crypto/external/bsd/heimdal/dist/kdc/kx509.c

   1 /*      $NetBSD: kx509.c,v 1.1.1.2 2014/04/24 12:45:27 pettai Exp $     */
   2
   3 /*
   4  * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
   5  * (Royal Institute of Technology, Stockholm, Sweden).
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "kdc_locl.h"
  37 #include <krb5/hex.h>
  38 #include <krb5/rfc2459_asn1.h>
  39 #include <krb5/hx509.h>
  40
  41 #ifdef KX509
  42
  43 /*
  44  *
  45  */
  46
  47 krb5_error_code
  48 _kdc_try_kx509_request(void *ptr, size_t len, struct Kx509Request *req, size_t *size)
  49 {
  50     if (len < 4)
  51         return -1;
  52     if (memcmp("\x00\x00\x02\x00", ptr, 4) != 0)
  53         return -1;
  54     return decode_Kx509Request(((unsigned char *)ptr) + 4, len - 4, req, size);
  55 }
  56
  57 /*
  58  *
  59  */
  60
  61 static const unsigned char version_2_0[4] = {0 , 0, 2, 0};
  62
  63 static krb5_error_code
  64 verify_req_hash(krb5_context context,
  65                 const Kx509Request *req,
  66                 krb5_keyblock *key)
  67 {
  68     unsigned char digest[SHA_DIGEST_LENGTH];
  69     HMAC_CTX ctx;
  70
  71     if (req->pk_hash.length != sizeof(digest)) {
  72         krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
  73                                "pk-hash have wrong length: %lu",
  74                                (unsigned long)req->pk_hash.length);
  75         return KRB5KDC_ERR_PREAUTH_FAILED;
  76     }
  77
  78     HMAC_CTX_init(&ctx);
  79     HMAC_Init_ex(&ctx,
  80                  key->keyvalue.data, key->keyvalue.length,
  81                  EVP_sha1(), NULL);
  82     if (sizeof(digest) != HMAC_size(&ctx))
  83         krb5_abortx(context, "runtime error, hmac buffer wrong size in kx509");
  84     HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
  85     HMAC_Update(&ctx, req->pk_key.data, req->pk_key.length);
  86     HMAC_Final(&ctx, digest, 0);
  87     HMAC_CTX_cleanup(&ctx);
  88
  89     if (memcmp(req->pk_hash.data, digest, sizeof(digest)) != 0) {
  90         krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
  91                                "pk-hash is not correct");
  92         return KRB5KDC_ERR_PREAUTH_FAILED;
  93     }
  94     return 0;
  95 }
  96
  97 static krb5_error_code
  98 calculate_reply_hash(krb5_context context,
  99                      krb5_keyblock *key,
 100                      Kx509Response *rep)
 101 {
 102     krb5_error_code ret;
 103     HMAC_CTX ctx;
 104
 105     HMAC_CTX_init(&ctx);
 106
 107     HMAC_Init_ex(&ctx, key->keyvalue.data, key->keyvalue.length,
 108                  EVP_sha1(), NULL);
 109     ret = krb5_data_alloc(rep->hash, HMAC_size(&ctx));
 110     if (ret) {
 111         HMAC_CTX_cleanup(&ctx);
 112         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 113         return ENOMEM;
 114     }
 115
 116     HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
 117     if (rep->error_code) {
 118         int32_t t = *rep->error_code;
 119         do {
 120             unsigned char p = (t & 0xff);
 121             HMAC_Update(&ctx, &p, 1);
 122             t >>= 8;
 123         } while (t);
 124     }
 125     if (rep->certificate)
 126         HMAC_Update(&ctx, rep->certificate->data, rep->certificate->length);
 127     if (rep->e_text)
 128         HMAC_Update(&ctx, (unsigned char *)*rep->e_text, strlen(*rep->e_text));
 129
 130     HMAC_Final(&ctx, rep->hash->data, 0);
 131     HMAC_CTX_cleanup(&ctx);
 132
 133     return 0;
 134 }
 135
 136 /*
 137  * Build a certifate for `principal´ that will expire at `endtime´.
 138  */
 139
 140 static krb5_error_code
 141 build_certificate(krb5_context context,
 142                   krb5_kdc_configuration *config,
 143                   const krb5_data *key,
 144                   time_t endtime,
 145                   krb5_principal principal,
 146                   krb5_data *certificate)
 147 {
 148     hx509_ca_tbs tbs = NULL;
 149     hx509_env env = NULL;
 150     hx509_cert cert = NULL;
 151     hx509_cert signer = NULL;
 152     int ret;
 153
 154     if (krb5_principal_get_comp_string(context, principal, 1) != NULL) {
 155         kdc_log(context, config, 0, "Principal is not a user");
 156         return EINVAL;
 157     }
 158
 159     ret = hx509_env_add(context->hx509ctx, &env, "principal-name",
 160                         krb5_principal_get_comp_string(context, principal, 0));
 161     if (ret)
 162         goto out;
 163
 164     {
 165         hx509_certs certs;
 166         hx509_query *q;
 167
 168         ret = hx509_certs_init(context->hx509ctx, config->kx509_ca, 0,
 169                                NULL, &certs);
 170         if (ret) {
 171             kdc_log(context, config, 0, "Failed to load CA %s",
 172                     config->kx509_ca);
 173             goto out;
 174         }
 175         ret = hx509_query_alloc(context->hx509ctx, &q);
 176         if (ret) {
 177             hx509_certs_free(&certs);
 178             goto out;
 179         }
 180
 181         hx509_query_match_option(q, HX509_QUERY_OPTION_PRIVATE_KEY);
 182         hx509_query_match_option(q, HX509_QUERY_OPTION_KU_KEYCERTSIGN);
 183
 184         ret = hx509_certs_find(context->hx509ctx, certs, q, &signer);
 185         hx509_query_free(context->hx509ctx, q);
 186         hx509_certs_free(&certs);
 187         if (ret) {
 188             kdc_log(context, config, 0, "Failed to find a CA in %s",
 189                     config->kx509_ca);
 190             goto out;
 191         }
 192     }
 193
 194     ret = hx509_ca_tbs_init(context->hx509ctx, &tbs);
 195     if (ret)
 196         goto out;
 197
 198     {
 199         SubjectPublicKeyInfo spki;
 200         heim_any any;
 201
 202         memset(&spki, 0, sizeof(spki));
 203
 204         spki.subjectPublicKey.data = key->data;
 205         spki.subjectPublicKey.length = key->length * 8;
 206
 207         ret = der_copy_oid(&asn1_oid_id_pkcs1_rsaEncryption,
 208                            &spki.algorithm.algorithm);
 209
 210         any.data = "\x05\x00";
 211         any.length = 2;
 212         spki.algorithm.parameters = &any;
 213
 214         ret = hx509_ca_tbs_set_spki(context->hx509ctx, tbs, &spki);
 215         der_free_oid(&spki.algorithm.algorithm);
 216         if (ret)
 217             goto out;
 218     }
 219
 220     {
 221         hx509_certs certs;
 222         hx509_cert template;
 223
 224         ret = hx509_certs_init(context->hx509ctx, config->kx509_template, 0,
 225                                NULL, &certs);
 226         if (ret) {
 227             kdc_log(context, config, 0, "Failed to load template %s",
 228                     config->kx509_template);
 229             goto out;
 230         }
 231         ret = hx509_get_one_cert(context->hx509ctx, certs, &template);
 232         hx509_certs_free(&certs);
 233         if (ret) {
 234             kdc_log(context, config, 0, "Failed to find template in %s",
 235                     config->kx509_template);
 236             goto out;
 237         }
 238         ret = hx509_ca_tbs_set_template(context->hx509ctx, tbs,
 239                                         HX509_CA_TEMPLATE_SUBJECT|
 240                                         HX509_CA_TEMPLATE_KU|
 241                                         HX509_CA_TEMPLATE_EKU,
 242                                         template);
 243         hx509_cert_free(template);
 244         if (ret)
 245             goto out;
 246     }
 247
 248     hx509_ca_tbs_set_notAfter(context->hx509ctx, tbs, endtime);
 249
 250     hx509_ca_tbs_subject_expand(context->hx509ctx, tbs, env);
 251     hx509_env_free(&env);
 252
 253     ret = hx509_ca_sign(context->hx509ctx, tbs, signer, &cert);
 254     hx509_cert_free(signer);
 255     if (ret)
 256         goto out;
 257
 258     hx509_ca_tbs_free(&tbs);
 259
 260     ret = hx509_cert_binary(context->hx509ctx, cert, certificate);
 261     hx509_cert_free(cert);
 262     if (ret)
 263         goto out;
 264
 265     return 0;
 266 out:
 267     if (env)
 268         hx509_env_free(&env);
 269     if (tbs)
 270         hx509_ca_tbs_free(&tbs);
 271     if (signer)
 272         hx509_cert_free(signer);
 273     krb5_set_error_message(context, ret, "cert creation failed");
 274     return ret;
 275 }
 276
 277 /*
 278  *
 279  */
 280
 281 krb5_error_code
 282 _kdc_do_kx509(krb5_context context,
 283               krb5_kdc_configuration *config,
 284               const struct Kx509Request *req, krb5_data *reply,
 285               const char *from, struct sockaddr *addr)
 286 {
 287     krb5_error_code ret;
 288     krb5_ticket *ticket = NULL;
 289     krb5_flags ap_req_options;
 290     krb5_auth_context ac = NULL;
 291     krb5_keytab id = NULL;
 292     krb5_principal sprincipal = NULL, cprincipal = NULL;
 293     char *cname = NULL;
 294     Kx509Response rep;
 295     size_t size;
 296     krb5_keyblock *key = NULL;
 297
 298     krb5_data_zero(reply);
 299     memset(&rep, 0, sizeof(rep));
 300
 301     if(!config->enable_kx509) {
 302         kdc_log(context, config, 0,
 303                 "Rejected kx509 request (disabled) from %s", from);
 304         return KRB5KDC_ERR_POLICY;
 305     }
 306
 307     kdc_log(context, config, 0, "Kx509 request from %s", from);
 308
 309     ret = krb5_kt_resolve(context, "HDB:", &id);
 310     if (ret) {
 311         kdc_log(context, config, 0, "Can't open database for digest");
 312         goto out;
 313     }
 314
 315     ret = krb5_rd_req(context,
 316                       &ac,
 317                       &req->authenticator,
 318                       NULL,
 319                       id,
 320                       &ap_req_options,
 321                       &ticket);
 322     if (ret)
 323         goto out;
 324
 325     ret = krb5_ticket_get_client(context, ticket, &cprincipal);
 326     if (ret)
 327         goto out;
 328
 329     ret = krb5_unparse_name(context, cprincipal, &cname);
 330     if (ret)
 331         goto out;
 332
 333     /* verify server principal */
 334
 335     ret = krb5_sname_to_principal(context, NULL, "kca_service",
 336                                   KRB5_NT_UNKNOWN, &sprincipal);
 337     if (ret)
 338         goto out;
 339
 340     {
 341         krb5_principal principal = NULL;
 342
 343         ret = krb5_ticket_get_server(context, ticket, &principal);
 344         if (ret)
 345             goto out;
 346
 347         ret = krb5_principal_compare(context, sprincipal, principal);
 348         krb5_free_principal(context, principal);
 349         if (ret != TRUE) {
 350             char *expected, *used;
 351
 352             ret = krb5_unparse_name(context, sprincipal, &expected);
 353             if (ret)
 354                 goto out;
 355             ret = krb5_unparse_name(context, principal, &used);
 356             if (ret) {
 357                 krb5_xfree(expected);
 358                 goto out;
 359             }
 360
 361             ret = KRB5KDC_ERR_SERVER_NOMATCH;
 362             krb5_set_error_message(context, ret,
 363                                    "User %s used wrong Kx509 service "
 364                                    "principal, expected: %s, used %s",
 365                                    cname, expected, used);
 366             krb5_xfree(expected);
 367             krb5_xfree(used);
 368             goto out;
 369         }
 370     }
 371
 372     ret = krb5_auth_con_getkey(context, ac, &key);
 373     if (ret == 0 && key == NULL)
 374         ret = KRB5KDC_ERR_NULL_KEY;
 375     if (ret) {
 376         krb5_set_error_message(context, ret, "Kx509 can't get session key");
 377         goto out;
 378     }
 379
 380     ret = verify_req_hash(context, req, key);
 381     if (ret)
 382         goto out;
 383
 384     /* Verify that the key is encoded RSA key */
 385     {
 386         RSAPublicKey key;
 387         size_t size;
 388
 389         ret = decode_RSAPublicKey(req->pk_key.data, req->pk_key.length,
 390                                   &key, &size);
 391         if (ret)
 392             goto out;
 393         free_RSAPublicKey(&key);
 394         if (size != req->pk_key.length) {
 395             ret = ASN1_EXTRA_DATA;
 396             goto out;
 397         }
 398     }
 399
 400     ALLOC(rep.certificate);
 401     if (rep.certificate == NULL)
 402         goto out;
 403     krb5_data_zero(rep.certificate);
 404     ALLOC(rep.hash);
 405     if (rep.hash == NULL)
 406         goto out;
 407     krb5_data_zero(rep.hash);
 408
 409     ret = build_certificate(context, config, &req->pk_key,
 410                             krb5_ticket_get_endtime(context, ticket),
 411                             cprincipal, rep.certificate);
 412     if (ret)
 413         goto out;
 414
 415     ret = calculate_reply_hash(context, key, &rep);
 416     if (ret)
 417         goto out;
 418
 419     /*
 420      * Encode reply, [ version | Kx509Response ]
 421      */
 422
 423     {
 424         krb5_data data;
 425
 426         ASN1_MALLOC_ENCODE(Kx509Response, data.data, data.length, &rep,
 427                            &size, ret);
 428         if (ret) {
 429             krb5_set_error_message(context, ret, "Failed to encode kx509 reply");
 430             goto out;
 431         }
 432         if (size != data.length)
 433             krb5_abortx(context, "ASN1 internal error");
 434
 435         ret = krb5_data_alloc(reply, data.length + sizeof(version_2_0));
 436         if (ret) {
 437             free(data.data);
 438             goto out;
 439         }
 440         memcpy(reply->data, version_2_0, sizeof(version_2_0));
 441         memcpy(((unsigned char *)reply->data) + sizeof(version_2_0),
 442                data.data, data.length);
 443         free(data.data);
 444     }
 445
 446     kdc_log(context, config, 0, "Successful Kx509 request for %s", cname);
 447
 448 out:
 449     if (ac)
 450         krb5_auth_con_free(context, ac);
 451     if (ret)
 452         krb5_warn(context, ret, "Kx509 request from %s failed", from);
 453     if (ticket)
 454         krb5_free_ticket(context, ticket);
 455     if (id)
 456         krb5_kt_close(context, id);
 457     if (sprincipal)
 458         krb5_free_principal(context, sprincipal);
 459     if (cprincipal)
 460         krb5_free_principal(context, cprincipal);
 461     if (key)
 462         krb5_free_keyblock (context, key);
 463     if (cname)
 464         free(cname);
 465     free_Kx509Response(&rep);
 466
 467     return 0;
 468 }
 469
 470 #endif /* KX509 */