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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH autolearn=unavailable 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 9DA35C4321A for ; Mon, 10 Jun 2019 18:07:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 59189207E0 for ; Mon, 10 Jun 2019 18:07:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="bS38Kka2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59189207E0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DEA176B026A; Mon, 10 Jun 2019 14:07:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D9A786B026B; Mon, 10 Jun 2019 14:07:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C61E56B026C; Mon, 10 Jun 2019 14:07:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by kanga.kvack.org (Postfix) with ESMTP id 8CFB36B026A for ; Mon, 10 Jun 2019 14:07:07 -0400 (EDT) Received: by mail-pf1-f197.google.com with SMTP id i123so7704356pfb.19 for ; Mon, 10 Jun 2019 11:07:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:from:to:cc:subject :message-id:references:mime-version:content-disposition:in-reply-to; bh=Qk1teTE+M+IujpCJ4fnOYjeYPWGwjvW8JXrxo/yH0Jc=; b=ZbICKnPM71xM3qvCBQsQB4I97odTnYfSxtf404jFrvSV8TTdtZiTbsL0yJMkmP5bls 3d0Qv8e589e2jpZbMygetQfIofqdICNaLfe7li8r1ao0cOCyc94OmZNQRat8fER/a7Ml 4iUOIvsTL7uS4nKNGGJJ/8CfT+x2JKiFO46WhT0opaNIrw5qfB+2Gvf/lJnAUJpnB5UW zSO6u4lQvn11XYG4XZ6P/cUBQD1C+iAcWMi0nwCNb90uFlNEOqFym1bTvBQjAqxU818P mMQiFsfYqaAhvN+5Wl27eF64L22b0tehRUM4TGwXWAOb+9ClG2VDeiJyL3wM6K92Kxz8 AYiA== X-Gm-Message-State: APjAAAVUF+GFJFZMGUO9E4Gh9DtQ2rPWRAwcZ8sY2sOhkISOgn8f8XTh hvnQoBsxdXSM3uX2IwIwmVzoR//r91JlZa1KUsNl6vrHRrETwzfKzZbffa3XW14goMRAjIRZY+k CvQJnKQoyJNkjPg8lA3tNQ7iSVE0xfO4zWLrg2OC8Vsc9Mh3DUY8giKhkl5lHARaGgg== X-Received: by 2002:a17:90a:9f90:: with SMTP id o16mr23049482pjp.72.1560190027135; Mon, 10 Jun 2019 11:07:07 -0700 (PDT) X-Received: by 2002:a17:90a:9f90:: with SMTP id o16mr23049415pjp.72.1560190026181; Mon, 10 Jun 2019 11:07:06 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1560190026; cv=none; d=google.com; s=arc-20160816; b=xULki7F3C5XGazOb2W974xNbNxVcnMYS7UUxq52Ipw6XsWFf2NEuo7xl5hago8RY5U ORMaNXnUVVUWJsf+FVZYeV7FGWvVf1M10cBm91KRReN5+jKBLjeuW+PzXlQErm9AZVUE RNoSImbQNb9agOwZkCZGpeH5MtgVZk3Q+mo6VaEqCYqhUvv5+LNYw5uYnRRtyN/ps93v gPAESrqj8+7Qn3GRQTwHmZvOhNFAzynS9WUlrV83QflnqlDH60wdQB8bFJYrLijCpi08 I689lORQaU8ZN1NgBaX5L6tt/3ITbmIuETYfyhHcCLT/4yZoH8KJu7jyK00JSIOvwf6v yN1Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:dkim-signature; bh=Qk1teTE+M+IujpCJ4fnOYjeYPWGwjvW8JXrxo/yH0Jc=; b=uRkKb/khKXH1jatoSxM34YLlTNyekljwF41adzS8/K6Rl6EeXRQIZ3j20bBf38IR10 x2Jv7VmtbM8Pb4nv6xRaqE1b6hGg6zP+aUD/PfDola4PFbCkfnjSuVRD8ZBEZJ1wKVkC /+EjfTrYQJQluC3IzDnGEpCnNAVQXkfdPJcVMQKFHTB+NDXJJvVEYiNRY/Tjh9Y4tsGy wGRN9FeFtkTUJetu/Vd/y7eDWlh3eajrx1PjwmZyrnN0Ncw+/FEDwFU4m2blTziwgFle MI8lGnkIXRPoE28Zkt3IWvohO2HYbAvLCWAQ4zCpv6+IbaT15pX57pEU8jHQMVrrHsjn CNuw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=bS38Kka2; spf=pass (google.com: domain of keescook@chromium.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id u17sor9735844pgm.43.2019.06.10.11.07.06 for (Google Transport Security); Mon, 10 Jun 2019 11:07:06 -0700 (PDT) Received-SPF: pass (google.com: domain of keescook@chromium.org designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=bS38Kka2; spf=pass (google.com: domain of keescook@chromium.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Qk1teTE+M+IujpCJ4fnOYjeYPWGwjvW8JXrxo/yH0Jc=; b=bS38Kka2lRnznRWhG8/qOGDxKjllgWQ6UMeG3F2amaGnqe8pK0xiGk3vZdBB3YxIb3 SWpAwEtE9q/WxIcVXvPngtzttAwOIVkoldUG9+Ng+5o+FvKdQZW1HjakB3VBQBFOd4GH 8QDt5M3wpL9e9LGdgrn8sofUH/zfBbAJ6Uge8= X-Google-Smtp-Source: APXvYqwpdKpmgyrcHoPqfm2kAKseftWNyRK4QJdbz1OaJAD6dgVCG3NHvWUoe0J25QMfVAkrE6hAGQ== X-Received: by 2002:a65:6104:: with SMTP id z4mr16749806pgu.319.1560190025622; Mon, 10 Jun 2019 11:07:05 -0700 (PDT) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id x7sm11154611pfm.82.2019.06.10.11.07.04 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 10 Jun 2019 11:07:04 -0700 (PDT) Date: Mon, 10 Jun 2019 11:07:03 -0700 From: Kees Cook To: Catalin Marinas Cc: Andrey Konovalov , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Leon Romanovsky , Luc Van Oostenryck , Dave Martin , Khalid Aziz , enh , Jason Gunthorpe , Christoph Hellwig , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Robin Murphy , Kevin Brodsky , Szabolcs Nagy Subject: Re: [PATCH v16 02/16] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Message-ID: <201906101106.3CA50745E3@keescook> References: <4327b260fb17c4776a1e3c844f388e4948cfb747.1559580831.git.andreyknvl@google.com> <20190610175326.GC25803@arrakis.emea.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190610175326.GC25803@arrakis.emea.arm.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jun 10, 2019 at 06:53:27PM +0100, Catalin Marinas wrote: > On Mon, Jun 03, 2019 at 06:55:04PM +0200, Andrey Konovalov wrote: > > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > > index e5d5f31c6d36..9164ecb5feca 100644 > > --- a/arch/arm64/include/asm/uaccess.h > > +++ b/arch/arm64/include/asm/uaccess.h > > @@ -94,7 +94,7 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si > > return ret; > > } > > > > -#define access_ok(addr, size) __range_ok(addr, size) > > +#define access_ok(addr, size) __range_ok(untagged_addr(addr), size) > > I'm going to propose an opt-in method here (RFC for now). We can't have > a check in untagged_addr() since this is already used throughout the > kernel for both user and kernel addresses (khwasan) but we can add one > in __range_ok(). The same prctl() option will be used for controlling > the precise/imprecise mode of MTE later on. We can use a TIF_ flag here > assuming that this will be called early on and any cloned thread will > inherit this. > > Anyway, it's easier to paste some diff than explain but Vincenzo can > fold them into his ABI patches that should really go together with > these. I added a couple of MTE definitions for prctl() as an example, > not used currently: > > ------------------8<--------------------------------------------- > diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h > index fcd0e691b1ea..2d4cb7e4edab 100644 > --- a/arch/arm64/include/asm/processor.h > +++ b/arch/arm64/include/asm/processor.h > @@ -307,6 +307,10 @@ extern void __init minsigstksz_setup(void); > /* PR_PAC_RESET_KEYS prctl */ > #define PAC_RESET_KEYS(tsk, arg) ptrauth_prctl_reset_keys(tsk, arg) > > +/* PR_UNTAGGED_UADDR prctl */ > +int untagged_uaddr_set_mode(unsigned long arg); > +#define SET_UNTAGGED_UADDR_MODE(arg) untagged_uaddr_set_mode(arg) > + > /* > * For CONFIG_GCC_PLUGIN_STACKLEAK > * > diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h > index c285d1ce7186..89ce77773c49 100644 > --- a/arch/arm64/include/asm/thread_info.h > +++ b/arch/arm64/include/asm/thread_info.h > @@ -101,6 +101,7 @@ void arch_release_task_struct(struct task_struct *tsk); > #define TIF_SVE 23 /* Scalable Vector Extension in use */ > #define TIF_SVE_VL_INHERIT 24 /* Inherit sve_vl_onexec across exec */ > #define TIF_SSBD 25 /* Wants SSB mitigation */ > +#define TIF_UNTAGGED_UADDR 26 > > #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) > #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) > @@ -116,6 +117,7 @@ void arch_release_task_struct(struct task_struct *tsk); > #define _TIF_FSCHECK (1 << TIF_FSCHECK) > #define _TIF_32BIT (1 << TIF_32BIT) > #define _TIF_SVE (1 << TIF_SVE) > +#define _TIF_UNTAGGED_UADDR (1 << TIF_UNTAGGED_UADDR) > > #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ > _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index 9164ecb5feca..54f5bbaebbc4 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -73,6 +73,9 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si > { > unsigned long ret, limit = current_thread_info()->addr_limit; > > + if (test_thread_flag(TIF_UNTAGGED_UADDR)) > + addr = untagged_addr(addr); > + > __chk_user_ptr(addr); > asm volatile( > // A + B <= C + 1 for all A,B,C, in four easy steps: > @@ -94,7 +97,7 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si > return ret; > } > > -#define access_ok(addr, size) __range_ok(untagged_addr(addr), size) > +#define access_ok(addr, size) __range_ok(addr, size) > #define user_addr_max get_fs > > #define _ASM_EXTABLE(from, to) \ > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 3767fb21a5b8..fd191c5b92aa 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -552,3 +552,18 @@ void arch_setup_new_exec(void) > > ptrauth_thread_init_user(current); > } > + > +/* > + * Enable the relaxed ABI allowing tagged user addresses into the kernel. > + */ > +int untagged_uaddr_set_mode(unsigned long arg) > +{ > + if (is_compat_task()) > + return -ENOTSUPP; > + if (arg) > + return -EINVAL; > + > + set_thread_flag(TIF_UNTAGGED_UADDR); > + > + return 0; > +} I think this should be paired with a flag clearing in copy_thread(), yes? (i.e. each binary needs to opt in) -- Kees Cook