KASAN: slab-out-of-bounds Write in betop_probe

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: e5cd56e9 usb: gadget: add raw-gadget interface
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=1517fed9e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=8cff427cc8996115
dashboard link: https://syzkaller.appspot.com/bug?extid=07efed3bc5a1407bd742
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=147026b5e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1683b6b5e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+07efed...@syzkaller.appspotmail.com

betop 0003:20BC:5500.0001: unknown main item tag 0x0
betop 0003:20BC:5500.0001: hidraw0: USB HID v0.00 Device [HID 20bc:5500] on usb-dummy_hcd.0-1/input0
==================================================================
BUG: KASAN: slab-out-of-bounds in set_bit include/asm-generic/bitops/instrumented-atomic.h:28 [inline]
BUG: KASAN: slab-out-of-bounds in betopff_init drivers/hid/hid-betopff.c:99 [inline]
BUG: KASAN: slab-out-of-bounds in betop_probe+0x396/0x570 drivers/hid/hid-betopff.c:134
Write of size 8 at addr ffff8881d4f43ac0 by task kworker/1:2/94

CPU: 1 PID: 94 Comm: kworker/1:2 Not tainted 5.5.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xef/0x16e lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:374
__kasan_report.cold+0x37/0x77 mm/kasan/report.c:506
kasan_report+0xe/0x20 mm/kasan/common.c:641
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x152/0x1c0 mm/kasan/generic.c:192
set_bit include/asm-generic/bitops/instrumented-atomic.h:28 [inline]
betopff_init drivers/hid/hid-betopff.c:99 [inline]
betop_probe+0x396/0x570 drivers/hid/hid-betopff.c:134
hid_device_probe+0x2be/0x3f0 drivers/hid/hid-core.c:2261
really_probe+0x290/0xac0 drivers/base/dd.c:551
driver_probe_device+0x223/0x350 drivers/base/dd.c:724
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:831
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
__device_attach+0x217/0x390 drivers/base/dd.c:897
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0x1459/0x1bf0 drivers/base/core.c:2487
hid_add_device drivers/hid/hid-core.c:2417 [inline]
hid_add_device+0x33c/0x9a0 drivers/hid/hid-core.c:2366
usbhid_probe+0xa81/0xfa0 drivers/hid/usbhid/hid-core.c:1386
usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:361
really_probe+0x290/0xac0 drivers/base/dd.c:551
driver_probe_device+0x223/0x350 drivers/base/dd.c:724
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:831
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
__device_attach+0x217/0x390 drivers/base/dd.c:897
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0x1459/0x1bf0 drivers/base/core.c:2487
usb_set_configuration+0xe47/0x17d0 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0xaf/0x140 drivers/usb/core/driver.c:266
really_probe+0x290/0xac0 drivers/base/dd.c:551
driver_probe_device+0x223/0x350 drivers/base/dd.c:724
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:831
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
__device_attach+0x217/0x390 drivers/base/dd.c:897
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0x1459/0x1bf0 drivers/base/core.c:2487
usb_new_device.cold+0x540/0xcd0 drivers/usb/core/hub.c:2538
hub_port_connect drivers/usb/core/hub.c:5185 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5325 [inline]
port_event drivers/usb/core/hub.c:5471 [inline]
hub_event+0x21cb/0x4300 drivers/usb/core/hub.c:5553
process_one_work+0x94b/0x1620 kernel/workqueue.c:2264
worker_thread+0x96/0xe20 kernel/workqueue.c:2410
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 94:
save_stack+0x1b/0x80 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc mm/kasan/common.c:515 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:488
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:670 [inline]
hidraw_connect+0x4b/0x3e0 drivers/hid/hidraw.c:521
hid_connect+0x5c7/0xbb0 drivers/hid/hid-core.c:1937
hid_hw_start drivers/hid/hid-core.c:2033 [inline]
hid_hw_start+0xa2/0x130 drivers/hid/hid-core.c:2024
betop_probe+0xbc/0x570 drivers/hid/hid-betopff.c:128
hid_device_probe+0x2be/0x3f0 drivers/hid/hid-core.c:2261
really_probe+0x290/0xac0 drivers/base/dd.c:551
driver_probe_device+0x223/0x350 drivers/base/dd.c:724
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:831
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
__device_attach+0x217/0x390 drivers/base/dd.c:897
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0x1459/0x1bf0 drivers/base/core.c:2487
hid_add_device drivers/hid/hid-core.c:2417 [inline]
hid_add_device+0x33c/0x9a0 drivers/hid/hid-core.c:2366
usbhid_probe+0xa81/0xfa0 drivers/hid/usbhid/hid-core.c:1386
usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:361
really_probe+0x290/0xac0 drivers/base/dd.c:551
driver_probe_device+0x223/0x350 drivers/base/dd.c:724
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:831
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
__device_attach+0x217/0x390 drivers/base/dd.c:897
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0x1459/0x1bf0 drivers/base/core.c:2487
usb_set_configuration+0xe47/0x17d0 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0xaf/0x140 drivers/usb/core/driver.c:266
really_probe+0x290/0xac0 drivers/base/dd.c:551
driver_probe_device+0x223/0x350 drivers/base/dd.c:724
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:831
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
__device_attach+0x217/0x390 drivers/base/dd.c:897
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0x1459/0x1bf0 drivers/base/core.c:2487
usb_new_device.cold+0x540/0xcd0 drivers/usb/core/hub.c:2538
hub_port_connect drivers/usb/core/hub.c:5185 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5325 [inline]
port_event drivers/usb/core/hub.c:5471 [inline]
hub_event+0x21cb/0x4300 drivers/usb/core/hub.c:5553
process_one_work+0x94b/0x1620 kernel/workqueue.c:2264
worker_thread+0x96/0xe20 kernel/workqueue.c:2410
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 12:
save_stack+0x1b/0x80 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:337 [inline]
__kasan_slab_free+0x117/0x160 mm/kasan/common.c:476
slab_free_hook mm/slub.c:1444 [inline]
slab_free_freelist_hook mm/slub.c:1477 [inline]
slab_free mm/slub.c:3024 [inline]
kfree+0xd5/0x300 mm/slub.c:3976
urb_destroy drivers/usb/core/urb.c:26 [inline]
kref_put include/linux/kref.h:65 [inline]
usb_free_urb.part.0+0xaf/0x110 drivers/usb/core/urb.c:96
usb_free_urb+0x1b/0x30 drivers/usb/core/urb.c:95
usb_start_wait_urb+0x1e8/0x4c0 drivers/usb/core/message.c:79
usb_internal_control_msg drivers/usb/core/message.c:101 [inline]
usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:152
get_port_status drivers/usb/core/hub.c:570 [inline]
hub_ext_port_status+0x125/0x460 drivers/usb/core/hub.c:587
hub_port_status drivers/usb/core/hub.c:609 [inline]
hub_activate+0x51f/0x17c0 drivers/usb/core/hub.c:1112
process_one_work+0x94b/0x1620 kernel/workqueue.c:2264
worker_thread+0x96/0xe20 kernel/workqueue.c:2410
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881d4f43a00
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 0 bytes to the right of
192-byte region [ffff8881d4f43a00, ffff8881d4f43ac0)
The buggy address belongs to the page:
page:ffffea000753d0c0 refcount:1 mapcount:0 mapping:ffff8881da002a00 index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 ffffea0007567200 0000000300000003 ffff8881da002a00
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881d4f43980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8881d4f43a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881d4f43a80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
^
ffff8881d4f43b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881d4f43b80: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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[Hillf Danton]

Mon, 10 Feb 2020 17:16:12 -0800 (PST)

--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1920,16 +1920,28 @@ int hid_connect(struct hid_device *hdev,
if (hid_hiddev(hdev))
connect_mask |= HID_CONNECT_HIDDEV_FORCE;

- if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
- connect_mask & HID_CONNECT_HIDINPUT_FORCE))
+ if (connect_mask & HID_CONNECT_HIDINPUT) {
+ ret = hidinput_connect(hdev, connect_mask &
+ HID_CONNECT_HIDINPUT_FORCE);
+ if (ret)
+ return ret;
hdev->claimed |= HID_CLAIMED_INPUT;
+ }

- if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
- !hdev->hiddev_connect(hdev,
- connect_mask & HID_CONNECT_HIDDEV_FORCE))
+ if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect) {
+ ret = hdev->hiddev_connect(hdev, connect_mask &
+ HID_CONNECT_HIDDEV_FORCE);
+ if (ret)
+ return ret;
hdev->claimed |= HID_CLAIMED_HIDDEV;
- if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
+ }
+
+ if (connect_mask & HID_CONNECT_HIDRAW) {
+ ret = hidraw_connect(hdev);
+ if (ret)
+ return ret;
hdev->claimed |= HID_CLAIMED_HIDRAW;
+ }

if (connect_mask & HID_CONNECT_DRIVER)
hdev->claimed |= HID_CLAIMED_DRIVER;

[Oliver Neukum]

Am Montag, den 10.02.2020, 17:16 -0800 schrieb syzbot:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: e5cd56e9 usb: gadget: add raw-gadget interface
> git tree: https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=1517fed9e00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=8cff427cc8996115
> dashboard link: https://syzkaller.appspot.com/bug?extid=07efed3bc5a1407bd742
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=147026b5e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1683b6b5e00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+07efed...@syzkaller.appspotmail.com
>
> betop 0003:20BC:5500.0001: unknown main item tag 0x0
> betop 0003:20BC:5500.0001: hidraw0: USB HID v0.00 Device [HID 20bc:5500] on usb-dummy_hcd.0-1/input0
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in set_bit include/asm-generic/bitops/instrumented-atomic.h:28 [inline]
> BUG: KASAN: slab-out-of-bounds in betopff_init drivers/hid/hid-betopff.c:99 [inline]
> BUG: KASAN: slab-out-of-bounds in betop_probe+0x396/0x570 drivers/hid/hid-betopff.c:134
> Write of size 8 at addr ffff8881d4f43ac0 by task kworker/1:2/94
>

> Freed by task 12:
> save_stack+0x1b/0x80 mm/kasan/common.c:72
> set_track mm/kasan/common.c:80 [inline]
> kasan_set_free_info mm/kasan/common.c:337 [inline]
> __kasan_slab_free+0x117/0x160 mm/kasan/common.c:476
> slab_free_hook mm/slub.c:1444 [inline]
> slab_free_freelist_hook mm/slub.c:1477 [inline]
> slab_free mm/slub.c:3024 [inline]
> kfree+0xd5/0x300 mm/slub.c:3976
> urb_destroy drivers/usb/core/urb.c:26 [inline]
> kref_put include/linux/kref.h:65 [inline]
>

Hi,

this indicates that I am confused. Why are we getting an out-of-bounds
on a freed region? Is this a strange way of reporting access
to already freed memory?

Regards
Oliver

[Dmitry Vyukov]

Hi Oliver,

This is being tracked in:
https://bugzilla.kernel.org/show_bug.cgi?id=198425