Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull namespace changes from Eric Biederman:
 "This is an assorted mishmash of small cleanups, enhancements and bug
  fixes.

  The major theme is user namespace mount restrictions.  nsown_capable
  is killed as it encourages not thinking about details that need to be
  considered.  A very hard to hit pid namespace exiting bug was finally
  tracked and fixed.  A couple of cleanups to the basic namespace
  infrastructure.

  Finally there is an enhancement that makes per user namespace
  capabilities usable as capabilities, and an enhancement that allows
  the per userns root to nice other processes in the user namespace"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  userns:  Kill nsown_capable it makes the wrong thing easy
  capabilities: allow nice if we are privileged
  pidns: Don't have unshare(CLONE_NEWPID) imply CLONE_THREAD
  userns: Allow PR_CAPBSET_DROP in a user namespace.
  namespaces: Simplify copy_namespaces so it is clear what is going on.
  pidns: Fix hang in zap_pid_ns_processes by sending a potentially extra wakeup
  sysfs: Restrict mounting sysfs
  userns: Better restrictions on when proc and sysfs can be mounted
  vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespaces
  kernel/nsproxy.c: Improving a snippet of code.
  proc: Restrict mounting the proc filesystem
  vfs: Lock in place mounts from more privileged users

27 files changed, 177 insertions, 104 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index ad8ea9b..ef69fa5 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -831,6 +831,10 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
 	if ((flag & CL_UNPRIVILEGED) && (mnt->mnt.mnt_flags & MNT_READONLY))
 		mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
 
+	/* Don't allow unprivileged users to reveal what is under a mount */
+	if ((flag & CL_UNPRIVILEGED) && list_empty(&old->mnt_expire))
+		mnt->mnt.mnt_flags |= MNT_LOCKED;
+
 	atomic_inc(&sb->s_active);
 	mnt->mnt.mnt_sb = sb;
 	mnt->mnt.mnt_root = dget(root);
@@ -1327,6 +1331,8 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
 		goto dput_and_out;
 	if (!check_mnt(mnt))
 		goto dput_and_out;
+	if (mnt->mnt.mnt_flags & MNT_LOCKED)
+		goto dput_and_out;
 
 	retval = do_umount(mnt, flags);
 dput_and_out:
@@ -1349,14 +1355,11 @@ SYSCALL_DEFINE1(oldumount, char __user *, name)
 
 #endif
 
-static bool mnt_ns_loop(struct path *path)
+static bool is_mnt_ns_file(struct dentry *dentry)
 {
-	/* Could bind mounting the mount namespace inode cause a
-	 * mount namespace loop?
-	 */
-	struct inode *inode = path->dentry->d_inode;
+	/* Is this a proxy for a mount namespace? */
+	struct inode *inode = dentry->d_inode;
 	struct proc_ns *ei;
-	struct mnt_namespace *mnt_ns;
 
 	if (!proc_ns_inode(inode))
 		return false;
@@ -1365,7 +1368,19 @@ static bool mnt_ns_loop(struct path *path)
 	if (ei->ns_ops != &mntns_operations)
 		return false;
 
-	mnt_ns = ei->ns;
+	return true;
+}
+
+static bool mnt_ns_loop(struct dentry *dentry)
+{
+	/* Could bind mounting the mount namespace inode cause a
+	 * mount namespace loop?
+	 */
+	struct mnt_namespace *mnt_ns;
+	if (!is_mnt_ns_file(dentry))
+		return false;
+
+	mnt_ns = get_proc_ns(dentry->d_inode)->ns;
 	return current->nsproxy->mnt_ns->seq >= mnt_ns->seq;
 }
 
@@ -1374,13 +1389,17 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
 {
 	struct mount *res, *p, *q, *r, *parent;
 
-	if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
+	if (!(flag & CL_COPY_UNBINDABLE) && IS_MNT_UNBINDABLE(mnt))
+		return ERR_PTR(-EINVAL);
+
+	if (!(flag & CL_COPY_MNT_NS_FILE) && is_mnt_ns_file(dentry))
 		return ERR_PTR(-EINVAL);
 
 	res = q = clone_mnt(mnt, dentry, flag);
 	if (IS_ERR(q))
 		return q;
 
+	q->mnt.mnt_flags &= ~MNT_LOCKED;
 	q->mnt_mountpoint = mnt->mnt_mountpoint;
 
 	p = mnt;
@@ -1390,7 +1409,13 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
 			continue;
 
 		for (s = r; s; s = next_mnt(s, r)) {
-			if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(s)) {
+			if (!(flag & CL_COPY_UNBINDABLE) &&
+			    IS_MNT_UNBINDABLE(s)) {
+				s = skip_mnt_tree(s);
+				continue;
+			}
+			if (!(flag & CL_COPY_MNT_NS_FILE) &&
+			    is_mnt_ns_file(s->mnt.mnt_root)) {
 				s = skip_mnt_tree(s);
 				continue;
 			}
@@ -1696,6 +1721,19 @@ static int do_change_type(struct path *path, int flag)
 	return err;
 }
 
+static bool has_locked_children(struct mount *mnt, struct dentry *dentry)
+{
+	struct mount *child;
+	list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
+		if (!is_subdir(child->mnt_mountpoint, dentry))
+			continue;
+
+		if (child->mnt.mnt_flags & MNT_LOCKED)
+			return true;
+	}
+	return false;
+}
+
 /*
  * do loopback mount.
  */
@@ -1713,7 +1751,7 @@ static int do_loopback(struct path *path, const char *old_name,
 		return err;
 
 	err = -EINVAL;
-	if (mnt_ns_loop(&old_path))
+	if (mnt_ns_loop(old_path.dentry))
 		goto out; 
 
 	mp = lock_mount(path);
@@ -1731,8 +1769,11 @@ static int do_loopback(struct path *path, const char *old_name,
 	if (!check_mnt(parent) || !check_mnt(old))
 		goto out2;
 
+	if (!recurse && has_locked_children(old, old_path.dentry))
+		goto out2;
+
 	if (recurse)
-		mnt = copy_tree(old, old_path.dentry, 0);
+		mnt = copy_tree(old, old_path.dentry, CL_COPY_MNT_NS_FILE);
 	else
 		mnt = clone_mnt(old, old_path.dentry, 0);
 
@@ -1741,6 +1782,8 @@ static int do_loopback(struct path *path, const char *old_name,
 		goto out2;
 	}
 
+	mnt->mnt.mnt_flags &= ~MNT_LOCKED;
+
 	err = graft_tree(mnt, parent, mp);
 	if (err) {
 		br_write_lock(&vfsmount_lock);
@@ -1853,6 +1896,9 @@ static int do_move_mount(struct path *path, const char *old_name)
 	if (!check_mnt(p) || !check_mnt(old))
 		goto out1;
 
+	if (old->mnt.mnt_flags & MNT_LOCKED)
+		goto out1;
+
 	err = -EINVAL;
 	if (old_path.dentry != old_path.mnt->mnt_root)
 		goto out1;
@@ -2389,7 +2435,7 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
 
 	namespace_lock();
 	/* First pass: copy the tree topology */
-	copy_flags = CL_COPY_ALL | CL_EXPIRE;
+	copy_flags = CL_COPY_UNBINDABLE | CL_EXPIRE;
 	if (user_ns != mnt_ns->user_ns)
 		copy_flags |= CL_SHARED_TO_SLAVE | CL_UNPRIVILEGED;
 	new = copy_tree(old, old->mnt.mnt_root, copy_flags);
@@ -2424,6 +2470,10 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
 		}
 		p = next_mnt(p, old);
 		q = next_mnt(q, new);
+		if (!q)
+			break;
+		while (p->mnt.mnt_root != q->mnt.mnt_root)
+			p = next_mnt(p, old);
 	}
 	namespace_unlock();
 
@@ -2630,6 +2680,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
 		goto out4;
 	if (!check_mnt(root_mnt) || !check_mnt(new_mnt))
 		goto out4;
+	if (new_mnt->mnt.mnt_flags & MNT_LOCKED)
+		goto out4;
 	error = -ENOENT;
 	if (d_unlinked(new.dentry))
 		goto out4;
@@ -2653,6 +2705,10 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
 	br_write_lock(&vfsmount_lock);
 	detach_mnt(new_mnt, &parent_path);
 	detach_mnt(root_mnt, &root_parent);
+	if (root_mnt->mnt.mnt_flags & MNT_LOCKED) {
+		new_mnt->mnt.mnt_flags |= MNT_LOCKED;
+		root_mnt->mnt.mnt_flags &= ~MNT_LOCKED;
+	}
 	/* mount old root on put_old */
 	attach_mnt(root_mnt, old_mnt, old_mp);
 	/* mount new_root on / */
@@ -2811,25 +2867,38 @@ bool current_chrooted(void)
 	return chrooted;
 }
 
-void update_mnt_policy(struct user_namespace *userns)
+bool fs_fully_visible(struct file_system_type *type)
 {
 	struct mnt_namespace *ns = current->nsproxy->mnt_ns;
 	struct mount *mnt;
+	bool visible = false;
 
-	down_read(&namespace_sem);
+	if (unlikely(!ns))
+		return false;
+
+	namespace_lock();
 	list_for_each_entry(mnt, &ns->list, mnt_list) {
-		switch (mnt->mnt.mnt_sb->s_magic) {
-		case SYSFS_MAGIC:
-			userns->may_mount_sysfs = true;
-			break;
-		case PROC_SUPER_MAGIC:
-			userns->may_mount_proc = true;
-			break;
+		struct mount *child;
+		if (mnt->mnt.mnt_sb->s_type != type)
+			continue;
+
+		/* This mount is not fully visible if there are any child mounts
+		 * that cover anything except for empty directories.
+		 */
+		list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
+			struct inode *inode = child->mnt_mountpoint->d_inode;
+			if (!S_ISDIR(inode->i_mode))
+				goto next;
+			if (inode->i_nlink != 2)
+				goto next;
 		}
-		if (userns->may_mount_sysfs && userns->may_mount_proc)
-			break;
+		visible = true;
+		goto found;
+	next:	;
 	}
-	up_read(&namespace_sem);
+found:
+	namespace_unlock();
+	return visible;
 }
 
 static void *mntns_get(struct task_struct *task)
@@ -2860,8 +2929,8 @@ static int mntns_install(struct nsproxy *nsproxy, void *ns)
 	struct path root;
 
 	if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
-	    !nsown_capable(CAP_SYS_CHROOT) ||
-	    !nsown_capable(CAP_SYS_ADMIN))
+	    !ns_capable(current_user_ns(), CAP_SYS_CHROOT) ||
+	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
 		return -EPERM;
 
 	if (fs->users != 1)
diff --git a/fs/open.c b/fs/open.c
index 8070825..2a731b0 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -443,7 +443,7 @@ retry:
 		goto dput_and_out;
 
 	error = -EPERM;
-	if (!nsown_capable(CAP_SYS_CHROOT))
+	if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
 		goto dput_and_out;
 	error = security_path_chroot(&path);
 	if (error)
diff --git a/fs/pnode.h b/fs/pnode.h
index b091445..59e7eda 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -19,11 +19,14 @@
 
 #define CL_EXPIRE    		0x01
 #define CL_SLAVE     		0x02
-#define CL_COPY_ALL 		0x04
+#define CL_COPY_UNBINDABLE	0x04
 #define CL_MAKE_SHARED 		0x08
 #define CL_PRIVATE 		0x10
 #define CL_SHARED_TO_SLAVE	0x20
 #define CL_UNPRIVILEGED		0x40
+#define CL_COPY_MNT_NS_FILE	0x80
+
+#define CL_COPY_ALL		(CL_COPY_UNBINDABLE | CL_COPY_MNT_NS_FILE)
 
 static inline void set_mnt_shared(struct mount *mnt)
 {
diff --git a/fs/proc/root.c b/fs/proc/root.c
index e0a790d..87dbcbe 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -110,7 +110,11 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
 		ns = task_active_pid_ns(current);
 		options = data;
 
-		if (!current_user_ns()->may_mount_proc)
+		if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
+			return ERR_PTR(-EPERM);
+
+		/* Does the mounter have privilege over the pid namespace? */
+		if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
 			return ERR_PTR(-EPERM);
 	}
 
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index fd7ce7a..834ec2c 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -112,8 +112,15 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
 	struct super_block *sb;
 	int error;
 
-	if (!(flags & MS_KERNMOUNT) && !current_user_ns()->may_mount_sysfs)
-		return ERR_PTR(-EPERM);
+	if (!(flags & MS_KERNMOUNT)) {
+		if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
+			return ERR_PTR(-EPERM);
+
+		for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) {
+			if (!kobj_ns_current_may_mount(type))
+				return ERR_PTR(-EPERM);
+		}
+	}
 
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
diff --git a/include/linux/capability.h b/include/linux/capability.h
index d9a4f7f..a6ee1f9 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -210,7 +210,6 @@ extern bool has_ns_capability_noaudit(struct task_struct *t,
 				      struct user_namespace *ns, int cap);
 extern bool capable(int cap);
 extern bool ns_capable(struct user_namespace *ns, int cap);
-extern bool nsown_capable(int cap);
 extern bool inode_capable(const struct inode *inode, int cap);
 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3b4cd82..529d871 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1900,6 +1900,7 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
 extern int freeze_super(struct super_block *super);
 extern int thaw_super(struct super_block *super);
 extern bool our_mnt(struct vfsmount *mnt);
+extern bool fs_fully_visible(struct file_system_type *);
 
 extern int current_umask(void);
 
diff --git a/include/linux/kobject_ns.h b/include/linux/kobject_ns.h
index f66b065..df32d25 100644
--- a/include/linux/kobject_ns.h
+++ b/include/linux/kobject_ns.h
@@ -39,6 +39,7 @@ enum kobj_ns_type {
  */
 struct kobj_ns_type_operations {
 	enum kobj_ns_type type;
+	bool (*current_may_mount)(void);
 	void *(*grab_current_ns)(void);
 	const void *(*netlink_ns)(struct sock *sk);
 	const void *(*initial_ns)(void);
@@ -50,6 +51,7 @@ int kobj_ns_type_registered(enum kobj_ns_type type);
 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent);
 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj);
 
+bool kobj_ns_current_may_mount(enum kobj_ns_type type);
 void *kobj_ns_grab_current(enum kobj_ns_type type);
 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
 const void *kobj_ns_initial(enum kobj_ns_type type);
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 73005f9..38cd98f 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -48,6 +48,7 @@ struct mnt_namespace;
 #define MNT_INTERNAL	0x4000
 
 #define MNT_LOCK_READONLY	0x400000
+#define MNT_LOCKED		0x800000
 
 struct vfsmount {
 	struct dentry *mnt_root;	/* root of the mounted tree */
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 14105c2..4db2985 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -27,8 +27,6 @@ struct user_namespace {
 	kuid_t			owner;
 	kgid_t			group;
 	unsigned int		proc_inum;
-	bool			may_mount_sysfs;
-	bool			may_mount_proc;
 };
 
 extern struct user_namespace init_user_ns;
@@ -85,6 +83,4 @@ static inline void put_user_ns(struct user_namespace *ns)
 
 #endif
 
-void update_mnt_policy(struct user_namespace *userns);
-
 #endif /* _LINUX_USER_H */
diff --git a/ipc/namespace.c b/ipc/namespace.c
index 7ee61bf..4be6581 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -171,7 +171,7 @@ static int ipcns_install(struct nsproxy *nsproxy, void *new)
 {
 	struct ipc_namespace *ns = new;
 	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
-	    !nsown_capable(CAP_SYS_ADMIN))
+	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
 		return -EPERM;
 
 	/* Ditch state from the old ipc namespace */
diff --git a/kernel/capability.c b/kernel/capability.c
index f6c2ce5..6fc1c8a 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -433,18 +433,6 @@ bool capable(int cap)
 EXPORT_SYMBOL(capable);
 
 /**
- * nsown_capable - Check superior capability to one's own user_ns
- * @cap: The capability in question
- *
- * Return true if the current task has the given superior capability
- * targeted at its own user namespace.
- */
-bool nsown_capable(int cap)
-{
-	return ns_capable(current_user_ns(), cap);
-}
-
-/**
  * inode_capable - Check superior capability over inode
  * @inode: The inode in question
  * @cap: The capability in question
diff --git a/kernel/fork.c b/kernel/fork.c
index bf46287..c9eaf201 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1825,11 +1825,6 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
 	if (unshare_flags & CLONE_NEWUSER)
 		unshare_flags |= CLONE_THREAD | CLONE_FS;
 	/*
-	 * If unsharing a pid namespace must also unshare the thread.
-	 */
-	if (unshare_flags & CLONE_NEWPID)
-		unshare_flags |= CLONE_THREAD;
-	/*
 	 * If unsharing a thread from a thread group, must also unshare vm.
 	 */
 	if (unshare_flags & CLONE_THREAD)
diff --git a/kernel/groups.c b/kernel/groups.c
index 6b2588d..90cf1c3 100644
--- a/kernel/groups.c
+++ b/kernel/groups.c
@@ -233,7 +233,7 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
 	struct group_info *group_info;
 	int retval;
 
-	if (!nsown_capable(CAP_SETGID))
+	if (!ns_capable(current_user_ns(), CAP_SETGID))
 		return -EPERM;
 	if ((unsigned)gidsetsize > NGROUPS_MAX)
 		return -EINVAL;
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 997cbb9..8e78110 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -126,22 +126,16 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
 	struct nsproxy *old_ns = tsk->nsproxy;
 	struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
 	struct nsproxy *new_ns;
-	int err = 0;
 
-	if (!old_ns)
+	if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+			      CLONE_NEWPID | CLONE_NEWNET)))) {
+		get_nsproxy(old_ns);
 		return 0;
-
-	get_nsproxy(old_ns);
-
-	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
-				CLONE_NEWPID | CLONE_NEWNET)))
-		return 0;
-
-	if (!ns_capable(user_ns, CAP_SYS_ADMIN)) {
-		err = -EPERM;
-		goto out;
 	}
 
+	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
 	/*
 	 * CLONE_NEWIPC must detach from the undolist: after switching
 	 * to a new ipc namespace, the semaphore arrays from the old
@@ -149,22 +143,16 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
 	 * means share undolist with parent, so we must forbid using
 	 * it along with CLONE_NEWIPC.
 	 */
-	if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) {
-		err = -EINVAL;
-		goto out;
-	}
+	if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
+		(CLONE_NEWIPC | CLONE_SYSVSEM)) 
+		return -EINVAL;
 
 	new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
-	if (IS_ERR(new_ns)) {
-		err = PTR_ERR(new_ns);
-		goto out;
-	}
+	if (IS_ERR(new_ns))
+		return  PTR_ERR(new_ns);
 
 	tsk->nsproxy = new_ns;
-
-out:
-	put_nsproxy(old_ns);
-	return err;
+	return 0;
 }
 
 void free_nsproxy(struct nsproxy *ns)
diff --git a/kernel/pid.c b/kernel/pid.c
index 66505c1..ebe5e80 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -265,6 +265,7 @@ void free_pid(struct pid *pid)
 		struct pid_namespace *ns = upid->ns;
 		hlist_del_rcu(&upid->pid_chain);
 		switch(--ns->nr_hashed) {
+		case 2:
 		case 1:
 			/* When all that is left in the pid namespace
 			 * is the reaper wake up the reaper.  The reaper
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 601bb36..4208655 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -329,7 +329,7 @@ static int pidns_install(struct nsproxy *nsproxy, void *ns)
 	struct pid_namespace *ancestor, *new = ns;
 
 	if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
-	    !nsown_capable(CAP_SYS_ADMIN))
+	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
 		return -EPERM;
 
 	/*
diff --git a/kernel/sys.c b/kernel/sys.c
index 771129b..c18ecca 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -337,7 +337,7 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 	if (rgid != (gid_t) -1) {
 		if (gid_eq(old->gid, krgid) ||
 		    gid_eq(old->egid, krgid) ||
-		    nsown_capable(CAP_SETGID))
+		    ns_capable(old->user_ns, CAP_SETGID))
 			new->gid = krgid;
 		else
 			goto error;
@@ -346,7 +346,7 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 		if (gid_eq(old->gid, kegid) ||
 		    gid_eq(old->egid, kegid) ||
 		    gid_eq(old->sgid, kegid) ||
-		    nsown_capable(CAP_SETGID))
+		    ns_capable(old->user_ns, CAP_SETGID))
 			new->egid = kegid;
 		else
 			goto error;
@@ -387,7 +387,7 @@ SYSCALL_DEFINE1(setgid, gid_t, gid)
 	old = current_cred();
 
 	retval = -EPERM;
-	if (nsown_capable(CAP_SETGID))
+	if (ns_capable(old->user_ns, CAP_SETGID))
 		new->gid = new->egid = new->sgid = new->fsgid = kgid;
 	else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
 		new->egid = new->fsgid = kgid;
@@ -471,7 +471,7 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 		new->uid = kruid;
 		if (!uid_eq(old->uid, kruid) &&
 		    !uid_eq(old->euid, kruid) &&
-		    !nsown_capable(CAP_SETUID))
+		    !ns_capable(old->user_ns, CAP_SETUID))
 			goto error;
 	}
 
@@ -480,7 +480,7 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 		if (!uid_eq(old->uid, keuid) &&
 		    !uid_eq(old->euid, keuid) &&
 		    !uid_eq(old->suid, keuid) &&
-		    !nsown_capable(CAP_SETUID))
+		    !ns_capable(old->user_ns, CAP_SETUID))
 			goto error;
 	}
 
@@ -534,7 +534,7 @@ SYSCALL_DEFINE1(setuid, uid_t, uid)
 	old = current_cred();
 
 	retval = -EPERM;
-	if (nsown_capable(CAP_SETUID)) {
+	if (ns_capable(old->user_ns, CAP_SETUID)) {
 		new->suid = new->uid = kuid;
 		if (!uid_eq(kuid, old->uid)) {
 			retval = set_user(new);
@@ -591,7 +591,7 @@ SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 	old = current_cred();
 
 	retval = -EPERM;
-	if (!nsown_capable(CAP_SETUID)) {
+	if (!ns_capable(old->user_ns, CAP_SETUID)) {
 		if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
 		    !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
 			goto error;
@@ -673,7 +673,7 @@ SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 	old = current_cred();
 
 	retval = -EPERM;
-	if (!nsown_capable(CAP_SETGID)) {
+	if (!ns_capable(old->user_ns, CAP_SETGID)) {
 		if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
 		    !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
 			goto error;
@@ -744,7 +744,7 @@ SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 
 	if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
 	    uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
-	    nsown_capable(CAP_SETUID)) {
+	    ns_capable(old->user_ns, CAP_SETUID)) {
 		if (!uid_eq(kuid, old->fsuid)) {
 			new->fsuid = kuid;
 			if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
@@ -783,7 +783,7 @@ SYSCALL_DEFINE1(setfsgid, gid_t, gid)
 
 	if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
 	    gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
-	    nsown_capable(CAP_SETGID)) {
+	    ns_capable(old->user_ns, CAP_SETGID)) {
 		if (!gid_eq(kgid, old->fsgid)) {
 			new->fsgid = kgid;
 			goto change_okay;
diff --git a/kernel/uid16.c b/kernel/uid16.c
index f6c83d7..602e5bb 100644
--- a/kernel/uid16.c
+++ b/kernel/uid16.c
@@ -176,7 +176,7 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
 	struct group_info *group_info;
 	int retval;
 
-	if (!nsown_capable(CAP_SETGID))
+	if (!ns_capable(current_user_ns(), CAP_SETGID))
 		return -EPERM;
 	if ((unsigned)gidsetsize > NGROUPS_MAX)
 		return -EINVAL;
diff --git a/kernel/user.c b/kernel/user.c
index 69b4c3d..5bbb919 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -51,8 +51,6 @@ struct user_namespace init_user_ns = {
 	.owner = GLOBAL_ROOT_UID,
 	.group = GLOBAL_ROOT_GID,
 	.proc_inum = PROC_USER_INIT_INO,
-	.may_mount_sysfs = true,
-	.may_mount_proc = true,
 };
 EXPORT_SYMBOL_GPL(init_user_ns);
 
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 9064b91..13fb113 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -101,8 +101,6 @@ int create_user_ns(struct cred *new)
 
 	set_cred_user_ns(new, ns);
 
-	update_mnt_policy(ns);
-
 	return 0;
 }
 
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 2fc8576..fd39312 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -114,7 +114,7 @@ static int utsns_install(struct nsproxy *nsproxy, void *new)
 	struct uts_namespace *ns = new;
 
 	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
-	    !nsown_capable(CAP_SYS_ADMIN))
+	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
 		return -EPERM;
 
 	get_uts_ns(ns);
diff --git a/lib/kobject.c b/lib/kobject.c
index 1d46c15..9621751 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -931,6 +931,21 @@ const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
 	return kobj_child_ns_ops(kobj->parent);
 }
 
+bool kobj_ns_current_may_mount(enum kobj_ns_type type)
+{
+	bool may_mount = false;
+
+	if (type == KOBJ_NS_TYPE_NONE)
+		return true;
+
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+	    kobj_ns_ops_tbl[type])
+		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
+	spin_unlock(&kobj_ns_type_lock);
+
+	return may_mount;
+}
 
 void *kobj_ns_grab_current(enum kobj_ns_type type)
 {
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 3f40ea9..d954b56 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1196,6 +1196,13 @@ static void remove_queue_kobjects(struct net_device *net)
 #endif
 }
 
+static bool net_current_may_mount(void)
+{
+	struct net *net = current->nsproxy->net_ns;
+
+	return ns_capable(net->user_ns, CAP_SYS_ADMIN);
+}
+
 static void *net_grab_current_ns(void)
 {
 	struct net *ns = current->nsproxy->net_ns;
@@ -1218,6 +1225,7 @@ static const void *net_netlink_ns(struct sock *sk)
 
 struct kobj_ns_type_operations net_ns_type_operations = {
 	.type = KOBJ_NS_TYPE_NET,
+	.current_may_mount = net_current_may_mount,
 	.grab_current_ns = net_grab_current_ns,
 	.netlink_ns = net_netlink_ns,
 	.initial_ns = net_initial_ns,
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index f9765203..81d3a9a 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -651,7 +651,7 @@ static int netns_install(struct nsproxy *nsproxy, void *ns)
 	struct net *net = ns;
 
 	if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
-	    !nsown_capable(CAP_SYS_ADMIN))
+	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
 		return -EPERM;
 
 	put_net(nsproxy->net_ns);
diff --git a/net/core/scm.c b/net/core/scm.c
index b4da80b..b442e7e 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -56,9 +56,9 @@ static __inline__ int scm_check_creds(struct ucred *creds)
 	if ((creds->pid == task_tgid_vnr(current) ||
 	     ns_capable(task_active_pid_ns(current)->user_ns, CAP_SYS_ADMIN)) &&
 	    ((uid_eq(uid, cred->uid)   || uid_eq(uid, cred->euid) ||
-	      uid_eq(uid, cred->suid)) || nsown_capable(CAP_SETUID)) &&
+	      uid_eq(uid, cred->suid)) || ns_capable(cred->user_ns, CAP_SETUID)) &&
 	    ((gid_eq(gid, cred->gid)   || gid_eq(gid, cred->egid) ||
-	      gid_eq(gid, cred->sgid)) || nsown_capable(CAP_SETGID))) {
+	      gid_eq(gid, cred->sgid)) || ns_capable(cred->user_ns, CAP_SETGID))) {
 	       return 0;
 	}
 	return -EPERM;
diff --git a/security/commoncap.c b/security/commoncap.c
index c44b6fe..b9d613e 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -768,16 +768,16 @@ int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
  */
 static int cap_safe_nice(struct task_struct *p)
 {
-	int is_subset;
+	int is_subset, ret = 0;
 
 	rcu_read_lock();
 	is_subset = cap_issubset(__task_cred(p)->cap_permitted,
 				 current_cred()->cap_permitted);
+	if (!is_subset && !ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE))
+		ret = -EPERM;
 	rcu_read_unlock();
 
-	if (!is_subset && !capable(CAP_SYS_NICE))
-		return -EPERM;
-	return 0;
+	return ret;
 }
 
 /**
@@ -824,7 +824,7 @@ int cap_task_setnice(struct task_struct *p, int nice)
  */
 static long cap_prctl_drop(struct cred *new, unsigned long cap)
 {
-	if (!capable(CAP_SETPCAP))
+	if (!ns_capable(current_user_ns(), CAP_SETPCAP))
 		return -EPERM;
 	if (!cap_valid(cap))
 		return -EINVAL;