On Fri, Nov 16, 2018 at 2:22 AM Marcelo Ricardo Leitner
<marcelo.leitner@xxxxxxxxx> wrote:
>
> On Thu, Nov 15, 2018 at 07:14:28PM +0800, Xin Long wrote:
> > As rfc7496#section4.5 says about SCTP_PR_SUPPORTED:
> >
> > This socket option allows the enabling or disabling of the
> > negotiation of PR-SCTP support for future associations. For existing
> > associations, it allows one to query whether or not PR-SCTP support
> > was negotiated on a particular association.
> >
> > It means only sctp sock's prsctp_enable can be set.
> >
> > Note that for the limitation of SCTP_{CURRENT|ALL}_ASSOC, we will
> > add it when introducing SCTP_{FUTURE|CURRENT|ALL}_ASSOC for linux
> > sctp in another patchset.
> >
> > Fixes: 28aa4c26fce2 ("sctp: add SCTP_PR_SUPPORTED on sctp sockopt")
> > Reported-by: Ying Xu <yinxu@xxxxxxxxxx>
> > Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> > ---
> > net/sctp/socket.c | 13 +++----------
> > 1 file changed, 3 insertions(+), 10 deletions(-)
> >
> > diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> > index 739f3e5..e9b8232 100644
> > --- a/net/sctp/socket.c
> > +++ b/net/sctp/socket.c
> > @@ -3940,7 +3940,6 @@ static int sctp_setsockopt_pr_supported(struct sock *sk,
> > unsigned int optlen)
> > {
> > struct sctp_assoc_value params;
> > - struct sctp_association *asoc;
> > int retval = -EINVAL;
> >
> > if (optlen != sizeof(params))
> > @@ -3951,16 +3950,10 @@ static int sctp_setsockopt_pr_supported(struct sock *sk,
> > goto out;
> > }
> >
> > - asoc = sctp_id2assoc(sk, params.assoc_id);
> > - if (asoc) {
> > - asoc->prsctp_enable = !!params.assoc_value;
> > - } else if (!params.assoc_id) {
> > - struct sctp_sock *sp = sctp_sk(sk);
> > -
> > - sp->ep->prsctp_enable = !!params.assoc_value;
> > - } else {
> > + if (sctp_style(sk, UDP) && sctp_id2assoc(sk, params.assoc_id))
I got this semantic from BSD's SCTP_PR_SUPPORTED sockopt:
SCTP_FIND_STCB(inp, stcb, av->assoc_id);
if (stcb) {
SCTP_LTRACE_ERR_RET(...);
error = EINVAL;
SCTP_TCB_UNLOCK(stcb);
} else {
...
}
>
> This would allow using a non-existent assoc id on UDP-style sockets to
> set it at the socket, which is not expected. It should be more like:
>
> + if (sctp_style(sk, UDP) && params.assoc_id)
This way is more strict, but it seems reasonable.
When a user sets params.assoc_id for UDP type socket, it should be
thought as he WANTs to apply this on assoc, which is not allowed here.
