From b46de50913dea36d24637394c41d34095bfdaee2 Mon Sep 17 00:00:00 2001
From: Ruiyu Ni <ruiyu.ni@intel.com>
Date: Wed, 7 Nov 2018 17:34:20 +0800
Subject: [PATCH] ShellPkg/ShellLib: Fix potential NULL deference issue
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1310

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jim Dailey <jim_dailey@dell.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
---
 ShellPkg/Library/UefiShellLib/UefiShellLib.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/ShellPkg/Library/UefiShellLib/UefiShellLib.c b/ShellPkg/Library/UefiShellLib/UefiShellLib.c
index 580a1ee612..b17266d623 100644
--- a/ShellPkg/Library/UefiShellLib/UefiShellLib.c
+++ b/ShellPkg/Library/UefiShellLib/UefiShellLib.c
@@ -72,6 +72,7 @@ FullyQualifyPath(
 {
   CONST CHAR16         *WorkingPath;
   CONST CHAR16         *InputPath;
+  CHAR16               *CharPtr;
   CHAR16               *InputFileSystem;
   UINTN                FileSystemCharCount;
   CHAR16               *FullyQualifiedPath;
@@ -131,7 +132,10 @@ FullyQualifyPath(
         // truncate the new path after the file system part.
         //
         StrCpyS(FullyQualifiedPath, Size/sizeof(CHAR16), WorkingPath);
-        *(StrStr(FullyQualifiedPath, L":") + 1) = CHAR_NULL;
+        CharPtr = StrStr(FullyQualifiedPath, L":");
+        if (CharPtr != NULL) {
+          *(CharPtr + 1) = CHAR_NULL;
+        }
       } else {
         //
         // Relative path: start with the working directory and append "\".