68252eb5f8
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 23 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.458548087@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
90 lines
2.3 KiB
C
90 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
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* Phillip Lougher <phillip@squashfs.org.uk>
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*
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* id.c
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*/
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/*
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* This file implements code to handle uids and gids.
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*
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* For space efficiency regular files store uid and gid indexes, which are
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* converted to 32-bit uids/gids using an id look up table. This table is
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* stored compressed into metadata blocks. A second index table is used to
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* locate these. This second index table for speed of access (and because it
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* is small) is read at mount time and cached in memory.
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*/
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#include <linux/fs.h>
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#include <linux/vfs.h>
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#include <linux/slab.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "squashfs.h"
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/*
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* Map uid/gid index into real 32-bit uid/gid using the id look up table
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*/
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int squashfs_get_id(struct super_block *sb, unsigned int index,
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unsigned int *id)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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int block = SQUASHFS_ID_BLOCK(index);
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int offset = SQUASHFS_ID_BLOCK_OFFSET(index);
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u64 start_block = le64_to_cpu(msblk->id_table[block]);
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__le32 disk_id;
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int err;
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err = squashfs_read_metadata(sb, &disk_id, &start_block, &offset,
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sizeof(disk_id));
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if (err < 0)
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return err;
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*id = le32_to_cpu(disk_id);
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return 0;
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}
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/*
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* Read uncompressed id lookup table indexes from disk into memory
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*/
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__le64 *squashfs_read_id_index_table(struct super_block *sb,
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u64 id_table_start, u64 next_table, unsigned short no_ids)
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{
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unsigned int length = SQUASHFS_ID_BLOCK_BYTES(no_ids);
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__le64 *table;
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TRACE("In read_id_index_table, length %d\n", length);
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/* Sanity check values */
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/* there should always be at least one id */
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if (no_ids == 0)
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return ERR_PTR(-EINVAL);
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/*
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* length bytes should not extend into the next table - this check
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* also traps instances where id_table_start is incorrectly larger
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* than the next table start
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*/
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if (id_table_start + length > next_table)
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return ERR_PTR(-EINVAL);
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table = squashfs_read_table(sb, id_table_start, length);
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/*
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* table[0] points to the first id lookup table metadata block, this
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* should be less than id_table_start
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*/
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if (!IS_ERR(table) && le64_to_cpu(table[0]) >= id_table_start) {
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kfree(table);
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return ERR_PTR(-EINVAL);
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}
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return table;
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}
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