-
+
-
+
diff --git a/collectors/file_ingestor.go b/collectors/file_ingestor.go index f7f76044..5d48be8f 100644 --- a/collectors/file_ingestor.go +++ b/collectors/file_ingestor.go @@ -114,9 +114,9 @@ func (c *FileIngestor) ProcessPcap(filePath string) { packetSource.NoCopy = true // defrag ipv4 - go netutils.IPDefragger(fragIP4Chan, udpChan, tcpChan) + go netutils.IPDefragger(fragIP4Chan, udpChan, tcpChan, c.GetConfig().Collectors.FileIngestor.PcapDNSPort) // defrag ipv6 - go netutils.IPDefragger(fragIP6Chan, udpChan, tcpChan) + go netutils.IPDefragger(fragIP6Chan, udpChan, tcpChan, c.GetConfig().Collectors.FileIngestor.PcapDNSPort) // tcp assembly go netutils.TCPAssembler(tcpChan, dnsChan, c.GetConfig().Collectors.FileIngestor.PcapDNSPort) // udp processor diff --git a/collectors/sniffer_afpacket_linux.go b/collectors/sniffer_afpacket_linux.go index 3ba278a2..cd9bad85 100644 --- a/collectors/sniffer_afpacket_linux.go +++ b/collectors/sniffer_afpacket_linux.go @@ -102,9 +102,9 @@ func (c *AfpacketSniffer) Run() { netDecoder := &netutils.NetDecoder{} // defrag ipv4 - go netutils.IPDefragger(fragIP4Chan, udpChan, tcpChan) + go netutils.IPDefragger(fragIP4Chan, udpChan, tcpChan, c.GetConfig().Collectors.AfpacketLiveCapture.Port) // defrag ipv6 - go netutils.IPDefragger(fragIP6Chan, udpChan, tcpChan) + go netutils.IPDefragger(fragIP6Chan, udpChan, tcpChan, c.GetConfig().Collectors.AfpacketLiveCapture.Port) // tcp assembly go netutils.TCPAssembler(tcpChan, dnsChan, 0) // udp processor @@ -198,18 +198,24 @@ func (c *AfpacketSniffer) Run() { // ipv4 fragmented packet ? if packet.NetworkLayer().LayerType() == layers.LayerTypeIPv4 { + if !c.GetConfig().Collectors.AfpacketLiveCapture.FragmentSupport { + continue + } ip4 := packet.NetworkLayer().(*layers.IPv4) if ip4.Flags&layers.IPv4MoreFragments == 1 || ip4.FragOffset > 0 { - // fragIP4Chan <- packet + fragIP4Chan <- packet continue } } // ipv6 fragmented packet ? if packet.NetworkLayer().LayerType() == layers.LayerTypeIPv6 { + if !c.GetConfig().Collectors.AfpacketLiveCapture.FragmentSupport { + continue + } v6frag := packet.Layer(layers.LayerTypeIPv6Fragment) if v6frag != nil { - // fragIP6Chan <- packet + fragIP6Chan <- packet continue } } diff --git a/docs/collectors/collector_afpacket.md b/docs/collectors/collector_afpacket.md index 99910a02..6d009041 100644 --- a/docs/collectors/collector_afpacket.md +++ b/docs/collectors/collector_afpacket.md @@ -21,6 +21,9 @@ Options: * `device` (str) > Interface name to sniff. If value is empty, bind on all interfaces. +* `enable-fragment-support` (bool) + > Enable IP defrag support + * `chan-buffer-size` (int) > Specifies the maximum number of packets that can be buffered before dropping additional packets. @@ -31,5 +34,6 @@ Defaults: afpacket-sniffer: port: 53 device: wlp2s0 + enable-fragment-support: true chan-buffer-size: 65535 ``` diff --git a/netutils/bpf.go b/netutils/bpf.go index a132e275..c224c79d 100644 --- a/netutils/bpf.go +++ b/netutils/bpf.go @@ -23,34 +23,35 @@ func GetBpfFilter(port int) []bpf.Instruction { // Load eth.type (2 bytes at offset 12) and push-it in register A bpf.LoadAbsolute{Off: 12, Size: 2}, // if eth.type == IPv4 continue with the next instruction - bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x0800, SkipTrue: 0, SkipFalse: 10}, + bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x0800, SkipTrue: 0, SkipFalse: 11}, // Load ip.proto (1 byte at offset 23) and push-it in register A bpf.LoadAbsolute{Off: 23, Size: 1}, // ip.proto == UDP ? bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x11, SkipTrue: 1, SkipFalse: 0}, // ip.proto == TCP ? - bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x6, SkipTrue: 0, SkipFalse: 16}, - // load flags and fragment offset (2 bytes at offset 20) to ignore fragmented packet - bpf.LoadAbsolute{Off: 20, Size: 2}, + bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x6, SkipTrue: 0, SkipFalse: 17}, + // load flags and fragment offset (2 bytes at offset 20) // Only look at the last 13 bits of the data saved in regiter A // 0x1fff == 0001 1111 1111 1111 (fragment offset) - // If any of the data in fragment offset is true, ignore the packet + bpf.LoadAbsolute{Off: 20, Size: 2}, bpf.JumpIf{Cond: bpf.JumpBitsSet, Val: 0x1fff, SkipTrue: 14, SkipFalse: 0}, - // Load ip.length // Register X = ip header len * 4 bpf.LoadMemShift{Off: 14}, // Load source port in tcp or udp (2 bytes at offset x+14) bpf.LoadIndirect{Off: 14, Size: 2}, // source port equal to 53 ? - bpf.JumpIf{Cond: bpf.JumpEqual, Val: uint32(port), SkipTrue: 10, SkipFalse: 0}, + bpf.JumpIf{Cond: bpf.JumpEqual, Val: uint32(port), SkipTrue: 11, SkipFalse: 0}, // Load destination port in tcp or udp (2 bytes at offset x+16) bpf.LoadIndirect{Off: 16, Size: 2}, // destination port equal to 53 ? - bpf.JumpIf{Cond: bpf.JumpEqual, Val: uint32(port), SkipTrue: 8, SkipFalse: 9}, + bpf.JumpIf{Cond: bpf.JumpEqual, Val: uint32(port), SkipTrue: 9, SkipFalse: 10}, + // if eth.type == IPv6 continue with the next instruction - bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x86dd, SkipTrue: 0, SkipFalse: 8}, + bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x86dd, SkipTrue: 0, SkipFalse: 9}, // Load ipv6.nxt (2 bytes at offset 12) and push-it in register A bpf.LoadAbsolute{Off: 20, Size: 1}, + // fragment ? + bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x2c, SkipTrue: 6, SkipFalse: 0}, // ip.proto == UDP ? bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0x11, SkipTrue: 1, SkipFalse: 0}, // ip.proto == TCP ? @@ -63,6 +64,7 @@ func GetBpfFilter(port int) []bpf.Instruction { bpf.LoadAbsolute{Off: 56, Size: 2}, // destination port equal to 53 ? bpf.JumpIf{Cond: bpf.JumpEqual, Val: uint32(port), SkipTrue: 0, SkipFalse: 1}, + // Keep the packet and send up to 65k of the packet to userspace bpf.RetConstant{Val: 0xFFFF}, // Ignore packet diff --git a/netutils/ipdefrag.go b/netutils/ipdefrag.go index f1bd5e34..8080f369 100644 --- a/netutils/ipdefrag.go +++ b/netutils/ipdefrag.go @@ -56,11 +56,14 @@ func (f *fragments) insert(in gopacket.Packet) (gopacket.Packet, error) { var fragOffset uint16 - frag6 := packet.Layer(layers.LayerTypeIPv6Fragment).(*layers.IPv6Fragment) - ip4, _ := e.Value.(*layers.IPv4) - if frag6 != nil { - fragOffset = frag6.FragmentOffset * 8 - } else { + switch packet.NetworkLayer().LayerType() { + case layers.LayerTypeIPv6: + if frag6Layer := packet.Layer(layers.LayerTypeIPv6Fragment); frag6Layer != nil { + frag6 := frag6Layer.(*layers.IPv6Fragment) + fragOffset = frag6.FragmentOffset * 8 + } + case layers.LayerTypeIPv4: + ip4, _ := packet.Layer(layers.LayerTypeIPv4).(*layers.IPv4) fragOffset = ip4.FragOffset * 8 } diff --git a/netutils/ipdefrag_test.go b/netutils/ipdefrag_test.go index 665574c0..ea7b7e61 100644 --- a/netutils/ipdefrag_test.go +++ b/netutils/ipdefrag_test.go @@ -1,40 +1,101 @@ package netutils -// TODO -/* -func createIPv6FragmentPacketWithNilLayer() gopacket.Packet { - // IPv6 layer - ipLayer := &layers.IPv6{ - Version: 6, - NextHeader: layers.IPProtocolIPv6Fragment, // Next header is Fragmentation Header - HopLimit: 64, - SrcIP: net.ParseIP("2001:db8::1"), - DstIP: net.ParseIP("2001:db8::2"), - } - - // Create a packet with nil IPv6Fragment layer - builder := gopacket.NewSerializeBuffer() - ipLayer.SerializeTo(builder, gopacket.SerializeOptions{}) - // Set the IPv6 layer manually - packet := gopacket.NewPacket(builder.Bytes(), layers.LayerTypeIPv6, gopacket.Default) - // Remove IPv6Fragment layer - packet.Layer(layers.LayerTypeIPv6Fragment).(*layers.IPv6Fragment).Payload = nil - - return packet -} +import ( + "testing" + + "github.com/google/gopacket" + "github.com/google/gopacket/layers" +) +func TestIpDefrag_IPv4Fragment(t *testing.T) { + // fragmented packet, see the packet in testsdata/pcap/dnsdump_ip4_fragmented_query.pcap + frag1Bytes := []byte{0x58, 0x1d, 0xd8, 0x12, 0x84, 0x10, 0xb0, 0x35, 0x9f, 0xd4, 0x03, 0x91, 0x08, 0x00, + 0x45, 0x00, 0x00, 0x4c, 0x00, 0x01, 0x20, 0x00, 0x40, 0x11, 0xcb, 0x8f, 0x7f, 0x00, 0x00, 0x01, + 0x08, 0x08, 0x08, 0x08, 0x30, 0x39, 0x00, 0x35, 0x00, 0x5d, 0xf9, 0x10, 0xaa, 0xaa, 0x01, 0x00, + 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3f, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41} + frag1 := gopacket.NewPacket(frag1Bytes, layers.LayerTypeEthernet, gopacket.Default) + frag2Bytes := []byte{0x58, 0x1d, 0xd8, 0x12, 0x84, 0x10, 0xb0, 0x35, 0x9f, 0xd4, 0x03, 0x91, 0x08, 0x00, + 0x45, 0x00, 0x00, 0x39, 0x00, 0x01, 0x00, 0x07, 0x40, 0x11, 0xeb, 0x9b, 0x7f, 0x00, 0x00, 0x01, + 0x08, 0x08, 0x08, 0x08, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x03, 0x63, 0x6f, 0x6d, + 0x00, 0x00, 0x01, 0x00, 0x01} + frag2 := gopacket.NewPacket(frag2Bytes, layers.LayerTypeEthernet, gopacket.Default) -func TestIpDefrag_WithNilIPv6Fragment(t *testing.T) { defragger := NewIPDefragmenter() + _, err := defragger.DefragIP(frag1) + if err != nil { + t.Errorf("Unexpected error on the 1er defrag: %v", err) + } - // Create an IPv6 packet with nil IPv6Fragment layer - packet := createIPv6FragmentPacketWithNilLayer() + pkt, err := defragger.DefragIP(frag2) + if err != nil { + t.Errorf("Unexpected error on the 2nd defrag: %v", err) + } + if pkt.Metadata().Length != 113 { + t.Errorf("Invalid reassembled packet size: %v", err) + } +} - // This packet has a nil IPv6Fragment layer, which should trigger an error +func TestIpDefrag_IPv4FragmentWithRetransmission(t *testing.T) { + + // fragmented packet, see the packet in testsdata/pcap/dnsdump_ip4_fragmented_query.pcap + packetBytes := []byte{ + 0x58, 0x1d, 0xd8, 0x12, 0x84, 0x10, 0xb0, 0x35, 0x9f, 0xd4, 0x03, 0x91, 0x08, 0x00, 0x45, 0x00, + 0x00, 0x39, 0x00, 0x01, 0x00, 0x07, 0x40, 0x11, 0xeb, 0x9b, 0x7f, 0x00, 0x00, 0x01, 0x08, 0x08, + 0x08, 0x08, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x03, 0x63, + 0x6f, 0x6d, 0x00, 0x00, 0x01, 0x00, 0x01, + } + packet := gopacket.NewPacket(packetBytes, layers.LayerTypeEthernet, gopacket.Default) + + // This packet is just a fragment + defragger := NewIPDefragmenter() _, err := defragger.DefragIP(packet) - if err == nil { - t.Errorf("Expected error, got nil") + if err != nil { + t.Errorf("Unexpected error on the 1er defrag: %v", err) + } + + // Try to defrag the same packet + _, err = defragger.DefragIP(packet) + if err != nil { + t.Errorf("Unexpected error for the 2nd defrag: %v", err) + } +} + +func TestIpDefrag_IPv6Fragment(t *testing.T) { + // fragmented packet, see the packet in testsdata/pcap/dnsdump_ip4_fragmented_query.pcap + frag1Bytes := []byte{0x33, 0x33, 0x00, 0x00, 0x00, 0x01, 0xb0, 0x35, 0x9f, 0xd4, 0x03, 0x91, 0x86, 0xdd, 0x60, 0x00, + 0x00, 0x00, 0x00, 0x38, 0x2c, 0x40, 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x5b, 0x20, + 0xbf, 0xa1, 0x87, 0x8c, 0x3a, 0x68, 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x11, 0x00, 0x00, 0x01, 0xee, 0x8f, 0x5f, 0xf8, 0x30, 0x39, + 0x00, 0x35, 0x00, 0x61, 0x98, 0xc4, 0xaa, 0xaa, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x07, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x3f, 0x63, 0x6f, 0x6d, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41} + frag1 := gopacket.NewPacket(frag1Bytes, layers.LayerTypeEthernet, gopacket.Default) + frag2Bytes := []byte{0x33, 0x33, 0x00, 0x00, 0x00, 0x01, 0xb0, 0x35, 0x9f, 0xd4, 0x03, 0x91, 0x86, 0xdd, 0x60, 0x00, + 0x00, 0x00, 0x00, 0x39, 0x2c, 0x40, 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x5b, 0x20, + 0xbf, 0xa1, 0x87, 0x8c, 0x3a, 0x68, 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x11, 0x00, 0x00, 0x30, 0xee, 0x8f, 0x5f, 0xf8, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, + 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x00, 0x00, 0x01, 0x00, 0x01} + frag2 := gopacket.NewPacket(frag2Bytes, layers.LayerTypeEthernet, gopacket.Default) + + defragger := NewIPDefragmenter() + _, err := defragger.DefragIP(frag1) + if err != nil { + t.Errorf("Unexpected error on the 1er defrag: %v", err) + } + + pkt, err := defragger.DefragIP(frag2) + if err != nil { + t.Errorf("Unexpected error on the 2nd defrag: %v", err) + } + + if pkt.Metadata().Length != 137 { + t.Errorf("Invalid reassembled packet size: %v", err) } } -*/ diff --git a/netutils/packetproccesor.go b/netutils/packetproccesor.go index a582bf2e..dd6b1129 100644 --- a/netutils/packetproccesor.go +++ b/netutils/packetproccesor.go @@ -86,7 +86,7 @@ FLUSHALL: assembler.FlushAll() } -func IPDefragger(ipInput chan gopacket.Packet, udpOutput chan gopacket.Packet, tcpOutput chan gopacket.Packet) { +func IPDefragger(ipInput chan gopacket.Packet, udpOutput chan gopacket.Packet, tcpOutput chan gopacket.Packet, port int) { defragger := NewIPDefragmenter() for fragment := range ipInput { reassembled, err := defragger.DefragIP(fragment) @@ -96,10 +96,23 @@ func IPDefragger(ipInput chan gopacket.Packet, udpOutput chan gopacket.Packet, t if reassembled == nil { continue } + if reassembled.TransportLayer() != nil && reassembled.TransportLayer().LayerType() == layers.LayerTypeUDP { + // ignore packet regarding udp port + pkt := reassembled.TransportLayer().(*layers.UDP) + if pkt.DstPort != layers.UDPPort(port) && pkt.SrcPort != layers.UDPPort(port) { + continue + } + // valid reassembled packet udpOutput <- reassembled } if reassembled.TransportLayer() != nil && reassembled.TransportLayer().LayerType() == layers.LayerTypeTCP { + // ignore packet regarding udp port + pkt := reassembled.TransportLayer().(*layers.TCP) + if pkt.DstPort != layers.TCPPort(port) && pkt.SrcPort != layers.TCPPort(port) { + continue + } + // valid reassembled packet tcpOutput <- reassembled } } diff --git a/netutils/packetprocessor_test.go b/netutils/packetprocessor_test.go index e16445b5..628bbc7f 100644 --- a/netutils/packetprocessor_test.go +++ b/netutils/packetprocessor_test.go @@ -50,9 +50,9 @@ func Test_IpDefrag(t *testing.T) { outputChan := make(chan gopacket.Packet, 2) // defrag ipv4 - go IPDefragger(fragIP4Chan, outputChan, outputChan) + go IPDefragger(fragIP4Chan, outputChan, outputChan, 53) // defrag ipv6 - go IPDefragger(fragIP6Chan, outputChan, outputChan) + go IPDefragger(fragIP6Chan, outputChan, outputChan, 53) packetSource := gopacket.NewPacketSource(pcapHandler, pcapHandler.LinkType()) packetSource.DecodeOptions.Lazy = true diff --git a/pkgconfig/collectors.go b/pkgconfig/collectors.go index 13141c50..18b1a100 100644 --- a/pkgconfig/collectors.go +++ b/pkgconfig/collectors.go @@ -49,6 +49,7 @@ type ConfigCollectors struct { Port int `yaml:"port"` Device string `yaml:"device"` ChannelBufferSize int `yaml:"chan-buffer-size"` + FragmentSupport bool `yaml:"enable-defrag-ip"` } `yaml:"afpacket-sniffer"` XdpLiveCapture struct { Enable bool `yaml:"enable"` @@ -127,6 +128,7 @@ func (c *ConfigCollectors) SetDefault() { c.AfpacketLiveCapture.Port = 53 c.AfpacketLiveCapture.Device = "" c.AfpacketLiveCapture.ChannelBufferSize = 65535 + c.AfpacketLiveCapture.FragmentSupport = true c.PowerDNS.Enable = false c.PowerDNS.ListenIP = AnyIP diff --git a/testsdata/pcap/dnsdump_ip4_fragmented_query.pcap b/testsdata/pcap/dnsdump_ip4_fragmented_query.pcap new file mode 100644 index 00000000..65aa7eda Binary files /dev/null and b/testsdata/pcap/dnsdump_ip4_fragmented_query.pcap differ diff --git a/testsdata/pcap/dnsdump_ip6_fragmented_query.pcap b/testsdata/pcap/dnsdump_ip6_fragmented_query.pcap new file mode 100644 index 00000000..c922a275 Binary files /dev/null and b/testsdata/pcap/dnsdump_ip6_fragmented_query.pcap differ