Re: [syzbot] [bridge?] [netfilter?] KASAN: vmalloc-out-of-bounds Read in __ebt_unregister_table

From: syzbot
Date: Sat Feb 18 2023 - 09:06:27 EST


Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: vmalloc-out-of-bounds Read in __ebt_unregister_table

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xf43/0xfc0 net/bridge/netfilter/ebtables.c:1178
Read of size 4 at addr ffffc90003263000 by task kworker/u4:6/3167

CPU: 0 PID: 3167 Comm: kworker/u4:6 Not tainted 6.2.0-rc8-syzkaller-00083-g3ac88fa4605e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
Workqueue: netns cleanup_net
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:306 [inline]
print_report+0x15e/0x45d mm/kasan/report.c:417
kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
__ebt_unregister_table+0xf43/0xfc0 net/bridge/netfilter/ebtables.c:1178
ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1382
ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169
cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613
process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
worker_thread+0x669/0x1090 kernel/workqueue.c:2436
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>

Memory state around the buggy address:
ffffc90003262f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90003262f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90003263000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
ffffc90003263080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90003263100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================


Tested on:

commit: 3ac88fa4 Merge tag 'net-6.2-final' of git://git.kernel..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12fc4f6f480000
kernel config: https://syzkaller.appspot.com/x/.config?x=fe56f7d193926860
dashboard link: https://syzkaller.appspot.com/bug?extid=f61594de72d6705aea03
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=173470f0c80000