ISAKMP: fix dissection of IKEv2 ID Payload

Fix dissection of the IKEv2 Identification Payload.
Unlike IKEv1, it does not have Protocol and Port fields.

References:
* RFC 2407, section 4.6.2
* RFC 7296, section 3.5

Change-Id: I968e378abd49363785dd7308a4f27908c1c05a8a
Reviewed-on: https://code.wireshark.org/review/19497
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>

1 files changed, 22 insertions, 16 deletions

diff --git a/epan/dissectors/packet-isakmp.c b/epan/dissectors/packet-isakmp.c
index 432cd89b6f..e1a0c66e22 100644
--- a/epan/dissectors/packet-isakmp.c
+++ b/epan/dissectors/packet-isakmp.c
@@ -4086,26 +4086,32 @@ dissect_id(tvbuff_t *tvb, int offset, int length, proto_tree *tree, int isakmp_v
   offset += 1;
   length -= 1;
 
-  protocol_id= tvb_get_guint8(tvb, offset);
-  if (protocol_id == 0)
-    proto_tree_add_uint_format_value(tree, hf_isakmp_id_protoid, tvb, offset,1,
-                               protocol_id, "Unused");
-  else
-    proto_tree_add_item(tree, hf_isakmp_id_protoid, tvb, offset, 1, ENC_BIG_ENDIAN);
+  if (isakmp_version == 1) {
+    protocol_id = tvb_get_guint8(tvb, offset);
+    if (protocol_id == 0)
+      proto_tree_add_uint_format_value(tree, hf_isakmp_id_protoid, tvb, offset, 1,
+                                 protocol_id, "Unused");
+    else
+      proto_tree_add_item(tree, hf_isakmp_id_protoid, tvb, offset, 1, ENC_BIG_ENDIAN);
 
-  offset += 1;
-  length -= 1;
+    offset += 1;
+    length -= 1;
 
-  port = tvb_get_ntohs(tvb, offset);
-  if (port == 0)
-    proto_tree_add_uint_format_value(tree, hf_isakmp_id_port, tvb, offset, 2,
-                               port, "Unused");
-  else
-    proto_tree_add_item(tree, hf_isakmp_id_port, tvb, offset, 2, ENC_BIG_ENDIAN);
+    port = tvb_get_ntohs(tvb, offset);
+    if (port == 0)
+      proto_tree_add_uint_format_value(tree, hf_isakmp_id_port, tvb, offset, 2,
+                                 port, "Unused");
+    else
+      proto_tree_add_item(tree, hf_isakmp_id_port, tvb, offset, 2, ENC_BIG_ENDIAN);
 
-  offset += 2;
-  length -= 2;
+    offset += 2;
+    length -= 2;
 
+  } else if (isakmp_version == 2) {
+    /* Reserved */
+    offset += 3;
+    length -= 3;
+  }
 
   /*
    * It shows strings of all types though some of types are not