From patchwork Wed Aug 23 04:48:14 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ronnie Sahlberg X-Patchwork-Id: 9916543 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 5E3FB60327 for ; Wed, 23 Aug 2017 04:48:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4EE3B28847 for ; Wed, 23 Aug 2017 04:48:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 42EF928953; Wed, 23 Aug 2017 04:48:28 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D533E28847 for ; Wed, 23 Aug 2017 04:48:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751200AbdHWEs1 (ORCPT ); Wed, 23 Aug 2017 00:48:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43066 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750931AbdHWEs0 (ORCPT ); Wed, 23 Aug 2017 00:48:26 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D3F080F6D; Wed, 23 Aug 2017 04:48:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 9D3F080F6D Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lsahlber@redhat.com Received: from localhost.localdomain (vpn2-54-33.bne.redhat.com [10.64.54.33]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4C36A7FD47; Wed, 23 Aug 2017 04:48:25 +0000 (UTC) From: Ronnie Sahlberg To: linux-cifs Cc: Steve French Subject: [PATCH] cifs: return ENAMETOOLONG for overlong names in cifs_open()/cifs_lookup() Date: Wed, 23 Aug 2017 14:48:14 +1000 Message-Id: <20170823044814.9609-1-lsahlber@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 23 Aug 2017 04:48:26 +0000 (UTC) Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add checking for the path component length and verify it is <= the maximum that the server advertizes via FileFsAttributeInformation. With this patch cifs.ko will now return ENAMETOOLONG instead of ENOENT when users to access an overlong path. To test this, try to cd into a (non-existing) directory on a CIFS share that has a too long name: cd /mnt/aaaaaaaaaaaaaaa... and it now should show a good error message from the shell: bash: cd: /mnt/aaaaaaaaaaaaaaaa...aaaaaa: File name too long rh bz 1153996 Signed-off-by: Ronnie Sahlberg --- fs/cifs/dir.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 56366e984076..569d3fb736be 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -194,15 +194,20 @@ build_path_from_dentry_optional_prefix(struct dentry *direntry, bool prefix) } /* + * Don't allow path components longer than the server max. * Don't allow the separator character in a path component. * The VFS will not allow "/", but "\" is allowed by posix. */ static int -check_name(struct dentry *direntry) +check_name(struct dentry *direntry, struct cifs_tcon *tcon) { struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb); int i; + if (unlikely(direntry->d_name.len > + tcon->fsAttrInfo.MaxPathNameComponentLength)) + return -ENAMETOOLONG; + if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) { for (i = 0; i < direntry->d_name.len; i++) { if (direntry->d_name.name[i] == '\\') { @@ -500,10 +505,6 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry, return finish_no_open(file, res); } - rc = check_name(direntry); - if (rc) - return rc; - xid = get_xid(); cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n", @@ -516,6 +517,11 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry, } tcon = tlink_tcon(tlink); + + rc = check_name(direntry, tcon); + if (rc) + goto out_free_xid; + server = tcon->ses->server; if (server->ops->new_lease_key) @@ -776,7 +782,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, } pTcon = tlink_tcon(tlink); - rc = check_name(direntry); + rc = check_name(direntry, pTcon); if (rc) goto lookup_out;