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
  25 #ifdef HAVE_KRB5
  26
  27 #define DEFAULT_KPASSWD_PORT    464
  28
  29 #define KRB5_KPASSWD_VERS_CHANGEPW              1
  30
  31 #define KRB5_KPASSWD_VERS_SETPW                 0xff80
  32 #define KRB5_KPASSWD_VERS_SETPW_ALT             2
  33
  34 #define KRB5_KPASSWD_SUCCESS                    0
  35 #define KRB5_KPASSWD_MALFORMED                  1
  36 #define KRB5_KPASSWD_HARDERROR                  2
  37 #define KRB5_KPASSWD_AUTHERROR                  3
  38 #define KRB5_KPASSWD_SOFTERROR                  4
  39 #define KRB5_KPASSWD_ACCESSDENIED               5
  40 #define KRB5_KPASSWD_BAD_VERSION                6
  41 #define KRB5_KPASSWD_INITIAL_FLAG_NEEDED        7
  42
  43 /* Those are defined by kerberos-set-passwd-02.txt and are probably
  44  * not supported by M$ implementation */
  45 #define KRB5_KPASSWD_POLICY_REJECT              8
  46 #define KRB5_KPASSWD_BAD_PRINCIPAL              9
  47 #define KRB5_KPASSWD_ETYPE_NOSUPP               10
  48
  49 /*
  50  * we've got to be able to distinguish KRB_ERRORs from other
  51  * requests - valid response for CHPW v2 replies.
  52  */
  53
  54 #define krb5_is_krb_error(packet) \
  55         ( packet && packet->length && (((char *)packet->data)[0] == 0x7e || ((char *)packet->data)[0] == 0x5e))
  56
  57 /* This implements kerberos password change protocol as specified in
  58  * kerb-chg-password-02.txt and kerberos-set-passwd-02.txt
  59  * as well as microsoft version of the protocol
  60  * as specified in kerberos-set-passwd-00.txt
  61  */
  62 static DATA_BLOB encode_krb5_setpw(const char *principal, const char *password)
  63 {
  64         char* princ_part1 = NULL;
  65         char* princ_part2 = NULL;
  66         char* realm = NULL;
  67         char* c;
  68         char* princ;
  69
  70         ASN1_DATA *req;
  71         DATA_BLOB ret;
  72
  73
  74         princ = SMB_STRDUP(principal);
  75
  76         if ((c = strchr_m(princ, '/')) == NULL) {
  77                 c = princ;
  78         } else {
  79                 *c = '\0';
  80                 c++;
  81                 princ_part1 = princ;
  82         }
  83
  84         princ_part2 = c;
  85
  86         if ((c = strchr_m(c, '@')) != NULL) {
  87                 *c = '\0';
  88                 c++;
  89                 realm = c;
  90         } else {
  91                 /* We must have a realm component. */
  92                 return data_blob_null;
  93         }
  94
  95         req = asn1_init(talloc_tos());
  96         if (req == NULL) {
  97                 return data_blob_null;
  98         }
  99
 100         asn1_push_tag(req, ASN1_SEQUENCE(0));
 101         asn1_push_tag(req, ASN1_CONTEXT(0));
 102         asn1_write_OctetString(req, password, strlen(password));
 103         asn1_pop_tag(req);
 104
 105         asn1_push_tag(req, ASN1_CONTEXT(1));
 106         asn1_push_tag(req, ASN1_SEQUENCE(0));
 107
 108         asn1_push_tag(req, ASN1_CONTEXT(0));
 109         asn1_write_Integer(req, 1);
 110         asn1_pop_tag(req);
 111
 112         asn1_push_tag(req, ASN1_CONTEXT(1));
 113         asn1_push_tag(req, ASN1_SEQUENCE(0));
 114
 115         if (princ_part1) {
 116                 asn1_write_GeneralString(req, princ_part1);
 117         }
 118
 119         asn1_write_GeneralString(req, princ_part2);
 120         asn1_pop_tag(req);
 121         asn1_pop_tag(req);
 122         asn1_pop_tag(req);
 123         asn1_pop_tag(req);
 124
 125         asn1_push_tag(req, ASN1_CONTEXT(2));
 126         asn1_write_GeneralString(req, realm);
 127         asn1_pop_tag(req);
 128         asn1_pop_tag(req);
 129
 130         ret = data_blob(req->data, req->length);
 131         asn1_free(req);
 132
 133         free(princ);
 134
 135         return ret;
 136 }
 137
 138 static krb5_error_code build_kpasswd_request(uint16 pversion,
 139                                            krb5_context context,
 140                                            krb5_auth_context auth_context,
 141                                            krb5_data *ap_req,
 142                                            const char *princ,
 143                                            const char *passwd,
 144                                            bool use_tcp,
 145                                            krb5_data *packet)
 146 {
 147         krb5_error_code ret;
 148         krb5_data cipherpw;
 149         krb5_data encoded_setpw;
 150         krb5_replay_data replay;
 151         char *p, *msg_start;
 152         DATA_BLOB setpw;
 153         unsigned int msg_length;
 154
 155         ret = krb5_auth_con_setflags(context,
 156                                      auth_context,KRB5_AUTH_CONTEXT_DO_SEQUENCE);
 157         if (ret) {
 158                 DEBUG(1,("krb5_auth_con_setflags failed (%s)\n",
 159                          error_message(ret)));
 160                 return ret;
 161         }
 162
 163         /* handle protocol differences in chpw and setpw */
 164         if (pversion  == KRB5_KPASSWD_VERS_CHANGEPW)
 165                 setpw = data_blob(passwd, strlen(passwd));
 166         else if (pversion == KRB5_KPASSWD_VERS_SETPW ||
 167                  pversion == KRB5_KPASSWD_VERS_SETPW_ALT)
 168                 setpw = encode_krb5_setpw(princ, passwd);
 169         else
 170                 return EINVAL;
 171
 172         if (setpw.data == NULL || setpw.length == 0) {
 173                 return EINVAL;
 174         }
 175
 176         encoded_setpw.data = (char *)setpw.data;
 177         encoded_setpw.length = setpw.length;
 178
 179         ret = krb5_mk_priv(context, auth_context,
 180                            &encoded_setpw, &cipherpw, &replay);
 181
 182         data_blob_free(&setpw);         /*from 'encode_krb5_setpw(...)' */
 183
 184         if (ret) {
 185                 DEBUG(1,("krb5_mk_priv failed (%s)\n", error_message(ret)));
 186                 return ret;
 187         }
 188
 189         packet->data = (char *)SMB_MALLOC(ap_req->length + cipherpw.length + (use_tcp ? 10 : 6 ));
 190         if (!packet->data)
 191                 return -1;
 192
 193
 194
 195         /* see the RFC for details */
 196
 197         msg_start = p = ((char *)packet->data) + (use_tcp ? 4 : 0);
 198         p += 2;
 199         RSSVAL(p, 0, pversion);
 200         p += 2;
 201         RSSVAL(p, 0, ap_req->length);
 202         p += 2;
 203         memcpy(p, ap_req->data, ap_req->length);
 204         p += ap_req->length;
 205         memcpy(p, cipherpw.data, cipherpw.length);
 206         p += cipherpw.length;
 207         packet->length = PTR_DIFF(p,packet->data);
 208         msg_length = PTR_DIFF(p,msg_start);
 209
 210         if (use_tcp) {
 211                 RSIVAL(packet->data, 0, msg_length);
 212         }
 213         RSSVAL(msg_start, 0, msg_length);
 214
 215         free(cipherpw.data);    /* from 'krb5_mk_priv(...)' */
 216
 217         return 0;
 218 }
 219
 220 static const struct kpasswd_errors {
 221         int result_code;
 222         const char *error_string;
 223 } kpasswd_errors[] = {
 224         {KRB5_KPASSWD_MALFORMED, "Malformed request error"},
 225         {KRB5_KPASSWD_HARDERROR, "Server error"},
 226         {KRB5_KPASSWD_AUTHERROR, "Authentication error"},
 227         {KRB5_KPASSWD_SOFTERROR, "Password change rejected"},
 228         {KRB5_KPASSWD_ACCESSDENIED, "Client does not have proper authorization"},
 229         {KRB5_KPASSWD_BAD_VERSION, "Protocol version not supported"},
 230         {KRB5_KPASSWD_INITIAL_FLAG_NEEDED, "Authorization ticket must have initial flag set"},
 231         {KRB5_KPASSWD_POLICY_REJECT, "Password rejected due to policy requirements"},
 232         {KRB5_KPASSWD_BAD_PRINCIPAL, "Target principal does not exist"},
 233         {KRB5_KPASSWD_ETYPE_NOSUPP, "Unsupported encryption type"},
 234         {0, NULL}
 235 };
 236
 237 static krb5_error_code setpw_result_code_string(krb5_context context,
 238                                                 int result_code,
 239                                                 const char **code_string)
 240 {
 241         unsigned int idx = 0;
 242
 243         while (kpasswd_errors[idx].error_string != NULL) {
 244                 if (kpasswd_errors[idx].result_code ==
 245                     result_code) {
 246                         *code_string = kpasswd_errors[idx].error_string;
 247                         return 0;
 248                 }
 249                 idx++;
 250         }
 251         *code_string = "Password change failed";
 252         return (0);
 253 }
 254
 255  krb5_error_code kpasswd_err_to_krb5_err(krb5_error_code res_code)
 256 {
 257         switch(res_code) {
 258                 case KRB5_KPASSWD_ACCESSDENIED:
 259                         return KRB5KDC_ERR_BADOPTION;
 260                 case KRB5_KPASSWD_INITIAL_FLAG_NEEDED:
 261                         return KRB5KDC_ERR_BADOPTION;
 262                         /* return KV5M_ALT_METHOD; MIT-only define */
 263                 case KRB5_KPASSWD_ETYPE_NOSUPP:
 264                         return KRB5KDC_ERR_ETYPE_NOSUPP;
 265                 case KRB5_KPASSWD_BAD_PRINCIPAL:
 266                         return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
 267                 case KRB5_KPASSWD_POLICY_REJECT:
 268                 case KRB5_KPASSWD_SOFTERROR:
 269                         return KRB5KDC_ERR_POLICY;
 270                 default:
 271                         return KRB5KRB_ERR_GENERIC;
 272         }
 273 }
 274 static krb5_error_code parse_setpw_reply(krb5_context context,
 275                                          bool use_tcp,
 276                                          krb5_auth_context auth_context,
 277                                          krb5_data *packet)
 278 {
 279         krb5_data ap_rep;
 280         char *p;
 281         int vnum, ret, res_code;
 282         krb5_data cipherresult;
 283         krb5_data clearresult;
 284         krb5_ap_rep_enc_part *ap_rep_enc;
 285         krb5_replay_data replay;
 286         unsigned int msg_length = packet->length;
 287
 288
 289         if (packet->length < (use_tcp ? 8 : 4)) {
 290                 return KRB5KRB_AP_ERR_MODIFIED;
 291         }
 292
 293         p = (char *)packet->data;
 294         /*
 295         ** see if it is an error
 296         */
 297         if (krb5_is_krb_error(packet)) {
 298
 299                 ret = handle_krberror_packet(context, packet);
 300                 if (ret) {
 301                         return ret;
 302                 }
 303         }
 304
 305
 306         /* tcp... */
 307         if (use_tcp) {
 308                 msg_length -= 4;
 309                 if (RIVAL(p, 0) != msg_length) {
 310                         DEBUG(1,("Bad TCP packet length (%d/%d) from kpasswd server\n",
 311                         RIVAL(p, 0), msg_length));
 312                         return KRB5KRB_AP_ERR_MODIFIED;
 313                 }
 314
 315                 p += 4;
 316         }
 317
 318         if (RSVAL(p, 0) != msg_length) {
 319                 DEBUG(1,("Bad packet length (%d/%d) from kpasswd server\n",
 320                          RSVAL(p, 0), msg_length));
 321                 return KRB5KRB_AP_ERR_MODIFIED;
 322         }
 323
 324         p += 2;
 325
 326         vnum = RSVAL(p, 0); p += 2;
 327
 328         /* FIXME: According to standard there is only one type of reply */
 329         if (vnum != KRB5_KPASSWD_VERS_SETPW &&
 330             vnum != KRB5_KPASSWD_VERS_SETPW_ALT &&
 331             vnum != KRB5_KPASSWD_VERS_CHANGEPW) {
 332                 DEBUG(1,("Bad vnum (%d) from kpasswd server\n", vnum));
 333                 return KRB5KDC_ERR_BAD_PVNO;
 334         }
 335
 336         ap_rep.length = RSVAL(p, 0); p += 2;
 337
 338         if (p + ap_rep.length >= (char *)packet->data + packet->length) {
 339                 DEBUG(1,("ptr beyond end of packet from kpasswd server\n"));
 340                 return KRB5KRB_AP_ERR_MODIFIED;
 341         }
 342
 343         if (ap_rep.length == 0) {
 344                 DEBUG(1,("got unencrypted setpw result?!\n"));
 345                 return KRB5KRB_AP_ERR_MODIFIED;
 346         }
 347
 348         /* verify ap_rep */
 349         ap_rep.data = p;
 350         p += ap_rep.length;
 351
 352         ret = krb5_rd_rep(context, auth_context, &ap_rep, &ap_rep_enc);
 353         if (ret) {
 354                 DEBUG(1,("failed to rd setpw reply (%s)\n", error_message(ret)));
 355                 return KRB5KRB_AP_ERR_MODIFIED;
 356         }
 357
 358         krb5_free_ap_rep_enc_part(context, ap_rep_enc);
 359
 360         cipherresult.data = p;
 361         cipherresult.length = ((char *)packet->data + packet->length) - p;
 362
 363         ret = krb5_rd_priv(context, auth_context, &cipherresult, &clearresult,
 364                            &replay);
 365         if (ret) {
 366                 DEBUG(1,("failed to decrypt setpw reply (%s)\n", error_message(ret)));
 367                 return KRB5KRB_AP_ERR_MODIFIED;
 368         }
 369
 370         if (clearresult.length < 2) {
 371                 free(clearresult.data);
 372                 ret = KRB5KRB_AP_ERR_MODIFIED;
 373                 return KRB5KRB_AP_ERR_MODIFIED;
 374         }
 375
 376         p = (char *)clearresult.data;
 377
 378         res_code = RSVAL(p, 0);
 379
 380         free(clearresult.data);
 381
 382         if ((res_code < KRB5_KPASSWD_SUCCESS) ||
 383             (res_code > KRB5_KPASSWD_ETYPE_NOSUPP)) {
 384                 return KRB5KRB_AP_ERR_MODIFIED;
 385         }
 386
 387         if (res_code == KRB5_KPASSWD_SUCCESS) {
 388                 return 0;
 389         } else {
 390                 const char *errstr;
 391                 setpw_result_code_string(context, res_code, &errstr);
 392                 DEBUG(1, ("Error changing password: %s (%d)\n", errstr, res_code));
 393
 394                 return kpasswd_err_to_krb5_err(res_code);
 395         }
 396 }
 397
 398 static ADS_STATUS do_krb5_kpasswd_request(krb5_context context,
 399                                           const char *kdc_host,
 400                                           uint16 pversion,
 401                                           krb5_creds *credsp,
 402                                           const char *princ,
 403                                           const char *newpw)
 404 {
 405         krb5_auth_context auth_context = NULL;
 406         krb5_data ap_req, chpw_req, chpw_rep;
 407         int ret, sock;
 408         socklen_t addr_len;
 409         struct sockaddr_storage remote_addr, local_addr;
 410         struct sockaddr_storage addr;
 411         krb5_address local_kaddr, remote_kaddr;
 412         bool use_tcp = False;
 413
 414
 415         if (!interpret_string_addr(&addr, kdc_host, 0)) {
 416         }
 417
 418         ret = krb5_mk_req_extended(context, &auth_context, AP_OPTS_USE_SUBKEY,
 419                                    NULL, credsp, &ap_req);
 420         if (ret) {
 421                 DEBUG(1,("krb5_mk_req_extended failed (%s)\n", error_message(ret)));
 422                 return ADS_ERROR_KRB5(ret);
 423         }
 424
 425         do {
 426
 427                 if (!use_tcp) {
 428
 429                         sock = open_udp_socket(kdc_host, DEFAULT_KPASSWD_PORT);
 430                         if (sock == -1) {
 431                                 int rc = errno;
 432                                 SAFE_FREE(ap_req.data);
 433                                 krb5_auth_con_free(context, auth_context);
 434                                 DEBUG(1,("failed to open kpasswd socket to %s "
 435                                          "(%s)\n", kdc_host, strerror(errno)));
 436                                 return ADS_ERROR_SYSTEM(rc);
 437                         }
 438                 } else {
 439                         NTSTATUS status;
 440                         status = open_socket_out(&addr, DEFAULT_KPASSWD_PORT,
 441                                                  LONG_CONNECT_TIMEOUT, &sock);
 442                         if (!NT_STATUS_IS_OK(status)) {
 443                                 SAFE_FREE(ap_req.data);
 444                                 krb5_auth_con_free(context, auth_context);
 445                                 DEBUG(1,("failed to open kpasswd socket to %s "
 446                                          "(%s)\n", kdc_host,
 447                                          nt_errstr(status)));
 448                                 return ADS_ERROR_NT(status);
 449                         }
 450                 }
 451
 452                 addr_len = sizeof(remote_addr);
 453                 if (getpeername(sock, (struct sockaddr *)&remote_addr, &addr_len) != 0) {
 454                         close(sock);
 455                         SAFE_FREE(ap_req.data);
 456                         krb5_auth_con_free(context, auth_context);
 457                         DEBUG(1,("getpeername() failed (%s)\n", error_message(errno)));
 458                         return ADS_ERROR_SYSTEM(errno);
 459                 }
 460                 addr_len = sizeof(local_addr);
 461                 if (getsockname(sock, (struct sockaddr *)&local_addr, &addr_len) != 0) {
 462                         close(sock);
 463                         SAFE_FREE(ap_req.data);
 464                         krb5_auth_con_free(context, auth_context);
 465                         DEBUG(1,("getsockname() failed (%s)\n", error_message(errno)));
 466                         return ADS_ERROR_SYSTEM(errno);
 467                 }
 468                 if (!setup_kaddr(&remote_kaddr, &remote_addr) ||
 469                                 !setup_kaddr(&local_kaddr, &local_addr)) {
 470                         DEBUG(1,("do_krb5_kpasswd_request: "
 471                                 "Failed to setup addresses.\n"));
 472                         close(sock);
 473                         SAFE_FREE(ap_req.data);
 474                         krb5_auth_con_free(context, auth_context);
 475                         errno = EINVAL;
 476                         return ADS_ERROR_SYSTEM(EINVAL);
 477                 }
 478
 479                 ret = krb5_auth_con_setaddrs(context, auth_context, &local_kaddr, NULL);
 480                 if (ret) {
 481                         close(sock);
 482                         SAFE_FREE(ap_req.data);
 483                         krb5_auth_con_free(context, auth_context);
 484                         DEBUG(1,("krb5_auth_con_setaddrs failed (%s)\n", error_message(ret)));
 485                         return ADS_ERROR_KRB5(ret);
 486                 }
 487
 488                 ret = build_kpasswd_request(pversion, context, auth_context, &ap_req,
 489                                           princ, newpw, use_tcp, &chpw_req);
 490                 if (ret) {
 491                         close(sock);
 492                         SAFE_FREE(ap_req.data);
 493                         krb5_auth_con_free(context, auth_context);
 494                         DEBUG(1,("build_setpw_request failed (%s)\n", error_message(ret)));
 495                         return ADS_ERROR_KRB5(ret);
 496                 }
 497
 498                 ret = write(sock, chpw_req.data, chpw_req.length);
 499
 500                 if (ret != chpw_req.length) {
 501                         close(sock);
 502                         SAFE_FREE(chpw_req.data);
 503                         SAFE_FREE(ap_req.data);
 504                         krb5_auth_con_free(context, auth_context);
 505                         DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
 506                         return ADS_ERROR_SYSTEM(errno);
 507                 }
 508
 509                 SAFE_FREE(chpw_req.data);
 510
 511                 chpw_rep.length = 1500;
 512                 chpw_rep.data = (char *) SMB_MALLOC(chpw_rep.length);
 513                 if (!chpw_rep.data) {
 514                         close(sock);
 515                         SAFE_FREE(ap_req.data);
 516                         krb5_auth_con_free(context, auth_context);
 517                         DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
 518                         errno = ENOMEM;
 519                         return ADS_ERROR_SYSTEM(errno);
 520                 }
 521
 522                 ret = read(sock, chpw_rep.data, chpw_rep.length);
 523                 if (ret < 0) {
 524                         close(sock);
 525                         SAFE_FREE(chpw_rep.data);
 526                         SAFE_FREE(ap_req.data);
 527                         krb5_auth_con_free(context, auth_context);
 528                         DEBUG(1,("recv of chpw reply failed (%s)\n", strerror(errno)));
 529                         return ADS_ERROR_SYSTEM(errno);
 530                 }
 531
 532                 close(sock);
 533                 chpw_rep.length = ret;
 534
 535                 ret = krb5_auth_con_setaddrs(context, auth_context, NULL,&remote_kaddr);
 536                 if (ret) {
 537                         SAFE_FREE(chpw_rep.data);
 538                         SAFE_FREE(ap_req.data);
 539                         krb5_auth_con_free(context, auth_context);
 540                         DEBUG(1,("krb5_auth_con_setaddrs on reply failed (%s)\n",
 541                                  error_message(ret)));
 542                         return ADS_ERROR_KRB5(ret);
 543                 }
 544
 545                 ret = parse_setpw_reply(context, use_tcp, auth_context, &chpw_rep);
 546                 SAFE_FREE(chpw_rep.data);
 547
 548                 if (ret) {
 549
 550                         if (ret == KRB5KRB_ERR_RESPONSE_TOO_BIG && !use_tcp) {
 551                                 DEBUG(5, ("Trying setpw with TCP!!!\n"));
 552                                 use_tcp = True;
 553                                 continue;
 554                         }
 555
 556                         SAFE_FREE(ap_req.data);
 557                         krb5_auth_con_free(context, auth_context);
 558                         DEBUG(1,("parse_setpw_reply failed (%s)\n",
 559                                  error_message(ret)));
 560                         return ADS_ERROR_KRB5(ret);
 561                 }
 562
 563                 SAFE_FREE(ap_req.data);
 564                 krb5_auth_con_free(context, auth_context);
 565         } while ( ret );
 566
 567         return ADS_SUCCESS;
 568 }
 569
 570 ADS_STATUS ads_krb5_set_password(const char *kdc_host, const char *princ,
 571                                  const char *newpw, int time_offset)
 572 {
 573
 574         ADS_STATUS aret;
 575         krb5_error_code ret = 0;
 576         krb5_context context = NULL;
 577         krb5_principal principal = NULL;
 578         char *princ_name = NULL;
 579         char *realm = NULL;
 580         krb5_creds creds, *credsp = NULL;
 581 #if KRB5_PRINC_REALM_RETURNS_REALM
 582         krb5_realm orig_realm;
 583 #else
 584         krb5_data orig_realm;
 585 #endif
 586         krb5_ccache ccache = NULL;
 587
 588         ZERO_STRUCT(creds);
 589
 590         initialize_krb5_error_table();
 591         ret = krb5_init_context(&context);
 592         if (ret) {
 593                 DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
 594                 return ADS_ERROR_KRB5(ret);
 595         }
 596
 597         if (time_offset != 0) {
 598                 krb5_set_real_time(context, time(NULL) + time_offset, 0);
 599         }
 600
 601         ret = krb5_cc_default(context, &ccache);
 602         if (ret) {
 603                 krb5_free_context(context);
 604                 DEBUG(1,("Failed to get default creds (%s)\n", error_message(ret)));
 605                 return ADS_ERROR_KRB5(ret);
 606         }
 607
 608         realm = strchr_m(princ, '@');
 609         if (!realm) {
 610                 krb5_cc_close(context, ccache);
 611                 krb5_free_context(context);
 612                 DEBUG(1,("Failed to get realm\n"));
 613                 return ADS_ERROR_KRB5(-1);
 614         }
 615         realm++;
 616
 617         if (asprintf(&princ_name, "kadmin/changepw@%s", realm) == -1) {
 618                 krb5_cc_close(context, ccache);
 619                 krb5_free_context(context);
 620                 DEBUG(1,("asprintf failed\n"));
 621                 return ADS_ERROR_NT(NT_STATUS_NO_MEMORY);
 622         }
 623
 624         ret = smb_krb5_parse_name(context, princ_name, &creds.server);
 625         if (ret) {
 626                 krb5_cc_close(context, ccache);
 627                 krb5_free_context(context);
 628                 DEBUG(1,("Failed to parse kadmin/changepw (%s)\n", error_message(ret)));
 629                 return ADS_ERROR_KRB5(ret);
 630         }
 631
 632         /* parse the principal we got as a function argument */
 633         ret = smb_krb5_parse_name(context, princ, &principal);
 634         if (ret) {
 635                 krb5_cc_close(context, ccache);
 636                 krb5_free_principal(context, creds.server);
 637                 krb5_free_context(context);
 638                 DEBUG(1,("Failed to parse %s (%s)\n", princ_name, error_message(ret)));
 639                 free(princ_name);
 640                 return ADS_ERROR_KRB5(ret);
 641         }
 642
 643         free(princ_name);
 644
 645         /* The creds.server principal takes ownership of this memory.
 646                 Remember to set back to original value before freeing. */
 647         orig_realm = *krb5_princ_realm(context, creds.server);
 648         krb5_princ_set_realm(context, creds.server, krb5_princ_realm(context, principal));
 649
 650         ret = krb5_cc_get_principal(context, ccache, &creds.client);
 651         if (ret) {
 652                 krb5_cc_close(context, ccache);
 653                 krb5_princ_set_realm(context, creds.server, &orig_realm);
 654                 krb5_free_principal(context, creds.server);
 655                 krb5_free_principal(context, principal);
 656                 krb5_free_context(context);
 657                 DEBUG(1,("Failed to get principal from ccache (%s)\n",
 658                          error_message(ret)));
 659                 return ADS_ERROR_KRB5(ret);
 660         }
 661
 662         ret = krb5_get_credentials(context, 0, ccache, &creds, &credsp);
 663         if (ret) {
 664                 krb5_cc_close(context, ccache);
 665                 krb5_free_principal(context, creds.client);
 666                 krb5_princ_set_realm(context, creds.server, &orig_realm);
 667                 krb5_free_principal(context, creds.server);
 668                 krb5_free_principal(context, principal);
 669                 krb5_free_context(context);
 670                 DEBUG(1,("krb5_get_credentials failed (%s)\n", error_message(ret)));
 671                 return ADS_ERROR_KRB5(ret);
 672         }
 673
 674         /* we might have to call krb5_free_creds(...) from now on ... */
 675
 676         aret = do_krb5_kpasswd_request(context, kdc_host,
 677                                        KRB5_KPASSWD_VERS_SETPW,
 678                                        credsp, princ, newpw);
 679
 680         krb5_free_creds(context, credsp);
 681         krb5_free_principal(context, creds.client);
 682         krb5_princ_set_realm(context, creds.server, &orig_realm);
 683         krb5_free_principal(context, creds.server);
 684         krb5_free_principal(context, principal);
 685         krb5_cc_close(context, ccache);
 686         krb5_free_context(context);
 687
 688         return aret;
 689 }
 690
 691 /*
 692   we use a prompter to avoid a crash bug in the kerberos libs when
 693   dealing with empty passwords
 694   this prompter is just a string copy ...
 695 */
 696 static krb5_error_code
 697 kerb_prompter(krb5_context ctx, void *data,
 698                const char *name,
 699                const char *banner,
 700                int num_prompts,
 701                krb5_prompt prompts[])
 702 {
 703         if (num_prompts == 0) return 0;
 704
 705         memset(prompts[0].reply->data, 0, prompts[0].reply->length);
 706         if (prompts[0].reply->length > 0) {
 707                 if (data) {
 708                         strncpy((char *)prompts[0].reply->data,
 709                                 (const char *)data,
 710                                 prompts[0].reply->length-1);
 711                         prompts[0].reply->length = strlen((const char *)prompts[0].reply->data);
 712                 } else {
 713                         prompts[0].reply->length = 0;
 714                 }
 715         }
 716         return 0;
 717 }
 718
 719 static ADS_STATUS ads_krb5_chg_password(const char *kdc_host,
 720                                         const char *principal,
 721                                         const char *oldpw,
 722                                         const char *newpw,
 723                                         int time_offset)
 724 {
 725     ADS_STATUS aret;
 726     krb5_error_code ret;
 727     krb5_context context = NULL;
 728     krb5_principal princ;
 729     krb5_get_init_creds_opt opts;
 730     krb5_creds creds;
 731     char *chpw_princ = NULL, *password;
 732
 733     initialize_krb5_error_table();
 734     ret = krb5_init_context(&context);
 735     if (ret) {
 736         DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
 737         return ADS_ERROR_KRB5(ret);
 738     }
 739
 740     if ((ret = smb_krb5_parse_name(context, principal,
 741                                     &princ))) {
 742         krb5_free_context(context);
 743         DEBUG(1,("Failed to parse %s (%s)\n", principal, error_message(ret)));
 744         return ADS_ERROR_KRB5(ret);
 745     }
 746
 747     krb5_get_init_creds_opt_init(&opts);
 748     krb5_get_init_creds_opt_set_tkt_life(&opts, 5*60);
 749     krb5_get_init_creds_opt_set_renew_life(&opts, 0);
 750     krb5_get_init_creds_opt_set_forwardable(&opts, 0);
 751     krb5_get_init_creds_opt_set_proxiable(&opts, 0);
 752
 753     /* We have to obtain an INITIAL changepw ticket for changing password */
 754     if (asprintf(&chpw_princ, "kadmin/changepw@%s",
 755                                 (char *) krb5_princ_realm(context, princ)) == -1) {
 756         krb5_free_context(context);
 757         DEBUG(1,("ads_krb5_chg_password: asprintf fail\n"));
 758         return ADS_ERROR_NT(NT_STATUS_NO_MEMORY);
 759     }
 760
 761     password = SMB_STRDUP(oldpw);
 762     ret = krb5_get_init_creds_password(context, &creds, princ, password,
 763                                            kerb_prompter, NULL,
 764                                            0, chpw_princ, &opts);
 765     SAFE_FREE(chpw_princ);
 766     SAFE_FREE(password);
 767
 768     if (ret) {
 769       if (ret == KRB5KRB_AP_ERR_BAD_INTEGRITY)
 770         DEBUG(1,("Password incorrect while getting initial ticket"));
 771       else
 772         DEBUG(1,("krb5_get_init_creds_password failed (%s)\n", error_message(ret)));
 773
 774         krb5_free_principal(context, princ);
 775         krb5_free_context(context);
 776         return ADS_ERROR_KRB5(ret);
 777     }
 778
 779     aret = do_krb5_kpasswd_request(context, kdc_host,
 780                                    KRB5_KPASSWD_VERS_CHANGEPW,
 781                                    &creds, principal, newpw);
 782
 783     krb5_free_principal(context, princ);
 784     krb5_free_context(context);
 785
 786     return aret;
 787 }
 788
 789
 790 ADS_STATUS kerberos_set_password(const char *kpasswd_server,
 791                                  const char *auth_principal, const char *auth_password,
 792                                  const char *target_principal, const char *new_password,
 793                                  int time_offset)
 794 {
 795     int ret;
 796
 797     if ((ret = kerberos_kinit_password(auth_principal, auth_password, time_offset, NULL))) {
 798         DEBUG(1,("Failed kinit for principal %s (%s)\n", auth_principal, error_message(ret)));
 799         return ADS_ERROR_KRB5(ret);
 800     }
 801
 802     if (!strcmp(auth_principal, target_principal))
 803         return ads_krb5_chg_password(kpasswd_server, target_principal,
 804                                      auth_password, new_password, time_offset);
 805     else
 806         return ads_krb5_set_password(kpasswd_server, target_principal,
 807                                      new_password, time_offset);
 808 }
 809
 810 #endif