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- // 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_IMPORT_NS(ANDROID_GKI_VFS_EXPORT_ONLY);
- MODULE_ALIAS_FS("vboxsf");
|