From patchwork Thu Jun 17 00:09:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Maciej_=C5=BBenczykowski?= X-Patchwork-Id: 461853 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 75E42C49EA3 for ; Thu, 17 Jun 2021 00:10:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6140861359 for ; Thu, 17 Jun 2021 00:10:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234942AbhFQAM0 (ORCPT ); Wed, 16 Jun 2021 20:12:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234905AbhFQAMT (ORCPT ); Wed, 16 Jun 2021 20:12:19 -0400 Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30FF7C06175F; Wed, 16 Jun 2021 17:10:11 -0700 (PDT) Received: by mail-pl1-x635.google.com with SMTP id e7so1990278plj.7; Wed, 16 Jun 2021 17:10:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=2EVe6yWId4rmhH7SxvVNrCWJZunis2SdOr3XkJ2G69A=; b=foX74GqvdnCt/QsbrX2s6sJE/O6n8eGQ/zCW0eXZX4e2RmlMHmPXbWU//EXUnt9MbI U3jqGNyGv7bj7AdqK6jS78S5KfOI3GkGPLK1FikXKnDlq5an/s4bZgKPnMpo2c7YBnE3 4scItAkG/6WKsbOUPb5XwceEOgilSIQQfHpMCj5DQHjn8afEeEe/Ick8m9rSPNJ7aaRZ YpQ9CGyhpife+LqMCZtqd7XhXM57MhxpJDm3ekD4oBkSuGgvejvX8kDw6Zl77SSDQ8FA zOq6mIXhTCbaqY9DSANRycRRPJBKY6R0RnpoHpgJhnlCqChZfLCaw78DbTykio0+2sH1 un0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=2EVe6yWId4rmhH7SxvVNrCWJZunis2SdOr3XkJ2G69A=; b=U+A5JxrhNrwtL/RNuQYlJdabkSLwHDbE9goZnRx/cMn9vLPqAUMp/GNGDwuITXnN96 zmQTnR7DkttKXIFW5gIxoPiNFDF2tfDShKc2ykVpnRC+aS7QMdVQQCW4ik+FHIWdztd4 0NK9awRt0BaIoAqeP24AH6FfhdDD8LJWe2HdI/9Dd+XI0f7Nyp1Oqx7Qr1N+/ODjMC1W 4KEko/P0Sx9XUAH8GjLGSFD32K5vyDQO7yJquC2SENXPLirKJ2OE6oc9HGVs9l+/tLg/ IVDpx7YjML19TxLbCH5KJuIGdnp+j+jSBY1Ivcq9FE2yvUoyFOYqY96zRjPlDzbL0LYC HUUw== X-Gm-Message-State: AOAM530QrOPahmEPm7cVcZM8ktBnmFQ0xBSYB/UMxG/LjDn9wQqYaR8y js8T44OA0+Nt0KLY8I6fwdU= X-Google-Smtp-Source: ABdhPJwtMFezZ2ja2Z+GrWh+C8/6DGBa3R1dsFmSpZ02TVPG5lzSFdH5/ESoJ/7klenA0M0gpEgf+A== X-Received: by 2002:a17:90b:3004:: with SMTP id hg4mr13712647pjb.12.1623888610716; Wed, 16 Jun 2021 17:10:10 -0700 (PDT) Received: from athina.mtv.corp.google.com ([2620:15c:211:200:926a:e8dd:9095:3ddd]) by smtp.gmail.com with ESMTPSA id r92sm6599633pja.6.2021.06.16.17.10.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jun 2021 17:10:10 -0700 (PDT) From: =?utf-8?q?Maciej_=C5=BBenczykowski?= To: =?utf-8?q?Maciej_=C5=BBenczykowski?= , Alexei Starovoitov , Daniel Borkmann Cc: Linux Network Development Mailing List , Linux Kernel Mailing List , BPF Mailing List , "David S . Miller" , Willem de Bruijn Subject: [PATCH bpf-next v2 4/4] bpf: more lenient bpf_skb_net_shrink() with BPF_F_ADJ_ROOM_FIXED_GSO Date: Wed, 16 Jun 2021 17:09:53 -0700 Message-Id: <20210617000953.2787453-4-zenczykowski@gmail.com> X-Mailer: git-send-email 2.32.0.272.g935e593368-goog In-Reply-To: <20210617000953.2787453-1-zenczykowski@gmail.com> References: <20210617000953.2787453-1-zenczykowski@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Maciej Żenczykowski This is to more closely match behaviour of bpf_skb_change_proto() which now does not adjust gso_size, and thus thoretically supports all gso types, and does not need to set SKB_GSO_DODGY nor reset gso_segs to zero. Something similar should probably be done with bpf_skb_net_grow(), but that code scares me. Cc: Daniel Borkmann Cc: Willem de Bruijn Signed-off-by: Maciej Żenczykowski --- net/core/filter.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 8f05498f497e..faf2bae0309b 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3506,11 +3506,10 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, BPF_F_ADJ_ROOM_NO_CSUM_RESET))) return -EINVAL; - if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) { - /* udp gso_size delineates datagrams, only allow if fixed */ - if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) || - !(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) - return -ENOTSUPP; + if (skb_is_gso(skb) && + !skb_is_gso_tcp(skb) && + !(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) { + return -ENOTSUPP; } ret = skb_unclone(skb, GFP_ATOMIC); @@ -3521,12 +3520,11 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, if (unlikely(ret < 0)) return ret; - if (skb_is_gso(skb)) { + if (skb_is_gso(skb) && !(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) { struct skb_shared_info *shinfo = skb_shinfo(skb); /* Due to header shrink, MSS can be upgraded. */ - if (!(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) - skb_increase_gso_size(shinfo, len_diff); + skb_increase_gso_size(shinfo, len_diff); /* Header must be checked, and gso_segs recomputed. */ shinfo->gso_type |= SKB_GSO_DODGY;