From c56dd7a3095977f048cf400e32a8684964a676e8 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Wed, 16 Oct 2019 13:23:14 +0200
Subject: [PATCH] params: check fork ordering when initializing new genesis,
 fixes #20136 (#20169)

prevent users from misconfiguring their nodes so that fork ordering is not preserved.
---
 core/blockchain_test.go |  5 +++--
 core/genesis.go         | 15 ++++++++++-----
 params/config.go        | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index e9526cb4e761..21feee902d44 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -1318,7 +1318,7 @@ func TestEIP155Transition(t *testing.T) {
 		funds      = big.NewInt(1000000000)
 		deleteAddr = common.Address{1}
 		gspec      = &Genesis{
-			Config: &params.ChainConfig{ChainID: big.NewInt(1), EIP155Block: big.NewInt(2), HomesteadBlock: new(big.Int)},
+			Config: &params.ChainConfig{ChainID: big.NewInt(1), EIP150Block: big.NewInt(0), EIP155Block: big.NewInt(2), HomesteadBlock: new(big.Int)},
 			Alloc:  GenesisAlloc{address: {Balance: funds}, deleteAddr: {Balance: new(big.Int)}},
 		}
 		genesis = gspec.MustCommit(db)
@@ -1389,7 +1389,7 @@ func TestEIP155Transition(t *testing.T) {
 	}
 
 	// generate an invalid chain id transaction
-	config := &params.ChainConfig{ChainID: big.NewInt(2), EIP155Block: big.NewInt(2), HomesteadBlock: new(big.Int)}
+	config := &params.ChainConfig{ChainID: big.NewInt(2), EIP150Block: big.NewInt(0), EIP155Block: big.NewInt(2), HomesteadBlock: new(big.Int)}
 	blocks, _ = GenerateChain(config, blocks[len(blocks)-1], ethash.NewFaker(), db, 4, func(i int, block *BlockGen) {
 		var (
 			tx      *types.Transaction
@@ -1425,6 +1425,7 @@ func TestEIP161AccountRemoval(t *testing.T) {
 				ChainID:        big.NewInt(1),
 				HomesteadBlock: new(big.Int),
 				EIP155Block:    new(big.Int),
+				EIP150Block:    new(big.Int),
 				EIP158Block:    big.NewInt(2),
 			},
 			Alloc: GenesisAlloc{address: {Balance: funds}},
diff --git a/core/genesis.go b/core/genesis.go
index 8261c18cc9f0..df0c96798031 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -207,6 +207,9 @@ func SetupGenesisBlockWithOverride(db ethdb.Database, genesis *Genesis, override
 	if overrideIstanbul != nil {
 		newcfg.IstanbulBlock = overrideIstanbul
 	}
+	if err := newcfg.CheckConfigForkOrder(); err != nil {
+		return newcfg, common.Hash{}, err
+	}
 	storedcfg := rawdb.ReadChainConfig(db, stored)
 	if storedcfg == nil {
 		log.Warn("Found genesis block without chain config")
@@ -295,6 +298,13 @@ func (g *Genesis) Commit(db ethdb.Database) (*types.Block, error) {
 	if block.Number().Sign() != 0 {
 		return nil, fmt.Errorf("can't commit genesis block with number > 0")
 	}
+	config := g.Config
+	if config == nil {
+		config = params.AllEthashProtocolChanges
+	}
+	if err := config.CheckConfigForkOrder(); err != nil {
+		return nil, err
+	}
 	rawdb.WriteTd(db, block.Hash(), block.NumberU64(), g.Difficulty)
 	rawdb.WriteBlock(db, block)
 	rawdb.WriteReceipts(db, block.Hash(), block.NumberU64(), nil)
@@ -302,11 +312,6 @@ func (g *Genesis) Commit(db ethdb.Database) (*types.Block, error) {
 	rawdb.WriteHeadBlockHash(db, block.Hash())
 	rawdb.WriteHeadFastBlockHash(db, block.Hash())
 	rawdb.WriteHeadHeaderHash(db, block.Hash())
-
-	config := g.Config
-	if config == nil {
-		config = params.AllEthashProtocolChanges
-	}
 	rawdb.WriteChainConfig(db, block.Hash(), config)
 	return block, nil
 }
diff --git a/params/config.go b/params/config.go
index a400485248b9..baa55205c0e0 100644
--- a/params/config.go
+++ b/params/config.go
@@ -415,6 +415,42 @@ func (c *ChainConfig) CheckCompatible(newcfg *ChainConfig, height uint64) *Confi
 	return lasterr
 }
 
+// CheckConfigForkOrder checks that we don't "skip" any forks, geth isn't pluggable enough
+// to guarantee that forks
+func (c *ChainConfig) CheckConfigForkOrder() error {
+	type fork struct {
+		name  string
+		block *big.Int
+	}
+	var lastFork fork
+	for _, cur := range []fork{
+		{"homesteadBlock", c.HomesteadBlock},
+		{"eip150Block", c.EIP150Block},
+		{"eip155Block", c.EIP155Block},
+		{"eip158Block", c.EIP158Block},
+		{"byzantiumBlock", c.ByzantiumBlock},
+		{"constantinopleBlock", c.ConstantinopleBlock},
+		{"petersburgBlock", c.PetersburgBlock},
+		{"istanbulBlock", c.IstanbulBlock},
+	} {
+		if lastFork.name != "" {
+			// Next one must be higher number
+			if lastFork.block == nil && cur.block != nil {
+				return fmt.Errorf("unsupported fork ordering: %v not enabled, but %v enabled at %v",
+					lastFork.name, cur.name, cur.block)
+			}
+			if lastFork.block != nil && cur.block != nil {
+				if lastFork.block.Cmp(cur.block) > 0 {
+					return fmt.Errorf("unsupported fork ordering: %v enabled at %v, but %v enabled at %v",
+						lastFork.name, lastFork.block, cur.name, cur.block)
+				}
+			}
+		}
+		lastFork = cur
+	}
+	return nil
+}
+
 func (c *ChainConfig) checkCompatible(newcfg *ChainConfig, head *big.Int) *ConfigCompatError {
 	if isForkIncompatible(c.HomesteadBlock, newcfg.HomesteadBlock, head) {
 		return newCompatError("Homestead fork block", c.HomesteadBlock, newcfg.HomesteadBlock)