source3/libads/krb5_setpw.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    krb5 set password implementation
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Remus Koos 2001 (remuskoos@yahoo.com)
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "smb_krb5.h"
  23 #include "libads/kerberos_proto.h"
  24 #include "../lib/util/asn1.h"
  25
  26 #ifdef HAVE_KRB5
  27
  28 #define DEFAULT_KPASSWD_PORT    464
  29
  30 #define KRB5_KPASSWD_VERS_CHANGEPW              1
  31
  32 #define KRB5_KPASSWD_VERS_SETPW                 0xff80
  33 #define KRB5_KPASSWD_VERS_SETPW_ALT             2
  34
  35 #define KRB5_KPASSWD_SUCCESS                    0
  36 #define KRB5_KPASSWD_MALFORMED                  1
  37 #define KRB5_KPASSWD_HARDERROR                  2
  38 #define KRB5_KPASSWD_AUTHERROR                  3
  39 #define KRB5_KPASSWD_SOFTERROR                  4
  40 #define KRB5_KPASSWD_ACCESSDENIED               5
  41 #define KRB5_KPASSWD_BAD_VERSION                6
  42 #define KRB5_KPASSWD_INITIAL_FLAG_NEEDED        7
  43
  44 /* Those are defined by kerberos-set-passwd-02.txt and are probably
  45  * not supported by M$ implementation */
  46 #define KRB5_KPASSWD_POLICY_REJECT              8
  47 #define KRB5_KPASSWD_BAD_PRINCIPAL              9
  48 #define KRB5_KPASSWD_ETYPE_NOSUPP               10
  49
  50 /*
  51  * we've got to be able to distinguish KRB_ERRORs from other
  52  * requests - valid response for CHPW v2 replies.
  53  */
  54
  55 #define krb5_is_krb_error(packet) \
  56         ( packet && packet->length && (((char *)packet->data)[0] == 0x7e || ((char *)packet->data)[0] == 0x5e))
  57
  58 /* This implements kerberos password change protocol as specified in
  59  * kerb-chg-password-02.txt and kerberos-set-passwd-02.txt
  60  * as well as microsoft version of the protocol
  61  * as specified in kerberos-set-passwd-00.txt
  62  */
  63 static DATA_BLOB encode_krb5_setpw(const char *principal, const char *password)
  64 {
  65         char* princ_part1 = NULL;
  66         char* princ_part2 = NULL;
  67         char* realm = NULL;
  68         char* c;
  69         char* princ;
  70
  71         ASN1_DATA *req;
  72         DATA_BLOB ret;
  73
  74
  75         princ = SMB_STRDUP(principal);
  76
  77         if ((c = strchr_m(princ, '/')) == NULL) {
  78                 c = princ;
  79         } else {
  80                 *c = '\0';
  81                 c++;
  82                 princ_part1 = princ;
  83         }
  84
  85         princ_part2 = c;
  86
  87         if ((c = strchr_m(c, '@')) != NULL) {
  88                 *c = '\0';
  89                 c++;
  90                 realm = c;
  91         } else {
  92                 /* We must have a realm component. */
  93                 return data_blob_null;
  94         }
  95
  96         req = asn1_init(talloc_tos());
  97         if (req == NULL) {
  98                 return data_blob_null;
  99         }
 100
 101         asn1_push_tag(req, ASN1_SEQUENCE(0));
 102         asn1_push_tag(req, ASN1_CONTEXT(0));
 103         asn1_write_OctetString(req, password, strlen(password));
 104         asn1_pop_tag(req);
 105
 106         asn1_push_tag(req, ASN1_CONTEXT(1));
 107         asn1_push_tag(req, ASN1_SEQUENCE(0));
 108
 109         asn1_push_tag(req, ASN1_CONTEXT(0));
 110         asn1_write_Integer(req, 1);
 111         asn1_pop_tag(req);
 112
 113         asn1_push_tag(req, ASN1_CONTEXT(1));
 114         asn1_push_tag(req, ASN1_SEQUENCE(0));
 115
 116         if (princ_part1) {
 117                 asn1_write_GeneralString(req, princ_part1);
 118         }
 119
 120         asn1_write_GeneralString(req, princ_part2);
 121         asn1_pop_tag(req);
 122         asn1_pop_tag(req);
 123         asn1_pop_tag(req);
 124         asn1_pop_tag(req);
 125
 126         asn1_push_tag(req, ASN1_CONTEXT(2));
 127         asn1_write_GeneralString(req, realm);
 128         asn1_pop_tag(req);
 129         asn1_pop_tag(req);
 130
 131         ret = data_blob(req->data, req->length);
 132         asn1_free(req);
 133
 134         free(princ);
 135
 136         return ret;
 137 }
 138
 139 static krb5_error_code build_kpasswd_request(uint16 pversion,
 140                                            krb5_context context,
 141                                            krb5_auth_context auth_context,
 142                                            krb5_data *ap_req,
 143                                            const char *princ,
 144                                            const char *passwd,
 145                                            bool use_tcp,
 146                                            krb5_data *packet)
 147 {
 148         krb5_error_code ret;
 149         krb5_data cipherpw;
 150         krb5_data encoded_setpw;
 151         krb5_replay_data replay;
 152         char *p, *msg_start;
 153         DATA_BLOB setpw;
 154         unsigned int msg_length;
 155
 156         ret = krb5_auth_con_setflags(context,
 157                                      auth_context,KRB5_AUTH_CONTEXT_DO_SEQUENCE);
 158         if (ret) {
 159                 DEBUG(1,("krb5_auth_con_setflags failed (%s)\n",
 160                          error_message(ret)));
 161                 return ret;
 162         }
 163
 164         /* handle protocol differences in chpw and setpw */
 165         if (pversion  == KRB5_KPASSWD_VERS_CHANGEPW)
 166                 setpw = data_blob(passwd, strlen(passwd));
 167         else if (pversion == KRB5_KPASSWD_VERS_SETPW ||
 168                  pversion == KRB5_KPASSWD_VERS_SETPW_ALT)
 169                 setpw = encode_krb5_setpw(princ, passwd);
 170         else
 171                 return EINVAL;
 172
 173         if (setpw.data == NULL || setpw.length == 0) {
 174                 return EINVAL;
 175         }
 176
 177         encoded_setpw.data = (char *)setpw.data;
 178         encoded_setpw.length = setpw.length;
 179
 180         ret = krb5_mk_priv(context, auth_context,
 181                            &encoded_setpw, &cipherpw, &replay);
 182
 183         data_blob_free(&setpw);         /*from 'encode_krb5_setpw(...)' */
 184
 185         if (ret) {
 186                 DEBUG(1,("krb5_mk_priv failed (%s)\n", error_message(ret)));
 187                 return ret;
 188         }
 189
 190         packet->data = (char *)SMB_MALLOC(ap_req->length + cipherpw.length + (use_tcp ? 10 : 6 ));
 191         if (!packet->data)
 192                 return -1;
 193
 194
 195
 196         /* see the RFC for details */
 197
 198         msg_start = p = ((char *)packet->data) + (use_tcp ? 4 : 0);
 199         p += 2;
 200         RSSVAL(p, 0, pversion);
 201         p += 2;
 202         RSSVAL(p, 0, ap_req->length);
 203         p += 2;
 204         memcpy(p, ap_req->data, ap_req->length);
 205         p += ap_req->length;
 206         memcpy(p, cipherpw.data, cipherpw.length);
 207         p += cipherpw.length;
 208         packet->length = PTR_DIFF(p,packet->data);
 209         msg_length = PTR_DIFF(p,msg_start);
 210
 211         if (use_tcp) {
 212                 RSIVAL(packet->data, 0, msg_length);
 213         }
 214         RSSVAL(msg_start, 0, msg_length);
 215
 216         free(cipherpw.data);    /* from 'krb5_mk_priv(...)' */
 217
 218         return 0;
 219 }
 220
 221 static const struct kpasswd_errors {
 222         int result_code;
 223         const char *error_string;
 224 } kpasswd_errors[] = {
 225         {KRB5_KPASSWD_MALFORMED, "Malformed request error"},
 226         {KRB5_KPASSWD_HARDERROR, "Server error"},
 227         {KRB5_KPASSWD_AUTHERROR, "Authentication error"},
 228         {KRB5_KPASSWD_SOFTERROR, "Password change rejected"},
 229         {KRB5_KPASSWD_ACCESSDENIED, "Client does not have proper authorization"},
 230         {KRB5_KPASSWD_BAD_VERSION, "Protocol version not supported"},
 231         {KRB5_KPASSWD_INITIAL_FLAG_NEEDED, "Authorization ticket must have initial flag set"},
 232         {KRB5_KPASSWD_POLICY_REJECT, "Password rejected due to policy requirements"},
 233         {KRB5_KPASSWD_BAD_PRINCIPAL, "Target principal does not exist"},
 234         {KRB5_KPASSWD_ETYPE_NOSUPP, "Unsupported encryption type"},
 235         {0, NULL}
 236 };
 237
 238 static krb5_error_code setpw_result_code_string(krb5_context context,
 239                                                 int result_code,
 240                                                 const char **code_string)
 241 {
 242         unsigned int idx = 0;
 243
 244         while (kpasswd_errors[idx].error_string != NULL) {
 245                 if (kpasswd_errors[idx].result_code ==
 246                     result_code) {
 247                         *code_string = kpasswd_errors[idx].error_string;
 248                         return 0;
 249                 }
 250                 idx++;
 251         }
 252         *code_string = "Password change failed";
 253         return (0);
 254 }
 255
 256  krb5_error_code kpasswd_err_to_krb5_err(krb5_error_code res_code)
 257 {
 258         switch(res_code) {
 259                 case KRB5_KPASSWD_ACCESSDENIED:
 260                         return KRB5KDC_ERR_BADOPTION;
 261                 case KRB5_KPASSWD_INITIAL_FLAG_NEEDED:
 262                         return KRB5KDC_ERR_BADOPTION;
 263                         /* return KV5M_ALT_METHOD; MIT-only define */
 264                 case KRB5_KPASSWD_ETYPE_NOSUPP:
 265                         return KRB5KDC_ERR_ETYPE_NOSUPP;
 266                 case KRB5_KPASSWD_BAD_PRINCIPAL:
 267                         return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
 268                 case KRB5_KPASSWD_POLICY_REJECT:
 269                 case KRB5_KPASSWD_SOFTERROR:
 270                         return KRB5KDC_ERR_POLICY;
 271                 default:
 272                         return KRB5KRB_ERR_GENERIC;
 273         }
 274 }
 275 static krb5_error_code parse_setpw_reply(krb5_context context,
 276                                          bool use_tcp,
 277                                          krb5_auth_context auth_context,
 278                                          krb5_data *packet)
 279 {
 280         krb5_data ap_rep;
 281         char *p;
 282         int vnum, ret, res_code;
 283         krb5_data cipherresult;
 284         krb5_data clearresult;
 285         krb5_ap_rep_enc_part *ap_rep_enc;
 286         krb5_replay_data replay;
 287         unsigned int msg_length = packet->length;
 288
 289
 290         if (packet->length < (use_tcp ? 8 : 4)) {
 291                 return KRB5KRB_AP_ERR_MODIFIED;
 292         }
 293
 294         p = (char *)packet->data;
 295         /*
 296         ** see if it is an error
 297         */
 298         if (krb5_is_krb_error(packet)) {
 299
 300                 ret = handle_krberror_packet(context, packet);
 301                 if (ret) {
 302                         return ret;
 303                 }
 304         }
 305
 306
 307         /* tcp... */
 308         if (use_tcp) {
 309                 msg_length -= 4;
 310                 if (RIVAL(p, 0) != msg_length) {
 311                         DEBUG(1,("Bad TCP packet length (%d/%d) from kpasswd server\n",
 312                         RIVAL(p, 0), msg_length));
 313                         return KRB5KRB_AP_ERR_MODIFIED;
 314                 }
 315
 316                 p += 4;
 317         }
 318
 319         if (RSVAL(p, 0) != msg_length) {
 320                 DEBUG(1,("Bad packet length (%d/%d) from kpasswd server\n",
 321                          RSVAL(p, 0), msg_length));
 322                 return KRB5KRB_AP_ERR_MODIFIED;
 323         }
 324
 325         p += 2;
 326
 327         vnum = RSVAL(p, 0); p += 2;
 328
 329         /* FIXME: According to standard there is only one type of reply */
 330         if (vnum != KRB5_KPASSWD_VERS_SETPW &&
 331             vnum != KRB5_KPASSWD_VERS_SETPW_ALT &&
 332             vnum != KRB5_KPASSWD_VERS_CHANGEPW) {
 333                 DEBUG(1,("Bad vnum (%d) from kpasswd server\n", vnum));
 334                 return KRB5KDC_ERR_BAD_PVNO;
 335         }
 336
 337         ap_rep.length = RSVAL(p, 0); p += 2;
 338
 339         if (p + ap_rep.length >= (char *)packet->data + packet->length) {
 340                 DEBUG(1,("ptr beyond end of packet from kpasswd server\n"));
 341                 return KRB5KRB_AP_ERR_MODIFIED;
 342         }
 343
 344         if (ap_rep.length == 0) {
 345                 DEBUG(1,("got unencrypted setpw result?!\n"));
 346                 return KRB5KRB_AP_ERR_MODIFIED;
 347         }
 348
 349         /* verify ap_rep */
 350         ap_rep.data = p;
 351         p += ap_rep.length;
 352
 353         ret = krb5_rd_rep(context, auth_context, &ap_rep, &ap_rep_enc);
 354         if (ret) {
 355                 DEBUG(1,("failed to rd setpw reply (%s)\n", error_message(ret)));
 356                 return KRB5KRB_AP_ERR_MODIFIED;
 357         }
 358
 359         krb5_free_ap_rep_enc_part(context, ap_rep_enc);
 360
 361         cipherresult.data = p;
 362         cipherresult.length = ((char *)packet->data + packet->length) - p;
 363
 364         ret = krb5_rd_priv(context, auth_context, &cipherresult, &clearresult,
 365                            &replay);
 366         if (ret) {
 367                 DEBUG(1,("failed to decrypt setpw reply (%s)\n", error_message(ret)));
 368                 return KRB5KRB_AP_ERR_MODIFIED;
 369         }
 370
 371         if (clearresult.length < 2) {
 372                 free(clearresult.data);
 373                 ret = KRB5KRB_AP_ERR_MODIFIED;
 374                 return KRB5KRB_AP_ERR_MODIFIED;
 375         }
 376
 377         p = (char *)clearresult.data;
 378
 379         res_code = RSVAL(p, 0);
 380
 381         free(clearresult.data);
 382
 383         if ((res_code < KRB5_KPASSWD_SUCCESS) ||
 384             (res_code > KRB5_KPASSWD_ETYPE_NOSUPP)) {
 385                 return KRB5KRB_AP_ERR_MODIFIED;
 386         }
 387
 388         if (res_code == KRB5_KPASSWD_SUCCESS) {
 389                 return 0;
 390         } else {
 391                 const char *errstr;
 392                 setpw_result_code_string(context, res_code, &errstr);
 393                 DEBUG(1, ("Error changing password: %s (%d)\n", errstr, res_code));
 394
 395                 return kpasswd_err_to_krb5_err(res_code);
 396         }
 397 }
 398
 399 static ADS_STATUS do_krb5_kpasswd_request(krb5_context context,
 400                                           const char *kdc_host,
 401                                           uint16 pversion,
 402                                           krb5_creds *credsp,
 403                                           const char *princ,
 404                                           const char *newpw)
 405 {
 406         krb5_auth_context auth_context = NULL;
 407         krb5_data ap_req, chpw_req, chpw_rep;
 408         int ret, sock;
 409         socklen_t addr_len;
 410         struct sockaddr_storage remote_addr, local_addr;
 411         struct sockaddr_storage addr;
 412         krb5_address local_kaddr, remote_kaddr;
 413         bool use_tcp = False;
 414
 415
 416         if (!interpret_string_addr(&addr, kdc_host, 0)) {
 417         }
 418
 419         ret = krb5_mk_req_extended(context, &auth_context, AP_OPTS_USE_SUBKEY,
 420                                    NULL, credsp, &ap_req);
 421         if (ret) {
 422                 DEBUG(1,("krb5_mk_req_extended failed (%s)\n", error_message(ret)));
 423                 return ADS_ERROR_KRB5(ret);
 424         }
 425
 426         do {
 427
 428                 if (!use_tcp) {
 429
 430                         sock = open_udp_socket(kdc_host, DEFAULT_KPASSWD_PORT);
 431                         if (sock == -1) {
 432                                 int rc = errno;
 433                                 SAFE_FREE(ap_req.data);
 434                                 krb5_auth_con_free(context, auth_context);
 435                                 DEBUG(1,("failed to open kpasswd socket to %s "
 436                                          "(%s)\n", kdc_host, strerror(errno)));
 437                                 return ADS_ERROR_SYSTEM(rc);
 438                         }
 439                 } else {
 440                         NTSTATUS status;
 441                         status = open_socket_out(&addr, DEFAULT_KPASSWD_PORT,
 442                                                  LONG_CONNECT_TIMEOUT, &sock);
 443                         if (!NT_STATUS_IS_OK(status)) {
 444                                 SAFE_FREE(ap_req.data);
 445                                 krb5_auth_con_free(context, auth_context);
 446                                 DEBUG(1,("failed to open kpasswd socket to %s "
 447                                          "(%s)\n", kdc_host,
 448                                          nt_errstr(status)));
 449                                 return ADS_ERROR_NT(status);
 450                         }
 451                 }
 452
 453                 addr_len = sizeof(remote_addr);
 454                 if (getpeername(sock, (struct sockaddr *)&remote_addr, &addr_len) != 0) {
 455                         close(sock);
 456                         SAFE_FREE(ap_req.data);
 457                         krb5_auth_con_free(context, auth_context);
 458                         DEBUG(1,("getpeername() failed (%s)\n", error_message(errno)));
 459                         return ADS_ERROR_SYSTEM(errno);
 460                 }
 461                 addr_len = sizeof(local_addr);
 462                 if (getsockname(sock, (struct sockaddr *)&local_addr, &addr_len) != 0) {
 463                         close(sock);
 464                         SAFE_FREE(ap_req.data);
 465                         krb5_auth_con_free(context, auth_context);
 466                         DEBUG(1,("getsockname() failed (%s)\n", error_message(errno)));
 467                         return ADS_ERROR_SYSTEM(errno);
 468                 }
 469                 if (!setup_kaddr(&remote_kaddr, &remote_addr) ||
 470                                 !setup_kaddr(&local_kaddr, &local_addr)) {
 471                         DEBUG(1,("do_krb5_kpasswd_request: "
 472                                 "Failed to setup addresses.\n"));
 473                         close(sock);
 474                         SAFE_FREE(ap_req.data);
 475                         krb5_auth_con_free(context, auth_context);
 476                         errno = EINVAL;
 477                         return ADS_ERROR_SYSTEM(EINVAL);
 478                 }
 479
 480                 ret = krb5_auth_con_setaddrs(context, auth_context, &local_kaddr, NULL);
 481                 if (ret) {
 482                         close(sock);
 483                         SAFE_FREE(ap_req.data);
 484                         krb5_auth_con_free(context, auth_context);
 485                         DEBUG(1,("krb5_auth_con_setaddrs failed (%s)\n", error_message(ret)));
 486                         return ADS_ERROR_KRB5(ret);
 487                 }
 488
 489                 ret = build_kpasswd_request(pversion, context, auth_context, &ap_req,
 490                                           princ, newpw, use_tcp, &chpw_req);
 491                 if (ret) {
 492                         close(sock);
 493                         SAFE_FREE(ap_req.data);
 494                         krb5_auth_con_free(context, auth_context);
 495                         DEBUG(1,("build_setpw_request failed (%s)\n", error_message(ret)));
 496                         return ADS_ERROR_KRB5(ret);
 497                 }
 498
 499                 ret = write(sock, chpw_req.data, chpw_req.length);
 500
 501                 if (ret != chpw_req.length) {
 502                         close(sock);
 503                         SAFE_FREE(chpw_req.data);
 504                         SAFE_FREE(ap_req.data);
 505                         krb5_auth_con_free(context, auth_context);
 506                         DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
 507                         return ADS_ERROR_SYSTEM(errno);
 508                 }
 509
 510                 SAFE_FREE(chpw_req.data);
 511
 512                 chpw_rep.length = 1500;
 513                 chpw_rep.data = (char *) SMB_MALLOC(chpw_rep.length);
 514                 if (!chpw_rep.data) {
 515                         close(sock);
 516                         SAFE_FREE(ap_req.data);
 517                         krb5_auth_con_free(context, auth_context);
 518                         DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
 519                         errno = ENOMEM;
 520                         return ADS_ERROR_SYSTEM(errno);
 521                 }
 522
 523                 ret = read(sock, chpw_rep.data, chpw_rep.length);
 524                 if (ret < 0) {
 525                         close(sock);
 526                         SAFE_FREE(chpw_rep.data);
 527                         SAFE_FREE(ap_req.data);
 528                         krb5_auth_con_free(context, auth_context);
 529                         DEBUG(1,("recv of chpw reply failed (%s)\n", strerror(errno)));
 530                         return ADS_ERROR_SYSTEM(errno);
 531                 }
 532
 533                 close(sock);
 534                 chpw_rep.length = ret;
 535
 536                 ret = krb5_auth_con_setaddrs(context, auth_context, NULL,&remote_kaddr);
 537                 if (ret) {
 538                         SAFE_FREE(chpw_rep.data);
 539                         SAFE_FREE(ap_req.data);
 540                         krb5_auth_con_free(context, auth_context);
 541                         DEBUG(1,("krb5_auth_con_setaddrs on reply failed (%s)\n",
 542                                  error_message(ret)));
 543                         return ADS_ERROR_KRB5(ret);
 544                 }
 545
 546                 ret = parse_setpw_reply(context, use_tcp, auth_context, &chpw_rep);
 547                 SAFE_FREE(chpw_rep.data);
 548
 549                 if (ret) {
 550
 551                         if (ret == KRB5KRB_ERR_RESPONSE_TOO_BIG && !use_tcp) {
 552                                 DEBUG(5, ("Trying setpw with TCP!!!\n"));
 553                                 use_tcp = True;
 554                                 continue;
 555                         }
 556
 557                         SAFE_FREE(ap_req.data);
 558                         krb5_auth_con_free(context, auth_context);
 559                         DEBUG(1,("parse_setpw_reply failed (%s)\n",
 560                                  error_message(ret)));
 561                         return ADS_ERROR_KRB5(ret);
 562                 }
 563
 564                 SAFE_FREE(ap_req.data);
 565                 krb5_auth_con_free(context, auth_context);
 566         } while ( ret );
 567
 568         return ADS_SUCCESS;
 569 }
 570
 571 ADS_STATUS ads_krb5_set_password(const char *kdc_host, const char *princ,
 572                                  const char *newpw, int time_offset)
 573 {
 574
 575         ADS_STATUS aret;
 576         krb5_error_code ret = 0;
 577         krb5_context context = NULL;
 578         const char *realm = NULL;
 579         unsigned int realm_len = 0;
 580         krb5_creds creds, *credsp = NULL;
 581         krb5_ccache ccache = NULL;
 582
 583         ZERO_STRUCT(creds);
 584
 585         initialize_krb5_error_table();
 586         ret = krb5_init_context(&context);
 587         if (ret) {
 588                 DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
 589                 return ADS_ERROR_KRB5(ret);
 590         }
 591
 592         if (time_offset != 0) {
 593                 krb5_set_real_time(context, time(NULL) + time_offset, 0);
 594         }
 595
 596         ret = krb5_cc_default(context, &ccache);
 597         if (ret) {
 598                 krb5_free_context(context);
 599                 DEBUG(1,("Failed to get default creds (%s)\n", error_message(ret)));
 600                 return ADS_ERROR_KRB5(ret);
 601         }
 602
 603         ret = krb5_cc_get_principal(context, ccache, &creds.client);
 604         if (ret) {
 605                 krb5_cc_close(context, ccache);
 606                 krb5_free_context(context);
 607                 DEBUG(1,("Failed to get principal from ccache (%s)\n",
 608                          error_message(ret)));
 609                 return ADS_ERROR_KRB5(ret);
 610         }
 611
 612         realm = smb_krb5_principal_get_realm(context, creds.client);
 613         realm_len = strlen(realm);
 614         ret = krb5_build_principal(context,
 615                                    &creds.server,
 616                                    realm_len,
 617                                    realm, "kadmin", "changepw", NULL);
 618
 619         ret = krb5_get_credentials(context, 0, ccache, &creds, &credsp);
 620         if (ret) {
 621                 krb5_cc_close(context, ccache);
 622                 krb5_free_principal(context, creds.client);
 623                 krb5_free_principal(context, creds.server);
 624                 krb5_free_context(context);
 625                 DEBUG(1,("krb5_build_prinipal_ext (%s)\n", error_message(ret)));
 626                 return ADS_ERROR_KRB5(ret);
 627         }
 628
 629         ret = krb5_get_credentials(context, 0, ccache, &creds, &credsp);
 630         if (ret) {
 631                 krb5_cc_close(context, ccache);
 632                 krb5_free_principal(context, creds.client);
 633                 krb5_free_principal(context, creds.server);
 634                 krb5_free_context(context);
 635                 DEBUG(1,("krb5_get_credentials failed (%s)\n", error_message(ret)));
 636                 return ADS_ERROR_KRB5(ret);
 637         }
 638
 639         /* we might have to call krb5_free_creds(...) from now on ... */
 640
 641         aret = do_krb5_kpasswd_request(context, kdc_host,
 642                                        KRB5_KPASSWD_VERS_SETPW,
 643                                        credsp, princ, newpw);
 644
 645         krb5_free_creds(context, credsp);
 646         krb5_free_principal(context, creds.client);
 647         krb5_free_principal(context, creds.server);
 648         krb5_cc_close(context, ccache);
 649         krb5_free_context(context);
 650
 651         return aret;
 652 }
 653
 654 /*
 655   we use a prompter to avoid a crash bug in the kerberos libs when
 656   dealing with empty passwords
 657   this prompter is just a string copy ...
 658 */
 659 static krb5_error_code
 660 kerb_prompter(krb5_context ctx, void *data,
 661                const char *name,
 662                const char *banner,
 663                int num_prompts,
 664                krb5_prompt prompts[])
 665 {
 666         if (num_prompts == 0) return 0;
 667
 668         memset(prompts[0].reply->data, 0, prompts[0].reply->length);
 669         if (prompts[0].reply->length > 0) {
 670                 if (data) {
 671                         strncpy((char *)prompts[0].reply->data,
 672                                 (const char *)data,
 673                                 prompts[0].reply->length-1);
 674                         prompts[0].reply->length = strlen((const char *)prompts[0].reply->data);
 675                 } else {
 676                         prompts[0].reply->length = 0;
 677                 }
 678         }
 679         return 0;
 680 }
 681
 682 static ADS_STATUS ads_krb5_chg_password(const char *kdc_host,
 683                                         const char *principal,
 684                                         const char *oldpw,
 685                                         const char *newpw,
 686                                         int time_offset)
 687 {
 688     ADS_STATUS aret;
 689     krb5_error_code ret;
 690     krb5_context context = NULL;
 691     krb5_principal princ;
 692     krb5_get_init_creds_opt opts;
 693     krb5_creds creds;
 694     char *chpw_princ = NULL, *password;
 695     const char *realm = NULL;
 696
 697     initialize_krb5_error_table();
 698     ret = krb5_init_context(&context);
 699     if (ret) {
 700         DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
 701         return ADS_ERROR_KRB5(ret);
 702     }
 703
 704     if ((ret = smb_krb5_parse_name(context, principal,
 705                                     &princ))) {
 706         krb5_free_context(context);
 707         DEBUG(1,("Failed to parse %s (%s)\n", principal, error_message(ret)));
 708         return ADS_ERROR_KRB5(ret);
 709     }
 710
 711     krb5_get_init_creds_opt_init(&opts);
 712     krb5_get_init_creds_opt_set_tkt_life(&opts, 5*60);
 713     krb5_get_init_creds_opt_set_renew_life(&opts, 0);
 714     krb5_get_init_creds_opt_set_forwardable(&opts, 0);
 715     krb5_get_init_creds_opt_set_proxiable(&opts, 0);
 716
 717     realm = smb_krb5_principal_get_realm(context, princ);
 718
 719     /* We have to obtain an INITIAL changepw ticket for changing password */
 720     if (asprintf(&chpw_princ, "kadmin/changepw@%s", realm) == -1) {
 721         krb5_free_context(context);
 722         DEBUG(1,("ads_krb5_chg_password: asprintf fail\n"));
 723         return ADS_ERROR_NT(NT_STATUS_NO_MEMORY);
 724     }
 725
 726     password = SMB_STRDUP(oldpw);
 727     ret = krb5_get_init_creds_password(context, &creds, princ, password,
 728                                            kerb_prompter, NULL,
 729                                            0, chpw_princ, &opts);
 730     SAFE_FREE(chpw_princ);
 731     SAFE_FREE(password);
 732
 733     if (ret) {
 734       if (ret == KRB5KRB_AP_ERR_BAD_INTEGRITY)
 735         DEBUG(1,("Password incorrect while getting initial ticket"));
 736       else
 737         DEBUG(1,("krb5_get_init_creds_password failed (%s)\n", error_message(ret)));
 738
 739         krb5_free_principal(context, princ);
 740         krb5_free_context(context);
 741         return ADS_ERROR_KRB5(ret);
 742     }
 743
 744     aret = do_krb5_kpasswd_request(context, kdc_host,
 745                                    KRB5_KPASSWD_VERS_CHANGEPW,
 746                                    &creds, principal, newpw);
 747
 748     krb5_free_principal(context, princ);
 749     krb5_free_context(context);
 750
 751     return aret;
 752 }
 753
 754
 755 ADS_STATUS kerberos_set_password(const char *kpasswd_server,
 756                                  const char *auth_principal, const char *auth_password,
 757                                  const char *target_principal, const char *new_password,
 758                                  int time_offset)
 759 {
 760     int ret;
 761
 762     if ((ret = kerberos_kinit_password(auth_principal, auth_password, time_offset, NULL))) {
 763         DEBUG(1,("Failed kinit for principal %s (%s)\n", auth_principal, error_message(ret)));
 764         return ADS_ERROR_KRB5(ret);
 765     }
 766
 767     if (!strcmp(auth_principal, target_principal))
 768         return ads_krb5_chg_password(kpasswd_server, target_principal,
 769                                      auth_password, new_password, time_offset);
 770     else
 771         return ads_krb5_set_password(kpasswd_server, target_principal,
 772                                      new_password, time_offset);
 773 }
 774
 775 #endif