/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include "alloc-util.h" #include "dirent-util.h" #include "efi-api.h" #include "efi-fundamental.h" #include "efivars.h" #include "fd-util.h" #include "fileio.h" #include "sort-util.h" #include "stat-util.h" #include "stdio-util.h" #include "utf8.h" #if ENABLE_EFI #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)); int efi_reboot_to_firmware_supported(void) { _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(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; } 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(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(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; } int efi_get_reboot_to_firmware(void) { int r; uint64_t b; r = get_os_indications(&b); if (r < 0) return r; return !!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI); } int efi_set_reboot_to_firmware(bool value) { 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(OsIndications), &b_new, sizeof(uint64_t)); 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 */ } int efi_get_boot_option( uint16_t id, char **ret_title, sd_id128_t *ret_part_uuid, char **ret_path, bool *ret_active) { 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; doff = offsetof(struct boot_option, title) + title_size; dbuf = buf + doff; if (header->path_len > l - doff) return -EINVAL; dnext = 0; while (dnext < header->path_len) { struct device_path *dpath; dpath = (struct device_path *)(dbuf + dnext); if (dpath->length < 4) 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) { /* 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-4); 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; } 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; } 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) { 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); } int efi_remove_boot_option(uint16_t id) { 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); } int efi_get_boot_order(uint16_t **ret_order) { _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(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)); } int efi_set_boot_order(const uint16_t *order, size_t n) { if (!is_efi_boot()) return -EOPNOTSUPP; return efi_set_variable(EFI_GLOBAL_VARIABLE(BootOrder), order, n * sizeof(uint16_t)); } 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; } int efi_get_boot_options(uint16_t **ret_options) { _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; } bool efi_has_tpm2(void) { 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); /* 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. */ 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); } #endif sd_id128_t efi_guid_to_id128(const void *guid) { const EFI_GUID *uuid = ASSERT_PTR(guid); /* cast is safe, because struct efi_guid is packed */ sd_id128_t id128; 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 = id.bytes[0] << 24 | id.bytes[1] << 16 | id.bytes[2] << 8 | id.bytes[3], .Data2 = id.bytes[4] << 8 | id.bytes[5], .Data3 = id.bytes[6] << 8 | id.bytes[7], }; memcpy(uuid.Data4, id.bytes+8, sizeof(uuid.Data4)); memcpy(ret_guid, &uuid, sizeof(uuid)); }