From 62a17274ff5a8b9bac24a0715645b213daa69956 Mon Sep 17 00:00:00 2001
From: Wickedness <y2keui@nate.com>
Date: Sun, 5 Jul 2026 12:58:16 +0900
Subject: [PATCH] Harden battle save growth validation

---
 scripts/verify-battle-save-normalization.mjs |  5 ++++
 src/game/state/battleSaveState.ts            | 26 ++++++++++++++++----
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/scripts/verify-battle-save-normalization.mjs b/scripts/verify-battle-save-normalization.mjs
index 9d873c0..2bfe0a3 100644
--- a/scripts/verify-battle-save-normalization.mjs
+++ b/scripts/verify-battle-save-normalization.mjs
@@ -54,6 +54,8 @@ try {
     ['unknown attack intent unit id', { attackIntents: [{ attackerId: 'liu-bei', targetId: 'ghost-unit' }] }],
     ['duplicate attack intent attacker id', { attackIntents: [{ attackerId: 'liu-bei', targetId: 'rebel-1' }, { attackerId: 'liu-bei', targetId: 'rebel-1' }] }],
     ['invalid units array', { units: {} }],
+    ['invalid unit exp threshold', { units: patchUnit(0, { exp: 100 }) }],
+    ['invalid max-level unit exp threshold', { units: patchUnit(0, { level: 99, exp: 101 }) }],
     ['invalid unit hp', { units: patchUnit(0, { hp: 99, maxHp: 30 }) }],
     ['invalid unit x', { units: patchUnit(0, { x: 12 }) }],
     ['invalid unit direction', { units: patchUnit(0, { direction: 'down' }) }],
@@ -62,7 +64,10 @@ try {
     ['unknown equipment item id', { units: patchUnit(0, { equipment: { ...createEquipmentSet(), weapon: { itemId: 'phantom-sword', level: 1, exp: 0 } } }) }],
     ['wrong equipment slot item id', { units: patchUnit(0, { equipment: { ...createEquipmentSet(), weapon: { itemId: 'cloth-armor', level: 1, exp: 0 } } }) }],
     ['invalid equipment level', { units: patchUnit(0, { equipment: { ...createEquipmentSet(), weapon: { itemId: 'training-sword', level: 0, exp: 0 } } }) }],
+    ['too high equipment level', { units: patchUnit(0, { equipment: { ...createEquipmentSet(), weapon: { itemId: 'training-sword', level: 10, exp: 0 } } }) }],
     ['invalid equipment exp', { units: patchUnit(0, { equipment: { ...createEquipmentSet(), weapon: { itemId: 'training-sword', level: 1, exp: -1 } } }) }],
+    ['invalid equipment exp threshold', { units: patchUnit(0, { equipment: { ...createEquipmentSet(), weapon: { itemId: 'training-sword', level: 1, exp: 70 } } }) }],
+    ['invalid max-level equipment exp threshold', { units: patchUnit(0, { equipment: { ...createEquipmentSet(), weapon: { itemId: 'training-sword', level: 9, exp: 231 } } }) }],
     ['unknown unit id', { units: patchUnit(0, { id: 'ghost-unit' }) }],
     ['duplicate unit id', { units: [validState.units[0], { ...validState.units[0], x: 2 }, validState.units[2]] }],
     ['invalid bonds', { bonds: [{ ...validState.bonds[0], unitIds: ['liu-bei'] }] }],
diff --git a/src/game/state/battleSaveState.ts b/src/game/state/battleSaveState.ts
index b258ec2..ea2f6ff 100644
--- a/src/game/state/battleSaveState.ts
+++ b/src/game/state/battleSaveState.ts
@@ -1,7 +1,7 @@
 import type { BattleBond, UnitData } from '../data/scenario';
 import type { CampaignStep } from './campaignState';
 import type { UnitDirection } from '../data/unitAssets';
-import { equipmentSlots, type EquipmentSlot } from '../data/battleItems';
+import { equipmentExpToNext, equipmentSlots, type EquipmentSlot } from '../data/battleItems';
 
 export type BattleSaveFaction = 'ally' | 'enemy';
 export type BattleSaveRosterTab = 'ally' | 'enemy';
@@ -239,8 +239,7 @@ function isSavedBattleUnitState(value: unknown, options: BattleSaveValidationOpt
   }
 
   if (
-    !isPositiveInteger(value.level) ||
-    !isNonNegativeFiniteNumber(value.exp) ||
+    !isValidCharacterProgress(value.level, value.exp) ||
     !isNonNegativeFiniteNumber(value.hp) ||
     !isPositiveInteger(value.maxHp) ||
     Number(value.hp) > Number(value.maxHp) ||
@@ -282,11 +281,28 @@ function isEquipmentStateForSlot(value: unknown, slot: EquipmentSlot, options: B
     itemId.length > 0 &&
     (!options.validEquipmentItemIds || options.validEquipmentItemIds.has(itemId)) &&
     (!options.validEquipmentSlotItems?.[slot] || options.validEquipmentSlotItems[slot].has(itemId)) &&
-    isPositiveInteger(level) &&
-    isNonNegativeFiniteNumber(exp)
+    isValidEquipmentProgress(level, exp)
   );
 }
 
+function isValidCharacterProgress(level: unknown, exp: unknown) {
+  return (
+    isPositiveInteger(level) &&
+    Number.isInteger(exp) &&
+    Number(exp) >= 0 &&
+    (Number(level) >= 99 ? Number(exp) <= 100 : Number(exp) < 100)
+  );
+}
+
+function isValidEquipmentProgress(level: unknown, exp: unknown) {
+  if (!Number.isInteger(level) || Number(level) < 1 || Number(level) > 9 || !Number.isInteger(exp) || Number(exp) < 0) {
+    return false;
+  }
+
+  const next = equipmentExpToNext(Number(level));
+  return Number(level) >= 9 ? Number(exp) <= next : Number(exp) < next;
+}
+
 function isBondArray(value: unknown, options: BattleSaveValidationOptions) {
   return (
     Array.isArray(value) &&