evm: re-release
in [Kernel]
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From: Serge E. Hallyn on 26 Apr 2010 17:10 Quoting Mimi Zohar (zohar(a)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 > <securityfs>/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 <zohar(a)us.ibm.com> Acked-by: Serge Hallyn <serue(a)us.ibm.com> thanks, -serge -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |