Re: [PATCH v4] hwmon: (aquacomputer_d5next) valid the data size before reading the sensor data

[Greg KH]

On Sat, Aug 22, 2026 at 07:34:35PM +0800, Edward Adam Davis wrote:
> The user-forged sensor data is only 65 bytes long; however, aqc_raw_event()
> fails to handle cases where the sensor data length is too small when reading
> the data, resulting in [1] during the read process.

What is "user-forged sensor data"?

> 
> Add a data size check, if the size is less than that required for the
> specific data item to be read, abort the sensor data read operation.

This patch does much more than that.

> 
> [1]
> BUG: KASAN: slab-out-of-bounds in aqc_raw_event+0x213e/0x25d0 drivers/hwmon/aquacomputer_d5next.c:1327
> Read of size 2 at addr ffff888108aba257 by task swapper/1/0
> Call Trace:
>  get_unaligned_be16 include/linux/unaligned.h:48 [inline]
>  aqc_raw_event drivers/hwmon/aquacomputer_d5next.c:1345 [inline]
>  aqc_raw_event+0x213e/0x25d0 drivers/hwmon/aquacomputer_d5next.c:1327
>  __hid_input_report.constprop.0+0x319/0x470 drivers/hid/hid-core.c:2168
>  hid_irq_in+0x55d/0x710 drivers/hid/usbhid/hid-core.c:287
>  __usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657
>  usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741
> 
> Fixes: 0e35f63f7f4e ("hwmon: add driver for Aquacomputer D5 Next")
> Reported-by: syzbot+9ee5f5dc18673d6b2f37@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=9ee5f5dc18673d6b2f37
> Tested-by: syzbot+9ee5f5dc18673d6b2f37@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
> ---

Was the Assisted-by: tag forgotten?


> v1 -> v2: change to check the data item and update comments
> v2 -> v3: check all sub items and update subject
> v3 -> v4: add speed and flow check
> 
>  drivers/hwmon/aquacomputer_d5next.c | 104 ++++++++++++++++++++++++++++
>  1 file changed, 104 insertions(+)
> 
> diff --git a/drivers/hwmon/aquacomputer_d5next.c b/drivers/hwmon/aquacomputer_d5next.c
> index 1ca70e726298..89c9fc0c77e5 100644
> --- a/drivers/hwmon/aquacomputer_d5next.c
> +++ b/drivers/hwmon/aquacomputer_d5next.c
> @@ -1324,6 +1324,107 @@ static const struct hwmon_chip_info aqc_chip_info = {
>  	.info = aqc_info,
>  };
>  
> +/* aqc_raw_data_valid()
> + * Does not support special-case sensor readings data size check

Why not?

> + */
> +static bool aqc_raw_data_valid(struct aqc_data *priv, int size)
> +{
> +	int off, fan_off, i;
> +	char *msg;
> +
> +	if (!priv)
> +		return false;
> +
> +	/* +1 for get_unaligned_be16(), it reads 2 bytes */
> +	off = priv->serial_number_start_offset + SERIAL_PART_OFFSET + 1;
> +	if (off >= size) {
> +		msg = "serial number start offset";

That's a lot of debugging code being added, why?  Who is going to use
that?



> +		goto invalid;
> +	}
> +
> +	off = priv->firmware_version_offset + 1;
> +	if (off >= size) {
> +		msg = "firmware version offset";
> +		goto invalid;
> +	}
> +
> +	/* Physical temperature sensor readings data size check*/
> +	for (i = 0; i < priv->num_temp_sensors; i++) {
> +		off = priv->temp_sensor_start_offset + i * AQC_SENSOR_SIZE + 1;
> +
> +		if (off >= size) {
> +			msg = "temp sensor start offset";
> +			goto invalid;
> +		}
> +	}
> +
> +	/* Virtual temperature sensor readings data size check*/
> +	for (i = 0; i < priv->num_virtual_temp_sensors; i++) {
> +		off = priv->virtual_temp_sensor_start_offset +
> +		      i * AQC_SENSOR_SIZE + 1;
> +
> +		if (off >= size) {
> +			msg = "virtual temp sensor start offset";
> +			goto invalid;
> +		}
> +	}
> +
> +	/* Fan speed and related readings data size check */
> +	if (!priv->fan_structure)
> +		goto flow;
> +
> +	for (i = 0; i < priv->num_fans; i++) {
> +		fan_off = priv->fan_sensor_offsets[i] + 1;
> +		off = fan_off + priv->fan_structure->speed;
> +		if (off >= size) {
> +			msg = "fan speed offset";
> +			goto invalid;
> +		}
> +
> +		off = fan_off + priv->fan_structure->power;
> +		if (off >= size) {
> +			msg = "fan power offset";
> +			goto invalid;
> +		}
> +
> +		off = fan_off + priv->fan_structure->voltage;
> +		if (off >= size) {
> +			msg = "fan voltage offset";
> +			goto invalid;
> +		}
> +
> +		off = fan_off + priv->fan_structure->curr;
> +		if (off >= size) {
> +			msg = "fan curr offset";
> +			goto invalid;
> +		}
> +	}
> +
> +flow:
> +	/* Flow sensor readings data size check */
> +	for (i = 0; i < priv->num_flow_sensors; i++) {
> +		off = priv->flow_sensors_start_offset + i * AQC_SENSOR_SIZE + 1;
> +		if (off >= size) {
> +			msg = "flow sensors start offset";
> +			goto invalid;
> +		}
> +	}
> +
> +	if (priv->power_cycle_count_offset != 0) {
> +		off = priv->power_cycle_count_offset + 3;
> +		if (off >= size) {
> +			msg = "power cycle count offset";
> +			goto invalid;
> +		}
> +	}
> +
> +	return true;
> +invalid:
> +	pr_debug("data size (%d) is less than the %s, %s\n",
> +		 size, msg, __func__);

drivers should always use dev_dbg().

also pr_debug() already has __func__ in it.  Please fix your LLM.

thanks,

greg k-h