[pve-devel] [PATCH v1 container 3/5] fix #2582: api: add checks for 'SuperUser' privilege for root-only options

[Fabian Grünbichler]

On February 8, 2022 2:10 pm, Oguz Bektas wrote:
> this way we can allow non-root users to act as a SU on specific
> root-only API paths by giving them the built-in SA role or a custom role
> with the SU privilege included.
> 
> Signed-off-by: Oguz Bektas <o.bektas at proxmox.com>
> ---
>  src/PVE/API2/LXC.pm        | 13 ++++++-------
>  src/PVE/API2/LXC/Status.pm |  8 ++++++--
>  src/PVE/LXC.pm             |  9 ++++++---
>  3 files changed, 18 insertions(+), 12 deletions(-)
> 
> diff --git a/src/PVE/API2/LXC.pm b/src/PVE/API2/LXC.pm
> index 7573814..b24e405 100644
> --- a/src/PVE/API2/LXC.pm
> +++ b/src/PVE/API2/LXC.pm
> @@ -295,7 +295,7 @@ __PACKAGE__->register_method({
>  
>  	my $conf = {};
>  
> -	my $is_root = $authuser eq 'root at pam';
> +	my $is_superuser = $authuser eq 'root at pam' || $rpcenv->check($authuser, "/vms/$vmid", ['SuperUser'], 1);
>  
>  	my $no_disk_param = {};
>  	my $mp_param = {};
> @@ -330,8 +330,8 @@ __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;

schema still has root-only in the description, both here and in the 
update path..

>  	    } else {
>  		my ($sid, $volname) = PVE::Storage::parse_volume_id($volid);
>  		&$check_and_activate_storage($sid);
> @@ -371,7 +371,7 @@ __PACKAGE__->register_method({
>  			# 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});
> @@ -405,8 +405,7 @@ __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 $type mount is only possible for root\n" if !$is_superuser;

still references root

>  
>  				if ($mountpoint->{backup}) {
>  				    warn "WARNING - unsupported configuration!\n";
> @@ -447,7 +446,7 @@ __PACKAGE__->register_method({
>  
>  		    if ($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 {
> diff --git a/src/PVE/API2/LXC/Status.pm b/src/PVE/API2/LXC/Status.pm
> index f7e3128..791cdc6 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 = $authuser eq 'root at pam' || $rpcenv->check($authuser, "/vms/$vmid", ['SuperUser'], 1);
> +
>  	my $skiplock = extract_param($param, 'skiplock');
>  	raise_param_exc({ skiplock => "Only root may use this option." })

nit: message needs updating (repeated a few times below)

> -	    if $skiplock && $authuser ne 'root at pam';
> +	    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 = $authuser eq 'root at pam' || $rpcenv->check($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 at pam';
> +	    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 b07d986..6b5125c 100644
> --- a/src/PVE/LXC.pm
> +++ b/src/PVE/LXC.pm
> @@ -1254,7 +1254,9 @@ sub template_create {
>  sub check_ct_modify_config_perm {
>      my ($rpcenv, $authuser, $vmid, $pool, $oldconf, $newconf, $delete, $unprivileged) = @_;
>  
> -    return 1 if $authuser eq 'root at pam';
> +    my $is_superuser = $authuser eq 'root at pam' || $rpcenv->check($authuser, "/vms/$vmid", ['SuperUser']);
> +    return 1 if $is_superuser;

so.. 'SuperUser' on its own should only skip those parts where root at pam 
was previously a requirement on top of other checks, but instead 
'SuperUser' can now modify the config however even with no other privs?

> +
>      my $storage_cfg = PVE::Storage::config();
>  
>      my $check = sub {
> @@ -1320,12 +1322,13 @@ sub check_ct_modify_config_perm {

here there is the non-volume part that is still root-only, with no 
comment about why that one is not switched to 'SuperUser'?

also, features for privileged containers is still root-only (should 
probably require VM.Allocate + SuperUser, when looking at the 
create/restore path).

>  		}
>  	    }
>  	    raise_perm_exc("changing feature flags (except nesting) is only allowed for root\@pam")

wrong message now

> -		if $other_changed;
> +		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 at pam
> -	    raise_perm_exc("changing the hookscript is only allowed for root\@pam");
> +	    raise_perm_exc("changing the hookscript is only allowed for root\@pam")
> +		if !$is_superuser;

comment, message and code don't agree

>  	} else {
>  	    $rpcenv->check_vm_perm($authuser, $vmid, $pool, ['VM.Config.Options']);
>  	}
> -- 
> 2.30.2
> 
> 
> 
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