test/patches/scapy-2.4/ipsec.patch

   1 diff --git a/scapy/layers/ipsec.py b/scapy/layers/ipsec.py
   2 index 69e7ae3b..0c69ba1a 100644
   3 --- a/scapy/layers/ipsec.py
   4 +++ b/scapy/layers/ipsec.py
   5 @@ -344,7 +344,8 @@ class CryptAlgo(object):
   6              encryptor = cipher.encryptor()
   7
   8              if self.is_aead:
   9 -                aad = struct.pack('!LL', esp.spi, esp.seq)
  10 +                aad = struct.pack('!LQ' if sa.use_esn else '!LL',
  11 +                                  esp.spi, esp.seq)
  12                  encryptor.authenticate_additional_data(aad)
  13                  data = encryptor.update(data) + encryptor.finalize()
  14                  data += encryptor.tag[:self.icv_size]
  15 @@ -381,9 +382,9 @@ class CryptAlgo(object):
  16              if self.is_aead:
  17                  # Tag value check is done during the finalize method
  18                  decryptor.authenticate_additional_data(
  19 -                    struct.pack('!LL', esp.spi, esp.seq)
  20 +                    struct.pack('!LQ' if sa.use_esn else '!LL',
  21 +                                esp.spi, esp.seq)
  22                  )
  23 -
  24              try:
  25                  data = decryptor.update(data) + decryptor.finalize()
  26              except InvalidTag as err:
  27 @@ -518,12 +519,16 @@ class AuthAlgo(object):
  28          else:
  29              return self.mac(key, self.digestmod(), default_backend())
  30
  31 -    def sign(self, pkt, key):
  32 +    def sign(self, pkt, key, trailer=None):
  33          """
  34          Sign an IPsec (ESP or AH) packet with this algo.
  35
  36          @param pkt:    a packet that contains a valid encrypted ESP or AH layer
  37          @param key:    the authentication key, a byte string
  38 +        @param trailer: additional data appended to the packet for ICV
  39 +                        calculation, but not trnasmitted with the packet.
  40 +                        For example, the high order bits of the exteneded
  41 +                        sequence number.
  42
  43          @return: the signed packet
  44          """
  45 @@ -534,16 +539,20 @@ class AuthAlgo(object):
  46
  47          if pkt.haslayer(ESP):
  48              mac.update(raw(pkt[ESP]))
  49 +            if trailer:
  50 +                mac.update(trailer)
  51              pkt[ESP].data += mac.finalize()[:self.icv_size]
  52
  53          elif pkt.haslayer(AH):
  54              clone = zero_mutable_fields(pkt.copy(), sending=True)
  55              mac.update(raw(clone))
  56 +            if trailer:
  57 +                mac.update(trailer)
  58              pkt[AH].icv = mac.finalize()[:self.icv_size]
  59
  60          return pkt
  61
  62 -    def verify(self, pkt, key):
  63 +    def verify(self, pkt, key, trailer):
  64          """
  65          Check that the integrity check value (icv) of a packet is valid.
  66
  67 @@ -574,6 +583,8 @@ class AuthAlgo(object):
  68              clone = zero_mutable_fields(pkt.copy(), sending=False)
  69
  70          mac.update(raw(clone))
  71 +        if trailer:
  72 +            mac.update(trailer) # bytearray(4)) #raw(trailer))
  73          computed_icv = mac.finalize()[:self.icv_size]
  74
  75          # XXX: Cannot use mac.verify because the ICV can be truncated
  76 @@ -757,7 +768,8 @@ class SecurityAssociation(object):
  77      SUPPORTED_PROTOS = (IP, IPv6)
  78
  79      def __init__(self, proto, spi, seq_num=1, crypt_algo=None, crypt_key=None,
  80 -                 auth_algo=None, auth_key=None, tunnel_header=None, nat_t_header=None):
  81 +                 auth_algo=None, auth_key=None, tunnel_header=None, nat_t_header=None,
  82 +                 use_esn=False):
  83          """
  84          @param proto: the IPsec proto to use (ESP or AH)
  85          @param spi: the Security Parameters Index of this SA
  86 @@ -771,6 +783,7 @@ class SecurityAssociation(object):
  87                                to encapsulate the encrypted packets.
  88          @param nat_t_header: an instance of a UDP header that will be used
  89                               for NAT-Traversal.
  90 +        @param use_esn: Use Extended Sequence Numbers
  91          """
  92
  93          if proto not in (ESP, AH, ESP.name, AH.name):
  94 @@ -782,6 +795,7 @@ class SecurityAssociation(object):
  95
  96          self.spi = spi
  97          self.seq_num = seq_num
  98 +        self.use_esn = use_esn
  99
 100          if crypt_algo:
 101              if crypt_algo not in CRYPT_ALGOS:
 102 @@ -827,6 +841,17 @@ class SecurityAssociation(object):
 103              raise TypeError('packet spi=0x%x does not match the SA spi=0x%x' %
 104                              (pkt.spi, self.spi))
 105
 106 +    def build_seq_num(self, num):
 107 +        # only lower order bits are  transmitted
 108 +        # higher order bits are used in the ICV
 109 +        lower = num & 0xffffffff
 110 +        upper = num >> 32
 111 +
 112 +        if self.use_esn:
 113 +            return lower, struct.pack("!I", upper)
 114 +        else:
 115 +            return lower, None
 116 +
 117      def _encrypt_esp(self, pkt, seq_num=None, iv=None):
 118
 119          if iv is None:
 120 @@ -835,7 +860,8 @@ class SecurityAssociation(object):
 121              if len(iv) != self.crypt_algo.iv_size:
 122                  raise TypeError('iv length must be %s' % self.crypt_algo.iv_size)
 123
 124 -        esp = _ESPPlain(spi=self.spi, seq=seq_num or self.seq_num, iv=iv)
 125 +        low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
 126 +        esp = _ESPPlain(spi=self.spi, seq=low_seq_num, iv=iv)
 127
 128          if self.tunnel_header:
 129              tunnel = self.tunnel_header.copy()
 130 @@ -857,7 +883,7 @@ class SecurityAssociation(object):
 131          esp = self.crypt_algo.pad(esp)
 132          esp = self.crypt_algo.encrypt(self, esp, self.crypt_key)
 133
 134 -        self.auth_algo.sign(esp, self.auth_key)
 135 +        self.auth_algo.sign(esp, self.auth_key, high_seq_num)
 136
 137          if self.nat_t_header:
 138              nat_t_header = self.nat_t_header.copy()
 139 @@ -884,7 +910,8 @@ class SecurityAssociation(object):
 140
 141      def _encrypt_ah(self, pkt, seq_num=None):
 142
 143 -        ah = AH(spi=self.spi, seq=seq_num or self.seq_num,
 144 +        low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
 145 +        ah = AH(spi=self.spi, seq=low_seq_num,
 146                  icv = b"\x00" * self.auth_algo.icv_size)
 147
 148          if self.tunnel_header:
 149 @@ -924,7 +951,8 @@ class SecurityAssociation(object):
 150          else:
 151              ip_header.plen = len(ip_header.payload) + len(ah) + len(payload)
 152
 153 -        signed_pkt = self.auth_algo.sign(ip_header / ah / payload, self.auth_key)
 154 +        signed_pkt = self.auth_algo.sign(ip_header / ah / payload,
 155 +                                         self.auth_key, high_seq_num)
 156
 157          # sequence number must always change, unless specified by the user
 158          if seq_num is None:
 159 @@ -955,11 +983,12 @@ class SecurityAssociation(object):
 160
 161      def _decrypt_esp(self, pkt, verify=True):
 162
 163 +        low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
 164          encrypted = pkt[ESP]
 165
 166          if verify:
 167              self.check_spi(pkt)
 168 -            self.auth_algo.verify(encrypted, self.auth_key)
 169 +            self.auth_algo.verify(encrypted, self.auth_key, high_seq_num)
 170
 171          esp = self.crypt_algo.decrypt(self, encrypted, self.crypt_key,
 172                                        self.crypt_algo.icv_size or
 173 @@ -998,9 +1027,11 @@ class SecurityAssociation(object):
 174
 175      def _decrypt_ah(self, pkt, verify=True):
 176
 177 +        low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
 178 +
 179          if verify:
 180              self.check_spi(pkt)
 181 -            self.auth_algo.verify(pkt, self.auth_key)
 182 +            self.auth_algo.verify(pkt, self.auth_key, high_seq_num)
 183
 184          ah = pkt[AH]
 185          payload = ah.payload