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 = &param->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}
202