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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 
 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);
 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);
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 }
208 

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