Re: [PATCH] scsi: mpt2sas: mpt2sas_base.c: Cleaning up missing null-terminate after strncpy call

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Wed, 2014-06-04 at 23:36 +0200, Rickard Strandqvist wrote:
> Added a guaranteed null-terminate after call to strncpy.
> 
> This was partly found using a static code analysis program called cppcheck.
> 
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
>  drivers/scsi/mpt2sas/mpt2sas_base.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.c b/drivers/scsi/mpt2sas/mpt2sas_base.c
> index bde63f7..4c3eceb 100644
> --- a/drivers/scsi/mpt2sas/mpt2sas_base.c
> +++ b/drivers/scsi/mpt2sas/mpt2sas_base.c
> @@ -2097,7 +2097,8 @@ _base_display_ioc_capabilities(struct MPT2SAS_ADAPTER *ioc)
>  	u32 bios_version;
>  
>  	bios_version = le32_to_cpu(ioc->bios_pg3.BiosVersion);
> -	strncpy(desc, ioc->manu_pg0.ChipName, 16);
> +	strncpy(desc, ioc->manu_pg0.ChipName, sizeof(desc));
> +	desc[sizeof(desc) - 1] = '\0';

There's no bug here because the specs define the ChipName field of the
manufacturing page 0 to be 16 bytes and null terminated.  The nasty part
is the way this driver is littered with magic numbers.

James