| /* |
| * 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_get - return the iint associated with an inode |
| * |
| * ima_iint_find_get gets a reference to the iint. Caller must |
| * remember to put the iint reference. |
| */ |
| struct ima_iint_cache *ima_iint_find_get(struct inode *inode) |
| { |
| struct ima_iint_cache *iint; |
| |
| spin_lock(&ima_iint_lock); |
| iint = __ima_iint_find(inode); |
| if (iint) |
| kref_get(&iint->refcount); |
| spin_unlock(&ima_iint_lock); |
| |
| return 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; |
| |
| 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; |
| } |
| |
| rb_link_node(new_node, parent, p); |
| rb_insert_color(new_node, &ima_iint_tree); |
| |
| spin_unlock(&ima_iint_lock); |
| |
| return 0; |
| out_err: |
| spin_unlock(&ima_iint_lock); |
| kref_put(&new_iint->refcount, iint_free); |
| return rc; |
| } |
| |
| /* iint_free - called when the iint refcount goes to zero */ |
| void iint_free(struct kref *kref) |
| { |
| struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache, |
| refcount); |
| iint->version = 0; |
| iint->flags = 0UL; |
| if (iint->readcount != 0) { |
| printk(KERN_INFO "%s: readcount: %u\n", __func__, |
| iint->readcount); |
| iint->readcount = 0; |
| } |
| if (iint->writecount != 0) { |
| printk(KERN_INFO "%s: writecount: %u\n", __func__, |
| iint->writecount); |
| iint->writecount = 0; |
| } |
| kref_init(&iint->refcount); |
| kmem_cache_free(iint_cache, iint); |
| } |
| |
| /** |
| * 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; |
| |
| spin_lock(&ima_iint_lock); |
| iint = __ima_iint_find(inode); |
| if (iint) |
| rb_erase(&iint->rb_node, &ima_iint_tree); |
| spin_unlock(&ima_iint_lock); |
| if (iint) |
| kref_put(&iint->refcount, iint_free); |
| } |
| |
| 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); |
| iint->readcount = 0; |
| iint->writecount = 0; |
| kref_init(&iint->refcount); |
| } |
| |
| 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); |