Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932334AbdGCNlF (ORCPT ); Mon, 3 Jul 2017 09:41:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35584 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755134AbdGCNlD (ORCPT ); Mon, 3 Jul 2017 09:41:03 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xin Long , "David S. Miller" Subject: [PATCH 4.9 017/172] sctp: return next obj by passing pos + 1 into sctp_transport_get_idx Date: Mon, 3 Jul 2017 15:33:17 +0200 Message-Id: <20170703133415.057244917@linuxfoundation.org> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170703133414.260777365@linuxfoundation.org> References: <20170703133414.260777365@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1736 Lines: 46 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long [ Upstream commit 988c7322116970696211e902b468aefec95b6ec4 ] In sctp_for_each_transport, pos is used to save how many objs it has dumped. Now it gets the last obj by sctp_transport_get_idx, then gets the next obj by sctp_transport_get_next. The issue is that in the meanwhile if some objs in transport hashtable are removed and the objs nums are less than pos, sctp_transport_get_idx would return NULL and hti.walker.tbl is NULL as well. At this moment it should stop hti, instead of continue getting the next obj. Or it would cause a NULL pointer dereference in sctp_transport_get_next. This patch is to pass pos + 1 into sctp_transport_get_idx to get the next obj directly, even if pos > objs nums, it would return NULL and stop hti. Fixes: 626d16f50f39 ("sctp: export some apis or variables for sctp_diag and reuse some for proc") Signed-off-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sctp/socket.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -4506,9 +4506,8 @@ int sctp_for_each_transport(int (*cb)(st if (err) return err; - sctp_transport_get_idx(net, &hti, pos); - obj = sctp_transport_get_next(net, &hti); - for (; obj && !IS_ERR(obj); obj = sctp_transport_get_next(net, &hti)) { + obj = sctp_transport_get_idx(net, &hti, pos + 1); + for (; !IS_ERR_OR_NULL(obj); obj = sctp_transport_get_next(net, &hti)) { struct sctp_transport *transport = obj; if (!sctp_transport_hold(transport))