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c3ef1500 TH |
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 | /* 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 | */ | |
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 | */ | |
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 | */ | |
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_name_list is used for holding string data used by TOMOYO. | |
94 | * Since same string data is likely used for multiple times (e.g. | |
95 | * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of | |
96 | * "const struct tomoyo_path_info *". | |
97 | */ | |
98 | struct list_head tomoyo_name_list[TOMOYO_MAX_HASH]; | |
99 | ||
100 | /** | |
101 | * tomoyo_get_name - Allocate permanent memory for string data. | |
102 | * | |
103 | * @name: The string to store into the permernent memory. | |
104 | * | |
105 | * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise. | |
106 | */ | |
107 | const struct tomoyo_path_info *tomoyo_get_name(const char *name) | |
108 | { | |
109 | struct tomoyo_name_entry *ptr; | |
110 | unsigned int hash; | |
111 | int len; | |
112 | int allocated_len; | |
113 | struct list_head *head; | |
114 | ||
115 | if (!name) | |
116 | return NULL; | |
117 | len = strlen(name) + 1; | |
118 | hash = full_name_hash((const unsigned char *) name, len - 1); | |
119 | head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)]; | |
120 | if (mutex_lock_interruptible(&tomoyo_policy_lock)) | |
121 | return NULL; | |
122 | list_for_each_entry(ptr, head, list) { | |
123 | if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name)) | |
124 | continue; | |
125 | atomic_inc(&ptr->users); | |
126 | goto out; | |
127 | } | |
128 | ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS); | |
129 | allocated_len = ptr ? ksize(ptr) : 0; | |
130 | if (!ptr || (tomoyo_quota_for_policy && | |
131 | atomic_read(&tomoyo_policy_memory_size) + allocated_len | |
132 | > tomoyo_quota_for_policy)) { | |
133 | kfree(ptr); | |
134 | ptr = NULL; | |
135 | tomoyo_warn_oom(__func__); | |
136 | goto out; | |
137 | } | |
138 | atomic_add(allocated_len, &tomoyo_policy_memory_size); | |
139 | ptr->entry.name = ((char *) ptr) + sizeof(*ptr); | |
140 | memmove((char *) ptr->entry.name, name, len); | |
141 | atomic_set(&ptr->users, 1); | |
142 | tomoyo_fill_path_info(&ptr->entry); | |
143 | list_add_tail(&ptr->list, head); | |
144 | out: | |
145 | mutex_unlock(&tomoyo_policy_lock); | |
146 | return ptr ? &ptr->entry : NULL; | |
147 | } | |
148 | ||
149 | /** | |
150 | * tomoyo_mm_init - Initialize mm related code. | |
151 | */ | |
152 | void __init tomoyo_mm_init(void) | |
153 | { | |
154 | int idx; | |
155 | ||
c3ef1500 TH |
156 | for (idx = 0; idx < TOMOYO_MAX_HASH; idx++) |
157 | INIT_LIST_HEAD(&tomoyo_name_list[idx]); | |
158 | INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list); | |
159 | tomoyo_kernel_domain.domainname = tomoyo_get_name(TOMOYO_ROOT_NAME); | |
160 | list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list); | |
161 | idx = tomoyo_read_lock(); | |
162 | if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain) | |
163 | panic("Can't register tomoyo_kernel_domain"); | |
164 | { | |
165 | /* Load built-in policy. */ | |
166 | tomoyo_write_domain_initializer_policy("/sbin/hotplug", | |
167 | false, false); | |
168 | tomoyo_write_domain_initializer_policy("/sbin/modprobe", | |
169 | false, false); | |
170 | } | |
171 | tomoyo_read_unlock(idx); | |
172 | } | |
173 | ||
174 | ||
175 | /* Memory allocated for query lists. */ | |
176 | unsigned int tomoyo_query_memory_size; | |
177 | /* Quota for holding query lists. */ | |
178 | unsigned int tomoyo_quota_for_query; | |
179 | ||
180 | /** | |
181 | * tomoyo_read_memory_counter - Check for memory usage in bytes. | |
182 | * | |
183 | * @head: Pointer to "struct tomoyo_io_buffer". | |
184 | * | |
185 | * Returns memory usage. | |
186 | */ | |
8fbe71f0 | 187 | void tomoyo_read_memory_counter(struct tomoyo_io_buffer *head) |
c3ef1500 TH |
188 | { |
189 | if (!head->read_eof) { | |
190 | const unsigned int policy | |
191 | = atomic_read(&tomoyo_policy_memory_size); | |
192 | const unsigned int query = tomoyo_query_memory_size; | |
193 | char buffer[64]; | |
194 | ||
195 | memset(buffer, 0, sizeof(buffer)); | |
196 | if (tomoyo_quota_for_policy) | |
197 | snprintf(buffer, sizeof(buffer) - 1, | |
198 | " (Quota: %10u)", | |
199 | tomoyo_quota_for_policy); | |
200 | else | |
201 | buffer[0] = '\0'; | |
202 | tomoyo_io_printf(head, "Policy: %10u%s\n", policy, | |
203 | buffer); | |
204 | if (tomoyo_quota_for_query) | |
205 | snprintf(buffer, sizeof(buffer) - 1, | |
206 | " (Quota: %10u)", | |
207 | tomoyo_quota_for_query); | |
208 | else | |
209 | buffer[0] = '\0'; | |
210 | tomoyo_io_printf(head, "Query lists: %10u%s\n", query, | |
211 | buffer); | |
212 | tomoyo_io_printf(head, "Total: %10u\n", policy + query); | |
213 | head->read_eof = true; | |
214 | } | |
c3ef1500 TH |
215 | } |
216 | ||
217 | /** | |
218 | * tomoyo_write_memory_quota - Set memory quota. | |
219 | * | |
220 | * @head: Pointer to "struct tomoyo_io_buffer". | |
221 | * | |
222 | * Returns 0. | |
223 | */ | |
224 | int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head) | |
225 | { | |
226 | char *data = head->write_buf; | |
227 | unsigned int size; | |
228 | ||
229 | if (sscanf(data, "Policy: %u", &size) == 1) | |
230 | tomoyo_quota_for_policy = size; | |
231 | else if (sscanf(data, "Query lists: %u", &size) == 1) | |
232 | tomoyo_quota_for_query = size; | |
233 | return 0; | |
234 | } |