diff options
| -rw-r--r-- | fs/configfs/dir.c | 42 |
1 files changed, 33 insertions, 9 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index a89058b39884..7a8db78a91d2 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -1100,7 +1100,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) struct configfs_subsystem *subsys; struct configfs_dirent *sd; struct config_item_type *type; - struct module *owner = NULL; + struct module *subsys_owner = NULL, *new_item_owner = NULL; char *name; if (dentry->d_parent == configfs_sb->s_root) { @@ -1137,10 +1137,25 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) goto out_put; } + /* + * The subsystem may belong to a different module than the item + * being created. We don't want to safely pin the new item but + * fail to pin the subsystem it sits under. + */ + if (!subsys->su_group.cg_item.ci_type) { + ret = -EINVAL; + goto out_put; + } + subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; + if (!try_module_get(subsys_owner)) { + ret = -EINVAL; + goto out_put; + } + name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); if (!name) { ret = -ENOMEM; - goto out_put; + goto out_subsys_put; } snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); @@ -1172,7 +1187,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) * If ret != 0, then link_obj() was never called. * There are no extra references to clean up. */ - goto out_put; + goto out_subsys_put; } /* @@ -1186,8 +1201,8 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) goto out_unlink; } - owner = type->ct_owner; - if (!try_module_get(owner)) { + new_item_owner = type->ct_owner; + if (!try_module_get(new_item_owner)) { ret = -EINVAL; goto out_unlink; } @@ -1236,9 +1251,13 @@ out_unlink: mutex_unlock(&subsys->su_mutex); if (module_got) - module_put(owner); + module_put(new_item_owner); } +out_subsys_put: + if (ret) + module_put(subsys_owner); + out_put: /* * link_obj()/link_group() took a reference from child->parent, @@ -1257,7 +1276,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) struct config_item *item; struct configfs_subsystem *subsys; struct configfs_dirent *sd; - struct module *owner = NULL; + struct module *subsys_owner = NULL, *dead_item_owner = NULL; int ret; if (dentry->d_parent == configfs_sb->s_root) @@ -1284,6 +1303,10 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) return -EINVAL; } + /* configfs_mkdir() shouldn't have allowed this */ + BUG_ON(!subsys->su_group.cg_item.ci_type); + subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; + /* * Ensure that no racing symlink() will make detach_prep() fail while * the new link is temporarily attached @@ -1321,7 +1344,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) config_item_put(parent_item); if (item->ci_type) - owner = item->ci_type->ct_owner; + dead_item_owner = item->ci_type->ct_owner; if (sd->s_type & CONFIGFS_USET_DIR) { configfs_detach_group(item); @@ -1343,7 +1366,8 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) /* Drop our reference from above */ config_item_put(item); - module_put(owner); + module_put(dead_item_owner); + module_put(subsys_owner); return 0; } |