Re: uevent buffer overflow in input layer

[Dmitry Torokhov]

On Tuesday 24 January 2006 00:03, Greg KH wrote:
> On Mon, Jan 23, 2006 at 10:43:41AM +1100, Benjamin Herrenschmidt wrote:
> > Current -git as of today does this on an x86 box with a logitech USB
> > keyboard:
> > 
> > (the $$$ is debug stuff I added to print_modalias(), size is the size
> > passed in and "Total len" is the value of "len" before returning). We
> > end up overflowing, thus we pass a negative size to snprintf which
> > causes the WARN_ON. Bumping the uevent buffer size in lib/kobject_uevent.c
> > from 1024 to 2048 seems to fix the oops and /dev/input/mice is now properly
> > created and works (it doesn't without the fix, X fails and we end up back
> > in console with a dead keyboard).
> > 
> > I'm not sure it's the correct solution as I'm not too familiar with the
> > uevent code though, so I'll let you guys decide on the proper approach.
> 
> Yes, input has some big strings, I'd recommend bumping it up like you
> suggest.
> 
> Care to make up a patch as you found the problem and should get the
> credit?  :)
> 

Actually, is it too late to convert modalias data to the same format
(bitmap) we are using in /proc/bus/input/devices (keeping cutting key
info at KEY_MIN_INTERESTING)? It looks like it will be more compact
and let us keep 1024 bytes buffer...

-- 
Dmitry
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