[pve-devel] [PATCH v3 container 15/17] fix #2582: api: add checks for 'SuperUser' privilege for root-only options

[Oguz Bektas <o.bektas@proxmox.com>]

this way we can allow regular users to act as superuser on specific
paths by giving them the (new) builtin 'SuperAdministrator' role or a
custom role with the 'SuperUser' privilege

Signed-off-by: Oguz Bektas <o.bektas@proxmox.com>
---
v2->v3:
* update comments
* drop shortcuts for 'root@pam', just check for SU privilege

 src/PVE/API2/LXC.pm        | 19 +++++++++----------
 src/PVE/API2/LXC/Config.pm |  2 +-
 src/PVE/API2/LXC/Status.pm | 12 ++++++++----
 src/PVE/LXC.pm             | 21 ++++++++++++---------
 src/PVE/LXC/Create.pm      |  2 +-
 5 files changed, 31 insertions(+), 25 deletions(-)

diff --git a/src/PVE/API2/LXC.pm b/src/PVE/API2/LXC.pm
index ea4827f..4517b99 100644
--- a/src/PVE/API2/LXC.pm
+++ b/src/PVE/API2/LXC.pm
@@ -258,7 +258,7 @@ __PACKAGE__->register_method({
 	    $skip_fw_config_restore = 1;
 
 	    # error out if a user tries to change from unprivileged to privileged
-	    # explicit change is checked here, implicit is checked down below or happening in root-only paths
+	    # explicit change is checked here, implicit is checked down below or happening in superuser-only paths
 	    my $conf = PVE::LXC::Config->load_config($vmid);
 	    if ($conf->{unprivileged} && defined($unprivileged) && !$unprivileged) {
 		raise_perm_exc("cannot change from unprivileged to privileged without VM.Allocate");
@@ -312,7 +312,7 @@ __PACKAGE__->register_method({
 
 	my $conf = {};
 
-	my $is_root = $authuser eq 'root@pam';
+	my $is_superuser = $rpcenv->check($authuser, "/vms/$vmid", ['SuperUser'], 1);
 
 	my $no_disk_param = {};
 	my $mp_param = {};
@@ -347,8 +347,8 @@ __PACKAGE__->register_method({
 	    my $mp = $mountpoint->{mp};
 
 	    if ($mountpoint->{type} ne 'volume') { # bind or device
-		die "Only root can pass arbitrary filesystem paths.\n"
-		    if !$is_root;
+		die "Only superusers can pass arbitrary filesystem paths.\n"
+		    if !$is_superuser;
 	    } else {
 		my ($sid, $volname) = PVE::Storage::parse_volume_id($volid);
 		&$check_and_activate_storage($sid);
@@ -384,11 +384,11 @@ __PACKAGE__->register_method({
 
 			$was_template = delete $orig_conf->{template};
 
-			# When we're root call 'restore_configuration' with restricted=0,
+			# call 'restore_configuration' with restricted=0 when we have superuser,
 			# causing it to restore the raw lxc entries, among which there may be
 			# 'lxc.idmap' entries. We need to make sure that the extracted contents
 			# of the container match up with the restored configuration afterwards:
-			$conf->{lxc} = $orig_conf->{lxc} if $is_root;
+			$conf->{lxc} = $orig_conf->{lxc} if $is_superuser;
 
 			$conf->{unprivileged} = $orig_conf->{unprivileged}
 			    if !defined($unprivileged) && defined($orig_conf->{unprivileged});
@@ -422,8 +422,7 @@ __PACKAGE__->register_method({
 				my $type = $mountpoint->{type};
 				die "restoring rootfs to $type mount is only possible by specifying -rootfs manually!\n"
 				    if ($ms eq 'rootfs');
-				die "restoring '$ms' to $type mount is only possible for root\n"
-				    if !$is_root;
+				die "restoring '$ms' to $type mount is only possible for superusers\n" if !$is_superuser;
 
 				if ($mountpoint->{backup}) {
 				    warn "WARNING - unsupported configuration!\n";
@@ -464,7 +463,7 @@ __PACKAGE__->register_method({
 
 		    if ($restore) {
 			print "merging backed-up and given configuration..\n";
-			PVE::LXC::Create::restore_configuration($vmid, $storage_cfg, $archive, $rootdir, $conf, !$is_root, $unique, $skip_fw_config_restore);
+			PVE::LXC::Create::restore_configuration($vmid, $storage_cfg, $archive, $rootdir, $conf, !$is_superuser, $unique, $skip_fw_config_restore);
 			my $lxc_setup = PVE::LXC::Setup->new($conf, $rootdir);
 			$lxc_setup->template_fixup($conf);
 		    } else {
@@ -2224,7 +2223,7 @@ __PACKAGE__->register_method({
 	    raise_param_exc({ 'target-vmid' => $msg, 'storage' => $msg });
 	} elsif ($target_vmid) {
 	    $rpcenv->check_vm_perm($authuser, $target_vmid, undef, ['VM.Config.Disk'])
-		if $authuser ne 'root@pam';
+		if $authuser ne 'root@pam'; # no need to check for root@pam
 
 	    if ($vmid eq $target_vmid) {
 		my $msg = "must be different than source VMID to move disk to another container";
diff --git a/src/PVE/API2/LXC/Config.pm b/src/PVE/API2/LXC/Config.pm
index 1fec048..6278b8a 100644
--- a/src/PVE/API2/LXC/Config.pm
+++ b/src/PVE/API2/LXC/Config.pm
@@ -99,7 +99,7 @@ __PACKAGE__->register_method({
     description => "Set container options.",
     permissions => {
 	check => ['perm', '/vms/{vmid}', $vm_config_perm_list, any => 1],
-	description => 'non-volume mount points in rootfs and mp[n] are restricted to root@pam',
+	description => 'non-volume mount points in rootfs and mp[n] are restricted to superusers',
     },
     parameters => {
 	additionalProperties => 0,
diff --git a/src/PVE/API2/LXC/Status.pm b/src/PVE/API2/LXC/Status.pm
index f7e3128..ecd77e5 100644
--- a/src/PVE/API2/LXC/Status.pm
+++ b/src/PVE/API2/LXC/Status.pm
@@ -150,9 +150,11 @@ __PACKAGE__->register_method({
 	my $node = extract_param($param, 'node');
 	my $vmid = extract_param($param, 'vmid');
 
+	my $is_superuser = $rpcenv->check($authuser, "/vms/$vmid", ['SuperUser'], 1);
+
 	my $skiplock = extract_param($param, 'skiplock');
-	raise_param_exc({ skiplock => "Only root may use this option." })
-	    if $skiplock && $authuser ne 'root@pam';
+	raise_param_exc({ skiplock => "Only superusers may use this option." })
+	    if $skiplock && !$is_superuser;
 
 	die "CT $vmid already running\n" if PVE::LXC::check_running($vmid);
 
@@ -234,9 +236,11 @@ __PACKAGE__->register_method({
 	my $node = extract_param($param, 'node');
 	my $vmid = extract_param($param, 'vmid');
 
+	my $is_superuser = $rpcenv->check($authuser, "/vms/$vmid", ['SuperUser'], 1);
+
 	my $skiplock = extract_param($param, 'skiplock');
-	raise_param_exc({ skiplock => "Only root may use this option." })
-	    if $skiplock && $authuser ne 'root@pam';
+	raise_param_exc({ skiplock => "Only superusers may use this option." })
+	    if $skiplock && !$is_superuser;
 
 	die "CT $vmid not running\n" if !PVE::LXC::check_running($vmid);
 
diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
index fe63087..c93b314 100644
--- a/src/PVE/LXC.pm
+++ b/src/PVE/LXC.pm
@@ -1254,7 +1254,10 @@ sub template_create {
 sub check_ct_modify_config_perm {
     my ($rpcenv, $authuser, $vmid, $pool, $oldconf, $newconf, $delete, $unprivileged) = @_;
 
-    return 1 if $authuser eq 'root@pam';
+    return 1 if $authuser eq 'root@pam'; # early exit for root@pam
+
+    my $is_superuser = $rpcenv->check($authuser, "/vms/$vmid", ['SuperUser'], 1);
+
     my $storage_cfg = PVE::Storage::config();
 
     my $check = sub {
@@ -1265,8 +1268,8 @@ sub check_ct_modify_config_perm {
 	    $rpcenv->check_vm_perm($authuser, $vmid, $pool, ['VM.Config.Disk']);
 	    return if $delete;
 	    my $data = PVE::LXC::Config->parse_volume($opt, $newconf->{$opt});
-	    raise_perm_exc("mount point type $data->{type} is only allowed for root\@pam")
-		if $data->{type} ne 'volume';
+	    raise_perm_exc("mount point type $data->{type} is only allowed for superusers")
+		if $data->{type} ne 'volume' && !$is_superuser;
 	    my $volid = $data->{volume};
 	    if ($volid =~ $NEW_DISK_RE) {
 		my $sid = $1;
@@ -1287,8 +1290,8 @@ sub check_ct_modify_config_perm {
 		 $opt eq 'searchdomain' || $opt eq 'hostname') {
 	    $rpcenv->check_vm_perm($authuser, $vmid, $pool, ['VM.Config.Network']);
 	} elsif ($opt eq 'features') {
-	    raise_perm_exc("changing feature flags for privileged container is only allowed for root\@pam")
-		if !$unprivileged;
+	    raise_perm_exc("changing feature flags for privileged container is only allowed for superusers")
+		if !$unprivileged && !$is_superuser;
 
 	    my $nesting_changed = 0;
 	    my $other_changed = 0;
@@ -1326,13 +1329,13 @@ sub check_ct_modify_config_perm {
 		    $other_changed = 1;
 		}
 	    }
-	    raise_perm_exc("changing feature flags (except nesting) is only allowed for root\@pam")
-		if $other_changed;
+	    raise_perm_exc("changing feature flags (except nesting) is only allowed for superusers")
+		if $other_changed && !$is_superuser;
 	    $rpcenv->check_vm_perm($authuser, $vmid, $pool, ['VM.Allocate'])
 		if $nesting_changed;
 	} elsif ($opt eq 'hookscript') {
-	    # For now this is restricted to root@pam
-	    raise_perm_exc("changing the hookscript is only allowed for root\@pam");
+	    raise_perm_exc("changing the hookscript is only allowed for superusers")
+		if !$is_superuser;
 	} else {
 	    $rpcenv->check_vm_perm($authuser, $vmid, $pool, ['VM.Config.Options']);
 	}
diff --git a/src/PVE/LXC/Create.pm b/src/PVE/LXC/Create.pm
index 460df57..4602678 100644
--- a/src/PVE/LXC/Create.pm
+++ b/src/PVE/LXC/Create.pm
@@ -331,7 +331,7 @@ sub sanitize_and_merge_config {
 	if ($key eq 'lxc' && $restricted) {
 	    my $lxc_list = $oldconf->{'lxc'};
 
-	    my $msg = "skipping custom lxc options, restore manually as root:\n";
+	    my $msg = "skipping custom lxc options, restore manually as superuser:\n";
 	    $msg .= "--------------------------------\n";
 	    foreach my $lxc_opt (@$lxc_list) {
 		$msg .= "$lxc_opt->[0]: $lxc_opt->[1]\n"
-- 
2.30.2