1 /* 2 * Copyright (C) 2008 IBM Corporation 3 * 4 * Authors: 5 * Mimi Zohar <zohar@us.ibm.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License as 9 * published by the Free Software Foundation, version 2 of the 10 * License. 11 * 12 * File: ima_iint.c 13 * - implements the IMA hooks: ima_inode_alloc, ima_inode_free 14 * - cache integrity information associated with an inode 15 * using a radix tree. 16 */ 17 #include <linux/module.h> 18 #include <linux/spinlock.h> 19 #include <linux/radix-tree.h> 20 #include "ima.h" 21 22 RADIX_TREE(ima_iint_store, GFP_ATOMIC); 23 DEFINE_SPINLOCK(ima_iint_lock); 24 25 static struct kmem_cache *iint_cache __read_mostly; 26 27 /* ima_iint_find_get - return the iint associated with an inode 28 * 29 * ima_iint_find_get gets a reference to the iint. Caller must 30 * remember to put the iint reference. 31 */ 32 struct ima_iint_cache *ima_iint_find_get(struct inode *inode) 33 { 34 struct ima_iint_cache *iint; 35 36 rcu_read_lock(); 37 iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode); 38 if (!iint) 39 goto out; 40 kref_get(&iint->refcount); 41 out: 42 rcu_read_unlock(); 43 return iint; 44 } 45 46 /** 47 * ima_inode_alloc - allocate an iint associated with an inode 48 * @inode: pointer to the inode 49 */ 50 int ima_inode_alloc(struct inode *inode) 51 { 52 struct ima_iint_cache *iint = NULL; 53 int rc = 0; 54 55 iint = kmem_cache_alloc(iint_cache, GFP_NOFS); 56 if (!iint) 57 return -ENOMEM; 58 59 rc = radix_tree_preload(GFP_NOFS); 60 if (rc < 0) 61 goto out; 62 63 spin_lock(&ima_iint_lock); 64 rc = radix_tree_insert(&ima_iint_store, (unsigned long)inode, iint); 65 spin_unlock(&ima_iint_lock); 66 radix_tree_preload_end(); 67 out: 68 if (rc < 0) 69 kmem_cache_free(iint_cache, iint); 70 71 return rc; 72 } 73 74 /* iint_free - called when the iint refcount goes to zero */ 75 void iint_free(struct kref *kref) 76 { 77 struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache, 78 refcount); 79 iint->version = 0; 80 iint->flags = 0UL; 81 if (iint->readcount != 0) { 82 printk(KERN_INFO "%s: readcount: %ld\n", __FUNCTION__, 83 iint->readcount); 84 iint->readcount = 0; 85 } 86 if (iint->writecount != 0) { 87 printk(KERN_INFO "%s: writecount: %ld\n", __FUNCTION__, 88 iint->writecount); 89 iint->writecount = 0; 90 } 91 if (iint->opencount != 0) { 92 printk(KERN_INFO "%s: opencount: %ld\n", __FUNCTION__, 93 iint->opencount); 94 iint->opencount = 0; 95 } 96 kref_set(&iint->refcount, 1); 97 kmem_cache_free(iint_cache, iint); 98 } 99 100 void iint_rcu_free(struct rcu_head *rcu_head) 101 { 102 struct ima_iint_cache *iint = container_of(rcu_head, 103 struct ima_iint_cache, rcu); 104 kref_put(&iint->refcount, iint_free); 105 } 106 107 /** 108 * ima_inode_free - called on security_inode_free 109 * @inode: pointer to the inode 110 * 111 * Free the integrity information(iint) associated with an inode. 112 */ 113 void ima_inode_free(struct inode *inode) 114 { 115 struct ima_iint_cache *iint; 116 117 spin_lock(&ima_iint_lock); 118 iint = radix_tree_delete(&ima_iint_store, (unsigned long)inode); 119 spin_unlock(&ima_iint_lock); 120 if (iint) 121 call_rcu(&iint->rcu, iint_rcu_free); 122 } 123 124 static void init_once(void *foo) 125 { 126 struct ima_iint_cache *iint = foo; 127 128 memset(iint, 0, sizeof *iint); 129 iint->version = 0; 130 iint->flags = 0UL; 131 mutex_init(&iint->mutex); 132 iint->readcount = 0; 133 iint->writecount = 0; 134 iint->opencount = 0; 135 kref_set(&iint->refcount, 1); 136 } 137 138 static int __init ima_iintcache_init(void) 139 { 140 iint_cache = 141 kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0, 142 SLAB_PANIC, init_once); 143 return 0; 144 } 145 security_initcall(ima_iintcache_init); 146