Message-ID: <CANn89iKLAOJ+HG_y7M27-tx+9HSLUyDaf_NtrJMjs2bZ52KZbA@mail.gmail.com>
Date: Sat, 9 Mar 2024 16:25:18 +0100
From: Eric Dumazet <edumazet@...gle.com>
To: syzbot <syzbot+65bb09a7208ce3d4a633@...kaller.appspotmail.com>, 
	Petr Machata <petrm@...dia.com>
Cc: davem@...emloft.net, dsahern@...nel.org, kuba@...nel.org, 
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org, pabeni@...hat.com, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [net?] kernel BUG in __nla_validate_parse

On Sat, Mar 9, 2024 at 4:13 PM syzbot
<syzbot+65bb09a7208ce3d4a633@...kaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    2f901582f032 Merge tag 'for-net-next-2024-03-08' of git://..
> git tree:       net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=112f130a180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=63afafeedf00ef8f
> dashboard link: https://syzkaller.appspot.com/bug?extid=65bb09a7208ce3d4a633
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/b03984cb5619/disk-2f901582.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/41787ac7c9d9/vmlinux-2f901582.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/da7931fd36f6/bzImage-2f901582.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+65bb09a7208ce3d4a633@...kaller.appspotmail.com
>
> ------------[ cut here ]------------
> kernel BUG at lib/nlattr.c:411!
> invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
> CPU: 1 PID: 14369 Comm: syz-executor.2 Not tainted 6.8.0-rc7-syzkaller-02415-g2f901582f032 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
> RIP: 0010:validate_nla lib/nlattr.c:411 [inline]
> RIP: 0010:__nla_validate_parse+0x2f61/0x2f70 lib/nlattr.c:635
> Code: 48 8b 4c 24 18 80 e1 07 38 c1 0f 8c e0 f7 ff ff 48 8b 7c 24 18 e8 ff 0e 1d fd e9 d1 f7 ff ff e8 d5 c2 91 06 e8 50 64 ba fc 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90
> RSP: 0018:ffffc90003c1eec0 EFLAGS: 00010287
> RAX: ffffffff84d90ad0 RBX: ffffffff8caa11b0 RCX: 0000000000040000
> RDX: ffffc9000499a000 RSI: 000000000000065e RDI: 000000000000065f
> RBP: ffffc90003c1f100 R08: ffffffff84d8df5b R09: 0000000000000000
> R10: ffffc90003c1f1a0 R11: fffff52000783e46 R12: 0000000000000008
> R13: 1ffff1100f9c4183 R14: 000000000000006e R15: 0000000000000005
> FS:  00007f5fe2d916c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020000440 CR3: 00000000229a2000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  __nla_parse+0x40/0x60 lib/nlattr.c:732
>  __nlmsg_parse include/net/netlink.h:756 [inline]
>  nlmsg_parse include/net/netlink.h:777 [inline]
>  rtm_del_nexthop+0x257/0x6d0 net/ipv4/nexthop.c:3256
>  rtnetlink_rcv_msg+0x89b/0x10d0 net/core/rtnetlink.c:6595
>  netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2556
>  netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
>  netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
>  netlink_sendmsg+0x8e0/0xcb0 net/netlink/af_netlink.c:1902
>  sock_sendmsg_nosec net/socket.c:730 [inline]
>  __sock_sendmsg+0x221/0x270 net/socket.c:745
>  ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
>  ___sys_sendmsg net/socket.c:2638 [inline]
>  __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
>  do_syscall_64+0xf9/0x240
>  entry_SYSCALL_64_after_hwframe+0x6f/0x77
> RIP: 0033:0x7f5fe207dda9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f5fe2d910c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f5fe21abf80 RCX: 00007f5fe207dda9
> RDX: 0000000000000000 RSI: 0000000020000440 RDI: 0000000000000003
> RBP: 00007f5fe20ca47a R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 000000000000000b R14: 00007f5fe21abf80 R15: 00007fff7d5a1278
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:validate_nla lib/nlattr.c:411 [inline]
> RIP: 0010:__nla_validate_parse+0x2f61/0x2f70 lib/nlattr.c:635
> Code: 48 8b 4c 24 18 80 e1 07 38 c1 0f 8c e0 f7 ff ff 48 8b 7c 24 18 e8 ff 0e 1d fd e9 d1 f7 ff ff e8 d5 c2 91 06 e8 50 64 ba fc 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90
> RSP: 0018:ffffc90003c1eec0 EFLAGS: 00010287
> RAX: ffffffff84d90ad0 RBX: ffffffff8caa11b0 RCX: 0000000000040000
> RDX: ffffc9000499a000 RSI: 000000000000065e RDI: 000000000000065f
> RBP: ffffc90003c1f100 R08: ffffffff84d8df5b R09: 0000000000000000
> R10: ffffc90003c1f1a0 R11: fffff52000783e46 R12: 0000000000000008
> R13: 1ffff1100f9c4183 R14: 000000000000006e R15: 0000000000000005
> FS:  00007f5fe2d916c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000c00104bb94 CR3: 00000000229a2000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want to overwrite report's subsystems, reply with:
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> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup

Petr, can you take a look ?

Thanks !


commit 2118f9390d83cf942de8b34faf3d35b54f9f4eee
Author: Petr Machata <petrm@...dia.com>
Date:   Wed Mar 6 13:49:15 2024 +0100

    net: nexthop: Adjust netlink policy parsing for a new attribute

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