LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Stephen Smalley <sds@tycho.nsa.gov>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@osdl.org>, Ingo Molnar <mingo@elte.hu>,
tglx@linutronix.de, linux-kernel@vger.kernel.org,
selinux@tycho.nsa.gov, James Morris <jmorris@namei.org>,
Eric Paris <eparis@parisplace.org>
Subject: Re: [PATCH 2/2] sysctl: Restore the selinux path based label lookup for sysctls.
Date: Thu, 08 Feb 2007 13:13:24 -0500 [thread overview]
Message-ID: <1170958404.11912.313.camel@moss-spartans.epoch.ncsc.mil> (raw)
In-Reply-To: <m14ppwa64j.fsf@ebiederm.dsl.xmission.com>
On Thu, 2007-02-08 at 10:53 -0700, Eric W. Biederman wrote:
> Stephen Smalley <sds@tycho.nsa.gov> writes:
>
> >
> > Hmmm...turns out to not be quite enough, as the /proc/sys inodes aren't
> > truly private to the fs, so we can run into them in a variety of
> > security hooks beyond just the inode hooks, such as
> > security_file_permission (when reading and writing them via the vfs
> > helpers), security_sb_mount (when mounting other filesystems on
> > directories in proc like binfmt_misc), and deeper within the security
> > module itself (as in flush_unauthorized_files upon inheritance across
> > execve). So I think we have to add an IS_PRIVATE() guard within
> > SELinux, as below. Note however that the use of the private flag here
> > could be confusing, as these inodes are _not_ private to the fs, are
> > exposed to userspace, and security modules must implement the sysctl
> > hook to get any access control over them.
>
> Agreed, the naming is confusing, and using private here doesn't quite
> feel right.
>
> A practical question is: Will we ever encounter these inodes
> in the inode_init() path from superblock_init?
Possibly, during setup upon initial policy load (initiated by /sbin/init
these days) from selinux_complete_init, as early userspace may have
already been accessing them.
> If all of the accesses
> that we care about go through inode_doinit_with_dentry we can just
> walk the dcache to get the names, and that should work for the normal
> proc case as well.
Walking the proc_dir_entry tree (or the ctl_table tree) is preferable as
it is a stable, user-immutable representation. Also avoids taking the
dcache lock.
> A somewhat related question: How do you handle security labels for
> sysfs? No fine grained security yet.
Right, they are all mapped to a single label presently. I was thinking
of handling that from userspace after introducing a setxattr handler for
sysfs and a way to preserve the SID on the entry (likely caching it in
the sysfs_dirent and propagating that to the inode when the inode is
populated from the sysfs_dirent). Then early userspace could walk sysfs
and apply finer-grained labeling from a configuration.
> If it doesn't look easy to solve this another way I will certainly
> go with marking the inodes private.
--
Stephen Smalley
National Security Agency
next prev parent reply other threads:[~2007-02-08 18:18 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200701280106.l0S16CG3019873@shell0.pdx.osdl.net>
[not found] ` <20070127172410.2b041952.akpm@osdl.org>
[not found] ` <1169972718.17469.164.camel@localhost.localdomain>
[not found] ` <20070128003549.2ca38dc8.akpm@osdl.org>
[not found] ` <20070128093358.GA2071@elte.hu>
[not found] ` <20070128095712.GA6485@elte.hu>
[not found] ` <20070128100627.GA8416@elte.hu>
[not found] ` <20070128104548.a835d859.akpm@osdl.org>
2007-01-28 19:21 ` [PATCH] sysctl selinux: Don't look at table->de Eric W. Biederman
2007-01-29 13:04 ` Stephen Smalley
2007-01-29 15:23 ` James Morris
2007-01-29 17:55 ` Eric W. Biederman
2007-01-29 19:26 ` Stephen Smalley
2007-01-29 17:43 ` Eric W. Biederman
2007-01-29 18:43 ` Stephen Smalley
2007-01-29 19:08 ` Casey Schaufler
2007-01-29 20:07 ` Stephen Smalley
2007-01-30 10:25 ` Christoph Hellwig
2007-01-30 17:19 ` Casey Schaufler
2007-01-29 19:16 ` Eric W. Biederman
2007-01-29 23:28 ` Russell Coker
2007-02-06 21:16 ` [PATCH 1/2] sysctl: Add a parent entry to ctl_table and set the parent entry Eric W. Biederman
2007-02-06 21:21 ` [PATCH 2/2] sysctl: Restore the selinux path based label lookup for sysctls Eric W. Biederman
2007-02-07 18:24 ` Stephen Smalley
2007-02-07 21:12 ` Stephen Smalley
2007-02-07 21:54 ` Stephen Smalley
2007-02-07 22:21 ` Eric W. Biederman
2007-02-08 15:07 ` Stephen Smalley
2007-02-08 1:57 ` Eric W. Biederman
2007-02-08 15:01 ` Stephen Smalley
2007-02-08 17:53 ` Eric W. Biederman
2007-02-08 18:13 ` Stephen Smalley [this message]
2007-02-08 22:17 ` Eric W. Biederman
2007-02-08 22:51 ` [PATCH 0/5] sysctl cleanup selinux fixes Eric W. Biederman
2007-02-08 22:53 ` [PATCH 1/5] sysctl: Remove declaration of nonexistent sysctl_init() Eric W. Biederman
2007-02-08 22:54 ` [PATCH 2/5] sysctl: Set the parent field in the root sysctl table Eric W. Biederman
2007-02-08 22:55 ` [PATCH 3/5] sysctl: Fix the selinux_sysctl_get_sid Eric W. Biederman
2007-02-08 23:02 ` [PATCH 4/5] selinux: Enhance selinux to always ignore private inodes Eric W. Biederman
2007-02-08 23:04 ` [PATCH 5/5] sysctl: Hide the sysctl proc inodes from selinux Eric W. Biederman
2007-02-09 12:26 ` [PATCH 4/5] selinux: Enhance selinux to always ignore private inodes Stephen Smalley
2007-02-09 12:24 ` [PATCH 3/5] sysctl: Fix the selinux_sysctl_get_sid Stephen Smalley
2007-02-09 11:05 ` [PATCH 0/5] sysctl cleanup selinux fixes Andrew Morton
2007-02-09 18:09 ` Eric W. Biederman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1170958404.11912.313.camel@moss-spartans.epoch.ncsc.mil \
--to=sds@tycho.nsa.gov \
--cc=akpm@osdl.org \
--cc=ebiederm@xmission.com \
--cc=eparis@parisplace.org \
--cc=jmorris@namei.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=selinux@tycho.nsa.gov \
--cc=tglx@linutronix.de \
--subject='Re: [PATCH 2/2] sysctl: Restore the selinux path based label lookup for sysctls.' \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).