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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 50179C31E46 for ; Wed, 12 Jun 2019 14:40:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2659220679 for ; Wed, 12 Jun 2019 14:40:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437786AbfFLOkX (ORCPT ); Wed, 12 Jun 2019 10:40:23 -0400 Received: from foss.arm.com ([217.140.110.172]:54772 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727626AbfFLOkX (ORCPT ); Wed, 12 Jun 2019 10:40:23 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 373762B; Wed, 12 Jun 2019 07:40:22 -0700 (PDT) Received: from [10.1.196.72] (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9DE913F557; Wed, 12 Jun 2019 07:40:17 -0700 (PDT) Subject: Re: [PATCH v17 08/15] userfaultfd, arm64: untag user pointers To: 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 Cc: Catalin Marinas , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Kees Cook , 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 References: From: Vincenzo Frascino Message-ID: <48893efc-039a-f7e8-19f0-1bd7b188b2c1@arm.com> Date: Wed, 12 Jun 2019 15:40:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 12/06/2019 12:43, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > userfaultfd code use provided user pointers for vma lookups, which can > only by done with untagged pointers. > > Untag user pointers in validate_range(). > > Reviewed-by: Catalin Marinas > Reviewed-by: Kees Cook > Signed-off-by: Andrey Konovalov Reviewed-by: Vincenzo Frascino > --- > fs/userfaultfd.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > index 3b30301c90ec..24d68c3b5ee2 100644 > --- a/fs/userfaultfd.c > +++ b/fs/userfaultfd.c > @@ -1263,21 +1263,23 @@ static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx, > } > > static __always_inline int validate_range(struct mm_struct *mm, > - __u64 start, __u64 len) > + __u64 *start, __u64 len) > { > __u64 task_size = mm->task_size; > > - if (start & ~PAGE_MASK) > + *start = untagged_addr(*start); > + > + if (*start & ~PAGE_MASK) > return -EINVAL; > if (len & ~PAGE_MASK) > return -EINVAL; > if (!len) > return -EINVAL; > - if (start < mmap_min_addr) > + if (*start < mmap_min_addr) > return -EINVAL; > - if (start >= task_size) > + if (*start >= task_size) > return -EINVAL; > - if (len > task_size - start) > + if (len > task_size - *start) > return -EINVAL; > return 0; > } > @@ -1327,7 +1329,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, > goto out; > } > > - ret = validate_range(mm, uffdio_register.range.start, > + ret = validate_range(mm, &uffdio_register.range.start, > uffdio_register.range.len); > if (ret) > goto out; > @@ -1516,7 +1518,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, > if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) > goto out; > > - ret = validate_range(mm, uffdio_unregister.start, > + ret = validate_range(mm, &uffdio_unregister.start, > uffdio_unregister.len); > if (ret) > goto out; > @@ -1667,7 +1669,7 @@ static int userfaultfd_wake(struct userfaultfd_ctx *ctx, > if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake))) > goto out; > > - ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len); > + ret = validate_range(ctx->mm, &uffdio_wake.start, uffdio_wake.len); > if (ret) > goto out; > > @@ -1707,7 +1709,7 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx, > sizeof(uffdio_copy)-sizeof(__s64))) > goto out; > > - ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len); > + ret = validate_range(ctx->mm, &uffdio_copy.dst, uffdio_copy.len); > if (ret) > goto out; > /* > @@ -1763,7 +1765,7 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, > sizeof(uffdio_zeropage)-sizeof(__s64))) > goto out; > > - ret = validate_range(ctx->mm, uffdio_zeropage.range.start, > + ret = validate_range(ctx->mm, &uffdio_zeropage.range.start, > uffdio_zeropage.range.len); > if (ret) > goto out; > -- Regards, Vincenzo