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 97
99 if (buflen >= 256) { 98 if (buflen >= 256) {
100 /* go to whatever namespace ro 99 /* go to whatever namespace root we are under */
101 pos = d_absolute_path(path, bu 100 pos = d_absolute_path(path, buffer, buflen - 1);
102 if (!IS_ERR(pos) && *pos == '/ 101 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
103 struct inode *inode = 102 struct inode *inode = d_backing_inode(path->dentry);
104 103
105 if (inode && S_ISDIR(i 104 if (inode && S_ISDIR(inode->i_mode)) {
106 buffer[buflen 105 buffer[buflen - 2] = '/';
107 buffer[buflen 106 buffer[buflen - 1] = '\0';
108 } 107 }
109 } 108 }
110 } 109 }
111 return pos; 110 return pos;
112 } 111 }
113 112
114 /** 113 /**
115 * tomoyo_get_dentry_path - Get the path of a 114 * tomoyo_get_dentry_path - Get the path of a dentry.
116 * 115 *
117 * @dentry: Pointer to "struct dentry". 116 * @dentry: Pointer to "struct dentry".
118 * @buffer: Pointer to buffer to return value 117 * @buffer: Pointer to buffer to return value in.
119 * @buflen: Sizeof @buffer. 118 * @buflen: Sizeof @buffer.
120 * 119 *
121 * Returns the buffer on success, an error cod 120 * Returns the buffer on success, an error code otherwise.
122 * 121 *
123 * If dentry is a directory, trailing '/' is a 122 * If dentry is a directory, trailing '/' is appended.
124 */ 123 */
125 static char *tomoyo_get_dentry_path(struct den 124 static char *tomoyo_get_dentry_path(struct dentry *dentry, char * const buffer,
126 const int 125 const int buflen)
127 { 126 {
128 char *pos = ERR_PTR(-ENOMEM); 127 char *pos = ERR_PTR(-ENOMEM);
129 128
130 if (buflen >= 256) { 129 if (buflen >= 256) {
131 pos = dentry_path_raw(dentry, 130 pos = dentry_path_raw(dentry, buffer, buflen - 1);
132 if (!IS_ERR(pos) && *pos == '/ 131 if (!IS_ERR(pos) && *pos == '/' && pos[1]) {
133 struct inode *inode = 132 struct inode *inode = d_backing_inode(dentry);
134 133
135 if (inode && S_ISDIR(i 134 if (inode && S_ISDIR(inode->i_mode)) {
136 buffer[buflen 135 buffer[buflen - 2] = '/';
137 buffer[buflen 136 buffer[buflen - 1] = '\0';
138 } 137 }
139 } 138 }
140 } 139 }
141 return pos; 140 return pos;
142 } 141 }
143 142
144 /** 143 /**
145 * tomoyo_get_local_path - Get the path of a d 144 * tomoyo_get_local_path - Get the path of a dentry.
146 * 145 *
147 * @dentry: Pointer to "struct dentry". 146 * @dentry: Pointer to "struct dentry".
148 * @buffer: Pointer to buffer to return value 147 * @buffer: Pointer to buffer to return value in.
149 * @buflen: Sizeof @buffer. 148 * @buflen: Sizeof @buffer.
150 * 149 *
151 * Returns the buffer on success, an error cod 150 * Returns the buffer on success, an error code otherwise.
152 */ 151 */
153 static char *tomoyo_get_local_path(struct dent 152 static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer,
154 const int b 153 const int buflen)
155 { 154 {
156 struct super_block *sb = dentry->d_sb; 155 struct super_block *sb = dentry->d_sb;
157 char *pos = tomoyo_get_dentry_path(den 156 char *pos = tomoyo_get_dentry_path(dentry, buffer, buflen);
158 157
159 if (IS_ERR(pos)) 158 if (IS_ERR(pos))
160 return pos; 159 return pos;
161 /* Convert from $PID to self if $PID i 160 /* Convert from $PID to self if $PID is current thread. */
162 if (sb->s_magic == PROC_SUPER_MAGIC && 161 if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') {
163 char *ep; 162 char *ep;
164 const pid_t pid = (pid_t) simp 163 const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10);
165 struct pid_namespace *proc_pid <<
166 164
167 if (*ep == '/' && pid && pid = 165 if (*ep == '/' && pid && pid ==
168 task_tgid_nr_ns(current, p !! 166 task_tgid_nr_ns(current, sb->s_fs_info)) {
169 pos = ep - 5; 167 pos = ep - 5;
170 if (pos < buffer) 168 if (pos < buffer)
171 goto out; 169 goto out;
172 memmove(pos, "/self", 170 memmove(pos, "/self", 5);
173 } 171 }
174 goto prepend_filesystem_name; 172 goto prepend_filesystem_name;
175 } 173 }
176 /* Use filesystem name for unnamed dev 174 /* Use filesystem name for unnamed devices. */
177 if (!MAJOR(sb->s_dev)) 175 if (!MAJOR(sb->s_dev))
178 goto prepend_filesystem_name; 176 goto prepend_filesystem_name;
179 { 177 {
180 struct inode *inode = d_backin 178 struct inode *inode = d_backing_inode(sb->s_root);
181 179
182 /* 180 /*
183 * Use filesystem name if file 181 * Use filesystem name if filesystem does not support rename()
184 * operation. 182 * operation.
185 */ 183 */
186 if (!inode->i_op->rename) 184 if (!inode->i_op->rename)
187 goto prepend_filesyste 185 goto prepend_filesystem_name;
188 } 186 }
189 /* Prepend device name. */ 187 /* Prepend device name. */
190 { 188 {
191 char name[64]; 189 char name[64];
192 int name_len; 190 int name_len;
193 const dev_t dev = sb->s_dev; 191 const dev_t dev = sb->s_dev;
194 192
195 name[sizeof(name) - 1] = '\0'; 193 name[sizeof(name) - 1] = '\0';
196 snprintf(name, sizeof(name) - 194 snprintf(name, sizeof(name) - 1, "dev(%u,%u):", MAJOR(dev),
197 MINOR(dev)); 195 MINOR(dev));
198 name_len = strlen(name); 196 name_len = strlen(name);
199 pos -= name_len; 197 pos -= name_len;
200 if (pos < buffer) 198 if (pos < buffer)
201 goto out; 199 goto out;
202 memmove(pos, name, name_len); 200 memmove(pos, name, name_len);
203 return pos; 201 return pos;
204 } 202 }
205 /* Prepend filesystem name. */ 203 /* Prepend filesystem name. */
206 prepend_filesystem_name: 204 prepend_filesystem_name:
207 { 205 {
208 const char *name = sb->s_type- 206 const char *name = sb->s_type->name;
209 const int name_len = strlen(na 207 const int name_len = strlen(name);
210 208
211 pos -= name_len + 1; 209 pos -= name_len + 1;
212 if (pos < buffer) 210 if (pos < buffer)
213 goto out; 211 goto out;
214 memmove(pos, name, name_len); 212 memmove(pos, name, name_len);
215 pos[name_len] = ':'; 213 pos[name_len] = ':';
216 } 214 }
217 return pos; 215 return pos;
218 out: 216 out:
219 return ERR_PTR(-ENOMEM); 217 return ERR_PTR(-ENOMEM);
220 } 218 }
221 219
222 /** 220 /**
223 * tomoyo_realpath_from_path - Returns realpat 221 * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
224 * 222 *
225 * @path: Pointer to "struct path". 223 * @path: Pointer to "struct path".
226 * 224 *
227 * Returns the realpath of the given @path on 225 * Returns the realpath of the given @path on success, NULL otherwise.
228 * 226 *
229 * If dentry is a directory, trailing '/' is a 227 * If dentry is a directory, trailing '/' is appended.
230 * Characters out of 0x20 < c < 0x7F range are 228 * Characters out of 0x20 < c < 0x7F range are converted to
231 * \ooo style octal string. 229 * \ooo style octal string.
232 * Character \ is converted to \\ string. 230 * Character \ is converted to \\ string.
233 * 231 *
234 * These functions use kzalloc(), so the calle 232 * These functions use kzalloc(), so the caller must call kfree()
235 * if these functions didn't return NULL. 233 * if these functions didn't return NULL.
236 */ 234 */
237 char *tomoyo_realpath_from_path(const struct p 235 char *tomoyo_realpath_from_path(const struct path *path)
238 { 236 {
239 char *buf = NULL; 237 char *buf = NULL;
240 char *name = NULL; 238 char *name = NULL;
241 unsigned int buf_len = PAGE_SIZE / 2; 239 unsigned int buf_len = PAGE_SIZE / 2;
242 struct dentry *dentry = path->dentry; 240 struct dentry *dentry = path->dentry;
243 struct super_block *sb = dentry->d_sb; !! 241 struct super_block *sb;
244 242
>> 243 if (!dentry)
>> 244 return NULL;
>> 245 sb = dentry->d_sb;
245 while (1) { 246 while (1) {
246 char *pos; 247 char *pos;
247 struct inode *inode; 248 struct inode *inode;
248 249
249 buf_len <<= 1; 250 buf_len <<= 1;
250 kfree(buf); 251 kfree(buf);
251 buf = kmalloc(buf_len, GFP_NOF 252 buf = kmalloc(buf_len, GFP_NOFS);
252 if (!buf) 253 if (!buf)
253 break; 254 break;
254 /* To make sure that pos is '\ 255 /* To make sure that pos is '\0' terminated. */
255 buf[buf_len - 1] = '\0'; 256 buf[buf_len - 1] = '\0';
256 /* For "pipe:[\$]" and "socket 257 /* For "pipe:[\$]" and "socket:[\$]". */
257 if (dentry->d_op && dentry->d_ 258 if (dentry->d_op && dentry->d_op->d_dname) {
258 pos = dentry->d_op->d_ 259 pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1);
259 goto encode; 260 goto encode;
260 } 261 }
261 inode = d_backing_inode(sb->s_ 262 inode = d_backing_inode(sb->s_root);
262 /* 263 /*
263 * Get local name for filesyst 264 * Get local name for filesystems without rename() operation
>> 265 * or dentry without vfsmount.
264 */ 266 */
265 if ((!inode->i_op->rename && !! 267 if (!path->mnt ||
>> 268 (!inode->i_op->rename &&
266 !(sb->s_type->fs_flags & 269 !(sb->s_type->fs_flags & FS_REQUIRES_DEV)))
267 pos = tomoyo_get_local 270 pos = tomoyo_get_local_path(path->dentry, buf,
268 271 buf_len - 1);
269 /* Get absolute name for the r 272 /* Get absolute name for the rest. */
270 else { 273 else {
271 pos = tomoyo_get_absol 274 pos = tomoyo_get_absolute_path(path, buf, buf_len - 1);
272 /* 275 /*
273 * Fall back to local 276 * Fall back to local name if absolute name is not
274 * available. 277 * available.
275 */ 278 */
276 if (pos == ERR_PTR(-EI 279 if (pos == ERR_PTR(-EINVAL))
277 pos = tomoyo_g 280 pos = tomoyo_get_local_path(path->dentry, buf,
278 281 buf_len - 1);
279 } 282 }
280 encode: 283 encode:
281 if (IS_ERR(pos)) 284 if (IS_ERR(pos))
282 continue; 285 continue;
283 name = tomoyo_encode(pos); 286 name = tomoyo_encode(pos);
284 break; 287 break;
285 } 288 }
286 kfree(buf); 289 kfree(buf);
287 if (!name) 290 if (!name)
288 tomoyo_warn_oom(__func__); 291 tomoyo_warn_oom(__func__);
289 return name; 292 return name;
290 } 293 }
291 294
292 /** 295 /**
293 * tomoyo_realpath_nofollow - Get realpath of 296 * tomoyo_realpath_nofollow - Get realpath of a pathname.
294 * 297 *
295 * @pathname: The pathname to solve. 298 * @pathname: The pathname to solve.
296 * 299 *
297 * Returns the realpath of @pathname on succes 300 * Returns the realpath of @pathname on success, NULL otherwise.
298 */ 301 */
299 char *tomoyo_realpath_nofollow(const char *pat 302 char *tomoyo_realpath_nofollow(const char *pathname)
300 { 303 {
301 struct path path; 304 struct path path;
302 305
303 if (pathname && kern_path(pathname, 0, 306 if (pathname && kern_path(pathname, 0, &path) == 0) {
304 char *buf = tomoyo_realpath_fr 307 char *buf = tomoyo_realpath_from_path(&path);
305 308
306 path_put(&path); 309 path_put(&path);
307 return buf; 310 return buf;
308 } 311 }
309 return NULL; 312 return NULL;
310 } 313 }
311 314
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TOMOYO® is a registered trademark of NTT DATA CORPORATION.