path: root/fs/cifs/cifsacl.c

/*
 *   fs/cifs/cifsacl.c
 *
 *   Copyright (C) International Business Machines  Corp., 2007,2008
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   Contains the routines for mapping CIFS/NTFS ACLs
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/keyctl.h>
#include <linux/key-type.h>
#include <keys/user-type.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsacl.h"
#include "cifsproto.h"
#include "cifs_debug.h"

/* security id for everyone/world system group */
static const struct cifs_sid sid_everyone = {
	1, 1, {0, 0, 0, 0, 0, 1}, {0} };
/* security id for Authenticated Users system group */
static const struct cifs_sid sid_authusers = {
	1, 1, {0, 0, 0, 0, 0, 5}, {__constant_cpu_to_le32(11)} };
/* group users */
static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} };

const struct cred *root_cred;

static void
shrink_idmap_tree(struct rb_root *root, int nr_to_scan, int *nr_rem,
			int *nr_del)
{
	struct rb_node *node;
	struct rb_node *tmp;
	struct cifs_sid_id *psidid;

	node = rb_first(root);
	while (node) {
		tmp = node;
		node = rb_next(tmp);
		psidid = rb_entry(tmp, struct cifs_sid_id, rbnode);
		if (nr_to_scan == 0 || *nr_del == nr_to_scan)
			++(*nr_rem);
		else {
			if (time_after(jiffies, psidid->time + SID_MAP_EXPIRE)
						&& psidid->refcount == 0) {
				rb_erase(tmp, root);
				++(*nr_del);
			} else
				++(*nr_rem);
		}
	}
}

/*
 * Run idmap cache shrinker.
 */
static int
cifs_idmap_shrinker(struct shrinker *shrink, struct shrink_control *sc)
{
	int nr_to_scan = sc->nr_to_scan;
	int nr_del = 0;
	int nr_rem = 0;
	struct rb_root *root;

	root = &uidtree;
	spin_lock(&siduidlock);
	shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del);
	spin_unlock(&siduidlock);

	root = &gidtree;
	spin_lock(&sidgidlock);
	shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del);
	spin_unlock(&sidgidlock);

	return nr_rem;
}

static struct shrinker cifs_shrinker = {
	.shrink = cifs_idmap_shrinker,
	.seeks = DEFAULT_SEEKS,
};

static int
cifs_idmap_key_instantiate(struct key *key, const void *data, size_t datalen)
{
	char *payload;

	payload = kmalloc(datalen, GFP_KERNEL);
	if (!payload)
		return -ENOMEM;

	memcpy(payload, data, datalen);
	key->payload.data = payload;
	return 0;