[PATCH manager 4/4] fix #8169: api: backup: extract config: fix regression with backup type check

[Fiona Ebner <f.ebner@proxmox.com>]

Commit c7d53321 ("backup: extractconfig: clean early error for
non-guest backup") introduced a regression for guest backups without a
guest ID: it is no longer possible to extract the configuration from
such backups. Before, there was a Perl warning about the uninitialized
ID and the permission check would need to pass for 'VM.Backup' on
'/vms', but extraction was possible and it was relied on in practice,
see the regression report.

Avoid the early check for a guest ID, which does not cover (e.g.
manually renamed) guest backups without a guest ID. The storage layer
already checks the backup type later. In particular, the
extract_vzdump_config() function has three branches:

1. PBS: the PBS plugin's extract_vzdump_config() checks that the
   backup's format is either 'pbs-vm' or 'pbs-ct'.
2. backup provider: only guest backups are part of the backup provider
   API. It is the implemenation's responsibility to avoid exposing
   other content, in particular via archive_get_guest_config() here.
3. path-based vzdump backup: the backup type is checked via
   archive_info() to be one of 'lxc', 'openvz' or 'qemu'.

Fixes: c7d53321 ("backup: extractconfig: clean early error for non-guest backup")
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 PVE/API2/VZDump.pm | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/PVE/API2/VZDump.pm b/PVE/API2/VZDump.pm
index 98caf1d9..62ca153c 100644
--- a/PVE/API2/VZDump.pm
+++ b/PVE/API2/VZDump.pm
@@ -303,13 +303,6 @@ __PACKAGE__->register_method({
             $rpcenv, $authuser, $storage_cfg, undef, $volume, 'backup',
         );
 
-        if (PVE::Storage::parse_volume_id($volume, 1)) {
-            my (undef, undef, $ownervm) = PVE::Storage::parse_volname($storage_cfg, $volume);
-            if (!defined($ownervm)) {
-                die "unable to extract configuration for '$volume' - not a guest backup\n";
-            }
-        }
-
         return PVE::Storage::extract_vzdump_config($storage_cfg, $volume);
     },
 });
-- 
2.47.3