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=-16.8 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,USER_AGENT_GIT autolearn=ham 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 34078C43381 for ; Wed, 20 Jan 2021 13:58:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2C0D233A2 for ; Wed, 20 Jan 2021 13:58:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731352AbhATNzr (ORCPT ); Wed, 20 Jan 2021 08:55:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732707AbhATMwt (ORCPT ); Wed, 20 Jan 2021 07:52:49 -0500 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 11FA1C0613D3 for ; Wed, 20 Jan 2021 04:52:09 -0800 (PST) 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 1l2Cxz-00054y-LV for linux-can@vger.kernel.org; Wed, 20 Jan 2021 13:52:07 +0100 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id 2BF845C8B0F for ; Wed, 20 Jan 2021 12:52:05 +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 0D0445C8AFD; Wed, 20 Jan 2021 12:52:04 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id 2415bd1e; Wed, 20 Jan 2021 12:52:03 +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, Vincent Mailhol , Marc Kleine-Budde Subject: [net 1/3] can: dev: can_restart: fix use after free bug Date: Wed, 20 Jan 2021 13:52:00 +0100 Message-Id: <20210120125202.2187358-2-mkl@pengutronix.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210120125202.2187358-1-mkl@pengutronix.de> References: <20210120125202.2187358-1-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: linux-can@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org From: Vincent Mailhol After calling netif_rx_ni(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is accessed after the netif_rx_ni() in: stats->rx_bytes += cf->len; Reordering the lines solves the issue. Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface") Link: https://lore.kernel.org/r/20210120114137.200019-2-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index 3486704c8a95..8b1ae023cb21 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -592,11 +592,11 @@ static void can_restart(struct net_device *dev) cf->can_id |= CAN_ERR_RESTARTED; - netif_rx_ni(skb); - stats->rx_packets++; stats->rx_bytes += cf->len; + netif_rx_ni(skb); + restart: netdev_dbg(dev, "restarted\n"); priv->can_stats.restarts++; base-commit: 9c30ae8398b0813e237bde387d67a7f74ab2db2d -- 2.29.2