crash in newlocale()

[Takashi Yano]

On Thu, 11 Aug 2022 19:35:39 +0200
Corinna Vinschen wrote:
> On Aug 11 21:18, Takashi Yano wrote:
> > On Thu, 11 Aug 2022 11:29:28 +1000
> > Tony Cook wrote:
> > > Hello everyone,
> > > 
> > > While tracking down a crash in development versions of perl the boostrap
> > > miniperl executable was crashing early in the build process:
> > > [...]
> > 
> > I looked into this problem and found the access violation
> > occurs at:
> > newlib/libc/locale/newlocale.c
> > @@ 188,7 @@ _newlocale_r (struct _reent *p, int category_mask, const char *locale,
> > 	if (tmp_locale.lc_cat[i].buf == (const void *) -1)
> > 	  {
> > 	    tmp_locale.lc_cat[i].buf = base->lc_cat[i].buf;
> > 	    base->lc_cat[i].ptr = base->lc_cat[i].buf = NULL; <-- Here!!!
> > 	  }
> > #endif /* __HAVE_LOCALE_INFO__ */
> >       _freelocale_r (p, base);
> > 
> > This is because
> > locale_t st = newlocale(LC_ALL_MASK, "C", (locale_t)0);
> > returns
> >   extern const struct __locale_t __C_locale;
> >   return (struct __locale_t *) &__C_locale;
> > , which is in the const area that cannot be modified.
> > 
> > This seems to be a newlib bug.
> > 
> > I also found following patch solves the issue.
> > 
> > diff --git a/newlib/libc/locale/newlocale.c b/newlib/libc/locale/newlocale.c
> > index 0789d5fd9..1974665ec 100644
> > --- a/newlib/libc/locale/newlocale.c
> > +++ b/newlib/libc/locale/newlocale.c
> > @@ -108,10 +108,12 @@ _newlocale_r (struct _reent *p, int category_mask, const char *locale,
> >      }
> >    /* If the new locale is supposed to be all default locale, just return
> >       a pointer to the default locale. */
> > +#if 0
> >    if ((!base && category_mask == 0)
> >        || (category_mask == LC_VALID_MASK
> >  	  && (!strcmp (locale, "C") || !strcmp (locale, "POSIX"))))
> >      return __get_C_locale ();
> > +#endif
> >    /* Start with setting all values to the default locale values. */
> >    tmp_locale = *__get_C_locale ();
> >    /* Fill out new category strings. */
> 
> I think the right thing to do is to avoid freeing this data, if the base
> locale is the C locale.  I sent a patch to cygwin-patches for review.
> Can you please take a look?

LGTM. Thanks!

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>