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 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 bio_string_time_to_int(BIO * bp, int len)
 107 {
 108 uschar * cp = US"";
 109 struct tm t;
 110 len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0;
 111 /*XXX %Z might be glibc-specific? */
 112 (void) strptime(CS cp, "%b%t%e%t%T%t%Y%t%Z", &t);
 113 BIO_free(bp);
 114 /*XXX timegm might not be portable? */
 115 return string_sprintf("%u", (unsigned) timegm(&t));
 116 }
 117
 118 static uschar *
 119 asn1_time_copy(const ASN1_TIME * time, uschar * mod)
 120 {
 121 BIO * bp = BIO_new(BIO_s_mem());
 122 int len;
 123
 124 if (!bp) return badalloc();
 125
 126 len = ASN1_TIME_print(bp, time);
 127 return mod &&  Ustrcmp(mod, "int") == 0
 128   ? bio_string_time_to_int(bp, len)
 129   : bio_string_copy(bp, len);
 130 }
 131
 132 static uschar *
 133 x509_name_copy(X509_NAME * name)
 134 {
 135 BIO * bp = BIO_new(BIO_s_mem());
 136 int len_good;
 137
 138 if (!bp) return badalloc();
 139
 140 len_good =
 141   X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0
 142   ? 1 : 0;
 143 return bio_string_copy(bp, len_good);
 144 }
 145
 146 /**/
 147 /* Now the extractors, called from expand.c
 148 Arguments:
 149   cert          The certificate
 150   mod           Optional modifiers for the operator
 151
 152 Return:
 153   Allocated string with extracted value
 154 */
 155
 156 uschar *
 157 tls_cert_issuer(void * cert, uschar * mod)
 158 {
 159 uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert));
 160 return mod ? tls_field_from_dn(cp, mod) : cp;
 161 }
 162
 163 uschar *
 164 tls_cert_not_before(void * cert, uschar * mod)
 165 {
 166 return asn1_time_copy(X509_get_notBefore((X509 *)cert), mod);
 167 }
 168
 169 uschar *
 170 tls_cert_not_after(void * cert, uschar * mod)
 171 {
 172 return asn1_time_copy(X509_get_notAfter((X509 *)cert), mod);
 173 }
 174
 175 uschar *
 176 tls_cert_serial_number(void * cert, uschar * mod)
 177 {
 178 uschar txt[256];
 179 BIO * bp = BIO_new(BIO_s_mem());
 180 int len;
 181
 182 if (!bp) return badalloc();
 183
 184 len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert));
 185 if (len < sizeof(txt))
 186   BIO_read(bp, txt, len);
 187 else
 188   len = 0;
 189 BIO_free(bp);
 190 return string_copynlc(txt, len);        /* lowercase */
 191 }
 192
 193 uschar *
 194 tls_cert_signature(void * cert, uschar * mod)
 195 {
 196 uschar * cp = NULL;
 197 BIO * bp = BIO_new(BIO_s_mem());
 198
 199 if (!bp) return badalloc();
 200
 201 if (X509_print_ex(bp, (X509 *)cert, 0,
 202   X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL |
 203   X509_FLAG_NO_SIGNAME | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY |
 204   X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS |
 205   /* X509_FLAG_NO_SIGDUMP is the missing one */
 206   X509_FLAG_NO_AUX) == 1)
 207   {
 208   long len = BIO_get_mem_data(bp, &cp);
 209   cp = string_copyn(cp, len);
 210   }
 211 BIO_free(bp);
 212 return cp;
 213 }
 214
 215 uschar *
 216 tls_cert_signature_algorithm(void * cert, uschar * mod)
 217 {
 218 return string_copy(US OBJ_nid2ln(X509_get_signature_type((X509 *)cert)));
 219 }
 220
 221 uschar *
 222 tls_cert_subject(void * cert, uschar * mod)
 223 {
 224 uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert));
 225 return mod ? tls_field_from_dn(cp, mod) : cp;
 226 }
 227
 228 uschar *
 229 tls_cert_version(void * cert, uschar * mod)
 230 {
 231 return string_sprintf("%d", X509_get_version((X509 *)cert));
 232 }
 233
 234 uschar *
 235 tls_cert_ext_by_oid(void * cert, uschar * oid, int idx)
 236 {
 237 int nid = OBJ_create(CS oid, "", "");
 238 int nidx = X509_get_ext_by_NID((X509 *)cert, nid, idx);
 239 X509_EXTENSION * ex = X509_get_ext((X509 *)cert, nidx);
 240 ASN1_OCTET_STRING * adata = X509_EXTENSION_get_data(ex);
 241 BIO * bp = BIO_new(BIO_s_mem());
 242 long len;
 243 uschar * cp1;
 244 uschar * cp2;
 245 uschar * cp3;
 246
 247 if (!bp) return badalloc();
 248
 249 M_ASN1_OCTET_STRING_print(bp, adata);
 250 /* binary data, DER encoded */
 251
 252 /* just dump for now */
 253 len = BIO_get_mem_data(bp, &cp1);
 254 cp3 = cp2 = store_get(len*3+1);
 255
 256 while(len)
 257   {
 258   sprintf(CS cp2, "%.2x ", *cp1++);
 259   cp2 += 3;
 260   len--;
 261   }
 262 cp2[-1] = '\0';
 263
 264 return cp3;
 265 }
 266
 267 uschar *
 268 tls_cert_subject_altname(void * cert, uschar * mod)
 269 {
 270 uschar * list = NULL;
 271 STACK_OF(GENERAL_NAME) * san = (STACK_OF(GENERAL_NAME) *)
 272   X509_get_ext_d2i((X509 *)cert, NID_subject_alt_name, NULL, NULL);
 273 uschar sep = '\n';
 274 uschar * tag = US"";
 275 uschar * ele;
 276 int match = -1;
 277 int len;
 278
 279 if (!san) return NULL;
 280
 281 while (mod)
 282   {
 283   if (*mod == '>' && *++mod) sep = *mod++;
 284   else if (Ustrcmp(mod, "dns")==0) { match = GEN_DNS; mod += 3; }
 285   else if (Ustrcmp(mod, "uri")==0) { match = GEN_URI; mod += 3; }
 286   else if (Ustrcmp(mod, "mail")==0) { match = GEN_EMAIL; mod += 4; }
 287   else continue;
 288
 289   if (*mod++ != ',')
 290     break;
 291   }
 292
 293 while (sk_GENERAL_NAME_num(san) > 0)
 294   {
 295   GENERAL_NAME * namePart = sk_GENERAL_NAME_pop(san);
 296   if (match != -1 && match != namePart->type)
 297     continue;
 298   switch (namePart->type)
 299     {
 300     case GEN_DNS:
 301       tag = US"DNS";
 302       ele = ASN1_STRING_data(namePart->d.dNSName);
 303       len = ASN1_STRING_length(namePart->d.dNSName);
 304       break;
 305     case GEN_URI:
 306       tag = US"URI";
 307       ele = ASN1_STRING_data(namePart->d.uniformResourceIdentifier);
 308       len = ASN1_STRING_length(namePart->d.uniformResourceIdentifier);
 309       break;
 310     case GEN_EMAIL:
 311       tag = US"MAIL";
 312       ele = ASN1_STRING_data(namePart->d.rfc822Name);
 313       len = ASN1_STRING_length(namePart->d.rfc822Name);
 314       break;
 315     default:
 316       continue; /* ignore unrecognised types */
 317     }
 318   if (ele[len]) /* not nul-terminated */
 319     ele = string_copyn(ele, len);
 320
 321   if (strnlen(CS ele, len) == len)      /* ignore any with embedded nul */
 322     list = string_append_listele(list, sep,
 323           match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
 324   }
 325
 326 sk_GENERAL_NAME_free(san);
 327 return list;
 328 }
 329
 330 uschar *
 331 tls_cert_ocsp_uri(void * cert, uschar * mod)
 332 {
 333 STACK_OF(ACCESS_DESCRIPTION) * ads = (STACK_OF(ACCESS_DESCRIPTION) *)
 334   X509_get_ext_d2i((X509 *)cert, NID_info_access, NULL, NULL);
 335 int adsnum = sk_ACCESS_DESCRIPTION_num(ads);
 336 int i;
 337 uschar sep = '\n';
 338 uschar * list = NULL;
 339
 340 if (mod)
 341   if (*mod == '>' && *++mod) sep = *mod++;
 342
 343 for (i = 0; i < adsnum; i++)
 344   {
 345   ACCESS_DESCRIPTION * ad = sk_ACCESS_DESCRIPTION_value(ads, i);
 346
 347   if (ad && OBJ_obj2nid(ad->method) == NID_ad_OCSP)
 348     list = string_append_listele(list, sep,
 349               ASN1_STRING_data(ad->location->d.ia5));
 350   }
 351 return list;
 352 }
 353
 354 uschar *
 355 tls_cert_crl_uri(void * cert, uschar * mod)
 356 {
 357 STACK_OF(DIST_POINT) * dps = (STACK_OF(DIST_POINT) *)
 358   X509_get_ext_d2i((X509 *)cert,  NID_crl_distribution_points,
 359     NULL, NULL);
 360 DIST_POINT * dp;
 361 int dpsnum = sk_DIST_POINT_num(dps);
 362 int i;
 363 uschar sep = '\n';
 364 uschar * list = NULL;
 365
 366 if (mod)
 367   if (*mod == '>' && *++mod) sep = *mod++;
 368
 369 if (dps) for (i = 0; i < dpsnum; i++)
 370   if ((dp = sk_DIST_POINT_value(dps, i)))
 371     {
 372     STACK_OF(GENERAL_NAME) * names = dp->distpoint->name.fullname;
 373     GENERAL_NAME * np;
 374     int nnum = sk_GENERAL_NAME_num(names);
 375     int j;
 376
 377     for (j = 0; j < nnum; j++)
 378       if (  (np = sk_GENERAL_NAME_value(names, j))
 379          && np->type == GEN_URI
 380          )
 381         list = string_append_listele(list, sep,
 382                 ASN1_STRING_data(np->d.uniformResourceIdentifier));
 383     }
 384 return list;
 385 }
 386
 387
 388
 389 /*****************************************************
 390 *  Certificate operator routines
 391 *****************************************************/
 392 static uschar *
 393 fingerprint(X509 * cert, const EVP_MD * fdig)
 394 {
 395 int j;
 396 unsigned int n;
 397 uschar md[EVP_MAX_MD_SIZE];
 398 uschar * cp;
 399
 400 if (!X509_digest(cert,fdig,md,&n))
 401   {
 402   expand_string_message = US"tls_cert_fprt: out of mem\n";
 403   return NULL;
 404   }
 405 cp = store_get(n*2+1);
 406 for (j = 0; j < (int)n; j++) sprintf(CS cp+2*j, "%02X", md[j]);
 407 return(cp);
 408 }
 409
 410 uschar *
 411 tls_cert_fprt_md5(void * cert)
 412 {
 413 return fingerprint((X509 *)cert, EVP_md5());
 414 }
 415
 416 uschar *
 417 tls_cert_fprt_sha1(void * cert)
 418 {
 419 return fingerprint((X509 *)cert, EVP_sha1());
 420 }
 421
 422 uschar *
 423 tls_cert_fprt_sha256(void * cert)
 424 {
 425 return fingerprint((X509 *)cert, EVP_sha256());
 426 }
 427
 428
 429 /* vi: aw ai sw=2
 430 */
 431 /* End of tlscert-openssl.c */