From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752526AbdHIAwt (ORCPT ); Tue, 8 Aug 2017 20:52:49 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:57948 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752319AbdHIAwr (ORCPT ); Tue, 8 Aug 2017 20:52:47 -0400 Date: Tue, 08 Aug 2017 17:51:54 -0700 (PDT) Message-Id: <20170808.175154.286461828216806349.davem@davemloft.net> To: daniel@iogearbox.net Cc: ecree@solarflare.com, alexei.starovoitov@gmail.com, ast@fb.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, iovisor-dev@lists.iovisor.org Subject: Re: [PATCH v5 net-next 00/12] bpf: rewrite value tracking in verifier From: David Miller In-Reply-To: <598909D8.5060202@iogearbox.net> References: <598909D8.5060202@iogearbox.net> X-Mailer: Mew version 6.7 on Emacs 25.2 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 08 Aug 2017 17:52:47 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Daniel Borkmann Date: Tue, 08 Aug 2017 02:46:16 +0200 > On 08/07/2017 04:21 PM, Edward Cree wrote: >> This series simplifies alignment tracking, generalises bounds tracking >> and >> fixes some bounds-tracking bugs in the BPF verifier. Pointer >> arithmetic on >> packet pointers, stack pointers, map value pointers and context >> pointers has >> been unified, and bounds on these pointers are only checked when the >> pointer >> is dereferenced. >> Operations on pointers which destroy all relation to the original >> pointer >> (such as multiplies and shifts) are disallowed if >> !env->allow_ptr_leaks, >> otherwise they convert the pointer to an unknown scalar and feed it to >> the >> normal scalar arithmetic handling. >> Pointer types have been unified with the corresponding >> adjusted-pointer types >> where those existed (e.g. PTR_TO_MAP_VALUE[_ADJ] or FRAME_PTR vs >> PTR_TO_STACK); similarly, CONST_IMM and UNKNOWN_VALUE have been >> unified into >> SCALAR_VALUE. >> Pointer types (except CONST_PTR_TO_MAP, PTR_TO_MAP_VALUE_OR_NULL and >> PTR_TO_PACKET_END, which do not allow arithmetic) have a 'fixed >> offset' and >> a 'variable offset'; the former is used when e.g. adding an immediate >> or a >> known-constant register, as long as it does not overflow. Otherwise >> the >> latter is used, and any operation creating a new variable offset >> creates a >> new 'id' (and, for PTR_TO_PACKET, clears the 'range'). >> SCALAR_VALUEs use the 'variable offset' fields to track the range of >> possible >> values; the 'fixed offset' should never be set on a scalar. > > Been testing and reviewing the series over the last several days, > looks > reasonable to me as far as I can tell. Thanks for all the hard work on > unifying this, Edward! > > Acked-by: Daniel Borkmann Series applied, thanks everyone!