[PATCH v2 3/3] grub-core/kern/disk.c: handle LUKS2 devices

[Pierre-Louis Bonicoli]

Unlike LUKS1, the sector size of LUKS2 devices isn't hardcoded.

Regarding the probe command, the following values of --target switch
are affected: abstraction, arc_hints, baremetal_hints, bios_hints,
cryptodisk_uuid, drive, efi_hints, hints_string, ieee1275_hints,
zero_check.

For example using the --target=drive option:

  # dd if=/dev/zero of=data count=10 bs=1M
  # losetup --show -f data
  /dev/loop4
  # echo -n pass | cryptsetup luksFormat -v --type luks2 /dev/loop4
  Key slot 0 created.
  Command successful.
  # echo -n pass | cryptsetup -v open /dev/loop4 test
  No usable token is available.
  Key slot 0 unlocked.
  Command successful.
  # grub-probe --device /dev/mapper/test --target=cryptodisk_uuid
  grub-probe: error: disk `cryptouuid/f353c0f04a6a4c08bc53a0896130910f' not 
found.

The updated output:

  # grub-probe --device /dev/mapper/test --target=cryptodisk_uuid
  f353c0f04a6a4c08bc53a0896130910f
---
 grub-core/kern/disk.c               | 4 +++-
 grub-core/osdep/devmapper/getroot.c | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/grub-core/kern/disk.c b/grub-core/kern/disk.c
index 3a42c007b..fa3177bf0 100644
--- a/grub-core/kern/disk.c
+++ b/grub-core/kern/disk.c
@@ -237,8 +237,10 @@ grub_disk_open (const char *name)
                  name);
       goto fail;
     }
-  if (disk->log_sector_size > GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS
+  if ((disk->log_sector_size > GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS
       || disk->log_sector_size < GRUB_DISK_SECTOR_BITS)
+      /* log_sector_size is unset for LUKS2 and that's ok */
+      && !(disk->log_sector_size == 0 && dev->id == 
GRUB_DISK_DEVICE_CRYPTODISK_ID))
     {
       grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
                  "sector sizes of %d bytes aren't supported yet",
diff --git a/grub-core/osdep/devmapper/getroot.c 
b/grub-core/osdep/devmapper/getroot.c
index 96781714c..4f51c113c 100644
--- a/grub-core/osdep/devmapper/getroot.c
+++ b/grub-core/osdep/devmapper/getroot.c
@@ -180,7 +180,8 @@ grub_util_pull_devmapper (const char *os_dev)
          grub_util_pull_device (subdev);
        }
     }
-  if (uuid && strncmp (uuid, "CRYPT-LUKS1-", sizeof ("CRYPT-LUKS1-") - 1) == 0
+  if (uuid && (strncmp (uuid, "CRYPT-LUKS1-", sizeof ("CRYPT-LUKS1-") - 1) == 0
+      || strncmp (uuid, "CRYPT-LUKS2-", sizeof ("CRYPT-LUKS2-") - 1) == 0)
       && lastsubdev)
     {
       char *grdev = grub_util_get_grub_dev (lastsubdev);
-- 
2.35.1