This is a note to let you know that I've just added the patch titled
ceph: fix recursion between ceph_set_acl() and __ceph_setattr()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ceph-fix-recursion-between-ceph_set_acl-and-__ceph_setattr.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8179a101eb5f4ef0ac9a915fcea9a9d3109efa90 Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@xxxxxxxxxx>
Date: Wed, 19 Apr 2017 10:01:48 +0800
Subject: ceph: fix recursion between ceph_set_acl() and __ceph_setattr()
From: Yan, Zheng <zyan@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx # needs backporting for < 4.9
Link: http://tracker.ceph.com/issues/19688
Reported-by: Jerry Lee <leisurelysw24@xxxxxxxxx>
Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
Tested-by: Luis Henriques <lhenriques@xxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
[luis: introduce __ceph_setattr() and make ceph_set_acl() call it, as
suggested by Yan.]
Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: “Yan, Zheng” <zyan@xxxxxxxxxx>
---
fs/ceph/acl.c | 4 ++--
fs/ceph/inode.c | 27 ++++++++++++++++-----------
fs/ceph/super.h | 1 +
3 files changed, 19 insertions(+), 13 deletions(-)
--- a/fs/ceph/acl.c
+++ b/fs/ceph/acl.c
@@ -128,7 +128,7 @@ int ceph_set_acl(struct inode *inode, st
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, st
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;
}
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1773,7 +1773,7 @@ static const struct inode_operations cep
/*
* setattr
*/
-int ceph_setattr(struct dentry *dentry, struct iattr *attr)
+int __ceph_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
struct ceph_inode_info *ci = ceph_inode(inode);
@@ -1975,11 +1975,6 @@ int ceph_setattr(struct dentry *dentry,
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;
@@ -1993,13 +1988,23 @@ int ceph_setattr(struct dentry *dentry,
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);
+
+ if (err >= 0 && (mask & CEPH_SETATTR_SIZE))
+ __ceph_do_pending_vmtruncate(inode);
+
return err;
-out_put:
- ceph_mdsc_put_request(req);
- ceph_free_cap_flush(prealloc_cf);
+}
+
+int ceph_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ int err;
+
+ err = __ceph_setattr(dentry, attr);
+
+ if (err >= 0 && (attr->ia_valid & ATTR_MODE))
+ err = posix_acl_chmod(d_inode(dentry), attr->ia_mode);
+
return err;
}
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -788,6 +788,7 @@ static inline int ceph_do_getattr(struct
return __ceph_do_getattr(inode, NULL, mask, force);
}
extern int ceph_permission(struct inode *inode, int mask);
+extern int __ceph_setattr(struct dentry *dentry, struct iattr *attr);
extern int ceph_setattr(struct dentry *dentry, struct iattr *attr);
extern int ceph_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat);
Patches currently in stable-queue which might be from zyan@xxxxxxxxxx are
queue-4.4/ceph-fix-recursion-between-ceph_set_acl-and-__ceph_setattr.patch