From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x230.google.com (mail-lf0-x230.google.com [IPv6:2a00:1450:4010:c07::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A30D03B29E for ; Tue, 2 Jan 2018 14:06:14 -0500 (EST) Received: by mail-lf0-x230.google.com with SMTP id u84so36685321lff.7 for ; Tue, 02 Jan 2018 11:06:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=ZaRmLRKHvVNa0vBsEyyA2qrJ3/7aJWk6oX0XYEOo71Y=; b=o+MMZQUKWkPGAR0UPoxqq+3SCB03N8xzrp5YP8P2zmLibqfZZ8sFsnvYwQArwRKaAh 0GNY4+euE1vsikK3YAIrtEUlfhtL/SU439kkAr83VETNATHXgpZkuZQMn+bG8OEbqr2B jngrvEXusN9q0EYBR3V8+YgIbSNA/e37sW4dHHsTG06xiIaS0lJCEsajcvv2AlMLBR2y k6fVpWi29FgBxdAO/MY3L4EsHC/JU1Zq+0tlsqbCgE7XK6Xe3qcVwwCP2IBvdaUr4eLn IjC03nkoMNdPL/+a4B8+bOUqTQieAYM1W4FOQaXRhXU0JkIrHD7lqRkJFXJYPDmXvZZo huiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=ZaRmLRKHvVNa0vBsEyyA2qrJ3/7aJWk6oX0XYEOo71Y=; b=BYWATU1g9qtjY/Y9RwIazegScdZHreqOl4BrLBnUhy9ea1CMybysI7ZdNyy9ZBFBhk fbR3bvOONAEtIMOI4TIBxN7Hr9lzyQK/YmvI33ibxKVDWtkXEuj/e8hPAlV17hVXL+2y 8NRVxzPl/m4k6YSk6HZO+VOgkpAyzOlyLghpDKpAel3IOIcx4T0s16CFfs+1Qxb/krdD ljRbxym5VwXoISwPFKMjso1tgkk1VaTueUpOfAeX9aj9WS7zKwqsCwSwTtHPWim+6x/s Vw8bZeUhiX9jNdIqiIvJIeuq3GuZ4oMKvrwd8xBDRNG2+2L3l7UU+JJ6mfjz4HmTwr87 1XVQ== X-Gm-Message-State: AKGB3mKEx8gJkAk+d8DLviXjlyWfPxIrMJe5nXCvLjtTEMBz1uveBJp6 ZbUspYtKTagPEvkzL1SJy5o= X-Google-Smtp-Source: ACJfBovxPrPL1q7dyX4do9npsZ2iAtx/otq2LAD2eOuljPZe+8jPxuHbDbWVDzutRcSe2Py2vzHxUg== X-Received: by 10.25.202.8 with SMTP id a8mr17164987lfg.11.1514919973462; Tue, 02 Jan 2018 11:06:13 -0800 (PST) Received: from [192.168.239.216] (mobile-access-bceee7-52.dhcp.inet.fi. [188.238.231.52]) by smtp.gmail.com with ESMTPSA id s5sm3869651lfb.29.2018.01.02.11.06.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Jan 2018 11:06:12 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.2 \(3445.5.20\)) From: Jonathan Morton In-Reply-To: Date: Tue, 2 Jan 2018 21:06:11 +0200 Cc: cerowrt-devel@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: References: To: Dave Taht X-Mailer: Apple Mail (2.3445.5.20) Subject: Re: [Cerowrt-devel] KASLR: Do we have to worry about other arches than x86? X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Jan 2018 19:06:14 -0000 As I thought: https://lkml.org/lkml/2017/12/27/2 "AMD processors are not subject to the types of attacks that the kernel page table isolation feature protects against. The AMD = microarchitecture does not allow memory references, including speculative references, that access higher privileged data when running in a lesser privileged mode when that access would result in a page fault." So it only affects *Intel* CPUs, though it's not yet clear to me how = widespread the bug is in Intel-land. Therefore ARM, PPC, etc are = unaffected, and AMD might just get even more of a leg up in the server = biz than previously anticipated. Reading between the lines, I get the definite impression that this is a = hardware exploit which uses *speculative* memory accesses to perform = Rowhammer attacks in privileged memory areas. So we probably shouldn't = worry about it too much on consumer PCs or routers, even if they do use = Intel x86 CPUs, except for the performance impact we might see where the = mitigation is in place. The performance impact would primarily affect = system calls and context switches, I think, with much less impact on = general computation. - Jonathan Morton