ikev2: do not require optional IDr on IKE AUTH

IDr is optional in IKE AUTH from the initiator. In that case, the
responder is free to use any matching profile and fills the
corresponding IDr in the response.
The initiator is then free to accept or reject it.

Type: improvement

Change-Id: I07a1c64a40ed22bd41767c259406238bbbab5cf4
Signed-off-by: Benoît Ganne <bganne@cisco.com>

2 files changed, 57 insertions, 20 deletions

diff --git a/src/plugins/ikev2/ikev2.c b/src/plugins/ikev2/ikev2.c
index 873ec136dae..c184a466c47 100644
--- a/src/plugins/ikev2/ikev2.c
+++ b/src/plugins/ikev2/ikev2.c
@@ -1050,7 +1050,7 @@ ikev2_decrypt_sk_payload (ikev2_sa_t * sa, ike_header_t * ike,
 }
 
 static int
-ikev2_is_id_equal (ikev2_id_t *i1, ikev2_id_t *i2)
+ikev2_is_id_equal (const ikev2_id_t *i1, const ikev2_id_t *i2)
 {
   if (i1->type != i2->type)
     return 0;
@@ -1572,6 +1572,25 @@ ikev2_sa_generate_authmsg (ikev2_sa_t * sa, int is_responder)
 }
 
 static int
+ikev2_match_profile (const ikev2_profile_t *p, const ikev2_id_t *id_loc,
+		     const ikev2_id_t *id_rem, int is_initiator)
+{
+  /* on the initiator, IDi is always present and must match
+   * however on the responder, IDr (which is our local id) is optional */
+  if ((is_initiator || id_loc->type != 0) &&
+      !ikev2_is_id_equal (&p->loc_id, id_loc))
+    return 0;
+
+  /* on the initiator, we might not have configured a specific remote id
+   * however on the responder, the remote id should always be configured */
+  if ((!is_initiator || p->rem_id.type != 0) &&
+      !ikev2_is_id_equal (&p->rem_id, id_rem))
+    return 0;
+
+  return 1;
+}
+
+static int
 ikev2_ts_cmp (ikev2_ts_t * ts1, ikev2_ts_t * ts2)
 {
   if (ts1->ts_type == ts2->ts_type && ts1->protocol_id == ts2->protocol_id &&
@@ -1609,9 +1628,7 @@ ikev2_sa_match_ts (ikev2_sa_t * sa)
         id_loc = &sa->r_id;
       }
 
-    /* check id */
-    if (!ikev2_is_id_equal (&p->rem_id, id_rem)
-          || !ikev2_is_id_equal (&p->loc_id, id_loc))
+    if (!ikev2_match_profile (p, id_loc, id_rem, sa->is_initiator))
       continue;
 
     sa->profile_index = p - km->profiles;
@@ -1679,9 +1696,7 @@ ikev2_select_profile (ikev2_main_t *km, ikev2_sa_t *sa,
 
   pool_foreach (p, km->profiles)
     {
-      /* check id */
-      if (!ikev2_is_id_equal (&p->rem_id, id_rem) ||
-	  !ikev2_is_id_equal (&p->loc_id, id_loc))
+      if (!ikev2_match_profile (p, id_loc, id_rem, sa->is_initiator))
 	continue;
 
       if (sa_auth->method == IKEV2_AUTH_METHOD_SHARED_KEY_MIC)
@@ -2444,7 +2459,10 @@ ikev2_generate_message (vlib_buffer_t *b, ikev2_sa_t *sa, ike_header_t *ike,
       else if (sa->state == IKEV2_STATE_SA_INIT)
 	{
 	  ikev2_payload_add_id (chain, &sa->i_id, IKEV2_PAYLOAD_IDI);
-	  ikev2_payload_add_id (chain, &sa->r_id, IKEV2_PAYLOAD_IDR);
+	  /* IDr is optional when sending INIT from the initiator */
+	  ASSERT (sa->r_id.type != 0 || sa->is_initiator);
+	  if (sa->r_id.type != 0)
+	    ikev2_payload_add_id (chain, &sa->r_id, IKEV2_PAYLOAD_IDR);
 	  ikev2_payload_add_auth (chain, &sa->i_auth);
 	  ikev2_payload_add_sa (chain, sa->childs[0].i_proposals);
 	  ikev2_payload_add_ts (chain, sa->childs[0].tsi, IKEV2_PAYLOAD_TSI);
diff --git a/test/test_ikev2.py b/test/test_ikev2.py
index 4f41ad272ba..438a674977f 100644
--- a/test/test_ikev2.py
+++ b/test/test_ikev2.py
@@ -802,9 +802,9 @@ class IkePeer(VppTestCase):
         self.assertEqual(sa.i_id.type, self.sa.id_type)
         self.assertEqual(sa.r_id.type, self.sa.id_type)
         self.assertEqual(sa.i_id.data_len, len(self.sa.i_id))
-        self.assertEqual(sa.r_id.data_len, len(self.sa.r_id))
+        self.assertEqual(sa.r_id.data_len, len(self.idr))
         self.assertEqual(bytes(sa.i_id.data, 'ascii'), self.sa.i_id)
-        self.assertEqual(bytes(sa.r_id.data, 'ascii'), self.sa.r_id)
+        self.assertEqual(bytes(sa.r_id.data, 'ascii'), self.idr)
 
         r = self.vapi.ikev2_child_sa_dump(sa_index=sa.sa_index)
         self.assertEqual(len(r), 1)
@@ -1003,9 +1003,12 @@ class TemplateInitiator(IkePeer):
         self.sa.msg_id += 1
         plain = self.sa.hmac_and_decrypt(ih)
         idi = ikev2.IKEv2_payload_IDi(plain)
-        idr = ikev2.IKEv2_payload_IDr(idi.payload)
         self.assertEqual(idi.load, self.sa.i_id)
-        self.assertEqual(idr.load, self.sa.r_id)
+        if self.no_idr_auth:
+            self.assertEqual(idi.next_payload, 39)  # AUTH
+        else:
+            idr = ikev2.IKEv2_payload_IDr(idi.payload)
+            self.assertEqual(idr.load, self.sa.r_id)
         prop = idi[ikev2.IKEv2_payload_Proposal]
         c = self.sa.child_sas[0]
         c.ispi = prop.SPI
@@ -1264,10 +1267,15 @@ class TemplateResponder(IkePeer):
                      proto='ESP', SPI=c.ispi))
         else:
             first_payload = 'IDi'
-            ids = (ikev2.IKEv2_payload_IDi(next_payload='IDr',
-                   IDtype=self.sa.id_type, load=self.sa.i_id) /
-                   ikev2.IKEv2_payload_IDr(next_payload='AUTH',
-                   IDtype=self.sa.id_type, load=self.sa.r_id))
+            if self.no_idr_auth:
+                ids = ikev2.IKEv2_payload_IDi(next_payload='AUTH',
+                                              IDtype=self.sa.id_type,
+                                              load=self.sa.i_id)
+            else:
+                ids = (ikev2.IKEv2_payload_IDi(next_payload='IDr',
+                       IDtype=self.sa.id_type, load=self.sa.i_id) /
+                       ikev2.IKEv2_payload_IDr(next_payload='AUTH',
+                       IDtype=self.sa.id_type, load=self.sa.r_id))
             plain = ids / plain
         return plain, first_payload
 
@@ -1394,15 +1402,23 @@ class Ikev2Params(object):
 
         is_init = True if 'is_initiator' not in params else\
             params['is_initiator']
+        self.no_idr_auth = params.get('no_idr_in_auth', False)
 
         idr = {'id_type': 'fqdn', 'data': b'vpp.home'}
         idi = {'id_type': 'fqdn', 'data': b'roadwarrior.example.com'}
+        r_id = self.idr = idr['data']
+        i_id = self.idi = idi['data']
         if is_init:
+            # scapy is initiator, VPP is responder
             self.p.add_local_id(**idr)
             self.p.add_remote_id(**idi)
+            if self.no_idr_auth:
+                r_id = None
         else:
+            # VPP is initiator, scapy is responder
             self.p.add_local_id(**idi)
-            self.p.add_remote_id(**idr)
+            if not self.no_idr_auth:
+                self.p.add_remote_id(**idr)
 
         loc_ts = {'start_addr': '10.10.10.0', 'end_addr': '10.10.10.255'} if\
             'loc_ts' not in params else params['loc_ts']
@@ -1436,7 +1452,7 @@ class Ikev2Params(object):
                                                self.pg0.remote_ip4)
             self.vapi.cli(cmd)
 
-        self.sa = IKEv2SA(self, i_id=idi['data'], r_id=idr['data'],
+        self.sa = IKEv2SA(self, i_id=i_id, r_id=r_id,
                           is_initiator=is_init,
                           id_type=self.p.local_id['id_type'],
                           i_natt=i_natt, r_natt=r_natt,
@@ -1444,6 +1460,7 @@ class Ikev2Params(object):
                           nonce=params.get('nonce'),
                           auth_data=auth_data, udp_encap=udp_encap,
                           local_ts=self.p.remote_ts, remote_ts=self.p.local_ts)
+
         if is_init:
             ike_crypto = ('AES-CBC', 32) if 'ike-crypto' not in params else\
                 params['ike-crypto']
@@ -1818,7 +1835,8 @@ class TestInitiatorDelSAFromResponder(TemplateInitiator, Ikev2Params):
                 'crypto_alg': 12,  # "aes-cbc"
                 'crypto_key_size': 256,
                 # "hmac-sha2-256-128"
-                'integ_alg': 12}})
+                'integ_alg': 12},
+            'no_idr_in_auth': True})
 
 
 @tag_fixme_vpp_workers
@@ -1957,7 +1975,8 @@ class Test_IKE_AES_CBC_128_SHA256_128_MODP2048_ESP_AES_CBC_192_SHA_384_192\
             'esp-crypto': ('AES-CBC', 24),
             'esp-integ': 'SHA2-384-192',
             'ike-dh': '2048MODPgr',
-            'nonce': os.urandom(256)})
+            'nonce': os.urandom(256),
+            'no_idr_in_auth': True})
 
 
 @tag_fixme_vpp_workers