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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 26ABAC433E6 for ; Tue, 1 Sep 2020 16:53:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1DD621582 for ; Tue, 1 Sep 2020 16:53:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598979197; bh=q/sPydxvvwDDp2lL6x2VJGwVP6sjOCOiyjHZ35pvM74=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JEdjHhLyPYCyFF8Fq9szfaxs9vNxaF1pF8NkHdexJ6Rjzak9BYcQ6Zsj9PmY5qZLf lK0w3dW0YoxyiXj2GFtACmUo/gByAPYM38t1oSWdPuN9q6rysDMj1h3CSfS8PHeDU8 jwrX3VqCfYHHBhqNdzAGNbSuts1Vq6E80TehoL58= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730021AbgIAPZR (ORCPT ); Tue, 1 Sep 2020 11:25:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:43962 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728767AbgIAPWX (ORCPT ); Tue, 1 Sep 2020 11:22:23 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 9865F2100A; Tue, 1 Sep 2020 15:22:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598973743; bh=q/sPydxvvwDDp2lL6x2VJGwVP6sjOCOiyjHZ35pvM74=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q596aAFE+zOZdEG7rSWjsFkzLnWdfZuZFs968/LS54pw78o3h/bq1JURC/8/ui0PA Cdt/zJGR0cEtW2chWkVpDCgks8cK9BBODxsEAeL6c5eNGsA29L53pCIVWQjFmWBbRy bKipkwABG5+3vyKaUHtX+nBq4/QvSGgI8rw7Y6bA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miaohe Lin , "David S. Miller" Subject: [PATCH 4.19 003/125] net: Fix potential wrong skb->protocol in skb_vlan_untag() Date: Tue, 1 Sep 2020 17:09:18 +0200 Message-Id: <20200901150934.750782202@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901150934.576210879@linuxfoundation.org> References: <20200901150934.576210879@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: Miaohe Lin [ Upstream commit 55eff0eb7460c3d50716ed9eccf22257b046ca92 ] We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). So we should pull VLAN_HLEN + sizeof(unsigned short) in skb_vlan_untag() or we may access the wrong data. Fixes: 0d5501c1c828 ("net: Always untag vlan-tagged traffic on input.") Signed-off-by: Miaohe Lin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/skbuff.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5128,8 +5128,8 @@ struct sk_buff *skb_vlan_untag(struct sk skb = skb_share_check(skb, GFP_ATOMIC); if (unlikely(!skb)) goto err_free; - - if (unlikely(!pskb_may_pull(skb, VLAN_HLEN))) + /* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */ + if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short)))) goto err_free; vhdr = (struct vlan_hdr *)skb->data;