Re: [PATCH 1/6] MdePkg/BaseLib: Refine (Ascii)StrnLenS functions logic

["Wu, Hao A" <hao.a.wu@intel.com>]

Mike,

I have noticed that the patch has the following issue:

According to the comments in functions [Ascii]StrnLens, at most the first
MaxSize characters of String shall be accessed by those two APIs.

But my patch will access (MaxSize + 1) characters of String if there is no
no null character in the first MaxSize characters in String.

Sorry for the issue, I will send out a V2 of the series with this patch
updated.


Best Regards,
Hao Wu


> -----Original Message-----
> From: Kinney, Michael D
> Sent: Friday, December 16, 2016 7:55 AM
> To: Wu, Hao A; edk2-devel@lists.01.org; Kinney, Michael D
> Cc: Wu, Hao A; Yao, Jiewen; Gao, Liming
> Subject: RE: [edk2] [PATCH 1/6] MdePkg/BaseLib: Refine (Ascii)StrnLenS
> functions logic
> 
> Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
> 
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Hao
> Wu
> > Sent: Wednesday, December 14, 2016 3:27 AM
> > To: edk2-devel@lists.01.org
> > Cc: Wu, Hao A <hao.a.wu@intel.com>; Kinney, Michael D
> <michael.d.kinney@intel.com>;
> > Yao, Jiewen <jiewen.yao@intel.com>; Gao, Liming <liming.gao@intel.com>
> > Subject: [edk2] [PATCH 1/6] MdePkg/BaseLib: Refine (Ascii)StrnLenS functions
> logic
> >
> > This commit refines the logic for AsciiStrnLenS and StrnLenS. It makes the
> > logic more straightforward to prevent possible mis-reports by static code
> > checkers.
> >
> > Cc: Jiewen Yao <jiewen.yao@intel.com>
> > Cc: Liming Gao <liming.gao@intel.com>
> > Cc: Michael D Kinney <michael.d.kinney@intel.com>
> > Contributed-under: TianoCore Contribution Agreement 1.0
> > Signed-off-by: Hao Wu <hao.a.wu@intel.com>
> > ---
> >  MdePkg/Library/BaseLib/SafeString.c | 16 ++++++++++++----
> >  1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/MdePkg/Library/BaseLib/SafeString.c
> > b/MdePkg/Library/BaseLib/SafeString.c
> > index ede2f4c..3247d28 100644
> > --- a/MdePkg/Library/BaseLib/SafeString.c
> > +++ b/MdePkg/Library/BaseLib/SafeString.c
> > @@ -143,8 +143,12 @@ StrnLenS (
> >    // String then StrnLenS returns MaxSize. At most the first MaxSize
> characters of
> > String shall
> >    // be accessed by StrnLenS.
> >    //
> > -  for (Length = 0; (Length < MaxSize) && (*String != 0); String++, Length++) {
> > -    ;
> > +  Length = 0;
> > +  while (String[Length] != 0) {
> > +    if (Length >= MaxSize) {
> > +      break;
> > +    }
> > +    Length++;
> >    }
> >    return Length;
> >  }
> > @@ -571,8 +575,12 @@ AsciiStrnLenS (
> >    // String then AsciiStrnLenS returns MaxSize. At most the first MaxSize
> characters
> > of String shall
> >    // be accessed by AsciiStrnLenS.
> >    //
> > -  for (Length = 0; (Length < MaxSize) && (*String != 0); String++, Length++) {
> > -    ;
> > +  Length = 0;
> > +  while (String[Length] != 0) {
> > +    if (Length >= MaxSize) {
> > +      break;
> > +    }
> > +    Length++;
> >    }
> >    return Length;
> >  }
> > --
> > 1.9.5.msysgit.0
> >
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