[PATCH container v3 0/2] fix #7164: restore: apply password and ssh keys

[PATCH container v3 0/2] fix #7164: restore: apply password and ssh keys

[Elias Huhsovitz]

This patch series fixes Bug #7164. When restoring a container via
`pct restore`, the options `--password` and `--ssh-public-keys` are
silently ignored.

Patch 1/2 fixes the bug by introducing a new `post_restore_hook` to
the LXC setup plugin architecture. This hook applies the provided
credentials if they are provided.

Patch 2/2 adds a `check_systemd_nesting` call to the new
restore hook for consistency with container creation and cloning.
Note: This might cause a `die` in some edge cases and is not
essential to fixing bug #7164. Therefore consider patch 2/2
optional.

Changes v2 -> v3:
-----------------
* Split `check_systemd_nesting()` addition into optional second patch.
* Replace `defined` check for ssh keys with truthy check
  to match creation logic.
* Shorten commit message.
* Fix formatting in commit message.

Changes v1 -> v2:
-----------------
* Move logic into new function `post_restore_hook`.
* Do not call `post_create_hook` unconditionally.
* Conditionally call functions to:
    - set password
    - set ssh keys
* Call `check_systemd_nesting()` for pct restore.

Previous Versions
-----------------
v2: https://lore.proxmox.com/pve-devel/20260729082545.17885-1-e.huhsovitz@proxmox.com/
v1: https://lore.proxmox.com/pve-devel/20260716153959.183045-1-e.huhsovitz@proxmox.com/

Summary of Changes
------------------

Elias Huhsovitz (2):
  fix #7164: restore: apply password and ssh keys
  restore: check systemd nesting

 src/PVE/API2/LXC.pm            | 2 +-
 src/PVE/LXC/Setup.pm           | 9 +++++++++
 src/PVE/LXC/Setup/Base.pm      | 9 +++++++++
 src/PVE/LXC/Setup/Plugin.pm    | 5 +++++
 src/PVE/LXC/Setup/Unmanaged.pm | 4 ++++
 5 files changed, 28 insertions(+), 1 deletion(-)

-- 
2.47.3

[PATCH container v3 1/2] fix #7164: restore: apply password and ssh keys

[Elias Huhsovitz]

When restoring a container with `pct restore`, the `--password` and
`--ssh-public-keys` options are silently ignored. Previously, the API
endpoint only invoked setup hooks during initial container creation or
cloning.

Introduce a new `post_restore_hook` in the LXC setup plugin
architecture. This hook applies the provided credentials if they are
defined.

Move `template_fixup` to the `post_restore_hook`, matching the creation
logic.

Signed-off-by: Elias Huhsovitz <e.huhsovitz@proxmox.com>
---
 src/PVE/API2/LXC.pm            | 2 +-
 src/PVE/LXC/Setup.pm           | 8 ++++++++
 src/PVE/LXC/Setup/Base.pm      | 9 +++++++++
 src/PVE/LXC/Setup/Plugin.pm    | 5 +++++
 src/PVE/LXC/Setup/Unmanaged.pm | 4 ++++
 5 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/PVE/API2/LXC.pm b/src/PVE/API2/LXC.pm
index 22320ba..ad3b635 100644
--- a/src/PVE/API2/LXC.pm
+++ b/src/PVE/API2/LXC.pm
@@ -590,7 +590,7 @@ __PACKAGE__->register_method({
                         );
                         PVE::LXC::create_ifaces_ipams_ips($conf, $vmid) if $unique;
                         my $lxc_setup = PVE::LXC::Setup->new($conf, $rootdir);
-                        $lxc_setup->template_fixup($conf);
+                        $lxc_setup->post_restore_hook($password, $ssh_keys);
                     } else {
                         my $lxc_setup = PVE::LXC::Setup->new($conf, $rootdir); # detect OS
                         PVE::LXC::Config->write_config($vmid, $conf); # safe config (after OS detection)
diff --git a/src/PVE/LXC/Setup.pm b/src/PVE/LXC/Setup.pm
index d936af2..f94919b 100644
--- a/src/PVE/LXC/Setup.pm
+++ b/src/PVE/LXC/Setup.pm
@@ -329,6 +329,14 @@ sub post_create_hook {
     $self->check_systemd_nesting();
 }
 
+sub post_restore_hook {
+    my ($self, $root_password, $ssh_keys) = @_;
+
+    $self->protected_call(sub {
+        $self->{plugin}->post_restore_hook($self->{conf}, $root_password, $ssh_keys);
+    });
+}
+
 sub unified_cgroupv2_support {
     my ($self) = @_;
 
diff --git a/src/PVE/LXC/Setup/Base.pm b/src/PVE/LXC/Setup/Base.pm
index 567f9d6..bb75690 100644
--- a/src/PVE/LXC/Setup/Base.pm
+++ b/src/PVE/LXC/Setup/Base.pm
@@ -735,6 +735,15 @@ sub post_create_hook {
     # fixme: what else ?
 }
 
+sub post_restore_hook {
+    my ($self, $conf, $root_password, $ssh_keys) = @_;
+
+    $self->template_fixup($conf);
+
+    $self->set_user_password($conf, 'root', $root_password) if defined($root_password);
+    $self->set_user_authorized_ssh_keys($conf, 'root', $ssh_keys) if $ssh_keys;
+}
+
 # File access wrappers for container setup code.
 # NOTE: those are not direct part of the Plugin API (yet), avoid using them outside the child plugins
 # For user-namespace support these might need to take uid and gid maps into account.
diff --git a/src/PVE/LXC/Setup/Plugin.pm b/src/PVE/LXC/Setup/Plugin.pm
index 95a633f..6ba656b 100644
--- a/src/PVE/LXC/Setup/Plugin.pm
+++ b/src/PVE/LXC/Setup/Plugin.pm
@@ -99,4 +99,9 @@ sub post_create_hook {
     croak "implement me in sub-class";
 }
 
+sub post_restore_hook {
+    my ($self, $conf, $root_password, $ssh_keys) = @_;
+    croak "implement me in sub-class";
+}
+
 1;
diff --git a/src/PVE/LXC/Setup/Unmanaged.pm b/src/PVE/LXC/Setup/Unmanaged.pm
index b51be55..0b440cf 100644
--- a/src/PVE/LXC/Setup/Unmanaged.pm
+++ b/src/PVE/LXC/Setup/Unmanaged.pm
@@ -84,4 +84,8 @@ sub post_create_hook {
     my ($self, $conf, $root_password, $ssh_keys) = @_;
 }
 
+sub post_restore_hook {
+    my ($self, $conf, $root_password, $ssh_keys) = @_;
+}
+
 1;
-- 
2.47.3

[PATCH container v3 2/2] restore: check systemd nesting

[Elias Huhsovitz]

For consistency with `post_create_hook` and `post_clone_hook`, invoke
`check_systemd_nesting` at the end of `post_restore_hook`.

This provides early warnings to the user if they restore a modern
systemd-based container without the required `nesting` feature enabled,
preventing potential boot hangs and reducing troubleshooting time.

Signed-off-by: Elias Huhsovitz <e.huhsovitz@proxmox.com>
---
 src/PVE/LXC/Setup.pm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/PVE/LXC/Setup.pm b/src/PVE/LXC/Setup.pm
index f94919b..58cadba 100644
--- a/src/PVE/LXC/Setup.pm
+++ b/src/PVE/LXC/Setup.pm
@@ -335,6 +335,7 @@ sub post_restore_hook {
     $self->protected_call(sub {
         $self->{plugin}->post_restore_hook($self->{conf}, $root_password, $ssh_keys);
     });
+    $self->check_systemd_nesting();
 }
 
 sub unified_cgroupv2_support {
-- 
2.47.3