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std: implement the random feature

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Implements the ACP https://github.com/rust-lang/libs-team/issues/393.
This commit is contained in:
joboet 2024-08-15 13:28:02 +02:00
parent 702987f75b
commit 5c1c725724
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GPG Key ID: 704E0149B0194B3C
43 changed files with 786 additions and 464 deletions
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2
library/core/src/lib.rs
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@ -394,6 +394,8 @@ pub mod assert_matches {
#[unstable(feature = "core_pattern_types", issue = "123646")]
pub mod pat;
pub mod pin;
#[unstable(feature = "random", issue = "none")]
pub mod random;
#[unstable(feature = "new_range_api", issue = "125687")]
pub mod range;
pub mod result;

62
library/core/src/random.rs Normal file
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@ -0,0 +1,62 @@
//! Random value generation.
//!
//! The [`Random`] trait allows generating a random value for a type using a
//! given [`RandomSource`].
/// A source of randomness.
#[unstable(feature = "random", issue = "none")]
pub trait RandomSource {
/// Fills `bytes` with random bytes.
fn fill_bytes(&mut self, bytes: &mut [u8]);
}
/// A trait for getting a random value for a type.
///
/// **Warning:** Be careful when manipulating random values! The
/// [`random`](Random::random) method on integers samples them with a uniform
/// distribution, so a value of 1 is just as likely as [`i32::MAX`]. By using
/// modulo operations, some of the resulting values can become more likely than
/// others. Use audited crates when in doubt.
#[unstable(feature = "random", issue = "none")]
pub trait Random: Sized {
/// Generates a random value.
fn random(source: &mut (impl RandomSource + ?Sized)) -> Self;
}
impl Random for bool {
fn random(source: &mut (impl RandomSource + ?Sized)) -> Self {
u8::random(source) & 1 == 1
}
}
macro_rules! impl_primitive {
($t:ty) => {
impl Random for $t {
/// Generates a random value.
///
/// **Warning:** Be careful when manipulating the resulting value! This
/// method samples according to a uniform distribution, so a value of 1 is
/// just as likely as [`MAX`](Self::MAX). By using modulo operations, some
/// values can become more likely than others. Use audited crates when in
/// doubt.
fn random(source: &mut (impl RandomSource + ?Sized)) -> Self {
let mut bytes = (0 as Self).to_ne_bytes();
source.fill_bytes(&mut bytes);
Self::from_ne_bytes(bytes)
}
}
};
}
impl_primitive!(u8);
impl_primitive!(i8);
impl_primitive!(u16);
impl_primitive!(i16);
impl_primitive!(u32);
impl_primitive!(i32);
impl_primitive!(u64);
impl_primitive!(i64);
impl_primitive!(u128);
impl_primitive!(i128);
impl_primitive!(usize);
impl_primitive!(isize);

5
library/std/src/hash/random.rs
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@ -10,7 +10,8 @@
#[allow(deprecated)]
use super::{BuildHasher, Hasher, SipHasher13};
use crate::cell::Cell;
use crate::{fmt, sys};
use crate::fmt;
use crate::sys::random::hashmap_random_keys;
/// `RandomState` is the default state for [`HashMap`] types.
///
@ -65,7 +66,7 @@ pub fn new() -> RandomState {
// increment one of the seeds on every RandomState creation, giving
// every corresponding HashMap a different iteration order.
thread_local!(static KEYS: Cell<(u64, u64)> = {
Cell::new(sys::hashmap_random_keys())
Cell::new(hashmap_random_keys())
});
KEYS.with(|keys| {

4
library/std/src/lib.rs
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@ -318,6 +318,7 @@
//
// Library features (core):
// tidy-alphabetical-start
#![feature(array_chunks)]
#![feature(c_str_module)]
#![feature(char_internals)]
#![feature(clone_to_uninit)]
@ -348,6 +349,7 @@
#![feature(prelude_2024)]
#![feature(ptr_as_uninit)]
#![feature(ptr_mask)]
#![feature(random)]
#![feature(slice_internals)]
#![feature(slice_ptr_get)]
#![feature(slice_range)]
@ -595,6 +597,8 @@
#[unstable(feature = "anonymous_pipe", issue = "127154")]
pub mod pipe;
pub mod process;
#[unstable(feature = "random", issue = "none")]
pub mod random;
pub mod sync;
pub mod time;

100
library/std/src/random.rs Normal file
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@ -0,0 +1,100 @@
//! Random value generation.
//!
//! The [`Random`] trait allows generating a random value for a type using a
//! given [`RandomSource`].
#[unstable(feature = "random", issue = "none")]
pub use core::random::*;
use crate::sys::random as sys;
/// The default random source.
///
/// This asks the system for random data suitable for cryptographic purposes
/// such as key generation. If security is a concern, consult the platform
/// documentation below for the specific guarantees your target provides.
///
/// The high quality of randomness provided by this source means it can be quite
/// slow. If you need a large quantity of random numbers and security is not a
/// concern, consider using an alternative random number generator (potentially
/// seeded from this one).
///
/// # Underlying sources
///
/// Platform | Source
/// -----------------------|---------------------------------------------------------------
/// Linux | [`getrandom`] or [`/dev/urandom`] after polling `/dev/random`
/// Windows | [`ProcessPrng`]
/// macOS and other UNIXes | [`getentropy`]
/// other Apple platforms | `CCRandomGenerateBytes`
/// ESP-IDF | [`esp_fill_random`]
/// Fuchsia | [`cprng_draw`]
/// Hermit | `read_entropy`
/// Horizon | `getrandom` shim
/// Hurd, L4Re, QNX | `/dev/urandom`
/// NetBSD before 10.0 | [`kern.arandom`]
/// Redox | `/scheme/rand`
/// SGX | [`rdrand`]
/// SOLID | `SOLID_RNG_SampleRandomBytes`
/// TEEOS | `TEE_GenerateRandom`
/// UEFI | [`EFI_RNG_PROTOCOL`]
/// VxWorks | `randABytes` after waiting for `randSecure` to become ready
/// WASI | `random_get`
/// ZKVM | `sys_rand`
///
/// **Disclaimer:** The sources used might change over time.
///
/// [`getrandom`]: https://www.man7.org/linux/man-pages/man2/getrandom.2.html
/// [`/dev/urandom`]: https://www.man7.org/linux/man-pages/man4/random.4.html
/// [`ProcessPrng`]: https://learn.microsoft.com/en-us/windows/win32/seccng/processprng
/// [`getentropy`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/getentropy.html
/// [`esp_fill_random`]: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/random.html#_CPPv415esp_fill_randomPv6size_t
/// [`cprng_draw`]: https://fuchsia.dev/reference/syscalls/cprng_draw
/// [`kern.arandom`]: https://man.netbsd.org/rnd.4
/// [`rdrand`]: https://en.wikipedia.org/wiki/RDRAND
/// [`EFI_RNG_PROTOCOL`]: https://uefi.org/specs/UEFI/2.10/37_Secure_Technologies.html#random-number-generator-protocol
#[derive(Default, Debug, Clone, Copy)]
#[unstable(feature = "random", issue = "none")]
pub struct DefaultRandomSource;
#[unstable(feature = "random", issue = "none")]
impl RandomSource for DefaultRandomSource {
fn fill_bytes(&mut self, bytes: &mut [u8]) {
sys::fill_bytes(bytes)
}
}
/// Generates a random value with the default random source.
///
/// This is a convenience function for `T::random(&mut DefaultRandomSource)` and
/// will sample according to the same distribution as the underlying [`Random`]
/// trait implementation.
///
/// **Warning:** Be careful when manipulating random values! The
/// [`random`](Random::random) method on integers samples them with a uniform
/// distribution, so a value of 1 is just as likely as [`i32::MAX`]. By using
/// modulo operations, some of the resulting values can become more likely than
/// others. Use audited crates when in doubt.
///
/// # Examples
///
/// Generating a [version 4/variant 1 UUID] represented as text:
/// ```
/// #![feature(random)]
///
/// use std::random::random;
///
/// let bits = random::<u128>();
/// let g1 = (bits >> 96) as u32;
/// let g2 = (bits >> 80) as u16;
/// let g3 = (0x4000 | (bits >> 64) & 0x0fff) as u16;
/// let g4 = (0x8000 | (bits >> 48) & 0x3fff) as u16;
/// let g5 = (bits & 0xffffffffffff) as u64;
/// let uuid = format!("{g1:08x}-{g2:04x}-{g3:04x}-{g4:04x}-{g5:012x}");
/// println!("{uuid}");
/// ```
///
/// [version 4/variant 1 UUID]: https://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_(random)
pub fn random<T: Random>() -> T {
T::random(&mut DefaultRandomSource)
}

1
library/std/src/sys/mod.rs
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@ -15,6 +15,7 @@
pub mod exit_guard;
pub mod os_str;
pub mod path;
pub mod random;
pub mod sync;
pub mod thread_local;

14
library/std/src/sys/pal/hermit/mod.rs
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@ -52,20 +52,6 @@ pub fn abort_internal() -> ! {
unsafe { hermit_abi::abort() }
}
pub fn hashmap_random_keys() -> (u64, u64) {
let mut buf = [0; 16];
let mut slice = &mut buf[..];
while !slice.is_empty() {
let res = cvt(unsafe { hermit_abi::read_entropy(slice.as_mut_ptr(), slice.len(), 0) })
.expect("failed to generate random hashmap keys");
slice = &mut slice[res as usize..];
}
let key1 = buf[..8].try_into().unwrap();
let key2 = buf[8..].try_into().unwrap();
(u64::from_ne_bytes(key1), u64::from_ne_bytes(key2))
}
// This function is needed by the panic runtime. The symbol is named in
// pre-link args for the target specification, so keep that in sync.
#[cfg(not(test))]

4
library/std/src/sys/pal/sgx/abi/usercalls/mod.rs
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@ -1,6 +1,6 @@
use crate::cmp;
use crate::io::{Error as IoError, ErrorKind, IoSlice, IoSliceMut, Result as IoResult};
use crate::sys::rand::rdrand64;
use crate::random::{DefaultRandomSource, Random};
use crate::time::{Duration, Instant};
pub(crate) mod alloc;
@ -164,7 +164,7 @@ pub fn wait(event_mask: u64, mut timeout: u64) -> IoResult<u64> {
// trusted to ensure accurate timeouts.
if let Ok(timeout_signed) = i64::try_from(timeout) {
let tenth = timeout_signed / 10;
let deviation = (rdrand64() as i64).checked_rem(tenth).unwrap_or(0);
let deviation = i64::random(&mut DefaultRandomSource).checked_rem(tenth).unwrap_or(0);
timeout = timeout_signed.saturating_add(deviation) as _;
}
}

18
library/std/src/sys/pal/sgx/mod.rs
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@ -132,24 +132,6 @@ pub extern "C" fn __rust_abort() {
abort_internal();
}
pub mod rand {
pub fn rdrand64() -> u64 {
unsafe {
let mut ret: u64 = 0;
for _ in 0..10 {
if crate::arch::x86_64::_rdrand64_step(&mut ret) == 1 {
return ret;
}
}
rtabort!("Failed to obtain random data");
}
}
}
pub fn hashmap_random_keys() -> (u64, u64) {
(self::rand::rdrand64(), self::rand::rdrand64())
}
pub use crate::sys_common::{AsInner, FromInner, IntoInner};
pub trait TryIntoInner<Inner>: Sized {

10
library/std/src/sys/pal/solid/mod.rs
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@ -62,13 +62,3 @@ pub fn decode_error_kind(code: i32) -> crate::io::ErrorKind {
pub fn abort_internal() -> ! {
unsafe { libc::abort() }
}
pub fn hashmap_random_keys() -> (u64, u64) {
unsafe {
let mut out = crate::mem::MaybeUninit::<[u64; 2]>::uninit();
let result = abi::SOLID_RNG_SampleRandomBytes(out.as_mut_ptr() as *mut u8, 16);
assert_eq!(result, 0, "SOLID_RNG_SampleRandomBytes failed: {result}");
let [x1, x2] = out.assume_init();
(x1, x2)
}
}

3
library/std/src/sys/pal/teeos/mod.rs
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@ -6,8 +6,6 @@
#![allow(unused_variables)]
#![allow(dead_code)]
pub use self::rand::hashmap_random_keys;
#[path = "../unsupported/args.rs"]
pub mod args;
#[path = "../unsupported/env.rs"]
@ -23,7 +21,6 @@
pub mod pipe;
#[path = "../unsupported/process.rs"]
pub mod process;
mod rand;
pub mod stdio;
pub mod thread;
#[allow(non_upper_case_globals)]

21
library/std/src/sys/pal/teeos/rand.rs
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@ -1,21 +0,0 @@
pub fn hashmap_random_keys() -> (u64, u64) {
const KEY_LEN: usize = core::mem::size_of::<u64>();
let mut v = [0u8; KEY_LEN * 2];
imp::fill_bytes(&mut v);
let key1 = v[0..KEY_LEN].try_into().unwrap();
let key2 = v[KEY_LEN..].try_into().unwrap();
(u64::from_ne_bytes(key1), u64::from_ne_bytes(key2))
}
mod imp {
extern "C" {
fn TEE_GenerateRandom(randomBuffer: *mut core::ffi::c_void, randomBufferLen: libc::size_t);
}
pub fn fill_bytes(v: &mut [u8]) {
unsafe { TEE_GenerateRandom(v.as_mut_ptr() as _, v.len() * crate::mem::size_of::<u8>()) }
}
}

33
library/std/src/sys/pal/uefi/mod.rs
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@ -179,39 +179,6 @@ pub extern "C" fn __rust_abort() {
abort_internal();
}
#[inline]
pub fn hashmap_random_keys() -> (u64, u64) {
get_random().unwrap()
}
fn get_random() -> Option<(u64, u64)> {
use r_efi::protocols::rng;
let mut buf = [0u8; 16];
let handles = helpers::locate_handles(rng::PROTOCOL_GUID).ok()?;
for handle in handles {
if let Ok(protocol) = helpers::open_protocol::<rng::Protocol>(handle, rng::PROTOCOL_GUID) {
let r = unsafe {
((*protocol.as_ptr()).get_rng)(
protocol.as_ptr(),
crate::ptr::null_mut(),
buf.len(),
buf.as_mut_ptr(),
)
};
if r.is_error() {
continue;
} else {
return Some((
u64::from_le_bytes(buf[..8].try_into().ok()?),
u64::from_le_bytes(buf[8..].try_into().ok()?),
));
}
}
}
None
}
/// Disable access to BootServices if `EVT_SIGNAL_EXIT_BOOT_SERVICES` is signaled
extern "efiapi" fn exit_boot_service_handler(_e: r_efi::efi::Event, _ctx: *mut crate::ffi::c_void) {
uefi::env::disable_boot_services();

2
library/std/src/sys/pal/unix/mod.rs
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@ -1,6 +1,5 @@
#![allow(missing_docs, nonstandard_style)]
pub use self::rand::hashmap_random_keys;
use crate::io::ErrorKind;
#[cfg(not(target_os = "espidf"))]
@ -26,7 +25,6 @@
pub mod os;
pub mod pipe;
pub mod process;
pub mod rand;
pub mod stack_overflow;
pub mod stdio;
pub mod thread;

302
library/std/src/sys/pal/unix/rand.rs
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@ -1,302 +0,0 @@
pub fn hashmap_random_keys() -> (u64, u64) {
const KEY_LEN: usize = core::mem::size_of::<u64>();
let mut v = [0u8; KEY_LEN * 2];
if let Err(err) = read(&mut v) {
panic!("failed to retrieve random hash map seed: {err}");
}
let key1 = v[0..KEY_LEN].try_into().unwrap();
let key2 = v[KEY_LEN..].try_into().unwrap();
(u64::from_ne_bytes(key1), u64::from_ne_bytes(key2))
}
cfg_if::cfg_if! {
if #[cfg(any(
target_vendor = "apple",
target_os = "openbsd",
target_os = "emscripten",
target_os = "vita",
all(target_os = "netbsd", not(netbsd10)),
target_os = "fuchsia",
target_os = "vxworks",
))] {
// Some systems have a syscall that directly retrieves random data.
// If that is guaranteed to be available, use it.
use imp::syscall as read;
} else {
// Otherwise, try the syscall to see if it exists only on some systems
// and fall back to reading from the random device otherwise.
fn read(bytes: &mut [u8]) -> crate::io::Result<()> {
use crate::fs::File;
use crate::io::Read;
use crate::sync::OnceLock;
#[cfg(any(
target_os = "linux",
target_os = "android",
target_os = "espidf",
target_os = "horizon",
target_os = "freebsd",
target_os = "dragonfly",
target_os = "solaris",
target_os = "illumos",
netbsd10,
))]
if let Some(res) = imp::syscall(bytes) {
return res;
}
const PATH: &'static str = if cfg!(target_os = "redox") {
"/scheme/rand"
} else {
"/dev/urandom"
};
static FILE: OnceLock<File> = OnceLock::new();
FILE.get_or_try_init(|| File::open(PATH))?.read_exact(bytes)
}
}
}
// All these systems a `getrandom` syscall.
//
// It is not guaranteed to be available, so return None to fallback to the file
// implementation.
#[cfg(any(
target_os = "linux",
target_os = "android",
target_os = "espidf",
target_os = "horizon",
target_os = "freebsd",
target_os = "dragonfly",
target_os = "solaris",
target_os = "illumos",
netbsd10,
))]
mod imp {
use crate::io::{Error, Result};
use crate::sync::atomic::{AtomicBool, Ordering};
use crate::sys::os::errno;
#[cfg(any(target_os = "linux", target_os = "android"))]
fn getrandom(buf: &mut [u8]) -> libc::ssize_t {
use crate::sys::weak::syscall;
// A weak symbol allows interposition, e.g. for perf measurements that want to
// disable randomness for consistency. Otherwise, we'll try a raw syscall.
// (`getrandom` was added in glibc 2.25, musl 1.1.20, android API level 28)
syscall! {
fn getrandom(
buffer: *mut libc::c_void,
length: libc::size_t,
flags: libc::c_uint
) -> libc::ssize_t
}
// This provides the best quality random numbers available at the given moment
// without ever blocking, and is preferable to falling back to /dev/urandom.
static GRND_INSECURE_AVAILABLE: AtomicBool = AtomicBool::new(true);
if GRND_INSECURE_AVAILABLE.load(Ordering::Relaxed) {
let ret = unsafe { getrandom(buf.as_mut_ptr().cast(), buf.len(), libc::GRND_INSECURE) };
if ret == -1 && errno() as libc::c_int == libc::EINVAL {
GRND_INSECURE_AVAILABLE.store(false, Ordering::Relaxed);
} else {
return ret;
}
}
unsafe { getrandom(buf.as_mut_ptr().cast(), buf.len(), libc::GRND_NONBLOCK) }
}
#[cfg(any(
target_os = "dragonfly",
target_os = "espidf",
target_os = "horizon",
target_os = "freebsd",
netbsd10,
target_os = "illumos",
target_os = "solaris"
))]
fn getrandom(buf: &mut [u8]) -> libc::ssize_t {
unsafe { libc::getrandom(buf.as_mut_ptr().cast(), buf.len(), 0) }
}
pub fn syscall(v: &mut [u8]) -> Option<Result<()>> {
static GETRANDOM_UNAVAILABLE: AtomicBool = AtomicBool::new(false);
if GETRANDOM_UNAVAILABLE.load(Ordering::Relaxed) {
return None;
}
let mut read = 0;
while read < v.len() {
let result = getrandom(&mut v[read..]);
if result == -1 {
let err = errno() as libc::c_int;
if err == libc::EINTR {
continue;
} else if err == libc::ENOSYS || err == libc::EPERM {
// `getrandom` is not supported on the current system.
//
// Also fall back in case it is disabled by something like
// seccomp or inside of docker.
//
// If the `getrandom` syscall is not implemented in the current kernel version it should return an
// `ENOSYS` error. Docker also blocks the whole syscall inside unprivileged containers, and
// returns `EPERM` (instead of `ENOSYS`) when a program tries to invoke the syscall. Because of
// that we need to check for *both* `ENOSYS` and `EPERM`.
//
// Note that Docker's behavior is breaking other projects (notably glibc), so they're planning
// to update their filtering to return `ENOSYS` in a future release:
//
// https://github.com/moby/moby/issues/42680
//
GETRANDOM_UNAVAILABLE.store(true, Ordering::Relaxed);
return None;
} else if err == libc::EAGAIN {
// getrandom has failed because it would have blocked as the
// non-blocking pool (urandom) has not been initialized in
// the kernel yet due to a lack of entropy. Fallback to
// reading from `/dev/urandom` which will return potentially
// insecure random data to avoid blocking applications which
// could depend on this call without ever knowing they do and
// don't have a work around.
return None;
} else {
return Some(Err(Error::from_raw_os_error(err)));
}
} else {
read += result as usize;
}
}
Some(Ok(()))
}
}
#[cfg(any(
target_os = "macos", // Supported since macOS 10.12+.
target_os = "openbsd",
target_os = "emscripten",
target_os = "vita",
))]
mod imp {
use crate::io::{Error, Result};
pub fn syscall(v: &mut [u8]) -> Result<()> {
// getentropy(2) permits a maximum buffer size of 256 bytes
for s in v.chunks_mut(256) {
let ret = unsafe { libc::getentropy(s.as_mut_ptr().cast(), s.len()) };
if ret == -1 {
return Err(Error::last_os_error());
}
}
Ok(())
}
}
// On Apple platforms, `CCRandomGenerateBytes` and `SecRandomCopyBytes` simply
// call into `CCRandomCopyBytes` with `kCCRandomDefault`. `CCRandomCopyBytes`
// manages a CSPRNG which is seeded from the kernel's CSPRNG and which runs on
// its own thread accessed via GCD. This seems needlessly heavyweight for our purposes
// so we only use it when `getentropy` is blocked, which appears to be the case
// on all platforms except macOS (see #102643).
//
// `CCRandomGenerateBytes` is used instead of `SecRandomCopyBytes` because the former is accessible
// via `libSystem` (libc) while the other needs to link to `Security.framework`.
#[cfg(all(target_vendor = "apple", not(target_os = "macos")))]
mod imp {
use libc::size_t;
use crate::ffi::{c_int, c_void};
use crate::io::{Error, Result};
pub fn syscall(v: &mut [u8]) -> Result<()> {
extern "C" {
fn CCRandomGenerateBytes(bytes: *mut c_void, count: size_t) -> c_int;
}
let ret = unsafe { CCRandomGenerateBytes(v.as_mut_ptr().cast(), v.len()) };
if ret != -1 { Ok(()) } else { Err(Error::last_os_error()) }
}
}
// FIXME: once the 10.x release becomes the minimum, this can be dropped for simplification.
#[cfg(all(target_os = "netbsd", not(netbsd10)))]
mod imp {
use crate::io::{Error, Result};
use crate::ptr;
pub fn syscall(v: &mut [u8]) -> Result<()> {
let mib = [libc::CTL_KERN, libc::KERN_ARND];
// kern.arandom permits a maximum buffer size of 256 bytes
for s in v.chunks_mut(256) {
let mut s_len = s.len();
let ret = unsafe {
libc::sysctl(
mib.as_ptr(),
mib.len() as libc::c_uint,
s.as_mut_ptr() as *mut _,
&mut s_len,
ptr::null(),
0,
)
};
if ret == -1 {
return Err(Error::last_os_error());
} else if s_len != s.len() {
// FIXME(joboet): this can't actually happen, can it?
panic!("read less bytes than requested from kern.arandom");
}
}
Ok(())
}
}
#[cfg(target_os = "fuchsia")]
mod imp {
use crate::io::Result;
#[link(name = "zircon")]
extern "C" {
fn zx_cprng_draw(buffer: *mut u8, len: usize);
}
pub fn syscall(v: &mut [u8]) -> Result<()> {
unsafe { zx_cprng_draw(v.as_mut_ptr(), v.len()) };
Ok(())
}
}
#[cfg(target_os = "vxworks")]
mod imp {
use core::sync::atomic::AtomicBool;
use core::sync::atomic::Ordering::Relaxed;
use crate::io::{Error, Result};
pub fn syscall(v: &mut [u8]) -> Result<()> {
static RNG_INIT: AtomicBool = AtomicBool::new(false);
while !RNG_INIT.load(Relaxed) {
let ret = unsafe { libc::randSecure() };
if ret < 0 {
return Err(Error::last_os_error());
} else if ret > 0 {
RNG_INIT.store(true, Relaxed);
break;
}
unsafe { libc::usleep(10) };
}
let ret = unsafe {
libc::randABytes(v.as_mut_ptr() as *mut libc::c_uchar, v.len() as libc::c_int)
};
if ret >= 0 { Ok(()) } else { Err(Error::last_os_error()) }
}
}

4
library/std/src/sys/pal/unsupported/common.rs
View File

@ -27,7 +27,3 @@ pub fn decode_error_kind(_code: i32) -> crate::io::ErrorKind {
pub fn abort_internal() -> ! {
core::intrinsics::abort();
}
pub fn hashmap_random_keys() -> (u64, u64) {
(1, 2)
}

12
library/std/src/sys/pal/wasi/helpers.rs
View File

@ -1,6 +1,6 @@
#![forbid(unsafe_op_in_unsafe_fn)]
use crate::{io as std_io, mem};
use crate::io as std_io;
#[inline]
pub fn is_interrupted(errno: i32) -> bool {
@ -108,16 +108,6 @@ pub fn abort_internal() -> ! {
unsafe { libc::abort() }
}
pub fn hashmap_random_keys() -> (u64, u64) {
let mut ret = (0u64, 0u64);
unsafe {
let base = &mut ret as *mut (u64, u64) as *mut u8;
let len = mem::size_of_val(&ret);
wasi::random_get(base, len).expect("random_get failure");
}
ret
}
#[inline]
pub(crate) fn err2io(err: wasi::Errno) -> std_io::Error {
std_io::Error::from_raw_os_error(err.raw().into())

2
library/std/src/sys/pal/wasi/mod.rs
View File

@ -47,4 +47,4 @@
// then the compiler complains about conflicts.
use helpers::err2io;
pub use helpers::{abort_internal, decode_error_kind, hashmap_random_keys, is_interrupted};
pub use helpers::{abort_internal, decode_error_kind, is_interrupted};

2
library/std/src/sys/pal/wasip2/mod.rs
View File

@ -50,6 +50,6 @@
// then the compiler complains about conflicts.
use helpers::err2io;
pub use helpers::{abort_internal, decode_error_kind, hashmap_random_keys, is_interrupted};
pub use helpers::{abort_internal, decode_error_kind, is_interrupted};
mod cabi_realloc;

2
library/std/src/sys/pal/windows/mod.rs
View File

@ -1,7 +1,6 @@
#![allow(missing_docs, nonstandard_style)]
#![forbid(unsafe_op_in_unsafe_fn)]
pub use self::rand::hashmap_random_keys;
use crate::ffi::{OsStr, OsString};
use crate::io::ErrorKind;
use crate::mem::MaybeUninit;
@ -27,7 +26,6 @@
pub mod os;
pub mod pipe;
pub mod process;
pub mod rand;
pub mod stdio;
pub mod thread;
pub mod time;

7
library/std/src/sys/pal/windows/pipe.rs
View File

@ -2,12 +2,13 @@
use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut};
use crate::os::windows::prelude::*;
use crate::path::Path;
use crate::random::{DefaultRandomSource, Random};
use crate::sync::atomic::AtomicUsize;
use crate::sync::atomic::Ordering::Relaxed;
use crate::sys::c;
use crate::sys::fs::{File, OpenOptions};
use crate::sys::handle::Handle;
use crate::sys::pal::windows::api::{self, WinError};
use crate::sys::{c, hashmap_random_keys};
use crate::sys_common::{FromInner, IntoInner};
use crate::{mem, ptr};
@ -79,7 +80,7 @@ pub fn anon_pipe(ours_readable: bool, their_handle_inheritable: bool) -> io::Res
name = format!(
r"\\.\pipe\__rust_anonymous_pipe1__.{}.{}",
c::GetCurrentProcessId(),
random_number()
random_number(),
);
let wide_name = OsStr::new(&name).encode_wide().chain(Some(0)).collect::<Vec<_>>();
let mut flags = c::FILE_FLAG_FIRST_PIPE_INSTANCE | c::FILE_FLAG_OVERLAPPED;
@ -214,7 +215,7 @@ fn random_number() -> usize {
return N.fetch_add(1, Relaxed);
}
N.store(hashmap_random_keys().0 as usize, Relaxed);
N.store(usize::random(&mut DefaultRandomSource), Relaxed);
}
}

27
library/std/src/sys/pal/windows/rand.rs
View File

@ -1,27 +0,0 @@
use core::{mem, ptr};
use crate::sys::c;
#[cfg(not(target_vendor = "win7"))]
#[inline]
pub fn hashmap_random_keys() -> (u64, u64) {
let mut v = (0, 0);
let ret = unsafe { c::ProcessPrng(ptr::addr_of_mut!(v).cast::<u8>(), mem::size_of_val(&v)) };
// ProcessPrng is documented as always returning `TRUE`.
// https://learn.microsoft.com/en-us/windows/win32/seccng/processprng#return-value
debug_assert_eq!(ret, c::TRUE);
v
}
#[cfg(target_vendor = "win7")]
pub fn hashmap_random_keys() -> (u64, u64) {
use crate::ffi::c_void;
use crate::io;
let mut v = (0, 0);
let ret = unsafe {
c::RtlGenRandom(ptr::addr_of_mut!(v).cast::<c_void>(), mem::size_of_val(&v) as u32)
};
if ret != 0 { v } else { panic!("RNG broken: {}", io::Error::last_os_error()) }
}

8
library/std/src/sys/pal/zkvm/mod.rs
View File

@ -60,11 +60,3 @@ pub fn decode_error_kind(_code: i32) -> crate::io::ErrorKind {
pub fn abort_internal() -> ! {
core::intrinsics::abort();
}
pub fn hashmap_random_keys() -> (u64, u64) {
let mut buf = [0u32; 4];
unsafe {
abi::sys_rand(buf.as_mut_ptr(), 4);
};
((buf[0] as u64) << 32 + buf[1] as u64, (buf[2] as u64) << 32 + buf[3] as u64)
}

22
library/std/src/sys/random/apple.rs Normal file
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@ -0,0 +1,22 @@
//! Random data on non-macOS Apple platforms.
//!
//! Apple recommends the usage of `getentropy` in their security documentation[^1]
//! and mark it as being available in iOS 10.0, but we cannot use it on non-macOS
//! platforms as Apple in their *infinite wisdom* decided to consider this API
//! private, meaning its use will lead to App Store rejections (see #102643).
//!
//! Thus, we need to do the next best thing:
//!
//! Both `CCRandomGenerateBytes` and `SecRandomCopyBytes` simply call into
//! `CCRandomCopyBytes` with `kCCRandomDefault`. `CCRandomCopyBytes` manages a
//! CSPRNG which is seeded from the kernel's CSPRNG and which runs on its own
//! thread accessed via GCD (this is so wasteful...). Both are available on
//! iOS, but we use `CCRandomGenerateBytes` because it is accessible via
//! `libSystem` (libc) while the other needs to link to `Security.framework`.
//!
//! [^1]: <https://support.apple.com/en-gb/guide/security/seca0c73a75b/web>
pub fn fill_bytes(bytes: &mut [u8]) {
let ret = unsafe { libc::CCRandomGenerateBytes(bytes.as_mut_ptr().cast(), bytes.len()) };
assert_eq!(ret, libc::kCCSuccess, "failed to generate random data");
}

9
library/std/src/sys/random/espidf.rs Normal file
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@ -0,0 +1,9 @@
use crate::ffi::c_void;
extern "C" {
fn esp_fill_random(buf: *mut c_void, len: usize);
}
pub fn fill_bytes(bytes: &mut [u8]) {
unsafe { esp_fill_random(bytes.as_mut_ptr().cast(), bytes.len()) }
}

13
library/std/src/sys/random/fuchsia.rs Normal file
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@ -0,0 +1,13 @@
//! Random data generation using the Zircon kernel.
//!
//! Fuchsia, as always, is quite nice and provides exactly the API we need:
//! <https://fuchsia.dev/reference/syscalls/cprng_draw>.
#[link(name = "zircon")]
extern "C" {
fn zx_cprng_draw(buffer: *mut u8, len: usize);
}
pub fn fill_bytes(bytes: &mut [u8]) {
unsafe { zx_cprng_draw(bytes.as_mut_ptr(), bytes.len()) }
}

7
library/std/src/sys/random/hermit.rs Normal file
View File

@ -0,0 +1,7 @@
pub fn fill_bytes(mut bytes: &mut [u8]) {
while !bytes.is_empty() {
let res = unsafe { hermit_abi::read_entropy(bytes.as_mut_ptr(), bytes.len(), 0) };
assert_ne!(res, -1, "failed to generate random data");
bytes = &mut bytes[res as usize..];
}
}

7
library/std/src/sys/random/horizon.rs Normal file
View File

@ -0,0 +1,7 @@
pub fn fill_bytes(mut bytes: &mut [u8]) {
while !bytes.is_empty() {
let r = unsafe { libc::getrandom(bytes.as_mut_ptr().cast(), bytes.len(), 0) };
assert_ne!(r, -1, "failed to generate random data");
bytes = &mut bytes[r as usize..];
}
}

170
library/std/src/sys/random/linux.rs Normal file
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@ -0,0 +1,170 @@
//! Random data generation with the Linux kernel.
//!
//! The first interface random data interface to be introduced on Linux were
//! the `/dev/random` and `/dev/urandom` special files. As paths can become
//! unreachable when inside a chroot and when the file descriptors are exhausted,
//! this was not enough to provide userspace with a reliable source of randomness,
//! so when the OpenBSD 5.6 introduced the `getentropy` syscall, Linux 3.17 got
//! its very own `getrandom` syscall to match.[^1] Unfortunately, even if our
//! minimum supported version were high enough, we still couldn't rely on the
//! syscall being available, as it is blocked in `seccomp` by default.
//!
//! The question is therefore which of the random sources to use. Historically,
//! the kernel contained two pools: the blocking and non-blocking pool. The
//! blocking pool used entropy estimation to limit the amount of available
//! bytes, while the non-blocking pool, once initialized using the blocking
//! pool, uses a CPRNG to return an unlimited number of random bytes. With a
//! strong enough CPRNG however, the entropy estimation didn't contribute that
//! much towards security while being an excellent vector for DoS attacs. Thus,
//! the blocking pool was removed in kernel version 5.6.[^2] That patch did not
//! magically increase the quality of the non-blocking pool, however, so we can
//! safely consider it strong enough even in older kernel versions and use it
//! unconditionally.
//!
//! One additional consideration to make is that the non-blocking pool is not
//! always initialized during early boot. We want the best quality of randomness
//! for the output of `DefaultRandomSource` so we simply wait until it is
//! initialized. When `HashMap` keys however, this represents a potential source
//! of deadlocks, as the additional entropy may only be generated once the
//! program makes forward progress. In that case, we just use the best random
//! data the system has available at the time.
//!
//! So in conclusion, we always want the output of the non-blocking pool, but
//! may need to wait until it is initalized. The default behaviour of `getrandom`
//! is to wait until the non-blocking pool is initialized and then draw from there,
//! so if `getrandom` is available, we use its default to generate the bytes. For
//! `HashMap`, however, we need to specify the `GRND_INSECURE` flags, but that
//! is only available starting with kernel version 5.6. Thus, if we detect that
//! the flag is unsupported, we try `GRND_NONBLOCK` instead, which will only
//! succeed if the pool is initialized. If it isn't, we fall back to the file
//! access method.
//!
//! The behaviour of `/dev/urandom` is inverse to that of `getrandom`: it always
//! yields data, even when the pool is not initialized. For generating `HashMap`
//! keys, this is not important, so we can use it directly. For secure data
//! however, we need to wait until initialization, which we can do by `poll`ing
//! `/dev/random`.
//!
//! TLDR: our fallback strategies are:
//!
//! Secure data | `HashMap` keys
//! --------------------------------------------|------------------
//! getrandom(0) | getrandom(GRND_INSECURE)
//! poll("/dev/random") && read("/dev/urandom") | getrandom(GRND_NONBLOCK)
//! | read("/dev/urandom")
//!
//! [^1]: <https://lwn.net/Articles/606141/>
//! [^2]: <https://lwn.net/Articles/808575/>
//!
// FIXME(in 2040 or so): once the minimum kernel version is 5.6, remove the
// `GRND_NONBLOCK` fallback and use `/dev/random` instead of `/dev/urandom`
// when secure data is required.
use crate::fs::File;
use crate::io::Read;
use crate::os::fd::AsRawFd;
use crate::sync::atomic::AtomicBool;
use crate::sync::atomic::Ordering::{Acquire, Relaxed, Release};
use crate::sync::OnceLock;
use crate::sys::pal::os::errno;
use crate::sys::pal::weak::syscall;
fn getrandom(mut bytes: &mut [u8], insecure: bool) {
// A weak symbol allows interposition, e.g. for perf measurements that want to
// disable randomness for consistency. Otherwise, we'll try a raw syscall.
// (`getrandom` was added in glibc 2.25, musl 1.1.20, android API level 28)
syscall! {
fn getrandom(
buffer: *mut libc::c_void,
length: libc::size_t,
flags: libc::c_uint
) -> libc::ssize_t
}
static GETRANDOM_AVAILABLE: AtomicBool = AtomicBool::new(true);
static GRND_INSECURE_AVAILABLE: AtomicBool = AtomicBool::new(true);
static URANDOM_READY: AtomicBool = AtomicBool::new(false);
static DEVICE: OnceLock<File> = OnceLock::new();
if GETRANDOM_AVAILABLE.load(Relaxed) {
loop {
if bytes.is_empty() {
return;
}
let flags = if insecure {
if GRND_INSECURE_AVAILABLE.load(Relaxed) {
libc::GRND_INSECURE
} else {
libc::GRND_NONBLOCK
}
} else {
0
};
let ret = unsafe { getrandom(bytes.as_mut_ptr().cast(), bytes.len(), flags) };
if ret != -1 {
bytes = &mut bytes[ret as usize..];
} else {
match errno() {
libc::EINTR => continue,
// `GRND_INSECURE` is not available, try
// `GRND_NONBLOCK`.
libc::EINVAL if flags == libc::GRND_INSECURE => {
GRND_INSECURE_AVAILABLE.store(false, Relaxed);
continue;
}
// The pool is not initialized yet, fall back to
// /dev/urandom for now.
libc::EAGAIN if flags == libc::GRND_NONBLOCK => break,
// `getrandom` is unavailable or blocked by seccomp.
// Don't try it again and fall back to /dev/urandom.
libc::ENOSYS | libc::EPERM => {
GETRANDOM_AVAILABLE.store(false, Relaxed);
break;
}
_ => panic!("failed to generate random data"),
}
}
}
}
// When we want cryptographic strength, we need to wait for the CPRNG-pool
// to become initialized. Do this by polling `/dev/random` until it is ready.
if !insecure {
if !URANDOM_READY.load(Acquire) {
let random = File::open("/dev/random").expect("failed to open /dev/random");
let mut fd = libc::pollfd { fd: random.as_raw_fd(), events: libc::POLLIN, revents: 0 };
while !URANDOM_READY.load(Acquire) {
let ret = unsafe { libc::poll(&mut fd, 1, -1) };
match ret {
1 => {
assert_eq!(fd.revents, libc::POLLIN);
URANDOM_READY.store(true, Release);
break;
}
-1 if errno() == libc::EINTR => continue,
_ => panic!("poll(\"/dev/random\") failed"),
}
}
}
}
DEVICE
.get_or_try_init(|| File::open("/dev/urandom"))
.and_then(|mut dev| dev.read_exact(bytes))
.expect("failed to generate random data");
}
pub fn fill_bytes(bytes: &mut [u8]) {
getrandom(bytes, false);
}
pub fn hashmap_random_keys() -> (u64, u64) {
let mut bytes = [0; 16];
getrandom(&mut bytes, true);
let k1 = u64::from_ne_bytes(bytes[..8].try_into().unwrap());
let k2 = u64::from_ne_bytes(bytes[8..].try_into().unwrap());
(k1, k2)
}

98
library/std/src/sys/random/mod.rs Normal file
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@ -0,0 +1,98 @@
cfg_if::cfg_if! {
// Tier 1
if #[cfg(any(target_os = "linux", target_os = "android"))] {
mod linux;
pub use linux::{fill_bytes, hashmap_random_keys};
} else if #[cfg(target_os = "windows")] {
mod windows;
pub use windows::fill_bytes;
} else if #[cfg(any(
target_os = "openbsd",
target_os = "freebsd",
target_os = "macos",
all(target_os = "netbsd", netbsd10),
target_os = "dragonfly",
target_os = "illumos",
target_os = "solaris",
target_os = "emscripten",
target_os = "vita",
target_os = "haiku",
))] {
mod unix;
pub use unix::fill_bytes;
// Others, in alphabetical ordering.
} else if #[cfg(all(target_vendor = "apple", not(target_os = "macos")))] {
mod apple;
pub use apple::fill_bytes;
} else if #[cfg(target_os = "espidf")] {
mod espidf;
pub use espidf::fill_bytes;
} else if #[cfg(target_os = "fuchsia")] {
mod fuchsia;
pub use fuchsia::fill_bytes;
} else if #[cfg(target_os = "hermit")] {
mod hermit;
pub use hermit::fill_bytes;
} else if #[cfg(target_os = "horizon")] {
// FIXME: add getentropy to shim-3ds
mod horizon;
pub use horizon::fill_bytes;
} else if #[cfg(any(
target_os = "hurd",
target_os = "l4re",
target_os = "nto",
))] {
mod unix_legacy;
pub use unix_legacy::fill_bytes;
} else if #[cfg(all(target_os = "netbsd", not(netbsd10)))] {
// FIXME: remove once NetBSD 10 is the minimum
mod netbsd;
pub use netbsd::fill_bytes;
} else if #[cfg(target_os = "redox")] {
mod redox;
pub use redox::fill_bytes;
} else if #[cfg(all(target_vendor = "fortanix", target_env = "sgx"))] {
mod sgx;
pub use sgx::fill_bytes;
} else if #[cfg(target_os = "solid_asp3")] {
mod solid;
pub use solid::fill_bytes;
} else if #[cfg(target_os = "teeos")] {
mod teeos;
pub use teeos::fill_bytes;
} else if #[cfg(target_os = "uefi")] {
mod uefi;
pub use uefi::fill_bytes;
} else if #[cfg(target_os = "vxworks")] {
mod vxworks;
pub use vxworks::fill_bytes;
} else if #[cfg(target_os = "wasi")] {
mod wasi;
pub use wasi::fill_bytes;
} else if #[cfg(target_os = "zkvm")] {
mod zkvm;
pub use zkvm::fill_bytes;
} else if #[cfg(any(
all(target_family = "wasm", target_os = "unknown"),
target_os = "xous",
))] {
// FIXME: finally remove std support for wasm32-unknown-unknown
// FIXME: add random data generation to xous
mod unsupported;
pub use unsupported::{fill_bytes, hashmap_random_keys};
}
}
#[cfg(not(any(
target_os = "linux",
target_os = "android",
all(target_family = "wasm", target_os = "unknown"),
target_os = "xous",
)))]
pub fn hashmap_random_keys() -> (u64, u64) {
let mut buf = [0; 16];
fill_bytes(&mut buf);
let k1 = u64::from_ne_bytes(buf[..8].try_into().unwrap());
let k2 = u64::from_ne_bytes(buf[8..].try_into().unwrap());
(k1, k2)
}

19
library/std/src/sys/random/netbsd.rs Normal file
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@ -0,0 +1,19 @@
use crate::ptr;
pub fn fill_bytes(bytes: &mut [u8]) {
let mib = [libc::CTL_KERN, libc::KERN_ARND];
for chunk in bytes.chunks_mut(256) {
let mut len = chunk.len();
let ret = unsafe {
libc::sysctl(
mib.as_ptr(),
mib.len() as libc::c_uint,
chunk.as_mut_ptr().cast(),
&mut len,
ptr::null(),
0,
)
};
assert!(ret != -1 && len == chunk.len(), "failed to generate random data");
}
}

12
library/std/src/sys/random/redox.rs Normal file
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@ -0,0 +1,12 @@
use crate::fs::File;
use crate::io::Read;
use crate::sync::OnceLock;
static SCHEME: OnceLock<File> = OnceLock::new();
pub fn fill_bytes(bytes: &mut [u8]) {
SCHEME
.get_or_try_init(|| File::open("/scheme/rand"))
.and_then(|mut scheme| scheme.read_exact(bytes))
.expect("failed to generate random data");
}

67
library/std/src/sys/random/sgx.rs Normal file
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@ -0,0 +1,67 @@
use crate::arch::x86_64::{_rdrand16_step, _rdrand32_step, _rdrand64_step};
const RETRIES: u32 = 10;
fn fail() -> ! {
panic!("failed to generate random data");
}
fn rdrand64() -> u64 {
unsafe {
let mut ret: u64 = 0;
for _ in 0..RETRIES {
if _rdrand64_step(&mut ret) == 1 {
return ret;
}
}
fail();
}
}
fn rdrand32() -> u32 {
unsafe {
let mut ret: u32 = 0;
for _ in 0..RETRIES {
if _rdrand32_step(&mut ret) == 1 {
return ret;
}
}
fail();
}
}
fn rdrand16() -> u16 {
unsafe {
let mut ret: u16 = 0;
for _ in 0..RETRIES {
if _rdrand16_step(&mut ret) == 1 {
return ret;
}
}
fail();
}
}
pub fn fill_bytes(bytes: &mut [u8]) {
let mut chunks = bytes.array_chunks_mut();
for chunk in &mut chunks {
*chunk = rdrand64().to_ne_bytes();
}
let mut chunks = chunks.into_remainder().array_chunks_mut();
for chunk in &mut chunks {
*chunk = rdrand32().to_ne_bytes();
}
let mut chunks = chunks.into_remainder().array_chunks_mut();
for chunk in &mut chunks {
*chunk = rdrand16().to_ne_bytes();
}
if let [byte] = chunks.into_remainder() {
*byte = rdrand16() as u8;
}
}

8
library/std/src/sys/random/solid.rs Normal file
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@ -0,0 +1,8 @@
use crate::sys::pal::abi;
pub fn fill_bytes(bytes: &mut [u8]) {
unsafe {
let result = abi::SOLID_RNG_SampleRandomBytes(bytes.as_mut_ptr(), bytes.len());
assert_eq!(result, 0, "failed to generate random data");
}
}

7
library/std/src/sys/random/teeos.rs Normal file
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@ -0,0 +1,7 @@
extern "C" {
fn TEE_GenerateRandom(randomBuffer: *mut core::ffi::c_void, randomBufferLen: libc::size_t);
}
pub fn fill_bytes(bytes: &mut [u8]) {
unsafe { TEE_GenerateRandom(bytes.as_mut_ptr().cast(), bytes.len()) }
}

27
library/std/src/sys/random/uefi.rs Normal file
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@ -0,0 +1,27 @@
use r_efi::protocols::rng;
use crate::sys::pal::helpers;
pub fn fill_bytes(bytes: &mut [u8]) {
let handles =
helpers::locate_handles(rng::PROTOCOL_GUID).expect("failed to generate random data");
for handle in handles {
if let Ok(protocol) = helpers::open_protocol::<rng::Protocol>(handle, rng::PROTOCOL_GUID) {
let r = unsafe {
((*protocol.as_ptr()).get_rng)(
protocol.as_ptr(),
crate::ptr::null_mut(),
bytes.len(),
bytes.as_mut_ptr(),
)
};
if r.is_error() {
continue;
} else {
return;
}
}
}
panic!("failed to generate random data");
}

33
library/std/src/sys/random/unix.rs Normal file
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@ -0,0 +1,33 @@
//! Random data generation through `getentropy`.
//!
//! Since issue 8 (2024), the POSIX specification mandates the existence of the
//! `getentropy` function, which fills a slice of up to `GETENTROPY_MAX` bytes
//! (256 on all known platforms) with random data. Luckily, this function has
//! already been available on quite some BSDs before that, having appeared with
//! OpenBSD 5.7 and spread from there:
//!
//! platform | version | man-page
//! -----------|---------|----------
//! OpenBSD | 5.6 | <https://man.openbsd.org/getentropy.2>
//! FreeBSD | 12.0 | <https://man.freebsd.org/cgi/man.cgi?query=getentropy&manpath=FreeBSD+15.0-CURRENT>
//! macOS | 10.12 | <https://github.com/apple-oss-distributions/xnu/blob/94d3b452840153a99b38a3a9659680b2a006908e/bsd/man/man2/getentropy.2#L4>
//! NetBSD | 10.0 | <https://man.netbsd.org/getentropy.3>
//! DragonFly | 6.1 | <https://man.dragonflybsd.org/?command=getentropy&section=3>
//! Illumos | ? | <https://www.illumos.org/man/3C/getentropy>
//! Solaris | ? | <https://docs.oracle.com/cd/E88353_01/html/E37841/getentropy-2.html>
//!
//! As it is standardized we use it whereever possible, even when `getrandom` is
//! also available. NetBSD even warns that "Applications should avoid getrandom
//! and use getentropy(2) instead; getrandom may be removed from a later
//! release."[^1].
//!
//! [^1]: <https://man.netbsd.org/getrandom.2>
pub fn fill_bytes(bytes: &mut [u8]) {
// GETENTROPY_MAX isn't defined yet on most platforms, but it's mandated
// to be at least 256, so just use that as limit.
for chunk in bytes.chunks_mut(256) {
let r = unsafe { libc::getentropy(chunk.as_mut_ptr().cast(), chunk.len()) };
assert_ne!(r, -1, "failed to generate random data");
}
}

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library/std/src/sys/random/unix_legacy.rs Normal file
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//! Random data from `/dev/urandom`
//!
//! Before `getentropy` was standardized in 2024, UNIX didn't have a standardized
//! way of getting random data, so systems just followed the precedent set by
//! Linux and exposed random devices at `/dev/random` and `/dev/urandom`. Thus,
//! for the few systems that do not support `getentropy` yet, we just read from
//! the file.
use crate::fs::File;
use crate::io::Read;
use crate::sync::OnceLock;
static DEVICE: OnceLock<File> = OnceLock::new();
pub fn fill_bytes(bytes: &mut [u8]) {
DEVICE
.get_or_try_init(|| File::open("/dev/urandom"))
.and_then(|mut dev| dev.read_exact(bytes))
.expect("failed to generate random data");
}

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library/std/src/sys/random/unsupported.rs Normal file
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use crate::ptr;
pub fn fill_bytes(_: &mut [u8]) {
panic!("this target does not support random data generation");
}
pub fn hashmap_random_keys() -> (u64, u64) {
// Use allocation addresses for a bit of randomness. This isn't
// particularily secure, but there isn't really an alternative.
let stack = 0u8;
let heap = Box::new(0u8);
let k1 = ptr::from_ref(&stack).addr() as u64;
let k2 = ptr::from_ref(&*heap).addr() as u64;
(k1, k2)
}

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library/std/src/sys/random/vxworks.rs Normal file
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use crate::sync::atomic::AtomicBool;
use crate::sync::atomic::Ordering::Relaxed;
static RNG_INIT: AtomicBool = AtomicBool::new(false);
pub fn fill_bytes(mut bytes: &mut [u8]) {
while !RNG_INIT.load(Relaxed) {
let ret = unsafe { libc::randSecure() };
if ret < 0 {
panic!("failed to generate random data");
} else if ret > 0 {
RNG_INIT.store(true, Relaxed);
break;
}
unsafe { libc::usleep(10) };
}
while !bytes.is_empty() {
let len = bytes.len().try_into().unwrap_or(libc::c_int::MAX);
let ret = unsafe { libc::randABytes(bytes.as_mut_ptr(), len) };
assert!(ret >= 0, "failed to generate random data");
bytes = &mut bytes[len as usize..];
}
}

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library/std/src/sys/random/wasi.rs Normal file
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pub fn fill_bytes(bytes: &mut [u8]) {
unsafe {
wasi::random_get(bytes.as_mut_ptr(), bytes.len()).expect("failed to generate random data")
}
}

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library/std/src/sys/random/windows.rs Normal file
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use crate::sys::c;
#[cfg(not(target_vendor = "win7"))]
#[inline]
pub fn fill_bytes(bytes: &mut [u8]) {
let ret = unsafe { c::ProcessPrng(bytes.as_mut_ptr(), bytes.len()) };
// ProcessPrng is documented as always returning `TRUE`.
// https://learn.microsoft.com/en-us/windows/win32/seccng/processprng#return-value
debug_assert_eq!(ret, c::TRUE);
}
#[cfg(target_vendor = "win7")]
pub fn fill_bytes(mut bytes: &mut [u8]) {
while !bytes.is_empty() {
let len = bytes.len().try_into().unwrap_or(u32::MAX);
let ret = unsafe { c::RtlGenRandom(bytes.as_mut_ptr().cast(), len) };
assert_ne!(ret, 0, "failed to generate random data");
bytes = &mut bytes[len as usize..];
}
}

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library/std/src/sys/random/zkvm.rs Normal file
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use crate::sys::pal::abi;
pub fn fill_bytes(bytes: &mut [u8]) {
let (pre, words, post) = unsafe { bytes.align_to_mut::<u32>() };
if !words.is_empty() {
unsafe {
abi::sys_rand(words.as_mut_ptr(), words.len());
}
}
let mut buf = [0u32; 2];
let len = (pre.len() + post.len() + size_of::<u32>() - 1) / size_of::<u32>();
if len != 0 {
unsafe { abi::sys_rand(buf.as_mut_ptr(), len) };
}
let buf = buf.map(u32::to_ne_bytes);
let buf = buf.as_flattened();
pre.copy_from_slice(&buf[..pre.len()]);
post.copy_from_slice(&buf[pre.len()..pre.len() + post.len()]);
}