From d9c611f91e0812fc7aacbab3ed3c77f4c0705d4e Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Fri, 19 Apr 2019 14:43:37 +0200
Subject: [PATCH] fix unaligned and illegal-provenance reads in next_u64

---
 rand_core/src/block.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/rand_core/src/block.rs b/rand_core/src/block.rs
index 3045b9482f4..6772a18a895 100644
--- a/rand_core/src/block.rs
+++ b/rand_core/src/block.rs
@@ -51,7 +51,7 @@
 //! [`fill_bytes`]: RngCore::fill_bytes
 
 use core::convert::AsRef;
-use core::fmt;
+use core::{fmt, ptr};
 use {RngCore, CryptoRng, SeedableRng, Error};
 use impls::{fill_via_u32_chunks, fill_via_u64_chunks};
 
@@ -183,7 +183,8 @@ where <R as BlockRngCore>::Results: AsRef<[u32]> + AsMut<[u32]>
         let read_u64 = |results: &[u32], index| {
             if cfg!(any(target_arch = "x86", target_arch = "x86_64")) {
                 // requires little-endian CPU supporting unaligned reads:
-                unsafe { *(&results[index] as *const u32 as *const u64) }
+                let ptr: *const u64 = results[index..index+1].as_ptr() as *const u64;
+                unsafe { ptr::read_unaligned(ptr) }
             } else {
                 let x = u64::from(results[index]);
                 let y = u64::from(results[index + 1]);