Add some logging for suspicious HitMessages (#459)

* Add some logging for suspicious HitMessages

* Add HitPositionDiscrepancyThreshold config settings

* Add hit position discrepancy check to LashMessage & SplashHitMessage

* Whitespace

common/src/main/scala/net/psforever/packet/game/LashMessage.scala

@@ -12,14 +12,14 @@ import scodec.codecs._
   * @param player na
   * @param victim na
   * @param bullet na
-  * @param pos na
+  * @param hit_pos na
   * @param unk1 na
   */
 final case class LashMessage(seq_time : Int,
                              player : PlanetSideGUID,
                              victim : PlanetSideGUID,
                              bullet : PlanetSideGUID,
-                             pos : Vector3,
+                             hit_pos : Vector3,
                              unk1 : Int)
   extends PlanetSideGamePacket {
   type Packet = LashMessage
@@ -33,7 +33,7 @@ object LashMessage extends Marshallable[LashMessage] {
       ("player" | PlanetSideGUID.codec) ::
       ("victim" | PlanetSideGUID.codec) ::
       ("bullet" | PlanetSideGUID.codec) ::
-      ("pos" | Vector3.codec_pos) ::
+      ("hit_pos" | Vector3.codec_pos) ::
       ("unk1" | uintL(3))
     ).as[LashMessage]
 }

config/worldserver.ini.dist

@@ -248,3 +248,12 @@ NetSim.ReorderTime = 150 milliseconds
 #                     yes - (Enabled)
 
 Active = no
+
+[antihack]
+
+#    HitPositionDiscrepancyThreshold (int)
+#        Description: The distance (squared) threshold that triggers if the reported hit location of a shot does not match the object being hit's location on the server
+#        Range:       [1, 1000000]
+#        Default:     10000 (sqrt 10000 = ~100 ingame units)
+
+HitPositionDiscrepancyThreshold = 10000

pslogin/src/main/scala/WorldConfig.scala

@@ -45,6 +45,9 @@ object WorldConfig extends ConfigParser {
     ),
     ConfigSection("kamon",
       ConfigEntryBool("Active", false)
+    ),
+    ConfigSection("antihack",
+      ConfigEntryInt("HitPositionDiscrepancyThreshold", 10000, Constraints.min(1), Constraints.max(1000000))
     )
   )
 

pslogin/src/main/scala/WorldSessionActor.scala

@@ -5,7 +5,10 @@ import com.github.mauricio.async.db.general.ArrayRowData
 import com.github.mauricio.async.db.{Connection, QueryResult}
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicInteger
+
+import net.psforever.WorldConfig
 import org.log4s.{Logger, MDC}
+
 import scala.annotation.{switch, tailrec}
 import scala.collection.mutable.LongMap
 import scala.concurrent.{Await, Future, Promise}
@@ -6213,6 +6216,7 @@ class WorldSessionActor extends Actor
         case Some(hitInfo) =>
           ValidObject(hitInfo.hitobject_guid) match {
             case Some(target : PlanetSideGameObject with FactionAffinity with Vitality) =>
+              CheckForHitPositionDiscrepancy(projectile_guid, hitInfo.hit_pos, target)
               Some((target, hitInfo.shot_origin, hitInfo.hit_pos))
             case _ =>
               None
@@ -6238,6 +6242,7 @@ class WorldSessionActor extends Actor
           //direct_victim_uid
           ValidObject(direct_victim_uid) match {
             case Some(target : PlanetSideGameObject with FactionAffinity with Vitality) =>
+              CheckForHitPositionDiscrepancy(projectile_guid, explosion_pos, target)
               ResolveProjectileEntry(projectile, ProjectileResolution.Splash, target, target.Position) match {
                 case Some(projectile) =>
                   HandleDealingDamage(target, projectile)
@@ -6249,6 +6254,7 @@ class WorldSessionActor extends Actor
           targets.foreach(elem => {
             ValidObject(elem.uid) match {
               case Some(target : PlanetSideGameObject with FactionAffinity with Vitality) =>
+                CheckForHitPositionDiscrepancy(projectile_guid, explosion_pos, target)
                 ResolveProjectileEntry(projectile, ProjectileResolution.Splash, target, explosion_pos) match {
                   case Some(projectile) =>
                     HandleDealingDamage(target, projectile)
@@ -6270,11 +6276,12 @@ class WorldSessionActor extends Actor
         case None => ;
       }
 
-    case msg @ LashMessage(seq_time, killer_guid, victim_guid, projectile_guid, pos, unk1) =>
+    case msg @ LashMessage(seq_time, killer_guid, victim_guid, projectile_guid, hit_pos, unk1) =>
       log.info(s"Lash: $msg")
       ValidObject(victim_guid) match {
         case Some(target : PlanetSideGameObject with FactionAffinity with Vitality) =>
-          ResolveProjectileEntry(projectile_guid, ProjectileResolution.Lash, target, pos) match {
+          CheckForHitPositionDiscrepancy(projectile_guid, hit_pos, target)
+          ResolveProjectileEntry(projectile_guid, ProjectileResolution.Lash, target, hit_pos) match {
             case Some(projectile) =>
               HandleDealingDamage(target, projectile)
             case None => ;
@@ -11397,6 +11404,14 @@ class WorldSessionActor extends Actor
     }
   }
 
+  def CheckForHitPositionDiscrepancy(projectile_guid: PlanetSideGUID, hitPos : Vector3, target : PlanetSideGameObject with FactionAffinity with Vitality): Unit = {
+    val hitPositionDiscrepancy = Vector3.DistanceSquared(hitPos, target.Position)
+    if(hitPositionDiscrepancy > WorldConfig.Get[Int]("antihack.HitPositionDiscrepancyThreshold")) {
+      // If the target position on the server does not match the position where the projectile landed within reason there may be foul play
+      log.warn(s"Shot guid ${projectile_guid} has hit location discrepancy with target location. Target: ${target.Position} Reported: ${hitPos}, Distance: ${hitPositionDiscrepancy} / ${math.sqrt(hitPositionDiscrepancy).toFloat}; suspect")
+    }
+  }
+
   def failWithError(error : String) = {
     log.error(error)
     sendResponse(ConnectionClose())