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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F865EB64DD for ; Tue, 1 Aug 2023 08:11:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232130AbjHAIL3 (ORCPT ); Tue, 1 Aug 2023 04:11:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230100AbjHAILY (ORCPT ); Tue, 1 Aug 2023 04:11:24 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C73B611D; Tue, 1 Aug 2023 01:11:23 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4D623614A6; Tue, 1 Aug 2023 08:11:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0373C433C8; Tue, 1 Aug 2023 08:11:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690877482; bh=OWZu55Ufaewrwq61zbQVPkXisyIVRzmtL9NXkGrrT08=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EVLDGFUjKNL9YQvEJbi0QhgdkVVETRueKCZ2xE2fcWVDSDYQjcZ3ajuQn8FA75WES QzJwkFIXIl53Hvt9giwEdNL08L9HRCrKEw4pZ3ieIyitW1B3bSZIIFjA1DSdoNNZsO /gxpzFmZuvW72e6fhmdqoFGybN5rw84F3gdG4ydJcOjopWXtNHsCtQeEqkrVAl4lRv Y9Ym7C7ibhuPCPwt2u0ZfZG66iMhiW0nNoAUH5NhRTGaeHmvy2GlP37pDtSuU2Q710 wcoQYCuFKCk0tVd78iILIpWMKQLDwpnMM8MpM3+shJ4ZL6N4nv2nfQX6Fv/4tENdGt 133UkLROCpQ1Q== Date: Tue, 1 Aug 2023 11:11:17 +0300 From: Leon Romanovsky To: Jakub Kicinski Cc: Lin Ma , davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, fw@strlen.de, yang.lee@linux.alibaba.com, jgg@ziepe.ca, markzhang@nvidia.com, phaddad@nvidia.com, yuancan@huawei.com, ohartoov@nvidia.com, chenzhongjin@huawei.com, aharonl@nvidia.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [PATCH net v1 1/2] netlink: let len field used to parse type-not-care nested attrs Message-ID: <20230801081117.GA53714@unreal> References: <20230731121247.3972783-1-linma@zju.edu.cn> <20230731120326.6bdd5bf9@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230731120326.6bdd5bf9@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 31, 2023 at 12:03:26PM -0700, Jakub Kicinski wrote: > On Mon, 31 Jul 2023 20:12:47 +0800 Lin Ma wrote: > > In short, the very direct idea to fix such lengh-check-forgotten bug is > > add nla_len() checks like > > > > if (nla_len(nla) < SOME_LEN) > > return -EINVAL; > > > > However, this is tedious and just like Leon said: add another layer of > > cabal knowledge. The better solution should leverage the nla_policy and > > discard nlattr whose length is invalid when doing parsing. That is, we > > should defined a nested_policy for the X above like > > Hard no. Putting array index into attr type is an advanced case and the > parsing code has to be able to deal with low level netlink details. Jakub, IMHO, you are lowering too much the separation line between simple vs. advanced use cases. I had no idea that my use-case of passing nested netlink array is counted as advanced usage. Thanks