[MOUNTMGR] Few fixes and improvements (#7896)

- `MountMgrVolumeMountPointChanged()`: Set status code in all failure
  paths and correct the check for remote or removable media.
- `DeleteRemoteDatabaseEntry()`: Do not allow the database with size of zero.
- `QueryVolumeName()`: Use reparse point file reference when no file name is supplied.

drivers/storage/mountmgr/database.c

@@ -255,8 +255,8 @@ DeleteRemoteDatabaseEntry(IN HANDLE Database,
         return STATUS_INVALID_PARAMETER;
     }
 
-    /* Validate parameters: ensure we won't get negative size */
-    if (Entry->EntrySize + StartingOffset > DatabaseSize)
+    /* Validate parameters: ensure we won't get zero or negative size */
+    if (Entry->EntrySize + StartingOffset >= DatabaseSize)
     {
         /* If we get invalid parameters, truncate the whole database
          * starting the wrong entry. We can't rely on the rest
@@ -1303,12 +1303,14 @@ QueryVolumeName(IN HANDLE RootDirectory,
     PFILE_NAME_INFORMATION FileNameInfo;
     PREPARSE_DATA_BUFFER ReparseDataBuffer;
 
-    UNREFERENCED_PARAMETER(ReparsePointInformation);
-
     if (!FileName)
     {
+        UNICODE_STRING Reference;
+
+        Reference.Length = Reference.MaximumLength = sizeof(ReparsePointInformation->FileReference);
+        Reference.Buffer = (PWSTR)&(ReparsePointInformation->FileReference);
         InitializeObjectAttributes(&ObjectAttributes,
-                                   NULL,
+                                   &Reference,
                                    OBJ_KERNEL_HANDLE,
                                    RootDirectory,
                                    NULL);

drivers/storage/mountmgr/device.c

@@ -2062,13 +2062,17 @@ MountMgrVolumeMountPointChanged(IN PDEVICE_EXTENSION DeviceExtension,
         goto Cleanup;
     }
 
+    /* Mount points can be stored only on storage disks */
     if (FsDeviceInfo.DeviceType != FILE_DEVICE_DISK && FsDeviceInfo.DeviceType != FILE_DEVICE_VIRTUAL_DISK)
     {
+        Status = STATUS_INVALID_PARAMETER;
         goto Cleanup;
     }
 
-    if (FsDeviceInfo.Characteristics != (FILE_REMOTE_DEVICE | FILE_REMOVABLE_MEDIA))
+    /* And they can be on local fixed disks only */
+    if (FsDeviceInfo.Characteristics & (FILE_REMOTE_DEVICE | FILE_REMOVABLE_MEDIA))
     {
+        Status = STATUS_INVALID_PARAMETER;
         goto Cleanup;
     }