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Diffstat (limited to 'rand/src/rngs/os.rs')
| -rw-r--r-- | rand/src/rngs/os.rs | 1275 |
1 files changed, 0 insertions, 1275 deletions
diff --git a/rand/src/rngs/os.rs b/rand/src/rngs/os.rs deleted file mode 100644 index e609c50..0000000 --- a/rand/src/rngs/os.rs +++ /dev/null @@ -1,1275 +0,0 @@ -// Copyright 2018 Developers of the Rand project. -// Copyright 2013-2015 The Rust Project Developers. -// -// 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. - -//! Interface to the random number generator of the operating system. - -use std::fmt; -use rand_core::{CryptoRng, RngCore, Error, impls}; - -/// A random number generator that retrieves randomness straight from the -/// operating system. -/// -/// This is the preferred external source of entropy for most applications. -/// Commonly it is used to initialize a user-space RNG, which can then be used -/// to generate random values with much less overhead than `OsRng`. -/// -/// You may prefer to use [`EntropyRng`] instead of `OsRng`. It is unlikely, but -/// not entirely theoretical, for `OsRng` to fail. In such cases [`EntropyRng`] -/// falls back on a good alternative entropy source. -/// -/// `OsRng::new()` is guaranteed to be very cheap (after the first successful -/// call), and will never consume more than one file handle per process. -/// -/// # Platform sources -/// -/// | OS | interface -/// |------------------|--------------------------------------------------------- -/// | Linux, Android | [`getrandom`][1] system call if available, otherwise [`/dev/urandom`][2] after reading from `/dev/random` once -/// | Windows | [`RtlGenRandom`][3] -/// | macOS, iOS | [`SecRandomCopyBytes`][4] -/// | FreeBSD | [`kern.arandom`][5] -/// | OpenBSD, Bitrig | [`getentropy`][6] -/// | NetBSD | [`/dev/urandom`][7] after reading from `/dev/random` once -/// | Dragonfly BSD | [`/dev/random`][8] -/// | Solaris, illumos | [`getrandom`][9] system call if available, otherwise [`/dev/random`][10] -/// | Fuchsia OS | [`cprng_draw`][11] -/// | Redox | [`rand:`][12] -/// | CloudABI | [`random_get`][13] -/// | Haiku | `/dev/random` (identical to `/dev/urandom`) -/// | Web browsers | [`Crypto.getRandomValues`][14] (see [Support for WebAssembly and ams.js][14]) -/// | Node.js | [`crypto.randomBytes`][15] (see [Support for WebAssembly and ams.js][16]) -/// -/// Rand doesn't have a blanket implementation for all Unix-like operating -/// systems that reads from `/dev/urandom`. This ensures all supported operating -/// systems are using the recommended interface and respect maximum buffer -/// sizes. -/// -/// ## Support for WebAssembly and ams.js -/// -/// The three Emscripten targets `asmjs-unknown-emscripten`, -/// `wasm32-unknown-emscripten` and `wasm32-experimental-emscripten` use -/// Emscripten's emulation of `/dev/random` on web browsers and Node.js. -/// -/// The bare Wasm target `wasm32-unknown-unknown` tries to call the javascript -/// methods directly, using either `stdweb` in combination with `cargo-web` or -/// `wasm-bindgen` depending on what features are activated for this crate. -/// -/// ## Early boot -/// -/// It is possible that early in the boot process the OS hasn't had enough time -/// yet to collect entropy to securely seed its RNG, especially on virtual -/// machines. -/// -/// Some operating systems always block the thread until the RNG is securely -/// seeded. This can take anywhere from a few seconds to more than a minute. -/// Others make a best effort to use a seed from before the shutdown and don't -/// document much. -/// -/// A few, Linux, NetBSD and Solaris, offer a choice between blocking, and -/// getting an error. With `try_fill_bytes` we choose to get the error -/// ([`ErrorKind::NotReady`]), while the other methods use a blocking interface. -/// -/// On Linux (when the `genrandom` system call is not available) and on NetBSD -/// reading from `/dev/urandom` never blocks, even when the OS hasn't collected -/// enough entropy yet. As a countermeasure we try to do a single read from -/// `/dev/random` until we know the OS RNG is initialized (and store this in a -/// global static). -/// -/// # Panics -/// -/// `OsRng` is extremely unlikely to fail if `OsRng::new()`, and one read from -/// it, where succesfull. But in case it does fail, only [`try_fill_bytes`] is -/// able to report the cause. Depending on the error the other [`RngCore`] -/// methods will retry several times, and panic in case the error remains. -/// -/// [`EntropyRng`]: struct.EntropyRng.html -/// [`RngCore`]: ../trait.RngCore.html -/// [`try_fill_bytes`]: ../trait.RngCore.html#method.tymethod.try_fill_bytes -/// [`ErrorKind::NotReady`]: ../enum.ErrorKind.html#variant.NotReady -/// -/// [1]: http://man7.org/linux/man-pages/man2/getrandom.2.html -/// [2]: http://man7.org/linux/man-pages/man4/urandom.4.html -/// [3]: https://msdn.microsoft.com/en-us/library/windows/desktop/aa387694.aspx -/// [4]: https://developer.apple.com/documentation/security/1399291-secrandomcopybytes?language=objc -/// [5]: https://www.freebsd.org/cgi/man.cgi?query=random&sektion=4 -/// [6]: https://man.openbsd.org/getentropy.2 -/// [7]: http://netbsd.gw.com/cgi-bin/man-cgi?random+4+NetBSD-current -/// [8]: https://leaf.dragonflybsd.org/cgi/web-man?command=random§ion=4 -/// [9]: https://docs.oracle.com/cd/E88353_01/html/E37841/getrandom-2.html -/// [10]: https://docs.oracle.com/cd/E86824_01/html/E54777/random-7d.html -/// [11]: https://fuchsia.googlesource.com/zircon/+/HEAD/docs/syscalls/cprng_draw.md -/// [12]: https://github.com/redox-os/randd/blob/master/src/main.rs -/// [13]: https://github.com/NuxiNL/cloudabi/blob/v0.20/cloudabi.txt#L1826 -/// [14]: https://www.w3.org/TR/WebCryptoAPI/#Crypto-method-getRandomValues -/// [15]: https://nodejs.org/api/crypto.html#crypto_crypto_randombytes_size_callback -/// [16]: #support-for-webassembly-and-amsjs - - -#[derive(Clone)] -pub struct OsRng(imp::OsRng); - -impl fmt::Debug for OsRng { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - self.0.fmt(f) - } -} - -impl OsRng { - /// Create a new `OsRng`. - pub fn new() -> Result<OsRng, Error> { - imp::OsRng::new().map(OsRng) - } -} - -impl CryptoRng for OsRng {} - -impl RngCore for OsRng { - fn next_u32(&mut self) -> u32 { - impls::next_u32_via_fill(self) - } - - fn next_u64(&mut self) -> u64 { - impls::next_u64_via_fill(self) - } - - fn fill_bytes(&mut self, dest: &mut [u8]) { - use std::{time, thread}; - - // We cannot return Err(..), so we try to handle before panicking. - const MAX_RETRY_PERIOD: u32 = 10; // max 10s - const WAIT_DUR_MS: u32 = 100; // retry every 100ms - let wait_dur = time::Duration::from_millis(WAIT_DUR_MS as u64); - const RETRY_LIMIT: u32 = (MAX_RETRY_PERIOD * 1000) / WAIT_DUR_MS; - const TRANSIENT_RETRIES: u32 = 8; - let mut err_count = 0; - let mut error_logged = false; - - // Maybe block until the OS RNG is initialized - let mut read = 0; - if let Ok(n) = self.0.test_initialized(dest, true) { read = n }; - let dest = &mut dest[read..]; - - loop { - if let Err(e) = self.try_fill_bytes(dest) { - if err_count >= RETRY_LIMIT { - error!("OsRng failed too many times; last error: {}", e); - panic!("OsRng failed too many times; last error: {}", e); - } - - if e.kind.should_wait() { - if !error_logged { - warn!("OsRng failed; waiting up to {}s and retrying. Error: {}", - MAX_RETRY_PERIOD, e); - error_logged = true; - } - err_count += 1; - thread::sleep(wait_dur); - continue; - } else if e.kind.should_retry() { - if !error_logged { - warn!("OsRng failed; retrying up to {} times. Error: {}", - TRANSIENT_RETRIES, e); - error_logged = true; - } - err_count += (RETRY_LIMIT + TRANSIENT_RETRIES - 1) - / TRANSIENT_RETRIES; // round up - continue; - } else { - error!("OsRng failed: {}", e); - panic!("OsRng fatal error: {}", e); - } - } - - break; - } - } - - fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { - // Some systems do not support reading 0 random bytes. - // (And why waste a system call?) - if dest.len() == 0 { return Ok(()); } - - let read = self.0.test_initialized(dest, false)?; - let dest = &mut dest[read..]; - - let max = self.0.max_chunk_size(); - if dest.len() <= max { - trace!("OsRng: reading {} bytes via {}", - dest.len(), self.0.method_str()); - } else { - trace!("OsRng: reading {} bytes via {} in {} chunks of {} bytes", - dest.len(), self.0.method_str(), (dest.len() + max) / max, max); - } - for slice in dest.chunks_mut(max) { - self.0.fill_chunk(slice)?; - } - Ok(()) - } -} - -trait OsRngImpl where Self: Sized { - // Create a new `OsRng` platform interface. - fn new() -> Result<Self, Error>; - - // Fill a chunk with random bytes. - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error>; - - // Test whether the OS RNG is initialized. This method may not be possible - // to support cheaply (or at all) on all operating systems. - // - // If `blocking` is set, this will cause the OS the block execution until - // its RNG is initialized. - // - // Random values that are read while this are stored in `dest`, the amount - // of read bytes is returned. - fn test_initialized(&mut self, _dest: &mut [u8], _blocking: bool) - -> Result<usize, Error> { Ok(0) } - - // Maximum chunk size supported. - fn max_chunk_size(&self) -> usize { ::core::usize::MAX } - - // Name of the OS interface (used for logging). - fn method_str(&self) -> &'static str; -} - - - - -// Helper functions to read from a random device such as `/dev/urandom`. -// -// All instances use a single internal file handle, to prevent possible -// exhaustion of file descriptors. -#[cfg(any(target_os = "linux", target_os = "android", - target_os = "netbsd", target_os = "dragonfly", - target_os = "solaris", target_os = "redox", - target_os = "haiku", target_os = "emscripten"))] -mod random_device { - use {Error, ErrorKind}; - use std::fs::File; - use std::io; - use std::io::Read; - use std::sync::{Once, Mutex, ONCE_INIT}; - - // TODO: remove outer Option when `Mutex::new(None)` is a constant expression - static mut READ_RNG_FILE: Option<Mutex<Option<File>>> = None; - static READ_RNG_ONCE: Once = ONCE_INIT; - - #[allow(unused)] - pub fn open<F>(path: &'static str, open_fn: F) -> Result<(), Error> - where F: Fn(&'static str) -> Result<File, io::Error> - { - READ_RNG_ONCE.call_once(|| { - unsafe { READ_RNG_FILE = Some(Mutex::new(None)) } - }); - - // We try opening the file outside the `call_once` fn because we cannot - // clone the error, thus we must retry on failure. - - let mutex = unsafe { READ_RNG_FILE.as_ref().unwrap() }; - let mut guard = mutex.lock().unwrap(); - if (*guard).is_none() { - info!("OsRng: opening random device {}", path); - let file = open_fn(path).map_err(map_err)?; - *guard = Some(file); - }; - Ok(()) - } - - pub fn read(dest: &mut [u8]) -> Result<(), Error> { - // We expect this function only to be used after `random_device::open` - // was succesful. Therefore we can assume that our memory was set with a - // valid object. - let mutex = unsafe { READ_RNG_FILE.as_ref().unwrap() }; - let mut guard = mutex.lock().unwrap(); - let file = (*guard).as_mut().unwrap(); - - // Use `std::io::read_exact`, which retries on `ErrorKind::Interrupted`. - file.read_exact(dest).map_err(|err| { - Error::with_cause(ErrorKind::Unavailable, - "error reading random device", err) - }) - - } - - pub fn map_err(err: io::Error) -> Error { - match err.kind() { - io::ErrorKind::Interrupted => - Error::new(ErrorKind::Transient, "interrupted"), - io::ErrorKind::WouldBlock => - Error::with_cause(ErrorKind::NotReady, - "OS RNG not yet seeded", err), - _ => Error::with_cause(ErrorKind::Unavailable, - "error while opening random device", err) - } - } -} - - -#[cfg(any(target_os = "linux", target_os = "android"))] -mod imp { - extern crate libc; - - use {Error, ErrorKind}; - use super::random_device; - use super::OsRngImpl; - - use std::io; - use std::io::Read; - use std::fs::{File, OpenOptions}; - use std::os::unix::fs::OpenOptionsExt; - use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering}; - use std::sync::{Once, ONCE_INIT}; - - #[derive(Clone, Debug)] - pub struct OsRng { - method: OsRngMethod, - initialized: bool, - } - - #[derive(Clone, Debug)] - enum OsRngMethod { - GetRandom, - RandomDevice, - } - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { - if is_getrandom_available() { - return Ok(OsRng { method: OsRngMethod::GetRandom, - initialized: false }); - } - random_device::open("/dev/urandom", &|p| File::open(p))?; - Ok(OsRng { method: OsRngMethod::RandomDevice, initialized: false }) - } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - match self.method { - OsRngMethod::GetRandom => getrandom_try_fill(dest, false), - OsRngMethod::RandomDevice => random_device::read(dest), - } - } - - fn test_initialized(&mut self, dest: &mut [u8], blocking: bool) - -> Result<usize, Error> - { - static OS_RNG_INITIALIZED: AtomicBool = ATOMIC_BOOL_INIT; - if !self.initialized { - self.initialized = OS_RNG_INITIALIZED.load(Ordering::Relaxed); - } - if self.initialized { return Ok(0); } - - let result = match self.method { - OsRngMethod::GetRandom => { - getrandom_try_fill(dest, blocking)?; - Ok(dest.len()) - } - OsRngMethod::RandomDevice => { - info!("OsRng: testing random device /dev/random"); - let mut file = OpenOptions::new() - .read(true) - .custom_flags(if blocking { 0 } else { libc::O_NONBLOCK }) - .open("/dev/random") - .map_err(random_device::map_err)?; - file.read(&mut dest[..1]).map_err(random_device::map_err)?; - Ok(1) - } - }; - OS_RNG_INITIALIZED.store(true, Ordering::Relaxed); - self.initialized = true; - result - } - - fn method_str(&self) -> &'static str { - match self.method { - OsRngMethod::GetRandom => "getrandom", - OsRngMethod::RandomDevice => "/dev/urandom", - } - } - } - - #[cfg(target_arch = "x86_64")] - const NR_GETRANDOM: libc::c_long = 318; - #[cfg(target_arch = "x86")] - const NR_GETRANDOM: libc::c_long = 355; - #[cfg(target_arch = "arm")] - const NR_GETRANDOM: libc::c_long = 384; - #[cfg(target_arch = "aarch64")] - const NR_GETRANDOM: libc::c_long = 278; - #[cfg(target_arch = "s390x")] - const NR_GETRANDOM: libc::c_long = 349; - #[cfg(target_arch = "powerpc")] - const NR_GETRANDOM: libc::c_long = 359; - #[cfg(target_arch = "powerpc64")] - const NR_GETRANDOM: libc::c_long = 359; - #[cfg(target_arch = "mips")] // old ABI - const NR_GETRANDOM: libc::c_long = 4353; - #[cfg(target_arch = "mips64")] - const NR_GETRANDOM: libc::c_long = 5313; - #[cfg(target_arch = "sparc")] - const NR_GETRANDOM: libc::c_long = 347; - #[cfg(target_arch = "sparc64")] - const NR_GETRANDOM: libc::c_long = 347; - #[cfg(not(any(target_arch = "x86_64", target_arch = "x86", - target_arch = "arm", target_arch = "aarch64", - target_arch = "s390x", target_arch = "powerpc", - target_arch = "powerpc64", target_arch = "mips", - target_arch = "mips64", target_arch = "sparc", - target_arch = "sparc64")))] - const NR_GETRANDOM: libc::c_long = 0; - - fn getrandom(buf: &mut [u8], blocking: bool) -> libc::c_long { - const GRND_NONBLOCK: libc::c_uint = 0x0001; - - if NR_GETRANDOM == 0 { return -1 }; - - unsafe { - libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), - if blocking { 0 } else { GRND_NONBLOCK }) - } - } - - fn getrandom_try_fill(dest: &mut [u8], blocking: bool) -> Result<(), Error> { - let mut read = 0; - while read < dest.len() { - let result = getrandom(&mut dest[read..], blocking); - if result == -1 { - let err = io::Error::last_os_error(); - let kind = err.kind(); - if kind == io::ErrorKind::Interrupted { - continue; - } else if kind == io::ErrorKind::WouldBlock { - return Err(Error::with_cause( - ErrorKind::NotReady, - "getrandom not ready", - err, - )); - } else { - return Err(Error::with_cause( - ErrorKind::Unavailable, - "unexpected getrandom error", - err, - )); - } - } else { - read += result as usize; - } - } - Ok(()) - } - - fn is_getrandom_available() -> bool { - static CHECKER: Once = ONCE_INIT; - static AVAILABLE: AtomicBool = ATOMIC_BOOL_INIT; - - if NR_GETRANDOM == 0 { return false }; - - CHECKER.call_once(|| { - debug!("OsRng: testing getrandom"); - let mut buf: [u8; 0] = []; - let result = getrandom(&mut buf, false); - let available = if result == -1 { - let err = io::Error::last_os_error().raw_os_error(); - err != Some(libc::ENOSYS) - } else { - true - }; - AVAILABLE.store(available, Ordering::Relaxed); - info!("OsRng: using {}", if available { "getrandom" } else { "/dev/urandom" }); - }); - - AVAILABLE.load(Ordering::Relaxed) - } -} - - -#[cfg(target_os = "netbsd")] -mod imp { - use Error; - use super::random_device; - use super::OsRngImpl; - - use std::fs::File; - use std::io::Read; - use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering}; - - #[derive(Clone, Debug)] - pub struct OsRng { initialized: bool } - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { - random_device::open("/dev/urandom", &|p| File::open(p))?; - Ok(OsRng { initialized: false }) - } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - random_device::read(dest) - } - - // Read a single byte from `/dev/random` to determine if the OS RNG is - // already seeded. NetBSD always blocks if not yet ready. - fn test_initialized(&mut self, dest: &mut [u8], _blocking: bool) - -> Result<usize, Error> - { - static OS_RNG_INITIALIZED: AtomicBool = ATOMIC_BOOL_INIT; - if !self.initialized { - self.initialized = OS_RNG_INITIALIZED.load(Ordering::Relaxed); - } - if self.initialized { return Ok(0); } - - info!("OsRng: testing random device /dev/random"); - let mut file = - File::open("/dev/random").map_err(random_device::map_err)?; - file.read(&mut dest[..1]).map_err(random_device::map_err)?; - - OS_RNG_INITIALIZED.store(true, Ordering::Relaxed); - self.initialized = true; - Ok(1) - } - - fn method_str(&self) -> &'static str { "/dev/urandom" } - } -} - - -#[cfg(any(target_os = "dragonfly", - target_os = "haiku", - target_os = "emscripten"))] -mod imp { - use Error; - use super::random_device; - use super::OsRngImpl; - use std::fs::File; - - #[derive(Clone, Debug)] - pub struct OsRng(); - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { - random_device::open("/dev/random", &|p| File::open(p))?; - Ok(OsRng()) - } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - random_device::read(dest) - } - - #[cfg(target_os = "emscripten")] - fn max_chunk_size(&self) -> usize { - // `Crypto.getRandomValues` documents `dest` should be at most 65536 - // bytes. `crypto.randomBytes` documents: "To minimize threadpool - // task length variation, partition large randomBytes requests when - // doing so as part of fulfilling a client request. - 65536 - } - - fn method_str(&self) -> &'static str { "/dev/random" } - } -} - - -// Read from `/dev/random`, with chunks of limited size (1040 bytes). -// `/dev/random` uses the Hash_DRBG with SHA512 algorithm from NIST SP 800-90A. -// `/dev/urandom` uses the FIPS 186-2 algorithm, which is considered less -// secure. We choose to read from `/dev/random`. -// -// Since Solaris 11.3 the `getrandom` syscall is available. To make sure we can -// compile on both Solaris and on OpenSolaris derivatives, that do not have the -// function, we do a direct syscall instead of calling a library function. -// -// We have no way to differentiate between Solaris, illumos, SmartOS, etc. -#[cfg(target_os = "solaris")] -mod imp { - extern crate libc; - - use {Error, ErrorKind}; - use super::random_device; - use super::OsRngImpl; - - use std::io; - use std::io::Read; - use std::fs::{File, OpenOptions}; - use std::os::unix::fs::OpenOptionsExt; - use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering}; - - #[derive(Clone, Debug)] - pub struct OsRng { - method: OsRngMethod, - initialized: bool, - } - - #[derive(Clone, Debug)] - enum OsRngMethod { - GetRandom, - RandomDevice, - } - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { - if is_getrandom_available() { - return Ok(OsRng { method: OsRngMethod::GetRandom, - initialized: false }); - } - let open = |p| OpenOptions::new() - .read(true) - .custom_flags(libc::O_NONBLOCK) - .open(p); - random_device::open("/dev/random", &open)?; - Ok(OsRng { method: OsRngMethod::RandomDevice, initialized: false }) - } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - match self.method { - OsRngMethod::GetRandom => getrandom_try_fill(dest, false), - OsRngMethod::RandomDevice => random_device::read(dest), - } - } - - fn test_initialized(&mut self, dest: &mut [u8], blocking: bool) - -> Result<usize, Error> - { - static OS_RNG_INITIALIZED: AtomicBool = ATOMIC_BOOL_INIT; - if !self.initialized { - self.initialized = OS_RNG_INITIALIZED.load(Ordering::Relaxed); - } - if self.initialized { return Ok(0); } - - let chunk_len = ::core::cmp::min(1024, dest.len()); - let dest = &mut dest[..chunk_len]; - - match self.method { - OsRngMethod::GetRandom => getrandom_try_fill(dest, blocking)?, - OsRngMethod::RandomDevice => { - if blocking { - info!("OsRng: testing random device /dev/random"); - // We already have a non-blocking handle, but now need a - // blocking one. Not much choice except opening it twice - let mut file = File::open("/dev/random") - .map_err(random_device::map_err)?; - file.read(dest).map_err(random_device::map_err)?; - } else { - self.fill_chunk(dest)?; - } - } - }; - OS_RNG_INITIALIZED.store(true, Ordering::Relaxed); - self.initialized = true; - Ok(chunk_len) - } - - fn max_chunk_size(&self) -> usize { - // The documentation says 1024 is the maximum for getrandom, but - // 1040 for /dev/random. - 1024 - } - - fn method_str(&self) -> &'static str { - match self.method { - OsRngMethod::GetRandom => "getrandom", - OsRngMethod::RandomDevice => "/dev/random", - } - } - } - - fn getrandom(buf: &mut [u8], blocking: bool) -> libc::c_long { - extern "C" { - fn syscall(number: libc::c_long, ...) -> libc::c_long; - } - - const SYS_GETRANDOM: libc::c_long = 143; - const GRND_NONBLOCK: libc::c_uint = 0x0001; - const GRND_RANDOM: libc::c_uint = 0x0002; - - unsafe { - syscall(SYS_GETRANDOM, buf.as_mut_ptr(), buf.len(), - if blocking { 0 } else { GRND_NONBLOCK } | GRND_RANDOM) - } - } - - fn getrandom_try_fill(dest: &mut [u8], blocking: bool) -> Result<(), Error> { - let result = getrandom(dest, blocking); - if result == -1 || result == 0 { - let err = io::Error::last_os_error(); - let kind = err.kind(); - if kind == io::ErrorKind::WouldBlock { - return Err(Error::with_cause( - ErrorKind::NotReady, - "getrandom not ready", - err, - )); - } else { - return Err(Error::with_cause( - ErrorKind::Unavailable, - "unexpected getrandom error", - err, - )); - } - } else if result != dest.len() as i64 { - return Err(Error::new(ErrorKind::Unavailable, - "unexpected getrandom error")); - } - Ok(()) - } - - fn is_getrandom_available() -> bool { - use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering}; - use std::sync::{Once, ONCE_INIT}; - - static CHECKER: Once = ONCE_INIT; - static AVAILABLE: AtomicBool = ATOMIC_BOOL_INIT; - - CHECKER.call_once(|| { - debug!("OsRng: testing getrandom"); - let mut buf: [u8; 0] = []; - let result = getrandom(&mut buf, false); - let available = if result == -1 { - let err = io::Error::last_os_error().raw_os_error(); - err != Some(libc::ENOSYS) - } else { - true - }; - AVAILABLE.store(available, Ordering::Relaxed); - info!("OsRng: using {}", if available { "getrandom" } else { "/dev/random" }); - }); - - AVAILABLE.load(Ordering::Relaxed) - } -} - - -#[cfg(target_os = "cloudabi")] -mod imp { - extern crate cloudabi; - - use std::io; - use {Error, ErrorKind}; - use super::OsRngImpl; - - #[derive(Clone, Debug)] - pub struct OsRng; - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { Ok(OsRng) } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - let errno = unsafe { cloudabi::random_get(dest) }; - if errno == cloudabi::errno::SUCCESS { - Ok(()) - } else { - // Cloudlibc provides its own `strerror` implementation so we - // can use `from_raw_os_error` here. - Err(Error::with_cause( - ErrorKind::Unavailable, - "random_get() system call failed", - io::Error::from_raw_os_error(errno as i32), - )) - } - } - - fn method_str(&self) -> &'static str { "cloudabi::random_get" } - } -} - - -#[cfg(any(target_os = "macos", target_os = "ios"))] -mod imp { - extern crate libc; - - use {Error, ErrorKind}; - use super::OsRngImpl; - - use std::io; - use self::libc::{c_int, size_t}; - - #[derive(Clone, Debug)] - pub struct OsRng; - - enum SecRandom {} - - #[allow(non_upper_case_globals)] - const kSecRandomDefault: *const SecRandom = 0 as *const SecRandom; - - #[link(name = "Security", kind = "framework")] - extern { - fn SecRandomCopyBytes(rnd: *const SecRandom, - count: size_t, bytes: *mut u8) -> c_int; - } - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { Ok(OsRng) } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - let ret = unsafe { - SecRandomCopyBytes(kSecRandomDefault, - dest.len() as size_t, - dest.as_mut_ptr()) - }; - if ret == -1 { - Err(Error::with_cause( - ErrorKind::Unavailable, - "couldn't generate random bytes", - io::Error::last_os_error())) - } else { - Ok(()) - } - } - - fn method_str(&self) -> &'static str { "SecRandomCopyBytes" } - } -} - - -#[cfg(target_os = "freebsd")] -mod imp { - extern crate libc; - - use {Error, ErrorKind}; - use super::OsRngImpl; - - use std::ptr; - use std::io; - - #[derive(Clone, Debug)] - pub struct OsRng; - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { Ok(OsRng) } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - let mib = [libc::CTL_KERN, libc::KERN_ARND]; - let mut len = dest.len(); - let ret = unsafe { - libc::sysctl(mib.as_ptr(), mib.len() as libc::c_uint, - dest.as_mut_ptr() as *mut _, &mut len, - ptr::null(), 0) - }; - if ret == -1 || len != dest.len() { - return Err(Error::with_cause( - ErrorKind::Unavailable, - "kern.arandom sysctl failed", - io::Error::last_os_error())); - } - Ok(()) - } - - fn max_chunk_size(&self) -> usize { 256 } - - fn method_str(&self) -> &'static str { "kern.arandom" } - } -} - - -#[cfg(any(target_os = "openbsd", target_os = "bitrig"))] -mod imp { - extern crate libc; - - use {Error, ErrorKind}; - use super::OsRngImpl; - - use std::io; - - #[derive(Clone, Debug)] - pub struct OsRng; - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { Ok(OsRng) } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - let ret = unsafe { - libc::getentropy(dest.as_mut_ptr() as *mut libc::c_void, dest.len()) - }; - if ret == -1 { - return Err(Error::with_cause( - ErrorKind::Unavailable, - "getentropy failed", - io::Error::last_os_error())); - } - Ok(()) - } - - fn max_chunk_size(&self) -> usize { 256 } - - fn method_str(&self) -> &'static str { "getentropy" } - } -} - - -#[cfg(target_os = "redox")] -mod imp { - use Error; - use super::random_device; - use super::OsRngImpl; - use std::fs::File; - - #[derive(Clone, Debug)] - pub struct OsRng(); - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { - random_device::open("rand:", &|p| File::open(p))?; - Ok(OsRng()) - } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - random_device::read(dest) - } - - fn method_str(&self) -> &'static str { "'rand:'" } - } -} - - -#[cfg(target_os = "fuchsia")] -mod imp { - extern crate fuchsia_zircon; - - use {Error, ErrorKind}; - use super::OsRngImpl; - - #[derive(Clone, Debug)] - pub struct OsRng; - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { Ok(OsRng) } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - let mut read = 0; - while read < dest.len() { - match fuchsia_zircon::cprng_draw(&mut dest[read..]) { - Ok(actual) => read += actual, - Err(e) => { - return Err(Error::with_cause( - ErrorKind::Unavailable, - "cprng_draw failed", - e.into_io_error())); - } - }; - } - Ok(()) - } - - fn max_chunk_size(&self) -> usize { - fuchsia_zircon::sys::ZX_CPRNG_DRAW_MAX_LEN - } - - fn method_str(&self) -> &'static str { "cprng_draw" } - } -} - - -#[cfg(windows)] -mod imp { - extern crate winapi; - - use {Error, ErrorKind}; - use super::OsRngImpl; - - use std::io; - - use self::winapi::shared::minwindef::ULONG; - use self::winapi::um::ntsecapi::RtlGenRandom; - use self::winapi::um::winnt::PVOID; - - #[derive(Clone, Debug)] - pub struct OsRng; - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { Ok(OsRng) } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - let ret = unsafe { - RtlGenRandom(dest.as_mut_ptr() as PVOID, dest.len() as ULONG) - }; - if ret == 0 { - return Err(Error::with_cause( - ErrorKind::Unavailable, - "couldn't generate random bytes", - io::Error::last_os_error())); - } - Ok(()) - } - - fn max_chunk_size(&self) -> usize { <ULONG>::max_value() as usize } - - fn method_str(&self) -> &'static str { "RtlGenRandom" } - } -} - - -#[cfg(all(target_arch = "wasm32", - not(target_os = "emscripten"), - feature = "stdweb"))] -mod imp { - use std::mem; - use stdweb::unstable::TryInto; - use stdweb::web::error::Error as WebError; - use {Error, ErrorKind}; - use super::OsRngImpl; - - #[derive(Clone, Debug)] - enum OsRngMethod { - Browser, - Node - } - - #[derive(Clone, Debug)] - pub struct OsRng(OsRngMethod); - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { - let result = js! { - try { - if ( - typeof self === "object" && - typeof self.crypto === "object" && - typeof self.crypto.getRandomValues === "function" - ) { - return { success: true, ty: 1 }; - } - - if (typeof require("crypto").randomBytes === "function") { - return { success: true, ty: 2 }; - } - - return { success: false, error: new Error("not supported") }; - } catch(err) { - return { success: false, error: err }; - } - }; - - if js!{ return @{ result.as_ref() }.success } == true { - let ty = js!{ return @{ result }.ty }; - - if ty == 1 { Ok(OsRng(OsRngMethod::Browser)) } - else if ty == 2 { Ok(OsRng(OsRngMethod::Node)) } - else { unreachable!() } - } else { - let err: WebError = js!{ return @{ result }.error }.try_into().unwrap(); - Err(Error::with_cause(ErrorKind::Unavailable, "WASM Error", err)) - } - } - - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - assert_eq!(mem::size_of::<usize>(), 4); - - let len = dest.len() as u32; - let ptr = dest.as_mut_ptr() as i32; - - let result = match self.0 { - OsRngMethod::Browser => js! { - try { - let array = new Uint8Array(@{ len }); - self.crypto.getRandomValues(array); - HEAPU8.set(array, @{ ptr }); - - return { success: true }; - } catch(err) { - return { success: false, error: err }; - } - }, - OsRngMethod::Node => js! { - try { - let bytes = require("crypto").randomBytes(@{ len }); - HEAPU8.set(new Uint8Array(bytes), @{ ptr }); - - return { success: true }; - } catch(err) { - return { success: false, error: err }; - } - } - }; - - if js!{ return @{ result.as_ref() }.success } == true { - Ok(()) - } else { - let err: WebError = js!{ return @{ result }.error }.try_into().unwrap(); - Err(Error::with_cause(ErrorKind::Unexpected, "WASM Error", err)) - } - } - - fn max_chunk_size(&self) -> usize { 65536 } - - fn method_str(&self) -> &'static str { - match self.0 { - OsRngMethod::Browser => "Crypto.getRandomValues", - OsRngMethod::Node => "crypto.randomBytes", - } - } - } -} - -#[cfg(all(target_arch = "wasm32", - not(target_os = "emscripten"), - not(feature = "stdweb"), - feature = "wasm-bindgen"))] -mod imp { - use __wbg_shims::*; - - use {Error, ErrorKind}; - use super::OsRngImpl; - - #[derive(Clone, Debug)] - pub enum OsRng { - Node(NodeCrypto), - Browser(BrowserCrypto), - } - - impl OsRngImpl for OsRng { - fn new() -> Result<OsRng, Error> { - // First up we need to detect if we're running in node.js or a - // browser. To do this we get ahold of the `this` object (in a bit - // of a roundabout fashion). - // - // Once we have `this` we look at its `self` property, which is - // only defined on the web (either a main window or web worker). - let this = Function::new("return this").call(&JsValue::undefined()); - assert!(this != JsValue::undefined()); - let this = This::from(this); - let is_browser = this.self_() != JsValue::undefined(); - - if !is_browser { - return Ok(OsRng::Node(node_require("crypto"))) - } - - // If `self` is defined then we're in a browser somehow (main window - // or web worker). Here we want to try to use - // `crypto.getRandomValues`, but if `crypto` isn't defined we assume - // we're in an older web browser and the OS RNG isn't available. - let crypto = this.crypto(); - if crypto.is_undefined() { - let msg = "self.crypto is undefined"; - return Err(Error::new(ErrorKind::Unavailable, msg)) - } - - // Test if `crypto.getRandomValues` is undefined as well - let crypto: BrowserCrypto = crypto.into(); - if crypto.get_random_values_fn().is_undefined() { - let msg = "crypto.getRandomValues is undefined"; - return Err(Error::new(ErrorKind::Unavailable, msg)) - } - - // Ok! `self.crypto.getRandomValues` is a defined value, so let's - // assume we can do browser crypto. - Ok(OsRng::Browser(crypto)) - } - - fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> { - match *self { - OsRng::Node(ref n) => n.random_fill_sync(dest), - OsRng::Browser(ref n) => n.get_random_values(dest), - } - Ok(()) - } - - fn max_chunk_size(&self) -> usize { - match *self { - OsRng::Node(_) => usize::max_value(), - OsRng::Browser(_) => { - // see https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues - // - // where it says: - // - // > A QuotaExceededError DOMException is thrown if the - // > requested length is greater than 65536 bytes. - 65536 - } - } - } - - fn method_str(&self) -> &'static str { - match *self { - OsRng::Node(_) => "crypto.randomFillSync", - OsRng::Browser(_) => "crypto.getRandomValues", - } - } - } -} - - -#[cfg(test)] -mod test { - use RngCore; - use super::OsRng; - - #[test] - fn test_os_rng() { - let mut r = OsRng::new().unwrap(); - - r.next_u32(); - r.next_u64(); - - let mut v1 = [0u8; 1000]; - r.fill_bytes(&mut v1); - - let mut v2 = [0u8; 1000]; - r.fill_bytes(&mut v2); - - let mut n_diff_bits = 0; - for i in 0..v1.len() { - n_diff_bits += (v1[i] ^ v2[i]).count_ones(); - } - - // Check at least 1 bit per byte differs. p(failure) < 1e-1000 with random input. - assert!(n_diff_bits >= v1.len() as u32); - } - - #[test] - fn test_os_rng_empty() { - let mut r = OsRng::new().unwrap(); - - let mut empty = [0u8; 0]; - r.fill_bytes(&mut empty); - } - - #[test] - fn test_os_rng_huge() { - let mut r = OsRng::new().unwrap(); - - let mut huge = [0u8; 100_000]; - r.fill_bytes(&mut huge); - } - - #[cfg(not(any(target_arch = "wasm32", target_arch = "asmjs")))] - #[test] - fn test_os_rng_tasks() { - use std::sync::mpsc::channel; - use std::thread; - - let mut txs = vec!(); - for _ in 0..20 { - let (tx, rx) = channel(); - txs.push(tx); - - thread::spawn(move|| { - // wait until all the tasks are ready to go. - rx.recv().unwrap(); - - // deschedule to attempt to interleave things as much - // as possible (XXX: is this a good test?) - let mut r = OsRng::new().unwrap(); - thread::yield_now(); - let mut v = [0u8; 1000]; - - for _ in 0..100 { - r.next_u32(); - thread::yield_now(); - r.next_u64(); - thread::yield_now(); - r.fill_bytes(&mut v); - thread::yield_now(); - } - }); - } - - // start all the tasks - for tx in txs.iter() { - tx.send(()).unwrap(); - } - } -} |