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Bug 1199 - crash inside X11_GetWindowTitle: SDL_strdup called with a NULL pointer.
Summary: crash inside X11_GetWindowTitle: SDL_strdup called with a NULL pointer.
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: HG 1.2
Hardware: x86_64 Linux
: P2 critical
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-05-02 11:55 UTC by gregory.hainaut
Modified: 2012-02-03 10:26 UTC (History)
0 users

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Description gregory.hainaut 2011-05-02 11:55:30 UTC 
Dear SDL developers,

I got a crash inside the function X11_GetWindowTitle.
First XGetWindowProperty -> return a NULL pointer for propdata
Then SDL_strdup will be called with a null pointer which it cause a crash.

I look at the X11 code, I got the reply.propertyType = None so prop is only NULL assigned and the function XGetWindowProperty return Success.

I do not know if X11 behavior is correct my application has multiple thread, the access to X11 function are probably not thread-safe. Nevertheless I think SDL must handle this special case gracefully without crashing the entire application.

Maybe a check on propdata could be added.

Best Regards,
Gregory
Comment 1 Sam Lantinga 2012-01-06 22:40:30 UTC 
Can you retest with the latest snapshot?
http://www.libsdl.org/tmp/SDL-1.3.zip

Looking at the code, it checks for propdata not being NULL after each call.  It sounds like this is fixed already?

Thanks!
Comment 2 gregory.hainaut 2012-02-03 10:26:51 UTC 
(In reply to comment #1)
> Can you retest with the latest snapshot?
> http://www.libsdl.org/tmp/SDL-1.3.zip
> 
> Looking at the code, it checks for propdata not being NULL after each call.  It
> sounds like this is fixed already?
> 
> Thanks!

Yes that good for me. I close the bug report.

Thanks you very much.