syzbot


KMSAN: use-after-free in veth_xmit

Status: fixed on 2020/04/15 17:19
Subsystems: net
[Documentation on labels]
Fix commit: e08ad80551b4 net-backports: net: add strict checks in netdev_name_node_alt_destroy()
First crash: 1575d, last: 1560d

Sample crash report:
=====================================================
BUG: KMSAN: use-after-free in veth_xmit+0x2da/0xb70 drivers/net/veth.c:254
CPU: 1 PID: 932 Comm: kworker/u4:19 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 veth_xmit+0x2da/0xb70 drivers/net/veth.c:254
 __netdev_start_xmit include/linux/netdevice.h:4524 [inline]
 netdev_start_xmit include/linux/netdevice.h:4538 [inline]
 xmit_one net/core/dev.c:3470 [inline]
 dev_hard_start_xmit+0x531/0xab0 net/core/dev.c:3486
 __dev_queue_xmit+0x37de/0x4220 net/core/dev.c:4063
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4096
 batadv_send_skb_packet+0x59b/0x8c0 net/batman-adv/send.c:108
 batadv_send_broadcast_skb+0x76/0x90 net/batman-adv/send.c:127
 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:393 [inline]
 batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:419 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x97e/0xd50 net/batman-adv/bat_iv_ogm.c:1706
 process_one_work+0x1555/0x1f40 kernel/workqueue.c:2264
 worker_thread+0xef6/0x2450 kernel/workqueue.c:2410
 kthread+0x4b5/0x4f0 kernel/kthread.c:256
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:353

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_free+0x6e/0xb0 mm/kmsan/kmsan_hooks.c:107
 slab_free_freelist_hook mm/slub.c:1477 [inline]
 slab_free mm/slub.c:3040 [inline]
 kfree+0x565/0x30a0 mm/slub.c:3993
 __netdev_name_node_alt_destroy net/core/dev.c:322 [inline]
 netdev_name_node_alt_destroy+0x587/0x690 net/core/dev.c:334
 rtnl_alt_ifname net/core/rtnetlink.c:3518 [inline]
 rtnl_linkprop+0x939/0xc00 net/core/rtnetlink.c:3567
 rtnl_dellinkprop+0x9d/0xb0 net/core/rtnetlink.c:3588
 rtnetlink_rcv_msg+0x1153/0x1570 net/core/rtnetlink.c:5438
 netlink_rcv_skb+0x451/0x650 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5456
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0xf9e/0x1100 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x1246/0x14d0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343
 ___sys_sendmsg net/socket.c:2397 [inline]
 __sys_sendmsg+0x451/0x5f0 net/socket.c:2430
 __do_sys_sendmsg net/socket.c:2439 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2437
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2437
 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
=====================================================

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/03/16 05:32 https://github.com/google/kmsan.git master 8bbbc5cf3dca 749688d2 .config console log report ci-upstream-kmsan-gce
2020/03/16 05:31 https://github.com/google/kmsan.git master 8bbbc5cf3dca 749688d2 .config console log report ci-upstream-kmsan-gce
2020/03/10 16:51 https://github.com/google/kmsan.git master 8bbbc5cf3dca 35f53e45 .config console log report ci-upstream-kmsan-gce
2020/03/07 16:53 https://github.com/google/kmsan.git master 8bbbc5cf3dca 2e9971bb .config console log report ci-upstream-kmsan-gce
2020/03/01 13:22 https://github.com/google/kmsan.git master 8bbbc5cf3dca c88c7b75 .config console log report ci-upstream-kmsan-gce
2020/02/29 22:21 https://github.com/google/kmsan.git master 8bbbc5cf3dca 59b57593 .config console log report ci-upstream-kmsan-gce
2020/03/16 05:36 https://github.com/google/kmsan.git master 8bbbc5cf3dca 749688d2 .config console log report ci-upstream-kmsan-gce-386
2020/03/05 08:34 https://github.com/google/kmsan.git master 8bbbc5cf3dca c88c7b75 .config console log report ci-upstream-kmsan-gce-386
* Struck through repros no longer work on HEAD.