diff mbox series

[RFC,v4,1/2] selinux: encapsulate policy state, refactor policy load

Message ID 20200805155240.26473-1-stephen.smalley.work@gmail.com (mailing list archive)
State Superseded
Delegated to: Paul Moore
Headers show
Series [RFC,v4,1/2] selinux: encapsulate policy state, refactor policy load | expand

Commit Message

Stephen Smalley Aug. 5, 2020, 3:52 p.m. UTC 
Encapsulate the policy state in its own structure (struct
selinux_policy) that is separately allocated but referenced from the
selinux_ss structure.  The policy state includes the SID table
(particularly the context structures), the policy database, and the
mapping between the kernel classes/permissions and the policy values.
Refactor the security server portion of the policy load logic to
cleanly separate loading of the new structures from committing the new
policy.  Unify the initial policy load and reload code paths as much
as possible, avoiding duplicated code.  Make sure we are taking the
policy read-lock prior to any dereferencing of the policy.  Move the
copying of the policy capability booleans into the state structure
outside of the policy write-lock because they are separate from the
policy and are read outside of any policy lock; possibly they should
be using at least READ_ONCE/WRITE_ONCE or smp_load_acquire/store_release.
Restore the load mutex that was previously removed by
commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy")
to make explicit the exclusion even though it is currently redundant
with the fsi->mutex held by selinuxfs; this makes clear that we do
not need to take the policy read-lock across sidtab_convert() and will
be useful in the future for lockdep checking.

These changes simplify the policy loading logic, reduce the size of
the critical section while holding the policy write-lock, and should
facilitate future changes to e.g. refactor the entire policy reload
logic including the selinuxfs code to make the updating of the policy
and the selinuxfs directory tree atomic and/or to convert the policy
read-write lock to RCU.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
---
v4 does not take the policy read-lock across sidtab_convert() and
therefore does not require changing allocations by it to be atomic
or dropping the cond_resched() call.  To make obvious that taking
the policy read-lock is not necessary in security_load_policy(), restore
the load mutex to security_load_policy() that was removed back in
commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy").
However, since we have refactored security_load_policy() in this change
to split out selinux_policy_commit(), we need to take the mutex in
security_load_policy() and release it in selinux_policy_commit().

 security/selinux/ss/services.c | 403 +++++++++++++++++----------------
 security/selinux/ss/services.h |  11 +-
 2 files changed, 220 insertions(+), 194 deletions(-)

Comments

Paul Moore Aug. 7, 2020, 3:41 a.m. UTC | #1 
On Wed, Aug 5, 2020 at 11:52 AM Stephen Smalley
<stephen.smalley.work@gmail.com> wrote:
>
> Encapsulate the policy state in its own structure (struct
> selinux_policy) that is separately allocated but referenced from the
> selinux_ss structure.  The policy state includes the SID table
> (particularly the context structures), the policy database, and the
> mapping between the kernel classes/permissions and the policy values.
> Refactor the security server portion of the policy load logic to
> cleanly separate loading of the new structures from committing the new
> policy.  Unify the initial policy load and reload code paths as much
> as possible, avoiding duplicated code.  Make sure we are taking the
> policy read-lock prior to any dereferencing of the policy.  Move the
> copying of the policy capability booleans into the state structure
> outside of the policy write-lock because they are separate from the
> policy and are read outside of any policy lock; possibly they should
> be using at least READ_ONCE/WRITE_ONCE or smp_load_acquire/store_release.
> Restore the load mutex that was previously removed by
> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy")
> to make explicit the exclusion even though it is currently redundant
> with the fsi->mutex held by selinuxfs; this makes clear that we do
> not need to take the policy read-lock across sidtab_convert() and will
> be useful in the future for lockdep checking.
>
> These changes simplify the policy loading logic, reduce the size of
> the critical section while holding the policy write-lock, and should
> facilitate future changes to e.g. refactor the entire policy reload
> logic including the selinuxfs code to make the updating of the policy
> and the selinuxfs directory tree atomic and/or to convert the policy
> read-write lock to RCU.
>
> Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> ---
> v4 does not take the policy read-lock across sidtab_convert() and
> therefore does not require changing allocations by it to be atomic
> or dropping the cond_resched() call.  To make obvious that taking
> the policy read-lock is not necessary in security_load_policy(), restore
> the load mutex to security_load_policy() that was removed back in
> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy").
> However, since we have refactored security_load_policy() in this change
> to split out selinux_policy_commit(), we need to take the mutex in
> security_load_policy() and release it in selinux_policy_commit().

I'm not in love with the idea of splitting the lock/unlock across
different functions, more below in the relevant code section.

>  security/selinux/ss/services.c | 403 +++++++++++++++++----------------
>  security/selinux/ss/services.h |  11 +-
>  2 files changed, 220 insertions(+), 194 deletions(-)

...


> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> index 9e76a80db6e1..6dea93fac9e2 100644
> --- a/security/selinux/ss/services.c
> +++ b/security/selinux/ss/services.c
> @@ -2115,11 +2126,73 @@ static void security_load_policycaps(struct selinux_state *state)
>                         pr_info("SELinux:  unknown policy capability %u\n",
>                                 i);
>         }
> +
> +       read_unlock(&state->ss->policy_rwlock);
>  }
>
>  static int security_preserve_bools(struct selinux_state *state,
>                                    struct policydb *newpolicydb);
>
> +static void selinux_policy_free(struct selinux_policy *policy)
> +{
> +       if (!policy)
> +               return;
> +
> +       policydb_destroy(&policy->policydb);
> +       sidtab_destroy(&policy->sidtab);
> +       kfree(policy->map.mapping);
> +       kfree(policy);
> +}
> +
> +static void selinux_policy_commit(struct selinux_state *state,
> +                               struct selinux_policy *newpolicy)
> +{
> +       struct selinux_policy *oldpolicy;
> +       u32 seqno;
> +
> +       lockdep_assert_held(&state->ss->load_mutex);
> +
> +       /* If switching between different policy types, log MLS status */
> +       oldpolicy = state->ss->policy;
> +       if (oldpolicy) {
> +               if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
> +                       pr_info("SELinux: Disabling MLS support...\n");
> +               else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
> +                       pr_info("SELinux: Enabling MLS support...\n");
> +       }
> +
> +       /* Install the new policy. */
> +       write_lock_irq(&state->ss->policy_rwlock);
> +       state->ss->policy = newpolicy;
> +       seqno = ++state->ss->latest_granting;
> +       write_unlock_irq(&state->ss->policy_rwlock);
> +
> +       /* Load the policycaps from the new policy */
> +       security_load_policycaps(state);
> +
> +       if (!selinux_initialized(state)) {
> +               /*
> +                * After first policy load, the security server is
> +                * marked as initialized and ready to handle requests and
> +                * any objects created prior to policy load are then labeled.
> +                */
> +               selinux_mark_initialized(state);
> +               mutex_unlock(&state->ss->load_mutex);
> +               selinux_complete_init();
> +       } else
> +               mutex_unlock(&state->ss->load_mutex);
> +
> +       /* Free the old policy */
> +       selinux_policy_free(oldpolicy);
> +
> +       /* Flush external caches and notify userspace of policy load */
> +       avc_ss_reset(state->avc, seqno);
> +       selnl_notify_policyload(seqno);
> +       selinux_status_update_policyload(state, seqno);
> +       selinux_netlbl_cache_invalidate();
> +       selinux_xfrm_notify_policyload();
> +}

I can somewhat understand if you don't want to have all the old policy
cleanup, reset, and notify code in security_load_policy(), but I
really dislike that the mutex lock/unlock is split across the two
functions.

What if selinux_policy_commit() returned oldpolicy on success and we
created a new function, selinux_policy_retire() (name?), that would be
called from security_load_policy and could handle the cleanup, reset,
and notify code.  The mutex unlock could happen between the calls to
selinux_policy_commit() and selinux_policy_retire()?

I'm open to other ideas as well.
Stephen Smalley Aug. 7, 2020, 12:20 p.m. UTC | #2 
On 8/6/20 11:41 PM, Paul Moore wrote:

> On Wed, Aug 5, 2020 at 11:52 AM Stephen Smalley
> <stephen.smalley.work@gmail.com> wrote:
>> Encapsulate the policy state in its own structure (struct
>> selinux_policy) that is separately allocated but referenced from the
>> selinux_ss structure.  The policy state includes the SID table
>> (particularly the context structures), the policy database, and the
>> mapping between the kernel classes/permissions and the policy values.
>> Refactor the security server portion of the policy load logic to
>> cleanly separate loading of the new structures from committing the new
>> policy.  Unify the initial policy load and reload code paths as much
>> as possible, avoiding duplicated code.  Make sure we are taking the
>> policy read-lock prior to any dereferencing of the policy.  Move the
>> copying of the policy capability booleans into the state structure
>> outside of the policy write-lock because they are separate from the
>> policy and are read outside of any policy lock; possibly they should
>> be using at least READ_ONCE/WRITE_ONCE or smp_load_acquire/store_release.
>> Restore the load mutex that was previously removed by
>> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy")
>> to make explicit the exclusion even though it is currently redundant
>> with the fsi->mutex held by selinuxfs; this makes clear that we do
>> not need to take the policy read-lock across sidtab_convert() and will
>> be useful in the future for lockdep checking.
>>
>> These changes simplify the policy loading logic, reduce the size of
>> the critical section while holding the policy write-lock, and should
>> facilitate future changes to e.g. refactor the entire policy reload
>> logic including the selinuxfs code to make the updating of the policy
>> and the selinuxfs directory tree atomic and/or to convert the policy
>> read-write lock to RCU.
>>
>> Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
>> ---
>> v4 does not take the policy read-lock across sidtab_convert() and
>> therefore does not require changing allocations by it to be atomic
>> or dropping the cond_resched() call.  To make obvious that taking
>> the policy read-lock is not necessary in security_load_policy(), restore
>> the load mutex to security_load_policy() that was removed back in
>> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy").
>> However, since we have refactored security_load_policy() in this change
>> to split out selinux_policy_commit(), we need to take the mutex in
>> security_load_policy() and release it in selinux_policy_commit().
> I'm not in love with the idea of splitting the lock/unlock across
> different functions, more below in the relevant code section.


Me either, but I see no alternative other than taking/releasing the 
mutex in selinuxfs, at which point it is truly no different than 
fsi->mutex.

> I can somewhat understand if you don't want to have all the old policy
> cleanup, reset, and notify code in security_load_policy(), but I
> really dislike that the mutex lock/unlock is split across the two
> functions.
>
> What if selinux_policy_commit() returned oldpolicy on success and we
> created a new function, selinux_policy_retire() (name?), that would be
> called from security_load_policy and could handle the cleanup, reset,
> and notify code.  The mutex unlock could happen between the calls to
> selinux_policy_commit() and selinux_policy_retire()?
>
> I'm open to other ideas as well.
>
I think if you look at the 2nd patch, you'll see that this won't work 
because security_load_policy() is then changed to return newpolicy to 
the caller, and selinuxfs then calls selinux_commit_policy() after 
updating selinuxfs.  In order to provide the full exclusion guarantee, 
we need the mutex held across both security_load_policy() and 
selinux_commit_policy(). At that point we'd have to take the mutex 
lock/unlock up to selinuxfs and we already have fsi->mutex there.  This 
load_mutex was just to document the exclusion guarantee at the 
security/ss/services.c level and provide something we could pass to 
lockdep for safety checking when/if we convert to RCU.  If you really 
don't like it (and I'm not super excited about it myself), then I think 
I'll just put a comment in security_load_policy() explaining why we 
don't need to take policy read-lock there and drop load_mutex.  Thoughts?
Paul Moore Aug. 12, 2020, 1:50 a.m. UTC | #3 
On Fri, Aug 7, 2020 at 8:20 AM Stephen Smalley
<stephen.smalley.work@gmail.com> wrote:
> On 8/6/20 11:41 PM, Paul Moore wrote:
>
> > On Wed, Aug 5, 2020 at 11:52 AM Stephen Smalley
> > <stephen.smalley.work@gmail.com> wrote:
> >> Encapsulate the policy state in its own structure (struct
> >> selinux_policy) that is separately allocated but referenced from the
> >> selinux_ss structure.  The policy state includes the SID table
> >> (particularly the context structures), the policy database, and the
> >> mapping between the kernel classes/permissions and the policy values.
> >> Refactor the security server portion of the policy load logic to
> >> cleanly separate loading of the new structures from committing the new
> >> policy.  Unify the initial policy load and reload code paths as much
> >> as possible, avoiding duplicated code.  Make sure we are taking the
> >> policy read-lock prior to any dereferencing of the policy.  Move the
> >> copying of the policy capability booleans into the state structure
> >> outside of the policy write-lock because they are separate from the
> >> policy and are read outside of any policy lock; possibly they should
> >> be using at least READ_ONCE/WRITE_ONCE or smp_load_acquire/store_release.
> >> Restore the load mutex that was previously removed by
> >> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy")
> >> to make explicit the exclusion even though it is currently redundant
> >> with the fsi->mutex held by selinuxfs; this makes clear that we do
> >> not need to take the policy read-lock across sidtab_convert() and will
> >> be useful in the future for lockdep checking.
> >>
> >> These changes simplify the policy loading logic, reduce the size of
> >> the critical section while holding the policy write-lock, and should
> >> facilitate future changes to e.g. refactor the entire policy reload
> >> logic including the selinuxfs code to make the updating of the policy
> >> and the selinuxfs directory tree atomic and/or to convert the policy
> >> read-write lock to RCU.
> >>
> >> Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> >> ---
> >> v4 does not take the policy read-lock across sidtab_convert() and
> >> therefore does not require changing allocations by it to be atomic
> >> or dropping the cond_resched() call.  To make obvious that taking
> >> the policy read-lock is not necessary in security_load_policy(), restore
> >> the load mutex to security_load_policy() that was removed back in
> >> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy").
> >> However, since we have refactored security_load_policy() in this change
> >> to split out selinux_policy_commit(), we need to take the mutex in
> >> security_load_policy() and release it in selinux_policy_commit().
> > I'm not in love with the idea of splitting the lock/unlock across
> > different functions, more below in the relevant code section.
>
>
> Me either, but I see no alternative other than taking/releasing the
> mutex in selinuxfs, at which point it is truly no different than
> fsi->mutex.
>
> > I can somewhat understand if you don't want to have all the old policy
> > cleanup, reset, and notify code in security_load_policy(), but I
> > really dislike that the mutex lock/unlock is split across the two
> > functions.
> >
> > What if selinux_policy_commit() returned oldpolicy on success and we
> > created a new function, selinux_policy_retire() (name?), that would be
> > called from security_load_policy and could handle the cleanup, reset,
> > and notify code.  The mutex unlock could happen between the calls to
> > selinux_policy_commit() and selinux_policy_retire()?
> >
> > I'm open to other ideas as well.
> >
> I think if you look at the 2nd patch, you'll see that this won't work
> because security_load_policy() is then changed to return newpolicy to
> the caller, and selinuxfs then calls selinux_commit_policy() after
> updating selinuxfs.  In order to provide the full exclusion guarantee,
> we need the mutex held across both security_load_policy() and
> selinux_commit_policy(). At that point we'd have to take the mutex
> lock/unlock up to selinuxfs and we already have fsi->mutex there.  This
> load_mutex was just to document the exclusion guarantee at the
> security/ss/services.c level and provide something we could pass to
> lockdep for safety checking when/if we convert to RCU.  If you really
> don't like it (and I'm not super excited about it myself), then I think
> I'll just put a comment in security_load_policy() explaining why we
> don't need to take policy read-lock there and drop load_mutex.  Thoughts?

I think this is a case where the separation of the security server
from the Linux integration code is not doing us any favors.

While not taking a policy lock does seem a bit awkward here, I agree
that given the way the code is structured we are pretty much stuck
with doing the locking in the selinuxfs code ... which it appears is
what you've done in v5.  I'm dealing with limited network access at
the moment, and the merge window is still open, so I'll defer a proper
review of v5 until after the merge window closes but if the mutex
removal is the only significant change I don't suspect there will be
any significant comments.
Peter Enderborg Aug. 12, 2020, 7:15 a.m. UTC | #4 
On 8/7/20 5:41 AM, Paul Moore wrote:
> On Wed, Aug 5, 2020 at 11:52 AM Stephen Smalley
> <stephen.smalley.work@gmail.com> wrote:
>> Encapsulate the policy state in its own structure (struct
>> selinux_policy) that is separately allocated but referenced from the
>> selinux_ss structure.  The policy state includes the SID table
>> (particularly the context structures), the policy database, and the
>> mapping between the kernel classes/permissions and the policy values.
>> Refactor the security server portion of the policy load logic to
>> cleanly separate loading of the new structures from committing the new
>> policy.  Unify the initial policy load and reload code paths as much
>> as possible, avoiding duplicated code.  Make sure we are taking the
>> policy read-lock prior to any dereferencing of the policy.  Move the
>> copying of the policy capability booleans into the state structure
>> outside of the policy write-lock because they are separate from the
>> policy and are read outside of any policy lock; possibly they should
>> be using at least READ_ONCE/WRITE_ONCE or smp_load_acquire/store_release.
>> Restore the load mutex that was previously removed by
>> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy")
>> to make explicit the exclusion even though it is currently redundant
>> with the fsi->mutex held by selinuxfs; this makes clear that we do
>> not need to take the policy read-lock across sidtab_convert() and will
>> be useful in the future for lockdep checking.
>>
>> These changes simplify the policy loading logic, reduce the size of
>> the critical section while holding the policy write-lock, and should
>> facilitate future changes to e.g. refactor the entire policy reload
>> logic including the selinuxfs code to make the updating of the policy
>> and the selinuxfs directory tree atomic and/or to convert the policy
>> read-write lock to RCU.
>>
>> Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
>> ---
>> v4 does not take the policy read-lock across sidtab_convert() and
>> therefore does not require changing allocations by it to be atomic
>> or dropping the cond_resched() call.  To make obvious that taking
>> the policy read-lock is not necessary in security_load_policy(), restore
>> the load mutex to security_load_policy() that was removed back in
>> commit 89abd0acf033 ("SELinux: drop load_mutex in security_load_policy").
>> However, since we have refactored security_load_policy() in this change
>> to split out selinux_policy_commit(), we need to take the mutex in
>> security_load_policy() and release it in selinux_policy_commit().
> I'm not in love with the idea of splitting the lock/unlock across
> different functions, more below in the relevant code section.
>
>>  security/selinux/ss/services.c | 403 +++++++++++++++++----------------
>>  security/selinux/ss/services.h |  11 +-
>>  2 files changed, 220 insertions(+), 194 deletions(-)
> ...
>
>
>> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
>> index 9e76a80db6e1..6dea93fac9e2 100644
>> --- a/security/selinux/ss/services.c
>> +++ b/security/selinux/ss/services.c
>> @@ -2115,11 +2126,73 @@ static void security_load_policycaps(struct selinux_state *state)
>>                         pr_info("SELinux:  unknown policy capability %u\n",
>>                                 i);
>>         }
>> +
>> +       read_unlock(&state->ss->policy_rwlock);
>>  }
>>
>>  static int security_preserve_bools(struct selinux_state *state,
>>                                    struct policydb *newpolicydb);
>>
>> +static void selinux_policy_free(struct selinux_policy *policy)
>> +{
>> +       if (!policy)
>> +               return;
>> +
>> +       policydb_destroy(&policy->policydb);
>> +       sidtab_destroy(&policy->sidtab);
>> +       kfree(policy->map.mapping);
>> +       kfree(policy);
>> +}
>> +
>> +static void selinux_policy_commit(struct selinux_state *state,
>> +                               struct selinux_policy *newpolicy)
>> +{
>> +       struct selinux_policy *oldpolicy;
>> +       u32 seqno;
>> +
>> +       lockdep_assert_held(&state->ss->load_mutex);
>> +
>> +       /* If switching between different policy types, log MLS status */
>> +       oldpolicy = state->ss->policy;
>> +       if (oldpolicy) {
>> +               if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
>> +                       pr_info("SELinux: Disabling MLS support...\n");
>> +               else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
>> +                       pr_info("SELinux: Enabling MLS support...\n");
>> +       }
>> +
>> +       /* Install the new policy. */
>> +       write_lock_irq(&state->ss->policy_rwlock);
>> +       state->ss->policy = newpolicy;
>> +       seqno = ++state->ss->latest_granting;
>> +       write_unlock_irq(&state->ss->policy_rwlock);
>> +
>> +       /* Load the policycaps from the new policy */
>> +       security_load_policycaps(state);
>> +
>> +       if (!selinux_initialized(state)) {
>> +               /*
>> +                * After first policy load, the security server is
>> +                * marked as initialized and ready to handle requests and
>> +                * any objects created prior to policy load are then labeled.
>> +                */
>> +               selinux_mark_initialized(state);
>> +               mutex_unlock(&state->ss->load_mutex);
>> +               selinux_complete_init();
>> +       } else
>> +               mutex_unlock(&state->ss->load_mutex);
>> +
>> +       /* Free the old policy */
>> +       selinux_policy_free(oldpolicy);
>> +
>> +       /* Flush external caches and notify userspace of policy load */
>> +       avc_ss_reset(state->avc, seqno);
>> +       selnl_notify_policyload(seqno);
>> +       selinux_status_update_policyload(state, seqno);
>> +       selinux_netlbl_cache_invalidate();
>> +       selinux_xfrm_notify_policyload();
>> +}
> I can somewhat understand if you don't want to have all the old policy
> cleanup, reset, and notify code in security_load_policy(), but I
> really dislike that the mutex lock/unlock is split across the two
> functions.
>
> What if selinux_policy_commit() returned oldpolicy on success and we
> created a new function, selinux_policy_retire() (name?), that would be
> called from security_load_policy and could handle the cleanup, reset,
> and notify code.  The mutex unlock could happen between the calls to
> selinux_policy_commit() and selinux_policy_retire()?
>
> I'm open to other ideas as well.
>
Something similar to that will most likely be needed for a move to rcu lock anyway.
diff mbox series

Patch

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 9e76a80db6e1..6dea93fac9e2 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -81,6 +81,7 @@  static struct selinux_ss selinux_ss;
 void selinux_ss_init(struct selinux_ss **ss)
 {
 	rwlock_init(&selinux_ss.policy_rwlock);
+	mutex_init(&selinux_ss.load_mutex);
 	*ss = &selinux_ss;
 }
 
@@ -248,9 +249,15 @@  static void map_decision(struct selinux_map *map,
 
 int security_mls_enabled(struct selinux_state *state)
 {
-	struct policydb *p = &state->ss->policydb;
+	int mls_enabled;
 
-	return p->mls_enabled;
+	if (!selinux_initialized(state))
+		return 0;
+
+	read_lock(&state->ss->policy_rwlock);
+	mls_enabled = state->ss->policy->policydb.mls_enabled;
+	read_unlock(&state->ss->policy_rwlock);
+	return mls_enabled;
 }
 
 /*
@@ -726,8 +733,8 @@  static int security_validtrans_handle_fail(struct selinux_state *state,
 					   struct sidtab_entry *tentry,
 					   u16 tclass)
 {
-	struct policydb *p = &state->ss->policydb;
-	struct sidtab *sidtab = state->ss->sidtab;
+	struct policydb *p = &state->ss->policy->policydb;
+	struct sidtab *sidtab = &state->ss->policy->sidtab;
 	char *o = NULL, *n = NULL, *t = NULL;
 	u32 olen, nlen, tlen;
 
@@ -771,11 +778,11 @@  static int security_compute_validatetrans(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	if (!user)
-		tclass = unmap_class(&state->ss->map, orig_tclass);
+		tclass = unmap_class(&state->ss->policy->map, orig_tclass);
 	else
 		tclass = orig_tclass;
 
@@ -872,8 +879,8 @@  int security_bounded_transition(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	rc = -EINVAL;
 	old_entry = sidtab_search_entry(sidtab, old_sid);
@@ -1029,8 +1036,8 @@  void security_compute_xperms_decision(struct selinux_state *state,
 	if (!selinux_initialized(state))
 		goto allow;
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	scontext = sidtab_search(sidtab, ssid);
 	if (!scontext) {
@@ -1046,7 +1053,7 @@  void security_compute_xperms_decision(struct selinux_state *state,
 		goto out;
 	}
 
-	tclass = unmap_class(&state->ss->map, orig_tclass);
+	tclass = unmap_class(&state->ss->policy->map, orig_tclass);
 	if (unlikely(orig_tclass && !tclass)) {
 		if (policydb->allow_unknown)
 			goto allow;
@@ -1114,8 +1121,8 @@  void security_compute_av(struct selinux_state *state,
 	if (!selinux_initialized(state))
 		goto allow;
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	scontext = sidtab_search(sidtab, ssid);
 	if (!scontext) {
@@ -1135,7 +1142,7 @@  void security_compute_av(struct selinux_state *state,
 		goto out;
 	}
 
-	tclass = unmap_class(&state->ss->map, orig_tclass);
+	tclass = unmap_class(&state->ss->policy->map, orig_tclass);
 	if (unlikely(orig_tclass && !tclass)) {
 		if (policydb->allow_unknown)
 			goto allow;
@@ -1143,7 +1150,7 @@  void security_compute_av(struct selinux_state *state,
 	}
 	context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
 				  xperms);
-	map_decision(&state->ss->map, orig_tclass, avd,
+	map_decision(&state->ss->policy->map, orig_tclass, avd,
 		     policydb->allow_unknown);
 out:
 	read_unlock(&state->ss->policy_rwlock);
@@ -1168,8 +1175,8 @@  void security_compute_av_user(struct selinux_state *state,
 	if (!selinux_initialized(state))
 		goto allow;
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	scontext = sidtab_search(sidtab, ssid);
 	if (!scontext) {
@@ -1292,7 +1299,7 @@  int security_sidtab_hash_stats(struct selinux_state *state, char *page)
 	}
 
 	read_lock(&state->ss->policy_rwlock);
-	rc = sidtab_hash_stats(state->ss->sidtab, page);
+	rc = sidtab_hash_stats(&state->ss->policy->sidtab, page);
 	read_unlock(&state->ss->policy_rwlock);
 
 	return rc;
@@ -1340,8 +1347,8 @@  static int security_sid_to_context_core(struct selinux_state *state,
 		return -EINVAL;
 	}
 	read_lock(&state->ss->policy_rwlock);
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	if (force)
 		entry = sidtab_search_entry_force(sidtab, sid);
@@ -1534,8 +1541,8 @@  static int security_context_to_sid_core(struct selinux_state *state,
 			goto out;
 	}
 	read_lock(&state->ss->policy_rwlock);
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 	rc = string_to_context_struct(policydb, sidtab, scontext2,
 				      &context, def_sid);
 	if (rc == -EINVAL && force) {
@@ -1622,8 +1629,8 @@  static int compute_sid_handle_invalid_context(
 	u16 tclass,
 	struct context *newcontext)
 {
-	struct policydb *policydb = &state->ss->policydb;
-	struct sidtab *sidtab = state->ss->sidtab;
+	struct policydb *policydb = &state->ss->policy->policydb;
+	struct sidtab *sidtab = &state->ss->policy->sidtab;
 	char *s = NULL, *t = NULL, *n = NULL;
 	u32 slen, tlen, nlen;
 	struct audit_buffer *ab;
@@ -1719,16 +1726,16 @@  static int security_compute_sid(struct selinux_state *state,
 	read_lock(&state->ss->policy_rwlock);
 
 	if (kern) {
-		tclass = unmap_class(&state->ss->map, orig_tclass);
+		tclass = unmap_class(&state->ss->policy->map, orig_tclass);
 		sock = security_is_socket_class(orig_tclass);
 	} else {
 		tclass = orig_tclass;
-		sock = security_is_socket_class(map_class(&state->ss->map,
+		sock = security_is_socket_class(map_class(&state->ss->policy->map,
 							  tclass));
 	}
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	sentry = sidtab_search_entry(sidtab, ssid);
 	if (!sentry) {
@@ -1945,7 +1952,7 @@  static inline int convert_context_handle_invalid_context(
 	struct selinux_state *state,
 	struct context *context)
 {
-	struct policydb *policydb = &state->ss->policydb;
+	struct policydb *policydb = &state->ss->policy->policydb;
 	char *s;
 	u32 len;
 
@@ -2098,10 +2105,14 @@  static int convert_context(struct context *oldc, struct context *newc, void *p)
 
 static void security_load_policycaps(struct selinux_state *state)
 {
-	struct policydb *p = &state->ss->policydb;
+	struct policydb *p;
 	unsigned int i;
 	struct ebitmap_node *node;
 
+	read_lock(&state->ss->policy_rwlock);
+
+	p = &state->ss->policy->policydb;
+
 	for (i = 0; i < ARRAY_SIZE(state->policycap); i++)
 		state->policycap[i] = ebitmap_get_bit(&p->policycaps, i);
 
@@ -2115,11 +2126,73 @@  static void security_load_policycaps(struct selinux_state *state)
 			pr_info("SELinux:  unknown policy capability %u\n",
 				i);
 	}
+
+	read_unlock(&state->ss->policy_rwlock);
 }
 
 static int security_preserve_bools(struct selinux_state *state,
 				   struct policydb *newpolicydb);
 
+static void selinux_policy_free(struct selinux_policy *policy)
+{
+	if (!policy)
+		return;
+
+	policydb_destroy(&policy->policydb);
+	sidtab_destroy(&policy->sidtab);
+	kfree(policy->map.mapping);
+	kfree(policy);
+}
+
+static void selinux_policy_commit(struct selinux_state *state,
+				struct selinux_policy *newpolicy)
+{
+	struct selinux_policy *oldpolicy;
+	u32 seqno;
+
+	lockdep_assert_held(&state->ss->load_mutex);
+
+	/* If switching between different policy types, log MLS status */
+	oldpolicy = state->ss->policy;
+	if (oldpolicy) {
+		if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
+			pr_info("SELinux: Disabling MLS support...\n");
+		else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
+			pr_info("SELinux: Enabling MLS support...\n");
+	}
+
+	/* Install the new policy. */
+	write_lock_irq(&state->ss->policy_rwlock);
+	state->ss->policy = newpolicy;
+	seqno = ++state->ss->latest_granting;
+	write_unlock_irq(&state->ss->policy_rwlock);
+
+	/* Load the policycaps from the new policy */
+	security_load_policycaps(state);
+
+	if (!selinux_initialized(state)) {
+		/*
+		 * After first policy load, the security server is
+		 * marked as initialized and ready to handle requests and
+		 * any objects created prior to policy load are then labeled.
+		 */
+		selinux_mark_initialized(state);
+		mutex_unlock(&state->ss->load_mutex);
+		selinux_complete_init();
+	} else
+		mutex_unlock(&state->ss->load_mutex);
+
+	/* Free the old policy */
+	selinux_policy_free(oldpolicy);
+
+	/* Flush external caches and notify userspace of policy load */
+	avc_ss_reset(state->avc, seqno);
+	selnl_notify_policyload(seqno);
+	selinux_status_update_policyload(state, seqno);
+	selinux_netlbl_cache_invalidate();
+	selinux_xfrm_notify_policyload();
+}
+
 /**
  * security_load_policy - Load a security policy configuration.
  * @data: binary policy data
@@ -2132,166 +2205,82 @@  static int security_preserve_bools(struct selinux_state *state,
  */
 int security_load_policy(struct selinux_state *state, void *data, size_t len)
 {
-	struct policydb *policydb;
-	struct sidtab *oldsidtab, *newsidtab;
-	struct policydb *oldpolicydb, *newpolicydb;
-	struct selinux_mapping *oldmapping;
-	struct selinux_map newmap;
+	struct selinux_policy *newpolicy;
 	struct sidtab_convert_params convert_params;
 	struct convert_context_args args;
-	u32 seqno;
 	int rc = 0;
 	struct policy_file file = { data, len }, *fp = &file;
 
-	policydb = &state->ss->policydb;
-
-	newsidtab = kmalloc(sizeof(*newsidtab), GFP_KERNEL);
-	if (!newsidtab)
+	newpolicy = kzalloc(sizeof(*newpolicy), GFP_KERNEL);
+	if (!newpolicy)
 		return -ENOMEM;
 
-	if (!selinux_initialized(state)) {
-		rc = policydb_read(policydb, fp);
-		if (rc) {
-			kfree(newsidtab);
-			return rc;
-		}
-
-		policydb->len = len;
-		rc = selinux_set_mapping(policydb, secclass_map,
-					 &state->ss->map);
-		if (rc) {
-			kfree(newsidtab);
-			policydb_destroy(policydb);
-			return rc;
-		}
-
-		rc = policydb_load_isids(policydb, newsidtab);
-		if (rc) {
-			kfree(newsidtab);
-			policydb_destroy(policydb);
-			return rc;
-		}
-
-		state->ss->sidtab = newsidtab;
-		security_load_policycaps(state);
-		selinux_mark_initialized(state);
-		seqno = ++state->ss->latest_granting;
-		selinux_complete_init();
-		avc_ss_reset(state->avc, seqno);
-		selnl_notify_policyload(seqno);
-		selinux_status_update_policyload(state, seqno);
-		selinux_netlbl_cache_invalidate();
-		selinux_xfrm_notify_policyload();
-		return 0;
-	}
+	rc = policydb_read(&newpolicy->policydb, fp);
+	if (rc)
+		goto err;
 
-	oldpolicydb = kcalloc(2, sizeof(*oldpolicydb), GFP_KERNEL);
-	if (!oldpolicydb) {
-		kfree(newsidtab);
-		return -ENOMEM;
-	}
-	newpolicydb = oldpolicydb + 1;
+	newpolicy->policydb.len = len;
+	rc = selinux_set_mapping(&newpolicy->policydb, secclass_map,
+				&newpolicy->map);
+	if (rc)
+		goto err;
 
-	rc = policydb_read(newpolicydb, fp);
+	rc = policydb_load_isids(&newpolicy->policydb, &newpolicy->sidtab);
 	if (rc) {
-		kfree(newsidtab);
-		goto out;
+		pr_err("SELinux:  unable to load the initial SIDs\n");
+		goto err;
 	}
 
-	newpolicydb->len = len;
-	/* If switching between different policy types, log MLS status */
-	if (policydb->mls_enabled && !newpolicydb->mls_enabled)
-		pr_info("SELinux: Disabling MLS support...\n");
-	else if (!policydb->mls_enabled && newpolicydb->mls_enabled)
-		pr_info("SELinux: Enabling MLS support...\n");
+	mutex_lock(&state->ss->load_mutex);
 
-	rc = policydb_load_isids(newpolicydb, newsidtab);
-	if (rc) {
-		pr_err("SELinux:  unable to load the initial SIDs\n");
-		policydb_destroy(newpolicydb);
-		kfree(newsidtab);
-		goto out;
+	if (!selinux_initialized(state)) {
+		/* First policy load, so no need to preserve state from old policy */
+		selinux_policy_commit(state, newpolicy);
+		return 0;
 	}
 
-	rc = selinux_set_mapping(newpolicydb, secclass_map, &newmap);
-	if (rc)
-		goto err;
-
-	rc = security_preserve_bools(state, newpolicydb);
+	/* Preserve active boolean values from the old policy */
+	rc = security_preserve_bools(state, &newpolicy->policydb);
 	if (rc) {
 		pr_err("SELinux:  unable to preserve booleans\n");
-		goto err;
+		goto err_unlock;
 	}
 
-	oldsidtab = state->ss->sidtab;
-
 	/*
 	 * Convert the internal representations of contexts
 	 * in the new SID table.
 	 */
 	args.state = state;
-	args.oldp = policydb;
-	args.newp = newpolicydb;
+	args.oldp = &state->ss->policy->policydb;
+	args.newp = &newpolicy->policydb;
 
 	convert_params.func = convert_context;
 	convert_params.args = &args;
-	convert_params.target = newsidtab;
+	convert_params.target = &newpolicy->sidtab;
 
-	rc = sidtab_convert(oldsidtab, &convert_params);
+	rc = sidtab_convert(&state->ss->policy->sidtab, &convert_params);
 	if (rc) {
 		pr_err("SELinux:  unable to convert the internal"
 			" representation of contexts in the new SID"
 			" table\n");
-		goto err;
+		goto err_unlock;
 	}
 
-	/* Save the old policydb and SID table to free later. */
-	memcpy(oldpolicydb, policydb, sizeof(*policydb));
-
-	/* Install the new policydb and SID table. */
-	write_lock_irq(&state->ss->policy_rwlock);
-	memcpy(policydb, newpolicydb, sizeof(*policydb));
-	state->ss->sidtab = newsidtab;
-	security_load_policycaps(state);
-	oldmapping = state->ss->map.mapping;
-	state->ss->map.mapping = newmap.mapping;
-	state->ss->map.size = newmap.size;
-	seqno = ++state->ss->latest_granting;
-	write_unlock_irq(&state->ss->policy_rwlock);
-
-	/* Free the old policydb and SID table. */
-	policydb_destroy(oldpolicydb);
-	sidtab_destroy(oldsidtab);
-	kfree(oldsidtab);
-	kfree(oldmapping);
-
-	avc_ss_reset(state->avc, seqno);
-	selnl_notify_policyload(seqno);
-	selinux_status_update_policyload(state, seqno);
-	selinux_netlbl_cache_invalidate();
-	selinux_xfrm_notify_policyload();
-
-	rc = 0;
-	goto out;
-
+	selinux_policy_commit(state, newpolicy);
+	return 0;
+err_unlock:
+	mutex_unlock(&state->ss->load_mutex);
 err:
-	kfree(newmap.mapping);
-	sidtab_destroy(newsidtab);
-	kfree(newsidtab);
-	policydb_destroy(newpolicydb);
-
-out:
-	kfree(oldpolicydb);
+	selinux_policy_free(newpolicy);
 	return rc;
 }
 
 size_t security_policydb_len(struct selinux_state *state)
 {
-	struct policydb *p = &state->ss->policydb;
 	size_t len;
 
 	read_lock(&state->ss->policy_rwlock);
-	len = p->len;
+	len = state->ss->policy->policydb.len;
 	read_unlock(&state->ss->policy_rwlock);
 
 	return len;
@@ -2313,8 +2302,8 @@  int security_port_sid(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	c = policydb->ocontexts[OCON_PORT];
 	while (c) {
@@ -2358,8 +2347,8 @@  int security_ib_pkey_sid(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	c = policydb->ocontexts[OCON_IBPKEY];
 	while (c) {
@@ -2404,8 +2393,8 @@  int security_ib_endport_sid(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	c = policydb->ocontexts[OCON_IBENDPORT];
 	while (c) {
@@ -2449,8 +2438,8 @@  int security_netif_sid(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	c = policydb->ocontexts[OCON_NETIF];
 	while (c) {
@@ -2512,8 +2501,8 @@  int security_node_sid(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	switch (domain) {
 	case AF_INET: {
@@ -2612,8 +2601,8 @@  int security_get_user_sids(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	context_init(&usercon);
 
@@ -2714,8 +2703,8 @@  static inline int __security_genfs_sid(struct selinux_state *state,
 				       u16 orig_sclass,
 				       u32 *sid)
 {
-	struct policydb *policydb = &state->ss->policydb;
-	struct sidtab *sidtab = state->ss->sidtab;
+	struct policydb *policydb = &state->ss->policy->policydb;
+	struct sidtab *sidtab = &state->ss->policy->sidtab;
 	int len;
 	u16 sclass;
 	struct genfs *genfs;
@@ -2725,7 +2714,7 @@  static inline int __security_genfs_sid(struct selinux_state *state,
 	while (path[0] == '/' && path[1] == '/')
 		path++;
 
-	sclass = unmap_class(&state->ss->map, orig_sclass);
+	sclass = unmap_class(&state->ss->policy->map, orig_sclass);
 	*sid = SECINITSID_UNLABELED;
 
 	for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
@@ -2800,8 +2789,8 @@  int security_fs_use(struct selinux_state *state, struct super_block *sb)
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
-	sidtab = state->ss->sidtab;
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
 
 	c = policydb->ocontexts[OCON_FSUSE];
 	while (c) {
@@ -2851,7 +2840,7 @@  int security_get_bools(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
+	policydb = &state->ss->policy->policydb;
 
 	*names = NULL;
 	*values = NULL;
@@ -2902,7 +2891,7 @@  int security_set_bools(struct selinux_state *state, u32 len, int *values)
 
 	write_lock_irq(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
+	policydb = &state->ss->policy->policydb;
 
 	rc = -EFAULT;
 	lenp = policydb->p_bools.nprim;
@@ -2950,7 +2939,7 @@  int security_get_bool_value(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
-	policydb = &state->ss->policydb;
+	policydb = &state->ss->policy->policydb;
 
 	rc = -EFAULT;
 	len = policydb->p_bools.nprim;
@@ -2998,8 +2987,8 @@  static int security_preserve_bools(struct selinux_state *state,
 int security_sid_mls_copy(struct selinux_state *state,
 			  u32 sid, u32 mls_sid, u32 *new_sid)
 {
-	struct policydb *policydb = &state->ss->policydb;
-	struct sidtab *sidtab = state->ss->sidtab;
+	struct policydb *policydb;
+	struct sidtab *sidtab;
 	struct context *context1;
 	struct context *context2;
 	struct context newcon;
@@ -3008,7 +2997,7 @@  int security_sid_mls_copy(struct selinux_state *state,
 	int rc;
 
 	rc = 0;
-	if (!selinux_initialized(state) || !policydb->mls_enabled) {
+	if (!selinux_initialized(state)) {
 		*new_sid = sid;
 		goto out;
 	}
@@ -3017,6 +3006,14 @@  int security_sid_mls_copy(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
+
+	if (!policydb->mls_enabled) {
+		*new_sid = sid;
+		goto out_unlock;
+	}
+
 	rc = -EINVAL;
 	context1 = sidtab_search(sidtab, sid);
 	if (!context1) {
@@ -3094,8 +3091,8 @@  int security_net_peersid_resolve(struct selinux_state *state,
 				 u32 xfrm_sid,
 				 u32 *peer_sid)
 {
-	struct policydb *policydb = &state->ss->policydb;
-	struct sidtab *sidtab = state->ss->sidtab;
+	struct policydb *policydb;
+	struct sidtab *sidtab;
 	int rc;
 	struct context *nlbl_ctx;
 	struct context *xfrm_ctx;
@@ -3117,15 +3114,20 @@  int security_net_peersid_resolve(struct selinux_state *state,
 		return 0;
 	}
 
+	read_lock(&state->ss->policy_rwlock);
+
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
+
 	/*
 	 * We don't need to check initialized here since the only way both
 	 * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
 	 * security server was initialized and state->initialized was true.
 	 */
-	if (!policydb->mls_enabled)
-		return 0;
-
-	read_lock(&state->ss->policy_rwlock);
+	if (!policydb->mls_enabled) {
+		rc = 0;
+		goto out;
+	}
 
 	rc = -EINVAL;
 	nlbl_ctx = sidtab_search(sidtab, nlbl_sid);
@@ -3172,7 +3174,7 @@  static int get_classes_callback(void *k, void *d, void *args)
 int security_get_classes(struct selinux_state *state,
 			 char ***classes, int *nclasses)
 {
-	struct policydb *policydb = &state->ss->policydb;
+	struct policydb *policydb;
 	int rc;
 
 	if (!selinux_initialized(state)) {
@@ -3183,6 +3185,8 @@  int security_get_classes(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
+	policydb = &state->ss->policy->policydb;
+
 	rc = -ENOMEM;
 	*nclasses = policydb->p_classes.nprim;
 	*classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
@@ -3219,12 +3223,14 @@  static int get_permissions_callback(void *k, void *d, void *args)
 int security_get_permissions(struct selinux_state *state,
 			     char *class, char ***perms, int *nperms)
 {
-	struct policydb *policydb = &state->ss->policydb;
+	struct policydb *policydb;
 	int rc, i;
 	struct class_datum *match;
 
 	read_lock(&state->ss->policy_rwlock);
 
+	policydb = &state->ss->policy->policydb;
+
 	rc = -EINVAL;
 	match = symtab_search(&policydb->p_classes, class);
 	if (!match) {
@@ -3265,12 +3271,22 @@  int security_get_permissions(struct selinux_state *state,
 
 int security_get_reject_unknown(struct selinux_state *state)
 {
-	return state->ss->policydb.reject_unknown;
+	int value;
+
+	read_lock(&state->ss->policy_rwlock);
+	value = state->ss->policy->policydb.reject_unknown;
+	read_unlock(&state->ss->policy_rwlock);
+	return value;
 }
 
 int security_get_allow_unknown(struct selinux_state *state)
 {
-	return state->ss->policydb.allow_unknown;
+	int value;
+
+	read_lock(&state->ss->policy_rwlock);
+	value = state->ss->policy->policydb.allow_unknown;
+	read_unlock(&state->ss->policy_rwlock);
+	return value;
 }
 
 /**
@@ -3286,11 +3302,10 @@  int security_get_allow_unknown(struct selinux_state *state)
 int security_policycap_supported(struct selinux_state *state,
 				 unsigned int req_cap)
 {
-	struct policydb *policydb = &state->ss->policydb;
 	int rc;
 
 	read_lock(&state->ss->policy_rwlock);
-	rc = ebitmap_get_bit(&policydb->policycaps, req_cap);
+	rc = ebitmap_get_bit(&state->ss->policy->policydb.policycaps, req_cap);
 	read_unlock(&state->ss->policy_rwlock);
 
 	return rc;
@@ -3314,7 +3329,7 @@  void selinux_audit_rule_free(void *vrule)
 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
 {
 	struct selinux_state *state = &selinux_state;
-	struct policydb *policydb = &state->ss->policydb;
+	struct policydb *policydb;
 	struct selinux_audit_rule *tmprule;
 	struct role_datum *roledatum;
 	struct type_datum *typedatum;
@@ -3359,6 +3374,8 @@  int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
 
 	read_lock(&state->ss->policy_rwlock);
 
+	policydb = &state->ss->policy->policydb;
+
 	tmprule->au_seqno = state->ss->latest_granting;
 
 	switch (field) {
@@ -3455,7 +3472,7 @@  int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
 		goto out;
 	}
 
-	ctxt = sidtab_search(state->ss->sidtab, sid);
+	ctxt = sidtab_search(&state->ss->policy->sidtab, sid);
 	if (unlikely(!ctxt)) {
 		WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
 			  sid);
@@ -3617,8 +3634,8 @@  int security_netlbl_secattr_to_sid(struct selinux_state *state,
 				   struct netlbl_lsm_secattr *secattr,
 				   u32 *sid)
 {
-	struct policydb *policydb = &state->ss->policydb;
-	struct sidtab *sidtab = state->ss->sidtab;
+	struct policydb *policydb;
+	struct sidtab *sidtab;
 	int rc;
 	struct context *ctx;
 	struct context ctx_new;
@@ -3630,6 +3647,9 @@  int security_netlbl_secattr_to_sid(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
+	policydb = &state->ss->policy->policydb;
+	sidtab = &state->ss->policy->sidtab;
+
 	if (secattr->flags & NETLBL_SECATTR_CACHE)
 		*sid = *(u32 *)secattr->cache->data;
 	else if (secattr->flags & NETLBL_SECATTR_SECID)
@@ -3686,7 +3706,7 @@  int security_netlbl_secattr_to_sid(struct selinux_state *state,
 int security_netlbl_sid_to_secattr(struct selinux_state *state,
 				   u32 sid, struct netlbl_lsm_secattr *secattr)
 {
-	struct policydb *policydb = &state->ss->policydb;
+	struct policydb *policydb;
 	int rc;
 	struct context *ctx;
 
@@ -3695,8 +3715,10 @@  int security_netlbl_sid_to_secattr(struct selinux_state *state,
 
 	read_lock(&state->ss->policy_rwlock);
 
+	policydb = &state->ss->policy->policydb;
+
 	rc = -ENOENT;
-	ctx = sidtab_search(state->ss->sidtab, sid);
+	ctx = sidtab_search(&state->ss->policy->sidtab, sid);
 	if (ctx == NULL)
 		goto out;
 
@@ -3725,7 +3747,6 @@  int security_netlbl_sid_to_secattr(struct selinux_state *state,
 int security_read_policy(struct selinux_state *state,
 			 void **data, size_t *len)
 {
-	struct policydb *policydb = &state->ss->policydb;
 	int rc;
 	struct policy_file fp;
 
@@ -3742,7 +3763,7 @@  int security_read_policy(struct selinux_state *state,
 	fp.len = *len;
 
 	read_lock(&state->ss->policy_rwlock);
-	rc = policydb_write(policydb, &fp);
+	rc = policydb_write(&state->ss->policy->policydb, &fp);
 	read_unlock(&state->ss->policy_rwlock);
 
 	if (rc)
diff --git a/security/selinux/ss/services.h b/security/selinux/ss/services.h
index a06f3d835216..da673fa38900 100644
--- a/security/selinux/ss/services.h
+++ b/security/selinux/ss/services.h
@@ -22,12 +22,17 @@  struct selinux_map {
 	u16 size; /* array size of mapping */
 };
 
-struct selinux_ss {
-	struct sidtab *sidtab;
+struct selinux_policy {
+	struct sidtab sidtab;
 	struct policydb policydb;
+	struct selinux_map map;
+};
+
+struct selinux_ss {
 	rwlock_t policy_rwlock;
+	struct mutex load_mutex;
 	u32 latest_granting;
-	struct selinux_map map;
+	struct selinux_policy *policy;
 } __randomize_layout;
 
 void services_compute_xperms_drivers(struct extended_perms *xperms,