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>
diff --git a/src/plugins/crypto_openssl/main.c b/src/plugins/crypto_openssl/main.c
index fd749d0..7362d6b 100644
--- a/src/plugins/crypto_openssl/main.c
+++ b/src/plugins/crypto_openssl/main.c
@@ -169,7 +169,7 @@
else
{
n_fail++;
- op->status = VNET_CRYPTO_OP_STATUS_FAIL_DECRYPT;
+ op->status = VNET_CRYPTO_OP_STATUS_FAIL_BAD_HMAC;
}
}
return n_ops - n_fail;
diff --git a/src/plugins/dpdk/ipsec/esp_decrypt.c b/src/plugins/dpdk/ipsec/esp_decrypt.c
index 4982db7..a82f63e 100644
--- a/src/plugins/dpdk/ipsec/esp_decrypt.c
+++ b/src/plugins/dpdk/ipsec/esp_decrypt.c
@@ -235,7 +235,8 @@
}
/* anti-replay check */
- if (ipsec_sa_anti_replay_check (sa0, &esp0->seq))
+ if (ipsec_sa_anti_replay_check
+ (sa0, clib_host_to_net_u32 (esp0->seq)))
{
clib_warning ("failed anti-replay check");
if (is_ip6)
@@ -549,7 +550,8 @@
iv_size = cipher_alg->iv_len;
- ipsec_sa_anti_replay_advance (sa0, esp0->seq);
+ ipsec_sa_anti_replay_advance (sa0,
+ clib_host_to_net_u32 (esp0->seq));
/* if UDP encapsulation is used adjust the address of the IP header */
if (ipsec_sa_is_set_UDP_ENCAP (sa0)
diff --git a/src/vnet/crypto/crypto.h b/src/vnet/crypto/crypto.h
index 9c15d53..9326a07 100644
--- a/src/vnet/crypto/crypto.h
+++ b/src/vnet/crypto/crypto.h
@@ -65,8 +65,7 @@
_(PENDING, "pending") \
_(COMPLETED, "completed") \
_(FAIL_NO_HANDLER, "no-handler") \
- _(FAIL_BAD_HMAC, "bad-hmac") \
- _(FAIL_DECRYPT, "decrypt-fail")
+ _(FAIL_BAD_HMAC, "bad-hmac")
typedef enum
{
diff --git a/src/vnet/ipsec/ah_decrypt.c b/src/vnet/ipsec/ah_decrypt.c
index 741fa91..bc6b5c4 100644
--- a/src/vnet/ipsec/ah_decrypt.c
+++ b/src/vnet/ipsec/ah_decrypt.c
@@ -203,7 +203,7 @@
pd->seq = clib_host_to_net_u32 (ah0->seq_no);
/* anti-replay check */
- if (ipsec_sa_anti_replay_check (sa0, &ah0->seq_no))
+ if (ipsec_sa_anti_replay_check (sa0, pd->seq))
{
b[0]->error = node->errors[AH_DECRYPT_ERROR_REPLAY];
next[0] = AH_DECRYPT_NEXT_DROP;
@@ -303,7 +303,7 @@
if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
{
- ipsec_sa_anti_replay_advance (sa0, clib_host_to_net_u32 (pd->seq));
+ ipsec_sa_anti_replay_advance (sa0, pd->seq);
}
u16 ah_hdr_len = sizeof (ah_header_t) + pd->icv_size
diff --git a/src/vnet/ipsec/esp_decrypt.c b/src/vnet/ipsec/esp_decrypt.c
index 48f08f4..c2b9bf4 100644
--- a/src/vnet/ipsec/esp_decrypt.c
+++ b/src/vnet/ipsec/esp_decrypt.c
@@ -67,6 +67,8 @@
typedef struct
{
u32 seq;
+ u32 sa_seq;
+ u32 sa_seq_hi;
ipsec_crypto_alg_t crypto_alg;
ipsec_integ_alg_t integ_alg;
} esp_decrypt_trace_t;
@@ -79,9 +81,11 @@
CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);
- s = format (s, "esp: crypto %U integrity %U seq %u",
- format_ipsec_crypto_alg, t->crypto_alg,
- format_ipsec_integ_alg, t->integ_alg, t->seq);
+ s =
+ format (s,
+ "esp: crypto %U integrity %U pkt-seq %d sa-seq %u sa-seq-hi %u",
+ format_ipsec_crypto_alg, t->crypto_alg, format_ipsec_integ_alg,
+ t->integ_alg, t->seq, t->sa_seq, t->sa_seq_hi);
return s;
}
@@ -99,12 +103,13 @@
u64 sa_data;
};
+ u32 seq;
i16 current_data;
i16 current_length;
u16 hdr_sz;
} esp_decrypt_packet_data_t;
-STATIC_ASSERT_SIZEOF (esp_decrypt_packet_data_t, 2 * sizeof (u64));
+STATIC_ASSERT_SIZEOF (esp_decrypt_packet_data_t, 3 * sizeof (u64));
#define ESP_ENCRYPT_PD_F_FD_TRANSPORT (1 << 2)
@@ -177,6 +182,7 @@
pd->current_length = b[0]->current_length;
pd->hdr_sz = pd->current_data - vnet_buffer (b[0])->l3_hdr_offset;
payload = b[0]->data + pd->current_data;
+ pd->seq = clib_host_to_net_u32 (((esp_header_t *) payload)->seq);
/* we need 4 extra bytes for HMAC calculation when ESN are used */
if (ipsec_sa_is_set_USE_ESN (sa0) && pd->icv_sz &&
@@ -188,7 +194,7 @@
}
/* anti-reply check */
- if (ipsec_sa_anti_replay_check (sa0, &((esp_header_t *) payload)->seq))
+ if (ipsec_sa_anti_replay_check (sa0, pd->seq))
{
b[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
next[0] = ESP_DECRYPT_NEXT_DROP;
@@ -221,10 +227,11 @@
op->len = len;
if (ipsec_sa_is_set_USE_ESN (sa0))
{
- /* shift ICV for 4 bytes to insert ESN */
+ /* shift ICV by 4 bytes to insert ESN */
+ u32 seq_hi = clib_host_to_net_u32 (sa0->seq_hi);
u8 tmp[ESP_MAX_ICV_SIZE], sz = sizeof (sa0->seq_hi);
clib_memcpy_fast (tmp, payload + len, ESP_MAX_ICV_SIZE);
- clib_memcpy_fast (payload + len, &sa0->seq_hi, sz);
+ clib_memcpy_fast (payload + len, &seq_hi, sz);
clib_memcpy_fast (payload + len + sz, tmp, ESP_MAX_ICV_SIZE);
op->len += sz;
op->digest += sz;
@@ -368,9 +375,8 @@
goto trace;
sa0 = vec_elt_at_index (im->sad, pd->sa_index);
- u8 *payload = b[0]->data + pd->current_data;
- ipsec_sa_anti_replay_advance (sa0, ((esp_header_t *) payload)->seq);
+ ipsec_sa_anti_replay_advance (sa0, pd->seq);
esp_footer_t *f = (esp_footer_t *) (b[0]->data + pd->current_data +
pd->current_length - sizeof (*f) -
@@ -485,13 +491,14 @@
if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
{
esp_decrypt_trace_t *tr;
- u8 *payload = b[0]->data + pd->current_data;
tr = vlib_add_trace (vm, node, b[0], sizeof (*tr));
sa0 = pool_elt_at_index (im->sad,
vnet_buffer (b[0])->ipsec.sad_index);
tr->crypto_alg = sa0->crypto_alg;
tr->integ_alg = sa0->integ_alg;
- tr->seq = clib_host_to_net_u32 (((esp_header_t *) payload)->seq);
+ tr->seq = pd->seq;
+ tr->sa_seq = sa0->last_seq;
+ tr->sa_seq_hi = sa0->seq_hi;
}
/* next */
diff --git a/src/vnet/ipsec/esp_encrypt.c b/src/vnet/ipsec/esp_encrypt.c
index 041b268..47c079d 100644
--- a/src/vnet/ipsec/esp_encrypt.c
+++ b/src/vnet/ipsec/esp_encrypt.c
@@ -65,6 +65,7 @@
u32 sa_index;
u32 spi;
u32 seq;
+ u32 sa_seq_hi;
u8 udp_encap;
ipsec_crypto_alg_t crypto_alg;
ipsec_integ_alg_t integ_alg;
@@ -80,8 +81,9 @@
s =
format (s,
- "esp: sa-index %d spi %u (0x%08x) seq %u crypto %U integrity %U%s",
- t->sa_index, t->spi, t->spi, t->seq, format_ipsec_crypto_alg,
+ "esp: sa-index %d spi %u (0x%08x) seq %u sa-seq-hi %u crypto %U integrity %U%s",
+ t->sa_index, t->spi, t->spi, t->seq, t->sa_seq_hi,
+ format_ipsec_crypto_alg,
t->crypto_alg, format_ipsec_integ_alg, t->integ_alg,
t->udp_encap ? " udp-encap-enabled" : "");
return s;
@@ -521,7 +523,8 @@
sizeof (*tr));
tr->sa_index = sa_index0;
tr->spi = sa0->spi;
- tr->seq = sa0->seq - 1;
+ tr->seq = sa0->seq;
+ tr->sa_seq_hi = sa0->seq_hi;
tr->udp_encap = ipsec_sa_is_set_UDP_ENCAP (sa0);
tr->crypto_alg = sa0->crypto_alg;
tr->integ_alg = sa0->integ_alg;
diff --git a/src/vnet/ipsec/ipsec_sa.h b/src/vnet/ipsec/ipsec_sa.h
index 811f4ca..86d76b3 100644
--- a/src/vnet/ipsec/ipsec_sa.h
+++ b/src/vnet/ipsec/ipsec_sa.h
@@ -19,8 +19,6 @@
#include <vnet/ip/ip.h>
#include <vnet/fib/fib_node.h>
-#define IPSEC_SA_ANTI_REPLAY_WINDOW_SIZE (64)
-
#define foreach_ipsec_crypto_alg \
_ (0, NONE, "none") \
_ (1, AES_CBC_128, "aes-cbc-128") \
@@ -232,18 +230,34 @@
va_list * args);
extern uword unformat_ipsec_key (unformat_input_t * input, va_list * args);
+/*
+ * Anti Replay definitions
+ */
+
+#define IPSEC_SA_ANTI_REPLAY_WINDOW_SIZE (64)
+#define IPSEC_SA_ANTI_REPLAY_WINDOW_MAX_INDEX (IPSEC_SA_ANTI_REPLAY_WINDOW_SIZE-1)
+
+/*
+ * sequence number less than the lower bound are outside of the window
+ * From RFC4303 Appendix A:
+ * Bl = Tl - W + 1
+ */
+#define IPSEC_SA_ANTI_REPLAY_WINDOW_LOWER_BOUND(_tl) (_tl - IPSEC_SA_ANTI_REPLAY_WINDOW_SIZE + 1)
+
+/*
+ * Anti replay check.
+ * inputs need to be in host byte order.
+ */
always_inline int
-ipsec_sa_anti_replay_check (ipsec_sa_t * sa, u32 * seqp)
+ipsec_sa_anti_replay_check (ipsec_sa_t * sa, u32 seq)
{
- u32 seq, diff, tl, th;
+ u32 diff, tl, th;
+
if ((sa->flags & IPSEC_SA_FLAG_USE_ANTI_REPLAY) == 0)
return 0;
- seq = clib_net_to_host_u32 (*seqp);
-
- if ((sa->flags & IPSEC_SA_FLAG_USE_ESN) == 0)
+ if (!ipsec_sa_is_set_USE_ESN (sa))
{
-
if (PREDICT_TRUE (seq > sa->last_seq))
return 0;
@@ -261,50 +275,113 @@
th = sa->last_seq_hi;
diff = tl - seq;
- if (PREDICT_TRUE (tl >= (IPSEC_SA_ANTI_REPLAY_WINDOW_SIZE - 1)))
+ if (PREDICT_TRUE (tl >= (IPSEC_SA_ANTI_REPLAY_WINDOW_MAX_INDEX)))
{
- if (seq >= (tl - IPSEC_SA_ANTI_REPLAY_WINDOW_SIZE + 1))
+ /*
+ * the last sequence number VPP recieved is more than one
+ * window size greater than zero.
+ * Case A from RFC4303 Appendix A.
+ */
+ if (seq < IPSEC_SA_ANTI_REPLAY_WINDOW_LOWER_BOUND (tl))
{
- sa->seq_hi = th;
- if (seq <= tl)
- return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
- else
- return 0;
+ /*
+ * the received sequence number is lower than the lower bound
+ * of the window, this could mean either a replay packet or that
+ * the high sequence number has wrapped. if it decrypts corrently
+ * then it's the latter.
+ */
+ sa->seq_hi = th + 1;
+ return 0;
}
else
{
- sa->seq_hi = th + 1;
- return 0;
+ /*
+ * the recieved sequence number greater than the low
+ * end of the window.
+ */
+ sa->seq_hi = th;
+ if (seq <= tl)
+ /*
+ * The recieved seq number is within bounds of the window
+ * check if it's a duplicate
+ */
+ return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
+ else
+ /*
+ * The received sequence number is greater than the window
+ * upper bound. this packet will move the window along, assuming
+ * it decrypts correctly.
+ */
+ return 0;
}
}
else
{
- if (seq >= (tl - IPSEC_SA_ANTI_REPLAY_WINDOW_SIZE + 1))
+ /*
+ * the last sequence number VPP recieved is within one window
+ * size of zero, i.e. 0 < TL < WINDOW_SIZE, the lower bound is thus a
+ * large sequence number.
+ * Note that the check below uses unsiged integer arthimetic, so the
+ * RHS will be a larger number.
+ * Case B from RFC4303 Appendix A.
+ */
+ if (seq < IPSEC_SA_ANTI_REPLAY_WINDOW_LOWER_BOUND (tl))
{
- sa->seq_hi = th - 1;
- return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
+ /*
+ * the sequence number is less than the lower bound.
+ */
+ if (seq <= tl)
+ {
+ /*
+ * the packet is within the window upper bound.
+ * check for duplicates.
+ */
+ sa->seq_hi = th;
+ return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
+ }
+ else
+ {
+ /*
+ * the packet is less the window lower bound or greater than
+ * the higher bound, depending on how you look at it...
+ * We're assuming, given that the last sequence number received,
+ * TL < WINDOW_SIZE, that a largeer seq num is more likely to be
+ * a packet that moves the window forward, than a packet that has
+ * wrapped the high sequence again. If it were the latter then
+ * we've lost close to 2^32 packets.
+ */
+ sa->seq_hi = th;
+ return 0;
+ }
}
else
{
- sa->seq_hi = th;
- if (seq <= tl)
- return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
- else
- return 0;
+ /*
+ * the packet seq number is between the lower bound (a large nubmer)
+ * and MAX_SEQ_NUM. This is in the window since the window upper bound
+ * tl > 0.
+ * However, since TL is the other side of 0 to the received
+ * packet, the SA has moved on to a higher sequence number.
+ */
+ sa->seq_hi = th - 1;
+ return (sa->replay_window & (1ULL << diff)) ? 1 : 0;
}
}
return 0;
}
+/*
+ * Anti replay window advance
+ * inputs need to be in host byte order.
+ */
always_inline void
-ipsec_sa_anti_replay_advance (ipsec_sa_t * sa, u32 seqp)
+ipsec_sa_anti_replay_advance (ipsec_sa_t * sa, u32 seq)
{
- u32 pos, seq;
+ u32 pos;
if (PREDICT_TRUE (sa->flags & IPSEC_SA_FLAG_USE_ANTI_REPLAY) == 0)
return;
- seq = clib_host_to_net_u32 (seqp);
if (PREDICT_TRUE (sa->flags & IPSEC_SA_FLAG_USE_ESN))
{
int wrap = sa->seq_hi - sa->last_seq_hi;
diff --git a/test/patches/scapy-2.4/ipsec.patch b/test/patches/scapy-2.4/ipsec.patch
index 731fe3c..083b0b9 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 @@
@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 @@
"""
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 @@
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 @@
"""
@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 @@
"""
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
# 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 @@
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):
diff --git a/test/template_ipsec.py b/test/template_ipsec.py
index e40fa56..25cff7f 100644
--- a/test/template_ipsec.py
+++ b/test/template_ipsec.py
@@ -84,14 +84,18 @@
self.nat_header = None
+def mk_scapy_crpyt_key(p):
+ if p.crypt_algo == "AES-GCM":
+ return p.crypt_key + struct.pack("!I", p.salt)
+ else:
+ return p.crypt_key
+
+
def config_tun_params(p, encryption_type, tun_if):
ip_class_by_addr_type = {socket.AF_INET: IP, socket.AF_INET6: IPv6}
use_esn = bool(p.flags & (VppEnum.vl_api_ipsec_sad_flags_t.
IPSEC_API_SAD_FLAG_USE_ESN))
- if p.crypt_algo == "AES-GCM":
- crypt_key = p.crypt_key + struct.pack("!I", p.salt)
- else:
- crypt_key = p.crypt_key
+ crypt_key = mk_scapy_crpyt_key(p)
p.scapy_tun_sa = SecurityAssociation(
encryption_type, spi=p.vpp_tun_spi,
crypt_algo=p.crypt_algo,
@@ -117,10 +121,7 @@
def config_tra_params(p, encryption_type):
use_esn = bool(p.flags & (VppEnum.vl_api_ipsec_sad_flags_t.
IPSEC_API_SAD_FLAG_USE_ESN))
- if p.crypt_algo == "AES-GCM":
- crypt_key = p.crypt_key + struct.pack("!I", p.salt)
- else:
- crypt_key = p.crypt_key
+ crypt_key = mk_scapy_crpyt_key(p)
p.scapy_tra_sa = SecurityAssociation(
encryption_type,
spi=p.vpp_tra_spi,
@@ -269,32 +270,68 @@
class IpsecTra4(object):
""" verify methods for Transport v4 """
- def verify_tra_anti_replay(self, count=1):
+ def verify_tra_anti_replay(self):
p = self.params[socket.AF_INET]
use_esn = p.vpp_tra_sa.use_esn
- # fire in a packet with seq number 1
- pkt = (Ether(src=self.tra_if.remote_mac,
- dst=self.tra_if.local_mac) /
- p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
- dst=self.tra_if.local_ip4) /
- ICMP(),
- seq_num=1))
- recv_pkts = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
+ seq_cycle_node_name = ('/err/%s/sequence number cycled' %
+ self.tra4_encrypt_node_name)
+ replay_node_name = ('/err/%s/SA replayed packet' %
+ self.tra4_decrypt_node_name)
+ if ESP == self.encryption_type and p.crypt_algo == "AES-GCM":
+ hash_failed_node_name = ('/err/%s/ESP decryption failed' %
+ self.tra4_decrypt_node_name)
+ else:
+ hash_failed_node_name = ('/err/%s/Integrity check failed' %
+ self.tra4_decrypt_node_name)
+ replay_count = self.statistics.get_err_counter(replay_node_name)
+ hash_failed_count = self.statistics.get_err_counter(
+ hash_failed_node_name)
+ seq_cycle_count = self.statistics.get_err_counter(seq_cycle_node_name)
- # now move the window over to 235
+ if ESP == self.encryption_type:
+ undersize_node_name = ('/err/%s/undersized packet' %
+ self.tra4_decrypt_node_name)
+ undersize_count = self.statistics.get_err_counter(
+ undersize_node_name)
+
+ #
+ # send packets with seq numbers 1->34
+ # this means the window size is still in Case B (see RFC4303
+ # Appendix A)
+ #
+ # for reasons i haven't investigated Scapy won't create a packet with
+ # seq_num=0
+ #
+ pkts = [(Ether(src=self.tra_if.remote_mac,
+ dst=self.tra_if.local_mac) /
+ p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
+ dst=self.tra_if.local_ip4) /
+ ICMP(),
+ seq_num=seq))
+ for seq in range(1, 34)]
+ recv_pkts = self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+ # replayed packets are dropped
+ self.send_and_assert_no_replies(self.tra_if, pkts)
+ replay_count += len(pkts)
+ self.assert_error_counter_equal(replay_node_name, replay_count)
+
+ #
+ # now move the window over to 257 (more than one byte) and into Case A
+ #
pkt = (Ether(src=self.tra_if.remote_mac,
dst=self.tra_if.local_mac) /
p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
dst=self.tra_if.local_ip4) /
ICMP(),
- seq_num=235))
+ seq_num=257))
recv_pkts = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
# replayed packets are dropped
self.send_and_assert_no_replies(self.tra_if, pkt * 3)
- self.assert_error_counter_equal(
- '/err/%s/SA replayed packet' % self.tra4_decrypt_node_name, 3)
+ replay_count += 3
+ self.assert_error_counter_equal(replay_node_name, replay_count)
# the window size is 64 packets
# in window are still accepted
@@ -303,14 +340,14 @@
p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
dst=self.tra_if.local_ip4) /
ICMP(),
- seq_num=172))
+ seq_num=200))
recv_pkts = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
# a packet that does not decrypt does not move the window forward
bogus_sa = SecurityAssociation(self.encryption_type,
p.vpp_tra_spi,
crypt_algo=p.crypt_algo,
- crypt_key=p.crypt_key[::-1],
+ crypt_key=mk_scapy_crpyt_key(p)[::-1],
auth_algo=p.auth_algo,
auth_key=p.auth_key[::-1])
pkt = (Ether(src=self.tra_if.remote_mac,
@@ -321,8 +358,9 @@
seq_num=350))
self.send_and_assert_no_replies(self.tra_if, pkt * 17)
- self.assert_error_counter_equal(
- '/err/%s/Integrity check failed' % self.tra4_decrypt_node_name, 17)
+ hash_failed_count += 17
+ self.assert_error_counter_equal(hash_failed_node_name,
+ hash_failed_count)
# a malformed 'runt' packet
# created by a mis-constructed SA
@@ -337,8 +375,9 @@
seq_num=350))
self.send_and_assert_no_replies(self.tra_if, pkt * 17)
- self.assert_error_counter_equal(
- '/err/%s/undersized packet' % self.tra4_decrypt_node_name, 17)
+ undersize_count += 17
+ self.assert_error_counter_equal(undersize_node_name,
+ undersize_count)
# which we can determine since this packet is still in the window
pkt = (Ether(src=self.tra_if.remote_mac,
@@ -349,7 +388,11 @@
seq_num=234))
self.send_and_expect(self.tra_if, [pkt], self.tra_if)
+ #
# out of window are dropped
+ # this is Case B. So VPP will consider this to be a high seq num wrap
+ # and so the decrypt attempt will fail
+ #
pkt = (Ether(src=self.tra_if.remote_mac,
dst=self.tra_if.local_mac) /
p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
@@ -361,44 +404,59 @@
if use_esn:
# an out of window error with ESN looks like a high sequence
# wrap. but since it isn't then the verify will fail.
- self.assert_error_counter_equal(
- '/err/%s/Integrity check failed' %
- self.tra4_decrypt_node_name, 34)
+ hash_failed_count += 17
+ self.assert_error_counter_equal(hash_failed_node_name,
+ hash_failed_count)
else:
- self.assert_error_counter_equal(
- '/err/%s/SA replayed packet' %
- self.tra4_decrypt_node_name, 20)
+ replay_count += 17
+ self.assert_error_counter_equal(replay_node_name,
+ replay_count)
- # valid packet moves the window over to 236
+ # valid packet moves the window over to 258
pkt = (Ether(src=self.tra_if.remote_mac,
dst=self.tra_if.local_mac) /
p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
dst=self.tra_if.local_ip4) /
ICMP(),
- seq_num=236))
+ seq_num=258))
rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
- # move VPP's SA to just before the seq-number wrap
+ #
+ # move VPP's SA TX seq-num to just before the seq-number wrap.
+ # then fire in a packet that VPP should drop on TX because it
+ # causes the TX seq number to wrap; unless we're using extened sequence
+ # numbers.
+ #
self.vapi.cli("test ipsec sa %d seq 0xffffffff" % p.scapy_tra_sa_id)
+ self.logger.info(self.vapi.ppcli("show ipsec sa 0"))
+ self.logger.info(self.vapi.ppcli("show ipsec sa 1"))
- # then fire in a packet that VPP should drop because it causes the
- # seq number to wrap unless we're using extended.
- pkt = (Ether(src=self.tra_if.remote_mac,
- dst=self.tra_if.local_mac) /
- p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
- dst=self.tra_if.local_ip4) /
- ICMP(),
- seq_num=237))
+ pkts = [(Ether(src=self.tra_if.remote_mac,
+ dst=self.tra_if.local_mac) /
+ p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
+ dst=self.tra_if.local_ip4) /
+ ICMP(),
+ seq_num=seq))
+ for seq in range(259, 280)]
if use_esn:
- rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
- # in order to decrpyt the high order number needs to wrap
- p.vpp_tra_sa.seq_num = 0x100000000
- decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
+ rxs = self.send_and_expect(self.tra_if, pkts, self.tra_if)
- # send packets with high bits set
+ #
+ # in order for scapy to decrypt its SA's high order number needs
+ # to wrap
+ #
+ p.vpp_tra_sa.seq_num = 0x100000000
+ for rx in rxs:
+ decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
+
+ #
+ # wrap scapy's TX high sequence number. VPP is in case B, so it
+ # will consider this a high seq wrap also.
+ # The low seq num we set it to will place VPP's RX window in Case A
+ #
p.scapy_tra_sa.seq_num = 0x100000005
pkt = (Ether(src=self.tra_if.remote_mac,
dst=self.tra_if.local_mac) /
@@ -407,13 +465,72 @@
ICMP(),
seq_num=0x100000005))
rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
- # in order to decrpyt the high order number needs to wrap
decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
+
+ #
+ # A packet that has seq num between (2^32-64) and 5 is within
+ # the window
+ #
+ p.scapy_tra_sa.seq_num = 0xfffffffd
+ pkt = (Ether(src=self.tra_if.remote_mac,
+ dst=self.tra_if.local_mac) /
+ p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
+ dst=self.tra_if.local_ip4) /
+ ICMP(),
+ seq_num=0xfffffffd))
+ rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
+ decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
+
+ #
+ # While in case A we cannot wrap the high sequence number again
+ # becuase VPP will consider this packet to be one that moves the
+ # window forward
+ #
+ pkt = (Ether(src=self.tra_if.remote_mac,
+ dst=self.tra_if.local_mac) /
+ p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
+ dst=self.tra_if.local_ip4) /
+ ICMP(),
+ seq_num=0x200000999))
+ self.send_and_assert_no_replies(self.tra_if, [pkt], self.tra_if)
+
+ hash_failed_count += 1
+ self.assert_error_counter_equal(hash_failed_node_name,
+ hash_failed_count)
+
+ #
+ # but if we move the wondow forward to case B, then we can wrap
+ # again
+ #
+ p.scapy_tra_sa.seq_num = 0x100000555
+ pkt = (Ether(src=self.tra_if.remote_mac,
+ dst=self.tra_if.local_mac) /
+ p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
+ dst=self.tra_if.local_ip4) /
+ ICMP(),
+ seq_num=0x100000555))
+ rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
+ decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
+
+ p.scapy_tra_sa.seq_num = 0x200000444
+ pkt = (Ether(src=self.tra_if.remote_mac,
+ dst=self.tra_if.local_mac) /
+ p.scapy_tra_sa.encrypt(IP(src=self.tra_if.remote_ip4,
+ dst=self.tra_if.local_ip4) /
+ ICMP(),
+ seq_num=0x200000444))
+ rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
+ decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
+
else:
- self.send_and_assert_no_replies(self.tra_if, [pkt])
- self.assert_error_counter_equal(
- '/err/%s/sequence number cycled' %
- self.tra4_encrypt_node_name, 1)
+ #
+ # without ESN TX sequence numbers can't wrap and packets are
+ # dropped from here on out.
+ #
+ self.send_and_assert_no_replies(self.tra_if, pkts)
+ seq_cycle_count += len(pkts)
+ self.assert_error_counter_equal(seq_cycle_node_name,
+ seq_cycle_count)
# move the security-associations seq number on to the last we used
self.vapi.cli("test ipsec sa %d seq 0x15f" % p.scapy_tra_sa_id)
@@ -423,6 +540,7 @@
def verify_tra_basic4(self, count=1):
""" ipsec v4 transport basic test """
self.vapi.cli("clear errors")
+ self.vapi.cli("clear ipsec sa")
try:
p = self.params[socket.AF_INET]
send_pkts = self.gen_encrypt_pkts(p.scapy_tra_sa, self.tra_if,
@@ -461,7 +579,7 @@
""" UT test methods for Transport v4 """
def test_tra_anti_replay(self):
""" ipsec v4 transport anti-reply test """
- self.verify_tra_anti_replay(count=1)
+ self.verify_tra_anti_replay()
def test_tra_basic(self, count=1):
""" ipsec v4 transport basic test """
diff --git a/test/test_ipsec_esp.py b/test/test_ipsec_esp.py
index 4da8891..f5bbc54 100644
--- a/test/test_ipsec_esp.py
+++ b/test/test_ipsec_esp.py
@@ -486,6 +486,14 @@
#
self.unconfig_network()
+ #
+ # reconfigure the network and SA to run the
+ # anti replay tests
+ #
+ self.config_network(self.params.values())
+ self.verify_tra_anti_replay()
+ self.unconfig_network()
+
if __name__ == '__main__':
unittest.main(testRunner=VppTestRunner)