Re: KASAN: slab-out-of-bounds Read in hidraw_ioctl

[syzbot <syzbot+5a6c4ec678a0c6ee84ba@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer still triggered  
crash:
KASAN: slab-out-of-bounds Read in hidraw_ioctl

==================================================================
BUG: KASAN: slab-out-of-bounds in strnlen+0x75/0x80 lib/string.c:542
Read of size 1 at addr ffff8881d6a51f38 by task syz-executor.2/2785

CPU: 1 PID: 2785 Comm: syz-executor.2 Not tainted 5.3.0-rc2+ #1
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+0xca/0x13e lib/dump_stack.c:113
  print_address_description+0x6a/0x32c mm/kasan/report.c:351
  __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
  kasan_report+0xe/0x12 mm/kasan/common.c:612
  strnlen+0x75/0x80 lib/string.c:542
  strnlen include/linux/string.h:292 [inline]
  hidraw_ioctl+0x247/0xaa0 drivers/hid/hidraw.c:446
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:509 [inline]
  do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
  ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
  __do_sys_ioctl fs/ioctl.c:720 [inline]
  __se_sys_ioctl fs/ioctl.c:718 [inline]
  __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
  do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc7df1d0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000080404805 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc7df1d16d4
R13: 00000000004c21de R14: 00000000004d5620 R15: 00000000ffffffff

Allocated by task 2868:
  save_stack+0x1b/0x80 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  __kasan_kmalloc mm/kasan/common.c:487 [inline]
  __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460
  slab_post_alloc_hook mm/slab.h:520 [inline]
  slab_alloc_node mm/slub.c:2766 [inline]
  __kmalloc_node_track_caller+0xd0/0x230 mm/slub.c:4361
  __kmalloc_reserve.isra.0+0x39/0xe0 net/core/skbuff.c:141
  __alloc_skb+0xef/0x5a0 net/core/skbuff.c:209
  alloc_skb include/linux/skbuff.h:1055 [inline]
  alloc_uevent_skb+0x7b/0x210 lib/kobject_uevent.c:289
  uevent_net_broadcast_untagged lib/kobject_uevent.c:325 [inline]
  kobject_uevent_net_broadcast lib/kobject_uevent.c:408 [inline]
  kobject_uevent_env+0x8ee/0x1160 lib/kobject_uevent.c:592
  device_add+0xade/0x16f0 drivers/base/core.c:2113
  hid_add_device+0x33c/0x990 drivers/hid/hid-core.c:2365
  usbhid_probe+0xa81/0xfa0 drivers/hid/usbhid/hid-core.c:1386
  usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
  really_probe+0x281/0x650 drivers/base/dd.c:548
  driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
  bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
  __device_attach+0x217/0x360 drivers/base/dd.c:882
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
  device_add+0xae6/0x16f0 drivers/base/core.c:2114
  usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
  generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
  usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
  really_probe+0x281/0x650 drivers/base/dd.c:548
  driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
  bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
  __device_attach+0x217/0x360 drivers/base/dd.c:882
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
  device_add+0xae6/0x16f0 drivers/base/core.c:2114
  usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
  hub_port_connect drivers/usb/core/hub.c:5098 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
  port_event drivers/usb/core/hub.c:5359 [inline]
  hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
  process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
  worker_thread+0x96/0xe20 kernel/workqueue.c:2415
  kthread+0x318/0x420 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 238:
  save_stack+0x1b/0x80 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  __kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
  slab_free_hook mm/slub.c:1423 [inline]
  slab_free_freelist_hook mm/slub.c:1470 [inline]
  slab_free mm/slub.c:3012 [inline]
  kfree+0xe4/0x2f0 mm/slub.c:3953
  skb_free_head+0x8b/0xa0 net/core/skbuff.c:591
  skb_release_data+0x41f/0x7c0 net/core/skbuff.c:611
  skb_release_all+0x46/0x60 net/core/skbuff.c:665
  __kfree_skb net/core/skbuff.c:679 [inline]
  consume_skb net/core/skbuff.c:838 [inline]
  consume_skb+0xd9/0x320 net/core/skbuff.c:832
  skb_free_datagram+0x16/0xf0 net/core/datagram.c:328
  netlink_recvmsg+0x65e/0xee0 net/netlink/af_netlink.c:1996
  sock_recvmsg_nosec net/socket.c:871 [inline]
  sock_recvmsg net/socket.c:889 [inline]
  sock_recvmsg+0xca/0x110 net/socket.c:885
  ___sys_recvmsg+0x271/0x5a0 net/socket.c:2480
  __sys_recvmsg+0xe9/0x1b0 net/socket.c:2537
  do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881d6a51b00
  which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 56 bytes to the right of
  1024-byte region [ffff8881d6a51b00, ffff8881d6a51f00)
The buggy address belongs to the page:
page:ffffea00075a9400 refcount:1 mapcount:0 mapping:ffff8881da002280  
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da002280
raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8881d6a51e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d6a51e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881d6a51f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                         ^
  ffff8881d6a51f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d6a52000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1183deee600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1603c7c2600000