linux-kernel - Re: [PATCH v5 06/12] evm: Ignore INTEGRITY_NOLABEL/INTEGRITY

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Message-ID: <a2ca7317b672c63a40743268b641dd73661c3329.camel@linux.ibm.com>
Date:   Mon, 03 May 2021 10:34:30 -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-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 06/12] evm: Ignore
 INTEGRITY_NOLABEL/INTEGRITY_NOXATTRS if conditions are safe

On Mon, 2021-05-03 at 14:15 +0000, Roberto Sassu wrote:

> > > >  	if (evm_status != INTEGRITY_PASS)
> > > >  		integrity_audit_msg(AUDIT_INTEGRITY_METADATA,
> > > d_backing_inode(dentry),
> > > >  				    dentry->d_name.name,
> > > "appraise_metadata",
> > > > @@ -515,7 +535,8 @@ int evm_inode_setattr(struct dentry *dentry,
> > struct
> > > iattr *attr)
> > > >  		return 0;
> > > >  	evm_status = evm_verify_current_integrity(dentry);
> > > >  	if ((evm_status == INTEGRITY_PASS) ||
> > > > -	    (evm_status == INTEGRITY_NOXATTRS))
> > > > +	    (evm_status == INTEGRITY_NOXATTRS) ||
> > > > +	    (evm_ignore_error_safe(evm_status)))
> > >
> > > It would also remove the INTEGRITY_NOXATTRS test duplication here.
> > 
> > Ok.
> 
> Actually, it does not seem a duplication. Currently, INTEGRITY_NOXATTRS
> is ignored also when the HMAC key is loaded.

The existing INTEGRITY_NOXATTRS exemption is more general and includes
the new case of when EVM HMAC is disabled.  The additional exemption is
only needed for INTEGRITY_NOLABEL, when EVM HMAC is disabled.

Mimi