Chat no longer works after input of some UTF-8 characters

[stweil]

We experienced a "crash" of our local chat system (1.6.4). It was caused by a client who entered some strange UTF-8 characters in her chat text. A short test with your demo shows the same effect: List of visitors no longer worked but continuously tried to reconnect (we got a Loading ... in our older version). So this problem still exists. A test with demo 2.0 was not successful.

[faf]

And what kind of 'strange UTF-8 characters' it was? Could you provide a little bit more information?

[stweil]

Yes. It's not possible to copy those characters here, so here is a screen shot which shows three of them:

[faf]

for now i cannot confirm the bug. ┼ (U+253C) ♂ (U+2642) ‼ (U+203C) doesn't cause any problems. what browser do you use?

[stweil]

We use Firefox 28.0 on Windows 7. I think that I was mistaken about the cause of the problem. I just retried our test, and it failed again. Here is what I did:

• Get file http://www.weilnetz.de/mibew-bad-characters.txt
• Load that file with Windows Notepad
• The file should show several lines which include the UTF-8 characters
• Copy all lines and paste them into the user chat
• The chat now hangs displaying "Reconnecting"

[stweil]

Now I tried the same from an Ubuntu client running Firefox. The data from mibew-bad-characters is not fully visible with a Linux editor. With SciTE it looks like DC3 DLE VT. In vi it looks like ^S ^P ^K^M. When I copied those data in the editor and pasted it into the user chat, I again got a hanging chat with "Reconnecting".

[faf]

I see. So, the problem is in special chars. Well, that's possible...

Frankly, I'm still unable to reproduce the bug, but we'll look into this issue more carefully.

[faf]

Looks like the cause of this bug was the insufficient filtration of special characters. Namely the vertical tabulation. Now it's fixed.

I've patched our demo installation. Please, go ahead and test it, so I could close this bug. :)

[stweil]

We can confirm that the demo now no longer hangs with our test data. Thanks for the fast fix. I assume it will be included in the next version?

[faf]

Sure.

And btw, we'll release Mibew Messenger 1.6.10 next week.