From 6dc685f1453934c9c274182edd3cddb6e1ceedda Mon Sep 17 00:00:00 2001 From: BlackHoleFox Date: Tue, 19 Dec 2023 15:03:45 -0600 Subject: [PATCH] Raise minimum supported Apple OS versions --- src/apple-other.rs | 21 +++++++++++++-------- src/lib.rs | 7 +++---- src/macos.rs | 34 ++++++++++++---------------------- src/use_file.rs | 5 ++--- 4 files changed, 30 insertions(+), 37 deletions(-) diff --git a/src/apple-other.rs b/src/apple-other.rs index 8f904859..9eeb513c 100644 --- a/src/apple-other.rs +++ b/src/apple-other.rs @@ -1,4 +1,4 @@ -// Copyright 2018 Developers of the Rand project. +// Copyright 2023 Developers of the Rand project. // // Licensed under the Apache License, Version 2.0 or the MIT license @@ -6,19 +6,24 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -//! Implementation for iOS +//! Implementation for iOS, tvOS, and watchOS where `getentropy` is unavailable. use crate::Error; -use core::{ffi::c_void, mem::MaybeUninit, ptr::null}; +use core::{ffi::c_void, mem::MaybeUninit}; -#[link(name = "Security", kind = "framework")] +// libsystem contains the libc of Darwin, and every binary ends up linked against it either way. This +// makes it a more lightweight choice compared to `Security.framework`. extern "C" { - fn SecRandomCopyBytes(rnd: *const c_void, count: usize, bytes: *mut u8) -> i32; + // This RNG uses a thread-local CSPRNG to provide data, which is seeded by the operating system's root CSPRNG. + // Its the best option after `getentropy` on modern Darwin-based platforms that also avoids the + // high startup costs and linking of Security.framework. + // + // While its just an implementation detail, `Security.framework` just calls into this anyway. + fn CCRandomGenerateBytes(bytes: *mut c_void, size: usize) -> i32; } pub fn getrandom_inner(dest: &mut [MaybeUninit]) -> Result<(), Error> { - // Apple's documentation guarantees kSecRandomDefault is a synonym for NULL. - let ret = unsafe { SecRandomCopyBytes(null(), dest.len(), dest.as_mut_ptr() as *mut u8) }; - // errSecSuccess (from SecBase.h) is always zero. + let ret = unsafe { CCRandomGenerateBytes(dest.as_mut_ptr() as *mut c_void, dest.len()) }; + // kCCSuccess (from CommonCryptoError.h) is always zero. if ret != 0 { Err(Error::IOS_SEC_RANDOM) } else { diff --git a/src/lib.rs b/src/lib.rs index fffa4cb2..6dea411e 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -14,8 +14,8 @@ //! | ----------------- | ------------------ | -------------- //! | Linux, Android | `*‑linux‑*` | [`getrandom`][1] system call if available, otherwise [`/dev/urandom`][2] after successfully polling `/dev/random` //! | Windows | `*‑windows‑*` | [`BCryptGenRandom`] -//! | macOS | `*‑apple‑darwin` | [`getentropy`][3] if available, otherwise [`/dev/urandom`][4] (identical to `/dev/random`) -//! | iOS, tvOS, watchOS | `*‑apple‑ios`, `*-apple-tvos`, `*-apple-watchos` | [`SecRandomCopyBytes`] +//! | macOS | `*‑apple‑darwin` | [`getentropy`][3] +//! | iOS, tvOS, watchOS | `*‑apple‑ios`, `*-apple-tvos`, `*-apple-watchos` | [`CCRandomGenerateBytes`] //! | FreeBSD | `*‑freebsd` | [`getrandom`][5] if available, otherwise [`kern.arandom`][6] //! | OpenBSD | `*‑openbsd` | [`getentropy`][7] //! | NetBSD | `*‑netbsd` | [`getrandom`][16] if available, otherwise [`kern.arandom`][8] @@ -172,7 +172,7 @@ //! [`BCryptGenRandom`]: https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom //! [`Crypto.getRandomValues`]: https://www.w3.org/TR/WebCryptoAPI/#Crypto-method-getRandomValues //! [`RDRAND`]: https://software.intel.com/en-us/articles/intel-digital-random-number-generator-drng-software-implementation-guide -//! [`SecRandomCopyBytes`]: https://developer.apple.com/documentation/security/1399291-secrandomcopybytes?language=objc +//! [`CCRandomGenerateBytes`]: https://opensource.apple.com/source/CommonCrypto/CommonCrypto-60074/include/CommonRandom.h.auto.html //! [`cprng_draw`]: https://fuchsia.dev/fuchsia-src/zircon/syscalls/cprng_draw //! [`crypto.randomFillSync`]: https://nodejs.org/api/crypto.html#cryptorandomfillsyncbuffer-offset-size //! [`esp_fill_random`]: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/random.html#_CPPv415esp_fill_randomPv6size_t @@ -243,7 +243,6 @@ cfg_if! { #[path = "apple-other.rs"] mod imp; } else if #[cfg(target_os = "macos")] { mod util_libc; - mod use_file; #[path = "macos.rs"] mod imp; } else if #[cfg(target_os = "openbsd")] { mod util_libc; diff --git a/src/macos.rs b/src/macos.rs index 312f9b27..61773247 100644 --- a/src/macos.rs +++ b/src/macos.rs @@ -1,4 +1,4 @@ -// Copyright 2019 Developers of the Rand project. +// Copyright 2023 Developers of the Rand project. // // Licensed under the Apache License, Version 2.0 or the MIT license @@ -7,30 +7,20 @@ // except according to those terms. //! Implementation for macOS -use crate::{ - use_file, - util_libc::{last_os_error, Weak}, - Error, -}; -use core::mem::{self, MaybeUninit}; +use crate::{util_libc::last_os_error, Error}; +use core::mem::MaybeUninit; -type GetEntropyFn = unsafe extern "C" fn(*mut u8, libc::size_t) -> libc::c_int; +extern "C" { + // Supported as of macOS 10.12+. + fn getentropy(buf: *mut u8, size: libc::size_t) -> libc::c_int; +} pub fn getrandom_inner(dest: &mut [MaybeUninit]) -> Result<(), Error> { - // getentropy(2) was added in 10.12, Rust supports 10.7+ - static GETENTROPY: Weak = unsafe { Weak::new("getentropy\0") }; - if let Some(fptr) = GETENTROPY.ptr() { - let func: GetEntropyFn = unsafe { mem::transmute(fptr) }; - for chunk in dest.chunks_mut(256) { - let ret = unsafe { func(chunk.as_mut_ptr() as *mut u8, chunk.len()) }; - if ret != 0 { - return Err(last_os_error()); - } + for chunk in dest.chunks_mut(256) { + let ret = unsafe { getentropy(chunk.as_mut_ptr() as *mut u8, chunk.len()) }; + if ret != 0 { + return Err(last_os_error()); } - Ok(()) - } else { - // We fallback to reading from /dev/random instead of SecRandomCopyBytes - // to avoid high startup costs and linking the Security framework. - use_file::getrandom_inner(dest) } + Ok(()) } diff --git a/src/use_file.rs b/src/use_file.rs index 23a5a5ae..273be65f 100644 --- a/src/use_file.rs +++ b/src/use_file.rs @@ -1,4 +1,4 @@ -// Copyright 2018 Developers of the Rand project. +// Copyright 2023 Developers of the Rand project. // // Licensed under the Apache License, Version 2.0 or the MIT license @@ -20,7 +20,7 @@ use core::{ // We prefer using /dev/urandom and only use /dev/random if the OS // documentation indicates that /dev/urandom is insecure. // On Solaris/Illumos, see src/solaris_illumos.rs -// On Dragonfly, Haiku, macOS, and QNX Neutrino the devices are identical. +// On Dragonfly, Haiku, and QNX Neutrino the devices are identical. #[cfg(any(target_os = "solaris", target_os = "illumos"))] const FILE_PATH: &str = "/dev/random\0"; #[cfg(any( @@ -30,7 +30,6 @@ const FILE_PATH: &str = "/dev/random\0"; target_os = "redox", target_os = "dragonfly", target_os = "haiku", - target_os = "macos", target_os = "nto", ))] const FILE_PATH: &str = "/dev/urandom\0";