From 04f522476a267e5d2d15d4b0c9e1500027e69879 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Wed, 19 Apr 2017 10:01:48 +0800 Subject: ceph: fix recursion between ceph_set_acl() and __ceph_setattr() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Cc: stable@vger.kernel.org # needs backporting for < 4.9 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 [luis: introduce __ceph_setattr() and make ceph_set_acl() call it, as suggested by Yan.] Signed-off-by: Luis Henriques Signed-off-by: Greg Kroah-Hartman Reviewed-by: “Yan, Zheng” --- fs/ceph/acl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/ceph/acl.c') diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c index 4d8caeb94a11..bdb9c94335f1 100644 --- a/fs/ceph/acl.c +++ b/fs/ceph/acl.c @@ -128,7 +128,7 @@ int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type) if (new_mode != old_mode) { newattrs.ia_mode = new_mode; newattrs.ia_valid = ATTR_MODE; - ret = ceph_setattr(dentry, &newattrs); + ret = __ceph_setattr(dentry, &newattrs); if (ret) goto out_dput; } @@ -138,7 +138,7 @@ int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type) if (new_mode != old_mode) { newattrs.ia_mode = old_mode; newattrs.ia_valid = ATTR_MODE; - ceph_setattr(dentry, &newattrs); + __ceph_setattr(dentry, &newattrs); } goto out_dput; } -- cgit v1.2.3