From patchwork Mon Mar 18 17:17:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 1057969 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="eTZPglq7"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44NNGH5XVkz9s6w for ; Tue, 19 Mar 2019 04:19:35 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727375AbfCRRTd (ORCPT ); Mon, 18 Mar 2019 13:19:33 -0400 Received: from mail-vk1-f202.google.com ([209.85.221.202]:34856 "EHLO mail-vk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727736AbfCRRR5 (ORCPT ); Mon, 18 Mar 2019 13:17:57 -0400 Received: by mail-vk1-f202.google.com with SMTP id z75so7757380vkd.2 for ; Mon, 18 Mar 2019 10:17:55 -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=UykDW4hFaDHfzyUH5xSGMBQs4gGYEgUL/nC+SEDYWFU=; b=eTZPglq7PxVqxdqVAjoMC4HmmCrWD8Td2oOWhHZFu/cW19YPVAKsaJLDurjgd2ljVf XFoitnM7dNKXaO1X3w5n48lJ0Y+z6lMVYoHTi6MyqIKBKDduB9n8l/eQ3eoQ6ApOGJcf g0Ut1Mty7B6R+MM5DXRurd3w783o+tqjI10hk93IissEzK7cyNctMDjvmU3Tdk6WDEwH ffIMuMSLEoDbieTKF2ybjM0vJlmx+cWPNY/uy7bo6luMmancF6Vim1Jp4tv/8hL6d3pb M2HFyE+DxIM6V89Ha75sQlU/Ar8a05rWTSWi6zpfjkxsTGWw3NraARaPUHt9My5Uw9OY 7lHA== 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=UykDW4hFaDHfzyUH5xSGMBQs4gGYEgUL/nC+SEDYWFU=; b=NxPwzIydGvCxCxE2bJkTBo3VCGaZAZcze9FzoOCBjlHoYg9ThP5Hu7llOs6VR/EFGS hNHDSCvWLddYKLh6LxfmfkDTHUHCDC8xIlUjtidrmvS1OI3sOkhkUqM0sCK2rPbysiZm 7+XKB3RDAkqGclFbkm5Yw06r3JC2T4P1OMm2IBJRVryz9u5REt0mWCJjojVzuTDMcKoN fV47BStF447hhbw5SWbgjqobqyTVL1FWeL6xRNPLfy5ibXf/wXGBPEgQkK60zxRgGoal 4h/X/TqwVtwKNoEAikyXyOIT9tLEwmgNlYUR1P+LSFpwSA7ppSkxK+/sUGYj9wPQTHWD RWnQ== X-Gm-Message-State: APjAAAUY//ZcmEvz1DpB5yrjKVcvDdX3Y1PFkndxAFP84YYmuxG8WClS ywl0FMS6wxK5ALlGmMutX7YPwM6YptluSVHe X-Google-Smtp-Source: APXvYqw1yRv1Lvlj4b/qzRYNiehInvLnccniboB47LbD/6n+0FpFdxyh/c9QXVRmnP7ZYupHxKhIzMKUChtQA6Na X-Received: by 2002:a1f:1e4a:: with SMTP id e71mr11807432vke.2.1552929475245; Mon, 18 Mar 2019 10:17:55 -0700 (PDT) Date: Mon, 18 Mar 2019 18:17:34 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.21.0.225.g810b269d1ac-goog Subject: [PATCH v12 02/13] arm64: untag user pointers in access_ok and __uaccess_mask_ptr From: Andrey Konovalov To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy , Andrey Konovalov Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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();