1 files changed, 587 insertions, 0 deletions

diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
new file mode 100644
index 000000000..32565dafa
--- /dev/null
+++ b/fs/squashfs/super.c
@@ -0,0 +1,587 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * super.c
+ */
+
+/*
+ * This file implements code to read the superblock, read and initialise
+ * in-memory structures at mount time, and all the VFS glue code to register
+ * the filesystem.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/blkdev.h>
+#include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/magic.h>
+#include <linux/xattr.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "decompressor.h"
+#include "xattr.h"
+
+static struct file_system_type squashfs_fs_type;
+static const struct super_operations squashfs_super_ops;
+
+enum Opt_errors {
+	Opt_errors_continue,
+	Opt_errors_panic,
+};
+
+enum squashfs_param {
+	Opt_errors,
+};
+
+struct squashfs_mount_opts {
+	enum Opt_errors errors;
+};
+
+static const struct constant_table squashfs_param_errors[] = {
+	{"continue",   Opt_errors_continue },
+	{"panic",      Opt_errors_panic },
+	{}
+};
+
+static const struct fs_parameter_spec squashfs_fs_parameters[] = {
+	fsparam_enum("errors", Opt_errors, squashfs_param_errors),
+	{}
+};
+
+static int squashfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct squashfs_mount_opts *opts = fc->fs_private;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, squashfs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_errors:
+		opts->errors = result.uint_32;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct squashfs_decompressor *supported_squashfs_filesystem(
+	struct fs_context *fc,
+	short major, short minor, short id)
+{
+	const struct squashfs_decompressor *decompressor;
+
+	if (major < SQUASHFS_MAJOR) {
+		errorf(fc, "Major/Minor mismatch, older Squashfs %d.%d "
+		       "filesystems are unsupported", major, minor);
+		return NULL;
+	} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
+		errorf(fc, "Major/Minor mismatch, trying to mount newer "
+		       "%d.%d filesystem", major, minor);
+		errorf(fc, "Please update your kernel");
+		return NULL;
+	}
+
+	decompressor = squashfs_lookup_decompressor(id);
+	if (!decompressor->supported) {
+		errorf(fc, "Filesystem uses \"%s\" compression. This is not supported",
+		       decompressor->name);
+		return NULL;
+	}
+
+	return decompressor;
+}
+
+
+static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct squashfs_mount_opts *opts = fc->fs_private;
+	struct squashfs_sb_info *msblk;
+	struct squashfs_super_block *sblk = NULL;
+	struct inode *root;
+	long long root_inode;
+	unsigned short flags;
+	unsigned int fragments;
+	u64 lookup_table_start, xattr_id_table_start, next_table;
+	int err;
+
+	TRACE("Entered squashfs_fill_superblock\n");
+
+	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
+	if (sb->s_fs_info == NULL) {
+		ERROR("Failed to allocate squashfs_sb_info\n");
+		return -ENOMEM;
+	}
+	msblk = sb->s_fs_info;
+
+	msblk->panic_on_errors = (opts->errors == Opt_errors_panic);
+
+	msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
+	msblk->devblksize_log2 = ffz(~msblk->devblksize);
+
+	mutex_init(&msblk->meta_index_mutex);
+
+	/*
+	 * msblk->bytes_used is checked in squashfs_read_table to ensure reads
+	 * are not beyond filesystem end.  But as we're using
+	 * squashfs_read_table here to read the superblock (including the value
+	 * of bytes_used) we need to set it to an initial sensible dummy value
+	 */
+	msblk->bytes_used = sizeof(*sblk);
+	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
+
+	if (IS_ERR(sblk)) {
+		errorf(fc, "unable to read squashfs_super_block");
+		err = PTR_ERR(sblk);
+		sblk = NULL;
+		goto failed_mount;
+	}
+
+	err = -EINVAL;
+
+	/* Check it is a SQUASHFS superblock */
+	sb->s_magic = le32_to_cpu(sblk->s_magic);
+	if (sb->s_magic != SQUASHFS_MAGIC) {
+		if (!(fc->sb_flags & SB_SILENT))
+			errorf(fc, "Can't find a SQUASHFS superblock on %pg",
+			       sb->s_bdev);
+		goto failed_mount;
+	}
+
+	/* Check the MAJOR & MINOR versions and lookup compression type */
+	msblk->decompressor = supported_squashfs_filesystem(
+			fc,
+			le16_to_cpu(sblk->s_major),
+			le16_to_cpu(sblk->s_minor),
+			le16_to_cpu(sblk->compression));
+	if (msblk->decompressor == NULL)
+		goto failed_mount;
+
+	/* Check the filesystem does not extend beyond the end of the
+	   block device */
+	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
+	if (msblk->bytes_used < 0 ||
+	    msblk->bytes_used > bdev_nr_bytes(sb->s_bdev))
+		goto failed_mount;
+
+	/* Check block size for sanity */
+	msblk->block_size = le32_to_cpu(sblk->block_size);
+	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
+		goto insanity;
+
+	/*
+	 * Check the system page size is not larger than the filesystem
+	 * block size (by default 128K).  This is currently not supported.
+	 */
+	if (PAGE_SIZE > msblk->block_size) {
+		errorf(fc, "Page size > filesystem block size (%d).  This is "
+		       "currently not supported!", msblk->block_size);
+		goto failed_mount;
+	}
+
+	/* Check block log for sanity */
+	msblk->block_log = le16_to_cpu(sblk->block_log);
+	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
+		goto failed_mount;
+
+	/* Check that block_size and block_log match */
+	if (msblk->block_size != (1 << msblk->block_log))
+		goto insanity;
+
+	/* Check the root inode for sanity */
+	root_inode = le64_to_cpu(sblk->root_inode);
+	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
+		goto insanity;
+
+	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
+	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
+	msblk->inodes = le32_to_cpu(sblk->inodes);
+	msblk->fragments = le32_to_cpu(sblk->fragments);
+	msblk->ids = le16_to_cpu(sblk->no_ids);
+	flags = le16_to_cpu(sblk->flags);
+
+	TRACE("Found valid superblock on %pg\n", sb->s_bdev);
+	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
+				? "un" : "");
+	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
+				? "un" : "");
+	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
+	TRACE("Block size %d\n", msblk->block_size);
+	TRACE("Number of inodes %d\n", msblk->inodes);
+	TRACE("Number of fragments %d\n", msblk->fragments);
+	TRACE("Number of ids %d\n", msblk->ids);
+	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
+	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
+	TRACE("sblk->fragment_table_start %llx\n",
+		(u64) le64_to_cpu(sblk->fragment_table_start));
+	TRACE("sblk->id_table_start %llx\n",
+		(u64) le64_to_cpu(sblk->id_table_start));
+
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_time_min = 0;
+	sb->s_time_max = U32_MAX;
+	sb->s_flags |= SB_RDONLY;
+	sb->s_op = &squashfs_super_ops;
+
+	err = -ENOMEM;
+
+	msblk->block_cache = squashfs_cache_init("metadata",
+			SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
+	if (msblk->block_cache == NULL)
+		goto failed_mount;
+
+	/* Allocate read_page block */
+	msblk->read_page = squashfs_cache_init("data",
+		squashfs_max_decompressors(), msblk->block_size);
+	if (msblk->read_page == NULL) {
+		errorf(fc, "Failed to allocate read_page block");
+		goto failed_mount;
+	}
+
+	msblk->stream = squashfs_decompressor_setup(sb, flags);
+	if (IS_ERR(msblk->stream)) {
+		err = PTR_ERR(msblk->stream);
+		msblk->stream = NULL;
+		goto insanity;
+	}
+
+	/* Handle xattrs */
+	sb->s_xattr = squashfs_xattr_handlers;
+	xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
+	if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
+		next_table = msblk->bytes_used;
+		goto allocate_id_index_table;
+	}
+
+	/* Allocate and read xattr id lookup table */
+	msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
+		xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
+	if (IS_ERR(msblk->xattr_id_table)) {
+		errorf(fc, "unable to read xattr id index table");
+		err = PTR_ERR(msblk->xattr_id_table);
+		msblk->xattr_id_table = NULL;
+		if (err != -ENOTSUPP)
+			goto failed_mount;
+	}
+	next_table = msblk->xattr_table;
+
+allocate_id_index_table:
+	/* Allocate and read id index table */
+	msblk->id_table = squashfs_read_id_index_table(sb,
+		le64_to_cpu(sblk->id_table_start), next_table, msblk->ids);
+	if (IS_ERR(msblk->id_table)) {
+		errorf(fc, "unable to read id index table");
+		err = PTR_ERR(msblk->id_table);
+		msblk->id_table = NULL;
+		goto failed_mount;
+	}
+	next_table = le64_to_cpu(msblk->id_table[0]);
+
+	/* Handle inode lookup table */
+	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
+	if (lookup_table_start == SQUASHFS_INVALID_BLK)
+		goto handle_fragments;
+
+	/* Allocate and read inode lookup table */
+	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
+		lookup_table_start, next_table, msblk->inodes);
+	if (IS_ERR(msblk->inode_lookup_table)) {
+		errorf(fc, "unable to read inode lookup table");
+		err = PTR_ERR(msblk->inode_lookup_table);
+		msblk->inode_lookup_table = NULL;
+		goto failed_mount;
+	}
+	next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
+
+	sb->s_export_op = &squashfs_export_ops;
+
+handle_fragments:
+	fragments = msblk->fragments;
+	if (fragments == 0)
+		goto check_directory_table;
+
+	msblk->fragment_cache = squashfs_cache_init("fragment",
+		SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
+	if (msblk->fragment_cache == NULL) {
+		err = -ENOMEM;
+		goto failed_mount;
+	}
+
+	/* Allocate and read fragment index table */
+	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
+		le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
+	if (IS_ERR(msblk->fragment_index)) {
+		errorf(fc, "unable to read fragment index table");
+		err = PTR_ERR(msblk->fragment_index);
+		msblk->fragment_index = NULL;
+		goto failed_mount;
+	}
+	next_table = le64_to_cpu(msblk->fragment_index[0]);
+
+check_directory_table:
+	/* Sanity check directory_table */
+	if (msblk->directory_table > next_table) {
+		err = -EINVAL;
+		goto insanity;
+	}
+
+	/* Sanity check inode_table */
+	if (msblk->inode_table >= msblk->directory_table) {
+		err = -EINVAL;
+		goto insanity;
+	}
+
+	/* allocate root */
+	root = new_inode(sb);
+	if (!root) {
+		err = -ENOMEM;
+		goto failed_mount;
+	}
+
+	err = squashfs_read_inode(root, root_inode);
+	if (err) {
+		make_bad_inode(root);
+		iput(root);
+		goto failed_mount;
+	}
+	insert_inode_hash(root);
+
+	sb->s_root = d_make_root(root);
+	if (sb->s_root == NULL) {
+		ERROR("Root inode create failed\n");
+		err = -ENOMEM;
+		goto failed_mount;
+	}
+
+	TRACE("Leaving squashfs_fill_super\n");
+	kfree(sblk);
+	return 0;
+
+insanity:
+	errorf(fc, "squashfs image failed sanity check");
+failed_mount:
+	squashfs_cache_delete(msblk->block_cache);
+	squashfs_cache_delete(msblk->fragment_cache);
+	squashfs_cache_delete(msblk->read_page);
+	squashfs_decompressor_destroy(msblk);
+	kfree(msblk->inode_lookup_table);
+	kfree(msblk->fragment_index);
+	kfree(msblk->id_table);
+	kfree(msblk->xattr_id_table);
+	kfree(sb->s_fs_info);
+	sb->s_fs_info = NULL;
+	kfree(sblk);
+	return err;
+}
+
+static int squashfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, squashfs_fill_super);
+}
+
+static int squashfs_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	struct squashfs_mount_opts *opts = fc->fs_private;
+
+	sync_filesystem(fc->root->d_sb);
+	fc->sb_flags |= SB_RDONLY;
+
+	msblk->panic_on_errors = (opts->errors == Opt_errors_panic);
+
+	return 0;
+}
+
+static void squashfs_free_fs_context(struct fs_context *fc)
+{
+	kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations squashfs_context_ops = {
+	.get_tree	= squashfs_get_tree,
+	.free		= squashfs_free_fs_context,
+	.parse_param	= squashfs_parse_param,
+	.reconfigure	= squashfs_reconfigure,
+};
+
+static int squashfs_show_options(struct seq_file *s, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+
+	if (msblk->panic_on_errors)
+		seq_puts(s, ",errors=panic");
+	else
+		seq_puts(s, ",errors=continue");
+
+	return 0;
+}
+
+static int squashfs_init_fs_context(struct fs_context *fc)
+{
+	struct squashfs_mount_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return -ENOMEM;
+
+	fc->fs_private = opts;
+	fc->ops = &squashfs_context_ops;
+	return 0;
+}
+
+static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
+	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
+
+	TRACE("Entered squashfs_statfs\n");
+
+	buf->f_type = SQUASHFS_MAGIC;
+	buf->f_bsize = msblk->block_size;
+	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
+	buf->f_bfree = buf->f_bavail = 0;
+	buf->f_files = msblk->inodes;
+	buf->f_ffree = 0;
+	buf->f_namelen = SQUASHFS_NAME_LEN;
+	buf->f_fsid = u64_to_fsid(id);
+
+	return 0;
+}
+
+
+static void squashfs_put_super(struct super_block *sb)
+{
+	if (sb->s_fs_info) {
+		struct squashfs_sb_info *sbi = sb->s_fs_info;
+		squashfs_cache_delete(sbi->block_cache);
+		squashfs_cache_delete(sbi->fragment_cache);
+		squashfs_cache_delete(sbi->read_page);
+		squashfs_decompressor_destroy(sbi);
+		kfree(sbi->id_table);
+		kfree(sbi->fragment_index);
+		kfree(sbi->meta_index);
+		kfree(sbi->inode_lookup_table);
+		kfree(sbi->xattr_id_table);
+		kfree(sb->s_fs_info);
+		sb->s_fs_info = NULL;
+	}
+}
+
+static struct kmem_cache *squashfs_inode_cachep;
+
+
+static void init_once(void *foo)
+{
+	struct squashfs_inode_info *ei = foo;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+
+static int __init init_inodecache(void)
+{
+	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
+		sizeof(struct squashfs_inode_info), 0,
+		SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
+		init_once);
+
+	return squashfs_inode_cachep ? 0 : -ENOMEM;
+}
+
+
+static void destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(squashfs_inode_cachep);
+}
+
+
+static int __init init_squashfs_fs(void)
+{
+	int err = init_inodecache();
+
+	if (err)
+		return err;
+
+	err = register_filesystem(&squashfs_fs_type);
+	if (err) {
+		destroy_inodecache();
+		return err;
+	}
+
+	pr_info("version 4.0 (2009/01/31) Phillip Lougher\n");
+
+	return 0;
+}
+
+
+static void __exit exit_squashfs_fs(void)
+{
+	unregister_filesystem(&squashfs_fs_type);
+	destroy_inodecache();
+}
+
+
+static struct inode *squashfs_alloc_inode(struct super_block *sb)
+{
+	struct squashfs_inode_info *ei =
+		alloc_inode_sb(sb, squashfs_inode_cachep, GFP_KERNEL);
+
+	return ei ? &ei->vfs_inode : NULL;
+}
+
+
+static void squashfs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
+}
+
+static struct file_system_type squashfs_fs_type = {
+	.owner = THIS_MODULE,
+	.name = "squashfs",
+	.init_fs_context = squashfs_init_fs_context,
+	.parameters = squashfs_fs_parameters,
+	.kill_sb = kill_block_super,
+	.fs_flags = FS_REQUIRES_DEV
+};
+MODULE_ALIAS_FS("squashfs");
+
+static const struct super_operations squashfs_super_ops = {
+	.alloc_inode = squashfs_alloc_inode,
+	.free_inode = squashfs_free_inode,
+	.statfs = squashfs_statfs,
+	.put_super = squashfs_put_super,
+	.show_options = squashfs_show_options,
+};
+
+module_init(init_squashfs_fs);
+module_exit(exit_squashfs_fs);
+MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
+MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
+MODULE_LICENSE("GPL");