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

2020-06-29 Thread Cong Wang
#syz fix: genetlink: get rid of family->attrbuf


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

2020-06-27 Thread 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=1365a5c510
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+b108a9b0cf438a20f...@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 c90001ad9018 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:7ff9558abc78 EFLAGS: 0246 ORIG_RAX: 002e
RAX: ffda RBX: 00502400 RCX: 0045cb19
RDX:  RSI: 2080 RDI: 0004
RBP: 0078bf00 R08:  R09: 
R10:  R11: 0246 R12: 
R13: 0a38 R14: 004cd1fc R15: 7ff9558ac6d4


Memory state around the buggy address:
 c90001ad8f00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 c90001ad8f80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
>c90001ad9000: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
^
 c90001ad9080: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 c90001ad9100: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
==


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