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From: Roberto Sassu <roberto.sassu@huawei.com>
To: Mimi Zohar <zohar@linux.ibm.com>,
	"paul@paul-moore.com" <paul@paul-moore.com>
Cc: "stephen.smalley.work@gmail.com" <stephen.smalley.work@gmail.com>,
	"prsriva02@gmail.com" <prsriva02@gmail.com>,
	"tusharsu@linux.microsoft.com" <tusharsu@linux.microsoft.com>,
	"nramas@linux.microsoft.com" <nramas@linux.microsoft.com>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"selinux@vger.kernel.org" <selinux@vger.kernel.org>
Subject: RE: [PATCH v3 2/3] ima: Return int in the functions to measure a buffer
Date: Tue, 20 Jul 2021 12:38:43 +0000	[thread overview]
Message-ID: <bd953894da3041d5969da645db2f982e@huawei.com> (raw)
In-Reply-To: <2f4920dbdb16156e1af5cf78f592a5cf07ec3176.camel@linux.ibm.com>

> From: Mimi Zohar [mailto:zohar@linux.ibm.com]
> Sent: Monday, July 19, 2021 10:28 PM
> Hi Roberto,
> 
> On Mon, 2021-07-05 at 11:09 +0200, Roberto Sassu wrote:
> > ima_measure_critical_data() and process_buffer_measurement() currently
> > don't return a result. A caller wouldn't be able to know whether those
> > functions were executed successfully.
> 
> Missing is an explanation as to why these functions aren't currently
> returning a result.   The LSM/IMA hooks only return a negative result
> for failure to appraise a file's integrity, not measure a file.  Only
> failure to appraise a file's integrity results in preventing the file
> from being read/executed/mmaped.  Other failures are only audited.

Hi Mimi

ok, will add it.

> > This patch modifies the return type from void to int, and returns 0 if the
> > buffer has been successfully measured, a negative value otherwise.
> 
> Needed here is an explanation as to why ima_measure_critical_data() is
> special.

We don't want to unnecessarily calculate the digest twice.

> > Also, this patch does not modify the behavior of existing callers by
> > processing the returned value. For those, the return value is ignored.
> 
> I agree that the existing behavior shouldn't change, but will this
> result in the bots complaining?

If I remember correctly, I didn't get any error even with W=1.

Thanks

Roberto

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

> thanks,
> 
> Mimi


  reply	other threads:[~2021-07-20 12:38 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05  9:09 [PATCH v3 0/3] ima: Provide more info about buffer measurement Roberto Sassu
2021-07-05  9:09 ` [PATCH v3 1/3] ima: Introduce ima_get_current_hash_algo() Roberto Sassu
2021-07-05  9:09 ` [PATCH v3 2/3] ima: Return int in the functions to measure a buffer Roberto Sassu
2021-07-06 19:21   ` Lakshmi Ramasubramanian
2021-07-19 20:28   ` Mimi Zohar
2021-07-20 12:38     ` Roberto Sassu [this message]
2021-07-20 13:01       ` Mimi Zohar
2021-07-05  9:09 ` [PATCH v3 3/3] ima: Add digest and digest_len params to " Roberto Sassu
2021-07-06 19:24   ` Lakshmi Ramasubramanian
2021-07-13  2:40   ` Paul Moore
2021-07-19 20:59   ` Mimi Zohar

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