[9388] Implement max cast chain length for triggered spells.

* New config option MaxSpellCastsInChain ( 0 is disabled old way work )
* Check added for prevent stack overflow crashes in case infinity triggered casts sequences
  with more useful error output instead crash.
* Default config steeing in 10 casts expected to allow all possible in game proper cast chains.

src/game/Spell.cpp

@@ -2522,6 +2522,19 @@ void Spell::cast(bool skipCheck)
 {
     SetExecutedCurrently(true);
 
+    if (!m_caster->CheckAndIncreaseCastCounter())
+    {
+        if (m_triggeredByAuraSpell)
+            sLog.outError("Spell %u triggered by aura spell %u too deep in cast chain for cast. Cast not allowed for prevent overflow stack crash.");
+        else
+            sLog.outError("Spell %u too deep in cast chain for cast. Cast not allowed for prevent overflow stack crash.");
+
+        SendCastResult(SPELL_FAILED_ERROR);
+        finish(false);
+        SetExecutedCurrently(false);
+        return;
+    }
+
     // update pointers base at GUIDs to prevent access to non-existed already object
     UpdatePointers();
 
@@ -2529,6 +2542,7 @@ void Spell::cast(bool skipCheck)
     if(!m_targets.getUnitTarget() && m_targets.getUnitTargetGUID() && m_targets.getUnitTargetGUID() != m_caster->GetGUID())
     {
         cancel();
+        m_caster->DecreaseCastCounter();
         SetExecutedCurrently(false);
         return;
     }
@@ -2541,6 +2555,7 @@ void Spell::cast(bool skipCheck)
     {
         SendCastResult(castResult);
         finish(false);
+        m_caster->DecreaseCastCounter();
         SetExecutedCurrently(false);
         return;
     }
@@ -2553,6 +2568,7 @@ void Spell::cast(bool skipCheck)
         {
             SendCastResult(castResult);
             finish(false);
+            m_caster->DecreaseCastCounter();
             SetExecutedCurrently(false);
             return;
         }
@@ -2667,6 +2683,7 @@ void Spell::cast(bool skipCheck)
 
     if(m_spellState == SPELL_STATE_FINISHED)                // stop cast if spell marked as finish somewhere in FillTargetMap
     {
+        m_caster->DecreaseCastCounter();
         SetExecutedCurrently(false);
         return;
     }
@@ -2699,6 +2716,7 @@ void Spell::cast(bool skipCheck)
         handle_immediate();
     }
 
+    m_caster->DecreaseCastCounter();
     SetExecutedCurrently(false);
 }
 

src/game/Unit.cpp

@@ -208,6 +208,8 @@ Unit::Unit()
     for (uint32 i = 0; i < CURRENT_MAX_SPELL; ++i)
         m_currentSpells[i] = NULL;
 
+    m_castCounter = 0;
+
     m_addDmgOnce = 0;
 
     for(int i = 0; i < MAX_TOTEM; ++i)
@@ -13435,3 +13437,14 @@ void Unit::CleanupDeletedAuras()
         delete *itr;
     m_deletedAuras.clear();
 }
+
+bool Unit::CheckAndIncreaseCastCounter()
+{
+    uint32 maxCasts = sWorld.getConfig(CONFIG_MAX_SPELL_CASTS_IN_CHAIN);
+
+    if (maxCasts && m_castCounter >= maxCasts)
+        return false;
+
+    ++m_castCounter;
+    return true;
+}

src/game/Unit.h

@@ -1520,6 +1520,9 @@ class MANGOS_DLL_SPEC Unit : public WorldObject
         Spell* GetCurrentSpell(CurrentSpellTypes spellType) const { return m_currentSpells[spellType]; }
         Spell* FindCurrentSpellBySpellId(uint32 spell_id) const;
 
+        bool CheckAndIncreaseCastCounter();
+        void DecreaseCastCounter() { if (m_castCounter) --m_castCounter; }
+
         uint32 m_addDmgOnce;
         uint64 m_TotemSlot[MAX_TOTEM];
         uint64 m_ObjectSlot[4];
@@ -1848,6 +1851,7 @@ class MANGOS_DLL_SPEC Unit : public WorldObject
         uint32 m_CombatTimer;
 
         Spell* m_currentSpells[CURRENT_MAX_SPELL];
+        uint32 m_castCounter;                               // count casts chain of triggered spells for prevent infinity cast crashes
 
         UnitVisibility m_Visibility;
 

src/game/World.cpp

@@ -795,6 +795,8 @@ void World::LoadConfigSettings(bool reload)
     m_configs[CONFIG_INSTANCE_IGNORE_RAID]  = sConfig.GetBoolDefault("Instance.IgnoreRaid", false);
 
     m_configs[CONFIG_CAST_UNSTUCK] = sConfig.GetBoolDefault("CastUnstuck", true);
+    m_configs[CONFIG_MAX_SPELL_CASTS_IN_CHAIN] = sConfig.GetIntDefault("MaxSpellCastsInChain", 10);
+
     m_configs[CONFIG_INSTANCE_RESET_TIME_HOUR]  = sConfig.GetIntDefault("Instance.ResetTimeHour", 4);
     m_configs[CONFIG_INSTANCE_UNLOAD_DELAY] = sConfig.GetIntDefault("Instance.UnloadDelay", 30 * MINUTE * IN_MILISECONDS);
 

src/game/World.h

@@ -127,6 +127,7 @@ enum WorldConfigs
     CONFIG_INSTANCE_RESET_TIME_HOUR,
     CONFIG_INSTANCE_UNLOAD_DELAY,
     CONFIG_CAST_UNSTUCK,
+    CONFIG_MAX_SPELL_CASTS_IN_CHAIN,
     CONFIG_MAX_PRIMARY_TRADE_SKILL,
     CONFIG_MIN_PETITION_SIGNS,
     CONFIG_GM_LOGIN_STATE,

src/mangosd/mangosd.conf.dist.in

@@ -508,6 +508,12 @@ LogColors = ""
 #        Default: 1 (true)
 #                 0 (false)
 #
+#    MaxSpellCastsInChain
+#        Max amount triggered spell casts in chain by one caster, prevent stack overflow crash
+#        Too Low value will make some correct triggered casts fail
+#                 0 (no limit)
+#        Default: 10
+#
 #    Instance.IgnoreLevel
 #        Ignore level requirement to enter instance
 #        Default: 0 (false)

src/shared/revision_nr.h

@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "9387"
+ #define REVISION_NR "9388"
 #endif // __REVISION_NR_H__