Check file system validity before reading opening.bnr

This happened to work without any problems because the only way for a
file system to be invalid was to not have the right GC/Wii magic word
in the unencrypted area, and a volume could not be created without
having the right GC/Wii magic word there. Now that file systems read
the magic word from a partition instead, a fix is needed.

2 files changed, 6 insertions, 1 deletions

diff --git a/Source/Core/DiscIO/VolumeGC.cpp b/Source/Core/DiscIO/VolumeGC.cpp
index 6f7568a3a1..d6abd08263 100644
--- a/Source/Core/DiscIO/VolumeGC.cpp
+++ b/Source/Core/DiscIO/VolumeGC.cpp
@@ -193,8 +193,10 @@ void CVolumeGC::LoadBannerFile() const
 
   GCBanner banner_file;
   std::unique_ptr<IFileSystem> file_system(CreateFileSystem(this, PARTITION_NONE));
-  size_t file_size = static_cast<size_t>(file_system->GetFileSize("opening.bnr"));
+  if (!file_system)
+    return;
 
+  size_t file_size = static_cast<size_t>(file_system->GetFileSize("opening.bnr"));
   constexpr int BNR1_MAGIC = 0x31524e42;
   constexpr int BNR2_MAGIC = 0x32524e42;
   if (file_size != BNR1_SIZE && file_size != BNR2_SIZE)
diff --git a/Source/Core/DiscIO/VolumeWiiCrypted.cpp b/Source/Core/DiscIO/VolumeWiiCrypted.cpp
index 310d447c43..05d34aa126 100644
--- a/Source/Core/DiscIO/VolumeWiiCrypted.cpp
+++ b/Source/Core/DiscIO/VolumeWiiCrypted.cpp
@@ -299,6 +299,9 @@ std::string CVolumeWiiCrypted::GetInternalName(const Partition& partition) const
 std::map<Language, std::string> CVolumeWiiCrypted::GetLongNames() const
 {
   std::unique_ptr<IFileSystem> file_system(CreateFileSystem(this, GetGamePartition()));
+  if (!file_system)
+    return {{}};
+
   std::vector<u8> opening_bnr(NAMES_TOTAL_BYTES);
   size_t size = file_system->ReadFile("opening.bnr", opening_bnr.data(), opening_bnr.size(), 0x5C);
   opening_bnr.resize(size);