On Tue, Sep 19, 2023 at 09:02:49AM +0200, Thomas Weißschuh wrote:
> On 2023-09-19 05:07:55+0000, Justin Stitt wrote:
> > `strncpy` is deprecated for use on NUL-terminated destination strings [1].
> > 
> > A trailing zero is already handled by the kcalloc
> > |   *str = kcalloc(element->string.length + 1, sizeof(u8), GFP_KERNEL);
> > ... which makes memcpy() a suitable replacement to strncpy.
> > 
> > Link: 
> > https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
> >  [1]
> > Link: https://github.com/KSPP/linux/issues/90
> > Cc: [email protected]
> > Signed-off-by: Justin Stitt <[email protected]>
> > ---
> > Changes in v2:
> > - use memcpy over strscpy (thanks Kees)
> > - Link to v1: 
> > https://lore.kernel.org/r/20230914-strncpy-drivers-hwmon-acpi_power_meter-c-v1-1-905297479...@google.com
> > ---
> >  drivers/hwmon/acpi_power_meter.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/hwmon/acpi_power_meter.c 
> > b/drivers/hwmon/acpi_power_meter.c
> > index fa28d447f0df..82e99aec4a33 100644
> > --- a/drivers/hwmon/acpi_power_meter.c
> > +++ b/drivers/hwmon/acpi_power_meter.c
> > @@ -803,7 +803,7 @@ static int read_capabilities(struct 
> > acpi_power_meter_resource *resource)
> >                     goto error;
> >             }
> >  
> > -           strncpy(*str, element->string.pointer, element->string.length);
> > +           memcpy(*str, element->string.pointer, element->string.length);
> 
> Isn't this now essentially the same as kmemdup_nul()?

Ah, yeah, good catch. I should add a note that the reverse of strtomem()
is kmemdup_nul() :)

Justin, can you refactor this to use kmemdup_nul() instead?

-Kees

-- 
Kees Cook

Reply via email to