[linux-block.git] / fs / squashfs / xattr.c

/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2010
 * Phillip Lougher <phillip@squashfs.org.uk>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2,
 * or (at your option) any later version.
 *
 * 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * xattr.c
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/xattr.h>
#include <linux/slab.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"

static const struct xattr_handler *squashfs_xattr_handler(int);

ssize_t squashfs_listxattr(struct dentry *d, char *buffer,
	size_t buffer_size)
{
	struct inode *inode = d_inode(d);
	struct super_block *sb = inode->i_sb;
	struct squashfs_sb_info *msblk = sb->s_fs_info;
	u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
						 + msblk->xattr_table;
	int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
	int count = squashfs_i(inode)->xattr_count;
	size_t rest = buffer_size;
	int err;

	/* check that the file system has xattrs */
	if (msblk->xattr_id_table == NULL)
		return -EOPNOTSUPP;

	/* loop reading each xattr name */
	while (count--) {
		struct squashfs_xattr_entry entry;
		struct squashfs_xattr_val val;
		const struct xattr_handler *handler;
		int name_size, prefix_size = 0;

		err = squashfs_read_metadata(sb, &entry, &start, &offset,
							sizeof(entry));
		if (err < 0)
			goto failed;

		name_size = le16_to_cpu(entry.size);
		handler = squashfs_xattr_handler(le16_to_cpu(entry.type));
		if (handler)
			prefix_size = handler->list(handler, d, buffer, rest,
						    NULL, name_size);
		if (prefix_size) {
			if (buffer) {
				if (prefix_size + name_size + 1 > rest) {
					err = -ERANGE;
					goto failed;
				}
				buffer += prefix_size;
			}
			err = squashfs_read_metadata(sb, buffer, &start,
				&offset, name_size);
			if (err < 0)
				goto failed;
			if (buffer) {
				buffer[name_size] = '\0';
				buffer += name_size + 1;
			}
			rest -= prefix_size + name_size + 1;
		} else  {
			/* no handler or insuffficient privileges, so skip */
			err = squashfs_read_metadata(sb, NULL, &start,
				&offset, name_size);
			if (err < 0)
				goto failed;
		}


		/* skip remaining xattr entry */
		err = squashfs_read_metadata(sb, &val, &start, &offset,
						sizeof(val));
		if (err < 0)
			goto failed;

		err = squashfs_read_metadata(sb, NULL, &start, &offset,
						le32_to_cpu(val.vsize));
		if (err < 0)
			goto failed;
	}
	err = buffer_size - rest;

failed:
	return err;
}


static int squashfs_xattr_get(struct inode *inode, int name_index,
	const char *name, void *buffer, size_t buffer_size)
{
	struct super_block *sb = inode->i_sb;
	struct squashfs_sb_info *msblk = sb->s_fs_info;
	u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
						 + msblk->xattr_table;
	int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
	int count = squashfs_i(inode)->xattr_count;
	int name_len = strlen(name);
	int err, vsize;
	char *target = kmalloc(name_len, GFP_KERNEL);

	if (target == NULL)
		return  -ENOMEM;

	/* loop reading each xattr name */
	for (; count; count--) {
		struct squashfs_xattr_entry entry;
		struct squashfs_xattr_val val;
		int type, prefix, name_size;

		err = squashfs_read_metadata(sb, &entry, &start, &offset,
							sizeof(entry));
		if (err < 0)
			goto failed;

		name_size = le16_to_cpu(entry.size);
		type = le16_to_cpu(entry.type);
		prefix = type & SQUASHFS_XATTR_PREFIX_MASK;

		if (prefix == name_index && name_size == name_len)
			err = squashfs_read_metadata(sb, target, &start,
						&offset, name_size);
		else
			err = squashfs_read_metadata(sb, NULL, &start,
						&offset, name_size);
		if (err < 0)
			goto failed;

		if (prefix == name_index && name_size == name_len &&
					strncmp(target, name, name_size) == 0) {
			/* found xattr */
			if (type & SQUASHFS_XATTR_VALUE_OOL) {
				__le64 xattr_val;
				u64 xattr;
				/* val is a reference to the real location */
				err = squashfs_read_metadata(sb, &val, &start,
						&offset, sizeof(val));
				if (err < 0)
					goto failed;
				err = squashfs_read_metadata(sb, &xattr_val,
					&start, &offset, sizeof(xattr_val));
				if (err < 0)
					goto failed;
				xattr = le64_to_cpu(xattr_val);
				start = SQUASHFS_XATTR_BLK(xattr) +
							msblk->xattr_table;
				offset = SQUASHFS_XATTR_OFFSET(xattr);
			}
			/* read xattr value */
			err = squashfs_read_metadata(sb, &val, &start, &offset,
							sizeof(val));
			if (err < 0)
				goto failed;

			vsize = le32_to_cpu(val.vsize);
			if (buffer) {
				if (vsize > buffer_size) {
					err = -ERANGE;
					goto failed;
				}
				err = squashfs_read_metadata(sb, buffer, &start,
					 &offset, vsize);
				if (err < 0)
					goto failed;
			}
			break;
		}

		/* no match, skip remaining xattr entry */
		err = squashfs_read_metadata(sb, &val, &start, &offset,
							sizeof(val));
		if (err < 0)
			goto failed;
		err = squashfs_read_metadata(sb, NULL, &start, &offset,
						le32_to_cpu(val.vsize));
		if (err < 0)
			goto failed;
	}
	err = count ? vsize : -ENODATA;

failed:
	kfree(target);
	return err;
}


static size_t squashfs_xattr_handler_list(const struct xattr_handler *handler,
					  struct dentry *d, char *list,
					  size_t list_size, const char *name,
					  size_t name_len)
{
	int len = strlen(handler->prefix);

	if (list && len <= list_size)
		memcpy(list, handler->prefix, len);
	return len;
}

static int squashfs_xattr_handler_get(const struct xattr_handler *handler,
				      struct dentry *d, const char *name,
				      void *buffer, size_t size)
{
	return squashfs_xattr_get(d_inode(d), handler->flags, name,
		buffer, size);
}

/*
 * User namespace support
 */
static const struct xattr_handler squashfs_xattr_user_handler = {
	.prefix	= XATTR_USER_PREFIX,
	.flags	= SQUASHFS_XATTR_USER,
	.list	= squashfs_xattr_handler_list,
	.get	= squashfs_xattr_handler_get
};

/*
 * Trusted namespace support
 */
static size_t squashfs_trusted_xattr_handler_list(const struct xattr_handler *handler,
						  struct dentry *d, char *list,
						  size_t list_size, const char *name,
						  size_t name_len)
{
	if (!capable(CAP_SYS_ADMIN))
		return 0;
	return squashfs_xattr_handler_list(handler, d, list, list_size, name,
					   name_len);
}

static const struct xattr_handler squashfs_xattr_trusted_handler = {
	.prefix	= XATTR_TRUSTED_PREFIX,
	.flags	= SQUASHFS_XATTR_TRUSTED,
	.list	= squashfs_trusted_xattr_handler_list,
	.get	= squashfs_xattr_handler_get
};

/*
 * Security namespace support
 */
static const struct xattr_handler squashfs_xattr_security_handler = {
	.prefix	= XATTR_SECURITY_PREFIX,
	.flags	= SQUASHFS_XATTR_SECURITY,
	.list	= squashfs_xattr_handler_list,
	.get	= squashfs_xattr_handler_get
};

static const struct xattr_handler *squashfs_xattr_handler(int type)
{
	if (type & ~(SQUASHFS_XATTR_PREFIX_MASK | SQUASHFS_XATTR_VALUE_OOL))
		/* ignore unrecognised type */
		return NULL;

	switch (type & SQUASHFS_XATTR_PREFIX_MASK) {
	case SQUASHFS_XATTR_USER:
		return &squashfs_xattr_user_handler;
	case SQUASHFS_XATTR_TRUSTED:
		return &squashfs_xattr_trusted_handler;
	case SQUASHFS_XATTR_SECURITY:
		return &squashfs_xattr_security_handler;
	default:
		/* ignore unrecognised type */
		return NULL;
	}
}

const struct xattr_handler *squashfs_xattr_handlers[] = {
	&squashfs_xattr_user_handler,
	&squashfs_xattr_trusted_handler,
	&squashfs_xattr_security_handler,
	NULL
};
Commit	Line	Data
f41d207c PL	1	/*
	2	* Squashfs - a compressed read only filesystem for Linux
	3	*
	4	* Copyright (c) 2010
d7f2ff67	5	* Phillip Lougher <phillip@squashfs.org.uk>
f41d207c PL	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version 2,
	10	* or (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	20	*
4690148f	21	* xattr.c
f41d207c PL	22	*/
	23
	24	#include <linux/init.h>
	25	#include <linux/module.h>
	26	#include <linux/string.h>
	27	#include <linux/fs.h>
	28	#include <linux/vfs.h>
	29	#include <linux/xattr.h>
	30	#include <linux/slab.h>
	31
	32	#include "squashfs_fs.h"
	33	#include "squashfs_fs_sb.h"
	34	#include "squashfs_fs_i.h"
	35	#include "squashfs.h"
	36
f6db25a8	37	static const struct xattr_handler *squashfs_xattr_handler(int);
f41d207c PL	38
	39	ssize_t squashfs_listxattr(struct dentry d, char buffer,
	40	size_t buffer_size)
	41	{
2b0143b5	42	struct inode *inode = d_inode(d);
f41d207c PL	43	struct super_block *sb = inode->i_sb;
	44	struct squashfs_sb_info *msblk = sb->s_fs_info;
	45	u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
	46	+ msblk->xattr_table;
	47	int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
	48	int count = squashfs_i(inode)->xattr_count;
	49	size_t rest = buffer_size;
	50	int err;
	51
	52	/* check that the file system has xattrs */
	53	if (msblk->xattr_id_table == NULL)
	54	return -EOPNOTSUPP;
	55
	56	/* loop reading each xattr name */
	57	while (count--) {
	58	struct squashfs_xattr_entry entry;
	59	struct squashfs_xattr_val val;
f6db25a8	60	const struct xattr_handler *handler;
f41d207c PL	61	int name_size, prefix_size = 0;
	62
	63	err = squashfs_read_metadata(sb, &entry, &start, &offset,
	64	sizeof(entry));
	65	if (err < 0)
	66	goto failed;
	67
	68	name_size = le16_to_cpu(entry.size);
	69	handler = squashfs_xattr_handler(le16_to_cpu(entry.type));
	70	if (handler)
d9a82a04 AG	71	prefix_size = handler->list(handler, d, buffer, rest,
d9a82a04 AG	72	NULL, name_size);
f41d207c PL	73	if (prefix_size) {
	74	if (buffer) {
	75	if (prefix_size + name_size + 1 > rest) {
	76	err = -ERANGE;
	77	goto failed;
	78	}
	79	buffer += prefix_size;
	80	}
	81	err = squashfs_read_metadata(sb, buffer, &start,
	82	&offset, name_size);
	83	if (err < 0)
	84	goto failed;
	85	if (buffer) {
	86	buffer[name_size] = '\0';
	87	buffer += name_size + 1;
	88	}
	89	rest -= prefix_size + name_size + 1;
	90	} else {
	91	/* no handler or insuffficient privileges, so skip */
	92	err = squashfs_read_metadata(sb, NULL, &start,
	93	&offset, name_size);
	94	if (err < 0)
	95	goto failed;
	96	}
	97
	98
	99	/* skip remaining xattr entry */
	100	err = squashfs_read_metadata(sb, &val, &start, &offset,
	101	sizeof(val));
	102	if (err < 0)
	103	goto failed;
	104
	105	err = squashfs_read_metadata(sb, NULL, &start, &offset,
	106	le32_to_cpu(val.vsize));
	107	if (err < 0)
	108	goto failed;
	109	}
	110	err = buffer_size - rest;
	111
	112	failed:
	113	return err;
	114	}
	115
	116
	117	static int squashfs_xattr_get(struct inode *inode, int name_index,
	118	const char name, void buffer, size_t buffer_size)
	119	{
	120	struct super_block *sb = inode->i_sb;
	121	struct squashfs_sb_info *msblk = sb->s_fs_info;
	122	u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
	123	+ msblk->xattr_table;
	124	int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
	125	int count = squashfs_i(inode)->xattr_count;
	126	int name_len = strlen(name);
	127	int err, vsize;
	128	char *target = kmalloc(name_len, GFP_KERNEL);
	129
	130	if (target == NULL)
	131	return -ENOMEM;
	132
	133	/* loop reading each xattr name */
	134	for (; count; count--) {
	135	struct squashfs_xattr_entry entry;
	136	struct squashfs_xattr_val val;
137	int type, prefix, name_size;
138
139	err = squashfs_read_metadata(sb, &entry, &start, &offset,
140	sizeof(entry));
141	if (err < 0)
142	goto failed;
143
144	name_size = le16_to_cpu(entry.size);
145	type = le16_to_cpu(entry.type);
146	prefix = type & SQUASHFS_XATTR_PREFIX_MASK;
147
5c80f5aa PL	148	if (prefix == name_index && name_size == name_len)
	149	err = squashfs_read_metadata(sb, target, &start,
	150	&offset, name_size);
	151	else
	152	err = squashfs_read_metadata(sb, NULL, &start,
	153	&offset, name_size);
f41d207c PL	154	if (err < 0)
	155	goto failed;
	156
	157	if (prefix == name_index && name_size == name_len &&
	158	strncmp(target, name, name_size) == 0) {
	159	/* found xattr */
	160	if (type & SQUASHFS_XATTR_VALUE_OOL) {
07724586 PL	161	__le64 xattr_val;
07724586 PL	162	u64 xattr;
f41d207c PL	163	/* val is a reference to the real location */
	164	err = squashfs_read_metadata(sb, &val, &start,
	165	&offset, sizeof(val));
	166	if (err < 0)
	167	goto failed;
07724586 PL	168	err = squashfs_read_metadata(sb, &xattr_val,
07724586 PL	169	&start, &offset, sizeof(xattr_val));
f41d207c PL	170	if (err < 0)
f41d207c PL	171	goto failed;
07724586	172	xattr = le64_to_cpu(xattr_val);
f41d207c PL	173	start = SQUASHFS_XATTR_BLK(xattr) +
	174	msblk->xattr_table;
	175	offset = SQUASHFS_XATTR_OFFSET(xattr);
	176	}
	177	/* read xattr value */
	178	err = squashfs_read_metadata(sb, &val, &start, &offset,
	179	sizeof(val));
	180	if (err < 0)
	181	goto failed;
	182
	183	vsize = le32_to_cpu(val.vsize);
	184	if (buffer) {
	185	if (vsize > buffer_size) {
	186	err = -ERANGE;
	187	goto failed;
	188	}
	189	err = squashfs_read_metadata(sb, buffer, &start,
	190	&offset, vsize);
	191	if (err < 0)
	192	goto failed;
	193	}
	194	break;
	195	}
	196
	197	/* no match, skip remaining xattr entry */
	198	err = squashfs_read_metadata(sb, &val, &start, &offset,
	199	sizeof(val));
	200	if (err < 0)
	201	goto failed;
	202	err = squashfs_read_metadata(sb, NULL, &start, &offset,
	203	le32_to_cpu(val.vsize));
	204	if (err < 0)
	205	goto failed;
	206	}
	207	err = count ? vsize : -ENODATA;
	208
	209	failed:
	210	kfree(target);
	211	return err;
	212	}
	213
	214
0ddaf72c AG	215	static size_t squashfs_xattr_handler_list(const struct xattr_handler *handler,
	216	struct dentry d, char list,
	217	size_t list_size, const char *name,
	218	size_t name_len)
f41d207c	219	{
0ddaf72c AG	220	int len = strlen(handler->prefix);
	221
	222	if (list && len <= list_size)
	223	memcpy(list, handler->prefix, len);
	224	return len;
f41d207c PL	225	}
f41d207c PL	226
0ddaf72c AG	227	static int squashfs_xattr_handler_get(const struct xattr_handler *handler,
	228	struct dentry d, const char name,
	229	void *buffer, size_t size)
f41d207c	230	{
0ddaf72c	231	return squashfs_xattr_get(d_inode(d), handler->flags, name,
f41d207c PL	232	buffer, size);
	233	}
	234
0ddaf72c AG	235	/*
	236	* User namespace support
	237	*/
f6db25a8	238	static const struct xattr_handler squashfs_xattr_user_handler = {
f41d207c	239	.prefix = XATTR_USER_PREFIX,
0ddaf72c AG	240	.flags = SQUASHFS_XATTR_USER,
	241	.list = squashfs_xattr_handler_list,
	242	.get = squashfs_xattr_handler_get
f41d207c PL	243	};
	244
	245	/*
	246	* Trusted namespace support
	247	*/
0ddaf72c AG	248	static size_t squashfs_trusted_xattr_handler_list(const struct xattr_handler *handler,
	249	struct dentry d, char list,
	250	size_t list_size, const char *name,
	251	size_t name_len)
f41d207c PL	252	{
	253	if (!capable(CAP_SYS_ADMIN))
	254	return 0;
0ddaf72c AG	255	return squashfs_xattr_handler_list(handler, d, list, list_size, name,
0ddaf72c AG	256	name_len);
f41d207c PL	257	}
f41d207c PL	258
f6db25a8	259	static const struct xattr_handler squashfs_xattr_trusted_handler = {
f41d207c	260	.prefix = XATTR_TRUSTED_PREFIX,
0ddaf72c AG	261	.flags = SQUASHFS_XATTR_TRUSTED,
	262	.list = squashfs_trusted_xattr_handler_list,
	263	.get = squashfs_xattr_handler_get
f41d207c PL	264	};
	265
	266	/*
	267	* Security namespace support
	268	*/
f6db25a8	269	static const struct xattr_handler squashfs_xattr_security_handler = {
f41d207c	270	.prefix = XATTR_SECURITY_PREFIX,
0ddaf72c AG	271	.flags = SQUASHFS_XATTR_SECURITY,
	272	.list = squashfs_xattr_handler_list,
	273	.get = squashfs_xattr_handler_get
f41d207c PL	274	};
f41d207c PL	275
a02956e4	276	static const struct xattr_handler *squashfs_xattr_handler(int type)
f41d207c PL	277	{
	278	if (type & ~(SQUASHFS_XATTR_PREFIX_MASK \| SQUASHFS_XATTR_VALUE_OOL))
	279	/* ignore unrecognised type */
	280	return NULL;
	281
	282	switch (type & SQUASHFS_XATTR_PREFIX_MASK) {
	283	case SQUASHFS_XATTR_USER:
	284	return &squashfs_xattr_user_handler;
	285	case SQUASHFS_XATTR_TRUSTED:
	286	return &squashfs_xattr_trusted_handler;
	287	case SQUASHFS_XATTR_SECURITY:
	288	return &squashfs_xattr_security_handler;
	289	default:
	290	/* ignore unrecognised type */
	291	return NULL;
	292	}
	293	}
	294
f6db25a8	295	const struct xattr_handler *squashfs_xattr_handlers[] = {
f41d207c PL	296	&squashfs_xattr_user_handler,
	297	&squashfs_xattr_trusted_handler,
	298	&squashfs_xattr_security_handler,
	299	NULL
	300	};
	301