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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 B41D1C47256 for ; Tue, 5 May 2020 06:49:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93A2C2075A for ; Tue, 5 May 2020 06:49:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726635AbgEEGts (ORCPT ); Tue, 5 May 2020 02:49:48 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:27348 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725320AbgEEGts (ORCPT ); Tue, 5 May 2020 02:49:48 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0456Xx35152663; Tue, 5 May 2020 02:49:11 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 30s1swjf9s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 May 2020 02:49:11 -0400 Received: from m0098419.ppops.net (m0098419.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 0456aN1p162949; Tue, 5 May 2020 02:49:10 -0400 Received: from ppma01fra.de.ibm.com (46.49.7a9f.ip4.static.sl-reverse.com [159.122.73.70]) by mx0b-001b2d01.pphosted.com with ESMTP id 30s1swjf8q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 May 2020 02:49:10 -0400 Received: from pps.filterd (ppma01fra.de.ibm.com [127.0.0.1]) by ppma01fra.de.ibm.com (8.16.0.27/8.16.0.27) with SMTP id 0456jPww029773; Tue, 5 May 2020 06:49:08 GMT Received: from b06avi18878370.portsmouth.uk.ibm.com (b06avi18878370.portsmouth.uk.ibm.com [9.149.26.194]) by ppma01fra.de.ibm.com with ESMTP id 30s0g5ak8s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 May 2020 06:49:08 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 0456n54R65536390 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 5 May 2020 06:49:05 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A50B2AE04D; Tue, 5 May 2020 06:49:05 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0AB1BAE045; Tue, 5 May 2020 06:49:05 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av26.portsmouth.uk.ibm.com (Postfix) with SMTP; Tue, 5 May 2020 06:49:04 +0000 (GMT) Date: Tue, 5 May 2020 08:49:04 +0200 From: Sven Schnelle To: Christian Borntraeger Cc: Oleg Nesterov , Srikar Dronamraju , Guo Ren , "David S. Miller" , Linus Torvalds , Steven Rostedt , "Eric W. Biederman" , Peter Zijlstra , Ingo Molnar , Jann Horn , Al Viro , Jens Axboe , Security Officers , Andrea Arcangeli , Ananth N Mavinakayanahalli , Naveen Rao , Andrew Morton , linux-kernel@vger.kernel.org, Vasily Gorbik Subject: Re: [PATCH] uprobes: ensure that uprobe->offset and ->ref_ctr_offset are properly aligned Message-ID: <20200505064904.GA40867@tuxmaker.boeblingen.de.ibm.com> References: <20200428091149.GB19958@linux.vnet.ibm.com> <20200428123914.GA27920@redhat.com> <20200504164724.GA28697@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.676 definitions=2020-05-05_02:2020-05-04,2020-05-05 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 lowpriorityscore=0 malwarescore=0 phishscore=0 adultscore=0 impostorscore=0 mlxlogscore=871 bulkscore=0 clxscore=1011 suspectscore=0 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2005050051 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, May 04, 2020 at 08:40:44PM +0200, Christian Borntraeger wrote: > > > On 04.05.20 18:47, Oleg Nesterov wrote: > > uprobe_write_opcode() must not cross page boundary; prepare_uprobe() > > relies on arch_uprobe_analyze_insn() which should validate "vaddr" but > > some architectures (csky, s390, and sparc) don't do this. > > I think the idea was that the uprobe instruction is 2 bytes and instructions > are always aligned to 2 bytes on s390. (we can have 2,4 or 6 bytes). > > > > > We can remove the BUG_ON() check in prepare_uprobe() and validate the > > offset early in __uprobe_register(). The new IS_ALIGNED() check matches > > the alignment check in arch_prepare_kprobe() on supported architectures, > > so I think that all insns must be aligned to UPROBE_SWBP_INSN_SIZE. > > Not sure if it would have been possible to try to create a uprobe on an > odd address. If yes, then the new IS_ALIGNED check certainly makes this > better for s390, so the patch looks sane. Adding Vasily and Sven to double > check. I did a quick test, and without this patch it is possible to place a uprobe at an odd address. With the patch it fails with EINVAL, which is more reasonable. Regards Sven