From patchwork Fri Feb 5 00:36:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 12069063 X-Patchwork-Delegate: kuba@kernel.org 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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 00368C433E9 for ; Fri, 5 Feb 2021 00:48:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C684364DF8 for ; Fri, 5 Feb 2021 00:48:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232228AbhBEArr (ORCPT ); Thu, 4 Feb 2021 19:47:47 -0500 Received: from mx2.suse.de ([195.135.220.15]:38218 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232198AbhBEArm (ORCPT ); Thu, 4 Feb 2021 19:47:42 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 9246AAE3F; Fri, 5 Feb 2021 00:47:00 +0000 (UTC) From: NeilBrown To: Andrew Morton , Alexander Viro , Vlad Yasevich , Neil Horman , Marcelo Ricardo Leitner Date: Fri, 05 Feb 2021 11:36:30 +1100 Subject: [PATCH 3/3] net: fix iteration for sctp transport seq_files Cc: Xin Long , linux-kernel@vger.kernel.org, "David S. Miller" , linux-sctp@vger.kernel.org, netdev@vger.kernel.org Message-ID: <161248539022.21478.17038123892954492263.stgit@noble1> In-Reply-To: <161248518659.21478.2484341937387294998.stgit@noble1> References: <161248518659.21478.2484341937387294998.stgit@noble1> User-Agent: StGit/0.23 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org The sctp transport seq_file iterators take a reference to the transport in the ->start and ->next functions and releases the reference in the ->show function. The preferred handling for such resources is to release them in the subsequent ->next or ->stop function call. Since Commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") there is no guarantee that ->show will be called after ->next, so this function can now leak references. So move the sctp_transport_put() call to ->next and ->stop. Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") Reported-by: Xin Long Signed-off-by: NeilBrown Acked-by: Marcelo Ricardo Leitner --- net/sctp/proc.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/net/sctp/proc.c b/net/sctp/proc.c index f7da88ae20a5..982a87b3e11f 100644 --- a/net/sctp/proc.c +++ b/net/sctp/proc.c @@ -215,6 +215,12 @@ static void sctp_transport_seq_stop(struct seq_file *seq, void *v) { struct sctp_ht_iter *iter = seq->private; + if (v && v != SEQ_START_TOKEN) { + struct sctp_transport *transport = v; + + sctp_transport_put(transport); + } + sctp_transport_walk_stop(&iter->hti); } @@ -222,6 +228,12 @@ static void *sctp_transport_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct sctp_ht_iter *iter = seq->private; + if (v && v != SEQ_START_TOKEN) { + struct sctp_transport *transport = v; + + sctp_transport_put(transport); + } + ++*pos; return sctp_transport_get_next(seq_file_net(seq), &iter->hti); @@ -277,8 +289,6 @@ static int sctp_assocs_seq_show(struct seq_file *seq, void *v) sk->sk_rcvbuf); seq_printf(seq, "\n"); - sctp_transport_put(transport); - return 0; } @@ -354,8 +364,6 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v) seq_printf(seq, "\n"); } - sctp_transport_put(transport); - return 0; }