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-rw-r--r--security/tomoyo/realpath.c426
1 files changed, 114 insertions, 312 deletions
diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c
index d1b96f019621..ed8ccd680102 100644
--- a/security/tomoyo/realpath.c
+++ b/security/tomoyo/realpath.c
@@ -1,174 +1,164 @@
1/* 1/*
2 * security/tomoyo/realpath.c 2 * security/tomoyo/realpath.c
3 * 3 *
4 * Get the canonicalized absolute pathnames. The basis for TOMOYO. 4 * Pathname calculation functions for TOMOYO.
5 *
6 * Copyright (C) 2005-2009 NTT DATA CORPORATION
7 *
8 * Version: 2.2.0 2009/04/01
9 * 5 *
6 * Copyright (C) 2005-2010 NTT DATA CORPORATION
10 */ 7 */
11 8
12#include <linux/types.h> 9#include <linux/types.h>
13#include <linux/mount.h> 10#include <linux/mount.h>
14#include <linux/mnt_namespace.h> 11#include <linux/mnt_namespace.h>
15#include <linux/fs_struct.h> 12#include <linux/fs_struct.h>
16#include <linux/hash.h>
17#include <linux/magic.h> 13#include <linux/magic.h>
18#include <linux/slab.h> 14#include <linux/slab.h>
15#include <net/sock.h>
19#include "common.h" 16#include "common.h"
20 17
21/** 18/**
22 * tomoyo_encode: Convert binary string to ascii string. 19 * tomoyo_encode: Convert binary string to ascii string.
23 * 20 *
24 * @buffer: Buffer for ASCII string. 21 * @str: String in binary format.
25 * @buflen: Size of @buffer. 22 *
26 * @str: Binary string. 23 * Returns pointer to @str in ascii format on success, NULL otherwise.
27 * 24 *
28 * Returns 0 on success, -ENOMEM otherwise. 25 * This function uses kzalloc(), so caller must kfree() if this function
26 * didn't return NULL.
29 */ 27 */
30int tomoyo_encode(char *buffer, int buflen, const char *str) 28char *tomoyo_encode(const char *str)
31{ 29{
32 while (1) { 30 int len = 0;
33 const unsigned char c = *(unsigned char *) str++; 31 const char *p = str;
32 char *cp;
33 char *cp0;
34 34
35 if (tomoyo_is_valid(c)) { 35 if (!p)
36 if (--buflen <= 0) 36 return NULL;
37 break; 37 while (*p) {
38 *buffer++ = (char) c; 38 const unsigned char c = *p++;
39 if (c != '\\') 39 if (c == '\\')
40 continue; 40 len += 2;
41 if (--buflen <= 0) 41 else if (c > ' ' && c < 127)
42 break; 42 len++;
43 *buffer++ = (char) c; 43 else
44 continue; 44 len += 4;
45 } 45 }
46 if (!c) { 46 len++;
47 if (--buflen <= 0) 47 /* Reserve space for appending "/". */
48 break; 48 cp = kzalloc(len + 10, GFP_NOFS);
49 *buffer = '\0'; 49 if (!cp)
50 return 0; 50 return NULL;
51 cp0 = cp;
52 p = str;
53 while (*p) {
54 const unsigned char c = *p++;
55
56 if (c == '\\') {
57 *cp++ = '\\';
58 *cp++ = '\\';
59 } else if (c > ' ' && c < 127) {
60 *cp++ = c;
61 } else {
62 *cp++ = '\\';
63 *cp++ = (c >> 6) + '0';
64 *cp++ = ((c >> 3) & 7) + '0';
65 *cp++ = (c & 7) + '0';
51 } 66 }
52 buflen -= 4;
53 if (buflen <= 0)
54 break;
55 *buffer++ = '\\';
56 *buffer++ = (c >> 6) + '0';
57 *buffer++ = ((c >> 3) & 7) + '0';
58 *buffer++ = (c & 7) + '0';
59 } 67 }
60 return -ENOMEM; 68 return cp0;
61} 69}
62 70
63/** 71/**
64 * tomoyo_realpath_from_path2 - Returns realpath(3) of the given dentry but ignores chroot'ed root. 72 * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
65 * 73 *
66 * @path: Pointer to "struct path". 74 * @path: Pointer to "struct path".
67 * @newname: Pointer to buffer to return value in.
68 * @newname_len: Size of @newname.
69 * 75 *
70 * Returns 0 on success, negative value otherwise. 76 * Returns the realpath of the given @path on success, NULL otherwise.
71 * 77 *
72 * If dentry is a directory, trailing '/' is appended. 78 * If dentry is a directory, trailing '/' is appended.
73 * Characters out of 0x20 < c < 0x7F range are converted to 79 * Characters out of 0x20 < c < 0x7F range are converted to
74 * \ooo style octal string. 80 * \ooo style octal string.
75 * Character \ is converted to \\ string. 81 * Character \ is converted to \\ string.
82 *
83 * These functions use kzalloc(), so the caller must call kfree()
84 * if these functions didn't return NULL.
76 */ 85 */
77int tomoyo_realpath_from_path2(struct path *path, char *newname, 86char *tomoyo_realpath_from_path(struct path *path)
78 int newname_len)
79{ 87{
80 int error = -ENOMEM; 88 char *buf = NULL;
89 char *name = NULL;
90 unsigned int buf_len = PAGE_SIZE / 2;
81 struct dentry *dentry = path->dentry; 91 struct dentry *dentry = path->dentry;
82 char *sp; 92 bool is_dir;
83 93 if (!dentry)
84 if (!dentry || !path->mnt || !newname || newname_len <= 2048) 94 return NULL;
85 return -EINVAL; 95 is_dir = dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode);
86 if (dentry->d_op && dentry->d_op->d_dname) { 96 while (1) {
97 struct path ns_root = { .mnt = NULL, .dentry = NULL };
98 char *pos;
99 buf_len <<= 1;
100 kfree(buf);
101 buf = kmalloc(buf_len, GFP_NOFS);
102 if (!buf)
103 break;
104 /* Get better name for socket. */
105 if (dentry->d_sb && dentry->d_sb->s_magic == SOCKFS_MAGIC) {
106 struct inode *inode = dentry->d_inode;
107 struct socket *sock = inode ? SOCKET_I(inode) : NULL;
108 struct sock *sk = sock ? sock->sk : NULL;
109 if (sk) {
110 snprintf(buf, buf_len - 1, "socket:[family=%u:"
111 "type=%u:protocol=%u]", sk->sk_family,
112 sk->sk_type, sk->sk_protocol);
113 } else {
114 snprintf(buf, buf_len - 1, "socket:[unknown]");
115 }
116 name = tomoyo_encode(buf);
117 break;
118 }
87 /* For "socket:[\$]" and "pipe:[\$]". */ 119 /* For "socket:[\$]" and "pipe:[\$]". */
88 static const int offset = 1536; 120 if (dentry->d_op && dentry->d_op->d_dname) {
89 sp = dentry->d_op->d_dname(dentry, newname + offset, 121 pos = dentry->d_op->d_dname(dentry, buf, buf_len - 1);
90 newname_len - offset); 122 if (IS_ERR(pos))
91 } else { 123 continue;
92 struct path ns_root = {.mnt = NULL, .dentry = NULL}; 124 name = tomoyo_encode(pos);
93 125 break;
126 }
127 /* If we don't have a vfsmount, we can't calculate. */
128 if (!path->mnt)
129 break;
94 spin_lock(&dcache_lock); 130 spin_lock(&dcache_lock);
95 /* go to whatever namespace root we are under */ 131 /* go to whatever namespace root we are under */
96 sp = __d_path(path, &ns_root, newname, newname_len); 132 pos = __d_path(path, &ns_root, buf, buf_len);
97 spin_unlock(&dcache_lock); 133 spin_unlock(&dcache_lock);
98 /* Prepend "/proc" prefix if using internal proc vfs mount. */ 134 /* Prepend "/proc" prefix if using internal proc vfs mount. */
99 if (!IS_ERR(sp) && (path->mnt->mnt_flags & MNT_INTERNAL) && 135 if (!IS_ERR(pos) && (path->mnt->mnt_flags & MNT_INTERNAL) &&
100 (path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC)) { 136 (path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC)) {
101 sp -= 5; 137 pos -= 5;
102 if (sp >= newname) 138 if (pos >= buf)
103 memcpy(sp, "/proc", 5); 139 memcpy(pos, "/proc", 5);
104 else 140 else
105 sp = ERR_PTR(-ENOMEM); 141 pos = ERR_PTR(-ENOMEM);
106 }
107 }
108 if (IS_ERR(sp))
109 error = PTR_ERR(sp);
110 else
111 error = tomoyo_encode(newname, sp - newname, sp);
112 /* Append trailing '/' if dentry is a directory. */
113 if (!error && dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)
114 && *newname) {
115 sp = newname + strlen(newname);
116 if (*(sp - 1) != '/') {
117 if (sp < newname + newname_len - 4) {
118 *sp++ = '/';
119 *sp = '\0';
120 } else {
121 error = -ENOMEM;
122 }
123 } 142 }
143 if (IS_ERR(pos))
144 continue;
145 name = tomoyo_encode(pos);
146 break;
124 } 147 }
125 if (error)
126 printk(KERN_WARNING "tomoyo_realpath: Pathname too long.\n");
127 return error;
128}
129
130/**
131 * tomoyo_realpath_from_path - Returns realpath(3) of the given pathname but ignores chroot'ed root.
132 *
133 * @path: Pointer to "struct path".
134 *
135 * Returns the realpath of the given @path on success, NULL otherwise.
136 *
137 * These functions use kzalloc(), so the caller must call kfree()
138 * if these functions didn't return NULL.
139 */
140char *tomoyo_realpath_from_path(struct path *path)
141{
142 char *buf = kzalloc(sizeof(struct tomoyo_page_buffer), GFP_NOFS);
143
144 BUILD_BUG_ON(sizeof(struct tomoyo_page_buffer)
145 <= TOMOYO_MAX_PATHNAME_LEN - 1);
146 if (!buf)
147 return NULL;
148 if (tomoyo_realpath_from_path2(path, buf,
149 TOMOYO_MAX_PATHNAME_LEN - 1) == 0)
150 return buf;
151 kfree(buf); 148 kfree(buf);
152 return NULL; 149 if (!name)
153} 150 tomoyo_warn_oom(__func__);
154 151 else if (is_dir && *name) {
155/** 152 /* Append trailing '/' if dentry is a directory. */
156 * tomoyo_realpath - Get realpath of a pathname. 153 char *pos = name + strlen(name) - 1;
157 * 154 if (*pos != '/')
158 * @pathname: The pathname to solve. 155 /*
159 * 156 * This is OK because tomoyo_encode() reserves space
160 * Returns the realpath of @pathname on success, NULL otherwise. 157 * for appending "/".
161 */ 158 */
162char *tomoyo_realpath(const char *pathname) 159 *++pos = '/';
163{
164 struct path path;
165
166 if (pathname && kern_path(pathname, LOOKUP_FOLLOW, &path) == 0) {
167 char *buf = tomoyo_realpath_from_path(&path);
168 path_put(&path);
169 return buf;
170 } 160 }
171 return NULL; 161 return name;
172} 162}
173 163
174/** 164/**
@@ -189,191 +179,3 @@ char *tomoyo_realpath_nofollow(const char *pathname)
189 } 179 }
190 return NULL; 180 return NULL;
191} 181}
192
193/* Memory allocated for non-string data. */
194static atomic_t tomoyo_policy_memory_size;
195/* Quota for holding policy. */
196static unsigned int tomoyo_quota_for_policy;
197
198/**
199 * tomoyo_memory_ok - Check memory quota.
200 *
201 * @ptr: Pointer to allocated memory.
202 *
203 * Returns true on success, false otherwise.
204 *
205 * Caller holds tomoyo_policy_lock.
206 * Memory pointed by @ptr will be zeroed on success.
207 */
208bool tomoyo_memory_ok(void *ptr)
209{
210 int allocated_len = ptr ? ksize(ptr) : 0;
211 atomic_add(allocated_len, &tomoyo_policy_memory_size);
212 if (ptr && (!tomoyo_quota_for_policy ||
213 atomic_read(&tomoyo_policy_memory_size)
214 <= tomoyo_quota_for_policy)) {
215 memset(ptr, 0, allocated_len);
216 return true;
217 }
218 printk(KERN_WARNING "ERROR: Out of memory "
219 "for tomoyo_alloc_element().\n");
220 if (!tomoyo_policy_loaded)
221 panic("MAC Initialization failed.\n");
222 return false;
223}
224
225/**
226 * tomoyo_commit_ok - Check memory quota.
227 *
228 * @data: Data to copy from.
229 * @size: Size in byte.
230 *
231 * Returns pointer to allocated memory on success, NULL otherwise.
232 */
233void *tomoyo_commit_ok(void *data, const unsigned int size)
234{
235 void *ptr = kzalloc(size, GFP_NOFS);
236 if (tomoyo_memory_ok(ptr)) {
237 memmove(ptr, data, size);
238 memset(data, 0, size);
239 return ptr;
240 }
241 return NULL;
242}
243
244/**
245 * tomoyo_memory_free - Free memory for elements.
246 *
247 * @ptr: Pointer to allocated memory.
248 */
249void tomoyo_memory_free(void *ptr)
250{
251 atomic_sub(ksize(ptr), &tomoyo_policy_memory_size);
252 kfree(ptr);
253}
254
255/*
256 * tomoyo_name_list is used for holding string data used by TOMOYO.
257 * Since same string data is likely used for multiple times (e.g.
258 * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
259 * "const struct tomoyo_path_info *".
260 */
261struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
262
263/**
264 * tomoyo_get_name - Allocate permanent memory for string data.
265 *
266 * @name: The string to store into the permernent memory.
267 *
268 * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
269 */
270const struct tomoyo_path_info *tomoyo_get_name(const char *name)
271{
272 struct tomoyo_name_entry *ptr;
273 unsigned int hash;
274 int len;
275 int allocated_len;
276 struct list_head *head;
277
278 if (!name)
279 return NULL;
280 len = strlen(name) + 1;
281 hash = full_name_hash((const unsigned char *) name, len - 1);
282 head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
283 if (mutex_lock_interruptible(&tomoyo_policy_lock))
284 return NULL;
285 list_for_each_entry(ptr, head, list) {
286 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
287 continue;
288 atomic_inc(&ptr->users);
289 goto out;
290 }
291 ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
292 allocated_len = ptr ? ksize(ptr) : 0;
293 if (!ptr || (tomoyo_quota_for_policy &&
294 atomic_read(&tomoyo_policy_memory_size) + allocated_len
295 > tomoyo_quota_for_policy)) {
296 kfree(ptr);
297 printk(KERN_WARNING "ERROR: Out of memory "
298 "for tomoyo_get_name().\n");
299 if (!tomoyo_policy_loaded)
300 panic("MAC Initialization failed.\n");
301 ptr = NULL;
302 goto out;
303 }
304 atomic_add(allocated_len, &tomoyo_policy_memory_size);
305 ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
306 memmove((char *) ptr->entry.name, name, len);
307 atomic_set(&ptr->users, 1);
308 tomoyo_fill_path_info(&ptr->entry);
309 list_add_tail(&ptr->list, head);
310 out:
311 mutex_unlock(&tomoyo_policy_lock);
312 return ptr ? &ptr->entry : NULL;
313}
314
315/**
316 * tomoyo_realpath_init - Initialize realpath related code.
317 */
318void __init tomoyo_realpath_init(void)
319{
320 int i;
321
322 BUILD_BUG_ON(TOMOYO_MAX_PATHNAME_LEN > PATH_MAX);
323 for (i = 0; i < TOMOYO_MAX_HASH; i++)
324 INIT_LIST_HEAD(&tomoyo_name_list[i]);
325 INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
326 tomoyo_kernel_domain.domainname = tomoyo_get_name(TOMOYO_ROOT_NAME);
327 /*
328 * tomoyo_read_lock() is not needed because this function is
329 * called before the first "delete" request.
330 */
331 list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
332 if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain)
333 panic("Can't register tomoyo_kernel_domain");
334}
335
336/**
337 * tomoyo_read_memory_counter - Check for memory usage in bytes.
338 *
339 * @head: Pointer to "struct tomoyo_io_buffer".
340 *
341 * Returns memory usage.
342 */
343int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head)
344{
345 if (!head->read_eof) {
346 const unsigned int policy
347 = atomic_read(&tomoyo_policy_memory_size);
348 char buffer[64];
349
350 memset(buffer, 0, sizeof(buffer));
351 if (tomoyo_quota_for_policy)
352 snprintf(buffer, sizeof(buffer) - 1,
353 " (Quota: %10u)",
354 tomoyo_quota_for_policy);
355 else
356 buffer[0] = '\0';
357 tomoyo_io_printf(head, "Policy: %10u%s\n", policy, buffer);
358 tomoyo_io_printf(head, "Total: %10u\n", policy);
359 head->read_eof = true;
360 }
361 return 0;
362}
363
364/**
365 * tomoyo_write_memory_quota - Set memory quota.
366 *
367 * @head: Pointer to "struct tomoyo_io_buffer".
368 *
369 * Returns 0.
370 */
371int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head)
372{
373 char *data = head->write_buf;
374 unsigned int size;
375
376 if (sscanf(data, "Policy: %u", &size) == 1)
377 tomoyo_quota_for_policy = size;
378 return 0;
379}
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