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1/*
2 * security/tomoyo/realpath.c
3 *
4 * Copyright (C) 2005-2011 NTT DATA CORPORATION
5 */
6
7#include "common.h"
8#include <linux/magic.h>
9
10/**
11 * tomoyo_encode2 - Encode binary string to ascii string.
12 *
13 * @str: String in binary format.
14 * @str_len: Size of @str in byte.
15 *
16 * Returns pointer to @str in ascii format on success, NULL otherwise.
17 *
18 * This function uses kzalloc(), so caller must kfree() if this function
19 * didn't return NULL.
20 */
21char *tomoyo_encode2(const char *str, int str_len)
22{
23 int i;
24 int len = 0;
25 const char *p = str;
26 char *cp;
27 char *cp0;
28
29 if (!p)
30 return NULL;
31 for (i = 0; i < str_len; i++) {
32 const unsigned char c = p[i];
33
34 if (c == '\\')
35 len += 2;
36 else if (c > ' ' && c < 127)
37 len++;
38 else
39 len += 4;
40 }
41 len++;
42 /* Reserve space for appending "/". */
43 cp = kzalloc(len + 10, GFP_NOFS);
44 if (!cp)
45 return NULL;
46 cp0 = cp;
47 p = str;
48 for (i = 0; i < str_len; i++) {
49 const unsigned char c = p[i];
50
51 if (c == '\\') {
52 *cp++ = '\\';
53 *cp++ = '\\';
54 } else if (c > ' ' && c < 127) {
55 *cp++ = c;
56 } else {
57 *cp++ = '\\';
58 *cp++ = (c >> 6) + '0';
59 *cp++ = ((c >> 3) & 7) + '0';
60 *cp++ = (c & 7) + '0';
61 }
62 }
63 return cp0;
64}
65
66/**
67 * tomoyo_encode - Encode binary string to ascii string.
68 *
69 * @str: String in binary format.
70 *
71 * Returns pointer to @str in ascii format on success, NULL otherwise.
72 *
73 * This function uses kzalloc(), so caller must kfree() if this function
74 * didn't return NULL.
75 */
76char *tomoyo_encode(const char *str)
77{
78 return str ? tomoyo_encode2(str, strlen(str)) : NULL;
79}
80
81/**
82 * tomoyo_get_absolute_path - Get the path of a dentry but ignores chroot'ed root.
83 *
84 * @path: Pointer to "struct path".
85 * @buffer: Pointer to buffer to return value in.
86 * @buflen: Sizeof @buffer.
87 *
88 * Returns the buffer on success, an error code otherwise.
89 *
90 * If dentry is a directory, trailing '/' is appended.
91 */
92static char *tomoyo_get_absolute_path(struct path *path, char * const buffer,
93 const int buflen)
94{
95 char *pos = ERR_PTR(-ENOMEM);
96 if (buflen >= 256) {
97 /* go to whatever namespace root we are under */
98 pos = d_absolute_path(path, buffer, buflen - 1);
99 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
100 struct inode *inode = path->dentry->d_inode;
101 if (inode && S_ISDIR(inode->i_mode)) {
102 buffer[buflen - 2] = '/';
103 buffer[buflen - 1] = '\0';
104 }
105 }
106 }
107 return pos;
108}
109
110/**
111 * tomoyo_get_dentry_path - Get the path of a dentry.
112 *
113 * @dentry: Pointer to "struct dentry".
114 * @buffer: Pointer to buffer to return value in.
115 * @buflen: Sizeof @buffer.
116 *
117 * Returns the buffer on success, an error code otherwise.
118 *
119 * If dentry is a directory, trailing '/' is appended.
120 */
121static char *tomoyo_get_dentry_path(struct dentry *dentry, char * const buffer,
122 const int buflen)
123{
124 char *pos = ERR_PTR(-ENOMEM);
125 if (buflen >= 256) {
126 pos = dentry_path_raw(dentry, buffer, buflen - 1);
127 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
128 struct inode *inode = dentry->d_inode;
129 if (inode && S_ISDIR(inode->i_mode)) {
130 buffer[buflen - 2] = '/';
131 buffer[buflen - 1] = '\0';
132 }
133 }
134 }
135 return pos;
136}
137
138/**
139 * tomoyo_get_local_path - Get the path of a dentry.
140 *
141 * @dentry: Pointer to "struct dentry".
142 * @buffer: Pointer to buffer to return value in.
143 * @buflen: Sizeof @buffer.
144 *
145 * Returns the buffer on success, an error code otherwise.
146 */
147static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer,
148 const int buflen)
149{
150 struct super_block *sb = dentry->d_sb;
151 char *pos = tomoyo_get_dentry_path(dentry, buffer, buflen);
152 if (IS_ERR(pos))
153 return pos;
154 /* Convert from $PID to self if $PID is current thread. */
155 if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') {
156 char *ep;
157 const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10);
158 if (*ep == '/' && pid && pid ==
159 task_tgid_nr_ns(current, sb->s_fs_info)) {
160 pos = ep - 5;
161 if (pos < buffer)
162 goto out;
163 memmove(pos, "/self", 5);
164 }
165 goto prepend_filesystem_name;
166 }
167 /* Use filesystem name for unnamed devices. */
168 if (!MAJOR(sb->s_dev))
169 goto prepend_filesystem_name;
170 {
171 struct inode *inode = sb->s_root->d_inode;
172 /*
173 * Use filesystem name if filesystem does not support rename()
174 * operation.
175 */
176 if (!inode->i_op->rename)
177 goto prepend_filesystem_name;
178 }
179 /* Prepend device name. */
180 {
181 char name[64];
182 int name_len;
183 const dev_t dev = sb->s_dev;
184 name[sizeof(name) - 1] = '\0';
185 snprintf(name, sizeof(name) - 1, "dev(%u,%u):", MAJOR(dev),
186 MINOR(dev));
187 name_len = strlen(name);
188 pos -= name_len;
189 if (pos < buffer)
190 goto out;
191 memmove(pos, name, name_len);
192 return pos;
193 }
194 /* Prepend filesystem name. */
195prepend_filesystem_name:
196 {
197 const char *name = sb->s_type->name;
198 const int name_len = strlen(name);
199 pos -= name_len + 1;
200 if (pos < buffer)
201 goto out;
202 memmove(pos, name, name_len);
203 pos[name_len] = ':';
204 }
205 return pos;
206out:
207 return ERR_PTR(-ENOMEM);
208}
209
210/**
211 * tomoyo_get_socket_name - Get the name of a socket.
212 *
213 * @path: Pointer to "struct path".
214 * @buffer: Pointer to buffer to return value in.
215 * @buflen: Sizeof @buffer.
216 *
217 * Returns the buffer.
218 */
219static char *tomoyo_get_socket_name(struct path *path, char * const buffer,
220 const int buflen)
221{
222 struct inode *inode = path->dentry->d_inode;
223 struct socket *sock = inode ? SOCKET_I(inode) : NULL;
224 struct sock *sk = sock ? sock->sk : NULL;
225 if (sk) {
226 snprintf(buffer, buflen, "socket:[family=%u:type=%u:"
227 "protocol=%u]", sk->sk_family, sk->sk_type,
228 sk->sk_protocol);
229 } else {
230 snprintf(buffer, buflen, "socket:[unknown]");
231 }
232 return buffer;
233}
234
235/**
236 * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
237 *
238 * @path: Pointer to "struct path".
239 *
240 * Returns the realpath of the given @path on success, NULL otherwise.
241 *
242 * If dentry is a directory, trailing '/' is appended.
243 * Characters out of 0x20 < c < 0x7F range are converted to
244 * \ooo style octal string.
245 * Character \ is converted to \\ string.
246 *
247 * These functions use kzalloc(), so the caller must call kfree()
248 * if these functions didn't return NULL.
249 */
250char *tomoyo_realpath_from_path(struct path *path)
251{
252 char *buf = NULL;
253 char *name = NULL;
254 unsigned int buf_len = PAGE_SIZE / 2;
255 struct dentry *dentry = path->dentry;
256 struct super_block *sb;
257 if (!dentry)
258 return NULL;
259 sb = dentry->d_sb;
260 while (1) {
261 char *pos;
262 struct inode *inode;
263 buf_len <<= 1;
264 kfree(buf);
265 buf = kmalloc(buf_len, GFP_NOFS);
266 if (!buf)
267 break;
268 /* To make sure that pos is '\0' terminated. */
269 buf[buf_len - 1] = '\0';
270 /* Get better name for socket. */
271 if (sb->s_magic == SOCKFS_MAGIC) {
272 pos = tomoyo_get_socket_name(path, buf, buf_len - 1);
273 goto encode;
274 }
275 /* For "pipe:[\$]". */
276 if (dentry->d_op && dentry->d_op->d_dname) {
277 pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1);
278 goto encode;
279 }
280 inode = sb->s_root->d_inode;
281 /*
282 * Get local name for filesystems without rename() operation
283 * or dentry without vfsmount.
284 */
285 if (!path->mnt || !inode->i_op->rename)
286 pos = tomoyo_get_local_path(path->dentry, buf,
287 buf_len - 1);
288 /* Get absolute name for the rest. */
289 else {
290 pos = tomoyo_get_absolute_path(path, buf, buf_len - 1);
291 /*
292 * Fall back to local name if absolute name is not
293 * available.
294 */
295 if (pos == ERR_PTR(-EINVAL))
296 pos = tomoyo_get_local_path(path->dentry, buf,
297 buf_len - 1);
298 }
299encode:
300 if (IS_ERR(pos))
301 continue;
302 name = tomoyo_encode(pos);
303 break;
304 }
305 kfree(buf);
306 if (!name)
307 tomoyo_warn_oom(__func__);
308 return name;
309}
310
311/**
312 * tomoyo_realpath_nofollow - Get realpath of a pathname.
313 *
314 * @pathname: The pathname to solve.
315 *
316 * Returns the realpath of @pathname on success, NULL otherwise.
317 */
318char *tomoyo_realpath_nofollow(const char *pathname)
319{
320 struct path path;
321
322 if (pathname && kern_path(pathname, 0, &path) == 0) {
323 char *buf = tomoyo_realpath_from_path(&path);
324 path_put(&path);
325 return buf;
326 }
327 return NULL;
328}
1/*
2 * security/tomoyo/realpath.c
3 *
4 * Copyright (C) 2005-2011 NTT DATA CORPORATION
5 */
6
7#include <linux/types.h>
8#include <linux/mount.h>
9#include <linux/mnt_namespace.h>
10#include <linux/fs_struct.h>
11#include <linux/magic.h>
12#include <linux/slab.h>
13#include <net/sock.h>
14#include "common.h"
15#include "../../fs/internal.h"
16
17/**
18 * tomoyo_encode: Convert binary string to ascii string.
19 *
20 * @str: String in binary format.
21 *
22 * Returns pointer to @str in ascii format on success, NULL otherwise.
23 *
24 * This function uses kzalloc(), so caller must kfree() if this function
25 * didn't return NULL.
26 */
27char *tomoyo_encode(const char *str)
28{
29 int len = 0;
30 const char *p = str;
31 char *cp;
32 char *cp0;
33
34 if (!p)
35 return NULL;
36 while (*p) {
37 const unsigned char c = *p++;
38 if (c == '\\')
39 len += 2;
40 else if (c > ' ' && c < 127)
41 len++;
42 else
43 len += 4;
44 }
45 len++;
46 /* Reserve space for appending "/". */
47 cp = kzalloc(len + 10, GFP_NOFS);
48 if (!cp)
49 return NULL;
50 cp0 = cp;
51 p = str;
52 while (*p) {
53 const unsigned char c = *p++;
54
55 if (c == '\\') {
56 *cp++ = '\\';
57 *cp++ = '\\';
58 } else if (c > ' ' && c < 127) {
59 *cp++ = c;
60 } else {
61 *cp++ = '\\';
62 *cp++ = (c >> 6) + '0';
63 *cp++ = ((c >> 3) & 7) + '0';
64 *cp++ = (c & 7) + '0';
65 }
66 }
67 return cp0;
68}
69
70/**
71 * tomoyo_get_absolute_path - Get the path of a dentry but ignores chroot'ed root.
72 *
73 * @path: Pointer to "struct path".
74 * @buffer: Pointer to buffer to return value in.
75 * @buflen: Sizeof @buffer.
76 *
77 * Returns the buffer on success, an error code otherwise.
78 *
79 * If dentry is a directory, trailing '/' is appended.
80 */
81static char *tomoyo_get_absolute_path(struct path *path, char * const buffer,
82 const int buflen)
83{
84 char *pos = ERR_PTR(-ENOMEM);
85 if (buflen >= 256) {
86 struct path ns_root = { };
87 /* go to whatever namespace root we are under */
88 pos = __d_path(path, &ns_root, buffer, buflen - 1);
89 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
90 struct inode *inode = path->dentry->d_inode;
91 if (inode && S_ISDIR(inode->i_mode)) {
92 buffer[buflen - 2] = '/';
93 buffer[buflen - 1] = '\0';
94 }
95 }
96 }
97 return pos;
98}
99
100/**
101 * tomoyo_get_dentry_path - Get the path of a dentry.
102 *
103 * @dentry: Pointer to "struct dentry".
104 * @buffer: Pointer to buffer to return value in.
105 * @buflen: Sizeof @buffer.
106 *
107 * Returns the buffer on success, an error code otherwise.
108 *
109 * If dentry is a directory, trailing '/' is appended.
110 */
111static char *tomoyo_get_dentry_path(struct dentry *dentry, char * const buffer,
112 const int buflen)
113{
114 char *pos = ERR_PTR(-ENOMEM);
115 if (buflen >= 256) {
116 pos = dentry_path_raw(dentry, buffer, buflen - 1);
117 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
118 struct inode *inode = dentry->d_inode;
119 if (inode && S_ISDIR(inode->i_mode)) {
120 buffer[buflen - 2] = '/';
121 buffer[buflen - 1] = '\0';
122 }
123 }
124 }
125 return pos;
126}
127
128/**
129 * tomoyo_get_local_path - Get the path of a dentry.
130 *
131 * @dentry: Pointer to "struct dentry".
132 * @buffer: Pointer to buffer to return value in.
133 * @buflen: Sizeof @buffer.
134 *
135 * Returns the buffer on success, an error code otherwise.
136 */
137static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer,
138 const int buflen)
139{
140 struct super_block *sb = dentry->d_sb;
141 char *pos = tomoyo_get_dentry_path(dentry, buffer, buflen);
142 if (IS_ERR(pos))
143 return pos;
144 /* Convert from $PID to self if $PID is current thread. */
145 if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') {
146 char *ep;
147 const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10);
148 if (*ep == '/' && pid && pid ==
149 task_tgid_nr_ns(current, sb->s_fs_info)) {
150 pos = ep - 5;
151 if (pos < buffer)
152 goto out;
153 memmove(pos, "/self", 5);
154 }
155 goto prepend_filesystem_name;
156 }
157 /* Use filesystem name for unnamed devices. */
158 if (!MAJOR(sb->s_dev))
159 goto prepend_filesystem_name;
160 {
161 struct inode *inode = sb->s_root->d_inode;
162 /*
163 * Use filesystem name if filesystem does not support rename()
164 * operation.
165 */
166 if (inode->i_op && !inode->i_op->rename)
167 goto prepend_filesystem_name;
168 }
169 /* Prepend device name. */
170 {
171 char name[64];
172 int name_len;
173 const dev_t dev = sb->s_dev;
174 name[sizeof(name) - 1] = '\0';
175 snprintf(name, sizeof(name) - 1, "dev(%u,%u):", MAJOR(dev),
176 MINOR(dev));
177 name_len = strlen(name);
178 pos -= name_len;
179 if (pos < buffer)
180 goto out;
181 memmove(pos, name, name_len);
182 return pos;
183 }
184 /* Prepend filesystem name. */
185prepend_filesystem_name:
186 {
187 const char *name = sb->s_type->name;
188 const int name_len = strlen(name);
189 pos -= name_len + 1;
190 if (pos < buffer)
191 goto out;
192 memmove(pos, name, name_len);
193 pos[name_len] = ':';
194 }
195 return pos;
196out:
197 return ERR_PTR(-ENOMEM);
198}
199
200/**
201 * tomoyo_get_socket_name - Get the name of a socket.
202 *
203 * @path: Pointer to "struct path".
204 * @buffer: Pointer to buffer to return value in.
205 * @buflen: Sizeof @buffer.
206 *
207 * Returns the buffer.
208 */
209static char *tomoyo_get_socket_name(struct path *path, char * const buffer,
210 const int buflen)
211{
212 struct inode *inode = path->dentry->d_inode;
213 struct socket *sock = inode ? SOCKET_I(inode) : NULL;
214 struct sock *sk = sock ? sock->sk : NULL;
215 if (sk) {
216 snprintf(buffer, buflen, "socket:[family=%u:type=%u:"
217 "protocol=%u]", sk->sk_family, sk->sk_type,
218 sk->sk_protocol);
219 } else {
220 snprintf(buffer, buflen, "socket:[unknown]");
221 }
222 return buffer;
223}
224
225/**
226 * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
227 *
228 * @path: Pointer to "struct path".
229 *
230 * Returns the realpath of the given @path on success, NULL otherwise.
231 *
232 * If dentry is a directory, trailing '/' is appended.
233 * Characters out of 0x20 < c < 0x7F range are converted to
234 * \ooo style octal string.
235 * Character \ is converted to \\ string.
236 *
237 * These functions use kzalloc(), so the caller must call kfree()
238 * if these functions didn't return NULL.
239 */
240char *tomoyo_realpath_from_path(struct path *path)
241{
242 char *buf = NULL;
243 char *name = NULL;
244 unsigned int buf_len = PAGE_SIZE / 2;
245 struct dentry *dentry = path->dentry;
246 struct super_block *sb;
247 if (!dentry)
248 return NULL;
249 sb = dentry->d_sb;
250 while (1) {
251 char *pos;
252 struct inode *inode;
253 buf_len <<= 1;
254 kfree(buf);
255 buf = kmalloc(buf_len, GFP_NOFS);
256 if (!buf)
257 break;
258 /* To make sure that pos is '\0' terminated. */
259 buf[buf_len - 1] = '\0';
260 /* Get better name for socket. */
261 if (sb->s_magic == SOCKFS_MAGIC) {
262 pos = tomoyo_get_socket_name(path, buf, buf_len - 1);
263 goto encode;
264 }
265 /* For "pipe:[\$]". */
266 if (dentry->d_op && dentry->d_op->d_dname) {
267 pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1);
268 goto encode;
269 }
270 inode = sb->s_root->d_inode;
271 /*
272 * Get local name for filesystems without rename() operation
273 * or dentry without vfsmount.
274 */
275 if (!path->mnt || (inode->i_op && !inode->i_op->rename))
276 pos = tomoyo_get_local_path(path->dentry, buf,
277 buf_len - 1);
278 /* Get absolute name for the rest. */
279 else
280 pos = tomoyo_get_absolute_path(path, buf, buf_len - 1);
281encode:
282 if (IS_ERR(pos))
283 continue;
284 name = tomoyo_encode(pos);
285 break;
286 }
287 kfree(buf);
288 if (!name)
289 tomoyo_warn_oom(__func__);
290 return name;
291}
292
293/**
294 * tomoyo_realpath_nofollow - Get realpath of a pathname.
295 *
296 * @pathname: The pathname to solve.
297 *
298 * Returns the realpath of @pathname on success, NULL otherwise.
299 */
300char *tomoyo_realpath_nofollow(const char *pathname)
301{
302 struct path path;
303
304 if (pathname && kern_path(pathname, 0, &path) == 0) {
305 char *buf = tomoyo_realpath_from_path(&path);
306 path_put(&path);
307 return buf;
308 }
309 return NULL;
310}