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

From: syzbot <[email-masked]>
Date: Mon, 22 Feb 2021 00:05:29 -0800

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: [email-masked]

================================================================================
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
================================================================================

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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