Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
f9ba5e22 | 5 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
059ec3d9 PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
17c76198 | 8 | /* Copyright (c) Phil Pennock 2012 */ |
059ec3d9 | 9 | |
17c76198 PP |
10 | /* This file provides TLS/SSL support for Exim using the GnuTLS library, |
11 | one of the available supported implementations. This file is #included into | |
12 | tls.c when USE_GNUTLS has been set. | |
059ec3d9 | 13 | |
17c76198 PP |
14 | The code herein is a revamp of GnuTLS integration using the current APIs; the |
15 | original tls-gnu.c was based on a patch which was contributed by Nikos | |
6aa6fc9c | 16 | Mavrogiannopoulos. The revamp is partially a rewrite, partially cut&paste as |
17c76198 | 17 | appropriate. |
059ec3d9 | 18 | |
17c76198 PP |
19 | APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, |
20 | which is not widely deployed by OS vendors. Will note issues below, which may | |
21 | assist in updating the code in the future. Another sources of hints is | |
22 | mod_gnutls for Apache (SNI callback registration and handling). | |
059ec3d9 | 23 | |
17c76198 PP |
24 | Keeping client and server variables more split than before and is currently |
25 | the norm, in anticipation of TLS in ACL callouts. | |
059ec3d9 | 26 | |
17c76198 PP |
27 | I wanted to switch to gnutls_certificate_set_verify_function() so that |
28 | certificate rejection could happen during handshake where it belongs, rather | |
29 | than being dropped afterwards, but that was introduced in 2.10.0 and Debian | |
30 | (6.0.5) is still on 2.8.6. So for now we have to stick with sub-par behaviour. | |
059ec3d9 | 31 | |
17c76198 PP |
32 | (I wasn't looking for libraries quite that old, when updating to get rid of |
33 | compiler warnings of deprecated APIs. If it turns out that a lot of the rest | |
34 | require current GnuTLS, then we'll drop support for the ancient libraries). | |
35 | */ | |
b5aea5e1 | 36 | |
17c76198 PP |
37 | #include <gnutls/gnutls.h> |
38 | /* needed for cert checks in verification and DN extraction: */ | |
39 | #include <gnutls/x509.h> | |
40 | /* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ | |
41 | #include <gnutls/crypto.h> | |
a5f239e4 PP |
42 | /* needed to disable PKCS11 autoload unless requested */ |
43 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 | |
44 | # include <gnutls/pkcs11.h> | |
76075bb5 | 45 | # define SUPPORT_PARAM_TO_PK_BITS |
a5f239e4 | 46 | #endif |
7e07527a JH |
47 | #if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) |
48 | # warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" | |
49 | # define DISABLE_OCSP | |
50 | #endif | |
0cbf2b82 | 51 | #if GNUTLS_VERSION_NUMBER < 0x020a00 && !defined(DISABLE_EVENT) |
774ef2d7 | 52 | # warning "GnuTLS library version too old; tls:cert event unsupported" |
0cbf2b82 | 53 | # define DISABLE_EVENT |
a7538db1 | 54 | #endif |
a7fec7a7 JH |
55 | #if GNUTLS_VERSION_NUMBER >= 0x030306 |
56 | # define SUPPORT_CA_DIR | |
57 | #else | |
58 | # undef SUPPORT_CA_DIR | |
59 | #endif | |
11a04b5a | 60 | #if GNUTLS_VERSION_NUMBER >= 0x030014 |
cb1d7830 JH |
61 | # define SUPPORT_SYSDEFAULT_CABUNDLE |
62 | #endif | |
925ac8e4 JH |
63 | #if GNUTLS_VERSION_NUMBER >= 0x030109 |
64 | # define SUPPORT_CORK | |
65 | #endif | |
47195144 JH |
66 | #if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP) |
67 | # define SUPPORT_SRV_OCSP_STACK | |
68 | #endif | |
c0635b6d JH |
69 | |
70 | #ifdef SUPPORT_DANE | |
71 | # if GNUTLS_VERSION_NUMBER >= 0x030000 | |
72 | # define DANESSL_USAGE_DANE_TA 2 | |
73 | # define DANESSL_USAGE_DANE_EE 3 | |
74 | # else | |
75 | # error GnuTLS version too early for DANE | |
76 | # endif | |
77 | # if GNUTLS_VERSION_NUMBER < 0x999999 | |
78 | # define GNUTLS_BROKEN_DANE_VALIDATION | |
79 | # endif | |
899b8bbc | 80 | #endif |
7e07527a | 81 | |
f2de3a33 | 82 | #ifndef DISABLE_OCSP |
2b4a568d JH |
83 | # include <gnutls/ocsp.h> |
84 | #endif | |
899b8bbc JH |
85 | #ifdef SUPPORT_DANE |
86 | # include <gnutls/dane.h> | |
87 | #endif | |
059ec3d9 | 88 | |
17c76198 | 89 | /* GnuTLS 2 vs 3 |
059ec3d9 | 90 | |
17c76198 PP |
91 | GnuTLS 3 only: |
92 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 93 | |
17c76198 PP |
94 | Changes: |
95 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
96 | */ | |
059ec3d9 | 97 | |
17c76198 | 98 | /* Local static variables for GnuTLS */ |
059ec3d9 | 99 | |
17c76198 | 100 | /* Values for verify_requirement */ |
059ec3d9 | 101 | |
e51c7be2 | 102 | enum peer_verify_requirement |
899b8bbc | 103 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED, VERIFY_DANE }; |
059ec3d9 | 104 | |
17c76198 PP |
105 | /* This holds most state for server or client; with this, we can set up an |
106 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
107 | over the TLS variables available for expansion. | |
059ec3d9 | 108 | |
17c76198 PP |
109 | Some of these correspond to variables in globals.c; those variables will |
110 | be set to point to content in one of these instances, as appropriate for | |
111 | the stage of the process lifetime. | |
059ec3d9 | 112 | |
389ca47a | 113 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 114 | */ |
059ec3d9 | 115 | |
17c76198 | 116 | typedef struct exim_gnutls_state { |
9d1c15ef | 117 | gnutls_session_t session; |
17c76198 | 118 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 119 | gnutls_priority_t priority_cache; |
17c76198 | 120 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
121 | int fd_in; |
122 | int fd_out; | |
123 | BOOL peer_cert_verified; | |
899b8bbc | 124 | BOOL peer_dane_verified; |
9d1c15ef JH |
125 | BOOL trigger_sni_changes; |
126 | BOOL have_set_peerdn; | |
17c76198 | 127 | const struct host_item *host; |
9d1c15ef JH |
128 | gnutls_x509_crt_t peercert; |
129 | uschar *peerdn; | |
130 | uschar *ciphersuite; | |
131 | uschar *received_sni; | |
17c76198 PP |
132 | |
133 | const uschar *tls_certificate; | |
134 | const uschar *tls_privatekey; | |
135 | const uschar *tls_sni; /* client send only, not received */ | |
136 | const uschar *tls_verify_certificates; | |
137 | const uschar *tls_crl; | |
138 | const uschar *tls_require_ciphers; | |
e51c7be2 | 139 | |
17c76198 PP |
140 | uschar *exp_tls_certificate; |
141 | uschar *exp_tls_privatekey; | |
17c76198 PP |
142 | uschar *exp_tls_verify_certificates; |
143 | uschar *exp_tls_crl; | |
144 | uschar *exp_tls_require_ciphers; | |
55414b25 | 145 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 146 | #ifndef DISABLE_EVENT |
a7538db1 JH |
147 | uschar *event_action; |
148 | #endif | |
899b8bbc JH |
149 | #ifdef SUPPORT_DANE |
150 | char * const * dane_data; | |
151 | const int * dane_data_len; | |
152 | #endif | |
17c76198 | 153 | |
389ca47a | 154 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 155 | |
17c76198 PP |
156 | uschar *xfer_buffer; |
157 | int xfer_buffer_lwm; | |
158 | int xfer_buffer_hwm; | |
8b77d27a JH |
159 | BOOL xfer_eof; /*XXX never gets set! */ |
160 | BOOL xfer_error; | |
17c76198 PP |
161 | } exim_gnutls_state_st; |
162 | ||
163 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
f2ed27cf JH |
164 | .session = NULL, |
165 | .x509_cred = NULL, | |
166 | .priority_cache = NULL, | |
167 | .verify_requirement = VERIFY_NONE, | |
168 | .fd_in = -1, | |
169 | .fd_out = -1, | |
170 | .peer_cert_verified = FALSE, | |
899b8bbc | 171 | .peer_dane_verified = FALSE, |
f2ed27cf JH |
172 | .trigger_sni_changes =FALSE, |
173 | .have_set_peerdn = FALSE, | |
174 | .host = NULL, | |
175 | .peercert = NULL, | |
176 | .peerdn = NULL, | |
177 | .ciphersuite = NULL, | |
178 | .received_sni = NULL, | |
179 | ||
180 | .tls_certificate = NULL, | |
181 | .tls_privatekey = NULL, | |
182 | .tls_sni = NULL, | |
183 | .tls_verify_certificates = NULL, | |
184 | .tls_crl = NULL, | |
185 | .tls_require_ciphers =NULL, | |
186 | ||
187 | .exp_tls_certificate = NULL, | |
188 | .exp_tls_privatekey = NULL, | |
189 | .exp_tls_verify_certificates = NULL, | |
190 | .exp_tls_crl = NULL, | |
191 | .exp_tls_require_ciphers = NULL, | |
f2ed27cf | 192 | .exp_tls_verify_cert_hostnames = NULL, |
0cbf2b82 | 193 | #ifndef DISABLE_EVENT |
f2ed27cf | 194 | .event_action = NULL, |
e51c7be2 | 195 | #endif |
f2ed27cf JH |
196 | .tlsp = NULL, |
197 | ||
198 | .xfer_buffer = NULL, | |
199 | .xfer_buffer_lwm = 0, | |
200 | .xfer_buffer_hwm = 0, | |
8b77d27a JH |
201 | .xfer_eof = FALSE, |
202 | .xfer_error = FALSE, | |
17c76198 | 203 | }; |
83da1223 | 204 | |
17c76198 PP |
205 | /* Not only do we have our own APIs which don't pass around state, assuming |
206 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
207 | for callbacks, or as part of the session, so we have to keep a "this is the | |
208 | context we're currently dealing with" pointer and rely upon being | |
209 | single-threaded to keep from processing data on an inbound TLS connection while | |
210 | talking to another TLS connection for an outbound check. This does mean that | |
211 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
212 | second connection. |
213 | XXX But see gnutls_session_get_ptr() | |
214 | */ | |
059ec3d9 | 215 | |
17c76198 | 216 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 217 | |
17c76198 PP |
218 | /* dh_params are initialised once within the lifetime of a process using TLS; |
219 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
220 | don't want to repeat this. */ | |
83da1223 | 221 | |
17c76198 | 222 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 223 | |
17c76198 | 224 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 225 | |
17c76198 | 226 | static const int ssl_session_timeout = 200; |
059ec3d9 | 227 | |
17c76198 | 228 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 229 | |
17c76198 | 230 | /* Guard library core initialisation */ |
83da1223 | 231 | |
17c76198 | 232 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 233 | |
4fb7df6d | 234 | #ifndef DISABLE_OCSP |
9196d5bf | 235 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 236 | #endif |
9196d5bf | 237 | |
059ec3d9 | 238 | |
17c76198 PP |
239 | /* ------------------------------------------------------------------------ */ |
240 | /* macros */ | |
83da1223 | 241 | |
17c76198 | 242 | #define MAX_HOST_LEN 255 |
83da1223 | 243 | |
17c76198 PP |
244 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
245 | the library logging; a value less than 0 disables the calls to set up logging | |
ef9da2ee JH |
246 | callbacks. Possibly GNuTLS also looks for an environment variable |
247 | "GNUTLS_DEBUG_LEVEL". */ | |
2c17bb02 | 248 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 249 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 250 | #endif |
83da1223 | 251 | |
2c17bb02 | 252 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 253 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 254 | #endif |
83da1223 | 255 | |
af3498d6 PP |
256 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
257 | can ask for a bit-strength. Without that, we stick to the constant we had | |
258 | before, for now. */ | |
2c17bb02 | 259 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 260 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 261 | #endif |
af3498d6 | 262 | |
47195144 JH |
263 | #define exim_gnutls_err_check(rc, Label) do { \ |
264 | if ((rc) != GNUTLS_E_SUCCESS) \ | |
cf0c6164 JH |
265 | return tls_error((Label), gnutls_strerror(rc), host, errstr); \ |
266 | } while (0) | |
059ec3d9 | 267 | |
cf0c6164 JH |
268 | #define expand_check_tlsvar(Varname, errstr) \ |
269 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 270 | |
17c76198 | 271 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
272 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
273 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
274 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
275 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
276 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
277 | * isn't available sometimes, so this needs to become a conditional | |
278 | * compilation; the sanest way to deal with this being a problem on | |
279 | * older OSes is to block it in the Local/Makefile with this compiler | |
280 | * definition */ | |
e51c7be2 JH |
281 | # ifndef AVOID_GNUTLS_PKCS11 |
282 | # define HAVE_GNUTLS_PKCS11 | |
283 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 284 | #endif |
83da1223 | 285 | |
af3498d6 PP |
286 | |
287 | ||
288 | ||
289 | /* ------------------------------------------------------------------------ */ | |
290 | /* Callback declarations */ | |
291 | ||
292 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
293 | static void exim_gnutls_logger_cb(int level, const char *message); | |
294 | #endif | |
295 | ||
296 | static int exim_sni_handling_cb(gnutls_session_t session); | |
297 | ||
f2de3a33 | 298 | #ifndef DISABLE_OCSP |
44662487 JH |
299 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
300 | gnutls_datum_t * ocsp_response); | |
301 | #endif | |
af3498d6 PP |
302 | |
303 | ||
304 | ||
17c76198 PP |
305 | /* ------------------------------------------------------------------------ */ |
306 | /* Static functions */ | |
059ec3d9 PH |
307 | |
308 | /************************************************* | |
309 | * Handle TLS error * | |
310 | *************************************************/ | |
311 | ||
312 | /* Called from lots of places when errors occur before actually starting to do | |
313 | the TLS handshake, that is, while the session is still in clear. Always returns | |
314 | DEFER for a server and FAIL for a client so that most calls can use "return | |
315 | tls_error(...)" to do this processing and then give an appropriate return. A | |
316 | single function is used for both server and client, because it is called from | |
317 | some shared functions. | |
318 | ||
319 | Argument: | |
320 | prefix text to include in the logged error | |
7199e1ee TF |
321 | msg additional error string (may be NULL) |
322 | usually obtained from gnutls_strerror() | |
17c76198 PP |
323 | host NULL if setting up a server; |
324 | the connected host if setting up a client | |
cf0c6164 | 325 | errstr pointer to returned error string |
059ec3d9 PH |
326 | |
327 | Returns: OK/DEFER/FAIL | |
328 | */ | |
329 | ||
330 | static int | |
cf0c6164 JH |
331 | tls_error(const uschar *prefix, const char *msg, const host_item *host, |
332 | uschar ** errstr) | |
059ec3d9 | 333 | { |
cf0c6164 JH |
334 | if (errstr) |
335 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); | |
336 | return host ? FAIL : DEFER; | |
059ec3d9 PH |
337 | } |
338 | ||
339 | ||
340 | ||
17c76198 | 341 | |
059ec3d9 | 342 | /************************************************* |
17c76198 | 343 | * Deal with logging errors during I/O * |
059ec3d9 PH |
344 | *************************************************/ |
345 | ||
17c76198 | 346 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 347 | |
17c76198 PP |
348 | Argument: |
349 | state the current GnuTLS exim state container | |
350 | rc the GnuTLS error code, or 0 if it's a local error | |
351 | when text identifying read or write | |
352 | text local error text when ec is 0 | |
059ec3d9 | 353 | |
17c76198 | 354 | Returns: nothing |
059ec3d9 PH |
355 | */ |
356 | ||
17c76198 PP |
357 | static void |
358 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 359 | { |
cf0c6164 JH |
360 | const char * msg; |
361 | uschar * errstr; | |
059ec3d9 | 362 | |
17c76198 PP |
363 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
364 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
365 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
366 | else | |
367 | msg = gnutls_strerror(rc); | |
059ec3d9 | 368 | |
cf0c6164 JH |
369 | (void) tls_error(when, msg, state->host, &errstr); |
370 | ||
371 | if (state->host) | |
372 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
373 | state->host->name, state->host->address, errstr); | |
374 | else | |
375 | { | |
376 | uschar * conn_info = smtp_get_connection_info(); | |
377 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
378 | /* I'd like to get separated H= here, but too hard for now */ | |
379 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
380 | } | |
17c76198 | 381 | } |
059ec3d9 | 382 | |
059ec3d9 | 383 | |
059ec3d9 | 384 | |
059ec3d9 | 385 | |
17c76198 PP |
386 | /************************************************* |
387 | * Set various Exim expansion vars * | |
388 | *************************************************/ | |
059ec3d9 | 389 | |
e51c7be2 JH |
390 | #define exim_gnutls_cert_err(Label) \ |
391 | do \ | |
392 | { \ | |
393 | if (rc != GNUTLS_E_SUCCESS) \ | |
394 | { \ | |
395 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
396 | (Label), gnutls_strerror(rc)); \ | |
397 | return rc; \ | |
398 | } \ | |
399 | } while (0) | |
9d1c15ef JH |
400 | |
401 | static int | |
27f19eb4 | 402 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
403 | { |
404 | int rc; | |
405 | ||
406 | rc = gnutls_x509_crt_init(crtp); | |
407 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
408 | ||
409 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
410 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
411 | ||
412 | return rc; | |
413 | } | |
414 | ||
415 | #undef exim_gnutls_cert_err | |
416 | ||
417 | ||
17c76198 PP |
418 | /* We set various Exim global variables from the state, once a session has |
419 | been established. With TLS callouts, may need to change this to stack | |
420 | variables, or just re-call it with the server state after client callout | |
421 | has finished. | |
059ec3d9 | 422 | |
9d1c15ef | 423 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
424 | |
425 | Sets: | |
426 | tls_active fd | |
427 | tls_bits strength indicator | |
428 | tls_certificate_verified bool indicator | |
429 | tls_channelbinding_b64 for some SASL mechanisms | |
430 | tls_cipher a string | |
9d1c15ef | 431 | tls_peercert pointer to library internal |
17c76198 PP |
432 | tls_peerdn a string |
433 | tls_sni a (UTF-8) string | |
9d1c15ef | 434 | tls_ourcert pointer to library internal |
17c76198 PP |
435 | |
436 | Argument: | |
437 | state the relevant exim_gnutls_state_st * | |
438 | */ | |
439 | ||
440 | static void | |
9d1c15ef | 441 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 442 | { |
17c76198 | 443 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
444 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
445 | int old_pool; | |
446 | int rc; | |
447 | gnutls_datum_t channel; | |
448 | #endif | |
9d1c15ef | 449 | tls_support * tlsp = state->tlsp; |
17c76198 | 450 | |
9d1c15ef | 451 | tlsp->active = state->fd_out; |
17c76198 PP |
452 | |
453 | cipher = gnutls_cipher_get(state->session); | |
454 | /* returns size in "bytes" */ | |
9d1c15ef | 455 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 456 | |
9d1c15ef | 457 | tlsp->cipher = state->ciphersuite; |
17c76198 | 458 | |
817d9f57 | 459 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 460 | |
9d1c15ef | 461 | tlsp->certificate_verified = state->peer_cert_verified; |
899b8bbc JH |
462 | #ifdef SUPPORT_DANE |
463 | tlsp->dane_verified = state->peer_dane_verified; | |
464 | #endif | |
059ec3d9 | 465 | |
17c76198 PP |
466 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
467 | only available for use for authenticators while this TLS session is running. */ | |
468 | ||
469 | tls_channelbinding_b64 = NULL; | |
470 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
471 | channel.data = NULL; | |
472 | channel.size = 0; | |
473 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
474 | if (rc) { | |
475 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
476 | } else { | |
477 | old_pool = store_pool; | |
478 | store_pool = POOL_PERM; | |
f4d091fb | 479 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
480 | store_pool = old_pool; |
481 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
482 | } | |
483 | #endif | |
484 | ||
9d1c15ef JH |
485 | /* peercert is set in peer_status() */ |
486 | tlsp->peerdn = state->peerdn; | |
487 | tlsp->sni = state->received_sni; | |
488 | ||
489 | /* record our certificate */ | |
490 | { | |
27f19eb4 | 491 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
492 | gnutls_x509_crt_t crt; |
493 | ||
494 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
495 | } | |
059ec3d9 PH |
496 | } |
497 | ||
498 | ||
499 | ||
17c76198 | 500 | |
059ec3d9 | 501 | /************************************************* |
575643cd | 502 | * Setup up DH parameters * |
059ec3d9 PH |
503 | *************************************************/ |
504 | ||
575643cd | 505 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
506 | be re-generated every so often, depending on security policy. What we do is to |
507 | keep these parameters in a file in the spool directory. If the file does not | |
508 | exist, we generate them. This means that it is easy to cause a regeneration. | |
509 | ||
510 | The new file is written as a temporary file and renamed, so that an incomplete | |
511 | file is never present. If two processes both compute some new parameters, you | |
512 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
513 | prevent this. | |
514 | ||
059ec3d9 PH |
515 | Returns: OK/DEFER/FAIL |
516 | */ | |
517 | ||
518 | static int | |
cf0c6164 | 519 | init_server_dh(uschar ** errstr) |
059ec3d9 | 520 | { |
17c76198 PP |
521 | int fd, rc; |
522 | unsigned int dh_bits; | |
27f19eb4 | 523 | gnutls_datum_t m; |
a799883d PP |
524 | uschar filename_buf[PATH_MAX]; |
525 | uschar *filename = NULL; | |
17c76198 | 526 | size_t sz; |
a799883d PP |
527 | uschar *exp_tls_dhparam; |
528 | BOOL use_file_in_spool = FALSE; | |
529 | BOOL use_fixed_file = FALSE; | |
17c76198 | 530 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 531 | |
17c76198 | 532 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 533 | |
17c76198 | 534 | rc = gnutls_dh_params_init(&dh_server_params); |
47195144 | 535 | exim_gnutls_err_check(rc, US"gnutls_dh_params_init"); |
059ec3d9 | 536 | |
a799883d PP |
537 | m.data = NULL; |
538 | m.size = 0; | |
539 | ||
cf0c6164 | 540 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
541 | return DEFER; |
542 | ||
543 | if (!exp_tls_dhparam) | |
544 | { | |
545 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
546 | m.data = US std_dh_prime_default(); | |
547 | m.size = Ustrlen(m.data); | |
548 | } | |
549 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
550 | use_file_in_spool = TRUE; | |
551 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
552 | { | |
553 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
554 | return OK; | |
555 | } | |
556 | else if (exp_tls_dhparam[0] != '/') | |
557 | { | |
f5d25c2b | 558 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
cf0c6164 | 559 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); |
a799883d PP |
560 | m.size = Ustrlen(m.data); |
561 | } | |
562 | else | |
563 | { | |
564 | use_fixed_file = TRUE; | |
565 | filename = exp_tls_dhparam; | |
566 | } | |
567 | ||
568 | if (m.data) | |
569 | { | |
570 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
47195144 | 571 | exim_gnutls_err_check(rc, US"gnutls_dh_params_import_pkcs3"); |
a799883d PP |
572 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); |
573 | return OK; | |
574 | } | |
575 | ||
af3498d6 PP |
576 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
577 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
578 | different filename and ensure we have sufficient bits. */ |
579 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
580 | if (!dh_bits) | |
cf0c6164 | 581 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 582 | DEBUG(D_tls) |
b34fc30c | 583 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
584 | dh_bits); |
585 | #else | |
586 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
587 | DEBUG(D_tls) | |
588 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
589 | dh_bits); | |
590 | #endif | |
059ec3d9 | 591 | |
3375e053 PP |
592 | /* Some clients have hard-coded limits. */ |
593 | if (dh_bits > tls_dh_max_bits) | |
594 | { | |
595 | DEBUG(D_tls) | |
596 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
597 | tls_dh_max_bits); | |
598 | dh_bits = tls_dh_max_bits; | |
599 | } | |
600 | ||
a799883d PP |
601 | if (use_file_in_spool) |
602 | { | |
603 | if (!string_format(filename_buf, sizeof(filename_buf), | |
604 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 605 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
606 | filename = filename_buf; |
607 | } | |
059ec3d9 | 608 | |
b5aea5e1 | 609 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 610 | parameters. */ |
059ec3d9 | 611 | |
f5d25c2b | 612 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 613 | { |
b5aea5e1 | 614 | struct stat statbuf; |
17c76198 PP |
615 | FILE *fp; |
616 | int saved_errno; | |
617 | ||
618 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
619 | { | |
620 | saved_errno = errno; | |
621 | (void)close(fd); | |
cf0c6164 | 622 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
623 | } |
624 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
625 | { |
626 | (void)close(fd); | |
cf0c6164 | 627 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 628 | } |
40c90bca | 629 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
630 | { |
631 | saved_errno = errno; | |
632 | (void)close(fd); | |
633 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
cf0c6164 | 634 | strerror(saved_errno), NULL, errstr); |
b5aea5e1 | 635 | } |
059ec3d9 | 636 | |
b5aea5e1 | 637 | m.size = statbuf.st_size; |
40c90bca | 638 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
639 | { |
640 | fclose(fp); | |
cf0c6164 | 641 | return tls_error(US"malloc failed", strerror(errno), NULL, errstr); |
17c76198 | 642 | } |
40c90bca | 643 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
644 | { |
645 | saved_errno = errno; | |
646 | fclose(fp); | |
647 | free(m.data); | |
cf0c6164 | 648 | return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
649 | } |
650 | fclose(fp); | |
b5aea5e1 | 651 | |
17c76198 | 652 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 653 | free(m.data); |
47195144 | 654 | exim_gnutls_err_check(rc, US"gnutls_dh_params_import_pkcs3"); |
17c76198 | 655 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); |
b5aea5e1 PH |
656 | } |
657 | ||
658 | /* If the file does not exist, fall through to compute new data and cache it. | |
659 | If there was any other opening error, it is serious. */ | |
660 | ||
182ad5cf PH |
661 | else if (errno == ENOENT) |
662 | { | |
17c76198 | 663 | rc = -1; |
182ad5cf | 664 | DEBUG(D_tls) |
17c76198 | 665 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
666 | } |
667 | else | |
17c76198 | 668 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 669 | NULL, NULL, errstr); |
b5aea5e1 PH |
670 | |
671 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
672 | is not useful. One particular case of this is when upgrading from an older | |
673 | release of Exim in which the data was stored in a different format. We don't | |
674 | try to be clever and support both formats; we just regenerate new data in this | |
675 | case. */ | |
676 | ||
17c76198 | 677 | if (rc < 0) |
b5aea5e1 | 678 | { |
17c76198 | 679 | uschar *temp_fn; |
201f5254 | 680 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 681 | |
17c76198 PP |
682 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
683 | return tls_error(US"Filename too long to generate replacement", | |
cf0c6164 | 684 | CS filename, NULL, errstr); |
059ec3d9 | 685 | |
17c76198 | 686 | temp_fn = string_copy(US "%s.XXXXXXX"); |
f5d25c2b | 687 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
cf0c6164 | 688 | return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); |
059ec3d9 PH |
689 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
690 | ||
201f5254 PP |
691 | /* GnuTLS overshoots! |
692 | * If we ask for 2236, we might get 2237 or more. | |
693 | * But there's no way to ask GnuTLS how many bits there really are. | |
694 | * We can ask how many bits were used in a TLS session, but that's it! | |
695 | * The prime itself is hidden behind too much abstraction. | |
696 | * So we ask for less, and proceed on a wing and a prayer. | |
697 | * First attempt, subtracted 3 for 2233 and got 2240. | |
698 | */ | |
cae6e576 | 699 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
700 | { |
701 | dh_bits_gen = dh_bits - 10; | |
702 | DEBUG(D_tls) | |
703 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
704 | dh_bits_gen); | |
705 | } | |
706 | ||
707 | DEBUG(D_tls) | |
708 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
709 | dh_bits_gen); | |
710 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
47195144 | 711 | exim_gnutls_err_check(rc, US"gnutls_dh_params_generate2"); |
17c76198 PP |
712 | |
713 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
714 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
715 | sample apps handle this. */ | |
716 | ||
717 | sz = 0; | |
718 | m.data = NULL; | |
719 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
720 | m.data, &sz); | |
721 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
47195144 | 722 | exim_gnutls_err_check(rc, US"gnutls_dh_params_export_pkcs3(NULL) sizing"); |
17c76198 | 723 | m.size = sz; |
40c90bca | 724 | if (!(m.data = malloc(m.size))) |
cf0c6164 | 725 | return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); |
40c90bca | 726 | |
1f00591e | 727 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 728 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 729 | m.data, &sz); |
17c76198 PP |
730 | if (rc != GNUTLS_E_SUCCESS) |
731 | { | |
732 | free(m.data); | |
47195144 | 733 | exim_gnutls_err_check(rc, US"gnutls_dh_params_export_pkcs3() real"); |
17c76198 | 734 | } |
1f00591e | 735 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 736 | |
f5d25c2b | 737 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 PP |
738 | { |
739 | free(m.data); | |
740 | return tls_error(US"TLS cache write D-H params failed", | |
cf0c6164 | 741 | strerror(errno), NULL, errstr); |
17c76198 | 742 | } |
b5aea5e1 | 743 | free(m.data); |
f5d25c2b | 744 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
17c76198 | 745 | return tls_error(US"TLS cache write D-H params final newline failed", |
cf0c6164 | 746 | strerror(errno), NULL, errstr); |
17c76198 | 747 | |
f5d25c2b | 748 | if ((rc = close(fd))) |
cf0c6164 | 749 | return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); |
059ec3d9 | 750 | |
17c76198 PP |
751 | if (Urename(temp_fn, filename) < 0) |
752 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
cf0c6164 | 753 | temp_fn, filename), strerror(errno), NULL, errstr); |
059ec3d9 | 754 | |
17c76198 | 755 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
756 | } |
757 | ||
17c76198 | 758 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
759 | return OK; |
760 | } | |
761 | ||
762 | ||
763 | ||
764 | ||
23bb6982 JH |
765 | /* Create and install a selfsigned certificate, for use in server mode */ |
766 | ||
767 | static int | |
cf0c6164 | 768 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
769 | { |
770 | gnutls_x509_crt_t cert = NULL; | |
771 | time_t now; | |
772 | gnutls_x509_privkey_t pkey = NULL; | |
773 | const uschar * where; | |
774 | int rc; | |
775 | ||
776 | where = US"initialising pkey"; | |
777 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
778 | ||
779 | where = US"initialising cert"; | |
780 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
781 | ||
782 | where = US"generating pkey"; | |
783 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 784 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
23bb6982 | 785 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), |
76075bb5 JH |
786 | #else |
787 | 1024, | |
788 | #endif | |
789 | 0))) | |
23bb6982 JH |
790 | goto err; |
791 | ||
792 | where = US"configuring cert"; | |
1613fd68 | 793 | now = 1; |
23bb6982 JH |
794 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) |
795 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
796 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
797 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
798 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
799 | ||
800 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
801 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
802 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
803 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
804 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
805 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
806 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
807 | ) | |
808 | goto err; | |
809 | ||
810 | where = US"signing cert"; | |
811 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
812 | ||
813 | where = US"installing selfsign cert"; | |
814 | /* Since: 2.4.0 */ | |
815 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
816 | goto err; | |
817 | ||
818 | rc = OK; | |
819 | ||
820 | out: | |
821 | if (cert) gnutls_x509_crt_deinit(cert); | |
822 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
823 | return rc; | |
824 | ||
825 | err: | |
cf0c6164 | 826 | rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); |
23bb6982 JH |
827 | goto out; |
828 | } | |
829 | ||
830 | ||
831 | ||
832 | ||
47195144 JH |
833 | /* Add certificate and key, from files. |
834 | ||
835 | Return: | |
836 | Zero or negative: good. Negate value for certificate index if < 0. | |
837 | Greater than zero: FAIL or DEFER code. | |
838 | */ | |
839 | ||
ba86e143 JH |
840 | static int |
841 | tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, | |
842 | uschar * certfile, uschar * keyfile, uschar ** errstr) | |
843 | { | |
844 | int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, | |
845 | CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); | |
47195144 JH |
846 | if (rc < 0) |
847 | return tls_error( | |
848 | string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile), | |
849 | gnutls_strerror(rc), host, errstr); | |
850 | return -rc; | |
ba86e143 JH |
851 | } |
852 | ||
853 | ||
059ec3d9 | 854 | /************************************************* |
17c76198 | 855 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
856 | *************************************************/ |
857 | ||
17c76198 PP |
858 | /* Called from both server and client code, via tls_init(), and also from |
859 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
860 | ||
861 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
862 | ||
863 | The callback should not call us unless state->trigger_sni_changes is true, | |
864 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
865 | |
866 | Arguments: | |
17c76198 | 867 | state exim_gnutls_state_st * |
cf0c6164 | 868 | errstr error string pointer |
059ec3d9 PH |
869 | |
870 | Returns: OK/DEFER/FAIL | |
871 | */ | |
872 | ||
873 | static int | |
ba86e143 | 874 | tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 875 | { |
1365611d | 876 | struct stat statbuf; |
059ec3d9 | 877 | int rc; |
17c76198 PP |
878 | const host_item *host = state->host; /* macro should be reconsidered? */ |
879 | uschar *saved_tls_certificate = NULL; | |
880 | uschar *saved_tls_privatekey = NULL; | |
881 | uschar *saved_tls_verify_certificates = NULL; | |
882 | uschar *saved_tls_crl = NULL; | |
883 | int cert_count; | |
884 | ||
885 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 886 | if (!host) /* server */ |
17c76198 PP |
887 | if (!state->received_sni) |
888 | { | |
ba86e143 JH |
889 | if ( state->tls_certificate |
890 | && ( Ustrstr(state->tls_certificate, US"tls_sni") | |
891 | || Ustrstr(state->tls_certificate, US"tls_in_sni") | |
892 | || Ustrstr(state->tls_certificate, US"tls_out_sni") | |
893 | ) ) | |
17c76198 PP |
894 | { |
895 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
896 | state->trigger_sni_changes = TRUE; | |
897 | } | |
898 | } | |
899 | else | |
900 | { | |
1365611d | 901 | /* useful for debugging */ |
17c76198 PP |
902 | saved_tls_certificate = state->exp_tls_certificate; |
903 | saved_tls_privatekey = state->exp_tls_privatekey; | |
904 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
905 | saved_tls_crl = state->exp_tls_crl; | |
906 | } | |
059ec3d9 | 907 | |
1365611d | 908 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
47195144 JH |
909 | exim_gnutls_err_check(rc, US"gnutls_certificate_allocate_credentials"); |
910 | ||
911 | #ifdef SUPPORT_SRV_OCSP_STACK | |
912 | gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2); | |
913 | #endif | |
1365611d | 914 | |
17c76198 PP |
915 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
916 | state members, assuming consistent naming; and expand_check() returns | |
917 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 918 | |
17c76198 PP |
919 | /* check if we at least have a certificate, before doing expensive |
920 | D-H generation. */ | |
059ec3d9 | 921 | |
cf0c6164 | 922 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 923 | return DEFER; |
059ec3d9 | 924 | |
17c76198 | 925 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 926 | |
23bb6982 JH |
927 | if ( !state->exp_tls_certificate |
928 | || !*state->exp_tls_certificate | |
929 | ) | |
2b4a568d | 930 | if (!host) |
cf0c6164 | 931 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
932 | else |
933 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 934 | |
cf0c6164 | 935 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
936 | return DEFER; |
937 | ||
17c76198 PP |
938 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
939 | ||
940 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 941 | { |
17c76198 PP |
942 | state->tls_privatekey = state->tls_certificate; |
943 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 944 | } |
c91535f3 | 945 | |
059ec3d9 | 946 | |
17c76198 | 947 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
948 | { |
949 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
950 | state->exp_tls_certificate, state->exp_tls_privatekey); |
951 | ||
952 | if (state->received_sni) | |
23bb6982 JH |
953 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
954 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
955 | ) | |
17c76198 | 956 | { |
b34fc30c | 957 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
958 | } |
959 | else | |
960 | { | |
b34fc30c | 961 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 962 | } |
059ec3d9 | 963 | |
ba86e143 JH |
964 | if (!host) /* server */ |
965 | { | |
966 | const uschar * clist = state->exp_tls_certificate; | |
967 | const uschar * klist = state->exp_tls_privatekey; | |
47195144 JH |
968 | const uschar * olist; |
969 | int csep = 0, ksep = 0, osep = 0, cnt = 0; | |
970 | uschar * cfile, * kfile, * ofile; | |
971 | ||
972 | #ifndef DISABLE_OCSP | |
973 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr)) | |
974 | return DEFER; | |
975 | olist = ofile; | |
976 | #endif | |
ba86e143 JH |
977 | |
978 | while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) | |
47195144 | 979 | |
ba86e143 JH |
980 | if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) |
981 | return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); | |
47195144 | 982 | else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr))) |
ba86e143 JH |
983 | return rc; |
984 | else | |
47195144 JH |
985 | { |
986 | int gnutls_cert_index = -rc; | |
ba86e143 | 987 | DEBUG(D_tls) debug_printf("TLS: cert/key %s registered\n", cfile); |
47195144 JH |
988 | |
989 | /* Set the OCSP stapling server info */ | |
990 | ||
991 | #ifndef DISABLE_OCSP | |
992 | if (tls_ocsp_file) | |
993 | if (gnutls_buggy_ocsp) | |
994 | { | |
995 | DEBUG(D_tls) | |
996 | debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
997 | } | |
998 | else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) | |
999 | { | |
1000 | /* Use the full callback method for stapling just to get | |
1001 | observability. More efficient would be to read the file once only, | |
1002 | if it never changed (due to SNI). Would need restart on file update, | |
1003 | or watch datestamp. */ | |
1004 | ||
1005 | # ifdef SUPPORT_SRV_OCSP_STACK | |
1006 | rc = gnutls_certificate_set_ocsp_status_request_function2( | |
1007 | state->x509_cred, gnutls_cert_index, | |
1008 | server_ocsp_stapling_cb, ofile); | |
1009 | ||
1010 | exim_gnutls_err_check(rc, | |
1011 | US"gnutls_certificate_set_ocsp_status_request_function2"); | |
1012 | # else | |
1013 | if (cnt++ > 0) | |
1014 | { | |
1015 | DEBUG(D_tls) | |
1016 | debug_printf("oops; multiple OCSP files not supported\n"); | |
1017 | break; | |
1018 | } | |
1019 | gnutls_certificate_set_ocsp_status_request_function( | |
1020 | state->x509_cred, server_ocsp_stapling_cb, ofile); | |
1021 | # endif | |
1022 | ||
1023 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); | |
1024 | } | |
1025 | else | |
1026 | DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); | |
1027 | #endif | |
1028 | } | |
ba86e143 JH |
1029 | } |
1030 | else | |
1031 | { | |
47195144 | 1032 | if (0 < (rc = tls_add_certfile(state, host, |
ba86e143 JH |
1033 | state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) |
1034 | return rc; | |
1035 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
1036 | } | |
1037 | ||
b34fc30c | 1038 | } /* tls_certificate */ |
059ec3d9 | 1039 | |
2b4a568d | 1040 | |
059ec3d9 PH |
1041 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
1042 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
1043 | error message is provided. However, if we just refrain from setting anything up | |
1044 | in that case, certificate verification fails, which seems to be the correct | |
1045 | behaviour. */ | |
1046 | ||
610ff438 | 1047 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 1048 | { |
cf0c6164 | 1049 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 1050 | return DEFER; |
610ff438 JH |
1051 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
1052 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1053 | state->exp_tls_verify_certificates = NULL; | |
1054 | #endif | |
17c76198 | 1055 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 1056 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 1057 | return DEFER; |
059ec3d9 | 1058 | |
1365611d PP |
1059 | if (!(state->exp_tls_verify_certificates && |
1060 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
1061 | { |
1062 | DEBUG(D_tls) | |
1365611d PP |
1063 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
1064 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 1065 | return OK; |
b34fc30c | 1066 | } |
1365611d | 1067 | } |
83e2f8a2 PP |
1068 | else |
1069 | { | |
1070 | DEBUG(D_tls) | |
1071 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
1072 | return OK; | |
1073 | } | |
17c76198 | 1074 | |
cb1d7830 JH |
1075 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
1076 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1077 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
1078 | else | |
1079 | #endif | |
1365611d | 1080 | { |
cb1d7830 JH |
1081 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
1082 | { | |
1083 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
1084 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
1085 | strerror(errno)); | |
1086 | return DEFER; | |
1087 | } | |
17c76198 | 1088 | |
a7fec7a7 | 1089 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1090 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1091 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1092 | other weirdness. The thing we really want to check is that it's not a | |
1093 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1094 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1095 | if (S_ISDIR(statbuf.st_mode)) |
1096 | { | |
1097 | DEBUG(D_tls) | |
1098 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1099 | state->exp_tls_verify_certificates); | |
1100 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1101 | "tls_verify_certificates \"%s\" is a directory", | |
1102 | state->exp_tls_verify_certificates); | |
1103 | return DEFER; | |
1104 | } | |
a7fec7a7 | 1105 | #endif |
059ec3d9 | 1106 | |
cb1d7830 JH |
1107 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1108 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1109 | |
cb1d7830 JH |
1110 | if (statbuf.st_size == 0) |
1111 | { | |
1112 | DEBUG(D_tls) | |
1113 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1114 | return OK; | |
1115 | } | |
059ec3d9 | 1116 | |
cb1d7830 | 1117 | cert_count = |
a7fec7a7 JH |
1118 | |
1119 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1120 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1121 | ? | |
1122 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1123 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1124 | : | |
a7fec7a7 | 1125 | #endif |
cb1d7830 JH |
1126 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1127 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1128 | } | |
a7fec7a7 | 1129 | |
1365611d PP |
1130 | if (cert_count < 0) |
1131 | { | |
1132 | rc = cert_count; | |
47195144 | 1133 | exim_gnutls_err_check(rc, US"setting certificate trust"); |
1365611d PP |
1134 | } |
1135 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1136 | |
5c8cda3a PP |
1137 | if (state->tls_crl && *state->tls_crl && |
1138 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1139 | { |
5c8cda3a PP |
1140 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1141 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1142 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1143 | if (cert_count < 0) | |
1365611d | 1144 | { |
5c8cda3a | 1145 | rc = cert_count; |
47195144 | 1146 | exim_gnutls_err_check(rc, US"gnutls_certificate_set_x509_crl_file"); |
1365611d | 1147 | } |
5c8cda3a | 1148 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1149 | } |
059ec3d9 | 1150 | |
059ec3d9 PH |
1151 | return OK; |
1152 | } | |
1153 | ||
1154 | ||
1155 | ||
1156 | ||
1365611d PP |
1157 | /************************************************* |
1158 | * Set X.509 state variables * | |
1159 | *************************************************/ | |
1160 | ||
1161 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1162 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1163 | structure. Which means various other non-re-expanded pieces of state | |
1164 | need to be re-set in the new struct, so the setting logic is pulled | |
1165 | out to this. | |
1166 | ||
1167 | Arguments: | |
1168 | state exim_gnutls_state_st * | |
cf0c6164 | 1169 | errstr error string pointer |
1365611d PP |
1170 | |
1171 | Returns: OK/DEFER/FAIL | |
1172 | */ | |
1173 | ||
1174 | static int | |
cf0c6164 | 1175 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1176 | { |
1177 | int rc; | |
1178 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1179 | ||
1180 | /* Create D-H parameters, or read them from the cache file. This function does | |
1181 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1182 | client-side params. */ | |
1183 | ||
1184 | if (!state->host) | |
1185 | { | |
1186 | if (!dh_server_params) | |
1187 | { | |
cf0c6164 | 1188 | rc = init_server_dh(errstr); |
1365611d PP |
1189 | if (rc != OK) return rc; |
1190 | } | |
1191 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1192 | } | |
1193 | ||
1194 | /* Link the credentials to the session. */ | |
1195 | ||
1196 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
47195144 | 1197 | exim_gnutls_err_check(rc, US"gnutls_credentials_set"); |
1365611d PP |
1198 | |
1199 | return OK; | |
1200 | } | |
1201 | ||
059ec3d9 | 1202 | /************************************************* |
17c76198 | 1203 | * Initialize for GnuTLS * |
059ec3d9 PH |
1204 | *************************************************/ |
1205 | ||
9196d5bf | 1206 | |
4fb7df6d JH |
1207 | #ifndef DISABLE_OCSP |
1208 | ||
9196d5bf JH |
1209 | static BOOL |
1210 | tls_is_buggy_ocsp(void) | |
1211 | { | |
1212 | const uschar * s; | |
1213 | uschar maj, mid, mic; | |
1214 | ||
1215 | s = CUS gnutls_check_version(NULL); | |
1216 | maj = atoi(CCS s); | |
1217 | if (maj == 3) | |
1218 | { | |
1219 | while (*s && *s != '.') s++; | |
1220 | mid = atoi(CCS ++s); | |
1221 | if (mid <= 2) | |
1222 | return TRUE; | |
1223 | else if (mid >= 5) | |
1224 | return FALSE; | |
1225 | else | |
1226 | { | |
1227 | while (*s && *s != '.') s++; | |
1228 | mic = atoi(CCS ++s); | |
1229 | return mic <= (mid == 3 ? 16 : 3); | |
1230 | } | |
1231 | } | |
1232 | return FALSE; | |
1233 | } | |
1234 | ||
4fb7df6d | 1235 | #endif |
9196d5bf JH |
1236 | |
1237 | ||
17c76198 PP |
1238 | /* Called from both server and client code. In the case of a server, errors |
1239 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1240 | |
1241 | Arguments: | |
17c76198 PP |
1242 | host connected host, if client; NULL if server |
1243 | certificate certificate file | |
1244 | privatekey private key file | |
1245 | sni TLS SNI to send, sometimes when client; else NULL | |
1246 | cas CA certs file | |
1247 | crl CRL file | |
1248 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1249 | caller_state returned state-info structure |
cf0c6164 | 1250 | errstr error string pointer |
059ec3d9 | 1251 | |
17c76198 | 1252 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1253 | */ |
1254 | ||
17c76198 PP |
1255 | static int |
1256 | tls_init( | |
1257 | const host_item *host, | |
1258 | const uschar *certificate, | |
1259 | const uschar *privatekey, | |
1260 | const uschar *sni, | |
1261 | const uschar *cas, | |
1262 | const uschar *crl, | |
1263 | const uschar *require_ciphers, | |
cf0c6164 JH |
1264 | exim_gnutls_state_st **caller_state, |
1265 | uschar ** errstr) | |
059ec3d9 | 1266 | { |
17c76198 PP |
1267 | exim_gnutls_state_st *state; |
1268 | int rc; | |
1269 | size_t sz; | |
1270 | const char *errpos; | |
1271 | uschar *p; | |
1272 | BOOL want_default_priorities; | |
1273 | ||
1274 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1275 | { |
17c76198 PP |
1276 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1277 | ||
a5f239e4 PP |
1278 | #ifdef HAVE_GNUTLS_PKCS11 |
1279 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1280 | which loads modules from a config file, which sounds good and may be wanted | |
1281 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1282 | environment variables are used and so breaks for users calling mailq. | |
1283 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1284 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1285 | { |
1286 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
47195144 | 1287 | exim_gnutls_err_check(rc, US"gnutls_pkcs11_init"); |
a5f239e4 PP |
1288 | } |
1289 | #endif | |
1290 | ||
17c76198 | 1291 | rc = gnutls_global_init(); |
47195144 | 1292 | exim_gnutls_err_check(rc, US"gnutls_global_init"); |
17c76198 PP |
1293 | |
1294 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1295 | DEBUG(D_tls) | |
059ec3d9 | 1296 | { |
17c76198 PP |
1297 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1298 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1299 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1300 | } |
17c76198 PP |
1301 | #endif |
1302 | ||
4fb7df6d JH |
1303 | #ifndef DISABLE_OCSP |
1304 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1305 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1306 | #endif |
9196d5bf | 1307 | |
17c76198 | 1308 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1309 | } |
059ec3d9 | 1310 | |
17c76198 PP |
1311 | if (host) |
1312 | { | |
1313 | state = &state_client; | |
1314 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1315 | state->tlsp = &tls_out; |
17c76198 PP |
1316 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1317 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1318 | } | |
1319 | else | |
1320 | { | |
1321 | state = &state_server; | |
1322 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1323 | state->tlsp = &tls_in; |
17c76198 PP |
1324 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1325 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1326 | } | |
47195144 | 1327 | exim_gnutls_err_check(rc, US"gnutls_init"); |
059ec3d9 | 1328 | |
17c76198 | 1329 | state->host = host; |
059ec3d9 | 1330 | |
17c76198 PP |
1331 | state->tls_certificate = certificate; |
1332 | state->tls_privatekey = privatekey; | |
5779e6aa | 1333 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1334 | state->tls_sni = sni; |
1335 | state->tls_verify_certificates = cas; | |
1336 | state->tls_crl = crl; | |
059ec3d9 | 1337 | |
17c76198 PP |
1338 | /* This handles the variables that might get re-expanded after TLS SNI; |
1339 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1340 | |
17c76198 PP |
1341 | DEBUG(D_tls) |
1342 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1343 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1344 | |
1365611d PP |
1345 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1346 | requires a new structure afterwards. */ | |
83da1223 | 1347 | |
cf0c6164 | 1348 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1349 | |
17c76198 PP |
1350 | /* set SNI in client, only */ |
1351 | if (host) | |
1352 | { | |
cf0c6164 | 1353 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1354 | return DEFER; |
0df4ab80 | 1355 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1356 | { |
1357 | DEBUG(D_tls) | |
0df4ab80 JH |
1358 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1359 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1360 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1361 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
47195144 | 1362 | exim_gnutls_err_check(rc, US"gnutls_server_name_set"); |
17c76198 PP |
1363 | } |
1364 | } | |
1365 | else if (state->tls_sni) | |
1366 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
ba86e143 | 1367 | "have an SNI set for a server [%s]\n", state->tls_sni); |
83da1223 | 1368 | |
17c76198 | 1369 | /* This is the priority string support, |
42bfef1e | 1370 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1371 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1372 | This was backwards incompatible, but means Exim no longer needs to track | |
1373 | all algorithms and provide string forms for them. */ | |
83da1223 | 1374 | |
17c76198 | 1375 | want_default_priorities = TRUE; |
83da1223 | 1376 | |
17c76198 | 1377 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1378 | { |
cf0c6164 | 1379 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1380 | return DEFER; |
1381 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1382 | { |
17c76198 PP |
1383 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1384 | state->exp_tls_require_ciphers); | |
1385 | ||
1386 | rc = gnutls_priority_init(&state->priority_cache, | |
1387 | CS state->exp_tls_require_ciphers, &errpos); | |
1388 | want_default_priorities = FALSE; | |
1389 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1390 | } |
1391 | } | |
17c76198 PP |
1392 | if (want_default_priorities) |
1393 | { | |
83e2f8a2 PP |
1394 | DEBUG(D_tls) |
1395 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1396 | exim_default_gnutls_priority); | |
17c76198 PP |
1397 | rc = gnutls_priority_init(&state->priority_cache, |
1398 | exim_default_gnutls_priority, &errpos); | |
1399 | p = US exim_default_gnutls_priority; | |
1400 | } | |
83da1223 | 1401 | |
47195144 | 1402 | exim_gnutls_err_check(rc, string_sprintf( |
17c76198 PP |
1403 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", |
1404 | p, errpos - CS p, errpos)); | |
1405 | ||
1406 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
47195144 | 1407 | exim_gnutls_err_check(rc, US"gnutls_priority_set"); |
17c76198 PP |
1408 | |
1409 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1410 | ||
1411 | /* Reduce security in favour of increased compatibility, if the admin | |
1412 | decides to make that trade-off. */ | |
1413 | if (gnutls_compat_mode) | |
83da1223 | 1414 | { |
17c76198 PP |
1415 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1416 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1417 | gnutls_session_enable_compatibility_mode(state->session); | |
1418 | #else | |
1419 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1420 | #endif | |
83da1223 PH |
1421 | } |
1422 | ||
17c76198 | 1423 | *caller_state = state; |
17c76198 | 1424 | return OK; |
83da1223 PH |
1425 | } |
1426 | ||
1427 | ||
1428 | ||
059ec3d9 | 1429 | /************************************************* |
17c76198 | 1430 | * Extract peer information * |
059ec3d9 PH |
1431 | *************************************************/ |
1432 | ||
17c76198 | 1433 | /* Called from both server and client code. |
4fe99a6c PP |
1434 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1435 | and we use that to detect double-calls. | |
059ec3d9 | 1436 | |
75fe387d PP |
1437 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1438 | for logging in the server side, but for the client side, we log after teardown | |
1439 | in src/deliver.c. While the session is up, we can twist about states and | |
1440 | repoint tls_* globals, but those variables used for logging or other variable | |
1441 | expansion that happens _after_ delivery need to have a longer life-time. | |
1442 | ||
1443 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1444 | doing this more than once per generation of a state context. We set them in | |
1445 | the state context, and repoint tls_* to them. After the state goes away, the | |
1446 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1447 | ||
1448 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1449 | don't apply. | |
1450 | ||
059ec3d9 | 1451 | Arguments: |
17c76198 | 1452 | state exim_gnutls_state_st * |
cf0c6164 | 1453 | errstr pointer to error string |
059ec3d9 | 1454 | |
17c76198 | 1455 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1456 | */ |
1457 | ||
17c76198 | 1458 | static int |
cf0c6164 | 1459 | peer_status(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 1460 | { |
75fe387d | 1461 | uschar cipherbuf[256]; |
27f19eb4 | 1462 | const gnutls_datum_t *cert_list; |
75fe387d | 1463 | int old_pool, rc; |
17c76198 | 1464 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1465 | gnutls_protocol_t protocol; |
1466 | gnutls_cipher_algorithm_t cipher; | |
1467 | gnutls_kx_algorithm_t kx; | |
1468 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1469 | gnutls_certificate_type_t ct; |
1470 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1471 | uschar *p, *dn_buf; |
17c76198 | 1472 | size_t sz; |
059ec3d9 | 1473 | |
4fe99a6c | 1474 | if (state->have_set_peerdn) |
17c76198 | 1475 | return OK; |
4fe99a6c | 1476 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1477 | |
4fe99a6c | 1478 | state->peerdn = NULL; |
059ec3d9 | 1479 | |
4fe99a6c PP |
1480 | /* tls_cipher */ |
1481 | cipher = gnutls_cipher_get(state->session); | |
1482 | protocol = gnutls_protocol_get_version(state->session); | |
1483 | mac = gnutls_mac_get(state->session); | |
1484 | kx = gnutls_kx_get(state->session); | |
1485 | ||
75fe387d | 1486 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1487 | "%s:%s:%d", |
1488 | gnutls_protocol_get_name(protocol), | |
1489 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1490 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1491 | ||
1492 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1493 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1494 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1495 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1496 | if (isspace(*p)) |
1497 | *p = '-'; | |
75fe387d PP |
1498 | old_pool = store_pool; |
1499 | store_pool = POOL_PERM; | |
1500 | state->ciphersuite = string_copy(cipherbuf); | |
1501 | store_pool = old_pool; | |
817d9f57 | 1502 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1503 | |
1504 | /* tls_peerdn */ | |
17c76198 | 1505 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1506 | |
17c76198 PP |
1507 | if (cert_list == NULL || cert_list_size == 0) |
1508 | { | |
17c76198 PP |
1509 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1510 | cert_list, cert_list_size); | |
e51c7be2 | 1511 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1512 | return tls_error(US"certificate verification failed", |
cf0c6164 | 1513 | "no certificate received from peer", state->host, errstr); |
17c76198 PP |
1514 | return OK; |
1515 | } | |
059ec3d9 | 1516 | |
17c76198 PP |
1517 | ct = gnutls_certificate_type_get(state->session); |
1518 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1519 | { |
17c76198 | 1520 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1521 | DEBUG(D_tls) |
1522 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1523 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1524 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1525 | ctn, state->host, errstr); |
17c76198 | 1526 | return OK; |
83da1223 | 1527 | } |
059ec3d9 | 1528 | |
e51c7be2 JH |
1529 | #define exim_gnutls_peer_err(Label) \ |
1530 | do { \ | |
1531 | if (rc != GNUTLS_E_SUCCESS) \ | |
1532 | { \ | |
1533 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1534 | (Label), gnutls_strerror(rc)); \ | |
1535 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
cf0c6164 | 1536 | return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ |
e51c7be2 JH |
1537 | return OK; \ |
1538 | } \ | |
1539 | } while (0) | |
17c76198 | 1540 | |
9d1c15ef JH |
1541 | rc = import_cert(&cert_list[0], &crt); |
1542 | exim_gnutls_peer_err(US"cert 0"); | |
1543 | ||
1544 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1545 | |
17c76198 PP |
1546 | sz = 0; |
1547 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1548 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1549 | { |
17c76198 PP |
1550 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1551 | return FAIL; /* should not happen */ | |
059ec3d9 | 1552 | } |
17c76198 PP |
1553 | dn_buf = store_get_perm(sz); |
1554 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1555 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1556 | |
17c76198 PP |
1557 | state->peerdn = dn_buf; |
1558 | ||
1559 | return OK; | |
1560 | #undef exim_gnutls_peer_err | |
1561 | } | |
059ec3d9 | 1562 | |
059ec3d9 | 1563 | |
059ec3d9 | 1564 | |
059ec3d9 | 1565 | |
17c76198 PP |
1566 | /************************************************* |
1567 | * Verify peer certificate * | |
1568 | *************************************************/ | |
059ec3d9 | 1569 | |
17c76198 PP |
1570 | /* Called from both server and client code. |
1571 | *Should* be using a callback registered with | |
1572 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1573 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1574 | |
17c76198 | 1575 | Arguments: |
899b8bbc JH |
1576 | state exim_gnutls_state_st * |
1577 | errstr where to put an error message | |
059ec3d9 | 1578 | |
17c76198 PP |
1579 | Returns: |
1580 | FALSE if the session should be rejected | |
1581 | TRUE if the cert is okay or we just don't care | |
1582 | */ | |
059ec3d9 | 1583 | |
17c76198 | 1584 | static BOOL |
28646fa9 | 1585 | verify_certificate(exim_gnutls_state_st * state, uschar ** errstr) |
17c76198 PP |
1586 | { |
1587 | int rc; | |
899b8bbc JH |
1588 | uint verify; |
1589 | ||
1590 | if (state->verify_requirement == VERIFY_NONE) | |
1591 | return TRUE; | |
17c76198 | 1592 | |
cf0c6164 | 1593 | *errstr = NULL; |
17c76198 | 1594 | |
cf0c6164 | 1595 | if ((rc = peer_status(state, errstr)) != OK) |
e6060e2c | 1596 | { |
17c76198 | 1597 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1598 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1599 | } |
1600 | else | |
899b8bbc JH |
1601 | |
1602 | { | |
1603 | #ifdef SUPPORT_DANE | |
1604 | if (state->verify_requirement == VERIFY_DANE && state->host) | |
1605 | { | |
1606 | /* Using dane_verify_session_crt() would be easy, as it does it all for us | |
1607 | including talking to a DNS resolver. But we want to do that bit ourselves | |
1608 | as the testsuite intercepts and fakes its own DNS environment. */ | |
1609 | ||
1610 | dane_state_t s; | |
1611 | dane_query_t r; | |
899b8bbc | 1612 | uint lsize; |
94c13285 JH |
1613 | const gnutls_datum_t * certlist = |
1614 | gnutls_certificate_get_peers(state->session, &lsize); | |
1615 | int usage = tls_out.tlsa_usage; | |
1616 | ||
1617 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION | |
1618 | /* Split the TLSA records into two sets, TA and EE selectors. Run the | |
1619 | dane-verification separately so that we know which selector verified; | |
1620 | then we know whether to do CA-chain-verification and name-verification | |
1621 | (needed for TA but not EE). */ | |
1622 | ||
1623 | if (usage == ((1<<DANESSL_USAGE_DANE_TA) | (1<<DANESSL_USAGE_DANE_EE))) | |
bd5b3f3c | 1624 | { /* a mixed-usage bundle */ |
94c13285 JH |
1625 | int i, j, nrec; |
1626 | const char ** dd; | |
1627 | int * ddl; | |
1628 | ||
1629 | for(nrec = 0; state->dane_data_len[nrec]; ) nrec++; | |
1630 | nrec++; | |
1631 | ||
1632 | dd = store_get(nrec * sizeof(uschar *)); | |
1633 | ddl = store_get(nrec * sizeof(int)); | |
1634 | nrec--; | |
1635 | ||
1636 | if ((rc = dane_state_init(&s, 0))) | |
1637 | goto tlsa_prob; | |
1638 | ||
1639 | for (usage = DANESSL_USAGE_DANE_EE; | |
1640 | usage >= DANESSL_USAGE_DANE_TA; usage--) | |
1641 | { /* take records with this usage */ | |
1642 | for (j = i = 0; i < nrec; i++) | |
1643 | if (state->dane_data[i][0] == usage) | |
1644 | { | |
1645 | dd[j] = state->dane_data[i]; | |
1646 | ddl[j++] = state->dane_data_len[i]; | |
1647 | } | |
1648 | if (j) | |
1649 | { | |
1650 | dd[j] = NULL; | |
1651 | ddl[j] = 0; | |
1652 | ||
1653 | if ((rc = dane_raw_tlsa(s, &r, (char * const *)dd, ddl, 1, 0))) | |
1654 | goto tlsa_prob; | |
1655 | ||
1656 | if ((rc = dane_verify_crt_raw(s, certlist, lsize, | |
1657 | gnutls_certificate_type_get(state->session), | |
1658 | r, 0, | |
1659 | usage == DANESSL_USAGE_DANE_EE | |
1660 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1661 | &verify))) | |
1662 | { | |
1663 | DEBUG(D_tls) | |
1664 | debug_printf("TLSA record problem: %s\n", dane_strerror(rc)); | |
1665 | } | |
1666 | else if (verify == 0) /* verification passed */ | |
1667 | { | |
1668 | usage = 1 << usage; | |
1669 | break; | |
1670 | } | |
1671 | } | |
1672 | } | |
899b8bbc | 1673 | |
94c13285 JH |
1674 | if (rc) goto tlsa_prob; |
1675 | } | |
1676 | else | |
1677 | # endif | |
899b8bbc | 1678 | { |
94c13285 JH |
1679 | if ( (rc = dane_state_init(&s, 0)) |
1680 | || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len, | |
1681 | 1, 0)) | |
1682 | || (rc = dane_verify_crt_raw(s, certlist, lsize, | |
1683 | gnutls_certificate_type_get(state->session), | |
5ec37a55 | 1684 | r, 0, |
94c13285 JH |
1685 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1686 | usage == (1 << DANESSL_USAGE_DANE_EE) | |
1687 | ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, | |
1688 | # else | |
1689 | 0, | |
1690 | # endif | |
1691 | &verify)) | |
1692 | ) | |
1693 | goto tlsa_prob; | |
899b8bbc | 1694 | } |
94c13285 JH |
1695 | |
1696 | if (verify != 0) /* verification failed */ | |
899b8bbc JH |
1697 | { |
1698 | gnutls_datum_t str; | |
1699 | (void) dane_verification_status_print(verify, &str, 0); | |
1700 | *errstr = US str.data; /* don't bother to free */ | |
1701 | goto badcert; | |
1702 | } | |
1703 | state->peer_dane_verified = TRUE; | |
28646fa9 | 1704 | |
94c13285 JH |
1705 | # ifdef GNUTLS_BROKEN_DANE_VALIDATION |
1706 | /* If a TA-mode TLSA record was used for verification we must additionally | |
1707 | verify the CA chain and the cert name. For EE-mode, skip it. */ | |
28646fa9 | 1708 | |
94c13285 JH |
1709 | if (usage & (1 << DANESSL_USAGE_DANE_EE)) |
1710 | # endif | |
28646fa9 JH |
1711 | { |
1712 | state->peer_cert_verified = TRUE; | |
1713 | goto goodcert; | |
1714 | } | |
899b8bbc JH |
1715 | } |
1716 | #endif | |
1717 | ||
17c76198 | 1718 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
899b8bbc | 1719 | } |
e6060e2c | 1720 | |
899b8bbc | 1721 | /* Handle the result of verification. INVALID is set if any others are. */ |
059ec3d9 | 1722 | |
28646fa9 | 1723 | if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) |
17c76198 PP |
1724 | { |
1725 | state->peer_cert_verified = FALSE; | |
cf0c6164 JH |
1726 | if (!*errstr) |
1727 | *errstr = verify & GNUTLS_CERT_REVOKED | |
1728 | ? US"certificate revoked" : US"certificate invalid"; | |
059ec3d9 | 1729 | |
17c76198 | 1730 | DEBUG(D_tls) |
e51c7be2 | 1731 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1732 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1733 | |
e51c7be2 | 1734 | if (state->verify_requirement >= VERIFY_REQUIRED) |
899b8bbc | 1735 | goto badcert; |
17c76198 | 1736 | DEBUG(D_tls) |
4789da3a | 1737 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1738 | } |
e51c7be2 | 1739 | |
17c76198 PP |
1740 | else |
1741 | { | |
aa2a70ba | 1742 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1743 | { |
1744 | int sep = 0; | |
55414b25 | 1745 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 | 1746 | uschar * name; |
76075bb5 | 1747 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) |
e51c7be2 JH |
1748 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) |
1749 | break; | |
1750 | if (!name) | |
1751 | { | |
1752 | DEBUG(D_tls) | |
1753 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba | 1754 | if (state->verify_requirement >= VERIFY_REQUIRED) |
899b8bbc | 1755 | goto badcert; |
aa2a70ba | 1756 | return TRUE; |
e51c7be2 JH |
1757 | } |
1758 | } | |
17c76198 | 1759 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1760 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1761 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1762 | } |
059ec3d9 | 1763 | |
28646fa9 JH |
1764 | goodcert: |
1765 | state->tlsp->peerdn = state->peerdn; | |
1766 | return TRUE; | |
899b8bbc | 1767 | |
b83314e3 | 1768 | #ifdef SUPPORT_DANE |
94c13285 JH |
1769 | tlsa_prob: |
1770 | *errstr = string_sprintf("TLSA record problem: %s", dane_strerror(rc)); | |
b83314e3 JH |
1771 | #endif |
1772 | ||
899b8bbc JH |
1773 | badcert: |
1774 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1775 | return FALSE; | |
17c76198 | 1776 | } |
059ec3d9 | 1777 | |
17c76198 PP |
1778 | |
1779 | ||
1780 | ||
1781 | /* ------------------------------------------------------------------------ */ | |
1782 | /* Callbacks */ | |
1783 | ||
1784 | /* Logging function which can be registered with | |
1785 | * gnutls_global_set_log_function() | |
1786 | * gnutls_global_set_log_level() 0..9 | |
1787 | */ | |
af3498d6 | 1788 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1789 | static void |
17c76198 | 1790 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1791 | { |
8c79eebf PP |
1792 | size_t len = strlen(message); |
1793 | if (len < 1) | |
1794 | { | |
1795 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1796 | return; | |
1797 | } | |
1798 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1799 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1800 | } |
af3498d6 | 1801 | #endif |
059ec3d9 | 1802 | |
059ec3d9 | 1803 | |
17c76198 PP |
1804 | /* Called after client hello, should handle SNI work. |
1805 | This will always set tls_sni (state->received_sni) if available, | |
1806 | and may trigger presenting different certificates, | |
1807 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1808 | |
17c76198 PP |
1809 | Should be registered with |
1810 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1811 | |
17c76198 PP |
1812 | "This callback must return 0 on success or a gnutls error code to terminate the |
1813 | handshake.". | |
059ec3d9 | 1814 | |
17c76198 PP |
1815 | For inability to get SNI information, we return 0. |
1816 | We only return non-zero if re-setup failed. | |
817d9f57 | 1817 | Only used for server-side TLS. |
17c76198 | 1818 | */ |
44bbabb5 | 1819 | |
17c76198 PP |
1820 | static int |
1821 | exim_sni_handling_cb(gnutls_session_t session) | |
1822 | { | |
1823 | char sni_name[MAX_HOST_LEN]; | |
1824 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1825 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1826 | unsigned int sni_type; |
1827 | int rc, old_pool; | |
cf0c6164 | 1828 | uschar * dummy_errstr; |
17c76198 PP |
1829 | |
1830 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1831 | if (rc != GNUTLS_E_SUCCESS) |
1832 | { | |
1833 | DEBUG(D_tls) { | |
1834 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1835 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1836 | else | |
1837 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1838 | gnutls_strerror(rc), rc); | |
cf0c6164 | 1839 | } |
b34fc30c PP |
1840 | return 0; |
1841 | } | |
1842 | ||
17c76198 PP |
1843 | if (sni_type != GNUTLS_NAME_DNS) |
1844 | { | |
1845 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1846 | return 0; | |
1847 | } | |
44bbabb5 | 1848 | |
17c76198 PP |
1849 | /* We now have a UTF-8 string in sni_name */ |
1850 | old_pool = store_pool; | |
1851 | store_pool = POOL_PERM; | |
1852 | state->received_sni = string_copyn(US sni_name, data_len); | |
1853 | store_pool = old_pool; | |
1854 | ||
1855 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1856 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1857 | |
1858 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1859 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1860 | ||
1861 | if (!state->trigger_sni_changes) | |
1862 | return 0; | |
1863 | ||
cf0c6164 | 1864 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
1865 | { |
1866 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1867 | been offered. The best we can do now is abort. */ | |
1868 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1869 | } | |
1870 | ||
cf0c6164 | 1871 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
1872 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
1873 | ||
1874 | return 0; | |
059ec3d9 PH |
1875 | } |
1876 | ||
1877 | ||
1878 | ||
f2de3a33 | 1879 | #ifndef DISABLE_OCSP |
44662487 JH |
1880 | |
1881 | static int | |
1882 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1883 | gnutls_datum_t * ocsp_response) | |
1884 | { | |
1885 | int ret; | |
47195144 | 1886 | DEBUG(D_tls) debug_printf("OCSP stapling callback: %s\n", US ptr); |
44662487 | 1887 | |
44662487 JH |
1888 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1889 | { | |
1890 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
5903c6ff | 1891 | CS ptr); |
018058b2 | 1892 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1893 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1894 | } | |
1895 | ||
018058b2 | 1896 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1897 | return 0; |
1898 | } | |
1899 | ||
1900 | #endif | |
1901 | ||
1902 | ||
0cbf2b82 | 1903 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1904 | /* |
1905 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1906 | for an exim TLS connection (either direction), raising a tls:cert event |
1907 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1908 | can deny verification. |
1909 | ||
1910 | Return 0 for the handshake to continue or non-zero to terminate. | |
1911 | */ | |
1912 | ||
1913 | static int | |
723fe533 | 1914 | verify_cb(gnutls_session_t session) |
a7538db1 | 1915 | { |
27f19eb4 | 1916 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1917 | unsigned int cert_list_size = 0; |
1918 | gnutls_x509_crt_t crt; | |
1919 | int rc; | |
b30275b8 | 1920 | uschar * yield; |
a7538db1 JH |
1921 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1922 | ||
bd5b3f3c | 1923 | if ((cert_list = gnutls_certificate_get_peers(session, &cert_list_size))) |
a7538db1 JH |
1924 | while (cert_list_size--) |
1925 | { | |
bd5b3f3c | 1926 | if ((rc = import_cert(&cert_list[cert_list_size], &crt)) != GNUTLS_E_SUCCESS) |
a7538db1 JH |
1927 | { |
1928 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1929 | cert_list_size, gnutls_strerror(rc)); | |
1930 | break; | |
1931 | } | |
1932 | ||
1933 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1934 | if ((yield = event_raise(state->event_action, |
1935 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1936 | { |
1937 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1938 | "SSL verify denied by event-action: depth=%d: %s", |
1939 | cert_list_size, yield); | |
a7538db1 JH |
1940 | return 1; /* reject */ |
1941 | } | |
1942 | state->tlsp->peercert = NULL; | |
1943 | } | |
1944 | ||
1945 | return 0; | |
1946 | } | |
1947 | ||
1948 | #endif | |
44662487 JH |
1949 | |
1950 | ||
17c76198 PP |
1951 | |
1952 | /* ------------------------------------------------------------------------ */ | |
1953 | /* Exported functions */ | |
1954 | ||
1955 | ||
1956 | ||
1957 | ||
059ec3d9 PH |
1958 | /************************************************* |
1959 | * Start a TLS session in a server * | |
1960 | *************************************************/ | |
1961 | ||
1962 | /* This is called when Exim is running as a server, after having received | |
1963 | the STARTTLS command. It must respond to that command, and then negotiate | |
1964 | a TLS session. | |
1965 | ||
1966 | Arguments: | |
83da1223 | 1967 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 1968 | errstr pointer to error string |
059ec3d9 PH |
1969 | |
1970 | Returns: OK on success | |
1971 | DEFER for errors before the start of the negotiation | |
4c04137d | 1972 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
1973 | continue running. |
1974 | */ | |
1975 | ||
1976 | int | |
cf0c6164 | 1977 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
1978 | { |
1979 | int rc; | |
cf0c6164 | 1980 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
1981 | |
1982 | /* Check for previous activation */ | |
817d9f57 | 1983 | if (tls_in.active >= 0) |
059ec3d9 | 1984 | { |
cf0c6164 | 1985 | tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); |
925ac8e4 | 1986 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
1987 | return FAIL; |
1988 | } | |
1989 | ||
1990 | /* Initialize the library. If it fails, it will already have logged the error | |
1991 | and sent an SMTP response. */ | |
1992 | ||
17c76198 | 1993 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1994 | |
cf0c6164 | 1995 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 1996 | NULL, tls_verify_certificates, tls_crl, |
cf0c6164 | 1997 | require_ciphers, &state, errstr)) != OK) return rc; |
059ec3d9 | 1998 | |
059ec3d9 PH |
1999 | /* If this is a host for which certificate verification is mandatory or |
2000 | optional, set up appropriately. */ | |
2001 | ||
059ec3d9 | 2002 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 2003 | { |
e51c7be2 JH |
2004 | DEBUG(D_tls) |
2005 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
2006 | state->verify_requirement = VERIFY_REQUIRED; |
2007 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
2008 | } | |
059ec3d9 | 2009 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 2010 | { |
e51c7be2 JH |
2011 | DEBUG(D_tls) |
2012 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
2013 | state->verify_requirement = VERIFY_OPTIONAL; |
2014 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
2015 | } | |
2016 | else | |
2017 | { | |
e51c7be2 JH |
2018 | DEBUG(D_tls) |
2019 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
2020 | state->verify_requirement = VERIFY_NONE; |
2021 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
2022 | } | |
059ec3d9 | 2023 | |
0cbf2b82 | 2024 | #ifndef DISABLE_EVENT |
723fe533 JH |
2025 | if (event_action) |
2026 | { | |
2027 | state->event_action = event_action; | |
2028 | gnutls_session_set_ptr(state->session, state); | |
2029 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
2030 | } | |
2031 | #endif | |
2032 | ||
17c76198 PP |
2033 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
2034 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 2035 | |
17c76198 PP |
2036 | gnutls_handshake_set_post_client_hello_function(state->session, |
2037 | exim_sni_handling_cb); | |
059ec3d9 PH |
2038 | |
2039 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
2040 | on connection, where outputting anything now upsets the clients and tends to | |
2041 | make them disconnect. We need to have an explicit fflush() here, to force out | |
2042 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
2043 | mode, the fflush() happens when smtp_getc() is called. */ | |
2044 | ||
817d9f57 | 2045 | if (!state->tlsp->on_connect) |
059ec3d9 | 2046 | { |
925ac8e4 | 2047 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 2048 | fflush(smtp_out); |
059ec3d9 PH |
2049 | } |
2050 | ||
2051 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
2052 | that the GnuTLS library doesn't. */ | |
2053 | ||
17c76198 | 2054 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
2055 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
2056 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
2057 | state->fd_in = fileno(smtp_in); |
2058 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
2059 | |
2060 | sigalrm_seen = FALSE; | |
2061 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 2062 | do |
17c76198 | 2063 | rc = gnutls_handshake(state->session); |
157a7880 | 2064 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
2065 | alarm(0); |
2066 | ||
17c76198 | 2067 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 2068 | { |
059ec3d9 PH |
2069 | /* It seems that, except in the case of a timeout, we have to close the |
2070 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
2071 | until the server times out. */ | |
2072 | ||
60d10ce7 | 2073 | if (sigalrm_seen) |
ad7fc6eb | 2074 | { |
cf0c6164 | 2075 | tls_error(US"gnutls_handshake", "timed out", NULL, errstr); |
ad7fc6eb JH |
2076 | gnutls_db_remove_session(state->session); |
2077 | } | |
60d10ce7 | 2078 | else |
059ec3d9 | 2079 | { |
cf0c6164 | 2080 | tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); |
f5d25c2b | 2081 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 2082 | gnutls_deinit(state->session); |
ed62aae3 | 2083 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 2084 | millisleep(500); |
ad7fc6eb | 2085 | shutdown(state->fd_out, SHUT_WR); |
60d10ce7 | 2086 | for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ |
f1e894f3 PH |
2087 | (void)fclose(smtp_out); |
2088 | (void)fclose(smtp_in); | |
60d10ce7 | 2089 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
2090 | } |
2091 | ||
2092 | return FAIL; | |
2093 | } | |
2094 | ||
2095 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
2096 | ||
17c76198 PP |
2097 | /* Verify after the fact */ |
2098 | ||
899b8bbc | 2099 | if (!verify_certificate(state, errstr)) |
059ec3d9 | 2100 | { |
9d1c15ef | 2101 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 2102 | { |
cf0c6164 | 2103 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 2104 | return FAIL; |
17c76198 | 2105 | } |
9d1c15ef JH |
2106 | DEBUG(D_tls) |
2107 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 2108 | *errstr); |
059ec3d9 PH |
2109 | } |
2110 | ||
17c76198 PP |
2111 | /* Figure out peer DN, and if authenticated, etc. */ |
2112 | ||
cf0c6164 | 2113 | if ((rc = peer_status(state, NULL)) != OK) return rc; |
17c76198 PP |
2114 | |
2115 | /* Sets various Exim expansion variables; always safe within server */ | |
2116 | ||
9d1c15ef | 2117 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
2118 | |
2119 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
2120 | and initialize appropriately. */ | |
2121 | ||
17c76198 | 2122 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
2123 | |
2124 | receive_getc = tls_getc; | |
0d81dabc | 2125 | receive_getbuf = tls_getbuf; |
584e96c6 | 2126 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
2127 | receive_ungetc = tls_ungetc; |
2128 | receive_feof = tls_feof; | |
2129 | receive_ferror = tls_ferror; | |
58eb016e | 2130 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 2131 | |
059ec3d9 PH |
2132 | return OK; |
2133 | } | |
2134 | ||
2135 | ||
2136 | ||
2137 | ||
aa2a70ba JH |
2138 | static void |
2139 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
2140 | smtp_transport_options_block * ob) | |
2141 | { | |
5130845b | 2142 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 2143 | { |
4af0d74a | 2144 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 2145 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2146 | string_domain_utf8_to_alabel(host->name, NULL); |
2147 | #else | |
2148 | host->name; | |
2149 | #endif | |
aa2a70ba JH |
2150 | DEBUG(D_tls) |
2151 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
2152 | state->exp_tls_verify_cert_hostnames); | |
2153 | } | |
2154 | } | |
aa2a70ba JH |
2155 | |
2156 | ||
899b8bbc JH |
2157 | |
2158 | ||
2159 | #ifdef SUPPORT_DANE | |
2160 | /* Given our list of RRs from the TLSA lookup, build a lookup block in | |
2161 | GnuTLS-DANE's preferred format. Hang it on the state str for later | |
2162 | use in DANE verification. | |
2163 | ||
2164 | We point at the dnsa data not copy it, so it must remain valid until | |
2165 | after verification is done.*/ | |
2166 | ||
3674140c | 2167 | static BOOL |
899b8bbc JH |
2168 | dane_tlsa_load(exim_gnutls_state_st * state, dns_answer * dnsa) |
2169 | { | |
2170 | dns_record * rr; | |
2171 | dns_scan dnss; | |
2172 | int i; | |
2173 | const char ** dane_data; | |
2174 | int * dane_data_len; | |
2175 | ||
2176 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS), i = 1; | |
2177 | rr; | |
2178 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
2179 | ) if (rr->type == T_TLSA) i++; | |
2180 | ||
2181 | dane_data = store_get(i * sizeof(uschar *)); | |
2182 | dane_data_len = store_get(i * sizeof(int)); | |
2183 | ||
2184 | for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS), i = 0; | |
2185 | rr; | |
2186 | rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) | |
2187 | ) if (rr->type == T_TLSA) | |
2188 | { | |
2189 | const uschar * p = rr->data; | |
3674140c JH |
2190 | uint8_t usage = p[0], sel = p[1], type = p[2]; |
2191 | ||
2192 | DEBUG(D_tls) | |
2193 | debug_printf("TLSA: %d %d %d size %d\n", usage, sel, type, rr->size); | |
2194 | ||
94c13285 JH |
2195 | if ( (usage != DANESSL_USAGE_DANE_TA && usage != DANESSL_USAGE_DANE_EE) |
2196 | || (sel != 0 && sel != 1) | |
2197 | ) | |
2198 | continue; | |
3674140c JH |
2199 | switch(type) |
2200 | { | |
2201 | case 0: /* Full: cannot check at present */ | |
2202 | break; | |
2203 | case 1: if (rr->size != 3 + 256/8) continue; /* sha2-256 */ | |
2204 | break; | |
2205 | case 2: if (rr->size != 3 + 512/8) continue; /* sha2-512 */ | |
2206 | break; | |
2207 | default: continue; | |
2208 | } | |
899b8bbc JH |
2209 | |
2210 | tls_out.tlsa_usage |= 1<<usage; | |
2211 | dane_data[i] = p; | |
2212 | dane_data_len[i++] = rr->size; | |
2213 | } | |
3674140c JH |
2214 | |
2215 | if (!i) return FALSE; | |
2216 | ||
899b8bbc JH |
2217 | dane_data[i] = NULL; |
2218 | dane_data_len[i] = 0; | |
2219 | ||
2220 | state->dane_data = (char * const *)dane_data; | |
2221 | state->dane_data_len = dane_data_len; | |
3674140c | 2222 | return TRUE; |
899b8bbc JH |
2223 | } |
2224 | #endif | |
2225 | ||
2226 | ||
2227 | ||
059ec3d9 PH |
2228 | /************************************************* |
2229 | * Start a TLS session in a client * | |
2230 | *************************************************/ | |
2231 | ||
2232 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2233 | ||
2234 | Arguments: | |
2235 | fd the fd of the connection | |
2236 | host connected host (for messages) | |
83da1223 | 2237 | addr the first address (not used) |
a7538db1 | 2238 | tb transport (always smtp) |
899b8bbc JH |
2239 | tlsa_dnsa non-NULL, either request or require dane for this host, and |
2240 | a TLSA record found. Therefore, dane verify required. | |
2241 | Which implies cert must be requested and supplied, dane | |
2242 | verify must pass, and cert verify irrelevant (incl. | |
2243 | hostnames), and (caller handled) require_tls | |
cf0c6164 JH |
2244 | errstr error string pointer |
2245 | ||
059ec3d9 PH |
2246 | Returns: OK/DEFER/FAIL (because using common functions), |
2247 | but for a client, DEFER and FAIL have the same meaning | |
2248 | */ | |
2249 | ||
2250 | int | |
17c76198 | 2251 | tls_client_start(int fd, host_item *host, |
f5d78688 | 2252 | address_item *addr ARG_UNUSED, |
cf0c6164 | 2253 | transport_instance * tb, |
c0635b6d | 2254 | #ifdef SUPPORT_DANE |
899b8bbc | 2255 | dns_answer * tlsa_dnsa, |
0e66b3b6 | 2256 | #endif |
cf0c6164 | 2257 | uschar ** errstr) |
059ec3d9 | 2258 | { |
a7538db1 JH |
2259 | smtp_transport_options_block *ob = |
2260 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 2261 | int rc; |
899b8bbc | 2262 | exim_gnutls_state_st * state = NULL; |
5ec37a55 | 2263 | uschar *cipher_list = NULL; |
f2de3a33 | 2264 | #ifndef DISABLE_OCSP |
5130845b JH |
2265 | BOOL require_ocsp = |
2266 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 2267 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 2268 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 2269 | #endif |
059ec3d9 | 2270 | |
17c76198 | 2271 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 2272 | |
5ec37a55 | 2273 | #ifdef SUPPORT_DANE |
cf260049 | 2274 | if (tlsa_dnsa && ob->dane_require_tls_ciphers) |
5ec37a55 PP |
2275 | { |
2276 | /* not using expand_check_tlsvar because not yet in state */ | |
2277 | if (!expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", | |
2278 | &cipher_list, errstr)) | |
2279 | return DEFER; | |
cf260049 JH |
2280 | cipher_list = cipher_list && *cipher_list |
2281 | ? ob->dane_require_tls_ciphers : ob->tls_require_ciphers; | |
5ec37a55 PP |
2282 | } |
2283 | #endif | |
2284 | ||
2285 | if (!cipher_list) | |
2286 | cipher_list = ob->tls_require_ciphers; | |
2287 | ||
65867078 JH |
2288 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
2289 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
5ec37a55 | 2290 | cipher_list, &state, errstr)) != OK) |
2b4a568d | 2291 | return rc; |
059ec3d9 | 2292 | |
54c90be1 | 2293 | { |
65867078 JH |
2294 | int dh_min_bits = ob->tls_dh_min_bits; |
2295 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2296 | { | |
2297 | DEBUG(D_tls) | |
2298 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2299 | " clamping %d up to %d\n", | |
2300 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2301 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2302 | } | |
54c90be1 | 2303 | |
65867078 JH |
2304 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2305 | " acceptable bits to %d\n", | |
2306 | dh_min_bits); | |
2307 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2308 | } | |
83da1223 | 2309 | |
94431adb | 2310 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2311 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2312 | the specified host patterns if one of them is defined */ | |
2313 | ||
899b8bbc | 2314 | #ifdef SUPPORT_DANE |
3674140c | 2315 | if (tlsa_dnsa && dane_tlsa_load(state, tlsa_dnsa)) |
899b8bbc JH |
2316 | { |
2317 | DEBUG(D_tls) | |
2318 | debug_printf("TLS: server certificate DANE required.\n"); | |
2319 | state->verify_requirement = VERIFY_DANE; | |
2320 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
899b8bbc JH |
2321 | } |
2322 | else | |
2323 | #endif | |
2324 | if ( ( state->exp_tls_verify_certificates | |
2325 | && !ob->tls_verify_hosts | |
2326 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) | |
2327 | ) | |
2328 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK | |
2329 | ) | |
17c76198 | 2330 | { |
aa2a70ba | 2331 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2332 | DEBUG(D_tls) |
2333 | debug_printf("TLS: server certificate verification required.\n"); | |
2334 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2335 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2336 | } | |
5130845b | 2337 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2338 | { |
aa2a70ba | 2339 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2340 | DEBUG(D_tls) |
2341 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2342 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2343 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2344 | } | |
2345 | else | |
2346 | { | |
e51c7be2 JH |
2347 | DEBUG(D_tls) |
2348 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2349 | state->verify_requirement = VERIFY_NONE; |
2350 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2351 | } |
059ec3d9 | 2352 | |
f2de3a33 JH |
2353 | #ifndef DISABLE_OCSP |
2354 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2355 | if (request_ocsp) |
9d1c15ef JH |
2356 | { |
2357 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2358 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2359 | NULL, 0, NULL)) != OK) | |
9d1c15ef | 2360 | return tls_error(US"cert-status-req", |
cf0c6164 | 2361 | gnutls_strerror(rc), state->host, errstr); |
44662487 | 2362 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2363 | } |
2b4a568d JH |
2364 | #endif |
2365 | ||
0cbf2b82 | 2366 | #ifndef DISABLE_EVENT |
774ef2d7 | 2367 | if (tb->event_action) |
a7538db1 | 2368 | { |
774ef2d7 | 2369 | state->event_action = tb->event_action; |
a7538db1 | 2370 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2371 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2372 | } |
2373 | #endif | |
2374 | ||
27f19eb4 | 2375 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2376 | state->fd_in = fd; |
2377 | state->fd_out = fd; | |
059ec3d9 | 2378 | |
9d1c15ef | 2379 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2380 | /* There doesn't seem to be a built-in timeout on connection. */ |
2381 | ||
2382 | sigalrm_seen = FALSE; | |
65867078 | 2383 | alarm(ob->command_timeout); |
17c76198 | 2384 | do |
17c76198 | 2385 | rc = gnutls_handshake(state->session); |
f1fed05b | 2386 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
2387 | alarm(0); |
2388 | ||
4fe99a6c | 2389 | if (rc != GNUTLS_E_SUCCESS) |
60d10ce7 JH |
2390 | if (sigalrm_seen) |
2391 | { | |
2392 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
cf0c6164 | 2393 | return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); |
60d10ce7 JH |
2394 | } |
2395 | else | |
cf0c6164 | 2396 | return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); |
4fe99a6c | 2397 | |
17c76198 | 2398 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2399 | |
17c76198 | 2400 | /* Verify late */ |
059ec3d9 | 2401 | |
899b8bbc | 2402 | if (!verify_certificate(state, errstr)) |
cf0c6164 | 2403 | return tls_error(US"certificate verification failed", *errstr, state->host, errstr); |
059ec3d9 | 2404 | |
f2de3a33 | 2405 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2406 | if (require_ocsp) |
2407 | { | |
2408 | DEBUG(D_tls) | |
2409 | { | |
2410 | gnutls_datum_t stapling; | |
2411 | gnutls_ocsp_resp_t resp; | |
2412 | gnutls_datum_t printed; | |
2413 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2414 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2415 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2416 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2417 | ) | |
2418 | { | |
65867078 | 2419 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2420 | gnutls_free(printed.data); |
2421 | } | |
2422 | else | |
cf0c6164 | 2423 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host, errstr); |
2b4a568d JH |
2424 | } |
2425 | ||
2b4a568d | 2426 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2427 | { |
2428 | tls_out.ocsp = OCSP_FAILED; | |
cf0c6164 | 2429 | return tls_error(US"certificate status check failed", NULL, state->host, errstr); |
018058b2 | 2430 | } |
2b4a568d | 2431 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2432 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2433 | } |
2434 | #endif | |
2435 | ||
17c76198 | 2436 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2437 | |
cf0c6164 | 2438 | if ((rc = peer_status(state, errstr)) != OK) |
2b4a568d | 2439 | return rc; |
059ec3d9 | 2440 | |
4fe99a6c | 2441 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2442 | |
9d1c15ef | 2443 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2444 | |
059ec3d9 PH |
2445 | return OK; |
2446 | } | |
2447 | ||
2448 | ||
2449 | ||
17c76198 | 2450 | |
059ec3d9 | 2451 | /************************************************* |
17c76198 | 2452 | * Close down a TLS session * |
059ec3d9 PH |
2453 | *************************************************/ |
2454 | ||
17c76198 PP |
2455 | /* This is also called from within a delivery subprocess forked from the |
2456 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2457 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2458 | |
dec766a1 WB |
2459 | Arguments: |
2460 | shutdown 1 if TLS close-alert is to be sent, | |
2461 | 2 if also response to be waited for | |
2462 | ||
17c76198 | 2463 | Returns: nothing |
059ec3d9 PH |
2464 | */ |
2465 | ||
17c76198 | 2466 | void |
dec766a1 | 2467 | tls_close(BOOL is_server, int shutdown) |
059ec3d9 | 2468 | { |
817d9f57 | 2469 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2470 | |
389ca47a | 2471 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2472 | |
2473 | if (shutdown) | |
2474 | { | |
dec766a1 WB |
2475 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", |
2476 | shutdown > 1 ? " (with response-wait)" : ""); | |
2477 | ||
2478 | alarm(2); | |
2479 | gnutls_bye(state->session, shutdown > 1 ? GNUTLS_SHUT_RDWR : GNUTLS_SHUT_WR); | |
2480 | alarm(0); | |
17c76198 PP |
2481 | } |
2482 | ||
2483 | gnutls_deinit(state->session); | |
ed62aae3 HSHR |
2484 | gnutls_certificate_free_credentials(state->x509_cred); |
2485 | ||
17c76198 | 2486 | |
389ca47a | 2487 | state->tlsp->active = -1; |
b808677c | 2488 | if (state->xfer_buffer) store_free(state->xfer_buffer); |
17c76198 PP |
2489 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2490 | ||
b808677c | 2491 | if (!state_server.session && !state_client.session) |
17c76198 PP |
2492 | { |
2493 | gnutls_global_deinit(); | |
2494 | exim_gnutls_base_init_done = FALSE; | |
2495 | } | |
059ec3d9 PH |
2496 | } |
2497 | ||
2498 | ||
2499 | ||
17c76198 | 2500 | |
0d81dabc JH |
2501 | static BOOL |
2502 | tls_refill(unsigned lim) | |
2503 | { | |
2504 | exim_gnutls_state_st * state = &state_server; | |
2505 | ssize_t inbytes; | |
2506 | ||
2507 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2508 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2509 | ||
f1fed05b | 2510 | sigalrm_seen = FALSE; |
0d81dabc JH |
2511 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); |
2512 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2513 | MIN(ssl_xfer_buffer_size, lim)); | |
9723f966 JH |
2514 | if (smtp_receive_timeout > 0) alarm(0); |
2515 | ||
2516 | if (had_command_timeout) /* set by signal handler */ | |
2517 | smtp_command_timeout_exit(); /* does not return */ | |
2518 | if (had_command_sigterm) | |
2519 | smtp_command_sigterm_exit(); | |
2520 | if (had_data_timeout) | |
2521 | smtp_data_timeout_exit(); | |
2522 | if (had_data_sigint) | |
2523 | smtp_data_sigint_exit(); | |
2524 | ||
2525 | /* Timeouts do not get this far. A zero-byte return appears to mean that the | |
2526 | TLS session has been closed down, not that the socket itself has been closed | |
2527 | down. Revert to non-TLS handling. */ | |
0d81dabc JH |
2528 | |
2529 | if (sigalrm_seen) | |
2530 | { | |
2531 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
8b77d27a | 2532 | state->xfer_error = TRUE; |
0d81dabc JH |
2533 | return FALSE; |
2534 | } | |
2535 | ||
2536 | else if (inbytes == 0) | |
2537 | { | |
2538 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2539 | ||
2540 | receive_getc = smtp_getc; | |
2541 | receive_getbuf = smtp_getbuf; | |
2542 | receive_get_cache = smtp_get_cache; | |
2543 | receive_ungetc = smtp_ungetc; | |
2544 | receive_feof = smtp_feof; | |
2545 | receive_ferror = smtp_ferror; | |
2546 | receive_smtp_buffered = smtp_buffered; | |
2547 | ||
2548 | gnutls_deinit(state->session); | |
2549 | gnutls_certificate_free_credentials(state->x509_cred); | |
2550 | ||
2551 | state->session = NULL; | |
2552 | state->tlsp->active = -1; | |
2553 | state->tlsp->bits = 0; | |
2554 | state->tlsp->certificate_verified = FALSE; | |
2555 | tls_channelbinding_b64 = NULL; | |
2556 | state->tlsp->cipher = NULL; | |
2557 | state->tlsp->peercert = NULL; | |
2558 | state->tlsp->peerdn = NULL; | |
2559 | ||
2560 | return FALSE; | |
2561 | } | |
2562 | ||
2563 | /* Handle genuine errors */ | |
2564 | ||
2565 | else if (inbytes < 0) | |
2566 | { | |
2567 | record_io_error(state, (int) inbytes, US"recv", NULL); | |
8b77d27a | 2568 | state->xfer_error = TRUE; |
0d81dabc JH |
2569 | return FALSE; |
2570 | } | |
2571 | #ifndef DISABLE_DKIM | |
2572 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
2573 | #endif | |
2574 | state->xfer_buffer_hwm = (int) inbytes; | |
2575 | state->xfer_buffer_lwm = 0; | |
2576 | return TRUE; | |
2577 | } | |
2578 | ||
059ec3d9 PH |
2579 | /************************************************* |
2580 | * TLS version of getc * | |
2581 | *************************************************/ | |
2582 | ||
2583 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2584 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2585 | Only used by the server-side TLS. |
059ec3d9 | 2586 | |
17c76198 PP |
2587 | This feeds DKIM and should be used for all message-body reads. |
2588 | ||
bd8fbe36 | 2589 | Arguments: lim Maximum amount to read/bufffer |
059ec3d9 PH |
2590 | Returns: the next character or EOF |
2591 | */ | |
2592 | ||
2593 | int | |
bd8fbe36 | 2594 | tls_getc(unsigned lim) |
059ec3d9 | 2595 | { |
0d81dabc | 2596 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 2597 | |
0d81dabc JH |
2598 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2599 | if (!tls_refill(lim)) | |
2600 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 2601 | |
0d81dabc | 2602 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2603 | |
0d81dabc JH |
2604 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
2605 | } | |
059ec3d9 | 2606 | |
0d81dabc JH |
2607 | uschar * |
2608 | tls_getbuf(unsigned * len) | |
2609 | { | |
2610 | exim_gnutls_state_st * state = &state_server; | |
2611 | unsigned size; | |
2612 | uschar * buf; | |
059ec3d9 | 2613 | |
0d81dabc JH |
2614 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2615 | if (!tls_refill(*len)) | |
059ec3d9 | 2616 | { |
0d81dabc JH |
2617 | if (!state->xfer_error) return smtp_getbuf(len); |
2618 | *len = 0; | |
2619 | return NULL; | |
059ec3d9 | 2620 | } |
059ec3d9 | 2621 | |
0d81dabc JH |
2622 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
2623 | size = *len; | |
2624 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
2625 | state->xfer_buffer_lwm += size; | |
2626 | *len = size; | |
2627 | return buf; | |
059ec3d9 PH |
2628 | } |
2629 | ||
0d81dabc | 2630 | |
584e96c6 JH |
2631 | void |
2632 | tls_get_cache() | |
2633 | { | |
9960d1e5 | 2634 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2635 | exim_gnutls_state_st * state = &state_server; |
2636 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2637 | if (n > 0) | |
2638 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2639 | #endif |
9960d1e5 | 2640 | } |
584e96c6 | 2641 | |
059ec3d9 | 2642 | |
925ac8e4 JH |
2643 | BOOL |
2644 | tls_could_read(void) | |
2645 | { | |
2646 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
2647 | || gnutls_record_check_pending(state_server.session) > 0; | |
2648 | } | |
2649 | ||
2650 | ||
059ec3d9 | 2651 | |
17c76198 | 2652 | |
059ec3d9 PH |
2653 | /************************************************* |
2654 | * Read bytes from TLS channel * | |
2655 | *************************************************/ | |
2656 | ||
17c76198 PP |
2657 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2658 | then the caller must feed DKIM. | |
817d9f57 | 2659 | |
059ec3d9 PH |
2660 | Arguments: |
2661 | buff buffer of data | |
2662 | len size of buffer | |
2663 | ||
2664 | Returns: the number of bytes read | |
2665 | -1 after a failed read | |
2666 | */ | |
2667 | ||
2668 | int | |
817d9f57 | 2669 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2670 | { |
817d9f57 | 2671 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2672 | ssize_t inbytes; |
059ec3d9 | 2673 | |
17c76198 PP |
2674 | if (len > INT_MAX) |
2675 | len = INT_MAX; | |
059ec3d9 | 2676 | |
17c76198 PP |
2677 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2678 | DEBUG(D_tls) | |
2679 | debug_printf("*** PROBABLY A BUG *** " \ | |
2680 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2681 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2682 | ||
2683 | DEBUG(D_tls) | |
2684 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2685 | state->session, buff, len); | |
2686 | ||
2687 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2688 | if (inbytes > 0) return inbytes; |
2689 | if (inbytes == 0) | |
2690 | { | |
2691 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2692 | } | |
17c76198 | 2693 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2694 | |
2695 | return -1; | |
2696 | } | |
2697 | ||
2698 | ||
2699 | ||
17c76198 | 2700 | |
059ec3d9 PH |
2701 | /************************************************* |
2702 | * Write bytes down TLS channel * | |
2703 | *************************************************/ | |
2704 | ||
2705 | /* | |
2706 | Arguments: | |
817d9f57 | 2707 | is_server channel specifier |
059ec3d9 PH |
2708 | buff buffer of data |
2709 | len number of bytes | |
925ac8e4 | 2710 | more more data expected soon |
059ec3d9 PH |
2711 | |
2712 | Returns: the number of bytes after a successful write, | |
2713 | -1 after a failed write | |
2714 | */ | |
2715 | ||
2716 | int | |
925ac8e4 | 2717 | tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2718 | { |
17c76198 PP |
2719 | ssize_t outbytes; |
2720 | size_t left = len; | |
817d9f57 | 2721 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
925ac8e4 JH |
2722 | #ifdef SUPPORT_CORK |
2723 | static BOOL corked = FALSE; | |
2724 | ||
2725 | if (more && !corked) gnutls_record_cork(state->session); | |
2726 | #endif | |
2727 | ||
2728 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
2729 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 2730 | |
059ec3d9 PH |
2731 | while (left > 0) |
2732 | { | |
17c76198 PP |
2733 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2734 | buff, left); | |
2735 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2736 | |
17c76198 | 2737 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2738 | if (outbytes < 0) |
2739 | { | |
17c76198 | 2740 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2741 | return -1; |
2742 | } | |
2743 | if (outbytes == 0) | |
2744 | { | |
17c76198 | 2745 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2746 | return -1; |
2747 | } | |
2748 | ||
2749 | left -= outbytes; | |
2750 | buff += outbytes; | |
2751 | } | |
2752 | ||
17c76198 PP |
2753 | if (len > INT_MAX) |
2754 | { | |
2755 | DEBUG(D_tls) | |
2756 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2757 | len); | |
2758 | len = INT_MAX; | |
2759 | } | |
2760 | ||
925ac8e4 JH |
2761 | #ifdef SUPPORT_CORK |
2762 | if (more != corked) | |
2763 | { | |
2764 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
2765 | corked = more; | |
2766 | } | |
2767 | #endif | |
2768 | ||
17c76198 | 2769 | return (int) len; |
059ec3d9 PH |
2770 | } |
2771 | ||
2772 | ||
2773 | ||
17c76198 | 2774 | |
059ec3d9 | 2775 | /************************************************* |
17c76198 | 2776 | * Random number generation * |
059ec3d9 PH |
2777 | *************************************************/ |
2778 | ||
17c76198 PP |
2779 | /* Pseudo-random number generation. The result is not expected to be |
2780 | cryptographically strong but not so weak that someone will shoot themselves | |
2781 | in the foot using it as a nonce in input in some email header scheme or | |
2782 | whatever weirdness they'll twist this into. The result should handle fork() | |
2783 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2784 | |
17c76198 PP |
2785 | Arguments: |
2786 | max range maximum | |
2787 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2788 | */ |
2789 | ||
af3498d6 | 2790 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2791 | int |
2792 | vaguely_random_number(int max) | |
059ec3d9 | 2793 | { |
17c76198 PP |
2794 | unsigned int r; |
2795 | int i, needed_len; | |
2796 | uschar *p; | |
2797 | uschar smallbuf[sizeof(r)]; | |
2798 | ||
2799 | if (max <= 1) | |
2800 | return 0; | |
2801 | ||
2802 | needed_len = sizeof(r); | |
2803 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2804 | * asked for a number less than 10. */ | |
2805 | for (r = max, i = 0; r; ++i) | |
2806 | r >>= 1; | |
2807 | i = (i + 7) / 8; | |
2808 | if (i < needed_len) | |
2809 | needed_len = i; | |
2810 | ||
2811 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2812 | if (i < 0) | |
059ec3d9 | 2813 | { |
17c76198 PP |
2814 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2815 | return vaguely_random_number_fallback(max); | |
2816 | } | |
2817 | r = 0; | |
2818 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2819 | { | |
2820 | r *= 256; | |
2821 | r += *p; | |
059ec3d9 PH |
2822 | } |
2823 | ||
17c76198 PP |
2824 | /* We don't particularly care about weighted results; if someone wants |
2825 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2826 | return r % max; | |
059ec3d9 | 2827 | } |
af3498d6 PP |
2828 | #else /* HAVE_GNUTLS_RND */ |
2829 | int | |
2830 | vaguely_random_number(int max) | |
2831 | { | |
2832 | return vaguely_random_number_fallback(max); | |
2833 | } | |
2834 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2835 | |
36f12725 NM |
2836 | |
2837 | ||
2838 | ||
3375e053 PP |
2839 | /************************************************* |
2840 | * Let tls_require_ciphers be checked at startup * | |
2841 | *************************************************/ | |
2842 | ||
2843 | /* The tls_require_ciphers option, if set, must be something which the | |
2844 | library can parse. | |
2845 | ||
2846 | Returns: NULL on success, or error message | |
2847 | */ | |
2848 | ||
2849 | uschar * | |
2850 | tls_validate_require_cipher(void) | |
2851 | { | |
2852 | int rc; | |
2853 | uschar *expciphers = NULL; | |
2854 | gnutls_priority_t priority_cache; | |
2855 | const char *errpos; | |
cf0c6164 | 2856 | uschar * dummy_errstr; |
3375e053 PP |
2857 | |
2858 | #define validate_check_rc(Label) do { \ | |
2859 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2860 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2861 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2862 | ||
2863 | if (exim_gnutls_base_init_done) | |
2864 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2865 | "already initialised GnuTLS, Exim developer bug"); | |
2866 | ||
a5f239e4 | 2867 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2868 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2869 | { |
2870 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2871 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2872 | } | |
2873 | #endif | |
3375e053 PP |
2874 | rc = gnutls_global_init(); |
2875 | validate_check_rc(US"gnutls_global_init()"); | |
2876 | exim_gnutls_base_init_done = TRUE; | |
2877 | ||
2878 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2879 | return_deinit(NULL); | |
2880 | ||
cf0c6164 JH |
2881 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
2882 | &dummy_errstr)) | |
3375e053 PP |
2883 | return_deinit(US"failed to expand tls_require_ciphers"); |
2884 | ||
2885 | if (!(expciphers && *expciphers)) | |
2886 | return_deinit(NULL); | |
2887 | ||
2888 | DEBUG(D_tls) | |
2889 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2890 | ||
2891 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2892 | validate_check_rc(string_sprintf( | |
2893 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2894 | expciphers, errpos - CS expciphers, errpos)); | |
2895 | ||
2896 | #undef return_deinit | |
2897 | #undef validate_check_rc | |
2898 | gnutls_global_deinit(); | |
2899 | ||
2900 | return NULL; | |
2901 | } | |
2902 | ||
2903 | ||
2904 | ||
2905 | ||
36f12725 NM |
2906 | /************************************************* |
2907 | * Report the library versions. * | |
2908 | *************************************************/ | |
2909 | ||
2910 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2911 | ||
2912 | Arguments: a FILE* to print the results to | |
2913 | Returns: nothing | |
2914 | */ | |
2915 | ||
2916 | void | |
2917 | tls_version_report(FILE *f) | |
2918 | { | |
754a0503 PP |
2919 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2920 | " Runtime: %s\n", | |
2921 | LIBGNUTLS_VERSION, | |
2922 | gnutls_check_version(NULL)); | |
36f12725 NM |
2923 | } |
2924 | ||
2b4a568d JH |
2925 | /* vi: aw ai sw=2 |
2926 | */ | |
059ec3d9 | 2927 | /* End of tls-gnu.c */ |