Linux-libre 4.5-gnu

8 files changed, 431 insertions, 57 deletions

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index df3033460..e54a8a8da 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -107,6 +107,27 @@ config IMA_DEFAULT_HASH
 	default "sha512" if IMA_DEFAULT_HASH_SHA512
 	default "wp512" if IMA_DEFAULT_HASH_WP512
 
+config IMA_WRITE_POLICY
+	bool "Enable multiple writes to the IMA policy"
+	depends on IMA
+	default n
+	help
+	  IMA policy can now be updated multiple times.  The new rules get
+	  appended to the original policy.  Have in mind that the rules are
+	  scanned in FIFO order so be careful when you design and add new ones.
+
+	  If unsure, say N.
+
+config IMA_READ_POLICY
+	bool "Enable reading back the current IMA policy"
+	depends on IMA
+	default y if IMA_WRITE_POLICY
+	default n if !IMA_WRITE_POLICY
+	help
+	   It is often useful to be able to read back the IMA policy.  It is
+	   even more important after introducing CONFIG_IMA_WRITE_POLICY.
+	   This option allows the root user to see the current policy rules.
+
 config IMA_APPRAISE
 	bool "Appraise integrity measurements"
 	depends on IMA
@@ -123,14 +144,35 @@ config IMA_APPRAISE
 	  If unsure, say N.
 
 config IMA_TRUSTED_KEYRING
-	bool "Require all keys on the .ima keyring be signed"
+	bool "Require all keys on the .ima keyring be signed (deprecated)"
 	depends on IMA_APPRAISE && SYSTEM_TRUSTED_KEYRING
 	depends on INTEGRITY_ASYMMETRIC_KEYS
+	select INTEGRITY_TRUSTED_KEYRING
 	default y
 	help
 	   This option requires that all keys added to the .ima
 	   keyring be signed by a key on the system trusted keyring.
 
+	   This option is deprecated in favor of INTEGRITY_TRUSTED_KEYRING
+
+config IMA_MOK_KEYRING
+	bool "Create IMA machine owner keys (MOK) and blacklist keyrings"
+	depends on SYSTEM_TRUSTED_KEYRING
+	depends on IMA_TRUSTED_KEYRING
+	default n
+	help
+	   This option creates IMA MOK and blacklist keyrings.  IMA MOK is an
+	   intermediate keyring that sits between .system and .ima keyrings,
+	   effectively forming a simple CA hierarchy.  To successfully import a
+	   key into .ima_mok it must be signed by a key which CA is in .system
+	   keyring.  On turn any key that needs to go in .ima keyring must be
+	   signed by CA in either .system or .ima_mok keyrings. IMA MOK is empty
+	   at kernel boot.
+
+	   IMA blacklist keyring contains all revoked IMA keys.  It is consulted
+	   before any other keyring.  If the search is successful the requested
+	   operation is rejected and error is returned to the caller.
+
 config IMA_LOAD_X509
 	bool "Load X509 certificate onto the '.ima' trusted keyring"
 	depends on IMA_TRUSTED_KEYRING
diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index d79263d2f..a8539f9e0 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_IMA) += ima.o
 ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
 	 ima_policy.o ima_template.o ima_template_lib.o
 ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
+obj-$(CONFIG_IMA_MOK_KEYRING) += ima_mok.o
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index e2a60c30d..585af61ed 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -166,6 +166,11 @@ void ima_update_policy(void);
 void ima_update_policy_flag(void);
 ssize_t ima_parse_add_rule(char *);
 void ima_delete_rules(void);
+int ima_check_policy(void);
+void *ima_policy_start(struct seq_file *m, loff_t *pos);
+void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos);
+void ima_policy_stop(struct seq_file *m, void *v);
+int ima_policy_show(struct seq_file *m, void *v);
 
 /* Appraise integrity measurements */
 #define IMA_APPRAISE_ENFORCE	0x01
@@ -250,17 +255,12 @@ static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
 {
 	return -EINVAL;
 }
-#endif /* CONFIG_IMA_LSM_RULES */
+#endif /* CONFIG_IMA_TRUSTED_KEYRING */
 
-#ifdef CONFIG_IMA_TRUSTED_KEYRING
-static inline int ima_init_keyring(const unsigned int id)
-{
-	return integrity_init_keyring(id);
-}
+#ifdef	CONFIG_IMA_READ_POLICY
+#define	POLICY_FILE_FLAGS	(S_IWUSR | S_IRUSR)
 #else
-static inline int ima_init_keyring(const unsigned int id)
-{
-	return 0;
-}
-#endif /* CONFIG_IMA_TRUSTED_KEYRING */
-#endif
+#define	POLICY_FILE_FLAGS	S_IWUSR
+#endif /* CONFIG_IMA_WRITE_POLICY */
+
+#endif /* __LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 816d175da..f35523199 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -25,6 +25,8 @@
 
 #include "ima.h"
 
+static DEFINE_MUTEX(ima_write_mutex);
+
 static int valid_policy = 1;
 #define TMPBUFLEN 12
 static ssize_t ima_show_htable_value(char __user *buf, size_t count,
@@ -259,7 +261,7 @@ static const struct file_operations ima_ascii_measurements_ops = {
 static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 				size_t datalen, loff_t *ppos)
 {
-	char *data = NULL;
+	char *data;
 	ssize_t result;
 
 	if (datalen >= PAGE_SIZE)
@@ -279,13 +281,20 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 
 	result = -EFAULT;
 	if (copy_from_user(data, buf, datalen))
-		goto out;
+		goto out_free;
 
+	result = mutex_lock_interruptible(&ima_write_mutex);
+	if (result < 0)
+		goto out_free;
 	result = ima_parse_add_rule(data);
+	mutex_unlock(&ima_write_mutex);
+
+out_free:
+	kfree(data);
 out:
 	if (result < 0)
 		valid_policy = 0;
-	kfree(data);
+
 	return result;
 }
 
@@ -302,14 +311,31 @@ enum ima_fs_flags {
 
 static unsigned long ima_fs_flags;
 
+#ifdef	CONFIG_IMA_READ_POLICY
+static const struct seq_operations ima_policy_seqops = {
+		.start = ima_policy_start,
+		.next = ima_policy_next,
+		.stop = ima_policy_stop,
+		.show = ima_policy_show,
+};
+#endif
+
 /*
  * ima_open_policy: sequentialize access to the policy file
  */
 static int ima_open_policy(struct inode *inode, struct file *filp)
 {
-	/* No point in being allowed to open it if you aren't going to write */
-	if (!(filp->f_flags & O_WRONLY))
+	if (!(filp->f_flags & O_WRONLY)) {
+#ifndef	CONFIG_IMA_READ_POLICY
 		return -EACCES;
+#else
+		if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
+			return -EACCES;
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		return seq_open(filp, &ima_policy_seqops);
+#endif
+	}
 	if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags))
 		return -EBUSY;
 	return 0;
@@ -326,6 +352,14 @@ static int ima_release_policy(struct inode *inode, struct file *file)
 {
 	const char *cause = valid_policy ? "completed" : "failed";
 
+	if ((file->f_flags & O_ACCMODE) == O_RDONLY)
+		return 0;
+
+	if (valid_policy && ima_check_policy() < 0) {
+		cause = "failed";
+		valid_policy = 0;
+	}
+
 	pr_info("IMA: policy update %s\n", cause);
 	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
 			    "policy_update", cause, !valid_policy, 0);
@@ -336,15 +370,21 @@ static int ima_release_policy(struct inode *inode, struct file *file)
 		clear_bit(IMA_FS_BUSY, &ima_fs_flags);
 		return 0;
 	}
+
 	ima_update_policy();
+#ifndef	CONFIG_IMA_WRITE_POLICY
 	securityfs_remove(ima_policy);
 	ima_policy = NULL;
+#else
+	clear_bit(IMA_FS_BUSY, &ima_fs_flags);
+#endif
 	return 0;
 }
 
 static const struct file_operations ima_measure_policy_ops = {
 	.open = ima_open_policy,
 	.write = ima_write_policy,
+	.read = seq_read,
 	.release = ima_release_policy,
 	.llseek = generic_file_llseek,
 };
@@ -382,8 +422,7 @@ int __init ima_fs_init(void)
 	if (IS_ERR(violations))
 		goto out;
 
-	ima_policy = securityfs_create_file("policy",
-					    S_IWUSR,
+	ima_policy = securityfs_create_file("policy", POLICY_FILE_FLAGS,
 					    ima_dir, NULL,
 					    &ima_measure_policy_ops);
 	if (IS_ERR(ima_policy))
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index e600cadd2..bd79f254d 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -116,7 +116,7 @@ int __init ima_init(void)
 	if (!ima_used_chip)
 		pr_info("No TPM chip found, activating TPM-bypass!\n");
 
-	rc = ima_init_keyring(INTEGRITY_KEYRING_IMA);
+	rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
 	if (rc)
 		return rc;
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index c21f09bf8..9d96551d0 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -121,7 +121,7 @@ static void ima_check_last_writer(struct integrity_iint_cache *iint,
 	if (!(mode & FMODE_WRITE))
 		return;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 	if (atomic_read(&inode->i_writecount) == 1) {
 		if ((iint->version != inode->i_version) ||
 		    (iint->flags & IMA_NEW_FILE)) {
@@ -130,7 +130,7 @@ static void ima_check_last_writer(struct integrity_iint_cache *iint,
 				ima_update_xattr(iint, file);
 		}
 	}
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 }
 
 /**
@@ -186,7 +186,7 @@ static int process_measurement(struct file *file, int mask, int function,
 	if (action & IMA_FILE_APPRAISE)
 		function = FILE_CHECK;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 
 	if (action) {
 		iint = integrity_inode_get(inode);
@@ -250,7 +250,7 @@ out_free:
 	if (pathbuf)
 		__putname(pathbuf);
 out:
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 	if ((rc && must_appraise) && (ima_appraise & IMA_APPRAISE_ENFORCE))
 		return -EACCES;
 	return 0;
diff --git a/security/integrity/ima/ima_mok.c b/security/integrity/ima/ima_mok.c
new file mode 100644
index 000000000..676885e43
--- /dev/null
+++ b/security/integrity/ima/ima_mok.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2015 Juniper Networks, Inc.
+ *
+ * Author:
+ * Petko Manolov <petko.manolov@konsulko.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.
+ *
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <keys/asymmetric-type.h>
+
+
+struct key *ima_mok_keyring;
+struct key *ima_blacklist_keyring;
+
+/*
+ * Allocate the IMA MOK and blacklist keyrings
+ */
+__init int ima_mok_init(void)
+{
+	pr_notice("Allocating IMA MOK and blacklist keyrings.\n");
+
+	ima_mok_keyring = keyring_alloc(".ima_mok",
+			      KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
+			      (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+			      KEY_USR_VIEW | KEY_USR_READ |
+			      KEY_USR_WRITE | KEY_USR_SEARCH,
+			      KEY_ALLOC_NOT_IN_QUOTA, NULL);
+
+	ima_blacklist_keyring = keyring_alloc(".ima_blacklist",
+				KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
+				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
+				KEY_USR_VIEW | KEY_USR_READ |
+				KEY_USR_WRITE | KEY_USR_SEARCH,
+				KEY_ALLOC_NOT_IN_QUOTA, NULL);
+
+	if (IS_ERR(ima_mok_keyring) || IS_ERR(ima_blacklist_keyring))
+		panic("Can't allocate IMA MOK or blacklist keyrings.");
+	set_bit(KEY_FLAG_TRUSTED_ONLY, &ima_mok_keyring->flags);
+
+	set_bit(KEY_FLAG_TRUSTED_ONLY, &ima_blacklist_keyring->flags);
+	set_bit(KEY_FLAG_KEEP, &ima_blacklist_keyring->flags);
+	return 0;
+}
+device_initcall(ima_mok_init);
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 3997e206f..0a3b781f1 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -16,7 +16,9 @@
 #include <linux/magic.h>
 #include <linux/parser.h>
 #include <linux/slab.h>
+#include <linux/rculist.h>
 #include <linux/genhd.h>
+#include <linux/seq_file.h>
 
 #include "ima.h"
 
@@ -38,6 +40,7 @@
 #define AUDIT		0x0040
 
 int ima_policy_flag;
+static int temp_ima_appraise;
 
 #define MAX_LSM_RULES 6
 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
@@ -135,11 +138,11 @@ static struct ima_rule_entry default_appraise_rules[] = {
 
 static LIST_HEAD(ima_default_rules);
 static LIST_HEAD(ima_policy_rules);
+static LIST_HEAD(ima_temp_rules);
 static struct list_head *ima_rules;
 
-static DEFINE_MUTEX(ima_rules_mutex);
-
 static int ima_policy __initdata;
+
 static int __init default_measure_policy_setup(char *str)
 {
 	if (ima_policy)
@@ -171,21 +174,18 @@ static int __init default_appraise_policy_setup(char *str)
 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 
 /*
- * Although the IMA policy does not change, the LSM policy can be
- * reloaded, leaving the IMA LSM based rules referring to the old,
- * stale LSM policy.
- *
- * Update the IMA LSM based rules to reflect the reloaded LSM policy.
- * We assume the rules still exist; and BUG_ON() if they don't.
+ * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
+ * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
+ * the reloaded LSM policy.  We assume the rules still exist; and BUG_ON() if
+ * they don't.
  */
 static void ima_lsm_update_rules(void)
 {
-	struct ima_rule_entry *entry, *tmp;
+	struct ima_rule_entry *entry;
 	int result;
 	int i;
 
-	mutex_lock(&ima_rules_mutex);
-	list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
+	list_for_each_entry(entry, &ima_policy_rules, list) {
 		for (i = 0; i < MAX_LSM_RULES; i++) {
 			if (!entry->lsm[i].rule)
 				continue;
@@ -196,7 +196,6 @@ static void ima_lsm_update_rules(void)
 			BUG_ON(!entry->lsm[i].rule);
 		}
 	}
-	mutex_unlock(&ima_rules_mutex);
 }
 
 /**
@@ -319,9 +318,9 @@ static int get_subaction(struct ima_rule_entry *rule, int func)
  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
  * conditions.
  *
- * (There is no need for locking when walking the policy list,
- * as elements in the list are never deleted, nor does the list
- * change.)
+ * Since the IMA policy may be updated multiple times we need to lock the
+ * list when walking it.  Reads are many orders of magnitude more numerous
+ * than writes so ima_match_policy() is classical RCU candidate.
  */
 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 		     int flags)
@@ -329,7 +328,8 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 	struct ima_rule_entry *entry;
 	int action = 0, actmask = flags | (flags << 1);
 
-	list_for_each_entry(entry, ima_rules, list) {
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, ima_rules, list) {
 
 		if (!(entry->action & actmask))
 			continue;
@@ -351,6 +351,7 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 		if (!actmask)
 			break;
 	}
+	rcu_read_unlock();
 
 	return action;
 }
@@ -365,12 +366,12 @@ void ima_update_policy_flag(void)
 {
 	struct ima_rule_entry *entry;
 
-	ima_policy_flag = 0;
 	list_for_each_entry(entry, ima_rules, list) {
 		if (entry->action & IMA_DO_MASK)
 			ima_policy_flag |= entry->action;
 	}
 
+	ima_appraise |= temp_ima_appraise;
 	if (!ima_appraise)
 		ima_policy_flag &= ~IMA_APPRAISE;
 }
@@ -415,16 +416,48 @@ void __init ima_init_policy(void)
 	ima_rules = &ima_default_rules;
 }
 
+/* Make sure we have a valid policy, at least containing some rules. */
+int ima_check_policy()
+{
+	if (list_empty(&ima_temp_rules))
+		return -EINVAL;
+	return 0;
+}
+
 /**
  * ima_update_policy - update default_rules with new measure rules
  *
  * Called on file .release to update the default rules with a complete new
- * policy.  Once updated, the policy is locked, no additional rules can be
- * added to the policy.
+ * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
+ * they make a queue.  The policy may be updated multiple times and this is the
+ * RCU updater.
+ *
+ * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
+ * we switch from the default policy to user defined.
  */
 void ima_update_policy(void)
 {
-	ima_rules = &ima_policy_rules;
+	struct list_head *first, *last, *policy;
+
+	/* append current policy with the new rules */
+	first = (&ima_temp_rules)->next;
+	last = (&ima_temp_rules)->prev;
+	policy = &ima_policy_rules;
+
+	synchronize_rcu();
+
+	last->next = policy;
+	rcu_assign_pointer(list_next_rcu(policy->prev), first);
+	first->prev = policy->prev;
+	policy->prev = last;
+
+	/* prepare for the next policy rules addition */
+	INIT_LIST_HEAD(&ima_temp_rules);
+
+	if (ima_rules != policy) {
+		ima_policy_flag = 0;
+		ima_rules = policy;
+	}
 	ima_update_policy_flag();
 }
 
@@ -436,8 +469,8 @@ enum {
 	Opt_obj_user, Opt_obj_role, Opt_obj_type,
 	Opt_subj_user, Opt_subj_role, Opt_subj_type,
 	Opt_func, Opt_mask, Opt_fsmagic,
-	Opt_uid, Opt_euid, Opt_fowner,
-	Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
+	Opt_fsuuid, Opt_uid, Opt_euid, Opt_fowner,
+	Opt_appraise_type, Opt_permit_directio
 };
 
 static match_table_t policy_tokens = {
@@ -734,9 +767,9 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 	if (!result && (entry->action == UNKNOWN))
 		result = -EINVAL;
 	else if (entry->func == MODULE_CHECK)
-		ima_appraise |= IMA_APPRAISE_MODULES;
+		temp_ima_appraise |= IMA_APPRAISE_MODULES;
 	else if (entry->func == FIRMWARE_CHECK)
-		ima_appraise |= IMA_APPRAISE_FIRMWARE;
+		temp_ima_appraise |= IMA_APPRAISE_FIRMWARE;
 	audit_log_format(ab, "res=%d", !result);
 	audit_log_end(ab);
 	return result;
@@ -746,7 +779,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
  * ima_parse_add_rule - add a rule to ima_policy_rules
  * @rule - ima measurement policy rule
  *
- * Uses a mutex to protect the policy list from multiple concurrent writers.
+ * Avoid locking by allowing just one writer at a time in ima_write_policy()
  * Returns the length of the rule parsed, an error code on failure
  */
 ssize_t ima_parse_add_rule(char *rule)
@@ -782,26 +815,230 @@ ssize_t ima_parse_add_rule(char *rule)
 		return result;
 	}
 
-	mutex_lock(&ima_rules_mutex);
-	list_add_tail(&entry->list, &ima_policy_rules);
-	mutex_unlock(&ima_rules_mutex);
+	list_add_tail(&entry->list, &ima_temp_rules);
 
 	return len;
 }
 
-/* ima_delete_rules called to cleanup invalid policy */
+/**
+ * ima_delete_rules() called to cleanup invalid in-flight policy.
+ * We don't need locking as we operate on the temp list, which is
+ * different from the active one.  There is also only one user of
+ * ima_delete_rules() at a time.
+ */
 void ima_delete_rules(void)
 {
 	struct ima_rule_entry *entry, *tmp;
 	int i;
 
-	mutex_lock(&ima_rules_mutex);
-	list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
+	temp_ima_appraise = 0;
+	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
 		for (i = 0; i < MAX_LSM_RULES; i++)
 			kfree(entry->lsm[i].args_p);
 
 		list_del(&entry->list);
 		kfree(entry);
 	}
-	mutex_unlock(&ima_rules_mutex);
 }
+
+#ifdef	CONFIG_IMA_READ_POLICY
+enum {
+	mask_exec = 0, mask_write, mask_read, mask_append
+};
+
+static char *mask_tokens[] = {
+	"MAY_EXEC",
+	"MAY_WRITE",
+	"MAY_READ",
+	"MAY_APPEND"
+};
+
+enum {
+	func_file = 0, func_mmap, func_bprm,
+	func_module, func_firmware, func_post
+};
+
+static char *func_tokens[] = {
+	"FILE_CHECK",
+	"MMAP_CHECK",
+	"BPRM_CHECK",
+	"MODULE_CHECK",
+	"FIRMWARE_CHECK",
+	"POST_SETATTR"
+};
+
+void *ima_policy_start(struct seq_file *m, loff_t *pos)
+{
+	loff_t l = *pos;
+	struct ima_rule_entry *entry;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, ima_rules, list) {
+		if (!l--) {
+			rcu_read_unlock();
+			return entry;
+		}
+	}
+	rcu_read_unlock();
+	return NULL;
+}
+
+void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct ima_rule_entry *entry = v;
+
+	rcu_read_lock();
+	entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
+	rcu_read_unlock();
+	(*pos)++;
+
+	return (&entry->list == ima_rules) ? NULL : entry;
+}
+
+void ima_policy_stop(struct seq_file *m, void *v)
+{
+}
+
+#define pt(token)	policy_tokens[token + Opt_err].pattern
+#define mt(token)	mask_tokens[token]
+#define ft(token)	func_tokens[token]
+
+int ima_policy_show(struct seq_file *m, void *v)
+{
+	struct ima_rule_entry *entry = v;
+	int i = 0;
+	char tbuf[64] = {0,};
+
+	rcu_read_lock();
+
+	if (entry->action & MEASURE)
+		seq_puts(m, pt(Opt_measure));
+	if (entry->action & DONT_MEASURE)
+		seq_puts(m, pt(Opt_dont_measure));
+	if (entry->action & APPRAISE)
+		seq_puts(m, pt(Opt_appraise));
+	if (entry->action & DONT_APPRAISE)
+		seq_puts(m, pt(Opt_dont_appraise));
+	if (entry->action & AUDIT)
+		seq_puts(m, pt(Opt_audit));
+
+	seq_puts(m, " ");
+
+	if (entry->flags & IMA_FUNC) {
+		switch (entry->func) {
+		case FILE_CHECK:
+			seq_printf(m, pt(Opt_func), ft(func_file));
+			break;
+		case MMAP_CHECK:
+			seq_printf(m, pt(Opt_func), ft(func_mmap));
+			break;
+		case BPRM_CHECK:
+			seq_printf(m, pt(Opt_func), ft(func_bprm));
+			break;
+		case MODULE_CHECK:
+			seq_printf(m, pt(Opt_func), ft(func_module));
+			break;
+		case FIRMWARE_CHECK:
+			seq_printf(m, pt(Opt_func), ft(func_firmware));
+			break;
+		case POST_SETATTR:
+			seq_printf(m, pt(Opt_func), ft(func_post));
+			break;
+		default:
+			snprintf(tbuf, sizeof(tbuf), "%d", entry->func);
+			seq_printf(m, pt(Opt_func), tbuf);
+			break;
+		}
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_MASK) {
+		if (entry->mask & MAY_EXEC)
+			seq_printf(m, pt(Opt_mask), mt(mask_exec));
+		if (entry->mask & MAY_WRITE)
+			seq_printf(m, pt(Opt_mask), mt(mask_write));
+		if (entry->mask & MAY_READ)
+			seq_printf(m, pt(Opt_mask), mt(mask_read));
+		if (entry->mask & MAY_APPEND)
+			seq_printf(m, pt(Opt_mask), mt(mask_append));
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_FSMAGIC) {
+		snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
+		seq_printf(m, pt(Opt_fsmagic), tbuf);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_FSUUID) {
+		seq_puts(m, "fsuuid=");
+		for (i = 0; i < ARRAY_SIZE(entry->fsuuid); ++i) {
+			switch (i) {
+			case 4:
+			case 6:
+			case 8:
+			case 10:
+				seq_puts(m, "-");
+			}
+			seq_printf(m, "%x", entry->fsuuid[i]);
+		}
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_UID) {
+		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+		seq_printf(m, pt(Opt_uid), tbuf);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_EUID) {
+		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+		seq_printf(m, pt(Opt_euid), tbuf);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_FOWNER) {
+		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
+		seq_printf(m, pt(Opt_fowner), tbuf);
+		seq_puts(m, " ");
+	}
+
+	for (i = 0; i < MAX_LSM_RULES; i++) {
+		if (entry->lsm[i].rule) {
+			switch (i) {
+			case LSM_OBJ_USER:
+				seq_printf(m, pt(Opt_obj_user),
+					   (char *)entry->lsm[i].args_p);
+				break;
+			case LSM_OBJ_ROLE:
+				seq_printf(m, pt(Opt_obj_role),
+					   (char *)entry->lsm[i].args_p);
+				break;
+			case LSM_OBJ_TYPE:
+				seq_printf(m, pt(Opt_obj_type),
+					   (char *)entry->lsm[i].args_p);
+				break;
+			case LSM_SUBJ_USER:
+				seq_printf(m, pt(Opt_subj_user),
+					   (char *)entry->lsm[i].args_p);
+				break;
+			case LSM_SUBJ_ROLE:
+				seq_printf(m, pt(Opt_subj_role),
+					   (char *)entry->lsm[i].args_p);
+				break;
+			case LSM_SUBJ_TYPE:
+				seq_printf(m, pt(Opt_subj_type),
+					   (char *)entry->lsm[i].args_p);
+				break;
+			}
+		}
+	}
+	if (entry->flags & IMA_DIGSIG_REQUIRED)
+		seq_puts(m, "appraise_type=imasig ");
+	if (entry->flags & IMA_PERMIT_DIRECTIO)
+		seq_puts(m, "permit_directio ");
+	rcu_read_unlock();
+	seq_puts(m, "\n");
+	return 0;
+}
+#endif	/* CONFIG_IMA_READ_POLICY */