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TOMOYO Linux Cross Reference
Linux/security/tomoyo/memory.c

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  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         kfree(ptr);
 79         return NULL;
 80 }
 81 
 82 /**
 83  * tomoyo_memory_free - Free memory for elements.
 84  *
 85  * @ptr:  Pointer to allocated memory.
 86  */
 87 void tomoyo_memory_free(void *ptr)
 88 {
 89         atomic_sub(ksize(ptr), &tomoyo_policy_memory_size);
 90         kfree(ptr);
 91 }
 92 
 93 /**
 94  * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
 95  *
 96  * @group_name: The name of address group.
 97  * @idx:        Index number.
 98  *
 99  * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
100  */
101 struct tomoyo_group *tomoyo_get_group(const char *group_name, const u8 idx)
102 {
103         struct tomoyo_group e = { };
104         struct tomoyo_group *group = NULL;
105         bool found = false;
106         if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
107                 return NULL;
108         e.group_name = tomoyo_get_name(group_name);
109         if (!e.group_name)
110                 return NULL;
111         if (mutex_lock_interruptible(&tomoyo_policy_lock))
112                 goto out;
113         list_for_each_entry(group, &tomoyo_group_list[idx], list) {
114                 if (e.group_name != group->group_name)
115                         continue;
116                 atomic_inc(&group->users);
117                 found = true;
118                 break;
119         }
120         if (!found) {
121                 struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
122                 if (entry) {
123                         INIT_LIST_HEAD(&entry->member_list);
124                         atomic_set(&entry->users, 1);
125                         list_add_tail_rcu(&entry->list,
126                                           &tomoyo_group_list[idx]);
127                         group = entry;
128                         found = true;
129                 }
130         }
131         mutex_unlock(&tomoyo_policy_lock);
132  out:
133         tomoyo_put_name(e.group_name);
134         return found ? group : NULL;
135 }
136 
137 /*
138  * tomoyo_name_list is used for holding string data used by TOMOYO.
139  * Since same string data is likely used for multiple times (e.g.
140  * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
141  * "const struct tomoyo_path_info *".
142  */
143 struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
144 
145 /**
146  * tomoyo_get_name - Allocate permanent memory for string data.
147  *
148  * @name: The string to store into the permernent memory.
149  *
150  * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
151  */
152 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
153 {
154         struct tomoyo_name *ptr;
155         unsigned int hash;
156         int len;
157         int allocated_len;
158         struct list_head *head;
159 
160         if (!name)
161                 return NULL;
162         len = strlen(name) + 1;
163         hash = full_name_hash((const unsigned char *) name, len - 1);
164         head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
165         if (mutex_lock_interruptible(&tomoyo_policy_lock))
166                 return NULL;
167         list_for_each_entry(ptr, head, list) {
168                 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
169                         continue;
170                 atomic_inc(&ptr->users);
171                 goto out;
172         }
173         ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
174         allocated_len = ptr ? ksize(ptr) : 0;
175         if (!ptr || (tomoyo_quota_for_policy &&
176                      atomic_read(&tomoyo_policy_memory_size) + allocated_len
177                      > tomoyo_quota_for_policy)) {
178                 kfree(ptr);
179                 ptr = NULL;
180                 tomoyo_warn_oom(__func__);
181                 goto out;
182         }
183         atomic_add(allocated_len, &tomoyo_policy_memory_size);
184         ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
185         memmove((char *) ptr->entry.name, name, len);
186         atomic_set(&ptr->users, 1);
187         tomoyo_fill_path_info(&ptr->entry);
188         list_add_tail(&ptr->list, head);
189  out:
190         mutex_unlock(&tomoyo_policy_lock);
191         return ptr ? &ptr->entry : NULL;
192 }
193 
194 /**
195  * tomoyo_mm_init - Initialize mm related code.
196  */
197 void __init tomoyo_mm_init(void)
198 {
199         int idx;
200 
201         for (idx = 0; idx < TOMOYO_MAX_POLICY; idx++)
202                 INIT_LIST_HEAD(&tomoyo_policy_list[idx]);
203         for (idx = 0; idx < TOMOYO_MAX_GROUP; idx++)
204                 INIT_LIST_HEAD(&tomoyo_group_list[idx]);
205         for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
206                 INIT_LIST_HEAD(&tomoyo_name_list[idx]);
207         INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
208         tomoyo_kernel_domain.domainname = tomoyo_get_name(TOMOYO_ROOT_NAME);
209         list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
210         idx = tomoyo_read_lock();
211         if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain)
212                 panic("Can't register tomoyo_kernel_domain");
213         {
214                 /* Load built-in policy. */
215                 tomoyo_write_transition_control("/sbin/hotplug", false,
216                                         TOMOYO_TRANSITION_CONTROL_INITIALIZE);
217                 tomoyo_write_transition_control("/sbin/modprobe", false,
218                                         TOMOYO_TRANSITION_CONTROL_INITIALIZE);
219         }
220         tomoyo_read_unlock(idx);
221 }
222 
223 
224 /* Memory allocated for query lists. */
225 unsigned int tomoyo_query_memory_size;
226 /* Quota for holding query lists. */
227 unsigned int tomoyo_quota_for_query;
228 
229 /**
230  * tomoyo_read_memory_counter - Check for memory usage in bytes.
231  *
232  * @head: Pointer to "struct tomoyo_io_buffer".
233  *
234  * Returns memory usage.
235  */
236 void tomoyo_read_memory_counter(struct tomoyo_io_buffer *head)
237 {
238         if (!head->r.eof) {
239                 const unsigned int policy
240                         = atomic_read(&tomoyo_policy_memory_size);
241                 const unsigned int query = tomoyo_query_memory_size;
242                 char buffer[64];
243 
244                 memset(buffer, 0, sizeof(buffer));
245                 if (tomoyo_quota_for_policy)
246                         snprintf(buffer, sizeof(buffer) - 1,
247                                  "   (Quota: %10u)",
248                                  tomoyo_quota_for_policy);
249                 else
250                         buffer[0] = '\0';
251                 tomoyo_io_printf(head, "Policy:       %10u%s\n", policy,
252                                  buffer);
253                 if (tomoyo_quota_for_query)
254                         snprintf(buffer, sizeof(buffer) - 1,
255                                  "   (Quota: %10u)",
256                                  tomoyo_quota_for_query);
257                 else
258                         buffer[0] = '\0';
259                 tomoyo_io_printf(head, "Query lists:  %10u%s\n", query,
260                                  buffer);
261                 tomoyo_io_printf(head, "Total:        %10u\n", policy + query);
262                 head->r.eof = true;
263         }
264 }
265 
266 /**
267  * tomoyo_write_memory_quota - Set memory quota.
268  *
269  * @head: Pointer to "struct tomoyo_io_buffer".
270  *
271  * Returns 0.
272  */
273 int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head)
274 {
275         char *data = head->write_buf;
276         unsigned int size;
277 
278         if (sscanf(data, "Policy: %u", &size) == 1)
279                 tomoyo_quota_for_policy = size;
280         else if (sscanf(data, "Query lists: %u", &size) == 1)
281                 tomoyo_quota_for_query = size;
282         return 0;
283 }
284 

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