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Subject: Re: [PATCH] Revert "zram: convert remaining CLASS_ATTR() to
 CLASS_ATTR_RO()"
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Minchan Kim <minchan@kernel.org>,
        Nitin Gupta <ngupta@vflare.org>
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        Wade Mealing <wmealing@redhat.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Jens Axboe <axboe@kernel.dk>
References: <20200617103412.GA2027053@kroah.com>
From:   Steffen Maier <maier@linux.ibm.com>
Message-ID: <5cde1d94-275e-2555-b13d-0b04a7a70fc7@linux.ibm.com>
Date:   Wed, 17 Jun 2020 13:05:54 +0200
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On 6/17/20 12:34 PM, Greg Kroah-Hartman wrote:
> From: Wade Mealing <wmealing@redhat.com>
> 
> Turns out that the permissions for 0400 really are what we want here,
> otherwise any user can write to this file.

Minor confusion on my side:
Did you mean "read from" instead of "write to"?
I.e. only owner may read but not group nor others.
Whereas using CLASS_ATTR_RO would resolve into 0444.

> 
> [fixed formatting and made static - gregkh]
> 
> Reported-by: Wade Mealing <wmealing@redhat.com>
> Cc: stable <stable@vger.kernel.org>
> Fixes: f40609d1591f ("zram: convert remaining CLASS_ATTR() to CLASS_ATTR_RO()")
> Link: https://bugzilla.redhat.com/show_bug.cgi?id=1847832
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>   drivers/block/zram/zram_drv.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 6e2ad90b17a3..270dd810be54 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -2021,7 +2021,8 @@ static ssize_t hot_add_show(struct class *class,
>   		return ret;
>   	return scnprintf(buf, PAGE_SIZE, "%d\n", ret);
>   }
> -static CLASS_ATTR_RO(hot_add);
> +static struct class_attribute class_attr_hot_add =
> +	__ATTR(hot_add, 0400, hot_add_show, NULL);
> 
>   static ssize_t hot_remove_store(struct class *class,
>   			struct class_attribute *attr,
> 


-- 
Mit freundlichen Gruessen / Kind regards
Steffen Maier

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