From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yx1-f48.google.com (mail-yx1-f48.google.com [74.125.224.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A1B326ED3D for ; Sat, 16 May 2026 13:41:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.224.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778938871; cv=none; b=jSN+jBAtq+kDK0NwIRxMN8mxMKl0N1nqS9q9LKuIuahsDpsW+MXWK0PuoJrFKAgH01RhRIsgrYPTOfPux8PzbCoExxqiGdv38T6v8h5uJ+h/+wTN/lxnZcHAWpCPV0gMQeolx7l0mH6QeV5sGsC13jwZctGfBz70VgIhlxvRP+4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778938871; c=relaxed/simple; bh=WCt3b50bTtKkZzsevKEsc9yR17Tz2MFXOfcS5e01mXY=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: Mime-Version:Content-Type; b=kLdsHWG1/jQRJ1NUQnNrmwz0ahZ08lYL9wExI0ydh1DJBKTyrZsWbbQhln8Pxb32Qmy2/VloMytW6aRfG2kKJC0EF+04yOBaXdbtzCy2NraPG7Ct3q1kLkbk2Y2+Bu0kLwupoB2dmHoUvEkRNr2F/UEpSOpzbnLtqoE+xSsULFk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=IEMZFeD1; arc=none smtp.client-ip=74.125.224.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="IEMZFeD1" Received: by mail-yx1-f48.google.com with SMTP id 956f58d0204a3-65e39d1dd38so332080d50.3 for ; Sat, 16 May 2026 06:41:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778938869; x=1779543669; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=pEODD4rDv7CreJ46zyM98ddmC9t8jMACKmlZWxM6fIE=; b=IEMZFeD1rNY78/ei0gTrbrnIi52VkecjBvNC26g/9EecrAaTnmS0Bza0L4W8t2jCAl cQ3N+PcsIFWfS9S5IAAbdDfXAgWHNhVODCIkZWTrNUkBI246Zgj7hWRyXza6ND8obgYP sUIFdfHAekc6GORGW7b/t1f/OoTytfMAVszcalRyNEJ19xWlcJXZr8RJ0feWD92UvTdl sMyp1Tm9NK7/PIGqK3gx61NzyIhZ5uN/jFXK3CruIMgN/BFuQFIi+r/KI+AT32758J5m YOTfsHsdVjRc1nleVPMqqFnLZ8h9ycKXSEdMOB/VwI488qK7SOZiC7m7cS3Gf14fgsiA fAhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778938869; x=1779543669; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:x-gm-gg:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=pEODD4rDv7CreJ46zyM98ddmC9t8jMACKmlZWxM6fIE=; b=c2HW7qbIkxicgxSxtqa0dS4Hidjt0JViwQEL89HPiM0fga0TSQ7mQftRkLCLoGOiJu EKUPU+ysFUVmFoq243SSgzBV9RCpVKt/IfbbL7TfAorbalTtLMrl7IE/d4UbSoSfMElT e44HYQO4KSIKbsT+w5zBQVvGrWChyqVPSIvSz5GcHYeV4dOQC3rEil5kcz+x2LuXYrc3 cTbu5TTAh4zHOAIZq8IS0BBD9i9GVrMiyE1CrHjJZvHLorV3OHnwmHQ0iqFHDfpzC6gi 01RIq+32hlQtD7aafDMHomH1Bkl4q3cbfwTzh9Q4dZxgwwJ6L4WJx+XV0PYyIg3vyole Zh1g== X-Forwarded-Encrypted: i=1; AFNElJ+Mju4AZnZnKBDm274rtbbm8RiWZvHnkhVDtiPXYsNNvrI8BkjLQlcNNHhNdkBOgXoC1qC7e4M=@vger.kernel.org X-Gm-Message-State: AOJu0Ywy+VF8FF+fahGH4laJ/nGAAtxTvKmTJaDGR2vdWSPBBNTsjco0 WnYp/IS7vjOvMWbCnZsLfVwxgxVX3JET9Z9az8j1xGeoqKYf7vWxUnMs X-Gm-Gg: Acq92OHV8YjDFkAtNjLv9+Mbi6+ODAhGCgKoHZdfMKhCVaT23w2t0r+zyvG3EPwdBHg cbuf6oC+I4rmDHW5Alz0M47/KUsLL8P8vC55TwOW+tKt7ZtslPThRDFq9o4KCqwXM0Hx00bEjXm R6ENZEEnFLDpLmaCWSA3Dz2xLQlLKBOUbAxc7P467UMEl9P7sDNDi1i7qpgcyjzwoxZoeVNla7H +zC9sSChPdO6LR0TpJ6NxBAefObbRE1DdqcVAkNJUmCtwIKVX//mwv6a2KXQK7GZfQ/BSdFIfOM 2NXfiAVmB3x99ErDRpetZKeA7rIOqxsH3SCTbPCOKO2s205ouV2wCyy0rNLb6cTEDau9dUdFFLg fBqZE/BgZe0ecs3aVRuYglYLQCLKI49fVNcGe9dRHVqVFZx5n0lOoM1D9jeFJ1kPG0yf7d1Y+pb dlu14Pb9HGo7khClNX60ccYz/sNzI7jgErtDtbei7v8xvtPozm4fojpB0tnrvSZKMf8+9Iitm0V iij X-Received: by 2002:a05:690c:6081:b0:79a:daf7:c4fb with SMTP id 00721157ae682-7c95c6f6c02mr86221947b3.50.1778938869570; Sat, 16 May 2026 06:41:09 -0700 (PDT) Received: from gmail.com (172.235.85.34.bc.googleusercontent.com. [34.85.235.172]) by smtp.gmail.com with ESMTPSA id 00721157ae682-7c7f54c29ddsm44414217b3.34.2026.05.16.06.41.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 16 May 2026 06:41:07 -0700 (PDT) Date: Sat, 16 May 2026 09:41:07 -0400 From: Willem de Bruijn To: Jakub Kicinski , Qi Tang Cc: "David S . Miller" , David Ahern , Eric Dumazet , Paolo Abeni , Simon Horman , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: In-Reply-To: <20260515175522.0aafbfb4@kernel.org> References: <20260514035802.1540395-1-tpluszz77@gmail.com> <20260515175522.0aafbfb4@kernel.org> Subject: Re: [PATCH net v4] ipv6: validate extension header length before copying to cmsg Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Jakub Kicinski wrote: > On Thu, 14 May 2026 11:58:02 +0800 Qi Tang wrote: > > + return (ptr + len <= skb_tail_pointer(skb)) ? len : 0; > > This is probably better written as: > > return (len <= skb_tail_pointer(skb) - ptr) ? len : 0; > > ? len can't be too large so unlikely to matter in practice > but technically ptr + len may overflow and wrap on 32b? If making changes, also time to replace the open coded offset with sizeof ipv6_opt_hdr and opt_hdr->hdrlen? Or perhaps better left for net-next.