drivers/video/via/ioctl.c: prevent reading uninitialized stack memory

The VIAFB_GET_INFO device ioctl allows unprivileged users to read 246
bytes of uninitialized stack memory, because the "reserved" member of
the viafb_ioctl_info 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@gmail.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/video/via/ioctl.c b/drivers/video/via/ioctl.c
index da03c074e32a..4d553d0b8d7a 100644
--- a/drivers/video/via/ioctl.c
+++ b/drivers/video/via/ioctl.c
@@ -25,6 +25,8 @@ int viafb_ioctl_get_viafb_info(u_long arg)
 {
         struct viafb_ioctl_info viainfo;
 
+        memset(&viainfo, 0, sizeof(struct viafb_ioctl_info));
+
         viainfo.viafb_id = VIAID;
         viainfo.vendor_id = PCI_VIA_VENDOR_ID;