From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-3.7 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id 09D0E1F953 for ; Tue, 16 Nov 2021 16:01:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238768AbhKPQEi convert rfc822-to-8bit (ORCPT ); Tue, 16 Nov 2021 11:04:38 -0500 Received: from elephants.elehost.com ([216.66.27.132]:39735 "EHLO elephants.elehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238777AbhKPQEi (ORCPT ); Tue, 16 Nov 2021 11:04:38 -0500 X-Virus-Scanned: amavisd-new at elehost.com Received: from Mazikeen (cpe00fc8d49d843-cm00fc8d49d840.cpe.net.cable.rogers.com [99.229.22.139] (may be forged)) (authenticated bits=0) by elephants.elehost.com (8.15.2/8.15.2) with ESMTPSA id 1AGG1PKI056263 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 16 Nov 2021 11:01:25 -0500 (EST) (envelope-from rsbecker@nexbridge.com) Reply-To: From: To: "'Jeff King'" , "'brian m. carlson'" Cc: References: <20211116033542.3247094-1-sandals@crustytoothpaste.net> <20211116033542.3247094-2-sandals@crustytoothpaste.net> In-Reply-To: Subject: RE: [PATCH 1/2] wrapper: add a helper to generate numbers from a CSPRNG Date: Tue, 16 Nov 2021 11:01:20 -0500 Organization: Nexbridge Inc. Message-ID: <009d01d7db03$354ecae0$9fec60a0$@nexbridge.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT X-Mailer: Microsoft Outlook 16.0 Content-Language: en-ca Thread-Index: AQHRZsJQSwQVxvA803MGEaqTSKtEHwGUCvbjAr89fOqr8J3MYA== Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On November 16, 2021 10:31 AM, Jeff King wrote: > On Tue, Nov 16, 2021 at 03:35:41AM +0000, brian m. carlson wrote: > > > The order of options is also important here. On systems with > > arc4random, which is most of the BSDs, we use that, since, except on > > MirBSD, it uses ChaCha20, which is extremely fast, and sits entirely > > in userspace, avoiding a system call. We then prefer getrandom over > > getentropy, because the former has been available longer on Linux, and > > finally, if none of those are available, we use /dev/urandom, because > > most Unix-like operating systems provide that API. We prefer options > > that don't involve device files when possible because those work in > > some restricted environments where device files may not be available. > > I wonder if we'll need a low-quality fallback for older systems which don't > even have /dev/urandom. Because it's going to be used in such a core part of > the system (tempfiles), this basically becomes a hard requirement for using > Git at all. > > I can't say I'm excited in general to be introducing a dependency like this, just > because of the portability headaches. But it may be the least bad thing > (especially if we can fall back to the existing behavior). > One alternative would be to build on top of the system mkstemp(), which > makes it libc's problem. I'm not sure if we'd run into problems there, though. None of /dev/urandom, /dev/random, or mkstemp are available on some platforms, including NonStop. This is not a good dependency to add. One variant PRNGD is used in ia64 OpenSSL, while the CPU random generator in hardware is used on x86. I cannot get behind this at all. Libc is also not used in or available to our port. I am very worried about this direction. -Randall