diff options
Diffstat (limited to 'fs')
-rw-r--r-- | fs/configfs/mount.c | 10 | ||||
-rw-r--r-- | fs/dcache.c | 11 | ||||
-rw-r--r-- | fs/debugfs/inode.c | 11 | ||||
-rw-r--r-- | fs/fuse/inode.c | 9 | ||||
-rw-r--r-- | fs/kernfs/dir.c | 38 | ||||
-rw-r--r-- | fs/kernfs/inode.c | 2 | ||||
-rw-r--r-- | fs/libfs.c | 95 | ||||
-rw-r--r-- | fs/namespace.c | 39 | ||||
-rw-r--r-- | fs/proc/generic.c | 23 | ||||
-rw-r--r-- | fs/proc/inode.c | 4 | ||||
-rw-r--r-- | fs/proc/internal.h | 6 | ||||
-rw-r--r-- | fs/proc/proc_sysctl.c | 37 | ||||
-rw-r--r-- | fs/proc/root.c | 9 | ||||
-rw-r--r-- | fs/pstore/inode.c | 12 | ||||
-rw-r--r-- | fs/sysfs/dir.c | 34 | ||||
-rw-r--r-- | fs/sysfs/mount.c | 5 | ||||
-rw-r--r-- | fs/tracefs/inode.c | 6 |
17 files changed, 292 insertions, 59 deletions
diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c index 5373567..a8f3b58 100644 --- a/fs/configfs/mount.c +++ b/fs/configfs/mount.c @@ -129,8 +129,6 @@ void configfs_release_fs(void) } -static struct kobject *config_kobj; - static int __init configfs_init(void) { int err = -ENOMEM; @@ -141,8 +139,8 @@ static int __init configfs_init(void) if (!configfs_dir_cachep) goto out; - config_kobj = kobject_create_and_add("config", kernel_kobj); - if (!config_kobj) + err = sysfs_create_mount_point(kernel_kobj, "config"); + if (err) goto out2; err = register_filesystem(&configfs_fs_type); @@ -152,7 +150,7 @@ static int __init configfs_init(void) return 0; out3: pr_err("Unable to register filesystem!\n"); - kobject_put(config_kobj); + sysfs_remove_mount_point(kernel_kobj, "config"); out2: kmem_cache_destroy(configfs_dir_cachep); configfs_dir_cachep = NULL; @@ -163,7 +161,7 @@ out: static void __exit configfs_exit(void) { unregister_filesystem(&configfs_fs_type); - kobject_put(config_kobj); + sysfs_remove_mount_point(kernel_kobj, "config"); kmem_cache_destroy(configfs_dir_cachep); configfs_dir_cachep = NULL; } diff --git a/fs/dcache.c b/fs/dcache.c index 592c4b5..910968b 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2927,17 +2927,6 @@ restart: vfsmnt = &mnt->mnt; continue; } - /* - * Filesystems needing to implement special "root names" - * should do so with ->d_dname() - */ - if (IS_ROOT(dentry) && - (dentry->d_name.len != 1 || - dentry->d_name.name[0] != '/')) { - WARN(1, "Root dentry has weird name <%.*s>\n", - (int) dentry->d_name.len, - dentry->d_name.name); - } if (!error) error = is_mounted(vfsmnt) ? 1 : 2; break; diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 7eaec88..d6d1cf0 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -716,20 +716,17 @@ bool debugfs_initialized(void) } EXPORT_SYMBOL_GPL(debugfs_initialized); - -static struct kobject *debug_kobj; - static int __init debugfs_init(void) { int retval; - debug_kobj = kobject_create_and_add("debug", kernel_kobj); - if (!debug_kobj) - return -EINVAL; + retval = sysfs_create_mount_point(kernel_kobj, "debug"); + if (retval) + return retval; retval = register_filesystem(&debug_fs_type); if (retval) - kobject_put(debug_kobj); + sysfs_remove_mount_point(kernel_kobj, "debug"); else debugfs_registered = true; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index ac81f48..2913db2 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1294,7 +1294,6 @@ static void fuse_fs_cleanup(void) } static struct kobject *fuse_kobj; -static struct kobject *connections_kobj; static int fuse_sysfs_init(void) { @@ -1306,11 +1305,9 @@ static int fuse_sysfs_init(void) goto out_err; } - connections_kobj = kobject_create_and_add("connections", fuse_kobj); - if (!connections_kobj) { - err = -ENOMEM; + err = sysfs_create_mount_point(fuse_kobj, "connections"); + if (err) goto out_fuse_unregister; - } return 0; @@ -1322,7 +1319,7 @@ static int fuse_sysfs_init(void) static void fuse_sysfs_cleanup(void) { - kobject_put(connections_kobj); + sysfs_remove_mount_point(fuse_kobj, "connections"); kobject_put(fuse_kobj); } diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index fffca95..2d48d28 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -592,6 +592,9 @@ int kernfs_add_one(struct kernfs_node *kn) goto out_unlock; ret = -ENOENT; + if (parent->flags & KERNFS_EMPTY_DIR) + goto out_unlock; + if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) goto out_unlock; @@ -783,6 +786,38 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, return ERR_PTR(rc); } +/** + * kernfs_create_empty_dir - create an always empty directory + * @parent: parent in which to create a new directory + * @name: name of the new directory + * + * Returns the created node on success, ERR_PTR() value on failure. + */ +struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, + const char *name) +{ + struct kernfs_node *kn; + int rc; + + /* allocate */ + kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR); + if (!kn) + return ERR_PTR(-ENOMEM); + + kn->flags |= KERNFS_EMPTY_DIR; + kn->dir.root = parent->dir.root; + kn->ns = NULL; + kn->priv = NULL; + + /* link in */ + rc = kernfs_add_one(kn); + if (!rc) + return kn; + + kernfs_put(kn); + return ERR_PTR(rc); +} + static struct dentry *kernfs_iop_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) @@ -1254,7 +1289,8 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, mutex_lock(&kernfs_mutex); error = -ENOENT; - if (!kernfs_active(kn) || !kernfs_active(new_parent)) + if (!kernfs_active(kn) || !kernfs_active(new_parent) || + (new_parent->flags & KERNFS_EMPTY_DIR)) goto out; error = 0; diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index 2da8493..756dd56 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -296,6 +296,8 @@ static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode) case KERNFS_DIR: inode->i_op = &kernfs_dir_iops; inode->i_fop = &kernfs_dir_fops; + if (kn->flags & KERNFS_EMPTY_DIR) + make_empty_dir_inode(inode); break; case KERNFS_FILE: inode->i_size = kn->attr.size; @@ -1108,3 +1108,98 @@ const struct inode_operations simple_symlink_inode_operations = { .readlink = generic_readlink }; EXPORT_SYMBOL(simple_symlink_inode_operations); + +/* + * Operations for a permanently empty directory. + */ +static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) +{ + return ERR_PTR(-ENOENT); +} + +static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, + struct kstat *stat) +{ + struct inode *inode = d_inode(dentry); + generic_fillattr(inode, stat); + return 0; +} + +static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) +{ + return -EPERM; +} + +static int empty_dir_setxattr(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags) +{ + return -EOPNOTSUPP; +} + +static ssize_t empty_dir_getxattr(struct dentry *dentry, const char *name, + void *value, size_t size) +{ + return -EOPNOTSUPP; +} + +static int empty_dir_removexattr(struct dentry *dentry, const char *name) +{ + return -EOPNOTSUPP; +} + +static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) +{ + return -EOPNOTSUPP; +} + +static const struct inode_operations empty_dir_inode_operations = { + .lookup = empty_dir_lookup, + .permission = generic_permission, + .setattr = empty_dir_setattr, + .getattr = empty_dir_getattr, + .setxattr = empty_dir_setxattr, + .getxattr = empty_dir_getxattr, + .removexattr = empty_dir_removexattr, + .listxattr = empty_dir_listxattr, +}; + +static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) +{ + /* An empty directory has two entries . and .. at offsets 0 and 1 */ + return generic_file_llseek_size(file, offset, whence, 2, 2); +} + +static int empty_dir_readdir(struct file *file, struct dir_context *ctx) +{ + dir_emit_dots(file, ctx); + return 0; +} + +static const struct file_operations empty_dir_operations = { + .llseek = empty_dir_llseek, + .read = generic_read_dir, + .iterate = empty_dir_readdir, + .fsync = noop_fsync, +}; + + +void make_empty_dir_inode(struct inode *inode) +{ + set_nlink(inode, 2); + inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; + inode->i_uid = GLOBAL_ROOT_UID; + inode->i_gid = GLOBAL_ROOT_GID; + inode->i_rdev = 0; + inode->i_size = 2; + inode->i_blkbits = PAGE_SHIFT; + inode->i_blocks = 0; + + inode->i_op = &empty_dir_inode_operations; + inode->i_fop = &empty_dir_operations; +} + +bool is_empty_dir_inode(struct inode *inode) +{ + return (inode->i_fop == &empty_dir_operations) && + (inode->i_op == &empty_dir_inode_operations); +} diff --git a/fs/namespace.c b/fs/namespace.c index e99f1f4..c7cb8a5 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2343,6 +2343,8 @@ unlock: return err; } +static bool fs_fully_visible(struct file_system_type *fs_type, int *new_mnt_flags); + /* * create a new mount for userspace and request it to be added into the * namespace's tree @@ -2374,6 +2376,10 @@ static int do_new_mount(struct path *path, const char *fstype, int flags, flags |= MS_NODEV; mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV; } + if (type->fs_flags & FS_USERNS_VISIBLE) { + if (!fs_fully_visible(type, &mnt_flags)) + return -EPERM; + } } mnt = vfs_kern_mount(type, flags, name, data); @@ -3175,9 +3181,10 @@ bool current_chrooted(void) return chrooted; } -bool fs_fully_visible(struct file_system_type *type) +static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags) { struct mnt_namespace *ns = current->nsproxy->mnt_ns; + int new_flags = *new_mnt_flags; struct mount *mnt; bool visible = false; @@ -3196,16 +3203,36 @@ bool fs_fully_visible(struct file_system_type *type) if (mnt->mnt.mnt_root != mnt->mnt.mnt_sb->s_root) continue; - /* This mount is not fully visible if there are any child mounts - * that cover anything except for empty directories. + /* Verify the mount flags are equal to or more permissive + * than the proposed new mount. + */ + if ((mnt->mnt.mnt_flags & MNT_LOCK_READONLY) && + !(new_flags & MNT_READONLY)) + continue; + if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) && + !(new_flags & MNT_NODEV)) + continue; + if ((mnt->mnt.mnt_flags & MNT_LOCK_ATIME) && + ((mnt->mnt.mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK))) + continue; + + /* This mount is not fully visible if there are any + * locked child mounts that cover anything except for + * empty directories. */ list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) { struct inode *inode = child->mnt_mountpoint->d_inode; - if (!S_ISDIR(inode->i_mode)) - goto next; - if (inode->i_nlink > 2) + /* Only worry about locked mounts */ + if (!(mnt->mnt.mnt_flags & MNT_LOCKED)) + continue; + /* Is the directory permanetly empty? */ + if (!is_empty_dir_inode(inode)) goto next; } + /* Preserve the locked attributes */ + *new_mnt_flags |= mnt->mnt.mnt_flags & (MNT_LOCK_READONLY | \ + MNT_LOCK_NODEV | \ + MNT_LOCK_ATIME); visible = true; goto found; next: ; diff --git a/fs/proc/generic.c b/fs/proc/generic.c index df6327a..e5dee5c 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -373,6 +373,10 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, WARN(1, "create '/proc/%s' by hand\n", qstr.name); return NULL; } + if (is_empty_pde(*parent)) { + WARN(1, "attempt to add to permanently empty directory"); + return NULL; + } ent = kzalloc(sizeof(struct proc_dir_entry) + qstr.len + 1, GFP_KERNEL); if (!ent) @@ -455,6 +459,25 @@ struct proc_dir_entry *proc_mkdir(const char *name, } EXPORT_SYMBOL(proc_mkdir); +struct proc_dir_entry *proc_create_mount_point(const char *name) +{ + umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO; + struct proc_dir_entry *ent, *parent = NULL; + + ent = __proc_create(&parent, name, mode, 2); + if (ent) { + ent->data = NULL; + ent->proc_fops = NULL; + ent->proc_iops = NULL; + if (proc_register(parent, ent) < 0) { + kfree(ent); + parent->nlink--; + ent = NULL; + } + } + return ent; +} + struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, struct proc_dir_entry *parent, const struct file_operations *proc_fops, diff --git a/fs/proc/inode.c b/fs/proc/inode.c index afe232b..bd95b9f 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -422,6 +422,10 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; PROC_I(inode)->pde = de; + if (is_empty_pde(de)) { + make_empty_dir_inode(inode); + return inode; + } if (de->mode) { inode->i_mode = de->mode; inode->i_uid = de->uid; diff --git a/fs/proc/internal.h b/fs/proc/internal.h index c835b94..aa27810 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -191,6 +191,12 @@ static inline struct proc_dir_entry *pde_get(struct proc_dir_entry *pde) } extern void pde_put(struct proc_dir_entry *); +static inline bool is_empty_pde(const struct proc_dir_entry *pde) +{ + return S_ISDIR(pde->mode) && !pde->proc_iops; +} +struct proc_dir_entry *proc_create_mount_point(const char *name); + /* * inode.c */ diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index fea2561..fdda62e 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -19,6 +19,28 @@ static const struct inode_operations proc_sys_inode_operations; static const struct file_operations proc_sys_dir_file_operations; static const struct inode_operations proc_sys_dir_operations; +/* Support for permanently empty directories */ + +struct ctl_table sysctl_mount_point[] = { + { } +}; + +static bool is_empty_dir(struct ctl_table_header *head) +{ + return head->ctl_table[0].child == sysctl_mount_point; +} + +static void set_empty_dir(struct ctl_dir *dir) +{ + dir->header.ctl_table[0].child = sysctl_mount_point; +} + +static void clear_empty_dir(struct ctl_dir *dir) + +{ + dir->header.ctl_table[0].child = NULL; +} + void proc_sys_poll_notify(struct ctl_table_poll *poll) { if (!poll) @@ -187,6 +209,17 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) struct ctl_table *entry; int err; + /* Is this a permanently empty directory? */ + if (is_empty_dir(&dir->header)) + return -EROFS; + + /* Am I creating a permanently empty directory? */ + if (header->ctl_table == sysctl_mount_point) { + if (!RB_EMPTY_ROOT(&dir->root)) + return -EINVAL; + set_empty_dir(dir); + } + dir->header.nreg++; header->parent = dir; err = insert_links(header); @@ -202,6 +235,8 @@ fail: erase_header(header); put_links(header); fail_links: + if (header->ctl_table == sysctl_mount_point) + clear_empty_dir(dir); header->parent = NULL; drop_sysctl_table(&dir->header); return err; @@ -419,6 +454,8 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, inode->i_mode |= S_IFDIR; inode->i_op = &proc_sys_dir_operations; inode->i_fop = &proc_sys_dir_file_operations; + if (is_empty_dir(head)) + make_empty_dir_inode(inode); } out: return inode; diff --git a/fs/proc/root.c b/fs/proc/root.c index b7fa4bf..68feb0f 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -112,9 +112,6 @@ static struct dentry *proc_mount(struct file_system_type *fs_type, ns = task_active_pid_ns(current); options = data; - if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type)) - return ERR_PTR(-EPERM); - /* Does the mounter have privilege over the pid namespace? */ if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); @@ -159,7 +156,7 @@ static struct file_system_type proc_fs_type = { .name = "proc", .mount = proc_mount, .kill_sb = proc_kill_sb, - .fs_flags = FS_USERNS_MOUNT, + .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT, }; void __init proc_root_init(void) @@ -182,10 +179,10 @@ void __init proc_root_init(void) #endif proc_mkdir("fs", NULL); proc_mkdir("driver", NULL); - proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */ + proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */ #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) /* just give it a mountpoint */ - proc_mkdir("openprom", NULL); + proc_create_mount_point("openprom"); #endif proc_tty_init(); proc_mkdir("bus", NULL); diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index dc43b5f..3adcc46 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -461,22 +461,18 @@ static struct file_system_type pstore_fs_type = { .kill_sb = pstore_kill_sb, }; -static struct kobject *pstore_kobj; - static int __init init_pstore_fs(void) { - int err = 0; + int err; /* Create a convenient mount point for people to access pstore */ - pstore_kobj = kobject_create_and_add("pstore", fs_kobj); - if (!pstore_kobj) { - err = -ENOMEM; + err = sysfs_create_mount_point(fs_kobj, "pstore"); + if (err) goto out; - } err = register_filesystem(&pstore_fs_type); if (err < 0) - kobject_put(pstore_kobj); + sysfs_remove_mount_point(fs_kobj, "pstore"); out: return err; diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 0b45ff4..94374e4 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -121,3 +121,37 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj, return kernfs_rename_ns(kn, new_parent, kn->name, new_ns); } + +/** + * sysfs_create_mount_point - create an always empty directory + * @parent_kobj: kobject that will contain this always empty directory + * @name: The name of the always empty directory to add + */ +int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name) +{ + struct kernfs_node *kn, *parent = parent_kobj->sd; + + kn = kernfs_create_empty_dir(parent, name); + if (IS_ERR(kn)) { + if (PTR_ERR(kn) == -EEXIST) + sysfs_warn_dup(parent, name); + return PTR_ERR(kn); + } + + return 0; +} +EXPORT_SYMBOL_GPL(sysfs_create_mount_point); + +/** + * sysfs_remove_mount_point - remove an always empty directory. + * @parent_kobj: kobject that will contain this always empty directory + * @name: The name of the always empty directory to remove + * + */ +void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name) +{ + struct kernfs_node *parent = parent_kobj->sd; + + kernfs_remove_by_name_ns(parent, name, NULL); +} +EXPORT_SYMBOL_GPL(sysfs_remove_mount_point); diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 8a49486..1c6ac6f 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -31,9 +31,6 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, bool new_sb; if (!(flags & MS_KERNMOUNT)) { - if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type)) - return ERR_PTR(-EPERM); - if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET)) return ERR_PTR(-EPERM); } @@ -58,7 +55,7 @@ static struct file_system_type sysfs_fs_type = { .name = "sysfs", .mount = sysfs_mount, .kill_sb = sysfs_kill_sb, - .fs_flags = FS_USERNS_MOUNT, + .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT, }; int __init sysfs_init(void) diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index d92bdf3..a43df11 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -631,14 +631,12 @@ bool tracefs_initialized(void) return tracefs_registered; } -static struct kobject *trace_kobj; - static int __init tracefs_init(void) { int retval; - trace_kobj = kobject_create_and_add("tracing", kernel_kobj); - if (!trace_kobj) + retval = sysfs_create_mount_point(kernel_kobj, "tracing"); + if (retval) return -EINVAL; retval = register_filesystem(&trace_fs_type); |