From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3390871-1521217262-2-17330221875189976214 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='com', MailFrom='org' X-Spam-charsets: plain='utf-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521217262; b=GZPC1xHXkxbv0F8/WVije7R3OPhyA9vf09UEgvHoIozo/0H 4zGih6oUQXNkSty0UwSaTutHCyfSJrjPKZNanzfPHAGg4nKAA8dzsmd9uWkOhsYq iIIPnk6c1iPENFkjaHnYAtxRI69MYFS4WSWI7iRG+s4GHdO3sKeIBnr2/Xyc/IoU LWBymYro/xb8RuDqLGYw4d3up1GTkjEBu+2pfx5FCkFKzIaHpsdbhzDziRhFRcL+ QlEwrndtV6J1iYtLw+8vYh0sl/lKmcYzBZRuzSlYOZQ073sHFj02pzrJstDT6z9C Ot3USccy7/0M4blXMxDCXl6jAOynNNPEb9M50rg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=subject:to:cc:references:from:message-id :date:mime-version:in-reply-to:content-type :content-transfer-encoding:sender:list-id; s=arctest; t= 1521217262; bh=akORTUsbKZVgDqTW7F1yqBpuLsGBdpFQx75PoM2t0xI=; b=b Rg/91vPP2LRk8wQlJR2KrL7C6x13dyl9pZcPBExooZavJKqyOaWeZ77fGCyAjZgr CDcBcfjuidbGBMT+52dLVJbeNYrHBvyaQYntsNz1ZW7vMYbiodO133al92Jn2us0 zSp9fgD/3pImN4CRIyTH2PMWowHEwsM7OhHKuJ2QDEHpe9qSLu48otNvZOikGPYm AyFr3GDzsA87ACYMcl4PSoDl2YSPrhTi4bWnGntqWsnQIBFPYWVDH0ZUYe+OdDRW HeELs+6pueiW0Ac1yBqBp7rTXvcpWWDCXOp+gdPF7530pu9hOqXCvGpA/VRuka7O Lffg7qJOyHz8wXoVPiAsA== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=oracle.com header.i=@oracle.com header.b=Wt6MeYm3 x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=corp-2017-10-26; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=oracle.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=oracle.com header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=oracle.com header.i=@oracle.com header.b=Wt6MeYm3 x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=corp-2017-10-26; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=oracle.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=oracle.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754655AbeCPQTf (ORCPT ); Fri, 16 Mar 2018 12:19:35 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:49202 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754520AbeCPQTc (ORCPT ); Fri, 16 Mar 2018 12:19:32 -0400 Subject: Re: [PATCH v3] hugetlbfs: check for pgoff value overflow To: Michal Hocko Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, bugzilla-daemon@bugzilla.kernel.org, "Kirill A . Shutemov" , Nic Losby , Yisheng Xie , Andrew Morton , stable@vger.kernel.org References: <20180306133135.4dc344e478d98f0e29f47698@linux-foundation.org> <20180309002726.7248-1-mike.kravetz@oracle.com> <20180316101757.GE23100@dhcp22.suse.cz> From: Mike Kravetz Message-ID: <12826dc6-c81e-c22a-2ec1-8e1cf0f07dfc@oracle.com> Date: Fri, 16 Mar 2018 09:19:07 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <20180316101757.GE23100@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8833 signatures=668690 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1803160153 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 03/16/2018 03:17 AM, Michal Hocko wrote: > On Thu 08-03-18 16:27:26, Mike Kravetz wrote: > > OK, looks good to me. Hairy but seems to be the easiest way around this. > Acked-by: Michal Hocko > >> +/* >> + * Mask used when checking the page offset value passed in via system >> + * calls. This value will be converted to a loff_t which is signed. >> + * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the >> + * value. The extra bit (- 1 in the shift value) is to take the sign >> + * bit into account. >> + */ >> +#define PGOFF_LOFFT_MAX (PAGE_MASK << (BITS_PER_LONG - (2 * PAGE_SHIFT) - 1)) Thanks Michal, However, kbuild found a problem with this definition on certain configs. Consider a config where, BITS_PER_LONG = 32 (32bit config) PAGE_SHIFT = 16 (64K pages) This results in the negative shift value. Not something I would not immediately think of, but a valid config. The definition has been changed to, #define PGOFF_LOFFT_MAX \ (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1))) as discussed here, http://lkml.kernel.org/r/432fb2a3-b729-9c3a-7d60-890b8f9b10dd@oracle.com -- Mike Kravetz