1 // Copyright 2022, The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 //! BoringSSL-based implementation of random number generation.
16 #[cfg(soong)]
17 use bssl_sys as ffi;
18 use kmr_common::crypto;
19 
20 /// [`crypto::Rng`] implementation based on BoringSSL.
21 #[derive(Default)]
22 pub struct BoringRng;
23 
24 impl crypto::Rng for BoringRng {
add_entropy(&mut self, data: &[u8])25     fn add_entropy(&mut self, data: &[u8]) {
26         #[cfg(soong)]
27         // Safety: `data` is a valid slice.
28         unsafe {
29             ffi::RAND_seed(data.as_ptr() as *const libc::c_void, data.len() as libc::c_int);
30         }
31         #[cfg(not(soong))]
32         // Safety: `data` is a valid slice.
33         unsafe {
34             ffi::RAND_add(
35                 data.as_ptr() as *const libc::c_void,
36                 data.len() as libc::c_int,
37                 data.len() as f64,
38             );
39         }
40     }
fill_bytes(&mut self, dest: &mut [u8])41     fn fill_bytes(&mut self, dest: &mut [u8]) {
42         openssl::rand::rand_bytes(dest).unwrap(); // safe: BoringSSL's RAND_bytes() never fails
43     }
44 }
45