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b5aea5e1 | 1 | /* $Cambridge: exim/src/src/tls-gnu.c,v 1.6 2005/03/08 11:38:21 ph10 Exp $ */ |
059ec3d9 PH |
2 | |
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
c988f1f4 | 7 | /* Copyright (c) University of Cambridge 1995 - 2005 */ |
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" | |
25 | #define DH_BITS 768 | |
26 | #define RSA_BITS 512 | |
b5aea5e1 PH |
27 | #define PARAM_SIZE 2*1024 |
28 | ||
059ec3d9 PH |
29 | |
30 | /* Values for verify_requirment and initialized */ | |
31 | ||
32 | enum { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; | |
33 | enum { INITIALIZED_NOT, INITIALIZED_SERVER, INITIALIZED_CLIENT }; | |
34 | ||
35 | /* Local static variables for GNUTLS */ | |
36 | ||
37 | static BOOL initialized = INITIALIZED_NOT; | |
38 | static host_item *client_host; | |
39 | ||
40 | static gnutls_rsa_params rsa_params = NULL; | |
41 | static gnutls_dh_params dh_params = NULL; | |
42 | ||
43 | static gnutls_certificate_server_credentials x509_cred = NULL; | |
44 | static gnutls_session tls_session = NULL; | |
45 | ||
46 | static char ssl_errstring[256]; | |
47 | ||
48 | static int ssl_session_timeout = 200; | |
49 | static int verify_requirement; | |
50 | ||
51 | /* Priorities for TLS algorithms to use. At present, only the cipher priority | |
52 | vector can be altered. */ | |
53 | ||
54 | static const int protocol_priority[16] = { GNUTLS_TLS1, GNUTLS_SSL3, 0 }; | |
55 | ||
56 | static const int kx_priority[16] = { | |
57 | GNUTLS_KX_RSA, | |
58 | GNUTLS_KX_DHE_DSS, | |
59 | GNUTLS_KX_DHE_RSA, | |
60 | GNUTLS_KX_RSA_EXPORT, | |
61 | 0 }; | |
62 | ||
63 | static int default_cipher_priority[16] = { | |
26dd5a95 | 64 | GNUTLS_CIPHER_AES_256_CBC, |
059ec3d9 PH |
65 | GNUTLS_CIPHER_AES_128_CBC, |
66 | GNUTLS_CIPHER_3DES_CBC, | |
26dd5a95 | 67 | GNUTLS_CIPHER_ARCFOUR_128, |
059ec3d9 PH |
68 | 0 }; |
69 | ||
70 | static int cipher_priority[16]; | |
71 | ||
72 | static const int mac_priority[16] = { | |
73 | GNUTLS_MAC_SHA, | |
74 | GNUTLS_MAC_MD5, | |
75 | 0 }; | |
76 | ||
77 | static const int comp_priority[16] = { GNUTLS_COMP_NULL, 0 }; | |
78 | static const int cert_type_priority[16] = { GNUTLS_CRT_X509, 0 }; | |
79 | ||
80 | /* Tables of cipher names and equivalent numbers */ | |
81 | ||
82 | typedef struct pri_item { | |
83 | uschar *name; | |
84 | int *values; | |
85 | } pri_item; | |
86 | ||
87 | static int arcfour_128_codes[] = { GNUTLS_CIPHER_ARCFOUR_128, 0 }; | |
88 | static int arcfour_40_codes[] = { GNUTLS_CIPHER_ARCFOUR_40, 0 }; | |
89 | static int arcfour_codes[] = { GNUTLS_CIPHER_ARCFOUR_128, | |
90 | GNUTLS_CIPHER_ARCFOUR_40, 0 }; | |
91 | static int aes_256_codes[] = { GNUTLS_CIPHER_AES_256_CBC, 0 }; | |
92 | static int aes_128_codes[] = { GNUTLS_CIPHER_AES_128_CBC, 0 }; | |
93 | static int aes_codes[] = { GNUTLS_CIPHER_AES_256_CBC, | |
94 | GNUTLS_CIPHER_AES_128_CBC, 0 }; | |
95 | static int des3_codes[] = { GNUTLS_CIPHER_3DES_CBC, 0 }; | |
96 | ||
97 | static pri_item cipher_index[] = { | |
98 | { US"ARCFOUR_128", arcfour_128_codes }, | |
99 | { US"ARCFOUR_40", arcfour_40_codes }, | |
100 | { US"ARCFOUR", arcfour_codes }, | |
101 | { US"AES_256", aes_256_codes }, | |
102 | { US"AES_128", aes_128_codes }, | |
103 | { US"AES", aes_codes }, | |
104 | { US"3DES", des3_codes } | |
105 | }; | |
106 | ||
107 | ||
108 | ||
109 | /************************************************* | |
110 | * Handle TLS error * | |
111 | *************************************************/ | |
112 | ||
113 | /* Called from lots of places when errors occur before actually starting to do | |
114 | the TLS handshake, that is, while the session is still in clear. Always returns | |
115 | DEFER for a server and FAIL for a client so that most calls can use "return | |
116 | tls_error(...)" to do this processing and then give an appropriate return. A | |
117 | single function is used for both server and client, because it is called from | |
118 | some shared functions. | |
119 | ||
120 | Argument: | |
121 | prefix text to include in the logged error | |
122 | host NULL if setting up a server; | |
123 | the connected host if setting up a client | |
124 | err a GnuTLS error number, or 0 if local error | |
125 | ||
126 | Returns: OK/DEFER/FAIL | |
127 | */ | |
128 | ||
129 | static int | |
130 | tls_error(uschar *prefix, host_item *host, int err) | |
131 | { | |
132 | uschar *errtext = US""; | |
133 | if (err != 0) errtext = string_sprintf(": %s", gnutls_strerror(err)); | |
134 | if (host == NULL) | |
135 | { | |
136 | log_write(0, LOG_MAIN, "TLS error on connection from %s (%s)%s", | |
137 | (sender_fullhost != NULL)? sender_fullhost : US "local process", | |
138 | prefix, errtext); | |
139 | return DEFER; | |
140 | } | |
141 | else | |
142 | { | |
143 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s", | |
144 | host->name, host->address, prefix, errtext); | |
145 | return FAIL; | |
146 | } | |
147 | } | |
148 | ||
149 | ||
150 | ||
151 | /************************************************* | |
152 | * Verify certificate * | |
153 | *************************************************/ | |
154 | ||
155 | /* Called after a successful handshake, when certificate verification is | |
156 | required or optional, for both server and client. | |
157 | ||
158 | Arguments: | |
159 | session GNUTLS session | |
160 | error where to put text giving a reason for failure | |
161 | ||
162 | Returns: TRUE/FALSE | |
163 | */ | |
164 | ||
165 | static BOOL | |
166 | verify_certificate(gnutls_session session, uschar **error) | |
167 | { | |
168 | int verify; | |
169 | uschar *dn_string = US""; | |
170 | const gnutls_datum *cert; | |
171 | unsigned int cert_size = 0; | |
172 | ||
173 | *error = NULL; | |
174 | ||
175 | /* Get the peer's certificate. If it sent one, extract it's DN, and then | |
176 | attempt to verify the certificate. If no certificate is supplied, verification | |
177 | is forced to fail. */ | |
178 | ||
179 | cert = gnutls_certificate_get_peers(session, &cert_size); | |
180 | if (cert != NULL) | |
181 | { | |
182 | uschar buff[1024]; | |
183 | gnutls_x509_crt gcert; | |
184 | ||
185 | gnutls_x509_crt_init(&gcert); | |
186 | dn_string = US"unknown"; | |
187 | ||
188 | if (gnutls_x509_crt_import(gcert, cert, GNUTLS_X509_FMT_DER) == 0) | |
189 | { | |
190 | size_t bufsize = sizeof(buff); | |
191 | if (gnutls_x509_crt_get_dn(gcert, CS buff, &bufsize) >= 0) | |
192 | dn_string = string_copy_malloc(buff); | |
193 | } | |
194 | ||
195 | verify = gnutls_certificate_verify_peers(session); | |
196 | } | |
197 | else | |
198 | { | |
199 | DEBUG(D_tls) debug_printf("no peer certificate supplied\n"); | |
200 | verify = GNUTLS_CERT_INVALID; | |
201 | *error = US"not supplied"; | |
202 | } | |
203 | ||
204 | /* Handle the result of verification. INVALID seems to be set as well | |
205 | as REVOKED, but leave the test for both. */ | |
206 | ||
207 | if ((verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) | |
208 | { | |
209 | tls_certificate_verified = FALSE; | |
210 | if (*error == NULL) *error = ((verify & GNUTLS_CERT_REVOKED) != 0)? | |
211 | US"revoked" : US"invalid"; | |
212 | if (verify_requirement == VERIFY_REQUIRED) | |
213 | { | |
214 | DEBUG(D_tls) debug_printf("TLS certificate verification failed (%s): " | |
215 | "peerdn=%s\n", *error, dn_string); | |
216 | gnutls_alert_send(session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); | |
217 | return FALSE; /* reject */ | |
218 | } | |
219 | DEBUG(D_tls) debug_printf("TLS certificate verify failure (%s) overridden " | |
220 | "(host in tls_try_verify_hosts): peerdn=%s\n", *error, dn_string); | |
221 | } | |
222 | else | |
223 | { | |
224 | tls_certificate_verified = TRUE; | |
225 | DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", | |
226 | dn_string); | |
227 | } | |
228 | ||
229 | tls_peerdn = dn_string; | |
230 | return TRUE; /* accept */ | |
231 | } | |
232 | ||
233 | ||
234 | ||
059ec3d9 PH |
235 | /************************************************* |
236 | * Setup up RSA and DH parameters * | |
237 | *************************************************/ | |
238 | ||
239 | /* Generating the RSA and D-H parameters takes a long time. They only need to | |
240 | be re-generated every so often, depending on security policy. What we do is to | |
241 | keep these parameters in a file in the spool directory. If the file does not | |
242 | exist, we generate them. This means that it is easy to cause a regeneration. | |
243 | ||
244 | The new file is written as a temporary file and renamed, so that an incomplete | |
245 | file is never present. If two processes both compute some new parameters, you | |
246 | waste a bit of effort, but it doesn't seem worth messing around with locking to | |
247 | prevent this. | |
248 | ||
249 | Argument: | |
250 | host NULL for server, server for client (for error handling) | |
251 | ||
252 | Returns: OK/DEFER/FAIL | |
253 | */ | |
254 | ||
255 | static int | |
256 | init_rsa_dh(host_item *host) | |
257 | { | |
b5aea5e1 PH |
258 | int fd; |
259 | int ret = -1; | |
260 | gnutls_datum m; | |
059ec3d9 PH |
261 | uschar filename[200]; |
262 | ||
263 | /* Initialize the data structures for holding the parameters */ | |
264 | ||
265 | ret = gnutls_rsa_params_init(&rsa_params); | |
266 | if (ret < 0) return tls_error(US"init rsa_params", host, ret); | |
267 | ||
268 | ret = gnutls_dh_params_init(&dh_params); | |
269 | if (ret < 0) return tls_error(US"init dh_params", host, ret); | |
270 | ||
271 | /* Set up the name of the cache file */ | |
272 | ||
273 | if (!string_format(filename, sizeof(filename), "%s/gnutls-params", | |
274 | spool_directory)) | |
275 | return tls_error(US"overlong filename", host, 0); | |
276 | ||
b5aea5e1 PH |
277 | /* Open the cache file for reading and if successful, read it and set up the |
278 | parameters. If we can't set up the RSA parameters, assume that we are dealing | |
279 | with an old-style cache file that is in another format, and fall through to | |
280 | compute new values. However, if we correctly get RSA parameters, a failure to | |
281 | set up D-H parameters is treated as an error. */ | |
059ec3d9 PH |
282 | |
283 | fd = Uopen(filename, O_RDONLY, 0); | |
b5aea5e1 | 284 | if (fd >= 0) |
059ec3d9 | 285 | { |
b5aea5e1 PH |
286 | struct stat statbuf; |
287 | if (fstat(fd, &statbuf) < 0) | |
288 | { | |
289 | (void)close(fd); | |
290 | return tls_error(US"TLS cache stat failed", host, 0); | |
291 | } | |
059ec3d9 | 292 | |
b5aea5e1 PH |
293 | m.size = statbuf.st_size; |
294 | m.data = malloc(m.size); | |
295 | if (m.data == NULL) | |
296 | return tls_error(US"memory allocation failed", host, 0); | |
297 | if (read(fd, m.data, m.size) != m.size) | |
298 | return tls_error(US"TLS cache read failed", host, 0); | |
299 | (void)close(fd); | |
300 | ||
301 | ret = gnutls_rsa_params_import_pkcs1(rsa_params, &m, GNUTLS_X509_FMT_PEM); | |
302 | if (ret < 0) | |
303 | { | |
304 | DEBUG(D_tls) | |
305 | debug_printf("RSA params import failed: assume old-style cache file\n"); | |
306 | } | |
307 | else | |
308 | { | |
309 | ret = gnutls_dh_params_import_pkcs3(dh_params, &m, GNUTLS_X509_FMT_PEM); | |
310 | if (ret < 0) | |
311 | return tls_error(US"DH params import", host, ret); | |
312 | DEBUG(D_tls) debug_printf("read RSA and D-H parameters from file\n"); | |
313 | } | |
314 | ||
315 | free(m.data); | |
316 | } | |
317 | ||
318 | /* If the file does not exist, fall through to compute new data and cache it. | |
319 | If there was any other opening error, it is serious. */ | |
320 | ||
321 | else if (errno != ENOENT) | |
322 | return tls_error(string_open_failed(errno, "%s for reading", filename), | |
323 | host, 0); | |
324 | ||
325 | /* If ret < 0, either the cache file does not exist, or the data it contains | |
326 | is not useful. One particular case of this is when upgrading from an older | |
327 | release of Exim in which the data was stored in a different format. We don't | |
328 | try to be clever and support both formats; we just regenerate new data in this | |
329 | case. */ | |
330 | ||
331 | if (ret < 0) | |
332 | { | |
333 | uschar tempfilename[sizeof(filename) + 10]; | |
059ec3d9 PH |
334 | |
335 | DEBUG(D_tls) debug_printf("generating %d bit RSA key...\n", RSA_BITS); | |
336 | ret = gnutls_rsa_params_generate2(rsa_params, RSA_BITS); | |
337 | if (ret < 0) return tls_error(US"RSA key generation", host, ret); | |
338 | ||
339 | DEBUG(D_tls) debug_printf("generating %d bit Diffie-Hellman key...\n", | |
340 | DH_BITS); | |
341 | ret = gnutls_dh_params_generate2(dh_params, DH_BITS); | |
342 | if (ret < 0) return tls_error(US"D-H key generation", host, ret); | |
343 | ||
344 | /* Write the parameters to a file in the spool directory so that we | |
345 | can use them from other Exim processes. */ | |
346 | ||
347 | sprintf(CS tempfilename, "%s-%d", filename, (int)getpid()); | |
348 | fd = Uopen(tempfilename, O_WRONLY|O_CREAT, 0400); | |
349 | if (fd < 0) | |
350 | return tls_error(string_open_failed(errno, "%s for writing", filename), | |
351 | host, 0); | |
352 | (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ | |
353 | ||
b5aea5e1 PH |
354 | /* export the parameters in a format that can be generated using GNUTLS' |
355 | * certtool or other programs. | |
356 | * | |
357 | * The commands for certtool are: | |
358 | * $ certtool --generate-privkey --bits 512 >params | |
359 | * $ echo "" >>params | |
360 | * $ certtool --generate-dh-params --bits 1024 >> params | |
361 | */ | |
362 | ||
363 | m.size = PARAM_SIZE; | |
364 | m.data = malloc(m.size); | |
365 | if (m.data == NULL) | |
366 | return tls_error(US"memory allocation failed", host, 0); | |
367 | ||
368 | ret = gnutls_rsa_params_export_pkcs1(rsa_params, GNUTLS_X509_FMT_PEM, | |
369 | m.data, &m.size); | |
059ec3d9 PH |
370 | if (ret < 0) return tls_error(US"RSA params export", host, ret); |
371 | ||
b5aea5e1 PH |
372 | /* Do not write the null termination byte. */ |
373 | ||
374 | m.size = Ustrlen(m.data); | |
375 | if (write(fd, m.data, m.size) != m.size || write(fd, "\n", 1) != 1) | |
376 | return tls_error(US"TLS cache write failed", host, 0); | |
377 | ||
378 | m.size = PARAM_SIZE; | |
379 | ret = gnutls_dh_params_export_pkcs3(dh_params, GNUTLS_X509_FMT_PEM, m.data, | |
380 | &m.size); | |
059ec3d9 PH |
381 | if (ret < 0) return tls_error(US"DH params export", host, ret); |
382 | ||
b5aea5e1 PH |
383 | m.size = Ustrlen(m.data); |
384 | if (write(fd, m.data, m.size) != m.size || write(fd, "\n", 1) != 1) | |
059ec3d9 PH |
385 | return tls_error(US"TLS cache write failed", host, 0); |
386 | ||
b5aea5e1 | 387 | free(m.data); |
059ec3d9 PH |
388 | (void)close(fd); |
389 | ||
390 | if (rename(CS tempfilename, CS filename) < 0) | |
391 | return tls_error(string_sprintf("failed to rename %s as %s: %s", | |
392 | tempfilename, filename, strerror(errno)), host, 0); | |
393 | ||
394 | DEBUG(D_tls) debug_printf("wrote RSA and D-H parameters to file\n"); | |
395 | } | |
396 | ||
059ec3d9 PH |
397 | DEBUG(D_tls) debug_printf("initialized RSA and D-H parameters\n"); |
398 | return OK; | |
399 | } | |
400 | ||
401 | ||
402 | ||
403 | ||
404 | /************************************************* | |
405 | * Initialize for GnuTLS * | |
406 | *************************************************/ | |
407 | ||
408 | /* Called from both server and client code. In the case of a server, errors | |
409 | before actual TLS negotiation return DEFER. | |
410 | ||
411 | Arguments: | |
412 | host connected host, if client; NULL if server | |
413 | certificate certificate file | |
414 | privatekey private key file | |
415 | cas CA certs file | |
416 | crl CRL file | |
417 | ||
418 | Returns: OK/DEFER/FAIL | |
419 | */ | |
420 | ||
421 | static int | |
422 | tls_init(host_item *host, uschar *certificate, uschar *privatekey, uschar *cas, | |
423 | uschar *crl) | |
424 | { | |
425 | int rc; | |
426 | uschar *cert_expanded, *key_expanded, *cas_expanded, *crl_expanded; | |
427 | ||
428 | initialized = (host == NULL)? INITIALIZED_SERVER : INITIALIZED_CLIENT; | |
429 | ||
430 | rc = gnutls_global_init(); | |
431 | if (rc < 0) return tls_error(US"tls-init", host, rc); | |
432 | ||
433 | /* Create RSA and D-H parameters, or read them from the cache file. This | |
434 | function does its own SMTP error messaging. */ | |
435 | ||
436 | rc = init_rsa_dh(host); | |
437 | if (rc != OK) return rc; | |
438 | ||
439 | /* Create the credentials structure */ | |
440 | ||
441 | rc = gnutls_certificate_allocate_credentials(&x509_cred); | |
442 | if (rc < 0) return tls_error(US"certificate_allocate_credentials", host, rc); | |
443 | ||
444 | /* This stuff must be done for each session, because different certificates | |
445 | may be required for different sessions. */ | |
446 | ||
447 | if (!expand_check(certificate, US"tls_certificate", &cert_expanded)) | |
448 | return DEFER; | |
449 | ||
450 | if (privatekey != NULL) | |
451 | { | |
452 | if (!expand_check(privatekey, US"tls_privatekey", &key_expanded)) | |
453 | return DEFER; | |
454 | } | |
455 | else key_expanded = cert_expanded; | |
456 | ||
457 | /* Set the certificate and private keys */ | |
458 | ||
459 | if (cert_expanded != NULL) | |
460 | { | |
461 | DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", | |
462 | cert_expanded, key_expanded); | |
463 | rc = gnutls_certificate_set_x509_key_file(x509_cred, CS cert_expanded, | |
464 | CS key_expanded, GNUTLS_X509_FMT_PEM); | |
8e669ac1 | 465 | if (rc < 0) |
de365ded PH |
466 | { |
467 | uschar *msg = string_sprintf("cert/key setup: cert=%s key=%s", | |
8e669ac1 | 468 | cert_expanded, key_expanded); |
de365ded | 469 | return tls_error(msg, host, rc); |
8e669ac1 | 470 | } |
059ec3d9 PH |
471 | } |
472 | ||
473 | /* A certificate is mandatory in a server, but not in a client */ | |
474 | ||
475 | else | |
476 | { | |
477 | if (host == NULL) | |
478 | return tls_error(US"no TLS server certificate is specified", host, 0); | |
479 | DEBUG(D_tls) debug_printf("no TLS client certificate is specified\n"); | |
480 | } | |
481 | ||
482 | /* Set the trusted CAs file if one is provided, and then add the CRL if one is | |
483 | provided. Experiment shows that, if the certificate file is empty, an unhelpful | |
484 | error message is provided. However, if we just refrain from setting anything up | |
485 | in that case, certificate verification fails, which seems to be the correct | |
486 | behaviour. */ | |
487 | ||
488 | if (cas != NULL) | |
489 | { | |
490 | struct stat statbuf; | |
491 | ||
492 | if (!expand_check(cas, US"tls_verify_certificates", &cas_expanded)) | |
493 | return DEFER; | |
494 | ||
495 | if (stat(CS cas_expanded, &statbuf) < 0) | |
496 | { | |
497 | log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " | |
498 | "(tls_verify_certificates): %s", cas_expanded, strerror(errno)); | |
499 | return DEFER; | |
500 | } | |
501 | ||
502 | DEBUG(D_tls) debug_printf("verify certificates = %s size=%d\n", | |
503 | cas_expanded, (int)statbuf.st_size); | |
504 | ||
505 | /* If the cert file is empty, there's no point in loading the CRL file. */ | |
506 | ||
507 | if (statbuf.st_size > 0) | |
508 | { | |
509 | rc = gnutls_certificate_set_x509_trust_file(x509_cred, CS cas_expanded, | |
510 | GNUTLS_X509_FMT_PEM); | |
511 | if (rc < 0) return tls_error(US"setup_certs", host, rc); | |
512 | ||
513 | if (crl != NULL && *crl != 0) | |
514 | { | |
515 | if (!expand_check(crl, US"tls_crl", &crl_expanded)) | |
516 | return DEFER; | |
517 | DEBUG(D_tls) debug_printf("loading CRL file = %s\n", crl_expanded); | |
518 | rc = gnutls_certificate_set_x509_crl_file(x509_cred, CS crl_expanded, | |
519 | GNUTLS_X509_FMT_PEM); | |
520 | if (rc < 0) return tls_error(US"CRL setup", host, rc); | |
521 | } | |
522 | } | |
523 | } | |
524 | ||
525 | /* Associate the parameters with the x509 credentials structure. */ | |
526 | ||
527 | gnutls_certificate_set_dh_params(x509_cred, dh_params); | |
b5aea5e1 | 528 | gnutls_certificate_set_rsa_export_params(x509_cred, rsa_params); |
059ec3d9 PH |
529 | |
530 | DEBUG(D_tls) debug_printf("initialized certificate stuff\n"); | |
531 | return OK; | |
532 | } | |
533 | ||
534 | ||
535 | ||
536 | ||
537 | /************************************************* | |
538 | * Remove ciphers from priority list * | |
539 | *************************************************/ | |
540 | ||
541 | /* Cautiously written so that it will remove duplicates if present. | |
542 | ||
543 | Arguments: | |
544 | list a zero-terminated list | |
545 | remove_list a zero-terminated list to be removed | |
546 | ||
547 | Returns: nothing | |
548 | */ | |
549 | ||
550 | static void | |
551 | remove_ciphers(int *list, int *remove_list) | |
552 | { | |
553 | for (; *remove_list != 0; remove_list++) | |
554 | { | |
555 | int *p = list; | |
556 | while (*p != 0) | |
557 | { | |
558 | if (*p == *remove_list) | |
559 | { | |
560 | int *pp = p; | |
561 | do { pp[0] = pp[1]; pp++; } while (*pp != 0); | |
562 | } | |
563 | else p++; | |
564 | } | |
565 | } | |
566 | } | |
567 | ||
568 | ||
569 | ||
570 | /************************************************* | |
571 | * Add ciphers to priority list * | |
572 | *************************************************/ | |
573 | ||
574 | /* Cautiously written to check the list size | |
575 | ||
576 | Arguments: | |
577 | list a zero-terminated list | |
578 | list_max maximum offset in the list | |
579 | add_list a zero-terminated list to be added | |
580 | ||
581 | Returns: TRUE if OK; FALSE if list overflows | |
582 | */ | |
583 | ||
584 | static BOOL | |
585 | add_ciphers(int *list, int list_max, int *add_list) | |
586 | { | |
587 | int next = 0; | |
588 | while (list[next] != 0) next++; | |
589 | while (*add_list != 0) | |
590 | { | |
591 | if (next >= list_max) return FALSE; | |
592 | list[next++] = *add_list++; | |
593 | } | |
594 | list[next] = 0; | |
595 | return TRUE; | |
596 | } | |
597 | ||
598 | ||
599 | ||
600 | /************************************************* | |
601 | * Initialize a single GNUTLS session * | |
602 | *************************************************/ | |
603 | ||
604 | /* Set the algorithm, the db backend, whether to request certificates etc. | |
605 | ||
606 | TLS in Exim was first implemented using OpenSSL. This has a function to which | |
607 | you pass a list of cipher suites that are permitted/not permitted. GnuTLS works | |
608 | differently. It operates using priority lists for the different components of | |
609 | cipher suites. | |
610 | ||
611 | For compatibility of configuration, we scan a list of cipher suites and set | |
612 | priorities therefrom. However, at the moment, we pay attention only to the bulk | |
613 | cipher. | |
614 | ||
615 | Arguments: | |
616 | side one of GNUTLS_SERVER, GNUTLS_CLIENT | |
617 | expciphers expanded ciphers list | |
618 | ||
619 | Returns: a gnutls_session, or NULL if there is a problem | |
620 | */ | |
621 | ||
622 | static gnutls_session | |
623 | tls_session_init(int side, uschar *expciphers) | |
624 | { | |
625 | gnutls_session session; | |
626 | ||
627 | gnutls_init(&session, side); | |
628 | ||
629 | /* Handle the list of permitted ciphers */ | |
630 | ||
631 | memcpy(cipher_priority, default_cipher_priority, sizeof(cipher_priority)); | |
632 | ||
633 | if (expciphers != NULL) | |
634 | { | |
635 | int sep = 0; | |
636 | BOOL first = TRUE; | |
637 | uschar *cipher; | |
638 | ||
639 | /* The names OpenSSL uses are of the form DES-CBC3-SHA, using hyphen | |
640 | separators. GnuTLS uses underscore separators. So that I can use either form | |
641 | in my tests, and also for general convenience, we turn hyphens into | |
642 | underscores before scanning the list. */ | |
643 | ||
644 | uschar *s = expciphers; | |
645 | while (*s != 0) { if (*s == '-') *s = '_'; s++; } | |
646 | ||
647 | while ((cipher = string_nextinlist(&expciphers, &sep, big_buffer, | |
648 | big_buffer_size)) != NULL) | |
649 | { | |
650 | int i; | |
651 | BOOL exclude = cipher[0] == '!'; | |
652 | if (first && !exclude) cipher_priority[0] = 0; | |
653 | first = FALSE; | |
654 | ||
655 | for (i = 0; i < sizeof(cipher_index)/sizeof(pri_item); i++) | |
656 | { | |
657 | uschar *ss = strstric(cipher, cipher_index[i].name, FALSE); | |
658 | if (ss != NULL) | |
659 | { | |
660 | uschar *endss = ss + Ustrlen(cipher_index[i].name); | |
661 | if ((ss == cipher || !isalnum(ss[-1])) && !isalnum(*endss)) | |
662 | { | |
663 | if (exclude) | |
664 | remove_ciphers(cipher_priority, cipher_index[i].values); | |
665 | else | |
666 | { | |
667 | if (!add_ciphers(cipher_priority, | |
668 | sizeof(cipher_priority)/sizeof(pri_item), | |
669 | cipher_index[i].values)) | |
670 | { | |
671 | log_write(0, LOG_MAIN|LOG_PANIC, "GnuTLS init failed: cipher " | |
672 | "priority table overflow"); | |
673 | gnutls_deinit(session); | |
674 | return NULL; | |
675 | } | |
676 | } | |
677 | } | |
678 | } | |
679 | } | |
680 | } | |
681 | ||
682 | DEBUG(D_tls) | |
683 | { | |
684 | int *ptr = cipher_priority; | |
685 | debug_printf("adjusted cipher priorities:"); | |
686 | while (*ptr != 0) debug_printf(" %d", *ptr++); | |
687 | debug_printf("\n"); | |
688 | } | |
689 | } | |
690 | ||
691 | /* Define the various priorities */ | |
692 | ||
693 | gnutls_cipher_set_priority(session, cipher_priority); | |
694 | gnutls_compression_set_priority(session, comp_priority); | |
695 | gnutls_kx_set_priority(session, kx_priority); | |
696 | gnutls_protocol_set_priority(session, protocol_priority); | |
697 | gnutls_mac_set_priority(session, mac_priority); | |
698 | ||
699 | gnutls_cred_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred); | |
700 | ||
701 | gnutls_dh_set_prime_bits(session, DH_BITS); | |
702 | ||
703 | /* Request or demand a certificate of the peer, as configured. This will | |
704 | happen only in a server. */ | |
705 | ||
706 | if (verify_requirement != VERIFY_NONE) | |
707 | gnutls_certificate_server_set_request(session, | |
708 | (verify_requirement == VERIFY_OPTIONAL)? | |
709 | GNUTLS_CERT_REQUEST : GNUTLS_CERT_REQUIRE); | |
710 | ||
711 | gnutls_db_set_cache_expiration(session, ssl_session_timeout); | |
712 | ||
713 | DEBUG(D_tls) debug_printf("initialized GnuTLS session\n"); | |
714 | return session; | |
715 | } | |
716 | ||
717 | ||
718 | ||
719 | /************************************************* | |
720 | * Get name of cipher in use * | |
721 | *************************************************/ | |
722 | ||
723 | /* The answer is left in a static buffer, and tls_cipher is set to point | |
724 | to it. | |
725 | ||
726 | Argument: pointer to a GnuTLS session | |
727 | Returns: nothing | |
728 | */ | |
729 | ||
730 | static void | |
731 | construct_cipher_name(gnutls_session session) | |
732 | { | |
733 | static uschar cipherbuf[256]; | |
734 | uschar *ver; | |
735 | int bits, c, kx, mac; | |
736 | ||
737 | ver = string_copy( | |
738 | US gnutls_protocol_get_name(gnutls_protocol_get_version(session))); | |
739 | if (Ustrncmp(ver, "TLS ", 4) == 0) ver[3] = '-'; /* Don't want space */ | |
740 | ||
741 | c = gnutls_cipher_get(session); | |
742 | bits = gnutls_cipher_get_key_size(c); | |
743 | ||
744 | mac = gnutls_mac_get(session); | |
745 | kx = gnutls_kx_get(session); | |
746 | ||
747 | string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver, | |
748 | gnutls_cipher_suite_get_name(kx, c, mac), bits); | |
749 | tls_cipher = cipherbuf; | |
750 | ||
751 | DEBUG(D_tls) debug_printf("cipher: %s\n", cipherbuf); | |
752 | } | |
753 | ||
754 | ||
755 | ||
756 | /************************************************* | |
757 | * Start a TLS session in a server * | |
758 | *************************************************/ | |
759 | ||
760 | /* This is called when Exim is running as a server, after having received | |
761 | the STARTTLS command. It must respond to that command, and then negotiate | |
762 | a TLS session. | |
763 | ||
764 | Arguments: | |
765 | require_ciphers list of allowed ciphers | |
766 | ||
767 | Returns: OK on success | |
768 | DEFER for errors before the start of the negotiation | |
769 | FAIL for errors during the negotation; the server can't | |
770 | continue running. | |
771 | */ | |
772 | ||
773 | int | |
774 | tls_server_start(uschar *require_ciphers) | |
775 | { | |
776 | int rc; | |
777 | uschar *error; | |
778 | uschar *expciphers = NULL; | |
779 | ||
780 | /* Check for previous activation */ | |
781 | ||
782 | if (tls_active >= 0) | |
783 | { | |
784 | log_write(0, LOG_MAIN, "STARTTLS received in already encrypted " | |
785 | "connection from %s", | |
786 | (sender_fullhost != NULL)? sender_fullhost : US"local process"); | |
787 | smtp_printf("554 Already in TLS\r\n"); | |
788 | return FAIL; | |
789 | } | |
790 | ||
791 | /* Initialize the library. If it fails, it will already have logged the error | |
792 | and sent an SMTP response. */ | |
793 | ||
794 | DEBUG(D_tls) debug_printf("initializing GnuTLS as a server\n"); | |
795 | ||
796 | rc = tls_init(NULL, tls_certificate, tls_privatekey, tls_verify_certificates, | |
797 | tls_crl); | |
798 | if (rc != OK) return rc; | |
799 | ||
800 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
801 | return FAIL; | |
802 | ||
803 | /* If this is a host for which certificate verification is mandatory or | |
804 | optional, set up appropriately. */ | |
805 | ||
806 | tls_certificate_verified = FALSE; | |
807 | verify_requirement = VERIFY_NONE; | |
808 | ||
809 | if (verify_check_host(&tls_verify_hosts) == OK) | |
810 | verify_requirement = VERIFY_REQUIRED; | |
811 | else if (verify_check_host(&tls_try_verify_hosts) == OK) | |
812 | verify_requirement = VERIFY_OPTIONAL; | |
813 | ||
814 | /* Prepare for new connection */ | |
815 | ||
816 | tls_session = tls_session_init(GNUTLS_SERVER, expciphers); | |
817 | if (tls_session == NULL) | |
818 | return tls_error(US"tls_session_init", NULL, GNUTLS_E_MEMORY_ERROR); | |
819 | ||
820 | /* Set context and tell client to go ahead, except in the case of TLS startup | |
821 | on connection, where outputting anything now upsets the clients and tends to | |
822 | make them disconnect. We need to have an explicit fflush() here, to force out | |
823 | the response. Other smtp_printf() calls do not need it, because in non-TLS | |
824 | mode, the fflush() happens when smtp_getc() is called. */ | |
825 | ||
826 | if (!tls_on_connect) | |
827 | { | |
828 | smtp_printf("220 TLS go ahead\r\n"); | |
829 | fflush(smtp_out); | |
830 | } | |
831 | ||
832 | /* Now negotiate the TLS session. We put our own timer on it, since it seems | |
833 | that the GnuTLS library doesn't. */ | |
834 | ||
835 | gnutls_transport_set_ptr(tls_session, (gnutls_transport_ptr)fileno(smtp_out)); | |
836 | ||
837 | sigalrm_seen = FALSE; | |
838 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
839 | rc = gnutls_handshake(tls_session); | |
840 | alarm(0); | |
841 | ||
842 | if (rc < 0) | |
843 | { | |
844 | if (sigalrm_seen) | |
845 | Ustrcpy(ssl_errstring, "timed out"); | |
846 | else | |
847 | Ustrcpy(ssl_errstring, gnutls_strerror(rc)); | |
848 | log_write(0, LOG_MAIN, | |
849 | "TLS error on connection from %s (gnutls_handshake): %s", | |
850 | (sender_fullhost != NULL)? sender_fullhost : US"local process", | |
851 | ssl_errstring); | |
852 | ||
853 | /* It seems that, except in the case of a timeout, we have to close the | |
854 | connection right here; otherwise if the other end is running OpenSSL it hangs | |
855 | until the server times out. */ | |
856 | ||
857 | if (!sigalrm_seen) | |
858 | { | |
859 | fclose(smtp_out); | |
860 | fclose(smtp_in); | |
861 | } | |
862 | ||
863 | return FAIL; | |
864 | } | |
865 | ||
866 | DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); | |
867 | ||
868 | if (verify_requirement != VERIFY_NONE && | |
869 | !verify_certificate(tls_session, &error)) | |
870 | { | |
871 | log_write(0, LOG_MAIN, | |
872 | "TLS error on connection from %s: certificate verification failed (%s)", | |
873 | (sender_fullhost != NULL)? sender_fullhost : US"local process", error); | |
874 | return FAIL; | |
875 | } | |
876 | ||
877 | construct_cipher_name(tls_session); | |
878 | ||
879 | /* TLS has been set up. Adjust the input functions to read via TLS, | |
880 | and initialize appropriately. */ | |
881 | ||
882 | ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); | |
883 | ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; | |
884 | ssl_xfer_eof = ssl_xfer_error = 0; | |
885 | ||
886 | receive_getc = tls_getc; | |
887 | receive_ungetc = tls_ungetc; | |
888 | receive_feof = tls_feof; | |
889 | receive_ferror = tls_ferror; | |
890 | ||
891 | tls_active = fileno(smtp_out); | |
892 | ||
893 | return OK; | |
894 | } | |
895 | ||
896 | ||
897 | ||
898 | ||
899 | /************************************************* | |
900 | * Start a TLS session in a client * | |
901 | *************************************************/ | |
902 | ||
903 | /* Called from the smtp transport after STARTTLS has been accepted. | |
904 | ||
905 | Arguments: | |
906 | fd the fd of the connection | |
907 | host connected host (for messages) | |
908 | addr | |
909 | dhparam DH parameter file | |
910 | certificate certificate file | |
911 | privatekey private key file | |
912 | verify_certs file for certificate verify | |
913 | verify_crl CRL for verify | |
914 | require_ciphers list of allowed ciphers | |
915 | timeout startup timeout | |
916 | ||
917 | Returns: OK/DEFER/FAIL (because using common functions), | |
918 | but for a client, DEFER and FAIL have the same meaning | |
919 | */ | |
920 | ||
921 | int | |
922 | tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, | |
923 | uschar *certificate, uschar *privatekey, uschar *verify_certs, | |
924 | uschar *verify_crl, uschar *require_ciphers, int timeout) | |
925 | { | |
926 | const gnutls_datum *server_certs; | |
927 | uschar *expciphers = NULL; | |
928 | uschar *error; | |
929 | unsigned int server_certs_size; | |
930 | int rc; | |
931 | ||
932 | DEBUG(D_tls) debug_printf("initializing GnuTLS as a client\n"); | |
933 | ||
934 | client_host = host; | |
935 | verify_requirement = (verify_certs == NULL)? VERIFY_NONE : VERIFY_REQUIRED; | |
936 | rc = tls_init(host, certificate, privatekey, verify_certs, verify_crl); | |
937 | if (rc != OK) return rc; | |
938 | ||
939 | if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) | |
940 | return FAIL; | |
941 | ||
942 | tls_session = tls_session_init(GNUTLS_CLIENT, expciphers); | |
943 | if (tls_session == NULL) | |
944 | return tls_error(US "tls_session_init", host, GNUTLS_E_MEMORY_ERROR); | |
945 | ||
946 | gnutls_transport_set_ptr(tls_session, (gnutls_transport_ptr)fd); | |
947 | ||
948 | /* There doesn't seem to be a built-in timeout on connection. */ | |
949 | ||
950 | sigalrm_seen = FALSE; | |
951 | alarm(timeout); | |
952 | rc = gnutls_handshake(tls_session); | |
953 | alarm(0); | |
954 | ||
955 | if (rc < 0) | |
956 | { | |
957 | if (sigalrm_seen) | |
958 | { | |
959 | log_write(0, LOG_MAIN, "TLS error on connection to %s [%s]: " | |
960 | "gnutls_handshake timed out", host->name, host->address); | |
961 | return FAIL; | |
962 | } | |
963 | else return tls_error(US "gnutls_handshake", host, rc); | |
964 | } | |
965 | ||
966 | server_certs = gnutls_certificate_get_peers(tls_session, &server_certs_size); | |
967 | ||
968 | if (server_certs != NULL) | |
969 | { | |
970 | uschar buff[1024]; | |
971 | gnutls_x509_crt gcert; | |
972 | ||
973 | gnutls_x509_crt_init(&gcert); | |
974 | tls_peerdn = US"unknown"; | |
975 | ||
976 | if (gnutls_x509_crt_import(gcert, server_certs, GNUTLS_X509_FMT_DER) == 0) | |
977 | { | |
978 | size_t bufsize = sizeof(buff); | |
979 | if (gnutls_x509_crt_get_dn(gcert, CS buff, &bufsize) >= 0) | |
980 | tls_peerdn = string_copy_malloc(buff); | |
981 | } | |
982 | } | |
983 | ||
984 | /* Should we also verify the hostname here? */ | |
985 | ||
986 | if (verify_requirement != VERIFY_NONE && | |
987 | !verify_certificate(tls_session, &error)) | |
988 | { | |
989 | log_write(0, LOG_MAIN, | |
990 | "TLS error on connection to %s [%s]: certificate verification failed (%s)", | |
991 | host->name, host->address, error); | |
992 | return FAIL; | |
993 | } | |
994 | ||
995 | construct_cipher_name(tls_session); /* Sets tls_cipher */ | |
996 | tls_active = fd; | |
997 | return OK; | |
998 | } | |
999 | ||
1000 | ||
1001 | ||
1002 | /************************************************* | |
1003 | * Deal with logging errors during I/O * | |
1004 | *************************************************/ | |
1005 | ||
1006 | /* We have to get the identity of the peer from saved data. | |
1007 | ||
1008 | Argument: | |
1009 | ec the GnuTLS error code, or 0 if it's a local error | |
1010 | when text identifying read or write | |
1011 | text local error text when ec is 0 | |
1012 | ||
1013 | Returns: nothing | |
1014 | */ | |
1015 | ||
1016 | static void | |
1017 | record_io_error(int ec, uschar *when, uschar *text) | |
1018 | { | |
1019 | uschar *additional = US""; | |
1020 | ||
1021 | if (ec == GNUTLS_E_FATAL_ALERT_RECEIVED) | |
1022 | additional = string_sprintf(": %s", | |
1023 | gnutls_alert_get_name(gnutls_alert_get(tls_session))); | |
1024 | ||
1025 | if (initialized == INITIALIZED_SERVER) | |
1026 | log_write(0, LOG_MAIN, "TLS %s error on connection from %s: %s%s", when, | |
1027 | (sender_fullhost != NULL)? sender_fullhost : US "local process", | |
1028 | (ec == 0)? text : US gnutls_strerror(ec), additional); | |
1029 | ||
1030 | else | |
1031 | log_write(0, LOG_MAIN, "TLS %s error on connection to %s [%s]: %s%s", when, | |
1032 | client_host->name, client_host->address, | |
1033 | (ec == 0)? text : US gnutls_strerror(ec), additional); | |
1034 | } | |
1035 | ||
1036 | ||
1037 | ||
1038 | /************************************************* | |
1039 | * TLS version of getc * | |
1040 | *************************************************/ | |
1041 | ||
1042 | /* This gets the next byte from the TLS input buffer. If the buffer is empty, | |
1043 | it refills the buffer via the GnuTLS reading function. | |
1044 | ||
1045 | Arguments: none | |
1046 | Returns: the next character or EOF | |
1047 | */ | |
1048 | ||
1049 | int | |
1050 | tls_getc(void) | |
1051 | { | |
1052 | if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) | |
1053 | { | |
1054 | int inbytes; | |
1055 | ||
1056 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%lx, %lx, %u)\n", | |
1057 | (long) tls_session, (long) ssl_xfer_buffer, ssl_xfer_buffer_size); | |
1058 | ||
1059 | if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); | |
1060 | inbytes = gnutls_record_recv(tls_session, CS ssl_xfer_buffer, | |
1061 | ssl_xfer_buffer_size); | |
1062 | alarm(0); | |
1063 | ||
1064 | /* A zero-byte return appears to mean that the TLS session has been | |
1065 | closed down, not that the socket itself has been closed down. Revert to | |
1066 | non-TLS handling. */ | |
1067 | ||
1068 | if (inbytes == 0) | |
1069 | { | |
1070 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1071 | ||
1072 | receive_getc = smtp_getc; | |
1073 | receive_ungetc = smtp_ungetc; | |
1074 | receive_feof = smtp_feof; | |
1075 | receive_ferror = smtp_ferror; | |
1076 | ||
1077 | gnutls_deinit(tls_session); | |
1078 | tls_session = NULL; | |
1079 | tls_active = -1; | |
1080 | tls_cipher = NULL; | |
1081 | tls_peerdn = NULL; | |
1082 | ||
1083 | return smtp_getc(); | |
1084 | } | |
1085 | ||
1086 | /* Handle genuine errors */ | |
1087 | ||
1088 | else if (inbytes < 0) | |
1089 | { | |
1090 | record_io_error(inbytes, US"recv", NULL); | |
1091 | ssl_xfer_error = 1; | |
1092 | return EOF; | |
1093 | } | |
1094 | ||
1095 | ssl_xfer_buffer_hwm = inbytes; | |
1096 | ssl_xfer_buffer_lwm = 0; | |
1097 | } | |
1098 | ||
1099 | ||
1100 | /* Something in the buffer; return next uschar */ | |
1101 | ||
1102 | return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; | |
1103 | } | |
1104 | ||
1105 | ||
1106 | ||
1107 | /************************************************* | |
1108 | * Read bytes from TLS channel * | |
1109 | *************************************************/ | |
1110 | ||
1111 | /* | |
1112 | Arguments: | |
1113 | buff buffer of data | |
1114 | len size of buffer | |
1115 | ||
1116 | Returns: the number of bytes read | |
1117 | -1 after a failed read | |
1118 | */ | |
1119 | ||
1120 | int | |
1121 | tls_read(uschar *buff, size_t len) | |
1122 | { | |
1123 | int inbytes; | |
1124 | ||
1125 | DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%lx, %lx, %u)\n", | |
1126 | (long) tls_session, (long) buff, len); | |
1127 | ||
1128 | inbytes = gnutls_record_recv(tls_session, CS buff, len); | |
1129 | if (inbytes > 0) return inbytes; | |
1130 | if (inbytes == 0) | |
1131 | { | |
1132 | DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); | |
1133 | } | |
1134 | else record_io_error(inbytes, US"recv", NULL); | |
1135 | ||
1136 | return -1; | |
1137 | } | |
1138 | ||
1139 | ||
1140 | ||
1141 | /************************************************* | |
1142 | * Write bytes down TLS channel * | |
1143 | *************************************************/ | |
1144 | ||
1145 | /* | |
1146 | Arguments: | |
1147 | buff buffer of data | |
1148 | len number of bytes | |
1149 | ||
1150 | Returns: the number of bytes after a successful write, | |
1151 | -1 after a failed write | |
1152 | */ | |
1153 | ||
1154 | int | |
1155 | tls_write(const uschar *buff, size_t len) | |
1156 | { | |
1157 | int outbytes; | |
1158 | int left = len; | |
1159 | ||
1160 | DEBUG(D_tls) debug_printf("tls_do_write(%lx, %d)\n", (long) buff, left); | |
1161 | while (left > 0) | |
1162 | { | |
1163 | DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %lx, %d)\n", (long)buff, | |
1164 | left); | |
1165 | outbytes = gnutls_record_send(tls_session, CS buff, left); | |
1166 | ||
1167 | DEBUG(D_tls) debug_printf("outbytes=%d\n", outbytes); | |
1168 | if (outbytes < 0) | |
1169 | { | |
1170 | record_io_error(outbytes, US"send", NULL); | |
1171 | return -1; | |
1172 | } | |
1173 | if (outbytes == 0) | |
1174 | { | |
1175 | record_io_error(0, US"send", US"TLS channel closed on write"); | |
1176 | return -1; | |
1177 | } | |
1178 | ||
1179 | left -= outbytes; | |
1180 | buff += outbytes; | |
1181 | } | |
1182 | ||
1183 | return len; | |
1184 | } | |
1185 | ||
1186 | ||
1187 | ||
1188 | /************************************************* | |
1189 | * Close down a TLS session * | |
1190 | *************************************************/ | |
1191 | ||
1192 | /* This is also called from within a delivery subprocess forked from the | |
1193 | daemon, to shut down the TLS library, without actually doing a shutdown (which | |
1194 | would tamper with the TLS session in the parent process). | |
1195 | ||
1196 | Arguments: TRUE if gnutls_bye is to be called | |
1197 | Returns: nothing | |
1198 | */ | |
1199 | ||
1200 | void | |
1201 | tls_close(BOOL shutdown) | |
1202 | { | |
1203 | if (tls_active < 0) return; /* TLS was not active */ | |
1204 | ||
1205 | if (shutdown) | |
1206 | { | |
1207 | DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); | |
1208 | gnutls_bye(tls_session, GNUTLS_SHUT_WR); | |
1209 | } | |
1210 | ||
1211 | gnutls_deinit(tls_session); | |
1212 | tls_session = NULL; | |
1213 | gnutls_global_deinit(); | |
1214 | ||
1215 | tls_active = -1; | |
1216 | } | |
1217 | ||
1218 | /* End of tls-gnu.c */ |