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ceph: fix recursion between ceph_set_acl() and __ceph_setattr()

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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 <leisurelysw24@gmail.com>
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Tested-by: Luis Henriques <lhenriques@suse.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
[luis: introduce __ceph_setattr() and make ceph_set_acl() call it, as
 suggested by Yan.]
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: “Yan, Zheng” <zyan@redhat.com>
This commit is contained in:
Yan, Zheng 2017-04-19 10:01:48 +08:00 committed by Greg Kroah-Hartman
parent 0e9e19a665
commit 04f522476a
3 changed files with 19 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/ceph/acl.c
View File

@ -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;
}

27
fs/ceph/inode.c
View File

@ -1773,7 +1773,7 @@ static const struct inode_operations ceph_symlink_iops = {
/*
* 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, struct iattr *attr)
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, struct iattr *attr)
ceph_cap_string(dirtied), mask);
ceph_mdsc_put_request(req);
if (mask & CEPH_SETATTR_SIZE)
ceph_free_cap_flush(prealloc_cf);
if (err >= 0 && (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);
}
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;
}

1
fs/ceph/super.h
View File

@ -788,6 +788,7 @@ static inline int ceph_do_getattr(struct inode *inode, int mask, bool force)
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);