1 /*
2 * security/tomoyo/memory.c
3 *
4 * Memory management functions for TOMOYO.
5 *
6 * Copyright (C) 2005-2010 NTT DATA CORPORATION
7 */
8
9 #include <linux/hash.h>
10 #include <linux/slab.h>
11 #include "common.h"
12
13 /**
14 * tomoyo_warn_oom - Print out of memory warning message.
15 *
16 * @function: Function's name.
17 */
tomoyo_warn_oom(const char * function)18 void tomoyo_warn_oom(const char *function)
19 {
20 /* Reduce error messages. */
21 static pid_t tomoyo_last_pid;
22 const pid_t pid = current->pid;
23 if (tomoyo_last_pid != pid) {
24 printk(KERN_WARNING "ERROR: Out of memory at %s.\n",
25 function);
26 tomoyo_last_pid = pid;
27 }
28 if (!tomoyo_policy_loaded)
29 panic("MAC Initialization failed.\n");
30 }
31
32 /* Memory allocated for policy. */
33 static atomic_t tomoyo_policy_memory_size;
34 /* Quota for holding policy. */
35 static unsigned int tomoyo_quota_for_policy;
36
37 /**
38 * tomoyo_memory_ok - Check memory quota.
39 *
40 * @ptr: Pointer to allocated memory.
41 *
42 * Returns true on success, false otherwise.
43 *
44 * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
45 */
tomoyo_memory_ok(void * ptr)46 bool tomoyo_memory_ok(void *ptr)
47 {
48 size_t s = ptr ? ksize(ptr) : 0;
49 atomic_add(s, &tomoyo_policy_memory_size);
50 if (ptr && (!tomoyo_quota_for_policy ||
51 atomic_read(&tomoyo_policy_memory_size)
52 <= tomoyo_quota_for_policy)) {
53 memset(ptr, 0, s);
54 return true;
55 }
56 atomic_sub(s, &tomoyo_policy_memory_size);
57 tomoyo_warn_oom(__func__);
58 return false;
59 }
60
61 /**
62 * tomoyo_commit_ok - Check memory quota.
63 *
64 * @data: Data to copy from.
65 * @size: Size in byte.
66 *
67 * Returns pointer to allocated memory on success, NULL otherwise.
68 * @data is zero-cleared on success.
69 */
tomoyo_commit_ok(void * data,const unsigned int size)70 void *tomoyo_commit_ok(void *data, const unsigned int size)
71 {
72 void *ptr = kzalloc(size, GFP_NOFS);
73 if (tomoyo_memory_ok(ptr)) {
74 memmove(ptr, data, size);
75 memset(data, 0, size);
76 return ptr;
77 }
78 return NULL;
79 }
80
81 /**
82 * tomoyo_memory_free - Free memory for elements.
83 *
84 * @ptr: Pointer to allocated memory.
85 */
tomoyo_memory_free(void * ptr)86 void tomoyo_memory_free(void *ptr)
87 {
88 atomic_sub(ksize(ptr), &tomoyo_policy_memory_size);
89 kfree(ptr);
90 }
91
92 /**
93 * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
94 *
95 * @group_name: The name of address group.
96 * @idx: Index number.
97 *
98 * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
99 */
tomoyo_get_group(const char * group_name,const u8 idx)100 struct tomoyo_group *tomoyo_get_group(const char *group_name, const u8 idx)
101 {
102 struct tomoyo_group e = { };
103 struct tomoyo_group *group = NULL;
104 bool found = false;
105 if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
106 return NULL;
107 e.group_name = tomoyo_get_name(group_name);
108 if (!e.group_name)
109 return NULL;
110 if (mutex_lock_interruptible(&tomoyo_policy_lock))
111 goto out;
112 list_for_each_entry(group, &tomoyo_group_list[idx], list) {
113 if (e.group_name != group->group_name)
114 continue;
115 atomic_inc(&group->users);
116 found = true;
117 break;
118 }
119 if (!found) {
120 struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
121 if (entry) {
122 INIT_LIST_HEAD(&entry->member_list);
123 atomic_set(&entry->users, 1);
124 list_add_tail_rcu(&entry->list,
125 &tomoyo_group_list[idx]);
126 group = entry;
127 found = true;
128 }
129 }
130 mutex_unlock(&tomoyo_policy_lock);
131 out:
132 tomoyo_put_name(e.group_name);
133 return found ? group : NULL;
134 }
135
136 /*
137 * tomoyo_name_list is used for holding string data used by TOMOYO.
138 * Since same string data is likely used for multiple times (e.g.
139 * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
140 * "const struct tomoyo_path_info *".
141 */
142 struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
143
144 /**
145 * tomoyo_get_name - Allocate permanent memory for string data.
146 *
147 * @name: The string to store into the permernent memory.
148 *
149 * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
150 */
tomoyo_get_name(const char * name)151 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
152 {
153 struct tomoyo_name *ptr;
154 unsigned int hash;
155 int len;
156 int allocated_len;
157 struct list_head *head;
158
159 if (!name)
160 return NULL;
161 len = strlen(name) + 1;
162 hash = full_name_hash((const unsigned char *) name, len - 1);
163 head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
164 if (mutex_lock_interruptible(&tomoyo_policy_lock))
165 return NULL;
166 list_for_each_entry(ptr, head, list) {
167 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
168 continue;
169 atomic_inc(&ptr->users);
170 goto out;
171 }
172 ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
173 allocated_len = ptr ? ksize(ptr) : 0;
174 if (!ptr || (tomoyo_quota_for_policy &&
175 atomic_read(&tomoyo_policy_memory_size) + allocated_len
176 > tomoyo_quota_for_policy)) {
177 kfree(ptr);
178 ptr = NULL;
179 tomoyo_warn_oom(__func__);
180 goto out;
181 }
182 atomic_add(allocated_len, &tomoyo_policy_memory_size);
183 ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
184 memmove((char *) ptr->entry.name, name, len);
185 atomic_set(&ptr->users, 1);
186 tomoyo_fill_path_info(&ptr->entry);
187 list_add_tail(&ptr->list, head);
188 out:
189 mutex_unlock(&tomoyo_policy_lock);
190 return ptr ? &ptr->entry : NULL;
191 }
192
193 /**
194 * tomoyo_mm_init - Initialize mm related code.
195 */
tomoyo_mm_init(void)196 void __init tomoyo_mm_init(void)
197 {
198 int idx;
199
200 for (idx = 0; idx < TOMOYO_MAX_POLICY; idx++)
201 INIT_LIST_HEAD(&tomoyo_policy_list[idx]);
202 for (idx = 0; idx < TOMOYO_MAX_GROUP; idx++)
203 INIT_LIST_HEAD(&tomoyo_group_list[idx]);
204 for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
205 INIT_LIST_HEAD(&tomoyo_name_list[idx]);
206 INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
207 tomoyo_kernel_domain.domainname = tomoyo_get_name(TOMOYO_ROOT_NAME);
208 list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
209 idx = tomoyo_read_lock();
210 if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain)
211 panic("Can't register tomoyo_kernel_domain");
212 {
213 /* Load built-in policy. */
214 tomoyo_write_transition_control("/sbin/hotplug", false,
215 TOMOYO_TRANSITION_CONTROL_INITIALIZE);
216 tomoyo_write_transition_control("/sbin/modprobe", false,
217 TOMOYO_TRANSITION_CONTROL_INITIALIZE);
218 }
219 tomoyo_read_unlock(idx);
220 }
221
222
223 /* Memory allocated for query lists. */
224 unsigned int tomoyo_query_memory_size;
225 /* Quota for holding query lists. */
226 unsigned int tomoyo_quota_for_query;
227
228 /**
229 * tomoyo_read_memory_counter - Check for memory usage in bytes.
230 *
231 * @head: Pointer to "struct tomoyo_io_buffer".
232 *
233 * Returns memory usage.
234 */
tomoyo_read_memory_counter(struct tomoyo_io_buffer * head)235 void tomoyo_read_memory_counter(struct tomoyo_io_buffer *head)
236 {
237 if (!head->r.eof) {
238 const unsigned int policy
239 = atomic_read(&tomoyo_policy_memory_size);
240 const unsigned int query = tomoyo_query_memory_size;
241 char buffer[64];
242
243 memset(buffer, 0, sizeof(buffer));
244 if (tomoyo_quota_for_policy)
245 snprintf(buffer, sizeof(buffer) - 1,
246 " (Quota: %10u)",
247 tomoyo_quota_for_policy);
248 else
249 buffer[0] = '\0';
250 tomoyo_io_printf(head, "Policy: %10u%s\n", policy,
251 buffer);
252 if (tomoyo_quota_for_query)
253 snprintf(buffer, sizeof(buffer) - 1,
254 " (Quota: %10u)",
255 tomoyo_quota_for_query);
256 else
257 buffer[0] = '\0';
258 tomoyo_io_printf(head, "Query lists: %10u%s\n", query,
259 buffer);
260 tomoyo_io_printf(head, "Total: %10u\n", policy + query);
261 head->r.eof = true;
262 }
263 }
264
265 /**
266 * tomoyo_write_memory_quota - Set memory quota.
267 *
268 * @head: Pointer to "struct tomoyo_io_buffer".
269 *
270 * Returns 0.
271 */
tomoyo_write_memory_quota(struct tomoyo_io_buffer * head)272 int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head)
273 {
274 char *data = head->write_buf;
275 unsigned int size;
276
277 if (sscanf(data, "Policy: %u", &size) == 1)
278 tomoyo_quota_for_policy = size;
279 else if (sscanf(data, "Query lists: %u", &size) == 1)
280 tomoyo_quota_for_query = size;
281 return 0;
282 }
283