1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
/*
* $Source$
* $Author$
*
* Copyright 1990 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America is assumed
* to require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* krb5_kuserok()
*/
#if !defined(lint) && !defined(SABER)
static char rcsid_kuserok_c [] =
"$Id$";
#endif /* !lint & !SABER */
#include <krb5/krb5.h>
#include <krb5/osconf.h>
#include <krb5/ext-proto.h>
#include <krb5/los-proto.h>
#include <krb5/sysincl.h>
#include <stdio.h>
#include <pwd.h>
#if defined(_AIX) && defined(_IBMR2)
#include <sys/access.h>
/* xlc has a bug with "const" */
#define getpwnam(user) getpwnam((char *)user)
#endif
#define MAX_USERNAME 10
/*
* Given a Kerberos principal "principal", and a local username "luser",
* determine whether user is authorized to login according to the
* authorization file ("~luser/.klogin" by default). Returns TRUE
* if authorized, FALSE if not authorized.
*
* If there is no account for "luser" on the local machine, returns
* FALSE. If there is no authorization file, and the given Kerberos
* name "server" translates to the same name as "luser" (using
* krb5_aname_to_lname()), returns TRUE. Otherwise, if the authorization file
* can't be accessed, returns FALSE. Otherwise, the file is read for
* a matching principal name, instance, and realm. If one is found,
* returns TRUE, if none is found, returns FALSE.
*
* The file entries are in the format produced by krb5_unparse_name(),
* one entry per line.
*
*/
krb5_boolean
krb5_kuserok(principal, luser)
krb5_principal principal;
const char *luser;
{
struct stat sbuf;
struct passwd *pwd;
char pbuf[MAXPATHLEN];
krb5_boolean isok = FALSE;
FILE *fp;
char kuser[MAX_USERNAME];
char *princname;
char linebuf[BUFSIZ];
char *newline;
int gobble;
/* no account => no access */
if ((pwd = getpwnam(luser)) == NULL) {
return(FALSE);
}
(void) strcpy(pbuf, pwd->pw_dir);
(void) strcat(pbuf, "/.k5login");
if (access(pbuf, F_OK)) { /* not accessible */
/*
* if he's trying to log in as himself, and there is no .klogin file,
* let him. To find out, call
* krb5_aname_to_localname to convert the principal to a name
* which we can string compare.
*/
if (!(krb5_aname_to_localname(principal,
sizeof(kuser), kuser))
&& (strcmp(kuser, luser) == 0)) {
return(TRUE);
}
}
if (krb5_unparse_name(principal, &princname))
return(FALSE); /* no hope of matching */
/* open ~/.klogin */
if ((fp = fopen(pbuf, "r")) == NULL) {
free(princname);
return(FALSE);
}
/*
* security: if the user does not own his own .klogin file,
* do not grant access
*/
if (fstat(fileno(fp), &sbuf)) {
fclose(fp);
free(princname);
return(FALSE);
}
if (sbuf.st_uid != pwd->pw_uid) {
fclose(fp);
free(princname);
return(FALSE);
}
/* check each line */
while (!isok && (fgets(linebuf, BUFSIZ, fp) != NULL)) {
/* null-terminate the input string */
linebuf[BUFSIZ-1] = '\0';
newline = NULL;
/* nuke the newline if it exists */
if (newline = strchr(linebuf, '\n'))
*newline = '\0';
if (!strcmp(linebuf, princname)) {
isok = TRUE;
continue;
}
/* clean up the rest of the line if necessary */
if (!newline)
while (((gobble = getc(fp)) != EOF) && gobble != '\n');
}
free(princname);
fclose(fp);
return(isok);
}
|
