linux/security/integrity/ima/ima_iint.c
Eric Paris 196f518128 IMA: explicit IMA i_flag to remove global lock on inode_delete
Currently for every removed inode IMA must take a global lock and search
the IMA rbtree looking for an associated integrity structure.  Instead
we explicitly mark an inode when we add an integrity structure so we
only have to take the global lock and do the removal if it exists.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 11:37:19 -07:00

175 lines
3.6 KiB
C

/*
* Copyright (C) 2008 IBM Corporation
*
* Authors:
* Mimi Zohar <zohar@us.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
* File: ima_iint.c
* - implements the IMA hooks: ima_inode_alloc, ima_inode_free
* - cache integrity information associated with an inode
* using a rbtree tree.
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include "ima.h"
static struct rb_root ima_iint_tree = RB_ROOT;
static DEFINE_SPINLOCK(ima_iint_lock);
static struct kmem_cache *iint_cache __read_mostly;
int iint_initialized = 0;
/*
* __ima_iint_find - return the iint associated with an inode
*/
static struct ima_iint_cache *__ima_iint_find(struct inode *inode)
{
struct ima_iint_cache *iint;
struct rb_node *n = ima_iint_tree.rb_node;
assert_spin_locked(&ima_iint_lock);
while (n) {
iint = rb_entry(n, struct ima_iint_cache, rb_node);
if (inode < iint->inode)
n = n->rb_left;
else if (inode > iint->inode)
n = n->rb_right;
else
break;
}
if (!n)
return NULL;
return iint;
}
/*
* ima_iint_find - return the iint associated with an inode
*/
struct ima_iint_cache *ima_iint_find(struct inode *inode)
{
struct ima_iint_cache *iint;
if (!IS_IMA(inode))
return NULL;
spin_lock(&ima_iint_lock);
iint = __ima_iint_find(inode);
spin_unlock(&ima_iint_lock);
return iint;
}
static void iint_free(struct ima_iint_cache *iint)
{
iint->version = 0;
iint->flags = 0UL;
kmem_cache_free(iint_cache, iint);
}
/**
* ima_inode_alloc - allocate an iint associated with an inode
* @inode: pointer to the inode
*/
int ima_inode_alloc(struct inode *inode)
{
struct rb_node **p;
struct rb_node *new_node, *parent = NULL;
struct ima_iint_cache *new_iint, *test_iint;
int rc;
new_iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
if (!new_iint)
return -ENOMEM;
new_iint->inode = inode;
new_node = &new_iint->rb_node;
mutex_lock(&inode->i_mutex); /* i_flags */
spin_lock(&ima_iint_lock);
p = &ima_iint_tree.rb_node;
while (*p) {
parent = *p;
test_iint = rb_entry(parent, struct ima_iint_cache, rb_node);
rc = -EEXIST;
if (inode < test_iint->inode)
p = &(*p)->rb_left;
else if (inode > test_iint->inode)
p = &(*p)->rb_right;
else
goto out_err;
}
inode->i_flags |= S_IMA;
rb_link_node(new_node, parent, p);
rb_insert_color(new_node, &ima_iint_tree);
spin_unlock(&ima_iint_lock);
mutex_unlock(&inode->i_mutex); /* i_flags */
return 0;
out_err:
spin_unlock(&ima_iint_lock);
mutex_unlock(&inode->i_mutex); /* i_flags */
iint_free(new_iint);
return rc;
}
/**
* ima_inode_free - called on security_inode_free
* @inode: pointer to the inode
*
* Free the integrity information(iint) associated with an inode.
*/
void ima_inode_free(struct inode *inode)
{
struct ima_iint_cache *iint;
if (inode->i_readcount)
printk(KERN_INFO "%s: readcount: %u\n", __func__, inode->i_readcount);
inode->i_readcount = 0;
if (!IS_IMA(inode))
return;
spin_lock(&ima_iint_lock);
iint = __ima_iint_find(inode);
rb_erase(&iint->rb_node, &ima_iint_tree);
spin_unlock(&ima_iint_lock);
iint_free(iint);
}
static void init_once(void *foo)
{
struct ima_iint_cache *iint = foo;
memset(iint, 0, sizeof *iint);
iint->version = 0;
iint->flags = 0UL;
mutex_init(&iint->mutex);
}
static int __init ima_iintcache_init(void)
{
iint_cache =
kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0,
SLAB_PANIC, init_once);
iint_initialized = 1;
return 0;
}
security_initcall(ima_iintcache_init);