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From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
	"jarkko.sakkinen@linux.intel.com"
	<jarkko.sakkinen@linux.intel.com>,
	"james.bottomley@hansenpartnership.com" 
	<james.bottomley@hansenpartnership.com>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>
Cc: "linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Silviu Vlasceanu <Silviu.Vlasceanu@huawei.com>
Subject: Re: [PATCH 7/8] ima: use ima_hash_algo for collision detection in the measurement list
Date: Fri, 31 Jan 2020 09:50:34 -0500
Message-ID: <1580482234.6104.92.camel@linux.ibm.com> (raw)
In-Reply-To: <e299058034b94143af6fc1da4ae2c708@huawei.com>

On Fri, 2020-01-31 at 14:41 +0000, Roberto Sassu wrote:
> I thought that using a stronger algorithm for hash collision detection but
> doing remote attestation with the weaker would not bring additional value.
> 
> If there is a hash collision on SHA1, an attacker can still replace the data of
> one of the two entries in the measurement list with the data of the other
> without being detected (without additional countermeasures).
> 
> If the verifier additionally checks for duplicate template digests, he could
> detect the attack (IMA would not add a new measurement entry with the
> same template digest of previous entries).
> 
> Ok, I will use ima_hash_algo for hash collision detection.

Thanks!

Mimi


  reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-27 17:04 [PATCH 0/8] ima: support stronger algorithms for attestation Roberto Sassu
2020-01-27 17:04 ` [PATCH 1/8] tpm: initialize crypto_id of allocated_banks to HASH_ALGO__LAST Roberto Sassu
2020-01-29  8:39   ` Petr Vorel
2020-01-30  8:47   ` Jarkko Sakkinen
2020-01-30 16:11     ` Roberto Sassu
2020-01-31 13:33       ` Mimi Zohar
2020-02-01 17:10         ` Jarkko Sakkinen
2020-01-27 17:04 ` [PATCH 2/8] ima: evaluate error in init_ima() Roberto Sassu
2020-01-31 13:33   ` Mimi Zohar
2020-01-27 17:04 ` [PATCH 3/8] ima: store template digest directly in ima_template_entry Roberto Sassu
2020-01-27 17:04 ` [PATCH 4/8] ima: switch to dynamically allocated buffer for template digests Roberto Sassu
2020-01-27 17:04 ` [PATCH 5/8] ima: allocate and initialize tfm for each PCR bank Roberto Sassu
2020-01-31 12:18   ` Mimi Zohar
2020-01-31 13:42     ` Roberto Sassu
2020-01-31 13:58       ` Mimi Zohar
2020-01-27 17:04 ` [PATCH 6/8] ima: calculate and extend PCR with digests in ima_template_entry Roberto Sassu
2020-01-27 17:29   ` Roberto Sassu
2020-01-27 17:04 ` [PATCH 7/8] ima: use ima_hash_algo for collision detection in the measurement list Roberto Sassu
2020-01-30 22:26   ` Mimi Zohar
2020-01-31 14:02     ` Roberto Sassu
2020-01-31 14:22       ` Mimi Zohar
2020-01-31 14:41         ` Roberto Sassu
2020-01-31 14:50           ` Mimi Zohar [this message]
2020-01-27 17:04 ` [PATCH 8/8] ima: switch to ima_hash_algo for boot aggregate Roberto Sassu
2020-01-31 15:21   ` Roberto Sassu
2020-01-30 22:26 ` [PATCH 0/8] ima: support stronger algorithms for attestation Mimi Zohar

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