embed public keys inside ipns records, use for validation

namesys/pb/namesys.proto

@@ -14,4 +14,10 @@ message IpnsEntry {
 	optional uint64 sequence = 5;
 
 	optional uint64 ttl = 6;
+
+	// in order for nodes to properly validate a record upon receipt, they need the public
+	// key associated with it. For old RSA keys, its easiest if we just send this as part of
+	// the record itself. For newer ed25519 keys, the public key can be embedded in the
+	// peerID, making this field unnecessary.
+	optional bytes pubKey = 7;
 }

namesys/publisher.go

@@ -240,13 +240,26 @@ func PutRecordToRouting(ctx context.Context, r routing.ValueStore, k ci.PubKey,
 		return err
 	}
 
+	// if we can't derive the public key from the peerID, embed the entire pubkey in
+	// the record to make the verifiers job easier
+	if extractedPublicKey == nil {
+		pubkeyBytes, err := k.Bytes()
+		if err != nil {
+			return err
+		}
+
+		entry.PubKey = pubkeyBytes
+	}
+
 	namekey, ipnskey := IpnsKeysForID(id)
 
 	go func() {
 		errs <- PublishEntry(ctx, r, ipnskey, entry)
 	}()
 
 	// Publish the public key if a public key cannot be extracted from the ID
+	// TODO: once v0.4.16 is widespread enough, we can stop doing this
+	// and at that point we can even deprecate the /pk/ namespace in the dht
 	if extractedPublicKey == nil {
 		go func() {
 			errs <- PublishPublicKey(ctx, r, namekey, k)

namesys/validator.go

@@ -3,11 +3,13 @@ package namesys
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"time"
 
 	pb "github.com/ipfs/go-ipfs/namesys/pb"
 	peer "gx/ipfs/QmcJukH2sAFjY3HdBKq35WDzWoL3UUu2gt9wdfqZTUyM74/go-libp2p-peer"
 	pstore "gx/ipfs/QmdeiKhUy1TVGBaKxt7y1QmBDLBdisSrLJ1x58Eoj4PXUh/go-libp2p-peerstore"
+	ic "gx/ipfs/Qme1knMqwt1hKZbc1BmQFmnm9f36nyQGwXxPGVpVJ9rMK5/go-libp2p-crypto"
 
 	u "gx/ipfs/QmNiJuT8Ja3hMVpBHXv3Q6dwmperaQ6JjLtpMQgMCD7xvx/go-ipfs-util"
 	record "gx/ipfs/QmTUyK82BVPA6LmSzEJpfEunk9uBaQzWtMsNP917tVj4sT/go-libp2p-record"
@@ -65,10 +67,10 @@ func (v IpnsValidator) Validate(key string, value []byte) error {
 		log.Debugf("failed to parse ipns record key %s into peer ID", pidString)
 		return ErrKeyFormat
 	}
-	pubk := v.KeyBook.PubKey(pid)
-	if pubk == nil {
-		log.Debugf("public key with hash %s not found in peer store", pid)
-		return ErrPublicKeyNotFound
+
+	pubk, err := v.getPublicKey(pid, entry)
+	if err != nil {
+		return fmt.Errorf("getting public key failed: %s", err)
 	}
 
 	// Check the ipns record signature with the public key
@@ -94,6 +96,34 @@ func (v IpnsValidator) Validate(key string, value []byte) error {
 	return nil
 }
 
+func (v IpnsValidator) getPublicKey(pid peer.ID, entry *pb.IpnsEntry) (ic.PubKey, error) {
+	if entry.PubKey != nil {
+		pk, err := ic.UnmarshalPublicKey(entry.PubKey)
+		if err != nil {
+			// TODO: i think this counts as a 'malformed record' and should be discarded
+			log.Debugf("public key in ipns record failed to parse: ", err)
+			return nil, err
+		}
+		expPid, err := peer.IDFromPublicKey(pk)
+		if err != nil {
+			return nil, fmt.Errorf("could not regenerate peerID from pubkey: %s", err)
+		}
+
+		if pid != expPid {
+			return nil, fmt.Errorf("pubkey in record did not match expected pubkey")
+		}
+
+		return pk, nil
+	}
+
+	pubk := v.KeyBook.PubKey(pid)
+	if pubk == nil {
+		log.Debugf("public key with hash %s not found in peer store", pid)
+		return nil, ErrPublicKeyNotFound
+	}
+	return pubk, nil
+}
+
 // IpnsSelectorFunc selects the best record by checking which has the highest
 // sequence number and latest EOL
 func (v IpnsValidator) Select(k string, vals [][]byte) (int, error) {