linux-kernel - Re: [RFC][PATCH] procfs: add privacy options

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: <44C547B0.1090304@lsrfire.ath.cx>
Date:	Tue, 25 Jul 2006 00:20:32 +0200
From:	Rene Scharfe <rene.scharfe@...fire.ath.cx>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	linux-kernel mailing list <linux-kernel@...r.kernel.org>,
	Andrew Morton OSDL <akpm@...l.org>,
	Albert Cahalan <albert@...rs.sourceforge.net>,
	Wolfgang Draxinger <Wolfgang.Draxinger@...pus.lmu.de>,
	Bodo Eggert <7eggert@....de>,
	Al Viro <viro@...celfarce.linux.theplanet.co.uk>
Subject: Re: [RFC][PATCH] procfs: add privacy options

Eric W. Biederman schrieb:
> I don't really like filesystem magic options as kernel boot time options.
> Mount time or runtime options are probably more interesting.
> 
> How is it expected that users will use this?

I don't expect admins to switch "privacy" on and off very often.  Once
would be enough, I hope.

Mount options would be easier to use, I agree, but I doubt the added
complexity is worth it.  Kernel options for procfs are not _that_
magical because the kernel mounts it internally, so it's a kernel part,
not a real filesystem ;-)

One question I couldn't find a good answer for regarding remount
options: what to do with processes that have cd'd into a /proc/<pid> dir
belonging to another user when the privacy option is being turned on?
Letting them keep their access is counter-intuitive and taking it away
would need quite invasive changes compared to my patch, I think.

> A lot of the privacy you are talking about is provided by the may_ptrace
> checks in the more sensitive parts of proc so we may want to extend
> that.

You mean using ptrace_may_attach() and/or MAY_PTRACE() for determining
access to all (or at least more) files in /proc/<pid> instead of my
proposed "chmod 500"?  What are the advantages?

Thanks,
René
-
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/