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From: David Safford <safford@watson.ibm.com>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: James Morris <jmorris@namei.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Greg KH <greg@kroah.com>,
	Dmitry Kasatkin <dmitry.kasatkin@nokia.com>,
	Arjan van de Ven <arjan@infradead.org>
Subject: Re: [PATCH v5 00/21] EVM
Date: Fri, 20 May 2011 09:06:11 -0400	[thread overview]
Message-ID: <1305896771.15245.11.camel@localhost.localdomain> (raw)
In-Reply-To: <1305853626.2528.50.camel@localhost.localdomain>

On Thu, 2011-05-19 at 21:07 -0400, Mimi Zohar wrote:
> On Fri, 2011-05-20 at 10:51 +1000, James Morris wrote:
> > On Wed, 18 May 2011, Mimi Zohar wrote:
> > 
> > > > Once we have a better understanding of what the feature does and why it
> > > > does it and how it interfaces with the user, we can start looking at
> > > > the implementation.
> > > 
> > > Much appreciated!
> > 
> > What is the status of potential users of the feature?
> > 
> > I recall that MeeGo were planning to use EVM, but they've since changed 
> > their security plans.  Do they still plan to use it?  Are any other users 
> > committing to use EVM?
> > 
> > Also -- this was raised some time back, but I can't find the discussion -- 
> > what does IMA/EVM provide over disk encryption as a protection against 
> > offline attacks?
> > 
> > - James
> 
> Dave Safford's whitepaper discusses this.
> http://downloads.sf.net/project/linux-ima/linux-ima/Integrity_overview.pdf
> 
> Mimi

The short answer is that encryption provides confidentiality, but does
not provide integrity, authenticity, or immutability. 

The easiest way to think about it is to consider a one time pad, which
provides perfect confidentiality, but is trivially bit-twiddled. Yes,
AES is better in this respect, and encrypted file systems can combine
integrity (as long as you encrypt-then-authenticate), but usually they
don't. 

If you want policy driven integrity, authenticity, and immutability,
(and we have two IBM customers wanting them this year), then you want
the combination IMA, IMA-Appraisal, EVM, and Dmitry's digital signature
extensions.

dave

  reply	other threads:[~2011-05-20 13:06 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-16 14:44 [PATCH v5 00/21] EVM Mimi Zohar
2011-05-16 14:44 ` [PATCH v5 01/21] integrity: move ima inode integrity data management Mimi Zohar
2011-05-19  2:06   ` Serge E. Hallyn
2011-05-19 22:45     ` Mimi Zohar
2011-05-16 14:44 ` [PATCH v5 02/21] xattr: define vfs_getxattr_alloc and vfs_xattr_cmp Mimi Zohar
2011-05-19  2:11   ` Serge E. Hallyn
2011-05-16 14:44 ` [PATCH v5 03/21] evm: re-release Mimi Zohar
2011-05-19  6:05   ` Serge E. Hallyn
2011-05-19 22:49     ` Mimi Zohar
2011-05-20 11:12       ` Harald Hoyer
2011-05-20 11:21         ` Mimi Zohar
2011-05-19 21:37   ` Serge E. Hallyn
2011-05-20 12:29     ` Mimi Zohar
2011-05-20 13:43       ` Serge E. Hallyn
2011-05-16 14:44 ` [PATCH v5 04/21] evm: add support for different security.evm data types Mimi Zohar
2011-05-16 14:44 ` [PATCH v5 05/21] ima: move ima_file_free before releasing the file Mimi Zohar
2011-05-19 22:06   ` Serge E. Hallyn
2011-05-20  0:55     ` Mimi Zohar
2011-05-20 13:40       ` Serge E. Hallyn
2011-05-20 14:34         ` Mimi Zohar
2011-05-20 15:25           ` Serge E. Hallyn
2011-05-16 14:45 ` [PATCH v5 06/21] security: imbed evm calls in security hooks Mimi Zohar
2011-05-19 22:13   ` Serge E. Hallyn
2011-05-16 14:45 ` [PATCH v5 07/21] evm: evm_inode_post_removexattr Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 08/21] evm: imbed evm_inode_post_setattr Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 09/21] evm: evm_inode_post_init Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 10/21] fs: add evm_inode_post_init calls Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 11/21] evm: crypto hash replaced by shash Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 12/21] evm: add evm_inode_post_init call in btrfs Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 13/21] evm: add evm_inode_post_init call in gfs2 Mimi Zohar
2011-05-16 15:30   ` Steven Whitehouse
2011-05-16 15:50     ` Mimi Zohar
2011-05-16 16:14       ` Steven Whitehouse
2011-05-16 16:35         ` Mimi Zohar
2011-05-16 17:50           ` Mimi Zohar
2011-05-16 17:57             ` Steven Whitehouse
2011-05-16 18:20               ` Mimi Zohar
2011-05-16 18:23               ` Casey Schaufler
2011-05-16 18:48                 ` Mimi Zohar
2011-05-16 19:25                   ` Casey Schaufler
2011-05-19  0:55                     ` Mimi Zohar
2011-05-19  9:25                       ` Steven Whitehouse
2011-05-16 14:45 ` [PATCH v5 14/21] evm: add evm_inode_post_init call in jffs2 Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 15/21] evm: add evm_inode_post_init call in jfs Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 16/21] evm: add evm_inode_post_init call in xfs Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 17/21] evm: additional parameter to pass integrity cache entry 'iint' Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 18/21] evm: evm_verify_hmac must not return INTEGRITY_UNKNOWN Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 19/21] evm: replace hmac_status with evm_status Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 20/21] evm: permit only valid security.evm xattrs to be updated Mimi Zohar
2011-05-16 14:45 ` [PATCH v5 21/21] evm: add evm_inode_setattr to prevent updating an invalid security.evm Mimi Zohar
2011-05-19  0:25 ` [PATCH v5 00/21] EVM Andrew Morton
2011-05-19  1:51   ` Mimi Zohar
2011-05-20  0:51     ` James Morris
2011-05-20  1:07       ` Mimi Zohar
2011-05-20 13:06         ` David Safford [this message]
2011-05-20 14:13       ` Casey Schaufler
2011-05-26  6:08   ` Pavel Machek
2011-05-26 16:34     ` Casey Schaufler
2011-05-26 18:11       ` David Safford
2011-05-26 18:38         ` Pavel Machek
2011-05-26 19:30           ` Casey Schaufler
2011-05-26 20:02             ` Pavel Machek
2011-05-26 20:32               ` Casey Schaufler
2011-05-26 19:49           ` Mimi Zohar
2011-05-26 20:17             ` Pavel Machek
2011-05-27 17:45               ` David Safford
2011-05-29  6:58                 ` Pavel Machek
2011-05-31 12:05                   ` Mimi Zohar
2011-05-31 13:40                     ` Valdis.Kletnieks
2011-06-01 22:11                   ` Dmitry Kasatkin
2011-05-20 18:50 ` Serge E. Hallyn
2011-05-23 22:09   ` Mimi Zohar

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