Re: [PATCH] docs: Extend trusted keys documentation for TPM 2.0
From: Randy Dunlap
Date: Fri Oct 19 2018 - 19:07:47 EST
Feel free to ignore my comments. I don't know anything about TPM.
On 10/19/18 3:17 AM, 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>
> .../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".
It appears to be TrouSerS or maybe just trousers (no ').
BTW, is this still the current location for it or has it moved elsewhere?
> +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
Is that handle value important? It doesn't seem to be used later...
> + #> tpm2_evictcontrol -c key.ctxt -p 0x81000001
> + persistentHandle: 0x81000001
> keyctl add trusted name "new keylen [options]" ring
> @@ -30,7 +53,9 @@ Usage::
> keyctl print keyid
> - 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