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=-16.6 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_PASS,URIBL_BLOCKED,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 84F95C10F0B for ; Fri, 15 Mar 2019 19:54:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 54202218D8 for ; Fri, 15 Mar 2019 19:54:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bMyL6O7m" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726676AbfCOTyA (ORCPT ); Fri, 15 Mar 2019 15:54:00 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:33091 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727262AbfCOTvv (ORCPT ); Fri, 15 Mar 2019 15:51:51 -0400 Received: by mail-pf1-f202.google.com with SMTP id x23so11481000pfm.0 for ; Fri, 15 Mar 2019 12:51:50 -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=HBqdcrrZbnaUQvnw2SuV9xpSHs4pKIOHqIC9BZ3VFKg=; b=bMyL6O7mL3v0PpvhcraOwU0+T0KPIFPV/p7nmVTvmipE51X/RVpxp6XgCeUgtieP7G ixioELJzjz0dEoQWCYr0YK3/FbXsJYHqdPSXpUIsBdn1yDDXj6QnCZ35FOYA8i9HT63C 4NxOaja1Vj1CohRqNK5BDjm+Ej2ZsDeLIYnjGIPj/aDrjQ9HbzCW01i4AWSy9c6BCqBH VOneIHkae9V1wBY19FpITt5gyzE2kQ3GzB4IuuJ9g8/ByewueOS2EyupEZ9Fn2xI7TMs eSLl2rv00PucX+Qh3Q1GWwU/1iBbczPrTond0HrvoOUHVc5VY5X1umF2QYAhZzj9B3zd L8hA== 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=HBqdcrrZbnaUQvnw2SuV9xpSHs4pKIOHqIC9BZ3VFKg=; b=nh9sO2Ub8uDZ2yo+nUkgAqpP39kVEJ18ddVo9rEQPG5Wja7pPWkGS0cD4AalsJRaEY 77wAh6ntFtWejf80XYrA8c4pOTnhyKLsv6TFkysGxygcu8npl9ANmZVAIwTwlOPmiuc9 OpM6CkvmGpO8WXK/Cl6JCw4RqK7+qTz+r43FyExoK35SY/71j7HYDwUlOldexSxJGyOp z5rWnj2vl4+lTOFEreWdKAI9TGjJwYjrQV1hWxHhbCrqGjrtDP7znDc8qpabKiI9eCHq UNMVvcbZb2JpZ7c9v6SeNylk79pF86ekRWAwaDvfIAVjysvmU6TjoBluohcSHRDyAx9o 4Kyg== X-Gm-Message-State: APjAAAXkL809TrnuND7vLwMuE1D3sPNdIACG2/NsGAqeGtZLaSPzkj9l dY38wRLJyevgrk6bPIMHu5JSna5SIkjsVjxY X-Google-Smtp-Source: APXvYqwlT5i1jX7khcwaLfGY9H0rl+oWt5KckuYgCZmSJDPuy2OzcL+WBdRis5ZekWALtZsnFbHnM5bpC2RyyAOF X-Received: by 2002:a65:52c5:: with SMTP id z5mr2165417pgp.71.1552679510299; Fri, 15 Mar 2019 12:51:50 -0700 (PDT) Date: Fri, 15 Mar 2019 20:51:26 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.21.0.360.g471c308f928-goog Subject: [PATCH v11 02/14] arm64: untag user pointers in access_ok and __uaccess_mask_ptr From: Andrey Konovalov To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy , Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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: Catalin Marinas Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/uaccess.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) 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) #define user_addr_max get_fs #define _ASM_EXTABLE(from, to) \ @@ -226,7 +226,8 @@ 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 +235,11 @@ 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(); -- 2.21.0.360.g471c308f928-goog