[PATCH 4/4] pam_lastlog: Fix potential segfault when terminal_line is NULL.

[Robin Hack]

Hi Tomas.

You are right. Thanks.

On Wed, Aug 13, 2014 at 03:07:53PM +0200, Tomas Mraz wrote:
> On St, 2014-08-13 at 14:27 +0200, Robin Hack wrote:
> > ---
> >  modules/pam_lastlog/pam_lastlog.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/modules/pam_lastlog/pam_lastlog.c b/modules/pam_lastlog/pam_lastlog.c
> > index 50d33e4..1bd6d65 100644
> > --- a/modules/pam_lastlog/pam_lastlog.c
> > +++ b/modules/pam_lastlog/pam_lastlog.c
> > @@ -176,12 +176,16 @@ get_tty(pam_handle_t *pamh)
> >      if (pam_get_item(pamh, PAM_TTY, &void_terminal_line) != PAM_SUCCESS
> >  	|| void_terminal_line == NULL) {
> >  	terminal_line = DEFAULT_TERM;
> > +    D(("terminal = %s", terminal_line));
> > +    return terminal_line;
> >      } else {
> >  	terminal_line = void_terminal_line;
> > +    D(("terminal = %s", terminal_line));
> > +    return terminal_line;
> >      }
> >      if (!strncmp("/dev/", terminal_line, 5)) {
> > -	/* strip leading "/dev/" from tty. */
> > -	terminal_line += 5;
> > +    /* strip leading "/dev/" from tty. */
> > +    terminal_line += 5;
> >      }
> >      D(("terminal = %s", terminal_line));
> >      return terminal_line;
> 
> I do not understand the purpose of this patch. The terminal_line cannot
> be NULL because in case the pam_get_item fails or returns NULL in
> void_terminal_line the DEFAULT_TERM constant is used.
> 
> -- 
> Tomas Mraz
> No matter how far down the wrong road you've gone, turn back.
>                                               Turkish proverb
> (You'll never know whether the road is wrong though.)
> 
> 
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