fix(mix): reject duplicate nullifiers and deposit amount overflow

chain33.fork.toml

@@ -165,6 +165,8 @@ Enable=0
 
 [fork.sub.mix]
 Enable=0
+ForkMixAmountOverflow=0
+ForkMixDupNullifier=0
 
 [fork.sub.multisig]
 Enable=0

chain33.para.toml

@@ -503,6 +503,8 @@ Enable=0
 
 [fork.sub.mix]
 Enable=0
+ForkMixAmountOverflow=0
+ForkMixDupNullifier=0
 
 [fork.sub.unfreeze]
 Enable=0

plugin/dapp/evm/cmd/ci2/chain33.proxyminer.toml

@@ -673,6 +673,8 @@ Enable=0
 
 [fork.sub.mix]
 Enable=0
+ForkMixAmountOverflow=0
+ForkMixDupNullifier=0
 
 [fork.sub.multisig]
 Enable=0

plugin/dapp/mix/executor/deposit.go

@@ -5,6 +5,8 @@
 package executor
 
 import (
+	"math"
+
 	"github.com/33cn/chain33/common/address"
 	"github.com/33cn/chain33/types"
 	mixTy "github.com/33cn/plugin/plugin/dapp/mix/types"
@@ -42,6 +44,8 @@ func (a *action) depositVerify(proof *mixTy.ZkProofInfo) (*mixTy.DepositCircuit,
 4. add new commits to merkle tree
 */
 func (a *action) Deposit(deposit *mixTy.MixDepositAction) (*types.Receipt, error) {
+	cfg := a.api.GetConfig()
+	checkOverflow := cfg.IsDappFork(a.height, mixTy.MixX, mixTy.ForkMixAmountOverflow)
 	var notes []string
 	var sum uint64
 	//1. zk-proof校验
@@ -54,6 +58,10 @@ func (a *action) Deposit(deposit *mixTy.MixDepositAction) (*types.Receipt, error
 		if err != nil {
 			return nil, err
 		}
+		//分叉后校验累加溢出，防止存入金额回绕（同时避免sum超出int64范围）
+		if checkOverflow && v.Uint64() > math.MaxInt64-sum {
+			return nil, errors.Wrapf(mixTy.ErrAmountOverflow, "deposit amount sum overflow,sum=%d,amount=%d", sum, v.Uint64())
+		}
 		sum += v.Uint64()
 		noteHash, err := mixTy.VariableToElement(input.NoteHash)
 		if err != nil {
@@ -63,7 +71,6 @@ func (a *action) Deposit(deposit *mixTy.MixDepositAction) (*types.Receipt, error
 	}
 
 	//存款
-	cfg := a.api.GetConfig()
 	execer, symbol := mixTy.GetAssetExecSymbol(cfg, deposit.AssetExec, deposit.AssetSymbol)
 	accoutDb, err := createAccount(cfg, execer, symbol, a.db)
 	if err != nil {

plugin/dapp/mix/executor/withdraw.go

@@ -86,10 +86,13 @@ func (a *action) withdrawVerify(exec, symbol string, proof *mixTy.ZkProofInfo) (
 3. set nullifier exist
 */
 func (a *action) Withdraw(withdraw *mixTy.MixWithdrawAction) (*types.Receipt, error) {
-	exec, symbol := mixTy.GetAssetExecSymbol(a.api.GetConfig(), withdraw.AssetExec, withdraw.AssetSymbol)
+	cfg := a.api.GetConfig()
+	exec, symbol := mixTy.GetAssetExecSymbol(cfg, withdraw.AssetExec, withdraw.AssetSymbol)
+	checkDupNullifier := cfg.IsDappFork(a.height, mixTy.MixX, mixTy.ForkMixDupNullifier)
 
 	var nulliferSet []string
 	var sumValue uint64
+	nullifierDup := make(map[string]struct{})
 	for _, k := range withdraw.Proofs {
 		input, err := a.withdrawVerify(exec, symbol, k)
 		if err != nil {
@@ -104,6 +107,13 @@ func (a *action) Withdraw(withdraw *mixTy.MixWithdrawAction) (*types.Receipt, er
 		if err != nil {
 			return nil, err
 		}
+		//分叉后校验交易内nullifier唯一：nullifier在交易结束才落库，同一交易内重复proof会双花
+		if checkDupNullifier {
+			if _, ok := nullifierDup[nullHash.String()]; ok {
+				return nil, errors.Wrapf(mixTy.ErrNulliferHashExist, "duplicate nullifier in tx,nullifier=%s", nullHash.String())
+			}
+			nullifierDup[nullHash.String()] = struct{}{}
+		}
 		nulliferSet = append(nulliferSet, nullHash.String())
 	}
 
@@ -112,7 +122,6 @@ func (a *action) Withdraw(withdraw *mixTy.MixWithdrawAction) (*types.Receipt, er
 	}
 
 	//withdraw value
-	cfg := a.api.GetConfig()
 	accoutDb, err := createAccount(cfg, exec, symbol, a.db)
 	if err != nil {
 		return nil, err

plugin/dapp/mix/types/errors.go

@@ -18,6 +18,8 @@ var (
 
 	//ErrNulliferHashExist exist
 	ErrNulliferHashExist = errors.New("ErrNulliferHashExist")
+	//ErrAmountOverflow amount sum overflow
+	ErrAmountOverflow = errors.New("ErrAmountOverflow")
 	//ErrAuthorizeHashExist exist
 	ErrAuthorizeHashExist = errors.New("ErrAuthorizeHashExist")
 

plugin/dapp/mix/types/type.go

@@ -19,6 +19,13 @@ var (
 	glog = log.New("module", MixX)
 )
 
+const (
+	// ForkMixAmountOverflow 修复存款金额以uint64累加无溢出检查的漏洞
+	ForkMixAmountOverflow = "ForkMixAmountOverflow"
+	// ForkMixDupNullifier 修复同一笔Withdraw交易内重复proof双花的漏洞
+	ForkMixDupNullifier = "ForkMixDupNullifier"
+)
+
 func init() {
 	// init executor type
 	types.AllowUserExec = append(types.AllowUserExec, []byte(MixX))
@@ -30,7 +37,8 @@ func init() {
 // InitFork ...
 func InitFork(cfg *types.Chain33Config) {
 	cfg.RegisterDappFork(MixX, "Enable", 0)
-
+	cfg.RegisterDappFork(MixX, ForkMixAmountOverflow, 0)
+	cfg.RegisterDappFork(MixX, ForkMixDupNullifier, 0)
 }
 
 // InitExecutor ...