Re: [RFC PATCH 1/2] tpm: add some algorithm and constant definitions from the TPM spec

Jarkko Sakkinen
2024-05-14T22:51:55Z

I'll go through the code changes. I've barely skimmed them because I
needed to understand the gist of the cover letter first and was busy
with 6.10 release and asymmetric keys.

On Sat May 4, 2024 at 1:16 AM EEST, Ignat Korchagin wrote:
> In preparation for implementing TPM derived keys we need to use some new TPM
> functionality in the kernel, so add relevant constant definitions.

Define "TPM derived key" what is. It is *undefined* at this point of the
Git history.

>
> Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
> ---
> include/linux/tpm.h | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 4ee9d13749ad..5be0808b1b91 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -35,6 +35,7 @@ struct trusted_key_options;
> enum tpm_algorithms {
> TPM_ALG_ERROR = 0x0000,
> TPM_ALG_SHA1 = 0x0004,
> + TPM_ALG_HMAC = 0x0005,
> TPM_ALG_KEYEDHASH = 0x0008,
> TPM_ALG_SHA256 = 0x000B,
> TPM_ALG_SHA384 = 0x000C,

I had a point after all when asking for split and it was about this
patch. This should be a separate comment and with a clear rationale what
for this is required for the new key type.

It is a logically separate change [1].

> @@ -209,6 +210,7 @@ enum tpm2_return_codes {
> TPM2_RC_DISABLED = 0x0120,
> TPM2_RC_UPGRADE = 0x012D,
> TPM2_RC_COMMAND_CODE = 0x0143,
> + TPM2_RC_OBJECT_MEMORY = 0x0902,
> TPM2_RC_TESTING = 0x090A, /* RC_WARN */
> TPM2_RC_REFERENCE_H0 = 0x0910,
> TPM2_RC_RETRY = 0x0922,

Ditto.

> @@ -227,6 +229,7 @@ enum tpm2_command_codes {
> TPM2_CC_CREATE = 0x0153,
> TPM2_CC_LOAD = 0x0157,
> TPM2_CC_SEQUENCE_UPDATE = 0x015C,
> + TPM2_CC_SIGN = 0x015D,
> TPM2_CC_UNSEAL = 0x015E,
> TPM2_CC_CONTEXT_LOAD = 0x0161,
> TPM2_CC_CONTEXT_SAVE = 0x0162,

Ditto.

> @@ -234,6 +237,7 @@ enum tpm2_command_codes {
> TPM2_CC_VERIFY_SIGNATURE = 0x0177,
> TPM2_CC_GET_CAPABILITY = 0x017A,
> TPM2_CC_GET_RANDOM = 0x017B,
> + TPM2_CC_HASH = 0x017D,
> TPM2_CC_PCR_READ = 0x017E,
> TPM2_CC_PCR_EXTEND = 0x0182,
> TPM2_CC_EVENT_SEQUENCE_COMPLETE = 0x0185,

Ditto.

> @@ -243,7 +247,8 @@ enum tpm2_command_codes {
> };
>
> enum tpm2_permanent_handles {
> - TPM2_RS_PW = 0x40000009,
> + TPM2_RH_OWNER = 0x40000001,

Ditto.

> + TPM2_RS_PW = 0x40000009,
> };
>
> enum tpm2_capabilities {
> @@ -312,9 +317,12 @@ struct tpm_buf {
> };
>
> enum tpm2_object_attributes {
> - TPM2_OA_FIXED_TPM = BIT(1),
> - TPM2_OA_FIXED_PARENT = BIT(4),
> - TPM2_OA_USER_WITH_AUTH = BIT(6),
> + TPM2_OA_FIXED_TPM = BIT(1),
> + TPM2_OA_FIXED_PARENT = BIT(4),
> + TPM2_OA_SENSITIVE_DATA_ORIGIN = BIT(5),
> + TPM2_OA_USER_WITH_AUTH = BIT(6),
> + TPM2_OA_RESTRICTED = BIT(16),
> + TPM2_OA_SIGN = BIT(18),
> };
>
> enum tpm2_session_attributes {

Ditto.

[1] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#separate-your-changes

BR, Jarkko