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);
+}