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87054a31 | 1 | /* $Cambridge: exim/src/src/tls-gnu.c,v 1.15 2006/12/04 15:15:00 ph10 Exp $ */ |
059ec3d9 PH |
2 | |
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
d7d7b7b9 | 7 | /* Copyright (c) University of Cambridge 1995 - 2006 */ |
059ec3d9 PH |
8 | /* See the file NOTICE for conditions of use and distribution. */ |
9 | ||
10 | /* This module provides TLS (aka SSL) support for Exim using the GnuTLS | |
11 | library. It is #included into tls.c when that library is used. The code herein | |
12 | is based on a patch that was contributed by Nikos Mavroyanopoulos. | |
13 | ||
14 | No cryptographic code is included in Exim. All this module does is to call | |
15 | functions from the GnuTLS library. */ | |
16 | ||
17 | ||
18 | /* Heading stuff for GnuTLS */ | |
19 | ||
20 | #include <gnutls/gnutls.h> | |
21 | #include <gnutls/x509.h> | |
22 | ||
23 | ||
24 | #define UNKNOWN_NAME "unknown" | |
87054a31 | 25 | #define DH_BITS 1024 |
b5aea5e1 PH |
26 | #define PARAM_SIZE 2*1024 |
27 | ||
059ec3d9 PH |
28 | |
29 | /* Values for verify_requirment and initialized */ | |
30 | ||
31 | enum { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; | |
32 | enum { INITIALIZED_NOT, INITIALIZED_SERVER, INITIALIZED_CLIENT }; | |
33 | ||
34 | /* Local static variables for GNUTLS */ | |
35 | ||
36 | static BOOL initialized = INITIALIZED_NOT; | |
37 | static host_item *client_host; | |
38 | ||
059ec3d9 PH |
39 | static gnutls_dh_params dh_params = NULL; |
40 | ||
41 | static gnutls_certificate_server_credentials x509_cred = NULL; | |
42 | static gnutls_session tls_session = NULL; | |
43 | ||
44 | static char ssl_errstring[256]; | |
45 | ||
46 | static int ssl_session_timeout = 200; | |
47 | static int verify_requirement; | |
48 | ||
49 | /* Priorities for TLS algorithms to use. At present, only the cipher priority | |
50 | vector can be altered. */ | |
51 | ||
52 | static const int protocol_priority[16] = { GNUTLS_TLS1, GNUTLS_SSL3, 0 }; | |
53 | ||
54 | static const int kx_priority[16] = { | |
55 | GNUTLS_KX_RSA, | |
56 | GNUTLS_KX_DHE_DSS, | |
57 | GNUTLS_KX_DHE_RSA, | |
059ec3d9 PH |
58 | 0 }; |
59 | ||
60 | static int default_cipher_priority[16] = { | |
26dd5a95 | 61 | GNUTLS_CIPHER_AES_256_CBC, |
059ec3d9 PH |
62 | GNUTLS_CIPHER_AES_128_CBC, |
63 | GNUTLS_CIPHER_3DES_CBC, | |
26dd5a95 | 64 | GNUTLS_CIPHER_ARCFOUR_128, |
059ec3d9 PH |
65 | 0 }; |
66 | ||
67 | static int cipher_priority[16]; | |
68 | ||
69 | static const int mac_priority[16] = { | |
70 | GNUTLS_MAC_SHA, | |
71 | GNUTLS_MAC_MD5, | |
72 | 0 }; | |
73 | ||
74 | static const int comp_priority[16] = { GNUTLS_COMP_NULL, 0 }; | |
75 | static const int cert_type_priority[16] = { GNUTLS_CRT_X509, 0 }; | |
76 | ||
77 | /* Tables of cipher names and equivalent numbers */ | |
78 | ||
79 | typedef struct pri_item { | |
80 | uschar *name; | |
81 | int *values; | |
82 | } pri_item; | |
83 | ||
84 | static int arcfour_128_codes[] = { GNUTLS_CIPHER_ARCFOUR_128, 0 }; | |
85 | static int arcfour_40_codes[] = { GNUTLS_CIPHER_ARCFOUR_40, 0 }; | |
86 | static int arcfour_codes[] = { GNUTLS_CIPHER_ARCFOUR_128, | |
87 | GNUTLS_CIPHER_ARCFOUR_40, 0 }; | |
88 | static int aes_256_codes[] = { GNUTLS_CIPHER_AES_256_CBC, 0 }; | |
89 | static int aes_128_codes[] = { GNUTLS_CIPHER_AES_128_CBC, 0 }; | |
90 | static int aes_codes[] = { GNUTLS_CIPHER_AES_256_CBC, | |
91 | GNUTLS_CIPHER_AES_128_CBC, 0 }; | |
92 | static int des3_codes[] = { GNUTLS_CIPHER_3DES_CBC, 0 }; | |
93 | ||
94 | static pri_item cipher_index[] = { | |
95 | { US"ARCFOUR_128", arcfour_128_codes }, | |
96 | { US"ARCFOUR_40", arcfour_40_codes }, | |
97 | { US"ARCFOUR", arcfour_codes }, | |
98 | { US"AES_256", aes_256_codes }, | |
99 | { US"AES_128", aes_128_codes }, | |
100 | { US"AES", aes_codes }, | |
101 | { US"3DES", des3_codes } | |
102 | }; | |
103 | ||
104 | ||
105 | ||
106 | /************************************************* | |
107 | * Handle TLS error * | |
108 | *************************************************/ | |
109 | ||
110 | /* Called from lots of places when errors occur before actually starting to do | |
111 | the TLS handshake, that is, while the session is still in clear. Always returns | |
112 | DEFER for a server and FAIL for a client so that most calls can use "return | |
113 | tls_error(...)" to do this processing and then give an appropriate return. A | |
114 | single function is used for both server and client, because it is called from | |
115 | some shared functions. | |
116 | ||
117 | Argument: | |
118 | prefix text to include in the logged error | |
119 | host NULL if setting up a server; | |
120 | the connected host if setting up a client | |
121 | err a GnuTLS error number, or 0 if local error | |
122 | ||
123 | Returns: OK/DEFER/FAIL | |
124 | */ | |
125 | ||
126 | static int | |
127 | tls_error(uschar *prefix, host_item *host, int err) | |
128 | { | |
129 | uschar *errtext = US""; | |
130 | if (err != 0) errtext = string_sprintf(": %s", gnutls_strerror(err)); | |
131 | if (host == NULL) | |
132 | { | |
133 | log_write(0, LOG_MAIN, "TLS error on connection from %s (%s)%s", | |
134 | (sender_fullhost != NULL)? sender_fullhost : US "local process", | |
135 | prefix, errtext); | |
136 | return DEFER; | |
137 | } | |
138 | else | |
139 | { | |
140 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s", | |
141 | host->name, host->address, prefix, errtext); | |
142 | return FAIL; | |
143 | } | |
144 | } | |
145 | ||
146 | ||
147 | ||
148 | /************************************************* | |
149 | * Verify certificate * | |
150 | *************************************************/ | |
151 | ||
152 | /* Called after a successful handshake, when certificate verification is | |
153 | required or optional, for both server and client. | |
154 | ||
155 | Arguments: | |
156 | session GNUTLS session | |
157 | error where to put text giving a reason for failure | |
158 | ||
159 | Returns: TRUE/FALSE | |
160 | */ | |
161 | ||
162 | static BOOL | |
163 | verify_certificate(gnutls_session session, uschar **error) | |
164 | { | |
165 | int verify; | |
166 | uschar *dn_string = US""; | |
167 | const gnutls_datum *cert; | |
168 | unsigned int cert_size = 0; | |
169 | ||
170 | *error = NULL; | |
171 | ||
172 | /* Get the peer's certificate. If it sent one, extract it's DN, and then | |
173 | attempt to verify the certificate. If no certificate is supplied, verification | |
174 | is forced to fail. */ | |
175 | ||
176 | cert = gnutls_certificate_get_peers(session, &cert_size); | |
177 | if (cert != NULL) | |
178 | { | |
179 | uschar buff[1024]; | |
180 | gnutls_x509_crt gcert; | |
181 | ||
182 | gnutls_x509_crt_init(&gcert); | |
183 | dn_string = US"unknown"; | |
184 | ||
185 | if (gnutls_x509_crt_import(gcert, cert, GNUTLS_X509_FMT_DER) == 0) | |
186 | { | |
187 | size_t bufsize = sizeof(buff); | |
188 | if (gnutls_x509_crt_get_dn(gcert, CS buff, &bufsize) >= 0) | |
189 | dn_string = string_copy_malloc(buff); | |
190 | } | |
191 | ||
192 | verify = gnutls_certificate_verify_peers(session); | |
193 | } | |
194 | else | |
195 | { | |
196 | DEBUG(D_tls) debug_printf("no peer certificate supplied\n"); | |
197 | verify = GNUTLS_CERT_INVALID; | |
198 | *error = US"not supplied"; | |
199 | } | |
200 | ||
201 | /* Handle the result of verification. INVALID seems to be set as well | |
202 | as REVOKED, but leave the test for both. */ | |
203 | ||
204 | if ((verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) | |
205 | { | |
206 | tls_certificate_verified = FALSE; | |
207 | if (*error == NULL) *error = ((verify & GNUTLS_CERT_REVOKED) != 0)? | |
208 | US"revoked" : US"invalid"; | |
209 | if (verify_requirement == VERIFY_REQUIRED) | |
210 | { | |
211 | DEBUG(D_tls) debug_printf("TLS certificate verification failed (%s): " | |
212 | "peerdn=%s\n", *error, dn_string); | |
213 | gnutls_alert_send(session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
214 | return FALSE; /* reject */ | |
215 | } | |
216 | DEBUG(D_tls) debug_printf("TLS certificate verify failure (%s) overridden " | |
217 | "(host in tls_try_verify_hosts): peerdn=%s\n", *error, dn_string); | |
218 | } | |
219 | else | |
220 | { | |
221 | tls_certificate_verified = TRUE; | |
222 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", | |
223 | dn_string); | |
224 | } | |
225 | ||
226 | tls_peerdn = dn_string; | |
227 | return TRUE; /* accept */ | |
228 | } | |
229 | ||
230 | ||
231 | ||
059ec3d9 | 232 | /************************************************* |
575643cd | 233 | * Setup up DH parameters * |
059ec3d9 PH |
234 | *************************************************/ |
235 | ||
575643cd | 236 | /* Generating the D-H parameters may take a long time. They only need to |
059ec3d9 PH |
237 | be re-generated every so often, depending on security policy. What we do is to |
238 | keep these parameters in a file in the spool directory. If the file does not | |
239 | exist, we generate them. This means that it is easy to cause a regeneration. | |
240 | ||
241 | The new file is written as a temporary file and renamed, so that an incomplete | |
242 | file is never present. If two processes both compute some new parameters, you | |
243 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
244 | prevent this. | |
245 | ||
246 | Argument: | |
247 | host NULL for server, server for client (for error handling) | |
248 | ||
249 | Returns: OK/DEFER/FAIL | |
250 | */ | |
251 | ||
252 | static int | |
575643cd | 253 | init_dh(host_item *host) |
059ec3d9 | 254 | { |
b5aea5e1 | 255 | int fd; |
182ad5cf | 256 | int ret; |
b5aea5e1 | 257 | gnutls_datum m; |
059ec3d9 PH |
258 | uschar filename[200]; |
259 | ||
260 | /* Initialize the data structures for holding the parameters */ | |
261 | ||
059ec3d9 PH |
262 | ret = gnutls_dh_params_init(&dh_params); |
263 | if (ret < 0) return tls_error(US"init dh_params", host, ret); | |
264 | ||
265 | /* Set up the name of the cache file */ | |
266 | ||
267 | if (!string_format(filename, sizeof(filename), "%s/gnutls-params", | |
268 | spool_directory)) | |
269 | return tls_error(US"overlong filename", host, 0); | |
270 | ||
b5aea5e1 | 271 | /* Open the cache file for reading and if successful, read it and set up the |
575643cd | 272 | parameters. */ |
059ec3d9 PH |
273 | |
274 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 275 | if (fd >= 0) |
059ec3d9 | 276 | { |
b5aea5e1 PH |
277 | struct stat statbuf; |
278 | if (fstat(fd, &statbuf) < 0) | |
279 | { | |
280 | (void)close(fd); | |
281 | return tls_error(US"TLS cache stat failed", host, 0); | |
282 | } | |
059ec3d9 | 283 | |
b5aea5e1 PH |
284 | m.size = statbuf.st_size; |
285 | m.data = malloc(m.size); | |
286 | if (m.data == NULL) | |
287 | return tls_error(US"memory allocation failed", host, 0); | |
288 | if (read(fd, m.data, m.size) != m.size) | |
289 | return tls_error(US"TLS cache read failed", host, 0); | |
290 | (void)close(fd); | |
291 | ||
411ef850 PH |
292 | ret = gnutls_dh_params_import_pkcs3(dh_params, &m, GNUTLS_X509_FMT_PEM); |
293 | if (ret < 0) return tls_error(US"DH params import", host, ret); | |
575643cd | 294 | DEBUG(D_tls) debug_printf("read D-H parameters from file\n"); |
b5aea5e1 PH |
295 | |
296 | free(m.data); | |
297 | } | |
298 | ||
299 | /* If the file does not exist, fall through to compute new data and cache it. | |
300 | If there was any other opening error, it is serious. */ | |
301 | ||
182ad5cf PH |
302 | else if (errno == ENOENT) |
303 | { | |
304 | ret = -1; | |
305 | DEBUG(D_tls) | |
306 | debug_printf("parameter cache file %s does not exist\n", filename); | |
307 | } | |
308 | else | |
b5aea5e1 PH |
309 | return tls_error(string_open_failed(errno, "%s for reading", filename), |
310 | host, 0); | |
311 | ||
312 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
313 | is not useful. One particular case of this is when upgrading from an older | |
314 | release of Exim in which the data was stored in a different format. We don't | |
315 | try to be clever and support both formats; we just regenerate new data in this | |
316 | case. */ | |
317 | ||
318 | if (ret < 0) | |
319 | { | |
320 | uschar tempfilename[sizeof(filename) + 10]; | |
059ec3d9 | 321 | |
059ec3d9 PH |
322 | DEBUG(D_tls) debug_printf("generating %d bit Diffie-Hellman key...\n", |
323 | DH_BITS); | |
324 | ret = gnutls_dh_params_generate2(dh_params, DH_BITS); | |
325 | if (ret < 0) return tls_error(US"D-H key generation", host, ret); | |
326 | ||
327 | /* Write the parameters to a file in the spool directory so that we | |
328 | can use them from other Exim processes. */ | |
329 | ||
330 | sprintf(CS tempfilename, "%s-%d", filename, (int)getpid()); | |
331 | fd = Uopen(tempfilename, O_WRONLY|O_CREAT, 0400); | |
332 | if (fd < 0) | |
333 | return tls_error(string_open_failed(errno, "%s for writing", filename), | |
334 | host, 0); | |
335 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ | |
336 | ||
b5aea5e1 PH |
337 | /* export the parameters in a format that can be generated using GNUTLS' |
338 | * certtool or other programs. | |
339 | * | |
340 | * The commands for certtool are: | |
411ef850 | 341 | * $ certtool --generate-dh-params --bits 1024 > params |
b5aea5e1 PH |
342 | */ |
343 | ||
344 | m.size = PARAM_SIZE; | |
345 | m.data = malloc(m.size); | |
346 | if (m.data == NULL) | |
347 | return tls_error(US"memory allocation failed", host, 0); | |
348 | ||
b5aea5e1 PH |
349 | m.size = PARAM_SIZE; |
350 | ret = gnutls_dh_params_export_pkcs3(dh_params, GNUTLS_X509_FMT_PEM, m.data, | |
351 | &m.size); | |
059ec3d9 PH |
352 | if (ret < 0) return tls_error(US"DH params export", host, ret); |
353 | ||
b5aea5e1 PH |
354 | m.size = Ustrlen(m.data); |
355 | if (write(fd, m.data, m.size) != m.size || write(fd, "\n", 1) != 1) | |
059ec3d9 PH |
356 | return tls_error(US"TLS cache write failed", host, 0); |
357 | ||
b5aea5e1 | 358 | free(m.data); |
059ec3d9 PH |
359 | (void)close(fd); |
360 | ||
361 | if (rename(CS tempfilename, CS filename) < 0) | |
362 | return tls_error(string_sprintf("failed to rename %s as %s: %s", | |
363 | tempfilename, filename, strerror(errno)), host, 0); | |
364 | ||
411ef850 | 365 | DEBUG(D_tls) debug_printf("wrote D-H parameters to file %s\n", filename); |
059ec3d9 PH |
366 | } |
367 | ||
411ef850 | 368 | DEBUG(D_tls) debug_printf("initialized D-H parameters\n"); |
059ec3d9 PH |
369 | return OK; |
370 | } | |
371 | ||
372 | ||
373 | ||
374 | ||
375 | /************************************************* | |
376 | * Initialize for GnuTLS * | |
377 | *************************************************/ | |
378 | ||
379 | /* Called from both server and client code. In the case of a server, errors | |
380 | before actual TLS negotiation return DEFER. | |
381 | ||
382 | Arguments: | |
383 | host connected host, if client; NULL if server | |
384 | certificate certificate file | |
385 | privatekey private key file | |
386 | cas CA certs file | |
387 | crl CRL file | |
388 | ||
389 | Returns: OK/DEFER/FAIL | |
390 | */ | |
391 | ||
392 | static int | |
393 | tls_init(host_item *host, uschar *certificate, uschar *privatekey, uschar *cas, | |
394 | uschar *crl) | |
395 | { | |
396 | int rc; | |
397 | uschar *cert_expanded, *key_expanded, *cas_expanded, *crl_expanded; | |
398 | ||
399 | initialized = (host == NULL)? INITIALIZED_SERVER : INITIALIZED_CLIENT; | |
400 | ||
401 | rc = gnutls_global_init(); | |
402 | if (rc < 0) return tls_error(US"tls-init", host, rc); | |
403 | ||
575643cd PH |
404 | /* Create D-H parameters, or read them from the cache file. This function does |
405 | its own SMTP error messaging. */ | |
059ec3d9 | 406 | |
575643cd | 407 | rc = init_dh(host); |
059ec3d9 PH |
408 | if (rc != OK) return rc; |
409 | ||
410 | /* Create the credentials structure */ | |
411 | ||
412 | rc = gnutls_certificate_allocate_credentials(&x509_cred); | |
413 | if (rc < 0) return tls_error(US"certificate_allocate_credentials", host, rc); | |
414 | ||
415 | /* This stuff must be done for each session, because different certificates | |
416 | may be required for different sessions. */ | |
417 | ||
418 | if (!expand_check(certificate, US"tls_certificate", &cert_expanded)) | |
419 | return DEFER; | |
420 | ||
c91535f3 | 421 | key_expanded = NULL; |
059ec3d9 PH |
422 | if (privatekey != NULL) |
423 | { | |
424 | if (!expand_check(privatekey, US"tls_privatekey", &key_expanded)) | |
425 | return DEFER; | |
426 | } | |
c91535f3 PH |
427 | |
428 | /* If expansion was forced to fail, key_expanded will be NULL. If the result of | |
429 | the expansion is an empty string, ignore it also, and assume that the private | |
430 | key is in the same file as the certificate. */ | |
431 | ||
432 | if (key_expanded == NULL || *key_expanded == 0) | |
433 | key_expanded = cert_expanded; | |
059ec3d9 PH |
434 | |
435 | /* Set the certificate and private keys */ | |
436 | ||
437 | if (cert_expanded != NULL) | |
438 | { | |
439 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
440 | cert_expanded, key_expanded); | |
441 | rc = gnutls_certificate_set_x509_key_file(x509_cred, CS cert_expanded, | |
442 | CS key_expanded, GNUTLS_X509_FMT_PEM); | |
8e669ac1 | 443 | if (rc < 0) |
de365ded PH |
444 | { |
445 | uschar *msg = string_sprintf("cert/key setup: cert=%s key=%s", | |
8e669ac1 | 446 | cert_expanded, key_expanded); |
de365ded | 447 | return tls_error(msg, host, rc); |
8e669ac1 | 448 | } |
059ec3d9 PH |
449 | } |
450 | ||
451 | /* A certificate is mandatory in a server, but not in a client */ | |
452 | ||
453 | else | |
454 | { | |
455 | if (host == NULL) | |
456 | return tls_error(US"no TLS server certificate is specified", host, 0); | |
457 | DEBUG(D_tls) debug_printf("no TLS client certificate is specified\n"); | |
458 | } | |
459 | ||
460 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is | |
461 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
462 | error message is provided. However, if we just refrain from setting anything up | |
463 | in that case, certificate verification fails, which seems to be the correct | |
464 | behaviour. */ | |
465 | ||
466 | if (cas != NULL) | |
467 | { | |
468 | struct stat statbuf; | |
469 | ||
470 | if (!expand_check(cas, US"tls_verify_certificates", &cas_expanded)) | |
471 | return DEFER; | |
472 | ||
473 | if (stat(CS cas_expanded, &statbuf) < 0) | |
474 | { | |
475 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
476 | "(tls_verify_certificates): %s", cas_expanded, strerror(errno)); | |
477 | return DEFER; | |
478 | } | |
479 | ||
b1c749bb PH |
480 | DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", |
481 | cas_expanded, statbuf.st_size); | |
059ec3d9 PH |
482 | |
483 | /* If the cert file is empty, there's no point in loading the CRL file. */ | |
484 | ||
485 | if (statbuf.st_size > 0) | |
486 | { | |
487 | rc = gnutls_certificate_set_x509_trust_file(x509_cred, CS cas_expanded, | |
488 | GNUTLS_X509_FMT_PEM); | |
489 | if (rc < 0) return tls_error(US"setup_certs", host, rc); | |
490 | ||
491 | if (crl != NULL && *crl != 0) | |
492 | { | |
493 | if (!expand_check(crl, US"tls_crl", &crl_expanded)) | |
494 | return DEFER; | |
495 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", crl_expanded); | |
496 | rc = gnutls_certificate_set_x509_crl_file(x509_cred, CS crl_expanded, | |
497 | GNUTLS_X509_FMT_PEM); | |
498 | if (rc < 0) return tls_error(US"CRL setup", host, rc); | |
499 | } | |
500 | } | |
501 | } | |
502 | ||
503 | /* Associate the parameters with the x509 credentials structure. */ | |
504 | ||
505 | gnutls_certificate_set_dh_params(x509_cred, dh_params); | |
059ec3d9 PH |
506 | |
507 | DEBUG(D_tls) debug_printf("initialized certificate stuff\n"); | |
508 | return OK; | |
509 | } | |
510 | ||
511 | ||
512 | ||
513 | ||
514 | /************************************************* | |
515 | * Remove ciphers from priority list * | |
516 | *************************************************/ | |
517 | ||
518 | /* Cautiously written so that it will remove duplicates if present. | |
519 | ||
520 | Arguments: | |
521 | list a zero-terminated list | |
522 | remove_list a zero-terminated list to be removed | |
523 | ||
524 | Returns: nothing | |
525 | */ | |
526 | ||
527 | static void | |
528 | remove_ciphers(int *list, int *remove_list) | |
529 | { | |
530 | for (; *remove_list != 0; remove_list++) | |
531 | { | |
532 | int *p = list; | |
533 | while (*p != 0) | |
534 | { | |
535 | if (*p == *remove_list) | |
536 | { | |
537 | int *pp = p; | |
538 | do { pp[0] = pp[1]; pp++; } while (*pp != 0); | |
539 | } | |
540 | else p++; | |
541 | } | |
542 | } | |
543 | } | |
544 | ||
545 | ||
546 | ||
547 | /************************************************* | |
548 | * Add ciphers to priority list * | |
549 | *************************************************/ | |
550 | ||
551 | /* Cautiously written to check the list size | |
552 | ||
553 | Arguments: | |
554 | list a zero-terminated list | |
555 | list_max maximum offset in the list | |
556 | add_list a zero-terminated list to be added | |
557 | ||
558 | Returns: TRUE if OK; FALSE if list overflows | |
559 | */ | |
560 | ||
561 | static BOOL | |
562 | add_ciphers(int *list, int list_max, int *add_list) | |
563 | { | |
564 | int next = 0; | |
565 | while (list[next] != 0) next++; | |
566 | while (*add_list != 0) | |
567 | { | |
568 | if (next >= list_max) return FALSE; | |
569 | list[next++] = *add_list++; | |
570 | } | |
571 | list[next] = 0; | |
572 | return TRUE; | |
573 | } | |
574 | ||
575 | ||
576 | ||
577 | /************************************************* | |
578 | * Initialize a single GNUTLS session * | |
579 | *************************************************/ | |
580 | ||
581 | /* Set the algorithm, the db backend, whether to request certificates etc. | |
582 | ||
583 | TLS in Exim was first implemented using OpenSSL. This has a function to which | |
584 | you pass a list of cipher suites that are permitted/not permitted. GnuTLS works | |
585 | differently. It operates using priority lists for the different components of | |
586 | cipher suites. | |
587 | ||
588 | For compatibility of configuration, we scan a list of cipher suites and set | |
589 | priorities therefrom. However, at the moment, we pay attention only to the bulk | |
590 | cipher. | |
591 | ||
592 | Arguments: | |
593 | side one of GNUTLS_SERVER, GNUTLS_CLIENT | |
594 | expciphers expanded ciphers list | |
595 | ||
596 | Returns: a gnutls_session, or NULL if there is a problem | |
597 | */ | |
598 | ||
599 | static gnutls_session | |
600 | tls_session_init(int side, uschar *expciphers) | |
601 | { | |
602 | gnutls_session session; | |
603 | ||
604 | gnutls_init(&session, side); | |
605 | ||
606 | /* Handle the list of permitted ciphers */ | |
607 | ||
608 | memcpy(cipher_priority, default_cipher_priority, sizeof(cipher_priority)); | |
609 | ||
610 | if (expciphers != NULL) | |
611 | { | |
612 | int sep = 0; | |
613 | BOOL first = TRUE; | |
614 | uschar *cipher; | |
615 | ||
616 | /* The names OpenSSL uses are of the form DES-CBC3-SHA, using hyphen | |
617 | separators. GnuTLS uses underscore separators. So that I can use either form | |
618 | in my tests, and also for general convenience, we turn hyphens into | |
619 | underscores before scanning the list. */ | |
620 | ||
621 | uschar *s = expciphers; | |
622 | while (*s != 0) { if (*s == '-') *s = '_'; s++; } | |
623 | ||
624 | while ((cipher = string_nextinlist(&expciphers, &sep, big_buffer, | |
625 | big_buffer_size)) != NULL) | |
626 | { | |
627 | int i; | |
628 | BOOL exclude = cipher[0] == '!'; | |
629 | if (first && !exclude) cipher_priority[0] = 0; | |
630 | first = FALSE; | |
631 | ||
632 | for (i = 0; i < sizeof(cipher_index)/sizeof(pri_item); i++) | |
633 | { | |
634 | uschar *ss = strstric(cipher, cipher_index[i].name, FALSE); | |
635 | if (ss != NULL) | |
636 | { | |
637 | uschar *endss = ss + Ustrlen(cipher_index[i].name); | |
638 | if ((ss == cipher || !isalnum(ss[-1])) && !isalnum(*endss)) | |
639 | { | |
640 | if (exclude) | |
641 | remove_ciphers(cipher_priority, cipher_index[i].values); | |
642 | else | |
643 | { | |
644 | if (!add_ciphers(cipher_priority, | |
645 | sizeof(cipher_priority)/sizeof(pri_item), | |
646 | cipher_index[i].values)) | |
647 | { | |
648 | log_write(0, LOG_MAIN|LOG_PANIC, "GnuTLS init failed: cipher " | |
649 | "priority table overflow"); | |
650 | gnutls_deinit(session); | |
651 | return NULL; | |
652 | } | |
653 | } | |
654 | } | |
655 | } | |
656 | } | |
657 | } | |
658 | ||
659 | DEBUG(D_tls) | |
660 | { | |
661 | int *ptr = cipher_priority; | |
662 | debug_printf("adjusted cipher priorities:"); | |
663 | while (*ptr != 0) debug_printf(" %d", *ptr++); | |
664 | debug_printf("\n"); | |
665 | } | |
666 | } | |
667 | ||
668 | /* Define the various priorities */ | |
669 | ||
670 | gnutls_cipher_set_priority(session, cipher_priority); | |
671 | gnutls_compression_set_priority(session, comp_priority); | |
672 | gnutls_kx_set_priority(session, kx_priority); | |
673 | gnutls_protocol_set_priority(session, protocol_priority); | |
674 | gnutls_mac_set_priority(session, mac_priority); | |
675 | ||
676 | gnutls_cred_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred); | |
677 | ||
678 | gnutls_dh_set_prime_bits(session, DH_BITS); | |
679 | ||
680 | /* Request or demand a certificate of the peer, as configured. This will | |
681 | happen only in a server. */ | |
682 | ||
683 | if (verify_requirement != VERIFY_NONE) | |
684 | gnutls_certificate_server_set_request(session, | |
685 | (verify_requirement == VERIFY_OPTIONAL)? | |
686 | GNUTLS_CERT_REQUEST : GNUTLS_CERT_REQUIRE); | |
687 | ||
688 | gnutls_db_set_cache_expiration(session, ssl_session_timeout); | |
689 | ||
690 | DEBUG(D_tls) debug_printf("initialized GnuTLS session\n"); | |
691 | return session; | |
692 | } | |
693 | ||
694 | ||
695 | ||
696 | /************************************************* | |
697 | * Get name of cipher in use * | |
698 | *************************************************/ | |
699 | ||
700 | /* The answer is left in a static buffer, and tls_cipher is set to point | |
701 | to it. | |
702 | ||
703 | Argument: pointer to a GnuTLS session | |
704 | Returns: nothing | |
705 | */ | |
706 | ||
707 | static void | |
708 | construct_cipher_name(gnutls_session session) | |
709 | { | |
710 | static uschar cipherbuf[256]; | |
711 | uschar *ver; | |
712 | int bits, c, kx, mac; | |
713 | ||
714 | ver = string_copy( | |
715 | US gnutls_protocol_get_name(gnutls_protocol_get_version(session))); | |
716 | if (Ustrncmp(ver, "TLS ", 4) == 0) ver[3] = '-'; /* Don't want space */ | |
717 | ||
718 | c = gnutls_cipher_get(session); | |
719 | bits = gnutls_cipher_get_key_size(c); | |
720 | ||
721 | mac = gnutls_mac_get(session); | |
722 | kx = gnutls_kx_get(session); | |
723 | ||
724 | string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver, | |
725 | gnutls_cipher_suite_get_name(kx, c, mac), bits); | |
726 | tls_cipher = cipherbuf; | |
727 | ||
728 | DEBUG(D_tls) debug_printf("cipher: %s\n", cipherbuf); | |
729 | } | |
730 | ||
731 | ||
732 | ||
733 | /************************************************* | |
734 | * Start a TLS session in a server * | |
735 | *************************************************/ | |
736 | ||
737 | /* This is called when Exim is running as a server, after having received | |
738 | the STARTTLS command. It must respond to that command, and then negotiate | |
739 | a TLS session. | |
740 | ||
741 | Arguments: | |
742 | require_ciphers list of allowed ciphers | |
743 | ||
744 | Returns: OK on success | |
745 | DEFER for errors before the start of the negotiation | |
746 | FAIL for errors during the negotation; the server can't | |
747 | continue running. | |
748 | */ | |
749 | ||
750 | int | |
751 | tls_server_start(uschar *require_ciphers) | |
752 | { | |
753 | int rc; | |
754 | uschar *error; | |
755 | uschar *expciphers = NULL; | |
756 | ||
757 | /* Check for previous activation */ | |
758 | ||
759 | if (tls_active >= 0) | |
760 | { | |
761 | log_write(0, LOG_MAIN, "STARTTLS received in already encrypted " | |
762 | "connection from %s", | |
763 | (sender_fullhost != NULL)? sender_fullhost : US"local process"); | |
764 | smtp_printf("554 Already in TLS\r\n"); | |
765 | return FAIL; | |
766 | } | |
767 | ||
768 | /* Initialize the library. If it fails, it will already have logged the error | |
769 | and sent an SMTP response. */ | |
770 | ||
771 | DEBUG(D_tls) debug_printf("initializing GnuTLS as a server\n"); | |
772 | ||
773 | rc = tls_init(NULL, tls_certificate, tls_privatekey, tls_verify_certificates, | |
774 | tls_crl); | |
775 | if (rc != OK) return rc; | |
776 | ||
777 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
778 | return FAIL; | |
779 | ||
780 | /* If this is a host for which certificate verification is mandatory or | |
781 | optional, set up appropriately. */ | |
782 | ||
783 | tls_certificate_verified = FALSE; | |
784 | verify_requirement = VERIFY_NONE; | |
785 | ||
786 | if (verify_check_host(&tls_verify_hosts) == OK) | |
787 | verify_requirement = VERIFY_REQUIRED; | |
788 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
789 | verify_requirement = VERIFY_OPTIONAL; | |
790 | ||
791 | /* Prepare for new connection */ | |
792 | ||
793 | tls_session = tls_session_init(GNUTLS_SERVER, expciphers); | |
794 | if (tls_session == NULL) | |
795 | return tls_error(US"tls_session_init", NULL, GNUTLS_E_MEMORY_ERROR); | |
796 | ||
797 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
798 | on connection, where outputting anything now upsets the clients and tends to | |
799 | make them disconnect. We need to have an explicit fflush() here, to force out | |
800 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
801 | mode, the fflush() happens when smtp_getc() is called. */ | |
802 | ||
803 | if (!tls_on_connect) | |
804 | { | |
805 | smtp_printf("220 TLS go ahead\r\n"); | |
806 | fflush(smtp_out); | |
807 | } | |
808 | ||
809 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
810 | that the GnuTLS library doesn't. */ | |
811 | ||
812 | gnutls_transport_set_ptr(tls_session, (gnutls_transport_ptr)fileno(smtp_out)); | |
813 | ||
814 | sigalrm_seen = FALSE; | |
815 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
816 | rc = gnutls_handshake(tls_session); | |
817 | alarm(0); | |
818 | ||
819 | if (rc < 0) | |
820 | { | |
821 | if (sigalrm_seen) | |
822 | Ustrcpy(ssl_errstring, "timed out"); | |
823 | else | |
824 | Ustrcpy(ssl_errstring, gnutls_strerror(rc)); | |
825 | log_write(0, LOG_MAIN, | |
826 | "TLS error on connection from %s (gnutls_handshake): %s", | |
827 | (sender_fullhost != NULL)? sender_fullhost : US"local process", | |
828 | ssl_errstring); | |
829 | ||
830 | /* It seems that, except in the case of a timeout, we have to close the | |
831 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
832 | until the server times out. */ | |
833 | ||
834 | if (!sigalrm_seen) | |
835 | { | |
f1e894f3 PH |
836 | (void)fclose(smtp_out); |
837 | (void)fclose(smtp_in); | |
059ec3d9 PH |
838 | } |
839 | ||
840 | return FAIL; | |
841 | } | |
842 | ||
843 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
844 | ||
845 | if (verify_requirement != VERIFY_NONE && | |
846 | !verify_certificate(tls_session, &error)) | |
847 | { | |
848 | log_write(0, LOG_MAIN, | |
849 | "TLS error on connection from %s: certificate verification failed (%s)", | |
850 | (sender_fullhost != NULL)? sender_fullhost : US"local process", error); | |
851 | return FAIL; | |
852 | } | |
853 | ||
854 | construct_cipher_name(tls_session); | |
855 | ||
856 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
857 | and initialize appropriately. */ | |
858 | ||
859 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); | |
860 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
861 | ssl_xfer_eof = ssl_xfer_error = 0; | |
862 | ||
863 | receive_getc = tls_getc; | |
864 | receive_ungetc = tls_ungetc; | |
865 | receive_feof = tls_feof; | |
866 | receive_ferror = tls_ferror; | |
867 | ||
868 | tls_active = fileno(smtp_out); | |
869 | ||
870 | return OK; | |
871 | } | |
872 | ||
873 | ||
874 | ||
875 | ||
876 | /************************************************* | |
877 | * Start a TLS session in a client * | |
878 | *************************************************/ | |
879 | ||
880 | /* Called from the smtp transport after STARTTLS has been accepted. | |
881 | ||
882 | Arguments: | |
883 | fd the fd of the connection | |
884 | host connected host (for messages) | |
885 | addr | |
886 | dhparam DH parameter file | |
887 | certificate certificate file | |
888 | privatekey private key file | |
889 | verify_certs file for certificate verify | |
890 | verify_crl CRL for verify | |
891 | require_ciphers list of allowed ciphers | |
892 | timeout startup timeout | |
893 | ||
894 | Returns: OK/DEFER/FAIL (because using common functions), | |
895 | but for a client, DEFER and FAIL have the same meaning | |
896 | */ | |
897 | ||
898 | int | |
899 | tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, | |
900 | uschar *certificate, uschar *privatekey, uschar *verify_certs, | |
901 | uschar *verify_crl, uschar *require_ciphers, int timeout) | |
902 | { | |
903 | const gnutls_datum *server_certs; | |
904 | uschar *expciphers = NULL; | |
905 | uschar *error; | |
906 | unsigned int server_certs_size; | |
907 | int rc; | |
908 | ||
909 | DEBUG(D_tls) debug_printf("initializing GnuTLS as a client\n"); | |
910 | ||
911 | client_host = host; | |
912 | verify_requirement = (verify_certs == NULL)? VERIFY_NONE : VERIFY_REQUIRED; | |
913 | rc = tls_init(host, certificate, privatekey, verify_certs, verify_crl); | |
914 | if (rc != OK) return rc; | |
915 | ||
916 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
917 | return FAIL; | |
918 | ||
919 | tls_session = tls_session_init(GNUTLS_CLIENT, expciphers); | |
920 | if (tls_session == NULL) | |
921 | return tls_error(US "tls_session_init", host, GNUTLS_E_MEMORY_ERROR); | |
922 | ||
923 | gnutls_transport_set_ptr(tls_session, (gnutls_transport_ptr)fd); | |
924 | ||
925 | /* There doesn't seem to be a built-in timeout on connection. */ | |
926 | ||
927 | sigalrm_seen = FALSE; | |
928 | alarm(timeout); | |
929 | rc = gnutls_handshake(tls_session); | |
930 | alarm(0); | |
931 | ||
932 | if (rc < 0) | |
933 | { | |
934 | if (sigalrm_seen) | |
935 | { | |
936 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s]: " | |
937 | "gnutls_handshake timed out", host->name, host->address); | |
938 | return FAIL; | |
939 | } | |
940 | else return tls_error(US "gnutls_handshake", host, rc); | |
941 | } | |
942 | ||
943 | server_certs = gnutls_certificate_get_peers(tls_session, &server_certs_size); | |
944 | ||
945 | if (server_certs != NULL) | |
946 | { | |
947 | uschar buff[1024]; | |
948 | gnutls_x509_crt gcert; | |
949 | ||
950 | gnutls_x509_crt_init(&gcert); | |
951 | tls_peerdn = US"unknown"; | |
952 | ||
953 | if (gnutls_x509_crt_import(gcert, server_certs, GNUTLS_X509_FMT_DER) == 0) | |
954 | { | |
955 | size_t bufsize = sizeof(buff); | |
956 | if (gnutls_x509_crt_get_dn(gcert, CS buff, &bufsize) >= 0) | |
957 | tls_peerdn = string_copy_malloc(buff); | |
958 | } | |
959 | } | |
960 | ||
961 | /* Should we also verify the hostname here? */ | |
962 | ||
963 | if (verify_requirement != VERIFY_NONE && | |
964 | !verify_certificate(tls_session, &error)) | |
965 | { | |
966 | log_write(0, LOG_MAIN, | |
967 | "TLS error on connection to %s [%s]: certificate verification failed (%s)", | |
968 | host->name, host->address, error); | |
969 | return FAIL; | |
970 | } | |
971 | ||
972 | construct_cipher_name(tls_session); /* Sets tls_cipher */ | |
973 | tls_active = fd; | |
974 | return OK; | |
975 | } | |
976 | ||
977 | ||
978 | ||
979 | /************************************************* | |
980 | * Deal with logging errors during I/O * | |
981 | *************************************************/ | |
982 | ||
983 | /* We have to get the identity of the peer from saved data. | |
984 | ||
985 | Argument: | |
986 | ec the GnuTLS error code, or 0 if it's a local error | |
987 | when text identifying read or write | |
988 | text local error text when ec is 0 | |
989 | ||
990 | Returns: nothing | |
991 | */ | |
992 | ||
993 | static void | |
994 | record_io_error(int ec, uschar *when, uschar *text) | |
995 | { | |
996 | uschar *additional = US""; | |
997 | ||
998 | if (ec == GNUTLS_E_FATAL_ALERT_RECEIVED) | |
999 | additional = string_sprintf(": %s", | |
1000 | gnutls_alert_get_name(gnutls_alert_get(tls_session))); | |
1001 | ||
1002 | if (initialized == INITIALIZED_SERVER) | |
1003 | log_write(0, LOG_MAIN, "TLS %s error on connection from %s: %s%s", when, | |
1004 | (sender_fullhost != NULL)? sender_fullhost : US "local process", | |
1005 | (ec == 0)? text : US gnutls_strerror(ec), additional); | |
1006 | ||
1007 | else | |
1008 | log_write(0, LOG_MAIN, "TLS %s error on connection to %s [%s]: %s%s", when, | |
1009 | client_host->name, client_host->address, | |
1010 | (ec == 0)? text : US gnutls_strerror(ec), additional); | |
1011 | } | |
1012 | ||
1013 | ||
1014 | ||
1015 | /************************************************* | |
1016 | * TLS version of getc * | |
1017 | *************************************************/ | |
1018 | ||
1019 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1020 | it refills the buffer via the GnuTLS reading function. | |
1021 | ||
1022 | Arguments: none | |
1023 | Returns: the next character or EOF | |
1024 | */ | |
1025 | ||
1026 | int | |
1027 | tls_getc(void) | |
1028 | { | |
1029 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1030 | { | |
1031 | int inbytes; | |
1032 | ||
1033 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%lx, %lx, %u)\n", | |
1034 | (long) tls_session, (long) ssl_xfer_buffer, ssl_xfer_buffer_size); | |
1035 | ||
1036 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1037 | inbytes = gnutls_record_recv(tls_session, CS ssl_xfer_buffer, | |
1038 | ssl_xfer_buffer_size); | |
1039 | alarm(0); | |
1040 | ||
1041 | /* A zero-byte return appears to mean that the TLS session has been | |
1042 | closed down, not that the socket itself has been closed down. Revert to | |
1043 | non-TLS handling. */ | |
1044 | ||
1045 | if (inbytes == 0) | |
1046 | { | |
1047 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1048 | ||
1049 | receive_getc = smtp_getc; | |
1050 | receive_ungetc = smtp_ungetc; | |
1051 | receive_feof = smtp_feof; | |
1052 | receive_ferror = smtp_ferror; | |
1053 | ||
1054 | gnutls_deinit(tls_session); | |
1055 | tls_session = NULL; | |
1056 | tls_active = -1; | |
1057 | tls_cipher = NULL; | |
1058 | tls_peerdn = NULL; | |
1059 | ||
1060 | return smtp_getc(); | |
1061 | } | |
1062 | ||
1063 | /* Handle genuine errors */ | |
1064 | ||
1065 | else if (inbytes < 0) | |
1066 | { | |
1067 | record_io_error(inbytes, US"recv", NULL); | |
1068 | ssl_xfer_error = 1; | |
1069 | return EOF; | |
1070 | } | |
1071 | ||
1072 | ssl_xfer_buffer_hwm = inbytes; | |
1073 | ssl_xfer_buffer_lwm = 0; | |
1074 | } | |
1075 | ||
1076 | ||
1077 | /* Something in the buffer; return next uschar */ | |
1078 | ||
1079 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1080 | } | |
1081 | ||
1082 | ||
1083 | ||
1084 | /************************************************* | |
1085 | * Read bytes from TLS channel * | |
1086 | *************************************************/ | |
1087 | ||
1088 | /* | |
1089 | Arguments: | |
1090 | buff buffer of data | |
1091 | len size of buffer | |
1092 | ||
1093 | Returns: the number of bytes read | |
1094 | -1 after a failed read | |
1095 | */ | |
1096 | ||
1097 | int | |
1098 | tls_read(uschar *buff, size_t len) | |
1099 | { | |
1100 | int inbytes; | |
1101 | ||
1102 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%lx, %lx, %u)\n", | |
1103 | (long) tls_session, (long) buff, len); | |
1104 | ||
1105 | inbytes = gnutls_record_recv(tls_session, CS buff, len); | |
1106 | if (inbytes > 0) return inbytes; | |
1107 | if (inbytes == 0) | |
1108 | { | |
1109 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1110 | } | |
1111 | else record_io_error(inbytes, US"recv", NULL); | |
1112 | ||
1113 | return -1; | |
1114 | } | |
1115 | ||
1116 | ||
1117 | ||
1118 | /************************************************* | |
1119 | * Write bytes down TLS channel * | |
1120 | *************************************************/ | |
1121 | ||
1122 | /* | |
1123 | Arguments: | |
1124 | buff buffer of data | |
1125 | len number of bytes | |
1126 | ||
1127 | Returns: the number of bytes after a successful write, | |
1128 | -1 after a failed write | |
1129 | */ | |
1130 | ||
1131 | int | |
1132 | tls_write(const uschar *buff, size_t len) | |
1133 | { | |
1134 | int outbytes; | |
1135 | int left = len; | |
1136 | ||
1137 | DEBUG(D_tls) debug_printf("tls_do_write(%lx, %d)\n", (long) buff, left); | |
1138 | while (left > 0) | |
1139 | { | |
1140 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %lx, %d)\n", (long)buff, | |
1141 | left); | |
1142 | outbytes = gnutls_record_send(tls_session, CS buff, left); | |
1143 | ||
1144 | DEBUG(D_tls) debug_printf("outbytes=%d\n", outbytes); | |
1145 | if (outbytes < 0) | |
1146 | { | |
1147 | record_io_error(outbytes, US"send", NULL); | |
1148 | return -1; | |
1149 | } | |
1150 | if (outbytes == 0) | |
1151 | { | |
1152 | record_io_error(0, US"send", US"TLS channel closed on write"); | |
1153 | return -1; | |
1154 | } | |
1155 | ||
1156 | left -= outbytes; | |
1157 | buff += outbytes; | |
1158 | } | |
1159 | ||
1160 | return len; | |
1161 | } | |
1162 | ||
1163 | ||
1164 | ||
1165 | /************************************************* | |
1166 | * Close down a TLS session * | |
1167 | *************************************************/ | |
1168 | ||
1169 | /* This is also called from within a delivery subprocess forked from the | |
1170 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1171 | would tamper with the TLS session in the parent process). | |
1172 | ||
1173 | Arguments: TRUE if gnutls_bye is to be called | |
1174 | Returns: nothing | |
1175 | */ | |
1176 | ||
1177 | void | |
1178 | tls_close(BOOL shutdown) | |
1179 | { | |
1180 | if (tls_active < 0) return; /* TLS was not active */ | |
1181 | ||
1182 | if (shutdown) | |
1183 | { | |
1184 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1185 | gnutls_bye(tls_session, GNUTLS_SHUT_WR); | |
1186 | } | |
1187 | ||
1188 | gnutls_deinit(tls_session); | |
1189 | tls_session = NULL; | |
1190 | gnutls_global_deinit(); | |
1191 | ||
1192 | tls_active = -1; | |
1193 | } | |
1194 | ||
1195 | /* End of tls-gnu.c */ |