Buffer overwrite in libstdc++-v3 test 21_strings/c_strings.c

Hans-Peter Nilsson hans-peter.nilsson@axis.com
Mon Sep 24 07:37:00 GMT 2001


> Date: Mon, 24 Sep 2001 22:24:35 +0800 (SGT)
> From: Greg Hosler <hosler@lugs.org.sg>

> On 24-Sep-2001 Hans-Peter Nilsson wrote:
> > Is this some C++ gotcha or is there an obvious buffer-overwrite
> > here?  The CRIS gcc port and the simulator dump says the buffer
> > is overwritten, but there's no absolute truth in that.
> > 
> >  ...
> >   const char* ccarray1 = "san francisco roof garden inspectors";
> >   const char* ccarray2 = "san francisco sunny-day park inspectors";
> >   char carray[30];
> >   std::strcpy(carray, ccarray1);
> >  ...
> > 
> > Will trade patch for clue.
> 
> how do you fit 37 characters (i.e. strlen(ccarray1) + 1 for the null)
> into 30 char buffer (size of carray), without overflowing it ?

That's the question I'm asking.  But presumably some corner in
that pile of papers called a C++ standards document could
interpret to say that strcpy should "DWIM" here.  Anyway, since
now two people see the same thing I do, enough said.

brgds, H-P



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