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,URIBL_BLOCKED,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 7FBA9C32750 for ; Fri, 2 Aug 2019 09:45:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59F6821726 for ; Fri, 2 Aug 2019 09:45:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739155; bh=oZQ86BBsGwGXKISr8ot9saUVaLRJbr10trhIT/B/b3Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=iWE4SrmcNLWSDkQZDgRmN548mkFIog4DVru4YU7kj/KjiLBSIlycaQKu96bjwEWYT uQHK47sVukI3SS40AXiCMRePuSkUkV9x3qmT8ytTOLmj/IVYa0n9yKt2oMGUL4ucJI sYss5jL3Er3cXRvPDUR9dvB/tm1ZshmaOl+r/Gcw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392033AbfHBJpy (ORCPT ); Fri, 2 Aug 2019 05:45:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:49726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392018AbfHBJpu (ORCPT ); Fri, 2 Aug 2019 05:45:50 -0400 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 5534020B7C; Fri, 2 Aug 2019 09:45:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739149; bh=oZQ86BBsGwGXKISr8ot9saUVaLRJbr10trhIT/B/b3Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aSArMo2UbjaRUZSe/9hUPXdT3tsqhsdVb1GU083CfKS+lfxid94tDz2feYNU0c398 JwuB9VmhDBKc/+H4AapKILOmf+kQmHUIjsgRku810o7du40fcsnT6CZ2BCbT9xsZPg 5icrKkRq/Cy5uXlpazh8+sYdvSJDFT2kgFkvxBc8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jeroen Roovers , Rolf Eike Beer , Helge Deller Subject: [PATCH 4.9 117/223] parisc: Fix kernel panic due invalid values in IAOQ0 or IAOQ1 Date: Fri, 2 Aug 2019 11:35:42 +0200 Message-Id: <20190802092246.763018856@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@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: Helge Deller commit 10835c854685393a921b68f529bf740fa7c9984d upstream. On parisc the privilege level of a process is stored in the lowest two bits of the instruction pointers (IAOQ0 and IAOQ1). On Linux we use privilege level 0 for the kernel and privilege level 3 for user-space. So userspace should not be allowed to modify IAOQ0 or IAOQ1 of a ptraced process to change it's privilege level to e.g. 0 to try to gain kernel privileges. This patch prevents such modifications by always setting the two lowest bits to one (which relates to privilege level 3 for user-space) if IAOQ0 or IAOQ1 are modified via ptrace calls in the native and compat ptrace paths. Link: https://bugs.gentoo.org/481768 Reported-by: Jeroen Roovers Cc: Tested-by: Rolf Eike Beer Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman --- arch/parisc/kernel/ptrace.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) --- a/arch/parisc/kernel/ptrace.c +++ b/arch/parisc/kernel/ptrace.c @@ -170,6 +170,9 @@ long arch_ptrace(struct task_struct *chi if ((addr & (sizeof(unsigned long)-1)) || addr >= sizeof(struct pt_regs)) break; + if (addr == PT_IAOQ0 || addr == PT_IAOQ1) { + data |= 3; /* ensure userspace privilege */ + } if ((addr >= PT_GR1 && addr <= PT_GR31) || addr == PT_IAOQ0 || addr == PT_IAOQ1 || (addr >= PT_FR0 && addr <= PT_FR31 + 4) || @@ -231,16 +234,18 @@ long arch_ptrace(struct task_struct *chi static compat_ulong_t translate_usr_offset(compat_ulong_t offset) { - if (offset < 0) - return sizeof(struct pt_regs); - else if (offset <= 32*4) /* gr[0..31] */ - return offset * 2 + 4; - else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */ - return offset + 32*4; - else if (offset < sizeof(struct pt_regs)/2 + 32*4) - return offset * 2 + 4 - 32*8; + compat_ulong_t pos; + + if (offset < 32*4) /* gr[0..31] */ + pos = offset * 2 + 4; + else if (offset < 32*4+32*8) /* fr[0] ... fr[31] */ + pos = (offset - 32*4) + PT_FR0; + else if (offset < sizeof(struct pt_regs)/2 + 32*4) /* sr[0] ... ipsw */ + pos = (offset - 32*4 - 32*8) * 2 + PT_SR0 + 4; else - return sizeof(struct pt_regs); + pos = sizeof(struct pt_regs); + + return pos; } long compat_arch_ptrace(struct task_struct *child, compat_long_t request, @@ -284,9 +289,12 @@ long compat_arch_ptrace(struct task_stru addr = translate_usr_offset(addr); if (addr >= sizeof(struct pt_regs)) break; + if (addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4) { + data |= 3; /* ensure userspace privilege */ + } if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { /* Special case, fp regs are 64 bits anyway */ - *(__u64 *) ((char *) task_regs(child) + addr) = data; + *(__u32 *) ((char *) task_regs(child) + addr) = data; ret = 0; } else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||