[linux.git] / fs / ubifs / xattr.c

/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program 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 General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Authors: Artem Bityutskiy (Битюцкий Артём)
 *          Adrian Hunter
 */

/*
 * This file implements UBIFS extended attributes support.
 *
 * Extended attributes are implemented as regular inodes with attached data,
 * which limits extended attribute size to UBIFS block size (4KiB). Names of
 * extended attributes are described by extended attribute entries (xentries),
 * which are almost identical to directory entries, but have different key type.
 *
 * In other words, the situation with extended attributes is very similar to
 * directories. Indeed, any inode (but of course not xattr inodes) may have a
 * number of associated xentries, just like directory inodes have associated
 * directory entries. Extended attribute entries store the name of the extended
 * attribute, the host inode number, and the extended attribute inode number.
 * Similarly, direntries store the name, the parent and the target inode
 * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
 * extended attributes.
 *
 * The number of extended attributes is not limited, but there is Linux
 * limitation on the maximum possible size of the list of all extended
 * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
 * the sum of all extended attribute names of the inode does not exceed that
 * limit.
 *
 * Extended attributes are synchronous, which means they are written to the
 * flash media synchronously and there is no write-back for extended attribute
 * inodes. The extended attribute values are not stored in compressed form on
 * the media.
 *
 * Since extended attributes are represented by regular inodes, they are cached
 * in the VFS inode cache. The xentries are cached in the LNC cache (see
 * tnc.c).
 *
 * ACL support is not implemented.
 */

#include "ubifs.h"
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/xattr.h>

/*
 * Limit the number of extended attributes per inode so that the total size
 * (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
 */
#define MAX_XATTRS_PER_INODE 65535

/*
 * Extended attribute type constants.
 *
 * USER_XATTR: user extended attribute ("user.*")
 * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
 * SECURITY_XATTR: security extended attribute ("security.*")
 */
enum {
	USER_XATTR,
	TRUSTED_XATTR,
	SECURITY_XATTR,
};

static const struct inode_operations empty_iops;
static const struct file_operations empty_fops;

/**
 * create_xattr - create an extended attribute.
 * @c: UBIFS file-system description object
 * @host: host inode
 * @nm: extended attribute name
 * @value: extended attribute value
 * @size: size of extended attribute value
 *
 * This is a helper function which creates an extended attribute of name @nm
 * and value @value for inode @host. The host inode is also updated on flash
 * because the ctime and extended attribute accounting data changes. This
 * function returns zero in case of success and a negative error code in case
 * of failure.
 */
static int create_xattr(struct ubifs_info *c, struct inode *host,
			const struct qstr *nm, const void *value, int size)
{
	int err, names_len;
	struct inode *inode;
	struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
				.new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
				.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };

	if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE) {
		ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more",
			  host->i_ino, host_ui->xattr_cnt);
		return -ENOSPC;
	}
	/*
	 * Linux limits the maximum size of the extended attribute names list
	 * to %XATTR_LIST_MAX. This means we should not allow creating more
	 * extended attributes if the name list becomes larger. This limitation
	 * is artificial for UBIFS, though.
	 */
	names_len = host_ui->xattr_names + host_ui->xattr_cnt + nm->len + 1;
	if (names_len > XATTR_LIST_MAX) {
		ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
			  host->i_ino, names_len, XATTR_LIST_MAX);
		return -ENOSPC;
	}

	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO);
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_budg;
	}

	/* Re-define all operations to be "nothing" */
	inode->i_mapping->a_ops = &empty_aops;
	inode->i_op = &empty_iops;
	inode->i_fop = &empty_fops;

	inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME | S_NOQUOTA;
	ui = ubifs_inode(inode);
	ui->xattr = 1;
	ui->flags |= UBIFS_XATTR_FL;
	ui->data = kmemdup(value, size, GFP_NOFS);
	if (!ui->data) {
		err = -ENOMEM;
		goto out_free;
	}
	inode->i_size = ui->ui_size = size;
	ui->data_len = size;

	mutex_lock(&host_ui->ui_mutex);
	host->i_ctime = ubifs_current_time(host);
	host_ui->xattr_cnt += 1;
	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size += CALC_XATTR_BYTES(size);
	host_ui->xattr_names += nm->len;

	err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	insert_inode_hash(inode);
	iput(inode);
	return 0;

out_cancel:
	host_ui->xattr_cnt -= 1;
	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	mutex_unlock(&host_ui->ui_mutex);
out_free:
	make_bad_inode(inode);
	iput(inode);
out_budg:
	ubifs_release_budget(c, &req);
	return err;
}

/**
 * change_xattr - change an extended attribute.
 * @c: UBIFS file-system description object
 * @host: host inode
 * @inode: extended attribute inode
 * @value: extended attribute value
 * @size: size of extended attribute value
 *
 * This helper function changes the value of extended attribute @inode with new
 * data from @value. Returns zero in case of success and a negative error code
 * in case of failure.
 */
static int change_xattr(struct ubifs_info *c, struct inode *host,
			struct inode *inode, const void *value, int size)
{
	int err;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_inode *ui = ubifs_inode(inode);
	void *buf = NULL;
	struct ubifs_budget_req req = { .dirtied_ino = 2,
		.dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };

	ubifs_assert(ui->data_len == inode->i_size);
	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	buf = kmemdup(value, size, GFP_NOFS);
	if (!buf) {
		err = -ENOMEM;
		goto out_free;
	}
	mutex_lock(&ui->ui_mutex);
	kfree(ui->data);
	ui->data = buf;
	inode->i_size = ui->ui_size = size;
	ui->data_len = size;
	mutex_unlock(&ui->ui_mutex);

	mutex_lock(&host_ui->ui_mutex);
	host->i_ctime = ubifs_current_time(host);
	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	host_ui->xattr_size += CALC_XATTR_BYTES(size);

	/*
	 * It is important to write the host inode after the xattr inode
	 * because if the host inode gets synchronized (via 'fsync()'), then
	 * the extended attribute inode gets synchronized, because it goes
	 * before the host inode in the write-buffer.
	 */
	err = ubifs_jnl_change_xattr(c, inode, host);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	return 0;

out_cancel:
	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
	mutex_unlock(&host_ui->ui_mutex);
	make_bad_inode(inode);
out_free:
	ubifs_release_budget(c, &req);
	return err;
}

static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
{
	struct inode *inode;

	inode = ubifs_iget(c->vfs_sb, inum);
	if (IS_ERR(inode)) {
		ubifs_err(c, "dead extended attribute entry, error %d",
			  (int)PTR_ERR(inode));
		return inode;
	}
	if (ubifs_inode(inode)->xattr)
		return inode;
	ubifs_err(c, "corrupt extended attribute entry");
	iput(inode);
	return ERR_PTR(-EINVAL);
}

static int __ubifs_setxattr(struct inode *host, const char *name,
			    const void *value, size_t size, int flags)
{
	struct inode *inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct qstr nm = QSTR_INIT(name, strlen(name));
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	ubifs_assert(inode_is_locked(host));

	if (size > UBIFS_MAX_INO_DATA)
		return -ERANGE;

	if (nm.len > UBIFS_MAX_NLEN)
		return -ENAMETOOLONG;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	/*
	 * The extended attribute entries are stored in LNC, so multiple
	 * look-ups do not involve reading the flash.
	 */
	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err != -ENOENT)
			goto out_free;

		if (flags & XATTR_REPLACE)
			/* We are asked not to create the xattr */
			err = -ENODATA;
		else
			err = create_xattr(c, host, &nm, value, size);
		goto out_free;
	}

	if (flags & XATTR_CREATE) {
		/* We are asked not to replace the xattr */
		err = -EEXIST;
		goto out_free;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_free;
	}

	err = change_xattr(c, host, inode, value, size);
	iput(inode);

out_free:
	kfree(xent);
	return err;
}

static ssize_t __ubifs_getxattr(struct inode *host, const char *name,
				void *buf, size_t size)
{
	struct inode *inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct qstr nm = QSTR_INIT(name, strlen(name));
	struct ubifs_inode *ui;
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	if (nm.len > UBIFS_MAX_NLEN)
		return -ENAMETOOLONG;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err == -ENOENT)
			err = -ENODATA;
		goto out_unlock;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_unlock;
	}

	ui = ubifs_inode(inode);
	ubifs_assert(inode->i_size == ui->data_len);
	ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);

	mutex_lock(&ui->ui_mutex);
	if (buf) {
		/* If @buf is %NULL we are supposed to return the length */
		if (ui->data_len > size) {
			ubifs_err(c, "buffer size %zd, xattr len %d",
				  size, ui->data_len);
			err = -ERANGE;
			goto out_iput;
		}

		memcpy(buf, ui->data, ui->data_len);
	}
	err = ui->data_len;

out_iput:
	mutex_unlock(&ui->ui_mutex);
	iput(inode);
out_unlock:
	kfree(xent);
	return err;
}

ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	union ubifs_key key;
	struct inode *host = d_inode(dentry);
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_dent_node *xent, *pxent = NULL;
	int err, len, written = 0;
	struct qstr nm = { .name = NULL };

	dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
		dentry, size);

	len = host_ui->xattr_names + host_ui->xattr_cnt;
	if (!buffer)
		/*
		 * We should return the minimum buffer size which will fit a
		 * null-terminated list of all the extended attribute names.
		 */
		return len;

	if (len > size)
		return -ERANGE;

	lowest_xent_key(c, &key, host->i_ino);
	while (1) {
		xent = ubifs_tnc_next_ent(c, &key, &nm);
		if (IS_ERR(xent)) {
			err = PTR_ERR(xent);
			break;
		}

		nm.name = xent->name;
		nm.len = le16_to_cpu(xent->nlen);

		/* Show trusted namespace only for "power" users */
		if (strncmp(xent->name, XATTR_TRUSTED_PREFIX,
			    XATTR_TRUSTED_PREFIX_LEN) ||
		    capable(CAP_SYS_ADMIN)) {
			memcpy(buffer + written, nm.name, nm.len + 1);
			written += nm.len + 1;
		}

		kfree(pxent);
		pxent = xent;
		key_read(c, &xent->key, &key);
	}

	kfree(pxent);
	if (err != -ENOENT) {
		ubifs_err(c, "cannot find next direntry, error %d", err);
		return err;
	}

	ubifs_assert(written <= size);
	return written;
}

static int remove_xattr(struct ubifs_info *c, struct inode *host,
			struct inode *inode, const struct qstr *nm)
{
	int err;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_inode *ui = ubifs_inode(inode);
	struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
				.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };

	ubifs_assert(ui->data_len == inode->i_size);

	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	mutex_lock(&host_ui->ui_mutex);
	host->i_ctime = ubifs_current_time(host);
	host_ui->xattr_cnt -= 1;
	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	host_ui->xattr_names -= nm->len;

	err = ubifs_jnl_delete_xattr(c, host, inode, nm);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	return 0;

out_cancel:
	host_ui->xattr_cnt += 1;
	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
	mutex_unlock(&host_ui->ui_mutex);
	ubifs_release_budget(c, &req);
	make_bad_inode(inode);
	return err;
}

static int __ubifs_removexattr(struct inode *host, const char *name)
{
	struct inode *inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct qstr nm = QSTR_INIT(name, strlen(name));
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	ubifs_assert(inode_is_locked(host));

	if (nm.len > UBIFS_MAX_NLEN)
		return -ENAMETOOLONG;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err == -ENOENT)
			err = -ENODATA;
		goto out_free;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_free;
	}

	ubifs_assert(inode->i_nlink == 1);
	clear_nlink(inode);
	err = remove_xattr(c, host, inode, &nm);
	if (err)
		set_nlink(inode, 1);

	/* If @i_nlink is 0, 'iput()' will delete the inode */
	iput(inode);

out_free:
	kfree(xent);
	return err;
}

static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
		      void *fs_info)
{
	const struct xattr *xattr;
	char *name;
	int err = 0;

	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
			       strlen(xattr->name) + 1, GFP_NOFS);
		if (!name) {
			err = -ENOMEM;
			break;
		}
		strcpy(name, XATTR_SECURITY_PREFIX);
		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
		err = __ubifs_setxattr(inode, name, xattr->value, xattr->value_len, 0);
		kfree(name);
		if (err < 0)
			break;
	}

	return err;
}

int ubifs_init_security(struct inode *dentry, struct inode *inode,
			const struct qstr *qstr)
{
	int err;

	err = security_inode_init_security(inode, dentry, qstr,
					   &init_xattrs, 0);
	if (err) {
		struct ubifs_info *c = dentry->i_sb->s_fs_info;
		ubifs_err(c, "cannot initialize security for inode %lu, error %d",
			  inode->i_ino, err);
	}
	return err;
}

static int ubifs_xattr_get(const struct xattr_handler *handler,
			   struct dentry *dentry, struct inode *inode,
			   const char *name, void *buffer, size_t size)
{
	dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
		inode->i_ino, dentry, size);

	return  __ubifs_getxattr(inode, name, buffer, size);
}

static int ubifs_xattr_set(const struct xattr_handler *handler,
			   struct dentry *dentry, struct inode *inode,
			   const char *name, const void *value,
			   size_t size, int flags)
{
	dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
		name, inode->i_ino, dentry, size);

	if (value)
		return __ubifs_setxattr(inode, name, value, size, flags);
	else
		return __ubifs_removexattr(inode, name);
}

static const struct xattr_handler ubifs_user_xattr_handler = {
	.prefix = XATTR_USER_PREFIX,
	.get = ubifs_xattr_get,
	.set = ubifs_xattr_set,
};

static const struct xattr_handler ubifs_trusted_xattr_handler = {
	.prefix = XATTR_TRUSTED_PREFIX,
	.get = ubifs_xattr_get,
	.set = ubifs_xattr_set,
};

static const struct xattr_handler ubifs_security_xattr_handler = {
	.prefix = XATTR_SECURITY_PREFIX,
	.get = ubifs_xattr_get,
	.set = ubifs_xattr_set,
};

const struct xattr_handler *ubifs_xattr_handlers[] = {
	&ubifs_user_xattr_handler,
	&ubifs_trusted_xattr_handler,
	&ubifs_security_xattr_handler,
	NULL
};
Commit	Line	Data
1e51764a AB	1	/*
	2	* This file is part of UBIFS.
	3	*
	4	* Copyright (C) 2006-2008 Nokia Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License version 2 as published by
	8	* the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc., 51
	17	* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	18	*
	19	* Authors: Artem Bityutskiy (Битюцкий Артём)
	20	* Adrian Hunter
	21	*/
	22
	23	/*
	24	* This file implements UBIFS extended attributes support.
	25	*
	26	* Extended attributes are implemented as regular inodes with attached data,
	27	* which limits extended attribute size to UBIFS block size (4KiB). Names of
	28	* extended attributes are described by extended attribute entries (xentries),
	29	* which are almost identical to directory entries, but have different key type.
	30	*
	31	* In other words, the situation with extended attributes is very similar to
	32	* directories. Indeed, any inode (but of course not xattr inodes) may have a
	33	* number of associated xentries, just like directory inodes have associated
	34	* directory entries. Extended attribute entries store the name of the extended
	35	* attribute, the host inode number, and the extended attribute inode number.
	36	* Similarly, direntries store the name, the parent and the target inode
	37	* numbers. Thus, most of the common UBIFS mechanisms may be re-used for
	38	* extended attributes.
	39	*
	40	* The number of extended attributes is not limited, but there is Linux
	41	* limitation on the maximum possible size of the list of all extended
	42	* attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
	43	* the sum of all extended attribute names of the inode does not exceed that
	44	* limit.
	45	*
	46	* Extended attributes are synchronous, which means they are written to the
	47	* flash media synchronously and there is no write-back for extended attribute
	48	* inodes. The extended attribute values are not stored in compressed form on
	49	* the media.
	50	*
	51	* Since extended attributes are represented by regular inodes, they are cached
	52	* in the VFS inode cache. The xentries are cached in the LNC cache (see
	53	* tnc.c).
	54	*
	55	* ACL support is not implemented.
	56	*/
	57
073aaa1b	58	#include "ubifs.h"
7dcda1c9	59	#include <linux/fs.h>
5a0e3ad6	60	#include <linux/slab.h>
1e51764a	61	#include <linux/xattr.h>
1e51764a AB	62
	63	/*
	64	* Limit the number of extended attributes per inode so that the total size
c78c7e35	65	* (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
1e51764a AB	66	*/
	67	#define MAX_XATTRS_PER_INODE 65535
	68
	69	/*
	70	* Extended attribute type constants.
	71	*
	72	* USER_XATTR: user extended attribute ("user.*")
	73	* TRUSTED_XATTR: trusted extended attribute ("trusted.*)
	74	* SECURITY_XATTR: security extended attribute ("security.*")
	75	*/
	76	enum {
	77	USER_XATTR,
	78	TRUSTED_XATTR,
	79	SECURITY_XATTR,
	80	};
	81
14ffd5d0 SD	82	static const struct inode_operations empty_iops;
14ffd5d0 SD	83	static const struct file_operations empty_fops;
1e51764a AB	84
	85	/**
	86	* create_xattr - create an extended attribute.
	87	* @c: UBIFS file-system description object
	88	* @host: host inode
	89	* @nm: extended attribute name
	90	* @value: extended attribute value
	91	* @size: size of extended attribute value
	92	*
	93	* This is a helper function which creates an extended attribute of name @nm
	94	* and value @value for inode @host. The host inode is also updated on flash
	95	* because the ctime and extended attribute accounting data changes. This
	96	* function returns zero in case of success and a negative error code in case
	97	* of failure.
	98	*/
	99	static int create_xattr(struct ubifs_info c, struct inode host,
	100	const struct qstr nm, const void value, int size)
	101	{
fee1756d	102	int err, names_len;
1e51764a AB	103	struct inode *inode;
	104	struct ubifs_inode ui, host_ui = ubifs_inode(host);
	105	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
5acd6ff8 ZS	106	.new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
5acd6ff8 ZS	107	.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
1e51764a	108
fee1756d	109	if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE) {
235c362b	110	ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more",
fee1756d	111	host->i_ino, host_ui->xattr_cnt);
1e51764a	112	return -ENOSPC;
fee1756d	113	}
1e51764a AB	114	/*
1e51764a AB	115	* Linux limits the maximum size of the extended attribute names list
c78c7e35	116	* to %XATTR_LIST_MAX. This means we should not allow creating more
1e51764a AB	117	* extended attributes if the name list becomes larger. This limitation
	118	* is artificial for UBIFS, though.
	119	*/
fee1756d SN	120	names_len = host_ui->xattr_names + host_ui->xattr_cnt + nm->len + 1;
fee1756d SN	121	if (names_len > XATTR_LIST_MAX) {
235c362b	122	ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
fee1756d	123	host->i_ino, names_len, XATTR_LIST_MAX);
1e51764a	124	return -ENOSPC;
fee1756d	125	}
1e51764a AB	126
	127	err = ubifs_budget_space(c, &req);
	128	if (err)
	129	return err;
	130
	131	inode = ubifs_new_inode(c, host, S_IFREG \| S_IRWXUGO);
	132	if (IS_ERR(inode)) {
	133	err = PTR_ERR(inode);
	134	goto out_budg;
	135	}
	136
1e51764a	137	/* Re-define all operations to be "nothing" */
7dcda1c9	138	inode->i_mapping->a_ops = &empty_aops;
14ffd5d0 SD	139	inode->i_op = &empty_iops;
14ffd5d0 SD	140	inode->i_fop = &empty_fops;
1e51764a AB	141
	142	inode->i_flags \|= S_SYNC \| S_NOATIME \| S_NOCMTIME \| S_NOQUOTA;
	143	ui = ubifs_inode(inode);
	144	ui->xattr = 1;
	145	ui->flags \|= UBIFS_XATTR_FL;
eaecf43a	146	ui->data = kmemdup(value, size, GFP_NOFS);
1e51764a AB	147	if (!ui->data) {
1e51764a AB	148	err = -ENOMEM;
c78c7e35	149	goto out_free;
1e51764a	150	}
c78c7e35 AB	151	inode->i_size = ui->ui_size = size;
	152	ui->data_len = size;
	153
	154	mutex_lock(&host_ui->ui_mutex);
1e51764a AB	155	host->i_ctime = ubifs_current_time(host);
	156	host_ui->xattr_cnt += 1;
	157	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	158	host_ui->xattr_size += CALC_XATTR_BYTES(size);
	159	host_ui->xattr_names += nm->len;
	160
1e51764a AB	161	err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
	162	if (err)
	163	goto out_cancel;
	164	mutex_unlock(&host_ui->ui_mutex);
	165
	166	ubifs_release_budget(c, &req);
	167	insert_inode_hash(inode);
	168	iput(inode);
	169	return 0;
	170
	171	out_cancel:
	172	host_ui->xattr_cnt -= 1;
	173	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	174	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
1e51764a	175	mutex_unlock(&host_ui->ui_mutex);
c78c7e35	176	out_free:
1e51764a AB	177	make_bad_inode(inode);
	178	iput(inode);
	179	out_budg:
	180	ubifs_release_budget(c, &req);
	181	return err;
	182	}
	183
	184	/**
	185	* change_xattr - change an extended attribute.
	186	* @c: UBIFS file-system description object
	187	* @host: host inode
	188	* @inode: extended attribute inode
	189	* @value: extended attribute value
	190	* @size: size of extended attribute value
	191	*
	192	* This helper function changes the value of extended attribute @inode with new
	193	* data from @value. Returns zero in case of success and a negative error code
	194	* in case of failure.
	195	*/
	196	static int change_xattr(struct ubifs_info c, struct inode host,
	197	struct inode inode, const void value, int size)
	198	{
	199	int err;
	200	struct ubifs_inode *host_ui = ubifs_inode(host);
	201	struct ubifs_inode *ui = ubifs_inode(inode);
ab92a20b	202	void *buf = NULL;
1e51764a	203	struct ubifs_budget_req req = { .dirtied_ino = 2,
5acd6ff8	204	.dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
1e51764a AB	205
	206	ubifs_assert(ui->data_len == inode->i_size);
	207	err = ubifs_budget_space(c, &req);
	208	if (err)
	209	return err;
	210
ab92a20b DY	211	buf = kmemdup(value, size, GFP_NOFS);
ab92a20b DY	212	if (!buf) {
1e51764a	213	err = -ENOMEM;
c78c7e35	214	goto out_free;
1e51764a	215	}
ab92a20b DY	216	mutex_lock(&ui->ui_mutex);
	217	kfree(ui->data);
	218	ui->data = buf;
1e51764a AB	219	inode->i_size = ui->ui_size = size;
1e51764a AB	220	ui->data_len = size;
ab92a20b	221	mutex_unlock(&ui->ui_mutex);
1e51764a	222
c78c7e35 AB	223	mutex_lock(&host_ui->ui_mutex);
	224	host->i_ctime = ubifs_current_time(host);
	225	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	226	host_ui->xattr_size += CALC_XATTR_BYTES(size);
	227
1e51764a AB	228	/*
	229	* It is important to write the host inode after the xattr inode
	230	* because if the host inode gets synchronized (via 'fsync()'), then
	231	* the extended attribute inode gets synchronized, because it goes
	232	* before the host inode in the write-buffer.
	233	*/
	234	err = ubifs_jnl_change_xattr(c, inode, host);
	235	if (err)
	236	goto out_cancel;
	237	mutex_unlock(&host_ui->ui_mutex);
	238
	239	ubifs_release_budget(c, &req);
	240	return 0;
	241
	242	out_cancel:
	243	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	244	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
1e51764a	245	mutex_unlock(&host_ui->ui_mutex);
c78c7e35 AB	246	make_bad_inode(inode);
c78c7e35 AB	247	out_free:
1e51764a AB	248	ubifs_release_budget(c, &req);
	249	return err;
	250	}
	251
1e51764a AB	252	static struct inode iget_xattr(struct ubifs_info c, ino_t inum)
	253	{
	254	struct inode *inode;
	255
	256	inode = ubifs_iget(c->vfs_sb, inum);
	257	if (IS_ERR(inode)) {
235c362b	258	ubifs_err(c, "dead extended attribute entry, error %d",
1e51764a AB	259	(int)PTR_ERR(inode));
	260	return inode;
	261	}
	262	if (ubifs_inode(inode)->xattr)
	263	return inode;
235c362b	264	ubifs_err(c, "corrupt extended attribute entry");
1e51764a AB	265	iput(inode);
	266	return ERR_PTR(-EINVAL);
	267	}
	268
2b88fc21 AG	269	static int __ubifs_setxattr(struct inode host, const char name,
2b88fc21 AG	270	const void *value, size_t size, int flags)
1e51764a	271	{
895d9db2	272	struct inode *inode;
1e51764a	273	struct ubifs_info *c = host->i_sb->s_fs_info;
26fe5750	274	struct qstr nm = QSTR_INIT(name, strlen(name));
1e51764a AB	275	struct ubifs_dent_node *xent;
1e51764a AB	276	union ubifs_key key;
2b88fc21	277	int err;
1e51764a	278
5955102c	279	ubifs_assert(inode_is_locked(host));
1e51764a AB	280
	281	if (size > UBIFS_MAX_INO_DATA)
	282	return -ERANGE;
	283
2b88fc21 AG	284	if (nm.len > UBIFS_MAX_NLEN)
2b88fc21 AG	285	return -ENAMETOOLONG;
1e51764a AB	286
	287	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	288	if (!xent)
	289	return -ENOMEM;
	290
	291	/*
	292	* The extended attribute entries are stored in LNC, so multiple
	293	* look-ups do not involve reading the flash.
	294	*/
	295	xent_key_init(c, &key, host->i_ino, &nm);
	296	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	297	if (err) {
	298	if (err != -ENOENT)
	299	goto out_free;
	300
	301	if (flags & XATTR_REPLACE)
	302	/* We are asked not to create the xattr */
	303	err = -ENODATA;
	304	else
	305	err = create_xattr(c, host, &nm, value, size);
	306	goto out_free;
	307	}
	308
	309	if (flags & XATTR_CREATE) {
	310	/* We are asked not to replace the xattr */
	311	err = -EEXIST;
	312	goto out_free;
	313	}
	314
	315	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	316	if (IS_ERR(inode)) {
	317	err = PTR_ERR(inode);
	318	goto out_free;
	319	}
	320
	321	err = change_xattr(c, host, inode, value, size);
	322	iput(inode);
	323
	324	out_free:
	325	kfree(xent);
	326	return err;
	327	}
	328
2b88fc21 AG	329	static ssize_t __ubifs_getxattr(struct inode host, const char name,
2b88fc21 AG	330	void *buf, size_t size)
1e51764a	331	{
ce23e640	332	struct inode *inode;
1e51764a	333	struct ubifs_info *c = host->i_sb->s_fs_info;
26fe5750	334	struct qstr nm = QSTR_INIT(name, strlen(name));
1e51764a AB	335	struct ubifs_inode *ui;
	336	struct ubifs_dent_node *xent;
	337	union ubifs_key key;
	338	int err;
	339
2b88fc21 AG	340	if (nm.len > UBIFS_MAX_NLEN)
2b88fc21 AG	341	return -ENAMETOOLONG;
1e51764a AB	342
	343	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	344	if (!xent)
	345	return -ENOMEM;
	346
1e51764a AB	347	xent_key_init(c, &key, host->i_ino, &nm);
	348	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	349	if (err) {
	350	if (err == -ENOENT)
	351	err = -ENODATA;
	352	goto out_unlock;
	353	}
	354
	355	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	356	if (IS_ERR(inode)) {
	357	err = PTR_ERR(inode);
	358	goto out_unlock;
	359	}
	360
	361	ui = ubifs_inode(inode);
	362	ubifs_assert(inode->i_size == ui->data_len);
	363	ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);
	364
ab92a20b	365	mutex_lock(&ui->ui_mutex);
1e51764a AB	366	if (buf) {
	367	/* If @buf is %NULL we are supposed to return the length */
	368	if (ui->data_len > size) {
235c362b	369	ubifs_err(c, "buffer size %zd, xattr len %d",
a6aae4dd	370	size, ui->data_len);
1e51764a AB	371	err = -ERANGE;
	372	goto out_iput;
	373	}
	374
	375	memcpy(buf, ui->data, ui->data_len);
	376	}
	377	err = ui->data_len;
	378
	379	out_iput:
ab92a20b	380	mutex_unlock(&ui->ui_mutex);
1e51764a AB	381	iput(inode);
1e51764a AB	382	out_unlock:
1e51764a AB	383	kfree(xent);
	384	return err;
	385	}
	386
	387	ssize_t ubifs_listxattr(struct dentry dentry, char buffer, size_t size)
	388	{
	389	union ubifs_key key;
2b0143b5	390	struct inode *host = d_inode(dentry);
1e51764a AB	391	struct ubifs_info *c = host->i_sb->s_fs_info;
	392	struct ubifs_inode *host_ui = ubifs_inode(host);
	393	struct ubifs_dent_node xent, pxent = NULL;
	394	int err, len, written = 0;
	395	struct qstr nm = { .name = NULL };
	396
4cb2a01d AV	397	dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
4cb2a01d AV	398	dentry, size);
1e51764a AB	399
	400	len = host_ui->xattr_names + host_ui->xattr_cnt;
	401	if (!buffer)
	402	/*
	403	* We should return the minimum buffer size which will fit a
	404	* null-terminated list of all the extended attribute names.
	405	*/
	406	return len;
	407
	408	if (len > size)
	409	return -ERANGE;
	410
	411	lowest_xent_key(c, &key, host->i_ino);
1e51764a	412	while (1) {
1e51764a	413	xent = ubifs_tnc_next_ent(c, &key, &nm);
8d47aef4	414	if (IS_ERR(xent)) {
1e51764a AB	415	err = PTR_ERR(xent);
	416	break;
	417	}
	418
	419	nm.name = xent->name;
	420	nm.len = le16_to_cpu(xent->nlen);
	421
1e51764a	422	/* Show trusted namespace only for "power" users */
2b88fc21 AG	423	if (strncmp(xent->name, XATTR_TRUSTED_PREFIX,
	424	XATTR_TRUSTED_PREFIX_LEN) \|\|
	425	capable(CAP_SYS_ADMIN)) {
1e51764a AB	426	memcpy(buffer + written, nm.name, nm.len + 1);
	427	written += nm.len + 1;
	428	}
	429
	430	kfree(pxent);
	431	pxent = xent;
	432	key_read(c, &xent->key, &key);
	433	}
1e51764a AB	434
	435	kfree(pxent);
	436	if (err != -ENOENT) {
235c362b	437	ubifs_err(c, "cannot find next direntry, error %d", err);
1e51764a AB	438	return err;
	439	}
	440
	441	ubifs_assert(written <= size);
	442	return written;
	443	}
	444
	445	static int remove_xattr(struct ubifs_info c, struct inode host,
	446	struct inode inode, const struct qstr nm)
	447	{
	448	int err;
	449	struct ubifs_inode *host_ui = ubifs_inode(host);
	450	struct ubifs_inode *ui = ubifs_inode(inode);
5acd6ff8 ZS	451	struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
5acd6ff8 ZS	452	.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
1e51764a AB	453
	454	ubifs_assert(ui->data_len == inode->i_size);
	455
	456	err = ubifs_budget_space(c, &req);
	457	if (err)
	458	return err;
	459
	460	mutex_lock(&host_ui->ui_mutex);
	461	host->i_ctime = ubifs_current_time(host);
	462	host_ui->xattr_cnt -= 1;
	463	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
	464	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	465	host_ui->xattr_names -= nm->len;
	466
	467	err = ubifs_jnl_delete_xattr(c, host, inode, nm);
	468	if (err)
	469	goto out_cancel;
	470	mutex_unlock(&host_ui->ui_mutex);
	471
	472	ubifs_release_budget(c, &req);
	473	return 0;
	474
	475	out_cancel:
	476	host_ui->xattr_cnt += 1;
	477	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
	478	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
	479	mutex_unlock(&host_ui->ui_mutex);
	480	ubifs_release_budget(c, &req);
	481	make_bad_inode(inode);
	482	return err;
	483	}
	484
2b88fc21	485	static int __ubifs_removexattr(struct inode host, const char name)
1e51764a	486	{
2b88fc21	487	struct inode *inode;
1e51764a	488	struct ubifs_info *c = host->i_sb->s_fs_info;
26fe5750	489	struct qstr nm = QSTR_INIT(name, strlen(name));
1e51764a AB	490	struct ubifs_dent_node *xent;
	491	union ubifs_key key;
	492	int err;
	493
5955102c	494	ubifs_assert(inode_is_locked(host));
1e51764a	495
2b88fc21 AG	496	if (nm.len > UBIFS_MAX_NLEN)
2b88fc21 AG	497	return -ENAMETOOLONG;
1e51764a AB	498
	499	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	500	if (!xent)
	501	return -ENOMEM;
	502
	503	xent_key_init(c, &key, host->i_ino, &nm);
	504	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	505	if (err) {
	506	if (err == -ENOENT)
	507	err = -ENODATA;
	508	goto out_free;
	509	}
	510
	511	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	512	if (IS_ERR(inode)) {
	513	err = PTR_ERR(inode);
	514	goto out_free;
	515	}
	516
	517	ubifs_assert(inode->i_nlink == 1);
6d6b77f1	518	clear_nlink(inode);
1e51764a AB	519	err = remove_xattr(c, host, inode, &nm);
1e51764a AB	520	if (err)
bfe86848	521	set_nlink(inode, 1);
1e51764a AB	522
	523	/* If @i_nlink is 0, 'iput()' will delete the inode */
	524	iput(inode);
	525
	526	out_free:
	527	kfree(xent);
	528	return err;
	529	}
d7f0b70d	530
d7f0b70d SN	531	static int init_xattrs(struct inode inode, const struct xattr xattr_array,
	532	void *fs_info)
	533	{
	534	const struct xattr *xattr;
	535	char *name;
	536	int err = 0;
	537
	538	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
	539	name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
	540	strlen(xattr->name) + 1, GFP_NOFS);
	541	if (!name) {
	542	err = -ENOMEM;
	543	break;
	544	}
	545	strcpy(name, XATTR_SECURITY_PREFIX);
	546	strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
2b88fc21	547	err = __ubifs_setxattr(inode, name, xattr->value, xattr->value_len, 0);
d7f0b70d SN	548	kfree(name);
	549	if (err < 0)
	550	break;
	551	}
	552
	553	return err;
	554	}
	555
	556	int ubifs_init_security(struct inode dentry, struct inode inode,
	557	const struct qstr *qstr)
	558	{
	559	int err;
	560
d7f0b70d SN	561	err = security_inode_init_security(inode, dentry, qstr,
d7f0b70d SN	562	&init_xattrs, 0);
235c362b SY	563	if (err) {
	564	struct ubifs_info *c = dentry->i_sb->s_fs_info;
	565	ubifs_err(c, "cannot initialize security for inode %lu, error %d",
fee1756d	566	inode->i_ino, err);
235c362b	567	}
d7f0b70d SN	568	return err;
d7f0b70d SN	569	}
2b88fc21 AG	570
	571	static int ubifs_xattr_get(const struct xattr_handler *handler,
	572	struct dentry dentry, struct inode inode,
	573	const char name, void buffer, size_t size)
	574	{
	575	dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
	576	inode->i_ino, dentry, size);
	577
	578	return __ubifs_getxattr(inode, name, buffer, size);
	579	}
	580
	581	static int ubifs_xattr_set(const struct xattr_handler *handler,
59301226 AV	582	struct dentry dentry, struct inode inode,
	583	const char name, const void value,
	584	size_t size, int flags)
2b88fc21	585	{
2b88fc21 AG	586	dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
	587	name, inode->i_ino, dentry, size);
	588
	589	if (value)
	590	return __ubifs_setxattr(inode, name, value, size, flags);
	591	else
	592	return __ubifs_removexattr(inode, name);
	593	}
	594
dfaf8d2a	595	static const struct xattr_handler ubifs_user_xattr_handler = {
2b88fc21 AG	596	.prefix = XATTR_USER_PREFIX,
	597	.get = ubifs_xattr_get,
	598	.set = ubifs_xattr_set,
	599	};
	600
dfaf8d2a	601	static const struct xattr_handler ubifs_trusted_xattr_handler = {
2b88fc21 AG	602	.prefix = XATTR_TRUSTED_PREFIX,
	603	.get = ubifs_xattr_get,
	604	.set = ubifs_xattr_set,
	605	};
	606
dfaf8d2a	607	static const struct xattr_handler ubifs_security_xattr_handler = {
2b88fc21 AG	608	.prefix = XATTR_SECURITY_PREFIX,
	609	.get = ubifs_xattr_get,
	610	.set = ubifs_xattr_set,
	611	};
	612
	613	const struct xattr_handler *ubifs_xattr_handlers[] = {
	614	&ubifs_user_xattr_handler,
	615	&ubifs_trusted_xattr_handler,
	616	&ubifs_security_xattr_handler,
	617	NULL
	618	};