1 files changed, 273 insertions, 0 deletions
diff --git a/third_party/rust/rand_chacha/src/guts.rs b/third_party/rust/rand_chacha/src/guts.rs
new file mode 100644
index 0000000000..cee8cf75d4
--- /dev/null
+++ b/third_party/rust/rand_chacha/src/guts.rs
@@ -0,0 +1,273 @@
+// Copyright 2019 The CryptoCorrosion Contributors
+// Copyright 2020 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.
+
+//! The ChaCha random number generator.
+
+use ppv_lite86::{dispatch, dispatch_light128};
+
+pub use ppv_lite86::Machine;
+use ppv_lite86::{vec128_storage, ArithOps, BitOps32, LaneWords4, MultiLane, StoreBytes, Vec4};
+
+pub(crate) const BLOCK: usize = 64;
+pub(crate) const BLOCK64: u64 = BLOCK as u64;
+const LOG2_BUFBLOCKS: u64 = 2;
+const BUFBLOCKS: u64 = 1 << LOG2_BUFBLOCKS;
+pub(crate) const BUFSZ64: u64 = BLOCK64 * BUFBLOCKS;
+pub(crate) const BUFSZ: usize = BUFSZ64 as usize;
+
+const STREAM_PARAM_NONCE: u32 = 1;
+const STREAM_PARAM_BLOCK: u32 = 0;
+
+#[derive(Clone, PartialEq, Eq)]
+pub struct ChaCha {
+    pub(crate) b: vec128_storage,
+    pub(crate) c: vec128_storage,
+    pub(crate) d: vec128_storage,
+}
+
+#[derive(Clone)]
+pub struct State<V> {
+    pub(crate) a: V,
+    pub(crate) b: V,
+    pub(crate) c: V,
+    pub(crate) d: V,
+}
+
+#[inline(always)]
+pub(crate) fn round<V: ArithOps + BitOps32>(mut x: State<V>) -> State<V> {
+    x.a += x.b;
+    x.d = (x.d ^ x.a).rotate_each_word_right16();
+    x.c += x.d;
+    x.b = (x.b ^ x.c).rotate_each_word_right20();
+    x.a += x.b;
+    x.d = (x.d ^ x.a).rotate_each_word_right24();
+    x.c += x.d;
+    x.b = (x.b ^ x.c).rotate_each_word_right25();
+    x
+}
+
+#[inline(always)]
+pub(crate) fn diagonalize<V: LaneWords4>(mut x: State<V>) -> State<V> {
+    x.b = x.b.shuffle_lane_words3012();
+    x.c = x.c.shuffle_lane_words2301();
+    x.d = x.d.shuffle_lane_words1230();
+    x
+}
+#[inline(always)]
+pub(crate) fn undiagonalize<V: LaneWords4>(mut x: State<V>) -> State<V> {
+    x.b = x.b.shuffle_lane_words1230();
+    x.c = x.c.shuffle_lane_words2301();
+    x.d = x.d.shuffle_lane_words3012();
+    x
+}
+
+impl ChaCha {
+    #[inline(always)]
+    pub fn new(key: &[u8; 32], nonce: &[u8]) -> Self {
+        init_chacha(key, nonce)
+    }
+
+    #[inline(always)]
+    fn pos64<M: Machine>(&self, m: M) -> u64 {
+        let d: M::u32x4 = m.unpack(self.d);
+        ((d.extract(1) as u64) << 32) | d.extract(0) as u64
+    }
+
+    /// Produce 4 blocks of output, advancing the state
+    #[inline(always)]
+    pub fn refill4(&mut self, drounds: u32, out: &mut [u8; BUFSZ]) {
+        refill_wide(self, drounds, out)
+    }
+
+    #[inline(always)]
+    pub fn set_block_pos(&mut self, value: u64) {
+        set_stream_param(self, STREAM_PARAM_BLOCK, value)
+    }
+
+    #[inline(always)]
+    pub fn get_block_pos(&self) -> u64 {
+        get_stream_param(self, STREAM_PARAM_BLOCK)
+    }
+
+    #[inline(always)]
+    pub fn set_nonce(&mut self, value: u64) {
+        set_stream_param(self, STREAM_PARAM_NONCE, value)
+    }
+
+    #[inline(always)]
+    pub fn get_nonce(&self) -> u64 {
+        get_stream_param(self, STREAM_PARAM_NONCE)
+    }
+
+    #[inline(always)]
+    pub fn get_seed(&self) -> [u8; 32] {
+        get_seed(self)
+    }
+}
+
+#[allow(clippy::many_single_char_names)]
+#[inline(always)]
+fn refill_wide_impl<Mach: Machine>(
+    m: Mach, state: &mut ChaCha, drounds: u32, out: &mut [u8; BUFSZ],
+) {
+    let k = m.vec([0x6170_7865, 0x3320_646e, 0x7962_2d32, 0x6b20_6574]);
+    let mut pos = state.pos64(m);
+    let d0: Mach::u32x4 = m.unpack(state.d);
+    pos = pos.wrapping_add(1);
+    let d1 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+    pos = pos.wrapping_add(1);
+    let d2 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+    pos = pos.wrapping_add(1);
+    let d3 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+
+    let b = m.unpack(state.b);
+    let c = m.unpack(state.c);
+    let mut x = State {
+        a: Mach::u32x4x4::from_lanes([k, k, k, k]),
+        b: Mach::u32x4x4::from_lanes([b, b, b, b]),
+        c: Mach::u32x4x4::from_lanes([c, c, c, c]),
+        d: m.unpack(Mach::u32x4x4::from_lanes([d0, d1, d2, d3]).into()),
+    };
+    for _ in 0..drounds {
+        x = round(x);
+        x = undiagonalize(round(diagonalize(x)));
+    }
+    let mut pos = state.pos64(m);
+    let d0: Mach::u32x4 = m.unpack(state.d);
+    pos = pos.wrapping_add(1);
+    let d1 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+    pos = pos.wrapping_add(1);
+    let d2 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+    pos = pos.wrapping_add(1);
+    let d3 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+    pos = pos.wrapping_add(1);
+    let d4 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+
+    let (a, b, c, d) = (
+        x.a.to_lanes(),
+        x.b.to_lanes(),
+        x.c.to_lanes(),
+        x.d.to_lanes(),
+    );
+    let sb = m.unpack(state.b);
+    let sc = m.unpack(state.c);
+    let sd = [m.unpack(state.d), d1, d2, d3];
+    state.d = d4.into();
+    let mut words = out.chunks_exact_mut(16);
+    for ((((&a, &b), &c), &d), &sd) in a.iter().zip(&b).zip(&c).zip(&d).zip(&sd) {
+        (a + k).write_le(words.next().unwrap());
+        (b + sb).write_le(words.next().unwrap());
+        (c + sc).write_le(words.next().unwrap());
+        (d + sd).write_le(words.next().unwrap());
+    }
+}
+
+dispatch!(m, Mach, {
+    fn refill_wide(state: &mut ChaCha, drounds: u32, out: &mut [u8; BUFSZ]) {
+        refill_wide_impl(m, state, drounds, out);
+    }
+});
+
+// Single-block, rounds-only; shared by try_apply_keystream for tails shorter than BUFSZ
+// and XChaCha's setup step.
+dispatch!(m, Mach, {
+    fn refill_narrow_rounds(state: &mut ChaCha, drounds: u32) -> State<vec128_storage> {
+        let k: Mach::u32x4 = m.vec([0x6170_7865, 0x3320_646e, 0x7962_2d32, 0x6b20_6574]);
+        let mut x = State {
+            a: k,
+            b: m.unpack(state.b),
+            c: m.unpack(state.c),
+            d: m.unpack(state.d),
+        };
+        for _ in 0..drounds {
+            x = round(x);
+            x = undiagonalize(round(diagonalize(x)));
+        }
+        State {
+            a: x.a.into(),
+            b: x.b.into(),
+            c: x.c.into(),
+            d: x.d.into(),
+        }
+    }
+});
+
+dispatch_light128!(m, Mach, {
+    fn set_stream_param(state: &mut ChaCha, param: u32, value: u64) {
+        let d: Mach::u32x4 = m.unpack(state.d);
+        state.d = d
+            .insert((value >> 32) as u32, (param << 1) | 1)
+            .insert(value as u32, param << 1)
+            .into();
+    }
+});
+
+dispatch_light128!(m, Mach, {
+    fn get_stream_param(state: &ChaCha, param: u32) -> u64 {
+        let d: Mach::u32x4 = m.unpack(state.d);
+        ((d.extract((param << 1) | 1) as u64) << 32) | d.extract(param << 1) as u64
+    }
+});
+
+dispatch_light128!(m, Mach, {
+    fn get_seed(state: &ChaCha) -> [u8; 32] {
+        let b: Mach::u32x4 = m.unpack(state.b);
+        let c: Mach::u32x4 = m.unpack(state.c);
+        let mut key = [0u8; 32];
+        b.write_le(&mut key[..16]);
+        c.write_le(&mut key[16..]);
+        key
+    }
+});
+
+fn read_u32le(xs: &[u8]) -> u32 {
+    assert_eq!(xs.len(), 4);
+    u32::from(xs[0]) | (u32::from(xs[1]) << 8) | (u32::from(xs[2]) << 16) | (u32::from(xs[3]) << 24)
+}
+
+dispatch_light128!(m, Mach, {
+    fn init_chacha(key: &[u8; 32], nonce: &[u8]) -> ChaCha {
+        let ctr_nonce = [
+            0,
+            if nonce.len() == 12 {
+                read_u32le(&nonce[0..4])
+            } else {
+                0
+            },
+            read_u32le(&nonce[nonce.len() - 8..nonce.len() - 4]),
+            read_u32le(&nonce[nonce.len() - 4..]),
+        ];
+        let key0: Mach::u32x4 = m.read_le(&key[..16]);
+        let key1: Mach::u32x4 = m.read_le(&key[16..]);
+        ChaCha {
+            b: key0.into(),
+            c: key1.into(),
+            d: ctr_nonce.into(),
+        }
+    }
+});
+
+dispatch_light128!(m, Mach, {
+    fn init_chacha_x(key: &[u8; 32], nonce: &[u8; 24], rounds: u32) -> ChaCha {
+        let key0: Mach::u32x4 = m.read_le(&key[..16]);
+        let key1: Mach::u32x4 = m.read_le(&key[16..]);
+        let nonce0: Mach::u32x4 = m.read_le(&nonce[..16]);
+        let mut state = ChaCha {
+            b: key0.into(),
+            c: key1.into(),
+            d: nonce0.into(),
+        };
+        let x = refill_narrow_rounds(&mut state, rounds);
+        let ctr_nonce1 = [0, 0, read_u32le(&nonce[16..20]), read_u32le(&nonce[20..24])];
+        state.b = x.a;
+        state.c = x.d;
+        state.d = ctr_nonce1.into();
+        state
+    }
+});