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From: Mimi Zohar <zohar@linux.ibm.com>
To: THOBY Simon <Simon.THOBY@viveris.fr>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>
Subject: Re: Weak hash algorithms allowed with DIGEST_NG
Date: Wed, 07 Jul 2021 12:18:56 -0400	[thread overview]
Message-ID: <10dde047d76b447f32ca91356599be679b8a76e5.camel@linux.ibm.com> (raw)
In-Reply-To: <AM4PR0902MB174890B0AB5F5D96E4366FFD941A9@AM4PR0902MB1748.eurprd09.prod.outlook.com>

On Wed, 2021-07-07 at 15:10 +0000, THOBY Simon wrote:

> > > Is there any way to enforce the use of the hash specified in the
> > > 'ima_hash' cmdline parameter ?
> > 
> > The cmdline parameter overrides the compile time default hash algorithm
> > used for (re-)calculating the file hash.
> > 
> 
> Yes, but that only applies to the hashes performed automatically by the kernel,
> not to a user relabelling his whole / with
> find / \( -fstype rootfs -o -fstype ext4 \) -type f -uid 0 -exec evmctl ima_hash '{}' 2> /dev/null \;
> and forgetting to specify a stronger algorithm (that's how I learned of this pitfall myself).

If you were interested in limiting which algorithms could be used, the
change would be made in ima_inode_setxattr().  I'd be interested in
seeing what you come up with.

thanks,

Mimi


      reply	other threads:[~2021-07-07 16:19 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-07  9:54 Weak hash algorithms allowed with DIGEST_NG THOBY Simon
2021-07-07 14:37 ` Mimi Zohar
2021-07-07 15:10   ` THOBY Simon
2021-07-07 16:18     ` Mimi Zohar [this message]

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