From nobody Sun Feb 8 19:55:34 2026 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 1490051629992372.9760291412084; Mon, 20 Mar 2017 16:13:49 -0700 (PDT) Received: from localhost ([::1]:35482 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cq6Um-0004cV-Lx for importer@patchew.org; Mon, 20 Mar 2017 19:13:48 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40330) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cq6QW-0001Qr-DF for qemu-devel@nongnu.org; Mon, 20 Mar 2017 19:09:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cq6QR-0004gK-Nl for qemu-devel@nongnu.org; Mon, 20 Mar 2017 19:09:23 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:40011) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cq6QR-0004f8-EE for qemu-devel@nongnu.org; Mon, 20 Mar 2017 19:09:19 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v2KN8Xdt130192 for ; Mon, 20 Mar 2017 19:09:18 -0400 Received: from e38.co.us.ibm.com (e38.co.us.ibm.com [32.97.110.159]) by mx0a-001b2d01.pphosted.com with ESMTP id 29ahw0awc4-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 20 Mar 2017 19:09:18 -0400 Received: from localhost by e38.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 20 Mar 2017 17:09:15 -0600 Received: from b03ledav001.gho.boulder.ibm.com (b03ledav001.gho.boulder.ibm.com [9.17.130.232]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v2KN9F9t10420598; Mon, 20 Mar 2017 16:09:15 -0700 Received: from b03ledav001.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 211406E03D; Mon, 20 Mar 2017 17:09:15 -0600 (MDT) Received: from localhost (unknown [9.53.92.194]) by b03ledav001.gho.boulder.ibm.com (Postfix) with ESMTP id 08ABD6E038; Mon, 20 Mar 2017 17:09:15 -0600 (MDT) From: Michael Roth To: qemu-devel@nongnu.org Date: Mon, 20 Mar 2017 18:07:37 -0500 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1490051325-3770-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1490051325-3770-1-git-send-email-mdroth@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17032023-0028-0000-0000-00000740CEEA X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006819; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000206; SDB=6.00836553; UDB=6.00411161; IPR=6.00614321; BA=6.00005224; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00014732; XFM=3.00000013; UTC=2017-03-20 23:09:17 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17032023-0029-0000-0000-000034725264 Message-Id: <1490051325-3770-14-git-send-email-mdroth@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-03-20_16:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=3 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703200196 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.156.1 Subject: [Qemu-devel] [PATCH 13/81] 9pfs: local: utimensat: 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: Greg Kurz , qemu-stable@nongnu.org, 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" From: Greg Kurz The local_utimensat() callback is vulnerable to symlink attacks because it calls qemu_utimens()->utimensat(AT_SYMLINK_NOFOLLOW) which follows symbolic links in all path elements but the rightmost one or qemu_utimens()->utimes() which follows symbolic links for all path elements. This patch converts local_utimensat() to rely on opendir_nofollow() and utimensat(AT_SYMLINK_NOFOLLOW) directly instead of using qemu_utimens(). It is hence assumed that the OS supports utimensat(), i.e. has glibc 2.6 or higher and linux 2.6.22 or higher, which seems reasonable nowadays. This partly fixes CVE-2016-9602. Signed-off-by: Greg Kurz Reviewed-by: Stefan Hajnoczi (cherry picked from commit a33eda0dd99e00faa3bacae43d19490bb9500e07) Signed-off-by: Greg Kurz Signed-off-by: Michael Roth --- hw/9pfs/9p-local.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c index 9caee0e..fa1477f 100644 --- a/hw/9pfs/9p-local.c +++ b/hw/9pfs/9p-local.c @@ -960,13 +960,20 @@ static int local_chown(FsContext *fs_ctx, V9fsPath *f= s_path, FsCred *credp) static int local_utimensat(FsContext *s, V9fsPath *fs_path, const struct timespec *buf) { - char *buffer; - int ret; - char *path =3D fs_path->data; + char *dirpath =3D g_path_get_dirname(fs_path->data); + char *name =3D g_path_get_basename(fs_path->data); + int dirfd, ret =3D -1; =20 - buffer =3D rpath(s, path); - ret =3D qemu_utimens(buffer, buf); - g_free(buffer); + dirfd =3D local_opendir_nofollow(s, dirpath); + if (dirfd =3D=3D -1) { + goto out; + } + + ret =3D utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW); + close_preserve_errno(dirfd); +out: + g_free(dirpath); + g_free(name); return ret; } =20 --=20 2.7.4