Certain MODE messages could access on undefined

[awwright]

Presently I'm looking at

node-irc/lib/irc.js

Lines 229 to 239 in 35ee099

	if ( mode in self.prefixForMode ) {
	// channel user modes
	var user = modeArgs.shift();
	if ( adding ) {
	if ( channel.users[user].indexOf(self.prefixForMode[mode]) === -1 )
	channel.users[user] += self.prefixForMode[mode];
	self.emit('+mode', message.args[0], message.nick, mode, user, message);
	}
	else {
	channel.users[user] = channel.users[user].replace(self.prefixForMode[mode], '');

which does not verify that "user" is actually a user present in the channel.

This has occasionally crashed when a non-user value is passed as an argument:

[01 06:44:12] *** Mode #defocus +q *!*@adsl-76-237-180-172.dsl.chcgil.sbcglobal.net by mrmist
 TypeError: Cannot call method 'indexOf' of undefined
     at irc/lib/irc.js:233:54

Usually it works fine though, and I can't quite figure out why. But examining the code, almost certainly the server is capable of crafting a response that will throw a TypeError, disconnecting the IRC connection, and this should never happen.

On a similar note, the debug should probably look more like so:

                if ( self.opt.debug )
                    util.log("MODE:" + message.args[0] + " sets mode: " + message.args.slice(1).join(' '));

[awwright]

Here's another error, after modifying the file like so:

                        // channel user modes
                        var user = modeArgs.shift();console.log('MODE', user, channel.users[user]);

1 Feb 20:51:45 - MODE:#defocus sets mode: +o eir
MODE eir 
1 Feb 20:51:46 - MODE:#defocus sets mode: -qo *!*@adsl-76-237-180-172.dsl.chcgil.sbcglobal.net eir
MODE *!*@adsl-76-237-180-172.dsl.chcgil.sbcglobal.net undefined

irc/lib/irc.js:637
                    throw err;
                          ^
TypeError: Cannot call method 'replace' of undefined
    at irc/lib/irc.js:239:71
    at Array.forEach (native)
    at Client.<anonymous> (irc/lib/irc.js:226:26)
    at Client.EventEmitter.emit (events.js:126:20)
    at irc/lib/irc.js:634:22
    at Array.forEach (native)
    at Socket.<anonymous> (irc/lib/irc.js:631:15)
    at Socket.EventEmitter.emit (events.js:96:17)
    at TCP.onread (net.js:392:31)

Line in question:

node-irc/lib/irc.js

Line 239 in 35ee099

channel.users[user] = channel.users[user].replace(self.prefixForMode[mode], '');

[awwright]

It seems that it's not actually shifting off arguments when it's supposed to be:

1 Feb 21:13:45 - MODE:#defocus sets mode: +o eir
MODE o { o: '@', v: '+' } eir 
1 Feb 21:13:46 - MODE:#defocus sets mode: -qo *!*@gateway/web/freenode/ip.98.251.112.151 eir
MODE o { o: '@', v: '+' } *!*@gateway/web/freenode/ip.98.251.112.151 undefined

with the following line changed:

                        var user = modeArgs.shift();console.log('MODE', mode, self.prefixForMode, user, channel.users[user]);

[Fauntleroy]

I think I just ran into a similar issue--mode change caused node-irc to attempt to run a method on undefined:

+MODE #freenode ChanServ o eir
-MODE #freenode eir q undefined

C:\Users\Timothy\Repos\irchub\node_modules\irc\lib\irc.js:548
                    throw err;
                          ^
TypeError: Cannot call method 'replace' of undefined
    at self.addListener.channels (C:\Users\Timothy\Repos\irchub\node_modules\irc\lib\irc.js:156:71)
    at Array.forEach (native)
    at Client.<anonymous> (C:\Users\Timothy\Repos\irchub\node_modules\irc\lib\irc.js:143:26)
    at Client.EventEmitter.emit (events.js:126:20)
    at Client.connect (C:\Users\Timothy\Repos\irchub\node_modules\irc\lib\irc.js:545:22)
    at Array.forEach (native)
    at Socket.Client.connect (C:\Users\Timothy\Repos\irchub\node_modules\irc\lib\irc.js:542:15)
    at Socket.EventEmitter.emit (events.js:96:17)
    at TCP.onread (net.js:391:31)

[awwright]

I believe the problem lies here:

                        var modeArg;
                        // channel modes
                        if ( mode.match(/^[bkl]$/) ) {
                            modeArg = modeArgs.shift();
                            if ( modeArg.length === 0 )
                                modeArg = undefined;
                        }

The module is not handling Freenode's +-q argument, and so the +-o mode is getting the argument intended for +-q. This can be replicated in any channel by doing the same, OPing yourself, then passing MODE -qo pattern opuser

I'd make a few changes here, first, the length property is typically reserved for Arrays, for strings, standard boolean identity suffices, and prevents a length lookup on modeArg if it's undefined due to there being no more arguments to be shifted off:

                        var modeArg;
                        // channel modes
                        if ( mode.match(/^[bkl]$/) ) {
                            modeArg = modeArgs.shift() || undefined;
                        }

Second, the module needs to respect the CHANMODES property, and properly differentiate between channel-user modes, channel modes with arguments, channel-user-address modes, and no-argument modes, and emit an error when it doesn't understand one of the modes not explicitly on one of those four lists.

This is hinted nicely on line 252:

node-irc/lib/irc.js

Line 239 in 35ee099

channel.users[user] = channel.users[user].replace(self.prefixForMode[mode], '');

                        // TODO - deal nicely with channel modes that take args

[quentinxs]

I added the basic support for differentiating between the types of modes in late October (see lib/irc.js:64) for servers that send out 005 rpl_isupport upon successfully connecting to them. However neither myself, nor Martyn, have gotten around to fix the parsing of MODE lines received from the server even though it is definitely a big item on the list. If you'd like you could write a fix and submit a pull request and I'm sure Martyn would be happy to take a look.

[awwright]

I'm working on that right now

[seiyria]

Any word on this?

[awwright]

My patch is still awaiting merge.

/me pokes

[seiyria]

Yeah, I saw -- I believe this is the bug that's causing our IRC bot to crash occasionally, so I figured I'd give it a prod anyway.

[basert]

any news to the merge status? My bot keeps crashing on slack IRC because of this

[ghost]

This can be closed.

[jirwin]

Fixed in #351.