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