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[PATCH 2/2] devmapper/getroot: Set up cheated LUKS2 cryptodisk mount fro
From: |
Josselin Poiret |
Subject: |
[PATCH 2/2] devmapper/getroot: Set up cheated LUKS2 cryptodisk mount from DM parameters |
Date: |
Thu, 9 Dec 2021 18:38:53 +0100 |
This lets a LUKS2 cryptodisk have all the cipher, hash, and sizes
filled out, otherwise they wouldn't be initialized if cheat mounted.
---
grub-core/osdep/devmapper/getroot.c | 51 ++++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/grub-core/osdep/devmapper/getroot.c
b/grub-core/osdep/devmapper/getroot.c
index ad1daf9c8..574d07a20 100644
--- a/grub-core/osdep/devmapper/getroot.c
+++ b/grub-core/osdep/devmapper/getroot.c
@@ -51,6 +51,8 @@
#include <grub/emu/misc.h>
#include <grub/emu/hostdisk.h>
+#include <grub/cryptodisk.h>
+
static int
grub_util_open_dm (const char *os_dev, struct dm_tree **tree,
struct dm_tree_node **node)
@@ -183,7 +185,6 @@ grub_util_pull_devmapper (const char *os_dev)
&& lastsubdev)
{
char *grdev = grub_util_get_grub_dev (lastsubdev);
- dm_tree_free (tree);
if (grdev)
{
grub_err_t err;
@@ -191,7 +192,55 @@ grub_util_pull_devmapper (const char *os_dev)
if (err)
grub_util_error (_("can't mount encrypted volume `%s': %s"),
lastsubdev, grub_errmsg);
+ if (strncmp (uuid, "CRYPT-LUKS2-", sizeof ("CRYPT-LUKS2-") - 1) == 0)
+ {
+ /* set LUKS2 cipher and size from dm parameter, since it is not
+ possible to determine the correct ones without unlocking, as
+ there might be multiple segments. */
+ grub_disk_t source = grub_disk_open (grdev);
+ grub_cryptodisk_t cryptodisk =
grub_cryptodisk_get_by_source_disk (source);
+ grub_disk_close (source);
+ grub_addr_t start, length;
+ char *target_type = NULL;
+ char *params;
+ const char *name = dm_tree_node_get_name (node);
+ char *cipher, *cipher_mode;
+ struct dm_task *dmt;
+ grub_util_info ("creating dm task for `%s'", name);
+ if (!(dmt = dm_task_create (DM_DEVICE_TABLE)))
+ grub_util_error (_("can't create dm task DM_DEVICE_TABLE"));
+ if (!dm_task_set_name (dmt, name))
+ grub_util_error (_("can't set dm task name to `%s'"), name);
+ if (!dm_task_run (dmt))
+ grub_util_error (_("can't run dm task for `%s'"), name);
+ dm_get_next_target (dmt, NULL, &start, &length,
+ &target_type, ¶ms);
+ if (strncmp (target_type, "crypt", sizeof ("crypt")) != 0)
+ grub_util_error (_("dm target is not `crypt'"));
+
+ cryptodisk->total_sectors = length;
+ cryptodisk->log_sector_size = GRUB_LUKS1_LOG_SECTOR_SIZE;
+
+ char *seek_head, *c;
+ c = params;
+ if (!(seek_head = grub_memchr (c, '-', grub_strlen (c))))
+ grub_util_error (_("can't get cipher from dm task"));
+ cipher = grub_strndup (c, seek_head - c);
+
+ c = seek_head + 1;
+ if (!(seek_head = grub_memchr (c, ' ', grub_strlen (c))))
+ grub_util_error (_("can't get cipher mode from dm task"));
+ cipher_mode = grub_strndup (c, seek_head - c);
+
+ grub_cryptodisk_setcipher (cryptodisk, cipher, cipher_mode);
+
+ /* This is the only hash usable by PBKDF2, so set it as such */
+ cryptodisk->hash = grub_crypto_lookup_md_by_name ("sha256");
+
+ dm_task_destroy (dmt);
+ }
}
+ dm_tree_free (tree);
grub_free (grdev);
}
else
--
2.34.0