lib/krb5/changepw.c

   1 /*
   2  * Copyright (c) 1997 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by Kungliga Tekniska
  20  *      Högskolan and its contributors.
  21  *
  22  * 4. Neither the name of the Institute nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 #include <krb5_locl.h>
  40
  41 RCSID("$Id$");
  42
  43 static krb5_error_code
  44 get_kdc_address (krb5_context context,
  45                  krb5_realm realm,
  46                  struct sockaddr *sa,
  47                  int *sa_size)
  48 {
  49     krb5_error_code ret;
  50     struct hostent *hostent;
  51     char **hostlist;
  52     char *dot;
  53     char *p;
  54
  55     ret = krb5_get_krbhst (context,
  56                            &realm,
  57                            &hostlist);
  58     if (ret)
  59         return ret;
  60
  61     p = *hostlist;
  62
  63     dot = strchr (p, ':');
  64     if (dot)
  65         *dot = '\0';
  66
  67 #ifdef HAVE_GETHOSTBYNAME2
  68     hostent = gethostbyname2 (p, AF_INET6);
  69     if (hostent == NULL)
  70         hostent = gethostbyname2 (p, AF_INET);
  71 #else
  72     hostent = gethostbyname (p);
  73 #endif
  74     krb5_free_krbhst (context, hostlist);
  75     if (hostent == NULL)
  76         return h_errno;         /* XXX */
  77
  78     return krb5_h_addr2sockaddr (hostent->h_addrtype,
  79                                  hostent->h_addr_list[0],
  80                                  sa,
  81                                  sa_size,
  82                                  krb5_getportbyname (context,
  83                                                      "kpasswd",
  84                                                      "udp",
  85                                                      KPASSWD_PORT));
  86 }
  87
  88 static krb5_error_code
  89 send_request (krb5_context context,
  90               krb5_auth_context *auth_context,
  91               krb5_creds *creds,
  92               int sock,
  93               struct sockaddr *sa,
  94               int sa_size,
  95               char *passwd)
  96 {
  97     krb5_error_code ret;
  98     krb5_data ap_req_data;
  99     krb5_data krb_priv_data;
 100     krb5_data passwd_data;
 101     size_t len;
 102     u_char header[6];
 103     u_char *p;
 104     struct iovec iov[3];
 105     struct msghdr msghdr;
 106
 107     krb5_data_zero (&ap_req_data);
 108
 109     ret = krb5_mk_req_extended (context,
 110                                 auth_context,
 111                                 AP_OPTS_MUTUAL_REQUIRED,
 112                                 NULL, /* in_data */
 113                                 creds,
 114                                 &ap_req_data);
 115     if (ret)
 116         return ret;
 117
 118     passwd_data.data   = passwd;
 119     passwd_data.length = strlen(passwd);
 120
 121     krb5_data_zero (&krb_priv_data);
 122
 123     ret = krb5_mk_priv (context,
 124                         *auth_context,
 125                         &passwd_data,
 126                         &krb_priv_data,
 127                         NULL);
 128     if (ret)
 129         return ret;
 130
 131     len = 6 + ap_req_data.length + krb_priv_data.length;
 132     p = header;
 133     *p++ = (len >> 8) & 0xFF;
 134     *p++ = (len >> 0) & 0xFF;
 135     *p++ = 0;
 136     *p++ = 1;
 137     *p++ = (ap_req_data.length >> 8) & 0xFF;
 138     *p++ = (ap_req_data.length >> 0) & 0xFF;
 139
 140     memset(&msghdr, 0, sizeof(msghdr));
 141     msghdr.msg_name       = (void *)sa;
 142     msghdr.msg_namelen    = sa_size;
 143     msghdr.msg_iov        = iov;
 144     msghdr.msg_iovlen     = sizeof(iov)/sizeof(*iov);
 145 #if 0
 146     msghdr.msg_control    = NULL;
 147     msghdr.msg_controllen = 0;
 148 #endif
 149
 150     iov[0].iov_base    = (void*)header;
 151     iov[0].iov_len     = 6;
 152     iov[1].iov_base    = ap_req_data.data;
 153     iov[1].iov_len     = ap_req_data.length;
 154     iov[2].iov_base    = krb_priv_data.data;
 155     iov[2].iov_len     = krb_priv_data.length;
 156
 157     if (sendmsg (sock, &msghdr, 0) < 0)
 158         return errno;
 159
 160     krb5_data_free (&ap_req_data);
 161     krb5_data_free (&krb_priv_data);
 162     return 0;
 163 }
 164
 165 static void
 166 str2data (krb5_data *d,
 167           char *fmt,
 168           ...)
 169 {
 170     char *p;
 171     size_t len;
 172     va_list args;
 173
 174     va_start(args, fmt);
 175     d->length = vasprintf ((char **)&d->data, fmt, args);
 176     va_end(args);
 177 }
 178
 179 static krb5_error_code
 180 process_reply (krb5_context context,
 181                krb5_auth_context auth_context,
 182                int sock,
 183                int *result_code,
 184                krb5_data *result_code_string,
 185                krb5_data *result_string)
 186 {
 187     krb5_error_code ret;
 188     u_char reply[BUFSIZ];
 189     size_t len;
 190     u_int16_t pkt_len, pkt_ver;
 191     krb5_data ap_rep_data;
 192
 193     ret = recvfrom (sock, reply, sizeof(reply), 0, NULL, NULL);
 194     if (ret < 0)
 195         return errno;
 196
 197     len = ret;
 198     pkt_len = (reply[0] << 8) | (reply[1]);
 199     pkt_ver = (reply[2] << 8) | (reply[3]);
 200
 201     if (pkt_len != len) {
 202         str2data (result_string, "client: wrong len in reply");
 203         *result_code = KRB5_KPASSWD_MALFORMED;
 204         return 0;
 205     }
 206     if (pkt_ver != 0x0001) {
 207         str2data (result_string,
 208                   "client: wrong version number (%d)", pkt_ver);
 209         *result_code = KRB5_KPASSWD_MALFORMED;
 210         return 0;
 211     }
 212
 213     ap_rep_data.data = reply + 6;
 214     ap_rep_data.length  = (reply[4] << 8) | (reply[5]);
 215
 216     if (ap_rep_data.length) {
 217         krb5_ap_rep_enc_part *ap_rep;
 218         krb5_data priv_data;
 219         u_char *p;
 220
 221         ret = krb5_rd_rep (context,
 222                            auth_context,
 223                            &ap_rep_data,
 224                            &ap_rep);
 225         if (ret)
 226             return ret;
 227
 228         krb5_free_ap_rep_enc_part (context, ap_rep);
 229
 230         priv_data.data   = (u_char*)ap_rep_data.data + ap_rep_data.length;
 231         priv_data.length = len - ap_rep_data.length - 6;
 232
 233         ret = krb5_rd_priv (context,
 234                             auth_context,
 235                             &priv_data,
 236                             result_code_string,
 237                             NULL);
 238         if (ret) {
 239             krb5_data_free (result_code_string);
 240             return ret;
 241         }
 242
 243         if (result_code_string->length < 2) {
 244             *result_code = KRB5_KPASSWD_MALFORMED;
 245             str2data (result_string,
 246                       "client: bad length in result");
 247             return 0;
 248         }
 249         p = result_code_string->data;
 250
 251         *result_code = (p[0] << 8) | p[1];
 252         krb5_data_copy (result_string,
 253                         (unsigned char*)result_code_string->data + 2,
 254                         result_code_string->length - 2);
 255         return 0;
 256     } else {
 257         KRB_ERROR error;
 258         size_t size;
 259         u_char *p;
 260
 261         ret = decode_KRB_ERROR(reply + 6, len - 6, &error, &size);
 262         if (ret) {
 263             return ret;
 264         }
 265         if (error.e_data->length < 2) {
 266             krb5_warnx (context, "too short e_data to print anything usable");
 267             return 1;
 268         }
 269
 270         p = error.e_data->data;
 271         *result_code = (p[0] << 8) | p[1];
 272         krb5_data_copy (result_string,
 273                         p + 2,
 274                         error.e_data->length - 2);
 275         return 0;
 276     }
 277 }
 278
 279 krb5_error_code
 280 krb5_change_password (krb5_context      context,
 281                       krb5_creds        *creds,
 282                       char              *newpw,
 283                       int               *result_code,
 284                       krb5_data         *result_code_string,
 285                       krb5_data         *result_string)
 286 {
 287     krb5_error_code ret;
 288     krb5_auth_context auth_context = NULL;
 289     krb5_creds cred;
 290     int sock;
 291     int i;
 292     char *buf;
 293     struct sockaddr *sa;
 294     int sa_size;
 295
 296     ret = krb5_auth_con_init (context, &auth_context);
 297     if (ret)
 298         return ret;
 299
 300     buf = malloc (krb5_max_sockaddr_size ());
 301     if (buf == NULL) {
 302         ret = ENOMEM;
 303         goto out;
 304     }
 305     sa = (struct sockaddr *)buf;
 306
 307     ret = get_kdc_address (context, creds->client->realm, sa, &sa_size);
 308     if (ret)
 309         goto out;
 310
 311     sock = socket (sa->sa_family, SOCK_DGRAM, 0);
 312     if (sock < 0) {
 313         ret = errno;
 314         goto out;
 315     }
 316
 317     krb5_auth_con_setflags (context, auth_context,
 318                             KRB5_AUTH_CONTEXT_DO_SEQUENCE);
 319
 320     for (i = 0; i < 5; ++i) {
 321         struct fd_set fdset;
 322         struct timeval tv;
 323
 324         ret = send_request (context,
 325                             &auth_context,
 326                             creds,
 327                             sock,
 328                             sa,
 329                             sa_size,
 330                             newpw);
 331         if (ret)
 332             goto out;
 333
 334         FD_ZERO(&fdset);
 335         FD_SET(sock, &fdset);
 336         tv.tv_usec = 0;
 337         tv.tv_sec  = 1 << i;
 338
 339         ret = select (sock + 1, &fdset, NULL, NULL, &tv);
 340         if (ret < 0 && errno != EINTR)
 341             goto out;
 342         if (ret == 1)
 343             break;
 344     }
 345     if (i == 5) {
 346         ret = KRB5_KDC_UNREACH;
 347         goto out;
 348     }
 349
 350     ret = process_reply (context,
 351                          auth_context,
 352                          sock,
 353                          result_code,
 354                          result_code_string,
 355                          result_string);
 356
 357 out:
 358     krb5_auth_con_free (context, auth_context);
 359     free (buf);
 360     return ret;
 361 }