Core/Misc: Check GetVictim() for NULL before dereferencing it

Add additional NULL checks all around the code before dereferencing GetVictim() result.
Keep in mind UpdateVictim() result has nothing to do with GetVictim() result and the caller shouldn't assume anything about GetVictim() based on UpdateVictim().

src/server/game/AI/CoreAI/CombatAI.cpp

@@ -151,7 +151,7 @@ void CasterAI::UpdateAI(uint32 diff)
 
     events.Update(diff);
 
-    if (me->EnsureVictim()->HasBreakableByDamageCrowdControlAura(me))
+    if (me->GetVictim() && me->EnsureVictim()->HasBreakableByDamageCrowdControlAura(me))
     {
         me->InterruptNonMeleeSpells(false);
         return;

src/server/scripts/EasternKingdoms/Karazhan/boss_prince_malchezaar.cpp

@@ -391,7 +391,7 @@ public:
             if (me->HasUnitState(UNIT_STATE_STUNNED))      // While shifting to phase 2 malchezaar stuns himself
                 return;
 
-            if (me->GetUInt64Value(UNIT_FIELD_TARGET) != me->EnsureVictim()->GetGUID())
+            if (me->GetVictim() && me->GetUInt64Value(UNIT_FIELD_TARGET) != me->EnsureVictim()->GetGUID())
                 me->SetTarget(me->EnsureVictim()->GetGUID());
 
             if (phase == 1)

src/server/scripts/EasternKingdoms/ScarletEnclave/chapter1.cpp

@@ -484,7 +484,7 @@ public:
                         EnterEvadeMode();
                     return;
                 }
-                else if (me->EnsureVictim()->GetTypeId() == TYPEID_PLAYER && me->EnsureVictim()->HealthBelowPct(10))
+                else if (me->GetVictim() && me->EnsureVictim()->GetTypeId() == TYPEID_PLAYER && me->EnsureVictim()->HealthBelowPct(10))
                 {
                     me->EnsureVictim()->CastSpell(me->GetVictim(), 7267, true); // beg
                     me->EnsureVictim()->RemoveGameObject(SPELL_DUEL_FLAG, true);
@@ -832,7 +832,7 @@ public:
                 }
             }
 
-            if (!UpdateVictim())
+            if (!UpdateVictim() || !me->GetVictim())
                 return;
 
             //ScriptedAI::UpdateAI(diff);

src/server/scripts/EasternKingdoms/SunwellPlateau/boss_kalecgos.cpp

@@ -298,7 +298,7 @@ public:
                         Unit* target = (*itr)->getTarget();
                         if (target
                                 && target->GetTypeId() == TYPEID_PLAYER
-                                && target->GetGUID() != me->EnsureVictim()->GetGUID()
+                                && (!target->GetVictim() || target->GetGUID() != me->EnsureVictim()->GetGUID())
                                 && target->GetPositionZ() > me->GetPositionZ() - 5
                                 && !target->HasAura(AURA_SPECTRAL_EXHAUSTION))
                         {

src/server/scripts/EasternKingdoms/ZulAman/boss_hexlord.cpp

@@ -887,7 +887,8 @@ class boss_fenstalker : public CreatureScript
                 if (volatileinf_timer <= diff)
                 {
                     // core bug
-                    me->EnsureVictim()->CastSpell(me->GetVictim(), SPELL_VOLATILE_INFECTION, false);
+                    if (me->GetVictim())
+                        me->EnsureVictim()->CastSpell(me->GetVictim(), SPELL_VOLATILE_INFECTION, false);
                     volatileinf_timer = 12000;
                 } else volatileinf_timer -= diff;
 

src/server/scripts/EasternKingdoms/ZulAman/boss_zuljin.cpp

@@ -428,7 +428,8 @@ class boss_zuljin : public CreatureScript
                         {
                             if (Unit* target = SelectTarget(SELECT_TARGET_RANDOM, 0))
                             {
-                                TankGUID = me->EnsureVictim()->GetGUID();
+                                if (me->GetVictim())
+                                    TankGUID = me->EnsureVictim()->GetGUID();
                                 me->SetSpeed(MOVE_RUN, 5.0f);
                                 AttackStart(target); // change victim
                                 Claw_Rage_Timer = 0;

src/server/scripts/Kalimdor/RuinsOfAhnQiraj/boss_ayamiss.cpp

@@ -156,9 +156,12 @@ class boss_ayamiss : public CreatureScript
                     _phase = PHASE_GROUND;
                     SetCombatMovement(true);
                     me->SetCanFly(false);
-                    Position VictimPos;
-                    me->EnsureVictim()->GetPosition(&VictimPos);
-                    me->GetMotionMaster()->MovePoint(POINT_GROUND, VictimPos);
+                    if (me->GetVictim())
+                    {
+                        Position VictimPos;
+                        me->EnsureVictim()->GetPosition(&VictimPos);
+                        me->GetMotionMaster()->MovePoint(POINT_GROUND, VictimPos);
+                    }
                     DoResetThreat();
                     events.ScheduleEvent(EVENT_LASH, urand(5000, 8000));
                     events.ScheduleEvent(EVENT_TRASH, urand(3000, 6000));

src/server/scripts/Kalimdor/TempleOfAhnQiraj/boss_viscidus.cpp

@@ -272,7 +272,8 @@ class npc_glob_of_viscidus : public CreatureScript
                     if (Viscidus->IsAlive() && Viscidus->GetHealthPct() < 5.0f)
                     {
                         Viscidus->SetVisible(true);
-                        Viscidus->EnsureVictim()->Kill(Viscidus);
+                        if (Viscidus->GetVictim())
+                            Viscidus->EnsureVictim()->Kill(Viscidus);
                     }
                     else
                     {

src/server/scripts/Kalimdor/zone_tanaris.cpp

@@ -123,7 +123,7 @@ public:
             {
                 if (SendItemTimer <= diff)
                 {
-                    if (me->EnsureVictim()->GetTypeId() == TYPEID_PLAYER)
+                    if (me->GetVictim() && me->EnsureVictim()->GetTypeId() == TYPEID_PLAYER)
                         SendItem(me->GetVictim());
                     SendItemTimer = 5000;
                 } else SendItemTimer -= diff;

src/server/scripts/Northrend/Nexus/Oculus/boss_urom.cpp

@@ -230,11 +230,14 @@ class boss_urom : public CreatureScript
                 {
                     if (arcaneExplosionTimer <= diff)
                     {
-                        Position pos;
-                        me->EnsureVictim()->GetPosition(&pos);
+                        if (me->GetVictim())
+                        {
+                            Position pos;
+                            me->EnsureVictim()->GetPosition(&pos);
 
-                        me->NearTeleportTo(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), pos.GetOrientation());
-                        me->GetMotionMaster()->MoveChase(me->GetVictim());
+                            me->NearTeleportTo(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), pos.GetOrientation());
+                            me->GetMotionMaster()->MoveChase(me->GetVictim());
+                        }
                         me->SetWalk(true);
 
                         Talk(EMOTE_ARCANE_EXPLOSION);

src/server/scripts/Northrend/Ulduar/Ulduar/boss_hodir.cpp

@@ -199,7 +199,10 @@ class npc_flash_freeze : public CreatureScript
 
             void UpdateAI(uint32 diff) OVERRIDE
             {
-                if (!UpdateVictim() || me->EnsureVictim()->HasAura(SPELL_BLOCK_OF_ICE) || me->EnsureVictim()->HasAura(SPELL_FLASH_FREEZE_HELPER))
+                if (!UpdateVictim()
+                 || !me->GetVictim()
+                 || me->EnsureVictim()->HasAura(SPELL_BLOCK_OF_ICE)
+                 || me->EnsureVictim()->HasAura(SPELL_FLASH_FREEZE_HELPER))
                     return;
 
                 if (me->EnsureVictim()->GetGUID() != targetGUID || instance->GetBossState(BOSS_HODIR) != IN_PROGRESS)

src/server/scripts/Outland/BlackTemple/boss_illidan.cpp

@@ -2074,7 +2074,7 @@ public:
 
         void UpdateAI(uint32 /*diff*/) OVERRIDE
         {
-            if (!UpdateVictim())
+            if (!UpdateVictim() || !me->GetVictim())
                 return;
 
             if (me->EnsureVictim()->GetTypeId() != TYPEID_PLAYER)

src/server/scripts/Outland/BlackTemple/boss_reliquary_of_souls.cpp

@@ -668,7 +668,7 @@ public:
         void UpdateAI(uint32 diff) OVERRIDE
         {
             //Return since we have no target
-            if (!UpdateVictim())
+            if (!UpdateVictim() || !me->GetVictim())
                 return;
 
             if (!CheckedAggro)

src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_fathomlord_karathress.cpp

@@ -626,7 +626,8 @@ public:
             {
                 DoCastVictim(SPELL_TIDAL_SURGE);
                 // Hacky way to do it - won't trigger elseways
-                me->EnsureVictim()->CastSpell(me->GetVictim(), SPELL_TIDAL_SURGE_FREEZE, true);
+                if (me->GetVictim())
+                    me->EnsureVictim()->CastSpell(me->GetVictim(), SPELL_TIDAL_SURGE_FREEZE, true);
                 TidalSurge_Timer = 15000+rand()%5000;
             } else TidalSurge_Timer -= diff;
 

src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_leotheras_the_blind.cpp

@@ -135,7 +135,7 @@ public:
         void UpdateAI(uint32 diff) OVERRIDE
         {
             //Return since we have no target
-            if (!UpdateVictim())
+            if (!UpdateVictim() || !me->GetVictim())
                 return;
 
             if (me->EnsureVictim()->GetGUID() != victimGUID)

src/server/scripts/Outland/TempestKeep/botanica/boss_warp_splinter.cpp

@@ -93,7 +93,7 @@ class npc_warp_splinter_treant : public CreatureScript
 
             void UpdateAI(uint32 diff) OVERRIDE
             {
-                if (!UpdateVictim())
+                if (!UpdateVictim() || !me->GetVictim())
                 {
                     if (WarpGuid && check_Timer <= diff)
                     {
@@ -115,7 +115,7 @@ class npc_warp_splinter_treant : public CreatureScript
                     return;
                 }
 
-                if (me->EnsureVictim()->GetGUID() !=  WarpGuid)
+                if (me->EnsureVictim()->GetGUID() != WarpGuid)
                     DoMeleeAttackIfReady();
             }
         };

src/server/scripts/Pet/pet_hunter.cpp

@@ -93,7 +93,7 @@ class npc_pet_hunter_snake_trap : public CreatureScript
 
             void UpdateAI(uint32 diff) OVERRIDE
             {
-                if (!UpdateVictim())
+                if (!UpdateVictim() || !me->GetVictim())
                     return;
 
                 if (me->EnsureVictim()->HasBreakableByDamageCrowdControlAura(me))