netfilter: nf_tables: fix memleak in map from abort path

The delete set command does not rely on the transaction object for
element removal, therefore, a combination of delete element + delete set
from the abort path could result in restoring twice the refcount of the
mapping.

Check for inactive element in the next generation for the delete element
command in the abort path, skip restoring state if next generation bit
has been already cleared. This is similar to the activate logic using
the set walk iterator.

[ 6170.286929] ------------[ cut here ]------------
[ 6170.286939] WARNING: CPU: 6 PID: 790302 at net/netfilter/nf_tables_api.c:2086 nf_tables_chain_destroy+0x1f7/0x220 [nf_tables]
[ 6170.287071] Modules linked in: [...]
[ 6170.287633] CPU: 6 PID: 790302 Comm: kworker/6:2 Not tainted 6.9.0-rc3+ #365
[ 6170.287768] RIP: 0010:nf_tables_chain_destroy+0x1f7/0x220 [nf_tables]
[ 6170.287886] Code: df 48 8d 7d 58 e8 69 2e 3b df 48 8b 7d 58 e8 80 1b 37 df 48 8d 7d 68 e8 57 2e 3b df 48 8b 7d 68 e8 6e 1b 37 df 48 89 ef eb c4 <0f> 0b 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc 0f
[ 6170.287895] RSP: 0018:ffff888134b8fd08 EFLAGS: 00010202
[ 6170.287904] RAX: 0000000000000001 RBX: ffff888125bffb28 RCX: dffffc0000000000
[ 6170.287912] RDX: 0000000000000003 RSI: ffffffffa20298ab RDI: ffff88811ebe4750
[ 6170.287919] RBP: ffff88811ebe4700 R08: ffff88838e812650 R09: fffffbfff0623a55
[ 6170.287926] R10: ffffffff8311d2af R11: 0000000000000001 R12: ffff888125bffb10
[ 6170.287933] R13: ffff888125bffb10 R14: dead000000000122 R15: dead000000000100
[ 6170.287940] FS: 0000000000000000(0000) GS:ffff888390b00000(0000) knlGS:0000000000000000
[ 6170.287948] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 6170.287955] CR2: 00007fd31fc00710 CR3: 0000000133f60004 CR4: 00000000001706f0
[ 6170.287962] Call Trace:
[ 6170.287967] <TASK>
[ 6170.287973] ? __warn+0x9f/0x1a0
[ 6170.287986] ? nf_tables_chain_destroy+0x1f7/0x220 [nf_tables]
[ 6170.288092] ? report_bug+0x1b1/0x1e0
[ 6170.287986] ? nf_tables_chain_destroy+0x1f7/0x220 [nf_tables]
[ 6170.288092] ? report_bug+0x1b1/0x1e0
[ 6170.288104] ? handle_bug+0x3c/0x70
[ 6170.288112] ? exc_invalid_op+0x17/0x40
[ 6170.288120] ? asm_exc_invalid_op+0x1a/0x20
[ 6170.288132] ? nf_tables_chain_destroy+0x2b/0x220 [nf_tables]
[ 6170.288243] ? nf_tables_chain_destroy+0x1f7/0x220 [nf_tables]
[ 6170.288366] ? nf_tables_chain_destroy+0x2b/0x220 [nf_tables]
[ 6170.288483] nf_tables_trans_destroy_work+0x588/0x590 [nf_tables]

Fixes: 591054469b3e ("netfilter: nf_tables: revisit chain/object refcounting from elements")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: restore set elements when delete set fails

From abort path, nft_mapelem_activate() needs to restore refcounters to
the original state. Currently, it uses the set->ops->walk() to iterate
over these set elements. The existing set iterator skips inactive
elements in the next generation, this does not work from the abort path
to restore the original state since it has to skip active elements
instead (not inactive ones).

This patch moves the check for inactive elements to the set iterator
callback, then it reverses the logic for the .activate case which
needs to skip active elements.

Toggle next generation bit for elements when delete set command is
invoked and call nft_clear() from .activate (abort) path to restore the
next generation bit.

The splat below shows an object in mappings memleak:

[43929.457523] ------------[ cut here ]------------
[43929.457532] WARNING: CPU: 0 PID: 1139 at include/net/netfilter/nf_tables.h:1237 nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables]
[...]
[43929.458014] RIP: 0010:nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables]
[43929.458076] Code: 83 f8 01 77 ab 49 8d 7c 24 08 e8 37 5e d0 de 49 8b 6c 24 08 48 8d 7d 50 e8 e9 5c d0 de 8b 45 50 8d 50 ff 89 55 50 85 c0 75 86 <0f> 0b eb 82 0f 0b eb b3 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90
[43929.458081] RSP: 0018:ffff888140f9f4b0 EFLAGS: 00010246
[43929.458086] RAX: 0000000000000000 RBX: ffff8881434f5288 RCX: dffffc0000000000
[43929.458090] RDX: 00000000ffffffff RSI: ffffffffa26d28a7 RDI: ffff88810ecc9550
[43929.458093] RBP: ffff88810ecc9500 R08: 0000000000000001 R09: ffffed10281f3e8f
[43929.458096] R10: 0000000000000003 R11: ffff0000ffff0000 R12: ffff8881434f52a0
[43929.458100] R13: ffff888140f9f5f4 R14: ffff888151c7a800 R15: 0000000000000002
[43929.458103] FS: 00007f0c687c4740(0000) GS:ffff888390800000(0000) knlGS:0000000000000000
[43929.458107] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[43929.458111] CR2: 00007f58dbe5b008 CR3: 0000000123602005 CR4: 00000000001706f0
[43929.458114] Call Trace:
[43929.458118] <TASK>
[43929.458121] ? __warn+0x9f/0x1a0
[43929.458127] ? nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables]
[43929.458188] ? report_bug+0x1b1/0x1e0
[43929.458196] ? handle_bug+0x3c/0x70
[43929.458200] ? exc_invalid_op+0x17/0x40
[43929.458211] ? nft_setelem_data_deactivate+0xd7/0xf0 [nf_tables]
[43929.458271] ? nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables]
[43929.458332] nft_mapelem_deactivate+0x24/0x30 [nf_tables]
[43929.458392] nft_rhash_walk+0xdd/0x180 [nf_tables]
[43929.458453] ? __pfx_nft_rhash_walk+0x10/0x10 [nf_tables]
[43929.458512] ? rb_insert_color+0x2e/0x280
[43929.458520] nft_map_deactivate+0xdc/0x1e0 [nf_tables]
[43929.458582] ? __pfx_nft_map_deactivate+0x10/0x10 [nf_tables]
[43929.458642] ? __pfx_nft_mapelem_deactivate+0x10/0x10 [nf_tables]
[43929.458701] ? __rcu_read_unlock+0x46/0x70
[43929.458709] nft_delset+0xff/0x110 [nf_tables]
[43929.458769] nft_flush_table+0x16f/0x460 [nf_tables]
[43929.458830] nf_tables_deltable+0x501/0x580 [nf_tables]

Fixes: 628bd3e49cba ("netfilter: nf_tables: drop map element references from preparation phase")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_set_pipapo: walk over current view on netlink dump

The generation mask can be updated while netlink dump is in progress.
The pipapo set backend walk iterator cannot rely on it to infer what
view of the datastructure is to be used. Add notation to specify if user
wants to read/update the set.

Based on patch from Florian Westphal.

Fixes: 2b84e215f874 ("netfilter: nft_set_pipapo: .walk does not deal with generations")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Fix potential data-race in __nft_obj_type_get()

nft_unregister_obj() can concurrent with __nft_obj_type_get(),
and there is not any protection when iterate over nf_tables_objects
list in __nft_obj_type_get(). Therefore, there is potential data-race
of nf_tables_objects list entry.

Use list_for_each_entry_rcu() to iterate over nf_tables_objects
list in __nft_obj_type_get(), and use rcu_read_lock() in the caller
nft_obj_type_get() to protect the entire type query process.

Fixes: e50092404c1b ("netfilter: nf_tables: add stateful objects")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Fix potential data-race in __nft_expr_type_get()

nft_unregister_expr() can concurrent with __nft_expr_type_get(),
and there is not any protection when iterate over nf_tables_expressions
list in __nft_expr_type_get(). Therefore, there is potential data-race
of nf_tables_expressions list entry.

Use list_for_each_entry_rcu() to iterate over nf_tables_expressions
list in __nft_expr_type_get(), and use rcu_read_lock() in the caller
nft_expr_type_get() to protect the entire type query process.

Fixes: ef1f7df9170d ("netfilter: nf_tables: expression ops overloading")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: discard table flag update with pending basechain deletion

Hook unregistration is deferred to the commit phase, same occurs with
hook updates triggered by the table dormant flag. When both commands are
combined, this results in deleting a basechain while leaving its hook
still registered in the core.

Fixes: 179d9ba5559a ("netfilter: nf_tables: fix table flag updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Fix potential data-race in __nft_flowtable_type_get()

nft_unregister_flowtable_type() within nf_flow_inet_module_exit() can
concurrent with __nft_flowtable_type_get() within nf_tables_newflowtable().
And thhere is not any protection when iterate over nf_tables_flowtables
list in __nft_flowtable_type_get(). Therefore, there is pertential
data-race of nf_tables_flowtables list entry.

Use list_for_each_entry_rcu() to iterate over nf_tables_flowtables list
in __nft_flowtable_type_get(), and use rcu_read_lock() in the caller
nft_flowtable_type_get() to protect the entire type query process.

Fixes: 3b49e2e94e6e ("netfilter: nf_tables: add flow table netlink frontend")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject new basechain after table flag update

When dormant flag is toggled, hooks are disabled in the commit phase by
iterating over current chains in table (existing and new).

The following configuration allows for an inconsistent state:

add table x
add chain x y { type filter hook input priority 0; }
add table x { flags dormant; }
add chain x w { type filter hook input priority 1; }

which triggers the following warning when trying to unregister chain w
which is already unregistered.

[ 127.322252] WARNING: CPU: 7 PID: 1211 at net/netfilter/core.c:50 1 __nf_unregister_net_hook+0x21a/0x260
[...]
[ 127.322519] Call Trace:
[ 127.322521] <TASK>
[ 127.322524] ? __warn+0x9f/0x1a0
[ 127.322531] ? __nf_unregister_net_hook+0x21a/0x260
[ 127.322537] ? report_bug+0x1b1/0x1e0
[ 127.322545] ? handle_bug+0x3c/0x70
[ 127.322552] ? exc_invalid_op+0x17/0x40
[ 127.322556] ? asm_exc_invalid_op+0x1a/0x20
[ 127.322563] ? kasan_save_free_info+0x3b/0x60
[ 127.322570] ? __nf_unregister_net_hook+0x6a/0x260
[ 127.322577] ? __nf_unregister_net_hook+0x21a/0x260
[ 127.322583] ? __nf_unregister_net_hook+0x6a/0x260
[ 127.322590] ? __nf_tables_unregister_hook+0x8a/0xe0 [nf_tables]
[ 127.322655] nft_table_disable+0x75/0xf0 [nf_tables]
[ 127.322717] nf_tables_commit+0x2571/0x2620 [nf_tables]

Fixes: 179d9ba5559a ("netfilter: nf_tables: fix table flag updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: flush pending destroy work before exit_net release

Similar to 2c9f0293280e ("netfilter: nf_tables: flush pending destroy
work before netlink notifier") to address a race between exit_net and
the destroy workqueue.

The trace below shows an element to be released via destroy workqueue
while exit_net path (triggered via module removal) has already released
the set that is used in such transaction.

[ 1360.547789] BUG: KASAN: slab-use-after-free in nf_tables_trans_destroy_work+0x3f5/0x590 [nf_tables]
[ 1360.547861] Read of size 8 at addr ffff888140500cc0 by task kworker/4:1/152465
[ 1360.547870] CPU: 4 PID: 152465 Comm: kworker/4:1 Not tainted 6.8.0+ #359
[ 1360.547882] Workqueue: events nf_tables_trans_destroy_work [nf_tables]
[ 1360.547984] Call Trace:
[ 1360.547991] <TASK>
[ 1360.547998] dump_stack_lvl+0x53/0x70
[ 1360.548014] print_report+0xc4/0x610
[ 1360.548026] ? __virt_addr_valid+0xba/0x160
[ 1360.548040] ? __pfx__raw_spin_lock_irqsave+0x10/0x10
[ 1360.548054] ? nf_tables_trans_destroy_work+0x3f5/0x590 [nf_tables]
[ 1360.548176] kasan_report+0xae/0xe0
[ 1360.548189] ? nf_tables_trans_destroy_work+0x3f5/0x590 [nf_tables]
[ 1360.548312] nf_tables_trans_destroy_work+0x3f5/0x590 [nf_tables]
[ 1360.548447] ? __pfx_nf_tables_trans_destroy_work+0x10/0x10 [nf_tables]
[ 1360.548577] ? _raw_spin_unlock_irq+0x18/0x30
[ 1360.548591] process_one_work+0x2f1/0x670
[ 1360.548610] worker_thread+0x4d3/0x760
[ 1360.548627] ? __pfx_worker_thread+0x10/0x10
[ 1360.548640] kthread+0x16b/0x1b0
[ 1360.548653] ? __pfx_kthread+0x10/0x10
[ 1360.548665] ret_from_fork+0x2f/0x50
[ 1360.548679] ? __pfx_kthread+0x10/0x10
[ 1360.548690] ret_from_fork_asm+0x1a/0x30
[ 1360.548707] </TASK>

[ 1360.548719] Allocated by task 192061:
[ 1360.548726] kasan_save_stack+0x20/0x40
[ 1360.548739] kasan_save_track+0x14/0x30
[ 1360.548750] __kasan_kmalloc+0x8f/0xa0
[ 1360.548760] __kmalloc_node+0x1f1/0x450
[ 1360.548771] nf_tables_newset+0x10c7/0x1b50 [nf_tables]
[ 1360.548883] nfnetlink_rcv_batch+0xbc4/0xdc0 [nfnetlink]
[ 1360.548909] nfnetlink_rcv+0x1a8/0x1e0 [nfnetlink]
[ 1360.548927] netlink_unicast+0x367/0x4f0
[ 1360.548935] netlink_sendmsg+0x34b/0x610
[ 1360.548944] ____sys_sendmsg+0x4d4/0x510
[ 1360.548953] ___sys_sendmsg+0xc9/0x120
[ 1360.548961] __sys_sendmsg+0xbe/0x140
[ 1360.548971] do_syscall_64+0x55/0x120
[ 1360.548982] entry_SYSCALL_64_after_hwframe+0x55/0x5d

[ 1360.548994] Freed by task 192222:
[ 1360.548999] kasan_save_stack+0x20/0x40
[ 1360.549009] kasan_save_track+0x14/0x30
[ 1360.549019] kasan_save_free_info+0x3b/0x60
[ 1360.549028] poison_slab_object+0x100/0x180
[ 1360.549036] __kasan_slab_free+0x14/0x30
[ 1360.549042] kfree+0xb6/0x260
[ 1360.549049] __nft_release_table+0x473/0x6a0 [nf_tables]
[ 1360.549131] nf_tables_exit_net+0x170/0x240 [nf_tables]
[ 1360.549221] ops_exit_list+0x50/0xa0
[ 1360.549229] free_exit_list+0x101/0x140
[ 1360.549236] unregister_pernet_operations+0x107/0x160
[ 1360.549245] unregister_pernet_subsys+0x1c/0x30
[ 1360.549254] nf_tables_module_exit+0x43/0x80 [nf_tables]
[ 1360.549345] __do_sys_delete_module+0x253/0x370
[ 1360.549352] do_syscall_64+0x55/0x120
[ 1360.549360] entry_SYSCALL_64_after_hwframe+0x55/0x5d

(gdb) list *__nft_release_table+0x473
0x1e033 is in __nft_release_table (net/netfilter/nf_tables_api.c:11354).
11349 list_for_each_entry_safe(flowtable, nf, &table->flowtables, list) {
11350 list_del(&flowtable->list);
11351 nft_use_dec(&table->use);
11352 nf_tables_flowtable_destroy(flowtable);
11353 }
11354 list_for_each_entry_safe(set, ns, &table->sets, list) {
11355 list_del(&set->list);
11356 nft_use_dec(&table->use);
11357 if (set->flags & (NFT_SET_MAP | NFT_SET_OBJECT))
11358 nft_map_deactivate(&ctx, set);
(gdb)

[ 1360.549372] Last potentially related work creation:
[ 1360.549376] kasan_save_stack+0x20/0x40
[ 1360.549384] __kasan_record_aux_stack+0x9b/0xb0
[ 1360.549392] __queue_work+0x3fb/0x780
[ 1360.549399] queue_work_on+0x4f/0x60
[ 1360.549407] nft_rhash_remove+0x33b/0x340 [nf_tables]
[ 1360.549516] nf_tables_commit+0x1c6a/0x2620 [nf_tables]
[ 1360.549625] nfnetlink_rcv_batch+0x728/0xdc0 [nfnetlink]
[ 1360.549647] nfnetlink_rcv+0x1a8/0x1e0 [nfnetlink]
[ 1360.549671] netlink_unicast+0x367/0x4f0
[ 1360.549680] netlink_sendmsg+0x34b/0x610
[ 1360.549690] ____sys_sendmsg+0x4d4/0x510
[ 1360.549697] ___sys_sendmsg+0xc9/0x120
[ 1360.549706] __sys_sendmsg+0xbe/0x140
[ 1360.549715] do_syscall_64+0x55/0x120
[ 1360.549725] entry_SYSCALL_64_after_hwframe+0x55/0x5d

Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: release mutex after nft_gc_seq_end from abort path

The commit mutex should not be released during the critical section
between nft_gc_seq_begin() and nft_gc_seq_end(), otherwise, async GC
worker could collect expired objects and get the released commit lock
within the same GC sequence.

nf_tables_module_autoload() temporarily releases the mutex to load
module dependencies, then it goes back to replay the transaction again.
Move it at the end of the abort phase after nft_gc_seq_end() is called.

Cc: stable@vger.kernel.org
Fixes: 720344340fb9 ("netfilter: nf_tables: GC transaction race with abort path")
Reported-by: Kuan-Ting Chen <hexrabbit@devco.re>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: release batch on table validation from abort path

Unlike early commit path stage which triggers a call to abort, an
explicit release of the batch is required on abort, otherwise mutex is
released and commit_list remains in place.

Add WARN_ON_ONCE to ensure commit_list is empty from the abort path
before releasing the mutex.

After this patch, commit_list is always assumed to be empty before
grabbing the mutex, therefore

03c1f1ef1584 ("netfilter: Cleanup nft_net->module_list from nf_tables_exit_net()")

only needs to release the pending modules for registration.

Cc: stable@vger.kernel.org
Fixes: c0391b6ab810 ("netfilter: nf_tables: missing validation from the abort path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: skip netdev hook unregistration if table is dormant

Skip hook unregistration when adding or deleting devices from an
existing netdev basechain. Otherwise, commit/abort path try to
unregister hooks which not enabled.

Fixes: b9703ed44ffb ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Fixes: 7d937b107108 ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject table flag and netdev basechain updates

netdev basechain updates are stored in the transaction object hook list.
When setting on the table dormant flag, it iterates over the existing
hooks in the basechain. Thus, skipping the hooks that are being
added/deleted in this transaction, which leaves hook registration in
inconsistent state.

Reject table flag updates in combination with netdev basechain updates
in the same batch:

- Update table flags and add/delete basechain: Check from basechain update
path if there are pending flag updates for this table.
- add/delete basechain and update table flags: Iterate over the transaction
list to search for basechain updates from the table update path.

In both cases, the batch is rejected. Based on suggestion from Florian Westphal.

Fixes: b9703ed44ffb ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Fixes: 7d937b107108f ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject destroy command to remove basechain hooks

Report EOPNOTSUPP if NFT_MSG_DESTROYCHAIN is used to delete hooks in an
existing netdev basechain, thus, only NFT_MSG_DELCHAIN is allowed.

Fixes: 7d937b107108f ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Fix a memory leak in nf_tables_updchain

If nft_netdev_register_hooks() fails, the memory associated with
nft_stats is not freed, causing a memory leak.

This patch fixes it by moving nft_stats_alloc() down after
nft_netdev_register_hooks() succeeds.

Fixes: b9703ed44ffb ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Signed-off-by: Quan Tian <tianquan23@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not compare internal table flags on updates

Restore skipping transaction if table update does not modify flags.

Fixes: 179d9ba5559a ("netfilter: nf_tables: fix table flag updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: pass flags to set backend selection routine

No need to refetch the flag from the netlink attribute, pass the
existing flags variable which already provide validated flags.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Implement table adoption support

Allow a new process to take ownership of a previously owned table,
useful mostly for firewall management services restarting or suspending
when idle.

By extending __NFT_TABLE_F_UPDATE, the on/off/on check in
nf_tables_updtable() also covers table adoption, although it is actually
not needed: Table adoption is irreversible because nf_tables_updtable()
rejects attempts to drop NFT_TABLE_F_OWNER so table->nlpid setting can
happen just once within the transaction.

If the transaction commences, table's nlpid and flags fields are already
set and no further action is required. If it aborts, the table returns
to orphaned state.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Introduce NFT_TABLE_F_PERSIST

This companion flag to NFT_TABLE_F_OWNER requests the kernel to keep the
table around after the process has exited. It marks such table as
orphaned (by dropping OWNER flag but keeping PERSIST flag in place),
which opens it for other processes to manipulate. For the sake of
simplicity, PERSIST flag may not be altered though.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: mark set as dead when unbinding anonymous set with timeout

While the rhashtable set gc runs asynchronously, a race allows it to
collect elements from anonymous sets with timeouts while it is being
released from the commit path.

Mingi Cho originally reported this issue in a different path in 6.1.x
with a pipapo set with low timeouts which is not possible upstream since
7395dfacfff6 ("netfilter: nf_tables: use timestamp to check for set
element timeout").

Fix this by setting on the dead flag for anonymous sets to skip async gc
in this case.

According to 08e4c8c5919f ("netfilter: nf_tables: mark newset as dead on
transaction abort"), Florian plans to accelerate abort path by releasing
objects via workqueue, therefore, this sets on the dead flag for abort
path too.

Cc: stable@vger.kernel.org
Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Reported-by: Mingi Cho <mgcho.minic@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject constant set with timeout

This set combination is weird: it allows for elements to be
added/deleted, but once bound to the rule it cannot be updated anymore.
Eventually, all elements expire, leading to an empty set which cannot
be updated anymore. Reject this flags combination.

Cc: stable@vger.kernel.org
Fixes: 761da2935d6e ("netfilter: nf_tables: add set timeout API support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow anonymous set with timeout flag

Anonymous sets are never used with timeout from userspace, reject this.
Exception to this rule is NFT_SET_EVAL to ensure legacy meters still work.

Cc: stable@vger.kernel.org
Fixes: 761da2935d6e ("netfilter: nf_tables: add set timeout API support")
Reported-by: lonial con <kongln9170@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: use kzalloc for hook allocation

KMSAN reports unitialized variable when registering the hook,
reg->hook_ops_type == NF_HOOK_OP_BPF)
~~~~~~~~~~~ undefined

This is a small structure, just use kzalloc to make sure this
won't happen again when new fields get added to nf_hook_ops.

Fixes: 7b4b2fa37587 ("netfilter: annotate nf_tables base hook ops")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: register hooks last when adding new chain/flowtable

Register hooks last when adding chain/flowtable to ensure that packets do
not walk over datastructure that is being released in the error path
without waiting for the rcu grace period.

Fixes: 91c7b38dc9f0 ("netfilter: nf_tables: use new transaction infrastructure to handle chain")
Fixes: 3b49e2e94e6e ("netfilter: nf_tables: add flow table netlink frontend")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: set dormant flag on hook register failure

We need to set the dormant flag again if we fail to register
the hooks.

During memory pressure hook registration can fail and we end up
with a table marked as active but no registered hooks.

On table/base chain deletion, nf_tables will attempt to unregister
the hook again which yields a warn splat from the nftables core.

Reported-and-tested-by: syzbot+de4025c006ec68ac56fc@syzkaller.appspotmail.com
Fixes: 179d9ba5559a ("netfilter: nf_tables: fix table flag updates")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: use timestamp to check for set element timeout

Add a timestamp field at the beginning of the transaction, store it
in the nftables per-netns area.

Update set backend .insert, .deactivate and sync gc path to use the
timestamp, this avoids that an element expires while control plane
transaction is still unfinished.

.lookup and .update, which are used from packet path, still use the
current time to check if the element has expired. And .get path and dump
also since this runs lockless under rcu read size lock. Then, there is
async gc which also needs to check the current time since it runs
asynchronously from a workqueue.

Fixes: c3e1b005ed1c ("netfilter: nf_tables: add set element timeout support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: restrict tunnel object to NFPROTO_NETDEV

Bail out on using the tunnel dst template from other than netdev family.
Add the infrastructure to check for the family in objects.

Fixes: af308b94a2a4 ("netfilter: nf_tables: add tunnel support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject QUEUE/DROP verdict parameters

This reverts commit e0abdadcc6e1.

core.c:nf_hook_slow assumes that the upper 16 bits of NF_DROP
verdicts contain a valid errno, i.e. -EPERM, -EHOSTUNREACH or similar,
or 0.

Due to the reverted commit, its possible to provide a positive
value, e.g. NF_ACCEPT (1), which results in use-after-free.

Its not clear to me why this commit was made.

NF_QUEUE is not used by nftables; "queue" rules in nftables
will result in use of "nft_queue" expression.

If we later need to allow specifiying errno values from userspace
(do not know why), this has to call NF_DROP_GETERR and check that
"err <= 0" holds true.

Fixes: e0abdadcc6e1 ("netfilter: nf_tables: accept QUEUE/DROP verdict parameters")
Cc: stable@vger.kernel.org
Reported-by: Notselwyn <notselwyn@pwning.tech>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: restrict anonymous set and map names to 16 bytes

nftables has two types of sets/maps, one where userspace defines the
name, and anonymous sets/maps, where userspace defines a template name.

For the latter, kernel requires presence of exactly one "%d".
nftables uses "__set%d" and "__map%d" for this. The kernel will
expand the format specifier and replaces it with the smallest unused
number.

As-is, userspace could define a template name that allows to move
the set name past the 256 bytes upperlimit (post-expansion).

I don't see how this could be a problem, but I would prefer if userspace
cannot do this, so add a limit of 16 bytes for the '%d' template name.

16 bytes is the old total upper limit for set names that existed when
nf_tables was merged initially.

Fixes: 387454901bd6 ("netfilter: nf_tables: Allow set names of up to 255 chars")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject NFT_SET_CONCAT with not field length description

It is still possible to set on the NFT_SET_CONCAT flag by specifying a
set size and no field description, report EINVAL in such case.

Fixes: 1b6345d4160e ("netfilter: nf_tables: check NFT_SET_CONCAT flag if field_count is specified")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: skip dead set elements in netlink dump

Delete from packet path relies on the garbage collector to purge
elements with NFT_SET_ELEM_DEAD_BIT on.

Skip these dead elements from nf_tables_dump_setelem() path, I very
rarely see tests/shell/testcases/maps/typeof_maps_add_delete reports
[DUMP FAILED] showing a mismatch in the expected output with an element
that should not be there.

If the netlink dump happens before GC worker run, it might show dead
elements in the ruleset listing.

nft_rhash_get() already skips dead elements in nft_rhash_cmp(),
therefore, it already does not show the element when getting a single
element via netlink control plane.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not allow mismatch field size and set key length

The set description provides the size of each field in the set whose sum
should not mismatch the set key length, bail out otherwise.

I did not manage to crash nft_set_pipapo with mismatch fields and set key
length so far, but this is UB which must be disallowed.

Fixes: f3a2181e16f1 ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: check if catch-all set element is active in next generation

When deactivating the catch-all set element, check the state in the next
generation that represents this transaction.

This bug uncovered after the recent removal of the element busy mark
a2dd0233cbc4 ("netfilter: nf_tables: remove busy mark and gc batch API").

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Cc: stable@vger.kernel.org
Reported-by: lonial con <kongln9170@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: bail out if stateful expression provides no .clone

All existing NFT_EXPR_STATEFUL provide a .clone interface, remove
fallback to copy content of stateful expression since this is never
exercised and bail out if .clone interface is not defined.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: validate .maxattr at expression registration

struct nft_expr_info allows to store up to NFT_EXPR_MAXATTR (16)
attributes when parsing netlink attributes.

Rise a warning in case there is ever a nft expression whose .maxattr
goes beyond this number of expressions, in such case, struct nft_expr_info
needs to be updated.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject invalid set policy

Report -EINVAL in case userspace provides a unsupported set backend
policy.

Fixes: c50b960ccc59 ("netfilter: nf_tables: implement proper set selection")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: validate chain type update if available

Parse netlink attribute containing the chain type in this update, to
bail out if this is different from the existing type.

Otherwise, it is possible to define a chain with the same name, hook and
priority but different type, which is silently ignored.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: mark newset as dead on transaction abort

If a transaction is aborted, we should mark the to-be-released NEWSET dead,
just like commit path does for DEL and DESTROYSET commands.

In both cases all remaining elements will be released via
set->ops->destroy().

The existing abort code does NOT post the actual release to the work queue.
Also the entire __nf_tables_abort() function is wrapped in gc_seq
begin/end pair.

Therefore, async gc worker will never try to release the pending set
elements, as gc sequence is always stale.

It might be possible to speed up transaction aborts via work queue too,
this would result in a race and a possible use-after-free.

So fix this before it becomes an issue.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Add locking for NFT_MSG_GETSETELEM_RESET requests

Set expressions' dump callbacks are not concurrency-safe per-se with
reset bit set. If two CPUs reset the same element at the same time,
values may underrun at least with element-attached counters and quotas.

Prevent this by introducing dedicated callbacks for nfnetlink and the
asynchronous dump handling to serialize access.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Introduce nft_set_dump_ctx_init()

This is a wrapper around nft_ctx_init() for use in
nf_tables_getsetelem() and a resetting equivalent introduced later.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Pass const set to nft_get_set_elem

The function is not supposed to alter the set, passing the pointer as
const is fine and merely requires to adjust signatures of two called
functions as well.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: skip set commit for deleted/destroyed sets

NFT_MSG_DELSET deactivates all elements in the set, skip
set->ops->commit() to avoid the unnecessary clone (for the pipapo case)
as well as the sync GC cycle, which could deactivate again expired
elements in such set.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Reported-by: Kevin Rich <kevinrich1337@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: validate family when identifying table via handle

Validate table family when looking up for it via NFTA_TABLE_HANDLE.

Fixes: 3ecbfd65f50e ("netfilter: nf_tables: allocate handle and delete objects via handle")
Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: split async and sync catchall in two functions

list_for_each_entry_safe() does not work for the async case which runs
under RCU, therefore, split GC logic for catchall in two functions
instead, one for each of the sync and async GC variants.

The catchall sync GC variant never sees a _DEAD bit set on ever, thus,
this handling is removed in such case, moreover, allocate GC sync batch
via GFP_KERNEL.

Fixes: 93995bf4af2c ("netfilter: nf_tables: remove catchall element in GC sync path")
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: bogus ENOENT when destroying element which does not exist

destroy element command bogusly reports ENOENT in case a set element
does not exist. ENOENT errors are skipped, however, err is still set
and propagated to userspace.

# nft destroy element ip raw BLACKLIST { 1.2.3.4 }
Error: Could not process rule: No such file or directory
destroy element ip raw BLACKLIST { 1.2.3.4 }
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Fixes: f80a612dd77c ("netfilter: nf_tables: add support to destroy operation")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: remove catchall element in GC sync path

The expired catchall element is not deactivated and removed from GC sync
path. This path holds mutex so just call nft_setelem_data_deactivate()
and nft_setelem_catchall_remove() before queueing the GC work.

Fixes: 4a9e12ea7e70 ("netfilter: nft_set_pipapo: call nft_trans_gc_queue_sync() in catchall GC")
Reported-by: lonial con <kongln9170@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add missing module descriptions

W=1 builds warn on missing MODULE_DESCRIPTION, add them.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Carry reset boolean in nft_set_dump_ctx

Relieve the dump callback from having to check nlmsg_type upon each
call. Prep work for set element reset locking.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: set->ops->insert returns opaque set element in case of EEXIST

Return struct nft_elem_priv instead of struct nft_set_ext for
consistency with ("netfilter: nf_tables: expose opaque set element as
struct nft_elem_priv") and to prepare the introduction of element
timeout updates from control path.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: shrink memory consumption of set elements

Instead of copying struct nft_set_elem into struct nft_trans_elem, store
the pointer to the opaque set element object in the transaction. Adapt
set backend API (and set backend implementations) to take the pointer to
opaque set element representation whenever required.

This patch deconstifies .remove() and .activate() set backend API since
these modify the set element opaque object. And it also constify
nft_set_elem_ext() this provides access to the nft_set_ext struct
without updating the object.

According to pahole on x86_64, this patch shrinks struct nft_trans_elem
size from 216 to 24 bytes.

This patch also reduces stack memory consumption by removing the
template struct nft_set_elem object, using the opaque set element object
instead such as from the set iterator API, catchall elements and the get
element command.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: expose opaque set element as struct nft_elem_priv

Add placeholder structure and place it at the beginning of each struct
nft_*_elem for each existing set backend, instead of exposing elements
as void type to the frontend which defeats compiler type checks. Use
this pointer to this new type to replace void *.

This patch updates the following set backend API to use this new struct
nft_elem_priv placeholder structure:

- update
- deactivate
- flush
- get

as well as the following helper functions:

- nft_set_elem_ext()
- nft_set_elem_init()
- nft_set_elem_destroy()
- nf_tables_set_elem_destroy()

This patch adds nft_elem_priv_cast() to cast struct nft_elem_priv to
native element representation from the corresponding set backend.
BUILD_BUG_ON() makes sure this .priv placeholder is always at the top
of the opaque set element representation.

Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: set backend .flush always succeeds

.flush is always successful since this results from iterating over the
set elements to toggle mark the element as inactive in the next
generation.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Carry reset boolean in nft_obj_dump_ctx

Relieve the dump callback from having to inspect nlmsg_type upon each
call, just do it once at start of the dump.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: nft_obj_filter fits into cb->ctx

No need to allocate it if one may just use struct netlink_callback's
scratch area for it.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Carry s_idx in nft_obj_dump_ctx

Prep work for moving the context into struct netlink_callback scratch
area.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: A better name for nft_obj_filter

Name it for what it is supposed to become, a real nft_obj_dump_ctx. No
functional change intended.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Unconditionally allocate nft_obj_filter

Prep work for moving the filter into struct netlink_callback's scratch
area.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Drop pointless memset in nf_tables_dump_obj

The code does not make use of cb->args fields past the first one, no
need to zero them.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Add locking for NFT_MSG_GETRULE_RESET requests

Rule reset is not concurrency-safe per-se, so multiple CPUs may reset
the same rule at the same time. At least counter and quota expressions
will suffer from value underruns in this case.

Prevent this by introducing dedicated locking callbacks for nfnetlink
and the asynchronous dump handling to serialize access.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Introduce nf_tables_getrule_single()

Outsource the reply skb preparation for non-dump getrule requests into a
distinct function. Prep work for rule reset locking.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Open-code audit log call in nf_tables_getrule()

The table lookup will be dropped from that function, so remove that
dependency from audit logging code. Using whatever is in
nla[NFTA_RULE_TABLE] is sufficient as long as the previous rule info
filling succeded.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Don't allocate nft_rule_dump_ctx

Since struct netlink_callback::args is not used by rule dumpers anymore,
use it to hold nft_rule_dump_ctx. Add a build-time check to make sure it
won't ever exceed the available space.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Carry s_idx in nft_rule_dump_ctx

In order to move the context into struct netlink_callback's scratch
area, the latter must be unused first.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Carry reset flag in nft_rule_dump_ctx

This relieves the dump callback from having to check nlmsg_type upon
each call and instead performs the check once in .start callback.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Drop pointless memset when dumping rules

None of the dump callbacks uses netlink_callback::args beyond the first
element, no need to zero the data.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Always allocate nft_rule_dump_ctx

It will move into struct netlink_callback's scratch area later, just put
nf_tables_dump_rules_start in shape to reduce churn later.

Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Utilize NLA_POLICY_NESTED_ARRAY

Mark attributes which are supposed to be arrays of nested attributes
with known content as such. Originally suggested for
NFTA_RULE_EXPRESSIONS only, but does apply to others as well.

Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: missing extended netlink error in lookup functions

Set netlink extended error reporting for several lookup functions which
allows userspace to infer what is the error cause.

Reported-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: revert do not remove elements if set backend implements .abort

nf_tables_abort_release() path calls nft_set_elem_destroy() for
NFT_MSG_NEWSETELEM which releases the element, however, a reference to
the element still remains in the working copy.

Fixes: ebd032fa8818 ("netfilter: nf_tables: do not remove elements if set backend implements .abort")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: audit log object reset once per table

When resetting multiple objects at once (via dump request), emit a log
message per table (or filled skb) and resurrect the 'entries' parameter
to contain the number of objects being logged for.

To test the skb exhaustion path, perform some bulk counter and quota
adds in the kselftest.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com> (Audit)
Signed-off-by: Florian Westphal <fw@strlen.de>

nf_tables: fix NULL pointer dereference in nft_expr_inner_parse()

We should check whether the NFTA_EXPR_NAME netlink attribute is present
before accessing it, otherwise a null pointer deference error will occur.

Call Trace:
<TASK>
dump_stack_lvl+0x4f/0x90
print_report+0x3f0/0x620
kasan_report+0xcd/0x110
__asan_load2+0x7d/0xa0
nla_strcmp+0x2f/0x90
__nft_expr_type_get+0x41/0xb0
nft_expr_inner_parse+0xe3/0x200
nft_inner_init+0x1be/0x2e0
nf_tables_newrule+0x813/0x1230
nfnetlink_rcv_batch+0xec3/0x1170
nfnetlink_rcv+0x1e4/0x220
netlink_unicast+0x34e/0x4b0
netlink_sendmsg+0x45c/0x7e0
__sys_sendto+0x355/0x370
__x64_sys_sendto+0x84/0xa0
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Fixes: 3a07327d10a0 ("netfilter: nft_inner: support for inner tunnel header matching")
Signed-off-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: do not refresh timeout when resetting element

The dump and reset command should not refresh the timeout, this command
is intended to allow users to list existing stateful objects and reset
them, element expiration should be refresh via transaction instead with
a specific command to achieve this, otherwise this is entering combo
semantics that will be hard to be undone later (eg. a user asking to
retrieve counters but _not_ requiring to refresh expiration).

Fixes: 079cd633219d ("netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: do not remove elements if set backend implements .abort

pipapo set backend maintains two copies of the datastructure, removing
the elements from the copy that is going to be discarded slows down
the abort path significantly, from several minutes to few seconds after
this patch.

Fixes: 212ed75dc5fb ("netfilter: nf_tables: integrate pipapo into commit protocol")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Deduplicate nft_register_obj audit logs

When adding/updating an object, the transaction handler emits suitable
audit log entries already, the one in nft_obj_notify() is redundant. To
fix that (and retain the audit logging from objects' 'update' callback),
Introduce an "audit log free" variant for internal use.

Fixes: c520292f29b8 ("audit: log nftables configuration change events once per table")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com> (Audit)
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: fix memleak when more than 255 elements expired

When more than 255 elements expired we're supposed to switch to a new gc
container structure.

This never happens: u8 type will wrap before reaching the boundary
and nft_trans_gc_space() always returns true.

This means we recycle the initial gc container structure and
lose track of the elements that came before.

While at it, don't deref 'gc' after we've passed it to call_rcu.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Reported-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: disable toggling dormant table state more than once

nft -f -<<EOF
add table ip t
add table ip t { flags dormant; }
add chain ip t c { type filter hook input priority 0; }
add table ip t
EOF

Triggers a splat from nf core on next table delete because we lose
track of right hook register state:

WARNING: CPU: 2 PID: 1597 at net/netfilter/core.c:501 __nf_unregister_net_hook
RIP: 0010:__nf_unregister_net_hook+0x41b/0x570
nf_unregister_net_hook+0xb4/0xf0
__nf_tables_unregister_hook+0x160/0x1d0
[..]

The above should have table in *active* state, but in fact no
hooks were registered.

Reject on/off/on games rather than attempting to fix this.

Fixes: 179d9ba5559a ("netfilter: nf_tables: fix table flag updates")
Reported-by: "Lee, Cherie-Anne" <cherie.lee@starlabs.sg>
Cc: Bing-Jhong Billy Jheng <billy@starlabs.sg>
Cc: info@starlabs.sg
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Fix entries val in rule reset audit log

The value in idx and the number of rules handled in that particular
__nf_tables_dump_rules() call is not identical. The former is a cursor
to pick up from if multiple netlink messages are needed, so its value is
ever increasing. Fixing this is not just a matter of subtracting s_idx
from it, though: When resetting rules in multiple chains,
__nf_tables_dump_rules() is called for each and cb->args[0] is not
adjusted in between. Introduce a dedicated counter to record the number
of rules reset in this call in a less confusing way.

While being at it, prevent the direct return upon buffer exhaustion: Any
rules previously dumped into that skb would evade audit logging
otherwise.

Fixes: 9b5ba5c9c5109 ("netfilter: nf_tables: Unbreak audit log reset")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow element removal on anonymous sets

Anonymous sets need to be populated once at creation and then they are
bound to rule since 938154b93be8 ("netfilter: nf_tables: reject unbound
anonymous set before commit phase"), otherwise transaction reports
EINVAL.

Userspace does not need to delete elements of anonymous sets that are
not yet bound, reject this with EOPNOTSUPP.

From flush command path, skip anonymous sets, they are expected to be
bound already. Otherwise, EINVAL is hit at the end of this transaction
for unbound sets.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_set_pipapo: call nft_trans_gc_queue_sync() in catchall GC

pipapo needs to enqueue GC transactions for catchall elements through
nft_trans_gc_queue_sync(). Add nft_trans_gc_catchall_sync() and
nft_trans_gc_catchall_async() to handle GC transaction queueing
accordingly.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Fixes: f6c383b8c31a ("netfilter: nf_tables: adapt set backend to use GC transaction API")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow rule removal from chain binding

Chain binding only requires the rule addition/insertion command within
the same transaction. Removal of rules from chain bindings within the
same transaction makes no sense, userspace does not utilize this
feature. Replace nft_chain_is_bound() check to nft_chain_binding() in
rule deletion commands. Replace command implies a rule deletion, reject
this command too.

Rule flush command can also safely rely on this nft_chain_binding()
check because unbound chains are not allowed since 62e1e94b246e
("netfilter: nf_tables: reject unbound chain set before commit phase").

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Reported-by: Kevin Rich <kevinrich1337@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Unbreak audit log reset

Deliver audit log from __nf_tables_dump_rules(), table dereference at
the end of the table list loop might point to the list head, leading to
this crash.

[ 4137.407349] BUG: unable to handle page fault for address: 00000000001f3c50
[ 4137.407357] #PF: supervisor read access in kernel mode
[ 4137.407359] #PF: error_code(0x0000) - not-present page
[ 4137.407360] PGD 0 P4D 0
[ 4137.407363] Oops: 0000 [#1] PREEMPT SMP PTI
[ 4137.407365] CPU: 4 PID: 500177 Comm: nft Not tainted 6.5.0+ #277
[ 4137.407369] RIP: 0010:string+0x49/0xd0
[ 4137.407374] Code: ff 77 36 45 89 d1 31 f6 49 01 f9 66 45 85 d2 75 19 eb 1e 49 39 f8 76 02 88 07 48 83 c7 01 83 c6 01 48 83 c2 01 4c 39 cf 74 07 <0f> b6 02 84 c0 75 e2 4c 89 c2 e9 58 e5 ff ff 48 c7 c0 0e b2 ff 81
[ 4137.407377] RSP: 0018:ffff8881179737f0 EFLAGS: 00010286
[ 4137.407379] RAX: 00000000001f2c50 RBX: ffff888117973848 RCX: ffff0a00ffffff04
[ 4137.407380] RDX: 00000000001f3c50 RSI: 0000000000000000 RDI: 0000000000000000
[ 4137.407381] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000ffffffff
[ 4137.407383] R10: ffffffffffffffff R11: ffff88813584d200 R12: 0000000000000000
[ 4137.407384] R13: ffffffffa15cf709 R14: 0000000000000000 R15: ffffffffa15cf709
[ 4137.407385] FS: 00007fcfc18bb580(0000) GS:ffff88840e700000(0000) knlGS:0000000000000000
[ 4137.407387] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4137.407388] CR2: 00000000001f3c50 CR3: 00000001055b2001 CR4: 00000000001706e0
[ 4137.407390] Call Trace:
[ 4137.407392] <TASK>
[ 4137.407393] ? __die+0x1b/0x60
[ 4137.407397] ? page_fault_oops+0x6b/0xa0
[ 4137.407399] ? exc_page_fault+0x60/0x120
[ 4137.407403] ? asm_exc_page_fault+0x22/0x30
[ 4137.407408] ? string+0x49/0xd0
[ 4137.407410] vsnprintf+0x257/0x4f0
[ 4137.407414] kvasprintf+0x3e/0xb0
[ 4137.407417] kasprintf+0x3e/0x50
[ 4137.407419] nf_tables_dump_rules+0x1c0/0x360 [nf_tables]
[ 4137.407439] ? __alloc_skb+0xc3/0x170
[ 4137.407442] netlink_dump+0x170/0x330
[ 4137.407447] __netlink_dump_start+0x227/0x300
[ 4137.407449] nf_tables_getrule+0x205/0x390 [nf_tables]

Deliver audit log only once at the end of the rule dump+reset for
consistency with the set dump+reset.

Ensure audit reset access to table under rcu read side lock. The table
list iteration holds rcu read lock side, but recent audit code
dereferences table object out of the rcu read lock side.

Fixes: ea078ae9108e ("netfilter: nf_tables: Audit log rule reset")
Fixes: 7e9be1124dbe ("netfilter: nf_tables: Audit log setelem reset")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: Audit log rule reset

Resetting rules' stateful data happens outside of the transaction logic,
so 'get' and 'dump' handlers have to emit audit log entries themselves.

Fixes: 8daa8fde3fc3f ("netfilter: nf_tables: Introduce NFT_MSG_GETRULE_RESET")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Audit log setelem reset

Since set element reset is not integrated into nf_tables' transaction
logic, an explicit log call is needed, similar to NFT_MSG_GETOBJ_RESET
handling.

For the sake of simplicity, catchall element reset will always generate
a dedicated log entry. This relieves nf_tables_dump_set() from having to
adjust the logged element count depending on whether a catchall element
was found or not.

Fixes: 079cd633219d7 ("netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: allow loop termination for pending fatal signal

abort early so task can exit faster if a fatal signal is pending,
no need to continue validation in that case.

Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: use correct lock to protect gc_list

Use nf_tables_gc_list_lock spinlock, not nf_tables_destroy_list_lock to
protect the gc list.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: GC transaction race with abort path

Abort path is missing a synchronization point with GC transactions. Add
GC sequence number hence any GC transaction losing race will be
discarded.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: flush pending destroy work before netlink notifier

Destroy work waits for the RCU grace period then it releases the objects
with no mutex held. All releases objects follow this path for
transactions, therefore, order is guaranteed and references to top-level
objects in the hierarchy remain valid.

However, netlink notifier might interfer with pending destroy work.
rcu_barrier() is not correct because objects are not release via RCU
callback. Flush destroy work before releasing objects from netlink
notifier path.

Fixes: d4bc8271db21 ("netfilter: nf_tables: netlink notifier might race to release objects")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: validate all pending tables

We have to validate all tables in the transaction that are in
VALIDATE_DO state, the blamed commit below did not move the break
statement to its right location so we only validate one table.

Moreover, we can't init table->validate to _SKIP when a table object
is allocated.

If we do, then if a transcaction creates a new table and then
fails the transaction, nfnetlink will loop and nft will hang until
user cancels the command.

Add back the pernet state as a place to stash the last state encountered.
This is either _DO (we hit an error during commit validation) or _SKIP
(transaction passed all checks).

Fixes: 00c320f9b755 ("netfilter: nf_tables: make validation state per table")
Reported-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: GC transaction race with netns dismantle

Use maybe_get_net() since GC workqueue might race with netns exit path.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: fix GC transaction races with netns and netlink event exit path

Netlink event path is missing a synchronization point with GC
transactions. Add GC sequence number update to netns release path and
netlink event path, any GC transaction losing race will be discarded.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: deactivate catchall elements in next generation

When flushing, individual set elements are disabled in the next
generation via the ->flush callback.

Catchall elements are not disabled. This is incorrect and may lead to
double-deactivations of catchall elements which then results in memory
leaks:

WARNING: CPU: 1 PID: 3300 at include/net/netfilter/nf_tables.h:1172 nft_map_deactivate+0x549/0x730
CPU: 1 PID: 3300 Comm: nft Not tainted 6.5.0-rc5+ #60
RIP: 0010:nft_map_deactivate+0x549/0x730
[..]
? nft_map_deactivate+0x549/0x730
nf_tables_delset+0xb66/0xeb0

(the warn is due to nft_use_dec() detecting underflow).

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Reported-by: lonial con <kongln9170@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: remove busy mark and gc batch API

Ditch it, it has been replace it by the GC transaction API and it has no
clients anymore.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: adapt set backend to use GC transaction API

Use the GC transaction API to replace the old and buggy gc API and the
busy mark approach.

No set elements are removed from async garbage collection anymore,
instead the _DEAD bit is set on so the set element is not visible from
lookup path anymore. Async GC enqueues transaction work that might be
aborted and retried later.

rbtree and pipapo set backends does not set on the _DEAD bit from the
sync GC path since this runs in control plane path where mutex is held.
In this case, set elements are deactivated, removed and then released
via RCU callback, sync GC never fails.

Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Fixes: 8d8540c4f5e0 ("netfilter: nft_set_rbtree: add timeout support")
Fixes: 9d0982927e79 ("netfilter: nft_hash: add support for timeouts")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: GC transaction API to avoid race with control plane

The set types rhashtable and rbtree use a GC worker to reclaim memory.
From system work queue, in periodic intervals, a scan of the table is
done.

The major caveat here is that the nft transaction mutex is not held.
This causes a race between control plane and GC when they attempt to
delete the same element.

We cannot grab the netlink mutex from the work queue, because the
control plane has to wait for the GC work queue in case the set is to be
removed, so we get following deadlock:

cpu 1 cpu2
GC work transaction comes in , lock nft mutex
`acquire nft mutex // BLOCKS
transaction asks to remove the set
set destruction calls cancel_work_sync()

cancel_work_sync will now block forever, because it is waiting for the
mutex the caller already owns.

This patch adds a new API that deals with garbage collection in two
steps:

1) Lockless GC of expired elements sets on the NFT_SET_ELEM_DEAD_BIT
so they are not visible via lookup. Annotate current GC sequence in
the GC transaction. Enqueue GC transaction work as soon as it is
full. If ruleset is updated, then GC transaction is aborted and
retried later.

2) GC work grabs the mutex. If GC sequence has changed then this GC
transaction lost race with control plane, abort it as it contains
stale references to objects and let GC try again later. If the
ruleset is intact, then this GC transaction deactivates and removes
the elements and it uses call_rcu() to destroy elements.

Note that no elements are removed from GC lockless path, the _DEAD bit
is set and pointers are collected. GC catchall does not remove the
elements anymore too. There is a new set->dead flag that is set on to
abort the GC transaction to deal with set->ops->destroy() path which
removes the remaining elements in the set from commit_release, where no
mutex is held.

To deal with GC when mutex is held, which allows safe deactivate and
removal, add sync GC API which releases the set element object via
call_rcu(). This is used by rbtree and pipapo backends which also
perform garbage collection from control plane path.

Since element removal from sets can happen from control plane and
element garbage collection/timeout, it is necessary to keep the set
structure alive until all elements have been deactivated and destroyed.

We cannot do a cancel_work_sync or flush_work in nft_set_destroy because
its called with the transaction mutex held, but the aforementioned async
work queue might be blocked on the very mutex that nft_set_destroy()
callchain is sitting on.

This gives us the choice of ABBA deadlock or UaF.

To avoid both, add set->refs refcount_t member. The GC API can then
increment the set refcount and release it once the elements have been
free'd.

Set backends are adapted to use the GC transaction API in a follow up
patch entitled:

("netfilter: nf_tables: use gc transaction API in set backends")

This is joint work with Florian Westphal.

Fixes: cfed7e1b1f8e ("netfilter: nf_tables: add set garbage collection helpers")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: don't skip expired elements during walk

There is an asymmetry between commit/abort and preparation phase if the
following conditions are met:

1. set is a verdict map ("1.2.3.4 : jump foo")
2. timeouts are enabled

In this case, following sequence is problematic:

1. element E in set S refers to chain C
2. userspace requests removal of set S
3. kernel does a set walk to decrement chain->use count for all elements
from preparation phase
4. kernel does another set walk to remove elements from the commit phase
(or another walk to do a chain->use increment for all elements from
abort phase)

If E has already expired in 1), it will be ignored during list walk, so its use count
won't have been changed.

Then, when set is culled, ->destroy callback will zap the element via
nf_tables_set_elem_destroy(), but this function is only safe for
elements that have been deactivated earlier from the preparation phase:
lack of earlier deactivate removes the element but leaks the chain use
count, which results in a WARN splat when the chain gets removed later,
plus a leak of the nft_chain structure.

Update pipapo_get() not to skip expired elements, otherwise flush
command reports bogus ENOENT errors.

Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Fixes: 8d8540c4f5e0 ("netfilter: nft_set_rbtree: add timeout support")
Fixes: 9d0982927e79 ("netfilter: nft_hash: add support for timeouts")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow rule addition to bound chain via NFTA_RULE_CHAIN_ID

Bail out with EOPNOTSUPP when adding rule to bound chain via
NFTA_RULE_CHAIN_ID. The following warning splat is shown when
adding a rule to a deleted bound chain:

WARNING: CPU: 2 PID: 13692 at net/netfilter/nf_tables_api.c:2013 nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]
CPU: 2 PID: 13692 Comm: chain-bound-rul Not tainted 6.1.39 #1
RIP: 0010:nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Reported-by: Kevin Rich <kevinrich1337@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: skip bound chain on rule flush

Skip bound chain when flushing table rules, the rule that owns this
chain releases these objects.

Otherwise, the following warning is triggered:

WARNING: CPU: 2 PID: 1217 at net/netfilter/nf_tables_api.c:2013 nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]
CPU: 2 PID: 1217 Comm: chain-flush Not tainted 6.1.39 #1
RIP: 0010:nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Reported-by: Kevin Rich <kevinrich1337@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: skip bound chain in netns release path

Skip bound chain from netns release path, the rule that owns this chain
releases these objects.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: can't schedule in nft_chain_validate

Can be called via nft set element list iteration, which may acquire
rcu and/or bh read lock (depends on set type).

BUG: sleeping function called from invalid context at net/netfilter/nf_tables_api.c:3353
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 1232, name: nft
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
2 locks held by nft/1232:
#0: ffff8881180e3ea8 (&nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_valid_genid
#1: ffffffff83f5f540 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire
Call Trace:
nft_chain_validate
nft_lookup_validate_setelem
nft_pipapo_walk
nft_lookup_validate
nft_chain_validate
nft_immediate_validate
nft_chain_validate
nf_tables_validate
nf_tables_abort

No choice but to move it to nf_tables_validate().

Fixes: 81ea01066741 ("netfilter: nf_tables: add rescheduling points during loop detection walks")
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: fix spurious set element insertion failure

On some platforms there is a padding hole in the nft_verdict
structure, between the verdict code and the chain pointer.

On element insertion, if the new element clashes with an existing one and
NLM_F_EXCL flag isn't set, we want to ignore the -EEXIST error as long as
the data associated with duplicated element is the same as the existing
one. The data equality check uses memcmp.

For normal data (NFT_DATA_VALUE) this works fine, but for NFT_DATA_VERDICT
padding area leads to spurious failure even if the verdict data is the
same.

This then makes the insertion fail with 'already exists' error, even
though the new "key : data" matches an existing entry and userspace
told the kernel that it doesn't want to receive an error indication.

Fixes: c016c7e45ddf ("netfilter: nf_tables: honor NLM_F_EXCL flag in set element insertion")
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: do not ignore genmask when looking up chain by id

When adding a rule to a chain referring to its ID, if that chain had been
deleted on the same batch, the rule might end up referring to a deleted
chain.

This will lead to a WARNING like following:

[ 33.098431] ------------[ cut here ]------------
[ 33.098678] WARNING: CPU: 5 PID: 69 at net/netfilter/nf_tables_api.c:2037 nf_tables_chain_destroy+0x23d/0x260
[ 33.099217] Modules linked in:
[ 33.099388] CPU: 5 PID: 69 Comm: kworker/5:1 Not tainted 6.4.0+ #409
[ 33.099726] Workqueue: events nf_tables_trans_destroy_work
[ 33.100018] RIP: 0010:nf_tables_chain_destroy+0x23d/0x260
[ 33.100306] Code: 8b 7c 24 68 e8 64 9c ed fe 4c 89 e7 e8 5c 9c ed fe 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 89 c6 89 c7 c3 cc cc cc cc <0f> 0b 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 89 c6 89 c7
[ 33.101271] RSP: 0018:ffffc900004ffc48 EFLAGS: 00010202
[ 33.101546] RAX: 0000000000000001 RBX: ffff888006fc0a28 RCX: 0000000000000000
[ 33.101920] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 33.102649] RBP: ffffc900004ffc78 R08: 0000000000000000 R09: 0000000000000000
[ 33.103018] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880135ef500
[ 33.103385] R13: 0000000000000000 R14: dead000000000122 R15: ffff888006fc0a10
[ 33.103762] FS: 0000000000000000(0000) GS:ffff888024c80000(0000) knlGS:0000000000000000
[ 33.104184] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 33.104493] CR2: 00007fe863b56a50 CR3: 00000000124b0001 CR4: 0000000000770ee0
[ 33.104872] PKRU: 55555554
[ 33.104999] Call Trace:
[ 33.105113] <TASK>
[ 33.105214] ? show_regs+0x72/0x90
[ 33.105371] ? __warn+0xa5/0x210
[ 33.105520] ? nf_tables_chain_destroy+0x23d/0x260
[ 33.105732] ? report_bug+0x1f2/0x200
[ 33.105902] ? handle_bug+0x46/0x90
[ 33.106546] ? exc_invalid_op+0x19/0x50
[ 33.106762] ? asm_exc_invalid_op+0x1b/0x20
[ 33.106995] ? nf_tables_chain_destroy+0x23d/0x260
[ 33.107249] ? nf_tables_chain_destroy+0x30/0x260
[ 33.107506] nf_tables_trans_destroy_work+0x669/0x680
[ 33.107782] ? mark_held_locks+0x28/0xa0
[ 33.107996] ? __pfx_nf_tables_trans_destroy_work+0x10/0x10
[ 33.108294] ? _raw_spin_unlock_irq+0x28/0x70
[ 33.108538] process_one_work+0x68c/0xb70
[ 33.108755] ? lock_acquire+0x17f/0x420
[ 33.108977] ? __pfx_process_one_work+0x10/0x10
[ 33.109218] ? do_raw_spin_lock+0x128/0x1d0
[ 33.109435] ? _raw_spin_lock_irq+0x71/0x80
[ 33.109634] worker_thread+0x2bd/0x700
[ 33.109817] ? __pfx_worker_thread+0x10/0x10
[ 33.110254] kthread+0x18b/0x1d0
[ 33.110410] ? __pfx_kthread+0x10/0x10
[ 33.110581] ret_from_fork+0x29/0x50
[ 33.110757] </TASK>
[ 33.110866] irq event stamp: 1651
[ 33.111017] hardirqs last enabled at (1659): [<ffffffffa206a209>] __up_console_sem+0x79/0xa0
[ 33.111379] hardirqs last disabled at (1666): [<ffffffffa206a1ee>] __up_console_sem+0x5e/0xa0
[ 33.111740] softirqs last enabled at (1616): [<ffffffffa1f5d40e>] __irq_exit_rcu+0x9e/0xe0
[ 33.112094] softirqs last disabled at (1367): [<ffffffffa1f5d40e>] __irq_exit_rcu+0x9e/0xe0
[ 33.112453] ---[ end trace 0000000000000000 ]---

This is due to the nft_chain_lookup_byid ignoring the genmask. After this
change, adding the new rule will fail as it will not find the chain.

Fixes: 837830a4b439 ("netfilter: nf_tables: add NFTA_RULE_CHAIN_ID attribute")
Cc: stable@vger.kernel.org
Reported-by: Mingi Cho of Theori working with ZDI
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: report use refcount overflow

Overflow use refcount checks are not complete.

Add helper function to deal with object reference counter tracking.
Report -EMFILE in case UINT_MAX is reached.

nft_use_dec() splats in case that reference counter underflows,
which should not ever happen.

Add nft_use_inc_restore() and nft_use_dec_restore() which are used
to restore reference counter from error and abort paths.

Use u32 in nft_flowtable and nft_object since helper functions cannot
work on bitfields.

Remove the few early incomplete checks now that the helper functions
are in place and used to check for refcount overflow.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix underflow in chain reference counter

Set element addition error path decrements reference counter on chains
twice: once on element release and again via nft_data_release().

Then, d6b478666ffa ("netfilter: nf_tables: fix underflow in object
reference counter") incorrectly fixed this by removing the stateful
object reference count decrement.

Restore the stateful object decrement as in b91d90368837 ("netfilter:
nf_tables: fix leaking object reference count") and let
nft_data_release() decrement the chain reference counter, so this is
done only once.

Fixes: d6b478666ffa ("netfilter: nf_tables: fix underflow in object reference counter")
Fixes: 628bd3e49cba ("netfilter: nf_tables: drop map element references from preparation phase")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: unbind non-anonymous set if rule construction fails

Otherwise a dangling reference to a rule object that is gone remains
in the set binding list.

Fixes: 26b5a5712eb8 ("netfilter: nf_tables: add NFT_TRANS_PREPARE_ERROR to deal with bound set/chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET

Analogous to NFT_MSG_GETOBJ_RESET, but for set elements with a timeout
or attached stateful expressions like counters or quotas - reset them
all at once. Respect a per element timeout value if present to reset the
'expires' value to.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: permit update of set size

Now that set->nelems is always updated permit update of the sets max size.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Fix for deleting base chains with payload

When deleting a base chain, iptables-nft simply submits the whole chain
to the kernel, including the NFTA_CHAIN_HOOK attribute. The new code
added by fixed commit then turned this into a chain update, destroying
the hook but not the chain itself. Detect the situation by checking if
the chain type is either netdev or inet/ingress.

Fixes: 7d937b107108f ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: drop module reference after updating chain

Otherwise the module reference counter is leaked.

Fixes b9703ed44ffb ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow timeout for anonymous sets

Never used from userspace, disallow these parameters.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow updates of anonymous sets

Disallow updates of set timeout and garbage collection parameters for
anonymous sets.

Fixes: 123b99619cca ("netfilter: nf_tables: honor set timeout and garbage collection updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject unbound chain set before commit phase

Use binding list to track set transaction and to check for unbound
chains before entering the commit phase.

Bail out if chain binding remain unused before entering the commit
step.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reject unbound anonymous set before commit phase

Add a new list to track set transaction and to check for unbound
anonymous sets before entering the commit phase.

Bail out at the end of the transaction handling if an anonymous set
remains unbound.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow element updates of bound anonymous sets

Anonymous sets come with NFT_SET_CONSTANT from userspace. Although API
allows to create anonymous sets without NFT_SET_CONSTANT, it makes no
sense to allow to add and to delete elements for bound anonymous sets.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix underflow in object reference counter

Since ("netfilter: nf_tables: drop map element references from
preparation phase"), integration with commit protocol is better,
therefore drop the workaround that b91d90368837 ("netfilter: nf_tables:
fix leaking object reference count") provides.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: drop map element references from preparation phase

set .destroy callback releases the references to other objects in maps.
This is very late and it results in spurious EBUSY errors. Drop refcount
from the preparation phase instead, update set backend not to drop
reference counter from set .destroy path.

Exceptions: NFT_TRANS_PREPARE_ERROR does not require to drop the
reference counter because the transaction abort path releases the map
references for each element since the set is unbound. The abort path
also deals with releasing reference counter for new elements added to
unbound sets.

Fixes: 591054469b3e ("netfilter: nf_tables: revisit chain/object refcounting from elements")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add NFT_TRANS_PREPARE_ERROR to deal with bound set/chain

Add a new state to deal with rule expressions deactivation from the
newrule error path, otherwise the anonymous set remains in the list in
inactive state for the next generation. Mark the set/chain transaction
as unbound so the abort path releases this object, set it as inactive in
the next generation so it is not reachable anymore from this transaction
and reference counter is dropped.

Fixes: 1240eb93f061 ("netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix chain binding transaction logic

Add bound flag to rule and chain transactions as in 6a0a8d10a366
("netfilter: nf_tables: use-after-free in failing rule with bound set")
to skip them in case that the chain is already bound from the abort
path.

This patch fixes an imbalance in the chain use refcnt that triggers a
WARN_ON on the table and chain destroy path.

This patch also disallows nested chain bindings, which is not
supported from userspace.

The logic to deal with chain binding in nft_data_hold() and
nft_data_release() is not correct. The NFT_TRANS_PREPARE state needs a
special handling in case a chain is bound but next expressions in the
same rule fail to initialize as described by 1240eb93f061 ("netfilter:
nf_tables: incorrect error path handling with NFT_MSG_NEWRULE").

The chain is left bound if rule construction fails, so the objects
stored in this chain (and the chain itself) are released by the
transaction records from the abort path, follow up patch ("netfilter:
nf_tables: add NFT_TRANS_PREPARE_ERROR to deal with bound set/chain")
completes this error handling.

When deleting an existing rule, chain bound flag is set off so the
rule expression .destroy path releases the objects.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE

In case of error when adding a new rule that refers to an anonymous set,
deactivate expressions via NFT_TRANS_PREPARE state, not NFT_TRANS_RELEASE.
Thus, the lookup expression marks anonymous sets as inactive in the next
generation to ensure it is not reachable in this transaction anymore and
decrement the set refcount as introduced by c1592a89942e ("netfilter:
nf_tables: deactivate anonymous set from preparation phase"). The abort
step takes care of undoing the anonymous set.

This is also consistent with rule deletion, where NFT_TRANS_PREPARE is
used. Note that this error path is exercised in the preparation step of
the commit protocol. This patch replaces nf_tables_rule_release() by the
deactivate and destroy calls, this time with NFT_TRANS_PREPARE.

Due to this incorrect error handling, it is possible to access a
dangling pointer to the anonymous set that remains in the transaction
list.

[1009.379054] BUG: KASAN: use-after-free in nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379106] Read of size 8 at addr ffff88816c4c8020 by task nft-rule-add/137110
[1009.379116] CPU: 7 PID: 137110 Comm: nft-rule-add Not tainted 6.4.0-rc4+ #256
[1009.379128] Call Trace:
[1009.379132] <TASK>
[1009.379135] dump_stack_lvl+0x33/0x50
[1009.379146] ? nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379191] print_address_description.constprop.0+0x27/0x300
[1009.379201] kasan_report+0x107/0x120
[1009.379210] ? nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379255] nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379302] nft_lookup_init+0xa5/0x270 [nf_tables]
[1009.379350] nf_tables_newrule+0x698/0xe50 [nf_tables]
[1009.379397] ? nf_tables_rule_release+0xe0/0xe0 [nf_tables]
[1009.379441] ? kasan_unpoison+0x23/0x50
[1009.379450] nfnetlink_rcv_batch+0x97c/0xd90 [nfnetlink]
[1009.379470] ? nfnetlink_rcv_msg+0x480/0x480 [nfnetlink]
[1009.379485] ? __alloc_skb+0xb8/0x1e0
[1009.379493] ? __alloc_skb+0xb8/0x1e0
[1009.379502] ? entry_SYSCALL_64_after_hwframe+0x46/0xb0
[1009.379509] ? unwind_get_return_address+0x2a/0x40
[1009.379517] ? write_profile+0xc0/0xc0
[1009.379524] ? avc_lookup+0x8f/0xc0
[1009.379532] ? __rcu_read_unlock+0x43/0x60

Fixes: 958bee14d071 ("netfilter: nf_tables: use new transaction infrastructure to handle sets")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: integrate pipapo into commit protocol

The pipapo set backend follows copy-on-update approach, maintaining one
clone of the existing datastructure that is being updated. The clone
and current datastructures are swapped via rcu from the commit step.

The existing integration with the commit protocol is flawed because
there is no operation to clean up the clone if the transaction is
aborted. Moreover, the datastructure swap happens on set element
activation.

This patch adds two new operations for sets: commit and abort, these new
operations are invoked from the commit and abort steps, after the
transactions have been digested, and it updates the pipapo set backend
to use it.

This patch adds a new ->pending_update field to sets to maintain a list
of sets that require this new commit and abort operations.

Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: out-of-bound check in chain blob

Add current size of rule expressions to the boundary check.

Fixes: 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Add null check for nla_nest_start_noflag() in nft_dump_basechain_hook()

The nla_nest_start_noflag() function may fail and return NULL;
the return value needs to be checked.

Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with SVACE.

Fixes: d54725cd11a5 ("netfilter: nf_tables: support for multiple devices per netdev hook")
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: always increment set element count

At this time, set->nelems counter only increments when the set has
a maximum size.

All set elements decrement the counter unconditionally, this is
confusing.

Increment the counter unconditionally to make this symmetrical.
This would also allow changing the set maximum size after set creation
in a later patch.

Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: fix nft_trans type confusion

nft_trans_FOO objects all share a common nft_trans base structure, but
trailing fields depend on the real object size. Access is only safe after
trans->msg_type check.

Check for rule type first. Found by code inspection.

Fixes: 1a94e38d254b ("netfilter: nf_tables: add NFTA_RULE_ID attribute")
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: deactivate anonymous set from preparation phase

Toggle deleted anonymous sets as inactive in the next generation, so
users cannot perform any update on it. Clear the generation bitmask
in case the transaction is aborted.

The following KASAN splat shows a set element deletion for a bound
anonymous set that has been already removed in the same transaction.

[ 64.921510] ==================================================================
[ 64.923123] BUG: KASAN: wild-memory-access in nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.924745] Write of size 8 at addr dead000000000122 by task test/890
[ 64.927903] CPU: 3 PID: 890 Comm: test Not tainted 6.3.0+ #253
[ 64.931120] Call Trace:
[ 64.932699] <TASK>
[ 64.934292] dump_stack_lvl+0x33/0x50
[ 64.935908] ? nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.937551] kasan_report+0xda/0x120
[ 64.939186] ? nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.940814] nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.942452] ? __kasan_slab_alloc+0x2d/0x60
[ 64.944070] ? nf_tables_setelem_notify+0x190/0x190 [nf_tables]
[ 64.945710] ? kasan_set_track+0x21/0x30
[ 64.947323] nfnetlink_rcv_batch+0x709/0xd90 [nfnetlink]
[ 64.948898] ? nfnetlink_rcv_msg+0x480/0x480 [nfnetlink]

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: hit ENOENT on unexisting chain/flowtable update with missing attributes

If user does not specify hook number and priority, then assume this is
a chain/flowtable update. Therefore, report ENOENT which provides a
better hint than EINVAL. Set on extended netlink error report to refer
to the chain name.

Fixes: 5b6743fb2c2a ("netfilter: nf_tables: skip flowtable hooknum and priority on device updates")
Fixes: 5efe72698a97 ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: allow to create netdev chain without device

Relax netdev chain creation to allow for loading the ruleset, then
adding/deleting devices at a later stage. Hardware offload does not
support for this feature yet.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: support for deleting devices in an existing netdev chain

This patch allows for deleting devices in an existing netdev chain.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: support for adding new devices to an existing netdev chain

This patch allows users to add devices to an existing netdev chain.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: rename function to destroy hook list

Rename nft_flowtable_hooks_destroy() by nft_hooks_destroy() to prepare
for netdev chain device updates.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not send complete notification of deletions

In most cases, table, name and handle is sufficient for userspace to
identify an object that has been deleted. Skipping unneeded fields in
the netlink attributes in the message saves bandwidth (ie. less chances
of hitting ENOBUFS).

Rules are an exception: the existing userspace monitor code relies on
the rule definition. This exception can be removed by implementing a
rule cache in userspace, this is already supported by the tracing
infrastructure.

Regarding flowtables, incremental deletion of devices is possible.
Skipping a full notification allows userspace to differentiate between
flowtable removal and incremental removal of devices.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: extended netlink error reporting for netdevice

Flowtable and netdev chains are bound to one or several netdevice,
extend netlink error reporting to specify the the netdevice that
triggers the error.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: make validation state per table

We only need to validate tables that saw changes in the current
transaction.

The existing code revalidates all tables, but this isn't needed as
cross-table jumps are not allowed (chains have table scope).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: don't write table validation state without mutex

The ->cleanup callback needs to be removed, this doesn't work anymore as
the transaction mutex is already released in the ->abort function.

Just do it after a successful validation pass, this either happens
from commit or abort phases where transaction mutex is held.

Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: don't store chain address on jump

Now that the rule trailer/end marker and the rcu head reside in the
same structure, we no longer need to save/restore the chain pointer
when performing/returning from a jump.

We can simply let the trace infra walk the evaluated rule until it
hits the end marker and then fetch the chain pointer from there.

When the rule is NULL (policy tracing), then chain and basechain
pointers were already identical, so just use the basechain.

This cuts size of jumpstack in half, from 256 to 128 bytes in 64bit,
scripts/stackusage says:

nf_tables_core.c:251 nft_do_chain 328 static

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: merge nft_rules_old structure and end of ruleblob marker

In order to free the rules in a chain via call_rcu, the rule array used
to stash a rcu_head and space for a pointer at the end of the rule array.

When the current nft_rule_dp blob format got added in
2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout"), this results
in a double-trailer:

size (unsigned long)
struct nft_rule_dp
struct nft_expr
...
struct nft_rule_dp
struct nft_expr
...
struct nft_rule_dp (is_last=1) // Trailer

The trailer, struct nft_rule_dp (is_last=1), is not accounted for in size,
so it can be located via start_addr + size.

Because the rcu_head is stored after 'start+size' as well this means the
is_last trailer is *aliased* to the rcu_head (struct nft_rules_old).

This is harmless, because at this time the nft_do_chain function never
evaluates/accesses the trailer, it only checks the address boundary:

for (; rule < last_rule; rule = nft_rule_next(rule)) {
...

But this way the last_rule address has to be stashed in the jump
structure to restore it after returning from a chain.

nft_do_chain stack usage has become way too big, so put it on a diet.

Without this patch is impossible to use
for (; !rule->is_last; rule = nft_rule_next(rule)) {

... because on free, the needed update of the rcu_head will clobber the
nft_rule_dp is_last bit.

Furthermore, also stash the chain pointer in the trailer, this allows
to recover the original chain structure from nf_tables_trace infra
without a need to place them in the jump struct.

After this patch it is trivial to diet the jump stack structure,
done in the next two patches.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: tighten netlink attribute requirements for catch-all elements

If NFT_SET_ELEM_CATCHALL is set on, then userspace provides no set element
key. Otherwise, bail out with -EINVAL.

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: validate catch-all set elements

catch-all set element might jump/goto to chain that uses expressions
that require validation.

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Modify nla_memdup's flag to GFP_KERNEL_ACCOUNT

For memory alloc that store user data from nla[NFTA_OBJ_USERDATA],
use GFP_KERNEL_ACCOUNT is more suitable.

Fixes: 33758c891479 ("memcg: enable accounting for nft objects")
Signed-off-by: Chen Aotian <chenaotian2@163.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: allow to fetch set elements when table has an owner

NFT_MSG_GETSETELEM returns -EPERM when fetching set elements that belong
to table that has an owner. This results in empty set/map listing from
userspace.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix wrong pointer passed to PTR_ERR()

It should be 'chain' passed to PTR_ERR() in the error path
after calling nft_chain_lookup() in nf_tables_delrule().

Fixes: f80a612dd77c ("netfilter: nf_tables: add support to destroy operation")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: NULL pointer dereference in nf_tables_updobj()

static analyzer detect null pointer dereference case for 'type'
function __nft_obj_type_get() can return NULL value which require to handle
if type is NULL pointer return -ENOENT.

This is a theoretical issue, since an existing object has a type, but
better add this failsafe check.

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add support to destroy operation

Introduce NFT_MSG_DESTROY* message type. The destroy operation performs a
delete operation but ignoring the ENOENT errors.

This is useful for the transaction semantics, where failing to delete an
object which does not exist results in aborting the transaction.

This new command allows the transaction to proceed in case the object
does not exist.

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: honor set timeout and garbage collection updates

Set timeout and garbage collection interval updates are ignored on
updates. Add transaction to update global set element timeout and
garbage collection interval.

Fixes: 96518518cc41 ("netfilter: add nftables")
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: perform type checking for existing sets

If a ruleset declares a set name that matches an existing set in the
kernel, then validate that this declaration really refers to the same
set, otherwise bail out with EEXIST.

Currently, the kernel reports success when adding a set that already
exists in the kernel. This usually results in EINVAL errors at a later
stage, when the user adds elements to the set, if the set declaration
mismatches the existing set representation in the kernel.

Add a new function to check that the set declaration really refers to
the same existing set in the kernel.

Fixes: 96518518cc41 ("netfilter: add nftables")
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add function to create set stateful expressions

Add a helper function to allocate and initialize the stateful expressions
that are defined in a set.

This patch allows to reuse this code from the set update path, to check
that type of the update matches the existing set in the kernel.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: consolidate set description

Add the following fields to the set description:

- key type
- data type
- object type
- policy
- gc_int: garbage collection interval)
- timeout: element timeout

This prepares for stricter set type checks on updates in a follow up
patch.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_inner: fix IS_ERR() vs NULL check

The __nft_expr_type_get() function returns NULL on error. It never
returns error pointers.

Fixes: 3a07327d10a0 ("netfilter: nft_inner: support for inner tunnel header matching")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Introduce NFT_MSG_GETRULE_RESET

Analogous to NFT_MSG_GETOBJ_RESET, but for rules: Reset stateful
expressions like counters or quotas. The latter two are the only
consumers, adjust their 'dump' callbacks to respect the parameter
introduced earlier.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Extend nft_expr_ops::dump callback parameters

Add a 'reset' flag just like with nft_object_ops::dump. This will be
useful to reset "anonymous stateful objects", e.g. simple rule counters.

No functional change intended.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: Remove the obsolte u64_stats_fetch_*_irq() users (net).

Now that the 32bit UP oddity is gone and 32bit uses always a sequence
count, there is no need for the fetch_irq() variants anymore.

Convert to the regular interface.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

netfilter: nft_inner: support for inner tunnel header matching

This new expression allows you to match on the inner headers that are
encapsulated by any of the existing tunneling protocols.

This expression parses the inner packet to set the link, network and
transport offsets, so the existing expressions (with a few updates) can
be reused to match on the inner headers.

The inner expression supports for different tunnel combinations such as:

- ethernet frame over IPv4/IPv6 packet, eg. VxLAN.
- IPv4/IPv6 packet over IPv4/IPv6 packet, eg. IPIP.
- IPv4/IPv6 packet over IPv4/IPv6 + transport header, eg. GRE.
- transport header (ESP or SCTP) over transport header (usually UDP)

The following fields are used to describe the tunnel protocol:

- flags, which describe how to parse the inner headers:

NFT_PAYLOAD_CTX_INNER_TUN, the tunnel provides its own header.
NFT_PAYLOAD_CTX_INNER_ETHER, the ethernet frame is available as inner header.
NFT_PAYLOAD_CTX_INNER_NH, the network header is available as inner header.
NFT_PAYLOAD_CTX_INNER_TH, the transport header is available as inner header.

For example, VxLAN sets on all of these flags. While GRE only sets on
NFT_PAYLOAD_CTX_INNER_NH and NFT_PAYLOAD_CTX_INNER_TH. Then, ESP over
UDP only sets on NFT_PAYLOAD_CTX_INNER_TH.

The tunnel description is composed of the following attributes:

- header size: in case the tunnel comes with its own header, eg. VxLAN.

- type: this provides a hint to userspace on how to delinearize the rule.
This is useful for VxLAN and Geneve since they run over UDP, since
transport does not provide a hint. This is also useful in case hardware
offload is ever supported. The type is not currently interpreted by the
kernel.

- expression: currently only payload supported. Follow up patch adds
also inner meta support which is required by autogenerated
dependencies. The exthdr expression should be supported too
at some point. There is a new inner_ops operation that needs to be
set on to allow to use an existing expression from the inner expression.

This patch adds a new NFT_PAYLOAD_TUN_HEADER base which allows to match
on the tunnel header fields, eg. vxlan vni.

The payload expression is embedded into nft_inner private area and this
private data area is passed to the payload inner eval function via
direct call.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not set up extensions for end interval

Elements with an end interval flag set on do not store extensions. The
global set definition is currently setting on the timeout and stateful
expression for end interval elements.

This leads to skipping end interval elements from the set->ops->walk()
path as the expired check bogusly reports true.

Moreover, do not set up stateful expressions for elements with end
interval flag set on since this is never used.

Fixes: 65038428b2c6 ("netfilter: nf_tables: allow to specify stateful expression in set definition")
Fixes: 8d8540c4f5e0 ("netfilter: nft_set_rbtree: add timeout support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Cleanup nft_net->module_list from nf_tables_exit_net()

syzbot reported a warning like below [1]:

WARNING: CPU: 3 PID: 9 at net/netfilter/nf_tables_api.c:10096 nf_tables_exit_net+0x71c/0x840
Modules linked in:
CPU: 2 PID: 9 Comm: kworker/u8:0 Tainted: G W 6.1.0-rc3-00072-g8e5423e991e8 #47
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:nf_tables_exit_net+0x71c/0x840
...
Call Trace:
<TASK>
? __nft_release_table+0xfc0/0xfc0
ops_exit_list+0xb5/0x180
cleanup_net+0x506/0xb10
? unregister_pernet_device+0x80/0x80
process_one_work+0xa38/0x1730
? pwq_dec_nr_in_flight+0x2b0/0x2b0
? rwlock_bug.part.0+0x90/0x90
? _raw_spin_lock_irq+0x46/0x50
worker_thread+0x67e/0x10e0
? process_one_work+0x1730/0x1730
kthread+0x2e5/0x3a0
? kthread_complete_and_exit+0x40/0x40
ret_from_fork+0x1f/0x30
</TASK>

In nf_tables_exit_net(), there is a case where nft_net->commit_list is
empty but nft_net->module_list is not empty. Such a case occurs with
the following scenario:

1. nfnetlink_rcv_batch() is called
2. nf_tables_newset() returns -EAGAIN and NFNL_BATCH_FAILURE bit is
set to status
3. nf_tables_abort() is called with NFNL_ABORT_AUTOLOAD
(nft_net->commit_list is released, but nft_net->module_list is not
because of NFNL_ABORT_AUTOLOAD flag)
4. Jump to replay label
5. netlink_skb_clone() fails and returns from the function (this is
caused by fault injection in the reproducer of syzbot)

This patch fixes this issue by calling __nf_tables_abort() when
nft_net->module_list is not empty in nf_tables_exit_net().

Fixes: eb014de4fd41 ("netfilter: nf_tables: autoload modules from the abort path")
Link: https://syzkaller.appspot.com/bug?id=802aba2422de4218ad0c01b46c9525cc9d4e4aa3 [1]
Reported-by: syzbot+178efee9e2d7f87f5103@syzkaller.appspotmail.com
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: release flow rule object from commit path

No need to postpone this to the commit release path, since no packets
are walking over this object, this is accessed from control plane only.
This helped uncovered UAF triggered by races with the netlink notifier.

Fixes: 9dd732e0bdf5 ("netfilter: nf_tables: memleak flow rule from commit path")
Reported-by: syzbot+8f747f62763bc6c32916@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: netlink notifier might race to release objects

commit release path is invoked via call_rcu and it runs lockless to
release the objects after rcu grace period. The netlink notifier handler
might win race to remove objects that the transaction context is still
referencing from the commit release path.

Call rcu_barrier() to ensure pending rcu callbacks run to completion
if the list of transactions to be destroyed is not empty.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Reported-by: syzbot+8f747f62763bc6c32916@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: relax NFTA_SET_ELEM_KEY_END set flags requirements

Otherwise EINVAL is bogusly reported to userspace when deleting a set
element. NFTA_SET_ELEM_KEY_END does not need to be set in case of:

- insertion: if not present, start key is used as end key.
- deletion: only start key needs to be specified, end key is ignored.

Hence, relax the sanity check.

Fixes: 88cccd908d51 ("netfilter: nf_tables: NFTA_SET_ELEM_KEY_END requires concat and interval flags")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: fix percpu memory leak at nf_tables_addchain()

It seems to me that percpu memory for chain stats started leaking since
commit 3bc158f8d0330f0a ("netfilter: nf_tables: map basechain priority to
hardware priority") when nft_chain_offload_priority() returned an error.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 3bc158f8d0330f0a ("netfilter: nf_tables: map basechain priority to hardware priority")
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain()

syzbot is reporting underflow of nft_counters_enabled counter at
nf_tables_addchain() [1], for commit 43eb8949cfdffa76 ("netfilter:
nf_tables: do not leave chain stats enabled on error") missed that
nf_tables_chain_destroy() after nft_basechain_init() in the error path of
nf_tables_addchain() decrements the counter because nft_basechain_init()
makes nft_is_base_chain() return true by setting NFT_CHAIN_BASE flag.

Increment the counter immediately after returning from
nft_basechain_init().

Link: https://syzkaller.appspot.com/bug?extid=b5d82a651b71cd8a75ab [1]
Reported-by: syzbot <syzbot+b5d82a651b71cd8a75ab@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+b5d82a651b71cd8a75ab@syzkaller.appspotmail.com>
Fixes: 43eb8949cfdffa76 ("netfilter: nf_tables: do not leave chain stats enabled on error")
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nf_tables: clean up hook list when offload flags check fails

splice back the hook list so nft_chain_release_hook() has a chance to
release the hooks.

BUG: memory leak
unreferenced object 0xffff88810180b100 (size 96):
comm "syz-executor133", pid 3619, jiffies 4294945714 (age 12.690s)
hex dump (first 32 bytes):
28 64 23 02 81 88 ff ff 28 64 23 02 81 88 ff ff (d#.....(d#.....
90 a8 aa 83 ff ff ff ff 00 00 b5 0f 81 88 ff ff ................
backtrace:
[<ffffffff83a8c59b>] kmalloc include/linux/slab.h:600 [inline]
[<ffffffff83a8c59b>] nft_netdev_hook_alloc+0x3b/0xc0 net/netfilter/nf_tables_api.c:1901
[<ffffffff83a9239a>] nft_chain_parse_netdev net/netfilter/nf_tables_api.c:1998 [inline]
[<ffffffff83a9239a>] nft_chain_parse_hook+0x33a/0x530 net/netfilter/nf_tables_api.c:2073
[<ffffffff83a9b14b>] nf_tables_addchain.constprop.0+0x10b/0x950 net/netfilter/nf_tables_api.c:2218
[<ffffffff83a9c41b>] nf_tables_newchain+0xa8b/0xc60 net/netfilter/nf_tables_api.c:2593
[<ffffffff83a3d6a6>] nfnetlink_rcv_batch+0xa46/0xd20 net/netfilter/nfnetlink.c:517
[<ffffffff83a3db79>] nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:638 [inline]
[<ffffffff83a3db79>] nfnetlink_rcv+0x1f9/0x220 net/netfilter/nfnetlink.c:656
[<ffffffff83a13b17>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
[<ffffffff83a13b17>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345
[<ffffffff83a13fd6>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921
[<ffffffff83865ab6>] sock_sendmsg_nosec net/socket.c:714 [inline]
[<ffffffff83865ab6>] sock_sendmsg+0x56/0x80 net/socket.c:734
[<ffffffff8386601c>] ____sys_sendmsg+0x36c/0x390 net/socket.c:2482
[<ffffffff8386a918>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536
[<ffffffff8386aaa8>] __sys_sendmsg+0x88/0x100 net/socket.c:2565
[<ffffffff845e5955>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff845e5955>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: d54725cd11a5 ("netfilter: nf_tables: support for multiple devices per netdev hook")
Reported-by: syzbot+5fcdbfab6d6744c57418@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow binding to already bound chain

Update nft_data_init() to report EINVAL if chain is already bound.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Reported-by: Gwangun Jung <exsociety@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not leave chain stats enabled on error

Error might occur later in the nf_tables_addchain() codepath, enable
static key only after transaction has been created.

Fixes: 9f08ea848117 ("netfilter: nf_tables: keep chain counters away from hot path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: make table handle allocation per-netns friendly

mutex is per-netns, move table_netns to the pernet area.

*read-write* to 0xffffffff883a01e8 of 8 bytes by task 6542 on cpu 0:
nf_tables_newtable+0x6dc/0xc00 net/netfilter/nf_tables_api.c:1221
nfnetlink_rcv_batch net/netfilter/nfnetlink.c:513 [inline]
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline]
nfnetlink_rcv+0xa6a/0x13a0 net/netfilter/nfnetlink.c:652
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x652/0x730 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x643/0x740 net/netlink/af_netlink.c:1921

Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions")
Reported-by: Abhishek Shah <abhishek.shah@columbia.edu>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow updates of implicit chain

Updates on existing implicit chain make no sense, disallow this.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: check NFT_SET_CONCAT flag if field_count is specified

Since f3a2181e16f1 ("netfilter: nf_tables: Support for sets with
multiple ranged fields"), it possible to combine intervals and
concatenations. Later on, ef516e8625dd ("netfilter: nf_tables:
reintroduce the NFT_SET_CONCAT flag") provides the NFT_SET_CONCAT flag
for userspace to report that the set stores a concatenation.

Make sure NFT_SET_CONCAT is set on if field_count is specified for
consistency. Otherwise, if NFT_SET_CONCAT is specified with no
field_count, bail out with EINVAL.

Fixes: ef516e8625dd ("netfilter: nf_tables: reintroduce the NFT_SET_CONCAT flag")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow NFT_SET_ELEM_CATCHALL and NFT_SET_ELEM_INTERVAL_END

These flags are mutually exclusive, report EINVAL in this case.

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: NFTA_SET_ELEM_KEY_END requires concat and interval flags

If the NFT_SET_CONCAT|NFT_SET_INTERVAL flags are set on, then the
netlink attribute NFTA_SET_ELEM_KEY_END must be specified. Otherwise,
NFTA_SET_ELEM_KEY_END should not be present.

For catch-all element, NFTA_SET_ELEM_KEY_END should not be present.
The NFT_SET_ELEM_INTERVAL_END is never used with this set flags
combination.

Fixes: 7b225d0b5c6d ("netfilter: nf_tables: add NFTA_SET_ELEM_KEY_END attribute")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: validate NFTA_SET_ELEM_OBJREF based on NFT_SET_OBJECT flag

If the NFTA_SET_ELEM_OBJREF netlink attribute is present and
NFT_SET_OBJECT flag is set on, report EINVAL.

Move existing sanity check earlier to validate that NFT_SET_OBJECT
requires NFTA_SET_ELEM_OBJREF.

Fixes: 8aeff920dcc9 ("netfilter: nf_tables: add stateful object reference to set elements")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: really skip inactive sets when allocating name

While looping to build the bitmap of used anonymous set names, check the
current set in the iteration, instead of the one that is being created.

Fixes: 37a9cc525525 ("netfilter: nf_tables: add generation mask to sets")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix scheduling-while-atomic splat

nf_tables_check_loops() can be called from rhashtable list
walk so cond_resched() cannot be used here.

Fixes: 81ea01066741 ("netfilter: nf_tables: add rescheduling points during loop detection walks")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: possible module reference underflow in error path

dst->ops is set on when nft_expr_clone() fails, but module refcount has
not been bumped yet, therefore nft_expr_destroy() leads to module
reference underflow.

Fixes: 8cfd9b0f8515 ("netfilter: nftables: generalize set expressions support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow NFTA_SET_ELEM_KEY_END with NFT_SET_ELEM_INTERVAL_END flag

These are mutually exclusive, actually NFTA_SET_ELEM_KEY_END replaces
the flag notation.

Fixes: 7b225d0b5c6d ("netfilter: nf_tables: add NFTA_SET_ELEM_KEY_END attribute")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: use READ_ONCE and WRITE_ONCE for shared generation id access

The generation ID is bumped from the commit path while holding the
mutex, however, netlink dump operations rely on RCU.

This patch also adds missing cb->base_eq initialization in
nf_tables_dump_set().

Fixes: 38e029f14a97 ("netfilter: nf_tables: set NLM_F_DUMP_INTR if netlink dumping is stale")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix null deref due to zeroed list head

In nf_tables_updtable, if nf_tables_table_enable returns an error,
nft_trans_destroy is called to free the transaction object.

nft_trans_destroy() calls list_del(), but the transaction was never
placed on a list -- the list head is all zeroes, this results in
a null dereference:

BUG: KASAN: null-ptr-deref in nft_trans_destroy+0x26/0x59
Call Trace:
nft_trans_destroy+0x26/0x59
nf_tables_newtable+0x4bc/0x9bc
[..]

Its sane to assume that nft_trans_destroy() can be called
on the transaction object returned by nft_trans_alloc(), so
make sure the list head is initialised.

Fixes: 55dd6f93076b ("netfilter: nf_tables: use new transaction infrastructure to handle table")
Reported-by: mingi cho <mgcho.minic@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow jump to implicit chain from set element

Extend struct nft_data_desc to add a flag field that specifies
nft_data_init() is being called for set element data.

Use it to disallow jump to implicit chain from set element, only jump
to chain via immediate expression is allowed.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: upfront validation of data via nft_data_init()

Instead of parsing the data and then validate that type and length are
correct, pass a description of the expected data so it can be validated
upfront before parsing it to bail out earlier.

This patch adds a new .size field to specify the maximum size of the
data area. The .len field is optional and it is used as an input/output
field, it provides the specific length of the expected data in the input
path. If then .len field is not specified, then obtained length from the
netlink attribute is stored. This is required by cmp, bitwise, range and
immediate, which provide no netlink attribute that describes the data
length. The immediate expression uses the destination register type to
infer the expected data type.

Relying on opencoded validation of the expected data might lead to
subtle bugs as described in 7e6bc1f6cabc ("netfilter: nf_tables:
stricter validation of element data").

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not allow RULE_ID to refer to another chain

When doing lookups for rules on the same batch by using its ID, a rule from
a different chain can be used. If a rule is added to a chain but tries to
be positioned next to a rule from a different chain, it will be linked to
chain2, but the use counter on chain1 would be the one to be incremented.

When looking for rules by ID, use the chain that was used for the lookup by
name. The chain used in the context copied to the transaction needs to
match that same chain. That way, struct nft_rule does not need to get
enlarged with another member.

Fixes: 1a94e38d254b ("netfilter: nf_tables: add NFTA_RULE_ID attribute")
Fixes: 75dd48e2e420 ("netfilter: nf_tables: Support RULE_ID reference in new rule")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not allow CHAIN_ID to refer to another table

When doing lookups for chains on the same batch by using its ID, a chain
from a different table can be used. If a rule is added to a table but
refers to a chain in a different table, it will be linked to the chain in
table2, but would have expressions referring to objects in table1.

Then, when table1 is removed, the rule will not be removed as its linked to
a chain in table2. When expressions in the rule are processed or removed,
that will lead to a use-after-free.

When looking for chains by ID, use the table that was used for the lookup
by name, and only return chains belonging to that same table.

Fixes: 837830a4b439 ("netfilter: nf_tables: add NFTA_RULE_CHAIN_ID attribute")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not allow SET_ID to refer to another table

When doing lookups for sets on the same batch by using its ID, a set from a
different table can be used.

Then, when the table is removed, a reference to the set may be kept after
the set is freed, leading to a potential use-after-free.

When looking for sets by ID, use the table that was used for the lookup by
name, and only return sets belonging to that same table.

This fixes CVE-2022-2586, also reported as ZDI-CAN-17470.

Reported-by: Team Orca of Sea Security (@seasecresponse)
Fixes: 958bee14d071 ("netfilter: nf_tables: use new transaction infrastructure to handle sets")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: validate variable length element extension

Update template to validate variable length extensions. This patch adds
a new .ext_len[id] field to the template to store the expected extension
length. This is used to sanity check the initialization of the variable
length extension.

Use PTR_ERR() in nft_set_elem_init() to report errors since, after this
update, there are two reason why this might fail, either because of
ENOMEM or insufficient room in the extension field (EINVAL).

Kernels up until 7e6bc1f6cabc ("netfilter: nf_tables: stricter
validation of element data") allowed to copy more data to the extension
than was allocated. This ext_len field allows to validate if the
destination has the correct size as additional check.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add rescheduling points during loop detection walks

Add explicit rescheduling points during ruleset walk.

Switching to a faster algorithm is possible but this is a much
smaller change, suitable for nf tree.

Link: https://bugzilla.netfilter.org/show_bug.cgi?id=1460
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: replace BUG_ON by element length check

BUG_ON can be triggered from userspace with an element with a large
userdata area. Replace it by length check and return EINVAL instead.
Over time extensions have been growing in size.

Pick a sufficiently old Fixes: tag to propagate this fix.

Fixes: 7d7402642eaf ("netfilter: nf_tables: variable sized set element keys / data")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: stricter validation of element data

Make sure element data type and length do not mismatch the one specified
by the set declaration.

Fixes: 7d7402642eaf ("netfilter: nf_tables: variable sized set element keys / data")
Reported-by: Hugues ANGUELKOV <hanguelkov@randorisec.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: bail out early if hardware offload is not supported

If user requests for NFT_CHAIN_HW_OFFLOAD, then check if either device
provides the .ndo_setup_tc interface or there is an indirect flow block
that has been registered. Otherwise, bail out early from the preparation
phase. Moreover, validate that family == NFPROTO_NETDEV and hook is
NF_NETDEV_INGRESS.

Fixes: c9626a2cbdb2 ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: memleak flow rule from commit path

Abort path release flow rule object, however, commit path does not.
Update code to destroy these objects before releasing the transaction.

Fixes: c9626a2cbdb2 ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: release new hooks on unsupported flowtable flags

Release the list of new hooks that are pending to be registered in case
that unsupported flowtable flags are provided.

Fixes: 78d9f48f7f44 ("netfilter: nf_tables: add devices to existing flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: always initialize flowtable hook list in transaction

The hook list is used if nft_trans_flowtable_update(trans) == true. However,
initialize this list for other cases for safety reasons.

Fixes: 78d9f48f7f44 ("netfilter: nf_tables: add devices to existing flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: delete flowtable hooks via transaction list

Remove inactive bool field in nft_hook object that was introduced in
abadb2f865d7 ("netfilter: nf_tables: delete devices from flowtable").
Move stale flowtable hooks to transaction list instead.

Deleting twice the same device does not result in ENOENT.

Fixes: abadb2f865d7 ("netfilter: nf_tables: delete devices from flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: use kfree_rcu(ptr, rcu) to release hooks in clean_net path

Use kfree_rcu(ptr, rcu) variant instead as described by ae089831ff28
("netfilter: nf_tables: prefer kfree_rcu(ptr, rcu) variant").

Fixes: f9a43007d3f7 ("netfilter: nf_tables: double hook unregistration in netns path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: double hook unregistration in netns path

__nft_release_hooks() is called from pre_netns exit path which
unregisters the hooks, then the NETDEV_UNREGISTER event is triggered
which unregisters the hooks again.

[ 565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270
[...]
[ 565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G E 5.18.0-rc7+ #27
[ 565.253682] Workqueue: netns cleanup_net
[ 565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270
[...]
[ 565.297120] Call Trace:
[ 565.300900] <TASK>
[ 565.304683] nf_tables_flowtable_event+0x16a/0x220 [nf_tables]
[ 565.308518] raw_notifier_call_chain+0x63/0x80
[ 565.312386] unregister_netdevice_many+0x54f/0xb50

Unregister and destroy netdev hook from netns pre_exit via kfree_rcu
so the NETDEV_UNREGISTER path see unregistered hooks.

Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: hold mutex on netns pre_exit path

clean_net() runs in workqueue while walking over the lists, grab mutex.

Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: sanitize nft_set_desc_concat_parse()

Add several sanity checks for nft_set_desc_concat_parse():

- validate desc->field_count not larger than desc->field_len array.
- field length cannot be larger than desc->field_len (ie. U8_MAX)
- total length of the concatenation cannot be larger than register array.

Joint work with Florian Westphal.

Fixes: f3a2181e16f1 ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Reported-by: <zhangziming.zzm@antgroup.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: set element extended ACK reporting support

Report the element that causes problems via netlink extended ACK for set
element commands.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disallow non-stateful expression in sets earlier

Since 3e135cd499bf ("netfilter: nft_dynset: dynamic stateful expression
instantiation"), it is possible to attach stateful expressions to set
elements.

cd5125d8f518 ("netfilter: nf_tables: split set destruction in deactivate
and destroy phase") introduces conditional destruction on the object to
accomodate transaction semantics.

nft_expr_init() calls expr->ops->init() first, then check for
NFT_STATEFUL_EXPR, this stills allows to initialize a non-stateful
lookup expressions which points to a set, which might lead to UAF since
the set is not properly detached from the set->binding for this case.
Anyway, this combination is non-sense from nf_tables perspective.

This patch fixes this problem by checking for NFT_STATEFUL_EXPR before
expr->ops->init() is called.

The reporter provides a KASAN splat and a poc reproducer (similar to
those autogenerated by syzbot to report use-after-free errors). It is
unknown to me if they are using syzbot or if they use similar automated
tool to locate the bug that they are reporting.

For the record, this is the KASAN splat.

[ 85.431824] ==================================================================
[ 85.432901] BUG: KASAN: use-after-free in nf_tables_bind_set+0x81b/0xa20
[ 85.433825] Write of size 8 at addr ffff8880286f0e98 by task poc/776
[ 85.434756]
[ 85.434999] CPU: 1 PID: 776 Comm: poc Tainted: G W 5.18.0+ #2
[ 85.436023] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014

Fixes: 0b2d8a7b638b ("netfilter: nf_tables: add helper functions for expression handling")
Reported-and-tested-by: Aaron Adams <edg-e@nccgroup.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: replace unnecessary use of list_for_each_entry_continue()

Since there is no way for list_for_each_entry_continue() to start
interating in the middle of the list they can be replaced with a call
to list_for_each_entry().

In preparation to limit the scope of the list iterator to the list
traversal loop, the list iterator variable 'rule' should not be used
past the loop.

v1->v2:
- also replace first usage of list_for_each_entry_continue() (Florian
Westphal)

Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disable expression reduction infra

Either userspace or kernelspace need to pre-fetch keys inconditionally
before comparisons for this to work. Otherwise, register tracking data
is misleading and it might result in reducing expressions which are not
yet registers.

First expression is also guaranteed to be evaluated always, however,
certain expressions break before writing data to registers, before
comparing the data, leaving the register in undetermined state.

This patch disables this infrastructure by now.

Fixes: b2d306542ff9 ("netfilter: nf_tables: do not reduce read-only expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: nft_parse_register can return a negative value

Since commit 6e1acfa387b9 ("netfilter: nf_tables: validate registers
coming from userspace.") nft_parse_register can return a negative value,
but the function prototype is still returning an unsigned int.

Fixes: 6e1acfa387b9 ("netfilter: nf_tables: validate registers coming from userspace.")
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: memcg accounting for dynamically allocated objects

nft_*.c files whose NFT_EXPR_STATEFUL flag is set on need to
use __GFP_ACCOUNT flag for objects that are dynamically
allocated from the packet path.

Such objects are allocated inside nft_expr_ops->init() callbacks
executed in task context while processing netlink messages.

In addition, this patch adds accounting to nft_set_elem_expr_clone()
used for the same purposes.

Signed-off-by: Vasily Averin <vvs@openvz.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

memcg: enable accounting for nft objects

nftables replaces iptables, but it lacks memcg accounting.

This patch account most of the memory allocation associated with nft
and should protect the host from misusing nft inside a memcg restricted
container.

Signed-off-by: Vasily Averin <vvs@openvz.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: cancel tracking for clobbered destination registers

Output of expressions might be larger than one single register, this might
clobber existing data. Reset tracking for all destination registers that
required to store the expression output.

This patch adds three new helper functions:

- nft_reg_track_update: cancel previous register tracking and update it.
- nft_reg_track_cancel: cancel any previous register tracking info.
- __nft_reg_track_cancel: cancel only one single register tracking info.

Partial register clobbering detection is also supported by checking the
.num_reg field which describes the number of register that are used.

This patch updates the following expressions:

- meta_bridge
- bitwise
- byteorder
- meta
- payload

to use these helper functions.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not reduce read-only expressions

Skip register tracking for expressions that perform read-only operations
on the registers. Define and use a cookie pointer NFT_REDUCE_READONLY to
avoid defining stubs for these expressions.

This patch re-enables register tracking which was disabled in ed5f85d42290
("netfilter: nf_tables: disable register tracking"). Follow up patches
add remaining register tracking for existing expressions.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: validate registers coming from userspace.

Bail out in case userspace uses unsupported registers.

Fixes: 49499c3e6e18 ("netfilter: nf_tables: switch registers to 32 bit addressing")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Reject tables of unsupported family

An nftables family is merely a hollow container, its family just a
number and such not reliant on compile-time options other than nftables
support itself. Add an artificial check so attempts at using a family
the kernel can't support fail as early as possible. This helps user
space detect kernels which lack e.g. NFPROTO_INET.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: disable register tracking

The register tracking infrastructure is incomplete, it might lead to
generating incorrect ruleset bytecode, disable it by now given we are
late in the release process.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: prefer kfree_rcu(ptr, rcu) variant

While kfree_rcu(ptr) _is_ supported, it has some limitations.

Given that 99.99% of kfree_rcu() users [1] use the legacy
two parameters variant, and @catchall objects do have an rcu head,
simply use it.

Choice of kfree_rcu(ptr) variant was probably not intentional.

[1] including calls from net/netfilter/nf_tables_api.c

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix memory leak during stateful obj update

stateful objects can be updated from the control plane.
The transaction logic allocates a temporary object for this purpose.

The ->init function was called for this object, so plain kfree() leaks
resources. We must call ->destroy function of the object.

nft_obj_destroy does this, but it also decrements the module refcount,
but the update path doesn't increment it.

To avoid special-casing the update object release, do module_get for
the update case too and release it via nft_obj_destroy().

Fixes: d62d0ba97b58 ("netfilter: nf_tables: Introduce stateful object update operation")
Cc: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: unregister flowtable hooks on netns exit

Unregister flowtable hooks before they are releases via
nf_tables_flowtable_destroy() otherwise hook core reports UAF.

BUG: KASAN: use-after-free in nf_hook_entries_grow+0x5a7/0x700 net/netfilter/core.c:142 net/netfilter/core.c:142
Read of size 4 at addr ffff8880736f7438 by task syz-executor579/3666

CPU: 0 PID: 3666 Comm: syz-executor579 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
__dump_stack lib/dump_stack.c:88 [inline] lib/dump_stack.c:106
dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 lib/dump_stack.c:106
print_address_description+0x65/0x380 mm/kasan/report.c:247 mm/kasan/report.c:247
__kasan_report mm/kasan/report.c:433 [inline]
__kasan_report mm/kasan/report.c:433 [inline] mm/kasan/report.c:450
kasan_report+0x19a/0x1f0 mm/kasan/report.c:450 mm/kasan/report.c:450
nf_hook_entries_grow+0x5a7/0x700 net/netfilter/core.c:142 net/netfilter/core.c:142
__nf_register_net_hook+0x27e/0x8d0 net/netfilter/core.c:429 net/netfilter/core.c:429
nf_register_net_hook+0xaa/0x180 net/netfilter/core.c:571 net/netfilter/core.c:571
nft_register_flowtable_net_hooks+0x3c5/0x730 net/netfilter/nf_tables_api.c:7232 net/netfilter/nf_tables_api.c:7232
nf_tables_newflowtable+0x2022/0x2cf0 net/netfilter/nf_tables_api.c:7430 net/netfilter/nf_tables_api.c:7430
nfnetlink_rcv_batch net/netfilter/nfnetlink.c:513 [inline]
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline]
nfnetlink_rcv_batch net/netfilter/nfnetlink.c:513 [inline] net/netfilter/nfnetlink.c:652
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline] net/netfilter/nfnetlink.c:652
nfnetlink_rcv+0x10e6/0x2550 net/netfilter/nfnetlink.c:652 net/netfilter/nfnetlink.c:652

__nft_release_hook() calls nft_unregister_flowtable_net_hooks() which
only unregisters the hooks, then after RCU grace period, it is
guaranteed that no packets add new entries to the flowtable (no flow
offload rules and flowtable hooks are reachable from packet path), so it
is safe to call nf_flow_table_free() which cleans up the remaining
entries from the flowtable (both software and hardware) and it unbinds
the flow_block.

Fixes: ff4bf2f42a40 ("netfilter: nf_tables: add nft_unregister_flowtable_hook()")
Reported-by: syzbot+e918523f77e62790d6d9@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: remove assignment with no effect in chain blob builder

cppcheck possible warnings:

>> net/netfilter/nf_tables_api.c:2014:2: warning: Assignment of function parameter has no effect outside the function. Did you forget dereferencing it? [uselessAssignmentPtrArg]
ptr += offsetof(struct nft_rule_dp, data);
^

Reported-by: kernel test robot <yujie.liu@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: set last expression in register tracking area

nft_rule_for_each_expr() sets on last to nft_rule_last(), however, this
is coming after track.last field is set on.

Use nft_expr_last() to set track.last accordingly.

Fixes: 12e4ecfa244b ("netfilter: nf_tables: add register tracking infrastructure")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: remove unused variable

> Remove unused variable and fix missing initialization.
>
> >> net/netfilter/nf_tables_api.c:8266:6: warning: variable 'i' set but not used [-Wunused-but-set-variable]
> int i;
> ^

Fixes: 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: don't use 'data_size' uninitialized

Commit 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout") never
initialized the new 'data_size' variable.

I'm not sure how it ever worked, but it might have worked almost by
accident - gcc seems to occasionally miss these kinds of 'variable used
uninitialized' situations, but I've seen it do so because it ended up
zero-initializing them due to some other simplification.

But clang is very unhappy about it all, and correctly reports

net/netfilter/nf_tables_api.c:8278:4: error: variable 'data_size' is uninitialized when used here [-Werror,-Wuninitialized]
data_size += sizeof(*prule) + rule->dlen;
^~~~~~~~~
net/netfilter/nf_tables_api.c:8263:30: note: initialize the variable 'data_size' to silence this warning
unsigned int size, data_size;
^
= 0
1 error generated.

and this fix just initializes 'data_size' to zero before the loop.

Fixes: 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout")
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

netfilter: nf_tables: add register tracking infrastructure

This patch adds new infrastructure to skip redundant selector store
operations on the same register to achieve a performance boost from
the packet path.

This is particularly noticeable in pure linear rulesets but it also
helps in rulesets which are already heaving relying in maps to avoid
ruleset linear inspection.

The idea is to keep data of the most recurrent store operations on
register to reuse them with cmp and lookup expressions.

This infrastructure allows for dynamic ruleset updates since the ruleset
blob reduction happens from the kernel.

Userspace still needs to be updated to maximize register utilization to
cooperate to improve register data reuse / reduce number of store on
register operations.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add rule blob layout

This patch adds a blob layout per chain to represent the ruleset in the
packet datapath.

size (unsigned long)
struct nft_rule_dp
struct nft_expr
...
struct nft_rule_dp
struct nft_expr
...
struct nft_rule_dp (is_last=1)

The new structure nft_rule_dp represents the rule in a more compact way
(smaller memory footprint) compared to the control-plane nft_rule
structure.

The ruleset blob is a read-only data structure. The first field contains
the blob size, then the rules containing expressions. There is a trailing
rule which is used by the tracing infrastructure which is equivalent to
the NULL rule marker in the previous representation. The blob size field
does not include the size of this trailing rule marker.

The ruleset blob is generated from the commit path.

This patch reuses the infrastructure available since 0cbc06b3faba
("netfilter: nf_tables: remove synchronize_rcu in commit phase") to
build the array of rules per chain.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix use-after-free in nft_set_catchall_destroy()

We need to use list_for_each_entry_safe() iterator
because we can not access @catchall after kfree_rcu() call.

syzbot reported:

BUG: KASAN: use-after-free in nft_set_catchall_destroy net/netfilter/nf_tables_api.c:4486 [inline]
BUG: KASAN: use-after-free in nft_set_destroy net/netfilter/nf_tables_api.c:4504 [inline]
BUG: KASAN: use-after-free in nft_set_destroy+0x3fd/0x4f0 net/netfilter/nf_tables_api.c:4493
Read of size 8 at addr ffff8880716e5b80 by task syz-executor.3/8871

CPU: 1 PID: 8871 Comm: syz-executor.3 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x2ed mm/kasan/report.c:247
__kasan_report mm/kasan/report.c:433 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:450
nft_set_catchall_destroy net/netfilter/nf_tables_api.c:4486 [inline]
nft_set_destroy net/netfilter/nf_tables_api.c:4504 [inline]
nft_set_destroy+0x3fd/0x4f0 net/netfilter/nf_tables_api.c:4493
__nft_release_table+0x79f/0xcd0 net/netfilter/nf_tables_api.c:9626
nft_rcv_nl_event+0x4f8/0x670 net/netfilter/nf_tables_api.c:9688
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
blocking_notifier_call_chain kernel/notifier.c:318 [inline]
blocking_notifier_call_chain+0x67/0x90 kernel/notifier.c:306
netlink_release+0xcb6/0x1dd0 net/netlink/af_netlink.c:788
__sock_release+0xcd/0x280 net/socket.c:649
sock_close+0x18/0x20 net/socket.c:1314
__fput+0x286/0x9f0 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f75fbf28adb
Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffd8da7ec10 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f75fbf28adb
RDX: 00007f75fc08e828 RSI: ffffffffffffffff RDI: 0000000000000003
RBP: 00007f75fc08a960 R08: 0000000000000000 R09: 00007f75fc08e830
R10: 00007ffd8da7ed10 R11: 0000000000000293 R12: 00000000002067c3
R13: 00007ffd8da7ed10 R14: 00007f75fc088f60 R15: 0000000000000032
</TASK>

Allocated by task 8886:
kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
____kasan_kmalloc mm/kasan/common.c:472 [inline]
__kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:522
kasan_kmalloc include/linux/kasan.h:269 [inline]
kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3575
kmalloc include/linux/slab.h:590 [inline]
nft_setelem_catchall_insert net/netfilter/nf_tables_api.c:5544 [inline]
nft_setelem_insert net/netfilter/nf_tables_api.c:5562 [inline]
nft_add_set_elem+0x232e/0x2f40 net/netfilter/nf_tables_api.c:5936
nf_tables_newsetelem+0x6ff/0xbb0 net/netfilter/nf_tables_api.c:6032
nfnetlink_rcv_batch+0x1710/0x25f0 net/netfilter/nfnetlink.c:513
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline]
nfnetlink_rcv+0x3af/0x420 net/netfilter/nfnetlink.c:652
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x904/0xdf0 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:704 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:724
____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
___sys_sendmsg+0xf3/0x170 net/socket.c:2463
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2492
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 15335:
kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free mm/kasan/common.c:328 [inline]
__kasan_slab_free+0xd1/0x110 mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:235 [inline]
__cache_free mm/slab.c:3445 [inline]
kmem_cache_free_bulk+0x67/0x1e0 mm/slab.c:3766
kfree_bulk include/linux/slab.h:446 [inline]
kfree_rcu_work+0x51c/0xa10 kernel/rcu/tree.c:3273
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Last potentially related work creation:
kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
__kasan_record_aux_stack+0xb5/0xe0 mm/kasan/generic.c:348
kvfree_call_rcu+0x74/0x990 kernel/rcu/tree.c:3550
nft_set_catchall_destroy net/netfilter/nf_tables_api.c:4489 [inline]
nft_set_destroy net/netfilter/nf_tables_api.c:4504 [inline]
nft_set_destroy+0x34a/0x4f0 net/netfilter/nf_tables_api.c:4493
__nft_release_table+0x79f/0xcd0 net/netfilter/nf_tables_api.c:9626
nft_rcv_nl_event+0x4f8/0x670 net/netfilter/nf_tables_api.c:9688
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
blocking_notifier_call_chain kernel/notifier.c:318 [inline]
blocking_notifier_call_chain+0x67/0x90 kernel/notifier.c:306
netlink_release+0xcb6/0x1dd0 net/netlink/af_netlink.c:788
__sock_release+0xcd/0x280 net/socket.c:649
sock_close+0x18/0x20 net/socket.c:1314
__fput+0x286/0x9f0 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff8880716e5b80
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes inside of
64-byte region [ffff8880716e5b80, ffff8880716e5bc0)
The buggy address belongs to the page:
page:ffffea0001c5b940 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880716e5c00 pfn:0x716e5
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0000911848 ffffea00007c4d48 ffff888010c40200
raw: ffff8880716e5c00 ffff8880716e5000 000000010000001e 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x242040(__GFP_IO|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 3638, ts 211086074437, free_ts 211031029429
prep_new_page mm/page_alloc.c:2418 [inline]
get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4149
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369
__alloc_pages_node include/linux/gfp.h:570 [inline]
kmem_getpages mm/slab.c:1377 [inline]
cache_grow_begin+0x75/0x470 mm/slab.c:2593
cache_alloc_refill+0x27f/0x380 mm/slab.c:2965
____cache_alloc mm/slab.c:3048 [inline]
____cache_alloc mm/slab.c:3031 [inline]
__do_cache_alloc mm/slab.c:3275 [inline]
slab_alloc mm/slab.c:3316 [inline]
__do_kmalloc mm/slab.c:3700 [inline]
__kmalloc+0x3b3/0x4d0 mm/slab.c:3711
kmalloc include/linux/slab.h:595 [inline]
kzalloc include/linux/slab.h:724 [inline]
tomoyo_get_name+0x234/0x480 security/tomoyo/memory.c:173
tomoyo_parse_name_union+0xbc/0x160 security/tomoyo/util.c:260
tomoyo_update_path_number_acl security/tomoyo/file.c:687 [inline]
tomoyo_write_file+0x629/0x7f0 security/tomoyo/file.c:1034
tomoyo_write_domain2+0x116/0x1d0 security/tomoyo/common.c:1152
tomoyo_add_entry security/tomoyo/common.c:2042 [inline]
tomoyo_supervisor+0xbc7/0xf00 security/tomoyo/common.c:2103
tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline]
tomoyo_path_number_perm+0x419/0x590 security/tomoyo/file.c:734
security_file_ioctl+0x50/0xb0 security/security.c:1541
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0xb3/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1338 [inline]
free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1389
free_unref_page_prepare mm/page_alloc.c:3309 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3388
slab_destroy mm/slab.c:1627 [inline]
slabs_destroy+0x89/0xc0 mm/slab.c:1647
cache_flusharray mm/slab.c:3418 [inline]
___cache_free+0x4cc/0x610 mm/slab.c:3480
qlink_free mm/kasan/quarantine.c:146 [inline]
qlist_free_all+0x4e/0x110 mm/kasan/quarantine.c:165
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
__kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:259 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc_node mm/slab.c:3261 [inline]
kmem_cache_alloc_node+0x2ea/0x590 mm/slab.c:3599
__alloc_skb+0x215/0x340 net/core/skbuff.c:414
alloc_skb include/linux/skbuff.h:1126 [inline]
nlmsg_new include/net/netlink.h:953 [inline]
rtmsg_ifinfo_build_skb+0x72/0x1a0 net/core/rtnetlink.c:3808
rtmsg_ifinfo_event net/core/rtnetlink.c:3844 [inline]
rtmsg_ifinfo_event net/core/rtnetlink.c:3835 [inline]
rtmsg_ifinfo+0x83/0x120 net/core/rtnetlink.c:3853
netdev_state_change net/core/dev.c:1395 [inline]
netdev_state_change+0x114/0x130 net/core/dev.c:1386
linkwatch_do_dev+0x10e/0x150 net/core/link_watch.c:167
__linkwatch_run_queue+0x233/0x6a0 net/core/link_watch.c:213
linkwatch_event+0x4a/0x60 net/core/link_watch.c:252
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298

Memory state around the buggy address:
ffff8880716e5a80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8880716e5b00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff8880716e5b80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffff8880716e5c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8880716e5c80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: honor NLM_F_CREATE and NLM_F_EXCL in event notification

Include the NLM_F_CREATE and NLM_F_EXCL flags in netlink event
notifications, otherwise userspace cannot distiguish between create and
add commands.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: reverse order in rule replacement expansion

Deactivate old rule first, then append the new rule, so rule replacement
notification via netlink first reports the deletion of the old rule with
handle X in first place, then it adds the new rule (reusing the handle X
of the replaced old rule).

Note that the abort path releases the transaction that has been created
by nft_delrule() on error.

Fixes: ca08987885a1 ("netfilter: nf_tables: deactivate expressions in rule replecement routine")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add position handle in event notification

Add position handle to allow to identify the rule location from netlink
events. Otherwise, userspace cannot incrementally update a userspace
cache through monitoring events.

Skip handle dump if the rule has been either inserted (at the beginning
of the ruleset) or appended (at the end of the ruleset), the
NLM_F_APPEND netlink flag is sufficient in these two cases.

Handle NLM_F_REPLACE as NLM_F_APPEND since the rule replacement
expansion appends it after the specified rule handle.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Fix oversized kvmalloc() calls

The commit 7661809d493b ("mm: don't allow oversized kvmalloc() calls")
limits the max allocatable memory via kvmalloc() to MAX_INT.

Reported-by: syzbot+cd43695a64bcd21b8596@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: unlink table before deleting it

syzbot reports following UAF:
BUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955
nla_strcmp+0xf2/0x130 lib/nlattr.c:836
nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570
nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline]
nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064
nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504

Problem is that all get operations are lockless, so the commit_mutex
held by nft_rcv_nl_event() isn't enough to stop a parallel GET request
from doing read-accesses to the table object even after synchronize_rcu().

To avoid this, unlink the table first and store the table objects in
on-stack scratch space.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Reported-and-tested-by: syzbot+f31660cf279b0557160c@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix audit memory leak in nf_tables_commit

In nf_tables_commit, if nf_tables_commit_audit_alloc fails, it does not
free the adp variable.

Fix this by adding nf_tables_commit_audit_free which frees
the linked list with the head node adl.

backtrace:
kmalloc include/linux/slab.h:591 [inline]
kzalloc include/linux/slab.h:721 [inline]
nf_tables_commit_audit_alloc net/netfilter/nf_tables_api.c:8439 [inline]
nf_tables_commit+0x16e/0x1760 net/netfilter/nf_tables_api.c:8508
nfnetlink_rcv_batch+0x512/0xa80 net/netfilter/nfnetlink.c:562
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline]
nfnetlink_rcv+0x1fa/0x220 net/netfilter/nfnetlink.c:652
netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
netlink_unicast+0x2c7/0x3e0 net/netlink/af_netlink.c:1340
netlink_sendmsg+0x36b/0x6b0 net/netlink/af_netlink.c:1929
sock_sendmsg_nosec net/socket.c:702 [inline]
sock_sendmsg+0x56/0x80 net/socket.c:722

Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-by: kernel test robot <lkp@intel.com>
Fixes: c520292f29b8 ("audit: log nftables configuration change events once per table")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Fix dereference of null pointer flow

In the case where chain->flags & NFT_CHAIN_HW_OFFLOAD is false then
nft_flow_rule_create is not called and flow is NULL. The subsequent
error handling execution via label err_destroy_flow_rule will lead
to a null pointer dereference on flow when calling nft_flow_rule_destroy.
Since the error path to err_destroy_flow_rule has to cater for null
and non-null flows, only call nft_flow_rule_destroy if flow is non-null
to fix this issue.

Addresses-Coverity: ("Explicity null dereference")
Fixes: 3c5e44622011 ("netfilter: nf_tables: memleak in hw offload abort path")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not allow to delete table with owner by handle

nft_table_lookup_byhandle() also needs to validate the netlink PortID
owner when deleting a table by handle.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: skip netlink portID validation if zero

nft_table_lookup() allows us to obtain the table object by the name and
the family. The netlink portID validation needs to be skipped for the
dump path, since the ownership only applies to commands to update the
given table. Skip validation if the specified netlink PortID is zero
when calling nft_table_lookup().

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: memleak in hw offload abort path

Release flow from the abort path, this is easy to reproduce since
b72920f6e4a9 ("netfilter: nftables: counter hardware offload support").
If the preparation phase fails, then the abort path is exercised without
releasing the flow rule object.

unreferenced object 0xffff8881f0fa7700 (size 128):
comm "nft", pid 1335, jiffies 4294931120 (age 4163.740s)
hex dump (first 32 bytes):
08 e4 de 13 82 88 ff ff 98 e4 de 13 82 88 ff ff ................
48 e4 de 13 82 88 ff ff 01 00 00 00 00 00 00 00 H...............
backtrace:
[<00000000634547e7>] flow_rule_alloc+0x26/0x80
[<00000000c8426156>] nft_flow_rule_create+0xc9/0x3f0 [nf_tables]
[<0000000075ff8e46>] nf_tables_newrule+0xc79/0x10a0 [nf_tables]
[<00000000ba65e40e>] nfnetlink_rcv_batch+0xaac/0xf90 [nfnetlink]
[<00000000505c614a>] nfnetlink_rcv+0x1bb/0x1f0 [nfnetlink]
[<00000000eb78e1fe>] netlink_unicast+0x34b/0x480
[<00000000a8f72c94>] netlink_sendmsg+0x3af/0x690
[<000000009cb1ddf4>] sock_sendmsg+0x96/0xa0
[<0000000039d06e44>] ____sys_sendmsg+0x3fe/0x440
[<00000000137e82ca>] ___sys_sendmsg+0xd8/0x140
[<000000000c6bf6a6>] __sys_sendmsg+0xb3/0x130
[<0000000043bd6268>] do_syscall_64+0x40/0xb0
[<00000000afdebc2d>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Remove flow rule release from the offload commit path, otherwise error
from the offload commit phase might trigger a double-free due to the
execution of the abort_offload -> abort. After this patch, the abort
path takes care of releasing the flow rule.

This fix also needs to move the nft_flow_rule_create() call before the
transaction object is added otherwise the abort path might find a NULL
pointer to the flow rule object for the NFT_CHAIN_HW_OFFLOAD case.

While at it, rename BASIC-like goto tags to slightly more meaningful
names rather than adding a new "err3" tag.

Fixes: 63b48c73ff56 ("netfilter: nf_tables_offload: undo updates if transaction fails")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: move base hook annotation to init helper

coverity scanner says:
2187 if (nft_is_base_chain(chain)) {
vvv CID 1505166: Memory - corruptions (UNINIT)
vvv Using uninitialized value "basechain".
2188 basechain->ops.hook_ops_type = NF_HOOK_OP_NF_TABLES;

... I don't see how nft_is_base_chain() can evaluate to true
while basechain pointer is garbage.

However, it seems better to place the NF_HOOK_OP_NF_TABLES annotation
in nft_basechain_hook_init() instead.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1505166 ("Memory - corruptions")
Fixes: 65b8b7bfc5284f ("netfilter: annotate nf_tables base hook ops")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: annotate nf_tables base hook ops

This will allow a followup patch to treat the 'ops->priv' pointer
as nft_chain argument without having to first walk the table/chains
to check if there is a matching base chain pointer.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: remove nft_ctx_init_from_setattr()

Replace nft_ctx_init_from_setattr() by nft_table_lookup().

This patch also disentangles nf_tables_delset() where NFTA_SET_TABLE is
required while nft_ctx_init_from_setattr() allows it to be optional.

From the nf_tables_delset() path, this also allows to set up the context
structure when it is needed.

Removing this helper function saves us 14 LoC, so it is not helping to
consolidate code.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: remove nft_ctx_init_from_elemattr()

Replace nft_ctx_init_from_elemattr() by nft_table_lookup() and set up
the context structure right before it is really needed.

Moreover, nft_ctx_init_from_elemattr() is setting up the context
structure for codepaths where this is not really needed at all.

This helper function is also not helping to consolidate code, removing
it saves us 4 LoC.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: add struct nfgenmsg to struct nfnl_info and use it

Update the nfnl_info structure to add a pointer to the nfnetlink header.
This simplifies the existing codebase since this header is usually
accessed. Update existing clients to use this new field.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: initialize set before expression setup

nft_set_elem_expr_alloc() needs an initialized set if expression sets on
the NFT_EXPR_GC flag. Move set fields initialization before expression
setup.

[4512935.019450] ==================================================================
[4512935.019456] BUG: KASAN: null-ptr-deref in nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables]
[4512935.019487] Read of size 8 at addr 0000000000000070 by task nft/23532
[4512935.019494] CPU: 1 PID: 23532 Comm: nft Not tainted 5.12.0-rc4+ #48
[...]
[4512935.019502] Call Trace:
[4512935.019505] dump_stack+0x89/0xb4
[4512935.019512] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables]
[4512935.019536] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables]
[4512935.019560] kasan_report.cold.12+0x5f/0xd8
[4512935.019566] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables]
[4512935.019590] nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables]
[4512935.019615] nf_tables_newset+0xc7f/0x1460 [nf_tables]

Reported-by: syzbot+ce96ca2b1d0b37c6422d@syzkaller.appspotmail.com
Fixes: 65038428b2c6 ("netfilter: nf_tables: allow to specify stateful expression in set definition")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: fix table flag updates

The dormant flag need to be updated from the preparation phase,
otherwise, two consecutive requests to dorm a table in the same batch
might try to remove the same hooks twice, resulting in the following
warning:

hook not found, pf 3 num 0
WARNING: CPU: 0 PID: 334 at net/netfilter/core.c:480 __nf_unregister_net_hook+0x1eb/0x610 net/netfilter/core.c:480
Modules linked in:
CPU: 0 PID: 334 Comm: kworker/u4:5 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:__nf_unregister_net_hook+0x1eb/0x610 net/netfilter/core.c:480

This patch is a partial revert of 0ce7cf4127f1 ("netfilter: nftables:
update table flags from the commit phase") to restore the previous
behaviour.

However, there is still another problem: A batch containing a series of
dorm-wakeup-dorm table and vice-versa also trigger the warning above
since hook unregistration happens from the preparation phase, while hook
registration occurs from the commit phase.

To fix this problem, this patch adds two internal flags to annotate the
original dormant flag status which are __NFT_TABLE_F_WAS_DORMANT and
__NFT_TABLE_F_WAS_AWAKEN, to restore it from the abort path.

The __NFT_TABLE_F_UPDATE bitmask allows to handle the dormant flag update
with one single transaction.

Reported-by: syzbot+7ad5cd1615f2d89c6e7e@syzkaller.appspotmail.com
Fixes: 0ce7cf4127f1 ("netfilter: nftables: update table flags from the commit phase")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: extended netlink error reporting for chain type

Users that forget to select the NAT chain type in netfilter's Kconfig
hit ENOENT when adding the basechain.

This report is however sparse since it might be the table, the chain
or the kernel module that is missing/does not exist.

This patch provides extended netlink error reporting for the
NFTA_CHAIN_TYPE netlink attribute, which conveys the basechain type.
If the user selects a basechain that his custom kernel does not support,
the netlink extended error provides a more accurate hint on the
described issue.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: missing error reporting for not selected expressions

Sometimes users forget to turn on nftables extensions from Kconfig that
they need. In such case, the error reporting from userspace is
misleading:

$ sudo nft add rule x y counter
Error: Could not process rule: No such file or directory
add rule x y counter
^^^^^^^^^^^^^^^^^^^^

Add missing NL_SET_BAD_ATTR() to provide a hint:

$ nft add rule x y counter
Error: Could not process rule: No such file or directory
add rule x y counter
^^^^^^^

Fixes: 83d9dcba06c5 ("netfilter: nf_tables: extended netlink error reporting for expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: avoid potential overflows on 32bit arches

User space could ask for very large hash tables, we need to make sure
our size computations wont overflow.

nf_tables_newset() needs to double check the u64 size
will fit into size_t field.

Fixes: 0ed6389c483d ("netfilter: nf_tables: rename set implementations")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: Fix a memleak from userdata error path in new objects

Release object name if userdata allocation fails.

Fixes: b131c96496b3 ("netfilter: nf_tables: add userdata support for nft_object")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add catch-all set element support

This patch extends the set infrastructure to add a special catch-all set
element. If the lookup fails to find an element (or range) in the set,
then the catch-all element is selected. Users can specify a mapping,
expression(s) and timeout to be attached to the catch-all element.

This patch adds a catchall list to the set, this list might contain more
than one single catch-all element (e.g. in case that the catch-all
element is removed and a new one is added in the same transaction).
However, most of the time, there will be either one element or no
elements at all in this list.

The catch-all element is identified via NFT_SET_ELEM_CATCHALL flag and
such special element has no NFTA_SET_ELEM_KEY attribute. There is a new
nft_set_elem_catchall object that stores a reference to the dummy
catch-all element (catchall->elem) whose layout is the same of the set
element type to reuse the existing set element codebase.

The set size does not apply to the catch-all element, users can define a
catch-all element even if the set is full.

The check for valid set element flags hava been updates to report
EOPNOTSUPP in case userspace requests flags that are not supported when
using new userspace nftables and old kernel.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add helper function to validate set element data

When binding sets to rule, validate set element data according to
set definition. This patch adds a helper function to be reused by
the catch-all set element support.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add helper function to flush set elements

This patch adds nft_set_flush() which prepares for the catch-all
element support.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add loop check helper function

This patch adds nft_check_loops() to reuse it in the new catch-all
element codebase.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: rename set element data activation/deactivation functions

Rename:

- nft_set_elem_activate() to nft_set_elem_data_activate().
- nft_set_elem_deactivate() to nft_set_elem_data_deactivate().

To prepare for updates in the set element infrastructure to add support
for the special catch-all element.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: consolidate callback types

Add enum nfnl_callback_type to identify the callback type to provide one
single callback.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: pass struct nfnl_info to batch callbacks

Update batch callbacks to use the nfnl_info structure. Rename one
clashing info variable to expr_info.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: pass struct nfnl_info to rcu callbacks

Update rcu callbacks to use the nfnl_info structure.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add nft_pernet() helper function

Consolidate call to net_generic(net, nf_tables_net_id) in this
wrapper function.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: counter hardware offload support

This patch adds the .offload_stats operation to synchronize hardware
stats with the expression data. Update the counter expression to use
this new interface. The hardware stats are retrieved from the netlink
dump path via FLOW_CLS_STATS command to the driver.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: use net_generic infra for transaction data

This moves all nf_tables pernet data from struct net to a net_generic
extension, with the exception of the gencursor.

The latter is used in the data path and also outside of the nf_tables
core. All others are only used from the configuration plane.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: remove documentation on static functions

Since 4f16d25c68ec ("netfilter: nftables: add nft_parse_register_load()
and use it") and 345023b0db31 ("netfilter: nftables: add
nft_parse_register_store() and use it"), the following functions are not
exported symbols anymore:

- nft_parse_register()
- nft_validate_register_load()
- nft_validate_register_store()

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: fix a warning message in nf_tables_commit_audit_collect()

The first argument of a WARN_ONCE() is a condition. This WARN_ONCE()
will only print the table name, and is potentially problematic if the
table name has a %s in it.

Fixes: c520292f29b8 ("audit: log nftables configuration change events once per table")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add helper function to set up the nfnetlink header and use it

This patch adds a helper function to set up the netlink and nfnetlink headers.
Update existing codebase to use it.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add helper function to set the base sequence number

This patch adds a helper function to calculate the base sequence number
field that is stored in the nfnetlink header. Use the helper function
whenever possible.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: remove unnecessary spin_lock_init()

The spinlock nf_tables_destroy_list_lock is initialized statically.
It is unnecessary to initialize by spin_lock_init().

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

audit: log nftables configuration change events once per table

Reduce logging of nftables events to a level similar to iptables.
Restore the table field to list the table, adding the generation.

Indicate the op as the most significant operation in the event.

A couple of sample events:

type=PROCTITLE msg=audit(2021-03-18 09:30:49.801:143) : proctitle=/usr/bin/python3 -s /usr/sbin/firewalld --nofork --nopid
type=SYSCALL msg=audit(2021-03-18 09:30:49.801:143) : arch=x86_64 syscall=sendmsg success=yes exit=172 a0=0x6 a1=0x7ffdcfcbe650 a2=0x0 a3=0x7ffdcfcbd52c items=0 ppid=1 pid=367 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=roo
t sgid=root fsgid=root tty=(none) ses=unset comm=firewalld exe=/usr/bin/python3.9 subj=system_u:system_r:firewalld_t:s0 key=(null)
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.801:143) : table=firewalld:2 family=ipv6 entries=1 op=nft_register_table pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.801:143) : table=firewalld:2 family=ipv4 entries=1 op=nft_register_table pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.801:143) : table=firewalld:2 family=inet entries=1 op=nft_register_table pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld

type=PROCTITLE msg=audit(2021-03-18 09:30:49.839:144) : proctitle=/usr/bin/python3 -s /usr/sbin/firewalld --nofork --nopid
type=SYSCALL msg=audit(2021-03-18 09:30:49.839:144) : arch=x86_64 syscall=sendmsg success=yes exit=22792 a0=0x6 a1=0x7ffdcfcbe650 a2=0x0 a3=0x7ffdcfcbd52c items=0 ppid=1 pid=367 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=r
oot sgid=root fsgid=root tty=(none) ses=unset comm=firewalld exe=/usr/bin/python3.9 subj=system_u:system_r:firewalld_t:s0 key=(null)
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.839:144) : table=firewalld:3 family=ipv6 entries=30 op=nft_register_chain pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.839:144) : table=firewalld:3 family=ipv4 entries=30 op=nft_register_chain pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.839:144) : table=firewalld:3 family=inet entries=165 op=nft_register_chain pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld

The issue was originally documented in
https://github.com/linux-audit/audit-kernel/issues/124

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_log: perform module load from nf_tables

modprobe calls from the nf_logger_find_get() API causes deadlock in very
special cases because they occur with the nf_tables transaction mutex held.

In the specific case of nf_log, deadlock is via:

A nf_tables -> transaction mutex -> nft_log -> modprobe -> nf_log_syslog \
-> pernet_ops rwsem -> wait for C
B netlink event -> rtnl_mutex -> nf_tables transaction mutex -> wait for A
C close() -> ip6mr_sk_done -> rtnl_mutex -> wait for B

Earlier patch added NFLOG/xt_LOG module softdeps to avoid the need to load
the backend module during a transaction.

For nft_log we would have to add a softdep for both nfnetlink_log or
nf_log_syslog, since we do not know in advance which of the two backends
are going to be configured.

This defers the modprobe op until after the transaction mutex is released.

Tested-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: update table flags from the commit phase

Do not update table flags from the preparation phase. Store the flags
update into the transaction, then update the flags from the commit
phase.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break statements instead of just
letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: clone set element expression template

memcpy() breaks when using connlimit in set elements. Use
nft_expr_clone() to initialize the connlimit expression list, otherwise
connlimit garbage collector crashes when walking on the list head copy.

[ 493.064656] Workqueue: events_power_efficient nft_rhash_gc [nf_tables]
[ 493.064685] RIP: 0010:find_or_evict+0x5a/0x90 [nf_conncount]
[ 493.064694] Code: 2b 43 40 83 f8 01 77 0d 48 c7 c0 f5 ff ff ff 44 39 63 3c 75 df 83 6d 18 01 48 8b 43 08 48 89 de 48 8b 13 48 8b 3d ee 2f 00 00 <48> 89 42 08 48 89 10 48 b8 00 01 00 00 00 00 ad de 48 89 03 48 83
[ 493.064699] RSP: 0018:ffffc90000417dc0 EFLAGS: 00010297
[ 493.064704] RAX: 0000000000000000 RBX: ffff888134f38410 RCX: 0000000000000000
[ 493.064708] RDX: 0000000000000000 RSI: ffff888134f38410 RDI: ffff888100060cc0
[ 493.064711] RBP: ffff88812ce594a8 R08: ffff888134f38438 R09: 00000000ebb9025c
[ 493.064714] R10: ffffffff8219f838 R11: 0000000000000017 R12: 0000000000000001
[ 493.064718] R13: ffffffff82146740 R14: ffff888134f38410 R15: 0000000000000000
[ 493.064721] FS: 0000000000000000(0000) GS:ffff88840e440000(0000) knlGS:0000000000000000
[ 493.064725] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 493.064729] CR2: 0000000000000008 CR3: 00000001330aa002 CR4: 00000000001706e0
[ 493.064733] Call Trace:
[ 493.064737] nf_conncount_gc_list+0x8f/0x150 [nf_conncount]
[ 493.064746] nft_rhash_gc+0x106/0x390 [nf_tables]

Reported-by: Laura Garcia Liebana <nevola@gmail.com>
Fixes: 409444522976 ("netfilter: nf_tables: add elements with stateful expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: skip hook overlap logic if flowtable is stale

If the flowtable has been previously removed in this batch, skip the
hook overlap checks. This fixes spurious EEXIST errors when removing and
adding the flowtable in the same batch.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: allow to update flowtable flags

Honor flowtable flags from the control update path. Disallow disabling
to toggle hardware offload support though.

Fixes: 8bb69f3b2918 ("netfilter: nf_tables: add flowtable offload control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: report EOPNOTSUPP on unsupported flowtable flags

Error was not set accordingly.

Fixes: 8bb69f3b2918 ("netfilter: nf_tables: add flowtable offload control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: bogus check for netlink portID with table owner

The existing branch checks for 0 != table->nlpid which always evaluates
true for tables that have an owner.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: fix possible double hook unregistration with table owner

Skip hook unregistration of owner tables from the netns exit path,
nft_rcv_nl_event() unregisters the table hooks before tearing down
the table content.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: disallow updates on table ownership

Disallow updating the ownership bit on an existing table: Do not allow
to grab ownership on an existing table. Do not allow to drop ownership
on an existing table.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: introduce table ownership

A userspace daemon like firewalld might need to monitor for netlink
updates to detect its ruleset removal by the (global) flush ruleset
command to ensure ruleset persistency. This adds extra complexity from
userspace and, for some little time, the firewall policy is not in
place.

This patch adds the NFT_TABLE_F_OWNER flag which allows a userspace
program to own the table that creates in exclusivity.

Tables that are owned...

- can only be updated and removed by the owner, non-owners hit EPERM if
they try to update it or remove it.
- are destroyed when the owner closes the netlink socket or the process
is gone (implicit netlink socket closure).
- are skipped by the global flush ruleset command.
- are listed in the global ruleset.

The userspace process that sets on the NFT_TABLE_F_OWNER flag need to
leave open the netlink socket.

A new NFTA_TABLE_OWNER netlink attribute specifies the netlink port ID
to identify the owner from userspace.

This patch also updates error reporting when an unknown table flag is
specified to change it from EINVAL to EOPNOTSUPP given that EINVAL is
usually reserved to report for malformed netlink messages to userspace.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add helper function to release hooks of one single table

Add a function to release the hooks of one single table.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add helper function to release one table

Add a function to release one table.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: statify nft_parse_register()

This function is not used anymore by any extension, statify it.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add nft_parse_register_store() and use it

This new function combines the netlink register attribute parser
and the store validation function.

This update requires to replace:

enum nft_registers dreg:8;

in many of the expression private areas otherwise compiler complains
with:

error: cannot take address of bit-field ‘dreg’

when passing the register field as reference.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add nft_parse_register_load() and use it

This new function combines the netlink register attribute parser
and the load validation function.

This update requires to replace:

enum nft_registers sreg:8;

in many of the expression private areas otherwise compiler complains
with:

error: cannot take address of bit-field ‘sreg’

when passing the register field as reference.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: relax check for stateful expressions in set definition

Restore the original behaviour where users are allowed to add an element
with any stateful expression if the set definition specifies no stateful
expressions. Make sure upper maximum number of stateful expressions of
NFT_SET_EXPR_MAX is not reached.

Fixes: 8cfd9b0f8515 ("netfilter: nftables: generalize set expressions support")
Fixes: 48b0ae046ee9 ("netfilter: nftables: netlink support for several set element expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: fix possible UAF over chains from packet path in netns

Although hooks are released via call_rcu(), chain and rule objects are
immediately released while packets are still walking over these bits.

This patch adds the .pre_exit callback which is invoked before
synchronize_rcu() in the netns framework to stay safe.

Remove a comment which is not valid anymore since the core does not use
synchronize_net() anymore since 8c873e219970 ("netfilter: core: free
hooks with call_rcu").

Suggested-by: Florian Westphal <fw@strlen.de>
Fixes: df05ef874b28 ("netfilter: nf_tables: release objects on netns destruction")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_dynset: honor stateful expressions in set definition

If the set definition contains stateful expressions, allocate them for
the newly added entries from the packet path.

Fixes: 65038428b2c6 ("netfilter: nf_tables: allow to specify stateful expression in set definition")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: add set expression flags

The set flag NFT_SET_EXPR provides a hint to the kernel that userspace
supports for multiple expressions per set element. In the same
direction, NFT_DYNSET_F_EXPR specifies that dynset expression defines
multiple expressions per set element.

This allows new userspace software with old kernels to bail out with
EOPNOTSUPP. This update is similar to ef516e8625dd ("netfilter:
nf_tables: reintroduce the NFT_SET_CONCAT flag"). The NFT_SET_EXPR flag
needs to be set on when the NFTA_SET_EXPRESSIONS attribute is specified.
The NFT_SET_EXPR flag is not set on with NFTA_SET_EXPR to retain
backward compatibility in old userspace binaries.

Fixes: 48b0ae046ee9 ("netfilter: nftables: netlink support for several set element expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nftables: fix incorrect increment of loop counter

The intention of the err_expr cleanup path is to iterate over the
allocated expr_array objects and free them, starting from i - 1 and
working down to the start of the array. Currently the loop counter
is being incremented instead of decremented and also the index i is
being used instead of k, repeatedly destroying the same expr_array
element. Fix this by decrementing k and using k as the index into
expr_array.

Addresses-Coverity: ("Infinite loop")
Fixes: 8cfd9b0f8515 ("netfilter: nftables: generalize set expressions support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>