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=-16.4 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_HELO_NONE,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 68AFAC43613 for ; Mon, 24 Jun 2019 14:33:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 309E121537 for ; Mon, 24 Jun 2019 14:33:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="daRRCGEX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728864AbfFXOdK (ORCPT ); Mon, 24 Jun 2019 10:33:10 -0400 Received: from mail-vk1-f201.google.com ([209.85.221.201]:55539 "EHLO mail-vk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727888AbfFXOdI (ORCPT ); Mon, 24 Jun 2019 10:33:08 -0400 Received: by mail-vk1-f201.google.com with SMTP id b85so6430943vke.22 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=Ca0zR7iYUZSNmZnbHaqyK5rdrS0k0acCljPwlO/dXqsUlWtQbvsC2jMi6cP7mlYAKS 4dMK2nBymCzescuHLkSgbxIVGaXZavV/DMCB4LIxk/nQYkPBf6Aa1q+1SKmU389oc243 WhVxBJ0JBJG+loc3Vl1YzwFGSI6jk/i/wPBSgJadn62nbm6cBG4NywwfimQJSBv40D8v GdUdVfkz/FvdqQws4Nry/MhrKVAv+KiDLDqubM/+5hfyij+x5EBpUpT+TVv/jVxWoqFX F2chVEZr6bmEe3AWonTOTH3IAwnOnh0vfeSSUeKsKznjuIYIxHIZPXV10pBN/ITo0lDp n/Ag== X-Gm-Message-State: APjAAAUvouGXDdICBeZ8dUaVPUQZS4QnwEWfUKgUNP1gVawzzh9GIo0b FrvofdaEZKJTazlPfVsjEmfNpXQL9mS2Dedh 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 Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(); -- 2.22.0.410.gd8fdbe21b5-goog