diff options
-rw-r--r-- | patches/0001-Use-dev-urandom-instead-of-getrandom.patch | 49 | ||||
-rw-r--r-- | src/random_state.rs | 13 |
2 files changed, 61 insertions, 1 deletions
diff --git a/patches/0001-Use-dev-urandom-instead-of-getrandom.patch b/patches/0001-Use-dev-urandom-instead-of-getrandom.patch new file mode 100644 index 0000000..d5adff0 --- /dev/null +++ b/patches/0001-Use-dev-urandom-instead-of-getrandom.patch @@ -0,0 +1,49 @@ +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 + 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 @@ -11,10 +11,21 @@ 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() }; } |