Fix fuzzing-discovered issues in filesystem drivers

Ext4Pkg/Ext4Dxe/Ext4Dxe.h

@@ -715,6 +715,27 @@ Ext4WriteFile (
   IN VOID               *Buffer
   );
 
+/**
+  Flushes all modified data associated with a file to a device
+
+  @param[in]      This        A pointer to the EFI_FILE_PROTOCOL instance that is the file
+                              handle to flush data.
+
+  @retval EFI_SUCCESS          The data was flushed.
+  @retval EFI_NO_MEDIA         The device has no medium.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The file or medium is write-protected.
+  @retval EFI_ACCESS_DENIED    The file was opened read only.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+Ext4Flush (
+  IN EFI_FILE_PROTOCOL  *This
+  );
+
 /**
   Returns a file's current position.
 

Ext4Pkg/Ext4Dxe/File.c

@@ -555,6 +555,37 @@ Ext4WriteFile (
   return EFI_WRITE_PROTECTED;
 }
 
+/**
+  Flushes all modified data associated with a file to a device
+
+  @param[in]      This        A pointer to the EFI_FILE_PROTOCOL instance that is the file
+                              handle to flush data.
+
+  @retval EFI_SUCCESS          The data was flushed.
+  @retval EFI_NO_MEDIA         The device has no medium.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The file or medium is write-protected.
+  @retval EFI_ACCESS_DENIED    The file was opened read only.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+Ext4Flush (
+  IN EFI_FILE_PROTOCOL  *This
+  )
+{
+  EXT4_FILE  *File;
+
+  File = EXT4_FILE_FROM_THIS (This);
+  if (!(File->OpenMode & EFI_FILE_MODE_WRITE)) {
+    return EFI_ACCESS_DENIED;
+  }
+
+  return EFI_WRITE_PROTECTED;
+}
+
 /**
   Returns a file's current position.
 

Ext4Pkg/Ext4Dxe/Partition.c

@@ -89,6 +89,7 @@ Ext4SetupFile (
   File->Protocol.GetPosition = Ext4GetPosition;
   File->Protocol.GetInfo     = Ext4GetInfo;
   File->Protocol.SetInfo     = Ext4SetInfo;
+  File->Protocol.Flush       = Ext4Flush;
 
   File->Partition = Partition;
 }

Ext4Pkg/Ext4Dxe/Superblock.c

@@ -199,6 +199,21 @@ Ext4OpenSuperblock (
     // GOOD_OLD_REV
     Partition->FeaturesCompat = Partition->FeaturesIncompat = Partition->FeaturesRoCompat = 0;
     Partition->InodeSize      = EXT4_GOOD_OLD_INODE_SIZE;
+
+    //
+    // We must ensure that Sb->s_feature_incompat is also zero; otherwise,
+    // we must not mount this file system.
+    //
+    if (Sb->s_feature_incompat != 0) {
+      return EFI_VOLUME_CORRUPTED;
+    }
+
+    //
+    // Check that Sb->s_inode_size is valid, otherwise the partition is likely corrupted.
+    //
+    if (Sb->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
+      return EFI_VOLUME_CORRUPTED;
+    }
   }
 
   // Now, check for the feature set of the filesystem

FatPkg/EnhancedFatDxe/DirectoryManage.c

@@ -478,7 +478,7 @@ FatGetDirEntInfo (
     Info       = Buffer;
     Info->Size = ResultSize;
     if ((Entry->Attributes & FAT_ATTRIBUTE_DIRECTORY) != 0) {
-      Cluster            = (Entry->FileClusterHigh << 16) | Entry->FileCluster;
+      Cluster            = ((((UINTN) Entry->FileClusterHigh) << 16) | ((UINTN) Entry->FileCluster));
       Info->PhysicalSize = FatPhysicalDirSize (Volume, Cluster);
       Info->FileSize     = Info->PhysicalSize;
     } else {
@@ -1190,7 +1190,7 @@ FatOpenDirEnt (
       //
       Volume             = Parent->Volume;
       OFile->FullPathLen = Parent->FullPathLen + 1 + StrLen (DirEnt->FileString);
-      OFile->FileCluster = ((DirEnt->Entry.FileClusterHigh) << 16) | (DirEnt->Entry.FileCluster);
+      OFile->FileCluster = (((UINTN) DirEnt->Entry.FileClusterHigh) << 16) | ((UINTN) DirEnt->Entry.FileCluster);
       InsertTailList (&Parent->ChildHead, &OFile->ChildLink);
     } else {
       //

FatPkg/EnhancedFatDxe/ReadWrite.c

@@ -318,6 +318,8 @@ FatIFileAccess (
     }
   }
 
+Done:
+
   if (Token != NULL) {
     if (!EFI_ERROR (Status)) {
       Status = FatQueueTask (IFile, Task);
@@ -326,7 +328,6 @@ FatIFileAccess (
     }
   }
 
-Done:
   //
   // On EFI_SUCCESS case, not calling FatCleanupVolume():
   // 1) The Cache flush operation is avoided to enhance