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 RCSID("$Id$");
  37
  38 /*
  39  * Try to find out what's a reasonable default principal.
  40  */
  41
  42 static const char*
  43 get_env_user(void)
  44 {
  45     const char *user = getenv("USER");
  46     if(user == NULL)
  47         user = getenv("LOGNAME");
  48     if(user == NULL)
  49         user = getenv("USERNAME");
  50     return user;
  51 }
  52
  53 /*
  54  * Will only use operating-system dependant operation to get the
  55  * default principal, for use of functions that in ccache layer to
  56  * avoid recursive calls.
  57  */
  58
  59 krb5_error_code
  60 _krb5_get_default_principal_local (krb5_context context,
  61                                    krb5_principal *princ)
  62 {
  63     krb5_error_code ret;
  64     const char *user;
  65     uid_t uid;
  66
  67     *princ = NULL;
  68
  69     uid = getuid();
  70     if(uid == 0) {
  71         user = getlogin();
  72         if(user == NULL)
  73             user = get_env_user();
  74         if(user != NULL && strcmp(user, "root") != 0)
  75             ret = krb5_make_principal(context, princ, NULL, user, "root", NULL);
  76         else
  77             ret = krb5_make_principal(context, princ, NULL, "root", NULL);
  78     } else {
  79         struct passwd *pw = getpwuid(uid);
  80         if(pw != NULL)
  81             user = pw->pw_name;
  82         else {
  83             user = get_env_user();
  84             if(user == NULL)
  85                 user = getlogin();
  86         }
  87         if(user == NULL) {
  88             krb5_set_error_string(context,
  89                                   "unable to figure out current principal");
  90             return ENOTTY; /* XXX */
  91         }
  92         ret = krb5_make_principal(context, princ, NULL, user, NULL);
  93     }
  94     return ret;
  95 }
  96
  97 krb5_error_code KRB5_LIB_FUNCTION
  98 krb5_get_default_principal (krb5_context context,
  99                             krb5_principal *princ)
 100 {
 101     krb5_error_code ret;
 102     krb5_ccache id;
 103
 104     *princ = NULL;
 105
 106     ret = krb5_cc_default (context, &id);
 107     if (ret == 0) {
 108         ret = krb5_cc_get_principal (context, id, princ);
 109         krb5_cc_close (context, id);
 110         if (ret == 0)
 111             return 0;
 112     }
 113
 114     return _krb5_get_default_principal_local(context, princ);
 115 }