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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * security/tomoyo/realpath.c
4 *
5 * Copyright (C) 2005-2011 NTT DATA CORPORATION
6 */
7
8#include "common.h"
9#include <linux/magic.h>
10
11/**
12 * tomoyo_encode2 - Encode binary string to ascii string.
13 *
14 * @str: String in binary format.
15 * @str_len: Size of @str in byte.
16 *
17 * Returns pointer to @str in ascii format on success, NULL otherwise.
18 *
19 * This function uses kzalloc(), so caller must kfree() if this function
20 * didn't return NULL.
21 */
22char *tomoyo_encode2(const char *str, int str_len)
23{
24 int i;
25 int len = 0;
26 const char *p = str;
27 char *cp;
28 char *cp0;
29
30 if (!p)
31 return NULL;
32 for (i = 0; i < str_len; i++) {
33 const unsigned char c = p[i];
34
35 if (c == '\\')
36 len += 2;
37 else if (c > ' ' && c < 127)
38 len++;
39 else
40 len += 4;
41 }
42 len++;
43 /* Reserve space for appending "/". */
44 cp = kzalloc(len + 10, GFP_NOFS);
45 if (!cp)
46 return NULL;
47 cp0 = cp;
48 p = str;
49 for (i = 0; i < str_len; i++) {
50 const unsigned char c = p[i];
51
52 if (c == '\\') {
53 *cp++ = '\\';
54 *cp++ = '\\';
55 } else if (c > ' ' && c < 127) {
56 *cp++ = c;
57 } else {
58 *cp++ = '\\';
59 *cp++ = (c >> 6) + '0';
60 *cp++ = ((c >> 3) & 7) + '0';
61 *cp++ = (c & 7) + '0';
62 }
63 }
64 return cp0;
65}
66
67/**
68 * tomoyo_encode - Encode binary string to ascii string.
69 *
70 * @str: String in binary format.
71 *
72 * Returns pointer to @str in ascii format on success, NULL otherwise.
73 *
74 * This function uses kzalloc(), so caller must kfree() if this function
75 * didn't return NULL.
76 */
77char *tomoyo_encode(const char *str)
78{
79 return str ? tomoyo_encode2(str, strlen(str)) : NULL;
80}
81
82/**
83 * tomoyo_get_absolute_path - Get the path of a dentry but ignores chroot'ed root.
84 *
85 * @path: Pointer to "struct path".
86 * @buffer: Pointer to buffer to return value in.
87 * @buflen: Sizeof @buffer.
88 *
89 * Returns the buffer on success, an error code otherwise.
90 *
91 * If dentry is a directory, trailing '/' is appended.
92 */
93static char *tomoyo_get_absolute_path(const struct path *path, char * const buffer,
94 const int buflen)
95{
96 char *pos = ERR_PTR(-ENOMEM);
97
98 if (buflen >= 256) {
99 /* go to whatever namespace root we are under */
100 pos = d_absolute_path(path, buffer, buflen - 1);
101 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
102 struct inode *inode = d_backing_inode(path->dentry);
103
104 if (inode && S_ISDIR(inode->i_mode)) {
105 buffer[buflen - 2] = '/';
106 buffer[buflen - 1] = '\0';
107 }
108 }
109 }
110 return pos;
111}
112
113/**
114 * tomoyo_get_dentry_path - Get the path of a dentry.
115 *
116 * @dentry: Pointer to "struct dentry".
117 * @buffer: Pointer to buffer to return value in.
118 * @buflen: Sizeof @buffer.
119 *
120 * Returns the buffer on success, an error code otherwise.
121 *
122 * If dentry is a directory, trailing '/' is appended.
123 */
124static char *tomoyo_get_dentry_path(struct dentry *dentry, char * const buffer,
125 const int buflen)
126{
127 char *pos = ERR_PTR(-ENOMEM);
128
129 if (buflen >= 256) {
130 pos = dentry_path_raw(dentry, buffer, buflen - 1);
131 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
132 struct inode *inode = d_backing_inode(dentry);
133
134 if (inode && S_ISDIR(inode->i_mode)) {
135 buffer[buflen - 2] = '/';
136 buffer[buflen - 1] = '\0';
137 }
138 }
139 }
140 return pos;
141}
142
143/**
144 * tomoyo_get_local_path - Get the path of a dentry.
145 *
146 * @dentry: Pointer to "struct dentry".
147 * @buffer: Pointer to buffer to return value in.
148 * @buflen: Sizeof @buffer.
149 *
150 * Returns the buffer on success, an error code otherwise.
151 */
152static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer,
153 const int buflen)
154{
155 struct super_block *sb = dentry->d_sb;
156 char *pos = tomoyo_get_dentry_path(dentry, buffer, buflen);
157
158 if (IS_ERR(pos))
159 return pos;
160 /* Convert from $PID to self if $PID is current thread. */
161 if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') {
162 char *ep;
163 const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10);
164
165 if (*ep == '/' && pid && pid ==
166 task_tgid_nr_ns(current, sb->s_fs_info)) {
167 pos = ep - 5;
168 if (pos < buffer)
169 goto out;
170 memmove(pos, "/self", 5);
171 }
172 goto prepend_filesystem_name;
173 }
174 /* Use filesystem name for unnamed devices. */
175 if (!MAJOR(sb->s_dev))
176 goto prepend_filesystem_name;
177 {
178 struct inode *inode = d_backing_inode(sb->s_root);
179
180 /*
181 * Use filesystem name if filesystem does not support rename()
182 * operation.
183 */
184 if (!inode->i_op->rename)
185 goto prepend_filesystem_name;
186 }
187 /* Prepend device name. */
188 {
189 char name[64];
190 int name_len;
191 const dev_t dev = sb->s_dev;
192
193 name[sizeof(name) - 1] = '\0';
194 snprintf(name, sizeof(name) - 1, "dev(%u,%u):", MAJOR(dev),
195 MINOR(dev));
196 name_len = strlen(name);
197 pos -= name_len;
198 if (pos < buffer)
199 goto out;
200 memmove(pos, name, name_len);
201 return pos;
202 }
203 /* Prepend filesystem name. */
204prepend_filesystem_name:
205 {
206 const char *name = sb->s_type->name;
207 const int name_len = strlen(name);
208
209 pos -= name_len + 1;
210 if (pos < buffer)
211 goto out;
212 memmove(pos, name, name_len);
213 pos[name_len] = ':';
214 }
215 return pos;
216out:
217 return ERR_PTR(-ENOMEM);
218}
219
220/**
221 * tomoyo_get_socket_name - Get the name of a socket.
222 *
223 * @path: Pointer to "struct path".
224 * @buffer: Pointer to buffer to return value in.
225 * @buflen: Sizeof @buffer.
226 *
227 * Returns the buffer.
228 */
229static char *tomoyo_get_socket_name(const struct path *path, char * const buffer,
230 const int buflen)
231{
232 struct inode *inode = d_backing_inode(path->dentry);
233 struct socket *sock = inode ? SOCKET_I(inode) : NULL;
234 struct sock *sk = sock ? sock->sk : NULL;
235
236 if (sk) {
237 snprintf(buffer, buflen, "socket:[family=%u:type=%u:protocol=%u]",
238 sk->sk_family, sk->sk_type, sk->sk_protocol);
239 } else {
240 snprintf(buffer, buflen, "socket:[unknown]");
241 }
242 return buffer;
243}
244
245/**
246 * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
247 *
248 * @path: Pointer to "struct path".
249 *
250 * Returns the realpath of the given @path on success, NULL otherwise.
251 *
252 * If dentry is a directory, trailing '/' is appended.
253 * Characters out of 0x20 < c < 0x7F range are converted to
254 * \ooo style octal string.
255 * Character \ is converted to \\ string.
256 *
257 * These functions use kzalloc(), so the caller must call kfree()
258 * if these functions didn't return NULL.
259 */
260char *tomoyo_realpath_from_path(const struct path *path)
261{
262 char *buf = NULL;
263 char *name = NULL;
264 unsigned int buf_len = PAGE_SIZE / 2;
265 struct dentry *dentry = path->dentry;
266 struct super_block *sb;
267
268 if (!dentry)
269 return NULL;
270 sb = dentry->d_sb;
271 while (1) {
272 char *pos;
273 struct inode *inode;
274
275 buf_len <<= 1;
276 kfree(buf);
277 buf = kmalloc(buf_len, GFP_NOFS);
278 if (!buf)
279 break;
280 /* To make sure that pos is '\0' terminated. */
281 buf[buf_len - 1] = '\0';
282 /* Get better name for socket. */
283 if (sb->s_magic == SOCKFS_MAGIC) {
284 pos = tomoyo_get_socket_name(path, buf, buf_len - 1);
285 goto encode;
286 }
287 /* For "pipe:[\$]". */
288 if (dentry->d_op && dentry->d_op->d_dname) {
289 pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1);
290 goto encode;
291 }
292 inode = d_backing_inode(sb->s_root);
293 /*
294 * Get local name for filesystems without rename() operation
295 * or dentry without vfsmount.
296 */
297 if (!path->mnt ||
298 (!inode->i_op->rename &&
299 !(sb->s_type->fs_flags & FS_REQUIRES_DEV)))
300 pos = tomoyo_get_local_path(path->dentry, buf,
301 buf_len - 1);
302 /* Get absolute name for the rest. */
303 else {
304 pos = tomoyo_get_absolute_path(path, buf, buf_len - 1);
305 /*
306 * Fall back to local name if absolute name is not
307 * available.
308 */
309 if (pos == ERR_PTR(-EINVAL))
310 pos = tomoyo_get_local_path(path->dentry, buf,
311 buf_len - 1);
312 }
313encode:
314 if (IS_ERR(pos))
315 continue;
316 name = tomoyo_encode(pos);
317 break;
318 }
319 kfree(buf);
320 if (!name)
321 tomoyo_warn_oom(__func__);
322 return name;
323}
324
325/**
326 * tomoyo_realpath_nofollow - Get realpath of a pathname.
327 *
328 * @pathname: The pathname to solve.
329 *
330 * Returns the realpath of @pathname on success, NULL otherwise.
331 */
332char *tomoyo_realpath_nofollow(const char *pathname)
333{
334 struct path path;
335
336 if (pathname && kern_path(pathname, 0, &path) == 0) {
337 char *buf = tomoyo_realpath_from_path(&path);
338
339 path_put(&path);
340 return buf;
341 }
342 return NULL;
343}
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}