gpt-generator: relax EFI check a bit

Previously, we'd not mount the ESP except on EFI boots, and only when the ESP
used for booting matches the ESP we found.

With this change on non-EFI boots we'll mount a discovered ESP anyway, and on
EFI boots we'll only mount it if it matches the ESP we booted from.

1 files changed, 53 insertions, 54 deletions

diff --git a/src/gpt-auto-generator/gpt-auto-generator.c b/src/gpt-auto-generator/gpt-auto-generator.c
index dede86eabf..e4c913f2c4 100644
--- a/src/gpt-auto-generator/gpt-auto-generator.c
+++ b/src/gpt-auto-generator/gpt-auto-generator.c
@@ -450,19 +450,11 @@ static int add_automount(
 }
 
 static int add_boot(const char *what) {
-        _cleanup_blkid_free_probe_ blkid_probe b = NULL;
-        const char *fstype = NULL, *uuid = NULL;
-        sd_id128_t id, type_id;
         const char *esp;
         int r;
 
         assert(what);
 
-        if (!is_efi_boot()) {
-                log_debug("Not an EFI boot, ignoring the ESP.");
-                return 0;
-        }
-
         if (in_initrd()) {
                 log_debug("In initrd, ignoring the ESP.");
                 return 0;
@@ -487,58 +479,67 @@ static int add_boot(const char *what) {
                 return 0;
         }
 
-        r = efi_loader_get_device_part_uuid(&id);
-        if (r == -ENOENT) {
-                log_debug("EFI loader partition unknown.");
-                return 0;
-        }
-        if (r < 0) {
-                log_error_errno(r, "Failed to read ESP partition UUID: %m");
-                return r;
-        }
+        if (is_efi_boot()) {
+                _cleanup_blkid_free_probe_ blkid_probe b = NULL;
+                const char *fstype = NULL, *uuid_string = NULL;
+                sd_id128_t loader_uuid, part_uuid;
 
-        errno = 0;
-        b = blkid_new_probe_from_filename(what);
-        if (!b) {
-                if (errno == 0)
-                        return log_oom();
-                return log_error_errno(errno, "Failed to allocate prober: %m");
-        }
+                /* If this is an EFI boot, be extra careful, and only mount the ESP if it was the ESP used for booting. */
 
-        blkid_probe_enable_partitions(b, 1);
-        blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
+                r = efi_loader_get_device_part_uuid(&loader_uuid);
+                if (r == -ENOENT) {
+                        log_debug("EFI loader partition unknown.");
+                        return 0;
+                }
+                if (r < 0) {
+                        log_error_errno(r, "Failed to read ESP partition UUID: %m");
+                        return r;
+                }
 
-        errno = 0;
-        r = blkid_do_safeprobe(b);
-        if (r == -2 || r == 1) /* no result or uncertain */
-                return 0;
-        else if (r != 0)
-                return log_error_errno(errno ?: EIO, "Failed to probe %s: %m", what);
+                errno = 0;
+                b = blkid_new_probe_from_filename(what);
+                if (!b) {
+                        if (errno == 0)
+                                return log_oom();
+                        return log_error_errno(errno, "Failed to allocate prober: %m");
+                }
 
-        (void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
-        if (!streq_ptr(fstype, "vfat")) {
-                log_debug("Partition for %s is not a FAT filesystem, ignoring.", esp);
-                return 0;
-        }
+                blkid_probe_enable_partitions(b, 1);
+                blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
 
-        errno = 0;
-        r = blkid_probe_lookup_value(b, "PART_ENTRY_UUID", &uuid, NULL);
-        if (r != 0) {
-                log_debug_errno(errno, "Partition for %s does not have a UUID, ignoring.", esp);
-                return 0;
-        }
+                errno = 0;
+                r = blkid_do_safeprobe(b);
+                if (r == -2 || r == 1) /* no result or uncertain */
+                        return 0;
+                else if (r != 0)
+                        return log_error_errno(errno ?: EIO, "Failed to probe %s: %m", what);
 
-        if (sd_id128_from_string(uuid, &type_id) < 0) {
-                log_debug("Partition for %s does not have a valid UUID, ignoring.", esp);
-                return 0;
-        }
+                (void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
+                if (!streq_ptr(fstype, "vfat")) {
+                        log_debug("Partition for %s is not a FAT filesystem, ignoring.", esp);
+                        return 0;
+                }
 
-        if (!sd_id128_equal(type_id, id)) {
-                log_debug("Partition for %s does not appear to be the partition we are booted from.", esp);
-                return 0;
-        }
+                errno = 0;
+                r = blkid_probe_lookup_value(b, "PART_ENTRY_UUID", &uuid_string, NULL);
+                if (r != 0) {
+                        log_debug_errno(errno, "Partition for %s does not have a UUID, ignoring.", esp);
+                        return 0;
+                }
 
-        r = add_automount("boot",
+                if (sd_id128_from_string(uuid_string, &part_uuid) < 0) {
+                        log_debug("Partition for %s does not have a valid UUID, ignoring.", esp);
+                        return 0;
+                }
+
+                if (!sd_id128_equal(part_uuid, loader_uuid)) {
+                        log_debug("Partition for %s does not appear to be the partition we are booted from.", esp);
+                        return 0;
+                }
+        } else
+                log_debug("Not an EFI boot, skipping ESP check.");
+
+        return add_automount("boot",
                           what,
                           esp,
                           "vfat",
@@ -546,8 +547,6 @@ static int add_boot(const char *what) {
                           "umask=0077",
                           "EFI System Partition Automount",
                           120 * USEC_PER_SEC);
-
-        return r;
 }
 #else
 static int add_boot(const char *what) {