Server side net overflow error.

[wrefgtzweve]

Getting this error pretty frequent on server side, no idea what causes it currently as it's hard to replicate.

Trying to send an overflowed net message!
   0.  Send - [C]:-1
    1.  FlushQueue - addons/wire/lua/wire/wireshared.lua:616
     2.  fn - addons/wire/lua/wire/wireshared.lua:633
      3.  unkown - addons/ulib/lua/ulib/shared/hook.lua:109

[thegrb93]

Looks like whoever wrote the port networking didn't take into account size limits
https://github.com/wiremod/wire/blob/master/lua/wire/wireshared.lua#L610-L615

[Divran]

I think the best solution is to just abort the net message when the limit is reached here https://github.com/wiremod/wire/blob/master/lua/wire/wireshared.lua#L611-L615

and then, add a repeating timer here https://github.com/wiremod/wire/blob/master/lua/wire/wireshared.lua#L633 that runs every frame or whatever until the queue is empty. The other call to FlushQueue, here https://github.com/wiremod/wire/blob/master/lua/wire/wireshared.lua#L621 already has a "timer" in the form of the think hook it's placed in, so that's already handled.

[thegrb93]

You need the client to request more data after it finishes receiving each load. Otherwise, you'll end up kicking the client via an overflow.

[Divran]

You need the client to request more data after it finishes receiving each load. Otherwise, you'll end up kicking the client via an overflow.

could also just make the timer wait 1s between each run instead of waiting 1 frame. also doesn't the net library itself space out transmissions to avoid kicking clients?

[thegrb93]

No, in-fact I'm pretty sure EGP can still kick people

[wrefgtzweve]

still happening a bunch, any status on this?

[thegrb93]

Nobody's worked on it, no

[Fasteroid]

concmd can also cause net library problems:

@name exploits/caught_in_4k (abridged version)
POWER = 1000
runOnTick(1)
for(I=1, POWER){
    concmd("impulse 100")  # toggle flashlight
}

This will lag chat, undo messages, etc... for everyone and will do so for a while even after the chip is removed.
Setting POWER higher can also cause you to disconnect yourself via overflow (but not other clients)

It might be wise to move all of wire's user-controlled net library usage behind an abstraction layer. If this were done, a unified antispam system shared among all wire entities could be designed as to prevent any future variants of this attack.

@ me if you want this developed

[thegrb93]

That's completely unrelated to this, but yeah it needs to be fixed

[Fasteroid]

That's completely unrelated to this, but yeah it needs to be fixed

Brought it up since you mentioned EGP

[thegrb93]

Fixed by #3251