[#107] common: Check committee witness for contract update

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

common/ir.go

@@ -55,6 +55,12 @@ func AlphabetAddress() []byte {
 	return Multiaddress(alphabet, false)
 }
 
+// CommitteeAddress returns multi address of committee.
+func CommitteeAddress() []byte {
+	committee := neo.GetCommittee()
+	return Multiaddress(committee, true)
+}
+
 // Multiaddress returns default multi signature account address for N keys.
 // If committee set to true, then it is `M = N/2+1` committee account.
 func Multiaddress(n []interop.PublicKey, committee bool) []byte {
@@ -63,12 +69,7 @@ func Multiaddress(n []interop.PublicKey, committee bool) []byte {
 		threshold = len(n)/2 + 1
 	}
 
-	keys := []interop.PublicKey{}
-	for _, key := range n {
-		keys = append(keys, key)
-	}
-
-	return contract.CreateMultisigAccount(threshold, keys)
+	return contract.CreateMultisigAccount(threshold, n)
 }
 
 func keysToNodes(list []interop.PublicKey) []IRNode {

common/update.go

@@ -1,22 +1,10 @@
 package common
 
 import (
-	"github.com/nspcc-dev/neo-go/pkg/interop"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
-	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
 )
 
-const OwnerKey = "contractOwner"
-
-// HasUpdateAccess returns true if contract can be initialized, re-initialized
-// or migrated.
-func HasUpdateAccess(ctx storage.Context) bool {
-	data := storage.Get(ctx, OwnerKey)
-	if data == nil { // contract has not been initialized yet, return true
-		return true
-	}
-
-	owner := data.(interop.Hash160)
-
-	return runtime.CheckWitness(owner)
+// HasUpdateAccess returns true if contract can be updated.
+func HasUpdateAccess() bool {
+	return runtime.CheckWitness(CommitteeAddress())
 }