Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753648Ab0DZVDf (ORCPT ); Mon, 26 Apr 2010 17:03:35 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:49888 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753167Ab0DZVDd (ORCPT ); Mon, 26 Apr 2010 17:03:33 -0400 Date: Mon, 26 Apr 2010 16:03:33 -0500 From: "Serge E. Hallyn" To: Mimi Zohar Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, James Morris , David Safford , Dave Hansen , Mimi Zohar Subject: Re: [PATCH 04/14] evm: re-release Message-ID: <20100426210333.GB2029@us.ibm.com> References: <1271886594-3719-1-git-send-email-zohar@linux.vnet.ibm.com> <1271886594-3719-5-git-send-email-zohar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1271886594-3719-5-git-send-email-zohar@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2195 Lines: 45 Quoting Mimi Zohar (zohar@linux.vnet.ibm.com): > EVM protects a file's security extended attributes against integrity > attacks. It maintains an HMAC-sha1 value across the extended attributes, > storing the value as the extended attribute 'security.evm'. EVM has gone > through a number of iterations, initially as an LSM module, subsequently > as a LIM integrity provider, and now, when co-located with a security_ > hook, embedded directly in the security_ hook, similar to IMA. > > This is the first part of a local file integrity verification system. > While this part does authenticate the selected extended attributes, and > cryptographically bind them to the inode, coming extensions will bind > other directory and inode metadata for more complete protection. The > set of protected security extended attributes is configured at compile. > > EVM depends on the Kernel Key Retention System to provide it with the > kernel master key for the HMAC operation. The kernel master key is > securely loaded onto the root's keyring, typically by 'loadkernkey', > which either uses the TPM sealed secret key, if available, or a > password requested from the console. To signal EVM, that the key has > been loaded onto the keyring, 'echo 1 > /evm'. This is > normally done in the initrd, which has already been measured as part > of the trusted boot. (Refer to http://linux-ima.sourceforge.net/#EVM.) > > EVM adds the following three calls to the existing security hooks, > evm_inode_setxattr(), evm_inode_post_setxattr(), and > evm_inode_removexattr. > > To initialize and update the 'security.evm' extended attribute, EVM > defines three calls: evm_inode_post_init(), evm_inode_post_setattr() > and evm_inode_post_removexattr() hooks. > > To verify the integrity of an extended attribute, EVM exports > evm_verifyxattr(). > > Signed-off-by: Mimi Zohar Acked-by: Serge Hallyn thanks, -serge -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/