security/tomoyo/memory.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * security/tomoyo/memory.c
   4  *
   5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   6  */
   7
   8 #include <linux/hash.h>
   9 #include <linux/slab.h>
  10 #include "common.h"
  11
  12 /**
  13  * tomoyo_warn_oom - Print out of memory warning message.
  14  *
  15  * @function: Function's name.
  16  */
  17 void tomoyo_warn_oom(const char *function)
  18 {
  19         /* Reduce error messages. */
  20         static pid_t tomoyo_last_pid;
  21         const pid_t pid = current->pid;
  22         if (tomoyo_last_pid != pid) {
  23                 printk(KERN_WARNING "ERROR: Out of memory at %s.\n",
  24                        function);
  25                 tomoyo_last_pid = pid;
  26         }
  27         if (!tomoyo_policy_loaded)
  28                 panic("MAC Initialization failed.\n");
  29 }
  30
  31 /* Memoy currently used by policy/audit log/query. */
  32 unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
  33 /* Memory quota for "policy"/"audit log"/"query". */
  34 unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT];
  35
  36 /**
  37  * tomoyo_memory_ok - Check memory quota.
  38  *
  39  * @ptr: Pointer to allocated memory.
  40  *
  41  * Returns true on success, false otherwise.
  42  *
  43  * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
  44  *
  45  * Caller holds tomoyo_policy_lock mutex.
  46  */
  47 bool tomoyo_memory_ok(void *ptr)
  48 {
  49         if (ptr) {
  50                 const size_t s = ksize(ptr);
  51                 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
  52                 if (!tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
  53                     tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
  54                     tomoyo_memory_quota[TOMOYO_MEMORY_POLICY])
  55                         return true;
  56                 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
  57         }
  58         tomoyo_warn_oom(__func__);
  59         return false;
  60 }
  61
  62 /**
  63  * tomoyo_commit_ok - Check memory quota.
  64  *
  65  * @data:   Data to copy from.
  66  * @size:   Size in byte.
  67  *
  68  * Returns pointer to allocated memory on success, NULL otherwise.
  69  * @data is zero-cleared on success.
  70  *
  71  * Caller holds tomoyo_policy_lock mutex.
  72  */
  73 void *tomoyo_commit_ok(void *data, const unsigned int size)
  74 {
  75         void *ptr = kzalloc(size, GFP_NOFS);
  76         if (tomoyo_memory_ok(ptr)) {
  77                 memmove(ptr, data, size);
  78                 memset(data, 0, size);
  79                 return ptr;
  80         }
  81         kfree(ptr);
  82         return NULL;
  83 }
  84
  85 /**
  86  * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
  87  *
  88  * @param: Pointer to "struct tomoyo_acl_param".
  89  * @idx:   Index number.
  90  *
  91  * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
  92  */
  93 struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
  94                                       const u8 idx)
  95 {
  96         struct tomoyo_group e = { };
  97         struct tomoyo_group *group = NULL;
  98         struct list_head *list;
  99         const char *group_name = tomoyo_read_token(param);
 100         bool found = false;
 101         if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
 102                 return NULL;
 103         e.group_name = tomoyo_get_name(group_name);
 104         if (!e.group_name)
 105                 return NULL;
 106         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 107                 goto out;
 108         list = &param->ns->group_list[idx];
 109         list_for_each_entry(group, list, head.list) {
 110                 if (e.group_name != group->group_name ||
 111                     atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS)
 112                         continue;
 113                 atomic_inc(&group->head.users);
 114                 found = true;
 115                 break;
 116         }
 117         if (!found) {
 118                 struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
 119                 if (entry) {
 120                         INIT_LIST_HEAD(&entry->member_list);
 121                         atomic_set(&entry->head.users, 1);
 122                         list_add_tail_rcu(&entry->head.list, list);
 123                         group = entry;
 124                         found = true;
 125                 }
 126         }
 127         mutex_unlock(&tomoyo_policy_lock);
 128 out:
 129         tomoyo_put_name(e.group_name);
 130         return found ? group : NULL;
 131 }
 132
 133 /*
 134  * tomoyo_name_list is used for holding string data used by TOMOYO.
 135  * Since same string data is likely used for multiple times (e.g.
 136  * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
 137  * "const struct tomoyo_path_info *".
 138  */
 139 struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
 140
 141 /**
 142  * tomoyo_get_name - Allocate permanent memory for string data.
 143  *
 144  * @name: The string to store into the permernent memory.
 145  *
 146  * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
 147  */
 148 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
 149 {
 150         struct tomoyo_name *ptr;
 151         unsigned int hash;
 152         int len;
 153         struct list_head *head;
 154
 155         if (!name)
 156                 return NULL;
 157         len = strlen(name) + 1;
 158         hash = full_name_hash(NULL, (const unsigned char *) name, len - 1);
 159         head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
 160         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 161                 return NULL;
 162         list_for_each_entry(ptr, head, head.list) {
 163                 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) ||
 164                     atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
 165                         continue;
 166                 atomic_inc(&ptr->head.users);
 167                 goto out;
 168         }
 169         ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
 170         if (tomoyo_memory_ok(ptr)) {
 171                 ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
 172                 memmove((char *) ptr->entry.name, name, len);
 173                 atomic_set(&ptr->head.users, 1);
 174                 tomoyo_fill_path_info(&ptr->entry);
 175                 list_add_tail(&ptr->head.list, head);
 176         } else {
 177                 kfree(ptr);
 178                 ptr = NULL;
 179         }
 180 out:
 181         mutex_unlock(&tomoyo_policy_lock);
 182         return ptr ? &ptr->entry : NULL;
 183 }
 184
 185 /* Initial namespace.*/
 186 struct tomoyo_policy_namespace tomoyo_kernel_namespace;
 187
 188 /**
 189  * tomoyo_mm_init - Initialize mm related code.
 190  */
 191 void __init tomoyo_mm_init(void)
 192 {
 193         int idx;
 194         for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
 195                 INIT_LIST_HEAD(&tomoyo_name_list[idx]);
 196         tomoyo_kernel_namespace.name = "<kernel>";
 197         tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
 198         tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
 199         INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
 200         tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
 201         list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
 202 }