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-rw-r--r--kernel/nsproxy.c578
1 files changed, 578 insertions, 0 deletions
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
new file mode 100644
index 000000000..12dd41b39
--- /dev/null
+++ b/kernel/nsproxy.c
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006 IBM Corporation
+ *
+ * Author: Serge Hallyn <serue@us.ibm.com>
+ *
+ * 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/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>
+
+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
+#ifdef CONFIG_TIME_NS
+ .time_ns = &init_time_ns,
+ .time_ns_for_children = &init_time_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;
+ }
+
+ 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:
+ 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;
+ int ret;
+
+ if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
+ if (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
+ * 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);
+
+ ret = timens_on_fork(new_ns, tsk);
+ if (ret) {
+ free_nsproxy(new_ns);
+ return ret;
+ }
+
+ 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);
+ if (ns->time_ns)
+ put_time_ns(ns->time_ns);
+ if (ns->time_ns_for_children)
+ 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);
+}
+
+/*
+ * 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 |
+ CLONE_NEWTIME)))
+ 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);
+}
+
+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)
+ free_nsproxy(nsset->nsproxy);
+}
+
+static int prepare_nsset(unsigned flags, struct nsset *nsset)
+{
+ struct task_struct *me = current;
+
+ 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);
+ }
+
+#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)
+{
+ struct file *file;
+ struct ns_common *ns = NULL;
+ struct nsset nsset = {};
+ int err = 0;
+
+ file = fget(fd);
+ if (!file)
+ return -EBADF;
+
+ if (proc_ns_file(file)) {
+ ns = get_proc_ns(file_inode(file));
+ if (flags && (ns->ops->type != flags))
+ err = -EINVAL;
+ flags = ns->ops->type;
+ } else if (!IS_ERR(pidfd_pid(file))) {
+ 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(file))
+ err = validate_ns(&nsset, ns);
+ else
+ err = validate_nsset(&nsset, file->private_data);
+ if (!err) {
+ commit_nsset(&nsset);
+ perf_event_namespaces(current);
+ }
+ put_nsset(&nsset);
+out:
+ fput(file);
+ return err;
+}
+
+int __init nsproxy_cache_init(void)
+{
+ nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
+ return 0;
+}