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TOMOYO Linux Cross Reference
Linux/security/tomoyo/memory.c

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  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 }
203 

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