From def6cb01559e2d7f77623226afe0ee3e99a71bdc Mon Sep 17 00:00:00 2001
From: Sketch <75850871+SketchMaster2001@users.noreply.github.com>
Date: Sun, 24 Sep 2023 15:29:07 -0400
Subject: [PATCH] IOS/KD: Fix crash with KD Scheduler

---
 Source/Core/Core/IOS/Network/KD/NWC24DL.cpp    | 12 ++++++++----
 Source/Core/Core/IOS/Network/KD/NWC24DL.h      |  2 +-
 .../Core/Core/IOS/Network/KD/NetKDRequest.cpp  | 18 ++++++++++++++++--
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/Source/Core/Core/IOS/Network/KD/NWC24DL.cpp b/Source/Core/Core/IOS/Network/KD/NWC24DL.cpp
index 34c5e4d1d1..58776828e6 100644
--- a/Source/Core/Core/IOS/Network/KD/NWC24DL.cpp
+++ b/Source/Core/Core/IOS/Network/KD/NWC24DL.cpp
@@ -100,9 +100,9 @@ std::string NWC24Dl::GetVFFPath(u16 entry_index) const
   return fmt::format("/title/{0:08x}/{1:08x}/data/wc24dl.vff", lower_title_id, high_title_id);
 }
 
-WC24PubkMod NWC24Dl::GetWC24PubkMod(u16 entry_index) const
+std::optional<WC24PubkMod> NWC24Dl::GetWC24PubkMod(u16 entry_index) const
 {
-  WC24PubkMod pubkMod;
+  WC24PubkMod pubk_mod;
   const u32 lower_title_id = Common::swap32(m_data.entries[entry_index].low_title_id);
   const u32 high_title_id = Common::swap32(m_data.entries[entry_index].high_title_id);
 
@@ -110,9 +110,13 @@ WC24PubkMod NWC24Dl::GetWC24PubkMod(u16 entry_index) const
       fmt::format("/title/{0:08x}/{1:08x}/data/wc24pubk.mod", lower_title_id, high_title_id);
 
   const auto file = m_fs->OpenFile(PID_KD, PID_KD, path, IOS::HLE::FS::Mode::Read);
-  file->Read(&pubkMod, 1);
+  if (!file)
+    return std::nullopt;
 
-  return pubkMod;
+  if (!file->Read(&pubk_mod, 1))
+    return std::nullopt;
+
+  return pubk_mod;
 }
 
 bool NWC24Dl::IsEncrypted(u16 entry_index) const
diff --git a/Source/Core/Core/IOS/Network/KD/NWC24DL.h b/Source/Core/Core/IOS/Network/KD/NWC24DL.h
index d6cbb8e9c8..6f5a05adae 100644
--- a/Source/Core/Core/IOS/Network/KD/NWC24DL.h
+++ b/Source/Core/Core/IOS/Network/KD/NWC24DL.h
@@ -37,7 +37,7 @@ public:
   std::string GetVFFContentName(u16 entry_index, std::optional<u8> subtask_id) const;
   std::string GetDownloadURL(u16 entry_index, std::optional<u8> subtask_id) const;
   std::string GetVFFPath(u16 entry_index) const;
-  WC24PubkMod GetWC24PubkMod(u16 entry_index) const;
+  std::optional<WC24PubkMod> GetWC24PubkMod(u16 entry_index) const;
 
   u64 GetNextDownloadTime(u16 record_index) const;
   u64 GetDownloadMargin(u16 entry_index) const;
diff --git a/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp b/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp
index 833bc5707f..7e8ab1d53b 100644
--- a/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp
+++ b/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp
@@ -522,6 +522,14 @@ NWC24::ErrorCode NetKDRequestDevice::KDDownload(const u16 entry_index,
   const std::string content_name = m_dl_list.GetVFFContentName(entry_index, subtask_id);
   std::string url = m_dl_list.GetDownloadURL(entry_index, subtask_id);
 
+  if (content_name.empty())
+  {
+    // If a content has an empty name it is meant to be saved to the mailbox. We do not support
+    // saving mail to the mailbox yet and as a result must skip these entries.
+    success = true;
+    return NWC24::WC24_OK;
+  }
+
   // Reroute to custom server if enabled.
   const std::vector<std::string> parts = SplitString(url, '/');
   if (parts.size() < 3)
@@ -588,11 +596,17 @@ NWC24::ErrorCode NetKDRequestDevice::KDDownload(const u16 entry_index,
 
     if (m_dl_list.IsEncrypted(entry_index))
     {
-      NWC24::WC24PubkMod pubk_mod = m_dl_list.GetWC24PubkMod(entry_index);
+      std::optional<NWC24::WC24PubkMod> pubk_mod = m_dl_list.GetWC24PubkMod(entry_index);
+      if (!pubk_mod)
+      {
+        ERROR_LOG_FMT(IOS_WC24, "Failed to get wc24pubk.mod for the current task.");
+        LogError(ErrorType::KD_Download, NWC24::WC24_ERR_FILE_OPEN);
+        return NWC24::WC24_ERR_FILE_OPEN;
+      }
 
       file_data = std::vector<u8>(response->size() - 320);
 
-      Common::AES::CryptOFB(pubk_mod.aes_key, wc24_file.iv, wc24_file.iv, temp_buffer.data(),
+      Common::AES::CryptOFB(pubk_mod->aes_key, wc24_file.iv, wc24_file.iv, temp_buffer.data(),
                             file_data.data(), temp_buffer.size());
     }
     else