[PATCH 3.16 221/370] i2c: fix kernel memory disclosure in dev interface

Ben Hutchings
2017-03-10T12:17:28Z

From: Vlad Tsyrklevich <vlad@tsyrklevich.net>

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: Ben Hutchings <ben@decadent.org.uk>
---
drivers/i2c/i2c-dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -334,7 +334,7 @@ static noinline int i2cdev_ioctl_smbus(s
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,