Feat: key derivation for libp2p identities

go.mod

@@ -23,6 +23,7 @@ require (
 	github.com/libp2p/go-libp2p-record v0.2.0
 	github.com/libp2p/go-libp2p-routing-helpers v0.7.3
 	github.com/mitchellh/go-server-timing v1.0.1
+	github.com/mr-tron/base58 v1.2.0
 	github.com/multiformats/go-multiaddr v0.11.0
 	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58
 	github.com/prometheus/client_golang v1.16.0
@@ -35,6 +36,7 @@ require (
 	go.opentelemetry.io/otel v1.16.0
 	go.opentelemetry.io/otel/sdk v1.16.0
 	go.opentelemetry.io/otel/trace v1.16.0
+	golang.org/x/crypto v0.12.0
 	golang.org/x/sys v0.11.0
 )
 
@@ -119,7 +121,6 @@ require (
 	github.com/mikioh/tcpinfo v0.0.0-20190314235526-30a79bb1804b // indirect
 	github.com/mikioh/tcpopt v0.0.0-20190314235656-172688c1accc // indirect
 	github.com/minio/sha256-simd v1.0.1 // indirect
-	github.com/mr-tron/base58 v1.2.0 // indirect
 	github.com/multiformats/go-base32 v0.1.0 // indirect
 	github.com/multiformats/go-base36 v0.2.0 // indirect
 	github.com/multiformats/go-multiaddr-dns v0.3.1 // indirect
@@ -172,7 +173,6 @@ require (
 	go.uber.org/fx v1.20.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	go.uber.org/zap v1.25.0 // indirect
-	golang.org/x/crypto v0.12.0 // indirect
 	golang.org/x/exp v0.0.0-20230817173708-d852ddb80c63 // indirect
 	golang.org/x/mod v0.12.0 // indirect
 	golang.org/x/net v0.14.0 // indirect

keys.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"crypto/ed25519"
+	crand "crypto/rand"
+	"crypto/sha256"
+	"errors"
+	"io"
+
+	libp2p "github.com/libp2p/go-libp2p/core/crypto"
+	"github.com/mr-tron/base58"
+	"golang.org/x/crypto/hkdf"
+)
+
+const seedBytes = 32
+
+// newSeed returns a b58 encoded random seed.
+func newSeed() (string, error) {
+	bs := make([]byte, seedBytes)
+	_, err := io.ReadFull(crand.Reader, bs)
+	if err != nil {
+		return "", err
+	}
+	return base58.Encode(bs), nil
+}
+
+// derive derives libp2p keys from a b58-encoded seed.
+func deriveKey(b58secret string, info []byte) (libp2p.PrivKey, error) {
+	secret, err := base58.Decode(b58secret)
+	if err != nil {
+		return nil, err
+	}
+	if len(secret) < seedBytes {
+		return nil, errors.New("derivation seed is too short")
+	}
+
+	hash := sha256.New
+	hkdf := hkdf.New(hash, secret, nil, info)
+	keySeed := make([]byte, ed25519.SeedSize)
+	if _, err := io.ReadFull(hkdf, keySeed); err != nil {
+		return nil, err
+	}
+	key := ed25519.NewKeyFromSeed(keySeed)
+	return libp2p.UnmarshalEd25519PrivateKey(key)
+}

main.go

@@ -16,6 +16,8 @@
 	"time"
 
 	logging "github.com/ipfs/go-log/v2"
+	"github.com/libp2p/go-libp2p/core/crypto"
+	peer "github.com/libp2p/go-libp2p/core/peer"
 	"github.com/urfave/cli/v2"
 	"go.opentelemetry.io/contrib/propagators/autoprop"
 	"go.opentelemetry.io/otel"
@@ -35,6 +37,18 @@
 			Value: "",
 			Usage: "specify the directory that cache data will be stored",
 		},
+		&cli.StringFlag{
+			Name:    "seed",
+			Value:   "",
+			EnvVars: []string{"RAINBOW_SEED"},
+			Usage:   "Specify a seed to derive peerID from (needs --seed-index)",
+		},
+		&cli.IntFlag{
+			Name:    "seed-index",
+			Value:   -1,
+			EnvVars: []string{"RAINBOW_SEED_INDEX"},
+			Usage:   "Specify an index to derivate the peerID from the key (needs --seed)",
+		},
 		&cli.IntFlag{
 			Name:  "gateway-port",
 			Value: 8090,
@@ -93,6 +107,27 @@
 		},
 	}
 
+	app.Commands = []*cli.Command{
+		{
+			Name:  "gen-seed",
+			Usage: "Generate a seed for key derivation",
+			Description: `
+Running this command will generate a random seed and print it. The value can
+be used with the RAINBOW_SEED env-var to use key-derivation from a single seed
+to create libp2p identities for the gateway.
+`,
+			Flags: []cli.Flag{},
+			Action: func(c *cli.Context) error {
+				seed, err := newSeed()
+				if err != nil {
+					return err
+				}
+				fmt.Println(seed)
+				return nil
+			},
+		},
+	}
+
 	app.Name = "rainbow"
 	app.Usage = "a standalone ipfs gateway"
 	app.Version = version
@@ -101,6 +136,21 @@
 		cdns := newCachedDNS(dnsCacheRefreshInterval)
 		defer cdns.Close()
 
+		var priv crypto.PrivKey
+		var err error
+		seed := cctx.String("seed")
+
+		index := cctx.Int("seed-index")
+		if len(seed) > 0 && index >= 0 {
+			priv, err = deriveKey(seed, []byte(fmt.Sprintf("rainbow-%d", index)))
+		} else {
+			keyFile := filepath.Join(ddir, "libp2p.key")
+			priv, err = loadOrInitPeerKey(keyFile)
+		}
+		if err != nil {
+			return err
+		}
+
 		gnd, err := Setup(cctx.Context, Config{
 			DataDir:         ddir,
 			ConnMgrLow:      cctx.Int("connmgr-low"),
@@ -109,7 +159,7 @@
 			MaxMemory:       cctx.Uint64("max-memory"),
 			MaxFD:           cctx.Int("max-fd"),
 			InMemBlockCache: cctx.Int64("inmem-block-cache"),
-			Libp2pKeyFile:   filepath.Join(ddir, "libp2p.key"),
+			Libp2pKey:       priv,
 			RoutingV1:       cctx.String("routing"),
 			KuboRPCURLs:     getEnvs(EnvKuboRPC, DefaultKuboRPC),
 			DHTSharedHost:   cctx.Bool("dht-fallback-shared-host"),
@@ -133,7 +183,12 @@
 			Handler: handler,
 		}
 
-		fmt.Printf("Starting %s %s\n\n", name, version)
+		fmt.Printf("Starting %s %s\n", name, version)
+		pid, err := peer.IDFromPublicKey(priv.GetPublic())
+		if err != nil {
+			return err
+		}
+		fmt.Printf("PeerID: %s\n\n", pid)
 		registerVersionMetric(version)
 
 		tp, shutdown, err := newTracerProvider(cctx.Context)

setup.go

@@ -3,7 +3,9 @@
 import (
 	"context"
 	crand "crypto/rand"
+	"errors"
 	"fmt"
+	"io/fs"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -83,7 +85,7 @@
 	ListenAddrs   []string
 	AnnounceAddrs []string
 
-	Libp2pKeyFile string
+	Libp2pKey crypto.PrivKey
 
 	ConnMgrLow   int
 	ConnMgrHi    int
@@ -102,11 +104,6 @@
 }
 
 func Setup(ctx context.Context, cfg Config) (*Node, error) {
-	peerkey, err := loadOrInitPeerKey(cfg.Libp2pKeyFile)
-	if err != nil {
-		return nil, err
-	}
-
 	ds, err := setupDatastore(cfg)
 	if err != nil {
 		return nil, err
@@ -129,7 +126,7 @@
 		libp2p.ListenAddrStrings(cfg.ListenAddrs...),
 		libp2p.NATPortMap(),
 		libp2p.ConnectionManager(cmgr),
-		libp2p.Identity(peerkey),
+		libp2p.Identity(cfg.Libp2pKey),
 		libp2p.BandwidthReporter(bwc),
 		libp2p.DefaultTransports,
 		libp2p.DefaultMuxers,
@@ -296,7 +293,7 @@
 	bn.Start(bswap)
 
 	err = os.Mkdir("denylists", 0755)
-	if err != nil {
+	if err != nil && !errors.Is(err, fs.ErrExist) {
 		return nil, err
 	}