1 files changed, 485 insertions, 0 deletions
diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
new file mode 100644
index 000000000..c578e772c
--- /dev/null
+++ b/fs/vboxsf/super.c
@@ -0,0 +1,485 @@
+// SPDX-License-Identifier: MIT
+/*
+ * VirtualBox Guest Shared Folders support: Virtual File System.
+ *
+ * Module initialization/finalization
+ * File system registration/deregistration
+ * Superblock reading
+ * Few utility functions
+ *
+ * Copyright (C) 2006-2018 Oracle Corporation
+ */
+
+#include <linux/idr.h>
+#include <linux/fs_parser.h>
+#include <linux/magic.h>
+#include <linux/module.h>
+#include <linux/nls.h>
+#include <linux/statfs.h>
+#include <linux/vbox_utils.h>
+#include "vfsmod.h"
+
+#define VBOXSF_SUPER_MAGIC 0x786f4256 /* 'VBox' little endian */
+
+static const unsigned char VBSF_MOUNT_SIGNATURE[4] = "\000\377\376\375";
+
+static int follow_symlinks;
+module_param(follow_symlinks, int, 0444);
+MODULE_PARM_DESC(follow_symlinks,
+		 "Let host resolve symlinks rather than showing them");
+
+static DEFINE_IDA(vboxsf_bdi_ida);
+static DEFINE_MUTEX(vboxsf_setup_mutex);
+static bool vboxsf_setup_done;
+static struct super_operations vboxsf_super_ops; /* forward declaration */
+static struct kmem_cache *vboxsf_inode_cachep;
+
+static char * const vboxsf_default_nls = CONFIG_NLS_DEFAULT;
+
+enum  { opt_nls, opt_uid, opt_gid, opt_ttl, opt_dmode, opt_fmode,
+	opt_dmask, opt_fmask };
+
+static const struct fs_parameter_spec vboxsf_fs_parameters[] = {
+	fsparam_string	("nls",		opt_nls),
+	fsparam_u32	("uid",		opt_uid),
+	fsparam_u32	("gid",		opt_gid),
+	fsparam_u32	("ttl",		opt_ttl),
+	fsparam_u32oct	("dmode",	opt_dmode),
+	fsparam_u32oct	("fmode",	opt_fmode),
+	fsparam_u32oct	("dmask",	opt_dmask),
+	fsparam_u32oct	("fmask",	opt_fmask),
+	{}
+};
+
+static int vboxsf_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct vboxsf_fs_context *ctx = fc->fs_private;
+	struct fs_parse_result result;
+	kuid_t uid;
+	kgid_t gid;
+	int opt;
+
+	opt = fs_parse(fc, vboxsf_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case opt_nls:
+		if (ctx->nls_name || fc->purpose != FS_CONTEXT_FOR_MOUNT) {
+			vbg_err("vboxsf: Cannot reconfigure nls option\n");
+			return -EINVAL;
+		}
+		ctx->nls_name = param->string;
+		param->string = NULL;
+		break;
+	case opt_uid:
+		uid = make_kuid(current_user_ns(), result.uint_32);
+		if (!uid_valid(uid))
+			return -EINVAL;
+		ctx->o.uid = uid;
+		break;
+	case opt_gid:
+		gid = make_kgid(current_user_ns(), result.uint_32);
+		if (!gid_valid(gid))
+			return -EINVAL;
+		ctx->o.gid = gid;
+		break;
+	case opt_ttl:
+		ctx->o.ttl = msecs_to_jiffies(result.uint_32);
+		break;
+	case opt_dmode:
+		if (result.uint_32 & ~0777)
+			return -EINVAL;
+		ctx->o.dmode = result.uint_32;
+		ctx->o.dmode_set = true;
+		break;
+	case opt_fmode:
+		if (result.uint_32 & ~0777)
+			return -EINVAL;
+		ctx->o.fmode = result.uint_32;
+		ctx->o.fmode_set = true;
+		break;
+	case opt_dmask:
+		if (result.uint_32 & ~07777)
+			return -EINVAL;
+		ctx->o.dmask = result.uint_32;
+		break;
+	case opt_fmask:
+		if (result.uint_32 & ~07777)
+			return -EINVAL;
+		ctx->o.fmask = result.uint_32;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct vboxsf_fs_context *ctx = fc->fs_private;
+	struct shfl_string *folder_name, root_path;
+	struct vboxsf_sbi *sbi;
+	struct dentry *droot;
+	struct inode *iroot;
+	char *nls_name;
+	size_t size;
+	int err;
+
+	if (!fc->source)
+		return -EINVAL;
+
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	sbi->o = ctx->o;
+	idr_init(&sbi->ino_idr);
+	spin_lock_init(&sbi->ino_idr_lock);
+	sbi->next_generation = 1;
+	sbi->bdi_id = -1;
+
+	/* Load nls if not utf8 */
+	nls_name = ctx->nls_name ? ctx->nls_name : vboxsf_default_nls;
+	if (strcmp(nls_name, "utf8") != 0) {
+		if (nls_name == vboxsf_default_nls)
+			sbi->nls = load_nls_default();
+		else
+			sbi->nls = load_nls(nls_name);
+
+		if (!sbi->nls) {
+			vbg_err("vboxsf: Count not load '%s' nls\n", nls_name);
+			err = -EINVAL;
+			goto fail_free;
+		}
+	}
+
+	sbi->bdi_id = ida_simple_get(&vboxsf_bdi_ida, 0, 0, GFP_KERNEL);
+	if (sbi->bdi_id < 0) {
+		err = sbi->bdi_id;
+		goto fail_free;
+	}
+
+	err = super_setup_bdi_name(sb, "vboxsf-%d", sbi->bdi_id);
+	if (err)
+		goto fail_free;
+	sb->s_bdi->ra_pages = 0;
+	sb->s_bdi->io_pages = 0;
+
+	/* Turn source into a shfl_string and map the folder */
+	size = strlen(fc->source) + 1;
+	folder_name = kmalloc(SHFLSTRING_HEADER_SIZE + size, GFP_KERNEL);
+	if (!folder_name) {
+		err = -ENOMEM;
+		goto fail_free;
+	}
+	folder_name->size = size;
+	folder_name->length = size - 1;
+	strlcpy(folder_name->string.utf8, fc->source, size);
+	err = vboxsf_map_folder(folder_name, &sbi->root);
+	kfree(folder_name);
+	if (err) {
+		vbg_err("vboxsf: Host rejected mount of '%s' with error %d\n",
+			fc->source, err);
+		goto fail_free;
+	}
+
+	root_path.length = 1;
+	root_path.size = 2;
+	root_path.string.utf8[0] = '/';
+	root_path.string.utf8[1] = 0;
+	err = vboxsf_stat(sbi, &root_path, &sbi->root_info);
+	if (err)
+		goto fail_unmap;
+
+	sb->s_magic = VBOXSF_SUPER_MAGIC;
+	sb->s_blocksize = 1024;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_op = &vboxsf_super_ops;
+	sb->s_d_op = &vboxsf_dentry_ops;
+
+	iroot = iget_locked(sb, 0);
+	if (!iroot) {
+		err = -ENOMEM;
+		goto fail_unmap;
+	}
+	vboxsf_init_inode(sbi, iroot, &sbi->root_info);
+	unlock_new_inode(iroot);
+
+	droot = d_make_root(iroot);
+	if (!droot) {
+		err = -ENOMEM;
+		goto fail_unmap;
+	}
+
+	sb->s_root = droot;
+	sb->s_fs_info = sbi;
+	return 0;
+
+fail_unmap:
+	vboxsf_unmap_folder(sbi->root);
+fail_free:
+	if (sbi->bdi_id >= 0)
+		ida_simple_remove(&vboxsf_bdi_ida, sbi->bdi_id);
+	if (sbi->nls)
+		unload_nls(sbi->nls);
+	idr_destroy(&sbi->ino_idr);
+	kfree(sbi);
+	return err;
+}
+
+static void vboxsf_inode_init_once(void *data)
+{
+	struct vboxsf_inode *sf_i = data;
+
+	mutex_init(&sf_i->handle_list_mutex);
+	inode_init_once(&sf_i->vfs_inode);
+}
+
+static struct inode *vboxsf_alloc_inode(struct super_block *sb)
+{
+	struct vboxsf_inode *sf_i;
+
+	sf_i = kmem_cache_alloc(vboxsf_inode_cachep, GFP_NOFS);
+	if (!sf_i)
+		return NULL;
+
+	sf_i->force_restat = 0;
+	INIT_LIST_HEAD(&sf_i->handle_list);
+
+	return &sf_i->vfs_inode;
+}
+
+static void vboxsf_free_inode(struct inode *inode)
+{
+	struct vboxsf_sbi *sbi = VBOXSF_SBI(inode->i_sb);
+	unsigned long flags;
+
+	spin_lock_irqsave(&sbi->ino_idr_lock, flags);
+	idr_remove(&sbi->ino_idr, inode->i_ino);
+	spin_unlock_irqrestore(&sbi->ino_idr_lock, flags);
+	kmem_cache_free(vboxsf_inode_cachep, VBOXSF_I(inode));
+}
+
+static void vboxsf_put_super(struct super_block *sb)
+{
+	struct vboxsf_sbi *sbi = VBOXSF_SBI(sb);
+
+	vboxsf_unmap_folder(sbi->root);
+	if (sbi->bdi_id >= 0)
+		ida_simple_remove(&vboxsf_bdi_ida, sbi->bdi_id);
+	if (sbi->nls)
+		unload_nls(sbi->nls);
+
+	/*
+	 * vboxsf_free_inode uses the idr, make sure all delayed rcu free
+	 * inodes are flushed.
+	 */
+	rcu_barrier();
+	idr_destroy(&sbi->ino_idr);
+	kfree(sbi);
+}
+
+static int vboxsf_statfs(struct dentry *dentry, struct kstatfs *stat)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct shfl_volinfo shfl_volinfo;
+	struct vboxsf_sbi *sbi;
+	u32 buf_len;
+	int err;
+
+	sbi = VBOXSF_SBI(sb);
+	buf_len = sizeof(shfl_volinfo);
+	err = vboxsf_fsinfo(sbi->root, 0, SHFL_INFO_GET | SHFL_INFO_VOLUME,
+			    &buf_len, &shfl_volinfo);
+	if (err)
+		return err;
+
+	stat->f_type = VBOXSF_SUPER_MAGIC;
+	stat->f_bsize = shfl_volinfo.bytes_per_allocation_unit;
+
+	do_div(shfl_volinfo.total_allocation_bytes,
+	       shfl_volinfo.bytes_per_allocation_unit);
+	stat->f_blocks = shfl_volinfo.total_allocation_bytes;
+
+	do_div(shfl_volinfo.available_allocation_bytes,
+	       shfl_volinfo.bytes_per_allocation_unit);
+	stat->f_bfree  = shfl_volinfo.available_allocation_bytes;
+	stat->f_bavail = shfl_volinfo.available_allocation_bytes;
+
+	stat->f_files = 1000;
+	/*
+	 * Don't return 0 here since the guest may then think that it is not
+	 * possible to create any more files.
+	 */
+	stat->f_ffree = 1000000;
+	stat->f_fsid.val[0] = 0;
+	stat->f_fsid.val[1] = 0;
+	stat->f_namelen = 255;
+	return 0;
+}
+
+static struct super_operations vboxsf_super_ops = {
+	.alloc_inode	= vboxsf_alloc_inode,
+	.free_inode	= vboxsf_free_inode,
+	.put_super	= vboxsf_put_super,
+	.statfs		= vboxsf_statfs,
+};
+
+static int vboxsf_setup(void)
+{
+	int err;
+
+	mutex_lock(&vboxsf_setup_mutex);
+
+	if (vboxsf_setup_done)
+		goto success;
+
+	vboxsf_inode_cachep =
+		kmem_cache_create("vboxsf_inode_cache",
+				  sizeof(struct vboxsf_inode), 0,
+				  (SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD |
+				   SLAB_ACCOUNT),
+				  vboxsf_inode_init_once);
+	if (!vboxsf_inode_cachep) {
+		err = -ENOMEM;
+		goto fail_nomem;
+	}
+
+	err = vboxsf_connect();
+	if (err) {
+		vbg_err("vboxsf: err %d connecting to guest PCI-device\n", err);
+		vbg_err("vboxsf: make sure you are inside a VirtualBox VM\n");
+		vbg_err("vboxsf: and check dmesg for vboxguest errors\n");
+		goto fail_free_cache;
+	}
+
+	err = vboxsf_set_utf8();
+	if (err) {
+		vbg_err("vboxsf_setutf8 error %d\n", err);
+		goto fail_disconnect;
+	}
+
+	if (!follow_symlinks) {
+		err = vboxsf_set_symlinks();
+		if (err)
+			vbg_warn("vboxsf: Unable to show symlinks: %d\n", err);
+	}
+
+	vboxsf_setup_done = true;
+success:
+	mutex_unlock(&vboxsf_setup_mutex);
+	return 0;
+
+fail_disconnect:
+	vboxsf_disconnect();
+fail_free_cache:
+	kmem_cache_destroy(vboxsf_inode_cachep);
+fail_nomem:
+	mutex_unlock(&vboxsf_setup_mutex);
+	return err;
+}
+
+static int vboxsf_parse_monolithic(struct fs_context *fc, void *data)
+{
+	if (data && !memcmp(data, VBSF_MOUNT_SIGNATURE, 4)) {
+		vbg_err("vboxsf: Old binary mount data not supported, remove obsolete mount.vboxsf and/or update your VBoxService.\n");
+		return -EINVAL;
+	}
+
+	return generic_parse_monolithic(fc, data);
+}
+
+static int vboxsf_get_tree(struct fs_context *fc)
+{
+	int err;
+
+	err = vboxsf_setup();
+	if (err)
+		return err;
+
+	return get_tree_nodev(fc, vboxsf_fill_super);
+}
+
+static int vboxsf_reconfigure(struct fs_context *fc)
+{
+	struct vboxsf_sbi *sbi = VBOXSF_SBI(fc->root->d_sb);
+	struct vboxsf_fs_context *ctx = fc->fs_private;
+	struct inode *iroot = fc->root->d_sb->s_root->d_inode;
+
+	/* Apply changed options to the root inode */
+	sbi->o = ctx->o;
+	vboxsf_init_inode(sbi, iroot, &sbi->root_info);
+
+	return 0;
+}
+
+static void vboxsf_free_fc(struct fs_context *fc)
+{
+	struct vboxsf_fs_context *ctx = fc->fs_private;
+
+	kfree(ctx->nls_name);
+	kfree(ctx);
+}
+
+static const struct fs_context_operations vboxsf_context_ops = {
+	.free			= vboxsf_free_fc,
+	.parse_param		= vboxsf_parse_param,
+	.parse_monolithic	= vboxsf_parse_monolithic,
+	.get_tree		= vboxsf_get_tree,
+	.reconfigure		= vboxsf_reconfigure,
+};
+
+static int vboxsf_init_fs_context(struct fs_context *fc)
+{
+	struct vboxsf_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	current_uid_gid(&ctx->o.uid, &ctx->o.gid);
+
+	fc->fs_private = ctx;
+	fc->ops = &vboxsf_context_ops;
+	return 0;
+}
+
+static struct file_system_type vboxsf_fs_type = {
+	.owner			= THIS_MODULE,
+	.name			= "vboxsf",
+	.init_fs_context	= vboxsf_init_fs_context,
+	.kill_sb		= kill_anon_super
+};
+
+/* Module initialization/finalization handlers */
+static int __init vboxsf_init(void)
+{
+	return register_filesystem(&vboxsf_fs_type);
+}
+
+static void __exit vboxsf_fini(void)
+{
+	unregister_filesystem(&vboxsf_fs_type);
+
+	mutex_lock(&vboxsf_setup_mutex);
+	if (vboxsf_setup_done) {
+		vboxsf_disconnect();
+		/*
+		 * Make sure all delayed rcu free inodes are flushed
+		 * before we destroy the cache.
+		 */
+		rcu_barrier();
+		kmem_cache_destroy(vboxsf_inode_cachep);
+	}
+	mutex_unlock(&vboxsf_setup_mutex);
+}
+
+module_init(vboxsf_init);
+module_exit(vboxsf_fini);
+
+MODULE_DESCRIPTION("Oracle VM VirtualBox Module for Host File System Access");
+MODULE_AUTHOR("Oracle Corporation");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_FS("vboxsf");