From patchwork Mon May 6 16:30:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10931381 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5F8AC1575 for ; Mon, 6 May 2019 16:31:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4DD44287EA for ; Mon, 6 May 2019 16:31:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 418EB2884B; Mon, 6 May 2019 16:31:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A0292287EA for ; Mon, 6 May 2019 16:31:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726709AbfEFQbO (ORCPT ); Mon, 6 May 2019 12:31:14 -0400 Received: from mail-ot1-f74.google.com ([209.85.210.74]:53018 "EHLO mail-ot1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726679AbfEFQbO (ORCPT ); Mon, 6 May 2019 12:31:14 -0400 Received: by mail-ot1-f74.google.com with SMTP id h26so7754247otm.19 for ; Mon, 06 May 2019 09:31:13 -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=/Xcm/dv07E6tB6Fg+Bd1uLrNx0q2WagwUZqys5y8XCQ=; b=rAOt6QkMD/QKlKVog82fKw84EsQnaASzO/nI8W5EIDbrmmjV3gr6+15mZ10SMb6Rf5 i/ZniLNvWV//CPRfADxSnSKtN/6Gg017m4Gik6Cenllh7RN6CfI/AKj72maW2yKQfmpN GrE1GcO1EKZaX0U+I3FWYiw4misL8V2knxuMTZnhd7+ifYq/drNNa4087ayYcqsu4RzV YnDg0sSjmZfX/PgQJ/vdVYIZT3u95MTKmAQy8Dfp2UhL6OXfBsqkSnVsPRCgY0ZcNTeM d3f8I7eWT+VKLfqWWZufhZUUDge/eC39ycIbKQ1fqVyQEg05Z5H0MBzHuW0wC/j81BOZ a7SA== 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=/Xcm/dv07E6tB6Fg+Bd1uLrNx0q2WagwUZqys5y8XCQ=; b=dQ+Adgjj5UIFhro8bDFVjLkPbmV8OQw1q/eFaog7tar5f8N3yw3roifqB52VZkWJOI 26LGjYfFNKaXAreF4GZWnA30+KSDGZkk1GTWcOJuGZQrUYrHYi+314+V6ii7OIF++yTM rIZMoOrodYvKcjg7rZL1NVZXrm4PCeSDqmwg4QcHGNl7Hu1+S/54NuxU5yVZoXHKwiya Q7gcKrQj9hpNk4pONrrrLeA6DYSuZWqZb4QDOI/3Ug/h1k3dItaUvVVew2ePPTZcsBV3 1MRMzVF2Bc305U2HHt0+lvqOISnXHQZkayuIQ6UY3rJKNr1RHwkymBUYzpUMkYqy2etz 4R4w== X-Gm-Message-State: APjAAAVa6AUEWJaL74Y18nzET9n/suY3EhnBitDkuEOV+bYe80ppsHBu Kltt0wmAMHWL7AGV27OMPXriHGkDQt5DslcT X-Google-Smtp-Source: APXvYqwsU29/a5rUuddp5tcfbPS3CQhzs1NWwE9FVJC7oUUpeYui7bu7Qsrr1jpZGFt27bCra6fHy1EBLcG5J9Rk X-Received: by 2002:a9d:4917:: with SMTP id e23mr17423724otf.63.1557160273461; Mon, 06 May 2019 09:31:13 -0700 (PDT) Date: Mon, 6 May 2019 18:30:48 +0200 In-Reply-To: Message-Id: <02e1242715cc1bf23a139e5e8152fb4feaa4b41d.1557160186.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a-goog Subject: [PATCH v15 02/17] 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 , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Robin Murphy , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy , Andrey Konovalov Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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();