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Date:      Fri, 23 Feb 2018 17:46:10 +0100
From:      Ben RUBSON <ben.rubson@gmail.com>
To:        Warner Losh <imp@bsdimp.com>
Cc:        Freebsd fs <freebsd-fs@freebsd.org>, FreeBSD-scsi <freebsd-scsi@freebsd.org>
Subject:   Re: smartmontools and kern.securelevel
Message-ID:  <4C1D44AF-8247-4601-A39C-A8C0A5C8CBD8@gmail.com>
In-Reply-To: <CANCZdfo4PZv7ueCZUZ_bnPu26mL12HAUzfoszhXeDkrTShV6zA@mail.gmail.com>
References:  <0985ABD3-D141-4EE2-B1B3-3016B16E2B68@gmail.com> <CANCZdfo4PZv7ueCZUZ_bnPu26mL12HAUzfoszhXeDkrTShV6zA@mail.gmail.com>

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On 23 Feb 2018, Warner Losh wrote:

> On Fri, Feb 23, 2018 at 8:20 AM, Ben RUBSON <ben.rubson@gmail.com> wrote:
>
>> Hi,
>>
>> I run smartmontools on my storage servers, to launch periodic disk tests  
>> and alert on disk errors.
>>
>> Unfortunately, if we set sysctl kern.securelevel >=2, smartmontools does  
>> not work anymore.
>> Certainly because it needs to write directly to raw devices.
>> (details of the levels, -1 to 3, in security(7))
>>
>> Any workaround to this ?
>>
>> Perhaps we could think about allowing SMART commands to be written to  
>> disks when sysctl kern.securelevel >=2 ?
>> (I assume smartmontools writes SMART commands)
>
> Sending raw disks commands is inherently insecure. It's hard to create a  
> list of those commands that are OK because of the complexity and  
> diversity of the needed functionality. That complexity also makes it hard  
> to put the commands into a series of ioctls which could be made more  
> secure.

Thank you for your feedback Warner.

Can't all SMART commands be easily identified among the others ? (when a  
command arrives, does kernel sees it is SMART flagged ?)
Perhaps you assume some SMART commands may be dangerous for the disks' data  
itself ?

Thank you again,

Ben



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