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=-16.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 7779EC31E46 for ; Wed, 12 Jun 2019 11:45:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 524642082C for ; Wed, 12 Jun 2019 11:45:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iMRCrqRs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728150AbfFLLnm (ORCPT ); Wed, 12 Jun 2019 07:43:42 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:56526 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730786AbfFLLnl (ORCPT ); Wed, 12 Jun 2019 07:43:41 -0400 Received: by mail-qt1-f201.google.com with SMTP id p43so8770215qtk.23 for ; Wed, 12 Jun 2019 04:43:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=pF1pY6g9sgHe6SSJdZReBxN/hHHz/1mBqQ4jLohhQOE=; b=iMRCrqRsfaLBvoWwOfr75mSJ/VPfvlbAFbDtrOANqSuL+z1aGCJpTI0vsQBJ49zvkV 9E9fBJ+sa0296EIJ5umEi+BHGLGKU1WldUfLsc5lzjtqovn6xo5wnnj4Lmb0O9PgfLXm rcwLyJjNEekU9EtCutlVconxtA95VHk5TlDWuAVOA+JWDgv52TV4yWWRYEX7ZgqRnURM Eul1F8JBswSLtsZ6lUMRapd1H2weXhkqX5JahODOopa1MhAlxblNV2Op319cxPCbAAUf 9L64VhEstL8JTyQhso+M/6lNjrHhHWa2qS+F7je7+fvMkiPQ8oGbPBPAqN2Cie9HgxaI uOrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=pF1pY6g9sgHe6SSJdZReBxN/hHHz/1mBqQ4jLohhQOE=; b=mxj36pNvRrpYXpYId9DWeZ/SskMVaFhnKHvTZ5xcDPOk4x4pR9vtBv9TFg5EAQ73C4 Qww2XBjLFlgx97qZErtgn3AAh7b8clpEV/mTWqQ4AE7+TToIRhjGavqaGfeN7XN26N48 y7AMdwDwtG1InqDKrgeert6KRViMvWEmb2mscpxV9cZfplqRS+sYfieajkMImNIjtUa8 cIPQIhSA+RX6LPVCbuyLCUkqF0WEV7Z4al0323/icpAD6X3dXidYNd0Wp3Z5SOADfmD7 rE+j9zmyj3AGBLHmw1XT9DDxLog5NsLKZ2Pxy/mnICKHDruEewuiIfFu992awO9c72Yt LSIg== X-Gm-Message-State: APjAAAXMlgJRTlDQtJRQSoar96D2O/nhux5n+gg7uvP1T2zixNXbDtTu 3YAODUDNmklFcHUBEkHesxTvW/s7TIffYDmV X-Google-Smtp-Source: APXvYqwDKTUvtDmA6SMmQkKz65W969SZufp61k02G9fCL+2/fp67qf94d2M1YkNH+hXtOrCQMRSpsi3TuTa5t/Fk X-Received: by 2002:a37:6b42:: with SMTP id g63mr50597391qkc.80.1560339819968; Wed, 12 Jun 2019 04:43:39 -0700 (PDT) Date: Wed, 12 Jun 2019 13:43:18 +0200 In-Reply-To: Message-Id: <9ed583c1a3acf014987e3aef12249506c1c69146.1560339705.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.22.0.rc2.383.gf4fbbf30c2-goog Subject: [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr From: Andrey Konovalov To: 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 , Vincenzo Frascino , 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 , Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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. copy_from_user (and a few other similar functions) are used to copy data from user memory into the kernel memory or vice versa. Since a user can provided a tagged pointer to one of the syscalls that use copy_from_user, we need to correctly handle such pointers. Do this by untagging user pointers in access_ok and in __uaccess_mask_ptr, before performing access validity checks. Note, that this patch only temporarily untags the pointers to perform the checks, but then passes them as is into the kernel internals. Reviewed-by: Kees Cook Reviewed-by: Catalin Marinas Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/uaccess.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index e5d5f31c6d36..df729afca0ba 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -73,6 +73,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si { unsigned long ret, limit = current_thread_info()->addr_limit; + addr = untagged_addr(addr); + __chk_user_ptr(addr); asm volatile( // A + B <= C + 1 for all A,B,C, in four easy steps: @@ -226,7 +228,8 @@ static inline void uaccess_enable_not_uao(void) /* * Sanitise a uaccess pointer such that it becomes NULL if above the - * current addr_limit. + * current addr_limit. In case the pointer is tagged (has the top byte set), + * untag the pointer before checking. */ #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr) static inline void __user *__uaccess_mask_ptr(const void __user *ptr) @@ -234,10 +237,11 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) void __user *safe_ptr; asm volatile( - " bics xzr, %1, %2\n" + " bics xzr, %3, %2\n" " csel %0, %1, xzr, eq\n" : "=&r" (safe_ptr) - : "r" (ptr), "r" (current_thread_info()->addr_limit) + : "r" (ptr), "r" (current_thread_info()->addr_limit), + "r" (untagged_addr(ptr)) : "cc"); csdb(); -- 2.22.0.rc2.383.gf4fbbf30c2-goog