From 5c5f6affcb6006da0c268f66939ce5b593453449 Mon Sep 17 00:00:00 2001
From: Railroad6230 <railroad6230@proton.me>
Date: Thu, 30 Jan 2025 12:26:46 +0100
Subject: [PATCH] Fix Lehmer64 implementation of `next`. (#2912)

The implementation of [`Lehmer64Rand::next`] performs a mul on `u128`, which
is not checked against overflows. It leads to panic in debug mode.


[`Lehmer64Rand`]: https://github.com/AFLplusplus/LibAFL/blob/fd6271fa356f3addda6db33f37db7e42a2c99bbc/libafl_bolts/src/rands/mod.rs#L373-L376

Co-authored-by: Dongjia "toka" Zhang <tokazerkje@outlook.com>
---
 libafl_bolts/src/rands/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libafl_bolts/src/rands/mod.rs b/libafl_bolts/src/rands/mod.rs
index c55f105b2b..739f4a17b1 100644
--- a/libafl_bolts/src/rands/mod.rs
+++ b/libafl_bolts/src/rands/mod.rs
@@ -371,7 +371,7 @@ impl Rand for Lehmer64Rand {
     #[inline]
     #[expect(clippy::unreadable_literal)]
     fn next(&mut self) -> u64 {
-        self.s *= 0xda942042e4dd58b5;
+        self.s = self.s.wrapping_mul(0xda942042e4dd58b5);
         (self.s >> 64) as u64
     }
 }