fix(levm): handle sdiv with zero dividend and negative divisor (#1241)

**Motivation**

Fixes a bug found by [FuzzingLabs](https://github.com/FuzzingLabs) in
`sdiv` opcode implementation.

**Description**

The error happened when executing sdiv with a zero dividend and a
negative divisor, and returned something that is not zero (it's
negated).

Closes #1199

Author: maximopalopoli

crates/vm/levm/src/opcode_handlers/arithmetic.rs

@@ -75,7 +75,7 @@ impl VM {
 
         let dividend = current_call_frame.stack.pop()?;
         let divisor = current_call_frame.stack.pop()?;
-        if divisor.is_zero() {
+        if divisor.is_zero() || dividend.is_zero() {
             current_call_frame.stack.push(U256::zero())?;
             return Ok(OpcodeSuccess::Continue);
         }
@@ -92,15 +92,16 @@ impl VM {
         } else {
             divisor
         };
-        let Some(quotient) = dividend.checked_div(divisor) else {
-            current_call_frame.stack.push(U256::zero())?;
-            return Ok(OpcodeSuccess::Continue);
-        };
-        let quotient_is_negative = dividend_is_negative ^ divisor_is_negative;
-        let quotient = if quotient_is_negative {
-            negate(quotient)
-        } else {
-            quotient
+        let quotient = match dividend.checked_div(divisor) {
+            Some(quot) => {
+                let quotient_is_negative = dividend_is_negative ^ divisor_is_negative;
+                if quotient_is_negative {
+                    negate(quot)
+                } else {
+                    quot
+                }
+            }
+            None => U256::zero(),
         };
 
         current_call_frame.stack.push(quotient)?;

crates/vm/levm/tests/edge_case_tests.rs

@@ -101,3 +101,16 @@ fn test_is_negative() {
     let mut current_call_frame = vm.call_frames.pop().unwrap();
     vm.execute(&mut current_call_frame);
 }
+
+#[test]
+fn test_sdiv_zero_dividend_and_negative_divisor() {
+    let mut vm = new_vm_with_bytecode(Bytes::copy_from_slice(&[
+        0x7F, 0xC5, 0xD2, 0x46, 0x01, 0x86, 0xF7, 0x23, 0x3C, 0x92, 0x7E, 0x7D, 0xB2, 0xDC, 0xC7,
+        0x03, 0xC0, 0xE5, 0x00, 0xB6, 0x53, 0xCA, 0x82, 0x27, 0x3B, 0x7B, 0xFA, 0xD8, 0x04, 0x5D,
+        0x85, 0xA4, 0x70, 0x5F, 0x05,
+    ]))
+    .unwrap();
+    let mut current_call_frame = vm.call_frames.pop().unwrap();
+    vm.execute(&mut current_call_frame);
+    assert_eq!(current_call_frame.stack.pop().unwrap(), U256::zero());
+}