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Use arc4rand(9) on FreeBSD #35884

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Merged
merged 2 commits into from
Aug 25, 2016
Merged

Use arc4rand(9) on FreeBSD #35884

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ef6aab2
Reduce duplication in std::sys::unix::rand.
habnabit Jul 29, 2016
0a70944
Use the kernel arc4rand for FreeBSD OsRng.
habnabit Aug 14, 2016
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107 changes: 77 additions & 30 deletions src/libstd/sys/unix/rand.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,14 +10,31 @@

pub use self::imp::OsRng;

#[cfg(all(unix, not(target_os = "ios"), not(target_os = "openbsd")))]
use mem;

fn next_u32(mut fill_buf: &mut FnMut(&mut [u8])) -> u32 {
let mut buf: [u8; 4] = [0; 4];
fill_buf(&mut buf);
unsafe { mem::transmute::<[u8; 4], u32>(buf) }
}

fn next_u64(mut fill_buf: &mut FnMut(&mut [u8])) -> u64 {
let mut buf: [u8; 8] = [0; 8];
fill_buf(&mut buf);
unsafe { mem::transmute::<[u8; 8], u64>(buf) }
}
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@eddyb eddyb Aug 22, 2016

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Why are these not using a generic F: FnMut(&mut [u8])?

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@habnabit habnabit Aug 22, 2016

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No particular reason, I suppose.


#[cfg(all(unix,
not(target_os = "ios"),
not(target_os = "openbsd"),
not(target_os = "freebsd")))]
mod imp {
use self::OsRngInner::*;
use super::{next_u32, next_u64};

use fs::File;
use io;
use libc;
use mem;
use rand::Rng;
use rand::reader::ReaderRng;
use sys::os::errno;
Expand Down Expand Up @@ -87,18 +104,6 @@ mod imp {
}
}

fn getrandom_next_u32() -> u32 {
let mut buf: [u8; 4] = [0; 4];
getrandom_fill_bytes(&mut buf);
unsafe { mem::transmute::<[u8; 4], u32>(buf) }
}

fn getrandom_next_u64() -> u64 {
let mut buf: [u8; 8] = [0; 8];
getrandom_fill_bytes(&mut buf);
unsafe { mem::transmute::<[u8; 8], u64>(buf) }
}

#[cfg(all(target_os = "linux",
any(target_arch = "x86_64",
target_arch = "x86",
Expand Down Expand Up @@ -163,13 +168,13 @@ mod imp {
impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
match self.inner {
OsGetrandomRng => getrandom_next_u32(),
OsGetrandomRng => next_u32(&mut getrandom_fill_bytes),
OsReaderRng(ref mut rng) => rng.next_u32(),
}
}
fn next_u64(&mut self) -> u64 {
match self.inner {
OsGetrandomRng => getrandom_next_u64(),
OsGetrandomRng => next_u64(&mut getrandom_fill_bytes),
OsReaderRng(ref mut rng) => rng.next_u64(),
}
}
Expand All @@ -184,9 +189,10 @@ mod imp {

#[cfg(target_os = "openbsd")]
mod imp {
use super::{next_u32, next_u64};

use io;
use libc;
use mem;
use sys::os::errno;
use rand::Rng;

Expand All @@ -205,14 +211,10 @@ mod imp {

impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
let mut v = [0; 4];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
next_u32(&mut |v| self.fill_bytes(v))
}
fn next_u64(&mut self) -> u64 {
let mut v = [0; 8];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
next_u64(&mut |v| self.fill_bytes(v))
}
fn fill_bytes(&mut self, v: &mut [u8]) {
// getentropy(2) permits a maximum buffer size of 256 bytes
Expand All @@ -230,8 +232,9 @@ mod imp {

#[cfg(target_os = "ios")]
mod imp {
use super::{next_u32, next_u64};

use io;
use mem;
use ptr;
use rand::Rng;
use libc::{c_int, size_t};
Expand Down Expand Up @@ -265,14 +268,10 @@ mod imp {

impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
let mut v = [0; 4];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
next_u32(&mut |v| self.fill_bytes(v))
}
fn next_u64(&mut self) -> u64 {
let mut v = [0; 8];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
next_u64(&mut |v| self.fill_bytes(v))
}
fn fill_bytes(&mut self, v: &mut [u8]) {
let ret = unsafe {
Expand All @@ -286,3 +285,51 @@ mod imp {
}
}
}

#[cfg(target_os = "freebsd")]
mod imp {
use super::{next_u32, next_u64};

use io;
use libc;
use rand::Rng;
use ptr;

pub struct OsRng {
// dummy field to ensure that this struct cannot be constructed outside
// of this module
_dummy: (),
}

impl OsRng {
/// Create a new `OsRng`.
pub fn new() -> io::Result<OsRng> {
Ok(OsRng { _dummy: () })
}
}

impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
next_u32(&mut |v| self.fill_bytes(v))
}
fn next_u64(&mut self) -> u64 {
next_u64(&mut |v| self.fill_bytes(v))
}
fn fill_bytes(&mut self, v: &mut [u8]) {
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 || s_len != s.len() {
panic!("kern.arandom sysctl failed! (returned {}, s.len() {}, oldlenp {})",
ret, s.len(), s_len);
}
}
}
}
}