Problem: base fee conversion could panic on overflow (backport #433) (#…

…435)

* Problem: base fee conversion could panic on overflow (#433)

* prevent integer overflow

use sdkmath.MaxBitLen

cleanup

* changelog

---------

Co-authored-by: Brian Luk <brian6.dev@gmail.com>

* Update CHANGELOG.md

Signed-off-by: yihuang <huang@crypto.com>

---------

Signed-off-by: yihuang <huang@crypto.com>
Co-authored-by: yihuang <huang@crypto.com>
Co-authored-by: Brian Luk <brian6.dev@gmail.com>

CHANGELOG.md

@@ -37,6 +37,14 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ## Unreleased
 
+### Bug Fixes
+
+- (feemarket) [#433](https://github.com/crypto-org-chain/ethermint/pull/433) Fix sdk int conversion panic with baseFee.
+
+### Features
+
+## v0.21.x-cronos
+
 ### Features
 
 * (rpc) [#1682](https://github.com/evmos/ethermint/pull/1682) Add config for maximum number of bytes returned from eth_call.

types/int.go

@@ -19,13 +19,23 @@ import (
  fmt "fmt"
  math "math"
  "math/big"
+ "math/bits"
 
  errorsmod "cosmossdk.io/errors"
  sdkmath "cosmossdk.io/math"
  errortypes "github.com/cosmos/cosmos-sdk/types/errors"
 )
 
-const maxBitLen = 256
+const (
+ maxWordLen = sdkmath.MaxBitLen / bits.UintSize
+)
+
+var MaxInt256 *big.Int
+
+func init() {
+ var tmp big.Int
+ MaxInt256 = tmp.Lsh(big.NewInt(1), sdkmath.MaxBitLen).Sub(&tmp, big.NewInt(1))
+}
 
 // SafeInt64 checks for overflows while casting a uint64 to int64 value.
 func SafeInt64(value uint64) (int64, error) {
@@ -52,7 +62,28 @@ func SafeNewIntFromBigInt(i *big.Int) (sdkmath.Int, error) {
  return sdkmath.NewIntFromBigInt(i), nil
 }
 
+// SaturatedNewInt constructs Int from big.Int, truncate if more than 256bits
+func SaturatedNewInt(i *big.Int) sdkmath.Int {
+ if !IsValidInt256(i) {
+ i = MaxInt256
+ }
+ return sdkmath.NewIntFromBigInt(i)
+}
+
 // IsValidInt256 check the bound of 256 bit number
 func IsValidInt256(i *big.Int) bool {
- return i == nil || i.BitLen() <= maxBitLen
+ return i == nil || !bigIntOverflows(i)
+}
+
+// check if the big int overflows,
+// NOTE: copied from cosmos-sdk.
+func bigIntOverflows(i *big.Int) bool {
+ // overflow is defined as i.BitLen() > MaxBitLen
+ // however this check can be expensive when doing many operations.
+ // So we first check if the word length is greater than maxWordLen.
+ // However the most significant word could be zero, hence we still do the bitlen check.
+ if len(i.Bits()) > maxWordLen {
+ return i.BitLen() > sdkmath.MaxBitLen
+ }
+ return false
 }

types/int_test.go

@@ -0,0 +1,18 @@
+package types
+
+import (
+ "math/big"
+ "testing"
+
+ sdkmath "cosmossdk.io/math"
+ "github.com/stretchr/testify/require"
+)
+
+func TestMaxInt256(t *testing.T) {
+ maxInt256Plus1 := new(big.Int).Add(MaxInt256, big.NewInt(1))
+ require.Equal(t, sdkmath.MaxBitLen, MaxInt256.BitLen())
+ require.Equal(t, sdkmath.MaxBitLen+1, maxInt256Plus1.BitLen())
+
+ require.True(t, IsValidInt256(MaxInt256))
+ require.False(t, IsValidInt256(maxInt256Plus1))
+}

x/feemarket/keeper/params.go

@@ -18,6 +18,7 @@ package keeper
 import (
  "math/big"
 
+ ethermint "github.com/evmos/ethermint/types"
  "github.com/evmos/ethermint/x/feemarket/types"
 
  sdk "github.com/cosmos/cosmos-sdk/types"
@@ -79,7 +80,7 @@ func (k Keeper) GetBaseFee(ctx sdk.Context) *big.Int {
 // SetBaseFee set's the base fee in the store
 func (k Keeper) SetBaseFee(ctx sdk.Context, baseFee *big.Int) {
  params := k.GetParams(ctx)
- params.BaseFee = sdk.NewIntFromBigInt(baseFee)
+ params.BaseFee = ethermint.SaturatedNewInt(baseFee)
  err := k.SetParams(ctx, params)
  if err != nil {
  return