[RFC PATCH v2 03/12] security: add ipe lsm policy parser and policy loading

[deven.desai@linux.microsoft.com]

From: Deven Bowers <deven.desai@linux.microsoft.com>

Adds the policy parser and the policy loading to IPE, along with the
related sysfs and securityfs entries.

Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
---
 security/ipe/Kconfig      |   2 +-
 security/ipe/Makefile     |   3 +
 security/ipe/ipe-parse.c  | 898 ++++++++++++++++++++++++++++++++++++++
 security/ipe/ipe-parse.h  |  35 ++
 security/ipe/ipe-policy.c | 180 ++++++++
 security/ipe/ipe-policy.h |  54 +++
 security/ipe/ipe-secfs.c  | 814 ++++++++++++++++++++++++++++++++++
 security/ipe/ipe-secfs.h  |  25 ++
 security/ipe/ipe-sysfs.c  |  86 ++++
 security/ipe/ipe.c        |  13 +
 security/ipe/ipe.h        |   1 +
 11 files changed, 2110 insertions(+), 1 deletion(-)
 create mode 100644 security/ipe/ipe-parse.c
 create mode 100644 security/ipe/ipe-parse.h
 create mode 100644 security/ipe/ipe-policy.c
 create mode 100644 security/ipe/ipe-secfs.c
 create mode 100644 security/ipe/ipe-secfs.h

diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig
index 0c67cd049d0c..ef6fb019be6f 100644
--- a/security/ipe/Kconfig
+++ b/security/ipe/Kconfig
@@ -5,7 +5,7 @@
 
 menuconfig SECURITY_IPE
 	bool "Integrity Policy Enforcement (IPE)"
-	depends on SECURITY && AUDIT
+	depends on SECURITY && AUDIT && SECURITYFS
 	select SYSTEM_DATA_VERIFICATION
 	help
 	  This option enables the Integrity Policy Enforcement subsystem,
diff --git a/security/ipe/Makefile b/security/ipe/Makefile
index aaa2e2c0b2f4..4dcfc5b26b58 100644
--- a/security/ipe/Makefile
+++ b/security/ipe/Makefile
@@ -19,8 +19,11 @@ obj-$(CONFIG_SECURITY_IPE) += \
 	ipe-audit.o \
 	ipe-bp.o \
 	ipe-engine.o \
+	ipe-parse.o \
+	ipe-policy.o \
 	ipe-property.o \
 	ipe-hooks.o \
+	ipe-secfs.o \
 	ipe-sysfs.o \
 
 clean-files := ipe-bp.c
diff --git a/security/ipe/ipe-parse.c b/security/ipe/ipe-parse.c
new file mode 100644
index 000000000000..c5e0111b9c8b
--- /dev/null
+++ b/security/ipe/ipe-parse.c
@@ -0,0 +1,898 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+
+#include "ipe.h"
+#include "ipe-prop-internal.h"
+#include "ipe-hooks.h"
+#include "ipe-parse.h"
+#include "ipe-property.h"
+#include "ipe-audit.h"
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/list_sort.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include <linux/parser.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+
+#define ALLOW_ACTION	"ALLOW"
+#define DENY_ACTION	"DENY"
+#define COMMENT_CHAR	'#'
+#define VER_FSTR	"%hu.%hu.%hu"
+
+/* Internal Type Definitions */
+enum property_priority {
+	other = 0,
+	action = 1,
+	op = 2,
+	default_action = 3,
+	policy_ver = 4,
+	policy_name = 5,
+};
+
+struct token {
+	struct list_head	next_tok;
+	const char		*key;
+	enum property_priority	key_priority;
+	const char		*val;
+};
+
+/* Utility Functions */
+static inline bool is_quote(char c)
+{
+	return c == '"' || c == '\'';
+}
+
+static inline bool valid_token(char *s)
+{
+	return !s || !strpbrk(s, "\"\'");
+}
+
+static inline bool is_default(const struct token *t)
+{
+	return !t->val &&  t->key_priority == default_action;
+}
+
+static inline bool is_operation(const struct token *t)
+{
+	return t->val && t->key_priority == op;
+}
+
+static inline bool is_action(const struct token *t)
+{
+	return t->val && t->key_priority == action;
+}
+
+static inline bool is_name(const struct token *t)
+{
+	return t->val && t->key_priority == policy_name;
+}
+
+static inline bool is_ver(const struct token *t)
+{
+	return t->val && t->key_priority == policy_ver;
+}
+
+static int cmp_pri(void *priv, struct list_head *a, struct list_head *b)
+{
+	struct token *t_a = container_of(a, struct token, next_tok);
+	struct token *t_b = container_of(b, struct token, next_tok);
+
+	return t_b->key_priority - t_a->key_priority;
+}
+
+static char *trim_quotes(char *str)
+{
+	char s;
+	size_t len;
+
+	if (!str)
+		return str;
+
+	s = *str;
+
+	if (is_quote(s)) {
+		len = strlen(str) - 1;
+
+		if (str[len] != s)
+			return NULL;
+
+		str[len] = '\0';
+		++str;
+	}
+
+	return str;
+}
+
+/**
+ * ipe_set_action: Set an action with error checking.
+ * @src: Valid pointer to the source location to set wih the result
+ * @set: Value to apply to @src, if valid
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Attempting to set something that is already set
+ */
+static int ipe_set_action(enum ipe_action *src, enum ipe_action set)
+{
+	if (*src != ipe_action_unset)
+		return -EBADMSG;
+
+	*src = set;
+
+	return 0;
+}
+
+/**
+ * ipe_insert_token: Allocate and append the key=value pair indicated by @val,
+ *		     to the list represented by @head.
+ * @val: Token to parse, of form "key=val".
+ * @head: Head of the list to insert the token structure into.
+ *
+ * If "=val" is omitted, this function will succeed, and the value set will be
+ * NULL.
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Invalid policy syntax
+ * -ENOMEM - No Memory
+ */
+static int ipe_insert_token(char *val, struct list_head *head)
+{
+	char *key;
+	substring_t match[MAX_OPT_ARGS];
+	struct token *tok;
+	const match_table_t prop_priorities = {
+		{ policy_name,		IPE_HEADER_POLICY_NAME },
+		{ policy_ver,		IPE_HEADER_POLICY_VERSION},
+		{ op,			IPE_PROPERTY_OPERATION },
+		{ default_action,	IPE_PROPERTY_DEFAULT },
+		{ action,		IPE_PROPERTY_ACTION },
+		{ other, NULL },
+	};
+
+	key = strsep(&val, "=");
+	if (!key)
+		return -EBADMSG;
+
+	tok = kzalloc(sizeof(*tok), GFP_KERNEL);
+	if (!tok)
+		return -ENOMEM;
+
+	tok->key = key;
+	tok->val = trim_quotes(val);
+	tok->key_priority = match_token(key, prop_priorities, match);
+	INIT_LIST_HEAD(&tok->next_tok);
+
+	list_add_tail(&tok->next_tok, head);
+
+	return 0;
+}
+
+/**
+ * ipe_tokenize_line: Parse a line of text into a list of token structures.
+ * @line: Line to parse.
+ * @list: Head of the list to insert the token structure into.
+ *
+ * The final result will be sorted in the priority order definted by
+ * enum property_priorities to enforce policy structure.
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Invalid policy syntax
+ * -ENOMEM - No Memory
+ * -ENOENT - No tokens were parsed
+ */
+static int ipe_tokenize_line(char *line, struct list_head *list)
+{
+	int rc = 0;
+	size_t i = 0;
+	size_t len = 0;
+	char *tok = NULL;
+	char quote = '\0';
+
+	len = strlen(line);
+
+	for (i = 0; i < len; ++i) {
+		if (quote == '\0' && is_quote(line[i])) {
+			quote = line[i];
+			continue;
+		}
+
+		if (quote != '\0' && line[i] == quote) {
+			quote = '\0';
+			continue;
+		}
+
+		if (quote == '\0' && line[i] == COMMENT_CHAR) {
+			tok = NULL;
+			break;
+		}
+
+		if (isgraph(line[i]) && !tok)
+			tok = &line[i];
+
+		if (quote == '\0' && isspace(line[i])) {
+			line[i] = '\0';
+
+			if (!tok)
+				continue;
+
+			rc = ipe_insert_token(tok, list);
+			if (rc != 0)
+				return rc;
+
+			tok = NULL;
+		}
+	}
+
+	if (quote != '\0')
+		return -EBADMSG;
+
+	if (tok)
+		ipe_insert_token(tok, list);
+
+	if (list_empty(list))
+		return -ENOENT;
+
+	list_sort(NULL, list, cmp_pri);
+
+	return 0;
+}
+
+static inline int ipe_parse_version(const char *val, struct ipe_pol_ver *ver)
+{
+	if (sscanf(val, VER_FSTR, &ver->major, &ver->minor, &ver->rev) != 3)
+		return -EBADMSG;
+
+	return 0;
+}
+
+/**
+ * ipe_parse_action: Given a token, parse the value as if it were an 'action'
+ *		     token.
+ * @action: Token to parse to determine the action.
+ *
+ * Action tokens are of the form: action=(ALLOW|DENY) for more information
+ * about IPE policy, please see the documentation.
+ *
+ * Return:
+ * ipe_action_allow - OK
+ * ipe_action_deny - OK
+ * ipe_action_unset - ERR
+ */
+static enum ipe_action ipe_parse_action(struct token *action)
+{
+	if (!action->val)
+		return ipe_action_unset;
+	else if (!strcmp(action->val, ALLOW_ACTION))
+		return ipe_action_allow;
+	else if (!strcmp(action->val, DENY_ACTION))
+		return ipe_action_deny;
+
+	return ipe_action_unset;
+}
+
+/**
+ * ipe_parse_op: Given a token, parse the value as if it were an 'op' token.
+ * @op: Token to parse to determine the operation.
+ *
+ * "op" tokens are of the form: op=(EXECUTE|FIRMWARE|KEXEC_IMAGE|...)
+ * for more information about IPE policy, please see the documentation.
+ *
+ * Return:
+ * ipe_op_max - ERR
+ * otherwise - OK
+ */
+static enum ipe_op ipe_parse_op(struct token *op)
+{
+	substring_t match[MAX_OPT_ARGS];
+	const match_table_t ops = {
+		{ ipe_op_execute,		IPE_OP_EXECUTE },
+		{ ipe_op_firmware,		IPE_OP_FIRMWARE },
+		{ ipe_op_kexec_image,		IPE_OP_KEXEC_IMAGE },
+		{ ipe_op_kexec_initramfs,	IPE_OP_KEXEC_INITRAMFS },
+		{ ipe_op_x509,			IPE_OP_X509_CERTIFICATE },
+		{ ipe_op_policy,		IPE_OP_POLICY },
+		{ ipe_op_kmodule,		IPE_OP_KMODULE },
+		{ ipe_op_kernel_read,		IPE_OP_KERNEL_READ },
+		{ ipe_op_max,			NULL },
+	};
+
+	return match_token((char *)op->val, ops, match);
+}
+
+/**
+ * ipe_set_default: Set the default of the policy, at various scope levels
+ *		    depending on the value of op.
+ * @op: Operation that was parsed.
+ * @pol: Policy to modify with the newly-parsed default action.
+ * @a: Action token (see parse_action) to parse to determine
+ *     the default.
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Invalid policy format
+ */
+static int ipe_set_default(enum ipe_op op, struct ipe_policy *pol,
+			   struct token *a)
+{
+	int rc = 0;
+	size_t i = 0;
+	enum ipe_action act = ipe_parse_action(a);
+
+	if (act == ipe_action_unset)
+		return -EBADMSG;
+
+	if (op == ipe_op_max)
+		return ipe_set_action(&pol->def, act);
+
+	if (op == ipe_op_kernel_read) {
+		for (i = ipe_op_firmware; i <= ipe_op_kmodule; ++i) {
+			rc = ipe_set_action(&pol->ops[i].def, act);
+			if (rc != 0)
+				return rc;
+		}
+		return 0;
+	}
+
+	return ipe_set_action(&pol->ops[op].def, act);
+}
+
+/**
+ * ipe_parse_default: Parse a default statement of an IPE policy modify @pol
+ *		      with the proper changes
+ * @tokens: List of tokens parsed from the line
+ * @pol: Policy to modify with the newly-parsed default action
+ *
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Invalid policy format
+ * -ENOENT - Unknown policy structure
+ */
+static int ipe_parse_default(struct list_head *tokens,
+			     struct ipe_policy *pol)
+{
+	struct token *f = NULL;
+	struct token *s = NULL;
+	struct token *t = NULL;
+	enum ipe_op i = ipe_op_max;
+
+	f = list_first_entry(tokens, struct token, next_tok);
+	s = list_next_entry(f, next_tok);
+	if (is_action(s))
+		return ipe_set_default(ipe_op_max, pol, s);
+
+	i = ipe_parse_op(s);
+	if (i == ipe_op_max)
+		return -ENOENT;
+
+	t = list_next_entry(s, next_tok);
+	if (is_action(t)) {
+		t = list_next_entry(s, next_tok);
+		return ipe_set_default(i, pol, t);
+	}
+
+	return -ENOENT;
+}
+
+/**
+ * ipe_free_token_list - Free a list of tokens, and then reinitialize @list
+ *			 dropping all tokens.
+ * @list: List to be freed.
+ */
+static void ipe_free_token_list(struct list_head *list)
+{
+	struct token *ptr, *next;
+
+	list_for_each_entry_safe(ptr, next, list, next_tok)
+		kfree(ptr);
+
+	INIT_LIST_HEAD(list);
+}
+
+/**
+ * ipe_free_prop - Deallocator for an ipe_prop_container structure.
+ * @cont: Object to free.
+ */
+static void ipe_free_prop(struct ipe_prop_container *cont)
+{
+	if (IS_ERR_OR_NULL(cont))
+		return;
+
+	if (cont->prop->free_val)
+		cont->prop->free_val(&cont->value);
+	kfree(cont);
+}
+
+/**
+ * ipe_alloc_prop: Allocator for a ipe_prop_container structure.
+ * @tok: Token structure representing the "key=value" pair of the property.
+ *
+ * Return:
+ * Pointer to ipe_rule - OK
+ * ERR_PTR(-ENOMEM) - Allocation failed
+ */
+static struct ipe_prop_container *ipe_alloc_prop(const struct token *tok)
+{
+	int rc = 0;
+	const struct ipe_property *prop = NULL;
+	struct ipe_prop_container *cont = NULL;
+
+	prop = ipe_lookup_prop(tok->key);
+	if (!prop) {
+		rc = -ENOENT;
+		goto err;
+	}
+
+	cont = kzalloc(sizeof(*cont), GFP_KERNEL);
+	if (!cont) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	INIT_LIST_HEAD(&cont->next);
+
+	rc = prop->parse(tok->val, &cont->value);
+	if (rc != 0)
+		goto err;
+
+	cont->prop = prop;
+
+	return cont;
+err:
+	ipe_free_prop(cont);
+	return ERR_PTR(rc);
+}
+
+/**
+ * ipe_free_rule: Deallocator for an ipe_rule structure.
+ * @rule: Object to free.
+ */
+static void ipe_free_rule(struct ipe_rule *rule)
+{
+	struct ipe_prop_container *ptr;
+	struct list_head *l_ptr, *l_next;
+
+	if (IS_ERR_OR_NULL(rule))
+		return;
+
+	list_for_each_safe(l_ptr, l_next, &rule->props) {
+		ptr = container_of(l_ptr, struct ipe_prop_container, next);
+		list_del(l_ptr);
+		ipe_free_prop(ptr);
+	}
+
+	kfree(rule);
+}
+
+/**
+ * ipe_alloc_rule: Allocate a ipe_rule structure, for operation @op, parsed
+ *		   from the first token in list @head.
+ * @op: Operation parsed from the first token in @head.
+ * @t: The first token in @head that was parsed.
+ * @head: List of remaining tokens to parse.
+ *
+ * Return:
+ * Valid ipe_rule pointer - OK
+ * ERR_PTR(-EBADMSG) - Invalid syntax
+ * ERR_PTR(-ENOMEM) - Out of memory
+ */
+static struct ipe_rule *ipe_alloc_rule(enum ipe_op op, struct token *t,
+				       struct list_head *head)
+{
+	int rc = 0;
+	struct token *ptr;
+	enum ipe_action act;
+	struct ipe_rule *rule = NULL;
+	struct ipe_prop_container *prop = NULL;
+
+	ptr = list_next_entry(t, next_tok);
+	if (!is_action(ptr)) {
+		rc = -EBADMSG;
+		goto err;
+	}
+
+	act = ipe_parse_action(ptr);
+	if (act == ipe_action_unset) {
+		rc = -EBADMSG;
+		goto err;
+	}
+
+	rule = kzalloc(sizeof(*rule), GFP_KERNEL);
+	if (!rule) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	INIT_LIST_HEAD(&rule->props);
+	INIT_LIST_HEAD(&rule->next);
+	rule->action = act;
+	rule->op = op;
+
+	list_for_each_entry_continue(ptr, head, next_tok) {
+		prop = ipe_alloc_prop(ptr);
+
+		if (IS_ERR(prop)) {
+			rc = PTR_ERR(prop);
+			goto err;
+		}
+
+		list_add_tail(&prop->next, &rule->props);
+	}
+
+	return rule;
+err:
+	ipe_free_prop(prop);
+	ipe_free_rule(rule);
+	return ERR_PTR(rc);
+}
+
+/**
+ * ipe_dup_prop: Duplicate an ipe_prop_container structure
+ * @p: Container to duplicate.
+ *
+ * This function is used to duplicate individual properties within a rule.
+ * It should only be called in operations that actually map to one or more
+ * operations.
+ *
+ * Return:
+ * Valid ipe_prop_container - OK
+ * ERR_PTR(-ENOMEM) - Out of memory
+ * Other Errors - see various property duplicator functions
+ */
+static
+struct ipe_prop_container *ipe_dup_prop(const struct ipe_prop_container *p)
+{
+	int rc = 0;
+	struct ipe_prop_container *dup;
+
+	dup = kzalloc(sizeof(*dup), GFP_KERNEL);
+	if (!dup) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	dup->prop = p->prop;
+	INIT_LIST_HEAD(&dup->next);
+
+	rc = p->prop->dup(p->value, &dup->value);
+	if (rc != 0)
+		goto err;
+
+	return dup;
+err:
+	ipe_free_prop(dup);
+	return ERR_PTR(rc);
+}
+
+/**
+ * ipe_dup_rule: Duplicate a policy rule, used for pseudo hooks like
+ *		 KERNEL_READ to map a policy rule across all hooks.
+ * @r: Rule to duplicate.
+ *
+ * Return:
+ * valid ipe_rule - OK
+ * ERR_PTR(-ENOMEM) - Out of memory
+ * Other Errors - See ipe_dup_prop
+ */
+static struct ipe_rule *ipe_dup_rule(const struct ipe_rule *r)
+{
+	int rc = 0;
+	struct ipe_rule *dup;
+	struct ipe_prop_container *ptr;
+
+	dup = kzalloc(sizeof(*dup), GFP_KERNEL);
+	if (!dup) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	dup->op = r->op;
+	dup->action = r->action;
+	INIT_LIST_HEAD(&dup->props);
+	INIT_LIST_HEAD(&dup->next);
+
+	list_for_each_entry(ptr, &r->props, next) {
+		struct ipe_prop_container *prop2;
+
+		prop2 = ipe_dup_prop(ptr);
+		if (IS_ERR(prop2)) {
+			rc = PTR_ERR(prop2);
+			goto err;
+		}
+
+		list_add_tail(&prop2->next, &dup->props);
+	}
+
+	return dup;
+err:
+	ipe_free_rule(dup);
+	return ERR_PTR(rc);
+}
+
+/**
+ * ipe_free_policy: Deallocate an ipe_policy structure.
+ * @pol: Policy to free.
+ */
+void ipe_free_policy(struct ipe_policy *pol)
+{
+	size_t i;
+	struct ipe_rule *ptr;
+	struct ipe_rule_table *op;
+	struct list_head *l_ptr, *l_next;
+
+	if (IS_ERR_OR_NULL(pol))
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(pol->ops); ++i) {
+		op = &pol->ops[i];
+
+		list_for_each_safe(l_ptr, l_next, &op->rules) {
+			ptr = list_entry(l_ptr, struct ipe_rule, next);
+			list_del(l_ptr);
+			ipe_free_rule(ptr);
+		}
+	}
+
+	kfree(pol->policy_name);
+	kfree(pol);
+	pol = NULL;
+}
+
+/**
+ * ipe_alloc_policy: Give a list of tokens representing the first line of the
+ *		     token, attempt to parse it as an IPE policy header, and
+ *		     allocate a policy structure based on those values.
+ * @tokens: List of tokens parsed from the first line of the policy
+ *
+ * Return:
+ * Valid ipe_policy pointer - OK
+ * ERR_PTR(-ENOMEM) - Out of memory
+ * ERR_PTR(-EBADMSG) - Invalid policy syntax
+ */
+static struct ipe_policy *ipe_alloc_policy(struct list_head *tokens)
+{
+	size_t i;
+	int rc = 0;
+	struct token *name = NULL;
+	struct token *ver = NULL;
+	struct ipe_policy *lp = NULL;
+
+	name = list_first_entry(tokens, struct token, next_tok);
+	if (!is_name(name)) {
+		rc = -EBADMSG;
+		goto err;
+	}
+
+	if (list_is_singular(tokens)) {
+		rc = -EBADMSG;
+		goto err;
+	}
+
+	ver = list_next_entry(name, next_tok);
+	if (!is_ver(ver)) {
+		rc = -EBADMSG;
+		goto err;
+	}
+
+	lp = kzalloc(sizeof(*lp), GFP_KERNEL);
+	if (!lp) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	lp->policy_name = kstrdup(name->val, GFP_KERNEL);
+	if (!lp->policy_name) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	rc = ipe_parse_version(ver->val, &lp->policy_version);
+	if (rc != 0)
+		goto err;
+
+	for (i = 0; i < ARRAY_SIZE(lp->ops); ++i) {
+		lp->ops[i].def = ipe_action_unset;
+		INIT_LIST_HEAD(&lp->ops[i].rules);
+	}
+
+	lp->def = ipe_action_unset;
+
+	return lp;
+err:
+	ipe_free_policy(lp);
+	return ERR_PTR(rc);
+}
+
+/**
+ * ipe_add_rule_for_range: Given a ipe_rule @r, duplicate @r and add the rule
+ *			   to @pol for the operation range @start to @end.
+ * @start: The starting point of the range to add the rule to.
+ * @end: The ending point of the range to add the rule to.
+ * @r: The rule to copy.
+ * @pol: Policy structure to modify with the result.
+ *
+ * This is @start to @end, inclusive. @r is still valid after this function,
+ * and should be freed if appropriate.
+ *
+ * Return:
+ * 0 - OK
+ * Other Errors - See ipe_dup_prop
+ */
+static int ipe_add_rule_for_range(enum ipe_op start, enum ipe_op end,
+				  struct ipe_rule *r, struct ipe_policy *pol)
+{
+	enum ipe_op i;
+	struct ipe_rule *cpy = NULL;
+
+	for (i = start; i <= end; ++i) {
+		cpy = ipe_dup_rule(r);
+		if (IS_ERR(cpy))
+			return PTR_ERR(cpy);
+
+		list_add_tail(&cpy->next, &pol->ops[i].rules);
+	}
+
+	return 0;
+}
+
+/**
+ * ipe_parse_line: Given a list of tokens, attempt to parse it into a rule
+ *		   structure, and add it to the passed-in ipe_policy structure.
+ * @tokens: List of tokens that were parsed.
+ * @pol: Policy structure to modify with the result.
+ *
+ * Return:
+ * 0 - OK
+ * -ENOENT - Unrecognized property
+ * -ENOMEM - Out of memory
+ * Other Errors - See ipe_dup_prop
+ */
+static int ipe_parse_line(struct list_head *tokens,
+			  struct ipe_policy *pol)
+{
+	int rc = 0;
+	struct token *f;
+	enum ipe_op i = ipe_op_max;
+	struct ipe_rule *rule = NULL;
+
+	f = list_first_entry(tokens, struct token, next_tok);
+
+	switch (f->key_priority) {
+	case default_action:
+		rc = ipe_parse_default(tokens, pol);
+		break;
+	case op:
+		i = ipe_parse_op(f);
+		if (i == ipe_op_max)
+			return -ENOENT;
+
+		if (list_is_singular(tokens))
+			return -EBADMSG;
+
+		rule = ipe_alloc_rule(i, f, tokens);
+		if (IS_ERR(rule)) {
+			rc = PTR_ERR(rule);
+			goto cleanup;
+		}
+
+		if (i == ipe_op_kernel_read) {
+			rc = ipe_add_rule_for_range(ipe_op_firmware,
+						    ipe_op_kmodule, rule, pol);
+			if (rc != 0)
+				goto cleanup;
+		} else {
+			list_add_tail(&rule->next, &pol->ops[i].rules);
+			rule = NULL;
+		}
+		break;
+	default:
+		return -ENOENT;
+	}
+
+cleanup:
+	ipe_free_rule(rule);
+	return rc;
+}
+
+/**
+ * ipe_remap_policy_defaults: Remap all defaults not specified by policy to
+ *			      'allow' to preserve compatibility.
+ * @p: Policy to modify.
+ *
+ * This function's behavior changes when strict_parse is set. When the strict
+ * parser is enabled, this function will break backwards policy compatibility,
+ * erroring on an unset default.
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - (Only with strict parse) A default was left unset.
+ */
+static int ipe_remap_policy_defaults(struct ipe_policy *p)
+{
+	size_t i;
+
+	if (p->def == ipe_action_unset) {
+		for (i = 0; i < ARRAY_SIZE(p->ops); ++i) {
+			if (p->ops[i].def == ipe_action_unset) {
+				ipe_audit_unset_remap((enum ipe_op)i);
+				if (strict_parse)
+					return -EBADMSG;
+				p->ops[i].def = ipe_action_allow;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * ipe_parse_policy: Given a string, parse the string into an IPE policy
+ *		     structure.
+ * @policy: NULL terminated string to parse.
+ *
+ * This function's behavior changes when strict_parse is set. When the strict
+ * parser is enabled, this function will break backwards policy compatibility,
+ * erroring on unknown syntax. This function will modify @policy.
+ *
+ * Return:
+ * Valid ipe_policy structure - OK
+ * ERR_PTR(-EBADMSG) - Invalid Policy Syntax (Unrecoverable)
+ * ERR_PTR(-ENOMEM) - Out of Memory
+ */
+struct ipe_policy *ipe_parse_policy(char *policy)
+{
+	int rc = 0;
+	size_t i = 1;
+	char *p = NULL;
+	LIST_HEAD(t_list);
+	struct ipe_policy *local_p = NULL;
+
+	while ((p = strsep(&policy, "\n\0")) != NULL) {
+		rc = ipe_tokenize_line(p, &t_list);
+		if (rc == -ENOENT) {
+			++i;
+			continue;
+		}
+		if (rc != 0)
+			goto err;
+
+		if (!local_p) {
+			local_p = ipe_alloc_policy(&t_list);
+			if (IS_ERR(local_p)) {
+				rc = PTR_ERR(local_p);
+				goto err;
+			}
+		} else {
+			rc = ipe_parse_line(&t_list, local_p);
+			if (rc == -ENOENT) {
+				ipe_audit_ignore_line(i);
+				if (strict_parse) {
+					rc = -EBADMSG;
+					goto err;
+				}
+			} else if (rc != 0) {
+				goto err;
+			}
+		}
+
+		ipe_free_token_list(&t_list);
+		++i;
+	}
+
+	rc = ipe_remap_policy_defaults(local_p);
+	if (rc != 0)
+		goto err;
+
+	return local_p;
+err:
+	ipe_free_token_list(&t_list);
+	ipe_free_policy(local_p);
+	return ERR_PTR(rc);
+}
diff --git a/security/ipe/ipe-parse.h b/security/ipe/ipe-parse.h
new file mode 100644
index 000000000000..99310b5c3e00
--- /dev/null
+++ b/security/ipe/ipe-parse.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+
+#include "ipe-policy.h"
+
+#include <linux/types.h>
+
+#ifndef IPE_PARSE_H
+#define IPE_PARSE_H
+
+/**
+ * ipe_parse_policy: Given a string, parse the string into an IPE policy
+ *		     structure.
+ * @policy: NULL terminated string to parse.
+ *
+ * This function's behavior changes when strict_parse is set. When the strict
+ * parser is enabled, this function will break backwards policy compatibility,
+ * erroring on unknown syntax. This function will modify @policy.
+ *
+ * Return:
+ * Valid ipe_policy structure - OK
+ * ERR_PTR(-EBADMSG) - Invalid Policy Syntax (Unrecoverable)
+ * ERR_PTR(-ENOMEM) - Out of Memory
+ */
+struct ipe_policy *ipe_parse_policy(char *policy);
+
+/**
+ * ipe_free_policy: Deallocate an ipe_policy structure.
+ * @pol: Policy to free.
+ */
+void ipe_free_policy(struct ipe_policy *pol);
+
+#endif /* IPE_AUDIT_H */
diff --git a/security/ipe/ipe-policy.c b/security/ipe/ipe-policy.c
new file mode 100644
index 000000000000..f39282160095
--- /dev/null
+++ b/security/ipe/ipe-policy.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+
+#include "ipe.h"
+#include "ipe-secfs.h"
+#include "ipe-policy.h"
+#include "ipe-parse.h"
+#include "ipe-audit.h"
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/lockdep.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/rcupdate.h>
+
+static DEFINE_MUTEX(policy_lock);
+
+#define VER_TO_UINT64(_major, _minor, _rev) \
+	((((((u64)(_major)) << 16) | ((u64)(_minor))) << 16) | ((u64)(_rev)))
+
+/**
+ * ipe_is_version_allowed: Determine if @new has a greater or equal
+ *			   policy version than @old.
+ * @old: The policy to compare against.
+ * @new: The policy staged to replace @old.
+ *
+ * Return:
+ * true - @new has a policy version >= than @old
+ * false - @new does not have a policy version >= than @old
+ */
+static bool ipe_is_version_allowed(const struct ipe_pol_ver *old,
+				   const struct ipe_pol_ver *new)
+{
+	u64 old_ver = VER_TO_UINT64(old->major, old->minor, old->rev);
+	u64 new_ver = VER_TO_UINT64(new->major, new->minor, new->rev);
+
+	return new_ver >= old_ver;
+}
+
+/**
+ * ipe_is_valid_policy: determine if @old is allowed to replace @new.
+ * @old: policy that the @new is supposed to replace. Can be NULL.
+ * @new: the policy that is supposed to replace @new.
+ *
+ * Return:
+ * true - @new can replace @old
+ * false - @new cannot replace @old
+ */
+bool ipe_is_valid_policy(const struct ipe_policy *old,
+			 const struct ipe_policy *new)
+{
+	if (old)
+		return ipe_is_version_allowed(&old->policy_version,
+					      &new->policy_version);
+	return true;
+}
+
+/**
+ * ipe_is_active_policy: Determine if @policy is the currently active policy.
+ * @policy: Policy to check if it's the active policy.
+ *
+ * NOTE: If this attribute is needed to be consistent over a critical section,
+ *       do not use this function, as it does not hold the read lock over the
+ *       entirety of the critical section.
+ *
+ * Return:
+ * true - @policy is the active policy
+ * false - @policy is not the active policy
+ */
+bool ipe_is_active_policy(const struct ipe_policy *policy)
+{
+	bool result;
+
+	rcu_read_lock();
+
+	result = rcu_dereference(ipe_active_policy) == policy;
+
+	rcu_read_unlock();
+
+	return result;
+}
+
+/**
+ * ipe_update_active_policy: Determine if @old is the active policy, and update
+ *			     the active policy if necessary.
+ * @old: The previous policy that the update is trying to replace.
+ * @new: The new policy attempting to replace @old.
+ *
+ * If @old is not the active policy, nothing will be done.
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Invalid Policy
+ */
+int ipe_update_active_policy(const struct ipe_policy *old,
+			     const struct ipe_policy *new)
+{
+	int rc = 0;
+	const struct ipe_policy *curr_policy = NULL;
+
+	/* no active policy, safe to update */
+	if (!ipe_active_policy)
+		return 0;
+
+	mutex_lock(&policy_lock);
+
+	curr_policy = rcu_dereference_protected(ipe_active_policy,
+						lockdep_is_held(&policy_lock));
+
+	if (curr_policy == old) {
+		if (!ipe_is_valid_policy(curr_policy, new)) {
+			rc = -EBADMSG;
+			goto cleanup;
+		}
+
+		ipe_audit_policy_activation(new);
+
+		(void)rcu_replace_pointer(ipe_active_policy, new,
+					  lockdep_is_held(&policy_lock));
+	}
+
+	mutex_unlock(&policy_lock);
+	synchronize_rcu();
+
+	return rc;
+cleanup:
+	mutex_unlock(&policy_lock);
+	return rc;
+}
+
+/**
+ * ipe_activate_policy: Set a specific policy as the active policy.
+ * @pol: The policy to set as the active policy.
+ *
+ * This is only called by the sysctl "ipe.active_policy".
+ *
+ * Return:
+ * 0 - OK
+ * -EINVAL - Policy that is being activated is lower in version than
+ *	     currently running policy.
+ */
+int ipe_activate_policy(const struct ipe_policy *pol)
+{
+	int rc = 0;
+	const struct ipe_policy *curr_policy = NULL;
+
+	mutex_lock(&policy_lock);
+
+	curr_policy = rcu_dereference_protected(ipe_active_policy,
+						lockdep_is_held(&policy_lock));
+
+	/*
+	 * User-set policies must be >= to current running policy.
+	 */
+	if (!ipe_is_valid_policy(curr_policy, pol)) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	ipe_audit_policy_activation(pol);
+
+	/* cleanup of this pointer is handled by the secfs removal */
+	(void)rcu_replace_pointer(ipe_active_policy, pol,
+				  lockdep_is_held(&policy_lock));
+
+	mutex_unlock(&policy_lock);
+	synchronize_rcu();
+
+	return 0;
+cleanup:
+	mutex_unlock(&policy_lock);
+	return rc;
+}
diff --git a/security/ipe/ipe-policy.h b/security/ipe/ipe-policy.h
index c0c9f2962c92..c9da982ef2d4 100644
--- a/security/ipe/ipe-policy.h
+++ b/security/ipe/ipe-policy.h
@@ -59,4 +59,58 @@ struct ipe_policy {
 	struct ipe_rule_table ops[ipe_op_max - 1];
 };
 
+/**
+ * ipe_is_valid_policy: determine if @old is allowed to replace @new.
+ * @old: policy that the @new is supposed to replace. Can be NULL.
+ * @new: the policy that is supposed to replace @new.
+ *
+ * Return:
+ * true - @new can replace @old
+ * false - @new cannot replace @old
+ */
+bool ipe_is_valid_policy(const struct ipe_policy *old,
+			 const struct ipe_policy *new);
+
+/**
+ * ipe_is_active_policy: Determine if @policy is the currently active policy.
+ * @policy: Policy to check if it's the active policy.
+ *
+ * NOTE: If this attribute is needed to be consistent over a critical section,
+ *       do not use this function, as it does not hold the read lock over the
+ *       entirety of the critical section.
+ *
+ * Return:
+ * true - @policy is the active policy
+ * false - @policy is not the active policy
+ */
+bool ipe_is_active_policy(const struct ipe_policy *policy);
+
+/**
+ * ipe_update_active_policy: Determine if @old is the active policy, and update
+ *			     the active policy if necessary.
+ * @old: The previous policy that the update is trying to replace.
+ * @new: The new policy attempting to replace @old.
+ *
+ * If @old is not the active policy, nothing will be done.
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Invalid Policy
+ */
+int ipe_update_active_policy(const struct ipe_policy *old,
+			     const struct ipe_policy *new);
+
+/**
+ * ipe_activate_policy: Set a specific policy as the active policy.
+ * @pol: The policy to set as the active policy.
+ *
+ * This is only called by the sysctl "ipe.active_policy".
+ *
+ * Return:
+ * 0 - OK
+ * -EINVAL - Policy that is being activated is lower in version than
+ *	     currently running policy.
+ */
+int ipe_activate_policy(const struct ipe_policy *policy);
+
 #endif /* IPE_POLICY_H */
diff --git a/security/ipe/ipe-secfs.c b/security/ipe/ipe-secfs.c
new file mode 100644
index 000000000000..1c9c41e143ab
--- /dev/null
+++ b/security/ipe/ipe-secfs.c
@@ -0,0 +1,814 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+
+#include "ipe.h"
+#include "ipe-parse.h"
+#include "ipe-secfs.h"
+#include "ipe-policy.h"
+#include "ipe-audit.h"
+
+#include <linux/types.h>
+#include <linux/security.h>
+#include <linux/fs.h>
+#include <linux/rcupdate.h>
+#include <linux/mutex.h>
+#include <linux/init.h>
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include <linux/verification.h>
+#include <linux/capability.h>
+
+#define IPE_ROOT "ipe"
+#define IPE_FULL_CONTENT "raw"
+#define IPE_INNER_CONTENT "content"
+#define IPE_POLICIES "policies"
+#define IPE_NEW_POLICY "new_policy"
+#define IPE_DELETE_POLICY "del_policy"
+
+struct ipe_policy_node {
+	u8		*data;
+	size_t		data_len;
+	const u8	*content;
+	size_t		content_size;
+
+	struct ipe_policy *parsed;
+};
+
+/* root directory */
+static struct dentry *ipe_secfs_root __ro_after_init;
+
+/* subdirectory containing policies */
+static struct dentry *ipe_policies_root __ro_after_init;
+
+/* boot policy */
+static struct dentry *boot_policy_node __ro_after_init;
+
+/* top-level policy commands */
+static struct dentry *ipe_new_policy __ro_after_init;
+static struct dentry *ipe_del_policy __ro_after_init;
+
+static ssize_t ipe_secfs_new_policy(struct file *f, const char __user *data,
+				    size_t len, loff_t *offset);
+
+static ssize_t ipe_secfs_del_policy(struct file *f, const char __user *data,
+				    size_t len, loff_t *offset);
+
+static ssize_t ipe_secfs_rd_policy(struct file *f, char __user *data,
+				   size_t len, loff_t *offset);
+
+static ssize_t ipe_secfs_ud_policy(struct file *f, const char __user *data,
+				   size_t len, loff_t *offset);
+
+static ssize_t ipe_secfs_rd_content(struct file *f, char __user *data,
+				    size_t len, loff_t *offset);
+
+const static struct file_operations new_policy_ops = {
+	.write = ipe_secfs_new_policy
+};
+
+const static struct file_operations del_policy_ops = {
+	.write = ipe_secfs_del_policy
+};
+
+const static struct file_operations policy_raw_ops = {
+	.read = ipe_secfs_rd_policy,
+	.write = ipe_secfs_ud_policy
+};
+
+const static struct file_operations policy_content_ops = {
+	.read = ipe_secfs_rd_content
+};
+
+/**
+ * ipe_free_policy_node: Free an ipe_policy_node structure allocated by
+ *			 ipe_alloc_policy_node.
+ * @n: Ipe_policy_node to free
+ */
+static void ipe_free_policy_node(struct ipe_policy_node *n)
+{
+	if (IS_ERR_OR_NULL(n))
+		return;
+
+	ipe_free_policy(n->parsed);
+	kfree(n->data);
+
+	kfree(n);
+}
+
+/**
+ * alloc_callback: Callback given to verify_pkcs7_signature function to set
+ *		   the inner content reference and parse the policy.
+ * @ctx: "ipe_policy_node" to set inner content, size and parsed policy of.
+ * @data: Start of PKCS#7 inner content.
+ * @len: Length of @data.
+ * @asn1hdrlen: Unused.
+ *
+ * Return:
+ * 0 - OK
+ * ERR_PTR(-EBADMSG) - Invalid policy syntax
+ * ERR_PTR(-ENOMEM) - Out of memory
+ */
+static int alloc_callback(void *ctx, const void *data, size_t len,
+			  size_t asn1hdrlen)
+{
+	char *cpy = NULL;
+	struct ipe_policy *pol = NULL;
+	struct ipe_policy_node *n = (struct ipe_policy_node *)ctx;
+
+	n->content = (const u8 *)data;
+	n->content_size = len;
+
+	if (len == 0)
+		return -EBADMSG;
+
+	cpy = kzalloc(len + 1, GFP_KERNEL);
+	if (!cpy)
+		return -ENOMEM;
+
+	(void)strncpy(cpy, data, len);
+
+	pol = ipe_parse_policy(cpy);
+	if (IS_ERR(pol)) {
+		kfree(cpy);
+		return PTR_ERR(pol);
+	}
+
+	n->parsed = pol;
+	kfree(cpy);
+	return 0;
+}
+
+/**
+ * ipe_alloc_policy_node: Allocate a new ipe_policy_node structure.
+ * @data: Raw enveloped PKCS#7 data that represents the policy.
+ * @len: Length of @data.
+ *
+ * Return:
+ * valid ipe_policy_node - OK
+ * ERR_PTR(-EBADMSG) - Invalid policy syntax
+ * ERR_PTR(-ENOMEM) - Out of memory
+ */
+static struct ipe_policy_node *ipe_alloc_policy_node(const u8 *data,
+						     size_t len)
+{
+	int rc = 0;
+	struct ipe_policy_node *node = NULL;
+
+	node = kzalloc(sizeof(*node), GFP_KERNEL);
+	if (!node) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	node->data_len = len;
+	node->data = kmemdup(data, len, GFP_KERNEL);
+	if (!node->data) {
+		rc = -ENOMEM;
+		goto out2;
+	}
+
+	rc = verify_pkcs7_signature(node->content, node->content_size,
+				    node->data, node->data_len, NULL,
+				    VERIFYING_UNSPECIFIED_SIGNATURE,
+				    alloc_callback, node);
+	if (rc != 0)
+		goto out2;
+
+	return node;
+out2:
+	ipe_free_policy_node(node);
+out:
+	return ERR_PTR(rc);
+}
+
+/**
+ * ipe_build_policy_secfs_node: Build a new securityfs node for IPE policies.
+ * @data: Raw enveloped PKCS#7 data that represents the policy.
+ * @len: Length of @data.
+ *
+ * Return:
+ * 0 - OK
+ * -EEXIST - Policy already exists
+ * -EBADMSG - Invalid policy syntax
+ * -ENOMEM - Out of memory
+ */
+int ipe_build_policy_secfs_node(const u8 *data, size_t len)
+{
+	int rc = 0;
+	struct dentry *raw = NULL;
+	struct dentry *root = NULL;
+	struct inode *root_i = NULL;
+	struct dentry *content = NULL;
+	struct crypto_shash *tfm = NULL;
+	struct ipe_policy_node *node = NULL;
+
+	tfm = crypto_alloc_shash("sha1", 0, 0);
+	if (IS_ERR(tfm))
+		goto out;
+
+	node = ipe_alloc_policy_node(data, len);
+	if (IS_ERR(node)) {
+		rc = PTR_ERR(node);
+		goto out2;
+	}
+
+	root = securityfs_create_dir(node->parsed->policy_name,
+				     ipe_policies_root);
+	if (IS_ERR(root)) {
+		rc = PTR_ERR(root);
+		goto out3;
+	}
+
+	root_i = d_inode(root);
+
+	inode_lock(root_i);
+	root_i->i_private = node;
+	ipe_audit_policy_load(node->parsed, node->data, node->data_len, tfm);
+	inode_unlock(root_i);
+
+	raw = securityfs_create_file(IPE_FULL_CONTENT, 0644, root, NULL,
+				     &policy_raw_ops);
+	if (IS_ERR(raw)) {
+		rc = PTR_ERR(raw);
+		goto out4;
+	}
+
+	content = securityfs_create_file(IPE_INNER_CONTENT, 0444, root,
+					 NULL, &policy_content_ops);
+	if (IS_ERR(raw)) {
+		rc = PTR_ERR(raw);
+		goto out5;
+	}
+
+	crypto_free_shash(tfm);
+	return rc;
+out5:
+	securityfs_remove(raw);
+out4:
+	securityfs_remove(root);
+out3:
+	ipe_free_policy_node(node);
+out2:
+	crypto_free_shash(tfm);
+out:
+	return rc;
+}
+
+/**
+ * ipe_secfs_new_policy: Entry point of the securityfs node, "ipe/new_policy".
+ * @f: Unused
+ * @data: Raw enveloped PKCS#7 data that represents the policy.
+ * @len: Length of @data.
+ * @offset: Offset for @data.
+ *
+ * Return:
+ * > 0 - OK
+ * -EEXIST - Policy already exists
+ * -EBADMSG - Invalid policy syntax
+ * -ENOMEM - Out of memory
+ * -EPERM - if a MAC subsystem is enabled, missing CAP_MAC_ADMIN
+ */
+static ssize_t ipe_secfs_new_policy(struct file *f, const char __user *data,
+				    size_t len, loff_t *offset)
+{
+	ssize_t rc = 0;
+	u8 *cpy = NULL;
+	ssize_t written = 0;
+
+	if (!ns_capable(current_user_ns(), CAP_MAC_ADMIN))
+		return -EPERM;
+
+	cpy = kzalloc(len, GFP_KERNEL);
+	if (!cpy) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	written = simple_write_to_buffer(cpy, len, offset, data, len);
+	if (written < 0) {
+		rc = written;
+		goto err;
+	}
+
+	rc = ipe_build_policy_secfs_node(cpy, written);
+err:
+	kfree(cpy);
+	return rc < 0 ? rc : written;
+}
+
+/**
+ * retrieve_backed_dentry: Retrieve a dentry with a backing inode, identified
+ *			   by @name, under @parent.
+ * @name: Name of the dentry under @parent.
+ * @parent: The parent dentry to search under for @name.
+ * @size: Length of @name.
+ *
+ * This takes a reference to the returned dentry. Caller needs to call dput
+ * to drop the reference.
+ *
+ * Return:
+ * valid dentry - OK
+ * ERR_PTR - Error, see lookup_one_len_unlocked
+ * NULL - No backing inode was found
+ */
+static struct dentry *retrieve_backed_dentry(const char *name,
+					     struct dentry *parent,
+					     size_t size)
+{
+	int rc = 0;
+	struct dentry *tmp = NULL;
+
+	tmp = lookup_one_len_unlocked(name, parent, size);
+	if (IS_ERR(tmp)) {
+		rc = PTR_ERR(tmp);
+		goto out;
+	}
+
+	if (!d_really_is_positive(tmp))
+		goto out1;
+
+	return tmp;
+out1:
+	tmp = NULL;
+out:
+	return rc == 0 ? NULL : ERR_PTR(rc);
+}
+
+/**
+ * ipe_secfs_del_policy: Delete a policy indicated by the name provided by
+ *			 @data
+ * @f: Unused.
+ * @data: Buffer containing the policy id to delete.
+ * @len: Length of @data.
+ * @offset: Offset into @data.
+ *
+ * NOTE: Newlines are treated as part of the name, if using echo to test,
+ * use -n to prohibit the silent addition of a newline.
+ *
+ * Return:
+ * > 0 - OK
+ * -ENOMEM - Out of memory
+ * -EPERM - Policy is active
+ * -ENOENT - Policy does not exist
+ * -EPERM - if a MAC subsystem is enabled, missing CAP_MAC_ADMIN
+ * Other - See retrieve_backed_dentry
+ */
+static ssize_t ipe_secfs_del_policy(struct file *f, const char __user *data,
+				    size_t len, loff_t *offset)
+{
+	ssize_t rc = 0;
+	char *id = NULL;
+	ssize_t written = 0;
+	struct dentry *raw = NULL;
+	struct dentry *content = NULL;
+	struct inode *policy_i = NULL;
+	struct dentry *policy_root = NULL;
+	struct inode *policies_root = NULL;
+	const struct ipe_policy *target = NULL;
+
+	if (!ns_capable(current_user_ns(), CAP_MAC_ADMIN))
+		return -EPERM;
+
+	id = kzalloc(len, GFP_KERNEL);
+	if (!id) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	written = simple_write_to_buffer(id, len, offset, data, len);
+	if (written < 0) {
+		rc = written;
+		goto out;
+	}
+
+	policies_root = d_inode(ipe_policies_root);
+
+	policy_root = retrieve_backed_dentry(id, ipe_policies_root, written);
+	if (IS_ERR_OR_NULL(policy_root)) {
+		rc = IS_ERR(policy_root) ? PTR_ERR(policy_root) : -ENOENT;
+		goto out;
+	}
+
+	policy_i = d_inode(policy_root);
+
+	/* if the found dentry matches boot policy, fail */
+	if (boot_policy_node == policy_root) {
+		rc = -EACCES;
+		goto out1;
+	}
+
+	target = ((struct ipe_policy_node *)policy_i->i_private)->parsed;
+
+	/* fail if it's the active policy */
+	if (ipe_is_active_policy(target)) {
+		rc = -EPERM;
+		goto out1;
+	}
+
+	raw = retrieve_backed_dentry(IPE_FULL_CONTENT, policy_root,
+				     strlen(IPE_FULL_CONTENT));
+	if (IS_ERR_OR_NULL(raw)) {
+		rc = IS_ERR(raw) ? PTR_ERR(raw) : -ENOENT;
+		goto out1;
+	}
+
+	content = retrieve_backed_dentry(IPE_INNER_CONTENT, policy_root,
+					 strlen(IPE_INNER_CONTENT));
+	if (IS_ERR_OR_NULL(content)) {
+		rc = IS_ERR(content) ? PTR_ERR(content) : -ENOENT;
+		goto out2;
+	}
+
+	inode_lock(policies_root);
+	ipe_free_policy_node(policy_i->i_private);
+	policy_i->i_private = NULL;
+	inode_unlock(policies_root);
+
+	dput(raw);
+	dput(content);
+	dput(policy_root);
+	securityfs_remove(raw);
+	securityfs_remove(content);
+	securityfs_remove(policy_root);
+
+	kfree(id);
+	return written;
+out2:
+	dput(raw);
+out1:
+	dput(policy_root);
+out:
+	kfree(id);
+	return rc;
+}
+
+/**
+ * ipe_secfs_rd_policy: Read the raw content (full enveloped PKCS7) data of
+ *			the policy stored within the file's parent inode.
+ * @f: File representing the securityfs entry.
+ * @data: User mode buffer to place the raw pkcs7.
+ * @len: Length of @data.
+ * @offset: Offset into @data.
+ *
+ * Return:
+ * > 0 - OK
+ * -ENOMEM - Out of memory
+ */
+static ssize_t ipe_secfs_rd_policy(struct file *f, char __user *data,
+				   size_t size, loff_t *offset)
+{
+	ssize_t rc = 0;
+	size_t avail = 0;
+	u8 *buffer = NULL;
+	struct inode *root = NULL;
+	const struct ipe_policy_node *node = NULL;
+
+	root = d_inode(f->f_path.dentry->d_parent);
+
+	inode_lock_shared(root);
+	node = (const struct ipe_policy_node *)root->i_private;
+
+	avail = node->data_len;
+	buffer = kmemdup(node->data, avail, GFP_KERNEL);
+	if (!buffer) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	rc = simple_read_from_buffer(data, size, offset, buffer, avail);
+cleanup:
+	inode_unlock_shared(root);
+
+	return rc;
+}
+
+/**
+ * ipe_secfs_ud_policy: Update a policy in place with a new PKCS7 policy.
+ * @f: File representing the securityfs entry.
+ * @data: Buffer user mode to place the raw pkcs7.
+ * @len: Length of @data.
+ * @offset: Offset into @data.
+ *
+ * Return:
+ * 0 - OK
+ * -EBADMSG - Invalid policy format
+ * -ENOMEM - Out of memory
+ * -EPERM - if a MAC subsystem is enabled, missing CAP_MAC_ADMIN
+ * -EINVAL - Incorrect policy name for this node, or version is < current
+ */
+static ssize_t ipe_secfs_ud_policy(struct file *f, const char __user *data,
+				   size_t len, loff_t *offset)
+{
+	ssize_t rc = 0;
+	u8 *cpy = NULL;
+	ssize_t written = 0;
+	struct inode *root = NULL;
+	struct crypto_shash *tfm = NULL;
+	struct ipe_policy_node *new = NULL;
+	struct ipe_policy_node *old = NULL;
+
+	if (!ns_capable(current_user_ns(), CAP_MAC_ADMIN))
+		return -EPERM;
+
+	cpy = kzalloc(len, GFP_KERNEL);
+	if (!cpy) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	written = simple_write_to_buffer(cpy, len, offset, data, len);
+	if (written < 0) {
+		rc = written;
+		goto out;
+	}
+
+	new = ipe_alloc_policy_node(cpy, len);
+	if (IS_ERR(new)) {
+		rc = PTR_ERR(new);
+		goto out;
+	}
+
+	tfm = crypto_alloc_shash("sha1", 0, 0);
+	if (IS_ERR(tfm))
+		goto out2;
+
+	root = d_inode(f->f_path.dentry->d_parent);
+	inode_lock(root);
+
+	old = (struct ipe_policy_node *)root->i_private;
+
+	if (strcmp(old->parsed->policy_name, new->parsed->policy_name)) {
+		rc = -EINVAL;
+		goto out3;
+	}
+
+	if (!ipe_is_valid_policy(old->parsed, new->parsed)) {
+		rc = -EINVAL;
+		goto out3;
+	}
+
+	rc = ipe_update_active_policy(old->parsed, new->parsed);
+	if (rc != 0)
+		goto out3;
+
+	ipe_audit_policy_load(new->parsed, new->data, new->data_len, tfm);
+	swap(root->i_private, new);
+
+	inode_unlock(root);
+	kfree(cpy);
+	ipe_free_policy_node(new);
+	crypto_free_shash(tfm);
+
+	return written;
+out3:
+	inode_unlock(root);
+	ipe_free_policy_node(new);
+out2:
+	crypto_free_shash(tfm);
+out:
+	kfree(cpy);
+	return rc;
+}
+
+/**
+ * ipe_secfs_rd_content: Read the inner content of the enveloped PKCS7 data,
+ *			 representing the IPE policy.
+ * @f: File representing the securityfs entry.
+ * @data: User mode buffer to place the inner content of the pkcs7 data.
+ * @len: Length of @data.
+ * @offset: Offset into @data.
+ *
+ * Return:
+ * > 0 - OK
+ * -ENOMEM - Out of memory
+ */
+static ssize_t ipe_secfs_rd_content(struct file *f, char __user *data,
+				    size_t size, loff_t *offset)
+{
+	ssize_t rc = 0;
+	size_t avail = 0;
+	u8 *buffer = NULL;
+	struct inode *root = NULL;
+	const struct ipe_policy_node *node = NULL;
+
+	root = d_inode(f->f_path.dentry->d_parent);
+
+	inode_lock(root);
+	node = (const struct ipe_policy_node *)root->i_private;
+
+	avail = node->content_size;
+	buffer = kmemdup(node->content, avail, GFP_KERNEL);
+	if (!buffer) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	rc = simple_read_from_buffer(data, size, offset, buffer, avail);
+cleanup:
+	inode_unlock(root);
+
+	return rc;
+}
+
+/**
+ * ipe_build_secfs_root: Build the root of securityfs for IPE.
+ *
+ * Return:
+ * 0 - OK
+ * !0 - See securityfs_create_dir and securityfs_create_file
+ */
+int __init ipe_build_secfs_root(void)
+{
+	int rc = 0;
+	struct dentry *new = NULL;
+	struct dentry *del = NULL;
+	struct dentry *root = NULL;
+	struct dentry *policies = NULL;
+
+	root = securityfs_create_dir(IPE_ROOT, NULL);
+	if (IS_ERR(root)) {
+		rc = PTR_ERR(root);
+		goto out;
+	}
+
+	new = securityfs_create_file(IPE_NEW_POLICY, 0644, root, NULL,
+				     &new_policy_ops);
+	if (IS_ERR(new)) {
+		rc = PTR_ERR(new);
+		goto out1;
+	}
+
+	del = securityfs_create_file(IPE_DELETE_POLICY, 0644, root, NULL,
+				     &del_policy_ops);
+	if (IS_ERR(del)) {
+		rc = PTR_ERR(del);
+		goto out2;
+	}
+
+	policies = securityfs_create_dir(IPE_POLICIES, root);
+	if (IS_ERR(policies)) {
+		rc = PTR_ERR(policies);
+		goto out3;
+	}
+
+	ipe_secfs_root = root;
+	ipe_new_policy = new;
+	ipe_del_policy = del;
+	ipe_policies_root = policies;
+
+	return rc;
+
+out3:
+	securityfs_remove(del);
+out2:
+	securityfs_remove(new);
+out1:
+	securityfs_remove(root);
+out:
+	return rc;
+}
+
+/**
+ * ipe_build_secfs_boot_node: Build a policy node for IPE's boot policy.
+ *
+ * This differs from the normal policy nodes, as the IPE boot policy is
+ * read only.
+ *
+ * Return:
+ * 0 - OK
+ * !0 - See securityfs_create_dir and securityfs_create_file
+ */
+static int __init ipe_build_secfs_boot_node(void)
+{
+	int rc = 0;
+	char *cpy = NULL;
+	struct dentry *raw = NULL;
+	struct inode *raw_i = NULL;
+	struct dentry *root = NULL;
+	struct dentry *content = NULL;
+	struct ipe_policy *parsed = NULL;
+	struct ipe_policy_node *node = NULL;
+
+	if (!ipe_boot_policy)
+		return 0;
+
+	node = kzalloc(sizeof(*node), GFP_KERNEL);
+	if (!node) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	cpy = kstrdup(ipe_boot_policy, GFP_KERNEL);
+	if (!cpy) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	parsed = ipe_parse_policy(cpy);
+	if (IS_ERR(parsed)) {
+		rc = PTR_ERR(parsed);
+		goto out2;
+	}
+
+	node->content = ipe_boot_policy;
+	node->content_size = strlen(cpy);
+	node->parsed = parsed;
+
+	root = securityfs_create_dir(node->parsed->policy_name,
+				     ipe_policies_root);
+	if (IS_ERR(root)) {
+		rc = PTR_ERR(root);
+		goto out2;
+	}
+
+	raw_i = d_inode(root);
+
+	inode_lock(raw_i);
+	raw_i->i_private = node;
+	inode_unlock(raw_i);
+
+	content = securityfs_create_file(IPE_INNER_CONTENT, 0444, root, NULL,
+					 &policy_content_ops);
+	if (IS_ERR(raw)) {
+		rc = PTR_ERR(raw);
+		goto out3;
+	}
+
+	boot_policy_node = root;
+	rc = ipe_activate_policy(node->parsed);
+	return rc;
+
+out3:
+	securityfs_remove(root);
+out2:
+	ipe_free_policy(parsed);
+out:
+	kfree(cpy);
+	kfree(node);
+	return rc;
+}
+
+/**
+ * ipe_set_active_policy: Set the policy identified by @id as the active
+ *			  policy.
+ * @id: Policy id represnting the policy to activate.
+ * @id_len: Length of @id.
+ *
+ * Return:
+ * 0 - OK
+ * -ENOENT - Policy identified by @id does not exist
+ * -EINVAL - Policy that is being activated is lower in version than
+ *	     currently running policy.
+ * Other - See retrieve_backed_dentry
+ */
+int ipe_set_active_policy(const char *id, size_t id_len)
+{
+	int rc = 0;
+	struct dentry *policy_root = NULL;
+	const struct ipe_policy_node *ref = NULL;
+
+	policy_root = retrieve_backed_dentry(id, ipe_policies_root, id_len);
+	if (IS_ERR_OR_NULL(policy_root))
+		return IS_ERR(policy_root) ? PTR_ERR(policy_root) : -ENOENT;
+
+	inode_lock_shared(d_inode(policy_root));
+
+	ref = (const struct ipe_policy_node *)d_inode(policy_root)->i_private;
+	rc = ipe_activate_policy(ref->parsed);
+
+	inode_unlock_shared(d_inode(policy_root));
+	dput(policy_root);
+
+	return rc;
+}
+
+/**
+ * ipe_securityfs_init: Initialize IPE's securityfs entries.
+ *
+ * This is called after the lsm initialization.
+ *
+ * Return:
+ * 0 - OK
+ * !0 - Error
+ */
+int __init ipe_securityfs_init(void)
+{
+	int rc = 0;
+
+	rc = ipe_build_secfs_root();
+	if (rc != 0)
+		goto err;
+
+	rc = ipe_build_secfs_boot_node();
+	if (rc != 0)
+		panic("IPE failed to initialize the boot policy: %d", rc);
+
+	return rc;
+err:
+	pr_err("failed to initialize secfs: %d", -rc);
+	return rc;
+}
+
+core_initcall(ipe_securityfs_init);
diff --git a/security/ipe/ipe-secfs.h b/security/ipe/ipe-secfs.h
new file mode 100644
index 000000000000..714ae70a4c8e
--- /dev/null
+++ b/security/ipe/ipe-secfs.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+#include <linux/types.h>
+
+#include "ipe-policy.h"
+
+#ifndef IPE_SECFS_H
+#define IPE_SECFS_H
+
+/**
+ * ipe_set_active_policy: Set the policy identified by @id as the active
+ *			  policy.
+ * @id: Policy id represnting the policy to activate.
+ * @id_len: Length of @id.
+ *
+ * Return:
+ * 0 - OK
+ * -ENOENT - Policy identified by @id does not exist
+ * Other - See retrieve_backed_dentry
+ */
+int ipe_set_active_policy(const char *id, size_t id_len);
+
+#endif /* IPE_SECFS_H */
diff --git a/security/ipe/ipe-sysfs.c b/security/ipe/ipe-sysfs.c
index c97685a25b6a..a3c998da69da 100644
--- a/security/ipe/ipe-sysfs.c
+++ b/security/ipe/ipe-sysfs.c
@@ -5,6 +5,7 @@
 
 #include "ipe.h"
 #include "ipe-audit.h"
+#include "ipe-secfs.h"
 
 #include <linux/sysctl.h>
 #include <linux/fs.h>
@@ -45,6 +46,73 @@ static int ipe_switch_mode(struct ctl_table *table, int write,
 
 #endif /* CONFIG_SECURITY_IPE_PERMISSIVE_SWITCH */
 
+#ifdef CONFIG_SECURITYFS
+
+/**
+ * ipe_switch_active_policy: Handler to switch the policy IPE is enforcing.
+ * @table: Sysctl table entry from the variable, sysctl_table.
+ * @write: Integer indicating whether this is a write or a read.
+ * @buffer: Data passed to sysctl. This is the policy id to activate,
+ *	    for this function.
+ * @lenp: Pointer to the size of @buffer.
+ * @ppos: Offset into @buffer.
+ *
+ * This wraps proc_dointvec_minmax, and if there's a change, emits an
+ * audit event.
+ *
+ * Return:
+ * 0 - OK
+ * -ENOMEM - Out of memory
+ * -ENOENT - Policy identified by @id does not exist
+ * Other - See proc_dostring and retrieve_backed_dentry
+ */
+static int ipe_switch_active_policy(struct ctl_table *table, int write,
+				    void __user *buffer, size_t *lenp,
+				    loff_t *ppos)
+{
+	int rc = 0;
+	char *id = NULL;
+	size_t size = 0;
+
+	if (write) {
+		id = kzalloc((*lenp) + 1, GFP_KERNEL);
+		if (!id)
+			return -ENOMEM;
+
+		table->data = id;
+		table->maxlen = (*lenp) + 1;
+
+		rc = proc_dostring(table, write, buffer, lenp, ppos);
+		if (rc != 0)
+			goto out;
+
+		rc = ipe_set_active_policy(id, strlen(id));
+	} else {
+		rcu_read_lock();
+		size = strlen(rcu_dereference(ipe_active_policy)->policy_name);
+		rcu_read_unlock();
+
+		id = kzalloc(size + 1, GFP_KERNEL);
+		if (!id)
+			return -ENOMEM;
+
+		rcu_read_lock();
+		strncpy(id, rcu_dereference(ipe_active_policy)->policy_name,
+			size);
+		rcu_read_unlock();
+
+		table->data = id;
+		table->maxlen = size;
+
+		rc = proc_dostring(table, write, buffer, lenp, ppos);
+	}
+out:
+	kfree(id);
+	return rc;
+}
+
+#endif /* CONFIG_SECURITYFS */
+
 static struct ctl_table_header *sysctl_header;
 
 static const struct ctl_path sysctl_path[] = {
@@ -75,6 +143,24 @@ static struct ctl_table sysctl_table[] = {
 		.extra1 = SYSCTL_ZERO,
 		.extra2 = SYSCTL_ONE,
 	},
+#ifdef CONFIG_SECURITYFS
+	{
+		.procname = "strict_parse",
+		.data = &strict_parse,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = SYSCTL_ZERO,
+		.extra2 = SYSCTL_ONE,
+	},
+	{
+		.procname = "active_policy",
+		.data = NULL,
+		.maxlen = 0,
+		.mode = 0644,
+		.proc_handler = ipe_switch_active_policy,
+	},
+#endif /* CONFIG_SECURITYFS */
 	{}
 	/* TODO: Active Policy Selector */
 };
diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c
index 0c30d7c629c9..4642a0da57e5 100644
--- a/security/ipe/ipe.c
+++ b/security/ipe/ipe.c
@@ -6,6 +6,7 @@
 #include "ipe.h"
 #include "ipe-policy.h"
 #include "ipe-hooks.h"
+#include "ipe-secfs.h"
 #include "ipe-sysfs.h"
 
 #include <linux/module.h>
@@ -97,3 +98,15 @@ MODULE_PARM_DESC(enforce, "enforce/permissive mode switch");
 int success_audit;
 module_param(success_audit, int, 0644);
 MODULE_PARM_DESC(success_audit, "audit message on allow");
+
+/**
+ * strict_parse: Kernel command line parameter to enable strict parsing of
+ *		 IPE policies - causing unrecognized properties to fail
+ *		 parsing. This breaks backwards compatibility of IPE policies,
+ *		 when enabled.
+ *
+ * This is also controlled by the sysctl, "ipe.strict_parse".
+ */
+int strict_parse;
+module_param(strict_parse, int, 0644);
+MODULE_PARM_DESC(strict_parse, "parse using strict semantics");
diff --git a/security/ipe/ipe.h b/security/ipe/ipe.h
index 52e5ea0ccaef..c016b57aa70b 100644
--- a/security/ipe/ipe.h
+++ b/security/ipe/ipe.h
@@ -16,5 +16,6 @@
 
 extern int enforce;
 extern int success_audit;
+extern int strict_parse;
 
 #endif /* IPE_H */
-- 
2.26.0