core, dex: use block hash as witness data (#160)

Using only state root and receipt root as witness data can not protect
other fields in block header, ex: bloom, difficulty, gas limit, gas
used...
So that everyone can manipulate these fields to create as many valid blocks
at the same height as he want. Although this will not effect the state,
one can spam us when syncing.

Using block hash as witness data can solve this.

1 files changed, 7 insertions, 31 deletions

diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index 45eb191f2..967d0d3c5 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -1662,20 +1662,12 @@ func TestProcessBlock(t *testing.T) {
 	for i := 0; i < processNum; i++ {
 		var witnessDataBytes []byte
 		if i == 0 {
-			witnessData := types.WitnessData{
-				Root:        gspec.ToBlock(nil).Root(),
-				ReceiptHash: gspec.ToBlock(nil).ReceiptHash(),
-			}
-			witnessDataBytes, err = rlp.EncodeToBytes(&witnessData)
+			witnessDataBytes, err = rlp.EncodeToBytes(gspec.ToBlock(nil).Hash())
 			if err != nil {
 				t.Fatalf("rlp encode fail: %v", err)
 			}
 		} else {
-			witnessData := types.WitnessData{
-				Root:        chain.CurrentBlock().Root(),
-				ReceiptHash: chain.CurrentBlock().ReceiptHash(),
-			}
-			witnessDataBytes, err = rlp.EncodeToBytes(&witnessData)
+			witnessDataBytes, err = rlp.EncodeToBytes(chain.CurrentBlock().Hash())
 			if err != nil {
 				t.Fatalf("rlp encode fail: %v", err)
 			}
@@ -1723,11 +1715,7 @@ func TestProcessBlock(t *testing.T) {
 	}
 
 	// Validate witness fail with unknown block.
-	witnessData := types.WitnessData{
-		Root:        chain.CurrentBlock().Root(),
-		ReceiptHash: chain.CurrentBlock().ReceiptHash(),
-	}
-	witnessDataBytes, err := rlp.EncodeToBytes(&witnessData)
+	witnessDataBytes, err := rlp.EncodeToBytes(chain.CurrentBlock().Hash())
 	if err != nil {
 		t.Fatalf("rlp encode fail: %v", err)
 	}
@@ -1746,11 +1734,7 @@ func TestProcessBlock(t *testing.T) {
 	}
 
 	// Validate witness fail with unexpected root.
-	witnessData = types.WitnessData{
-		Root:        chain.CurrentBlock().Root(),
-		ReceiptHash: chain.CurrentBlock().ReceiptHash(),
-	}
-	witnessDataBytes, err = rlp.EncodeToBytes(&witnessData)
+	witnessDataBytes, err = rlp.EncodeToBytes(chain.CurrentBlock().Hash())
 	if err != nil {
 		t.Fatalf("rlp encode fail: %v", err)
 	}
@@ -1764,16 +1748,12 @@ func TestProcessBlock(t *testing.T) {
 		Height: processNum - 1,
 		Data:   witnessDataBytes,
 	})
-	if err == nil || !strings.Contains(err.Error(), "invalid witness root") {
+	if err == nil || !strings.Contains(err.Error(), "invalid witness block") {
 		t.Fatalf("not expected fail: %v", err)
 	}
 
 	// Apply transaction fail with insufficient fund.
-	witnessData = types.WitnessData{
-		Root:        chain.CurrentBlock().Root(),
-		ReceiptHash: chain.CurrentBlock().ReceiptHash(),
-	}
-	witnessDataBytes, err = rlp.EncodeToBytes(&witnessData)
+	witnessDataBytes, err = rlp.EncodeToBytes(chain.CurrentBlock().Hash())
 	if err != nil {
 		t.Fatalf("rlp encode fail: %v", err)
 	}
@@ -1801,11 +1781,7 @@ func TestProcessBlock(t *testing.T) {
 	}
 
 	// Apply transaction fail with nonce too height.
-	witnessData = types.WitnessData{
-		Root:        chain.CurrentBlock().Root(),
-		ReceiptHash: chain.CurrentBlock().ReceiptHash(),
-	}
-	witnessDataBytes, err = rlp.EncodeToBytes(&witnessData)
+	witnessDataBytes, err = rlp.EncodeToBytes(chain.CurrentBlock().Hash())
 	if err != nil {
 		t.Fatalf("rlp encode fail: %v", err)
 	}