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 static const char*
  41 get_env_user(void)
  42 {
  43     const char *user = getenv("USER");
  44     if(user == NULL)
  45         user = getenv("LOGNAME");
  46     if(user == NULL)
  47         user = getenv("USERNAME");
  48     return user;
  49 }
  50
  51 #ifndef _WIN32
  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_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
  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_message(context, ENOTTY,
  89                                    N_("unable to figure out current "
  90                                       "principal", ""));
  91             return ENOTTY; /* XXX */
  92         }
  93         ret = krb5_make_principal(context, princ, NULL, user, NULL);
  94     }
  95     return ret;
  96 }
  97
  98 #else  /* _WIN32 */
  99
 100 #define SECURITY_WIN32
 101 #include <security.h>
 102
 103 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 104 _krb5_get_default_principal_local(krb5_context context,
 105                                   krb5_principal *princ)
 106 {
 107     /* See if we can get the principal first.  We only expect this to
 108        work if logged into a domain. */
 109     {
 110         char username[1024];
 111         ULONG sz = sizeof(username);
 112
 113         if (GetUserNameEx(NameUserPrincipal, username, &sz)) {
 114             return krb5_parse_name_flags(context, username,
 115                                          KRB5_PRINCIPAL_PARSE_ENTERPRISE,
 116                                          princ);
 117         }
 118     }
 119
 120     /* Just get the Windows username.  This should pretty much always
 121        work. */
 122     {
 123         char username[1024];
 124         DWORD dsz = sizeof(username);
 125
 126         if (GetUserName(username, &dsz)) {
 127             return krb5_make_principal(context, princ, NULL, username, NULL);
 128         }
 129     }
 130
 131     /* Failing that, we look at the environment */
 132     {
 133         const char * username = get_env_user();
 134
 135         if (username == NULL) {
 136             krb5_set_error_string(context,
 137                                   "unable to figure out current principal");
 138             return ENOTTY;      /* Really? */
 139         }
 140
 141         return krb5_make_principal(context, princ, NULL, username, NULL);
 142     }
 143 }
 144
 145 #endif
 146
 147 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 148 krb5_get_default_principal (krb5_context context,
 149                             krb5_principal *princ)
 150 {
 151     krb5_error_code ret;
 152     krb5_ccache id;
 153
 154     *princ = NULL;
 155
 156     ret = krb5_cc_default (context, &id);
 157     if (ret == 0) {
 158         ret = krb5_cc_get_principal (context, id, princ);
 159         krb5_cc_close (context, id);
 160         if (ret == 0)
 161             return 0;
 162     }
 163
 164     return _krb5_get_default_principal_local(context, princ);
 165 }