From patchwork Tue Apr 13 12:41:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 420686 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=-15.7 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, 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 E7AA4C433ED for ; Tue, 13 Apr 2021 12:41:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9A07613B2 for ; Tue, 13 Apr 2021 12:41:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231455AbhDMMmB (ORCPT ); Tue, 13 Apr 2021 08:42:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230449AbhDMMl7 (ORCPT ); Tue, 13 Apr 2021 08:41:59 -0400 Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02EFEC061574 for ; Tue, 13 Apr 2021 05:41:40 -0700 (PDT) Received: by mail-pf1-x42f.google.com with SMTP id m11so11344259pfc.11 for ; Tue, 13 Apr 2021 05:41:39 -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:mime-version :content-transfer-encoding; bh=opUzB3eTmDP6Bt69/GX/ex4UqF+MDRj/bhyGWT7WwcU=; b=ITAAbhFu3kgJyyVKsyNLRNMNOhBy3Xw19QEDaq2csA/jYDv528rCEyOICaL4BgZSAY WEzp7GJkHNg967ik9Y1P3aUglUPQCTa7g/UOHD5jYzT5C501ZMSDujZiMhfZ9bgIUpYj qUPWbTVF6uVk6vmN3dfXPYXmj9573IUqUfpvLI3+x08q2K9Bh7roPF6WAeEVdFE52YJr 1qFmZbwP6ZQ+YYi1BfH+JNSi3YxNspm7wg84K+rJuNboCGRvqQCIKYDbp/cmiGGBa5hu Cb+e2oKN7BoFySgJzHM1VqNhWe6EkjguKntgF7Rgc+Muqz/r5zBvYfYXNs3eJvaX0f15 BcUw== 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:mime-version :content-transfer-encoding; bh=opUzB3eTmDP6Bt69/GX/ex4UqF+MDRj/bhyGWT7WwcU=; b=Y8E7LUde2I2hQJCMddoSn9CZDkNNBWqLHoPRGm7lTj+uvTacyRg2OXkax7KSMg7+sv 1k65jyWn9eG0SQrZXoHMofUvDH5kie4H5A1uE5BqfqG1VYct7hSzGYAROMvf+Bieflh/ jAdOo+6t928Z6U+M9p6z79YKjEcQuMYhY2cA9T6WGjoBzxZuafTpidQsy/SNAE6ZV9Is Kzp14A91z8WhwXX1/9aWAfs3RejKgppKH9Pw2kJOSX22ycQYcXpFkAfehAO76fMu/9o/ INUgiQBe6ZaJobJA7GcyVlkiihZkp0BaKOXbStywoTPU6NY9A814A97T6cQ8EZCxtbYb c3hw== X-Gm-Message-State: AOAM531uljJ+bhPDpqq3SuPfD6V7JPNNKS18OHaBf+m4riPQ2SCzOTD8 ZYXETc/dKZ48fiFSyaHOOxFfhoB0Tas= X-Google-Smtp-Source: ABdhPJzZnC+97YvscCF3NJVKA1wVe6WlFDI8srf3t9P6ULxQXnbgtkMpgHO2RuiNHRw0EVNISLeHBg== X-Received: by 2002:a65:4046:: with SMTP id h6mr31417369pgp.345.1618317699630; Tue, 13 Apr 2021 05:41:39 -0700 (PDT) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:485b:46b2:8be1:2cdd]) by smtp.gmail.com with ESMTPSA id a25sm7988108pfo.27.2021.04.13.05.41.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Apr 2021 05:41:39 -0700 (PDT) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski Cc: netdev , Eric Dumazet , Eric Dumazet , Guenter Roeck , Xuan Zhuo , "Michael S. Tsirkin" , Jason Wang Subject: [PATCH net] gro: ensure frag0 meets IP header alignment Date: Tue, 13 Apr 2021 05:41:35 -0700 Message-Id: <20210413124136.2750358-1-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet After commit 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head") Guenter Roeck reported one failure in his tests using sh architecture. After much debugging, we have been able to spot silent unaligned accesses in inet_gro_receive() The issue at hand is that upper networking stacks assume their header is word-aligned. Low level drivers are supposed to reserve NET_IP_ALIGN bytes before the Ethernet header to make that happen. This patch hardens skb_gro_reset_offset() to not allow frag0 fast-path if the fragment is not properly aligned. Some arches like x86, arm64 and powerpc do not care and define NET_IP_ALIGN as 0, this extra check will be a NOP for them. Note that if frag0 is not used, GRO will call pskb_may_pull() as many times as needed to pull network and transport headers. Fixes: 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head") Fixes: 78a478d0efd9 ("gro: Inline skb_gro_header and cache frag0 virtual address") Signed-off-by: Eric Dumazet Reported-by: Guenter Roeck Cc: Xuan Zhuo Cc: "Michael S. Tsirkin" Cc: Jason Wang Acked-by: Michael S. Tsirkin --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index af8c1ea040b9364b076e2d72f04dc3de2d7e2f11..1f79b9aa9a3f2392fddd1401f95ad098b5e03204 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5924,7 +5924,8 @@ static void skb_gro_reset_offset(struct sk_buff *skb) NAPI_GRO_CB(skb)->frag0_len = 0; if (!skb_headlen(skb) && pinfo->nr_frags && - !PageHighMem(skb_frag_page(frag0))) { + !PageHighMem(skb_frag_page(frag0)) && + (!NET_IP_ALIGN || !(skb_frag_off(frag0) & 3))) { NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, skb_frag_size(frag0),