diff options
Diffstat (limited to 'src/libsystemd-shared/src/efivars.c')
| -rw-r--r-- | src/libsystemd-shared/src/efivars.c | 715 |
1 files changed, 715 insertions, 0 deletions
diff --git a/src/libsystemd-shared/src/efivars.c b/src/libsystemd-shared/src/efivars.c new file mode 100644 index 0000000000..5bc5870ebf --- /dev/null +++ b/src/libsystemd-shared/src/efivars.c @@ -0,0 +1,715 @@ +/*** + This file is part of systemd. + + Copyright 2013 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <dirent.h> +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/stat.h> +#include <unistd.h> + +#include <systemd/sd-id128.h> + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/dirent-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/io-util.h" +#include "systemd-basic/macro.h" +#include "systemd-basic/parse-util.h" +#include "systemd-basic/stdio-util.h" +#include "systemd-basic/time-util.h" +#include "systemd-basic/utf8.h" +#include "systemd-basic/util.h" +#include "systemd-basic/virt.h" +#include "systemd-shared/efivars.h" + +#ifdef 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 0x0000000000000001 + +struct boot_option { + uint32_t attr; + uint16_t path_len; + uint16_t title[]; +} _packed_; + +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_; + +struct device_path { + uint8_t type; + uint8_t sub_type; + uint16_t length; + union { + uint16_t path[0]; + struct drive_path drive; + }; +} _packed_; + +bool is_efi_boot(void) { + return access("/sys/firmware/efi", F_OK) >= 0; +} + +static int read_flag(const char *varname) { + int r; + _cleanup_free_ void *v = NULL; + size_t s; + uint8_t b; + + r = efi_get_variable(EFI_VENDOR_GLOBAL, varname, NULL, &v, &s); + if (r < 0) + return r; + + if (s != 1) + return -EINVAL; + + b = *(uint8_t *)v; + r = b > 0; + return r; +} + +bool is_efi_secure_boot(void) { + return read_flag("SecureBoot") > 0; +} + +bool is_efi_secure_boot_setup_mode(void) { + return read_flag("SetupMode") > 0; +} + +int efi_reboot_to_firmware_supported(void) { + int r; + size_t s; + uint64_t b; + _cleanup_free_ void *v = NULL; + + if (!is_efi_boot() || detect_container() > 0) + return -EOPNOTSUPP; + + r = efi_get_variable(EFI_VENDOR_GLOBAL, "OsIndicationsSupported", NULL, &v, &s); + if (r < 0) + return r; + else if (s != sizeof(uint64_t)) + return -EINVAL; + + b = *(uint64_t *)v; + b &= EFI_OS_INDICATIONS_BOOT_TO_FW_UI; + return b > 0 ? 0 : -EOPNOTSUPP; +} + +static int get_os_indications(uint64_t *os_indication) { + int r; + size_t s; + _cleanup_free_ void *v = NULL; + + r = efi_reboot_to_firmware_supported(); + if (r < 0) + return r; + + r = efi_get_variable(EFI_VENDOR_GLOBAL, "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. */ + *os_indication = 0; + return 0; + } else if (r < 0) + return r; + else if (s != sizeof(uint64_t)) + return -EINVAL; + + *os_indication = *(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; + + if (value) + b_new = b | EFI_OS_INDICATIONS_BOOT_TO_FW_UI; + else + b_new = b & ~EFI_OS_INDICATIONS_BOOT_TO_FW_UI; + + /* Avoid writing to efi vars store if we can due to firmware bugs. */ + if (b != b_new) + return efi_set_variable(EFI_VENDOR_GLOBAL, "OsIndications", &b_new, sizeof(uint64_t)); + + return 0; +} + +int efi_get_variable( + sd_id128_t vendor, + const char *name, + uint32_t *attribute, + void **value, + size_t *size) { + + _cleanup_close_ int fd = -1; + _cleanup_free_ char *p = NULL; + uint32_t a; + ssize_t n; + struct stat st; + _cleanup_free_ void *buf = NULL; + + assert(name); + assert(value); + assert(size); + + if (asprintf(&p, + "/sys/firmware/efi/efivars/%s-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", + name, SD_ID128_FORMAT_VAL(vendor)) < 0) + return -ENOMEM; + + fd = open(p, O_RDONLY|O_NOCTTY|O_CLOEXEC); + if (fd < 0) + return -errno; + + if (fstat(fd, &st) < 0) + return -errno; + if (st.st_size < 4) + return -EIO; + if (st.st_size > 4*1024*1024 + 4) + return -E2BIG; + + n = read(fd, &a, sizeof(a)); + if (n < 0) + return -errno; + if (n != sizeof(a)) + return -EIO; + + buf = malloc(st.st_size - 4 + 2); + if (!buf) + return -ENOMEM; + + n = read(fd, buf, (size_t) st.st_size - 4); + if (n < 0) + return -errno; + if (n != (ssize_t) st.st_size - 4) + return -EIO; + + /* Always NUL terminate (2 bytes, to protect UTF-16) */ + ((char*) buf)[st.st_size - 4] = 0; + ((char*) buf)[st.st_size - 4 + 1] = 0; + + *value = buf; + buf = NULL; + *size = (size_t) st.st_size - 4; + + if (attribute) + *attribute = a; + + return 0; +} + +int efi_set_variable( + sd_id128_t vendor, + const char *name, + const void *value, + size_t size) { + + struct var { + uint32_t attr; + char buf[]; + } _packed_ * _cleanup_free_ buf = NULL; + _cleanup_free_ char *p = NULL; + _cleanup_close_ int fd = -1; + + assert(name); + + if (asprintf(&p, + "/sys/firmware/efi/efivars/%s-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", + name, SD_ID128_FORMAT_VAL(vendor)) < 0) + return -ENOMEM; + + if (size == 0) { + if (unlink(p) < 0) + return -errno; + return 0; + } + + fd = open(p, O_WRONLY|O_CREAT|O_NOCTTY|O_CLOEXEC, 0644); + if (fd < 0) + return -errno; + + buf = malloc(sizeof(uint32_t) + size); + if (!buf) + return -ENOMEM; + + buf->attr = EFI_VARIABLE_NON_VOLATILE|EFI_VARIABLE_BOOTSERVICE_ACCESS|EFI_VARIABLE_RUNTIME_ACCESS; + memcpy(buf->buf, value, size); + + return loop_write(fd, buf, sizeof(uint32_t) + size, false); +} + +int efi_get_variable_string(sd_id128_t vendor, const char *name, char **p) { + _cleanup_free_ void *s = NULL; + size_t ss = 0; + int r; + char *x; + + r = efi_get_variable(vendor, name, NULL, &s, &ss); + if (r < 0) + return r; + + x = utf16_to_utf8(s, ss); + if (!x) + return -ENOMEM; + + *p = x; + return 0; +} + +static size_t utf16_size(const uint16_t *s) { + size_t l = 0; + + while (s[l] > 0) + l++; + + return (l+1) * sizeof(uint16_t); +} + +static void efi_guid_to_id128(const void *guid, sd_id128_t *id128) { + struct uuid { + uint32_t u1; + uint16_t u2; + uint16_t u3; + uint8_t u4[8]; + } _packed_; + const struct uuid *uuid = guid; + + id128->bytes[0] = (uuid->u1 >> 24) & 0xff; + id128->bytes[1] = (uuid->u1 >> 16) & 0xff; + id128->bytes[2] = (uuid->u1 >> 8) & 0xff; + id128->bytes[3] = (uuid->u1) & 0xff; + id128->bytes[4] = (uuid->u2 >> 8) & 0xff; + id128->bytes[5] = (uuid->u2) & 0xff; + id128->bytes[6] = (uuid->u3 >> 8) & 0xff; + id128->bytes[7] = (uuid->u3) & 0xff; + memcpy(&id128->bytes[8], uuid->u4, sizeof(uuid->u4)); +} + +int efi_get_boot_option( + uint16_t id, + char **title, + sd_id128_t *part_uuid, + char **path, + bool *active) { + + char boot_id[9]; + _cleanup_free_ uint8_t *buf = NULL; + size_t l; + struct boot_option *header; + size_t title_size; + _cleanup_free_ char *s = NULL, *p = NULL; + sd_id128_t p_uuid = SD_ID128_NULL; + int r; + + xsprintf(boot_id, "Boot%04X", id); + r = efi_get_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, (void **)&buf, &l); + if (r < 0) + return r; + if (l < sizeof(struct boot_option)) + return -ENOENT; + + header = (struct boot_option *)buf; + title_size = utf16_size(header->title); + if (title_size > l - offsetof(struct boot_option, title)) + return -EINVAL; + + if (title) { + s = utf16_to_utf8(header->title, title_size); + if (!s) + return -ENOMEM; + } + + if (header->path_len > 0) { + uint8_t *dbuf; + size_t dnext; + + dbuf = buf + offsetof(struct boot_option, title) + title_size; + 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 (part_uuid) + efi_guid_to_id128(dpath->drive.signature, &p_uuid); + continue; + } + + /* Sub-Type 4 – File Path */ + if (dpath->sub_type == MEDIA_FILEPATH_DP && !p && path) { + p = utf16_to_utf8(dpath->path, dpath->length-4); + efi_tilt_backslashes(p); + continue; + } + } + } + + if (title) { + *title = s; + s = NULL; + } + if (part_uuid) + *part_uuid = p_uuid; + if (path) { + *path = p; + p = NULL; + } + if (active) + *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'; +} + +struct guid { + uint32_t u1; + uint16_t u2; + uint16_t u3; + uint8_t u4[8]; +} _packed_; + +static void id128_to_efi_guid(sd_id128_t id, void *guid) { + struct guid *uuid = guid; + + uuid->u1 = id.bytes[0] << 24 | id.bytes[1] << 16 | id.bytes[2] << 8 | id.bytes[3]; + uuid->u2 = id.bytes[4] << 8 | id.bytes[5]; + uuid->u3 = id.bytes[6] << 8 | id.bytes[7]; + memcpy(uuid->u4, id.bytes+8, sizeof(uuid->u4)); +} + +static uint16_t *tilt_slashes(uint16_t *s) { + uint16_t *p; + + for (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) { + char boot_id[9]; + size_t size; + size_t title_len; + size_t path_len; + struct boot_option *option; + struct device_path *devicep; + _cleanup_free_ char *buf = NULL; + + title_len = (strlen(title)+1) * 2; + path_len = (strlen(path)+1) * 2; + + buf = calloc(sizeof(struct boot_option) + title_len + + sizeof(struct drive_path) + + sizeof(struct device_path) + path_len, 1); + 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); + devicep->drive.part_nr = part; + devicep->drive.part_start = pstart; + devicep->drive.part_size = psize; + devicep->drive.signature_type = SIGNATURE_TYPE_GUID; + devicep->drive.mbr_type = MBR_TYPE_EFI_PARTITION_TABLE_HEADER; + id128_to_efi_guid(part_uuid, devicep->drive.signature); + 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(boot_id, "Boot%04X", id); + return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, buf, size); +} + +int efi_remove_boot_option(uint16_t id) { + char boot_id[9]; + + xsprintf(boot_id, "Boot%04X", id); + return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, 0); +} + +int efi_get_boot_order(uint16_t **order) { + _cleanup_free_ void *buf = NULL; + size_t l; + int r; + + r = efi_get_variable(EFI_VENDOR_GLOBAL, "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; + + *order = buf; + buf = NULL; + return (int) (l / sizeof(uint16_t)); +} + +int efi_set_boot_order(uint16_t *order, size_t n) { + return efi_set_variable(EFI_VENDOR_GLOBAL, "BootOrder", order, n * sizeof(uint16_t)); +} + +static int boot_id_hex(const char s[4]) { + int i; + int id = 0; + + for (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; +} + +static int cmp_uint16(const void *_a, const void *_b) { + const uint16_t *a = _a, *b = _b; + + return (int)*a - (int)*b; +} + +int efi_get_boot_options(uint16_t **options) { + _cleanup_closedir_ DIR *dir = NULL; + struct dirent *de; + _cleanup_free_ uint16_t *list = NULL; + size_t alloc = 0; + int count = 0; + + assert(options); + + dir = opendir("/sys/firmware/efi/efivars/"); + if (!dir) + return -errno; + + FOREACH_DIRENT(de, dir, return -errno) { + int id; + + if (strncmp(de->d_name, "Boot", 4) != 0) + continue; + + if (strlen(de->d_name) != 45) + continue; + + if (strcmp(de->d_name + 8, "-8be4df61-93ca-11d2-aa0d-00e098032b8c") != 0) + continue; + + id = boot_id_hex(de->d_name + 4); + if (id < 0) + continue; + + if (!GREEDY_REALLOC(list, alloc, count + 1)) + return -ENOMEM; + + list[count++] = id; + } + + qsort_safe(list, count, sizeof(uint16_t), cmp_uint16); + + *options = list; + list = NULL; + return count; +} + +static int read_usec(sd_id128_t vendor, const char *name, usec_t *u) { + _cleanup_free_ char *j = NULL; + int r; + uint64_t x = 0; + + assert(name); + assert(u); + + r = efi_get_variable_string(EFI_VENDOR_LOADER, name, &j); + if (r < 0) + return r; + + r = safe_atou64(j, &x); + if (r < 0) + return r; + + *u = x; + return 0; +} + +int efi_loader_get_boot_usec(usec_t *firmware, usec_t *loader) { + uint64_t x, y; + int r; + + assert(firmware); + assert(loader); + + r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeInitUSec", &x); + if (r < 0) + return r; + + r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeExecUSec", &y); + if (r < 0) + return r; + + if (y == 0 || y < x) + return -EIO; + + if (y > USEC_PER_HOUR) + return -EIO; + + *firmware = x; + *loader = y; + + return 0; +} + +int efi_loader_get_device_part_uuid(sd_id128_t *u) { + _cleanup_free_ char *p = NULL; + int r, parsed[16]; + + r = efi_get_variable_string(EFI_VENDOR_LOADER, "LoaderDevicePartUUID", &p); + if (r < 0) + return r; + + if (sscanf(p, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", + &parsed[0], &parsed[1], &parsed[2], &parsed[3], + &parsed[4], &parsed[5], &parsed[6], &parsed[7], + &parsed[8], &parsed[9], &parsed[10], &parsed[11], + &parsed[12], &parsed[13], &parsed[14], &parsed[15]) != 16) + return -EIO; + + if (u) { + unsigned i; + + for (i = 0; i < ELEMENTSOF(parsed); i++) + u->bytes[i] = parsed[i]; + } + + return 0; +} + +#endif + +char *efi_tilt_backslashes(char *s) { + char *p; + + for (p = s; *p; p++) + if (*p == '\\') + *p = '/'; + + return s; +} |