Re: [PATCH v2 1/4] HID: i2c-hid: fix memory corruption due to missing hid declaration

[Jean Delvare <khali@linux-fr.org>]

On Wed,  5 Dec 2012 15:02:53 +0100, Benjamin Tissoires wrote:
> HID descriptors contains 4 bytes of reserved field.
> The previous implementation was overriding the next fields in struct i2c_hid.
> 
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
> ---
>  drivers/hid/i2c-hid/i2c-hid.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 7062df2..34cca42 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -69,6 +69,7 @@ struct i2c_hid_desc {
>  	__le16 wVendorID;
>  	__le16 wProductID;
>  	__le16 wVersionID;
> +	__le32 reserved;
>  } __packed;
>  
>  struct i2c_hid_cmd {
> @@ -776,7 +777,13 @@ static int __devinit i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
>  	}
>  
>  	dsize = le16_to_cpu(hdesc->wHIDDescLength);
> -	if (!dsize || dsize > HID_MAX_DESCRIPTOR_SIZE) {
> +	/*
> +	 * the size of the HID descriptor should at least contain
> +	 * its size and the bcdVersion (4 bytes), and should not be greater
> +	 * than sizeof(struct i2c_hid_desc) as we directly fill this struct
> +	 * through i2c_hid_command.
> +	 */
> +	if (dsize < 4 || dsize > sizeof(struct i2c_hid_desc)) {
>  		dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
>  			dsize);
>  		return -ENODEV;

Reviewed-by: Jean Delvare <khali@linux-fr.org>

-- 
Jean Delvare