From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <pve-devel-bounces@lists.proxmox.com> Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) by lore.proxmox.com (Postfix) with ESMTPS id 319E41FF16F for <inbox@lore.proxmox.com>; Tue, 10 Jun 2025 16:04:00 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 297EF1DDD4; Tue, 10 Jun 2025 16:04:21 +0200 (CEST) Message-ID: <1474d1cb-cdf2-41a1-8fff-841c7f5c1cfc@proxmox.com> Date: Tue, 10 Jun 2025 16:03:47 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Proxmox VE development discussion <pve-devel@lists.proxmox.com> References: <20250603075558.627850-1-alexandre.derumier@groupe-cyllene.com> <mailman.237.1748948724.395.pve-devel@lists.proxmox.com> Content-Language: en-US From: Fiona Ebner <f.ebner@proxmox.com> In-Reply-To: <mailman.237.1748948724.395.pve-devel@lists.proxmox.com> X-SPAM-LEVEL: Spam detection results: 0 AWL -0.032 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_VALIDITY_CERTIFIED_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_RPBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_SAFE_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pve-devel] [PATCH qemu-server 01/13] blockdev: cmdline: add blockdev syntax support X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion <pve-devel.lists.proxmox.com> List-Unsubscribe: <https://lists.proxmox.com/cgi-bin/mailman/options/pve-devel>, <mailto:pve-devel-request@lists.proxmox.com?subject=unsubscribe> List-Archive: <http://lists.proxmox.com/pipermail/pve-devel/> List-Post: <mailto:pve-devel@lists.proxmox.com> List-Help: <mailto:pve-devel-request@lists.proxmox.com?subject=help> List-Subscribe: <https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel>, <mailto:pve-devel-request@lists.proxmox.com?subject=subscribe> Reply-To: Proxmox VE development discussion <pve-devel@lists.proxmox.com> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pve-devel-bounces@lists.proxmox.com Sender: "pve-devel" <pve-devel-bounces@lists.proxmox.com> The way the node name encoding is implemented is problematic as we operate outside of integer ranges: [I] febner@dev8 ~/repos/pve/qemu-server (qemu-blockdev-options)> cat asdf.pm use strict; use warnings; use Digest::SHA; sub encode_base62 { my ($input) = @_; my @chars = ('0'..'9', 'A'..'Z', 'a'..'z'); my $base = 62; my $value = 0; my $result = ''; for my $byte (unpack('C*', $input)) { $value = $value * 256 + $byte; print "$value\n"; } } encode_base62(Digest::SHA::sha1("foo")); [I] febner@dev8 ~/repos/pve/qemu-server (qemu-blockdev-options)> perl asdf.pm 11 3054 782023 200198069 51250705898 13120180709951 3358766261747471 859844163007352795 2.20120105729882e+20 5.63507470668499e+22 1.44257912491136e+25 3.69300255977307e+27 9.45408655301907e+29 2.42024615757288e+32 6.19583016338658e+34 1.58613252182696e+37 4.06049925587703e+39 1.03948780950452e+42 2.66108879233157e+44 6.81238730836881e+46 Also, while the use case here shouldn't be cryptographically sensitive, you never know, so I'll just use a different hash function than sha1. I'll cut off the result from that hash to 30 hex digits. Then we still have one letter for the prefix of the node name. As for collision probability, that will be 120 bits and should be more than enough, even 2^50 nodes have a very small probability to collide with that: >>> math.log2(16**30) 120.0 >>> d=2**120 >>> n=2**50 >>> 1 - math.exp(-(n*n)/(2*d)) 4.768370445162873e-07 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel