On Wed, Nov 14, 2018 at 2:16 AM Neil Horman <nhorman@xxxxxxxxxxxxx> wrote:
>
> On Tue, Nov 13, 2018 at 02:24:53PM +0800, Xin Long wrote:
> >
> > /* Default Peer Address Parameters. These defaults can
> > * be modified via SCTP_PEER_ADDR_PARAMS
> > @@ -5267,14 +5274,24 @@ static int sctp_getsockopt_disable_fragments(struct sock *sk, int len,
> > static int sctp_getsockopt_events(struct sock *sk, int len, char __user *optval,
> > int __user *optlen)
> > {
> > + struct sctp_event_subscribe subscribe;
> > + __u8 *sn_type = (__u8 *)&subscribe;
> > + int i;
> > +
> > if (len == 0)
> > return -EINVAL;
> > if (len > sizeof(struct sctp_event_subscribe))
> > len = sizeof(struct sctp_event_subscribe);
> > if (put_user(len, optlen))
> > return -EFAULT;
> > - if (copy_to_user(optval, &sctp_sk(sk)->subscribe, len))
> > +
> > + for (i = 0; i <= len; i++)
> > + sn_type[i] = sctp_ulpevent_type_enabled(sctp_sk(sk)->subscribe,
> > + SCTP_SN_TYPE_BASE + i);
> > +
> This seems like an off by one error. sctp_event_subscribe has N bytes in it (1
> byte for each event), meaning that that events 0-(N-1) are subscribable.
> Iterating this loop imples that you are going to check N events, overrunning the
> sctp_event_subscribe struct.
you're right, thanks.
>
> Neil
>
> >
