summaryrefslogtreecommitdiff
path: root/src/libshared/efivars.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/libshared/efivars.c')
-rw-r--r--src/libshared/efivars.c715
1 files changed, 715 insertions, 0 deletions
diff --git a/src/libshared/efivars.c b/src/libshared/efivars.c
new file mode 100644
index 0000000000..5073c61740
--- /dev/null
+++ b/src/libshared/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 "alloc-util.h"
+#include "dirent-util.h"
+#include "efivars.h"
+#include "fd-util.h"
+#include "io-util.h"
+#include "macro.h"
+#include "parse-util.h"
+#include "stdio-util.h"
+#include "time-util.h"
+#include "utf8.h"
+#include "util.h"
+#include "virt.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;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-05 06:48:08 +0000