Re: [PATCH v2] platform/x86: think-lmi: Fix memory leak when showing current settings

[Armin Wolf]

Am 31.03.23 um 21:14 schrieb Mark Pearson:

> Hi Armin
>
> On Fri, Mar 31, 2023, at 2:09 PM, Armin Wolf wrote:
> > When retriving a item string with tlmi_setting(), the result has to be
> > freed using kfree(). In current_value_show() however, malformed
> > item strings are not freed, causing a memory leak.
> > Fix this by eliminating the early return responsible for this.
> >
> > Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@xxxxxxxxxxxx>
> > Link:
> > https://lore.kernel.org/platform-driver-x86/01e920bc-5882-ba0c-dd15-868bf0eca0b8@xxxxxxxxxxxx/T/#t
> > Fixes: a40cd7ef22fb ("platform/x86: think-lmi: Add WMI interface
> > support on Lenovo platforms")
> > Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
> > ---
> > Changes in v2:
> > - Add Reported-by: and Link: tags
> > ---
> >   drivers/platform/x86/think-lmi.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/platform/x86/think-lmi.c
> > b/drivers/platform/x86/think-lmi.c
> > index cc66f7cbccf2..8cafb9d4016c 100644
> > --- a/drivers/platform/x86/think-lmi.c
> > +++ b/drivers/platform/x86/think-lmi.c
> > @@ -930,10 +930,12 @@ static ssize_t current_value_show(struct kobject
> > *kobj, struct kobj_attribute *a
> >   	/* validate and split from `item,value` -> `value` */
> >   	value = strpbrk(item, ",");
> >   	if (!value || value == item || !strlen(value + 1))
> > -		return -EINVAL;
> > +		ret = -EINVAL;
> > +	else
> > +		ret = sysfs_emit(buf, "%s\n", value + 1);
> >
> > -	ret = sysfs_emit(buf, "%s\n", value + 1);
> >   	kfree(item);
> > +
> >   	return ret;
> >   }
> >
> > --
> > 2.30.2
> Thanks for doing this - it was on my todo list but you beat me to it.
>
> As a minor note - the Fixes tag should, I think, be
> Fixes: 0fdf10e5fc96 ("platform/x86: think-lmi: Split current_value to reflect only the value")
>
> As that's when I believe I introduced the issue.
>
> Mark

Hi,

you are correct, i will send a v3 soon.

Armin Wolf