[RFC,v2,03/12] security: add ipe lsm policy parser and policy loading
diff mbox series

Message ID 20200406221439.1469862-4-deven.desai@linux.microsoft.com
State New
Headers show
Series
  • Integrity Policy Enforcement LSM (IPE)
Related show

Commit Message

Deven Bowers April 6, 2020, 10:14 p.m. UTC
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

Comments

Jann Horn April 7, 2020, 3:39 p.m. UTC | #1
On Tue, Apr 7, 2020 at 12:14 AM <deven.desai@linux.microsoft.com> wrote:
[...]
> Adds the policy parser and the policy loading to IPE, along with the
> related sysfs and securityfs entries.
[...]
> diff --git a/security/ipe/ipe-parse.c b/security/ipe/ipe-parse.c
[...]
> +/* 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;
> +};
> +
[...]
> +/**
> + * 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;

What is this assignment supposed to do?

> +}
[...]
> diff --git a/security/ipe/ipe-policy.c b/security/ipe/ipe-policy.c
[...]
> +/**
> + * 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();

You're not actually accessing the pointer, so you can use rcu_access_pointer()
and get rid of the rcu_read_lock()/rcu_read_unlock(). Then this helper turns
into a one-liner.

> +       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)

This should be rcu_access_pointer().

> +               return 0;
[...]
> +}
[...]
> diff --git a/security/ipe/ipe-secfs.c b/security/ipe/ipe-secfs.c
[...]
> +/**
> + * 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);

Shouldn't this just be memcpy()?

> +       pol = ipe_parse_policy(cpy);
> +       if (IS_ERR(pol)) {
> +               kfree(cpy);
> +               return PTR_ERR(pol);
> +       }
> +
> +       n->parsed = pol;
> +       kfree(cpy);
> +       return 0;
> +}
[...]
> +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;

Use file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN) instead, both here and
elsewhere.

> +       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;
> +       }

This should probably be memdup_user() instead of
kzalloc()+simple_write_to_buffer()?

> +       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;
> +       }

You could just "return tmp;" here.

> +
> +       if (!d_really_is_positive(tmp))
> +               goto out1;

And here "return NULL;".

> +       return tmp;
> +out1:
> +       tmp = NULL;

This just sets a variable that is never read again to 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;
> +       }

Why can it not become the active policy after this check?

> +       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);

Same thing as in ipe_secfs_rd_content(): simple_read_from_buffer() needlessly
within locked section, buffer not freed.

> +
> +       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;
> +       }

You'd probably be better off just doing memdup_user() here.
simple_write_to_buffer() only makes sense if you have a buffer that can be
continuously updated with multiple writes.

> +       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;
> +}
[...]
> +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);

Why are you nod doing the simple_read_from_buffer() after inode_unlock()?
The way you're doing it now, there isn't really a point in the kmemdup() at
all...
Also, you'll have to free the buffer before returning.

> +       return rc;
> +}
[...]
> diff --git a/security/ipe/ipe-sysfs.c b/security/ipe/ipe-sysfs.c
[...]
> +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);

Can't `ipe_active_policy` be NULL here?

> +               rcu_read_unlock();
> +
> +               id = kzalloc(size + 1, GFP_KERNEL);

The `+ 1` seems unnecessary.

> +               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 */
[...]
> diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c
[...]
> +
> +/**
> + * 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.

I guess the backwards compatibility stuff is referring to an out-of-tree version
of this series that you've already shipped?

> + * This is also controlled by the sysctl, "ipe.strict_parse".
> + */

(Also, same thing as in the other patch re sysctls and kernel command line
parameters for the same feature.)
Deven Bowers April 9, 2020, 4:41 p.m. UTC | #2
On 4/7/2020 8:39 AM, Jann Horn wrote:
> On Tue, Apr 7, 2020 at 12:14 AM<deven.desai@linux.microsoft.com>  wrote:
> [...]
>> Adds the policy parser and the policy loading to IPE, along with the
>> related sysfs and securityfs entries.
> [...]
>> diff --git a/security/ipe/ipe-parse.c b/security/ipe/ipe-parse.c
> [...]
>> +/* 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;
>> +};
>> +
> [...]
>> +/**
>> + * 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;
> What is this assignment supposed to do?

Apologies, it's a useless statement. I occasionally forget to strip this
pattern throughout my code. It's supposed to help avoid double-free
but ultimately it's useless.

>> +}
> [...]
>> diff --git a/security/ipe/ipe-policy.c b/security/ipe/ipe-policy.c
> [...]
>> +/**
>> + * 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();
> You're not actually accessing the pointer, so you can use rcu_access_pointer()
> and get rid of the rcu_read_lock()/rcu_read_unlock(). Then this helper turns
> into a one-liner.
Got it. There's several places it looks like I did this. I'll fix it all.
>> +       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)
> This should be rcu_access_pointer().
Got it.
>> +               return 0;
> [...]
>> +}
> [...]
>> diff --git a/security/ipe/ipe-secfs.c b/security/ipe/ipe-secfs.c
> [...]
>> +/**
>> + * 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);
> Shouldn't this just be memcpy()?
Good point. It won't ever be null terminated because of the
signature format, so it's effectively memcpy. I'll change it.
>> +       pol = ipe_parse_policy(cpy);
>> +       if (IS_ERR(pol)) {
>> +               kfree(cpy);
>> +               return PTR_ERR(pol);
>> +       }
>> +
>> +       n->parsed = pol;
>> +       kfree(cpy);
>> +       return 0;
>> +}
> [...]
>> +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;
> Use file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN) instead, both here and
> elsewhere.
Thanks.
>> +       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;
>> +       }
> This should probably be memdup_user() instead of
> kzalloc()+simple_write_to_buffer()?
I wasn't aware of memdup_user. I'll change it next iteration.
>> +       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;
>> +       }
> You could just "return tmp;" here.
>
>> +
>> +       if (!d_really_is_positive(tmp))
>> +               goto out1;
> And here "return NULL;".
>
>> +       return tmp;
>> +out1:
>> +       tmp = NULL;
> This just sets a variable that is never read again to NULL?
Thanks, I'll fix these up.
>> +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;
>> +       }
> Why can it not become the active policy after this check?
Ah, good catch. (The test suite just caught this as well). So this needs to
be synchronized with the active policy  functions. I'm pretty sure I should
just move the policy lock from the activation functions to be locked &
unlocked here. That'll enforce that both are checked in blocking sections.
>> +       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);
> Same thing as in ipe_secfs_rd_content(): simple_read_from_buffer() needlessly
> within locked section, buffer not freed.
I don't know how I missed such an obvious memleak. I'll remove the 
unnecessary
kmemdup.
>> +
>> +       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;
>> +       }
> You'd probably be better off just doing memdup_user() here.
> simple_write_to_buffer() only makes sense if you have a buffer that can be
> continuously updated with multiple writes.
Thanks, I'll fix it.
>> +       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;
>> +}
> [...]
>> +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);
> Why are you nod doing the simple_read_from_buffer() after inode_unlock()?
> The way you're doing it now, there isn't really a point in the kmemdup() at
> all...
> Also, you'll have to free the buffer before returning.
I don't know how I missed such an obvious memleak. I'll remove the 
unnecessary
kmemdup.
>
>> +       return rc;
>> +}
> [...]
>> diff --git a/security/ipe/ipe-sysfs.c b/security/ipe/ipe-sysfs.c
> [...]
>> +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);
> Can't `ipe_active_policy` be NULL here?
>
>> +               rcu_read_unlock();
>> +
>> +               id = kzalloc(size + 1, GFP_KERNEL);
> The `+ 1` seems unnecessary.
This is actually necessary. size would point to the string without 
nullterm. strncpy
below is due to if the active policy changes: if it's bigger, then we 
truncate, if it's
smaller, we'll exit early. Either way, it's guaranteed to be null 
terminated.

Later, in proc_dostring, strlen is called, and as a result KASAN catches 
an OOB
read without the +1.
>
>> +               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 */
> [...]
>> diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c
> [...]
>> +
>> +/**
>> + * 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.
> I guess the backwards compatibility stuff is referring to an out-of-tree version
> of this series that you've already shipped?
Actually no. The backwards compatibility stuff is intended to help 
divorcing kernel updates from policy updates.
At the moment, the default behavior of IPE is to ignore any lines that 
do not parse successfully. This allows policies
written for newer versions of IPE to parse and apply successfully. Thus, 
policy can be updated without a dependency
on the kernel being updated.

If that behavior isn't desirable, then you can enable this sysctl / 
kernel command line parameter to cause the
unrecognized lines to error fatally.  Operationally, I see merits to 
both methods, at the cost of what boils down
to an if statement, so I kept this as a configurable option.
>
>> + * This is also controlled by the sysctl, "ipe.strict_parse".
>> + */
> (Also, same thing as in the other patch re sysctls and kernel command line
> parameters for the same feature.)
Yes, I am going to strip out all this.

Patch
diff mbox series

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 */