1 files changed, 430 insertions, 102 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 364ceab15f0c..259c4b4f1eeb 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Copyright (C) 2006 IBM Corporation
  *
  *  Author: Serge Hallyn <serue@us.ibm.com>
  *
- *  This program is free software; you can redistribute it and/or
- *  modify it under the terms of the GNU General Public License as
- *  published by the Free Software Foundation, version 2 of the
- *  License.
- *
  *  Jun 2006 - namespaces support
  *             OpenVZ, SWsoft Inc.
  *             Pavel Emelianov <xemul@openvz.org>
@@ -22,22 +18,35 @@
 #include <linux/pid_namespace.h>
 #include <net/net_namespace.h>
 #include <linux/ipc_namespace.h>
+#include <linux/time_namespace.h>
+#include <linux/fs_struct.h>
+#include <linux/proc_fs.h>
 #include <linux/proc_ns.h>
 #include <linux/file.h>
 #include <linux/syscalls.h>
+#include <linux/cgroup.h>
+#include <linux/perf_event.h>
+#include <linux/nstree.h>
 
 static struct kmem_cache *nsproxy_cachep;
 
 struct nsproxy init_nsproxy = {
-	.count	= ATOMIC_INIT(1),
-	.uts_ns	= &init_uts_ns,
+	.count			= REFCOUNT_INIT(1),
+	.uts_ns			= &init_uts_ns,
 #if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
-	.ipc_ns	= &init_ipc_ns,
+	.ipc_ns			= &init_ipc_ns,
 #endif
-	.mnt_ns	= NULL,
-	.pid_ns	= &init_pid_ns,
+	.mnt_ns			= NULL,
+	.pid_ns_for_children	= &init_pid_ns,
 #ifdef CONFIG_NET
-	.net_ns	= &init_net,
+	.net_ns			= &init_net,
+#endif
+#ifdef CONFIG_CGROUPS
+	.cgroup_ns		= &init_cgroup_ns,
+#endif
+#ifdef CONFIG_TIME_NS
+	.time_ns		= &init_time_ns,
+	.time_ns_for_children	= &init_time_ns,
 #endif
 };
 
@@ -47,16 +56,35 @@ static inline struct nsproxy *create_nsproxy(void)
 
 	nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
 	if (nsproxy)
-		atomic_set(&nsproxy->count, 1);
+		refcount_set(&nsproxy->count, 1);
 	return nsproxy;
 }
 
+static inline void nsproxy_free(struct nsproxy *ns)
+{
+	put_mnt_ns(ns->mnt_ns);
+	put_uts_ns(ns->uts_ns);
+	put_ipc_ns(ns->ipc_ns);
+	put_pid_ns(ns->pid_ns_for_children);
+	put_time_ns(ns->time_ns);
+	put_time_ns(ns->time_ns_for_children);
+	put_cgroup_ns(ns->cgroup_ns);
+	put_net(ns->net_ns);
+	kmem_cache_free(nsproxy_cachep, ns);
+}
+
+void deactivate_nsproxy(struct nsproxy *ns)
+{
+	nsproxy_ns_active_put(ns);
+	nsproxy_free(ns);
+}
+
 /*
  * Create new nsproxy and all of its the associated namespaces.
  * Return the newly created nsproxy.  Do not attach this to the task,
  * leave it to the caller to do proper locking and attach it to task.
  */
-static struct nsproxy *create_new_namespaces(unsigned long flags,
+static struct nsproxy *create_new_namespaces(u64 flags,
 	struct task_struct *tsk, struct user_namespace *user_ns,
 	struct fs_struct *new_fs)
 {
@@ -85,32 +113,48 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_ipc;
 	}
 
-	new_nsp->pid_ns = copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns);
-	if (IS_ERR(new_nsp->pid_ns)) {
-		err = PTR_ERR(new_nsp->pid_ns);
+	new_nsp->pid_ns_for_children =
+		copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
+	if (IS_ERR(new_nsp->pid_ns_for_children)) {
+		err = PTR_ERR(new_nsp->pid_ns_for_children);
 		goto out_pid;
 	}
 
+	new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+					    tsk->nsproxy->cgroup_ns);
+	if (IS_ERR(new_nsp->cgroup_ns)) {
+		err = PTR_ERR(new_nsp->cgroup_ns);
+		goto out_cgroup;
+	}
+
 	new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
 	if (IS_ERR(new_nsp->net_ns)) {
 		err = PTR_ERR(new_nsp->net_ns);
 		goto out_net;
 	}
 
+	new_nsp->time_ns_for_children = copy_time_ns(flags, user_ns,
+					tsk->nsproxy->time_ns_for_children);
+	if (IS_ERR(new_nsp->time_ns_for_children)) {
+		err = PTR_ERR(new_nsp->time_ns_for_children);
+		goto out_time;
+	}
+	new_nsp->time_ns = get_time_ns(tsk->nsproxy->time_ns);
+
 	return new_nsp;
 
+out_time:
+	put_net(new_nsp->net_ns);
 out_net:
-	if (new_nsp->pid_ns)
-		put_pid_ns(new_nsp->pid_ns);
+	put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
+	put_pid_ns(new_nsp->pid_ns_for_children);
 out_pid:
-	if (new_nsp->ipc_ns)
-		put_ipc_ns(new_nsp->ipc_ns);
+	put_ipc_ns(new_nsp->ipc_ns);
 out_ipc:
-	if (new_nsp->uts_ns)
-		put_uts_ns(new_nsp->uts_ns);
+	put_uts_ns(new_nsp->uts_ns);
 out_uts:
-	if (new_nsp->mnt_ns)
-		put_mnt_ns(new_nsp->mnt_ns);
+	put_mnt_ns(new_nsp->mnt_ns);
 out_ns:
 	kmem_cache_free(nsproxy_cachep, new_nsp);
 	return ERR_PTR(err);
@@ -120,26 +164,22 @@ out_ns:
  * called from clone.  This now handles copy for nsproxy and all
  * namespaces therein.
  */
-int copy_namespaces(unsigned long flags, struct task_struct *tsk)
+int copy_namespaces(u64 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)
-		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 (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+			      CLONE_NEWPID | CLONE_NEWNET |
+			      CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
+		if ((flags & CLONE_VM) ||
+		    likely(old_ns->time_ns_for_children == old_ns->time_ns)) {
+			get_nsproxy(old_ns);
+			return 0;
+		}
+	} else if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
 
 	/*
 	 * CLONE_NEWIPC must detach from the undolist: after switching
@@ -148,36 +188,20 @@ 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;
-}
+	if ((flags & CLONE_VM) == 0)
+		timens_on_fork(new_ns, tsk);
 
-void free_nsproxy(struct nsproxy *ns)
-{
-	if (ns->mnt_ns)
-		put_mnt_ns(ns->mnt_ns);
-	if (ns->uts_ns)
-		put_uts_ns(ns->uts_ns);
-	if (ns->ipc_ns)
-		put_ipc_ns(ns->ipc_ns);
-	if (ns->pid_ns)
-		put_pid_ns(ns->pid_ns);
-	put_net(ns->net_ns);
-	kmem_cache_free(nsproxy_cachep, ns);
+	nsproxy_ns_active_get(new_ns);
+	tsk->nsproxy = new_ns;
+	return 0;
 }
 
 /*
@@ -191,7 +215,8 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
 	int err = 0;
 
 	if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
-			       CLONE_NEWNET | CLONE_NEWPID)))
+			       CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP |
+			       CLONE_NEWTIME)))
 		return 0;
 
 	user_ns = new_cred ? new_cred->user_ns : current_user_ns();
@@ -215,65 +240,368 @@ void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
 
 	might_sleep();
 
+	if (new)
+		nsproxy_ns_active_get(new);
+
+	task_lock(p);
 	ns = p->nsproxy;
+	p->nsproxy = new;
+	task_unlock(p);
 
-	rcu_assign_pointer(p->nsproxy, new);
-
-	if (ns && atomic_dec_and_test(&ns->count)) {
-		/*
-		 * wait for others to get what they want from this nsproxy.
-		 *
-		 * cannot release this nsproxy via the call_rcu() since
-		 * put_mnt_ns() will want to sleep
-		 */
-		synchronize_rcu();
-		free_nsproxy(ns);
-	}
+	if (ns)
+		put_nsproxy(ns);
 }
 
-void exit_task_namespaces(struct task_struct *p)
+void exit_nsproxy_namespaces(struct task_struct *p)
 {
 	switch_task_namespaces(p, NULL);
 }
 
-SYSCALL_DEFINE2(setns, int, fd, int, nstype)
+void switch_cred_namespaces(const struct cred *old, const struct cred *new)
+{
+	ns_ref_active_get(new->user_ns);
+	ns_ref_active_put(old->user_ns);
+}
+
+void get_cred_namespaces(struct task_struct *tsk)
+{
+	ns_ref_active_get(tsk->real_cred->user_ns);
+}
+
+void exit_cred_namespaces(struct task_struct *tsk)
+{
+	ns_ref_active_put(tsk->real_cred->user_ns);
+}
+
+int exec_task_namespaces(void)
 {
-	const struct proc_ns_operations *ops;
 	struct task_struct *tsk = current;
-	struct nsproxy *new_nsproxy;
-	struct proc_ns *ei;
-	struct file *file;
-	int err;
+	struct nsproxy *new;
 
-	file = proc_ns_fget(fd);
-	if (IS_ERR(file))
-		return PTR_ERR(file);
+	if (tsk->nsproxy->time_ns_for_children == tsk->nsproxy->time_ns)
+		return 0;
 
-	err = -EINVAL;
-	ei = get_proc_ns(file_inode(file));
-	ops = ei->ns_ops;
-	if (nstype && (ops->type != nstype))
-		goto out;
+	new = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
+	if (IS_ERR(new))
+		return PTR_ERR(new);
+
+	timens_on_fork(new, tsk);
+	switch_task_namespaces(tsk, new);
+	return 0;
+}
+
+static int check_setns_flags(unsigned long flags)
+{
+	if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+				 CLONE_NEWNET | CLONE_NEWTIME | CLONE_NEWUSER |
+				 CLONE_NEWPID | CLONE_NEWCGROUP)))
+		return -EINVAL;
+
+#ifndef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_PID_NS
+	if (flags & CLONE_NEWPID)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_UTS_NS
+	if (flags & CLONE_NEWUTS)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_IPC_NS
+	if (flags & CLONE_NEWIPC)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_CGROUPS
+	if (flags & CLONE_NEWCGROUP)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_NET_NS
+	if (flags & CLONE_NEWNET)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_TIME_NS
+	if (flags & CLONE_NEWTIME)
+		return -EINVAL;
+#endif
+
+	return 0;
+}
+
+static void put_nsset(struct nsset *nsset)
+{
+	unsigned flags = nsset->flags;
+
+	if (flags & CLONE_NEWUSER)
+		put_cred(nsset_cred(nsset));
+	/*
+	 * We only created a temporary copy if we attached to more than just
+	 * the mount namespace.
+	 */
+	if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
+		free_fs_struct(nsset->fs);
+	if (nsset->nsproxy)
+		nsproxy_free(nsset->nsproxy);
+}
+
+static int prepare_nsset(unsigned flags, struct nsset *nsset)
+{
+	struct task_struct *me = current;
 
-	new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
-	if (IS_ERR(new_nsproxy)) {
-		err = PTR_ERR(new_nsproxy);
+	nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs);
+	if (IS_ERR(nsset->nsproxy))
+		return PTR_ERR(nsset->nsproxy);
+
+	if (flags & CLONE_NEWUSER)
+		nsset->cred = prepare_creds();
+	else
+		nsset->cred = current_cred();
+	if (!nsset->cred)
 		goto out;
+
+	/* Only create a temporary copy of fs_struct if we really need to. */
+	if (flags == CLONE_NEWNS) {
+		nsset->fs = me->fs;
+	} else if (flags & CLONE_NEWNS) {
+		nsset->fs = copy_fs_struct(me->fs);
+		if (!nsset->fs)
+			goto out;
+	}
+
+	nsset->flags = flags;
+	return 0;
+
+out:
+	put_nsset(nsset);
+	return -ENOMEM;
+}
+
+static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
+{
+	return ns->ops->install(nsset, ns);
+}
+
+/*
+ * This is the inverse operation to unshare().
+ * Ordering is equivalent to the standard ordering used everywhere else
+ * during unshare and process creation. The switch to the new set of
+ * namespaces occurs at the point of no return after installation of
+ * all requested namespaces was successful in commit_nsset().
+ */
+static int validate_nsset(struct nsset *nsset, struct pid *pid)
+{
+	int ret = 0;
+	unsigned flags = nsset->flags;
+	struct user_namespace *user_ns = NULL;
+	struct pid_namespace *pid_ns = NULL;
+	struct nsproxy *nsp;
+	struct task_struct *tsk;
+
+	/* Take a "snapshot" of the target task's namespaces. */
+	rcu_read_lock();
+	tsk = pid_task(pid, PIDTYPE_PID);
+	if (!tsk) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+	if (!ptrace_may_access(tsk, PTRACE_MODE_READ_REALCREDS)) {
+		rcu_read_unlock();
+		return -EPERM;
+	}
+
+	task_lock(tsk);
+	nsp = tsk->nsproxy;
+	if (nsp)
+		get_nsproxy(nsp);
+	task_unlock(tsk);
+	if (!nsp) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+#ifdef CONFIG_PID_NS
+	if (flags & CLONE_NEWPID) {
+		pid_ns = task_active_pid_ns(tsk);
+		if (unlikely(!pid_ns)) {
+			rcu_read_unlock();
+			ret = -ESRCH;
+			goto out;
+		}
+		get_pid_ns(pid_ns);
+	}
+#endif
+
+#ifdef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER)
+		user_ns = get_user_ns(__task_cred(tsk)->user_ns);
+#endif
+	rcu_read_unlock();
+
+	/*
+	 * Install requested namespaces. The caller will have
+	 * verified earlier that the requested namespaces are
+	 * supported on this kernel. We don't report errors here
+	 * if a namespace is requested that isn't supported.
+	 */
+#ifdef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER) {
+		ret = validate_ns(nsset, &user_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+	if (flags & CLONE_NEWNS) {
+		ret = validate_ns(nsset, from_mnt_ns(nsp->mnt_ns));
+		if (ret)
+			goto out;
+	}
+
+#ifdef CONFIG_UTS_NS
+	if (flags & CLONE_NEWUTS) {
+		ret = validate_ns(nsset, &nsp->uts_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_IPC_NS
+	if (flags & CLONE_NEWIPC) {
+		ret = validate_ns(nsset, &nsp->ipc_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_PID_NS
+	if (flags & CLONE_NEWPID) {
+		ret = validate_ns(nsset, &pid_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_CGROUPS
+	if (flags & CLONE_NEWCGROUP) {
+		ret = validate_ns(nsset, &nsp->cgroup_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_NET_NS
+	if (flags & CLONE_NEWNET) {
+		ret = validate_ns(nsset, &nsp->net_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_TIME_NS
+	if (flags & CLONE_NEWTIME) {
+		ret = validate_ns(nsset, &nsp->time_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+out:
+	if (pid_ns)
+		put_pid_ns(pid_ns);
+	if (nsp)
+		put_nsproxy(nsp);
+	put_user_ns(user_ns);
+
+	return ret;
+}
+
+/*
+ * This is the point of no return. There are just a few namespaces
+ * that do some actual work here and it's sufficiently minimal that
+ * a separate ns_common operation seems unnecessary for now.
+ * Unshare is doing the same thing. If we'll end up needing to do
+ * more in a given namespace or a helper here is ultimately not
+ * exported anymore a simple commit handler for each namespace
+ * should be added to ns_common.
+ */
+static void commit_nsset(struct nsset *nsset)
+{
+	unsigned flags = nsset->flags;
+	struct task_struct *me = current;
+
+#ifdef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER) {
+		/* transfer ownership */
+		commit_creds(nsset_cred(nsset));
+		nsset->cred = NULL;
+	}
+#endif
+
+	/* We only need to commit if we have used a temporary fs_struct. */
+	if ((flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS)) {
+		set_fs_root(me->fs, &nsset->fs->root);
+		set_fs_pwd(me->fs, &nsset->fs->pwd);
 	}
 
-	err = ops->install(new_nsproxy, ei->ns);
-	if (err) {
-		free_nsproxy(new_nsproxy);
+#ifdef CONFIG_IPC_NS
+	if (flags & CLONE_NEWIPC)
+		exit_sem(me);
+#endif
+
+#ifdef CONFIG_TIME_NS
+	if (flags & CLONE_NEWTIME)
+		timens_commit(me, nsset->nsproxy->time_ns);
+#endif
+
+	/* transfer ownership */
+	switch_task_namespaces(me, nsset->nsproxy);
+	nsset->nsproxy = NULL;
+}
+
+SYSCALL_DEFINE2(setns, int, fd, int, flags)
+{
+	CLASS(fd, f)(fd);
+	struct ns_common *ns = NULL;
+	struct nsset nsset = {};
+	int err = 0;
+
+	if (fd_empty(f))
+		return -EBADF;
+
+	if (proc_ns_file(fd_file(f))) {
+		ns = get_proc_ns(file_inode(fd_file(f)));
+		if (flags && (ns->ns_type != flags))
+			err = -EINVAL;
+		flags = ns->ns_type;
+	} else if (!IS_ERR(pidfd_pid(fd_file(f)))) {
+		err = check_setns_flags(flags);
+	} else {
+		err = -EINVAL;
+	}
+	if (err)
+		goto out;
+
+	err = prepare_nsset(flags, &nsset);
+	if (err)
 		goto out;
+
+	if (proc_ns_file(fd_file(f)))
+		err = validate_ns(&nsset, ns);
+	else
+		err = validate_nsset(&nsset, pidfd_pid(fd_file(f)));
+	if (!err) {
+		commit_nsset(&nsset);
+		perf_event_namespaces(current);
 	}
-	switch_task_namespaces(tsk, new_nsproxy);
+	put_nsset(&nsset);
 out:
-	fput(file);
 	return err;
 }
 
 int __init nsproxy_cache_init(void)
 {
-	nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
+	nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC|SLAB_ACCOUNT);
 	return 0;
 }