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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/os/kuserok.c */
/*
* Copyright 1990,1993,2007 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* 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. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* 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.
*/
#include "k5-int.h"
#if !defined(_WIN32) /* Not yet for Windows */
#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 65
#if defined(__APPLE__) && defined(__MACH__)
#include <hfs/hfs_mount.h> /* XXX */
#define FILE_OWNER_OK(UID) ((UID) == 0 || (UID) == UNKNOWNUID)
#else
#define FILE_OWNER_OK(UID) ((UID) == 0)
#endif
enum result { ACCEPT, REJECT, PASS };
/*
* Find the k5login filename for luser, either in the user's homedir or in a
* configured directory under the username.
*/
static krb5_error_code
get_k5login_filename(krb5_context context, const char *luser,
const char *homedir, char **filename_out)
{
krb5_error_code ret;
char *dir, *filename;
*filename_out = NULL;
ret = profile_get_string(context->profile, KRB5_CONF_LIBDEFAULTS,
KRB5_CONF_K5LOGIN_DIRECTORY, NULL, NULL, &dir);
if (ret != 0)
return ret;
if (dir == NULL) {
/* Look in the user's homedir. */
if (asprintf(&filename, "%s/.k5login", homedir) < 0)
return ENOMEM;
} else {
/* Look in the configured directory. */
if (asprintf(&filename, "%s/%s", dir, luser) < 0)
ret = ENOMEM;
profile_release_string(dir);
if (ret)
return ret;
}
*filename_out = filename;
return 0;
}
/*
* Determine whether principal is authorized to log in as luser according to
* the user's k5login file. Return ACCEPT if the k5login file authorizes the
* principal, PASS if the k5login file does not exist, or REJECT if the k5login
* file exists but does not authorize the principal. If k5login files are
* configured to be non-authoritative, pass instead of rejecting.
*/
static enum result
k5login_ok(krb5_context context, krb5_principal principal, const char *luser)
{
int authoritative = TRUE, gobble;
enum result result = REJECT;
char *filename = NULL, *princname = NULL;
char *newline, linebuf[BUFSIZ], pwbuf[BUFSIZ];
struct stat sbuf;
struct passwd pwx, *pwd;
FILE *fp = NULL;
if (profile_get_boolean(context->profile, KRB5_CONF_LIBDEFAULTS,
KRB5_CONF_K5LOGIN_AUTHORITATIVE, NULL, TRUE,
&authoritative) != 0)
goto cleanup;
/* Get the local user's homedir and uid. */
if (k5_getpwnam_r(luser, &pwx, pwbuf, sizeof(pwbuf), &pwd) != 0)
goto cleanup;
if (get_k5login_filename(context, luser, pwd->pw_dir, &filename) != 0)
goto cleanup;
if (access(filename, F_OK) != 0) {
result = PASS;
goto cleanup;
}
if (krb5_unparse_name(context, principal, &princname) != 0)
goto cleanup;
fp = fopen(filename, "r");
if (fp == NULL)
goto cleanup;
set_cloexec_file(fp);
/* For security reasons, the .k5login file must be owned either by
* the user or by root. */
if (fstat(fileno(fp), &sbuf))
goto cleanup;
if (sbuf.st_uid != pwd->pw_uid && !FILE_OWNER_OK(sbuf.st_uid))
goto cleanup;
/* Check each line. */
while (result != ACCEPT && (fgets(linebuf, sizeof(linebuf), fp) != NULL)) {
newline = strrchr(linebuf, '\n');
if (newline != NULL)
*newline = '\0';
if (strcmp(linebuf, princname) == 0)
result = ACCEPT;
/* Clean up the rest of the line if necessary. */
if (newline == NULL)
while (((gobble = getc(fp)) != EOF) && gobble != '\n');
}
cleanup:
free(princname);
free(filename);
if (fp != NULL)
fclose(fp);
/* If k5login files are non-authoritative, never reject. */
return (!authoritative && result == REJECT) ? PASS : result;
}
/*
* Determine whether principal is authorized to log in as luser according to
* aname-to-localname translation. Return ACCEPT if principal translates to
* luser or PASS if it does not.
*/
static enum result
an2ln_ok(krb5_context context, krb5_principal principal, const char *luser)
{
krb5_error_code ret;
char kuser[MAX_USERNAME];
ret = krb5_aname_to_localname(context, principal, sizeof(kuser), kuser);
if (ret != 0)
return PASS;
return (strcmp(kuser, luser) == 0) ? ACCEPT : PASS;
}
krb5_boolean KRB5_CALLCONV
krb5_kuserok(krb5_context context, krb5_principal principal, const char *luser)
{
enum result result;
result = k5login_ok(context, principal, luser);
if (result == PASS)
result = an2ln_ok(context, principal, luser);
return (result == ACCEPT) ? TRUE : FALSE;
}
#else /* _WIN32 */
/*
* If the given Kerberos name "server" translates to the same name as "luser"
* (using * krb5_aname_to_lname()), returns TRUE.
*/
krb5_boolean KRB5_CALLCONV
krb5_kuserok(context, principal, luser)
krb5_context context;
krb5_principal principal;
const char *luser;
{
char kuser[50];
if (krb5_aname_to_localname(context, principal, sizeof(kuser), kuser))
return FALSE;
if (strcmp(kuser, luser) == 0)
return TRUE;
return FALSE;
}
#endif /* _WIN32 */
|
