Re: [pve-devel] [PATCH qemu-server v9 1/1] api: update: improve tag privilege check

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

some nits, but really, just read the container patch response instead
;-)

On Mon, Nov 14, 2022 at 10:43:49AM +0100, Dominik Csapak wrote:
> 'normal' tags require 'VM.Config.Options' on '/vm/<vmid>', but not
> allowed tags (either limited with 'user-tag-access' or 'privileged-tags'
> in the datacenter config) require 'Sys.Modify' on '/'
> 
> this patch implements the proper checks on adding/editing/deleting
> these permissions
> 
> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
> changes from v8:
> * adapt to 'get_allowed_tags'
> * cache privilege checks (so we don't have to do it when many tags change)
>  PVE/API2/Qemu.pm | 53 +++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 52 insertions(+), 1 deletion(-)
> 
> diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
> index 30348e6..269451c 100644
> --- a/PVE/API2/Qemu.pm
> +++ b/PVE/API2/Qemu.pm
> @@ -539,7 +539,6 @@ my $generaloptions = {
>      'startup' => 1,
>      'tdf' => 1,
>      'template' => 1,
> -    'tags' => 1,
>  };
>  
>  my $vmpoweroptions = {
> @@ -609,6 +608,7 @@ my $check_vm_modify_config_perm = sub {
>  	next if PVE::QemuServer::is_valid_drivename($opt);
>  	next if $opt eq 'cdrom';
>  	next if $opt =~ m/^(?:unused|serial|usb)\d+$/;
> +	next if $opt eq 'tags';
>  
>  
>  	if ($cpuoptions->{$opt} || $opt =~ m/^numa\d+$/) {
> @@ -1631,6 +1631,31 @@ my $update_vm_api  = sub {
>  		}
>  	    };
>  
> +	    my $allowed_tags;
> +	    my $privileged_tags;
> +	    my $freeform;
> +	    my $privileged_user = $rpcenv->check($authuser, '/', ['Sys.Modify'], 1);
> +	    my $has_config_options =
> +		$rpcenv->check_vm_perm($authuser, $vmid, undef, ['VM.Config.Options'], 1);
> +
> +	    my $check_tag_perms = sub {

^ See the container patch

> +		my ($tag) = @_;
> +
> +		return if $privileged_user;
> +
> +		$rpcenv->check_vm_perm($authuser, $vmid, undef, ['VM.Config.Options'])
> +		    if !$has_config_options;
> +
> +		if (!defined($allowed_tags) && !defined($privileged_tags) && !defined($freeform)) {
> +		    ($allowed_tags, $privileged_tags, $freeform)
> +			= PVE::DataCenterConfig::get_allowed_tags($rpcenv, $authuser);
> +		}
> +
> +		if ((!$allowed_tags->{$tag} && !$freeform) || $privileged_tags->{$tag}) {
> +		    die "'Sys.Modify' required on '/' for modifying tag $tag\n" if !$privileged_user;
> +		}
> +	    };
> +
>  	    foreach my $opt (@delete) {
>  		$modified->{$opt} = 1;
>  		$conf = PVE::QemuConfig->load_config($vmid); # update/reload
> @@ -1689,6 +1714,13 @@ my $update_vm_api  = sub {
>  		    }
>  		    PVE::QemuConfig->add_to_pending_delete($conf, $opt, $force);
>  		    PVE::QemuConfig->write_config($vmid, $conf);
> +		} elsif ($opt eq 'tags') {
> +		    foreach my $tag (PVE::Tools::split_list($val)) {
> +			check_tag_perms->($tag);
> +		    }
> +
> +		    delete $conf->{$opt};
> +		    PVE::QemuConfig->write_config($vmid, $conf);
>  		} else {
>  		    PVE::QemuConfig->add_to_pending_delete($conf, $opt, $force);
>  		    PVE::QemuConfig->write_config($vmid, $conf);
> @@ -1748,6 +1780,25 @@ my $update_vm_api  = sub {
>  		    } elsif ($authuser ne 'root@pam') {
>  			die "only root can modify '$opt' config for real devices\n";
>  		    }
> +		    $conf->{pending}->{$opt} = $param->{$opt};
> +		} elsif ($opt eq 'tags') {
> +		    my $old_tags = {};
> +		    my $new_tags = {};
> +
> +		    map { $old_tags->{$_} += 1 } PVE::Tools::split_list($conf->{$opt} // '');
> +		    map { $new_tags->{$_} += 1 } PVE::Tools::split_list($param->{$opt});

^ See the container patch

> +
> +		    my $check_tags = sub {
> +			my ($a, $b) = @_;
> +			foreach my $tag (keys %$a) {
> +			    next if ($b->{$tag} // 0) == ($a->{$tag} // 0);
> +			    $check_tag_perms->($tag);
> +			}
> +		    };
> +
> +		    $check_tags->($old_tags, $new_tags);
> +		    $check_tags->($new_tags, $old_tags);
> +
>  		    $conf->{pending}->{$opt} = $param->{$opt};
>  		} else {
>  		    $conf->{pending}->{$opt} = $param->{$opt};
> -- 
> 2.30.2