From patchwork Thu Jul 28 18:35:34 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 9251553 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B01986077C for ; Thu, 28 Jul 2016 18:35:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A1F3A1FFC9 for ; Thu, 28 Jul 2016 18:35:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9593627DF9; Thu, 28 Jul 2016 18:35:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from oss.sgi.com (oss.sgi.com [192.48.182.195]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6E0F81FFC9 for ; Thu, 28 Jul 2016 18:35:49 +0000 (UTC) Received: from oss.sgi.com (localhost [IPv6:::1]) by oss.sgi.com (Postfix) with ESMTP id C614B7CA1; Thu, 28 Jul 2016 13:35:47 -0500 (CDT) X-Original-To: xfs@oss.sgi.com Delivered-To: xfs@oss.sgi.com Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 409B17CA0 for ; Thu, 28 Jul 2016 13:35:45 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay2.corp.sgi.com (Postfix) with ESMTP id 05023304039 for ; Thu, 28 Jul 2016 11:35:41 -0700 (PDT) X-ASG-Debug-ID: 1469730940-0bf57b369c19c6a0001-NocioJ Received: from aserp1040.oracle.com (aserp1040.oracle.com [141.146.126.69]) by cuda.sgi.com with ESMTP id vjzDtajFjLnPELSa (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Thu, 28 Jul 2016 11:35:40 -0700 (PDT) X-Barracuda-Envelope-From: darrick.wong@oracle.com X-Barracuda-Effective-Source-IP: aserp1040.oracle.com[141.146.126.69] X-Barracuda-Apparent-Source-IP: 141.146.126.69 Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u6SIZcQE031404 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 28 Jul 2016 18:35:38 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0021.oracle.com (8.13.8/8.13.8) with ESMTP id u6SIZc7w004393 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 28 Jul 2016 18:35:38 GMT Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id u6SIZaqP031179; Thu, 28 Jul 2016 18:35:36 GMT Received: from localhost (/10.145.178.207) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 28 Jul 2016 11:35:36 -0700 Date: Thu, 28 Jul 2016 11:35:34 -0700 From: "Darrick J. Wong" To: Al Viro Subject: [PATCH] vfs: cap dedupe request structure size at PAGE_SIZE Message-ID: <20160728183534.GB15753@birch.djwong.org> X-ASG-Orig-Subj: [PATCH] vfs: cap dedupe request structure size at PAGE_SIZE MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Source-IP: userv0021.oracle.com [156.151.31.71] X-Barracuda-Connect: aserp1040.oracle.com[141.146.126.69] X-Barracuda-Start-Time: 1469730940 X-Barracuda-Encrypted: ECDHE-RSA-AES256-GCM-SHA384 X-Barracuda-URL: https://192.48.176.25:443/cgi-mod/mark.cgi X-Barracuda-Scan-Msg-Size: 1177 X-Virus-Scanned: by bsmtpd at sgi.com X-Barracuda-BRTS-Status: 1 X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=2.7 tests=BSF_SC0_MISMATCH_TO, UNPARSEABLE_RELAY X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.31585 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- 0.00 BSF_SC0_MISMATCH_TO Envelope rcpt doesn't match header 0.00 UNPARSEABLE_RELAY Informational: message has unparseable relay lines Cc: linux-api@vger.kernel.org, xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org, "Kirill A. Shutemov" , Vlastimil Babka X-BeenThere: xfs@oss.sgi.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com X-Virus-Scanned: ClamAV using ClamSMTP Kirill A. Shutemov reports that the kernel doesn't try to cap dest_count in any way, and uses the number to allocate kernel memory. This causes high order allocation warnings in the kernel log if someone passes in a big enough value. We should clamp the allocation at PAGE_SIZE to avoid stressing the VM. The two existing users of the dedupe ioctl never send more than 120 requests, so we can safely clamp dest_range at PAGE_SIZE, because with 4k pages we can handle up to 127 dedupe candidates. Given the max extent length of 16MB, we can end up doing 2GB of IO which is plenty. Reported-by: "Kirill A. Shutemov" Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Mark Fasheh --- fs/ioctl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ioctl.c b/fs/ioctl.c index db3d033..57409a7 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -582,6 +582,10 @@ static int ioctl_file_dedupe_range(struct file *file, void __user *arg) } size = offsetof(struct file_dedupe_range __user, info[count]); + if (size > PAGE_SIZE) { + ret = -ENOMEM; + goto out; + } same = memdup_user(argp, size); if (IS_ERR(same)) {