From: Phil Sutter
> Sent: 18 August 2017 12:16
> On Fri, Aug 18, 2017 at 09:30:35AM +0000, David Laight wrote:
> > From: Phil Sutter
> > > Sent: 17 August 2017 18:10
> > > The later check for 'k[0] != 0' requires a non-empty filter name,
> > > otherwise NULL pointer dereference in 'q' might happen.
> > >
> > > Signed-off-by: Phil Sutter <p...@nwl.cc>
> > > ---
> > > tc/tc_filter.c | 3 +++
> > > 1 file changed, 3 insertions(+)
> > >
> > > diff --git a/tc/tc_filter.c b/tc/tc_filter.c
> > > index b13fb9185d4fd..a799edb35886d 100644
> > > --- a/tc/tc_filter.c
> > > +++ b/tc/tc_filter.c
> > > @@ -412,6 +412,9 @@ static int tc_filter_get(int cmd, unsigned int flags,
> > > int argc, char **argv)
> > > usage();
> > > return 0;
> > > } else {
> > > + if (!strlen(*argv))
> > > + invarg("invalid filter name", *argv);
> >
> > That is nearly as bad as:
> > p[strlen(p)] = 0;
>
> Hey, it's not impossible! I could call tc like so:
>
> | # tc filter get protocol ip prio 1 ""
You missed the point. Just check **argv there is no need to
determine the length just to check it is non-zero.
David
