From nobody Tue Feb 10 08:31:20 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 1487602185610383.09276479200264; Mon, 20 Feb 2017 06:49:45 -0800 (PST) Received: from localhost ([::1]:38975 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cfpHc-0005lc-3W for importer@patchew.org; Mon, 20 Feb 2017 09:49:44 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54115) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cfp90-0006a1-PV for qemu-devel@nongnu.org; Mon, 20 Feb 2017 09:40:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cfp8x-0003hE-HO for qemu-devel@nongnu.org; Mon, 20 Feb 2017 09:40:50 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:59878) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cfp8x-0003gs-6m for qemu-devel@nongnu.org; Mon, 20 Feb 2017 09:40:47 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1KEcrfd128144 for ; Mon, 20 Feb 2017 09:40:46 -0500 Received: from e35.co.us.ibm.com (e35.co.us.ibm.com [32.97.110.153]) by mx0a-001b2d01.pphosted.com with ESMTP id 28pp6mtgs1-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 20 Feb 2017 09:40:45 -0500 Received: from localhost by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 20 Feb 2017 07:40:41 -0700 Received: from b01cxnp22034.gho.pok.ibm.com (b01cxnp22034.gho.pok.ibm.com [9.57.198.24]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id 19CB219D8040; Mon, 20 Feb 2017 07:39:53 -0700 (MST) Received: from b01ledav004.gho.pok.ibm.com (b01ledav004.gho.pok.ibm.com [9.57.199.109]) by b01cxnp22034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v1KEeeiY40566870; Mon, 20 Feb 2017 14:40:40 GMT Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C6BF9112056; Mon, 20 Feb 2017 09:40:39 -0500 (EST) Received: from bahia.lan (unknown [9.164.137.25]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP id 8FDDA112051; Mon, 20 Feb 2017 09:40:38 -0500 (EST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Mon, 20 Feb 2017 15:40:38 +0100 In-Reply-To: <148760155821.31154.13876757160410915057.stgit@bahia.lan> References: <148760155821.31154.13876757160410915057.stgit@bahia.lan> User-Agent: StGit/0.17.1-20-gc0b1b-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17022014-0012-0000-0000-000013B54CE1 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006651; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000204; SDB=6.00824569; UDB=6.00403651; IPR=6.00602024; BA=6.00005157; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00014359; XFM=3.00000011; UTC=2017-02-20 14:40:43 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17022014-0013-0000-0000-00004B92B52F Message-Id: <148760163823.31154.16688868823479209435.stgit@bahia.lan> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-02-20_13:, , 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=8.0.1-1612050000 definitions=main-1702200144 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 10/29] 9pfs: local: lsetxattr: 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: Jann Horn , Prasad J Pandit , Greg Kurz , "Aneesh Kumar K.V" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 The local_lsetxattr() callback is vulnerable to symlink attacks because it calls lsetxattr() which follows symbolic links in all path elements but the rightmost one. This patch converts local_lsetxattr() to rely on opendir_nofollow() and fsetxattrat_nofollow() instead. This partly fixes CVE-2016-9602. Signed-off-by: Greg Kurz Reviewed-by: Stefan Hajnoczi --- hw/9pfs/9p-posix-acl.c | 18 ++++-------------- hw/9pfs/9p-xattr-user.c | 8 +------- hw/9pfs/9p-xattr.c | 8 +------- 3 files changed, 6 insertions(+), 28 deletions(-) diff --git a/hw/9pfs/9p-posix-acl.c b/hw/9pfs/9p-posix-acl.c index 9435e27a368c..0154e2a7605f 100644 --- a/hw/9pfs/9p-posix-acl.c +++ b/hw/9pfs/9p-posix-acl.c @@ -50,13 +50,8 @@ static ssize_t mp_pacl_listxattr(FsContext *ctx, const c= har *path, static int mp_pacl_setxattr(FsContext *ctx, const char *path, const char *= name, void *value, size_t size, int flags) { - char *buffer; - int ret; - - buffer =3D rpath(ctx, path); - ret =3D lsetxattr(buffer, MAP_ACL_ACCESS, value, size, flags); - g_free(buffer); - return ret; + return local_setxattr_nofollow(ctx, path, MAP_ACL_ACCESS, value, size, + flags); } =20 static int mp_pacl_removexattr(FsContext *ctx, @@ -108,13 +103,8 @@ static ssize_t mp_dacl_listxattr(FsContext *ctx, const= char *path, static int mp_dacl_setxattr(FsContext *ctx, const char *path, const char *= name, void *value, size_t size, int flags) { - char *buffer; - int ret; - - buffer =3D rpath(ctx, path); - ret =3D lsetxattr(buffer, MAP_ACL_DEFAULT, value, size, flags); - g_free(buffer); - return ret; + return local_setxattr_nofollow(ctx, path, MAP_ACL_DEFAULT, value, size, + flags); } =20 static int mp_dacl_removexattr(FsContext *ctx, diff --git a/hw/9pfs/9p-xattr-user.c b/hw/9pfs/9p-xattr-user.c index 4071fbc4c086..1840a5db66f3 100644 --- a/hw/9pfs/9p-xattr-user.c +++ b/hw/9pfs/9p-xattr-user.c @@ -67,9 +67,6 @@ static ssize_t mp_user_listxattr(FsContext *ctx, const ch= ar *path, static int mp_user_setxattr(FsContext *ctx, const char *path, const char *= name, void *value, size_t size, int flags) { - char *buffer; - int ret; - if (strncmp(name, "user.virtfs.", 12) =3D=3D 0) { /* * Don't allow fetch of user.virtfs namesapce @@ -78,10 +75,7 @@ static int mp_user_setxattr(FsContext *ctx, const char *= path, const char *name, errno =3D EACCES; return -1; } - buffer =3D rpath(ctx, path); - ret =3D lsetxattr(buffer, name, value, size, flags); - g_free(buffer); - return ret; + return local_setxattr_nofollow(ctx, path, name, value, size, flags); } =20 static int mp_user_removexattr(FsContext *ctx, diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c index 803d4bbbc50b..72ef820f16d7 100644 --- a/hw/9pfs/9p-xattr.c +++ b/hw/9pfs/9p-xattr.c @@ -328,13 +328,7 @@ ssize_t pt_getxattr(FsContext *ctx, const char *path, = const char *name, int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *= value, size_t size, int flags) { - char *buffer; - int ret; - - buffer =3D rpath(ctx, path); - ret =3D lsetxattr(buffer, name, value, size, flags); - g_free(buffer); - return ret; + return local_setxattr_nofollow(ctx, path, name, value, size, flags); } =20 int pt_removexattr(FsContext *ctx, const char *path, const char *name)