Core/Spells: Fully prevent infinite proc loops and add logging to detect most spells that could possibly trigger this behavior at startup

src/server/game/Entities/Unit/Unit.cpp

@@ -301,7 +301,7 @@ bool DispelableAura::RollDispel() const
 Unit::Unit(bool isWorldObject) :
     WorldObject(isWorldObject),  m_lastSanctuaryTime(0),
     LastCharmerGUID(), m_ControlledByPlayer(false), movespline(std::make_unique<Movement::MoveSpline>()),
-    m_procDeep(0),  m_removedAurasCount(0),
+    m_procDeep(0), m_procChainLength(0), m_removedAurasCount(0),
     m_interruptMask(SpellAuraInterruptFlags::None), m_interruptMask2(SpellAuraInterruptFlags2::None),
     m_charmer(nullptr), m_charmed(nullptr),
     i_motionMaster(std::make_unique<MotionMaster>(this)), m_vehicle(nullptr),
@@ -5108,6 +5108,13 @@ void Unit::SendSpellNonMeleeDamageLog(Unit* target, uint32 spellID, uint32 damag
 /*static*/ void Unit::ProcSkillsAndAuras(Unit* actor, Unit* actionTarget, ProcFlags typeMaskActor, ProcFlags typeMaskActionTarget,
     ProcFlagsSpellType spellTypeMask, ProcFlagsSpellPhase spellPhaseMask, ProcFlagsHit hitMask, Spell* spell, DamageInfo* damageInfo, HealInfo* healInfo)
 {
+    static constexpr int32 ProcChainHardLimit = 10;
+    if (spell && spell->GetProcChainLength() >= ProcChainHardLimit)
+    {
+        TC_LOG_ERROR("spells.aura.effect", "Unit::ProcSkillsAndAuras: Possible infinite proc loop detected, current triggering spell %u", spell->GetSpellInfo()->Id);
+        return;
+    }
+
     WeaponAttackType attType = damageInfo ? damageInfo->GetAttackType() : BASE_ATTACK;
     SpellInfo const* spellInfo = [&]() -> SpellInfo const*
     {

src/server/game/Entities/Unit/Unit.h

@@ -1560,6 +1560,7 @@ class TC_GAME_API Unit : public WorldObject
         // proc trigger system
         bool CanProc() const { return !m_procDeep; }
         void SetCantProc(bool apply);
+        int32 GetProcChainLength() const { return m_procChainLength; }
 
         uint32 GetModelForForm(ShapeshiftForm form, uint32 spellId) const;
         uint32 GetModelForTotem(PlayerTotemType totemType);
@@ -1671,7 +1672,9 @@ class TC_GAME_API Unit : public WorldObject
 
         DeathState m_deathState;
 
-        int32 m_procDeep;
+        int32 m_procDeep;               // tracked for proc system correctness (what spells should proc what)
+        int32 m_procChainLength;        // tracked to protect against infinite proc loops (hard limit, will disallow procs even if they should happen)
+
 
         typedef std::list<DynamicObject*> DynObjectList;
         DynObjectList m_dynObj;

src/server/game/Spells/Spell.cpp

@@ -656,6 +656,7 @@ m_caster((info->HasAttribute(SPELL_ATTR6_ORIGINATE_FROM_CONTROLLER) && caster->G
     m_cast_count = 0;
     m_glyphIndex = 0;
     m_triggeredByAuraSpell  = nullptr;
+    m_procChainLength = caster->IsUnit() ? caster->ToUnit()->GetProcChainLength() : 0;
     unitCaster = nullptr;
     _spellAura = nullptr;
     _dynObjAura = nullptr;

src/server/game/Spells/Spell.h

@@ -454,6 +454,8 @@ class TC_GAME_API Spell
 
         bool IsTriggeredByAura(SpellInfo const* auraSpellInfo) const { return (auraSpellInfo == m_triggeredByAuraSpell); }
 
+        int32 GetProcChainLength() const { return m_procChainLength; }
+
         bool IsDeletable() const { return !m_referencedFromCurrentSpell && !m_executedCurrently; }
         void SetReferencedFromCurrent(bool yes) { m_referencedFromCurrentSpell = yes; }
         bool IsInterruptable() const { return !m_executedCurrently; }
@@ -725,6 +727,7 @@ class TC_GAME_API Spell
         // we can't store original aura link to prevent access to deleted auras
         // and in same time need aura data and after aura deleting.
         SpellInfo const* m_triggeredByAuraSpell;
+        int32 m_procChainLength;
 
         uint8 m_auraScaleMask;
         std::unique_ptr<PathGenerator> m_preGeneratedPath;

src/server/game/Spells/SpellMgr.cpp

@@ -1856,6 +1856,7 @@ void SpellMgr::LoadSpellProcs()
         procEntry.SpellPhaseMask  = PROC_SPELL_PHASE_HIT;
         procEntry.HitMask         = PROC_HIT_NONE; // uses default proc @see SpellMgr::CanSpellTriggerProcOnEvent
 
+        bool triggersSpell = false;
         for (uint32 i = 0; i < MAX_SPELL_EFFECTS; ++i)
         {
             if (!spellInfo->Effects[i].IsAura())
@@ -1881,6 +1882,10 @@ void SpellMgr::LoadSpellProcs()
                     if (spellInfo->Effects[i].CalcValue() <= -100)
                         procEntry.HitMask = PROC_HIT_MISS;
                     break;
+                case SPELL_AURA_PROC_TRIGGER_SPELL:
+                case SPELL_AURA_PROC_TRIGGER_SPELL_WITH_VALUE:
+                    triggersSpell = spellInfo->Effects[i].TriggerSpell != 0;
+                    break;
                 default:
                     continue;
             }
@@ -1899,6 +1904,22 @@ void SpellMgr::LoadSpellProcs()
         procEntry.Cooldown        = Milliseconds::zero();
         procEntry.Charges         = spellInfo->ProcCharges;
 
+        if (spellInfo->HasAttribute(SPELL_ATTR3_CAN_PROC_FROM_PROCS) && !procEntry.SpellFamilyMask
+            && procEntry.Chance >= 100
+            && procEntry.ProcsPerMinute <= 0.0f
+            && procEntry.Cooldown <= 0ms
+            && procEntry.Charges <= 0
+            && procEntry.ProcFlags & (PROC_FLAG_DEAL_MELEE_ABILITY | PROC_FLAG_DEAL_RANGED_ATTACK | PROC_FLAG_DEAL_RANGED_ABILITY | PROC_FLAG_DEAL_HELPFUL_ABILITY
+                | PROC_FLAG_DEAL_HARMFUL_ABILITY | PROC_FLAG_DEAL_HELPFUL_SPELL | PROC_FLAG_DEAL_HARMFUL_SPELL | PROC_FLAG_MAIN_HAND_WEAPON_SWING
+                | PROC_FLAG_OFF_HAND_WEAPON_SWING)
+            && triggersSpell)
+        {
+            TC_LOG_ERROR("sql.sql", "Spell Id %u has SPELL_ATTR3_CAN_PROC_FROM_PROCS attribute and no restriction on what spells can cause it to proc and no cooldown. "
+                "This spell can cause infinite proc loops. Proc data for this spell was not generated, data in `spell_proc` table is required for it to function!",
+                spellInfo->Id);
+            continue;
+        }
+
         mSpellProcMap[spellInfo->Id] = procEntry;
         ++count;
     }