From patchwork Tue Apr 30 13:24:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10923635 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 A4DA6933 for ; Tue, 30 Apr 2019 13:28:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 956F428AE7 for ; Tue, 30 Apr 2019 13:28:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8931828AF7; Tue, 30 Apr 2019 13:28:10 +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 1D76728AE7 for ; Tue, 30 Apr 2019 13:28:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727904AbfD3NZY (ORCPT ); Tue, 30 Apr 2019 09:25:24 -0400 Received: from mail-pg1-f202.google.com ([209.85.215.202]:43438 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727856AbfD3NZY (ORCPT ); Tue, 30 Apr 2019 09:25:24 -0400 Received: by mail-pg1-f202.google.com with SMTP id x13so5199418pgl.10 for ; Tue, 30 Apr 2019 06:25:24 -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=IkuD9zPPDPrNqKOg+1EuZo5HlTMskU88lY/hO73XGBQ=; b=cjAZo1bevEgDG9f0Gp0lCqBUDVGf7WH9HfahHvPYK3yXKOMpkTJl6c0Qs/+BaViS4F SVbEHv0pbmF0M0fXn45Xz+XZ5NA51A6Q84gce81tqYq+4vQ4fSd4Vfr74XM9VMTqpEUn hpbIVHi0Y6E4lGzikQQHuG5LSWrNkshsuGLGjPRywGWJWT4PFmQUF2llhQi6ncC/Vlfh XyXZ2xzPVmh+mASSDoCOMBPHpUNh2v+x16jbihEdr4DI6v1V/jUL7ilAE/v54hqYIVN8 AFB4b6bLnE3ptsM0NTOpxh1giv5Af/8Vei/jZ/b9XgJhABJa8DnBXyZnippbFF98erxD 64TA== 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=IkuD9zPPDPrNqKOg+1EuZo5HlTMskU88lY/hO73XGBQ=; b=V7B1qomrXTfaMrSJBQi/QY9wuW2DVdNmSEC1WwXhjUxNkA33ph34CUt3EczTG1FMza 2e+/fz5fo096vBhdXsT2UO7pJBj1whSxA+pTOZOLCi6sxD7lYF0nNuLTlEa4l4BPwasr 3sQ1+AtkLjBum9Omg4azr0sHr1Rv9RqvZk03ga01Sou+alm8jfYaHCTcxdVXJ54G+G7g sOa0Bo95ihSeE7aPm51TOcpgIZkS/AX4LemiTdRZUUjF8c20AKlxal6HyihXxji+iz39 5m+Ao2w9ueGoLWzLsp7w13HzH3kdIYT3SQZJKEY9H3R4sCTIQxjSdGs2V/1fbfhgAn7b DrqQ== X-Gm-Message-State: APjAAAVc5y9T8pHgS8xoKaKViEQ0Su+4Njm4E5C8nC5qN7Zi5ho93wMN F6m1KP4v4qcgMTD9NESikjPLzH8npKrczb7m X-Google-Smtp-Source: APXvYqxwzeO4aaEq5t7dlXsyLEMZLxNA1xUAM/PWlhFhSshLHzTvKlXrQBr9Il+4R5AJQuOw/QR46XMvR3q8fhhC X-Received: by 2002:a65:534b:: with SMTP id w11mr7522791pgr.210.1556630723459; Tue, 30 Apr 2019 06:25:23 -0700 (PDT) Date: Tue, 30 Apr 2019 15:24:58 +0200 In-Reply-To: Message-Id: <29b7234f48a282037bdfc23e07ff167756fca0df.1556630205.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.21.0.593.g511ec345e18-goog Subject: [PATCH v14 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 , Kuehling@google.com, Felix , Deucher@google.com, Alexander , Koenig@google.com, Christian , 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 , Chintan Pandya , Luc Van Oostenryck , Dave Martin , 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 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();