Validate ranged targets server-side

src/game/input_main.cpp

@@ -2092,6 +2092,49 @@ int CInputMain::SyncPosition(LPCHARACTER ch, const char * c_pcData, size_t uiByt
 void CInputMain::FlyTarget(LPCHARACTER ch, const char * pcData, uint16_t wHeader)
 {
 	TPacketCGFlyTargeting * p = (TPacketCGFlyTargeting *) pcData;
+
+	if (ch && ch->IsPC())
+	{
+		LPCHARACTER victim = CHARACTER_MANAGER::instance().Find(p->dwTargetVID);
+
+		if (!victim)
+		{
+			sys_log(1, "FLY_TARGET_INVALID: %s target=%u missing", ch->GetName(), p->dwTargetVID);
+			return;
+		}
+
+		if (ch == victim)
+		{
+			char szDetail[128];
+			snprintf(szDetail, sizeof(szDetail), "target=%u x=%ld y=%ld", p->dwTargetVID, static_cast<long>(p->x), static_cast<long>(p->y));
+			ch->RecordAntiCheatViolation("FLY_TARGET_INVALID", 4, szDetail);
+			return;
+		}
+
+		switch (victim->GetCharType())
+		{
+			case CHAR_TYPE_WARP:
+			case CHAR_TYPE_GOTO:
+				ch->RecordAntiCheatViolation("FLY_TARGET_INVALID", 6, victim->GetName(), true);
+				return;
+		}
+
+		int distance = 0;
+		int maxDistance = 0;
+		if (!battle_ranged_target_valid(ch, victim, 0, &distance, &maxDistance))
+		{
+			char szDetail[160];
+			snprintf(szDetail,
+				 sizeof(szDetail),
+				 "target=%s distance=%d max=%d",
+				 victim->GetName(),
+				 distance,
+				 maxDistance);
+			ch->RecordAntiCheatViolation("FLY_TARGET_RANGE", distance > maxDistance + 800 ? 12 : 4, szDetail, distance > maxDistance + 800);
+			return;
+		}
+	}
+
 	ch->FlyTarget(p->dwTargetVID, p->x, p->y, wHeader);
 }