diff options
| -rw-r--r-- | fs/mount.h | 5 | ||||
| -rw-r--r-- | fs/namespace.c | 74 |
2 files changed, 40 insertions, 39 deletions
diff --git a/fs/mount.h b/fs/mount.h index f39bc9da4d73..6250de544760 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -146,3 +146,8 @@ static inline bool is_local_mountpoint(struct dentry *dentry) return __is_local_mountpoint(dentry); } + +static inline bool is_anon_ns(struct mnt_namespace *ns) +{ + return ns->seq == 0; +} diff --git a/fs/namespace.c b/fs/namespace.c index 9ed2f2930dfd..f0b8a8ca08df 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2873,7 +2873,8 @@ static void dec_mnt_namespaces(struct ucounts *ucounts) static void free_mnt_ns(struct mnt_namespace *ns) { - ns_free_inum(&ns->ns); + if (!is_anon_ns(ns)) + ns_free_inum(&ns->ns); dec_mnt_namespaces(ns->ucounts); put_user_ns(ns->user_ns); kfree(ns); @@ -2888,7 +2889,7 @@ static void free_mnt_ns(struct mnt_namespace *ns) */ static atomic64_t mnt_ns_seq = ATOMIC64_INIT(1); -static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns) +static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool anon) { struct mnt_namespace *new_ns; struct ucounts *ucounts; @@ -2898,28 +2899,27 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns) if (!ucounts) return ERR_PTR(-ENOSPC); - new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL); + new_ns = kzalloc(sizeof(struct mnt_namespace), GFP_KERNEL); if (!new_ns) { dec_mnt_namespaces(ucounts); return ERR_PTR(-ENOMEM); } - ret = ns_alloc_inum(&new_ns->ns); - if (ret) { - kfree(new_ns); - dec_mnt_namespaces(ucounts); - return ERR_PTR(ret); + if (!anon) { + ret = ns_alloc_inum(&new_ns->ns); + if (ret) { + kfree(new_ns); + dec_mnt_namespaces(ucounts); + return ERR_PTR(ret); + } } new_ns->ns.ops = &mntns_operations; - new_ns->seq = atomic64_add_return(1, &mnt_ns_seq); + if (!anon) + new_ns->seq = atomic64_add_return(1, &mnt_ns_seq); atomic_set(&new_ns->count, 1); - new_ns->root = NULL; INIT_LIST_HEAD(&new_ns->list); init_waitqueue_head(&new_ns->poll); - new_ns->event = 0; new_ns->user_ns = get_user_ns(user_ns); new_ns->ucounts = ucounts; - new_ns->mounts = 0; - new_ns->pending_mounts = 0; return new_ns; } @@ -2943,7 +2943,7 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns, old = ns->root; - new_ns = alloc_mnt_ns(user_ns); + new_ns = alloc_mnt_ns(user_ns, false); if (IS_ERR(new_ns)) return new_ns; @@ -3003,37 +3003,25 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns, return new_ns; } -/** - * create_mnt_ns - creates a private namespace and adds a root filesystem - * @mnt: pointer to the new root filesystem mountpoint - */ -static struct mnt_namespace *create_mnt_ns(struct vfsmount *m) -{ - struct mnt_namespace *new_ns = alloc_mnt_ns(&init_user_ns); - if (!IS_ERR(new_ns)) { - struct mount *mnt = real_mount(m); - mnt->mnt_ns = new_ns; - new_ns->root = mnt; - new_ns->mounts++; - list_add(&mnt->mnt_list, &new_ns->list); - } else { - mntput(m); - } - return new_ns; -} - -struct dentry *mount_subtree(struct vfsmount *mnt, const char *name) +struct dentry *mount_subtree(struct vfsmount *m, const char *name) { + struct mount *mnt = real_mount(m); struct mnt_namespace *ns; struct super_block *s; struct path path; int err; - ns = create_mnt_ns(mnt); - if (IS_ERR(ns)) + ns = alloc_mnt_ns(&init_user_ns, true); + if (IS_ERR(ns)) { + mntput(m); return ERR_CAST(ns); + } + mnt->mnt_ns = ns; + ns->root = mnt; + ns->mounts++; + list_add(&mnt->mnt_list, &ns->list); - err = vfs_path_lookup(mnt->mnt_root, mnt, + err = vfs_path_lookup(m->mnt_root, m, name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path); put_mnt_ns(ns); @@ -3243,6 +3231,7 @@ out0: static void __init init_mount_tree(void) { struct vfsmount *mnt; + struct mount *m; struct mnt_namespace *ns; struct path root; struct file_system_type *type; @@ -3255,10 +3244,14 @@ static void __init init_mount_tree(void) if (IS_ERR(mnt)) panic("Can't create rootfs"); - ns = create_mnt_ns(mnt); + ns = alloc_mnt_ns(&init_user_ns, false); if (IS_ERR(ns)) panic("Can't allocate initial namespace"); - + m = real_mount(mnt); + m->mnt_ns = ns; + ns->root = m; + ns->mounts = 1; + list_add(&m->mnt_list, &ns->list); init_task.nsproxy->mnt_ns = ns; get_mnt_ns(ns); @@ -3499,6 +3492,9 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) return -EPERM; + if (is_anon_ns(mnt_ns)) + return -EINVAL; + if (fs->users != 1) return -EINVAL; |