syzbot


KMSAN: use-after-free in dev_alloc_name_ns

Status: fixed on 2020/04/15 17:19
Subsystems: net
[Documentation on labels]
Fix commit: e08ad80551b4 net: add strict checks in netdev_name_node_alt_destroy()
First crash: 1601d, last: 1587d

Sample crash report:
=====================================================
BUG: KMSAN: use-after-free in __dev_alloc_name net/core/dev.c:1110 [inline]
BUG: KMSAN: use-after-free in dev_alloc_name_ns+0xa5b/0xd50 net/core/dev.c:1145
CPU: 0 PID: 26875 Comm: syz-executor.1 Not tainted 5.6.0-rc2-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+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
 __dev_alloc_name net/core/dev.c:1110 [inline]
 dev_alloc_name_ns+0xa5b/0xd50 net/core/dev.c:1145
 dev_get_valid_name net/core/dev.c:1180 [inline]
 register_netdevice+0x593/0x31b0 net/core/dev.c:9299
 veth_newlink+0xae0/0x1430 drivers/net/veth.c:1285
 __rtnl_newlink net/core/rtnetlink.c:3319 [inline]
 rtnl_newlink+0x2973/0x3920 net/core/rtnetlink.c:3377
 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
RIP: 0033:0x45c849
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0b8ead2c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0b8ead36d4 RCX: 000000000045c849
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000007
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009f9 R14: 00000000004ccb17 R15: 000000000076bf0c

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 (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/03/16 05:43 https://github.com/google/kmsan.git master 8bbbc5cf3dca 749688d2 .config console log report ci-upstream-kmsan-gce
2020/03/02 10:54 https://github.com/google/kmsan.git master 8bbbc5cf3dca c88c7b75 .config console log report ci-upstream-kmsan-gce
2020/03/07 10:14 https://github.com/google/kmsan.git master 8bbbc5cf3dca fd2a5f28 .config console log report ci-upstream-kmsan-gce-386
* Struck through repros no longer work on HEAD.