survivalfly false positive: hit yourself with an arrow shot/dropped from a punch-II bow, moving in water.

Xayanix commented 7 years ago

Short description of the issue.

When you punch with bow (enchanted: punch II) in water you get randomly teleported back.

Complete output of the ncp version command (please prefer text here).

http://scr.hu/0duk/2yes8

How to reproduce the issue (is it random / always happens / side conditions)?

Happens very often.

Have you made any (noteworthy) changes to the default configuration of NCP?

Default.

Do you run any other special plugins that affect game mechanics next to NC+ (adding skills, machines, adding/changing blocks, other anti cheating)?

No.

Video: https://youtu.be/lfvskH-yh3M

Check: 0:04 0:09 0:13

CaptainObvious0 commented 7 years ago

I can confirm this happens but it causes a very small VL level (1-2 VL). I do not get knocked back as far as you though.

Xayanix commented 7 years ago

Still not fixed.

asofold commented 7 years ago

@Xayanix I misinterpreted the ticket text (did i watch the video!?) - This isn't punching the water with the bow, but hitting yourself with an arrow shot from a bow with punch II on. If this is easy to reproduce, i would really appreciate a debug log, because that really speeds up things by a lot (https://github.com/NoCheatPlus/Docs/wiki/Debugging#on-the-fly-debug-output-for-individual-players). (Tried to adjust the title to make it more obvious ~ complicated to write.) Maybe i'll be able to do something there.

And: Could you in future post the text of the 'ncp version' information (just plain copy and paste from the client or server log, or a gist)? That would make it easier to quickly read issues and relate things to each other.

(I can't always watch youtube and visit screenshot sites / java script - so the more obvious/clear the text, the better - if it's on GitHub it's even better.)

Xayanix commented 7 years ago

https://paste.ee/p/OTvvr

asofold commented 7 years ago

@Xayanix The log seems to be missing a lot of entries - do you have other plugins altering set backs? Even if, there should be more logged about ncp going to set back and set back being overridden - or have you removed cancel actions from the survivalfly actions? The allviolations hook is also disabled?

The shown teleports are also not recognized as set backs, neither as overriding of set backs - so where do those come from ...

Otherwise the hacc tag indicates an issue with water, which might be related (already reproduced):

Sprint+jump (..) into water -> hacc will trigger.

Xayanix commented 7 years ago

The log seems to be missing a lot of entries - do you have other plugins altering set backs?

No. Im running only clear NoCheatPlus with almost default config. It is detected as SurvivalFly.

asofold commented 7 years ago

Plainly the teleport positions in the log are 100% odd:

TeleportCause.PLUGIN, could happen due to:
- Another plugin performing a teleport here.
- There is backport changes in the server mod you are using.
- An outdated version of NCP in use, are you on the latest release or later?
The positions are not recognized as set-back locations (despite tags indicating a set back should happen). Could be:
- Another plugin hooks into NCP and/or does the teleporting.
- ?
There is no logs about NCP going to set back. Could be:
- Another plugin is cancelling violation processing and performing their own set back handling.
- cancel actions are removed from survivalfly.
- (Unlikely: they have been stripped off the log.)

All in all let's ensure:

Are you on the latest release of NCP (or one further build)? https://ci.md-5.net/job/NoCheatPlus/
Are you using other plugins that alter how NCP sets back players (NTAC, PNCP, ...)? ~ 'only clear NCP ...' perhaps not, but still.
("moved too quickly" or "moved wrongly" in the server log for this?)

This is another issue though, i assume the 'hacc' tag is the actual issue.

Xayanix commented 7 years ago

I got only one hook, created by me which does drag down players on survivalfly detect. Tried without it, and problem still exists.

When i remove NoCheatPlus (im using b1087) then there is no any lag back. NCP does detect SurvivalFly when i try to punch myself.

asofold commented 7 years ago

Concerning set back adjustment some edges are described here: https://gist.github.com/asofold/b05c0a17c605e7c69bb30ee5e79a6e7b

I assume the hook cancels violation processing and teleports the player (scheduled or not). In any case the gist may be worth having a look at. -> from build 1088 on it will be enough to use MovingData.setTeleported(adjustedLocation), please only if IViolationData.willCancel() returns false - otherwise nothing is necessary (don't cancel violation processing, don't teleport, ...).

(Still not fixing hacc, though.)

Xayanix commented 7 years ago

Detailed info: https://youtu.be/jeyibNRcq3I Can't describe it better, check it.

asofold commented 7 years ago

@Xayanix I've understood the issue and could reproduce it.

I've just been changing things for how to adjust the set-back position of a player - i suggest having a look at that. Build 1088/1089 will allow a much simpler approach to adjusting the set-back location, so NCP will just use the suggested location for setting back players.

NoCheatPlus / Issues