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

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Message-ID: <0000000000000dfa9605f5088119@google.com>
Date:   Sat, 18 Feb 2023 23:29:17 -0800
From:   syzbot <syzbot+f61594de72d6705aea03@...kaller.appspotmail.com>
To:     hdanton@...a.com, linux-kernel@...r.kernel.org,
        syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bridge?] [netfilter?] KASAN: vmalloc-out-of-bounds Read
 in __ebt_unregister_table

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+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1175
Read of size 4 at addr ffffc90003755000 by task kworker/u4:2/41

CPU: 0 PID: 41 Comm: kworker/u4:2 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+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1175
 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1383
 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:
 ffffc90003754f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90003754f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90003755000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90003755080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90003755100: 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=15693b58c80000
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=11afbd80c80000