From d456785bd4572d05dbdf3ad67253987df84a4c13 Mon Sep 17 00:00:00 2001
From: MariusVanDerWijden <m.vanderwijden@live.de>
Date: Tue, 2 Sep 2025 10:21:41 +0200
Subject: [PATCH] core/vm: fix gas computation post-osaka

---
 core/vm/contracts.go | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 48ba3333ec..50d83818b8 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -497,6 +497,9 @@ func calculateIterationCount(expLen uint64, expHead uint256.Int, multiplier uint
 func byzantiumGasCalc(baseLen, expLen, modLen uint64, expHead uint256.Int) uint64 {
 	maxLen := max(baseLen, modLen)
 	multComplexity := byzantiumMultComplexity(maxLen)
+	if multComplexity == math.MaxUint64 {
+		return math.MaxUint64
+	}
 	iterationCount := calculateIterationCount(expLen, expHead, byzantiumMultiplier)
 
 	// Calculate gas: (multComplexity * iterationCount) / byzantiumDivisor
@@ -512,6 +515,9 @@ func byzantiumGasCalc(baseLen, expLen, modLen uint64, expHead uint256.Int) uint6
 func berlinGasCalc(baseLen, expLen, modLen uint64, expHead uint256.Int) uint64 {
 	maxLen := max(baseLen, modLen)
 	multComplexity := berlinMultComplexity(maxLen)
+	if multComplexity == math.MaxUint64 {
+		return math.MaxUint64
+	}
 	iterationCount := calculateIterationCount(expLen, expHead, berlinMultiplier)
 
 	// Calculate gas: (multComplexity * iterationCount) / berlinDivisor
@@ -528,11 +534,13 @@ func berlinGasCalc(baseLen, expLen, modLen uint64, expHead uint256.Int) uint64 {
 func osakaGasCalc(baseLen, expLen, modLen uint64, expHead uint256.Int) uint64 {
 	maxLen := max(baseLen, modLen)
 	multComplexity := osakaMultComplexity(maxLen)
+	if multComplexity == math.MaxUint64 {
+		return math.MaxUint64
+	}
 	iterationCount := calculateIterationCount(expLen, expHead, osakaMultiplier)
 
 	// Calculate gas: (multComplexity * iterationCount) / osakaDivisor
 	carry, gas := bits.Mul64(iterationCount, multComplexity)
-	gas /= osakaDivisor
 	if carry != 0 {
 		return math.MaxUint64
 	}
@@ -608,14 +616,14 @@ func (c *bigModExp) Run(input []byte) ([]byte, error) {
 	} else {
 		input = input[:0]
 	}
-	// Handle a special case when both the base and mod length is zero
-	if baseLen == 0 && modLen == 0 {
-		return []byte{}, nil
-	}
 	// enforce size cap for inputs
 	if c.eip7823 && max(baseLen, expLen, modLen) > 1024 {
 		return nil, fmt.Errorf("one or more of base/exponent/modulus length exceeded 1024 bytes")
 	}
+	// Handle a special case when both the base and mod length is zero
+	if baseLen == 0 && modLen == 0 {
+		return []byte{}, nil
+	}
 	// Retrieve the operands and execute the exponentiation
 	var (
 		base = new(big.Int).SetBytes(getData(input, 0, baseLen))