RE: [PATCH 1/2] scsi: Fix get_user() in call sg_scsi_ioctl()

[David Laight]

From: Kirill A. Shutemov
> Sent: 16 November 2022 00:44
> 
> get_user() expects the pointer to be pointer-to-simple-variable type,
> but sic->data is array of 'unsigned char'. It violates get_user()
> contracts.
> 
> Cast it explicitly to 'unsigned char __user *'. It matches current
> behaviour.
> 
> This is preparation for fixing sparse warnings caused by Linear Address
> Masking patchset.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxx>
> Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
> ---
>  drivers/scsi/scsi_ioctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
> index 2d20da55fb64..72b3ab5137b8 100644
> --- a/drivers/scsi/scsi_ioctl.c
> +++ b/drivers/scsi/scsi_ioctl.c
> @@ -519,7 +519,7 @@ static int sg_scsi_ioctl(struct request_queue *q, fmode_t mode,
>  		return -EFAULT;
>  	if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
>  		return -EINVAL;
> -	if (get_user(opcode, sic->data))
> +	if (get_user(opcode, (unsigned char __user *)sic->data))

Using &sic->data[0] should work and is much nicer than the cast.

	David

>  		return -EFAULT;
> 
>  	bytes = max(in_len, out_len);
> --
> 2.38.0

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)