* incremented count after it has set MNT_WRITE_HOLD.
*/
smp_mb();
- while (mnt->mnt.mnt_flags & MNT_WRITE_HOLD)
+ while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD)
cpu_relax();
/*
* After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
if (!mnt)
return ERR_PTR(-ENOMEM);
- if (flag & (CL_SLAVE | CL_PRIVATE))
+ if (flag & (CL_SLAVE | CL_PRIVATE | CL_SHARED_TO_SLAVE))
mnt->mnt_group_id = 0; /* not a peer of original */
else
mnt->mnt_group_id = old->mnt_group_id;
list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
br_write_unlock(&vfsmount_lock);
- if (flag & CL_SLAVE) {
+ if ((flag & CL_SLAVE) ||
+ ((flag & CL_SHARED_TO_SLAVE) && IS_MNT_SHARED(old))) {
list_add(&mnt->mnt_slave, &old->mnt_slave_list);
mnt->mnt_master = old;
CLEAR_MNT_SHARED(mnt);
goto dput_and_out;
retval = -EPERM;
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(mnt->mnt_ns->user_ns, CAP_SYS_ADMIN))
goto dput_and_out;
retval = do_umount(mnt, flags);
static int mount_is_safe(struct path *path)
{
- if (capable(CAP_SYS_ADMIN))
+ if (ns_capable(real_mount(path->mnt)->mnt_ns->user_ns, CAP_SYS_ADMIN))
return 0;
return -EPERM;
#ifdef notyet
int type;
int err = 0;
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(mnt->mnt_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (path->dentry != path->mnt->mnt_root)
struct mount *p;
struct mount *old;
int err = 0;
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(real_mount(path->mnt)->mnt_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (!old_name || !*old_name)
return -EINVAL;
return ERR_PTR(err);
}
-static struct vfsmount *
-do_kern_mount(const char *fstype, int flags, const char *name, void *data)
-{
- struct file_system_type *type = get_fs_type(fstype);
- struct vfsmount *mnt;
- if (!type)
- return ERR_PTR(-ENODEV);
- mnt = vfs_kern_mount(type, flags, name, data);
- if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
- !mnt->mnt_sb->s_subtype)
- mnt = fs_set_subtype(mnt, fstype);
- put_filesystem(type);
- return mnt;
-}
-
/*
* add a mount into a namespace's mount tree
*/
* create a new mount for userspace and request it to be added into the
* namespace's tree
*/
-static int do_new_mount(struct path *path, const char *type, int flags,
+static int do_new_mount(struct path *path, const char *fstype, int flags,
int mnt_flags, const char *name, void *data)
{
+ struct file_system_type *type;
+ struct user_namespace *user_ns;
struct vfsmount *mnt;
int err;
- if (!type)
+ if (!fstype)
return -EINVAL;
/* we need capabilities... */
- if (!capable(CAP_SYS_ADMIN))
+ user_ns = real_mount(path->mnt)->mnt_ns->user_ns;
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
- mnt = do_kern_mount(type, flags, name, data);
+ type = get_fs_type(fstype);
+ if (!type)
+ return -ENODEV;
+
+ if (user_ns != &init_user_ns) {
+ if (!(type->fs_flags & FS_USERNS_MOUNT)) {
+ put_filesystem(type);
+ return -EPERM;
+ }
+ /* Only in special cases allow devices from mounts
+ * created outside the initial user namespace.
+ */
+ if (!(type->fs_flags & FS_USERNS_DEV_MOUNT)) {
+ flags |= MS_NODEV;
+ mnt_flags |= MNT_NODEV;
+ }
+ }
+
+ mnt = vfs_kern_mount(type, flags, name, data);
+ if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
+ !mnt->mnt_sb->s_subtype)
+ mnt = fs_set_subtype(mnt, fstype);
+
+ put_filesystem(type);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
static void free_mnt_ns(struct mnt_namespace *ns)
{
+ proc_free_inum(ns->proc_inum);
put_user_ns(ns->user_ns);
kfree(ns);
}
static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns)
{
struct mnt_namespace *new_ns;
+ int ret;
new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
if (!new_ns)
return ERR_PTR(-ENOMEM);
+ ret = proc_alloc_inum(&new_ns->proc_inum);
+ if (ret) {
+ kfree(new_ns);
+ return ERR_PTR(ret);
+ }
new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
atomic_set(&new_ns->count, 1);
new_ns->root = NULL;
struct mount *p, *q;
struct mount *old = mnt_ns->root;
struct mount *new;
+ int copy_flags;
new_ns = alloc_mnt_ns(user_ns);
if (IS_ERR(new_ns))
down_write(&namespace_sem);
/* First pass: copy the tree topology */
- new = copy_tree(old, old->mnt.mnt_root, CL_COPY_ALL | CL_EXPIRE);
+ copy_flags = CL_COPY_ALL | CL_EXPIRE;
+ if (user_ns != mnt_ns->user_ns)
+ copy_flags |= CL_SHARED_TO_SLAVE;
+ new = copy_tree(old, old->mnt.mnt_root, copy_flags);
if (IS_ERR(new)) {
up_write(&namespace_sem);
free_mnt_ns(new_ns);
struct mount *new_mnt, *root_mnt;
int error;
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
error = user_path_dir(new_root, &new);
struct vfsmount *mnt;
struct mnt_namespace *ns;
struct path root;
+ struct file_system_type *type;
- mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
+ type = get_fs_type("rootfs");
+ if (!type)
+ panic("Can't find rootfs type");
+ mnt = vfs_kern_mount(type, 0, "rootfs", NULL);
+ put_filesystem(type);
if (IS_ERR(mnt))
panic("Can't create rootfs");
struct mnt_namespace *mnt_ns = ns;
struct path root;
- if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_CHROOT))
- return -EINVAL;
+ if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
+ !nsown_capable(CAP_SYS_CHROOT) ||
+ !nsown_capable(CAP_SYS_ADMIN))
+ return -EPERM;
if (fs->users != 1)
return -EINVAL;
return 0;
}
+static unsigned int mntns_inum(void *ns)
+{
+ struct mnt_namespace *mnt_ns = ns;
+ return mnt_ns->proc_inum;
+}
+
const struct proc_ns_operations mntns_operations = {
.name = "mnt",
.type = CLONE_NEWNS,
.get = mntns_get,
.put = mntns_put,
.install = mntns_install,
+ .inum = mntns_inum,
};