| From 5bce943cdb8fc81525257413f174844d644d63c8 Mon Sep 17 00:00:00 2001 |
| From: Eric Biggers <ebiggers@google.com> |
| Date: Tue, 20 Apr 2021 16:48:07 -0700 |
| Subject: [PATCH] Use /dev/urandom instead of getrandom() |
| |
| To generate the ahash crate's default hash keys, use /dev/urandom |
| instead of getrandom() to avoid blocking boot on systems where the |
| entropy pool isn't initialized in time and where the use case of this |
| crate doesn't actually require cryptographic randomness. |
| |
| If opening or reading from /dev/urandom fails, fall back to getrandom(). |
| |
| Note that std::collections::HashMap doesn't block for randomness either, |
| for the same reason. So this change just makes ahash work like HashMap. |
| |
| Bug: 185934601 |
| Change-Id: Ie81a1f3a893d578348db11aee114d1a8f2d9fac5 |
| --- |
| diff --git a/src/random_state.rs b/src/random_state.rs |
| index 501e3eb..9b3b3d0 100644 |
| --- a/src/random_state.rs |
| +++ b/src/random_state.rs |
| @@ -10,11 +10,22 @@ use core::hash::Hasher; |
| use lazy_static::*; |
| use core::sync::atomic::{AtomicUsize, Ordering}; |
| |
| +#[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))] |
| +fn read_urandom(dest: &mut [u8]) -> Result<(), std::io::Error> { |
| + use std::fs::File; |
| + use std::io::Read; |
| + |
| + let mut f = File::open("/dev/urandom")?; |
| + f.read_exact(dest) |
| +} |
| + |
| #[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))] |
| lazy_static! { |
| static ref SEEDS: [[u64; 4]; 2] = { |
| let mut result: [u8; 64] = [0; 64]; |
| - getrandom::getrandom(&mut result).expect("getrandom::getrandom() failed."); |
| + if read_urandom(&mut result).is_err() { |
| + getrandom::getrandom(&mut result).expect("getrandom::getrandom() failed.") |
| + } |
| result.convert() |
| }; |
| } |
| -- |
| 2.31.1.498.g6c1eba8ee3d-goog |
| |