From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A838D3B29E for ; Thu, 4 Apr 2019 17:40:11 -0400 (EDT) Received: by mail-pf1-x441.google.com with SMTP id c8so2018545pfd.10 for ; Thu, 04 Apr 2019 14:40:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LmzORkHaNY4xtWNzXV2yL0djjyADwevz4fZP3btn25k=; b=0u4MLXJfW6GYw5z+Q6+SdbhLoDQpHA/eOm8cvK1OGEdf484+04/UqOH8lvPT5McHOF sY3C9ECgvbsrL+RaHxIs3rfuxQFik53Suo9nsQFUXylhKyCIHvW4hZxmdO3x8myvZZ8c KWxLPdwYC83UPZC2kbQ9ojv/F/xmzkL98hk7GV1bB6OXL+5X2DvvmIdlJB8jmZcV4mWN ZFsNDjjuUoUGOXBVeObTxYEpKEq9iLuk1rZJxHYUMQ7kJEEr4XhuVS2TTTxc3XAknFlt vZpovPS34qkQTHkM8fSwlgkBy6xCkXMtgXRFYesFaL9ns1jpK+z4FWDAlkp+9YPRpCmj M4aw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LmzORkHaNY4xtWNzXV2yL0djjyADwevz4fZP3btn25k=; b=jgTm7EBHUo183d2DLjYiDkuEFEs5tZmRf8CLuti/4ft1oXDsy11D/OhQTskOLdbkH6 IEnqJRP/9P2pakHbc+oX+60FokJwoCbR2qpyfgwhjpXdC1tHDcQv7Cy7S2980cavEM92 bnVnNRkTglLbhKoG5/afPjdQMLBzITjzeFH1KQB45CIO0bb+S2gPKDFMoIz/pVC25Qd7 OFdDVPXwXiMm2doEb/lg4PUpIDPHhg6N2ioh9Y8BmzEX/vD7PnaqKNHRL5BqkE8PHNAd hjANorAbKX6eAs9M92AMV02ixKIfln3ljl7i32NSdkTN5/wXjF6bXMIzaFb1CcgpbjKd PEHg== X-Gm-Message-State: APjAAAWRaXEtjJ8Yc9QjxHZ7ZIS0If/BLhbsTe1J2ufjg81rUAl1jyy2 P6JoS4Q4OxIuEgIEPJ5EYjSLCg== X-Google-Smtp-Source: APXvYqzO8LHxNpPt/zpqJkjiJE7lGt0ELJrrAf9WSu6L5P8xa+1QvVueCezbNDOU2lplkJvX3gHa5g== X-Received: by 2002:a63:3f8d:: with SMTP id m135mr7840532pga.228.1554414010497; Thu, 04 Apr 2019 14:40:10 -0700 (PDT) Received: from shemminger-XPS-13-9360 ([167.220.102.127]) by smtp.gmail.com with ESMTPSA id d68sm11306202pfg.16.2019.04.04.14.40.10 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 04 Apr 2019 14:40:10 -0700 (PDT) Date: Thu, 4 Apr 2019 14:40:07 -0700 From: Stephen Hemminger To: Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= Cc: David Miller , netdev@vger.kernel.org, cake@lists.bufferbloat.net Message-ID: <20190404144007.7ac9bfe0@shemminger-XPS-13-9360> In-Reply-To: <87y34p1owe.fsf@toke.dk> References: <155438289359.18760.18027832614176337074.stgit@alrua-x1> <155438289374.18760.4278774647362746152.stgit@alrua-x1> <20190404123536.3c966937@shemminger-XPS-13-9360> <87y34p1owe.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] [PATCH net 2/2] sch_cake: Make sure we can write the IP header before changing DSCP bits X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Apr 2019 21:40:11 -0000 On Thu, 04 Apr 2019 22:44:33 +0200 Toke H=C3=B8iland-J=C3=B8rgensen wrote: > Stephen Hemminger writes: >=20 > > On Thu, 04 Apr 2019 15:01:33 +0200 > > Toke H=C3=B8iland-J=C3=B8rgensen wrote: > > =20 > >> static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash) > >> { > >> + int wlen =3D skb_network_offset(skb); =20 > > > > In theory this could be negative, you should handle that? > > Rather than calling may_pull() with a huge unsigned value. =20 >=20 > Huh, that would imply that skb->network_header points to before > skb->head; when does that happen? >=20 > Also, pskb_may_pull() does check for len > skb->len, so I guess a > follow-up question would be, "does it happen often enough to warrant > handling at this level"? >=20 > Also, I copied that bit from sch_dsmark, so if you really thing it needs > to be fixed, I guess we should fix both... >=20 > -Toke It should never happen just paranoid