Subject: KASAN: vmalloc-out-of-bounds Read in tipc_nl_node_dump_monitor_peer

From: syzbot <[email-masked]>
Date: Tue, 23 Jun 2020 09:56:19 -0700

Hello,

syzbot found the following crash on:

HEAD commit:    4e15507f libbpf: Forward-declare bpf_stats_type for system..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1227a0ad100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dcc6334acae363d4
dashboard link: https://syzkaller.appspot.com/bug?extid=80cad1e3cb4c41cde6ff
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=155fef15100000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=127acae9100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in nla_len include/net/netlink.h:1135 [inline]
BUG: KASAN: vmalloc-out-of-bounds in nla_parse_nested_deprecated include/net/netlink.h:1218 [inline]
BUG: KASAN: vmalloc-out-of-bounds in tipc_nl_node_dump_monitor_peer+0x4da/0x590 net/tipc/node.c:2788
Read of size 2 at addr ffffc90004959024 by task syz-executor857/7189

CPU: 1 PID: 7189 Comm: syz-executor857 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_len include/net/netlink.h:1135 [inline]
 nla_parse_nested_deprecated include/net/netlink.h:1218 [inline]
 tipc_nl_node_dump_monitor_peer+0x4da/0x590 net/tipc/node.c:2788
 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: 0033:0x446859
Code: Bad RIP value.
RSP: 002b:00007f102ce25d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 0000000000446859
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
R13: 4002001060fc2413 R14: 0d94638c64805ad2 R15: 0f05002d0000022e

Memory state around the buggy address:
 ffffc90004958f00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 ffffc90004958f80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
>ffffc90004959000: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
                               ^
 ffffc90004959080: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 ffffc90004959100: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
==================================================================

---
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