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