Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 592 insertions, 0 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
new file mode 100644
index 000000000..a487ff241
--- /dev/null
+++ b/kernel/nsproxy.c
@@ -0,0 +1,592 @@
+// 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;
+
+	if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+			      CLONE_NEWPID | CLONE_NEWNET |
+			      CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
+		if ((flags & CLONE_VM) ||
+		    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);
+
+	if ((flags & CLONE_VM) == 0)
+		timens_on_fork(new_ns, tsk);
+
+	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)
+		put_nsproxy(ns);
+}
+
+void exit_task_namespaces(struct task_struct *p)
+{
+	switch_task_namespaces(p, NULL);
+}
+
+int exec_task_namespaces(void)
+{
+	struct task_struct *tsk = current;
+	struct nsproxy *new;
+
+	if (tsk->nsproxy->time_ns_for_children == tsk->nsproxy->time_ns)
+		return 0;
+
+	new = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
+	if (IS_ERR(new))
+		return PTR_ERR(new);
+
+	timens_on_fork(new, tsk);
+	switch_task_namespaces(tsk, new);
+	return 0;
+}
+
+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|SLAB_ACCOUNT);
+	return 0;
+}