ipsec: GCM, Anti-replay and ESN fixess

Type: fix

Several Fixes:
 1 - Anti-replay did not work with GCM becuase it overwrote the sequence
number in the ESP header. To fix i added the seq num to the per-packet
data so it is preserved
 2 - The high sequence number was not byte swapped during ESP encrypt.
 3 - openssl engine was the only one to return FAIL_DECRYPT for bad GCM
the others return BAD_HMAC. removed the former
 4 - improved tracing to show the low and high seq numbers
 5 - documented the anti-replay window checks
 6 - fixed scapy patch for ESN support for GCM
 7 - tests for anti-reply (w/ and w/o ESN) for each crypto algo

Change-Id: Id65d96b6d1d4dd821b2ab557e87468fff6d70e5b
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 29 insertions, 23 deletions

diff --git a/test/patches/scapy-2.4/ipsec.patch b/test/patches/scapy-2.4/ipsec.patch
index 731fe3ccc25..083b0b94961 100644
--- a/test/patches/scapy-2.4/ipsec.patch
+++ b/test/patches/scapy-2.4/ipsec.patch
@@ -1,30 +1,30 @@
 diff --git a/scapy/layers/ipsec.py b/scapy/layers/ipsec.py
-index 69e7ae3b..0c69ba1a 100644
+index 69e7ae3b..3a1724b2 100644
 --- a/scapy/layers/ipsec.py
 +++ b/scapy/layers/ipsec.py
-@@ -344,7 +344,8 @@ class CryptAlgo(object):
+@@ -344,8 +344,7 @@ class CryptAlgo(object):
              encryptor = cipher.encryptor()
  
              if self.is_aead:
 -                aad = struct.pack('!LL', esp.spi, esp.seq)
-+                aad = struct.pack('!LQ' if sa.use_esn else '!LL',
-+                                  esp.spi, esp.seq)
-                 encryptor.authenticate_additional_data(aad)
+-                encryptor.authenticate_additional_data(aad)
++                encryptor.authenticate_additional_data(sa.build_aead(esp))
                  data = encryptor.update(data) + encryptor.finalize()
                  data += encryptor.tag[:self.icv_size]
-@@ -381,9 +382,9 @@ class CryptAlgo(object):
+             else:
+@@ -380,10 +379,7 @@ class CryptAlgo(object):
+ 
              if self.is_aead:
                  # Tag value check is done during the finalize method
-                 decryptor.authenticate_additional_data(
+-                decryptor.authenticate_additional_data(
 -                    struct.pack('!LL', esp.spi, esp.seq)
-+                    struct.pack('!LQ' if sa.use_esn else '!LL',
-+                                esp.spi, esp.seq)
-                 )
+-                )
 -
++                decryptor.authenticate_additional_data(sa.build_aead(esp))
              try:
                  data = decryptor.update(data) + decryptor.finalize()
              except InvalidTag as err:
-@@ -518,12 +519,16 @@ class AuthAlgo(object):
+@@ -518,12 +514,16 @@ class AuthAlgo(object):
          else:
              return self.mac(key, self.digestmod(), default_backend())
  
@@ -42,7 +42,7 @@ index 69e7ae3b..0c69ba1a 100644
  
          @return: the signed packet
          """
-@@ -534,16 +539,20 @@ class AuthAlgo(object):
+@@ -534,16 +534,20 @@ class AuthAlgo(object):
  
          if pkt.haslayer(ESP):
              mac.update(raw(pkt[ESP]))
@@ -64,7 +64,7 @@ index 69e7ae3b..0c69ba1a 100644
          """
          Check that the integrity check value (icv) of a packet is valid.
  
-@@ -574,6 +583,8 @@ class AuthAlgo(object):
+@@ -574,6 +578,8 @@ class AuthAlgo(object):
              clone = zero_mutable_fields(pkt.copy(), sending=False)
  
          mac.update(raw(clone))
@@ -73,7 +73,7 @@ index 69e7ae3b..0c69ba1a 100644
          computed_icv = mac.finalize()[:self.icv_size]
  
          # XXX: Cannot use mac.verify because the ICV can be truncated
-@@ -757,7 +768,8 @@ class SecurityAssociation(object):
+@@ -757,7 +763,8 @@ class SecurityAssociation(object):
      SUPPORTED_PROTOS = (IP, IPv6)
  
      def __init__(self, proto, spi, seq_num=1, crypt_algo=None, crypt_key=None,
@@ -83,7 +83,7 @@ index 69e7ae3b..0c69ba1a 100644
          """
          @param proto: the IPsec proto to use (ESP or AH)
          @param spi: the Security Parameters Index of this SA
-@@ -771,6 +783,7 @@ class SecurityAssociation(object):
+@@ -771,6 +778,7 @@ class SecurityAssociation(object):
                                to encapsulate the encrypted packets.
          @param nat_t_header: an instance of a UDP header that will be used
                               for NAT-Traversal.
@@ -91,7 +91,7 @@ index 69e7ae3b..0c69ba1a 100644
          """
  
          if proto not in (ESP, AH, ESP.name, AH.name):
-@@ -782,6 +795,7 @@ class SecurityAssociation(object):
+@@ -782,6 +790,7 @@ class SecurityAssociation(object):
  
          self.spi = spi
          self.seq_num = seq_num
@@ -99,10 +99,16 @@ index 69e7ae3b..0c69ba1a 100644
  
          if crypt_algo:
              if crypt_algo not in CRYPT_ALGOS:
-@@ -827,6 +841,17 @@ class SecurityAssociation(object):
+@@ -827,6 +836,23 @@ class SecurityAssociation(object):
              raise TypeError('packet spi=0x%x does not match the SA spi=0x%x' %
                              (pkt.spi, self.spi))
  
++    def build_aead(self, esp):
++        if self.use_esn:
++            return (struct.pack('!LLL', esp.spi, self.seq_num >> 32, esp.seq))
++        else:
++            return (struct.pack('!LL', esp.spi, esp.seq))
++
 +    def build_seq_num(self, num):
 +        # only lower order bits are  transmitted
 +        # higher order bits are used in the ICV
@@ -117,7 +123,7 @@ index 69e7ae3b..0c69ba1a 100644
      def _encrypt_esp(self, pkt, seq_num=None, iv=None):
  
          if iv is None:
-@@ -835,7 +860,8 @@ class SecurityAssociation(object):
+@@ -835,7 +861,8 @@ class SecurityAssociation(object):
              if len(iv) != self.crypt_algo.iv_size:
                  raise TypeError('iv length must be %s' % self.crypt_algo.iv_size)
  
@@ -127,7 +133,7 @@ index 69e7ae3b..0c69ba1a 100644
  
          if self.tunnel_header:
              tunnel = self.tunnel_header.copy()
-@@ -857,7 +883,7 @@ class SecurityAssociation(object):
+@@ -857,7 +884,7 @@ class SecurityAssociation(object):
          esp = self.crypt_algo.pad(esp)
          esp = self.crypt_algo.encrypt(self, esp, self.crypt_key)
  
@@ -136,7 +142,7 @@ index 69e7ae3b..0c69ba1a 100644
  
          if self.nat_t_header:
              nat_t_header = self.nat_t_header.copy()
-@@ -884,7 +910,8 @@ class SecurityAssociation(object):
+@@ -884,7 +911,8 @@ class SecurityAssociation(object):
  
      def _encrypt_ah(self, pkt, seq_num=None):
  
@@ -146,7 +152,7 @@ index 69e7ae3b..0c69ba1a 100644
                  icv = b"\x00" * self.auth_algo.icv_size)
  
          if self.tunnel_header:
-@@ -924,7 +951,8 @@ class SecurityAssociation(object):
+@@ -924,7 +952,8 @@ class SecurityAssociation(object):
          else:
              ip_header.plen = len(ip_header.payload) + len(ah) + len(payload)
  
@@ -156,7 +162,7 @@ index 69e7ae3b..0c69ba1a 100644
  
          # sequence number must always change, unless specified by the user
          if seq_num is None:
-@@ -955,11 +983,12 @@ class SecurityAssociation(object):
+@@ -955,11 +984,12 @@ class SecurityAssociation(object):
  
      def _decrypt_esp(self, pkt, verify=True):
  
@@ -170,7 +176,7 @@ index 69e7ae3b..0c69ba1a 100644
  
          esp = self.crypt_algo.decrypt(self, encrypted, self.crypt_key,
                                        self.crypt_algo.icv_size or
-@@ -998,9 +1027,11 @@ class SecurityAssociation(object):
+@@ -998,9 +1028,11 @@ class SecurityAssociation(object):
  
      def _decrypt_ah(self, pkt, verify=True):