From: Dan Rosenberg <drosenberg@vsecurity.com>
Date: Wed, 15 Sep 2010 21:44:22 +0000 (-0300)
Subject: V4L/DVB: ivtvfb: prevent reading uninitialized stack memory
X-Git-Tag: firefly_0821_release~7613^2~3803^2~7
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=405707985594169cfd0b1d97d29fcb4b4c6f2ac9;p=firefly-linux-kernel-4.4.55.git

V4L/DVB: ivtvfb: prevent reading uninitialized stack memory

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@gmail.com>
Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---

diff --git a/drivers/media/video/ivtv/ivtvfb.c b/drivers/media/video/ivtv/ivtvfb.c
index be03a712731c..f0316d02f09f 100644
--- a/drivers/media/video/ivtv/ivtvfb.c
+++ b/drivers/media/video/ivtv/ivtvfb.c
@@ -466,6 +466,8 @@ 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;