[PATCH] MdePkg/UefiFileHandleLib: Fix potential NULL dereference.

["Marvin Häuser" <Marvin.Haeuser@outlook.com>]

Move the NULL-check in FileHandleGetInfo() to directly after the
allocation to prevent potential NULL dereferences.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marvin Haeuser <Marvin.Haeuser@outlook.com>
---
 MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c | 30 +++++++++++---------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
index 57aad77bc135..bcf3a328b82d 100644
--- a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
+++ b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
@@ -1,7 +1,7 @@
 /** @file
   Provides interface to EFI_FILE_HANDLE functionality.
 
-  Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved. <BR>
+  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved. <BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -74,19 +74,21 @@ FileHandleGetInfo (
     // error is expected.  getting size to allocate
     //
     FileInfo = AllocateZeroPool(FileInfoSize);
-    //
-    // now get the information
-    //
-    Status = FileHandle->GetInfo(FileHandle,
-                                 &gEfiFileInfoGuid,
-                                 &FileInfoSize,
-                                 FileInfo);
-    //
-    // if we got an error free the memory and return NULL
-    //
-    if (EFI_ERROR(Status) && (FileInfo != NULL)) {
-      FreePool(FileInfo);
-      FileInfo = NULL;
+    if (FileInfo != NULL) {
+      //
+      // now get the information
+      //
+      Status = FileHandle->GetInfo(FileHandle,
+                                   &gEfiFileInfoGuid,
+                                   &FileInfoSize,
+                                   FileInfo);
+      //
+      // if we got an error free the memory and return NULL
+      //
+      if (EFI_ERROR(Status)) {
+        FreePool(FileInfo);
+        FileInfo = NULL;
+      }
     }
   }
   return (FileInfo);
-- 
2.17.0.windows.1