security/tomoyo/memory.c

   1 /*
   2  * security/tomoyo/memory.c
   3  *
   4  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   5  */
   6
   7 #include <linux/hash.h>
   8 #include <linux/slab.h>
   9 #include "common.h"
  10
  11 /**
  12  * tomoyo_warn_oom - Print out of memory warning message.
  13  *
  14  * @function: Function's name.
  15  */
  16 void tomoyo_warn_oom(const char *function)
  17 {
  18         /* Reduce error messages. */
  19         static pid_t tomoyo_last_pid;
  20         const pid_t pid = current->pid;
  21         if (tomoyo_last_pid != pid) {
  22                 printk(KERN_WARNING "ERROR: Out of memory at %s.\n",
  23                        function);
  24                 tomoyo_last_pid = pid;
  25         }
  26         if (!tomoyo_policy_loaded)
  27                 panic("MAC Initialization failed.\n");
  28 }
  29
  30 /* Lock for protecting tomoyo_memory_used. */
  31 static DEFINE_SPINLOCK(tomoyo_policy_memory_lock);
  32 /* Memoy currently used by policy/audit log/query. */
  33 unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
  34 /* Memory quota for "policy"/"audit log"/"query". */
  35 unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT];
  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         if (ptr) {
  49                 const size_t s = ksize(ptr);
  50                 bool result;
  51                 spin_lock(&tomoyo_policy_memory_lock);
  52                 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
  53                 result = !tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
  54                         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
  55                         tomoyo_memory_quota[TOMOYO_MEMORY_POLICY];
  56                 if (!result)
  57                         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
  58                 spin_unlock(&tomoyo_policy_memory_lock);
  59                 if (result)
  60                         return true;
  61         }
  62         tomoyo_warn_oom(__func__);
  63         return false;
  64 }
  65
  66 /**
  67  * tomoyo_commit_ok - Check memory quota.
  68  *
  69  * @data:   Data to copy from.
  70  * @size:   Size in byte.
  71  *
  72  * Returns pointer to allocated memory on success, NULL otherwise.
  73  * @data is zero-cleared on success.
  74  */
  75 void *tomoyo_commit_ok(void *data, const unsigned int size)
  76 {
  77         void *ptr = kzalloc(size, GFP_NOFS);
  78         if (tomoyo_memory_ok(ptr)) {
  79                 memmove(ptr, data, size);
  80                 memset(data, 0, size);
  81                 return ptr;
  82         }
  83         kfree(ptr);
  84         return NULL;
  85 }
  86
  87 /**
  88  * tomoyo_memory_free - Free memory for elements.
  89  *
  90  * @ptr:  Pointer to allocated memory.
  91  */
  92 void tomoyo_memory_free(void *ptr)
  93 {
  94         size_t s = ksize(ptr);
  95         spin_lock(&tomoyo_policy_memory_lock);
  96         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
  97         spin_unlock(&tomoyo_policy_memory_lock);
  98         kfree(ptr);
  99 }
 100
 101 /**
 102  * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
 103  *
 104  * @param: Pointer to "struct tomoyo_acl_param".
 105  * @idx:   Index number.
 106  *
 107  * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
 108  */
 109 struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
 110                                       const u8 idx)
 111 {
 112         struct tomoyo_group e = { };
 113         struct tomoyo_group *group = NULL;
 114         struct list_head *list;
 115         const char *group_name = tomoyo_read_token(param);
 116         bool found = false;
 117         if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
 118                 return NULL;
 119         e.group_name = tomoyo_get_name(group_name);
 120         if (!e.group_name)
 121                 return NULL;
 122         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 123                 goto out;
 124         list = &param->ns->group_list[idx];
 125         list_for_each_entry(group, list, head.list) {
 126                 if (e.group_name != group->group_name)
 127                         continue;
 128                 atomic_inc(&group->head.users);
 129                 found = true;
 130                 break;
 131         }
 132         if (!found) {
 133                 struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
 134                 if (entry) {
 135                         INIT_LIST_HEAD(&entry->member_list);
 136                         atomic_set(&entry->head.users, 1);
 137                         list_add_tail_rcu(&entry->head.list, list);
 138                         group = entry;
 139                         found = true;
 140                 }
 141         }
 142         mutex_unlock(&tomoyo_policy_lock);
 143 out:
 144         tomoyo_put_name(e.group_name);
 145         return found ? group : NULL;
 146 }
 147
 148 /*
 149  * tomoyo_name_list is used for holding string data used by TOMOYO.
 150  * Since same string data is likely used for multiple times (e.g.
 151  * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
 152  * "const struct tomoyo_path_info *".
 153  */
 154 struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
 155
 156 /**
 157  * tomoyo_get_name - Allocate permanent memory for string data.
 158  *
 159  * @name: The string to store into the permernent memory.
 160  *
 161  * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
 162  */
 163 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
 164 {
 165         struct tomoyo_name *ptr;
 166         unsigned int hash;
 167         int len;
 168         struct list_head *head;
 169
 170         if (!name)
 171                 return NULL;
 172         len = strlen(name) + 1;
 173         hash = full_name_hash((const unsigned char *) name, len - 1);
 174         head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
 175         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 176                 return NULL;
 177         list_for_each_entry(ptr, head, head.list) {
 178                 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
 179                         continue;
 180                 atomic_inc(&ptr->head.users);
 181                 goto out;
 182         }
 183         ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
 184         if (tomoyo_memory_ok(ptr)) {
 185                 ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
 186                 memmove((char *) ptr->entry.name, name, len);
 187                 atomic_set(&ptr->head.users, 1);
 188                 tomoyo_fill_path_info(&ptr->entry);
 189                 list_add_tail(&ptr->head.list, head);
 190         } else {
 191                 kfree(ptr);
 192                 ptr = NULL;
 193         }
 194 out:
 195         mutex_unlock(&tomoyo_policy_lock);
 196         return ptr ? &ptr->entry : NULL;
 197 }
 198
 199 /* Initial namespace.*/
 200 struct tomoyo_policy_namespace tomoyo_kernel_namespace;
 201
 202 /**
 203  * tomoyo_mm_init - Initialize mm related code.
 204  */
 205 void __init tomoyo_mm_init(void)
 206 {
 207         int idx;
 208         for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
 209                 INIT_LIST_HEAD(&tomoyo_name_list[idx]);
 210         tomoyo_kernel_namespace.name = "<kernel>";
 211         tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
 212         tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
 213         INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
 214         tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
 215         list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
 216 }