Commit | Line | Data |
---|---|---|
059ec3d9 PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
5a66c31b | 5 | /* Copyright (c) University of Cambridge 1995 - 2014 */ |
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 | |
16 | Mavroyanopoulos. The revamp is partially a rewrite, partially cut&paste as | |
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> | |
45 | #endif | |
2b4a568d JH |
46 | #ifdef EXPERIMENTAL_OCSP |
47 | # include <gnutls/ocsp.h> | |
48 | #endif | |
059ec3d9 | 49 | |
17c76198 | 50 | /* GnuTLS 2 vs 3 |
059ec3d9 | 51 | |
17c76198 PP |
52 | GnuTLS 3 only: |
53 | gnutls_global_set_audit_log_function() | |
059ec3d9 | 54 | |
17c76198 PP |
55 | Changes: |
56 | gnutls_certificate_verify_peers2(): is new, drop the 2 for old version | |
57 | */ | |
059ec3d9 | 58 | |
17c76198 | 59 | /* Local static variables for GnuTLS */ |
059ec3d9 | 60 | |
17c76198 | 61 | /* Values for verify_requirement */ |
059ec3d9 | 62 | |
e51c7be2 JH |
63 | enum peer_verify_requirement |
64 | { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED | |
65 | #ifdef EXPERIMENTAL_CERTNAMES | |
66 | ,VERIFY_WITHHOST | |
67 | #endif | |
68 | }; | |
059ec3d9 | 69 | |
17c76198 PP |
70 | /* This holds most state for server or client; with this, we can set up an |
71 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
72 | over the TLS variables available for expansion. | |
059ec3d9 | 73 | |
17c76198 PP |
74 | Some of these correspond to variables in globals.c; those variables will |
75 | be set to point to content in one of these instances, as appropriate for | |
76 | the stage of the process lifetime. | |
059ec3d9 | 77 | |
389ca47a | 78 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 79 | */ |
059ec3d9 | 80 | |
17c76198 | 81 | typedef struct exim_gnutls_state { |
9d1c15ef | 82 | gnutls_session_t session; |
17c76198 | 83 | gnutls_certificate_credentials_t x509_cred; |
9d1c15ef | 84 | gnutls_priority_t priority_cache; |
17c76198 | 85 | enum peer_verify_requirement verify_requirement; |
9d1c15ef JH |
86 | int fd_in; |
87 | int fd_out; | |
88 | BOOL peer_cert_verified; | |
89 | BOOL trigger_sni_changes; | |
90 | BOOL have_set_peerdn; | |
17c76198 | 91 | const struct host_item *host; |
9d1c15ef JH |
92 | gnutls_x509_crt_t peercert; |
93 | uschar *peerdn; | |
94 | uschar *ciphersuite; | |
95 | uschar *received_sni; | |
17c76198 PP |
96 | |
97 | const uschar *tls_certificate; | |
98 | const uschar *tls_privatekey; | |
99 | const uschar *tls_sni; /* client send only, not received */ | |
100 | const uschar *tls_verify_certificates; | |
101 | const uschar *tls_crl; | |
102 | const uschar *tls_require_ciphers; | |
e51c7be2 | 103 | |
17c76198 PP |
104 | uschar *exp_tls_certificate; |
105 | uschar *exp_tls_privatekey; | |
106 | uschar *exp_tls_sni; | |
107 | uschar *exp_tls_verify_certificates; | |
108 | uschar *exp_tls_crl; | |
109 | uschar *exp_tls_require_ciphers; | |
44662487 | 110 | uschar *exp_tls_ocsp_file; |
e51c7be2 JH |
111 | #ifdef EXPERIMENTAL_CERTNAMES |
112 | uschar *exp_tls_verify_cert_hostnames; | |
113 | #endif | |
17c76198 | 114 | |
389ca47a | 115 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 116 | |
17c76198 PP |
117 | uschar *xfer_buffer; |
118 | int xfer_buffer_lwm; | |
119 | int xfer_buffer_hwm; | |
120 | int xfer_eof; | |
121 | int xfer_error; | |
17c76198 PP |
122 | } exim_gnutls_state_st; |
123 | ||
124 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 125 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 126 | NULL, NULL, NULL, NULL, |
17c76198 | 127 | NULL, NULL, NULL, NULL, NULL, NULL, |
44662487 | 128 | NULL, NULL, NULL, NULL, NULL, NULL, NULL, |
e51c7be2 JH |
129 | #ifdef EXPERIMENTAL_CERTNAMES |
130 | NULL, | |
131 | #endif | |
817d9f57 | 132 | NULL, |
17c76198 | 133 | NULL, 0, 0, 0, 0, |
17c76198 | 134 | }; |
83da1223 | 135 | |
17c76198 PP |
136 | /* Not only do we have our own APIs which don't pass around state, assuming |
137 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
138 | for callbacks, or as part of the session, so we have to keep a "this is the | |
139 | context we're currently dealing with" pointer and rely upon being | |
140 | single-threaded to keep from processing data on an inbound TLS connection while | |
141 | talking to another TLS connection for an outbound check. This does mean that | |
142 | there's no way for heart-beats to be responded to, for the duration of the | |
143 | second connection. */ | |
059ec3d9 | 144 | |
17c76198 | 145 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 146 | |
17c76198 PP |
147 | /* dh_params are initialised once within the lifetime of a process using TLS; |
148 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
149 | don't want to repeat this. */ | |
83da1223 | 150 | |
17c76198 | 151 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 152 | |
17c76198 | 153 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 154 | |
17c76198 | 155 | static const int ssl_session_timeout = 200; |
059ec3d9 | 156 | |
17c76198 | 157 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 158 | |
17c76198 | 159 | /* Guard library core initialisation */ |
83da1223 | 160 | |
17c76198 | 161 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 162 | |
059ec3d9 | 163 | |
17c76198 PP |
164 | /* ------------------------------------------------------------------------ */ |
165 | /* macros */ | |
83da1223 | 166 | |
17c76198 | 167 | #define MAX_HOST_LEN 255 |
83da1223 | 168 | |
17c76198 PP |
169 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
170 | the library logging; a value less than 0 disables the calls to set up logging | |
171 | callbacks. */ | |
2c17bb02 | 172 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
17c76198 | 173 | #define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 174 | #endif |
83da1223 | 175 | |
2c17bb02 | 176 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
bba74fc6 | 177 | #define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 178 | #endif |
83da1223 | 179 | |
af3498d6 PP |
180 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
181 | can ask for a bit-strength. Without that, we stick to the constant we had | |
182 | before, for now. */ | |
2c17bb02 | 183 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
af3498d6 | 184 | #define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 185 | #endif |
af3498d6 | 186 | |
17c76198 PP |
187 | #define exim_gnutls_err_check(Label) do { \ |
188 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 189 | |
17c76198 | 190 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 191 | |
17c76198 | 192 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
e51c7be2 JH |
193 | # define HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
194 | # define HAVE_GNUTLS_SEC_PARAM_CONSTANTS | |
195 | # define HAVE_GNUTLS_RND | |
2519e60d TL |
196 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
197 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
198 | * isn't available sometimes, so this needs to become a conditional | |
199 | * compilation; the sanest way to deal with this being a problem on | |
200 | * older OSes is to block it in the Local/Makefile with this compiler | |
201 | * definition */ | |
e51c7be2 JH |
202 | # ifndef AVOID_GNUTLS_PKCS11 |
203 | # define HAVE_GNUTLS_PKCS11 | |
204 | # endif /* AVOID_GNUTLS_PKCS11 */ | |
17c76198 | 205 | #endif |
83da1223 | 206 | |
af3498d6 PP |
207 | |
208 | ||
209 | ||
210 | /* ------------------------------------------------------------------------ */ | |
211 | /* Callback declarations */ | |
212 | ||
213 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
214 | static void exim_gnutls_logger_cb(int level, const char *message); | |
215 | #endif | |
216 | ||
217 | static int exim_sni_handling_cb(gnutls_session_t session); | |
218 | ||
44662487 JH |
219 | #ifdef EXPERIMENTAL_OCSP |
220 | static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
221 | gnutls_datum_t * ocsp_response); | |
222 | #endif | |
af3498d6 PP |
223 | |
224 | ||
225 | ||
17c76198 PP |
226 | /* ------------------------------------------------------------------------ */ |
227 | /* Static functions */ | |
059ec3d9 PH |
228 | |
229 | /************************************************* | |
230 | * Handle TLS error * | |
231 | *************************************************/ | |
232 | ||
233 | /* Called from lots of places when errors occur before actually starting to do | |
234 | the TLS handshake, that is, while the session is still in clear. Always returns | |
235 | DEFER for a server and FAIL for a client so that most calls can use "return | |
236 | tls_error(...)" to do this processing and then give an appropriate return. A | |
237 | single function is used for both server and client, because it is called from | |
238 | some shared functions. | |
239 | ||
240 | Argument: | |
241 | prefix text to include in the logged error | |
7199e1ee TF |
242 | msg additional error string (may be NULL) |
243 | usually obtained from gnutls_strerror() | |
17c76198 PP |
244 | host NULL if setting up a server; |
245 | the connected host if setting up a client | |
059ec3d9 PH |
246 | |
247 | Returns: OK/DEFER/FAIL | |
248 | */ | |
249 | ||
250 | static int | |
17c76198 | 251 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 252 | { |
17c76198 PP |
253 | if (host) |
254 | { | |
255 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", | |
256 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); | |
257 | return FAIL; | |
258 | } | |
259 | else | |
059ec3d9 | 260 | { |
7199e1ee | 261 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 262 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
263 | conn_info += 5; |
264 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", | |
17c76198 | 265 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
266 | return DEFER; |
267 | } | |
059ec3d9 PH |
268 | } |
269 | ||
270 | ||
271 | ||
17c76198 | 272 | |
059ec3d9 | 273 | /************************************************* |
17c76198 | 274 | * Deal with logging errors during I/O * |
059ec3d9 PH |
275 | *************************************************/ |
276 | ||
17c76198 | 277 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 278 | |
17c76198 PP |
279 | Argument: |
280 | state the current GnuTLS exim state container | |
281 | rc the GnuTLS error code, or 0 if it's a local error | |
282 | when text identifying read or write | |
283 | text local error text when ec is 0 | |
059ec3d9 | 284 | |
17c76198 | 285 | Returns: nothing |
059ec3d9 PH |
286 | */ |
287 | ||
17c76198 PP |
288 | static void |
289 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 290 | { |
17c76198 | 291 | const char *msg; |
059ec3d9 | 292 | |
17c76198 PP |
293 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
294 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
295 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
296 | else | |
297 | msg = gnutls_strerror(rc); | |
059ec3d9 | 298 | |
17c76198 PP |
299 | tls_error(when, msg, state->host); |
300 | } | |
059ec3d9 | 301 | |
059ec3d9 | 302 | |
059ec3d9 | 303 | |
059ec3d9 | 304 | |
17c76198 PP |
305 | /************************************************* |
306 | * Set various Exim expansion vars * | |
307 | *************************************************/ | |
059ec3d9 | 308 | |
e51c7be2 JH |
309 | #define exim_gnutls_cert_err(Label) \ |
310 | do \ | |
311 | { \ | |
312 | if (rc != GNUTLS_E_SUCCESS) \ | |
313 | { \ | |
314 | DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", \ | |
315 | (Label), gnutls_strerror(rc)); \ | |
316 | return rc; \ | |
317 | } \ | |
318 | } while (0) | |
9d1c15ef JH |
319 | |
320 | static int | |
321 | import_cert(const gnutls_datum * cert, gnutls_x509_crt_t * crtp) | |
322 | { | |
323 | int rc; | |
324 | ||
325 | rc = gnutls_x509_crt_init(crtp); | |
326 | exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); | |
327 | ||
328 | rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); | |
329 | exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); | |
330 | ||
331 | return rc; | |
332 | } | |
333 | ||
334 | #undef exim_gnutls_cert_err | |
335 | ||
336 | ||
17c76198 PP |
337 | /* We set various Exim global variables from the state, once a session has |
338 | been established. With TLS callouts, may need to change this to stack | |
339 | variables, or just re-call it with the server state after client callout | |
340 | has finished. | |
059ec3d9 | 341 | |
9d1c15ef | 342 | Make sure anything set here is unset in tls_getc(). |
17c76198 PP |
343 | |
344 | Sets: | |
345 | tls_active fd | |
346 | tls_bits strength indicator | |
347 | tls_certificate_verified bool indicator | |
348 | tls_channelbinding_b64 for some SASL mechanisms | |
349 | tls_cipher a string | |
9d1c15ef | 350 | tls_peercert pointer to library internal |
17c76198 PP |
351 | tls_peerdn a string |
352 | tls_sni a (UTF-8) string | |
9d1c15ef | 353 | tls_ourcert pointer to library internal |
17c76198 PP |
354 | |
355 | Argument: | |
356 | state the relevant exim_gnutls_state_st * | |
357 | */ | |
358 | ||
359 | static void | |
9d1c15ef | 360 | extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) |
17c76198 | 361 | { |
17c76198 | 362 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
363 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
364 | int old_pool; | |
365 | int rc; | |
366 | gnutls_datum_t channel; | |
367 | #endif | |
9d1c15ef | 368 | tls_support * tlsp = state->tlsp; |
17c76198 | 369 | |
9d1c15ef | 370 | tlsp->active = state->fd_out; |
17c76198 PP |
371 | |
372 | cipher = gnutls_cipher_get(state->session); | |
373 | /* returns size in "bytes" */ | |
9d1c15ef | 374 | tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 375 | |
9d1c15ef | 376 | tlsp->cipher = state->ciphersuite; |
17c76198 | 377 | |
817d9f57 | 378 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 379 | |
9d1c15ef | 380 | tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 381 | |
17c76198 PP |
382 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
383 | only available for use for authenticators while this TLS session is running. */ | |
384 | ||
385 | tls_channelbinding_b64 = NULL; | |
386 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
387 | channel.data = NULL; | |
388 | channel.size = 0; | |
389 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
390 | if (rc) { | |
391 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
392 | } else { | |
393 | old_pool = store_pool; | |
394 | store_pool = POOL_PERM; | |
395 | tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); | |
396 | store_pool = old_pool; | |
397 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
398 | } | |
399 | #endif | |
400 | ||
9d1c15ef JH |
401 | /* peercert is set in peer_status() */ |
402 | tlsp->peerdn = state->peerdn; | |
403 | tlsp->sni = state->received_sni; | |
404 | ||
405 | /* record our certificate */ | |
406 | { | |
407 | const gnutls_datum * cert = gnutls_certificate_get_ours(state->session); | |
408 | gnutls_x509_crt_t crt; | |
409 | ||
410 | tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; | |
411 | } | |
059ec3d9 PH |
412 | } |
413 | ||
414 | ||
415 | ||
17c76198 | 416 | |
059ec3d9 | 417 | /************************************************* |
575643cd | 418 | * Setup up DH parameters * |
059ec3d9 PH |
419 | *************************************************/ |
420 | ||
575643cd | 421 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
422 | be re-generated every so often, depending on security policy. What we do is to |
423 | keep these parameters in a file in the spool directory. If the file does not | |
424 | exist, we generate them. This means that it is easy to cause a regeneration. | |
425 | ||
426 | The new file is written as a temporary file and renamed, so that an incomplete | |
427 | file is never present. If two processes both compute some new parameters, you | |
428 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
429 | prevent this. | |
430 | ||
059ec3d9 PH |
431 | Returns: OK/DEFER/FAIL |
432 | */ | |
433 | ||
434 | static int | |
17c76198 | 435 | init_server_dh(void) |
059ec3d9 | 436 | { |
17c76198 PP |
437 | int fd, rc; |
438 | unsigned int dh_bits; | |
b5aea5e1 | 439 | gnutls_datum m; |
a799883d PP |
440 | uschar filename_buf[PATH_MAX]; |
441 | uschar *filename = NULL; | |
17c76198 | 442 | size_t sz; |
a799883d PP |
443 | uschar *exp_tls_dhparam; |
444 | BOOL use_file_in_spool = FALSE; | |
445 | BOOL use_fixed_file = FALSE; | |
17c76198 | 446 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 447 | |
17c76198 | 448 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 449 | |
17c76198 PP |
450 | rc = gnutls_dh_params_init(&dh_server_params); |
451 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 452 | |
a799883d PP |
453 | m.data = NULL; |
454 | m.size = 0; | |
455 | ||
456 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
457 | return DEFER; | |
458 | ||
459 | if (!exp_tls_dhparam) | |
460 | { | |
461 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
462 | m.data = US std_dh_prime_default(); | |
463 | m.size = Ustrlen(m.data); | |
464 | } | |
465 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
466 | use_file_in_spool = TRUE; | |
467 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
468 | { | |
469 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
470 | return OK; | |
471 | } | |
472 | else if (exp_tls_dhparam[0] != '/') | |
473 | { | |
474 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
475 | if (m.data == NULL) | |
476 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
477 | m.size = Ustrlen(m.data); | |
478 | } | |
479 | else | |
480 | { | |
481 | use_fixed_file = TRUE; | |
482 | filename = exp_tls_dhparam; | |
483 | } | |
484 | ||
485 | if (m.data) | |
486 | { | |
487 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
488 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
489 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
490 | return OK; | |
491 | } | |
492 | ||
af3498d6 PP |
493 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
494 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
495 | different filename and ensure we have sufficient bits. */ |
496 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
497 | if (!dh_bits) | |
498 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 499 | DEBUG(D_tls) |
b34fc30c | 500 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
501 | dh_bits); |
502 | #else | |
503 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
504 | DEBUG(D_tls) | |
505 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
506 | dh_bits); | |
507 | #endif | |
059ec3d9 | 508 | |
3375e053 PP |
509 | /* Some clients have hard-coded limits. */ |
510 | if (dh_bits > tls_dh_max_bits) | |
511 | { | |
512 | DEBUG(D_tls) | |
513 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
514 | tls_dh_max_bits); | |
515 | dh_bits = tls_dh_max_bits; | |
516 | } | |
517 | ||
a799883d PP |
518 | if (use_file_in_spool) |
519 | { | |
520 | if (!string_format(filename_buf, sizeof(filename_buf), | |
521 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
522 | return tls_error(US"overlong filename", NULL, NULL); | |
523 | filename = filename_buf; | |
524 | } | |
059ec3d9 | 525 | |
b5aea5e1 | 526 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 527 | parameters. */ |
059ec3d9 PH |
528 | |
529 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 530 | if (fd >= 0) |
059ec3d9 | 531 | { |
b5aea5e1 | 532 | struct stat statbuf; |
17c76198 PP |
533 | FILE *fp; |
534 | int saved_errno; | |
535 | ||
536 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
537 | { | |
538 | saved_errno = errno; | |
539 | (void)close(fd); | |
540 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
541 | } | |
542 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
543 | { |
544 | (void)close(fd); | |
17c76198 PP |
545 | return tls_error(US"TLS cache not a file", NULL, NULL); |
546 | } | |
547 | fp = fdopen(fd, "rb"); | |
548 | if (!fp) | |
549 | { | |
550 | saved_errno = errno; | |
551 | (void)close(fd); | |
552 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
553 | strerror(saved_errno), NULL); | |
b5aea5e1 | 554 | } |
059ec3d9 | 555 | |
b5aea5e1 PH |
556 | m.size = statbuf.st_size; |
557 | m.data = malloc(m.size); | |
558 | if (m.data == NULL) | |
17c76198 PP |
559 | { |
560 | fclose(fp); | |
561 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
562 | } | |
563 | sz = fread(m.data, m.size, 1, fp); | |
564 | if (!sz) | |
565 | { | |
566 | saved_errno = errno; | |
567 | fclose(fp); | |
568 | free(m.data); | |
569 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
570 | } | |
571 | fclose(fp); | |
b5aea5e1 | 572 | |
17c76198 | 573 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 574 | free(m.data); |
17c76198 PP |
575 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
576 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
577 | } |
578 | ||
579 | /* If the file does not exist, fall through to compute new data and cache it. | |
580 | If there was any other opening error, it is serious. */ | |
581 | ||
182ad5cf PH |
582 | else if (errno == ENOENT) |
583 | { | |
17c76198 | 584 | rc = -1; |
182ad5cf | 585 | DEBUG(D_tls) |
17c76198 | 586 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
587 | } |
588 | else | |
17c76198 PP |
589 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
590 | NULL, NULL); | |
b5aea5e1 PH |
591 | |
592 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
593 | is not useful. One particular case of this is when upgrading from an older | |
594 | release of Exim in which the data was stored in a different format. We don't | |
595 | try to be clever and support both formats; we just regenerate new data in this | |
596 | case. */ | |
597 | ||
17c76198 | 598 | if (rc < 0) |
b5aea5e1 | 599 | { |
17c76198 | 600 | uschar *temp_fn; |
201f5254 | 601 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 602 | |
17c76198 PP |
603 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
604 | return tls_error(US"Filename too long to generate replacement", | |
605 | CS filename, NULL); | |
059ec3d9 | 606 | |
17c76198 PP |
607 | temp_fn = string_copy(US "%s.XXXXXXX"); |
608 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 609 | if (fd < 0) |
17c76198 | 610 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
611 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
612 | ||
201f5254 PP |
613 | /* GnuTLS overshoots! |
614 | * If we ask for 2236, we might get 2237 or more. | |
615 | * But there's no way to ask GnuTLS how many bits there really are. | |
616 | * We can ask how many bits were used in a TLS session, but that's it! | |
617 | * The prime itself is hidden behind too much abstraction. | |
618 | * So we ask for less, and proceed on a wing and a prayer. | |
619 | * First attempt, subtracted 3 for 2233 and got 2240. | |
620 | */ | |
cae6e576 | 621 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
622 | { |
623 | dh_bits_gen = dh_bits - 10; | |
624 | DEBUG(D_tls) | |
625 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
626 | dh_bits_gen); | |
627 | } | |
628 | ||
629 | DEBUG(D_tls) | |
630 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
631 | dh_bits_gen); | |
632 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
633 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
634 | ||
635 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
636 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
637 | sample apps handle this. */ | |
638 | ||
639 | sz = 0; | |
640 | m.data = NULL; | |
641 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
642 | m.data, &sz); | |
643 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
644 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
645 | m.size = sz; | |
b5aea5e1 PH |
646 | m.data = malloc(m.size); |
647 | if (m.data == NULL) | |
17c76198 | 648 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
1f00591e | 649 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 650 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 651 | m.data, &sz); |
17c76198 PP |
652 | if (rc != GNUTLS_E_SUCCESS) |
653 | { | |
654 | free(m.data); | |
655 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
656 | } | |
1f00591e | 657 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 658 | |
17c76198 PP |
659 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
660 | if (sz != m.size) | |
661 | { | |
662 | free(m.data); | |
663 | return tls_error(US"TLS cache write D-H params failed", | |
664 | strerror(errno), NULL); | |
665 | } | |
b5aea5e1 | 666 | free(m.data); |
17c76198 PP |
667 | sz = write_to_fd_buf(fd, US"\n", 1); |
668 | if (sz != 1) | |
669 | return tls_error(US"TLS cache write D-H params final newline failed", | |
670 | strerror(errno), NULL); | |
671 | ||
672 | rc = close(fd); | |
673 | if (rc) | |
674 | return tls_error(US"TLS cache write close() failed", | |
675 | strerror(errno), NULL); | |
059ec3d9 | 676 | |
17c76198 PP |
677 | if (Urename(temp_fn, filename) < 0) |
678 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
679 | temp_fn, filename), strerror(errno), NULL); | |
059ec3d9 | 680 | |
17c76198 | 681 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
682 | } |
683 | ||
17c76198 | 684 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
685 | return OK; |
686 | } | |
687 | ||
688 | ||
689 | ||
690 | ||
691 | /************************************************* | |
17c76198 | 692 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
693 | *************************************************/ |
694 | ||
17c76198 PP |
695 | /* Called from both server and client code, via tls_init(), and also from |
696 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
697 | ||
698 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
699 | ||
700 | The callback should not call us unless state->trigger_sni_changes is true, | |
701 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
702 | |
703 | Arguments: | |
17c76198 | 704 | state exim_gnutls_state_st * |
059ec3d9 PH |
705 | |
706 | Returns: OK/DEFER/FAIL | |
707 | */ | |
708 | ||
709 | static int | |
17c76198 | 710 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 711 | { |
1365611d | 712 | struct stat statbuf; |
059ec3d9 | 713 | int rc; |
17c76198 PP |
714 | const host_item *host = state->host; /* macro should be reconsidered? */ |
715 | uschar *saved_tls_certificate = NULL; | |
716 | uschar *saved_tls_privatekey = NULL; | |
717 | uschar *saved_tls_verify_certificates = NULL; | |
718 | uschar *saved_tls_crl = NULL; | |
719 | int cert_count; | |
720 | ||
721 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 722 | if (!host) /* server */ |
17c76198 PP |
723 | { |
724 | if (!state->received_sni) | |
725 | { | |
d9b2312b JH |
726 | if (state->tls_certificate && |
727 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
728 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
729 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
730 | )) | |
17c76198 PP |
731 | { |
732 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
733 | state->trigger_sni_changes = TRUE; | |
734 | } | |
735 | } | |
736 | else | |
737 | { | |
1365611d | 738 | /* useful for debugging */ |
17c76198 PP |
739 | saved_tls_certificate = state->exp_tls_certificate; |
740 | saved_tls_privatekey = state->exp_tls_privatekey; | |
741 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
742 | saved_tls_crl = state->exp_tls_crl; | |
743 | } | |
744 | } | |
059ec3d9 | 745 | |
1365611d PP |
746 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
747 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
748 | ||
17c76198 PP |
749 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
750 | state members, assuming consistent naming; and expand_check() returns | |
751 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 752 | |
17c76198 PP |
753 | /* check if we at least have a certificate, before doing expensive |
754 | D-H generation. */ | |
059ec3d9 | 755 | |
17c76198 PP |
756 | if (!expand_check_tlsvar(tls_certificate)) |
757 | return DEFER; | |
059ec3d9 | 758 | |
17c76198 | 759 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 760 | |
17c76198 PP |
761 | if ((state->exp_tls_certificate == NULL) || |
762 | (*state->exp_tls_certificate == '\0')) | |
763 | { | |
2b4a568d | 764 | if (!host) |
17c76198 PP |
765 | return tls_error(US"no TLS server certificate is specified", NULL, NULL); |
766 | else | |
767 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
768 | } | |
059ec3d9 | 769 | |
17c76198 | 770 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
771 | return DEFER; |
772 | ||
17c76198 PP |
773 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
774 | ||
775 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 776 | { |
17c76198 PP |
777 | state->tls_privatekey = state->tls_certificate; |
778 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 779 | } |
c91535f3 | 780 | |
059ec3d9 | 781 | |
17c76198 | 782 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
783 | { |
784 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
785 | state->exp_tls_certificate, state->exp_tls_privatekey); |
786 | ||
787 | if (state->received_sni) | |
de365ded | 788 | { |
17c76198 PP |
789 | if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && |
790 | (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) | |
791 | { | |
b34fc30c | 792 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
793 | } |
794 | else | |
795 | { | |
b34fc30c | 796 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 797 | } |
8e669ac1 | 798 | } |
059ec3d9 | 799 | |
1365611d PP |
800 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
801 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
802 | GNUTLS_X509_FMT_PEM); | |
803 | exim_gnutls_err_check( | |
804 | string_sprintf("cert/key setup: cert=%s key=%s", | |
805 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
806 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 807 | } /* tls_certificate */ |
059ec3d9 | 808 | |
2b4a568d JH |
809 | |
810 | /* Set the OCSP stapling server info */ | |
811 | ||
812 | #ifdef EXPERIMENTAL_OCSP | |
813 | if ( !host /* server */ | |
814 | && tls_ocsp_file | |
815 | ) | |
816 | { | |
44662487 JH |
817 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", |
818 | &state->exp_tls_ocsp_file)) | |
2b4a568d JH |
819 | return DEFER; |
820 | ||
44662487 JH |
821 | /* Use the full callback method for stapling just to get observability. |
822 | More efficient would be to read the file once only, if it never changed | |
823 | (due to SNI). Would need restart on file update, or watch datestamp. */ | |
824 | ||
825 | gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, | |
826 | server_ocsp_stapling_cb, state->exp_tls_ocsp_file); | |
2b4a568d | 827 | |
44662487 | 828 | DEBUG(D_tls) debug_printf("Set OCSP response file %s\n", &state->exp_tls_ocsp_file); |
2b4a568d JH |
829 | } |
830 | #endif | |
831 | ||
832 | ||
059ec3d9 PH |
833 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
834 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
835 | error message is provided. However, if we just refrain from setting anything up | |
836 | in that case, certificate verification fails, which seems to be the correct | |
837 | behaviour. */ | |
838 | ||
17c76198 | 839 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 840 | { |
17c76198 | 841 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 842 | return DEFER; |
17c76198 PP |
843 | if (state->tls_crl && *state->tls_crl) |
844 | if (!expand_check_tlsvar(tls_crl)) | |
845 | return DEFER; | |
059ec3d9 | 846 | |
1365611d PP |
847 | if (!(state->exp_tls_verify_certificates && |
848 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
849 | { |
850 | DEBUG(D_tls) | |
1365611d PP |
851 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
852 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 853 | return OK; |
b34fc30c | 854 | } |
1365611d | 855 | } |
83e2f8a2 PP |
856 | else |
857 | { | |
858 | DEBUG(D_tls) | |
859 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
860 | return OK; | |
861 | } | |
17c76198 | 862 | |
1365611d PP |
863 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
864 | { | |
865 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
866 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
867 | strerror(errno)); | |
868 | return DEFER; | |
869 | } | |
17c76198 | 870 | |
619b2b25 PP |
871 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
872 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
873 | other weirdness. The thing we really want to check is that it's not a | |
874 | directory, since while OpenSSL supports that, GnuTLS does not. | |
875 | So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ | |
876 | if (S_ISDIR(statbuf.st_mode)) | |
1365611d PP |
877 | { |
878 | DEBUG(D_tls) | |
619b2b25 PP |
879 | debug_printf("verify certificates path is a dir: \"%s\"\n", |
880 | state->exp_tls_verify_certificates); | |
1365611d | 881 | log_write(0, LOG_MAIN|LOG_PANIC, |
619b2b25 | 882 | "tls_verify_certificates \"%s\" is a directory", |
1365611d PP |
883 | state->exp_tls_verify_certificates); |
884 | return DEFER; | |
885 | } | |
059ec3d9 | 886 | |
1365611d PP |
887 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
888 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 889 | |
1365611d PP |
890 | if (statbuf.st_size == 0) |
891 | { | |
892 | DEBUG(D_tls) | |
893 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
894 | return OK; | |
895 | } | |
059ec3d9 | 896 | |
1365611d PP |
897 | cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, |
898 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
899 | if (cert_count < 0) | |
900 | { | |
901 | rc = cert_count; | |
902 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); | |
903 | } | |
904 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 905 | |
5c8cda3a PP |
906 | if (state->tls_crl && *state->tls_crl && |
907 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 908 | { |
5c8cda3a PP |
909 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
910 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
911 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
912 | if (cert_count < 0) | |
1365611d | 913 | { |
5c8cda3a | 914 | rc = cert_count; |
1365611d PP |
915 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
916 | } | |
5c8cda3a | 917 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 918 | } |
059ec3d9 | 919 | |
059ec3d9 PH |
920 | return OK; |
921 | } | |
922 | ||
923 | ||
924 | ||
925 | ||
1365611d PP |
926 | /************************************************* |
927 | * Set X.509 state variables * | |
928 | *************************************************/ | |
929 | ||
930 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
931 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
932 | structure. Which means various other non-re-expanded pieces of state | |
933 | need to be re-set in the new struct, so the setting logic is pulled | |
934 | out to this. | |
935 | ||
936 | Arguments: | |
937 | state exim_gnutls_state_st * | |
938 | ||
939 | Returns: OK/DEFER/FAIL | |
940 | */ | |
941 | ||
942 | static int | |
943 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
944 | { | |
945 | int rc; | |
946 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
947 | ||
948 | /* Create D-H parameters, or read them from the cache file. This function does | |
949 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
950 | client-side params. */ | |
951 | ||
952 | if (!state->host) | |
953 | { | |
954 | if (!dh_server_params) | |
955 | { | |
956 | rc = init_server_dh(); | |
957 | if (rc != OK) return rc; | |
958 | } | |
959 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
960 | } | |
961 | ||
962 | /* Link the credentials to the session. */ | |
963 | ||
964 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
965 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
966 | ||
967 | return OK; | |
968 | } | |
969 | ||
059ec3d9 | 970 | /************************************************* |
17c76198 | 971 | * Initialize for GnuTLS * |
059ec3d9 PH |
972 | *************************************************/ |
973 | ||
17c76198 PP |
974 | /* Called from both server and client code. In the case of a server, errors |
975 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
976 | |
977 | Arguments: | |
17c76198 PP |
978 | host connected host, if client; NULL if server |
979 | certificate certificate file | |
980 | privatekey private key file | |
981 | sni TLS SNI to send, sometimes when client; else NULL | |
982 | cas CA certs file | |
983 | crl CRL file | |
984 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 985 | caller_state returned state-info structure |
059ec3d9 | 986 | |
17c76198 | 987 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
988 | */ |
989 | ||
17c76198 PP |
990 | static int |
991 | tls_init( | |
992 | const host_item *host, | |
993 | const uschar *certificate, | |
994 | const uschar *privatekey, | |
995 | const uschar *sni, | |
996 | const uschar *cas, | |
997 | const uschar *crl, | |
998 | const uschar *require_ciphers, | |
999 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 1000 | { |
17c76198 PP |
1001 | exim_gnutls_state_st *state; |
1002 | int rc; | |
1003 | size_t sz; | |
1004 | const char *errpos; | |
1005 | uschar *p; | |
1006 | BOOL want_default_priorities; | |
1007 | ||
1008 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 1009 | { |
17c76198 PP |
1010 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
1011 | ||
a5f239e4 PP |
1012 | #ifdef HAVE_GNUTLS_PKCS11 |
1013 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
1014 | which loads modules from a config file, which sounds good and may be wanted | |
1015 | by some sysadmin, but also means in common configurations that GNOME keyring | |
1016 | environment variables are used and so breaks for users calling mailq. | |
1017 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 1018 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
1019 | { |
1020 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
1021 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
1022 | } | |
1023 | #endif | |
1024 | ||
17c76198 PP |
1025 | rc = gnutls_global_init(); |
1026 | exim_gnutls_err_check(US"gnutls_global_init"); | |
1027 | ||
1028 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
1029 | DEBUG(D_tls) | |
059ec3d9 | 1030 | { |
17c76198 PP |
1031 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
1032 | /* arbitrarily chosen level; bump upto 9 for more */ | |
1033 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 1034 | } |
17c76198 PP |
1035 | #endif |
1036 | ||
1037 | exim_gnutls_base_init_done = TRUE; | |
059ec3d9 | 1038 | } |
059ec3d9 | 1039 | |
17c76198 PP |
1040 | if (host) |
1041 | { | |
1042 | state = &state_client; | |
1043 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1044 | state->tlsp = &tls_out; |
17c76198 PP |
1045 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
1046 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
1047 | } | |
1048 | else | |
1049 | { | |
1050 | state = &state_server; | |
1051 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 1052 | state->tlsp = &tls_in; |
17c76198 PP |
1053 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
1054 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
1055 | } | |
1056 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 1057 | |
17c76198 | 1058 | state->host = host; |
059ec3d9 | 1059 | |
17c76198 PP |
1060 | state->tls_certificate = certificate; |
1061 | state->tls_privatekey = privatekey; | |
5779e6aa | 1062 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1063 | state->tls_sni = sni; |
1064 | state->tls_verify_certificates = cas; | |
1065 | state->tls_crl = crl; | |
059ec3d9 | 1066 | |
17c76198 PP |
1067 | /* This handles the variables that might get re-expanded after TLS SNI; |
1068 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1069 | |
17c76198 PP |
1070 | DEBUG(D_tls) |
1071 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
1072 | rc = tls_expand_session_files(state); | |
1073 | if (rc != OK) return rc; | |
059ec3d9 | 1074 | |
1365611d PP |
1075 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1076 | requires a new structure afterwards. */ | |
83da1223 | 1077 | |
1365611d PP |
1078 | rc = tls_set_remaining_x509(state); |
1079 | if (rc != OK) return rc; | |
83da1223 | 1080 | |
17c76198 PP |
1081 | /* set SNI in client, only */ |
1082 | if (host) | |
1083 | { | |
a5f239e4 | 1084 | if (!expand_check(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni)) |
17c76198 PP |
1085 | return DEFER; |
1086 | if (state->exp_tls_sni && *state->exp_tls_sni) | |
1087 | { | |
1088 | DEBUG(D_tls) | |
1089 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); | |
1090 | sz = Ustrlen(state->exp_tls_sni); | |
1091 | rc = gnutls_server_name_set(state->session, | |
1092 | GNUTLS_NAME_DNS, state->exp_tls_sni, sz); | |
1093 | exim_gnutls_err_check(US"gnutls_server_name_set"); | |
1094 | } | |
1095 | } | |
1096 | else if (state->tls_sni) | |
1097 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1098 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1099 | |
17c76198 | 1100 | /* This is the priority string support, |
42bfef1e | 1101 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1102 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1103 | This was backwards incompatible, but means Exim no longer needs to track | |
1104 | all algorithms and provide string forms for them. */ | |
83da1223 | 1105 | |
17c76198 | 1106 | want_default_priorities = TRUE; |
83da1223 | 1107 | |
17c76198 | 1108 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1109 | { |
17c76198 PP |
1110 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1111 | return DEFER; | |
1112 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1113 | { |
17c76198 PP |
1114 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1115 | state->exp_tls_require_ciphers); | |
1116 | ||
1117 | rc = gnutls_priority_init(&state->priority_cache, | |
1118 | CS state->exp_tls_require_ciphers, &errpos); | |
1119 | want_default_priorities = FALSE; | |
1120 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1121 | } |
1122 | } | |
17c76198 PP |
1123 | if (want_default_priorities) |
1124 | { | |
83e2f8a2 PP |
1125 | DEBUG(D_tls) |
1126 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1127 | exim_default_gnutls_priority); | |
17c76198 PP |
1128 | rc = gnutls_priority_init(&state->priority_cache, |
1129 | exim_default_gnutls_priority, &errpos); | |
1130 | p = US exim_default_gnutls_priority; | |
1131 | } | |
83da1223 | 1132 | |
17c76198 PP |
1133 | exim_gnutls_err_check(string_sprintf( |
1134 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1135 | p, errpos - CS p, errpos)); | |
1136 | ||
1137 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1138 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1139 | ||
1140 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1141 | ||
1142 | /* Reduce security in favour of increased compatibility, if the admin | |
1143 | decides to make that trade-off. */ | |
1144 | if (gnutls_compat_mode) | |
83da1223 | 1145 | { |
17c76198 PP |
1146 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1147 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1148 | gnutls_session_enable_compatibility_mode(state->session); | |
1149 | #else | |
1150 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1151 | #endif | |
83da1223 PH |
1152 | } |
1153 | ||
17c76198 | 1154 | *caller_state = state; |
17c76198 | 1155 | return OK; |
83da1223 PH |
1156 | } |
1157 | ||
1158 | ||
1159 | ||
059ec3d9 | 1160 | /************************************************* |
17c76198 | 1161 | * Extract peer information * |
059ec3d9 PH |
1162 | *************************************************/ |
1163 | ||
17c76198 | 1164 | /* Called from both server and client code. |
4fe99a6c PP |
1165 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1166 | and we use that to detect double-calls. | |
059ec3d9 | 1167 | |
75fe387d PP |
1168 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1169 | for logging in the server side, but for the client side, we log after teardown | |
1170 | in src/deliver.c. While the session is up, we can twist about states and | |
1171 | repoint tls_* globals, but those variables used for logging or other variable | |
1172 | expansion that happens _after_ delivery need to have a longer life-time. | |
1173 | ||
1174 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1175 | doing this more than once per generation of a state context. We set them in | |
1176 | the state context, and repoint tls_* to them. After the state goes away, the | |
1177 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1178 | ||
1179 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1180 | don't apply. | |
1181 | ||
059ec3d9 | 1182 | Arguments: |
17c76198 | 1183 | state exim_gnutls_state_st * |
059ec3d9 | 1184 | |
17c76198 | 1185 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1186 | */ |
1187 | ||
17c76198 PP |
1188 | static int |
1189 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1190 | { |
75fe387d | 1191 | uschar cipherbuf[256]; |
17c76198 | 1192 | const gnutls_datum *cert_list; |
75fe387d | 1193 | int old_pool, rc; |
17c76198 | 1194 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1195 | gnutls_protocol_t protocol; |
1196 | gnutls_cipher_algorithm_t cipher; | |
1197 | gnutls_kx_algorithm_t kx; | |
1198 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1199 | gnutls_certificate_type_t ct; |
1200 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1201 | uschar *p, *dn_buf; |
17c76198 | 1202 | size_t sz; |
059ec3d9 | 1203 | |
4fe99a6c | 1204 | if (state->have_set_peerdn) |
17c76198 | 1205 | return OK; |
4fe99a6c | 1206 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1207 | |
4fe99a6c | 1208 | state->peerdn = NULL; |
059ec3d9 | 1209 | |
4fe99a6c PP |
1210 | /* tls_cipher */ |
1211 | cipher = gnutls_cipher_get(state->session); | |
1212 | protocol = gnutls_protocol_get_version(state->session); | |
1213 | mac = gnutls_mac_get(state->session); | |
1214 | kx = gnutls_kx_get(state->session); | |
1215 | ||
75fe387d | 1216 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1217 | "%s:%s:%d", |
1218 | gnutls_protocol_get_name(protocol), | |
1219 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1220 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1221 | ||
1222 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1223 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1224 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1225 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1226 | if (isspace(*p)) |
1227 | *p = '-'; | |
75fe387d PP |
1228 | old_pool = store_pool; |
1229 | store_pool = POOL_PERM; | |
1230 | state->ciphersuite = string_copy(cipherbuf); | |
1231 | store_pool = old_pool; | |
817d9f57 | 1232 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1233 | |
1234 | /* tls_peerdn */ | |
17c76198 | 1235 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1236 | |
17c76198 PP |
1237 | if (cert_list == NULL || cert_list_size == 0) |
1238 | { | |
17c76198 PP |
1239 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1240 | cert_list, cert_list_size); | |
e51c7be2 | 1241 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1242 | return tls_error(US"certificate verification failed", |
1243 | "no certificate received from peer", state->host); | |
1244 | return OK; | |
1245 | } | |
059ec3d9 | 1246 | |
17c76198 PP |
1247 | ct = gnutls_certificate_type_get(state->session); |
1248 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1249 | { |
17c76198 | 1250 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1251 | DEBUG(D_tls) |
1252 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
e51c7be2 | 1253 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 PP |
1254 | return tls_error(US"certificate verification not possible, unhandled type", |
1255 | ctn, state->host); | |
1256 | return OK; | |
83da1223 | 1257 | } |
059ec3d9 | 1258 | |
e51c7be2 JH |
1259 | #define exim_gnutls_peer_err(Label) \ |
1260 | do { \ | |
1261 | if (rc != GNUTLS_E_SUCCESS) \ | |
1262 | { \ | |
1263 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ | |
1264 | (Label), gnutls_strerror(rc)); \ | |
1265 | if (state->verify_requirement >= VERIFY_REQUIRED) \ | |
1266 | return tls_error((Label), gnutls_strerror(rc), state->host); \ | |
1267 | return OK; \ | |
1268 | } \ | |
1269 | } while (0) | |
17c76198 | 1270 | |
9d1c15ef JH |
1271 | rc = import_cert(&cert_list[0], &crt); |
1272 | exim_gnutls_peer_err(US"cert 0"); | |
1273 | ||
1274 | state->tlsp->peercert = state->peercert = crt; | |
17c76198 | 1275 | |
17c76198 PP |
1276 | sz = 0; |
1277 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1278 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1279 | { |
17c76198 PP |
1280 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1281 | return FAIL; /* should not happen */ | |
059ec3d9 | 1282 | } |
17c76198 PP |
1283 | dn_buf = store_get_perm(sz); |
1284 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1285 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
9d1c15ef | 1286 | |
17c76198 PP |
1287 | state->peerdn = dn_buf; |
1288 | ||
1289 | return OK; | |
1290 | #undef exim_gnutls_peer_err | |
1291 | } | |
059ec3d9 | 1292 | |
059ec3d9 | 1293 | |
059ec3d9 | 1294 | |
059ec3d9 | 1295 | |
17c76198 PP |
1296 | /************************************************* |
1297 | * Verify peer certificate * | |
1298 | *************************************************/ | |
059ec3d9 | 1299 | |
17c76198 PP |
1300 | /* Called from both server and client code. |
1301 | *Should* be using a callback registered with | |
1302 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1303 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1304 | |
17c76198 PP |
1305 | Arguments: |
1306 | state exim_gnutls_state_st * | |
1307 | error where to put an error message | |
059ec3d9 | 1308 | |
17c76198 PP |
1309 | Returns: |
1310 | FALSE if the session should be rejected | |
1311 | TRUE if the cert is okay or we just don't care | |
1312 | */ | |
059ec3d9 | 1313 | |
17c76198 PP |
1314 | static BOOL |
1315 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1316 | { | |
1317 | int rc; | |
1318 | unsigned int verify; | |
1319 | ||
1320 | *error = NULL; | |
1321 | ||
0a92f87f | 1322 | if ((rc = peer_status(state)) != OK) |
e6060e2c | 1323 | { |
17c76198 | 1324 | verify = GNUTLS_CERT_INVALID; |
0a92f87f | 1325 | *error = "certificate not supplied"; |
17c76198 PP |
1326 | } |
1327 | else | |
17c76198 | 1328 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1329 | |
17c76198 PP |
1330 | /* Handle the result of verification. INVALID seems to be set as well |
1331 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1332 | |
e51c7be2 JH |
1333 | if (rc < 0 || |
1334 | verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED) | |
1335 | ) | |
17c76198 PP |
1336 | { |
1337 | state->peer_cert_verified = FALSE; | |
0a92f87f JH |
1338 | if (!*error) |
1339 | *error = verify & GNUTLS_CERT_REVOKED | |
1340 | ? "certificate revoked" : "certificate invalid"; | |
059ec3d9 | 1341 | |
17c76198 | 1342 | DEBUG(D_tls) |
e51c7be2 | 1343 | debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", |
4fe99a6c | 1344 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1345 | |
e51c7be2 | 1346 | if (state->verify_requirement >= VERIFY_REQUIRED) |
17c76198 | 1347 | { |
e51c7be2 JH |
1348 | gnutls_alert_send(state->session, |
1349 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
17c76198 PP |
1350 | return FALSE; |
1351 | } | |
1352 | DEBUG(D_tls) | |
4789da3a | 1353 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 | 1354 | } |
e51c7be2 | 1355 | |
17c76198 PP |
1356 | else |
1357 | { | |
e51c7be2 JH |
1358 | #ifdef EXPERIMENTAL_CERTNAMES |
1359 | if (state->verify_requirement == VERIFY_WITHHOST) | |
1360 | { | |
1361 | int sep = 0; | |
1362 | uschar * list = state->exp_tls_verify_cert_hostnames; | |
1363 | uschar * name; | |
1364 | while (name = string_nextinlist(&list, &sep, NULL, 0)) | |
1365 | if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) | |
1366 | break; | |
1367 | if (!name) | |
1368 | { | |
1369 | DEBUG(D_tls) | |
1370 | debug_printf("TLS certificate verification failed: cert name mismatch\n"); | |
1371 | gnutls_alert_send(state->session, | |
1372 | GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1373 | return FALSE; | |
1374 | } | |
1375 | } | |
1376 | #endif | |
17c76198 | 1377 | state->peer_cert_verified = TRUE; |
e51c7be2 | 1378 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", |
4fe99a6c | 1379 | state->peerdn ? state->peerdn : US"<unset>"); |
17c76198 | 1380 | } |
059ec3d9 | 1381 | |
817d9f57 | 1382 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1383 | |
17c76198 PP |
1384 | return TRUE; |
1385 | } | |
059ec3d9 | 1386 | |
17c76198 PP |
1387 | |
1388 | ||
1389 | ||
1390 | /* ------------------------------------------------------------------------ */ | |
1391 | /* Callbacks */ | |
1392 | ||
1393 | /* Logging function which can be registered with | |
1394 | * gnutls_global_set_log_function() | |
1395 | * gnutls_global_set_log_level() 0..9 | |
1396 | */ | |
af3498d6 | 1397 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1398 | static void |
17c76198 | 1399 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1400 | { |
8c79eebf PP |
1401 | size_t len = strlen(message); |
1402 | if (len < 1) | |
1403 | { | |
1404 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1405 | return; | |
1406 | } | |
1407 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1408 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1409 | } |
af3498d6 | 1410 | #endif |
059ec3d9 | 1411 | |
059ec3d9 | 1412 | |
17c76198 PP |
1413 | /* Called after client hello, should handle SNI work. |
1414 | This will always set tls_sni (state->received_sni) if available, | |
1415 | and may trigger presenting different certificates, | |
1416 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1417 | |
17c76198 PP |
1418 | Should be registered with |
1419 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1420 | |
17c76198 PP |
1421 | "This callback must return 0 on success or a gnutls error code to terminate the |
1422 | handshake.". | |
059ec3d9 | 1423 | |
17c76198 PP |
1424 | For inability to get SNI information, we return 0. |
1425 | We only return non-zero if re-setup failed. | |
817d9f57 | 1426 | Only used for server-side TLS. |
17c76198 | 1427 | */ |
44bbabb5 | 1428 | |
17c76198 PP |
1429 | static int |
1430 | exim_sni_handling_cb(gnutls_session_t session) | |
1431 | { | |
1432 | char sni_name[MAX_HOST_LEN]; | |
1433 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1434 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1435 | unsigned int sni_type; |
1436 | int rc, old_pool; | |
1437 | ||
1438 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1439 | if (rc != GNUTLS_E_SUCCESS) |
1440 | { | |
1441 | DEBUG(D_tls) { | |
1442 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1443 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1444 | else | |
1445 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1446 | gnutls_strerror(rc), rc); | |
1447 | }; | |
1448 | return 0; | |
1449 | } | |
1450 | ||
17c76198 PP |
1451 | if (sni_type != GNUTLS_NAME_DNS) |
1452 | { | |
1453 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1454 | return 0; | |
1455 | } | |
44bbabb5 | 1456 | |
17c76198 PP |
1457 | /* We now have a UTF-8 string in sni_name */ |
1458 | old_pool = store_pool; | |
1459 | store_pool = POOL_PERM; | |
1460 | state->received_sni = string_copyn(US sni_name, data_len); | |
1461 | store_pool = old_pool; | |
1462 | ||
1463 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1464 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1465 | |
1466 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1467 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1468 | ||
1469 | if (!state->trigger_sni_changes) | |
1470 | return 0; | |
1471 | ||
1472 | rc = tls_expand_session_files(state); | |
1473 | if (rc != OK) | |
1474 | { | |
1475 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1476 | been offered. The best we can do now is abort. */ | |
1477 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1478 | } | |
1479 | ||
1365611d PP |
1480 | rc = tls_set_remaining_x509(state); |
1481 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1482 | ||
1483 | return 0; | |
059ec3d9 PH |
1484 | } |
1485 | ||
1486 | ||
1487 | ||
44662487 JH |
1488 | #ifdef EXPERIMENTAL_OCSP |
1489 | ||
1490 | static int | |
1491 | server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, | |
1492 | gnutls_datum_t * ocsp_response) | |
1493 | { | |
1494 | int ret; | |
1495 | ||
44662487 JH |
1496 | if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) |
1497 | { | |
1498 | DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", | |
1499 | (char *)ptr); | |
018058b2 | 1500 | tls_in.ocsp = OCSP_NOT_RESP; |
44662487 JH |
1501 | return GNUTLS_E_NO_CERTIFICATE_STATUS; |
1502 | } | |
1503 | ||
018058b2 | 1504 | tls_in.ocsp = OCSP_VFY_NOT_TRIED; |
44662487 JH |
1505 | return 0; |
1506 | } | |
1507 | ||
1508 | #endif | |
1509 | ||
1510 | ||
1511 | ||
1512 | ||
17c76198 PP |
1513 | |
1514 | /* ------------------------------------------------------------------------ */ | |
1515 | /* Exported functions */ | |
1516 | ||
1517 | ||
1518 | ||
1519 | ||
059ec3d9 PH |
1520 | /************************************************* |
1521 | * Start a TLS session in a server * | |
1522 | *************************************************/ | |
1523 | ||
1524 | /* This is called when Exim is running as a server, after having received | |
1525 | the STARTTLS command. It must respond to that command, and then negotiate | |
1526 | a TLS session. | |
1527 | ||
1528 | Arguments: | |
83da1223 | 1529 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1530 | |
1531 | Returns: OK on success | |
1532 | DEFER for errors before the start of the negotiation | |
1533 | FAIL for errors during the negotation; the server can't | |
1534 | continue running. | |
1535 | */ | |
1536 | ||
1537 | int | |
17c76198 | 1538 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1539 | { |
1540 | int rc; | |
7199e1ee | 1541 | const char *error; |
17c76198 | 1542 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1543 | |
1544 | /* Check for previous activation */ | |
817d9f57 | 1545 | if (tls_in.active >= 0) |
059ec3d9 | 1546 | { |
17c76198 | 1547 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1548 | smtp_printf("554 Already in TLS\r\n"); |
1549 | return FAIL; | |
1550 | } | |
1551 | ||
1552 | /* Initialize the library. If it fails, it will already have logged the error | |
1553 | and sent an SMTP response. */ | |
1554 | ||
17c76198 | 1555 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1556 | |
17c76198 PP |
1557 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1558 | NULL, tls_verify_certificates, tls_crl, | |
1559 | require_ciphers, &state); | |
059ec3d9 PH |
1560 | if (rc != OK) return rc; |
1561 | ||
059ec3d9 PH |
1562 | /* If this is a host for which certificate verification is mandatory or |
1563 | optional, set up appropriately. */ | |
1564 | ||
059ec3d9 | 1565 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 | 1566 | { |
e51c7be2 JH |
1567 | DEBUG(D_tls) |
1568 | debug_printf("TLS: a client certificate will be required.\n"); | |
17c76198 PP |
1569 | state->verify_requirement = VERIFY_REQUIRED; |
1570 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1571 | } | |
059ec3d9 | 1572 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 | 1573 | { |
e51c7be2 JH |
1574 | DEBUG(D_tls) |
1575 | debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
17c76198 PP |
1576 | state->verify_requirement = VERIFY_OPTIONAL; |
1577 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1578 | } | |
1579 | else | |
1580 | { | |
e51c7be2 JH |
1581 | DEBUG(D_tls) |
1582 | debug_printf("TLS: a client certificate will not be requested.\n"); | |
17c76198 PP |
1583 | state->verify_requirement = VERIFY_NONE; |
1584 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1585 | } | |
059ec3d9 | 1586 | |
17c76198 PP |
1587 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1588 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1589 | |
17c76198 PP |
1590 | gnutls_handshake_set_post_client_hello_function(state->session, |
1591 | exim_sni_handling_cb); | |
059ec3d9 PH |
1592 | |
1593 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1594 | on connection, where outputting anything now upsets the clients and tends to | |
1595 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1596 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1597 | mode, the fflush() happens when smtp_getc() is called. */ | |
1598 | ||
817d9f57 | 1599 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1600 | { |
1601 | smtp_printf("220 TLS go ahead\r\n"); | |
9d1c15ef | 1602 | fflush(smtp_out); |
059ec3d9 PH |
1603 | } |
1604 | ||
1605 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1606 | that the GnuTLS library doesn't. */ | |
1607 | ||
17c76198 | 1608 | gnutls_transport_set_ptr2(state->session, |
44662487 JH |
1609 | (gnutls_transport_ptr)(long) fileno(smtp_in), |
1610 | (gnutls_transport_ptr)(long) fileno(smtp_out)); | |
17c76198 PP |
1611 | state->fd_in = fileno(smtp_in); |
1612 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1613 | |
1614 | sigalrm_seen = FALSE; | |
1615 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 PP |
1616 | do |
1617 | { | |
1618 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1619 | } while ((rc == GNUTLS_E_AGAIN) || |
1620 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1621 | alarm(0); |
1622 | ||
17c76198 | 1623 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1624 | { |
17c76198 PP |
1625 | tls_error(US"gnutls_handshake", |
1626 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
059ec3d9 PH |
1627 | /* It seems that, except in the case of a timeout, we have to close the |
1628 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1629 | until the server times out. */ | |
1630 | ||
1631 | if (!sigalrm_seen) | |
1632 | { | |
f1e894f3 PH |
1633 | (void)fclose(smtp_out); |
1634 | (void)fclose(smtp_in); | |
059ec3d9 PH |
1635 | } |
1636 | ||
1637 | return FAIL; | |
1638 | } | |
1639 | ||
1640 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1641 | ||
17c76198 PP |
1642 | /* Verify after the fact */ |
1643 | ||
9d1c15ef JH |
1644 | if ( state->verify_requirement != VERIFY_NONE |
1645 | && !verify_certificate(state, &error)) | |
059ec3d9 | 1646 | { |
9d1c15ef | 1647 | if (state->verify_requirement != VERIFY_OPTIONAL) |
17c76198 | 1648 | { |
9d1c15ef JH |
1649 | tls_error(US"certificate verification failed", error, NULL); |
1650 | return FAIL; | |
17c76198 | 1651 | } |
9d1c15ef JH |
1652 | DEBUG(D_tls) |
1653 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1654 | error); | |
059ec3d9 PH |
1655 | } |
1656 | ||
17c76198 PP |
1657 | /* Figure out peer DN, and if authenticated, etc. */ |
1658 | ||
1659 | rc = peer_status(state); | |
1660 | if (rc != OK) return rc; | |
1661 | ||
1662 | /* Sets various Exim expansion variables; always safe within server */ | |
1663 | ||
9d1c15ef | 1664 | extract_exim_vars_from_tls_state(state); |
059ec3d9 PH |
1665 | |
1666 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1667 | and initialize appropriately. */ | |
1668 | ||
17c76198 | 1669 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1670 | |
1671 | receive_getc = tls_getc; | |
1672 | receive_ungetc = tls_ungetc; | |
1673 | receive_feof = tls_feof; | |
1674 | receive_ferror = tls_ferror; | |
58eb016e | 1675 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1676 | |
059ec3d9 PH |
1677 | return OK; |
1678 | } | |
1679 | ||
1680 | ||
1681 | ||
1682 | ||
1683 | /************************************************* | |
1684 | * Start a TLS session in a client * | |
1685 | *************************************************/ | |
1686 | ||
1687 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1688 | ||
1689 | Arguments: | |
1690 | fd the fd of the connection | |
1691 | host connected host (for messages) | |
83da1223 | 1692 | addr the first address (not used) |
65867078 | 1693 | ob smtp transport options |
059ec3d9 PH |
1694 | |
1695 | Returns: OK/DEFER/FAIL (because using common functions), | |
1696 | but for a client, DEFER and FAIL have the same meaning | |
1697 | */ | |
1698 | ||
1699 | int | |
17c76198 | 1700 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1701 | address_item *addr ARG_UNUSED, |
65867078 | 1702 | void *v_ob) |
059ec3d9 | 1703 | { |
65867078 | 1704 | smtp_transport_options_block *ob = v_ob; |
059ec3d9 | 1705 | int rc; |
17c76198 PP |
1706 | const char *error; |
1707 | exim_gnutls_state_st *state = NULL; | |
2b4a568d | 1708 | #ifdef EXPERIMENTAL_OCSP |
65867078 | 1709 | BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, |
2b4a568d | 1710 | NULL, host->name, host->address, NULL) == OK; |
44662487 JH |
1711 | BOOL request_ocsp = require_ocsp ? TRUE |
1712 | : verify_check_this_host(&ob->hosts_request_ocsp, | |
1713 | NULL, host->name, host->address, NULL) == OK; | |
2b4a568d | 1714 | #endif |
059ec3d9 | 1715 | |
17c76198 | 1716 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1717 | |
65867078 JH |
1718 | if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, |
1719 | ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, | |
1720 | ob->tls_require_ciphers, &state)) != OK) | |
2b4a568d | 1721 | return rc; |
059ec3d9 | 1722 | |
54c90be1 | 1723 | { |
65867078 JH |
1724 | int dh_min_bits = ob->tls_dh_min_bits; |
1725 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) | |
1726 | { | |
1727 | DEBUG(D_tls) | |
1728 | debug_printf("WARNING: tls_dh_min_bits far too low," | |
1729 | " clamping %d up to %d\n", | |
1730 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1731 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1732 | } | |
54c90be1 | 1733 | |
65867078 JH |
1734 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum" |
1735 | " acceptable bits to %d\n", | |
1736 | dh_min_bits); | |
1737 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
1738 | } | |
83da1223 | 1739 | |
2b4a568d JH |
1740 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
1741 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only | |
1742 | the specified host patterns if one of them is defined */ | |
1743 | ||
1744 | if (( state->exp_tls_verify_certificates | |
65867078 JH |
1745 | && !ob->tls_verify_hosts |
1746 | && !ob->tls_try_verify_hosts | |
2b4a568d JH |
1747 | ) |
1748 | || | |
65867078 | 1749 | verify_check_host(&ob->tls_verify_hosts) == OK |
2b4a568d | 1750 | ) |
17c76198 | 1751 | { |
e51c7be2 JH |
1752 | #ifdef EXPERIMENTAL_CERTNAMES |
1753 | if (ob->tls_verify_cert_hostnames) | |
1754 | { | |
1755 | DEBUG(D_tls) | |
1756 | debug_printf("TLS: server cert incl. hostname verification required.\n"); | |
1757 | state->verify_requirement = VERIFY_WITHHOST; | |
1758 | if (!expand_check(ob->tls_verify_cert_hostnames, | |
1759 | US"tls_verify_cert_hostnames", | |
1760 | &state->exp_tls_verify_cert_hostnames)) | |
1761 | return FAIL; | |
1762 | if (state->exp_tls_verify_cert_hostnames) | |
1763 | DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n", | |
1764 | state->exp_tls_verify_cert_hostnames); | |
1765 | } | |
1766 | else | |
1767 | #endif | |
1768 | { | |
1769 | DEBUG(D_tls) | |
1770 | debug_printf("TLS: server certificate verification required.\n"); | |
1771 | state->verify_requirement = VERIFY_REQUIRED; | |
1772 | } | |
52f93eed WB |
1773 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); |
1774 | } | |
65867078 | 1775 | else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) |
52f93eed | 1776 | { |
e51c7be2 JH |
1777 | DEBUG(D_tls) |
1778 | debug_printf("TLS: server certificate verification optional.\n"); | |
52f93eed | 1779 | state->verify_requirement = VERIFY_OPTIONAL; |
17c76198 PP |
1780 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
1781 | } | |
1782 | else | |
1783 | { | |
e51c7be2 JH |
1784 | DEBUG(D_tls) |
1785 | debug_printf("TLS: server certificate verification not required.\n"); | |
52f93eed WB |
1786 | state->verify_requirement = VERIFY_NONE; |
1787 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 1788 | } |
059ec3d9 | 1789 | |
2b4a568d | 1790 | #ifdef EXPERIMENTAL_OCSP /* since GnuTLS 3.1.3 */ |
44662487 | 1791 | if (request_ocsp) |
9d1c15ef JH |
1792 | { |
1793 | DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); | |
65867078 JH |
1794 | if ((rc = gnutls_ocsp_status_request_enable_client(state->session, |
1795 | NULL, 0, NULL)) != OK) | |
9d1c15ef JH |
1796 | return tls_error(US"cert-status-req", |
1797 | gnutls_strerror(rc), state->host); | |
44662487 | 1798 | tls_out.ocsp = OCSP_NOT_RESP; |
9d1c15ef | 1799 | } |
2b4a568d JH |
1800 | #endif |
1801 | ||
44662487 | 1802 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)(long) fd); |
17c76198 PP |
1803 | state->fd_in = fd; |
1804 | state->fd_out = fd; | |
059ec3d9 | 1805 | |
9d1c15ef | 1806 | DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); |
059ec3d9 PH |
1807 | /* There doesn't seem to be a built-in timeout on connection. */ |
1808 | ||
1809 | sigalrm_seen = FALSE; | |
65867078 | 1810 | alarm(ob->command_timeout); |
17c76198 PP |
1811 | do |
1812 | { | |
1813 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1814 | } while ((rc == GNUTLS_E_AGAIN) || |
1815 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1816 | alarm(0); |
1817 | ||
4fe99a6c PP |
1818 | if (rc != GNUTLS_E_SUCCESS) |
1819 | return tls_error(US"gnutls_handshake", | |
1820 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
1821 | ||
17c76198 | 1822 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 1823 | |
17c76198 | 1824 | /* Verify late */ |
059ec3d9 | 1825 | |
17c76198 PP |
1826 | if (state->verify_requirement != VERIFY_NONE && |
1827 | !verify_certificate(state, &error)) | |
1828 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 1829 | |
2b4a568d JH |
1830 | #ifdef EXPERIMENTAL_OCSP |
1831 | if (require_ocsp) | |
1832 | { | |
1833 | DEBUG(D_tls) | |
1834 | { | |
1835 | gnutls_datum_t stapling; | |
1836 | gnutls_ocsp_resp_t resp; | |
1837 | gnutls_datum_t printed; | |
1838 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
1839 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
1840 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
1841 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
1842 | ) | |
1843 | { | |
65867078 | 1844 | debug_printf("%.4096s", printed.data); |
2b4a568d JH |
1845 | gnutls_free(printed.data); |
1846 | } | |
1847 | else | |
1848 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); | |
1849 | } | |
1850 | ||
2b4a568d | 1851 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) |
018058b2 JH |
1852 | { |
1853 | tls_out.ocsp = OCSP_FAILED; | |
2b4a568d | 1854 | return tls_error(US"certificate status check failed", NULL, state->host); |
018058b2 | 1855 | } |
2b4a568d | 1856 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); |
44662487 | 1857 | tls_out.ocsp = OCSP_VFIED; |
2b4a568d JH |
1858 | } |
1859 | #endif | |
1860 | ||
17c76198 | 1861 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 1862 | |
2b4a568d JH |
1863 | if ((rc = peer_status(state)) != OK) |
1864 | return rc; | |
059ec3d9 | 1865 | |
4fe99a6c | 1866 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 1867 | |
9d1c15ef | 1868 | extract_exim_vars_from_tls_state(state); |
059ec3d9 | 1869 | |
059ec3d9 PH |
1870 | return OK; |
1871 | } | |
1872 | ||
1873 | ||
1874 | ||
17c76198 | 1875 | |
059ec3d9 | 1876 | /************************************************* |
17c76198 | 1877 | * Close down a TLS session * |
059ec3d9 PH |
1878 | *************************************************/ |
1879 | ||
17c76198 PP |
1880 | /* This is also called from within a delivery subprocess forked from the |
1881 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1882 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 1883 | |
17c76198 PP |
1884 | Arguments: TRUE if gnutls_bye is to be called |
1885 | Returns: nothing | |
059ec3d9 PH |
1886 | */ |
1887 | ||
17c76198 | 1888 | void |
817d9f57 | 1889 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1890 | { |
817d9f57 | 1891 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1892 | |
389ca47a | 1893 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
1894 | |
1895 | if (shutdown) | |
1896 | { | |
1897 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1898 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
1899 | } | |
1900 | ||
1901 | gnutls_deinit(state->session); | |
1902 | ||
389ca47a | 1903 | state->tlsp->active = -1; |
17c76198 PP |
1904 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
1905 | ||
1906 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
1907 | { | |
1908 | gnutls_global_deinit(); | |
1909 | exim_gnutls_base_init_done = FALSE; | |
1910 | } | |
7199e1ee | 1911 | |
059ec3d9 PH |
1912 | } |
1913 | ||
1914 | ||
1915 | ||
17c76198 | 1916 | |
059ec3d9 PH |
1917 | /************************************************* |
1918 | * TLS version of getc * | |
1919 | *************************************************/ | |
1920 | ||
1921 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1922 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 1923 | Only used by the server-side TLS. |
059ec3d9 | 1924 | |
17c76198 PP |
1925 | This feeds DKIM and should be used for all message-body reads. |
1926 | ||
059ec3d9 PH |
1927 | Arguments: none |
1928 | Returns: the next character or EOF | |
1929 | */ | |
1930 | ||
1931 | int | |
1932 | tls_getc(void) | |
1933 | { | |
817d9f57 | 1934 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 1935 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 1936 | { |
17c76198 | 1937 | ssize_t inbytes; |
059ec3d9 | 1938 | |
17c76198 PP |
1939 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
1940 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
1941 | |
1942 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1943 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
1944 | ssl_xfer_buffer_size); |
1945 | alarm(0); | |
1946 | ||
1947 | /* A zero-byte return appears to mean that the TLS session has been | |
1948 | closed down, not that the socket itself has been closed down. Revert to | |
1949 | non-TLS handling. */ | |
1950 | ||
1951 | if (inbytes == 0) | |
1952 | { | |
1953 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1954 | ||
1955 | receive_getc = smtp_getc; | |
1956 | receive_ungetc = smtp_ungetc; | |
1957 | receive_feof = smtp_feof; | |
1958 | receive_ferror = smtp_ferror; | |
58eb016e | 1959 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1960 | |
17c76198 PP |
1961 | gnutls_deinit(state->session); |
1962 | state->session = NULL; | |
817d9f57 JH |
1963 | state->tlsp->active = -1; |
1964 | state->tlsp->bits = 0; | |
1965 | state->tlsp->certificate_verified = FALSE; | |
9d1c15ef | 1966 | tls_channelbinding_b64 = NULL; |
817d9f57 | 1967 | state->tlsp->cipher = NULL; |
9d1c15ef | 1968 | state->tlsp->peercert = NULL; |
817d9f57 | 1969 | state->tlsp->peerdn = NULL; |
059ec3d9 PH |
1970 | |
1971 | return smtp_getc(); | |
1972 | } | |
1973 | ||
1974 | /* Handle genuine errors */ | |
1975 | ||
1976 | else if (inbytes < 0) | |
1977 | { | |
17c76198 PP |
1978 | record_io_error(state, (int) inbytes, US"recv", NULL); |
1979 | state->xfer_error = 1; | |
059ec3d9 PH |
1980 | return EOF; |
1981 | } | |
80a47a2c | 1982 | #ifndef DISABLE_DKIM |
17c76198 | 1983 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 1984 | #endif |
17c76198 PP |
1985 | state->xfer_buffer_hwm = (int) inbytes; |
1986 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
1987 | } |
1988 | ||
059ec3d9 PH |
1989 | /* Something in the buffer; return next uschar */ |
1990 | ||
17c76198 | 1991 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
1992 | } |
1993 | ||
1994 | ||
1995 | ||
17c76198 | 1996 | |
059ec3d9 PH |
1997 | /************************************************* |
1998 | * Read bytes from TLS channel * | |
1999 | *************************************************/ | |
2000 | ||
17c76198 PP |
2001 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
2002 | then the caller must feed DKIM. | |
817d9f57 | 2003 | |
059ec3d9 PH |
2004 | Arguments: |
2005 | buff buffer of data | |
2006 | len size of buffer | |
2007 | ||
2008 | Returns: the number of bytes read | |
2009 | -1 after a failed read | |
2010 | */ | |
2011 | ||
2012 | int | |
817d9f57 | 2013 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 2014 | { |
817d9f57 | 2015 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 2016 | ssize_t inbytes; |
059ec3d9 | 2017 | |
17c76198 PP |
2018 | if (len > INT_MAX) |
2019 | len = INT_MAX; | |
059ec3d9 | 2020 | |
17c76198 PP |
2021 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
2022 | DEBUG(D_tls) | |
2023 | debug_printf("*** PROBABLY A BUG *** " \ | |
2024 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
2025 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
2026 | ||
2027 | DEBUG(D_tls) | |
2028 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
2029 | state->session, buff, len); | |
2030 | ||
2031 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
2032 | if (inbytes > 0) return inbytes; |
2033 | if (inbytes == 0) | |
2034 | { | |
2035 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
2036 | } | |
17c76198 | 2037 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
2038 | |
2039 | return -1; | |
2040 | } | |
2041 | ||
2042 | ||
2043 | ||
17c76198 | 2044 | |
059ec3d9 PH |
2045 | /************************************************* |
2046 | * Write bytes down TLS channel * | |
2047 | *************************************************/ | |
2048 | ||
2049 | /* | |
2050 | Arguments: | |
817d9f57 | 2051 | is_server channel specifier |
059ec3d9 PH |
2052 | buff buffer of data |
2053 | len number of bytes | |
2054 | ||
2055 | Returns: the number of bytes after a successful write, | |
2056 | -1 after a failed write | |
2057 | */ | |
2058 | ||
2059 | int | |
817d9f57 | 2060 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 2061 | { |
17c76198 PP |
2062 | ssize_t outbytes; |
2063 | size_t left = len; | |
817d9f57 | 2064 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 2065 | |
17c76198 | 2066 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
2067 | while (left > 0) |
2068 | { | |
17c76198 PP |
2069 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
2070 | buff, left); | |
2071 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 2072 | |
17c76198 | 2073 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
2074 | if (outbytes < 0) |
2075 | { | |
17c76198 | 2076 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
2077 | return -1; |
2078 | } | |
2079 | if (outbytes == 0) | |
2080 | { | |
17c76198 | 2081 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
2082 | return -1; |
2083 | } | |
2084 | ||
2085 | left -= outbytes; | |
2086 | buff += outbytes; | |
2087 | } | |
2088 | ||
17c76198 PP |
2089 | if (len > INT_MAX) |
2090 | { | |
2091 | DEBUG(D_tls) | |
2092 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
2093 | len); | |
2094 | len = INT_MAX; | |
2095 | } | |
2096 | ||
2097 | return (int) len; | |
059ec3d9 PH |
2098 | } |
2099 | ||
2100 | ||
2101 | ||
17c76198 | 2102 | |
059ec3d9 | 2103 | /************************************************* |
17c76198 | 2104 | * Random number generation * |
059ec3d9 PH |
2105 | *************************************************/ |
2106 | ||
17c76198 PP |
2107 | /* Pseudo-random number generation. The result is not expected to be |
2108 | cryptographically strong but not so weak that someone will shoot themselves | |
2109 | in the foot using it as a nonce in input in some email header scheme or | |
2110 | whatever weirdness they'll twist this into. The result should handle fork() | |
2111 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 2112 | |
17c76198 PP |
2113 | Arguments: |
2114 | max range maximum | |
2115 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
2116 | */ |
2117 | ||
af3498d6 | 2118 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
2119 | int |
2120 | vaguely_random_number(int max) | |
059ec3d9 | 2121 | { |
17c76198 PP |
2122 | unsigned int r; |
2123 | int i, needed_len; | |
2124 | uschar *p; | |
2125 | uschar smallbuf[sizeof(r)]; | |
2126 | ||
2127 | if (max <= 1) | |
2128 | return 0; | |
2129 | ||
2130 | needed_len = sizeof(r); | |
2131 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
2132 | * asked for a number less than 10. */ | |
2133 | for (r = max, i = 0; r; ++i) | |
2134 | r >>= 1; | |
2135 | i = (i + 7) / 8; | |
2136 | if (i < needed_len) | |
2137 | needed_len = i; | |
2138 | ||
2139 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2140 | if (i < 0) | |
059ec3d9 | 2141 | { |
17c76198 PP |
2142 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2143 | return vaguely_random_number_fallback(max); | |
2144 | } | |
2145 | r = 0; | |
2146 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2147 | { | |
2148 | r *= 256; | |
2149 | r += *p; | |
059ec3d9 PH |
2150 | } |
2151 | ||
17c76198 PP |
2152 | /* We don't particularly care about weighted results; if someone wants |
2153 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2154 | return r % max; | |
059ec3d9 | 2155 | } |
af3498d6 PP |
2156 | #else /* HAVE_GNUTLS_RND */ |
2157 | int | |
2158 | vaguely_random_number(int max) | |
2159 | { | |
2160 | return vaguely_random_number_fallback(max); | |
2161 | } | |
2162 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2163 | |
36f12725 NM |
2164 | |
2165 | ||
2166 | ||
3375e053 PP |
2167 | /************************************************* |
2168 | * Let tls_require_ciphers be checked at startup * | |
2169 | *************************************************/ | |
2170 | ||
2171 | /* The tls_require_ciphers option, if set, must be something which the | |
2172 | library can parse. | |
2173 | ||
2174 | Returns: NULL on success, or error message | |
2175 | */ | |
2176 | ||
2177 | uschar * | |
2178 | tls_validate_require_cipher(void) | |
2179 | { | |
2180 | int rc; | |
2181 | uschar *expciphers = NULL; | |
2182 | gnutls_priority_t priority_cache; | |
2183 | const char *errpos; | |
2184 | ||
2185 | #define validate_check_rc(Label) do { \ | |
2186 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2187 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2188 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2189 | ||
2190 | if (exim_gnutls_base_init_done) | |
2191 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2192 | "already initialised GnuTLS, Exim developer bug"); | |
2193 | ||
a5f239e4 | 2194 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2195 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2196 | { |
2197 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2198 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2199 | } | |
2200 | #endif | |
3375e053 PP |
2201 | rc = gnutls_global_init(); |
2202 | validate_check_rc(US"gnutls_global_init()"); | |
2203 | exim_gnutls_base_init_done = TRUE; | |
2204 | ||
2205 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2206 | return_deinit(NULL); | |
2207 | ||
2208 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2209 | return_deinit(US"failed to expand tls_require_ciphers"); | |
2210 | ||
2211 | if (!(expciphers && *expciphers)) | |
2212 | return_deinit(NULL); | |
2213 | ||
2214 | DEBUG(D_tls) | |
2215 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2216 | ||
2217 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2218 | validate_check_rc(string_sprintf( | |
2219 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2220 | expciphers, errpos - CS expciphers, errpos)); | |
2221 | ||
2222 | #undef return_deinit | |
2223 | #undef validate_check_rc | |
2224 | gnutls_global_deinit(); | |
2225 | ||
2226 | return NULL; | |
2227 | } | |
2228 | ||
2229 | ||
2230 | ||
2231 | ||
36f12725 NM |
2232 | /************************************************* |
2233 | * Report the library versions. * | |
2234 | *************************************************/ | |
2235 | ||
2236 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2237 | ||
2238 | Arguments: a FILE* to print the results to | |
2239 | Returns: nothing | |
2240 | */ | |
2241 | ||
2242 | void | |
2243 | tls_version_report(FILE *f) | |
2244 | { | |
754a0503 PP |
2245 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2246 | " Runtime: %s\n", | |
2247 | LIBGNUTLS_VERSION, | |
2248 | gnutls_check_version(NULL)); | |
36f12725 NM |
2249 | } |
2250 | ||
2b4a568d JH |
2251 | /* vi: aw ai sw=2 |
2252 | */ | |
059ec3d9 | 2253 | /* End of tls-gnu.c */ |