diff options
Diffstat (limited to 'security/integrity/iint.c')
| -rw-r--r-- | security/integrity/iint.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/security/integrity/iint.c b/security/integrity/iint.c new file mode 100644 index 00000000000..399641c3e84 --- /dev/null +++ b/security/integrity/iint.c @@ -0,0 +1,172 @@ +/* + * 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: integrity_iint.c + * - implements the integrity hooks: integrity_inode_alloc, + * integrity_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 "integrity.h" + +static struct rb_root integrity_iint_tree = RB_ROOT; +static DEFINE_SPINLOCK(integrity_iint_lock); +static struct kmem_cache *iint_cache __read_mostly; + +int iint_initialized; + +/* + * __integrity_iint_find - return the iint associated with an inode + */ +static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode) +{ + struct integrity_iint_cache *iint; + struct rb_node *n = integrity_iint_tree.rb_node; + + assert_spin_locked(&integrity_iint_lock); + + while (n) { + iint = rb_entry(n, struct integrity_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; +} + +/* + * integrity_iint_find - return the iint associated with an inode + */ +struct integrity_iint_cache *integrity_iint_find(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!IS_IMA(inode)) + return NULL; + + spin_lock(&integrity_iint_lock); + iint = __integrity_iint_find(inode); + spin_unlock(&integrity_iint_lock); + + return iint; +} + +static void iint_free(struct integrity_iint_cache *iint) +{ + iint->version = 0; + iint->flags = 0UL; + iint->evm_status = INTEGRITY_UNKNOWN; + kmem_cache_free(iint_cache, iint); +} + +/** + * integrity_inode_alloc - allocate an iint associated with an inode + * @inode: pointer to the inode + */ +int integrity_inode_alloc(struct inode *inode) +{ + struct rb_node **p; + struct rb_node *new_node, *parent = NULL; + struct integrity_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(&integrity_iint_lock); + + p = &integrity_iint_tree.rb_node; + while (*p) { + parent = *p; + test_iint = rb_entry(parent, struct integrity_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, &integrity_iint_tree); + + spin_unlock(&integrity_iint_lock); + mutex_unlock(&inode->i_mutex); /* i_flags */ + + return 0; +out_err: + spin_unlock(&integrity_iint_lock); + mutex_unlock(&inode->i_mutex); /* i_flags */ + iint_free(new_iint); + + return rc; +} + +/** + * integrity_inode_free - called on security_inode_free + * @inode: pointer to the inode + * + * Free the integrity information(iint) associated with an inode. + */ +void integrity_inode_free(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!IS_IMA(inode)) + return; + + spin_lock(&integrity_iint_lock); + iint = __integrity_iint_find(inode); + rb_erase(&iint->rb_node, &integrity_iint_tree); + spin_unlock(&integrity_iint_lock); + + iint_free(iint); +} + +static void init_once(void *foo) +{ + struct integrity_iint_cache *iint = foo; + + memset(iint, 0, sizeof *iint); + iint->version = 0; + iint->flags = 0UL; + mutex_init(&iint->mutex); + iint->evm_status = INTEGRITY_UNKNOWN; +} + +static int __init integrity_iintcache_init(void) +{ + iint_cache = + kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), + 0, SLAB_PANIC, init_once); + iint_initialized = 1; + return 0; +} +security_initcall(integrity_iintcache_init); |