Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
9242a7e8 | 5 | /* Copyright (c) University of Cambridge 1995 - 2017 */ |
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 | |
7e07527a | 66 | |
f2de3a33 | 67 | #ifndef DISABLE_OCSP |
2b4a568d JH |
68 | # include <gnutls/ocsp.h> |
69 | #endif | |
059ec3d9 | 70 | |
17c76198 | 71 | /* GnuTLS 2 vs 3 |
059ec3d9 | 72 | |
17c76198 PP |
73 | GnuTLS 3 only: |
74 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 75 | |
17c76198 PP |
76 | Changes: |
77 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
78 | */ | |
059ec3d9 | 79 | |
17c76198 | 80 | /* Local static variables for GnuTLS */ |
059ec3d9 | 81 | |
17c76198 | 82 | /* Values for verify_requirement */ |
059ec3d9 | 83 | |
e51c7be2 | 84 | enum peer_verify_requirement |
aa2a70ba | 85 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 86 | |
17c76198 PP |
87 | /* This holds most state for server or client; with this, we can set up an |
88 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
89 | over the TLS variables available for expansion. | |
059ec3d9 | 90 | |
17c76198 PP |
91 | Some of these correspond to variables in globals.c; those variables will |
92 | be set to point to content in one of these instances, as appropriate for | |
93 | the stage of the process lifetime. | |
059ec3d9 | 94 | |
389ca47a | 95 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 96 | */ |
059ec3d9 | 97 | |
17c76198 | 98 | typedef struct exim_gnutls_state { |
9d1c15ef | 99 | gnutls_session_t session; |
17c76198 | 100 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 101 | gnutls_priority_t priority_cache; |
17c76198 | 102 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
103 | int fd_in; |
104 | int fd_out; | |
105 | BOOL peer_cert_verified; | |
106 | BOOL trigger_sni_changes; | |
107 | BOOL have_set_peerdn; | |
17c76198 | 108 | const struct host_item *host; |
9d1c15ef JH |
109 | gnutls_x509_crt_t peercert; |
110 | uschar *peerdn; | |
111 | uschar *ciphersuite; | |
112 | uschar *received_sni; | |
17c76198 PP |
113 | |
114 | const uschar *tls_certificate; | |
115 | const uschar *tls_privatekey; | |
116 | const uschar *tls_sni; /* client send only, not received */ | |
117 | const uschar *tls_verify_certificates; | |
118 | const uschar *tls_crl; | |
119 | const uschar *tls_require_ciphers; | |
e51c7be2 | 120 | |
17c76198 PP |
121 | uschar *exp_tls_certificate; |
122 | uschar *exp_tls_privatekey; | |
17c76198 PP |
123 | uschar *exp_tls_verify_certificates; |
124 | uschar *exp_tls_crl; | |
125 | uschar *exp_tls_require_ciphers; | |
44662487 | 126 | uschar *exp_tls_ocsp_file; |
55414b25 | 127 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 128 | #ifndef DISABLE_EVENT |
a7538db1 JH |
129 | uschar *event_action; |
130 | #endif | |
17c76198 | 131 | |
389ca47a | 132 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 133 | |
17c76198 PP |
134 | uschar *xfer_buffer; |
135 | int xfer_buffer_lwm; | |
136 | int xfer_buffer_hwm; | |
137 | int xfer_eof; | |
138 | int xfer_error; | |
17c76198 PP |
139 | } exim_gnutls_state_st; |
140 | ||
141 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
f2ed27cf JH |
142 | .session = NULL, |
143 | .x509_cred = NULL, | |
144 | .priority_cache = NULL, | |
145 | .verify_requirement = VERIFY_NONE, | |
146 | .fd_in = -1, | |
147 | .fd_out = -1, | |
148 | .peer_cert_verified = FALSE, | |
149 | .trigger_sni_changes =FALSE, | |
150 | .have_set_peerdn = FALSE, | |
151 | .host = NULL, | |
152 | .peercert = NULL, | |
153 | .peerdn = NULL, | |
154 | .ciphersuite = NULL, | |
155 | .received_sni = NULL, | |
156 | ||
157 | .tls_certificate = NULL, | |
158 | .tls_privatekey = NULL, | |
159 | .tls_sni = NULL, | |
160 | .tls_verify_certificates = NULL, | |
161 | .tls_crl = NULL, | |
162 | .tls_require_ciphers =NULL, | |
163 | ||
164 | .exp_tls_certificate = NULL, | |
165 | .exp_tls_privatekey = NULL, | |
166 | .exp_tls_verify_certificates = NULL, | |
167 | .exp_tls_crl = NULL, | |
168 | .exp_tls_require_ciphers = NULL, | |
169 | .exp_tls_ocsp_file = NULL, | |
170 | .exp_tls_verify_cert_hostnames = NULL, | |
0cbf2b82 | 171 | #ifndef DISABLE_EVENT |
f2ed27cf | 172 | .event_action = NULL, |
e51c7be2 | 173 | #endif |
f2ed27cf JH |
174 | .tlsp = NULL, |
175 | ||
176 | .xfer_buffer = NULL, | |
177 | .xfer_buffer_lwm = 0, | |
178 | .xfer_buffer_hwm = 0, | |
179 | .xfer_eof = 0, | |
180 | .xfer_error = 0, | |
17c76198 | 181 | }; |
83da1223 | 182 | |
17c76198 PP |
183 | /* Not only do we have our own APIs which don't pass around state, assuming |
184 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
185 | for callbacks, or as part of the session, so we have to keep a "this is the | |
186 | context we're currently dealing with" pointer and rely upon being | |
187 | single-threaded to keep from processing data on an inbound TLS connection while | |
188 | talking to another TLS connection for an outbound check. This does mean that | |
189 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
190 | second connection. |
191 | XXX But see gnutls_session_get_ptr() | |
192 | */ | |
059ec3d9 | 193 | |
17c76198 | 194 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 195 | |
17c76198 PP |
196 | /* dh_params are initialised once within the lifetime of a process using TLS; |
197 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
198 | don't want to repeat this. */ | |
83da1223 | 199 | |
17c76198 | 200 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 201 | |
17c76198 | 202 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 203 | |
17c76198 | 204 | static const int ssl_session_timeout = 200; |
059ec3d9 | 205 | |
17c76198 | 206 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 207 | |
17c76198 | 208 | /* Guard library core initialisation */ |
83da1223 | 209 | |
17c76198 | 210 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 211 | |
4fb7df6d | 212 | #ifndef DISABLE_OCSP |
9196d5bf | 213 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 214 | #endif |
9196d5bf | 215 | |
059ec3d9 | 216 | |
17c76198 PP |
217 | /* ------------------------------------------------------------------------ */ |
218 | /* macros */ | |
83da1223 | 219 | |
17c76198 | 220 | #define MAX_HOST_LEN 255 |
83da1223 | 221 | |
17c76198 PP |
222 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
223 | the library logging; a value less than 0 disables the calls to set up logging | |
ef9da2ee JH |
224 | callbacks. Possibly GNuTLS also looks for an environment variable |
225 | "GNUTLS_DEBUG_LEVEL". */ | |
2c17bb02 | 226 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 227 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 228 | #endif |
83da1223 | 229 | |
2c17bb02 | 230 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 231 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 232 | #endif |
83da1223 | 233 | |
af3498d6 PP |
234 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
235 | can ask for a bit-strength. Without that, we stick to the constant we had | |
236 | before, for now. */ | |
2c17bb02 | 237 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 238 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 239 | #endif |
af3498d6 | 240 | |
17c76198 | 241 | #define exim_gnutls_err_check(Label) do { \ |
cf0c6164 JH |
242 | if (rc != GNUTLS_E_SUCCESS) \ |
243 | return tls_error((Label), gnutls_strerror(rc), host, errstr); \ | |
244 | } while (0) | |
059ec3d9 | 245 | |
cf0c6164 JH |
246 | #define expand_check_tlsvar(Varname, errstr) \ |
247 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 248 | |
17c76198 | 249 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
250 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
251 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
252 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
253 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
254 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
255 | * isn't available sometimes, so this needs to become a conditional | |
256 | * compilation; the sanest way to deal with this being a problem on | |
257 | * older OSes is to block it in the Local/Makefile with this compiler | |
258 | * definition */ | |
e51c7be2 JH |
259 | # ifndef AVOID_GNUTLS_PKCS11 |
260 | # define HAVE_GNUTLS_PKCS11 | |
261 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 262 | #endif |
83da1223 | 263 | |
af3498d6 PP |
264 | |
265 | ||
266 | ||
267 | /* ------------------------------------------------------------------------ */ | |
268 | /* Callback declarations */ | |
269 | ||
270 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
271 | static void exim_gnutls_logger_cb(int level, const char *message); | |
272 | #endif | |
273 | ||
274 | static int exim_sni_handling_cb(gnutls_session_t session); | |
275 | ||
f2de3a33 | 276 | #ifndef DISABLE_OCSP |
44662487 JH |
277 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
278 | gnutls_datum_t * ocsp_response); | |
279 | #endif | |
af3498d6 PP |
280 | |
281 | ||
282 | ||
17c76198 PP |
283 | /* ------------------------------------------------------------------------ */ |
284 | /* Static functions */ | |
059ec3d9 PH |
285 | |
286 | /************************************************* | |
287 | * Handle TLS error * | |
288 | *************************************************/ | |
289 | ||
290 | /* Called from lots of places when errors occur before actually starting to do | |
291 | the TLS handshake, that is, while the session is still in clear. Always returns | |
292 | DEFER for a server and FAIL for a client so that most calls can use "return | |
293 | tls_error(...)" to do this processing and then give an appropriate return. A | |
294 | single function is used for both server and client, because it is called from | |
295 | some shared functions. | |
296 | ||
297 | Argument: | |
298 | prefix text to include in the logged error | |
7199e1ee TF |
299 | msg additional error string (may be NULL) |
300 | usually obtained from gnutls_strerror() | |
17c76198 PP |
301 | host NULL if setting up a server; |
302 | the connected host if setting up a client | |
cf0c6164 | 303 | errstr pointer to returned error string |
059ec3d9 PH |
304 | |
305 | Returns: OK/DEFER/FAIL | |
306 | */ | |
307 | ||
308 | static int | |
cf0c6164 JH |
309 | tls_error(const uschar *prefix, const char *msg, const host_item *host, |
310 | uschar ** errstr) | |
059ec3d9 | 311 | { |
cf0c6164 JH |
312 | if (errstr) |
313 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); | |
314 | return host ? FAIL : DEFER; | |
059ec3d9 PH |
315 | } |
316 | ||
317 | ||
318 | ||
17c76198 | 319 | |
059ec3d9 | 320 | /************************************************* |
17c76198 | 321 | * Deal with logging errors during I/O * |
059ec3d9 PH |
322 | *************************************************/ |
323 | ||
17c76198 | 324 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 325 | |
17c76198 PP |
326 | Argument: |
327 | state the current GnuTLS exim state container | |
328 | rc the GnuTLS error code, or 0 if it's a local error | |
329 | when text identifying read or write | |
330 | text local error text when ec is 0 | |
059ec3d9 | 331 | |
17c76198 | 332 | Returns: nothing |
059ec3d9 PH |
333 | */ |
334 | ||
17c76198 PP |
335 | static void |
336 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 337 | { |
cf0c6164 JH |
338 | const char * msg; |
339 | uschar * errstr; | |
059ec3d9 | 340 | |
17c76198 PP |
341 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
342 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
343 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
344 | else | |
345 | msg = gnutls_strerror(rc); | |
059ec3d9 | 346 | |
cf0c6164 JH |
347 | (void) tls_error(when, msg, state->host, &errstr); |
348 | ||
349 | if (state->host) | |
350 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
351 | state->host->name, state->host->address, errstr); | |
352 | else | |
353 | { | |
354 | uschar * conn_info = smtp_get_connection_info(); | |
355 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
356 | /* I'd like to get separated H= here, but too hard for now */ | |
357 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
358 | } | |
17c76198 | 359 | } |
059ec3d9 | 360 | |
059ec3d9 | 361 | |
059ec3d9 | 362 | |
059ec3d9 | 363 | |
17c76198 PP |
364 | /************************************************* |
365 | * Set various Exim expansion vars * | |
366 | *************************************************/ | |
059ec3d9 | 367 | |
e51c7be2 JH |
368 | #define exim_gnutls_cert_err(Label) \ |
369 | do \ | |
370 | { \ | |
371 | if (rc != GNUTLS_E_SUCCESS) \ | |
372 | { \ | |
373 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
374 | (Label), gnutls_strerror(rc)); \ | |
375 | return rc; \ | |
376 | } \ | |
377 | } while (0) | |
9d1c15ef JH |
378 | |
379 | static int | |
27f19eb4 | 380 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
381 | { |
382 | int rc; | |
383 | ||
384 | rc = gnutls_x509_crt_init(crtp); | |
385 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
386 | ||
387 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
388 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
389 | ||
390 | return rc; | |
391 | } | |
392 | ||
393 | #undef exim_gnutls_cert_err | |
394 | ||
395 | ||
17c76198 PP |
396 | /* We set various Exim global variables from the state, once a session has |
397 | been established. With TLS callouts, may need to change this to stack | |
398 | variables, or just re-call it with the server state after client callout | |
399 | has finished. | |
059ec3d9 | 400 | |
9d1c15ef | 401 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
402 | |
403 | Sets: | |
404 | tls_active fd | |
405 | tls_bits strength indicator | |
406 | tls_certificate_verified bool indicator | |
407 | tls_channelbinding_b64 for some SASL mechanisms | |
408 | tls_cipher a string | |
9d1c15ef | 409 | tls_peercert pointer to library internal |
17c76198 PP |
410 | tls_peerdn a string |
411 | tls_sni a (UTF-8) string | |
9d1c15ef | 412 | tls_ourcert pointer to library internal |
17c76198 PP |
413 | |
414 | Argument: | |
415 | state the relevant exim_gnutls_state_st * | |
416 | */ | |
417 | ||
418 | static void | |
9d1c15ef | 419 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 420 | { |
17c76198 | 421 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
422 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
423 | int old_pool; | |
424 | int rc; | |
425 | gnutls_datum_t channel; | |
426 | #endif | |
9d1c15ef | 427 | tls_support * tlsp = state->tlsp; |
17c76198 | 428 | |
9d1c15ef | 429 | tlsp->active = state->fd_out; |
17c76198 PP |
430 | |
431 | cipher = gnutls_cipher_get(state->session); | |
432 | /* returns size in "bytes" */ | |
9d1c15ef | 433 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 434 | |
9d1c15ef | 435 | tlsp->cipher = state->ciphersuite; |
17c76198 | 436 | |
817d9f57 | 437 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 438 | |
9d1c15ef | 439 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 440 | |
17c76198 PP |
441 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
442 | only available for use for authenticators while this TLS session is running. */ | |
443 | ||
444 | tls_channelbinding_b64 = NULL; | |
445 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
446 | channel.data = NULL; | |
447 | channel.size = 0; | |
448 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
449 | if (rc) { | |
450 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
451 | } else { | |
452 | old_pool = store_pool; | |
453 | store_pool = POOL_PERM; | |
f4d091fb | 454 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
455 | store_pool = old_pool; |
456 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
457 | } | |
458 | #endif | |
459 | ||
9d1c15ef JH |
460 | /* peercert is set in peer_status() */ |
461 | tlsp->peerdn = state->peerdn; | |
462 | tlsp->sni = state->received_sni; | |
463 | ||
464 | /* record our certificate */ | |
465 | { | |
27f19eb4 | 466 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
467 | gnutls_x509_crt_t crt; |
468 | ||
469 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
470 | } | |
059ec3d9 PH |
471 | } |
472 | ||
473 | ||
474 | ||
17c76198 | 475 | |
059ec3d9 | 476 | /************************************************* |
575643cd | 477 | * Setup up DH parameters * |
059ec3d9 PH |
478 | *************************************************/ |
479 | ||
575643cd | 480 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
481 | be re-generated every so often, depending on security policy. What we do is to |
482 | keep these parameters in a file in the spool directory. If the file does not | |
483 | exist, we generate them. This means that it is easy to cause a regeneration. | |
484 | ||
485 | The new file is written as a temporary file and renamed, so that an incomplete | |
486 | file is never present. If two processes both compute some new parameters, you | |
487 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
488 | prevent this. | |
489 | ||
059ec3d9 PH |
490 | Returns: OK/DEFER/FAIL |
491 | */ | |
492 | ||
493 | static int | |
cf0c6164 | 494 | init_server_dh(uschar ** errstr) |
059ec3d9 | 495 | { |
17c76198 PP |
496 | int fd, rc; |
497 | unsigned int dh_bits; | |
27f19eb4 | 498 | gnutls_datum_t m; |
a799883d PP |
499 | uschar filename_buf[PATH_MAX]; |
500 | uschar *filename = NULL; | |
17c76198 | 501 | size_t sz; |
a799883d PP |
502 | uschar *exp_tls_dhparam; |
503 | BOOL use_file_in_spool = FALSE; | |
504 | BOOL use_fixed_file = FALSE; | |
17c76198 | 505 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 506 | |
17c76198 | 507 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 508 | |
17c76198 PP |
509 | rc = gnutls_dh_params_init(&dh_server_params); |
510 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 511 | |
a799883d PP |
512 | m.data = NULL; |
513 | m.size = 0; | |
514 | ||
cf0c6164 | 515 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
516 | return DEFER; |
517 | ||
518 | if (!exp_tls_dhparam) | |
519 | { | |
520 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
521 | m.data = US std_dh_prime_default(); | |
522 | m.size = Ustrlen(m.data); | |
523 | } | |
524 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
525 | use_file_in_spool = TRUE; | |
526 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
527 | { | |
528 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
529 | return OK; | |
530 | } | |
531 | else if (exp_tls_dhparam[0] != '/') | |
532 | { | |
f5d25c2b | 533 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
cf0c6164 | 534 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); |
a799883d PP |
535 | m.size = Ustrlen(m.data); |
536 | } | |
537 | else | |
538 | { | |
539 | use_fixed_file = TRUE; | |
540 | filename = exp_tls_dhparam; | |
541 | } | |
542 | ||
543 | if (m.data) | |
544 | { | |
545 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
546 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
547 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
548 | return OK; | |
549 | } | |
550 | ||
af3498d6 PP |
551 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
552 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
553 | different filename and ensure we have sufficient bits. */ |
554 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
555 | if (!dh_bits) | |
cf0c6164 | 556 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 557 | DEBUG(D_tls) |
b34fc30c | 558 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
559 | dh_bits); |
560 | #else | |
561 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
562 | DEBUG(D_tls) | |
563 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
564 | dh_bits); | |
565 | #endif | |
059ec3d9 | 566 | |
3375e053 PP |
567 | /* Some clients have hard-coded limits. */ |
568 | if (dh_bits > tls_dh_max_bits) | |
569 | { | |
570 | DEBUG(D_tls) | |
571 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
572 | tls_dh_max_bits); | |
573 | dh_bits = tls_dh_max_bits; | |
574 | } | |
575 | ||
a799883d PP |
576 | if (use_file_in_spool) |
577 | { | |
578 | if (!string_format(filename_buf, sizeof(filename_buf), | |
579 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 580 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
581 | filename = filename_buf; |
582 | } | |
059ec3d9 | 583 | |
b5aea5e1 | 584 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 585 | parameters. */ |
059ec3d9 | 586 | |
f5d25c2b | 587 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 588 | { |
b5aea5e1 | 589 | struct stat statbuf; |
17c76198 PP |
590 | FILE *fp; |
591 | int saved_errno; | |
592 | ||
593 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
594 | { | |
595 | saved_errno = errno; | |
596 | (void)close(fd); | |
cf0c6164 | 597 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
598 | } |
599 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
600 | { |
601 | (void)close(fd); | |
cf0c6164 | 602 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 603 | } |
40c90bca | 604 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
605 | { |
606 | saved_errno = errno; | |
607 | (void)close(fd); | |
608 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
cf0c6164 | 609 | strerror(saved_errno), NULL, errstr); |
b5aea5e1 | 610 | } |
059ec3d9 | 611 | |
b5aea5e1 | 612 | m.size = statbuf.st_size; |
40c90bca | 613 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
614 | { |
615 | fclose(fp); | |
cf0c6164 | 616 | return tls_error(US"malloc failed", strerror(errno), NULL, errstr); |
17c76198 | 617 | } |
40c90bca | 618 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
619 | { |
620 | saved_errno = errno; | |
621 | fclose(fp); | |
622 | free(m.data); | |
cf0c6164 | 623 | return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
624 | } |
625 | fclose(fp); | |
b5aea5e1 | 626 | |
17c76198 | 627 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 628 | free(m.data); |
17c76198 PP |
629 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
630 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
631 | } |
632 | ||
633 | /* If the file does not exist, fall through to compute new data and cache it. | |
634 | If there was any other opening error, it is serious. */ | |
635 | ||
182ad5cf PH |
636 | else if (errno == ENOENT) |
637 | { | |
17c76198 | 638 | rc = -1; |
182ad5cf | 639 | DEBUG(D_tls) |
17c76198 | 640 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
641 | } |
642 | else | |
17c76198 | 643 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 644 | NULL, NULL, errstr); |
b5aea5e1 PH |
645 | |
646 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
647 | is not useful. One particular case of this is when upgrading from an older | |
648 | release of Exim in which the data was stored in a different format. We don't | |
649 | try to be clever and support both formats; we just regenerate new data in this | |
650 | case. */ | |
651 | ||
17c76198 | 652 | if (rc < 0) |
b5aea5e1 | 653 | { |
17c76198 | 654 | uschar *temp_fn; |
201f5254 | 655 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 656 | |
17c76198 PP |
657 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
658 | return tls_error(US"Filename too long to generate replacement", | |
cf0c6164 | 659 | CS filename, NULL, errstr); |
059ec3d9 | 660 | |
17c76198 | 661 | temp_fn = string_copy(US "%s.XXXXXXX"); |
f5d25c2b | 662 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
cf0c6164 | 663 | return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); |
059ec3d9 PH |
664 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
665 | ||
201f5254 PP |
666 | /* GnuTLS overshoots! |
667 | * If we ask for 2236, we might get 2237 or more. | |
668 | * But there's no way to ask GnuTLS how many bits there really are. | |
669 | * We can ask how many bits were used in a TLS session, but that's it! | |
670 | * The prime itself is hidden behind too much abstraction. | |
671 | * So we ask for less, and proceed on a wing and a prayer. | |
672 | * First attempt, subtracted 3 for 2233 and got 2240. | |
673 | */ | |
cae6e576 | 674 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
675 | { |
676 | dh_bits_gen = dh_bits - 10; | |
677 | DEBUG(D_tls) | |
678 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
679 | dh_bits_gen); | |
680 | } | |
681 | ||
682 | DEBUG(D_tls) | |
683 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
684 | dh_bits_gen); | |
685 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
686 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
687 | ||
688 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
689 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
690 | sample apps handle this. */ | |
691 | ||
692 | sz = 0; | |
693 | m.data = NULL; | |
694 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
695 | m.data, &sz); | |
696 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
697 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
698 | m.size = sz; | |
40c90bca | 699 | if (!(m.data = malloc(m.size))) |
cf0c6164 | 700 | return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); |
40c90bca | 701 | |
1f00591e | 702 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 703 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 704 | m.data, &sz); |
17c76198 PP |
705 | if (rc != GNUTLS_E_SUCCESS) |
706 | { | |
707 | free(m.data); | |
708 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
709 | } | |
1f00591e | 710 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 711 | |
f5d25c2b | 712 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 PP |
713 | { |
714 | free(m.data); | |
715 | return tls_error(US"TLS cache write D-H params failed", | |
cf0c6164 | 716 | strerror(errno), NULL, errstr); |
17c76198 | 717 | } |
b5aea5e1 | 718 | free(m.data); |
f5d25c2b | 719 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
17c76198 | 720 | return tls_error(US"TLS cache write D-H params final newline failed", |
cf0c6164 | 721 | strerror(errno), NULL, errstr); |
17c76198 | 722 | |
f5d25c2b | 723 | if ((rc = close(fd))) |
cf0c6164 | 724 | return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); |
059ec3d9 | 725 | |
17c76198 PP |
726 | if (Urename(temp_fn, filename) < 0) |
727 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
cf0c6164 | 728 | temp_fn, filename), strerror(errno), NULL, errstr); |
059ec3d9 | 729 | |
17c76198 | 730 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
731 | } |
732 | ||
17c76198 | 733 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
734 | return OK; |
735 | } | |
736 | ||
737 | ||
738 | ||
739 | ||
23bb6982 JH |
740 | /* Create and install a selfsigned certificate, for use in server mode */ |
741 | ||
742 | static int | |
cf0c6164 | 743 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
744 | { |
745 | gnutls_x509_crt_t cert = NULL; | |
746 | time_t now; | |
747 | gnutls_x509_privkey_t pkey = NULL; | |
748 | const uschar * where; | |
749 | int rc; | |
750 | ||
751 | where = US"initialising pkey"; | |
752 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
753 | ||
754 | where = US"initialising cert"; | |
755 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
756 | ||
757 | where = US"generating pkey"; | |
758 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 759 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
23bb6982 | 760 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), |
76075bb5 JH |
761 | #else |
762 | 1024, | |
763 | #endif | |
764 | 0))) | |
23bb6982 JH |
765 | goto err; |
766 | ||
767 | where = US"configuring cert"; | |
768 | now = 0; | |
769 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) | |
770 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
771 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
772 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
773 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
774 | ||
775 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
776 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
777 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
778 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
779 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
780 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
781 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
782 | ) | |
783 | goto err; | |
784 | ||
785 | where = US"signing cert"; | |
786 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
787 | ||
788 | where = US"installing selfsign cert"; | |
789 | /* Since: 2.4.0 */ | |
790 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
791 | goto err; | |
792 | ||
793 | rc = OK; | |
794 | ||
795 | out: | |
796 | if (cert) gnutls_x509_crt_deinit(cert); | |
797 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
798 | return rc; | |
799 | ||
800 | err: | |
cf0c6164 | 801 | rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); |
23bb6982 JH |
802 | goto out; |
803 | } | |
804 | ||
805 | ||
806 | ||
807 | ||
ba86e143 JH |
808 | static int |
809 | tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, | |
810 | uschar * certfile, uschar * keyfile, uschar ** errstr) | |
811 | { | |
812 | int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, | |
813 | CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); | |
814 | exim_gnutls_err_check( | |
815 | string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile)); | |
816 | return OK; | |
817 | } | |
818 | ||
819 | ||
059ec3d9 | 820 | /************************************************* |
17c76198 | 821 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
822 | *************************************************/ |
823 | ||
17c76198 PP |
824 | /* Called from both server and client code, via tls_init(), and also from |
825 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
826 | ||
827 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
828 | ||
829 | The callback should not call us unless state->trigger_sni_changes is true, | |
830 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
831 | |
832 | Arguments: | |
17c76198 | 833 | state exim_gnutls_state_st * |
cf0c6164 | 834 | errstr error string pointer |
059ec3d9 PH |
835 | |
836 | Returns: OK/DEFER/FAIL | |
837 | */ | |
838 | ||
839 | static int | |
ba86e143 | 840 | tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 841 | { |
1365611d | 842 | struct stat statbuf; |
059ec3d9 | 843 | int rc; |
17c76198 PP |
844 | const host_item *host = state->host; /* macro should be reconsidered? */ |
845 | uschar *saved_tls_certificate = NULL; | |
846 | uschar *saved_tls_privatekey = NULL; | |
847 | uschar *saved_tls_verify_certificates = NULL; | |
848 | uschar *saved_tls_crl = NULL; | |
849 | int cert_count; | |
850 | ||
851 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 852 | if (!host) /* server */ |
17c76198 PP |
853 | if (!state->received_sni) |
854 | { | |
ba86e143 JH |
855 | if ( state->tls_certificate |
856 | && ( Ustrstr(state->tls_certificate, US"tls_sni") | |
857 | || Ustrstr(state->tls_certificate, US"tls_in_sni") | |
858 | || Ustrstr(state->tls_certificate, US"tls_out_sni") | |
859 | ) ) | |
17c76198 PP |
860 | { |
861 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
862 | state->trigger_sni_changes = TRUE; | |
863 | } | |
864 | } | |
865 | else | |
866 | { | |
1365611d | 867 | /* useful for debugging */ |
17c76198 PP |
868 | saved_tls_certificate = state->exp_tls_certificate; |
869 | saved_tls_privatekey = state->exp_tls_privatekey; | |
870 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
871 | saved_tls_crl = state->exp_tls_crl; | |
872 | } | |
059ec3d9 | 873 | |
1365611d PP |
874 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
875 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
876 | ||
17c76198 PP |
877 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
878 | state members, assuming consistent naming; and expand_check() returns | |
879 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 880 | |
17c76198 PP |
881 | /* check if we at least have a certificate, before doing expensive |
882 | D-H generation. */ | |
059ec3d9 | 883 | |
cf0c6164 | 884 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 885 | return DEFER; |
059ec3d9 | 886 | |
17c76198 | 887 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 888 | |
23bb6982 JH |
889 | if ( !state->exp_tls_certificate |
890 | || !*state->exp_tls_certificate | |
891 | ) | |
2b4a568d | 892 | if (!host) |
cf0c6164 | 893 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
894 | else |
895 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 896 | |
cf0c6164 | 897 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
898 | return DEFER; |
899 | ||
17c76198 PP |
900 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
901 | ||
902 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 903 | { |
17c76198 PP |
904 | state->tls_privatekey = state->tls_certificate; |
905 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 906 | } |
c91535f3 | 907 | |
059ec3d9 | 908 | |
17c76198 | 909 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
910 | { |
911 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
912 | state->exp_tls_certificate, state->exp_tls_privatekey); |
913 | ||
914 | if (state->received_sni) | |
23bb6982 JH |
915 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
916 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
917 | ) | |
17c76198 | 918 | { |
b34fc30c | 919 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
920 | } |
921 | else | |
922 | { | |
b34fc30c | 923 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 924 | } |
059ec3d9 | 925 | |
ba86e143 JH |
926 | if (!host) /* server */ |
927 | { | |
928 | const uschar * clist = state->exp_tls_certificate; | |
929 | const uschar * klist = state->exp_tls_privatekey; | |
930 | int csep = 0, ksep = 0; | |
931 | uschar * cfile, * kfile; | |
932 | ||
933 | while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) | |
934 | if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) | |
935 | return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); | |
936 | else if ((rc = tls_add_certfile(state, host, cfile, kfile, errstr))) | |
937 | return rc; | |
938 | else | |
939 | DEBUG(D_tls) debug_printf("TLS: cert/key %s registered\n", cfile); | |
940 | } | |
941 | else | |
942 | { | |
943 | if ((rc = tls_add_certfile(state, host, | |
944 | state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) | |
945 | return rc; | |
946 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
947 | } | |
948 | ||
b34fc30c | 949 | } /* tls_certificate */ |
059ec3d9 | 950 | |
2b4a568d JH |
951 | |
952 | /* Set the OCSP stapling server info */ | |
953 | ||
f2de3a33 | 954 | #ifndef DISABLE_OCSP |
2b4a568d JH |
955 | if ( !host /* server */ |
956 | && tls_ocsp_file | |
957 | ) | |
958 | { | |
9196d5bf JH |
959 | if (gnutls_buggy_ocsp) |
960 | { | |
961 | DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
962 | } | |
963 | else | |
964 | { | |
965 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", | |
cf0c6164 | 966 | &state->exp_tls_ocsp_file, errstr)) |
9196d5bf | 967 | return DEFER; |
2b4a568d | 968 | |
9196d5bf JH |
969 | /* Use the full callback method for stapling just to get observability. |
970 | More efficient would be to read the file once only, if it never changed | |
971 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
44662487 | 972 | |
9196d5bf JH |
973 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, |
974 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 975 | |
9196d5bf JH |
976 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", state->exp_tls_ocsp_file); |
977 | } | |
2b4a568d JH |
978 | } |
979 | #endif | |
980 | ||
981 | ||
059ec3d9 PH |
982 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
983 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
984 | error message is provided. However, if we just refrain from setting anything up | |
985 | in that case, certificate verification fails, which seems to be the correct | |
986 | behaviour. */ | |
987 | ||
610ff438 | 988 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 989 | { |
cf0c6164 | 990 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 991 | return DEFER; |
610ff438 JH |
992 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
993 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
994 | state->exp_tls_verify_certificates = NULL; | |
995 | #endif | |
17c76198 | 996 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 997 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 998 | return DEFER; |
059ec3d9 | 999 | |
1365611d PP |
1000 | if (!(state->exp_tls_verify_certificates && |
1001 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
1002 | { |
1003 | DEBUG(D_tls) | |
1365611d PP |
1004 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
1005 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 1006 | return OK; |
b34fc30c | 1007 | } |
1365611d | 1008 | } |
83e2f8a2 PP |
1009 | else |
1010 | { | |
1011 | DEBUG(D_tls) | |
1012 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
1013 | return OK; | |
1014 | } | |
17c76198 | 1015 | |
cb1d7830 JH |
1016 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
1017 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1018 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
1019 | else | |
1020 | #endif | |
1365611d | 1021 | { |
cb1d7830 JH |
1022 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
1023 | { | |
1024 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
1025 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
1026 | strerror(errno)); | |
1027 | return DEFER; | |
1028 | } | |
17c76198 | 1029 | |
a7fec7a7 | 1030 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1031 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1032 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1033 | other weirdness. The thing we really want to check is that it's not a | |
1034 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1035 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1036 | if (S_ISDIR(statbuf.st_mode)) |
1037 | { | |
1038 | DEBUG(D_tls) | |
1039 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1040 | state->exp_tls_verify_certificates); | |
1041 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1042 | "tls_verify_certificates \"%s\" is a directory", | |
1043 | state->exp_tls_verify_certificates); | |
1044 | return DEFER; | |
1045 | } | |
a7fec7a7 | 1046 | #endif |
059ec3d9 | 1047 | |
cb1d7830 JH |
1048 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1049 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1050 | |
cb1d7830 JH |
1051 | if (statbuf.st_size == 0) |
1052 | { | |
1053 | DEBUG(D_tls) | |
1054 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1055 | return OK; | |
1056 | } | |
059ec3d9 | 1057 | |
cb1d7830 | 1058 | cert_count = |
a7fec7a7 JH |
1059 | |
1060 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1061 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1062 | ? | |
1063 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1064 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1065 | : | |
a7fec7a7 | 1066 | #endif |
cb1d7830 JH |
1067 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1068 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1069 | } | |
a7fec7a7 | 1070 | |
1365611d PP |
1071 | if (cert_count < 0) |
1072 | { | |
1073 | rc = cert_count; | |
cb1d7830 | 1074 | exim_gnutls_err_check(US"setting certificate trust"); |
1365611d PP |
1075 | } |
1076 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1077 | |
5c8cda3a PP |
1078 | if (state->tls_crl && *state->tls_crl && |
1079 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1080 | { |
5c8cda3a PP |
1081 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1082 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1083 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1084 | if (cert_count < 0) | |
1365611d | 1085 | { |
5c8cda3a | 1086 | rc = cert_count; |
1365611d PP |
1087 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
1088 | } | |
5c8cda3a | 1089 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1090 | } |
059ec3d9 | 1091 | |
059ec3d9 PH |
1092 | return OK; |
1093 | } | |
1094 | ||
1095 | ||
1096 | ||
1097 | ||
1365611d PP |
1098 | /************************************************* |
1099 | * Set X.509 state variables * | |
1100 | *************************************************/ | |
1101 | ||
1102 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1103 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1104 | structure. Which means various other non-re-expanded pieces of state | |
1105 | need to be re-set in the new struct, so the setting logic is pulled | |
1106 | out to this. | |
1107 | ||
1108 | Arguments: | |
1109 | state exim_gnutls_state_st * | |
cf0c6164 | 1110 | errstr error string pointer |
1365611d PP |
1111 | |
1112 | Returns: OK/DEFER/FAIL | |
1113 | */ | |
1114 | ||
1115 | static int | |
cf0c6164 | 1116 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1117 | { |
1118 | int rc; | |
1119 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1120 | ||
1121 | /* Create D-H parameters, or read them from the cache file. This function does | |
1122 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1123 | client-side params. */ | |
1124 | ||
1125 | if (!state->host) | |
1126 | { | |
1127 | if (!dh_server_params) | |
1128 | { | |
cf0c6164 | 1129 | rc = init_server_dh(errstr); |
1365611d PP |
1130 | if (rc != OK) return rc; |
1131 | } | |
1132 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1133 | } | |
1134 | ||
1135 | /* Link the credentials to the session. */ | |
1136 | ||
1137 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
1138 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
1139 | ||
1140 | return OK; | |
1141 | } | |
1142 | ||
059ec3d9 | 1143 | /************************************************* |
17c76198 | 1144 | * Initialize for GnuTLS * |
059ec3d9 PH |
1145 | *************************************************/ |
1146 | ||
9196d5bf | 1147 | |
4fb7df6d JH |
1148 | #ifndef DISABLE_OCSP |
1149 | ||
9196d5bf JH |
1150 | static BOOL |
1151 | tls_is_buggy_ocsp(void) | |
1152 | { | |
1153 | const uschar * s; | |
1154 | uschar maj, mid, mic; | |
1155 | ||
1156 | s = CUS gnutls_check_version(NULL); | |
1157 | maj = atoi(CCS s); | |
1158 | if (maj == 3) | |
1159 | { | |
1160 | while (*s && *s != '.') s++; | |
1161 | mid = atoi(CCS ++s); | |
1162 | if (mid <= 2) | |
1163 | return TRUE; | |
1164 | else if (mid >= 5) | |
1165 | return FALSE; | |
1166 | else | |
1167 | { | |
1168 | while (*s && *s != '.') s++; | |
1169 | mic = atoi(CCS ++s); | |
1170 | return mic <= (mid == 3 ? 16 : 3); | |
1171 | } | |
1172 | } | |
1173 | return FALSE; | |
1174 | } | |
1175 | ||
4fb7df6d | 1176 | #endif |
9196d5bf JH |
1177 | |
1178 | ||
17c76198 PP |
1179 | /* Called from both server and client code. In the case of a server, errors |
1180 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1181 | |
1182 | Arguments: | |
17c76198 PP |
1183 | host connected host, if client; NULL if server |
1184 | certificate certificate file | |
1185 | privatekey private key file | |
1186 | sni TLS SNI to send, sometimes when client; else NULL | |
1187 | cas CA certs file | |
1188 | crl CRL file | |
1189 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1190 | caller_state returned state-info structure |
cf0c6164 | 1191 | errstr error string pointer |
059ec3d9 | 1192 | |
17c76198 | 1193 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1194 | */ |
1195 | ||
17c76198 PP |
1196 | static int |
1197 | tls_init( | |
1198 | const host_item *host, | |
1199 | const uschar *certificate, | |
1200 | const uschar *privatekey, | |
1201 | const uschar *sni, | |
1202 | const uschar *cas, | |
1203 | const uschar *crl, | |
1204 | const uschar *require_ciphers, | |
cf0c6164 JH |
1205 | exim_gnutls_state_st **caller_state, |
1206 | uschar ** errstr) | |
059ec3d9 | 1207 | { |
17c76198 PP |
1208 | exim_gnutls_state_st *state; |
1209 | int rc; | |
1210 | size_t sz; | |
1211 | const char *errpos; | |
1212 | uschar *p; | |
1213 | BOOL want_default_priorities; | |
1214 | ||
1215 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1216 | { |
17c76198 PP |
1217 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1218 | ||
a5f239e4 PP |
1219 | #ifdef HAVE_GNUTLS_PKCS11 |
1220 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1221 | which loads modules from a config file, which sounds good and may be wanted | |
1222 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1223 | environment variables are used and so breaks for users calling mailq. | |
1224 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1225 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1226 | { |
1227 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1228 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1229 | } | |
1230 | #endif | |
1231 | ||
17c76198 PP |
1232 | rc = gnutls_global_init(); |
1233 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1234 | ||
1235 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1236 | DEBUG(D_tls) | |
059ec3d9 | 1237 | { |
17c76198 PP |
1238 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1239 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1240 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1241 | } |
17c76198 PP |
1242 | #endif |
1243 | ||
4fb7df6d JH |
1244 | #ifndef DISABLE_OCSP |
1245 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1246 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1247 | #endif |
9196d5bf | 1248 | |
17c76198 | 1249 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1250 | } |
059ec3d9 | 1251 | |
17c76198 PP |
1252 | if (host) |
1253 | { | |
1254 | state = &state_client; | |
1255 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1256 | state->tlsp = &tls_out; |
17c76198 PP |
1257 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1258 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1259 | } | |
1260 | else | |
1261 | { | |
1262 | state = &state_server; | |
1263 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1264 | state->tlsp = &tls_in; |
17c76198 PP |
1265 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1266 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1267 | } | |
1268 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1269 | |
17c76198 | 1270 | state->host = host; |
059ec3d9 | 1271 | |
17c76198 PP |
1272 | state->tls_certificate = certificate; |
1273 | state->tls_privatekey = privatekey; | |
5779e6aa | 1274 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1275 | state->tls_sni = sni; |
1276 | state->tls_verify_certificates = cas; | |
1277 | state->tls_crl = crl; | |
059ec3d9 | 1278 | |
17c76198 PP |
1279 | /* This handles the variables that might get re-expanded after TLS SNI; |
1280 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1281 | |
17c76198 PP |
1282 | DEBUG(D_tls) |
1283 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1284 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1285 | |
1365611d PP |
1286 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1287 | requires a new structure afterwards. */ | |
83da1223 | 1288 | |
cf0c6164 | 1289 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1290 | |
17c76198 PP |
1291 | /* set SNI in client, only */ |
1292 | if (host) | |
1293 | { | |
cf0c6164 | 1294 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1295 | return DEFER; |
0df4ab80 | 1296 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1297 | { |
1298 | DEBUG(D_tls) | |
0df4ab80 JH |
1299 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1300 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1301 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1302 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
17c76198 PP |
1303 | exim_gnutls_err_check(US"gnutls_server_name_set"); |
1304 | } | |
1305 | } | |
1306 | else if (state->tls_sni) | |
1307 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
ba86e143 | 1308 | "have an SNI set for a server [%s]\n", state->tls_sni); |
83da1223 | 1309 | |
17c76198 | 1310 | /* This is the priority string support, |
42bfef1e | 1311 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1312 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1313 | This was backwards incompatible, but means Exim no longer needs to track | |
1314 | all algorithms and provide string forms for them. */ | |
83da1223 | 1315 | |
17c76198 | 1316 | want_default_priorities = TRUE; |
83da1223 | 1317 | |
17c76198 | 1318 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1319 | { |
cf0c6164 | 1320 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1321 | return DEFER; |
1322 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1323 | { |
17c76198 PP |
1324 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1325 | state->exp_tls_require_ciphers); | |
1326 | ||
1327 | rc = gnutls_priority_init(&state->priority_cache, | |
1328 | CS state->exp_tls_require_ciphers, &errpos); | |
1329 | want_default_priorities = FALSE; | |
1330 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1331 | } |
1332 | } | |
17c76198 PP |
1333 | if (want_default_priorities) |
1334 | { | |
83e2f8a2 PP |
1335 | DEBUG(D_tls) |
1336 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1337 | exim_default_gnutls_priority); | |
17c76198 PP |
1338 | rc = gnutls_priority_init(&state->priority_cache, |
1339 | exim_default_gnutls_priority, &errpos); | |
1340 | p = US exim_default_gnutls_priority; | |
1341 | } | |
83da1223 | 1342 | |
17c76198 PP |
1343 | exim_gnutls_err_check(string_sprintf( |
1344 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1345 | p, errpos - CS p, errpos)); | |
1346 | ||
1347 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1348 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1349 | ||
1350 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1351 | ||
1352 | /* Reduce security in favour of increased compatibility, if the admin | |
1353 | decides to make that trade-off. */ | |
1354 | if (gnutls_compat_mode) | |
83da1223 | 1355 | { |
17c76198 PP |
1356 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1357 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1358 | gnutls_session_enable_compatibility_mode(state->session); | |
1359 | #else | |
1360 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1361 | #endif | |
83da1223 PH |
1362 | } |
1363 | ||
17c76198 | 1364 | *caller_state = state; |
17c76198 | 1365 | return OK; |
83da1223 PH |
1366 | } |
1367 | ||
1368 | ||
1369 | ||
059ec3d9 | 1370 | /************************************************* |
17c76198 | 1371 | * Extract peer information * |
059ec3d9 PH |
1372 | *************************************************/ |
1373 | ||
17c76198 | 1374 | /* Called from both server and client code. |
4fe99a6c PP |
1375 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1376 | and we use that to detect double-calls. | |
059ec3d9 | 1377 | |
75fe387d PP |
1378 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1379 | for logging in the server side, but for the client side, we log after teardown | |
1380 | in src/deliver.c. While the session is up, we can twist about states and | |
1381 | repoint tls_* globals, but those variables used for logging or other variable | |
1382 | expansion that happens _after_ delivery need to have a longer life-time. | |
1383 | ||
1384 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1385 | doing this more than once per generation of a state context. We set them in | |
1386 | the state context, and repoint tls_* to them. After the state goes away, the | |
1387 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1388 | ||
1389 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1390 | don't apply. | |
1391 | ||
059ec3d9 | 1392 | Arguments: |
17c76198 | 1393 | state exim_gnutls_state_st * |
cf0c6164 | 1394 | errstr pointer to error string |
059ec3d9 | 1395 | |
17c76198 | 1396 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1397 | */ |
1398 | ||
17c76198 | 1399 | static int |
cf0c6164 | 1400 | peer_status(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 1401 | { |
75fe387d | 1402 | uschar cipherbuf[256]; |
27f19eb4 | 1403 | const gnutls_datum_t *cert_list; |
75fe387d | 1404 | int old_pool, rc; |
17c76198 | 1405 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1406 | gnutls_protocol_t protocol; |
1407 | gnutls_cipher_algorithm_t cipher; | |
1408 | gnutls_kx_algorithm_t kx; | |
1409 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1410 | gnutls_certificate_type_t ct; |
1411 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1412 | uschar *p, *dn_buf; |
17c76198 | 1413 | size_t sz; |
059ec3d9 | 1414 | |
4fe99a6c | 1415 | if (state->have_set_peerdn) |
17c76198 | 1416 | return OK; |
4fe99a6c | 1417 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1418 | |
4fe99a6c | 1419 | state->peerdn = NULL; |
059ec3d9 | 1420 | |
4fe99a6c PP |
1421 | /* tls_cipher */ |
1422 | cipher = gnutls_cipher_get(state->session); | |
1423 | protocol = gnutls_protocol_get_version(state->session); | |
1424 | mac = gnutls_mac_get(state->session); | |
1425 | kx = gnutls_kx_get(state->session); | |
1426 | ||
75fe387d | 1427 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1428 | "%s:%s:%d", |
1429 | gnutls_protocol_get_name(protocol), | |
1430 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1431 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1432 | ||
1433 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1434 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1435 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1436 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1437 | if (isspace(*p)) |
1438 | *p = '-'; | |
75fe387d PP |
1439 | old_pool = store_pool; |
1440 | store_pool = POOL_PERM; | |
1441 | state->ciphersuite = string_copy(cipherbuf); | |
1442 | store_pool = old_pool; | |
817d9f57 | 1443 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1444 | |
1445 | /* tls_peerdn */ | |
17c76198 | 1446 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1447 | |
17c76198 PP |
1448 | if (cert_list == NULL || cert_list_size == 0) |
1449 | { | |
17c76198 PP |
1450 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1451 | cert_list, cert_list_size); | |
e51c7be2 | 1452 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1453 | return tls_error(US"certificate verification failed", |
cf0c6164 | 1454 | "no certificate received from peer", state->host, errstr); |
17c76198 PP |
1455 | return OK; |
1456 | } | |
059ec3d9 | 1457 | |
17c76198 PP |
1458 | ct = gnutls_certificate_type_get(state->session); |
1459 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1460 | { |
17c76198 | 1461 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1462 | DEBUG(D_tls) |
1463 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1464 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1465 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1466 | ctn, state->host, errstr); |
17c76198 | 1467 | return OK; |
83da1223 | 1468 | } |
059ec3d9 | 1469 | |
e51c7be2 JH |
1470 | #define exim_gnutls_peer_err(Label) \ |
1471 | do { \ | |
1472 | if (rc != GNUTLS_E_SUCCESS) \ | |
1473 | { \ | |
1474 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1475 | (Label), gnutls_strerror(rc)); \ | |
1476 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
cf0c6164 | 1477 | return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ |
e51c7be2 JH |
1478 | return OK; \ |
1479 | } \ | |
1480 | } while (0) | |
17c76198 | 1481 | |
9d1c15ef JH |
1482 | rc = import_cert(&cert_list[0], &crt); |
1483 | exim_gnutls_peer_err(US"cert 0"); | |
1484 | ||
1485 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1486 | |
17c76198 PP |
1487 | sz = 0; |
1488 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1489 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1490 | { |
17c76198 PP |
1491 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1492 | return FAIL; /* should not happen */ | |
059ec3d9 | 1493 | } |
17c76198 PP |
1494 | dn_buf = store_get_perm(sz); |
1495 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1496 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1497 | |
17c76198 PP |
1498 | state->peerdn = dn_buf; |
1499 | ||
1500 | return OK; | |
1501 | #undef exim_gnutls_peer_err | |
1502 | } | |
059ec3d9 | 1503 | |
059ec3d9 | 1504 | |
059ec3d9 | 1505 | |
059ec3d9 | 1506 | |
17c76198 PP |
1507 | /************************************************* |
1508 | * Verify peer certificate * | |
1509 | *************************************************/ | |
059ec3d9 | 1510 | |
17c76198 PP |
1511 | /* Called from both server and client code. |
1512 | *Should* be using a callback registered with | |
1513 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1514 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1515 | |
17c76198 PP |
1516 | Arguments: |
1517 | state exim_gnutls_state_st * | |
cf0c6164 | 1518 | errstr where to put an error message |
059ec3d9 | 1519 | |
17c76198 PP |
1520 | Returns: |
1521 | FALSE if the session should be rejected | |
1522 | TRUE if the cert is okay or we just don't care | |
1523 | */ | |
059ec3d9 | 1524 | |
17c76198 | 1525 | static BOOL |
cf0c6164 | 1526 | verify_certificate(exim_gnutls_state_st *state, uschar ** errstr) |
17c76198 PP |
1527 | { |
1528 | int rc; | |
1529 | unsigned int verify; | |
1530 | ||
cf0c6164 | 1531 | *errstr = NULL; |
17c76198 | 1532 | |
cf0c6164 | 1533 | if ((rc = peer_status(state, errstr)) != OK) |
e6060e2c | 1534 | { |
17c76198 | 1535 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1536 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1537 | } |
1538 | else | |
17c76198 | 1539 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1540 | |
17c76198 PP |
1541 | /* Handle the result of verification. INVALID seems to be set as well |
1542 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1543 | |
e51c7be2 JH |
1544 | if (rc < 0 || |
1545 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1546 | ) | |
17c76198 PP |
1547 | { |
1548 | state->peer_cert_verified = FALSE; | |
cf0c6164 JH |
1549 | if (!*errstr) |
1550 | *errstr = verify & GNUTLS_CERT_REVOKED | |
1551 | ? US"certificate revoked" : US"certificate invalid"; | |
059ec3d9 | 1552 | |
17c76198 | 1553 | DEBUG(D_tls) |
e51c7be2 | 1554 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1555 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1556 | |
e51c7be2 | 1557 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1558 | { |
e51c7be2 JH |
1559 | gnutls_alert_send(state->session, |
1560 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1561 | return FALSE; |
1562 | } | |
1563 | DEBUG(D_tls) | |
4789da3a | 1564 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1565 | } |
e51c7be2 | 1566 | |
17c76198 PP |
1567 | else |
1568 | { | |
aa2a70ba | 1569 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1570 | { |
1571 | int sep = 0; | |
55414b25 | 1572 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 | 1573 | uschar * name; |
76075bb5 | 1574 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) |
e51c7be2 JH |
1575 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) |
1576 | break; | |
1577 | if (!name) | |
1578 | { | |
1579 | DEBUG(D_tls) | |
1580 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba JH |
1581 | if (state->verify_requirement >= VERIFY_REQUIRED) |
1582 | { | |
1583 | gnutls_alert_send(state->session, | |
1584 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1585 | return FALSE; | |
1586 | } | |
1587 | return TRUE; | |
e51c7be2 JH |
1588 | } |
1589 | } | |
17c76198 | 1590 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1591 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1592 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1593 | } |
059ec3d9 | 1594 | |
817d9f57 | 1595 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1596 | |
17c76198 PP |
1597 | return TRUE; |
1598 | } | |
059ec3d9 | 1599 | |
17c76198 PP |
1600 | |
1601 | ||
1602 | ||
1603 | /* ------------------------------------------------------------------------ */ | |
1604 | /* Callbacks */ | |
1605 | ||
1606 | /* Logging function which can be registered with | |
1607 | * gnutls_global_set_log_function() | |
1608 | * gnutls_global_set_log_level() 0..9 | |
1609 | */ | |
af3498d6 | 1610 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1611 | static void |
17c76198 | 1612 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1613 | { |
8c79eebf PP |
1614 | size_t len = strlen(message); |
1615 | if (len < 1) | |
1616 | { | |
1617 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1618 | return; | |
1619 | } | |
1620 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1621 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1622 | } |
af3498d6 | 1623 | #endif |
059ec3d9 | 1624 | |
059ec3d9 | 1625 | |
17c76198 PP |
1626 | /* Called after client hello, should handle SNI work. |
1627 | This will always set tls_sni (state->received_sni) if available, | |
1628 | and may trigger presenting different certificates, | |
1629 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1630 | |
17c76198 PP |
1631 | Should be registered with |
1632 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1633 | |
17c76198 PP |
1634 | "This callback must return 0 on success or a gnutls error code to terminate the |
1635 | handshake.". | |
059ec3d9 | 1636 | |
17c76198 PP |
1637 | For inability to get SNI information, we return 0. |
1638 | We only return non-zero if re-setup failed. | |
817d9f57 | 1639 | Only used for server-side TLS. |
17c76198 | 1640 | */ |
44bbabb5 | 1641 | |
17c76198 PP |
1642 | static int |
1643 | exim_sni_handling_cb(gnutls_session_t session) | |
1644 | { | |
1645 | char sni_name[MAX_HOST_LEN]; | |
1646 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1647 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1648 | unsigned int sni_type; |
1649 | int rc, old_pool; | |
cf0c6164 | 1650 | uschar * dummy_errstr; |
17c76198 PP |
1651 | |
1652 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1653 | if (rc != GNUTLS_E_SUCCESS) |
1654 | { | |
1655 | DEBUG(D_tls) { | |
1656 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1657 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1658 | else | |
1659 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1660 | gnutls_strerror(rc), rc); | |
cf0c6164 | 1661 | } |
b34fc30c PP |
1662 | return 0; |
1663 | } | |
1664 | ||
17c76198 PP |
1665 | if (sni_type != GNUTLS_NAME_DNS) |
1666 | { | |
1667 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1668 | return 0; | |
1669 | } | |
44bbabb5 | 1670 | |
17c76198 PP |
1671 | /* We now have a UTF-8 string in sni_name */ |
1672 | old_pool = store_pool; | |
1673 | store_pool = POOL_PERM; | |
1674 | state->received_sni = string_copyn(US sni_name, data_len); | |
1675 | store_pool = old_pool; | |
1676 | ||
1677 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1678 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1679 | |
1680 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1681 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1682 | ||
1683 | if (!state->trigger_sni_changes) | |
1684 | return 0; | |
1685 | ||
cf0c6164 | 1686 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
1687 | { |
1688 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1689 | been offered. The best we can do now is abort. */ | |
1690 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1691 | } | |
1692 | ||
cf0c6164 | 1693 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
1694 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
1695 | ||
1696 | return 0; | |
059ec3d9 PH |
1697 | } |
1698 | ||
1699 | ||
1700 | ||
f2de3a33 | 1701 | #ifndef DISABLE_OCSP |
44662487 JH |
1702 | |
1703 | static int | |
1704 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1705 | gnutls_datum_t * ocsp_response) | |
1706 | { | |
1707 | int ret; | |
1708 | ||
44662487 JH |
1709 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1710 | { | |
1711 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
5903c6ff | 1712 | CS ptr); |
018058b2 | 1713 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1714 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1715 | } | |
1716 | ||
018058b2 | 1717 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1718 | return 0; |
1719 | } | |
1720 | ||
1721 | #endif | |
1722 | ||
1723 | ||
0cbf2b82 | 1724 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1725 | /* |
1726 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1727 | for an exim TLS connection (either direction), raising a tls:cert event |
1728 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1729 | can deny verification. |
1730 | ||
1731 | Return 0 for the handshake to continue or non-zero to terminate. | |
1732 | */ | |
1733 | ||
1734 | static int | |
723fe533 | 1735 | verify_cb(gnutls_session_t session) |
a7538db1 | 1736 | { |
27f19eb4 | 1737 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1738 | unsigned int cert_list_size = 0; |
1739 | gnutls_x509_crt_t crt; | |
1740 | int rc; | |
b30275b8 | 1741 | uschar * yield; |
a7538db1 JH |
1742 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1743 | ||
1744 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1745 | if (cert_list) | |
1746 | while (cert_list_size--) | |
1747 | { | |
1748 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1749 | if (rc != GNUTLS_E_SUCCESS) | |
1750 | { | |
1751 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1752 | cert_list_size, gnutls_strerror(rc)); | |
1753 | break; | |
1754 | } | |
1755 | ||
1756 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1757 | if ((yield = event_raise(state->event_action, |
1758 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1759 | { |
1760 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1761 | "SSL verify denied by event-action: depth=%d: %s", |
1762 | cert_list_size, yield); | |
a7538db1 JH |
1763 | return 1; /* reject */ |
1764 | } | |
1765 | state->tlsp->peercert = NULL; | |
1766 | } | |
1767 | ||
1768 | return 0; | |
1769 | } | |
1770 | ||
1771 | #endif | |
44662487 JH |
1772 | |
1773 | ||
17c76198 PP |
1774 | |
1775 | /* ------------------------------------------------------------------------ */ | |
1776 | /* Exported functions */ | |
1777 | ||
1778 | ||
1779 | ||
1780 | ||
059ec3d9 PH |
1781 | /************************************************* |
1782 | * Start a TLS session in a server * | |
1783 | *************************************************/ | |
1784 | ||
1785 | /* This is called when Exim is running as a server, after having received | |
1786 | the STARTTLS command. It must respond to that command, and then negotiate | |
1787 | a TLS session. | |
1788 | ||
1789 | Arguments: | |
83da1223 | 1790 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 1791 | errstr pointer to error string |
059ec3d9 PH |
1792 | |
1793 | Returns: OK on success | |
1794 | DEFER for errors before the start of the negotiation | |
4c04137d | 1795 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
1796 | continue running. |
1797 | */ | |
1798 | ||
1799 | int | |
cf0c6164 | 1800 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
1801 | { |
1802 | int rc; | |
cf0c6164 | 1803 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
1804 | |
1805 | /* Check for previous activation */ | |
817d9f57 | 1806 | if (tls_in.active >= 0) |
059ec3d9 | 1807 | { |
cf0c6164 | 1808 | tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); |
925ac8e4 | 1809 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
1810 | return FAIL; |
1811 | } | |
1812 | ||
1813 | /* Initialize the library. If it fails, it will already have logged the error | |
1814 | and sent an SMTP response. */ | |
1815 | ||
17c76198 | 1816 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1817 | |
cf0c6164 | 1818 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 1819 | NULL, tls_verify_certificates, tls_crl, |
cf0c6164 | 1820 | require_ciphers, &state, errstr)) != OK) return rc; |
059ec3d9 | 1821 | |
059ec3d9 PH |
1822 | /* If this is a host for which certificate verification is mandatory or |
1823 | optional, set up appropriately. */ | |
1824 | ||
059ec3d9 | 1825 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1826 | { |
e51c7be2 JH |
1827 | DEBUG(D_tls) |
1828 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1829 | state->verify_requirement = VERIFY_REQUIRED; |
1830 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1831 | } | |
059ec3d9 | 1832 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1833 | { |
e51c7be2 JH |
1834 | DEBUG(D_tls) |
1835 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1836 | state->verify_requirement = VERIFY_OPTIONAL; |
1837 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1838 | } | |
1839 | else | |
1840 | { | |
e51c7be2 JH |
1841 | DEBUG(D_tls) |
1842 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1843 | state->verify_requirement = VERIFY_NONE; |
1844 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1845 | } | |
059ec3d9 | 1846 | |
0cbf2b82 | 1847 | #ifndef DISABLE_EVENT |
723fe533 JH |
1848 | if (event_action) |
1849 | { | |
1850 | state->event_action = event_action; | |
1851 | gnutls_session_set_ptr(state->session, state); | |
1852 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
1853 | } | |
1854 | #endif | |
1855 | ||
17c76198 PP |
1856 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1857 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1858 | |
17c76198 PP |
1859 | gnutls_handshake_set_post_client_hello_function(state->session, |
1860 | exim_sni_handling_cb); | |
059ec3d9 PH |
1861 | |
1862 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1863 | on connection, where outputting anything now upsets the clients and tends to | |
1864 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1865 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1866 | mode, the fflush() happens when smtp_getc() is called. */ | |
1867 | ||
817d9f57 | 1868 | if (!state->tlsp->on_connect) |
059ec3d9 | 1869 | { |
925ac8e4 | 1870 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 1871 | fflush(smtp_out); |
059ec3d9 PH |
1872 | } |
1873 | ||
1874 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1875 | that the GnuTLS library doesn't. */ | |
1876 | ||
17c76198 | 1877 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
1878 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
1879 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
1880 | state->fd_in = fileno(smtp_in); |
1881 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1882 | |
1883 | sigalrm_seen = FALSE; | |
1884 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1885 | do |
17c76198 | 1886 | rc = gnutls_handshake(state->session); |
157a7880 | 1887 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
1888 | alarm(0); |
1889 | ||
17c76198 | 1890 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1891 | { |
059ec3d9 PH |
1892 | /* It seems that, except in the case of a timeout, we have to close the |
1893 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1894 | until the server times out. */ | |
1895 | ||
60d10ce7 | 1896 | if (sigalrm_seen) |
ad7fc6eb | 1897 | { |
cf0c6164 | 1898 | tls_error(US"gnutls_handshake", "timed out", NULL, errstr); |
ad7fc6eb JH |
1899 | gnutls_db_remove_session(state->session); |
1900 | } | |
60d10ce7 | 1901 | else |
059ec3d9 | 1902 | { |
cf0c6164 | 1903 | tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); |
f5d25c2b | 1904 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 1905 | gnutls_deinit(state->session); |
ed62aae3 | 1906 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 1907 | millisleep(500); |
ad7fc6eb | 1908 | shutdown(state->fd_out, SHUT_WR); |
60d10ce7 | 1909 | for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ |
f1e894f3 PH |
1910 | (void)fclose(smtp_out); |
1911 | (void)fclose(smtp_in); | |
60d10ce7 | 1912 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
1913 | } |
1914 | ||
1915 | return FAIL; | |
1916 | } | |
1917 | ||
1918 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1919 | ||
17c76198 PP |
1920 | /* Verify after the fact */ |
1921 | ||
9d1c15ef | 1922 | if ( state->verify_requirement != VERIFY_NONE |
cf0c6164 | 1923 | && !verify_certificate(state, errstr)) |
059ec3d9 | 1924 | { |
9d1c15ef | 1925 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1926 | { |
cf0c6164 | 1927 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 1928 | return FAIL; |
17c76198 | 1929 | } |
9d1c15ef JH |
1930 | DEBUG(D_tls) |
1931 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 1932 | *errstr); |
059ec3d9 PH |
1933 | } |
1934 | ||
17c76198 PP |
1935 | /* Figure out peer DN, and if authenticated, etc. */ |
1936 | ||
cf0c6164 | 1937 | if ((rc = peer_status(state, NULL)) != OK) return rc; |
17c76198 PP |
1938 | |
1939 | /* Sets various Exim expansion variables; always safe within server */ | |
1940 | ||
9d1c15ef | 1941 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1942 | |
1943 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1944 | and initialize appropriately. */ | |
1945 | ||
17c76198 | 1946 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1947 | |
1948 | receive_getc = tls_getc; | |
0d81dabc | 1949 | receive_getbuf = tls_getbuf; |
584e96c6 | 1950 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
1951 | receive_ungetc = tls_ungetc; |
1952 | receive_feof = tls_feof; | |
1953 | receive_ferror = tls_ferror; | |
58eb016e | 1954 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1955 | |
059ec3d9 PH |
1956 | return OK; |
1957 | } | |
1958 | ||
1959 | ||
1960 | ||
1961 | ||
aa2a70ba JH |
1962 | static void |
1963 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
1964 | smtp_transport_options_block * ob) | |
1965 | { | |
5130845b | 1966 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 1967 | { |
4af0d74a | 1968 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 1969 | #ifdef SUPPORT_I18N |
4af0d74a JH |
1970 | string_domain_utf8_to_alabel(host->name, NULL); |
1971 | #else | |
1972 | host->name; | |
1973 | #endif | |
aa2a70ba JH |
1974 | DEBUG(D_tls) |
1975 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
1976 | state->exp_tls_verify_cert_hostnames); | |
1977 | } | |
1978 | } | |
aa2a70ba JH |
1979 | |
1980 | ||
059ec3d9 PH |
1981 | /************************************************* |
1982 | * Start a TLS session in a client * | |
1983 | *************************************************/ | |
1984 | ||
1985 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1986 | ||
1987 | Arguments: | |
1988 | fd the fd of the connection | |
1989 | host connected host (for messages) | |
83da1223 | 1990 | addr the first address (not used) |
a7538db1 | 1991 | tb transport (always smtp) |
059ec3d9 | 1992 | |
cf0c6164 JH |
1993 | errstr error string pointer |
1994 | ||
059ec3d9 PH |
1995 | Returns: OK/DEFER/FAIL (because using common functions), |
1996 | but for a client, DEFER and FAIL have the same meaning | |
1997 | */ | |
1998 | ||
1999 | int | |
17c76198 | 2000 | tls_client_start(int fd, host_item *host, |
f5d78688 | 2001 | address_item *addr ARG_UNUSED, |
cf0c6164 | 2002 | transport_instance * tb, |
0e66b3b6 | 2003 | #ifdef EXPERIMENTAL_DANE |
cf0c6164 | 2004 | dns_answer * tlsa_dnsa ARG_UNUSED, |
0e66b3b6 | 2005 | #endif |
cf0c6164 | 2006 | uschar ** errstr) |
059ec3d9 | 2007 | { |
a7538db1 JH |
2008 | smtp_transport_options_block *ob = |
2009 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 2010 | int rc; |
17c76198 | 2011 | exim_gnutls_state_st *state = NULL; |
f2de3a33 | 2012 | #ifndef DISABLE_OCSP |
5130845b JH |
2013 | BOOL require_ocsp = |
2014 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 2015 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 2016 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 2017 | #endif |
059ec3d9 | 2018 | |
17c76198 | 2019 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 2020 | |
65867078 JH |
2021 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
2022 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
cf0c6164 | 2023 | ob->tls_require_ciphers, &state, errstr)) != OK) |
2b4a568d | 2024 | return rc; |
059ec3d9 | 2025 | |
54c90be1 | 2026 | { |
65867078 JH |
2027 | int dh_min_bits = ob->tls_dh_min_bits; |
2028 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2029 | { | |
2030 | DEBUG(D_tls) | |
2031 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2032 | " clamping %d up to %d\n", | |
2033 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2034 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2035 | } | |
54c90be1 | 2036 | |
65867078 JH |
2037 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2038 | " acceptable bits to %d\n", | |
2039 | dh_min_bits); | |
2040 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2041 | } | |
83da1223 | 2042 | |
94431adb | 2043 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2044 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2045 | the specified host patterns if one of them is defined */ | |
2046 | ||
aa2a70ba JH |
2047 | if ( ( state->exp_tls_verify_certificates |
2048 | && !ob->tls_verify_hosts | |
610ff438 | 2049 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) |
aa2a70ba | 2050 | ) |
5130845b | 2051 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK |
2b4a568d | 2052 | ) |
17c76198 | 2053 | { |
aa2a70ba | 2054 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2055 | DEBUG(D_tls) |
2056 | debug_printf("TLS: server certificate verification required.\n"); | |
2057 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2058 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2059 | } | |
5130845b | 2060 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2061 | { |
aa2a70ba | 2062 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2063 | DEBUG(D_tls) |
2064 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2065 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2066 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2067 | } | |
2068 | else | |
2069 | { | |
e51c7be2 JH |
2070 | DEBUG(D_tls) |
2071 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2072 | state->verify_requirement = VERIFY_NONE; |
2073 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2074 | } |
059ec3d9 | 2075 | |
f2de3a33 JH |
2076 | #ifndef DISABLE_OCSP |
2077 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2078 | if (request_ocsp) |
9d1c15ef JH |
2079 | { |
2080 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2081 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2082 | NULL, 0, NULL)) != OK) | |
9d1c15ef | 2083 | return tls_error(US"cert-status-req", |
cf0c6164 | 2084 | gnutls_strerror(rc), state->host, errstr); |
44662487 | 2085 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2086 | } |
2b4a568d JH |
2087 | #endif |
2088 | ||
0cbf2b82 | 2089 | #ifndef DISABLE_EVENT |
774ef2d7 | 2090 | if (tb->event_action) |
a7538db1 | 2091 | { |
774ef2d7 | 2092 | state->event_action = tb->event_action; |
a7538db1 | 2093 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2094 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2095 | } |
2096 | #endif | |
2097 | ||
27f19eb4 | 2098 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2099 | state->fd_in = fd; |
2100 | state->fd_out = fd; | |
059ec3d9 | 2101 | |
9d1c15ef | 2102 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2103 | /* There doesn't seem to be a built-in timeout on connection. */ |
2104 | ||
2105 | sigalrm_seen = FALSE; | |
65867078 | 2106 | alarm(ob->command_timeout); |
17c76198 PP |
2107 | do |
2108 | { | |
2109 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
2110 | } while ((rc == GNUTLS_E_AGAIN) || |
2111 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
2112 | alarm(0); |
2113 | ||
4fe99a6c | 2114 | if (rc != GNUTLS_E_SUCCESS) |
60d10ce7 JH |
2115 | if (sigalrm_seen) |
2116 | { | |
2117 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
cf0c6164 | 2118 | return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); |
60d10ce7 JH |
2119 | } |
2120 | else | |
cf0c6164 | 2121 | return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); |
4fe99a6c | 2122 | |
17c76198 | 2123 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2124 | |
17c76198 | 2125 | /* Verify late */ |
059ec3d9 | 2126 | |
17c76198 | 2127 | if (state->verify_requirement != VERIFY_NONE && |
cf0c6164 JH |
2128 | !verify_certificate(state, errstr)) |
2129 | return tls_error(US"certificate verification failed", *errstr, state->host, errstr); | |
059ec3d9 | 2130 | |
f2de3a33 | 2131 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2132 | if (require_ocsp) |
2133 | { | |
2134 | DEBUG(D_tls) | |
2135 | { | |
2136 | gnutls_datum_t stapling; | |
2137 | gnutls_ocsp_resp_t resp; | |
2138 | gnutls_datum_t printed; | |
2139 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2140 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2141 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2142 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2143 | ) | |
2144 | { | |
65867078 | 2145 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2146 | gnutls_free(printed.data); |
2147 | } | |
2148 | else | |
cf0c6164 | 2149 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host, errstr); |
2b4a568d JH |
2150 | } |
2151 | ||
2b4a568d | 2152 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2153 | { |
2154 | tls_out.ocsp = OCSP_FAILED; | |
cf0c6164 | 2155 | return tls_error(US"certificate status check failed", NULL, state->host, errstr); |
018058b2 | 2156 | } |
2b4a568d | 2157 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2158 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2159 | } |
2160 | #endif | |
2161 | ||
17c76198 | 2162 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2163 | |
cf0c6164 | 2164 | if ((rc = peer_status(state, errstr)) != OK) |
2b4a568d | 2165 | return rc; |
059ec3d9 | 2166 | |
4fe99a6c | 2167 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2168 | |
9d1c15ef | 2169 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2170 | |
059ec3d9 PH |
2171 | return OK; |
2172 | } | |
2173 | ||
2174 | ||
2175 | ||
17c76198 | 2176 | |
059ec3d9 | 2177 | /************************************************* |
17c76198 | 2178 | * Close down a TLS session * |
059ec3d9 PH |
2179 | *************************************************/ |
2180 | ||
17c76198 PP |
2181 | /* This is also called from within a delivery subprocess forked from the |
2182 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2183 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2184 | |
17c76198 PP |
2185 | Arguments: TRUE if gnutls_bye is to be called |
2186 | Returns: nothing | |
059ec3d9 PH |
2187 | */ |
2188 | ||
17c76198 | 2189 | void |
817d9f57 | 2190 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2191 | { |
817d9f57 | 2192 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2193 | |
389ca47a | 2194 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2195 | |
2196 | if (shutdown) | |
2197 | { | |
f5723109 | 2198 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); |
17c76198 PP |
2199 | gnutls_bye(state->session, GNUTLS_SHUT_WR); |
2200 | } | |
2201 | ||
2202 | gnutls_deinit(state->session); | |
ed62aae3 HSHR |
2203 | gnutls_certificate_free_credentials(state->x509_cred); |
2204 | ||
17c76198 | 2205 | |
389ca47a | 2206 | state->tlsp->active = -1; |
17c76198 PP |
2207 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2208 | ||
2209 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2210 | { | |
2211 | gnutls_global_deinit(); | |
2212 | exim_gnutls_base_init_done = FALSE; | |
2213 | } | |
059ec3d9 PH |
2214 | } |
2215 | ||
2216 | ||
2217 | ||
17c76198 | 2218 | |
0d81dabc JH |
2219 | static BOOL |
2220 | tls_refill(unsigned lim) | |
2221 | { | |
2222 | exim_gnutls_state_st * state = &state_server; | |
2223 | ssize_t inbytes; | |
2224 | ||
2225 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2226 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2227 | ||
2228 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
2229 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2230 | MIN(ssl_xfer_buffer_size, lim)); | |
2231 | alarm(0); | |
2232 | ||
2233 | /* Timeouts do not get this far; see command_timeout_handler(). | |
2234 | A zero-byte return appears to mean that the TLS session has been | |
2235 | closed down, not that the socket itself has been closed down. Revert to | |
2236 | non-TLS handling. */ | |
2237 | ||
2238 | if (sigalrm_seen) | |
2239 | { | |
2240 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
2241 | state->xfer_error = 1; | |
2242 | return FALSE; | |
2243 | } | |
2244 | ||
2245 | else if (inbytes == 0) | |
2246 | { | |
2247 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2248 | ||
2249 | receive_getc = smtp_getc; | |
2250 | receive_getbuf = smtp_getbuf; | |
2251 | receive_get_cache = smtp_get_cache; | |
2252 | receive_ungetc = smtp_ungetc; | |
2253 | receive_feof = smtp_feof; | |
2254 | receive_ferror = smtp_ferror; | |
2255 | receive_smtp_buffered = smtp_buffered; | |
2256 | ||
2257 | gnutls_deinit(state->session); | |
2258 | gnutls_certificate_free_credentials(state->x509_cred); | |
2259 | ||
2260 | state->session = NULL; | |
2261 | state->tlsp->active = -1; | |
2262 | state->tlsp->bits = 0; | |
2263 | state->tlsp->certificate_verified = FALSE; | |
2264 | tls_channelbinding_b64 = NULL; | |
2265 | state->tlsp->cipher = NULL; | |
2266 | state->tlsp->peercert = NULL; | |
2267 | state->tlsp->peerdn = NULL; | |
2268 | ||
2269 | return FALSE; | |
2270 | } | |
2271 | ||
2272 | /* Handle genuine errors */ | |
2273 | ||
2274 | else if (inbytes < 0) | |
2275 | { | |
2276 | record_io_error(state, (int) inbytes, US"recv", NULL); | |
2277 | state->xfer_error = 1; | |
2278 | return FALSE; | |
2279 | } | |
2280 | #ifndef DISABLE_DKIM | |
2281 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
2282 | #endif | |
2283 | state->xfer_buffer_hwm = (int) inbytes; | |
2284 | state->xfer_buffer_lwm = 0; | |
2285 | return TRUE; | |
2286 | } | |
2287 | ||
059ec3d9 PH |
2288 | /************************************************* |
2289 | * TLS version of getc * | |
2290 | *************************************************/ | |
2291 | ||
2292 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2293 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2294 | Only used by the server-side TLS. |
059ec3d9 | 2295 | |
17c76198 PP |
2296 | This feeds DKIM and should be used for all message-body reads. |
2297 | ||
bd8fbe36 | 2298 | Arguments: lim Maximum amount to read/bufffer |
059ec3d9 PH |
2299 | Returns: the next character or EOF |
2300 | */ | |
2301 | ||
2302 | int | |
bd8fbe36 | 2303 | tls_getc(unsigned lim) |
059ec3d9 | 2304 | { |
0d81dabc | 2305 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 2306 | |
0d81dabc JH |
2307 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2308 | if (!tls_refill(lim)) | |
2309 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 2310 | |
0d81dabc | 2311 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2312 | |
0d81dabc JH |
2313 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
2314 | } | |
059ec3d9 | 2315 | |
0d81dabc JH |
2316 | uschar * |
2317 | tls_getbuf(unsigned * len) | |
2318 | { | |
2319 | exim_gnutls_state_st * state = &state_server; | |
2320 | unsigned size; | |
2321 | uschar * buf; | |
059ec3d9 | 2322 | |
0d81dabc JH |
2323 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2324 | if (!tls_refill(*len)) | |
059ec3d9 | 2325 | { |
0d81dabc JH |
2326 | if (!state->xfer_error) return smtp_getbuf(len); |
2327 | *len = 0; | |
2328 | return NULL; | |
059ec3d9 | 2329 | } |
059ec3d9 | 2330 | |
0d81dabc JH |
2331 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
2332 | size = *len; | |
2333 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
2334 | state->xfer_buffer_lwm += size; | |
2335 | *len = size; | |
2336 | return buf; | |
059ec3d9 PH |
2337 | } |
2338 | ||
0d81dabc | 2339 | |
584e96c6 JH |
2340 | void |
2341 | tls_get_cache() | |
2342 | { | |
9960d1e5 | 2343 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2344 | exim_gnutls_state_st * state = &state_server; |
2345 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2346 | if (n > 0) | |
2347 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2348 | #endif |
9960d1e5 | 2349 | } |
584e96c6 | 2350 | |
059ec3d9 | 2351 | |
925ac8e4 JH |
2352 | BOOL |
2353 | tls_could_read(void) | |
2354 | { | |
2355 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
2356 | || gnutls_record_check_pending(state_server.session) > 0; | |
2357 | } | |
2358 | ||
2359 | ||
059ec3d9 | 2360 | |
17c76198 | 2361 | |
059ec3d9 PH |
2362 | /************************************************* |
2363 | * Read bytes from TLS channel * | |
2364 | *************************************************/ | |
2365 | ||
17c76198 PP |
2366 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2367 | then the caller must feed DKIM. | |
817d9f57 | 2368 | |
059ec3d9 PH |
2369 | Arguments: |
2370 | buff buffer of data | |
2371 | len size of buffer | |
2372 | ||
2373 | Returns: the number of bytes read | |
2374 | -1 after a failed read | |
2375 | */ | |
2376 | ||
2377 | int | |
817d9f57 | 2378 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2379 | { |
817d9f57 | 2380 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2381 | ssize_t inbytes; |
059ec3d9 | 2382 | |
17c76198 PP |
2383 | if (len > INT_MAX) |
2384 | len = INT_MAX; | |
059ec3d9 | 2385 | |
17c76198 PP |
2386 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2387 | DEBUG(D_tls) | |
2388 | debug_printf("*** PROBABLY A BUG *** " \ | |
2389 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2390 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2391 | ||
2392 | DEBUG(D_tls) | |
2393 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2394 | state->session, buff, len); | |
2395 | ||
2396 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2397 | if (inbytes > 0) return inbytes; |
2398 | if (inbytes == 0) | |
2399 | { | |
2400 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2401 | } | |
17c76198 | 2402 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2403 | |
2404 | return -1; | |
2405 | } | |
2406 | ||
2407 | ||
2408 | ||
17c76198 | 2409 | |
059ec3d9 PH |
2410 | /************************************************* |
2411 | * Write bytes down TLS channel * | |
2412 | *************************************************/ | |
2413 | ||
2414 | /* | |
2415 | Arguments: | |
817d9f57 | 2416 | is_server channel specifier |
059ec3d9 PH |
2417 | buff buffer of data |
2418 | len number of bytes | |
925ac8e4 | 2419 | more more data expected soon |
059ec3d9 PH |
2420 | |
2421 | Returns: the number of bytes after a successful write, | |
2422 | -1 after a failed write | |
2423 | */ | |
2424 | ||
2425 | int | |
925ac8e4 | 2426 | tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2427 | { |
17c76198 PP |
2428 | ssize_t outbytes; |
2429 | size_t left = len; | |
817d9f57 | 2430 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
925ac8e4 JH |
2431 | #ifdef SUPPORT_CORK |
2432 | static BOOL corked = FALSE; | |
2433 | ||
2434 | if (more && !corked) gnutls_record_cork(state->session); | |
2435 | #endif | |
2436 | ||
2437 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
2438 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 2439 | |
059ec3d9 PH |
2440 | while (left > 0) |
2441 | { | |
17c76198 PP |
2442 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2443 | buff, left); | |
2444 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2445 | |
17c76198 | 2446 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2447 | if (outbytes < 0) |
2448 | { | |
17c76198 | 2449 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2450 | return -1; |
2451 | } | |
2452 | if (outbytes == 0) | |
2453 | { | |
17c76198 | 2454 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2455 | return -1; |
2456 | } | |
2457 | ||
2458 | left -= outbytes; | |
2459 | buff += outbytes; | |
2460 | } | |
2461 | ||
17c76198 PP |
2462 | if (len > INT_MAX) |
2463 | { | |
2464 | DEBUG(D_tls) | |
2465 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2466 | len); | |
2467 | len = INT_MAX; | |
2468 | } | |
2469 | ||
925ac8e4 JH |
2470 | #ifdef SUPPORT_CORK |
2471 | if (more != corked) | |
2472 | { | |
2473 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
2474 | corked = more; | |
2475 | } | |
2476 | #endif | |
2477 | ||
17c76198 | 2478 | return (int) len; |
059ec3d9 PH |
2479 | } |
2480 | ||
2481 | ||
2482 | ||
17c76198 | 2483 | |
059ec3d9 | 2484 | /************************************************* |
17c76198 | 2485 | * Random number generation * |
059ec3d9 PH |
2486 | *************************************************/ |
2487 | ||
17c76198 PP |
2488 | /* Pseudo-random number generation. The result is not expected to be |
2489 | cryptographically strong but not so weak that someone will shoot themselves | |
2490 | in the foot using it as a nonce in input in some email header scheme or | |
2491 | whatever weirdness they'll twist this into. The result should handle fork() | |
2492 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2493 | |
17c76198 PP |
2494 | Arguments: |
2495 | max range maximum | |
2496 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2497 | */ |
2498 | ||
af3498d6 | 2499 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2500 | int |
2501 | vaguely_random_number(int max) | |
059ec3d9 | 2502 | { |
17c76198 PP |
2503 | unsigned int r; |
2504 | int i, needed_len; | |
2505 | uschar *p; | |
2506 | uschar smallbuf[sizeof(r)]; | |
2507 | ||
2508 | if (max <= 1) | |
2509 | return 0; | |
2510 | ||
2511 | needed_len = sizeof(r); | |
2512 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2513 | * asked for a number less than 10. */ | |
2514 | for (r = max, i = 0; r; ++i) | |
2515 | r >>= 1; | |
2516 | i = (i + 7) / 8; | |
2517 | if (i < needed_len) | |
2518 | needed_len = i; | |
2519 | ||
2520 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2521 | if (i < 0) | |
059ec3d9 | 2522 | { |
17c76198 PP |
2523 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2524 | return vaguely_random_number_fallback(max); | |
2525 | } | |
2526 | r = 0; | |
2527 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2528 | { | |
2529 | r *= 256; | |
2530 | r += *p; | |
059ec3d9 PH |
2531 | } |
2532 | ||
17c76198 PP |
2533 | /* We don't particularly care about weighted results; if someone wants |
2534 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2535 | return r % max; | |
059ec3d9 | 2536 | } |
af3498d6 PP |
2537 | #else /* HAVE_GNUTLS_RND */ |
2538 | int | |
2539 | vaguely_random_number(int max) | |
2540 | { | |
2541 | return vaguely_random_number_fallback(max); | |
2542 | } | |
2543 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2544 | |
36f12725 NM |
2545 | |
2546 | ||
2547 | ||
3375e053 PP |
2548 | /************************************************* |
2549 | * Let tls_require_ciphers be checked at startup * | |
2550 | *************************************************/ | |
2551 | ||
2552 | /* The tls_require_ciphers option, if set, must be something which the | |
2553 | library can parse. | |
2554 | ||
2555 | Returns: NULL on success, or error message | |
2556 | */ | |
2557 | ||
2558 | uschar * | |
2559 | tls_validate_require_cipher(void) | |
2560 | { | |
2561 | int rc; | |
2562 | uschar *expciphers = NULL; | |
2563 | gnutls_priority_t priority_cache; | |
2564 | const char *errpos; | |
cf0c6164 | 2565 | uschar * dummy_errstr; |
3375e053 PP |
2566 | |
2567 | #define validate_check_rc(Label) do { \ | |
2568 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2569 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2570 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2571 | ||
2572 | if (exim_gnutls_base_init_done) | |
2573 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2574 | "already initialised GnuTLS, Exim developer bug"); | |
2575 | ||
a5f239e4 | 2576 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2577 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2578 | { |
2579 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2580 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2581 | } | |
2582 | #endif | |
3375e053 PP |
2583 | rc = gnutls_global_init(); |
2584 | validate_check_rc(US"gnutls_global_init()"); | |
2585 | exim_gnutls_base_init_done = TRUE; | |
2586 | ||
2587 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2588 | return_deinit(NULL); | |
2589 | ||
cf0c6164 JH |
2590 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
2591 | &dummy_errstr)) | |
3375e053 PP |
2592 | return_deinit(US"failed to expand tls_require_ciphers"); |
2593 | ||
2594 | if (!(expciphers && *expciphers)) | |
2595 | return_deinit(NULL); | |
2596 | ||
2597 | DEBUG(D_tls) | |
2598 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2599 | ||
2600 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2601 | validate_check_rc(string_sprintf( | |
2602 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2603 | expciphers, errpos - CS expciphers, errpos)); | |
2604 | ||
2605 | #undef return_deinit | |
2606 | #undef validate_check_rc | |
2607 | gnutls_global_deinit(); | |
2608 | ||
2609 | return NULL; | |
2610 | } | |
2611 | ||
2612 | ||
2613 | ||
2614 | ||
36f12725 NM |
2615 | /************************************************* |
2616 | * Report the library versions. * | |
2617 | *************************************************/ | |
2618 | ||
2619 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2620 | ||
2621 | Arguments: a FILE* to print the results to | |
2622 | Returns: nothing | |
2623 | */ | |
2624 | ||
2625 | void | |
2626 | tls_version_report(FILE *f) | |
2627 | { | |
754a0503 PP |
2628 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2629 | " Runtime: %s\n", | |
2630 | LIBGNUTLS_VERSION, | |
2631 | gnutls_check_version(NULL)); | |
36f12725 NM |
2632 | } |
2633 | ||
2b4a568d JH |
2634 | /* vi: aw ai sw=2 |
2635 | */ | |
059ec3d9 | 2636 | /* End of tls-gnu.c */ |