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Commit | Line | Data |
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c73bd6d4 KT |
1 | /* |
2 | * security/tomoyo/realpath.c | |
3 | * | |
4 | * Get the canonicalized absolute pathnames. The basis for TOMOYO. | |
5 | * | |
6 | * Copyright (C) 2005-2009 NTT DATA CORPORATION | |
7 | * | |
39826a1e | 8 | * Version: 2.2.0 2009/04/01 |
c73bd6d4 KT |
9 | * |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/mount.h> | |
14 | #include <linux/mnt_namespace.h> | |
5ad4e53b | 15 | #include <linux/fs_struct.h> |
024e1a49 | 16 | #include <linux/hash.h> |
67fa4880 | 17 | #include <linux/magic.h> |
c73bd6d4 | 18 | #include "common.h" |
c73bd6d4 KT |
19 | |
20 | /** | |
21 | * tomoyo_encode: Convert binary string to ascii string. | |
22 | * | |
23 | * @buffer: Buffer for ASCII string. | |
24 | * @buflen: Size of @buffer. | |
25 | * @str: Binary string. | |
26 | * | |
27 | * Returns 0 on success, -ENOMEM otherwise. | |
28 | */ | |
29 | int tomoyo_encode(char *buffer, int buflen, const char *str) | |
30 | { | |
31 | while (1) { | |
32 | const unsigned char c = *(unsigned char *) str++; | |
33 | ||
34 | if (tomoyo_is_valid(c)) { | |
35 | if (--buflen <= 0) | |
36 | break; | |
37 | *buffer++ = (char) c; | |
38 | if (c != '\\') | |
39 | continue; | |
40 | if (--buflen <= 0) | |
41 | break; | |
42 | *buffer++ = (char) c; | |
43 | continue; | |
44 | } | |
45 | if (!c) { | |
46 | if (--buflen <= 0) | |
47 | break; | |
48 | *buffer = '\0'; | |
49 | return 0; | |
50 | } | |
51 | buflen -= 4; | |
52 | if (buflen <= 0) | |
53 | break; | |
54 | *buffer++ = '\\'; | |
55 | *buffer++ = (c >> 6) + '0'; | |
56 | *buffer++ = ((c >> 3) & 7) + '0'; | |
57 | *buffer++ = (c & 7) + '0'; | |
58 | } | |
59 | return -ENOMEM; | |
60 | } | |
61 | ||
62 | /** | |
63 | * tomoyo_realpath_from_path2 - Returns realpath(3) of the given dentry but ignores chroot'ed root. | |
64 | * | |
65 | * @path: Pointer to "struct path". | |
66 | * @newname: Pointer to buffer to return value in. | |
67 | * @newname_len: Size of @newname. | |
68 | * | |
69 | * Returns 0 on success, negative value otherwise. | |
70 | * | |
71 | * If dentry is a directory, trailing '/' is appended. | |
72 | * Characters out of 0x20 < c < 0x7F range are converted to | |
73 | * \ooo style octal string. | |
74 | * Character \ is converted to \\ string. | |
75 | */ | |
76 | int tomoyo_realpath_from_path2(struct path *path, char *newname, | |
77 | int newname_len) | |
78 | { | |
79 | int error = -ENOMEM; | |
80 | struct dentry *dentry = path->dentry; | |
81 | char *sp; | |
82 | ||
83 | if (!dentry || !path->mnt || !newname || newname_len <= 2048) | |
84 | return -EINVAL; | |
85 | if (dentry->d_op && dentry->d_op->d_dname) { | |
86 | /* For "socket:[\$]" and "pipe:[\$]". */ | |
87 | static const int offset = 1536; | |
88 | sp = dentry->d_op->d_dname(dentry, newname + offset, | |
89 | newname_len - offset); | |
90 | } else { | |
37afdc79 | 91 | struct path ns_root = {.mnt = NULL, .dentry = NULL}; |
c73bd6d4 | 92 | |
c73bd6d4 | 93 | spin_lock(&dcache_lock); |
37afdc79 AV |
94 | /* go to whatever namespace root we are under */ |
95 | sp = __d_path(path, &ns_root, newname, newname_len); | |
c73bd6d4 | 96 | spin_unlock(&dcache_lock); |
a4054b6b | 97 | /* Prepend "/proc" prefix if using internal proc vfs mount. */ |
440b3c6c | 98 | if (!IS_ERR(sp) && (path->mnt->mnt_flags & MNT_INTERNAL) && |
67fa4880 | 99 | (path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC)) { |
a4054b6b EB |
100 | sp -= 5; |
101 | if (sp >= newname) | |
102 | memcpy(sp, "/proc", 5); | |
103 | else | |
104 | sp = ERR_PTR(-ENOMEM); | |
105 | } | |
c73bd6d4 KT |
106 | } |
107 | if (IS_ERR(sp)) | |
108 | error = PTR_ERR(sp); | |
109 | else | |
110 | error = tomoyo_encode(newname, sp - newname, sp); | |
111 | /* Append trailing '/' if dentry is a directory. */ | |
112 | if (!error && dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode) | |
113 | && *newname) { | |
114 | sp = newname + strlen(newname); | |
115 | if (*(sp - 1) != '/') { | |
116 | if (sp < newname + newname_len - 4) { | |
117 | *sp++ = '/'; | |
118 | *sp = '\0'; | |
119 | } else { | |
120 | error = -ENOMEM; | |
121 | } | |
122 | } | |
123 | } | |
124 | if (error) | |
125 | printk(KERN_WARNING "tomoyo_realpath: Pathname too long.\n"); | |
126 | return error; | |
127 | } | |
128 | ||
129 | /** | |
130 | * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root. | |
131 | * | |
132 | * @path: Pointer to "struct path". | |
133 | * | |
134 | * Returns the realpath of the given @path on success, NULL otherwise. | |
135 | * | |
8e2d39a1 | 136 | * These functions use kzalloc(), so the caller must call kfree() |
c73bd6d4 KT |
137 | * if these functions didn't return NULL. |
138 | */ | |
139 | char *tomoyo_realpath_from_path(struct path *path) | |
140 | { | |
4e5d6f7e | 141 | char *buf = kzalloc(sizeof(struct tomoyo_page_buffer), GFP_NOFS); |
c73bd6d4 KT |
142 | |
143 | BUILD_BUG_ON(sizeof(struct tomoyo_page_buffer) | |
144 | <= TOMOYO_MAX_PATHNAME_LEN - 1); | |
145 | if (!buf) | |
146 | return NULL; | |
147 | if (tomoyo_realpath_from_path2(path, buf, | |
148 | TOMOYO_MAX_PATHNAME_LEN - 1) == 0) | |
149 | return buf; | |
8e2d39a1 | 150 | kfree(buf); |
c73bd6d4 KT |
151 | return NULL; |
152 | } | |
153 | ||
154 | /** | |
155 | * tomoyo_realpath - Get realpath of a pathname. | |
156 | * | |
157 | * @pathname: The pathname to solve. | |
158 | * | |
159 | * Returns the realpath of @pathname on success, NULL otherwise. | |
160 | */ | |
161 | char *tomoyo_realpath(const char *pathname) | |
162 | { | |
e24977d4 | 163 | struct path path; |
c73bd6d4 | 164 | |
e24977d4 AV |
165 | if (pathname && kern_path(pathname, LOOKUP_FOLLOW, &path) == 0) { |
166 | char *buf = tomoyo_realpath_from_path(&path); | |
167 | path_put(&path); | |
c73bd6d4 KT |
168 | return buf; |
169 | } | |
170 | return NULL; | |
171 | } | |
172 | ||
173 | /** | |
174 | * tomoyo_realpath_nofollow - Get realpath of a pathname. | |
175 | * | |
176 | * @pathname: The pathname to solve. | |
177 | * | |
178 | * Returns the realpath of @pathname on success, NULL otherwise. | |
179 | */ | |
180 | char *tomoyo_realpath_nofollow(const char *pathname) | |
181 | { | |
e24977d4 | 182 | struct path path; |
c73bd6d4 | 183 | |
e24977d4 AV |
184 | if (pathname && kern_path(pathname, 0, &path) == 0) { |
185 | char *buf = tomoyo_realpath_from_path(&path); | |
186 | path_put(&path); | |
c73bd6d4 KT |
187 | return buf; |
188 | } | |
189 | return NULL; | |
190 | } | |
191 | ||
192 | /* Memory allocated for non-string data. */ | |
847b173e TH |
193 | static atomic_t tomoyo_policy_memory_size; |
194 | /* Quota for holding policy. */ | |
195 | static unsigned int tomoyo_quota_for_policy; | |
c73bd6d4 KT |
196 | |
197 | /** | |
cd7bec6a | 198 | * tomoyo_memory_ok - Check memory quota. |
c73bd6d4 | 199 | * |
cd7bec6a | 200 | * @ptr: Pointer to allocated memory. |
c73bd6d4 | 201 | * |
cd7bec6a | 202 | * Returns true on success, false otherwise. |
c73bd6d4 | 203 | * |
cd7bec6a TH |
204 | * Caller holds tomoyo_policy_lock. |
205 | * Memory pointed by @ptr will be zeroed on success. | |
c73bd6d4 | 206 | */ |
cd7bec6a | 207 | bool tomoyo_memory_ok(void *ptr) |
c73bd6d4 | 208 | { |
cd7bec6a | 209 | int allocated_len = ptr ? ksize(ptr) : 0; |
847b173e TH |
210 | atomic_add(allocated_len, &tomoyo_policy_memory_size); |
211 | if (ptr && (!tomoyo_quota_for_policy || | |
212 | atomic_read(&tomoyo_policy_memory_size) | |
213 | <= tomoyo_quota_for_policy)) { | |
cd7bec6a | 214 | memset(ptr, 0, allocated_len); |
847b173e | 215 | return true; |
c73bd6d4 | 216 | } |
847b173e TH |
217 | printk(KERN_WARNING "ERROR: Out of memory " |
218 | "for tomoyo_alloc_element().\n"); | |
219 | if (!tomoyo_policy_loaded) | |
220 | panic("MAC Initialization failed.\n"); | |
221 | return false; | |
c73bd6d4 KT |
222 | } |
223 | ||
847b173e TH |
224 | /** |
225 | * tomoyo_memory_free - Free memory for elements. | |
226 | * | |
227 | * @ptr: Pointer to allocated memory. | |
228 | */ | |
229 | void tomoyo_memory_free(void *ptr) | |
230 | { | |
231 | atomic_sub(ksize(ptr), &tomoyo_policy_memory_size); | |
232 | kfree(ptr); | |
233 | } | |
c73bd6d4 | 234 | |
c73bd6d4 | 235 | /* |
c3fa109a TH |
236 | * tomoyo_name_list is used for holding string data used by TOMOYO. |
237 | * Since same string data is likely used for multiple times (e.g. | |
238 | * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of | |
239 | * "const struct tomoyo_path_info *". | |
c73bd6d4 | 240 | */ |
847b173e TH |
241 | struct list_head tomoyo_name_list[TOMOYO_MAX_HASH]; |
242 | /* Lock for protecting tomoyo_name_list . */ | |
243 | DEFINE_MUTEX(tomoyo_name_list_lock); | |
c73bd6d4 KT |
244 | |
245 | /** | |
bf24fb01 | 246 | * tomoyo_get_name - Allocate permanent memory for string data. |
c73bd6d4 KT |
247 | * |
248 | * @name: The string to store into the permernent memory. | |
249 | * | |
250 | * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise. | |
c73bd6d4 | 251 | */ |
bf24fb01 | 252 | const struct tomoyo_path_info *tomoyo_get_name(const char *name) |
c73bd6d4 | 253 | { |
c73bd6d4 KT |
254 | struct tomoyo_name_entry *ptr; |
255 | unsigned int hash; | |
c73bd6d4 | 256 | int len; |
e41035a9 | 257 | int allocated_len; |
024e1a49 | 258 | struct list_head *head; |
c73bd6d4 KT |
259 | |
260 | if (!name) | |
261 | return NULL; | |
262 | len = strlen(name) + 1; | |
c73bd6d4 | 263 | hash = full_name_hash((const unsigned char *) name, len - 1); |
024e1a49 | 264 | head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)]; |
847b173e | 265 | mutex_lock(&tomoyo_name_list_lock); |
024e1a49 | 266 | list_for_each_entry(ptr, head, list) { |
bf24fb01 TH |
267 | if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name)) |
268 | continue; | |
269 | atomic_inc(&ptr->users); | |
270 | goto out; | |
c73bd6d4 | 271 | } |
4e5d6f7e | 272 | ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS); |
e41035a9 | 273 | allocated_len = ptr ? ksize(ptr) : 0; |
847b173e TH |
274 | if (!ptr || (tomoyo_quota_for_policy && |
275 | atomic_read(&tomoyo_policy_memory_size) + allocated_len | |
276 | > tomoyo_quota_for_policy)) { | |
e41035a9 | 277 | kfree(ptr); |
c73bd6d4 | 278 | printk(KERN_WARNING "ERROR: Out of memory " |
bf24fb01 | 279 | "for tomoyo_get_name().\n"); |
c73bd6d4 KT |
280 | if (!tomoyo_policy_loaded) |
281 | panic("MAC Initialization failed.\n"); | |
282 | ptr = NULL; | |
283 | goto out; | |
284 | } | |
847b173e | 285 | atomic_add(allocated_len, &tomoyo_policy_memory_size); |
e41035a9 TH |
286 | ptr->entry.name = ((char *) ptr) + sizeof(*ptr); |
287 | memmove((char *) ptr->entry.name, name, len); | |
bf24fb01 | 288 | atomic_set(&ptr->users, 1); |
c73bd6d4 | 289 | tomoyo_fill_path_info(&ptr->entry); |
024e1a49 | 290 | list_add_tail(&ptr->list, head); |
c73bd6d4 | 291 | out: |
847b173e | 292 | mutex_unlock(&tomoyo_name_list_lock); |
c73bd6d4 KT |
293 | return ptr ? &ptr->entry : NULL; |
294 | } | |
295 | ||
296 | /** | |
297 | * tomoyo_realpath_init - Initialize realpath related code. | |
c73bd6d4 | 298 | */ |
1581e7dd | 299 | void __init tomoyo_realpath_init(void) |
c73bd6d4 KT |
300 | { |
301 | int i; | |
302 | ||
303 | BUILD_BUG_ON(TOMOYO_MAX_PATHNAME_LEN > PATH_MAX); | |
304 | for (i = 0; i < TOMOYO_MAX_HASH; i++) | |
305 | INIT_LIST_HEAD(&tomoyo_name_list[i]); | |
306 | INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list); | |
bf24fb01 | 307 | tomoyo_kernel_domain.domainname = tomoyo_get_name(TOMOYO_ROOT_NAME); |
fdb8ebb7 TH |
308 | /* |
309 | * tomoyo_read_lock() is not needed because this function is | |
310 | * called before the first "delete" request. | |
311 | */ | |
312 | list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list); | |
c73bd6d4 KT |
313 | if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain) |
314 | panic("Can't register tomoyo_kernel_domain"); | |
c73bd6d4 KT |
315 | } |
316 | ||
c73bd6d4 KT |
317 | /** |
318 | * tomoyo_read_memory_counter - Check for memory usage in bytes. | |
319 | * | |
320 | * @head: Pointer to "struct tomoyo_io_buffer". | |
321 | * | |
322 | * Returns memory usage. | |
323 | */ | |
324 | int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head) | |
325 | { | |
326 | if (!head->read_eof) { | |
847b173e TH |
327 | const unsigned int policy |
328 | = atomic_read(&tomoyo_policy_memory_size); | |
c73bd6d4 KT |
329 | char buffer[64]; |
330 | ||
331 | memset(buffer, 0, sizeof(buffer)); | |
847b173e | 332 | if (tomoyo_quota_for_policy) |
c73bd6d4 KT |
333 | snprintf(buffer, sizeof(buffer) - 1, |
334 | " (Quota: %10u)", | |
847b173e | 335 | tomoyo_quota_for_policy); |
c73bd6d4 KT |
336 | else |
337 | buffer[0] = '\0'; | |
847b173e TH |
338 | tomoyo_io_printf(head, "Policy: %10u%s\n", policy, buffer); |
339 | tomoyo_io_printf(head, "Total: %10u\n", policy); | |
c73bd6d4 KT |
340 | head->read_eof = true; |
341 | } | |
342 | return 0; | |
343 | } | |
344 | ||
345 | /** | |
346 | * tomoyo_write_memory_quota - Set memory quota. | |
347 | * | |
348 | * @head: Pointer to "struct tomoyo_io_buffer". | |
349 | * | |
350 | * Returns 0. | |
351 | */ | |
352 | int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head) | |
353 | { | |
354 | char *data = head->write_buf; | |
355 | unsigned int size; | |
356 | ||
847b173e TH |
357 | if (sscanf(data, "Policy: %u", &size) == 1) |
358 | tomoyo_quota_for_policy = size; | |
c73bd6d4 KT |
359 | return 0; |
360 | } |