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
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/* ufopen.c
Open a file with the permissions of the invoking user.
Copyright (C) 1992 Ian Lance Taylor
This file is part of the Taylor UUCP package.
This program 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.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
The author of the program may be contacted at ian@airs.com or
c/o Cygnus Support, Building 200, 1 Kendall Square, Cambridge, MA 02139.
*/
#include "uucp.h"
#include "uudefs.h"
#include "sysdep.h"
#include "system.h"
#include <errno.h>
#if HAVE_FCNTL_H
#include <fcntl.h>
#else
#if HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#endif
#ifndef O_RDONLY
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#endif
#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif
#ifndef FD_CLOEXEC
#define FD_CLOEXEC 1
#endif
/* Local functions. */
static boolean fsuser_perms P((uid_t *pieuid));
static boolean fsuucp_perms P((long ieuid));
/* Switch to permissions of the invoking user. */
static boolean
fsuser_perms (pieuid)
uid_t *pieuid;
{
uid_t ieuid, iuid;
ieuid = geteuid ();
iuid = getuid ();
if (pieuid != NULL)
*pieuid = ieuid;
#if HAVE_SETREUID
/* Swap the effective user id and the real user id. We can then
swap them back again when we want to return to the uucp user's
permissions. */
if (setreuid (ieuid, iuid) < 0)
{
ulog (LOG_ERROR, "setreuid (%ld, %ld): %s",
(long) ieuid, (long) iuid, strerror (errno));
return FALSE;
}
#else /* ! HAVE_SETREUID */
#if HAVE_SAVED_SETUID
/* Set the effective user id to the real user id. Since the
effective user id is saved (it's the saved setuid) we will able
to set back to it later. If the real user id is root we will not
be able to switch back and forth, so don't even try. */
if (iuid != 0)
{
if (setuid (iuid) < 0)
{
ulog (LOG_ERROR, "setuid (%ld): %s", (long) iuid, strerror (errno));
return FALSE;
}
}
#else /* ! HAVE_SAVED_SETUID */
/* There's no way to switch between real permissions and effective
permissions. Just try to open the file with the uucp
permissions. */
#endif /* ! HAVE_SAVED_SETUID */
#endif /* ! HAVE_SETREUID */
return TRUE;
}
/* Restore the uucp permissions. */
/*ARGSUSED*/
static boolean
fsuucp_perms (ieuid)
long ieuid;
{
#if HAVE_SETREUID
/* Swap effective and real user id's back to what they were. */
if (! fsuser_perms ((uid_t *) NULL))
return FALSE;
#else /* ! HAVE_SETREUID */
#if HAVE_SAVED_SETUID
/* Set ourselves back to our original effective user id. */
if (setuid ((uid_t) ieuid) < 0)
{
ulog (LOG_ERROR, "setuid (%ld): %s", (long) ieuid, strerror (errno));
/* Is this error message helpful or confusing? */
if (errno == EPERM)
ulog (LOG_ERROR,
"Probably HAVE_SAVED_SETUID in policy.h should be set to 0");
return FALSE;
}
#else /* ! HAVE_SAVED_SETUID */
/* We didn't switch, no need to switch back. */
#endif /* ! HAVE_SAVED_SETUID */
#endif /* ! HAVE_SETREUID */
return TRUE;
}
/* Open a file with the permissions of the invoking user. Ignore the
fbinary argument since Unix has no distinction between text and
binary files. */
/*ARGSUSED*/
openfile_t
esysdep_user_fopen (zfile, frd, fbinary)
const char *zfile;
boolean frd;
boolean fbinary;
{
uid_t ieuid;
openfile_t e;
const char *zerr;
int o = 0;
if (! fsuser_perms (&ieuid))
return EFILECLOSED;
zerr = NULL;
#if USE_STDIO
e = fopen (zfile, frd ? "r" : "w");
if (e == NULL)
zerr = "fopen";
else
o = fileno (e);
#else
if (frd)
{
e = open ((char *) zfile, O_RDONLY | O_NOCTTY, 0);
zerr = "open";
}
else
{
e = creat ((char *) zfile, IPUBLIC_FILE_MODE);
zerr = "creat";
}
if (e >= 0)
{
o = e;
zerr = NULL;
}
#endif
if (! fsuucp_perms ((long) ieuid))
{
if (ffileisopen (e))
(void) ffileclose (e);
return EFILECLOSED;
}
if (zerr != NULL)
{
ulog (LOG_ERROR, "%s (%s): %s", zerr, zfile, strerror (errno));
#if ! HAVE_SETREUID
/* Are these error messages helpful or confusing? */
#if HAVE_SAVED_SETUID
if (errno == EACCES && getuid () == 0)
ulog (LOG_ERROR,
"The superuser may only transfer files that are readable by %s",
OWNER);
#else
if (errno == EACCES)
ulog (LOG_ERROR,
"You may only transfer files that are readable by %s", OWNER);
#endif
#endif /* ! HAVE_SETREUID */
return EFILECLOSED;
}
if (fcntl (o, F_SETFD, fcntl (o, F_GETFD, 0) | FD_CLOEXEC) < 0)
{
ulog (LOG_ERROR, "fcntl (FD_CLOEXEC): %s", strerror (errno));
(void) ffileclose (e);
return EFILECLOSED;
}
return e;
}
|
