security/tomoyo/memory.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * security/tomoyo/memory.c
0004  *
0005  * Copyright (C) 2005-2011  NTT DATA CORPORATION
0006  */
0007
0008 #include <linux/hash.h>
0009 #include <linux/slab.h>
0010 #include "common.h"
0011
0012 /**
0013  * tomoyo_warn_oom - Print out of memory warning message.
0014  *
0015  * @function: Function's name.
0016  */
0017 void tomoyo_warn_oom(const char *function)
0018 {
0019     /* Reduce error messages. */
0020     static pid_t tomoyo_last_pid;
0021     const pid_t pid = current->pid;
0022
0023     if (tomoyo_last_pid != pid) {
0024         pr_warn("ERROR: Out of memory at %s.\n", function);
0025         tomoyo_last_pid = pid;
0026     }
0027     if (!tomoyo_policy_loaded)
0028         panic("MAC Initialization failed.\n");
0029 }
0030
0031 /* Memoy currently used by policy/audit log/query. */
0032 unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
0033 /* Memory quota for "policy"/"audit log"/"query". */
0034 unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT];
0035
0036 /**
0037  * tomoyo_memory_ok - Check memory quota.
0038  *
0039  * @ptr: Pointer to allocated memory.
0040  *
0041  * Returns true on success, false otherwise.
0042  *
0043  * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
0044  *
0045  * Caller holds tomoyo_policy_lock mutex.
0046  */
0047 bool tomoyo_memory_ok(void *ptr)
0048 {
0049     if (ptr) {
0050         const size_t s = ksize(ptr);
0051
0052         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
0053         if (!tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
0054             tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
0055             tomoyo_memory_quota[TOMOYO_MEMORY_POLICY])
0056             return true;
0057         tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
0058     }
0059     tomoyo_warn_oom(__func__);
0060     return false;
0061 }
0062
0063 /**
0064  * tomoyo_commit_ok - Check memory quota.
0065  *
0066  * @data:   Data to copy from.
0067  * @size:   Size in byte.
0068  *
0069  * Returns pointer to allocated memory on success, NULL otherwise.
0070  * @data is zero-cleared on success.
0071  *
0072  * Caller holds tomoyo_policy_lock mutex.
0073  */
0074 void *tomoyo_commit_ok(void *data, const unsigned int size)
0075 {
0076     void *ptr = kzalloc(size, GFP_NOFS | __GFP_NOWARN);
0077
0078     if (tomoyo_memory_ok(ptr)) {
0079         memmove(ptr, data, size);
0080         memset(data, 0, size);
0081         return ptr;
0082     }
0083     kfree(ptr);
0084     return NULL;
0085 }
0086
0087 /**
0088  * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
0089  *
0090  * @param: Pointer to "struct tomoyo_acl_param".
0091  * @idx:   Index number.
0092  *
0093  * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
0094  */
0095 struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
0096                       const u8 idx)
0097 {
0098     struct tomoyo_group e = { };
0099     struct tomoyo_group *group = NULL;
0100     struct list_head *list;
0101     const char *group_name = tomoyo_read_token(param);
0102     bool found = false;
0103
0104     if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
0105         return NULL;
0106     e.group_name = tomoyo_get_name(group_name);
0107     if (!e.group_name)
0108         return NULL;
0109     if (mutex_lock_interruptible(&tomoyo_policy_lock))
0110         goto out;
0111     list = &param->ns->group_list[idx];
0112     list_for_each_entry(group, list, head.list) {
0113         if (e.group_name != group->group_name ||
0114             atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS)
0115             continue;
0116         atomic_inc(&group->head.users);
0117         found = true;
0118         break;
0119     }
0120     if (!found) {
0121         struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
0122
0123         if (entry) {
0124             INIT_LIST_HEAD(&entry->member_list);
0125             atomic_set(&entry->head.users, 1);
0126             list_add_tail_rcu(&entry->head.list, list);
0127             group = entry;
0128             found = true;
0129         }
0130     }
0131     mutex_unlock(&tomoyo_policy_lock);
0132 out:
0133     tomoyo_put_name(e.group_name);
0134     return found ? group : NULL;
0135 }
0136
0137 /*
0138  * tomoyo_name_list is used for holding string data used by TOMOYO.
0139  * Since same string data is likely used for multiple times (e.g.
0140  * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
0141  * "const struct tomoyo_path_info *".
0142  */
0143 struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
0144
0145 /**
0146  * tomoyo_get_name - Allocate permanent memory for string data.
0147  *
0148  * @name: The string to store into the permernent memory.
0149  *
0150  * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
0151  */
0152 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
0153 {
0154     struct tomoyo_name *ptr;
0155     unsigned int hash;
0156     int len;
0157     struct list_head *head;
0158
0159     if (!name)
0160         return NULL;
0161     len = strlen(name) + 1;
0162     hash = full_name_hash(NULL, (const unsigned char *) name, len - 1);
0163     head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
0164     if (mutex_lock_interruptible(&tomoyo_policy_lock))
0165         return NULL;
0166     list_for_each_entry(ptr, head, head.list) {
0167         if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) ||
0168             atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
0169             continue;
0170         atomic_inc(&ptr->head.users);
0171         goto out;
0172     }
0173     ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS | __GFP_NOWARN);
0174     if (tomoyo_memory_ok(ptr)) {
0175         ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
0176         memmove((char *) ptr->entry.name, name, len);
0177         atomic_set(&ptr->head.users, 1);
0178         tomoyo_fill_path_info(&ptr->entry);
0179         list_add_tail(&ptr->head.list, head);
0180     } else {
0181         kfree(ptr);
0182         ptr = NULL;
0183     }
0184 out:
0185     mutex_unlock(&tomoyo_policy_lock);
0186     return ptr ? &ptr->entry : NULL;
0187 }
0188
0189 /* Initial namespace.*/
0190 struct tomoyo_policy_namespace tomoyo_kernel_namespace;
0191
0192 /**
0193  * tomoyo_mm_init - Initialize mm related code.
0194  */
0195 void __init tomoyo_mm_init(void)
0196 {
0197     int idx;
0198
0199     for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
0200         INIT_LIST_HEAD(&tomoyo_name_list[idx]);
0201     tomoyo_kernel_namespace.name = "<kernel>";
0202     tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
0203     tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
0204     INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
0205     tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
0206     list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
0207 }