Re: [patch 3/3] ThinkPad ACPI: fix possible NULL pointer dereference

[Cyrill Gorcunov <gorcunov@gmail.com>]

[Pavel Machek - Fri, Apr 18, 2008 at 02:41:12PM +0200]
| Hi!
| 
| > Fix potential NULL pointer dereference if kstrdup failed
| > 
| > Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
| > 
| > ---
| > 
| > Index: linux-2.6.git/drivers/misc/thinkpad_acpi.c
| > ===================================================================
| > --- linux-2.6.git.orig/drivers/misc/thinkpad_acpi.c	2008-04-16 20:35:34.000000000 +0400
| > +++ linux-2.6.git/drivers/misc/thinkpad_acpi.c	2008-04-16 20:36:38.000000000 +0400
| > @@ -5826,7 +5826,7 @@ static void __init get_thinkpad_model_da
| >  
| >  	tp->model_str = kstrdup(dmi_get_system_info(DMI_PRODUCT_VERSION),
| >  					GFP_KERNEL);
| > -	if (strnicmp(tp->model_str, "ThinkPad", 8) != 0) {
| > +	if (tp->model_str && strnicmp(tp->model_str, "ThinkPad", 8) != 0) {
| >  		kfree(tp->model_str);
| >  		tp->model_str = NULL;
| >  	}
| 
| are you sure? This seems to assume machine is thinkpad if kstrdup
| fails... which is very wrong.
| 

Actually, my patch didn't bring any new into the current driver state,
just add additional check to prevent NULL deref, that's all, so I think
it's fine (but maybe additional printk with info would had been usefull).

		- Cyrill -