fs/squashfs/xattr.c - linux - Git at Google

 /*
  * Squashfs - a compressed read only filesystem for Linux
  *
  * Copyright (c) 2010
  * Phillip Lougher <phillip@lougher.demon.co.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_id.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->d_inode;
 	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(d, buffer, rest, NULL,
 				name_size, handler->flags);
 		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;

 		err = squashfs_read_metadata(sb, target, &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 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, &start,
 					 &offset, sizeof(xattr));
 				if (err < 0)
 					goto failed;
 				xattr = le64_to_cpu(xattr);
 				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;
 }


 /*
  * User namespace support
  */
 static size_t squashfs_user_list(struct dentry *d, char *list, size_t list_size,
 	const char *name, size_t name_len, int type)
 {
 	if (list && XATTR_USER_PREFIX_LEN <= list_size)
 		memcpy(list, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
 	return XATTR_USER_PREFIX_LEN;
 }

 static int squashfs_user_get(struct dentry *d, const char *name, void *buffer,
 	size_t size, int type)
 {
 	if (name[0] == '\0')
 		return  -EINVAL;

 	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_USER, name,
 		buffer, size);
 }

 static const struct xattr_handler squashfs_xattr_user_handler = {
 	.prefix	= XATTR_USER_PREFIX,
 	.list	= squashfs_user_list,
 	.get	= squashfs_user_get
 };

 /*
  * Trusted namespace support
  */
 static size_t squashfs_trusted_list(struct dentry *d, char *list,
 	size_t list_size, const char *name, size_t name_len, int type)
 {
 	if (!capable(CAP_SYS_ADMIN))
 		return 0;

 	if (list && XATTR_TRUSTED_PREFIX_LEN <= list_size)
 		memcpy(list, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
 	return XATTR_TRUSTED_PREFIX_LEN;
 }

 static int squashfs_trusted_get(struct dentry *d, const char *name,
 	void *buffer, size_t size, int type)
 {
 	if (name[0] == '\0')
 		return  -EINVAL;

 	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_TRUSTED, name,
 		buffer, size);
 }

 static const struct xattr_handler squashfs_xattr_trusted_handler = {
 	.prefix	= XATTR_TRUSTED_PREFIX,
 	.list	= squashfs_trusted_list,
 	.get	= squashfs_trusted_get
 };

 /*
  * Security namespace support
  */
 static size_t squashfs_security_list(struct dentry *d, char *list,
 	size_t list_size, const char *name, size_t name_len, int type)
 {
 	if (list && XATTR_SECURITY_PREFIX_LEN <= list_size)
 		memcpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
 	return XATTR_SECURITY_PREFIX_LEN;
 }

 static int squashfs_security_get(struct dentry *d, const char *name,
 	void *buffer, size_t size, int type)
 {
 	if (name[0] == '\0')
 		return  -EINVAL;

 	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_SECURITY, name,
 		buffer, size);
 }

 static const struct xattr_handler squashfs_xattr_security_handler = {
 	.prefix	= XATTR_SECURITY_PREFIX,
 	.list	= squashfs_security_list,
 	.get	= squashfs_security_get
 };

 static inline 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
 };
	/*
	* Squashfs - a compressed read only filesystem for Linux
	*
	* Copyright (c) 2010
	* Phillip Lougher <phillip@lougher.demon.co.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_id.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->d_inode;
	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(d, buffer, rest, NULL,
	name_size, handler->flags);
	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;

	err = squashfs_read_metadata(sb, target, &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 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, &start,
	&offset, sizeof(xattr));
	if (err < 0)
	goto failed;
	xattr = le64_to_cpu(xattr);
	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;
	}


	/*
	* User namespace support
	*/
	static size_t squashfs_user_list(struct dentry d, char list, size_t list_size,
	const char *name, size_t name_len, int type)
	{
	if (list && XATTR_USER_PREFIX_LEN <= list_size)
	memcpy(list, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
	return XATTR_USER_PREFIX_LEN;
	}

	static int squashfs_user_get(struct dentry d, const char name, void *buffer,
	size_t size, int type)
	{
	if (name[0] == '\0')
	return -EINVAL;

	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_USER, name,
	buffer, size);
	}

	static const struct xattr_handler squashfs_xattr_user_handler = {
	.prefix = XATTR_USER_PREFIX,
	.list = squashfs_user_list,
	.get = squashfs_user_get
	};

	/*
	* Trusted namespace support
	*/
	static size_t squashfs_trusted_list(struct dentry d, char list,
	size_t list_size, const char *name, size_t name_len, int type)
	{
	if (!capable(CAP_SYS_ADMIN))
	return 0;

	if (list && XATTR_TRUSTED_PREFIX_LEN <= list_size)
	memcpy(list, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
	return XATTR_TRUSTED_PREFIX_LEN;
	}

	static int squashfs_trusted_get(struct dentry d, const char name,
	void *buffer, size_t size, int type)
	{
	if (name[0] == '\0')
	return -EINVAL;

	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_TRUSTED, name,
	buffer, size);
	}

	static const struct xattr_handler squashfs_xattr_trusted_handler = {
	.prefix = XATTR_TRUSTED_PREFIX,
	.list = squashfs_trusted_list,
	.get = squashfs_trusted_get
	};

	/*
	* Security namespace support
	*/
	static size_t squashfs_security_list(struct dentry d, char list,
	size_t list_size, const char *name, size_t name_len, int type)
	{
	if (list && XATTR_SECURITY_PREFIX_LEN <= list_size)
	memcpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
	return XATTR_SECURITY_PREFIX_LEN;
	}

	static int squashfs_security_get(struct dentry d, const char name,
	void *buffer, size_t size, int type)
	{
	if (name[0] == '\0')
	return -EINVAL;

	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_SECURITY, name,
	buffer, size);
	}

	static const struct xattr_handler squashfs_xattr_security_handler = {
	.prefix = XATTR_SECURITY_PREFIX,
	.list = squashfs_security_list,
	.get = squashfs_security_get
	};

	static inline 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
	};