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Input: elan_i2c_smbus - fix more potential stack buffer overflows

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Commit 40f7090bb1 ("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>
This commit is contained in:
Ben Hutchings 2018-06-19 11:17:32 -07:00 committed by Dmitry Torokhov
parent 8938fc7b8f
commit 50fc7b6195
3 changed files with 11 additions and 3 deletions
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2
drivers/input/mouse/elan_i2c.h
View File

@ -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"

2
drivers/input/mouse/elan_i2c_core.c
View File

@ -613,7 +613,7 @@ static ssize_t calibrate_store(struct device *dev,
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)

10
drivers/input/mouse/elan_i2c_smbus.c
View File

@ -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 i2c_client *client)
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;
}
@ -472,6 +476,8 @@ static int elan_smbus_get_report(struct i2c_client *client, u8 *report)
{
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]);