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Diffstat (limited to 'security/integrity/ima/ima_iint.c')
| -rw-r--r-- | security/integrity/ima/ima_iint.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c new file mode 100644 index 000000000000..750db3c993a7 --- /dev/null +++ b/security/integrity/ima/ima_iint.c @@ -0,0 +1,185 @@ +/* + * 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 radix tree. + */ +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/radix-tree.h> +#include "ima.h" + +#define ima_iint_delete ima_inode_free + +RADIX_TREE(ima_iint_store, GFP_ATOMIC); +DEFINE_SPINLOCK(ima_iint_lock); + +static struct kmem_cache *iint_cache __read_mostly; + +/* 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; + + rcu_read_lock(); + iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode); + if (!iint) + goto out; + kref_get(&iint->refcount); +out: + rcu_read_unlock(); + return iint; +} + +/* Allocate memory for the iint associated with the inode + * from the iint_cache slab, initialize the iint, and + * insert it into the radix tree. + * + * On success return a pointer to the iint; on failure return NULL. + */ +struct ima_iint_cache *ima_iint_insert(struct inode *inode) +{ + struct ima_iint_cache *iint = NULL; + int rc = 0; + + if (!ima_initialized) + return iint; + iint = kmem_cache_alloc(iint_cache, GFP_KERNEL); + if (!iint) + return iint; + + rc = radix_tree_preload(GFP_KERNEL); + if (rc < 0) + goto out; + + spin_lock(&ima_iint_lock); + rc = radix_tree_insert(&ima_iint_store, (unsigned long)inode, iint); + spin_unlock(&ima_iint_lock); +out: + if (rc < 0) { + kmem_cache_free(iint_cache, iint); + if (rc == -EEXIST) { + iint = radix_tree_lookup(&ima_iint_store, + (unsigned long)inode); + } else + iint = NULL; + } + radix_tree_preload_end(); + return iint; +} + +/** + * ima_inode_alloc - allocate an iint associated with an inode + * @inode: pointer to the inode + * + * Return 0 on success, 1 on failure. + */ +int ima_inode_alloc(struct inode *inode) +{ + struct ima_iint_cache *iint; + + if (!ima_initialized) + return 0; + + iint = ima_iint_insert(inode); + if (!iint) + return 1; + return 0; +} + +/* ima_iint_find_insert_get - get the iint associated with an inode + * + * Most insertions are done at inode_alloc, except those allocated + * before late_initcall. When the iint does not exist, allocate it, + * initialize and insert it, and increment the iint refcount. + * + * (Can't initialize at security_initcall before any inodes are + * allocated, got to wait at least until proc_init.) + * + * Return the iint. + */ +struct ima_iint_cache *ima_iint_find_insert_get(struct inode *inode) +{ + struct ima_iint_cache *iint = NULL; + + iint = ima_iint_find_get(inode); + if (iint) + return iint; + + iint = ima_iint_insert(inode); + if (iint) + kref_get(&iint->refcount); + + return iint; +} + +/* 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; + kref_set(&iint->refcount, 1); + kmem_cache_free(iint_cache, iint); +} + +void iint_rcu_free(struct rcu_head *rcu_head) +{ + struct ima_iint_cache *iint = container_of(rcu_head, + struct ima_iint_cache, rcu); + kref_put(&iint->refcount, iint_free); +} + +/** + * ima_iint_delete - called on integrity_inode_free + * @inode: pointer to the inode + * + * Free the integrity information(iint) associated with an inode. + */ +void ima_iint_delete(struct inode *inode) +{ + struct ima_iint_cache *iint; + + if (!ima_initialized) + return; + spin_lock(&ima_iint_lock); + iint = radix_tree_delete(&ima_iint_store, (unsigned long)inode); + spin_unlock(&ima_iint_lock); + if (iint) + call_rcu(&iint->rcu, iint_rcu_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_set(&iint->refcount, 1); +} + +void ima_iintcache_init(void) +{ + iint_cache = + kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0, + SLAB_PANIC, init_once); +} |