Re: [PATCH] ACPI: thermal: Use strscpy() instead of strcpy()

From: Abdul Rahim
Date: Fri Sep 13 2024 - 14:24:46 EST


On Fri, Sep 13, 2024 at 05:17:58PM GMT, Christophe JAILLET wrote:
> Le 12/09/2024 � 22:59, Abdul Rahim a �crit�:
> > thermal: prefer strscpy() over strcpy()
> >
> > strcpy() is generally considered unsafe and use of strscpy() is
> > recommended [1]
> >
> > this fixes checkpatch warning:
> > WARNING: Prefer strscpy over strcpy
> >
> > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy [1]
> > Signed-off-by: Abdul Rahim <abdul.rahim@xxxxxxxxxxx>
> > ---
> > drivers/acpi/thermal.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> > index 78db38c7076e..a35e40976763 100644
> > --- a/drivers/acpi/thermal.c
> > +++ b/drivers/acpi/thermal.c
> > @@ -796,9 +796,9 @@ static int acpi_thermal_add(struct acpi_device *device)
> > return -ENOMEM;
> > tz->device = device;
> > - strcpy(tz->name, device->pnp.bus_id);
> > - strcpy(acpi_device_name(device), ACPI_THERMAL_DEVICE_NAME);
> > - strcpy(acpi_device_class(device), ACPI_THERMAL_CLASS);
> > + strscpy(tz->name, device->pnp.bus_id);
> > + strscpy(acpi_device_name(device), ACPI_THERMAL_DEVICE_NAME, MAX_ACPI_DEVICE_NAME_LEN);
>
> Why the 3 parameters version here only?
> Is it needed?
>
> CJ
>
> > + strscpy(acpi_device_class(device), ACPI_THERMAL_CLASS);
> > device->driver_data = tz;
> > acpi_thermal_aml_dependency_fix(tz);

You are correct, it's actually not needed.

"The size argument ... is only required when dst is not an array" [1]

And destination buffers here are actually arrays
from `include/acpi/acpi_bus.h`

```
typedef char acpi_bus_id[8];
...
typedef char acpi_device_name[40];
typedef char acpi_device_class[20];
```
https://docs.kernel.org/core-api/kernel-api.html#c.strscpy [1]

I will resend this patch, with the parameter removed.

Thanks,
Abdul Rahim