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

Jean Delvare
2012-12-05T17:25:43Z

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