Re: [PATCH v4 4/6] tpm: sandbox: Update for needed TPM2 capabilities

Ilias Apalodimas
2023-01-26T06:42:06Z

On Wed, Jan 25, 2023 at 11:18:08AM -0600, Eddie James wrote:
> The driver needs to support getting the PCRs in the capabilities
> command. Fix various other things and support the max number
> of PCRs for TPM2.
>
> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> Reviewed-by: Simon Glass <sjg@chromium.org>
> ---
> drivers/tpm/tpm2_tis_sandbox.c | 100 ++++++++++++++++++++++++---------
> 1 file changed, 72 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/tpm/tpm2_tis_sandbox.c b/drivers/tpm/tpm2_tis_sandbox.c
> index dd94bdc31f..ea7fb5e3cb 100644
> --- a/drivers/tpm/tpm2_tis_sandbox.c
> +++ b/drivers/tpm/tpm2_tis_sandbox.c
> @@ -22,11 +22,6 @@ enum tpm2_hierarchy {
> TPM2_HIERARCHY_NB,
> };
>
> -/* Subset of supported capabilities */
> -enum tpm2_capability {
> - TPM_CAP_TPM_PROPERTIES = 0x6,
> -};
> -
> /* Subset of supported properties */
> #define TPM2_PROPERTIES_OFFSET 0x0000020E
>
> @@ -38,7 +33,8 @@ enum tpm2_cap_tpm_property {
> TPM2_PROPERTY_NB,
> };
>
> -#define SANDBOX_TPM_PCR_NB 1
> +#define SANDBOX_TPM_PCR_NB TPM2_MAX_PCRS
> +#define SANDBOX_TPM_PCR_SELECT_MAX ((SANDBOX_TPM_PCR_NB + 7) / 8)
>
> /*
> * Information about our TPM emulation. This is preserved in the sandbox
> @@ -433,7 +429,7 @@ static int sandbox_tpm2_xfer(struct udevice *dev, const u8 *sendbuf,
> int i, j;
>
> /* TPM2_GetProperty */
> - u32 capability, property, property_count;
> + u32 capability, property, property_count, val;
>
> /* TPM2_PCR_Read/Extend variables */
> int pcr_index = 0;
> @@ -542,19 +538,32 @@ static int sandbox_tpm2_xfer(struct udevice *dev, const u8 *sendbuf,
> case TPM2_CC_GET_CAPABILITY:
> capability = get_unaligned_be32(sent);
> sent += sizeof(capability);
> - if (capability != TPM_CAP_TPM_PROPERTIES) {
> - printf("Sandbox TPM only support TPM_CAPABILITIES\n");
> - return TPM2_RC_HANDLE;
> - }
> -
> property = get_unaligned_be32(sent);
> sent += sizeof(property);
> - property -= TPM2_PROPERTIES_OFFSET;
> -
> property_count = get_unaligned_be32(sent);
> sent += sizeof(property_count);
> - if (!property_count ||
> - property + property_count > TPM2_PROPERTY_NB) {
> +
> + switch (capability) {
> + case TPM2_CAP_PCRS:
> + break;
> + case TPM2_CAP_TPM_PROPERTIES:
> + if (!property_count) {
> + rc = TPM2_RC_HANDLE;
> + return sandbox_tpm2_fill_buf(recv, recv_len,
> + tag, rc);
> + }
> +
> + if (property > TPM2_PROPERTIES_OFFSET &&
> + ((property - TPM2_PROPERTIES_OFFSET) +
> + property_count > TPM2_PROPERTY_NB)) {
> + rc = TPM2_RC_HANDLE;
> + return sandbox_tpm2_fill_buf(recv, recv_len,
> + tag, rc);
> + }
> + break;
> + default:
> + printf("Sandbox TPM2 only supports TPM2_CAP_PCRS or "
> + "TPM2_CAP_TPM_PROPERTIES\n");
> rc = TPM2_RC_HANDLE;
> return sandbox_tpm2_fill_buf(recv, recv_len, tag, rc);
> }
> @@ -578,18 +587,53 @@ static int sandbox_tpm2_xfer(struct udevice *dev, const u8 *sendbuf,
> put_unaligned_be32(capability, recv);
> recv += sizeof(capability);
>
> - /* Give the number of properties that follow */
> - put_unaligned_be32(property_count, recv);
> - recv += sizeof(property_count);
> -
> - /* Fill with the properties */
> - for (i = 0; i < property_count; i++) {
> - put_unaligned_be32(TPM2_PROPERTIES_OFFSET + property +
> - i, recv);
> - recv += sizeof(property);
> - put_unaligned_be32(tpm->properties[property + i],
> - recv);
> - recv += sizeof(property);
> + switch (capability) {
> + case TPM2_CAP_PCRS:
> + /* Give the number of algorithms supported - just SHA256 */
> + put_unaligned_be32(1, recv);
> + recv += sizeof(u32);
> +
> + /* Give SHA256 algorithm */
> + put_unaligned_be16(TPM2_ALG_SHA256, recv);
> + recv += sizeof(u16);
> +
> + /* Select the PCRs supported */
> + *recv = SANDBOX_TPM_PCR_SELECT_MAX;
> + recv++;
> +
> + /* Activate all the PCR bits */
> + for (i = 0; i < SANDBOX_TPM_PCR_SELECT_MAX; ++i) {
> + *recv = 0xff;
> + recv++;
> + }
> + break;
> + case TPM2_CAP_TPM_PROPERTIES:
> + /* Give the number of properties that follow */
> + put_unaligned_be32(property_count, recv);
> + recv += sizeof(property_count);
> +
> + /* Fill with the properties */
> + for (i = 0; i < property_count; i++) {
> + put_unaligned_be32(property + i, recv);
> + recv += sizeof(property);
> + if (property > TPM2_PROPERTIES_OFFSET) {
> + val = tpm->properties[(property -
> + TPM2_PROPERTIES_OFFSET) + i];
> + } else {
> + switch (property) {
> + case TPM2_PT_PCR_COUNT:
> + val = SANDBOX_TPM_PCR_NB;
> + break;
> + default:
> + val = 0xffffffff;
> + break;
> + }
> + }
> +
> + put_unaligned_be32(val, recv);
> + recv += sizeof(property);
> + }
> + break;
> }
>
> /* Add trailing \0 */
> --
> 2.31.1
>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>