linux-kernel - Re: [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e4430207-7def-8776-0289-0d58689dc0cd@grimberg.me>
Date:   Thu, 22 Aug 2019 12:17:39 -0700
From:   Sagi Grimberg <sagi@...mberg.me>
To:     Max Gurtovoy <maxg@...lanox.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org,
        linux-block@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc:     Chaitanya Kulkarni <Chaitanya.Kulkarni@....com>,
        Stephen Bates <sbates@...thlin.com>, Jens Axboe <axboe@...com>,
        Keith Busch <kbusch@...nel.org>, Christoph Hellwig <hch@....de>
Subject: Re: [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl


>>>> I don't understand why we don't limit a regular ctrl to single 
>>>> access and we do it for the PT ctrl.
>>>>
>>>> I guess the block layer helps to sync between multiple access in 
>>>> parallel but we can do it as well.
>>>>
>>>> Also, let's say you limit the access to this subsystem to 1 user, 
>>>> the bdev is still accessibly for local user and also you can create 
>>>> a different subsystem that will use this device (PT and non-PT ctrl).
>>>>
>>>> Sagi,
>>>>
>>>> can you explain the trouble you meant and how this limitation solve 
>>>> it ?
>>>
>>> Its different to emulate the controller with all its admin
>>> commands vs. passing it through to the nvme device.. (think of format 
>>> nvm)
>>>
>>>
>>>
>> we don't need to support format command for PT ctrl as we don't 
>> support other commands such create_sq/cq.
> 
> That is just an example, basically every command that we are not aware
> of we simply passthru to the drive without knowing the implications
> on a multi-host environment..

If we were to change the logic of nvmet_parse_passthru_admin_cmd to
have the default case do nvmet_parse_admin_cmd, and only have
the vendor-specific space opcodes do nvmet_passthru_execute_cmd
then I could not see at the moment how we can break a multi-host
export...