src/src/tlscert-openssl.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) Jeremy Harris 2014 - 2015 */
   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
  21 /*****************************************************
  22 *  Export/import a certificate, binary/printable
  23 *****************************************************/
  24 int
  25 tls_export_cert(uschar * buf, size_t buflen, void * cert)
  26 {
  27 BIO * bp = BIO_new(BIO_s_mem());
  28 int fail;
  29
  30 if ((fail = PEM_write_bio_X509(bp, (X509 *)cert) ? 0 : 1))
  31   log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
  32     ERR_error_string(ERR_get_error(), NULL));
  33 else
  34   {
  35   char * cp = CS buf;
  36   int n;
  37   buflen -= 2;
  38   for(;;)
  39     {
  40     if ((n = BIO_gets(bp, cp, (int)buflen)) <= 0) break;
  41     cp += n+1;
  42     buflen -= n+1;
  43     cp[-2] = '\\'; cp[-1] = 'n'; /* newline->"\n" */
  44     }                            /* compat with string_printing() */
  45   *cp = '\0';
  46   }
  47
  48 BIO_free(bp);
  49 return fail;
  50 }
  51
  52 int
  53 tls_import_cert(const uschar * buf, void ** cert)
  54 {
  55 void * reset_point = store_get(0);
  56 const uschar * cp = string_unprinting(US buf);
  57 BIO * bp;
  58 X509 * x;
  59 int fail = 0;
  60
  61 bp = BIO_new_mem_buf(US cp, -1);
  62 if (!(x = PEM_read_bio_X509(bp, NULL, 0, NULL)))
  63   {
  64   log_write(0, LOG_MAIN, "TLS error in certificate import: %s",
  65     ERR_error_string(ERR_get_error(), NULL));
  66   fail = 1;
  67   }
  68 else
  69   *cert = (void *)x;
  70 BIO_free(bp);
  71 store_reset(reset_point);
  72 return fail;
  73 }
  74
  75 void
  76 tls_free_cert(void * cert)
  77 {
  78 X509_free((X509 *)cert);
  79 }
  80
  81
  82 /*****************************************************
  83 *  Certificate field extraction routines
  84 *****************************************************/
  85
  86 /* First, some internal service functions */
  87
  88 static uschar *
  89 badalloc(void)
  90 {
  91 expand_string_message = US"allocation failure";
  92 return NULL;
  93 }
  94
  95 static uschar *
  96 bio_string_copy(BIO * bp, int len)
  97 {
  98 uschar * cp = US"";
  99 len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0;
 100 cp = string_copyn(cp, len);
 101 BIO_free(bp);
 102 return cp;
 103 }
 104
 105 static uschar *
 106 asn1_time_copy(const ASN1_TIME * asntime, uschar * mod)
 107 {
 108 uschar * s = NULL;
 109 BIO * bp = BIO_new(BIO_s_mem());
 110 int len;
 111
 112 if (!bp)
 113   return badalloc();
 114 len = ASN1_TIME_print(bp, asntime);
 115 len = len > 0 ? (int) BIO_get_mem_data(bp, &s) : 0;
 116
 117 if (mod && Ustrcmp(mod, "raw") == 0)            /* native ASN */
 118   s = string_copyn(s, len);
 119 else
 120   {
 121   struct tm tm;
 122   struct tm * tm_p = &tm;
 123   BOOL mod_tz;
 124   uschar * tz = to_tz(US"GMT0");    /* need to call strptime with baseline TZ */
 125
 126   /* Parse OpenSSL ASN1_TIME_print output.  A shame there seems to
 127   be no other interface for the times.
 128   */
 129
 130   /*XXX %Z might be glibc-specific?  Solaris has it, at least*/
 131   /*XXX should we switch to POSIX locale for this? */
 132   tm.tm_isdst = 0;
 133   if (!strptime(CCS s, "%b %e %T %Y %Z", &tm))
 134     expand_string_message = US"failed time conversion";
 135
 136   else
 137     {
 138     time_t t = mktime(&tm);     /* make the tm self-consistent */
 139
 140     if (mod && Ustrcmp(mod, "int") == 0)        /* seconds since epoch */
 141       s = string_sprintf("%u", t);
 142
 143     else
 144       {
 145       if (!timestamps_utc)      /* decoded string in local TZ */
 146         {                               /* shift to local TZ */
 147         restore_tz(tz);
 148         mod_tz = FALSE;
 149         tm_p = localtime(&t);
 150         }
 151       /* "utc" is default, and rfc5280 says cert times should be Zulu */
 152
 153       /* convert to string in our format */
 154       len = 32;
 155       s = store_get(len);
 156       strftime(CS s, (size_t)len, "%b %e %T %Y %z", tm_p);
 157       }
 158     }
 159
 160   if (mod_tz);
 161     restore_tz(tz);
 162   }
 163 BIO_free(bp);
 164 return s;
 165 }
 166
 167 static uschar *
 168 x509_name_copy(X509_NAME * name)
 169 {
 170 BIO * bp = BIO_new(BIO_s_mem());
 171 int len_good;
 172
 173 if (!bp) return badalloc();
 174
 175 len_good =
 176   X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0
 177   ? 1 : 0;
 178 return bio_string_copy(bp, len_good);
 179 }
 180
 181 /**/
 182 /* Now the extractors, called from expand.c
 183 Arguments:
 184   cert          The certificate
 185   mod           Optional modifiers for the operator
 186
 187 Return:
 188   Allocated string with extracted value
 189 */
 190
 191 uschar *
 192 tls_cert_issuer(void * cert, uschar * mod)
 193 {
 194 uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert));
 195 return mod ? tls_field_from_dn(cp, mod) : cp;
 196 }
 197
 198 uschar *
 199 tls_cert_not_before(void * cert, uschar * mod)
 200 {
 201 return asn1_time_copy(X509_get_notBefore((X509 *)cert), mod);
 202 }
 203
 204 uschar *
 205 tls_cert_not_after(void * cert, uschar * mod)
 206 {
 207 return asn1_time_copy(X509_get_notAfter((X509 *)cert), mod);
 208 }
 209
 210 uschar *
 211 tls_cert_serial_number(void * cert, uschar * mod)
 212 {
 213 uschar txt[256];
 214 BIO * bp = BIO_new(BIO_s_mem());
 215 int len;
 216
 217 if (!bp) return badalloc();
 218
 219 len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
 220 if (len < sizeof(txt))
 221   BIO_read(bp, txt, len);
 222 else
 223   len = 0;
 224 BIO_free(bp);
 225 return string_copynlc(txt, len);        /* lowercase */
 226 }
 227
 228 uschar *
 229 tls_cert_signature(void * cert, uschar * mod)
 230 {
 231 uschar * cp = NULL;
 232 BIO * bp = BIO_new(BIO_s_mem());
 233
 234 if (!bp) return badalloc();
 235
 236 if (X509_print_ex(bp, (X509 *)cert, 0,
 237   X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
 238   X509_FLAG_NO_SIGNAME | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
 239   X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
 240   /* X509_FLAG_NO_SIGDUMP is the missing one */
 241   X509_FLAG_NO_AUX) == 1)
 242   {
 243   long len = BIO_get_mem_data(bp, &cp);
 244
 245   /* Strip leading "Signature Algorithm" line */
 246   while (*cp && *cp != '\n') { cp++; len--; }
 247
 248   cp = string_copyn(cp+1, len-1);
 249   }
 250 BIO_free(bp);
 251 return cp;
 252 }
 253
 254 uschar *
 255 tls_cert_signature_algorithm(void * cert, uschar * mod)
 256 {
 257 uschar * cp = NULL;
 258 BIO * bp = BIO_new(BIO_s_mem());
 259
 260 if (!bp) return badalloc();
 261
 262 if (X509_print_ex(bp, (X509 *)cert, 0,
 263   X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
 264   /* X509_FLAG_NO_SIGNAME is the missing one */
 265   X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
 266   X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
 267   X509_FLAG_NO_SIGDUMP | X509_FLAG_NO_AUX) == 1)
 268   {
 269   long len = BIO_get_mem_data(bp, &cp);
 270
 271   /* Strip leading "    Signature Algorithm: " and trailing newline */
 272   while (*cp && *cp != ':') { cp++; len--; }
 273   do { cp++; len--; } while (*cp && *cp == ' ');
 274   if (cp[len-1] == '\n') len--;
 275
 276   cp = string_copyn(cp, len);
 277   }
 278 BIO_free(bp);
 279 return cp;
 280 }
 281
 282 uschar *
 283 tls_cert_subject(void * cert, uschar * mod)
 284 {
 285 uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert));
 286 return mod ? tls_field_from_dn(cp, mod) : cp;
 287 }
 288
 289 uschar *
 290 tls_cert_version(void * cert, uschar * mod)
 291 {
 292 return string_sprintf("%d", X509_get_version((X509 *)cert));
 293 }
 294
 295 uschar *
 296 tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
 297 {
 298 int nid = OBJ_create(CS oid, "", "");
 299 int nidx = X509_get_ext_by_NID((X509 *)cert, nid, idx);
 300 X509_EXTENSION * ex = X509_get_ext((X509 *)cert, nidx);
 301 ASN1_OCTET_STRING * adata = X509_EXTENSION_get_data(ex);
 302 BIO * bp = BIO_new(BIO_s_mem());
 303 long len;
 304 uschar * cp1;
 305 uschar * cp2;
 306 uschar * cp3;
 307
 308 if (!bp) return badalloc();
 309
 310 M_ASN1_OCTET_STRING_print(bp, adata);
 311 /* binary data, DER encoded */
 312
 313 /* just dump for now */
 314 len = BIO_get_mem_data(bp, &cp1);
 315 cp3 = cp2 = store_get(len*3+1);
 316
 317 while(len)
 318   {
 319   sprintf(CS cp2, "%.2x ", *cp1++);
 320   cp2 += 3;
 321   len--;
 322   }
 323 cp2[-1] = '\0';
 324
 325 return cp3;
 326 }
 327
 328 uschar *
 329 tls_cert_subject_altname(void * cert, uschar * mod)
 330 {
 331 uschar * list = NULL;
 332 STACK_OF(GENERAL_NAME) * san = (STACK_OF(GENERAL_NAME) *)
 333   X509_get_ext_d2i((X509 *)cert, NID_subject_alt_name, NULL, NULL);
 334 uschar osep = '\n';
 335 uschar * tag = US"";
 336 uschar * ele;
 337 int match = -1;
 338 int len;
 339
 340 if (!san) return NULL;
 341
 342 while (mod && *mod)
 343   {
 344   if (*mod == '>' && *++mod) osep = *mod++;
 345   else if (Ustrncmp(mod,"dns",3)==0) { match = GEN_DNS; mod += 3; }
 346   else if (Ustrncmp(mod,"uri",3)==0) { match = GEN_URI; mod += 3; }
 347   else if (Ustrncmp(mod,"mail",4)==0) { match = GEN_EMAIL; mod += 4; }
 348   else mod++;
 349
 350   if (*mod == ',') mod++;
 351   }
 352
 353 while (sk_GENERAL_NAME_num(san) > 0)
 354   {
 355   GENERAL_NAME * namePart = sk_GENERAL_NAME_pop(san);
 356   if (match != -1 && match != namePart->type)
 357     continue;
 358   switch (namePart->type)
 359     {
 360     case GEN_DNS:
 361       tag = US"DNS";
 362       ele = ASN1_STRING_data(namePart->d.dNSName);
 363       len = ASN1_STRING_length(namePart->d.dNSName);
 364       break;
 365     case GEN_URI:
 366       tag = US"URI";
 367       ele = ASN1_STRING_data(namePart->d.uniformResourceIdentifier);
 368       len = ASN1_STRING_length(namePart->d.uniformResourceIdentifier);
 369       break;
 370     case GEN_EMAIL:
 371       tag = US"MAIL";
 372       ele = ASN1_STRING_data(namePart->d.rfc822Name);
 373       len = ASN1_STRING_length(namePart->d.rfc822Name);
 374       break;
 375     default:
 376       continue; /* ignore unrecognised types */
 377     }
 378   if (ele[len]) /* not nul-terminated */
 379     ele = string_copyn(ele, len);
 380
 381   if (Ustrlen(ele) == len)      /* ignore any with embedded nul */
 382     list = string_append_listele(list, osep,
 383           match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
 384   }
 385
 386 sk_GENERAL_NAME_free(san);
 387 return list;
 388 }
 389
 390 uschar *
 391 tls_cert_ocsp_uri(void * cert, uschar * mod)
 392 {
 393 STACK_OF(ACCESS_DESCRIPTION) * ads = (STACK_OF(ACCESS_DESCRIPTION) *)
 394   X509_get_ext_d2i((X509 *)cert, NID_info_access, NULL, NULL);
 395 int adsnum = sk_ACCESS_DESCRIPTION_num(ads);
 396 int i;
 397 uschar sep = '\n';
 398 uschar * list = NULL;
 399
 400 if (mod)
 401   if (*mod == '>' && *++mod) sep = *mod++;
 402
 403 for (i = 0; i < adsnum; i++)
 404   {
 405   ACCESS_DESCRIPTION * ad = sk_ACCESS_DESCRIPTION_value(ads, i);
 406
 407   if (ad && OBJ_obj2nid(ad->method) == NID_ad_OCSP)
 408     {
 409     uschar * ele = ASN1_STRING_data(ad->location->d.ia5);
 410     int len =  ASN1_STRING_length(ad->location->d.ia5);
 411     list = string_append_listele_n(list, sep, ele, len);
 412     }
 413   }
 414 sk_ACCESS_DESCRIPTION_free(ads);
 415 return list;
 416 }
 417
 418 uschar *
 419 tls_cert_crl_uri(void * cert, uschar * mod)
 420 {
 421 STACK_OF(DIST_POINT) * dps = (STACK_OF(DIST_POINT) *)
 422   X509_get_ext_d2i((X509 *)cert,  NID_crl_distribution_points,
 423     NULL, NULL);
 424 DIST_POINT * dp;
 425 int dpsnum = sk_DIST_POINT_num(dps);
 426 int i;
 427 uschar sep = '\n';
 428 uschar * list = NULL;
 429
 430 if (mod)
 431   if (*mod == '>' && *++mod) sep = *mod++;
 432
 433 if (dps) for (i = 0; i < dpsnum; i++)
 434   if ((dp = sk_DIST_POINT_value(dps, i)))
 435     {
 436     STACK_OF(GENERAL_NAME) * names = dp->distpoint->name.fullname;
 437     GENERAL_NAME * np;
 438     int nnum = sk_GENERAL_NAME_num(names);
 439     int j;
 440
 441     for (j = 0; j < nnum; j++)
 442       if (  (np = sk_GENERAL_NAME_value(names, j))
 443          && np->type == GEN_URI
 444          )
 445         {
 446         uschar * ele = ASN1_STRING_data(np->d.uniformResourceIdentifier);
 447         int len =  ASN1_STRING_length(np->d.uniformResourceIdentifier);
 448         list = string_append_listele_n(list, sep, ele, len);
 449         }
 450     }
 451 sk_DIST_POINT_free(dps);
 452 return list;
 453 }
 454
 455
 456
 457 /*****************************************************
 458 *  Certificate operator routines
 459 *****************************************************/
 460 static uschar *
 461 fingerprint(X509 * cert, const EVP_MD * fdig)
 462 {
 463 int j;
 464 unsigned int n;
 465 uschar md[EVP_MAX_MD_SIZE];
 466 uschar * cp;
 467
 468 if (!X509_digest(cert,fdig,md,&n))
 469   {
 470   expand_string_message = US"tls_cert_fprt: out of mem\n";
 471   return NULL;
 472   }
 473 cp = store_get(n*2+1);
 474 for (j = 0; j < (int)n; j++) sprintf(CS cp+2*j, "%02X", md[j]);
 475 return(cp);
 476 }
 477
 478 uschar *
 479 tls_cert_fprt_md5(void * cert)
 480 {
 481 return fingerprint((X509 *)cert, EVP_md5());
 482 }
 483
 484 uschar *
 485 tls_cert_fprt_sha1(void * cert)
 486 {
 487 return fingerprint((X509 *)cert, EVP_sha1());
 488 }
 489
 490 uschar *
 491 tls_cert_fprt_sha256(void * cert)
 492 {
 493 return fingerprint((X509 *)cert, EVP_sha256());
 494 }
 495
 496
 497 /* vi: aw ai sw=2
 498 */
 499 /* End of tlscert-openssl.c */