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> | |
184384c3 | 42 | |
a5f239e4 PP |
43 | /* needed to disable PKCS11 autoload unless requested */ |
44 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
45 | # include <gnutls/pkcs11.h> | |
76075bb5 | 46 | # define SUPPORT_PARAM_TO_PK_BITS |
a5f239e4 | 47 | #endif |
7e07527a JH |
48 | #if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) |
49 | # warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" | |
50 | # define DISABLE_OCSP | |
51 | #endif | |
0cbf2b82 | 52 | #if GNUTLS_VERSION_NUMBER < 0x020a00 && !defined(DISABLE_EVENT) |
774ef2d7 | 53 | # warning "GnuTLS library version too old; tls:cert event unsupported" |
0cbf2b82 | 54 | # define DISABLE_EVENT |
a7538db1 | 55 | #endif |
a7fec7a7 JH |
56 | #if GNUTLS_VERSION_NUMBER >= 0x030306 |
57 | # define SUPPORT_CA_DIR | |
58 | #else | |
59 | # undef SUPPORT_CA_DIR | |
60 | #endif | |
11a04b5a | 61 | #if GNUTLS_VERSION_NUMBER >= 0x030014 |
cb1d7830 JH |
62 | # define SUPPORT_SYSDEFAULT_CABUNDLE |
63 | #endif | |
184384c3 JH |
64 | #if GNUTLS_VERSION_NUMBER >= 0x030104 |
65 | # define GNUTLS_CERT_VFY_STATUS_PRINT | |
66 | #endif | |
925ac8e4 JH |
67 | #if GNUTLS_VERSION_NUMBER >= 0x030109 |
68 | # define SUPPORT_CORK | |
69 | #endif | |
f20cfa4a JH |
70 | #if GNUTLS_VERSION_NUMBER >= 0x03010a |
71 | # define SUPPORT_GNUTLS_SESS_DESC | |
72 | #endif | |
4d2a62a3 JH |
73 | #if GNUTLS_VERSION_NUMBER >= 0x030300 |
74 | # define GNUTLS_AUTO_GLOBAL_INIT | |
9f707b89 | 75 | # define GNUTLS_AUTO_PKCS11_MANUAL |
4d2a62a3 | 76 | #endif |
97277c1f JH |
77 | #if (GNUTLS_VERSION_NUMBER >= 0x030404) \ |
78 | || (GNUTLS_VERSION_NUMBER >= 0x030311) && (GNUTLS_VERSION_NUMBER & 0xffff00 == 0x030300) | |
79 | # ifndef DISABLE_OCSP | |
80 | # define EXIM_HAVE_OCSP | |
81 | # endif | |
82 | #endif | |
f20cfa4a JH |
83 | #if GNUTLS_VERSION_NUMBER >= 0x030500 |
84 | # define SUPPORT_GNUTLS_KEYLOG | |
85 | #endif | |
47195144 JH |
86 | #if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP) |
87 | # define SUPPORT_SRV_OCSP_STACK | |
88 | #endif | |
49132a3b JH |
89 | #if GNUTLS_VERSION_NUMBER >= 0x030600 |
90 | # define GNUTLS_AUTO_DHPARAMS | |
91 | #endif | |
be427508 | 92 | #if GNUTLS_VERSION_NUMBER >= 0x030603 |
e326959e | 93 | # define EXIM_HAVE_TLS1_3 |
be427508 | 94 | # define SUPPORT_GNUTLS_EXT_RAW_PARSE |
e326959e | 95 | # define GNUTLS_OCSP_STATUS_REQUEST_GET2 |
be427508 | 96 | #endif |
c0635b6d JH |
97 | |
98 | #ifdef SUPPORT_DANE | |
99 | # if GNUTLS_VERSION_NUMBER >= 0x030000 | |
100 | # define DANESSL_USAGE_DANE_TA 2 | |
101 | # define DANESSL_USAGE_DANE_EE 3 | |
102 | # else | |
103 | # error GnuTLS version too early for DANE | |
104 | # endif | |
105 | # if GNUTLS_VERSION_NUMBER < 0x999999 | |
106 | # define GNUTLS_BROKEN_DANE_VALIDATION | |
107 | # endif | |
899b8bbc | 108 | #endif |
7e07527a | 109 | |
43e2db44 JH |
110 | #ifdef EXPERIMENTAL_TLS_RESUME |
111 | # if GNUTLS_VERSION_NUMBER < 0x030603 | |
112 | # error GNUTLS version too early for session-resumption | |
113 | # endif | |
114 | #endif | |
115 | ||
f2de3a33 | 116 | #ifndef DISABLE_OCSP |
2b4a568d JH |
117 | # include <gnutls/ocsp.h> |
118 | #endif | |
899b8bbc JH |
119 | #ifdef SUPPORT_DANE |
120 | # include <gnutls/dane.h> | |
121 | #endif | |
059ec3d9 | 122 | |
f1be21cf JH |
123 | #include "tls-cipher-stdname.c" |
124 | ||
125 | ||
b10c87b3 JH |
126 | #ifdef MACRO_PREDEF |
127 | void | |
128 | options_tls(void) | |
129 | { | |
130 | # ifdef EXPERIMENTAL_TLS_RESUME | |
131 | builtin_macro_create_var(US"_RESUME_DECODE", RESUME_DECODE_STRING ); | |
132 | # endif | |
e326959e JH |
133 | # ifdef EXIM_HAVE_TLS1_3 |
134 | builtin_macro_create(US"_HAVE_TLS1_3"); | |
135 | # endif | |
97277c1f JH |
136 | # ifdef EXIM_HAVE_OCSP |
137 | builtin_macro_create(US"_HAVE_TLS_OCSP"); | |
138 | # endif | |
139 | # ifdef SUPPORT_SRV_OCSP_STACK | |
140 | builtin_macro_create(US"_HAVE_TLS_OCSP_LIST"); | |
141 | # endif | |
b10c87b3 JH |
142 | } |
143 | #else | |
144 | ||
145 | ||
17c76198 | 146 | /* GnuTLS 2 vs 3 |
059ec3d9 | 147 | |
17c76198 PP |
148 | GnuTLS 3 only: |
149 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 150 | |
17c76198 PP |
151 | Changes: |
152 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
153 | */ | |
059ec3d9 | 154 | |
17c76198 | 155 | /* Local static variables for GnuTLS */ |
059ec3d9 | 156 | |
17c76198 | 157 | /* Values for verify_requirement */ |
059ec3d9 | 158 | |
e51c7be2 | 159 | enum peer_verify_requirement |
899b8bbc | 160 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED, VERIFY_DANE }; |
059ec3d9 | 161 | |
17c76198 PP |
162 | /* This holds most state for server or client; with this, we can set up an |
163 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
164 | over the TLS variables available for expansion. | |
059ec3d9 | 165 | |
17c76198 PP |
166 | Some of these correspond to variables in globals.c; those variables will |
167 | be set to point to content in one of these instances, as appropriate for | |
168 | the stage of the process lifetime. | |
059ec3d9 | 169 | |
b1a32a3c | 170 | Not handled here: global tlsp->tls_channelbinding. |
17c76198 | 171 | */ |
059ec3d9 | 172 | |
17c76198 | 173 | typedef struct exim_gnutls_state { |
9d1c15ef | 174 | gnutls_session_t session; |
17c76198 | 175 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 176 | gnutls_priority_t priority_cache; |
17c76198 | 177 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
178 | int fd_in; |
179 | int fd_out; | |
180 | BOOL peer_cert_verified; | |
899b8bbc | 181 | BOOL peer_dane_verified; |
9d1c15ef JH |
182 | BOOL trigger_sni_changes; |
183 | BOOL have_set_peerdn; | |
5fd28bb8 | 184 | const struct host_item *host; /* NULL if server */ |
afdb5e9c | 185 | gnutls_x509_crt_t peercert; |
9d1c15ef JH |
186 | uschar *peerdn; |
187 | uschar *ciphersuite; | |
188 | uschar *received_sni; | |
17c76198 PP |
189 | |
190 | const uschar *tls_certificate; | |
191 | const uschar *tls_privatekey; | |
192 | const uschar *tls_sni; /* client send only, not received */ | |
193 | const uschar *tls_verify_certificates; | |
194 | const uschar *tls_crl; | |
195 | const uschar *tls_require_ciphers; | |
e51c7be2 | 196 | |
17c76198 PP |
197 | uschar *exp_tls_certificate; |
198 | uschar *exp_tls_privatekey; | |
17c76198 PP |
199 | uschar *exp_tls_verify_certificates; |
200 | uschar *exp_tls_crl; | |
201 | uschar *exp_tls_require_ciphers; | |
55414b25 | 202 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 203 | #ifndef DISABLE_EVENT |
a7538db1 JH |
204 | uschar *event_action; |
205 | #endif | |
899b8bbc JH |
206 | #ifdef SUPPORT_DANE |
207 | char * const * dane_data; | |
208 | const int * dane_data_len; | |
209 | #endif | |
17c76198 | 210 | |
389ca47a | 211 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 212 | |
17c76198 PP |
213 | uschar *xfer_buffer; |
214 | int xfer_buffer_lwm; | |
215 | int xfer_buffer_hwm; | |
8b77d27a JH |
216 | BOOL xfer_eof; /*XXX never gets set! */ |
217 | BOOL xfer_error; | |
17c76198 PP |
218 | } exim_gnutls_state_st; |
219 | ||
220 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
b10c87b3 | 221 | /* all elements not explicitly intialised here get 0/NULL/FALSE */ |
f2ed27cf JH |
222 | .fd_in = -1, |
223 | .fd_out = -1, | |
17c76198 | 224 | }; |
83da1223 | 225 | |
17c76198 PP |
226 | /* Not only do we have our own APIs which don't pass around state, assuming |
227 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
228 | for callbacks, or as part of the session, so we have to keep a "this is the | |
229 | context we're currently dealing with" pointer and rely upon being | |
230 | single-threaded to keep from processing data on an inbound TLS connection while | |
231 | talking to another TLS connection for an outbound check. This does mean that | |
232 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
233 | second connection. |
234 | XXX But see gnutls_session_get_ptr() | |
235 | */ | |
059ec3d9 | 236 | |
74f1a423 | 237 | static exim_gnutls_state_st state_server; |
059ec3d9 | 238 | |
49132a3b | 239 | #ifndef GNUTLS_AUTO_DHPARAMS |
17c76198 PP |
240 | /* dh_params are initialised once within the lifetime of a process using TLS; |
241 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
242 | don't want to repeat this. */ | |
83da1223 | 243 | |
17c76198 | 244 | static gnutls_dh_params_t dh_server_params = NULL; |
49132a3b | 245 | #endif |
059ec3d9 | 246 | |
dea4b568 | 247 | static int ssl_session_timeout = 7200; /* Two hours */ |
059ec3d9 | 248 | |
fc243e94 | 249 | static const uschar * const exim_default_gnutls_priority = US"NORMAL"; |
83da1223 | 250 | |
17c76198 | 251 | /* Guard library core initialisation */ |
83da1223 | 252 | |
17c76198 | 253 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 254 | |
4fb7df6d | 255 | #ifndef DISABLE_OCSP |
9196d5bf | 256 | static BOOL gnutls_buggy_ocsp = FALSE; |
e5489333 | 257 | static BOOL exim_testharness_disable_ocsp_validity_check = FALSE; |
4fb7df6d | 258 | #endif |
9196d5bf | 259 | |
b10c87b3 JH |
260 | #ifdef EXPERIMENTAL_TLS_RESUME |
261 | static gnutls_datum_t server_sessticket_key; | |
262 | #endif | |
059ec3d9 | 263 | |
17c76198 PP |
264 | /* ------------------------------------------------------------------------ */ |
265 | /* macros */ | |
83da1223 | 266 | |
17c76198 | 267 | #define MAX_HOST_LEN 255 |
83da1223 | 268 | |
17c76198 PP |
269 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
270 | the library logging; a value less than 0 disables the calls to set up logging | |
dc6d1769 JH |
271 | callbacks. GNuTLS also looks for an environment variable - except not for |
272 | setuid binaries, making it useless - "GNUTLS_DEBUG_LEVEL". | |
273 | Allegedly the testscript line "GNUTLS_DEBUG_LEVEL=9 sudo exim ..." would work, | |
274 | but the env var must be added to /etc/sudoers too. */ | |
2c17bb02 | 275 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
b1a4f234 | 276 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 277 | #endif |
83da1223 | 278 | |
2c17bb02 | 279 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 280 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 281 | #endif |
83da1223 | 282 | |
af3498d6 PP |
283 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
284 | can ask for a bit-strength. Without that, we stick to the constant we had | |
285 | before, for now. */ | |
2c17bb02 | 286 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 287 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 288 | #endif |
af3498d6 | 289 | |
cf0c6164 JH |
290 | #define expand_check_tlsvar(Varname, errstr) \ |
291 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 292 | |
17c76198 | 293 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
294 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
295 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
296 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
297 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
298 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
299 | * isn't available sometimes, so this needs to become a conditional | |
300 | * compilation; the sanest way to deal with this being a problem on | |
301 | * older OSes is to block it in the Local/Makefile with this compiler | |
302 | * definition */ | |
e51c7be2 JH |
303 | # ifndef AVOID_GNUTLS_PKCS11 |
304 | # define HAVE_GNUTLS_PKCS11 | |
305 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 306 | #endif |
83da1223 | 307 | |
af3498d6 PP |
308 | |
309 | ||
310 | ||
311 | /* ------------------------------------------------------------------------ */ | |
312 | /* Callback declarations */ | |
313 | ||
314 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
315 | static void exim_gnutls_logger_cb(int level, const char *message); | |
316 | #endif | |
317 | ||
318 | static int exim_sni_handling_cb(gnutls_session_t session); | |
319 | ||
e5489333 JH |
320 | #ifdef EXPERIMENTAL_TLS_RESUME |
321 | static int | |
322 | tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
323 | unsigned incoming, const gnutls_datum_t * msg); | |
324 | #endif | |
af3498d6 PP |
325 | |
326 | ||
b10c87b3 JH |
327 | /* Daemon one-time initialisation */ |
328 | void | |
329 | tls_daemon_init(void) | |
330 | { | |
331 | #ifdef EXPERIMENTAL_TLS_RESUME | |
332 | /* We are dependent on the GnuTLS implementation of the Session Ticket | |
333 | encryption; both the strength and the key rotation period. We hope that | |
334 | the strength at least matches that of the ciphersuite (but GnuTLS does not | |
335 | document this). */ | |
336 | ||
337 | static BOOL once = FALSE; | |
338 | if (once) return; | |
339 | once = TRUE; | |
340 | gnutls_session_ticket_key_generate(&server_sessticket_key); /* >= 2.10.0 */ | |
341 | if (f.running_in_test_harness) ssl_session_timeout = 6; | |
342 | #endif | |
343 | } | |
344 | ||
17c76198 PP |
345 | /* ------------------------------------------------------------------------ */ |
346 | /* Static functions */ | |
059ec3d9 PH |
347 | |
348 | /************************************************* | |
349 | * Handle TLS error * | |
350 | *************************************************/ | |
351 | ||
352 | /* Called from lots of places when errors occur before actually starting to do | |
353 | the TLS handshake, that is, while the session is still in clear. Always returns | |
354 | DEFER for a server and FAIL for a client so that most calls can use "return | |
355 | tls_error(...)" to do this processing and then give an appropriate return. A | |
356 | single function is used for both server and client, because it is called from | |
357 | some shared functions. | |
358 | ||
359 | Argument: | |
360 | prefix text to include in the logged error | |
7199e1ee TF |
361 | msg additional error string (may be NULL) |
362 | usually obtained from gnutls_strerror() | |
17c76198 PP |
363 | host NULL if setting up a server; |
364 | the connected host if setting up a client | |
cf0c6164 | 365 | errstr pointer to returned error string |
059ec3d9 PH |
366 | |
367 | Returns: OK/DEFER/FAIL | |
368 | */ | |
369 | ||
370 | static int | |
48224640 | 371 | tls_error(const uschar *prefix, const uschar *msg, const host_item *host, |
cf0c6164 | 372 | uschar ** errstr) |
059ec3d9 | 373 | { |
cf0c6164 | 374 | if (errstr) |
48224640 | 375 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : US""); |
cf0c6164 | 376 | return host ? FAIL : DEFER; |
059ec3d9 PH |
377 | } |
378 | ||
379 | ||
452a164f JH |
380 | static int |
381 | tls_error_gnu(const uschar *prefix, int err, const host_item *host, | |
382 | uschar ** errstr) | |
383 | { | |
384 | return tls_error(prefix, US gnutls_strerror(err), host, errstr); | |
385 | } | |
386 | ||
387 | static int | |
388 | tls_error_sys(const uschar *prefix, int err, const host_item *host, | |
389 | uschar ** errstr) | |
390 | { | |
391 | return tls_error(prefix, US strerror(err), host, errstr); | |
392 | } | |
059ec3d9 | 393 | |
17c76198 | 394 | |
059ec3d9 | 395 | /************************************************* |
17c76198 | 396 | * Deal with logging errors during I/O * |
059ec3d9 PH |
397 | *************************************************/ |
398 | ||
17c76198 | 399 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 400 | |
17c76198 PP |
401 | Argument: |
402 | state the current GnuTLS exim state container | |
403 | rc the GnuTLS error code, or 0 if it's a local error | |
404 | when text identifying read or write | |
95f52235 | 405 | text local error text when rc is 0 |
059ec3d9 | 406 | |
17c76198 | 407 | Returns: nothing |
059ec3d9 PH |
408 | */ |
409 | ||
17c76198 PP |
410 | static void |
411 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 412 | { |
48224640 | 413 | const uschar * msg; |
cf0c6164 | 414 | uschar * errstr; |
059ec3d9 | 415 | |
17c76198 | 416 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
95f52235 | 417 | msg = string_sprintf("A TLS fatal alert has been received: %s", |
17c76198 PP |
418 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); |
419 | else | |
48224640 | 420 | msg = US gnutls_strerror(rc); |
059ec3d9 | 421 | |
cf0c6164 JH |
422 | (void) tls_error(when, msg, state->host, &errstr); |
423 | ||
424 | if (state->host) | |
425 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
426 | state->host->name, state->host->address, errstr); | |
427 | else | |
428 | { | |
429 | uschar * conn_info = smtp_get_connection_info(); | |
430 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
431 | /* I'd like to get separated H= here, but too hard for now */ | |
432 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
433 | } | |
17c76198 | 434 | } |
059ec3d9 | 435 | |
059ec3d9 | 436 | |
059ec3d9 | 437 | |
059ec3d9 | 438 | |
17c76198 PP |
439 | /************************************************* |
440 | * Set various Exim expansion vars * | |
441 | *************************************************/ | |
059ec3d9 | 442 | |
e51c7be2 JH |
443 | #define exim_gnutls_cert_err(Label) \ |
444 | do \ | |
445 | { \ | |
446 | if (rc != GNUTLS_E_SUCCESS) \ | |
447 | { \ | |
448 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
449 | (Label), gnutls_strerror(rc)); \ | |
450 | return rc; \ | |
451 | } \ | |
452 | } while (0) | |
9d1c15ef JH |
453 | |
454 | static int | |
27f19eb4 | 455 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
456 | { |
457 | int rc; | |
458 | ||
459 | rc = gnutls_x509_crt_init(crtp); | |
460 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
461 | ||
462 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
463 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
464 | ||
465 | return rc; | |
466 | } | |
467 | ||
468 | #undef exim_gnutls_cert_err | |
469 | ||
470 | ||
17c76198 PP |
471 | /* We set various Exim global variables from the state, once a session has |
472 | been established. With TLS callouts, may need to change this to stack | |
473 | variables, or just re-call it with the server state after client callout | |
474 | has finished. | |
059ec3d9 | 475 | |
9d1c15ef | 476 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
477 | |
478 | Sets: | |
479 | tls_active fd | |
480 | tls_bits strength indicator | |
481 | tls_certificate_verified bool indicator | |
b1a32a3c | 482 | tls_channelbinding for some SASL mechanisms |
da40b1ec | 483 | tls_ver a string |
17c76198 | 484 | tls_cipher a string |
9d1c15ef | 485 | tls_peercert pointer to library internal |
17c76198 PP |
486 | tls_peerdn a string |
487 | tls_sni a (UTF-8) string | |
9d1c15ef | 488 | tls_ourcert pointer to library internal |
17c76198 PP |
489 | |
490 | Argument: | |
491 | state the relevant exim_gnutls_state_st * | |
492 | */ | |
493 | ||
494 | static void | |
9d1c15ef | 495 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 496 | { |
17c76198 PP |
497 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
498 | int old_pool; | |
499 | int rc; | |
500 | gnutls_datum_t channel; | |
501 | #endif | |
9d1c15ef | 502 | tls_support * tlsp = state->tlsp; |
17c76198 | 503 | |
74f1a423 JH |
504 | tlsp->active.sock = state->fd_out; |
505 | tlsp->active.tls_ctx = state; | |
17c76198 | 506 | |
817d9f57 | 507 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 508 | |
9d1c15ef | 509 | tlsp->certificate_verified = state->peer_cert_verified; |
899b8bbc JH |
510 | #ifdef SUPPORT_DANE |
511 | tlsp->dane_verified = state->peer_dane_verified; | |
512 | #endif | |
059ec3d9 | 513 | |
b1a32a3c | 514 | /* note that tls_channelbinding is not saved to the spool file, since it's |
17c76198 PP |
515 | only available for use for authenticators while this TLS session is running. */ |
516 | ||
b1a32a3c | 517 | tlsp->channelbinding = NULL; |
17c76198 PP |
518 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
519 | channel.data = NULL; | |
520 | channel.size = 0; | |
1f20760b JH |
521 | if ((rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel))) |
522 | { DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); } | |
523 | else | |
524 | { | |
b1a32a3c JH |
525 | /* Declare the taintedness of the binding info. On server, untainted; on |
526 | client, tainted - being the Finish msg from the server. */ | |
527 | ||
17c76198 PP |
528 | old_pool = store_pool; |
529 | store_pool = POOL_PERM; | |
b1a32a3c JH |
530 | tlsp->channelbinding = b64encode_taint(CUS channel.data, (int)channel.size, |
531 | !!state->host); | |
17c76198 | 532 | store_pool = old_pool; |
b1a32a3c | 533 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage\n"); |
1f20760b | 534 | } |
17c76198 PP |
535 | #endif |
536 | ||
9d1c15ef JH |
537 | /* peercert is set in peer_status() */ |
538 | tlsp->peerdn = state->peerdn; | |
539 | tlsp->sni = state->received_sni; | |
540 | ||
541 | /* record our certificate */ | |
542 | { | |
27f19eb4 | 543 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
544 | gnutls_x509_crt_t crt; |
545 | ||
546 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
547 | } | |
059ec3d9 PH |
548 | } |
549 | ||
550 | ||
551 | ||
17c76198 | 552 | |
49132a3b | 553 | #ifndef GNUTLS_AUTO_DHPARAMS |
059ec3d9 | 554 | /************************************************* |
575643cd | 555 | * Setup up DH parameters * |
059ec3d9 PH |
556 | *************************************************/ |
557 | ||
575643cd | 558 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
559 | be re-generated every so often, depending on security policy. What we do is to |
560 | keep these parameters in a file in the spool directory. If the file does not | |
561 | exist, we generate them. This means that it is easy to cause a regeneration. | |
562 | ||
563 | The new file is written as a temporary file and renamed, so that an incomplete | |
564 | file is never present. If two processes both compute some new parameters, you | |
565 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
566 | prevent this. | |
567 | ||
059ec3d9 PH |
568 | Returns: OK/DEFER/FAIL |
569 | */ | |
570 | ||
571 | static int | |
cf0c6164 | 572 | init_server_dh(uschar ** errstr) |
059ec3d9 | 573 | { |
17c76198 PP |
574 | int fd, rc; |
575 | unsigned int dh_bits; | |
49132a3b | 576 | gnutls_datum_t m = {.data = NULL, .size = 0}; |
a799883d PP |
577 | uschar filename_buf[PATH_MAX]; |
578 | uschar *filename = NULL; | |
17c76198 | 579 | size_t sz; |
a799883d PP |
580 | uschar *exp_tls_dhparam; |
581 | BOOL use_file_in_spool = FALSE; | |
17c76198 | 582 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 583 | |
17c76198 | 584 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 585 | |
452a164f JH |
586 | if ((rc = gnutls_dh_params_init(&dh_server_params))) |
587 | return tls_error_gnu(US"gnutls_dh_params_init", rc, host, errstr); | |
059ec3d9 | 588 | |
cf0c6164 | 589 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
590 | return DEFER; |
591 | ||
592 | if (!exp_tls_dhparam) | |
593 | { | |
594 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
595 | m.data = US std_dh_prime_default(); | |
596 | m.size = Ustrlen(m.data); | |
597 | } | |
598 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
599 | use_file_in_spool = TRUE; | |
600 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
601 | { | |
602 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
603 | return OK; | |
604 | } | |
605 | else if (exp_tls_dhparam[0] != '/') | |
606 | { | |
f5d25c2b | 607 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
48224640 | 608 | return tls_error(US"No standard prime named", exp_tls_dhparam, NULL, errstr); |
a799883d PP |
609 | m.size = Ustrlen(m.data); |
610 | } | |
611 | else | |
a799883d | 612 | filename = exp_tls_dhparam; |
a799883d PP |
613 | |
614 | if (m.data) | |
615 | { | |
452a164f JH |
616 | if ((rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM))) |
617 | return tls_error_gnu(US"gnutls_dh_params_import_pkcs3", rc, host, errstr); | |
a799883d PP |
618 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); |
619 | return OK; | |
620 | } | |
621 | ||
af3498d6 PP |
622 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
623 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 | 624 | different filename and ensure we have sufficient bits. */ |
452a164f JH |
625 | |
626 | if (!(dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL))) | |
cf0c6164 | 627 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 628 | DEBUG(D_tls) |
b34fc30c | 629 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
630 | dh_bits); |
631 | #else | |
632 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
633 | DEBUG(D_tls) | |
634 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
635 | dh_bits); | |
636 | #endif | |
059ec3d9 | 637 | |
3375e053 PP |
638 | /* Some clients have hard-coded limits. */ |
639 | if (dh_bits > tls_dh_max_bits) | |
640 | { | |
641 | DEBUG(D_tls) | |
642 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
643 | tls_dh_max_bits); | |
644 | dh_bits = tls_dh_max_bits; | |
645 | } | |
646 | ||
a799883d PP |
647 | if (use_file_in_spool) |
648 | { | |
649 | if (!string_format(filename_buf, sizeof(filename_buf), | |
650 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 651 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
652 | filename = filename_buf; |
653 | } | |
059ec3d9 | 654 | |
b5aea5e1 | 655 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 656 | parameters. */ |
059ec3d9 | 657 | |
f5d25c2b | 658 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 659 | { |
b5aea5e1 | 660 | struct stat statbuf; |
17c76198 PP |
661 | FILE *fp; |
662 | int saved_errno; | |
663 | ||
664 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
665 | { | |
666 | saved_errno = errno; | |
667 | (void)close(fd); | |
452a164f | 668 | return tls_error_sys(US"TLS cache stat failed", saved_errno, NULL, errstr); |
17c76198 PP |
669 | } |
670 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
671 | { |
672 | (void)close(fd); | |
cf0c6164 | 673 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 674 | } |
40c90bca | 675 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
676 | { |
677 | saved_errno = errno; | |
678 | (void)close(fd); | |
452a164f JH |
679 | return tls_error_sys(US"fdopen(TLS cache stat fd) failed", |
680 | saved_errno, NULL, errstr); | |
b5aea5e1 | 681 | } |
059ec3d9 | 682 | |
b5aea5e1 | 683 | m.size = statbuf.st_size; |
f3ebb786 | 684 | if (!(m.data = store_malloc(m.size))) |
17c76198 PP |
685 | { |
686 | fclose(fp); | |
452a164f | 687 | return tls_error_sys(US"malloc failed", errno, NULL, errstr); |
17c76198 | 688 | } |
40c90bca | 689 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
690 | { |
691 | saved_errno = errno; | |
692 | fclose(fp); | |
f3ebb786 | 693 | store_free(m.data); |
452a164f | 694 | return tls_error_sys(US"fread failed", saved_errno, NULL, errstr); |
17c76198 PP |
695 | } |
696 | fclose(fp); | |
b5aea5e1 | 697 | |
17c76198 | 698 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
f3ebb786 | 699 | store_free(m.data); |
452a164f JH |
700 | if (rc) |
701 | return tls_error_gnu(US"gnutls_dh_params_import_pkcs3", rc, host, errstr); | |
17c76198 | 702 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); |
b5aea5e1 PH |
703 | } |
704 | ||
705 | /* If the file does not exist, fall through to compute new data and cache it. | |
706 | If there was any other opening error, it is serious. */ | |
707 | ||
182ad5cf PH |
708 | else if (errno == ENOENT) |
709 | { | |
17c76198 | 710 | rc = -1; |
182ad5cf | 711 | DEBUG(D_tls) |
17c76198 | 712 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
713 | } |
714 | else | |
17c76198 | 715 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 716 | NULL, NULL, errstr); |
b5aea5e1 PH |
717 | |
718 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
719 | is not useful. One particular case of this is when upgrading from an older | |
720 | release of Exim in which the data was stored in a different format. We don't | |
721 | try to be clever and support both formats; we just regenerate new data in this | |
722 | case. */ | |
723 | ||
17c76198 | 724 | if (rc < 0) |
b5aea5e1 | 725 | { |
17c76198 | 726 | uschar *temp_fn; |
201f5254 | 727 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 728 | |
17c76198 PP |
729 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
730 | return tls_error(US"Filename too long to generate replacement", | |
48224640 | 731 | filename, NULL, errstr); |
059ec3d9 | 732 | |
48224640 | 733 | temp_fn = string_copy(US"%s.XXXXXXX"); |
f5d25c2b | 734 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
452a164f | 735 | return tls_error_sys(US"Unable to open temp file", errno, NULL, errstr); |
b66fecb4 | 736 | (void)exim_chown(temp_fn, exim_uid, exim_gid); /* Probably not necessary */ |
059ec3d9 | 737 | |
49132a3b JH |
738 | /* GnuTLS overshoots! If we ask for 2236, we might get 2237 or more. But |
739 | there's no way to ask GnuTLS how many bits there really are. We can ask | |
740 | how many bits were used in a TLS session, but that's it! The prime itself | |
741 | is hidden behind too much abstraction. So we ask for less, and proceed on | |
742 | a wing and a prayer. First attempt, subtracted 3 for 2233 and got 2240. */ | |
743 | ||
cae6e576 | 744 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
745 | { |
746 | dh_bits_gen = dh_bits - 10; | |
747 | DEBUG(D_tls) | |
748 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
749 | dh_bits_gen); | |
750 | } | |
751 | ||
752 | DEBUG(D_tls) | |
753 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
754 | dh_bits_gen); | |
452a164f JH |
755 | if ((rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen))) |
756 | return tls_error_gnu(US"gnutls_dh_params_generate2", rc, host, errstr); | |
17c76198 PP |
757 | |
758 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
759 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
760 | sample apps handle this. */ | |
761 | ||
762 | sz = 0; | |
763 | m.data = NULL; | |
452a164f JH |
764 | if ( (rc = gnutls_dh_params_export_pkcs3(dh_server_params, |
765 | GNUTLS_X509_FMT_PEM, m.data, &sz)) | |
766 | && rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
767 | return tls_error_gnu(US"gnutls_dh_params_export_pkcs3(NULL) sizing", | |
768 | rc, host, errstr); | |
17c76198 | 769 | m.size = sz; |
f3ebb786 | 770 | if (!(m.data = store_malloc(m.size))) |
452a164f | 771 | return tls_error_sys(US"memory allocation failed", errno, NULL, errstr); |
40c90bca | 772 | |
1f00591e | 773 | /* this will return a size 1 less than the allocation size above */ |
452a164f JH |
774 | if ((rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
775 | m.data, &sz))) | |
17c76198 | 776 | { |
f3ebb786 | 777 | store_free(m.data); |
452a164f | 778 | return tls_error_gnu(US"gnutls_dh_params_export_pkcs3() real", rc, host, errstr); |
17c76198 | 779 | } |
1f00591e | 780 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 781 | |
f5d25c2b | 782 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 | 783 | { |
f3ebb786 | 784 | store_free(m.data); |
452a164f JH |
785 | return tls_error_sys(US"TLS cache write D-H params failed", |
786 | errno, NULL, errstr); | |
17c76198 | 787 | } |
f3ebb786 | 788 | store_free(m.data); |
f5d25c2b | 789 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
452a164f JH |
790 | return tls_error_sys(US"TLS cache write D-H params final newline failed", |
791 | errno, NULL, errstr); | |
17c76198 | 792 | |
f5d25c2b | 793 | if ((rc = close(fd))) |
452a164f | 794 | return tls_error_sys(US"TLS cache write close() failed", errno, NULL, errstr); |
059ec3d9 | 795 | |
17c76198 | 796 | if (Urename(temp_fn, filename) < 0) |
452a164f JH |
797 | return tls_error_sys(string_sprintf("failed to rename \"%s\" as \"%s\"", |
798 | temp_fn, filename), errno, NULL, errstr); | |
059ec3d9 | 799 | |
17c76198 | 800 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
801 | } |
802 | ||
17c76198 | 803 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
804 | return OK; |
805 | } | |
49132a3b | 806 | #endif |
059ec3d9 PH |
807 | |
808 | ||
809 | ||
810 | ||
23bb6982 JH |
811 | /* Create and install a selfsigned certificate, for use in server mode */ |
812 | ||
813 | static int | |
cf0c6164 | 814 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
815 | { |
816 | gnutls_x509_crt_t cert = NULL; | |
817 | time_t now; | |
818 | gnutls_x509_privkey_t pkey = NULL; | |
819 | const uschar * where; | |
820 | int rc; | |
821 | ||
822 | where = US"initialising pkey"; | |
823 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
824 | ||
825 | where = US"initialising cert"; | |
826 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
827 | ||
828 | where = US"generating pkey"; | |
829 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 830 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
4312da48 JH |
831 | # ifndef GNUTLS_SEC_PARAM_MEDIUM |
832 | # define GNUTLS_SEC_PARAM_MEDIUM GNUTLS_SEC_PARAM_HIGH | |
833 | # endif | |
6aac3239 | 834 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_MEDIUM), |
76075bb5 | 835 | #else |
6aac3239 | 836 | 2048, |
76075bb5 JH |
837 | #endif |
838 | 0))) | |
23bb6982 JH |
839 | goto err; |
840 | ||
841 | where = US"configuring cert"; | |
1613fd68 | 842 | now = 1; |
23bb6982 JH |
843 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) |
844 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
845 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
846 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
847 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
848 | ||
849 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
850 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
851 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
852 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
853 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
854 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
855 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
856 | ) | |
857 | goto err; | |
858 | ||
859 | where = US"signing cert"; | |
860 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
861 | ||
862 | where = US"installing selfsign cert"; | |
863 | /* Since: 2.4.0 */ | |
864 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
865 | goto err; | |
866 | ||
867 | rc = OK; | |
868 | ||
869 | out: | |
870 | if (cert) gnutls_x509_crt_deinit(cert); | |
871 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
872 | return rc; | |
873 | ||
874 | err: | |
452a164f | 875 | rc = tls_error_gnu(where, rc, NULL, errstr); |
23bb6982 JH |
876 | goto out; |
877 | } | |
878 | ||
879 | ||
880 | ||
881 | ||
47195144 JH |
882 | /* Add certificate and key, from files. |
883 | ||
884 | Return: | |
885 | Zero or negative: good. Negate value for certificate index if < 0. | |
886 | Greater than zero: FAIL or DEFER code. | |
887 | */ | |
888 | ||
ba86e143 JH |
889 | static int |
890 | tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, | |
891 | uschar * certfile, uschar * keyfile, uschar ** errstr) | |
892 | { | |
893 | int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, | |
894 | CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); | |
47195144 | 895 | if (rc < 0) |
452a164f | 896 | return tls_error_gnu( |
47195144 | 897 | string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile), |
452a164f | 898 | rc, host, errstr); |
47195144 | 899 | return -rc; |
ba86e143 JH |
900 | } |
901 | ||
902 | ||
d896cef5 JH |
903 | #if !defined(DISABLE_OCSP) && !defined(SUPPORT_GNUTLS_EXT_RAW_PARSE) |
904 | /* Load an OCSP proof from file for sending by the server. Called | |
905 | on getting a status-request handshake message, for earlier versions | |
906 | of GnuTLS. */ | |
907 | ||
908 | static int | |
909 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
910 | gnutls_datum_t * ocsp_response) | |
911 | { | |
912 | int ret; | |
913 | DEBUG(D_tls) debug_printf("OCSP stapling callback: %s\n", US ptr); | |
914 | ||
915 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) | |
916 | { | |
917 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
918 | CS ptr); | |
919 | tls_in.ocsp = OCSP_NOT_RESP; | |
920 | return GNUTLS_E_NO_CERTIFICATE_STATUS; | |
921 | } | |
922 | ||
923 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; | |
924 | return 0; | |
925 | } | |
926 | #endif | |
927 | ||
928 | ||
be427508 | 929 | #ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE |
e5489333 JH |
930 | /* Make a note that we saw a status-request */ |
931 | static int | |
932 | tls_server_clienthello_ext(void * ctx, unsigned tls_id, | |
933 | const unsigned char *data, unsigned size) | |
934 | { | |
935 | /* https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml */ | |
936 | if (tls_id == 5) /* status_request */ | |
937 | { | |
e326959e | 938 | DEBUG(D_tls) debug_printf("Seen status_request extension from client\n"); |
e5489333 JH |
939 | tls_in.ocsp = OCSP_NOT_RESP; |
940 | } | |
941 | return 0; | |
942 | } | |
943 | ||
944 | /* Callback for client-hello, on server, if we think we might serve stapled-OCSP */ | |
945 | static int | |
946 | tls_server_clienthello_cb(gnutls_session_t session, unsigned int htype, | |
947 | unsigned when, unsigned int incoming, const gnutls_datum_t * msg) | |
948 | { | |
949 | /* Call fn for each extension seen. 3.6.3 onwards */ | |
950 | return gnutls_ext_raw_parse(NULL, tls_server_clienthello_ext, msg, | |
951 | GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO); | |
952 | } | |
e326959e JH |
953 | |
954 | ||
955 | /* Make a note that we saw a status-response */ | |
956 | static int | |
957 | tls_server_servercerts_ext(void * ctx, unsigned tls_id, | |
958 | const unsigned char *data, unsigned size) | |
959 | { | |
960 | /* debug_printf("%s %u\n", __FUNCTION__, tls_id); */ | |
961 | /* https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml */ | |
962 | if (FALSE && tls_id == 5) /* status_request */ | |
963 | { | |
964 | DEBUG(D_tls) debug_printf("Seen status_request extension\n"); | |
965 | tls_in.ocsp = exim_testharness_disable_ocsp_validity_check | |
966 | ? OCSP_VFY_NOT_TRIED : OCSP_VFIED; /* We know that GnuTLS verifies responses */ | |
967 | } | |
968 | return 0; | |
969 | } | |
970 | ||
971 | /* Callback for certificates packet, on server, if we think we might serve stapled-OCSP */ | |
972 | static int | |
973 | tls_server_servercerts_cb(gnutls_session_t session, unsigned int htype, | |
974 | unsigned when, unsigned int incoming, const gnutls_datum_t * msg) | |
975 | { | |
976 | /* Call fn for each extension seen. 3.6.3 onwards */ | |
977 | #ifdef notdef | |
978 | /*XXX crashes */ | |
979 | return gnutls_ext_raw_parse(NULL, tls_server_servercerts_ext, msg, 0); | |
980 | #endif | |
981 | } | |
be427508 | 982 | #endif |
e5489333 | 983 | |
e326959e JH |
984 | /*XXX in tls1.3 the cert-status travel as an extension next to the cert, in the |
985 | "Handshake Protocol: Certificate" record. | |
986 | So we need to spot the Certificate handshake message, parse it and spot any status_request extension(s) | |
987 | ||
988 | This is different to tls1.2 - where it is a separate record (wireshake term) / handshake message (gnutls term). | |
989 | */ | |
990 | ||
727a5d25 | 991 | #if defined(EXPERIMENTAL_TLS_RESUME) || defined(SUPPORT_GNUTLS_EXT_RAW_PARSE) |
e5489333 JH |
992 | /* Callback for certificate-status, on server. We sent stapled OCSP. */ |
993 | static int | |
994 | tls_server_certstatus_cb(gnutls_session_t session, unsigned int htype, | |
995 | unsigned when, unsigned int incoming, const gnutls_datum_t * msg) | |
996 | { | |
e326959e | 997 | DEBUG(D_tls) debug_printf("Sending certificate-status\n"); /*XXX we get this for tls1.2 but not for 1.3 */ |
e5489333 JH |
998 | #ifdef SUPPORT_SRV_OCSP_STACK |
999 | tls_in.ocsp = exim_testharness_disable_ocsp_validity_check | |
1000 | ? OCSP_VFY_NOT_TRIED : OCSP_VFIED; /* We know that GnuTLS verifies responses */ | |
1001 | #else | |
1002 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; | |
1003 | #endif | |
1004 | return 0; | |
1005 | } | |
1006 | ||
1007 | /* Callback for handshake messages, on server */ | |
1008 | static int | |
1009 | tls_server_hook_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
1010 | unsigned incoming, const gnutls_datum_t * msg) | |
1011 | { | |
e326959e | 1012 | /* debug_printf("%s: htype %u\n", __FUNCTION__, htype); */ |
e5489333 JH |
1013 | switch (htype) |
1014 | { | |
727a5d25 | 1015 | # ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE |
e5489333 JH |
1016 | case GNUTLS_HANDSHAKE_CLIENT_HELLO: |
1017 | return tls_server_clienthello_cb(sess, htype, when, incoming, msg); | |
e326959e JH |
1018 | case GNUTLS_HANDSHAKE_CERTIFICATE_PKT: |
1019 | return tls_server_servercerts_cb(sess, htype, when, incoming, msg); | |
727a5d25 | 1020 | # endif |
e5489333 JH |
1021 | case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS: |
1022 | return tls_server_certstatus_cb(sess, htype, when, incoming, msg); | |
727a5d25 | 1023 | # ifdef EXPERIMENTAL_TLS_RESUME |
e5489333 JH |
1024 | case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET: |
1025 | return tls_server_ticket_cb(sess, htype, when, incoming, msg); | |
727a5d25 | 1026 | # endif |
e5489333 JH |
1027 | default: |
1028 | return 0; | |
1029 | } | |
1030 | } | |
727a5d25 | 1031 | #endif |
e5489333 JH |
1032 | |
1033 | ||
727a5d25 | 1034 | #if !defined(DISABLE_OCSP) && defined(SUPPORT_GNUTLS_EXT_RAW_PARSE) |
e5489333 JH |
1035 | static void |
1036 | tls_server_testharness_ocsp_fiddle(void) | |
1037 | { | |
1038 | extern char ** environ; | |
1039 | if (environ) for (uschar ** p = USS environ; *p; p++) | |
1040 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
1041 | { | |
1042 | DEBUG(D_tls) debug_printf("Permitting known bad OCSP response\n"); | |
1043 | exim_testharness_disable_ocsp_validity_check = TRUE; | |
1044 | } | |
1045 | } | |
727a5d25 | 1046 | #endif |
e5489333 | 1047 | |
059ec3d9 | 1048 | /************************************************* |
17c76198 | 1049 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
1050 | *************************************************/ |
1051 | ||
17c76198 PP |
1052 | /* Called from both server and client code, via tls_init(), and also from |
1053 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
1054 | ||
1055 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
1056 | ||
1057 | The callback should not call us unless state->trigger_sni_changes is true, | |
1058 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
1059 | |
1060 | Arguments: | |
17c76198 | 1061 | state exim_gnutls_state_st * |
cf0c6164 | 1062 | errstr error string pointer |
059ec3d9 PH |
1063 | |
1064 | Returns: OK/DEFER/FAIL | |
1065 | */ | |
1066 | ||
1067 | static int | |
ba86e143 | 1068 | tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 1069 | { |
1365611d | 1070 | struct stat statbuf; |
059ec3d9 | 1071 | int rc; |
17c76198 PP |
1072 | const host_item *host = state->host; /* macro should be reconsidered? */ |
1073 | uschar *saved_tls_certificate = NULL; | |
1074 | uschar *saved_tls_privatekey = NULL; | |
1075 | uschar *saved_tls_verify_certificates = NULL; | |
1076 | uschar *saved_tls_crl = NULL; | |
1077 | int cert_count; | |
1078 | ||
1079 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 1080 | if (!host) /* server */ |
17c76198 PP |
1081 | if (!state->received_sni) |
1082 | { | |
ba86e143 JH |
1083 | if ( state->tls_certificate |
1084 | && ( Ustrstr(state->tls_certificate, US"tls_sni") | |
1085 | || Ustrstr(state->tls_certificate, US"tls_in_sni") | |
1086 | || Ustrstr(state->tls_certificate, US"tls_out_sni") | |
1087 | ) ) | |
17c76198 PP |
1088 | { |
1089 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
1090 | state->trigger_sni_changes = TRUE; | |
1091 | } | |
1092 | } | |
1093 | else | |
1094 | { | |
1365611d | 1095 | /* useful for debugging */ |
17c76198 PP |
1096 | saved_tls_certificate = state->exp_tls_certificate; |
1097 | saved_tls_privatekey = state->exp_tls_privatekey; | |
1098 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
1099 | saved_tls_crl = state->exp_tls_crl; | |
1100 | } | |
059ec3d9 | 1101 | |
452a164f JH |
1102 | if ((rc = gnutls_certificate_allocate_credentials(&state->x509_cred))) |
1103 | return tls_error_gnu(US"gnutls_certificate_allocate_credentials", | |
1104 | rc, host, errstr); | |
47195144 JH |
1105 | |
1106 | #ifdef SUPPORT_SRV_OCSP_STACK | |
1107 | gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2); | |
e326959e JH |
1108 | |
1109 | # if !defined(DISABLE_OCSP) && defined(SUPPORT_GNUTLS_EXT_RAW_PARSE) | |
1110 | if (!host && tls_ocsp_file) | |
1111 | { | |
1112 | if (f.running_in_test_harness) | |
1113 | tls_server_testharness_ocsp_fiddle(); | |
1114 | ||
1115 | if (exim_testharness_disable_ocsp_validity_check) | |
1116 | gnutls_certificate_set_flags(state->x509_cred, | |
1117 | GNUTLS_CERTIFICATE_API_V2 | GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK); | |
1118 | } | |
1119 | # endif | |
47195144 | 1120 | #endif |
1365611d | 1121 | |
17c76198 PP |
1122 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
1123 | state members, assuming consistent naming; and expand_check() returns | |
1124 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 1125 | |
17c76198 PP |
1126 | /* check if we at least have a certificate, before doing expensive |
1127 | D-H generation. */ | |
059ec3d9 | 1128 | |
cf0c6164 | 1129 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 1130 | return DEFER; |
059ec3d9 | 1131 | |
17c76198 | 1132 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 1133 | |
23bb6982 JH |
1134 | if ( !state->exp_tls_certificate |
1135 | || !*state->exp_tls_certificate | |
1136 | ) | |
2b4a568d | 1137 | if (!host) |
cf0c6164 | 1138 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
1139 | else |
1140 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 1141 | |
cf0c6164 | 1142 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
1143 | return DEFER; |
1144 | ||
17c76198 PP |
1145 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
1146 | ||
e326959e | 1147 | if (!state->tls_privatekey || !*state->tls_privatekey) |
059ec3d9 | 1148 | { |
17c76198 PP |
1149 | state->tls_privatekey = state->tls_certificate; |
1150 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 1151 | } |
c91535f3 | 1152 | |
059ec3d9 | 1153 | |
17c76198 | 1154 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
1155 | { |
1156 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
1157 | state->exp_tls_certificate, state->exp_tls_privatekey); |
1158 | ||
1159 | if (state->received_sni) | |
23bb6982 JH |
1160 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
1161 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
1162 | ) | |
17c76198 | 1163 | { |
b34fc30c | 1164 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
1165 | } |
1166 | else | |
1167 | { | |
b34fc30c | 1168 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 1169 | } |
059ec3d9 | 1170 | |
ba86e143 JH |
1171 | if (!host) /* server */ |
1172 | { | |
1173 | const uschar * clist = state->exp_tls_certificate; | |
1174 | const uschar * klist = state->exp_tls_privatekey; | |
47195144 JH |
1175 | const uschar * olist; |
1176 | int csep = 0, ksep = 0, osep = 0, cnt = 0; | |
1177 | uschar * cfile, * kfile, * ofile; | |
47195144 | 1178 | #ifndef DISABLE_OCSP |
e326959e JH |
1179 | # ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE |
1180 | gnutls_x509_crt_fmt_t ocsp_fmt = GNUTLS_X509_FMT_DER; | |
1181 | # endif | |
1182 | ||
47195144 JH |
1183 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr)) |
1184 | return DEFER; | |
1185 | olist = ofile; | |
1186 | #endif | |
ba86e143 JH |
1187 | |
1188 | while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) | |
47195144 | 1189 | |
ba86e143 JH |
1190 | if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) |
1191 | return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); | |
47195144 | 1192 | else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr))) |
ba86e143 JH |
1193 | return rc; |
1194 | else | |
47195144 JH |
1195 | { |
1196 | int gnutls_cert_index = -rc; | |
e326959e JH |
1197 | DEBUG(D_tls) debug_printf("TLS: cert/key %d %s registered\n", |
1198 | gnutls_cert_index, cfile); | |
47195144 JH |
1199 | |
1200 | #ifndef DISABLE_OCSP | |
1201 | if (tls_ocsp_file) | |
e5489333 | 1202 | { |
e326959e | 1203 | /* Set the OCSP stapling server info */ |
47195144 JH |
1204 | if (gnutls_buggy_ocsp) |
1205 | { | |
1206 | DEBUG(D_tls) | |
1207 | debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
1208 | } | |
1209 | else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) | |
1210 | { | |
e326959e JH |
1211 | DEBUG(D_tls) debug_printf("OCSP response file %d = %s\n", |
1212 | gnutls_cert_index, ofile); | |
be427508 | 1213 | # ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE |
e326959e | 1214 | if (Ustrncmp(ofile, US"PEM ", 4) == 0) |
47195144 | 1215 | { |
e326959e JH |
1216 | ocsp_fmt = GNUTLS_X509_FMT_PEM; |
1217 | ofile += 4; | |
1218 | } | |
1219 | else if (Ustrncmp(ofile, US"DER ", 4) == 0) | |
1220 | { | |
1221 | ocsp_fmt = GNUTLS_X509_FMT_DER; | |
1222 | ofile += 4; | |
1223 | } | |
e5489333 | 1224 | |
e326959e JH |
1225 | if ((rc = gnutls_certificate_set_ocsp_status_request_file2( |
1226 | state->x509_cred, CCS ofile, gnutls_cert_index, | |
1227 | ocsp_fmt)) < 0) | |
1228 | return tls_error_gnu( | |
1229 | US"gnutls_certificate_set_ocsp_status_request_file2", | |
1230 | rc, host, errstr); | |
1231 | DEBUG(D_tls) | |
1232 | debug_printf(" %d response%s loaded\n", rc, rc>1 ? "s":""); | |
e5489333 | 1233 | |
e326959e JH |
1234 | /* Arrange callbacks for OCSP request observability */ |
1235 | ||
1236 | gnutls_handshake_set_hook_function(state->session, | |
1237 | GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb); | |
1238 | ||
1239 | # else | |
1240 | # if defined(SUPPORT_SRV_OCSP_STACK) | |
be427508 JH |
1241 | if ((rc = gnutls_certificate_set_ocsp_status_request_function2( |
1242 | state->x509_cred, gnutls_cert_index, | |
1243 | server_ocsp_stapling_cb, ofile))) | |
1244 | return tls_error_gnu( | |
1245 | US"gnutls_certificate_set_ocsp_status_request_function2", | |
1246 | rc, host, errstr); | |
1247 | else | |
e326959e | 1248 | # endif |
e5489333 JH |
1249 | { |
1250 | if (cnt++ > 0) | |
1251 | { | |
1252 | DEBUG(D_tls) | |
1253 | debug_printf("oops; multiple OCSP files not supported\n"); | |
1254 | break; | |
1255 | } | |
d896cef5 JH |
1256 | gnutls_certificate_set_ocsp_status_request_function( |
1257 | state->x509_cred, server_ocsp_stapling_cb, ofile); | |
e5489333 | 1258 | } |
e326959e | 1259 | # endif /* SUPPORT_GNUTLS_EXT_RAW_PARSE */ |
47195144 JH |
1260 | } |
1261 | else | |
1262 | DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); | |
e5489333 | 1263 | } |
fd71e7b8 | 1264 | #endif /* DISABLE_OCSP */ |
47195144 | 1265 | } |
ba86e143 | 1266 | } |
e5489333 | 1267 | else /* client */ |
ba86e143 | 1268 | { |
47195144 | 1269 | if (0 < (rc = tls_add_certfile(state, host, |
ba86e143 JH |
1270 | state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) |
1271 | return rc; | |
1272 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
1273 | } | |
1274 | ||
b34fc30c | 1275 | } /* tls_certificate */ |
059ec3d9 | 1276 | |
2b4a568d | 1277 | |
059ec3d9 PH |
1278 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
1279 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
1280 | error message is provided. However, if we just refrain from setting anything up | |
1281 | in that case, certificate verification fails, which seems to be the correct | |
1282 | behaviour. */ | |
1283 | ||
610ff438 | 1284 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 1285 | { |
cf0c6164 | 1286 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 1287 | return DEFER; |
610ff438 JH |
1288 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
1289 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1290 | state->exp_tls_verify_certificates = NULL; | |
1291 | #endif | |
17c76198 | 1292 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 1293 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 1294 | return DEFER; |
059ec3d9 | 1295 | |
1365611d PP |
1296 | if (!(state->exp_tls_verify_certificates && |
1297 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
1298 | { |
1299 | DEBUG(D_tls) | |
1365611d PP |
1300 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
1301 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 1302 | return OK; |
b34fc30c | 1303 | } |
1365611d | 1304 | } |
83e2f8a2 PP |
1305 | else |
1306 | { | |
1307 | DEBUG(D_tls) | |
1308 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
1309 | return OK; | |
1310 | } | |
17c76198 | 1311 | |
cb1d7830 JH |
1312 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
1313 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1314 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
1315 | else | |
1316 | #endif | |
1365611d | 1317 | { |
cb1d7830 JH |
1318 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
1319 | { | |
d896cef5 | 1320 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat '%s' " |
cb1d7830 JH |
1321 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, |
1322 | strerror(errno)); | |
1323 | return DEFER; | |
1324 | } | |
17c76198 | 1325 | |
a7fec7a7 | 1326 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1327 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1328 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1329 | other weirdness. The thing we really want to check is that it's not a | |
1330 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1331 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1332 | if (S_ISDIR(statbuf.st_mode)) |
1333 | { | |
1334 | DEBUG(D_tls) | |
1335 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1336 | state->exp_tls_verify_certificates); | |
1337 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1338 | "tls_verify_certificates \"%s\" is a directory", | |
1339 | state->exp_tls_verify_certificates); | |
1340 | return DEFER; | |
1341 | } | |
a7fec7a7 | 1342 | #endif |
059ec3d9 | 1343 | |
cb1d7830 JH |
1344 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1345 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1346 | |
cb1d7830 JH |
1347 | if (statbuf.st_size == 0) |
1348 | { | |
1349 | DEBUG(D_tls) | |
1350 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1351 | return OK; | |
1352 | } | |
059ec3d9 | 1353 | |
cb1d7830 | 1354 | cert_count = |
a7fec7a7 JH |
1355 | |
1356 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1357 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1358 | ? | |
1359 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1360 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1361 | : | |
a7fec7a7 | 1362 | #endif |
cb1d7830 JH |
1363 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1364 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
12d95aa6 JH |
1365 | |
1366 | #ifdef SUPPORT_CA_DIR | |
1367 | /* Mimic the behaviour with OpenSSL of not advertising a usable-cert list | |
1368 | when using the directory-of-certs config model. */ | |
1369 | ||
1370 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1371 | gnutls_certificate_send_x509_rdn_sequence(state->session, 1); | |
1372 | #endif | |
cb1d7830 | 1373 | } |
a7fec7a7 | 1374 | |
1365611d | 1375 | if (cert_count < 0) |
452a164f JH |
1376 | return tls_error_gnu(US"setting certificate trust", cert_count, host, errstr); |
1377 | DEBUG(D_tls) | |
1378 | debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1379 | |
5c8cda3a PP |
1380 | if (state->tls_crl && *state->tls_crl && |
1381 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1382 | { |
5c8cda3a | 1383 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
452a164f JH |
1384 | if ((cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, |
1385 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM)) < 0) | |
1386 | return tls_error_gnu(US"gnutls_certificate_set_x509_crl_file", | |
1387 | cert_count, host, errstr); | |
1388 | ||
5c8cda3a | 1389 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1390 | } |
059ec3d9 | 1391 | |
059ec3d9 PH |
1392 | return OK; |
1393 | } | |
1394 | ||
1395 | ||
1396 | ||
1397 | ||
1365611d PP |
1398 | /************************************************* |
1399 | * Set X.509 state variables * | |
1400 | *************************************************/ | |
1401 | ||
1402 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1403 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1404 | structure. Which means various other non-re-expanded pieces of state | |
1405 | need to be re-set in the new struct, so the setting logic is pulled | |
1406 | out to this. | |
1407 | ||
1408 | Arguments: | |
1409 | state exim_gnutls_state_st * | |
cf0c6164 | 1410 | errstr error string pointer |
1365611d PP |
1411 | |
1412 | Returns: OK/DEFER/FAIL | |
1413 | */ | |
1414 | ||
1415 | static int | |
cf0c6164 | 1416 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1417 | { |
1418 | int rc; | |
1419 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1420 | ||
49132a3b | 1421 | #ifndef GNUTLS_AUTO_DHPARAMS |
1365611d PP |
1422 | /* Create D-H parameters, or read them from the cache file. This function does |
1423 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1424 | client-side params. */ | |
1425 | ||
1426 | if (!state->host) | |
1427 | { | |
1428 | if (!dh_server_params) | |
452a164f | 1429 | if ((rc = init_server_dh(errstr)) != OK) return rc; |
49132a3b JH |
1430 | |
1431 | /* Unnecessary & discouraged with 3.6.0 or later */ | |
1365611d PP |
1432 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); |
1433 | } | |
49132a3b | 1434 | #endif |
1365611d PP |
1435 | |
1436 | /* Link the credentials to the session. */ | |
1437 | ||
452a164f JH |
1438 | if ((rc = gnutls_credentials_set(state->session, |
1439 | GNUTLS_CRD_CERTIFICATE, state->x509_cred))) | |
1440 | return tls_error_gnu(US"gnutls_credentials_set", rc, host, errstr); | |
1365611d PP |
1441 | |
1442 | return OK; | |
1443 | } | |
1444 | ||
059ec3d9 | 1445 | /************************************************* |
17c76198 | 1446 | * Initialize for GnuTLS * |
059ec3d9 PH |
1447 | *************************************************/ |
1448 | ||
9196d5bf | 1449 | |
4fb7df6d JH |
1450 | #ifndef DISABLE_OCSP |
1451 | ||
9196d5bf JH |
1452 | static BOOL |
1453 | tls_is_buggy_ocsp(void) | |
1454 | { | |
1455 | const uschar * s; | |
1456 | uschar maj, mid, mic; | |
1457 | ||
1458 | s = CUS gnutls_check_version(NULL); | |
1459 | maj = atoi(CCS s); | |
1460 | if (maj == 3) | |
1461 | { | |
1462 | while (*s && *s != '.') s++; | |
1463 | mid = atoi(CCS ++s); | |
1464 | if (mid <= 2) | |
1465 | return TRUE; | |
1466 | else if (mid >= 5) | |
1467 | return FALSE; | |
1468 | else | |
1469 | { | |
1470 | while (*s && *s != '.') s++; | |
1471 | mic = atoi(CCS ++s); | |
1472 | return mic <= (mid == 3 ? 16 : 3); | |
1473 | } | |
1474 | } | |
1475 | return FALSE; | |
1476 | } | |
1477 | ||
4fb7df6d | 1478 | #endif |
9196d5bf JH |
1479 | |
1480 | ||
17c76198 PP |
1481 | /* Called from both server and client code. In the case of a server, errors |
1482 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1483 | |
1484 | Arguments: | |
17c76198 PP |
1485 | host connected host, if client; NULL if server |
1486 | certificate certificate file | |
1487 | privatekey private key file | |
1488 | sni TLS SNI to send, sometimes when client; else NULL | |
1489 | cas CA certs file | |
1490 | crl CRL file | |
1491 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1492 | caller_state returned state-info structure |
cf0c6164 | 1493 | errstr error string pointer |
059ec3d9 | 1494 | |
17c76198 | 1495 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1496 | */ |
1497 | ||
17c76198 PP |
1498 | static int |
1499 | tls_init( | |
1500 | const host_item *host, | |
1501 | const uschar *certificate, | |
1502 | const uschar *privatekey, | |
1503 | const uschar *sni, | |
1504 | const uschar *cas, | |
1505 | const uschar *crl, | |
1506 | const uschar *require_ciphers, | |
cf0c6164 | 1507 | exim_gnutls_state_st **caller_state, |
74f1a423 | 1508 | tls_support * tlsp, |
cf0c6164 | 1509 | uschar ** errstr) |
059ec3d9 | 1510 | { |
00c0dd4e | 1511 | exim_gnutls_state_st * state; |
17c76198 PP |
1512 | int rc; |
1513 | size_t sz; | |
00c0dd4e JH |
1514 | const char * errpos; |
1515 | const uschar * p; | |
17c76198 PP |
1516 | |
1517 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1518 | { |
17c76198 PP |
1519 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1520 | ||
9f707b89 | 1521 | #if defined(HAVE_GNUTLS_PKCS11) && !defined(GNUTLS_AUTO_PKCS11_MANUAL) |
a5f239e4 PP |
1522 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, |
1523 | which loads modules from a config file, which sounds good and may be wanted | |
1524 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1525 | environment variables are used and so breaks for users calling mailq. | |
1526 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1527 | if (!gnutls_allow_auto_pkcs11) |
452a164f JH |
1528 | if ((rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL))) |
1529 | return tls_error_gnu(US"gnutls_pkcs11_init", rc, host, errstr); | |
a5f239e4 PP |
1530 | #endif |
1531 | ||
4d2a62a3 | 1532 | #ifndef GNUTLS_AUTO_GLOBAL_INIT |
452a164f JH |
1533 | if ((rc = gnutls_global_init())) |
1534 | return tls_error_gnu(US"gnutls_global_init", rc, host, errstr); | |
4d2a62a3 | 1535 | #endif |
17c76198 PP |
1536 | |
1537 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1538 | DEBUG(D_tls) | |
059ec3d9 | 1539 | { |
17c76198 | 1540 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
aded2255 | 1541 | /* arbitrarily chosen level; bump up to 9 for more */ |
17c76198 | 1542 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); |
059ec3d9 | 1543 | } |
17c76198 PP |
1544 | #endif |
1545 | ||
4fb7df6d JH |
1546 | #ifndef DISABLE_OCSP |
1547 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1548 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1549 | #endif |
9196d5bf | 1550 | |
17c76198 | 1551 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1552 | } |
059ec3d9 | 1553 | |
17c76198 PP |
1554 | if (host) |
1555 | { | |
74f1a423 JH |
1556 | /* For client-side sessions we allocate a context. This lets us run |
1557 | several in parallel. */ | |
1558 | int old_pool = store_pool; | |
1559 | store_pool = POOL_PERM; | |
f3ebb786 | 1560 | state = store_get(sizeof(exim_gnutls_state_st), FALSE); |
74f1a423 JH |
1561 | store_pool = old_pool; |
1562 | ||
17c76198 | 1563 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
74f1a423 | 1564 | state->tlsp = tlsp; |
17c76198 PP |
1565 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1566 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1567 | } | |
1568 | else | |
1569 | { | |
1570 | state = &state_server; | |
1571 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
74f1a423 | 1572 | state->tlsp = tlsp; |
17c76198 PP |
1573 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1574 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1575 | } | |
452a164f JH |
1576 | if (rc) |
1577 | return tls_error_gnu(US"gnutls_init", rc, host, errstr); | |
059ec3d9 | 1578 | |
17c76198 | 1579 | state->host = host; |
059ec3d9 | 1580 | |
17c76198 PP |
1581 | state->tls_certificate = certificate; |
1582 | state->tls_privatekey = privatekey; | |
5779e6aa | 1583 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1584 | state->tls_sni = sni; |
1585 | state->tls_verify_certificates = cas; | |
1586 | state->tls_crl = crl; | |
059ec3d9 | 1587 | |
17c76198 PP |
1588 | /* This handles the variables that might get re-expanded after TLS SNI; |
1589 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1590 | |
17c76198 PP |
1591 | DEBUG(D_tls) |
1592 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1593 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1594 | |
1365611d PP |
1595 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1596 | requires a new structure afterwards. */ | |
83da1223 | 1597 | |
cf0c6164 | 1598 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1599 | |
17c76198 PP |
1600 | /* set SNI in client, only */ |
1601 | if (host) | |
1602 | { | |
cf0c6164 | 1603 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1604 | return DEFER; |
0df4ab80 | 1605 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1606 | { |
1607 | DEBUG(D_tls) | |
0df4ab80 JH |
1608 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1609 | sz = Ustrlen(state->tlsp->sni); | |
452a164f JH |
1610 | if ((rc = gnutls_server_name_set(state->session, |
1611 | GNUTLS_NAME_DNS, state->tlsp->sni, sz))) | |
1612 | return tls_error_gnu(US"gnutls_server_name_set", rc, host, errstr); | |
17c76198 PP |
1613 | } |
1614 | } | |
1615 | else if (state->tls_sni) | |
1616 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
ba86e143 | 1617 | "have an SNI set for a server [%s]\n", state->tls_sni); |
83da1223 | 1618 | |
17c76198 | 1619 | /* This is the priority string support, |
42bfef1e | 1620 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1621 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1622 | This was backwards incompatible, but means Exim no longer needs to track | |
1623 | all algorithms and provide string forms for them. */ | |
83da1223 | 1624 | |
fc243e94 | 1625 | p = NULL; |
17c76198 | 1626 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1627 | { |
cf0c6164 | 1628 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1629 | return DEFER; |
1630 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1631 | { |
17c76198 | 1632 | p = state->exp_tls_require_ciphers; |
fc243e94 | 1633 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", p); |
83da1223 PH |
1634 | } |
1635 | } | |
fc243e94 | 1636 | if (!p) |
17c76198 | 1637 | { |
fc243e94 | 1638 | p = exim_default_gnutls_priority; |
83e2f8a2 | 1639 | DEBUG(D_tls) |
fc243e94 | 1640 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", p); |
17c76198 | 1641 | } |
83da1223 | 1642 | |
452a164f JH |
1643 | if ((rc = gnutls_priority_init(&state->priority_cache, CCS p, &errpos))) |
1644 | return tls_error_gnu(string_sprintf( | |
1645 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1646 | p, errpos - CS p, errpos), | |
1647 | rc, host, errstr); | |
17c76198 | 1648 | |
452a164f JH |
1649 | if ((rc = gnutls_priority_set(state->session, state->priority_cache))) |
1650 | return tls_error_gnu(US"gnutls_priority_set", rc, host, errstr); | |
17c76198 | 1651 | |
b10c87b3 JH |
1652 | /* This also sets the server ticket expiration time to the same, and |
1653 | the STEK rotation time to 3x. */ | |
1654 | ||
17c76198 PP |
1655 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); |
1656 | ||
1657 | /* Reduce security in favour of increased compatibility, if the admin | |
1658 | decides to make that trade-off. */ | |
1659 | if (gnutls_compat_mode) | |
83da1223 | 1660 | { |
17c76198 PP |
1661 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1662 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1663 | gnutls_session_enable_compatibility_mode(state->session); | |
1664 | #else | |
1665 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1666 | #endif | |
83da1223 PH |
1667 | } |
1668 | ||
17c76198 | 1669 | *caller_state = state; |
17c76198 | 1670 | return OK; |
83da1223 PH |
1671 | } |
1672 | ||
1673 | ||
1674 | ||
059ec3d9 | 1675 | /************************************************* |
17c76198 | 1676 | * Extract peer information * |
059ec3d9 PH |
1677 | *************************************************/ |
1678 | ||
f1be21cf JH |
1679 | static const uschar * |
1680 | cipher_stdname_kcm(gnutls_kx_algorithm_t kx, gnutls_cipher_algorithm_t cipher, | |
1681 | gnutls_mac_algorithm_t mac) | |
1682 | { | |
1683 | uschar cs_id[2]; | |
1684 | gnutls_kx_algorithm_t kx_i; | |
1685 | gnutls_cipher_algorithm_t cipher_i; | |
1686 | gnutls_mac_algorithm_t mac_i; | |
1687 | ||
1688 | for (size_t i = 0; | |
1689 | gnutls_cipher_suite_info(i, cs_id, &kx_i, &cipher_i, &mac_i, NULL); | |
1690 | i++) | |
1691 | if (kx_i == kx && cipher_i == cipher && mac_i == mac) | |
1692 | return cipher_stdname(cs_id[0], cs_id[1]); | |
1693 | return NULL; | |
1694 | } | |
1695 | ||
1696 | ||
1697 | ||
17c76198 | 1698 | /* Called from both server and client code. |
4fe99a6c PP |
1699 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1700 | and we use that to detect double-calls. | |
059ec3d9 | 1701 | |
75fe387d PP |
1702 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1703 | for logging in the server side, but for the client side, we log after teardown | |
1704 | in src/deliver.c. While the session is up, we can twist about states and | |
1705 | repoint tls_* globals, but those variables used for logging or other variable | |
1706 | expansion that happens _after_ delivery need to have a longer life-time. | |
1707 | ||
1708 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1709 | doing this more than once per generation of a state context. We set them in | |
1710 | the state context, and repoint tls_* to them. After the state goes away, the | |
1711 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1712 | ||
1713 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1714 | don't apply. | |
1715 | ||
059ec3d9 | 1716 | Arguments: |
17c76198 | 1717 | state exim_gnutls_state_st * |
cf0c6164 | 1718 | errstr pointer to error string |
059ec3d9 | 1719 | |
17c76198 | 1720 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1721 | */ |
1722 | ||
17c76198 | 1723 | static int |
b10c87b3 | 1724 | peer_status(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 1725 | { |
b10c87b3 JH |
1726 | gnutls_session_t session = state->session; |
1727 | const gnutls_datum_t * cert_list; | |
75fe387d | 1728 | int old_pool, rc; |
17c76198 | 1729 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1730 | gnutls_protocol_t protocol; |
1731 | gnutls_cipher_algorithm_t cipher; | |
1732 | gnutls_kx_algorithm_t kx; | |
1733 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1734 | gnutls_certificate_type_t ct; |
1735 | gnutls_x509_crt_t crt; | |
b10c87b3 | 1736 | uschar * dn_buf; |
17c76198 | 1737 | size_t sz; |
059ec3d9 | 1738 | |
4fe99a6c | 1739 | if (state->have_set_peerdn) |
17c76198 | 1740 | return OK; |
4fe99a6c | 1741 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1742 | |
4fe99a6c | 1743 | state->peerdn = NULL; |
059ec3d9 | 1744 | |
4fe99a6c | 1745 | /* tls_cipher */ |
b10c87b3 JH |
1746 | cipher = gnutls_cipher_get(session); |
1747 | protocol = gnutls_protocol_get_version(session); | |
1748 | mac = gnutls_mac_get(session); | |
b9c6f63c JH |
1749 | kx = |
1750 | #ifdef GNUTLS_TLS1_3 | |
1751 | protocol >= GNUTLS_TLS1_3 ? 0 : | |
1752 | #endif | |
b10c87b3 | 1753 | gnutls_kx_get(session); |
4fe99a6c | 1754 | |
75fe387d | 1755 | old_pool = store_pool; |
f1be21cf | 1756 | { |
b10c87b3 | 1757 | tls_support * tlsp = state->tlsp; |
f1be21cf | 1758 | store_pool = POOL_PERM; |
d9acfc1c JH |
1759 | |
1760 | #ifdef SUPPORT_GNUTLS_SESS_DESC | |
1761 | { | |
1762 | gstring * g = NULL; | |
b10c87b3 | 1763 | uschar * s = US gnutls_session_get_desc(session), c; |
d9acfc1c JH |
1764 | |
1765 | /* Nikos M suggests we use this by preference. It returns like: | |
1766 | (TLS1.3)-(ECDHE-SECP256R1)-(RSA-PSS-RSAE-SHA256)-(AES-256-GCM) | |
1767 | ||
1768 | For partial back-compat, put a colon after the TLS version, replace the | |
1769 | )-( grouping with __, replace in-group - with _ and append the :keysize. */ | |
1770 | ||
1771 | /* debug_printf("peer_status: gnutls_session_get_desc %s\n", s); */ | |
1772 | ||
1773 | for (s++; (c = *s) && c != ')'; s++) g = string_catn(g, s, 1); | |
da40b1ec JH |
1774 | |
1775 | tlsp->ver = string_copyn(g->s, g->ptr); | |
1776 | for (uschar * p = US tlsp->ver; *p; p++) | |
1777 | if (*p == '-') { *p = '\0'; break; } /* TLS1.0-PKIX -> TLS1.0 */ | |
1778 | ||
d9acfc1c JH |
1779 | g = string_catn(g, US":", 1); |
1780 | if (*s) s++; /* now on _ between groups */ | |
1781 | while ((c = *s)) | |
1782 | { | |
da40b1ec JH |
1783 | for (*++s && ++s; (c = *s) && c != ')'; s++) |
1784 | g = string_catn(g, c == '-' ? US"_" : s, 1); | |
d9acfc1c JH |
1785 | /* now on ) closing group */ |
1786 | if ((c = *s) && *++s == '-') g = string_catn(g, US"__", 2); | |
1787 | /* now on _ between groups */ | |
1788 | } | |
1789 | g = string_catn(g, US":", 1); | |
1790 | g = string_cat(g, string_sprintf("%d", (int) gnutls_cipher_get_key_size(cipher) * 8)); | |
1791 | state->ciphersuite = string_from_gstring(g); | |
1792 | } | |
1793 | #else | |
f1be21cf JH |
1794 | state->ciphersuite = string_sprintf("%s:%s:%d", |
1795 | gnutls_protocol_get_name(protocol), | |
1796 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1797 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1798 | ||
1799 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1800 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1801 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
1802 | ||
1803 | for (uschar * p = state->ciphersuite; *p; p++) if (isspace(*p)) *p = '-'; | |
da40b1ec JH |
1804 | tlsp->ver = string_copyn(state->ciphersuite, |
1805 | Ustrchr(state->ciphersuite, ':') - state->ciphersuite); | |
d9acfc1c JH |
1806 | #endif |
1807 | ||
1808 | /* debug_printf("peer_status: ciphersuite %s\n", state->ciphersuite); */ | |
1809 | ||
b10c87b3 JH |
1810 | tlsp->cipher = state->ciphersuite; |
1811 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; | |
f1be21cf | 1812 | |
b10c87b3 | 1813 | tlsp->cipher_stdname = cipher_stdname_kcm(kx, cipher, mac); |
f1be21cf | 1814 | } |
75fe387d | 1815 | store_pool = old_pool; |
4fe99a6c PP |
1816 | |
1817 | /* tls_peerdn */ | |
b10c87b3 | 1818 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); |
83da1223 | 1819 | |
f1be21cf | 1820 | if (!cert_list || cert_list_size == 0) |
17c76198 | 1821 | { |
17c76198 PP |
1822 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1823 | cert_list, cert_list_size); | |
e51c7be2 | 1824 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1825 | return tls_error(US"certificate verification failed", |
48224640 | 1826 | US"no certificate received from peer", state->host, errstr); |
17c76198 PP |
1827 | return OK; |
1828 | } | |
059ec3d9 | 1829 | |
b10c87b3 | 1830 | if ((ct = gnutls_certificate_type_get(session)) != GNUTLS_CRT_X509) |
059ec3d9 | 1831 | { |
95f52235 | 1832 | const uschar * ctn = US gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1833 | DEBUG(D_tls) |
1834 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1835 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1836 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1837 | ctn, state->host, errstr); |
17c76198 | 1838 | return OK; |
83da1223 | 1839 | } |
059ec3d9 | 1840 | |
e51c7be2 JH |
1841 | #define exim_gnutls_peer_err(Label) \ |
1842 | do { \ | |
1843 | if (rc != GNUTLS_E_SUCCESS) \ | |
1844 | { \ | |
1845 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1846 | (Label), gnutls_strerror(rc)); \ | |
1847 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
452a164f | 1848 | return tls_error_gnu((Label), rc, state->host, errstr); \ |
e51c7be2 JH |
1849 | return OK; \ |
1850 | } \ | |
1851 | } while (0) | |
17c76198 | 1852 | |
9d1c15ef JH |
1853 | rc = import_cert(&cert_list[0], &crt); |
1854 | exim_gnutls_peer_err(US"cert 0"); | |
1855 | ||
1856 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1857 | |
17c76198 PP |
1858 | sz = 0; |
1859 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1860 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1861 | { |
17c76198 PP |
1862 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1863 | return FAIL; /* should not happen */ | |
059ec3d9 | 1864 | } |
f3ebb786 | 1865 | dn_buf = store_get_perm(sz, TRUE); /* tainted */ |
17c76198 PP |
1866 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); |
1867 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1868 | |
17c76198 PP |
1869 | state->peerdn = dn_buf; |
1870 | ||
1871 | return OK; | |
1872 | #undef exim_gnutls_peer_err | |
1873 | } | |
059ec3d9 | 1874 | |
059ec3d9 | 1875 | |
059ec3d9 | 1876 | |
059ec3d9 | 1877 | |
17c76198 PP |
1878 | /************************************************* |
1879 | * Verify peer certificate * | |
1880 | *************************************************/ | |
059ec3d9 | 1881 | |
17c76198 PP |
1882 | /* Called from both server and client code. |
1883 | *Should* be using a callback registered with | |
1884 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1885 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1886 | |
17c76198 | 1887 | Arguments: |
899b8bbc JH |
1888 | state exim_gnutls_state_st * |
1889 | errstr where to put an error message | |
059ec3d9 | 1890 | |
17c76198 PP |
1891 | Returns: |
1892 | FALSE if the session should be rejected | |
1893 | TRUE if the cert is okay or we just don't care | |
1894 | */ | |
059ec3d9 | 1895 | |
17c76198 | 1896 | static BOOL |
28646fa9 | 1897 | verify_certificate(exim_gnutls_state_st * state, uschar ** errstr) |
17c76198 PP |
1898 | { |
1899 | int rc; | |
899b8bbc JH |
1900 | uint verify; |
1901 | ||
8008accd | 1902 | DEBUG(D_tls) debug_printf("TLS: checking peer certificate\n"); |
cf0c6164 | 1903 | *errstr = NULL; |
b10c87b3 | 1904 | rc = peer_status(state, errstr); |
17c76198 | 1905 | |
b10c87b3 JH |
1906 | if (state->verify_requirement == VERIFY_NONE) |
1907 | return TRUE; | |
1908 | ||
1909 | if (rc != OK || !state->peerdn) | |
e6060e2c | 1910 | { |
17c76198 | 1911 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1912 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1913 | } |
1914 | else | |
899b8bbc JH |
1915 | |
1916 | { | |
1917 | #ifdef SUPPORT_DANE | |
1918 | if (state->verify_requirement == VERIFY_DANE && state->host) | |
1919 | { | |
1920 | /* Using dane_verify_session_crt() would be easy, as it does it all for us | |
1921 | including talking to a DNS resolver. But we want to do that bit ourselves | |
1922 | as the testsuite intercepts and fakes its own DNS environment. */ | |
1923 | ||
1924 | dane_state_t s; | |
1925 | dane_query_t r; | |
899b8bbc | 1926 | uint lsize; |
94c13285 JH |
1927 | const gnutls_datum_t * certlist = |
1928 | gnutls_certificate_get_peers(state->session, &lsize); | |
1929 | int usage = tls_out.tlsa_usage; | |
1930 | ||
1931 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION | |
1932 | /* Split the TLSA records into two sets, TA and EE selectors. Run the | |
1933 | dane-verification separately so that we know which selector verified; | |
570cb1bd | 1934 | then we know whether to do name-verification (needed for TA but not EE). */ |
94c13285 JH |
1935 | |
1936 | if (usage == ((1<<DANESSL_USAGE_DANE_TA) | (1<<DANESSL_USAGE_DANE_EE))) | |
bd5b3f3c | 1937 | { /* a mixed-usage bundle */ |
94c13285 JH |
1938 | int i, j, nrec; |
1939 | const char ** dd; | |
1940 | int * ddl; | |
1941 | ||
3d2e82c5 | 1942 | for (nrec = 0; state->dane_data_len[nrec]; ) nrec++; |
94c13285 JH |
1943 | nrec++; |
1944 | ||
f3ebb786 JH |
1945 | dd = store_get(nrec * sizeof(uschar *), FALSE); |
1946 | ddl = store_get(nrec * sizeof(int), FALSE); | |
94c13285 JH |
1947 | nrec--; |
1948 | ||
1949 | if ((rc = dane_state_init(&s, 0))) | |
1950 | goto tlsa_prob; | |
1951 | ||
1952 | for (usage = DANESSL_USAGE_DANE_EE; | |
1953 | usage >= DANESSL_USAGE_DANE_TA; usage--) | |
1954 | { /* take records with this usage */ | |
1955 | for (j = i = 0; i < nrec; i++) | |
1956 | if (state->dane_data[i][0] == usage) | |
1957 | { | |
1958 | dd[j] = state->dane_data[i]; | |
1959 | ddl[j++] = state->dane_data_len[i]; | |
1960 | } | |
1961 | if (j) | |
1962 | { | |
1963 | dd[j] = NULL; | |
1964 | ddl[j] = 0; | |
1965 | ||
1966 | if ((rc = dane_raw_tlsa(s, &r, (char * const *)dd, ddl, 1, 0))) | |
1967 | goto tlsa_prob; | |
1968 | ||
1969 | if ((rc = dane_verify_crt_raw(s, certlist, lsize, | |
1970 | gnutls_certificate_type_get(state->session), | |
1971 | r, 0, | |
1972 | usage == DANESSL_USAGE_DANE_EE | |
1973 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1974 | &verify))) | |
1975 | { | |
1976 | DEBUG(D_tls) | |
1977 | debug_printf("TLSA record problem: %s\n", dane_strerror(rc)); | |
1978 | } | |
1979 | else if (verify == 0) /* verification passed */ | |
1980 | { | |
1981 | usage = 1 << usage; | |
1982 | break; | |
1983 | } | |
1984 | } | |
1985 | } | |
899b8bbc | 1986 | |
94c13285 JH |
1987 | if (rc) goto tlsa_prob; |
1988 | } | |
1989 | else | |
1990 | # endif | |
899b8bbc | 1991 | { |
94c13285 JH |
1992 | if ( (rc = dane_state_init(&s, 0)) |
1993 | || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len, | |
1994 | 1, 0)) | |
1995 | || (rc = dane_verify_crt_raw(s, certlist, lsize, | |
1996 | gnutls_certificate_type_get(state->session), | |
5ec37a55 | 1997 | r, 0, |
94c13285 JH |
1998 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1999 | usage == (1 << DANESSL_USAGE_DANE_EE) | |
2000 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
2001 | # else | |
2002 | 0, | |
2003 | # endif | |
2004 | &verify)) | |
2005 | ) | |
2006 | goto tlsa_prob; | |
899b8bbc | 2007 | } |
94c13285 JH |
2008 | |
2009 | if (verify != 0) /* verification failed */ | |
899b8bbc JH |
2010 | { |
2011 | gnutls_datum_t str; | |
2012 | (void) dane_verification_status_print(verify, &str, 0); | |
2013 | *errstr = US str.data; /* don't bother to free */ | |
2014 | goto badcert; | |
2015 | } | |
28646fa9 | 2016 | |
94c13285 JH |
2017 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
2018 | /* If a TA-mode TLSA record was used for verification we must additionally | |
570cb1bd | 2019 | verify the cert name (but not the CA chain). For EE-mode, skip it. */ |
28646fa9 | 2020 | |
94c13285 JH |
2021 | if (usage & (1 << DANESSL_USAGE_DANE_EE)) |
2022 | # endif | |
28646fa9 | 2023 | { |
570cb1bd | 2024 | state->peer_dane_verified = state->peer_cert_verified = TRUE; |
28646fa9 JH |
2025 | goto goodcert; |
2026 | } | |
570cb1bd JH |
2027 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
2028 | /* Assume that the name on the A-record is the one that should be matching | |
2029 | the cert. An alternate view is that the domain part of the email address | |
2030 | is also permissible. */ | |
2031 | ||
2032 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, | |
2033 | CS state->host->name)) | |
2034 | { | |
2035 | state->peer_dane_verified = state->peer_cert_verified = TRUE; | |
2036 | goto goodcert; | |
2037 | } | |
2038 | # endif | |
899b8bbc | 2039 | } |
570cb1bd | 2040 | #endif /*SUPPORT_DANE*/ |
899b8bbc | 2041 | |
17c76198 | 2042 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
899b8bbc | 2043 | } |
e6060e2c | 2044 | |
899b8bbc | 2045 | /* Handle the result of verification. INVALID is set if any others are. */ |
059ec3d9 | 2046 | |
28646fa9 | 2047 | if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) |
17c76198 PP |
2048 | { |
2049 | state->peer_cert_verified = FALSE; | |
cf0c6164 | 2050 | if (!*errstr) |
184384c3 JH |
2051 | { |
2052 | #ifdef GNUTLS_CERT_VFY_STATUS_PRINT | |
2053 | DEBUG(D_tls) | |
2054 | { | |
2055 | gnutls_datum_t txt; | |
2056 | ||
2057 | if (gnutls_certificate_verification_status_print(verify, | |
2058 | gnutls_certificate_type_get(state->session), &txt, 0) | |
2059 | == GNUTLS_E_SUCCESS) | |
2060 | { | |
2061 | debug_printf("%s\n", txt.data); | |
2062 | gnutls_free(txt.data); | |
2063 | } | |
2064 | } | |
2065 | #endif | |
cf0c6164 JH |
2066 | *errstr = verify & GNUTLS_CERT_REVOKED |
2067 | ? US"certificate revoked" : US"certificate invalid"; | |
184384c3 | 2068 | } |
059ec3d9 | 2069 | |
17c76198 | 2070 | DEBUG(D_tls) |
e51c7be2 | 2071 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 2072 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 2073 | |
e51c7be2 | 2074 | if (state->verify_requirement >= VERIFY_REQUIRED) |
899b8bbc | 2075 | goto badcert; |
17c76198 | 2076 | DEBUG(D_tls) |
4789da3a | 2077 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 2078 | } |
e51c7be2 | 2079 | |
17c76198 PP |
2080 | else |
2081 | { | |
5fd28bb8 JH |
2082 | /* Client side, check the server's certificate name versus the name on the |
2083 | A-record for the connection we made. What to do for server side - what name | |
2084 | to use for client? We document that there is no such checking for server | |
2085 | side. */ | |
2086 | ||
2087 | if ( state->exp_tls_verify_cert_hostnames | |
2088 | && !gnutls_x509_crt_check_hostname(state->tlsp->peercert, | |
2089 | CS state->exp_tls_verify_cert_hostnames) | |
2090 | ) | |
e51c7be2 | 2091 | { |
5fd28bb8 JH |
2092 | DEBUG(D_tls) |
2093 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
2094 | if (state->verify_requirement >= VERIFY_REQUIRED) | |
2095 | goto badcert; | |
2096 | return TRUE; | |
e51c7be2 | 2097 | } |
5fd28bb8 | 2098 | |
17c76198 | 2099 | state->peer_cert_verified = TRUE; |
e51c7be2 | 2100 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 2101 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 2102 | } |
059ec3d9 | 2103 | |
28646fa9 JH |
2104 | goodcert: |
2105 | state->tlsp->peerdn = state->peerdn; | |
2106 | return TRUE; | |
899b8bbc | 2107 | |
b83314e3 | 2108 | #ifdef SUPPORT_DANE |
94c13285 | 2109 | tlsa_prob: |
624f33df JH |
2110 | *errstr = string_sprintf("TLSA record problem: %s", |
2111 | rc == DANE_E_REQUESTED_DATA_NOT_AVAILABLE ? "none usable" : dane_strerror(rc)); | |
b83314e3 JH |
2112 | #endif |
2113 | ||
899b8bbc JH |
2114 | badcert: |
2115 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
2116 | return FALSE; | |
17c76198 | 2117 | } |
059ec3d9 | 2118 | |
17c76198 PP |
2119 | |
2120 | ||
2121 | ||
2122 | /* ------------------------------------------------------------------------ */ | |
2123 | /* Callbacks */ | |
2124 | ||
2125 | /* Logging function which can be registered with | |
2126 | * gnutls_global_set_log_function() | |
2127 | * gnutls_global_set_log_level() 0..9 | |
2128 | */ | |
af3498d6 | 2129 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 2130 | static void |
17c76198 | 2131 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 2132 | { |
8c79eebf PP |
2133 | size_t len = strlen(message); |
2134 | if (len < 1) | |
2135 | { | |
2136 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
2137 | return; | |
2138 | } | |
2139 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
2140 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 2141 | } |
af3498d6 | 2142 | #endif |
059ec3d9 | 2143 | |
059ec3d9 | 2144 | |
17c76198 PP |
2145 | /* Called after client hello, should handle SNI work. |
2146 | This will always set tls_sni (state->received_sni) if available, | |
2147 | and may trigger presenting different certificates, | |
2148 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 2149 | |
17c76198 PP |
2150 | Should be registered with |
2151 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 2152 | |
17c76198 PP |
2153 | "This callback must return 0 on success or a gnutls error code to terminate the |
2154 | handshake.". | |
059ec3d9 | 2155 | |
17c76198 PP |
2156 | For inability to get SNI information, we return 0. |
2157 | We only return non-zero if re-setup failed. | |
817d9f57 | 2158 | Only used for server-side TLS. |
17c76198 | 2159 | */ |
44bbabb5 | 2160 | |
17c76198 PP |
2161 | static int |
2162 | exim_sni_handling_cb(gnutls_session_t session) | |
2163 | { | |
2164 | char sni_name[MAX_HOST_LEN]; | |
2165 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 2166 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
2167 | unsigned int sni_type; |
2168 | int rc, old_pool; | |
cf0c6164 | 2169 | uschar * dummy_errstr; |
17c76198 PP |
2170 | |
2171 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
2172 | if (rc != GNUTLS_E_SUCCESS) |
2173 | { | |
8775d84f | 2174 | DEBUG(D_tls) |
b34fc30c PP |
2175 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) |
2176 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
2177 | else | |
2178 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
2179 | gnutls_strerror(rc), rc); | |
b34fc30c PP |
2180 | return 0; |
2181 | } | |
2182 | ||
17c76198 PP |
2183 | if (sni_type != GNUTLS_NAME_DNS) |
2184 | { | |
2185 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
2186 | return 0; | |
2187 | } | |
44bbabb5 | 2188 | |
17c76198 PP |
2189 | /* We now have a UTF-8 string in sni_name */ |
2190 | old_pool = store_pool; | |
2191 | store_pool = POOL_PERM; | |
89a80675 | 2192 | state->received_sni = string_copy_taint(US sni_name, TRUE); |
17c76198 PP |
2193 | store_pool = old_pool; |
2194 | ||
2195 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 2196 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
2197 | |
2198 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
2199 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
2200 | ||
2201 | if (!state->trigger_sni_changes) | |
2202 | return 0; | |
2203 | ||
cf0c6164 | 2204 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
2205 | { |
2206 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
2207 | been offered. The best we can do now is abort. */ | |
2208 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
2209 | } | |
2210 | ||
cf0c6164 | 2211 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
2212 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
2213 | ||
2214 | return 0; | |
059ec3d9 PH |
2215 | } |
2216 | ||
2217 | ||
2218 | ||
0cbf2b82 | 2219 | #ifndef DISABLE_EVENT |
a7538db1 JH |
2220 | /* |
2221 | We use this callback to get observability and detail-level control | |
723fe533 JH |
2222 | for an exim TLS connection (either direction), raising a tls:cert event |
2223 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
2224 | can deny verification. |
2225 | ||
2226 | Return 0 for the handshake to continue or non-zero to terminate. | |
2227 | */ | |
2228 | ||
2229 | static int | |
723fe533 | 2230 | verify_cb(gnutls_session_t session) |
a7538db1 | 2231 | { |
27f19eb4 | 2232 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
2233 | unsigned int cert_list_size = 0; |
2234 | gnutls_x509_crt_t crt; | |
2235 | int rc; | |
b30275b8 | 2236 | uschar * yield; |
a7538db1 JH |
2237 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
2238 | ||
bd5b3f3c | 2239 | if ((cert_list = gnutls_certificate_get_peers(session, &cert_list_size))) |
a7538db1 JH |
2240 | while (cert_list_size--) |
2241 | { | |
bd5b3f3c | 2242 | if ((rc = import_cert(&cert_list[cert_list_size], &crt)) != GNUTLS_E_SUCCESS) |
a7538db1 JH |
2243 | { |
2244 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
2245 | cert_list_size, gnutls_strerror(rc)); | |
2246 | break; | |
2247 | } | |
2248 | ||
2249 | state->tlsp->peercert = crt; | |
b30275b8 JH |
2250 | if ((yield = event_raise(state->event_action, |
2251 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
2252 | { |
2253 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
2254 | "SSL verify denied by event-action: depth=%d: %s", |
2255 | cert_list_size, yield); | |
a7538db1 JH |
2256 | return 1; /* reject */ |
2257 | } | |
2258 | state->tlsp->peercert = NULL; | |
2259 | } | |
2260 | ||
2261 | return 0; | |
2262 | } | |
2263 | ||
2264 | #endif | |
44662487 JH |
2265 | |
2266 | ||
f20cfa4a JH |
2267 | static gstring * |
2268 | ddump(gnutls_datum_t * d) | |
2269 | { | |
2270 | gstring * g = string_get((d->size+1) * 2); | |
2271 | uschar * s = d->data; | |
2272 | for (unsigned i = d->size; i > 0; i--, s++) | |
2273 | { | |
2274 | g = string_catn(g, US "0123456789abcdef" + (*s >> 4), 1); | |
2275 | g = string_catn(g, US "0123456789abcdef" + (*s & 0xf), 1); | |
2276 | } | |
2277 | return g; | |
2278 | } | |
17c76198 | 2279 | |
dc6d1769 JH |
2280 | static void |
2281 | post_handshake_debug(exim_gnutls_state_st * state) | |
2282 | { | |
dc6d1769 JH |
2283 | #ifdef SUPPORT_GNUTLS_SESS_DESC |
2284 | debug_printf("%s\n", gnutls_session_get_desc(state->session)); | |
2285 | #endif | |
e326959e | 2286 | |
86ede124 | 2287 | #ifdef SUPPORT_GNUTLS_KEYLOG |
e326959e | 2288 | # ifdef EXIM_HAVE_TLS1_3 |
dc6d1769 | 2289 | if (gnutls_protocol_get_version(state->session) < GNUTLS_TLS1_3) |
86ede124 | 2290 | # else |
a8af957d | 2291 | if (TRUE) |
86ede124 | 2292 | # endif |
dc6d1769 JH |
2293 | { |
2294 | gnutls_datum_t c, s; | |
2295 | gstring * gc, * gs; | |
86ede124 | 2296 | /* For TLS1.2 we only want the client random and the master secret */ |
dc6d1769 JH |
2297 | gnutls_session_get_random(state->session, &c, &s); |
2298 | gnutls_session_get_master_secret(state->session, &s); | |
2299 | gc = ddump(&c); | |
2300 | gs = ddump(&s); | |
2301 | debug_printf("CLIENT_RANDOM %.*s %.*s\n", (int)gc->ptr, gc->s, (int)gs->ptr, gs->s); | |
2302 | } | |
2303 | else | |
2304 | debug_printf("To get keying info for TLS1.3 is hard:\n" | |
2305 | " set environment variable SSLKEYLOGFILE to a filename writable by uid exim\n" | |
2306 | " add SSLKEYLOGFILE to keep_environment in the exim config\n" | |
2307 | " run exim as root\n" | |
e326959e | 2308 | " if using sudo, add SSLKEYLOGFILE to env_keep in /etc/sudoers\n" |
86ede124 JH |
2309 | " (works for TLS1.2 also, and saves cut-paste into file)" |
2310 | " Trying to use add_environment for this will not work\n"); | |
dc6d1769 JH |
2311 | #endif |
2312 | } | |
2313 | ||
b10c87b3 JH |
2314 | |
2315 | #ifdef EXPERIMENTAL_TLS_RESUME | |
2316 | static int | |
2317 | tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
2318 | unsigned incoming, const gnutls_datum_t * msg) | |
2319 | { | |
2320 | DEBUG(D_tls) debug_printf("newticket cb\n"); | |
2321 | tls_in.resumption |= RESUME_CLIENT_REQUESTED; | |
2322 | return 0; | |
2323 | } | |
2324 | ||
2325 | static void | |
2326 | tls_server_resume_prehandshake(exim_gnutls_state_st * state) | |
2327 | { | |
2328 | /* Should the server offer session resumption? */ | |
2329 | tls_in.resumption = RESUME_SUPPORTED; | |
2330 | if (verify_check_host(&tls_resumption_hosts) == OK) | |
2331 | { | |
2332 | int rc; | |
2333 | /* GnuTLS appears to not do ticket overlap, but does emit a fresh ticket when | |
2334 | an offered resumption is unacceptable. We lose one resumption per ticket | |
2335 | lifetime, and sessions cannot be indefinitely re-used. There seems to be no | |
2336 | way (3.6.7) of changing the default number of 2 TLS1.3 tickets issued, but at | |
2337 | least they go out in a single packet. */ | |
2338 | ||
2339 | if (!(rc = gnutls_session_ticket_enable_server(state->session, | |
2340 | &server_sessticket_key))) | |
2341 | tls_in.resumption |= RESUME_SERVER_TICKET; | |
2342 | else | |
2343 | DEBUG(D_tls) | |
2344 | debug_printf("enabling session tickets: %s\n", US gnutls_strerror(rc)); | |
2345 | ||
2346 | /* Try to tell if we see a ticket request */ | |
2347 | gnutls_handshake_set_hook_function(state->session, | |
e5489333 | 2348 | GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb); |
b10c87b3 JH |
2349 | } |
2350 | } | |
2351 | ||
2352 | static void | |
2353 | tls_server_resume_posthandshake(exim_gnutls_state_st * state) | |
2354 | { | |
2355 | if (gnutls_session_resumption_requested(state->session)) | |
2356 | { | |
2357 | /* This tells us the client sent a full ticket. We use a | |
2358 | callback on session-ticket request, elsewhere, to tell | |
2359 | if a client asked for a ticket. */ | |
2360 | ||
2361 | tls_in.resumption |= RESUME_CLIENT_SUGGESTED; | |
2362 | DEBUG(D_tls) debug_printf("client requested resumption\n"); | |
2363 | } | |
2364 | if (gnutls_session_is_resumed(state->session)) | |
2365 | { | |
2366 | tls_in.resumption |= RESUME_USED; | |
2367 | DEBUG(D_tls) debug_printf("Session resumed\n"); | |
2368 | } | |
2369 | } | |
2370 | #endif | |
17c76198 PP |
2371 | /* ------------------------------------------------------------------------ */ |
2372 | /* Exported functions */ | |
2373 | ||
2374 | ||
2375 | ||
2376 | ||
059ec3d9 PH |
2377 | /************************************************* |
2378 | * Start a TLS session in a server * | |
2379 | *************************************************/ | |
2380 | ||
2381 | /* This is called when Exim is running as a server, after having received | |
2382 | the STARTTLS command. It must respond to that command, and then negotiate | |
2383 | a TLS session. | |
2384 | ||
2385 | Arguments: | |
83da1223 | 2386 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 2387 | errstr pointer to error string |
059ec3d9 PH |
2388 | |
2389 | Returns: OK on success | |
2390 | DEFER for errors before the start of the negotiation | |
4c04137d | 2391 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
2392 | continue running. |
2393 | */ | |
2394 | ||
2395 | int | |
cf0c6164 | 2396 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
2397 | { |
2398 | int rc; | |
cf0c6164 | 2399 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
2400 | |
2401 | /* Check for previous activation */ | |
74f1a423 | 2402 | if (tls_in.active.sock >= 0) |
059ec3d9 | 2403 | { |
48224640 | 2404 | tls_error(US"STARTTLS received after TLS started", US "", NULL, errstr); |
925ac8e4 | 2405 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
2406 | return FAIL; |
2407 | } | |
2408 | ||
2409 | /* Initialize the library. If it fails, it will already have logged the error | |
2410 | and sent an SMTP response. */ | |
2411 | ||
17c76198 | 2412 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 2413 | |
d85cdeb5 JH |
2414 | { |
2415 | #ifdef MEASURE_TIMING | |
2416 | struct timeval t0; | |
2417 | gettimeofday(&t0, NULL); | |
2418 | #endif | |
2419 | ||
2420 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, | |
2421 | NULL, tls_verify_certificates, tls_crl, | |
2422 | require_ciphers, &state, &tls_in, errstr)) != OK) return rc; | |
2423 | ||
2424 | #ifdef MEASURE_TIMING | |
2425 | report_time_since(&t0, US"server tls_init (delta)"); | |
2426 | #endif | |
2427 | } | |
059ec3d9 | 2428 | |
b10c87b3 JH |
2429 | #ifdef EXPERIMENTAL_TLS_RESUME |
2430 | tls_server_resume_prehandshake(state); | |
2431 | #endif | |
2432 | ||
059ec3d9 PH |
2433 | /* If this is a host for which certificate verification is mandatory or |
2434 | optional, set up appropriately. */ | |
2435 | ||
059ec3d9 | 2436 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 2437 | { |
e51c7be2 JH |
2438 | DEBUG(D_tls) |
2439 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
2440 | state->verify_requirement = VERIFY_REQUIRED; |
2441 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
2442 | } | |
059ec3d9 | 2443 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 2444 | { |
e51c7be2 JH |
2445 | DEBUG(D_tls) |
2446 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
2447 | state->verify_requirement = VERIFY_OPTIONAL; |
2448 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
2449 | } | |
2450 | else | |
2451 | { | |
e51c7be2 JH |
2452 | DEBUG(D_tls) |
2453 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
2454 | state->verify_requirement = VERIFY_NONE; |
2455 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
2456 | } | |
059ec3d9 | 2457 | |
0cbf2b82 | 2458 | #ifndef DISABLE_EVENT |
723fe533 JH |
2459 | if (event_action) |
2460 | { | |
2461 | state->event_action = event_action; | |
2462 | gnutls_session_set_ptr(state->session, state); | |
2463 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
2464 | } | |
2465 | #endif | |
2466 | ||
17c76198 PP |
2467 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
2468 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 2469 | |
17c76198 PP |
2470 | gnutls_handshake_set_post_client_hello_function(state->session, |
2471 | exim_sni_handling_cb); | |
059ec3d9 PH |
2472 | |
2473 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2474 | on connection, where outputting anything now upsets the clients and tends to | |
2475 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2476 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2477 | mode, the fflush() happens when smtp_getc() is called. */ | |
2478 | ||
817d9f57 | 2479 | if (!state->tlsp->on_connect) |
059ec3d9 | 2480 | { |
925ac8e4 | 2481 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 2482 | fflush(smtp_out); |
059ec3d9 PH |
2483 | } |
2484 | ||
2485 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
8008accd JH |
2486 | that the GnuTLS library doesn't. |
2487 | From 3.1.0 there is gnutls_handshake_set_timeout() - but it requires you | |
2488 | to set (and clear down afterwards) up a pull-timeout callback function that does | |
2489 | a select, so we're no better off unless avoiding signals becomes an issue. */ | |
059ec3d9 | 2490 | |
17c76198 | 2491 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
2492 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
2493 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
2494 | state->fd_in = fileno(smtp_in); |
2495 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
2496 | |
2497 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2498 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
17c76198 | 2499 | do |
17c76198 | 2500 | rc = gnutls_handshake(state->session); |
157a7880 | 2501 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
c2a1bba0 | 2502 | ALARM_CLR(0); |
059ec3d9 | 2503 | |
17c76198 | 2504 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 2505 | { |
059ec3d9 PH |
2506 | /* It seems that, except in the case of a timeout, we have to close the |
2507 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
2508 | until the server times out. */ | |
2509 | ||
60d10ce7 | 2510 | if (sigalrm_seen) |
ad7fc6eb | 2511 | { |
48224640 | 2512 | tls_error(US"gnutls_handshake", US"timed out", NULL, errstr); |
ad7fc6eb JH |
2513 | gnutls_db_remove_session(state->session); |
2514 | } | |
60d10ce7 | 2515 | else |
059ec3d9 | 2516 | { |
452a164f | 2517 | tls_error_gnu(US"gnutls_handshake", rc, NULL, errstr); |
f5d25c2b | 2518 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 2519 | gnutls_deinit(state->session); |
ed62aae3 | 2520 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 2521 | millisleep(500); |
ad7fc6eb | 2522 | shutdown(state->fd_out, SHUT_WR); |
d7978c0f | 2523 | for (int i = 1024; fgetc(smtp_in) != EOF && i > 0; ) i--; /* drain skt */ |
f1e894f3 PH |
2524 | (void)fclose(smtp_out); |
2525 | (void)fclose(smtp_in); | |
60d10ce7 | 2526 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
2527 | } |
2528 | ||
2529 | return FAIL; | |
2530 | } | |
2531 | ||
17ba0f52 | 2532 | #ifdef GNUTLS_SFLAGS_EXT_MASTER_SECRET |
1c519e07 JH |
2533 | if (gnutls_session_get_flags(state->session) & GNUTLS_SFLAGS_EXT_MASTER_SECRET) |
2534 | tls_in.ext_master_secret = TRUE; | |
17ba0f52 | 2535 | #endif |
1c519e07 | 2536 | |
b10c87b3 JH |
2537 | #ifdef EXPERIMENTAL_TLS_RESUME |
2538 | tls_server_resume_posthandshake(state); | |
2539 | #endif | |
2540 | ||
dc6d1769 | 2541 | DEBUG(D_tls) post_handshake_debug(state); |
059ec3d9 | 2542 | |
17c76198 PP |
2543 | /* Verify after the fact */ |
2544 | ||
899b8bbc | 2545 | if (!verify_certificate(state, errstr)) |
059ec3d9 | 2546 | { |
9d1c15ef | 2547 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 2548 | { |
cf0c6164 | 2549 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 2550 | return FAIL; |
17c76198 | 2551 | } |
9d1c15ef JH |
2552 | DEBUG(D_tls) |
2553 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 2554 | *errstr); |
059ec3d9 PH |
2555 | } |
2556 | ||
17c76198 PP |
2557 | /* Sets various Exim expansion variables; always safe within server */ |
2558 | ||
9d1c15ef | 2559 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
2560 | |
2561 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2562 | and initialize appropriately. */ | |
2563 | ||
17c76198 | 2564 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
2565 | |
2566 | receive_getc = tls_getc; | |
0d81dabc | 2567 | receive_getbuf = tls_getbuf; |
584e96c6 | 2568 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2569 | receive_ungetc = tls_ungetc; |
2570 | receive_feof = tls_feof; | |
2571 | receive_ferror = tls_ferror; | |
58eb016e | 2572 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2573 | |
059ec3d9 PH |
2574 | return OK; |
2575 | } | |
2576 | ||
2577 | ||
2578 | ||
2579 | ||
aa2a70ba JH |
2580 | static void |
2581 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
2582 | smtp_transport_options_block * ob) | |
2583 | { | |
3fb3231c | 2584 | if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 2585 | { |
4af0d74a | 2586 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 2587 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2588 | string_domain_utf8_to_alabel(host->name, NULL); |
2589 | #else | |
2590 | host->name; | |
2591 | #endif | |
aa2a70ba JH |
2592 | DEBUG(D_tls) |
2593 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
2594 | state->exp_tls_verify_cert_hostnames); | |
2595 | } | |
2596 | } | |
aa2a70ba JH |
2597 | |
2598 | ||
899b8bbc JH |
2599 | |
2600 | ||
2601 | #ifdef SUPPORT_DANE | |
2602 | /* Given our list of RRs from the TLSA lookup, build a lookup block in | |
2603 | GnuTLS-DANE's preferred format. Hang it on the state str for later | |
2604 | use in DANE verification. | |
2605 | ||
2606 | We point at the dnsa data not copy it, so it must remain valid until | |
2607 | after verification is done.*/ | |
2608 | ||
3674140c | 2609 | static BOOL |
899b8bbc JH |
2610 | dane_tlsa_load(exim_gnutls_state_st * state, dns_answer * dnsa) |
2611 | { | |
899b8bbc JH |
2612 | dns_scan dnss; |
2613 | int i; | |
2614 | const char ** dane_data; | |
2615 | int * dane_data_len; | |
2616 | ||
d7978c0f JH |
2617 | i = 1; |
2618 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; | |
899b8bbc JH |
2619 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
2620 | ) if (rr->type == T_TLSA) i++; | |
2621 | ||
f3ebb786 JH |
2622 | dane_data = store_get(i * sizeof(uschar *), FALSE); |
2623 | dane_data_len = store_get(i * sizeof(int), FALSE); | |
899b8bbc | 2624 | |
d7978c0f JH |
2625 | i = 0; |
2626 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; | |
899b8bbc | 2627 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
1b76ad22 | 2628 | ) if (rr->type == T_TLSA && rr->size > 3) |
899b8bbc JH |
2629 | { |
2630 | const uschar * p = rr->data; | |
f3ebb786 | 2631 | /*XXX need somehow to mark rr and its data as tainted. Doues this mean copying it? */ |
3674140c JH |
2632 | uint8_t usage = p[0], sel = p[1], type = p[2]; |
2633 | ||
2634 | DEBUG(D_tls) | |
2635 | debug_printf("TLSA: %d %d %d size %d\n", usage, sel, type, rr->size); | |
2636 | ||
94c13285 JH |
2637 | if ( (usage != DANESSL_USAGE_DANE_TA && usage != DANESSL_USAGE_DANE_EE) |
2638 | || (sel != 0 && sel != 1) | |
2639 | ) | |
2640 | continue; | |
3674140c JH |
2641 | switch(type) |
2642 | { | |
2643 | case 0: /* Full: cannot check at present */ | |
2644 | break; | |
2645 | case 1: if (rr->size != 3 + 256/8) continue; /* sha2-256 */ | |
2646 | break; | |
2647 | case 2: if (rr->size != 3 + 512/8) continue; /* sha2-512 */ | |
2648 | break; | |
2649 | default: continue; | |
2650 | } | |
899b8bbc JH |
2651 | |
2652 | tls_out.tlsa_usage |= 1<<usage; | |
48224640 | 2653 | dane_data[i] = CS p; |
899b8bbc JH |
2654 | dane_data_len[i++] = rr->size; |
2655 | } | |
3674140c JH |
2656 | |
2657 | if (!i) return FALSE; | |
2658 | ||
899b8bbc JH |
2659 | dane_data[i] = NULL; |
2660 | dane_data_len[i] = 0; | |
2661 | ||
2662 | state->dane_data = (char * const *)dane_data; | |
2663 | state->dane_data_len = dane_data_len; | |
3674140c | 2664 | return TRUE; |
899b8bbc JH |
2665 | } |
2666 | #endif | |
2667 | ||
2668 | ||
2669 | ||
b10c87b3 JH |
2670 | #ifdef EXPERIMENTAL_TLS_RESUME |
2671 | /* On the client, get any stashed session for the given IP from hints db | |
2672 | and apply it to the ssl-connection for attempted resumption. Although | |
2673 | there is a gnutls_session_ticket_enable_client() interface it is | |
2674 | documented as unnecessary (as of 3.6.7) as "session tickets are emabled | |
2675 | by deafult". There seems to be no way to disable them, so even hosts not | |
2676 | enabled by the transport option will be sent a ticket request. We will | |
2677 | however avoid storing and retrieving session information. */ | |
2678 | ||
2679 | static void | |
2680 | tls_retrieve_session(tls_support * tlsp, gnutls_session_t session, | |
2681 | host_item * host, smtp_transport_options_block * ob) | |
2682 | { | |
2683 | tlsp->resumption = RESUME_SUPPORTED; | |
2684 | if (verify_check_given_host(CUSS &ob->tls_resumption_hosts, host) == OK) | |
2685 | { | |
2686 | dbdata_tls_session * dt; | |
2687 | int len, rc; | |
2688 | open_db dbblock, * dbm_file; | |
2689 | ||
2690 | DEBUG(D_tls) | |
2691 | debug_printf("check for resumable session for %s\n", host->address); | |
2692 | tlsp->host_resumable = TRUE; | |
2693 | tlsp->resumption |= RESUME_CLIENT_REQUESTED; | |
2694 | if ((dbm_file = dbfn_open(US"tls", O_RDONLY, &dbblock, FALSE, FALSE))) | |
2695 | { | |
dea4b568 JH |
2696 | /* Key for the db is the IP. We'd like to filter the retrieved session |
2697 | for ticket advisory expiry, but 3.6.1 seems to give no access to that */ | |
2698 | ||
b10c87b3 JH |
2699 | if ((dt = dbfn_read_with_length(dbm_file, host->address, &len))) |
2700 | if (!(rc = gnutls_session_set_data(session, | |
2701 | CUS dt->session, (size_t)len - sizeof(dbdata_tls_session)))) | |
2702 | { | |
2703 | DEBUG(D_tls) debug_printf("good session\n"); | |
2704 | tlsp->resumption |= RESUME_CLIENT_SUGGESTED; | |
2705 | } | |
2706 | else DEBUG(D_tls) debug_printf("setting session resumption data: %s\n", | |
2707 | US gnutls_strerror(rc)); | |
2708 | dbfn_close(dbm_file); | |
2709 | } | |
2710 | } | |
2711 | } | |
2712 | ||
2713 | ||
2714 | static void | |
2715 | tls_save_session(tls_support * tlsp, gnutls_session_t session, const host_item * host) | |
2716 | { | |
2717 | /* TLS 1.2 - we get both the callback and the direct posthandshake call, | |
2718 | but this flag is not set until the second. TLS 1.3 it's the other way about. | |
2719 | Keep both calls as the session data cannot be extracted before handshake | |
2720 | completes. */ | |
2721 | ||
2722 | if (gnutls_session_get_flags(session) & GNUTLS_SFLAGS_SESSION_TICKET) | |
2723 | { | |
2724 | gnutls_datum_t tkt; | |
2725 | int rc; | |
2726 | ||
2727 | DEBUG(D_tls) debug_printf("server offered session ticket\n"); | |
2728 | tlsp->ticket_received = TRUE; | |
2729 | tlsp->resumption |= RESUME_SERVER_TICKET; | |
2730 | ||
2731 | if (tlsp->host_resumable) | |
2732 | if (!(rc = gnutls_session_get_data2(session, &tkt))) | |
2733 | { | |
2734 | open_db dbblock, * dbm_file; | |
2735 | int dlen = sizeof(dbdata_tls_session) + tkt.size; | |
f3ebb786 | 2736 | dbdata_tls_session * dt = store_get(dlen, TRUE); |
b10c87b3 JH |
2737 | |
2738 | DEBUG(D_tls) debug_printf("session data size %u\n", (unsigned)tkt.size); | |
2739 | memcpy(dt->session, tkt.data, tkt.size); | |
2740 | gnutls_free(tkt.data); | |
2741 | ||
2742 | if ((dbm_file = dbfn_open(US"tls", O_RDWR, &dbblock, FALSE, FALSE))) | |
2743 | { | |
2744 | /* key for the db is the IP */ | |
2745 | dbfn_delete(dbm_file, host->address); | |
2746 | dbfn_write(dbm_file, host->address, dt, dlen); | |
2747 | dbfn_close(dbm_file); | |
2748 | ||
2749 | DEBUG(D_tls) | |
2750 | debug_printf("wrote session db (len %u)\n", (unsigned)dlen); | |
2751 | } | |
2752 | } | |
2753 | else DEBUG(D_tls) | |
2754 | debug_printf("extract session data: %s\n", US gnutls_strerror(rc)); | |
2755 | } | |
2756 | } | |
2757 | ||
2758 | ||
2759 | /* With a TLS1.3 session, the ticket(s) are not seen until | |
2760 | the first data read is attempted. And there's often two of them. | |
2761 | Pick them up with this callback. We are also called for 1.2 | |
2762 | but we do nothing. | |
2763 | */ | |
2764 | static int | |
2765 | tls_client_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
2766 | unsigned incoming, const gnutls_datum_t * msg) | |
2767 | { | |
2768 | exim_gnutls_state_st * state = gnutls_session_get_ptr(sess); | |
2769 | tls_support * tlsp = state->tlsp; | |
2770 | ||
2771 | DEBUG(D_tls) debug_printf("newticket cb\n"); | |
2772 | ||
2773 | if (!tlsp->ticket_received) | |
2774 | tls_save_session(tlsp, sess, state->host); | |
2775 | return 0; | |
2776 | } | |
2777 | ||
2778 | ||
2779 | static void | |
2780 | tls_client_resume_prehandshake(exim_gnutls_state_st * state, | |
2781 | tls_support * tlsp, host_item * host, | |
2782 | smtp_transport_options_block * ob) | |
2783 | { | |
2784 | gnutls_session_set_ptr(state->session, state); | |
2785 | gnutls_handshake_set_hook_function(state->session, | |
2786 | GNUTLS_HANDSHAKE_NEW_SESSION_TICKET, GNUTLS_HOOK_POST, tls_client_ticket_cb); | |
2787 | ||
2788 | tls_retrieve_session(tlsp, state->session, host, ob); | |
2789 | } | |
2790 | ||
2791 | static void | |
2792 | tls_client_resume_posthandshake(exim_gnutls_state_st * state, | |
2793 | tls_support * tlsp, host_item * host) | |
2794 | { | |
2795 | if (gnutls_session_is_resumed(state->session)) | |
2796 | { | |
2797 | DEBUG(D_tls) debug_printf("Session resumed\n"); | |
2798 | tlsp->resumption |= RESUME_USED; | |
2799 | } | |
2800 | ||
2801 | tls_save_session(tlsp, state->session, host); | |
2802 | } | |
2803 | #endif /* EXPERIMENTAL_TLS_RESUME */ | |
2804 | ||
2805 | ||
059ec3d9 PH |
2806 | /************************************************* |
2807 | * Start a TLS session in a client * | |
2808 | *************************************************/ | |
2809 | ||
2810 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2811 | ||
2812 | Arguments: | |
c05bdbd6 JH |
2813 | cctx connection context |
2814 | conn_args connection details | |
2815 | cookie datum for randomness (not used) | |
2816 | tlsp record details of channel configuration here; must be non-NULL | |
2817 | errstr error string pointer | |
2818 | ||
2819 | Returns: TRUE for success with TLS session context set in smtp context, | |
2820 | FALSE on error | |
059ec3d9 PH |
2821 | */ |
2822 | ||
c05bdbd6 JH |
2823 | BOOL |
2824 | tls_client_start(client_conn_ctx * cctx, smtp_connect_args * conn_args, | |
2825 | void * cookie ARG_UNUSED, | |
2826 | tls_support * tlsp, uschar ** errstr) | |
059ec3d9 | 2827 | { |
c05bdbd6 JH |
2828 | host_item * host = conn_args->host; /* for msgs and option-tests */ |
2829 | transport_instance * tb = conn_args->tblock; /* always smtp or NULL */ | |
2830 | smtp_transport_options_block * ob = tb | |
afdb5e9c JH |
2831 | ? (smtp_transport_options_block *)tb->options_block |
2832 | : &smtp_transport_option_defaults; | |
059ec3d9 | 2833 | int rc; |
899b8bbc | 2834 | exim_gnutls_state_st * state = NULL; |
c05bdbd6 | 2835 | uschar * cipher_list = NULL; |
74f1a423 | 2836 | |
f2de3a33 | 2837 | #ifndef DISABLE_OCSP |
5130845b | 2838 | BOOL require_ocsp = |
3fb3231c | 2839 | verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; |
44662487 | 2840 | BOOL request_ocsp = require_ocsp ? TRUE |
3fb3231c | 2841 | : verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 2842 | #endif |
059ec3d9 | 2843 | |
c05bdbd6 | 2844 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", cctx->sock); |
059ec3d9 | 2845 | |
5ec37a55 | 2846 | #ifdef SUPPORT_DANE |
c05bdbd6 JH |
2847 | /* If dane is flagged, have either request or require dane for this host, and |
2848 | a TLSA record found. Therefore, dane verify required. Which implies cert must | |
2849 | be requested and supplied, dane verify must pass, and cert verify irrelevant | |
2850 | (incl. hostnames), and (caller handled) require_tls */ | |
2851 | ||
2852 | if (conn_args->dane && ob->dane_require_tls_ciphers) | |
5ec37a55 PP |
2853 | { |
2854 | /* not using expand_check_tlsvar because not yet in state */ | |
2855 | if (!expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2856 | &cipher_list, errstr)) | |
c05bdbd6 | 2857 | return FALSE; |
cf260049 JH |
2858 | cipher_list = cipher_list && *cipher_list |
2859 | ? ob->dane_require_tls_ciphers : ob->tls_require_ciphers; | |
5ec37a55 PP |
2860 | } |
2861 | #endif | |
2862 | ||
2863 | if (!cipher_list) | |
2864 | cipher_list = ob->tls_require_ciphers; | |
2865 | ||
d85cdeb5 JH |
2866 | { |
2867 | #ifdef MEASURE_TIMING | |
2868 | struct timeval t0; | |
2869 | gettimeofday(&t0, NULL); | |
2870 | #endif | |
2871 | ||
2872 | if (tls_init(host, ob->tls_certificate, ob->tls_privatekey, | |
2873 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
2874 | cipher_list, &state, tlsp, errstr) != OK) | |
2875 | return FALSE; | |
2876 | ||
2877 | #ifdef MEASURE_TIMING | |
2878 | report_time_since(&t0, US"client tls_init (delta)"); | |
2879 | #endif | |
2880 | } | |
059ec3d9 | 2881 | |
54c90be1 | 2882 | { |
65867078 JH |
2883 | int dh_min_bits = ob->tls_dh_min_bits; |
2884 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2885 | { | |
2886 | DEBUG(D_tls) | |
2887 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2888 | " clamping %d up to %d\n", | |
2889 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2890 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2891 | } | |
54c90be1 | 2892 | |
65867078 JH |
2893 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2894 | " acceptable bits to %d\n", | |
2895 | dh_min_bits); | |
2896 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2897 | } | |
83da1223 | 2898 | |
94431adb | 2899 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2900 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2901 | the specified host patterns if one of them is defined */ | |
2902 | ||
899b8bbc | 2903 | #ifdef SUPPORT_DANE |
c05bdbd6 | 2904 | if (conn_args->dane && dane_tlsa_load(state, &conn_args->tlsa_dnsa)) |
899b8bbc JH |
2905 | { |
2906 | DEBUG(D_tls) | |
2907 | debug_printf("TLS: server certificate DANE required.\n"); | |
2908 | state->verify_requirement = VERIFY_DANE; | |
2909 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
899b8bbc JH |
2910 | } |
2911 | else | |
2912 | #endif | |
2913 | if ( ( state->exp_tls_verify_certificates | |
2914 | && !ob->tls_verify_hosts | |
2915 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2916 | ) | |
3fb3231c | 2917 | || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK |
899b8bbc | 2918 | ) |
17c76198 | 2919 | { |
aa2a70ba | 2920 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2921 | DEBUG(D_tls) |
2922 | debug_printf("TLS: server certificate verification required.\n"); | |
2923 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2924 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2925 | } | |
3fb3231c | 2926 | else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2927 | { |
aa2a70ba | 2928 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2929 | DEBUG(D_tls) |
2930 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2931 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2932 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2933 | } | |
2934 | else | |
2935 | { | |
e51c7be2 JH |
2936 | DEBUG(D_tls) |
2937 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2938 | state->verify_requirement = VERIFY_NONE; |
2939 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2940 | } |
059ec3d9 | 2941 | |
f2de3a33 JH |
2942 | #ifndef DISABLE_OCSP |
2943 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2944 | if (request_ocsp) |
9d1c15ef JH |
2945 | { |
2946 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2947 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2948 | NULL, 0, NULL)) != OK) | |
74f1a423 | 2949 | { |
452a164f | 2950 | tls_error_gnu(US"cert-status-req", rc, state->host, errstr); |
c05bdbd6 | 2951 | return FALSE; |
74f1a423 JH |
2952 | } |
2953 | tlsp->ocsp = OCSP_NOT_RESP; | |
9d1c15ef | 2954 | } |
2b4a568d JH |
2955 | #endif |
2956 | ||
b10c87b3 JH |
2957 | #ifdef EXPERIMENTAL_TLS_RESUME |
2958 | tls_client_resume_prehandshake(state, tlsp, host, ob); | |
2959 | #endif | |
2960 | ||
0cbf2b82 | 2961 | #ifndef DISABLE_EVENT |
afdb5e9c | 2962 | if (tb && tb->event_action) |
a7538db1 | 2963 | { |
774ef2d7 | 2964 | state->event_action = tb->event_action; |
a7538db1 | 2965 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2966 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2967 | } |
2968 | #endif | |
2969 | ||
c05bdbd6 JH |
2970 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) cctx->sock); |
2971 | state->fd_in = cctx->sock; | |
2972 | state->fd_out = cctx->sock; | |
059ec3d9 | 2973 | |
9d1c15ef | 2974 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2975 | /* There doesn't seem to be a built-in timeout on connection. */ |
2976 | ||
2977 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2978 | ALARM(ob->command_timeout); |
17c76198 | 2979 | do |
17c76198 | 2980 | rc = gnutls_handshake(state->session); |
f1fed05b | 2981 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
c2a1bba0 | 2982 | ALARM_CLR(0); |
059ec3d9 | 2983 | |
4fe99a6c | 2984 | if (rc != GNUTLS_E_SUCCESS) |
74f1a423 | 2985 | { |
60d10ce7 JH |
2986 | if (sigalrm_seen) |
2987 | { | |
2988 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
48224640 | 2989 | tls_error(US"gnutls_handshake", US"timed out", state->host, errstr); |
60d10ce7 JH |
2990 | } |
2991 | else | |
452a164f | 2992 | tls_error_gnu(US"gnutls_handshake", rc, state->host, errstr); |
c05bdbd6 | 2993 | return FALSE; |
74f1a423 | 2994 | } |
4fe99a6c | 2995 | |
dc6d1769 | 2996 | DEBUG(D_tls) post_handshake_debug(state); |
059ec3d9 | 2997 | |
17c76198 | 2998 | /* Verify late */ |
059ec3d9 | 2999 | |
899b8bbc | 3000 | if (!verify_certificate(state, errstr)) |
74f1a423 JH |
3001 | { |
3002 | tls_error(US"certificate verification failed", *errstr, state->host, errstr); | |
c05bdbd6 | 3003 | return FALSE; |
74f1a423 | 3004 | } |
059ec3d9 | 3005 | |
17ba0f52 | 3006 | #ifdef GNUTLS_SFLAGS_EXT_MASTER_SECRET |
1c519e07 JH |
3007 | if (gnutls_session_get_flags(state->session) & GNUTLS_SFLAGS_EXT_MASTER_SECRET) |
3008 | tlsp->ext_master_secret = TRUE; | |
17ba0f52 | 3009 | #endif |
1c519e07 | 3010 | |
f2de3a33 | 3011 | #ifndef DISABLE_OCSP |
7a501c87 | 3012 | if (request_ocsp) |
2b4a568d JH |
3013 | { |
3014 | DEBUG(D_tls) | |
3015 | { | |
3016 | gnutls_datum_t stapling; | |
3017 | gnutls_ocsp_resp_t resp; | |
3018 | gnutls_datum_t printed; | |
e326959e JH |
3019 | unsigned idx = 0; |
3020 | ||
3021 | for (; | |
3022 | # ifdef GNUTLS_OCSP_STATUS_REQUEST_GET2 | |
3023 | (rc = gnutls_ocsp_status_request_get2(state->session, idx, &stapling)) == 0; | |
3024 | #else | |
3025 | (rc = gnutls_ocsp_status_request_get(state->session, &stapling)) == 0; | |
3026 | #endif | |
3027 | idx++) | |
3028 | if ( (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
3029 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
3030 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_COMPACT, &printed)) == 0 | |
3031 | ) | |
3032 | { | |
3033 | debug_printf("%.4096s", printed.data); | |
3034 | gnutls_free(printed.data); | |
3035 | } | |
3036 | else | |
3037 | (void) tls_error_gnu(US"ocsp decode", rc, state->host, errstr); | |
3038 | if (idx == 0 && rc) | |
452a164f | 3039 | (void) tls_error_gnu(US"ocsp decode", rc, state->host, errstr); |
2b4a568d JH |
3040 | } |
3041 | ||
2b4a568d | 3042 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 | 3043 | { |
74f1a423 JH |
3044 | tlsp->ocsp = OCSP_FAILED; |
3045 | tls_error(US"certificate status check failed", NULL, state->host, errstr); | |
7a501c87 JH |
3046 | if (require_ocsp) |
3047 | return FALSE; | |
3048 | } | |
3049 | else | |
3050 | { | |
3051 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); | |
3052 | tlsp->ocsp = OCSP_VFIED; | |
018058b2 | 3053 | } |
2b4a568d JH |
3054 | } |
3055 | #endif | |
3056 | ||
b10c87b3 JH |
3057 | #ifdef EXPERIMENTAL_TLS_RESUME |
3058 | tls_client_resume_posthandshake(state, tlsp, host); | |
3059 | #endif | |
059ec3d9 | 3060 | |
4fe99a6c | 3061 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 3062 | |
9d1c15ef | 3063 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 3064 | |
c05bdbd6 JH |
3065 | cctx->tls_ctx = state; |
3066 | return TRUE; | |
059ec3d9 PH |
3067 | } |
3068 | ||
3069 | ||
3070 | ||
17c76198 | 3071 | |
059ec3d9 | 3072 | /************************************************* |
17c76198 | 3073 | * Close down a TLS session * |
059ec3d9 PH |
3074 | *************************************************/ |
3075 | ||
17c76198 PP |
3076 | /* This is also called from within a delivery subprocess forked from the |
3077 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
3078 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 3079 | |
dec766a1 | 3080 | Arguments: |
74f1a423 | 3081 | ct_ctx client context pointer, or NULL for the one global server context |
dec766a1 | 3082 | shutdown 1 if TLS close-alert is to be sent, |
afdb5e9c | 3083 | 2 if also response to be waited for |
dec766a1 | 3084 | |
17c76198 | 3085 | Returns: nothing |
059ec3d9 PH |
3086 | */ |
3087 | ||
17c76198 | 3088 | void |
74f1a423 | 3089 | tls_close(void * ct_ctx, int shutdown) |
059ec3d9 | 3090 | { |
74f1a423 | 3091 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
bd231acd | 3092 | tls_support * tlsp = state->tlsp; |
059ec3d9 | 3093 | |
bd231acd | 3094 | if (!tlsp || tlsp->active.sock < 0) return; /* TLS was not active */ |
17c76198 PP |
3095 | |
3096 | if (shutdown) | |
3097 | { | |
dec766a1 WB |
3098 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", |
3099 | shutdown > 1 ? " (with response-wait)" : ""); | |
3100 | ||
c2a1bba0 | 3101 | ALARM(2); |
dec766a1 | 3102 | gnutls_bye(state->session, shutdown > 1 ? GNUTLS_SHUT_RDWR : GNUTLS_SHUT_WR); |
c2a1bba0 | 3103 | ALARM_CLR(0); |
17c76198 PP |
3104 | } |
3105 | ||
bd231acd JH |
3106 | if (!ct_ctx) /* server */ |
3107 | { | |
3108 | receive_getc = smtp_getc; | |
3109 | receive_getbuf = smtp_getbuf; | |
3110 | receive_get_cache = smtp_get_cache; | |
3111 | receive_ungetc = smtp_ungetc; | |
3112 | receive_feof = smtp_feof; | |
3113 | receive_ferror = smtp_ferror; | |
3114 | receive_smtp_buffered = smtp_buffered; | |
3115 | } | |
3116 | ||
17c76198 | 3117 | gnutls_deinit(state->session); |
ed62aae3 HSHR |
3118 | gnutls_certificate_free_credentials(state->x509_cred); |
3119 | ||
bd231acd JH |
3120 | tlsp->active.sock = -1; |
3121 | tlsp->active.tls_ctx = NULL; | |
3122 | /* Leave bits, peercert, cipher, peerdn, certificate_verified set, for logging */ | |
b1a32a3c | 3123 | tlsp->channelbinding = NULL; |
bd231acd | 3124 | |
17c76198 | 3125 | |
b808677c | 3126 | if (state->xfer_buffer) store_free(state->xfer_buffer); |
17c76198 | 3127 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
059ec3d9 PH |
3128 | } |
3129 | ||
3130 | ||
3131 | ||
17c76198 | 3132 | |
0d81dabc JH |
3133 | static BOOL |
3134 | tls_refill(unsigned lim) | |
3135 | { | |
3136 | exim_gnutls_state_st * state = &state_server; | |
3137 | ssize_t inbytes; | |
3138 | ||
3139 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
3140 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
3141 | ||
f1fed05b | 3142 | sigalrm_seen = FALSE; |
c2a1bba0 | 3143 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
4896a319 AM |
3144 | |
3145 | do | |
3146 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
3147 | MIN(ssl_xfer_buffer_size, lim)); | |
3148 | while (inbytes == GNUTLS_E_AGAIN); | |
3149 | ||
c2a1bba0 | 3150 | if (smtp_receive_timeout > 0) ALARM_CLR(0); |
9723f966 JH |
3151 | |
3152 | if (had_command_timeout) /* set by signal handler */ | |
3153 | smtp_command_timeout_exit(); /* does not return */ | |
3154 | if (had_command_sigterm) | |
3155 | smtp_command_sigterm_exit(); | |
3156 | if (had_data_timeout) | |
3157 | smtp_data_timeout_exit(); | |
3158 | if (had_data_sigint) | |
3159 | smtp_data_sigint_exit(); | |
3160 | ||
3161 | /* Timeouts do not get this far. A zero-byte return appears to mean that the | |
3162 | TLS session has been closed down, not that the socket itself has been closed | |
3163 | down. Revert to non-TLS handling. */ | |
0d81dabc JH |
3164 | |
3165 | if (sigalrm_seen) | |
3166 | { | |
3167 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
8b77d27a | 3168 | state->xfer_error = TRUE; |
0d81dabc JH |
3169 | return FALSE; |
3170 | } | |
3171 | ||
3172 | else if (inbytes == 0) | |
3173 | { | |
3174 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
bd231acd | 3175 | tls_close(NULL, TLS_NO_SHUTDOWN); |
0d81dabc JH |
3176 | return FALSE; |
3177 | } | |
3178 | ||
3179 | /* Handle genuine errors */ | |
3180 | ||
3181 | else if (inbytes < 0) | |
3182 | { | |
95f52235 | 3183 | DEBUG(D_tls) debug_printf("%s: err from gnutls_record_recv\n", __FUNCTION__); |
0d81dabc | 3184 | record_io_error(state, (int) inbytes, US"recv", NULL); |
8b77d27a | 3185 | state->xfer_error = TRUE; |
0d81dabc JH |
3186 | return FALSE; |
3187 | } | |
3188 | #ifndef DISABLE_DKIM | |
3189 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
3190 | #endif | |
3191 | state->xfer_buffer_hwm = (int) inbytes; | |
3192 | state->xfer_buffer_lwm = 0; | |
3193 | return TRUE; | |
3194 | } | |
3195 | ||
059ec3d9 PH |
3196 | /************************************************* |
3197 | * TLS version of getc * | |
3198 | *************************************************/ | |
3199 | ||
3200 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
3201 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 3202 | Only used by the server-side TLS. |
059ec3d9 | 3203 | |
17c76198 PP |
3204 | This feeds DKIM and should be used for all message-body reads. |
3205 | ||
aded2255 | 3206 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 PH |
3207 | Returns: the next character or EOF |
3208 | */ | |
3209 | ||
3210 | int | |
bd8fbe36 | 3211 | tls_getc(unsigned lim) |
059ec3d9 | 3212 | { |
0d81dabc | 3213 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 3214 | |
0d81dabc JH |
3215 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
3216 | if (!tls_refill(lim)) | |
3217 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 3218 | |
0d81dabc | 3219 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 3220 | |
0d81dabc JH |
3221 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
3222 | } | |
059ec3d9 | 3223 | |
0d81dabc JH |
3224 | uschar * |
3225 | tls_getbuf(unsigned * len) | |
3226 | { | |
3227 | exim_gnutls_state_st * state = &state_server; | |
3228 | unsigned size; | |
3229 | uschar * buf; | |
059ec3d9 | 3230 | |
0d81dabc JH |
3231 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
3232 | if (!tls_refill(*len)) | |
059ec3d9 | 3233 | { |
0d81dabc JH |
3234 | if (!state->xfer_error) return smtp_getbuf(len); |
3235 | *len = 0; | |
3236 | return NULL; | |
059ec3d9 | 3237 | } |
059ec3d9 | 3238 | |
0d81dabc JH |
3239 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
3240 | size = *len; | |
3241 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
3242 | state->xfer_buffer_lwm += size; | |
3243 | *len = size; | |
3244 | return buf; | |
059ec3d9 PH |
3245 | } |
3246 | ||
0d81dabc | 3247 | |
584e96c6 JH |
3248 | void |
3249 | tls_get_cache() | |
3250 | { | |
9960d1e5 | 3251 | #ifndef DISABLE_DKIM |
584e96c6 JH |
3252 | exim_gnutls_state_st * state = &state_server; |
3253 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
3254 | if (n > 0) | |
3255 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 3256 | #endif |
9960d1e5 | 3257 | } |
584e96c6 | 3258 | |
059ec3d9 | 3259 | |
925ac8e4 JH |
3260 | BOOL |
3261 | tls_could_read(void) | |
3262 | { | |
3263 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
3264 | || gnutls_record_check_pending(state_server.session) > 0; | |
3265 | } | |
3266 | ||
3267 | ||
059ec3d9 | 3268 | |
17c76198 | 3269 | |
059ec3d9 PH |
3270 | /************************************************* |
3271 | * Read bytes from TLS channel * | |
3272 | *************************************************/ | |
3273 | ||
17c76198 PP |
3274 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
3275 | then the caller must feed DKIM. | |
817d9f57 | 3276 | |
059ec3d9 | 3277 | Arguments: |
74f1a423 | 3278 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
3279 | buff buffer of data |
3280 | len size of buffer | |
3281 | ||
3282 | Returns: the number of bytes read | |
afdb5e9c | 3283 | -1 after a failed read, including EOF |
059ec3d9 PH |
3284 | */ |
3285 | ||
3286 | int | |
74f1a423 | 3287 | tls_read(void * ct_ctx, uschar *buff, size_t len) |
059ec3d9 | 3288 | { |
74f1a423 | 3289 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
17c76198 | 3290 | ssize_t inbytes; |
059ec3d9 | 3291 | |
17c76198 PP |
3292 | if (len > INT_MAX) |
3293 | len = INT_MAX; | |
059ec3d9 | 3294 | |
17c76198 PP |
3295 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
3296 | DEBUG(D_tls) | |
3297 | debug_printf("*** PROBABLY A BUG *** " \ | |
3298 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
3299 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
3300 | ||
3301 | DEBUG(D_tls) | |
3302 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
3303 | state->session, buff, len); | |
3304 | ||
4896a319 AM |
3305 | do |
3306 | inbytes = gnutls_record_recv(state->session, buff, len); | |
3307 | while (inbytes == GNUTLS_E_AGAIN); | |
3308 | ||
059ec3d9 PH |
3309 | if (inbytes > 0) return inbytes; |
3310 | if (inbytes == 0) | |
3311 | { | |
3312 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
3313 | } | |
5fd28bb8 | 3314 | else |
4896a319 | 3315 | { |
95f52235 | 3316 | DEBUG(D_tls) debug_printf("%s: err from gnutls_record_recv\n", __FUNCTION__); |
4896a319 AM |
3317 | record_io_error(state, (int)inbytes, US"recv", NULL); |
3318 | } | |
059ec3d9 PH |
3319 | |
3320 | return -1; | |
3321 | } | |
3322 | ||
3323 | ||
3324 | ||
17c76198 | 3325 | |
059ec3d9 PH |
3326 | /************************************************* |
3327 | * Write bytes down TLS channel * | |
3328 | *************************************************/ | |
3329 | ||
3330 | /* | |
3331 | Arguments: | |
74f1a423 | 3332 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
3333 | buff buffer of data |
3334 | len number of bytes | |
925ac8e4 | 3335 | more more data expected soon |
059ec3d9 | 3336 | |
30398c06 JH |
3337 | Calling with len zero and more unset will flush buffered writes. The buff |
3338 | argument can be null for that case. | |
3339 | ||
059ec3d9 PH |
3340 | Returns: the number of bytes after a successful write, |
3341 | -1 after a failed write | |
3342 | */ | |
3343 | ||
3344 | int | |
74f1a423 | 3345 | tls_write(void * ct_ctx, const uschar * buff, size_t len, BOOL more) |
059ec3d9 | 3346 | { |
17c76198 PP |
3347 | ssize_t outbytes; |
3348 | size_t left = len; | |
74f1a423 | 3349 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
925ac8e4 JH |
3350 | #ifdef SUPPORT_CORK |
3351 | static BOOL corked = FALSE; | |
3352 | ||
3353 | if (more && !corked) gnutls_record_cork(state->session); | |
3354 | #endif | |
3355 | ||
3356 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
3357 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 3358 | |
059ec3d9 PH |
3359 | while (left > 0) |
3360 | { | |
17c76198 PP |
3361 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
3362 | buff, left); | |
4896a319 AM |
3363 | |
3364 | do | |
3365 | outbytes = gnutls_record_send(state->session, buff, left); | |
3366 | while (outbytes == GNUTLS_E_AGAIN); | |
059ec3d9 | 3367 | |
17c76198 | 3368 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
3369 | if (outbytes < 0) |
3370 | { | |
1b76ad22 | 3371 | DEBUG(D_tls) debug_printf("%s: gnutls_record_send err\n", __FUNCTION__); |
17c76198 | 3372 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
3373 | return -1; |
3374 | } | |
3375 | if (outbytes == 0) | |
3376 | { | |
17c76198 | 3377 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
3378 | return -1; |
3379 | } | |
3380 | ||
3381 | left -= outbytes; | |
3382 | buff += outbytes; | |
3383 | } | |
3384 | ||
17c76198 PP |
3385 | if (len > INT_MAX) |
3386 | { | |
3387 | DEBUG(D_tls) | |
3388 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
3389 | len); | |
3390 | len = INT_MAX; | |
3391 | } | |
3392 | ||
925ac8e4 JH |
3393 | #ifdef SUPPORT_CORK |
3394 | if (more != corked) | |
3395 | { | |
3396 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
3397 | corked = more; | |
3398 | } | |
3399 | #endif | |
3400 | ||
17c76198 | 3401 | return (int) len; |
059ec3d9 PH |
3402 | } |
3403 | ||
3404 | ||
3405 | ||
17c76198 | 3406 | |
059ec3d9 | 3407 | /************************************************* |
17c76198 | 3408 | * Random number generation * |
059ec3d9 PH |
3409 | *************************************************/ |
3410 | ||
17c76198 PP |
3411 | /* Pseudo-random number generation. The result is not expected to be |
3412 | cryptographically strong but not so weak that someone will shoot themselves | |
3413 | in the foot using it as a nonce in input in some email header scheme or | |
3414 | whatever weirdness they'll twist this into. The result should handle fork() | |
3415 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 3416 | |
17c76198 PP |
3417 | Arguments: |
3418 | max range maximum | |
3419 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
3420 | */ |
3421 | ||
af3498d6 | 3422 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
3423 | int |
3424 | vaguely_random_number(int max) | |
059ec3d9 | 3425 | { |
17c76198 PP |
3426 | unsigned int r; |
3427 | int i, needed_len; | |
17c76198 PP |
3428 | uschar smallbuf[sizeof(r)]; |
3429 | ||
3430 | if (max <= 1) | |
3431 | return 0; | |
3432 | ||
3433 | needed_len = sizeof(r); | |
3434 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
d7978c0f JH |
3435 | asked for a number less than 10. */ |
3436 | ||
17c76198 PP |
3437 | for (r = max, i = 0; r; ++i) |
3438 | r >>= 1; | |
3439 | i = (i + 7) / 8; | |
3440 | if (i < needed_len) | |
3441 | needed_len = i; | |
3442 | ||
3443 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
3444 | if (i < 0) | |
059ec3d9 | 3445 | { |
17c76198 PP |
3446 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
3447 | return vaguely_random_number_fallback(max); | |
3448 | } | |
3449 | r = 0; | |
d7978c0f JH |
3450 | for (uschar * p = smallbuf; needed_len; --needed_len, ++p) |
3451 | r = r * 256 + *p; | |
059ec3d9 | 3452 | |
17c76198 PP |
3453 | /* We don't particularly care about weighted results; if someone wants |
3454 | * smooth distribution and cares enough then they should submit a patch then. */ | |
3455 | return r % max; | |
059ec3d9 | 3456 | } |
af3498d6 PP |
3457 | #else /* HAVE_GNUTLS_RND */ |
3458 | int | |
3459 | vaguely_random_number(int max) | |
3460 | { | |
3461 | return vaguely_random_number_fallback(max); | |
3462 | } | |
3463 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 3464 | |
36f12725 NM |
3465 | |
3466 | ||
3467 | ||
3375e053 PP |
3468 | /************************************************* |
3469 | * Let tls_require_ciphers be checked at startup * | |
3470 | *************************************************/ | |
3471 | ||
3472 | /* The tls_require_ciphers option, if set, must be something which the | |
3473 | library can parse. | |
3474 | ||
3475 | Returns: NULL on success, or error message | |
3476 | */ | |
3477 | ||
3478 | uschar * | |
3479 | tls_validate_require_cipher(void) | |
3480 | { | |
3481 | int rc; | |
3482 | uschar *expciphers = NULL; | |
3483 | gnutls_priority_t priority_cache; | |
3484 | const char *errpos; | |
cf0c6164 | 3485 | uschar * dummy_errstr; |
3375e053 | 3486 | |
4d2a62a3 JH |
3487 | #ifdef GNUTLS_AUTO_GLOBAL_INIT |
3488 | # define validate_check_rc(Label) do { \ | |
3489 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) \ | |
3490 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
3491 | # define return_deinit(Label) do { return (Label); } while (0) | |
3492 | #else | |
3493 | # define validate_check_rc(Label) do { \ | |
3375e053 | 3494 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ |
4d2a62a3 JH |
3495 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) |
3496 | # define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
3497 | #endif | |
3375e053 PP |
3498 | |
3499 | if (exim_gnutls_base_init_done) | |
3500 | log_write(0, LOG_MAIN|LOG_PANIC, | |
3501 | "already initialised GnuTLS, Exim developer bug"); | |
3502 | ||
9f707b89 | 3503 | #if defined(HAVE_GNUTLS_PKCS11) && !defined(GNUTLS_AUTO_PKCS11_MANUAL) |
2519e60d | 3504 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
3505 | { |
3506 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
3507 | validate_check_rc(US"gnutls_pkcs11_init"); | |
3508 | } | |
3509 | #endif | |
4d2a62a3 | 3510 | #ifndef GNUTLS_AUTO_GLOBAL_INIT |
3375e053 PP |
3511 | rc = gnutls_global_init(); |
3512 | validate_check_rc(US"gnutls_global_init()"); | |
4d2a62a3 | 3513 | #endif |
3375e053 PP |
3514 | exim_gnutls_base_init_done = TRUE; |
3515 | ||
3516 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
3517 | return_deinit(NULL); | |
3518 | ||
cf0c6164 JH |
3519 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
3520 | &dummy_errstr)) | |
3375e053 PP |
3521 | return_deinit(US"failed to expand tls_require_ciphers"); |
3522 | ||
3523 | if (!(expciphers && *expciphers)) | |
3524 | return_deinit(NULL); | |
3525 | ||
3526 | DEBUG(D_tls) | |
3527 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
3528 | ||
3529 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
3530 | validate_check_rc(string_sprintf( | |
3531 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
3532 | expciphers, errpos - CS expciphers, errpos)); | |
3533 | ||
3534 | #undef return_deinit | |
3535 | #undef validate_check_rc | |
4d2a62a3 | 3536 | #ifndef GNUTLS_AUTO_GLOBAL_INIT |
3375e053 | 3537 | gnutls_global_deinit(); |
4d2a62a3 | 3538 | #endif |
3375e053 PP |
3539 | |
3540 | return NULL; | |
3541 | } | |
3542 | ||
3543 | ||
3544 | ||
3545 | ||
36f12725 NM |
3546 | /************************************************* |
3547 | * Report the library versions. * | |
3548 | *************************************************/ | |
3549 | ||
3550 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
3551 | ||
3552 | Arguments: a FILE* to print the results to | |
3553 | Returns: nothing | |
3554 | */ | |
3555 | ||
3556 | void | |
3557 | tls_version_report(FILE *f) | |
3558 | { | |
754a0503 PP |
3559 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
3560 | " Runtime: %s\n", | |
3561 | LIBGNUTLS_VERSION, | |
3562 | gnutls_check_version(NULL)); | |
36f12725 NM |
3563 | } |
3564 | ||
b10c87b3 | 3565 | #endif /*!MACRO_PREDEF*/ |
2b4a568d JH |
3566 | /* vi: aw ai sw=2 |
3567 | */ | |
059ec3d9 | 3568 | /* End of tls-gnu.c */ |