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
|
/*
* security.c: Routines to aid secure uid operations
*
* Copyright (C) 1994, 1995 Graeme W. Wilford. (Wilf.)
* Copyright (C) 2001, 2003, 2004, 2007, 2010, 2011 Colin Watson.
*
* This file is part of man-db.
*
* man-db is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* man-db is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with man-db; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Mon Aug 8 20:35:30 BST 1994 Wilf. (G.Wilford@ee.surrey.ac.uk)
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif /* HAVE_CONFIG_H */
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include "gettext.h"
#define _(String) gettext (String)
#include "manconfig.h"
#include "error.h"
#include "cleanup.h"
#include "pipeline.h"
#include "security.h"
#ifdef MAN_OWNER
/*
* This is the name of the user that the preformatted man pages belong to.
* If you are running man as a setuid program, you should make sure
* that all of the cat pages and the directories that
* they live in are writeable by this user.
*/
# include <pwd.h>
# include <unistd.h>
# include "idpriv.h"
uid_t ruid; /* initial real user id */
uid_t euid; /* initial effective user id */
uid_t uid; /* current euid */
gid_t rgid; /* initial real group id */
gid_t egid; /* initial effective group id */
gid_t gid; /* current egid */
static struct passwd *man_owner;
/* Keep a count of how many times we've dropped privileges, and only regain
* them if regain_effective_privs() is called an equal number of times.
*/
static int priv_drop_count = 0;
static void gripe_set_euid (void)
{
error (FATAL, errno, _("can't set effective uid"));
}
#endif /* MAN_OWNER */
void init_security (void)
{
#ifdef MAN_OWNER
ruid = getuid ();
uid = euid = geteuid ();
debug ("ruid=%d, euid=%d\n", (int) ruid, (int) euid);
rgid = getgid ();
gid = egid = getegid ();
debug ("rgid=%d, egid=%d\n", (int) rgid, (int) egid);
priv_drop_count = 0;
drop_effective_privs ();
#endif /* MAN_OWNER */
}
bool _GL_ATTRIBUTE_PURE running_setuid (void)
{
#ifdef MAN_OWNER
return ruid != euid;
#else /* !MAN_OWNER */
return false;
#endif
}
#ifdef MAN_OWNER
/* Return a pointer to the password entry structure for MAN_OWNER. This
* structure will be statically stored.
*/
struct passwd *get_man_owner (void)
{
if (man_owner)
return man_owner;
man_owner = getpwnam (MAN_OWNER);
if (!man_owner)
error (FAIL, 0, _("the setuid man user \"%s\" does not exist"),
MAN_OWNER);
assert (man_owner);
return man_owner;
}
#endif /* MAN_OWNER */
/*
* function to gain user privs by either (a) dropping effective privs
* completely (saved ids) or (b) reversing euid w/ uid.
* Ignore if superuser.
*/
void drop_effective_privs (void)
{
#ifdef MAN_OWNER
if (uid != ruid) {
debug ("drop_effective_privs()\n");
if (idpriv_temp_drop ())
gripe_set_euid ();
uid = ruid;
gid = rgid;
}
priv_drop_count++;
debug ("++priv_drop_count = %d\n", priv_drop_count);
#endif /* MAN_OWNER */
}
/*
* function to (re)gain setuid privs by (a) setting euid from suid or (b)
* (re)reversing uid w/ euid. Ignore if superuser.
*/
void regain_effective_privs (void)
{
#ifdef MAN_OWNER
if (priv_drop_count) {
priv_drop_count--;
debug ("--priv_drop_count = %d\n", priv_drop_count);
if (priv_drop_count)
return;
}
if (uid != euid) {
debug ("regain_effective_privs()\n");
if (idpriv_temp_restore ())
gripe_set_euid ();
uid = euid;
gid = egid;
}
#endif /* MAN_OWNER */
}
/* Pipeline command pre-exec hook to permanently drop privileges. */
void drop_privs (void *data _GL_UNUSED)
{
#ifdef MAN_OWNER
if (idpriv_drop ())
gripe_set_euid ();
#endif /* MAN_OWNER */
}
|
