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 9B919C43381 for ; Mon, 18 Mar 2019 17:19:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E05020863 for ; Mon, 18 Mar 2019 17:19:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eTZPglq7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727786AbfCRRTk (ORCPT ); Mon, 18 Mar 2019 13:19:40 -0400 Received: from mail-vs1-f73.google.com ([209.85.217.73]:42779 "EHLO mail-vs1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727735AbfCRRR4 (ORCPT ); Mon, 18 Mar 2019 13:17:56 -0400 Received: by mail-vs1-f73.google.com with SMTP id r185so3957407vsc.9 for ; Mon, 18 Mar 2019 10:17:55 -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=UykDW4hFaDHfzyUH5xSGMBQs4gGYEgUL/nC+SEDYWFU=; b=eTZPglq7PxVqxdqVAjoMC4HmmCrWD8Td2oOWhHZFu/cW19YPVAKsaJLDurjgd2ljVf XFoitnM7dNKXaO1X3w5n48lJ0Y+z6lMVYoHTi6MyqIKBKDduB9n8l/eQ3eoQ6ApOGJcf g0Ut1Mty7B6R+MM5DXRurd3w783o+tqjI10hk93IissEzK7cyNctMDjvmU3Tdk6WDEwH ffIMuMSLEoDbieTKF2ybjM0vJlmx+cWPNY/uy7bo6luMmancF6Vim1Jp4tv/8hL6d3pb M2HFyE+DxIM6V89Ha75sQlU/Ar8a05rWTSWi6zpfjkxsTGWw3NraARaPUHt9My5Uw9OY 7lHA== 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=UykDW4hFaDHfzyUH5xSGMBQs4gGYEgUL/nC+SEDYWFU=; b=D7iDF0EaugWRkC2u/eWNH+py6pSDCUT7c3//EArwGkSCBW+dR05lM7A+QzRQXKEdbc SloNYLG9NX1BuebSYBOuGRxsdyW927TY/1Ag4/F485HzcRNMSXL+pROzlUDjkM3kCkb7 4z6y7uDVOh0OKkuQ9m1uGFKaucsmoCtz6uhTNje5c6OqiXIVIqQE7fkWGyRZcfOajypC BlFJb3rAXBWK0ImHn/dEuZC+w0MyyKqu0PwpNYtc0m7GT4Z1/zTlHdaySFqMUA0E75zT Bm7xGUPyua+oBGnyJp/JiYgsLZ9VTP7kvukLX6JqoziVriiAKfApeL8i6foeXAd/xwof uKmQ== X-Gm-Message-State: APjAAAVPlANUg0r8m9rhA3KeRS2z0x8Sm86zckxh6PWDZlNsvzViIEi8 8AivfGwfv+RxYdeqdiij/uFQtmBTUkq6j0aS X-Google-Smtp-Source: APXvYqw1yRv1Lvlj4b/qzRYNiehInvLnccniboB47LbD/6n+0FpFdxyh/c9QXVRmnP7ZYupHxKhIzMKUChtQA6Na X-Received: by 2002:a1f:1e4a:: with SMTP id e71mr11807432vke.2.1552929475245; Mon, 18 Mar 2019 10:17:55 -0700 (PDT) Date: Mon, 18 Mar 2019 18:17:34 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.21.0.225.g810b269d1ac-goog Subject: [PATCH v12 02/13] 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: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@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(); -- 2.21.0.225.g810b269d1ac-goog