diff options
| -rw-r--r-- | fs/configfs/configfs_internal.h | 2 | ||||
| -rw-r--r-- | fs/configfs/dir.c | 91 | ||||
| -rw-r--r-- | fs/configfs/symlink.c | 15 |
3 files changed, 103 insertions, 5 deletions
diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h index 5f61b26eba9..762d287123c 100644 --- a/fs/configfs/configfs_internal.h +++ b/fs/configfs/configfs_internal.h @@ -49,6 +49,7 @@ struct configfs_dirent { #define CONFIGFS_USET_DEFAULT 0x0080 #define CONFIGFS_USET_DROPPING 0x0100 #define CONFIGFS_USET_IN_MKDIR 0x0200 +#define CONFIGFS_USET_CREATING 0x0400 #define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR) extern struct mutex configfs_symlink_mutex; @@ -67,6 +68,7 @@ extern void configfs_inode_exit(void); extern int configfs_create_file(struct config_item *, const struct configfs_attribute *); extern int configfs_make_dirent(struct configfs_dirent *, struct dentry *, void *, umode_t, int); +extern int configfs_dirent_is_ready(struct configfs_dirent *); extern int configfs_add_file(struct dentry *, const struct configfs_attribute *, int); extern void configfs_hash_and_remove(struct dentry * dir, const char * name); diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 4e228c80fe9..647499a3479 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -185,7 +185,7 @@ static int create_dir(struct config_item * k, struct dentry * p, error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); if (!error) error = configfs_make_dirent(p->d_fsdata, d, k, mode, - CONFIGFS_DIR); + CONFIGFS_DIR | CONFIGFS_USET_CREATING); if (!error) { error = configfs_create(d, mode, init_dir); if (!error) { @@ -209,6 +209,9 @@ static int create_dir(struct config_item * k, struct dentry * p, * configfs_create_dir - create a directory for an config_item. * @item: config_itemwe're creating directory for. * @dentry: config_item's dentry. + * + * Note: user-created entries won't be allowed under this new directory + * until it is validated by configfs_dir_set_ready() */ static int configfs_create_dir(struct config_item * item, struct dentry *dentry) @@ -231,6 +234,44 @@ static int configfs_create_dir(struct config_item * item, struct dentry *dentry) return error; } +/* + * Allow userspace to create new entries under a new directory created with + * configfs_create_dir(), and under all of its chidlren directories recursively. + * @sd configfs_dirent of the new directory to validate + * + * Caller must hold configfs_dirent_lock. + */ +static void configfs_dir_set_ready(struct configfs_dirent *sd) +{ + struct configfs_dirent *child_sd; + + sd->s_type &= ~CONFIGFS_USET_CREATING; + list_for_each_entry(child_sd, &sd->s_children, s_sibling) + if (child_sd->s_type & CONFIGFS_USET_CREATING) + configfs_dir_set_ready(child_sd); +} + +/* + * Check that a directory does not belong to a directory hierarchy being + * attached and not validated yet. + * @sd configfs_dirent of the directory to check + * + * @return non-zero iff the directory was validated + * + * Note: takes configfs_dirent_lock, so the result may change from false to true + * in two consecutive calls, but never from true to false. + */ +int configfs_dirent_is_ready(struct configfs_dirent *sd) +{ + int ret; + + spin_lock(&configfs_dirent_lock); + ret = !(sd->s_type & CONFIGFS_USET_CREATING); + spin_unlock(&configfs_dirent_lock); + + return ret; +} + int configfs_create_link(struct configfs_symlink *sl, struct dentry *parent, struct dentry *dentry) @@ -330,7 +371,19 @@ static struct dentry * configfs_lookup(struct inode *dir, struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; struct configfs_dirent * sd; int found = 0; - int err = 0; + int err; + + /* + * Fake invisibility if dir belongs to a group/default groups hierarchy + * being attached + * + * This forbids userspace to read/write attributes of items which may + * not complete their initialization, since the dentries of the + * attributes won't be instantiated. + */ + err = -ENOENT; + if (!configfs_dirent_is_ready(parent_sd)) + goto out; list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { if (sd->s_type & CONFIGFS_NOT_PINNED) { @@ -353,6 +406,7 @@ static struct dentry * configfs_lookup(struct inode *dir, return simple_lookup(dir, dentry, nd); } +out: return ERR_PTR(err); } @@ -1044,6 +1098,16 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) } sd = dentry->d_parent->d_fsdata; + + /* + * Fake invisibility if dir belongs to a group/default groups hierarchy + * being attached + */ + if (!configfs_dirent_is_ready(sd)) { + ret = -ENOENT; + goto out; + } + if (!(sd->s_type & CONFIGFS_USET_DIR)) { ret = -EPERM; goto out; @@ -1142,6 +1206,8 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) spin_lock(&configfs_dirent_lock); sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; + if (!ret) + configfs_dir_set_ready(dentry->d_fsdata); spin_unlock(&configfs_dirent_lock); out_unlink: @@ -1322,13 +1388,24 @@ static int configfs_dir_open(struct inode *inode, struct file *file) { struct dentry * dentry = file->f_path.dentry; struct configfs_dirent * parent_sd = dentry->d_fsdata; + int err; mutex_lock(&dentry->d_inode->i_mutex); - file->private_data = configfs_new_dirent(parent_sd, NULL); + /* + * Fake invisibility if dir belongs to a group/default groups hierarchy + * being attached + */ + err = -ENOENT; + if (configfs_dirent_is_ready(parent_sd)) { + file->private_data = configfs_new_dirent(parent_sd, NULL); + if (IS_ERR(file->private_data)) + err = PTR_ERR(file->private_data); + else + err = 0; + } mutex_unlock(&dentry->d_inode->i_mutex); - return IS_ERR(file->private_data) ? PTR_ERR(file->private_data) : 0; - + return err; } static int configfs_dir_close(struct inode *inode, struct file *file) @@ -1499,6 +1576,10 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) if (err) { d_delete(dentry); dput(dentry); + } else { + spin_lock(&configfs_dirent_lock); + configfs_dir_set_ready(dentry->d_fsdata); + spin_unlock(&configfs_dirent_lock); } } diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c index 61a886dbd60..bf74973b049 100644 --- a/fs/configfs/symlink.c +++ b/fs/configfs/symlink.c @@ -76,6 +76,9 @@ static int create_link(struct config_item *parent_item, struct configfs_symlink *sl; int ret; + ret = -ENOENT; + if (!configfs_dirent_is_ready(target_sd)) + goto out; ret = -ENOMEM; sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL); if (sl) { @@ -100,6 +103,7 @@ static int create_link(struct config_item *parent_item, } } +out: return ret; } @@ -129,6 +133,7 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna { int ret; struct nameidata nd; + struct configfs_dirent *sd; struct config_item *parent_item; struct config_item *target_item; struct config_item_type *type; @@ -137,9 +142,19 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna if (dentry->d_parent == configfs_sb->s_root) goto out; + sd = dentry->d_parent->d_fsdata; + /* + * Fake invisibility if dir belongs to a group/default groups hierarchy + * being attached + */ + ret = -ENOENT; + if (!configfs_dirent_is_ready(sd)) + goto out; + parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; + ret = -EPERM; if (!type || !type->ct_item_ops || !type->ct_item_ops->allow_link) goto out_put; |