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From: Noah Goldstein <goldstein.w.n@gmail.com>
Date: Wed, 10 Aug 2022 11:29:49 +0800
Message-ID: <CAFUsyf+-C3F6LS9Ui4kDajC227MFGQMK0iLgX7w8XW7yo=SgXA@mail.gmail.com>
Subject: Re: [PATCH v1] elf: Replace `strcpy` call with `memcpy` [BZ #29454]
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>,
 "Carlos O'Donell" <carlos@systemhalted.org>
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On Mon, Aug 8, 2022 at 10:24 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Sun, Aug 7, 2022 at 8:26 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > GCC normally does this optimization for us in
> > strlen_pass::handle_builtin_strcpy but only for optimized
> > build. To avoid needing to include strcpy.S in the rtld build to
> > support the debug build, just do the optimization by hand.
> > ---
> >  elf/dl-cache.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/elf/dl-cache.c b/elf/dl-cache.c
> > index 8bbf110d02..b97c17b3a9 100644
> > --- a/elf/dl-cache.c
> > +++ b/elf/dl-cache.c
> > @@ -509,8 +509,9 @@ _dl_load_cache_lookup (const char *name)
> >       we are accessing. Therefore we must make the copy of the
> >       mapping data without using malloc.  */
> >    char *temp;
> > -  temp = alloca (strlen (best) + 1);
> > -  strcpy (temp, best);
> > +  size_t best_len = strlen (best) + 1;
> > +  temp = alloca (best_len);
> > +  memcpy (temp, best, best_len);
> >    return __strdup (temp);
> >  }
> >
> > --
> > 2.34.1
> >
>
> LGTM.
>
> Thanks.
>
> --
> H.J.

Any objections to backporting this to 2.36?