From bcf9476e9600af1abe1558c85463483c8ff8f8ea Mon Sep 17 00:00:00 2001
From: Ovahlord <dreadkiller@gmx.de>
Date: Fri, 19 Feb 2021 18:31:45 +0100
Subject: [PATCH] Core/Spells: restored accidentally dropped spell cast target
 limit to fix client crashes when hitting more than 255 targets with a single
 spell

---
 src/server/game/Server/Packets/SpellPackets.cpp | 14 ++++++++++++++
 src/server/game/Server/Packets/SpellPackets.h   |  2 +-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/server/game/Server/Packets/SpellPackets.cpp b/src/server/game/Server/Packets/SpellPackets.cpp
index c4570565662..b57ef1d2580 100644
--- a/src/server/game/Server/Packets/SpellPackets.cpp
+++ b/src/server/game/Server/Packets/SpellPackets.cpp
@@ -121,7 +121,21 @@ ByteBuffer& operator<<(ByteBuffer& data, WorldPackets::Spells::SpellCastData con
     data << uint32(spellCastData.CastTime);
 
     if (spellCastData.HitInfo)
+    {
+        // Hit and miss target counts are both uint8, that limits us to 255 targets for each
+        // sending more than 255 targets crashes the client (since count sent would be wrong)
+        // Spells like 40647 (with a huge radius) can easily reach this limit (spell might need
+        // target conditions but we still need to limit the number of targets sent and keeping
+        // correct count for both hit and miss).
+        static std::size_t const PACKET_TARGET_LIMIT = std::numeric_limits<uint8>::max();
+        if (spellCastData.HitInfo->HitTargets.size() > PACKET_TARGET_LIMIT)
+            spellCastData.HitInfo->HitTargets.resize(PACKET_TARGET_LIMIT);
+
+        if (spellCastData.HitInfo->MissStatus.size() > PACKET_TARGET_LIMIT)
+            spellCastData.HitInfo->MissStatus.resize(PACKET_TARGET_LIMIT);
+
         data << *spellCastData.HitInfo;
+    }
 
     data << spellCastData.Target;
 
diff --git a/src/server/game/Server/Packets/SpellPackets.h b/src/server/game/Server/Packets/SpellPackets.h
index 56d65be4eca..178f2643c73 100644
--- a/src/server/game/Server/Packets/SpellPackets.h
+++ b/src/server/game/Server/Packets/SpellPackets.h
@@ -109,7 +109,7 @@ namespace WorldPackets
             uint32 CastFlagsEx = 0;
             uint32 CastTime = 0;
             SpellTargetData Target;
-            Optional<SpellHitInfo> HitInfo;
+            mutable Optional<SpellHitInfo> HitInfo;
             Optional<uint8> DestLocSpellCastIndex;
             Optional<SpellHealPrediction> Predict;
             Optional<CreatureImmunities> Immunities;