feat: extract standalone Event Log library
Extract the Event Log driver from TF-A into its own `libevlog` project.
Add a CMake-based build to support initialization, measurement,
recording, and dumping of TCG event logs across projects
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
Change-Id: I44dce25b3d67db94e5e0774174967433c2a5a377
diff --git a/include/event_log.h b/include/event_log.h
new file mode 100644
index 0000000..f97c580
--- /dev/null
+++ b/include/event_log.h
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2020-2025, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef EVENT_LOG_H
+#define EVENT_LOG_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <tcg.h>
+
+/* Number of hashing algorithms supported */
+#define HASH_ALG_COUNT 1U
+
+#define EVLOG_INVALID_ID UINT32_MAX
+
+/* Maximum digest size based on the strongest hash algorithm i.e. SHA-512. */
+#define MAX_DIGEST_SIZE 64U
+
+#define MEMBER_SIZE(type, member) sizeof(((type *)0)->member)
+
+typedef struct {
+ unsigned int id;
+ const char *name;
+ unsigned int pcr;
+} event_log_metadata_t;
+
+typedef int (*evlog_hash_func_t)(uint32_t alg, void *data, unsigned int len,
+ uint8_t *digest);
+
+struct event_log_hash_info {
+ evlog_hash_func_t func;
+ const uint32_t *ids;
+ size_t count;
+};
+
+#define ID_EVENT_SIZE \
+ (sizeof(id_event_headers_t) + \
+ (sizeof(id_event_algorithm_size_t) * HASH_ALG_COUNT) + \
+ sizeof(id_event_struct_data_t))
+
+#define LOC_EVENT_SIZE \
+ (sizeof(event2_header_t) + sizeof(tpmt_ha) + TCG_DIGEST_SIZE + \
+ sizeof(event2_data_t) + sizeof(startup_locality_event_t))
+
+#define LOG_MIN_SIZE (ID_EVENT_SIZE + LOC_EVENT_SIZE)
+
+#define EVENT2_HDR_SIZE \
+ (sizeof(event2_header_t) + sizeof(tpmt_ha) + TCG_DIGEST_SIZE + \
+ sizeof(event2_data_t))
+
+/* Functions' declarations */
+
+/**
+ * Initialize the Event Log buffer.
+ *
+ * Sets global pointers to manage the Event Log memory region,
+ * allowing subsequent log operations to write into the buffer.
+ *
+ * @param[in] start Pointer to the start of the Event Log buffer.
+ * @param[in] finish Pointer to the end of the buffer
+ * (i.e., one byte past the last valid address).
+ *
+ * @return 0 on success, or -EINVAL if the input range is invalid.
+ */
+int event_log_buf_init(uint8_t *start, uint8_t *finish);
+
+/**
+ * Dump the contents of the Event Log.
+ *
+ * Outputs the raw contents of the Event Log buffer, typically
+ * for debugging or audit purposes.
+ *
+ * @param[in] log_addr Pointer to the start of the Event Log buffer.
+ * @param[in] log_size Size of the Event Log buffer in bytes.
+ *
+ * @return 0 on success, or a negative error code on failure.
+ */
+int event_log_dump(uint8_t *log_addr, size_t log_size);
+
+/**
+ * Initialize the Event Log subsystem.
+ *
+ * Wrapper around `event_log_buf_init()` to configure the memory range
+ * for the Event Log buffer.
+ *
+ * @param[in] start Pointer to the start of the Event Log buffer.
+ * @param[in] finish Pointer to the end of the buffer
+ * (i.e., one byte past the last valid address).
+ *
+ * @return 0 on success, or a negative error code on failure.
+ */
+int event_log_init(uint8_t *start, uint8_t *finish);
+
+/**
+ * Initialize the Event Log and register supported hash functions.
+ *
+ * Initializes the Event Log subsystem using the provided memory region
+ * and registers one or more cryptographic hash functions for use in
+ * event measurements. This function must be called before any measurements
+ * or event recording can take place.
+ *
+ * @param[in] start Pointer to the beginning of the Event Log buffer.
+ * @param[in] finish Pointer to the end of the Event Log buffer.
+ * @param[in] hash_info Pointer to a structure containing the hash function
+ * pointer and associated algorithm identifiers.
+ *
+ * @return 0 on success,
+ * -EEXIST if hash functions have already been registered,
+ * -EINVAL if the input parameters are invalid,
+ * or a negative error code from the underlying initialization logic.
+ */
+int event_log_init_and_reg(uint8_t *start, uint8_t *finish,
+ const struct event_log_hash_info *hash_info);
+
+/**
+ * Measure input data and log its hash to the Event Log.
+ *
+ * Computes the cryptographic hash of the specified data and records it
+ * in the Event Log as a TCG_PCR_EVENT2 structure using event type EV_POST_CODE.
+ * Useful for firmware or image attestation.
+ *
+ * @param[in] data_base Pointer to the base of the data to be measured.
+ * @param[in] data_size Size of the data in bytes.
+ * @param[in] data_id Identifier used to match against metadata.
+ * @param[in] metadata_ptr Pointer to an array of event_log_metadata_t.
+ *
+ * @return 0 on success, or a negative error code on failure.
+ */
+int event_log_measure_and_record(uintptr_t data_base, uint32_t data_size,
+ uint32_t data_id,
+ const event_log_metadata_t *metadata_ptr);
+
+/**
+ * Measure the input data and return its hash.
+ *
+ * Computes the cryptographic hash of the specified memory region using
+ * the default hashing algorithm configured in the Event Log subsystem.
+ *
+ * @param[in] data_base Pointer to the base of the data to be measured.
+ * @param[in] data_size Size of the data in bytes.
+ * @param[out] hash_data Buffer to hold the resulting hash output
+ * (must be at least CRYPTO_MD_MAX_SIZE bytes).
+ *
+ * @return 0 on success, or an error code on failure.
+ */
+int event_log_measure(uintptr_t data_base, uint32_t data_size,
+ unsigned char *hash_data);
+
+/**
+ * Record a measurement event in the Event Log.
+ *
+ * Writes a TCG_PCR_EVENT2 structure to the Event Log using the
+ * provided hash and metadata. This function assumes the buffer
+ * has enough space and that `event_log_buf_init()` has been called.
+ *
+ * @param[in] hash Pointer to the digest (TCG_DIGEST_SIZE bytes).
+ * @param[in] event_type Type of the event, as defined in tcg.h.
+ * @param[in] metadata_ptr Pointer to an event_log_metadata_t structure
+ * providing event-specific context (e.g., PCR index, name).
+ *
+ * @return 0 on success, or -ENOMEM if the buffer has insufficient space.
+ */
+int event_log_record(const uint8_t *hash, uint32_t event_type,
+ const event_log_metadata_t *metadata_ptr);
+
+/**
+ * Initialize the Event Log with mandatory header events.
+ *
+ * Writes the Specification ID (SpecID) and Startup Locality events
+ * as required by the TCG PC Client Platform Firmware Profile.
+ * These must be the first entries in the Event Log.
+ *
+ * @return 0 on success, or a negative error code on failure.
+ */
+int event_log_write_header(void);
+
+/**
+ * Write the SpecID event to the Event Log.
+ *
+ * Records the TCG_EfiSpecIDEventStruct to declare the structure
+ * and supported algorithms of the Event Log format.
+ *
+ * @return 0 on success, or a negative error code on failure.
+ */
+int event_log_write_specid_event(void);
+
+/**
+ * Get the current size of the Event Log.
+ *
+ * Calculates how many bytes of the Event Log buffer have been used,
+ * based on the current log pointer and the start of the buffer.
+ *
+ * @param[in] start Pointer to the start of the Event Log buffer.
+ *
+ * @return The number of bytes currently used in the Event Log.
+ */
+size_t event_log_get_cur_size(uint8_t *start);
+
+#endif /* EVENT_LOG_H */
diff --git a/include/sha_common_macros.h b/include/sha_common_macros.h
new file mode 100644
index 0000000..e90552f
--- /dev/null
+++ b/include/sha_common_macros.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2024, NVIDIA Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SHA_COMMON_MACROS_H
+#define SHA_COMMON_MACROS_H
+
+#define MD5_DIGEST_SIZE 16U
+#define SHA1_DIGEST_SIZE 20U
+#define SHA224_DIGEST_SIZE 28U
+#define SHA256_DIGEST_SIZE 32U
+#define SHA384_DIGEST_SIZE 48U
+#define SHA512_224_DIGEST_SIZE 28U
+#define SHA512_256_DIGEST_SIZE 32U
+#define SHA512_DIGEST_SIZE 64U
+
+#endif /* SHA_COMMON_MACROS_H */
diff --git a/include/tcg.h b/include/tcg.h
new file mode 100644
index 0000000..c9bb341
--- /dev/null
+++ b/include/tcg.h
@@ -0,0 +1,304 @@
+/*
+ * Copyright (c) 2020-2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef TCG_H
+#define TCG_H
+
+#include <sha_common_macros.h>
+#include <stdint.h>
+
+#define TCG_ID_EVENT_SIGNATURE_03 "Spec ID Event03"
+#define TCG_STARTUP_LOCALITY_SIGNATURE "StartupLocality"
+
+#define TCG_SPEC_VERSION_MAJOR_TPM2 2
+#define TCG_SPEC_VERSION_MINOR_TPM2 0
+#define TCG_SPEC_ERRATA_TPM2 2
+
+/*
+ * Event types
+ * Ref. Table 9 Events
+ * TCG PC Client Platform Firmware Profile Specification.
+ */
+#define EV_PREBOOT_CERT 0x00000000U
+#define EV_POST_CODE 0x00000001U
+#define EV_UNUSED 0x00000002U
+#define EV_NO_ACTION 0x00000003U
+#define EV_SEPARATOR 0x00000004U
+#define EV_ACTION 0x00000005U
+#define EV_EVENT_TAG 0x00000006U
+#define EV_S_CRTM_CONTENTS 0x00000007U
+#define EV_S_CRTM_VERSION 0x00000008U
+#define EV_CPU_MICROCODE 0x00000009U
+#define EV_PLATFORM_CONFIG_FLAGS 0x0000000AU
+#define EV_TABLE_OF_DEVICES 0x0000000BU
+#define EV_COMPACT_HASH 0x0000000CU
+#define EV_IPL 0x0000000DU
+#define EV_IPL_PARTITION_DATA 0x0000000EU
+#define EV_NONHOST_CODE 0x0000000FU
+#define EV_NONHOST_CONFIG 0x00000010U
+#define EV_NONHOST_INFO 0x00000011U
+#define EV_OMIT_BOOT_DEVICE_EVENTS 0x00000012U
+#define EV_EFI_EVENT_BASE 0x80000000U
+#define EV_EFI_VARIABLE_DRIVER_CONFIG 0x80000001U
+#define EV_EFI_VARIABLE_BOOT 0x80000002U
+#define EV_EFI_BOOT_SERVICES_APPLICATION 0x80000003U
+#define EV_EFI_BOOT_SERVICES_DRIVER 0x80000004U
+#define EV_EFI_RUNTIME_SERVICES_DRIVER 0x80000005U
+#define EV_EFI_GPT_EVENT 0x80000006U
+#define EV_EFI_ACTION 0x80000007U
+#define EV_EFI_PLATFORM_FIRMWARE_BLOB 0x80000008U
+#define EV_EFI_HANDOFF_TABLES 0x80000009U
+#define EV_EFI_HCRTM_EVENT 0x80000010U
+#define EV_EFI_VARIABLE_AUTHORITY 0x800000E0U
+
+/*
+ * TPM_ALG_ID constants.
+ * Ref. Table 9 - Definition of (UINT16) TPM_ALG_ID Constants
+ * Trusted Platform Module Library. Part 2: Structures
+ */
+#define TPM_ALG_SHA256 0x000B
+#define TPM_ALG_SHA384 0x000C
+#define TPM_ALG_SHA512 0x000D
+
+/* TCG Platform Type */
+#define PLATFORM_CLASS_CLIENT 0
+#define PLATFORM_CLASS_SERVER 1
+
+enum {
+ /*
+ * SRTM, BIOS, Host Platform Extensions, Embedded
+ * Option ROMs and PI Drivers
+ */
+ PCR_0 = 0,
+ /* Host Platform Configuration */
+ PCR_1,
+ /* UEFI driver and application Code */
+ PCR_2,
+ /* UEFI driver and application Configuration and Data */
+ PCR_3,
+ /* UEFI Boot Manager Code (usually the MBR) and Boot Attempts */
+ PCR_4,
+ /*
+ * Boot Manager Code Configuration and Data (for use
+ * by the Boot Manager Code) and GPT/Partition Table
+ */
+ PCR_5,
+ /* Host Platform Manufacturer Specific */
+ PCR_6,
+ /* Secure Boot Policy */
+ PCR_7,
+ /* 8-15: Defined for use by the Static OS */
+ PCR_8,
+ /* Debug */
+ PCR_16 = 16,
+
+ /* D-CRTM-measurements by DRTM implementation */
+ PCR_17 = 17,
+ /* DCE measurements by DRTM implementation */
+ PCR_18 = 18
+};
+
+#pragma pack(push, 1)
+
+/*
+ * PCR Event Header
+ * TCG EFI Protocol Specification
+ * 5.3 Event Log Header
+ */
+typedef struct {
+ /* PCRIndex:
+ * The PCR Index to which this event is extended
+ */
+ uint32_t pcr_index;
+
+ /* EventType:
+ * SHALL be an EV_NO_ACTION event
+ */
+ uint32_t event_type;
+
+ /* SHALL be 20 Bytes of 0x00 */
+ uint8_t digest[SHA1_DIGEST_SIZE];
+
+ /* The size of the event */
+ uint32_t event_size;
+
+ /* SHALL be a TCG_EfiSpecIdEvent */
+ uint8_t event[]; /* [event_data_size] */
+} tcg_pcr_event_t;
+
+/*
+ * Log Header Entry Data
+ * Ref. Table 14 TCG_EfiSpecIdEventAlgorithmSize
+ * TCG PC Client Platform Firmware Profile 9.4.5.1
+ */
+typedef struct {
+ /* Algorithm ID (hashAlg) of the Hash used by BIOS */
+ uint16_t algorithm_id;
+
+ /* The size of the digest produced by the implemented Hash algorithm */
+ uint16_t digest_size;
+} id_event_algorithm_size_t;
+
+/*
+ * TCG_EfiSpecIdEvent structure
+ * Ref. Table 15 TCG_EfiSpecIdEvent
+ * TCG PC Client Platform Firmware Profile 9.4.5.1
+ */
+typedef struct {
+ /*
+ * The NUL-terminated ASCII string "Spec ID Event03".
+ * SHALL be set to {0x53, 0x70, 0x65, 0x63, 0x20, 0x49, 0x44,
+ * 0x20, 0x45, 0x76, 0x65, 0x6e, 0x74, 0x30, 0x33, 0x00}.
+ */
+ uint8_t signature[16];
+
+ /*
+ * The value for the Platform Class.
+ * The enumeration is defined in the TCG ACPI Specification Client
+ * Common Header.
+ */
+ uint32_t platform_class;
+
+ /*
+ * The PC Client Platform Profile Specification minor version number
+ * this BIOS supports.
+ * Any BIOS supporting this version (2.0) MUST set this value to 0x00.
+ */
+ uint8_t spec_version_minor;
+
+ /*
+ * The PC Client Platform Profile Specification major version number
+ * this BIOS supports.
+ * Any BIOS supporting this version (2.0) MUST set this value to 0x02.
+ */
+ uint8_t spec_version_major;
+
+ /*
+ * The PC Client Platform Profile Specification errata version number
+ * this BIOS supports.
+ * Any BIOS supporting this version (2.0) MUST set this value to 0x02.
+ */
+ uint8_t spec_errata;
+
+ /*
+ * Specifies the size of the UINTN fields used in various data
+ * structures used in this specification.
+ * 0x01 indicates UINT32 and 0x02 indicates UINT64.
+ */
+ uint8_t uintn_size;
+
+ /*
+ * The number of Hash algorithms in the digestSizes field.
+ * This field MUST be set to a value of 0x01 or greater.
+ */
+ uint32_t number_of_algorithms;
+
+ /*
+ * Each TCG_EfiSpecIdEventAlgorithmSize SHALL contain an algorithmId
+ * and digestSize for each hash algorithm used in the TCG_PCR_EVENT2
+ * structure, the first of which is a Hash algorithmID and the second
+ * is the size of the respective digest.
+ */
+ id_event_algorithm_size_t digest_size[]; /* number_of_algorithms */
+} id_event_struct_header_t;
+
+typedef struct {
+ /*
+ * Size in bytes of the VendorInfo field.
+ * Maximum value MUST be FFh bytes.
+ */
+ uint8_t vendor_info_size;
+
+ /*
+ * Provided for use by Platform Firmware implementer. The value might
+ * be used, for example, to provide more detailed information about the
+ * specific BIOS such as BIOS revision numbers, etc. The values within
+ * this field are not standardized and are implementer-specific.
+ * Platform-specific or -unique information MUST NOT be provided in
+ * this field.
+ *
+ */
+ uint8_t vendor_info[]; /* [vendorInfoSize] */
+} id_event_struct_data_t;
+
+typedef struct {
+ id_event_struct_header_t struct_header;
+ id_event_struct_data_t struct_data;
+} id_event_struct_t;
+
+typedef struct {
+ tcg_pcr_event_t header;
+ id_event_struct_header_t struct_header;
+} id_event_headers_t;
+
+/* TPMT_HA Structure */
+typedef struct {
+ /* Selector of the hash contained in the digest that implies
+ * the size of the digest
+ */
+ uint16_t algorithm_id; /* AlgorithmId */
+
+ /* Digest, depends on AlgorithmId */
+ uint8_t digest[]; /* Digest[] */
+} tpmt_ha;
+
+/*
+ * TPML_DIGEST_VALUES Structure
+ */
+typedef struct {
+ /* The number of digests in the list */
+ uint32_t count; /* Count */
+
+ /* The list of tagged digests, as sent to the TPM as part of a
+ * TPM2_PCR_Extend or as received from a TPM2_PCR_Event command
+ */
+ tpmt_ha digests[]; /* Digests[Count] */
+} tpml_digest_values;
+
+/*
+ * TCG_PCR_EVENT2 header
+ */
+typedef struct {
+ /* The PCR Index to which this event was extended */
+ uint32_t pcr_index; /* PCRIndex */
+
+ /* Type of event */
+ uint32_t event_type; /* EventType */
+
+ /* Digests:
+ * A counted list of tagged digests, which contain the digest of
+ * the event data (or external data) for all active PCR banks
+ */
+ tpml_digest_values digests; /* Digests */
+} event2_header_t;
+
+typedef struct event2_data {
+ /* The size of the event data */
+ uint32_t event_size; /* EventSize */
+
+ /* The data of the event */
+ uint8_t event[]; /* Event[EventSize] */
+} event2_data_t;
+
+/*
+ * Startup Locality Event
+ * Ref. TCG PC Client Platform Firmware Profile 9.4.5.3
+ */
+typedef struct {
+ /*
+ * The NUL-terminated ASCII string "StartupLocality" SHALL be
+ * set to {0x53 0x74 0x61 0x72 0x74 0x75 0x70 0x4C 0x6F 0x63
+ * 0x61 0x6C 0x69 0x74 0x79 0x00}
+ */
+ uint8_t signature[16];
+
+ /* The Locality Indicator which sent the TPM2_Startup command */
+ uint8_t startup_locality;
+} startup_locality_event_t;
+
+#pragma pack(pop)
+
+#endif /* TCG_H */