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: linux-hardening@xxxxxxxxxxxxxxx > > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> > > --- > > 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-v1-1-905297479fe8@xxxxxxxxxx > > --- > > 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
