lcd4linux-devel

[Lcd4linux-devel] [PATCH] Memory issues in plugin_mpd.c

[Robert B. <rb...@ge...>]

Hi,

while testing mpd support in lcd4linux, I encountered a program abort
because of an illegal free() operation. This was caused by the attempt
to free() a char[] on the stack (artist, title and album functions).

While I had a look over the code, I also saw some memleaks in the other
functions (elapsedTime and friends) and a buffer overflow issue for sprintf.

The attached patch against r789 in the 0.10.1 branch should fix the issues.

Regards,

Robert

Re: [Lcd4linux-devel] [PATCH] Memory issues in plugin_mpd.c

[Robert B. <rb...@ge...>]

Robert Buchholz wrote:
> Hi,
> 
> while testing mpd support in lcd4linux, I encountered a program abort
> because of an illegal free() operation. This was caused by the attempt
> to free() a char[] on the stack (artist, title and album functions).
> 
> While I had a look over the code, I also saw some memleaks in the other
> functions (elapsedTime and friends) and a buffer overflow issue for sprintf.
> 
> The attached patch against r789 in the 0.10.1 branch should fix the issues.

I just experienced another crash when the mpd side closes the connection
and the error handling code does some null pointer dereferences.
I revised the patch to gracefully handle losing connections. It still
prints a lot of errors, but the screen will end up blank after a minute
 and when mpd comes back up, it works again.

Robert

Re: [Lcd4linux-devel] [PATCH] Memory issues in plugin_mpd.c

[Michael R. <re...@eu...>]

Hi Robert,

>> The attached patch against r789 in the 0.10.1 branch should fix the issues.
> 
> I just experienced another crash when the mpd side closes the connection
> and the error handling code does some null pointer dereferences.
> I revised the patch to gracefully handle losing connections. It still
> prints a lot of errors, but the screen will end up blank after a minute
>  and when mpd comes back up, it works again.

committed to trunk. Thanks a lot!

What I've seen is that this plugin uses fprintf (STDERR, "blah") to 
report errors. These messages will silently disappear when running as a 
daemon. One really should use the error(), info() and debug() functions 
lcd4linux provides...


bye, Michael

-- 
Michael Reinelt <re...@eu...>
http://home.pages.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781

Re: [Lcd4linux-devel] [PATCH] Memory issues in plugin_mpd.c

[Robert B. <rb...@ge...>]

Michael Reinelt wrote:
> committed to trunk. Thanks a lot!
> 
> What I've seen is that this plugin uses fprintf (STDERR, "blah") to
> report errors. These messages will silently disappear when running as a
> daemon. One really should use the error(), info() and debug() functions
> lcd4linux provides...

Oh, thanks for pointing that out. Here's an update.

Robert

Re: [Lcd4linux-devel] [PATCH] Memory issues in plugin_mpd.c

[Stefan K. <ste...@gm...>]

Robert Buchholz schrieb:
> Hi,
> 
> while testing mpd support in lcd4linux, I encountered a program abort
> because of an illegal free() operation. This was caused by the attempt
> to free() a char[] on the stack (artist, title and album functions).
> 
The Plugin, which is delieverd with lcd4linux is broken.
It shouldn't compile.
I've a running version here, but even no time to send it to the 
developer of lcd4linux.

Stefan Kuhne