diff options
Diffstat (limited to 'third_party/rust/getrandom/src/apple-other.rs')
| -rw-r--r-- | third_party/rust/getrandom/src/apple-other.rs | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/third_party/rust/getrandom/src/apple-other.rs b/third_party/rust/getrandom/src/apple-other.rs index 8f904859ca..167d8cf0fa 100644 --- a/third_party/rust/getrandom/src/apple-other.rs +++ b/third_party/rust/getrandom/src/apple-other.rs @@ -1,24 +1,21 @@ -// Copyright 2018 Developers of the Rand project. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your -// 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<u8>]) -> 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 { |