From owner-freebsd-hackers@freebsd.org Sat May 16 15:18:29 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 35F522F4CEC; Sat, 16 May 2020 15:18:29 +0000 (UTC) (envelope-from jhs@berklix.com) Received: from slim.berklix.org (slim.berklix.org [94.185.90.68]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "slim.berklix.org", Issuer "slim.berklix.org" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 49PTSN26wTz4c9Q; Sat, 16 May 2020 15:18:27 +0000 (UTC) (envelope-from jhs@berklix.com) Received: from mart.js.berklix.net (p2E52C9E4.dip0.t-ipconnect.de [46.82.201.228]) (authenticated bits=128) by slim.berklix.org (8.15.2/8.15.2) with ESMTPSA id 04GFIKf2080724 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 16 May 2020 17:18:24 +0200 (CEST) (envelope-from jhs@berklix.com) Received: from fire.js.berklix.net (fire.js.berklix.net [192.168.91.41]) by mart.js.berklix.net (8.14.3/8.14.3) with ESMTP id 04GFIK98007397; Sat, 16 May 2020 17:18:20 +0200 (CEST) (envelope-from jhs@berklix.com) Received: from fire.js.berklix.net (localhost [127.0.0.1]) by fire.js.berklix.net (8.14.7/8.14.7) with ESMTP id 04GFIA0a099390; Sat, 16 May 2020 17:18:20 +0200 (CEST) (envelope-from jhs@berklix.com) Message-Id: <202005161518.04GFIA0a099390@fire.js.berklix.net> To: freebsd-arch@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: [HEADSUP] Disallowing read() of a directory fd From: "Julian H. Stacey" Organization: http://berklix.com/jhs http://stolenvotes.uk User-agent: EXMH on FreeBSD http://berklix.com/free/ X-From: http://www.berklix.org/~jhs/ In-reply-to: Your message "Fri, 15 May 2020 20:30:08 -0700." <2ea8236f935a4c786a0f4f06ca1d3ea3@udns.ultimatedns.net> Date: Sat, 16 May 2020 17:18:10 +0200 X-Rspamd-Queue-Id: 49PTSN26wTz4c9Q X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of jhs@berklix.com has no SPF policy when checking 94.185.90.68) smtp.mailfrom=jhs@berklix.com X-Spamd-Result: default: False [-0.12 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; NEURAL_HAM_MEDIUM(-0.81)[-0.815,0]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-0.20)[-0.200,0]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; DMARC_NA(0.00)[berklix.com]; AUTH_NA(1.00)[]; HAS_ORG_HEADER(0.00)[]; RCVD_COUNT_THREE(0.00)[4]; IP_SCORE(-0.00)[ip: (0.01), ipnet: 94.185.88.0/22(0.01), asn: 33824(-0.00), country: DE(-0.02)]; RCPT_COUNT_TWO(0.00)[2]; RCVD_IN_DNSWL_NONE(0.00)[68.90.185.94.list.dnswl.org : 127.0.10.0]; R_SPF_NA(0.00)[]; RECEIVED_SPAMHAUS_PBL(0.00)[228.201.82.46.khpj7ygk5idzvmvt5x4ziurxhy.zen.dq.spamhaus.net : 127.0.0.10]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:33824, ipnet:94.185.88.0/22, country:DE]; RCVD_TLS_LAST(0.00)[]; FROM_EQ_ENVFROM(0.00)[] 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: Sat, 16 May 2020 15:18:29 -0000 Another use of "cat ." is to see names of transient files a tool creates, & normaly deletes, if not aborting, so one can find same name junk elsewhere, & search for tool causing junk, & ensure other data files avoid using names that would be zapped. While blocking "cat ." might be worked round if not in a jail, & or if using fsdb & sysctl etc, it would add to a more BSD specific environment, where standard portable Unix skills was insufficient, & more time needed to search & learn BSD extras. Every obstacle costs employers time = money. Cheers -- Julian Stacey, Consultant Systems Engineer, BSD Linux http://berklix.com/jhs/ http://www.berklix.org/corona/#masks Tie 2 handkerchiefs or 1 pillow case. Jobs & economy hit by Corona to be hit again by Crash Brexit 31st Dec. 2020