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 /* 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 }