[PATCH] ShellPkg/ShellLib: Fix potential NULL deference issue

[Ruiyu Ni <ruiyu.ni@intel.com>]

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jim Dailey <jim_dailey@dell.com>
Cc: Hao A Wu <hao.a.wu@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 "\".
-- 
2.16.1.windows.1