linux-kernel - Re: [PATCH 07/11] evm: Set IMA_CHANGE_XATTR/ATTR bit if EVM_ALLOW_METADATA

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: <910f7fe3864925d1052f5f35785dd19ed1505fe6.camel@linux.ibm.com>
Date:   Tue, 01 Sep 2020 08:55:09 -0400
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     Roberto Sassu <roberto.sassu@...wei.com>,
        "mjg59@...gle.com" <mjg59@...gle.com>
Cc:     "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Silviu Vlasceanu <Silviu.Vlasceanu@...wei.com>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: Re: [PATCH 07/11] evm: Set IMA_CHANGE_XATTR/ATTR bit if
 EVM_ALLOW_METADATA_WRITES is set

> > > I think it is better to set a flag, maybe a new one, directly in EVM, to notify
> > > the integrity subsystem that iint->evm_status is no longer valid.
> > >
> > > If the EVM flag is set, IMA would reset the appraisal flags, as it uses
> > > iint->evm_status for appraisal. We can consider to reset also the measure
> > > flags when we have a template that includes file metadata.
> > 
> > When would IMA read the EVM flag?   Who would reset the flag?  At what
> > point would it be reset?   Just as EVM shouldn't be resetting the IMA
> > flag, IMA shouldn't be resetting the EVM flag.
> 
> IMA would read the flag in process_measurement() and behave similarly
> to when it processes IMA_CHANGE_ATTR. The flag would be reset by
> evm_verify_hmac().

Sounds good.

Mimi