integrity: move ima inode integrity data management

Move the inode integrity data(iint) management up to the integrity directory
in order to share the iint among the different integrity models.

Changelog:
- don't define MAX_DIGEST_SIZE
- rename several globally visible 'ima_' prefixed functions, structs,
  locks, etc to 'integrity_'
- replace '20' with SHA1_DIGEST_SIZE
- reflect location change in appropriate Kconfig and Makefiles
- remove unnecessary initialization of iint_initialized to 0
- rebased on current ima_iint.c
- define integrity_iint_store/lock as static

There should be no other functional changes.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>

1 files changed, 170 insertions, 0 deletions

diff --git a/security/integrity/iint.c b/security/integrity/iint.c
new file mode 100644
index 000000000000..d17de48bd6cc
--- /dev/null
+++ b/security/integrity/iint.c
@@ -0,0 +1,170 @@
+/*
+ * 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;
+        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);
+}
+
+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);