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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D4C9C433F5 for ; Mon, 18 Apr 2022 14:14:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343968AbiDRORY (ORCPT ); Mon, 18 Apr 2022 10:17:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343981AbiDROQm (ORCPT ); Mon, 18 Apr 2022 10:16:42 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 991FA396AC; Mon, 18 Apr 2022 06:13:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0C36160F62; Mon, 18 Apr 2022 13:12:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D75BBC385A7; Mon, 18 Apr 2022 13:12:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650287571; bh=5JfMoSWtEgqwT724tW5dh1g5BN/nqvQiRbu8mOUvsyk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LBdKyRnT38UVtmilg1fA8KLm4OZQpeK5kzNRAXRkxAWp49YytR8owcNuLZFYKXRcL bgSPVLNMZwK/55K+WB2EuVGpSEi0A4BWcmBt3AbnqenYo5ku5Zz3f9ZOiE3H06sOuH iWRCC53IeVKNTtM1i3rlwdSxqFlhxW0HwM63hnpo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guillaume Nault , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 202/218] veth: Ensure eth header is in skbs linear part Date: Mon, 18 Apr 2022 14:14:28 +0200 Message-Id: <20220418121207.570876742@linuxfoundation.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220418121158.636999985@linuxfoundation.org> References: <20220418121158.636999985@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Guillaume Nault [ Upstream commit 726e2c5929de841fdcef4e2bf995680688ae1b87 ] After feeding a decapsulated packet to a veth device with act_mirred, skb_headlen() may be 0. But veth_xmit() calls __dev_forward_skb(), which expects at least ETH_HLEN byte of linear data (as __dev_forward_skb2() calls eth_type_trans(), which pulls ETH_HLEN bytes unconditionally). Use pskb_may_pull() to ensure veth_xmit() respects this constraint. kernel BUG at include/linux/skbuff.h:2328! RIP: 0010:eth_type_trans+0xcf/0x140 Call Trace: __dev_forward_skb2+0xe3/0x160 veth_xmit+0x6e/0x250 [veth] dev_hard_start_xmit+0xc7/0x200 __dev_queue_xmit+0x47f/0x520 ? skb_ensure_writable+0x85/0xa0 ? skb_mpls_pop+0x98/0x1c0 tcf_mirred_act+0x442/0x47e [act_mirred] tcf_action_exec+0x86/0x140 fl_classify+0x1d8/0x1e0 [cls_flower] ? dma_pte_clear_level+0x129/0x1a0 ? dma_pte_clear_level+0x129/0x1a0 ? prb_fill_curr_block+0x2f/0xc0 ? skb_copy_bits+0x11a/0x220 __tcf_classify+0x58/0x110 tcf_classify_ingress+0x6b/0x140 __netif_receive_skb_core.constprop.0+0x47d/0xfd0 ? __iommu_dma_unmap_swiotlb+0x44/0x90 __netif_receive_skb_one_core+0x3d/0xa0 netif_receive_skb+0x116/0x170 be_process_rx+0x22f/0x330 [be2net] be_poll+0x13c/0x370 [be2net] __napi_poll+0x2a/0x170 net_rx_action+0x22f/0x2f0 __do_softirq+0xca/0x2a8 __irq_exit_rcu+0xc1/0xe0 common_interrupt+0x83/0xa0 Fixes: e314dbdc1c0d ("[NET]: Virtual ethernet device driver.") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/veth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index ee7460ee3d05..57ff2fd95f75 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -114,7 +114,7 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev) rcu_read_lock(); rcv = rcu_dereference(priv->peer); - if (unlikely(!rcv)) { + if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) { kfree_skb(skb); goto drop; } -- 2.35.1