165 lines
3.7 KiB
C
165 lines
3.7 KiB
C
/*
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* Copyright (C) 2008 IBM Corporation
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*
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* Authors:
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* Mimi Zohar <zohar@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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* File: integrity_iint.c
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* - implements the integrity hooks: integrity_inode_alloc,
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* integrity_inode_free
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* - cache integrity information associated with an inode
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* using a rbtree tree.
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*/
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/rbtree.h>
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#include "integrity.h"
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static struct rb_root integrity_iint_tree = RB_ROOT;
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static DEFINE_RWLOCK(integrity_iint_lock);
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static struct kmem_cache *iint_cache __read_mostly;
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int iint_initialized;
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/*
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* __integrity_iint_find - return the iint associated with an inode
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*/
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static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
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{
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struct integrity_iint_cache *iint;
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struct rb_node *n = integrity_iint_tree.rb_node;
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while (n) {
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iint = rb_entry(n, struct integrity_iint_cache, rb_node);
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if (inode < iint->inode)
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n = n->rb_left;
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else if (inode > iint->inode)
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n = n->rb_right;
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else
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break;
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}
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if (!n)
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return NULL;
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return iint;
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}
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/*
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* integrity_iint_find - return the iint associated with an inode
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*/
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struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
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{
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struct integrity_iint_cache *iint;
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if (!IS_IMA(inode))
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return NULL;
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read_lock(&integrity_iint_lock);
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iint = __integrity_iint_find(inode);
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read_unlock(&integrity_iint_lock);
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return iint;
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}
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static void iint_free(struct integrity_iint_cache *iint)
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{
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iint->version = 0;
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iint->flags = 0UL;
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iint->ima_status = INTEGRITY_UNKNOWN;
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iint->evm_status = INTEGRITY_UNKNOWN;
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kmem_cache_free(iint_cache, iint);
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}
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/**
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* integrity_inode_get - find or allocate an iint associated with an inode
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* @inode: pointer to the inode
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* @return: allocated iint
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*
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* Caller must lock i_mutex
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*/
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struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
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{
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struct rb_node **p;
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struct rb_node *node, *parent = NULL;
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struct integrity_iint_cache *iint, *test_iint;
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iint = integrity_iint_find(inode);
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if (iint)
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return iint;
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iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
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if (!iint)
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return NULL;
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write_lock(&integrity_iint_lock);
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p = &integrity_iint_tree.rb_node;
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while (*p) {
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parent = *p;
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test_iint = rb_entry(parent, struct integrity_iint_cache,
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rb_node);
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if (inode < test_iint->inode)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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}
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iint->inode = inode;
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node = &iint->rb_node;
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inode->i_flags |= S_IMA;
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rb_link_node(node, parent, p);
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rb_insert_color(node, &integrity_iint_tree);
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write_unlock(&integrity_iint_lock);
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return iint;
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}
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/**
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* integrity_inode_free - called on security_inode_free
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* @inode: pointer to the inode
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*
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* Free the integrity information(iint) associated with an inode.
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*/
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void integrity_inode_free(struct inode *inode)
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{
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struct integrity_iint_cache *iint;
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if (!IS_IMA(inode))
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return;
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write_lock(&integrity_iint_lock);
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iint = __integrity_iint_find(inode);
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rb_erase(&iint->rb_node, &integrity_iint_tree);
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write_unlock(&integrity_iint_lock);
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iint_free(iint);
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}
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static void init_once(void *foo)
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{
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struct integrity_iint_cache *iint = foo;
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memset(iint, 0, sizeof *iint);
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iint->version = 0;
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iint->flags = 0UL;
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iint->ima_status = INTEGRITY_UNKNOWN;
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iint->evm_status = INTEGRITY_UNKNOWN;
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}
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static int __init integrity_iintcache_init(void)
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{
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iint_cache =
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kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
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0, SLAB_PANIC, init_once);
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iint_initialized = 1;
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return 0;
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}
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security_initcall(integrity_iintcache_init);
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