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=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 5F0E7C433DB for ; Wed, 20 Jan 2021 20:50:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12F1323602 for ; Wed, 20 Jan 2021 20:50:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729197AbhATNzg (ORCPT ); Wed, 20 Jan 2021 08:55:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732751AbhATMwt (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 3CDAEC06179A 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-000551-RZ 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 3789F5C8B11 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 2C3315C8AFF; Wed, 20 Jan 2021 12:52:04 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id 0ba0132d; 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 2/3] can: vxcan: vxcan_xmit: fix use after free bug Date: Wed, 20 Jan 2021 13:52:01 +0100 Message-Id: <20210120125202.2187358-3-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 canfd_frame cfd which aliases skb memory is accessed after the netif_rx_ni(). Fixes: a8f820a380a2 ("can: add Virtual CAN Tunnel driver (vxcan)") Link: https://lore.kernel.org/r/20210120114137.200019-3-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde --- drivers/net/can/vxcan.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c index fa47bab510bb..f9a524c5f6d6 100644 --- a/drivers/net/can/vxcan.c +++ b/drivers/net/can/vxcan.c @@ -39,6 +39,7 @@ static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev) struct net_device *peer; struct canfd_frame *cfd = (struct canfd_frame *)skb->data; struct net_device_stats *peerstats, *srcstats = &dev->stats; + u8 len; if (can_dropped_invalid_skb(dev, skb)) return NETDEV_TX_OK; @@ -61,12 +62,13 @@ static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev) skb->dev = peer; skb->ip_summed = CHECKSUM_UNNECESSARY; + len = cfd->len; if (netif_rx_ni(skb) == NET_RX_SUCCESS) { srcstats->tx_packets++; - srcstats->tx_bytes += cfd->len; + srcstats->tx_bytes += len; peerstats = &peer->stats; peerstats->rx_packets++; - peerstats->rx_bytes += cfd->len; + peerstats->rx_bytes += len; } out_unlock: -- 2.29.2