From owner-freebsd-hackers@freebsd.org Fri May 15 17:50:09 2020 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id B91CE2FBEDF for ; Fri, 15 May 2020 17:50:09 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Received: from mail-il1-f179.google.com (mail-il1-f179.google.com [209.85.166.179]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49Nwsr5N60z4CJq for ; Fri, 15 May 2020 17:50:08 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Received: by mail-il1-f179.google.com with SMTP id q10so3440391ile.0 for ; Fri, 15 May 2020 10:50:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Ez/SLyrOgfpo3/NAtV7IRm6bJ9F1C0fcTHpIjg1lgwo=; b=KwIlJtW6X2ps+3mlfh7GLV9BDtfDNw50LOH376baNaOKxkhNI9koiw5PgFtupg6/vW +/Eg0Zcvu3lMHJOVLfbzQO+az6pDjFCzo1M4KHSoO5cAUtsvHX+r66wj2RwStfeNs1J2 YqswQCAVF5h+IQkx+VMdNH3sq+wwlASrHo1zM8W4253gQbg7vB8lrtNUsw7vvICXSbt6 ms2/icI5XtT5CMXM8LyNow67lBKcF3FgN2rladPxE81UOW/J82N/JDEJCbw1TLonMom5 Rn5Jf4auSwYJ6urhj78tcP9gqzovlbDX7xGUFC4UH4VZCmXeUeO8UcMxlWA72Smzis1G V0Lg== X-Gm-Message-State: AOAM530J+rAqcRMwqGdXjhhY/QMdPuJR5SgYnk5tZJUw5F7bac7Z6Zyy DDhzgzUMQ4GpPv2LLg3eNjlUoFdRVwfMXwM4GhtJzrbFroA= X-Google-Smtp-Source: ABdhPJyhuOU+H3tcJj0AuNQMYJG/wzeyHaiR00jowyxKPLZY6Bh4sUpBgm7VzmenYeFpYzb28MVL1M3JY0ZSUI4avww= X-Received: by 2002:a92:c952:: with SMTP id i18mr4776036ilq.100.1589565007503; Fri, 15 May 2020 10:50:07 -0700 (PDT) MIME-Version: 1.0 References: <20200515150627.GY82984@trajan.stk.cx> <02cb48c24a3d010dab13974680dc3d16@udns.ultimatedns.net> In-Reply-To: <02cb48c24a3d010dab13974680dc3d16@udns.ultimatedns.net> From: Ed Maste Date: Fri, 15 May 2020 13:49:54 -0400 Message-ID: Subject: Re: [HEADSUP] Disallowing read() of a directory fd To: bsd-lists@bsdforge.com Cc: FreeBSD Hackers Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 49Nwsr5N60z4CJq X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of carpeddiem@gmail.com designates 209.85.166.179 as permitted sender) smtp.mailfrom=carpeddiem@gmail.com X-Spamd-Result: default: False [-3.43 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:209.85.128.0/17]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; DMARC_NA(0.00)[freebsd.org]; MIME_TRACE(0.00)[0:+]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; RCVD_IN_DNSWL_NONE(0.00)[179.166.85.209.list.dnswl.org : 127.0.5.0]; IP_SCORE(-1.43)[ip: (-6.28), ipnet: 209.85.128.0/17(-0.39), asn: 15169(-0.42), country: US(-0.05)]; FORGED_SENDER(0.30)[emaste@freebsd.org,carpeddiem@gmail.com]; RWL_MAILSPIKE_POSSIBLE(0.00)[179.166.85.209.rep.mailspike.net : 127.0.0.17]; R_DKIM_NA(0.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US]; FROM_NEQ_ENVFROM(0.00)[emaste@freebsd.org,carpeddiem@gmail.com]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 15 May 2020 17:50:09 -0000 On Fri, 15 May 2020 at 13:14, Chris wrote: > > But given the potential > gains for all this, are trivial at best. Some benefits of this change have already been discussed: 1. It would have prevented, or at least significantly blunted, the security issue described in FreeBSD-SA-19:10.ufs. 2. It avoids problems caused by application assumptions. On the other hand, arguments for allowing reads of directories: 1. It's always been that way. 2. File system developers and experts may use the ability for certain special or unusual actions. Making the change with a sysctl to control still allows the special case use, and I'm glad that Kyle spent the time on this change.