linux-kernel - Re: [PATCH 1/2] libnvdimm/security: 'security' attr never show 'overwrite' state

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Date:   Mon, 3 Aug 2020 13:41:21 -0700
From:   Dave Jiang <dave.jiang@...el.com>
To:     Jane Chu <jane.chu@...cle.com>, dan.j.williams@...el.com,
        vishal.l.verma@...el.com, ira.weiny@...el.com, jmoyer@...hat.com,
        linux-nvdimm@...ts.01.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] libnvdimm/security: 'security' attr never show
 'overwrite' state



On 7/24/2020 9:09 AM, Jane Chu wrote:
> Since
> commit d78c620a2e82 ("libnvdimm/security: Introduce a 'frozen' attribute"),
> when issue
>   # ndctl sanitize-dimm nmem0 --overwrite
> then immediately check the 'security' attribute,
>   # cat /sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/nmem0/security
>   unlocked
> Actually the attribute stays 'unlocked' through out the entire overwrite
> operation, never changed.  That's because 'nvdimm->sec.flags' is a bitmap
> that has both bits set indicating 'overwrite' and 'unlocked'.
> But security_show() checks the mutually exclusive bits before it checks
> the 'overwrite' bit at last. The order should be reversed.
> 
> The commit also has a typo: in one occasion, 'nvdimm->sec.ext_state'
> assignment is replaced with 'nvdimm->sec.flags' assignment for
> the NVDIMM_MASTER type.

May be best to split this fix to a different patch? Just thinking git bisect 
later on to track issues. Otherwise Reviewed-by: Dave Jiang <dave.jiang@...el.com>

> 
> Cc: Dan Williams <dan.j.williams@...el.com>
> Fixes: d78c620a2e82 ("libnvdimm/security: Introduce a 'frozen' attribute")
> Signed-off-by: Jane Chu <jane.chu@...cle.com>
> ---
>   drivers/nvdimm/dimm_devs.c | 4 ++--
>   drivers/nvdimm/security.c  | 2 +-
>   2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
> index b7b77e8..5d72026 100644
> --- a/drivers/nvdimm/dimm_devs.c
> +++ b/drivers/nvdimm/dimm_devs.c
> @@ -363,14 +363,14 @@ __weak ssize_t security_show(struct device *dev,
>   {
>   	struct nvdimm *nvdimm = to_nvdimm(dev);
>   
> +	if (test_bit(NVDIMM_SECURITY_OVERWRITE, &nvdimm->sec.flags))
> +		return sprintf(buf, "overwrite\n");
>   	if (test_bit(NVDIMM_SECURITY_DISABLED, &nvdimm->sec.flags))
>   		return sprintf(buf, "disabled\n");
>   	if (test_bit(NVDIMM_SECURITY_UNLOCKED, &nvdimm->sec.flags))
>   		return sprintf(buf, "unlocked\n");
>   	if (test_bit(NVDIMM_SECURITY_LOCKED, &nvdimm->sec.flags))
>   		return sprintf(buf, "locked\n");
> -	if (test_bit(NVDIMM_SECURITY_OVERWRITE, &nvdimm->sec.flags))
> -		return sprintf(buf, "overwrite\n");
>   	return -ENOTTY;
>   }
>   
> diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
> index 4cef69b..8f3971c 100644
> --- a/drivers/nvdimm/security.c
> +++ b/drivers/nvdimm/security.c
> @@ -457,7 +457,7 @@ void __nvdimm_security_overwrite_query(struct nvdimm *nvdimm)
>   	clear_bit(NDD_WORK_PENDING, &nvdimm->flags);
>   	put_device(&nvdimm->dev);
>   	nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
> -	nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
> +	nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
>   }
>   
>   void nvdimm_security_overwrite_query(struct work_struct *work)
>