CVE-2024-35899

In the Linux kernel, the following vulnerability has been resolved:

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_deactivat

---truncated---