Re: [PATCH] docs: Extend trusted keys documentation for TPM 2.0

[Jerry Snitselaar]

On Fri Oct 19 18, Stefan Berger wrote:
> Extend the documentation for trusted keys with documentation for how to
> set up a key for a TPM 2.0 so it can be used with a TPM 2.0 as well.
>
> Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>

Acked-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>

> ---
> .../security/keys/trusted-encrypted.rst       | 31 ++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
> index 3bb24e09a332..6ec6bb2ac497 100644
> --- a/Documentation/security/keys/trusted-encrypted.rst
> +++ b/Documentation/security/keys/trusted-encrypted.rst
> @@ -18,10 +18,33 @@ integrity verifications match.  A loaded Trusted Key can be updated with new
> when the kernel and initramfs are updated.  The same key can have many saved
> blobs under different PCR values, so multiple boots are easily supported.
>
> +TPM 1.2
> +-------
> +
> By default, trusted keys are sealed under the SRK, which has the default
> authorization value (20 zeros).  This can be set at takeownership time with the
> trouser's utility: "tpm_takeownership -u -z".
>
> +TPM 2.0
> +-------
> +
> +The user must first create a storage key and make it persistent, so the key is
> +available after reboot. This can be done using the following commands.
> +
> +With the IBM TSS 2 stack::
> +
> +  #> tsscreateprimary -hi o -st
> +  Handle 80000000
> +  #> tssevictcontrol -hi o -ho 80000000 -hp 81000001
> +
> +Or with the Intel TSS 2 stack::
> +
> +  #> tpm2_createprimary --hierarchy o -G rsa2048 -o key.ctxt
> +  [...]
> +  handle: 0x800000FF
> +  #> tpm2_evictcontrol -c key.ctxt -p 0x81000001
> +  persistentHandle: 0x81000001
> +
> Usage::
>
>     keyctl add trusted name "new keylen [options]" ring
> @@ -30,7 +53,9 @@ Usage::
>     keyctl print keyid
>
>     options:
> -       keyhandle=    ascii hex value of sealing key default 0x40000000 (SRK)
> +       keyhandle=    ascii hex value of sealing key
> +                       TPM 1.2: default 0x40000000 (SRK)
> +                       TPM 2.0: no default; must be passed every time
>        keyauth=	     ascii hex auth for sealing key default 0x00...i
>                      (40 ascii zeros)
>        blobauth=     ascii hex auth for sealed data default 0x00...
> @@ -84,6 +109,10 @@ Examples of trusted and encrypted key usage:
>
> Create and save a trusted key named "kmk" of length 32 bytes::
>
> +Note: When using a TPM 2.0 with a persistent key with handle 0x81000001,
> +append 'keyhandle=0x81000001' to statements between quotes, such as
> +"new 32 keyhandle=0x81000001".
> +
>     $ keyctl add trusted kmk "new 32" @u
>     440502848
>
> --
> 2.17.2