Re: UBSAN: shift-out-of-bounds in nl802154_new_interface

[Jakub Kicinski]

Alex, there seems to be a few more syzbot reports for nl802154 beyond
what you posted fixes for. Are you looking at these?

On Mon, 22 Feb 2021 00:05:29 -0800 syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    3af409ca net: enetc: fix destroyed phylink dereference dur..
> git tree:       net
> console output: https://syzkaller.appspot.com/x/log.txt?x=139da604d00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8cb23303ddb9411f
> dashboard link: https://syzkaller.appspot.com/bug?extid=7bf7b22759195c9a21e9
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=108c7e04d00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1177c324d00000
> 
> Bisection is inconclusive: the issue happens on the oldest tested release.
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11a6e7d2d00000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=13a6e7d2d00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=15a6e7d2d00000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+7bf7b22759195c9a21e9@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ================================================================================
> UBSAN: shift-out-of-bounds in net/ieee802154/nl802154.c:914:44
> shift exponent -1627389953 is negative
> CPU: 0 PID: 8454 Comm: syz-executor539 Not tainted 5.11.0-rc7-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:79 [inline]
>  dump_stack+0x107/0x163 lib/dump_stack.c:120
>  ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
>  __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:395
>  nl802154_new_interface.cold+0x19/0x1e net/ieee802154/nl802154.c:914
>  genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739
>  genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
>  genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800
>  netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
>  genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
>  netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
>  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
>  netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
>  sock_sendmsg_nosec net/socket.c:652 [inline]
>  sock_sendmsg+0xcf/0x120 net/socket.c:672
>  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345
>  ___sys_sendmsg+0xf3/0x170 net/socket.c:2399
>  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432
>  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x43fa19
> Code: 28 c3 e8 5a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fffda15b8b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00000000004004a0 RCX: 000000000043fa19
> RDX: 0000000000000000 RSI: 0000000020000ac0 RDI: 0000000000000003
> RBP: 0000000000403480 R08: 0000000000000001 R09: 00000000004004a0
> R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000403510
> R13: 0000000000000000 R14: 00000000004ad018 R15: 00000000004004a0
> ================================================================================
> 
> 
> ---
> 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@xxxxxxxxxxxxxxxx.
> 
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches