From 304f116b0df475c6d645c31c87af20adc9b133bb Mon Sep 17 00:00:00 2001
From: Tuna <ng.tuna@gmail.com>
Date: Mon, 14 May 2018 18:12:05 +0700
Subject: [PATCH 1/2] add validation in front of mining

---
 cmd/tomo/main.go           |  8 ++++++++
 consensus/clique/clique.go | 13 +++++++++++++
 eth/backend.go             | 20 ++++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/cmd/tomo/main.go b/cmd/tomo/main.go
index 26ebe5ace4..03b8099dc7 100644
--- a/cmd/tomo/main.go
+++ b/cmd/tomo/main.go
@@ -290,6 +290,14 @@ func startNode(ctx *cli.Context, stack *node.Node) {
 		if err := stack.Service(&ethereum); err != nil {
 			utils.Fatalf("Ethereum service not running: %v", err)
 		}
+
+		// Mining only enabled for validator nodes
+		if ok, err := ethereum.ValidateMiner(); err != nil {
+			utils.Fatalf("Can't verify validator permission: %v", err)
+		} else if !ok {
+			utils.Fatalf("Only validators can mine blocks")
+		}
+
 		// Use a reduced number of threads if requested
 		if threads := ctx.GlobalInt(utils.MinerThreadsFlag.Name); threads > 0 {
 			type threaded interface {
diff --git a/consensus/clique/clique.go b/consensus/clique/clique.go
index 2aa4648552..ecf7ef6262 100644
--- a/consensus/clique/clique.go
+++ b/consensus/clique/clique.go
@@ -34,6 +34,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/crypto/sha3"
+	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
@@ -367,6 +368,18 @@ func (c *Clique) verifyCascadingFields(chain consensus.ChainReader, header *type
 	return c.verifySeal(chain, header, parents)
 }
 
+func (c *Clique) GetSnapshot(chain consensus.ChainReader, header *types.Header) (*Snapshot, error) {
+	number := header.Number.Uint64()
+	if number == 0 {
+		return nil, nil
+	}
+	snap, err := c.snapshot(chain, number-1, header.ParentHash, nil)
+	if err != nil {
+		return nil, err
+	}
+	return snap, nil
+}
+
 // snapshot retrieves the authorization snapshot at a given point in time.
 func (c *Clique) snapshot(chain consensus.ChainReader, number uint64, hash common.Hash, parents []*types.Header) (*Snapshot, error) {
 	// Search for a snapshot in memory or on disk for checkpoints
diff --git a/eth/backend.go b/eth/backend.go
index 94aad23101..9d31475b07 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -334,6 +334,26 @@ func (self *Ethereum) SetEtherbase(etherbase common.Address) {
 	self.miner.SetEtherbase(etherbase)
 }
 
+func (s *Ethereum) ValidateMiner() (bool, error) {
+	eb, err := s.Etherbase()
+	if err != nil {
+		return false, err
+	}
+	if c, ok := s.engine.(*clique.Clique); !ok {
+		return false, fmt.Errorf("Only verify miners in Clique protocol")
+	} else {
+		//check if miner's wallet is in set of validators
+		snap, err := c.GetSnapshot(chain, header)
+		if err != nil {
+			return false, fmt.Errorf("Can't verify miner: %v", err)
+		}
+		if _, authorized := snap.Signers[eb]; !authorized {
+			return false, fmt.Errorf("This miner doesn't belong to set of validators")
+		}
+	}
+	return true, nil
+}
+
 func (s *Ethereum) StartMining(local bool) error {
 	eb, err := s.Etherbase()
 	if err != nil {

From f1cf546defec332deb47232b3635bb3b32263bec Mon Sep 17 00:00:00 2001
From: Tuna <ng.tuna@gmail.com>
Date: Tue, 15 May 2018 10:54:52 +0700
Subject: [PATCH 2/2] correct chain, header params

---
 cmd/tomo/main.go           | 2 +-
 consensus/clique/clique.go | 1 -
 eth/backend.go             | 2 +-
 3 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/cmd/tomo/main.go b/cmd/tomo/main.go
index 03b8099dc7..f5c397310c 100644
--- a/cmd/tomo/main.go
+++ b/cmd/tomo/main.go
@@ -295,7 +295,7 @@ func startNode(ctx *cli.Context, stack *node.Node) {
 		if ok, err := ethereum.ValidateMiner(); err != nil {
 			utils.Fatalf("Can't verify validator permission: %v", err)
 		} else if !ok {
-			utils.Fatalf("Only validators can mine blocks")
+			utils.Fatalf("Only validator can mine blocks")
 		}
 
 		// Use a reduced number of threads if requested
diff --git a/consensus/clique/clique.go b/consensus/clique/clique.go
index ecf7ef6262..1157ab00a3 100644
--- a/consensus/clique/clique.go
+++ b/consensus/clique/clique.go
@@ -34,7 +34,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/crypto/sha3"
-	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
diff --git a/eth/backend.go b/eth/backend.go
index 9d31475b07..11e95c1d74 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -343,7 +343,7 @@ func (s *Ethereum) ValidateMiner() (bool, error) {
 		return false, fmt.Errorf("Only verify miners in Clique protocol")
 	} else {
 		//check if miner's wallet is in set of validators
-		snap, err := c.GetSnapshot(chain, header)
+		snap, err := c.GetSnapshot(s.blockchain, s.blockchain.CurrentHeader())
 		if err != nil {
 			return false, fmt.Errorf("Can't verify miner: %v", err)
 		}