kuser/kimpersonate.c

   1 /*
   2  * Copyright (c) 2000 - 2007 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. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "kuser_locl.h"
  35 #include <parse_units.h>
  36
  37 static char *client_principal_str = NULL;
  38 static krb5_principal client_principal;
  39 static char *server_principal_str = NULL;
  40 static krb5_principal server_principal;
  41
  42 static char *ccache_str = NULL;
  43
  44 static char *ticket_flags_str = NULL;
  45 static TicketFlags ticket_flags;
  46 static char *keytab_file = NULL;
  47 static char *enctype_string = NULL;
  48 static char *session_enctype_string = NULL;
  49 static int   expiration_time = 3600;
  50 static struct getarg_strings client_addresses;
  51 static int   version_flag = 0;
  52 static int   help_flag = 0;
  53 static int   use_krb5 = 1;
  54
  55 static const char *enc_type = "aes256-cts-hmac-sha1-96";
  56 static const char *session_enc_type = NULL;
  57
  58 static void
  59 encode_ticket (krb5_context context,
  60                EncryptionKey *skey,
  61                krb5_enctype etype,
  62                int skvno,
  63                krb5_creds *cred)
  64 {
  65     size_t len, size;
  66     char *buf;
  67     krb5_error_code ret;
  68     krb5_crypto crypto;
  69     EncryptedData enc_part;
  70     EncTicketPart et;
  71     Ticket ticket;
  72
  73     memset (&enc_part, 0, sizeof(enc_part));
  74     memset (&ticket, 0, sizeof(ticket));
  75
  76     /*
  77      * Set up `enc_part'
  78      */
  79
  80     et.flags = cred->flags.b;
  81     et.key = cred->session;
  82     et.crealm = cred->client->realm;
  83     copy_PrincipalName(&cred->client->name, &et.cname);
  84     {
  85         krb5_data empty_string;
  86
  87         krb5_data_zero(&empty_string);
  88         et.transited.tr_type = DOMAIN_X500_COMPRESS;
  89         et.transited.contents = empty_string;
  90     }
  91     et.authtime = cred->times.authtime;
  92     et.starttime = NULL;
  93     et.endtime = cred->times.endtime;
  94     et.renew_till = NULL;
  95     et.caddr = &cred->addresses;
  96     et.authorization_data = NULL; /* XXX allow random authorization_data */
  97
  98     /*
  99      * Encrypt `enc_part' of ticket with service key
 100      */
 101
 102     ASN1_MALLOC_ENCODE(EncTicketPart, buf, len, &et, &size, ret);
 103     if (ret)
 104         krb5_err(context, 1, ret, "EncTicketPart");
 105
 106     ret = krb5_crypto_init(context, skey, etype, &crypto);
 107     if (ret)
 108         krb5_err(context, 1, ret, "krb5_crypto_init");
 109     ret = krb5_encrypt_EncryptedData (context,
 110                                       crypto,
 111                                       KRB5_KU_TICKET,
 112                                       buf,
 113                                       len,
 114                                       skvno,
 115                                       &ticket.enc_part);
 116     if (ret)
 117         krb5_err(context, 1, ret, "krb5_encrypt_EncryptedData");
 118
 119     free(buf);
 120     krb5_crypto_destroy(context, crypto);
 121
 122     /*
 123      * Encode ticket
 124      */
 125
 126     ticket.tkt_vno = 5;
 127     ticket.realm = cred->server->realm;
 128     copy_PrincipalName(&cred->server->name, &ticket.sname);
 129
 130     ASN1_MALLOC_ENCODE(Ticket, buf, len, &ticket, &size, ret);
 131     if(ret)
 132         krb5_err (context, 1, ret, "encode_Ticket");
 133
 134     krb5_data_copy(&cred->ticket, buf, len);
 135     free(buf);
 136 }
 137
 138 /*
 139  *
 140  */
 141
 142 static int
 143 create_krb5_tickets (krb5_context context, krb5_keytab kt)
 144 {
 145     krb5_error_code ret;
 146     krb5_keytab_entry entry;
 147     krb5_creds cred;
 148     krb5_enctype etype;
 149     krb5_enctype session_etype;
 150     krb5_ccache ccache;
 151
 152     memset (&cred, 0, sizeof(cred));
 153
 154     ret = krb5_string_to_enctype (context, enc_type, &etype);
 155     if (ret)
 156         krb5_err (context, 1, ret, "krb5_string_to_enctype (enc-type)");
 157     ret = krb5_string_to_enctype (context, session_enc_type, &session_etype);
 158     if (ret)
 159         krb5_err (context, 1, ret, "krb5_string_to_enctype (session-enc-type)");
 160     ret = krb5_kt_get_entry (context, kt, server_principal,
 161                              0, etype, &entry);
 162     if (ret)
 163         krb5_err (context, 1, ret, "krb5_kt_get_entry");
 164
 165     /*
 166      * setup cred
 167      */
 168
 169
 170     ret = krb5_copy_principal (context, client_principal, &cred.client);
 171     if (ret)
 172         krb5_err (context, 1, ret, "krb5_copy_principal");
 173     ret = krb5_copy_principal (context, server_principal, &cred.server);
 174     if (ret)
 175         krb5_err (context, 1, ret, "krb5_copy_principal");
 176     krb5_generate_random_keyblock(context, session_etype, &cred.session);
 177
 178     cred.times.authtime = time(NULL);
 179     cred.times.starttime = time(NULL);
 180     cred.times.endtime = time(NULL) + expiration_time;
 181     cred.times.renew_till = 0;
 182     krb5_data_zero(&cred.second_ticket);
 183
 184     ret = krb5_get_all_client_addrs (context, &cred.addresses);
 185     if (ret)
 186         krb5_err (context, 1, ret, "krb5_get_all_client_addrs");
 187     cred.flags.b = ticket_flags;
 188
 189
 190     /*
 191      * Encode encrypted part of ticket
 192      */
 193
 194     encode_ticket (context, &entry.keyblock, etype, entry.vno, &cred);
 195
 196     /*
 197      * Write to cc
 198      */
 199
 200     if (ccache_str) {
 201         ret = krb5_cc_resolve(context, ccache_str, &ccache);
 202         if (ret)
 203             krb5_err (context, 1, ret, "krb5_cc_resolve");
 204     } else {
 205         ret = krb5_cc_default (context, &ccache);
 206         if (ret)
 207             krb5_err (context, 1, ret, "krb5_cc_default");
 208     }
 209
 210     ret = krb5_cc_initialize (context, ccache, cred.client);
 211     if (ret)
 212         krb5_err (context, 1, ret, "krb5_cc_initialize");
 213
 214     ret = krb5_cc_store_cred (context, ccache, &cred);
 215     if (ret)
 216         krb5_err (context, 1, ret, "krb5_cc_store_cred");
 217
 218     krb5_free_cred_contents (context, &cred);
 219     krb5_cc_close (context, ccache);
 220
 221     return 0;
 222 }
 223
 224 /*
 225  *
 226  */
 227
 228 static void
 229 setup_env (krb5_context context, krb5_keytab *kt)
 230 {
 231     krb5_error_code ret;
 232
 233     if (keytab_file)
 234         ret = krb5_kt_resolve (context, keytab_file, kt);
 235     else
 236         ret = krb5_kt_default (context, kt);
 237     if (ret)
 238         krb5_err (context, 1, ret, "resolving keytab");
 239
 240     if (client_principal_str == NULL)
 241         krb5_errx (context, 1, "missing client principal");
 242     ret = krb5_parse_name (context, client_principal_str, &client_principal);
 243     if (ret)
 244         krb5_err (context, 1, ret, "resolvning client name");
 245
 246     if (server_principal_str == NULL)
 247         krb5_errx (context, 1, "missing server principal");
 248     ret = krb5_parse_name (context, server_principal_str, &server_principal);
 249     if (ret)
 250         krb5_err (context, 1, ret, "resolvning server name");
 251
 252     /* If no session-enc-type specified on command line and this is an afs */
 253     /* service ticket, change default of session_enc_type to DES.       */
 254     if (session_enctype_string == NULL
 255         && strcmp("afs", *server_principal->name.name_string.val) == 0)
 256         session_enc_type = "des-cbc-crc";
 257
 258     if (ticket_flags_str) {
 259         int ticket_flags_int;
 260
 261         ticket_flags_int = parse_flags(ticket_flags_str,
 262                                        asn1_TicketFlags_units(), 0);
 263         if (ticket_flags_int <= 0) {
 264             krb5_warnx (context, "bad ticket flags: `%s'", ticket_flags_str);
 265             print_flags_table (asn1_TicketFlags_units(), stderr);
 266             exit (1);
 267         }
 268         if (ticket_flags_int)
 269             ticket_flags = int2TicketFlags (ticket_flags_int);
 270     }
 271 }
 272
 273 /*
 274  *
 275  */
 276
 277 struct getargs args[] = {
 278     { "ccache", 0, arg_string, &ccache_str,
 279       "name of kerberos 5 credential cache", "cache-name"},
 280     { "server", 's', arg_string, &server_principal_str,
 281       "name of server principal", NULL },
 282     { "client", 'c', arg_string, &client_principal_str,
 283       "name of client principal", NULL },
 284     { "keytab", 'k', arg_string, &keytab_file,
 285       "name of keytab file", NULL },
 286     { "krb5", '5', arg_flag,     &use_krb5,
 287       "create a kerberos 5 ticket", NULL },
 288     { "expire-time", 'e', arg_integer, &expiration_time,
 289       "lifetime of ticket in seconds", NULL },
 290     { "client-addresses", 'a', arg_strings, &client_addresses,
 291       "addresses of client", NULL },
 292     { "enc-type", 't', arg_string,      &enctype_string,
 293       "encryption type", NULL },
 294     { "session-enc-type", 0, arg_string,&session_enctype_string,
 295       "encryption type", NULL },
 296     { "ticket-flags", 'f', arg_string,   &ticket_flags_str,
 297       "ticket flags for krb5 ticket", NULL },
 298     { "version", 0,  arg_flag,          &version_flag,  "Print version",
 299       NULL },
 300     { "help",    0,  arg_flag,          &help_flag,     NULL,
 301       NULL }
 302 };
 303
 304 static void
 305 usage (int ret)
 306 {
 307     arg_printusage (args,
 308                     sizeof(args) / sizeof(args[0]),
 309                     NULL,
 310                     "");
 311     exit (ret);
 312 }
 313
 314 int
 315 main (int argc, char **argv)
 316 {
 317     int optidx = 0;
 318     krb5_error_code ret;
 319     krb5_context context;
 320     krb5_keytab kt;
 321
 322     setprogname (argv[0]);
 323
 324     ret = krb5_init_context (&context);
 325     if (ret)
 326         errx(1, "krb5_init_context failed: %u", ret);
 327
 328     if (getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optidx))
 329         usage(1);
 330
 331     if (help_flag)
 332         usage(0);
 333
 334     if (version_flag) {
 335         print_version(NULL);
 336         return 0;
 337     }
 338
 339     if (enctype_string)
 340         enc_type = enctype_string;
 341     if (session_enctype_string)
 342         session_enc_type = session_enctype_string;
 343     else
 344         session_enc_type = enc_type;
 345
 346     setup_env(context, &kt);
 347
 348     if (use_krb5)
 349         create_krb5_tickets(context, kt);
 350
 351     krb5_kt_close(context, kt);
 352
 353     return 0;
 354 }