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1/*
2 * security/tomoyo/memory.c
3 *
4 * Copyright (C) 2005-2011 NTT DATA CORPORATION
5 */
6
7#include <linux/hash.h>
8#include <linux/slab.h>
9#include "common.h"
10
11/**
12 * tomoyo_warn_oom - Print out of memory warning message.
13 *
14 * @function: Function's name.
15 */
16void tomoyo_warn_oom(const char *function)
17{
18 /* Reduce error messages. */
19 static pid_t tomoyo_last_pid;
20 const pid_t pid = current->pid;
21 if (tomoyo_last_pid != pid) {
22 printk(KERN_WARNING "ERROR: Out of memory at %s.\n",
23 function);
24 tomoyo_last_pid = pid;
25 }
26 if (!tomoyo_policy_loaded)
27 panic("MAC Initialization failed.\n");
28}
29
30/* Memoy currently used by policy/audit log/query. */
31unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
32/* Memory quota for "policy"/"audit log"/"query". */
33unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT];
34
35/**
36 * tomoyo_memory_ok - Check memory quota.
37 *
38 * @ptr: Pointer to allocated memory.
39 *
40 * Returns true on success, false otherwise.
41 *
42 * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
43 *
44 * Caller holds tomoyo_policy_lock mutex.
45 */
46bool tomoyo_memory_ok(void *ptr)
47{
48 if (ptr) {
49 const size_t s = ksize(ptr);
50 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
51 if (!tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
52 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
53 tomoyo_memory_quota[TOMOYO_MEMORY_POLICY])
54 return true;
55 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
56 }
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 *
70 * Caller holds tomoyo_policy_lock mutex.
71 */
72void *tomoyo_commit_ok(void *data, const unsigned int size)
73{
74 void *ptr = kzalloc(size, GFP_NOFS);
75 if (tomoyo_memory_ok(ptr)) {
76 memmove(ptr, data, size);
77 memset(data, 0, size);
78 return ptr;
79 }
80 kfree(ptr);
81 return NULL;
82}
83
84/**
85 * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
86 *
87 * @param: Pointer to "struct tomoyo_acl_param".
88 * @idx: Index number.
89 *
90 * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
91 */
92struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
93 const u8 idx)
94{
95 struct tomoyo_group e = { };
96 struct tomoyo_group *group = NULL;
97 struct list_head *list;
98 const char *group_name = tomoyo_read_token(param);
99 bool found = false;
100 if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
101 return NULL;
102 e.group_name = tomoyo_get_name(group_name);
103 if (!e.group_name)
104 return NULL;
105 if (mutex_lock_interruptible(&tomoyo_policy_lock))
106 goto out;
107 list = ¶m->ns->group_list[idx];
108 list_for_each_entry(group, list, head.list) {
109 if (e.group_name != group->group_name ||
110 atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS)
111 continue;
112 atomic_inc(&group->head.users);
113 found = true;
114 break;
115 }
116 if (!found) {
117 struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
118 if (entry) {
119 INIT_LIST_HEAD(&entry->member_list);
120 atomic_set(&entry->head.users, 1);
121 list_add_tail_rcu(&entry->head.list, list);
122 group = entry;
123 found = true;
124 }
125 }
126 mutex_unlock(&tomoyo_policy_lock);
127out:
128 tomoyo_put_name(e.group_name);
129 return found ? group : NULL;
130}
131
132/*
133 * tomoyo_name_list is used for holding string data used by TOMOYO.
134 * Since same string data is likely used for multiple times (e.g.
135 * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
136 * "const struct tomoyo_path_info *".
137 */
138struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
139
140/**
141 * tomoyo_get_name - Allocate permanent memory for string data.
142 *
143 * @name: The string to store into the permernent memory.
144 *
145 * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
146 */
147const struct tomoyo_path_info *tomoyo_get_name(const char *name)
148{
149 struct tomoyo_name *ptr;
150 unsigned int hash;
151 int len;
152 struct list_head *head;
153
154 if (!name)
155 return NULL;
156 len = strlen(name) + 1;
157 hash = full_name_hash((const unsigned char *) name, len - 1);
158 head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
159 if (mutex_lock_interruptible(&tomoyo_policy_lock))
160 return NULL;
161 list_for_each_entry(ptr, head, head.list) {
162 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) ||
163 atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
164 continue;
165 atomic_inc(&ptr->head.users);
166 goto out;
167 }
168 ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
169 if (tomoyo_memory_ok(ptr)) {
170 ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
171 memmove((char *) ptr->entry.name, name, len);
172 atomic_set(&ptr->head.users, 1);
173 tomoyo_fill_path_info(&ptr->entry);
174 list_add_tail(&ptr->head.list, head);
175 } else {
176 kfree(ptr);
177 ptr = NULL;
178 }
179out:
180 mutex_unlock(&tomoyo_policy_lock);
181 return ptr ? &ptr->entry : NULL;
182}
183
184/* Initial namespace.*/
185struct tomoyo_policy_namespace tomoyo_kernel_namespace;
186
187/**
188 * tomoyo_mm_init - Initialize mm related code.
189 */
190void __init tomoyo_mm_init(void)
191{
192 int idx;
193 for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
194 INIT_LIST_HEAD(&tomoyo_name_list[idx]);
195 tomoyo_kernel_namespace.name = "<kernel>";
196 tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
197 tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
198 INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
199 tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
200 list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
201}