On Fri, 2014-01-10 at 16:08 -0500, Eric Paris wrote:
> If you know the buf len, you can just use audit_log_n_untrusted_string()
> I think....

admittedly audit_log_n_untrusted_string() will log ALL of n.  So you
could use strnlen() as the argument to audit_log_n_untrusted_string()
(or create another helper, I don't care)

-Eric
> 
> On Tue, 2014-01-07 at 12:44 -0800, William Roberts wrote:
> > Signed-off-by: William Roberts <[email protected]>
> > ---
> >  kernel/auditsc.c |   19 +++++++++++++++----
> >  1 file changed, 15 insertions(+), 4 deletions(-)
> > 
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index a4c2003..9ba1f2a 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -1292,9 +1292,20 @@ static void audit_log_cmdline(struct audit_buffer 
> > *ab, struct task_struct *tsk,
> >             if (!buf)
> >                     goto out;
> >             res = get_cmdline(tsk, buf, PATH_MAX);
> > -           /* Ensure NULL terminated */
> > -           if (buf[res-1] != '\0')
> > -                   buf[res-1] = '\0';
> > +           if (res == 0) {
> > +                   kfree(buf);
> > +                   goto out;
> > +           }
> > +           /*
> > +            * Ensure NULL terminated but don't clobber the end
> > +            * unless the buffer is full. Worst case you end up
> > +            * with 2 null bytes ending it. By doing it this way
> > +            * one avoids additional branching. One checking if the
> > +            * end is null and another to check if their should be
> > +            * an increment before setting the null byte.
> > +            */
> > +           res += res < PATH_MAX;
> > +           buf[res-1] = '\0';
> >             context->cmdline = buf;
> >     }
> >     msg = context->cmdline;
> > @@ -1333,8 +1344,8 @@ static void audit_log_exit(struct audit_context 
> > *context, struct task_struct *ts
> >                      context->name_count);
> >  
> >     audit_log_task_info(ab, tsk);
> > -   audit_log_cmdline(ab, tsk, context);
> >     audit_log_key(ab, context->filterkey);
> > +   audit_log_cmdline(ab, tsk, context);
> >     audit_log_end(ab);
> >  
> >     for (aux = context->aux; aux; aux = aux->next) {
> 


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