From 3f780fdd69cbb59fb0ce9519faa467df9e8600f2 Mon Sep 17 00:00:00 2001
From: Gericom <fnouwt2@gmail.com>
Date: Sun, 29 Mar 2026 11:47:08 +0200
Subject: [PATCH] Improve error handling for parsing banners. Fixes #18

---
 .../FileType/Nds/NdsInternalFileInfo.cpp      | 68 +++++++++++--------
 .../FileType/Nds/NdsInternalFileInfo.h        | 11 +--
 2 files changed, 40 insertions(+), 39 deletions(-)

diff --git a/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.cpp b/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.cpp
index c1a14c3..54c01a4 100644
--- a/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.cpp
+++ b/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.cpp
@@ -2,52 +2,60 @@
 #include <string.h>
 #include <nds/arm9/cache.h>
 #include "fat/File.h"
-#include "romBrowser/ICoverRepository.h"
 #include "NdsInternalFileInfo.h"
 
 NdsInternalFileInfo::NdsInternalFileInfo(const FastFileRef& fastFileRef)
 {
     const auto file = std::make_unique<File>();
-    _hasBanner = false;
     memset(_gameCode, 0, sizeof(_gameCode));
 
     file->Open(fastFileRef, FA_READ);
 
-    if (file->Seek(0xC) != FR_OK)
-        return;
-
-    u32 bytesRead;
-    if (file->Read(_gameCode, 4, bytesRead) != FR_OK)
-        return;
-
-    if (file->Seek(0x68) != FR_OK)
-        return;
-
     u32 bannerOffset;
-    if (file->Read(&bannerOffset, 4, bytesRead) != FR_OK)
-        return;
-
-    if (bannerOffset == 0)
-        return;
-
-    if (file->Seek(bannerOffset) != FR_OK)
-        return;
-
-    if (file->Read(&_banner, 0xA00, bytesRead) != FR_OK)
-        return;
-
-    if (_banner.header.version >= NDS_BANNER_VERSION_103)
+    if (file->Seek(0xC) != FR_OK ||
+        !file->ReadExact(_gameCode, 4) ||
+        file->Seek(0x68) != FR_OK ||
+        !file->ReadExact(&bannerOffset, 4) ||
+        bannerOffset == 0 ||
+        bannerOffset >= file->GetSize() ||
+        file->Seek(bannerOffset) != FR_OK ||
+        !file->ReadExact(&_banner, 0x840))
     {
-        if (file->Read(((u8*)&_banner) + 0xA00, 0x19C0, bytesRead) != FR_OK)
-            return;
+        return;
     }
+
+    if (_banner.header.version >= NDS_BANNER_VERSION_2 &&
+        !file->ReadExact(((u8*)&_banner) + 0x840, 0x100))
+    {
+        return;
+    }
+
+    if (_banner.header.version >= NDS_BANNER_VERSION_3 &&
+        !file->ReadExact(((u8*)&_banner) + 0x940, 0x100))
+    {
+        return;
+    }
+
+    if (_banner.header.version >= NDS_BANNER_VERSION_103 &&
+        !file->ReadExact(((u8*)&_banner) + 0xA40, 0x1980))
+    {
+        return;
+    }
+
     _hasBanner = true;
     DC_FlushRange(&_banner, sizeof(_banner));
 }
 
 const char16_t* NdsInternalFileInfo::GetGameTitle() const
 {
-    if (!_hasBanner)
-        return nullptr;
-    return _banner.title[NDS_BANNER_TITLE_LANGUAGE_ENGLISH];
+    return _hasBanner
+        ? _banner.title[NDS_BANNER_TITLE_LANGUAGE_ENGLISH]
+        : nullptr;
+}
+
+std::unique_ptr<FileIcon> NdsInternalFileInfo::CreateGameIcon() const
+{
+    return _hasBanner
+        ? std::make_unique<NdsFileIcon>(&_banner)
+        : nullptr;
 }
diff --git a/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.h b/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.h
index 0c7571e..736870a 100644
--- a/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.h
+++ b/arm9/source/romBrowser/FileType/Nds/NdsInternalFileInfo.h
@@ -12,18 +12,11 @@ public:
 
     constexpr const char* GetGameCode() const override { return _gameCode; }
     const char16_t* GetGameTitle() const override;
-
-    std::unique_ptr<FileIcon> CreateGameIcon() const override
-    {
-        if (!_hasBanner)
-            return nullptr;
-        return std::make_unique<NdsFileIcon>(&_banner);
-    }
-
+    std::unique_ptr<FileIcon> CreateGameIcon() const override;
     const nds_banner_t& GetBanner() const { return _banner; }
 
 private:
     nds_banner_t _banner alignas(32);
-    bool _hasBanner;
+    bool _hasBanner = false;
     char _gameCode[5];
 };
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