Re: [RFC PATCH -next] ima: Make tpm hash configurable

Mimi Zohar
2023-08-30T18:47:36Z

On Wed, 2023-08-30 at 17:14 +0800, Guozihua (Scott) wrote:
> On 2023/8/19 7:17, Mimi Zohar wrote:
> > On Fri, 2023-08-18 at 09:25 +0800, Guozihua (Scott) wrote:
> >> On 2023/8/17 22:19, Mimi Zohar wrote:
> >>> On Thu, 2023-08-17 at 14:13 +0800, GUO Zihua wrote:
> > [...]
> >
> >>> Other proposals have changed the hard coded hash algorithm and PCR
> >>> value from SHA1 to SHA256. Both that proposal and this will break
> >>> existing userspace applications.
> >>
> >> This is the part I would like to "RFC" on, and thanks for the comment!
> >
> > Another proposal included all of the enabled TPM bank digests.
> Will this introduce some performance issue? I don't think we should be
> calculating various hashes on the same thing again and again.

Per TPM bank specific hashes are already being calculated and extended
into the TPM banks. Refer to ima_calc_field_array_hash().

--
thanks,

Mimi