Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 363 insertions, 0 deletions

diff --git a/src/shared/efi-loader.c b/src/shared/efi-loader.c
new file mode 100644
index 0000000..7d6bda9
--- /dev/null
+++ b/src/shared/efi-loader.c
@@ -0,0 +1,363 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "efi-api.h"
+#include "efi-loader.h"
+#include "env-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "stat-util.h"
+#include "strv.h"
+#include "tpm2-pcr.h"
+#include "utf8.h"
+
+#if ENABLE_EFI
+
+static int read_usec(const char *variable, usec_t *ret) {
+        _cleanup_free_ char *j = NULL;
+        uint64_t x = 0;
+        int r;
+
+        assert(variable);
+        assert(ret);
+
+        r = efi_get_variable_string(variable, &j);
+        if (r < 0)
+                return r;
+
+        r = safe_atou64(j, &x);
+        if (r < 0)
+                return r;
+
+        *ret = x;
+        return 0;
+}
+
+int efi_loader_get_boot_usec(usec_t *ret_firmware, usec_t *ret_loader) {
+        uint64_t x, y;
+        int r;
+
+        assert(ret_firmware);
+        assert(ret_loader);
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = read_usec(EFI_LOADER_VARIABLE(LoaderTimeInitUSec), &x);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to read LoaderTimeInitUSec: %m");
+
+        r = read_usec(EFI_LOADER_VARIABLE(LoaderTimeExecUSec), &y);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to read LoaderTimeExecUSec: %m");
+
+        if (y == 0 || y < x || y - x > USEC_PER_HOUR)
+                return log_debug_errno(SYNTHETIC_ERRNO(EIO),
+                                       "Bad LoaderTimeInitUSec=%"PRIu64", LoaderTimeExecUSec=%" PRIu64"; refusing.",
+                                       x, y);
+
+        *ret_firmware = x;
+        *ret_loader = y;
+        return 0;
+}
+
+int efi_loader_get_device_part_uuid(sd_id128_t *ret) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+        unsigned parsed[16];
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderDevicePartUUID), &p);
+        if (r < 0)
+                return r;
+
+        if (sscanf(p, SD_ID128_UUID_FORMAT_STR,
+                   &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 (ret)
+                for (unsigned i = 0; i < ELEMENTSOF(parsed); i++)
+                        ret->bytes[i] = parsed[i];
+
+        return 0;
+}
+
+int efi_loader_get_entries(char ***ret) {
+        _cleanup_free_ char16_t *entries = NULL;
+        _cleanup_strv_free_ char **l = NULL;
+        size_t size;
+        int r;
+
+        assert(ret);
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = efi_get_variable(EFI_LOADER_VARIABLE(LoaderEntries), NULL, (void**) &entries, &size);
+        if (r < 0)
+                return r;
+
+        /* The variable contains a series of individually NUL terminated UTF-16 strings. We gracefully
+         * consider the final NUL byte optional (i.e. the last string may or may not end in a NUL byte).*/
+
+        for (size_t i = 0, start = 0;; i++) {
+                _cleanup_free_ char *decoded = NULL;
+                bool end;
+
+                /* Is this the end of the variable's data? */
+                end = i * sizeof(char16_t) >= size;
+
+                /* Are we in the middle of a string? (i.e. not at the end of the variable, nor at a NUL terminator?) If
+                 * so, let's go to the next entry. */
+                if (!end && entries[i] != 0)
+                        continue;
+
+                /* Empty string at the end of variable? That's the trailer, we are done (i.e. we have a final
+                 * NUL terminator). */
+                if (end && start == i)
+                        break;
+
+                /* We reached the end of a string, let's decode it into UTF-8 */
+                decoded = utf16_to_utf8(entries + start, (i - start) * sizeof(char16_t));
+                if (!decoded)
+                        return -ENOMEM;
+
+                if (efi_loader_entry_name_valid(decoded)) {
+                        r = strv_consume(&l, TAKE_PTR(decoded));
+                        if (r < 0)
+                                return r;
+                } else
+                        log_debug("Ignoring invalid loader entry '%s'.", decoded);
+
+                /* Exit the loop if we reached the end of the variable (i.e. we do not have a final NUL
+                 * terminator) */
+                if (end)
+                        break;
+
+                /* Continue after the NUL byte */
+                start = i + 1;
+        }
+
+        *ret = TAKE_PTR(l);
+        return 0;
+}
+
+int efi_loader_get_features(uint64_t *ret) {
+        _cleanup_free_ void *v = NULL;
+        size_t s;
+        int r;
+
+        assert(ret);
+
+        if (!is_efi_boot()) {
+                *ret = 0;
+                return 0;
+        }
+
+        r = efi_get_variable(EFI_LOADER_VARIABLE(LoaderFeatures), NULL, &v, &s);
+        if (r == -ENOENT) {
+                _cleanup_free_ char *info = NULL;
+
+                /* The new (v240+) LoaderFeatures variable is not supported, let's see if it's systemd-boot at all */
+                r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderInfo), &info);
+                if (r < 0) {
+                        if (r != -ENOENT)
+                                return r;
+
+                        /* Variable not set, definitely means not systemd-boot */
+
+                } else if (first_word(info, "systemd-boot")) {
+
+                        /* An older systemd-boot version. Let's hardcode the feature set, since it was pretty
+                         * static in all its versions. */
+
+                        *ret = EFI_LOADER_FEATURE_CONFIG_TIMEOUT |
+                                EFI_LOADER_FEATURE_ENTRY_DEFAULT |
+                                EFI_LOADER_FEATURE_ENTRY_ONESHOT;
+
+                        return 0;
+                }
+
+                /* No features supported */
+                *ret = 0;
+                return 0;
+        }
+        if (r < 0)
+                return r;
+
+        if (s != sizeof(uint64_t))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "LoaderFeatures EFI variable doesn't have the right size.");
+
+        memcpy(ret, v, sizeof(uint64_t));
+        return 0;
+}
+
+int efi_stub_get_features(uint64_t *ret) {
+        _cleanup_free_ void *v = NULL;
+        size_t s;
+        int r;
+
+        assert(ret);
+
+        if (!is_efi_boot()) {
+                *ret = 0;
+                return 0;
+        }
+
+        r = efi_get_variable(EFI_LOADER_VARIABLE(StubFeatures), NULL, &v, &s);
+        if (r == -ENOENT) {
+                _cleanup_free_ char *info = NULL;
+
+                /* The new (v252+) StubFeatures variable is not supported, let's see if it's systemd-stub at all */
+                r = efi_get_variable_string(EFI_LOADER_VARIABLE(StubInfo), &info);
+                if (r < 0) {
+                        if (r != -ENOENT)
+                                return r;
+
+                        /* Variable not set, definitely means not systemd-stub */
+
+                } else if (first_word(info, "systemd-stub")) {
+
+                        /* An older systemd-stub version. Let's hardcode the feature set, since it was pretty
+                         * static in all its versions. */
+
+                        *ret = EFI_STUB_FEATURE_REPORT_BOOT_PARTITION;
+                        return 0;
+                }
+
+                /* No features supported */
+                *ret = 0;
+                return 0;
+        }
+        if (r < 0)
+                return r;
+
+        if (s != sizeof(uint64_t))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "StubFeatures EFI variable doesn't have the right size.");
+
+        memcpy(ret, v, sizeof(uint64_t));
+        return 0;
+}
+
+int efi_measured_uki(int log_level) {
+        _cleanup_free_ char *pcr_string = NULL;
+        static int cached = -1;
+        unsigned pcr_nr;
+        int r;
+
+        if (cached >= 0)
+                return cached;
+
+        /* Checks if we are booted on a kernel with sd-stub which measured the kernel into PCR 11 on a TPM2
+         * chip. Or in other words, if we are running on a TPM enabled UKI. (TPM 1.2 situations are ignored.)
+         *
+         * Returns == 0 and > 0 depending on the result of the test. Returns -EREMOTE if we detected a stub
+         * being used, but it measured things into a different PCR than we are configured for in
+         * userspace. (i.e. we expect PCR 11 being used for this by both sd-stub and us) */
+
+        r = getenv_bool_secure("SYSTEMD_FORCE_MEASURE"); /* Give user a chance to override the variable test,
+                                                          * for debugging purposes */
+        if (r >= 0)
+                return (cached = r);
+        if (r != -ENXIO)
+                log_debug_errno(r, "Failed to parse $SYSTEMD_FORCE_MEASURE, ignoring: %m");
+
+        if (!efi_has_tpm2())
+                return (cached = 0);
+
+        r = efi_get_variable_string(EFI_LOADER_VARIABLE(StubPcrKernelImage), &pcr_string);
+        if (r == -ENOENT)
+                return (cached = 0);
+        if (r < 0)
+                return log_full_errno(log_level, r,
+                                      "Failed to get StubPcrKernelImage EFI variable: %m");
+
+        r = safe_atou(pcr_string, &pcr_nr);
+        if (r < 0)
+                return log_full_errno(log_level, r,
+                                      "Failed to parse StubPcrKernelImage EFI variable: %s", pcr_string);
+        if (pcr_nr != TPM2_PCR_KERNEL_BOOT)
+                return log_full_errno(log_level, SYNTHETIC_ERRNO(EREMOTE),
+                                      "Kernel stub measured kernel image into PCR %u, which is different than expected %i.",
+                                      pcr_nr, TPM2_PCR_KERNEL_BOOT);
+
+        return (cached = 1);
+}
+
+int efi_loader_get_config_timeout_one_shot(usec_t *ret) {
+        _cleanup_free_ char *v = NULL;
+        static struct stat cache_stat = {};
+        struct stat new_stat;
+        static usec_t cache;
+        uint64_t sec;
+        int r;
+
+        assert(ret);
+
+        /* stat() the EFI variable, to see if the mtime changed. If it did, we need to cache again. */
+        if (stat(EFIVAR_PATH(EFI_LOADER_VARIABLE(LoaderConfigTimeoutOneShot)), &new_stat) < 0)
+                return -errno;
+
+        if (stat_inode_unmodified(&new_stat, &cache_stat)) {
+                *ret = cache;
+                return 0;
+        }
+
+        r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderConfigTimeoutOneShot), &v);
+        if (r < 0)
+                return r;
+
+        r = safe_atou64(v, &sec);
+        if (r < 0)
+                return r;
+        if (sec > USEC_INFINITY / USEC_PER_SEC)
+                return -ERANGE;
+
+        cache_stat = new_stat;
+        *ret = cache = sec * USEC_PER_SEC; /* return in μs */
+        return 0;
+}
+
+int efi_loader_update_entry_one_shot_cache(char **cache, struct stat *cache_stat) {
+        _cleanup_free_ char *v = NULL;
+        struct stat new_stat;
+        int r;
+
+        assert(cache);
+        assert(cache_stat);
+
+        /* stat() the EFI variable, to see if the mtime changed. If it did we need to cache again. */
+        if (stat(EFIVAR_PATH(EFI_LOADER_VARIABLE(LoaderEntryOneShot)), &new_stat) < 0)
+                return -errno;
+
+        if (stat_inode_unmodified(&new_stat, cache_stat))
+                return 0;
+
+        r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderEntryOneShot), &v);
+        if (r < 0)
+                return r;
+
+        if (!efi_loader_entry_name_valid(v))
+                return -EINVAL;
+
+        *cache_stat = new_stat;
+        free_and_replace(*cache, v);
+
+        return 0;
+}
+
+#endif
+
+bool efi_loader_entry_name_valid(const char *s) {
+        if (!filename_is_valid(s)) /* Make sure entry names fit in filenames */
+                return false;
+
+        return in_charset(s, ALPHANUMERICAL "+-_.");
+}