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limit size of gopacket.SerializeBuffer #33338

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3 changes: 1 addition & 2 deletions pkg/networkpath/traceroute/icmp/tcp_parser.go
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Original file line number Diff line number Diff line change
Expand Up @@ -43,8 +43,7 @@ func NewICMPTCPParser() Parser {
icmpParser := &TCPParser{}
icmpParser.packetParser = gopacket.NewDecodingLayerParser(layers.LayerTypeICMPv4, &icmpParser.icmpLayer, &icmpParser.innerPayload)
icmpParser.innerPacketParser = gopacket.NewDecodingLayerParser(layers.LayerTypeIPv4, &icmpParser.innerIPLayer, &icmpParser.innerTCPLayer)
// TODO: can we ignore unsupported layers?
//icmpParser.packetParser.IgnoreUnsupported = true
icmpParser.packetParser.IgnoreUnsupported = true
return icmpParser
}

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1 change: 0 additions & 1 deletion pkg/networkpath/traceroute/icmp/udp_parser.go
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Expand Up @@ -42,7 +42,6 @@ func NewICMPUDPParser() Parser {
icmpParser := &UDPParser{}
icmpParser.packetParser = gopacket.NewDecodingLayerParser(layers.LayerTypeICMPv4, &icmpParser.icmpLayer)
icmpParser.innerPacketParser = gopacket.NewDecodingLayerParser(layers.LayerTypeIPv4, &icmpParser.innerIPLayer, &icmpParser.innerUDPLayer)
// TODO: can we ignore unsupported layers?
icmpParser.packetParser.IgnoreUnsupported = true
return icmpParser
}
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4 changes: 3 additions & 1 deletion pkg/networkpath/traceroute/tcp/tcpv4.go
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Expand Up @@ -35,7 +35,7 @@ type (

// NewTCPv4 initializes a new TCPv4 traceroute instance
func NewTCPv4(target net.IP, targetPort uint16, numPaths uint16, minTTL uint8, maxTTL uint8, delay time.Duration, timeout time.Duration) *TCPv4 {
buffer := gopacket.NewSerializeBuffer()
buffer := gopacket.NewSerializeBufferExpectedSize(40, 0)

return &TCPv4{
Target: target,
Expand Down Expand Up @@ -67,6 +67,8 @@ func (t *TCPv4) createRawTCPSyn(seqNum uint32, ttl int) (*ipv4.Header, []byte, e
}

func (t *TCPv4) createRawTCPSynBuffer(seqNum uint32, ttl int) (*ipv4.Header, []byte, int, error) {
// if this function is modified in a way that changes the size,
// update the NewSerializeBufferExpectedSize call in NewTCPv4
ipLayer := &layers.IPv4{
Version: 4,
Length: 20,
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6 changes: 5 additions & 1 deletion pkg/networkpath/traceroute/udp/udpv4.go
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Expand Up @@ -12,6 +12,7 @@ import (
"time"

"github.com/DataDog/datadog-agent/pkg/networkpath/traceroute/icmp"
"github.com/DataDog/datadog-agent/pkg/util/log"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"golang.org/x/net/ipv4"
Expand All @@ -38,7 +39,7 @@ type (
// NewUDPv4 initializes a new UDPv4 traceroute instance
func NewUDPv4(target net.IP, targetPort uint16, numPaths uint16, minTTL uint8, maxTTL uint8, delay time.Duration, timeout time.Duration) *UDPv4 {
icmpParser := icmp.NewICMPUDPParser()
buffer := gopacket.NewSerializeBuffer()
buffer := gopacket.NewSerializeBufferExpectedSize(36, 0)

return &UDPv4{
Target: target,
Expand Down Expand Up @@ -66,6 +67,8 @@ func (u *UDPv4) Close() error {
//
// the nolint:unused is necessary because we don't yet use this outside the Windows implementation
func (u *UDPv4) createRawUDPBuffer(sourceIP net.IP, sourcePort uint16, destIP net.IP, destPort uint16, ttl int) (*ipv4.Header, []byte, uint16, int, error) { //nolint:unused
// if this function is modified in a way that changes the size,
// update the NewSerializeBufferExpectedSize call in NewUDPv4
ipLayer := &layers.IPv4{
Version: 4,
Length: 20,
Expand Down Expand Up @@ -108,6 +111,7 @@ func (u *UDPv4) createRawUDPBuffer(sourceIP net.IP, sourcePort uint16, destIP ne
return nil, nil, 0, 0, fmt.Errorf("failed to serialize packet: %w", err)
}
packet := u.buffer.Bytes()
log.Errorf("UDP Packet Length: %d", len(packet))

var ipHdr ipv4.Header
if err := ipHdr.Parse(packet[:20]); err != nil {
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