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=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_NEOMUTT autolearn=ham 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 B83F0C169C4 for ; Mon, 11 Feb 2019 21:32:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 867332184A for ; Mon, 11 Feb 2019 21:32:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=brauner.io header.i=@brauner.io header.b="LR5JdxAk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727520AbfBKVcy (ORCPT ); Mon, 11 Feb 2019 16:32:54 -0500 Received: from mail-ed1-f66.google.com ([209.85.208.66]:43961 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726140AbfBKVcx (ORCPT ); Mon, 11 Feb 2019 16:32:53 -0500 Received: by mail-ed1-f66.google.com with SMTP id f9so336395eds.10 for ; Mon, 11 Feb 2019 13:32:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=brauner.io; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=V6d1YLoUREI+bC7/ZgN7EbrA9AS3ePXM4h7fJTU7/Ag=; b=LR5JdxAkM1ux2oT8XwGcTR12jwH3rBhGGwkRoyMK37zGBdQCwAY5blifNd/L7wXp0r n9iTac+tf+FJw/T6x72Mq5apabbcjkb2io7XI4UNcz/92sJm59QYDWhldmA8YioDBJB9 xwXq2NgvwD6AwF8kYobw0vt0fnYMHqz7RM/ShxtwfhaQSLx5vqR4PodXkbjq5+4dkwjA /kaE2455EFAycgHJq/xO4f1BkO2hvupUepHtGZF07TUPevXxUwm/7COaR9C0O7NkZtwT V1dhqbw2sNeV/FMhPVNjNRLxrprdzxA7QvfQfKa24zPLDnPEtwZzXjL4UhI5i1IivXc9 NIXw== 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:references :mime-version:content-disposition:in-reply-to:user-agent; bh=V6d1YLoUREI+bC7/ZgN7EbrA9AS3ePXM4h7fJTU7/Ag=; b=Mf7hhN8220oRc4w2NrbUCsZ/S5YjB+s1oQf6XnSKGQ/CUdQ7IIZfSXeuOA6XjnphdX tvkSEeZKAYsTRJRAfIbfsLmB5YIO5yHbRhctuSKdj43+tNEamIRvanjyP/73l1KUSo7h TV+piJ0+1R4fPemYPKPh/Ylkwxsifc80nRVUsiSOvo1wnraSHcG7vkzA0jIULZiSkpue 1FoZDTNJZoRAv2N1I4FmzB/XlwtUXk+nvhW/zV7TijRosVx0y89unYGgTo1qNigOa9KR LKeocP6TwKj+zJ5OFyBIEfowmRunVXfaEOBBDjLvcNW6k1X/n+KRB231fMCAZpXeU84E CiRw== X-Gm-Message-State: AHQUAubI6SEtHh4UArLshWyDj0qaXYIa7SQ3ZkAKJqLr3JlNxfpyBPUw lPObO7vRlbzkgHtBpR/INemORA== X-Google-Smtp-Source: AHgI3Iaa9RUHWVuM61yGq2/vBVsDXMFFWFDynpx2M90MaSFHH1vYN90tG/K382GQeBEdx7mpP6WMFw== X-Received: by 2002:aa7:ce13:: with SMTP id d19mr205830edv.15.1549920771990; Mon, 11 Feb 2019 13:32:51 -0800 (PST) Received: from brauner.io ([2a02:8109:b6c0:76e:9ed:e1af:663e:9c0b]) by smtp.gmail.com with ESMTPSA id f1sm1689620ejl.65.2019.02.11.13.32.50 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 11 Feb 2019 13:32:51 -0800 (PST) Date: Mon, 11 Feb 2019 22:32:50 +0100 From: Christian Brauner To: Luis Chamberlain Cc: Alexey Dobriyan , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, longman@redhat.com, linux@dominikbrodowski.net, keescook@chromium.org, joe.lawrence@redhat.com, ebiederm@xmission.com, linux-api@vger.kernel.org Subject: Re: + sysctl-return-einval-if-val-violates-minmax.patch added to -mm tree Message-ID: <20190211213249.lta2pithpf5w6w7m@brauner.io> References: <20190211210632.Nfd0f%akpm@linux-foundation.org> <20190211211716.GA31039@avx2> <20190211211917.kq2ahdkhoe36obhp@brauner.io> <20190211212523.GU11489@garbanzo.do-not-panic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190211212523.GU11489@garbanzo.do-not-panic.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 11, 2019 at 01:25:23PM -0800, Luis Chamberlain wrote: > On Mon, Feb 11, 2019 at 10:19:19PM +0100, Christian Brauner wrote: > > On Tue, Feb 12, 2019 at 12:17:16AM +0300, Alexey Dobriyan wrote: > > > On Mon, Feb 11, 2019 at 01:06:32PM -0800, akpm@linux-foundation.org wrote: > > > > > > > @@ -2848,8 +2848,10 @@ static int __do_proc_doulongvec_minmax(v > > > > > > > - if ((min && val < *min) || (max && val > *max)) > > > > - continue; > > > > + if ((min && val < *min) || (max && val > *max)) { > > > > + err = -EINVAL; > > > > > > I was asked to return ERANGE in kstrto*(). > > > > I think we discussed ERANGE vs EINVAL and decided EINVAL because there > > was precedence for other sysctls already. > > Can you do a proper audit and see? If you look at proc_get_long() right now you can see that when the buffer we use to parse the number is exceeded we return EINVAL. In short if you do right now: echo 1844674407370955161600000 > /proc/sys/fs/file-max that would exceed the buffer in proc_get_long() and you already get EINVAL for all such cases. If we now change this to ERANGE we would return: echo 18446744073709551616 > /proc/sys/fs/file-max -> ERANGE echo 1844674407370955161600000 > /proc/sys/fs/file-max -> EINVAL which would be very confusing. For consistency we should use EINVAL. See kernel/sysctl.c: /* We don't know if the next char is whitespace thus we may accept * invalid integers (e.g. 1234...a) or two integers instead of one * (e.g. 123...1). So lets not allow such large numbers. */ if (len == TMPBUFLEN - 1) return -EINVAL; Christian