Re: [PATCH V3] usb: misc: ljca: Fix double free in error handling path

[Hans de Goede]

Hi,

On 3/11/24 1:57 PM, Yongzhi Liu wrote:
> When auxiliary_device_add() returns error and then calls
> auxiliary_device_uninit(), callback function ljca_auxdev_release
> calls kfree(auxdev->dev.platform_data) to free the parameter data
> of the function ljca_new_client_device. The callers of
> ljca_new_client_device shouldn't call kfree() again
> in the error handling path to free the platform data.
> 
> Fix this by cleaning up the redundant kfree() in all callers and
> adding kfree() the passed in platform_data on errors which happen
> before auxiliary_device_init() succeeds .
> 
> Fixes: acd6199f195d ("usb: Add support for Intel LJCA device")
> Signed-off-by: Yongzhi Liu <hyperlyzcs@xxxxxxxxx>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>

Regards,

Hans



> ---
>  drivers/usb/misc/usb-ljca.c | 22 +++++++++-------------
>  1 file changed, 9 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
> index 35770e608c64..2d30fc1be306 100644
> --- a/drivers/usb/misc/usb-ljca.c
> +++ b/drivers/usb/misc/usb-ljca.c
> @@ -518,8 +518,10 @@ static int ljca_new_client_device(struct ljca_adapter *adap, u8 type, u8 id,
>  	int ret;
>  
>  	client = kzalloc(sizeof *client, GFP_KERNEL);
> -	if (!client)
> +	if (!client) {
> +		kfree(data);
>  		return -ENOMEM;
> +	}
>  
>  	client->type = type;
>  	client->id = id;
> @@ -535,8 +537,10 @@ static int ljca_new_client_device(struct ljca_adapter *adap, u8 type, u8 id,
>  	auxdev->dev.release = ljca_auxdev_release;
>  
>  	ret = auxiliary_device_init(auxdev);
> -	if (ret)
> +	if (ret) {
> +		kfree(data);
>  		goto err_free;
> +	}
>  
>  	ljca_auxdev_acpi_bind(adap, auxdev, adr, id);
>  
> @@ -590,12 +594,8 @@ static int ljca_enumerate_gpio(struct ljca_adapter *adap)
>  		valid_pin[i] = get_unaligned_le32(&desc->bank_desc[i].valid_pins);
>  	bitmap_from_arr32(gpio_info->valid_pin_map, valid_pin, gpio_num);
>  
> -	ret = ljca_new_client_device(adap, LJCA_CLIENT_GPIO, 0, "ljca-gpio",
> +	return ljca_new_client_device(adap, LJCA_CLIENT_GPIO, 0, "ljca-gpio",
>  				     gpio_info, LJCA_GPIO_ACPI_ADR);
> -	if (ret)
> -		kfree(gpio_info);
> -
> -	return ret;
>  }
>  
>  static int ljca_enumerate_i2c(struct ljca_adapter *adap)
> @@ -629,10 +629,8 @@ static int ljca_enumerate_i2c(struct ljca_adapter *adap)
>  		ret = ljca_new_client_device(adap, LJCA_CLIENT_I2C, i,
>  					     "ljca-i2c", i2c_info,
>  					     LJCA_I2C1_ACPI_ADR + i);
> -		if (ret) {
> -			kfree(i2c_info);
> +		if (ret)
>  			return ret;
> -		}
>  	}
>  
>  	return 0;
> @@ -669,10 +667,8 @@ static int ljca_enumerate_spi(struct ljca_adapter *adap)
>  		ret = ljca_new_client_device(adap, LJCA_CLIENT_SPI, i,
>  					     "ljca-spi", spi_info,
>  					     LJCA_SPI1_ACPI_ADR + i);
> -		if (ret) {
> -			kfree(spi_info);
> +		if (ret)
>  			return ret;
> -		}
>  	}
>  
>  	return 0;