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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 3CC0AFA372C for ; Fri, 8 Nov 2019 12:37:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 117EE2245A for ; Fri, 8 Nov 2019 12:37:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573216641; bh=Ki9aEnDnL+qAauiZl1KpmDrg7BIFs2cclw7Id7tdNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZhxmMDs7jV+pRrjPRQ3URmEusxVUIlyxKnu8QxWMBprJCJ0neRPLbNz/EHHLpYdfG BkmBgXdPlM+xmtPfEekXt+OZw3ioY+h3bQBa347jyYlSTfYtgCJrNFV6NbPaiTeSRL Mz9FxvJ6FPzmxEqSDwarz0Z1rg4OhMpuoVTXdilM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727164AbfKHMhU (ORCPT ); Fri, 8 Nov 2019 07:37:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:44956 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726372AbfKHMhU (ORCPT ); Fri, 8 Nov 2019 07:37:20 -0500 Received: from localhost.localdomain (lfbn-mar-1-550-151.w90-118.abo.wanadoo.fr [90.118.131.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EC6A4224BD; Fri, 8 Nov 2019 12:37:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573216639; bh=Ki9aEnDnL+qAauiZl1KpmDrg7BIFs2cclw7Id7tdNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=la4Flkp4Io9K46Z18LFXB/z+SHy7g6hRH9REYL0DubetFcoHeajRV+ccz+J2wP4h0 0pqzEy4WRrhbXAMnYUvORUFYNlGTR6N9m2ZnX47pDX/G4fNCBi31C3fEktRukTmwxR WSFlb7jxykSo/zaVBDT/Qg95th3rQm5k46LDBY1A= From: Ard Biesheuvel To: stable@vger.kernel.org Cc: linus.walleij@linaro.org, rmk+kernel@armlinux.org.uk, Julien Thierry , Ard Biesheuvel Subject: [PATCH for-stable-4.4 42/50] ARM: 8796/1: spectre-v1,v1.1: provide helpers for address sanitization Date: Fri, 8 Nov 2019 13:35:46 +0100 Message-Id: <20191108123554.29004-43-ardb@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191108123554.29004-1-ardb@kernel.org> References: <20191108123554.29004-1-ardb@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Julien Thierry Commit afaf6838f4bc896a711180b702b388b8cfa638fc upstream. Introduce C and asm helpers to sanitize user address, taking the address range they target into account. Use asm helper for existing sanitization in __copy_from_user(). Signed-off-by: Julien Thierry Signed-off-by: Russell King Signed-off-by: David A. Long Reviewed-by: Julien Thierry Signed-off-by: Sasha Levin Signed-off-by: Ard Biesheuvel --- arch/arm/include/asm/assembler.h | 11 +++++++++ arch/arm/include/asm/uaccess.h | 26 ++++++++++++++++++++ arch/arm/lib/copy_from_user.S | 6 +---- 3 files changed, 38 insertions(+), 5 deletions(-) diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 483481c6937e..f2624fbd0336 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -461,6 +461,17 @@ THUMB( orr \reg , \reg , #PSR_T_BIT ) #endif .endm + .macro uaccess_mask_range_ptr, addr:req, size:req, limit:req, tmp:req +#ifdef CONFIG_CPU_SPECTRE + sub \tmp, \limit, #1 + subs \tmp, \tmp, \addr @ tmp = limit - 1 - addr + addhs \tmp, \tmp, #1 @ if (tmp >= 0) { + subhss \tmp, \tmp, \size @ tmp = limit - (addr + size) } + movlo \addr, #0 @ if (tmp < 0) addr = NULL + csdb +#endif + .endm + .macro uaccess_disable, tmp, isb=1 #ifdef CONFIG_CPU_SW_DOMAIN_PAN /* diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 98bbf89763a6..9ae610bf5234 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -137,6 +137,32 @@ static inline void set_fs(mm_segment_t fs) #define __inttype(x) \ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) +/* + * Sanitise a uaccess pointer such that it becomes NULL if addr+size + * is above the current addr_limit. + */ +#define uaccess_mask_range_ptr(ptr, size) \ + ((__typeof__(ptr))__uaccess_mask_range_ptr(ptr, size)) +static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr, + size_t size) +{ + void __user *safe_ptr = (void __user *)ptr; + unsigned long tmp; + + asm volatile( + " sub %1, %3, #1\n" + " subs %1, %1, %0\n" + " addhs %1, %1, #1\n" + " subhss %1, %1, %2\n" + " movlo %0, #0\n" + : "+r" (safe_ptr), "=&r" (tmp) + : "r" (size), "r" (current_thread_info()->addr_limit) + : "cc"); + + csdb(); + return safe_ptr; +} + /* * Single-value transfer routines. They automatically use the right * size if we just have the right pointer type. Note that the functions diff --git a/arch/arm/lib/copy_from_user.S b/arch/arm/lib/copy_from_user.S index d36329cefedc..e32b51838439 100644 --- a/arch/arm/lib/copy_from_user.S +++ b/arch/arm/lib/copy_from_user.S @@ -93,11 +93,7 @@ ENTRY(arm_copy_from_user) #ifdef CONFIG_CPU_SPECTRE get_thread_info r3 ldr r3, [r3, #TI_ADDR_LIMIT] - adds ip, r1, r2 @ ip=addr+size - sub r3, r3, #1 @ addr_limit - 1 - cmpcc ip, r3 @ if (addr+size > addr_limit - 1) - movcs r1, #0 @ addr = NULL - csdb + uaccess_mask_range_ptr r1, r2, r3, ip #endif #include "copy_template.S" -- 2.20.1