Re: [RFC 0/1] ima/evm: signature verification support using asymmetric keys

[Mimi Zohar <zohar@linux.vnet.ibm.com>]

On Tue, 2013-01-15 at 12:34 +0200, Dmitry Kasatkin wrote:
> Asymmetric keys were introduced in linux-3.7 to verify the signature on signed
> kernel modules.  The asymmetric keys infrastructure abstracts the signature
> verification from the crypto details.  This patch adds IMA/EVM signature
> verification using asymmetric keys.  Support for additional signature
> verification methods can now be delegated to the asymmetric key infrastructure.
> 
> Although the module signature header and the IMA/EVM signature header could
> use the same header format, to minimize the signature length and save space
> in the extended attribute, the IMA/EVM header format is different than the
> module signature header.  The main difference is that the key identifier is
> a sha1[12 - 19] hash of the key modulus and exponent and similar to the current
> implementation. The only purpose is to identify corresponding key in the kernel
> keyring. ima-evm-utils was updated to support the new signature format.

David, are you ok with how support for asymmetric keys is being added to
EVM/IMA-appraisal for verifying signatures?  Any comments?

thanks,

Mimi