Am 20.05.2011 00:49, schrieb Mimi Zohar: > On Thu, 2011-05-19 at 01:05 -0500, Serge E. Hallyn wrote: >> Quoting Mimi Zohar (zohar@xxxxxxxxxxxxxxxxxx): >>> EVM protects a file's security extended attributes(xattrs) against integrity >>> attacks. This patchset provides the framework and an initial method. The >>> initial method maintains an HMAC-sha1 value across the security extended >>> attributes, storing the HMAC value as the extended attribute 'security.evm'. >>> Other methods of validating the integrity of a file's metadata will be posted >>> separately (eg. EVM-digital-signatures). >>> >>> While this patchset does authenticate the security xattrs, and >>> cryptographically binds them to the inode, coming extensions will bind other >>> directory and inode metadata for more complete protection. To help simplify >>> the review and upstreaming process, each extension will be posted separately >>> (eg. IMA-appraisal, IMA-appraisal-directory). For a general overview of the >>> proposed Linux integrity subsystem, refer to Dave Safford's whitepaper: >>> http://downloads.sf.net/project/linux-ima/linux-ima/Integrity_overview.pdf. >>> >>> EVM depends on the Kernel Key Retention System to provide it with a >>> trusted/encrypted key for the HMAC-sha1 operation. The key is loaded onto the >>> root's keyring using keyctl. Until EVM receives notification that the key has >>> been successfully loaded onto the keyring (echo 1 > <securityfs>/evm), EVM can >>> not create or validate the 'security.evm' xattr, but returns INTEGRITY_UNKNOWN. >>> Loading the key and signaling EVM should be done as early as possible. Normally >>> this is done in the initramfs, which has already been measured as part of the >>> trusted boot. For more information on creating and loading existing >>> trusted/encrypted keys, refer to Documentation/keys-trusted-encrypted.txt. A >>> sample dracut patch, which loads the trusted/encrypted key and enables EVM, is >>> available from http://linu-ima.sourceforge.net/#EVM. >> >> That should read http://linux-ima.sourceforge.net/#EVM. > > Thanks for catching that. The dracut patch, could easily turned into a separate dracut module with its own files, without patching. Somebody did not understand the modular nature of dracut. While you are at it, I happily integrate that module in upstream, if you submit it to the initramfs mailing list. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
