Re: [PATCH] media: siano: Replace strlcat() with snprintf() in sms_ir_init()

[David Laight <david.laight.linux@gmail.com>]

On Wed, 4 Nov 2026 12:25:17 +0100
Alejandro Colomar <alx+linux-hardening@kernel.org> wrote:

> Hi Mariia,
> 
> > Date: 2026-11-04 01:02:39-0800
> > From: Mariia Nikitash <nikitash.mariiaw@gmail.com>
> >
> > In preparation for removing the deprecated strlcat() API[1],
> > replace the strscpy() and strlcat() calls with a single snprintf()
> > call to construct the IR device path.
> > 
> > Both the source and destination buffers have the same capacity,  
> 
> The line above seems irrelevant, and potentially confusing.
> The size of the input is not important, because since we're appending
> stuff after it, truncation may actually happen.

And gcc's stupid format overflow check is going to complain.

David

> 
> > and the return values are unused. This preserves the resulting
> > string, including truncation behavior.
> > 
> > Link: https://github.com/KSPP/linux/issues/370 [1]
> > Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>  
> 
> Except for the small comment above,
> 
> Reviewed-by: Alejandro Colomar <alx@kernel.org>
> 
> 
> Cheers,
> Alex
> 
> > ---
> >  drivers/media/common/siano/smsir.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/media/common/siano/smsir.c b/drivers/media/common/siano/smsir.c
> > index 283770d583d5..636ff228108b 100644
> > --- a/drivers/media/common/siano/smsir.c
> > +++ b/drivers/media/common/siano/smsir.c
> > @@ -55,8 +55,8 @@ int sms_ir_init(struct smscore_device_t *coredev)
> >  	snprintf(coredev->ir.name, sizeof(coredev->ir.name),
> >  		 "SMS IR (%s)", sms_get_board(board_id)->name);
> >  
> > -	strscpy(coredev->ir.phys, coredev->devpath, sizeof(coredev->ir.phys));
> > -	strlcat(coredev->ir.phys, "/ir0", sizeof(coredev->ir.phys));
> > +	snprintf(coredev->ir.phys, sizeof(coredev->ir.phys),
> > +		 "%s/ir0", coredev->devpath);
> >  
> >  	dev->device_name = coredev->ir.name;
> >  	dev->input_phys = coredev->ir.phys;
> > -- 
> > 2.43.0
> > 
> >   
>