On Mon, Jun 18, 2018 at 7:56 PM, Ben Hutchings
<ben.hutchings@xxxxxxxxxxxxxxx> wrote:
> 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@xxxxxxxxxxxxxxx> # 3.19+
> Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
> ---
> This is compile-tested only.
[adding KT in Cc]
We are currently testing the Lenovo P52, and this patch seems to
behave well. We have other issues with the P52, but unrelated to this
patch.
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Cheers,
Benjamin
>
> Ben.
>
> 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(-)
>
> diff --git a/drivers/input/mouse/elan_i2c.h b/drivers/input/mouse/elan_i2c.h
> index 599544c1a91c..243e0fa6e3e3 100644
> --- 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"
> diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c
> index 75e757520ef0..d5f74dd7e23b 100644
> --- a/drivers/input/mouse/elan_i2c_core.c
> +++ b/drivers/input/mouse/elan_i2c_core.c
> @@ -610,7 +610,7 @@ 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)
> diff --git a/drivers/input/mouse/elan_i2c_smbus.c b/drivers/input/mouse/elan_i2c_smbus.c
> index cfcb32559925..c060d270bc4d 100644
> --- 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 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]);
> --
> Ben Hutchings, Software Developer Codethink Ltd
> https://www.codethink.co.uk/ Dale House, 35 Dale Street
> Manchester, M1 2HF, United Kingdom
>
