From 13e3f8c03339ebc8cd25c454fca1abde098fe7ed Mon Sep 17 00:00:00 2001
From: "Bi, Dandan" <dandan.bi@intel.com>
Date: Wed, 9 May 2018 13:02:11 +0800
Subject: [PATCH] BaseTools/VfrCompile: Avoid using uninitialized pointer

V2:
Add function _INIT_OPHDR_COND () for variable initialization.
Make code logic more clean.

Previously _CLEAR_SAVED_OPHDR () is used for variable
initialization, and we updated it to clean memory.
But _CLEAR_SAVED_OPHDR () is still called for variable
initialization. This will cause uninitialized pointer
will be checked to free and cause unexpected issue.

This patch is to add new function for variable initialization
and keep _CLEAR_SAVED_OPHDR () to clean memory which is
aligned with its function name.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Gary Lin <glin@suse.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
---
 BaseTools/Source/C/VfrCompile/VfrSyntax.g | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/BaseTools/Source/C/VfrCompile/VfrSyntax.g b/BaseTools/Source/C/VfrCompile/VfrSyntax.g
index 4b0a43606e..84dd2c3ed3 100644
--- a/BaseTools/Source/C/VfrCompile/VfrSyntax.g
+++ b/BaseTools/Source/C/VfrCompile/VfrSyntax.g
@@ -4086,7 +4086,15 @@ vfrStatementInvalidSaveRestoreDefaults :
 // Root expression extension function called by other function.
 //
 vfrStatementExpression [UINT32 RootLevel, UINT32 ExpOpCount = 0] :
-  << if ($RootLevel == 0) {mCIfrOpHdrIndex ++; if (mCIfrOpHdrIndex >= MAX_IFR_EXPRESSION_DEPTH) _PCATCH (VFR_RETURN_INVALID_PARAMETER, 0, "The depth of expression exceeds the max supported level 8!"); _CLEAR_SAVED_OPHDR ();} >>
+                                                       <<
+                                                          if ($RootLevel == 0) {
+                                                            mCIfrOpHdrIndex ++;
+                                                            if (mCIfrOpHdrIndex >= MAX_IFR_EXPRESSION_DEPTH) {
+                                                              _PCATCH (VFR_RETURN_INVALID_PARAMETER, 0, "The depth of expression exceeds the max supported level 8!");
+                                                            }
+                                                            _INIT_OPHDR_COND ();
+                                                          }
+                                                       >>
   andTerm[$RootLevel, $ExpOpCount]
   (
     L:OR andTerm[$RootLevel, $ExpOpCount]              << $ExpOpCount++; CIfrOr OObj(L->getLine()); >>
@@ -4990,6 +4998,7 @@ private:
   UINT8               mCIfrOpHdrIndex;
   VOID                _SAVE_OPHDR_COND (IN CIfrOpHeader &, IN BOOLEAN, UINT32 LineNo = 0);
   VOID                _CLEAR_SAVED_OPHDR (VOID);
+  VOID                _INIT_OPHDR_COND (VOID);
   BOOLEAN             _SET_SAVED_OPHDR_SCOPE (VOID);
 
 
@@ -5079,6 +5088,15 @@ EfiVfrParser::_SAVE_OPHDR_COND (
   }
 }
 
+VOID
+EfiVfrParser::_INIT_OPHDR_COND (
+  VOID
+  )
+{
+  mCIfrOpHdr[mCIfrOpHdrIndex]       = NULL;
+  mCIfrOpHdrLineNo[mCIfrOpHdrIndex] = 0;
+}
+
 VOID
 EfiVfrParser::_CLEAR_SAVED_OPHDR (
   VOID
@@ -5086,9 +5104,8 @@ EfiVfrParser::_CLEAR_SAVED_OPHDR (
 {
   if (mCIfrOpHdr[mCIfrOpHdrIndex] != NULL) {
     delete mCIfrOpHdr[mCIfrOpHdrIndex];
-    mCIfrOpHdr[mCIfrOpHdrIndex]     = NULL;
+    mCIfrOpHdr[mCIfrOpHdrIndex] = NULL;
   }
-  mCIfrOpHdrLineNo[mCIfrOpHdrIndex] = 0;
 }
 
 BOOLEAN