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
|
/*
* security/tomoyo/realpath.c
*
* Pathname calculation functions for TOMOYO.
*
* Copyright (C) 2005-2010 NTT DATA CORPORATION
*/
#include <linux/types.h>
#include <linux/mount.h>
#include <linux/mnt_namespace.h>
#include <linux/fs_struct.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include <net/sock.h>
#include "common.h"
#include "../../fs/internal.h"
/**
* tomoyo_encode: Convert binary string to ascii string.
*
* @str: String in binary format.
*
* Returns pointer to @str in ascii format on success, NULL otherwise.
*
* This function uses kzalloc(), so caller must kfree() if this function
* didn't return NULL.
*/
char *tomoyo_encode(const char *str)
{
int len = 0;
const char *p = str;
char *cp;
char *cp0;
if (!p)
return NULL;
while (*p) {
const unsigned char c = *p++;
if (c == '\\')
len += 2;
else if (c > ' ' && c < 127)
len++;
else
len += 4;
}
len++;
/* Reserve space for appending "/". */
cp = kzalloc(len + 10, GFP_NOFS);
if (!cp)
return NULL;
cp0 = cp;
p = str;
while (*p) {
const unsigned char c = *p++;
if (c == '\\') {
*cp++ = '\\';
*cp++ = '\\';
} else if (c > ' ' && c < 127) {
*cp++ = c;
} else {
*cp++ = '\\';
*cp++ = (c >> 6) + '0';
*cp++ = ((c >> 3) & 7) + '0';
*cp++ = (c & 7) + '0';
}
}
return cp0;
}
/**
* tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
*
* @path: Pointer to "struct path".
*
* Returns the realpath of the given @path on success, NULL otherwise.
*
* If dentry is a directory, trailing '/' is appended.
* Characters out of 0x20 < c < 0x7F range are converted to
* \ooo style octal string.
* Character \ is converted to \\ string.
*
* These functions use kzalloc(), so the caller must call kfree()
* if these functions didn't return NULL.
*/
char *tomoyo_realpath_from_path(struct path *path)
{
char *buf = NULL;
char *name = NULL;
unsigned int buf_len = PAGE_SIZE / 2;
struct dentry *dentry = path->dentry;
bool is_dir;
if (!dentry)
return NULL;
is_dir = dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode);
while (1) {
char *pos;
buf_len <<= 1;
kfree(buf);
buf = kmalloc(buf_len, GFP_NOFS);
if (!buf)
break;
/* Get better name for socket. */
if (dentry->d_sb && dentry->d_sb->s_magic == SOCKFS_MAGIC) {
struct inode *inode = dentry->d_inode;
struct socket *sock = inode ? SOCKET_I(inode) : NULL;
struct sock *sk = sock ? sock->sk : NULL;
if (sk) {
snprintf(buf, buf_len - 1, "socket:[family=%u:"
"type=%u:protocol=%u]", sk->sk_family,
sk->sk_type, sk->sk_protocol);
} else {
snprintf(buf, buf_len - 1, "socket:[unknown]");
}
name = tomoyo_encode(buf);
break;
}
/* For "socket:[\$]" and "pipe:[\$]". */
if (dentry->d_op && dentry->d_op->d_dname) {
pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1);
if (IS_ERR(pos))
continue;
name = tomoyo_encode(pos);
break;
}
/* If we don't have a vfsmount, we can't calculate. */
if (!path->mnt)
break;
pos = d_absolute_path(path, buf, buf_len - 1);
/* If path is disconnected, use "[unknown]" instead. */
if (pos == ERR_PTR(-EINVAL)) {
name = tomoyo_encode("[unknown]");
break;
}
/* Prepend "/proc" prefix if using internal proc vfs mount. */
if (!IS_ERR(pos) && (path->mnt->mnt_flags & MNT_INTERNAL) &&
(path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC)) {
pos -= 5;
if (pos >= buf)
memcpy(pos, "/proc", 5);
else
pos = ERR_PTR(-ENOMEM);
}
if (IS_ERR(pos))
continue;
name = tomoyo_encode(pos);
break;
}
kfree(buf);
if (!name)
tomoyo_warn_oom(__func__);
else if (is_dir && *name) {
/* Append trailing '/' if dentry is a directory. */
char *pos = name + strlen(name) - 1;
if (*pos != '/')
/*
* This is OK because tomoyo_encode() reserves space
* for appending "/".
*/
*++pos = '/';
}
return name;
}
/**
* tomoyo_realpath_nofollow - Get realpath of a pathname.
*
* @pathname: The pathname to solve.
*
* Returns the realpath of @pathname on success, NULL otherwise.
*/
char *tomoyo_realpath_nofollow(const char *pathname)
{
struct path path;
if (pathname && kern_path(pathname, 0, &path) == 0) {
char *buf = tomoyo_realpath_from_path(&path);
path_put(&path);
return buf;
}
return NULL;
}
|
