From 9ceb7e56ec88cdb3b63076bcbe744f6927d48387 Mon Sep 17 00:00:00 2001
From: Artyom Pavlov <newpavlov@gmail.com>
Date: Fri, 27 Jan 2023 23:30:37 +0000
Subject: [PATCH] Eliminate potential panic in sys_fill_exact (#334)

---
 src/util_libc.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/util_libc.rs b/src/util_libc.rs
index bd9c7de1..de1455c5 100644
--- a/src/util_libc.rs
+++ b/src/util_libc.rs
@@ -8,6 +8,7 @@
 #![allow(dead_code)]
 use crate::Error;
 use core::{
+    cmp::min,
     mem::MaybeUninit,
     num::NonZeroU32,
     ptr::NonNull,
@@ -78,7 +79,8 @@ pub fn sys_fill_exact(
         } else {
             // We don't check for EOF (ret = 0) as the data we are reading
             // should be an infinite stream of random bytes.
-            buf = &mut buf[(res as usize)..];
+            let len = min(res as usize, buf.len());
+            buf = &mut buf[len..];
         }
     }
     Ok(())