xref: /freebsd/crypto/heimdal/lib/krb5/get_default_principal.c (revision ae77177087c655fc883075af4f425b37e032cd05)
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_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_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_error_code
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 }
166