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
  23         if (tomoyo_last_pid != pid) {
  24                 pr_warn("ERROR: Out of memory at %s.\n", 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
  52                 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
  53                 if (!tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
  54                     tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
  55                     tomoyo_memory_quota[TOMOYO_MEMORY_POLICY])
  56                         return true;
  57                 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
  58         }
  59         tomoyo_warn_oom(__func__);
  60         return false;
  61 }
  62
  63 /**
  64  * tomoyo_commit_ok - Check memory quota.
  65  *
  66  * @data:   Data to copy from.
  67  * @size:   Size in byte.
  68  *
  69  * Returns pointer to allocated memory on success, NULL otherwise.
  70  * @data is zero-cleared on success.
  71  *
  72  * Caller holds tomoyo_policy_lock mutex.
  73  */
  74 void *tomoyo_commit_ok(void *data, const unsigned int size)
  75 {
  76         void *ptr = kzalloc(size, GFP_NOFS | __GFP_NOWARN);
  77
  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_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
  89  *
  90  * @param: Pointer to "struct tomoyo_acl_param".
  91  * @idx:   Index number.
  92  *
  93  * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
  94  */
  95 struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
  96                                       const u8 idx)
  97 {
  98         struct tomoyo_group e = { };
  99         struct tomoyo_group *group = NULL;
 100         struct list_head *list;
 101         const char *group_name = tomoyo_read_token(param);
 102         bool found = false;
 103
 104         if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
 105                 return NULL;
 106         e.group_name = tomoyo_get_name(group_name);
 107         if (!e.group_name)
 108                 return NULL;
 109         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 110                 goto out;
 111         list = &param->ns->group_list[idx];
 112         list_for_each_entry(group, list, head.list) {
 113                 if (e.group_name != group->group_name ||
 114                     atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS)
 115                         continue;
 116                 atomic_inc(&group->head.users);
 117                 found = true;
 118                 break;
 119         }
 120         if (!found) {
 121                 struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
 122
 123                 if (entry) {
 124                         INIT_LIST_HEAD(&entry->member_list);
 125                         atomic_set(&entry->head.users, 1);
 126                         list_add_tail_rcu(&entry->head.list, list);
 127                         group = entry;
 128                         found = true;
 129                 }
 130         }
 131         mutex_unlock(&tomoyo_policy_lock);
 132 out:
 133         tomoyo_put_name(e.group_name);
 134         return found ? group : NULL;
 135 }
 136
 137 /*
 138  * tomoyo_name_list is used for holding string data used by TOMOYO.
 139  * Since same string data is likely used for multiple times (e.g.
 140  * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
 141  * "const struct tomoyo_path_info *".
 142  */
 143 struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
 144
 145 /**
 146  * tomoyo_get_name - Allocate permanent memory for string data.
 147  *
 148  * @name: The string to store into the permernent memory.
 149  *
 150  * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
 151  */
 152 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
 153 {
 154         struct tomoyo_name *ptr;
 155         unsigned int hash;
 156         int len;
 157         struct list_head *head;
 158
 159         if (!name)
 160                 return NULL;
 161         len = strlen(name) + 1;
 162         hash = full_name_hash(NULL, (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, head.list) {
 167                 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) ||
 168                     atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
 169                         continue;
 170                 atomic_inc(&ptr->head.users);
 171                 goto out;
 172         }
 173         ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS | __GFP_NOWARN);
 174         if (tomoyo_memory_ok(ptr)) {
 175                 ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
 176                 memmove((char *) ptr->entry.name, name, len);
 177                 atomic_set(&ptr->head.users, 1);
 178                 tomoyo_fill_path_info(&ptr->entry);
 179                 list_add_tail(&ptr->head.list, head);
 180         } else {
 181                 kfree(ptr);
 182                 ptr = NULL;
 183         }
 184 out:
 185         mutex_unlock(&tomoyo_policy_lock);
 186         return ptr ? &ptr->entry : NULL;
 187 }
 188
 189 /* Initial namespace.*/
 190 struct tomoyo_policy_namespace tomoyo_kernel_namespace;
 191
 192 /**
 193  * tomoyo_mm_init - Initialize mm related code.
 194  */
 195 void __init tomoyo_mm_init(void)
 196 {
 197         int idx;
 198
 199         for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
 200                 INIT_LIST_HEAD(&tomoyo_name_list[idx]);
 201         tomoyo_kernel_namespace.name = "<kernel>";
 202         tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
 203         tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
 204         INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
 205         tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
 206         list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
 207 }