Re: drivers/s390/char/keyboard.c kernel stack infoleak
From: Thomas Huth
Date: Fri Aug 04 2017 - 05:09:34 EST
Hi,
On 03.08.2017 15:59, sohu0106 wrote:
>
> The stack object "kbdiacr" has a total size of 4 bytes. Its last 1 bytes are padding bytes after "result" which are not initialized and leaked to userland via "copy_to_user".
>
>
> diff --git a/keyboard.c b/keyboard.c
> index ba0e4f9..76a6d35 100644
> --- a/keyboard.c
> +++ b/keyboard.c
> @@ -480,6 +480,8 @@ int kbd_ioctl(struct kbd_data *kbd, unsigned int cmd, unsigned long arg)
> struct kbdiacr diacr;
> int i;
>
> + memset( &diacr, 0, sizeof(struct kbdiacr) );
> +
I think it would be nicer to simply init the struct with "= {}"
directly, i.e.:
struct kbdiacr diacr = {};
And by the way, please have a look at the kernel patch submission
guidelines first, especially the COO part here:
https://www.kernel.org/doc/html/v4.12/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
So looking at your patch, please try to send plain text mails, and sign
your patch with a Signed-off-by line (i.e. no anonymous contributions).
Thanks!
Thomas