From nobody Thu Nov 6 18:51:49 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1488237656948323.019872275906; Mon, 27 Feb 2017 15:20:56 -0800 (PST) Received: from localhost ([::1]:57528 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ciUb9-0000LZ-En for importer@patchew.org; Mon, 27 Feb 2017 18:20:55 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46953) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ciUHo-0000bd-84 for qemu-devel@nongnu.org; Mon, 27 Feb 2017 18:00:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ciUHl-00040b-CQ for qemu-devel@nongnu.org; Mon, 27 Feb 2017 18:00:56 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34058 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ciUHl-0003zx-6b for qemu-devel@nongnu.org; Mon, 27 Feb 2017 18:00:53 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1RMrc5D080992 for ; Mon, 27 Feb 2017 18:00:52 -0500 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 28vm1wankr-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 27 Feb 2017 18:00:52 -0500 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 27 Feb 2017 23:00:47 -0000 Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 23F8617D8042; Mon, 27 Feb 2017 23:04:00 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v1RN0l5D58589292; Mon, 27 Feb 2017 23:00:47 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 37D9511C058; Mon, 27 Feb 2017 21:58:28 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 251AB11C04A; Mon, 27 Feb 2017 21:58:28 +0000 (GMT) Received: from smtp.lab.toulouse-stg.fr.ibm.com (unknown [9.101.4.1]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 27 Feb 2017 21:58:28 +0000 (GMT) Received: from bahia.lan (icon-9-164-183-34.megacenter.de.ibm.com [9.164.183.34]) by smtp.lab.toulouse-stg.fr.ibm.com (Postfix) with ESMTP id 4FF0D220750; Tue, 28 Feb 2017 00:00:46 +0100 (CET) From: Greg Kurz To: qemu-devel@nongnu.org Date: Tue, 28 Feb 2017 00:00:08 +0100 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488236421-30983-1-git-send-email-groug@kaod.org> References: <1488236421-30983-1-git-send-email-groug@kaod.org> X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17022723-0040-0000-0000-0000033387A7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17022723-0041-0000-0000-0000244F4FC8 Message-Id: <1488236421-30983-19-git-send-email-groug@kaod.org> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-02-27_17:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=13 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1702270213 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PULL 18/31] 9pfs: local: truncate: don't follow symlinks X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , "Aneesh Kumar K.V" , Greg Kurz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The local_truncate() callback is vulnerable to symlink attacks because it calls truncate() which follows symbolic links in all path elements. This patch converts local_truncate() to rely on open_nofollow() and ftruncate() instead. This partly fixes CVE-2016-9602. Signed-off-by: Greg Kurz Reviewed-by: Stefan Hajnoczi --- hw/9pfs/9p-local.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c index ae5d26821791..c6c114839287 100644 --- a/hw/9pfs/9p-local.c +++ b/hw/9pfs/9p-local.c @@ -894,13 +894,14 @@ err_out: =20 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size) { - char *buffer; - int ret; - char *path =3D fs_path->data; + int fd, ret; =20 - buffer =3D rpath(ctx, path); - ret =3D truncate(buffer, size); - g_free(buffer); + fd =3D local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0); + if (fd =3D=3D -1) { + return -1; + } + ret =3D ftruncate(fd, size); + close_preserve_errno(fd); return ret; } =20 --=20 2.7.4