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Code Issues Projects Releases Packages Wiki Activity Actions 7

refact: some refactoring to dhcp6 packet and spoofer

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This commit is contained in:
evilsocket 2018-01-13 15:55:56 +01:00
commit 87971a19e3
2 changed files with 66 additions and 61 deletions
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85
modules/dhcp6_spoof.go
View file

@ -76,31 +76,6 @@ func (s DHCP6Spoofer) Author() string {
return "Simone Margaritelli <evilsocket@protonmail.com>"
}
func (s *DHCP6Spoofer) encodeDomains() {
totLen := 0
for _, d := range s.Domains {
totLen += len(d)
}
if totLen > 0 {
s.RawDomains = make([]byte, totLen+1*len(s.Domains))
i := 0
for _, domain := range s.Domains {
lenDomain := len(domain)
plusOne := lenDomain + 1
s.RawDomains[i] = byte(lenDomain & 0xff)
k := 0
for j := i + 1; j < plusOne; j++ {
s.RawDomains[j] = domain[k]
k++
}
i += plusOne
}
}
}
func (s *DHCP6Spoofer) Configure() error {
var err error
var addr string
@ -117,7 +92,8 @@ func (s *DHCP6Spoofer) Configure() error {
if err, s.Domains = s.ListParam("dhcp6.spoof.domains"); err != nil {
return err
}
s.encodeDomains()
s.RawDomains = packets.DHCP6EncodeList(s.Domains)
if err, addr = s.StringParam("dhcp6.spoof.address"); err != nil {
return err
@ -134,6 +110,18 @@ func (s *DHCP6Spoofer) Configure() error {
return nil
}
func (s *DHCP6Spoofer) dhcp6For(what dhcp6.MessageType, to dhcp6.Packet) (err error, p dhcp6.Packet) {
err, p = packets.DHCP6For(what, to, s.DUIDRaw)
if err != nil {
return
}
p.Options.AddRaw(packets.DHCP6OptDNSServers, s.Session.Interface.IPv6)
p.Options.AddRaw(packets.DHCP6OptDNSDomains, s.RawDomains)
return nil, p
}
func (s *DHCP6Spoofer) dhcpAdvertise(pkt gopacket.Packet, solicit dhcp6.Packet, target net.HardwareAddr) {
pip6 := pkt.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
@ -144,6 +132,12 @@ func (s *DHCP6Spoofer) dhcpAdvertise(pkt gopacket.Packet, solicit dhcp6.Packet,
log.Info("[%s] Got DHCPv6 Solicit request from %s (%s), sending spoofed advertisement for %d domains.", core.Green("dhcp6"), core.Bold(fqdn), target, len(s.Domains))
err, adv := s.dhcp6For(dhcp6.MessageTypeAdvertise, solicit)
if err != nil {
log.Error("%s", err)
return
}
var solIANA dhcp6opts.IANA
if raw, found := solicit.Options[dhcp6.OptionIANA]; found == false || len(raw) < 1 {
@ -154,25 +148,6 @@ func (s *DHCP6Spoofer) dhcpAdvertise(pkt gopacket.Packet, solicit dhcp6.Packet,
return
}
adv := dhcp6.Packet{
MessageType: dhcp6.MessageTypeAdvertise,
TransactionID: solicit.TransactionID,
Options: make(dhcp6.Options),
}
adv.Options.AddRaw(packets.DHCP6OptDNSDomains, s.RawDomains)
adv.Options.AddRaw(packets.DHCP6OptDNSServers, s.Session.Interface.IPv6)
adv.Options.AddRaw(dhcp6.OptionServerID, s.DUIDRaw)
var rawCID []byte
if raw, found := solicit.Options[dhcp6.OptionClientID]; found == false || len(raw) < 1 {
log.Error("Unexpected DHCPv6 packet, could not find client id.")
return
} else {
rawCID = raw[0]
}
adv.Options.AddRaw(dhcp6.OptionClientID, rawCID)
var ip net.IP
if t, found := s.Session.Targets.Targets[target.String()]; found == true {
ip = t.IP
@ -251,24 +226,11 @@ func (s *DHCP6Spoofer) dhcpAdvertise(pkt gopacket.Packet, solicit dhcp6.Packet,
func (s *DHCP6Spoofer) dhcpReply(toType string, pkt gopacket.Packet, req dhcp6.Packet, target net.HardwareAddr) {
log.Debug("Sending spoofed DHCPv6 reply to %s after its %s packet.", core.Bold(target.String()), toType)
pip6 := pkt.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
reply := dhcp6.Packet{
MessageType: dhcp6.MessageTypeReply,
TransactionID: req.TransactionID,
Options: make(dhcp6.Options),
}
var rawCID []byte
if raw, found := req.Options[dhcp6.OptionClientID]; found == false || len(raw) < 1 {
log.Error("Unexpected DHCPv6 packet, could not find client id.")
err, reply := s.dhcp6For(dhcp6.MessageTypeReply, req)
if err != nil {
log.Error("%s", err)
return
} else {
rawCID = raw[0]
}
reply.Options.AddRaw(dhcp6.OptionClientID, rawCID)
reply.Options.AddRaw(dhcp6.OptionServerID, s.DUIDRaw)
reply.Options.AddRaw(packets.DHCP6OptDNSServers, s.Session.Interface.IPv6)
reply.Options.AddRaw(packets.DHCP6OptDNSDomains, s.RawDomains)
var reqIANA dhcp6opts.IANA
if raw, found := req.Options[dhcp6.OptionIANA]; found == false || len(raw) < 1 {
@ -302,6 +264,7 @@ func (s *DHCP6Spoofer) dhcpReply(toType string, pkt gopacket.Packet, req dhcp6.P
return
}
pip6 := pkt.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
eth := layers.Ethernet{
SrcMAC: s.Session.Interface.HW,
DstMAC: target,

42
packets/dhcp6.go
View file

@ -1,8 +1,50 @@
package packets
import (
"errors"
// TODO: refactor to use gopacket when gopacket folks
// will fix this > https://github.com/google/gopacket/issues/334
"github.com/mdlayher/dhcp6"
)
const DHCP6OptDNSServers = 23
const DHCP6OptDNSDomains = 24
const DHCP6OptClientFQDN = 39
// link-local
const IPv6Prefix = "fe80::"
var (
ErrNoCID = errors.New("Unexpected DHCPv6 packet, could not find client id.")
)
func DHCP6EncodeList(elements []string) (encoded []byte) {
encoded = make([]byte, 0)
for _, elem := range elements {
encoded = append(encoded, byte(len(elem)&0xff))
encoded = append(encoded, []byte(elem)...)
}
return
}
func DHCP6For(what dhcp6.MessageType, to dhcp6.Packet, duid []byte) (err error, p dhcp6.Packet) {
p = dhcp6.Packet{
MessageType: what,
TransactionID: to.TransactionID,
Options: make(dhcp6.Options),
}
var rawCID []byte
if raw, found := to.Options[dhcp6.OptionClientID]; found == false || len(raw) < 1 {
return ErrNoCID, p
} else {
rawCID = raw[0]
}
p.Options.AddRaw(dhcp6.OptionClientID, rawCID)
p.Options.AddRaw(dhcp6.OptionServerID, duid)
return nil, p
}