linux-kernel - Re: [PATCH] ima: don't clear IMA_DIGSIG flag when setting non-IMA xattr

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] [day] [month] [year] [list]

Message-ID: <6f2b7320b691669068dda110c29c25f8aae2f244.camel@linux.ibm.com>
Date: Wed, 10 Sep 2025 08:21:33 -0400
From: Mimi Zohar <zohar@...ux.ibm.com>
To: Coiby Xu <coxu@...hat.com>
Cc: linux-integrity@...r.kernel.org, Roberto Sassu
 <roberto.sassu@...wei.com>,
        Dmitry Kasatkin <dmitry.kasatkin@...il.com>,
        Eric Snowberg <eric.snowberg@...cle.com>,
        Paul Moore	
 <paul@...l-moore.com>, James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn"	
 <serge@...lyn.com>,
        "open list:SECURITY SUBSYSTEM"	
 <linux-security-module@...r.kernel.org>,
        open list	
 <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ima: don't clear IMA_DIGSIG flag when setting non-IMA
 xattr

On Wed, 2025-09-10 at 09:36 +0800, Coiby Xu wrote:
> On Mon, Sep 08, 2025 at 04:58:05PM -0400, Mimi Zohar wrote:
> > On Mon, 2025-09-08 at 10:53 -0400, Mimi Zohar wrote:
> > > Hi Coiby,
> > > 
> > > On Mon, 2025-09-08 at 19:12 +0800, Coiby Xu wrote:
> > > > > 
> > > > > Even without an IMA appraise policy, the security xattrs are written out to the
> > > > > filesystem, but the IMA_DIGSIG flag is not cached.
> > > > 
> > > > It seems I miss some context for the above sentence. If no IMA policy is
> > > > configured, no ima_iint_cache will be created. If you mean non-appraisal
> > > > policy, will not caching IMA_DIGSIG flag cause any problem?
> > > 
> > > Sorry.  What I was trying to say is that your test program illustrates the
> > > problem both with or without any of the boot command line options as you
> > > suggested - "ima_appraise=fix evm=fix ima_policy=appraise_tcb".  Writing some
> > > other security xattr is a generic problem, whether the file is in policy or not,
> > > whether IMA or EVM are in fix mode or not.  The rpm-plugin-ima should install
> > > the IMA signature regardless.
> > 
> > My mistake.  An appraise policy indeed needs to be defined for the file
> > signature to be replaced with a file hash.
> 
> Thanks for the clarification! rpm-plugin-ima does try to install IMA
> signature as shown from the following strace output,

Agreed. I was referring to the SELinux label, which would be installed for new
files, but not necessarily re-installed on existing files.  The test program
simplified testing.  Thank you.

Mimi