150 lines
3.4 KiB
C
150 lines
3.4 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: ima_iint.c
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* - implements the IMA hooks: ima_inode_alloc, ima_inode_free
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* - cache integrity information associated with an inode
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* using a radix tree.
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*/
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/radix-tree.h>
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#include "ima.h"
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RADIX_TREE(ima_iint_store, GFP_ATOMIC);
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DEFINE_SPINLOCK(ima_iint_lock);
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static struct kmem_cache *iint_cache __read_mostly;
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/* ima_iint_find_get - return the iint associated with an inode
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*
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* ima_iint_find_get gets a reference to the iint. Caller must
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* remember to put the iint reference.
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*/
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struct ima_iint_cache *ima_iint_find_get(struct inode *inode)
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{
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struct ima_iint_cache *iint;
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rcu_read_lock();
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iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode);
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if (!iint)
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goto out;
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kref_get(&iint->refcount);
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out:
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rcu_read_unlock();
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return iint;
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}
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/**
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* ima_inode_alloc - allocate an iint associated with an inode
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* @inode: pointer to the inode
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*/
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int ima_inode_alloc(struct inode *inode)
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{
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struct ima_iint_cache *iint = NULL;
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int rc = 0;
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if (!ima_initialized)
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return 0;
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iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
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if (!iint)
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return -ENOMEM;
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rc = radix_tree_preload(GFP_NOFS);
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if (rc < 0)
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goto out;
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spin_lock(&ima_iint_lock);
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rc = radix_tree_insert(&ima_iint_store, (unsigned long)inode, iint);
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spin_unlock(&ima_iint_lock);
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out:
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if (rc < 0)
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kmem_cache_free(iint_cache, iint);
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radix_tree_preload_end();
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return rc;
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}
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/* iint_free - called when the iint refcount goes to zero */
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void iint_free(struct kref *kref)
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{
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struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache,
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refcount);
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iint->version = 0;
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iint->flags = 0UL;
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if (iint->readcount != 0) {
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printk(KERN_INFO "%s: readcount: %ld\n", __FUNCTION__,
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iint->readcount);
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iint->readcount = 0;
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}
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if (iint->writecount != 0) {
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printk(KERN_INFO "%s: writecount: %ld\n", __FUNCTION__,
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iint->writecount);
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iint->writecount = 0;
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}
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if (iint->opencount != 0) {
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printk(KERN_INFO "%s: opencount: %ld\n", __FUNCTION__,
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iint->opencount);
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iint->opencount = 0;
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}
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kref_set(&iint->refcount, 1);
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kmem_cache_free(iint_cache, iint);
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}
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void iint_rcu_free(struct rcu_head *rcu_head)
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{
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struct ima_iint_cache *iint = container_of(rcu_head,
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struct ima_iint_cache, rcu);
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kref_put(&iint->refcount, iint_free);
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}
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/**
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* ima_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 ima_inode_free(struct inode *inode)
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{
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struct ima_iint_cache *iint;
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if (!ima_initialized)
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return;
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spin_lock(&ima_iint_lock);
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iint = radix_tree_delete(&ima_iint_store, (unsigned long)inode);
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spin_unlock(&ima_iint_lock);
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if (iint)
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call_rcu(&iint->rcu, iint_rcu_free);
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}
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static void init_once(void *foo)
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{
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struct ima_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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mutex_init(&iint->mutex);
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iint->readcount = 0;
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iint->writecount = 0;
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iint->opencount = 0;
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kref_set(&iint->refcount, 1);
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}
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void __init ima_iintcache_init(void)
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{
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iint_cache =
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kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0,
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SLAB_PANIC, init_once);
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}
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