linux-kernel - Re: Can initramfs be mounted read-only?

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]

Date:	Wed, 12 Aug 2009 22:24:16 +0100
From:	Alan Jenkins <sourcejedi.lkml@...glemail.com>
To:	David Wuertele <dave+gmane@...rtele.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Can initramfs be mounted read-only?

On 8/12/09, David Wuertele <dave+gmane@...rtele.com> wrote:
> I've been trying to create a system with a read-only rootfs using initramfs,
> but I'm not having any luck.  I've included "ro" on my command line and when
> I cat /proc/cmdline it reports "ro" like I expect.  But when I type "mount",
> I see this:
>
>   rootfs on / type rootfs (rw)

Changing this could potentially break a lot of systems.  At least
Debian has "ro" as a default boot option, and it uses an initramfs by
default.

> And I can create new files and write to them just fine.  Is it possible to
> mount an initramfs read-only?
>
> The documentation for early userspace and initramfs does not talk about
> read/write permissions.

Have you tried running "mount / -oremount,ro" in an init script?

Regards
Alan
--
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/