From fff8132b13cf2205ffe598f9e23a54f4274f927d Mon Sep 17 00:00:00 2001
From: David Hill <dhill@mindcry.org>
Date: Tue, 19 May 2020 08:24:02 -0500
Subject: [PATCH] Store signing key in db. (#34)

---
 config.go            | 33 ---------------------------------
 database/database.go | 42 ++++++++++++++++++++++++++++++++++++++++++
 main.go              | 11 +++++++++--
 3 files changed, 51 insertions(+), 35 deletions(-)

diff --git a/config.go b/config.go
index 9dfa460..e663f50 100644
--- a/config.go
+++ b/config.go
@@ -1,9 +1,6 @@
 package main
 
 import (
-	"crypto/ed25519"
-	"crypto/rand"
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -41,8 +38,6 @@ type config struct {
 	WalletPass string  `long:"walletpass" ini-name:"walletpass" description:"Password for dcrwallet RPC connections."`
 	WalletCert string  `long:"walletcert" ini-name:"walletcert" description:"The dcrwallet RPC certificate file."`
 
-	signKey   ed25519.PrivateKey
-	pubKey    ed25519.PublicKey
 	dbPath    string
 	netParams *netParams
 	dcrwCert  []byte
@@ -283,33 +278,5 @@ func loadConfig() (*config, error) {
 	// Set the database path
 	cfg.dbPath = filepath.Join(dataDir, "vsp.db")
 
-	// Set pubKey/signKey. Read from seed file if it exists, otherwise generate
-	// one.
-	seedPath := filepath.Join(cfg.HomeDir, "sign.seed")
-	seed, err := ioutil.ReadFile(seedPath)
-	if err != nil {
-		if !os.IsNotExist(err) {
-			return nil, errors.New("seedPath does not exist")
-		}
-
-		_, cfg.signKey, err = ed25519.GenerateKey(rand.Reader)
-		if err != nil {
-			return nil, fmt.Errorf("failed to generate signing key: %v", err)
-		}
-		err = ioutil.WriteFile(seedPath, cfg.signKey.Seed(), 0400)
-		if err != nil {
-			return nil, fmt.Errorf("failed to save signing key: %v", err)
-		}
-	} else {
-		cfg.signKey = ed25519.NewKeyFromSeed(seed)
-	}
-
-	// Derive pubKey from signKey
-	pubKey, ok := cfg.signKey.Public().(ed25519.PublicKey)
-	if !ok {
-		return nil, fmt.Errorf("failed to cast signing key: %T", pubKey)
-	}
-	cfg.pubKey = pubKey
-
 	return &cfg, nil
 }
diff --git a/database/database.go b/database/database.go
index 80cd5b6..8e3869b 100644
--- a/database/database.go
+++ b/database/database.go
@@ -2,6 +2,8 @@ package database
 
 import (
 	"context"
+	"crypto/ed25519"
+	"crypto/rand"
 	"encoding/binary"
 	"fmt"
 	"sync"
@@ -25,6 +27,8 @@ var (
 	ticketBktK = []byte("ticketbkt")
 	// version is the current database version.
 	versionK = []byte("version")
+	// privateKeyK is the private key.
+	privateKeyK = []byte("privatekey")
 )
 
 // Open initialises and returns an open database. If no database file is found
@@ -72,6 +76,16 @@ func Open(ctx context.Context, shutdownWg *sync.WaitGroup, dbFile string) (*VspD
 				return err
 			}
 
+			// Generate ed25519 key
+			_, signKey, err := ed25519.GenerateKey(rand.Reader)
+			if err != nil {
+				return fmt.Errorf("failed to generate signing key: %v", err)
+			}
+			err = vspBkt.Put(privateKeyK, signKey.Seed())
+			if err != nil {
+				return err
+			}
+
 			// Create ticket bucket.
 			_, err = vspBkt.CreateBucket(ticketBktK)
 			if err != nil {
@@ -88,3 +102,31 @@ func Open(ctx context.Context, shutdownWg *sync.WaitGroup, dbFile string) (*VspD
 
 	return &VspDatabase{db: db}, nil
 }
+
+func (vdb *VspDatabase) KeyPair() (ed25519.PrivateKey, ed25519.PublicKey, error) {
+	var seed []byte
+	err := vdb.db.View(func(tx *bolt.Tx) error {
+		vspBkt := tx.Bucket(vspBktK)
+
+		seed = vspBkt.Get(privateKeyK)
+		if seed == nil {
+			// should not happen
+			return fmt.Errorf("no private key found")
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	signKey := ed25519.NewKeyFromSeed(seed)
+
+	// Derive pubKey from signKey
+	pubKey, ok := signKey.Public().(ed25519.PublicKey)
+	if !ok {
+		return nil, nil, fmt.Errorf("failed to cast signing key: %T", pubKey)
+	}
+
+	return signKey, pubKey, err
+}
diff --git a/main.go b/main.go
index 69c7004..4f6f9bc 100644
--- a/main.go
+++ b/main.go
@@ -61,10 +61,17 @@ func run(ctx context.Context) error {
 		return err
 	}
 
+	signKey, pubKey, err := db.KeyPair()
+	if err != nil {
+		log.Errorf("Failed to get keypair: %v", err)
+		requestShutdown()
+		shutdownWg.Wait()
+		return err
+	}
 	// Create and start webapi server.
 	apiCfg := webapi.Config{
-		SignKey:   cfg.signKey,
-		PubKey:    cfg.pubKey,
+		SignKey:   signKey,
+		PubKey:    pubKey,
 		VSPFee:    cfg.VSPFee,
 		NetParams: cfg.netParams.Params,
 	}