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 D294BC43219 for ; Tue, 30 Apr 2019 13:25:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A266C21743 for ; Tue, 30 Apr 2019 13:25:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cjAZo1be" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727885AbfD3NZ3 (ORCPT ); Tue, 30 Apr 2019 09:25:29 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:32905 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728098AbfD3NZ2 (ORCPT ); Tue, 30 Apr 2019 09:25:28 -0400 Received: by mail-pf1-f202.google.com with SMTP id i23so9103533pfa.0 for ; Tue, 30 Apr 2019 06:25:27 -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=iMX/B5fmWIyVD7HiJ4Wv4o+j/sepsQrZu53mZ3fneJ54NlL0XKraRfKLsu5A5lxy8p U2nVdL3ofwBvpNYrc0aocG0dVizi9KxARdHBG1C5Jnwpj9uZ6ERm8QHX/hLUP2C0k5vX akwzIbPArvs7rP22nMrvVv4zHljGTfolKRqEHDliG8Ro1MMTDzIZcVG+I6slV2CSvztm plP0jitxOMtg5F1zZz97wImdd72Jl4SoPgaazDr70ikc+VUmZinz6xsYWrKSz6GU1Z0D QS5Da+UicwEsDLNa50CHyQLDRmJ+H+e78Hyl69UYVQNabHO0VYBTpdfECL7pKRXBe8Qf xaMQ== X-Gm-Message-State: APjAAAUUqVW7eDhNjDH/DEpkES9VM1PTVVI/xPxslX6Grpi+8vNp1str 7l0zft5AfTN4yR6tw9ForPT/o5mp3yCrU4gV 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 Content-Type: text/plain; charset="UTF-8" Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@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(); -- 2.21.0.593.g511ec345e18-goog