From patchwork Tue Sep 25 07:41:13 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Willi X-Patchwork-Id: 10613579 X-Patchwork-Delegate: johannes@sipsolutions.net Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E6C7C1390 for ; Tue, 25 Sep 2018 07:41:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DBF9929868 for ; Tue, 25 Sep 2018 07:41:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CEFD529870; Tue, 25 Sep 2018 07:41:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 42A4129868 for ; Tue, 25 Sep 2018 07:41:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728904AbeIYNri (ORCPT ); Tue, 25 Sep 2018 09:47:38 -0400 Received: from sitav-80046.hsr.ch ([152.96.80.46]:57408 "EHLO mail.strongswan.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728751AbeIYNri (ORCPT ); Tue, 25 Sep 2018 09:47:38 -0400 Received: from book.wlp.is (unknown [185.12.128.225]) by mail.strongswan.org (Postfix) with ESMTPSA id 9CBF740A78; Tue, 25 Sep 2018 09:41:27 +0200 (CEST) From: Martin Willi To: Johannes Berg Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Benjamin Beichler Subject: [PATCH 1/3] mac80211_hwsim: fix locking when iterating radios during ns exit Date: Tue, 25 Sep 2018 09:41:13 +0200 Message-Id: <20180925074115.18169-2-martin@strongswan.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180925074115.18169-1-martin@strongswan.org> References: <20180925074115.18169-1-martin@strongswan.org> Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The cleanup of radios during namespace exit has recently been reworked to directly delete a radio while temporarily releasing the spinlock, fixing a race condition between the work-queue execution and namespace exits. However, the temporary unlock allows unsafe modifications on the iterated list, resulting in a potential crash when continuing the iteration of additional radios. Move radios about to destroy to a temporary list, and clean that up after releasing the spinlock once iteration is complete. Fixes: 8cfd36a0b53a ("mac80211_hwsim: fix use-after-free bug in hwsim_exit_net") Signed-off-by: Martin Willi --- drivers/net/wireless/mac80211_hwsim.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index f3863101af78..8c76e9a3499a 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -3642,6 +3642,7 @@ static __net_init int hwsim_init_net(struct net *net) static void __net_exit hwsim_exit_net(struct net *net) { struct mac80211_hwsim_data *data, *tmp; + LIST_HEAD(list); spin_lock_bh(&hwsim_radio_lock); list_for_each_entry_safe(data, tmp, &hwsim_radios, list) { @@ -3652,17 +3653,19 @@ static void __net_exit hwsim_exit_net(struct net *net) if (data->netgroup == hwsim_net_get_netgroup(&init_net)) continue; - list_del(&data->list); + list_move(&data->list, &list); rhashtable_remove_fast(&hwsim_radios_rht, &data->rht, hwsim_rht_params); hwsim_radios_generation++; - spin_unlock_bh(&hwsim_radio_lock); + } + spin_unlock_bh(&hwsim_radio_lock); + + list_for_each_entry_safe(data, tmp, &list, list) { + list_del(&data->list); mac80211_hwsim_del_radio(data, wiphy_name(data->hw->wiphy), NULL); - spin_lock_bh(&hwsim_radio_lock); } - spin_unlock_bh(&hwsim_radio_lock); ida_simple_remove(&hwsim_netgroup_ida, hwsim_net_get_netgroup(net)); }