feat(drtm): add Event Log driver support for DRTM
Added Event Log driver support for DRTM. This driver
is responsible for the doing the hash measurement of
various DRTM components as per [1], and putting these
measurements in the Event Log buffer.
[1]: https://developer.arm.com/documentation/den0113/a, section 3.16
Change-Id: I9892c313cf6640b82e261738116fe00f7975ee12
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/services/std_svc/drtm/drtm_measurements.c b/services/std_svc/drtm/drtm_measurements.c
new file mode 100644
index 0000000..a8f2b32
--- /dev/null
+++ b/services/std_svc/drtm/drtm_measurements.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (c) 2022 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * DRTM measurements into TPM PCRs.
+ *
+ * Authors:
+ * Lucian Paul-Trifu <lucian.paultrifu@gmail.com>
+ *
+ */
+#include <assert.h>
+
+#include <common/debug.h>
+#include <drivers/auth/crypto_mod.h>
+#include <drivers/measured_boot/event_log/event_log.h>
+#include "drtm_main.h"
+#include "drtm_measurements.h"
+#include <lib/xlat_tables/xlat_tables_v2.h>
+
+/* Event Log buffer */
+static uint8_t drtm_event_log[PLAT_DRTM_EVENT_LOG_MAX_SIZE];
+
+/*
+ * Calculate and write hash of various payloads as per DRTM specification
+ * to Event Log.
+ *
+ * @param[in] data_base Address of data
+ * @param[in] data_size Size of data
+ * @param[in] event_type Type of Event
+ * @param[in] event_name Name of the Event
+ * @return:
+ * 0 = success
+ * < 0 = error
+ */
+static int drtm_event_log_measure_and_record(uintptr_t data_base,
+ uint32_t data_size,
+ uint32_t event_type,
+ const char *event_name,
+ unsigned int pcr)
+{
+ int rc;
+ unsigned char hash_data[CRYPTO_MD_MAX_SIZE];
+ event_log_metadata_t metadata = {0};
+
+ metadata.name = event_name;
+ metadata.pcr = pcr;
+
+ /*
+ * Measure the payloads requested by D-CRTM and DCE commponents
+ * Hash algorithm decided by the Event Log driver at build-time
+ */
+ rc = event_log_measure(data_base, data_size, hash_data);
+ if (rc != 0) {
+ return rc;
+ }
+
+ /* Record the mesasurement in the EventLog buffer */
+ event_log_record(hash_data, event_type, &metadata);
+
+ return 0;
+}
+
+/*
+ * Initialise Event Log global variables, used during the recording
+ * of various payload measurements into the Event Log buffer
+ *
+ * @param[in] event_log_start Base address of Event Log buffer
+ * @param[in] event_log_finish End address of Event Log buffer,
+ * it is a first byte past end of the
+ * buffer
+ */
+static void drtm_event_log_init(uint8_t *event_log_start,
+ uint8_t *event_log_finish)
+{
+ event_log_buf_init(event_log_start, event_log_finish);
+ event_log_write_specid_event();
+}
+
+enum drtm_retc drtm_take_measurements(const struct_drtm_dl_args *a)
+{
+ int rc;
+ uintptr_t dlme_img_mapping;
+ uint64_t dlme_img_ep;
+ size_t dlme_img_mapping_bytes;
+ uint8_t drtm_null_data = 0U;
+ uint8_t pcr_schema = DL_ARGS_GET_PCR_SCHEMA(a);
+ const char *drtm_event_arm_sep_data = "ARM_DRTM";
+
+ /* Initialise the EventLog driver */
+ drtm_event_log_init(drtm_event_log, drtm_event_log +
+ sizeof(drtm_event_log));
+
+ /**
+ * Measurements extended into PCR-17.
+ *
+ * PCR-17: Measure the DCE image. Extend digest of (char)0 into PCR-17
+ * since the D-CRTM and the DCE are not separate.
+ */
+ rc = drtm_event_log_measure_and_record((uintptr_t)&drtm_null_data,
+ sizeof(drtm_null_data),
+ DRTM_EVENT_ARM_DCE, NULL,
+ PCR_17);
+ CHECK_RC(rc, drtm_event_log_measure_and_record(DRTM_EVENT_ARM_DCE));
+
+ /* PCR-17: Measure the PCR schema DRTM launch argument. */
+ rc = drtm_event_log_measure_and_record((uintptr_t)&pcr_schema,
+ sizeof(pcr_schema),
+ DRTM_EVENT_ARM_PCR_SCHEMA,
+ NULL, PCR_17);
+ CHECK_RC(rc,
+ drtm_event_log_measure_and_record(DRTM_EVENT_ARM_PCR_SCHEMA));
+
+ /* PCR-17: Measure the enable state of external-debug, and trace. */
+ /*
+ * TODO: Measure the enable state of external-debug and trace. This should
+ * be returned through a platform-specific hook.
+ */
+
+ /* PCR-17: Measure the security lifecycle state. */
+ /*
+ * TODO: Measure the security lifecycle state. This is an implementation-
+ * defined value, retrieved through an implementation-defined mechanisms.
+ */
+
+ /*
+ * PCR-17: Optionally measure the NWd DCE.
+ * It is expected that such subsequent DCE stages are signed and verified.
+ * Whether they are measured in addition to signing is implementation
+ * -defined.
+ * Here the choice is to not measure any NWd DCE, in favour of PCR value
+ * resilience to any NWd DCE updates.
+ */
+
+ /* PCR-17: End of DCE measurements. */
+ rc = drtm_event_log_measure_and_record((uintptr_t)drtm_event_arm_sep_data,
+ strlen(drtm_event_arm_sep_data),
+ DRTM_EVENT_ARM_SEPARATOR, NULL,
+ PCR_17);
+ CHECK_RC(rc, drtm_event_log_measure_and_record(DRTM_EVENT_ARM_SEPARATOR));
+
+ /**
+ * Measurements extended into PCR-18.
+ *
+ * PCR-18: Measure the PCR schema DRTM launch argument.
+ */
+ rc = drtm_event_log_measure_and_record((uintptr_t)&pcr_schema,
+ sizeof(pcr_schema),
+ DRTM_EVENT_ARM_PCR_SCHEMA,
+ NULL, PCR_18);
+ CHECK_RC(rc,
+ drtm_event_log_measure_and_record(DRTM_EVENT_ARM_PCR_SCHEMA));
+
+ /*
+ * PCR-18: Measure the public key used to verify DCE image(s) signatures.
+ * Extend digest of (char)0, since we do not expect the NWd DCE to be
+ * present.
+ */
+ assert(a->dce_nwd_size == 0);
+ rc = drtm_event_log_measure_and_record((uintptr_t)&drtm_null_data,
+ sizeof(drtm_null_data),
+ DRTM_EVENT_ARM_DCE_PUBKEY,
+ NULL, PCR_18);
+ CHECK_RC(rc,
+ drtm_event_log_measure_and_record(DRTM_EVENT_ARM_DCE_PUBKEY));
+
+ /* PCR-18: Measure the DLME image. */
+ dlme_img_mapping_bytes = page_align(a->dlme_img_size, UP);
+ rc = mmap_add_dynamic_region_alloc_va(a->dlme_paddr + a->dlme_img_off,
+ &dlme_img_mapping,
+ dlme_img_mapping_bytes, MT_RO_DATA | MT_NS);
+ if (rc) {
+ WARN("DRTM: %s: mmap_add_dynamic_region() failed rc=%d\n",
+ __func__, rc);
+ return INTERNAL_ERROR;
+ }
+
+ rc = drtm_event_log_measure_and_record(dlme_img_mapping, a->dlme_img_size,
+ DRTM_EVENT_ARM_DLME, NULL,
+ PCR_18);
+ CHECK_RC(rc, drtm_event_log_measure_and_record(DRTM_EVENT_ARM_DLME));
+
+ rc = mmap_remove_dynamic_region(dlme_img_mapping, dlme_img_mapping_bytes);
+ CHECK_RC(rc, mmap_remove_dynamic_region);
+
+ /* PCR-18: Measure the DLME image entry point. */
+ dlme_img_ep = DL_ARGS_GET_DLME_ENTRY_POINT(a);
+ drtm_event_log_measure_and_record((uintptr_t)&dlme_img_ep,
+ sizeof(dlme_img_ep),
+ DRTM_EVENT_ARM_DLME_EP, NULL,
+ PCR_18);
+ CHECK_RC(rc, drtm_event_log_measure_and_record(DRTM_EVENT_ARM_DLME_EP));
+
+ /* PCR-18: End of DCE measurements. */
+ rc = drtm_event_log_measure_and_record((uintptr_t)drtm_event_arm_sep_data,
+ strlen(drtm_event_arm_sep_data),
+ DRTM_EVENT_ARM_SEPARATOR, NULL,
+ PCR_18);
+ CHECK_RC(rc,
+ drtm_event_log_measure_and_record(DRTM_EVENT_ARM_SEPARATOR));
+ /*
+ * If the DCE is unable to log a measurement because there is no available
+ * space in the event log region, the DCE must extend a hash of the value
+ * 0xFF (1 byte in size) into PCR[17] and PCR[18] and enter remediation.
+ */
+
+ return SUCCESS;
+}
+
+void drtm_serialise_event_log(uint8_t *dst, size_t *event_log_size_out)
+{
+ *event_log_size_out = event_log_get_cur_size(drtm_event_log);
+ memcpy(dst, drtm_event_log, *event_log_size_out);
+}