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 static int   add_to_ccache = 0;
  55 static int   use_referral_realm = 0;
  56
  57 static const char *enc_type = "aes256-cts-hmac-sha1-96";
  58 static const char *session_enc_type = NULL;
  59
  60 static void
  61 encode_ticket(krb5_context context,
  62               EncryptionKey *skey,
  63               krb5_enctype etype,
  64               int skvno,
  65               krb5_creds *cred)
  66 {
  67     size_t len, size;
  68     char *buf;
  69     krb5_error_code ret;
  70     krb5_crypto crypto;
  71     EncryptedData enc_part;
  72     EncTicketPart et;
  73     Ticket ticket;
  74
  75     memset(&enc_part, 0, sizeof(enc_part));
  76     memset(&ticket, 0, sizeof(ticket));
  77
  78     /*
  79      * Set up `enc_part'
  80      */
  81
  82     et.flags = cred->flags.b;
  83     et.key = cred->session;
  84     et.crealm = cred->client->realm;
  85     et.cname = cred->client->name;
  86     {
  87         krb5_data empty_string;
  88
  89         krb5_data_zero(&empty_string);
  90         et.transited.tr_type = domain_X500_Compress;
  91         et.transited.contents = empty_string;
  92     }
  93     et.authtime = cred->times.authtime;
  94     et.starttime = NULL;
  95     et.endtime = cred->times.endtime;
  96     et.renew_till = NULL;
  97     et.caddr = &cred->addresses;
  98     et.authorization_data = NULL; /* XXX allow random authorization_data */
  99
 100     /*
 101      * Encrypt `enc_part' of ticket with service key
 102      */
 103
 104     ASN1_MALLOC_ENCODE(EncTicketPart, buf, len, &et, &size, ret);
 105     if (ret)
 106         krb5_err(context, 1, ret, "EncTicketPart");
 107
 108     ret = krb5_crypto_init(context, skey, etype, &crypto);
 109     if (ret)
 110         krb5_err(context, 1, ret, "krb5_crypto_init");
 111     ret = krb5_encrypt_EncryptedData(context,
 112                                       crypto,
 113                                       KRB5_KU_TICKET,
 114                                       buf,
 115                                       len,
 116                                       skvno,
 117                                       &ticket.enc_part);
 118     if (ret)
 119         krb5_err(context, 1, ret, "krb5_encrypt_EncryptedData");
 120
 121     free(buf);
 122     krb5_crypto_destroy(context, crypto);
 123
 124     /*
 125      * Encode ticket
 126      */
 127
 128     ticket.tkt_vno = 5;
 129     ticket.realm = cred->server->realm;
 130     ticket.sname = cred->server->name;
 131     ASN1_MALLOC_ENCODE(Ticket, cred->ticket.data, cred->ticket.length, &ticket, &size, ret);
 132     free_EncryptedData(&ticket.enc_part);
 133     if(ret)
 134         krb5_err(context, 1, ret, "encode_Ticket");
 135 }
 136
 137 /*
 138  *
 139  */
 140
 141 static int
 142 create_krb5_tickets(krb5_context context, krb5_keytab kt)
 143 {
 144     krb5_error_code ret;
 145     krb5_keytab_entry entry;
 146     krb5_creds cred;
 147     krb5_enctype etype;
 148     krb5_enctype session_etype;
 149     krb5_ccache ccache;
 150
 151     memset(&cred, 0, sizeof(cred));
 152
 153     ret = krb5_string_to_enctype(context, enc_type, &etype);
 154     if (ret)
 155         krb5_err (context, 1, ret, "krb5_string_to_enctype (enc-type)");
 156     ret = krb5_string_to_enctype(context, session_enc_type, &session_etype);
 157     if (ret)
 158         krb5_err (context, 1, ret, "krb5_string_to_enctype (session-enc-type)");
 159     ret = krb5_kt_get_entry(context, kt, server_principal, 0, etype, &entry);
 160     if (ret)
 161         krb5_err(context, 1, ret, "krb5_kt_get_entry (perhaps use different --enc-type)");
 162
 163     /*
 164      * setup cred
 165      */
 166
 167
 168     ret = krb5_copy_principal(context, client_principal, &cred.client);
 169     if (ret)
 170         krb5_err(context, 1, ret, "krb5_copy_principal");
 171     ret = krb5_copy_principal(context, server_principal, &cred.server);
 172     if (ret)
 173         krb5_err(context, 1, ret, "krb5_copy_principal");
 174     krb5_generate_random_keyblock(context, session_etype, &cred.session);
 175
 176     cred.times.authtime = time(NULL);
 177     cred.times.starttime = time(NULL);
 178     cred.times.endtime = time(NULL) + expiration_time;
 179     cred.times.renew_till = 0;
 180     krb5_data_zero(&cred.second_ticket);
 181
 182     ret = krb5_get_all_client_addrs(context, &cred.addresses);
 183     if (ret)
 184         krb5_err(context, 1, ret, "krb5_get_all_client_addrs");
 185     cred.flags.b = ticket_flags;
 186
 187
 188     /*
 189      * Encode encrypted part of ticket
 190      */
 191
 192     encode_ticket(context, &entry.keyblock, etype, entry.vno, &cred);
 193     krb5_kt_free_entry(context, &entry);
 194
 195     /*
 196      * Write to cc
 197      */
 198
 199     if (ccache_str) {
 200         ret = krb5_cc_resolve(context, ccache_str, &ccache);
 201         if (ret)
 202             krb5_err(context, 1, ret, "krb5_cc_resolve");
 203     } else {
 204         ret = krb5_cc_default(context, &ccache);
 205         if (ret)
 206             krb5_err(context, 1, ret, "krb5_cc_default");
 207     }
 208
 209     if (add_to_ccache) {
 210         krb5_principal def_princ = NULL;
 211
 212         /*
 213          * Force fcache to read the ccache header, otherwise the store
 214          * will fail.
 215          */
 216         ret = krb5_cc_get_principal(context, ccache, &def_princ);
 217         if (ret) {
 218             krb5_warn(context, ret,
 219                       "Given ccache appears not to exist; initializing it");
 220             ret = krb5_cc_initialize(context, ccache, cred.client);
 221             if (ret)
 222                 krb5_err(context, 1, ret, "krb5_cc_initialize");
 223         }
 224         krb5_free_principal(context, def_princ);
 225     } else {
 226         ret = krb5_cc_initialize(context, ccache, cred.client);
 227         if (ret)
 228             krb5_err(context, 1, ret, "krb5_cc_initialize");
 229     }
 230
 231     if (use_referral_realm &&
 232         strcmp(krb5_principal_get_realm(context, cred.server), "") != 0) {
 233         krb5_free_principal(context, cred.server);
 234         ret = krb5_copy_principal(context, server_principal, &cred.server);
 235         if (ret)
 236             krb5_err(context, 1, ret, "krb5_copy_principal");
 237         ret = krb5_principal_set_realm(context, cred.server, "");
 238         if (ret)
 239             krb5_err(context, 1, ret, "krb5_principal_set_realm");
 240         ret = krb5_cc_store_cred(context, ccache, &cred);
 241         if (ret)
 242             krb5_err(context, 1, ret, "krb5_cc_store_cred");
 243
 244         krb5_free_principal(context, cred.server);
 245         ret = krb5_copy_principal(context, server_principal, &cred.server);
 246         if (ret)
 247             krb5_err(context, 1, ret, "krb5_copy_principal");
 248     }
 249     ret = krb5_cc_store_cred(context, ccache, &cred);
 250     if (ret)
 251         krb5_err(context, 1, ret, "krb5_cc_store_cred");
 252
 253     krb5_free_cred_contents(context, &cred);
 254     krb5_cc_close(context, ccache);
 255
 256     return 0;
 257 }
 258
 259 /*
 260  *
 261  */
 262
 263 static void
 264 setup_env(krb5_context context, krb5_keytab *kt)
 265 {
 266     krb5_error_code ret;
 267
 268     if (keytab_file)
 269         ret = krb5_kt_resolve(context, keytab_file, kt);
 270     else
 271         ret = krb5_kt_default(context, kt);
 272     if (ret)
 273         krb5_err(context, 1, ret, "resolving keytab");
 274
 275     if (client_principal_str == NULL)
 276         krb5_errx(context, 1, "missing client principal");
 277     ret = krb5_parse_name(context, client_principal_str, &client_principal);
 278     if (ret)
 279         krb5_err(context, 1, ret, "resolvning client name");
 280
 281     if (server_principal_str == NULL)
 282         krb5_errx(context, 1, "missing server principal");
 283     ret = krb5_parse_name(context, server_principal_str, &server_principal);
 284     if (ret)
 285         krb5_err(context, 1, ret, "resolvning server name");
 286
 287     /* If no session-enc-type specified on command line and this is an afs */
 288     /* service ticket, change default of session_enc_type to DES.       */
 289     if (session_enctype_string == NULL
 290         && strcmp("afs", *server_principal->name.name_string.val) == 0)
 291         session_enc_type = "des-cbc-crc";
 292
 293     if (ticket_flags_str) {
 294         int ticket_flags_int;
 295
 296         ticket_flags_int = parse_flags(ticket_flags_str,
 297                                        asn1_TicketFlags_units(), 0);
 298         if (ticket_flags_int <= 0) {
 299             krb5_warnx(context, "bad ticket flags: `%s'", ticket_flags_str);
 300             print_flags_table(asn1_TicketFlags_units(), stderr);
 301             exit(1);
 302         }
 303         if (ticket_flags_int)
 304             ticket_flags = int2TicketFlags(ticket_flags_int);
 305     }
 306 }
 307
 308 /*
 309  *
 310  */
 311
 312 struct getargs args[] = {
 313     { "ccache", 0, arg_string, &ccache_str,
 314       "name of kerberos 5 credential cache", "cache-name"},
 315     { "server", 's', arg_string, &server_principal_str,
 316       "name of server principal", NULL },
 317     { "client", 'c', arg_string, &client_principal_str,
 318       "name of client principal", NULL },
 319     { "keytab", 'k', arg_string, &keytab_file,
 320       "name of keytab file", NULL },
 321     { "krb5", '5', arg_flag,     &use_krb5,
 322       "create a kerberos 5 ticket", NULL },
 323     { "add", 'A', arg_flag,      &add_to_ccache,
 324       "add to ccache without re-initializing it", NULL },
 325     { "referral", 'R', arg_flag,         &use_referral_realm,
 326       "store an additional entry for the service with the empty realm", NULL },
 327     { "expire-time", 'e', arg_integer, &expiration_time,
 328       "lifetime of ticket in seconds", NULL },
 329     { "client-addresses", 'a', arg_strings, &client_addresses,
 330       "addresses of client", NULL },
 331     { "enc-type", 't', arg_string,      &enctype_string,
 332       "encryption type", NULL },
 333     { "session-enc-type", 0, arg_string,&session_enctype_string,
 334       "encryption type", NULL },
 335     { "ticket-flags", 'f', arg_string,   &ticket_flags_str,
 336       "ticket flags for krb5 ticket", NULL },
 337     { "version", 0,  arg_flag,          &version_flag,  "Print version",
 338       NULL },
 339     { "help",    0,  arg_flag,          &help_flag,     NULL,
 340       NULL }
 341 };
 342
 343 static void
 344 usage(int ret)
 345 {
 346     arg_printusage(args,
 347                    sizeof(args) / sizeof(args[0]),
 348                    NULL,
 349                    "");
 350     exit(ret);
 351 }
 352
 353 int
 354 main(int argc, char **argv)
 355 {
 356     int optidx = 0;
 357     krb5_error_code ret;
 358     krb5_context context;
 359     krb5_keytab kt;
 360
 361     setprogname(argv[0]);
 362
 363     ret = krb5_init_context(&context);
 364     if (ret)
 365         errx(1, "krb5_init_context failed: %u", ret);
 366
 367     if (getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optidx))
 368         usage(1);
 369
 370     if (help_flag)
 371         usage(0);
 372
 373     if (version_flag) {
 374         print_version(NULL);
 375         return 0;
 376     }
 377
 378     if (enctype_string)
 379         enc_type = enctype_string;
 380     if (session_enctype_string)
 381         session_enc_type = session_enctype_string;
 382     else
 383         session_enc_type = enc_type;
 384
 385     setup_env(context, &kt);
 386
 387     if (use_krb5)
 388         create_krb5_tickets(context, kt);
 389
 390     krb5_kt_close(context, kt);
 391     krb5_free_context(context);
 392
 393     return 0;
 394 }