maybe better

firewall/rules_builder.go

@@ -47,9 +47,10 @@ type rule struct {
 	cidr    netip.Prefix
 	anyCIDR bool
 
-	// localCIDRs are the local addresses the rule allows, anyLocalCIDR allows all of them.
+	// localCIDR is the local addresses the rule allows, anyLocalCIDR allows all of them.
 	// Neither is set for a rule without a local cidr until the Table is built and it gets the default.
-	localCIDRs   []netip.Prefix
+	// localCIDR is shared by every localRules the rule is added to, so it's never changed, see localRules.add
+	localCIDR    *bart.Lite
 	anyLocalCIDR bool
 }
 
@@ -104,10 +105,17 @@ func (b *RulesBuilder) AddRule(incoming bool, proto uint8, startPort int32, endP
 // Build turns the rules into a Table for each direction, and hashes them. Rules without a local cidr allow
 // vpnNetworks when there are unsafe networks, otherwise any local address.
 func (b *RulesBuilder) Build(vpnNetworks, unsafeNetworks []netip.Prefix) Rules {
-	anyLocal := len(unsafeNetworks) == 0 || b.defaultLocalCIDRAny
+	var defaultLocal *bart.Lite
+	if len(unsafeNetworks) > 0 && !b.defaultLocalCIDRAny {
+		defaultLocal = new(bart.Lite)
+		for _, network := range vpnNetworks {
+			defaultLocal.Insert(network)
+		}
+	}
+
 	return Rules{
-		In:      b.in.build(anyLocal, vpnNetworks),
-		Out:     b.out.build(anyLocal, vpnNetworks),
+		In:      b.in.build(defaultLocal),
+		Out:     b.out.build(defaultLocal),
 		Hash:    hex.EncodeToString(b.ruleSHA.Sum(nil)),
 		HashFNV: b.ruleFNV.Sum32(),
 	}
@@ -139,7 +147,8 @@ func parseRule(startPort, endPort int32, groups []string, host, cidr, localCidr,
 		return rule{}, fmt.Errorf("local_cidr did not parse; %w", err)
 	}
 	if localCIDR.IsValid() {
-		r.localCIDRs = []netip.Prefix{localCIDR}
+		r.localCIDR = new(bart.Lite)
+		r.localCIDR.Insert(localCIDR)
 	}
 
 	return r, nil
@@ -157,42 +166,44 @@ func (tr *tableRules) add(proto uint8, r rule) {
 	}
 }
 
-// build turns the rules into a Table. Rules without a local cidr allow defaultLocalCIDRs,
-// or any local address when defaultLocalAny is set.
-func (tr *tableRules) build(defaultLocalAny bool, defaultLocalCIDRs []netip.Prefix) *Table {
-	add := func(pr portRules, rules []rule) {
-		for _, r := range rules {
-			if !r.anyLocalCIDR && r.localCIDRs == nil {
-				r.anyLocalCIDR, r.localCIDRs = defaultLocalAny, defaultLocalCIDRs
-			}
-			pr.add(r)
-		}
-	}
+// build turns the rules into a Table. Rules without a local cidr allow defaultLocal,
+// or any local address when defaultLocal is nil.
+func (tr *tableRules) build(defaultLocal *bart.Lite) *Table {
+	t := &Table{}
 
-	var anyProto portRules
-	if len(tr.anyRules) > 0 {
-		anyProto = portRules{}
-		add(anyProto, tr.anyRules)
+	// Every protocol starts out sharing the proto `any` rules, including protos[ProtoAny]
+	anyProto := newPortRules(defaultLocal, tr.anyRules)
+	for proto := range t.protos {
+		t.protos[proto] = anyProto
 	}
 
-	t := &Table{}
-	for proto := range t.protos {
-		rules := tr.protoRules[proto]
-		if len(rules) == 0 {
-			t.protos[proto] = anyProto
-			continue
+	// Protocols with rules of their own get a copy of the proto `any` rules too, so a packet only checks one set
+	for proto, rules := range tr.protoRules {
+		if len(rules) > 0 {
+			t.protos[proto] = newPortRules(defaultLocal, tr.anyRules, rules)
 		}
-
-		pr := portRules{}
-		add(pr, tr.anyRules)
-		add(pr, rules)
-		t.protos[proto] = pr
 	}
+
+	// ICMP and ICMPv6 share one set of rules, add keeps them together under ICMP
 	t.protos[iputil.IPProtocolICMPv6] = t.protos[iputil.IPProtocolICMP]
 
 	return t
 }
 
+// newPortRules builds portRules from each set of rules, or returns nil when there are none
+func newPortRules(defaultLocal *bart.Lite, ruleSets ...[]rule) portRules {
+	var pr portRules
+	for _, rules := range ruleSets {
+		for _, r := range rules {
+			if pr == nil {
+				pr = portRules{}
+			}
+			pr.add(r.withDefaultLocal(defaultLocal))
+		}
+	}
+	return pr
+}
+
 // parseCIDR parses a rule's cidr, which is empty, `any`, or a prefix
 func parseCIDR(s string) (prefix netip.Prefix, isAny bool, err error) {
 	switch s {
@@ -215,6 +226,16 @@ func (r rule) isAny() bool {
 	return slices.Contains(r.groups, "any") || r.host == "any" || r.anyCIDR
 }
 
+// withDefaultLocal returns r allowing defaultLocal, or any local address when defaultLocal is nil,
+// unless r has a local cidr of its own
+func (r rule) withDefaultLocal(defaultLocal *bart.Lite) rule {
+	if !r.anyLocalCIDR && r.localCIDR == nil {
+		r.anyLocalCIDR = defaultLocal == nil
+		r.localCIDR = defaultLocal
+	}
+	return r
+}
+
 func (pr portRules) add(r rule) {
 	for i := r.startPort; i <= r.endPort; i++ {
 		cr := pr[i]
@@ -285,11 +306,13 @@ func (lr *localRules) add(r rule) {
 		return
 	}
 
+	// Share the rule's local cidrs until another rule's need adding, then copy them instead of changing them
 	if lr.LocalCIDR == nil {
-		lr.LocalCIDR = new(bart.Lite)
+		lr.LocalCIDR = r.localCIDR
+		return
 	}
-	for _, prefix := range r.localCIDRs {
-		lr.LocalCIDR.Insert(prefix)
+	for prefix := range r.localCIDR.All() {
+		lr.LocalCIDR = lr.LocalCIDR.InsertPersist(prefix)
 	}
 }
 

firewall/rules_builder_test.go

@@ -0,0 +1,220 @@
+package firewall
+
+import (
+	"math"
+	"net/netip"
+	"testing"
+
+	"github.com/slackhq/nebula/iputil"
+	"github.com/slackhq/nebula/test"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRulesBuilder_AddRule(t *testing.T) {
+	l := test.NewLogger()
+
+	ti, err := netip.ParsePrefix("1.2.3.4/32")
+	require.NoError(t, err)
+
+	ti6, err := netip.ParsePrefix("fd12::34/128")
+	require.NoError(t, err)
+
+	rb := NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolTCP, 1, 1, []string{}, "", "", "", "", ""))
+	rules := rb.Build(nil, nil)
+	// An empty rule is any
+	assert.True(t, rules.In.protos[iputil.IPProtocolTCP][1].Any.Any.Any)
+	assert.Empty(t, rules.In.protos[iputil.IPProtocolTCP][1].Any.Groups)
+	assert.Empty(t, rules.In.protos[iputil.IPProtocolTCP][1].Any.Hosts)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolUDP, 1, 1, []string{"g1"}, "", "", "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.Nil(t, rules.In.protos[iputil.IPProtocolUDP][1].Any.Any)
+	assert.Contains(t, rules.In.protos[iputil.IPProtocolUDP][1].Any.Groups[0].Groups, "g1")
+	assert.Empty(t, rules.In.protos[iputil.IPProtocolUDP][1].Any.Hosts)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolICMP, 1, 1, []string{}, "h1", "", "", "", ""))
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolICMPv6, 1, 1, []string{}, "h2", "", "", "", ""))
+	rules = rb.Build(nil, nil)
+	//no matter what port is given for icmp, it should end up as "any"
+	assert.Nil(t, rules.In.protos[iputil.IPProtocolICMP][PortAny].Any.Any)
+	assert.Empty(t, rules.In.protos[iputil.IPProtocolICMP][PortAny].Any.Groups)
+	assert.Contains(t, rules.In.protos[iputil.IPProtocolICMP][PortAny].Any.Hosts, "h1")
+
+	// ICMP and ICMPv6 share one set of rules
+	assert.Contains(t, rules.In.protos[iputil.IPProtocolICMP][PortAny].Any.Hosts, "h2")
+	assert.Contains(t, rules.In.protos[iputil.IPProtocolICMPv6][PortAny].Any.Hosts, "h1")
+
+	// Any other protocol number gets its own rules
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, 47, 0, 0, []string{"g1"}, "", "", "", "", "")) // GRE
+	rules = rb.Build(nil, nil)
+	assert.Contains(t, rules.In.protos[47][PortAny].Any.Groups[0].Groups, "g1")
+	assert.Nil(t, rules.In.protos[iputil.IPProtocolTCP])
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 1, 1, []string{}, "", ti.String(), "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.Nil(t, rules.Out.protos[ProtoAny][1].Any.Any)
+	_, ok := rules.Out.protos[ProtoAny][1].Any.CIDR.Get(ti)
+	assert.True(t, ok)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 1, 1, []string{}, "", ti6.String(), "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.Nil(t, rules.Out.protos[ProtoAny][1].Any.Any)
+	_, ok = rules.Out.protos[ProtoAny][1].Any.CIDR.Get(ti6)
+	assert.True(t, ok)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 1, 1, []string{}, "", "", ti.String(), "", ""))
+	rules = rb.Build(nil, nil)
+	assert.NotNil(t, rules.Out.protos[ProtoAny][1].Any.Any)
+	ok = rules.Out.protos[ProtoAny][1].Any.Any.LocalCIDR.Get(ti)
+	assert.True(t, ok)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 1, 1, []string{}, "", "", ti6.String(), "", ""))
+	rules = rb.Build(nil, nil)
+	assert.NotNil(t, rules.Out.protos[ProtoAny][1].Any.Any)
+	ok = rules.Out.protos[ProtoAny][1].Any.Any.LocalCIDR.Get(ti6)
+	assert.True(t, ok)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolUDP, 1, 1, []string{"g1"}, "", "", "", "ca-name", ""))
+	rules = rb.Build(nil, nil)
+	assert.Contains(t, rules.In.protos[iputil.IPProtocolUDP][1].CANames, "ca-name")
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolUDP, 1, 1, []string{"g1"}, "", "", "", "", "ca-sha"))
+	rules = rb.Build(nil, nil)
+	assert.Contains(t, rules.In.protos[iputil.IPProtocolUDP][1].CAShas, "ca-sha")
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 0, 0, []string{}, "any", "", "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.True(t, rules.Out.protos[ProtoAny][0].Any.Any.Any)
+
+	rb = NewRulesBuilder(l)
+	anyIp, err := netip.ParsePrefix("0.0.0.0/0")
+	require.NoError(t, err)
+
+	require.NoError(t, rb.AddRule(false, ProtoAny, 0, 0, []string{}, "", anyIp.String(), "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.Nil(t, rules.Out.protos[ProtoAny][0].Any.Any)
+	table, ok := rules.Out.protos[ProtoAny][0].Any.CIDR.Lookup(netip.MustParseAddr("1.1.1.1"))
+	assert.True(t, table.Any)
+	table, ok = rules.Out.protos[ProtoAny][0].Any.CIDR.Lookup(netip.MustParseAddr("9::9"))
+	assert.False(t, ok)
+
+	rb = NewRulesBuilder(l)
+	anyIp6, err := netip.ParsePrefix("::/0")
+	require.NoError(t, err)
+
+	require.NoError(t, rb.AddRule(false, ProtoAny, 0, 0, []string{}, "", anyIp6.String(), "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.Nil(t, rules.Out.protos[ProtoAny][0].Any.Any)
+	table, ok = rules.Out.protos[ProtoAny][0].Any.CIDR.Lookup(netip.MustParseAddr("9::9"))
+	assert.True(t, table.Any)
+	table, ok = rules.Out.protos[ProtoAny][0].Any.CIDR.Lookup(netip.MustParseAddr("1.1.1.1"))
+	assert.False(t, ok)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 0, 0, []string{}, "", "any", "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.True(t, rules.Out.protos[ProtoAny][0].Any.Any.Any)
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 0, 0, []string{}, "", "", anyIp.String(), "", ""))
+	rules = rb.Build(nil, nil)
+	assert.False(t, rules.Out.protos[ProtoAny][0].Any.Any.Any)
+	assert.True(t, rules.Out.protos[ProtoAny][0].Any.Any.LocalCIDR.Lookup(netip.MustParseAddr("1.1.1.1")))
+	assert.False(t, rules.Out.protos[ProtoAny][0].Any.Any.LocalCIDR.Lookup(netip.MustParseAddr("9::9")))
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 0, 0, []string{}, "", "", anyIp6.String(), "", ""))
+	rules = rb.Build(nil, nil)
+	assert.False(t, rules.Out.protos[ProtoAny][0].Any.Any.Any)
+	assert.True(t, rules.Out.protos[ProtoAny][0].Any.Any.LocalCIDR.Lookup(netip.MustParseAddr("9::9")))
+	assert.False(t, rules.Out.protos[ProtoAny][0].Any.Any.LocalCIDR.Lookup(netip.MustParseAddr("1.1.1.1")))
+
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(false, ProtoAny, 0, 0, []string{}, "", "", "any", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.True(t, rules.Out.protos[ProtoAny][0].Any.Any.Any)
+
+	// Every protocol number is accepted
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, math.MaxUint8, 0, 0, []string{}, "", "", "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.True(t, rules.In.protos[math.MaxUint8][PortAny].Any.Any.Any)
+
+	// Test error conditions, a bad rule is reported when it's added
+	rb = NewRulesBuilder(l)
+	require.Error(t, rb.AddRule(true, ProtoAny, 10, 0, []string{}, "", "", "", "", ""))
+	require.Error(t, rb.AddRule(true, ProtoAny, 0, 0, []string{}, "", "junk", "", "", ""))
+	require.Error(t, rb.AddRule(true, ProtoAny, 0, 0, []string{}, "", "", "junk", "", ""))
+
+	// ICMP and ICMPv6 share one copy of each proto `any` rule
+	rb = NewRulesBuilder(l)
+	require.NoError(t, rb.AddRule(true, ProtoAny, PortAny, PortAny, []string{"default-group"}, "", "", "", "", ""))
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolICMPv6, PortAny, PortAny, []string{"nope"}, "", "", "", "", ""))
+	rules = rb.Build(nil, nil)
+	assert.Len(t, rules.In.protos[iputil.IPProtocolICMP][PortAny].Any.Groups, 2)
+	assert.Len(t, rules.In.protos[iputil.IPProtocolICMPv6][PortAny].Any.Groups, 2)
+
+	// No rules allow nothing
+	rules = NewRulesBuilder(l).Build(nil, nil)
+	for proto := range rules.In.protos {
+		assert.Nil(t, rules.In.protos[proto], "proto %d", proto)
+		assert.Nil(t, rules.Out.protos[proto], "proto %d", proto)
+	}
+}
+
+// TestRulesBuilder_sharedLocalCIDR ensures local cidrs shared between rules and ports are copied, not changed,
+// when another rule's local cidrs are added to them
+func TestRulesBuilder_sharedLocalCIDR(t *testing.T) {
+	vpnNetworks := []netip.Prefix{netip.MustParsePrefix("10.1.0.5/16")}
+	unsafeNetworks := []netip.Prefix{netip.MustParsePrefix("192.168.0.0/24")}
+	vpnAddr := netip.MustParseAddr("10.1.9.9")
+	unsafeAddr := netip.MustParseAddr("192.168.0.3")
+	otherAddr := netip.MustParseAddr("172.16.0.1")
+
+	rb := NewRulesBuilder(test.NewLogger())
+	// h1 allows the vpn networks by default on ports 1 and 2, and 172.16.0.0/12 as well on port 1
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolTCP, 1, 2, nil, "h1", "", "", "", ""))
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolTCP, 1, 1, nil, "h1", "", "172.16.0.0/12", "", ""))
+	// h2 allows 192.168.0.0/24 on ports 1 and 2, and the vpn networks by default as well on port 1
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolTCP, 1, 2, nil, "h2", "", "192.168.0.0/24", "", ""))
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolTCP, 1, 1, nil, "h2", "", "", "", ""))
+	// h3 only has the default
+	require.NoError(t, rb.AddRule(true, iputil.IPProtocolTCP, 3, 3, nil, "h3", "", "", "", ""))
+	rules := rb.Build(vpnNetworks, unsafeNetworks)
+
+	for _, tc := range []struct {
+		port int32
+		host string
+		addr netip.Addr
+		want bool
+	}{
+		{1, "h1", vpnAddr, true},
+		{1, "h1", otherAddr, true},
+		{1, "h1", unsafeAddr, false},
+		{2, "h1", vpnAddr, true},
+		{2, "h1", otherAddr, false},
+		{1, "h2", unsafeAddr, true},
+		{1, "h2", vpnAddr, true},
+		{1, "h2", otherAddr, false},
+		{2, "h2", unsafeAddr, true},
+		{2, "h2", vpnAddr, false},
+		{3, "h3", vpnAddr, true},
+		{3, "h3", otherAddr, false},
+		{3, "h3", unsafeAddr, false},
+	} {
+		lr := rules.In.protos[iputil.IPProtocolTCP][tc.port].Any.Hosts[tc.host]
+		assert.Equal(t, tc.want, lr.match(&Packet{LocalAddr: tc.addr}, nil), "port %d, %s, %s", tc.port, tc.host, tc.addr)
+	}
+}

firewall/table.go

@@ -56,7 +56,7 @@ type groupsRule struct {
 
 type localRules struct {
 	Any bool
-	// LocalCIDR is always set when Any isn't
+	// LocalCIDR is always set when Any isn't. It's shared with other localRules, so it's never changed.
 	LocalCIDR *bart.Lite
 }