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 /* Memoy currently used by policy/audit log/query. */
  31 unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
  32 /* Memory quota for "policy"/"audit log"/"query". */
  33 unsigned 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  */
  46 bool 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  */
  72 void *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  */
  92 struct 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);
 127 out:
 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  */
 138 struct 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  */
 147 const 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(NULL, (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         }
 179 out:
 180         mutex_unlock(&tomoyo_policy_lock);
 181         return ptr ? &ptr->entry : NULL;
 182 }
 183
 184 /* Initial namespace.*/
 185 struct tomoyo_policy_namespace tomoyo_kernel_namespace;
 186
 187 /**
 188  * tomoyo_mm_init - Initialize mm related code.
 189  */
 190 void __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 }