[mirror_ubuntu-jammy-kernel.git] / fs / squashfs / xattr_id.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2010
 * Phillip Lougher <phillip@squashfs.org.uk>
 *
 * xattr_id.c
 */

/*
 * This file implements code to map the 32-bit xattr id stored in the inode
 * into the on disk location of the xattr data.
 */

#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/slab.h>

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

/*
 * Map xattr id using the xattr id look up table
 */
int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
		int *count, unsigned int *size, unsigned long long *xattr)
{
	struct squashfs_sb_info *msblk = sb->s_fs_info;
	int block = SQUASHFS_XATTR_BLOCK(index);
	int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
	u64 start_block;
	struct squashfs_xattr_id id;
	int err;

	if (index >= msblk->xattr_ids)
		return -EINVAL;

	start_block = le64_to_cpu(msblk->xattr_id_table[block]);

	err = squashfs_read_metadata(sb, &id, &start_block, &offset,
							sizeof(id));
	if (err < 0)
		return err;

	*xattr = le64_to_cpu(id.xattr);
	*size = le32_to_cpu(id.size);
	*count = le32_to_cpu(id.count);
	return 0;
}


/*
 * Read uncompressed xattr id lookup table indexes from disk into memory
 */
__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 table_start,
		u64 *xattr_table_start, int *xattr_ids)
{
	struct squashfs_sb_info *msblk = sb->s_fs_info;
	unsigned int len, indexes;
	struct squashfs_xattr_id_table *id_table;
	__le64 *table;
	u64 start, end;
	int n;

	id_table = squashfs_read_table(sb, table_start, sizeof(*id_table));
	if (IS_ERR(id_table))
		return (__le64 *) id_table;

	*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
	*xattr_ids = le32_to_cpu(id_table->xattr_ids);
	kfree(id_table);

	/* Sanity check values */

	/* there is always at least one xattr id */
	if (*xattr_ids == 0)
		return ERR_PTR(-EINVAL);

	len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
	indexes = SQUASHFS_XATTR_BLOCKS(*xattr_ids);

	/*
	 * The computed size of the index table (len bytes) should exactly
	 * match the table start and end points
	 */
	start = table_start + sizeof(*id_table);
	end = msblk->bytes_used;

	if (len != (end - start))
		return ERR_PTR(-EINVAL);

	table = squashfs_read_table(sb, start, len);
	if (IS_ERR(table))
		return table;

	/* table[0], table[1], ... table[indexes - 1] store the locations
	 * of the compressed xattr id blocks.  Each entry should be less than
	 * the next (i.e. table[0] < table[1]), and the difference between them
	 * should be SQUASHFS_METADATA_SIZE or less.  table[indexes - 1]
	 * should be less than table_start, and again the difference
	 * shouls be SQUASHFS_METADATA_SIZE or less.
	 *
	 * Finally xattr_table_start should be less than table[0].
	 */
	for (n = 0; n < (indexes - 1); n++) {
		start = le64_to_cpu(table[n]);
		end = le64_to_cpu(table[n + 1]);

		if (start >= end || (end - start) > SQUASHFS_METADATA_SIZE) {
			kfree(table);
			return ERR_PTR(-EINVAL);
		}
	}

	start = le64_to_cpu(table[indexes - 1]);
	if (start >= table_start || (table_start - start) > SQUASHFS_METADATA_SIZE) {
		kfree(table);
		return ERR_PTR(-EINVAL);
	}

	if (*xattr_table_start >= le64_to_cpu(table[0])) {
		kfree(table);
		return ERR_PTR(-EINVAL);
	}

	return table;
}
Commit	Line	Data
68252eb5	1	// SPDX-License-Identifier: GPL-2.0-or-later
4b5397dc PL	2	/*
	3	* Squashfs - a compressed read only filesystem for Linux
	4	*
	5	* Copyright (c) 2010
d7f2ff67	6	* Phillip Lougher <phillip@squashfs.org.uk>
4b5397dc	7	*
4b5397dc PL	8	* xattr_id.c
	9	*/
	10
	11	/*
	12	* This file implements code to map the 32-bit xattr id stored in the inode
	13	* into the on disk location of the xattr data.
	14	*/
	15
	16	#include <linux/fs.h>
	17	#include <linux/vfs.h>
	18	#include <linux/slab.h>
	19
	20	#include "squashfs_fs.h"
	21	#include "squashfs_fs_sb.h"
4b5397dc	22	#include "squashfs.h"
5f3b321d	23	#include "xattr.h"
4b5397dc PL	24
	25	/*
	26	* Map xattr id using the xattr id look up table
	27	*/
	28	int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
aa5b1894	29	int count, unsigned int size, unsigned long long *xattr)
4b5397dc PL	30	{
	31	struct squashfs_sb_info *msblk = sb->s_fs_info;
	32	int block = SQUASHFS_XATTR_BLOCK(index);
	33	int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
506220d2	34	u64 start_block;
4b5397dc PL	35	struct squashfs_xattr_id id;
	36	int err;
	37
506220d2 PL	38	if (index >= msblk->xattr_ids)
	39	return -EINVAL;
	40
	41	start_block = le64_to_cpu(msblk->xattr_id_table[block]);
	42
4b5397dc PL	43	err = squashfs_read_metadata(sb, &id, &start_block, &offset,
	44	sizeof(id));
	45	if (err < 0)
	46	return err;
	47
	48	*xattr = le64_to_cpu(id.xattr);
	49	*size = le32_to_cpu(id.size);
	50	*count = le32_to_cpu(id.count);
	51	return 0;
	52	}
	53
	54
	55	/*
	56	* Read uncompressed xattr id lookup table indexes from disk into memory
	57	*/
506220d2	58	__le64 squashfs_read_xattr_id_table(struct super_block sb, u64 table_start,
4b5397dc PL	59	u64 xattr_table_start, int xattr_ids)
4b5397dc PL	60	{
506220d2 PL	61	struct squashfs_sb_info *msblk = sb->s_fs_info;
506220d2 PL	62	unsigned int len, indexes;
82de647e	63	struct squashfs_xattr_id_table *id_table;
506220d2 PL	64	__le64 *table;
	65	u64 start, end;
	66	int n;
82de647e	67
506220d2	68	id_table = squashfs_read_table(sb, table_start, sizeof(*id_table));
82de647e PL	69	if (IS_ERR(id_table))
82de647e PL	70	return (__le64 *) id_table;
4b5397dc	71
82de647e PL	72	*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
	73	*xattr_ids = le32_to_cpu(id_table->xattr_ids);
	74	kfree(id_table);
6f048645 PL	75
	76	/* Sanity check values */
	77
	78	/* there is always at least one xattr id */
	79	if (*xattr_ids == 0)
	80	return ERR_PTR(-EINVAL);
	81
506220d2 PL	82	len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
	83	indexes = SQUASHFS_XATTR_BLOCKS(*xattr_ids);
	84
	85	/*
	86	* The computed size of the index table (len bytes) should exactly
	87	* match the table start and end points
	88	*/
	89	start = table_start + sizeof(*id_table);
	90	end = msblk->bytes_used;
	91
	92	if (len != (end - start))
6f048645 PL	93	return ERR_PTR(-EINVAL);
6f048645 PL	94
506220d2 PL	95	table = squashfs_read_table(sb, start, len);
	96	if (IS_ERR(table))
	97	return table;
	98
	99	/* table[0], table[1], ... table[indexes - 1] store the locations
	100	* of the compressed xattr id blocks. Each entry should be less than
	101	* the next (i.e. table[0] < table[1]), and the difference between them
	102	* should be SQUASHFS_METADATA_SIZE or less. table[indexes - 1]
	103	* should be less than table_start, and again the difference
	104	* shouls be SQUASHFS_METADATA_SIZE or less.
	105	*
	106	* Finally xattr_table_start should be less than table[0].
	107	*/
	108	for (n = 0; n < (indexes - 1); n++) {
	109	start = le64_to_cpu(table[n]);
	110	end = le64_to_cpu(table[n + 1]);
	111
	112	if (start >= end \|\| (end - start) > SQUASHFS_METADATA_SIZE) {
	113	kfree(table);
	114	return ERR_PTR(-EINVAL);
	115	}
	116	}
	117
	118	start = le64_to_cpu(table[indexes - 1]);
	119	if (start >= table_start \|\| (table_start - start) > SQUASHFS_METADATA_SIZE) {
	120	kfree(table);
	121	return ERR_PTR(-EINVAL);
	122	}
4b5397dc	123
506220d2 PL	124	if (*xattr_table_start >= le64_to_cpu(table[0])) {
	125	kfree(table);
	126	return ERR_PTR(-EINVAL);
	127	}
4b5397dc	128
506220d2	129	return table;
4b5397dc	130	}