linux/kernel/pid_namespace.c
Linus Torvalds cb8e59cc87 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from David Miller:

 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz
    Augusto von Dentz.

 2) Add GSO partial support to igc, from Sasha Neftin.

 3) Several cleanups and improvements to r8169 from Heiner Kallweit.

 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a
    device self-test. From Andrew Lunn.

 5) Start moving away from custom driver versions, use the globally
    defined kernel version instead, from Leon Romanovsky.

 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin.

 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet.

 8) Add sriov and vf support to hinic, from Luo bin.

 9) Support Media Redundancy Protocol (MRP) in the bridging code, from
    Horatiu Vultur.

10) Support netmap in the nft_nat code, from Pablo Neira Ayuso.

11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina
    Dubroca. Also add ipv6 support for espintcp.

12) Lots of ReST conversions of the networking documentation, from Mauro
    Carvalho Chehab.

13) Support configuration of ethtool rxnfc flows in bcmgenet driver,
    from Doug Berger.

14) Allow to dump cgroup id and filter by it in inet_diag code, from
    Dmitry Yakunin.

15) Add infrastructure to export netlink attribute policies to
    userspace, from Johannes Berg.

16) Several optimizations to sch_fq scheduler, from Eric Dumazet.

17) Fallback to the default qdisc if qdisc init fails because otherwise
    a packet scheduler init failure will make a device inoperative. From
    Jesper Dangaard Brouer.

18) Several RISCV bpf jit optimizations, from Luke Nelson.

19) Correct the return type of the ->ndo_start_xmit() method in several
    drivers, it's netdev_tx_t but many drivers were using
    'int'. From Yunjian Wang.

20) Add an ethtool interface for PHY master/slave config, from Oleksij
    Rempel.

21) Add BPF iterators, from Yonghang Song.

22) Add cable test infrastructure, including ethool interfaces, from
    Andrew Lunn. Marvell PHY driver is the first to support this
    facility.

23) Remove zero-length arrays all over, from Gustavo A. R. Silva.

24) Calculate and maintain an explicit frame size in XDP, from Jesper
    Dangaard Brouer.

25) Add CAP_BPF, from Alexei Starovoitov.

26) Support terse dumps in the packet scheduler, from Vlad Buslov.

27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei.

28) Add devm_register_netdev(), from Bartosz Golaszewski.

29) Minimize qdisc resets, from Cong Wang.

30) Get rid of kernel_getsockopt and kernel_setsockopt in order to
    eliminate set_fs/get_fs calls. From Christoph Hellwig.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits)
  selftests: net: ip_defrag: ignore EPERM
  net_failover: fixed rollback in net_failover_open()
  Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv"
  Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv"
  vmxnet3: allow rx flow hash ops only when rss is enabled
  hinic: add set_channels ethtool_ops support
  selftests/bpf: Add a default $(CXX) value
  tools/bpf: Don't use $(COMPILE.c)
  bpf, selftests: Use bpf_probe_read_kernel
  s390/bpf: Use bcr 0,%0 as tail call nop filler
  s390/bpf: Maintain 8-byte stack alignment
  selftests/bpf: Fix verifier test
  selftests/bpf: Fix sample_cnt shared between two threads
  bpf, selftests: Adapt cls_redirect to call csum_level helper
  bpf: Add csum_level helper for fixing up csum levels
  bpf: Fix up bpf_skb_adjust_room helper's skb csum setting
  sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf()
  crypto/chtls: IPv6 support for inline TLS
  Crypto/chcr: Fixes a coccinile check error
  Crypto/chcr: Fixes compilations warnings
  ...
2020-06-03 16:27:18 -07:00

468 lines
11 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>
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, 0);
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;
kref_init(&ns->kref);
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;
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);
}
static void free_pid_ns(struct kref *kref)
{
struct pid_namespace *ns;
ns = container_of(kref, struct pid_namespace, kref);
destroy_pid_namespace(ns);
}
void put_pid_ns(struct pid_namespace *ns)
{
struct pid_namespace *parent;
while (ns != &init_pid_ns) {
parent = ns->parent;
if (!kref_put(&ns->kref, free_pid_ns))
break;
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 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;
schedule();
}
__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 && !ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN))
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);
#ifdef CONFIG_CHECKPOINT_RESTORE
register_sysctl_paths(kern_path, pid_ns_ctl_table);
#endif
return 0;
}
__initcall(pid_namespaces_init);