re: Input: add driver for Elan I2C/SMbus touchpad

re: Input: add driver for Elan I2C/SMbus touchpad

[Dan Carpenter]

Hello Duson Lin,

The patch 29fbd64b0fd2: "Input: add driver for Elan I2C/SMbus
touchpad" from Oct 3, 2014, leads to the following static checker
warning:

	drivers/input/mouse/elan_i2c_smbus.c:372 elan_smbus_prepare_fw_update()
	warn: sizeof(NUMBER)?

drivers/input/mouse/elan_i2c_smbus.c
   365                  /*
   366                   * Read back password to make sure we enabled flash
   367                   * successfully.
   368                   */
   369                  len = i2c_smbus_read_block_data(client,
   370                                                  ETP_SMBUS_IAP_PASSWORD_READ,
   371                                                  val);
   372                  if (len != sizeof(ETP_SMBUS_IAP_PASSWORD)) {
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
sizeof(int) is 4.
val is a 3 byte array.
If we read 4 bytes then we are writing beyond the end of the val[]
array.

   373                          error = len < 0 ? len : -EIO;
   374                          dev_err(dev, "failed to read iap password: %d\n",
   375                                  error);
   376                          return error;
   377                  }
   378  
   379                  password = be16_to_cpup((__be16 *)val);
   380                  if (password != ETP_SMBUS_IAP_PASSWORD) {
   381                          dev_err(dev, "wrong iap password = 0x%X\n", password);
   382                          return -EIO;
   383                  }

regards,
dan carpenter

Re: Input: add driver for Elan I2C/SMbus touchpad

[Dmitry Torokhov]

Hi Dan,

On Thu, Oct 23, 2014 at 05:58:13PM +0300, Dan Carpenter wrote:
> Hello Duson Lin,
> 
> The patch 29fbd64b0fd2: "Input: add driver for Elan I2C/SMbus
> touchpad" from Oct 3, 2014, leads to the following static checker
> warning:

Can you copy committer on such reports as well please?

> 
> 	drivers/input/mouse/elan_i2c_smbus.c:372 elan_smbus_prepare_fw_update()
> 	warn: sizeof(NUMBER)?
> 
> drivers/input/mouse/elan_i2c_smbus.c
>    365                  /*
>    366                   * Read back password to make sure we enabled flash
>    367                   * successfully.
>    368                   */
>    369                  len = i2c_smbus_read_block_data(client,
>    370                                                  ETP_SMBUS_IAP_PASSWORD_READ,
>    371                                                  val);
>    372                  if (len != sizeof(ETP_SMBUS_IAP_PASSWORD)) {
>                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> sizeof(int) is 4.
> val is a 3 byte array.
> If we read 4 bytes then we are writing beyond the end of the val[]
> array.

We should be checking sizeof(u16) here, I'll fix it up.

Thanks.

-- 
Dmitry