TLS: support older GnuTLS versions
[exim.git] / src / src / tlscert-gnu.c
CommitLineData
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
3386088d 5/* Copyright (c) Jeremy Harris 2014 - 2015 */
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6
7/* This file provides TLS/SSL support for Exim using the GnuTLS library,
8one of the available supported implementations. This file is #included into
9tls.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*****************************************************/
24int
25tls_export_cert(uschar * buf, size_t buflen, void * cert)
26{
27size_t sz = buflen;
28void * reset_point = store_get(0);
c03fae8a 29int fail;
55414b25 30const uschar * cp;
9d1c15ef 31
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32if ((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));
9d1c15ef 37 return 1;
c03fae8a 38 }
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39if ((cp = string_printing(buf)) != buf)
40 {
41 Ustrncpy(buf, cp, buflen);
42 if (buf[buflen-1])
43 fail = 1;
44 }
45store_reset(reset_point);
46return fail;
47}
48
49int
50tls_import_cert(const uschar * buf, void ** cert)
51{
52void * reset_point = store_get(0);
53gnutls_datum_t datum;
152e7604 54gnutls_x509_crt_t crt = *(gnutls_x509_crt_t *)cert;
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55int fail = 0;
56
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57if (crt)
58 gnutls_x509_crt_deinit(crt);
59else
60 gnutls_global_init();
61
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62gnutls_x509_crt_init(&crt);
63
64datum.data = string_unprinting(US buf);
65datum.size = Ustrlen(datum.data);
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66if ((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));
9d1c15ef 70 fail = 1;
c03fae8a 71 }
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72else
73 *cert = (void *)crt;
74
75store_reset(reset_point);
76return fail;
77}
78
79void
790fbb71 80tls_free_cert(void ** cert)
9d1c15ef 81{
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82gnutls_x509_crt_t crt = *(gnutls_x509_crt_t *)cert;
83if (crt)
84 {
85 gnutls_x509_crt_deinit(crt);
86 gnutls_global_deinit();
87 *cert = NULL;
88 }
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89}
90
91/*****************************************************
92* Certificate field extraction routines
93*****************************************************/
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94
95/* First, some internal service functions */
96
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97static uschar *
98g_err(const char * tag, const char * from, int gnutls_err)
99{
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100expand_string_message = string_sprintf("%s: %s fail: %s\n",
101 from, tag, gnutls_strerror(gnutls_err));
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102return NULL;
103}
104
105
9d1c15ef 106static uschar *
25ba2544 107time_copy(time_t t, uschar * mod)
9d1c15ef 108{
25ba2544 109uschar * cp;
e9477a08 110size_t len = 32;
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111
112if (mod && Ustrcmp(mod, "int") == 0)
113 return string_sprintf("%u", (unsigned)t);
114
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115cp = store_get(len);
116if (timestamps_utc)
117 {
45500060 118 uschar * tz = to_tz(US"GMT0");
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119 len = strftime(CS cp, len, "%b %e %T %Y %Z", gmtime(&t));
120 restore_tz(tz);
121 }
122else
123 len = strftime(CS cp, len, "%b %e %T %Y %Z", localtime(&t));
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124return len > 0 ? cp : NULL;
125}
126
c03fae8a 127
9d1c15ef 128/**/
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129/* Now the extractors, called from expand.c
130Arguments:
131 cert The certificate
132 mod Optional modifiers for the operator
133
134Return:
135 Allocated string with extracted value
136*/
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137
138uschar *
9e4dddbd 139tls_cert_issuer(void * cert, uschar * mod)
9d1c15ef 140{
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141uschar * cp = NULL;
142int ret;
143size_t siz = 0;
144
76075bb5 145if ((ret = gnutls_x509_crt_get_issuer_dn(cert, CS cp, &siz))
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146 != GNUTLS_E_SHORT_MEMORY_BUFFER)
147 return g_err("gi0", __FUNCTION__, ret);
148
149cp = store_get(siz);
76075bb5 150if ((ret = gnutls_x509_crt_get_issuer_dn(cert, CS cp, &siz)) < 0)
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151 return g_err("gi1", __FUNCTION__, ret);
152
153return mod ? tls_field_from_dn(cp, mod) : cp;
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154}
155
156uschar *
9e4dddbd 157tls_cert_not_after(void * cert, uschar * mod)
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158{
159return time_copy(
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160 gnutls_x509_crt_get_expiration_time((gnutls_x509_crt_t)cert),
161 mod);
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162}
163
164uschar *
9e4dddbd 165tls_cert_not_before(void * cert, uschar * mod)
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166{
167return time_copy(
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168 gnutls_x509_crt_get_activation_time((gnutls_x509_crt_t)cert),
169 mod);
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170}
171
172uschar *
9e4dddbd 173tls_cert_serial_number(void * cert, uschar * mod)
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174{
175uschar bin[50], txt[150];
176size_t sz = sizeof(bin);
177uschar * sp;
178uschar * dp;
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179int ret;
180
181if ((ret = gnutls_x509_crt_get_serial((gnutls_x509_crt_t)cert,
182 bin, &sz)))
183 return g_err("gs0", __FUNCTION__, ret);
9d1c15ef 184
9d1c15ef 185for(dp = txt, sp = bin; sz; dp += 2, sp++, sz--)
76075bb5 186 sprintf(CS dp, "%.2x", *sp);
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187for(sp = txt; sp[0]=='0' && sp[1]; ) sp++; /* leading zeroes */
188return string_copy(sp);
189}
190
191uschar *
9e4dddbd 192tls_cert_signature(void * cert, uschar * mod)
9d1c15ef 193{
69cbeaec 194uschar * cp1 = NULL;
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195uschar * cp2;
196uschar * cp3;
197size_t len = 0;
198int ret;
199
76075bb5 200if ((ret = gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, CS cp1, &len))
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201 != GNUTLS_E_SHORT_MEMORY_BUFFER)
202 return g_err("gs0", __FUNCTION__, ret);
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203
204cp1 = store_get(len*4+1);
76075bb5 205if (gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, CS cp1, &len) != 0)
812a6045 206 return g_err("gs1", __FUNCTION__, ret);
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207
208for(cp3 = cp2 = cp1+len; cp1 < cp2; cp3 += 3, cp1++)
76075bb5 209 sprintf(CS cp3, "%.2x ", *cp1);
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210cp3[-1]= '\0';
211
212return cp2;
213}
214
215uschar *
9e4dddbd 216tls_cert_signature_algorithm(void * cert, uschar * mod)
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217{
218gnutls_sign_algorithm_t algo =
219 gnutls_x509_crt_get_signature_algorithm((gnutls_x509_crt_t)cert);
76075bb5 220return algo < 0 ? NULL : string_copy(US gnutls_sign_get_name(algo));
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221}
222
223uschar *
9e4dddbd 224tls_cert_subject(void * cert, uschar * mod)
9d1c15ef 225{
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226uschar * cp = NULL;
227int ret;
228size_t siz = 0;
229
76075bb5 230if ((ret = gnutls_x509_crt_get_dn(cert, CS cp, &siz))
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231 != GNUTLS_E_SHORT_MEMORY_BUFFER)
232 return g_err("gs0", __FUNCTION__, ret);
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233
234cp = store_get(siz);
76075bb5 235if ((ret = gnutls_x509_crt_get_dn(cert, CS cp, &siz)) < 0)
812a6045 236 return g_err("gs1", __FUNCTION__, ret);
8a6eec04 237
812a6045 238return mod ? tls_field_from_dn(cp, mod) : cp;
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239}
240
241uschar *
9e4dddbd 242tls_cert_version(void * cert, uschar * mod)
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243{
244return string_sprintf("%d", gnutls_x509_crt_get_version(cert));
245}
246
247uschar *
248tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
249{
250uschar * cp1 = NULL;
251uschar * cp2;
252uschar * cp3;
253size_t siz = 0;
254unsigned int crit;
255int ret;
256
257ret = gnutls_x509_crt_get_extension_by_oid ((gnutls_x509_crt_t)cert,
76075bb5 258 oid, idx, CS cp1, &siz, &crit);
9d1c15ef 259if (ret != GNUTLS_E_SHORT_MEMORY_BUFFER)
8a6eec04 260 return g_err("ge0", __FUNCTION__, ret);
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261
262cp1 = store_get(siz*4 + 1);
263
264ret = gnutls_x509_crt_get_extension_by_oid ((gnutls_x509_crt_t)cert,
76075bb5 265 oid, idx, CS cp1, &siz, &crit);
9d1c15ef 266if (ret < 0)
8a6eec04 267 return g_err("ge1", __FUNCTION__, ret);
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268
269/* binary data, DER encoded */
270
271/* just dump for now */
272for(cp3 = cp2 = cp1+siz; cp1 < cp2; cp3 += 3, cp1++)
76075bb5 273 sprintf(CS cp3, "%.2x ", *cp1);
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274cp3[-1]= '\0';
275
276return cp2;
277}
278
279uschar *
9e4dddbd 280tls_cert_subject_altname(void * cert, uschar * mod)
9d1c15ef 281{
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282uschar * list = NULL;
283int index;
284size_t siz;
9d1c15ef 285int ret;
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286uschar sep = '\n';
287uschar * tag = US"";
288uschar * ele;
289int match = -1;
9d1c15ef 290
9e4dddbd 291while (mod)
9d1c15ef 292 {
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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++ != ',')
9d1c15ef 300 break;
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301 }
302
9e4dddbd 303for(index = 0;; index++)
9d1c15ef 304 {
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305 siz = 0;
306 switch(ret = gnutls_x509_crt_get_subject_alt_name(
e51c7be2 307 (gnutls_x509_crt_t)cert, index, NULL, &siz, NULL))
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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:
8a6eec04 316 return g_err("gs0", __FUNCTION__, ret);
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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)
8a6eec04 322 return g_err("gs1", __FUNCTION__, ret);
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323 ele[siz] = '\0';
324
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325 if ( match != -1 && match != ret /* wrong type of SAN */
326 || Ustrlen(ele) != siz) /* contains a NUL */
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327 continue;
328 switch (ret)
329 {
330 case GNUTLS_SAN_DNSNAME: tag = US"DNS"; break;
94431adb 331 case GNUTLS_SAN_URI: tag = US"URI"; break;
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332 case GNUTLS_SAN_RFC822NAME: tag = US"MAIL"; break;
333 default: continue; /* ignore unrecognised types */
334 }
94431adb 335 list = string_append_listele(list, sep,
9e4dddbd 336 match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
9d1c15ef 337 }
9e4dddbd 338/*NOTREACHED*/
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339}
340
341uschar *
9e4dddbd 342tls_cert_ocsp_uri(void * cert, uschar * mod)
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343{
344#if GNUTLS_VERSION_NUMBER >= 0x030000
345gnutls_datum_t uri;
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346int ret;
347uschar sep = '\n';
348int index;
349uschar * list = NULL;
350
351if (mod)
352 if (*mod == '>' && *++mod) sep = *mod++;
9d1c15ef 353
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354for(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);
9d1c15ef 358
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359 if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
360 return list;
361 if (ret < 0)
8a6eec04 362 return g_err("gai", __FUNCTION__, ret);
9d1c15ef 363
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364 list = string_append_listele(list, sep,
365 string_copyn(uri.data, uri.size));
366 }
367/*NOTREACHED*/
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368
369#else
370
94431adb 371expand_string_message =
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372 string_sprintf("%s: OCSP support with GnuTLS requires version 3.0.0\n",
373 __FUNCTION__);
374return NULL;
375
376#endif
377}
378
379uschar *
9e4dddbd 380tls_cert_crl_uri(void * cert, uschar * mod)
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381{
382int ret;
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383size_t siz;
384uschar sep = '\n';
385int index;
386uschar * list = NULL;
387uschar * ele;
388
389if (mod)
390 if (*mod == '>' && *++mod) sep = *mod++;
9d1c15ef 391
9e4dddbd 392for(index = 0;; index++)
9d1c15ef 393 {
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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:
8a6eec04 403 return g_err("gc0", __FUNCTION__, ret);
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404 }
405
406 ele = store_get(siz+1);
407 if ((ret = gnutls_x509_crt_get_crl_dist_points(
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408 (gnutls_x509_crt_t)cert, index, ele, &siz, NULL, NULL)) < 0)
409 return g_err("gc1", __FUNCTION__, ret);
410
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411 ele[siz] = '\0';
412 list = string_append_listele(list, sep, ele);
9d1c15ef 413 }
9e4dddbd 414/*NOTREACHED*/
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415}
416
417
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418/*****************************************************
419* Certificate operator routines
420*****************************************************/
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421uschar *
422tls_cert_der_b64(void * cert)
423{
424size_t len = 0;
425uschar * cp = NULL;
426int fail;
427
428if ( (fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
429 GNUTLS_X509_FMT_DER, cp, &len)) != GNUTLS_E_SHORT_MEMORY_BUFFER
430 || !(cp = store_get((int)len))
431 || (fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
432 GNUTLS_X509_FMT_DER, cp, &len))
433 )
434 {
435 log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
436 gnutls_strerror(fail));
437 return NULL;
438 }
439return b64encode(cp, (int)len);
440}
441
442
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443static uschar *
444fingerprint(gnutls_x509_crt_t cert, gnutls_digest_algorithm_t algo)
445{
446int ret;
447size_t siz = 0;
448uschar * cp;
449uschar * cp2;
450uschar * cp3;
451
452if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, NULL, &siz))
453 != GNUTLS_E_SHORT_MEMORY_BUFFER)
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454 return g_err("gf0", __FUNCTION__, ret);
455
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456cp = store_get(siz*3+1);
457if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, cp, &siz)) < 0)
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458 return g_err("gf1", __FUNCTION__, ret);
459
6a8a60e0 460for (cp3 = cp2 = cp+siz; cp < cp2; cp++, cp3+=2)
76075bb5 461 sprintf(CS cp3, "%02X",*cp);
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462return cp2;
463}
464
465
466uschar *
467tls_cert_fprt_md5(void * cert)
468{
469return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_MD5);
470}
471
472uschar *
473tls_cert_fprt_sha1(void * cert)
474{
475return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_SHA1);
476}
477
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478uschar *
479tls_cert_fprt_sha256(void * cert)
480{
481return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_SHA256);
482}
483
6a8a60e0 484
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485/* vi: aw ai sw=2
486*/
487/* End of tlscert-gnu.c */