Re: [PATCH V2] Fix buffer size warning for strcpy

["NeilBrown" <neilb@suse.de>]

On Thu, 19 Aug 2021, Nigel Croxon wrote:
> To meet requirements of Common Criteria certification vulnerability
> assessment. Static code analysis has been run and found the following
> error:
> buffer_size_warning: Calling "strncpy" with a maximum size
> argument of 16 bytes on destination array "ve->name" of
> size 16 bytes might leave the destination string unterminated.
> 
> The change is to make the destination size to fit the allocated size.

You really should explain here why we change from filling with spaces to
filling with nuls.

> 
> V2: Change from zero-terminated to zero-padded on memset and
> change from using strncpy to memcpy, feedback from Neil Brown.
> 
> Signed-off-by: Nigel Croxon <ncroxon@redhat.com>
> ---
>  super-ddf.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/super-ddf.c b/super-ddf.c
> index dc8e512..1771316 100644
> --- a/super-ddf.c
> +++ b/super-ddf.c
> @@ -2637,9 +2637,13 @@ static int init_super_ddf_bvd(struct supertype *st,
>  		ve->init_state = DDF_init_not;
>  
>  	memset(ve->pad1, 0xff, 14);
> -	memset(ve->name, ' ', 16);
> -	if (name)
> -		strncpy(ve->name, name, 16);
> +	memset(ve->name, '\0', sizeof(ve->name));
> +	if (name) {
> +		int l = strlen(ve->name);
> +		if (l > 16)
> +			l = 16;
> +		memcpy(ve->name, name, l);
> +	}

Reviewed-by: NeilBrown <neilb@suse.de>

Thanks,
NeilBrown

>  	ddf->virt->populated_vdes =
>  		cpu_to_be16(be16_to_cpu(ddf->virt->populated_vdes)+1);
>  
> -- 
> 2.29.2
> 
>