[PATCH] s390: ensure NUL termination by strncpy()

[PATCH] s390: ensure NUL termination by strncpy()

[Roel Kluin]

For a larger source string, strncpy only NUL terminates when
the size argument is less than the size of the destination string.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
 arch/s390/kernel/ipl.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Is this maybe needed?

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 4890ac6..d52fcb4 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1881,7 +1881,7 @@ void __init setup_ipl(void)
 		break;
 	case IPL_TYPE_NSS:
 		strncpy(ipl_info.data.nss.name, kernel_nss_name,
-			sizeof(ipl_info.data.nss.name));
+			sizeof(ipl_info.data.nss.name) - 1);
 		break;
 	case IPL_TYPE_UNKNOWN:
 		/* We have no info to copy */

Re: [PATCH] s390: ensure NUL termination by strncpy()

[Heiko Carstens]

On Mon, Nov 16, 2009 at 07:53:54PM +0100, Roel Kluin wrote:
> For a larger source string, strncpy only NUL terminates when
> the size argument is less than the size of the destination string.
> 
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
>  arch/s390/kernel/ipl.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> Is this maybe needed?

No, kernel_nss_name as well as the data.nss.name char array within ipl_info
have the same size. So it will always fit and it is always NUL terminated.

Maybe it should be changed to a simple memcpy, like we have it at a second
place in the same file. I think that's up to Michael.

> diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
> index 4890ac6..d52fcb4 100644
> --- a/arch/s390/kernel/ipl.c
> +++ b/arch/s390/kernel/ipl.c
> @@ -1881,7 +1881,7 @@ void __init setup_ipl(void)
>  		break;
>  	case IPL_TYPE_NSS:
>  		strncpy(ipl_info.data.nss.name, kernel_nss_name,
> -			sizeof(ipl_info.data.nss.name));
> +			sizeof(ipl_info.data.nss.name) - 1);
>  		break;
>  	case IPL_TYPE_UNKNOWN:
>  		/* We have no info to copy */