[RFC PATCH 06/12] x86: Add early general TPM interface support for Secure Launch

[Ross Philipson]

From: "Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>

This commit exposes a minimal general interface for the compressed
kernel to request the required TPM operations to send measurements to
a TPM.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
 arch/x86/boot/compressed/Makefile  |   2 +-
 arch/x86/boot/compressed/tpm/tpm.c | 190 +++++++++++++++++++++++++++++
 2 files changed, 191 insertions(+), 1 deletion(-)
 create mode 100644 arch/x86/boot/compressed/tpm/tpm.c

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 6c2beb306631..922223948499 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -98,7 +98,7 @@ vmlinux-objs-$(CONFIG_SECURE_LAUNCH_SHA256) += $(obj)/early_sha256.o
 vmlinux-objs-$(CONFIG_SECURE_LAUNCH_SHA512) += $(obj)/early_sha512.o
 vmlinux-objs-$(CONFIG_SECURE_LAUNCH) += $(obj)/tpm/tpmio.o $(obj)/tpm/tpm_buff.o \
 	$(obj)/tpm/tis.o $(obj)/tpm/crb.o $(obj)/tpm/tpm1_cmds.o \
-	$(obj)/tpm/tpm2_cmds.o $(obj)/tpm/tpm2_auth.o
+	$(obj)/tpm/tpm2_cmds.o $(obj)/tpm/tpm2_auth.o $(obj)/tpm/tpm.o
 
 # The compressed kernel is built with -fPIC/-fPIE so that a boot loader
 # can place it anywhere in memory and it will still run. However, since
diff --git a/arch/x86/boot/compressed/tpm/tpm.c b/arch/x86/boot/compressed/tpm/tpm.c
new file mode 100644
index 000000000000..85923d54dc04
--- /dev/null
+++ b/arch/x86/boot/compressed/tpm/tpm.c
@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2019 Apertus Solutions, LLC
+ *
+ * Author(s):
+ *      Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include "tpm.h"
+#include "tpmbuff.h"
+#include "tis.h"
+#include "crb.h"
+#include "tpm_common.h"
+#include "tpm1.h"
+#include "tpm2.h"
+#include "tpm2_constants.h"
+
+static struct tpm tpm;
+
+static void find_interface_and_family(struct tpm *t)
+{
+	struct tpm_interface_id intf_id;
+	struct tpm_intf_capability intf_cap;
+
+	/* Sort out whether if it is 1.2 */
+	intf_cap.val = tpm_read32(TPM_INTF_CAPABILITY_0);
+	if ((intf_cap.interface_version == TPM12_TIS_INTF_12) ||
+	    (intf_cap.interface_version == TPM12_TIS_INTF_13)) {
+		t->family = TPM12;
+		t->intf = TPM_TIS;
+		return;
+	}
+
+	/* Assume that it is 2.0 and TIS */
+	t->family = TPM20;
+	t->intf = TPM_TIS;
+
+	/* Check if the interface is CRB */
+	intf_id.val = tpm_read32(TPM_INTERFACE_ID_0);
+	if (intf_id.interface_type == TPM_CRB_INTF_ACTIVE)
+		t->intf = TPM_CRB;
+}
+
+struct tpm *enable_tpm(void)
+{
+	struct tpm *t = &tpm;
+
+	find_interface_and_family(t);
+
+	switch (t->intf) {
+	case TPM_DEVNODE:
+		/* Not implemented yet */
+		break;
+	case TPM_TIS:
+		if (!tis_init(t))
+			goto err;
+		break;
+	case TPM_CRB:
+		if (!crb_init(t))
+			goto err;
+		break;
+	case TPM_UEFI:
+		/* Not implemented yet */
+		break;
+	}
+
+	/* TODO: ACPI TPM discovery */
+
+	return t;
+
+err:
+	return NULL;
+}
+
+u8 tpm_request_locality(struct tpm *t, u8 l)
+{
+	u8 ret = TPM_NO_LOCALITY;
+
+	switch (t->intf) {
+	case TPM_DEVNODE:
+		/* Not implemented yet */
+		break;
+	case TPM_TIS:
+		ret = tis_request_locality(l);
+		break;
+	case TPM_CRB:
+		ret = crb_request_locality(l);
+		break;
+	case TPM_UEFI:
+		/* Not implemented yet */
+		break;
+	}
+
+	if (ret < TPM_MAX_LOCALITY)
+		t->buff = alloc_tpmbuff(t->intf, ret);
+
+	return ret;
+}
+
+void tpm_relinquish_locality(struct tpm *t)
+{
+	switch (t->intf) {
+	case TPM_DEVNODE:
+		/* Not implemented yet */
+		break;
+	case TPM_TIS:
+		tis_relinquish_locality();
+		break;
+	case TPM_CRB:
+		crb_relinquish_locality();
+		break;
+	case TPM_UEFI:
+		/* Not implemented yet */
+		break;
+	}
+
+	free_tpmbuff(t->buff, t->intf);
+}
+
+#define MAX_TPM_EXTEND_SIZE 70 /* TPM2 SHA512 is the largest */
+int tpm_extend_pcr(struct tpm *t, u32 pcr, u16 algo,
+		u8 *digest)
+{
+	int ret = 0;
+
+	if (t->buff == NULL) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (t->family == TPM12) {
+		struct tpm_digest d;
+
+		if (algo != TPM_ALG_SHA1) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		d.pcr = pcr;
+		memcpy((void *)d.digest.sha1.digest,
+			digest, SHA1_DIGEST_SIZE);
+
+		ret = tpm1_pcr_extend(t, &d);
+	} else if (t->family == TPM20) {
+		struct tpml_digest_values *d;
+		u8 buf[MAX_TPM_EXTEND_SIZE];
+
+		d = (struct tpml_digest_values *) buf;
+		d->count = 1;
+		switch (algo) {
+		case TPM_ALG_SHA1:
+			d->digests->alg = TPM_ALG_SHA1;
+			memcpy(d->digests->digest, digest, SHA1_SIZE);
+			break;
+		case TPM_ALG_SHA256:
+			d->digests->alg = TPM_ALG_SHA256;
+			memcpy(d->digests->digest, digest, SHA256_SIZE);
+			break;
+		case TPM_ALG_SHA384:
+			d->digests->alg = TPM_ALG_SHA384;
+			memcpy(d->digests->digest, digest, SHA384_SIZE);
+			break;
+		case TPM_ALG_SHA512:
+			d->digests->alg = TPM_ALG_SHA512;
+			memcpy(d->digests->digest, digest, SHA512_SIZE);
+			break;
+		case TPM_ALG_SM3_256:
+			d->digests->alg = TPM_ALG_SM3_256;
+			memcpy(d->digests->digest, digest, SM3256_SIZE);
+			break;
+		default:
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ret = tpm2_extend_pcr(t, pcr, d);
+	} else {
+		ret = -EINVAL;
+	}
+out:
+	return ret;
+}
+
+void free_tpm(struct tpm *t)
+{
+	tpm_relinquish_locality(t);
+}
-- 
2.25.1