Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1866 insertions, 0 deletions

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
new file mode 100644
index 000000000..1c403e8a8
--- /dev/null
+++ b/security/integrity/ima/ima_policy.c
@@ -0,0 +1,1866 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2008 IBM Corporation
+ * Author: Mimi Zohar <zohar@us.ibm.com>
+ *
+ * ima_policy.c
+ *	- initialize default measure policy rules
+ */
+
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/kernel_read_file.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#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 <linux/ima.h>
+
+#include "ima.h"
+
+/* flags definitions */
+#define IMA_FUNC	0x0001
+#define IMA_MASK	0x0002
+#define IMA_FSMAGIC	0x0004
+#define IMA_UID		0x0008
+#define IMA_FOWNER	0x0010
+#define IMA_FSUUID	0x0020
+#define IMA_INMASK	0x0040
+#define IMA_EUID	0x0080
+#define IMA_PCR		0x0100
+#define IMA_FSNAME	0x0200
+#define IMA_KEYRINGS	0x0400
+
+#define UNKNOWN		0
+#define MEASURE		0x0001	/* same as IMA_MEASURE */
+#define DONT_MEASURE	0x0002
+#define APPRAISE	0x0004	/* same as IMA_APPRAISE */
+#define DONT_APPRAISE	0x0008
+#define AUDIT		0x0040
+#define HASH		0x0100
+#define DONT_HASH	0x0200
+
+#define INVALID_PCR(a) (((a) < 0) || \
+	(a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
+
+int ima_policy_flag;
+static int temp_ima_appraise;
+static int build_ima_appraise __ro_after_init;
+
+#define MAX_LSM_RULES 6
+enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
+	LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
+};
+
+enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
+
+enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
+
+struct ima_rule_opt_list {
+	size_t count;
+	char *items[];
+};
+
+struct ima_rule_entry {
+	struct list_head list;
+	int action;
+	unsigned int flags;
+	enum ima_hooks func;
+	int mask;
+	unsigned long fsmagic;
+	uuid_t fsuuid;
+	kuid_t uid;
+	kuid_t fowner;
+	bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
+	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
+	int pcr;
+	struct {
+		void *rule;	/* LSM file metadata specific */
+		char *args_p;	/* audit value */
+		int type;	/* audit type */
+	} lsm[MAX_LSM_RULES];
+	char *fsname;
+	struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
+	struct ima_template_desc *template;
+};
+
+/*
+ * Without LSM specific knowledge, the default policy can only be
+ * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
+ */
+
+/*
+ * The minimum rule set to allow for full TCB coverage.  Measures all files
+ * opened or mmap for exec and everything read by root.  Dangerous because
+ * normal users can easily run the machine out of memory simply building
+ * and running executables.
+ */
+static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
+	{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
+	 .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
+	 .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
+};
+
+static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
+	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
+	 .flags = IMA_FUNC | IMA_MASK},
+	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
+	 .flags = IMA_FUNC | IMA_MASK},
+	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
+	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
+	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
+	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
+	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
+};
+
+static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
+	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
+	 .flags = IMA_FUNC | IMA_MASK},
+	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
+	 .flags = IMA_FUNC | IMA_MASK},
+	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
+	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
+	 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
+	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
+	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
+	 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
+	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
+	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
+	{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
+};
+
+static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
+	{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+#ifdef CONFIG_IMA_WRITE_POLICY
+	{.action = APPRAISE, .func = POLICY_CHECK,
+	.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
+	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
+	 .flags = IMA_FOWNER},
+#else
+	/* force signature */
+	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
+	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
+#endif
+};
+
+static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
+	{.action = APPRAISE, .func = MODULE_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
+	{.action = APPRAISE, .func = FIRMWARE_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
+	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
+	{.action = APPRAISE, .func = POLICY_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+};
+
+static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
+	{.action = APPRAISE, .func = MODULE_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+	{.action = APPRAISE, .func = FIRMWARE_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+	{.action = APPRAISE, .func = POLICY_CHECK,
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+};
+
+/* An array of architecture specific rules */
+static struct ima_rule_entry *arch_policy_entry __ro_after_init;
+
+static LIST_HEAD(ima_default_rules);
+static LIST_HEAD(ima_policy_rules);
+static LIST_HEAD(ima_temp_rules);
+static struct list_head *ima_rules = &ima_default_rules;
+
+static int ima_policy __initdata;
+
+static int __init default_measure_policy_setup(char *str)
+{
+	if (ima_policy)
+		return 1;
+
+	ima_policy = ORIGINAL_TCB;
+	return 1;
+}
+__setup("ima_tcb", default_measure_policy_setup);
+
+static bool ima_use_appraise_tcb __initdata;
+static bool ima_use_secure_boot __initdata;
+static bool ima_fail_unverifiable_sigs __ro_after_init;
+static int __init policy_setup(char *str)
+{
+	char *p;
+
+	while ((p = strsep(&str, " |\n")) != NULL) {
+		if (*p == ' ')
+			continue;
+		if ((strcmp(p, "tcb") == 0) && !ima_policy)
+			ima_policy = DEFAULT_TCB;
+		else if (strcmp(p, "appraise_tcb") == 0)
+			ima_use_appraise_tcb = true;
+		else if (strcmp(p, "secure_boot") == 0)
+			ima_use_secure_boot = true;
+		else if (strcmp(p, "fail_securely") == 0)
+			ima_fail_unverifiable_sigs = true;
+		else
+			pr_err("policy \"%s\" not found", p);
+	}
+
+	return 1;
+}
+__setup("ima_policy=", policy_setup);
+
+static int __init default_appraise_policy_setup(char *str)
+{
+	ima_use_appraise_tcb = true;
+	return 1;
+}
+__setup("ima_appraise_tcb", default_appraise_policy_setup);
+
+static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
+{
+	struct ima_rule_opt_list *opt_list;
+	size_t count = 0;
+	char *src_copy;
+	char *cur, *next;
+	size_t i;
+
+	src_copy = match_strdup(src);
+	if (!src_copy)
+		return ERR_PTR(-ENOMEM);
+
+	next = src_copy;
+	while ((cur = strsep(&next, "|"))) {
+		/* Don't accept an empty list item */
+		if (!(*cur)) {
+			kfree(src_copy);
+			return ERR_PTR(-EINVAL);
+		}
+		count++;
+	}
+
+	/* Don't accept an empty list */
+	if (!count) {
+		kfree(src_copy);
+		return ERR_PTR(-EINVAL);
+	}
+
+	opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
+	if (!opt_list) {
+		kfree(src_copy);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/*
+	 * strsep() has already replaced all instances of '|' with '\0',
+	 * leaving a byte sequence of NUL-terminated strings. Reference each
+	 * string with the array of items.
+	 *
+	 * IMPORTANT: Ownership of the allocated buffer is transferred from
+	 * src_copy to the first element in the items array. To free the
+	 * buffer, kfree() must only be called on the first element of the
+	 * array.
+	 */
+	for (i = 0, cur = src_copy; i < count; i++) {
+		opt_list->items[i] = cur;
+		cur = strchr(cur, '\0') + 1;
+	}
+	opt_list->count = count;
+
+	return opt_list;
+}
+
+static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
+{
+	if (!opt_list)
+		return;
+
+	if (opt_list->count) {
+		kfree(opt_list->items[0]);
+		opt_list->count = 0;
+	}
+
+	kfree(opt_list);
+}
+
+static void ima_lsm_free_rule(struct ima_rule_entry *entry)
+{
+	int i;
+
+	for (i = 0; i < MAX_LSM_RULES; i++) {
+		ima_filter_rule_free(entry->lsm[i].rule);
+		kfree(entry->lsm[i].args_p);
+	}
+}
+
+static void ima_free_rule(struct ima_rule_entry *entry)
+{
+	if (!entry)
+		return;
+
+	/*
+	 * entry->template->fields may be allocated in ima_parse_rule() but that
+	 * reference is owned by the corresponding ima_template_desc element in
+	 * the defined_templates list and cannot be freed here
+	 */
+	kfree(entry->fsname);
+	ima_free_rule_opt_list(entry->keyrings);
+	ima_lsm_free_rule(entry);
+	kfree(entry);
+}
+
+static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
+{
+	struct ima_rule_entry *nentry;
+	int i;
+
+	/*
+	 * Immutable elements are copied over as pointers and data; only
+	 * lsm rules can change
+	 */
+	nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
+	if (!nentry)
+		return NULL;
+
+	memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
+
+	for (i = 0; i < MAX_LSM_RULES; i++) {
+		if (!entry->lsm[i].args_p)
+			continue;
+
+		nentry->lsm[i].type = entry->lsm[i].type;
+		nentry->lsm[i].args_p = entry->lsm[i].args_p;
+
+		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
+				     nentry->lsm[i].args_p,
+				     &nentry->lsm[i].rule);
+		if (!nentry->lsm[i].rule)
+			pr_warn("rule for LSM \'%s\' is undefined\n",
+				nentry->lsm[i].args_p);
+	}
+	return nentry;
+}
+
+static int ima_lsm_update_rule(struct ima_rule_entry *entry)
+{
+	int i;
+	struct ima_rule_entry *nentry;
+
+	nentry = ima_lsm_copy_rule(entry);
+	if (!nentry)
+		return -ENOMEM;
+
+	list_replace_rcu(&entry->list, &nentry->list);
+	synchronize_rcu();
+	/*
+	 * ima_lsm_copy_rule() shallow copied all references, except for the
+	 * LSM references, from entry to nentry so we only want to free the LSM
+	 * references and the entry itself. All other memory refrences will now
+	 * be owned by nentry.
+	 */
+	for (i = 0; i < MAX_LSM_RULES; i++)
+		ima_filter_rule_free(entry->lsm[i].rule);
+	kfree(entry);
+
+	return 0;
+}
+
+static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
+{
+	int i;
+
+	for (i = 0; i < MAX_LSM_RULES; i++)
+		if (entry->lsm[i].args_p)
+			return true;
+
+	return false;
+}
+
+/*
+ * 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.
+ */
+static void ima_lsm_update_rules(void)
+{
+	struct ima_rule_entry *entry, *e;
+	int result;
+
+	list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
+		if (!ima_rule_contains_lsm_cond(entry))
+			continue;
+
+		result = ima_lsm_update_rule(entry);
+		if (result) {
+			pr_err("lsm rule update error %d\n", result);
+			return;
+		}
+	}
+}
+
+int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
+			  void *lsm_data)
+{
+	if (event != LSM_POLICY_CHANGE)
+		return NOTIFY_DONE;
+
+	ima_lsm_update_rules();
+	return NOTIFY_OK;
+}
+
+/**
+ * ima_match_keyring - determine whether the keyring matches the measure rule
+ * @rule: a pointer to a rule
+ * @keyring: name of the keyring to match against the measure rule
+ * @cred: a pointer to a credentials structure for user validation
+ *
+ * Returns true if keyring matches one in the rule, false otherwise.
+ */
+static bool ima_match_keyring(struct ima_rule_entry *rule,
+			      const char *keyring, const struct cred *cred)
+{
+	bool matched = false;
+	size_t i;
+
+	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
+		return false;
+
+	if (!rule->keyrings)
+		return true;
+
+	if (!keyring)
+		return false;
+
+	for (i = 0; i < rule->keyrings->count; i++) {
+		if (!strcmp(rule->keyrings->items[i], keyring)) {
+			matched = true;
+			break;
+		}
+	}
+
+	return matched;
+}
+
+/**
+ * ima_match_rules - determine whether an inode matches the policy rule.
+ * @rule: a pointer to a rule
+ * @inode: a pointer to an inode
+ * @cred: a pointer to a credentials structure for user validation
+ * @secid: the secid of the task to be validated
+ * @func: LIM hook identifier
+ * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
+ * @keyring: keyring name to check in policy for KEY_CHECK func
+ *
+ * Returns true on rule match, false on failure.
+ */
+static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
+			    const struct cred *cred, u32 secid,
+			    enum ima_hooks func, int mask,
+			    const char *keyring)
+{
+	int i;
+	bool result = false;
+	struct ima_rule_entry *lsm_rule = rule;
+	bool rule_reinitialized = false;
+
+	if (func == KEY_CHECK) {
+		return (rule->flags & IMA_FUNC) && (rule->func == func) &&
+		       ima_match_keyring(rule, keyring, cred);
+	}
+	if ((rule->flags & IMA_FUNC) &&
+	    (rule->func != func && func != POST_SETATTR))
+		return false;
+	if ((rule->flags & IMA_MASK) &&
+	    (rule->mask != mask && func != POST_SETATTR))
+		return false;
+	if ((rule->flags & IMA_INMASK) &&
+	    (!(rule->mask & mask) && func != POST_SETATTR))
+		return false;
+	if ((rule->flags & IMA_FSMAGIC)
+	    && rule->fsmagic != inode->i_sb->s_magic)
+		return false;
+	if ((rule->flags & IMA_FSNAME)
+	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
+		return false;
+	if ((rule->flags & IMA_FSUUID) &&
+	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
+		return false;
+	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
+		return false;
+	if (rule->flags & IMA_EUID) {
+		if (has_capability_noaudit(current, CAP_SETUID)) {
+			if (!rule->uid_op(cred->euid, rule->uid)
+			    && !rule->uid_op(cred->suid, rule->uid)
+			    && !rule->uid_op(cred->uid, rule->uid))
+				return false;
+		} else if (!rule->uid_op(cred->euid, rule->uid))
+			return false;
+	}
+
+	if ((rule->flags & IMA_FOWNER) &&
+	    !rule->fowner_op(inode->i_uid, rule->fowner))
+		return false;
+	for (i = 0; i < MAX_LSM_RULES; i++) {
+		int rc = 0;
+		u32 osid;
+
+		if (!lsm_rule->lsm[i].rule) {
+			if (!lsm_rule->lsm[i].args_p)
+				continue;
+			else
+				return false;
+		}
+
+retry:
+		switch (i) {
+		case LSM_OBJ_USER:
+		case LSM_OBJ_ROLE:
+		case LSM_OBJ_TYPE:
+			security_inode_getsecid(inode, &osid);
+			rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type,
+						   Audit_equal,
+						   lsm_rule->lsm[i].rule);
+			break;
+		case LSM_SUBJ_USER:
+		case LSM_SUBJ_ROLE:
+		case LSM_SUBJ_TYPE:
+			rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
+						   Audit_equal,
+						   lsm_rule->lsm[i].rule);
+			break;
+		default:
+			break;
+		}
+
+		if (rc == -ESTALE && !rule_reinitialized) {
+			lsm_rule = ima_lsm_copy_rule(rule);
+			if (lsm_rule) {
+				rule_reinitialized = true;
+				goto retry;
+			}
+		}
+		if (!rc) {
+			result = false;
+			goto out;
+		}
+	}
+	result = true;
+
+out:
+	if (rule_reinitialized) {
+		for (i = 0; i < MAX_LSM_RULES; i++)
+			ima_filter_rule_free(lsm_rule->lsm[i].rule);
+		kfree(lsm_rule);
+	}
+	return result;
+}
+
+/*
+ * In addition to knowing that we need to appraise the file in general,
+ * we need to differentiate between calling hooks, for hook specific rules.
+ */
+static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
+{
+	if (!(rule->flags & IMA_FUNC))
+		return IMA_FILE_APPRAISE;
+
+	switch (func) {
+	case MMAP_CHECK:
+		return IMA_MMAP_APPRAISE;
+	case BPRM_CHECK:
+		return IMA_BPRM_APPRAISE;
+	case CREDS_CHECK:
+		return IMA_CREDS_APPRAISE;
+	case FILE_CHECK:
+	case POST_SETATTR:
+		return IMA_FILE_APPRAISE;
+	case MODULE_CHECK ... MAX_CHECK - 1:
+	default:
+		return IMA_READ_APPRAISE;
+	}
+}
+
+/**
+ * ima_match_policy - decision based on LSM and other conditions
+ * @inode: pointer to an inode for which the policy decision is being made
+ * @cred: pointer to a credentials structure for which the policy decision is
+ *        being made
+ * @secid: LSM secid of the task to be validated
+ * @func: IMA hook identifier
+ * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
+ * @flags: IMA actions to consider (e.g. IMA_MEASURE | IMA_APPRAISE)
+ * @pcr: set the pcr to extend
+ * @template_desc: the template that should be used for this rule
+ * @keyring: the keyring name, if given, to be used to check in the policy.
+ *           keyring can be NULL if func is anything other than KEY_CHECK.
+ *
+ * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
+ * conditions.
+ *
+ * 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, const struct cred *cred, u32 secid,
+		     enum ima_hooks func, int mask, int flags, int *pcr,
+		     struct ima_template_desc **template_desc,
+		     const char *keyring)
+{
+	struct ima_rule_entry *entry;
+	int action = 0, actmask = flags | (flags << 1);
+
+	if (template_desc)
+		*template_desc = ima_template_desc_current();
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, ima_rules, list) {
+
+		if (!(entry->action & actmask))
+			continue;
+
+		if (!ima_match_rules(entry, inode, cred, secid, func, mask,
+				     keyring))
+			continue;
+
+		action |= entry->flags & IMA_ACTION_FLAGS;
+
+		action |= entry->action & IMA_DO_MASK;
+		if (entry->action & IMA_APPRAISE) {
+			action |= get_subaction(entry, func);
+			action &= ~IMA_HASH;
+			if (ima_fail_unverifiable_sigs)
+				action |= IMA_FAIL_UNVERIFIABLE_SIGS;
+		}
+
+
+		if (entry->action & IMA_DO_MASK)
+			actmask &= ~(entry->action | entry->action << 1);
+		else
+			actmask &= ~(entry->action | entry->action >> 1);
+
+		if ((pcr) && (entry->flags & IMA_PCR))
+			*pcr = entry->pcr;
+
+		if (template_desc && entry->template)
+			*template_desc = entry->template;
+
+		if (!actmask)
+			break;
+	}
+	rcu_read_unlock();
+
+	return action;
+}
+
+/*
+ * Initialize the ima_policy_flag variable based on the currently
+ * loaded policy.  Based on this flag, the decision to short circuit
+ * out of a function or not call the function in the first place
+ * can be made earlier.
+ */
+void ima_update_policy_flag(void)
+{
+	struct ima_rule_entry *entry;
+
+	list_for_each_entry(entry, ima_rules, list) {
+		if (entry->action & IMA_DO_MASK)
+			ima_policy_flag |= entry->action;
+	}
+
+	ima_appraise |= (build_ima_appraise | temp_ima_appraise);
+	if (!ima_appraise)
+		ima_policy_flag &= ~IMA_APPRAISE;
+}
+
+static int ima_appraise_flag(enum ima_hooks func)
+{
+	if (func == MODULE_CHECK)
+		return IMA_APPRAISE_MODULES;
+	else if (func == FIRMWARE_CHECK)
+		return IMA_APPRAISE_FIRMWARE;
+	else if (func == POLICY_CHECK)
+		return IMA_APPRAISE_POLICY;
+	else if (func == KEXEC_KERNEL_CHECK)
+		return IMA_APPRAISE_KEXEC;
+	return 0;
+}
+
+static void add_rules(struct ima_rule_entry *entries, int count,
+		      enum policy_rule_list policy_rule)
+{
+	int i = 0;
+
+	for (i = 0; i < count; i++) {
+		struct ima_rule_entry *entry;
+
+		if (policy_rule & IMA_DEFAULT_POLICY)
+			list_add_tail(&entries[i].list, &ima_default_rules);
+
+		if (policy_rule & IMA_CUSTOM_POLICY) {
+			entry = kmemdup(&entries[i], sizeof(*entry),
+					GFP_KERNEL);
+			if (!entry)
+				continue;
+
+			list_add_tail(&entry->list, &ima_policy_rules);
+		}
+		if (entries[i].action == APPRAISE) {
+			if (entries != build_appraise_rules)
+				temp_ima_appraise |=
+					ima_appraise_flag(entries[i].func);
+			else
+				build_ima_appraise |=
+					ima_appraise_flag(entries[i].func);
+		}
+	}
+}
+
+static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
+
+static int __init ima_init_arch_policy(void)
+{
+	const char * const *arch_rules;
+	const char * const *rules;
+	int arch_entries = 0;
+	int i = 0;
+
+	arch_rules = arch_get_ima_policy();
+	if (!arch_rules)
+		return arch_entries;
+
+	/* Get number of rules */
+	for (rules = arch_rules; *rules != NULL; rules++)
+		arch_entries++;
+
+	arch_policy_entry = kcalloc(arch_entries + 1,
+				    sizeof(*arch_policy_entry), GFP_KERNEL);
+	if (!arch_policy_entry)
+		return 0;
+
+	/* Convert each policy string rules to struct ima_rule_entry format */
+	for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
+		char rule[255];
+		int result;
+
+		result = strlcpy(rule, *rules, sizeof(rule));
+
+		INIT_LIST_HEAD(&arch_policy_entry[i].list);
+		result = ima_parse_rule(rule, &arch_policy_entry[i]);
+		if (result) {
+			pr_warn("Skipping unknown architecture policy rule: %s\n",
+				rule);
+			memset(&arch_policy_entry[i], 0,
+			       sizeof(*arch_policy_entry));
+			continue;
+		}
+		i++;
+	}
+	return i;
+}
+
+/**
+ * ima_init_policy - initialize the default measure rules.
+ *
+ * ima_rules points to either the ima_default_rules or the
+ * the new ima_policy_rules.
+ */
+void __init ima_init_policy(void)
+{
+	int build_appraise_entries, arch_entries;
+
+	/* if !ima_policy, we load NO default rules */
+	if (ima_policy)
+		add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
+			  IMA_DEFAULT_POLICY);
+
+	switch (ima_policy) {
+	case ORIGINAL_TCB:
+		add_rules(original_measurement_rules,
+			  ARRAY_SIZE(original_measurement_rules),
+			  IMA_DEFAULT_POLICY);
+		break;
+	case DEFAULT_TCB:
+		add_rules(default_measurement_rules,
+			  ARRAY_SIZE(default_measurement_rules),
+			  IMA_DEFAULT_POLICY);
+		break;
+	default:
+		break;
+	}
+
+	/*
+	 * Based on runtime secure boot flags, insert arch specific measurement
+	 * and appraise rules requiring file signatures for both the initial
+	 * and custom policies, prior to other appraise rules.
+	 * (Highest priority)
+	 */
+	arch_entries = ima_init_arch_policy();
+	if (!arch_entries)
+		pr_info("No architecture policies found\n");
+	else
+		add_rules(arch_policy_entry, arch_entries,
+			  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
+
+	/*
+	 * Insert the builtin "secure_boot" policy rules requiring file
+	 * signatures, prior to other appraise rules.
+	 */
+	if (ima_use_secure_boot)
+		add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
+			  IMA_DEFAULT_POLICY);
+
+	/*
+	 * Insert the build time appraise rules requiring file signatures
+	 * for both the initial and custom policies, prior to other appraise
+	 * rules. As the secure boot rules includes all of the build time
+	 * rules, include either one or the other set of rules, but not both.
+	 */
+	build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
+	if (build_appraise_entries) {
+		if (ima_use_secure_boot)
+			add_rules(build_appraise_rules, build_appraise_entries,
+				  IMA_CUSTOM_POLICY);
+		else
+			add_rules(build_appraise_rules, build_appraise_entries,
+				  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
+	}
+
+	if (ima_use_appraise_tcb)
+		add_rules(default_appraise_rules,
+			  ARRAY_SIZE(default_appraise_rules),
+			  IMA_DEFAULT_POLICY);
+
+	ima_update_policy_flag();
+}
+
+/* Make sure we have a valid policy, at least containing some rules. */
+int ima_check_policy(void)
+{
+	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.  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)
+{
+	struct list_head *policy = &ima_policy_rules;
+
+	list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
+
+	if (ima_rules != policy) {
+		ima_policy_flag = 0;
+		ima_rules = policy;
+
+		/*
+		 * IMA architecture specific policy rules are specified
+		 * as strings and converted to an array of ima_entry_rules
+		 * on boot.  After loading a custom policy, free the
+		 * architecture specific rules stored as an array.
+		 */
+		kfree(arch_policy_entry);
+	}
+	ima_update_policy_flag();
+
+	/* Custom IMA policy has been loaded */
+	ima_process_queued_keys();
+}
+
+/* Keep the enumeration in sync with the policy_tokens! */
+enum {
+	Opt_measure, Opt_dont_measure,
+	Opt_appraise, Opt_dont_appraise,
+	Opt_audit, Opt_hash, Opt_dont_hash,
+	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_fsname,
+	Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
+	Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
+	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
+	Opt_appraise_type, Opt_appraise_flag,
+	Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
+	Opt_err
+};
+
+static const match_table_t policy_tokens = {
+	{Opt_measure, "measure"},
+	{Opt_dont_measure, "dont_measure"},
+	{Opt_appraise, "appraise"},
+	{Opt_dont_appraise, "dont_appraise"},
+	{Opt_audit, "audit"},
+	{Opt_hash, "hash"},
+	{Opt_dont_hash, "dont_hash"},
+	{Opt_obj_user, "obj_user=%s"},
+	{Opt_obj_role, "obj_role=%s"},
+	{Opt_obj_type, "obj_type=%s"},
+	{Opt_subj_user, "subj_user=%s"},
+	{Opt_subj_role, "subj_role=%s"},
+	{Opt_subj_type, "subj_type=%s"},
+	{Opt_func, "func=%s"},
+	{Opt_mask, "mask=%s"},
+	{Opt_fsmagic, "fsmagic=%s"},
+	{Opt_fsname, "fsname=%s"},
+	{Opt_fsuuid, "fsuuid=%s"},
+	{Opt_uid_eq, "uid=%s"},
+	{Opt_euid_eq, "euid=%s"},
+	{Opt_fowner_eq, "fowner=%s"},
+	{Opt_uid_gt, "uid>%s"},
+	{Opt_euid_gt, "euid>%s"},
+	{Opt_fowner_gt, "fowner>%s"},
+	{Opt_uid_lt, "uid<%s"},
+	{Opt_euid_lt, "euid<%s"},
+	{Opt_fowner_lt, "fowner<%s"},
+	{Opt_appraise_type, "appraise_type=%s"},
+	{Opt_appraise_flag, "appraise_flag=%s"},
+	{Opt_permit_directio, "permit_directio"},
+	{Opt_pcr, "pcr=%s"},
+	{Opt_template, "template=%s"},
+	{Opt_keyrings, "keyrings=%s"},
+	{Opt_err, NULL}
+};
+
+static int ima_lsm_rule_init(struct ima_rule_entry *entry,
+			     substring_t *args, int lsm_rule, int audit_type)
+{
+	int result;
+
+	if (entry->lsm[lsm_rule].rule)
+		return -EINVAL;
+
+	entry->lsm[lsm_rule].args_p = match_strdup(args);
+	if (!entry->lsm[lsm_rule].args_p)
+		return -ENOMEM;
+
+	entry->lsm[lsm_rule].type = audit_type;
+	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
+				      entry->lsm[lsm_rule].args_p,
+				      &entry->lsm[lsm_rule].rule);
+	if (!entry->lsm[lsm_rule].rule) {
+		pr_warn("rule for LSM \'%s\' is undefined\n",
+			entry->lsm[lsm_rule].args_p);
+
+		if (ima_rules == &ima_default_rules) {
+			kfree(entry->lsm[lsm_rule].args_p);
+			entry->lsm[lsm_rule].args_p = NULL;
+			result = -EINVAL;
+		} else
+			result = 0;
+	}
+
+	return result;
+}
+
+static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
+			      bool (*rule_operator)(kuid_t, kuid_t))
+{
+	if (!ab)
+		return;
+
+	if (rule_operator == &uid_gt)
+		audit_log_format(ab, "%s>", key);
+	else if (rule_operator == &uid_lt)
+		audit_log_format(ab, "%s<", key);
+	else
+		audit_log_format(ab, "%s=", key);
+	audit_log_format(ab, "%s ", value);
+}
+static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
+{
+	ima_log_string_op(ab, key, value, NULL);
+}
+
+/*
+ * Validating the appended signature included in the measurement list requires
+ * the file hash calculated without the appended signature (i.e., the 'd-modsig'
+ * field). Therefore, notify the user if they have the 'modsig' field but not
+ * the 'd-modsig' field in the template.
+ */
+static void check_template_modsig(const struct ima_template_desc *template)
+{
+#define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
+	bool has_modsig, has_dmodsig;
+	static bool checked;
+	int i;
+
+	/* We only need to notify the user once. */
+	if (checked)
+		return;
+
+	has_modsig = has_dmodsig = false;
+	for (i = 0; i < template->num_fields; i++) {
+		if (!strcmp(template->fields[i]->field_id, "modsig"))
+			has_modsig = true;
+		else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
+			has_dmodsig = true;
+	}
+
+	if (has_modsig && !has_dmodsig)
+		pr_notice(MSG);
+
+	checked = true;
+#undef MSG
+}
+
+static bool ima_validate_rule(struct ima_rule_entry *entry)
+{
+	/* Ensure that the action is set and is compatible with the flags */
+	if (entry->action == UNKNOWN)
+		return false;
+
+	if (entry->action != MEASURE && entry->flags & IMA_PCR)
+		return false;
+
+	if (entry->action != APPRAISE &&
+	    entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST))
+		return false;
+
+	/*
+	 * The IMA_FUNC bit must be set if and only if there's a valid hook
+	 * function specified, and vice versa. Enforcing this property allows
+	 * for the NONE case below to validate a rule without an explicit hook
+	 * function.
+	 */
+	if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
+	    (!(entry->flags & IMA_FUNC) && entry->func != NONE))
+		return false;
+
+	/*
+	 * Ensure that the hook function is compatible with the other
+	 * components of the rule
+	 */
+	switch (entry->func) {
+	case NONE:
+	case FILE_CHECK:
+	case MMAP_CHECK:
+	case BPRM_CHECK:
+	case CREDS_CHECK:
+	case POST_SETATTR:
+	case FIRMWARE_CHECK:
+	case POLICY_CHECK:
+		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
+				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
+				     IMA_INMASK | IMA_EUID | IMA_PCR |
+				     IMA_FSNAME | IMA_DIGSIG_REQUIRED |
+				     IMA_PERMIT_DIRECTIO))
+			return false;
+
+		break;
+	case MODULE_CHECK:
+	case KEXEC_KERNEL_CHECK:
+	case KEXEC_INITRAMFS_CHECK:
+		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
+				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
+				     IMA_INMASK | IMA_EUID | IMA_PCR |
+				     IMA_FSNAME | IMA_DIGSIG_REQUIRED |
+				     IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
+				     IMA_CHECK_BLACKLIST))
+			return false;
+
+		break;
+	case KEXEC_CMDLINE:
+		if (entry->action & ~(MEASURE | DONT_MEASURE))
+			return false;
+
+		if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
+				     IMA_FOWNER | IMA_FSUUID | IMA_EUID |
+				     IMA_PCR | IMA_FSNAME))
+			return false;
+
+		break;
+	case KEY_CHECK:
+		if (entry->action & ~(MEASURE | DONT_MEASURE))
+			return false;
+
+		if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
+				     IMA_KEYRINGS))
+			return false;
+
+		if (ima_rule_contains_lsm_cond(entry))
+			return false;
+
+		break;
+	default:
+		return false;
+	}
+
+	/* Ensure that combinations of flags are compatible with each other */
+	if (entry->flags & IMA_CHECK_BLACKLIST &&
+	    !(entry->flags & IMA_MODSIG_ALLOWED))
+		return false;
+
+	return true;
+}
+
+static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
+{
+	struct audit_buffer *ab;
+	char *from;
+	char *p;
+	bool uid_token;
+	struct ima_template_desc *template_desc;
+	int result = 0;
+
+	ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
+				       AUDIT_INTEGRITY_POLICY_RULE);
+
+	entry->uid = INVALID_UID;
+	entry->fowner = INVALID_UID;
+	entry->uid_op = &uid_eq;
+	entry->fowner_op = &uid_eq;
+	entry->action = UNKNOWN;
+	while ((p = strsep(&rule, " \t")) != NULL) {
+		substring_t args[MAX_OPT_ARGS];
+		int token;
+		unsigned long lnum;
+
+		if (result < 0)
+			break;
+		if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
+			continue;
+		token = match_token(p, policy_tokens, args);
+		switch (token) {
+		case Opt_measure:
+			ima_log_string(ab, "action", "measure");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = MEASURE;
+			break;
+		case Opt_dont_measure:
+			ima_log_string(ab, "action", "dont_measure");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = DONT_MEASURE;
+			break;
+		case Opt_appraise:
+			ima_log_string(ab, "action", "appraise");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = APPRAISE;
+			break;
+		case Opt_dont_appraise:
+			ima_log_string(ab, "action", "dont_appraise");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = DONT_APPRAISE;
+			break;
+		case Opt_audit:
+			ima_log_string(ab, "action", "audit");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = AUDIT;
+			break;
+		case Opt_hash:
+			ima_log_string(ab, "action", "hash");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = HASH;
+			break;
+		case Opt_dont_hash:
+			ima_log_string(ab, "action", "dont_hash");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = DONT_HASH;
+			break;
+		case Opt_func:
+			ima_log_string(ab, "func", args[0].from);
+
+			if (entry->func)
+				result = -EINVAL;
+
+			if (strcmp(args[0].from, "FILE_CHECK") == 0)
+				entry->func = FILE_CHECK;
+			/* PATH_CHECK is for backwards compat */
+			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
+				entry->func = FILE_CHECK;
+			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
+				entry->func = MODULE_CHECK;
+			else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
+				entry->func = FIRMWARE_CHECK;
+			else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
+				|| (strcmp(args[0].from, "MMAP_CHECK") == 0))
+				entry->func = MMAP_CHECK;
+			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
+				entry->func = BPRM_CHECK;
+			else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
+				entry->func = CREDS_CHECK;
+			else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
+				 0)
+				entry->func = KEXEC_KERNEL_CHECK;
+			else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
+				 == 0)
+				entry->func = KEXEC_INITRAMFS_CHECK;
+			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
+				entry->func = POLICY_CHECK;
+			else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
+				entry->func = KEXEC_CMDLINE;
+			else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
+				 strcmp(args[0].from, "KEY_CHECK") == 0)
+				entry->func = KEY_CHECK;
+			else
+				result = -EINVAL;
+			if (!result)
+				entry->flags |= IMA_FUNC;
+			break;
+		case Opt_mask:
+			ima_log_string(ab, "mask", args[0].from);
+
+			if (entry->mask)
+				result = -EINVAL;
+
+			from = args[0].from;
+			if (*from == '^')
+				from++;
+
+			if ((strcmp(from, "MAY_EXEC")) == 0)
+				entry->mask = MAY_EXEC;
+			else if (strcmp(from, "MAY_WRITE") == 0)
+				entry->mask = MAY_WRITE;
+			else if (strcmp(from, "MAY_READ") == 0)
+				entry->mask = MAY_READ;
+			else if (strcmp(from, "MAY_APPEND") == 0)
+				entry->mask = MAY_APPEND;
+			else
+				result = -EINVAL;
+			if (!result)
+				entry->flags |= (*args[0].from == '^')
+				     ? IMA_INMASK : IMA_MASK;
+			break;
+		case Opt_fsmagic:
+			ima_log_string(ab, "fsmagic", args[0].from);
+
+			if (entry->fsmagic) {
+				result = -EINVAL;
+				break;
+			}
+
+			result = kstrtoul(args[0].from, 16, &entry->fsmagic);
+			if (!result)
+				entry->flags |= IMA_FSMAGIC;
+			break;
+		case Opt_fsname:
+			ima_log_string(ab, "fsname", args[0].from);
+
+			entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
+			if (!entry->fsname) {
+				result = -ENOMEM;
+				break;
+			}
+			result = 0;
+			entry->flags |= IMA_FSNAME;
+			break;
+		case Opt_keyrings:
+			ima_log_string(ab, "keyrings", args[0].from);
+
+			if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
+			    entry->keyrings) {
+				result = -EINVAL;
+				break;
+			}
+
+			entry->keyrings = ima_alloc_rule_opt_list(args);
+			if (IS_ERR(entry->keyrings)) {
+				result = PTR_ERR(entry->keyrings);
+				entry->keyrings = NULL;
+				break;
+			}
+
+			entry->flags |= IMA_KEYRINGS;
+			break;
+		case Opt_fsuuid:
+			ima_log_string(ab, "fsuuid", args[0].from);
+
+			if (!uuid_is_null(&entry->fsuuid)) {
+				result = -EINVAL;
+				break;
+			}
+
+			result = uuid_parse(args[0].from, &entry->fsuuid);
+			if (!result)
+				entry->flags |= IMA_FSUUID;
+			break;
+		case Opt_uid_gt:
+		case Opt_euid_gt:
+			entry->uid_op = &uid_gt;
+			fallthrough;
+		case Opt_uid_lt:
+		case Opt_euid_lt:
+			if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
+				entry->uid_op = &uid_lt;
+			fallthrough;
+		case Opt_uid_eq:
+		case Opt_euid_eq:
+			uid_token = (token == Opt_uid_eq) ||
+				    (token == Opt_uid_gt) ||
+				    (token == Opt_uid_lt);
+
+			ima_log_string_op(ab, uid_token ? "uid" : "euid",
+					  args[0].from, entry->uid_op);
+
+			if (uid_valid(entry->uid)) {
+				result = -EINVAL;
+				break;
+			}
+
+			result = kstrtoul(args[0].from, 10, &lnum);
+			if (!result) {
+				entry->uid = make_kuid(current_user_ns(),
+						       (uid_t) lnum);
+				if (!uid_valid(entry->uid) ||
+				    (uid_t)lnum != lnum)
+					result = -EINVAL;
+				else
+					entry->flags |= uid_token
+					    ? IMA_UID : IMA_EUID;
+			}
+			break;
+		case Opt_fowner_gt:
+			entry->fowner_op = &uid_gt;
+			fallthrough;
+		case Opt_fowner_lt:
+			if (token == Opt_fowner_lt)
+				entry->fowner_op = &uid_lt;
+			fallthrough;
+		case Opt_fowner_eq:
+			ima_log_string_op(ab, "fowner", args[0].from,
+					  entry->fowner_op);
+
+			if (uid_valid(entry->fowner)) {
+				result = -EINVAL;
+				break;
+			}
+
+			result = kstrtoul(args[0].from, 10, &lnum);
+			if (!result) {
+				entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
+				if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
+					result = -EINVAL;
+				else
+					entry->flags |= IMA_FOWNER;
+			}
+			break;
+		case Opt_obj_user:
+			ima_log_string(ab, "obj_user", args[0].from);
+			result = ima_lsm_rule_init(entry, args,
+						   LSM_OBJ_USER,
+						   AUDIT_OBJ_USER);
+			break;
+		case Opt_obj_role:
+			ima_log_string(ab, "obj_role", args[0].from);
+			result = ima_lsm_rule_init(entry, args,
+						   LSM_OBJ_ROLE,
+						   AUDIT_OBJ_ROLE);
+			break;
+		case Opt_obj_type:
+			ima_log_string(ab, "obj_type", args[0].from);
+			result = ima_lsm_rule_init(entry, args,
+						   LSM_OBJ_TYPE,
+						   AUDIT_OBJ_TYPE);
+			break;
+		case Opt_subj_user:
+			ima_log_string(ab, "subj_user", args[0].from);
+			result = ima_lsm_rule_init(entry, args,
+						   LSM_SUBJ_USER,
+						   AUDIT_SUBJ_USER);
+			break;
+		case Opt_subj_role:
+			ima_log_string(ab, "subj_role", args[0].from);
+			result = ima_lsm_rule_init(entry, args,
+						   LSM_SUBJ_ROLE,
+						   AUDIT_SUBJ_ROLE);
+			break;
+		case Opt_subj_type:
+			ima_log_string(ab, "subj_type", args[0].from);
+			result = ima_lsm_rule_init(entry, args,
+						   LSM_SUBJ_TYPE,
+						   AUDIT_SUBJ_TYPE);
+			break;
+		case Opt_appraise_type:
+			ima_log_string(ab, "appraise_type", args[0].from);
+			if ((strcmp(args[0].from, "imasig")) == 0)
+				entry->flags |= IMA_DIGSIG_REQUIRED;
+			else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
+				 strcmp(args[0].from, "imasig|modsig") == 0)
+				entry->flags |= IMA_DIGSIG_REQUIRED |
+						IMA_MODSIG_ALLOWED;
+			else
+				result = -EINVAL;
+			break;
+		case Opt_appraise_flag:
+			ima_log_string(ab, "appraise_flag", args[0].from);
+			if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
+			    strstr(args[0].from, "blacklist"))
+				entry->flags |= IMA_CHECK_BLACKLIST;
+			else
+				result = -EINVAL;
+			break;
+		case Opt_permit_directio:
+			entry->flags |= IMA_PERMIT_DIRECTIO;
+			break;
+		case Opt_pcr:
+			ima_log_string(ab, "pcr", args[0].from);
+
+			result = kstrtoint(args[0].from, 10, &entry->pcr);
+			if (result || INVALID_PCR(entry->pcr))
+				result = -EINVAL;
+			else
+				entry->flags |= IMA_PCR;
+
+			break;
+		case Opt_template:
+			ima_log_string(ab, "template", args[0].from);
+			if (entry->action != MEASURE) {
+				result = -EINVAL;
+				break;
+			}
+			template_desc = lookup_template_desc(args[0].from);
+			if (!template_desc || entry->template) {
+				result = -EINVAL;
+				break;
+			}
+
+			/*
+			 * template_desc_init_fields() does nothing if
+			 * the template is already initialised, so
+			 * it's safe to do this unconditionally
+			 */
+			template_desc_init_fields(template_desc->fmt,
+						 &(template_desc->fields),
+						 &(template_desc->num_fields));
+			entry->template = template_desc;
+			break;
+		case Opt_err:
+			ima_log_string(ab, "UNKNOWN", p);
+			result = -EINVAL;
+			break;
+		}
+	}
+	if (!result && !ima_validate_rule(entry))
+		result = -EINVAL;
+	else if (entry->action == APPRAISE)
+		temp_ima_appraise |= ima_appraise_flag(entry->func);
+
+	if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
+		template_desc = entry->template ? entry->template :
+						  ima_template_desc_current();
+		check_template_modsig(template_desc);
+	}
+
+	audit_log_format(ab, "res=%d", !result);
+	audit_log_end(ab);
+	return result;
+}
+
+/**
+ * ima_parse_add_rule - add a rule to ima_policy_rules
+ * @rule: ima measurement policy rule
+ *
+ * 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)
+{
+	static const char op[] = "update_policy";
+	char *p;
+	struct ima_rule_entry *entry;
+	ssize_t result, len;
+	int audit_info = 0;
+
+	p = strsep(&rule, "\n");
+	len = strlen(p) + 1;
+	p += strspn(p, " \t");
+
+	if (*p == '#' || *p == '\0')
+		return len;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry) {
+		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
+				    NULL, op, "-ENOMEM", -ENOMEM, audit_info);
+		return -ENOMEM;
+	}
+
+	INIT_LIST_HEAD(&entry->list);
+
+	result = ima_parse_rule(p, entry);
+	if (result) {
+		ima_free_rule(entry);
+		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
+				    NULL, op, "invalid-policy", result,
+				    audit_info);
+		return result;
+	}
+
+	list_add_tail(&entry->list, &ima_temp_rules);
+
+	return len;
+}
+
+/**
+ * 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;
+
+	temp_ima_appraise = 0;
+	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
+		list_del(&entry->list);
+		ima_free_rule(entry);
+	}
+}
+
+#define __ima_hook_stringify(func, str)	(#func),
+
+const char *const func_tokens[] = {
+	__ima_hooks(__ima_hook_stringify)
+};
+
+#ifdef	CONFIG_IMA_READ_POLICY
+enum {
+	mask_exec = 0, mask_write, mask_read, mask_append
+};
+
+static const char *const mask_tokens[] = {
+	"^MAY_EXEC",
+	"^MAY_WRITE",
+	"^MAY_READ",
+	"^MAY_APPEND"
+};
+
+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].pattern
+#define mt(token)	mask_tokens[token]
+
+/*
+ * policy_func_show - display the ima_hooks policy rule
+ */
+static void policy_func_show(struct seq_file *m, enum ima_hooks func)
+{
+	if (func > 0 && func < MAX_CHECK)
+		seq_printf(m, "func=%s ", func_tokens[func]);
+	else
+		seq_printf(m, "func=%d ", func);
+}
+
+static void ima_show_rule_opt_list(struct seq_file *m,
+				   const struct ima_rule_opt_list *opt_list)
+{
+	size_t i;
+
+	for (i = 0; i < opt_list->count; i++)
+		seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
+}
+
+int ima_policy_show(struct seq_file *m, void *v)
+{
+	struct ima_rule_entry *entry = v;
+	int i;
+	char tbuf[64] = {0,};
+	int offset = 0;
+
+	rcu_read_lock();
+
+	/* Do not print rules with inactive LSM labels */
+	for (i = 0; i < MAX_LSM_RULES; i++) {
+		if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
+			rcu_read_unlock();
+			return 0;
+		}
+	}
+
+	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));
+	if (entry->action & HASH)
+		seq_puts(m, pt(Opt_hash));
+	if (entry->action & DONT_HASH)
+		seq_puts(m, pt(Opt_dont_hash));
+
+	seq_puts(m, " ");
+
+	if (entry->flags & IMA_FUNC)
+		policy_func_show(m, entry->func);
+
+	if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
+		if (entry->flags & IMA_MASK)
+			offset = 1;
+		if (entry->mask & MAY_EXEC)
+			seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
+		if (entry->mask & MAY_WRITE)
+			seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
+		if (entry->mask & MAY_READ)
+			seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
+		if (entry->mask & MAY_APPEND)
+			seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
+		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_FSNAME) {
+		snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
+		seq_printf(m, pt(Opt_fsname), tbuf);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_KEYRINGS) {
+		seq_puts(m, "keyrings=");
+		ima_show_rule_opt_list(m, entry->keyrings);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_PCR) {
+		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
+		seq_printf(m, pt(Opt_pcr), tbuf);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_FSUUID) {
+		seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_UID) {
+		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+		if (entry->uid_op == &uid_gt)
+			seq_printf(m, pt(Opt_uid_gt), tbuf);
+		else if (entry->uid_op == &uid_lt)
+			seq_printf(m, pt(Opt_uid_lt), tbuf);
+		else
+			seq_printf(m, pt(Opt_uid_eq), tbuf);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_EUID) {
+		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+		if (entry->uid_op == &uid_gt)
+			seq_printf(m, pt(Opt_euid_gt), tbuf);
+		else if (entry->uid_op == &uid_lt)
+			seq_printf(m, pt(Opt_euid_lt), tbuf);
+		else
+			seq_printf(m, pt(Opt_euid_eq), tbuf);
+		seq_puts(m, " ");
+	}
+
+	if (entry->flags & IMA_FOWNER) {
+		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
+		if (entry->fowner_op == &uid_gt)
+			seq_printf(m, pt(Opt_fowner_gt), tbuf);
+		else if (entry->fowner_op == &uid_lt)
+			seq_printf(m, pt(Opt_fowner_lt), tbuf);
+		else
+			seq_printf(m, pt(Opt_fowner_eq), 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),
+					   entry->lsm[i].args_p);
+				break;
+			case LSM_OBJ_ROLE:
+				seq_printf(m, pt(Opt_obj_role),
+					   entry->lsm[i].args_p);
+				break;
+			case LSM_OBJ_TYPE:
+				seq_printf(m, pt(Opt_obj_type),
+					   entry->lsm[i].args_p);
+				break;
+			case LSM_SUBJ_USER:
+				seq_printf(m, pt(Opt_subj_user),
+					   entry->lsm[i].args_p);
+				break;
+			case LSM_SUBJ_ROLE:
+				seq_printf(m, pt(Opt_subj_role),
+					   entry->lsm[i].args_p);
+				break;
+			case LSM_SUBJ_TYPE:
+				seq_printf(m, pt(Opt_subj_type),
+					   entry->lsm[i].args_p);
+				break;
+			}
+			seq_puts(m, " ");
+		}
+	}
+	if (entry->template)
+		seq_printf(m, "template=%s ", entry->template->name);
+	if (entry->flags & IMA_DIGSIG_REQUIRED) {
+		if (entry->flags & IMA_MODSIG_ALLOWED)
+			seq_puts(m, "appraise_type=imasig|modsig ");
+		else
+			seq_puts(m, "appraise_type=imasig ");
+	}
+	if (entry->flags & IMA_CHECK_BLACKLIST)
+		seq_puts(m, "appraise_flag=check_blacklist ");
+	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 */
+
+#if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
+/*
+ * ima_appraise_signature: whether IMA will appraise a given function using
+ * an IMA digital signature. This is restricted to cases where the kernel
+ * has a set of built-in trusted keys in order to avoid an attacker simply
+ * loading additional keys.
+ */
+bool ima_appraise_signature(enum kernel_read_file_id id)
+{
+	struct ima_rule_entry *entry;
+	bool found = false;
+	enum ima_hooks func;
+
+	if (id >= READING_MAX_ID)
+		return false;
+
+	if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
+	    && security_locked_down(LOCKDOWN_KEXEC))
+		return false;
+
+	func = read_idmap[id] ?: FILE_CHECK;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, ima_rules, list) {
+		if (entry->action != APPRAISE)
+			continue;
+
+		/*
+		 * A generic entry will match, but otherwise require that it
+		 * match the func we're looking for
+		 */
+		if (entry->func && entry->func != func)
+			continue;
+
+		/*
+		 * We require this to be a digital signature, not a raw IMA
+		 * hash.
+		 */
+		if (entry->flags & IMA_DIGSIG_REQUIRED)
+			found = true;
+
+		/*
+		 * We've found a rule that matches, so break now even if it
+		 * didn't require a digital signature - a later rule that does
+		 * won't override it, so would be a false positive.
+		 */
+		break;
+	}
+
+	rcu_read_unlock();
+	return found;
+}
+#endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */