src/crypto/rng.rs

//
// Copyright (C) 2024 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.

use crate::invoke::{Param, Ta, PTA_SYSTEM_ADD_RNG_ENTROPY};
use kmr_common::crypto;
use optee_utee::Random;

pub struct Rng;

impl Rng {
    fn add_rng_entropy(&self, data: &[u8]) -> Result<(), kmr_common::Error> {
        if data.len() == 0 {
            return Ok(());
        }

        let mut params = Param::empty();
        let session = Ta::open_system_pta(&params)?;

        params.0 = Param::from_slice(data);
        session.invoke(PTA_SYSTEM_ADD_RNG_ENTROPY, &params)?;

        Ok(())
    }
}

impl crypto::Rng for Rng {
    fn add_entropy(&mut self, data: &[u8]) {
        let _ = self.add_rng_entropy(data);
    }

    fn fill_bytes(&mut self, dest: &mut [u8]) {
        Random::generate(dest);
    }
}