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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A620C6FD1C for ; Wed, 22 Mar 2023 04:52:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229667AbjCVEwq (ORCPT ); Wed, 22 Mar 2023 00:52:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbjCVEwo (ORCPT ); Wed, 22 Mar 2023 00:52:44 -0400 X-Greylist: delayed 121 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 21 Mar 2023 21:52:42 PDT Received: from vimdzmsp-sfwd04.bluewin.ch (vimdzmsp-sfwd04.bluewin.ch [195.186.227.132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7B1025E0D for ; Tue, 21 Mar 2023 21:52:42 -0700 (PDT) Received: from [192.168.2.206] ([178.193.94.8]) by vimdzmsp-sfwd04.bluewin.ch Swisscom AG with ESMTPA id eqQop8vosSGmMeqQopHnhz; Wed, 22 Mar 2023 05:50:38 +0100 X-Bluewin-Spam-Analysis: v=2.4 cv=AqmNYMxP c=1 sm=1 tr=0 ts=641a891e a=HspnF00aK8asgizx1TveVQ==:117 a=HspnF00aK8asgizx1TveVQ==:17 a=IkcTkHD0fZMA:10 a=ag1SF4gXAAAA:8 a=VwQbUJbxAAAA:8 a=ErgUOLliWilC1Brv_bMA:9 a=QEXdDO2ut3YA:10 a=Yupwre4RP9_Eg_Bd0iYG:22 a=AjGcO6oz07-iQ99wixmX:22 X-Bluewin-Spam-Score: 0.00 X-FXIT-IP: IPv4[178.193.94.8] Epoch[1679460638] X-Bluewin-AuthAs: traian.teodorescu@bluewin.ch Message-ID: Date: Wed, 22 Mar 2023 05:51:10 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Content-Language: en-US To: linux-kernel@vger.kernel.org From: Traian Teodorescu Subject: Fwd: Linux entropy Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CMAE-Envelope: MS4xfNiPGdTdYqkq9qQsOs9+1AR0aBUsFUy/nUu/weNgi1/lD/M618XUSzZ/ztfsO+5SRPCr53zqK1xj0ezG68FzIgUoTbOTnIplLGTBuI4UXJ23JNvrLwUz 4pEiv6s/WZ+IhJZ0KxEDarq6dNDHAcN03wDC2GHlLLeZ2LI9+APxcQ49jixfK5A3mKRvYSgCVPF+tbAcMz+3ESTA5vBR2zeVLOo= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, I've been redirected by  the "friendly bot" to you (I've already looked into "kernelnewbies" but I didn't find a linked topic). I would want to know more about the subject below. Is there another possibility to read the value of current entropy in new versions of kernel ? Are the old services (as for instance haveged) still compatible ? Thank you and have a nice evening, Traian -------- Forwarded Message -------- Subject:     Linux entropy Date:     Tue, 21 Mar 2023 17:03:36 +0100 From:     Traian Teodorescu To:     gregkh@linuxfoundation.org Mr Kroah-Hartmann, I've recently discovered that the value containing the machine's entropy (in /proc/sys/kernel/random/entropy_avail ) isn't updated anymore on one of my machines. I found some articles on the Internet about this change, but nothing very "official". There is also an explanation at "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.15.y&id=e7e196e1ae2603a2c5f1894f1868a7a5b5a2c5e0" about keeping forward secrecy, etc, that I didn't really understood. I began using Linux since less than 10 years and I am not what you can call an experienced user, but from my point of view this change doesn't make sense. If I understand well some basic principles, Linux kernel is the only one meant to be accessible to everybody wanting to understand deeply how a modern OS works, so what's the gain in this "obfuscation" ?  From my point of view, a sysadmin should know how much entropy they have on their machines. So, please, can you please make some comments about this change ? (of eventually send me a link to an article that I can trust ?) I really enjoyed Linux a lot those years and I learned to appreciate it, so from this point of view I am grateful to the teams maintaining free software, so ... thank you ! Thanks for an eventual answer and have a nice evening, Traian