[#51] balance: Support notary contract

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

balance/balance_contract.go

@@ -113,31 +113,11 @@ func Transfer(from, to interop.Hash160, amount int, data interface{}) bool {
 }
 
 func TransferX(from, to interop.Hash160, amount int, details []byte) bool {
-	var (
+	multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey)
-		n        int    // number of votes for inner ring invoke
+	if !runtime.CheckWitness(multiaddr) {
-		hashTxID []byte // ballot key of the inner ring invocation
-	)
-
-	innerRing := irList()
-	threshold := len(innerRing)/3*2 + 1
-
-	irKey := common.InnerRingInvoker(innerRing)
-	if len(irKey) == 0 {
 		panic("transferX: this method must be invoked from inner ring")
 	}
 
-	fromKnownContract := fromKnownContract(runtime.GetCallingScriptHash())
-	if fromKnownContract {
-		n = threshold
-		runtime.Log("transferX: processed indirect invoke")
-	} else {
-		hashTxID = common.InvokeID([]interface{}{from, to, amount}, []byte("transfer"))
-		n = common.Vote(ctx, hashTxID, irKey)
-	}
-
-	if n >= threshold {
-		common.RemoveVotes(ctx, hashTxID)
-
 	result := token.transfer(ctx, from, to, amount, true, details)
 	if result {
 		runtime.Log("transferX: success")
@@ -149,24 +129,12 @@ func TransferX(from, to interop.Hash160, amount int, details []byte) bool {
 	return result
 }
 
-	return false
-}
-
 func Lock(txID []byte, from, to interop.Hash160, amount, until int) bool {
-	innerRing := irList()
+	multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey)
-	threshold := len(innerRing)/3*2 + 1
+	if !runtime.CheckWitness(multiaddr) {
-
-	irKey := common.InnerRingInvoker(innerRing)
-	if len(irKey) == 0 {
 		panic("lock: this method must be invoked from inner ring")
 	}
 
-	hashTxID := common.InvokeID([]interface{}{txID, from, to, amount, until}, []byte("lock"))
-
-	n := common.Vote(ctx, hashTxID, irKey)
-	if n >= threshold {
-		common.RemoveVotes(ctx, hashTxID)
-
 	lockAccount := Account{
 		Balance: 0,
 		Until:   until,
@@ -182,27 +150,16 @@ func Lock(txID []byte, from, to interop.Hash160, amount, until int) bool {
 
 	runtime.Log("lock: created lock account")
 	runtime.Notify("Lock", txID, from, to, amount, until)
-	}
-
-	runtime.Log("lock: processed invoke from inner ring")
 
 	return true
 }
 
 func NewEpoch(epochNum int) bool {
-	innerRing := irList()
+	multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey)
-	threshold := len(innerRing)/3*2 + 1
+	if !runtime.CheckWitness(multiaddr) {
-
-	irKey := common.InnerRingInvoker(innerRing)
-	if len(irKey) == 0 {
 		panic("epochNum: this method must be invoked from inner ring")
 	}
 
-	epochID := common.InvokeID([]interface{}{epochNum}, []byte("epoch"))
-
-	n := common.Vote(ctx, epochID, irKey)
-	if n >= threshold {
-		common.RemoveVotes(ctx, epochID)
 	it := storage.Find(ctx, []byte{}, storage.KeysOnly)
 	for iterator.Next(it) {
 		addr := iterator.Value(it).([]byte) // it MUST BE `storage.KeysOnly`
@@ -220,28 +177,16 @@ func NewEpoch(epochNum int) bool {
 			token.transfer(ctx, addr, acc.Parent, acc.Balance, true, unlockTransferMsg)
 		}
 	}
-	}
-
-	runtime.Log("newEpoch: processed invoke from inner ring")
 
 	return true
 }
 
 func Mint(to interop.Hash160, amount int, details []byte) bool {
-	innerRing := irList()
+	multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey)
-	threshold := len(innerRing)/3*2 + 1
+	if !runtime.CheckWitness(multiaddr) {
-
+		panic("mint: this method must be invoked from inner ring")
-	irKey := common.InnerRingInvoker(innerRing)
-	if len(irKey) == 0 {
-		panic("burn: this method must be invoked from inner ring")
 	}
 
-	mintID := common.InvokeID([]interface{}{to, amount, details}, []byte("mint"))
-
-	n := common.Vote(ctx, mintID, irKey)
-	if n >= threshold {
-		common.RemoveVotes(ctx, mintID)
-
 	ok := token.transfer(ctx, nil, to, amount, true, details)
 	if !ok {
 		panic("mint: can't transfer assets")
@@ -252,26 +197,16 @@ func Mint(to interop.Hash160, amount int, details []byte) bool {
 	storage.Put(ctx, token.CirculationKey, supply)
 	runtime.Log("mint: assets were minted")
 	runtime.Notify("Mint", to, amount)
-	}
 
 	return true
 }
 
 func Burn(from interop.Hash160, amount int, details []byte) bool {
-	innerRing := irList()
+	multiaddr := common.InnerRingMultiAddressViaStorage(ctx, netmapContractKey)
-	threshold := len(innerRing)/3*2 + 1
+	if !runtime.CheckWitness(multiaddr) {
-
-	irKey := common.InnerRingInvoker(innerRing)
-	if len(irKey) == 0 {
 		panic("burn: this method must be invoked from inner ring")
 	}
 
-	burnID := common.InvokeID([]interface{}{from, amount, details}, []byte("burn"))
-
-	n := common.Vote(ctx, burnID, irKey)
-	if n >= threshold {
-		common.RemoveVotes(ctx, burnID)
-
 	ok := token.transfer(ctx, from, nil, amount, true, details)
 	if !ok {
 		panic("burn: can't transfer assets")
@@ -286,7 +221,6 @@ func Burn(from interop.Hash160, amount int, details []byte) bool {
 	storage.Put(ctx, token.CirculationKey, supply)
 	runtime.Log("burn: assets were burned")
 	runtime.Notify("Burn", from, amount)
-	}
 
 	return true
 }
@@ -389,33 +323,3 @@ func getAccount(ctx storage.Context, key interface{}) Account {
 
 	return Account{}
 }
-
-/*
-   Check if invocation made from known container or audit contracts.
-   This is necessary because calls from these contracts require to do transfer
-   without signature collection (1 invoke transfer).
-
-   IR1, IR2, IR3, IR4 -(4 invokes)-> [ Container Contract ] -(1 invoke)-> [ Balance Contract ]
-
-   We can do 1 invoke transfer if:
-   - invoke happened from inner ring node,
-   - it is indirect invocation from other smart-contract.
-
-   However there is a possible attack, when malicious inner ring node creates
-   malicious smart-contract in morph chain to do inderect call.
-
-   MaliciousIR  -(1 invoke)-> [ Malicious Contract ] -(1 invoke) -> [ Balance Contract ]
-
-   To prevent that, we have to allow 1 invoke transfer from authorised well known
-   smart-contracts, that will be set up at `Init` method.
-*/
-
-func fromKnownContract(caller interop.Hash160) bool {
-	containerContractAddr := storage.Get(ctx, containerContractKey).([]byte)
-
-	return common.BytesEqual(caller, containerContractAddr)
-}
-
-func irList() []common.IRNode {
-	return common.InnerRingListViaStorage(ctx, netmapContractKey)
-}