Update nitrokey crate to 0.2.3

This change updates the nitrokey crate to version 0.2.3. This version
bumps the rand crate used to 0.6.1, which in turn requires an additional
set of dependencies.

Import subrepo nitrokey/:nitrokey at b3e2adc5bb1300441ca74cc7672617c042f3ea31
Import subrepo rand/:rand at 73613ff903512e9503e41cc8ba9eae76269dc598
Import subrepo rustc_version/:rustc_version at 0294f2ba2018bf7be672abd53db351ce5055fa02
Import subrepo semver-parser/:semver-parser at 750da9b11a04125231b1fb293866ca036845acee
Import subrepo semver/:semver at 5eb6db94fa03f4d5c64a625a56188f496be47598

1 files changed, 370 insertions, 0 deletions

diff --git a/rand/src/rngs/adapter/reseeding.rs b/rand/src/rngs/adapter/reseeding.rs
new file mode 100644
index 0000000..016afab
--- /dev/null
+++ b/rand/src/rngs/adapter/reseeding.rs
@@ -0,0 +1,370 @@
+// Copyright 2018 Developers of the Rand project.
+// Copyright 2013 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.
+
+//! A wrapper around another PRNG that reseeds it after it
+//! generates a certain number of random bytes.
+
+use core::mem::size_of;
+
+use rand_core::{RngCore, CryptoRng, SeedableRng, Error, ErrorKind};
+use rand_core::block::{BlockRngCore, BlockRng};
+
+/// A wrapper around any PRNG that implements [`BlockRngCore`], that adds the
+/// ability to reseed it.
+///
+/// `ReseedingRng` reseeds the underlying PRNG in the following cases:
+///
+/// - On a manual call to [`reseed()`].
+/// - After `clone()`, the clone will be reseeded on first use.
+/// - After a process is forked, the RNG in the child process is reseeded within
+///   the next few generated values, depending on the block size of the
+///   underlying PRNG. For [`ChaChaCore`] and [`Hc128Core`] this is a maximum of
+///   15 `u32` values before reseeding.
+/// - After the PRNG has generated a configurable number of random bytes.
+///
+/// # When should reseeding after a fixed number of generated bytes be used?
+///
+/// Reseeding after a fixed number of generated bytes is never strictly
+/// *necessary*. Cryptographic PRNGs don't have a limited number of bytes they
+/// can output, or at least not a limit reachable in any practical way. There is
+/// no such thing as 'running out of entropy'.
+///
+/// Occasionally reseeding can be seen as some form of 'security in depth'. Even
+/// if in the future a cryptographic weakness is found in the CSPRNG being used,
+/// or a flaw in the implementation, occasionally reseeding should make
+/// exploiting it much more difficult or even impossible.
+///
+/// Use [`ReseedingRng::new`] with a `threshold` of `0` to disable reseeding
+/// after a fixed number of generated bytes.
+///
+/// # Error handling
+///
+/// Although unlikely, reseeding the wrapped PRNG can fail. `ReseedingRng` will
+/// never panic but try to handle the error intelligently through some
+/// combination of retrying and delaying reseeding until later.
+/// If handling the source error fails `ReseedingRng` will continue generating
+/// data from the wrapped PRNG without reseeding.
+///
+/// Manually calling [`reseed()`] will not have this retry or delay logic, but
+/// reports the error.
+///
+/// # Example
+///
+/// ```
+/// # extern crate rand;
+/// # extern crate rand_chacha;
+/// # fn main() {
+/// use rand::prelude::*;
+/// use rand_chacha::ChaChaCore; // Internal part of ChaChaRng that
+///                              // implements BlockRngCore
+/// use rand::rngs::OsRng;
+/// use rand::rngs::adapter::ReseedingRng;
+///
+/// let prng = ChaChaCore::from_entropy();
+// FIXME: it is better to use EntropyRng as reseeder, but that doesn't implement
+// clone yet.
+/// let reseeder = OsRng::new().unwrap();
+/// let mut reseeding_rng = ReseedingRng::new(prng, 0, reseeder);
+///
+/// println!("{}", reseeding_rng.gen::<u64>());
+///
+/// let mut cloned_rng = reseeding_rng.clone();
+/// assert!(reseeding_rng.gen::<u64>() != cloned_rng.gen::<u64>());
+/// # }
+/// ```
+///
+/// [`ChaChaCore`]: ../../../rand_chacha/struct.ChaChaCore.html
+/// [`Hc128Core`]: ../../../rand_hc/struct.Hc128Core.html
+/// [`BlockRngCore`]: ../../../rand_core/block/trait.BlockRngCore.html
+/// [`ReseedingRng::new`]: struct.ReseedingRng.html#method.new
+/// [`reseed()`]: struct.ReseedingRng.html#method.reseed
+#[derive(Debug)]
+pub struct ReseedingRng<R, Rsdr>(BlockRng<ReseedingCore<R, Rsdr>>)
+where R: BlockRngCore + SeedableRng,
+      Rsdr: RngCore;
+
+impl<R, Rsdr> ReseedingRng<R, Rsdr>
+where R: BlockRngCore + SeedableRng,
+      Rsdr: RngCore
+{
+    /// Create a new `ReseedingRng` from an existing PRNG, combined with a RNG
+    /// to use as reseeder.
+    ///
+    /// `threshold` sets the number of generated bytes after which to reseed the
+    /// PRNG. Set it to zero to never reseed based on the number of generated
+    /// values.
+    pub fn new(rng: R, threshold: u64, reseeder: Rsdr) -> Self {
+        ReseedingRng(BlockRng::new(ReseedingCore::new(rng, threshold, reseeder)))
+    }
+
+    /// Reseed the internal PRNG.
+    pub fn reseed(&mut self) -> Result<(), Error> {
+        self.0.core.reseed()
+    }
+}
+
+// TODO: this should be implemented for any type where the inner type
+// implements RngCore, but we can't specify that because ReseedingCore is private
+impl<R, Rsdr: RngCore> RngCore for ReseedingRng<R, Rsdr>
+where R: BlockRngCore<Item = u32> + SeedableRng,
+    <R as BlockRngCore>::Results: AsRef<[u32]> + AsMut<[u32]>
+{
+    #[inline(always)]
+    fn next_u32(&mut self) -> u32 {
+        self.0.next_u32()
+    }
+
+    #[inline(always)]
+    fn next_u64(&mut self) -> u64 {
+        self.0.next_u64()
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        self.0.fill_bytes(dest)
+    }
+
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+        self.0.try_fill_bytes(dest)
+    }
+}
+
+impl<R, Rsdr> Clone for ReseedingRng<R, Rsdr>
+where R: BlockRngCore + SeedableRng + Clone,
+      Rsdr: RngCore + Clone
+{
+    fn clone(&self) -> ReseedingRng<R, Rsdr> {
+        // Recreating `BlockRng` seems easier than cloning it and resetting
+        // the index.
+        ReseedingRng(BlockRng::new(self.0.core.clone()))
+    }
+}
+
+impl<R, Rsdr> CryptoRng for ReseedingRng<R, Rsdr>
+where R: BlockRngCore + SeedableRng + CryptoRng,
+      Rsdr: RngCore + CryptoRng {}
+
+#[derive(Debug)]
+struct ReseedingCore<R, Rsdr> {
+    inner: R,
+    reseeder: Rsdr,
+    threshold: i64,
+    bytes_until_reseed: i64,
+    fork_counter: usize,
+}
+
+impl<R, Rsdr> BlockRngCore for ReseedingCore<R, Rsdr>
+where R: BlockRngCore + SeedableRng,
+      Rsdr: RngCore
+{
+    type Item = <R as BlockRngCore>::Item;
+    type Results = <R as BlockRngCore>::Results;
+
+    fn generate(&mut self, results: &mut Self::Results) {
+        let global_fork_counter = fork::get_fork_counter();
+        if self.bytes_until_reseed <= 0 ||
+           self.is_forked(global_fork_counter) {
+            // We get better performance by not calling only `reseed` here
+            // and continuing with the rest of the function, but by directly
+            // returning from a non-inlined function.
+            return self.reseed_and_generate(results, global_fork_counter);
+        }
+        let num_bytes = results.as_ref().len() * size_of::<Self::Item>();
+        self.bytes_until_reseed -= num_bytes as i64;
+        self.inner.generate(results);
+    }
+}
+
+impl<R, Rsdr> ReseedingCore<R, Rsdr>
+where R: BlockRngCore + SeedableRng,
+      Rsdr: RngCore
+{
+    /// Create a new `ReseedingCore`.
+    fn new(rng: R, threshold: u64, reseeder: Rsdr) -> Self {
+        use ::core::i64::MAX;
+        fork::register_fork_handler();
+
+        // Because generating more values than `i64::MAX` takes centuries on
+        // current hardware, we just clamp to that value.
+        // Also we set a threshold of 0, which indicates no limit, to that
+        // value.
+        let threshold =
+            if threshold == 0 { MAX }
+            else if threshold <= MAX as u64 { threshold as i64 }
+            else { MAX };
+
+        ReseedingCore {
+            inner: rng,
+            reseeder,
+            threshold: threshold as i64,
+            bytes_until_reseed: threshold as i64,
+            fork_counter: 0,
+        }
+    }
+
+    /// Reseed the internal PRNG.
+    fn reseed(&mut self) -> Result<(), Error> {
+        R::from_rng(&mut self.reseeder).map(|result| {
+            self.bytes_until_reseed = self.threshold;
+            self.inner = result
+        })
+    }
+
+    fn is_forked(&self, global_fork_counter: usize) -> bool {
+        // In theory, on 32-bit platforms, it is possible for
+        // `global_fork_counter` to wrap around after ~4e9 forks.
+        //
+        // This check will detect a fork in the normal case where
+        // `fork_counter < global_fork_counter`, and also when the difference
+        // between both is greater than `isize::MAX` (wrapped around).
+        //
+        // It will still fail to detect a fork if there have been more than
+        // `isize::MAX` forks, without any reseed in between. Seems unlikely
+        // enough.
+        (self.fork_counter.wrapping_sub(global_fork_counter) as isize) < 0
+    }
+
+    #[inline(never)]
+    fn reseed_and_generate(&mut self,
+                           results: &mut <Self as BlockRngCore>::Results,
+                           global_fork_counter: usize)
+    {
+        if self.is_forked(global_fork_counter) {
+            info!("Fork detected, reseeding RNG");
+        } else {
+            trace!("Reseeding RNG (periodic reseed)");
+        }
+
+        let num_bytes =
+            results.as_ref().len() * size_of::<<R as BlockRngCore>::Item>();
+
+        let threshold = if let Err(e) = self.reseed() {
+            let delay = match e.kind {
+                ErrorKind::Transient => num_bytes as i64,
+                kind @ _ if kind.should_retry() => self.threshold >> 8,
+                _ => self.threshold,
+            };
+            warn!("Reseeding RNG delayed reseeding by {} bytes due to \
+                   error from source: {}", delay, e);
+            delay
+        } else {
+            self.fork_counter = global_fork_counter;
+            self.threshold
+        };
+
+        self.bytes_until_reseed = threshold - num_bytes as i64;
+        self.inner.generate(results);
+    }
+}
+
+impl<R, Rsdr> Clone for ReseedingCore<R, Rsdr>
+where R: BlockRngCore + SeedableRng + Clone,
+      Rsdr: RngCore + Clone
+{
+    fn clone(&self) -> ReseedingCore<R, Rsdr> {
+        ReseedingCore {
+            inner: self.inner.clone(),
+            reseeder: self.reseeder.clone(),
+            threshold: self.threshold,
+            bytes_until_reseed: 0, // reseed clone on first use
+            fork_counter: self.fork_counter,
+        }
+    }
+}
+
+impl<R, Rsdr> CryptoRng for ReseedingCore<R, Rsdr>
+where R: BlockRngCore + SeedableRng + CryptoRng,
+      Rsdr: RngCore + CryptoRng {}
+
+
+#[cfg(all(feature="std", unix, not(target_os="emscripten")))]
+mod fork {
+    extern crate libc;
+
+    use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+    use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT};
+
+    // Fork protection
+    //
+    // We implement fork protection on Unix using `pthread_atfork`.
+    // When the process is forked, we increment `RESEEDING_RNG_FORK_COUNTER`.
+    // Every `ReseedingRng` stores the last known value of the static in
+    // `fork_counter`. If the cached `fork_counter` is less than
+    // `RESEEDING_RNG_FORK_COUNTER`, it is time to reseed this RNG.
+    //
+    // If reseeding fails, we don't deal with this by setting a delay, but just
+    // don't update `fork_counter`, so a reseed is attempted as soon as
+    // possible.
+
+    static RESEEDING_RNG_FORK_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT;
+
+    pub fn get_fork_counter() -> usize {
+        RESEEDING_RNG_FORK_COUNTER.load(Ordering::Relaxed)
+    }
+
+    static FORK_HANDLER_REGISTERED: AtomicBool = ATOMIC_BOOL_INIT;
+
+    extern fn fork_handler() {
+        // Note: fetch_add is defined to wrap on overflow
+        // (which is what we want).
+        RESEEDING_RNG_FORK_COUNTER.fetch_add(1, Ordering::Relaxed);
+    }
+
+    pub fn register_fork_handler() {
+        if FORK_HANDLER_REGISTERED.load(Ordering::Relaxed) == false {
+            unsafe { libc::pthread_atfork(None, None, Some(fork_handler)) };
+            FORK_HANDLER_REGISTERED.store(true, Ordering::Relaxed);
+        }
+    }
+}
+
+#[cfg(not(all(feature="std", unix, not(target_os="emscripten"))))]
+mod fork {
+    pub fn get_fork_counter() -> usize { 0 }
+    pub fn register_fork_handler() {}
+}
+
+
+#[cfg(test)]
+mod test {
+    use {Rng, SeedableRng};
+    use rand_chacha::ChaChaCore;
+    use rngs::mock::StepRng;
+    use super::ReseedingRng;
+
+    #[test]
+    fn test_reseeding() {
+        let mut zero = StepRng::new(0, 0);
+        let rng = ChaChaCore::from_rng(&mut zero).unwrap();
+        let mut reseeding = ReseedingRng::new(rng, 32*4, zero);
+
+        // Currently we only support for arrays up to length 32.
+        // TODO: cannot generate seq via Rng::gen because it uses different alg
+        let mut buf = [0u32; 32]; // Needs to be a multiple of the RNGs result
+                                  // size to test exactly.
+        reseeding.fill(&mut buf);
+        let seq = buf;
+        for _ in 0..10 {
+            reseeding.fill(&mut buf);
+            assert_eq!(buf, seq);
+        }
+    }
+
+    #[test]
+    fn test_clone_reseeding() {
+        let mut zero = StepRng::new(0, 0);
+        let rng = ChaChaCore::from_rng(&mut zero).unwrap();
+        let mut rng1 = ReseedingRng::new(rng, 32*4, zero);
+
+        let first: u32 = rng1.gen();
+        for _ in 0..10 { let _ = rng1.gen::<u32>(); }
+
+        let mut rng2 = rng1.clone();
+        assert_eq!(first, rng2.gen::<u32>());
+    }
+}