agp: info leak in agpioc_info_wrap()

On 64 bit systems the agp_info struct has a 4 byte hole between
->agp_mode and ->aper_base.  We need to clear it to avoid disclosing
stack information to userspace.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
index 8121b4c..b297033 100644 (file)
--- a/drivers/char/agp/frontend.c
+++ b/drivers/char/agp/frontend.c
@@ -730,6 +730,7 @@ static int agpioc_info_wrap(struct agp_file_private *priv, void __user *arg)
 
        agp_copy_info(agp_bridge, &kerninfo);
 
+       memset(&userinfo, 0, sizeof(userinfo));
        userinfo.version.major = kerninfo.version.major;
        userinfo.version.minor = kerninfo.version.minor;
        userinfo.bridge_id = kerninfo.device->vendor |