linux-kernel - RE: [PATCH v5 07/12] evm: Allow xattr/attr operations for portable signatures

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Date:   Tue, 4 May 2021 14:28:20 +0000
From:   Roberto Sassu <roberto.sassu@...wei.com>
To:     Mimi Zohar <zohar@...ux.ibm.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 07/12] evm: Allow xattr/attr operations for portable
 signatures

> From: Mimi Zohar [mailto:zohar@...ux.ibm.com]
> Sent: Monday, May 3, 2021 2:13 AM
> Hi Roberto,
> 
> > diff --git a/include/linux/integrity.h b/include/linux/integrity.h
> > index 2271939c5c31..2ea0f2f65ab6 100644
> > --- a/include/linux/integrity.h
> > +++ b/include/linux/integrity.h
> >
> > @@ -238,9 +241,12 @@ static enum integrity_status
> evm_verify_hmac(struct dentry *dentry,
> >  		break;
> >  	}
> >
> > -	if (rc)
> > -		evm_status = (rc == -ENODATA) ?
> > -				INTEGRITY_NOXATTRS : INTEGRITY_FAIL;
> > +	if (rc) {
> > +		evm_status = INTEGRITY_NOXATTRS;
> > +		if (rc != -ENODATA)
> > +			evm_status = evm_immutable ?
> > +				     INTEGRITY_FAIL_IMMUTABLE :
> INTEGRITY_FAIL;
> 
> The original code made an exception for the -ENODATA case.   Using a
> ternary operator made sense in that case.   Inverting the test makes
> the code less readable.  Please use the standard "if" statement
> instead.

Did I understand correctly that the code should be:

                evm_status = INTEGRITY_NOXATTRS;
                if (rc != -ENODATA) {
                        evm_status = INTEGRITY_FAIL;
                        if (evm_immutable)
                                evm_status = INTEGRITY_FAIL_IMMUTABLE;
                }

Thanks

Roberto

HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Li Peng, Li Jian, Shi Yanli

> thanks,
> 
> Mimi