WARNING in nft_request_module

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: db5b9190 Linux 4.19.96
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1190f021e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=7a24894346f71303
dashboard link: https://syzkaller.appspot.com/bug?extid=a82da32a445c2f555290
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e55d8ee00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141318d1e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a82da3...@syzkaller.appspotmail.com

audit: type=1400 audit(1579144984.007:38): avc: denied { write } for
pid=8241 comm="syz-executor192"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tclass=netlink_netfilter_socket permissive=1
------------[ cut here ]------------
truncated: 'nft-expr-0-���LMMR�~� �*�{ ���F�� �� Dc� �H�c ( ��?V �' (len
209)
WARNING: CPU: 1 PID: 8241 at net/netfilter/nf_tables_api.c:507
nft_request_module+0x189/0x1a0 net/netfilter/nf_tables_api.c:507
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 8241 Comm: syz-executor192 Not tainted 4.19.96-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
panic+0x26a/0x50e kernel/panic.c:186
__warn.cold+0x20/0x53 kernel/panic.c:541
report_bug+0x263/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x204/0x360 arch/x86/kernel/traps.c:296
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037
RIP: 0010:nft_request_module+0x189/0x1a0 net/netfilter/nf_tables_api.c:507
Code: 00 75 2b 48 81 c4 10 01 00 00 5b 41 5c 41 5d 5d c3 e8 7b 85 6a fb 44
89 ea 48 c7 c7 60 18 50 88 48 8d 74 24 60 e8 e5 14 3e fb <0f> 0b eb 9a e8
9e 0d 3e fb 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00
RSP: 0018:ffff88808ef87278 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff89a03040 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81558bc6 RDI: ffffed1011df0e41
RBP: ffff88808ef873a0 R08: ffff8880824b6500 R09: ffff8880824b6da0
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff11011df0e4f
R13: 00000000000000d1 R14: 0000000000000000 R15: ffff88808ef87450
nft_expr_type_get net/netfilter/nf_tables_api.c:2000 [inline]
nf_tables_expr_parse+0x46d/0x5e0 net/netfilter/nf_tables_api.c:2075
nf_tables_newrule+0x73f/0x2140 net/netfilter/nf_tables_api.c:2641
nfnetlink_rcv_batch+0xef6/0x1750 net/netfilter/nfnetlink.c:430
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:540 [inline]
nfnetlink_rcv+0x3ed/0x460 net/netfilter/nfnetlink.c:558
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x53a/0x730 net/netlink/af_netlink.c:1343
netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1908
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:632
___sys_sendmsg+0x803/0x920 net/socket.c:2115
__sys_sendmsg+0x105/0x1d0 net/socket.c:2153
__do_sys_sendmsg net/socket.c:2162 [inline]
__se_sys_sendmsg net/socket.c:2160 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2160
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440619
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe2bf553b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440619
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000005
RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401ea0
R13: 0000000000401f30 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[syzbot]

syzbot suspects this bug was fixed by commit:

commit 1632efb3553b7e79ffc666ff5291705b4b87eb6c
Author: Florian Westphal <f...@strlen.de>
Date: Thu Jan 16 08:06:50 2020 +0000

netfilter: nf_tables: remove WARN and add NLA_STRING upper limits

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1362a579e00000
start commit: db5b9190 Linux 4.19.96
git tree: linux-4.19.y

kernel config: https://syzkaller.appspot.com/x/.config?x=7a24894346f71303
dashboard link: https://syzkaller.appspot.com/bug?extid=a82da32a445c2f555290

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e55d8ee00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141318d1e00000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: netfilter: nf_tables: remove WARN and add NLA_STRING upper limits

For information about bisection process see: https://goo.gl/tpsmEJ#bisection