[PATCH EDK2 v1 1/1] MdeModulePkg/FileExplorerLib: Add return value check

["wenyi,xie" <xiewenyi2@huawei.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3113
According to FAT specification, the length of file path
should not larger than 260. When the length exceed 260,
function FatLocateOFile will return EFI_INVALID_PARAMETER
and the parameter FileHandle will be NULL. Then on the
top-level function，an exception happens when the NULL
pointer is passed and be used.
So adding return value check after calling
LibGetFileHandleFromMenu, if return value is not success,
stop calling LibFindFiles.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Signed-off-by: Wenyi Xie <xiewenyi2@huawei.com>
---
 MdeModulePkg/Library/FileExplorerLib/FileExplorer.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/MdeModulePkg/Library/FileExplorerLib/FileExplorer.c b/MdeModulePkg/Library/FileExplorerLib/FileExplorer.c
index 13a214b06af9..03630a29bc3b 100644
--- a/MdeModulePkg/Library/FileExplorerLib/FileExplorer.c
+++ b/MdeModulePkg/Library/FileExplorerLib/FileExplorer.c
@@ -1408,12 +1408,14 @@ LibUpdateFileExplorer (
   if (NewFileContext->IsDir) {
     RemoveEntryList (&NewMenuEntry->Link);
     LibFreeMenu (gFileExplorerPrivate.FsOptionMenu);
-    LibGetFileHandleFromMenu (NewMenuEntry, &FileHandle);
-    Status = LibFindFiles (FileHandle, NewFileContext->FileName, NewFileContext->DeviceHandle);
+    Status = LibGetFileHandleFromMenu (NewMenuEntry, &FileHandle);
     if (!EFI_ERROR (Status)) {
-      LibUpdateFileExplorePage ();
-    } else {
-      LibFreeMenu (gFileExplorerPrivate.FsOptionMenu);
+      Status = LibFindFiles (FileHandle, NewFileContext->FileName, NewFileContext->DeviceHandle);
+      if (!EFI_ERROR (Status)) {
+        LibUpdateFileExplorePage ();
+      } else {
+        LibFreeMenu (gFileExplorerPrivate.FsOptionMenu);
+      }
     }
     LibDestroyMenuEntry (NewMenuEntry);
   }
-- 
2.20.1.windows.1