Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 277 insertions, 0 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
new file mode 100644
index 000000000..f6c5d3300
--- /dev/null
+++ b/kernel/nsproxy.c
@@ -0,0 +1,277 @@
+/*
+ *  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>
+ */
+
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/nsproxy.h>
+#include <linux/init_task.h>
+#include <linux/mnt_namespace.h>
+#include <linux/utsname.h>
+#include <linux/pid_namespace.h>
+#include <net/net_namespace.h>
+#include <linux/ipc_namespace.h>
+#include <linux/proc_ns.h>
+#include <linux/file.h>
+#include <linux/syscalls.h>
+#include <linux/cgroup.h>
+#include <linux/perf_event.h>
+
+static struct kmem_cache *nsproxy_cachep;
+
+struct nsproxy init_nsproxy = {
+	.count			= ATOMIC_INIT(1),
+	.uts_ns			= &init_uts_ns,
+#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
+	.ipc_ns			= &init_ipc_ns,
+#endif
+	.mnt_ns			= NULL,
+	.pid_ns_for_children	= &init_pid_ns,
+#ifdef CONFIG_NET
+	.net_ns			= &init_net,
+#endif
+#ifdef CONFIG_CGROUPS
+	.cgroup_ns		= &init_cgroup_ns,
+#endif
+};
+
+static inline struct nsproxy *create_nsproxy(void)
+{
+	struct nsproxy *nsproxy;
+
+	nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
+	if (nsproxy)
+		atomic_set(&nsproxy->count, 1);
+	return nsproxy;
+}
+
+/*
+ * 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,
+	struct task_struct *tsk, struct user_namespace *user_ns,
+	struct fs_struct *new_fs)
+{
+	struct nsproxy *new_nsp;
+	int err;
+
+	new_nsp = create_nsproxy();
+	if (!new_nsp)
+		return ERR_PTR(-ENOMEM);
+
+	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
+	if (IS_ERR(new_nsp->mnt_ns)) {
+		err = PTR_ERR(new_nsp->mnt_ns);
+		goto out_ns;
+	}
+
+	new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
+	if (IS_ERR(new_nsp->uts_ns)) {
+		err = PTR_ERR(new_nsp->uts_ns);
+		goto out_uts;
+	}
+
+	new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
+	if (IS_ERR(new_nsp->ipc_ns)) {
+		err = PTR_ERR(new_nsp->ipc_ns);
+		goto out_ipc;
+	}
+
+	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;
+	}
+
+	return new_nsp;
+
+out_net:
+	put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
+	if (new_nsp->pid_ns_for_children)
+		put_pid_ns(new_nsp->pid_ns_for_children);
+out_pid:
+	if (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);
+out_uts:
+	if (new_nsp->mnt_ns)
+		put_mnt_ns(new_nsp->mnt_ns);
+out_ns:
+	kmem_cache_free(nsproxy_cachep, new_nsp);
+	return ERR_PTR(err);
+}
+
+/*
+ * called from clone.  This now handles copy for nsproxy and all
+ * namespaces therein.
+ */
+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;
+
+	if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+			      CLONE_NEWPID | CLONE_NEWNET |
+			      CLONE_NEWCGROUP)))) {
+		get_nsproxy(old_ns);
+		return 0;
+	}
+
+	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
+	 * namespace are unreachable.  In clone parlance, CLONE_SYSVSEM
+	 * means share undolist with parent, so we must forbid using
+	 * it along with CLONE_NEWIPC.
+	 */
+	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))
+		return  PTR_ERR(new_ns);
+
+	tsk->nsproxy = new_ns;
+	return 0;
+}
+
+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_for_children)
+		put_pid_ns(ns->pid_ns_for_children);
+	put_cgroup_ns(ns->cgroup_ns);
+	put_net(ns->net_ns);
+	kmem_cache_free(nsproxy_cachep, ns);
+}
+
+/*
+ * Called from unshare. Unshare all the namespaces part of nsproxy.
+ * On success, returns the new nsproxy.
+ */
+int unshare_nsproxy_namespaces(unsigned long unshare_flags,
+	struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
+{
+	struct user_namespace *user_ns;
+	int err = 0;
+
+	if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+			       CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
+		return 0;
+
+	user_ns = new_cred ? new_cred->user_ns : current_user_ns();
+	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	*new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
+					 new_fs ? new_fs : current->fs);
+	if (IS_ERR(*new_nsp)) {
+		err = PTR_ERR(*new_nsp);
+		goto out;
+	}
+
+out:
+	return err;
+}
+
+void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
+{
+	struct nsproxy *ns;
+
+	might_sleep();
+
+	task_lock(p);
+	ns = p->nsproxy;
+	p->nsproxy = new;
+	task_unlock(p);
+
+	if (ns && atomic_dec_and_test(&ns->count))
+		free_nsproxy(ns);
+}
+
+void exit_task_namespaces(struct task_struct *p)
+{
+	switch_task_namespaces(p, NULL);
+}
+
+SYSCALL_DEFINE2(setns, int, fd, int, nstype)
+{
+	struct task_struct *tsk = current;
+	struct nsproxy *new_nsproxy;
+	struct file *file;
+	struct ns_common *ns;
+	int err;
+
+	file = proc_ns_fget(fd);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	err = -EINVAL;
+	ns = get_proc_ns(file_inode(file));
+	if (nstype && (ns->ops->type != nstype))
+		goto out;
+
+	new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
+	if (IS_ERR(new_nsproxy)) {
+		err = PTR_ERR(new_nsproxy);
+		goto out;
+	}
+
+	err = ns->ops->install(new_nsproxy, ns);
+	if (err) {
+		free_nsproxy(new_nsproxy);
+		goto out;
+	}
+	switch_task_namespaces(tsk, new_nsproxy);
+
+	perf_event_namespaces(tsk);
+out:
+	fput(file);
+	return err;
+}
+
+int __init nsproxy_cache_init(void)
+{
+	nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
+	return 0;
+}