lib/krb5/get_default_principal.c

   1 /*
   2  * Copyright (c) 1997 - 2001 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 "krb5_locl.h"
  35
  36 /*
  37  * Try to find out what's a reasonable default principal.
  38  */
  39
  40 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
  41 _krb5_get_default_principal_local (krb5_context context,
  42                                    krb5_principal *princ)
  43 {
  44     const char *user = NULL;
  45     const char *second_component = NULL;
  46     char userbuf[128];
  47
  48     *princ = NULL;
  49
  50     /*
  51      * NOTE: We prefer getlogin_r() (via roken_get_loginname()) to using $USER,
  52      *       $LOGNAME, or getpwuid_r() (via roken_get_username()), in that
  53      *       order, otherwise we won't figure out to output
  54      *       <username>/root@DEFAULT_REALM.
  55      */
  56 #ifndef WIN32
  57     if (geteuid() == 0)
  58         user = roken_get_loginname(userbuf, sizeof(userbuf));
  59 #endif
  60     if (user == NULL)
  61         user = roken_get_username(userbuf, sizeof(userbuf));
  62     if (user == NULL) {
  63         krb5_set_error_message(context, ENOTTY,
  64                                N_("unable to figure out current principal",
  65                                   ""));
  66         return ENOTTY; /* XXX */
  67     }
  68
  69 #ifndef WIN32
  70     if (!issuid() && getuid() == 0 && strcmp(user, "root") != 0)
  71         second_component = "root"; /* We'll use <user>/root */
  72 #endif
  73     return krb5_make_principal(context, princ, NULL, user,
  74                                second_component, NULL);
  75 }
  76
  77 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
  78 krb5_get_default_principal (krb5_context context,
  79                             krb5_principal *princ)
  80 {
  81     krb5_error_code ret;
  82     krb5_ccache id;
  83
  84     *princ = NULL;
  85
  86     ret = krb5_cc_default (context, &id);
  87     if (ret == 0) {
  88         ret = krb5_cc_get_principal (context, id, princ);
  89         krb5_cc_close (context, id);
  90         if (ret == 0)
  91             return 0;
  92     }
  93
  94     return _krb5_get_default_principal_local(context, princ);
  95 }