ShellPkg/ShellLib: Fix potential NULL deference issue

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>

1 files changed, 5 insertions, 1 deletions

diff --git a/ShellPkg/Library/UefiShellLib/UefiShellLib.c b/ShellPkg/Library/UefiShellLib/UefiShellLib.c
index 580a1ee..b17266d 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 "\".