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From: Vivek Goyal <vgoyal@redhat.com>
To: "Kasatkin, Dmitry" <dmitry.kasatkin@intel.com>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>,
	dhowells@redhat.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 1/1] ima: digital signature verification using asymmetric keys
Date: Mon, 28 Jan 2013 10:15:27 -0500	[thread overview]
Message-ID: <20130128151527.GA5868@redhat.com> (raw)
In-Reply-To: <CALLzPKY9E8VaFf1GUstTnCeYwLOTm6ozdjJFDwSKWk_JR6QF5w@mail.gmail.com>

On Mon, Jan 28, 2013 at 04:54:06PM +0200, Kasatkin, Dmitry wrote:
> On Fri, Jan 25, 2013 at 11:01 PM, Vivek Goyal <vgoyal@redhat.com> wrote:
> > Hi,
> >
> > I am trying to read and understand IMA code. How does digital signature
> > mechanism work.
> >
> > IIUC, evmctl will install a file's signature in security.ima. And later
> > process_measurement() will do following.
> >
> > Calculate digest of file in ima_collect_measurement() and then
> > ima_appraise_measurement() actually compares signatuer against the
> > digest.
> >
> > If yes, ima_collect_measurement() always calculates digest either using
> > md5/sha1 but signatures might have used sha256 or something else. So
> > how does it work. What am I missing.
> 
> Hi,
> 
> Yes, currently it is possible to use only single configured algorithm, which is
> in generally enough. Consider it like a policy.
> Soon it will be a patch which allows to use any hash algorithms, supported by
> asymmetric key verification API.

Ok. I am hoping that it will be more than the kernel command line we
support. In the sense that for digital signatures one needs to parse
the signature, look at what hash algorithm has been used  and then
collect the hash accordingly. It is little different then IMA requirement
of calculating one pre-determine hash for all files.

Thanks
Vivek

  reply	other threads:[~2013-01-28 15:15 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-15 10:34 [RFC 0/1] ima/evm: signature verification support using asymmetric keys Dmitry Kasatkin
2013-01-15 10:34 ` [RFC 1/1] ima: digital signature verification " Dmitry Kasatkin
2013-01-22 22:53   ` Mimi Zohar
2013-01-23  9:03     ` Kasatkin, Dmitry
2013-01-25 21:01       ` Vivek Goyal
2013-01-28 14:54         ` Kasatkin, Dmitry
2013-01-28 15:15           ` Vivek Goyal [this message]
2013-01-28 15:20             ` Kasatkin, Dmitry
2013-01-28 18:52               ` Vivek Goyal
2013-01-28 19:51                 ` Mimi Zohar
2013-01-28 20:13                   ` Vivek Goyal
2013-01-29  0:14                     ` Mimi Zohar
2013-01-29 16:30                       ` Vivek Goyal
2013-01-29  8:53                     ` Kasatkin, Dmitry
2013-01-29  8:48                 ` Kasatkin, Dmitry
2013-01-29 18:39                   ` Vivek Goyal
2013-01-28 18:56               ` Vivek Goyal
2013-01-28 20:15                 ` Mimi Zohar
2013-01-28 20:22                   ` Vivek Goyal
2013-01-29  1:48                     ` Mimi Zohar
2013-01-29 16:58                       ` Vivek Goyal
2013-01-30  6:32                         ` Matthew Garrett
2013-01-30 22:22                           ` Mimi Zohar
2013-01-29 18:20                       ` Vivek Goyal
2013-01-29 20:01                         ` Mimi Zohar
2013-01-29 20:10                           ` Vivek Goyal
2013-01-29 22:26                             ` Mimi Zohar
2013-01-16 19:45 ` [RFC 0/1] ima/evm: signature verification support " Mimi Zohar
2013-01-17 17:52 ` [RFC 1/1] ima: digital signature verification " David Howells
2013-01-17 18:00   ` Kasatkin, Dmitry
2013-01-17 18:03 ` [RFC 0/1] ima/evm: signature verification support " David Howells
2013-01-18 15:16   ` Mimi Zohar

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