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 | |
f2de3a33 | 92 | #ifndef DISABLE_OCSP |
2b4a568d JH |
93 | # include <gnutls/ocsp.h> |
94 | #endif | |
899b8bbc JH |
95 | #ifdef SUPPORT_DANE |
96 | # include <gnutls/dane.h> | |
97 | #endif | |
059ec3d9 | 98 | |
f1be21cf JH |
99 | #include "tls-cipher-stdname.c" |
100 | ||
101 | ||
17c76198 | 102 | /* GnuTLS 2 vs 3 |
059ec3d9 | 103 | |
17c76198 PP |
104 | GnuTLS 3 only: |
105 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 106 | |
17c76198 PP |
107 | Changes: |
108 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
109 | */ | |
059ec3d9 | 110 | |
17c76198 | 111 | /* Local static variables for GnuTLS */ |
059ec3d9 | 112 | |
17c76198 | 113 | /* Values for verify_requirement */ |
059ec3d9 | 114 | |
e51c7be2 | 115 | enum peer_verify_requirement |
899b8bbc | 116 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED, VERIFY_DANE }; |
059ec3d9 | 117 | |
17c76198 PP |
118 | /* This holds most state for server or client; with this, we can set up an |
119 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
120 | over the TLS variables available for expansion. | |
059ec3d9 | 121 | |
17c76198 PP |
122 | Some of these correspond to variables in globals.c; those variables will |
123 | be set to point to content in one of these instances, as appropriate for | |
124 | the stage of the process lifetime. | |
059ec3d9 | 125 | |
389ca47a | 126 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 127 | */ |
059ec3d9 | 128 | |
17c76198 | 129 | typedef struct exim_gnutls_state { |
9d1c15ef | 130 | gnutls_session_t session; |
17c76198 | 131 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 132 | gnutls_priority_t priority_cache; |
17c76198 | 133 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
134 | int fd_in; |
135 | int fd_out; | |
136 | BOOL peer_cert_verified; | |
899b8bbc | 137 | BOOL peer_dane_verified; |
9d1c15ef JH |
138 | BOOL trigger_sni_changes; |
139 | BOOL have_set_peerdn; | |
5fd28bb8 | 140 | const struct host_item *host; /* NULL if server */ |
afdb5e9c | 141 | gnutls_x509_crt_t peercert; |
9d1c15ef JH |
142 | uschar *peerdn; |
143 | uschar *ciphersuite; | |
144 | uschar *received_sni; | |
17c76198 PP |
145 | |
146 | const uschar *tls_certificate; | |
147 | const uschar *tls_privatekey; | |
148 | const uschar *tls_sni; /* client send only, not received */ | |
149 | const uschar *tls_verify_certificates; | |
150 | const uschar *tls_crl; | |
151 | const uschar *tls_require_ciphers; | |
e51c7be2 | 152 | |
17c76198 PP |
153 | uschar *exp_tls_certificate; |
154 | uschar *exp_tls_privatekey; | |
17c76198 PP |
155 | uschar *exp_tls_verify_certificates; |
156 | uschar *exp_tls_crl; | |
157 | uschar *exp_tls_require_ciphers; | |
55414b25 | 158 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 159 | #ifndef DISABLE_EVENT |
a7538db1 JH |
160 | uschar *event_action; |
161 | #endif | |
899b8bbc JH |
162 | #ifdef SUPPORT_DANE |
163 | char * const * dane_data; | |
164 | const int * dane_data_len; | |
165 | #endif | |
17c76198 | 166 | |
389ca47a | 167 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 168 | |
17c76198 PP |
169 | uschar *xfer_buffer; |
170 | int xfer_buffer_lwm; | |
171 | int xfer_buffer_hwm; | |
8b77d27a JH |
172 | BOOL xfer_eof; /*XXX never gets set! */ |
173 | BOOL xfer_error; | |
17c76198 PP |
174 | } exim_gnutls_state_st; |
175 | ||
176 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
f2ed27cf JH |
177 | .session = NULL, |
178 | .x509_cred = NULL, | |
179 | .priority_cache = NULL, | |
180 | .verify_requirement = VERIFY_NONE, | |
181 | .fd_in = -1, | |
182 | .fd_out = -1, | |
183 | .peer_cert_verified = FALSE, | |
899b8bbc | 184 | .peer_dane_verified = FALSE, |
f2ed27cf JH |
185 | .trigger_sni_changes =FALSE, |
186 | .have_set_peerdn = FALSE, | |
187 | .host = NULL, | |
188 | .peercert = NULL, | |
189 | .peerdn = NULL, | |
190 | .ciphersuite = NULL, | |
191 | .received_sni = NULL, | |
192 | ||
193 | .tls_certificate = NULL, | |
194 | .tls_privatekey = NULL, | |
195 | .tls_sni = NULL, | |
196 | .tls_verify_certificates = NULL, | |
197 | .tls_crl = NULL, | |
198 | .tls_require_ciphers =NULL, | |
199 | ||
200 | .exp_tls_certificate = NULL, | |
201 | .exp_tls_privatekey = NULL, | |
202 | .exp_tls_verify_certificates = NULL, | |
203 | .exp_tls_crl = NULL, | |
204 | .exp_tls_require_ciphers = NULL, | |
f2ed27cf | 205 | .exp_tls_verify_cert_hostnames = NULL, |
0cbf2b82 | 206 | #ifndef DISABLE_EVENT |
f2ed27cf | 207 | .event_action = NULL, |
e51c7be2 | 208 | #endif |
f2ed27cf JH |
209 | .tlsp = NULL, |
210 | ||
211 | .xfer_buffer = NULL, | |
212 | .xfer_buffer_lwm = 0, | |
213 | .xfer_buffer_hwm = 0, | |
8b77d27a JH |
214 | .xfer_eof = FALSE, |
215 | .xfer_error = FALSE, | |
17c76198 | 216 | }; |
83da1223 | 217 | |
17c76198 PP |
218 | /* Not only do we have our own APIs which don't pass around state, assuming |
219 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
220 | for callbacks, or as part of the session, so we have to keep a "this is the | |
221 | context we're currently dealing with" pointer and rely upon being | |
222 | single-threaded to keep from processing data on an inbound TLS connection while | |
223 | talking to another TLS connection for an outbound check. This does mean that | |
224 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
225 | second connection. |
226 | XXX But see gnutls_session_get_ptr() | |
227 | */ | |
059ec3d9 | 228 | |
74f1a423 | 229 | static exim_gnutls_state_st state_server; |
059ec3d9 | 230 | |
17c76198 PP |
231 | /* dh_params are initialised once within the lifetime of a process using TLS; |
232 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
233 | don't want to repeat this. */ | |
83da1223 | 234 | |
17c76198 | 235 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 236 | |
17c76198 | 237 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 238 | |
17c76198 | 239 | static const int ssl_session_timeout = 200; |
059ec3d9 | 240 | |
fc243e94 | 241 | static const uschar * const exim_default_gnutls_priority = US"NORMAL"; |
83da1223 | 242 | |
17c76198 | 243 | /* Guard library core initialisation */ |
83da1223 | 244 | |
17c76198 | 245 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 246 | |
4fb7df6d | 247 | #ifndef DISABLE_OCSP |
9196d5bf | 248 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 249 | #endif |
9196d5bf | 250 | |
059ec3d9 | 251 | |
17c76198 PP |
252 | /* ------------------------------------------------------------------------ */ |
253 | /* macros */ | |
83da1223 | 254 | |
17c76198 | 255 | #define MAX_HOST_LEN 255 |
83da1223 | 256 | |
17c76198 PP |
257 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
258 | the library logging; a value less than 0 disables the calls to set up logging | |
dc6d1769 JH |
259 | callbacks. GNuTLS also looks for an environment variable - except not for |
260 | setuid binaries, making it useless - "GNUTLS_DEBUG_LEVEL". | |
261 | Allegedly the testscript line "GNUTLS_DEBUG_LEVEL=9 sudo exim ..." would work, | |
262 | but the env var must be added to /etc/sudoers too. */ | |
2c17bb02 | 263 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 264 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 265 | #endif |
83da1223 | 266 | |
2c17bb02 | 267 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 268 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 269 | #endif |
83da1223 | 270 | |
af3498d6 PP |
271 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
272 | can ask for a bit-strength. Without that, we stick to the constant we had | |
273 | before, for now. */ | |
2c17bb02 | 274 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 275 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 276 | #endif |
af3498d6 | 277 | |
cf0c6164 JH |
278 | #define expand_check_tlsvar(Varname, errstr) \ |
279 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 280 | |
17c76198 | 281 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
282 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
283 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
284 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
285 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
286 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
287 | * isn't available sometimes, so this needs to become a conditional | |
288 | * compilation; the sanest way to deal with this being a problem on | |
289 | * older OSes is to block it in the Local/Makefile with this compiler | |
290 | * definition */ | |
e51c7be2 JH |
291 | # ifndef AVOID_GNUTLS_PKCS11 |
292 | # define HAVE_GNUTLS_PKCS11 | |
293 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 294 | #endif |
83da1223 | 295 | |
af3498d6 PP |
296 | |
297 | ||
298 | ||
299 | /* ------------------------------------------------------------------------ */ | |
300 | /* Callback declarations */ | |
301 | ||
302 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
303 | static void exim_gnutls_logger_cb(int level, const char *message); | |
304 | #endif | |
305 | ||
306 | static int exim_sni_handling_cb(gnutls_session_t session); | |
307 | ||
f2de3a33 | 308 | #ifndef DISABLE_OCSP |
44662487 JH |
309 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
310 | gnutls_datum_t * ocsp_response); | |
311 | #endif | |
af3498d6 PP |
312 | |
313 | ||
314 | ||
17c76198 PP |
315 | /* ------------------------------------------------------------------------ */ |
316 | /* Static functions */ | |
059ec3d9 PH |
317 | |
318 | /************************************************* | |
319 | * Handle TLS error * | |
320 | *************************************************/ | |
321 | ||
322 | /* Called from lots of places when errors occur before actually starting to do | |
323 | the TLS handshake, that is, while the session is still in clear. Always returns | |
324 | DEFER for a server and FAIL for a client so that most calls can use "return | |
325 | tls_error(...)" to do this processing and then give an appropriate return. A | |
326 | single function is used for both server and client, because it is called from | |
327 | some shared functions. | |
328 | ||
329 | Argument: | |
330 | prefix text to include in the logged error | |
7199e1ee TF |
331 | msg additional error string (may be NULL) |
332 | usually obtained from gnutls_strerror() | |
17c76198 PP |
333 | host NULL if setting up a server; |
334 | the connected host if setting up a client | |
cf0c6164 | 335 | errstr pointer to returned error string |
059ec3d9 PH |
336 | |
337 | Returns: OK/DEFER/FAIL | |
338 | */ | |
339 | ||
340 | static int | |
48224640 | 341 | tls_error(const uschar *prefix, const uschar *msg, const host_item *host, |
cf0c6164 | 342 | uschar ** errstr) |
059ec3d9 | 343 | { |
cf0c6164 | 344 | if (errstr) |
48224640 | 345 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : US""); |
cf0c6164 | 346 | return host ? FAIL : DEFER; |
059ec3d9 PH |
347 | } |
348 | ||
349 | ||
452a164f JH |
350 | static int |
351 | tls_error_gnu(const uschar *prefix, int err, const host_item *host, | |
352 | uschar ** errstr) | |
353 | { | |
354 | return tls_error(prefix, US gnutls_strerror(err), host, errstr); | |
355 | } | |
356 | ||
357 | static int | |
358 | tls_error_sys(const uschar *prefix, int err, const host_item *host, | |
359 | uschar ** errstr) | |
360 | { | |
361 | return tls_error(prefix, US strerror(err), host, errstr); | |
362 | } | |
059ec3d9 | 363 | |
17c76198 | 364 | |
059ec3d9 | 365 | /************************************************* |
17c76198 | 366 | * Deal with logging errors during I/O * |
059ec3d9 PH |
367 | *************************************************/ |
368 | ||
17c76198 | 369 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 370 | |
17c76198 PP |
371 | Argument: |
372 | state the current GnuTLS exim state container | |
373 | rc the GnuTLS error code, or 0 if it's a local error | |
374 | when text identifying read or write | |
95f52235 | 375 | text local error text when rc is 0 |
059ec3d9 | 376 | |
17c76198 | 377 | Returns: nothing |
059ec3d9 PH |
378 | */ |
379 | ||
17c76198 PP |
380 | static void |
381 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 382 | { |
48224640 | 383 | const uschar * msg; |
cf0c6164 | 384 | uschar * errstr; |
059ec3d9 | 385 | |
17c76198 | 386 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
95f52235 | 387 | msg = string_sprintf("A TLS fatal alert has been received: %s", |
17c76198 PP |
388 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); |
389 | else | |
48224640 | 390 | msg = US gnutls_strerror(rc); |
059ec3d9 | 391 | |
cf0c6164 JH |
392 | (void) tls_error(when, msg, state->host, &errstr); |
393 | ||
394 | if (state->host) | |
395 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
396 | state->host->name, state->host->address, errstr); | |
397 | else | |
398 | { | |
399 | uschar * conn_info = smtp_get_connection_info(); | |
400 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
401 | /* I'd like to get separated H= here, but too hard for now */ | |
402 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
403 | } | |
17c76198 | 404 | } |
059ec3d9 | 405 | |
059ec3d9 | 406 | |
059ec3d9 | 407 | |
059ec3d9 | 408 | |
17c76198 PP |
409 | /************************************************* |
410 | * Set various Exim expansion vars * | |
411 | *************************************************/ | |
059ec3d9 | 412 | |
e51c7be2 JH |
413 | #define exim_gnutls_cert_err(Label) \ |
414 | do \ | |
415 | { \ | |
416 | if (rc != GNUTLS_E_SUCCESS) \ | |
417 | { \ | |
418 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
419 | (Label), gnutls_strerror(rc)); \ | |
420 | return rc; \ | |
421 | } \ | |
422 | } while (0) | |
9d1c15ef JH |
423 | |
424 | static int | |
27f19eb4 | 425 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
426 | { |
427 | int rc; | |
428 | ||
429 | rc = gnutls_x509_crt_init(crtp); | |
430 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
431 | ||
432 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
433 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
434 | ||
435 | return rc; | |
436 | } | |
437 | ||
438 | #undef exim_gnutls_cert_err | |
439 | ||
440 | ||
17c76198 PP |
441 | /* We set various Exim global variables from the state, once a session has |
442 | been established. With TLS callouts, may need to change this to stack | |
443 | variables, or just re-call it with the server state after client callout | |
444 | has finished. | |
059ec3d9 | 445 | |
9d1c15ef | 446 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
447 | |
448 | Sets: | |
449 | tls_active fd | |
450 | tls_bits strength indicator | |
451 | tls_certificate_verified bool indicator | |
452 | tls_channelbinding_b64 for some SASL mechanisms | |
453 | tls_cipher a string | |
9d1c15ef | 454 | tls_peercert pointer to library internal |
17c76198 PP |
455 | tls_peerdn a string |
456 | tls_sni a (UTF-8) string | |
9d1c15ef | 457 | tls_ourcert pointer to library internal |
17c76198 PP |
458 | |
459 | Argument: | |
460 | state the relevant exim_gnutls_state_st * | |
461 | */ | |
462 | ||
463 | static void | |
9d1c15ef | 464 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 465 | { |
17c76198 | 466 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
467 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
468 | int old_pool; | |
469 | int rc; | |
470 | gnutls_datum_t channel; | |
471 | #endif | |
9d1c15ef | 472 | tls_support * tlsp = state->tlsp; |
17c76198 | 473 | |
74f1a423 JH |
474 | tlsp->active.sock = state->fd_out; |
475 | tlsp->active.tls_ctx = state; | |
17c76198 PP |
476 | |
477 | cipher = gnutls_cipher_get(state->session); | |
478 | /* returns size in "bytes" */ | |
9d1c15ef | 479 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 480 | |
9d1c15ef | 481 | tlsp->cipher = state->ciphersuite; |
17c76198 | 482 | |
817d9f57 | 483 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 484 | |
9d1c15ef | 485 | tlsp->certificate_verified = state->peer_cert_verified; |
899b8bbc JH |
486 | #ifdef SUPPORT_DANE |
487 | tlsp->dane_verified = state->peer_dane_verified; | |
488 | #endif | |
059ec3d9 | 489 | |
17c76198 PP |
490 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
491 | only available for use for authenticators while this TLS session is running. */ | |
492 | ||
493 | tls_channelbinding_b64 = NULL; | |
494 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
495 | channel.data = NULL; | |
496 | channel.size = 0; | |
1f20760b JH |
497 | if ((rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel))) |
498 | { DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); } | |
499 | else | |
500 | { | |
17c76198 PP |
501 | old_pool = store_pool; |
502 | store_pool = POOL_PERM; | |
1f20760b | 503 | tls_channelbinding_b64 = b64encode(CUS channel.data, (int)channel.size); |
17c76198 PP |
504 | store_pool = old_pool; |
505 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
1f20760b | 506 | } |
17c76198 PP |
507 | #endif |
508 | ||
9d1c15ef JH |
509 | /* peercert is set in peer_status() */ |
510 | tlsp->peerdn = state->peerdn; | |
511 | tlsp->sni = state->received_sni; | |
512 | ||
513 | /* record our certificate */ | |
514 | { | |
27f19eb4 | 515 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
516 | gnutls_x509_crt_t crt; |
517 | ||
518 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
519 | } | |
059ec3d9 PH |
520 | } |
521 | ||
522 | ||
523 | ||
17c76198 | 524 | |
059ec3d9 | 525 | /************************************************* |
575643cd | 526 | * Setup up DH parameters * |
059ec3d9 PH |
527 | *************************************************/ |
528 | ||
575643cd | 529 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
530 | be re-generated every so often, depending on security policy. What we do is to |
531 | keep these parameters in a file in the spool directory. If the file does not | |
532 | exist, we generate them. This means that it is easy to cause a regeneration. | |
533 | ||
534 | The new file is written as a temporary file and renamed, so that an incomplete | |
535 | file is never present. If two processes both compute some new parameters, you | |
536 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
537 | prevent this. | |
538 | ||
059ec3d9 PH |
539 | Returns: OK/DEFER/FAIL |
540 | */ | |
541 | ||
542 | static int | |
cf0c6164 | 543 | init_server_dh(uschar ** errstr) |
059ec3d9 | 544 | { |
17c76198 PP |
545 | int fd, rc; |
546 | unsigned int dh_bits; | |
27f19eb4 | 547 | gnutls_datum_t m; |
a799883d PP |
548 | uschar filename_buf[PATH_MAX]; |
549 | uschar *filename = NULL; | |
17c76198 | 550 | size_t sz; |
a799883d PP |
551 | uschar *exp_tls_dhparam; |
552 | BOOL use_file_in_spool = FALSE; | |
17c76198 | 553 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 554 | |
17c76198 | 555 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 556 | |
452a164f JH |
557 | if ((rc = gnutls_dh_params_init(&dh_server_params))) |
558 | return tls_error_gnu(US"gnutls_dh_params_init", rc, host, errstr); | |
059ec3d9 | 559 | |
a799883d PP |
560 | m.data = NULL; |
561 | m.size = 0; | |
562 | ||
cf0c6164 | 563 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
564 | return DEFER; |
565 | ||
566 | if (!exp_tls_dhparam) | |
567 | { | |
568 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
569 | m.data = US std_dh_prime_default(); | |
570 | m.size = Ustrlen(m.data); | |
571 | } | |
572 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
573 | use_file_in_spool = TRUE; | |
574 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
575 | { | |
576 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
577 | return OK; | |
578 | } | |
579 | else if (exp_tls_dhparam[0] != '/') | |
580 | { | |
f5d25c2b | 581 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
48224640 | 582 | return tls_error(US"No standard prime named", exp_tls_dhparam, NULL, errstr); |
a799883d PP |
583 | m.size = Ustrlen(m.data); |
584 | } | |
585 | else | |
a799883d | 586 | filename = exp_tls_dhparam; |
a799883d PP |
587 | |
588 | if (m.data) | |
589 | { | |
452a164f JH |
590 | if ((rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM))) |
591 | return tls_error_gnu(US"gnutls_dh_params_import_pkcs3", rc, host, errstr); | |
a799883d PP |
592 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); |
593 | return OK; | |
594 | } | |
595 | ||
af3498d6 PP |
596 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
597 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 | 598 | different filename and ensure we have sufficient bits. */ |
452a164f JH |
599 | |
600 | if (!(dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL))) | |
cf0c6164 | 601 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 602 | DEBUG(D_tls) |
b34fc30c | 603 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
604 | dh_bits); |
605 | #else | |
606 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
607 | DEBUG(D_tls) | |
608 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
609 | dh_bits); | |
610 | #endif | |
059ec3d9 | 611 | |
3375e053 PP |
612 | /* Some clients have hard-coded limits. */ |
613 | if (dh_bits > tls_dh_max_bits) | |
614 | { | |
615 | DEBUG(D_tls) | |
616 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
617 | tls_dh_max_bits); | |
618 | dh_bits = tls_dh_max_bits; | |
619 | } | |
620 | ||
a799883d PP |
621 | if (use_file_in_spool) |
622 | { | |
623 | if (!string_format(filename_buf, sizeof(filename_buf), | |
624 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 625 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
626 | filename = filename_buf; |
627 | } | |
059ec3d9 | 628 | |
b5aea5e1 | 629 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 630 | parameters. */ |
059ec3d9 | 631 | |
f5d25c2b | 632 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 633 | { |
b5aea5e1 | 634 | struct stat statbuf; |
17c76198 PP |
635 | FILE *fp; |
636 | int saved_errno; | |
637 | ||
638 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
639 | { | |
640 | saved_errno = errno; | |
641 | (void)close(fd); | |
452a164f | 642 | return tls_error_sys(US"TLS cache stat failed", saved_errno, NULL, errstr); |
17c76198 PP |
643 | } |
644 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
645 | { |
646 | (void)close(fd); | |
cf0c6164 | 647 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 648 | } |
40c90bca | 649 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
650 | { |
651 | saved_errno = errno; | |
652 | (void)close(fd); | |
452a164f JH |
653 | return tls_error_sys(US"fdopen(TLS cache stat fd) failed", |
654 | saved_errno, NULL, errstr); | |
b5aea5e1 | 655 | } |
059ec3d9 | 656 | |
b5aea5e1 | 657 | m.size = statbuf.st_size; |
40c90bca | 658 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
659 | { |
660 | fclose(fp); | |
452a164f | 661 | return tls_error_sys(US"malloc failed", errno, NULL, errstr); |
17c76198 | 662 | } |
40c90bca | 663 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
664 | { |
665 | saved_errno = errno; | |
666 | fclose(fp); | |
667 | free(m.data); | |
452a164f | 668 | return tls_error_sys(US"fread failed", saved_errno, NULL, errstr); |
17c76198 PP |
669 | } |
670 | fclose(fp); | |
b5aea5e1 | 671 | |
17c76198 | 672 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 673 | free(m.data); |
452a164f JH |
674 | if (rc) |
675 | return tls_error_gnu(US"gnutls_dh_params_import_pkcs3", rc, host, errstr); | |
17c76198 | 676 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); |
b5aea5e1 PH |
677 | } |
678 | ||
679 | /* If the file does not exist, fall through to compute new data and cache it. | |
680 | If there was any other opening error, it is serious. */ | |
681 | ||
182ad5cf PH |
682 | else if (errno == ENOENT) |
683 | { | |
17c76198 | 684 | rc = -1; |
182ad5cf | 685 | DEBUG(D_tls) |
17c76198 | 686 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
687 | } |
688 | else | |
17c76198 | 689 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 690 | NULL, NULL, errstr); |
b5aea5e1 PH |
691 | |
692 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
693 | is not useful. One particular case of this is when upgrading from an older | |
694 | release of Exim in which the data was stored in a different format. We don't | |
695 | try to be clever and support both formats; we just regenerate new data in this | |
696 | case. */ | |
697 | ||
17c76198 | 698 | if (rc < 0) |
b5aea5e1 | 699 | { |
17c76198 | 700 | uschar *temp_fn; |
201f5254 | 701 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 702 | |
17c76198 PP |
703 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
704 | return tls_error(US"Filename too long to generate replacement", | |
48224640 | 705 | filename, NULL, errstr); |
059ec3d9 | 706 | |
48224640 | 707 | temp_fn = string_copy(US"%s.XXXXXXX"); |
f5d25c2b | 708 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
452a164f | 709 | return tls_error_sys(US"Unable to open temp file", errno, NULL, errstr); |
b66fecb4 | 710 | (void)exim_chown(temp_fn, exim_uid, exim_gid); /* Probably not necessary */ |
059ec3d9 | 711 | |
201f5254 PP |
712 | /* GnuTLS overshoots! |
713 | * If we ask for 2236, we might get 2237 or more. | |
714 | * But there's no way to ask GnuTLS how many bits there really are. | |
715 | * We can ask how many bits were used in a TLS session, but that's it! | |
716 | * The prime itself is hidden behind too much abstraction. | |
717 | * So we ask for less, and proceed on a wing and a prayer. | |
718 | * First attempt, subtracted 3 for 2233 and got 2240. | |
719 | */ | |
cae6e576 | 720 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
721 | { |
722 | dh_bits_gen = dh_bits - 10; | |
723 | DEBUG(D_tls) | |
724 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
725 | dh_bits_gen); | |
726 | } | |
727 | ||
728 | DEBUG(D_tls) | |
729 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
730 | dh_bits_gen); | |
452a164f JH |
731 | if ((rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen))) |
732 | return tls_error_gnu(US"gnutls_dh_params_generate2", rc, host, errstr); | |
17c76198 PP |
733 | |
734 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
735 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
736 | sample apps handle this. */ | |
737 | ||
738 | sz = 0; | |
739 | m.data = NULL; | |
452a164f JH |
740 | if ( (rc = gnutls_dh_params_export_pkcs3(dh_server_params, |
741 | GNUTLS_X509_FMT_PEM, m.data, &sz)) | |
742 | && rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
743 | return tls_error_gnu(US"gnutls_dh_params_export_pkcs3(NULL) sizing", | |
744 | rc, host, errstr); | |
17c76198 | 745 | m.size = sz; |
40c90bca | 746 | if (!(m.data = malloc(m.size))) |
452a164f | 747 | return tls_error_sys(US"memory allocation failed", errno, NULL, errstr); |
40c90bca | 748 | |
1f00591e | 749 | /* this will return a size 1 less than the allocation size above */ |
452a164f JH |
750 | if ((rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
751 | m.data, &sz))) | |
17c76198 PP |
752 | { |
753 | free(m.data); | |
452a164f | 754 | return tls_error_gnu(US"gnutls_dh_params_export_pkcs3() real", rc, host, errstr); |
17c76198 | 755 | } |
1f00591e | 756 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 757 | |
f5d25c2b | 758 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 PP |
759 | { |
760 | free(m.data); | |
452a164f JH |
761 | return tls_error_sys(US"TLS cache write D-H params failed", |
762 | errno, NULL, errstr); | |
17c76198 | 763 | } |
b5aea5e1 | 764 | free(m.data); |
f5d25c2b | 765 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
452a164f JH |
766 | return tls_error_sys(US"TLS cache write D-H params final newline failed", |
767 | errno, NULL, errstr); | |
17c76198 | 768 | |
f5d25c2b | 769 | if ((rc = close(fd))) |
452a164f | 770 | return tls_error_sys(US"TLS cache write close() failed", errno, NULL, errstr); |
059ec3d9 | 771 | |
17c76198 | 772 | if (Urename(temp_fn, filename) < 0) |
452a164f JH |
773 | return tls_error_sys(string_sprintf("failed to rename \"%s\" as \"%s\"", |
774 | temp_fn, filename), errno, NULL, errstr); | |
059ec3d9 | 775 | |
17c76198 | 776 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
777 | } |
778 | ||
17c76198 | 779 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
780 | return OK; |
781 | } | |
782 | ||
783 | ||
784 | ||
785 | ||
23bb6982 JH |
786 | /* Create and install a selfsigned certificate, for use in server mode */ |
787 | ||
788 | static int | |
cf0c6164 | 789 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
790 | { |
791 | gnutls_x509_crt_t cert = NULL; | |
792 | time_t now; | |
793 | gnutls_x509_privkey_t pkey = NULL; | |
794 | const uschar * where; | |
795 | int rc; | |
796 | ||
797 | where = US"initialising pkey"; | |
798 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
799 | ||
800 | where = US"initialising cert"; | |
801 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
802 | ||
803 | where = US"generating pkey"; | |
804 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 805 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
4312da48 JH |
806 | # ifndef GNUTLS_SEC_PARAM_MEDIUM |
807 | # define GNUTLS_SEC_PARAM_MEDIUM GNUTLS_SEC_PARAM_HIGH | |
808 | # endif | |
6aac3239 | 809 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_MEDIUM), |
76075bb5 | 810 | #else |
6aac3239 | 811 | 2048, |
76075bb5 JH |
812 | #endif |
813 | 0))) | |
23bb6982 JH |
814 | goto err; |
815 | ||
816 | where = US"configuring cert"; | |
1613fd68 | 817 | now = 1; |
23bb6982 JH |
818 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) |
819 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
820 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
821 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
822 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
823 | ||
824 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
825 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
826 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
827 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
828 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
829 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
830 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
831 | ) | |
832 | goto err; | |
833 | ||
834 | where = US"signing cert"; | |
835 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
836 | ||
837 | where = US"installing selfsign cert"; | |
838 | /* Since: 2.4.0 */ | |
839 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
840 | goto err; | |
841 | ||
842 | rc = OK; | |
843 | ||
844 | out: | |
845 | if (cert) gnutls_x509_crt_deinit(cert); | |
846 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
847 | return rc; | |
848 | ||
849 | err: | |
452a164f | 850 | rc = tls_error_gnu(where, rc, NULL, errstr); |
23bb6982 JH |
851 | goto out; |
852 | } | |
853 | ||
854 | ||
855 | ||
856 | ||
47195144 JH |
857 | /* Add certificate and key, from files. |
858 | ||
859 | Return: | |
860 | Zero or negative: good. Negate value for certificate index if < 0. | |
861 | Greater than zero: FAIL or DEFER code. | |
862 | */ | |
863 | ||
ba86e143 JH |
864 | static int |
865 | tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, | |
866 | uschar * certfile, uschar * keyfile, uschar ** errstr) | |
867 | { | |
868 | int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, | |
869 | CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); | |
47195144 | 870 | if (rc < 0) |
452a164f | 871 | return tls_error_gnu( |
47195144 | 872 | string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile), |
452a164f | 873 | rc, host, errstr); |
47195144 | 874 | return -rc; |
ba86e143 JH |
875 | } |
876 | ||
877 | ||
059ec3d9 | 878 | /************************************************* |
17c76198 | 879 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
880 | *************************************************/ |
881 | ||
17c76198 PP |
882 | /* Called from both server and client code, via tls_init(), and also from |
883 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
884 | ||
885 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
886 | ||
887 | The callback should not call us unless state->trigger_sni_changes is true, | |
888 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
889 | |
890 | Arguments: | |
17c76198 | 891 | state exim_gnutls_state_st * |
cf0c6164 | 892 | errstr error string pointer |
059ec3d9 PH |
893 | |
894 | Returns: OK/DEFER/FAIL | |
895 | */ | |
896 | ||
897 | static int | |
ba86e143 | 898 | tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 899 | { |
1365611d | 900 | struct stat statbuf; |
059ec3d9 | 901 | int rc; |
17c76198 PP |
902 | const host_item *host = state->host; /* macro should be reconsidered? */ |
903 | uschar *saved_tls_certificate = NULL; | |
904 | uschar *saved_tls_privatekey = NULL; | |
905 | uschar *saved_tls_verify_certificates = NULL; | |
906 | uschar *saved_tls_crl = NULL; | |
907 | int cert_count; | |
908 | ||
909 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 910 | if (!host) /* server */ |
17c76198 PP |
911 | if (!state->received_sni) |
912 | { | |
ba86e143 JH |
913 | if ( state->tls_certificate |
914 | && ( Ustrstr(state->tls_certificate, US"tls_sni") | |
915 | || Ustrstr(state->tls_certificate, US"tls_in_sni") | |
916 | || Ustrstr(state->tls_certificate, US"tls_out_sni") | |
917 | ) ) | |
17c76198 PP |
918 | { |
919 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
920 | state->trigger_sni_changes = TRUE; | |
921 | } | |
922 | } | |
923 | else | |
924 | { | |
1365611d | 925 | /* useful for debugging */ |
17c76198 PP |
926 | saved_tls_certificate = state->exp_tls_certificate; |
927 | saved_tls_privatekey = state->exp_tls_privatekey; | |
928 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
929 | saved_tls_crl = state->exp_tls_crl; | |
930 | } | |
059ec3d9 | 931 | |
452a164f JH |
932 | if ((rc = gnutls_certificate_allocate_credentials(&state->x509_cred))) |
933 | return tls_error_gnu(US"gnutls_certificate_allocate_credentials", | |
934 | rc, host, errstr); | |
47195144 JH |
935 | |
936 | #ifdef SUPPORT_SRV_OCSP_STACK | |
937 | gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2); | |
938 | #endif | |
1365611d | 939 | |
17c76198 PP |
940 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
941 | state members, assuming consistent naming; and expand_check() returns | |
942 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 943 | |
17c76198 PP |
944 | /* check if we at least have a certificate, before doing expensive |
945 | D-H generation. */ | |
059ec3d9 | 946 | |
cf0c6164 | 947 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 948 | return DEFER; |
059ec3d9 | 949 | |
17c76198 | 950 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 951 | |
23bb6982 JH |
952 | if ( !state->exp_tls_certificate |
953 | || !*state->exp_tls_certificate | |
954 | ) | |
2b4a568d | 955 | if (!host) |
cf0c6164 | 956 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
957 | else |
958 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 959 | |
cf0c6164 | 960 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
961 | return DEFER; |
962 | ||
17c76198 PP |
963 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
964 | ||
965 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 966 | { |
17c76198 PP |
967 | state->tls_privatekey = state->tls_certificate; |
968 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 969 | } |
c91535f3 | 970 | |
059ec3d9 | 971 | |
17c76198 | 972 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
973 | { |
974 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
975 | state->exp_tls_certificate, state->exp_tls_privatekey); |
976 | ||
977 | if (state->received_sni) | |
23bb6982 JH |
978 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
979 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
980 | ) | |
17c76198 | 981 | { |
b34fc30c | 982 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
983 | } |
984 | else | |
985 | { | |
b34fc30c | 986 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 987 | } |
059ec3d9 | 988 | |
ba86e143 JH |
989 | if (!host) /* server */ |
990 | { | |
991 | const uschar * clist = state->exp_tls_certificate; | |
992 | const uschar * klist = state->exp_tls_privatekey; | |
47195144 JH |
993 | const uschar * olist; |
994 | int csep = 0, ksep = 0, osep = 0, cnt = 0; | |
995 | uschar * cfile, * kfile, * ofile; | |
996 | ||
997 | #ifndef DISABLE_OCSP | |
998 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr)) | |
999 | return DEFER; | |
1000 | olist = ofile; | |
1001 | #endif | |
ba86e143 JH |
1002 | |
1003 | while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) | |
47195144 | 1004 | |
ba86e143 JH |
1005 | if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) |
1006 | return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); | |
47195144 | 1007 | else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr))) |
ba86e143 JH |
1008 | return rc; |
1009 | else | |
47195144 JH |
1010 | { |
1011 | int gnutls_cert_index = -rc; | |
ba86e143 | 1012 | DEBUG(D_tls) debug_printf("TLS: cert/key %s registered\n", cfile); |
47195144 JH |
1013 | |
1014 | /* Set the OCSP stapling server info */ | |
1015 | ||
1016 | #ifndef DISABLE_OCSP | |
1017 | if (tls_ocsp_file) | |
1018 | if (gnutls_buggy_ocsp) | |
1019 | { | |
1020 | DEBUG(D_tls) | |
1021 | debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
1022 | } | |
1023 | else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) | |
1024 | { | |
1025 | /* Use the full callback method for stapling just to get | |
1026 | observability. More efficient would be to read the file once only, | |
1027 | if it never changed (due to SNI). Would need restart on file update, | |
1028 | or watch datestamp. */ | |
1029 | ||
1030 | # ifdef SUPPORT_SRV_OCSP_STACK | |
452a164f JH |
1031 | if ((rc = gnutls_certificate_set_ocsp_status_request_function2( |
1032 | state->x509_cred, gnutls_cert_index, | |
1033 | server_ocsp_stapling_cb, ofile))) | |
1034 | return tls_error_gnu( | |
1035 | US"gnutls_certificate_set_ocsp_status_request_function2", | |
1036 | rc, host, errstr); | |
47195144 JH |
1037 | # else |
1038 | if (cnt++ > 0) | |
1039 | { | |
1040 | DEBUG(D_tls) | |
1041 | debug_printf("oops; multiple OCSP files not supported\n"); | |
1042 | break; | |
1043 | } | |
1044 | gnutls_certificate_set_ocsp_status_request_function( | |
1045 | state->x509_cred, server_ocsp_stapling_cb, ofile); | |
1046 | # endif | |
1047 | ||
1048 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); | |
1049 | } | |
1050 | else | |
1051 | DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); | |
1052 | #endif | |
1053 | } | |
ba86e143 JH |
1054 | } |
1055 | else | |
1056 | { | |
47195144 | 1057 | if (0 < (rc = tls_add_certfile(state, host, |
ba86e143 JH |
1058 | state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) |
1059 | return rc; | |
1060 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
1061 | } | |
1062 | ||
b34fc30c | 1063 | } /* tls_certificate */ |
059ec3d9 | 1064 | |
2b4a568d | 1065 | |
059ec3d9 PH |
1066 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
1067 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
1068 | error message is provided. However, if we just refrain from setting anything up | |
1069 | in that case, certificate verification fails, which seems to be the correct | |
1070 | behaviour. */ | |
1071 | ||
610ff438 | 1072 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 1073 | { |
cf0c6164 | 1074 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 1075 | return DEFER; |
610ff438 JH |
1076 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
1077 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1078 | state->exp_tls_verify_certificates = NULL; | |
1079 | #endif | |
17c76198 | 1080 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 1081 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 1082 | return DEFER; |
059ec3d9 | 1083 | |
1365611d PP |
1084 | if (!(state->exp_tls_verify_certificates && |
1085 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
1086 | { |
1087 | DEBUG(D_tls) | |
1365611d PP |
1088 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
1089 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 1090 | return OK; |
b34fc30c | 1091 | } |
1365611d | 1092 | } |
83e2f8a2 PP |
1093 | else |
1094 | { | |
1095 | DEBUG(D_tls) | |
1096 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
1097 | return OK; | |
1098 | } | |
17c76198 | 1099 | |
cb1d7830 JH |
1100 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
1101 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1102 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
1103 | else | |
1104 | #endif | |
1365611d | 1105 | { |
cb1d7830 JH |
1106 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
1107 | { | |
1108 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
1109 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
1110 | strerror(errno)); | |
1111 | return DEFER; | |
1112 | } | |
17c76198 | 1113 | |
a7fec7a7 | 1114 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1115 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1116 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1117 | other weirdness. The thing we really want to check is that it's not a | |
1118 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1119 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1120 | if (S_ISDIR(statbuf.st_mode)) |
1121 | { | |
1122 | DEBUG(D_tls) | |
1123 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1124 | state->exp_tls_verify_certificates); | |
1125 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1126 | "tls_verify_certificates \"%s\" is a directory", | |
1127 | state->exp_tls_verify_certificates); | |
1128 | return DEFER; | |
1129 | } | |
a7fec7a7 | 1130 | #endif |
059ec3d9 | 1131 | |
cb1d7830 JH |
1132 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1133 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1134 | |
cb1d7830 JH |
1135 | if (statbuf.st_size == 0) |
1136 | { | |
1137 | DEBUG(D_tls) | |
1138 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1139 | return OK; | |
1140 | } | |
059ec3d9 | 1141 | |
cb1d7830 | 1142 | cert_count = |
a7fec7a7 JH |
1143 | |
1144 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1145 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1146 | ? | |
1147 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1148 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1149 | : | |
a7fec7a7 | 1150 | #endif |
cb1d7830 JH |
1151 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1152 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1153 | } | |
a7fec7a7 | 1154 | |
1365611d | 1155 | if (cert_count < 0) |
452a164f JH |
1156 | return tls_error_gnu(US"setting certificate trust", cert_count, host, errstr); |
1157 | DEBUG(D_tls) | |
1158 | debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1159 | |
5c8cda3a PP |
1160 | if (state->tls_crl && *state->tls_crl && |
1161 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1162 | { |
5c8cda3a | 1163 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
452a164f JH |
1164 | if ((cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, |
1165 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM)) < 0) | |
1166 | return tls_error_gnu(US"gnutls_certificate_set_x509_crl_file", | |
1167 | cert_count, host, errstr); | |
1168 | ||
5c8cda3a | 1169 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1170 | } |
059ec3d9 | 1171 | |
059ec3d9 PH |
1172 | return OK; |
1173 | } | |
1174 | ||
1175 | ||
1176 | ||
1177 | ||
1365611d PP |
1178 | /************************************************* |
1179 | * Set X.509 state variables * | |
1180 | *************************************************/ | |
1181 | ||
1182 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1183 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1184 | structure. Which means various other non-re-expanded pieces of state | |
1185 | need to be re-set in the new struct, so the setting logic is pulled | |
1186 | out to this. | |
1187 | ||
1188 | Arguments: | |
1189 | state exim_gnutls_state_st * | |
cf0c6164 | 1190 | errstr error string pointer |
1365611d PP |
1191 | |
1192 | Returns: OK/DEFER/FAIL | |
1193 | */ | |
1194 | ||
1195 | static int | |
cf0c6164 | 1196 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1197 | { |
1198 | int rc; | |
1199 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1200 | ||
1201 | /* Create D-H parameters, or read them from the cache file. This function does | |
1202 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1203 | client-side params. */ | |
1204 | ||
1205 | if (!state->host) | |
1206 | { | |
1207 | if (!dh_server_params) | |
452a164f | 1208 | if ((rc = init_server_dh(errstr)) != OK) return rc; |
1365611d PP |
1209 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); |
1210 | } | |
1211 | ||
1212 | /* Link the credentials to the session. */ | |
1213 | ||
452a164f JH |
1214 | if ((rc = gnutls_credentials_set(state->session, |
1215 | GNUTLS_CRD_CERTIFICATE, state->x509_cred))) | |
1216 | return tls_error_gnu(US"gnutls_credentials_set", rc, host, errstr); | |
1365611d PP |
1217 | |
1218 | return OK; | |
1219 | } | |
1220 | ||
059ec3d9 | 1221 | /************************************************* |
17c76198 | 1222 | * Initialize for GnuTLS * |
059ec3d9 PH |
1223 | *************************************************/ |
1224 | ||
9196d5bf | 1225 | |
4fb7df6d JH |
1226 | #ifndef DISABLE_OCSP |
1227 | ||
9196d5bf JH |
1228 | static BOOL |
1229 | tls_is_buggy_ocsp(void) | |
1230 | { | |
1231 | const uschar * s; | |
1232 | uschar maj, mid, mic; | |
1233 | ||
1234 | s = CUS gnutls_check_version(NULL); | |
1235 | maj = atoi(CCS s); | |
1236 | if (maj == 3) | |
1237 | { | |
1238 | while (*s && *s != '.') s++; | |
1239 | mid = atoi(CCS ++s); | |
1240 | if (mid <= 2) | |
1241 | return TRUE; | |
1242 | else if (mid >= 5) | |
1243 | return FALSE; | |
1244 | else | |
1245 | { | |
1246 | while (*s && *s != '.') s++; | |
1247 | mic = atoi(CCS ++s); | |
1248 | return mic <= (mid == 3 ? 16 : 3); | |
1249 | } | |
1250 | } | |
1251 | return FALSE; | |
1252 | } | |
1253 | ||
4fb7df6d | 1254 | #endif |
9196d5bf JH |
1255 | |
1256 | ||
17c76198 PP |
1257 | /* Called from both server and client code. In the case of a server, errors |
1258 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1259 | |
1260 | Arguments: | |
17c76198 PP |
1261 | host connected host, if client; NULL if server |
1262 | certificate certificate file | |
1263 | privatekey private key file | |
1264 | sni TLS SNI to send, sometimes when client; else NULL | |
1265 | cas CA certs file | |
1266 | crl CRL file | |
1267 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1268 | caller_state returned state-info structure |
cf0c6164 | 1269 | errstr error string pointer |
059ec3d9 | 1270 | |
17c76198 | 1271 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1272 | */ |
1273 | ||
17c76198 PP |
1274 | static int |
1275 | tls_init( | |
1276 | const host_item *host, | |
1277 | const uschar *certificate, | |
1278 | const uschar *privatekey, | |
1279 | const uschar *sni, | |
1280 | const uschar *cas, | |
1281 | const uschar *crl, | |
1282 | const uschar *require_ciphers, | |
cf0c6164 | 1283 | exim_gnutls_state_st **caller_state, |
74f1a423 | 1284 | tls_support * tlsp, |
cf0c6164 | 1285 | uschar ** errstr) |
059ec3d9 | 1286 | { |
00c0dd4e | 1287 | exim_gnutls_state_st * state; |
17c76198 PP |
1288 | int rc; |
1289 | size_t sz; | |
00c0dd4e JH |
1290 | const char * errpos; |
1291 | const uschar * p; | |
17c76198 PP |
1292 | |
1293 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1294 | { |
17c76198 PP |
1295 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1296 | ||
a5f239e4 PP |
1297 | #ifdef HAVE_GNUTLS_PKCS11 |
1298 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1299 | which loads modules from a config file, which sounds good and may be wanted | |
1300 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1301 | environment variables are used and so breaks for users calling mailq. | |
1302 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1303 | if (!gnutls_allow_auto_pkcs11) |
452a164f JH |
1304 | if ((rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL))) |
1305 | return tls_error_gnu(US"gnutls_pkcs11_init", rc, host, errstr); | |
a5f239e4 PP |
1306 | #endif |
1307 | ||
452a164f JH |
1308 | if ((rc = gnutls_global_init())) |
1309 | return tls_error_gnu(US"gnutls_global_init", rc, host, errstr); | |
17c76198 PP |
1310 | |
1311 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1312 | DEBUG(D_tls) | |
059ec3d9 | 1313 | { |
17c76198 | 1314 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
aded2255 | 1315 | /* arbitrarily chosen level; bump up to 9 for more */ |
17c76198 | 1316 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); |
059ec3d9 | 1317 | } |
17c76198 PP |
1318 | #endif |
1319 | ||
4fb7df6d JH |
1320 | #ifndef DISABLE_OCSP |
1321 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1322 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1323 | #endif |
9196d5bf | 1324 | |
17c76198 | 1325 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1326 | } |
059ec3d9 | 1327 | |
17c76198 PP |
1328 | if (host) |
1329 | { | |
74f1a423 JH |
1330 | /* For client-side sessions we allocate a context. This lets us run |
1331 | several in parallel. */ | |
1332 | int old_pool = store_pool; | |
1333 | store_pool = POOL_PERM; | |
1334 | state = store_get(sizeof(exim_gnutls_state_st)); | |
1335 | store_pool = old_pool; | |
1336 | ||
17c76198 | 1337 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
74f1a423 | 1338 | state->tlsp = tlsp; |
17c76198 PP |
1339 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1340 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1341 | } | |
1342 | else | |
1343 | { | |
1344 | state = &state_server; | |
1345 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
74f1a423 | 1346 | state->tlsp = tlsp; |
17c76198 PP |
1347 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1348 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1349 | } | |
452a164f JH |
1350 | if (rc) |
1351 | return tls_error_gnu(US"gnutls_init", rc, host, errstr); | |
059ec3d9 | 1352 | |
17c76198 | 1353 | state->host = host; |
059ec3d9 | 1354 | |
17c76198 PP |
1355 | state->tls_certificate = certificate; |
1356 | state->tls_privatekey = privatekey; | |
5779e6aa | 1357 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1358 | state->tls_sni = sni; |
1359 | state->tls_verify_certificates = cas; | |
1360 | state->tls_crl = crl; | |
059ec3d9 | 1361 | |
17c76198 PP |
1362 | /* This handles the variables that might get re-expanded after TLS SNI; |
1363 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1364 | |
17c76198 PP |
1365 | DEBUG(D_tls) |
1366 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1367 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1368 | |
1365611d PP |
1369 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1370 | requires a new structure afterwards. */ | |
83da1223 | 1371 | |
cf0c6164 | 1372 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1373 | |
17c76198 PP |
1374 | /* set SNI in client, only */ |
1375 | if (host) | |
1376 | { | |
cf0c6164 | 1377 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1378 | return DEFER; |
0df4ab80 | 1379 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1380 | { |
1381 | DEBUG(D_tls) | |
0df4ab80 JH |
1382 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1383 | sz = Ustrlen(state->tlsp->sni); | |
452a164f JH |
1384 | if ((rc = gnutls_server_name_set(state->session, |
1385 | GNUTLS_NAME_DNS, state->tlsp->sni, sz))) | |
1386 | return tls_error_gnu(US"gnutls_server_name_set", rc, host, errstr); | |
17c76198 PP |
1387 | } |
1388 | } | |
1389 | else if (state->tls_sni) | |
1390 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
ba86e143 | 1391 | "have an SNI set for a server [%s]\n", state->tls_sni); |
83da1223 | 1392 | |
17c76198 | 1393 | /* This is the priority string support, |
42bfef1e | 1394 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1395 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1396 | This was backwards incompatible, but means Exim no longer needs to track | |
1397 | all algorithms and provide string forms for them. */ | |
83da1223 | 1398 | |
fc243e94 | 1399 | p = NULL; |
17c76198 | 1400 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1401 | { |
cf0c6164 | 1402 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1403 | return DEFER; |
1404 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1405 | { |
17c76198 | 1406 | p = state->exp_tls_require_ciphers; |
fc243e94 | 1407 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", p); |
83da1223 PH |
1408 | } |
1409 | } | |
fc243e94 | 1410 | if (!p) |
17c76198 | 1411 | { |
fc243e94 | 1412 | p = exim_default_gnutls_priority; |
83e2f8a2 | 1413 | DEBUG(D_tls) |
fc243e94 | 1414 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", p); |
17c76198 | 1415 | } |
83da1223 | 1416 | |
452a164f JH |
1417 | if ((rc = gnutls_priority_init(&state->priority_cache, CCS p, &errpos))) |
1418 | return tls_error_gnu(string_sprintf( | |
1419 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1420 | p, errpos - CS p, errpos), | |
1421 | rc, host, errstr); | |
17c76198 | 1422 | |
452a164f JH |
1423 | if ((rc = gnutls_priority_set(state->session, state->priority_cache))) |
1424 | return tls_error_gnu(US"gnutls_priority_set", rc, host, errstr); | |
17c76198 PP |
1425 | |
1426 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1427 | ||
1428 | /* Reduce security in favour of increased compatibility, if the admin | |
1429 | decides to make that trade-off. */ | |
1430 | if (gnutls_compat_mode) | |
83da1223 | 1431 | { |
17c76198 PP |
1432 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1433 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1434 | gnutls_session_enable_compatibility_mode(state->session); | |
1435 | #else | |
1436 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1437 | #endif | |
83da1223 PH |
1438 | } |
1439 | ||
17c76198 | 1440 | *caller_state = state; |
17c76198 | 1441 | return OK; |
83da1223 PH |
1442 | } |
1443 | ||
1444 | ||
1445 | ||
059ec3d9 | 1446 | /************************************************* |
17c76198 | 1447 | * Extract peer information * |
059ec3d9 PH |
1448 | *************************************************/ |
1449 | ||
f1be21cf JH |
1450 | static const uschar * |
1451 | cipher_stdname_kcm(gnutls_kx_algorithm_t kx, gnutls_cipher_algorithm_t cipher, | |
1452 | gnutls_mac_algorithm_t mac) | |
1453 | { | |
1454 | uschar cs_id[2]; | |
1455 | gnutls_kx_algorithm_t kx_i; | |
1456 | gnutls_cipher_algorithm_t cipher_i; | |
1457 | gnutls_mac_algorithm_t mac_i; | |
1458 | ||
1459 | for (size_t i = 0; | |
1460 | gnutls_cipher_suite_info(i, cs_id, &kx_i, &cipher_i, &mac_i, NULL); | |
1461 | i++) | |
1462 | if (kx_i == kx && cipher_i == cipher && mac_i == mac) | |
1463 | return cipher_stdname(cs_id[0], cs_id[1]); | |
1464 | return NULL; | |
1465 | } | |
1466 | ||
1467 | ||
1468 | ||
17c76198 | 1469 | /* Called from both server and client code. |
4fe99a6c PP |
1470 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1471 | and we use that to detect double-calls. | |
059ec3d9 | 1472 | |
75fe387d PP |
1473 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1474 | for logging in the server side, but for the client side, we log after teardown | |
1475 | in src/deliver.c. While the session is up, we can twist about states and | |
1476 | repoint tls_* globals, but those variables used for logging or other variable | |
1477 | expansion that happens _after_ delivery need to have a longer life-time. | |
1478 | ||
1479 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1480 | doing this more than once per generation of a state context. We set them in | |
1481 | the state context, and repoint tls_* to them. After the state goes away, the | |
1482 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1483 | ||
1484 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1485 | don't apply. | |
1486 | ||
059ec3d9 | 1487 | Arguments: |
17c76198 | 1488 | state exim_gnutls_state_st * |
cf0c6164 | 1489 | errstr pointer to error string |
059ec3d9 | 1490 | |
17c76198 | 1491 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1492 | */ |
1493 | ||
17c76198 | 1494 | static int |
cf0c6164 | 1495 | peer_status(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 1496 | { |
27f19eb4 | 1497 | const gnutls_datum_t *cert_list; |
75fe387d | 1498 | int old_pool, rc; |
17c76198 | 1499 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1500 | gnutls_protocol_t protocol; |
1501 | gnutls_cipher_algorithm_t cipher; | |
1502 | gnutls_kx_algorithm_t kx; | |
1503 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1504 | gnutls_certificate_type_t ct; |
1505 | gnutls_x509_crt_t crt; | |
d7978c0f | 1506 | uschar *dn_buf; |
17c76198 | 1507 | size_t sz; |
059ec3d9 | 1508 | |
4fe99a6c | 1509 | if (state->have_set_peerdn) |
17c76198 | 1510 | return OK; |
4fe99a6c | 1511 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1512 | |
4fe99a6c | 1513 | state->peerdn = NULL; |
059ec3d9 | 1514 | |
4fe99a6c PP |
1515 | /* tls_cipher */ |
1516 | cipher = gnutls_cipher_get(state->session); | |
1517 | protocol = gnutls_protocol_get_version(state->session); | |
1518 | mac = gnutls_mac_get(state->session); | |
b9c6f63c JH |
1519 | kx = |
1520 | #ifdef GNUTLS_TLS1_3 | |
1521 | protocol >= GNUTLS_TLS1_3 ? 0 : | |
1522 | #endif | |
1523 | gnutls_kx_get(state->session); | |
4fe99a6c | 1524 | |
75fe387d | 1525 | old_pool = store_pool; |
f1be21cf JH |
1526 | { |
1527 | store_pool = POOL_PERM; | |
d9acfc1c JH |
1528 | |
1529 | #ifdef SUPPORT_GNUTLS_SESS_DESC | |
1530 | { | |
1531 | gstring * g = NULL; | |
1532 | uschar * s = US gnutls_session_get_desc(state->session), c; | |
1533 | ||
1534 | /* Nikos M suggests we use this by preference. It returns like: | |
1535 | (TLS1.3)-(ECDHE-SECP256R1)-(RSA-PSS-RSAE-SHA256)-(AES-256-GCM) | |
1536 | ||
1537 | For partial back-compat, put a colon after the TLS version, replace the | |
1538 | )-( grouping with __, replace in-group - with _ and append the :keysize. */ | |
1539 | ||
1540 | /* debug_printf("peer_status: gnutls_session_get_desc %s\n", s); */ | |
1541 | ||
1542 | for (s++; (c = *s) && c != ')'; s++) g = string_catn(g, s, 1); | |
1543 | g = string_catn(g, US":", 1); | |
1544 | if (*s) s++; /* now on _ between groups */ | |
1545 | while ((c = *s)) | |
1546 | { | |
1547 | for (*++s && ++s; (c = *s) && c != ')'; s++) g = string_catn(g, c == '-' ? US"_" : s, 1); | |
1548 | /* now on ) closing group */ | |
1549 | if ((c = *s) && *++s == '-') g = string_catn(g, US"__", 2); | |
1550 | /* now on _ between groups */ | |
1551 | } | |
1552 | g = string_catn(g, US":", 1); | |
1553 | g = string_cat(g, string_sprintf("%d", (int) gnutls_cipher_get_key_size(cipher) * 8)); | |
1554 | state->ciphersuite = string_from_gstring(g); | |
1555 | } | |
1556 | #else | |
f1be21cf JH |
1557 | state->ciphersuite = string_sprintf("%s:%s:%d", |
1558 | gnutls_protocol_get_name(protocol), | |
1559 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1560 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1561 | ||
1562 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1563 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1564 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
1565 | ||
1566 | for (uschar * p = state->ciphersuite; *p; p++) if (isspace(*p)) *p = '-'; | |
d9acfc1c JH |
1567 | #endif |
1568 | ||
1569 | /* debug_printf("peer_status: ciphersuite %s\n", state->ciphersuite); */ | |
1570 | ||
f1be21cf | 1571 | state->tlsp->cipher = state->ciphersuite; |
d9acfc1c | 1572 | state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
f1be21cf JH |
1573 | |
1574 | state->tlsp->cipher_stdname = cipher_stdname_kcm(kx, cipher, mac); | |
1575 | } | |
75fe387d | 1576 | store_pool = old_pool; |
4fe99a6c PP |
1577 | |
1578 | /* tls_peerdn */ | |
17c76198 | 1579 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1580 | |
f1be21cf | 1581 | if (!cert_list || cert_list_size == 0) |
17c76198 | 1582 | { |
17c76198 PP |
1583 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1584 | cert_list, cert_list_size); | |
e51c7be2 | 1585 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1586 | return tls_error(US"certificate verification failed", |
48224640 | 1587 | US"no certificate received from peer", state->host, errstr); |
17c76198 PP |
1588 | return OK; |
1589 | } | |
059ec3d9 | 1590 | |
95f52235 | 1591 | if ((ct = gnutls_certificate_type_get(state->session)) != GNUTLS_CRT_X509) |
059ec3d9 | 1592 | { |
95f52235 | 1593 | const uschar * ctn = US gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1594 | DEBUG(D_tls) |
1595 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1596 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1597 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1598 | ctn, state->host, errstr); |
17c76198 | 1599 | return OK; |
83da1223 | 1600 | } |
059ec3d9 | 1601 | |
e51c7be2 JH |
1602 | #define exim_gnutls_peer_err(Label) \ |
1603 | do { \ | |
1604 | if (rc != GNUTLS_E_SUCCESS) \ | |
1605 | { \ | |
1606 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1607 | (Label), gnutls_strerror(rc)); \ | |
1608 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
452a164f | 1609 | return tls_error_gnu((Label), rc, state->host, errstr); \ |
e51c7be2 JH |
1610 | return OK; \ |
1611 | } \ | |
1612 | } while (0) | |
17c76198 | 1613 | |
9d1c15ef JH |
1614 | rc = import_cert(&cert_list[0], &crt); |
1615 | exim_gnutls_peer_err(US"cert 0"); | |
1616 | ||
1617 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1618 | |
17c76198 PP |
1619 | sz = 0; |
1620 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1621 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1622 | { |
17c76198 PP |
1623 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1624 | return FAIL; /* should not happen */ | |
059ec3d9 | 1625 | } |
17c76198 PP |
1626 | dn_buf = store_get_perm(sz); |
1627 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1628 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1629 | |
17c76198 PP |
1630 | state->peerdn = dn_buf; |
1631 | ||
1632 | return OK; | |
1633 | #undef exim_gnutls_peer_err | |
1634 | } | |
059ec3d9 | 1635 | |
059ec3d9 | 1636 | |
059ec3d9 | 1637 | |
059ec3d9 | 1638 | |
17c76198 PP |
1639 | /************************************************* |
1640 | * Verify peer certificate * | |
1641 | *************************************************/ | |
059ec3d9 | 1642 | |
17c76198 PP |
1643 | /* Called from both server and client code. |
1644 | *Should* be using a callback registered with | |
1645 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1646 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1647 | |
17c76198 | 1648 | Arguments: |
899b8bbc JH |
1649 | state exim_gnutls_state_st * |
1650 | errstr where to put an error message | |
059ec3d9 | 1651 | |
17c76198 PP |
1652 | Returns: |
1653 | FALSE if the session should be rejected | |
1654 | TRUE if the cert is okay or we just don't care | |
1655 | */ | |
059ec3d9 | 1656 | |
17c76198 | 1657 | static BOOL |
28646fa9 | 1658 | verify_certificate(exim_gnutls_state_st * state, uschar ** errstr) |
17c76198 PP |
1659 | { |
1660 | int rc; | |
899b8bbc JH |
1661 | uint verify; |
1662 | ||
1663 | if (state->verify_requirement == VERIFY_NONE) | |
1664 | return TRUE; | |
17c76198 | 1665 | |
8008accd | 1666 | DEBUG(D_tls) debug_printf("TLS: checking peer certificate\n"); |
cf0c6164 | 1667 | *errstr = NULL; |
17c76198 | 1668 | |
95f52235 | 1669 | if ((rc = peer_status(state, errstr)) != OK || !state->peerdn) |
e6060e2c | 1670 | { |
17c76198 | 1671 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1672 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1673 | } |
1674 | else | |
899b8bbc JH |
1675 | |
1676 | { | |
1677 | #ifdef SUPPORT_DANE | |
1678 | if (state->verify_requirement == VERIFY_DANE && state->host) | |
1679 | { | |
1680 | /* Using dane_verify_session_crt() would be easy, as it does it all for us | |
1681 | including talking to a DNS resolver. But we want to do that bit ourselves | |
1682 | as the testsuite intercepts and fakes its own DNS environment. */ | |
1683 | ||
1684 | dane_state_t s; | |
1685 | dane_query_t r; | |
899b8bbc | 1686 | uint lsize; |
94c13285 JH |
1687 | const gnutls_datum_t * certlist = |
1688 | gnutls_certificate_get_peers(state->session, &lsize); | |
1689 | int usage = tls_out.tlsa_usage; | |
1690 | ||
1691 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION | |
1692 | /* Split the TLSA records into two sets, TA and EE selectors. Run the | |
1693 | dane-verification separately so that we know which selector verified; | |
570cb1bd | 1694 | then we know whether to do name-verification (needed for TA but not EE). */ |
94c13285 JH |
1695 | |
1696 | if (usage == ((1<<DANESSL_USAGE_DANE_TA) | (1<<DANESSL_USAGE_DANE_EE))) | |
bd5b3f3c | 1697 | { /* a mixed-usage bundle */ |
94c13285 JH |
1698 | int i, j, nrec; |
1699 | const char ** dd; | |
1700 | int * ddl; | |
1701 | ||
1702 | for(nrec = 0; state->dane_data_len[nrec]; ) nrec++; | |
1703 | nrec++; | |
1704 | ||
1705 | dd = store_get(nrec * sizeof(uschar *)); | |
1706 | ddl = store_get(nrec * sizeof(int)); | |
1707 | nrec--; | |
1708 | ||
1709 | if ((rc = dane_state_init(&s, 0))) | |
1710 | goto tlsa_prob; | |
1711 | ||
1712 | for (usage = DANESSL_USAGE_DANE_EE; | |
1713 | usage >= DANESSL_USAGE_DANE_TA; usage--) | |
1714 | { /* take records with this usage */ | |
1715 | for (j = i = 0; i < nrec; i++) | |
1716 | if (state->dane_data[i][0] == usage) | |
1717 | { | |
1718 | dd[j] = state->dane_data[i]; | |
1719 | ddl[j++] = state->dane_data_len[i]; | |
1720 | } | |
1721 | if (j) | |
1722 | { | |
1723 | dd[j] = NULL; | |
1724 | ddl[j] = 0; | |
1725 | ||
1726 | if ((rc = dane_raw_tlsa(s, &r, (char * const *)dd, ddl, 1, 0))) | |
1727 | goto tlsa_prob; | |
1728 | ||
1729 | if ((rc = dane_verify_crt_raw(s, certlist, lsize, | |
1730 | gnutls_certificate_type_get(state->session), | |
1731 | r, 0, | |
1732 | usage == DANESSL_USAGE_DANE_EE | |
1733 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1734 | &verify))) | |
1735 | { | |
1736 | DEBUG(D_tls) | |
1737 | debug_printf("TLSA record problem: %s\n", dane_strerror(rc)); | |
1738 | } | |
1739 | else if (verify == 0) /* verification passed */ | |
1740 | { | |
1741 | usage = 1 << usage; | |
1742 | break; | |
1743 | } | |
1744 | } | |
1745 | } | |
899b8bbc | 1746 | |
94c13285 JH |
1747 | if (rc) goto tlsa_prob; |
1748 | } | |
1749 | else | |
1750 | # endif | |
899b8bbc | 1751 | { |
94c13285 JH |
1752 | if ( (rc = dane_state_init(&s, 0)) |
1753 | || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len, | |
1754 | 1, 0)) | |
1755 | || (rc = dane_verify_crt_raw(s, certlist, lsize, | |
1756 | gnutls_certificate_type_get(state->session), | |
5ec37a55 | 1757 | r, 0, |
94c13285 JH |
1758 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1759 | usage == (1 << DANESSL_USAGE_DANE_EE) | |
1760 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1761 | # else | |
1762 | 0, | |
1763 | # endif | |
1764 | &verify)) | |
1765 | ) | |
1766 | goto tlsa_prob; | |
899b8bbc | 1767 | } |
94c13285 JH |
1768 | |
1769 | if (verify != 0) /* verification failed */ | |
899b8bbc JH |
1770 | { |
1771 | gnutls_datum_t str; | |
1772 | (void) dane_verification_status_print(verify, &str, 0); | |
1773 | *errstr = US str.data; /* don't bother to free */ | |
1774 | goto badcert; | |
1775 | } | |
28646fa9 | 1776 | |
94c13285 JH |
1777 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1778 | /* If a TA-mode TLSA record was used for verification we must additionally | |
570cb1bd | 1779 | verify the cert name (but not the CA chain). For EE-mode, skip it. */ |
28646fa9 | 1780 | |
94c13285 JH |
1781 | if (usage & (1 << DANESSL_USAGE_DANE_EE)) |
1782 | # endif | |
28646fa9 | 1783 | { |
570cb1bd | 1784 | state->peer_dane_verified = state->peer_cert_verified = TRUE; |
28646fa9 JH |
1785 | goto goodcert; |
1786 | } | |
570cb1bd JH |
1787 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1788 | /* Assume that the name on the A-record is the one that should be matching | |
1789 | the cert. An alternate view is that the domain part of the email address | |
1790 | is also permissible. */ | |
1791 | ||
1792 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, | |
1793 | CS state->host->name)) | |
1794 | { | |
1795 | state->peer_dane_verified = state->peer_cert_verified = TRUE; | |
1796 | goto goodcert; | |
1797 | } | |
1798 | # endif | |
899b8bbc | 1799 | } |
570cb1bd | 1800 | #endif /*SUPPORT_DANE*/ |
899b8bbc | 1801 | |
17c76198 | 1802 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
899b8bbc | 1803 | } |
e6060e2c | 1804 | |
899b8bbc | 1805 | /* Handle the result of verification. INVALID is set if any others are. */ |
059ec3d9 | 1806 | |
28646fa9 | 1807 | if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) |
17c76198 PP |
1808 | { |
1809 | state->peer_cert_verified = FALSE; | |
cf0c6164 | 1810 | if (!*errstr) |
184384c3 JH |
1811 | { |
1812 | #ifdef GNUTLS_CERT_VFY_STATUS_PRINT | |
1813 | DEBUG(D_tls) | |
1814 | { | |
1815 | gnutls_datum_t txt; | |
1816 | ||
1817 | if (gnutls_certificate_verification_status_print(verify, | |
1818 | gnutls_certificate_type_get(state->session), &txt, 0) | |
1819 | == GNUTLS_E_SUCCESS) | |
1820 | { | |
1821 | debug_printf("%s\n", txt.data); | |
1822 | gnutls_free(txt.data); | |
1823 | } | |
1824 | } | |
1825 | #endif | |
cf0c6164 JH |
1826 | *errstr = verify & GNUTLS_CERT_REVOKED |
1827 | ? US"certificate revoked" : US"certificate invalid"; | |
184384c3 | 1828 | } |
059ec3d9 | 1829 | |
17c76198 | 1830 | DEBUG(D_tls) |
e51c7be2 | 1831 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1832 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1833 | |
e51c7be2 | 1834 | if (state->verify_requirement >= VERIFY_REQUIRED) |
899b8bbc | 1835 | goto badcert; |
17c76198 | 1836 | DEBUG(D_tls) |
4789da3a | 1837 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1838 | } |
e51c7be2 | 1839 | |
17c76198 PP |
1840 | else |
1841 | { | |
5fd28bb8 JH |
1842 | /* Client side, check the server's certificate name versus the name on the |
1843 | A-record for the connection we made. What to do for server side - what name | |
1844 | to use for client? We document that there is no such checking for server | |
1845 | side. */ | |
1846 | ||
1847 | if ( state->exp_tls_verify_cert_hostnames | |
1848 | && !gnutls_x509_crt_check_hostname(state->tlsp->peercert, | |
1849 | CS state->exp_tls_verify_cert_hostnames) | |
1850 | ) | |
e51c7be2 | 1851 | { |
5fd28bb8 JH |
1852 | DEBUG(D_tls) |
1853 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
1854 | if (state->verify_requirement >= VERIFY_REQUIRED) | |
1855 | goto badcert; | |
1856 | return TRUE; | |
e51c7be2 | 1857 | } |
5fd28bb8 | 1858 | |
17c76198 | 1859 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1860 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1861 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1862 | } |
059ec3d9 | 1863 | |
28646fa9 JH |
1864 | goodcert: |
1865 | state->tlsp->peerdn = state->peerdn; | |
1866 | return TRUE; | |
899b8bbc | 1867 | |
b83314e3 | 1868 | #ifdef SUPPORT_DANE |
94c13285 | 1869 | tlsa_prob: |
624f33df JH |
1870 | *errstr = string_sprintf("TLSA record problem: %s", |
1871 | rc == DANE_E_REQUESTED_DATA_NOT_AVAILABLE ? "none usable" : dane_strerror(rc)); | |
b83314e3 JH |
1872 | #endif |
1873 | ||
899b8bbc JH |
1874 | badcert: |
1875 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1876 | return FALSE; | |
17c76198 | 1877 | } |
059ec3d9 | 1878 | |
17c76198 PP |
1879 | |
1880 | ||
1881 | ||
1882 | /* ------------------------------------------------------------------------ */ | |
1883 | /* Callbacks */ | |
1884 | ||
1885 | /* Logging function which can be registered with | |
1886 | * gnutls_global_set_log_function() | |
1887 | * gnutls_global_set_log_level() 0..9 | |
1888 | */ | |
af3498d6 | 1889 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1890 | static void |
17c76198 | 1891 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1892 | { |
8c79eebf PP |
1893 | size_t len = strlen(message); |
1894 | if (len < 1) | |
1895 | { | |
1896 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1897 | return; | |
1898 | } | |
1899 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1900 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1901 | } |
af3498d6 | 1902 | #endif |
059ec3d9 | 1903 | |
059ec3d9 | 1904 | |
17c76198 PP |
1905 | /* Called after client hello, should handle SNI work. |
1906 | This will always set tls_sni (state->received_sni) if available, | |
1907 | and may trigger presenting different certificates, | |
1908 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1909 | |
17c76198 PP |
1910 | Should be registered with |
1911 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1912 | |
17c76198 PP |
1913 | "This callback must return 0 on success or a gnutls error code to terminate the |
1914 | handshake.". | |
059ec3d9 | 1915 | |
17c76198 PP |
1916 | For inability to get SNI information, we return 0. |
1917 | We only return non-zero if re-setup failed. | |
817d9f57 | 1918 | Only used for server-side TLS. |
17c76198 | 1919 | */ |
44bbabb5 | 1920 | |
17c76198 PP |
1921 | static int |
1922 | exim_sni_handling_cb(gnutls_session_t session) | |
1923 | { | |
1924 | char sni_name[MAX_HOST_LEN]; | |
1925 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1926 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1927 | unsigned int sni_type; |
1928 | int rc, old_pool; | |
cf0c6164 | 1929 | uschar * dummy_errstr; |
17c76198 PP |
1930 | |
1931 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1932 | if (rc != GNUTLS_E_SUCCESS) |
1933 | { | |
1934 | DEBUG(D_tls) { | |
1935 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1936 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1937 | else | |
1938 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1939 | gnutls_strerror(rc), rc); | |
cf0c6164 | 1940 | } |
b34fc30c PP |
1941 | return 0; |
1942 | } | |
1943 | ||
17c76198 PP |
1944 | if (sni_type != GNUTLS_NAME_DNS) |
1945 | { | |
1946 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1947 | return 0; | |
1948 | } | |
44bbabb5 | 1949 | |
17c76198 PP |
1950 | /* We now have a UTF-8 string in sni_name */ |
1951 | old_pool = store_pool; | |
1952 | store_pool = POOL_PERM; | |
1953 | state->received_sni = string_copyn(US sni_name, data_len); | |
1954 | store_pool = old_pool; | |
1955 | ||
1956 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1957 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1958 | |
1959 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1960 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1961 | ||
1962 | if (!state->trigger_sni_changes) | |
1963 | return 0; | |
1964 | ||
cf0c6164 | 1965 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
1966 | { |
1967 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1968 | been offered. The best we can do now is abort. */ | |
1969 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1970 | } | |
1971 | ||
cf0c6164 | 1972 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
1973 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
1974 | ||
1975 | return 0; | |
059ec3d9 PH |
1976 | } |
1977 | ||
1978 | ||
1979 | ||
f2de3a33 | 1980 | #ifndef DISABLE_OCSP |
44662487 JH |
1981 | |
1982 | static int | |
1983 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1984 | gnutls_datum_t * ocsp_response) | |
1985 | { | |
1986 | int ret; | |
47195144 | 1987 | DEBUG(D_tls) debug_printf("OCSP stapling callback: %s\n", US ptr); |
44662487 | 1988 | |
44662487 JH |
1989 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1990 | { | |
1991 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
5903c6ff | 1992 | CS ptr); |
018058b2 | 1993 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1994 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1995 | } | |
1996 | ||
018058b2 | 1997 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1998 | return 0; |
1999 | } | |
2000 | ||
2001 | #endif | |
2002 | ||
2003 | ||
0cbf2b82 | 2004 | #ifndef DISABLE_EVENT |
a7538db1 JH |
2005 | /* |
2006 | We use this callback to get observability and detail-level control | |
723fe533 JH |
2007 | for an exim TLS connection (either direction), raising a tls:cert event |
2008 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
2009 | can deny verification. |
2010 | ||
2011 | Return 0 for the handshake to continue or non-zero to terminate. | |
2012 | */ | |
2013 | ||
2014 | static int | |
723fe533 | 2015 | verify_cb(gnutls_session_t session) |
a7538db1 | 2016 | { |
27f19eb4 | 2017 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
2018 | unsigned int cert_list_size = 0; |
2019 | gnutls_x509_crt_t crt; | |
2020 | int rc; | |
b30275b8 | 2021 | uschar * yield; |
a7538db1 JH |
2022 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
2023 | ||
bd5b3f3c | 2024 | if ((cert_list = gnutls_certificate_get_peers(session, &cert_list_size))) |
a7538db1 JH |
2025 | while (cert_list_size--) |
2026 | { | |
bd5b3f3c | 2027 | if ((rc = import_cert(&cert_list[cert_list_size], &crt)) != GNUTLS_E_SUCCESS) |
a7538db1 JH |
2028 | { |
2029 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
2030 | cert_list_size, gnutls_strerror(rc)); | |
2031 | break; | |
2032 | } | |
2033 | ||
2034 | state->tlsp->peercert = crt; | |
b30275b8 JH |
2035 | if ((yield = event_raise(state->event_action, |
2036 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
2037 | { |
2038 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
2039 | "SSL verify denied by event-action: depth=%d: %s", |
2040 | cert_list_size, yield); | |
a7538db1 JH |
2041 | return 1; /* reject */ |
2042 | } | |
2043 | state->tlsp->peercert = NULL; | |
2044 | } | |
2045 | ||
2046 | return 0; | |
2047 | } | |
2048 | ||
2049 | #endif | |
44662487 JH |
2050 | |
2051 | ||
f20cfa4a JH |
2052 | static gstring * |
2053 | ddump(gnutls_datum_t * d) | |
2054 | { | |
2055 | gstring * g = string_get((d->size+1) * 2); | |
2056 | uschar * s = d->data; | |
2057 | for (unsigned i = d->size; i > 0; i--, s++) | |
2058 | { | |
2059 | g = string_catn(g, US "0123456789abcdef" + (*s >> 4), 1); | |
2060 | g = string_catn(g, US "0123456789abcdef" + (*s & 0xf), 1); | |
2061 | } | |
2062 | return g; | |
2063 | } | |
17c76198 | 2064 | |
dc6d1769 JH |
2065 | static void |
2066 | post_handshake_debug(exim_gnutls_state_st * state) | |
2067 | { | |
2068 | debug_printf("gnutls_handshake was successful\n"); | |
2069 | #ifdef SUPPORT_GNUTLS_SESS_DESC | |
2070 | debug_printf("%s\n", gnutls_session_get_desc(state->session)); | |
2071 | #endif | |
2072 | #ifdef SUPPORT_GNUTLS_KEYLOG | |
2073 | if (gnutls_protocol_get_version(state->session) < GNUTLS_TLS1_3) | |
2074 | { | |
2075 | gnutls_datum_t c, s; | |
2076 | gstring * gc, * gs; | |
2077 | /* we only want the client random and the master secret */ | |
2078 | gnutls_session_get_random(state->session, &c, &s); | |
2079 | gnutls_session_get_master_secret(state->session, &s); | |
2080 | gc = ddump(&c); | |
2081 | gs = ddump(&s); | |
2082 | debug_printf("CLIENT_RANDOM %.*s %.*s\n", (int)gc->ptr, gc->s, (int)gs->ptr, gs->s); | |
2083 | } | |
2084 | else | |
2085 | debug_printf("To get keying info for TLS1.3 is hard:\n" | |
2086 | " set environment variable SSLKEYLOGFILE to a filename writable by uid exim\n" | |
2087 | " add SSLKEYLOGFILE to keep_environment in the exim config\n" | |
2088 | " run exim as root\n" | |
2089 | " if using sudo, add SSLKEYLOGFILE to env_keep in /etc/sudoers\n"); | |
2090 | #endif | |
2091 | } | |
2092 | ||
17c76198 PP |
2093 | /* ------------------------------------------------------------------------ */ |
2094 | /* Exported functions */ | |
2095 | ||
2096 | ||
2097 | ||
2098 | ||
059ec3d9 PH |
2099 | /************************************************* |
2100 | * Start a TLS session in a server * | |
2101 | *************************************************/ | |
2102 | ||
2103 | /* This is called when Exim is running as a server, after having received | |
2104 | the STARTTLS command. It must respond to that command, and then negotiate | |
2105 | a TLS session. | |
2106 | ||
2107 | Arguments: | |
83da1223 | 2108 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 2109 | errstr pointer to error string |
059ec3d9 PH |
2110 | |
2111 | Returns: OK on success | |
2112 | DEFER for errors before the start of the negotiation | |
4c04137d | 2113 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
2114 | continue running. |
2115 | */ | |
2116 | ||
2117 | int | |
cf0c6164 | 2118 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
2119 | { |
2120 | int rc; | |
cf0c6164 | 2121 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
2122 | |
2123 | /* Check for previous activation */ | |
74f1a423 | 2124 | if (tls_in.active.sock >= 0) |
059ec3d9 | 2125 | { |
48224640 | 2126 | tls_error(US"STARTTLS received after TLS started", US "", NULL, errstr); |
925ac8e4 | 2127 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
2128 | return FAIL; |
2129 | } | |
2130 | ||
2131 | /* Initialize the library. If it fails, it will already have logged the error | |
2132 | and sent an SMTP response. */ | |
2133 | ||
17c76198 | 2134 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 2135 | |
cf0c6164 | 2136 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 2137 | NULL, tls_verify_certificates, tls_crl, |
74f1a423 | 2138 | require_ciphers, &state, &tls_in, errstr)) != OK) return rc; |
059ec3d9 | 2139 | |
059ec3d9 PH |
2140 | /* If this is a host for which certificate verification is mandatory or |
2141 | optional, set up appropriately. */ | |
2142 | ||
059ec3d9 | 2143 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 2144 | { |
e51c7be2 JH |
2145 | DEBUG(D_tls) |
2146 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
2147 | state->verify_requirement = VERIFY_REQUIRED; |
2148 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
2149 | } | |
059ec3d9 | 2150 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 2151 | { |
e51c7be2 JH |
2152 | DEBUG(D_tls) |
2153 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
2154 | state->verify_requirement = VERIFY_OPTIONAL; |
2155 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
2156 | } | |
2157 | else | |
2158 | { | |
e51c7be2 JH |
2159 | DEBUG(D_tls) |
2160 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
2161 | state->verify_requirement = VERIFY_NONE; |
2162 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
2163 | } | |
059ec3d9 | 2164 | |
0cbf2b82 | 2165 | #ifndef DISABLE_EVENT |
723fe533 JH |
2166 | if (event_action) |
2167 | { | |
2168 | state->event_action = event_action; | |
2169 | gnutls_session_set_ptr(state->session, state); | |
2170 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
2171 | } | |
2172 | #endif | |
2173 | ||
17c76198 PP |
2174 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
2175 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 2176 | |
17c76198 PP |
2177 | gnutls_handshake_set_post_client_hello_function(state->session, |
2178 | exim_sni_handling_cb); | |
059ec3d9 PH |
2179 | |
2180 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2181 | on connection, where outputting anything now upsets the clients and tends to | |
2182 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2183 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2184 | mode, the fflush() happens when smtp_getc() is called. */ | |
2185 | ||
817d9f57 | 2186 | if (!state->tlsp->on_connect) |
059ec3d9 | 2187 | { |
925ac8e4 | 2188 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 2189 | fflush(smtp_out); |
059ec3d9 PH |
2190 | } |
2191 | ||
2192 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
8008accd JH |
2193 | that the GnuTLS library doesn't. |
2194 | From 3.1.0 there is gnutls_handshake_set_timeout() - but it requires you | |
2195 | to set (and clear down afterwards) up a pull-timeout callback function that does | |
2196 | a select, so we're no better off unless avoiding signals becomes an issue. */ | |
059ec3d9 | 2197 | |
17c76198 | 2198 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
2199 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
2200 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
2201 | state->fd_in = fileno(smtp_in); |
2202 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
2203 | |
2204 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2205 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
17c76198 | 2206 | do |
17c76198 | 2207 | rc = gnutls_handshake(state->session); |
157a7880 | 2208 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
c2a1bba0 | 2209 | ALARM_CLR(0); |
059ec3d9 | 2210 | |
17c76198 | 2211 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 2212 | { |
059ec3d9 PH |
2213 | /* It seems that, except in the case of a timeout, we have to close the |
2214 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
2215 | until the server times out. */ | |
2216 | ||
60d10ce7 | 2217 | if (sigalrm_seen) |
ad7fc6eb | 2218 | { |
48224640 | 2219 | tls_error(US"gnutls_handshake", US"timed out", NULL, errstr); |
ad7fc6eb JH |
2220 | gnutls_db_remove_session(state->session); |
2221 | } | |
60d10ce7 | 2222 | else |
059ec3d9 | 2223 | { |
452a164f | 2224 | tls_error_gnu(US"gnutls_handshake", rc, NULL, errstr); |
f5d25c2b | 2225 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 2226 | gnutls_deinit(state->session); |
ed62aae3 | 2227 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 2228 | millisleep(500); |
ad7fc6eb | 2229 | shutdown(state->fd_out, SHUT_WR); |
d7978c0f | 2230 | for (int i = 1024; fgetc(smtp_in) != EOF && i > 0; ) i--; /* drain skt */ |
f1e894f3 PH |
2231 | (void)fclose(smtp_out); |
2232 | (void)fclose(smtp_in); | |
60d10ce7 | 2233 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
2234 | } |
2235 | ||
2236 | return FAIL; | |
2237 | } | |
2238 | ||
dc6d1769 | 2239 | DEBUG(D_tls) post_handshake_debug(state); |
059ec3d9 | 2240 | |
17c76198 PP |
2241 | /* Verify after the fact */ |
2242 | ||
899b8bbc | 2243 | if (!verify_certificate(state, errstr)) |
059ec3d9 | 2244 | { |
9d1c15ef | 2245 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 2246 | { |
cf0c6164 | 2247 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 2248 | return FAIL; |
17c76198 | 2249 | } |
9d1c15ef JH |
2250 | DEBUG(D_tls) |
2251 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 2252 | *errstr); |
059ec3d9 PH |
2253 | } |
2254 | ||
17c76198 PP |
2255 | /* Figure out peer DN, and if authenticated, etc. */ |
2256 | ||
cf0c6164 | 2257 | if ((rc = peer_status(state, NULL)) != OK) return rc; |
17c76198 PP |
2258 | |
2259 | /* Sets various Exim expansion variables; always safe within server */ | |
2260 | ||
9d1c15ef | 2261 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
2262 | |
2263 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2264 | and initialize appropriately. */ | |
2265 | ||
17c76198 | 2266 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
2267 | |
2268 | receive_getc = tls_getc; | |
0d81dabc | 2269 | receive_getbuf = tls_getbuf; |
584e96c6 | 2270 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2271 | receive_ungetc = tls_ungetc; |
2272 | receive_feof = tls_feof; | |
2273 | receive_ferror = tls_ferror; | |
58eb016e | 2274 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2275 | |
059ec3d9 PH |
2276 | return OK; |
2277 | } | |
2278 | ||
2279 | ||
2280 | ||
2281 | ||
aa2a70ba JH |
2282 | static void |
2283 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
2284 | smtp_transport_options_block * ob) | |
2285 | { | |
3fb3231c | 2286 | if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 2287 | { |
4af0d74a | 2288 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 2289 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2290 | string_domain_utf8_to_alabel(host->name, NULL); |
2291 | #else | |
2292 | host->name; | |
2293 | #endif | |
aa2a70ba JH |
2294 | DEBUG(D_tls) |
2295 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
2296 | state->exp_tls_verify_cert_hostnames); | |
2297 | } | |
2298 | } | |
aa2a70ba JH |
2299 | |
2300 | ||
899b8bbc JH |
2301 | |
2302 | ||
2303 | #ifdef SUPPORT_DANE | |
2304 | /* Given our list of RRs from the TLSA lookup, build a lookup block in | |
2305 | GnuTLS-DANE's preferred format. Hang it on the state str for later | |
2306 | use in DANE verification. | |
2307 | ||
2308 | We point at the dnsa data not copy it, so it must remain valid until | |
2309 | after verification is done.*/ | |
2310 | ||
3674140c | 2311 | static BOOL |
899b8bbc JH |
2312 | dane_tlsa_load(exim_gnutls_state_st * state, dns_answer * dnsa) |
2313 | { | |
899b8bbc JH |
2314 | dns_scan dnss; |
2315 | int i; | |
2316 | const char ** dane_data; | |
2317 | int * dane_data_len; | |
2318 | ||
d7978c0f JH |
2319 | i = 1; |
2320 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; | |
899b8bbc JH |
2321 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
2322 | ) if (rr->type == T_TLSA) i++; | |
2323 | ||
2324 | dane_data = store_get(i * sizeof(uschar *)); | |
2325 | dane_data_len = store_get(i * sizeof(int)); | |
2326 | ||
d7978c0f JH |
2327 | i = 0; |
2328 | for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; | |
899b8bbc | 2329 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) |
1b76ad22 | 2330 | ) if (rr->type == T_TLSA && rr->size > 3) |
899b8bbc JH |
2331 | { |
2332 | const uschar * p = rr->data; | |
3674140c JH |
2333 | uint8_t usage = p[0], sel = p[1], type = p[2]; |
2334 | ||
2335 | DEBUG(D_tls) | |
2336 | debug_printf("TLSA: %d %d %d size %d\n", usage, sel, type, rr->size); | |
2337 | ||
94c13285 JH |
2338 | if ( (usage != DANESSL_USAGE_DANE_TA && usage != DANESSL_USAGE_DANE_EE) |
2339 | || (sel != 0 && sel != 1) | |
2340 | ) | |
2341 | continue; | |
3674140c JH |
2342 | switch(type) |
2343 | { | |
2344 | case 0: /* Full: cannot check at present */ | |
2345 | break; | |
2346 | case 1: if (rr->size != 3 + 256/8) continue; /* sha2-256 */ | |
2347 | break; | |
2348 | case 2: if (rr->size != 3 + 512/8) continue; /* sha2-512 */ | |
2349 | break; | |
2350 | default: continue; | |
2351 | } | |
899b8bbc JH |
2352 | |
2353 | tls_out.tlsa_usage |= 1<<usage; | |
48224640 | 2354 | dane_data[i] = CS p; |
899b8bbc JH |
2355 | dane_data_len[i++] = rr->size; |
2356 | } | |
3674140c JH |
2357 | |
2358 | if (!i) return FALSE; | |
2359 | ||
899b8bbc JH |
2360 | dane_data[i] = NULL; |
2361 | dane_data_len[i] = 0; | |
2362 | ||
2363 | state->dane_data = (char * const *)dane_data; | |
2364 | state->dane_data_len = dane_data_len; | |
3674140c | 2365 | return TRUE; |
899b8bbc JH |
2366 | } |
2367 | #endif | |
2368 | ||
2369 | ||
2370 | ||
059ec3d9 PH |
2371 | /************************************************* |
2372 | * Start a TLS session in a client * | |
2373 | *************************************************/ | |
2374 | ||
2375 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2376 | ||
2377 | Arguments: | |
c05bdbd6 JH |
2378 | cctx connection context |
2379 | conn_args connection details | |
2380 | cookie datum for randomness (not used) | |
2381 | tlsp record details of channel configuration here; must be non-NULL | |
2382 | errstr error string pointer | |
2383 | ||
2384 | Returns: TRUE for success with TLS session context set in smtp context, | |
2385 | FALSE on error | |
059ec3d9 PH |
2386 | */ |
2387 | ||
c05bdbd6 JH |
2388 | BOOL |
2389 | tls_client_start(client_conn_ctx * cctx, smtp_connect_args * conn_args, | |
2390 | void * cookie ARG_UNUSED, | |
2391 | tls_support * tlsp, uschar ** errstr) | |
059ec3d9 | 2392 | { |
c05bdbd6 JH |
2393 | host_item * host = conn_args->host; /* for msgs and option-tests */ |
2394 | transport_instance * tb = conn_args->tblock; /* always smtp or NULL */ | |
2395 | smtp_transport_options_block * ob = tb | |
afdb5e9c JH |
2396 | ? (smtp_transport_options_block *)tb->options_block |
2397 | : &smtp_transport_option_defaults; | |
059ec3d9 | 2398 | int rc; |
899b8bbc | 2399 | exim_gnutls_state_st * state = NULL; |
c05bdbd6 | 2400 | uschar * cipher_list = NULL; |
74f1a423 | 2401 | |
f2de3a33 | 2402 | #ifndef DISABLE_OCSP |
5130845b | 2403 | BOOL require_ocsp = |
3fb3231c | 2404 | verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; |
44662487 | 2405 | BOOL request_ocsp = require_ocsp ? TRUE |
3fb3231c | 2406 | : verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 2407 | #endif |
059ec3d9 | 2408 | |
c05bdbd6 | 2409 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", cctx->sock); |
059ec3d9 | 2410 | |
5ec37a55 | 2411 | #ifdef SUPPORT_DANE |
c05bdbd6 JH |
2412 | /* If dane is flagged, have either request or require dane for this host, and |
2413 | a TLSA record found. Therefore, dane verify required. Which implies cert must | |
2414 | be requested and supplied, dane verify must pass, and cert verify irrelevant | |
2415 | (incl. hostnames), and (caller handled) require_tls */ | |
2416 | ||
2417 | if (conn_args->dane && ob->dane_require_tls_ciphers) | |
5ec37a55 PP |
2418 | { |
2419 | /* not using expand_check_tlsvar because not yet in state */ | |
2420 | if (!expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2421 | &cipher_list, errstr)) | |
c05bdbd6 | 2422 | return FALSE; |
cf260049 JH |
2423 | cipher_list = cipher_list && *cipher_list |
2424 | ? ob->dane_require_tls_ciphers : ob->tls_require_ciphers; | |
5ec37a55 PP |
2425 | } |
2426 | #endif | |
2427 | ||
2428 | if (!cipher_list) | |
2429 | cipher_list = ob->tls_require_ciphers; | |
2430 | ||
74f1a423 | 2431 | if (tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
65867078 | 2432 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, |
74f1a423 | 2433 | cipher_list, &state, tlsp, errstr) != OK) |
c05bdbd6 | 2434 | return FALSE; |
059ec3d9 | 2435 | |
54c90be1 | 2436 | { |
65867078 JH |
2437 | int dh_min_bits = ob->tls_dh_min_bits; |
2438 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2439 | { | |
2440 | DEBUG(D_tls) | |
2441 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2442 | " clamping %d up to %d\n", | |
2443 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2444 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2445 | } | |
54c90be1 | 2446 | |
65867078 JH |
2447 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2448 | " acceptable bits to %d\n", | |
2449 | dh_min_bits); | |
2450 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2451 | } | |
83da1223 | 2452 | |
94431adb | 2453 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2454 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2455 | the specified host patterns if one of them is defined */ | |
2456 | ||
899b8bbc | 2457 | #ifdef SUPPORT_DANE |
c05bdbd6 | 2458 | if (conn_args->dane && dane_tlsa_load(state, &conn_args->tlsa_dnsa)) |
899b8bbc JH |
2459 | { |
2460 | DEBUG(D_tls) | |
2461 | debug_printf("TLS: server certificate DANE required.\n"); | |
2462 | state->verify_requirement = VERIFY_DANE; | |
2463 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
899b8bbc JH |
2464 | } |
2465 | else | |
2466 | #endif | |
2467 | if ( ( state->exp_tls_verify_certificates | |
2468 | && !ob->tls_verify_hosts | |
2469 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2470 | ) | |
3fb3231c | 2471 | || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK |
899b8bbc | 2472 | ) |
17c76198 | 2473 | { |
aa2a70ba | 2474 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2475 | DEBUG(D_tls) |
2476 | debug_printf("TLS: server certificate verification required.\n"); | |
2477 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2478 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2479 | } | |
3fb3231c | 2480 | else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2481 | { |
aa2a70ba | 2482 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2483 | DEBUG(D_tls) |
2484 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2485 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2486 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2487 | } | |
2488 | else | |
2489 | { | |
e51c7be2 JH |
2490 | DEBUG(D_tls) |
2491 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2492 | state->verify_requirement = VERIFY_NONE; |
2493 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2494 | } |
059ec3d9 | 2495 | |
f2de3a33 JH |
2496 | #ifndef DISABLE_OCSP |
2497 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2498 | if (request_ocsp) |
9d1c15ef JH |
2499 | { |
2500 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2501 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2502 | NULL, 0, NULL)) != OK) | |
74f1a423 | 2503 | { |
452a164f | 2504 | tls_error_gnu(US"cert-status-req", rc, state->host, errstr); |
c05bdbd6 | 2505 | return FALSE; |
74f1a423 JH |
2506 | } |
2507 | tlsp->ocsp = OCSP_NOT_RESP; | |
9d1c15ef | 2508 | } |
2b4a568d JH |
2509 | #endif |
2510 | ||
0cbf2b82 | 2511 | #ifndef DISABLE_EVENT |
afdb5e9c | 2512 | if (tb && tb->event_action) |
a7538db1 | 2513 | { |
774ef2d7 | 2514 | state->event_action = tb->event_action; |
a7538db1 | 2515 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2516 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2517 | } |
2518 | #endif | |
2519 | ||
c05bdbd6 JH |
2520 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) cctx->sock); |
2521 | state->fd_in = cctx->sock; | |
2522 | state->fd_out = cctx->sock; | |
059ec3d9 | 2523 | |
9d1c15ef | 2524 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2525 | /* There doesn't seem to be a built-in timeout on connection. */ |
2526 | ||
2527 | sigalrm_seen = FALSE; | |
c2a1bba0 | 2528 | ALARM(ob->command_timeout); |
17c76198 | 2529 | do |
17c76198 | 2530 | rc = gnutls_handshake(state->session); |
f1fed05b | 2531 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
c2a1bba0 | 2532 | ALARM_CLR(0); |
059ec3d9 | 2533 | |
4fe99a6c | 2534 | if (rc != GNUTLS_E_SUCCESS) |
74f1a423 | 2535 | { |
60d10ce7 JH |
2536 | if (sigalrm_seen) |
2537 | { | |
2538 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
48224640 | 2539 | tls_error(US"gnutls_handshake", US"timed out", state->host, errstr); |
60d10ce7 JH |
2540 | } |
2541 | else | |
452a164f | 2542 | tls_error_gnu(US"gnutls_handshake", rc, state->host, errstr); |
c05bdbd6 | 2543 | return FALSE; |
74f1a423 | 2544 | } |
4fe99a6c | 2545 | |
dc6d1769 | 2546 | DEBUG(D_tls) post_handshake_debug(state); |
059ec3d9 | 2547 | |
17c76198 | 2548 | /* Verify late */ |
059ec3d9 | 2549 | |
899b8bbc | 2550 | if (!verify_certificate(state, errstr)) |
74f1a423 JH |
2551 | { |
2552 | tls_error(US"certificate verification failed", *errstr, state->host, errstr); | |
c05bdbd6 | 2553 | return FALSE; |
74f1a423 | 2554 | } |
059ec3d9 | 2555 | |
f2de3a33 | 2556 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2557 | if (require_ocsp) |
2558 | { | |
2559 | DEBUG(D_tls) | |
2560 | { | |
2561 | gnutls_datum_t stapling; | |
2562 | gnutls_ocsp_resp_t resp; | |
2563 | gnutls_datum_t printed; | |
2564 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2565 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2566 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2567 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2568 | ) | |
2569 | { | |
65867078 | 2570 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2571 | gnutls_free(printed.data); |
2572 | } | |
2573 | else | |
452a164f | 2574 | (void) tls_error_gnu(US"ocsp decode", rc, state->host, errstr); |
2b4a568d JH |
2575 | } |
2576 | ||
2b4a568d | 2577 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 | 2578 | { |
74f1a423 JH |
2579 | tlsp->ocsp = OCSP_FAILED; |
2580 | tls_error(US"certificate status check failed", NULL, state->host, errstr); | |
c05bdbd6 | 2581 | return FALSE; |
018058b2 | 2582 | } |
2b4a568d | 2583 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
74f1a423 | 2584 | tlsp->ocsp = OCSP_VFIED; |
2b4a568d JH |
2585 | } |
2586 | #endif | |
2587 | ||
17c76198 | 2588 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2589 | |
74f1a423 | 2590 | if (peer_status(state, errstr) != OK) |
c05bdbd6 | 2591 | return FALSE; |
059ec3d9 | 2592 | |
4fe99a6c | 2593 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2594 | |
9d1c15ef | 2595 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2596 | |
c05bdbd6 JH |
2597 | cctx->tls_ctx = state; |
2598 | return TRUE; | |
059ec3d9 PH |
2599 | } |
2600 | ||
2601 | ||
2602 | ||
17c76198 | 2603 | |
059ec3d9 | 2604 | /************************************************* |
17c76198 | 2605 | * Close down a TLS session * |
059ec3d9 PH |
2606 | *************************************************/ |
2607 | ||
17c76198 PP |
2608 | /* This is also called from within a delivery subprocess forked from the |
2609 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2610 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2611 | |
dec766a1 | 2612 | Arguments: |
74f1a423 | 2613 | ct_ctx client context pointer, or NULL for the one global server context |
dec766a1 | 2614 | shutdown 1 if TLS close-alert is to be sent, |
afdb5e9c | 2615 | 2 if also response to be waited for |
dec766a1 | 2616 | |
17c76198 | 2617 | Returns: nothing |
059ec3d9 PH |
2618 | */ |
2619 | ||
17c76198 | 2620 | void |
74f1a423 | 2621 | tls_close(void * ct_ctx, int shutdown) |
059ec3d9 | 2622 | { |
74f1a423 | 2623 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
059ec3d9 | 2624 | |
74f1a423 | 2625 | if (!state->tlsp || state->tlsp->active.sock < 0) return; /* TLS was not active */ |
17c76198 PP |
2626 | |
2627 | if (shutdown) | |
2628 | { | |
dec766a1 WB |
2629 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", |
2630 | shutdown > 1 ? " (with response-wait)" : ""); | |
2631 | ||
c2a1bba0 | 2632 | ALARM(2); |
dec766a1 | 2633 | gnutls_bye(state->session, shutdown > 1 ? GNUTLS_SHUT_RDWR : GNUTLS_SHUT_WR); |
c2a1bba0 | 2634 | ALARM_CLR(0); |
17c76198 PP |
2635 | } |
2636 | ||
2637 | gnutls_deinit(state->session); | |
ed62aae3 HSHR |
2638 | gnutls_certificate_free_credentials(state->x509_cred); |
2639 | ||
17c76198 | 2640 | |
74f1a423 JH |
2641 | state->tlsp->active.sock = -1; |
2642 | state->tlsp->active.tls_ctx = NULL; | |
b808677c | 2643 | if (state->xfer_buffer) store_free(state->xfer_buffer); |
17c76198 | 2644 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
059ec3d9 PH |
2645 | } |
2646 | ||
2647 | ||
2648 | ||
17c76198 | 2649 | |
0d81dabc JH |
2650 | static BOOL |
2651 | tls_refill(unsigned lim) | |
2652 | { | |
2653 | exim_gnutls_state_st * state = &state_server; | |
2654 | ssize_t inbytes; | |
2655 | ||
2656 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2657 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2658 | ||
f1fed05b | 2659 | sigalrm_seen = FALSE; |
c2a1bba0 | 2660 | if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); |
4896a319 AM |
2661 | |
2662 | do | |
2663 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2664 | MIN(ssl_xfer_buffer_size, lim)); | |
2665 | while (inbytes == GNUTLS_E_AGAIN); | |
2666 | ||
c2a1bba0 | 2667 | if (smtp_receive_timeout > 0) ALARM_CLR(0); |
9723f966 JH |
2668 | |
2669 | if (had_command_timeout) /* set by signal handler */ | |
2670 | smtp_command_timeout_exit(); /* does not return */ | |
2671 | if (had_command_sigterm) | |
2672 | smtp_command_sigterm_exit(); | |
2673 | if (had_data_timeout) | |
2674 | smtp_data_timeout_exit(); | |
2675 | if (had_data_sigint) | |
2676 | smtp_data_sigint_exit(); | |
2677 | ||
2678 | /* Timeouts do not get this far. A zero-byte return appears to mean that the | |
2679 | TLS session has been closed down, not that the socket itself has been closed | |
2680 | down. Revert to non-TLS handling. */ | |
0d81dabc JH |
2681 | |
2682 | if (sigalrm_seen) | |
2683 | { | |
2684 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
8b77d27a | 2685 | state->xfer_error = TRUE; |
0d81dabc JH |
2686 | return FALSE; |
2687 | } | |
2688 | ||
2689 | else if (inbytes == 0) | |
2690 | { | |
2691 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2692 | ||
2693 | receive_getc = smtp_getc; | |
2694 | receive_getbuf = smtp_getbuf; | |
2695 | receive_get_cache = smtp_get_cache; | |
2696 | receive_ungetc = smtp_ungetc; | |
2697 | receive_feof = smtp_feof; | |
2698 | receive_ferror = smtp_ferror; | |
2699 | receive_smtp_buffered = smtp_buffered; | |
2700 | ||
2701 | gnutls_deinit(state->session); | |
2702 | gnutls_certificate_free_credentials(state->x509_cred); | |
2703 | ||
2704 | state->session = NULL; | |
74f1a423 JH |
2705 | state->tlsp->active.sock = -1; |
2706 | state->tlsp->active.tls_ctx = NULL; | |
0d81dabc JH |
2707 | state->tlsp->bits = 0; |
2708 | state->tlsp->certificate_verified = FALSE; | |
2709 | tls_channelbinding_b64 = NULL; | |
2710 | state->tlsp->cipher = NULL; | |
2711 | state->tlsp->peercert = NULL; | |
2712 | state->tlsp->peerdn = NULL; | |
2713 | ||
2714 | return FALSE; | |
2715 | } | |
2716 | ||
2717 | /* Handle genuine errors */ | |
2718 | ||
2719 | else if (inbytes < 0) | |
2720 | { | |
95f52235 | 2721 | DEBUG(D_tls) debug_printf("%s: err from gnutls_record_recv\n", __FUNCTION__); |
0d81dabc | 2722 | record_io_error(state, (int) inbytes, US"recv", NULL); |
8b77d27a | 2723 | state->xfer_error = TRUE; |
0d81dabc JH |
2724 | return FALSE; |
2725 | } | |
2726 | #ifndef DISABLE_DKIM | |
2727 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
2728 | #endif | |
2729 | state->xfer_buffer_hwm = (int) inbytes; | |
2730 | state->xfer_buffer_lwm = 0; | |
2731 | return TRUE; | |
2732 | } | |
2733 | ||
059ec3d9 PH |
2734 | /************************************************* |
2735 | * TLS version of getc * | |
2736 | *************************************************/ | |
2737 | ||
2738 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2739 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2740 | Only used by the server-side TLS. |
059ec3d9 | 2741 | |
17c76198 PP |
2742 | This feeds DKIM and should be used for all message-body reads. |
2743 | ||
aded2255 | 2744 | Arguments: lim Maximum amount to read/buffer |
059ec3d9 PH |
2745 | Returns: the next character or EOF |
2746 | */ | |
2747 | ||
2748 | int | |
bd8fbe36 | 2749 | tls_getc(unsigned lim) |
059ec3d9 | 2750 | { |
0d81dabc | 2751 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 2752 | |
0d81dabc JH |
2753 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2754 | if (!tls_refill(lim)) | |
2755 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 2756 | |
0d81dabc | 2757 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2758 | |
0d81dabc JH |
2759 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
2760 | } | |
059ec3d9 | 2761 | |
0d81dabc JH |
2762 | uschar * |
2763 | tls_getbuf(unsigned * len) | |
2764 | { | |
2765 | exim_gnutls_state_st * state = &state_server; | |
2766 | unsigned size; | |
2767 | uschar * buf; | |
059ec3d9 | 2768 | |
0d81dabc JH |
2769 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2770 | if (!tls_refill(*len)) | |
059ec3d9 | 2771 | { |
0d81dabc JH |
2772 | if (!state->xfer_error) return smtp_getbuf(len); |
2773 | *len = 0; | |
2774 | return NULL; | |
059ec3d9 | 2775 | } |
059ec3d9 | 2776 | |
0d81dabc JH |
2777 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
2778 | size = *len; | |
2779 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
2780 | state->xfer_buffer_lwm += size; | |
2781 | *len = size; | |
2782 | return buf; | |
059ec3d9 PH |
2783 | } |
2784 | ||
0d81dabc | 2785 | |
584e96c6 JH |
2786 | void |
2787 | tls_get_cache() | |
2788 | { | |
9960d1e5 | 2789 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2790 | exim_gnutls_state_st * state = &state_server; |
2791 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2792 | if (n > 0) | |
2793 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2794 | #endif |
9960d1e5 | 2795 | } |
584e96c6 | 2796 | |
059ec3d9 | 2797 | |
925ac8e4 JH |
2798 | BOOL |
2799 | tls_could_read(void) | |
2800 | { | |
2801 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
2802 | || gnutls_record_check_pending(state_server.session) > 0; | |
2803 | } | |
2804 | ||
2805 | ||
059ec3d9 | 2806 | |
17c76198 | 2807 | |
059ec3d9 PH |
2808 | /************************************************* |
2809 | * Read bytes from TLS channel * | |
2810 | *************************************************/ | |
2811 | ||
17c76198 PP |
2812 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2813 | then the caller must feed DKIM. | |
817d9f57 | 2814 | |
059ec3d9 | 2815 | Arguments: |
74f1a423 | 2816 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2817 | buff buffer of data |
2818 | len size of buffer | |
2819 | ||
2820 | Returns: the number of bytes read | |
afdb5e9c | 2821 | -1 after a failed read, including EOF |
059ec3d9 PH |
2822 | */ |
2823 | ||
2824 | int | |
74f1a423 | 2825 | tls_read(void * ct_ctx, uschar *buff, size_t len) |
059ec3d9 | 2826 | { |
74f1a423 | 2827 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
17c76198 | 2828 | ssize_t inbytes; |
059ec3d9 | 2829 | |
17c76198 PP |
2830 | if (len > INT_MAX) |
2831 | len = INT_MAX; | |
059ec3d9 | 2832 | |
17c76198 PP |
2833 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2834 | DEBUG(D_tls) | |
2835 | debug_printf("*** PROBABLY A BUG *** " \ | |
2836 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2837 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2838 | ||
2839 | DEBUG(D_tls) | |
2840 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2841 | state->session, buff, len); | |
2842 | ||
4896a319 AM |
2843 | do |
2844 | inbytes = gnutls_record_recv(state->session, buff, len); | |
2845 | while (inbytes == GNUTLS_E_AGAIN); | |
2846 | ||
059ec3d9 PH |
2847 | if (inbytes > 0) return inbytes; |
2848 | if (inbytes == 0) | |
2849 | { | |
2850 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2851 | } | |
5fd28bb8 | 2852 | else |
4896a319 | 2853 | { |
95f52235 | 2854 | DEBUG(D_tls) debug_printf("%s: err from gnutls_record_recv\n", __FUNCTION__); |
4896a319 AM |
2855 | record_io_error(state, (int)inbytes, US"recv", NULL); |
2856 | } | |
059ec3d9 PH |
2857 | |
2858 | return -1; | |
2859 | } | |
2860 | ||
2861 | ||
2862 | ||
17c76198 | 2863 | |
059ec3d9 PH |
2864 | /************************************************* |
2865 | * Write bytes down TLS channel * | |
2866 | *************************************************/ | |
2867 | ||
2868 | /* | |
2869 | Arguments: | |
74f1a423 | 2870 | ct_ctx client context pointer, or NULL for the one global server context |
059ec3d9 PH |
2871 | buff buffer of data |
2872 | len number of bytes | |
925ac8e4 | 2873 | more more data expected soon |
059ec3d9 PH |
2874 | |
2875 | Returns: the number of bytes after a successful write, | |
2876 | -1 after a failed write | |
2877 | */ | |
2878 | ||
2879 | int | |
74f1a423 | 2880 | tls_write(void * ct_ctx, const uschar * buff, size_t len, BOOL more) |
059ec3d9 | 2881 | { |
17c76198 PP |
2882 | ssize_t outbytes; |
2883 | size_t left = len; | |
74f1a423 | 2884 | exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; |
925ac8e4 JH |
2885 | #ifdef SUPPORT_CORK |
2886 | static BOOL corked = FALSE; | |
2887 | ||
2888 | if (more && !corked) gnutls_record_cork(state->session); | |
2889 | #endif | |
2890 | ||
2891 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
2892 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 2893 | |
059ec3d9 PH |
2894 | while (left > 0) |
2895 | { | |
17c76198 PP |
2896 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2897 | buff, left); | |
4896a319 AM |
2898 | |
2899 | do | |
2900 | outbytes = gnutls_record_send(state->session, buff, left); | |
2901 | while (outbytes == GNUTLS_E_AGAIN); | |
059ec3d9 | 2902 | |
17c76198 | 2903 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2904 | if (outbytes < 0) |
2905 | { | |
1b76ad22 | 2906 | DEBUG(D_tls) debug_printf("%s: gnutls_record_send err\n", __FUNCTION__); |
17c76198 | 2907 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2908 | return -1; |
2909 | } | |
2910 | if (outbytes == 0) | |
2911 | { | |
17c76198 | 2912 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2913 | return -1; |
2914 | } | |
2915 | ||
2916 | left -= outbytes; | |
2917 | buff += outbytes; | |
2918 | } | |
2919 | ||
17c76198 PP |
2920 | if (len > INT_MAX) |
2921 | { | |
2922 | DEBUG(D_tls) | |
2923 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2924 | len); | |
2925 | len = INT_MAX; | |
2926 | } | |
2927 | ||
925ac8e4 JH |
2928 | #ifdef SUPPORT_CORK |
2929 | if (more != corked) | |
2930 | { | |
2931 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
2932 | corked = more; | |
2933 | } | |
2934 | #endif | |
2935 | ||
17c76198 | 2936 | return (int) len; |
059ec3d9 PH |
2937 | } |
2938 | ||
2939 | ||
2940 | ||
17c76198 | 2941 | |
059ec3d9 | 2942 | /************************************************* |
17c76198 | 2943 | * Random number generation * |
059ec3d9 PH |
2944 | *************************************************/ |
2945 | ||
17c76198 PP |
2946 | /* Pseudo-random number generation. The result is not expected to be |
2947 | cryptographically strong but not so weak that someone will shoot themselves | |
2948 | in the foot using it as a nonce in input in some email header scheme or | |
2949 | whatever weirdness they'll twist this into. The result should handle fork() | |
2950 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2951 | |
17c76198 PP |
2952 | Arguments: |
2953 | max range maximum | |
2954 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2955 | */ |
2956 | ||
af3498d6 | 2957 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2958 | int |
2959 | vaguely_random_number(int max) | |
059ec3d9 | 2960 | { |
17c76198 PP |
2961 | unsigned int r; |
2962 | int i, needed_len; | |
17c76198 PP |
2963 | uschar smallbuf[sizeof(r)]; |
2964 | ||
2965 | if (max <= 1) | |
2966 | return 0; | |
2967 | ||
2968 | needed_len = sizeof(r); | |
2969 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
d7978c0f JH |
2970 | asked for a number less than 10. */ |
2971 | ||
17c76198 PP |
2972 | for (r = max, i = 0; r; ++i) |
2973 | r >>= 1; | |
2974 | i = (i + 7) / 8; | |
2975 | if (i < needed_len) | |
2976 | needed_len = i; | |
2977 | ||
2978 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2979 | if (i < 0) | |
059ec3d9 | 2980 | { |
17c76198 PP |
2981 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2982 | return vaguely_random_number_fallback(max); | |
2983 | } | |
2984 | r = 0; | |
d7978c0f JH |
2985 | for (uschar * p = smallbuf; needed_len; --needed_len, ++p) |
2986 | r = r * 256 + *p; | |
059ec3d9 | 2987 | |
17c76198 PP |
2988 | /* We don't particularly care about weighted results; if someone wants |
2989 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2990 | return r % max; | |
059ec3d9 | 2991 | } |
af3498d6 PP |
2992 | #else /* HAVE_GNUTLS_RND */ |
2993 | int | |
2994 | vaguely_random_number(int max) | |
2995 | { | |
2996 | return vaguely_random_number_fallback(max); | |
2997 | } | |
2998 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2999 | |
36f12725 NM |
3000 | |
3001 | ||
3002 | ||
3375e053 PP |
3003 | /************************************************* |
3004 | * Let tls_require_ciphers be checked at startup * | |
3005 | *************************************************/ | |
3006 | ||
3007 | /* The tls_require_ciphers option, if set, must be something which the | |
3008 | library can parse. | |
3009 | ||
3010 | Returns: NULL on success, or error message | |
3011 | */ | |
3012 | ||
3013 | uschar * | |
3014 | tls_validate_require_cipher(void) | |
3015 | { | |
3016 | int rc; | |
3017 | uschar *expciphers = NULL; | |
3018 | gnutls_priority_t priority_cache; | |
3019 | const char *errpos; | |
cf0c6164 | 3020 | uschar * dummy_errstr; |
3375e053 PP |
3021 | |
3022 | #define validate_check_rc(Label) do { \ | |
3023 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
3024 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
3025 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
3026 | ||
3027 | if (exim_gnutls_base_init_done) | |
3028 | log_write(0, LOG_MAIN|LOG_PANIC, | |
3029 | "already initialised GnuTLS, Exim developer bug"); | |
3030 | ||
a5f239e4 | 3031 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 3032 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
3033 | { |
3034 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
3035 | validate_check_rc(US"gnutls_pkcs11_init"); | |
3036 | } | |
3037 | #endif | |
3375e053 PP |
3038 | rc = gnutls_global_init(); |
3039 | validate_check_rc(US"gnutls_global_init()"); | |
3040 | exim_gnutls_base_init_done = TRUE; | |
3041 | ||
3042 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
3043 | return_deinit(NULL); | |
3044 | ||
cf0c6164 JH |
3045 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
3046 | &dummy_errstr)) | |
3375e053 PP |
3047 | return_deinit(US"failed to expand tls_require_ciphers"); |
3048 | ||
3049 | if (!(expciphers && *expciphers)) | |
3050 | return_deinit(NULL); | |
3051 | ||
3052 | DEBUG(D_tls) | |
3053 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
3054 | ||
3055 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
3056 | validate_check_rc(string_sprintf( | |
3057 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
3058 | expciphers, errpos - CS expciphers, errpos)); | |
3059 | ||
3060 | #undef return_deinit | |
3061 | #undef validate_check_rc | |
3062 | gnutls_global_deinit(); | |
3063 | ||
3064 | return NULL; | |
3065 | } | |
3066 | ||
3067 | ||
3068 | ||
3069 | ||
36f12725 NM |
3070 | /************************************************* |
3071 | * Report the library versions. * | |
3072 | *************************************************/ | |
3073 | ||
3074 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
3075 | ||
3076 | Arguments: a FILE* to print the results to | |
3077 | Returns: nothing | |
3078 | */ | |
3079 | ||
3080 | void | |
3081 | tls_version_report(FILE *f) | |
3082 | { | |
754a0503 PP |
3083 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
3084 | " Runtime: %s\n", | |
3085 | LIBGNUTLS_VERSION, | |
3086 | gnutls_check_version(NULL)); | |
36f12725 NM |
3087 | } |
3088 | ||
2b4a568d JH |
3089 | /* vi: aw ai sw=2 |
3090 | */ | |
059ec3d9 | 3091 | /* End of tls-gnu.c */ |