[pve-devel] [PATCH v2 firewall] Don't change external ebtables rules

Wolfgang Bumiller w.bumiller at proxmox.com
Fri May 25 11:15:49 CEST 2018


Looks good. Some more comments inline.

On Wed, May 23, 2018 at 07:22:08PM +0200, Stoiko Ivanov wrote:
>   * Fixes #1764
>   * Introduces ebtables_enable option to cluster config
>   * All ebtables chains not created by PVE are left in place
> 
> Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
> ---
> Changes from V1:
> * externally defined rules (those not in chains matching
>   $pve_ebtables_chainname_regex) are ignored (taken and restored as is)
> * setting ebtables_enable to 1 in the cluster config now cleans the ebtable
>   rules generated by PVE.
> 
> I'm not too fond of the introduced code duplication
> (get_ebtables_ruleset_status), but since we need the actual rule texts from
> the ebtables output in this case as well it seemed like a fair compromise
> (the alternative being a quite larger refactoring of the other parts which use
> get_ruleset_status.
> 
> 
> 
> src/PVE/Firewall.pm | 100 ++++++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 73 insertions(+), 27 deletions(-)
> 
> diff --git a/src/PVE/Firewall.pm b/src/PVE/Firewall.pm
> index 96cf9bd..56b99c4 100644
> --- a/src/PVE/Firewall.pm
> +++ b/src/PVE/Firewall.pm
> @@ -1827,11 +1827,12 @@ sub ipset_get_chains {
>      return $res;
>  }
>  
> +my $pve_ebtables_chainname_regex = qr/PVEFW-\S+|(?:tab|veth)\d+i\d+-(?:IN|OUT)/;
> +
>  sub ebtables_get_chains {
>  
>      my $res = {};
>      my $chains = {};
> -
>      my $parser = sub {
>  	my $line = shift;
>  	return if $line =~ m/^#/;
> @@ -1839,15 +1840,11 @@ sub ebtables_get_chains {
>  	if ($line =~ m/^:(\S+)\s\S+$/) {
>  	    # Make sure we know chains exist even if they're empty.
>  	    $chains->{$1} //= [];
> -	} elsif ($line =~ m/^(?:\S+)\s(PVEFW-\S+)\s(?:\S+).*/) {
> +	} elsif ($line =~ m/^(?:\S+)\s($pve_ebtables_chainname_regex)\s(?:\S+).*/) {
>  	    my $chain = $1;
>  	    $line =~ s/\s+$//;
>  	    push @{$chains->{$chain}}, $line;

Looks like the 3 lines up here ^
...

> -	} elsif ($line =~ m/^(?:\S+)\s(tap\d+i\d+-(:?IN|OUT))\s(?:\S+).*/) {
> -	    my $chain = $1;
> -	    $line =~ s/\s+$//;
> -	    push @{$chains->{$chain}}, $line;
> -	} elsif ($line =~ m/^(?:\S+)\s(veth\d+i\d+-(:?IN|OUT))\s(?:\S+).*/) {
> +	} elsif ($line =~ m/^(?:\S+)\s(\S+)\s(?:\S+).*/) {
>  	    my $chain = $1;
>  	    $line =~ s/\s+$//;
>  	    push @{$chains->{$chain}}, $line;

... are the same as these ^
so we could merge them.

> @@ -1858,10 +1855,10 @@ sub ebtables_get_chains {
>      };
>  
>      run_command("/sbin/ebtables-save", outfunc => $parser);
> -
> -    # compute digest for each chain
> +    # compute digest for each chain and store rules as well
>      foreach my $chain (keys %$chains) {
> -	$res->{$chain} = iptables_chain_digest($chains->{$chain});
> +	$res->{$chain}->{'rules'} = $chains->{$chain};
> +	$res->{$chain}->{'digest'} = iptables_chain_digest($chains->{$chain});
>      }
>      return $res;
>  }
> @@ -2667,6 +2664,9 @@ sub parse_clusterfw_option {
>  	if (($value > 1) && ((time() - $value) > 60)) {
>  	    $value = 0
>  	}
> +    } elsif ($line =~ m/^(ebtables_enable):\s*(0|1)\s*$/i) {
> +	$opt = lc($1);
> +	$value = int($2);
>      } elsif ($line =~ m/^(policy_(in|out)):\s*(ACCEPT|DROP|REJECT)\s*$/i) {
>  	$opt = lc($1);
>  	$value = uc($3);
> @@ -3422,7 +3422,7 @@ sub compile {
>  	$vmfw_configs = read_vm_firewall_configs($cluster_conf, $vmdata, undef, $verbose);
>      }
>  
> -    return ({},{},{}) if !$cluster_conf->{options}->{enable};
> +    return ({},{},{},{}) if !$cluster_conf->{options}->{enable};
>  
>      my $localnet;
>      if ($cluster_conf->{aliases}->{local_network}) {
> @@ -3431,7 +3431,7 @@ sub compile {
>  	my $localnet_ver;
>  	($localnet, $localnet_ver) = parse_ip_or_cidr(local_network() || '127.0.0.0/8');
>  
> -	$cluster_conf->{aliases}->{local_network} = { 
> +	$cluster_conf->{aliases}->{local_network} = {
>  	    name => 'local_network', cidr => $localnet, ipversion => $localnet_ver };
>      }
>  
> @@ -3657,13 +3657,14 @@ sub compile_ipsets {
>  sub compile_ebtables_filter {
>      my ($cluster_conf, $hostfw_conf, $vmfw_configs, $vmdata, $verbose) = @_;
>  
> -    return ({}, {}) if !$cluster_conf->{options}->{enable};
> +    if (!($cluster_conf->{options}->{ebtables_enable} // 1)) {
> +	return {};
> +    }
>  
>      my $ruleset = {};
>  
>      ruleset_create_chain($ruleset, "PVEFW-FORWARD");
>  
> -
>      ruleset_create_chain($ruleset, "PVEFW-FWBR-OUT");
>      #for ipv4 and ipv6, check macaddress in iptables, so we use conntrack 'ESTABLISHED', to speedup rules
>      ruleset_addrule($ruleset, 'PVEFW-FORWARD', '-p IPv4', '-j ACCEPT');
> @@ -3848,6 +3849,50 @@ sub get_ruleset_cmdlist {
>  
>      return wantarray ? ($cmdlist, $changes) : $cmdlist;
>  }

Missing newline

> +sub get_ebtables_ruleset_status {
> +    my ($ruleset, $active_chains, $digest_fn, $verbose) = @_;
> +
> +    my $statushash = {};
> +
> +    foreach my $chain (sort keys %$ruleset) {
> +	my $digest = &$digest_fn($ruleset->{$chain});
> +
> +	$statushash->{$chain}->{digest} = $digest;
> +
> +	my $olddigest = $active_chains->{$chain}->{digest};
> +	if (defined($olddigest) && ($olddigest eq $digest) ) {
> +	    $statushash->{$chain}->{action} = 'exists';
> +	} else {
> +	    $statushash->{$chain}->{action} = 'create/update';
> +	}
> +	$statushash->{$chain}->{rules} = $ruleset->{$chain};
> +	if ($verbose) {
> +	    print "$statushash->{$chain}->{action} $chain ($digest)\n";
> +	    foreach my $cmd (@{$ruleset->{$chain}}) {
> +		print "\t$cmd\n";
> +	    }
> +	}
> +    }
> +
> +    foreach my $chain (sort keys %$active_chains) {
> +	my $action;
> +	if (!defined($ruleset->{$chain})) {
> +	    if ($chain =~ m/$pve_ebtables_chainname_regex/) {

I think this is the only actually required difference to
get_ruleset_status - maybe we can just optionally pass the regex or a
flag to it to trigger this behavior?
If we can do that, maybe also do the same $verbose check cleanup you did
above during the duplication to the other function ;-)

> +		$action = 'delete';
> +	    } else {
> +		$action = 'ignore';
> +	    }
> +	    $statushash->{$chain}->{action} = $action;
> +	    my $digest = $active_chains->{$chain}->{digest};
> +	    $statushash->{$chain}->{digest} = $digest;
> +	    $statushash->{$chain}->{rules} = $active_chains->{$chain}->{rules};
> +	    print "$action $chain ($digest)\n" if $verbose;
> +	}
> +    }
> +
> +    return $statushash;
> +}
> +

one too many newlines ;-)

>  
>  sub get_ebtables_cmdlist {
>      my ($ruleset, $verbose) = @_;
> @@ -3856,28 +3901,29 @@ sub get_ebtables_cmdlist {
>      my $cmdlist = "*filter\n";
>  
>      my ($active_chains, $hooks) = ebtables_get_chains();
> -    my $statushash = get_ruleset_status($ruleset, $active_chains, \&iptables_chain_digest, $verbose);
> +    my $statushash = get_ebtables_ruleset_status($ruleset, $active_chains, \&iptables_chain_digest, $verbose);
>  
>      # create chains first
> -    foreach my $chain (sort keys %$ruleset) {
> -	my $stat = $statushash->{$chain};
> -	die "internal error" if !$stat;
> +    foreach my $chain (sort keys %$statushash) {
> +	next if ($statushash->{$chain}->{action} eq 'delete');
>  	$cmdlist .= ":$chain ACCEPT\n";
>      }
>  
> -    if ($ruleset->{'PVEFW-FORWARD'}) {
> -	$cmdlist .= "-A FORWARD -j PVEFW-FORWARD\n";
> -    }
> -
> -    foreach my $chain (sort keys %$ruleset) {
> +    foreach my $chain (sort keys %$statushash) {
>  	my $stat = $statushash->{$chain};
> -	die "internal error" if !$stat;
> -	$changes = 1 if ($stat->{action} ne 'exists');
> +	next if ($stat->{action} eq 'delete');
> +	$changes = 1 if ($stat->{action} !~ 'ignore|exists');
>  

We could move the -A FORWARD string here:
    my $append_pve_to_forward = '-A FORWARD -j PVEFW-FORWARD';
(note the removed newline)

> -	foreach my $cmd (@{$ruleset->{$chain}}) {
> +	foreach my $cmd (@{$statushash->{$chain}->{'rules'}}) {
>  	    $cmdlist .= "$cmd\n";

Clear it here if we find the string:
    $append_pve_to_forward = '' if $cmd eq $append_pve_to_forward;

>  	}
>      }
> +    my $append_pve_to_forward = "-A FORWARD -j PVEFW-FORWARD\n";
> +    if ($ruleset->{'PVEFW-FORWARD'}) {

Check for ($append_pve_to_forward && $ruleset->...) here

> +	$cmdlist .= $append_pve_to_forward if $cmdlist !~ $append_pve_to_forward;

And skip the regex (which btw. would need \Q and \E around the variable.
The 'eq' checks should be more efficient than invoking the regex matcher
on a complete string I think?

> +    } else {
> +	$cmdlist =~ s/$append_pve_to_forward//;

(Also \Q and \E around the variable missing)

> +    }
>  
>      return wantarray ? ($cmdlist, $changes) : $cmdlist;
>  }
> @@ -4025,7 +4071,7 @@ sub apply_ruleset {
>      }
>  
>      my $active_ebtables_chains = ebtables_get_chains();
> -    my $ebtables_statushash = get_ruleset_status($ebtables_ruleset, $active_ebtables_chains, \&iptables_chain_digest, 0);
> +    my $ebtables_statushash = get_ebtables_ruleset_status($ebtables_ruleset, $active_ebtables_chains, \&iptables_chain_digest, 0);
>  
>      foreach my $chain (sort keys %$ebtables_ruleset) {
>  	my $stat = $ebtables_statushash->{$chain};
> -- 
> 2.11.0



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