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)  * export.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 make Squashfs filesystems exportable (NFS etc.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  * The export code uses an inode lookup table to map inode numbers passed in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  * filehandles to an inode location on disk.  This table is stored compressed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  * into metadata blocks.  A second index table is used to locate these.  This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  * second index table for speed of access (and because it is small) is read at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  * mount time and cached in memory.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  * The inode lookup table is used only by the export code, inode disk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * locations are directly encoded in directories, enabling direct access
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  * without an intermediate lookup for all operations except the export ops.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #include <linux/vfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include <linux/dcache.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) #include <linux/exportfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #include "squashfs_fs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) #include "squashfs_fs_sb.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) #include "squashfs_fs_i.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) #include "squashfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  * Look-up inode number (ino) in table, returning the inode location.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) static long long squashfs_inode_lookup(struct super_block *sb, int ino_num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	struct squashfs_sb_info *msblk = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	int blk = SQUASHFS_LOOKUP_BLOCK(ino_num - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	int offset = SQUASHFS_LOOKUP_BLOCK_OFFSET(ino_num - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	u64 start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	__le64 ino;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	TRACE("Entered squashfs_inode_lookup, inode_number = %d\n", ino_num);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	if (ino_num == 0 || (ino_num - 1) >= msblk->inodes)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	start = le64_to_cpu(msblk->inode_lookup_table[blk]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	err = squashfs_read_metadata(sb, &ino, &start, &offset, sizeof(ino));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	if (err < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 		return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	TRACE("squashfs_inode_lookup, inode = 0x%llx\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		(u64) le64_to_cpu(ino));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	return le64_to_cpu(ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) static struct dentry *squashfs_export_iget(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	unsigned int ino_num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 	long long ino;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	struct dentry *dentry = ERR_PTR(-ENOENT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	TRACE("Entered squashfs_export_iget\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	ino = squashfs_inode_lookup(sb, ino_num);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	if (ino >= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		dentry = d_obtain_alias(squashfs_iget(sb, ino, ino_num));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) static struct dentry *squashfs_fh_to_dentry(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 		struct fid *fid, int fh_len, int fh_type)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	if ((fh_type != FILEID_INO32_GEN && fh_type != FILEID_INO32_GEN_PARENT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 			|| fh_len < 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	return squashfs_export_iget(sb, fid->i32.ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) static struct dentry *squashfs_fh_to_parent(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 		struct fid *fid, int fh_len, int fh_type)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	if (fh_type != FILEID_INO32_GEN_PARENT || fh_len < 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	return squashfs_export_iget(sb, fid->i32.parent_ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) static struct dentry *squashfs_get_parent(struct dentry *child)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	struct inode *inode = d_inode(child);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	unsigned int parent_ino = squashfs_i(inode)->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	return squashfs_export_iget(inode->i_sb, parent_ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)  * Read uncompressed inode lookup table indexes off disk into memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) __le64 *squashfs_read_inode_lookup_table(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 		u64 lookup_table_start, u64 next_table, unsigned int inodes)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	unsigned int length = SQUASHFS_LOOKUP_BLOCK_BYTES(inodes);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	unsigned int indexes = SQUASHFS_LOOKUP_BLOCKS(inodes);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	int n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	__le64 *table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	u64 start, end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	TRACE("In read_inode_lookup_table, length %d\n", length);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	/* Sanity check values */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	/* there should always be at least one inode */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	if (inodes == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 		return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	 * The computed size of the lookup table (length bytes) should exactly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	 * match the table start and end points
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	if (length != (next_table - lookup_table_start))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	table = squashfs_read_table(sb, lookup_table_start, length);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	if (IS_ERR(table))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		return table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	 * table0], table[1], ... table[indexes - 1] store the locations
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 	 * of the compressed inode lookup blocks.  Each entry should be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	 * less than the next (i.e. table[0] < table[1]), and the difference
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	 * between them should be SQUASHFS_METADATA_SIZE or less.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	 * table[indexes - 1] should  be less than lookup_table_start, and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	 * again the difference should be SQUASHFS_METADATA_SIZE or less
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	for (n = 0; n < (indexes - 1); n++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		start = le64_to_cpu(table[n]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		end = le64_to_cpu(table[n + 1]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		if (start >= end
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		    || (end - start) >
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 		    (SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 			kfree(table);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 			return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	start = le64_to_cpu(table[indexes - 1]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	if (start >= lookup_table_start ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	    (lookup_table_start - start) >
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	    (SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 		kfree(table);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 		return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	return table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) const struct export_operations squashfs_export_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	.fh_to_dentry = squashfs_fh_to_dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	.fh_to_parent = squashfs_fh_to_parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	.get_parent = squashfs_get_parent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) };