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: <54ACA052.8010800@huawei.com>
Date:	Wed, 7 Jan 2015 10:56:18 +0800
From:	hujianyang <hujianyang@...wei.com>
To:	Seunghun Lee <waydi1@...il.com>
CC:	<miklos@...redi.hu>, <sedat.dilek@...il.com>,
	<richard.weinberger@...il.com>, <linux-fsdevel@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-unionfs@...r.kernel.org>
Subject: Re: [PATCH] ovl: Prevent rw remount when it should be ro mount

Hi,

There maybe some misunderstandings here. I think your patch really
fix an important problem, but not in correct way.

On 2015/1/6 22:02, Seunghun Lee wrote:
> 
> After patch:
> root@...ux86:~# mount -t overlay overlay -olowerdir=lower:lower2 merged
> mount: warning: merged seems to be mounted read-only.
> root@...ux86:~# mount | grep overlay
> overlay on /home/root/merged type overlay (ro,relatime,lowerdir=lower:lower2)
> root@...ux86:~# mount -o remount,rw merged
> mount: warning: /home/root/merged seems to be mounted read-only.
> root@...ux86:~# mount | grep overlay
> overlay on /home/root/merged type overlay (ro,relatime,lowerdir=lower:lower2)
> root@...ux86:~# echo hi > merged/hi
> -sh: merged/hi: Read-only file system
> root@...ux86:~#
> 

If users want a rw mount, can we give them a ro mount? I think it's
wrong, .remount_fs should refuse this request.

So I think your .remount_fs should check both what users in userpace
want and what kernel can offer, then realize legal requests and
refuse illegal requests. Not changing the requests from users.

Further more, can we replace upper/lower/work directories or mount
point by this .remount_fs?

If you want to export a new function, I think you should considering
more about these.

Thanks,
Hu

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ