From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C93CC2D0C0 for ; Mon, 23 Dec 2019 12:46:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 754DD20709 for ; Mon, 23 Dec 2019 12:46:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726733AbfLWMqY (ORCPT ); Mon, 23 Dec 2019 07:46:24 -0500 Received: from charlotte.tuxdriver.com ([70.61.120.58]:42494 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726663AbfLWMqX (ORCPT ); Mon, 23 Dec 2019 07:46:23 -0500 Received: from 2606-a000-111b-43ee-0000-0000-0000-115f.inf6.spectrum.com ([2606:a000:111b:43ee::115f] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from ) id 1ijN6B-0005cj-N3; Mon, 23 Dec 2019 07:46:19 -0500 Date: Mon, 23 Dec 2019 07:46:09 -0500 From: Neil Horman To: Marcelo Ricardo Leitner Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org, Xin Long , syzbot , syzkaller-bugs@googlegroups.com Subject: Re: [PATCH net] sctp: fix err handling of stream initialization Message-ID: <20191223124609.GA30462@hmswarspite.think-freely.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Dec 20, 2019 at 03:03:44PM -0300, Marcelo Ricardo Leitner wrote: > The fix on 951c6db954a1 fixed the issued reported there but introduced > another. When the allocation fails within sctp_stream_init() it is > okay/necessary to free the genradix. But it is also called when adding > new streams, from sctp_send_add_streams() and > sctp_process_strreset_addstrm_in() and in those situations it cannot > just free the genradix because by then it is a fully operational > association. > > The fix here then is to only free the genradix in sctp_stream_init() > and on those other call sites move on with what it already had and let > the subsequent error handling to handle it. > > Tested with the reproducers from this report and the previous one, > with lksctp-tools and sctp-tests. > > Reported-by: syzbot+9a1bc632e78a1a98488b@syzkaller.appspotmail.com > Fixes: 951c6db954a1 ("sctp: fix memleak on err handling of stream initialization") > Signed-off-by: Marcelo Ricardo Leitner > --- > net/sctp/stream.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/net/sctp/stream.c b/net/sctp/stream.c > index 6a30392068a04bfcefcb14c3d7f13fc092d59cd3..c1a100d2fed39c2d831487e05fcbf5e8d507d470 100644 > --- a/net/sctp/stream.c > +++ b/net/sctp/stream.c > @@ -84,10 +84,8 @@ static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt, > return 0; > > ret = genradix_prealloc(&stream->out, outcnt, gfp); > - if (ret) { > - genradix_free(&stream->out); > + if (ret) > return ret; > - } > > stream->outcnt = outcnt; > return 0; > @@ -102,10 +100,8 @@ static int sctp_stream_alloc_in(struct sctp_stream *stream, __u16 incnt, > return 0; > > ret = genradix_prealloc(&stream->in, incnt, gfp); > - if (ret) { > - genradix_free(&stream->in); > + if (ret) > return ret; > - } > > stream->incnt = incnt; > return 0; > @@ -123,7 +119,7 @@ int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt, > * a new one with new outcnt to save memory if needed. > */ > if (outcnt == stream->outcnt) > - goto in; > + goto handle_in; > > /* Filter out chunks queued on streams that won't exist anymore */ > sched->unsched_all(stream); > @@ -132,24 +128,28 @@ int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt, > > ret = sctp_stream_alloc_out(stream, outcnt, gfp); > if (ret) > - goto out; > + goto out_err; > > for (i = 0; i < stream->outcnt; i++) > SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN; > > -in: > +handle_in: > sctp_stream_interleave_init(stream); > if (!incnt) > goto out; > > ret = sctp_stream_alloc_in(stream, incnt, gfp); > - if (ret) { > - sched->free(stream); > - genradix_free(&stream->out); > - stream->outcnt = 0; > - goto out; > - } > + if (ret) > + goto in_err; > + > + goto out; > > +in_err: > + sched->free(stream); > + genradix_free(&stream->in); > +out_err: > + genradix_free(&stream->out); Isn't this effectively a double free in the fall through case? Neil > + stream->outcnt = 0; > out: > return ret; > } > -- > 2.23.0 > >