#include <linux/pid.h>
#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
#include <linux/syscalls.h>
#include <linux/err.h>
#include <linux/acct.h>
return NULL;
}
+static void proc_cleanup_work(struct work_struct *work)
+{
+ struct pid_namespace *ns = container_of(work, struct pid_namespace, proc_work);
+ pid_ns_release_proc(ns);
+}
+
/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
#define MAX_PID_NS_LEVEL 32
-static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns)
+static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns,
+ struct pid_namespace *parent_pid_ns)
{
struct pid_namespace *ns;
unsigned int level = parent_pid_ns->level + 1;
if (ns->pid_cachep == NULL)
goto out_free_map;
+ err = proc_alloc_inum(&ns->proc_inum);
+ if (err)
+ goto out_free_map;
+
kref_init(&ns->kref);
ns->level = level;
ns->parent = get_pid_ns(parent_pid_ns);
+ ns->user_ns = get_user_ns(user_ns);
+ ns->nr_hashed = PIDNS_HASH_ADDING;
+ INIT_WORK(&ns->proc_work, proc_cleanup_work);
set_bit(0, ns->pidmap[0].page);
atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
for (i = 1; i < PIDMAP_ENTRIES; i++)
atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
- err = pid_ns_prepare_proc(ns);
- if (err)
- goto out_put_parent_pid_ns;
-
return ns;
-out_put_parent_pid_ns:
- put_pid_ns(parent_pid_ns);
out_free_map:
kfree(ns->pidmap[0].page);
out_free:
{
int i;
+ proc_free_inum(ns->proc_inum);
for (i = 0; i < PIDMAP_ENTRIES; i++)
kfree(ns->pidmap[i].page);
+ put_user_ns(ns->user_ns);
kmem_cache_free(pid_ns_cachep, ns);
}
-struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
+struct pid_namespace *copy_pid_ns(unsigned long flags,
+ struct user_namespace *user_ns, struct pid_namespace *old_ns)
{
if (!(flags & CLONE_NEWPID))
return get_pid_ns(old_ns);
- if (flags & (CLONE_THREAD|CLONE_PARENT))
+ if (task_active_pid_ns(current) != old_ns)
return ERR_PTR(-EINVAL);
- return create_pid_namespace(old_ns);
+ return create_pid_namespace(user_ns, old_ns);
}
static void free_pid_ns(struct kref *kref)
int rc;
struct task_struct *task, *me = current;
+ /* Don't allow any more processes into the pid namespace */
+ disable_pid_allocation(pid_ns);
+
/* Ignore SIGCHLD causing any terminated children to autoreap */
spin_lock_irq(&me->sighand->siglock);
me->sighand->action[SIGCHLD - 1].sa.sa_handler = SIG_IGN;
/*
* sys_wait4() above can't reap the TASK_DEAD children.
- * Make sure they all go away, see __unhash_process().
+ * Make sure they all go away, see free_pid().
*/
for (;;) {
- bool need_wait = false;
-
- read_lock(&tasklist_lock);
- if (!list_empty(¤t->children)) {
- __set_current_state(TASK_UNINTERRUPTIBLE);
- need_wait = true;
- }
- read_unlock(&tasklist_lock);
-
- if (!need_wait)
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (pid_ns->nr_hashed == 1)
break;
schedule();
}
+ __set_current_state(TASK_RUNNING);
if (pid_ns->reboot)
current->signal->group_exit_code = pid_ns->reboot;
static int pid_ns_ctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
+ struct pid_namespace *pid_ns = task_active_pid_ns(current);
struct ctl_table tmp = *table;
- if (write && !capable(CAP_SYS_ADMIN))
+ if (write && !ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
/*
* it should synchronize its usage with external means.
*/
- tmp.data = ¤t->nsproxy->pid_ns->last_pid;
+ tmp.data = &pid_ns->last_pid;
return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
}
return 0;
}
+static void *pidns_get(struct task_struct *task)
+{
+ struct pid_namespace *ns;
+
+ rcu_read_lock();
+ ns = get_pid_ns(task_active_pid_ns(task));
+ rcu_read_unlock();
+
+ return ns;
+}
+
+static void pidns_put(void *ns)
+{
+ put_pid_ns(ns);
+}
+
+static int pidns_install(struct nsproxy *nsproxy, void *ns)
+{
+ struct pid_namespace *active = task_active_pid_ns(current);
+ struct pid_namespace *ancestor, *new = ns;
+
+ if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
+ !nsown_capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /*
+ * Only allow entering the current active pid namespace
+ * or a child of the current active pid namespace.
+ *
+ * This is required for fork to return a usable pid value and
+ * this maintains the property that processes and their
+ * children can not escape their current pid namespace.
+ */
+ if (new->level < active->level)
+ return -EINVAL;
+
+ ancestor = new;
+ while (ancestor->level > active->level)
+ ancestor = ancestor->parent;
+ if (ancestor != active)
+ return -EINVAL;
+
+ put_pid_ns(nsproxy->pid_ns);
+ nsproxy->pid_ns = get_pid_ns(new);
+ return 0;
+}
+
+static unsigned int pidns_inum(void *ns)
+{
+ struct pid_namespace *pid_ns = ns;
+ return pid_ns->proc_inum;
+}
+
+const struct proc_ns_operations pidns_operations = {
+ .name = "pid",
+ .type = CLONE_NEWPID,
+ .get = pidns_get,
+ .put = pidns_put,
+ .install = pidns_install,
+ .inum = pidns_inum,
+};
+
static __init int pid_namespaces_init(void)
{
pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC);
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