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 X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1DBE6C2D0A3 for ; Wed, 4 Nov 2020 17:03:31 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A320A20732 for ; Wed, 4 Nov 2020 17:03:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="1a3tDTsx"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="cbMszixD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A320A20732 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=MjpAoR84lNr1h866wNQhIkjwplnYb/TEBoD/Eze6xcc=; b=1a3tDTsxi2rRfMar98Q6hXE// lkfy6BdqE6BE0voVNjdbXQKRvzW7rAMDictY7kwgSasK3olnfG8IEhhYOu0nOQorgakfdW2KK37e2 RzrnK3a5M5IMsCw1nGl8XSzvuxIvG3akK2MYERHNNiBbjelcaWJ3bhzVpQ/HShuofNXgl3ZEsuOie ++X8WodbJ1k9+yWg7wl+F5sxYltte03C9Qj2qBwIavteRR5eKMx8LC+EscqxspJmxOP4Gq8h4JD2N H9UrBjDjTkt6eGeoH8KtAdhBo7AEwlb6rXcNy3ZV+QGhZwV3bJIgtkt2mltV/dlJUKwdNGD/dVKi7 E3RrPMwHA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kaMBk-0003E9-Ki; Wed, 04 Nov 2020 17:03:12 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kaMBd-0003Bn-KJ; Wed, 04 Nov 2020 17:03:06 +0000 Received: from kernel.org (unknown [87.71.17.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8FD9C2071A; Wed, 4 Nov 2020 17:02:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604509384; bh=rNITg8eagPnFNzCzxObVDyyyLvNDMpMqrDKWRtXNo1Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cbMszixDY/CCQ4Uoej0yke6wNx2huYgP8NhaGqEXUCQOQ+71BtRjL4UN747/oLhHT jlOUbEPtbSsAUpPtJ4TKfNUm3RxZ3UFt+v7azAmQtFc9r46TIiMsgPqIFvZ1tNT9dj lpdbGPMmI1FpQwRmAzKJsAvG+FlUBcvCqAD3nWrU= Date: Wed, 4 Nov 2020 19:02:47 +0200 From: Mike Rapoport To: Hagen Paul Pfeifer Subject: Re: [PATCH v6 0/6] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: <20201104170247.GT4879@kernel.org> References: <20200924132904.1391-1-rppt@kernel.org> <20201101110935.GA4105325@laniakea> <20201102154028.GD4879@kernel.org> <1547601988.128687.1604411534845@office.mailbox.org> <20201103163002.GK4879@kernel.org> <1988407921.138656.1604489953944@office.mailbox.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1988407921.138656.1604489953944@office.mailbox.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201104_120305_862509_447B6276 X-CRM114-Status: GOOD ( 25.08 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , David Hildenbrand , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, Will Deacon , linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Idan Yaniv , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Shuah Khan , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Arnd Bergmann , James Bottomley , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Andrew Morton Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Archived-At: List-Archive: On Wed, Nov 04, 2020 at 12:39:13PM +0100, Hagen Paul Pfeifer wrote: > > On 11/03/2020 5:30 PM Mike Rapoport wrote: > > > > > > As long as the task share the file descriptor, they can share the > > > > secretmem pages, pretty much like normal memfd. > > > > > > Including process_vm_readv() and process_vm_writev()? Let's take a hypothetical > > > "dbus-daemon-secure" service that receives data from process A and wants to > > > copy/distribute it to data areas of N other processes. Much like dbus but without > > > SOCK_DGRAM rather direct copy into secretmem/mmap pages (ring-buffer). Should be > > > possible, right? > > > > I'm not sure I follow you here. > > For process_vm_readv() and process_vm_writev() secremem will be only > > accessible on the local part, but not on the remote. > > So copying data to secretmem pages using process_vm_writev wouldn't > > work. > > A hypothetical "dbus-daemon-secure" service will not be *process related* with communication > peers. E.g. a password-input process (reading a password into secured-memory page) will > transfer the password to dbus-daemon-secure and this service will hand-over the password to > two additional applications: a IPsec process on CPU0 und CPU1 (which itself use a > secured-memory page). > > So four applications IPC chain: > password-input -> dbus-daemon-secure -> {IPsec0, IPsec1} > > - password-input: uses a secured page to read/save the password locally after reading from TTY > - dbus-daemon-secure: uses a secured page for IPC (legitimate user can write and read into the secured page) > - IPSecN has secured page to save the password locally (and probably other data as well), IPC memory is memset'ed after copy > > Goal: the whole password is never saved/touched on non secured pages during IPC transfer. > > Question: maybe a *file-descriptor passing* mechanism can do the trick? I.e. dbus-daemon-secure > allocates via memfd_secret/mmap secure pages and permitted processes will get the descriptor/mmaped-page > passed so they can use the pages directly? Yes, this will work. The processes that share the memfd_secret file descriptor will have access to the same memory pages, pretty much like with shared memory. > Hagen -- Sincerely yours, Mike. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv