[syslinux] [PATCH] chrreplace: Don't skip the first character

[Erwan Velu]

Got it but that might happen. Better avoiding that. Thanks for the fix
Le 28 sept. 2015 4:10 PM, "Josh Triplett" <josh at joshtriplett.org> a écrit :

> On Mon, Sep 28, 2015 at 10:29:16AM +0200, Erwan Velu wrote:
> > Just looking at the code and the description of it, for me the current
> code
> > looks wrong and the proposed patch correct for the following reason:
> >
> > The while loop is made for insuring that *source is valid but just after
> > shift the pointer by one.
> > This new position isn't tested and so we are addressing an unknown area.
> > That could corrupt some memory.
>
> Fortunately, as long as the string terminates with a '\0' (and someone
> doesn't pass '\0' as "old"), this can't actually overrun.
>
> > But also as reported, that prevent from changing the first char.
> >
> > I've been contributing that code and sounds like only the code I produced
> > is using it (hdt & the pci scan).
> > So I'd vote for including that patch. If any regression occur, I'd look
> at
> > it.
> >
> > Thanks for reporting, +1 for the merge.
>
> Thanks.
>
> - Josh Triplett
>
> > 2015-09-22 12:45 GMT+02:00 Gene Cumm <gene.cumm at gmail.com>:
> >
> > > Erwan, could you shed some light on this?  Was the behavior
> > > intentional?  If not, I think it might prove more useful down the road
> > > to commit this patch.  Original code in commit ID 85d9a1a
> > >
> > > --
> > > -Gene
> > >
> > > On Sat, May 16, 2015 at 3:30 AM, Josh Triplett via Syslinux
> > > <syslinux at zytor.com> wrote:
> > > > Check if the first character matches the character to replace, rather
> > > > than skipping it and starting with the second.
> > > >
> > > > Signed-off-by: Josh Triplett <josh at joshtriplett.org>
> > > > ---
> > > >
> > > > I'm assuming, based on a look at the callers, that this is not
> > > > intentional, and that it just happened that none of the callers
> happened
> > > > to ever need to replace the first character.
> > > >
> > > >  com32/lib/chrreplace.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/com32/lib/chrreplace.c b/com32/lib/chrreplace.c
> > > > index 65786f9..cfbf5d4 100644
> > > > --- a/com32/lib/chrreplace.c
> > > > +++ b/com32/lib/chrreplace.c
> > > > @@ -4,8 +4,8 @@
> > > >  void chrreplace(char *source, char old, char new)
> > > >  {
> > > >      while (*source) {
> > > > -       source++;
> > > >         if (source[0] == old) source[0]=new;
> > > > +       source++;
> > > >      }
> > > >  }
> > > >
> > >
>