test/patches/scapy-2.4/ipsec.patch

   1 diff --git a/scapy/layers/ipsec.py b/scapy/layers/ipsec.py
   2 index 69e7ae3b..b35da2b1 100644
   3 --- a/scapy/layers/ipsec.py
   4 +++ b/scapy/layers/ipsec.py
   5 @@ -518,12 +518,16 @@ 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 @@ -534,16 +538,20 @@ class AuthAlgo(object):
  24
  25          if pkt.haslayer(ESP):
  26              mac.update(raw(pkt[ESP]))
  27 +            if trailer:
  28 +                mac.update(trailer)
  29              pkt[ESP].data += mac.finalize()[:self.icv_size]
  30
  31          elif pkt.haslayer(AH):
  32              clone = zero_mutable_fields(pkt.copy(), sending=True)
  33              mac.update(raw(clone))
  34 +            if trailer:
  35 +                mac.update(trailer)
  36              pkt[AH].icv = mac.finalize()[:self.icv_size]
  37
  38          return pkt
  39
  40 -    def verify(self, pkt, key):
  41 +    def verify(self, pkt, key, trailer):
  42          """
  43          Check that the integrity check value (icv) of a packet is valid.
  44
  45 @@ -574,6 +582,8 @@ class AuthAlgo(object):
  46              clone = zero_mutable_fields(pkt.copy(), sending=False)
  47
  48          mac.update(raw(clone))
  49 +        if trailer:
  50 +            mac.update(trailer) # bytearray(4)) #raw(trailer))
  51          computed_icv = mac.finalize()[:self.icv_size]
  52
  53          # XXX: Cannot use mac.verify because the ICV can be truncated
  54 @@ -757,7 +767,8 @@ class SecurityAssociation(object):
  55      SUPPORTED_PROTOS = (IP, IPv6)
  56
  57      def __init__(self, proto, spi, seq_num=1, crypt_algo=None, crypt_key=None,
  58 -                 auth_algo=None, auth_key=None, tunnel_header=None, nat_t_header=None):
  59 +                 auth_algo=None, auth_key=None, tunnel_header=None, nat_t_header=None,
  60 +                 use_esn=False):
  61          """
  62          @param proto: the IPsec proto to use (ESP or AH)
  63          @param spi: the Security Parameters Index of this SA
  64 @@ -771,6 +782,7 @@ class SecurityAssociation(object):
  65                                to encapsulate the encrypted packets.
  66          @param nat_t_header: an instance of a UDP header that will be used
  67                               for NAT-Traversal.
  68 +        @param use_esn: Use Extended Sequence Numbers
  69          """
  70
  71          if proto not in (ESP, AH, ESP.name, AH.name):
  72 @@ -782,6 +794,7 @@ class SecurityAssociation(object):
  73
  74          self.spi = spi
  75          self.seq_num = seq_num
  76 +        self.use_esn = use_esn
  77
  78          if crypt_algo:
  79              if crypt_algo not in CRYPT_ALGOS:
  80 @@ -827,6 +840,17 @@ class SecurityAssociation(object):
  81              raise TypeError('packet spi=0x%x does not match the SA spi=0x%x' %
  82                              (pkt.spi, self.spi))
  83
  84 +    def build_seq_num(self, num):
  85 +        # only lower order bits are  transmitted
  86 +        # higher order bits are used in the ICV
  87 +        lower = num & 0xffffffff
  88 +        upper = num >> 32
  89 +
  90 +        if self.use_esn:
  91 +            return lower, struct.pack(">I", upper)
  92 +        else:
  93 +            return lower, None
  94 +
  95      def _encrypt_esp(self, pkt, seq_num=None, iv=None):
  96
  97          if iv is None:
  98 @@ -835,7 +859,8 @@ class SecurityAssociation(object):
  99              if len(iv) != self.crypt_algo.iv_size:
 100                  raise TypeError('iv length must be %s' % self.crypt_algo.iv_size)
 101
 102 -        esp = _ESPPlain(spi=self.spi, seq=seq_num or self.seq_num, iv=iv)
 103 +        low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
 104 +        esp = _ESPPlain(spi=self.spi, seq=low_seq_num, iv=iv)
 105
 106          if self.tunnel_header:
 107              tunnel = self.tunnel_header.copy()
 108 @@ -857,7 +882,7 @@ class SecurityAssociation(object):
 109          esp = self.crypt_algo.pad(esp)
 110          esp = self.crypt_algo.encrypt(self, esp, self.crypt_key)
 111
 112 -        self.auth_algo.sign(esp, self.auth_key)
 113 +        self.auth_algo.sign(esp, self.auth_key, high_seq_num)
 114
 115          if self.nat_t_header:
 116              nat_t_header = self.nat_t_header.copy()
 117 @@ -884,7 +909,8 @@ class SecurityAssociation(object):
 118
 119      def _encrypt_ah(self, pkt, seq_num=None):
 120
 121 -        ah = AH(spi=self.spi, seq=seq_num or self.seq_num,
 122 +        low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
 123 +        ah = AH(spi=self.spi, seq=low_seq_num,
 124                  icv = b"\x00" * self.auth_algo.icv_size)
 125
 126          if self.tunnel_header:
 127 @@ -924,7 +950,8 @@ class SecurityAssociation(object):
 128          else:
 129              ip_header.plen = len(ip_header.payload) + len(ah) + len(payload)
 130
 131 -        signed_pkt = self.auth_algo.sign(ip_header / ah / payload, self.auth_key)
 132 +        signed_pkt = self.auth_algo.sign(ip_header / ah / payload,
 133 +                                         self.auth_key, high_seq_num)
 134
 135          # sequence number must always change, unless specified by the user
 136          if seq_num is None:
 137 @@ -955,11 +982,12 @@ class SecurityAssociation(object):
 138
 139      def _decrypt_esp(self, pkt, verify=True):
 140
 141 +        low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
 142          encrypted = pkt[ESP]
 143
 144          if verify:
 145              self.check_spi(pkt)
 146 -            self.auth_algo.verify(encrypted, self.auth_key)
 147 +            self.auth_algo.verify(encrypted, self.auth_key, high_seq_num)
 148
 149          esp = self.crypt_algo.decrypt(self, encrypted, self.crypt_key,
 150                                        self.crypt_algo.icv_size or
 151 @@ -998,9 +1026,11 @@ class SecurityAssociation(object):
 152
 153      def _decrypt_ah(self, pkt, verify=True):
 154
 155 +        low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
 156 +
 157          if verify:
 158              self.check_spi(pkt)
 159 -            self.auth_algo.verify(pkt, self.auth_key)
 160 +            self.auth_algo.verify(pkt, self.auth_key, high_seq_num)
 161
 162          ah = pkt[AH]
 163          payload = ah.payload