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>

include/linux/ima.h

@@ -15,8 +15,6 @@ struct linux_binprm;
 
 #ifdef CONFIG_IMA
 extern int ima_bprm_check(struct linux_binprm *bprm);
-extern int ima_inode_alloc(struct inode *inode);
-extern void ima_inode_free(struct inode *inode);
 extern int ima_file_check(struct file *file, int mask);
 extern void ima_file_free(struct file *file);
 extern int ima_file_mmap(struct file *file, unsigned long prot);
@@ -27,16 +25,6 @@ static inline int ima_bprm_check(struct linux_binprm *bprm)
 	return 0;
 }
 
-static inline int ima_inode_alloc(struct inode *inode)
-{
-	return 0;
-}
-
-static inline void ima_inode_free(struct inode *inode)
-{
-	return;
-}
-
 static inline int ima_file_check(struct file *file, int mask)
 {
 	return 0;
@@ -51,6 +39,5 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
 {
 	return 0;
 }
-
 #endif /* CONFIG_IMA_H */
 #endif /* _LINUX_IMA_H */

include/linux/integrity.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2009 IBM Corporation
+ * Author: 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.
+ */
+
+#ifndef _LINUX_INTEGRITY_H
+#define _LINUX_INTEGRITY_H
+
+#include <linux/fs.h>
+
+#ifdef CONFIG_INTEGRITY
+extern int integrity_inode_alloc(struct inode *inode);
+extern void integrity_inode_free(struct inode *inode);
+
+#else
+static inline int integrity_inode_alloc(struct inode *inode)
+{
+	return 0;
+}
+
+static inline void integrity_inode_free(struct inode *inode)
+{
+	return;
+}
+#endif /* CONFIG_INTEGRITY_H */
+#endif /* _LINUX_INTEGRITY_H */

security/Kconfig

@@ -186,7 +186,7 @@ source security/smack/Kconfig
 source security/tomoyo/Kconfig
 source security/apparmor/Kconfig
 
-source security/integrity/ima/Kconfig
+source security/integrity/Kconfig
 
 choice
 	prompt "Default security module"

security/Makefile

@@ -24,5 +24,5 @@ obj-$(CONFIG_SECURITY_APPARMOR)		+= apparmor/built-in.o
 obj-$(CONFIG_CGROUP_DEVICE)		+= device_cgroup.o
 
 # Object integrity file lists
-subdir-$(CONFIG_IMA)			+= integrity/ima
-obj-$(CONFIG_IMA)			+= integrity/ima/built-in.o
+subdir-$(CONFIG_INTEGRITY)		+= integrity
+obj-$(CONFIG_INTEGRITY)			+= integrity/built-in.o

security/integrity/Kconfig

@@ -0,0 +1,6 @@
+#
+config INTEGRITY
+	def_bool y
+	depends on IMA
+
+source security/integrity/ima/Kconfig

security/integrity/Makefile

@@ -0,0 +1,10 @@
+#
+# Makefile for caching inode integrity data (iint)
+#
+
+obj-$(CONFIG_INTEGRITY) += integrity.o
+
+integrity-y := iint.o
+
+subdir-$(CONFIG_IMA)			+= ima
+obj-$(CONFIG_IMA)			+= ima/built-in.o

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);

security/integrity/ima/Kconfig

@@ -3,6 +3,7 @@
 config IMA
 	bool "Integrity Measurement Architecture(IMA)"
 	depends on SECURITY
+	select INTEGRITY
 	select SECURITYFS
 	select CRYPTO
 	select CRYPTO_HMAC

security/integrity/ima/Makefile

@@ -6,4 +6,4 @@
 obj-$(CONFIG_IMA) += ima.o
 
 ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
-	 ima_policy.o ima_iint.o ima_audit.o
+	 ima_policy.o ima_audit.o

security/integrity/ima/ima.h

@@ -24,11 +24,13 @@
 #include <linux/tpm.h>
 #include <linux/audit.h>
 
+#include "../integrity.h"
+
 enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_ASCII };
 enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
 
 /* digest size for IMA, fits SHA1 or MD5 */
-#define IMA_DIGEST_SIZE		20
+#define IMA_DIGEST_SIZE		SHA1_DIGEST_SIZE
 #define IMA_EVENT_NAME_LEN_MAX	255
 
 #define IMA_HASH_BITS 9
@@ -96,34 +98,21 @@ static inline unsigned long ima_hash_key(u8 *digest)
 	return hash_long(*digest, IMA_HASH_BITS);
 }
 
-/* iint cache flags */
-#define IMA_MEASURED		0x01
-
-/* integrity data associated with an inode */
-struct ima_iint_cache {
-	struct rb_node rb_node; /* rooted in ima_iint_tree */
-	struct inode *inode;	/* back pointer to inode in question */
-	u64 version;		/* track inode changes */
-	unsigned char flags;
-	u8 digest[IMA_DIGEST_SIZE];
-	struct mutex mutex;	/* protects: version, flags, digest */
-};
-
 /* LIM API function definitions */
 int ima_must_measure(struct inode *inode, int mask, int function);
-int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file);
-void ima_store_measurement(struct ima_iint_cache *iint, struct file *file,
+int ima_collect_measurement(struct integrity_iint_cache *iint,
+			    struct file *file);
+void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
 			   const unsigned char *filename);
 int ima_store_template(struct ima_template_entry *entry, int violation,
 		       struct inode *inode);
-void ima_template_show(struct seq_file *m, void *e,
-		       enum ima_show_type show);
+void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show);
 
 /* rbtree tree calls to lookup, insert, delete
  * integrity data associated with an inode.
  */
-struct ima_iint_cache *ima_iint_insert(struct inode *inode);
-struct ima_iint_cache *ima_iint_find(struct inode *inode);
+struct integrity_iint_cache *integrity_iint_insert(struct inode *inode);
+struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
 
 /* IMA policy related functions */
 enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK };

security/integrity/ima/ima_api.c

@@ -126,7 +126,8 @@ int ima_must_measure(struct inode *inode, int mask, int function)
  *
  * Return 0 on success, error code otherwise
  */
-int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file)
+int ima_collect_measurement(struct integrity_iint_cache *iint,
+			    struct file *file)
 {
 	int result = -EEXIST;
 
@@ -156,8 +157,8 @@ int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file)
  *
  * Must be called with iint->mutex held.
  */
-void ima_store_measurement(struct ima_iint_cache *iint, struct file *file,
-			   const unsigned char *filename)
+void ima_store_measurement(struct integrity_iint_cache *iint,
+			   struct file *file, const unsigned char *filename)
 {
 	const char *op = "add_template_measure";
 	const char *audit_cause = "ENOMEM";