[Karmic][ [CVE-2010-4082] [PATCH 1/1] drivers/video/via/ioctl.c: prevent reading uninitialized stack memory, CVE-2010-4082

[Brad Figg]

From: Dan Rosenberg <drosenberg at vsecurity.com>

CVE-2010-4082

BugLink: http://bugs.launchpad.net/bugs/712744

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 at gmail.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat at gmx.de>

(cherry-picked from commit b4aaa78f4c2f9cde2f335b14f4ca30b01f9651ca)
Signed-off-by: Brad Figg <brad.figg at canonical.com>
---
 drivers/video/via/ioctl.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/video/via/ioctl.c b/drivers/video/via/ioctl.c
index da03c07..4d553d0 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;
 
-- 
1.7.3.5