[PATCH 3.10 098/268] i2c: fix kernel memory disclosure in dev interface

From: Willy Tarreau
Date: Mon Jun 19 2017 - 14:55:31 EST


From: Vlad Tsyrklevich <vlad@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
drivers/i2c/i2c-dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index c3ccdea..fa3ecec 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,
--
2.8.0.rc2.1.gbe9624a