Path: csiph.com!goblin2!goblin.stu.neva.ru!news.unit0.net!news.panservice.it!bofh.it!news.nic.it!robomod From: Greg Kroah-Hartman Newsgroups: linux.kernel Subject: [PATCH 4.9 50/54] ceph: fix recursion between ceph_set_acl() and __ceph_setattr() Date: Mon, 01 May 2017 23:40:04 +0200 Message-ID: References: X-Original-To: linux-kernel@vger.kernel.org X-Mailer: git-send-email 2.12.2 User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 77 Organization: linux.* mail to news gateway X-Original-Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jerry Lee , "Yan, Zheng" , Jeff Layton , Luis Henriques , Ilya Dryomov X-Original-Date: Mon, 1 May 2017 14:31:57 -0700 X-Original-Message-ID: <20170501212633.801555783@linuxfoundation.org> X-Original-References: <20170501212631.798128131@linuxfoundation.org> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1633924 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yan, Zheng commit 8179a101eb5f4ef0ac9a915fcea9a9d3109efa90 upstream. ceph_set_acl() calls __ceph_setattr() if the setacl operation needs to modify inode's i_mode. __ceph_setattr() updates inode's i_mode, then calls posix_acl_chmod(). The problem is that __ceph_setattr() calls posix_acl_chmod() before sending the setattr request. The get_acl() call in posix_acl_chmod() can trigger a getxattr request. The reply of the getxattr request can restore inode's i_mode to its old value. The set_acl() call in posix_acl_chmod() sees old value of inode's i_mode, so it calls __ceph_setattr() again. Link: http://tracker.ceph.com/issues/19688 Reported-by: Jerry Lee Signed-off-by: "Yan, Zheng" Reviewed-by: Jeff Layton Tested-by: Luis Henriques Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman --- fs/ceph/inode.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -2080,11 +2080,6 @@ int __ceph_setattr(struct inode *inode, if (inode_dirty_flags) __mark_inode_dirty(inode, inode_dirty_flags); - if (ia_valid & ATTR_MODE) { - err = posix_acl_chmod(inode, attr->ia_mode); - if (err) - goto out_put; - } if (mask) { req->r_inode = inode; @@ -2098,13 +2093,11 @@ int __ceph_setattr(struct inode *inode, ceph_cap_string(dirtied), mask); ceph_mdsc_put_request(req); - if (mask & CEPH_SETATTR_SIZE) - __ceph_do_pending_vmtruncate(inode); - ceph_free_cap_flush(prealloc_cf); - return err; -out_put: - ceph_mdsc_put_request(req); ceph_free_cap_flush(prealloc_cf); + + if (err >= 0 && (mask & CEPH_SETATTR_SIZE)) + __ceph_do_pending_vmtruncate(inode); + return err; } @@ -2123,7 +2116,12 @@ int ceph_setattr(struct dentry *dentry, if (err != 0) return err; - return __ceph_setattr(inode, attr); + err = __ceph_setattr(inode, attr); + + if (err >= 0 && (attr->ia_valid & ATTR_MODE)) + err = posix_acl_chmod(inode, attr->ia_mode); + + return err; } /*