[PATCH v6 2/6] tpm: sandbox: Update for needed TPM2 capabilities

[Eddie James]

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.
Remove the !SANDBOX dependency for EFI TCG2 as well.

Signed-off-by: Eddie James <eajames at linux.ibm.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
Changes since v5:
 - Remove the !SANDBOX dependency for EFI TCG2

 drivers/tpm/tpm2_tis_sandbox.c | 100 ++++++++++++++++++++++++---------
 lib/efi_loader/Kconfig         |   2 -
 2 files changed, 72 insertions(+), 30 deletions(-)

diff --git a/drivers/tpm/tpm2_tis_sandbox.c b/drivers/tpm/tpm2_tis_sandbox.c
index e4004cfcca..f63c72814f 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 */
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index c5835e6ef6..605719d2b6 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -333,8 +333,6 @@ config EFI_TCG2_PROTOCOL
 	bool "EFI_TCG2_PROTOCOL support"
 	default y
 	depends on TPM_V2
-	# Sandbox TPM currently fails on GetCapabilities needed for TCG2
-	depends on !SANDBOX
 	select SHA1
 	select SHA256
 	select SHA384
-- 
2.31.1