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

Tim Gardner tim.gardner at canonical.com
Tue Jan 25 21:17:57 UTC 2011


On 01/25/2011 01:42 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>
> ---
>   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);
>

Acked-by: Tim Gardner <tim.gardner at canonical.com>

-- 
Tim Gardner tim.gardner at canonical.com




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