lkml.org 
[lkml]   [2018]   [Jul]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.9 094/101] Input: elan_i2c_smbus - fix more potential stack buffer overflows
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben.hutchings@codethink.co.uk>

commit 50fc7b61959af4b95fafce7fe5dd565199e0b61a upstream.

Commit 40f7090bb1b4 ("Input: elan_i2c_smbus - fix corrupted stack")
fixed most of the functions using i2c_smbus_read_block_data() to
allocate a buffer with the maximum block size. However three
functions were left unchanged:

* In elan_smbus_initialize(), increase the buffer size in the same
way.
* In elan_smbus_calibrate_result(), the buffer is provided by the
caller (calibrate_store()), so introduce a bounce buffer. Also
name the result buffer size.
* In elan_smbus_get_report(), the buffer is provided by the caller
but happens to be the right length. Add a compile-time assertion
to ensure this remains the case.

Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/input/mouse/elan_i2c.h | 2 ++
drivers/input/mouse/elan_i2c_core.c | 2 +-
drivers/input/mouse/elan_i2c_smbus.c | 10 ++++++++--
3 files changed, 11 insertions(+), 3 deletions(-)

--- a/drivers/input/mouse/elan_i2c.h
+++ b/drivers/input/mouse/elan_i2c.h
@@ -27,6 +27,8 @@
#define ETP_DISABLE_POWER 0x0001
#define ETP_PRESSURE_OFFSET 25

+#define ETP_CALIBRATE_MAX_LEN 3
+
/* IAP Firmware handling */
#define ETP_PRODUCT_ID_FORMAT_STRING "%d.0"
#define ETP_FW_NAME "elan_i2c_" ETP_PRODUCT_ID_FORMAT_STRING ".bin"
--- a/drivers/input/mouse/elan_i2c_core.c
+++ b/drivers/input/mouse/elan_i2c_core.c
@@ -595,7 +595,7 @@ static ssize_t calibrate_store(struct de
int tries = 20;
int retval;
int error;
- u8 val[3];
+ u8 val[ETP_CALIBRATE_MAX_LEN];

retval = mutex_lock_interruptible(&data->sysfs_mutex);
if (retval)
--- a/drivers/input/mouse/elan_i2c_smbus.c
+++ b/drivers/input/mouse/elan_i2c_smbus.c
@@ -56,7 +56,7 @@
static int elan_smbus_initialize(struct i2c_client *client)
{
u8 check[ETP_SMBUS_HELLOPACKET_LEN] = { 0x55, 0x55, 0x55, 0x55, 0x55 };
- u8 values[ETP_SMBUS_HELLOPACKET_LEN] = { 0, 0, 0, 0, 0 };
+ u8 values[I2C_SMBUS_BLOCK_MAX] = {0};
int len, error;

/* Get hello packet */
@@ -117,12 +117,16 @@ static int elan_smbus_calibrate(struct i
static int elan_smbus_calibrate_result(struct i2c_client *client, u8 *val)
{
int error;
+ u8 buf[I2C_SMBUS_BLOCK_MAX] = {0};
+
+ BUILD_BUG_ON(ETP_CALIBRATE_MAX_LEN > sizeof(buf));

error = i2c_smbus_read_block_data(client,
- ETP_SMBUS_CALIBRATE_QUERY, val);
+ ETP_SMBUS_CALIBRATE_QUERY, buf);
if (error < 0)
return error;

+ memcpy(val, buf, ETP_CALIBRATE_MAX_LEN);
return 0;
}

@@ -470,6 +474,8 @@ static int elan_smbus_get_report(struct
{
int len;

+ BUILD_BUG_ON(I2C_SMBUS_BLOCK_MAX > ETP_SMBUS_REPORT_LEN);
+
len = i2c_smbus_read_block_data(client,
ETP_SMBUS_PACKET_QUERY,
&report[ETP_SMBUS_REPORT_OFFSET]);

\
 
 \ /
  Last update: 2018-07-01 20:08    [W:0.346 / U:0.948 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site