From 014b9850f2a33ae402b87c46268f4d98395d5d59 Mon Sep 17 00:00:00 2001
From: "wenyi,xie via groups.io" <xiewenyi2=huawei.com@groups.io>
Date: Tue, 12 Jan 2021 15:06:38 +0800
Subject: MdeModulePkg/FileExplorerLib: Add return value check

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>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Dandan Bi <dandan.bi@intel.com>
---
 MdeModulePkg/Library/FileExplorerLib/FileExplorer.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

(limited to 'MdeModulePkg')

diff --git a/MdeModulePkg/Library/FileExplorerLib/FileExplorer.c b/MdeModulePkg/Library/FileExplorerLib/FileExplorer.c
index 13a214b06a..03630a29bc 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);
   }
-- 
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