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  */
tomoyo_warn_oom(const char * function)16 void 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. */
31 unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
32 /* Memory quota for "policy"/"audit log"/"query". */
33 unsigned 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  */
tomoyo_memory_ok(void * ptr)46 bool 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  */
tomoyo_commit_ok(void * data,const unsigned int size)72 void *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  */
tomoyo_get_group(struct tomoyo_acl_param * param,const u8 idx)92 struct 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);
127 out:
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  */
138 struct 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  */
tomoyo_get_name(const char * name)147 const 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 	}
179 out:
180 	mutex_unlock(&tomoyo_policy_lock);
181 	return ptr ? &ptr->entry : NULL;
182 }
183 
184 /* Initial namespace.*/
185 struct tomoyo_policy_namespace tomoyo_kernel_namespace;
186 
187 /**
188  * tomoyo_mm_init - Initialize mm related code.
189  */
tomoyo_mm_init(void)190 void __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