src/src/tlscert-openssl.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) Jeremy Harris 2014 */
   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
  60 bp = BIO_new_mem_buf(US cp, -1);
  61 x = PEM_read_bio_X509(bp, NULL, 0, NULL);
  62 int fail = 0;
  63 if (!x)
  64   fail = 1;
  65 else
  66   *cert = (void *)x;
  67 BIO_free(bp);
  68 store_reset(reset_point);
  69 return fail;
  70 }
  71
  72 void
  73 tls_free_cert(void * cert)
  74 {
  75 X509_free((X509 *)cert);
  76 }
  77
  78 /*****************************************************
  79 *  Certificate field extraction routines
  80 *****************************************************/
  81 static uschar *
  82 bio_string_copy(BIO * bp, int len)
  83 {
  84 uschar * cp = US"";
  85 len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0;
  86 cp = string_copyn(cp, len);
  87 BIO_free(bp);
  88 return cp;
  89 }
  90
  91 static uschar *
  92 asn1_time_copy(const ASN1_TIME * time)
  93 {
  94 BIO * bp = BIO_new(BIO_s_mem());
  95 int len = ASN1_TIME_print(bp, time);
  96 return bio_string_copy(bp, len);
  97 }
  98
  99 static uschar *
 100 x509_name_copy(X509_NAME * name)
 101 {
 102 BIO * bp = BIO_new(BIO_s_mem());
 103 int len_good =
 104   X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0
 105   ? 1 : 0;
 106 return bio_string_copy(bp, len_good);
 107 }
 108
 109 /**/
 110
 111 uschar *
 112 tls_cert_issuer(void * cert, uschar * mod)
 113 {
 114 uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert));
 115 return mod ? tls_field_from_dn(cp, mod) : cp;
 116 }
 117
 118 uschar *
 119 tls_cert_not_before(void * cert, uschar * mod)
 120 {
 121 return asn1_time_copy(X509_get_notBefore((X509 *)cert));
 122 }
 123
 124 uschar *
 125 tls_cert_not_after(void * cert, uschar * mod)
 126 {
 127 return asn1_time_copy(X509_get_notAfter((X509 *)cert));
 128 }
 129
 130 uschar *
 131 tls_cert_serial_number(void * cert, uschar * mod)
 132 {
 133 uschar txt[256];
 134 BIO * bp = BIO_new(BIO_s_mem());
 135 int len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
 136
 137 if (len < sizeof(txt))
 138   BIO_read(bp, txt, len);
 139 else
 140   len = 0;
 141 BIO_free(bp);
 142 return string_copynlc(txt, len);        /* lowercase */
 143 }
 144
 145 uschar *
 146 tls_cert_signature(void * cert, uschar * mod)
 147 {
 148 BIO * bp = BIO_new(BIO_s_mem());
 149 uschar * cp = NULL;
 150
 151 if (X509_print_ex(bp, (X509 *)cert, 0,
 152   X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
 153   X509_FLAG_NO_SIGNAME | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
 154   X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
 155   /* X509_FLAG_NO_SIGDUMP is the missing one */
 156   X509_FLAG_NO_AUX) == 1)
 157   {
 158   long len = BIO_get_mem_data(bp, &cp);
 159   cp = string_copyn(cp, len);
 160   }
 161 BIO_free(bp);
 162 return cp;
 163 }
 164
 165 uschar *
 166 tls_cert_signature_algorithm(void * cert, uschar * mod)
 167 {
 168 return string_copy(US OBJ_nid2ln(X509_get_signature_type((X509 *)cert)));
 169 }
 170
 171 uschar *
 172 tls_cert_subject(void * cert, uschar * mod)
 173 {
 174 uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert));
 175 return mod ? tls_field_from_dn(cp, mod) : cp;
 176 }
 177
 178 uschar *
 179 tls_cert_version(void * cert, uschar * mod)
 180 {
 181 return string_sprintf("%d", X509_get_version((X509 *)cert));
 182 }
 183
 184 uschar *
 185 tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
 186 {
 187 int nid = OBJ_create(CS oid, "", "");
 188 int nidx = X509_get_ext_by_NID((X509 *)cert, nid, idx);
 189 X509_EXTENSION * ex = X509_get_ext((X509 *)cert, nidx);
 190 ASN1_OCTET_STRING * adata = X509_EXTENSION_get_data(ex);
 191 BIO * bp = BIO_new(BIO_s_mem());
 192 long len;
 193 uschar * cp1;
 194 uschar * cp2;
 195 uschar * cp3;
 196
 197 M_ASN1_OCTET_STRING_print(bp, adata);
 198 /* binary data, DER encoded */
 199
 200 /* just dump for now */
 201 len = BIO_get_mem_data(bp, &cp1);
 202 cp3 = cp2 = store_get(len*3+1);
 203
 204 while(len)
 205   {
 206   sprintf(CS cp2, "%.2x ", *cp1++);
 207   cp2 += 3;
 208   len--;
 209   }
 210 cp2[-1] = '\0';
 211
 212 return cp3;
 213 }
 214
 215 uschar *
 216 tls_cert_subject_altname(void * cert, uschar * mod)
 217 {
 218 uschar * list = NULL;
 219 STACK_OF(GENERAL_NAME) * san = (STACK_OF(GENERAL_NAME) *)
 220   X509_get_ext_d2i((X509 *)cert, NID_subject_alt_name, NULL, NULL);
 221 uschar sep = '\n';
 222 uschar * tag = US"";
 223 uschar * ele;
 224 int match = -1;
 225
 226 if (!san) return NULL;
 227
 228 while (mod)
 229   {
 230   if (*mod == '>' && *++mod) sep = *mod++;
 231   else if (Ustrcmp(mod, "dns")==0) { match = GEN_DNS; mod += 3; }
 232   else if (Ustrcmp(mod, "uri")==0) { match = GEN_URI; mod += 3; }
 233   else if (Ustrcmp(mod, "mail")==0) { match = GEN_EMAIL; mod += 4; }
 234   else continue;
 235
 236   if (*mod++ != ',')
 237     break;
 238   }
 239
 240 while (sk_GENERAL_NAME_num(san) > 0)
 241   {
 242   GENERAL_NAME * namePart = sk_GENERAL_NAME_pop(san);
 243   if (match != -1 && match != namePart->type)
 244     continue;
 245   switch (namePart->type)
 246     {
 247     case GEN_DNS:
 248       tag = US"DNS";
 249       ele = ASN1_STRING_data(namePart->d.dNSName);
 250       break;
 251     case GEN_URI:
 252       tag = US"URI";
 253       ele = ASN1_STRING_data(namePart->d.uniformResourceIdentifier);
 254       break;
 255     case GEN_EMAIL:
 256       tag = US"MAIL";
 257       ele = ASN1_STRING_data(namePart->d.rfc822Name);
 258       break;
 259     default:
 260       continue; /* ignore unrecognised types */
 261     }
 262   list = string_append_listele(list, sep,
 263           match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
 264   }
 265
 266 sk_GENERAL_NAME_free(san);
 267 return list;
 268 }
 269
 270 uschar *
 271 tls_cert_ocsp_uri(void * cert, uschar * mod)
 272 {
 273 STACK_OF(ACCESS_DESCRIPTION) * ads = (STACK_OF(ACCESS_DESCRIPTION) *)
 274   X509_get_ext_d2i((X509 *)cert, NID_info_access, NULL, NULL);
 275 int adsnum = sk_ACCESS_DESCRIPTION_num(ads);
 276 int i;
 277 uschar sep = '\n';
 278 uschar * list = NULL;
 279
 280 if (mod)
 281   if (*mod == '>' && *++mod) sep = *mod++;
 282
 283 for (i = 0; i < adsnum; i++)
 284   {
 285   ACCESS_DESCRIPTION * ad = sk_ACCESS_DESCRIPTION_value(ads, i);
 286
 287   if (ad && OBJ_obj2nid(ad->method) == NID_ad_OCSP)
 288     list = string_append_listele(list, sep,
 289               ASN1_STRING_data(ad->location->d.ia5));
 290   }
 291 return list;
 292 }
 293
 294 uschar *
 295 tls_cert_crl_uri(void * cert, uschar * mod)
 296 {
 297 STACK_OF(DIST_POINT) * dps = (STACK_OF(DIST_POINT) *)
 298   X509_get_ext_d2i((X509 *)cert,  NID_crl_distribution_points,
 299     NULL, NULL);
 300 DIST_POINT * dp;
 301 int dpsnum = sk_DIST_POINT_num(dps);
 302 int i;
 303 uschar sep = '\n';
 304 uschar * list = NULL;
 305
 306 if (mod)
 307   if (*mod == '>' && *++mod) sep = *mod++;
 308
 309 if (dps) for (i = 0; i < dpsnum; i++)
 310   if ((dp = sk_DIST_POINT_value(dps, i)))
 311     {
 312     STACK_OF(GENERAL_NAME) * names = dp->distpoint->name.fullname;
 313     GENERAL_NAME * np;
 314     int nnum = sk_GENERAL_NAME_num(names);
 315     int j;
 316
 317     for (j = 0; j < nnum; j++)
 318       if (  (np = sk_GENERAL_NAME_value(names, j))
 319          && np->type == GEN_URI
 320          )
 321         list = string_append_listele(list, sep,
 322                 ASN1_STRING_data(np->d.uniformResourceIdentifier));
 323     }
 324 return list;
 325 }
 326
 327
 328
 329 /*****************************************************
 330 *  Certificate operator routines
 331 *****************************************************/
 332 static uschar *
 333 fingerprint(X509 * cert, const EVP_MD * fdig)
 334 {
 335 int j;
 336 unsigned int n;
 337 uschar md[EVP_MAX_MD_SIZE];
 338 uschar * cp;
 339
 340 if (!X509_digest(cert,fdig,md,&n))
 341   {
 342   expand_string_message = US"tls_cert_fprt: out of mem\n";
 343   return NULL;
 344   }
 345 cp = store_get(n*2+1);
 346 for (j = 0; j < (int)n; j++) sprintf(CS cp+2*j, "%02X", md[j]);
 347 return(cp);
 348 }
 349
 350 uschar *
 351 tls_cert_fprt_md5(void * cert)
 352 {
 353 return fingerprint((X509 *)cert, EVP_md5());
 354 }
 355
 356 uschar *
 357 tls_cert_fprt_sha1(void * cert)
 358 {
 359 return fingerprint((X509 *)cert, EVP_sha1());
 360 }
 361
 362 uschar *
 363 tls_cert_fprt_sha256(void * cert)
 364 {
 365 return fingerprint((X509 *)cert, EVP_sha256());
 366 }
 367
 368
 369 /* vi: aw ai sw=2
 370 */
 371 /* End of tlscert-openssl.c */