Re: [patch v2] BaseTools/VfrCompile: Avoid using uninitialized pointer

[Gary Lin <glin@suse.com>]

On Wed, May 09, 2018 at 01:02:11PM +0800, Dandan Bi wrote:
> 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.
> 
This patch fixes the build errors I had :)

Tested-by: Gary Lin <glin@suse.com>

> Cc: Eric Dong <eric.dong@intel.com>
> 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>
> ---
>  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 4b0a43606ea..84dd2c3ed3f 100644
> --- a/BaseTools/Source/C/VfrCompile/VfrSyntax.g
> +++ b/BaseTools/Source/C/VfrCompile/VfrSyntax.g
> @@ -4084,11 +4084,19 @@ 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()); >>
>    )*
>                                                         <<
> @@ -4988,10 +4996,11 @@ private:
>    CIfrOpHeader *      mCIfrOpHdr[MAX_IFR_EXPRESSION_DEPTH];
>    UINT32              mCIfrOpHdrLineNo[MAX_IFR_EXPRESSION_DEPTH];
>    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);
>  
>  
>    EFI_VARSTORE_INFO   mCurrQestVarInfo;
>    EFI_GUID            *mOverrideClassGuid;
> @@ -5077,20 +5086,28 @@ EfiVfrParser::_SAVE_OPHDR_COND (
>      mCIfrOpHdr[mCIfrOpHdrIndex]       = new CIfrOpHeader(OpHdr);
>      mCIfrOpHdrLineNo[mCIfrOpHdrIndex] = LineNo;
>    }
>  }
>  
> +VOID
> +EfiVfrParser::_INIT_OPHDR_COND (
> +  VOID
> +  )
> +{
> +  mCIfrOpHdr[mCIfrOpHdrIndex]       = NULL;
> +  mCIfrOpHdrLineNo[mCIfrOpHdrIndex] = 0;
> +}
> +
>  VOID
>  EfiVfrParser::_CLEAR_SAVED_OPHDR (
>    VOID
>    )
>  {
>    if (mCIfrOpHdr[mCIfrOpHdrIndex] != NULL) {
>      delete mCIfrOpHdr[mCIfrOpHdrIndex];
> -    mCIfrOpHdr[mCIfrOpHdrIndex]     = NULL;
> +    mCIfrOpHdr[mCIfrOpHdrIndex] = NULL;
>    }
> -  mCIfrOpHdrLineNo[mCIfrOpHdrIndex] = 0;
>  }
>  
>  BOOLEAN
>  EfiVfrParser::_SET_SAVED_OPHDR_SCOPE (
>    VOID
> -- 
> 2.14.3.windows.1
> 
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