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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 CDEBFC433E7 for ; Sun, 18 Oct 2020 19:39:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2184207DE for ; Sun, 18 Oct 2020 19:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603049955; bh=kL3mHtvkjdVI/1qd0rJa0p8tK+xfTgXhxpSVFK5HJho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nfZ0q7jJOyxaMTQ7b6oycobQ+JugK8gI+xpR0AsZkxYsCAa2tzbGgBEFqOZqPiHvL P5HyZA3/UWEjDrbuRFOpZfGxPu5QWvcL+APVaEw+DtBsF275lbXFwHW/LzNbIsefl5 SL5lGYqJYkRY858Yq/DoXo+iRjd9UVJdqwsVxVq8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731047AbgJRTYv (ORCPT ); Sun, 18 Oct 2020 15:24:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:38946 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730911AbgJRTYr (ORCPT ); Sun, 18 Oct 2020 15:24:47 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1C8D6222EB; Sun, 18 Oct 2020 19:24:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603049087; bh=kL3mHtvkjdVI/1qd0rJa0p8tK+xfTgXhxpSVFK5HJho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WkaU2M4FqawdP5U98QtRBmlDOWkdhUkJI1Q1VDJU1i8hIoygnvp7TKwn+JlvRPujR 0pvC1ZkoxxNrQOR3u7i62XVAngr1hyqnULQTbqDtI4zZhQpJ4oKq4E0X3SWPMZkSzu rgeO6ufqmAhyWwxlTEkuJg94TRUhRemII57FnxLA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Cong Wang , syzbot+4a2c52677a8a1aa283cb@syzkaller.appspotmail.com, William Tu , Willem de Bruijn , Xie He , Jakub Kicinski , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 23/56] ip_gre: set dev->hard_header_len and dev->needed_headroom properly Date: Sun, 18 Oct 2020 15:23:44 -0400 Message-Id: <20201018192417.4055228-23-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201018192417.4055228-1-sashal@kernel.org> References: <20201018192417.4055228-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Cong Wang [ Upstream commit fdafed459998e2be0e877e6189b24cb7a0183224 ] GRE tunnel has its own header_ops, ipgre_header_ops, and sets it conditionally. When it is set, it assumes the outer IP header is already created before ipgre_xmit(). This is not true when we send packets through a raw packet socket, where L2 headers are supposed to be constructed by user. Packet socket calls dev_validate_header() to validate the header. But GRE tunnel does not set dev->hard_header_len, so that check can be simply bypassed, therefore uninit memory could be passed down to ipgre_xmit(). Similar for dev->needed_headroom. dev->hard_header_len is supposed to be the length of the header created by dev->header_ops->create(), so it should be used whenever header_ops is set, and dev->needed_headroom should be used when it is not set. Reported-and-tested-by: syzbot+4a2c52677a8a1aa283cb@syzkaller.appspotmail.com Cc: William Tu Acked-by: Willem de Bruijn Signed-off-by: Cong Wang Acked-by: Xie He Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/ip_gre.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index ffcb5983107db..de6f89511a216 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -680,9 +680,7 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb, } if (dev->header_ops) { - /* Need space for new headers */ - if (skb_cow_head(skb, dev->needed_headroom - - (tunnel->hlen + sizeof(struct iphdr)))) + if (skb_cow_head(skb, 0)) goto free_skb; tnl_params = (const struct iphdr *)skb->data; @@ -800,7 +798,11 @@ static void ipgre_link_update(struct net_device *dev, bool set_mtu) len = tunnel->tun_hlen - len; tunnel->hlen = tunnel->hlen + len; - dev->needed_headroom = dev->needed_headroom + len; + if (dev->header_ops) + dev->hard_header_len += len; + else + dev->needed_headroom += len; + if (set_mtu) dev->mtu = max_t(int, dev->mtu - len, 68); @@ -1003,6 +1005,7 @@ static void __gre_tunnel_init(struct net_device *dev) tunnel->parms.iph.protocol = IPPROTO_GRE; tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen; + dev->needed_headroom = tunnel->hlen + sizeof(tunnel->parms.iph); dev->features |= GRE_FEATURES; dev->hw_features |= GRE_FEATURES; @@ -1046,10 +1049,14 @@ static int ipgre_tunnel_init(struct net_device *dev) return -EINVAL; dev->flags = IFF_BROADCAST; dev->header_ops = &ipgre_header_ops; + dev->hard_header_len = tunnel->hlen + sizeof(*iph); + dev->needed_headroom = 0; } #endif } else if (!tunnel->collect_md) { dev->header_ops = &ipgre_header_ops; + dev->hard_header_len = tunnel->hlen + sizeof(*iph); + dev->needed_headroom = 0; } return ip_tunnel_init(dev); -- 2.25.1