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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B40A3C4167E for ; Sun, 17 Oct 2021 21:01:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E27960EB9 for ; Sun, 17 Oct 2021 21:01:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344615AbhJQVEH (ORCPT ); Sun, 17 Oct 2021 17:04:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344613AbhJQVEF (ORCPT ); Sun, 17 Oct 2021 17:04:05 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07917C061769 for ; Sun, 17 Oct 2021 14:01:55 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mcDI1-0000Fx-8c for netdev@vger.kernel.org; Sun, 17 Oct 2021 23:01:53 +0200 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id F2B06695EED for ; Sun, 17 Oct 2021 21:01:47 +0000 (UTC) Received: from hardanger.blackshift.org (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id 91AAB695EAF; Sun, 17 Oct 2021 21:01:44 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id 6e17d583; Sun, 17 Oct 2021 21:01:43 +0000 (UTC) From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org, kernel@pengutronix.de, Ziyang Xuan , stable@vger.kernel.org, syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com, Oleksij Rempel , Marc Kleine-Budde Subject: [PATCH net 02/11] can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv Date: Sun, 17 Oct 2021 23:01:33 +0200 Message-Id: <20211017210142.2108610-3-mkl@pengutronix.de> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211017210142.2108610-1-mkl@pengutronix.de> References: <20211017210142.2108610-1-mkl@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ziyang Xuan It will trigger UAF for rx_kref of j1939_priv as following. cpu0 cpu1 j1939_sk_bind(socket0, ndev0, ...) j1939_netdev_start j1939_sk_bind(socket1, ndev0, ...) j1939_netdev_start j1939_priv_set j1939_priv_get_by_ndev_locked j1939_jsk_add ..... j1939_netdev_stop kref_put_lock(&priv->rx_kref, ...) kref_get(&priv->rx_kref, ...) REFCOUNT_WARN("addition on 0;...") ==================================================== refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 Call Trace: j1939_netdev_start+0x68b/0x920 j1939_sk_bind+0x426/0xeb0 ? security_socket_bind+0x83/0xb0 The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to protect. Fixes: 9d71dd0c70099 ("can: add support of SAE J1939 protocol") Link: https://lore.kernel.org/all/20210926104757.2021540-1-william.xuanziyang@huawei.com Cc: stable@vger.kernel.org Reported-by: syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan Acked-by: Oleksij Rempel Signed-off-by: Marc Kleine-Budde --- net/can/j1939/main.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index 08c8606cfd9c..9bc55ecb37f9 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -249,11 +249,14 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) struct j1939_priv *priv, *priv_new; int ret; - priv = j1939_priv_get_by_ndev(ndev); + spin_lock(&j1939_netdev_lock); + priv = j1939_priv_get_by_ndev_locked(ndev); if (priv) { kref_get(&priv->rx_kref); + spin_unlock(&j1939_netdev_lock); return priv; } + spin_unlock(&j1939_netdev_lock); priv = j1939_priv_create(ndev); if (!priv) @@ -269,10 +272,10 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) /* Someone was faster than us, use their priv and roll * back our's. */ + kref_get(&priv_new->rx_kref); spin_unlock(&j1939_netdev_lock); dev_put(ndev); kfree(priv); - kref_get(&priv_new->rx_kref); return priv_new; } j1939_priv_set(ndev, priv); -- 2.33.0