mirror of
https://github.com/torvalds/linux.git
synced 2024-11-24 05:02:12 +00:00
3822a7c409
F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY/PoPQAKCRDdBJ7gKXxA jlvpAPsFECUBBl20qSue2zCYWnHC7Yk4q9ytTkPB/MMDrFEN9wD/SNKEm2UoK6/K DmxHkn0LAitGgJRS/W9w81yrgig9tAQ= =MlGs -----END PGP SIGNATURE----- Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Daniel Verkamp has contributed a memfd series ("mm/memfd: add F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". * tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits) include/linux/migrate.h: remove unneeded externs mm/memory_hotplug: cleanup return value handing in do_migrate_range() mm/uffd: fix comment in handling pte markers mm: change to return bool for isolate_movable_page() mm: hugetlb: change to return bool for isolate_hugetlb() mm: change to return bool for isolate_lru_page() mm: change to return bool for folio_isolate_lru() objtool: add UACCESS exceptions for __tsan_volatile_read/write kmsan: disable ftrace in kmsan core code kasan: mark addr_has_metadata __always_inline mm: memcontrol: rename memcg_kmem_enabled() sh: initialize max_mapnr m68k/nommu: add missing definition of ARCH_PFN_OFFSET mm: percpu: fix incorrect size in pcpu_obj_full_size() maple_tree: reduce stack usage with gcc-9 and earlier mm: page_alloc: call panic() when memoryless node allocation fails mm: multi-gen LRU: avoid futile retries migrate_pages: move THP/hugetlb migration support check to simplify code migrate_pages: batch flushing TLB migrate_pages: share more code between _unmap and _move ...
484 lines
12 KiB
C
484 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Pid namespaces
|
|
*
|
|
* Authors:
|
|
* (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc.
|
|
* (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM
|
|
* Many thanks to Oleg Nesterov for comments and help
|
|
*
|
|
*/
|
|
|
|
#include <linux/pid.h>
|
|
#include <linux/pid_namespace.h>
|
|
#include <linux/user_namespace.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/cred.h>
|
|
#include <linux/err.h>
|
|
#include <linux/acct.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/proc_ns.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/export.h>
|
|
#include <linux/sched/task.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/idr.h>
|
|
#include "pid_sysctl.h"
|
|
|
|
static DEFINE_MUTEX(pid_caches_mutex);
|
|
static struct kmem_cache *pid_ns_cachep;
|
|
/* Write once array, filled from the beginning. */
|
|
static struct kmem_cache *pid_cache[MAX_PID_NS_LEVEL];
|
|
|
|
/*
|
|
* creates the kmem cache to allocate pids from.
|
|
* @level: pid namespace level
|
|
*/
|
|
|
|
static struct kmem_cache *create_pid_cachep(unsigned int level)
|
|
{
|
|
/* Level 0 is init_pid_ns.pid_cachep */
|
|
struct kmem_cache **pkc = &pid_cache[level - 1];
|
|
struct kmem_cache *kc;
|
|
char name[4 + 10 + 1];
|
|
unsigned int len;
|
|
|
|
kc = READ_ONCE(*pkc);
|
|
if (kc)
|
|
return kc;
|
|
|
|
snprintf(name, sizeof(name), "pid_%u", level + 1);
|
|
len = sizeof(struct pid) + level * sizeof(struct upid);
|
|
mutex_lock(&pid_caches_mutex);
|
|
/* Name collision forces to do allocation under mutex. */
|
|
if (!*pkc)
|
|
*pkc = kmem_cache_create(name, len, 0,
|
|
SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT, NULL);
|
|
mutex_unlock(&pid_caches_mutex);
|
|
/* current can fail, but someone else can succeed. */
|
|
return READ_ONCE(*pkc);
|
|
}
|
|
|
|
static struct ucounts *inc_pid_namespaces(struct user_namespace *ns)
|
|
{
|
|
return inc_ucount(ns, current_euid(), UCOUNT_PID_NAMESPACES);
|
|
}
|
|
|
|
static void dec_pid_namespaces(struct ucounts *ucounts)
|
|
{
|
|
dec_ucount(ucounts, UCOUNT_PID_NAMESPACES);
|
|
}
|
|
|
|
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;
|
|
struct ucounts *ucounts;
|
|
int err;
|
|
|
|
err = -EINVAL;
|
|
if (!in_userns(parent_pid_ns->user_ns, user_ns))
|
|
goto out;
|
|
|
|
err = -ENOSPC;
|
|
if (level > MAX_PID_NS_LEVEL)
|
|
goto out;
|
|
ucounts = inc_pid_namespaces(user_ns);
|
|
if (!ucounts)
|
|
goto out;
|
|
|
|
err = -ENOMEM;
|
|
ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
|
|
if (ns == NULL)
|
|
goto out_dec;
|
|
|
|
idr_init(&ns->idr);
|
|
|
|
ns->pid_cachep = create_pid_cachep(level);
|
|
if (ns->pid_cachep == NULL)
|
|
goto out_free_idr;
|
|
|
|
err = ns_alloc_inum(&ns->ns);
|
|
if (err)
|
|
goto out_free_idr;
|
|
ns->ns.ops = &pidns_operations;
|
|
|
|
refcount_set(&ns->ns.count, 1);
|
|
ns->level = level;
|
|
ns->parent = get_pid_ns(parent_pid_ns);
|
|
ns->user_ns = get_user_ns(user_ns);
|
|
ns->ucounts = ucounts;
|
|
ns->pid_allocated = PIDNS_ADDING;
|
|
|
|
initialize_memfd_noexec_scope(ns);
|
|
|
|
return ns;
|
|
|
|
out_free_idr:
|
|
idr_destroy(&ns->idr);
|
|
kmem_cache_free(pid_ns_cachep, ns);
|
|
out_dec:
|
|
dec_pid_namespaces(ucounts);
|
|
out:
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
static void delayed_free_pidns(struct rcu_head *p)
|
|
{
|
|
struct pid_namespace *ns = container_of(p, struct pid_namespace, rcu);
|
|
|
|
dec_pid_namespaces(ns->ucounts);
|
|
put_user_ns(ns->user_ns);
|
|
|
|
kmem_cache_free(pid_ns_cachep, ns);
|
|
}
|
|
|
|
static void destroy_pid_namespace(struct pid_namespace *ns)
|
|
{
|
|
ns_free_inum(&ns->ns);
|
|
|
|
idr_destroy(&ns->idr);
|
|
call_rcu(&ns->rcu, delayed_free_pidns);
|
|
}
|
|
|
|
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 (task_active_pid_ns(current) != old_ns)
|
|
return ERR_PTR(-EINVAL);
|
|
return create_pid_namespace(user_ns, old_ns);
|
|
}
|
|
|
|
void put_pid_ns(struct pid_namespace *ns)
|
|
{
|
|
struct pid_namespace *parent;
|
|
|
|
while (ns != &init_pid_ns) {
|
|
parent = ns->parent;
|
|
if (!refcount_dec_and_test(&ns->ns.count))
|
|
break;
|
|
destroy_pid_namespace(ns);
|
|
ns = parent;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(put_pid_ns);
|
|
|
|
void zap_pid_ns_processes(struct pid_namespace *pid_ns)
|
|
{
|
|
int nr;
|
|
int rc;
|
|
struct task_struct *task, *me = current;
|
|
int init_pids = thread_group_leader(me) ? 1 : 2;
|
|
struct pid *pid;
|
|
|
|
/* Don't allow any more processes into the pid namespace */
|
|
disable_pid_allocation(pid_ns);
|
|
|
|
/*
|
|
* Ignore SIGCHLD causing any terminated children to autoreap.
|
|
* This speeds up the namespace shutdown, plus see the comment
|
|
* below.
|
|
*/
|
|
spin_lock_irq(&me->sighand->siglock);
|
|
me->sighand->action[SIGCHLD - 1].sa.sa_handler = SIG_IGN;
|
|
spin_unlock_irq(&me->sighand->siglock);
|
|
|
|
/*
|
|
* The last thread in the cgroup-init thread group is terminating.
|
|
* Find remaining pid_ts in the namespace, signal and wait for them
|
|
* to exit.
|
|
*
|
|
* Note: This signals each threads in the namespace - even those that
|
|
* belong to the same thread group, To avoid this, we would have
|
|
* to walk the entire tasklist looking a processes in this
|
|
* namespace, but that could be unnecessarily expensive if the
|
|
* pid namespace has just a few processes. Or we need to
|
|
* maintain a tasklist for each pid namespace.
|
|
*
|
|
*/
|
|
rcu_read_lock();
|
|
read_lock(&tasklist_lock);
|
|
nr = 2;
|
|
idr_for_each_entry_continue(&pid_ns->idr, pid, nr) {
|
|
task = pid_task(pid, PIDTYPE_PID);
|
|
if (task && !__fatal_signal_pending(task))
|
|
group_send_sig_info(SIGKILL, SEND_SIG_PRIV, task, PIDTYPE_MAX);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
rcu_read_unlock();
|
|
|
|
/*
|
|
* Reap the EXIT_ZOMBIE children we had before we ignored SIGCHLD.
|
|
* kernel_wait4() will also block until our children traced from the
|
|
* parent namespace are detached and become EXIT_DEAD.
|
|
*/
|
|
do {
|
|
clear_thread_flag(TIF_SIGPENDING);
|
|
rc = kernel_wait4(-1, NULL, __WALL, NULL);
|
|
} while (rc != -ECHILD);
|
|
|
|
/*
|
|
* kernel_wait4() misses EXIT_DEAD children, and EXIT_ZOMBIE
|
|
* process whose parents processes are outside of the pid
|
|
* namespace. Such processes are created with setns()+fork().
|
|
*
|
|
* If those EXIT_ZOMBIE processes are not reaped by their
|
|
* parents before their parents exit, they will be reparented
|
|
* to pid_ns->child_reaper. Thus pidns->child_reaper needs to
|
|
* stay valid until they all go away.
|
|
*
|
|
* The code relies on the pid_ns->child_reaper ignoring
|
|
* SIGCHILD to cause those EXIT_ZOMBIE processes to be
|
|
* autoreaped if reparented.
|
|
*
|
|
* Semantically it is also desirable to wait for EXIT_ZOMBIE
|
|
* processes before allowing the child_reaper to be reaped, as
|
|
* that gives the invariant that when the init process of a
|
|
* pid namespace is reaped all of the processes in the pid
|
|
* namespace are gone.
|
|
*
|
|
* Once all of the other tasks are gone from the pid_namespace
|
|
* free_pid() will awaken this task.
|
|
*/
|
|
for (;;) {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
if (pid_ns->pid_allocated == init_pids)
|
|
break;
|
|
/*
|
|
* Release tasks_rcu_exit_srcu to avoid following deadlock:
|
|
*
|
|
* 1) TASK A unshare(CLONE_NEWPID)
|
|
* 2) TASK A fork() twice -> TASK B (child reaper for new ns)
|
|
* and TASK C
|
|
* 3) TASK B exits, kills TASK C, waits for TASK A to reap it
|
|
* 4) TASK A calls synchronize_rcu_tasks()
|
|
* -> synchronize_srcu(tasks_rcu_exit_srcu)
|
|
* 5) *DEADLOCK*
|
|
*
|
|
* It is considered safe to release tasks_rcu_exit_srcu here
|
|
* because we assume the current task can not be concurrently
|
|
* reaped at this point.
|
|
*/
|
|
exit_tasks_rcu_stop();
|
|
schedule();
|
|
exit_tasks_rcu_start();
|
|
}
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
if (pid_ns->reboot)
|
|
current->signal->group_exit_code = pid_ns->reboot;
|
|
|
|
acct_exit_ns(pid_ns);
|
|
return;
|
|
}
|
|
|
|
#ifdef CONFIG_CHECKPOINT_RESTORE
|
|
static int pid_ns_ctl_handler(struct ctl_table *table, int write,
|
|
void *buffer, size_t *lenp, loff_t *ppos)
|
|
{
|
|
struct pid_namespace *pid_ns = task_active_pid_ns(current);
|
|
struct ctl_table tmp = *table;
|
|
int ret, next;
|
|
|
|
if (write && !checkpoint_restore_ns_capable(pid_ns->user_ns))
|
|
return -EPERM;
|
|
|
|
/*
|
|
* Writing directly to ns' last_pid field is OK, since this field
|
|
* is volatile in a living namespace anyway and a code writing to
|
|
* it should synchronize its usage with external means.
|
|
*/
|
|
|
|
next = idr_get_cursor(&pid_ns->idr) - 1;
|
|
|
|
tmp.data = &next;
|
|
ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
|
|
if (!ret && write)
|
|
idr_set_cursor(&pid_ns->idr, next + 1);
|
|
|
|
return ret;
|
|
}
|
|
|
|
extern int pid_max;
|
|
static struct ctl_table pid_ns_ctl_table[] = {
|
|
{
|
|
.procname = "ns_last_pid",
|
|
.maxlen = sizeof(int),
|
|
.mode = 0666, /* permissions are checked in the handler */
|
|
.proc_handler = pid_ns_ctl_handler,
|
|
.extra1 = SYSCTL_ZERO,
|
|
.extra2 = &pid_max,
|
|
},
|
|
{ }
|
|
};
|
|
static struct ctl_path kern_path[] = { { .procname = "kernel", }, { } };
|
|
#endif /* CONFIG_CHECKPOINT_RESTORE */
|
|
|
|
int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
|
|
{
|
|
if (pid_ns == &init_pid_ns)
|
|
return 0;
|
|
|
|
switch (cmd) {
|
|
case LINUX_REBOOT_CMD_RESTART2:
|
|
case LINUX_REBOOT_CMD_RESTART:
|
|
pid_ns->reboot = SIGHUP;
|
|
break;
|
|
|
|
case LINUX_REBOOT_CMD_POWER_OFF:
|
|
case LINUX_REBOOT_CMD_HALT:
|
|
pid_ns->reboot = SIGINT;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
read_lock(&tasklist_lock);
|
|
send_sig(SIGKILL, pid_ns->child_reaper, 1);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
do_exit(0);
|
|
|
|
/* Not reached */
|
|
return 0;
|
|
}
|
|
|
|
static inline struct pid_namespace *to_pid_ns(struct ns_common *ns)
|
|
{
|
|
return container_of(ns, struct pid_namespace, ns);
|
|
}
|
|
|
|
static struct ns_common *pidns_get(struct task_struct *task)
|
|
{
|
|
struct pid_namespace *ns;
|
|
|
|
rcu_read_lock();
|
|
ns = task_active_pid_ns(task);
|
|
if (ns)
|
|
get_pid_ns(ns);
|
|
rcu_read_unlock();
|
|
|
|
return ns ? &ns->ns : NULL;
|
|
}
|
|
|
|
static struct ns_common *pidns_for_children_get(struct task_struct *task)
|
|
{
|
|
struct pid_namespace *ns = NULL;
|
|
|
|
task_lock(task);
|
|
if (task->nsproxy) {
|
|
ns = task->nsproxy->pid_ns_for_children;
|
|
get_pid_ns(ns);
|
|
}
|
|
task_unlock(task);
|
|
|
|
if (ns) {
|
|
read_lock(&tasklist_lock);
|
|
if (!ns->child_reaper) {
|
|
put_pid_ns(ns);
|
|
ns = NULL;
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
|
|
return ns ? &ns->ns : NULL;
|
|
}
|
|
|
|
static void pidns_put(struct ns_common *ns)
|
|
{
|
|
put_pid_ns(to_pid_ns(ns));
|
|
}
|
|
|
|
static int pidns_install(struct nsset *nsset, struct ns_common *ns)
|
|
{
|
|
struct nsproxy *nsproxy = nsset->nsproxy;
|
|
struct pid_namespace *active = task_active_pid_ns(current);
|
|
struct pid_namespace *ancestor, *new = to_pid_ns(ns);
|
|
|
|
if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
|
|
!ns_capable(nsset->cred->user_ns, 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_for_children);
|
|
nsproxy->pid_ns_for_children = get_pid_ns(new);
|
|
return 0;
|
|
}
|
|
|
|
static struct ns_common *pidns_get_parent(struct ns_common *ns)
|
|
{
|
|
struct pid_namespace *active = task_active_pid_ns(current);
|
|
struct pid_namespace *pid_ns, *p;
|
|
|
|
/* See if the parent is in the current namespace */
|
|
pid_ns = p = to_pid_ns(ns)->parent;
|
|
for (;;) {
|
|
if (!p)
|
|
return ERR_PTR(-EPERM);
|
|
if (p == active)
|
|
break;
|
|
p = p->parent;
|
|
}
|
|
|
|
return &get_pid_ns(pid_ns)->ns;
|
|
}
|
|
|
|
static struct user_namespace *pidns_owner(struct ns_common *ns)
|
|
{
|
|
return to_pid_ns(ns)->user_ns;
|
|
}
|
|
|
|
const struct proc_ns_operations pidns_operations = {
|
|
.name = "pid",
|
|
.type = CLONE_NEWPID,
|
|
.get = pidns_get,
|
|
.put = pidns_put,
|
|
.install = pidns_install,
|
|
.owner = pidns_owner,
|
|
.get_parent = pidns_get_parent,
|
|
};
|
|
|
|
const struct proc_ns_operations pidns_for_children_operations = {
|
|
.name = "pid_for_children",
|
|
.real_ns_name = "pid",
|
|
.type = CLONE_NEWPID,
|
|
.get = pidns_for_children_get,
|
|
.put = pidns_put,
|
|
.install = pidns_install,
|
|
.owner = pidns_owner,
|
|
.get_parent = pidns_get_parent,
|
|
};
|
|
|
|
static __init int pid_namespaces_init(void)
|
|
{
|
|
pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC | SLAB_ACCOUNT);
|
|
|
|
#ifdef CONFIG_CHECKPOINT_RESTORE
|
|
register_sysctl_paths(kern_path, pid_ns_ctl_table);
|
|
#endif
|
|
|
|
register_pid_ns_sysctl_table_vm();
|
|
return 0;
|
|
}
|
|
|
|
__initcall(pid_namespaces_init);
|