From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753972AbdEQL0k (ORCPT ); Wed, 17 May 2017 07:26:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:56670 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753400AbdEQL0h (ORCPT ); Wed, 17 May 2017 07:26:37 -0400 From: Luis Henriques To: "Yan, Zheng" , Sage Weil , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Luis Henriques Subject: [PATCH] ceph: check i_nlink while converting a file handle to dentry Date: Wed, 17 May 2017 12:21:07 +0100 Message-Id: <20170517112107.31025-1-lhenriques@suse.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Converting a file handle to a dentry can be done call after the inode unlink. This means that __fh_to_dentry() requires an extra check to verify the number of links is not 0. The issue can be easily reproduced using xfstest generic/426, which does something like: name_to_handle_at(&fh) echo 3 > /proc/sys/vm/drop_caches unlink() open_by_handle_at(&fh) The call to open_by_handle_at() should fail, as the file doesn't exist anymore. Cc: stable@vger.kernel.org Link: http://tracker.ceph.com/issues/19958 Signed-off-by: Luis Henriques --- fs/ceph/export.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ceph/export.c b/fs/ceph/export.c index e8f11fa565c5..7df550c13d7f 100644 --- a/fs/ceph/export.c +++ b/fs/ceph/export.c @@ -91,6 +91,10 @@ static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) ceph_mdsc_put_request(req); if (!inode) return ERR_PTR(-ESTALE); + if (inode->i_nlink == 0) { + iput(inode); + return ERR_PTR(-ESTALE); + } } return d_obtain_alias(inode);