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Strange messages in logs

Posted: 14 Nov 2017, 20:29
by KingYodah
Hoi hoi, I was recently checking our server logs, and they were flooded with insane amount of strange messages:

MSG_WriteBits: overflow writing -64778 in 16 bits [field delta_angles[1] offset 0]
MSG_WriteBits: overflow writing -129721 in 16 bits [field delta_angles[0] offset 0]
MSG_WriteBits: overflow writing -64778 in 16 bits [field delta_angles[1] offset 0]
MSG_WriteBits: overflow writing -129721 in 16 bits [field delta_angles[0] offset 0]

There were millions of such or similar messages in logs, the log file is usually in size of MBs or tens of MBs and is usually in txt format, but until server restart the log file grew to enormous 450 MB. Server restart made the messages stop coming, but not long after they started flooding in again. We never saw such messages before. Server had recently JK2MV updated to 1.3, could it be related to it or JK2MV itself? Or what could have been triggering the messages? A bug, attempt to attack the server, maintenance of something? Idk. Very recently these messages don't seem appearing though.

~cheers

Re: Strange messages in logs

Posted: 14 Nov 2017, 23:15
by fau
These are developer messages and should show up only with "developer 1" cvar setting. Make sure it's turned off on your server.

Re: Strange messages in logs

Posted: 16 Nov 2017, 17:06
by KingYodah
fau wrote: 14 Nov 2017, 23:15 These are developer messages and should show up only with "developer 1" cvar setting. Make sure it's turned off on your server.
It was set to "1", okay ty

Re: Strange messages in logs

Posted: 17 Nov 2017, 18:00
by KingYodah
And is it possible to disable those messages in other way? I was told that by changing that cvar to 0 it will affect some things regarding Quake3 UDP message logs or what it is which can be useful to see if someone is trying to attack server.

Re: Strange messages in logs

Posted: 17 Nov 2017, 21:15
by Kevin
Doesn't developer mode log every time someone press "Get new list", check server info, etc? In that case, do you realize how quickly your log could go from empty to so massive you can't find anything?

Should only really be used for debugging and other developer things.

Re: Strange messages in logs

Posted: 18 Nov 2017, 00:15
by KingYodah
Kameleon wrote: 17 Nov 2017, 21:15 Doesn't developer mode log every time someone press "Get new list", check server info, etc? In that case, do you realize how quickly your log could go from empty to so massive you can't find anything?

Should only really be used for debugging and other developer things.
If someone is furiously smashing "Get new list" so hard in order to trigger continuous streak of those messages then I guess so. But that would trigger getinfo/getstatus rather than MSG_WriteBits overflow I think.

Now to track speed, probably depends on frequency of those messages but, there was 4 days span between last 2 restarts and during it log file grew to almost 100 MB size. The first time I restarted server in attempt to stop those messages was 6 days ago, that log file contains period spanning two weeks into past and has 453 MB size.

Re: Strange messages in logs

Posted: 18 Nov 2017, 10:41
by fau
developer 1 is only for development purposes so I don't see it as an issue.

However using these messages to detect dos attacks makes sense, I'll make some of them visible with developer 0 in next release. For more details about attacks you should use system logs though.

Re: Strange messages in logs

Posted: 20 Jan 2018, 22:37
by fau
Ok so in 1.4 these messages no longer appear (unless you enable them with com_debugMessage). Also there is a new dos/ddos protection system and diagnostic messages about attacks will show up without developer 1 and without spamming the console so again I strongly advice to disable /developer 1 on your servers :-)

Re: Strange messages in logs

Posted: 21 Jan 2018, 13:59
by KingYodah
Great, thank you!