Don't rely on local peer store for remote nodes public keys

README.md

+
 <h1 align="center">
   <a href="libp2p.io"><img width="250" src="https://github.com/libp2p/libp2p/blob/master/logo/alternates/libp2p-logo-alt-2.png?raw=true" alt="libp2p hex logo" /></a>
 </h1>

examples/multipro/LICENSE

+The MIT License (MIT)
+
+Copyright (c) 2014 Juan Batiz-Benet
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

examples/multipro/README.md

@@ -30,8 +30,14 @@ From `multipro` base source folder:
 ## Details
 
 The example creates two LibP2P Hosts supporting 2 protocols: ping and echo.
+
 Each protocol consists RPC-style requests and respones and each request and response is a typed protobufs message (and a go data object).
+
 This is a different pattern then defining a whole p2p protocol as 1 protobuf message with lots of optional fields (as can be observed in various p2p-lib protocols using protobufs such as dht).
+
 The example shows how to match async received responses with their requests. This is useful when processing a response requires access to the request data.
 
+## Author
+
+@avive
 

examples/multipro/node.go

@@ -5,6 +5,8 @@ import (
 	"github.com/gogo/protobuf/proto"
 	host "gx/ipfs/QmRS46AyqtpJBsf1zmQdeizSDEzo1qkWR7rdEuPFAv8237/go-libp2p-host"
 	peer "gx/ipfs/QmXYjuNuxVzXKJCfWasQk1RqkhVLDM9jtUKhqc2WPQmFSB/go-libp2p-peer"
+
+	crypto "gx/ipfs/QmaPbCnUMBohSGo3KnxEa2bHqyJVVeEEcwtqJAYxerieBo/go-libp2p-crypto"
 	"log"
 )
 
@@ -46,7 +48,7 @@ func (n *Node) authenticateMessage(message proto.Message, data *p2p.MessageData)
 		return false
 	}
 
-	return n.verifyData(bin, []byte(sign), peerId, []byte(data.NodePubKey))
+	return n.verifyData(bin, []byte(sign), peerId, data.NodePubKey)
 }
 
 func (n *Node) signProtoMessage(message proto.Message) ([]byte, error) {
@@ -66,20 +68,31 @@ func (n *Node) signData(data []byte) ([]byte, error) {
 // precondition: we have info about the signer peer in the local peer store
 func (n *Node) verifyData(data []byte, signature []byte, peerId peer.ID, pubKeyData []byte) bool {
 
-	// todo: restore pub key from message and not from the local peer store and use it
-	key := n.Peerstore().PubKey(peerId)
+	key, err := crypto.UnmarshalPublicKey(pubKeyData)
+
+	if err != nil {
+		log.Println(err, "Failed to extract key from message key data")
+		return false
+	}
+
+	// extract node id from the provided public key
+	idFromKey, err := peer.IDFromPublicKey(key)
 
-	//todo: fix this
-	//key, err := key.UnmarshalPublicKey(pubKeyData)
+	if err != nil {
+		log.Println(err, "Failed to extract peer id from public key")
+		return false
+	}
 
-	if key == nil {
-		log.Println("Failed to find public key for %s in local peer store.", peerId.String())
+	// verify that message author node id matches the provided public key
+	if idFromKey != peerId {
+		log.Println(err, "Node id and provided public key mismatch")
 		return false
 	}
 
 	res, err := key.Verify(data, signature)
+
 	if err != nil {
-		log.Println	("Error authenticating data")
+		log.Println(err, "Error authenticating data")
 		return false
 	}
 

examples/multipro/protocol.go

@@ -33,7 +33,8 @@ func sendProtoMessage(data proto.Message, s inet.Stream) bool {
 // messageId - unique for requests, copied from request for responses
 func NewMessageData(node *Node, messageId string, gossip bool) *p2p.MessageData {
 
-	// Create protobufs bin data for a public key
+	// Add protobufs bin data for message author public key
+	// this is useful for authenticating  messages forwarded by a node authored by another node
 	nodePubKey, err := node.Peerstore().PubKey(node.ID()).Bytes()
 
 	if err != nil {