Import Debian changes 4.92-8+deb10u3
[hcoop/debian/exim4.git] / src / tlscert-gnu.c
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
2ea97746 5/* Copyright (c) Jeremy Harris 2014 - 2018 */
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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);
29int fail;
2ea97746 30const uschar * cp;
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31
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));
37 return 1;
38 }
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;
2ea97746 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);
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));
70 fail = 1;
71 }
72else
73 *cert = (void *)crt;
74
75store_reset(reset_point);
76return fail;
77}
78
79void
2ea97746 80tls_free_cert(void ** cert)
420a0d19 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*****************************************************/
94
95/* First, some internal service functions */
96
97static uschar *
98g_err(const char * tag, const char * from, int gnutls_err)
99{
100expand_string_message = string_sprintf("%s: %s fail: %s\n",
101 from, tag, gnutls_strerror(gnutls_err));
102return NULL;
103}
104
105
106static uschar *
107time_copy(time_t t, uschar * mod)
108{
109uschar * cp;
2ea97746 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 (f.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 }
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
127
128/**/
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*/
137
138uschar *
139tls_cert_issuer(void * cert, uschar * mod)
140{
141uschar * cp = NULL;
142int ret;
143size_t siz = 0;
144
2ea97746 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);
2ea97746 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;
154}
155
156uschar *
157tls_cert_not_after(void * cert, uschar * mod)
158{
159return time_copy(
160 gnutls_x509_crt_get_expiration_time((gnutls_x509_crt_t)cert),
161 mod);
162}
163
164uschar *
165tls_cert_not_before(void * cert, uschar * mod)
166{
167return time_copy(
168 gnutls_x509_crt_get_activation_time((gnutls_x509_crt_t)cert),
169 mod);
170}
171
172uschar *
173tls_cert_serial_number(void * cert, uschar * mod)
174{
175uschar bin[50], txt[150];
176size_t sz = sizeof(bin);
177uschar * sp;
178uschar * dp;
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);
184
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185for(dp = txt, sp = bin; sz; sz--)
186 dp += 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 *
192tls_cert_signature(void * cert, uschar * mod)
193{
2ea97746 194uschar * cp1 = NULL;
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195uschar * cp2;
196uschar * cp3;
197size_t len = 0;
198int ret;
199
2ea97746 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);
203
204cp1 = store_get(len*4+1);
2ea97746 205if (gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, CS cp1, &len) != 0)
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206 return g_err("gs1", __FUNCTION__, ret);
207
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208for(cp3 = cp2 = cp1+len; cp1 < cp2; cp1++)
209 cp3 += sprintf(CS cp3, "%.2x ", *cp1);
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210cp3[-1]= '\0';
211
212return cp2;
213}
214
215uschar *
216tls_cert_signature_algorithm(void * cert, uschar * mod)
217{
218gnutls_sign_algorithm_t algo =
219 gnutls_x509_crt_get_signature_algorithm((gnutls_x509_crt_t)cert);
2ea97746 220return algo < 0 ? NULL : string_copy(US gnutls_sign_get_name(algo));
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221}
222
223uschar *
224tls_cert_subject(void * cert, uschar * mod)
225{
226uschar * cp = NULL;
227int ret;
228size_t siz = 0;
229
2ea97746 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);
233
234cp = store_get(siz);
2ea97746 235if ((ret = gnutls_x509_crt_get_dn(cert, CS cp, &siz)) < 0)
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236 return g_err("gs1", __FUNCTION__, ret);
237
238return mod ? tls_field_from_dn(cp, mod) : cp;
239}
240
241uschar *
242tls_cert_version(void * cert, uschar * mod)
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,
2ea97746 258 CS oid, idx, CS cp1, &siz, &crit);
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259if (ret != GNUTLS_E_SHORT_MEMORY_BUFFER)
260 return g_err("ge0", __FUNCTION__, ret);
261
262cp1 = store_get(siz*4 + 1);
263
264ret = gnutls_x509_crt_get_extension_by_oid ((gnutls_x509_crt_t)cert,
2ea97746 265 CS oid, idx, CS cp1, &siz, &crit);
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266if (ret < 0)
267 return g_err("ge1", __FUNCTION__, ret);
268
269/* binary data, DER encoded */
270
271/* just dump for now */
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272for(cp3 = cp2 = cp1+siz; cp1 < cp2; cp1++)
273 cp3 += sprintf(CS cp3, "%.2x ", *cp1);
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274cp3[-1]= '\0';
275
276return cp2;
277}
278
279uschar *
280tls_cert_subject_altname(void * cert, uschar * mod)
281{
2ea97746 282gstring * list = NULL;
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283int index;
284size_t siz;
285int ret;
286uschar sep = '\n';
287uschar * tag = US"";
288uschar * ele;
289int match = -1;
290
291while (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
303for(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:
2ea97746 310 return string_from_gstring(list); /* no more elements; normal exit */
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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;
2ea97746 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 }
2ea97746 335 list = string_append_listele(list, sep,
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336 match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
337 }
338/*NOTREACHED*/
339}
340
341uschar *
342tls_cert_ocsp_uri(void * cert, uschar * mod)
343{
344#if GNUTLS_VERSION_NUMBER >= 0x030000
345gnutls_datum_t uri;
346int ret;
347uschar sep = '\n';
348int index;
2ea97746 349gstring * list = NULL;
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350
351if (mod)
352 if (*mod == '>' && *++mod) sep = *mod++;
353
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);
358
359 if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
2ea97746 360 return string_from_gstring(list);
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361 if (ret < 0)
362 return g_err("gai", __FUNCTION__, ret);
363
2ea97746 364 list = string_append_listele_n(list, sep, uri.data, uri.size);
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365 }
366/*NOTREACHED*/
367
368#else
369
2ea97746 370expand_string_message =
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371 string_sprintf("%s: OCSP support with GnuTLS requires version 3.0.0\n",
372 __FUNCTION__);
373return NULL;
374
375#endif
376}
377
378uschar *
379tls_cert_crl_uri(void * cert, uschar * mod)
380{
381int ret;
382size_t siz;
383uschar sep = '\n';
384int index;
2ea97746 385gstring * list = NULL;
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386uschar * ele;
387
388if (mod)
389 if (*mod == '>' && *++mod) sep = *mod++;
390
391for(index = 0;; index++)
392 {
393 siz = 0;
394 switch(ret = gnutls_x509_crt_get_crl_dist_points(
395 (gnutls_x509_crt_t)cert, index, NULL, &siz, NULL, NULL))
396 {
397 case GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE:
2ea97746 398 return string_from_gstring(list);
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399 case GNUTLS_E_SHORT_MEMORY_BUFFER:
400 break;
401 default:
402 return g_err("gc0", __FUNCTION__, ret);
403 }
404
2ea97746 405 ele = store_get(siz);
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406 if ((ret = gnutls_x509_crt_get_crl_dist_points(
407 (gnutls_x509_crt_t)cert, index, ele, &siz, NULL, NULL)) < 0)
408 return g_err("gc1", __FUNCTION__, ret);
409
2ea97746 410 list = string_append_listele_n(list, sep, ele, siz);
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411 }
412/*NOTREACHED*/
413}
414
415
416/*****************************************************
417* Certificate operator routines
418*****************************************************/
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419uschar *
420tls_cert_der_b64(void * cert)
421{
422size_t len = 0;
423uschar * cp = NULL;
424int fail;
425
426if ( (fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
427 GNUTLS_X509_FMT_DER, cp, &len)) != GNUTLS_E_SHORT_MEMORY_BUFFER
428 || !(cp = store_get((int)len))
429 || (fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
430 GNUTLS_X509_FMT_DER, cp, &len))
431 )
432 {
433 log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
434 gnutls_strerror(fail));
435 return NULL;
436 }
437return b64encode(cp, (int)len);
438}
439
440
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441static uschar *
442fingerprint(gnutls_x509_crt_t cert, gnutls_digest_algorithm_t algo)
443{
444int ret;
445size_t siz = 0;
446uschar * cp;
447uschar * cp2;
448uschar * cp3;
449
450if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, NULL, &siz))
451 != GNUTLS_E_SHORT_MEMORY_BUFFER)
452 return g_err("gf0", __FUNCTION__, ret);
453
454cp = store_get(siz*3+1);
455if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, cp, &siz)) < 0)
456 return g_err("gf1", __FUNCTION__, ret);
457
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458for (cp3 = cp2 = cp+siz; cp < cp2; cp++)
459 cp3 += sprintf(CS cp3, "%02X", *cp);
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460return cp2;
461}
462
463
464uschar *
465tls_cert_fprt_md5(void * cert)
466{
467return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_MD5);
468}
469
470uschar *
471tls_cert_fprt_sha1(void * cert)
472{
473return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_SHA1);
474}
475
476uschar *
477tls_cert_fprt_sha256(void * cert)
478{
479return fingerprint((gnutls_x509_crt_t)cert, GNUTLS_DIG_SHA256);
480}
481
482
483/* vi: aw ai sw=2
484*/
485/* End of tlscert-gnu.c */