[MC-106] Spawn Mob with Stripped metadata crashes the client Created: 24/Oct/12  Updated: 07/Aug/14  Resolved: 08/Nov/12

Status: Closed
Project: Minecraft: Java Edition
Component/s: None
Affects Version/s: Minecraft 1.4.1
Fix Version/s: None

Type: Bug
Reporter: Nuxas Assignee: Unassigned
Resolution: Invalid Votes: 0
Labels: client, crash, packets
Environment:

java version "1.7.0_07"
OpenJDK Runtime Environment (IcedTea7 2.3.2) (7u7-2.3.2a-1ubuntu1)
OpenJDK 64-Bit Server VM (build 23.2-b09, mixed mode)


Attachments: Text File mcbug.txt     Text File mcbugwithextra.txt    
Confirmation Status: Unconfirmed

 Description   

The client is sensitive to missing metadata in packets sent from the server.

A typical example is to strip out the metadata and only send the metadata structure with 0 keys.

Also adding extra values, leaving the existing ones there too does crash the client too. Example in the second attachment, there I added the int value of 123 to the key 73.



 Comments   
Comment by [Mojang] Nathan Adams [ 29/Oct/12 ]

Some things it needs to know. If you don't tell it these things, it can't function. This is just how it is.

Comment by Nuxas [ 28/Oct/12 ]

@Ray Well our proxy is only causing it when I tell it to such as when I want to generate the crash log for this report.

Yes the Minecraft protocol does change and we catch up all the time, but the development would have been a lot easier if the vanilla client simply disconnected rather than crashed and held the computer for half a minute.

I did send a similar report for another but that was closed since it did not affect vanilla client <-> vanilla server. I'm still stand that ones client should not crash for packets it receive over the internet, hover since you are of a different opinion you should close this issue too.

At least it makes a good tool for putting force into the /ban command

Comment by Ray Herring [ 28/Oct/12 ]

Sounds like the proxy you have developed is causing the issues. Just because the proxy has been working for over a year doesn't mean it can't eventually cause an issue, especially when the MC protocols themselves change.

Comment by Cloudy (Aaron Mills) [ 24/Oct/12 ]

While I appreciate the vigor, unless it happens in vanilla and can be caused in vanilla, it isn't really a bug. The client side doesn't need to be robust enough to handle these issues, as they will never happen. If a client could trigger this behaviour on the server side though, then I would be worried.

Comment by Nuxas [ 24/Oct/12 ]

I've developed a proxy that if nothing else passes on the messages as is. it has been working for over a year so I am rather sure the test changes I do to trigger these bugs are bugs in the client.

Comment by Cloudy (Aaron Mills) [ 24/Oct/12 ]

Does this bug occur in vanilla without interference? How did you "strip out the metadata" or "add extra values"?

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