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