Re: [PATCH v2 1/2] scsi: ufs: core: Remove unnecessary if statement

[Bean Huo]

On Fri, 2022-10-14 at 11:37 -0700, Bart Van Assche wrote:
> >                 pr_err("Max General LU supported by UFS isn't
> > initialized\n");
> >                 return false;
> >         }
> > -       /* WB is available only for the logical unit from 0 to 7 */
> > -       if (param_offset == UNIT_DESC_PARAM_WB_BUF_ALLOC_UNITS)
> > -               return lun < UFS_UPIU_MAX_WB_LUN_ID;
> >         return lun == UFS_UPIU_RPMB_WLUN || (lun < dev_info-
> > >max_lu_supported);
> >    }
> 
> Hi Bean,
> 
> I think the above patch reintroduces the stack overflow issue fixed
> by
> commit a2fca52ee640 ("scsi: ufs: WB is only available on LUN #0 to
> #7").
> 
> How about reverting commit a2fca52ee640 and fixing the stack overflow
> issue in another way than by modifying ufs_is_valid_unit_desc_lun()?
> 
> Thanks,
> 
> Bart.

Hi Bart, 

I double-checked the changelog and the stack overflow issue was double
fixed by your commit:

commit d3d9c4570285 ("scsi: ufs: Fix memory corruption by
ufshcd_read_desc_param()"),


For example, if the user wants to read wb_buf_alloc_units in the RPMB
unit descriptor,

parameter offset = 41, parameter size = 4,
buff_len = 45;

After ufshcd_query_descriptor_retry(), buff_len will be updated to 35.

param_offset > buff_len, then -EINVAL will be returned.

So we can safely remove this check, and if you still have concerns, I
can verify when I get back to the office.

Kind regards,
Bean