KASAN: vmalloc-out-of-bounds Read in __cfg8NUM_wpan_dev_from_attrs

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 7a64135f libbpf: Adjust SEC short cut for expected attach ..
git tree: bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1365a5c5100000
kernel config: https://syzkaller.appspot.com/x/.config?x=dcc6334acae363d4
dashboard link: https://syzkaller.appspot.com/bug?extid=b108a9b0cf438a20f4f8
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b108a9...@syzkaller.appspotmail.com

netlink: 26 bytes leftover after parsing attributes in process `syz-executor.5'.
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in nla_get_u32 include/net/netlink.h:1541 [inline]
BUG: KASAN: vmalloc-out-of-bounds in __cfg802154_wpan_dev_from_attrs+0x4b4/0x510 net/ieee802154/nl802154.c:53
Read of size 4 at addr ffffc90001ad9018 by task syz-executor.5/31529

CPU: 1 PID: 31529 Comm: syz-executor.5 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
nla_get_u32 include/net/netlink.h:1541 [inline]
__cfg802154_wpan_dev_from_attrs+0x4b4/0x510 net/ieee802154/nl802154.c:53
nl802154_prepare_wpan_dev_dump.constprop.0+0xf9/0x490 net/ieee802154/nl802154.c:245
nl802154_dump_llsec_dev+0xc0/0xb10 net/ieee802154/nl802154.c:1655
genl_lock_dumpit+0x7f/0xb0 net/netlink/genetlink.c:575
netlink_dump+0x4cd/0xf60 net/netlink/af_netlink.c:2245
__netlink_dump_start+0x643/0x900 net/netlink/af_netlink.c:2353
genl_family_rcv_msg_dumpit+0x2ac/0x310 net/netlink/genetlink.c:638
genl_family_rcv_msg net/netlink/genetlink.c:733 [inline]
genl_rcv_msg+0x797/0x9e0 net/netlink/genetlink.c:753
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469
genl_rcv+0x24/0x40 net/netlink/genetlink.c:764
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
____sys_sendmsg+0x6e8/0x810 net/socket.c:2352
___sys_sendmsg+0xf3/0x170 net/socket.c:2406
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb19
Code: Bad RIP value.
RSP: 002b:00007ff9558abc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000502400 RCX: 000000000045cb19
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a38 R14: 00000000004cd1fc R15: 00007ff9558ac6d4


Memory state around the buggy address:
ffffc90001ad8f00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
ffffc90001ad8f80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
>ffffc90001ad9000: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
^
ffffc90001ad9080: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
ffffc90001ad9100: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
==================================================================


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[Cong Wang]

#syz fix: genetlink: get rid of family->attrbuf