/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <unistd.h>

#include "alloc-util.h"

#include "dirent-util.h"

#include "efi-api.h"

#include "efi.h"

#include "efivars.h"

#include "fd-util.h"

#include "fileio.h"

#include "log.h"

#include "parse-util.h"

#include "sort-util.h"

#include "stat-util.h"

#include "stdio-util.h"

#include "string-util.h"

#include "tpm2-util.h"                  /* IWYU pragma: keep */

#include "utf8.h"

#define EFI_TCG2_BOOT_HASH_ALG_SHA1   0x01

#define EFI_TCG2_BOOT_HASH_ALG_SHA256 0x02

#define EFI_TCG2_BOOT_HASH_ALG_SHA384 0x04

#define EFI_TCG2_BOOT_HASH_ALG_SHA512 0x08

#define LOAD_OPTION_ACTIVE            0x00000001

#define MEDIA_DEVICE_PATH                   0x04

#define MEDIA_HARDDRIVE_DP                  0x01

#define MEDIA_FILEPATH_DP                   0x04

#define SIGNATURE_TYPE_GUID                 0x02

#define MBR_TYPE_EFI_PARTITION_TABLE_HEADER 0x02

#define END_DEVICE_PATH_TYPE                0x7f

#define END_ENTIRE_DEVICE_PATH_SUBTYPE      0xff

#define EFI_OS_INDICATIONS_BOOT_TO_FW_UI UINT64_C(0x0000000000000001)

#define boot_option__contents                   \

        {                                       \

                uint32_t attr;                  \

                uint16_t path_len;              \

                uint16_t title[];               \

        }

struct boot_option boot_option__contents;

struct boot_option__packed boot_option__contents _packed_;

assert_cc(offsetof(struct boot_option, title) == offsetof(struct boot_option__packed, title));

/* sizeof(struct boot_option) != sizeof(struct boot_option__packed), so

 * the *size* of the structure should not be used anywhere below. */

struct drive_path {

        uint32_t part_nr;

        uint64_t part_start;

        uint64_t part_size;

        char signature[16];

        uint8_t mbr_type;

        uint8_t signature_type;

} _packed_;

#define device_path__contents                           \

        {                                               \

                uint8_t type;                           \

                uint8_t sub_type;                       \

                uint16_t length;                        \

                union {                                 \

                        uint16_t path[0];               \

                        struct drive_path drive;        \

                };                                      \

        }

struct device_path device_path__contents;

struct device_path__packed device_path__contents _packed_;

assert_cc(sizeof(struct device_path) == sizeof(struct device_path__packed));

#if ENABLE_EFI

static int get_os_indications(uint64_t *ret) {

        static struct stat cache_stat = {};

        _cleanup_free_ void *v = NULL;

        static uint64_t cache;

        struct stat new_stat;

        size_t s;

        int r;

        assert(ret);

        /* Let's verify general support first */

        r = efi_reboot_to_firmware_supported();

        if (r < 0)

                return r;

        /* stat() the EFI variable, to see if the mtime changed. If it did we need to cache again. */

        if (stat(EFIVAR_PATH(EFI_GLOBAL_VARIABLE_STR("OsIndications")), &new_stat) < 0) {

                if (errno != ENOENT)

                        return -errno;

                /* Doesn't exist? Then we can exit early (also see below) */

                *ret = 0;

                return 0;

        } else if (stat_inode_unmodified(&new_stat, &cache_stat)) {

                /* inode didn't change, we can return the cached value */

                *ret = cache;

                return 0;

        }

        r = efi_get_variable(EFI_GLOBAL_VARIABLE_STR("OsIndications"), NULL, &v, &s);

        if (r == -ENOENT) {

                /* Some firmware implementations that do support OsIndications and report that with

                 * OsIndicationsSupported will remove the OsIndications variable when it is unset. Let's

                 * pretend it's 0 then, to hide this implementation detail. Note that this call will return

                 * -ENOENT then only if the support for OsIndications is missing entirely, as determined by

                 * efi_reboot_to_firmware_supported() above. */

                *ret = 0;

                return 0;

        }

        if (r < 0)

                return r;

        if (s != sizeof(uint64_t))

                return -EINVAL;

        cache_stat = new_stat;

        *ret = cache = *(uint64_t *)v;

        return 0;

}

static ssize_t utf16_size(const uint16_t *s, size_t buf_len_bytes) {

        size_t l = 0;

        /* Returns the size of the string in bytes without the terminating two zero bytes */

        while (l < buf_len_bytes / sizeof(uint16_t)) {

                if (s[l] == 0)

                        return (l + 1) * sizeof(uint16_t);

                l++;

        }

        return -EINVAL; /* The terminator was not found */

}

static void to_utf16(uint16_t *dest, const char *src) {

        int i;

        for (i = 0; src[i] != '\0'; i++)

                dest[i] = src[i];

        dest[i] = '\0';

}

static uint16_t *tilt_slashes(uint16_t *s) {

        for (uint16_t *p = s; *p; p++)

                if (*p == '/')

                        *p = '\\';

        return s;

}

static int boot_id_hex(const char s[static 4]) {

        int id = 0;

        assert(s);

        for (int i = 0; i < 4; i++)

                if (s[i] >= '0' && s[i] <= '9')

                        id |= (s[i] - '0') << (3 - i) * 4;

                else if (s[i] >= 'A' && s[i] <= 'F')

                        id |= (s[i] - 'A' + 10) << (3 - i) * 4;

                else

                        return -EINVAL;

        return id;

}

#endif

int efi_reboot_to_firmware_supported(void) {

#if ENABLE_EFI

        _cleanup_free_ void *v = NULL;

        static int cache = -1;

        uint64_t b;

        size_t s;

        int r;

        if (cache > 0)

                return 0;

        if (cache == 0)

                return -EOPNOTSUPP;

        if (!is_efi_boot())

                goto not_supported;

        r = efi_get_variable(EFI_GLOBAL_VARIABLE_STR("OsIndicationsSupported"), NULL, &v, &s);

        if (r == -ENOENT)

                goto not_supported; /* variable doesn't exist? it's not supported then */

        if (r < 0)

                return r;

        if (s != sizeof(uint64_t))

                return -EINVAL;

        b = *(uint64_t*) v;

        if (!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI))

                goto not_supported; /* bit unset? it's not supported then */

        cache = 1;

        return 0;

not_supported:

        cache = 0;

        return -EOPNOTSUPP;

#else

        return -EOPNOTSUPP;

#endif

}

int efi_get_reboot_to_firmware(void) {

#if ENABLE_EFI

        int r;

        uint64_t b;

        r = get_os_indications(&b);

        if (r < 0)

                return r;

        return !!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI);

#else

        return -EOPNOTSUPP;

#endif

}

int efi_set_reboot_to_firmware(bool value) {

#if ENABLE_EFI

        int r;

        uint64_t b, b_new;

        r = get_os_indications(&b);

        if (r < 0)

                return r;

        b_new = UPDATE_FLAG(b, EFI_OS_INDICATIONS_BOOT_TO_FW_UI, value);

        /* Avoid writing to efi vars store if we can due to firmware bugs. */

        if (b != b_new)

                return efi_set_variable(EFI_GLOBAL_VARIABLE_STR("OsIndications"), &b_new, sizeof(uint64_t));

        return 0;

#else

        return -EOPNOTSUPP;

#endif

}

int efi_get_boot_option(

                uint16_t id,

                char **ret_title,

                sd_id128_t *ret_part_uuid,

                char **ret_path,

                bool *ret_active) {

#if ENABLE_EFI

        char variable[STRLEN(EFI_GLOBAL_VARIABLE_STR("Boot")) + 4 + 1];

        _cleanup_free_ uint8_t *buf = NULL;

        size_t l;

        struct boot_option *header;

        ssize_t title_size;

        _cleanup_free_ char *s = NULL, *p = NULL;

        sd_id128_t p_uuid = SD_ID128_NULL;

        int r;

        if (!is_efi_boot())

                return -EOPNOTSUPP;

        xsprintf(variable, EFI_GLOBAL_VARIABLE_STR("Boot%04X"), id);

        r = efi_get_variable(variable, NULL, (void **)&buf, &l);

        if (r < 0)

                return r;

        if (l < offsetof(struct boot_option, title))

                return -ENOENT;

        header = (struct boot_option *)buf;

        title_size = utf16_size(header->title, l - offsetof(struct boot_option, title));

        if (title_size < 0)

                return title_size;

        if (ret_title) {

                s = utf16_to_utf8(header->title, title_size);

                if (!s)

                        return -ENOMEM;

        }

        if (header->path_len > 0) {

                uint8_t *dbuf;

                size_t dnext, doff, path_len;

                doff = offsetof(struct boot_option, title) + title_size;

                dbuf = buf + doff;

                path_len = MIN((size_t) header->path_len, l - doff);

                dnext = 0;

                while (dnext < path_len) {

                        struct device_path *dpath;

                        size_t remaining = path_len - dnext;

                        if (remaining < offsetof(struct device_path, path))

                                break;

                        dpath = (struct device_path *)(dbuf + dnext);

                        if (dpath->length < offsetof(struct device_path, path) ||

                            dpath->length > remaining)

                                break;

                        /* Type 0x7F – End of Hardware Device Path, Sub-Type 0xFF – End Entire Device Path */

                        if (dpath->type == END_DEVICE_PATH_TYPE && dpath->sub_type == END_ENTIRE_DEVICE_PATH_SUBTYPE)

                                break;

                        dnext += dpath->length;

                        /* Type 0x04 – Media Device Path */

                        if (dpath->type != MEDIA_DEVICE_PATH)

                                continue;

                        /* Sub-Type 1 – Hard Drive */

                        if (dpath->sub_type == MEDIA_HARDDRIVE_DP) {

                                if (dpath->length < offsetof(struct device_path, drive) + sizeof(struct drive_path))

                                        break;

                                /* 0x02 – GUID Partition Table */

                                if (dpath->drive.mbr_type != MBR_TYPE_EFI_PARTITION_TABLE_HEADER)

                                        continue;

                                /* 0x02 – GUID signature */

                                if (dpath->drive.signature_type != SIGNATURE_TYPE_GUID)

                                        continue;

                                if (ret_part_uuid)

                                        p_uuid = efi_guid_to_id128(dpath->drive.signature);

                                continue;

                        }

                        /* Sub-Type 4 – File Path */

                        if (dpath->sub_type == MEDIA_FILEPATH_DP && !p && ret_path) {

                                p = utf16_to_utf8(dpath->path, dpath->length - offsetof(struct device_path, path));

                                if (!p)

                                        return -ENOMEM;

                                efi_tilt_backslashes(p);

                                continue;

                        }

                }

        }

        if (ret_title)

                *ret_title = TAKE_PTR(s);

        if (ret_part_uuid)

                *ret_part_uuid = p_uuid;

        if (ret_path)

                *ret_path = TAKE_PTR(p);

        if (ret_active)

                *ret_active = header->attr & LOAD_OPTION_ACTIVE;

        return 0;

#else

        return -EOPNOTSUPP;

#endif

}

int efi_add_boot_option(

                uint16_t id,

                const char *title,

                uint32_t part,

                uint64_t pstart,

                uint64_t psize,

                sd_id128_t part_uuid,

                const char *path) {

#if ENABLE_EFI

        size_t size, title_len, path_len;

        _cleanup_free_ char *buf = NULL;

        struct boot_option *option;

        struct device_path *devicep;

        char variable[STRLEN(EFI_GLOBAL_VARIABLE_STR("Boot")) + 4 + 1];

        if (!is_efi_boot())

                return -EOPNOTSUPP;

        title_len = (strlen(title)+1) * 2;

        path_len = (strlen(path)+1) * 2;

        buf = malloc0(offsetof(struct boot_option, title) + title_len +

                      sizeof(struct drive_path) +

                      sizeof(struct device_path) + path_len);

        if (!buf)

                return -ENOMEM;

        /* header */

        option = (struct boot_option *)buf;

        option->attr = LOAD_OPTION_ACTIVE;

        option->path_len = offsetof(struct device_path, drive) + sizeof(struct drive_path) +

                           offsetof(struct device_path, path) + path_len +

                           offsetof(struct device_path, path);

        to_utf16(option->title, title);

        size = offsetof(struct boot_option, title) + title_len;

        /* partition info */

        devicep = (struct device_path *)(buf + size);

        devicep->type = MEDIA_DEVICE_PATH;

        devicep->sub_type = MEDIA_HARDDRIVE_DP;

        devicep->length = offsetof(struct device_path, drive) + sizeof(struct drive_path);

        memcpy(&devicep->drive.part_nr, &part, sizeof(uint32_t));

        memcpy(&devicep->drive.part_start, &pstart, sizeof(uint64_t));

        memcpy(&devicep->drive.part_size, &psize, sizeof(uint64_t));

        efi_id128_to_guid(part_uuid, devicep->drive.signature);

        devicep->drive.mbr_type = MBR_TYPE_EFI_PARTITION_TABLE_HEADER;

        devicep->drive.signature_type = SIGNATURE_TYPE_GUID;

        size += devicep->length;

        /* path to loader */

        devicep = (struct device_path *)(buf + size);

        devicep->type = MEDIA_DEVICE_PATH;

        devicep->sub_type = MEDIA_FILEPATH_DP;

        devicep->length = offsetof(struct device_path, path) + path_len;

        to_utf16(devicep->path, path);

        tilt_slashes(devicep->path);

        size += devicep->length;

        /* end of path */

        devicep = (struct device_path *)(buf + size);

        devicep->type = END_DEVICE_PATH_TYPE;

        devicep->sub_type = END_ENTIRE_DEVICE_PATH_SUBTYPE;

        devicep->length = offsetof(struct device_path, path);

        size += devicep->length;

        xsprintf(variable, EFI_GLOBAL_VARIABLE_STR("Boot%04X"), id);

        return efi_set_variable(variable, buf, size);

#else

        return -EOPNOTSUPP;

#endif

}

int efi_remove_boot_option(uint16_t id) {

#if ENABLE_EFI

        char variable[STRLEN(EFI_GLOBAL_VARIABLE_STR("Boot")) + 4 + 1];

        if (!is_efi_boot())

                return -EOPNOTSUPP;

        xsprintf(variable, EFI_GLOBAL_VARIABLE_STR("Boot%04X"), id);

        return efi_set_variable(variable, NULL, 0);

#else

        return -EOPNOTSUPP;

#endif

}

int efi_get_boot_order(uint16_t **ret_order) {

#if ENABLE_EFI

        _cleanup_free_ void *buf = NULL;

        size_t l;

        int r;

        assert(ret_order);

        if (!is_efi_boot())

                return -EOPNOTSUPP;

        r = efi_get_variable(EFI_GLOBAL_VARIABLE_STR("BootOrder"), NULL, &buf, &l);

        if (r < 0)

                return r;

        if (l <= 0)

                return -ENOENT;

        if (l % sizeof(uint16_t) > 0 ||

            l / sizeof(uint16_t) > INT_MAX)

                return -EINVAL;

        *ret_order = TAKE_PTR(buf);

        return (int) (l / sizeof(uint16_t));

#else

        return -EOPNOTSUPP;

#endif

}

int efi_set_boot_order(const uint16_t *order, size_t n) {

#if ENABLE_EFI

        if (!is_efi_boot())

                return -EOPNOTSUPP;

        return efi_set_variable(EFI_GLOBAL_VARIABLE_STR("BootOrder"), order, n * sizeof(uint16_t));

#else

        return -EOPNOTSUPP;

#endif

}

int efi_get_boot_options(uint16_t **ret_options) {

#if ENABLE_EFI

        _cleanup_closedir_ DIR *dir = NULL;

        _cleanup_free_ uint16_t *list = NULL;

        int count = 0;

        assert(ret_options);

        if (!is_efi_boot())

                return -EOPNOTSUPP;

        dir = opendir(EFIVAR_PATH("."));

        if (!dir)

                return -errno;

        FOREACH_DIRENT(de, dir, return -errno) {

                int id;

                if (!startswith(de->d_name, "Boot"))

                        continue;

                if (strlen(de->d_name) != 45)

                        continue;

                if (!streq(de->d_name + 8, EFI_GLOBAL_VARIABLE_STR(""))) /* generate variable suffix using macro */

                        continue;

                id = boot_id_hex(de->d_name + 4);

                if (id < 0)

                        continue;

                if (!GREEDY_REALLOC(list, count + 1))

                        return -ENOMEM;

                list[count++] = id;

        }

        typesafe_qsort(list, count, cmp_uint16);

        *ret_options = TAKE_PTR(list);

        return count;

#else

        return -EOPNOTSUPP;

#endif

}

int efi_get_active_pcr_banks(uint32_t *ret) {

#if ENABLE_EFI

        static uint32_t cache = 0;

        static bool cache_valid = false;

        int r;

        /* Returns the enabled PCR banks as bitmask, as reported by firmware. If the bitmask is returned as

         * UINT32_MAX, the firmware supports the TCG protocol, but in a version too old to report this

         * information. */

        if (!cache_valid) {

                _cleanup_free_ char *active_pcr_banks = NULL;

                r = efi_get_variable_string(EFI_LOADER_VARIABLE_STR("LoaderTpm2ActivePcrBanks"), &active_pcr_banks);

                if (r < 0)

                        return log_debug_errno(r, "Failed to read LoaderTpm2ActivePcrBanks variable: %m");

                uint32_t efi_bits;

                r = safe_atou32_full(active_pcr_banks, 16, &efi_bits);

                if (r < 0)

                        return log_debug_errno(r, "Failed to parse LoaderTpm2ActivePcrBanks variable: %m");

                if (efi_bits == UINT32_MAX)

                        /* UINT32_MAX means that the firmware API doesn't implement GetActivePcrBanks() and caller must guess */

                        cache = UINT32_MAX;

                else {

                        /* EFI TPM protocol uses different bit values for the hash algorithms, let's convert */

                        static const struct {

                                uint32_t efi;

                                uint32_t tcg;

                        } table[] = {

                                { EFI_TCG2_BOOT_HASH_ALG_SHA1,   1U << TPM2_ALG_SHA1   },

                                { EFI_TCG2_BOOT_HASH_ALG_SHA256, 1U << TPM2_ALG_SHA256 },

                                { EFI_TCG2_BOOT_HASH_ALG_SHA384, 1U << TPM2_ALG_SHA384 },

                                { EFI_TCG2_BOOT_HASH_ALG_SHA512, 1U << TPM2_ALG_SHA512 },

                        };

                        uint32_t tcg_bits = 0;

                        FOREACH_ELEMENT(t, table)

                                SET_FLAG(tcg_bits, t->tcg, efi_bits & t->efi);

                        cache = tcg_bits;

                }

                cache_valid = true;

        }

        if (ret)

                *ret = cache;

        return 0;

#else

        return -EOPNOTSUPP;

#endif

}

#if ENABLE_EFI

static int loader_has_tpm2(void) {

        uint32_t active_pcr_banks;

        int r;

        r = efi_get_active_pcr_banks(&active_pcr_banks);

        if (r < 0)

                return r;

        return active_pcr_banks != 0;

}

#endif

bool efi_has_tpm2(void) {

#if ENABLE_EFI

        static int cache = -1;

        int r;

        /* Returns whether the system has a TPM2 chip which is known to the EFI firmware. */

        if (cache >= 0)

                return cache;

        /* First, check if we are on an EFI boot at all. */

        if (!is_efi_boot())

                return (cache = false);

        /* Secondly, check if the loader told us, as that is the most accurate source of information

         * regarding the firmware's setup */

        r = loader_has_tpm2();

        if (r >= 0)

                return (cache = r);

        /* Then, check if the ACPI table "TPM2" exists, which is the TPM2 event log table, see:

         * https://trustedcomputinggroup.org/wp-content/uploads/TCG_ACPIGeneralSpecification_v1.20_r8.pdf

         * This table exists whenever the firmware knows ACPI and is hooked up to TPM2.

         * Note that in some cases, for example with EDK2 2025.2 with the default arm64 config, this ACPI

         * table is present even if TPM2 support is not enabled in the firmware. */

        if (access("/sys/firmware/acpi/tables/TPM2", F_OK) >= 0)

                return (cache = true);

        if (errno != ENOENT)

                log_debug_errno(errno, "Unable to test whether /sys/firmware/acpi/tables/TPM2 exists, assuming it doesn't: %m");

        /* As the last try, check if the EFI firmware provides the EFI_TCG2_FINAL_EVENTS_TABLE

         * stored in EFI configuration table, see:

         *

         * https://trustedcomputinggroup.org/wp-content/uploads/EFI-Protocol-Specification-rev13-160330final.pdf */

        if (access("/sys/kernel/security/tpm0/binary_bios_measurements", F_OK) >= 0) {

                _cleanup_free_ char *major = NULL;

                /* The EFI table might exist for TPM 1.2 as well, hence let's check explicitly which TPM version we are looking at here. */

                r = read_virtual_file("/sys/class/tpm/tpm0/tpm_version_major", SIZE_MAX, &major, /* ret_size= */ NULL);

                if (r >= 0)

                        return (cache = streq(strstrip(major), "2"));

                log_debug_errno(r, "Unable to read /sys/class/tpm/tpm0/tpm_version_major, assuming TPM does not qualify as TPM2: %m");

        } else if (errno != ENOENT)

                  log_debug_errno(errno, "Unable to test whether /sys/kernel/security/tpm0/binary_bios_measurements exists, assuming it doesn't: %m");

        return (cache = false);

#else

        return -EOPNOTSUPP;

#endif

}

sd_id128_t efi_guid_to_id128(const void *guid) {

        EFI_GUID uuid;

        sd_id128_t id128;

        /* The input pointer is not guaranteed to be aligned (e.g. when pointing into a serialized EFI

         * variable buffer), so copy into a properly aligned local first. */

        memcpy(&uuid, ASSERT_PTR(guid), sizeof(uuid));

        id128.bytes[0] = (uuid.Data1 >> 24) & 0xff;

        id128.bytes[1] = (uuid.Data1 >> 16) & 0xff;

        id128.bytes[2] = (uuid.Data1 >> 8) & 0xff;

        id128.bytes[3] = uuid.Data1 & 0xff;

        id128.bytes[4] = (uuid.Data2 >> 8) & 0xff;

        id128.bytes[5] = uuid.Data2 & 0xff;

        id128.bytes[6] = (uuid.Data3 >> 8) & 0xff;

        id128.bytes[7] = uuid.Data3 & 0xff;

        memcpy(&id128.bytes[8], uuid.Data4, sizeof(uuid.Data4));

        return id128;

}

void efi_id128_to_guid(sd_id128_t id, void *ret_guid) {

        assert(ret_guid);

        EFI_GUID uuid = {

                .Data1 = (uint32_t) id.bytes[0] << 24 | (uint32_t) id.bytes[1] << 16 | (uint32_t) id.bytes[2] << 8 | id.bytes[3],

                .Data2 = (uint16_t) id.bytes[4] << 8 | id.bytes[5],

                .Data3 = (uint16_t) id.bytes[6] << 8 | id.bytes[7],

        };

        memcpy(uuid.Data4, id.bytes+8, sizeof(uuid.Data4));

        memcpy(ret_guid, &uuid, sizeof(uuid));

}