78b6143068de2cb1031b3020bd4c2488deebe9b3
[linux-2.6.git] / security / tomoyo / memory.c
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  */
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 /* Lock for protecting tomoyo_memory_used. */
33 static DEFINE_SPINLOCK(tomoyo_policy_memory_lock);
34 /* Memoy currently used by policy/audit log/query. */
35 unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
36 /* Memory quota for "policy"/"audit log"/"query". */
37 unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT];
38
39 /**
40  * tomoyo_memory_ok - Check memory quota.
41  *
42  * @ptr: Pointer to allocated memory.
43  *
44  * Returns true on success, false otherwise.
45  *
46  * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
47  */
48 bool tomoyo_memory_ok(void *ptr)
49 {
50         if (ptr) {
51                 const size_t s = ksize(ptr);
52                 bool result;
53                 spin_lock(&tomoyo_policy_memory_lock);
54                 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
55                 result = !tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
56                         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
57                         tomoyo_memory_quota[TOMOYO_MEMORY_POLICY];
58                 if (!result)
59                         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
60                 spin_unlock(&tomoyo_policy_memory_lock);
61                 if (result)
62                         return true;
63         }
64         tomoyo_warn_oom(__func__);
65         return false;
66 }
67
68 /**
69  * tomoyo_commit_ok - Check memory quota.
70  *
71  * @data:   Data to copy from.
72  * @size:   Size in byte.
73  *
74  * Returns pointer to allocated memory on success, NULL otherwise.
75  * @data is zero-cleared on success.
76  */
77 void *tomoyo_commit_ok(void *data, const unsigned int size)
78 {
79         void *ptr = kzalloc(size, GFP_NOFS);
80         if (tomoyo_memory_ok(ptr)) {
81                 memmove(ptr, data, size);
82                 memset(data, 0, size);
83                 return ptr;
84         }
85         kfree(ptr);
86         return NULL;
87 }
88
89 /**
90  * tomoyo_memory_free - Free memory for elements.
91  *
92  * @ptr:  Pointer to allocated memory.
93  */
94 void tomoyo_memory_free(void *ptr)
95 {
96         size_t s = ksize(ptr);
97         spin_lock(&tomoyo_policy_memory_lock);
98         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
99         spin_unlock(&tomoyo_policy_memory_lock);
100         kfree(ptr);
101 }
102
103 /**
104  * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
105  *
106  * @param: Pointer to "struct tomoyo_acl_param".
107  * @idx:   Index number.
108  *
109  * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
110  */
111 struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
112                                       const u8 idx)
113 {
114         struct tomoyo_group e = { };
115         struct tomoyo_group *group = NULL;
116         struct list_head *list;
117         const char *group_name = tomoyo_read_token(param);
118         bool found = false;
119         if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
120                 return NULL;
121         e.group_name = tomoyo_get_name(group_name);
122         if (!e.group_name)
123                 return NULL;
124         if (mutex_lock_interruptible(&tomoyo_policy_lock))
125                 goto out;
126         list = &param->ns->group_list[idx];
127         list_for_each_entry(group, list, head.list) {
128                 if (e.group_name != group->group_name)
129                         continue;
130                 atomic_inc(&group->head.users);
131                 found = true;
132                 break;
133         }
134         if (!found) {
135                 struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
136                 if (entry) {
137                         INIT_LIST_HEAD(&entry->member_list);
138                         atomic_set(&entry->head.users, 1);
139                         list_add_tail_rcu(&entry->head.list, list);
140                         group = entry;
141                         found = true;
142                 }
143         }
144         mutex_unlock(&tomoyo_policy_lock);
145 out:
146         tomoyo_put_name(e.group_name);
147         return found ? group : NULL;
148 }
149
150 /*
151  * tomoyo_name_list is used for holding string data used by TOMOYO.
152  * Since same string data is likely used for multiple times (e.g.
153  * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
154  * "const struct tomoyo_path_info *".
155  */
156 struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
157
158 /**
159  * tomoyo_get_name - Allocate permanent memory for string data.
160  *
161  * @name: The string to store into the permernent memory.
162  *
163  * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
164  */
165 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
166 {
167         struct tomoyo_name *ptr;
168         unsigned int hash;
169         int len;
170         struct list_head *head;
171
172         if (!name)
173                 return NULL;
174         len = strlen(name) + 1;
175         hash = full_name_hash((const unsigned char *) name, len - 1);
176         head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
177         if (mutex_lock_interruptible(&tomoyo_policy_lock))
178                 return NULL;
179         list_for_each_entry(ptr, head, head.list) {
180                 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
181                         continue;
182                 atomic_inc(&ptr->head.users);
183                 goto out;
184         }
185         ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
186         if (tomoyo_memory_ok(ptr)) {
187                 ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
188                 memmove((char *) ptr->entry.name, name, len);
189                 atomic_set(&ptr->head.users, 1);
190                 tomoyo_fill_path_info(&ptr->entry);
191                 list_add_tail(&ptr->head.list, head);
192         } else {
193                 kfree(ptr);
194                 ptr = NULL;
195         }
196 out:
197         mutex_unlock(&tomoyo_policy_lock);
198         return ptr ? &ptr->entry : NULL;
199 }
200
201 /* Initial namespace.*/
202 struct tomoyo_policy_namespace tomoyo_kernel_namespace;
203
204 /**
205  * tomoyo_mm_init - Initialize mm related code.
206  */
207 void __init tomoyo_mm_init(void)
208 {
209         int idx;
210         for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
211                 INIT_LIST_HEAD(&tomoyo_name_list[idx]);
212         tomoyo_kernel_namespace.name = "<kernel>";
213         tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
214         tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
215         INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
216         tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
217         list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
218 #if 0
219         /* Will be replaced with tomoyo_load_builtin_policy(). */
220         {
221                 /* Load built-in policy. */
222                 tomoyo_write_transition_control("/sbin/hotplug", false,
223                                         TOMOYO_TRANSITION_CONTROL_INITIALIZE);
224                 tomoyo_write_transition_control("/sbin/modprobe", false,
225                                         TOMOYO_TRANSITION_CONTROL_INITIALIZE);
226         }
227 #endif
228 }