Re: [PATCH] scsi: ufs: core: Fix RPMB region size detection for UFS 2.2

[Bean Huo]

On Thu, 2026-01-29 at 11:38 +0400, Alexey Charkov wrote:
> +                       hba->dev_info.rpmb_region_size[0] =
> +                               get_unaligned_be64(desc_buf
> +                                       +
> RPMB_UNIT_DESC_PARAM_LOGICAL_BLK_COUNT)
> +                               <<
> desc_buf[RPMB_UNIT_DESC_PARAM_LOGICAL_BLK_SIZE]
> +                               >> 17; /* convert to 128 kBytes units */
> +               }
>         }

Hi Alexey, 

thanks for your fix, I didn't notice there is UFS 2.x on the market which will
use UFS OP-TEE RPMB framework.


here is potential u8 Overflow, since for the UFS3.x+, it is u8 in unit
descriptor, but                                                                
                                                                                                        

The calculation can overflow for larger RPMB regions (>32MB):                  
  - A u8 can only represent up to 255 × 128KB = ~32MB                          
  - The shift result is assigned directly without bounds checking


Kind regards,
Bean