CVE-2021-47106

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

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/

---truncated---