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 | |
73 | #if GNUTLS_VERSION_NUMBER >= 0x030500 | |
74 | # define SUPPORT_GNUTLS_KEYLOG | |
75 | #endif | |
47195144 JH |
76 | #if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP) |
77 | # define SUPPORT_SRV_OCSP_STACK | |
78 | #endif | |
c0635b6d JH |
79 | |
80 | #ifdef SUPPORT_DANE | |
81 | # if GNUTLS_VERSION_NUMBER >= 0x030000 | |
82 | # define DANESSL_USAGE_DANE_TA 2 | |
83 | # define DANESSL_USAGE_DANE_EE 3 | |
84 | # else | |
85 | # error GnuTLS version too early for DANE | |
86 | # endif | |
87 | # if GNUTLS_VERSION_NUMBER < 0x999999 | |
88 | # define GNUTLS_BROKEN_DANE_VALIDATION | |
89 | # endif | |
899b8bbc | 90 | #endif |
7e07527a | 91 | |
43e2db44 JH |
92 | #ifdef EXPERIMENTAL_TLS_RESUME |
93 | # if GNUTLS_VERSION_NUMBER < 0x030603 | |
94 | # error GNUTLS version too early for session-resumption | |
95 | # endif | |
96 | #endif | |
97 | ||
f2de3a33 | 98 | #ifndef DISABLE_OCSP |
2b4a568d JH |
99 | # include <gnutls/ocsp.h> |
100 | #endif | |
899b8bbc JH |
101 | #ifdef SUPPORT_DANE |
102 | # include <gnutls/dane.h> | |
103 | #endif | |
059ec3d9 | 104 | |
f1be21cf JH |
105 | #include "tls-cipher-stdname.c" |
106 | ||
107 | ||
b10c87b3 JH |
108 | #ifdef MACRO_PREDEF |
109 | void | |
110 | options_tls(void) | |
111 | { | |
112 | # ifdef EXPERIMENTAL_TLS_RESUME | |
113 | builtin_macro_create_var(US"_RESUME_DECODE", RESUME_DECODE_STRING ); | |
114 | # endif | |
115 | } | |
116 | #else | |
117 | ||
118 | ||
17c76198 | 119 | /* GnuTLS 2 vs 3 |
059ec3d9 | 120 | |
17c76198 PP |
121 | GnuTLS 3 only: |
122 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 123 | |
17c76198 PP |
124 | Changes: |
125 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
126 | */ | |
059ec3d9 | 127 | |
17c76198 | 128 | /* Local static variables for GnuTLS */ |
059ec3d9 | 129 | |
17c76198 | 130 | /* Values for verify_requirement */ |
059ec3d9 | 131 | |
e51c7be2 | 132 | enum peer_verify_requirement |
899b8bbc | 133 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED, VERIFY_DANE }; |
059ec3d9 | 134 | |
17c76198 PP |
135 | /* This holds most state for server or client; with this, we can set up an |
136 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
137 | over the TLS variables available for expansion. | |
059ec3d9 | 138 | |
17c76198 PP |
139 | Some of these correspond to variables in globals.c; those variables will |
140 | be set to point to content in one of these instances, as appropriate for | |
141 | the stage of the process lifetime. | |
059ec3d9 | 142 | |
389ca47a | 143 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 144 | */ |
059ec3d9 | 145 | |
17c76198 | 146 | typedef struct exim_gnutls_state { |
9d1c15ef | 147 | gnutls_session_t session; |
17c76198 | 148 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 149 | gnutls_priority_t priority_cache; |
17c76198 | 150 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
151 | int fd_in; |
152 | int fd_out; | |
153 | BOOL peer_cert_verified; | |
899b8bbc | 154 | BOOL peer_dane_verified; |
9d1c15ef JH |
155 | BOOL trigger_sni_changes; |
156 | BOOL have_set_peerdn; | |
5fd28bb8 | 157 | const struct host_item *host; /* NULL if server */ |
afdb5e9c | 158 | gnutls_x509_crt_t peercert; |
9d1c15ef JH |
159 | uschar *peerdn; |
160 | uschar *ciphersuite; | |
161 | uschar *received_sni; | |
17c76198 PP |
162 | |
163 | const uschar *tls_certificate; | |
164 | const uschar *tls_privatekey; | |
165 | const uschar *tls_sni; /* client send only, not received */ | |
166 | const uschar *tls_verify_certificates; | |
167 | const uschar *tls_crl; | |
168 | const uschar *tls_require_ciphers; | |
e51c7be2 | 169 | |
17c76198 PP |
170 | uschar *exp_tls_certificate; |
171 | uschar *exp_tls_privatekey; | |
17c76198 PP |
172 | uschar *exp_tls_verify_certificates; |
173 | uschar *exp_tls_crl; | |
174 | uschar *exp_tls_require_ciphers; | |
55414b25 | 175 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 176 | #ifndef DISABLE_EVENT |
a7538db1 JH |
177 | uschar *event_action; |
178 | #endif | |
899b8bbc JH |
179 | #ifdef SUPPORT_DANE |
180 | char * const * dane_data; | |
181 | const int * dane_data_len; | |
182 | #endif | |
17c76198 | 183 | |
389ca47a | 184 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 185 | |
17c76198 PP |
186 | uschar *xfer_buffer; |
187 | int xfer_buffer_lwm; | |
188 | int xfer_buffer_hwm; | |
8b77d27a JH |
189 | BOOL xfer_eof; /*XXX never gets set! */ |
190 | BOOL xfer_error; | |
17c76198 PP |
191 | } exim_gnutls_state_st; |
192 | ||
193 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
b10c87b3 | 194 | /* all elements not explicitly intialised here get 0/NULL/FALSE */ |
f2ed27cf JH |
195 | .fd_in = -1, |
196 | .fd_out = -1, | |
17c76198 | 197 | }; |
83da1223 | 198 | |
17c76198 PP |
199 | /* Not only do we have our own APIs which don't pass around state, assuming |
200 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
201 | for callbacks, or as part of the session, so we have to keep a "this is the | |
202 | context we're currently dealing with" pointer and rely upon being | |
203 | single-threaded to keep from processing data on an inbound TLS connection while | |
204 | talking to another TLS connection for an outbound check. This does mean that | |
205 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
206 | second connection. |
207 | XXX But see gnutls_session_get_ptr() | |
208 | */ | |
059ec3d9 | 209 | |
74f1a423 | 210 | static exim_gnutls_state_st state_server; |
059ec3d9 | 211 | |
17c76198 PP |
212 | /* dh_params are initialised once within the lifetime of a process using TLS; |
213 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
214 | don't want to repeat this. */ | |
83da1223 | 215 | |
17c76198 | 216 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 217 | |
dea4b568 | 218 | static int ssl_session_timeout = 7200; /* Two hours */ |
059ec3d9 | 219 | |
fc243e94 | 220 | static const uschar * const exim_default_gnutls_priority = US"NORMAL"; |
83da1223 | 221 | |
17c76198 | 222 | /* Guard library core initialisation */ |
83da1223 | 223 | |
17c76198 | 224 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 225 | |
4fb7df6d | 226 | #ifndef DISABLE_OCSP |
9196d5bf | 227 | static BOOL gnutls_buggy_ocsp = FALSE; |
e5489333 | 228 | static BOOL exim_testharness_disable_ocsp_validity_check = FALSE; |
4fb7df6d | 229 | #endif |
9196d5bf | 230 | |
b10c87b3 JH |
231 | #ifdef EXPERIMENTAL_TLS_RESUME |
232 | static gnutls_datum_t server_sessticket_key; | |
233 | #endif | |
059ec3d9 | 234 | |
17c76198 PP |
235 | /* ------------------------------------------------------------------------ */ |
236 | /* macros */ | |
83da1223 | 237 | |
17c76198 | 238 | #define MAX_HOST_LEN 255 |
83da1223 | 239 | |
17c76198 PP |
240 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
241 | the library logging; a value less than 0 disables the calls to set up logging | |
dc6d1769 JH |
242 | callbacks. GNuTLS also looks for an environment variable - except not for |
243 | setuid binaries, making it useless - "GNUTLS_DEBUG_LEVEL". | |
244 | Allegedly the testscript line "GNUTLS_DEBUG_LEVEL=9 sudo exim ..." would work, | |
245 | but the env var must be added to /etc/sudoers too. */ | |
2c17bb02 | 246 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
b1a4f234 | 247 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 248 | #endif |
83da1223 | 249 | |
2c17bb02 | 250 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 251 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 252 | #endif |
83da1223 | 253 | |
af3498d6 PP |
254 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
255 | can ask for a bit-strength. Without that, we stick to the constant we had | |
256 | before, for now. */ | |
2c17bb02 | 257 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 258 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 259 | #endif |
af3498d6 | 260 | |
cf0c6164 JH |
261 | #define expand_check_tlsvar(Varname, errstr) \ |
262 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 263 | |
17c76198 | 264 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
265 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
266 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
267 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
268 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
269 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
270 | * isn't available sometimes, so this needs to become a conditional | |
271 | * compilation; the sanest way to deal with this being a problem on | |
272 | * older OSes is to block it in the Local/Makefile with this compiler | |
273 | * definition */ | |
e51c7be2 JH |
274 | # ifndef AVOID_GNUTLS_PKCS11 |
275 | # define HAVE_GNUTLS_PKCS11 | |
276 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 277 | #endif |
83da1223 | 278 | |
af3498d6 PP |
279 | |
280 | ||
281 | ||
282 | /* ------------------------------------------------------------------------ */ | |
283 | /* Callback declarations */ | |
284 | ||
285 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
286 | static void exim_gnutls_logger_cb(int level, const char *message); | |
287 | #endif | |
288 | ||
289 | static int exim_sni_handling_cb(gnutls_session_t session); | |
290 | ||
e5489333 | 291 | #if !defined(DISABLE_OCSP) |
44662487 JH |
292 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
293 | gnutls_datum_t * ocsp_response); | |
294 | #endif | |
af3498d6 | 295 | |
e5489333 JH |
296 | #ifdef EXPERIMENTAL_TLS_RESUME |
297 | static int | |
298 | tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
299 | unsigned incoming, const gnutls_datum_t * msg); | |
300 | #endif | |
af3498d6 PP |
301 | |
302 | ||
b10c87b3 JH |
303 | /* Daemon one-time initialisation */ |
304 | void | |
305 | tls_daemon_init(void) | |
306 | { | |
307 | #ifdef EXPERIMENTAL_TLS_RESUME | |
308 | /* We are dependent on the GnuTLS implementation of the Session Ticket | |
309 | encryption; both the strength and the key rotation period. We hope that | |
310 | the strength at least matches that of the ciphersuite (but GnuTLS does not | |
311 | document this). */ | |
312 | ||
313 | static BOOL once = FALSE; | |
314 | if (once) return; | |
315 | once = TRUE; | |
316 | gnutls_session_ticket_key_generate(&server_sessticket_key); /* >= 2.10.0 */ | |
317 | if (f.running_in_test_harness) ssl_session_timeout = 6; | |
318 | #endif | |
319 | } | |
320 | ||
17c76198 PP |
321 | /* ------------------------------------------------------------------------ */ |
322 | /* Static functions */ | |
059ec3d9 PH |
323 | |
324 | /************************************************* | |
325 | * Handle TLS error * | |
326 | *************************************************/ | |
327 | ||
328 | /* Called from lots of places when errors occur before actually starting to do | |
329 | the TLS handshake, that is, while the session is still in clear. Always returns | |
330 | DEFER for a server and FAIL for a client so that most calls can use "return | |
331 | tls_error(...)" to do this processing and then give an appropriate return. A | |
332 | single function is used for both server and client, because it is called from | |
333 | some shared functions. | |
334 | ||
335 | Argument: | |
336 | prefix text to include in the logged error | |
7199e1ee TF |
337 | msg additional error string (may be NULL) |
338 | usually obtained from gnutls_strerror() | |
17c76198 PP |
339 | host NULL if setting up a server; |
340 | the connected host if setting up a client | |
cf0c6164 | 341 | errstr pointer to returned error string |
059ec3d9 PH |
342 | |
343 | Returns: OK/DEFER/FAIL | |
344 | */ | |
345 | ||
346 | static int | |
48224640 | 347 | tls_error(const uschar *prefix, const uschar *msg, const host_item *host, |
cf0c6164 | 348 | uschar ** errstr) |
059ec3d9 | 349 | { |
cf0c6164 | 350 | if (errstr) |
48224640 | 351 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : US""); |
cf0c6164 | 352 | return host ? FAIL : DEFER; |
059ec3d9 PH |
353 | } |
354 | ||
355 | ||
452a164f JH |
356 | static int |
357 | tls_error_gnu(const uschar *prefix, int err, const host_item *host, | |
358 | uschar ** errstr) | |
359 | { | |
360 | return tls_error(prefix, US gnutls_strerror(err), host, errstr); | |
361 | } | |
362 | ||
363 | static int | |
364 | tls_error_sys(const uschar *prefix, int err, const host_item *host, | |
365 | uschar ** errstr) | |
366 | { | |
367 | return tls_error(prefix, US strerror(err), host, errstr); | |
368 | } | |
059ec3d9 | 369 | |
17c76198 | 370 | |
059ec3d9 | 371 | /************************************************* |
17c76198 | 372 | * Deal with logging errors during I/O * |
059ec3d9 PH |
373 | *************************************************/ |
374 | ||
17c76198 | 375 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 376 | |
17c76198 PP |
377 | Argument: |
378 | state the current GnuTLS exim state container | |
379 | rc the GnuTLS error code, or 0 if it's a local error | |
380 | when text identifying read or write | |
95f52235 | 381 | text local error text when rc is 0 |
059ec3d9 | 382 | |
17c76198 | 383 | Returns: nothing |
059ec3d9 PH |
384 | */ |
385 | ||
17c76198 PP |
386 | static void |
387 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 388 | { |
48224640 | 389 | const uschar * msg; |
cf0c6164 | 390 | uschar * errstr; |
059ec3d9 | 391 | |
17c76198 | 392 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
95f52235 | 393 | msg = string_sprintf("A TLS fatal alert has been received: %s", |
17c76198 PP |
394 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); |
395 | else | |
48224640 | 396 | msg = US gnutls_strerror(rc); |
059ec3d9 | 397 | |
cf0c6164 JH |
398 | (void) tls_error(when, msg, state->host, &errstr); |
399 | ||
400 | if (state->host) | |
401 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
402 | state->host->name, state->host->address, errstr); | |
403 | else | |
404 | { | |
405 | uschar * conn_info = smtp_get_connection_info(); | |
406 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
407 | /* I'd like to get separated H= here, but too hard for now */ | |
408 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
409 | } | |
17c76198 | 410 | } |
059ec3d9 | 411 | |
059ec3d9 | 412 | |
059ec3d9 | 413 | |
059ec3d9 | 414 | |
17c76198 PP |
415 | /************************************************* |
416 | * Set various Exim expansion vars * | |
417 | *************************************************/ | |
059ec3d9 | 418 | |
e51c7be2 JH |
419 | #define exim_gnutls_cert_err(Label) \ |
420 | do \ | |
421 | { \ | |
422 | if (rc != GNUTLS_E_SUCCESS) \ | |
423 | { \ | |
424 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
425 | (Label), gnutls_strerror(rc)); \ | |
426 | return rc; \ | |
427 | } \ | |
428 | } while (0) | |
9d1c15ef JH |
429 | |
430 | static int | |
27f19eb4 | 431 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
432 | { |
433 | int rc; | |
434 | ||
435 | rc = gnutls_x509_crt_init(crtp); | |
436 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
437 | ||
438 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
439 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
440 | ||
441 | return rc; | |
442 | } | |
443 | ||
444 | #undef exim_gnutls_cert_err | |
445 | ||
446 | ||
17c76198 PP |
447 | /* We set various Exim global variables from the state, once a session has |
448 | been established. With TLS callouts, may need to change this to stack | |
449 | variables, or just re-call it with the server state after client callout | |
450 | has finished. | |
059ec3d9 | 451 | |
9d1c15ef | 452 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
453 | |
454 | Sets: | |
455 | tls_active fd | |
456 | tls_bits strength indicator | |
457 | tls_certificate_verified bool indicator | |
458 | tls_channelbinding_b64 for some SASL mechanisms | |
459 | tls_cipher a string | |
9d1c15ef | 460 | tls_peercert pointer to library internal |
17c76198 PP |
461 | tls_peerdn a string |
462 | tls_sni a (UTF-8) string | |
9d1c15ef | 463 | tls_ourcert pointer to library internal |
17c76198 PP |
464 | |
465 | Argument: | |
466 | state the relevant exim_gnutls_state_st * | |
467 | */ | |
468 | ||
469 | static void | |
9d1c15ef | 470 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 471 | { |
17c76198 PP |
472 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
473 | int old_pool; | |
474 | int rc; | |
475 | gnutls_datum_t channel; | |
476 | #endif | |
9d1c15ef | 477 | tls_support * tlsp = state->tlsp; |
17c76198 | 478 | |
74f1a423 JH |
479 | tlsp->active.sock = state->fd_out; |
480 | tlsp->active.tls_ctx = state; | |
17c76198 | 481 | |
817d9f57 | 482 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 483 | |
9d1c15ef | 484 | tlsp->certificate_verified = state->peer_cert_verified; |
899b8bbc JH |
485 | #ifdef SUPPORT_DANE |
486 | tlsp->dane_verified = state->peer_dane_verified; | |
487 | #endif | |
059ec3d9 | 488 | |
17c76198 PP |
489 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
490 | only available for use for authenticators while this TLS session is running. */ | |
491 | ||
492 | tls_channelbinding_b64 = NULL; | |
493 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
494 | channel.data = NULL; | |
495 | channel.size = 0; | |
1f20760b JH |
496 | if ((rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel))) |
497 | { DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); } | |
498 | else | |
499 | { | |
17c76198 PP |
500 | old_pool = store_pool; |
501 | store_pool = POOL_PERM; | |
1f20760b | 502 | tls_channelbinding_b64 = b64encode(CUS channel.data, (int)channel.size); |
17c76198 PP |
503 | store_pool = old_pool; |
504 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
1f20760b | 505 | } |
17c76198 PP |
506 | #endif |
507 | ||
9d1c15ef JH |
508 | /* peercert is set in peer_status() */ |
509 | tlsp->peerdn = state->peerdn; | |
510 | tlsp->sni = state->received_sni; | |
511 | ||
512 | /* record our certificate */ | |
513 | { | |
27f19eb4 | 514 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
515 | gnutls_x509_crt_t crt; |
516 | ||
517 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
518 | } | |
059ec3d9 PH |
519 | } |
520 | ||
521 | ||
522 | ||
17c76198 | 523 | |
059ec3d9 | 524 | /************************************************* |
575643cd | 525 | * Setup up DH parameters * |
059ec3d9 PH |
526 | *************************************************/ |
527 | ||
575643cd | 528 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
529 | be re-generated every so often, depending on security policy. What we do is to |
530 | keep these parameters in a file in the spool directory. If the file does not | |
531 | exist, we generate them. This means that it is easy to cause a regeneration. | |
532 | ||
533 | The new file is written as a temporary file and renamed, so that an incomplete | |
534 | file is never present. If two processes both compute some new parameters, you | |
535 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
536 | prevent this. | |
537 | ||
059ec3d9 PH |
538 | Returns: OK/DEFER/FAIL |
539 | */ | |
540 | ||
541 | static int | |
cf0c6164 | 542 | init_server_dh(uschar ** errstr) |
059ec3d9 | 543 | { |
17c76198 PP |
544 | int fd, rc; |
545 | unsigned int dh_bits; | |
27f19eb4 | 546 | gnutls_datum_t m; |
a799883d PP |
547 | uschar filename_buf[PATH_MAX]; |
548 | uschar *filename = NULL; | |
17c76198 | 549 | size_t sz; |
a799883d PP |
550 | uschar *exp_tls_dhparam; |
551 | BOOL use_file_in_spool = FALSE; | |
17c76198 | 552 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 553 | |
17c76198 | 554 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 555 | |
452a164f JH |
556 | if ((rc = gnutls_dh_params_init(&dh_server_params))) |
557 | return tls_error_gnu(US"gnutls_dh_params_init", rc, host, errstr); | |
059ec3d9 | 558 | |
a799883d PP |
559 | m.data = NULL; |
560 | m.size = 0; | |
561 | ||
cf0c6164 | 562 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
563 | return DEFER; |
564 | ||
565 | if (!exp_tls_dhparam) | |
566 | { | |
567 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
568 | m.data = US std_dh_prime_default(); | |
569 | m.size = Ustrlen(m.data); | |
570 | } | |
571 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
572 | use_file_in_spool = TRUE; | |
573 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
574 | { | |
575 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
576 | return OK; | |
577 | } | |
578 | else if (exp_tls_dhparam[0] != '/') | |
579 | { | |
f5d25c2b | 580 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
48224640 | 581 | return tls_error(US"No standard prime named", exp_tls_dhparam, NULL, errstr); |
a799883d PP |
582 | m.size = Ustrlen(m.data); |
583 | } | |
584 | else | |
a799883d | 585 | filename = exp_tls_dhparam; |
a799883d PP |
586 | |
587 | if (m.data) | |
588 | { | |
452a164f JH |
589 | if ((rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM))) |
590 | return tls_error_gnu(US"gnutls_dh_params_import_pkcs3", rc, host, errstr); | |
a799883d PP |
591 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); |
592 | return OK; | |
593 | } | |
594 | ||
af3498d6 PP |
595 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
596 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 | 597 | different filename and ensure we have sufficient bits. */ |
452a164f JH |
598 | |
599 | if (!(dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL))) | |
cf0c6164 | 600 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 601 | DEBUG(D_tls) |
b34fc30c | 602 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
603 | dh_bits); |
604 | #else | |
605 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
606 | DEBUG(D_tls) | |
607 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
608 | dh_bits); | |
609 | #endif | |
059ec3d9 | 610 | |
3375e053 PP |
611 | /* Some clients have hard-coded limits. */ |
612 | if (dh_bits > tls_dh_max_bits) | |
613 | { | |
614 | DEBUG(D_tls) | |
615 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
616 | tls_dh_max_bits); | |
617 | dh_bits = tls_dh_max_bits; | |
618 | } | |
619 | ||
a799883d PP |
620 | if (use_file_in_spool) |
621 | { | |
622 | if (!string_format(filename_buf, sizeof(filename_buf), | |
623 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 624 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
625 | filename = filename_buf; |
626 | } | |
059ec3d9 | 627 | |
b5aea5e1 | 628 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 629 | parameters. */ |
059ec3d9 | 630 | |
f5d25c2b | 631 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 632 | { |
b5aea5e1 | 633 | struct stat statbuf; |
17c76198 PP |
634 | FILE *fp; |
635 | int saved_errno; | |
636 | ||
637 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
638 | { | |
639 | saved_errno = errno; | |
640 | (void)close(fd); | |
452a164f | 641 | return tls_error_sys(US"TLS cache stat failed", saved_errno, NULL, errstr); |
17c76198 PP |
642 | } |
643 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
644 | { |
645 | (void)close(fd); | |
cf0c6164 | 646 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 647 | } |
40c90bca | 648 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
649 | { |
650 | saved_errno = errno; | |
651 | (void)close(fd); | |
452a164f JH |
652 | return tls_error_sys(US"fdopen(TLS cache stat fd) failed", |
653 | saved_errno, NULL, errstr); | |
b5aea5e1 | 654 | } |
059ec3d9 | 655 | |
b5aea5e1 | 656 | m.size = statbuf.st_size; |
f3ebb786 | 657 | if (!(m.data = store_malloc(m.size))) |
17c76198 PP |
658 | { |
659 | fclose(fp); | |
452a164f | 660 | return tls_error_sys(US"malloc failed", errno, NULL, errstr); |
17c76198 | 661 | } |
40c90bca | 662 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
663 | { |
664 | saved_errno = errno; | |
665 | fclose(fp); | |
f3ebb786 | 666 | store_free(m.data); |
452a164f | 667 | return tls_error_sys(US"fread failed", saved_errno, NULL, errstr); |
17c76198 PP |
668 | } |
669 | fclose(fp); | |
b5aea5e1 | 670 | |
17c76198 | 671 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
f3ebb786 | 672 | store_free(m.data); |
452a164f JH |
673 | if (rc) |
674 | return tls_error_gnu(US"gnutls_dh_params_import_pkcs3", rc, host, errstr); | |
17c76198 | 675 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); |
b5aea5e1 PH |
676 | } |
677 | ||
678 | /* If the file does not exist, fall through to compute new data and cache it. | |
679 | If there was any other opening error, it is serious. */ | |
680 | ||
182ad5cf PH |
681 | else if (errno == ENOENT) |
682 | { | |
17c76198 | 683 | rc = -1; |
182ad5cf | 684 | DEBUG(D_tls) |
17c76198 | 685 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
686 | } |
687 | else | |
17c76198 | 688 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 689 | NULL, NULL, errstr); |
b5aea5e1 PH |
690 | |
691 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
692 | is not useful. One particular case of this is when upgrading from an older | |
693 | release of Exim in which the data was stored in a different format. We don't | |
694 | try to be clever and support both formats; we just regenerate new data in this | |
695 | case. */ | |
696 | ||
17c76198 | 697 | if (rc < 0) |
b5aea5e1 | 698 | { |
17c76198 | 699 | uschar *temp_fn; |
201f5254 | 700 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 701 | |
17c76198 PP |
702 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
703 | return tls_error(US"Filename too long to generate replacement", | |
48224640 | 704 | filename, NULL, errstr); |
059ec3d9 | 705 | |
48224640 | 706 | temp_fn = string_copy(US"%s.XXXXXXX"); |
f5d25c2b | 707 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
452a164f | 708 | return tls_error_sys(US"Unable to open temp file", errno, NULL, errstr); |
b66fecb4 | 709 | (void)exim_chown(temp_fn, exim_uid, exim_gid); /* Probably not necessary */ |
059ec3d9 | 710 | |
201f5254 PP |
711 | /* GnuTLS overshoots! |
712 | * If we ask for 2236, we might get 2237 or more. | |
713 | * But there's no way to ask GnuTLS how many bits there really are. | |
714 | * We can ask how many bits were used in a TLS session, but that's it! | |
715 | * The prime itself is hidden behind too much abstraction. | |
716 | * So we ask for less, and proceed on a wing and a prayer. | |
717 | * First attempt, subtracted 3 for 2233 and got 2240. | |
718 | */ | |
cae6e576 | 719 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
720 | { |
721 | dh_bits_gen = dh_bits - 10; | |
722 | DEBUG(D_tls) | |
723 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
724 | dh_bits_gen); | |
725 | } | |
726 | ||
727 | DEBUG(D_tls) | |
728 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
729 | dh_bits_gen); | |
452a164f JH |
730 | if ((rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen))) |
731 | return tls_error_gnu(US"gnutls_dh_params_generate2", rc, host, errstr); | |
17c76198 PP |
732 | |
733 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
734 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
735 | sample apps handle this. */ | |
736 | ||
737 | sz = 0; | |
738 | m.data = NULL; | |
452a164f JH |
739 | if ( (rc = gnutls_dh_params_export_pkcs3(dh_server_params, |
740 | GNUTLS_X509_FMT_PEM, m.data, &sz)) | |
741 | && rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
742 | return tls_error_gnu(US"gnutls_dh_params_export_pkcs3(NULL) sizing", | |
743 | rc, host, errstr); | |
17c76198 | 744 | m.size = sz; |
f3ebb786 | 745 | if (!(m.data = store_malloc(m.size))) |
452a164f | 746 | return tls_error_sys(US"memory allocation failed", errno, NULL, errstr); |
40c90bca | 747 | |
1f00591e | 748 | /* this will return a size 1 less than the allocation size above */ |
452a164f JH |
749 | if ((rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
750 | m.data, &sz))) | |
17c76198 | 751 | { |
f3ebb786 | 752 | store_free(m.data); |
452a164f | 753 | return tls_error_gnu(US"gnutls_dh_params_export_pkcs3() real", rc, host, errstr); |
17c76198 | 754 | } |
1f00591e | 755 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 756 | |
f5d25c2b | 757 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 | 758 | { |
f3ebb786 | 759 | store_free(m.data); |
452a164f JH |
760 | return tls_error_sys(US"TLS cache write D-H params failed", |
761 | errno, NULL, errstr); | |
17c76198 | 762 | } |
f3ebb786 | 763 | store_free(m.data); |
f5d25c2b | 764 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
452a164f JH |
765 | return tls_error_sys(US"TLS cache write D-H params final newline failed", |
766 | errno, NULL, errstr); | |
17c76198 | 767 | |
f5d25c2b | 768 | if ((rc = close(fd))) |
452a164f | 769 | return tls_error_sys(US"TLS cache write close() failed", errno, NULL, errstr); |
059ec3d9 | 770 | |
17c76198 | 771 | if (Urename(temp_fn, filename) < 0) |
452a164f JH |
772 | return tls_error_sys(string_sprintf("failed to rename \"%s\" as \"%s\"", |
773 | temp_fn, filename), errno, NULL, errstr); | |
059ec3d9 | 774 | |
17c76198 | 775 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
776 | } |
777 | ||
17c76198 | 778 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
779 | return OK; |
780 | } | |
781 | ||
782 | ||
783 | ||
784 | ||
23bb6982 JH |
785 | /* Create and install a selfsigned certificate, for use in server mode */ |
786 | ||
787 | static int | |
cf0c6164 | 788 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
789 | { |
790 | gnutls_x509_crt_t cert = NULL; | |
791 | time_t now; | |
792 | gnutls_x509_privkey_t pkey = NULL; | |
793 | const uschar * where; | |
794 | int rc; | |
795 | ||
796 | where = US"initialising pkey"; | |
797 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
798 | ||
799 | where = US"initialising cert"; | |
800 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
801 | ||
802 | where = US"generating pkey"; | |
803 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 804 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
4312da48 JH |
805 | # ifndef GNUTLS_SEC_PARAM_MEDIUM |
806 | # define GNUTLS_SEC_PARAM_MEDIUM GNUTLS_SEC_PARAM_HIGH | |
807 | # endif | |
6aac3239 | 808 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_MEDIUM), |
76075bb5 | 809 | #else |
6aac3239 | 810 | 2048, |
76075bb5 JH |
811 | #endif |
812 | 0))) | |
23bb6982 JH |
813 | goto err; |
814 | ||
815 | where = US"configuring cert"; | |
1613fd68 | 816 | now = 1; |
23bb6982 JH |
817 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) |
818 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
819 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
820 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
821 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
822 | ||
823 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
824 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
825 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
826 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
827 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
828 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
829 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
830 | ) | |
831 | goto err; | |
832 | ||
833 | where = US"signing cert"; | |
834 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
835 | ||
836 | where = US"installing selfsign cert"; | |
837 | /* Since: 2.4.0 */ | |
838 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
839 | goto err; | |
840 | ||
841 | rc = OK; | |
842 | ||
843 | out: | |
844 | if (cert) gnutls_x509_crt_deinit(cert); | |
845 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
846 | return rc; | |
847 | ||
848 | err: | |
452a164f | 849 | rc = tls_error_gnu(where, rc, NULL, errstr); |
23bb6982 JH |
850 | goto out; |
851 | } | |
852 | ||
853 | ||
854 | ||
855 | ||
47195144 JH |
856 | /* Add certificate and key, from files. |
857 | ||
858 | Return: | |
859 | Zero or negative: good. Negate value for certificate index if < 0. | |
860 | Greater than zero: FAIL or DEFER code. | |
861 | */ | |
862 | ||
ba86e143 JH |
863 | static int |
864 | tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, | |
865 | uschar * certfile, uschar * keyfile, uschar ** errstr) | |
866 | { | |
e5489333 JH |
867 | /*XXX returns certs index for gnutls_certificate_set_x509_key_file(), |
868 | given suitable flags set */ | |
869 | ||
ba86e143 JH |
870 | int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
871 | CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); | |
47195144 | 872 | if (rc < 0) |
452a164f | 873 | return tls_error_gnu( |
47195144 | 874 | string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile), |
452a164f | 875 | rc, host, errstr); |
47195144 | 876 | return -rc; |
ba86e143 JH |
877 | } |
878 | ||
879 | ||
e5489333 JH |
880 | /* Make a note that we saw a status-request */ |
881 | static int | |
882 | tls_server_clienthello_ext(void * ctx, unsigned tls_id, | |
883 | const unsigned char *data, unsigned size) | |
884 | { | |
885 | /* https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml */ | |
886 | if (tls_id == 5) /* status_request */ | |
887 | { | |
888 | DEBUG(D_tls) debug_printf("Seen status_request extension\n"); | |
889 | tls_in.ocsp = OCSP_NOT_RESP; | |
890 | } | |
891 | return 0; | |
892 | } | |
893 | ||
894 | /* Callback for client-hello, on server, if we think we might serve stapled-OCSP */ | |
895 | static int | |
896 | tls_server_clienthello_cb(gnutls_session_t session, unsigned int htype, | |
897 | unsigned when, unsigned int incoming, const gnutls_datum_t * msg) | |
898 | { | |
899 | /* Call fn for each extension seen. 3.6.3 onwards */ | |
900 | return gnutls_ext_raw_parse(NULL, tls_server_clienthello_ext, msg, | |
901 | GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO); | |
902 | } | |
903 | ||
904 | /* Callback for certificate-status, on server. We sent stapled OCSP. */ | |
905 | static int | |
906 | tls_server_certstatus_cb(gnutls_session_t session, unsigned int htype, | |
907 | unsigned when, unsigned int incoming, const gnutls_datum_t * msg) | |
908 | { | |
909 | DEBUG(D_tls) debug_printf("Sending certificate-status\n"); | |
910 | #ifdef SUPPORT_SRV_OCSP_STACK | |
911 | tls_in.ocsp = exim_testharness_disable_ocsp_validity_check | |
912 | ? OCSP_VFY_NOT_TRIED : OCSP_VFIED; /* We know that GnuTLS verifies responses */ | |
913 | #else | |
914 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; | |
915 | #endif | |
916 | return 0; | |
917 | } | |
918 | ||
919 | /* Callback for handshake messages, on server */ | |
920 | static int | |
921 | tls_server_hook_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
922 | unsigned incoming, const gnutls_datum_t * msg) | |
923 | { | |
924 | switch (htype) | |
925 | { | |
926 | case GNUTLS_HANDSHAKE_CLIENT_HELLO: | |
927 | return tls_server_clienthello_cb(sess, htype, when, incoming, msg); | |
928 | case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS: | |
929 | return tls_server_certstatus_cb(sess, htype, when, incoming, msg); | |
930 | #ifdef EXPERIMENTAL_TLS_RESUME | |
931 | case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET: | |
932 | return tls_server_ticket_cb(sess, htype, when, incoming, msg); | |
933 | #endif | |
934 | default: | |
935 | return 0; | |
936 | } | |
937 | } | |
938 | ||
939 | ||
940 | static void | |
941 | tls_server_testharness_ocsp_fiddle(void) | |
942 | { | |
943 | extern char ** environ; | |
944 | if (environ) for (uschar ** p = USS environ; *p; p++) | |
945 | if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) | |
946 | { | |
947 | DEBUG(D_tls) debug_printf("Permitting known bad OCSP response\n"); | |
948 | exim_testharness_disable_ocsp_validity_check = TRUE; | |
949 | } | |
950 | } | |
951 | ||
059ec3d9 | 952 | /************************************************* |
17c76198 | 953 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
954 | *************************************************/ |
955 | ||
17c76198 PP |
956 | /* Called from both server and client code, via tls_init(), and also from |
957 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
958 | ||
959 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
960 | ||
961 | The callback should not call us unless state->trigger_sni_changes is true, | |
962 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
963 | |
964 | Arguments: | |
17c76198 | 965 | state exim_gnutls_state_st * |
cf0c6164 | 966 | errstr error string pointer |
059ec3d9 PH |
967 | |
968 | Returns: OK/DEFER/FAIL | |
969 | */ | |
970 | ||
971 | static int | |
ba86e143 | 972 | tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 973 | { |
1365611d | 974 | struct stat statbuf; |
059ec3d9 | 975 | int rc; |
17c76198 PP |
976 | const host_item *host = state->host; /* macro should be reconsidered? */ |
977 | uschar *saved_tls_certificate = NULL; | |
978 | uschar *saved_tls_privatekey = NULL; | |
979 | uschar *saved_tls_verify_certificates = NULL; | |
980 | uschar *saved_tls_crl = NULL; | |
981 | int cert_count; | |
982 | ||
983 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 984 | if (!host) /* server */ |
17c76198 PP |
985 | if (!state->received_sni) |
986 | { | |
ba86e143 JH |
987 | if ( state->tls_certificate |
988 | && ( Ustrstr(state->tls_certificate, US"tls_sni") | |
989 | || Ustrstr(state->tls_certificate, US"tls_in_sni") | |
990 | || Ustrstr(state->tls_certificate, US"tls_out_sni") | |
991 | ) ) | |
17c76198 PP |
992 | { |
993 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
994 | state->trigger_sni_changes = TRUE; | |
995 | } | |
996 | } | |
997 | else | |
998 | { | |
1365611d | 999 | /* useful for debugging */ |
17c76198 PP |
1000 | saved_tls_certificate = state->exp_tls_certificate; |
1001 | saved_tls_privatekey = state->exp_tls_privatekey; | |
1002 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
1003 | saved_tls_crl = state->exp_tls_crl; | |
1004 | } | |
059ec3d9 | 1005 | |
452a164f JH |
1006 | if ((rc = gnutls_certificate_allocate_credentials(&state->x509_cred))) |
1007 | return tls_error_gnu(US"gnutls_certificate_allocate_credentials", | |
1008 | rc, host, errstr); | |
47195144 JH |
1009 | |
1010 | #ifdef SUPPORT_SRV_OCSP_STACK | |
1011 | gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2); | |
1012 | #endif | |
1365611d | 1013 | |
17c76198 PP |
1014 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
1015 | state members, assuming consistent naming; and expand_check() returns | |
1016 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 1017 | |
17c76198 PP |
1018 | /* check if we at least have a certificate, before doing expensive |
1019 | D-H generation. */ | |
059ec3d9 | 1020 | |
cf0c6164 | 1021 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 1022 | return DEFER; |
059ec3d9 | 1023 | |
17c76198 | 1024 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 1025 | |
23bb6982 JH |
1026 | if ( !state->exp_tls_certificate |
1027 | || !*state->exp_tls_certificate | |
1028 | ) | |
2b4a568d | 1029 | if (!host) |
cf0c6164 | 1030 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
1031 | else |
1032 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 1033 | |
cf0c6164 | 1034 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
1035 | return DEFER; |
1036 | ||
17c76198 PP |
1037 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
1038 | ||
1039 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 1040 | { |
17c76198 PP |
1041 | state->tls_privatekey = state->tls_certificate; |
1042 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 1043 | } |
c91535f3 | 1044 | |
059ec3d9 | 1045 | |
17c76198 | 1046 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
1047 | { |
1048 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
1049 | state->exp_tls_certificate, state->exp_tls_privatekey); |
1050 | ||
1051 | if (state->received_sni) | |
23bb6982 JH |
1052 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
1053 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
1054 | ) | |
17c76198 | 1055 | { |
b34fc30c | 1056 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
1057 | } |
1058 | else | |
1059 | { | |
b34fc30c | 1060 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 1061 | } |
059ec3d9 | 1062 | |
ba86e143 JH |
1063 | if (!host) /* server */ |
1064 | { | |
1065 | const uschar * clist = state->exp_tls_certificate; | |
1066 | const uschar * klist = state->exp_tls_privatekey; | |
47195144 JH |
1067 | const uschar * olist; |
1068 | int csep = 0, ksep = 0, osep = 0, cnt = 0; | |
1069 | uschar * cfile, * kfile, * ofile; | |
1070 | ||
1071 | #ifndef DISABLE_OCSP | |
1072 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr)) | |
1073 | return DEFER; | |
1074 | olist = ofile; | |
1075 | #endif | |
ba86e143 JH |
1076 | |
1077 | while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) | |
47195144 | 1078 | |
ba86e143 JH |
1079 | if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) |
1080 | return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); | |
47195144 | 1081 | else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr))) |
ba86e143 JH |
1082 | return rc; |
1083 | else | |
47195144 JH |
1084 | { |
1085 | int gnutls_cert_index = -rc; | |
e5489333 | 1086 | DEBUG(D_tls) debug_printf("TLS: cert/key %d %s registered\n", gnutls_cert_index, cfile); |
47195144 JH |
1087 | |
1088 | /* Set the OCSP stapling server info */ | |
1089 | ||
1090 | #ifndef DISABLE_OCSP | |
1091 | if (tls_ocsp_file) | |
e5489333 | 1092 | { |
47195144 JH |
1093 | if (gnutls_buggy_ocsp) |
1094 | { | |
1095 | DEBUG(D_tls) | |
1096 | debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
1097 | } | |
1098 | else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) | |
1099 | { | |
e5489333 | 1100 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); |
47195144 JH |
1101 | |
1102 | # ifdef SUPPORT_SRV_OCSP_STACK | |
e5489333 JH |
1103 | if (f.running_in_test_harness) tls_server_testharness_ocsp_fiddle(); |
1104 | ||
1105 | if (!exim_testharness_disable_ocsp_validity_check) | |
47195144 | 1106 | { |
e5489333 JH |
1107 | if ((rc = gnutls_certificate_set_ocsp_status_request_file2( |
1108 | state->x509_cred, CCS ofile, gnutls_cert_index, | |
1109 | GNUTLS_X509_FMT_DER)) < 0) | |
1110 | return tls_error_gnu( | |
1111 | US"gnutls_certificate_set_ocsp_status_request_file2", | |
1112 | rc, host, errstr); | |
1113 | ||
1114 | /* Arrange callbacks for OCSP request observability */ | |
1115 | ||
1116 | gnutls_handshake_set_hook_function(state->session, | |
1117 | GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb); | |
47195144 | 1118 | } |
e5489333 | 1119 | else |
47195144 | 1120 | # endif |
e5489333 JH |
1121 | { |
1122 | if (cnt++ > 0) | |
1123 | { | |
1124 | DEBUG(D_tls) | |
1125 | debug_printf("oops; multiple OCSP files not supported\n"); | |
1126 | break; | |
1127 | } | |
1128 | gnutls_certificate_set_ocsp_status_request_function( | |
1129 | state->x509_cred, server_ocsp_stapling_cb, ofile); | |
1130 | } | |
47195144 JH |
1131 | } |
1132 | else | |
1133 | DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); | |
1134 | #endif | |
e5489333 | 1135 | } |
47195144 | 1136 | } |
ba86e143 | 1137 | } |
e5489333 | 1138 | else /* client */ |
ba86e143 | 1139 | { |
47195144 | 1140 | if (0 < (rc = tls_add_certfile(state, host, |
ba86e143 JH |
1141 | state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) |
1142 | return rc; | |
1143 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
1144 | } | |
1145 | ||
b34fc30c | 1146 | } /* tls_certificate */ |
059ec3d9 | 1147 | |
2b4a568d | 1148 | |
059ec3d9 PH |
1149 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
1150 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
1151 | error message is provided. However, if we just refrain from setting anything up | |
1152 | in that case, certificate verification fails, which seems to be the correct | |
1153 | behaviour. */ | |
1154 | ||
610ff438 | 1155 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 1156 | { |
cf0c6164 | 1157 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 1158 | return DEFER; |
610ff438 JH |
1159 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
1160 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1161 | state->exp_tls_verify_certificates = NULL; | |
1162 | #endif | |
17c76198 | 1163 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 1164 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 1165 | return DEFER; |
059ec3d9 | 1166 | |
1365611d PP |
1167 | if (!(state->exp_tls_verify_certificates && |
1168 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
1169 | { |
1170 | DEBUG(D_tls) | |
1365611d PP |
1171 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
1172 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 1173 | return OK; |
b34fc30c | 1174 | } |
1365611d | 1175 | } |
83e2f8a2 PP |
1176 | else |
1177 | { | |
1178 | DEBUG(D_tls) | |
1179 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
1180 | return OK; | |
1181 | } | |
17c76198 | 1182 | |
cb1d7830 JH |
1183 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
1184 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1185 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
1186 | else | |
1187 | #endif | |
1365611d | 1188 | { |
cb1d7830 JH |
1189 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
1190 | { | |
1191 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
1192 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
1193 | strerror(errno)); | |
1194 | return DEFER; | |
1195 | } | |
17c76198 | 1196 | |
a7fec7a7 | 1197 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1198 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1199 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1200 | other weirdness. The thing we really want to check is that it's not a | |
1201 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1202 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1203 | if (S_ISDIR(statbuf.st_mode)) |
1204 | { | |
1205 | DEBUG(D_tls) | |
1206 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1207 | state->exp_tls_verify_certificates); | |
1208 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1209 | "tls_verify_certificates \"%s\" is a directory", | |
1210 | state->exp_tls_verify_certificates); | |
1211 | return DEFER; | |
1212 | } | |
a7fec7a7 | 1213 | #endif |
059ec3d9 | 1214 | |
cb1d7830 JH |
1215 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1216 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1217 | |
cb1d7830 JH |
1218 | if (statbuf.st_size == 0) |
1219 | { | |
1220 | DEBUG(D_tls) | |
1221 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1222 | return OK; | |
1223 | } | |
059ec3d9 | 1224 | |
cb1d7830 | 1225 | cert_count = |
a7fec7a7 JH |
1226 | |
1227 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1228 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1229 | ? | |
1230 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1231 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1232 | : | |
a7fec7a7 | 1233 | #endif |
cb1d7830 JH |
1234 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1235 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
12d95aa6 JH |
1236 | |
1237 | #ifdef SUPPORT_CA_DIR | |
1238 | /* Mimic the behaviour with OpenSSL of not advertising a usable-cert list | |
1239 | when using the directory-of-certs config model. */ | |
1240 | ||
1241 | if ((statbuf.st_mode & S_IFMT) == S_IFDIR) | |
1242 | gnutls_certificate_send_x509_rdn_sequence(state->session, 1); | |
1243 | #endif | |
cb1d7830 | 1244 | } |
a7fec7a7 | 1245 | |
1365611d | 1246 | if (cert_count < 0) |
452a164f JH |
1247 | return tls_error_gnu(US"setting certificate trust", cert_count, host, errstr); |
1248 | DEBUG(D_tls) | |
1249 | debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1250 | |
5c8cda3a PP |
1251 | if (state->tls_crl && *state->tls_crl && |
1252 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1253 | { |
5c8cda3a | 1254 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
452a164f JH |
1255 | if ((cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, |
1256 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM)) < 0) | |
1257 | return tls_error_gnu(US"gnutls_certificate_set_x509_crl_file", | |
1258 | cert_count, host, errstr); | |
1259 | ||
5c8cda3a | 1260 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1261 | } |
059ec3d9 | 1262 | |
059ec3d9 PH |
1263 | return OK; |
1264 | } | |
1265 | ||
1266 | ||
1267 | ||
1268 | ||
1365611d PP |
1269 | /************************************************* |
1270 | * Set X.509 state variables * | |
1271 | *************************************************/ | |
1272 | ||
1273 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1274 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1275 | structure. Which means various other non-re-expanded pieces of state | |
1276 | need to be re-set in the new struct, so the setting logic is pulled | |
1277 | out to this. | |
1278 | ||
1279 | Arguments: | |
1280 | state exim_gnutls_state_st * | |
cf0c6164 | 1281 | errstr error string pointer |
1365611d PP |
1282 | |
1283 | Returns: OK/DEFER/FAIL | |
1284 | */ | |
1285 | ||
1286 | static int | |
cf0c6164 | 1287 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1288 | { |
1289 | int rc; | |
1290 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1291 | ||
1292 | /* Create D-H parameters, or read them from the cache file. This function does | |
1293 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1294 | client-side params. */ | |
1295 | ||
1296 | if (!state->host) | |
1297 | { | |
1298 | if (!dh_server_params) | |
452a164f | 1299 | if ((rc = init_server_dh(errstr)) != OK) return rc; |
1365611d PP |
1300 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); |
1301 | } | |
1302 | ||
1303 | /* Link the credentials to the session. */ | |
1304 | ||
452a164f JH |
1305 | if ((rc = gnutls_credentials_set(state->session, |
1306 | GNUTLS_CRD_CERTIFICATE, state->x509_cred))) | |
1307 | return tls_error_gnu(US"gnutls_credentials_set", rc, host, errstr); | |
1365611d PP |
1308 | |
1309 | return OK; | |
1310 | } | |
1311 | ||
059ec3d9 | 1312 | /************************************************* |
17c76198 | 1313 | * Initialize for GnuTLS * |
059ec3d9 PH |
1314 | *************************************************/ |
1315 | ||
9196d5bf | 1316 | |
4fb7df6d JH |
1317 | #ifndef DISABLE_OCSP |
1318 | ||
9196d5bf JH |
1319 | static BOOL |
1320 | tls_is_buggy_ocsp(void) | |
1321 | { | |
1322 | const uschar * s; | |
1323 | uschar maj, mid, mic; | |
1324 | ||
1325 | s = CUS gnutls_check_version(NULL); | |
1326 | maj = atoi(CCS s); | |
1327 | if (maj == 3) | |
1328 | { | |
1329 | while (*s && *s != '.') s++; | |
1330 | mid = atoi(CCS ++s); | |
1331 | if (mid <= 2) | |
1332 | return TRUE; | |
1333 | else if (mid >= 5) | |
1334 | return FALSE; | |
1335 | else | |
1336 | { | |
1337 | while (*s && *s != '.') s++; | |
1338 | mic = atoi(CCS ++s); | |
1339 | return mic <= (mid == 3 ? 16 : 3); | |
1340 | } | |
1341 | } | |
1342 | return FALSE; | |
1343 | } | |
1344 | ||
4fb7df6d | 1345 | #endif |
9196d5bf JH |
1346 | |
1347 | ||
17c76198 PP |
1348 | /* Called from both server and client code. In the case of a server, errors |
1349 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1350 | |
1351 | Arguments: | |
17c76198 PP |
1352 | host connected host, if client; NULL if server |
1353 | certificate certificate file | |
1354 | privatekey private key file | |
1355 | sni TLS SNI to send, sometimes when client; else NULL | |
1356 | cas CA certs file | |
1357 | crl CRL file | |
1358 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1359 | caller_state returned state-info structure |
cf0c6164 | 1360 | errstr error string pointer |
059ec3d9 | 1361 | |
17c76198 | 1362 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1363 | */ |
1364 | ||
17c76198 PP |
1365 | static int |
1366 | tls_init( | |
1367 | const host_item *host, | |
1368 | const uschar *certificate, | |
1369 | const uschar *privatekey, | |
1370 | const uschar *sni, | |
1371 | const uschar *cas, | |
1372 | const uschar *crl, | |
1373 | const uschar *require_ciphers, | |
cf0c6164 | 1374 | exim_gnutls_state_st **caller_state, |
74f1a423 | 1375 | tls_support * tlsp, |
cf0c6164 | 1376 | uschar ** errstr) |
059ec3d9 | 1377 | { |
00c0dd4e | 1378 | exim_gnutls_state_st * state; |
17c76198 PP |
1379 | int rc; |
1380 | size_t sz; | |
00c0dd4e JH |
1381 | const char * errpos; |
1382 | const uschar * p; | |
17c76198 PP |
1383 | |
1384 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1385 | { |
17c76198 PP |
1386 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1387 | ||
a5f239e4 PP |
1388 | #ifdef HAVE_GNUTLS_PKCS11 |
1389 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1390 | which loads modules from a config file, which sounds good and may be wanted | |
1391 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1392 | environment variables are used and so breaks for users calling mailq. | |
1393 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1394 | if (!gnutls_allow_auto_pkcs11) |
452a164f JH |
1395 | if ((rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL))) |
1396 | return tls_error_gnu(US"gnutls_pkcs11_init", rc, host, errstr); | |
a5f239e4 PP |
1397 | #endif |
1398 | ||
452a164f JH |
1399 | if ((rc = gnutls_global_init())) |
1400 | return tls_error_gnu(US"gnutls_global_init", rc, host, errstr); | |
17c76198 PP |
1401 | |
1402 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1403 | DEBUG(D_tls) | |
059ec3d9 | 1404 | { |
17c76198 | 1405 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
aded2255 | 1406 | /* arbitrarily chosen level; bump up to 9 for more */ |
17c76198 | 1407 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); |
059ec3d9 | 1408 | } |
17c76198 PP |
1409 | #endif |
1410 | ||
4fb7df6d JH |
1411 | #ifndef DISABLE_OCSP |
1412 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1413 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1414 | #endif |
9196d5bf | 1415 | |
17c76198 | 1416 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1417 | } |
059ec3d9 | 1418 | |
17c76198 PP |
1419 | if (host) |
1420 | { | |
74f1a423 JH |
1421 | /* For client-side sessions we allocate a context. This lets us run |
1422 | several in parallel. */ | |
1423 | int old_pool = store_pool; | |
1424 | store_pool = POOL_PERM; | |
f3ebb786 | 1425 | state = store_get(sizeof(exim_gnutls_state_st), FALSE); |
74f1a423 JH |
1426 | store_pool = old_pool; |
1427 | ||
17c76198 | 1428 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
74f1a423 | 1429 | state->tlsp = tlsp; |
17c76198 PP |
1430 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1431 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1432 | } | |
1433 | else | |
1434 | { | |
1435 | state = &state_server; | |
1436 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
74f1a423 | 1437 | state->tlsp = tlsp; |
17c76198 PP |
1438 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1439 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1440 | } | |
452a164f JH |
1441 | if (rc) |
1442 | return tls_error_gnu(US"gnutls_init", rc, host, errstr); | |
059ec3d9 | 1443 | |
17c76198 | 1444 | state->host = host; |
059ec3d9 | 1445 | |
17c76198 PP |
1446 | state->tls_certificate = certificate; |
1447 | state->tls_privatekey = privatekey; | |
5779e6aa | 1448 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1449 | state->tls_sni = sni; |
1450 | state->tls_verify_certificates = cas; | |
1451 | state->tls_crl = crl; | |
059ec3d9 | 1452 | |
17c76198 PP |
1453 | /* This handles the variables that might get re-expanded after TLS SNI; |
1454 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1455 | |
17c76198 PP |
1456 | DEBUG(D_tls) |
1457 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1458 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1459 | |
1365611d PP |
1460 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1461 | requires a new structure afterwards. */ | |
83da1223 | 1462 | |
cf0c6164 | 1463 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1464 | |
17c76198 PP |
1465 | /* set SNI in client, only */ |
1466 | if (host) | |
1467 | { | |
cf0c6164 | 1468 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1469 | return DEFER; |
0df4ab80 | 1470 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1471 | { |
1472 | DEBUG(D_tls) | |
0df4ab80 JH |
1473 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1474 | sz = Ustrlen(state->tlsp->sni); | |
452a164f JH |
1475 | if ((rc = gnutls_server_name_set(state->session, |
1476 | GNUTLS_NAME_DNS, state->tlsp->sni, sz))) | |
1477 | return tls_error_gnu(US"gnutls_server_name_set", rc, host, errstr); | |
17c76198 PP |
1478 | } |
1479 | } | |
1480 | else if (state->tls_sni) | |
1481 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
ba86e143 | 1482 | "have an SNI set for a server [%s]\n", state->tls_sni); |
83da1223 | 1483 | |
17c76198 | 1484 | /* This is the priority string support, |
42bfef1e | 1485 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1486 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1487 | This was backwards incompatible, but means Exim no longer needs to track | |
1488 | all algorithms and provide string forms for them. */ | |
83da1223 | 1489 | |
fc243e94 | 1490 | p = NULL; |
17c76198 | 1491 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1492 | { |
cf0c6164 | 1493 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1494 | return DEFER; |
1495 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1496 | { |
17c76198 | 1497 | p = state->exp_tls_require_ciphers; |
fc243e94 | 1498 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", p); |
83da1223 PH |
1499 | } |
1500 | } | |
fc243e94 | 1501 | if (!p) |
17c76198 | 1502 | { |
fc243e94 | 1503 | p = exim_default_gnutls_priority; |
83e2f8a2 | 1504 | DEBUG(D_tls) |
fc243e94 | 1505 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", p); |
17c76198 | 1506 | } |
83da1223 | 1507 | |
452a164f JH |
1508 | if ((rc = gnutls_priority_init(&state->priority_cache, CCS p, &errpos))) |
1509 | return tls_error_gnu(string_sprintf( | |
1510 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1511 | p, errpos - CS p, errpos), | |
1512 | rc, host, errstr); | |
17c76198 | 1513 | |
452a164f JH |
1514 | if ((rc = gnutls_priority_set(state->session, state->priority_cache))) |
1515 | return tls_error_gnu(US"gnutls_priority_set", rc, host, errstr); | |
17c76198 | 1516 | |
b10c87b3 JH |
1517 | /* This also sets the server ticket expiration time to the same, and |
1518 | the STEK rotation time to 3x. */ | |
1519 | ||
17c76198 PP |
1520 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); |
1521 | ||
1522 | /* Reduce security in favour of increased compatibility, if the admin | |
1523 | decides to make that trade-off. */ | |
1524 | if (gnutls_compat_mode) | |
83da1223 | 1525 | { |
17c76198 PP |
1526 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1527 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1528 | gnutls_session_enable_compatibility_mode(state->session); | |
1529 | #else | |
1530 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1531 | #endif | |
83da1223 PH |
1532 | } |
1533 | ||
17c76198 | 1534 | *caller_state = state; |
17c76198 | 1535 | return OK; |
83da1223 PH |
1536 | } |
1537 | ||
1538 | ||
1539 | ||
059ec3d9 | 1540 | /************************************************* |
17c76198 | 1541 | * Extract peer information * |
059ec3d9 PH |
1542 | *************************************************/ |
1543 | ||
f1be21cf JH |
1544 | static const uschar * |
1545 | cipher_stdname_kcm(gnutls_kx_algorithm_t kx, gnutls_cipher_algorithm_t cipher, | |
1546 | gnutls_mac_algorithm_t mac) | |
1547 | { | |
1548 | uschar cs_id[2]; | |
1549 | gnutls_kx_algorithm_t kx_i; | |
1550 | gnutls_cipher_algorithm_t cipher_i; | |
1551 | gnutls_mac_algorithm_t mac_i; | |
1552 | ||
1553 | for (size_t i = 0; | |
1554 | gnutls_cipher_suite_info(i, cs_id, &kx_i, &cipher_i, &mac_i, NULL); | |
1555 | i++) | |
1556 | if (kx_i == kx && cipher_i == cipher && mac_i == mac) | |
1557 | return cipher_stdname(cs_id[0], cs_id[1]); | |
1558 | return NULL; | |
1559 | } | |
1560 | ||
1561 | ||
1562 | ||
17c76198 | 1563 | /* Called from both server and client code. |
4fe99a6c PP |
1564 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1565 | and we use that to detect double-calls. | |
059ec3d9 | 1566 | |
75fe387d PP |
1567 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1568 | for logging in the server side, but for the client side, we log after teardown | |
1569 | in src/deliver.c. While the session is up, we can twist about states and | |
1570 | repoint tls_* globals, but those variables used for logging or other variable | |
1571 | expansion that happens _after_ delivery need to have a longer life-time. | |
1572 | ||
1573 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1574 | doing this more than once per generation of a state context. We set them in | |
1575 | the state context, and repoint tls_* to them. After the state goes away, the | |
1576 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1577 | ||
1578 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1579 | don't apply. | |
1580 | ||
059ec3d9 | 1581 | Arguments: |
17c76198 | 1582 | state exim_gnutls_state_st * |
cf0c6164 | 1583 | errstr pointer to error string |
059ec3d9 | 1584 | |
17c76198 | 1585 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1586 | */ |
1587 | ||
17c76198 | 1588 | static int |
b10c87b3 | 1589 | peer_status(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 1590 | { |
b10c87b3 JH |
1591 | gnutls_session_t session = state->session; |
1592 | const gnutls_datum_t * cert_list; | |
75fe387d | 1593 | int old_pool, rc; |
17c76198 | 1594 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1595 | gnutls_protocol_t protocol; |
1596 | gnutls_cipher_algorithm_t cipher; | |
1597 | gnutls_kx_algorithm_t kx; | |
1598 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1599 | gnutls_certificate_type_t ct; |
1600 | gnutls_x509_crt_t crt; | |
b10c87b3 | 1601 | uschar * dn_buf; |
17c76198 | 1602 | size_t sz; |
059ec3d9 | 1603 | |
4fe99a6c | 1604 | if (state->have_set_peerdn) |
17c76198 | 1605 | return OK; |
4fe99a6c | 1606 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1607 | |
4fe99a6c | 1608 | state->peerdn = NULL; |
059ec3d9 | 1609 | |
4fe99a6c | 1610 | /* tls_cipher */ |
b10c87b3 JH |
1611 | cipher = gnutls_cipher_get(session); |
1612 | protocol = gnutls_protocol_get_version(session); | |
1613 | mac = gnutls_mac_get(session); | |
b9c6f63c JH |
1614 | kx = |
1615 | #ifdef GNUTLS_TLS1_3 | |
1616 | protocol >= GNUTLS_TLS1_3 ? 0 : | |
1617 | #endif | |
b10c87b3 | 1618 | gnutls_kx_get(session); |
4fe99a6c | 1619 | |
75fe387d | 1620 | old_pool = store_pool; |
f1be21cf | 1621 | { |
b10c87b3 | 1622 | tls_support * tlsp = state->tlsp; |
f1be21cf | 1623 | store_pool = POOL_PERM; |
d9acfc1c JH |
1624 | |
1625 | #ifdef SUPPORT_GNUTLS_SESS_DESC | |
1626 | { | |
1627 | gstring * g = NULL; | |
b10c87b3 | 1628 | uschar * s = US gnutls_session_get_desc(session), c; |
d9acfc1c JH |
1629 | |
1630 | /* Nikos M suggests we use this by preference. It returns like: | |
1631 | (TLS1.3)-(ECDHE-SECP256R1)-(RSA-PSS-RSAE-SHA256)-(AES-256-GCM) | |
1632 | ||
1633 | For partial back-compat, put a colon after the TLS version, replace the | |
1634 | )-( grouping with __, replace in-group - with _ and append the :keysize. */ | |
1635 | ||
1636 | /* debug_printf("peer_status: gnutls_session_get_desc %s\n", s); */ | |
1637 | ||
1638 | for (s++; (c = *s) && c != ')'; s++) g = string_catn(g, s, 1); | |
1639 | g = string_catn(g, US":", 1); | |
1640 | if (*s) s++; /* now on _ between groups */ | |
1641 | while ((c = *s)) | |
1642 | { | |
1643 | for (*++s && ++s; (c = *s) && c != ')'; s++) g = string_catn(g, c == '-' ? US"_" : s, 1); | |
1644 | /* now on ) closing group */ | |
1645 | if ((c = *s) && *++s == '-') g = string_catn(g, US"__", 2); | |
1646 | /* now on _ between groups */ | |
1647 | } | |
1648 | g = string_catn(g, US":", 1); | |
1649 | g = string_cat(g, string_sprintf("%d", (int) gnutls_cipher_get_key_size(cipher) * 8)); | |
1650 | state->ciphersuite = string_from_gstring(g); | |
1651 | } | |
1652 | #else | |
f1be21cf JH |
1653 | state->ciphersuite = string_sprintf("%s:%s:%d", |
1654 | gnutls_protocol_get_name(protocol), | |
1655 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1656 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1657 | ||
1658 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1659 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1660 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
1661 | ||
1662 | for (uschar * p = state->ciphersuite; *p; p++) if (isspace(*p)) *p = '-'; | |
d9acfc1c JH |
1663 | #endif |
1664 | ||
1665 | /* debug_printf("peer_status: ciphersuite %s\n", state->ciphersuite); */ | |
1666 | ||
b10c87b3 JH |
1667 | tlsp->cipher = state->ciphersuite; |
1668 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; | |
f1be21cf | 1669 | |
b10c87b3 | 1670 | tlsp->cipher_stdname = cipher_stdname_kcm(kx, cipher, mac); |
f1be21cf | 1671 | } |
75fe387d | 1672 | store_pool = old_pool; |
4fe99a6c PP |
1673 | |
1674 | /* tls_peerdn */ | |
b10c87b3 | 1675 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); |
83da1223 | 1676 | |
f1be21cf | 1677 | if (!cert_list || cert_list_size == 0) |
17c76198 | 1678 | { |
17c76198 PP |
1679 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1680 | cert_list, cert_list_size); | |
e51c7be2 | 1681 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1682 | return tls_error(US"certificate verification failed", |
48224640 | 1683 | US"no certificate received from peer", state->host, errstr); |
17c76198 PP |
1684 | return OK; |
1685 | } | |
059ec3d9 | 1686 | |
b10c87b3 | 1687 | if ((ct = gnutls_certificate_type_get(session)) != GNUTLS_CRT_X509) |
059ec3d9 | 1688 | { |
95f52235 | 1689 | const uschar * ctn = US gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1690 | DEBUG(D_tls) |
1691 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1692 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1693 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1694 | ctn, state->host, errstr); |
17c76198 | 1695 | return OK; |
83da1223 | 1696 | } |
059ec3d9 | 1697 | |
e51c7be2 JH |
1698 | #define exim_gnutls_peer_err(Label) \ |
1699 | do { \ | |
1700 | if (rc != GNUTLS_E_SUCCESS) \ | |
1701 | { \ | |
1702 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1703 | (Label), gnutls_strerror(rc)); \ | |
1704 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
452a164f | 1705 | return tls_error_gnu((Label), rc, state->host, errstr); \ |
e51c7be2 JH |
1706 | return OK; \ |
1707 | } \ | |
1708 | } while (0) | |
17c76198 | 1709 | |
9d1c15ef JH |
1710 | rc = import_cert(&cert_list[0], &crt); |
1711 | exim_gnutls_peer_err(US"cert 0"); | |
1712 | ||
1713 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1714 | |
17c76198 PP |
1715 | sz = 0; |
1716 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1717 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1718 | { |
17c76198 PP |
1719 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1720 | return FAIL; /* should not happen */ | |
059ec3d9 | 1721 | } |
f3ebb786 | 1722 | dn_buf = store_get_perm(sz, TRUE); /* tainted */ |
17c76198 PP |
1723 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); |
1724 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1725 | |
17c76198 PP |
1726 | state->peerdn = dn_buf; |
1727 | ||
1728 | return OK; | |
1729 | #undef exim_gnutls_peer_err | |
1730 | } | |
059ec3d9 | 1731 | |
059ec3d9 | 1732 | |
059ec3d9 | 1733 | |
059ec3d9 | 1734 | |
17c76198 PP |
1735 | /************************************************* |
1736 | * Verify peer certificate * | |
1737 | *************************************************/ | |
059ec3d9 | 1738 | |
17c76198 PP |
1739 | /* Called from both server and client code. |
1740 | *Should* be using a callback registered with | |
1741 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1742 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1743 | |
17c76198 | 1744 | Arguments: |
899b8bbc JH |
1745 | state exim_gnutls_state_st * |
1746 | errstr where to put an error message | |
059ec3d9 | 1747 | |
17c76198 PP |
1748 | Returns: |
1749 | FALSE if the session should be rejected | |
1750 | TRUE if the cert is okay or we just don't care | |
1751 | */ | |
059ec3d9 | 1752 | |
17c76198 | 1753 | static BOOL |
28646fa9 | 1754 | verify_certificate(exim_gnutls_state_st * state, uschar ** errstr) |
17c76198 PP |
1755 | { |
1756 | int rc; | |
899b8bbc JH |
1757 | uint verify; |
1758 | ||
8008accd | 1759 | DEBUG(D_tls) debug_printf("TLS: checking peer certificate\n"); |
cf0c6164 | 1760 | *errstr = NULL; |
b10c87b3 | 1761 | rc = peer_status(state, errstr); |
17c76198 | 1762 | |
b10c87b3 JH |
1763 | if (state->verify_requirement == VERIFY_NONE) |
1764 | return TRUE; | |
1765 | ||
1766 | if (rc != OK || !state->peerdn) | |
e6060e2c | 1767 | { |
17c76198 | 1768 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1769 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1770 | } |
1771 | else | |
899b8bbc JH |
1772 | |
1773 | { | |
1774 | #ifdef SUPPORT_DANE | |
1775 | if (state->verify_requirement == VERIFY_DANE && state->host) | |
1776 | { | |
1777 | /* Using dane_verify_session_crt() would be easy, as it does it all for us | |
1778 | including talking to a DNS resolver. But we want to do that bit ourselves | |
1779 | as the testsuite intercepts and fakes its own DNS environment. */ | |
1780 | ||
1781 | dane_state_t s; | |
1782 | dane_query_t r; | |
899b8bbc | 1783 | uint lsize; |
94c13285 JH |
1784 | const gnutls_datum_t * certlist = |
1785 | gnutls_certificate_get_peers(state->session, &lsize); | |
1786 | int usage = tls_out.tlsa_usage; | |
1787 | ||
1788 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION | |
1789 | /* Split the TLSA records into two sets, TA and EE selectors. Run the | |
1790 | dane-verification separately so that we know which selector verified; | |
570cb1bd | 1791 | then we know whether to do name-verification (needed for TA but not EE). */ |
94c13285 JH |
1792 | |
1793 | if (usage == ((1<<DANESSL_USAGE_DANE_TA) | (1<<DANESSL_USAGE_DANE_EE))) | |
bd5b3f3c | 1794 | { /* a mixed-usage bundle */ |
94c13285 JH |
1795 | int i, j, nrec; |
1796 | const char ** dd; | |
1797 | int * ddl; | |
1798 | ||
1799 | for(nrec = 0; state->dane_data_len[nrec]; ) nrec++; | |
1800 | nrec++; | |
1801 | ||
f3ebb786 JH |
1802 | dd = store_get(nrec * sizeof(uschar *), FALSE); |
1803 | ddl = store_get(nrec * sizeof(int), FALSE); | |
94c13285 JH |
1804 | nrec--; |
1805 | ||
1806 | if ((rc = dane_state_init(&s, 0))) | |
1807 | goto tlsa_prob; | |
1808 | ||
1809 | for (usage = DANESSL_USAGE_DANE_EE; | |
1810 | usage >= DANESSL_USAGE_DANE_TA; usage--) | |
1811 | { /* take records with this usage */ | |
1812 | for (j = i = 0; i < nrec; i++) | |
1813 | if (state->dane_data[i][0] == usage) | |
1814 | { | |
1815 | dd[j] = state->dane_data[i]; | |
1816 | ddl[j++] = state->dane_data_len[i]; | |
1817 | } | |
1818 | if (j) | |
1819 | { | |
1820 | dd[j] = NULL; | |
1821 | ddl[j] = 0; | |
1822 | ||
1823 | if ((rc = dane_raw_tlsa(s, &r, (char * const *)dd, ddl, 1, 0))) | |
1824 | goto tlsa_prob; | |
1825 | ||
1826 | if ((rc = dane_verify_crt_raw(s, certlist, lsize, | |
1827 | gnutls_certificate_type_get(state->session), | |
1828 | r, 0, | |
1829 | usage == DANESSL_USAGE_DANE_EE | |
1830 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1831 | &verify))) | |
1832 | { | |
1833 | DEBUG(D_tls) | |
1834 | debug_printf("TLSA record problem: %s\n", dane_strerror(rc)); | |
1835 | } | |
1836 | else if (verify == 0) /* verification passed */ | |
1837 | { | |
1838 | usage = 1 << usage; | |
1839 | break; | |
1840 | } | |
1841 | } | |
1842 | } | |
899b8bbc | 1843 | |
94c13285 JH |
1844 | if (rc) goto tlsa_prob; |
1845 | } | |
1846 | else | |
1847 | # endif | |
899b8bbc | 1848 | { |
94c13285 JH |
1849 | if ( (rc = dane_state_init(&s, 0)) |
1850 | || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len, | |
1851 | 1, 0)) | |
1852 | || (rc = dane_verify_crt_raw(s, certlist, lsize, | |
1853 | gnutls_certificate_type_get(state->session), | |
5ec37a55 | 1854 | r, 0, |
94c13285 JH |
1855 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1856 | usage == (1 << DANESSL_USAGE_DANE_EE) | |
1857 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1858 | # else | |
1859 | 0, | |
1860 | # endif | |
1861 | &verify)) | |
1862 | ) | |
1863 | goto tlsa_prob; | |
899b8bbc | 1864 | } |
94c13285 JH |
1865 | |
1866 | if (verify != 0) /* verification failed */ | |
899b8bbc JH |
1867 | { |
1868 | gnutls_datum_t str; | |
1869 | (void) dane_verification_status_print(verify, &str, 0); | |
1870 | *errstr = US str.data; /* don't bother to free */ | |
1871 | goto badcert; | |
1872 | } | |
28646fa9 | 1873 | |
94c13285 JH |
1874 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1875 | /* If a TA-mode TLSA record was used for verification we must additionally | |
570cb1bd | 1876 | verify the cert name (but not the CA chain). For EE-mode, skip it. */ |
28646fa9 | 1877 | |
94c13285 JH |
1878 | if (usage & (1 << DANESSL_USAGE_DANE_EE)) |
1879 | # endif | |
28646fa9 | 1880 | { |
570cb1bd | 1881 | state->peer_dane_verified = state->peer_cert_verified = TRUE; |
28646fa9 JH |
1882 | goto goodcert; |
1883 | } | |
570cb1bd JH |
1884 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1885 | /* Assume that the name on the A-record is the one that should be matching | |
1886 | the cert. An alternate view is that the domain part of the email address | |
1887 | is also permissible. */ | |
1888 | ||
1889 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, | |
1890 | CS state->host->name)) | |
1891 | { | |
1892 | state->peer_dane_verified = state->peer_cert_verified = TRUE; | |
1893 | goto goodcert; | |
1894 | } | |
1895 | # endif | |
899b8bbc | 1896 | } |
570cb1bd | 1897 | #endif /*SUPPORT_DANE*/ |
899b8bbc | 1898 | |
17c76198 | 1899 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
899b8bbc | 1900 | } |
e6060e2c | 1901 | |
899b8bbc | 1902 | /* Handle the result of verification. INVALID is set if any others are. */ |
059ec3d9 | 1903 | |
28646fa9 | 1904 | if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) |
17c76198 PP |
1905 | { |
1906 | state->peer_cert_verified = FALSE; | |
cf0c6164 | 1907 | if (!*errstr) |
184384c3 JH |
1908 | { |
1909 | #ifdef GNUTLS_CERT_VFY_STATUS_PRINT | |
1910 | DEBUG(D_tls) | |
1911 | { | |
1912 | gnutls_datum_t txt; | |
1913 | ||
1914 | if (gnutls_certificate_verification_status_print(verify, | |
1915 | gnutls_certificate_type_get(state->session), &txt, 0) | |
1916 | == GNUTLS_E_SUCCESS) | |
1917 | { | |
1918 | debug_printf("%s\n", txt.data); | |
1919 | gnutls_free(txt.data); | |
1920 | } | |
1921 | } | |
1922 | #endif | |
cf0c6164 JH |
1923 | *errstr = verify & GNUTLS_CERT_REVOKED |
1924 | ? US"certificate revoked" : US"certificate invalid"; | |
184384c3 | 1925 | } |
059ec3d9 | 1926 | |
17c76198 | 1927 | DEBUG(D_tls) |
e51c7be2 | 1928 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1929 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1930 | |
e51c7be2 | 1931 | if (state->verify_requirement >= VERIFY_REQUIRED) |
899b8bbc | 1932 | goto badcert; |
17c76198 | 1933 | DEBUG(D_tls) |
4789da3a | 1934 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1935 | } |
e51c7be2 | 1936 | |
17c76198 PP |
1937 | else |
1938 | { | |
5fd28bb8 JH |
1939 | /* Client side, check the server's certificate name versus the name on the |
1940 | A-record for the connection we made. What to do for server side - what name | |
1941 | to use for client? We document that there is no such checking for server | |
1942 | side. */ | |
1943 | ||
1944 | if ( state->exp_tls_verify_cert_hostnames | |
1945 | && !gnutls_x509_crt_check_hostname(state->tlsp->peercert, | |
1946 | CS state->exp_tls_verify_cert_hostnames) | |
1947 | ) | |
e51c7be2 | 1948 | { |
5fd28bb8 JH |
1949 | DEBUG(D_tls) |
1950 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
1951 | if (state->verify_requirement >= VERIFY_REQUIRED) | |
1952 | goto badcert; | |
1953 | return TRUE; | |
e51c7be2 | 1954 | } |
5fd28bb8 | 1955 | |
17c76198 | 1956 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1957 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1958 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1959 | } |
059ec3d9 | 1960 | |
28646fa9 JH |
1961 | goodcert: |
1962 | state->tlsp->peerdn = state->peerdn; | |
1963 | return TRUE; | |
899b8bbc | 1964 | |
b83314e3 | 1965 | #ifdef SUPPORT_DANE |
94c13285 | 1966 | tlsa_prob: |
624f33df JH |
1967 | *errstr = string_sprintf("TLSA record problem: %s", |
1968 | rc == DANE_E_REQUESTED_DATA_NOT_AVAILABLE ? "none usable" : dane_strerror(rc)); | |
b83314e3 JH |
1969 | #endif |
1970 | ||
899b8bbc JH |
1971 | badcert: |
1972 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1973 | return FALSE; | |
17c76198 | 1974 | } |
059ec3d9 | 1975 | |
17c76198 PP |
1976 | |
1977 | ||
1978 | ||
1979 | /* ------------------------------------------------------------------------ */ | |
1980 | /* Callbacks */ | |
1981 | ||
1982 | /* Logging function which can be registered with | |
1983 | * gnutls_global_set_log_function() | |
1984 | * gnutls_global_set_log_level() 0..9 | |
1985 | */ | |
af3498d6 | 1986 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1987 | static void |
17c76198 | 1988 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1989 | { |
8c79eebf PP |
1990 | size_t len = strlen(message); |
1991 | if (len < 1) | |
1992 | { | |
1993 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1994 | return; | |
1995 | } | |
1996 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1997 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1998 | } |
af3498d6 | 1999 | #endif |
059ec3d9 | 2000 | |
059ec3d9 | 2001 | |
17c76198 PP |
2002 | /* Called after client hello, should handle SNI work. |
2003 | This will always set tls_sni (state->received_sni) if available, | |
2004 | and may trigger presenting different certificates, | |
2005 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 2006 | |
17c76198 PP |
2007 | Should be registered with |
2008 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 2009 | |
17c76198 PP |
2010 | "This callback must return 0 on success or a gnutls error code to terminate the |
2011 | handshake.". | |
059ec3d9 | 2012 | |
17c76198 PP |
2013 | For inability to get SNI information, we return 0. |
2014 | We only return non-zero if re-setup failed. | |
817d9f57 | 2015 | Only used for server-side TLS. |
17c76198 | 2016 | */ |
44bbabb5 | 2017 | |
17c76198 PP |
2018 | static int |
2019 | exim_sni_handling_cb(gnutls_session_t session) | |
2020 | { | |
2021 | char sni_name[MAX_HOST_LEN]; | |
2022 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 2023 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
2024 | unsigned int sni_type; |
2025 | int rc, old_pool; | |
cf0c6164 | 2026 | uschar * dummy_errstr; |
17c76198 PP |
2027 | |
2028 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
2029 | if (rc != GNUTLS_E_SUCCESS) |
2030 | { | |
8775d84f | 2031 | DEBUG(D_tls) |
b34fc30c PP |
2032 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) |
2033 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
2034 | else | |
2035 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
2036 | gnutls_strerror(rc), rc); | |
b34fc30c PP |
2037 | return 0; |
2038 | } | |
2039 | ||
17c76198 PP |
2040 | if (sni_type != GNUTLS_NAME_DNS) |
2041 | { | |
2042 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
2043 | return 0; | |
2044 | } | |
44bbabb5 | 2045 | |
17c76198 PP |
2046 | /* We now have a UTF-8 string in sni_name */ |
2047 | old_pool = store_pool; | |
2048 | store_pool = POOL_PERM; | |
89a80675 | 2049 | state->received_sni = string_copy_taint(US sni_name, TRUE); |
17c76198 PP |
2050 | store_pool = old_pool; |
2051 | ||
2052 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 2053 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
2054 | |
2055 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
2056 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
2057 | ||
2058 | if (!state->trigger_sni_changes) | |
2059 | return 0; | |
2060 | ||
cf0c6164 | 2061 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
2062 | { |
2063 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
2064 | been offered. The best we can do now is abort. */ | |
2065 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
2066 | } | |
2067 | ||
cf0c6164 | 2068 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
2069 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
2070 | ||
2071 | return 0; | |
059ec3d9 PH |
2072 | } |
2073 | ||
2074 | ||
2075 | ||
e5489333 | 2076 | #if !defined(DISABLE_OCSP) |
44662487 JH |
2077 | |
2078 | static int | |
2079 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
2080 | gnutls_datum_t * ocsp_response) | |
2081 | { | |
2082 | int ret; | |
47195144 | 2083 | DEBUG(D_tls) debug_printf("OCSP stapling callback: %s\n", US ptr); |
44662487 | 2084 | |
44662487 JH |
2085 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
2086 | { | |
2087 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
5903c6ff | 2088 | CS ptr); |
018058b2 | 2089 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
2090 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
2091 | } | |
2092 | ||
018058b2 | 2093 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
2094 | return 0; |
2095 | } | |
2096 | ||
2097 | #endif | |
2098 | ||
2099 | ||
0cbf2b82 | 2100 | #ifndef DISABLE_EVENT |
a7538db1 JH |
2101 | /* |
2102 | We use this callback to get observability and detail-level control | |
723fe533 JH |
2103 | for an exim TLS connection (either direction), raising a tls:cert event |
2104 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
2105 | can deny verification. |
2106 | ||
2107 | Return 0 for the handshake to continue or non-zero to terminate. | |
2108 | */ | |
2109 | ||
2110 | static int | |
723fe533 | 2111 | verify_cb(gnutls_session_t session) |
a7538db1 | 2112 | { |
27f19eb4 | 2113 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
2114 | unsigned int cert_list_size = 0; |
2115 | gnutls_x509_crt_t crt; | |
2116 | int rc; | |
b30275b8 | 2117 | uschar * yield; |
a7538db1 JH |
2118 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
2119 | ||
bd5b3f3c | 2120 | if ((cert_list = gnutls_certificate_get_peers(session, &cert_list_size))) |
a7538db1 JH |
2121 | while (cert_list_size--) |
2122 | { | |
bd5b3f3c | 2123 | if ((rc = import_cert(&cert_list[cert_list_size], &crt)) != GNUTLS_E_SUCCESS) |
a7538db1 JH |
2124 | { |
2125 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
2126 | cert_list_size, gnutls_strerror(rc)); | |
2127 | break; | |
2128 | } | |
2129 | ||
2130 | state->tlsp->peercert = crt; | |
b30275b8 JH |
2131 | if ((yield = event_raise(state->event_action, |
2132 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
2133 | { |
2134 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
2135 | "SSL verify denied by event-action: depth=%d: %s", |
2136 | cert_list_size, yield); | |
a7538db1 JH |
2137 | return 1; /* reject */ |
2138 | } | |
2139 | state->tlsp->peercert = NULL; | |
2140 | } | |
2141 | ||
2142 | return 0; | |
2143 | } | |
2144 | ||
2145 | #endif | |
44662487 JH |
2146 | |
2147 | ||
f20cfa4a JH |
2148 | static gstring * |
2149 | ddump(gnutls_datum_t * d) | |
2150 | { | |
2151 | gstring * g = string_get((d->size+1) * 2); | |
2152 | uschar * s = d->data; | |
2153 | for (unsigned i = d->size; i > 0; i--, s++) | |
2154 | { | |
2155 | g = string_catn(g, US "0123456789abcdef" + (*s >> 4), 1); | |
2156 | g = string_catn(g, US "0123456789abcdef" + (*s & 0xf), 1); | |
2157 | } | |
2158 | return g; | |
2159 | } | |
17c76198 | 2160 | |
dc6d1769 JH |
2161 | static void |
2162 | post_handshake_debug(exim_gnutls_state_st * state) | |
2163 | { | |
dc6d1769 JH |
2164 | #ifdef SUPPORT_GNUTLS_SESS_DESC |
2165 | debug_printf("%s\n", gnutls_session_get_desc(state->session)); | |
2166 | #endif | |
2167 | #ifdef SUPPORT_GNUTLS_KEYLOG | |
a8af957d | 2168 | # ifdef GNUTLS_TLS1_3 |
dc6d1769 | 2169 | if (gnutls_protocol_get_version(state->session) < GNUTLS_TLS1_3) |
a8af957d JH |
2170 | #else |
2171 | if (TRUE) | |
2172 | #endif | |
dc6d1769 JH |
2173 | { |
2174 | gnutls_datum_t c, s; | |
2175 | gstring * gc, * gs; | |
2176 | /* we only want the client random and the master secret */ | |
2177 | gnutls_session_get_random(state->session, &c, &s); | |
2178 | gnutls_session_get_master_secret(state->session, &s); | |
2179 | gc = ddump(&c); | |
2180 | gs = ddump(&s); | |
2181 | debug_printf("CLIENT_RANDOM %.*s %.*s\n", (int)gc->ptr, gc->s, (int)gs->ptr, gs->s); | |
2182 | } | |
2183 | else | |
2184 | debug_printf("To get keying info for TLS1.3 is hard:\n" | |
2185 | " set environment variable SSLKEYLOGFILE to a filename writable by uid exim\n" | |
2186 | " add SSLKEYLOGFILE to keep_environment in the exim config\n" | |
2187 | " run exim as root\n" | |
2188 | " if using sudo, add SSLKEYLOGFILE to env_keep in /etc/sudoers\n"); | |
2189 | #endif | |
2190 | } | |
2191 | ||
b10c87b3 JH |
2192 | |
2193 | #ifdef EXPERIMENTAL_TLS_RESUME | |
2194 | static int | |
2195 | tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
2196 | unsigned incoming, const gnutls_datum_t * msg) | |
2197 | { | |
2198 | DEBUG(D_tls) debug_printf("newticket cb\n"); | |
2199 | tls_in.resumption |= RESUME_CLIENT_REQUESTED; | |
2200 | return 0; | |
2201 | } | |
2202 | ||
2203 | static void | |
2204 | tls_server_resume_prehandshake(exim_gnutls_state_st * state) | |
2205 | { | |
2206 | /* Should the server offer session resumption? */ | |
2207 | tls_in.resumption = RESUME_SUPPORTED; | |
2208 | if (verify_check_host(&tls_resumption_hosts) == OK) | |
2209 | { | |
2210 | int rc; | |
2211 | /* GnuTLS appears to not do ticket overlap, but does emit a fresh ticket when | |
2212 | an offered resumption is unacceptable. We lose one resumption per ticket | |
2213 | lifetime, and sessions cannot be indefinitely re-used. There seems to be no | |
2214 | way (3.6.7) of changing the default number of 2 TLS1.3 tickets issued, but at | |
2215 | least they go out in a single packet. */ | |
2216 | ||
2217 | if (!(rc = gnutls_session_ticket_enable_server(state->session, | |
2218 | &server_sessticket_key))) | |
2219 | tls_in.resumption |= RESUME_SERVER_TICKET; | |
2220 | else | |
2221 | DEBUG(D_tls) | |
2222 | debug_printf("enabling session tickets: %s\n", US gnutls_strerror(rc)); | |
2223 | ||
2224 | /* Try to tell if we see a ticket request */ | |
2225 | gnutls_handshake_set_hook_function(state->session, | |
e5489333 | 2226 | GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb); |
b10c87b3 JH |
2227 | } |
2228 | } | |
2229 | ||
2230 | static void | |
2231 | tls_server_resume_posthandshake(exim_gnutls_state_st * state) | |
2232 | { | |
2233 | if (gnutls_session_resumption_requested(state->session)) | |
2234 | { | |
2235 | /* This tells us the client sent a full ticket. We use a | |
2236 | callback on session-ticket request, elsewhere, to tell | |
2237 | if a client asked for a ticket. */ | |
2238 | ||
2239 | tls_in.resumption |= RESUME_CLIENT_SUGGESTED; | |
2240 | DEBUG(D_tls) debug_printf("client requested resumption\n"); | |
2241 | } | |
2242 | if (gnutls_session_is_resumed(state->session)) | |
2243 | { | |
2244 | tls_in.resumption |= RESUME_USED; | |
2245 | DEBUG(D_tls) debug_printf("Session resumed\n"); | |
2246 | } | |
2247 | } | |
2248 | #endif | |
17c76198 PP |
2249 | /* ------------------------------------------------------------------------ */ |
2250 | /* Exported functions */ | |
2251 | ||
2252 | ||
2253 | ||
2254 | ||
059ec3d9 PH |
2255 | /************************************************* |
2256 | * Start a TLS session in a server * | |
2257 | *************************************************/ | |
2258 | ||
2259 | /* This is called when Exim is running as a server, after having received | |
2260 | the STARTTLS command. It must respond to that command, and then negotiate | |
2261 | a TLS session. | |
2262 | ||
2263 | Arguments: | |
83da1223 | 2264 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 2265 | errstr pointer to error string |
059ec3d9 PH |
2266 | |
2267 | Returns: OK on success | |
2268 | DEFER for errors before the start of the negotiation | |
4c04137d | 2269 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
2270 | continue running. |
2271 | */ | |
2272 | ||
2273 | int | |
cf0c6164 | 2274 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
2275 | { |
2276 | int rc; | |
cf0c6164 | 2277 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
2278 | |
2279 | /* Check for previous activation */ | |
74f1a423 | 2280 | if (tls_in.active.sock >= 0) |
059ec3d9 | 2281 | { |
48224640 | 2282 | tls_error(US"STARTTLS received after TLS started", US "", NULL, errstr); |
925ac8e4 | 2283 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
2284 | return FAIL; |
2285 | } | |
2286 | ||
2287 | /* Initialize the library. If it fails, it will already have logged the error | |
2288 | and sent an SMTP response. */ | |
2289 | ||
17c76198 | 2290 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 2291 | |
cf0c6164 | 2292 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 2293 | NULL, tls_verify_certificates, tls_crl, |
74f1a423 | 2294 | require_ciphers, &state, &tls_in, errstr)) != OK) return rc; |
059ec3d9 | 2295 | |
b10c87b3 JH |
2296 | #ifdef EXPERIMENTAL_TLS_RESUME |
2297 | tls_server_resume_prehandshake(state); | |
2298 | #endif | |
2299 | ||
059ec3d9 PH |
2300 | /* If this is a host for which certificate verification is mandatory or |
2301 | optional, set up appropriately. */ | |
2302 | ||
059ec3d9 | 2303 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 2304 | { |
e51c7be2 JH |
2305 | DEBUG(D_tls) |
2306 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
2307 | state->verify_requirement = VERIFY_REQUIRED; |
2308 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
2309 | } | |
059ec3d9 | 2310 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 2311 | { |
e51c7be2 JH |
2312 | DEBUG(D_tls) |
2313 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
2314 | state->verify_requirement = VERIFY_OPTIONAL; |
2315 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
2316 | } | |
2317 | else | |
2318 | { | |
e51c7be2 JH |
2319 | DEBUG(D_tls) |
2320 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
2321 | state->verify_requirement = VERIFY_NONE; |
2322 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
2323 | } | |
059ec3d9 | 2324 | |
0cbf2b82 | 2325 | #ifndef DISABLE_EVENT |
723fe533 JH |
2326 | if (event_action) |
2327 | { | |
2328 | state->event_action = event_action; | |
2329 | gnutls_session_set_ptr(state->session, state); | |
2330 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
2331 | } | |
2332 | #endif | |
2333 | ||
17c76198 PP |
2334 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
2335 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 2336 | |
17c76198 PP |
2337 | gnutls_handshake_set_post_client_hello_function(state->session, |
2338 | exim_sni_handling_cb); | |
059ec3d9 PH |
2339 | |
2340 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2341 | on connection, where outputting anything now upsets the clients and tends to | |
2342 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2343 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2344 | mode, the fflush() happens when smtp_getc() is called. */ | |
2345 | ||
817d9f57 | 2346 | if (!state->tlsp->on_connect) |
059ec3d9 | 2347 | { |
925ac8e4 | 2348 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 2349 | fflush(smtp_out); |
059ec3d9 PH |
2350 | } |
2351 | ||
2352 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
8008accd JH |
2353 | that the GnuTLS library doesn't. |
2354 | From 3.1.0 there is gnutls_handshake_set_timeout() - but it requires you | |
2355 | to set (and clear down afterwards) up a pull-timeout callback function that does | |
2356 | a select, so we're no better off unless avoiding signals becomes an issue. */ | |
059ec3d9 | 2357 | |
17c76198 | 2358 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
2359 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
2360 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
2361 | state->fd_in = fileno(smtp_in); |
2362 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
2363 | |
2364 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2365 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
17c76198 | 2366 | do |
17c76198 | 2367 | rc = gnutls_handshake(state->session); |
157a7880 | 2368 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
c2a1bba0 | 2369 | ALARM_CLR(0); |
059ec3d9 | 2370 | |
17c76198 | 2371 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 2372 | { |
059ec3d9 PH |
2373 | /* It seems that, except in the case of a timeout, we have to close the |
2374 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
2375 | until the server times out. */ | |
2376 | ||
60d10ce7 | 2377 | if (sigalrm_seen) |
ad7fc6eb | 2378 | { |
48224640 | 2379 | tls_error(US"gnutls_handshake", US"timed out", NULL, errstr); |
ad7fc6eb JH |
2380 | gnutls_db_remove_session(state->session); |
2381 | } | |
60d10ce7 | 2382 | else |
059ec3d9 | 2383 | { |
452a164f | 2384 | tls_error_gnu(US"gnutls_handshake", rc, NULL, errstr); |
f5d25c2b | 2385 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 2386 | gnutls_deinit(state->session); |
ed62aae3 | 2387 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 2388 | millisleep(500); |
ad7fc6eb | 2389 | shutdown(state->fd_out, SHUT_WR); |
d7978c0f | 2390 | for (int i = 1024; fgetc(smtp_in) != EOF && i > 0; ) i--; /* drain skt */ |
f1e894f3 PH |
2391 | (void)fclose(smtp_out); |
2392 | (void)fclose(smtp_in); | |
60d10ce7 | 2393 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
2394 | } |
2395 | ||
2396 | return FAIL; | |
2397 | } | |
2398 | ||
b10c87b3 JH |
2399 | #ifdef EXPERIMENTAL_TLS_RESUME |
2400 | tls_server_resume_posthandshake(state); | |
2401 | #endif | |
2402 | ||
dc6d1769 | 2403 | DEBUG(D_tls) post_handshake_debug(state); |
059ec3d9 | 2404 | |
17c76198 PP |
2405 | /* Verify after the fact */ |
2406 | ||
899b8bbc | 2407 | if (!verify_certificate(state, errstr)) |
059ec3d9 | 2408 | { |
9d1c15ef | 2409 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 2410 | { |
cf0c6164 | 2411 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 2412 | return FAIL; |
17c76198 | 2413 | } |
9d1c15ef JH |
2414 | DEBUG(D_tls) |
2415 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 2416 | *errstr); |
059ec3d9 PH |
2417 | } |
2418 | ||
17c76198 PP |
2419 | /* Sets various Exim expansion variables; always safe within server */ |
2420 | ||
9d1c15ef | 2421 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
2422 | |
2423 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2424 | and initialize appropriately. */ | |
2425 | ||
17c76198 | 2426 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
2427 | |
2428 | receive_getc = tls_getc; | |
0d81dabc | 2429 | receive_getbuf = tls_getbuf; |
584e96c6 | 2430 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2431 | receive_ungetc = tls_ungetc; |
2432 | receive_feof = tls_feof; | |
2433 | receive_ferror = tls_ferror; | |
58eb016e | 2434 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2435 | |
059ec3d9 PH |
2436 | return OK; |
2437 | } | |
2438 | ||
2439 | ||
2440 | ||
2441 | ||
aa2a70ba JH |
2442 | static void |
2443 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
2444 | smtp_transport_options_block * ob) | |
2445 | { | |
3fb3231c | 2446 | if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 2447 | { |
4af0d74a | 2448 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 2449 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2450 | string_domain_utf8_to_alabel(host->name, NULL); |
2451 | #else | |
2452 | host->name; | |
2453 | #endif | |
aa2a70ba JH |
2454 | DEBUG(D_tls) |
2455 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
2456 | state->exp_tls_verify_cert_hostnames); | |
2457 | } | |
2458 | } | |
aa2a70ba JH |
2459 | |
2460 | ||
899b8bbc JH |
2461 | |
2462 | ||
2463 | #ifdef SUPPORT_DANE | |
2464 | /* Given our list of RRs from the TLSA lookup, build a lookup block in | |
2465 | GnuTLS-DANE's preferred format. Hang it on the state str for later | |
2466 | use in DANE verification. | |
2467 | ||
2468 | We point at the dnsa data not copy it, so it must remain valid until | |
2469 | after verification is done.*/ | |
2470 | ||
3674140c | 2471 | static BOOL |
899b8bbc JH |
2472 | dane_tlsa_load(exim_gnutls_state_st * state, dns_answer * dnsa) |
2473 | { | |
899b8bbc JH |
2474 | dns_scan dnss; |
2475 | int i; | |
2476 | const char ** dane_data; | |
2477 | int * dane_data_len; | |
2478 | ||
d7978c0f JH |
2479 | i = 1; |
2480 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; | |
899b8bbc JH |
2481 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
2482 | ) if (rr->type == T_TLSA) i++; | |
2483 | ||
f3ebb786 JH |
2484 | dane_data = store_get(i * sizeof(uschar *), FALSE); |
2485 | dane_data_len = store_get(i * sizeof(int), FALSE); | |
899b8bbc | 2486 | |
d7978c0f JH |
2487 | i = 0; |
2488 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; | |
899b8bbc | 2489 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
1b76ad22 | 2490 | ) if (rr->type == T_TLSA && rr->size > 3) |
899b8bbc JH |
2491 | { |
2492 | const uschar * p = rr->data; | |
f3ebb786 | 2493 | /*XXX need somehow to mark rr and its data as tainted. Doues this mean copying it? */ |
3674140c JH |
2494 | uint8_t usage = p[0], sel = p[1], type = p[2]; |
2495 | ||
2496 | DEBUG(D_tls) | |
2497 | debug_printf("TLSA: %d %d %d size %d\n", usage, sel, type, rr->size); | |
2498 | ||
94c13285 JH |
2499 | if ( (usage != DANESSL_USAGE_DANE_TA && usage != DANESSL_USAGE_DANE_EE) |
2500 | || (sel != 0 && sel != 1) | |
2501 | ) | |
2502 | continue; | |
3674140c JH |
2503 | switch(type) |
2504 | { | |
2505 | case 0: /* Full: cannot check at present */ | |
2506 | break; | |
2507 | case 1: if (rr->size != 3 + 256/8) continue; /* sha2-256 */ | |
2508 | break; | |
2509 | case 2: if (rr->size != 3 + 512/8) continue; /* sha2-512 */ | |
2510 | break; | |
2511 | default: continue; | |
2512 | } | |
899b8bbc JH |
2513 | |
2514 | tls_out.tlsa_usage |= 1<<usage; | |
48224640 | 2515 | dane_data[i] = CS p; |
899b8bbc JH |
2516 | dane_data_len[i++] = rr->size; |
2517 | } | |
3674140c JH |
2518 | |
2519 | if (!i) return FALSE; | |
2520 | ||
899b8bbc JH |
2521 | dane_data[i] = NULL; |
2522 | dane_data_len[i] = 0; | |
2523 | ||
2524 | state->dane_data = (char * const *)dane_data; | |
2525 | state->dane_data_len = dane_data_len; | |
3674140c | 2526 | return TRUE; |
899b8bbc JH |
2527 | } |
2528 | #endif | |
2529 | ||
2530 | ||
2531 | ||
b10c87b3 JH |
2532 | #ifdef EXPERIMENTAL_TLS_RESUME |
2533 | /* On the client, get any stashed session for the given IP from hints db | |
2534 | and apply it to the ssl-connection for attempted resumption. Although | |
2535 | there is a gnutls_session_ticket_enable_client() interface it is | |
2536 | documented as unnecessary (as of 3.6.7) as "session tickets are emabled | |
2537 | by deafult". There seems to be no way to disable them, so even hosts not | |
2538 | enabled by the transport option will be sent a ticket request. We will | |
2539 | however avoid storing and retrieving session information. */ | |
2540 | ||
2541 | static void | |
2542 | tls_retrieve_session(tls_support * tlsp, gnutls_session_t session, | |
2543 | host_item * host, smtp_transport_options_block * ob) | |
2544 | { | |
2545 | tlsp->resumption = RESUME_SUPPORTED; | |
2546 | if (verify_check_given_host(CUSS &ob->tls_resumption_hosts, host) == OK) | |
2547 | { | |
2548 | dbdata_tls_session * dt; | |
2549 | int len, rc; | |
2550 | open_db dbblock, * dbm_file; | |
2551 | ||
2552 | DEBUG(D_tls) | |
2553 | debug_printf("check for resumable session for %s\n", host->address); | |
2554 | tlsp->host_resumable = TRUE; | |
2555 | tlsp->resumption |= RESUME_CLIENT_REQUESTED; | |
2556 | if ((dbm_file = dbfn_open(US"tls", O_RDONLY, &dbblock, FALSE, FALSE))) | |
2557 | { | |
dea4b568 JH |
2558 | /* Key for the db is the IP. We'd like to filter the retrieved session |
2559 | for ticket advisory expiry, but 3.6.1 seems to give no access to that */ | |
2560 | ||
b10c87b3 JH |
2561 | if ((dt = dbfn_read_with_length(dbm_file, host->address, &len))) |
2562 | if (!(rc = gnutls_session_set_data(session, | |
2563 | CUS dt->session, (size_t)len - sizeof(dbdata_tls_session)))) | |
2564 | { | |
2565 | DEBUG(D_tls) debug_printf("good session\n"); | |
2566 | tlsp->resumption |= RESUME_CLIENT_SUGGESTED; | |
2567 | } | |
2568 | else DEBUG(D_tls) debug_printf("setting session resumption data: %s\n", | |
2569 | US gnutls_strerror(rc)); | |
2570 | dbfn_close(dbm_file); | |
2571 | } | |
2572 | } | |
2573 | } | |
2574 | ||
2575 | ||
2576 | static void | |
2577 | tls_save_session(tls_support * tlsp, gnutls_session_t session, const host_item * host) | |
2578 | { | |
2579 | /* TLS 1.2 - we get both the callback and the direct posthandshake call, | |
2580 | but this flag is not set until the second. TLS 1.3 it's the other way about. | |
2581 | Keep both calls as the session data cannot be extracted before handshake | |
2582 | completes. */ | |
2583 | ||
2584 | if (gnutls_session_get_flags(session) & GNUTLS_SFLAGS_SESSION_TICKET) | |
2585 | { | |
2586 | gnutls_datum_t tkt; | |
2587 | int rc; | |
2588 | ||
2589 | DEBUG(D_tls) debug_printf("server offered session ticket\n"); | |
2590 | tlsp->ticket_received = TRUE; | |
2591 | tlsp->resumption |= RESUME_SERVER_TICKET; | |
2592 | ||
2593 | if (tlsp->host_resumable) | |
2594 | if (!(rc = gnutls_session_get_data2(session, &tkt))) | |
2595 | { | |
2596 | open_db dbblock, * dbm_file; | |
2597 | int dlen = sizeof(dbdata_tls_session) + tkt.size; | |
f3ebb786 | 2598 | dbdata_tls_session * dt = store_get(dlen, TRUE); |
b10c87b3 JH |
2599 | |
2600 | DEBUG(D_tls) debug_printf("session data size %u\n", (unsigned)tkt.size); | |
2601 | memcpy(dt->session, tkt.data, tkt.size); | |
2602 | gnutls_free(tkt.data); | |
2603 | ||
2604 | if ((dbm_file = dbfn_open(US"tls", O_RDWR, &dbblock, FALSE, FALSE))) | |
2605 | { | |
2606 | /* key for the db is the IP */ | |
2607 | dbfn_delete(dbm_file, host->address); | |
2608 | dbfn_write(dbm_file, host->address, dt, dlen); | |
2609 | dbfn_close(dbm_file); | |
2610 | ||
2611 | DEBUG(D_tls) | |
2612 | debug_printf("wrote session db (len %u)\n", (unsigned)dlen); | |
2613 | } | |
2614 | } | |
2615 | else DEBUG(D_tls) | |
2616 | debug_printf("extract session data: %s\n", US gnutls_strerror(rc)); | |
2617 | } | |
2618 | } | |
2619 | ||
2620 | ||
2621 | /* With a TLS1.3 session, the ticket(s) are not seen until | |
2622 | the first data read is attempted. And there's often two of them. | |
2623 | Pick them up with this callback. We are also called for 1.2 | |
2624 | but we do nothing. | |
2625 | */ | |
2626 | static int | |
2627 | tls_client_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when, | |
2628 | unsigned incoming, const gnutls_datum_t * msg) | |
2629 | { | |
2630 | exim_gnutls_state_st * state = gnutls_session_get_ptr(sess); | |
2631 | tls_support * tlsp = state->tlsp; | |
2632 | ||
2633 | DEBUG(D_tls) debug_printf("newticket cb\n"); | |
2634 | ||
2635 | if (!tlsp->ticket_received) | |
2636 | tls_save_session(tlsp, sess, state->host); | |
2637 | return 0; | |
2638 | } | |
2639 | ||
2640 | ||
2641 | static void | |
2642 | tls_client_resume_prehandshake(exim_gnutls_state_st * state, | |
2643 | tls_support * tlsp, host_item * host, | |
2644 | smtp_transport_options_block * ob) | |
2645 | { | |
2646 | gnutls_session_set_ptr(state->session, state); | |
2647 | gnutls_handshake_set_hook_function(state->session, | |
2648 | GNUTLS_HANDSHAKE_NEW_SESSION_TICKET, GNUTLS_HOOK_POST, tls_client_ticket_cb); | |
2649 | ||
2650 | tls_retrieve_session(tlsp, state->session, host, ob); | |
2651 | } | |
2652 | ||
2653 | static void | |
2654 | tls_client_resume_posthandshake(exim_gnutls_state_st * state, | |
2655 | tls_support * tlsp, host_item * host) | |
2656 | { | |
2657 | if (gnutls_session_is_resumed(state->session)) | |
2658 | { | |
2659 | DEBUG(D_tls) debug_printf("Session resumed\n"); | |
2660 | tlsp->resumption |= RESUME_USED; | |
2661 | } | |
2662 | ||
2663 | tls_save_session(tlsp, state->session, host); | |
2664 | } | |
2665 | #endif /* EXPERIMENTAL_TLS_RESUME */ | |
2666 | ||
2667 | ||
059ec3d9 PH |
2668 | /************************************************* |
2669 | * Start a TLS session in a client * | |
2670 | *************************************************/ | |
2671 | ||
2672 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2673 | ||
2674 | Arguments: | |
c05bdbd6 JH |
2675 | cctx connection context |
2676 | conn_args connection details | |
2677 | cookie datum for randomness (not used) | |
2678 | tlsp record details of channel configuration here; must be non-NULL | |
2679 | errstr error string pointer | |
2680 | ||
2681 | Returns: TRUE for success with TLS session context set in smtp context, | |
2682 | FALSE on error | |
059ec3d9 PH |
2683 | */ |
2684 | ||
c05bdbd6 JH |
2685 | BOOL |
2686 | tls_client_start(client_conn_ctx * cctx, smtp_connect_args * conn_args, | |
2687 | void * cookie ARG_UNUSED, | |
2688 | tls_support * tlsp, uschar ** errstr) | |
059ec3d9 | 2689 | { |
c05bdbd6 JH |
2690 | host_item * host = conn_args->host; /* for msgs and option-tests */ |
2691 | transport_instance * tb = conn_args->tblock; /* always smtp or NULL */ | |
2692 | smtp_transport_options_block * ob = tb | |
afdb5e9c JH |
2693 | ? (smtp_transport_options_block *)tb->options_block |
2694 | : &smtp_transport_option_defaults; | |
059ec3d9 | 2695 | int rc; |
899b8bbc | 2696 | exim_gnutls_state_st * state = NULL; |
c05bdbd6 | 2697 | uschar * cipher_list = NULL; |
74f1a423 | 2698 | |
f2de3a33 | 2699 | #ifndef DISABLE_OCSP |
5130845b | 2700 | BOOL require_ocsp = |
3fb3231c | 2701 | verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; |
44662487 | 2702 | BOOL request_ocsp = require_ocsp ? TRUE |
3fb3231c | 2703 | : verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 2704 | #endif |
059ec3d9 | 2705 | |
c05bdbd6 | 2706 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", cctx->sock); |
059ec3d9 | 2707 | |
5ec37a55 | 2708 | #ifdef SUPPORT_DANE |
c05bdbd6 JH |
2709 | /* If dane is flagged, have either request or require dane for this host, and |
2710 | a TLSA record found. Therefore, dane verify required. Which implies cert must | |
2711 | be requested and supplied, dane verify must pass, and cert verify irrelevant | |
2712 | (incl. hostnames), and (caller handled) require_tls */ | |
2713 | ||
2714 | if (conn_args->dane && ob->dane_require_tls_ciphers) | |
5ec37a55 PP |
2715 | { |
2716 | /* not using expand_check_tlsvar because not yet in state */ | |
2717 | if (!expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2718 | &cipher_list, errstr)) | |
c05bdbd6 | 2719 | return FALSE; |
cf260049 JH |
2720 | cipher_list = cipher_list && *cipher_list |
2721 | ? ob->dane_require_tls_ciphers : ob->tls_require_ciphers; | |
5ec37a55 PP |
2722 | } |
2723 | #endif | |
2724 | ||
2725 | if (!cipher_list) | |
2726 | cipher_list = ob->tls_require_ciphers; | |
2727 | ||
74f1a423 | 2728 | if (tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
65867078 | 2729 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, |
74f1a423 | 2730 | cipher_list, &state, tlsp, errstr) != OK) |
c05bdbd6 | 2731 | return FALSE; |
059ec3d9 | 2732 | |
54c90be1 | 2733 | { |
65867078 JH |
2734 | int dh_min_bits = ob->tls_dh_min_bits; |
2735 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2736 | { | |
2737 | DEBUG(D_tls) | |
2738 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2739 | " clamping %d up to %d\n", | |
2740 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2741 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2742 | } | |
54c90be1 | 2743 | |
65867078 JH |
2744 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2745 | " acceptable bits to %d\n", | |
2746 | dh_min_bits); | |
2747 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2748 | } | |
83da1223 | 2749 | |
94431adb | 2750 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2751 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2752 | the specified host patterns if one of them is defined */ | |
2753 | ||
899b8bbc | 2754 | #ifdef SUPPORT_DANE |
c05bdbd6 | 2755 | if (conn_args->dane && dane_tlsa_load(state, &conn_args->tlsa_dnsa)) |
899b8bbc JH |
2756 | { |
2757 | DEBUG(D_tls) | |
2758 | debug_printf("TLS: server certificate DANE required.\n"); | |
2759 | state->verify_requirement = VERIFY_DANE; | |
2760 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
899b8bbc JH |
2761 | } |
2762 | else | |
2763 | #endif | |
2764 | if ( ( state->exp_tls_verify_certificates | |
2765 | && !ob->tls_verify_hosts | |
2766 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2767 | ) | |
3fb3231c | 2768 | || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK |
899b8bbc | 2769 | ) |
17c76198 | 2770 | { |
aa2a70ba | 2771 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2772 | DEBUG(D_tls) |
2773 | debug_printf("TLS: server certificate verification required.\n"); | |
2774 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2775 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2776 | } | |
3fb3231c | 2777 | else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2778 | { |
aa2a70ba | 2779 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2780 | DEBUG(D_tls) |
2781 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2782 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2783 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2784 | } | |
2785 | else | |
2786 | { | |
e51c7be2 JH |
2787 | DEBUG(D_tls) |
2788 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2789 | state->verify_requirement = VERIFY_NONE; |
2790 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2791 | } |
059ec3d9 | 2792 | |
f2de3a33 JH |
2793 | #ifndef DISABLE_OCSP |
2794 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2795 | if (request_ocsp) |
9d1c15ef JH |
2796 | { |
2797 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2798 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2799 | NULL, 0, NULL)) != OK) | |
74f1a423 | 2800 | { |
452a164f | 2801 | tls_error_gnu(US"cert-status-req", rc, state->host, errstr); |
c05bdbd6 | 2802 | return FALSE; |
74f1a423 JH |
2803 | } |
2804 | tlsp->ocsp = OCSP_NOT_RESP; | |
9d1c15ef | 2805 | } |
2b4a568d JH |
2806 | #endif |
2807 | ||
b10c87b3 JH |
2808 | #ifdef EXPERIMENTAL_TLS_RESUME |
2809 | tls_client_resume_prehandshake(state, tlsp, host, ob); | |
2810 | #endif | |
2811 | ||
0cbf2b82 | 2812 | #ifndef DISABLE_EVENT |
afdb5e9c | 2813 | if (tb && tb->event_action) |
a7538db1 | 2814 | { |
774ef2d7 | 2815 | state->event_action = tb->event_action; |
a7538db1 | 2816 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2817 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2818 | } |
2819 | #endif | |
2820 | ||
c05bdbd6 JH |
2821 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) cctx->sock); |
2822 | state->fd_in = cctx->sock; | |
2823 | state->fd_out = cctx->sock; | |
059ec3d9 | 2824 | |
9d1c15ef | 2825 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2826 | /* There doesn't seem to be a built-in timeout on connection. */ |
2827 | ||
2828 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2829 | ALARM(ob->command_timeout); |
17c76198 | 2830 | do |
17c76198 | 2831 | rc = gnutls_handshake(state->session); |
f1fed05b | 2832 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
c2a1bba0 | 2833 | ALARM_CLR(0); |
059ec3d9 | 2834 | |
4fe99a6c | 2835 | if (rc != GNUTLS_E_SUCCESS) |
74f1a423 | 2836 | { |
60d10ce7 JH |
2837 | if (sigalrm_seen) |
2838 | { | |
2839 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
48224640 | 2840 | tls_error(US"gnutls_handshake", US"timed out", state->host, errstr); |
60d10ce7 JH |
2841 | } |
2842 | else | |
452a164f | 2843 | tls_error_gnu(US"gnutls_handshake", rc, state->host, errstr); |
c05bdbd6 | 2844 | return FALSE; |
74f1a423 | 2845 | } |
4fe99a6c | 2846 | |
dc6d1769 | 2847 | DEBUG(D_tls) post_handshake_debug(state); |
059ec3d9 | 2848 | |
17c76198 | 2849 | /* Verify late */ |
059ec3d9 | 2850 | |
899b8bbc | 2851 | if (!verify_certificate(state, errstr)) |
74f1a423 JH |
2852 | { |
2853 | tls_error(US"certificate verification failed", *errstr, state->host, errstr); | |
c05bdbd6 | 2854 | return FALSE; |
74f1a423 | 2855 | } |
059ec3d9 | 2856 | |
f2de3a33 | 2857 | #ifndef DISABLE_OCSP |
7a501c87 | 2858 | if (request_ocsp) |
2b4a568d JH |
2859 | { |
2860 | DEBUG(D_tls) | |
2861 | { | |
2862 | gnutls_datum_t stapling; | |
2863 | gnutls_ocsp_resp_t resp; | |
2864 | gnutls_datum_t printed; | |
2865 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2866 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2867 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2868 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2869 | ) | |
2870 | { | |
65867078 | 2871 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2872 | gnutls_free(printed.data); |
2873 | } | |
2874 | else | |
452a164f | 2875 | (void) tls_error_gnu(US"ocsp decode", rc, state->host, errstr); |
2b4a568d JH |
2876 | } |
2877 | ||
2b4a568d | 2878 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 | 2879 | { |
74f1a423 JH |
2880 | tlsp->ocsp = OCSP_FAILED; |
2881 | tls_error(US"certificate status check failed", NULL, state->host, errstr); | |
7a501c87 JH |
2882 | if (require_ocsp) |
2883 | return FALSE; | |
2884 | } | |
2885 | else | |
2886 | { | |
2887 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); | |
2888 | tlsp->ocsp = OCSP_VFIED; | |
018058b2 | 2889 | } |
2b4a568d JH |
2890 | } |
2891 | #endif | |
2892 | ||
b10c87b3 JH |
2893 | #ifdef EXPERIMENTAL_TLS_RESUME |
2894 | tls_client_resume_posthandshake(state, tlsp, host); | |
2895 | #endif | |
059ec3d9 | 2896 | |
4fe99a6c | 2897 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2898 | |
9d1c15ef | 2899 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2900 | |
c05bdbd6 JH |
2901 | cctx->tls_ctx = state; |
2902 | return TRUE; | |
059ec3d9 PH |
2903 | } |
2904 | ||
2905 | ||
2906 | ||
17c76198 | 2907 | |
059ec3d9 | 2908 | /************************************************* |
17c76198 | 2909 | * Close down a TLS session * |
059ec3d9 PH |
2910 | *************************************************/ |
2911 | ||
17c76198 PP |
2912 | /* This is also called from within a delivery subprocess forked from the |
2913 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2914 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2915 | |
dec766a1 | 2916 | Arguments: |
74f1a423 | 2917 | ct_ctx client context pointer, or NULL for the one global server context |
dec766a1 | 2918 | shutdown 1 if TLS close-alert is to be sent, |
afdb5e9c | 2919 | 2 if also response to be waited for |
dec766a1 | 2920 | |
17c76198 | 2921 | Returns: nothing |
059ec3d9 PH |
2922 | */ |
2923 | ||
17c76198 | 2924 | void |
74f1a423 | 2925 | tls_close(void * ct_ctx, int shutdown) |
059ec3d9 | 2926 | { |
74f1a423 | 2927 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
bd231acd | 2928 | tls_support * tlsp = state->tlsp; |
059ec3d9 | 2929 | |
bd231acd | 2930 | if (!tlsp || tlsp->active.sock < 0) return; /* TLS was not active */ |
17c76198 PP |
2931 | |
2932 | if (shutdown) | |
2933 | { | |
dec766a1 WB |
2934 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", |
2935 | shutdown > 1 ? " (with response-wait)" : ""); | |
2936 | ||
c2a1bba0 | 2937 | ALARM(2); |
dec766a1 | 2938 | gnutls_bye(state->session, shutdown > 1 ? GNUTLS_SHUT_RDWR : GNUTLS_SHUT_WR); |
c2a1bba0 | 2939 | ALARM_CLR(0); |
17c76198 PP |
2940 | } |
2941 | ||
bd231acd JH |
2942 | if (!ct_ctx) /* server */ |
2943 | { | |
2944 | receive_getc = smtp_getc; | |
2945 | receive_getbuf = smtp_getbuf; | |
2946 | receive_get_cache = smtp_get_cache; | |
2947 | receive_ungetc = smtp_ungetc; | |
2948 | receive_feof = smtp_feof; | |
2949 | receive_ferror = smtp_ferror; | |
2950 | receive_smtp_buffered = smtp_buffered; | |
2951 | } | |
2952 | ||
17c76198 | 2953 | gnutls_deinit(state->session); |
ed62aae3 HSHR |
2954 | gnutls_certificate_free_credentials(state->x509_cred); |
2955 | ||
bd231acd JH |
2956 | tlsp->active.sock = -1; |
2957 | tlsp->active.tls_ctx = NULL; | |
2958 | /* Leave bits, peercert, cipher, peerdn, certificate_verified set, for logging */ | |
2959 | tls_channelbinding_b64 = NULL; | |
2960 | ||
17c76198 | 2961 | |
b808677c | 2962 | if (state->xfer_buffer) store_free(state->xfer_buffer); |
17c76198 | 2963 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
059ec3d9 PH |
2964 | } |
2965 | ||
2966 | ||
2967 | ||
17c76198 | 2968 | |
0d81dabc JH |
2969 | static BOOL |
2970 | tls_refill(unsigned lim) | |
2971 | { | |
2972 | exim_gnutls_state_st * state = &state_server; | |
2973 | ssize_t inbytes; | |
2974 | ||
2975 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2976 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2977 | ||
f1fed05b | 2978 | sigalrm_seen = FALSE; |
c2a1bba0 | 2979 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
4896a319 AM |
2980 | |
2981 | do | |
2982 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2983 | MIN(ssl_xfer_buffer_size, lim)); | |
2984 | while (inbytes == GNUTLS_E_AGAIN); | |
2985 | ||
c2a1bba0 | 2986 | if (smtp_receive_timeout > 0) ALARM_CLR(0); |
9723f966 JH |
2987 | |
2988 | if (had_command_timeout) /* set by signal handler */ | |
2989 | smtp_command_timeout_exit(); /* does not return */ | |
2990 | if (had_command_sigterm) | |
2991 | smtp_command_sigterm_exit(); | |
2992 | if (had_data_timeout) | |
2993 | smtp_data_timeout_exit(); | |
2994 | if (had_data_sigint) | |
2995 | smtp_data_sigint_exit(); | |
2996 | ||
2997 | /* Timeouts do not get this far. A zero-byte return appears to mean that the | |
2998 | TLS session has been closed down, not that the socket itself has been closed | |
2999 | down. Revert to non-TLS handling. */ | |
0d81dabc JH |
3000 | |
3001 | if (sigalrm_seen) | |
3002 | { | |
3003 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
8b77d27a | 3004 | state->xfer_error = TRUE; |
0d81dabc JH |
3005 | return FALSE; |
3006 | } | |
3007 | ||
3008 | else if (inbytes == 0) | |
3009 | { | |
3010 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
bd231acd | 3011 | tls_close(NULL, TLS_NO_SHUTDOWN); |
0d81dabc JH |
3012 | return FALSE; |
3013 | } | |
3014 | ||
3015 | /* Handle genuine errors */ | |
3016 | ||
3017 | else if (inbytes < 0) | |
3018 | { | |
95f52235 | 3019 | DEBUG(D_tls) debug_printf("%s: err from gnutls_record_recv\n", __FUNCTION__); |
0d81dabc | 3020 | record_io_error(state, (int) inbytes, US"recv", NULL); |
8b77d27a | 3021 | state->xfer_error = TRUE; |
0d81dabc JH |
3022 | return FALSE; |
3023 | } | |
3024 | #ifndef DISABLE_DKIM | |
3025 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
3026 | #endif | |
3027 | state->xfer_buffer_hwm = (int) inbytes; | |
3028 | state->xfer_buffer_lwm = 0; | |
3029 | return TRUE; | |
3030 | } | |
3031 | ||
059ec3d9 PH |
3032 | /************************************************* |
3033 | * TLS version of getc * | |
3034 | *************************************************/ | |
3035 | ||
3036 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
3037 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 3038 | Only used by the server-side TLS. |
059ec3d9 | 3039 | |
17c76198 PP |
3040 | This feeds DKIM and should be used for all message-body reads. |
3041 | ||
aded2255 | 3042 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 PH |
3043 | Returns: the next character or EOF |
3044 | */ | |
3045 | ||
3046 | int | |
bd8fbe36 | 3047 | tls_getc(unsigned lim) |
059ec3d9 | 3048 | { |
0d81dabc | 3049 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 3050 | |
0d81dabc JH |
3051 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
3052 | if (!tls_refill(lim)) | |
3053 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 3054 | |
0d81dabc | 3055 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 3056 | |
0d81dabc JH |
3057 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
3058 | } | |
059ec3d9 | 3059 | |
0d81dabc JH |
3060 | uschar * |
3061 | tls_getbuf(unsigned * len) | |
3062 | { | |
3063 | exim_gnutls_state_st * state = &state_server; | |
3064 | unsigned size; | |
3065 | uschar * buf; | |
059ec3d9 | 3066 | |
0d81dabc JH |
3067 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
3068 | if (!tls_refill(*len)) | |
059ec3d9 | 3069 | { |
0d81dabc JH |
3070 | if (!state->xfer_error) return smtp_getbuf(len); |
3071 | *len = 0; | |
3072 | return NULL; | |
059ec3d9 | 3073 | } |
059ec3d9 | 3074 | |
0d81dabc JH |
3075 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
3076 | size = *len; | |
3077 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
3078 | state->xfer_buffer_lwm += size; | |
3079 | *len = size; | |
3080 | return buf; | |
059ec3d9 PH |
3081 | } |
3082 | ||
0d81dabc | 3083 | |
584e96c6 JH |
3084 | void |
3085 | tls_get_cache() | |
3086 | { | |
9960d1e5 | 3087 | #ifndef DISABLE_DKIM |
584e96c6 JH |
3088 | exim_gnutls_state_st * state = &state_server; |
3089 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
3090 | if (n > 0) | |
3091 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 3092 | #endif |
9960d1e5 | 3093 | } |
584e96c6 | 3094 | |
059ec3d9 | 3095 | |
925ac8e4 JH |
3096 | BOOL |
3097 | tls_could_read(void) | |
3098 | { | |
3099 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
3100 | || gnutls_record_check_pending(state_server.session) > 0; | |
3101 | } | |
3102 | ||
3103 | ||
059ec3d9 | 3104 | |
17c76198 | 3105 | |
059ec3d9 PH |
3106 | /************************************************* |
3107 | * Read bytes from TLS channel * | |
3108 | *************************************************/ | |
3109 | ||
17c76198 PP |
3110 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
3111 | then the caller must feed DKIM. | |
817d9f57 | 3112 | |
059ec3d9 | 3113 | Arguments: |
74f1a423 | 3114 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
3115 | buff buffer of data |
3116 | len size of buffer | |
3117 | ||
3118 | Returns: the number of bytes read | |
afdb5e9c | 3119 | -1 after a failed read, including EOF |
059ec3d9 PH |
3120 | */ |
3121 | ||
3122 | int | |
74f1a423 | 3123 | tls_read(void * ct_ctx, uschar *buff, size_t len) |
059ec3d9 | 3124 | { |
74f1a423 | 3125 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
17c76198 | 3126 | ssize_t inbytes; |
059ec3d9 | 3127 | |
17c76198 PP |
3128 | if (len > INT_MAX) |
3129 | len = INT_MAX; | |
059ec3d9 | 3130 | |
17c76198 PP |
3131 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
3132 | DEBUG(D_tls) | |
3133 | debug_printf("*** PROBABLY A BUG *** " \ | |
3134 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
3135 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
3136 | ||
3137 | DEBUG(D_tls) | |
3138 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
3139 | state->session, buff, len); | |
3140 | ||
4896a319 AM |
3141 | do |
3142 | inbytes = gnutls_record_recv(state->session, buff, len); | |
3143 | while (inbytes == GNUTLS_E_AGAIN); | |
3144 | ||
059ec3d9 PH |
3145 | if (inbytes > 0) return inbytes; |
3146 | if (inbytes == 0) | |
3147 | { | |
3148 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
3149 | } | |
5fd28bb8 | 3150 | else |
4896a319 | 3151 | { |
95f52235 | 3152 | DEBUG(D_tls) debug_printf("%s: err from gnutls_record_recv\n", __FUNCTION__); |
4896a319 AM |
3153 | record_io_error(state, (int)inbytes, US"recv", NULL); |
3154 | } | |
059ec3d9 PH |
3155 | |
3156 | return -1; | |
3157 | } | |
3158 | ||
3159 | ||
3160 | ||
17c76198 | 3161 | |
059ec3d9 PH |
3162 | /************************************************* |
3163 | * Write bytes down TLS channel * | |
3164 | *************************************************/ | |
3165 | ||
3166 | /* | |
3167 | Arguments: | |
74f1a423 | 3168 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
3169 | buff buffer of data |
3170 | len number of bytes | |
925ac8e4 | 3171 | more more data expected soon |
059ec3d9 PH |
3172 | |
3173 | Returns: the number of bytes after a successful write, | |
3174 | -1 after a failed write | |
3175 | */ | |
3176 | ||
3177 | int | |
74f1a423 | 3178 | tls_write(void * ct_ctx, const uschar * buff, size_t len, BOOL more) |
059ec3d9 | 3179 | { |
17c76198 PP |
3180 | ssize_t outbytes; |
3181 | size_t left = len; | |
74f1a423 | 3182 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
925ac8e4 JH |
3183 | #ifdef SUPPORT_CORK |
3184 | static BOOL corked = FALSE; | |
3185 | ||
3186 | if (more && !corked) gnutls_record_cork(state->session); | |
3187 | #endif | |
3188 | ||
3189 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
3190 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 3191 | |
059ec3d9 PH |
3192 | while (left > 0) |
3193 | { | |
17c76198 PP |
3194 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
3195 | buff, left); | |
4896a319 AM |
3196 | |
3197 | do | |
3198 | outbytes = gnutls_record_send(state->session, buff, left); | |
3199 | while (outbytes == GNUTLS_E_AGAIN); | |
059ec3d9 | 3200 | |
17c76198 | 3201 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
3202 | if (outbytes < 0) |
3203 | { | |
1b76ad22 | 3204 | DEBUG(D_tls) debug_printf("%s: gnutls_record_send err\n", __FUNCTION__); |
17c76198 | 3205 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
3206 | return -1; |
3207 | } | |
3208 | if (outbytes == 0) | |
3209 | { | |
17c76198 | 3210 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
3211 | return -1; |
3212 | } | |
3213 | ||
3214 | left -= outbytes; | |
3215 | buff += outbytes; | |
3216 | } | |
3217 | ||
17c76198 PP |
3218 | if (len > INT_MAX) |
3219 | { | |
3220 | DEBUG(D_tls) | |
3221 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
3222 | len); | |
3223 | len = INT_MAX; | |
3224 | } | |
3225 | ||
925ac8e4 JH |
3226 | #ifdef SUPPORT_CORK |
3227 | if (more != corked) | |
3228 | { | |
3229 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
3230 | corked = more; | |
3231 | } | |
3232 | #endif | |
3233 | ||
17c76198 | 3234 | return (int) len; |
059ec3d9 PH |
3235 | } |
3236 | ||
3237 | ||
3238 | ||
17c76198 | 3239 | |
059ec3d9 | 3240 | /************************************************* |
17c76198 | 3241 | * Random number generation * |
059ec3d9 PH |
3242 | *************************************************/ |
3243 | ||
17c76198 PP |
3244 | /* Pseudo-random number generation. The result is not expected to be |
3245 | cryptographically strong but not so weak that someone will shoot themselves | |
3246 | in the foot using it as a nonce in input in some email header scheme or | |
3247 | whatever weirdness they'll twist this into. The result should handle fork() | |
3248 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 3249 | |
17c76198 PP |
3250 | Arguments: |
3251 | max range maximum | |
3252 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
3253 | */ |
3254 | ||
af3498d6 | 3255 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
3256 | int |
3257 | vaguely_random_number(int max) | |
059ec3d9 | 3258 | { |
17c76198 PP |
3259 | unsigned int r; |
3260 | int i, needed_len; | |
17c76198 PP |
3261 | uschar smallbuf[sizeof(r)]; |
3262 | ||
3263 | if (max <= 1) | |
3264 | return 0; | |
3265 | ||
3266 | needed_len = sizeof(r); | |
3267 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
d7978c0f JH |
3268 | asked for a number less than 10. */ |
3269 | ||
17c76198 PP |
3270 | for (r = max, i = 0; r; ++i) |
3271 | r >>= 1; | |
3272 | i = (i + 7) / 8; | |
3273 | if (i < needed_len) | |
3274 | needed_len = i; | |
3275 | ||
3276 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
3277 | if (i < 0) | |
059ec3d9 | 3278 | { |
17c76198 PP |
3279 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
3280 | return vaguely_random_number_fallback(max); | |
3281 | } | |
3282 | r = 0; | |
d7978c0f JH |
3283 | for (uschar * p = smallbuf; needed_len; --needed_len, ++p) |
3284 | r = r * 256 + *p; | |
059ec3d9 | 3285 | |
17c76198 PP |
3286 | /* We don't particularly care about weighted results; if someone wants |
3287 | * smooth distribution and cares enough then they should submit a patch then. */ | |
3288 | return r % max; | |
059ec3d9 | 3289 | } |
af3498d6 PP |
3290 | #else /* HAVE_GNUTLS_RND */ |
3291 | int | |
3292 | vaguely_random_number(int max) | |
3293 | { | |
3294 | return vaguely_random_number_fallback(max); | |
3295 | } | |
3296 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 3297 | |
36f12725 NM |
3298 | |
3299 | ||
3300 | ||
3375e053 PP |
3301 | /************************************************* |
3302 | * Let tls_require_ciphers be checked at startup * | |
3303 | *************************************************/ | |
3304 | ||
3305 | /* The tls_require_ciphers option, if set, must be something which the | |
3306 | library can parse. | |
3307 | ||
3308 | Returns: NULL on success, or error message | |
3309 | */ | |
3310 | ||
3311 | uschar * | |
3312 | tls_validate_require_cipher(void) | |
3313 | { | |
3314 | int rc; | |
3315 | uschar *expciphers = NULL; | |
3316 | gnutls_priority_t priority_cache; | |
3317 | const char *errpos; | |
cf0c6164 | 3318 | uschar * dummy_errstr; |
3375e053 PP |
3319 | |
3320 | #define validate_check_rc(Label) do { \ | |
3321 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
3322 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
3323 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
3324 | ||
3325 | if (exim_gnutls_base_init_done) | |
3326 | log_write(0, LOG_MAIN|LOG_PANIC, | |
3327 | "already initialised GnuTLS, Exim developer bug"); | |
3328 | ||
a5f239e4 | 3329 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 3330 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
3331 | { |
3332 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
3333 | validate_check_rc(US"gnutls_pkcs11_init"); | |
3334 | } | |
3335 | #endif | |
3375e053 PP |
3336 | rc = gnutls_global_init(); |
3337 | validate_check_rc(US"gnutls_global_init()"); | |
3338 | exim_gnutls_base_init_done = TRUE; | |
3339 | ||
3340 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
3341 | return_deinit(NULL); | |
3342 | ||
cf0c6164 JH |
3343 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
3344 | &dummy_errstr)) | |
3375e053 PP |
3345 | return_deinit(US"failed to expand tls_require_ciphers"); |
3346 | ||
3347 | if (!(expciphers && *expciphers)) | |
3348 | return_deinit(NULL); | |
3349 | ||
3350 | DEBUG(D_tls) | |
3351 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
3352 | ||
3353 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
3354 | validate_check_rc(string_sprintf( | |
3355 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
3356 | expciphers, errpos - CS expciphers, errpos)); | |
3357 | ||
3358 | #undef return_deinit | |
3359 | #undef validate_check_rc | |
3360 | gnutls_global_deinit(); | |
3361 | ||
3362 | return NULL; | |
3363 | } | |
3364 | ||
3365 | ||
3366 | ||
3367 | ||
36f12725 NM |
3368 | /************************************************* |
3369 | * Report the library versions. * | |
3370 | *************************************************/ | |
3371 | ||
3372 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
3373 | ||
3374 | Arguments: a FILE* to print the results to | |
3375 | Returns: nothing | |
3376 | */ | |
3377 | ||
3378 | void | |
3379 | tls_version_report(FILE *f) | |
3380 | { | |
754a0503 PP |
3381 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
3382 | " Runtime: %s\n", | |
3383 | LIBGNUTLS_VERSION, | |
3384 | gnutls_check_version(NULL)); | |
36f12725 NM |
3385 | } |
3386 | ||
b10c87b3 | 3387 | #endif /*!MACRO_PREDEF*/ |
2b4a568d JH |
3388 | /* vi: aw ai sw=2 |
3389 | */ | |
059ec3d9 | 3390 | /* End of tls-gnu.c */ |