938b0abb8a4123a62af6238ed9245f25b1cb4b00
[exim.git] / src / src / tlscert-openssl.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) Jeremy Harris 2014 - 2018 */
6
7 /* This module provides TLS (aka SSL) support for Exim using the OpenSSL
8 library. It is #included into the tls.c file when that library is used.
9 */
10
11
12 /* Heading stuff */
13
14 #include <openssl/lhash.h>
15 #include <openssl/ssl.h>
16 #include <openssl/err.h>
17 #include <openssl/rand.h>
18 #include <openssl/x509v3.h>
19
20 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
21 # define EXIM_HAVE_ASN1_MACROS
22 #endif
23
24 #if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
25 # define ASN1_STRING_get0_data ASN1_STRING_data
26 #endif
27
28 /*****************************************************
29 * Export/import a certificate, binary/printable
30 *****************************************************/
31 int
32 tls_export_cert(uschar * buf, size_t buflen, void * cert)
33 {
34 BIO * bp = BIO_new(BIO_s_mem());
35 int fail;
36
37 if ((fail = PEM_write_bio_X509(bp, (X509 *)cert) ? 0 : 1))
38 log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
39 ERR_error_string(ERR_get_error(), NULL));
40 else
41 {
42 char * cp = CS buf;
43 int n;
44 buflen -= 2;
45 for(;;)
46 {
47 if ((n = BIO_gets(bp, cp, (int)buflen)) <= 0) break;
48 cp += n+1;
49 buflen -= n+1;
50 cp[-2] = '\\'; cp[-1] = 'n'; /* newline->"\n" */
51 } /* compat with string_printing() */
52 *cp = '\0';
53 }
54
55 BIO_free(bp);
56 return fail;
57 }
58
59 int
60 tls_import_cert(const uschar * buf, void ** cert)
61 {
62 void * reset_point = store_get(0);
63 const uschar * cp = string_unprinting(US buf);
64 BIO * bp;
65 X509 * x = *(X509 **)cert;
66 int fail = 0;
67
68 if (x) X509_free(x);
69
70 bp = BIO_new_mem_buf(US cp, -1);
71 if (!(x = PEM_read_bio_X509(bp, NULL, 0, NULL)))
72 {
73 log_write(0, LOG_MAIN, "TLS error in certificate import: %s",
74 ERR_error_string(ERR_get_error(), NULL));
75 fail = 1;
76 }
77 else
78 *cert = (void *)x;
79 BIO_free(bp);
80 store_reset(reset_point);
81 return fail;
82 }
83
84 void
85 tls_free_cert(void ** cert)
86 {
87 X509 * x = *(X509 **)cert;
88 if (x)
89 {
90 X509_free(x);
91 *cert = NULL;
92 }
93 }
94
95
96 /*****************************************************
97 * Certificate field extraction routines
98 *****************************************************/
99
100 /* First, some internal service functions */
101
102 static uschar *
103 badalloc(void)
104 {
105 expand_string_message = US"allocation failure";
106 return NULL;
107 }
108
109 static uschar *
110 bio_string_copy(BIO * bp, int len)
111 {
112 uschar * cp = US"";
113 len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0;
114 cp = string_copyn(cp, len);
115 BIO_free(bp);
116 return cp;
117 }
118
119 static uschar *
120 asn1_time_copy(const ASN1_TIME * asntime, uschar * mod)
121 {
122 uschar * s = NULL;
123 BIO * bp = BIO_new(BIO_s_mem());
124 int len;
125
126 if (!bp)
127 return badalloc();
128 len = ASN1_TIME_print(bp, asntime);
129 len = len > 0 ? (int) BIO_get_mem_data(bp, CSS &s) : 0;
130
131 if (mod && Ustrcmp(mod, "raw") == 0) /* native ASN */
132 s = string_copyn(s, len);
133 else
134 {
135 struct tm tm;
136 struct tm * tm_p = &tm;
137 BOOL mod_tz = TRUE;
138 uschar * tz = to_tz(US"GMT0"); /* need to call strptime with baseline TZ */
139
140 /* Parse OpenSSL ASN1_TIME_print output. A shame there seems to
141 be no other interface for the times.
142 */
143
144 /*XXX %Z might be glibc-specific? Solaris has it, at least*/
145 /*XXX should we switch to POSIX locale for this? */
146 tm.tm_isdst = 0;
147 if (!len || !strptime(CCS s, "%b %e %T %Y %Z", &tm))
148 expand_string_message = US"failed time conversion";
149
150 else
151 {
152 time_t t = mktime(&tm); /* make the tm self-consistent */
153
154 if (mod && Ustrcmp(mod, "int") == 0) /* seconds since epoch */
155 s = string_sprintf(TIME_T_FMT, t);
156
157 else
158 {
159 if (!f.timestamps_utc) /* decoded string in local TZ */
160 { /* shift to local TZ */
161 restore_tz(tz);
162 mod_tz = FALSE;
163 tm_p = localtime(&t);
164 }
165 /* "utc" is default, and rfc5280 says cert times should be Zulu */
166
167 /* convert to string in our format */
168 len = 32;
169 s = store_get(len);
170 strftime(CS s, (size_t)len, "%b %e %T %Y %z", tm_p);
171 }
172 }
173
174 if (mod_tz)
175 restore_tz(tz);
176 }
177 BIO_free(bp);
178 return s;
179 }
180
181 static uschar *
182 x509_name_copy(X509_NAME * name)
183 {
184 BIO * bp = BIO_new(BIO_s_mem());
185 int len_good;
186
187 if (!bp) return badalloc();
188
189 len_good =
190 X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0
191 ? 1 : 0;
192 return bio_string_copy(bp, len_good);
193 }
194
195 /**/
196 /* Now the extractors, called from expand.c
197 Arguments:
198 cert The certificate
199 mod Optional modifiers for the operator
200
201 Return:
202 Allocated string with extracted value
203 */
204
205 uschar *
206 tls_cert_issuer(void * cert, uschar * mod)
207 {
208 uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert));
209 return mod ? tls_field_from_dn(cp, mod) : cp;
210 }
211
212 uschar *
213 tls_cert_not_before(void * cert, uschar * mod)
214 {
215 return asn1_time_copy(X509_get_notBefore((X509 *)cert), mod);
216 }
217
218 uschar *
219 tls_cert_not_after(void * cert, uschar * mod)
220 {
221 return asn1_time_copy(X509_get_notAfter((X509 *)cert), mod);
222 }
223
224 uschar *
225 tls_cert_serial_number(void * cert, uschar * mod)
226 {
227 uschar txt[256];
228 BIO * bp = BIO_new(BIO_s_mem());
229 int len;
230
231 if (!bp) return badalloc();
232
233 len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
234 if (len < sizeof(txt))
235 BIO_read(bp, txt, len);
236 else
237 len = 0;
238 BIO_free(bp);
239 return string_copynlc(txt, len); /* lowercase */
240 }
241
242 uschar *
243 tls_cert_signature(void * cert, uschar * mod)
244 {
245 uschar * cp = NULL;
246 BIO * bp = BIO_new(BIO_s_mem());
247
248 if (!bp) return badalloc();
249
250 if (X509_print_ex(bp, (X509 *)cert, 0,
251 X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
252 X509_FLAG_NO_SIGNAME | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
253 X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
254 /* X509_FLAG_NO_SIGDUMP is the missing one */
255 X509_FLAG_NO_AUX) == 1)
256 {
257 long len = BIO_get_mem_data(bp, &cp);
258
259 /* Strip leading "Signature Algorithm" line */
260 while (*cp && *cp != '\n') { cp++; len--; }
261
262 cp = string_copyn(cp+1, len-1);
263 }
264 BIO_free(bp);
265 return cp;
266 }
267
268 uschar *
269 tls_cert_signature_algorithm(void * cert, uschar * mod)
270 {
271 uschar * cp = NULL;
272 BIO * bp = BIO_new(BIO_s_mem());
273
274 if (!bp) return badalloc();
275
276 if (X509_print_ex(bp, (X509 *)cert, 0,
277 X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
278 /* X509_FLAG_NO_SIGNAME is the missing one */
279 X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
280 X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
281 X509_FLAG_NO_SIGDUMP | X509_FLAG_NO_AUX) == 1)
282 {
283 long len = BIO_get_mem_data(bp, &cp);
284
285 /* Strip leading " Signature Algorithm: " and trailing newline */
286 while (*cp && *cp != ':') { cp++; len--; }
287 do { cp++; len--; } while (*cp && *cp == ' ');
288 if (cp[len-1] == '\n') len--;
289
290 cp = string_copyn(cp, len);
291 }
292 BIO_free(bp);
293 return cp;
294 }
295
296 uschar *
297 tls_cert_subject(void * cert, uschar * mod)
298 {
299 uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert));
300 return mod ? tls_field_from_dn(cp, mod) : cp;
301 }
302
303 uschar *
304 tls_cert_version(void * cert, uschar * mod)
305 {
306 return string_sprintf("%ld", X509_get_version((X509 *)cert));
307 }
308
309 uschar *
310 tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
311 {
312 int nid = OBJ_create(CS oid, "", "");
313 int nidx = X509_get_ext_by_NID((X509 *)cert, nid, idx);
314 X509_EXTENSION * ex = X509_get_ext((X509 *)cert, nidx);
315 ASN1_OCTET_STRING * adata = X509_EXTENSION_get_data(ex);
316 BIO * bp = BIO_new(BIO_s_mem());
317 long len;
318 uschar * cp1;
319 uschar * cp2;
320 uschar * cp3;
321
322 if (!bp) return badalloc();
323
324 #ifdef EXIM_HAVE_ASN1_MACROS
325 ASN1_STRING_print(bp, adata);
326 #else
327 M_ASN1_OCTET_STRING_print(bp, adata);
328 #endif
329
330 /* binary data, DER encoded */
331 /* just dump for now */
332 len = BIO_get_mem_data(bp, &cp1);
333 cp3 = cp2 = store_get(len*3+1);
334
335 while(len)
336 {
337 cp2 += sprintf(CS cp2, "%.2x ", *cp1++);
338 len--;
339 }
340 cp2[-1] = '\0';
341
342 return cp3;
343 }
344
345 uschar *
346 tls_cert_subject_altname(void * cert, uschar * mod)
347 {
348 gstring * list = NULL;
349 STACK_OF(GENERAL_NAME) * san = (STACK_OF(GENERAL_NAME) *)
350 X509_get_ext_d2i((X509 *)cert, NID_subject_alt_name, NULL, NULL);
351 uschar osep = '\n';
352 uschar * tag = US"";
353 uschar * ele;
354 int match = -1;
355 int len;
356
357 if (!san) return NULL;
358
359 while (mod && *mod)
360 {
361 if (*mod == '>' && *++mod) osep = *mod++;
362 else if (Ustrncmp(mod,"dns",3)==0) { match = GEN_DNS; mod += 3; }
363 else if (Ustrncmp(mod,"uri",3)==0) { match = GEN_URI; mod += 3; }
364 else if (Ustrncmp(mod,"mail",4)==0) { match = GEN_EMAIL; mod += 4; }
365 else mod++;
366
367 if (*mod == ',') mod++;
368 }
369
370 while (sk_GENERAL_NAME_num(san) > 0)
371 {
372 GENERAL_NAME * namePart = sk_GENERAL_NAME_pop(san);
373 if (match != -1 && match != namePart->type)
374 continue;
375 switch (namePart->type)
376 {
377 case GEN_DNS:
378 tag = US"DNS";
379 ele = US ASN1_STRING_get0_data(namePart->d.dNSName);
380 len = ASN1_STRING_length(namePart->d.dNSName);
381 break;
382 case GEN_URI:
383 tag = US"URI";
384 ele = US ASN1_STRING_get0_data(namePart->d.uniformResourceIdentifier);
385 len = ASN1_STRING_length(namePart->d.uniformResourceIdentifier);
386 break;
387 case GEN_EMAIL:
388 tag = US"MAIL";
389 ele = US ASN1_STRING_get0_data(namePart->d.rfc822Name);
390 len = ASN1_STRING_length(namePart->d.rfc822Name);
391 break;
392 default:
393 continue; /* ignore unrecognised types */
394 }
395 if (ele[len]) /* not nul-terminated */
396 ele = string_copyn(ele, len);
397
398 if (Ustrlen(ele) == len) /* ignore any with embedded nul */
399 list = string_append_listele(list, osep,
400 match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
401 }
402
403 sk_GENERAL_NAME_free(san);
404 return string_from_gstring(list);
405 }
406
407 uschar *
408 tls_cert_ocsp_uri(void * cert, uschar * mod)
409 {
410 STACK_OF(ACCESS_DESCRIPTION) * ads = (STACK_OF(ACCESS_DESCRIPTION) *)
411 X509_get_ext_d2i((X509 *)cert, NID_info_access, NULL, NULL);
412 int adsnum = sk_ACCESS_DESCRIPTION_num(ads);
413 uschar sep = '\n';
414 gstring * list = NULL;
415
416 if (mod)
417 if (*mod == '>' && *++mod) sep = *mod++;
418
419 for (int i = 0; i < adsnum; i++)
420 {
421 ACCESS_DESCRIPTION * ad = sk_ACCESS_DESCRIPTION_value(ads, i);
422
423 if (ad && OBJ_obj2nid(ad->method) == NID_ad_OCSP)
424 list = string_append_listele_n(list, sep,
425 US ASN1_STRING_get0_data(ad->location->d.ia5),
426 ASN1_STRING_length(ad->location->d.ia5));
427 }
428 sk_ACCESS_DESCRIPTION_free(ads);
429 return string_from_gstring(list);
430 }
431
432 uschar *
433 tls_cert_crl_uri(void * cert, uschar * mod)
434 {
435 STACK_OF(DIST_POINT) * dps = (STACK_OF(DIST_POINT) *)
436 X509_get_ext_d2i((X509 *)cert, NID_crl_distribution_points,
437 NULL, NULL);
438 DIST_POINT * dp;
439 uschar sep = '\n';
440 gstring * list = NULL;
441
442 if (mod)
443 if (*mod == '>' && *++mod) sep = *mod++;
444
445 if (dps) for (int i = 0, dpsnum = sk_DIST_POINT_num(dps); i < dpsnum; i++)
446 if ((dp = sk_DIST_POINT_value(dps, i)))
447 {
448 STACK_OF(GENERAL_NAME) * names = dp->distpoint->name.fullname;
449 GENERAL_NAME * np;
450
451 for (int j = 0, nnum = sk_GENERAL_NAME_num(names); j < nnum; j++)
452 if ( (np = sk_GENERAL_NAME_value(names, j))
453 && np->type == GEN_URI
454 )
455 list = string_append_listele_n(list, sep,
456 US ASN1_STRING_get0_data(np->d.uniformResourceIdentifier),
457 ASN1_STRING_length(np->d.uniformResourceIdentifier));
458 }
459 sk_DIST_POINT_free(dps);
460 return string_from_gstring(list);
461 }
462
463
464
465 /*****************************************************
466 * Certificate operator routines
467 *****************************************************/
468 uschar *
469 tls_cert_der_b64(void * cert)
470 {
471 BIO * bp = BIO_new(BIO_s_mem());
472 uschar * cp = NULL;
473
474 if (!i2d_X509_bio(bp, (X509 *)cert))
475 log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
476 ERR_error_string(ERR_get_error(), NULL));
477 else
478 {
479 long len = BIO_get_mem_data(bp, &cp);
480 cp = b64encode(cp, (int)len);
481 }
482
483 BIO_free(bp);
484 return cp;
485 }
486
487
488 static uschar *
489 fingerprint(X509 * cert, const EVP_MD * fdig)
490 {
491 unsigned int n;
492 uschar md[EVP_MAX_MD_SIZE];
493 uschar * cp;
494
495 if (!X509_digest(cert,fdig,md,&n))
496 {
497 expand_string_message = US"tls_cert_fprt: out of mem\n";
498 return NULL;
499 }
500 cp = store_get(n*2+1);
501 for (int j = 0; j < (int)n; j++) sprintf(CS cp+2*j, "%02X", md[j]);
502 return(cp);
503 }
504
505 uschar *
506 tls_cert_fprt_md5(void * cert)
507 {
508 return fingerprint((X509 *)cert, EVP_md5());
509 }
510
511 uschar *
512 tls_cert_fprt_sha1(void * cert)
513 {
514 return fingerprint((X509 *)cert, EVP_sha1());
515 }
516
517 uschar *
518 tls_cert_fprt_sha256(void * cert)
519 {
520 return fingerprint((X509 *)cert, EVP_sha256());
521 }
522
523
524 /* vi: aw ai sw=2
525 */
526 /* End of tlscert-openssl.c */