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 | |
47195144 JH |
66 | #if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP) |
67 | # define SUPPORT_SRV_OCSP_STACK | |
68 | #endif | |
7e07527a | 69 | |
f2de3a33 | 70 | #ifndef DISABLE_OCSP |
2b4a568d JH |
71 | # include <gnutls/ocsp.h> |
72 | #endif | |
059ec3d9 | 73 | |
17c76198 | 74 | /* GnuTLS 2 vs 3 |
059ec3d9 | 75 | |
17c76198 PP |
76 | GnuTLS 3 only: |
77 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 78 | |
17c76198 PP |
79 | Changes: |
80 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
81 | */ | |
059ec3d9 | 82 | |
17c76198 | 83 | /* Local static variables for GnuTLS */ |
059ec3d9 | 84 | |
17c76198 | 85 | /* Values for verify_requirement */ |
059ec3d9 | 86 | |
e51c7be2 | 87 | enum peer_verify_requirement |
aa2a70ba | 88 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 89 | |
17c76198 PP |
90 | /* This holds most state for server or client; with this, we can set up an |
91 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
92 | over the TLS variables available for expansion. | |
059ec3d9 | 93 | |
17c76198 PP |
94 | Some of these correspond to variables in globals.c; those variables will |
95 | be set to point to content in one of these instances, as appropriate for | |
96 | the stage of the process lifetime. | |
059ec3d9 | 97 | |
389ca47a | 98 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 99 | */ |
059ec3d9 | 100 | |
17c76198 | 101 | typedef struct exim_gnutls_state { |
9d1c15ef | 102 | gnutls_session_t session; |
17c76198 | 103 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 104 | gnutls_priority_t priority_cache; |
17c76198 | 105 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
106 | int fd_in; |
107 | int fd_out; | |
108 | BOOL peer_cert_verified; | |
109 | BOOL trigger_sni_changes; | |
110 | BOOL have_set_peerdn; | |
17c76198 | 111 | const struct host_item *host; |
9d1c15ef JH |
112 | gnutls_x509_crt_t peercert; |
113 | uschar *peerdn; | |
114 | uschar *ciphersuite; | |
115 | uschar *received_sni; | |
17c76198 PP |
116 | |
117 | const uschar *tls_certificate; | |
118 | const uschar *tls_privatekey; | |
119 | const uschar *tls_sni; /* client send only, not received */ | |
120 | const uschar *tls_verify_certificates; | |
121 | const uschar *tls_crl; | |
122 | const uschar *tls_require_ciphers; | |
e51c7be2 | 123 | |
17c76198 PP |
124 | uschar *exp_tls_certificate; |
125 | uschar *exp_tls_privatekey; | |
17c76198 PP |
126 | uschar *exp_tls_verify_certificates; |
127 | uschar *exp_tls_crl; | |
128 | uschar *exp_tls_require_ciphers; | |
55414b25 | 129 | const uschar *exp_tls_verify_cert_hostnames; |
0cbf2b82 | 130 | #ifndef DISABLE_EVENT |
a7538db1 JH |
131 | uschar *event_action; |
132 | #endif | |
17c76198 | 133 | |
389ca47a | 134 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 135 | |
17c76198 PP |
136 | uschar *xfer_buffer; |
137 | int xfer_buffer_lwm; | |
138 | int xfer_buffer_hwm; | |
139 | int xfer_eof; | |
140 | int xfer_error; | |
17c76198 PP |
141 | } exim_gnutls_state_st; |
142 | ||
143 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
f2ed27cf JH |
144 | .session = NULL, |
145 | .x509_cred = NULL, | |
146 | .priority_cache = NULL, | |
147 | .verify_requirement = VERIFY_NONE, | |
148 | .fd_in = -1, | |
149 | .fd_out = -1, | |
150 | .peer_cert_verified = FALSE, | |
151 | .trigger_sni_changes =FALSE, | |
152 | .have_set_peerdn = FALSE, | |
153 | .host = NULL, | |
154 | .peercert = NULL, | |
155 | .peerdn = NULL, | |
156 | .ciphersuite = NULL, | |
157 | .received_sni = NULL, | |
158 | ||
159 | .tls_certificate = NULL, | |
160 | .tls_privatekey = NULL, | |
161 | .tls_sni = NULL, | |
162 | .tls_verify_certificates = NULL, | |
163 | .tls_crl = NULL, | |
164 | .tls_require_ciphers =NULL, | |
165 | ||
166 | .exp_tls_certificate = NULL, | |
167 | .exp_tls_privatekey = NULL, | |
168 | .exp_tls_verify_certificates = NULL, | |
169 | .exp_tls_crl = NULL, | |
170 | .exp_tls_require_ciphers = NULL, | |
f2ed27cf | 171 | .exp_tls_verify_cert_hostnames = NULL, |
0cbf2b82 | 172 | #ifndef DISABLE_EVENT |
f2ed27cf | 173 | .event_action = NULL, |
e51c7be2 | 174 | #endif |
f2ed27cf JH |
175 | .tlsp = NULL, |
176 | ||
177 | .xfer_buffer = NULL, | |
178 | .xfer_buffer_lwm = 0, | |
179 | .xfer_buffer_hwm = 0, | |
180 | .xfer_eof = 0, | |
181 | .xfer_error = 0, | |
17c76198 | 182 | }; |
83da1223 | 183 | |
17c76198 PP |
184 | /* Not only do we have our own APIs which don't pass around state, assuming |
185 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
186 | for callbacks, or as part of the session, so we have to keep a "this is the | |
187 | context we're currently dealing with" pointer and rely upon being | |
188 | single-threaded to keep from processing data on an inbound TLS connection while | |
189 | talking to another TLS connection for an outbound check. This does mean that | |
190 | there's no way for heart-beats to be responded to, for the duration of the | |
a7538db1 JH |
191 | second connection. |
192 | XXX But see gnutls_session_get_ptr() | |
193 | */ | |
059ec3d9 | 194 | |
17c76198 | 195 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 196 | |
17c76198 PP |
197 | /* dh_params are initialised once within the lifetime of a process using TLS; |
198 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
199 | don't want to repeat this. */ | |
83da1223 | 200 | |
17c76198 | 201 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 202 | |
17c76198 | 203 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 204 | |
17c76198 | 205 | static const int ssl_session_timeout = 200; |
059ec3d9 | 206 | |
17c76198 | 207 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 208 | |
17c76198 | 209 | /* Guard library core initialisation */ |
83da1223 | 210 | |
17c76198 | 211 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 212 | |
4fb7df6d | 213 | #ifndef DISABLE_OCSP |
9196d5bf | 214 | static BOOL gnutls_buggy_ocsp = FALSE; |
4fb7df6d | 215 | #endif |
9196d5bf | 216 | |
059ec3d9 | 217 | |
17c76198 PP |
218 | /* ------------------------------------------------------------------------ */ |
219 | /* macros */ | |
83da1223 | 220 | |
17c76198 | 221 | #define MAX_HOST_LEN 255 |
83da1223 | 222 | |
17c76198 PP |
223 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
224 | the library logging; a value less than 0 disables the calls to set up logging | |
ef9da2ee JH |
225 | callbacks. Possibly GNuTLS also looks for an environment variable |
226 | "GNUTLS_DEBUG_LEVEL". */ | |
2c17bb02 | 227 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
a7538db1 | 228 | # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 229 | #endif |
83da1223 | 230 | |
2c17bb02 | 231 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
a7538db1 | 232 | # define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 233 | #endif |
83da1223 | 234 | |
af3498d6 PP |
235 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
236 | can ask for a bit-strength. Without that, we stick to the constant we had | |
237 | before, for now. */ | |
2c17bb02 | 238 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
a7538db1 | 239 | # define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 240 | #endif |
af3498d6 | 241 | |
47195144 JH |
242 | #define exim_gnutls_err_check(rc, Label) do { \ |
243 | if ((rc) != GNUTLS_E_SUCCESS) \ | |
cf0c6164 JH |
244 | return tls_error((Label), gnutls_strerror(rc), host, errstr); \ |
245 | } while (0) | |
059ec3d9 | 246 | |
cf0c6164 JH |
247 | #define expand_check_tlsvar(Varname, errstr) \ |
248 | expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) | |
83da1223 | 249 | |
17c76198 | 250 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
251 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
252 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
253 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
254 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
255 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
256 | * isn't available sometimes, so this needs to become a conditional | |
257 | * compilation; the sanest way to deal with this being a problem on | |
258 | * older OSes is to block it in the Local/Makefile with this compiler | |
259 | * definition */ | |
e51c7be2 JH |
260 | # ifndef AVOID_GNUTLS_PKCS11 |
261 | # define HAVE_GNUTLS_PKCS11 | |
262 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 263 | #endif |
83da1223 | 264 | |
af3498d6 PP |
265 | |
266 | ||
267 | ||
268 | /* ------------------------------------------------------------------------ */ | |
269 | /* Callback declarations */ | |
270 | ||
271 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
272 | static void exim_gnutls_logger_cb(int level, const char *message); | |
273 | #endif | |
274 | ||
275 | static int exim_sni_handling_cb(gnutls_session_t session); | |
276 | ||
f2de3a33 | 277 | #ifndef DISABLE_OCSP |
44662487 JH |
278 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, |
279 | gnutls_datum_t * ocsp_response); | |
280 | #endif | |
af3498d6 PP |
281 | |
282 | ||
283 | ||
17c76198 PP |
284 | /* ------------------------------------------------------------------------ */ |
285 | /* Static functions */ | |
059ec3d9 PH |
286 | |
287 | /************************************************* | |
288 | * Handle TLS error * | |
289 | *************************************************/ | |
290 | ||
291 | /* Called from lots of places when errors occur before actually starting to do | |
292 | the TLS handshake, that is, while the session is still in clear. Always returns | |
293 | DEFER for a server and FAIL for a client so that most calls can use "return | |
294 | tls_error(...)" to do this processing and then give an appropriate return. A | |
295 | single function is used for both server and client, because it is called from | |
296 | some shared functions. | |
297 | ||
298 | Argument: | |
299 | prefix text to include in the logged error | |
7199e1ee TF |
300 | msg additional error string (may be NULL) |
301 | usually obtained from gnutls_strerror() | |
17c76198 PP |
302 | host NULL if setting up a server; |
303 | the connected host if setting up a client | |
cf0c6164 | 304 | errstr pointer to returned error string |
059ec3d9 PH |
305 | |
306 | Returns: OK/DEFER/FAIL | |
307 | */ | |
308 | ||
309 | static int | |
cf0c6164 JH |
310 | tls_error(const uschar *prefix, const char *msg, const host_item *host, |
311 | uschar ** errstr) | |
059ec3d9 | 312 | { |
cf0c6164 JH |
313 | if (errstr) |
314 | *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); | |
315 | return host ? FAIL : DEFER; | |
059ec3d9 PH |
316 | } |
317 | ||
318 | ||
319 | ||
17c76198 | 320 | |
059ec3d9 | 321 | /************************************************* |
17c76198 | 322 | * Deal with logging errors during I/O * |
059ec3d9 PH |
323 | *************************************************/ |
324 | ||
17c76198 | 325 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 326 | |
17c76198 PP |
327 | Argument: |
328 | state the current GnuTLS exim state container | |
329 | rc the GnuTLS error code, or 0 if it's a local error | |
330 | when text identifying read or write | |
331 | text local error text when ec is 0 | |
059ec3d9 | 332 | |
17c76198 | 333 | Returns: nothing |
059ec3d9 PH |
334 | */ |
335 | ||
17c76198 PP |
336 | static void |
337 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 338 | { |
cf0c6164 JH |
339 | const char * msg; |
340 | uschar * errstr; | |
059ec3d9 | 341 | |
17c76198 PP |
342 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
343 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
344 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
345 | else | |
346 | msg = gnutls_strerror(rc); | |
059ec3d9 | 347 | |
cf0c6164 JH |
348 | (void) tls_error(when, msg, state->host, &errstr); |
349 | ||
350 | if (state->host) | |
351 | log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", | |
352 | state->host->name, state->host->address, errstr); | |
353 | else | |
354 | { | |
355 | uschar * conn_info = smtp_get_connection_info(); | |
356 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; | |
357 | /* I'd like to get separated H= here, but too hard for now */ | |
358 | log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); | |
359 | } | |
17c76198 | 360 | } |
059ec3d9 | 361 | |
059ec3d9 | 362 | |
059ec3d9 | 363 | |
059ec3d9 | 364 | |
17c76198 PP |
365 | /************************************************* |
366 | * Set various Exim expansion vars * | |
367 | *************************************************/ | |
059ec3d9 | 368 | |
e51c7be2 JH |
369 | #define exim_gnutls_cert_err(Label) \ |
370 | do \ | |
371 | { \ | |
372 | if (rc != GNUTLS_E_SUCCESS) \ | |
373 | { \ | |
374 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
375 | (Label), gnutls_strerror(rc)); \ | |
376 | return rc; \ | |
377 | } \ | |
378 | } while (0) | |
9d1c15ef JH |
379 | |
380 | static int | |
27f19eb4 | 381 | import_cert(const gnutls_datum_t * cert, gnutls_x509_crt_t * crtp) |
9d1c15ef JH |
382 | { |
383 | int rc; | |
384 | ||
385 | rc = gnutls_x509_crt_init(crtp); | |
386 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
387 | ||
388 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
389 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
390 | ||
391 | return rc; | |
392 | } | |
393 | ||
394 | #undef exim_gnutls_cert_err | |
395 | ||
396 | ||
17c76198 PP |
397 | /* We set various Exim global variables from the state, once a session has |
398 | been established. With TLS callouts, may need to change this to stack | |
399 | variables, or just re-call it with the server state after client callout | |
400 | has finished. | |
059ec3d9 | 401 | |
9d1c15ef | 402 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
403 | |
404 | Sets: | |
405 | tls_active fd | |
406 | tls_bits strength indicator | |
407 | tls_certificate_verified bool indicator | |
408 | tls_channelbinding_b64 for some SASL mechanisms | |
409 | tls_cipher a string | |
9d1c15ef | 410 | tls_peercert pointer to library internal |
17c76198 PP |
411 | tls_peerdn a string |
412 | tls_sni a (UTF-8) string | |
9d1c15ef | 413 | tls_ourcert pointer to library internal |
17c76198 PP |
414 | |
415 | Argument: | |
416 | state the relevant exim_gnutls_state_st * | |
417 | */ | |
418 | ||
419 | static void | |
9d1c15ef | 420 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 421 | { |
17c76198 | 422 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
423 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
424 | int old_pool; | |
425 | int rc; | |
426 | gnutls_datum_t channel; | |
427 | #endif | |
9d1c15ef | 428 | tls_support * tlsp = state->tlsp; |
17c76198 | 429 | |
9d1c15ef | 430 | tlsp->active = state->fd_out; |
17c76198 PP |
431 | |
432 | cipher = gnutls_cipher_get(state->session); | |
433 | /* returns size in "bytes" */ | |
9d1c15ef | 434 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 435 | |
9d1c15ef | 436 | tlsp->cipher = state->ciphersuite; |
17c76198 | 437 | |
817d9f57 | 438 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 439 | |
9d1c15ef | 440 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 441 | |
17c76198 PP |
442 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
443 | only available for use for authenticators while this TLS session is running. */ | |
444 | ||
445 | tls_channelbinding_b64 = NULL; | |
446 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
447 | channel.data = NULL; | |
448 | channel.size = 0; | |
449 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
450 | if (rc) { | |
451 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
452 | } else { | |
453 | old_pool = store_pool; | |
454 | store_pool = POOL_PERM; | |
f4d091fb | 455 | tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); |
17c76198 PP |
456 | store_pool = old_pool; |
457 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
458 | } | |
459 | #endif | |
460 | ||
9d1c15ef JH |
461 | /* peercert is set in peer_status() */ |
462 | tlsp->peerdn = state->peerdn; | |
463 | tlsp->sni = state->received_sni; | |
464 | ||
465 | /* record our certificate */ | |
466 | { | |
27f19eb4 | 467 | const gnutls_datum_t * cert = gnutls_certificate_get_ours(state->session); |
9d1c15ef JH |
468 | gnutls_x509_crt_t crt; |
469 | ||
470 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
471 | } | |
059ec3d9 PH |
472 | } |
473 | ||
474 | ||
475 | ||
17c76198 | 476 | |
059ec3d9 | 477 | /************************************************* |
575643cd | 478 | * Setup up DH parameters * |
059ec3d9 PH |
479 | *************************************************/ |
480 | ||
575643cd | 481 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
482 | be re-generated every so often, depending on security policy. What we do is to |
483 | keep these parameters in a file in the spool directory. If the file does not | |
484 | exist, we generate them. This means that it is easy to cause a regeneration. | |
485 | ||
486 | The new file is written as a temporary file and renamed, so that an incomplete | |
487 | file is never present. If two processes both compute some new parameters, you | |
488 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
489 | prevent this. | |
490 | ||
059ec3d9 PH |
491 | Returns: OK/DEFER/FAIL |
492 | */ | |
493 | ||
494 | static int | |
cf0c6164 | 495 | init_server_dh(uschar ** errstr) |
059ec3d9 | 496 | { |
17c76198 PP |
497 | int fd, rc; |
498 | unsigned int dh_bits; | |
27f19eb4 | 499 | gnutls_datum_t m; |
a799883d PP |
500 | uschar filename_buf[PATH_MAX]; |
501 | uschar *filename = NULL; | |
17c76198 | 502 | size_t sz; |
a799883d PP |
503 | uschar *exp_tls_dhparam; |
504 | BOOL use_file_in_spool = FALSE; | |
505 | BOOL use_fixed_file = FALSE; | |
17c76198 | 506 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 507 | |
17c76198 | 508 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 509 | |
17c76198 | 510 | rc = gnutls_dh_params_init(&dh_server_params); |
47195144 | 511 | exim_gnutls_err_check(rc, US"gnutls_dh_params_init"); |
059ec3d9 | 512 | |
a799883d PP |
513 | m.data = NULL; |
514 | m.size = 0; | |
515 | ||
cf0c6164 | 516 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) |
a799883d PP |
517 | return DEFER; |
518 | ||
519 | if (!exp_tls_dhparam) | |
520 | { | |
521 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
522 | m.data = US std_dh_prime_default(); | |
523 | m.size = Ustrlen(m.data); | |
524 | } | |
525 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
526 | use_file_in_spool = TRUE; | |
527 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
528 | { | |
529 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
530 | return OK; | |
531 | } | |
532 | else if (exp_tls_dhparam[0] != '/') | |
533 | { | |
f5d25c2b | 534 | if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) |
cf0c6164 | 535 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); |
a799883d PP |
536 | m.size = Ustrlen(m.data); |
537 | } | |
538 | else | |
539 | { | |
540 | use_fixed_file = TRUE; | |
541 | filename = exp_tls_dhparam; | |
542 | } | |
543 | ||
544 | if (m.data) | |
545 | { | |
546 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
47195144 | 547 | exim_gnutls_err_check(rc, US"gnutls_dh_params_import_pkcs3"); |
a799883d PP |
548 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); |
549 | return OK; | |
550 | } | |
551 | ||
af3498d6 PP |
552 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
553 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
554 | different filename and ensure we have sufficient bits. */ |
555 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
556 | if (!dh_bits) | |
cf0c6164 | 557 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); |
af3498d6 | 558 | DEBUG(D_tls) |
b34fc30c | 559 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
560 | dh_bits); |
561 | #else | |
562 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
563 | DEBUG(D_tls) | |
564 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
565 | dh_bits); | |
566 | #endif | |
059ec3d9 | 567 | |
3375e053 PP |
568 | /* Some clients have hard-coded limits. */ |
569 | if (dh_bits > tls_dh_max_bits) | |
570 | { | |
571 | DEBUG(D_tls) | |
572 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
573 | tls_dh_max_bits); | |
574 | dh_bits = tls_dh_max_bits; | |
575 | } | |
576 | ||
a799883d PP |
577 | if (use_file_in_spool) |
578 | { | |
579 | if (!string_format(filename_buf, sizeof(filename_buf), | |
580 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
cf0c6164 | 581 | return tls_error(US"overlong filename", NULL, NULL, errstr); |
a799883d PP |
582 | filename = filename_buf; |
583 | } | |
059ec3d9 | 584 | |
b5aea5e1 | 585 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 586 | parameters. */ |
059ec3d9 | 587 | |
f5d25c2b | 588 | if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) |
059ec3d9 | 589 | { |
b5aea5e1 | 590 | struct stat statbuf; |
17c76198 PP |
591 | FILE *fp; |
592 | int saved_errno; | |
593 | ||
594 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
595 | { | |
596 | saved_errno = errno; | |
597 | (void)close(fd); | |
cf0c6164 | 598 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
599 | } |
600 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
601 | { |
602 | (void)close(fd); | |
cf0c6164 | 603 | return tls_error(US"TLS cache not a file", NULL, NULL, errstr); |
17c76198 | 604 | } |
40c90bca | 605 | if (!(fp = fdopen(fd, "rb"))) |
17c76198 PP |
606 | { |
607 | saved_errno = errno; | |
608 | (void)close(fd); | |
609 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
cf0c6164 | 610 | strerror(saved_errno), NULL, errstr); |
b5aea5e1 | 611 | } |
059ec3d9 | 612 | |
b5aea5e1 | 613 | m.size = statbuf.st_size; |
40c90bca | 614 | if (!(m.data = malloc(m.size))) |
17c76198 PP |
615 | { |
616 | fclose(fp); | |
cf0c6164 | 617 | return tls_error(US"malloc failed", strerror(errno), NULL, errstr); |
17c76198 | 618 | } |
40c90bca | 619 | if (!(sz = fread(m.data, m.size, 1, fp))) |
17c76198 PP |
620 | { |
621 | saved_errno = errno; | |
622 | fclose(fp); | |
623 | free(m.data); | |
cf0c6164 | 624 | return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); |
17c76198 PP |
625 | } |
626 | fclose(fp); | |
b5aea5e1 | 627 | |
17c76198 | 628 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 629 | free(m.data); |
47195144 | 630 | exim_gnutls_err_check(rc, US"gnutls_dh_params_import_pkcs3"); |
17c76198 | 631 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); |
b5aea5e1 PH |
632 | } |
633 | ||
634 | /* If the file does not exist, fall through to compute new data and cache it. | |
635 | If there was any other opening error, it is serious. */ | |
636 | ||
182ad5cf PH |
637 | else if (errno == ENOENT) |
638 | { | |
17c76198 | 639 | rc = -1; |
182ad5cf | 640 | DEBUG(D_tls) |
17c76198 | 641 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
642 | } |
643 | else | |
17c76198 | 644 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
cf0c6164 | 645 | NULL, NULL, errstr); |
b5aea5e1 PH |
646 | |
647 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
648 | is not useful. One particular case of this is when upgrading from an older | |
649 | release of Exim in which the data was stored in a different format. We don't | |
650 | try to be clever and support both formats; we just regenerate new data in this | |
651 | case. */ | |
652 | ||
17c76198 | 653 | if (rc < 0) |
b5aea5e1 | 654 | { |
17c76198 | 655 | uschar *temp_fn; |
201f5254 | 656 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 657 | |
17c76198 PP |
658 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
659 | return tls_error(US"Filename too long to generate replacement", | |
cf0c6164 | 660 | CS filename, NULL, errstr); |
059ec3d9 | 661 | |
17c76198 | 662 | temp_fn = string_copy(US "%s.XXXXXXX"); |
f5d25c2b | 663 | if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ |
cf0c6164 | 664 | return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); |
059ec3d9 PH |
665 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
666 | ||
201f5254 PP |
667 | /* GnuTLS overshoots! |
668 | * If we ask for 2236, we might get 2237 or more. | |
669 | * But there's no way to ask GnuTLS how many bits there really are. | |
670 | * We can ask how many bits were used in a TLS session, but that's it! | |
671 | * The prime itself is hidden behind too much abstraction. | |
672 | * So we ask for less, and proceed on a wing and a prayer. | |
673 | * First attempt, subtracted 3 for 2233 and got 2240. | |
674 | */ | |
cae6e576 | 675 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
676 | { |
677 | dh_bits_gen = dh_bits - 10; | |
678 | DEBUG(D_tls) | |
679 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
680 | dh_bits_gen); | |
681 | } | |
682 | ||
683 | DEBUG(D_tls) | |
684 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
685 | dh_bits_gen); | |
686 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
47195144 | 687 | exim_gnutls_err_check(rc, US"gnutls_dh_params_generate2"); |
17c76198 PP |
688 | |
689 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
690 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
691 | sample apps handle this. */ | |
692 | ||
693 | sz = 0; | |
694 | m.data = NULL; | |
695 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
696 | m.data, &sz); | |
697 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
47195144 | 698 | exim_gnutls_err_check(rc, US"gnutls_dh_params_export_pkcs3(NULL) sizing"); |
17c76198 | 699 | m.size = sz; |
40c90bca | 700 | if (!(m.data = malloc(m.size))) |
cf0c6164 | 701 | return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); |
40c90bca | 702 | |
1f00591e | 703 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 704 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 705 | m.data, &sz); |
17c76198 PP |
706 | if (rc != GNUTLS_E_SUCCESS) |
707 | { | |
708 | free(m.data); | |
47195144 | 709 | exim_gnutls_err_check(rc, US"gnutls_dh_params_export_pkcs3() real"); |
17c76198 | 710 | } |
1f00591e | 711 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 712 | |
f5d25c2b | 713 | if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) |
17c76198 PP |
714 | { |
715 | free(m.data); | |
716 | return tls_error(US"TLS cache write D-H params failed", | |
cf0c6164 | 717 | strerror(errno), NULL, errstr); |
17c76198 | 718 | } |
b5aea5e1 | 719 | free(m.data); |
f5d25c2b | 720 | if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) |
17c76198 | 721 | return tls_error(US"TLS cache write D-H params final newline failed", |
cf0c6164 | 722 | strerror(errno), NULL, errstr); |
17c76198 | 723 | |
f5d25c2b | 724 | if ((rc = close(fd))) |
cf0c6164 | 725 | return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); |
059ec3d9 | 726 | |
17c76198 PP |
727 | if (Urename(temp_fn, filename) < 0) |
728 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
cf0c6164 | 729 | temp_fn, filename), strerror(errno), NULL, errstr); |
059ec3d9 | 730 | |
17c76198 | 731 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
732 | } |
733 | ||
17c76198 | 734 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
735 | return OK; |
736 | } | |
737 | ||
738 | ||
739 | ||
740 | ||
23bb6982 JH |
741 | /* Create and install a selfsigned certificate, for use in server mode */ |
742 | ||
743 | static int | |
cf0c6164 | 744 | tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) |
23bb6982 JH |
745 | { |
746 | gnutls_x509_crt_t cert = NULL; | |
747 | time_t now; | |
748 | gnutls_x509_privkey_t pkey = NULL; | |
749 | const uschar * where; | |
750 | int rc; | |
751 | ||
752 | where = US"initialising pkey"; | |
753 | if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; | |
754 | ||
755 | where = US"initialising cert"; | |
756 | if ((rc = gnutls_x509_crt_init(&cert))) goto err; | |
757 | ||
758 | where = US"generating pkey"; | |
759 | if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, | |
76075bb5 | 760 | #ifdef SUPPORT_PARAM_TO_PK_BITS |
23bb6982 | 761 | gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), |
76075bb5 JH |
762 | #else |
763 | 1024, | |
764 | #endif | |
765 | 0))) | |
23bb6982 JH |
766 | goto err; |
767 | ||
768 | where = US"configuring cert"; | |
769 | now = 0; | |
770 | if ( (rc = gnutls_x509_crt_set_version(cert, 3)) | |
771 | || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) | |
772 | || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) | |
773 | || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ | |
774 | || (rc = gnutls_x509_crt_set_key(cert, pkey)) | |
775 | ||
776 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
777 | GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) | |
778 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
779 | GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) | |
780 | || (rc = gnutls_x509_crt_set_dn_by_oid(cert, | |
781 | GNUTLS_OID_X520_COMMON_NAME, 0, | |
782 | smtp_active_hostname, Ustrlen(smtp_active_hostname))) | |
783 | ) | |
784 | goto err; | |
785 | ||
786 | where = US"signing cert"; | |
787 | if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; | |
788 | ||
789 | where = US"installing selfsign cert"; | |
790 | /* Since: 2.4.0 */ | |
791 | if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) | |
792 | goto err; | |
793 | ||
794 | rc = OK; | |
795 | ||
796 | out: | |
797 | if (cert) gnutls_x509_crt_deinit(cert); | |
798 | if (pkey) gnutls_x509_privkey_deinit(pkey); | |
799 | return rc; | |
800 | ||
801 | err: | |
cf0c6164 | 802 | rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); |
23bb6982 JH |
803 | goto out; |
804 | } | |
805 | ||
806 | ||
807 | ||
808 | ||
47195144 JH |
809 | /* Add certificate and key, from files. |
810 | ||
811 | Return: | |
812 | Zero or negative: good. Negate value for certificate index if < 0. | |
813 | Greater than zero: FAIL or DEFER code. | |
814 | */ | |
815 | ||
ba86e143 JH |
816 | static int |
817 | tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, | |
818 | uschar * certfile, uschar * keyfile, uschar ** errstr) | |
819 | { | |
820 | int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, | |
821 | CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); | |
47195144 JH |
822 | if (rc < 0) |
823 | return tls_error( | |
824 | string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile), | |
825 | gnutls_strerror(rc), host, errstr); | |
826 | return -rc; | |
ba86e143 JH |
827 | } |
828 | ||
829 | ||
059ec3d9 | 830 | /************************************************* |
17c76198 | 831 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
832 | *************************************************/ |
833 | ||
17c76198 PP |
834 | /* Called from both server and client code, via tls_init(), and also from |
835 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
836 | ||
837 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
838 | ||
839 | The callback should not call us unless state->trigger_sni_changes is true, | |
840 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
841 | |
842 | Arguments: | |
17c76198 | 843 | state exim_gnutls_state_st * |
cf0c6164 | 844 | errstr error string pointer |
059ec3d9 PH |
845 | |
846 | Returns: OK/DEFER/FAIL | |
847 | */ | |
848 | ||
849 | static int | |
ba86e143 | 850 | tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr) |
059ec3d9 | 851 | { |
1365611d | 852 | struct stat statbuf; |
059ec3d9 | 853 | int rc; |
17c76198 PP |
854 | const host_item *host = state->host; /* macro should be reconsidered? */ |
855 | uschar *saved_tls_certificate = NULL; | |
856 | uschar *saved_tls_privatekey = NULL; | |
857 | uschar *saved_tls_verify_certificates = NULL; | |
858 | uschar *saved_tls_crl = NULL; | |
859 | int cert_count; | |
860 | ||
861 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 862 | if (!host) /* server */ |
17c76198 PP |
863 | if (!state->received_sni) |
864 | { | |
ba86e143 JH |
865 | if ( state->tls_certificate |
866 | && ( Ustrstr(state->tls_certificate, US"tls_sni") | |
867 | || Ustrstr(state->tls_certificate, US"tls_in_sni") | |
868 | || Ustrstr(state->tls_certificate, US"tls_out_sni") | |
869 | ) ) | |
17c76198 PP |
870 | { |
871 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
872 | state->trigger_sni_changes = TRUE; | |
873 | } | |
874 | } | |
875 | else | |
876 | { | |
1365611d | 877 | /* useful for debugging */ |
17c76198 PP |
878 | saved_tls_certificate = state->exp_tls_certificate; |
879 | saved_tls_privatekey = state->exp_tls_privatekey; | |
880 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
881 | saved_tls_crl = state->exp_tls_crl; | |
882 | } | |
059ec3d9 | 883 | |
1365611d | 884 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
47195144 JH |
885 | exim_gnutls_err_check(rc, US"gnutls_certificate_allocate_credentials"); |
886 | ||
887 | #ifdef SUPPORT_SRV_OCSP_STACK | |
888 | gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2); | |
889 | #endif | |
1365611d | 890 | |
17c76198 PP |
891 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
892 | state members, assuming consistent naming; and expand_check() returns | |
893 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 894 | |
17c76198 PP |
895 | /* check if we at least have a certificate, before doing expensive |
896 | D-H generation. */ | |
059ec3d9 | 897 | |
cf0c6164 | 898 | if (!expand_check_tlsvar(tls_certificate, errstr)) |
17c76198 | 899 | return DEFER; |
059ec3d9 | 900 | |
17c76198 | 901 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 902 | |
23bb6982 JH |
903 | if ( !state->exp_tls_certificate |
904 | || !*state->exp_tls_certificate | |
905 | ) | |
2b4a568d | 906 | if (!host) |
cf0c6164 | 907 | return tls_install_selfsign(state, errstr); |
17c76198 PP |
908 | else |
909 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
059ec3d9 | 910 | |
cf0c6164 | 911 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) |
059ec3d9 PH |
912 | return DEFER; |
913 | ||
17c76198 PP |
914 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
915 | ||
916 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 917 | { |
17c76198 PP |
918 | state->tls_privatekey = state->tls_certificate; |
919 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 920 | } |
c91535f3 | 921 | |
059ec3d9 | 922 | |
17c76198 | 923 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
924 | { |
925 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
926 | state->exp_tls_certificate, state->exp_tls_privatekey); |
927 | ||
928 | if (state->received_sni) | |
23bb6982 JH |
929 | if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 |
930 | && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 | |
931 | ) | |
17c76198 | 932 | { |
b34fc30c | 933 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
934 | } |
935 | else | |
936 | { | |
b34fc30c | 937 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 938 | } |
059ec3d9 | 939 | |
ba86e143 JH |
940 | if (!host) /* server */ |
941 | { | |
942 | const uschar * clist = state->exp_tls_certificate; | |
943 | const uschar * klist = state->exp_tls_privatekey; | |
47195144 JH |
944 | const uschar * olist; |
945 | int csep = 0, ksep = 0, osep = 0, cnt = 0; | |
946 | uschar * cfile, * kfile, * ofile; | |
947 | ||
948 | #ifndef DISABLE_OCSP | |
949 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr)) | |
950 | return DEFER; | |
951 | olist = ofile; | |
952 | #endif | |
ba86e143 JH |
953 | |
954 | while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) | |
47195144 | 955 | |
ba86e143 JH |
956 | if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) |
957 | return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); | |
47195144 | 958 | else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr))) |
ba86e143 JH |
959 | return rc; |
960 | else | |
47195144 JH |
961 | { |
962 | int gnutls_cert_index = -rc; | |
ba86e143 | 963 | DEBUG(D_tls) debug_printf("TLS: cert/key %s registered\n", cfile); |
47195144 JH |
964 | |
965 | /* Set the OCSP stapling server info */ | |
966 | ||
967 | #ifndef DISABLE_OCSP | |
968 | if (tls_ocsp_file) | |
969 | if (gnutls_buggy_ocsp) | |
970 | { | |
971 | DEBUG(D_tls) | |
972 | debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); | |
973 | } | |
974 | else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) | |
975 | { | |
976 | /* Use the full callback method for stapling just to get | |
977 | observability. More efficient would be to read the file once only, | |
978 | if it never changed (due to SNI). Would need restart on file update, | |
979 | or watch datestamp. */ | |
980 | ||
981 | # ifdef SUPPORT_SRV_OCSP_STACK | |
982 | rc = gnutls_certificate_set_ocsp_status_request_function2( | |
983 | state->x509_cred, gnutls_cert_index, | |
984 | server_ocsp_stapling_cb, ofile); | |
985 | ||
986 | exim_gnutls_err_check(rc, | |
987 | US"gnutls_certificate_set_ocsp_status_request_function2"); | |
988 | # else | |
989 | if (cnt++ > 0) | |
990 | { | |
991 | DEBUG(D_tls) | |
992 | debug_printf("oops; multiple OCSP files not supported\n"); | |
993 | break; | |
994 | } | |
995 | gnutls_certificate_set_ocsp_status_request_function( | |
996 | state->x509_cred, server_ocsp_stapling_cb, ofile); | |
997 | # endif | |
998 | ||
999 | DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); | |
1000 | } | |
1001 | else | |
1002 | DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); | |
1003 | #endif | |
1004 | } | |
ba86e143 JH |
1005 | } |
1006 | else | |
1007 | { | |
47195144 | 1008 | if (0 < (rc = tls_add_certfile(state, host, |
ba86e143 JH |
1009 | state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) |
1010 | return rc; | |
1011 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
1012 | } | |
1013 | ||
b34fc30c | 1014 | } /* tls_certificate */ |
059ec3d9 | 1015 | |
2b4a568d | 1016 | |
059ec3d9 PH |
1017 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
1018 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
1019 | error message is provided. However, if we just refrain from setting anything up | |
1020 | in that case, certificate verification fails, which seems to be the correct | |
1021 | behaviour. */ | |
1022 | ||
610ff438 | 1023 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 1024 | { |
cf0c6164 | 1025 | if (!expand_check_tlsvar(tls_verify_certificates, errstr)) |
059ec3d9 | 1026 | return DEFER; |
610ff438 JH |
1027 | #ifndef SUPPORT_SYSDEFAULT_CABUNDLE |
1028 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1029 | state->exp_tls_verify_certificates = NULL; | |
1030 | #endif | |
17c76198 | 1031 | if (state->tls_crl && *state->tls_crl) |
cf0c6164 | 1032 | if (!expand_check_tlsvar(tls_crl, errstr)) |
17c76198 | 1033 | return DEFER; |
059ec3d9 | 1034 | |
1365611d PP |
1035 | if (!(state->exp_tls_verify_certificates && |
1036 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
1037 | { |
1038 | DEBUG(D_tls) | |
1365611d PP |
1039 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
1040 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 1041 | return OK; |
b34fc30c | 1042 | } |
1365611d | 1043 | } |
83e2f8a2 PP |
1044 | else |
1045 | { | |
1046 | DEBUG(D_tls) | |
1047 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
1048 | return OK; | |
1049 | } | |
17c76198 | 1050 | |
cb1d7830 JH |
1051 | #ifdef SUPPORT_SYSDEFAULT_CABUNDLE |
1052 | if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) | |
1053 | cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); | |
1054 | else | |
1055 | #endif | |
1365611d | 1056 | { |
cb1d7830 JH |
1057 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
1058 | { | |
1059 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
1060 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
1061 | strerror(errno)); | |
1062 | return DEFER; | |
1063 | } | |
17c76198 | 1064 | |
a7fec7a7 | 1065 | #ifndef SUPPORT_CA_DIR |
cb1d7830 JH |
1066 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
1067 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
1068 | other weirdness. The thing we really want to check is that it's not a | |
1069 | directory, since while OpenSSL supports that, GnuTLS does not. | |
60f914bc | 1070 | So s/!S_ISREG/S_ISDIR/ and change some messaging ... */ |
cb1d7830 JH |
1071 | if (S_ISDIR(statbuf.st_mode)) |
1072 | { | |
1073 | DEBUG(D_tls) | |
1074 | debug_printf("verify certificates path is a dir: \"%s\"\n", | |
1075 | state->exp_tls_verify_certificates); | |
1076 | log_write(0, LOG_MAIN|LOG_PANIC, | |
1077 | "tls_verify_certificates \"%s\" is a directory", | |
1078 | state->exp_tls_verify_certificates); | |
1079 | return DEFER; | |
1080 | } | |
a7fec7a7 | 1081 | #endif |
059ec3d9 | 1082 | |
cb1d7830 JH |
1083 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
1084 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 1085 | |
cb1d7830 JH |
1086 | if (statbuf.st_size == 0) |
1087 | { | |
1088 | DEBUG(D_tls) | |
1089 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
1090 | return OK; | |
1091 | } | |
059ec3d9 | 1092 | |
cb1d7830 | 1093 | cert_count = |
a7fec7a7 JH |
1094 | |
1095 | #ifdef SUPPORT_CA_DIR | |
cb1d7830 JH |
1096 | (statbuf.st_mode & S_IFMT) == S_IFDIR |
1097 | ? | |
1098 | gnutls_certificate_set_x509_trust_dir(state->x509_cred, | |
1099 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) | |
1100 | : | |
a7fec7a7 | 1101 | #endif |
cb1d7830 JH |
1102 | gnutls_certificate_set_x509_trust_file(state->x509_cred, |
1103 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
1104 | } | |
a7fec7a7 | 1105 | |
1365611d PP |
1106 | if (cert_count < 0) |
1107 | { | |
1108 | rc = cert_count; | |
47195144 | 1109 | exim_gnutls_err_check(rc, US"setting certificate trust"); |
1365611d PP |
1110 | } |
1111 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 1112 | |
5c8cda3a PP |
1113 | if (state->tls_crl && *state->tls_crl && |
1114 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 1115 | { |
5c8cda3a PP |
1116 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
1117 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
1118 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
1119 | if (cert_count < 0) | |
1365611d | 1120 | { |
5c8cda3a | 1121 | rc = cert_count; |
47195144 | 1122 | exim_gnutls_err_check(rc, US"gnutls_certificate_set_x509_crl_file"); |
1365611d | 1123 | } |
5c8cda3a | 1124 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 1125 | } |
059ec3d9 | 1126 | |
059ec3d9 PH |
1127 | return OK; |
1128 | } | |
1129 | ||
1130 | ||
1131 | ||
1132 | ||
1365611d PP |
1133 | /************************************************* |
1134 | * Set X.509 state variables * | |
1135 | *************************************************/ | |
1136 | ||
1137 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
1138 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
1139 | structure. Which means various other non-re-expanded pieces of state | |
1140 | need to be re-set in the new struct, so the setting logic is pulled | |
1141 | out to this. | |
1142 | ||
1143 | Arguments: | |
1144 | state exim_gnutls_state_st * | |
cf0c6164 | 1145 | errstr error string pointer |
1365611d PP |
1146 | |
1147 | Returns: OK/DEFER/FAIL | |
1148 | */ | |
1149 | ||
1150 | static int | |
cf0c6164 | 1151 | tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) |
1365611d PP |
1152 | { |
1153 | int rc; | |
1154 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
1155 | ||
1156 | /* Create D-H parameters, or read them from the cache file. This function does | |
1157 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
1158 | client-side params. */ | |
1159 | ||
1160 | if (!state->host) | |
1161 | { | |
1162 | if (!dh_server_params) | |
1163 | { | |
cf0c6164 | 1164 | rc = init_server_dh(errstr); |
1365611d PP |
1165 | if (rc != OK) return rc; |
1166 | } | |
1167 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
1168 | } | |
1169 | ||
1170 | /* Link the credentials to the session. */ | |
1171 | ||
1172 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
47195144 | 1173 | exim_gnutls_err_check(rc, US"gnutls_credentials_set"); |
1365611d PP |
1174 | |
1175 | return OK; | |
1176 | } | |
1177 | ||
059ec3d9 | 1178 | /************************************************* |
17c76198 | 1179 | * Initialize for GnuTLS * |
059ec3d9 PH |
1180 | *************************************************/ |
1181 | ||
9196d5bf | 1182 | |
4fb7df6d JH |
1183 | #ifndef DISABLE_OCSP |
1184 | ||
9196d5bf JH |
1185 | static BOOL |
1186 | tls_is_buggy_ocsp(void) | |
1187 | { | |
1188 | const uschar * s; | |
1189 | uschar maj, mid, mic; | |
1190 | ||
1191 | s = CUS gnutls_check_version(NULL); | |
1192 | maj = atoi(CCS s); | |
1193 | if (maj == 3) | |
1194 | { | |
1195 | while (*s && *s != '.') s++; | |
1196 | mid = atoi(CCS ++s); | |
1197 | if (mid <= 2) | |
1198 | return TRUE; | |
1199 | else if (mid >= 5) | |
1200 | return FALSE; | |
1201 | else | |
1202 | { | |
1203 | while (*s && *s != '.') s++; | |
1204 | mic = atoi(CCS ++s); | |
1205 | return mic <= (mid == 3 ? 16 : 3); | |
1206 | } | |
1207 | } | |
1208 | return FALSE; | |
1209 | } | |
1210 | ||
4fb7df6d | 1211 | #endif |
9196d5bf JH |
1212 | |
1213 | ||
17c76198 PP |
1214 | /* Called from both server and client code. In the case of a server, errors |
1215 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
1216 | |
1217 | Arguments: | |
17c76198 PP |
1218 | host connected host, if client; NULL if server |
1219 | certificate certificate file | |
1220 | privatekey private key file | |
1221 | sni TLS SNI to send, sometimes when client; else NULL | |
1222 | cas CA certs file | |
1223 | crl CRL file | |
1224 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 1225 | caller_state returned state-info structure |
cf0c6164 | 1226 | errstr error string pointer |
059ec3d9 | 1227 | |
17c76198 | 1228 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1229 | */ |
1230 | ||
17c76198 PP |
1231 | static int |
1232 | tls_init( | |
1233 | const host_item *host, | |
1234 | const uschar *certificate, | |
1235 | const uschar *privatekey, | |
1236 | const uschar *sni, | |
1237 | const uschar *cas, | |
1238 | const uschar *crl, | |
1239 | const uschar *require_ciphers, | |
cf0c6164 JH |
1240 | exim_gnutls_state_st **caller_state, |
1241 | uschar ** errstr) | |
059ec3d9 | 1242 | { |
17c76198 PP |
1243 | exim_gnutls_state_st *state; |
1244 | int rc; | |
1245 | size_t sz; | |
1246 | const char *errpos; | |
1247 | uschar *p; | |
1248 | BOOL want_default_priorities; | |
1249 | ||
1250 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1251 | { |
17c76198 PP |
1252 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1253 | ||
a5f239e4 PP |
1254 | #ifdef HAVE_GNUTLS_PKCS11 |
1255 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1256 | which loads modules from a config file, which sounds good and may be wanted | |
1257 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1258 | environment variables are used and so breaks for users calling mailq. | |
1259 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1260 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1261 | { |
1262 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
47195144 | 1263 | exim_gnutls_err_check(rc, US"gnutls_pkcs11_init"); |
a5f239e4 PP |
1264 | } |
1265 | #endif | |
1266 | ||
17c76198 | 1267 | rc = gnutls_global_init(); |
47195144 | 1268 | exim_gnutls_err_check(rc, US"gnutls_global_init"); |
17c76198 PP |
1269 | |
1270 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1271 | DEBUG(D_tls) | |
059ec3d9 | 1272 | { |
17c76198 PP |
1273 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1274 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1275 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1276 | } |
17c76198 PP |
1277 | #endif |
1278 | ||
4fb7df6d JH |
1279 | #ifndef DISABLE_OCSP |
1280 | if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) | |
9196d5bf | 1281 | log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); |
4fb7df6d | 1282 | #endif |
9196d5bf | 1283 | |
17c76198 | 1284 | exim_gnutls_base_init_done = TRUE; |
059ec3d9 | 1285 | } |
059ec3d9 | 1286 | |
17c76198 PP |
1287 | if (host) |
1288 | { | |
1289 | state = &state_client; | |
1290 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1291 | state->tlsp = &tls_out; |
17c76198 PP |
1292 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1293 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1294 | } | |
1295 | else | |
1296 | { | |
1297 | state = &state_server; | |
1298 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1299 | state->tlsp = &tls_in; |
17c76198 PP |
1300 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1301 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1302 | } | |
47195144 | 1303 | exim_gnutls_err_check(rc, US"gnutls_init"); |
059ec3d9 | 1304 | |
17c76198 | 1305 | state->host = host; |
059ec3d9 | 1306 | |
17c76198 PP |
1307 | state->tls_certificate = certificate; |
1308 | state->tls_privatekey = privatekey; | |
5779e6aa | 1309 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1310 | state->tls_sni = sni; |
1311 | state->tls_verify_certificates = cas; | |
1312 | state->tls_crl = crl; | |
059ec3d9 | 1313 | |
17c76198 PP |
1314 | /* This handles the variables that might get re-expanded after TLS SNI; |
1315 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1316 | |
17c76198 PP |
1317 | DEBUG(D_tls) |
1318 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
cf0c6164 | 1319 | if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; |
059ec3d9 | 1320 | |
1365611d PP |
1321 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1322 | requires a new structure afterwards. */ | |
83da1223 | 1323 | |
cf0c6164 | 1324 | if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; |
83da1223 | 1325 | |
17c76198 PP |
1326 | /* set SNI in client, only */ |
1327 | if (host) | |
1328 | { | |
cf0c6164 | 1329 | if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) |
17c76198 | 1330 | return DEFER; |
0df4ab80 | 1331 | if (state->tlsp->sni && *state->tlsp->sni) |
17c76198 PP |
1332 | { |
1333 | DEBUG(D_tls) | |
0df4ab80 JH |
1334 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); |
1335 | sz = Ustrlen(state->tlsp->sni); | |
17c76198 | 1336 | rc = gnutls_server_name_set(state->session, |
0df4ab80 | 1337 | GNUTLS_NAME_DNS, state->tlsp->sni, sz); |
47195144 | 1338 | exim_gnutls_err_check(rc, US"gnutls_server_name_set"); |
17c76198 PP |
1339 | } |
1340 | } | |
1341 | else if (state->tls_sni) | |
1342 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
ba86e143 | 1343 | "have an SNI set for a server [%s]\n", state->tls_sni); |
83da1223 | 1344 | |
17c76198 | 1345 | /* This is the priority string support, |
42bfef1e | 1346 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1347 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1348 | This was backwards incompatible, but means Exim no longer needs to track | |
1349 | all algorithms and provide string forms for them. */ | |
83da1223 | 1350 | |
17c76198 | 1351 | want_default_priorities = TRUE; |
83da1223 | 1352 | |
17c76198 | 1353 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1354 | { |
cf0c6164 | 1355 | if (!expand_check_tlsvar(tls_require_ciphers, errstr)) |
17c76198 PP |
1356 | return DEFER; |
1357 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1358 | { |
17c76198 PP |
1359 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1360 | state->exp_tls_require_ciphers); | |
1361 | ||
1362 | rc = gnutls_priority_init(&state->priority_cache, | |
1363 | CS state->exp_tls_require_ciphers, &errpos); | |
1364 | want_default_priorities = FALSE; | |
1365 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1366 | } |
1367 | } | |
17c76198 PP |
1368 | if (want_default_priorities) |
1369 | { | |
83e2f8a2 PP |
1370 | DEBUG(D_tls) |
1371 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1372 | exim_default_gnutls_priority); | |
17c76198 PP |
1373 | rc = gnutls_priority_init(&state->priority_cache, |
1374 | exim_default_gnutls_priority, &errpos); | |
1375 | p = US exim_default_gnutls_priority; | |
1376 | } | |
83da1223 | 1377 | |
47195144 | 1378 | exim_gnutls_err_check(rc, string_sprintf( |
17c76198 PP |
1379 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", |
1380 | p, errpos - CS p, errpos)); | |
1381 | ||
1382 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
47195144 | 1383 | exim_gnutls_err_check(rc, US"gnutls_priority_set"); |
17c76198 PP |
1384 | |
1385 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1386 | ||
1387 | /* Reduce security in favour of increased compatibility, if the admin | |
1388 | decides to make that trade-off. */ | |
1389 | if (gnutls_compat_mode) | |
83da1223 | 1390 | { |
17c76198 PP |
1391 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1392 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1393 | gnutls_session_enable_compatibility_mode(state->session); | |
1394 | #else | |
1395 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1396 | #endif | |
83da1223 PH |
1397 | } |
1398 | ||
17c76198 | 1399 | *caller_state = state; |
17c76198 | 1400 | return OK; |
83da1223 PH |
1401 | } |
1402 | ||
1403 | ||
1404 | ||
059ec3d9 | 1405 | /************************************************* |
17c76198 | 1406 | * Extract peer information * |
059ec3d9 PH |
1407 | *************************************************/ |
1408 | ||
17c76198 | 1409 | /* Called from both server and client code. |
4fe99a6c PP |
1410 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1411 | and we use that to detect double-calls. | |
059ec3d9 | 1412 | |
75fe387d PP |
1413 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1414 | for logging in the server side, but for the client side, we log after teardown | |
1415 | in src/deliver.c. While the session is up, we can twist about states and | |
1416 | repoint tls_* globals, but those variables used for logging or other variable | |
1417 | expansion that happens _after_ delivery need to have a longer life-time. | |
1418 | ||
1419 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1420 | doing this more than once per generation of a state context. We set them in | |
1421 | the state context, and repoint tls_* to them. After the state goes away, the | |
1422 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1423 | ||
1424 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1425 | don't apply. | |
1426 | ||
059ec3d9 | 1427 | Arguments: |
17c76198 | 1428 | state exim_gnutls_state_st * |
cf0c6164 | 1429 | errstr pointer to error string |
059ec3d9 | 1430 | |
17c76198 | 1431 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1432 | */ |
1433 | ||
17c76198 | 1434 | static int |
cf0c6164 | 1435 | peer_status(exim_gnutls_state_st *state, uschar ** errstr) |
059ec3d9 | 1436 | { |
75fe387d | 1437 | uschar cipherbuf[256]; |
27f19eb4 | 1438 | const gnutls_datum_t *cert_list; |
75fe387d | 1439 | int old_pool, rc; |
17c76198 | 1440 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1441 | gnutls_protocol_t protocol; |
1442 | gnutls_cipher_algorithm_t cipher; | |
1443 | gnutls_kx_algorithm_t kx; | |
1444 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1445 | gnutls_certificate_type_t ct; |
1446 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1447 | uschar *p, *dn_buf; |
17c76198 | 1448 | size_t sz; |
059ec3d9 | 1449 | |
4fe99a6c | 1450 | if (state->have_set_peerdn) |
17c76198 | 1451 | return OK; |
4fe99a6c | 1452 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1453 | |
4fe99a6c | 1454 | state->peerdn = NULL; |
059ec3d9 | 1455 | |
4fe99a6c PP |
1456 | /* tls_cipher */ |
1457 | cipher = gnutls_cipher_get(state->session); | |
1458 | protocol = gnutls_protocol_get_version(state->session); | |
1459 | mac = gnutls_mac_get(state->session); | |
1460 | kx = gnutls_kx_get(state->session); | |
1461 | ||
75fe387d | 1462 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1463 | "%s:%s:%d", |
1464 | gnutls_protocol_get_name(protocol), | |
1465 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1466 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1467 | ||
1468 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1469 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1470 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1471 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1472 | if (isspace(*p)) |
1473 | *p = '-'; | |
75fe387d PP |
1474 | old_pool = store_pool; |
1475 | store_pool = POOL_PERM; | |
1476 | state->ciphersuite = string_copy(cipherbuf); | |
1477 | store_pool = old_pool; | |
817d9f57 | 1478 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1479 | |
1480 | /* tls_peerdn */ | |
17c76198 | 1481 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1482 | |
17c76198 PP |
1483 | if (cert_list == NULL || cert_list_size == 0) |
1484 | { | |
17c76198 PP |
1485 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1486 | cert_list, cert_list_size); | |
e51c7be2 | 1487 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1488 | return tls_error(US"certificate verification failed", |
cf0c6164 | 1489 | "no certificate received from peer", state->host, errstr); |
17c76198 PP |
1490 | return OK; |
1491 | } | |
059ec3d9 | 1492 | |
17c76198 PP |
1493 | ct = gnutls_certificate_type_get(state->session); |
1494 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1495 | { |
17c76198 | 1496 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1497 | DEBUG(D_tls) |
1498 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1499 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1500 | return tls_error(US"certificate verification not possible, unhandled type", |
cf0c6164 | 1501 | ctn, state->host, errstr); |
17c76198 | 1502 | return OK; |
83da1223 | 1503 | } |
059ec3d9 | 1504 | |
e51c7be2 JH |
1505 | #define exim_gnutls_peer_err(Label) \ |
1506 | do { \ | |
1507 | if (rc != GNUTLS_E_SUCCESS) \ | |
1508 | { \ | |
1509 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1510 | (Label), gnutls_strerror(rc)); \ | |
1511 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
cf0c6164 | 1512 | return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ |
e51c7be2 JH |
1513 | return OK; \ |
1514 | } \ | |
1515 | } while (0) | |
17c76198 | 1516 | |
9d1c15ef JH |
1517 | rc = import_cert(&cert_list[0], &crt); |
1518 | exim_gnutls_peer_err(US"cert 0"); | |
1519 | ||
1520 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1521 | |
17c76198 PP |
1522 | sz = 0; |
1523 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1524 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1525 | { |
17c76198 PP |
1526 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1527 | return FAIL; /* should not happen */ | |
059ec3d9 | 1528 | } |
17c76198 PP |
1529 | dn_buf = store_get_perm(sz); |
1530 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1531 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1532 | |
17c76198 PP |
1533 | state->peerdn = dn_buf; |
1534 | ||
1535 | return OK; | |
1536 | #undef exim_gnutls_peer_err | |
1537 | } | |
059ec3d9 | 1538 | |
059ec3d9 | 1539 | |
059ec3d9 | 1540 | |
059ec3d9 | 1541 | |
17c76198 PP |
1542 | /************************************************* |
1543 | * Verify peer certificate * | |
1544 | *************************************************/ | |
059ec3d9 | 1545 | |
17c76198 PP |
1546 | /* Called from both server and client code. |
1547 | *Should* be using a callback registered with | |
1548 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1549 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1550 | |
17c76198 PP |
1551 | Arguments: |
1552 | state exim_gnutls_state_st * | |
cf0c6164 | 1553 | errstr where to put an error message |
059ec3d9 | 1554 | |
17c76198 PP |
1555 | Returns: |
1556 | FALSE if the session should be rejected | |
1557 | TRUE if the cert is okay or we just don't care | |
1558 | */ | |
059ec3d9 | 1559 | |
17c76198 | 1560 | static BOOL |
cf0c6164 | 1561 | verify_certificate(exim_gnutls_state_st *state, uschar ** errstr) |
17c76198 PP |
1562 | { |
1563 | int rc; | |
1564 | unsigned int verify; | |
1565 | ||
cf0c6164 | 1566 | *errstr = NULL; |
17c76198 | 1567 | |
cf0c6164 | 1568 | if ((rc = peer_status(state, errstr)) != OK) |
e6060e2c | 1569 | { |
17c76198 | 1570 | verify = GNUTLS_CERT_INVALID; |
cf0c6164 | 1571 | *errstr = US"certificate not supplied"; |
17c76198 PP |
1572 | } |
1573 | else | |
17c76198 | 1574 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1575 | |
17c76198 PP |
1576 | /* Handle the result of verification. INVALID seems to be set as well |
1577 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1578 | |
e51c7be2 JH |
1579 | if (rc < 0 || |
1580 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1581 | ) | |
17c76198 PP |
1582 | { |
1583 | state->peer_cert_verified = FALSE; | |
cf0c6164 JH |
1584 | if (!*errstr) |
1585 | *errstr = verify & GNUTLS_CERT_REVOKED | |
1586 | ? US"certificate revoked" : US"certificate invalid"; | |
059ec3d9 | 1587 | |
17c76198 | 1588 | DEBUG(D_tls) |
e51c7be2 | 1589 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
cf0c6164 | 1590 | *errstr, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1591 | |
e51c7be2 | 1592 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1593 | { |
e51c7be2 JH |
1594 | gnutls_alert_send(state->session, |
1595 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1596 | return FALSE; |
1597 | } | |
1598 | DEBUG(D_tls) | |
4789da3a | 1599 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1600 | } |
e51c7be2 | 1601 | |
17c76198 PP |
1602 | else |
1603 | { | |
aa2a70ba | 1604 | if (state->exp_tls_verify_cert_hostnames) |
e51c7be2 JH |
1605 | { |
1606 | int sep = 0; | |
55414b25 | 1607 | const uschar * list = state->exp_tls_verify_cert_hostnames; |
e51c7be2 | 1608 | uschar * name; |
76075bb5 | 1609 | while ((name = string_nextinlist(&list, &sep, NULL, 0))) |
e51c7be2 JH |
1610 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) |
1611 | break; | |
1612 | if (!name) | |
1613 | { | |
1614 | DEBUG(D_tls) | |
1615 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
aa2a70ba JH |
1616 | if (state->verify_requirement >= VERIFY_REQUIRED) |
1617 | { | |
1618 | gnutls_alert_send(state->session, | |
1619 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1620 | return FALSE; | |
1621 | } | |
1622 | return TRUE; | |
e51c7be2 JH |
1623 | } |
1624 | } | |
17c76198 | 1625 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1626 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1627 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1628 | } |
059ec3d9 | 1629 | |
817d9f57 | 1630 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1631 | |
17c76198 PP |
1632 | return TRUE; |
1633 | } | |
059ec3d9 | 1634 | |
17c76198 PP |
1635 | |
1636 | ||
1637 | ||
1638 | /* ------------------------------------------------------------------------ */ | |
1639 | /* Callbacks */ | |
1640 | ||
1641 | /* Logging function which can be registered with | |
1642 | * gnutls_global_set_log_function() | |
1643 | * gnutls_global_set_log_level() 0..9 | |
1644 | */ | |
af3498d6 | 1645 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1646 | static void |
17c76198 | 1647 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1648 | { |
8c79eebf PP |
1649 | size_t len = strlen(message); |
1650 | if (len < 1) | |
1651 | { | |
1652 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1653 | return; | |
1654 | } | |
1655 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1656 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1657 | } |
af3498d6 | 1658 | #endif |
059ec3d9 | 1659 | |
059ec3d9 | 1660 | |
17c76198 PP |
1661 | /* Called after client hello, should handle SNI work. |
1662 | This will always set tls_sni (state->received_sni) if available, | |
1663 | and may trigger presenting different certificates, | |
1664 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1665 | |
17c76198 PP |
1666 | Should be registered with |
1667 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1668 | |
17c76198 PP |
1669 | "This callback must return 0 on success or a gnutls error code to terminate the |
1670 | handshake.". | |
059ec3d9 | 1671 | |
17c76198 PP |
1672 | For inability to get SNI information, we return 0. |
1673 | We only return non-zero if re-setup failed. | |
817d9f57 | 1674 | Only used for server-side TLS. |
17c76198 | 1675 | */ |
44bbabb5 | 1676 | |
17c76198 PP |
1677 | static int |
1678 | exim_sni_handling_cb(gnutls_session_t session) | |
1679 | { | |
1680 | char sni_name[MAX_HOST_LEN]; | |
1681 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1682 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1683 | unsigned int sni_type; |
1684 | int rc, old_pool; | |
cf0c6164 | 1685 | uschar * dummy_errstr; |
17c76198 PP |
1686 | |
1687 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1688 | if (rc != GNUTLS_E_SUCCESS) |
1689 | { | |
1690 | DEBUG(D_tls) { | |
1691 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1692 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1693 | else | |
1694 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1695 | gnutls_strerror(rc), rc); | |
cf0c6164 | 1696 | } |
b34fc30c PP |
1697 | return 0; |
1698 | } | |
1699 | ||
17c76198 PP |
1700 | if (sni_type != GNUTLS_NAME_DNS) |
1701 | { | |
1702 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1703 | return 0; | |
1704 | } | |
44bbabb5 | 1705 | |
17c76198 PP |
1706 | /* We now have a UTF-8 string in sni_name */ |
1707 | old_pool = store_pool; | |
1708 | store_pool = POOL_PERM; | |
1709 | state->received_sni = string_copyn(US sni_name, data_len); | |
1710 | store_pool = old_pool; | |
1711 | ||
1712 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1713 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1714 | |
1715 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1716 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1717 | ||
1718 | if (!state->trigger_sni_changes) | |
1719 | return 0; | |
1720 | ||
cf0c6164 | 1721 | if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) |
17c76198 PP |
1722 | { |
1723 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1724 | been offered. The best we can do now is abort. */ | |
1725 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1726 | } | |
1727 | ||
cf0c6164 | 1728 | rc = tls_set_remaining_x509(state, &dummy_errstr); |
1365611d PP |
1729 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; |
1730 | ||
1731 | return 0; | |
059ec3d9 PH |
1732 | } |
1733 | ||
1734 | ||
1735 | ||
f2de3a33 | 1736 | #ifndef DISABLE_OCSP |
44662487 JH |
1737 | |
1738 | static int | |
1739 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1740 | gnutls_datum_t * ocsp_response) | |
1741 | { | |
1742 | int ret; | |
47195144 | 1743 | DEBUG(D_tls) debug_printf("OCSP stapling callback: %s\n", US ptr); |
44662487 | 1744 | |
44662487 JH |
1745 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1746 | { | |
1747 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
5903c6ff | 1748 | CS ptr); |
018058b2 | 1749 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1750 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1751 | } | |
1752 | ||
018058b2 | 1753 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1754 | return 0; |
1755 | } | |
1756 | ||
1757 | #endif | |
1758 | ||
1759 | ||
0cbf2b82 | 1760 | #ifndef DISABLE_EVENT |
a7538db1 JH |
1761 | /* |
1762 | We use this callback to get observability and detail-level control | |
723fe533 JH |
1763 | for an exim TLS connection (either direction), raising a tls:cert event |
1764 | for each cert in the chain presented by the peer. Any event | |
a7538db1 JH |
1765 | can deny verification. |
1766 | ||
1767 | Return 0 for the handshake to continue or non-zero to terminate. | |
1768 | */ | |
1769 | ||
1770 | static int | |
723fe533 | 1771 | verify_cb(gnutls_session_t session) |
a7538db1 | 1772 | { |
27f19eb4 | 1773 | const gnutls_datum_t * cert_list; |
a7538db1 JH |
1774 | unsigned int cert_list_size = 0; |
1775 | gnutls_x509_crt_t crt; | |
1776 | int rc; | |
b30275b8 | 1777 | uschar * yield; |
a7538db1 JH |
1778 | exim_gnutls_state_st * state = gnutls_session_get_ptr(session); |
1779 | ||
1780 | cert_list = gnutls_certificate_get_peers(session, &cert_list_size); | |
1781 | if (cert_list) | |
1782 | while (cert_list_size--) | |
1783 | { | |
1784 | rc = import_cert(&cert_list[cert_list_size], &crt); | |
1785 | if (rc != GNUTLS_E_SUCCESS) | |
1786 | { | |
1787 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", | |
1788 | cert_list_size, gnutls_strerror(rc)); | |
1789 | break; | |
1790 | } | |
1791 | ||
1792 | state->tlsp->peercert = crt; | |
b30275b8 JH |
1793 | if ((yield = event_raise(state->event_action, |
1794 | US"tls:cert", string_sprintf("%d", cert_list_size)))) | |
a7538db1 JH |
1795 | { |
1796 | log_write(0, LOG_MAIN, | |
b30275b8 JH |
1797 | "SSL verify denied by event-action: depth=%d: %s", |
1798 | cert_list_size, yield); | |
a7538db1 JH |
1799 | return 1; /* reject */ |
1800 | } | |
1801 | state->tlsp->peercert = NULL; | |
1802 | } | |
1803 | ||
1804 | return 0; | |
1805 | } | |
1806 | ||
1807 | #endif | |
44662487 JH |
1808 | |
1809 | ||
17c76198 PP |
1810 | |
1811 | /* ------------------------------------------------------------------------ */ | |
1812 | /* Exported functions */ | |
1813 | ||
1814 | ||
1815 | ||
1816 | ||
059ec3d9 PH |
1817 | /************************************************* |
1818 | * Start a TLS session in a server * | |
1819 | *************************************************/ | |
1820 | ||
1821 | /* This is called when Exim is running as a server, after having received | |
1822 | the STARTTLS command. It must respond to that command, and then negotiate | |
1823 | a TLS session. | |
1824 | ||
1825 | Arguments: | |
83da1223 | 1826 | require_ciphers list of allowed ciphers or NULL |
cf0c6164 | 1827 | errstr pointer to error string |
059ec3d9 PH |
1828 | |
1829 | Returns: OK on success | |
1830 | DEFER for errors before the start of the negotiation | |
4c04137d | 1831 | FAIL for errors during the negotiation; the server can't |
059ec3d9 PH |
1832 | continue running. |
1833 | */ | |
1834 | ||
1835 | int | |
cf0c6164 | 1836 | tls_server_start(const uschar * require_ciphers, uschar ** errstr) |
059ec3d9 PH |
1837 | { |
1838 | int rc; | |
cf0c6164 | 1839 | exim_gnutls_state_st * state = NULL; |
059ec3d9 PH |
1840 | |
1841 | /* Check for previous activation */ | |
817d9f57 | 1842 | if (tls_in.active >= 0) |
059ec3d9 | 1843 | { |
cf0c6164 | 1844 | tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); |
925ac8e4 | 1845 | smtp_printf("554 Already in TLS\r\n", FALSE); |
059ec3d9 PH |
1846 | return FAIL; |
1847 | } | |
1848 | ||
1849 | /* Initialize the library. If it fails, it will already have logged the error | |
1850 | and sent an SMTP response. */ | |
1851 | ||
17c76198 | 1852 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1853 | |
cf0c6164 | 1854 | if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, |
17c76198 | 1855 | NULL, tls_verify_certificates, tls_crl, |
cf0c6164 | 1856 | require_ciphers, &state, errstr)) != OK) return rc; |
059ec3d9 | 1857 | |
059ec3d9 PH |
1858 | /* If this is a host for which certificate verification is mandatory or |
1859 | optional, set up appropriately. */ | |
1860 | ||
059ec3d9 | 1861 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1862 | { |
e51c7be2 JH |
1863 | DEBUG(D_tls) |
1864 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1865 | state->verify_requirement = VERIFY_REQUIRED; |
1866 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1867 | } | |
059ec3d9 | 1868 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1869 | { |
e51c7be2 JH |
1870 | DEBUG(D_tls) |
1871 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1872 | state->verify_requirement = VERIFY_OPTIONAL; |
1873 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1874 | } | |
1875 | else | |
1876 | { | |
e51c7be2 JH |
1877 | DEBUG(D_tls) |
1878 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1879 | state->verify_requirement = VERIFY_NONE; |
1880 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1881 | } | |
059ec3d9 | 1882 | |
0cbf2b82 | 1883 | #ifndef DISABLE_EVENT |
723fe533 JH |
1884 | if (event_action) |
1885 | { | |
1886 | state->event_action = event_action; | |
1887 | gnutls_session_set_ptr(state->session, state); | |
1888 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); | |
1889 | } | |
1890 | #endif | |
1891 | ||
17c76198 PP |
1892 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1893 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1894 | |
17c76198 PP |
1895 | gnutls_handshake_set_post_client_hello_function(state->session, |
1896 | exim_sni_handling_cb); | |
059ec3d9 PH |
1897 | |
1898 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1899 | on connection, where outputting anything now upsets the clients and tends to | |
1900 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1901 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1902 | mode, the fflush() happens when smtp_getc() is called. */ | |
1903 | ||
817d9f57 | 1904 | if (!state->tlsp->on_connect) |
059ec3d9 | 1905 | { |
925ac8e4 | 1906 | smtp_printf("220 TLS go ahead\r\n", FALSE); |
9d1c15ef | 1907 | fflush(smtp_out); |
059ec3d9 PH |
1908 | } |
1909 | ||
1910 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1911 | that the GnuTLS library doesn't. */ | |
1912 | ||
17c76198 | 1913 | gnutls_transport_set_ptr2(state->session, |
27f19eb4 JH |
1914 | (gnutls_transport_ptr_t)(long) fileno(smtp_in), |
1915 | (gnutls_transport_ptr_t)(long) fileno(smtp_out)); | |
17c76198 PP |
1916 | state->fd_in = fileno(smtp_in); |
1917 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1918 | |
1919 | sigalrm_seen = FALSE; | |
1920 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1921 | do |
17c76198 | 1922 | rc = gnutls_handshake(state->session); |
157a7880 | 1923 | while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); |
059ec3d9 PH |
1924 | alarm(0); |
1925 | ||
17c76198 | 1926 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1927 | { |
059ec3d9 PH |
1928 | /* It seems that, except in the case of a timeout, we have to close the |
1929 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1930 | until the server times out. */ | |
1931 | ||
60d10ce7 | 1932 | if (sigalrm_seen) |
ad7fc6eb | 1933 | { |
cf0c6164 | 1934 | tls_error(US"gnutls_handshake", "timed out", NULL, errstr); |
ad7fc6eb JH |
1935 | gnutls_db_remove_session(state->session); |
1936 | } | |
60d10ce7 | 1937 | else |
059ec3d9 | 1938 | { |
cf0c6164 | 1939 | tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); |
f5d25c2b | 1940 | (void) gnutls_alert_send_appropriate(state->session, rc); |
ad7fc6eb | 1941 | gnutls_deinit(state->session); |
ed62aae3 | 1942 | gnutls_certificate_free_credentials(state->x509_cred); |
60d10ce7 | 1943 | millisleep(500); |
ad7fc6eb | 1944 | shutdown(state->fd_out, SHUT_WR); |
60d10ce7 | 1945 | for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ |
f1e894f3 PH |
1946 | (void)fclose(smtp_out); |
1947 | (void)fclose(smtp_in); | |
60d10ce7 | 1948 | smtp_out = smtp_in = NULL; |
059ec3d9 PH |
1949 | } |
1950 | ||
1951 | return FAIL; | |
1952 | } | |
1953 | ||
1954 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1955 | ||
17c76198 PP |
1956 | /* Verify after the fact */ |
1957 | ||
9d1c15ef | 1958 | if ( state->verify_requirement != VERIFY_NONE |
cf0c6164 | 1959 | && !verify_certificate(state, errstr)) |
059ec3d9 | 1960 | { |
9d1c15ef | 1961 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1962 | { |
cf0c6164 | 1963 | (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); |
9d1c15ef | 1964 | return FAIL; |
17c76198 | 1965 | } |
9d1c15ef JH |
1966 | DEBUG(D_tls) |
1967 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
cf0c6164 | 1968 | *errstr); |
059ec3d9 PH |
1969 | } |
1970 | ||
17c76198 PP |
1971 | /* Figure out peer DN, and if authenticated, etc. */ |
1972 | ||
cf0c6164 | 1973 | if ((rc = peer_status(state, NULL)) != OK) return rc; |
17c76198 PP |
1974 | |
1975 | /* Sets various Exim expansion variables; always safe within server */ | |
1976 | ||
9d1c15ef | 1977 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1978 | |
1979 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1980 | and initialize appropriately. */ | |
1981 | ||
17c76198 | 1982 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1983 | |
1984 | receive_getc = tls_getc; | |
0d81dabc | 1985 | receive_getbuf = tls_getbuf; |
584e96c6 | 1986 | receive_get_cache = tls_get_cache; |
059ec3d9 PH |
1987 | receive_ungetc = tls_ungetc; |
1988 | receive_feof = tls_feof; | |
1989 | receive_ferror = tls_ferror; | |
58eb016e | 1990 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1991 | |
059ec3d9 PH |
1992 | return OK; |
1993 | } | |
1994 | ||
1995 | ||
1996 | ||
1997 | ||
aa2a70ba JH |
1998 | static void |
1999 | tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, | |
2000 | smtp_transport_options_block * ob) | |
2001 | { | |
5130845b | 2002 | if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) |
aa2a70ba | 2003 | { |
4af0d74a | 2004 | state->exp_tls_verify_cert_hostnames = |
8c5d388a | 2005 | #ifdef SUPPORT_I18N |
4af0d74a JH |
2006 | string_domain_utf8_to_alabel(host->name, NULL); |
2007 | #else | |
2008 | host->name; | |
2009 | #endif | |
aa2a70ba JH |
2010 | DEBUG(D_tls) |
2011 | debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", | |
2012 | state->exp_tls_verify_cert_hostnames); | |
2013 | } | |
2014 | } | |
aa2a70ba JH |
2015 | |
2016 | ||
059ec3d9 PH |
2017 | /************************************************* |
2018 | * Start a TLS session in a client * | |
2019 | *************************************************/ | |
2020 | ||
2021 | /* Called from the smtp transport after STARTTLS has been accepted. | |
2022 | ||
2023 | Arguments: | |
2024 | fd the fd of the connection | |
2025 | host connected host (for messages) | |
83da1223 | 2026 | addr the first address (not used) |
a7538db1 | 2027 | tb transport (always smtp) |
059ec3d9 | 2028 | |
cf0c6164 JH |
2029 | errstr error string pointer |
2030 | ||
059ec3d9 PH |
2031 | Returns: OK/DEFER/FAIL (because using common functions), |
2032 | but for a client, DEFER and FAIL have the same meaning | |
2033 | */ | |
2034 | ||
2035 | int | |
17c76198 | 2036 | tls_client_start(int fd, host_item *host, |
f5d78688 | 2037 | address_item *addr ARG_UNUSED, |
cf0c6164 | 2038 | transport_instance * tb, |
0e66b3b6 | 2039 | #ifdef EXPERIMENTAL_DANE |
cf0c6164 | 2040 | dns_answer * tlsa_dnsa ARG_UNUSED, |
0e66b3b6 | 2041 | #endif |
cf0c6164 | 2042 | uschar ** errstr) |
059ec3d9 | 2043 | { |
a7538db1 JH |
2044 | smtp_transport_options_block *ob = |
2045 | (smtp_transport_options_block *)tb->options_block; | |
059ec3d9 | 2046 | int rc; |
17c76198 | 2047 | exim_gnutls_state_st *state = NULL; |
f2de3a33 | 2048 | #ifndef DISABLE_OCSP |
5130845b JH |
2049 | BOOL require_ocsp = |
2050 | verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; | |
44662487 | 2051 | BOOL request_ocsp = require_ocsp ? TRUE |
5130845b | 2052 | : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; |
2b4a568d | 2053 | #endif |
059ec3d9 | 2054 | |
17c76198 | 2055 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 2056 | |
65867078 JH |
2057 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
2058 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
cf0c6164 | 2059 | ob->tls_require_ciphers, &state, errstr)) != OK) |
2b4a568d | 2060 | return rc; |
059ec3d9 | 2061 | |
54c90be1 | 2062 | { |
65867078 JH |
2063 | int dh_min_bits = ob->tls_dh_min_bits; |
2064 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
2065 | { | |
2066 | DEBUG(D_tls) | |
2067 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
2068 | " clamping %d up to %d\n", | |
2069 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
2070 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
2071 | } | |
54c90be1 | 2072 | |
65867078 JH |
2073 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
2074 | " acceptable bits to %d\n", | |
2075 | dh_min_bits); | |
2076 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
2077 | } | |
83da1223 | 2078 | |
94431adb | 2079 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
2b4a568d JH |
2080 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only |
2081 | the specified host patterns if one of them is defined */ | |
2082 | ||
aa2a70ba JH |
2083 | if ( ( state->exp_tls_verify_certificates |
2084 | && !ob->tls_verify_hosts | |
610ff438 | 2085 | && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) |
aa2a70ba | 2086 | ) |
5130845b | 2087 | || verify_check_given_host(&ob->tls_verify_hosts, host) == OK |
2b4a568d | 2088 | ) |
17c76198 | 2089 | { |
aa2a70ba | 2090 | tls_client_setup_hostname_checks(host, state, ob); |
aa2a70ba JH |
2091 | DEBUG(D_tls) |
2092 | debug_printf("TLS: server certificate verification required.\n"); | |
2093 | state->verify_requirement = VERIFY_REQUIRED; | |
52f93eed WB |
2094 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
2095 | } | |
5130845b | 2096 | else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) |
52f93eed | 2097 | { |
aa2a70ba | 2098 | tls_client_setup_hostname_checks(host, state, ob); |
e51c7be2 JH |
2099 | DEBUG(D_tls) |
2100 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 2101 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
2102 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
2103 | } | |
2104 | else | |
2105 | { | |
e51c7be2 JH |
2106 | DEBUG(D_tls) |
2107 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
2108 | state->verify_requirement = VERIFY_NONE; |
2109 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 2110 | } |
059ec3d9 | 2111 | |
f2de3a33 JH |
2112 | #ifndef DISABLE_OCSP |
2113 | /* supported since GnuTLS 3.1.3 */ | |
44662487 | 2114 | if (request_ocsp) |
9d1c15ef JH |
2115 | { |
2116 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
2117 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
2118 | NULL, 0, NULL)) != OK) | |
9d1c15ef | 2119 | return tls_error(US"cert-status-req", |
cf0c6164 | 2120 | gnutls_strerror(rc), state->host, errstr); |
44662487 | 2121 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 2122 | } |
2b4a568d JH |
2123 | #endif |
2124 | ||
0cbf2b82 | 2125 | #ifndef DISABLE_EVENT |
774ef2d7 | 2126 | if (tb->event_action) |
a7538db1 | 2127 | { |
774ef2d7 | 2128 | state->event_action = tb->event_action; |
a7538db1 | 2129 | gnutls_session_set_ptr(state->session, state); |
723fe533 | 2130 | gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); |
a7538db1 JH |
2131 | } |
2132 | #endif | |
2133 | ||
27f19eb4 | 2134 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(long) fd); |
17c76198 PP |
2135 | state->fd_in = fd; |
2136 | state->fd_out = fd; | |
059ec3d9 | 2137 | |
9d1c15ef | 2138 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
2139 | /* There doesn't seem to be a built-in timeout on connection. */ |
2140 | ||
2141 | sigalrm_seen = FALSE; | |
65867078 | 2142 | alarm(ob->command_timeout); |
17c76198 PP |
2143 | do |
2144 | { | |
2145 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
2146 | } while ((rc == GNUTLS_E_AGAIN) || |
2147 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
2148 | alarm(0); |
2149 | ||
4fe99a6c | 2150 | if (rc != GNUTLS_E_SUCCESS) |
60d10ce7 JH |
2151 | if (sigalrm_seen) |
2152 | { | |
2153 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); | |
cf0c6164 | 2154 | return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); |
60d10ce7 JH |
2155 | } |
2156 | else | |
cf0c6164 | 2157 | return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); |
4fe99a6c | 2158 | |
17c76198 | 2159 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 2160 | |
17c76198 | 2161 | /* Verify late */ |
059ec3d9 | 2162 | |
17c76198 | 2163 | if (state->verify_requirement != VERIFY_NONE && |
cf0c6164 JH |
2164 | !verify_certificate(state, errstr)) |
2165 | return tls_error(US"certificate verification failed", *errstr, state->host, errstr); | |
059ec3d9 | 2166 | |
f2de3a33 | 2167 | #ifndef DISABLE_OCSP |
2b4a568d JH |
2168 | if (require_ocsp) |
2169 | { | |
2170 | DEBUG(D_tls) | |
2171 | { | |
2172 | gnutls_datum_t stapling; | |
2173 | gnutls_ocsp_resp_t resp; | |
2174 | gnutls_datum_t printed; | |
2175 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
2176 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
2177 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
2178 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
2179 | ) | |
2180 | { | |
65867078 | 2181 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
2182 | gnutls_free(printed.data); |
2183 | } | |
2184 | else | |
cf0c6164 | 2185 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host, errstr); |
2b4a568d JH |
2186 | } |
2187 | ||
2b4a568d | 2188 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
2189 | { |
2190 | tls_out.ocsp = OCSP_FAILED; | |
cf0c6164 | 2191 | return tls_error(US"certificate status check failed", NULL, state->host, errstr); |
018058b2 | 2192 | } |
2b4a568d | 2193 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 2194 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
2195 | } |
2196 | #endif | |
2197 | ||
17c76198 | 2198 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 2199 | |
cf0c6164 | 2200 | if ((rc = peer_status(state, errstr)) != OK) |
2b4a568d | 2201 | return rc; |
059ec3d9 | 2202 | |
4fe99a6c | 2203 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 2204 | |
9d1c15ef | 2205 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 2206 | |
059ec3d9 PH |
2207 | return OK; |
2208 | } | |
2209 | ||
2210 | ||
2211 | ||
17c76198 | 2212 | |
059ec3d9 | 2213 | /************************************************* |
17c76198 | 2214 | * Close down a TLS session * |
059ec3d9 PH |
2215 | *************************************************/ |
2216 | ||
17c76198 PP |
2217 | /* This is also called from within a delivery subprocess forked from the |
2218 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
2219 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 2220 | |
17c76198 PP |
2221 | Arguments: TRUE if gnutls_bye is to be called |
2222 | Returns: nothing | |
059ec3d9 PH |
2223 | */ |
2224 | ||
17c76198 | 2225 | void |
817d9f57 | 2226 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 2227 | { |
817d9f57 | 2228 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2229 | |
389ca47a | 2230 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
2231 | |
2232 | if (shutdown) | |
2233 | { | |
f5723109 | 2234 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); |
17c76198 PP |
2235 | gnutls_bye(state->session, GNUTLS_SHUT_WR); |
2236 | } | |
2237 | ||
2238 | gnutls_deinit(state->session); | |
ed62aae3 HSHR |
2239 | gnutls_certificate_free_credentials(state->x509_cred); |
2240 | ||
17c76198 | 2241 | |
389ca47a | 2242 | state->tlsp->active = -1; |
17c76198 PP |
2243 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
2244 | ||
2245 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
2246 | { | |
2247 | gnutls_global_deinit(); | |
2248 | exim_gnutls_base_init_done = FALSE; | |
2249 | } | |
059ec3d9 PH |
2250 | } |
2251 | ||
2252 | ||
2253 | ||
17c76198 | 2254 | |
0d81dabc JH |
2255 | static BOOL |
2256 | tls_refill(unsigned lim) | |
2257 | { | |
2258 | exim_gnutls_state_st * state = &state_server; | |
2259 | ssize_t inbytes; | |
2260 | ||
2261 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", | |
2262 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
2263 | ||
2264 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
2265 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, | |
2266 | MIN(ssl_xfer_buffer_size, lim)); | |
2267 | alarm(0); | |
2268 | ||
2269 | /* Timeouts do not get this far; see command_timeout_handler(). | |
2270 | A zero-byte return appears to mean that the TLS session has been | |
2271 | closed down, not that the socket itself has been closed down. Revert to | |
2272 | non-TLS handling. */ | |
2273 | ||
2274 | if (sigalrm_seen) | |
2275 | { | |
2276 | DEBUG(D_tls) debug_printf("Got tls read timeout\n"); | |
2277 | state->xfer_error = 1; | |
2278 | return FALSE; | |
2279 | } | |
2280 | ||
2281 | else if (inbytes == 0) | |
2282 | { | |
2283 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2284 | ||
2285 | receive_getc = smtp_getc; | |
2286 | receive_getbuf = smtp_getbuf; | |
2287 | receive_get_cache = smtp_get_cache; | |
2288 | receive_ungetc = smtp_ungetc; | |
2289 | receive_feof = smtp_feof; | |
2290 | receive_ferror = smtp_ferror; | |
2291 | receive_smtp_buffered = smtp_buffered; | |
2292 | ||
2293 | gnutls_deinit(state->session); | |
2294 | gnutls_certificate_free_credentials(state->x509_cred); | |
2295 | ||
2296 | state->session = NULL; | |
2297 | state->tlsp->active = -1; | |
2298 | state->tlsp->bits = 0; | |
2299 | state->tlsp->certificate_verified = FALSE; | |
2300 | tls_channelbinding_b64 = NULL; | |
2301 | state->tlsp->cipher = NULL; | |
2302 | state->tlsp->peercert = NULL; | |
2303 | state->tlsp->peerdn = NULL; | |
2304 | ||
2305 | return FALSE; | |
2306 | } | |
2307 | ||
2308 | /* Handle genuine errors */ | |
2309 | ||
2310 | else if (inbytes < 0) | |
2311 | { | |
2312 | record_io_error(state, (int) inbytes, US"recv", NULL); | |
2313 | state->xfer_error = 1; | |
2314 | return FALSE; | |
2315 | } | |
2316 | #ifndef DISABLE_DKIM | |
2317 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); | |
2318 | #endif | |
2319 | state->xfer_buffer_hwm = (int) inbytes; | |
2320 | state->xfer_buffer_lwm = 0; | |
2321 | return TRUE; | |
2322 | } | |
2323 | ||
059ec3d9 PH |
2324 | /************************************************* |
2325 | * TLS version of getc * | |
2326 | *************************************************/ | |
2327 | ||
2328 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
2329 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 2330 | Only used by the server-side TLS. |
059ec3d9 | 2331 | |
17c76198 PP |
2332 | This feeds DKIM and should be used for all message-body reads. |
2333 | ||
bd8fbe36 | 2334 | Arguments: lim Maximum amount to read/bufffer |
059ec3d9 PH |
2335 | Returns: the next character or EOF |
2336 | */ | |
2337 | ||
2338 | int | |
bd8fbe36 | 2339 | tls_getc(unsigned lim) |
059ec3d9 | 2340 | { |
0d81dabc | 2341 | exim_gnutls_state_st * state = &state_server; |
059ec3d9 | 2342 | |
0d81dabc JH |
2343 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2344 | if (!tls_refill(lim)) | |
2345 | return state->xfer_error ? EOF : smtp_getc(lim); | |
ed62aae3 | 2346 | |
0d81dabc | 2347 | /* Something in the buffer; return next uschar */ |
059ec3d9 | 2348 | |
0d81dabc JH |
2349 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
2350 | } | |
059ec3d9 | 2351 | |
0d81dabc JH |
2352 | uschar * |
2353 | tls_getbuf(unsigned * len) | |
2354 | { | |
2355 | exim_gnutls_state_st * state = &state_server; | |
2356 | unsigned size; | |
2357 | uschar * buf; | |
059ec3d9 | 2358 | |
0d81dabc JH |
2359 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
2360 | if (!tls_refill(*len)) | |
059ec3d9 | 2361 | { |
0d81dabc JH |
2362 | if (!state->xfer_error) return smtp_getbuf(len); |
2363 | *len = 0; | |
2364 | return NULL; | |
059ec3d9 | 2365 | } |
059ec3d9 | 2366 | |
0d81dabc JH |
2367 | if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) |
2368 | size = *len; | |
2369 | buf = &state->xfer_buffer[state->xfer_buffer_lwm]; | |
2370 | state->xfer_buffer_lwm += size; | |
2371 | *len = size; | |
2372 | return buf; | |
059ec3d9 PH |
2373 | } |
2374 | ||
0d81dabc | 2375 | |
584e96c6 JH |
2376 | void |
2377 | tls_get_cache() | |
2378 | { | |
9960d1e5 | 2379 | #ifndef DISABLE_DKIM |
584e96c6 JH |
2380 | exim_gnutls_state_st * state = &state_server; |
2381 | int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; | |
2382 | if (n > 0) | |
2383 | dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); | |
584e96c6 | 2384 | #endif |
9960d1e5 | 2385 | } |
584e96c6 | 2386 | |
059ec3d9 | 2387 | |
925ac8e4 JH |
2388 | BOOL |
2389 | tls_could_read(void) | |
2390 | { | |
2391 | return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm | |
2392 | || gnutls_record_check_pending(state_server.session) > 0; | |
2393 | } | |
2394 | ||
2395 | ||
059ec3d9 | 2396 | |
17c76198 | 2397 | |
059ec3d9 PH |
2398 | /************************************************* |
2399 | * Read bytes from TLS channel * | |
2400 | *************************************************/ | |
2401 | ||
17c76198 PP |
2402 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2403 | then the caller must feed DKIM. | |
817d9f57 | 2404 | |
059ec3d9 PH |
2405 | Arguments: |
2406 | buff buffer of data | |
2407 | len size of buffer | |
2408 | ||
2409 | Returns: the number of bytes read | |
2410 | -1 after a failed read | |
2411 | */ | |
2412 | ||
2413 | int | |
817d9f57 | 2414 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2415 | { |
817d9f57 | 2416 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2417 | ssize_t inbytes; |
059ec3d9 | 2418 | |
17c76198 PP |
2419 | if (len > INT_MAX) |
2420 | len = INT_MAX; | |
059ec3d9 | 2421 | |
17c76198 PP |
2422 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2423 | DEBUG(D_tls) | |
2424 | debug_printf("*** PROBABLY A BUG *** " \ | |
2425 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2426 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2427 | ||
2428 | DEBUG(D_tls) | |
2429 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2430 | state->session, buff, len); | |
2431 | ||
2432 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2433 | if (inbytes > 0) return inbytes; |
2434 | if (inbytes == 0) | |
2435 | { | |
2436 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2437 | } | |
17c76198 | 2438 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2439 | |
2440 | return -1; | |
2441 | } | |
2442 | ||
2443 | ||
2444 | ||
17c76198 | 2445 | |
059ec3d9 PH |
2446 | /************************************************* |
2447 | * Write bytes down TLS channel * | |
2448 | *************************************************/ | |
2449 | ||
2450 | /* | |
2451 | Arguments: | |
817d9f57 | 2452 | is_server channel specifier |
059ec3d9 PH |
2453 | buff buffer of data |
2454 | len number of bytes | |
925ac8e4 | 2455 | more more data expected soon |
059ec3d9 PH |
2456 | |
2457 | Returns: the number of bytes after a successful write, | |
2458 | -1 after a failed write | |
2459 | */ | |
2460 | ||
2461 | int | |
925ac8e4 | 2462 | tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) |
059ec3d9 | 2463 | { |
17c76198 PP |
2464 | ssize_t outbytes; |
2465 | size_t left = len; | |
817d9f57 | 2466 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
925ac8e4 JH |
2467 | #ifdef SUPPORT_CORK |
2468 | static BOOL corked = FALSE; | |
2469 | ||
2470 | if (more && !corked) gnutls_record_cork(state->session); | |
2471 | #endif | |
2472 | ||
2473 | DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, | |
2474 | buff, left, more ? ", more" : ""); | |
059ec3d9 | 2475 | |
059ec3d9 PH |
2476 | while (left > 0) |
2477 | { | |
17c76198 PP |
2478 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2479 | buff, left); | |
2480 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2481 | |
17c76198 | 2482 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2483 | if (outbytes < 0) |
2484 | { | |
17c76198 | 2485 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2486 | return -1; |
2487 | } | |
2488 | if (outbytes == 0) | |
2489 | { | |
17c76198 | 2490 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2491 | return -1; |
2492 | } | |
2493 | ||
2494 | left -= outbytes; | |
2495 | buff += outbytes; | |
2496 | } | |
2497 | ||
17c76198 PP |
2498 | if (len > INT_MAX) |
2499 | { | |
2500 | DEBUG(D_tls) | |
2501 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2502 | len); | |
2503 | len = INT_MAX; | |
2504 | } | |
2505 | ||
925ac8e4 JH |
2506 | #ifdef SUPPORT_CORK |
2507 | if (more != corked) | |
2508 | { | |
2509 | if (!more) (void) gnutls_record_uncork(state->session, 0); | |
2510 | corked = more; | |
2511 | } | |
2512 | #endif | |
2513 | ||
17c76198 | 2514 | return (int) len; |
059ec3d9 PH |
2515 | } |
2516 | ||
2517 | ||
2518 | ||
17c76198 | 2519 | |
059ec3d9 | 2520 | /************************************************* |
17c76198 | 2521 | * Random number generation * |
059ec3d9 PH |
2522 | *************************************************/ |
2523 | ||
17c76198 PP |
2524 | /* Pseudo-random number generation. The result is not expected to be |
2525 | cryptographically strong but not so weak that someone will shoot themselves | |
2526 | in the foot using it as a nonce in input in some email header scheme or | |
2527 | whatever weirdness they'll twist this into. The result should handle fork() | |
2528 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2529 | |
17c76198 PP |
2530 | Arguments: |
2531 | max range maximum | |
2532 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2533 | */ |
2534 | ||
af3498d6 | 2535 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2536 | int |
2537 | vaguely_random_number(int max) | |
059ec3d9 | 2538 | { |
17c76198 PP |
2539 | unsigned int r; |
2540 | int i, needed_len; | |
2541 | uschar *p; | |
2542 | uschar smallbuf[sizeof(r)]; | |
2543 | ||
2544 | if (max <= 1) | |
2545 | return 0; | |
2546 | ||
2547 | needed_len = sizeof(r); | |
2548 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2549 | * asked for a number less than 10. */ | |
2550 | for (r = max, i = 0; r; ++i) | |
2551 | r >>= 1; | |
2552 | i = (i + 7) / 8; | |
2553 | if (i < needed_len) | |
2554 | needed_len = i; | |
2555 | ||
2556 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2557 | if (i < 0) | |
059ec3d9 | 2558 | { |
17c76198 PP |
2559 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2560 | return vaguely_random_number_fallback(max); | |
2561 | } | |
2562 | r = 0; | |
2563 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2564 | { | |
2565 | r *= 256; | |
2566 | r += *p; | |
059ec3d9 PH |
2567 | } |
2568 | ||
17c76198 PP |
2569 | /* We don't particularly care about weighted results; if someone wants |
2570 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2571 | return r % max; | |
059ec3d9 | 2572 | } |
af3498d6 PP |
2573 | #else /* HAVE_GNUTLS_RND */ |
2574 | int | |
2575 | vaguely_random_number(int max) | |
2576 | { | |
2577 | return vaguely_random_number_fallback(max); | |
2578 | } | |
2579 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2580 | |
36f12725 NM |
2581 | |
2582 | ||
2583 | ||
3375e053 PP |
2584 | /************************************************* |
2585 | * Let tls_require_ciphers be checked at startup * | |
2586 | *************************************************/ | |
2587 | ||
2588 | /* The tls_require_ciphers option, if set, must be something which the | |
2589 | library can parse. | |
2590 | ||
2591 | Returns: NULL on success, or error message | |
2592 | */ | |
2593 | ||
2594 | uschar * | |
2595 | tls_validate_require_cipher(void) | |
2596 | { | |
2597 | int rc; | |
2598 | uschar *expciphers = NULL; | |
2599 | gnutls_priority_t priority_cache; | |
2600 | const char *errpos; | |
cf0c6164 | 2601 | uschar * dummy_errstr; |
3375e053 PP |
2602 | |
2603 | #define validate_check_rc(Label) do { \ | |
2604 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2605 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2606 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2607 | ||
2608 | if (exim_gnutls_base_init_done) | |
2609 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2610 | "already initialised GnuTLS, Exim developer bug"); | |
2611 | ||
a5f239e4 | 2612 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2613 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2614 | { |
2615 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2616 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2617 | } | |
2618 | #endif | |
3375e053 PP |
2619 | rc = gnutls_global_init(); |
2620 | validate_check_rc(US"gnutls_global_init()"); | |
2621 | exim_gnutls_base_init_done = TRUE; | |
2622 | ||
2623 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2624 | return_deinit(NULL); | |
2625 | ||
cf0c6164 JH |
2626 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, |
2627 | &dummy_errstr)) | |
3375e053 PP |
2628 | return_deinit(US"failed to expand tls_require_ciphers"); |
2629 | ||
2630 | if (!(expciphers && *expciphers)) | |
2631 | return_deinit(NULL); | |
2632 | ||
2633 | DEBUG(D_tls) | |
2634 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2635 | ||
2636 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2637 | validate_check_rc(string_sprintf( | |
2638 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2639 | expciphers, errpos - CS expciphers, errpos)); | |
2640 | ||
2641 | #undef return_deinit | |
2642 | #undef validate_check_rc | |
2643 | gnutls_global_deinit(); | |
2644 | ||
2645 | return NULL; | |
2646 | } | |
2647 | ||
2648 | ||
2649 | ||
2650 | ||
36f12725 NM |
2651 | /************************************************* |
2652 | * Report the library versions. * | |
2653 | *************************************************/ | |
2654 | ||
2655 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2656 | ||
2657 | Arguments: a FILE* to print the results to | |
2658 | Returns: nothing | |
2659 | */ | |
2660 | ||
2661 | void | |
2662 | tls_version_report(FILE *f) | |
2663 | { | |
754a0503 PP |
2664 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2665 | " Runtime: %s\n", | |
2666 | LIBGNUTLS_VERSION, | |
2667 | gnutls_check_version(NULL)); | |
36f12725 NM |
2668 | } |
2669 | ||
2b4a568d JH |
2670 | /* vi: aw ai sw=2 |
2671 | */ | |
059ec3d9 | 2672 | /* End of tls-gnu.c */ |