From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 09 Sep 2014 12:05:28 +0000
Subject: [patch] [media] dvb: si21xx: buffer overflow in si21_writeregs()
Message-Id: <20140909120528.GA19760@mwanda>
List-Id: <kernel-janitors.vger.kernel.org>
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To: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org

"len" is user controlled and can be up to 255.  Anything more than 59
will cause a buffer overflow so we need to add a test for that.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/media/dvb-frontends/si21xx.c b/drivers/media/dvb-frontends/si21xx.c
index 73b47cc..16850e2 100644
--- a/drivers/media/dvb-frontends/si21xx.c
+++ b/drivers/media/dvb-frontends/si21xx.c
@@ -236,6 +236,9 @@ static int si21_writeregs(struct si21xx_state *state, u8 reg1,
 				.len = len + 1
 	};
 
+	if (len > sizeof(buf) - 1)
+		return -EINVAL;
+
 	msg.buf[0] =  reg1;
 	memcpy(msg.buf + 1, data, len);