linux-kernel - Re: [PATCH 2/2] blk-zoned: allow BLKREPORTZONE without CAP_SYS

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Date:   Thu, 3 Jun 2021 10:00:08 +0000
From:   Damien Le Moal <Damien.LeMoal@....com>
To:     "dsterba@...e.cz" <dsterba@...e.cz>,
        Niklas Cassel <Niklas.Cassel@....com>
CC:     Jens Axboe <axboe@...nel.dk>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMIN

On 2021/06/03 18:54, David Sterba wrote:
> On Mon, May 31, 2021 at 01:54:53PM +0000, Niklas Cassel wrote:
>> From: Niklas Cassel <niklas.cassel@....com>
>>
>> Performing a BLKREPORTZONE operation should be allowed under the same
>> permissions as read(). (read() does not require CAP_SYS_ADMIN).
>>
>> Remove the CAP_SYS_ADMIN requirement, and instead check that the fd was
>> successfully opened with FMODE_READ. This way BLKREPORTZONE will match
>> the access control requirement of read().
> 
> Does this mean that a process that does not have read nor write access
> to the device itself (blocks) is capable of reading the zone
> information? Eg. some monitoring tool.

With this change, to do a report zones, the process will only need to have read
access to the device. And if it has read access, it also means that it can read
the zones content.


-- 
Damien Le Moal
Western Digital Research