[Karmic] [CVE-2010-4078] [PATCH 1/1] drivers/video/sis/sis_main.c: prevent reading uninitialized stack memory, CVE-2010-4078

[Stefan Bader]

On 01/25/2011 09:41 PM, Brad Figg wrote:
> From: Dan Rosenberg <drosenberg at vsecurity.com>
> 
> CVE-2010-4078
> 
> BugLink: http://bugs.launchpad.net/bugs/707579
> 
> Released by: 2.6.35.y stable upstream
>              2.6.32.y stable upstream
> 
> The FBIOGET_VBLANK device ioctl allows unprivileged users to read 16 bytes
> of uninitialized stack memory, because the "reserved" member of the
> fb_vblank struct declared on the stack is not altered or zeroed before
> being copied back to the user.  This patch takes care of it.
> 
> Signed-off-by: Dan Rosenberg <dan.j.rosenberg at gmail.com>
> Cc: Thomas Winischhofer <thomas at winischhofer.net>
> Cc: <stable at kernel.org>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
> 
> (cherry-picked from commit fd02db9de73faebc51240619c7c7f99bee9f65c7)
> Signed-off-by: Brad Figg <brad.figg at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>  drivers/video/sis/sis_main.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/video/sis/sis_main.c b/drivers/video/sis/sis_main.c
> index 559bf17..b52f8e4 100644
> --- a/drivers/video/sis/sis_main.c
> +++ b/drivers/video/sis/sis_main.c
> @@ -1701,6 +1701,9 @@ static int	sisfb_ioctl(struct fb_info *info, unsigned int cmd,
>  		break;
> 
>  	   case FBIOGET_VBLANK:
> +
> +		memset(&sisvbblank, 0, sizeof(struct fb_vblank));
> +
>  		sisvbblank.count = 0;
>  		sisvbblank.flags = sisfb_setupvbblankflags(ivideo, &sisvbblank.vcount, &sisvbblank.hcount);
>