d00258b9e250dcbe0734f2f8079a0a5941051ebb
[exim.git] / src / src / tlscert-gnu.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) Jeremy Harris 2014 - 2015 */
6
7 /* This file provides TLS/SSL support for Exim using the GnuTLS library,
8 one of the available supported implementations. This file is #included into
9 tls.c when USE_GNUTLS has been set.
10 */
11
12 #include <gnutls/gnutls.h>
13 /* needed for cert checks in verification and DN extraction: */
14 #include <gnutls/x509.h>
15 /* needed to disable PKCS11 autoload unless requested */
16 #if GNUTLS_VERSION_NUMBER >= 0x020c00
17 # include <gnutls/pkcs11.h>
18 #endif
19
20
21 /*****************************************************
22 * Export/import a certificate, binary/printable
23 *****************************************************/
24 int
25 tls_export_cert(uschar * buf, size_t buflen, void * cert)
26 {
27 size_t sz = buflen;
28 void * reset_point = store_get(0);
29 int fail;
30 const uschar * cp;
31
32 if ((fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
33 GNUTLS_X509_FMT_PEM, buf, &sz)))
34 {
35 log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
36 gnutls_strerror(fail));
37 return 1;
38 }
39 if ((cp = string_printing(buf)) != buf)
40 {
41 Ustrncpy(buf, cp, buflen);
42 if (buf[buflen-1])
43 fail = 1;
44 }
45 store_reset(reset_point);
46 return fail;
47 }
48
49 int
50 tls_import_cert(const uschar * buf, void ** cert)
51 {
52 void * reset_point = store_get(0);
53 gnutls_datum_t datum;
54 gnutls_x509_crt_t crt = *(gnutls_x509_crt_t *)cert;
55 int fail = 0;
56
57 if (crt)
58 gnutls_x509_crt_deinit(crt);
59 else
60 gnutls_global_init();
61
62 gnutls_x509_crt_init(&crt);
63
64 datum.data = string_unprinting(US buf);
65 datum.size = Ustrlen(datum.data);
66 if ((fail = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM)))
67 {
68 log_write(0, LOG_MAIN, "TLS error in certificate import: %s",
69 gnutls_strerror(fail));
70 fail = 1;
71 }
72 else
73 *cert = (void *)crt;
74
75 store_reset(reset_point);
76 return fail;
77 }
78
79 void
80 tls_free_cert(void ** cert)
81 {
82 gnutls_x509_crt_t crt = *(gnutls_x509_crt_t *)cert;
83 if (crt)
84 {
85 gnutls_x509_crt_deinit(crt);
86 gnutls_global_deinit();
87 *cert = NULL;
88 }
89 }
90
91 /*****************************************************
92 * Certificate field extraction routines
93 *****************************************************/
94
95 /* First, some internal service functions */
96
97 static uschar *
98 g_err(const char * tag, const char * from, int gnutls_err)
99 {
100 expand_string_message = string_sprintf("%s: %s fail: %s\n",
101 from, tag, gnutls_strerror(gnutls_err));
102 return NULL;
103 }
104
105
106 static uschar *
107 time_copy(time_t t, uschar * mod)
108 {
109 uschar * cp;
110 size_t len = 32;
111
112 if (mod && Ustrcmp(mod, "int") == 0)
113 return string_sprintf("%u", (unsigned)t);
114
115 cp = store_get(len);
116 if (timestamps_utc)
117 {
118 uschar * tz = to_tz(US"GMT0");
119 len = strftime(CS cp, len, "%b %e %T %Y %Z", gmtime(&t));
120 restore_tz(tz);
121 }
122 else
123 len = strftime(CS cp, len, "%b %e %T %Y %Z", localtime(&t));
124 return len > 0 ? cp : NULL;
125 }
126
127
128 /**/
129 /* Now the extractors, called from expand.c
130 Arguments:
131 cert The certificate
132 mod Optional modifiers for the operator
133
134 Return:
135 Allocated string with extracted value
136 */
137
138 uschar *
139 tls_cert_issuer(void * cert, uschar * mod)
140 {
141 uschar * cp = NULL;
142 int ret;
143 size_t siz = 0;
144
145 if ((ret = gnutls_x509_crt_get_issuer_dn(cert, cp, &siz))
146 != GNUTLS_E_SHORT_MEMORY_BUFFER)
147 return g_err("gi0", __FUNCTION__, ret);
148
149 cp = store_get(siz);
150 if ((ret = gnutls_x509_crt_get_issuer_dn(cert, cp, &siz)) < 0)
151 return g_err("gi1", __FUNCTION__, ret);
152
153 return mod ? tls_field_from_dn(cp, mod) : cp;
154 }
155
156 uschar *
157 tls_cert_not_after(void * cert, uschar * mod)
158 {
159 return time_copy(
160 gnutls_x509_crt_get_expiration_time((gnutls_x509_crt_t)cert),
161 mod);
162 }
163
164 uschar *
165 tls_cert_not_before(void * cert, uschar * mod)
166 {
167 return time_copy(
168 gnutls_x509_crt_get_activation_time((gnutls_x509_crt_t)cert),
169 mod);
170 }
171
172 uschar *
173 tls_cert_serial_number(void * cert, uschar * mod)
174 {
175 uschar bin[50], txt[150];
176 size_t sz = sizeof(bin);
177 uschar * sp;
178 uschar * dp;
179 int ret;
180
181 if ((ret = gnutls_x509_crt_get_serial((gnutls_x509_crt_t)cert,
182 bin, &sz)))
183 return g_err("gs0", __FUNCTION__, ret);
184
185 for(dp = txt, sp = bin; sz; dp += 2, sp++, sz--)
186 sprintf(dp, "%.2x", *sp);
187 for(sp = txt; sp[0]=='0' && sp[1]; ) sp++; /* leading zeroes */
188 return string_copy(sp);
189 }
190
191 uschar *
192 tls_cert_signature(void * cert, uschar * mod)
193 {
194 uschar * cp1 = NULL;
195 uschar * cp2;
196 uschar * cp3;
197 size_t len = 0;
198 int ret;
199
200 if ((ret = gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, cp1, &len))
201 != GNUTLS_E_SHORT_MEMORY_BUFFER)
202 return g_err("gs0", __FUNCTION__, ret);
203
204 cp1 = store_get(len*4+1);
205 if (gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, cp1, &len) != 0)
206 return g_err("gs1", __FUNCTION__, ret);
207
208 for(cp3 = cp2 = cp1+len; cp1 < cp2; cp3 += 3, cp1++)
209 sprintf(cp3, "%.2x ", *cp1);
210 cp3[-1]= '\0';
211
212 return cp2;
213 }
214
215 uschar *
216 tls_cert_signature_algorithm(void * cert, uschar * mod)
217 {
218 gnutls_sign_algorithm_t algo =
219 gnutls_x509_crt_get_signature_algorithm((gnutls_x509_crt_t)cert);
220 return algo < 0 ? NULL : string_copy(gnutls_sign_get_name(algo));
221 }
222
223 uschar *
224 tls_cert_subject(void * cert, uschar * mod)
225 {
226 uschar * cp = NULL;
227 int ret;
228 size_t siz = 0;
229
230 if ((ret = gnutls_x509_crt_get_dn(cert, cp, &siz))
231 != GNUTLS_E_SHORT_MEMORY_BUFFER)
232 return g_err("gs0", __FUNCTION__, ret);
233
234 cp = store_get(siz);
235 if ((ret = gnutls_x509_crt_get_dn(cert, cp, &siz)) < 0)
236 return g_err("gs1", __FUNCTION__, ret);
237
238 return mod ? tls_field_from_dn(cp, mod) : cp;
239 }
240
241 uschar *
242 tls_cert_version(void * cert, uschar * mod)
243 {
244 return string_sprintf("%d", gnutls_x509_crt_get_version(cert));
245 }
246
247 uschar *
248 tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
249 {
250 uschar * cp1 = NULL;
251 uschar * cp2;
252 uschar * cp3;
253 size_t siz = 0;
254 unsigned int crit;
255 int ret;
256
257 ret = gnutls_x509_crt_get_extension_by_oid ((gnutls_x509_crt_t)cert,
258 oid, idx, cp1, &siz, &crit);
259 if (ret != GNUTLS_E_SHORT_MEMORY_BUFFER)
260 return g_err("ge0", __FUNCTION__, ret);
261
262 cp1 = store_get(siz*4 + 1);
263
264 ret = gnutls_x509_crt_get_extension_by_oid ((gnutls_x509_crt_t)cert,
265 oid, idx, cp1, &siz, &crit);
266 if (ret < 0)
267 return g_err("ge1", __FUNCTION__, ret);
268
269 /* binary data, DER encoded */
270
271 /* just dump for now */
272 for(cp3 = cp2 = cp1+siz; cp1 < cp2; cp3 += 3, cp1++)
273 sprintf(cp3, "%.2x ", *cp1);
274 cp3[-1]= '\0';
275
276 return cp2;
277 }
278
279 uschar *
280 tls_cert_subject_altname(void * cert, uschar * mod)
281 {
282 uschar * list = NULL;
283 int index;
284 size_t siz;
285 int ret;
286 uschar sep = '\n';
287 uschar * tag = US"";
288 uschar * ele;
289 int match = -1;
290
291 while (mod)
292 {
293 if (*mod == '>' && *++mod) sep = *mod++;
294 else if (Ustrcmp(mod, "dns")==0) { match = GNUTLS_SAN_DNSNAME; mod += 3; }
295 else if (Ustrcmp(mod, "uri")==0) { match = GNUTLS_SAN_URI; mod += 3; }
296 else if (Ustrcmp(mod, "mail")==0) { match = GNUTLS_SAN_RFC822NAME; mod += 4; }
297 else continue;
298
299 if (*mod++ != ',')
300 break;
301 }
302
303 for(index = 0;; index++)
304 {
305 siz = 0;
306 switch(ret = gnutls_x509_crt_get_subject_alt_name(
307 (gnutls_x509_crt_t)cert, index, NULL, &siz, NULL))
308 {
309 case GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE:
310 return list; /* no more elements; normal exit */
311
312 case GNUTLS_E_SHORT_MEMORY_BUFFER:
313 break;
314
315 default:
316 return g_err("gs0", __FUNCTION__, ret);
317 }
318
319 ele = store_get(siz+1);
320 if ((ret = gnutls_x509_crt_get_subject_alt_name(
321 (gnutls_x509_crt_t)cert, index, ele, &siz, NULL)) < 0)
322 return g_err("gs1", __FUNCTION__, ret);
323 ele[siz] = '\0';
324
325 if ( match != -1 && match != ret /* wrong type of SAN */
326 || Ustrlen(ele) != siz) /* contains a NUL */
327 continue;
328 switch (ret)
329 {
330 case GNUTLS_SAN_DNSNAME: tag = US"DNS"; break;
331 case GNUTLS_SAN_URI: tag = US"URI"; break;
332 case GNUTLS_SAN_RFC822NAME: tag = US"MAIL"; break;
333 default: continue; /* ignore unrecognised types */
334 }
335 list = string_append_listele(list, sep,
336 match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
337 }
338 /*NOTREACHED*/
339 }
340
341 uschar *
342 tls_cert_ocsp_uri(void * cert, uschar * mod)
343 {
344 #if GNUTLS_VERSION_NUMBER >= 0x030000
345 gnutls_datum_t uri;
346 int ret;
347 uschar sep = '\n';
348 int index;
349 uschar * list = NULL;
350
351 if (mod)
352 if (*mod == '>' && *++mod) sep = *mod++;
353
354 for(index = 0;; index++)
355 {
356 ret = gnutls_x509_crt_get_authority_info_access((gnutls_x509_crt_t)cert,
357 index, GNUTLS_IA_OCSP_URI, &uri, NULL);
358
359 if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
360 return list;
361 if (ret < 0)
362 return g_err("gai", __FUNCTION__, ret);
363
364 list = string_append_listele(list, sep,
365 string_copyn(uri.data, uri.size));
366 }
367 /*NOTREACHED*/
368
369 #else
370
371 expand_string_message =
372 string_sprintf("%s: OCSP support with GnuTLS requires version 3.0.0\n",
373 __FUNCTION__);
374 return NULL;
375
376 #endif
377 }
378
379 uschar *
380 tls_cert_crl_uri(void * cert, uschar * mod)
381 {
382 int ret;
383 size_t siz;
384 uschar sep = '\n';
385 int index;
386 uschar * list = NULL;
387 uschar * ele;
388
389 if (mod)
390 if (*mod == '>' && *++mod) sep = *mod++;
391
392 for(index = 0;; index++)
393 {
394 siz = 0;
395 switch(ret = gnutls_x509_crt_get_crl_dist_points(
396 (gnutls_x509_crt_t)cert, index, NULL, &siz, NULL, NULL))
397 {
398 case GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE:
399 return list;
400 case GNUTLS_E_SHORT_MEMORY_BUFFER:
401 break;
402 default:
403 return g_err("gc0", __FUNCTION__, ret);
404 }
405
406 ele = store_get(siz+1);
407 if ((ret = gnutls_x509_crt_get_crl_dist_points(
408 (gnutls_x509_crt_t)cert, index, ele, &siz, NULL, NULL)) < 0)
409 return g_err("gc1", __FUNCTION__, ret);
410
411 ele[siz] = '\0';
412 list = string_append_listele(list, sep, ele);
413 }
414 /*NOTREACHED*/
415 }
416
417
418 /*****************************************************
419 * Certificate operator routines
420 *****************************************************/
421 static uschar *
422 fingerprint(gnutls_x509_crt_t cert, gnutls_digest_algorithm_t algo)
423 {
424 int ret;
425 size_t siz = 0;
426 uschar * cp;
427 uschar * cp2;
428 uschar * cp3;
429
430 if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, NULL, &siz))
431 != GNUTLS_E_SHORT_MEMORY_BUFFER)
432 return g_err("gf0", __FUNCTION__, ret);
433
434 cp = store_get(siz*3+1);
435 if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, cp, &siz)) < 0)
436 return g_err("gf1", __FUNCTION__, ret);
437
438 for (cp3 = cp2 = cp+siz; cp < cp2; cp++, cp3+=2)
439 sprintf(cp3, "%02X",*cp);
440 return cp2;
441 }
442
443
444 uschar *
445 tls_cert_fprt_md5(void * cert)
446 {
447 return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_MD5);
448 }
449
450 uschar *
451 tls_cert_fprt_sha1(void * cert)
452 {
453 return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_SHA1);
454 }
455
456 uschar *
457 tls_cert_fprt_sha256(void * cert)
458 {
459 return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_SHA256);
460 }
461
462
463 /* vi: aw ai sw=2
464 */
465 /* End of tlscert-gnu.c */