linux-stable.git/include/net/net_namespace.h, branch linux-6.13.y

net: Add net_passive_inc() and net_passive_dec().

2025-03-07T17:26:57+00:00

[ Upstream commit e57a6320215c3967f51ab0edeff87db2095440e4 ]

net_drop_ns() is NULL when CONFIG_NET_NS is disabled.

The next patch introduces a function that increments
and decrements net->passive.

As a prep, let's rename and export net_free() to
net_passive_dec() and add net_passive_inc().

Suggested-by: Eric Dumazet 
Link: https://lore.kernel.org/netdev/CANn89i+oUCt2VGvrbrweniTendZFEh+nwS=uonc004-aPkWy-Q@mail.gmail.com/
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20250217191129.19967-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 5c70eb5c593d ("net: better track kernel sockets lifetime")
Signed-off-by: Sasha Levin

net: add dev_net_rcu() helper

2025-02-21T13:11:14+00:00

[ Upstream commit 482ad2a4ace2740ca0ff1cbc8f3c7f862f3ab507 ]

dev->nd_net can change, readers should either
use rcu_read_lock() or RTNL.

We currently use a generic helper, dev_net() with
no debugging support. We probably have many hidden bugs.

Add dev_net_rcu() helper for callers using rcu_read_lock()
protection.

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250205155120.1676781-2-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 71b8471c93fa ("ipv4: use RCU protection in ipv4_default_advmss()")
Signed-off-by: Sasha Levin

net: defer final 'struct net' free in netns dismantle

2024-12-07T01:45:08+00:00

Ilya reported a slab-use-after-free in dst_destroy [1]

Issue is in xfrm6_net_init() and xfrm4_net_init() :

They copy xfrm[46]_dst_ops_template into net->xfrm.xfrm[46]_dst_ops.

But net structure might be freed before all the dst callbacks are
called. So when dst_destroy() calls later :

if (dst->ops->destroy)
    dst->ops->destroy(dst);

dst->ops points to the old net->xfrm.xfrm[46]_dst_ops, which has been freed.

See a relevant issue fixed in :

ac888d58869b ("net: do not delay dst_entries_add() in dst_release()")

A fix is to queue the 'struct net' to be freed after one
another cleanup_net() round (and existing rcu_barrier())

[1]

BUG: KASAN: slab-use-after-free in dst_destroy (net/core/dst.c:112)
Read of size 8 at addr ffff8882137ccab0 by task swapper/37/0
Dec 03 05:46:18 kernel:
CPU: 37 UID: 0 PID: 0 Comm: swapper/37 Kdump: loaded Not tainted 6.12.0 #67
Hardware name: Red Hat KVM/RHEL, BIOS 1.16.1-1.el9 04/01/2014
Call Trace:
 
dump_stack_lvl (lib/dump_stack.c:124)
print_address_description.constprop.0 (mm/kasan/report.c:378)
? dst_destroy (net/core/dst.c:112)
print_report (mm/kasan/report.c:489)
? dst_destroy (net/core/dst.c:112)
? kasan_addr_to_slab (mm/kasan/common.c:37)
kasan_report (mm/kasan/report.c:603)
? dst_destroy (net/core/dst.c:112)
? rcu_do_batch (kernel/rcu/tree.c:2567)
dst_destroy (net/core/dst.c:112)
rcu_do_batch (kernel/rcu/tree.c:2567)
? __pfx_rcu_do_batch (kernel/rcu/tree.c:2491)
? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406)
rcu_core (kernel/rcu/tree.c:2825)
handle_softirqs (kernel/softirq.c:554)
__irq_exit_rcu (kernel/softirq.c:589 kernel/softirq.c:428 kernel/softirq.c:637)
irq_exit_rcu (kernel/softirq.c:651)
sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049)
 
 
asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702)
RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:92 arch/x86/kernel/process.c:743)
Code: 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 6e ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 0f 00 2d c7 c9 27 00 fb f4  c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90
RSP: 0018:ffff888100d2fe00 EFLAGS: 00000246
RAX: 00000000001870ed RBX: 1ffff110201a5fc2 RCX: ffffffffb61a3e46
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffb3d4d123
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed11c7e1835d
R10: ffff888e3f0c1aeb R11: 0000000000000000 R12: 0000000000000000
R13: ffff888100d20000 R14: dffffc0000000000 R15: 0000000000000000
? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:148)
? cpuidle_idle_call (kernel/sched/idle.c:186)
default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118)
cpuidle_idle_call (kernel/sched/idle.c:186)
? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168)
? lock_release (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5848)
? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59)
do_idle (kernel/sched/idle.c:326)
cpu_startup_entry (kernel/sched/idle.c:423 (discriminator 1))
start_secondary (arch/x86/kernel/smpboot.c:202 arch/x86/kernel/smpboot.c:282)
? __pfx_start_secondary (arch/x86/kernel/smpboot.c:232)
? soft_restart_cpu (arch/x86/kernel/head_64.S:452)
common_startup_64 (arch/x86/kernel/head_64.S:414)
 
Dec 03 05:46:18 kernel:
Allocated by task 12184:
kasan_save_stack (mm/kasan/common.c:48)
kasan_save_track (./arch/x86/include/asm/current.h:49 mm/kasan/common.c:60 mm/kasan/common.c:69)
__kasan_slab_alloc (mm/kasan/common.c:319 mm/kasan/common.c:345)
kmem_cache_alloc_noprof (mm/slub.c:4085 mm/slub.c:4134 mm/slub.c:4141)
copy_net_ns (net/core/net_namespace.c:421 net/core/net_namespace.c:480)
create_new_namespaces (kernel/nsproxy.c:110)
unshare_nsproxy_namespaces (kernel/nsproxy.c:228 (discriminator 4))
ksys_unshare (kernel/fork.c:3313)
__x64_sys_unshare (kernel/fork.c:3382)
do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
Dec 03 05:46:18 kernel:
Freed by task 11:
kasan_save_stack (mm/kasan/common.c:48)
kasan_save_track (./arch/x86/include/asm/current.h:49 mm/kasan/common.c:60 mm/kasan/common.c:69)
kasan_save_free_info (mm/kasan/generic.c:582)
__kasan_slab_free (mm/kasan/common.c:271)
kmem_cache_free (mm/slub.c:4579 mm/slub.c:4681)
cleanup_net (net/core/net_namespace.c:456 net/core/net_namespace.c:446 net/core/net_namespace.c:647)
process_one_work (kernel/workqueue.c:3229)
worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
kthread (kernel/kthread.c:389)
ret_from_fork (arch/x86/kernel/process.c:147)
ret_from_fork_asm (arch/x86/entry/entry_64.S:257)
Dec 03 05:46:18 kernel:
Last potentially related work creation:
kasan_save_stack (mm/kasan/common.c:48)
__kasan_record_aux_stack (mm/kasan/generic.c:541)
insert_work (./include/linux/instrumented.h:68 ./include/asm-generic/bitops/instrumented-non-atomic.h:141 kernel/workqueue.c:788 kernel/workqueue.c:795 kernel/workqueue.c:2186)
__queue_work (kernel/workqueue.c:2340)
queue_work_on (kernel/workqueue.c:2391)
xfrm_policy_insert (net/xfrm/xfrm_policy.c:1610)
xfrm_add_policy (net/xfrm/xfrm_user.c:2116)
xfrm_user_rcv_msg (net/xfrm/xfrm_user.c:3321)
netlink_rcv_skb (net/netlink/af_netlink.c:2536)
xfrm_netlink_rcv (net/xfrm/xfrm_user.c:3344)
netlink_unicast (net/netlink/af_netlink.c:1316 net/netlink/af_netlink.c:1342)
netlink_sendmsg (net/netlink/af_netlink.c:1886)
sock_write_iter (net/socket.c:729 net/socket.c:744 net/socket.c:1165)
vfs_write (fs/read_write.c:590 fs/read_write.c:683)
ksys_write (fs/read_write.c:736)
do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
Dec 03 05:46:18 kernel:
Second to last potentially related work creation:
kasan_save_stack (mm/kasan/common.c:48)
__kasan_record_aux_stack (mm/kasan/generic.c:541)
insert_work (./include/linux/instrumented.h:68 ./include/asm-generic/bitops/instrumented-non-atomic.h:141 kernel/workqueue.c:788 kernel/workqueue.c:795 kernel/workqueue.c:2186)
__queue_work (kernel/workqueue.c:2340)
queue_work_on (kernel/workqueue.c:2391)
__xfrm_state_insert (./include/linux/workqueue.h:723 net/xfrm/xfrm_state.c:1150 net/xfrm/xfrm_state.c:1145 net/xfrm/xfrm_state.c:1513)
xfrm_state_update (./include/linux/spinlock.h:396 net/xfrm/xfrm_state.c:1940)
xfrm_add_sa (net/xfrm/xfrm_user.c:912)
xfrm_user_rcv_msg (net/xfrm/xfrm_user.c:3321)
netlink_rcv_skb (net/netlink/af_netlink.c:2536)
xfrm_netlink_rcv (net/xfrm/xfrm_user.c:3344)
netlink_unicast (net/netlink/af_netlink.c:1316 net/netlink/af_netlink.c:1342)
netlink_sendmsg (net/netlink/af_netlink.c:1886)
sock_write_iter (net/socket.c:729 net/socket.c:744 net/socket.c:1165)
vfs_write (fs/read_write.c:590 fs/read_write.c:683)
ksys_write (fs/read_write.c:736)
do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

Fixes: a8a572a6b5f2 ("xfrm: dst_entries_init() per-net dst_ops")
Reported-by: Ilya Maximets 
Closes: https://lore.kernel.org/netdev/CANn89iKKYDVpB=MtmfH7nyv2p=rJWSLedO5k7wSZgtY_tO8WQg@mail.gmail.com/T/#m02c98c3009fe66382b73cfb4db9cf1df6fab3fbf
Signed-off-by: Eric Dumazet 
Acked-by: Paolo Abeni 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20241204125455.3871859-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

ipmr: tune the ipmr_can_free_table() checks.

2024-12-05T02:49:16+00:00

Eric reported a syzkaller-triggered splat caused by recent ipmr changes:

WARNING: CPU: 2 PID: 6041 at net/ipv6/ip6mr.c:419
ip6mr_free_table+0xbd/0x120 net/ipv6/ip6mr.c:419
Modules linked in:
CPU: 2 UID: 0 PID: 6041 Comm: syz-executor183 Not tainted
6.12.0-syzkaller-10681-g65ae975e97d5 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ip6mr_free_table+0xbd/0x120 net/ipv6/ip6mr.c:419
Code: 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c
02 00 75 58 49 83 bc 24 c0 0e 00 00 00 74 09 e8 44 ef a9 f7 90 <0f> 0b
90 e8 3b ef a9 f7 48 8d 7b 38 e8 12 a3 96 f7 48 89 df be 0f
RSP: 0018:ffffc90004267bd8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88803c710000 RCX: ffffffff89e4d844
RDX: ffff88803c52c880 RSI: ffffffff89e4d87c RDI: ffff88803c578ec0
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff88803c578000
R13: ffff88803c710000 R14: ffff88803c710008 R15: dead000000000100
FS: 00007f7a855ee6c0(0000) GS:ffff88806a800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7a85689938 CR3: 000000003c492000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:

ip6mr_rules_exit+0x176/0x2d0 net/ipv6/ip6mr.c:283
ip6mr_net_exit_batch+0x53/0xa0 net/ipv6/ip6mr.c:1388
ops_exit_list+0x128/0x180 net/core/net_namespace.c:177
setup_net+0x4fe/0x860 net/core/net_namespace.c:394
copy_net_ns+0x2b4/0x6b0 net/core/net_namespace.c:500
create_new_namespaces+0x3ea/0xad0 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:228
ksys_unshare+0x45d/0xa40 kernel/fork.c:3334
__do_sys_unshare kernel/fork.c:3405 [inline]
__se_sys_unshare kernel/fork.c:3403 [inline]
__x64_sys_unshare+0x31/0x40 kernel/fork.c:3403
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7a856332d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 48 89 f8 48
89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d
01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7a855ee238 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f7a856bd308 RCX: 00007f7a856332d9
RDX: 00007f7a8560f8c6 RSI: 0000000000000000 RDI: 0000000062040200
RBP: 00007f7a856bd300 R08: 00007fff932160a7 R09: 00007f7a855ee6c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7a856bd30c
R13: 0000000000000000 R14: 00007fff93215fc0 R15: 00007fff932160a8


The root cause is a network namespace creation failing after successful
initialization of the ipmr subsystem. Such a case is not currently
matched by the ipmr_can_free_table() helper.

New namespaces are zeroed on allocation and inserted into net ns list
only after successful creation; when deleting an ipmr table, the list
next pointer can be NULL only on netns initialization failure.

Update the ipmr_can_free_table() checks leveraging such condition.

Reported-by: Eric Dumazet 
Reported-by: syzbot+6e8cb445d4b43d006e0c@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6e8cb445d4b43d006e0c
Fixes: 11b6e701bce9 ("ipmr: add debug check for mr table cleanup")
Signed-off-by: Paolo Abeni 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/8bde975e21bbca9d9c27e36209b2dd4f1d7a3f00.1733212078.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski

rtnetlink: Add per-netns RTNL.

2024-10-08T13:16:59+00:00

The goal is to break RTNL down into per-netns mutex.

This patch adds per-netns mutex and its helper functions, rtnl_net_lock()
and rtnl_net_unlock().

rtnl_net_lock() acquires the global RTNL and per-netns RTNL mutex, and
rtnl_net_unlock() releases them.

We will replace 800+ rtnl_lock() with rtnl_net_lock() and finally removes
rtnl_lock() in rtnl_net_lock().

When we need to nest per-netns RTNL mutex, we will use __rtnl_net_lock(),
and its locking order is defined by rtnl_net_lock_cmp_fn() as follows:

  1. init_net is first
  2. netns address ascending order

Note that the conversion will be done under CONFIG_DEBUG_NET_SMALL_RTNL
with LOCKDEP so that we can carefully add the extra mutex without slowing
down RTNL operations during conversion.

Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Signed-off-by: Paolo Abeni

net: Don't register pernet_operations if only one of id or size is specified.

2024-08-03T21:38:44+00:00

We can allocate per-netns memory for struct pernet_operations by specifying
id and size.

register_pernet_operations() assigns an id to pernet_operations and later
ops_init() allocates the specified size of memory as net->gen->ptr[id].

If id is missing, no memory is allocated.  If size is not specified,
pernet_operations just wastes an entry of net->gen->ptr[] for every netns.

net_generic is available only when both id and size are specified, so let's
ensure that.

While we are at it, we add const to both fields.

Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: David S. Miller

net: add exit_batch_rtnl() method

2024-02-08T02:55:10+00:00

Many (struct pernet_operations)->exit_batch() methods have
to acquire rtnl.

In presence of rtnl mutex pressure, this makes cleanup_net()
very slow.

This patch adds a new exit_batch_rtnl() method to reduce
number of rtnl acquisitions from cleanup_net().

exit_batch_rtnl() handlers are called while rtnl is locked,
and devices to be killed can be queued in a list provided
as their second argument.

A single unregister_netdevice_many() is called right
before rtnl is released.

exit_batch_rtnl() handlers are called before ->exit() and
->exit_batch() handlers.

Signed-off-by: Eric Dumazet 
Reviewed-by: Antoine Tenart 
Link: https://lore.kernel.org/r/20240206144313.2050392-2-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: make dev_unreg_count global

2024-02-04T16:08:21+00:00

We can use a global dev_unreg_count counter instead
of a per netns one.

As a bonus we can factorize the changes done on it
for bulk device removals.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: treat possible_net_t net pointer as an RCU one and add read_pnet_rcu()

2023-10-18T08:23:01+00:00

Make the net pointer stored in possible_net_t structure annotated as
an RCU pointer. Change the access helpers to treat it as such.
Introduce read_pnet_rcu() helper to allow caller to dereference
the net pointer under RCU read lock.

Signed-off-by: Jiri Pirko 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller

Merge tag 'sysctl-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

2023-08-30T00:39:15+00:00

Pull sysctl updates from Luis Chamberlain:
 "Long ago we set out to remove the kitchen sink on kernel/sysctl.c
  arrays and placings sysctls to their own sybsystem or file to help
  avoid merge conflicts. Matthew Wilcox pointed out though that if we're
  going to do that we might as well also *save* space while at it and
  try to remove the extra last sysctl entry added at the end of each
  array, a sentintel, instead of bloating the kernel by adding a new
  sentinel with each array moved.

  Doing that was not so trivial, and has required slowing down the moves
  of kernel/sysctl.c arrays and measuring the impact on size by each new
  move.

  The complex part of the effort to help reduce the size of each sysctl
  is being done by the patient work of el señor Don Joel Granados. A lot
  of this is truly painful code refactoring and testing and then trying
  to measure the savings of each move and removing the sentinels.
  Although Joel already has code which does most of this work,
  experience with sysctl moves in the past shows is we need to be
  careful due to the slew of odd build failures that are possible due to
  the amount of random Kconfig options sysctls use.

  To that end Joel's work is split by first addressing the major
  housekeeping needed to remove the sentinels, which is part of this
  merge request. The rest of the work to actually remove the sentinels
  will be done later in future kernel releases.

  The preliminary math is showing this will all help reduce the overall
  build time size of the kernel and run time memory consumed by the
  kernel by about ~64 bytes per array where we are able to remove each
  sentinel in the future. That also means there is no more bloating the
  kernel with the extra ~64 bytes per array moved as no new sentinels
  are created"

* tag 'sysctl-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  sysctl: Use ctl_table_size as stopping criteria for list macro
  sysctl: SIZE_MAX->ARRAY_SIZE in register_net_sysctl
  vrf: Update to register_net_sysctl_sz
  networking: Update to register_net_sysctl_sz
  netfilter: Update to register_net_sysctl_sz
  ax.25: Update to register_net_sysctl_sz
  sysctl: Add size to register_net_sysctl function
  sysctl: Add size arg to __register_sysctl_init
  sysctl: Add size to register_sysctl
  sysctl: Add a size arg to __register_sysctl_table
  sysctl: Add size argument to init_header
  sysctl: Add ctl_table_size to ctl_table_header
  sysctl: Use ctl_table_header in list_for_each_table_entry
  sysctl: Prefer ctl_table_header in proc_sysctl