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

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