Re: [PATCH] locale: don't crash if locale-archive is an empty file

[Aurelien Jarno <aurelien at aurel32 dot net>]

On Fri, Nov 29, 2013 at 11:36:35AM -0500, Carlos O'Donell wrote:
> On 11/29/2013 10:39 AM, Aurelien Jarno wrote:
> > In case of power failure followed by filesystem issues locale-archive
> > can end-up containing all zeros. In that case all calls to setlocale()
> > generate a SIGFPE. This renders a system with a default non-C locale
> > unbootable.
> > 
> > Avoid this by ignoring the locale instead of generating a SIGFPE.
> > ---
> >  locale/loadarchive.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > 2013-11-29  Aurelien Jarno <aurelien@aurel32.net>
> > 
> > 	* locale/loadarchive.c (_nl_load_locale_from_archive): Avoid
> > 	division by 0.
> > 
> > diff --git a/locale/loadarchive.c b/locale/loadarchive.c
> > index 70136dc..7cfc498 100644
> > --- a/locale/loadarchive.c
> > +++ b/locale/loadarchive.c
> > @@ -274,6 +274,10 @@ _nl_load_locale_from_archive (int category, const char **namep)
> >    namehashtab = (struct namehashent *) ((char *) head
> >  					+ head->namehash_offset);
> >  
> > +  /* Avoid division by 0 if the file is corrupted.  */
> > +  if (__builtin_expect (head->namehash_size == 0, 0))
> > +    goto close_and_out;
> > +
> >    idx = hval % head->namehash_size;
> >    incr = 1 + hval % (head->namehash_size - 2);
> >  
> > 
> 
> How did you test this?

I fetched a broken locale-archive from [1] and set the environment
variables LANG="en_IN" and LANGUAGE="en_IN:en" (though I have been able
to reproduce with my default locales setting). Then all coreutils
commands started to SIGFPE (ls, mount, su, grep, etc.).

In installed the fixed version of the libc, and all commands started
to work again.

Cheers,
Aurelien

[1] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=730336

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net