From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by sourceware.org (Postfix) with ESMTPS id C80C43858C50 for ; Thu, 31 Mar 2022 04:45:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C80C43858C50 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 16D0BB81EC9 for ; Thu, 31 Mar 2022 04:45:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F561C340EE for ; Thu, 31 Mar 2022 04:45:48 +0000 (UTC) Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id e601afb3 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO) for ; Thu, 31 Mar 2022 04:45:46 +0000 (UTC) Received: by mail-yw1-f177.google.com with SMTP id 00721157ae682-2eafabbc80aso25614017b3.11 for ; Wed, 30 Mar 2022 21:45:45 -0700 (PDT) X-Gm-Message-State: AOAM531Fq9Dz0bnyyeWWrzD6bOlLYJa/GxCWs6KAzTXrivWwoW7BWvxb 4knfUo362vdHlG5ZkF9DtpYV64VnPMDDtmg6UEs= X-Google-Smtp-Source: ABdhPJymAbBdNcqysZzl6qBqp4EYO8K9TOh4tLBBHKWy0rERl6pv/m0ak6oW8K+6p0aM2xPwGw6G3X6GEpPdB/VVPXQ= X-Received: by 2002:a81:370a:0:b0:2ea:25ed:41a1 with SMTP id e10-20020a81370a000000b002ea25ed41a1mr3602953ywa.404.1648701944851; Wed, 30 Mar 2022 21:45:44 -0700 (PDT) MIME-Version: 1.0 References: <20220328220936.2724834-1-goldstein.w.n@gmail.com> <7b48ece6-392a-0850-c136-01ab751273ef@linaro.org> <72332228-093c-5186-789f-8616cfb93793@linaro.org> In-Reply-To: From: "Jason A. Donenfeld" Date: Thu, 31 Mar 2022 00:45:33 -0400 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 1/2] random-bits: Factor out entropy generating function To: crrodriguez@opensuse.org Cc: Noah Goldstein , Adhemerval Zanella , GNU C Library , Florian Weimer Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 31 Mar 2022 04:45:53 -0000 Hi Christian, Thanks for looping me into this thread. On Wed, Mar 30, 2022 at 3:38 PM Cristian Rodr=C3=ADguez wrote: > > On Wed, Mar 30, 2022 at 1:30 PM Noah Goldstein via Libc-alpha > wrote: > > > Thanks, I can add patches for sparc/powerpc64le/ia64. Still feel that > > since it takes testing and there are optimization cases that we mayf > > want to make it's still best to have a seperate file. > > What is really needed is to get some sort of randomness function > exposed through the VDSO, so there is no syscall overhead and all this > magic can be dropped. I'm not even sure if that is possible. that or > a reliable prng usable even by the dynamic linker. Can someone provide some context on this? I've actually looked into having some megafast userspace RNG component in the vDSO, and I'm not fundamentally opposed to the idea. I think there's interesting potential there and something worth considering. But what's the context of you asking for this now? Under what circumstances are you finding that calling getrandom(0) or similar is too high overhead or otherwise problematic? Jason