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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham 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 1B91CC43334 for ; Wed, 5 Sep 2018 07:52:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7A012073D for ; Wed, 5 Sep 2018 07:52:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="1L4BEoJq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7A012073D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727760AbeIEMVp (ORCPT ); Wed, 5 Sep 2018 08:21:45 -0400 Received: from merlin.infradead.org ([205.233.59.134]:57914 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726369AbeIEMVp (ORCPT ); Wed, 5 Sep 2018 08:21:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=qhzfZW+9aQS7VMMF3q18FnhsfKlwAziHfmHjOfyfhig=; b=1L4BEoJqpWnsC8cyD4/tuBq3y Tb6+F0YLqA7C2vXHSo0V2F8+rxPc1z974m/CBnNDmJeiCpsjSsDKlJt2hUbMloUUWM8mNwqJSX+iN GC+zIJmE+UD+rOlI2nRoV4R7qyIsdo1sLWo3RhACxwaSnAtHz9gELNO+2s57AlVTk8zFyZDvJADDI wd27sGW3YmpzXD2JQoZIq6ktTjmPACuo8WnGUp5KNtQCghZhjQcYPNIehq8eRqdAXdOQjpCveF4FA mjJmFF0zQHljf8dD+OghOZzok1g16R4LVsYOm15fL9Q3BzguJujRqRAFKqCJtG8vy9AAeNJls0C7p tvQDYh1bw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fxScE-0003iQ-2e; Wed, 05 Sep 2018 07:52:42 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5587C20191BFF; Wed, 5 Sep 2018 09:52:38 +0200 (CEST) Date: Wed, 5 Sep 2018 09:52:38 +0200 From: Peter Zijlstra To: Jiri Kosina Cc: Thomas Gleixner , Ingo Molnar , Josh Poimboeuf , Andrea Arcangeli , "Woodhouse, David" , Oleg Nesterov , Tim Chen , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v3 2/3] x86/speculation: apply IBPB more strictly to avoid cross-process data leak Message-ID: <20180905075238.GN24124@hirez.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 04, 2018 at 04:42:02PM +0200, Jiri Kosina wrote: > if (tsk && tsk->mm && > tsk->mm->context.ctx_id != last_ctx_id && > - get_dumpable(tsk->mm) != SUID_DUMP_USER) > + ___ptrace_may_access(current, tsk, PTRACE_MODE_IBPB)) > indirect_branch_prediction_barrier(); See how the new (first) argument is 'current' and you could've just used the old __ptrace_may_access().