5d4b8912d2
Type: fix Change-Id: I7e041b666dabd90df23a920a1f1d99db4c10ddfe Signed-off-by: snaramre <snaramre@cisco.com>
163 lines
6.2 KiB
Diff
163 lines
6.2 KiB
Diff
diff --git a/scapy/layers/ipsec.py b/scapy/layers/ipsec.py
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index f8c601fa..f566d288 100644
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--- a/scapy/layers/ipsec.py
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+++ b/scapy/layers/ipsec.py
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@@ -359,11 +359,8 @@ class CryptAlgo(object):
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encryptor = cipher.encryptor()
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if self.is_aead:
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- if esn_en:
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- aad = struct.pack('!LLL', esp.spi, esn, esp.seq)
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- else:
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- aad = struct.pack('!LL', esp.spi, esp.seq)
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- encryptor.authenticate_additional_data(aad)
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+ encryptor.authenticate_additional_data(sa.build_aead(esp))
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+
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data = encryptor.update(data) + encryptor.finalize()
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data += encryptor.tag[:self.icv_size]
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else:
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@@ -401,12 +398,7 @@ class CryptAlgo(object):
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if self.is_aead:
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# Tag value check is done during the finalize method
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- if esn_en:
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- decryptor.authenticate_additional_data(
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- struct.pack('!LLL', esp.spi, esn, esp.seq))
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- else:
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- decryptor.authenticate_additional_data(
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- struct.pack('!LL', esp.spi, esp.seq))
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+ decryptor.authenticate_additional_data(sa.build_aead(esp))
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try:
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data = decryptor.update(data) + decryptor.finalize()
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except InvalidTag as err:
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@@ -545,7 +537,7 @@ class AuthAlgo(object):
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else:
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return self.mac(key, self.digestmod(), default_backend())
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- def sign(self, pkt, key):
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+ def sign(self, pkt, key, trailer=None):
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"""
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Sign an IPsec (ESP or AH) packet with this algo.
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@@ -561,16 +553,20 @@ class AuthAlgo(object):
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if pkt.haslayer(ESP):
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mac.update(raw(pkt[ESP]))
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+ if trailer:
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+ mac.update(trailer)
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pkt[ESP].data += mac.finalize()[:self.icv_size]
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elif pkt.haslayer(AH):
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clone = zero_mutable_fields(pkt.copy(), sending=True)
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mac.update(raw(clone))
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+ if trailer:
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+ mac.update(trailer)
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pkt[AH].icv = mac.finalize()[:self.icv_size]
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return pkt
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- def verify(self, pkt, key):
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+ def verify(self, pkt, key, trailer):
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"""
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Check that the integrity check value (icv) of a packet is valid.
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@@ -602,6 +598,8 @@ class AuthAlgo(object):
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clone = zero_mutable_fields(pkt.copy(), sending=False)
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mac.update(raw(clone))
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+ if trailer:
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+ mac.update(trailer) # bytearray(4)) #raw(trailer))
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computed_icv = mac.finalize()[:self.icv_size]
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# XXX: Cannot use mac.verify because the ICV can be truncated
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@@ -864,6 +862,23 @@ class SecurityAssociation(object):
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raise TypeError('nat_t_header must be %s' % UDP.name)
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self.nat_t_header = nat_t_header
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+ def build_aead(self, esp):
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+ if self.esn_en:
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+ return (struct.pack('!LLL', esp.spi, self.seq_num >> 32, esp.seq))
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+ else:
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+ return (struct.pack('!LL', esp.spi, esp.seq))
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+
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+ def build_seq_num(self, num):
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+ # only lower order bits are transmitted
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+ # higher order bits are used in the ICV
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+ lower = num & 0xffffffff
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+ upper = num >> 32
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+
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+ if self.esn_en:
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+ return lower, struct.pack("!I", upper)
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+ else:
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+ return lower, None
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+
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def check_spi(self, pkt):
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if pkt.spi != self.spi:
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raise TypeError('packet spi=0x%x does not match the SA spi=0x%x' %
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@@ -877,7 +892,8 @@ class SecurityAssociation(object):
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if len(iv) != self.crypt_algo.iv_size:
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raise TypeError('iv length must be %s' % self.crypt_algo.iv_size) # noqa: E501
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- esp = _ESPPlain(spi=self.spi, seq=seq_num or self.seq_num, iv=iv)
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+ low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
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+ esp = _ESPPlain(spi=self.spi, seq=low_seq_num, iv=iv)
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if self.tunnel_header:
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tunnel = self.tunnel_header.copy()
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@@ -901,7 +917,7 @@ class SecurityAssociation(object):
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esn_en=esn_en or self.esn_en,
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esn=esn or self.esn)
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- self.auth_algo.sign(esp, self.auth_key)
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+ self.auth_algo.sign(esp, self.auth_key, high_seq_num)
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if self.nat_t_header:
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nat_t_header = self.nat_t_header.copy()
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@@ -928,7 +944,8 @@ class SecurityAssociation(object):
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def _encrypt_ah(self, pkt, seq_num=None):
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- ah = AH(spi=self.spi, seq=seq_num or self.seq_num,
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+ low_seq_num, high_seq_num = self.build_seq_num(seq_num or self.seq_num)
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+ ah = AH(spi=self.spi, seq=low_seq_num,
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icv=b"\x00" * self.auth_algo.icv_size)
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if self.tunnel_header:
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@@ -968,7 +985,8 @@ class SecurityAssociation(object):
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else:
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ip_header.plen = len(ip_header.payload) + len(ah) + len(payload)
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- signed_pkt = self.auth_algo.sign(ip_header / ah / payload, self.auth_key) # noqa: E501
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+ signed_pkt = self.auth_algo.sign(ip_header / ah / payload,
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+ self.auth_key, high_seq_num) # noqa: E501
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# sequence number must always change, unless specified by the user
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if seq_num is None:
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@@ -1005,11 +1023,12 @@ class SecurityAssociation(object):
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def _decrypt_esp(self, pkt, verify=True, esn_en=None, esn=None):
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+ low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
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encrypted = pkt[ESP]
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if verify:
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self.check_spi(pkt)
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- self.auth_algo.verify(encrypted, self.auth_key)
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+ self.auth_algo.verify(encrypted, self.auth_key, high_seq_num)
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esp = self.crypt_algo.decrypt(self, encrypted, self.crypt_key,
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self.crypt_algo.icv_size or
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@@ -1050,9 +1069,10 @@ class SecurityAssociation(object):
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def _decrypt_ah(self, pkt, verify=True):
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+ low_seq_num, high_seq_num = self.build_seq_num(self.seq_num)
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if verify:
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self.check_spi(pkt)
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- self.auth_algo.verify(pkt, self.auth_key)
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+ self.auth_algo.verify(pkt, self.auth_key, high_seq_num)
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ah = pkt[AH]
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payload = ah.payload
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