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Violators will be prosecuted; Tue, 30 Aug 2016 11:11:14 -0600 X-IBM-Helo: d03dlp02.boulder.ibm.com X-IBM-MailFrom: groug@kaod.org Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id 84D483E4003E; Tue, 30 Aug 2016 11:11:07 -0600 (MDT) Received: from b01ledav004.gho.pok.ibm.com (b01ledav004.gho.pok.ibm.com [9.57.199.109]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u7UHB6Bj5898740; Tue, 30 Aug 2016 17:11:06 GMT Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A15C2112034; Tue, 30 Aug 2016 13:11:06 -0400 (EDT) Received: from bahia.lab.toulouse-stg.fr.ibm.com (unknown [9.101.4.41]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP id B6C1E112056; Tue, 30 Aug 2016 13:11:05 -0400 (EDT) From: Greg Kurz To: qemu-devel@nongnu.org Date: Tue, 30 Aug 2016 19:11:05 +0200 In-Reply-To: <147257704749.28515.17213711886150247423.stgit@bahia.lab.toulouse-stg.fr.ibm.com> References: <147257704749.28515.17213711886150247423.stgit@bahia.lab.toulouse-stg.fr.ibm.com> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16083017-0024-0000-0000-00001470C335 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00005677; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000184; SDB=6.00751697; UDB=6.00355311; IPR=6.00524502; BA=6.00004680; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00012519; XFM=3.00000011; UTC=2016-08-30 17:11:17 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16083017-0025-0000-0000-00004405BC88 Message-Id: <147257705420.28515.6347449121724165834.stgit@bahia.lab.toulouse-stg.fr.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-08-30_07:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608300164 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCH v4 1/3] 9pfs: forbid illegal path names 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 , Felix Wilhelm , "Michael S. Tsirkin" , Greg Kurz , P J P , "Aneesh Kumar K.V" Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Empty path components don't make sense for most commands and may cause undefined behavior, depending on the backend. Also, the walk request described in the 9P spec [1] clearly shows that the client is supposed to send individual path components: the official linux client never sends portions of path containing the / character for example. Moreover, the 9P spec [2] also states that a system can decide to restrict the set of supported characters used in path components, with an explicit mention "to remove slashes from name components". This patch introduces a new name_is_illegal() helper that checks the names sent by the client are not empty and don't contain unwanted chars. Since 9pfs is only supported on linux hosts, only the / character is checked at the moment. When support for other hosts (AKA. win32) is added, other chars may need to be blacklisted as well. If a client sends an illegal path component, the request will fail and ENOENT is returned to the client. [1] http://man.cat-v.org/plan_9/5/walk [2] http://man.cat-v.org/plan_9/5/intro Suggested-by: Peter Maydell Signed-off-by: Greg Kurz Reviewed-by: Eric Blake --- v4: dropped the checking of the symbolic link target name: because a target can be a full path and thus contain '/' and linux already complains if it is an empty string. When the symlink gets dereferenced, slashes are interpreted as the usual path component separator. --- hw/9pfs/9p.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index b6b02b46a9da..385269ea0ac3 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -1256,6 +1256,11 @@ static int v9fs_walk_marshal(V9fsPDU *pdu, uint16_t nwnames, V9fsQID *qids) return offset; } +static bool name_is_illegal(const char *name) +{ + return !*name || strchr(name, '/') != NULL; +} + static void v9fs_walk(void *opaque) { int name_idx; @@ -1289,6 +1294,10 @@ static void v9fs_walk(void *opaque) if (err < 0) { goto out_nofid; } + if (name_is_illegal(wnames[i].data)) { + err = -ENOENT; + goto out_nofid; + } offset += err; } } else if (nwnames > P9_MAXWELEM) { @@ -1483,6 +1492,11 @@ static void v9fs_lcreate(void *opaque) } trace_v9fs_lcreate(pdu->tag, pdu->id, dfid, flags, mode, gid); + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + fidp = get_fid(pdu, dfid); if (fidp == NULL) { err = -ENOENT; @@ -2077,6 +2091,11 @@ static void v9fs_create(void *opaque) } trace_v9fs_create(pdu->tag, pdu->id, fid, name.data, perm, mode); + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + fidp = get_fid(pdu, fid); if (fidp == NULL) { err = -EINVAL; @@ -2242,6 +2261,11 @@ static void v9fs_symlink(void *opaque) } trace_v9fs_symlink(pdu->tag, pdu->id, dfid, name.data, symname.data, gid); + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + dfidp = get_fid(pdu, dfid); if (dfidp == NULL) { err = -EINVAL; @@ -2316,6 +2340,11 @@ static void v9fs_link(void *opaque) } trace_v9fs_link(pdu->tag, pdu->id, dfid, oldfid, name.data); + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + dfidp = get_fid(pdu, dfid); if (dfidp == NULL) { err = -ENOENT; @@ -2398,6 +2427,12 @@ static void v9fs_unlinkat(void *opaque) if (err < 0) { goto out_nofid; } + + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + dfidp = get_fid(pdu, dfid); if (dfidp == NULL) { err = -EINVAL; @@ -2504,6 +2539,12 @@ static void v9fs_rename(void *opaque) if (err < 0) { goto out_nofid; } + + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + fidp = get_fid(pdu, fid); if (fidp == NULL) { err = -ENOENT; @@ -2616,6 +2657,11 @@ static void v9fs_renameat(void *opaque) goto out_err; } + if (name_is_illegal(old_name.data) || name_is_illegal(new_name.data)) { + err = -ENOENT; + goto out_err; + } + v9fs_path_write_lock(s); err = v9fs_complete_renameat(pdu, olddirfid, &old_name, newdirfid, &new_name); @@ -2826,6 +2872,11 @@ static void v9fs_mknod(void *opaque) } trace_v9fs_mknod(pdu->tag, pdu->id, fid, mode, major, minor); + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + fidp = get_fid(pdu, fid); if (fidp == NULL) { err = -ENOENT; @@ -2977,6 +3028,11 @@ static void v9fs_mkdir(void *opaque) } trace_v9fs_mkdir(pdu->tag, pdu->id, fid, name.data, mode, gid); + if (name_is_illegal(name.data)) { + err = -ENOENT; + goto out_nofid; + } + fidp = get_fid(pdu, fid); if (fidp == NULL) { err = -ENOENT;