[Karmic] [CVE-2010-4079] [PATCH 1/1] V4L/DVB: ivtvfb: prevent reading uninitialized stack memory, CVE-2010-4079

[Stefan Bader]

On 01/26/2011 03:12 AM, Brad Figg wrote:
> From: Dan Rosenberg <drosenberg at vsecurity.com>
> 
> CVE-2010-4079
> 
> BugLink: http://bugs.launchpad.net/bugs/707649
> 
> Released by: 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>
> Signed-off-by: Andy Walls <awalls at md.metrocast.net>
> Signed-off-by: Mauro Carvalho Chehab <mchehab at redhat.com>
> 
> (cherry-picked from commit 405707985594169cfd0b1d97d29fcb4b4c6f2ac9)
> Signed-off-by: Brad Figg <brad.figg at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>  drivers/media/video/ivtv/ivtvfb.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/media/video/ivtv/ivtvfb.c b/drivers/media/video/ivtv/ivtvfb.c
> index fa6bb85..6b61bb6 100644
> --- a/drivers/media/video/ivtv/ivtvfb.c
> +++ b/drivers/media/video/ivtv/ivtvfb.c
> @@ -457,6 +457,8 @@ static int ivtvfb_ioctl(struct fb_info *info, unsigned int cmd, unsigned long ar
>  			struct fb_vblank vblank;
>  			u32 trace;
>  
> +			memset(&vblank, 0, sizeof(struct fb_vblank));
> +
>  			vblank.flags = FB_VBLANK_HAVE_COUNT |FB_VBLANK_HAVE_VCOUNT |
>  					FB_VBLANK_HAVE_VSYNC;
>  			trace = read_reg(0x028c0) >> 16;