diff --git a/keystore2/src/lib.rs b/keystore2/src/lib.rs
index dfdd228..b37773a 100644
--- a/keystore2/src/lib.rs
+++ b/keystore2/src/lib.rs
@@ -16,3 +16,4 @@
 
 pub mod database;
 pub mod error;
+pub mod permission;
diff --git a/keystore2/src/permission.rs b/keystore2/src/permission.rs
new file mode 100644
index 0000000..a5a63ee
--- /dev/null
+++ b/keystore2/src/permission.rs
@@ -0,0 +1,923 @@
+// Copyright 2020, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! This crate provides access control primitives for Keystore 2.0.
+//! It provides high level functions for checking permissions in the keystore2 and keystore2_key
+//! SELinux classes based on the keystore2_selinux backend.
+//! It also provides KeystorePerm and KeyPerm as convenience wrappers for the SELinux permission
+//! defined by keystore2 and keystore2_key respectively.
+
+use keystore_aidl_generated as aidl;
+
+use std::cmp::PartialEq;
+use std::convert::From;
+
+use crate::error::Error as KsError;
+use keystore2_selinux as selinux;
+
+use anyhow::Context as AnyhowContext;
+
+use selinux::Backend;
+
+// Replace getcon with a mock in the test situation
+#[cfg(not(test))]
+use selinux::getcon;
+#[cfg(test)]
+use tests::test_getcon as getcon;
+
+/// The below example wraps the enum MyPermission in the tuple struct `MyPerm` and implements
+///  * `From<i32> for `MyPerm`, where each unknown numeric value is mapped to the given default,
+///    here `None`
+///  * `Into<MyPermission> for `MyPerm`
+///  * `MyPerm::foo()` and `MyPerm::bar()` which construct MyPerm instances representing
+///    `MyPermission::Foo` and `MyPermission::Bar` respectively.
+///  * `MyPerm.to_selinux(&self)`, which returns the selinux string representation of the
+///    represented permission.
+///  * Tests in the given test namespace for each permision that check that the numeric
+///    representations of MyPermission and MyPerm match. (TODO replace with static assert if
+///    they become available.)
+///
+/// ## Special behavior
+/// If the keyword `use` appears as an selinux name `use_` is used as identifier for the
+/// constructor function (e.g. `MePerm::use_()`) but the string returned by `to_selinux` will
+/// still be `"use"`.
+///
+/// ## Example
+/// ```
+/// #[i32]
+/// enum MyPermission {
+///     None = 0,
+///     Foo = 1,
+///     Bar = 2,
+/// }
+///
+/// implement_permission!(
+///     /// MyPerm documentation.
+///     #[derive(Clone, Copy, Debug, PartialEq)]
+///     MyPermission as MyPerm with default (None = 0, none)
+///     and test namespace my_perm_tests {
+///         Foo = 1,           selinux name: foo;
+///         Bar = 2,           selinux name: bar;
+///     }
+/// );
+/// ```
+macro_rules! implement_permission {
+    // This rule provides the public interface of the macro. And starts the preprocessing
+    // recursion (see below).
+    ($(#[$m:meta])* $t:ty as $name:ident with default ($($def:tt)*)
+        and test namespace $tn:ident { $($element:tt)* })
+    => {
+        implement_permission!(@replace_use $($m)*, $t, $name, $tn, ($($def)*), [] , $($element)*);
+    };
+
+
+    // The following three rules recurse through the elements of the form
+    // `<enum variant> = <integer_literal>, selinux name: <selinux_name>;`
+    // preprocessing the input.
+
+    // The first rule terminates the recursion and passes the processed arguments to the final
+    // rule that spills out the implementation.
+    (@replace_use $($m:meta)*, $t:ty, $name:ident, $tn:ident, ($($def:tt)*), [$($out:tt)*], ) => {
+        implement_permission!(@end $($m)*, $t, $name, $tn, ($($def)*) { $($out)* } );
+    };
+
+    // The second rule is triggered if the selinux name of an element is literally `use`.
+    // It produces the tuple `<enum variant> = <integer_literal>, use_, use;`
+    // and appends it to the out list.
+    (@replace_use $($m:meta)*, $t:ty, $name:ident, $tn:ident, ($($def:tt)*), [$($out:tt)*],
+        $e_name:ident = $e_val:expr, selinux name: use; $($element:tt)*)
+    => {
+        implement_permission!(@replace_use $($m)*, $t, $name, $tn, ($($def)*),
+                              [$($out)* $e_name = $e_val, use_, use;], $($element)*);
+    };
+
+    // The third rule is the default rule which replaces every input tuple with
+    // `<enum variant> = <integer_literal>, <selinux_name>, <selinux_name>;`
+    // and appends the result to the out list.
+    (@replace_use $($m:meta)*, $t:ty, $name:ident, $tn:ident, ($($def:tt)*), [$($out:tt)*],
+        $e_name:ident = $e_val:expr, selinux name: $e_str:ident; $($element:tt)*)
+    => {
+        implement_permission!(@replace_use $($m)*, $t, $name, $tn, ($($def)*),
+                              [$($out)* $e_name = $e_val, $e_str, $e_str;], $($element)*);
+    };
+
+    (@end $($m:meta)*, $t:ty, $name:ident, $tn:ident,
+        ($def_name:ident = $def:expr, $def_selinux_name:ident) {
+            $($element_name:ident = $element_val:expr, $element_identifier:ident,
+                $selinux_name:ident;)*
+        })
+    =>
+    {
+        $(#[$m])*
+        pub struct $name($t);
+
+        impl From<i32> for $name {
+            fn from (p: i32) -> Self {
+                match p {
+                    $def => Self(<$t>::$def_name),
+                    $($element_val => Self(<$t>::$element_name),)*
+                    _ => Self(<$t>::$def_name),
+                }
+            }
+        }
+
+        impl Into<$t> for $name {
+            fn into(self) -> $t {
+                self.0
+            }
+        }
+
+        impl $name {
+            /// Returns a string representation of the permission as required by
+            /// `selinux::check_access`.
+            pub fn to_selinux(&self) -> &'static str {
+                match self {
+                    Self(<$t>::$def_name) => stringify!($def_selinux_name),
+                    $(Self(<$t>::$element_name) => stringify!($selinux_name),)*
+                }
+            }
+
+            /// Creates an instance representing a permission with the same name.
+            pub const fn $def_selinux_name() -> Self { Self(<$t>::$def_name) }
+            $(
+                /// Creates an instance representing a permission with the same name.
+                pub const fn $element_identifier() -> Self { Self(<$t>::$element_name) }
+             )*
+        }
+        #[cfg(test)]
+        mod $tn {
+            use super::*;
+
+            #[test]
+            fn $def_selinux_name() {
+                assert_eq!($name::$def_selinux_name(), (<$t>::$def_name as i32).into());
+            }
+            $(
+                #[test]
+                fn $element_identifier() {
+                    assert_eq!($name::$element_identifier(), (<$t>::$element_name as i32).into());
+                }
+            )*
+        }
+    };
+
+
+}
+
+implement_permission!(
+    /// KeyPerm provides a convenient abstraction from the SELinux class `keystore2_key`.
+    /// At the same time it maps `KeyPermissions` from the Keystore 2.0 AIDL Grant interface to
+    /// the SELinux permissions. With the implement_permission macro, we conveniently
+    /// provide mappings between the wire type bit field values, the rust enum and the SELinux
+    /// string representation.
+    ///
+    /// ## Example
+    ///
+    /// In this access check `KeyPerm::get_info().to_selinux()` would return the SELinux representation
+    /// "info".
+    /// ```
+    /// selinux::check_access(source_context, target_context, "keystore2_key",
+    ///                       KeyPerm::get_info().to_selinux());
+    /// ```
+    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+    aidl::KeyPermission as KeyPerm with default (None = 0, none)
+    and test namespace key_perm_tests {
+        Delete = 1,         selinux name: delete;
+        GenUniqueId = 2,    selinux name: gen_unique_id;
+        GetInfo = 4,        selinux name: get_info;
+        Grant = 8,          selinux name: grant;
+        List = 0x10,        selinux name: list;
+        ManageBlob = 0x20,  selinux name: manage_blob;
+        Rebind = 0x40,      selinux name: rebind;
+        ReqForcedOp = 0x80, selinux name: req_forced_op;
+        Update = 0x100,     selinux name: update;
+        Use = 0x200,        selinux name: use;
+        UseDevId = 0x400,   selinux name: use_dev_id;
+    }
+);
+
+/// KeystorePermission defines values for the SELinux `keystore2` security class.
+/// Countrary to `KeyPermission`, this enum is not generated by AIDL and need not be
+/// wrapped by newtype pattern. But we conveniently use the implement_permission macro
+/// to provide the same feature that we did for `KeyPermission` to this set of permissions.
+#[repr(i32)]
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum KeystorePermission {
+    /// `None` is not a permission that can ever be granted. It is not known to the SEPolicy.
+    None = 0,
+    /// Checked when a new auth token is installed.
+    AddAuth = 1,
+    /// Checked when an app is uninstalled or wiped.
+    ClearNs = 2,
+    /// Checked when the locked state of Keystore 2.0 is queried.
+    GetState = 4,
+    /// Checked when Keystore 2.0 gets locked.
+    Lock = 8,
+    /// Checked when Keystore 2.0 shall be reset.
+    Reset = 0x10,
+    /// Checked when Keystore 2.0 shall be unlocked.
+    Unlock = 0x20,
+}
+
+implement_permission!(
+    /// KeystorePerm provides a convenient abstraction from the SELinux class `keystore2`.
+    /// Using the implement_permission macro we get the same features as `KeyPerm`.
+    #[derive(Clone, Copy, Debug, PartialEq)]
+    KeystorePermission as KeystorePerm with default (None = 0, none)
+    and test namespace keystore_perm_tests {
+        AddAuth = 1,    selinux name: add_auth;
+        ClearNs = 2,    selinux name: clear_ns;
+        GetState = 4,   selinux name: get_state;
+        Lock = 8,       selinux name: lock;
+        Reset = 0x10,   selinux name: reset;
+        Unlock = 0x20,  selinux name: unlock;
+    }
+);
+
+/// Represents a set of `KeyPerm` permissions.
+/// `IntoIterator` is implemented for this struct allowing the iteration through all the
+/// permissions in the set.
+/// It also implements a function `includes(self, other)` that checks if the permissions
+/// in `other` are included in `self`.
+///
+/// KeyPermSet can be created with the macro `key_perm_set![]`.
+///
+/// ## Example
+/// ```
+/// let perms1 = key_perm_set![KeyPerm::use_(), KeyPerm::manage_blob(), KeyPerm::grant()];
+/// let perms2 = key_perm_set![KeyPerm::use_(), KeyPerm::manage_blob()];
+///
+/// assert!(perms1.includes(perms2))
+/// assert!(!perms2.includes(perms1))
+///
+/// let i = perms1.into_iter();
+/// // iteration in ascending order of the permission's numeric representation.
+/// assert_eq(Some(KeyPerm::manage_blob()), i.next());
+/// assert_eq(Some(KeyPerm::grant()), i.next());
+/// assert_eq(Some(KeyPerm::use_()), i.next());
+/// assert_eq(None, i.next());
+/// ```
+#[derive(Copy, Clone)]
+pub struct KeyPermSet(i32);
+
+mod perm {
+    use super::*;
+
+    pub struct IntoIter {
+        vec: KeyPermSet,
+        pos: u8,
+    }
+
+    impl IntoIter {
+        pub fn new(v: KeyPermSet) -> Self {
+            Self { vec: v, pos: 0 }
+        }
+    }
+
+    impl std::iter::Iterator for IntoIter {
+        type Item = KeyPerm;
+
+        fn next(&mut self) -> Option<Self::Item> {
+            loop {
+                if self.pos == 32 {
+                    return None;
+                }
+                let p = self.vec.0 & (1 << self.pos);
+                self.pos += 1;
+                if p != 0 {
+                    return Some(KeyPerm::from(p));
+                }
+            }
+        }
+    }
+}
+
+impl From<KeyPerm> for KeyPermSet {
+    fn from(p: KeyPerm) -> Self {
+        Self(p.0 as i32)
+    }
+}
+
+impl KeyPermSet {
+    /// Returns true iff this permission set has all of the permissions that are in `other`.
+    fn includes<T: Into<KeyPermSet>>(&self, other: T) -> bool {
+        let o: KeyPermSet = other.into();
+        (self.0 & o.0) == o.0
+    }
+}
+
+/// This macro can be used to create a `KeyPermSet` from a list of `KeyPerm` values.
+///
+/// ## Example
+/// ```
+/// let v = key_perm_set![Perm::delete(), Perm::manage_blob()];
+/// ```
+#[macro_export]
+macro_rules! key_perm_set {
+    () => { KeyPermSet(0) };
+    ($head:expr $(, $tail:expr)* $(,)?) => {
+        KeyPermSet($head.0 as i32 $(| $tail.0 as i32)*)
+    };
+}
+
+impl IntoIterator for KeyPermSet {
+    type Item = KeyPerm;
+    type IntoIter = perm::IntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        Self::IntoIter::new(self)
+    }
+}
+
+/// Uses `selinux::check_access` to check if the given caller context `caller_cxt` may access
+/// the given permision `perm` of the `keystore2` security class.
+pub fn check_keystore_permission(
+    caller_ctx: &selinux::Context,
+    perm: KeystorePerm,
+) -> anyhow::Result<()> {
+    let target_context = getcon().context("check_keystore_permission: getcon failed.")?;
+    selinux::check_access(caller_ctx, &target_context, "keystore2", perm.to_selinux())
+}
+
+/// Uses `selinux::check_access` to check if the given caller context `caller_cxt` has
+/// all the permissions indicated in `access_vec` for the target domain indicated by the key
+/// descriptor `key` in the security class `keystore2_key`.
+///
+/// Also checks if the caller has the grant permission for the given target domain.
+///
+/// Attempts to grant the grant permission are always denied.
+///
+/// The only viable target domains are
+///  * `Domain::App` in which case u:r:keystore:s0 is used as target context and
+///  * `Domain::SELinux` in which case the `key.namespace_` parameter is looked up in
+///                      SELinux keystore key backend, and the result is used
+///                      as target context.
+pub fn check_grant_permission(
+    caller_ctx: &selinux::Context,
+    access_vec: KeyPermSet,
+    key: &aidl::KeyDescriptor,
+) -> anyhow::Result<()> {
+    use aidl::Domain;
+    use selinux::KeystoreKeyBackend;
+
+    let target_context = match key.domain {
+        Domain::App => getcon().context("check_grant_permission: getcon failed.")?,
+        Domain::SELinux => {
+            // TODO cache an open backend, possible use a lazy static.
+            let backend = KeystoreKeyBackend::new().context(concat!(
+                "check_grant_permission: Domain::SELinux: ",
+                "Failed to create selinux keystore backend."
+            ))?;
+            backend
+                .lookup(format!("{}", key.namespace_).as_str())
+                .context("check_grant_permission: Domain::SELinux: Failed to lookup namespace")?
+        }
+        _ => return Err(KsError::sys()).context(format!("Cannot grant {:?}.", key.domain)),
+    };
+
+    selinux::check_access(caller_ctx, &target_context, "keystore2_key", "grant")
+        .context("Grant permission is required when granting.")?;
+
+    if access_vec.includes(KeyPerm::grant()) {
+        return Err(selinux::Error::perm()).context("Grant permission cannot be granted.");
+    }
+
+    for p in access_vec.into_iter() {
+        selinux::check_access(caller_ctx, &target_context, "keystore2_key", p.to_selinux())
+            .context(concat!(
+                "check_grant_permission: check_access failed. ",
+                "The caller may have tried to grant a permission that they don't possess."
+            ))?
+    }
+    Ok(())
+}
+
+/// Uses `selinux::check_access` to check if the given caller context `caller_cxt`
+/// has the permissions indicated by `perm` for the target domain indicated by the key
+/// descriptor `key` in the security class `keystore2_key`.
+///
+/// The behavior differs slightly depending on the selected target domain:
+///  * `Domain::App` u:r:keystore:s0 is used as target context.
+///  * `Domain::SELinux` `key.namespace_` parameter is looked up in the SELinux keystore key
+///                      backend, and the result is used as target context.
+///  * `Domain::Blob` Same as SELinux but the "manage_blob" permission is always checked additionally
+///                   to the one supplied in `perm`.
+///  * `Domain::Grant` Does not use selinux::check_access. Instead the `access_vector`
+///                    parameter is queried for permission, which must be supplied in this case.
+///
+/// ## Return values.
+///  * Ok(()) If the requested permissions were granted.
+///  * Err(selinux::Error::perm()) If the requested permissions were denied.
+///  * Err(KsError::sys()) This error is produced if `Domain::Grant` is selected but no `access_vec`
+///                      was supplied. It is also produced if `Domain::KeyId` was selected, and
+///                      on various unexpected backend failures.
+pub fn check_key_permission(
+    caller_ctx: &selinux::Context,
+    perm: KeyPerm,
+    key: &aidl::KeyDescriptor,
+    access_vector: &Option<KeyPermSet>,
+) -> anyhow::Result<()> {
+    use aidl::Domain;
+    use selinux::KeystoreKeyBackend;
+
+    let target_context = match key.domain {
+        // apps get the default keystore context
+        Domain::App => getcon().context("check_key_permission: getcon failed.")?,
+        Domain::SELinux => {
+            // TODO cache an open backend, possible use a lasy static.
+            let backend = KeystoreKeyBackend::new().context(
+                "check_key_permission: Domain::SELinux: Failed to create selinux keystore backend.",
+            )?;
+            backend
+                .lookup(format!("{}", key.namespace_).as_str())
+                .context("check_key_permission: Domain::SELinux: Failed to lookup namespace")?
+        }
+        Domain::Grant => {
+            match access_vector {
+                Some(pv) => {
+                    if pv.includes(perm) {
+                        return Ok(());
+                    } else {
+                        return Err(selinux::Error::perm())
+                            .context(format!("\"{}\" not granted", perm.to_selinux()));
+                    }
+                }
+                None => {
+                    // If DOMAIN_GRANT was selected an access vector must be supplied.
+                    return Err(KsError::sys()).context(
+                        "Cannot check permission for Domain::Grant without access vector.",
+                    );
+                }
+            }
+        }
+        Domain::KeyId => {
+            // We should never be called with `Domain::KeyId. The database
+            // lookup should have converted this into one of `Domain::App`
+            // or `Domain::SELinux`.
+            return Err(KsError::sys()).context("Cannot check permission for Domain::KeyId.");
+        }
+        Domain::Blob => {
+            let backend = KeystoreKeyBackend::new()
+                .context("Domain::Blob: Failed to create selinux keystore backend.")?;
+            let tctx = backend
+                .lookup(format!("{}", key.namespace_).as_str())
+                .context("Domain::Blob: Failed to lookup namespace.")?;
+            // If DOMAIN_KEY_BLOB was specified, we check for the "manage_blob"
+            // permission in addition to the requested permission.
+            selinux::check_access(
+                caller_ctx,
+                &tctx,
+                "keystore2_key",
+                KeyPerm::manage_blob().to_selinux(),
+            )?;
+
+            tctx
+        }
+    };
+
+    selinux::check_access(caller_ctx, &target_context, "keystore2_key", perm.to_selinux())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use anyhow::anyhow;
+    use anyhow::Result;
+    use keystore2_selinux::*;
+    use keystore_aidl_generated as aidl;
+
+    const ALL_PERMS: KeyPermSet = key_perm_set![
+        KeyPerm::manage_blob(),
+        KeyPerm::delete(),
+        KeyPerm::use_dev_id(),
+        KeyPerm::req_forced_op(),
+        KeyPerm::gen_unique_id(),
+        KeyPerm::grant(),
+        KeyPerm::get_info(),
+        KeyPerm::list(),
+        KeyPerm::rebind(),
+        KeyPerm::update(),
+        KeyPerm::use_(),
+    ];
+
+    const NOT_GRANT_PERMS: KeyPermSet = key_perm_set![
+        KeyPerm::manage_blob(),
+        KeyPerm::delete(),
+        KeyPerm::use_dev_id(),
+        KeyPerm::req_forced_op(),
+        KeyPerm::gen_unique_id(),
+        // No KeyPerm::grant()
+        KeyPerm::get_info(),
+        KeyPerm::list(),
+        KeyPerm::rebind(),
+        KeyPerm::update(),
+        KeyPerm::use_(),
+    ];
+
+    const UNPRIV_PERMS: KeyPermSet = key_perm_set![
+        KeyPerm::delete(),
+        KeyPerm::get_info(),
+        KeyPerm::list(),
+        KeyPerm::rebind(),
+        KeyPerm::update(),
+        KeyPerm::use_(),
+    ];
+
+    /// The su_key namespace as defined in su.te and keystore_key_contexts of the
+    /// SePolicy (system/sepolicy).
+    const SU_KEY_NAMESPACE: i32 = 0;
+    /// The shell_key namespace as defined in shell.te and keystore_key_contexts of the
+    /// SePolicy (system/sepolicy).
+    const SHELL_KEY_NAMESPACE: i32 = 1;
+
+    pub fn test_getcon() -> Result<Context> {
+        Context::new("u:object_r:keystore:s0")
+    }
+
+    // This macro evaluates the given expression and checks that
+    // a) evaluated to Result::Err() and that
+    // b) the wrapped error is selinux::Error::perm() (permission denied).
+    // We use a macro here because a function would mask which invocation caused the failure.
+    //
+    // TODO b/164121720 Replace this macro with a function when `track_caller` is available.
+    macro_rules! assert_perm_failed {
+        ($test_function:expr) => {
+            let result = $test_function;
+            assert!(result.is_err(), "Permission check should have failed.");
+            assert_eq!(
+                Some(&selinux::Error::perm()),
+                result.err().unwrap().root_cause().downcast_ref::<selinux::Error>()
+            );
+        };
+    }
+
+    fn check_context() -> Result<(selinux::Context, i32, bool)> {
+        // Calling the non mocked selinux::getcon here intended.
+        let context = selinux::getcon()?;
+        match context.to_str().unwrap() {
+            "u:r:su:s0" => Ok((context, SU_KEY_NAMESPACE, true)),
+            "u:r:shell:s0" => Ok((context, SHELL_KEY_NAMESPACE, false)),
+            c => Err(anyhow!(format!(
+                "This test must be run as \"su\" or \"shell\". Current context: \"{}\"",
+                c
+            ))),
+        }
+    }
+
+    #[test]
+    fn check_keystore_permission_test() -> Result<()> {
+        let system_server_ctx = Context::new("u:r:system_server:s0")?;
+        assert!(check_keystore_permission(&system_server_ctx, KeystorePerm::add_auth()).is_ok());
+        assert!(check_keystore_permission(&system_server_ctx, KeystorePerm::clear_ns()).is_ok());
+        assert!(check_keystore_permission(&system_server_ctx, KeystorePerm::get_state()).is_ok());
+        assert!(check_keystore_permission(&system_server_ctx, KeystorePerm::lock()).is_ok());
+        assert!(check_keystore_permission(&system_server_ctx, KeystorePerm::reset()).is_ok());
+        assert!(check_keystore_permission(&system_server_ctx, KeystorePerm::unlock()).is_ok());
+        let shell_ctx = Context::new("u:r:shell:s0")?;
+        assert_perm_failed!(check_keystore_permission(&shell_ctx, KeystorePerm::add_auth()));
+        assert_perm_failed!(check_keystore_permission(&shell_ctx, KeystorePerm::clear_ns()));
+        assert_perm_failed!(check_keystore_permission(&shell_ctx, KeystorePerm::get_state()));
+        assert_perm_failed!(check_keystore_permission(&shell_ctx, KeystorePerm::lock()));
+        assert_perm_failed!(check_keystore_permission(&shell_ctx, KeystorePerm::reset()));
+        assert_perm_failed!(check_keystore_permission(&shell_ctx, KeystorePerm::unlock()));
+        Ok(())
+    }
+
+    #[test]
+    fn check_grant_permission_app() -> Result<()> {
+        let system_server_ctx = Context::new("u:r:system_server:s0")?;
+        let shell_ctx = Context::new("u:r:shell:s0")?;
+        use aidl::Domain;
+        let key =
+            aidl::KeyDescriptor { domain: Domain::App, namespace_: 0, alias: None, blob: None };
+        assert!(check_grant_permission(&system_server_ctx, NOT_GRANT_PERMS, &key).is_ok());
+        // attempts to grant the grant permission must always fail even when privileged.
+
+        assert_perm_failed!(check_grant_permission(
+            &system_server_ctx,
+            KeyPerm::grant().into(),
+            &key
+        ));
+        // unprivileged grant attempts always fail. shell does not have the grant permission.
+        assert_perm_failed!(check_grant_permission(&shell_ctx, UNPRIV_PERMS, &key));
+        Ok(())
+    }
+
+    #[test]
+    fn check_grant_permission_selinux() -> Result<()> {
+        use aidl::Domain;
+        let (sctx, namespace, is_su) = check_context()?;
+        let key = aidl::KeyDescriptor {
+            domain: Domain::SELinux,
+            namespace_: namespace as i64,
+            alias: None,
+            blob: None,
+        };
+        if is_su {
+            assert!(check_grant_permission(&sctx, NOT_GRANT_PERMS, &key).is_ok());
+            // attempts to grant the grant permission must always fail even when privileged.
+            assert_perm_failed!(check_grant_permission(&sctx, KeyPerm::grant().into(), &key));
+        } else {
+            // unprivileged grant attempts always fail. shell does not have the grant permission.
+            assert_perm_failed!(check_grant_permission(&sctx, UNPRIV_PERMS, &key));
+        }
+        Ok(())
+    }
+
+    #[test]
+    fn check_key_permission_domain_grant() -> Result<()> {
+        use aidl::Domain;
+        let key =
+            aidl::KeyDescriptor { domain: Domain::Grant, namespace_: 0, alias: None, blob: None };
+
+        assert_perm_failed!(check_key_permission(
+            &selinux::Context::new("ignored").unwrap(),
+            KeyPerm::grant(),
+            &key,
+            &Some(UNPRIV_PERMS)
+        ));
+
+        check_key_permission(
+            &selinux::Context::new("ignored").unwrap(),
+            KeyPerm::use_(),
+            &key,
+            &Some(ALL_PERMS),
+        )
+    }
+
+    #[test]
+    fn check_key_permission_domain_app() -> Result<()> {
+        let system_server_ctx = Context::new("u:r:system_server:s0")?;
+        let shell_ctx = Context::new("u:r:shell:s0")?;
+        let gmscore_app = Context::new("u:r:gmscore_app:s0")?;
+        use aidl::Domain;
+
+        let key =
+            aidl::KeyDescriptor { domain: Domain::App, namespace_: 0, alias: None, blob: None };
+
+        assert!(check_key_permission(&system_server_ctx, KeyPerm::use_(), &key, &None).is_ok());
+        assert!(check_key_permission(&system_server_ctx, KeyPerm::delete(), &key, &None).is_ok());
+        assert!(check_key_permission(&system_server_ctx, KeyPerm::get_info(), &key, &None).is_ok());
+        assert!(check_key_permission(&system_server_ctx, KeyPerm::rebind(), &key, &None).is_ok());
+        assert!(check_key_permission(&system_server_ctx, KeyPerm::list(), &key, &None).is_ok());
+        assert!(check_key_permission(&system_server_ctx, KeyPerm::update(), &key, &None).is_ok());
+        assert!(check_key_permission(&system_server_ctx, KeyPerm::grant(), &key, &None).is_ok());
+        assert!(
+            check_key_permission(&system_server_ctx, KeyPerm::use_dev_id(), &key, &None).is_ok()
+        );
+        assert!(check_key_permission(&gmscore_app, KeyPerm::gen_unique_id(), &key, &None).is_ok());
+
+        assert!(check_key_permission(&shell_ctx, KeyPerm::use_(), &key, &None).is_ok());
+        assert!(check_key_permission(&shell_ctx, KeyPerm::delete(), &key, &None).is_ok());
+        assert!(check_key_permission(&shell_ctx, KeyPerm::get_info(), &key, &None).is_ok());
+        assert!(check_key_permission(&shell_ctx, KeyPerm::rebind(), &key, &None).is_ok());
+        assert!(check_key_permission(&shell_ctx, KeyPerm::list(), &key, &None).is_ok());
+        assert!(check_key_permission(&shell_ctx, KeyPerm::update(), &key, &None).is_ok());
+        assert_perm_failed!(check_key_permission(&shell_ctx, KeyPerm::grant(), &key, &None));
+        assert_perm_failed!(check_key_permission(
+            &shell_ctx,
+            KeyPerm::req_forced_op(),
+            &key,
+            &None
+        ));
+        assert_perm_failed!(check_key_permission(&shell_ctx, KeyPerm::manage_blob(), &key, &None));
+        assert_perm_failed!(check_key_permission(&shell_ctx, KeyPerm::use_dev_id(), &key, &None));
+        assert_perm_failed!(check_key_permission(
+            &shell_ctx,
+            KeyPerm::gen_unique_id(),
+            &key,
+            &None
+        ));
+
+        Ok(())
+    }
+
+    #[test]
+    fn check_key_permission_domain_selinux() -> Result<()> {
+        use aidl::Domain;
+        let (sctx, namespace, is_su) = check_context()?;
+        let key = aidl::KeyDescriptor {
+            domain: Domain::SELinux,
+            namespace_: namespace as i64,
+            alias: None,
+            blob: None,
+        };
+
+        if is_su {
+            assert!(check_key_permission(&sctx, KeyPerm::use_(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::delete(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::get_info(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::rebind(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::list(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::update(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::grant(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::manage_blob(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::use_dev_id(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::gen_unique_id(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::req_forced_op(), &key, &None).is_ok());
+        } else {
+            assert!(check_key_permission(&sctx, KeyPerm::use_(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::delete(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::get_info(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::rebind(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::list(), &key, &None).is_ok());
+            assert!(check_key_permission(&sctx, KeyPerm::update(), &key, &None).is_ok());
+            assert_perm_failed!(check_key_permission(&sctx, KeyPerm::grant(), &key, &None));
+            assert_perm_failed!(check_key_permission(&sctx, KeyPerm::req_forced_op(), &key, &None));
+            assert_perm_failed!(check_key_permission(&sctx, KeyPerm::manage_blob(), &key, &None));
+            assert_perm_failed!(check_key_permission(&sctx, KeyPerm::use_dev_id(), &key, &None));
+            assert_perm_failed!(check_key_permission(&sctx, KeyPerm::gen_unique_id(), &key, &None));
+        }
+        Ok(())
+    }
+
+    #[test]
+    fn check_key_permission_domain_blob() -> Result<()> {
+        use aidl::Domain;
+        let (sctx, namespace, is_su) = check_context()?;
+        let key = aidl::KeyDescriptor {
+            domain: Domain::Blob,
+            namespace_: namespace as i64,
+            alias: None,
+            blob: None,
+        };
+
+        if is_su {
+            check_key_permission(&sctx, KeyPerm::use_(), &key, &None)
+        } else {
+            assert_perm_failed!(check_key_permission(&sctx, KeyPerm::use_(), &key, &None));
+            Ok(())
+        }
+    }
+
+    #[test]
+    fn check_key_permission_domain_key_id() -> Result<()> {
+        use aidl::Domain;
+        let key =
+            aidl::KeyDescriptor { domain: Domain::KeyId, namespace_: 0, alias: None, blob: None };
+
+        assert_eq!(
+            Some(&KsError::sys()),
+            check_key_permission(
+                &selinux::Context::new("ignored").unwrap(),
+                KeyPerm::use_(),
+                &key,
+                &None
+            )
+            .err()
+            .unwrap()
+            .root_cause()
+            .downcast_ref::<KsError>()
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn key_perm_set_all_test() {
+        let v = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::delete(),
+            KeyPerm::use_dev_id(),
+            KeyPerm::req_forced_op(),
+            KeyPerm::gen_unique_id(),
+            KeyPerm::grant(),
+            KeyPerm::get_info(),
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_() // Test if the macro accepts missing comma at the end of the list.
+        ];
+        let mut i = v.into_iter();
+        assert_eq!(i.next().unwrap().to_selinux(), "delete");
+        assert_eq!(i.next().unwrap().to_selinux(), "gen_unique_id");
+        assert_eq!(i.next().unwrap().to_selinux(), "get_info");
+        assert_eq!(i.next().unwrap().to_selinux(), "grant");
+        assert_eq!(i.next().unwrap().to_selinux(), "list");
+        assert_eq!(i.next().unwrap().to_selinux(), "manage_blob");
+        assert_eq!(i.next().unwrap().to_selinux(), "rebind");
+        assert_eq!(i.next().unwrap().to_selinux(), "req_forced_op");
+        assert_eq!(i.next().unwrap().to_selinux(), "update");
+        assert_eq!(i.next().unwrap().to_selinux(), "use");
+        assert_eq!(i.next().unwrap().to_selinux(), "use_dev_id");
+        assert_eq!(None, i.next());
+    }
+    #[test]
+    fn key_perm_set_sparse_test() {
+        let v = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::req_forced_op(),
+            KeyPerm::gen_unique_id(),
+            KeyPerm::list(),
+            KeyPerm::update(),
+            KeyPerm::use_(), // Test if macro accepts the comma at the end of the list.
+        ];
+        let mut i = v.into_iter();
+        assert_eq!(i.next().unwrap().to_selinux(), "gen_unique_id");
+        assert_eq!(i.next().unwrap().to_selinux(), "list");
+        assert_eq!(i.next().unwrap().to_selinux(), "manage_blob");
+        assert_eq!(i.next().unwrap().to_selinux(), "req_forced_op");
+        assert_eq!(i.next().unwrap().to_selinux(), "update");
+        assert_eq!(i.next().unwrap().to_selinux(), "use");
+        assert_eq!(None, i.next());
+    }
+    #[test]
+    fn key_perm_set_empty_test() {
+        let v = key_perm_set![];
+        let mut i = v.into_iter();
+        assert_eq!(None, i.next());
+    }
+    #[test]
+    fn key_perm_set_include_subset_test() {
+        let v1 = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::delete(),
+            KeyPerm::use_dev_id(),
+            KeyPerm::req_forced_op(),
+            KeyPerm::gen_unique_id(),
+            KeyPerm::grant(),
+            KeyPerm::get_info(),
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_(),
+        ];
+        let v2 = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::delete(),
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_(),
+        ];
+        assert!(v1.includes(v2));
+        assert!(!v2.includes(v1));
+    }
+    #[test]
+    fn key_perm_set_include_equal_test() {
+        let v1 = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::delete(),
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_(),
+        ];
+        let v2 = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::delete(),
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_(),
+        ];
+        assert!(v1.includes(v2));
+        assert!(v2.includes(v1));
+    }
+    #[test]
+    fn key_perm_set_include_overlap_test() {
+        let v1 = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::delete(),
+            KeyPerm::grant(), // only in v1
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_(),
+        ];
+        let v2 = key_perm_set![
+            KeyPerm::manage_blob(),
+            KeyPerm::delete(),
+            KeyPerm::req_forced_op(), // only in v2
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_(),
+        ];
+        assert!(!v1.includes(v2));
+        assert!(!v2.includes(v1));
+    }
+    #[test]
+    fn key_perm_set_include_no_overlap_test() {
+        let v1 = key_perm_set![KeyPerm::manage_blob(), KeyPerm::delete(), KeyPerm::grant(),];
+        let v2 = key_perm_set![
+            KeyPerm::req_forced_op(),
+            KeyPerm::list(),
+            KeyPerm::rebind(),
+            KeyPerm::update(),
+            KeyPerm::use_(),
+        ];
+        assert!(!v1.includes(v2));
+        assert!(!v2.includes(v1));
+    }
+}