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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 C22FDC3276D for ; Thu, 2 Jan 2020 22:16:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9269A22B48 for ; Thu, 2 Jan 2020 22:16:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578003384; bh=P9zYL2IjlJKQhbkr4O2SVoC2nzZza+pLAq77UjV2kn0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ImMe1Zdol9uwuetDFcufgWLRfFBwgyoWsT4FUZf0RKEdWQ8wNEnMhEZgcyAD4uqO5 BpS4y93bXKy1Og+csLMkgRltFsAW5HGc3rBxXPf+vkC1fYWfj9OYtwoEeRZ8iUMXpI zrHHwVUxOCcGtlFUYC3bhBncgbUh7tAiluinaBaQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728237AbgABWQX (ORCPT ); Thu, 2 Jan 2020 17:16:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:58172 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728231AbgABWQV (ORCPT ); Thu, 2 Jan 2020 17:16:21 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AE8ED21582; Thu, 2 Jan 2020 22:16:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578003380; bh=P9zYL2IjlJKQhbkr4O2SVoC2nzZza+pLAq77UjV2kn0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dm5vCe0nA05XBME4DOcLVOHwxB1aaJLKG6SZ3VPQlWMLVa9255wLbQFjJe/+JtK1Z ilRZiIngD0wYE3e+JeF8VohF1YEhILSjfB8BeLf8n0GUqIqYszrJYatnTqFZmQP7ga H5JuZ5bceoSYlih/6LZWNeLFFqUbUx9V/+Ba6NQo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+f25ecf4b2982d8c7a640@syzkaller-ppc64.appspotmail.com, Daniel Axtens , Michael Ellerman , Andrew Donnellan Subject: [PATCH 5.4 136/191] powerpc: Fix __clear_user() with KUAP enabled Date: Thu, 2 Jan 2020 23:06:58 +0100 Message-Id: <20200102215844.202313478@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102215829.911231638@linuxfoundation.org> References: <20200102215829.911231638@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrew Donnellan commit 61e3acd8c693a14fc69b824cb5b08d02cb90a6e7 upstream. The KUAP implementation adds calls in clear_user() to enable and disable access to userspace memory. However, it doesn't add these to __clear_user(), which is used in the ptrace regset code. As there's only one direct user of __clear_user() (the regset code), and the time taken to set the AMR for KUAP purposes is going to dominate the cost of a quick access_ok(), there's not much point having a separate path. Rename __clear_user() to __arch_clear_user(), and make __clear_user() just call clear_user(). Reported-by: syzbot+f25ecf4b2982d8c7a640@syzkaller-ppc64.appspotmail.com Reported-by: Daniel Axtens Suggested-by: Michael Ellerman Fixes: de78a9c42a79 ("powerpc: Add a framework for Kernel Userspace Access Protection") Signed-off-by: Andrew Donnellan [mpe: Use __arch_clear_user() for the asm version like arm64 & nds32] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191209132221.15328-1-ajd@linux.ibm.com Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/include/asm/uaccess.h | 9 +++++++-- arch/powerpc/lib/string_32.S | 4 ++-- arch/powerpc/lib/string_64.S | 6 +++--- 3 files changed, 12 insertions(+), 7 deletions(-) --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -401,7 +401,7 @@ copy_to_user_mcsafe(void __user *to, con return n; } -extern unsigned long __clear_user(void __user *addr, unsigned long size); +unsigned long __arch_clear_user(void __user *addr, unsigned long size); static inline unsigned long clear_user(void __user *addr, unsigned long size) { @@ -409,12 +409,17 @@ static inline unsigned long clear_user(v might_fault(); if (likely(access_ok(addr, size))) { allow_write_to_user(addr, size); - ret = __clear_user(addr, size); + ret = __arch_clear_user(addr, size); prevent_write_to_user(addr, size); } return ret; } +static inline unsigned long __clear_user(void __user *addr, unsigned long size) +{ + return clear_user(addr, size); +} + extern long strncpy_from_user(char *dst, const char __user *src, long count); extern __must_check long strnlen_user(const char __user *str, long n); --- a/arch/powerpc/lib/string_32.S +++ b/arch/powerpc/lib/string_32.S @@ -17,7 +17,7 @@ CACHELINE_BYTES = L1_CACHE_BYTES LG_CACHELINE_BYTES = L1_CACHE_SHIFT CACHELINE_MASK = (L1_CACHE_BYTES-1) -_GLOBAL(__clear_user) +_GLOBAL(__arch_clear_user) /* * Use dcbz on the complete cache lines in the destination * to set them to zero. This requires that the destination @@ -87,4 +87,4 @@ _GLOBAL(__clear_user) EX_TABLE(8b, 91b) EX_TABLE(9b, 91b) -EXPORT_SYMBOL(__clear_user) +EXPORT_SYMBOL(__arch_clear_user) --- a/arch/powerpc/lib/string_64.S +++ b/arch/powerpc/lib/string_64.S @@ -17,7 +17,7 @@ PPC64_CACHES: .section ".text" /** - * __clear_user: - Zero a block of memory in user space, with less checking. + * __arch_clear_user: - Zero a block of memory in user space, with less checking. * @to: Destination address, in user space. * @n: Number of bytes to zero. * @@ -58,7 +58,7 @@ err3; stb r0,0(r3) mr r3,r4 blr -_GLOBAL_TOC(__clear_user) +_GLOBAL_TOC(__arch_clear_user) cmpdi r4,32 neg r6,r3 li r0,0 @@ -181,4 +181,4 @@ err1; dcbz 0,r3 cmpdi r4,32 blt .Lshort_clear b .Lmedium_clear -EXPORT_SYMBOL(__clear_user) +EXPORT_SYMBOL(__arch_clear_user)