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

KASAN: vmalloc-out-of-bounds Read in __nla_validate_parse
Status: fixed on 2020/07/20 08:03
Reported-by: syzbot+314cd606fbedf9d5d0b2@syzkaller.appspotmail.com
Fix commit: bf64ff4c2aac genetlink: get rid of family->attrbuf
First crash: 450d, last: 430d

Sample crash report:

netlink: 'syz-executor.0': attribute type 2 has an invalid length.
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in nla_next include/net/netlink.h:1160 [inline]
BUG: KASAN: vmalloc-out-of-bounds in __nla_validate_parse+0x1ebc/0x21a0 lib/nlattr.c:521
Read of size 2 at addr ffffc90001bb9018 by task syz-executor.0/5009

CPU: 0 PID: 5009 Comm: syz-executor.0 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_next include/net/netlink.h:1160 [inline]
 __nla_validate_parse+0x1ebc/0x21a0 lib/nlattr.c:521
 __nla_parse+0x3d/0x4a lib/nlattr.c:630
 nla_parse_nested_deprecated include/net/netlink.h:1218 [inline]
 tipc_nl_publ_dump+0x239/0xce0 net/tipc/socket.c:3766
 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:00007f3bc1842c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000502440 RCX: 000000000045cb19
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a39 R14: 00000000004cd203 R15: 00007f3bc18436d4


Memory state around the buggy address:
 ffffc90001bb8f00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 ffffc90001bb8f80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
>ffffc90001bb9000: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
                            ^
 ffffc90001bb9080: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 ffffc90001bb9100: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
==================================================================

Crashes (7):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report
ci-upstream-bpf-kasan-gce	2020/06/28 23:00	bpf	7a64135f3229	a2cdad9d	.config	log	report
ci-upstream-bpf-kasan-gce	2020/06/24 00:48	bpf	4e15507fea70	54566aff	.config	log	report
ci-upstream-bpf-next-kasan-gce	2020/07/14 01:23	bpf-next	eef8a42d6ce0	f90ec899	.config	log	report
ci-upstream-bpf-next-kasan-gce	2020/07/12 20:10	bpf-next	eef8a42d6ce0	115e1930	.config	log	report
ci-upstream-bpf-next-kasan-gce	2020/07/11 06:33	bpf-next	eef8a42d6ce0	18d18b59	.config	log	report
ci-upstream-bpf-next-kasan-gce	2020/07/09 13:38	bpf-next	5cfd607b49db	bc238812	.config	log	report
ci-upstream-bpf-next-kasan-gce	2020/07/09 12:34	bpf-next	5cfd607b49db	bc238812	.config	log	report