/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __LINUX_TPM_EVENTLOG_H__
#define __LINUX_TPM_EVENTLOG_H__

#include <linux/tpm.h>

#define TCG_EVENT_NAME_LEN_MAX  255
#define MAX_TEXT_EVENT          1000    /* Max event string length */
#define ACPI_TCPA_SIG           "TCPA"  /* 0x41504354 /'TCPA' */

#define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
#define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2

#ifdef CONFIG_PPC64
#define do_endian_conversion(x) be32_to_cpu(x)
#else
#define do_endian_conversion(x) x
#endif

enum bios_platform_class {
        BIOS_CLIENT = 0x00,
        BIOS_SERVER = 0x01,
};

struct tcpa_event {
        u32 pcr_index;
        u32 event_type;
        u8 pcr_value[20];       /* SHA1 */
        u32 event_size;
        u8 event_data[0];
};

enum tcpa_event_types {
        PREBOOT = 0,
        POST_CODE,
        UNUSED,
        NO_ACTION,
        SEPARATOR,
        ACTION,
        EVENT_TAG,
        SCRTM_CONTENTS,
        SCRTM_VERSION,
        CPU_MICROCODE,
        PLATFORM_CONFIG_FLAGS,
        TABLE_OF_DEVICES,
        COMPACT_HASH,
        IPL,
        IPL_PARTITION_DATA,
        NONHOST_CODE,
        NONHOST_CONFIG,
        NONHOST_INFO,
};

struct tcpa_pc_event {
        u32 event_id;
        u32 event_size;
        u8 event_data[0];
};

enum tcpa_pc_event_ids {
        SMBIOS = 1,
        BIS_CERT,
        POST_BIOS_ROM,
        ESCD,
        CMOS,
        NVRAM,
        OPTION_ROM_EXEC,
        OPTION_ROM_CONFIG,
        OPTION_ROM_MICROCODE = 10,
        S_CRTM_VERSION,
        S_CRTM_CONTENTS,
        POST_CONTENTS,
        HOST_TABLE_OF_DEVICES,
};

/* http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/ */

struct tcg_efi_specid_event_algs {
        u16 alg_id;
        u16 digest_size;
} __packed;

struct tcg_efi_specid_event_head {
        u8 signature[16];
        u32 platform_class;
        u8 spec_version_minor;
        u8 spec_version_major;
        u8 spec_errata;
        u8 uintnsize;
        u32 num_algs;
        struct tcg_efi_specid_event_algs digest_sizes[];
} __packed;

struct tcg_pcr_event {
        u32 pcr_idx;
        u32 event_type;
        u8 digest[20];
        u32 event_size;
        u8 event[0];
} __packed;

struct tcg_event_field {
        u32 event_size;
        u8 event[0];
} __packed;

struct tcg_pcr_event2_head {
        u32 pcr_idx;
        u32 event_type;
        u32 count;
        struct tpm_digest digests[];
} __packed;

struct tcg_algorithm_size {
        u16 algorithm_id;
        u16 algorithm_size;
};

struct tcg_algorithm_info {
        u8 signature[16];
        u32 platform_class;
        u8 spec_version_minor;
        u8 spec_version_major;
        u8 spec_errata;
        u8 uintn_size;
        u32 number_of_algorithms;
        struct tcg_algorithm_size digest_sizes[];
};

#ifndef TPM_MEMREMAP
#define TPM_MEMREMAP(start, size) NULL
#endif

#ifndef TPM_MEMUNMAP
#define TPM_MEMUNMAP(start, size) do{} while(0)
#endif

/**
 * __calc_tpm2_event_size - calculate the size of a TPM2 event log entry
 * @event:        Pointer to the event whose size should be calculated
 * @event_header: Pointer to the initial event containing the digest lengths
 * @do_mapping:   Whether or not the event needs to be mapped
 *
 * The TPM2 event log format can contain multiple digests corresponding to
 * separate PCR banks, and also contains a variable length of the data that
 * was measured. This requires knowledge of how long each digest type is,
 * and this information is contained within the first event in the log.
 *
 * We calculate the length by examining the number of events, and then looking
 * at each event in turn to determine how much space is used for events in
 * total. Once we've done this we know the offset of the data length field,
 * and can calculate the total size of the event.
 *
 * Return: size of the event on success, 0 on failure
 */

static inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
                                         struct tcg_pcr_event *event_header,
                                         bool do_mapping)
{
        struct tcg_efi_specid_event_head *efispecid;
        struct tcg_event_field *event_field;
        void *mapping = NULL;
        int mapping_size;
        void *marker;
        void *marker_start;
        u32 halg_size;
        size_t size;
        u16 halg;
        int i;
        int j;
        u32 count, event_type;

        marker = event;
        marker_start = marker;
        marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
                + sizeof(event->count);

        /* Map the event header */
        if (do_mapping) {
                mapping_size = marker - marker_start;
                mapping = TPM_MEMREMAP((unsigned long)marker_start,
                                       mapping_size);
                if (!mapping) {
                        size = 0;
                        goto out;
                }
        } else {
                mapping = marker_start;
        }

        event = (struct tcg_pcr_event2_head *)mapping;
        /*
         * The loop below will unmap these fields if the log is larger than
         * one page, so save them here for reference:
         */
        count = READ_ONCE(event->count);
        event_type = READ_ONCE(event->event_type);

        efispecid = (struct tcg_efi_specid_event_head *)event_header->event;

        /* Check if event is malformed. */
        if (count > efispecid->num_algs) {
                size = 0;
                goto out;
        }

        for (i = 0; i < count; i++) {
                halg_size = sizeof(event->digests[i].alg_id);

                /* Map the digest's algorithm identifier */
                if (do_mapping) {
                        TPM_MEMUNMAP(mapping, mapping_size);
                        mapping_size = halg_size;
                        mapping = TPM_MEMREMAP((unsigned long)marker,
                                             mapping_size);
                        if (!mapping) {
                                size = 0;
                                goto out;
                        }
                } else {
                        mapping = marker;
                }

                memcpy(&halg, mapping, halg_size);
                marker = marker + halg_size;

                for (j = 0; j < efispecid->num_algs; j++) {
                        if (halg == efispecid->digest_sizes[j].alg_id) {
                                marker +=
                                        efispecid->digest_sizes[j].digest_size;
                                break;
                        }
                }
                /* Algorithm without known length. Such event is unparseable. */
                if (j == efispecid->num_algs) {
                        size = 0;
                        goto out;
                }
        }

        /*
         * Map the event size - we don't read from the event itself, so
         * we don't need to map it
         */
        if (do_mapping) {
                TPM_MEMUNMAP(mapping, mapping_size);
                mapping_size += sizeof(event_field->event_size);
                mapping = TPM_MEMREMAP((unsigned long)marker,
                                       mapping_size);
                if (!mapping) {
                        size = 0;
                        goto out;
                }
        } else {
                mapping = marker;
        }

        event_field = (struct tcg_event_field *)mapping;

        marker = marker + sizeof(event_field->event_size)
                + event_field->event_size;
        size = marker - marker_start;

        if (event_type == 0 && event_field->event_size == 0)
                size = 0;

out:
        if (do_mapping)
                TPM_MEMUNMAP(mapping, mapping_size);
        return size;
}

#endif