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 bio_string_time_to_int(BIO * bp, int len)
  93 {
  94 uschar * cp = US"";
  95 struct tm t;
  96 len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0;
  97 /*XXX %Z might be glibc-specific? */
  98 (void) strptime(CS cp, "%b%t%e%t%T%t%Y%t%Z", &t);
  99 BIO_free(bp);
 100 /*XXX timegm might not be portable? */
 101 return string_sprintf("%u", (unsigned) timegm(&t));
 102 }
 103
 104 static uschar *
 105 asn1_time_copy(const ASN1_TIME * time, uschar * mod)
 106 {
 107 BIO * bp = BIO_new(BIO_s_mem());
 108 int len = ASN1_TIME_print(bp, time);
 109 return mod &&  Ustrcmp(mod, "int") == 0
 110   ? bio_string_time_to_int(bp, len)
 111   : bio_string_copy(bp, len);
 112 }
 113
 114 static uschar *
 115 x509_name_copy(X509_NAME * name)
 116 {
 117 BIO * bp = BIO_new(BIO_s_mem());
 118 int len_good =
 119   X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0
 120   ? 1 : 0;
 121 return bio_string_copy(bp, len_good);
 122 }
 123
 124 /**/
 125
 126 uschar *
 127 tls_cert_issuer(void * cert, uschar * mod)
 128 {
 129 uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert));
 130 return mod ? tls_field_from_dn(cp, mod) : cp;
 131 }
 132
 133 uschar *
 134 tls_cert_not_before(void * cert, uschar * mod)
 135 {
 136 return asn1_time_copy(X509_get_notBefore((X509 *)cert), mod);
 137 }
 138
 139 uschar *
 140 tls_cert_not_after(void * cert, uschar * mod)
 141 {
 142 return asn1_time_copy(X509_get_notAfter((X509 *)cert), mod);
 143 }
 144
 145 uschar *
 146 tls_cert_serial_number(void * cert, uschar * mod)
 147 {
 148 uschar txt[256];
 149 BIO * bp = BIO_new(BIO_s_mem());
 150 int len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
 151
 152 if (len < sizeof(txt))
 153   BIO_read(bp, txt, len);
 154 else
 155   len = 0;
 156 BIO_free(bp);
 157 return string_copynlc(txt, len);        /* lowercase */
 158 }
 159
 160 uschar *
 161 tls_cert_signature(void * cert, uschar * mod)
 162 {
 163 BIO * bp = BIO_new(BIO_s_mem());
 164 uschar * cp = NULL;
 165
 166 if (X509_print_ex(bp, (X509 *)cert, 0,
 167   X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
 168   X509_FLAG_NO_SIGNAME | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
 169   X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
 170   /* X509_FLAG_NO_SIGDUMP is the missing one */
 171   X509_FLAG_NO_AUX) == 1)
 172   {
 173   long len = BIO_get_mem_data(bp, &cp);
 174   cp = string_copyn(cp, len);
 175   }
 176 BIO_free(bp);
 177 return cp;
 178 }
 179
 180 uschar *
 181 tls_cert_signature_algorithm(void * cert, uschar * mod)
 182 {
 183 return string_copy(US OBJ_nid2ln(X509_get_signature_type((X509 *)cert)));
 184 }
 185
 186 uschar *
 187 tls_cert_subject(void * cert, uschar * mod)
 188 {
 189 uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert));
 190 return mod ? tls_field_from_dn(cp, mod) : cp;
 191 }
 192
 193 uschar *
 194 tls_cert_version(void * cert, uschar * mod)
 195 {
 196 return string_sprintf("%d", X509_get_version((X509 *)cert));
 197 }
 198
 199 uschar *
 200 tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
 201 {
 202 int nid = OBJ_create(CS oid, "", "");
 203 int nidx = X509_get_ext_by_NID((X509 *)cert, nid, idx);
 204 X509_EXTENSION * ex = X509_get_ext((X509 *)cert, nidx);
 205 ASN1_OCTET_STRING * adata = X509_EXTENSION_get_data(ex);
 206 BIO * bp = BIO_new(BIO_s_mem());
 207 long len;
 208 uschar * cp1;
 209 uschar * cp2;
 210 uschar * cp3;
 211
 212 M_ASN1_OCTET_STRING_print(bp, adata);
 213 /* binary data, DER encoded */
 214
 215 /* just dump for now */
 216 len = BIO_get_mem_data(bp, &cp1);
 217 cp3 = cp2 = store_get(len*3+1);
 218
 219 while(len)
 220   {
 221   sprintf(CS cp2, "%.2x ", *cp1++);
 222   cp2 += 3;
 223   len--;
 224   }
 225 cp2[-1] = '\0';
 226
 227 return cp3;
 228 }
 229
 230 uschar *
 231 tls_cert_subject_altname(void * cert, uschar * mod)
 232 {
 233 uschar * list = NULL;
 234 STACK_OF(GENERAL_NAME) * san = (STACK_OF(GENERAL_NAME) *)
 235   X509_get_ext_d2i((X509 *)cert, NID_subject_alt_name, NULL, NULL);
 236 uschar sep = '\n';
 237 uschar * tag = US"";
 238 uschar * ele;
 239 int match = -1;
 240 int len;
 241
 242 if (!san) return NULL;
 243
 244 while (mod)
 245   {
 246   if (*mod == '>' && *++mod) sep = *mod++;
 247   else if (Ustrcmp(mod, "dns")==0) { match = GEN_DNS; mod += 3; }
 248   else if (Ustrcmp(mod, "uri")==0) { match = GEN_URI; mod += 3; }
 249   else if (Ustrcmp(mod, "mail")==0) { match = GEN_EMAIL; mod += 4; }
 250   else continue;
 251
 252   if (*mod++ != ',')
 253     break;
 254   }
 255
 256 while (sk_GENERAL_NAME_num(san) > 0)
 257   {
 258   GENERAL_NAME * namePart = sk_GENERAL_NAME_pop(san);
 259   if (match != -1 && match != namePart->type)
 260     continue;
 261   switch (namePart->type)
 262     {
 263     case GEN_DNS:
 264       tag = US"DNS";
 265       ele = ASN1_STRING_data(namePart->d.dNSName);
 266       len = ASN1_STRING_length(namePart->d.dNSName);
 267       break;
 268     case GEN_URI:
 269       tag = US"URI";
 270       ele = ASN1_STRING_data(namePart->d.uniformResourceIdentifier);
 271       len = ASN1_STRING_length(namePart->d.uniformResourceIdentifier);
 272       break;
 273     case GEN_EMAIL:
 274       tag = US"MAIL";
 275       ele = ASN1_STRING_data(namePart->d.rfc822Name);
 276       len = ASN1_STRING_length(namePart->d.rfc822Name);
 277       break;
 278     default:
 279       continue; /* ignore unrecognised types */
 280     }
 281   if (ele[len]) /* not nul-terminated */
 282     ele = string_copyn(ele, len);
 283
 284   if (strnlen(CS ele, len) == len)      /* ignore any with embedded nul */
 285     list = string_append_listele(list, sep,
 286           match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
 287   }
 288
 289 sk_GENERAL_NAME_free(san);
 290 return list;
 291 }
 292
 293 uschar *
 294 tls_cert_ocsp_uri(void * cert, uschar * mod)
 295 {
 296 STACK_OF(ACCESS_DESCRIPTION) * ads = (STACK_OF(ACCESS_DESCRIPTION) *)
 297   X509_get_ext_d2i((X509 *)cert, NID_info_access, NULL, NULL);
 298 int adsnum = sk_ACCESS_DESCRIPTION_num(ads);
 299 int i;
 300 uschar sep = '\n';
 301 uschar * list = NULL;
 302
 303 if (mod)
 304   if (*mod == '>' && *++mod) sep = *mod++;
 305
 306 for (i = 0; i < adsnum; i++)
 307   {
 308   ACCESS_DESCRIPTION * ad = sk_ACCESS_DESCRIPTION_value(ads, i);
 309
 310   if (ad && OBJ_obj2nid(ad->method) == NID_ad_OCSP)
 311     list = string_append_listele(list, sep,
 312               ASN1_STRING_data(ad->location->d.ia5));
 313   }
 314 return list;
 315 }
 316
 317 uschar *
 318 tls_cert_crl_uri(void * cert, uschar * mod)
 319 {
 320 STACK_OF(DIST_POINT) * dps = (STACK_OF(DIST_POINT) *)
 321   X509_get_ext_d2i((X509 *)cert,  NID_crl_distribution_points,
 322     NULL, NULL);
 323 DIST_POINT * dp;
 324 int dpsnum = sk_DIST_POINT_num(dps);
 325 int i;
 326 uschar sep = '\n';
 327 uschar * list = NULL;
 328
 329 if (mod)
 330   if (*mod == '>' && *++mod) sep = *mod++;
 331
 332 if (dps) for (i = 0; i < dpsnum; i++)
 333   if ((dp = sk_DIST_POINT_value(dps, i)))
 334     {
 335     STACK_OF(GENERAL_NAME) * names = dp->distpoint->name.fullname;
 336     GENERAL_NAME * np;
 337     int nnum = sk_GENERAL_NAME_num(names);
 338     int j;
 339
 340     for (j = 0; j < nnum; j++)
 341       if (  (np = sk_GENERAL_NAME_value(names, j))
 342          && np->type == GEN_URI
 343          )
 344         list = string_append_listele(list, sep,
 345                 ASN1_STRING_data(np->d.uniformResourceIdentifier));
 346     }
 347 return list;
 348 }
 349
 350
 351
 352 /*****************************************************
 353 *  Certificate operator routines
 354 *****************************************************/
 355 static uschar *
 356 fingerprint(X509 * cert, const EVP_MD * fdig)
 357 {
 358 int j;
 359 unsigned int n;
 360 uschar md[EVP_MAX_MD_SIZE];
 361 uschar * cp;
 362
 363 if (!X509_digest(cert,fdig,md,&n))
 364   {
 365   expand_string_message = US"tls_cert_fprt: out of mem\n";
 366   return NULL;
 367   }
 368 cp = store_get(n*2+1);
 369 for (j = 0; j < (int)n; j++) sprintf(CS cp+2*j, "%02X", md[j]);
 370 return(cp);
 371 }
 372
 373 uschar *
 374 tls_cert_fprt_md5(void * cert)
 375 {
 376 return fingerprint((X509 *)cert, EVP_md5());
 377 }
 378
 379 uschar *
 380 tls_cert_fprt_sha1(void * cert)
 381 {
 382 return fingerprint((X509 *)cert, EVP_sha1());
 383 }
 384
 385 uschar *
 386 tls_cert_fprt_sha256(void * cert)
 387 {
 388 return fingerprint((X509 *)cert, EVP_sha256());
 389 }
 390
 391
 392 /* vi: aw ai sw=2
 393 */
 394 /* End of tlscert-openssl.c */