diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 206 |
1 files changed, 89 insertions, 117 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index d82910f33dc4..c58674a20cad 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -132,16 +132,6 @@ EXPORT_SYMBOL_GPL(fs_kobj); */ __cacheline_aligned_in_smp DEFINE_SEQLOCK(mount_lock); -static inline struct mnt_namespace *node_to_mnt_ns(const struct rb_node *node) -{ - struct ns_common *ns; - - if (!node) - return NULL; - ns = rb_entry(node, struct ns_common, ns_tree_node); - return container_of(ns, struct mnt_namespace, ns); -} - static void mnt_ns_release(struct mnt_namespace *ns) { /* keep alive for {list,stat}mount() */ @@ -151,7 +141,8 @@ static void mnt_ns_release(struct mnt_namespace *ns) kfree(ns); } } -DEFINE_FREE(mnt_ns_release, struct mnt_namespace *, if (_T) mnt_ns_release(_T)) +DEFINE_FREE(mnt_ns_release, struct mnt_namespace *, + if (!IS_ERR(_T)) mnt_ns_release(_T)) static void mnt_ns_release_rcu(struct rcu_head *rcu) { @@ -1345,26 +1336,12 @@ static void delayed_mntput(struct work_struct *unused) } static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput); -static void mntput_no_expire(struct mount *mnt) +static void noinline mntput_no_expire_slowpath(struct mount *mnt) { LIST_HEAD(list); int count; - rcu_read_lock(); - if (likely(READ_ONCE(mnt->mnt_ns))) { - /* - * Since we don't do lock_mount_hash() here, - * ->mnt_ns can change under us. However, if it's - * non-NULL, then there's a reference that won't - * be dropped until after an RCU delay done after - * turning ->mnt_ns NULL. So if we observe it - * non-NULL under rcu_read_lock(), the reference - * we are dropping is not the final one. - */ - mnt_add_count(mnt, -1); - rcu_read_unlock(); - return; - } + VFS_BUG_ON(mnt->mnt_ns); lock_mount_hash(); /* * make sure that if __legitimize_mnt() has not seen us grab @@ -1415,6 +1392,26 @@ static void mntput_no_expire(struct mount *mnt) cleanup_mnt(mnt); } +static void mntput_no_expire(struct mount *mnt) +{ + rcu_read_lock(); + if (likely(READ_ONCE(mnt->mnt_ns))) { + /* + * Since we don't do lock_mount_hash() here, + * ->mnt_ns can change under us. However, if it's + * non-NULL, then there's a reference that won't + * be dropped until after an RCU delay done after + * turning ->mnt_ns NULL. So if we observe it + * non-NULL under rcu_read_lock(), the reference + * we are dropping is not the final one. + */ + mnt_add_count(mnt, -1); + rcu_read_unlock(); + return; + } + mntput_no_expire_slowpath(mnt); +} + void mntput(struct vfsmount *mnt) { if (mnt) { @@ -3103,19 +3100,7 @@ static struct file *vfs_open_tree(int dfd, const char __user *filename, unsigned SYSCALL_DEFINE3(open_tree, int, dfd, const char __user *, filename, unsigned, flags) { - int fd; - struct file *file __free(fput) = NULL; - - file = vfs_open_tree(dfd, filename, flags); - if (IS_ERR(file)) - return PTR_ERR(file); - - fd = get_unused_fd_flags(flags & O_CLOEXEC); - if (fd < 0) - return fd; - - fd_install(fd, no_free_ptr(file)); - return fd; + return FD_ADD(flags, vfs_open_tree(dfd, filename, flags)); } /* @@ -4093,8 +4078,9 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool a dec_mnt_namespaces(ucounts); return ERR_PTR(ret); } - if (!anon) - ns_tree_gen_id(&new_ns->ns); + ns_tree_gen_id(new_ns); + + new_ns->is_anon = anon; refcount_set(&new_ns->passive, 1); new_ns->mounts = RB_ROOT; init_waitqueue_head(&new_ns->poll); @@ -4283,10 +4269,10 @@ static unsigned int attr_flags_to_mnt_flags(u64 attr_flags) SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, unsigned int, attr_flags) { + struct path new_path __free(path_put) = {}; struct mnt_namespace *ns; struct fs_context *fc; - struct file *file; - struct path newmount; + struct vfsmount *new_mnt; struct mount *mnt; unsigned int mnt_flags = 0; long ret; @@ -4324,35 +4310,36 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, fc = fd_file(f)->private_data; - ret = mutex_lock_interruptible(&fc->uapi_mutex); - if (ret < 0) + ACQUIRE(mutex_intr, uapi_mutex)(&fc->uapi_mutex); + ret = ACQUIRE_ERR(mutex_intr, &uapi_mutex); + if (ret) return ret; /* There must be a valid superblock or we can't mount it */ ret = -EINVAL; if (!fc->root) - goto err_unlock; + return ret; ret = -EPERM; if (mount_too_revealing(fc->root->d_sb, &mnt_flags)) { errorfcp(fc, "VFS", "Mount too revealing"); - goto err_unlock; + return ret; } ret = -EBUSY; if (fc->phase != FS_CONTEXT_AWAITING_MOUNT) - goto err_unlock; + return ret; if (fc->sb_flags & SB_MANDLOCK) warn_mandlock(); - newmount.mnt = vfs_create_mount(fc); - if (IS_ERR(newmount.mnt)) { - ret = PTR_ERR(newmount.mnt); - goto err_unlock; - } - newmount.dentry = dget(fc->root); - newmount.mnt->mnt_flags = mnt_flags; + new_mnt = vfs_create_mount(fc); + if (IS_ERR(new_mnt)) + return PTR_ERR(new_mnt); + new_mnt->mnt_flags = mnt_flags; + + new_path.dentry = dget(fc->root); + new_path.mnt = new_mnt; /* We've done the mount bit - now move the file context into more or * less the same state as if we'd done an fspick(). We don't want to @@ -4362,38 +4349,27 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, vfs_clean_context(fc); ns = alloc_mnt_ns(current->nsproxy->mnt_ns->user_ns, true); - if (IS_ERR(ns)) { - ret = PTR_ERR(ns); - goto err_path; - } - mnt = real_mount(newmount.mnt); + if (IS_ERR(ns)) + return PTR_ERR(ns); + mnt = real_mount(new_path.mnt); ns->root = mnt; ns->nr_mounts = 1; mnt_add_to_ns(ns, mnt); - mntget(newmount.mnt); + mntget(new_path.mnt); - /* Attach to an apparent O_PATH fd with a note that we need to unmount - * it, not just simply put it. - */ - file = dentry_open(&newmount, O_PATH, fc->cred); - if (IS_ERR(file)) { - dissolve_on_fput(newmount.mnt); - ret = PTR_ERR(file); - goto err_path; + FD_PREPARE(fdf, (flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0, + dentry_open(&new_path, O_PATH, fc->cred)); + if (fdf.err) { + dissolve_on_fput(new_path.mnt); + return fdf.err; } - file->f_mode |= FMODE_NEED_UNMOUNT; - - ret = get_unused_fd_flags((flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0); - if (ret >= 0) - fd_install(ret, file); - else - fput(file); -err_path: - path_put(&newmount); -err_unlock: - mutex_unlock(&fc->uapi_mutex); - return ret; + /* + * Attach to an apparent O_PATH fd with a note that we + * need to unmount it, not just simply put it. + */ + fd_prepare_file(fdf)->f_mode |= FMODE_NEED_UNMOUNT; + return fd_publish(fdf); } static inline int vfs_move_mount(const struct path *from_path, @@ -5035,19 +5011,17 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename, unsigned, flags, struct mount_attr __user *, uattr, size_t, usize) { - struct file __free(fput) *file = NULL; - int fd; - if (!uattr && usize) return -EINVAL; - file = vfs_open_tree(dfd, filename, flags); - if (IS_ERR(file)) - return PTR_ERR(file); + FD_PREPARE(fdf, flags, vfs_open_tree(dfd, filename, flags)); + if (fdf.err) + return fdf.err; if (uattr) { - int ret; struct mount_kattr kattr = {}; + struct file *file = fd_prepare_file(fdf); + int ret; if (flags & OPEN_TREE_CLONE) kattr.kflags = MOUNT_KATTR_IDMAP_REPLACE; @@ -5063,12 +5037,7 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename, return ret; } - fd = get_unused_fd_flags(flags & O_CLOEXEC); - if (fd < 0) - return fd; - - fd_install(fd, no_free_ptr(file)); - return fd; + return fd_publish(fdf); } int show_path(struct seq_file *m, struct dentry *root) @@ -5150,6 +5119,12 @@ static u64 mnt_to_propagation_flags(struct mount *m) return propagation; } +u64 vfsmount_to_propagation_flags(struct vfsmount *mnt) +{ + return mnt_to_propagation_flags(real_mount(mnt)); +} +EXPORT_SYMBOL_GPL(vfsmount_to_propagation_flags); + static void statmount_sb_basic(struct kstatmount *s) { struct super_block *sb = s->mnt->mnt_sb; @@ -5454,11 +5429,11 @@ static int statmount_string(struct kstatmount *s, u64 flag) ret = statmount_sb_source(s, seq); break; case STATMOUNT_MNT_UIDMAP: - sm->mnt_uidmap = start; + offp = &sm->mnt_uidmap; ret = statmount_mnt_uidmap(s, seq); break; case STATMOUNT_MNT_GIDMAP: - sm->mnt_gidmap = start; + offp = &sm->mnt_gidmap; ret = statmount_mnt_gidmap(s, seq); break; default: @@ -5736,7 +5711,7 @@ static int copy_mnt_id_req(const struct mnt_id_req __user *req, ret = copy_struct_from_user(kreq, sizeof(*kreq), req, usize); if (ret) return ret; - if (kreq->spare != 0) + if (kreq->mnt_ns_fd != 0 && kreq->mnt_ns_id) return -EINVAL; /* The first valid unique mount id is MNT_UNIQUE_ID_OFFSET + 1. */ if (kreq->mnt_id <= MNT_UNIQUE_ID_OFFSET) @@ -5753,16 +5728,14 @@ static struct mnt_namespace *grab_requested_mnt_ns(const struct mnt_id_req *kreq { struct mnt_namespace *mnt_ns; - if (kreq->mnt_ns_id && kreq->spare) - return ERR_PTR(-EINVAL); - - if (kreq->mnt_ns_id) - return lookup_mnt_ns(kreq->mnt_ns_id); - - if (kreq->spare) { + if (kreq->mnt_ns_id) { + mnt_ns = lookup_mnt_ns(kreq->mnt_ns_id); + if (!mnt_ns) + return ERR_PTR(-ENOENT); + } else if (kreq->mnt_ns_fd) { struct ns_common *ns; - CLASS(fd, f)(kreq->spare); + CLASS(fd, f)(kreq->mnt_ns_fd); if (fd_empty(f)) return ERR_PTR(-EBADF); @@ -5774,11 +5747,12 @@ static struct mnt_namespace *grab_requested_mnt_ns(const struct mnt_id_req *kreq return ERR_PTR(-EINVAL); mnt_ns = to_mnt_ns(ns); + refcount_inc(&mnt_ns->passive); } else { mnt_ns = current->nsproxy->mnt_ns; + refcount_inc(&mnt_ns->passive); } - refcount_inc(&mnt_ns->passive); return mnt_ns; } @@ -5801,8 +5775,8 @@ SYSCALL_DEFINE4(statmount, const struct mnt_id_req __user *, req, return ret; ns = grab_requested_mnt_ns(&kreq); - if (!ns) - return -ENOENT; + if (IS_ERR(ns)) + return PTR_ERR(ns); if (kreq.mnt_ns_id && (ns != current->nsproxy->mnt_ns) && !ns_capable_noaudit(ns->user_ns, CAP_SYS_ADMIN)) @@ -5912,8 +5886,8 @@ static void __free_klistmount_free(const struct klistmount *kls) static inline int prepare_klistmount(struct klistmount *kls, struct mnt_id_req *kreq, size_t nr_mnt_ids) { - u64 last_mnt_id = kreq->param; + struct mnt_namespace *ns; /* The first valid unique mount id is MNT_UNIQUE_ID_OFFSET + 1. */ if (last_mnt_id != 0 && last_mnt_id <= MNT_UNIQUE_ID_OFFSET) @@ -5927,9 +5901,10 @@ static inline int prepare_klistmount(struct klistmount *kls, struct mnt_id_req * if (!kls->kmnt_ids) return -ENOMEM; - kls->ns = grab_requested_mnt_ns(kreq); - if (!kls->ns) - return -ENOENT; + ns = grab_requested_mnt_ns(kreq); + if (IS_ERR(ns)) + return PTR_ERR(ns); + kls->ns = ns; kls->mnt_parent_id = kreq->mnt_id; return 0; @@ -5985,11 +5960,8 @@ SYSCALL_DEFINE4(listmount, const struct mnt_id_req __user *, req, } struct mnt_namespace init_mnt_ns = { - .ns.inum = ns_init_inum(&init_mnt_ns), - .ns.ops = &mntns_operations, + .ns = NS_COMMON_INIT(init_mnt_ns), .user_ns = &init_user_ns, - .ns.__ns_ref = REFCOUNT_INIT(1), - .ns.ns_type = ns_common_type(&init_mnt_ns), .passive = REFCOUNT_INIT(1), .mounts = RB_ROOT, .poll = __WAIT_QUEUE_HEAD_INITIALIZER(init_mnt_ns.poll), |