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 | |
17c76198 | 63 | enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; |
059ec3d9 | 64 | |
17c76198 PP |
65 | /* This holds most state for server or client; with this, we can set up an |
66 | outbound TLS-enabled connection in an ACL callout, while not stomping all | |
67 | over the TLS variables available for expansion. | |
059ec3d9 | 68 | |
17c76198 PP |
69 | Some of these correspond to variables in globals.c; those variables will |
70 | be set to point to content in one of these instances, as appropriate for | |
71 | the stage of the process lifetime. | |
059ec3d9 | 72 | |
389ca47a | 73 | Not handled here: global tls_channelbinding_b64. |
17c76198 | 74 | */ |
059ec3d9 | 75 | |
17c76198 PP |
76 | typedef struct exim_gnutls_state { |
77 | gnutls_session_t session; | |
78 | gnutls_certificate_credentials_t x509_cred; | |
79 | gnutls_priority_t priority_cache; | |
80 | enum peer_verify_requirement verify_requirement; | |
81 | int fd_in; | |
82 | int fd_out; | |
83 | BOOL peer_cert_verified; | |
84 | BOOL trigger_sni_changes; | |
4fe99a6c | 85 | BOOL have_set_peerdn; |
17c76198 PP |
86 | const struct host_item *host; |
87 | uschar *peerdn; | |
75fe387d | 88 | uschar *ciphersuite; |
17c76198 PP |
89 | uschar *received_sni; |
90 | ||
91 | const uschar *tls_certificate; | |
92 | const uschar *tls_privatekey; | |
93 | const uschar *tls_sni; /* client send only, not received */ | |
94 | const uschar *tls_verify_certificates; | |
95 | const uschar *tls_crl; | |
96 | const uschar *tls_require_ciphers; | |
97 | uschar *exp_tls_certificate; | |
98 | uschar *exp_tls_privatekey; | |
99 | uschar *exp_tls_sni; | |
100 | uschar *exp_tls_verify_certificates; | |
101 | uschar *exp_tls_crl; | |
102 | uschar *exp_tls_require_ciphers; | |
103 | ||
389ca47a | 104 | tls_support *tlsp; /* set in tls_init() */ |
817d9f57 | 105 | |
17c76198 PP |
106 | uschar *xfer_buffer; |
107 | int xfer_buffer_lwm; | |
108 | int xfer_buffer_hwm; | |
109 | int xfer_eof; | |
110 | int xfer_error; | |
17c76198 PP |
111 | } exim_gnutls_state_st; |
112 | ||
113 | static const exim_gnutls_state_st exim_gnutls_state_init = { | |
4fe99a6c | 114 | NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, |
75fe387d | 115 | NULL, NULL, NULL, NULL, |
17c76198 PP |
116 | NULL, NULL, NULL, NULL, NULL, NULL, |
117 | NULL, NULL, NULL, NULL, NULL, NULL, | |
817d9f57 | 118 | NULL, |
17c76198 | 119 | NULL, 0, 0, 0, 0, |
17c76198 | 120 | }; |
83da1223 | 121 | |
17c76198 PP |
122 | /* Not only do we have our own APIs which don't pass around state, assuming |
123 | it's held in globals, GnuTLS doesn't appear to let us register callback data | |
124 | for callbacks, or as part of the session, so we have to keep a "this is the | |
125 | context we're currently dealing with" pointer and rely upon being | |
126 | single-threaded to keep from processing data on an inbound TLS connection while | |
127 | talking to another TLS connection for an outbound check. This does mean that | |
128 | there's no way for heart-beats to be responded to, for the duration of the | |
129 | second connection. */ | |
059ec3d9 | 130 | |
17c76198 | 131 | static exim_gnutls_state_st state_server, state_client; |
059ec3d9 | 132 | |
17c76198 PP |
133 | /* dh_params are initialised once within the lifetime of a process using TLS; |
134 | if we used TLS in a long-lived daemon, we'd have to reconsider this. But we | |
135 | don't want to repeat this. */ | |
83da1223 | 136 | |
17c76198 | 137 | static gnutls_dh_params_t dh_server_params = NULL; |
059ec3d9 | 138 | |
17c76198 | 139 | /* No idea how this value was chosen; preserving it. Default is 3600. */ |
059ec3d9 | 140 | |
17c76198 | 141 | static const int ssl_session_timeout = 200; |
059ec3d9 | 142 | |
17c76198 | 143 | static const char * const exim_default_gnutls_priority = "NORMAL"; |
83da1223 | 144 | |
17c76198 | 145 | /* Guard library core initialisation */ |
83da1223 | 146 | |
17c76198 | 147 | static BOOL exim_gnutls_base_init_done = FALSE; |
059ec3d9 | 148 | |
059ec3d9 | 149 | |
17c76198 PP |
150 | /* ------------------------------------------------------------------------ */ |
151 | /* macros */ | |
83da1223 | 152 | |
17c76198 | 153 | #define MAX_HOST_LEN 255 |
83da1223 | 154 | |
17c76198 PP |
155 | /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup |
156 | the library logging; a value less than 0 disables the calls to set up logging | |
157 | callbacks. */ | |
2c17bb02 | 158 | #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL |
17c76198 | 159 | #define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 |
2c17bb02 | 160 | #endif |
83da1223 | 161 | |
2c17bb02 | 162 | #ifndef EXIM_CLIENT_DH_MIN_BITS |
bba74fc6 | 163 | #define EXIM_CLIENT_DH_MIN_BITS 1024 |
2c17bb02 | 164 | #endif |
83da1223 | 165 | |
af3498d6 PP |
166 | /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we |
167 | can ask for a bit-strength. Without that, we stick to the constant we had | |
168 | before, for now. */ | |
2c17bb02 | 169 | #ifndef EXIM_SERVER_DH_BITS_PRE2_12 |
af3498d6 | 170 | #define EXIM_SERVER_DH_BITS_PRE2_12 1024 |
2c17bb02 | 171 | #endif |
af3498d6 | 172 | |
17c76198 PP |
173 | #define exim_gnutls_err_check(Label) do { \ |
174 | if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) | |
059ec3d9 | 175 | |
17c76198 | 176 | #define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) |
83da1223 | 177 | |
17c76198 PP |
178 | #if GNUTLS_VERSION_NUMBER >= 0x020c00 |
179 | #define HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
af3498d6 PP |
180 | #define HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
181 | #define HAVE_GNUTLS_RND | |
2519e60d TL |
182 | /* The security fix we provide with the gnutls_allow_auto_pkcs11 option |
183 | * (4.82 PP/09) introduces a compatibility regression. The symbol simply | |
184 | * isn't available sometimes, so this needs to become a conditional | |
185 | * compilation; the sanest way to deal with this being a problem on | |
186 | * older OSes is to block it in the Local/Makefile with this compiler | |
187 | * definition */ | |
188 | #ifndef AVOID_GNUTLS_PKCS11 | |
a5f239e4 | 189 | #define HAVE_GNUTLS_PKCS11 |
2519e60d | 190 | #endif /* AVOID_GNUTLS_PKCS11 */ |
17c76198 | 191 | #endif |
83da1223 | 192 | |
af3498d6 PP |
193 | |
194 | ||
195 | ||
196 | /* ------------------------------------------------------------------------ */ | |
197 | /* Callback declarations */ | |
198 | ||
199 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
200 | static void exim_gnutls_logger_cb(int level, const char *message); | |
201 | #endif | |
202 | ||
203 | static int exim_sni_handling_cb(gnutls_session_t session); | |
204 | ||
205 | ||
206 | ||
207 | ||
17c76198 PP |
208 | /* ------------------------------------------------------------------------ */ |
209 | /* Static functions */ | |
059ec3d9 PH |
210 | |
211 | /************************************************* | |
212 | * Handle TLS error * | |
213 | *************************************************/ | |
214 | ||
215 | /* Called from lots of places when errors occur before actually starting to do | |
216 | the TLS handshake, that is, while the session is still in clear. Always returns | |
217 | DEFER for a server and FAIL for a client so that most calls can use "return | |
218 | tls_error(...)" to do this processing and then give an appropriate return. A | |
219 | single function is used for both server and client, because it is called from | |
220 | some shared functions. | |
221 | ||
222 | Argument: | |
223 | prefix text to include in the logged error | |
7199e1ee TF |
224 | msg additional error string (may be NULL) |
225 | usually obtained from gnutls_strerror() | |
17c76198 PP |
226 | host NULL if setting up a server; |
227 | the connected host if setting up a client | |
059ec3d9 PH |
228 | |
229 | Returns: OK/DEFER/FAIL | |
230 | */ | |
231 | ||
232 | static int | |
17c76198 | 233 | tls_error(const uschar *prefix, const char *msg, const host_item *host) |
059ec3d9 | 234 | { |
17c76198 PP |
235 | if (host) |
236 | { | |
237 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", | |
238 | host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); | |
239 | return FAIL; | |
240 | } | |
241 | else | |
059ec3d9 | 242 | { |
7199e1ee | 243 | uschar *conn_info = smtp_get_connection_info(); |
17c76198 | 244 | if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) |
7199e1ee TF |
245 | conn_info += 5; |
246 | log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", | |
17c76198 | 247 | conn_info, prefix, msg ? ": " : "", msg ? msg : ""); |
059ec3d9 PH |
248 | return DEFER; |
249 | } | |
059ec3d9 PH |
250 | } |
251 | ||
252 | ||
253 | ||
17c76198 | 254 | |
059ec3d9 | 255 | /************************************************* |
17c76198 | 256 | * Deal with logging errors during I/O * |
059ec3d9 PH |
257 | *************************************************/ |
258 | ||
17c76198 | 259 | /* We have to get the identity of the peer from saved data. |
059ec3d9 | 260 | |
17c76198 PP |
261 | Argument: |
262 | state the current GnuTLS exim state container | |
263 | rc the GnuTLS error code, or 0 if it's a local error | |
264 | when text identifying read or write | |
265 | text local error text when ec is 0 | |
059ec3d9 | 266 | |
17c76198 | 267 | Returns: nothing |
059ec3d9 PH |
268 | */ |
269 | ||
17c76198 PP |
270 | static void |
271 | record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) | |
059ec3d9 | 272 | { |
17c76198 | 273 | const char *msg; |
059ec3d9 | 274 | |
17c76198 PP |
275 | if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) |
276 | msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), | |
277 | US gnutls_alert_get_name(gnutls_alert_get(state->session))); | |
278 | else | |
279 | msg = gnutls_strerror(rc); | |
059ec3d9 | 280 | |
17c76198 PP |
281 | tls_error(when, msg, state->host); |
282 | } | |
059ec3d9 | 283 | |
059ec3d9 | 284 | |
059ec3d9 | 285 | |
059ec3d9 | 286 | |
17c76198 PP |
287 | /************************************************* |
288 | * Set various Exim expansion vars * | |
289 | *************************************************/ | |
059ec3d9 | 290 | |
17c76198 PP |
291 | /* We set various Exim global variables from the state, once a session has |
292 | been established. With TLS callouts, may need to change this to stack | |
293 | variables, or just re-call it with the server state after client callout | |
294 | has finished. | |
059ec3d9 | 295 | |
17c76198 PP |
296 | Make sure anything set here is inset in tls_getc(). |
297 | ||
298 | Sets: | |
299 | tls_active fd | |
300 | tls_bits strength indicator | |
301 | tls_certificate_verified bool indicator | |
302 | tls_channelbinding_b64 for some SASL mechanisms | |
303 | tls_cipher a string | |
304 | tls_peerdn a string | |
305 | tls_sni a (UTF-8) string | |
17c76198 PP |
306 | |
307 | Argument: | |
308 | state the relevant exim_gnutls_state_st * | |
309 | */ | |
310 | ||
311 | static void | |
817d9f57 | 312 | extract_exim_vars_from_tls_state(exim_gnutls_state_st *state, BOOL is_server) |
17c76198 | 313 | { |
17c76198 | 314 | gnutls_cipher_algorithm_t cipher; |
17c76198 PP |
315 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING |
316 | int old_pool; | |
317 | int rc; | |
318 | gnutls_datum_t channel; | |
319 | #endif | |
320 | ||
817d9f57 | 321 | state->tlsp->active = state->fd_out; |
17c76198 PP |
322 | |
323 | cipher = gnutls_cipher_get(state->session); | |
324 | /* returns size in "bytes" */ | |
817d9f57 | 325 | state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; |
17c76198 | 326 | |
817d9f57 | 327 | state->tlsp->cipher = state->ciphersuite; |
17c76198 | 328 | |
817d9f57 | 329 | DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); |
17c76198 | 330 | |
817d9f57 | 331 | state->tlsp->certificate_verified = state->peer_cert_verified; |
059ec3d9 | 332 | |
17c76198 PP |
333 | /* note that tls_channelbinding_b64 is not saved to the spool file, since it's |
334 | only available for use for authenticators while this TLS session is running. */ | |
335 | ||
336 | tls_channelbinding_b64 = NULL; | |
337 | #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING | |
338 | channel.data = NULL; | |
339 | channel.size = 0; | |
340 | rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); | |
341 | if (rc) { | |
342 | DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); | |
343 | } else { | |
344 | old_pool = store_pool; | |
345 | store_pool = POOL_PERM; | |
346 | tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); | |
347 | store_pool = old_pool; | |
348 | DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); | |
349 | } | |
350 | #endif | |
351 | ||
817d9f57 JH |
352 | state->tlsp->peerdn = state->peerdn; |
353 | state->tlsp->sni = state->received_sni; | |
059ec3d9 PH |
354 | } |
355 | ||
356 | ||
357 | ||
17c76198 | 358 | |
059ec3d9 | 359 | /************************************************* |
575643cd | 360 | * Setup up DH parameters * |
059ec3d9 PH |
361 | *************************************************/ |
362 | ||
575643cd | 363 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
364 | be re-generated every so often, depending on security policy. What we do is to |
365 | keep these parameters in a file in the spool directory. If the file does not | |
366 | exist, we generate them. This means that it is easy to cause a regeneration. | |
367 | ||
368 | The new file is written as a temporary file and renamed, so that an incomplete | |
369 | file is never present. If two processes both compute some new parameters, you | |
370 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
371 | prevent this. | |
372 | ||
059ec3d9 PH |
373 | Returns: OK/DEFER/FAIL |
374 | */ | |
375 | ||
376 | static int | |
17c76198 | 377 | init_server_dh(void) |
059ec3d9 | 378 | { |
17c76198 PP |
379 | int fd, rc; |
380 | unsigned int dh_bits; | |
b5aea5e1 | 381 | gnutls_datum m; |
a799883d PP |
382 | uschar filename_buf[PATH_MAX]; |
383 | uschar *filename = NULL; | |
17c76198 | 384 | size_t sz; |
a799883d PP |
385 | uschar *exp_tls_dhparam; |
386 | BOOL use_file_in_spool = FALSE; | |
387 | BOOL use_fixed_file = FALSE; | |
17c76198 | 388 | host_item *host = NULL; /* dummy for macros */ |
059ec3d9 | 389 | |
17c76198 | 390 | DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); |
059ec3d9 | 391 | |
17c76198 PP |
392 | rc = gnutls_dh_params_init(&dh_server_params); |
393 | exim_gnutls_err_check(US"gnutls_dh_params_init"); | |
059ec3d9 | 394 | |
a799883d PP |
395 | m.data = NULL; |
396 | m.size = 0; | |
397 | ||
398 | if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) | |
399 | return DEFER; | |
400 | ||
401 | if (!exp_tls_dhparam) | |
402 | { | |
403 | DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); | |
404 | m.data = US std_dh_prime_default(); | |
405 | m.size = Ustrlen(m.data); | |
406 | } | |
407 | else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) | |
408 | use_file_in_spool = TRUE; | |
409 | else if (Ustrcmp(exp_tls_dhparam, "none") == 0) | |
410 | { | |
411 | DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); | |
412 | return OK; | |
413 | } | |
414 | else if (exp_tls_dhparam[0] != '/') | |
415 | { | |
416 | m.data = US std_dh_prime_named(exp_tls_dhparam); | |
417 | if (m.data == NULL) | |
418 | return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); | |
419 | m.size = Ustrlen(m.data); | |
420 | } | |
421 | else | |
422 | { | |
423 | use_fixed_file = TRUE; | |
424 | filename = exp_tls_dhparam; | |
425 | } | |
426 | ||
427 | if (m.data) | |
428 | { | |
429 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); | |
430 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); | |
431 | DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); | |
432 | return OK; | |
433 | } | |
434 | ||
af3498d6 PP |
435 | #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS |
436 | /* If you change this constant, also change dh_param_fn_ext so that we can use a | |
17c76198 PP |
437 | different filename and ensure we have sufficient bits. */ |
438 | dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); | |
439 | if (!dh_bits) | |
440 | return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); | |
af3498d6 | 441 | DEBUG(D_tls) |
b34fc30c | 442 | debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", |
af3498d6 PP |
443 | dh_bits); |
444 | #else | |
445 | dh_bits = EXIM_SERVER_DH_BITS_PRE2_12; | |
446 | DEBUG(D_tls) | |
447 | debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n", | |
448 | dh_bits); | |
449 | #endif | |
059ec3d9 | 450 | |
3375e053 PP |
451 | /* Some clients have hard-coded limits. */ |
452 | if (dh_bits > tls_dh_max_bits) | |
453 | { | |
454 | DEBUG(D_tls) | |
455 | debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", | |
456 | tls_dh_max_bits); | |
457 | dh_bits = tls_dh_max_bits; | |
458 | } | |
459 | ||
a799883d PP |
460 | if (use_file_in_spool) |
461 | { | |
462 | if (!string_format(filename_buf, sizeof(filename_buf), | |
463 | "%s/gnutls-params-%d", spool_directory, dh_bits)) | |
464 | return tls_error(US"overlong filename", NULL, NULL); | |
465 | filename = filename_buf; | |
466 | } | |
059ec3d9 | 467 | |
b5aea5e1 | 468 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 469 | parameters. */ |
059ec3d9 PH |
470 | |
471 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 472 | if (fd >= 0) |
059ec3d9 | 473 | { |
b5aea5e1 | 474 | struct stat statbuf; |
17c76198 PP |
475 | FILE *fp; |
476 | int saved_errno; | |
477 | ||
478 | if (fstat(fd, &statbuf) < 0) /* EIO */ | |
479 | { | |
480 | saved_errno = errno; | |
481 | (void)close(fd); | |
482 | return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); | |
483 | } | |
484 | if (!S_ISREG(statbuf.st_mode)) | |
b5aea5e1 PH |
485 | { |
486 | (void)close(fd); | |
17c76198 PP |
487 | return tls_error(US"TLS cache not a file", NULL, NULL); |
488 | } | |
489 | fp = fdopen(fd, "rb"); | |
490 | if (!fp) | |
491 | { | |
492 | saved_errno = errno; | |
493 | (void)close(fd); | |
494 | return tls_error(US"fdopen(TLS cache stat fd) failed", | |
495 | strerror(saved_errno), NULL); | |
b5aea5e1 | 496 | } |
059ec3d9 | 497 | |
b5aea5e1 PH |
498 | m.size = statbuf.st_size; |
499 | m.data = malloc(m.size); | |
500 | if (m.data == NULL) | |
17c76198 PP |
501 | { |
502 | fclose(fp); | |
503 | return tls_error(US"malloc failed", strerror(errno), NULL); | |
504 | } | |
505 | sz = fread(m.data, m.size, 1, fp); | |
506 | if (!sz) | |
507 | { | |
508 | saved_errno = errno; | |
509 | fclose(fp); | |
510 | free(m.data); | |
511 | return tls_error(US"fread failed", strerror(saved_errno), NULL); | |
512 | } | |
513 | fclose(fp); | |
b5aea5e1 | 514 | |
17c76198 | 515 | rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); |
b5aea5e1 | 516 | free(m.data); |
17c76198 PP |
517 | exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); |
518 | DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); | |
b5aea5e1 PH |
519 | } |
520 | ||
521 | /* If the file does not exist, fall through to compute new data and cache it. | |
522 | If there was any other opening error, it is serious. */ | |
523 | ||
182ad5cf PH |
524 | else if (errno == ENOENT) |
525 | { | |
17c76198 | 526 | rc = -1; |
182ad5cf | 527 | DEBUG(D_tls) |
17c76198 | 528 | debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); |
182ad5cf PH |
529 | } |
530 | else | |
17c76198 PP |
531 | return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), |
532 | NULL, NULL); | |
b5aea5e1 PH |
533 | |
534 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
535 | is not useful. One particular case of this is when upgrading from an older | |
536 | release of Exim in which the data was stored in a different format. We don't | |
537 | try to be clever and support both formats; we just regenerate new data in this | |
538 | case. */ | |
539 | ||
17c76198 | 540 | if (rc < 0) |
b5aea5e1 | 541 | { |
17c76198 | 542 | uschar *temp_fn; |
201f5254 | 543 | unsigned int dh_bits_gen = dh_bits; |
059ec3d9 | 544 | |
17c76198 PP |
545 | if ((PATH_MAX - Ustrlen(filename)) < 10) |
546 | return tls_error(US"Filename too long to generate replacement", | |
547 | CS filename, NULL); | |
059ec3d9 | 548 | |
17c76198 PP |
549 | temp_fn = string_copy(US "%s.XXXXXXX"); |
550 | fd = mkstemp(CS temp_fn); /* modifies temp_fn */ | |
059ec3d9 | 551 | if (fd < 0) |
17c76198 | 552 | return tls_error(US"Unable to open temp file", strerror(errno), NULL); |
059ec3d9 PH |
553 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ |
554 | ||
201f5254 PP |
555 | /* GnuTLS overshoots! |
556 | * If we ask for 2236, we might get 2237 or more. | |
557 | * But there's no way to ask GnuTLS how many bits there really are. | |
558 | * We can ask how many bits were used in a TLS session, but that's it! | |
559 | * The prime itself is hidden behind too much abstraction. | |
560 | * So we ask for less, and proceed on a wing and a prayer. | |
561 | * First attempt, subtracted 3 for 2233 and got 2240. | |
562 | */ | |
cae6e576 | 563 | if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) |
201f5254 PP |
564 | { |
565 | dh_bits_gen = dh_bits - 10; | |
566 | DEBUG(D_tls) | |
567 | debug_printf("being paranoid about DH generation, make it '%d' bits'\n", | |
568 | dh_bits_gen); | |
569 | } | |
570 | ||
571 | DEBUG(D_tls) | |
572 | debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", | |
573 | dh_bits_gen); | |
574 | rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); | |
17c76198 PP |
575 | exim_gnutls_err_check(US"gnutls_dh_params_generate2"); |
576 | ||
577 | /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, | |
578 | and I confirmed that a NULL call to get the size first is how the GnuTLS | |
579 | sample apps handle this. */ | |
580 | ||
581 | sz = 0; | |
582 | m.data = NULL; | |
583 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, | |
584 | m.data, &sz); | |
585 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
586 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); | |
587 | m.size = sz; | |
b5aea5e1 PH |
588 | m.data = malloc(m.size); |
589 | if (m.data == NULL) | |
17c76198 | 590 | return tls_error(US"memory allocation failed", strerror(errno), NULL); |
1f00591e | 591 | /* this will return a size 1 less than the allocation size above */ |
17c76198 | 592 | rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, |
1f00591e | 593 | m.data, &sz); |
17c76198 PP |
594 | if (rc != GNUTLS_E_SUCCESS) |
595 | { | |
596 | free(m.data); | |
597 | exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); | |
598 | } | |
1f00591e | 599 | m.size = sz; /* shrink by 1, probably */ |
059ec3d9 | 600 | |
17c76198 PP |
601 | sz = write_to_fd_buf(fd, m.data, (size_t) m.size); |
602 | if (sz != m.size) | |
603 | { | |
604 | free(m.data); | |
605 | return tls_error(US"TLS cache write D-H params failed", | |
606 | strerror(errno), NULL); | |
607 | } | |
b5aea5e1 | 608 | free(m.data); |
17c76198 PP |
609 | sz = write_to_fd_buf(fd, US"\n", 1); |
610 | if (sz != 1) | |
611 | return tls_error(US"TLS cache write D-H params final newline failed", | |
612 | strerror(errno), NULL); | |
613 | ||
614 | rc = close(fd); | |
615 | if (rc) | |
616 | return tls_error(US"TLS cache write close() failed", | |
617 | strerror(errno), NULL); | |
059ec3d9 | 618 | |
17c76198 PP |
619 | if (Urename(temp_fn, filename) < 0) |
620 | return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", | |
621 | temp_fn, filename), strerror(errno), NULL); | |
059ec3d9 | 622 | |
17c76198 | 623 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); |
059ec3d9 PH |
624 | } |
625 | ||
17c76198 | 626 | DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); |
059ec3d9 PH |
627 | return OK; |
628 | } | |
629 | ||
630 | ||
631 | ||
632 | ||
633 | /************************************************* | |
17c76198 | 634 | * Variables re-expanded post-SNI * |
059ec3d9 PH |
635 | *************************************************/ |
636 | ||
17c76198 PP |
637 | /* Called from both server and client code, via tls_init(), and also from |
638 | the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". | |
639 | ||
640 | We can tell the two apart by state->received_sni being non-NULL in callback. | |
641 | ||
642 | The callback should not call us unless state->trigger_sni_changes is true, | |
643 | which we are responsible for setting on the first pass through. | |
059ec3d9 PH |
644 | |
645 | Arguments: | |
17c76198 | 646 | state exim_gnutls_state_st * |
059ec3d9 PH |
647 | |
648 | Returns: OK/DEFER/FAIL | |
649 | */ | |
650 | ||
651 | static int | |
17c76198 | 652 | tls_expand_session_files(exim_gnutls_state_st *state) |
059ec3d9 | 653 | { |
1365611d | 654 | struct stat statbuf; |
059ec3d9 | 655 | int rc; |
17c76198 PP |
656 | const host_item *host = state->host; /* macro should be reconsidered? */ |
657 | uschar *saved_tls_certificate = NULL; | |
658 | uschar *saved_tls_privatekey = NULL; | |
659 | uschar *saved_tls_verify_certificates = NULL; | |
660 | uschar *saved_tls_crl = NULL; | |
661 | int cert_count; | |
662 | ||
663 | /* We check for tls_sni *before* expansion. */ | |
2b4a568d | 664 | if (!host) /* server */ |
17c76198 PP |
665 | { |
666 | if (!state->received_sni) | |
667 | { | |
d9b2312b JH |
668 | if (state->tls_certificate && |
669 | (Ustrstr(state->tls_certificate, US"tls_sni") || | |
670 | Ustrstr(state->tls_certificate, US"tls_in_sni") || | |
671 | Ustrstr(state->tls_certificate, US"tls_out_sni") | |
672 | )) | |
17c76198 PP |
673 | { |
674 | DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); | |
675 | state->trigger_sni_changes = TRUE; | |
676 | } | |
677 | } | |
678 | else | |
679 | { | |
1365611d | 680 | /* useful for debugging */ |
17c76198 PP |
681 | saved_tls_certificate = state->exp_tls_certificate; |
682 | saved_tls_privatekey = state->exp_tls_privatekey; | |
683 | saved_tls_verify_certificates = state->exp_tls_verify_certificates; | |
684 | saved_tls_crl = state->exp_tls_crl; | |
685 | } | |
686 | } | |
059ec3d9 | 687 | |
1365611d PP |
688 | rc = gnutls_certificate_allocate_credentials(&state->x509_cred); |
689 | exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); | |
690 | ||
17c76198 PP |
691 | /* remember: expand_check_tlsvar() is expand_check() but fiddling with |
692 | state members, assuming consistent naming; and expand_check() returns | |
693 | false if expansion failed, unless expansion was forced to fail. */ | |
059ec3d9 | 694 | |
17c76198 PP |
695 | /* check if we at least have a certificate, before doing expensive |
696 | D-H generation. */ | |
059ec3d9 | 697 | |
17c76198 PP |
698 | if (!expand_check_tlsvar(tls_certificate)) |
699 | return DEFER; | |
059ec3d9 | 700 | |
17c76198 | 701 | /* certificate is mandatory in server, optional in client */ |
059ec3d9 | 702 | |
17c76198 PP |
703 | if ((state->exp_tls_certificate == NULL) || |
704 | (*state->exp_tls_certificate == '\0')) | |
705 | { | |
2b4a568d | 706 | if (!host) |
17c76198 PP |
707 | return tls_error(US"no TLS server certificate is specified", NULL, NULL); |
708 | else | |
709 | DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); | |
710 | } | |
059ec3d9 | 711 | |
17c76198 | 712 | if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) |
059ec3d9 PH |
713 | return DEFER; |
714 | ||
17c76198 PP |
715 | /* tls_privatekey is optional, defaulting to same file as certificate */ |
716 | ||
717 | if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') | |
059ec3d9 | 718 | { |
17c76198 PP |
719 | state->tls_privatekey = state->tls_certificate; |
720 | state->exp_tls_privatekey = state->exp_tls_certificate; | |
059ec3d9 | 721 | } |
c91535f3 | 722 | |
059ec3d9 | 723 | |
17c76198 | 724 | if (state->exp_tls_certificate && *state->exp_tls_certificate) |
059ec3d9 PH |
725 | { |
726 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
17c76198 PP |
727 | state->exp_tls_certificate, state->exp_tls_privatekey); |
728 | ||
729 | if (state->received_sni) | |
de365ded | 730 | { |
17c76198 PP |
731 | if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && |
732 | (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) | |
733 | { | |
b34fc30c | 734 | DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); |
17c76198 PP |
735 | } |
736 | else | |
737 | { | |
b34fc30c | 738 | DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); |
17c76198 | 739 | } |
8e669ac1 | 740 | } |
059ec3d9 | 741 | |
1365611d PP |
742 | rc = gnutls_certificate_set_x509_key_file(state->x509_cred, |
743 | CS state->exp_tls_certificate, CS state->exp_tls_privatekey, | |
744 | GNUTLS_X509_FMT_PEM); | |
745 | exim_gnutls_err_check( | |
746 | string_sprintf("cert/key setup: cert=%s key=%s", | |
747 | state->exp_tls_certificate, state->exp_tls_privatekey)); | |
748 | DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); | |
b34fc30c | 749 | } /* tls_certificate */ |
059ec3d9 | 750 | |
2b4a568d JH |
751 | |
752 | /* Set the OCSP stapling server info */ | |
753 | ||
754 | #ifdef EXPERIMENTAL_OCSP | |
755 | if ( !host /* server */ | |
756 | && tls_ocsp_file | |
757 | ) | |
758 | { | |
759 | uschar * expanded; | |
760 | int rc; | |
761 | ||
762 | if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &expanded)) | |
763 | return DEFER; | |
764 | ||
765 | /* Lazy way; would like callback to emit debug on actual response */ | |
766 | ||
767 | rc = gnutls_certificate_set_ocsp_status_request_file(state->x509_cred, | |
768 | expanded, 0); | |
769 | exim_gnutls_err_check(US"gnutls_certificate_set_ocsp_status_request_file"); | |
770 | DEBUG(D_tls) debug_printf("Set OCSP response file %s\n", expanded); | |
771 | } | |
772 | #endif | |
773 | ||
774 | ||
059ec3d9 PH |
775 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is |
776 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
777 | error message is provided. However, if we just refrain from setting anything up | |
778 | in that case, certificate verification fails, which seems to be the correct | |
779 | behaviour. */ | |
780 | ||
17c76198 | 781 | if (state->tls_verify_certificates && *state->tls_verify_certificates) |
059ec3d9 | 782 | { |
17c76198 | 783 | if (!expand_check_tlsvar(tls_verify_certificates)) |
059ec3d9 | 784 | return DEFER; |
17c76198 PP |
785 | if (state->tls_crl && *state->tls_crl) |
786 | if (!expand_check_tlsvar(tls_crl)) | |
787 | return DEFER; | |
059ec3d9 | 788 | |
1365611d PP |
789 | if (!(state->exp_tls_verify_certificates && |
790 | *state->exp_tls_verify_certificates)) | |
b34fc30c PP |
791 | { |
792 | DEBUG(D_tls) | |
1365611d PP |
793 | debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); |
794 | /* With no tls_verify_certificates, we ignore tls_crl too */ | |
17c76198 | 795 | return OK; |
b34fc30c | 796 | } |
1365611d | 797 | } |
83e2f8a2 PP |
798 | else |
799 | { | |
800 | DEBUG(D_tls) | |
801 | debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); | |
802 | return OK; | |
803 | } | |
17c76198 | 804 | |
1365611d PP |
805 | if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) |
806 | { | |
807 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
808 | "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, | |
809 | strerror(errno)); | |
810 | return DEFER; | |
811 | } | |
17c76198 | 812 | |
619b2b25 PP |
813 | /* The test suite passes in /dev/null; we could check for that path explicitly, |
814 | but who knows if someone has some weird FIFO which always dumps some certs, or | |
815 | other weirdness. The thing we really want to check is that it's not a | |
816 | directory, since while OpenSSL supports that, GnuTLS does not. | |
817 | So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ | |
818 | if (S_ISDIR(statbuf.st_mode)) | |
1365611d PP |
819 | { |
820 | DEBUG(D_tls) | |
619b2b25 PP |
821 | debug_printf("verify certificates path is a dir: \"%s\"\n", |
822 | state->exp_tls_verify_certificates); | |
1365611d | 823 | log_write(0, LOG_MAIN|LOG_PANIC, |
619b2b25 | 824 | "tls_verify_certificates \"%s\" is a directory", |
1365611d PP |
825 | state->exp_tls_verify_certificates); |
826 | return DEFER; | |
827 | } | |
059ec3d9 | 828 | |
1365611d PP |
829 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
830 | state->exp_tls_verify_certificates, statbuf.st_size); | |
059ec3d9 | 831 | |
1365611d PP |
832 | if (statbuf.st_size == 0) |
833 | { | |
834 | DEBUG(D_tls) | |
835 | debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); | |
836 | return OK; | |
837 | } | |
059ec3d9 | 838 | |
1365611d PP |
839 | cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, |
840 | CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); | |
841 | if (cert_count < 0) | |
842 | { | |
843 | rc = cert_count; | |
844 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); | |
845 | } | |
846 | DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); | |
059ec3d9 | 847 | |
5c8cda3a PP |
848 | if (state->tls_crl && *state->tls_crl && |
849 | state->exp_tls_crl && *state->exp_tls_crl) | |
1365611d | 850 | { |
5c8cda3a PP |
851 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); |
852 | cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, | |
853 | CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); | |
854 | if (cert_count < 0) | |
1365611d | 855 | { |
5c8cda3a | 856 | rc = cert_count; |
1365611d PP |
857 | exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); |
858 | } | |
5c8cda3a | 859 | DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); |
1365611d | 860 | } |
059ec3d9 | 861 | |
059ec3d9 PH |
862 | return OK; |
863 | } | |
864 | ||
865 | ||
866 | ||
867 | ||
1365611d PP |
868 | /************************************************* |
869 | * Set X.509 state variables * | |
870 | *************************************************/ | |
871 | ||
872 | /* In GnuTLS, the registered cert/key are not replaced by a later | |
873 | set of a cert/key, so for SNI support we need a whole new x509_cred | |
874 | structure. Which means various other non-re-expanded pieces of state | |
875 | need to be re-set in the new struct, so the setting logic is pulled | |
876 | out to this. | |
877 | ||
878 | Arguments: | |
879 | state exim_gnutls_state_st * | |
880 | ||
881 | Returns: OK/DEFER/FAIL | |
882 | */ | |
883 | ||
884 | static int | |
885 | tls_set_remaining_x509(exim_gnutls_state_st *state) | |
886 | { | |
887 | int rc; | |
888 | const host_item *host = state->host; /* macro should be reconsidered? */ | |
889 | ||
890 | /* Create D-H parameters, or read them from the cache file. This function does | |
891 | its own SMTP error messaging. This only happens for the server, TLS D-H ignores | |
892 | client-side params. */ | |
893 | ||
894 | if (!state->host) | |
895 | { | |
896 | if (!dh_server_params) | |
897 | { | |
898 | rc = init_server_dh(); | |
899 | if (rc != OK) return rc; | |
900 | } | |
901 | gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); | |
902 | } | |
903 | ||
904 | /* Link the credentials to the session. */ | |
905 | ||
906 | rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); | |
907 | exim_gnutls_err_check(US"gnutls_credentials_set"); | |
908 | ||
909 | return OK; | |
910 | } | |
911 | ||
059ec3d9 | 912 | /************************************************* |
17c76198 | 913 | * Initialize for GnuTLS * |
059ec3d9 PH |
914 | *************************************************/ |
915 | ||
17c76198 PP |
916 | /* Called from both server and client code. In the case of a server, errors |
917 | before actual TLS negotiation return DEFER. | |
059ec3d9 PH |
918 | |
919 | Arguments: | |
17c76198 PP |
920 | host connected host, if client; NULL if server |
921 | certificate certificate file | |
922 | privatekey private key file | |
923 | sni TLS SNI to send, sometimes when client; else NULL | |
924 | cas CA certs file | |
925 | crl CRL file | |
926 | require_ciphers tls_require_ciphers setting | |
817d9f57 | 927 | caller_state returned state-info structure |
059ec3d9 | 928 | |
17c76198 | 929 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
930 | */ |
931 | ||
17c76198 PP |
932 | static int |
933 | tls_init( | |
934 | const host_item *host, | |
935 | const uschar *certificate, | |
936 | const uschar *privatekey, | |
937 | const uschar *sni, | |
938 | const uschar *cas, | |
939 | const uschar *crl, | |
940 | const uschar *require_ciphers, | |
941 | exim_gnutls_state_st **caller_state) | |
059ec3d9 | 942 | { |
17c76198 PP |
943 | exim_gnutls_state_st *state; |
944 | int rc; | |
945 | size_t sz; | |
946 | const char *errpos; | |
947 | uschar *p; | |
948 | BOOL want_default_priorities; | |
949 | ||
950 | if (!exim_gnutls_base_init_done) | |
059ec3d9 | 951 | { |
17c76198 PP |
952 | DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); |
953 | ||
a5f239e4 PP |
954 | #ifdef HAVE_GNUTLS_PKCS11 |
955 | /* By default, gnutls_global_init will init PKCS11 support in auto mode, | |
956 | which loads modules from a config file, which sounds good and may be wanted | |
957 | by some sysadmin, but also means in common configurations that GNOME keyring | |
958 | environment variables are used and so breaks for users calling mailq. | |
959 | To prevent this, we init PKCS11 first, which is the documented approach. */ | |
2519e60d | 960 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
961 | { |
962 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
963 | exim_gnutls_err_check(US"gnutls_pkcs11_init"); | |
964 | } | |
965 | #endif | |
966 | ||
17c76198 PP |
967 | rc = gnutls_global_init(); |
968 | exim_gnutls_err_check(US"gnutls_global_init"); | |
969 | ||
970 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 | |
971 | DEBUG(D_tls) | |
059ec3d9 | 972 | { |
17c76198 PP |
973 | gnutls_global_set_log_function(exim_gnutls_logger_cb); |
974 | /* arbitrarily chosen level; bump upto 9 for more */ | |
975 | gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); | |
059ec3d9 | 976 | } |
17c76198 PP |
977 | #endif |
978 | ||
979 | exim_gnutls_base_init_done = TRUE; | |
059ec3d9 | 980 | } |
059ec3d9 | 981 | |
17c76198 PP |
982 | if (host) |
983 | { | |
984 | state = &state_client; | |
985 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 986 | state->tlsp = &tls_out; |
17c76198 PP |
987 | DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); |
988 | rc = gnutls_init(&state->session, GNUTLS_CLIENT); | |
989 | } | |
990 | else | |
991 | { | |
992 | state = &state_server; | |
993 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); | |
817d9f57 | 994 | state->tlsp = &tls_in; |
17c76198 PP |
995 | DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); |
996 | rc = gnutls_init(&state->session, GNUTLS_SERVER); | |
997 | } | |
998 | exim_gnutls_err_check(US"gnutls_init"); | |
059ec3d9 | 999 | |
17c76198 | 1000 | state->host = host; |
059ec3d9 | 1001 | |
17c76198 PP |
1002 | state->tls_certificate = certificate; |
1003 | state->tls_privatekey = privatekey; | |
5779e6aa | 1004 | state->tls_require_ciphers = require_ciphers; |
17c76198 PP |
1005 | state->tls_sni = sni; |
1006 | state->tls_verify_certificates = cas; | |
1007 | state->tls_crl = crl; | |
059ec3d9 | 1008 | |
17c76198 PP |
1009 | /* This handles the variables that might get re-expanded after TLS SNI; |
1010 | that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ | |
059ec3d9 | 1011 | |
17c76198 PP |
1012 | DEBUG(D_tls) |
1013 | debug_printf("Expanding various TLS configuration options for session credentials.\n"); | |
1014 | rc = tls_expand_session_files(state); | |
1015 | if (rc != OK) return rc; | |
059ec3d9 | 1016 | |
1365611d PP |
1017 | /* These are all other parts of the x509_cred handling, since SNI in GnuTLS |
1018 | requires a new structure afterwards. */ | |
83da1223 | 1019 | |
1365611d PP |
1020 | rc = tls_set_remaining_x509(state); |
1021 | if (rc != OK) return rc; | |
83da1223 | 1022 | |
17c76198 PP |
1023 | /* set SNI in client, only */ |
1024 | if (host) | |
1025 | { | |
a5f239e4 | 1026 | if (!expand_check(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni)) |
17c76198 PP |
1027 | return DEFER; |
1028 | if (state->exp_tls_sni && *state->exp_tls_sni) | |
1029 | { | |
1030 | DEBUG(D_tls) | |
1031 | debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); | |
1032 | sz = Ustrlen(state->exp_tls_sni); | |
1033 | rc = gnutls_server_name_set(state->session, | |
1034 | GNUTLS_NAME_DNS, state->exp_tls_sni, sz); | |
1035 | exim_gnutls_err_check(US"gnutls_server_name_set"); | |
1036 | } | |
1037 | } | |
1038 | else if (state->tls_sni) | |
1039 | DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ | |
1040 | "have an SNI set for a client [%s]\n", state->tls_sni); | |
83da1223 | 1041 | |
17c76198 | 1042 | /* This is the priority string support, |
42bfef1e | 1043 | http://www.gnutls.org/manual/html_node/Priority-Strings.html |
17c76198 PP |
1044 | and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. |
1045 | This was backwards incompatible, but means Exim no longer needs to track | |
1046 | all algorithms and provide string forms for them. */ | |
83da1223 | 1047 | |
17c76198 | 1048 | want_default_priorities = TRUE; |
83da1223 | 1049 | |
17c76198 | 1050 | if (state->tls_require_ciphers && *state->tls_require_ciphers) |
83da1223 | 1051 | { |
17c76198 PP |
1052 | if (!expand_check_tlsvar(tls_require_ciphers)) |
1053 | return DEFER; | |
1054 | if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) | |
83da1223 | 1055 | { |
17c76198 PP |
1056 | DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", |
1057 | state->exp_tls_require_ciphers); | |
1058 | ||
1059 | rc = gnutls_priority_init(&state->priority_cache, | |
1060 | CS state->exp_tls_require_ciphers, &errpos); | |
1061 | want_default_priorities = FALSE; | |
1062 | p = state->exp_tls_require_ciphers; | |
83da1223 PH |
1063 | } |
1064 | } | |
17c76198 PP |
1065 | if (want_default_priorities) |
1066 | { | |
83e2f8a2 PP |
1067 | DEBUG(D_tls) |
1068 | debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", | |
1069 | exim_default_gnutls_priority); | |
17c76198 PP |
1070 | rc = gnutls_priority_init(&state->priority_cache, |
1071 | exim_default_gnutls_priority, &errpos); | |
1072 | p = US exim_default_gnutls_priority; | |
1073 | } | |
83da1223 | 1074 | |
17c76198 PP |
1075 | exim_gnutls_err_check(string_sprintf( |
1076 | "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", | |
1077 | p, errpos - CS p, errpos)); | |
1078 | ||
1079 | rc = gnutls_priority_set(state->session, state->priority_cache); | |
1080 | exim_gnutls_err_check(US"gnutls_priority_set"); | |
1081 | ||
1082 | gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); | |
1083 | ||
1084 | /* Reduce security in favour of increased compatibility, if the admin | |
1085 | decides to make that trade-off. */ | |
1086 | if (gnutls_compat_mode) | |
83da1223 | 1087 | { |
17c76198 PP |
1088 | #if LIBGNUTLS_VERSION_NUMBER >= 0x020104 |
1089 | DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); | |
1090 | gnutls_session_enable_compatibility_mode(state->session); | |
1091 | #else | |
1092 | DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); | |
1093 | #endif | |
83da1223 PH |
1094 | } |
1095 | ||
17c76198 | 1096 | *caller_state = state; |
17c76198 | 1097 | return OK; |
83da1223 PH |
1098 | } |
1099 | ||
1100 | ||
1101 | ||
1102 | ||
059ec3d9 | 1103 | /************************************************* |
17c76198 | 1104 | * Extract peer information * |
059ec3d9 PH |
1105 | *************************************************/ |
1106 | ||
17c76198 | 1107 | /* Called from both server and client code. |
4fe99a6c PP |
1108 | Only this is allowed to set state->peerdn and state->have_set_peerdn |
1109 | and we use that to detect double-calls. | |
059ec3d9 | 1110 | |
75fe387d PP |
1111 | NOTE: the state blocks last while the TLS connection is up, which is fine |
1112 | for logging in the server side, but for the client side, we log after teardown | |
1113 | in src/deliver.c. While the session is up, we can twist about states and | |
1114 | repoint tls_* globals, but those variables used for logging or other variable | |
1115 | expansion that happens _after_ delivery need to have a longer life-time. | |
1116 | ||
1117 | So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from | |
1118 | doing this more than once per generation of a state context. We set them in | |
1119 | the state context, and repoint tls_* to them. After the state goes away, the | |
1120 | tls_* copies of the pointers remain valid and client delivery logging is happy. | |
1121 | ||
1122 | tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues | |
1123 | don't apply. | |
1124 | ||
059ec3d9 | 1125 | Arguments: |
17c76198 | 1126 | state exim_gnutls_state_st * |
059ec3d9 | 1127 | |
17c76198 | 1128 | Returns: OK/DEFER/FAIL |
059ec3d9 PH |
1129 | */ |
1130 | ||
17c76198 PP |
1131 | static int |
1132 | peer_status(exim_gnutls_state_st *state) | |
059ec3d9 | 1133 | { |
75fe387d | 1134 | uschar cipherbuf[256]; |
17c76198 | 1135 | const gnutls_datum *cert_list; |
75fe387d | 1136 | int old_pool, rc; |
17c76198 | 1137 | unsigned int cert_list_size = 0; |
4fe99a6c PP |
1138 | gnutls_protocol_t protocol; |
1139 | gnutls_cipher_algorithm_t cipher; | |
1140 | gnutls_kx_algorithm_t kx; | |
1141 | gnutls_mac_algorithm_t mac; | |
17c76198 PP |
1142 | gnutls_certificate_type_t ct; |
1143 | gnutls_x509_crt_t crt; | |
4fe99a6c | 1144 | uschar *p, *dn_buf; |
17c76198 | 1145 | size_t sz; |
059ec3d9 | 1146 | |
4fe99a6c | 1147 | if (state->have_set_peerdn) |
17c76198 | 1148 | return OK; |
4fe99a6c | 1149 | state->have_set_peerdn = TRUE; |
059ec3d9 | 1150 | |
4fe99a6c | 1151 | state->peerdn = NULL; |
059ec3d9 | 1152 | |
4fe99a6c PP |
1153 | /* tls_cipher */ |
1154 | cipher = gnutls_cipher_get(state->session); | |
1155 | protocol = gnutls_protocol_get_version(state->session); | |
1156 | mac = gnutls_mac_get(state->session); | |
1157 | kx = gnutls_kx_get(state->session); | |
1158 | ||
75fe387d | 1159 | string_format(cipherbuf, sizeof(cipherbuf), |
4fe99a6c PP |
1160 | "%s:%s:%d", |
1161 | gnutls_protocol_get_name(protocol), | |
1162 | gnutls_cipher_suite_get_name(kx, cipher, mac), | |
1163 | (int) gnutls_cipher_get_key_size(cipher) * 8); | |
1164 | ||
1165 | /* I don't see a way that spaces could occur, in the current GnuTLS | |
1166 | code base, but it was a concern in the old code and perhaps older GnuTLS | |
1167 | releases did return "TLS 1.0"; play it safe, just in case. */ | |
75fe387d | 1168 | for (p = cipherbuf; *p != '\0'; ++p) |
4fe99a6c PP |
1169 | if (isspace(*p)) |
1170 | *p = '-'; | |
75fe387d PP |
1171 | old_pool = store_pool; |
1172 | store_pool = POOL_PERM; | |
1173 | state->ciphersuite = string_copy(cipherbuf); | |
1174 | store_pool = old_pool; | |
817d9f57 | 1175 | state->tlsp->cipher = state->ciphersuite; |
4fe99a6c PP |
1176 | |
1177 | /* tls_peerdn */ | |
17c76198 | 1178 | cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); |
83da1223 | 1179 | |
17c76198 PP |
1180 | if (cert_list == NULL || cert_list_size == 0) |
1181 | { | |
17c76198 PP |
1182 | DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", |
1183 | cert_list, cert_list_size); | |
1184 | if (state->verify_requirement == VERIFY_REQUIRED) | |
1185 | return tls_error(US"certificate verification failed", | |
1186 | "no certificate received from peer", state->host); | |
1187 | return OK; | |
1188 | } | |
059ec3d9 | 1189 | |
17c76198 PP |
1190 | ct = gnutls_certificate_type_get(state->session); |
1191 | if (ct != GNUTLS_CRT_X509) | |
059ec3d9 | 1192 | { |
17c76198 | 1193 | const char *ctn = gnutls_certificate_type_get_name(ct); |
17c76198 PP |
1194 | DEBUG(D_tls) |
1195 | debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); | |
1196 | if (state->verify_requirement == VERIFY_REQUIRED) | |
1197 | return tls_error(US"certificate verification not possible, unhandled type", | |
1198 | ctn, state->host); | |
1199 | return OK; | |
83da1223 | 1200 | } |
059ec3d9 | 1201 | |
17c76198 PP |
1202 | #define exim_gnutls_peer_err(Label) do { \ |
1203 | if (rc != GNUTLS_E_SUCCESS) { \ | |
1204 | DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \ | |
1205 | if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \ | |
1206 | return OK; } } while (0) | |
1207 | ||
1208 | rc = gnutls_x509_crt_init(&crt); | |
1209 | exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)"); | |
1210 | ||
1211 | rc = gnutls_x509_crt_import(crt, &cert_list[0], GNUTLS_X509_FMT_DER); | |
1212 | exim_gnutls_peer_err(US"failed to import certificate [gnutls_x509_crt_import(cert 0)]"); | |
1213 | sz = 0; | |
1214 | rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); | |
1215 | if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) | |
83da1223 | 1216 | { |
17c76198 PP |
1217 | exim_gnutls_peer_err(US"getting size for cert DN failed"); |
1218 | return FAIL; /* should not happen */ | |
059ec3d9 | 1219 | } |
17c76198 PP |
1220 | dn_buf = store_get_perm(sz); |
1221 | rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); | |
1222 | exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); | |
1223 | state->peerdn = dn_buf; | |
1224 | ||
1225 | return OK; | |
1226 | #undef exim_gnutls_peer_err | |
1227 | } | |
059ec3d9 | 1228 | |
059ec3d9 | 1229 | |
059ec3d9 | 1230 | |
059ec3d9 | 1231 | |
17c76198 PP |
1232 | /************************************************* |
1233 | * Verify peer certificate * | |
1234 | *************************************************/ | |
059ec3d9 | 1235 | |
17c76198 PP |
1236 | /* Called from both server and client code. |
1237 | *Should* be using a callback registered with | |
1238 | gnutls_certificate_set_verify_function() to fail the handshake if we dislike | |
1239 | the peer information, but that's too new for some OSes. | |
059ec3d9 | 1240 | |
17c76198 PP |
1241 | Arguments: |
1242 | state exim_gnutls_state_st * | |
1243 | error where to put an error message | |
059ec3d9 | 1244 | |
17c76198 PP |
1245 | Returns: |
1246 | FALSE if the session should be rejected | |
1247 | TRUE if the cert is okay or we just don't care | |
1248 | */ | |
059ec3d9 | 1249 | |
17c76198 PP |
1250 | static BOOL |
1251 | verify_certificate(exim_gnutls_state_st *state, const char **error) | |
1252 | { | |
1253 | int rc; | |
1254 | unsigned int verify; | |
1255 | ||
1256 | *error = NULL; | |
1257 | ||
0a92f87f | 1258 | if ((rc = peer_status(state)) != OK) |
e6060e2c | 1259 | { |
17c76198 | 1260 | verify = GNUTLS_CERT_INVALID; |
0a92f87f | 1261 | *error = "certificate not supplied"; |
17c76198 PP |
1262 | } |
1263 | else | |
17c76198 | 1264 | rc = gnutls_certificate_verify_peers2(state->session, &verify); |
e6060e2c | 1265 | |
17c76198 PP |
1266 | /* Handle the result of verification. INVALID seems to be set as well |
1267 | as REVOKED, but leave the test for both. */ | |
059ec3d9 | 1268 | |
0a92f87f | 1269 | if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) |
17c76198 PP |
1270 | { |
1271 | state->peer_cert_verified = FALSE; | |
0a92f87f JH |
1272 | if (!*error) |
1273 | *error = verify & GNUTLS_CERT_REVOKED | |
1274 | ? "certificate revoked" : "certificate invalid"; | |
059ec3d9 | 1275 | |
17c76198 PP |
1276 | DEBUG(D_tls) |
1277 | debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", | |
4fe99a6c | 1278 | *error, state->peerdn ? state->peerdn : US"<unset>"); |
059ec3d9 | 1279 | |
17c76198 PP |
1280 | if (state->verify_requirement == VERIFY_REQUIRED) |
1281 | { | |
1282 | gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
1283 | return FALSE; | |
1284 | } | |
1285 | DEBUG(D_tls) | |
4789da3a | 1286 | debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); |
17c76198 PP |
1287 | } |
1288 | else | |
1289 | { | |
1290 | state->peer_cert_verified = TRUE; | |
4fe99a6c PP |
1291 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", |
1292 | state->peerdn ? state->peerdn : US"<unset>"); | |
17c76198 | 1293 | } |
059ec3d9 | 1294 | |
817d9f57 | 1295 | state->tlsp->peerdn = state->peerdn; |
059ec3d9 | 1296 | |
17c76198 PP |
1297 | return TRUE; |
1298 | } | |
059ec3d9 | 1299 | |
17c76198 PP |
1300 | |
1301 | ||
1302 | ||
1303 | /* ------------------------------------------------------------------------ */ | |
1304 | /* Callbacks */ | |
1305 | ||
1306 | /* Logging function which can be registered with | |
1307 | * gnutls_global_set_log_function() | |
1308 | * gnutls_global_set_log_level() 0..9 | |
1309 | */ | |
af3498d6 | 1310 | #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 |
059ec3d9 | 1311 | static void |
17c76198 | 1312 | exim_gnutls_logger_cb(int level, const char *message) |
059ec3d9 | 1313 | { |
8c79eebf PP |
1314 | size_t len = strlen(message); |
1315 | if (len < 1) | |
1316 | { | |
1317 | DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); | |
1318 | return; | |
1319 | } | |
1320 | DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, | |
1321 | message[len-1] == '\n' ? "" : "\n"); | |
17c76198 | 1322 | } |
af3498d6 | 1323 | #endif |
059ec3d9 | 1324 | |
059ec3d9 | 1325 | |
17c76198 PP |
1326 | /* Called after client hello, should handle SNI work. |
1327 | This will always set tls_sni (state->received_sni) if available, | |
1328 | and may trigger presenting different certificates, | |
1329 | if state->trigger_sni_changes is TRUE. | |
059ec3d9 | 1330 | |
17c76198 PP |
1331 | Should be registered with |
1332 | gnutls_handshake_set_post_client_hello_function() | |
059ec3d9 | 1333 | |
17c76198 PP |
1334 | "This callback must return 0 on success or a gnutls error code to terminate the |
1335 | handshake.". | |
059ec3d9 | 1336 | |
17c76198 PP |
1337 | For inability to get SNI information, we return 0. |
1338 | We only return non-zero if re-setup failed. | |
817d9f57 | 1339 | Only used for server-side TLS. |
17c76198 | 1340 | */ |
44bbabb5 | 1341 | |
17c76198 PP |
1342 | static int |
1343 | exim_sni_handling_cb(gnutls_session_t session) | |
1344 | { | |
1345 | char sni_name[MAX_HOST_LEN]; | |
1346 | size_t data_len = MAX_HOST_LEN; | |
817d9f57 | 1347 | exim_gnutls_state_st *state = &state_server; |
17c76198 PP |
1348 | unsigned int sni_type; |
1349 | int rc, old_pool; | |
1350 | ||
1351 | rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); | |
b34fc30c PP |
1352 | if (rc != GNUTLS_E_SUCCESS) |
1353 | { | |
1354 | DEBUG(D_tls) { | |
1355 | if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) | |
1356 | debug_printf("TLS: no SNI presented in handshake.\n"); | |
1357 | else | |
1358 | debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", | |
1359 | gnutls_strerror(rc), rc); | |
1360 | }; | |
1361 | return 0; | |
1362 | } | |
1363 | ||
17c76198 PP |
1364 | if (sni_type != GNUTLS_NAME_DNS) |
1365 | { | |
1366 | DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); | |
1367 | return 0; | |
1368 | } | |
44bbabb5 | 1369 | |
17c76198 PP |
1370 | /* We now have a UTF-8 string in sni_name */ |
1371 | old_pool = store_pool; | |
1372 | store_pool = POOL_PERM; | |
1373 | state->received_sni = string_copyn(US sni_name, data_len); | |
1374 | store_pool = old_pool; | |
1375 | ||
1376 | /* We set this one now so that variable expansions below will work */ | |
817d9f57 | 1377 | state->tlsp->sni = state->received_sni; |
17c76198 PP |
1378 | |
1379 | DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, | |
1380 | state->trigger_sni_changes ? "" : " (unused for certificate selection)"); | |
1381 | ||
1382 | if (!state->trigger_sni_changes) | |
1383 | return 0; | |
1384 | ||
1385 | rc = tls_expand_session_files(state); | |
1386 | if (rc != OK) | |
1387 | { | |
1388 | /* If the setup of certs/etc failed before handshake, TLS would not have | |
1389 | been offered. The best we can do now is abort. */ | |
1390 | return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1391 | } | |
1392 | ||
1365611d PP |
1393 | rc = tls_set_remaining_x509(state); |
1394 | if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; | |
1395 | ||
1396 | return 0; | |
059ec3d9 PH |
1397 | } |
1398 | ||
1399 | ||
1400 | ||
17c76198 PP |
1401 | |
1402 | /* ------------------------------------------------------------------------ */ | |
1403 | /* Exported functions */ | |
1404 | ||
1405 | ||
1406 | ||
1407 | ||
059ec3d9 PH |
1408 | /************************************************* |
1409 | * Start a TLS session in a server * | |
1410 | *************************************************/ | |
1411 | ||
1412 | /* This is called when Exim is running as a server, after having received | |
1413 | the STARTTLS command. It must respond to that command, and then negotiate | |
1414 | a TLS session. | |
1415 | ||
1416 | Arguments: | |
83da1223 | 1417 | require_ciphers list of allowed ciphers or NULL |
059ec3d9 PH |
1418 | |
1419 | Returns: OK on success | |
1420 | DEFER for errors before the start of the negotiation | |
1421 | FAIL for errors during the negotation; the server can't | |
1422 | continue running. | |
1423 | */ | |
1424 | ||
1425 | int | |
17c76198 | 1426 | tls_server_start(const uschar *require_ciphers) |
059ec3d9 PH |
1427 | { |
1428 | int rc; | |
7199e1ee | 1429 | const char *error; |
17c76198 | 1430 | exim_gnutls_state_st *state = NULL; |
059ec3d9 PH |
1431 | |
1432 | /* Check for previous activation */ | |
817d9f57 | 1433 | if (tls_in.active >= 0) |
059ec3d9 | 1434 | { |
17c76198 | 1435 | tls_error(US"STARTTLS received after TLS started", "", NULL); |
059ec3d9 PH |
1436 | smtp_printf("554 Already in TLS\r\n"); |
1437 | return FAIL; | |
1438 | } | |
1439 | ||
1440 | /* Initialize the library. If it fails, it will already have logged the error | |
1441 | and sent an SMTP response. */ | |
1442 | ||
17c76198 | 1443 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); |
059ec3d9 | 1444 | |
17c76198 PP |
1445 | rc = tls_init(NULL, tls_certificate, tls_privatekey, |
1446 | NULL, tls_verify_certificates, tls_crl, | |
1447 | require_ciphers, &state); | |
059ec3d9 PH |
1448 | if (rc != OK) return rc; |
1449 | ||
059ec3d9 PH |
1450 | /* If this is a host for which certificate verification is mandatory or |
1451 | optional, set up appropriately. */ | |
1452 | ||
059ec3d9 | 1453 | if (verify_check_host(&tls_verify_hosts) == OK) |
17c76198 PP |
1454 | { |
1455 | DEBUG(D_tls) debug_printf("TLS: a client certificate will be required.\n"); | |
1456 | state->verify_requirement = VERIFY_REQUIRED; | |
1457 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1458 | } | |
059ec3d9 | 1459 | else if (verify_check_host(&tls_try_verify_hosts) == OK) |
17c76198 PP |
1460 | { |
1461 | DEBUG(D_tls) debug_printf("TLS: a client certificate will be requested but not required.\n"); | |
1462 | state->verify_requirement = VERIFY_OPTIONAL; | |
1463 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); | |
1464 | } | |
1465 | else | |
1466 | { | |
1467 | DEBUG(D_tls) debug_printf("TLS: a client certificate will not be requested.\n"); | |
1468 | state->verify_requirement = VERIFY_NONE; | |
1469 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
1470 | } | |
059ec3d9 | 1471 | |
17c76198 PP |
1472 | /* Register SNI handling; always, even if not in tls_certificate, so that the |
1473 | expansion variable $tls_sni is always available. */ | |
059ec3d9 | 1474 | |
17c76198 PP |
1475 | gnutls_handshake_set_post_client_hello_function(state->session, |
1476 | exim_sni_handling_cb); | |
059ec3d9 PH |
1477 | |
1478 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
1479 | on connection, where outputting anything now upsets the clients and tends to | |
1480 | make them disconnect. We need to have an explicit fflush() here, to force out | |
1481 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
1482 | mode, the fflush() happens when smtp_getc() is called. */ | |
1483 | ||
817d9f57 | 1484 | if (!state->tlsp->on_connect) |
059ec3d9 PH |
1485 | { |
1486 | smtp_printf("220 TLS go ahead\r\n"); | |
817d9f57 | 1487 | fflush(smtp_out); /*XXX JGH */ |
059ec3d9 PH |
1488 | } |
1489 | ||
1490 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
1491 | that the GnuTLS library doesn't. */ | |
1492 | ||
17c76198 PP |
1493 | gnutls_transport_set_ptr2(state->session, |
1494 | (gnutls_transport_ptr)fileno(smtp_in), | |
1495 | (gnutls_transport_ptr)fileno(smtp_out)); | |
1496 | state->fd_in = fileno(smtp_in); | |
1497 | state->fd_out = fileno(smtp_out); | |
059ec3d9 PH |
1498 | |
1499 | sigalrm_seen = FALSE; | |
1500 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 PP |
1501 | do |
1502 | { | |
1503 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1504 | } while ((rc == GNUTLS_E_AGAIN) || |
1505 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1506 | alarm(0); |
1507 | ||
17c76198 | 1508 | if (rc != GNUTLS_E_SUCCESS) |
059ec3d9 | 1509 | { |
17c76198 PP |
1510 | tls_error(US"gnutls_handshake", |
1511 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); | |
059ec3d9 PH |
1512 | /* It seems that, except in the case of a timeout, we have to close the |
1513 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
1514 | until the server times out. */ | |
1515 | ||
1516 | if (!sigalrm_seen) | |
1517 | { | |
f1e894f3 PH |
1518 | (void)fclose(smtp_out); |
1519 | (void)fclose(smtp_in); | |
059ec3d9 PH |
1520 | } |
1521 | ||
1522 | return FAIL; | |
1523 | } | |
1524 | ||
1525 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
1526 | ||
17c76198 PP |
1527 | /* Verify after the fact */ |
1528 | ||
1529 | if (state->verify_requirement != VERIFY_NONE) | |
059ec3d9 | 1530 | { |
17c76198 PP |
1531 | if (!verify_certificate(state, &error)) |
1532 | { | |
1533 | if (state->verify_requirement == VERIFY_OPTIONAL) | |
1534 | { | |
1535 | DEBUG(D_tls) | |
1536 | debug_printf("TLS: continuing on only because verification was optional, after: %s\n", | |
1537 | error); | |
1538 | } | |
1539 | else | |
1540 | { | |
1541 | tls_error(US"certificate verification failed", error, NULL); | |
1542 | return FAIL; | |
1543 | } | |
1544 | } | |
059ec3d9 PH |
1545 | } |
1546 | ||
17c76198 PP |
1547 | /* Figure out peer DN, and if authenticated, etc. */ |
1548 | ||
1549 | rc = peer_status(state); | |
1550 | if (rc != OK) return rc; | |
1551 | ||
1552 | /* Sets various Exim expansion variables; always safe within server */ | |
1553 | ||
817d9f57 | 1554 | extract_exim_vars_from_tls_state(state, TRUE); |
059ec3d9 PH |
1555 | |
1556 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
1557 | and initialize appropriately. */ | |
1558 | ||
17c76198 | 1559 | state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); |
059ec3d9 PH |
1560 | |
1561 | receive_getc = tls_getc; | |
1562 | receive_ungetc = tls_ungetc; | |
1563 | receive_feof = tls_feof; | |
1564 | receive_ferror = tls_ferror; | |
58eb016e | 1565 | receive_smtp_buffered = tls_smtp_buffered; |
059ec3d9 | 1566 | |
059ec3d9 PH |
1567 | return OK; |
1568 | } | |
1569 | ||
1570 | ||
1571 | ||
1572 | ||
1573 | /************************************************* | |
1574 | * Start a TLS session in a client * | |
1575 | *************************************************/ | |
1576 | ||
1577 | /* Called from the smtp transport after STARTTLS has been accepted. | |
1578 | ||
1579 | Arguments: | |
1580 | fd the fd of the connection | |
1581 | host connected host (for messages) | |
83da1223 | 1582 | addr the first address (not used) |
059ec3d9 PH |
1583 | certificate certificate file |
1584 | privatekey private key file | |
3f0945ff | 1585 | sni TLS SNI to send to remote host |
059ec3d9 PH |
1586 | verify_certs file for certificate verify |
1587 | verify_crl CRL for verify | |
83da1223 | 1588 | require_ciphers list of allowed ciphers or NULL |
2b4a568d | 1589 | hosts_require_ocsp hosts for which to request certificate-status (OCSP) |
54c90be1 | 1590 | dh_min_bits minimum number of bits acceptable in server's DH prime |
059ec3d9 | 1591 | timeout startup timeout |
2b4a568d JH |
1592 | verify_hosts mandatory client verification |
1593 | try_verify_hosts optional client verification | |
059ec3d9 PH |
1594 | |
1595 | Returns: OK/DEFER/FAIL (because using common functions), | |
1596 | but for a client, DEFER and FAIL have the same meaning | |
1597 | */ | |
1598 | ||
1599 | int | |
17c76198 | 1600 | tls_client_start(int fd, host_item *host, |
f5d78688 | 1601 | address_item *addr ARG_UNUSED, |
17c76198 PP |
1602 | uschar *certificate, uschar *privatekey, uschar *sni, |
1603 | uschar *verify_certs, uschar *verify_crl, | |
f5d78688 JH |
1604 | uschar *require_ciphers, |
1605 | #ifdef EXPERIMENTAL_OCSP | |
2b4a568d | 1606 | uschar *hosts_require_ocsp, |
f5d78688 | 1607 | #endif |
a63be306 WB |
1608 | int dh_min_bits, int timeout, |
1609 | uschar *verify_hosts, uschar *try_verify_hosts) | |
059ec3d9 | 1610 | { |
059ec3d9 | 1611 | int rc; |
17c76198 PP |
1612 | const char *error; |
1613 | exim_gnutls_state_st *state = NULL; | |
2b4a568d JH |
1614 | #ifdef EXPERIMENTAL_OCSP |
1615 | BOOL require_ocsp = verify_check_this_host(&hosts_require_ocsp, | |
1616 | NULL, host->name, host->address, NULL) == OK; | |
1617 | #endif | |
059ec3d9 | 1618 | |
17c76198 | 1619 | DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); |
059ec3d9 | 1620 | |
2b4a568d JH |
1621 | if ((rc = tls_init(host, certificate, privatekey, |
1622 | sni, verify_certs, verify_crl, require_ciphers, &state)) != OK) | |
1623 | return rc; | |
059ec3d9 | 1624 | |
54c90be1 PP |
1625 | if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) |
1626 | { | |
1627 | DEBUG(D_tls) | |
1628 | debug_printf("WARNING: tls_dh_min_bits far too low, clamping %d up to %d\n", | |
1629 | dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); | |
1630 | dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; | |
1631 | } | |
1632 | ||
1633 | DEBUG(D_tls) debug_printf("Setting D-H prime minimum acceptable bits to %d\n", | |
1634 | dh_min_bits); | |
1635 | gnutls_dh_set_prime_bits(state->session, dh_min_bits); | |
83da1223 | 1636 | |
2b4a568d JH |
1637 | /* Stick to the old behaviour for compatibility if tls_verify_certificates is |
1638 | set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only | |
1639 | the specified host patterns if one of them is defined */ | |
1640 | ||
1641 | if (( state->exp_tls_verify_certificates | |
1642 | && !verify_hosts | |
1643 | && !try_verify_hosts | |
1644 | ) | |
1645 | || | |
1646 | verify_check_host(&verify_hosts) == OK | |
1647 | ) | |
17c76198 | 1648 | { |
52f93eed WB |
1649 | DEBUG(D_tls) debug_printf("TLS: server certificate verification required.\n"); |
1650 | state->verify_requirement = VERIFY_REQUIRED; | |
1651 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); | |
1652 | } | |
1653 | else if (verify_check_host(&try_verify_hosts) == OK) | |
1654 | { | |
1655 | DEBUG(D_tls) debug_printf("TLS: server certificate verification optional.\n"); | |
1656 | state->verify_requirement = VERIFY_OPTIONAL; | |
17c76198 PP |
1657 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); |
1658 | } | |
1659 | else | |
1660 | { | |
52f93eed WB |
1661 | DEBUG(D_tls) debug_printf("TLS: server certificate verification not required.\n"); |
1662 | state->verify_requirement = VERIFY_NONE; | |
1663 | gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); | |
17c76198 | 1664 | } |
059ec3d9 | 1665 | |
2b4a568d JH |
1666 | #ifdef EXPERIMENTAL_OCSP /* since GnuTLS 3.1.3 */ |
1667 | if (require_ocsp && | |
1668 | (rc = gnutls_ocsp_status_request_enable_client(state->session, NULL, 0, NULL)) | |
1669 | != OK) | |
1670 | return tls_error(US"cert-status-req", gnutls_strerror(rc), state->host); | |
1671 | #endif | |
1672 | ||
17c76198 PP |
1673 | gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)fd); |
1674 | state->fd_in = fd; | |
1675 | state->fd_out = fd; | |
059ec3d9 PH |
1676 | |
1677 | /* There doesn't seem to be a built-in timeout on connection. */ | |
1678 | ||
1679 | sigalrm_seen = FALSE; | |
1680 | alarm(timeout); | |
17c76198 PP |
1681 | do |
1682 | { | |
1683 | rc = gnutls_handshake(state->session); | |
619b2b25 PP |
1684 | } while ((rc == GNUTLS_E_AGAIN) || |
1685 | (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); | |
059ec3d9 PH |
1686 | alarm(0); |
1687 | ||
4fe99a6c PP |
1688 | if (rc != GNUTLS_E_SUCCESS) |
1689 | return tls_error(US"gnutls_handshake", | |
1690 | sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); | |
1691 | ||
17c76198 | 1692 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); |
059ec3d9 | 1693 | |
17c76198 | 1694 | /* Verify late */ |
059ec3d9 | 1695 | |
17c76198 PP |
1696 | if (state->verify_requirement != VERIFY_NONE && |
1697 | !verify_certificate(state, &error)) | |
1698 | return tls_error(US"certificate verification failed", error, state->host); | |
059ec3d9 | 1699 | |
2b4a568d JH |
1700 | #ifdef EXPERIMENTAL_OCSP |
1701 | if (require_ocsp) | |
1702 | { | |
1703 | DEBUG(D_tls) | |
1704 | { | |
1705 | gnutls_datum_t stapling; | |
1706 | gnutls_ocsp_resp_t resp; | |
1707 | gnutls_datum_t printed; | |
1708 | if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 | |
1709 | && (rc= gnutls_ocsp_resp_init(&resp)) == 0 | |
1710 | && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 | |
1711 | && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 | |
1712 | ) | |
1713 | { | |
1714 | fprintf(stderr, "%.4096s", printed.data); | |
1715 | gnutls_free(printed.data); | |
1716 | } | |
1717 | else | |
1718 | (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); | |
1719 | } | |
1720 | ||
1721 | fprintf(stderr, "%s: checking ocsp\n", __FUNCTION__); | |
1722 | if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) | |
1723 | return tls_error(US"certificate status check failed", NULL, state->host); | |
1724 | DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); | |
1725 | } | |
1726 | #endif | |
1727 | ||
17c76198 | 1728 | /* Figure out peer DN, and if authenticated, etc. */ |
059ec3d9 | 1729 | |
2b4a568d JH |
1730 | if ((rc = peer_status(state)) != OK) |
1731 | return rc; | |
059ec3d9 | 1732 | |
4fe99a6c | 1733 | /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ |
059ec3d9 | 1734 | |
817d9f57 | 1735 | extract_exim_vars_from_tls_state(state, FALSE); |
059ec3d9 | 1736 | |
059ec3d9 PH |
1737 | return OK; |
1738 | } | |
1739 | ||
1740 | ||
1741 | ||
17c76198 | 1742 | |
059ec3d9 | 1743 | /************************************************* |
17c76198 | 1744 | * Close down a TLS session * |
059ec3d9 PH |
1745 | *************************************************/ |
1746 | ||
17c76198 PP |
1747 | /* This is also called from within a delivery subprocess forked from the |
1748 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1749 | would tamper with the TLS session in the parent process). | |
059ec3d9 | 1750 | |
17c76198 PP |
1751 | Arguments: TRUE if gnutls_bye is to be called |
1752 | Returns: nothing | |
059ec3d9 PH |
1753 | */ |
1754 | ||
17c76198 | 1755 | void |
817d9f57 | 1756 | tls_close(BOOL is_server, BOOL shutdown) |
059ec3d9 | 1757 | { |
817d9f57 | 1758 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1759 | |
389ca47a | 1760 | if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ |
17c76198 PP |
1761 | |
1762 | if (shutdown) | |
1763 | { | |
1764 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1765 | gnutls_bye(state->session, GNUTLS_SHUT_WR); | |
1766 | } | |
1767 | ||
1768 | gnutls_deinit(state->session); | |
1769 | ||
389ca47a | 1770 | state->tlsp->active = -1; |
17c76198 PP |
1771 | memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); |
1772 | ||
1773 | if ((state_server.session == NULL) && (state_client.session == NULL)) | |
1774 | { | |
1775 | gnutls_global_deinit(); | |
1776 | exim_gnutls_base_init_done = FALSE; | |
1777 | } | |
7199e1ee | 1778 | |
059ec3d9 PH |
1779 | } |
1780 | ||
1781 | ||
1782 | ||
17c76198 | 1783 | |
059ec3d9 PH |
1784 | /************************************************* |
1785 | * TLS version of getc * | |
1786 | *************************************************/ | |
1787 | ||
1788 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1789 | it refills the buffer via the GnuTLS reading function. | |
817d9f57 | 1790 | Only used by the server-side TLS. |
059ec3d9 | 1791 | |
17c76198 PP |
1792 | This feeds DKIM and should be used for all message-body reads. |
1793 | ||
059ec3d9 PH |
1794 | Arguments: none |
1795 | Returns: the next character or EOF | |
1796 | */ | |
1797 | ||
1798 | int | |
1799 | tls_getc(void) | |
1800 | { | |
817d9f57 | 1801 | exim_gnutls_state_st *state = &state_server; |
17c76198 | 1802 | if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) |
059ec3d9 | 1803 | { |
17c76198 | 1804 | ssize_t inbytes; |
059ec3d9 | 1805 | |
17c76198 PP |
1806 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", |
1807 | state->session, state->xfer_buffer, ssl_xfer_buffer_size); | |
059ec3d9 PH |
1808 | |
1809 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
17c76198 | 1810 | inbytes = gnutls_record_recv(state->session, state->xfer_buffer, |
059ec3d9 PH |
1811 | ssl_xfer_buffer_size); |
1812 | alarm(0); | |
1813 | ||
1814 | /* A zero-byte return appears to mean that the TLS session has been | |
1815 | closed down, not that the socket itself has been closed down. Revert to | |
1816 | non-TLS handling. */ | |
1817 | ||
1818 | if (inbytes == 0) | |
1819 | { | |
1820 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1821 | ||
1822 | receive_getc = smtp_getc; | |
1823 | receive_ungetc = smtp_ungetc; | |
1824 | receive_feof = smtp_feof; | |
1825 | receive_ferror = smtp_ferror; | |
58eb016e | 1826 | receive_smtp_buffered = smtp_buffered; |
059ec3d9 | 1827 | |
17c76198 PP |
1828 | gnutls_deinit(state->session); |
1829 | state->session = NULL; | |
817d9f57 JH |
1830 | state->tlsp->active = -1; |
1831 | state->tlsp->bits = 0; | |
1832 | state->tlsp->certificate_verified = FALSE; | |
1833 | tls_channelbinding_b64 = NULL; /*XXX JGH */ | |
1834 | state->tlsp->cipher = NULL; | |
1835 | state->tlsp->peerdn = NULL; | |
059ec3d9 PH |
1836 | |
1837 | return smtp_getc(); | |
1838 | } | |
1839 | ||
1840 | /* Handle genuine errors */ | |
1841 | ||
1842 | else if (inbytes < 0) | |
1843 | { | |
17c76198 PP |
1844 | record_io_error(state, (int) inbytes, US"recv", NULL); |
1845 | state->xfer_error = 1; | |
059ec3d9 PH |
1846 | return EOF; |
1847 | } | |
80a47a2c | 1848 | #ifndef DISABLE_DKIM |
17c76198 | 1849 | dkim_exim_verify_feed(state->xfer_buffer, inbytes); |
80a47a2c | 1850 | #endif |
17c76198 PP |
1851 | state->xfer_buffer_hwm = (int) inbytes; |
1852 | state->xfer_buffer_lwm = 0; | |
059ec3d9 PH |
1853 | } |
1854 | ||
059ec3d9 PH |
1855 | /* Something in the buffer; return next uschar */ |
1856 | ||
17c76198 | 1857 | return state->xfer_buffer[state->xfer_buffer_lwm++]; |
059ec3d9 PH |
1858 | } |
1859 | ||
1860 | ||
1861 | ||
17c76198 | 1862 | |
059ec3d9 PH |
1863 | /************************************************* |
1864 | * Read bytes from TLS channel * | |
1865 | *************************************************/ | |
1866 | ||
17c76198 PP |
1867 | /* This does not feed DKIM, so if the caller uses this for reading message body, |
1868 | then the caller must feed DKIM. | |
817d9f57 | 1869 | |
059ec3d9 PH |
1870 | Arguments: |
1871 | buff buffer of data | |
1872 | len size of buffer | |
1873 | ||
1874 | Returns: the number of bytes read | |
1875 | -1 after a failed read | |
1876 | */ | |
1877 | ||
1878 | int | |
817d9f57 | 1879 | tls_read(BOOL is_server, uschar *buff, size_t len) |
059ec3d9 | 1880 | { |
817d9f57 | 1881 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
17c76198 | 1882 | ssize_t inbytes; |
059ec3d9 | 1883 | |
17c76198 PP |
1884 | if (len > INT_MAX) |
1885 | len = INT_MAX; | |
059ec3d9 | 1886 | |
17c76198 PP |
1887 | if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) |
1888 | DEBUG(D_tls) | |
1889 | debug_printf("*** PROBABLY A BUG *** " \ | |
1890 | "tls_read() called with data in the tls_getc() buffer, %d ignored\n", | |
1891 | state->xfer_buffer_hwm - state->xfer_buffer_lwm); | |
1892 | ||
1893 | DEBUG(D_tls) | |
1894 | debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", | |
1895 | state->session, buff, len); | |
1896 | ||
1897 | inbytes = gnutls_record_recv(state->session, buff, len); | |
059ec3d9 PH |
1898 | if (inbytes > 0) return inbytes; |
1899 | if (inbytes == 0) | |
1900 | { | |
1901 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1902 | } | |
17c76198 | 1903 | else record_io_error(state, (int)inbytes, US"recv", NULL); |
059ec3d9 PH |
1904 | |
1905 | return -1; | |
1906 | } | |
1907 | ||
1908 | ||
1909 | ||
17c76198 | 1910 | |
059ec3d9 PH |
1911 | /************************************************* |
1912 | * Write bytes down TLS channel * | |
1913 | *************************************************/ | |
1914 | ||
1915 | /* | |
1916 | Arguments: | |
817d9f57 | 1917 | is_server channel specifier |
059ec3d9 PH |
1918 | buff buffer of data |
1919 | len number of bytes | |
1920 | ||
1921 | Returns: the number of bytes after a successful write, | |
1922 | -1 after a failed write | |
1923 | */ | |
1924 | ||
1925 | int | |
817d9f57 | 1926 | tls_write(BOOL is_server, const uschar *buff, size_t len) |
059ec3d9 | 1927 | { |
17c76198 PP |
1928 | ssize_t outbytes; |
1929 | size_t left = len; | |
817d9f57 | 1930 | exim_gnutls_state_st *state = is_server ? &state_server : &state_client; |
059ec3d9 | 1931 | |
17c76198 | 1932 | DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); |
059ec3d9 PH |
1933 | while (left > 0) |
1934 | { | |
17c76198 PP |
1935 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", |
1936 | buff, left); | |
1937 | outbytes = gnutls_record_send(state->session, buff, left); | |
059ec3d9 | 1938 | |
17c76198 | 1939 | DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); |
059ec3d9 PH |
1940 | if (outbytes < 0) |
1941 | { | |
17c76198 | 1942 | record_io_error(state, outbytes, US"send", NULL); |
059ec3d9 PH |
1943 | return -1; |
1944 | } | |
1945 | if (outbytes == 0) | |
1946 | { | |
17c76198 | 1947 | record_io_error(state, 0, US"send", US"TLS channel closed on write"); |
059ec3d9 PH |
1948 | return -1; |
1949 | } | |
1950 | ||
1951 | left -= outbytes; | |
1952 | buff += outbytes; | |
1953 | } | |
1954 | ||
17c76198 PP |
1955 | if (len > INT_MAX) |
1956 | { | |
1957 | DEBUG(D_tls) | |
1958 | debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", | |
1959 | len); | |
1960 | len = INT_MAX; | |
1961 | } | |
1962 | ||
1963 | return (int) len; | |
059ec3d9 PH |
1964 | } |
1965 | ||
1966 | ||
1967 | ||
17c76198 | 1968 | |
059ec3d9 | 1969 | /************************************************* |
17c76198 | 1970 | * Random number generation * |
059ec3d9 PH |
1971 | *************************************************/ |
1972 | ||
17c76198 PP |
1973 | /* Pseudo-random number generation. The result is not expected to be |
1974 | cryptographically strong but not so weak that someone will shoot themselves | |
1975 | in the foot using it as a nonce in input in some email header scheme or | |
1976 | whatever weirdness they'll twist this into. The result should handle fork() | |
1977 | and avoid repeating sequences. OpenSSL handles that for us. | |
059ec3d9 | 1978 | |
17c76198 PP |
1979 | Arguments: |
1980 | max range maximum | |
1981 | Returns a random number in range [0, max-1] | |
059ec3d9 PH |
1982 | */ |
1983 | ||
af3498d6 | 1984 | #ifdef HAVE_GNUTLS_RND |
17c76198 PP |
1985 | int |
1986 | vaguely_random_number(int max) | |
059ec3d9 | 1987 | { |
17c76198 PP |
1988 | unsigned int r; |
1989 | int i, needed_len; | |
1990 | uschar *p; | |
1991 | uschar smallbuf[sizeof(r)]; | |
1992 | ||
1993 | if (max <= 1) | |
1994 | return 0; | |
1995 | ||
1996 | needed_len = sizeof(r); | |
1997 | /* Don't take 8 times more entropy than needed if int is 8 octets and we were | |
1998 | * asked for a number less than 10. */ | |
1999 | for (r = max, i = 0; r; ++i) | |
2000 | r >>= 1; | |
2001 | i = (i + 7) / 8; | |
2002 | if (i < needed_len) | |
2003 | needed_len = i; | |
2004 | ||
2005 | i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); | |
2006 | if (i < 0) | |
059ec3d9 | 2007 | { |
17c76198 PP |
2008 | DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); |
2009 | return vaguely_random_number_fallback(max); | |
2010 | } | |
2011 | r = 0; | |
2012 | for (p = smallbuf; needed_len; --needed_len, ++p) | |
2013 | { | |
2014 | r *= 256; | |
2015 | r += *p; | |
059ec3d9 PH |
2016 | } |
2017 | ||
17c76198 PP |
2018 | /* We don't particularly care about weighted results; if someone wants |
2019 | * smooth distribution and cares enough then they should submit a patch then. */ | |
2020 | return r % max; | |
059ec3d9 | 2021 | } |
af3498d6 PP |
2022 | #else /* HAVE_GNUTLS_RND */ |
2023 | int | |
2024 | vaguely_random_number(int max) | |
2025 | { | |
2026 | return vaguely_random_number_fallback(max); | |
2027 | } | |
2028 | #endif /* HAVE_GNUTLS_RND */ | |
059ec3d9 | 2029 | |
36f12725 NM |
2030 | |
2031 | ||
2032 | ||
3375e053 PP |
2033 | /************************************************* |
2034 | * Let tls_require_ciphers be checked at startup * | |
2035 | *************************************************/ | |
2036 | ||
2037 | /* The tls_require_ciphers option, if set, must be something which the | |
2038 | library can parse. | |
2039 | ||
2040 | Returns: NULL on success, or error message | |
2041 | */ | |
2042 | ||
2043 | uschar * | |
2044 | tls_validate_require_cipher(void) | |
2045 | { | |
2046 | int rc; | |
2047 | uschar *expciphers = NULL; | |
2048 | gnutls_priority_t priority_cache; | |
2049 | const char *errpos; | |
2050 | ||
2051 | #define validate_check_rc(Label) do { \ | |
2052 | if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ | |
2053 | return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) | |
2054 | #define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) | |
2055 | ||
2056 | if (exim_gnutls_base_init_done) | |
2057 | log_write(0, LOG_MAIN|LOG_PANIC, | |
2058 | "already initialised GnuTLS, Exim developer bug"); | |
2059 | ||
a5f239e4 | 2060 | #ifdef HAVE_GNUTLS_PKCS11 |
2519e60d | 2061 | if (!gnutls_allow_auto_pkcs11) |
a5f239e4 PP |
2062 | { |
2063 | rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); | |
2064 | validate_check_rc(US"gnutls_pkcs11_init"); | |
2065 | } | |
2066 | #endif | |
3375e053 PP |
2067 | rc = gnutls_global_init(); |
2068 | validate_check_rc(US"gnutls_global_init()"); | |
2069 | exim_gnutls_base_init_done = TRUE; | |
2070 | ||
2071 | if (!(tls_require_ciphers && *tls_require_ciphers)) | |
2072 | return_deinit(NULL); | |
2073 | ||
2074 | if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) | |
2075 | return_deinit(US"failed to expand tls_require_ciphers"); | |
2076 | ||
2077 | if (!(expciphers && *expciphers)) | |
2078 | return_deinit(NULL); | |
2079 | ||
2080 | DEBUG(D_tls) | |
2081 | debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); | |
2082 | ||
2083 | rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); | |
2084 | validate_check_rc(string_sprintf( | |
2085 | "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", | |
2086 | expciphers, errpos - CS expciphers, errpos)); | |
2087 | ||
2088 | #undef return_deinit | |
2089 | #undef validate_check_rc | |
2090 | gnutls_global_deinit(); | |
2091 | ||
2092 | return NULL; | |
2093 | } | |
2094 | ||
2095 | ||
2096 | ||
2097 | ||
36f12725 NM |
2098 | /************************************************* |
2099 | * Report the library versions. * | |
2100 | *************************************************/ | |
2101 | ||
2102 | /* See a description in tls-openssl.c for an explanation of why this exists. | |
2103 | ||
2104 | Arguments: a FILE* to print the results to | |
2105 | Returns: nothing | |
2106 | */ | |
2107 | ||
2108 | void | |
2109 | tls_version_report(FILE *f) | |
2110 | { | |
754a0503 PP |
2111 | fprintf(f, "Library version: GnuTLS: Compile: %s\n" |
2112 | " Runtime: %s\n", | |
2113 | LIBGNUTLS_VERSION, | |
2114 | gnutls_check_version(NULL)); | |
36f12725 NM |
2115 | } |
2116 | ||
2b4a568d JH |
2117 | /* vi: aw ai sw=2 |
2118 | */ | |
059ec3d9 | 2119 | /* End of tls-gnu.c */ |