From owner-freebsd-current@freebsd.org Mon Jan 4 20:43:54 2021 Return-Path: Delivered-To: freebsd-current@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 B34974CA19C for ; Mon, 4 Jan 2021 20:43:54 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from phk.freebsd.dk (phk.freebsd.dk [130.225.244.222]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4D8nfK5TPnz4T7T for ; Mon, 4 Jan 2021 20:43:53 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (v-critter.freebsd.dk [192.168.55.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by phk.freebsd.dk (Postfix) with ESMTPS id 702528A3C6; Mon, 4 Jan 2021 20:43:51 +0000 (UTC) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.16.1/8.16.1) with ESMTPS id 104Khp7G095363 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 4 Jan 2021 20:43:51 GMT (envelope-from phk@critter.freebsd.dk) Received: (from phk@localhost) by critter.freebsd.dk (8.16.1/8.16.1/Submit) id 104Khna7095362; Mon, 4 Jan 2021 20:43:49 GMT (envelope-from phk) To: John-Mark Gurney cc: RW , freebsd-current@freebsd.org Subject: Re: HEADS UP: FreeBSD src repo transitioning to git this weekend In-reply-to: <20210104193237.GD31099@funkthat.com> From: "Poul-Henning Kamp" References: <20201218182820.1P0tK%steffen@sdaoden.eu> <20201223023242.GG31099@funkthat.com> <20201223162417.v7Ce6%steffen@sdaoden.eu> <20201229011939.GU31099@funkthat.com> <20201229210454.Lh4y_%steffen@sdaoden.eu> <20201230004620.GB31099@funkthat.com> <20201231193908.GC31099@funkthat.com> <20210101165651.7319af5a@gumby.homeunix.com> <20210104193237.GD31099@funkthat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <95360.1609793029.1@critter.freebsd.dk> Date: Mon, 04 Jan 2021 20:43:49 +0000 Message-ID: <95361.1609793029@critter.freebsd.dk> X-Rspamd-Queue-Id: 4D8nfK5TPnz4T7T X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.00 / 15.00]; RCVD_TLS_ALL(0.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[130.225.244.222:from]; FREEFALL_USER(0.00)[phk]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+mx]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[freebsd.dk]; ARC_NA(0.00)[]; SPAMHAUS_ZRD(0.00)[130.225.244.222:from:127.0.2.255]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FORGED_SENDER(0.30)[phk@phk.freebsd.dk,phk@critter.freebsd.dk]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:1835, ipnet:130.225.0.0/16, country:EU]; FROM_NEQ_ENVFROM(0.00)[phk@phk.freebsd.dk,phk@critter.freebsd.dk]; MAILMAN_DEST(0.00)[freebsd-current]; FREEMAIL_CC(0.00)[googlemail.com,freebsd.org] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Jan 2021 20:43:54 -0000 -------- John-Mark Gurney writes: > SHAttered[1] (2017) created two valid PDF documents which had the same > SHA-1 hash. The issue was that they were able to choose the entire > document. Shattered is less impressive when you take into account that you can stuff as much much garbage into a PDF file as you need, without affecting the files normal function. Compact data formats, formats which leave no wiggle-room and do not offer extension-space for "attic-junk", are much harder to produce *meaningful* collisions for. (I take no opinion in where git is on that spectrum.) This is why I am very sceptical of the recent fashion of "GREASING" which the TLS WG have invented: To me that sounds like somebody is allocating wiggle-room for advanced cryptographic skullduggery. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.