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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 F0360C38A2A for ; Fri, 8 May 2020 13:04:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D284C208E4 for ; Fri, 8 May 2020 13:04:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588943082; bh=63mWrDenOfyWtIaxJqhgasiakcPCm97DHNs3RjYaL8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eTiFe00Jy7a9CRt5yQJRoUvmA4h3sZxaf6W+kdwIkg+27QiaaB9JacAw08wYoye5T Rz/0+WAi0z9dTI0/e47FkoVPfPsRZixoBrjb9gC6wyE+sYOsUm/Xa/zbXLH/D0gcW3 W1ehwLqyiWCBJSPTGsmGvkQh0C3NcUV6s8oNjIK4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729885AbgEHNEm (ORCPT ); Fri, 8 May 2020 09:04:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:53542 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729705AbgEHMsx (ORCPT ); Fri, 8 May 2020 08:48:53 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98C0F206D6; Fri, 8 May 2020 12:48:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588942133; bh=63mWrDenOfyWtIaxJqhgasiakcPCm97DHNs3RjYaL8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2tThTPVjjIRxmgCfIjZzAOPVnT4Wu3tL5OfIpQ8Lmr4F8+Y/ZX/eR9J8dyPsa4vWD R1EQ6d8HqNVoAgkCVO+Jt9gBJTxudCoGJ+31LFHaXxDn5WgatgrrpUKjt4IHP2JQEZ pLHe8PYxQO6gLyv5tU18Oz3nFPk+KlquY3uWjTsY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Herbert Xu , "David S. Miller" Subject: [PATCH 4.4 309/312] macvlan: Fix potential use-after free for broadcasts Date: Fri, 8 May 2020 14:35:00 +0200 Message-Id: <20200508123146.249842508@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508123124.574959822@linuxfoundation.org> References: <20200508123124.574959822@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Herbert Xu commit 260916dfb48c374f7840f3b86e69afd3afdb6e96 upstream. When we postpone a broadcast packet we save the source port in the skb if it is local. However, the source port can disappear before we get a chance to process the packet. This patch fixes this by holding a ref count on the netdev. It also delays the skb->cb modification until after we allocate the new skb as you should not modify shared skbs. Fixes: 412ca1550cbe ("macvlan: Move broadcasts into a work queue") Signed-off-by: Herbert Xu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/macvlan.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -305,6 +305,8 @@ static void macvlan_process_broadcast(st rcu_read_unlock(); + if (src) + dev_put(src->dev); kfree_skb(skb); cond_resched(); @@ -312,6 +314,7 @@ static void macvlan_process_broadcast(st } static void macvlan_broadcast_enqueue(struct macvlan_port *port, + const struct macvlan_dev *src, struct sk_buff *skb) { struct sk_buff *nskb; @@ -321,8 +324,12 @@ static void macvlan_broadcast_enqueue(st if (!nskb) goto err; + MACVLAN_SKB_CB(nskb)->src = src; + spin_lock(&port->bc_queue.lock); if (skb_queue_len(&port->bc_queue) < MACVLAN_BC_QUEUE_LEN) { + if (src) + dev_hold(src->dev); __skb_queue_tail(&port->bc_queue, nskb); err = 0; } @@ -432,8 +439,7 @@ static rx_handler_result_t macvlan_handl goto out; } - MACVLAN_SKB_CB(skb)->src = src; - macvlan_broadcast_enqueue(port, skb); + macvlan_broadcast_enqueue(port, src, skb); return RX_HANDLER_PASS; }