syzbot


KASAN: use-after-free Read in __vxlan_dev_create

Status: auto-closed as invalid on 2020/11/30 05:13
Reported-by: syzbot+950e3c4e4803fdb41345@syzkaller.appspotmail.com
First crash: 745d, last: 745d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 KASAN: use-after-free Read in __vxlan_dev_create 1 689d 689d 0/1 auto-closed as invalid on 2021/01/24 23:00

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:676 [inline]
BUG: KASAN: use-after-free in hlist_del_rcu include/linux/rculist.h:457 [inline]
BUG: KASAN: use-after-free in vxlan_fdb_destroy drivers/net/vxlan.c:788 [inline]
BUG: KASAN: use-after-free in __vxlan_dev_create+0xa32/0xad0 drivers/net/vxlan.c:3270
Read of size 8 at addr ffff888094796d00 by task syz-executor.3/524

CPU: 1 PID: 524 Comm: syz-executor.3 Not tainted 4.19.136-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+0x1fc/0x2fe lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 __hlist_del include/linux/list.h:676 [inline]
 hlist_del_rcu include/linux/rculist.h:457 [inline]
 vxlan_fdb_destroy drivers/net/vxlan.c:788 [inline]
 __vxlan_dev_create+0xa32/0xad0 drivers/net/vxlan.c:3270
 vxlan_newlink+0xc0/0x120 drivers/net/vxlan.c:3497
 rtnl_newlink+0x1027/0x15b0 net/core/rtnetlink.c:3141
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4778
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2455
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6bb/0xc40 net/netlink/af_netlink.c:1909
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:632
 sock_no_sendpage+0xf5/0x140 net/core/sock.c:2647
 kernel_sendpage net/socket.c:3378 [inline]
 sock_sendpage+0xdf/0x140 net/socket.c:847
 pipe_to_sendpage+0x268/0x330 fs/splice.c:452
 splice_from_pipe_feed fs/splice.c:503 [inline]
 __splice_from_pipe+0x389/0x800 fs/splice.c:627
 splice_from_pipe fs/splice.c:662 [inline]
 generic_splice_sendpage+0xd4/0x140 fs/splice.c:833
 do_splice_from fs/splice.c:852 [inline]
 do_splice fs/splice.c:1154 [inline]
 __do_sys_splice fs/splice.c:1428 [inline]
 __se_sys_splice+0xfe7/0x16d0 fs/splice.c:1408
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cc79
Code: 2d 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2b1074fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 0000000000032b80 RCX: 000000000045cc79
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000078bff8 R08: 000000000004ffe2 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac
R13: 00007ffcbb21799f R14: 00007f2b107509c0 R15: 000000000078bfac

Allocated by task 524:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 vxlan_fdb_alloc drivers/net/vxlan.c:646 [inline]
 vxlan_fdb_create+0x153/0x630 drivers/net/vxlan.c:674
 __vxlan_dev_create+0x42d/0xad0 drivers/net/vxlan.c:3236
 vxlan_newlink+0xc0/0x120 drivers/net/vxlan.c:3497
 rtnl_newlink+0x1027/0x15b0 net/core/rtnetlink.c:3141
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4778
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2455
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6bb/0xc40 net/netlink/af_netlink.c:1909
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:632
 sock_no_sendpage+0xf5/0x140 net/core/sock.c:2647
 kernel_sendpage net/socket.c:3378 [inline]
 sock_sendpage+0xdf/0x140 net/socket.c:847
 pipe_to_sendpage+0x268/0x330 fs/splice.c:452
 splice_from_pipe_feed fs/splice.c:503 [inline]
 __splice_from_pipe+0x389/0x800 fs/splice.c:627
 splice_from_pipe fs/splice.c:662 [inline]
 generic_splice_sendpage+0xd4/0x140 fs/splice.c:833
 do_splice_from fs/splice.c:852 [inline]
 do_splice fs/splice.c:1154 [inline]
 __do_sys_splice fs/splice.c:1428 [inline]
 __se_sys_splice+0xfe7/0x16d0 fs/splice.c:1408
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 18:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 __rcu_reclaim kernel/rcu/rcu.h:236 [inline]
 rcu_do_batch kernel/rcu/tree.c:2584 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
 rcu_process_callbacks+0x8ff/0x18b0 kernel/rcu/tree.c:2881
 __do_softirq+0x26c/0x9a0 kernel/softirq.c:292

The buggy address belongs to the object at ffff888094796d00
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
 96-byte region [ffff888094796d00, ffff888094796d60)
The buggy address belongs to the page:
page:ffffea000251e580 count:1 mapcount:0 mapping:ffff88812c39c4c0 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea00027c9648 ffffea0002a56008 ffff88812c39c4c0
raw: 0000000000000000 ffff888094796000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888094796c00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff888094796c80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
>ffff888094796d00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                   ^
 ffff888094796d80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
 ffff888094796e00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
==================================================================
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=1545 sclass=netlink_route_socket pid=555 comm=syz-executor.3
netlink: 52 bytes leftover after parsing attributes in process `syz-executor.3'.

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2020/08/02 05:12 linux-4.19.y 13af6c74b14a 8df85ed9 .config log report