syzbot

audit: type=1400 audit(1596206090.429:8): avc:  denied  { execmem } for  pid=6434 comm="syz-executor623" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
IPVS: ftp: loaded support on port[0] = 21
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:373 [inline]
BUG: KASAN: slab-out-of-bounds in bacpy include/net/bluetooth/bluetooth.h:236 [inline]
BUG: KASAN: slab-out-of-bounds in hci_inquiry_result_with_rssi_evt+0x225/0x6b0 net/bluetooth/hci_event.c:3951
Read of size 6 at addr ffff88808cbbe9bb by task kworker/u5:0/1228

CPU: 0 PID: 1228 Comm: kworker/u5:0 Not tainted 4.19.135-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
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+0x8f/0x96 mm/kasan/report.c:412
 memcpy+0x20/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:373 [inline]
 bacpy include/net/bluetooth/bluetooth.h:236 [inline]
 hci_inquiry_result_with_rssi_evt+0x225/0x6b0 net/bluetooth/hci_event.c:3951
 hci_event_packet+0x18a3/0x858f net/bluetooth/hci_event.c:5833
 hci_rx_work+0x46b/0xa90 net/bluetooth/hci_core.c:4359
 process_one_work+0x864/0x1570 kernel/workqueue.c:2155
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
 kthread+0x30b/0x410 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 6435:
 __do_kmalloc_node mm/slab.c:3689 [inline]
 __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703
 __kmalloc_reserve net/core/skbuff.c:137 [inline]
 __alloc_skb+0xae/0x560 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:995 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:180 [inline]
 vhci_write+0xbd/0x450 drivers/bluetooth/hci_vhci.c:299
 call_write_iter include/linux/fs.h:1821 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x51b/0x770 fs/read_write.c:487
 vfs_write+0x1f3/0x540 fs/read_write.c:549
 ksys_write+0x12b/0x2a0 fs/read_write.c:599
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4647:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 skb_free_head net/core/skbuff.c:554 [inline]
 skb_release_data+0x6de/0x920 net/core/skbuff.c:574
 skb_release_all net/core/skbuff.c:631 [inline]
 __kfree_skb net/core/skbuff.c:645 [inline]
 consume_skb+0x113/0x3d0 net/core/skbuff.c:705
 skb_free_datagram+0x16/0xf0 net/core/datagram.c:329
 netlink_recvmsg+0x627/0xea0 net/netlink/af_netlink.c:1988
 sock_recvmsg_nosec net/socket.c:795 [inline]
 sock_recvmsg net/socket.c:802 [inline]
 sock_recvmsg+0xca/0x110 net/socket.c:798
 ___sys_recvmsg+0x255/0x570 net/socket.c:2277
 __sys_recvmsg net/socket.c:2326 [inline]
 __do_sys_recvmsg net/socket.c:2336 [inline]
 __se_sys_recvmsg net/socket.c:2333 [inline]
 __x64_sys_recvmsg+0x12f/0x220 net/socket.c:2333
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808cbbe7c0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 507 bytes inside of
 512-byte region [ffff88808cbbe7c0, ffff88808cbbe9c0)
The buggy address belongs to the page:
page:ffffea000232ef80 count:1 mapcount:0 mapping:ffff88812c39c940 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea00022e7608 ffffea00022ee888 ffff88812c39c940
raw: 0000000000000000 ffff88808cbbe040 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808cbbe880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808cbbe900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808cbbe980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                           ^
 ffff88808cbbea00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff88808cbbea80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================