |
889 | ) ) | |
17c76198 PP |
890 | { |
891 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
892 | state->trigger_sni_changes = TRUE; | |
893 | } | |
894 | } | |
895 | else | |
896 | { | |
1365611d | 897 | /* useful for debugging */ |
17c76198 PP |
898 | saved_tls_certificate = state->exp_tls_certificate; |
899 | saved_tls_privatekey = state->exp_tls_privatekey; | |
900 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
901 | saved_tls_crl = state->exp_tls_crl; | |
902 | } | |
059ec3d9 | 903 | |
1365611d | 904 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
47195144 JH |
905 | exim_gnutls_err_check(rc, US"gnutls_certificate_allocate_credentials"); |
906 | ||
907 | #ifdef SUPPORT_SRV_OCSP_STACK | |
908 | gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2); | |
909 | #endif | |
1365611d | 910 | |
17c76198 PP |
911 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
912 | state members, assuming consistent naming; and expand_check() returns | |
913 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 914 | |
17c76198 PP |
915 | /* check if we at least have a certificate, before doing expensive |
916 | D-H generation. */ | |
059ec3d9 | 917 | |
cf0c6164 | 918 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 919 | return DEFER; |
059ec3d9 | 920 | |
17c76198 | 921 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 922 | |
23bb6982 JH |
923 | if ( !state->exp_tls_certificate |
924 | || !*state->exp_tls_certificate | |
925 | ) | |
2b4a568d | 926 | if (!host) |
cf0c6164 | 927 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
928 | else |
929 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 930 | |
cf0c6164 | 931 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
932 | return DEFER; |
933 | ||
17c76198 PP |
934 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
935 | ||
936 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 937 | { |
17c76198 PP |
938 | state->tls_privatekey = state->tls_certificate; |
939 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 940 | } |
c91535f3 | 941 | |
059ec3d9 | 942 | |
17c76198 | 943 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
944 | { |
945 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
946 | state->exp_tls_certificate, state->exp_tls_privatekey); |
947 | ||
948 | if (state->received_sni) | |
23bb6982 JH |
949 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
950 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
951 | ) | |
17c76198 | 952 | { |
b34fc30c | 953 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
954 | } |
955 | else | |
956 | { | |
b34fc30c | 957 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 958 | } |
059ec3d9 | 959 | |
ba86e143 JH |
960 | if (!host) /* server */ |
961 | { | |
962 | const uschar * clist = state->exp_tls_certificate; | |
963 | const uschar * klist = state->exp_tls_privatekey; | |
47195144 JH |
964 | const uschar * olist; |
965 | int csep = 0, ksep = 0, osep = 0, cnt = 0; | |
966 | uschar * cfile, * kfile, * ofile; | |
967 | ||
968 | #ifndef DISABLE_OCSP | |
969 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr)) | |
970 | return DEFER; | |
971 | olist = ofile; | |
972 | #endif | |
ba86e143 JH |
973 | |
974 | while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) | |
47195144 | 975 | |
ba86e143 JH |
976 | if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) |
977 | return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); | |
47195144 | 978 | else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr))) |
ba86e143 JH |
979 | return rc; |
980 | else | |
47195144 JH |
981 | { |
982 | int gnutls_cert_index = -rc; | |
ba86e143 | 983 | DEBUG(D_tls) debug_printf("TLS: cert/key %s registered\n", cfile); |
47195144 JH |
984 | |
985 | /* Set the OCSP stapling server info */ | |
986 | ||
987 | #ifndef DISABLE_OCSP | |
988 | if (tls_ocsp_file) | |
989 | if (gnutls_buggy_ocsp) | |
990 | { | |
991 | DEBUG(D_tls) | |
992 | debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
993 | } | |
994 | else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) | |
995 | { | |
996 | /* Use the full callback method for stapling just to get | |
997 | observability. More efficient would be to read the file once only, | |
998 | if it never changed (due to SNI). Would need restart on file update, | |
999 | or watch datestamp. */ | |
1000 | ||
1001 | # ifdef SUPPORT_SRV_OCSP_STACK | |
1002 | rc = gnutls_certificate_set_ocsp_status_request_function2( | |
1003 | state->x509_cred, gnutls_cert_index, | |
1004 | server_ocsp_stapling_cb, ofile); | |
1005 | ||
1006 | exim_gnutls_err_check(rc, | |
1007 | US"gnutls_certificate_set_ocsp_status_request_function2"); | |
1008 | # else | |
1009 | if (cnt++ > 0) | |
1010 | { | |
1011 | DEBUG(D_tls) | |
1012 | debug_printf("oops; multiple OCSP files not supported\n"); | |
1013 | break; | |
1014 | } | |
1015 | gnutls_certificate_set_ocsp_status_request_function( | |
1016 | state->x509_cred, server_ocsp_stapling_cb, ofile); | |
1017 | # endif | |
1018 | ||
1019 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); | |
1020 | } | |
1021 | else | |
1022 | DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); | |
1023 | #endif | |
1024 | } | |
ba86e143 JH |
1025 | } |
1026 | else | |
1027 | { | |
47195144 | 1028 | if (0 < (rc = tls_add_certfile(state, host, |
ba86e143 JH |
1029 | state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) |
1030 | return rc; | |
1031 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
1032 | } | |
1033 | ||
b34fc30c | 1034 | } /* tls_certificate */ |
059ec3d9 | 1035 | |
2b4a568d | 1036 | |
059ec3d9 PH |
1037 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
1038 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
1039 | error message is provided. However, if we just refrain from setting anything up | |
1040 | in that case, certificate verification fails, which seems to be the correct | |
1041 | behaviour. */ | |
1042 | ||
610ff438 | 1043 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 1044 | { |
cf0c6164 | 1045 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 1046 | return DEFER; |
610ff438 JH |
1047 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
1048 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1049 | state->exp_tls_verify_certificates = NULL; | |
1050 | #endif | |
17c76198 | 1051 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 1052 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 1053 | return DEFER; |
059ec3d9 | 1054 | |
1365611d PP |
1055 | if (!(state->exp_tls_verify_certificates && |
1056 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
1057 | { |
1058 | DEBUG(D_tls) | |
1365611d PP |
1059 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
1060 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 1061 | return OK; |
b34fc30c | 1062 | } |
1365611d | 1063 | } |
83e2f8a2 PP |
1064 | else |
1065 | { | |
1066 | DEBUG(D_tls) | |
1067 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
1068 | return OK; | |
1069 | } | |
17c76198 | 1070 | |
cb1d7830 JH |
1071 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
1072 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1073 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
1074 | else | |
1075 | #endif | |
1365611d | 1076 | { |
cb1d7830 JH |
1077 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
1078 | { | |
1079 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
1080 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
1081 | strerror(errno)); | |
1082 | return DEFER; | |
1083 | } | |
17c76198 | 1084 | |
a7fec7a7 | 1085 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1086 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1087 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1088 | other weirdness. The thing we really want to check is that it's not a | |
1089 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1090 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1091 | if (S_ISDIR(statbuf.st_mode)) |
1092 | { | |
1093 | DEBUG(D_tls) | |
1094 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1095 | state->exp_tls_verify_certificates); | |
1096 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1097 | "tls_verify_certificates \"%s\" is a directory", | |
1098 | state->exp_tls_verify_certificates); | |
1099 | return DEFER; | |
1100 | } | |
a7fec7a7 | 1101 | #endif |
059ec3d9 | 1102 | |
cb1d7830 JH |
1103 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1104 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1105 | |
cb1d7830 JH |
1106 | if (statbuf.st_size == 0) |
1107 | { | |
1108 | DEBUG(D_tls) | |
1109 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1110 | return OK; | |
1111 | } | |
059ec3d9 | 1112 | |
cb1d7830 | 1113 | cert_count = |
a7fec7a7 JH |
1114 | |
1115 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1116 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1117 | ? | |
1118 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1119 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1120 | : | |
a7fec7a7 | 1121 | #endif |
cb1d7830 JH |
1122 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1123 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1124 | } | |
a7fec7a7 | 1125 | |
1365611d PP |
1126 | if (cert_count < 0) |
1127 | { | |
1128 | rc = cert_count; | |
47195144 | 1129 | exim_gnutls_err_check(rc, US"setting certificate trust"); |
1365611d PP |
1130 | } |
1131 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1132 | |
5c8cda3a PP |
1133 | if (state->tls_crl && *state->tls_crl && |
1134 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1135 | { |
5c8cda3a PP |
1136 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1137 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1138 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1139 | if (cert_count < 0) | |
1365611d | 1140 | { |
5c8cda3a | 1141 | rc = cert_count; |
47195144 | 1142 | exim_gnutls_err_check(rc, US"gnutls_certificate_set_x509_crl_file"); |
1365611d | 1143 | } |
5c8cda3a | 1144 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1145 | } |
059ec3d9 | 1146 | |
059ec3d9 PH |
1147 | return OK; |
1148 | } | |
1149 | ||
1150 | ||
1151 | ||
1152 | ||
1365611d PP |
1153 | /************************************************* |
1154 | * Set X.509 state variables * | |
1155 | *************************************************/ | |
1156 | ||
1157 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1158 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1159 | structure. Which means various other non-re-expanded pieces of state | |
1160 | need to be re-set in the new struct, so the setting logic is pulled | |
1161 | out to this. | |
1162 | ||
1163 | Arguments: | |
1164 | state exim_gnutls_state_st * | |
cf0c6164 | 1165 | errstr error string pointer |
1365611d PP |
1166 | |
1167 | Returns: OK/DEFER/FAIL | |
1168 | */ | |
1169 | ||
1170 | static int | |
cf0c6164 | 1171 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1172 | { |
1173 | int rc; | |
1174 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1175 | ||
1176 | /* Create D-H parameters, or read them from the cache file. This function does | |
1177 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1178 | client-side params. */ | |
1179 | ||
1180 | if (!state->host) | |
1181 | { | |
1182 | if (!dh_server_params) | |
1183 | { | |
cf0c6164 | 1184 | rc = init_server_dh(errstr); |
1365611d PP |
1185 | if (rc != OK) return rc; |
1186 | } | |
1187 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1188 | } | |
1189 | ||
1190 | /* Link the credentials to the session. */ | |
1191 | ||
1192 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
47195144 | 1193 | exim_gnutls_err_check(rc, US"gnutls_credentials_set"); |
1365611d PP |
1194 | |
1195 | return OK; | |
1196 | } | |
1197 | ||
059ec3d9 | 1198 | /************************************************* |
17c76198 | 1199 | * Initialize for GnuTLS * |
059ec3d9 PH |
1200 | *************************************************/ |
1201 | ||
9196d5bf | 1202 | |
4fb7df6d JH |
1203 | #ifndef DISABLE_OCSP |
1204 | ||
9196d5bf JH |
1205 | static BOOL |
1206 | tls_is_buggy_ocsp(void) | |
1207 | { | |
1208 | const uschar * s; | |
1209 | uschar maj, mid, mic; | |
1210 | ||
1211 | s = CUS gnutls_check_version(NULL); | |
1212 | maj = atoi(CCS s); | |
1213 | if (maj == 3) | |
1214 | { | |
1215 | while (*s && *s != '.') s++; | |
1216 | mid = atoi(CCS ++s); | |
1217 | if (mid <= 2) | |
1218 | return TRUE; | |
1219 | else if (mid >= 5) | |
1220 | return FALSE; | |
1221 | else | |
1222 | { | |
1223 | while (*s && *s != '.') s++; | |
1224 | mic = atoi(CCS ++s); | |
1225 | return mic <= (mid == 3 ? 16 : 3); | |
1226 | } | |
1227 | } | |
1228 | return FALSE; | |
1229 | } | |
1230 | ||
4fb7df6d | 1231 | #endif |
9196d5bf JH |
1232 | |
1233 | ||
17c76198 PP |
1234 | /* Called from both server and client code. In the case of a server, errors |
1235 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1236 | |
1237 | Arguments: | |
17c76198 PP |
1238 | host connected host, if client; NULL if server |
1239 | certificate certificate file | |
1240 | privatekey private key file | |
1241 | sni TLS SNI to send, sometimes when client; else NULL | |
1242 | cas CA certs file | |
1243 | crl CRL file | |
1244 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1245 | caller_state returned state-info structure |
cf0c6164 | 1246 | errstr error string pointer |
059ec3d9 | 1247 | |
17c76198 | 1248 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1249 | */ |
1250 | ||
17c76198 PP |
1251 | static int |
1252 | tls_init( | |
1253 | const host_item *host, | |
1254 | const uschar *certificate, | |
1255 | const uschar *privatekey, | |
1256 | const uschar *sni, | |
1257 | const uschar *cas, | |
1258 | const uschar *crl, | |
1259 | const uschar *require_ciphers, | |
cf0c6164 JH |
1260 | exim_gnutls_state_st **caller_state, |
1261 | uschar ** errstr) | |
059ec3d9 | 1262 | { |
17c76198 PP |
1263 | exim_gnutls_state_st *state; |
1264 | int rc; | |
1265 | size_t sz; | |
1266 | const char *errpos; | |
1267 | uschar *p; | |
1268 | BOOL want_default_priorities; | |
1269 | ||
1270 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1271 | { |
17c76198 PP |
1272 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1273 | ||
a5f239e4 PP |
1274 | #ifdef HAVE_GNUTLS_PKCS11 |
1275 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1276 | which loads modules from a config file, which sounds good and may be wanted | |
1277 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1278 | environment variables are used and so breaks for users calling mailq. | |
1279 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1280 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1281 | { |
1282 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
47195144 | 1283 | exim_gnutls_err_check(rc, US"gnutls_pkcs11_init"); |
a5f239e4 PP |
1284 | } |
1285 | #endif | |
1286 | ||
17c76198 | 1287 | rc = gnutls_global_init(); |
47195144 | 1288 | exim_gnutls_err_check(rc, US"gnutls_global_init"); |
17c76198 PP |
1289 | |
1290 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1291 | DEBUG(D_tls) | |
059ec3d9 | 1292 | { |
17c76198 PP |
1293 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1294 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1295 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1296 | } |
17c76198 PP |
1297 | #endif |
1298 | ||
4fb7df6d JH |
1299 | #ifndef DISABLE_OCSP |
1300 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1301 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1302 | #endif |
9196d5bf | 1303 | |
17c76198 | 1304 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1305 | } |
059ec3d9 | 1306 | |
17c76198 PP |
1307 | if (host) |
1308 | { | |
1309 | state = &state_client; | |
1310 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1311 | state->tlsp = &tls_out; |
17c76198 PP |
1312 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1313 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1314 | } | |
1315 | else | |
1316 | { | |
1317 | state = &state_server; | |
1318 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1319 | state->tlsp = &tls_in; |
17c76198 PP |
1320 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1321 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1322 | } | |
47195144 | 1323 | exim_gnutls_err_check(rc, US"gnutls_init"); |
059ec3d9 | 1324 | |
17c76198 | 1325 | state->host = host; |
059ec3d9 | 1326 | |
17c76198 PP |
1327 | state->tls_certificate = certificate; |
1328 | state->tls_privatekey = privatekey; | |
5779e6aa | 1329 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1330 | state->tls_sni = sni; |
1331 | state->tls_verify_certificates = cas; | |
1332 | state->tls_crl = crl; | |
059ec3d9 | 1333 | |
17c76198 PP |
1334 | /* This handles the variables that might get re-expanded after TLS SNI; |
1335 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1336 | |
17c76198 PP |
1337 | DEBUG(D_tls) |
1338 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1339 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1340 | |
1365611d PP |
1341 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1342 | requires a new structure afterwards. */ | |
83da1223 | 1343 | |
cf0c6164 | 1344 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1345 | |
17c76198 PP |
1346 | /* set SNI in client, only */ |
1347 | if (host) | |
1348 | { | |
cf0c6164 | 1349 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1350 | return DEFER; |
0df4ab80 | 1351 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1352 | { |
1353 | DEBUG(D_tls) | |
0df4ab80 JH |
1354 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1355 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1356 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1357 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
47195144 | 1358 | exim_gnutls_err_check(rc, US"gnutls_server_name_set"); |
17c76198 PP |
1359 | } |
1360 | } | |
1361 | else if (state->tls_sni) | |
1362 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
ba86e143 | 1363 | "have an SNI set for a server [%s]\n", state->tls_sni); |
83da1223 | 1364 | |
17c76198 | 1365 | /* This is the priority string support, |
42bfef1e | 1366 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1367 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1368 | This was backwards incompatible, but means Exim no longer needs to track | |
1369 | all algorithms and provide string forms for them. */ | |
83da1223 | 1370 | |
17c76198 | 1371 | want_default_priorities = TRUE; |
83da1223 | 1372 | |
17c76198 | 1373 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1374 | { |
cf0c6164 | 1375 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1376 | return DEFER; |
1377 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1378 | { |
17c76198 PP |
1379 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1380 | state->exp_tls_require_ciphers); | |
1381 | ||
1382 | rc = gnutls_priority_init(&state->priority_cache, | |
1383 | CS state->exp_tls_require_ciphers, &errpos); | |
1384 | want_default_priorities = FALSE; | |
1385 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1386 | } |
1387 | } | |
17c76198 PP |
1388 | if (want_default_priorities) |
1389 | { | |
83e2f8a2 PP |
1390 | DEBUG(D_tls) |
1391 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1392 | exim_default_gnutls_priority); | |
17c76198 PP |
1393 | rc = gnutls_priority_init(&state->priority_cache, |
1394 | exim_default_gnutls_priority, &errpos); | |
1395 | p = US exim_default_gnutls_priority; | |
1396 | } | |
83da1223 | 1397 | |
47195144 | 1398 | exim_gnutls_err_check(rc, string_sprintf( |
17c76198 PP |
1399 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", |
1400 | p, errpos - CS p, errpos)); | |
1401 | ||
1402 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
47195144 | 1403 | exim_gnutls_err_check(rc, US"gnutls_priority_set"); |
17c76198 PP |
1404 | |
1405 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1406 | ||
1407 | /* Reduce security in favour of increased compatibility, if the admin | |
1408 | decides to make that trade-off. */ | |
1409 | if (gnutls_compat_mode) | |
83da1223 | 1410 | { |
17c76198 PP |
1411 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1412 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1413 | gnutls_session_enable_compatibility_mode(state->session); | |
1414 | #else | |
1415 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1416 | #endif | |
83da1223 PH |
1417 | } |
1418 | ||
17c76198 | 1419 | *caller_state = state; |
17c76198 | 1420 | return OK; |
83da1223 PH |
1421 | } |
1422 | ||
1423 | ||
1424 | ||
059ec3d9 | 1425 | /************************************************* |
17c76198 | 1426 | * Extract peer information * |
059ec3d9 PH |
1427 | *************************************************/ |
1428 | ||
17c76198 | 1429 | /* Called from both server and client code. |
4fe99a6c PP |
1430 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1431 | and we use that to detect double-calls. | |
059ec3d9 | 1432 | |
75fe387d PP |
1433 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1434 | for logging in the server side, but for the client side, we log after teardown | |
1435 | in src/deliver.c. While the session is up, we can twist about states and | |
1436 | repoint tls_* globals, but those variables used for logging or other variable | |
1437 | expansion that happens _after_ delivery need to have a longer life-time. | |
1438 | ||
1439 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1440 | doing this more than once per generation of a state context. We set them in | |
1441 | the state context, and repoint tls_* to them. After the state goes away, the | |
1442 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1443 | ||
1444 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1445 | don't apply. | |
1446 | ||
059ec3d9 | 1447 | Arguments: |
17c76198 | 1448 | state exim_gnutls_state_st * |
cf0c6164 | 1449 | errstr pointer to error string |
059ec3d9 | 1450 | |
17c76198 | 1451 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1452 | */ |
1453 | ||
17c76198 | 1454 | static int |
cf0c6164 | 1455 | peer_status(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 1456 | { |
75fe387d | 1457 | uschar cipherbuf[256]; |
27f19eb4 | 1458 | const gnutls_datum_t *cert_list; |
75fe387d | 1459 | int old_pool, rc; |
17c76198 | 1460 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1461 | gnutls_protocol_t protocol; |
1462 | gnutls_cipher_algorithm_t cipher; | |
1463 | gnutls_kx_algorithm_t kx; | |
1464 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1465 | gnutls_certificate_type_t ct; |
1466 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1467 | uschar *p, *dn_buf; |
17c76198 | 1468 | size_t sz; |
059ec3d9 | 1469 | |
4fe99a6c | 1470 | if (state->have_set_peerdn) |
17c76198 | 1471 | return OK; |
4fe99a6c | 1472 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1473 | |
4fe99a6c | 1474 | state->peerdn = NULL; |
059ec3d9 | 1475 | |
4fe99a6c PP |
1476 | /* tls_cipher */ |
1477 | cipher = gnutls_cipher_get(state->session); | |
1478 | protocol = gnutls_protocol_get_version(state->session); | |
1479 | mac = gnutls_mac_get(state->session); | |
1480 | kx = gnutls_kx_get(state->session); | |
1481 | ||
75fe387d | 1482 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1483 | "%s:%s:%d", |
1484 | gnutls_protocol_get_name(protocol), | |
1485 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1486 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1487 | ||
1488 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1489 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1490 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1491 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1492 | if (isspace(*p)) |
1493 | *p = '-'; | |
75fe387d PP |
1494 | old_pool = store_pool; |
1495 | store_pool = POOL_PERM; | |
1496 | state->ciphersuite = string_copy(cipherbuf); | |
1497 | store_pool = old_pool; | |
817d9f57 | 1498 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1499 | |
1500 | /* tls_peerdn */ | |
17c76198 | 1501 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1502 | |
17c76198 PP |
1503 | if (cert_list == NULL || cert_list_size == 0) |
1504 | { | |
17c76198 PP |
1505 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1506 | cert_list, cert_list_size); | |
e51c7be2 | 1507 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1508 | return tls_error(US"certificate verification failed", |
cf0c6164 | 1509 | "no certificate received from peer", state->host, errstr); |
17c76198 PP |
1510 | return OK; |
1511 | } | |
059ec3d9 | 1512 | |
17c76198 PP |
1513 | ct = gnutls_certificate_type_get(state->session); |
1514 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1515 | { |
17c76198 | 1516 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1517 | DEBUG(D_tls) |
1518 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1519 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1520 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1521 | ctn, state->host, errstr); |
17c76198 | 1522 | return OK; |
83da1223 | 1523 | } |
059ec3d9 | 1524 | |
e51c7be2 JH |
1525 | #define exim_gnutls_peer_err(Label) \ |
1526 | do { \ | |
1527 | if (rc != GNUTLS_E_SUCCESS) \ | |
1528 | { \ | |
1529 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1530 | (Label), gnutls_strerror(rc)); \ | |
1531 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
cf0c6164 | 1532 | return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ |
e51c7be2 JH |
1533 | return OK; \ |
1534 | } \ | |
1535 | } while (0) | |
17c76198 | 1536 | |
9d1c15ef JH |
1537 | rc = import_cert(&cert_list[0], &crt); |
1538 | exim_gnutls_peer_err(US"cert 0"); | |
1539 | ||
1540 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1541 | |
17c76198 PP |
1542 | sz = 0; |
1543 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1544 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1545 | { |
17c76198 PP |
1546 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1547 | return FAIL; /* should not happen */ | |
059ec3d9 | 1548 | } |
17c76198 PP |
1549 | dn_buf = store_get_perm(sz); |
1550 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1551 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1552 | |
17c76198 PP |
1553 | state->peerdn = dn_buf; |
1554 | ||
1555 | return OK; | |
1556 | #undef exim_gnutls_peer_err | |
1557 | } | |
059ec3d9 | 1558 | |
059ec3d9 | 1559 | |
059ec3d9 | 1560 | |
059ec3d9 | 1561 | |
17c76198 PP |
1562 | /************************************************* |
1563 | * Verify peer certificate * | |
1564 | *************************************************/ | |
059ec3d9 | 1565 | |
17c76198 PP |
1566 | /* Called from both server and client code. |
1567 | *Should* be using a callback registered with | |
1568 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1569 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1570 | |
17c76198 | 1571 | Arguments: |
899b8bbc JH |
1572 | state exim_gnutls_state_st * |
1573 | errstr where to put an error message | |
059ec3d9 | 1574 | |
17c76198 PP |
1575 | Returns: |
1576 | FALSE if the session should be rejected | |
1577 | TRUE if the cert is okay or we just don't care | |
1578 | */ | |
059ec3d9 | 1579 | |
17c76198 | 1580 | static BOOL |
28646fa9 | 1581 | verify_certificate(exim_gnutls_state_st * state, uschar ** errstr) |
17c76198 PP |
1582 | { |
1583 | int rc; | |
899b8bbc JH |
1584 | uint verify; |
1585 | ||
1586 | if (state->verify_requirement == VERIFY_NONE) | |
1587 | return TRUE; | |
17c76198 | 1588 | |
cf0c6164 | 1589 | *errstr = NULL; |
17c76198 | 1590 | |
cf0c6164 | 1591 | if ((rc = peer_status(state, errstr)) != OK) |
e6060e2c | 1592 | { |
17c76198 | 1593 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1594 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1595 | } |
1596 | else | |
899b8bbc JH |
1597 | |
1598 | { | |
1599 | #ifdef SUPPORT_DANE | |
1600 | if (state->verify_requirement == VERIFY_DANE && state->host) | |
1601 | { | |
1602 | /* Using dane_verify_session_crt() would be easy, as it does it all for us | |
1603 | including talking to a DNS resolver. But we want to do that bit ourselves | |
1604 | as the testsuite intercepts and fakes its own DNS environment. */ | |
1605 | ||
1606 | dane_state_t s; | |
1607 | dane_query_t r; | |
899b8bbc | 1608 | uint lsize; |
94c13285 JH |
1609 | const gnutls_datum_t * certlist = |
1610 | gnutls_certificate_get_peers(state->session, &lsize); | |
1611 | int usage = tls_out.tlsa_usage; | |
1612 | ||
1613 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION | |
1614 | /* Split the TLSA records into two sets, TA and EE selectors. Run the | |
1615 | dane-verification separately so that we know which selector verified; | |
1616 | then we know whether to do CA-chain-verification and name-verification | |
1617 | (needed for TA but not EE). */ | |
1618 | ||
1619 | if (usage == ((1<<DANESSL_USAGE_DANE_TA) | (1<<DANESSL_USAGE_DANE_EE))) | |
1620 | { /* a mixed-usage bundle */ | |
1621 | int i, j, nrec; | |
1622 | const char ** dd; | |
1623 | int * ddl; | |
1624 | ||
1625 | for(nrec = 0; state->dane_data_len[nrec]; ) nrec++; | |
1626 | nrec++; | |
1627 | ||
1628 | dd = store_get(nrec * sizeof(uschar *)); | |
1629 | ddl = store_get(nrec * sizeof(int)); | |
1630 | nrec--; | |
1631 | ||
1632 | if ((rc = dane_state_init(&s, 0))) | |
1633 | goto tlsa_prob; | |
1634 | ||
1635 | for (usage = DANESSL_USAGE_DANE_EE; | |
1636 | usage >= DANESSL_USAGE_DANE_TA; usage--) | |
1637 | { /* take records with this usage */ | |
1638 | for (j = i = 0; i < nrec; i++) | |
1639 | if (state->dane_data[i][0] == usage) | |
1640 | { | |
1641 | dd[j] = state->dane_data[i]; | |
1642 | ddl[j++] = state->dane_data_len[i]; | |
1643 | } | |
1644 | if (j) | |
1645 | { | |
1646 | dd[j] = NULL; | |
1647 | ddl[j] = 0; | |
1648 | ||
1649 | if ((rc = dane_raw_tlsa(s, &r, (char * const *)dd, ddl, 1, 0))) | |
1650 | goto tlsa_prob; | |
1651 | ||
1652 | if ((rc = dane_verify_crt_raw(s, certlist, lsize, | |
1653 | gnutls_certificate_type_get(state->session), | |
1654 | r, 0, | |
1655 | usage == DANESSL_USAGE_DANE_EE | |
1656 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1657 | &verify))) | |
1658 | { | |
1659 | DEBUG(D_tls) | |
1660 | debug_printf("TLSA record problem: %s\n", dane_strerror(rc)); | |
1661 | } | |
1662 | else if (verify == 0) /* verification passed */ | |
1663 | { | |
1664 | usage = 1 << usage; | |
1665 | break; | |
1666 | } | |
1667 | } | |
1668 | } | |
899b8bbc | 1669 | |
94c13285 JH |
1670 | if (rc) goto tlsa_prob; |
1671 | } | |
1672 | else | |
1673 | # endif | |
899b8bbc | 1674 | { |
94c13285 JH |
1675 | if ( (rc = dane_state_init(&s, 0)) |
1676 | || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len, | |
1677 | 1, 0)) | |
1678 | || (rc = dane_verify_crt_raw(s, certlist, lsize, | |
1679 | gnutls_certificate_type_get(state->session), | |
1680 | r, 0, | |
1681 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION | |
1682 | usage == (1 << DANESSL_USAGE_DANE_EE) | |
1683 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1684 | # else | |
1685 | 0, | |
1686 | # endif | |
1687 | &verify)) | |
1688 | ) | |
1689 | goto tlsa_prob; | |
899b8bbc | 1690 | } |
94c13285 JH |
1691 | |
1692 | if (verify != 0) /* verification failed */ | |
899b8bbc JH |
1693 | { |
1694 | gnutls_datum_t str; | |
1695 | (void) dane_verification_status_print(verify, &str, 0); | |
1696 | *errstr = US str.data; /* don't bother to free */ | |
1697 | goto badcert; | |
1698 | } | |
1699 | state->peer_dane_verified = TRUE; | |
28646fa9 | 1700 | |
94c13285 JH |
1701 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1702 | /* If a TA-mode TLSA record was used for verification we must additionally | |
1703 | verify the CA chain and the cert name. For EE-mode, skip it. */ | |
28646fa9 | 1704 | |
94c13285 JH |
1705 | if (usage & (1 << DANESSL_USAGE_DANE_EE)) |
1706 | # endif | |
28646fa9 JH |
1707 | { |
1708 | state->peer_cert_verified = TRUE; | |
1709 | goto goodcert; | |
1710 | } | |
899b8bbc JH |
1711 | } |
1712 | #endif | |
1713 | ||
17c76198 | 1714 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
899b8bbc | 1715 | } |
e6060e2c | 1716 | |
899b8bbc | 1717 | /* Handle the result of verification. INVALID is set if any others are. */ |
059ec3d9 | 1718 | |
28646fa9 | 1719 | if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) |
17c76198 PP |
1720 | { |
1721 | state->peer_cert_verified = FALSE; | |
cf0c6164 JH |
1722 | if (!*errstr) |
1723 | *errstr = verify & GNUTLS_CERT_REVOKED | |
1724 | ? US"certificate revoked" : US"certificate invalid"; | |
059ec3d9 | 1725 | |
17c76198 | 1726 | DEBUG(D_tls) |
e51c7be2 | 1727 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1728 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1729 | |
e51c7be2 | 1730 | if (state->verify_requirement >= VERIFY_REQUIRED) |
899b8bbc | 1731 | goto badcert; |
17c76198 | 1732 | DEBUG(D_tls) |
4789da3a | 1733 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1734 | } |
e51c7be2 | 1735 | |
17c76198 PP |
1736 | else |
1737 | { | |
aa2a70ba | 1738 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1739 | { |
1740 | int sep = 0; | |
55414b25 | 1741 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 | 1742 | uschar * name; |
76075bb5 | 1743 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) |
e51c7be2 JH |
1744 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) |
1745 | break; | |
1746 | if (!name) | |
1747 | { | |
1748 | DEBUG(D_tls) | |
1749 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba | 1750 | if (state->verify_requirement >= VERIFY_REQUIRED) |
899b8bbc | 1751 | goto badcert; |
aa2a70ba | 1752 | return TRUE; |
e51c7be2 JH |
1753 | } |
1754 | } | |
17c76198 | 1755 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1756 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1757 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1758 | } |
059ec3d9 | 1759 | |
28646fa9 JH |
1760 | goodcert: |
1761 | state->tlsp->peerdn = state->peerdn; | |
1762 | return TRUE; | |
899b8bbc | 1763 | |
b83314e3 | 1764 | #ifdef SUPPORT_DANE |
94c13285 JH |
1765 | tlsa_prob: |
1766 | *errstr = string_sprintf("TLSA record problem: %s", dane_strerror(rc)); | |
b83314e3 JH |
1767 | #endif |
1768 | ||
899b8bbc JH |
1769 | badcert: |
1770 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1771 | return FALSE; | |
17c76198 | 1772 | } |
059ec3d9 | 1773 | |
17c76198 PP |
1774 | |
1775 | ||
1776 | ||
1777 | /* ------------------------------------------------------------------------ */ | |
1778 | /* Callbacks */ | |
1779 | ||
1780 | /* Logging function which can be registered with | |
1781 | * gnutls_global_set_log_function() | |
1782 | * gnutls_global_set_log_level() 0..9 | |
1783 | */ | |
af3498d6 | 1784 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1785 | static void |
17c76198 | 1786 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1787 | { |
8c79eebf PP |
1788 | size_t len = strlen(message); |
1789 | if (len < 1) | |
1790 | { | |
1791 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1792 | return; | |
1793 | } | |
1794 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1795 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1796 | } |
af3498d6 | 1797 | #endif |
059ec3d9 | 1798 | |
059ec3d9 | 1799 | |
17c76198 PP |
1800 | /* Called after client hello, should handle SNI work. |
1801 | This will always set tls_sni (state->received_sni) if available, | |
1802 | and may trigger presenting different certificates, | |
1803 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1804 | |
17c76198 PP |
1805 | Should be registered with |
1806 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1807 | |
17c76198 PP |
1808 | "This callback must return 0 on success or a gnutls error code to terminate the |
1809 | handshake.". | |
059ec3d9 | 1810 | |
17c76198 PP |
1811 | For inability to get SNI information, we return 0. |
1812 | We only return non-zero if re-setup failed. | |
817d9f57 | 1813 | Only used for server-side TLS. |
17c76198 | 1814 | */ |
44bbabb5 | 1815 | |
17c76198 PP |
1816 | static int |
1817 | exim_sni_handling_cb(gnutls_session_t session) | |
1818 | { | |
1819 | char sni_name[MAX_HOST_LEN]; | |
1820 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1821 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1822 | unsigned int sni_type; |
1823 | int rc, old_pool; | |
cf0c6164 | 1824 | uschar * dummy_errstr; |
17c76198 PP |
1825 | |
1826 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1827 | if (rc != GNUTLS_E_SUCCESS) |
1828 | { | |
1829 | DEBUG(D_tls) { | |
1830 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1831 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1832 | else | |
1833 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1834 | gnutls_strerror(rc), rc); | |
cf0c6164 | 1835 | } |
b34fc30c PP |
1836 | return 0; |
1837 | } | |
1838 | ||
17c76198 PP |
1839 | if (sni_type != GNUTLS_NAME_DNS) |
1840 | { | |
1841 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1842 | return 0; | |
1843 | } | |
44bbabb5 | 1844 | |
17c76198 PP |
1845 | /* We now have a UTF-8 string in sni_name */ |
1846 | old_pool = store_pool; | |
1847 | store_pool = POOL_PERM; | |
1848 | state->received_sni = string_copyn(US sni_name, data_len); | |
1849 | store_pool = old_pool; | |
1850 | ||
1851 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1852 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1853 | |
1854 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1855 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1856 | ||
1857 | if (!state->trigger_sni_changes) | |
1858 | return 0; | |
1859 | ||
cf0c6164 | 1860 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
1861 | { |
1862 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1863 | been offered. The best we can do now is abort. */ | |
1864 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1865 | } | |
1866 | ||
cf0c6164 | 1867 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
1868 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
1869 | ||
1870 | return 0; | |
059ec3d9 PH |
1871 | } |
1872 | ||
1873 | ||
1874 | ||
f2de3a33 | 1875 | #ifndef DISABLE_OCSP |
44662487 JH |
1876 | |
1877 | static int | |
1878 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1879 | gnutls_datum_t * ocsp_response) | |
1880 | { | |
1881 | int ret; | |
47195144 | 1882 | DEBUG(D_tls) debug_printf("OCSP stapling callback: %s\n", US ptr); |
44662487 | 1883 | |
44662487 JH |
1884 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1885 | { | |
1886 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
5903c6ff | 1887 | CS ptr); |
018058b2 | 1888 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1889 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1890 | } | |
1891 | ||
018058b2 | 1892 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1893 | return 0; |
1894 | } | |
1895 | ||
1896 | #endif | |
1897 | ||
1898 | ||
0cbf2b82 | 1899 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1900 | /* |
1901 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1902 | for an exim TLS connection (either direction), raising a tls:cert event |
1903 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1904 | can deny verification. |
1905 | ||
1906 | Return 0 for the handshake to continue or non-zero to terminate. | |
1907 | */ | |
1908 | ||
1909 | static int | |
723fe533 | 1910 | verify_cb(gnutls_session_t session) |
a7538db1 | 1911 | { |
27f19eb4 | 1912 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1913 | unsigned int cert_list_size = 0; |
1914 | gnutls_x509_crt_t crt; | |
1915 | int rc; | |
b30275b8 | 1916 | uschar * yield; |
a7538db1 JH |
1917 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1918 | ||
1919 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1920 | if (cert_list) | |
1921 | while (cert_list_size--) | |
1922 | { | |
1923 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1924 | if (rc != GNUTLS_E_SUCCESS) | |
1925 | { | |
1926 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1927 | cert_list_size, gnutls_strerror(rc)); | |
1928 | break; | |
1929 | } | |
1930 | ||
1931 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1932 | if ((yield = event_raise(state->event_action, |
1933 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1934 | { |
1935 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1936 | "SSL verify denied by event-action: depth=%d: %s", |
1937 | cert_list_size, yield); | |
a7538db1 JH |
1938 | return 1; /* reject */ |
1939 | } | |
1940 | state->tlsp->peercert = NULL; | |
1941 | } | |
1942 | ||
1943 | return 0; | |
1944 | } | |
1945 | ||
1946 | #endif | |
44662487 JH |
1947 | |
1948 | ||
17c76198 PP |
1949 | |
1950 | /* ------------------------------------------------------------------------ */ | |
1951 | /* Exported functions */ | |
1952 | ||
1953 | ||
1954 | ||
1955 | ||
059ec3d9 PH |
1956 | /************************************************* |
1957 | * Start a TLS session in a server * | |
1958 | *************************************************/ | |
1959 | ||
1960 | /* This is called when Exim is running as a server, after having received | |
1961 | the STARTTLS command. It must respond to that command, and then negotiate | |
1962 | a TLS session. | |
1963 | ||
1964 | Arguments: | |
83da1223 | 1965 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 1966 | errstr pointer to error string |
059ec3d9 PH |
1967 | |
1968 | Returns: OK on success | |
1969 | DEFER for errors before the start of the negotiation | |
4c04137d | 1970 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
1971 | continue running. |
1972 | */ | |
1973 | ||
1974 | int | |
cf0c6164 | 1975 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
1976 | { |
1977 | int rc; | |
cf0c6164 | 1978 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
1979 | |
1980 | /* Check for previous activation */ | |
817d9f57 | 1981 | if (tls_in.active >= 0) |
059ec3d9 | 1982 | { |
cf0c6164 | 1983 | tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); |
925ac8e4 | 1984 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
1985 | return FAIL; |
1986 | } | |
1987 | ||
1988 | /* Initialize the library. If it fails, it will already have logged the error | |
1989 | and sent an SMTP response. */ | |
1990 | ||
17c76198 | 1991 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1992 | |
cf0c6164 | 1993 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 1994 | NULL, tls_verify_certificates, tls_crl, |
cf0c6164 | 1995 | require_ciphers, &state, errstr)) != OK) return rc; |
059ec3d9 | 1996 | |
059ec3d9 PH |
1997 | /* If this is a host for which certificate verification is mandatory or |
1998 | optional, set up appropriately. */ | |
1999 | ||
059ec3d9 | 2000 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 2001 | { |
e51c7be2 JH |
2002 | DEBUG(D_tls) |
2003 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
2004 | state->verify_requirement = VERIFY_REQUIRED; |
2005 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
2006 | } | |
059ec3d9 | 2007 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 2008 | { |
e51c7be2 JH |
2009 | DEBUG(D_tls) |
2010 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
2011 | state->verify_requirement = VERIFY_OPTIONAL; |
2012 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
2013 | } | |
2014 | else | |
2015 | { | |
e51c7be2 JH |
2016 | DEBUG(D_tls) |
2017 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
2018 | state->verify_requirement = VERIFY_NONE; |
2019 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
2020 | } | |
059ec3d9 | 2021 | |
0cbf2b82 | 2022 | #ifndef DISABLE_EVENT |
723fe533 JH |
2023 | if (event_action) |
2024 | { | |
2025 | state->event_action = event_action; | |
2026 | gnutls_session_set_ptr(state->session, state); | |
2027 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
2028 | } | |
2029 | #endif | |
2030 | ||
17c76198 PP |
2031 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
2032 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 2033 | |
17c76198 PP |
2034 | gnutls_handshake_set_post_client_hello_function(state->session, |
2035 | exim_sni_handling_cb); | |
059ec3d9 PH |
2036 | |
2037 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2038 | on connection, where outputting anything now upsets the clients and tends to | |
2039 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2040 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2041 | mode, the fflush() happens when smtp_getc() is called. */ | |
2042 | ||
817d9f57 | 2043 | if (!state->tlsp->on_connect) |
059ec3d9 | 2044 | { |
925ac8e4 | 2045 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 2046 | fflush(smtp_out); |
059ec3d9 PH |
2047 | } |
2048 | ||
2049 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
2050 | that the GnuTLS library doesn't. */ | |
2051 | ||
17c76198 | 2052 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
2053 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
2054 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
2055 | state->fd_in = fileno(smtp_in); |
2056 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
2057 | |
2058 | sigalrm_seen = FALSE; | |
2059 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 2060 | do |
17c76198 | 2061 | rc = gnutls_handshake(state->session); |
157a7880 | 2062 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
2063 | alarm(0); |
2064 | ||
17c76198 | 2065 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 2066 | { |
059ec3d9 PH |
2067 | /* It seems that, except in the case of a timeout, we have to close the |
2068 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
2069 | until the server times out. */ | |
2070 | ||
60d10ce7 | 2071 | if (sigalrm_seen) |
ad7fc6eb | 2072 | { |
cf0c6164 | 2073 | tls_error(US"gnutls_handshake", "timed out", NULL, errstr); |
ad7fc6eb JH |
2074 | gnutls_db_remove_session(state->session); |
2075 | } | |
60d10ce7 | 2076 | else |
059ec3d9 | 2077 | { |
cf0c6164 | 2078 | tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); |
f5d25c2b | 2079 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 2080 | gnutls_deinit(state->session); |
ed62aae3 | 2081 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 2082 | millisleep(500); |
ad7fc6eb | 2083 | shutdown(state->fd_out, SHUT_WR); |
60d10ce7 | 2084 | for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ |
f1e894f3 PH |
2085 | (void)fclose(smtp_out); |
2086 | (void)fclose(smtp_in); | |
60d10ce7 | 2087 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
2088 | } |
2089 | ||
2090 | return FAIL; | |
2091 | } | |
2092 | ||
2093 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
2094 | ||
17c76198 PP |
2095 | /* Verify after the fact */ |
2096 | ||
899b8bbc | 2097 | if (!verify_certificate(state, errstr)) |
059ec3d9 | 2098 | { |
9d1c15ef | 2099 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 2100 | { |
cf0c6164 | 2101 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 2102 | return FAIL; |
17c76198 | 2103 | } |
9d1c15ef JH |
2104 | DEBUG(D_tls) |
2105 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 2106 | *errstr); |
059ec3d9 PH |
2107 | } |
2108 | ||
17c76198 PP |
2109 | /* Figure out peer DN, and if authenticated, etc. */ |
2110 | ||
cf0c6164 | 2111 | if ((rc = peer_status(state, NULL)) != OK) return rc; |
17c76198 PP |
2112 | |
2113 | /* Sets various Exim expansion variables; always safe within server */ | |
2114 | ||
9d1c15ef | 2115 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
2116 | |
2117 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2118 | and initialize appropriately. */ | |
2119 | ||
17c76198 | 2120 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
2121 | |
2122 | receive_getc = tls_getc; | |
0d81dabc | 2123 | receive_getbuf = tls_getbuf; |
584e96c6 | 2124 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2125 | receive_ungetc = tls_ungetc; |
2126 | receive_feof = tls_feof; | |
2127 | receive_ferror = tls_ferror; | |
58eb016e | 2128 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2129 | |
059ec3d9 PH |
2130 | return OK; |
2131 | } | |
2132 | ||
2133 | ||
2134 | ||
2135 | ||
aa2a70ba JH |
2136 | static void |
2137 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
2138 | smtp_transport_options_block * ob) | |
2139 | { | |
5130845b | 2140 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 2141 | { |
4af0d74a | 2142 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 2143 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2144 | string_domain_utf8_to_alabel(host->name, NULL); |
2145 | #else | |
2146 | host->name; | |
2147 | #endif | |
aa2a70ba JH |
2148 | DEBUG(D_tls) |
2149 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
2150 | state->exp_tls_verify_cert_hostnames); | |
2151 | } | |
2152 | } | |
aa2a70ba JH |
2153 | |
2154 | ||
899b8bbc JH |
2155 | |
2156 | ||
2157 | #ifdef SUPPORT_DANE | |
2158 | /* Given our list of RRs from the TLSA lookup, build a lookup block in | |
2159 | GnuTLS-DANE's preferred format. Hang it on the state str for later | |
2160 | use in DANE verification. | |
2161 | ||
2162 | We point at the dnsa data not copy it, so it must remain valid until | |
2163 | after verification is done.*/ | |
2164 | ||
3674140c | 2165 | static BOOL |
899b8bbc JH |
2166 | dane_tlsa_load(exim_gnutls_state_st * state, dns_answer * dnsa) |
2167 | { | |
2168 | dns_record * rr; | |
2169 | dns_scan dnss; | |
2170 | int i; | |
2171 | const char ** dane_data; | |
2172 | int * dane_data_len; | |
2173 | ||
2174 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS), i = 1; | |
2175 | rr; | |
2176 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
2177 | ) if (rr->type == T_TLSA) i++; | |
2178 | ||
2179 | dane_data = store_get(i * sizeof(uschar *)); | |
2180 | dane_data_len = store_get(i * sizeof(int)); | |
2181 | ||
2182 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS), i = 0; | |
2183 | rr; | |
2184 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
2185 | ) if (rr->type == T_TLSA) | |
2186 | { | |
2187 | const uschar * p = rr->data; | |
3674140c JH |
2188 | uint8_t usage = p[0], sel = p[1], type = p[2]; |
2189 | ||
2190 | DEBUG(D_tls) | |
2191 | debug_printf("TLSA: %d %d %d size %d\n", usage, sel, type, rr->size); | |
2192 | ||
94c13285 JH |
2193 | if ( (usage != DANESSL_USAGE_DANE_TA && usage != DANESSL_USAGE_DANE_EE) |
2194 | || (sel != 0 && sel != 1) | |
2195 | ) | |
2196 | continue; | |
3674140c JH |
2197 | switch(type) |
2198 | { | |
2199 | case 0: /* Full: cannot check at present */ | |
2200 | break; | |
2201 | case 1: if (rr->size != 3 + 256/8) continue; /* sha2-256 */ | |
2202 | break; | |
2203 | case 2: if (rr->size != 3 + 512/8) continue; /* sha2-512 */ | |
2204 | break; | |
2205 | default: continue; | |
2206 | } | |
899b8bbc JH |
2207 | |
2208 | tls_out.tlsa_usage |= 1<<usage; | |
2209 | dane_data[i] = p; | |
2210 | dane_data_len[i++] = rr->size; | |
2211 | } | |
3674140c JH |
2212 | |
2213 | if (!i) return FALSE; | |
2214 | ||
899b8bbc JH |
2215 | dane_data[i] = NULL; |
2216 | dane_data_len[i] = 0; | |
2217 | ||
2218 | state->dane_data = (char * const *)dane_data; | |
2219 | state->dane_data_len = dane_data_len; | |
3674140c | 2220 | return TRUE; |
899b8bbc JH |
2221 | } |
2222 | #endif | |
2223 | ||
2224 | ||
2225 | ||
059ec3d9 PH |
2226 | /************************************************* |
2227 | * Start a TLS session in a client * | |
2228 | *************************************************/ | |
2229 | ||
2230 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2231 | ||
2232 | Arguments: | |
2233 | fd the fd of the connection | |
2234 | host connected host (for messages) | |
83da1223 | 2235 | addr the first address (not used) |
a7538db1 | 2236 | tb transport (always smtp) |
899b8bbc JH |
2237 | tlsa_dnsa non-NULL, either request or require dane for this host, and |
2238 | a TLSA record found. Therefore, dane verify required. | |
2239 | Which implies cert must be requested and supplied, dane | |
2240 | verify must pass, and cert verify irrelevant (incl. | |
2241 | hostnames), and (caller handled) require_tls | |
cf0c6164 JH |
2242 | errstr error string pointer |
2243 | ||
059ec3d9 PH |
2244 | Returns: OK/DEFER/FAIL (because using common functions), |
2245 | but for a client, DEFER and FAIL have the same meaning | |
2246 | */ | |
2247 | ||
2248 | int | |
17c76198 | 2249 | tls_client_start(int fd, host_item *host, |
f5d78688 | 2250 | address_item *addr ARG_UNUSED, |
cf0c6164 | 2251 | transport_instance * tb, |
0e66b3b6 | 2252 | #ifdef EXPERIMENTAL_DANE |
899b8bbc | 2253 | dns_answer * tlsa_dnsa, |
0e66b3b6 | 2254 | #endif |
cf0c6164 | 2255 | uschar ** errstr) |
059ec3d9 | 2256 | { |
a7538db1 JH |
2257 | smtp_transport_options_block *ob = |
2258 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 2259 | int rc; |
899b8bbc | 2260 | exim_gnutls_state_st * state = NULL; |
f2de3a33 | 2261 | #ifndef DISABLE_OCSP |
5130845b JH |
2262 | BOOL require_ocsp = |
2263 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 2264 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 2265 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 2266 | #endif |
059ec3d9 | 2267 | |
17c76198 | 2268 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 2269 | |
65867078 JH |
2270 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
2271 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
cf0c6164 | 2272 | ob->tls_require_ciphers, &state, errstr)) != OK) |
2b4a568d | 2273 | return rc; |
059ec3d9 | 2274 | |
54c90be1 | 2275 | { |
65867078 JH |
2276 | int dh_min_bits = ob->tls_dh_min_bits; |
2277 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2278 | { | |
2279 | DEBUG(D_tls) | |
2280 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2281 | " clamping %d up to %d\n", | |
2282 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2283 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2284 | } | |
54c90be1 | 2285 | |
65867078 JH |
2286 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2287 | " acceptable bits to %d\n", | |
2288 | dh_min_bits); | |
2289 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2290 | } | |
83da1223 | 2291 | |
94431adb | 2292 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2293 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2294 | the specified host patterns if one of them is defined */ | |
2295 | ||
899b8bbc | 2296 | #ifdef SUPPORT_DANE |
3674140c | 2297 | if (tlsa_dnsa && dane_tlsa_load(state, tlsa_dnsa)) |
899b8bbc JH |
2298 | { |
2299 | DEBUG(D_tls) | |
2300 | debug_printf("TLS: server certificate DANE required.\n"); | |
2301 | state->verify_requirement = VERIFY_DANE; | |
2302 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
899b8bbc JH |
2303 | } |
2304 | else | |
2305 | #endif | |
2306 | if ( ( state->exp_tls_verify_certificates | |
2307 | && !ob->tls_verify_hosts | |
2308 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2309 | ) | |
2310 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK | |
2311 | ) | |
17c76198 | 2312 | { |
aa2a70ba | 2313 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2314 | DEBUG(D_tls) |
2315 | debug_printf("TLS: server certificate verification required.\n"); | |
2316 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2317 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2318 | } | |
5130845b | 2319 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2320 | { |
aa2a70ba | 2321 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2322 | DEBUG(D_tls) |
2323 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2324 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2325 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2326 | } | |
2327 | else | |
2328 | { | |
e51c7be2 JH |
2329 | DEBUG(D_tls) |
2330 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2331 | state->verify_requirement = VERIFY_NONE; |
2332 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2333 | } |
059ec3d9 | 2334 | |
f2de3a33 JH |
2335 | #ifndef DISABLE_OCSP |
2336 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2337 | if (request_ocsp) |
9d1c15ef JH |
2338 | { |
2339 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2340 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2341 | NULL, 0, NULL)) != OK) | |
9d1c15ef | 2342 | return tls_error(US"cert-status-req", |
cf0c6164 | 2343 | gnutls_strerror(rc), state->host, errstr); |
44662487 | 2344 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2345 | } |
2b4a568d JH |
2346 | #endif |
2347 | ||
0cbf2b82 | 2348 | #ifndef DISABLE_EVENT |
774ef2d7 | 2349 | if (tb->event_action) |
a7538db1 | 2350 | { |
774ef2d7 | 2351 | state->event_action = tb->event_action; |
a7538db1 | 2352 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2353 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2354 | } |
2355 | #endif | |
2356 | ||
27f19eb4 | 2357 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2358 | state->fd_in = fd; |
2359 | state->fd_out = fd; | |
059ec3d9 | 2360 | |
9d1c15ef | 2361 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2362 | /* There doesn't seem to be a built-in timeout on connection. */ |
2363 | ||
2364 | sigalrm_seen = FALSE; | |
65867078 | 2365 | alarm(ob->command_timeout); |
17c76198 | 2366 | do |
17c76198 | 2367 | rc = gnutls_handshake(state->session); |
f1fed05b | 2368 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
2369 | alarm(0); |
2370 | ||
4fe99a6c | 2371 | if (rc != GNUTLS_E_SUCCESS) |
60d10ce7 JH |
2372 | if (sigalrm_seen) |
2373 | { | |
2374 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
cf0c6164 | 2375 | return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); |
60d10ce7 JH |
2376 | } |
2377 | else | |
cf0c6164 | 2378 | return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); |
4fe99a6c | 2379 | |
17c76198 | 2380 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2381 | |
17c76198 | 2382 | /* Verify late */ |
059ec3d9 | 2383 | |
899b8bbc | 2384 | if (!verify_certificate(state, errstr)) |
cf0c6164 | 2385 | return tls_error(US"certificate verification failed", *errstr, state->host, errstr); |
059ec3d9 | 2386 | |
f2de3a33 | 2387 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2388 | if (require_ocsp) |
2389 | { | |
2390 | DEBUG(D_tls) | |
2391 | { | |
2392 | gnutls_datum_t stapling; | |
2393 | gnutls_ocsp_resp_t resp; | |
2394 | gnutls_datum_t printed; | |
2395 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2396 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2397 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2398 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2399 | ) | |
2400 | { | |
65867078 | 2401 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2402 | gnutls_free(printed.data); |
2403 | } | |
2404 | else | |
cf0c6164 | 2405 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host, errstr); |
2b4a568d JH |
2406 | } |
2407 | ||
2b4a568d | 2408 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2409 | { |
2410 | tls_out.ocsp = OCSP_FAILED; | |
cf0c6164 | 2411 | return tls_error(US"certificate status check failed", NULL, state->host, errstr); |
018058b2 | 2412 | } |
2b4a568d | 2413 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2414 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2415 | } |
2416 | #endif | |
2417 | ||
17c76198 | 2418 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2419 | |
cf0c6164 | 2420 | if ((rc = peer_status(state, errstr)) != OK) |
2b4a568d | 2421 | return rc; |
059ec3d9 | 2422 | |
4fe99a6c | 2423 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2424 | |
9d1c15ef | 2425 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2426 | |
059ec3d9 PH |
2427 | return OK; |
2428 | } | |
2429 | ||
2430 | ||
2431 | ||
17c76198 | 2432 | |
059ec3d9 | 2433 | /************************************************* |
17c76198 | 2434 | * Close down a TLS session * |
059ec3d9 PH |
2435 | *************************************************/ |
2436 | ||
17c76198 PP |
2437 | /* This is also called from within a delivery subprocess forked from the |
2438 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2439 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2440 | |
17c76198 PP |
2441 | Arguments: TRUE if gnutls_bye is to be called |
2442 | Returns: nothing | |
059ec3d9 PH |
2443 | */ |
2444 | ||
17c76198 | 2445 | void |
817d9f57 | 2446 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2447 | { |
817d9f57 | 2448 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2449 | |
389ca47a | 2450 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2451 | |
2452 | if (shutdown) | |
2453 | { | |
f5723109 | 2454 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); |
17c76198 PP |
2455 | gnutls_bye(state->session, GNUTLS_SHUT_WR); |
2456 | } | |
2457 | ||
2458 | gnutls_deinit(state->session); | |
ed62aae3 HSHR |
2459 | gnutls_certificate_free_credentials(state->x509_cred); |
2460 | ||
17c76198 | 2461 | |
389ca47a | 2462 | state->tlsp->active = -1; |
17c76198 PP |
2463 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2464 | ||
2465 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2466 | { | |
2467 | gnutls_global_deinit(); | |
2468 | exim_gnutls_base_init_done = FALSE; | |
2469 | } | |
059ec3d9 PH |
2470 | } |
2471 | ||
2472 | ||
2473 | ||
17c76198 | 2474 | |
0d81dabc JH |
2475 | static BOOL |
2476 | tls_refill(unsigned lim) | |
2477 | { | |
2478 | exim_gnutls_state_st * state = &state_server; | |
2479 | ssize_t inbytes; | |
2480 | ||
2481 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2482 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2483 | ||
f1fed05b | 2484 | sigalrm_seen = FALSE; |
0d81dabc JH |
2485 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); |
2486 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2487 | MIN(ssl_xfer_buffer_size, lim)); | |
2488 | alarm(0); | |
2489 | ||
2490 | /* Timeouts do not get this far; see command_timeout_handler(). | |
2491 | A zero-byte return appears to mean that the TLS session has been | |
2492 | closed down, not that the socket itself has been closed down. Revert to | |
2493 | non-TLS handling. */ | |
2494 | ||
2495 | if (sigalrm_seen) | |
2496 | { | |
2497 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
2498 | state->xfer_error = 1; | |
2499 | return FALSE; | |
2500 | } | |
2501 | ||
2502 | else if (inbytes == 0) | |
2503 | { | |
2504 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2505 | ||
2506 | receive_getc = smtp_getc; | |
2507 | receive_getbuf = smtp_getbuf; | |
2508 | receive_get_cache = smtp_get_cache; | |
2509 | receive_ungetc = smtp_ungetc; | |
2510 | receive_feof = smtp_feof; | |
2511 | receive_ferror = smtp_ferror; | |
2512 | receive_smtp_buffered = smtp_buffered; | |
2513 | ||
2514 | gnutls_deinit(state->session); | |
2515 | gnutls_certificate_free_credentials(state->x509_cred); | |
2516 | ||
2517 | state->session = NULL; | |
2518 | state->tlsp->active = -1; | |
2519 | state->tlsp->bits = 0; | |
2520 | state->tlsp->certificate_verified = FALSE; | |
2521 | tls_channelbinding_b64 = NULL; | |
2522 | state->tlsp->cipher = NULL; | |
2523 | state->tlsp->peercert = NULL; | |
2524 | state->tlsp->peerdn = NULL; | |
2525 | ||
2526 | return FALSE; | |
2527 | } | |
2528 | ||
2529 | /* Handle genuine errors */ | |
2530 | ||
2531 | else if (inbytes < 0) | |
2532 | { | |
2533 | record_io_error(state, (int) inbytes, US"recv", NULL); | |
2534 | state->xfer_error = 1; | |
2535 | return FALSE; | |
2536 | } | |
2537 | #ifndef DISABLE_DKIM | |
2538 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
2539 | #endif | |
2540 | state->xfer_buffer_hwm = (int) inbytes; | |
2541 | state->xfer_buffer_lwm = 0; | |
2542 | return TRUE; | |
2543 | } | |
2544 | ||
059ec3d9 PH |
2545 | /************************************************* |
2546 | * TLS version of getc * | |
2547 | *************************************************/ | |
2548 | ||
2549 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2550 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2551 | Only used by the server-side TLS. |
059ec3d9 | 2552 | |
17c76198 PP |
2553 | This feeds DKIM and should be used for all message-body reads. |
2554 | ||
bd8fbe36 | 2555 | Arguments: lim Maximum amount to read/bufffer |
059ec3d9 PH |
2556 | Returns: the next character or EOF |
2557 | */ | |
2558 | ||
2559 | int | |
bd8fbe36 | 2560 | tls_getc(unsigned lim) |
059ec3d9 | 2561 | { |
0d81dabc | 2562 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 2563 | |
0d81dabc JH |
2564 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2565 | if (!tls_refill(lim)) | |
2566 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 2567 | |
0d81dabc | 2568 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2569 | |
0d81dabc JH |
2570 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
2571 | } | |
059ec3d9 | 2572 | |
0d81dabc JH |
2573 | uschar * |
2574 | tls_getbuf(unsigned * len) | |
2575 | { | |
2576 | exim_gnutls_state_st * state = &state_server; | |
2577 | unsigned size; | |
2578 | uschar * buf; | |
059ec3d9 | 2579 | |
0d81dabc JH |
2580 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2581 | if (!tls_refill(*len)) | |
059ec3d9 | 2582 | { |
0d81dabc JH |
2583 | if (!state->xfer_error) return smtp_getbuf(len); |
2584 | *len = 0; | |
2585 | return NULL; | |
059ec3d9 | 2586 | } |
059ec3d9 | 2587 | |
0d81dabc JH |
2588 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
2589 | size = *len; | |
2590 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
2591 | state->xfer_buffer_lwm += size; | |
2592 | *len = size; | |
2593 | return buf; | |
059ec3d9 PH |
2594 | } |
2595 | ||
0d81dabc | 2596 | |
584e96c6 JH |
2597 | void |
2598 | tls_get_cache() | |
2599 | { | |
9960d1e5 | 2600 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2601 | exim_gnutls_state_st * state = &state_server; |
2602 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2603 | if (n > 0) | |
2604 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2605 | #endif |
9960d1e5 | 2606 | } |
584e96c6 | 2607 | |
059ec3d9 | 2608 | |
925ac8e4 JH |
2609 | BOOL |
2610 | tls_could_read(void) | |
2611 | { | |
2612 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
2613 | || gnutls_record_check_pending(state_server.session) > 0; | |
2614 | } | |
2615 | ||
2616 | ||
059ec3d9 | 2617 | |
17c76198 | 2618 | |
059ec3d9 PH |
2619 | /************************************************* |
2620 | * Read bytes from TLS channel * | |
2621 | *************************************************/ | |
2622 | ||
17c76198 PP |
2623 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2624 | then the caller must feed DKIM. | |
817d9f57 | 2625 | |
059ec3d9 PH |
2626 | Arguments: |
2627 | buff buffer of data | |
2628 | len size of buffer | |
2629 | ||
2630 | Returns: the number of bytes read | |
2631 | -1 after a failed read | |
2632 | */ | |
2633 | ||
2634 | int | |
817d9f57 | 2635 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2636 | { |
817d9f57 | 2637 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2638 | ssize_t inbytes; |
059ec3d9 | 2639 | |
17c76198 PP |
2640 | if (len > INT_MAX) |
2641 | len = INT_MAX; | |
059ec3d9 | 2642 | |
17c76198 PP |
2643 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2644 | DEBUG(D_tls) | |
2645 | debug_printf("*** PROBABLY A BUG *** " \ | |
2646 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2647 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2648 | ||
2649 | DEBUG(D_tls) | |
2650 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2651 | state->session, buff, len); | |
2652 | ||
2653 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2654 | if (inbytes > 0) return inbytes; |
2655 | if (inbytes == 0) | |
2656 | { | |
2657 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2658 | } | |
17c76198 | 2659 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2660 | |
2661 | return -1; | |
2662 | } | |
2663 | ||
2664 | ||
2665 | ||
17c76198 | 2666 | |
059ec3d9 PH |
2667 | /************************************************* |
2668 | * Write bytes down TLS channel * | |
2669 | *************************************************/ | |
2670 | ||
2671 | /* | |
2672 | Arguments: | |
817d9f57 | 2673 | is_server channel specifier |
059ec3d9 PH |
2674 | buff buffer of data |
2675 | len number of bytes | |
925ac8e4 | 2676 | more more data expected soon |
059ec3d9 PH |
2677 | |
2678 | Returns: the number of bytes after a successful write, | |
2679 | -1 after a failed write | |
2680 | */ | |
2681 | ||
2682 | int | |
925ac8e4 | 2683 | tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2684 | { |
17c76198 PP |
2685 | ssize_t outbytes; |
2686 | size_t left = len; | |
817d9f57 | 2687 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
925ac8e4 JH |
2688 | #ifdef SUPPORT_CORK |
2689 | static BOOL corked = FALSE; | |
2690 | ||
2691 | if (more && !corked) gnutls_record_cork(state->session); | |
2692 | #endif | |
2693 | ||
2694 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
2695 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 2696 | |
059ec3d9 PH |
2697 | while (left > 0) |
2698 | { | |
17c76198 PP |
2699 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2700 | buff, left); | |
2701 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2702 | |
17c76198 | 2703 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2704 | if (outbytes < 0) |
2705 | { | |
17c76198 | 2706 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2707 | return -1; |
2708 | } | |
2709 | if (outbytes == 0) | |
2710 | { | |
17c76198 | 2711 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2712 | return -1; |
2713 | } | |
2714 | ||
2715 | left -= outbytes; | |
2716 | buff += outbytes; | |
2717 | } | |
2718 | ||
17c76198 PP |
2719 | if (len > INT_MAX) |
2720 | { | |
2721 | DEBUG(D_tls) | |
2722 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2723 | len); | |
2724 | len = INT_MAX; | |
2725 | } | |
2726 | ||
925ac8e4 JH |
2727 | #ifdef SUPPORT_CORK |
2728 | if (more != corked) | |
2729 | { | |
2730 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
2731 | corked = more; | |
2732 | } | |
2733 | #endif | |
2734 | ||
17c76198 | 2735 | return (int) len; |
059ec3d9 PH |
2736 | } |
2737 | ||
2738 | ||
2739 | ||
17c76198 | 2740 | |
059ec3d9 | 2741 | /************************************************* |
17c76198 | 2742 | * Random number generation * |
059ec3d9 PH |
2743 | *************************************************/ |
2744 | ||
17c76198 PP |
2745 | /* Pseudo-random number generation. The result is not expected to be |
2746 | cryptographically strong but not so weak that someone will shoot themselves | |
2747 | in the foot using it as a nonce in input in some email header scheme or | |
2748 | whatever weirdness they'll twist this into. The result should handle fork() | |
2749 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2750 | |
17c76198 PP |
2751 | Arguments: |
2752 | max range maximum | |
2753 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2754 | */ |
2755 | ||
af3498d6 | 2756 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2757 | int |
2758 | vaguely_random_number(int max) | |
059ec3d9 | 2759 | { |
17c76198 PP |
2760 | unsigned int r; |
2761 | int i, needed_len; | |
2762 | uschar *p; | |
2763 | uschar smallbuf[sizeof(r)]; | |
2764 | ||
2765 | if (max <= 1) | |
2766 | return 0; | |
2767 | ||
2768 | needed_len = sizeof(r); | |
2769 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2770 | * asked for a number less than 10. */ | |
2771 | for (r = max, i = 0; r; ++i) | |
2772 | r >>= 1; | |
2773 | i = (i + 7) / 8; | |
2774 | if (i < needed_len) | |
2775 | needed_len = i; | |
2776 | ||
2777 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2778 | if (i < 0) | |
059ec3d9 | 2779 | { |
17c76198 PP |
2780 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2781 | return vaguely_random_number_fallback(max); | |
2782 | } | |
2783 | r = 0; | |
2784 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2785 | { | |
2786 | r *= 256; | |
2787 | r += *p; | |
059ec3d9 PH |
2788 | } |
2789 | ||
17c76198 PP |
2790 | /* We don't particularly care about weighted results; if someone wants |
2791 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2792 | return r % max; | |
059ec3d9 | 2793 | } |
af3498d6 PP |
2794 | #else /* HAVE_GNUTLS_RND */ |
2795 | int | |
2796 | vaguely_random_number(int max) | |
2797 | { | |
2798 | return vaguely_random_number_fallback(max); | |
2799 | } | |
2800 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2801 | |
36f12725 NM |
2802 | |
2803 | ||
2804 | ||
3375e053 PP |
2805 | /************************************************* |
2806 | * Let tls_require_ciphers be checked at startup * | |
2807 | *************************************************/ | |
2808 | ||
2809 | /* The tls_require_ciphers option, if set, must be something which the | |
2810 | library can parse. | |
2811 | ||
2812 | Returns: NULL on success, or error message | |
2813 | */ | |
2814 | ||
2815 | uschar * | |
2816 | tls_validate_require_cipher(void) | |
2817 | { | |
2818 | int rc; | |
2819 | uschar *expciphers = NULL; | |
2820 | gnutls_priority_t priority_cache; | |
2821 | const char *errpos; | |
cf0c6164 | 2822 | uschar * dummy_errstr; |
3375e053 PP |
2823 | |
2824 | #define validate_check_rc(Label) do { \ | |
2825 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2826 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2827 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2828 | ||
2829 | if (exim_gnutls_base_init_done) | |
2830 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2831 | "already initialised GnuTLS, Exim developer bug"); | |
2832 | ||
a5f239e4 | 2833 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2834 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2835 | { |
2836 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2837 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2838 | } | |
2839 | #endif | |
3375e053 PP |
2840 | rc = gnutls_global_init(); |
2841 | validate_check_rc(US"gnutls_global_init()"); | |
2842 | exim_gnutls_base_init_done = TRUE; | |
2843 | ||
2844 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2845 | return_deinit(NULL); | |
2846 | ||
cf0c6164 JH |
2847 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
2848 | &dummy_errstr)) | |
3375e053 PP |
2849 | return_deinit(US"failed to expand tls_require_ciphers"); |
2850 | ||
2851 | if (!(expciphers && *expciphers)) | |
2852 | return_deinit(NULL); | |
2853 | ||
2854 | DEBUG(D_tls) | |
2855 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2856 | ||
2857 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2858 | validate_check_rc(string_sprintf( | |
2859 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2860 | expciphers, errpos - CS expciphers, errpos)); | |
2861 | ||
2862 | #undef return_deinit | |
2863 | #undef validate_check_rc | |
2864 | gnutls_global_deinit(); | |
2865 | ||
2866 | return NULL; | |
2867 | } | |
2868 | ||
2869 | ||
2870 | ||
2871 | ||
36f12725 NM |
2872 | /************************************************* |
2873 | * Report the library versions. * | |
2874 | *************************************************/ | |
2875 | ||
2876 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2877 | ||
2878 | Arguments: a FILE* to print the results to | |
2879 | Returns: nothing | |
2880 | */ | |
2881 | ||
2882 | void | |
2883 | tls_version_report(FILE *f) | |
2884 | { | |
754a0503 PP |
2885 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2886 | " Runtime: %s\n", | |
2887 | LIBGNUTLS_VERSION, | |
2888 | gnutls_check_version(NULL)); | |
36f12725 NM |
2889 | } |
2890 | ||
2b4a568d JH |
2891 | /* vi: aw ai sw=2 |
2892 | */ | |
059ec3d9 | 2893 | /* End of tls-gnu.c */ |