Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3)  * Squashfs - a compressed read only filesystem for Linux
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5)  * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)  * Phillip Lougher <phillip@squashfs.org.uk>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8)  * fragment.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)  * This file implements code to handle compressed fragments (tail-end packed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)  * datablocks).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)  * Regular files contain a fragment index which is mapped to a fragment
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)  * location on disk and compressed size using a fragment lookup table.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)  * Like everything in Squashfs this fragment lookup table is itself stored
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)  * compressed into metadata blocks.  A second index table is used to locate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)  * these.  This second index table for speed of access (and because it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)  * is small) is read at mount time and cached in memory.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) #include <linux/vfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #include "squashfs_fs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) #include "squashfs_fs_sb.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #include "squashfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)  * Look-up fragment using the fragment index table.  Return the on disk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)  * location of the fragment and its compressed size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) int squashfs_frag_lookup(struct super_block *sb, unsigned int fragment,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 				u64 *fragment_block)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 	struct squashfs_sb_info *msblk = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 	int block, offset, size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 	struct squashfs_fragment_entry fragment_entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 	u64 start_block;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 	if (fragment >= msblk->fragments)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 		return -EIO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 	block = SQUASHFS_FRAGMENT_INDEX(fragment);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 	offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 	start_block = le64_to_cpu(msblk->fragment_index[block]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 	size = squashfs_read_metadata(sb, &fragment_entry, &start_block,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 					&offset, sizeof(fragment_entry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 	if (size < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 		return size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 	*fragment_block = le64_to_cpu(fragment_entry.start_block);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 	return squashfs_block_size(fragment_entry.size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)  * Read the uncompressed fragment lookup table indexes off disk into memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) __le64 *squashfs_read_fragment_index_table(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) 	u64 fragment_table_start, u64 next_table, unsigned int fragments)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) 	unsigned int length = SQUASHFS_FRAGMENT_INDEX_BYTES(fragments);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) 	__le64 *table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) 	 * Sanity check, length bytes should not extend into the next table -
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) 	 * this check also traps instances where fragment_table_start is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) 	 * incorrectly larger than the next table start
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) 	if (fragment_table_start + length > next_table)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) 		return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) 	table = squashfs_read_table(sb, fragment_table_start, length);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) 	 * table[0] points to the first fragment table metadata block, this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) 	 * should be less than fragment_table_start
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) 	if (!IS_ERR(table) && le64_to_cpu(table[0]) >= fragment_table_start) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) 		kfree(table);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) 		return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) 	return table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) }