From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- vendor/getrandom-0.1.14/src/rdrand.rs | 90 +++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 vendor/getrandom-0.1.14/src/rdrand.rs (limited to 'vendor/getrandom-0.1.14/src/rdrand.rs') diff --git a/vendor/getrandom-0.1.14/src/rdrand.rs b/vendor/getrandom-0.1.14/src/rdrand.rs new file mode 100644 index 000000000..e4416821b --- /dev/null +++ b/vendor/getrandom-0.1.14/src/rdrand.rs @@ -0,0 +1,90 @@ +// Copyright 2018 Developers of the Rand project. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! Implementation for SGX using RDRAND instruction +use crate::error::{FAILED_RDRAND, NO_RDRAND}; +#[cfg(not(target_feature = "rdrand"))] +use crate::util::LazyBool; +use crate::Error; +use core::arch::x86_64::_rdrand64_step; +use core::mem; + +// Recommendation from "Intel® Digital Random Number Generator (DRNG) Software +// Implementation Guide" - Section 5.2.1 and "Intel® 64 and IA-32 Architectures +// Software Developer’s Manual" - Volume 1 - Section 7.3.17.1. +const RETRY_LIMIT: usize = 10; +const WORD_SIZE: usize = mem::size_of::(); + +#[target_feature(enable = "rdrand")] +unsafe fn rdrand() -> Result<[u8; WORD_SIZE], Error> { + for _ in 0..RETRY_LIMIT { + let mut el = mem::zeroed(); + if _rdrand64_step(&mut el) == 1 { + // AMD CPUs from families 14h to 16h (pre Ryzen) sometimes fail to + // set CF on bogus random data, so we check these values explicitly. + // See https://github.com/systemd/systemd/issues/11810#issuecomment-489727505 + // We perform this check regardless of target to guard against + // any implementation that incorrectly fails to set CF. + if el != 0 && el != !0 { + return Ok(el.to_ne_bytes()); + } + error!("RDRAND returned {:X}, CPU RNG may be broken", el); + // Keep looping in case this was a false positive. + } + } + Err(FAILED_RDRAND) +} + +// "rdrand" target feature requires "+rdrnd" flag, see https://github.com/rust-lang/rust/issues/49653. +#[cfg(all(target_env = "sgx", not(target_feature = "rdrand")))] +compile_error!( + "SGX targets require 'rdrand' target feature. Enable by using -C target-feature=+rdrnd." +); + +#[cfg(target_feature = "rdrand")] +fn is_rdrand_supported() -> bool { + true +} + +// TODO use is_x86_feature_detected!("rdrand") when that works in core. See: +// https://github.com/rust-lang-nursery/stdsimd/issues/464 +#[cfg(not(target_feature = "rdrand"))] +fn is_rdrand_supported() -> bool { + use core::arch::x86_64::__cpuid; + // SAFETY: All x86_64 CPUs support CPUID leaf 1 + const FLAG: u32 = 1 << 30; + static HAS_RDRAND: LazyBool = LazyBool::new(); + HAS_RDRAND.unsync_init(|| unsafe { (__cpuid(1).ecx & FLAG) != 0 }) +} + +pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> { + if !is_rdrand_supported() { + return Err(NO_RDRAND); + } + + // SAFETY: After this point, rdrand is supported, so calling the rdrand + // functions is not undefined behavior. + unsafe { rdrand_exact(dest) } +} + +#[target_feature(enable = "rdrand")] +unsafe fn rdrand_exact(dest: &mut [u8]) -> Result<(), Error> { + // We use chunks_exact_mut instead of chunks_mut as it allows almost all + // calls to memcpy to be elided by the compiler. + let mut chunks = dest.chunks_exact_mut(WORD_SIZE); + for chunk in chunks.by_ref() { + chunk.copy_from_slice(&rdrand()?); + } + + let tail = chunks.into_remainder(); + let n = tail.len(); + if n > 0 { + tail.copy_from_slice(&rdrand()?[..n]); + } + Ok(()) +} -- cgit v1.2.3