Re: [PATCH v2] iio: multiplexer: fix unsigned check with less than zero

[Jonathan Cameron <jic23@kernel.org>]

On 08/03/17 13:28, Peter Rosin wrote:
> Comparing a size_t with less than zero is always false as size_t
> is unsigned. So, change the type of the variable to ssize_t and
> replicate the size check from mux_configure_channel() into
> mux_write_ext_info() thus ensuring that the size will fit in the
> ssize_t variable.
> 
> Detected by CoverityScan, CID#1415278 ("Unsigned compared against 0")
> 
> Reported-by: Colin Ian King <colin.king@canonical.com>
> Signed-off-by: Peter Rosin <peda@axentia.se>
For what it's worth, looks good to me.

Jonathan
> ---
>  drivers/iio/multiplexer/iio-mux.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> Hi!
> 
> Here's what intend to queue up.
> 
> Cheers,
> peda
> 
> diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c
> index 94d40f9b..bab9e69 100644
> --- a/drivers/iio/multiplexer/iio-mux.c
> +++ b/drivers/iio/multiplexer/iio-mux.c
> @@ -21,7 +21,7 @@
>  
>  struct mux_ext_info_cache {
>  	char *data;
> -	size_t size;
> +	ssize_t size;
>  };
>  
>  struct mux_child {
> @@ -206,6 +206,9 @@ static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private,
>  	char *new;
>  	ssize_t ret;
>  
> +	if (len >= PAGE_SIZE)
> +		return -EINVAL;
> +
>  	ret = iio_mux_select(mux, idx);
>  	if (ret < 0)
>  		return ret;
>