Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 1 | // Copyright (C) 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 | //! FIPS compliant random number conditioner. Reads from /dev/hw_random |
| 16 | //! and applies the NIST SP 800-90A CTR DRBG strategy to provide |
| 17 | //! pseudorandom bytes to clients which connect to a socket provided |
| 18 | //! by init. |
| 19 | |
| 20 | mod conditioner; |
| 21 | mod cutils_socket; |
| 22 | mod drbg; |
| 23 | |
| 24 | use std::{ |
| 25 | convert::Infallible, |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 26 | fs::remove_file, |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 27 | io::ErrorKind, |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 28 | os::unix::net::UnixListener, |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 29 | path::{Path, PathBuf}, |
| 30 | }; |
| 31 | |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 32 | use anyhow::{ensure, Context, Result}; |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 33 | use clap::Parser; |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 34 | use log::{error, info, Level}; |
| 35 | use nix::sys::signal; |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 36 | use tokio::{io::AsyncWriteExt, net::UnixListener as TokioUnixListener}; |
| 37 | |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 38 | use crate::conditioner::ConditionerBuilder; |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 39 | |
| 40 | #[derive(Debug, clap::Parser)] |
| 41 | struct Cli { |
| 42 | #[clap(long, default_value = "/dev/hw_random")] |
| 43 | source: PathBuf, |
| 44 | #[clap(long)] |
| 45 | socket: Option<PathBuf>, |
| 46 | } |
| 47 | |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 48 | fn configure_logging() -> Result<()> { |
| 49 | ensure!( |
| 50 | logger::init( |
| 51 | logger::Config::default().with_tag_on_device("prng_seeder").with_min_level(Level::Info) |
| 52 | ), |
| 53 | "log configuration failed" |
| 54 | ); |
| 55 | Ok(()) |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 56 | } |
| 57 | |
| 58 | fn get_socket(path: &Path) -> Result<UnixListener> { |
| 59 | if let Err(e) = remove_file(path) { |
| 60 | if e.kind() != ErrorKind::NotFound { |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 61 | return Err(e).context(format!("Removing old socket: {}", path.display())); |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 62 | } |
| 63 | } else { |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 64 | info!("Deleted old {}", path.display()); |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 65 | } |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 66 | UnixListener::bind(path) |
| 67 | .with_context(|| format!("In get_socket: binding socket to {}", path.display())) |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 68 | } |
| 69 | |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 70 | fn setup() -> Result<(ConditionerBuilder, UnixListener)> { |
| 71 | configure_logging()?; |
| 72 | let cli = Cli::try_parse()?; |
| 73 | unsafe { signal::signal(signal::Signal::SIGPIPE, signal::SigHandler::SigIgn) } |
| 74 | .context("In setup, setting SIGPIPE to SIG_IGN")?; |
| 75 | |
| 76 | let listener = match cli.socket { |
| 77 | Some(path) => get_socket(path.as_path())?, |
| 78 | None => cutils_socket::android_get_control_socket("prng_seeder") |
| 79 | .context("In setup, calling android_get_control_socket")?, |
| 80 | }; |
| 81 | let hwrng = std::fs::File::open(&cli.source) |
| 82 | .with_context(|| format!("Unable to open hwrng {}", cli.source.display()))?; |
| 83 | let cb = ConditionerBuilder::new(hwrng)?; |
| 84 | Ok((cb, listener)) |
| 85 | } |
| 86 | |
| 87 | async fn listen_loop(cb: ConditionerBuilder, listener: UnixListener) -> Result<Infallible> { |
| 88 | let mut conditioner = cb.build(); |
| 89 | listener.set_nonblocking(true).context("In listen_loop, on set_nonblocking")?; |
| 90 | let listener = TokioUnixListener::from_std(listener).context("In listen_loop, on from_std")?; |
| 91 | info!("Starting listen loop"); |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 92 | loop { |
| 93 | match listener.accept().await { |
| 94 | Ok((mut stream, _)) => { |
| 95 | let new_bytes = conditioner.request()?; |
| 96 | tokio::spawn(async move { |
| 97 | if let Err(e) = stream.write_all(&new_bytes).await { |
| 98 | error!("Request failed: {}", e); |
| 99 | } |
| 100 | }); |
| 101 | conditioner.reseed_if_necessary().await?; |
| 102 | } |
| 103 | Err(e) if e.kind() == ErrorKind::Interrupted => {} |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 104 | Err(e) => return Err(e).context("accept on socket failed"), |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 105 | } |
| 106 | } |
| 107 | } |
| 108 | |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 109 | fn run() -> Result<Infallible> { |
| 110 | let (cb, listener) = match setup() { |
| 111 | Ok(t) => t, |
| 112 | Err(e) => { |
| 113 | // If setup fails, just hang forever. That way init doesn't respawn us. |
| 114 | error!("Hanging forever because setup failed: {:?}", e); |
| 115 | // Logs are sometimes mysteriously not being logged, so print too |
| 116 | println!("prng_seeder: Hanging forever because setup failed: {:?}", e); |
| 117 | loop { |
| 118 | std::thread::park(); |
| 119 | error!("std::thread::park() finished unexpectedly, re-parking thread"); |
| 120 | } |
| 121 | } |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 122 | }; |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 123 | |
| 124 | tokio::runtime::Builder::new_current_thread() |
| 125 | .enable_all() |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 126 | .build() |
| 127 | .context("In run, building reactor")? |
| 128 | .block_on(async { listen_loop(cb, listener).await }) |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 129 | } |
| 130 | |
| 131 | fn main() { |
Paul Crowley | 021cf55 | 2022-09-28 18:37:43 +0000 | [diff] [blame] | 132 | let e = run(); |
| 133 | error!("Launch terminated: {:?}", e); |
| 134 | // Logs are sometimes mysteriously not being logged, so print too |
| 135 | println!("prng_seeder: launch terminated: {:?}", e); |
Paul Crowley | 9da969e | 2022-09-16 23:42:24 +0000 | [diff] [blame] | 136 | std::process::exit(-1); |
| 137 | } |