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From: Paul Moore <paul@paul-moore.com>
To: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	keyrings@vger.kernel.org, SElinux list <selinux@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH] selinux: Fix use of KEY_NEED_* instead of KEY__* perms
Date: Mon, 27 Apr 2020 11:24:17 -0400
Message-ID: <CAHC9VhRQfq+QsmdwkNfLs8bs8xGnBOA3_G=+--13sTmUkdjgCQ@mail.gmail.com> (raw)
In-Reply-To: <CAEjxPJ4ScTAbOOxd8FUa2XcfMqbNuWLxnHhRko=je2+0re8Ztg@mail.gmail.com>

On Mon, Apr 27, 2020 at 10:36 AM Stephen Smalley
<stephen.smalley.work@gmail.com> wrote:
> On Mon, Apr 27, 2020 at 10:13 AM David Howells <dhowells@redhat.com> wrote:
> >
> > Paul Moore <paul@paul-moore.com> wrote:
> >
> > > Okay, can you send the next version of the patch to the SELinux list for
> > > review?
> >
> > Here you go.  Note that I did this a few days ago and I actually used EACCES
> > rather than EPERM.  Which one is one preferred for this?
>
> Generally SELinux returns EACCES unless the hook normally returns
> EPERM (e.g. capable).
> Should we use a build-time or runtime guard to catch introduction of
> new KEY_NEED values without corresponding SELinux
> permissions?
>
> >
> > David
> > ---
> > selinux: Fix use of KEY_NEED_* instead of KEY__* perms
> >
> > selinux_key_getsecurity() is passing the KEY_NEED_* permissions to
> > security_sid_to_context() instead of the KEY__* values.  It happens to work
>
> s/security_sid_to_context/avc_has_perm
>
> > because the values are all coincident.
>
> Shrug.  That was just a requirement on key permissions when they were
> introduced; same is true of capabilities.
> Not opposed to explicitly mapping them now but it isn't really a bug.

I haven't looked at the rest of the patch yet, but I wanted to make a
quick comment on this ... over the years I've seen a number of
problems that crop up because of cross-subsytem assumptions, unless
there is some performance critical path where the mapping is
problematic I would prefer to see a translation layer to help protect
SELinux.

-- 
paul moore
www.paul-moore.com

  reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-17 15:48 Problem with 9ba09998baa9 ("selinux: Implement the watch_key security hook") in linux-next Paul Moore
2020-04-17 16:32 ` Richard Haines
2020-04-17 16:59   ` Paul Moore
2020-04-21 12:29 ` David Howells
2020-04-22 19:20   ` Paul Moore
2020-04-22 21:09     ` Paul Moore
2020-04-24 23:43   ` David Howells
2020-04-26 20:53     ` Paul Moore
2020-04-27 14:12     ` [PATCH] selinux: Fix use of KEY_NEED_* instead of KEY__* perms David Howells
2020-04-27 14:36       ` Stephen Smalley
2020-04-27 15:24         ` Paul Moore [this message]
2020-04-27 17:02       ` Stephen Smalley
2020-04-27 22:17         ` Paul Moore
2020-04-28 12:54 ` [PATCH] selinux: Fix use of KEY_NEED_* instead of KEY__* perms [v2] David Howells
2020-04-28 14:32   ` Stephen Smalley
2020-04-28 15:57   ` David Howells
2020-04-28 16:19     ` Stephen Smalley
2020-05-01 16:37       ` Paul Moore
2020-05-12 22:33       ` [PATCH] keys: Make the KEY_NEED_* perms an enum rather than a mask David Howells
2020-05-13  1:04         ` Paul Moore
2020-05-13 12:58         ` Stephen Smalley
2020-05-13 15:25         ` Casey Schaufler
2020-05-13 23:13         ` David Howells
2020-05-14 12:08           ` Stephen Smalley
2020-05-14 14:45             ` Stephen Smalley
2020-05-13 23:16         ` David Howells
2020-05-13 23:25         ` David Howells
2020-05-14 11:00         ` Jarkko Sakkinen
2020-05-14 16:58         ` [PATCH] keys: Move permissions checking decisions into the checking code David Howells
2020-05-14 17:06           ` Casey Schaufler
2020-05-15 15:06           ` Stephen Smalley
2020-05-15 16:45           ` David Howells
2020-05-15 18:55             ` Stephen Smalley
2020-05-15 19:10               ` Casey Schaufler
2020-05-15 22:27             ` David Howells

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