linux/security/tomoyo/memory.c
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   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 */
  16void 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/* Memoy currently used by policy/audit log/query. */
  31unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
  32/* Memory quota for "policy"/"audit log"/"query". */
  33unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT];
  34
  35/**
  36 * tomoyo_memory_ok - Check memory quota.
  37 *
  38 * @ptr: Pointer to allocated memory.
  39 *
  40 * Returns true on success, false otherwise.
  41 *
  42 * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
  43 *
  44 * Caller holds tomoyo_policy_lock mutex.
  45 */
  46bool tomoyo_memory_ok(void *ptr)
  47{
  48        if (ptr) {
  49                const size_t s = ksize(ptr);
  50                tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
  51                if (!tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
  52                    tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
  53                    tomoyo_memory_quota[TOMOYO_MEMORY_POLICY])
  54                        return true;
  55                tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
  56        }
  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 * Caller holds tomoyo_policy_lock mutex.
  71 */
  72void *tomoyo_commit_ok(void *data, const unsigned int size)
  73{
  74        void *ptr = kzalloc(size, GFP_NOFS);
  75        if (tomoyo_memory_ok(ptr)) {
  76                memmove(ptr, data, size);
  77                memset(data, 0, size);
  78                return ptr;
  79        }
  80        kfree(ptr);
  81        return NULL;
  82}
  83
  84/**
  85 * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
  86 *
  87 * @param: Pointer to "struct tomoyo_acl_param".
  88 * @idx:   Index number.
  89 *
  90 * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
  91 */
  92struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
  93                                      const u8 idx)
  94{
  95        struct tomoyo_group e = { };
  96        struct tomoyo_group *group = NULL;
  97        struct list_head *list;
  98        const char *group_name = tomoyo_read_token(param);
  99        bool found = false;
 100        if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
 101                return NULL;
 102        e.group_name = tomoyo_get_name(group_name);
 103        if (!e.group_name)
 104                return NULL;
 105        if (mutex_lock_interruptible(&tomoyo_policy_lock))
 106                goto out;
 107        list = &param->ns->group_list[idx];
 108        list_for_each_entry(group, list, head.list) {
 109                if (e.group_name != group->group_name ||
 110                    atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS)
 111                        continue;
 112                atomic_inc(&group->head.users);
 113                found = true;
 114                break;
 115        }
 116        if (!found) {
 117                struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
 118                if (entry) {
 119                        INIT_LIST_HEAD(&entry->member_list);
 120                        atomic_set(&entry->head.users, 1);
 121                        list_add_tail_rcu(&entry->head.list, list);
 122                        group = entry;
 123                        found = true;
 124                }
 125        }
 126        mutex_unlock(&tomoyo_policy_lock);
 127out:
 128        tomoyo_put_name(e.group_name);
 129        return found ? group : NULL;
 130}
 131
 132/*
 133 * tomoyo_name_list is used for holding string data used by TOMOYO.
 134 * Since same string data is likely used for multiple times (e.g.
 135 * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
 136 * "const struct tomoyo_path_info *".
 137 */
 138struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
 139
 140/**
 141 * tomoyo_get_name - Allocate permanent memory for string data.
 142 *
 143 * @name: The string to store into the permernent memory.
 144 *
 145 * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
 146 */
 147const struct tomoyo_path_info *tomoyo_get_name(const char *name)
 148{
 149        struct tomoyo_name *ptr;
 150        unsigned int hash;
 151        int len;
 152        struct list_head *head;
 153
 154        if (!name)
 155                return NULL;
 156        len = strlen(name) + 1;
 157        hash = full_name_hash((const unsigned char *) name, len - 1);
 158        head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
 159        if (mutex_lock_interruptible(&tomoyo_policy_lock))
 160                return NULL;
 161        list_for_each_entry(ptr, head, head.list) {
 162                if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) ||
 163                    atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
 164                        continue;
 165                atomic_inc(&ptr->head.users);
 166                goto out;
 167        }
 168        ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
 169        if (tomoyo_memory_ok(ptr)) {
 170                ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
 171                memmove((char *) ptr->entry.name, name, len);
 172                atomic_set(&ptr->head.users, 1);
 173                tomoyo_fill_path_info(&ptr->entry);
 174                list_add_tail(&ptr->head.list, head);
 175        } else {
 176                kfree(ptr);
 177                ptr = NULL;
 178        }
 179out:
 180        mutex_unlock(&tomoyo_policy_lock);
 181        return ptr ? &ptr->entry : NULL;
 182}
 183
 184/* Initial namespace.*/
 185struct tomoyo_policy_namespace tomoyo_kernel_namespace;
 186
 187/**
 188 * tomoyo_mm_init - Initialize mm related code.
 189 */
 190void __init tomoyo_mm_init(void)
 191{
 192        int idx;
 193        for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
 194                INIT_LIST_HEAD(&tomoyo_name_list[idx]);
 195        tomoyo_kernel_namespace.name = "<kernel>";
 196        tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
 197        tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
 198        INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
 199        tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
 200        list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
 201}
 202
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