1 files changed, 127 insertions, 0 deletions
diff --git a/tpm.c b/tpm.c
new file mode 100644
index 00000000..71bcf9b9
--- /dev/null
+++ b/tpm.c
@@ -0,0 +1,127 @@
+#include <efi.h>
+#include <efilib.h>
+#include <string.h>
+
+#include "tpm.h"
+
+extern UINT8 in_protocol;
+
+#define perror(fmt, ...) ({                                             \
+			UINTN __perror_ret = 0;                               \
+			if (!in_protocol)                                     \
+				__perror_ret = Print((fmt), ##__VA_ARGS__);   \
+			__perror_ret;                                         \
+		})
+
+
+EFI_GUID tpm_guid = EFI_TPM_GUID;
+EFI_GUID tpm2_guid = EFI_TPM2_GUID;
+
+static BOOLEAN tpm_present(efi_tpm_protocol_t *tpm)
+{
+	EFI_STATUS status;
+	TCG_EFI_BOOT_SERVICE_CAPABILITY caps;
+	UINT32 flags;
+	EFI_PHYSICAL_ADDRESS eventlog, lastevent;
+
+	caps.Size = (UINT8)sizeof(caps);
+	status = uefi_call_wrapper(tpm->status_check, 5, tpm, &caps, &flags,
+				   &eventlog, &lastevent);
+
+	if (status != EFI_SUCCESS || caps.TPMDeactivatedFlag
+	    || !caps.TPMPresentFlag)
+		return FALSE;
+
+	return TRUE;
+}
+
+static BOOLEAN tpm2_present(efi_tpm2_protocol_t *tpm)
+{
+	EFI_STATUS status;
+	EFI_TCG2_BOOT_SERVICE_CAPABILITY caps;
+	EFI_TCG2_BOOT_SERVICE_CAPABILITY_1_0 *caps_1_0;
+
+	caps.Size = (UINT8)sizeof(caps);
+
+	status = uefi_call_wrapper(tpm->get_capability, 2, tpm, &caps);
+
+	if (status != EFI_SUCCESS)
+		return FALSE;
+
+	if (caps.StructureVersion.Major == 1 &&
+	    caps.StructureVersion.Minor == 0) {
+		caps_1_0 = (EFI_TCG2_BOOT_SERVICE_CAPABILITY_1_0 *)&caps;
+		if (caps_1_0->TPMPresentFlag)
+			return TRUE;
+	} else {
+		if (caps.TPMPresentFlag)
+			return TRUE;
+	}
+
+	return FALSE;
+}
+
+EFI_STATUS tpm_log_event(EFI_PHYSICAL_ADDRESS buf, UINTN size, UINT8 pcr,
+			 const CHAR8 *description)
+{
+	EFI_STATUS status;
+	efi_tpm_protocol_t *tpm;
+	efi_tpm2_protocol_t *tpm2;
+
+	status = LibLocateProtocol(&tpm2_guid, (VOID **)&tpm2);
+	/* TPM 2.0 */
+	if (status == EFI_SUCCESS) {
+		EFI_TCG2_EVENT *event;
+
+		if (!tpm2_present(tpm2))
+			return EFI_SUCCESS;
+
+		event = AllocatePool(sizeof(*event) + strlen(description) + 1);
+		if (!event) {
+			perror(L"Unable to allocate event structure\n");
+			return EFI_OUT_OF_RESOURCES;
+		}
+
+		event->Header.HeaderSize = sizeof(EFI_TCG2_EVENT_HEADER);
+		event->Header.HeaderVersion = 1;
+		event->Header.PCRIndex = pcr;
+		event->Header.EventType = 0x0d;
+		event->Size = sizeof(*event) - sizeof(event->Event) + strlen(description) + 1;
+		memcpy(event->Event, description, strlen(description) + 1);
+		status = uefi_call_wrapper(tpm2->hash_log_extend_event, 5, tpm2,
+					   0, buf, (UINT64) size, event);
+		FreePool(event);
+		return status;
+	} else {
+		TCG_PCR_EVENT *event;
+		UINT32 algorithm, eventnum = 0;
+		EFI_PHYSICAL_ADDRESS lastevent;
+
+		status = LibLocateProtocol(&tpm_guid, (VOID **)&tpm);
+
+		if (status != EFI_SUCCESS)
+			return EFI_SUCCESS;
+
+		if (!tpm_present(tpm))
+			return EFI_SUCCESS;
+
+		event = AllocatePool(sizeof(*event) + strlen(description) + 1);
+
+		if (!event) {
+			perror(L"Unable to allocate event structure\n");
+			return EFI_OUT_OF_RESOURCES;
+		}
+
+		event->PCRIndex = pcr;
+		event->EventType = 0x0d;
+		event->EventSize = strlen(description) + 1;
+		algorithm = 0x00000004;
+		status = uefi_call_wrapper(tpm->log_extend_event, 7, tpm, buf,
+					   (UINT64)size, algorithm, event,
+					   &eventnum, &lastevent);
+		FreePool(event);
+		return status;
+	}
+
+	return EFI_SUCCESS;
+}