Re: [PATCH] HID: uhid: convert to hid_safe_input_report()

[Lee Jones <lee@kernel.org>]

On Sat, 06 Jun 2026, Carlos Llamas wrote:

> Commit 0a3fe972a7cb ("HID: core: Mitigate potential OOB by removing
> bogus memset()"), added a check in hid_report_raw_event() to reject
> reports if the received data size is smaller than expected. This was
> intended to prevent OOB errors by no longer allowing zeroing-out of
> shorter reports due to the lack of buffer size information.
> 
> However, this leads to regressions in hid_report_raw_event(), where
> shorter than expected reports are rejected, even though their buffers
> are sufficiently large to be zero-padded.
> 
> To solve this issue, Benjamin introduced a safer alternative in commit
> 206342541fc8 ("HID: core: introduce hid_safe_input_report()"), which
> forwards the buffer size and allows hid_report_raw_event() to safely
> zero-pad the data.
> 
> Convert uhid to use hid_safe_input_report() and pass UHID_DATA_MAX as
> the buffer size. This prevents the reported regressions [1], allowing
> hid core to zero-pad the shorter reports safely as expected.
> 
> Cc: stable@vger.kernel.org
> Fixes: 0a3fe972a7cb ("HID: core: Mitigate potential OOB by removing bogus memset()")
> Closes: https://lore.kernel.org/all/ahsh0UtTX6e0ZeHa@google.com/ [1]
> Signed-off-by: Carlos Llamas <cmllamas@google.com>

Reviewed-by: Lee Jones <lee@kernel.org>

> ---
>  drivers/hid/uhid.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
> index 524b53a3c87b..37b60c3aaf66 100644
> --- a/drivers/hid/uhid.c
> +++ b/drivers/hid/uhid.c
> @@ -595,8 +595,8 @@ static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
>  	if (!READ_ONCE(uhid->running))
>  		return -EINVAL;
>  
> -	hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
> -			 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
> +	hid_safe_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data, UHID_DATA_MAX,
> +			      min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
>  
>  	return 0;
>  }
> @@ -606,8 +606,8 @@ static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
>  	if (!READ_ONCE(uhid->running))
>  		return -EINVAL;
>  
> -	hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
> -			 min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
> +	hid_safe_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data, UHID_DATA_MAX,
> +			      min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
>  
>  	return 0;
>  }
> -- 
> 2.54.0.1032.g2f8565e1d1-goog
> 

-- 
Lee Jones