[syzbot] [netfilter?] KASAN: slab-use-after-free Read in nf_tables_trans_destroy_work

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1c5fc27bc48a Merge tag 'nf-next-24-06-28' of git://git.ker..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=103b1da9980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5264b58fdff6e881
dashboard link: https://syzkaller.appspot.com/bug?extid=4fd66a69358fc15ae2ad
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148791c6980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12cecb1e980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9672225af907/disk-1c5fc27b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0f14d163a914/vmlinux-1c5fc27b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ec6c331e6a6e/bzImage-1c5fc27b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4fd66a...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline]
BUG: KASAN: slab-use-after-free in nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline]
BUG: KASAN: slab-use-after-free in nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597
Read of size 2 at addr ffff88802b0051c4 by task kworker/1:1/45

CPU: 1 PID: 45 Comm: kworker/1:1 Not tainted 6.10.0-rc5-syzkaller-01137-g1c5fc27bc48a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: events nf_tables_trans_destroy_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline]
nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline]
nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597
process_one_work kernel/workqueue.c:3248 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Allocated by task 6682:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
kmalloc_trace_noprof+0x19c/0x2c0 mm/slub.c:4154
kmalloc_noprof include/linux/slab.h:660 [inline]
kzalloc_noprof include/linux/slab.h:778 [inline]
nf_tables_newtable+0x52e/0x1dc0 net/netfilter/nf_tables_api.c:1465
nfnetlink_rcv_batch net/netfilter/nfnetlink.c:522 [inline]
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:644 [inline]
nfnetlink_rcv+0x1427/0x2a90 net/netfilter/nfnetlink.c:662
netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357
netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2585
___sys_sendmsg net/socket.c:2639 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6682:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
__kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2196 [inline]
slab_free mm/slub.c:4438 [inline]
kfree+0x149/0x360 mm/slub.c:4559
nf_tables_table_destroy net/netfilter/nf_tables_api.c:1672 [inline]
__nft_release_table+0xe80/0xf40 net/netfilter/nf_tables_api.c:11517
nft_rcv_nl_event+0x55f/0x6d0 net/netfilter/nf_tables_api.c:11576
notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
blocking_notifier_call_chain+0x69/0x90 kernel/notifier.c:388
netlink_release+0x11a6/0x1b10 net/netlink/af_netlink.c:787
__sock_release net/socket.c:659 [inline]
sock_close+0xbc/0x240 net/socket.c:1421
__fput+0x406/0x8b0 fs/file_table.c:422
task_work_run+0x24f/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa27/0x27e0 kernel/exit.c:874
do_group_exit+0x207/0x2c0 kernel/exit.c:1023
__do_sys_exit_group kernel/exit.c:1034 [inline]
__se_sys_exit_group kernel/exit.c:1032 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1032
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
insert_work+0x3e/0x330 kernel/workqueue.c:2208
__queue_work+0xc16/0xee0 kernel/workqueue.c:2360
queue_work_on+0x1c2/0x380 kernel/workqueue.c:2411
queue_work include/linux/workqueue.h:621 [inline]
schedule_work include/linux/workqueue.h:682 [inline]
__rhashtable_remove_fast_one include/linux/rhashtable.h:1069 [inline]
__rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
rhltable_remove+0x1097/0x1160 include/linux/rhashtable.h:1144
nft_chain_del net/netfilter/nf_tables_api.c:9781 [inline]
__nft_release_table+0xc57/0xf40 net/netfilter/nf_tables_api.c:11513
nft_rcv_nl_event+0x55f/0x6d0 net/netfilter/nf_tables_api.c:11576
notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
blocking_notifier_call_chain+0x69/0x90 kernel/notifier.c:388
netlink_release+0x11a6/0x1b10 net/netlink/af_netlink.c:787
__sock_release net/socket.c:659 [inline]
sock_close+0xbc/0x240 net/socket.c:1421
__fput+0x406/0x8b0 fs/file_table.c:422
task_work_run+0x24f/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa27/0x27e0 kernel/exit.c:874
do_group_exit+0x207/0x2c0 kernel/exit.c:1023
__do_sys_exit_group kernel/exit.c:1034 [inline]
__se_sys_exit_group kernel/exit.c:1032 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1032
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802b005000
which belongs to the cache kmalloc-cg-512 of size 512
The buggy address is located 452 bytes inside of
freed 512-byte region [ffff88802b005000, ffff88802b005200)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b004
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000040 ffff88801504f140 ffffea0000b63700 0000000000000002
raw: 0000000000000000 0000000080100010 00000001ffffefff 0000000000000000
head: 00fff00000000040 ffff88801504f140 ffffea0000b63700 0000000000000002
head: 0000000000000000 0000000080100010 00000001ffffefff 0000000000000000
head: 00fff00000000002 ffffea0000ac0101 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4764, tgid 4764 (dhcpcd), ts 34584428687, free_ts 34557820760
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1473
prep_new_page mm/page_alloc.c:1481 [inline]
get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3425
__alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4683
__alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
alloc_slab_page+0x5f/0x120 mm/slub.c:2265
allocate_slab+0x5a/0x2f0 mm/slub.c:2428
new_slab mm/slub.c:2481 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3667
__slab_alloc+0x58/0xa0 mm/slub.c:3757
__slab_alloc_node mm/slub.c:3810 [inline]
slab_alloc_node mm/slub.c:3990 [inline]
__do_kmalloc_node mm/slub.c:4122 [inline]
kmalloc_node_track_caller_noprof+0x281/0x440 mm/slub.c:4143
kmalloc_reserve+0x111/0x2a0 net/core/skbuff.c:605
__alloc_skb+0x1f3/0x440 net/core/skbuff.c:674
alloc_skb include/linux/skbuff.h:1320 [inline]
alloc_skb_with_frags+0xc3/0x770 net/core/skbuff.c:6524
sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2815
unix_dgram_sendmsg+0x6d3/0x1f80 net/unix/af_unix.c:2030
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
__sys_sendto+0x3a4/0x4f0 net/socket.c:2192
__do_sys_sendto net/socket.c:2204 [inline]
__se_sys_sendto net/socket.c:2200 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2200
page last free pid 4764 tgid 4764 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1093 [inline]
free_unref_page+0xd22/0xea0 mm/page_alloc.c:2588
stack_depot_save_flags+0x6f6/0x830 lib/stackdepot.c:666
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_save_track+0x51/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:312 [inline]
__kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3940 [inline]
slab_alloc_node mm/slub.c:4002 [inline]
kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4045
kmalloc_reserve+0xa8/0x2a0 net/core/skbuff.c:583
__alloc_skb+0x1f3/0x440 net/core/skbuff.c:674
alloc_skb include/linux/skbuff.h:1320 [inline]
__ip6_append_data+0x2ba6/0x4070 net/ipv6/ip6_output.c:1648
ip6_append_data+0x264/0x3a0 net/ipv6/ip6_output.c:1835
rawv6_sendmsg+0x18f1/0x23c0 net/ipv6/raw.c:919
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x1a6/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2585
___sys_sendmsg net/socket.c:2639 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff88802b005080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802b005100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802b005180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802b005200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802b005280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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If the report is already addressed, let syzbot know by replying with:
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If you want to undo deduplication, reply with:
#syz undup

[Florian Westphal]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/fwestphal/nf-next.git flush_uncond

[Hillf Danton]

On Mon, 01 Jul 2024 13:19:15 -0700

> syzbot found the following issue on:
>
> HEAD commit: 1c5fc27bc48a Merge tag 'nf-next-24-06-28' of git://git.ker..
> git tree: net-next

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12cecb1e980000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 1c5fc27bc48a

--- x/include/net/netfilter/nf_tables.h
+++ y/include/net/netfilter/nf_tables.h
@@ -1281,6 +1281,7 @@ struct nft_table {
u64 hgenerator;
u64 handle;
u32 use;
+ atomic_t cnt;
u16 family:6,
flags:8,
genmask:2;
--- x/net/netfilter/nf_tables_api.c
+++ y/net/netfilter/nf_tables_api.c
@@ -162,6 +162,8 @@ static struct nft_trans *nft_trans_alloc

trans->net = ctx->net;
trans->table = ctx->table;
+ if (trans->table)
+ atomic_inc(&trans->table->cnt);
trans->seq = ctx->seq;
trans->flags = ctx->flags;
trans->report = ctx->report;
@@ -1498,6 +1500,7 @@ static int nf_tables_newtable(struct sk_
if (err < 0)
goto err_trans;

+ atomic_inc(&table->cnt);
list_add_tail_rcu(&table->list, &nft_net->tables);
return 0;
err_trans:
@@ -1663,6 +1666,8 @@ static int nf_tables_deltable(struct sk_

static void nf_tables_table_destroy(struct nft_table *table)
{
+ if (!atomic_dec_and_test(&table->cnt))
+ return;
if (WARN_ON(table->use > 0))
return;

@@ -9532,7 +9537,6 @@ static void nft_commit_release(struct nf
switch (trans->msg_type) {
case NFT_MSG_DELTABLE:
case NFT_MSG_DESTROYTABLE:
- nf_tables_table_destroy(trans->table);
break;
case NFT_MSG_NEWCHAIN:
free_percpu(nft_trans_chain_stats(trans));
@@ -9572,6 +9576,9 @@ static void nft_commit_release(struct nf
break;
}

+ if (trans->table)
+ nf_tables_table_destroy(trans->table);
+
if (trans->put_net)
put_net(trans->net);

--