Re: [PATCH 4.14 024/119] sctp: change sctp_prot .no_autobind with true

[Sasha Levin]

On Thu, Oct 31, 2019 at 05:14:15PM +0800, Xin Long wrote:
> On Thu, Oct 31, 2019 at 3:54 PM Rantala, Tommi T. (Nokia - FI/Espoo)
> <tommi.t.rantala@xxxxxxxxx> wrote:
> > On Sun, 2019-10-27 at 22:00 +0100, Greg Kroah-Hartman wrote:
> > > From: Xin Long <lucien.xin@xxxxxxxxx>
> > >
> > > [ Upstream commit 63dfb7938b13fa2c2fbcb45f34d065769eb09414 ]
> > >
> > > syzbot reported a memory leak:
> > >
> > >   BUG: memory leak, unreferenced object 0xffff888120b3d380 (size 64):
> > >   backtrace:
> > >
> > >     [...] slab_alloc mm/slab.c:3319 [inline]
> > >     [...] kmem_cache_alloc+0x13f/0x2c0 mm/slab.c:3483
> > >     [...] sctp_bucket_create net/sctp/socket.c:8523 [inline]
> > >     [...] sctp_get_port_local+0x189/0x5a0 net/sctp/socket.c:8270
> > >     [...] sctp_do_bind+0xcc/0x200 net/sctp/socket.c:402
> > >     [...] sctp_bindx_add+0x4b/0xd0 net/sctp/socket.c:497
> > >     [...] sctp_setsockopt_bindx+0x156/0x1b0 net/sctp/socket.c:1022
> > >     [...] sctp_setsockopt net/sctp/socket.c:4641 [inline]
> > >     [...] sctp_setsockopt+0xaea/0x2dc0 net/sctp/socket.c:4611
> > >     [...] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3147
> > >     [...] __sys_setsockopt+0x10f/0x220 net/socket.c:2084
> > >     [...] __do_sys_setsockopt net/socket.c:2100 [inline]
> > >
> > > It was caused by when sending msgs without binding a port, in the path:
> > > inet_sendmsg() -> inet_send_prepare() -> inet_autobind() ->
> > > .get_port/sctp_get_port(), sp->bind_hash will be set while bp->port is
> > > not. Later when binding another port by sctp_setsockopt_bindx(), a new
> > > bucket will be created as bp->port is not set.
> > >
> > > sctp's autobind is supposed to call sctp_autobind() where it does all
> > > things including setting bp->port. Since sctp_autobind() is called in
> > > sctp_sendmsg() if the sk is not yet bound, it should have skipped the
> > > auto bind.
> > >
> > > THis patch is to avoid calling inet_autobind() in inet_send_prepare()
> > > by changing sctp_prot .no_autobind with true, also remove the unused
> > > .get_port.
> >
> > Hi,
> >
> > I'm seeing SCTP oops in 4.14.151, reproducible easily with iperf:
> >
> > # iperf3 -s -1 &
> > # iperf3 -c localhost --sctp
> >
> > This patch was also included in 4.19.81, but there it seems to be working
> > fine.
> >
> > Any ideas if this patch is valid for 4.14, or what's missing in 4.14 to
> > make this work?
> pls get this commit into 4.14, which has been in 4.19:
>
> commit 644fbdeacf1d3edd366e44b8ba214de9d1dd66a9
> Author: Xin Long <lucien.xin@xxxxxxxxx>
> Date:   Sun May 20 16:39:10 2018 +0800
>
>    sctp: fix the issue that flags are ignored when using kernel_connect

Care to send a backport?

--
Thanks,
Sasha