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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 85AEDC433DF for ; Tue, 26 May 2020 18:57:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5BBD32084C for ; Tue, 26 May 2020 18:57:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590519440; bh=HS4dO0GbWK+cbuD9M/sp6XBeeNJS7vmNUhMjPvYwcpM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=t1hSrfowijvB+v7Yh3omuNew1eBt5k3i3oFJQN2U/Yknotfa6IjUQQBVeiazBRscI 6sI5kNMaXO3cNIgbC5l7rmD2fY/7TSIHt/LxRGGBxtJEEN2LpAgnH7HbBOz6MSRElr 4B3vPDf5aORknD6PgwifK7T0ELK1WUwZot3dRdbM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390072AbgEZS5T (ORCPT ); Tue, 26 May 2020 14:57:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:50362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390024AbgEZS5M (ORCPT ); Tue, 26 May 2020 14:57:12 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 17E582084C; Tue, 26 May 2020 18:57:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590519431; bh=HS4dO0GbWK+cbuD9M/sp6XBeeNJS7vmNUhMjPvYwcpM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VVX9Y6POQKSjBFfM1kmdnfBX+DdFEudoDC2sr1612Ebb1cdIHq83Dh1blYCKEV0ns WaXU8xTPRn7X7blBYceSZXkgx6yHUuh7mLFxk+bf0kGNqSPD4zo2ZLLCm85AMeyoDN VdAg3gMGHGpzyqhsKcVqmCZvFyKJbqjYuu36QUig= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, greg@kroah.com Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guillaume Nault , "David S. Miller" , Giuliano Procida Subject: [PATCH 4.4 48/65] l2tp: initialise sessions refcount before making it reachable Date: Tue, 26 May 2020 20:53:07 +0200 Message-Id: <20200526183922.661550701@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200526183905.988782958@linuxfoundation.org> References: <20200526183905.988782958@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guillaume Nault commit 9ee369a405c57613d7c83a3967780c3e30c52ecc upstream. Sessions must be fully initialised before calling l2tp_session_add_to_tunnel(). Otherwise, there's a short time frame where partially initialised sessions can be accessed by external users. Backporting Notes l2tp_core.c: moving code that had been converted from atomic to refcount_t by an earlier change (which isn't being included in this patch series). Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Giuliano Procida Signed-off-by: Greg Kroah-Hartman --- net/l2tp/l2tp_core.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1853,6 +1853,8 @@ struct l2tp_session *l2tp_session_create l2tp_session_set_header_len(session, tunnel->version); + l2tp_session_inc_refcount(session); + err = l2tp_session_add_to_tunnel(tunnel, session); if (err) { kfree(session); @@ -1860,10 +1862,6 @@ struct l2tp_session *l2tp_session_create return ERR_PTR(err); } - /* Bump the reference count. The session context is deleted - * only when this drops to zero. - */ - l2tp_session_inc_refcount(session); l2tp_tunnel_inc_refcount(tunnel); /* Ensure tunnel socket isn't deleted */