Fix version nonce handling

lib/messages.js

@@ -10,8 +10,10 @@
 "use strict";
 
 var objectAssign = Object.assign || require("object-assign");
+var bufferEqual = require("buffer-equal");
 var assert = require("./_util").assert;
 var structs = require("./structs");
+var bmcrypto = require("./crypto");
 var UserAgent = require("./user-agent");
 var util = require("./_util");
 
@@ -43,6 +45,9 @@ exports.getCommand = function(buf) {
   return command.slice(0, firstNonNull).toString("ascii");
 };
 
+// Random nonce used to detect connections to self.
+var randomNonce = bmcrypto.randomBytes(8);
+
 /**
  * `version` message.
  * @see {@link https://bitmessage.org/wiki/Protocol_specification#version}
@@ -51,13 +56,7 @@ exports.getCommand = function(buf) {
  */
 var version = exports.version = {
   /**
-   * Random nonce used to detect connections to self.
+   * Decode `version` message.  
-   * @const {Buffer}
-   */
-  NONCE: new Buffer("20bde0a3355dad78", "hex"),
-
-  /**
-   * Decode `version` message.
    * NOTE: `nonce` is copied.
    * @param {Buffer} buf - Message
    * @return {Object} Decoded `version` structure.
@@ -69,7 +68,7 @@ var version = exports.version = {
   },
 
   /**
-   * Decode `version` message payload.
+   * Decode `version` message payload.  
    * NOTE: `nonce` is copied.
    * @param {Buffer} buf - Message payload
    * @return {Object} Decoded `version` structure.
@@ -85,6 +84,7 @@ var version = exports.version = {
     var addrFrom = structs.net_addr.decode(buf.slice(46, 72), short);
     var nonce = new Buffer(8);
     buf.copy(nonce, 0, 72, 80);
+    assert(!bufferEqual(nonce, randomNonce), "Connection to self");
     var decodedUa = UserAgent.decode(buf.slice(80));
     var decodedStreamNumbers = structs.var_int_list.decode(decodedUa.rest);
     return {
@@ -125,7 +125,7 @@ var version = exports.version = {
     var services = opts.services ||
                    ServicesBitfield().set(ServicesBitfield.NODE_NETWORK);
     var time = opts.time || new Date();
-    var nonce = opts.nonce || version.NONCE;
+    var nonce = opts.nonce || randomNonce;
     assert(nonce.length === 8, "Bad nonce");
     var userAgent = opts.userAgent || UserAgent.SELF;
     var streamNumbers = opts.streamNumbers || [1];

test.js

@@ -407,10 +407,12 @@ describe("Message types", function() {
 
   describe("version", function() {
     it("should encode and decode", function() {
+      var nonce = Buffer(8);
       var encoded = version.encode({
         remoteHost: "1.2.3.4",
         remotePort: 48444,
         port: 8444,
+        nonce: nonce,
       });
       expect(message.decode(encoded).command).to.equal("version");
       var res = version.decode(encoded);
@@ -420,7 +422,7 @@ describe("Message types", function() {
       expect(res.remoteHost).to.equal("1.2.3.4");
       expect(res.remotePort).to.equal(48444);
       expect(res.port).to.equal(8444);
-      expect(bufferEqual(res.nonce, version.NONCE)).to.be.true;
+      expect(bufferEqual(res.nonce, nonce)).to.be.true;
       expect(UserAgent.parse(res.userAgent)).to.deep.equal(UserAgent.SELF);
       expect(res.streamNumbers).to.deep.equal([1]);
       expect(res.length).to.equal(101);
@@ -432,9 +434,18 @@ describe("Message types", function() {
         remotePort: 48444,
         port: 8444,
         userAgent: "/test:0.0.1/",
+        nonce: Buffer(8),
       }));
       expect(res.userAgent).to.equal("/test:0.0.1/");
     });
+
+    it("should fail on connection to self", function() {
+      expect(version.decode.bind(null, version.encode({
+        remoteHost: "1.2.3.4",
+        remotePort: 48444,
+        port: 8444,
+      }))).to.throw(/connection to self/i);
+    });
   });
 
   describe("addr", function() {