linux-kernel - [PATCH] video: fbdev: aty: do not leak uninitialized padding in clk to userspace

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Message-Id: <20170829135004.5739-1-vdronov@redhat.com>
Date:   Tue, 29 Aug 2017 15:50:04 +0200
From:   Vladis Dronov <vdronov@...hat.com>
To:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Vladis Dronov <vdronov@...hat.com>
Subject: [PATCH] video: fbdev: aty: do not leak uninitialized padding in clk to userspace

'clk' is copied to a userland with padding byte(s) after 'vclk_post_div'
field unitialized, leaking data from the stack. Fix this ensuring all of
'clk' is initialized to zero.

References: https://github.com/torvalds/linux/pull/441
Reported-by: sohu0106 <sohu0106@....com>
Signed-off-by: Vladis Dronov <vdronov@...hat.com>
---
 drivers/video/fbdev/aty/atyfb_base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index b55fdac..e4c91d7 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -1855,7 +1855,7 @@ static int atyfb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
 #if defined(DEBUG) && defined(CONFIG_FB_ATY_CT)
 	case ATYIO_CLKR:
 		if (M64_HAS(INTEGRATED)) {
-			struct atyclk clk;
+			struct atyclk clk = { 0 };
 			union aty_pll *pll = &par->pll;
 			u32 dsp_config = pll->ct.dsp_config;
 			u32 dsp_on_off = pll->ct.dsp_on_off;
-- 
2.9.5