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

[Brad Figg]

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>
---
 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 9ff3425..4559a0a 100644
--- a/drivers/media/video/ivtv/ivtvfb.c
+++ b/drivers/media/video/ivtv/ivtvfb.c
@@ -458,6 +458,8 @@ 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(IVTV_REG_DEC_LINE_FIELD) >> 16;
-- 
1.7.0.4