From f116c855aa03564aee8b0de8fbbf9603b0e33e1d Mon Sep 17 00:00:00 2001
From: Robin Salen <salenrobin@gmail.com>
Date: Sun, 16 Jul 2023 15:01:32 -0400
Subject: [PATCH] Fix risk of division by zero

---
 evm/src/generation/prover_input.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/evm/src/generation/prover_input.rs b/evm/src/generation/prover_input.rs
index af3ffe3a..5253a043 100644
--- a/evm/src/generation/prover_input.rs
+++ b/evm/src/generation/prover_input.rs
@@ -4,6 +4,7 @@ use std::str::FromStr;
 use anyhow::{bail, Error};
 use ethereum_types::{BigEndianHash, H256, U256, U512};
 use itertools::Itertools;
+use num_bigint::BigUint;
 use plonky2::field::types::Field;
 use serde::{Deserialize, Serialize};
 
@@ -203,7 +204,11 @@ impl<F: Field> GenerationState<F> {
         let m_biguint = mem_vec_to_biguint(m);
 
         let prod = a_biguint * b_biguint;
-        let quo = &prod / &m_biguint;
+        let quo = if m_biguint == BigUint::default() {
+            BigUint::default()
+        } else {
+            &prod / &m_biguint
+        };
         let rem = prod - m_biguint * &quo;
 
         (biguint_to_mem_vec(rem), biguint_to_mem_vec(quo))