Re: [hurd, commited] hurd: Use __trivfs_server_name instead of trivfs_server_name

[Samuel Thibault]

Florian Weimer, le sam. 01 janv. 2022 18:27:49 +0100, a ecrit:
> > @@ -33,14 +33,14 @@ __getrandom (void *buffer, size_t length, unsigned int 
> > flags)
> >    size_t amount_read;
> >    int fd;
> >  
> > -  if (&trivfs_server_name && trivfs_server_name
> > -      && trivfs_server_name[0] == 'r'
> > -      && trivfs_server_name[1] == 'a'
> > -      && trivfs_server_name[2] == 'n'
> > -      && trivfs_server_name[3] == 'd'
> > -      && trivfs_server_name[4] == 'o'
> > -      && trivfs_server_name[5] == 'm'
> > -      && trivfs_server_name[6] == '\0')
> > +  if (&__trivfs_server_name && __trivfs_server_name
> > +      && __trivfs_server_name[0] == 'r'
> > +      && __trivfs_server_name[1] == 'a'
> > +      && __trivfs_server_name[2] == 'n'
> > +      && __trivfs_server_name[3] == 'd'
> > +      && __trivfs_server_name[4] == 'o'
> > +      && __trivfs_server_name[5] == 'm'
> > +      && __trivfs_server_name[6] == '\0')
> >      /* We are random, don't try to read ourselves!  */
> >      return length;
> 
> How does this work?  It's a new synbol name, so there's no definition,
> so the weak reference is always null.

It is peeking it from the program.

Basically the problem is that the random translator uses glibc, whose
malloc implementation started using /dev/random in glibc 2.34, thus
reading itself.

Samuel