From patchwork Mon Jun 24 14:32:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11013487 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 EE564186E for ; Mon, 24 Jun 2019 14:35:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DED5928751 for ; Mon, 24 Jun 2019 14:35:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D24AD28C04; Mon, 24 Jun 2019 14:35:05 +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 654C028751 for ; Mon, 24 Jun 2019 14:35:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728413AbfFXOdK (ORCPT ); Mon, 24 Jun 2019 10:33:10 -0400 Received: from mail-vk1-f201.google.com ([209.85.221.201]:49925 "EHLO mail-vk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728078AbfFXOdI (ORCPT ); Mon, 24 Jun 2019 10:33:08 -0400 Received: by mail-vk1-f201.google.com with SMTP id o202so6445694vko.16 for ; Mon, 24 Jun 2019 07:33:08 -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=OFC24w2VYFjptSxPqCpbBEqhaUlc2rZ4vtg/DxWHKUY=; b=daRRCGEXfLHGLUQo//HRDLfqaBO4lfL42FrfPGRnRKOhn1XL6qGzvLE8amzWfXer5a WhALrZBTuSnnuN10/CaZpZqQ5oMU4MQefeNJm/AP0b4uEXgK32RunU93durvNp8XKKHL uQfK0a3nA5oC/DUYeVxUqLVQFd9uJpb2OtV7FV9mAWqDzJacQiBSNlyVGMSQHbzkOff3 MC+xIW6PfIq1tVQloxoUTZ3GncOdewoLB+fLV/jb+kaJgM+7s5iRXhY273LkR2goOH7a Ap1pVnJAk4onxG8CZjucr85/ku+lb+LecGyuZhueMHSpk8X8CCgAIxuGrhQgzxcP8FnL C2Sw== 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=OFC24w2VYFjptSxPqCpbBEqhaUlc2rZ4vtg/DxWHKUY=; b=ojsVp+DsZItQIHYlPc7SW6qZhYZfouHmXbdtQyx6Ng4sPv4uyV7UGatQSMIzIwtTWQ Uea76SlXwkiW8lIcCK+PMYScPI/n+15QDtqKzSJh/PWfdAY+Yot1Eb0v9RyhsLZ2/MiY 182W70226pN0nv4j/kwgRBuwBVJrskKa2i3hfqW5el1C/C70DKuxj7nJ+44zK8LRdaaW s3pKKZnhlB91UFIqfJUFEwMfho+H0ZKbhqbJdUoSlvTkZlEKAh9Qmbcjxei5eeaiDJ5h XvIr23zPN6gGXr9xguHC9oVDx6sxZ+XQ3PMdvBbgaqFJuzgwcUaJ2sPcSUfzoNZGNriK XCqA== X-Gm-Message-State: APjAAAXXHPHeAtTu/SG9qJXvvu9XUqb1R37R8oa/N+6lmPqxc5zM1fkH R1GwuJ7r184C7u6Vjq1q+oIhRQ50HCThtrsc X-Google-Smtp-Source: APXvYqztHTWRHYOC83H4IfNbENBsJMJpCmuVpe91PkFE56CWhu5KbIzw0hmUvviWu8/4yX8wEpc7iI+Lm7IC+LHT X-Received: by 2002:a67:6e44:: with SMTP id j65mr66559877vsc.132.1561386787480; Mon, 24 Jun 2019 07:33:07 -0700 (PDT) Date: Mon, 24 Jun 2019 16:32:46 +0200 In-Reply-To: Message-Id: <98cbd89549395d372a4a20ab2ac536bf19d37e52.1561386715.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v18 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 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch is a part of a series that extends 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: Vincenzo Frascino 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 5a1c32260c1f..a138e3b4f717 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -62,6 +62,8 @@ 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: @@ -215,7 +217,8 @@ 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) @@ -223,10 +226,11 @@ 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();