test/patches/scapy-2.4/ipsec.patch

   1 diff --git a/scapy/layers/ipsec.py b/scapy/layers/ipsec.py
   2 index 69e7ae3b..99373466 100644
   3 --- a/scapy/layers/ipsec.py
   4 +++ b/scapy/layers/ipsec.py
   5 @@ -518,12 +517,16 @@ class AuthAlgo(object):
   6          else:
   7              return self.mac(key, self.digestmod(), default_backend())
   8
   9 -    def sign(self, pkt, key):
  10 +    def sign(self, pkt, key, trailer=None):
  11          """
  12          Sign an IPsec (ESP or AH) packet with this algo.
  13
  14          @param pkt:    a packet that contains a valid encrypted ESP or AH layer
  15          @param key:    the authentication key, a byte string
  16 +        @param trailer: additional data appended to the packet for ICV
  17 +                        calculation, but not trnasmitted with the packet.
  18 +                        For example, the high order bits of the exteneded
  19 +                        sequence number.
  20
  21          @return: the signed packet
  22          """
  23 @@ -539,11 +542,13 @@ class AuthAlgo(object):
  24          elif pkt.haslayer(AH):
  25              clone = zero_mutable_fields(pkt.copy(), sending=True)
  26              mac.update(raw(clone))
  27 +            if trailer:
  28 +                mac.update(trailer)
  29              pkt[AH].icv = mac.finalize()[:self.icv_size]
  30
  31          return pkt
  32
  33 -    def verify(self, pkt, key):
  34 +    def verify(self, pkt, key, trailer):
  35          """
  36          Check that the integrity check value (icv) of a packet is valid.
  37
  38 @@ -574,6 +579,8 @@ class AuthAlgo(object):
  39              clone = zero_mutable_fields(pkt.copy(), sending=False)
  40
  41          mac.update(raw(clone))
  42 +        if trailer:
  43 +            mac.update(trailer) # bytearray(4)) #raw(trailer))
  44          computed_icv = mac.finalize()[:self.icv_size]
  45
  46          # XXX: Cannot use mac.verify because the ICV can be truncated
  47 @@ -757,7 +764,8 @@ class SecurityAssociation(object):
  48      SUPPORTED_PROTOS = (IP, IPv6)
  49
  50      def __init__(self, proto, spi, seq_num=1, crypt_algo=None, crypt_key=None,
  51 -                 auth_algo=None, auth_key=None, tunnel_header=None, nat_t_header=None):
  52 +                 auth_algo=None, auth_key=None, tunnel_header=None, nat_t_header=None,
  53 +                 use_esn=False):
  54          """
  55          @param proto: the IPsec proto to use (ESP or AH)
  56          @param spi: the Security Parameters Index of this SA
  57 @@ -771,6 +779,7 @@ class SecurityAssociation(object):
  58                                to encapsulate the encrypted packets.
  59          @param nat_t_header: an instance of a UDP header that will be used
  60                               for NAT-Traversal.
  61 +        @param use_esn: Use Extended Sequence Numbers
  62          """
  63
  64          if proto not in (ESP, AH, ESP.name, AH.name):
  65 @@ -782,6 +791,7 @@ class SecurityAssociation(object):
  66
  67          self.spi = spi
  68          self.seq_num = seq_num
  69 +        self.use_esn = use_esn
  70
  71          if crypt_algo:
  72              if crypt_algo not in CRYPT_ALGOS:
  73 @@ -827,6 +837,17 @@ class SecurityAssociation(object):
  74              raise TypeError('packet spi=0x%x does not match the SA spi=0x%x' %
  75                              (pkt.spi, self.spi))
  76
  77 +    def build_seq_num(self, num):
  78 +        # only lower order bits are  transmitted
  79 +        # higher order bits are used in the ICV
  80 +        lower = num & 0xffffffff
  81 +        upper = num >> 32
  82 +
  83 +        if self.use_esn:
  84 +            return lower, struct.pack(">I", upper)
  85 +        else:
  86 +            return lower, None
  87 +
  88      def _encrypt_esp(self, pkt, seq_num=None, iv=None):
  89
  90          if iv is None:
  91 @@ -835,7 +856,8 @@ class SecurityAssociation(object):
  92              if len(iv) != self.crypt_algo.iv_size:
  93                  raise TypeError('iv length must be %s' % self.crypt_algo.iv_size)
  94
  95 -        esp = _ESPPlain(spi=self.spi, seq=seq_num or self.seq_num, iv=iv)
  96 +        low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
  97 +        esp = _ESPPlain(spi=self.spi, seq=low_seq_num, iv=iv)
  98
  99          if self.tunnel_header:
 100              tunnel = self.tunnel_header.copy()
 101 @@ -857,7 +879,7 @@ class SecurityAssociation(object):
 102          esp = self.crypt_algo.pad(esp)
 103          esp = self.crypt_algo.encrypt(self, esp, self.crypt_key)
 104
 105 -        self.auth_algo.sign(esp, self.auth_key)
 106 +        self.auth_algo.sign(esp, self.auth_key, high_seq_num)
 107
 108          if self.nat_t_header:
 109              nat_t_header = self.nat_t_header.copy()
 110 @@ -884,7 +906,8 @@ class SecurityAssociation(object):
 111
 112      def _encrypt_ah(self, pkt, seq_num=None):
 113
 114 -        ah = AH(spi=self.spi, seq=seq_num or self.seq_num,
 115 +        low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
 116 +        ah = AH(spi=self.spi, seq=low_seq_num,
 117                  icv = b"\x00" * self.auth_algo.icv_size)
 118
 119          if self.tunnel_header:
 120 @@ -924,7 +947,8 @@ class SecurityAssociation(object):
 121          else:
 122              ip_header.plen = len(ip_header.payload) + len(ah) + len(payload)
 123
 124 -        signed_pkt = self.auth_algo.sign(ip_header / ah / payload, self.auth_key)
 125 +        signed_pkt = self.auth_algo.sign(ip_header / ah / payload,
 126 +                                         self.auth_key, high_seq_num)
 127
 128          # sequence number must always change, unless specified by the user
 129          if seq_num is None:
 130 @@ -955,11 +979,12 @@ class SecurityAssociation(object):
 131
 132      def _decrypt_esp(self, pkt, verify=True):
 133
 134 +        low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
 135          encrypted = pkt[ESP]
 136
 137          if verify:
 138              self.check_spi(pkt)
 139 -            self.auth_algo.verify(encrypted, self.auth_key)
 140 +            self.auth_algo.verify(encrypted, self.auth_key, high_seq_num)
 141
 142          esp = self.crypt_algo.decrypt(self, encrypted, self.crypt_key,
 143                                        self.crypt_algo.icv_size or
 144 @@ -998,9 +1023,11 @@ class SecurityAssociation(object):
 145
 146      def _decrypt_ah(self, pkt, verify=True):
 147
 148 +        low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
 149 +
 150          if verify:
 151              self.check_spi(pkt)
 152 -            self.auth_algo.verify(pkt, self.auth_key)
 153 +            self.auth_algo.verify(pkt, self.auth_key, high_seq_num)
 154
 155          ah = pkt[AH]
 156          payload = ah.payload