Stop audit record serialization from crashing on absent nested messages

io/audit_record_nil_test.go

@@ -0,0 +1,90 @@
+package io
+
+import (
+	"runtime/debug"
+	"testing"
+
+	"github.com/dreadl0ck/netcap/encoder"
+	"github.com/dreadl0ck/netcap/types"
+)
+
+// TestAuditRecordSerializationOnZeroValue guards against nil dereferences in the
+// serialization helpers. Optional nested messages are nil whenever the protocol
+// did not carry them, which is the common case rather than an edge case: BFD
+// packets without authentication used to segfault the whole capture here.
+func TestAuditRecordSerializationOnZeroValue(t *testing.T) {
+	// Encode() dereferences the encoder config, which the --encode path installs.
+	encoder.SetConfig(&encoder.Config{ZScore: true})
+
+	covered := 0
+
+	for num, name := range types.Type_name {
+		typ := types.Type(num)
+		if typ == types.Type_NC_Header {
+			continue
+		}
+
+		record, ok := InitRecord(typ).(types.AuditRecord)
+		if !ok {
+			// Not every enum entry has a registered audit record implementation.
+			continue
+		}
+		covered++
+
+		t.Run(name, func(t *testing.T) {
+			// Recover so one broken type does not hide the rest.
+			defer func() {
+				if r := recover(); r != nil {
+					t.Fatalf("panic: %v\n%s", r, debug.Stack())
+				}
+			}()
+
+			header := record.CSVHeader()
+			values := record.CSVRecord()
+			if len(header) != len(values) {
+				t.Errorf("CSVHeader has %d fields, CSVRecord has %d", len(header), len(values))
+			}
+			if encoded := record.Encode(); encoded == nil && len(header) > 0 {
+				t.Error("Encode returned nil")
+			}
+			if _, err := record.JSON(); err != nil {
+				t.Errorf("JSON: %v", err)
+			}
+			record.Time()
+			record.Src()
+			record.Dst()
+			record.NetcapType()
+			record.SetPacketContext(&types.PacketContext{})
+
+			// Prometheus panics when the label cardinality of the vector does
+			// not match the values Inc() derives from CSVRecord. Calling it
+			// twice is safe: WithLabelValues returns the same child.
+			record.Inc()
+			record.Inc()
+		})
+	}
+
+	if covered < 50 {
+		t.Fatalf("only %d audit record types covered, expected the full set", covered)
+	}
+}
+
+// TestBFDNilAuthHeader pins the specific regression: BFD without authentication.
+func TestBFDNilAuthHeader(t *testing.T) {
+	bfd := &types.BFD{Timestamp: 1, AuthPresent: false}
+	if bfd.AuthHeader != nil {
+		t.Fatal("expected a nil AuthHeader")
+	}
+	if got := bfd.CSVRecord(); got[len(got)-1] != "" {
+		t.Errorf("AuthHeader field = %q, want empty", got[len(got)-1])
+	}
+
+	withAuth := &types.BFD{
+		Timestamp:   1,
+		AuthPresent: true,
+		AuthHeader:  &types.BFDAuthHeader{AuthType: 2, KeyID: 3, SequenceNumber: 4, Data: []byte{0xab}},
+	}
+	if got := withAuth.CSVRecord(); got[len(got)-1] == "" {
+		t.Error("populated AuthHeader must still be serialized")
+	}
+}

types/bfd.go

@@ -102,7 +102,12 @@ func (b *BFD) Time() int64 {
 	return b.Timestamp
 }
 
-func (bah BFDAuthHeader) getString() string {
+func (bah *BFDAuthHeader) getString() string {
+	// BFD packets without authentication carry no auth header.
+	if bah == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)

types/cisco_discovery.go

@@ -70,7 +70,11 @@ func (cd *CiscoDiscovery) Time() int64 {
 	return cd.Timestamp
 }
 
-func (v CiscoDiscoveryValue) toString() string {
+func (v *CiscoDiscoveryValue) toString() string {
+	if v == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)

types/cisco_discovery_info.go

@@ -145,6 +145,10 @@ func (a *CiscoDiscoveryInfo) Time() int64 {
 }
 
 func (c *CDPHello) toString() string {
+	if c == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)
@@ -177,6 +181,10 @@ func (c *CDPHello) toString() string {
 }
 
 func (c *CDPCapabilities) toString() string {
+	if c == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)
@@ -204,6 +212,10 @@ func (c *CDPCapabilities) toString() string {
 }
 
 func (i *IPNet) toString() string {
+	if i == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)
@@ -216,6 +228,10 @@ func (i *IPNet) toString() string {
 }
 
 func (c *CDPVLANDialogue) toString() string {
+	if c == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)
@@ -228,6 +244,10 @@ func (c *CDPVLANDialogue) toString() string {
 }
 
 func (c *CDPPowerDialogue) toString() string {
+	if c == nil {
+		return ""
+	}
+
 	vals := make([]string, 0, len(c.Values))
 
 	for _, v := range c.Values {
@@ -248,6 +268,10 @@ func (c *CDPPowerDialogue) toString() string {
 }
 
 func (c *CDPSparePairPoE) toString() string {
+	if c == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)
@@ -264,6 +288,10 @@ func (c *CDPSparePairPoE) toString() string {
 }
 
 func (c *CDPEnergyWise) toString() string {
+	if c == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)
@@ -304,6 +332,10 @@ func (c *CDPEnergyWise) toString() string {
 }
 
 func (c *CDPLocation) toString() string {
+	if c == nil {
+		return ""
+	}
+
 	var b strings.Builder
 
 	b.WriteString(StructureBegin)

types/dhcp4.go

@@ -110,7 +110,11 @@ func (d *DHCPv4) Time() int64 {
 	return d.Timestamp
 }
 
-func (d DHCPOption) toString() string {
+func (d *DHCPOption) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(d.Type))

types/dhcp6.go

@@ -83,7 +83,11 @@ func (d *DHCPv6) Time() int64 {
 	return d.Timestamp
 }
 
-func (d DHCPv6Option) toString() string {
+func (d *DHCPv6Option) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(d.Code))

types/dns.go

@@ -133,6 +133,10 @@ func (d *DNS) Time() int64 {
 }
 
 func (q *DNSQuestion) toString() string {
+	if q == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(q.Name)
@@ -145,6 +149,10 @@ func (q *DNSQuestion) toString() string {
 }
 
 func (q *DNSResourceRecord) toString() string {
+	if q == nil {
+		return ""
+	}
+
 	txts := make([]string, 0, len(q.TXTs))
 	for _, t := range q.TXTs {
 		txts = append(txts, string(t))
@@ -188,6 +196,10 @@ func (q *DNSResourceRecord) toString() string {
 }
 
 func (q *DNSSOA) toString() string {
+	if q == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(string(q.MName))
@@ -208,6 +220,10 @@ func (q *DNSSOA) toString() string {
 }
 
 func (q *DNSSRV) toString() string {
+	if q == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(q.Priority))
@@ -222,6 +238,10 @@ func (q *DNSSRV) toString() string {
 }
 
 func (q *DNSMX) toString() string {
+	if q == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(q.Preference))

types/dot11.go

@@ -89,7 +89,11 @@ func (d *Dot11) Time() int64 {
 	return d.Timestamp
 }
 
-func (d Dot11QOS) toString() string {
+func (d *Dot11QOS) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(d.TID))
@@ -103,7 +107,11 @@ func (d Dot11QOS) toString() string {
 	return b.String()
 }
 
-func (d Dot11HTControl) toString() string {
+func (d *Dot11HTControl) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(strconv.FormatBool(d.ACConstraint))
@@ -118,6 +126,10 @@ func (d Dot11HTControl) toString() string {
 }
 
 func (d *Dot11HTControlVHT) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(strconv.FormatBool(d.MRQ))
@@ -144,6 +156,10 @@ func (d *Dot11HTControlVHT) toString() string {
 }
 
 func (d *Dot11HTControlMFB) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(d.NumSTS))
@@ -158,6 +174,10 @@ func (d *Dot11HTControlMFB) toString() string {
 }
 
 func (d *Dot11HTControlHT) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(d.LinkAdapationControl.toString())
@@ -176,6 +196,10 @@ func (d *Dot11HTControlHT) toString() string {
 }
 
 func (d *Dot11LinkAdapationControl) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(strconv.FormatBool(d.TRQ))
@@ -194,6 +218,10 @@ func (d *Dot11LinkAdapationControl) toString() string {
 }
 
 func (d *Dot11ASEL) toString() string {
+	if d == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(d.Command))

types/geneve.go

@@ -77,7 +77,11 @@ func (i *Geneve) Time() int64 {
 	return i.Timestamp
 }
 
-func (i GeneveOption) toString() string {
+func (i *GeneveOption) toString() string {
+	if i == nil {
+		return ""
+	}
+
 	var b strings.Builder
 	b.WriteString(StructureBegin)
 	b.WriteString(formatInt32(i.Class))

types/gre.go

@@ -65,8 +65,6 @@ var fieldsGRE = []string{
 	fieldRouting,           // *GRERouting
 	fieldSrcIP,
 	fieldDstIP,
-	fieldSrcPort,
-	fieldDstPort,
 }
 
 // CSVHeader returns the CSV header for the audit record.