From patchwork Mon Jan 25 18:39:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 371400 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, 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 C6541C433E9 for ; Tue, 26 Jan 2021 04:48:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89E6D22B2C for ; Tue, 26 Jan 2021 04:48:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726166AbhAZEsg (ORCPT ); Mon, 25 Jan 2021 23:48:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:33594 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729998AbhAYSpn (ORCPT ); Mon, 25 Jan 2021 13:45:43 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 97C942083E; Mon, 25 Jan 2021 18:45:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611600302; bh=Htx6PgQPWCpEABjyXQR66WLslRWX+D+EPaJOlMYiHTc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bJJb8xKFhYEM8cb3MmVT4OjMF+nFnC4gQKdHiivqqA+3bLPGXh9b/QOsn4oLCn0J9 SfgFzRdbibWVwKms/cc3jeCw+XkhtVb80wt68MLCmKXxwT4I36wMXbJf++QV+9aKoH CS3e/+n7+sLecAzdOx2SRbdGHli6cZQWqUXEurZQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vincent Mailhol , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 5.4 50/86] can: vxcan: vxcan_xmit: fix use after free bug Date: Mon, 25 Jan 2021 19:39:32 +0100 Message-Id: <20210125183203.169714464@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210125183201.024962206@linuxfoundation.org> References: <20210125183201.024962206@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vincent Mailhol [ Upstream commit 75854cad5d80976f6ea0f0431f8cedd3bcc475cb ] 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 Signed-off-by: Sasha Levin --- 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 d6ba9426be4de..b1baa4ac1d537 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: