Re: Compiler Memory Alignment Issue

["Yann E. MORIN" <yann dot morin dot 1998 at free dot fr>]

Johannes, Richard, Bob, Martin, All,

On Friday 03 February 2012 15:13:59 Johannes Stezenbach wrote:
> On Fri, Feb 03, 2012 at 02:21:23PM +0100, Yann E. MORIN wrote:
> > On Friday 03 February 2012 11:16:27 Bob Dunlop wrote:
> > > On Thu, Feb 02 at 01:15, Richard Koch wrote:
> > > > I'm seeing an alignment issue when I'm incrementing a pointer.
> > 
> > I Just tried your .config and your sample C code, and it seems to work here
> > (with the buffer overflow fixed):
> 
> As Martin Guy pointed out the issue may be caused
> by wrong alignment.  In fact the behaviour of the code
> is undefined according to C99 if buffer is not suitably aligned:
> https://www.securecoding.cert.org/confluence/display/seccode/EXP36-C.+Do+not+convert+pointers+into+more+strictly+aligned+pointer+types

Indeed, but with the same .config (ie the same compiler settings), and the
same code, I get a correct result, where Richard does not.

Regards,
Yann E. MORIN.

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