In commit 2d8c0f8d40b5 ("options: decrypt LUKS-on-LV devices",
2022-02-28), in order to keep that change as contained as possible, we
didn't modify the naming scheme of those decrypted LUKS devices that
originated directly from partitions -- we passed "name_decrypted_by_uuid =
false" for partitions fetched with guestfs_list_partitions().

Turns out that this is exactly what prevents us from decrypting the
following block device structure (seen in RHEL6 guests; for example one
installed from "RHEL-6.10-20180525.0-Server-x86_64-dvd1.iso"):

> NAME                                                 MAJ:MIN RM  SIZE RO TYPE 
>  MOUNTPOINT
> vda                                                  252:0    0    9G  0 disk
> ├─vda1                                               252:1    0    1G  0 part 
>  /boot
> ├─vda2                                               252:2    0    7G  0 part
> │ └─luks-37f5c9df-acda-4955-8cfd-872f0da5e35b (dm-0) 253:0    0    7G  0 
> crypt /
> └─vda3                                               252:3    0 1023M  0 part 
>  [SWAP]
> sr0                                                   11:0    1 1024M  0 rom

The problem is that we prefer (a) make_mapname() due to the LUKS header
residing directly on a partition, so we call the plaintext device
"/dev/mapper/cryptsda2"; however (b) "/etc/fstab" in the guest refers to
the same plaintext device by the standard, UUID-based
"/dev/mapper/luks-37f5c9df-acda-4955-8cfd-872f0da5e35b" pathname.
Therefore "inspect_get_mountpoints" in "libguestfs/daemon/inspect.ml"
returns the latter pathname -- which we can't mount.

Hardwire "name_decrypted_by_uuid = true" in "options/decrypt.c" -- by
which effort we can as well remove the "name_decrypted_by_uuid" parameter.

Testing: the libguestfs, guestfs-tools, and virt-v2v test suites (make
check) pass with this update. Furthermore, "guestfish -i", virt-inspector,
and virt-v2v now recognize the above blockdev / fs structure (and the
converted guest boots).

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1658128
Signed-off-by: Laszlo Ersek <[email protected]>
---
 options/decrypt.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/options/decrypt.c b/options/decrypt.c
index b899a0028620..1cd7b627e264 100644
--- a/options/decrypt.c
+++ b/options/decrypt.c
@@ -111,15 +111,15 @@ make_mapname (const char *device)
   }
 
   return mapname;
 }
 
 static bool
 decrypt_mountables (guestfs_h *g, const char * const *mountables,
-                    struct key_store *ks, bool name_decrypted_by_uuid)
+                    struct key_store *ks)
 {
   bool decrypted_some = false;
   const char * const *mnt_scan = mountables;
   const char *mountable;
 
   while ((mountable = *mnt_scan++) != NULL) {
     CLEANUP_FREE char *type = NULL;
@@ -144,16 +144,15 @@ decrypt_mountables (guestfs_h *g, const char * const 
*mountables,
     /* Grab the keys that we should try with this device, based on device name,
      * or UUID (if any).
      */
     keys = get_keys (ks, mountable, uuid);
     assert (keys[0] != NULL);
 
     /* Generate a node name for the plaintext (decrypted) device node. */
-    if (!name_decrypted_by_uuid || uuid == NULL ||
-        asprintf (&mapname, "luks-%s", uuid) == -1)
+    if (uuid == NULL || asprintf (&mapname, "luks-%s", uuid) == -1)
       mapname = make_mapname (mountable);
 
     /* Try each key in turn. */
     key_scan = (const char * const *)keys;
     while ((key = *key_scan++) != NULL) {
       int r;
 
@@ -188,20 +187,19 @@ inspect_do_decrypt (guestfs_h *g, struct key_store *ks)
   CLEANUP_FREE_STRING_LIST char **partitions = guestfs_list_partitions (g);
   CLEANUP_FREE_STRING_LIST char **lvs = NULL;
   bool need_rescan;
 
   if (partitions == NULL)
     exit (EXIT_FAILURE);
 
-  need_rescan = decrypt_mountables (g, (const char * const *)partitions, ks,
-                                    false);
+  need_rescan = decrypt_mountables (g, (const char * const *)partitions, ks);
 
   if (need_rescan) {
     if (guestfs_lvm_scan (g, 1) == -1)
       exit (EXIT_FAILURE);
   }
 
   lvs = guestfs_lvs (g);
   if (lvs == NULL)
     exit (EXIT_FAILURE);
-  decrypt_mountables (g, (const char * const *)lvs, ks, true);
+  decrypt_mountables (g, (const char * const *)lvs, ks);
 }

base-commit: ab708d11d832457d2a0c74e7a6d8c219a4fdd90f
-- 
2.19.1.3.g30247aa5d201

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