linux-stable.git/include/net/net_namespace.h, branch linux-6.14.y

net: Add net_passive_inc() and net_passive_dec().

2025-02-19T02:33:29+00:00

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

net: add dev_net_rcu() helper

2025-02-07T00:14:14+00:00

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

net: expedite synchronize_net() for cleanup_net()

2025-01-16T03:17:03+00:00

cleanup_net() is the single thread responsible
for netns dismantles, and a serious bottleneck.

Before we can get per-netns RTNL, make sure
all synchronize_net() called from this thread
are using rcu_synchronize_expedited().

v3: deal with CONFIG_NET_NS=n

Signed-off-by: Eric Dumazet 
Reviewed-by: Jesse Brandeburg 
Link: https://patch.msgid.link/20250114205531.967841-2-edumazet@google.com
Signed-off-by: Jakub Kicinski

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