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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 15957C74A4B for ; Thu, 11 Jul 2019 10:18:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7541208E4 for ; Thu, 11 Jul 2019 10:18:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OlVNs1c7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728354AbfGKKSv (ORCPT ); Thu, 11 Jul 2019 06:18:51 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:39232 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727680AbfGKKSu (ORCPT ); Thu, 11 Jul 2019 06:18:50 -0400 Received: by mail-wm1-f68.google.com with SMTP id z23so926687wma.4 for ; Thu, 11 Jul 2019 03:18:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=M/uZee31+cHAFk1gSq+aHFn4EaVxUbqEZxjMETaQntY=; b=OlVNs1c7TlGSNJnlZa4d3dZeomiSGBKLz60z+mWL1qIHko4o1Qzd+4wQnYdtLMb2UJ 0URhYVfBPJpZyPbRzZD/j1Vbo3hFbvb3aqj0mKo7xKGgjfOXXELK5PWRzhcLBJ4QgjxT zwxMmWGovIjV/89WEUK0NOKY7GDuD/t9+bER/0Jny98WTVpphJ6gLBJSqUsdw2nadsgB Vz5Q1IYLDCL2jUWt0rwaKtNOattkiOJ+StE2w4b7mZDcK+nYJqbxAuop6CYUr2btU3lz jVzHTyJGyy33FEsmfDdpVBsLxFqHHC3YpGERvZympZoDP21y4YhDxFQWPWJI9vOjKanI po0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=M/uZee31+cHAFk1gSq+aHFn4EaVxUbqEZxjMETaQntY=; b=MISYvftxd7tqO1zhsKuZDvmzZ2cYKxT6nTg1xgTYb1ImW/BaMSskiZlfk75XjFBP+v Y/dcC7BB2SpZuafok5ErMJpea9sTcg74i0SfnRUnAPmmFfs2KE/GfJhKUud0Jowo5FCc tLFxkZQSDah5MH9jxXY4vwDIppbDiw37rf9dp/Qy81IgGw8hDCD28DEM3q1mPfobmSIX 25PPQZrsZCP6sQAF/peABsArRKq6J00S2T0hCVZTHAQWDVGL4lqh+2lDNe2H9RgaC0u4 6H8KKqM55iURZvwKjeobPBtsEpy4jHciIBLyHtFdxywYLKkpvDT+YgACS3YcoAQA3v8u sf8g== X-Gm-Message-State: APjAAAWgC8x347M3ls+CBjAJbbdPpWyh755IqRS1ZbvsYQkr8IO3m6Pp juEuI0FX2bxohTnVg6u5ikk= X-Google-Smtp-Source: APXvYqw+owaCYNESZBznl8Qv0W52VQIFOaN4rJkDoMbtN4+Ofxw81s8GAPw3j4ge2siMCe0flQizJw== X-Received: by 2002:a7b:cf32:: with SMTP id m18mr3519735wmg.27.1562840328610; Thu, 11 Jul 2019 03:18:48 -0700 (PDT) Received: from [192.168.8.147] (143.160.185.81.rev.sfr.net. [81.185.160.143]) by smtp.gmail.com with ESMTPSA id v15sm5252455wrt.25.2019.07.11.03.18.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Jul 2019 03:18:47 -0700 (PDT) Subject: Re: [PATCH net 2/4] tcp: tcp_fragment() should apply sane memory limits To: Christoph Paasch , Eric Dumazet Cc: "Prout, Andrew - LLSC - MITLL" , David Miller , netdev , Greg Kroah-Hartman , Jonathan Looney , Neal Cardwell , Tyler Hicks , Yuchung Cheng , Bruce Curtis , Jonathan Lemon , Dustin Marquess References: <20190617170354.37770-1-edumazet@google.com> <20190617170354.37770-3-edumazet@google.com> <03cbcfdf-58a4-dbca-45b1-8b17f229fa1d@gmail.com> <63cd99ed3d0c440185ebec3ad12327fc@ll.mit.edu> <96791fd5-8d36-2e00-3fef-60b23bea05e5@gmail.com> From: Eric Dumazet Message-ID: Date: Thu, 11 Jul 2019 12:18:46 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 7/11/19 9:28 AM, Christoph Paasch wrote: > > Would it make sense to always allow the alloc in tcp_fragment when coming from __tcp_retransmit_skb() through the retransmit-timer ? > > AFAICS, the crasher was when an attacker sends "fake" SACK-blocks. Thus, we would still be protected from too much fragmentation, but at least would always allow the retransmission to go out. > > I guess this could be done and hopefully something that can be backported without too much pain, but I am sure some people will complain because reverting to timeouts might still show regressions :/