Always check return from tls_export_cert()
[exim.git] / src / src / tlscert-openssl.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) Jeremy Harris 2014 - 2019 */
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 #ifdef LIBRESSL_VERSION_NUMBER /* LibreSSL */
21 # if LIBRESSL_VERSION_NUMBER >= 0x2090000fL
22 # define EXIM_HAVE_ASN1_MACROS
23 # endif
24 #else /* OpenSSL */
25 # if OPENSSL_VERSION_NUMBER >= 0x10100000L
26 # define EXIM_HAVE_ASN1_MACROS
27 # endif
28 #endif
29
30 #if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
31 # define ASN1_STRING_get0_data ASN1_STRING_data
32 #endif
33
34 /*****************************************************
35 * Export/import a certificate, binary/printable
36 *****************************************************/
37 BOOL
38 tls_export_cert(uschar * buf, size_t buflen, void * cert)
39 {
40 BIO * bp = BIO_new(BIO_s_mem());
41 BOOL fail;
42
43 if ((fail = PEM_write_bio_X509(bp, (X509 *)cert) ? 0 : 1))
44 log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
45 ERR_error_string(ERR_get_error(), NULL));
46 else
47 {
48 char * cp = CS buf;
49 int n;
50 buflen -= 2;
51 for(;;)
52 {
53 if ((n = BIO_gets(bp, cp, (int)buflen)) <= 0) break;
54 cp += n+1;
55 buflen -= n+1;
56 cp[-2] = '\\'; cp[-1] = 'n'; /* newline->"\n" */
57 } /* compat with string_printing() */
58 *cp = '\0';
59 }
60
61 BIO_free(bp);
62 return !fail;
63 }
64
65 int
66 tls_import_cert(const uschar * buf, void ** cert)
67 {
68 rmark reset_point = store_mark();
69 const uschar * cp = string_unprinting(US buf);
70 BIO * bp;
71 X509 * x = *(X509 **)cert;
72 int fail = 0;
73
74 if (x) X509_free(x);
75
76 bp = BIO_new_mem_buf(US cp, -1);
77 if (!(x = PEM_read_bio_X509(bp, NULL, 0, NULL)))
78 {
79 log_write(0, LOG_MAIN, "TLS error in certificate import: %s",
80 ERR_error_string(ERR_get_error(), NULL));
81 fail = 1;
82 }
83 else
84 *cert = (void *)x;
85 BIO_free(bp);
86 store_reset(reset_point);
87 return fail;
88 }
89
90 void
91 tls_free_cert(void ** cert)
92 {
93 X509 * x = *(X509 **)cert;
94 if (x)
95 {
96 X509_free(x);
97 *cert = NULL;
98 }
99 }
100
101
102 /*****************************************************
103 * Certificate field extraction routines
104 *****************************************************/
105
106 /* First, some internal service functions */
107
108 static uschar *
109 badalloc(void)
110 {
111 expand_string_message = US"allocation failure";
112 return NULL;
113 }
114
115 static uschar *
116 bio_string_copy(BIO * bp, int len)
117 {
118 uschar * cp = US"";
119 len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0;
120 cp = string_copyn(cp, len);
121 BIO_free(bp);
122 return cp;
123 }
124
125 static uschar *
126 asn1_time_copy(const ASN1_TIME * asntime, uschar * mod)
127 {
128 uschar * s = NULL;
129 BIO * bp = BIO_new(BIO_s_mem());
130 int len;
131
132 if (!bp)
133 return badalloc();
134 len = ASN1_TIME_print(bp, asntime);
135 len = len > 0 ? (int) BIO_get_mem_data(bp, CSS &s) : 0;
136
137 if (mod && Ustrcmp(mod, "raw") == 0) /* native ASN */
138 s = string_copyn(s, len);
139 else
140 {
141 struct tm tm;
142 struct tm * tm_p = &tm;
143 BOOL mod_tz = TRUE;
144 uschar * tz = to_tz(US"GMT0"); /* need to call strptime with baseline TZ */
145
146 /* Parse OpenSSL ASN1_TIME_print output. A shame there seems to
147 be no other interface for the times.
148 */
149
150 /*XXX %Z might be glibc-specific? Solaris has it, at least*/
151 /*XXX should we switch to POSIX locale for this? */
152 tm.tm_isdst = 0;
153 if (!len || !strptime(CCS s, "%b %e %T %Y %Z", &tm))
154 expand_string_message = US"failed time conversion";
155
156 else
157 {
158 time_t t = mktime(&tm); /* make the tm self-consistent */
159
160 if (mod && Ustrcmp(mod, "int") == 0) /* seconds since epoch */
161 s = string_sprintf(TIME_T_FMT, t);
162
163 else
164 {
165 if (!f.timestamps_utc) /* decoded string in local TZ */
166 { /* shift to local TZ */
167 restore_tz(tz);
168 mod_tz = FALSE;
169 tm_p = localtime(&t);
170 }
171 /* "utc" is default, and rfc5280 says cert times should be Zulu */
172
173 /* convert to string in our format */
174 len = 32;
175 s = store_get(len, FALSE);
176 strftime(CS s, (size_t)len, "%b %e %T %Y %z", tm_p);
177 }
178 }
179
180 if (mod_tz)
181 restore_tz(tz);
182 }
183 BIO_free(bp);
184 return s;
185 }
186
187 static uschar *
188 x509_name_copy(X509_NAME * name)
189 {
190 BIO * bp = BIO_new(BIO_s_mem());
191 int len_good;
192
193 if (!bp) return badalloc();
194
195 len_good =
196 X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0
197 ? 1 : 0;
198 return bio_string_copy(bp, len_good);
199 }
200
201 /**/
202 /* Now the extractors, called from expand.c
203 Arguments:
204 cert The certificate
205 mod Optional modifiers for the operator
206
207 Return:
208 Allocated string with extracted value
209 */
210
211 uschar *
212 tls_cert_issuer(void * cert, uschar * mod)
213 {
214 uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert));
215 return mod ? tls_field_from_dn(cp, mod) : cp;
216 }
217
218 uschar *
219 tls_cert_not_before(void * cert, uschar * mod)
220 {
221 return asn1_time_copy(X509_get_notBefore((X509 *)cert), mod);
222 }
223
224 uschar *
225 tls_cert_not_after(void * cert, uschar * mod)
226 {
227 return asn1_time_copy(X509_get_notAfter((X509 *)cert), mod);
228 }
229
230 uschar *
231 tls_cert_serial_number(void * cert, uschar * mod)
232 {
233 uschar txt[256];
234 BIO * bp = BIO_new(BIO_s_mem());
235 int len;
236
237 if (!bp) return badalloc();
238
239 len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
240 if (len < sizeof(txt))
241 BIO_read(bp, txt, len);
242 else
243 len = 0;
244 BIO_free(bp);
245 return string_copynlc(txt, len); /* lowercase */
246 }
247
248 uschar *
249 tls_cert_signature(void * cert, uschar * mod)
250 {
251 uschar * cp = NULL;
252 BIO * bp = BIO_new(BIO_s_mem());
253
254 if (!bp) return badalloc();
255
256 if (X509_print_ex(bp, (X509 *)cert, 0,
257 X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
258 X509_FLAG_NO_SIGNAME | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
259 X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
260 /* X509_FLAG_NO_SIGDUMP is the missing one */
261 X509_FLAG_NO_AUX) == 1)
262 {
263 long len = BIO_get_mem_data(bp, &cp);
264
265 /* Strip leading "Signature Algorithm" line */
266 while (*cp && *cp != '\n') { cp++; len--; }
267
268 cp = string_copyn(cp+1, len-1);
269 }
270 BIO_free(bp);
271 return cp;
272 }
273
274 uschar *
275 tls_cert_signature_algorithm(void * cert, uschar * mod)
276 {
277 uschar * cp = NULL;
278 BIO * bp = BIO_new(BIO_s_mem());
279
280 if (!bp) return badalloc();
281
282 if (X509_print_ex(bp, (X509 *)cert, 0,
283 X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
284 /* X509_FLAG_NO_SIGNAME is the missing one */
285 X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
286 X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
287 X509_FLAG_NO_SIGDUMP | X509_FLAG_NO_AUX) == 1)
288 {
289 long len = BIO_get_mem_data(bp, &cp);
290
291 /* Strip leading " Signature Algorithm: " and trailing newline */
292 while (*cp && *cp != ':') { cp++; len--; }
293 do { cp++; len--; } while (*cp && *cp == ' ');
294 if (cp[len-1] == '\n') len--;
295
296 cp = string_copyn(cp, len);
297 }
298 BIO_free(bp);
299 return cp;
300 }
301
302 uschar *
303 tls_cert_subject(void * cert, uschar * mod)
304 {
305 uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert));
306 return mod ? tls_field_from_dn(cp, mod) : cp;
307 }
308
309 uschar *
310 tls_cert_version(void * cert, uschar * mod)
311 {
312 return string_sprintf("%ld", X509_get_version((X509 *)cert));
313 }
314
315 uschar *
316 tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
317 {
318 int nid = OBJ_create(CS oid, "", "");
319 int nidx = X509_get_ext_by_NID((X509 *)cert, nid, idx);
320 X509_EXTENSION * ex = X509_get_ext((X509 *)cert, nidx);
321 ASN1_OCTET_STRING * adata = X509_EXTENSION_get_data(ex);
322 BIO * bp = BIO_new(BIO_s_mem());
323 long len;
324 uschar * cp1;
325 uschar * cp2;
326 uschar * cp3;
327
328 if (!bp) return badalloc();
329
330 #ifdef EXIM_HAVE_ASN1_MACROS
331 ASN1_STRING_print(bp, adata);
332 #else
333 M_ASN1_OCTET_STRING_print(bp, adata);
334 #endif
335
336 /* binary data, DER encoded */
337 /* just dump for now */
338 len = BIO_get_mem_data(bp, &cp1);
339 cp3 = cp2 = store_get(len*3+1, TRUE);
340
341 while(len)
342 {
343 cp2 += sprintf(CS cp2, "%.2x ", *cp1++);
344 len--;
345 }
346 cp2[-1] = '\0';
347
348 return cp3;
349 }
350
351 uschar *
352 tls_cert_subject_altname(void * cert, uschar * mod)
353 {
354 gstring * list = NULL;
355 STACK_OF(GENERAL_NAME) * san = (STACK_OF(GENERAL_NAME) *)
356 X509_get_ext_d2i((X509 *)cert, NID_subject_alt_name, NULL, NULL);
357 uschar osep = '\n';
358 uschar * tag = US"";
359 uschar * ele;
360 int match = -1;
361 int len;
362
363 if (!san) return NULL;
364
365 while (mod && *mod)
366 {
367 if (*mod == '>' && *++mod) osep = *mod++;
368 else if (Ustrncmp(mod,"dns",3)==0) { match = GEN_DNS; mod += 3; }
369 else if (Ustrncmp(mod,"uri",3)==0) { match = GEN_URI; mod += 3; }
370 else if (Ustrncmp(mod,"mail",4)==0) { match = GEN_EMAIL; mod += 4; }
371 else mod++;
372
373 if (*mod == ',') mod++;
374 }
375
376 while (sk_GENERAL_NAME_num(san) > 0)
377 {
378 GENERAL_NAME * namePart = sk_GENERAL_NAME_pop(san);
379 if (match != -1 && match != namePart->type)
380 continue;
381 switch (namePart->type)
382 {
383 case GEN_DNS:
384 tag = US"DNS";
385 ele = US ASN1_STRING_get0_data(namePart->d.dNSName);
386 len = ASN1_STRING_length(namePart->d.dNSName);
387 break;
388 case GEN_URI:
389 tag = US"URI";
390 ele = US ASN1_STRING_get0_data(namePart->d.uniformResourceIdentifier);
391 len = ASN1_STRING_length(namePart->d.uniformResourceIdentifier);
392 break;
393 case GEN_EMAIL:
394 tag = US"MAIL";
395 ele = US ASN1_STRING_get0_data(namePart->d.rfc822Name);
396 len = ASN1_STRING_length(namePart->d.rfc822Name);
397 break;
398 default:
399 continue; /* ignore unrecognised types */
400 }
401 if (ele[len]) /* not nul-terminated */
402 ele = string_copyn(ele, len);
403
404 if (Ustrlen(ele) == len) /* ignore any with embedded nul */
405 list = string_append_listele(list, osep,
406 match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
407 }
408
409 sk_GENERAL_NAME_free(san);
410 return string_from_gstring(list);
411 }
412
413 uschar *
414 tls_cert_ocsp_uri(void * cert, uschar * mod)
415 {
416 STACK_OF(ACCESS_DESCRIPTION) * ads = (STACK_OF(ACCESS_DESCRIPTION) *)
417 X509_get_ext_d2i((X509 *)cert, NID_info_access, NULL, NULL);
418 int adsnum = sk_ACCESS_DESCRIPTION_num(ads);
419 uschar sep = '\n';
420 gstring * list = NULL;
421
422 if (mod)
423 if (*mod == '>' && *++mod) sep = *mod++;
424
425 for (int i = 0; i < adsnum; i++)
426 {
427 ACCESS_DESCRIPTION * ad = sk_ACCESS_DESCRIPTION_value(ads, i);
428
429 if (ad && OBJ_obj2nid(ad->method) == NID_ad_OCSP)
430 list = string_append_listele_n(list, sep,
431 US ASN1_STRING_get0_data(ad->location->d.ia5),
432 ASN1_STRING_length(ad->location->d.ia5));
433 }
434 sk_ACCESS_DESCRIPTION_free(ads);
435 return string_from_gstring(list);
436 }
437
438 uschar *
439 tls_cert_crl_uri(void * cert, uschar * mod)
440 {
441 STACK_OF(DIST_POINT) * dps = (STACK_OF(DIST_POINT) *)
442 X509_get_ext_d2i((X509 *)cert, NID_crl_distribution_points,
443 NULL, NULL);
444 DIST_POINT * dp;
445 uschar sep = '\n';
446 gstring * list = NULL;
447
448 if (mod)
449 if (*mod == '>' && *++mod) sep = *mod++;
450
451 if (dps) for (int i = 0, dpsnum = sk_DIST_POINT_num(dps); i < dpsnum; i++)
452 if ((dp = sk_DIST_POINT_value(dps, i)))
453 {
454 STACK_OF(GENERAL_NAME) * names = dp->distpoint->name.fullname;
455 GENERAL_NAME * np;
456
457 for (int j = 0, nnum = sk_GENERAL_NAME_num(names); j < nnum; j++)
458 if ( (np = sk_GENERAL_NAME_value(names, j))
459 && np->type == GEN_URI
460 )
461 list = string_append_listele_n(list, sep,
462 US ASN1_STRING_get0_data(np->d.uniformResourceIdentifier),
463 ASN1_STRING_length(np->d.uniformResourceIdentifier));
464 }
465 sk_DIST_POINT_free(dps);
466 return string_from_gstring(list);
467 }
468
469
470
471 /*****************************************************
472 * Certificate operator routines
473 *****************************************************/
474 uschar *
475 tls_cert_der_b64(void * cert)
476 {
477 BIO * bp = BIO_new(BIO_s_mem());
478 uschar * cp = NULL;
479
480 if (!i2d_X509_bio(bp, (X509 *)cert))
481 log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
482 ERR_error_string(ERR_get_error(), NULL));
483 else
484 {
485 long len = BIO_get_mem_data(bp, &cp);
486 cp = b64encode(CUS cp, (int)len);
487 }
488
489 BIO_free(bp);
490 return cp;
491 }
492
493
494 static uschar *
495 fingerprint(X509 * cert, const EVP_MD * fdig)
496 {
497 unsigned int n;
498 uschar md[EVP_MAX_MD_SIZE];
499 uschar * cp;
500
501 if (!X509_digest(cert,fdig,md,&n))
502 {
503 expand_string_message = US"tls_cert_fprt: out of mem\n";
504 return NULL;
505 }
506 cp = store_get(n*2+1, TRUE);
507 for (int j = 0; j < (int)n; j++) sprintf(CS cp+2*j, "%02X", md[j]);
508 return(cp);
509 }
510
511 uschar *
512 tls_cert_fprt_md5(void * cert)
513 {
514 return fingerprint((X509 *)cert, EVP_md5());
515 }
516
517 uschar *
518 tls_cert_fprt_sha1(void * cert)
519 {
520 return fingerprint((X509 *)cert, EVP_sha1());
521 }
522
523 uschar *
524 tls_cert_fprt_sha256(void * cert)
525 {
526 return fingerprint((X509 *)cert, EVP_sha256());
527 }
528
529
530 /* vi: aw ai sw=2
531 */
532 /* End of tlscert-openssl.c */