svn commit: r305383 - head/sys/sys

[Mateusz Guzik]

On Sun, Sep 04, 2016 at 09:00:38AM -0700, Conrad Meyer wrote:
> Do you know which revision this was introduced (i.e. what revision
> range should be avoided)?  The most relevant commit seems to be
> r305093 but I'm not sure how that would have broken this (nothing in
> that diff was checking fde_file before).
> 

The problem was present since r305093 to this very commit.

The problem affects weird programs which do F_GETFD to see if they got
given fd installed, like bash.

Prior to r305093 they would get EBADF. But due to incorrect test in
fdeget_locked, they would get 0 instead.

> Best,
> Conrad
> 
> On Sun, Sep 4, 2016 at 6:31 AM, Mateusz Guzik <mjg at freebsd.org> wrote:
> > Author: mjg
> > Date: Sun Sep  4 13:31:57 2016
> > New Revision: 305383
> > URL: https://svnweb.freebsd.org/changeset/base/305383
> >
> > Log:
> >   fd: fix up fdeget_file
> >
> >   It was supposed to return NULL if a fp is not installed.
> >
> >   Facepalm-by: mjg
> >
> > Modified:
> >   head/sys/sys/filedesc.h
> >
> > Modified: head/sys/sys/filedesc.h
> > ==============================================================================
> > --- head/sys/sys/filedesc.h     Sun Sep  4 12:22:14 2016        (r305382)
> > +++ head/sys/sys/filedesc.h     Sun Sep  4 13:31:57 2016        (r305383)
> > @@ -210,13 +210,18 @@ fget_locked(struct filedesc *fdp, int fd
> >  static __inline struct filedescent *
> >  fdeget_locked(struct filedesc *fdp, int fd)
> >  {
> > +       struct filedescent *fde;
> >
> >         FILEDESC_LOCK_ASSERT(fdp);
> >
> >         if (fd < 0 || fd > fdp->fd_lastfile)
> >                 return (NULL);
> >
> > -       return (&fdp->fd_ofiles[fd]);
> > +       fde = &fdp->fd_ofiles[fd];
> > +       if (fde->fde_file == NULL)
> > +               return (NULL);
> > +
> > +       return (fde);
> >  }
> >
> >  static __inline bool
> >

-- 
Mateusz Guzik <mjguzik gmail.com>