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
|
/*
* smbumount.c
*
* Copyright (C) 1995-1998 by Volker Lendecke
*
*/
#define SMBMOUNT_MALLOC 1
#include "includes.h"
#include <mntent.h>
#include <asm/types.h>
#include <asm/posix_types.h>
#include <linux/smb.h>
#include <linux/smb_mount.h>
#include <linux/smb_fs.h>
/* This is a (hopefully) temporary hack due to the fact that
sizeof( uid_t ) != sizeof( __kernel_uid_t ) under glibc.
This may change in the future and smb.h may get fixed in the
future. In the mean time, it's ugly hack time - get over it.
*/
#undef SMB_IOC_GETMOUNTUID
#define SMB_IOC_GETMOUNTUID _IOR('u', 1, __kernel_uid_t)
#ifndef O_NOFOLLOW
#define O_NOFOLLOW 0400000
#endif
static void
usage(void)
{
printf("usage: smbumount mountpoint\n");
}
static int
umount_ok(const char *mount_point)
{
/* we set O_NOFOLLOW to prevent users playing games with symlinks to
umount filesystems they don't own */
int fid = open(mount_point, O_RDONLY|O_NOFOLLOW, 0);
__kernel_uid32_t mount_uid;
if (fid == -1) {
fprintf(stderr, "Could not open %s: %s\n",
mount_point, strerror(errno));
return -1;
}
if (ioctl(fid, SMB_IOC_GETMOUNTUID32, &mount_uid) != 0) {
__kernel_uid_t mount_uid16;
if (ioctl(fid, SMB_IOC_GETMOUNTUID, &mount_uid16) != 0) {
fprintf(stderr, "%s probably not smb-filesystem\n",
mount_point);
return -1;
}
mount_uid = mount_uid16;
}
if ((getuid() != 0)
&& (mount_uid != getuid())) {
fprintf(stderr, "You are not allowed to umount %s\n",
mount_point);
return -1;
}
close(fid);
return 0;
}
/* Make a canonical pathname from PATH. Returns a freshly malloced string.
It is up the *caller* to ensure that the PATH is sensible. i.e.
canonicalize ("/dev/fd0/.") returns "/dev/fd0" even though ``/dev/fd0/.''
is not a legal pathname for ``/dev/fd0'' Anything we cannot parse
we return unmodified. */
static char *
canonicalize (char *path)
{
char *canonical = malloc (PATH_MAX + 1);
if (!canonical) {
fprintf(stderr, "Error! Not enough memory!\n");
return NULL;
}
if (strlen(path) > PATH_MAX) {
fprintf(stderr, "Mount point string too long\n");
return NULL;
}
if (path == NULL)
return NULL;
if (realpath (path, canonical))
return canonical;
strncpy (canonical, path, PATH_MAX);
canonical[PATH_MAX] = '\0';
return canonical;
}
int
main(int argc, char *argv[])
{
int fd;
char* mount_point;
struct mntent *mnt;
FILE* mtab;
FILE* new_mtab;
if (argc != 2) {
usage();
exit(1);
}
if (geteuid() != 0) {
fprintf(stderr, "smbumount must be installed suid root\n");
exit(1);
}
mount_point = canonicalize(argv[1]);
if (mount_point == NULL)
{
exit(1);
}
if (umount_ok(mount_point) != 0) {
exit(1);
}
if (umount(mount_point) != 0) {
fprintf(stderr, "Could not umount %s: %s\n",
mount_point, strerror(errno));
exit(1);
}
if ((fd = open(MOUNTED"~", O_RDWR|O_CREAT|O_EXCL, 0600)) == -1)
{
fprintf(stderr, "Can't get "MOUNTED"~ lock file");
return 1;
}
close(fd);
if ((mtab = setmntent(MOUNTED, "r")) == NULL) {
fprintf(stderr, "Can't open " MOUNTED ": %s\n",
strerror(errno));
return 1;
}
#define MOUNTED_TMP MOUNTED".tmp"
if ((new_mtab = setmntent(MOUNTED_TMP, "w")) == NULL) {
fprintf(stderr, "Can't open " MOUNTED_TMP ": %s\n",
strerror(errno));
endmntent(mtab);
return 1;
}
while ((mnt = getmntent(mtab)) != NULL) {
if (strcmp(mnt->mnt_dir, mount_point) != 0) {
addmntent(new_mtab, mnt);
}
}
endmntent(mtab);
if (fchmod (fileno (new_mtab), S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH) < 0) {
fprintf(stderr, "Error changing mode of %s: %s\n",
MOUNTED_TMP, strerror(errno));
exit(1);
}
endmntent(new_mtab);
if (rename(MOUNTED_TMP, MOUNTED) < 0) {
fprintf(stderr, "Cannot rename %s to %s: %s\n",
MOUNTED, MOUNTED_TMP, strerror(errno));
exit(1);
}
if (unlink(MOUNTED"~") == -1)
{
fprintf(stderr, "Can't remove "MOUNTED"~");
return 1;
}
return 0;
}
|
