From: Vlad Tsyrklevich <vlad@tsyrklevich.net>
Date: Mon, 9 Jan 2017 15:53:36 +0000 (+0700)
Subject: i2c: fix kernel memory disclosure in dev interface
X-Git-Tag: v3.12.70~75
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=142088b084b05f9cfe68ee3e433e738016e3c0e5;p=thirdparty%2Fkernel%2Fstable.git

i2c: fix kernel memory disclosure in dev interface

commit 30f939feaeee23e21391cfc7b484f012eb189c3c upstream.

i2c_smbus_xfer() does not always fill an entire block, allowing
kernel stack memory disclosure through the temp variable. Clear
it before it's read to.

Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index c3ccdea3d1805..fa3ecec524fa4 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -328,7 +328,7 @@ static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
 		unsigned long arg)
 {
 	struct i2c_smbus_ioctl_data data_arg;
-	union i2c_smbus_data temp;
+	union i2c_smbus_data temp = {};
 	int datasize, res;
 
 	if (copy_from_user(&data_arg,