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     copy_PrincipalName(&cred->client->name, &et.cname);
  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     copy_PrincipalName(&cred->server->name, &ticket.sname);
 131
 132     ASN1_MALLOC_ENCODE(Ticket, buf, len, &ticket, &size, ret);
 133     if(ret)
 134         krb5_err(context, 1, ret, "encode_Ticket");
 135
 136     krb5_data_copy(&cred->ticket, buf, len);
 137     free(buf);
 138 }
 139
 140 /*
 141  *
 142  */
 143
 144 static int
 145 create_krb5_tickets(krb5_context context, krb5_keytab kt)
 146 {
 147     krb5_error_code ret;
 148     krb5_keytab_entry entry;
 149     krb5_creds cred;
 150     krb5_enctype etype;
 151     krb5_enctype session_etype;
 152     krb5_ccache ccache;
 153
 154     memset(&cred, 0, sizeof(cred));
 155
 156     ret = krb5_string_to_enctype(context, enc_type, &etype);
 157     if (ret)
 158         krb5_err (context, 1, ret, "krb5_string_to_enctype (enc-type)");
 159     ret = krb5_string_to_enctype(context, session_enc_type, &session_etype);
 160     if (ret)
 161         krb5_err (context, 1, ret, "krb5_string_to_enctype (session-enc-type)");
 162     ret = krb5_kt_get_entry(context, kt, server_principal, 0, etype, &entry);
 163     if (ret)
 164         krb5_err(context, 1, ret, "krb5_kt_get_entry (perhaps use different --enc-type)");
 165
 166     /*
 167      * setup cred
 168      */
 169
 170
 171     ret = krb5_copy_principal(context, client_principal, &cred.client);
 172     if (ret)
 173         krb5_err(context, 1, ret, "krb5_copy_principal");
 174     ret = krb5_copy_principal(context, server_principal, &cred.server);
 175     if (ret)
 176         krb5_err(context, 1, ret, "krb5_copy_principal");
 177     krb5_generate_random_keyblock(context, session_etype, &cred.session);
 178
 179     cred.times.authtime = time(NULL);
 180     cred.times.starttime = time(NULL);
 181     cred.times.endtime = time(NULL) + expiration_time;
 182     cred.times.renew_till = 0;
 183     krb5_data_zero(&cred.second_ticket);
 184
 185     ret = krb5_get_all_client_addrs(context, &cred.addresses);
 186     if (ret)
 187         krb5_err(context, 1, ret, "krb5_get_all_client_addrs");
 188     cred.flags.b = ticket_flags;
 189
 190
 191     /*
 192      * Encode encrypted part of ticket
 193      */
 194
 195     encode_ticket(context, &entry.keyblock, etype, entry.vno, &cred);
 196     krb5_kt_free_entry(context, &entry);
 197
 198     /*
 199      * Write to cc
 200      */
 201
 202     if (ccache_str) {
 203         ret = krb5_cc_resolve(context, ccache_str, &ccache);
 204         if (ret)
 205             krb5_err(context, 1, ret, "krb5_cc_resolve");
 206     } else {
 207         ret = krb5_cc_default(context, &ccache);
 208         if (ret)
 209             krb5_err(context, 1, ret, "krb5_cc_default");
 210     }
 211
 212     if (add_to_ccache) {
 213         krb5_principal def_princ;
 214
 215         /*
 216          * Force fcache to read the ccache header, otherwise the store
 217          * will fail.
 218          */
 219         ret = krb5_cc_get_principal(context, ccache, &def_princ);
 220         if (ret) {
 221             krb5_warn(context, ret,
 222                       "Given ccache appears not to exist; initializing it");
 223             ret = krb5_cc_initialize(context, ccache, cred.client);
 224             if (ret)
 225                 krb5_err(context, 1, ret, "krb5_cc_initialize");
 226         }
 227         krb5_free_principal(context, def_princ);
 228     } else {
 229         ret = krb5_cc_initialize(context, ccache, cred.client);
 230         if (ret)
 231             krb5_err(context, 1, ret, "krb5_cc_initialize");
 232     }
 233
 234     if (use_referral_realm &&
 235         strcmp(krb5_principal_get_realm(context, cred.server), "") != 0) {
 236         krb5_free_principal(context, cred.server);
 237         ret = krb5_copy_principal(context, server_principal, &cred.server);
 238         if (ret)
 239             krb5_err(context, 1, ret, "krb5_copy_principal");
 240         ret = krb5_principal_set_realm(context, cred.server, "");
 241         if (ret)
 242             krb5_err(context, 1, ret, "krb5_principal_set_realm");
 243         ret = krb5_cc_store_cred(context, ccache, &cred);
 244         if (ret)
 245             krb5_err(context, 1, ret, "krb5_cc_store_cred");
 246
 247         krb5_free_principal(context, cred.server);
 248         ret = krb5_copy_principal(context, server_principal, &cred.server);
 249         if (ret)
 250             krb5_err(context, 1, ret, "krb5_copy_principal");
 251     }
 252     ret = krb5_cc_store_cred(context, ccache, &cred);
 253     if (ret)
 254         krb5_err(context, 1, ret, "krb5_cc_store_cred");
 255
 256     krb5_free_cred_contents(context, &cred);
 257     krb5_cc_close(context, ccache);
 258
 259     return 0;
 260 }
 261
 262 /*
 263  *
 264  */
 265
 266 static void
 267 setup_env(krb5_context context, krb5_keytab *kt)
 268 {
 269     krb5_error_code ret;
 270
 271     if (keytab_file)
 272         ret = krb5_kt_resolve(context, keytab_file, kt);
 273     else
 274         ret = krb5_kt_default(context, kt);
 275     if (ret)
 276         krb5_err(context, 1, ret, "resolving keytab");
 277
 278     if (client_principal_str == NULL)
 279         krb5_errx(context, 1, "missing client principal");
 280     ret = krb5_parse_name(context, client_principal_str, &client_principal);
 281     if (ret)
 282         krb5_err(context, 1, ret, "resolvning client name");
 283
 284     if (server_principal_str == NULL)
 285         krb5_errx(context, 1, "missing server principal");
 286     ret = krb5_parse_name(context, server_principal_str, &server_principal);
 287     if (ret)
 288         krb5_err(context, 1, ret, "resolvning server name");
 289
 290     /* If no session-enc-type specified on command line and this is an afs */
 291     /* service ticket, change default of session_enc_type to DES.       */
 292     if (session_enctype_string == NULL
 293         && strcmp("afs", *server_principal->name.name_string.val) == 0)
 294         session_enc_type = "des-cbc-crc";
 295
 296     if (ticket_flags_str) {
 297         int ticket_flags_int;
 298
 299         ticket_flags_int = parse_flags(ticket_flags_str,
 300                                        asn1_TicketFlags_units(), 0);
 301         if (ticket_flags_int <= 0) {
 302             krb5_warnx(context, "bad ticket flags: `%s'", ticket_flags_str);
 303             print_flags_table(asn1_TicketFlags_units(), stderr);
 304             exit(1);
 305         }
 306         if (ticket_flags_int)
 307             ticket_flags = int2TicketFlags(ticket_flags_int);
 308     }
 309 }
 310
 311 /*
 312  *
 313  */
 314
 315 struct getargs args[] = {
 316     { "ccache", 0, arg_string, &ccache_str,
 317       "name of kerberos 5 credential cache", "cache-name"},
 318     { "server", 's', arg_string, &server_principal_str,
 319       "name of server principal", NULL },
 320     { "client", 'c', arg_string, &client_principal_str,
 321       "name of client principal", NULL },
 322     { "keytab", 'k', arg_string, &keytab_file,
 323       "name of keytab file", NULL },
 324     { "krb5", '5', arg_flag,     &use_krb5,
 325       "create a kerberos 5 ticket", NULL },
 326     { "add", 'A', arg_flag,      &add_to_ccache,
 327       "add to ccache without re-initializing it", NULL },
 328     { "referral", 'R', arg_flag,         &use_referral_realm,
 329       "store an additional entry for the service with the empty realm", NULL },
 330     { "expire-time", 'e', arg_integer, &expiration_time,
 331       "lifetime of ticket in seconds", NULL },
 332     { "client-addresses", 'a', arg_strings, &client_addresses,
 333       "addresses of client", NULL },
 334     { "enc-type", 't', arg_string,      &enctype_string,
 335       "encryption type", NULL },
 336     { "session-enc-type", 0, arg_string,&session_enctype_string,
 337       "encryption type", NULL },
 338     { "ticket-flags", 'f', arg_string,   &ticket_flags_str,
 339       "ticket flags for krb5 ticket", NULL },
 340     { "version", 0,  arg_flag,          &version_flag,  "Print version",
 341       NULL },
 342     { "help",    0,  arg_flag,          &help_flag,     NULL,
 343       NULL }
 344 };
 345
 346 static void
 347 usage(int ret)
 348 {
 349     arg_printusage(args,
 350                    sizeof(args) / sizeof(args[0]),
 351                    NULL,
 352                    "");
 353     exit(ret);
 354 }
 355
 356 int
 357 main(int argc, char **argv)
 358 {
 359     int optidx = 0;
 360     krb5_error_code ret;
 361     krb5_context context;
 362     krb5_keytab kt;
 363
 364     setprogname(argv[0]);
 365
 366     ret = krb5_init_context(&context);
 367     if (ret)
 368         errx(1, "krb5_init_context failed: %u", ret);
 369
 370     if (getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optidx))
 371         usage(1);
 372
 373     if (help_flag)
 374         usage(0);
 375
 376     if (version_flag) {
 377         print_version(NULL);
 378         return 0;
 379     }
 380
 381     if (enctype_string)
 382         enc_type = enctype_string;
 383     if (session_enctype_string)
 384         session_enc_type = session_enctype_string;
 385     else
 386         session_enc_type = enc_type;
 387
 388     setup_env(context, &kt);
 389
 390     if (use_krb5)
 391         create_krb5_tickets(context, kt);
 392
 393     krb5_kt_close(context, kt);
 394
 395     return 0;
 396 }