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From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
	"mjg59@google.com" <mjg59@google.com>
Cc: "linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 07/12] evm: Allow xattr/attr operations for portable signatures
Date: Tue, 04 May 2021 10:49:53 -0400
Message-ID: <10f9ab52c487b9dcde000f8aee77c8e04979a485.camel@linux.ibm.com> (raw)
In-Reply-To: <f26f4b6fd3074bb4a6f0f0ff4911a202@huawei.com>

On Tue, 2021-05-04 at 14:28 +0000, Roberto Sassu wrote:
> > From: Mimi Zohar [mailto:zohar@linux.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 != -ENODA
>                         evm_status = INTEGRITY_FAIL;
>                         if (evm_immutable)
>                                 evm_status = INTEGRITY_FAIL_IMMUTABLE;
>                 }
> 
 
                if (rc == -ENODATA)
                        evm_status = INTEGRITY_NOXATTRS;
                else if (evm_status == evm_immutable)
                        evm_status = INTEGRITY_FAIL_IMMUTABLE;
                else
                        evm_status = INTEGRITY_FAIL;

I think keeping it simple makes it really clear that ENODATA is an
exception.

thanks,

Mimi


  reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 10:52 [PATCH v5 00/12] evm: Improve usability of " Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 01/12] evm: Execute evm_inode_init_security() only when an HMAC key is loaded Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 02/12] evm: Load EVM key in ima_load_x509() to avoid appraisal Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 03/12] evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded Roberto Sassu
2021-04-30 20:28   ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 04/12] ima: Move ima_reset_appraise_flags() call to post hooks Roberto Sassu
2021-04-07 16:17   ` Casey Schaufler
2021-04-07 16:31     ` Roberto Sassu
2021-04-26 19:49     ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 05/12] evm: Introduce evm_status_revalidate() Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 06/12] evm: Ignore INTEGRITY_NOLABEL/INTEGRITY_NOXATTRS if conditions are safe Roberto Sassu
2021-05-03  0:12   ` Mimi Zohar
2021-05-03  7:55     ` Roberto Sassu
2021-05-03 12:07       ` Mimi Zohar
2021-05-03 14:15       ` Roberto Sassu
2021-05-03 14:34         ` Mimi Zohar
2021-05-04 13:16           ` Roberto Sassu
2021-05-04 13:45             ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 07/12] evm: Allow xattr/attr operations for portable signatures Roberto Sassu
2021-05-03  0:12   ` Mimi Zohar
2021-05-04 14:28     ` Roberto Sassu
2021-05-04 14:49       ` Mimi Zohar [this message]
2021-04-07 10:52 ` [PATCH v5 08/12] evm: Pass user namespace to set/remove xattr hooks Roberto Sassu
2021-04-07 12:06   ` Christian Brauner
2021-04-07 10:52 ` [PATCH v5 09/12] evm: Allow setxattr() and setattr() for unmodified metadata Roberto Sassu
2021-04-07 12:05   ` Christian Brauner
2021-04-07 15:23   ` kernel test robot
2021-04-07 18:14   ` kernel test robot
2021-04-07 19:28     ` [RESEND][PATCH " Roberto Sassu
2021-05-03 13:00   ` [PATCH " Mimi Zohar
2021-05-03 14:48     ` Roberto Sassu
2021-05-03 15:13       ` Mimi Zohar
2021-05-03 15:30         ` Roberto Sassu
2021-05-03 15:11     ` Roberto Sassu
2021-05-03 15:26       ` Mimi Zohar
2021-05-03 15:32         ` Roberto Sassu
2021-05-03 15:48           ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 10/12] ima: Allow imasig requirement to be satisfied by EVM portable signatures Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 11/12] ima: Introduce template field evmsig and write to field sig as fallback Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 12/12] ima: Don't remove security.ima if file must not be appraised Roberto Sassu

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