From patchwork Tue Jun 9 17:45:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 224640 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, 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 3C221C433DF for ; Tue, 9 Jun 2020 18:04:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1434820801 for ; Tue, 9 Jun 2020 18:04:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591725898; bh=R/2+iH0ntOAXXcyfdHjyJIeGtR8m6nlM7VYdO+xk6Gs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sfAVh/gDS/d0V6NRNAnRwmztyNQ1ZZwfUUfqHfsg8drNJw8BZNAegH2dqIjheqrPP USjZS9s1VRht6BNoxcTkuoqpXrjtGZ9Kvxz5k45/lmWhP9pqiJiXnnhmK7Y/goi0ez XD22Qv9OTvgTMzNZqcJN5JPy8qaN6y28nG5yRJoY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388002AbgFISEi (ORCPT ); Tue, 9 Jun 2020 14:04:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:42154 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728537AbgFIRwH (ORCPT ); Tue, 9 Jun 2020 13:52:07 -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 BFC2F20774; Tue, 9 Jun 2020 17:52:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591725127; bh=R/2+iH0ntOAXXcyfdHjyJIeGtR8m6nlM7VYdO+xk6Gs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PGiGlpsv78ZxLpPpISRRRINaRgbklQyt0rsqe95S2IP7okbQM8MxyUL1R3CjOwz2e lRhTNvoXdgy8jPct9v1OyDjNvgPm9mK0au1OZ8wJ7ViMA5D6p0aJSqASnfweWcZiNP TcxUFZlzTWAdjvJoMkDtcPxhOeKzBFiGCECDu4PI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Willem de Bruijn , "David S. Miller" Subject: [PATCH 5.4 11/34] net: be more gentle about silly gso requests coming from user Date: Tue, 9 Jun 2020 19:45:07 +0200 Message-Id: <20200609174054.051190910@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200609174052.628006868@linuxfoundation.org> References: <20200609174052.628006868@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit 7c6d2ecbda83150b2036a2b36b21381ad4667762 ] Recent change in virtio_net_hdr_to_skb() broke some packetdrill tests. When --mss=XXX option is set, packetdrill always provide gso_type & gso_size for its inbound packets, regardless of packet size. if (packet->tcp && packet->mss) { if (packet->ipv4) gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; gso.gso_size = packet->mss; } Since many other programs could do the same, relax virtio_net_hdr_to_skb() to no longer return an error, but instead ignore gso settings. This keeps Willem intent to make sure no malicious packet could reach gso stack. Note that TCP stack has a special logic in tcp_set_skb_tso_segs() to clear gso_size for small packets. Fixes: 6dd912f82680 ("net: check untrusted gso_size at kernel entry") Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Acked-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/virtio_net.h | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -109,16 +109,17 @@ retry: if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size); + struct skb_shared_info *shinfo = skb_shinfo(skb); - if (skb->len - p_off <= gso_size) - return -EINVAL; + /* Too small packets are not really GSO ones. */ + if (skb->len - p_off > gso_size) { + shinfo->gso_size = gso_size; + shinfo->gso_type = gso_type; - skb_shinfo(skb)->gso_size = gso_size; - skb_shinfo(skb)->gso_type = gso_type; - - /* Header must be checked, and gso_segs computed. */ - skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; - skb_shinfo(skb)->gso_segs = 0; + /* Header must be checked, and gso_segs computed. */ + shinfo->gso_type |= SKB_GSO_DODGY; + shinfo->gso_segs = 0; + } } return 0;