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// Copyright 2021, 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 module implements IKeystoreMaintenance AIDL interface.
use crate::error::map_km_error;
use crate::error::Error as KeystoreError;
use crate::globals::get_keymint_device;
use crate::globals::{DB, LEGACY_MIGRATOR, SUPER_KEY};
use crate::permission::KeystorePerm;
use crate::super_key::UserState;
use crate::utils::check_keystore_permission;
use crate::{database::MonotonicRawTime, error::map_or_log_err};
use android_hardware_security_keymint::aidl::android::hardware::security::keymint::IKeyMintDevice::IKeyMintDevice;
use android_hardware_security_keymint::aidl::android::hardware::security::keymint::SecurityLevel::SecurityLevel;
use android_security_maintenance::aidl::android::security::maintenance::{
IKeystoreMaintenance::{BnKeystoreMaintenance, IKeystoreMaintenance},
UserState::UserState as AidlUserState,
};
use android_security_maintenance::binder::{Interface, Result as BinderResult};
use android_system_keystore2::aidl::android::system::keystore2::Domain::Domain;
use android_system_keystore2::aidl::android::system::keystore2::ResponseCode::ResponseCode;
use anyhow::{Context, Result};
use binder::{IBinderInternal, Strong};
use keystore2_crypto::Password;
/// This struct is defined to implement the aforementioned AIDL interface.
/// As of now, it is an empty struct.
pub struct Maintenance;
impl Maintenance {
/// Create a new instance of Keystore User Manager service.
pub fn new_native_binder() -> Result<Strong<dyn IKeystoreMaintenance>> {
let result = BnKeystoreMaintenance::new_binder(Self);
result.as_binder().set_requesting_sid(true);
Ok(result)
}
fn on_user_password_changed(user_id: i32, password: Option<Password>) -> Result<()> {
//Check permission. Function should return if this failed. Therefore having '?' at the end
//is very important.
check_keystore_permission(KeystorePerm::change_password())
.context("In on_user_password_changed.")?;
if let Some(pw) = password.as_ref() {
DB.with(|db| {
SUPER_KEY.unlock_screen_lock_bound_key(&mut db.borrow_mut(), user_id as u32, pw)
})
.context("In on_user_password_changed: unlock_screen_lock_bound_key failed")?;
}
match DB
.with(|db| {
UserState::get_with_password_changed(
&mut db.borrow_mut(),
&LEGACY_MIGRATOR,
&SUPER_KEY,
user_id as u32,
password.as_ref(),
)
})
.context("In on_user_password_changed.")?
{
UserState::LskfLocked => {
// Error - password can not be changed when the device is locked
Err(KeystoreError::Rc(ResponseCode::LOCKED))
.context("In on_user_password_changed. Device is locked.")
}
_ => {
// LskfLocked is the only error case for password change
Ok(())
}
}
}
fn add_or_remove_user(user_id: i32) -> Result<()> {
// Check permission. Function should return if this failed. Therefore having '?' at the end
// is very important.
check_keystore_permission(KeystorePerm::change_user()).context("In add_or_remove_user.")?;
DB.with(|db| {
UserState::reset_user(
&mut db.borrow_mut(),
&SUPER_KEY,
&LEGACY_MIGRATOR,
user_id as u32,
false,
)
})
.context("In add_or_remove_user: Trying to delete keys from db.")
}
fn clear_namespace(domain: Domain, nspace: i64) -> Result<()> {
// Permission check. Must return on error. Do not touch the '?'.
check_keystore_permission(KeystorePerm::clear_uid()).context("In clear_namespace.")?;
LEGACY_MIGRATOR
.bulk_delete_uid(domain, nspace)
.context("In clear_namespace: Trying to delete legacy keys.")?;
DB.with(|db| db.borrow_mut().unbind_keys_for_namespace(domain, nspace))
.context("In clear_namespace: Trying to delete keys from db.")
}
fn get_state(user_id: i32) -> Result<AidlUserState> {
// Check permission. Function should return if this failed. Therefore having '?' at the end
// is very important.
check_keystore_permission(KeystorePerm::get_state()).context("In get_state.")?;
let state = DB
.with(|db| {
UserState::get(&mut db.borrow_mut(), &LEGACY_MIGRATOR, &SUPER_KEY, user_id as u32)
})
.context("In get_state. Trying to get UserState.")?;
match state {
UserState::Uninitialized => Ok(AidlUserState::UNINITIALIZED),
UserState::LskfUnlocked(_) => Ok(AidlUserState::LSKF_UNLOCKED),
UserState::LskfLocked => Ok(AidlUserState::LSKF_LOCKED),
}
}
fn early_boot_ended_help(sec_level: &SecurityLevel) -> Result<()> {
let (dev, _, _) =
get_keymint_device(sec_level).context("In early_boot_ended: getting keymint device")?;
let km_dev: Strong<dyn IKeyMintDevice> =
dev.get_interface().context("In early_boot_ended: getting keymint device interface")?;
map_km_error(km_dev.earlyBootEnded())
.context("In keymint device: calling earlyBootEnded")?;
Ok(())
}
fn early_boot_ended() -> Result<()> {
check_keystore_permission(KeystorePerm::early_boot_ended())
.context("In early_boot_ended. Checking permission")?;
log::info!("In early_boot_ended.");
if let Err(e) = DB.with(|db| SUPER_KEY.set_up_boot_level_cache(&mut db.borrow_mut())) {
log::error!("SUPER_KEY.set_up_boot_level_cache failed:\n{:?}\n:(", e);
}
let sec_levels = [
(SecurityLevel::TRUSTED_ENVIRONMENT, "TRUSTED_ENVIRONMENT"),
(SecurityLevel::STRONGBOX, "STRONGBOX"),
];
sec_levels.iter().fold(Ok(()), |result, (sec_level, sec_level_string)| {
let curr_result = Maintenance::early_boot_ended_help(sec_level);
if curr_result.is_err() {
log::error!(
"Call to earlyBootEnded failed for security level {}.",
&sec_level_string
);
}
result.and(curr_result)
})
}
fn on_device_off_body() -> Result<()> {
// Security critical permission check. This statement must return on fail.
check_keystore_permission(KeystorePerm::report_off_body())
.context("In on_device_off_body.")?;
DB.with(|db| db.borrow_mut().update_last_off_body(MonotonicRawTime::now()))
.context("In on_device_off_body: Trying to update last off body time.")
}
}
impl Interface for Maintenance {}
impl IKeystoreMaintenance for Maintenance {
fn onUserPasswordChanged(&self, user_id: i32, password: Option<&[u8]>) -> BinderResult<()> {
map_or_log_err(Self::on_user_password_changed(user_id, password.map(|pw| pw.into())), Ok)
}
fn onUserAdded(&self, user_id: i32) -> BinderResult<()> {
map_or_log_err(Self::add_or_remove_user(user_id), Ok)
}
fn onUserRemoved(&self, user_id: i32) -> BinderResult<()> {
map_or_log_err(Self::add_or_remove_user(user_id), Ok)
}
fn clearNamespace(&self, domain: Domain, nspace: i64) -> BinderResult<()> {
map_or_log_err(Self::clear_namespace(domain, nspace), Ok)
}
fn getState(&self, user_id: i32) -> BinderResult<AidlUserState> {
map_or_log_err(Self::get_state(user_id), Ok)
}
fn earlyBootEnded(&self) -> BinderResult<()> {
map_or_log_err(Self::early_boot_ended(), Ok)
}
fn onDeviceOffBody(&self) -> BinderResult<()> {
map_or_log_err(Self::on_device_off_body(), Ok)
}
}
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