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

From: syzbot
Date: Mon Dec 09 2019 - 06:05:16 EST

Hello,

syzbot found the following crash on:

HEAD commit: 1f22d15c 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=11110cdee00000
kernel config: https://syzkaller.appspot.com/x/.config?x=8ccee2968018adcb
dashboard link: https://syzkaller.appspot.com/bug?extid=00b7ed8a789d74bb5a4b
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1342f446e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=155fd196e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+00b7ed8a789d74bb5a4b@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: slab-out-of-bounds in clear_bit include/asm-generic/bitops-instrumented.h:56 [inline]
BUG: KASAN: slab-out-of-bounds in sysrq_handle_keypress drivers/tty/sysrq.c:845 [inline]
BUG: KASAN: slab-out-of-bounds in sysrq_filter+0x8ff/0xeb0 drivers/tty/sysrq.c:884
Write of size 8 at addr ffff8881cff93dc8 by task syz-executor237/1717

CPU: 1 PID: 1717 Comm: syz-executor237 Not tainted 5.4.0-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+0xef/0x16e lib/dump_stack.c:118
print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506
kasan_report+0xe/0x20 mm/kasan/common.c:638
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x128/0x190 mm/kasan/generic.c:192
clear_bit include/asm-generic/bitops-instrumented.h:56 [inline]
sysrq_handle_keypress drivers/tty/sysrq.c:845 [inline]
sysrq_filter+0x8ff/0xeb0 drivers/tty/sysrq.c:884
input_to_handler+0x152/0x4c0 drivers/input/input.c:102
input_pass_values.part.0+0x2de/0x710 drivers/input/input.c:145
input_pass_values drivers/input/input.c:949 [inline]
input_set_keycode+0x290/0x320 drivers/input/input.c:954
evdev_handle_set_keycode_v2+0xc4/0x120 drivers/input/evdev.c:882
evdev_do_ioctl drivers/input/evdev.c:1150 [inline]
evdev_ioctl_handler+0xd49/0x19f0 drivers/input/evdev.c:1284
vfs_ioctl fs/ioctl.c:47 [inline]
file_ioctl fs/ioctl.c:539 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:726
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:743
__do_sys_ioctl fs/ioctl.c:750 [inline]
__se_sys_ioctl fs/ioctl.c:748 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:748
do_syscall_64+0xb7/0x5b0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x444dc9
Code: e8 bc af 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 1b d8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffea62b3f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444dc9
RDX: 00000000200000c0 RSI: 0000000040284504 RDI: 0000000000000004
RBP: 00000000006cf018 R08: 7d03000000008300 R09: 00000000004002e0
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402a70
R13: 0000000000402b00 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 78:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_kmalloc mm/kasan/common.c:512 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:485
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:670 [inline]
sysrq_connect+0x46/0x290 drivers/tty/sysrq.c:902
input_attach_handler+0x194/0x200 drivers/input/input.c:1024
input_register_device.cold+0xf5/0x246 drivers/input/input.c:2224
hidinput_connect+0x4f8d/0xdb90 drivers/hid/hid-input.c:1927
hid_connect+0x965/0xbb0 drivers/hid/hid-core.c:1923
hid_hw_start drivers/hid/hid-core.c:2027 [inline]
hid_hw_start+0xa2/0x130 drivers/hid/hid-core.c:2018
ms_probe+0x159/0x4d0 drivers/hid/hid-microsoft.c:394
hid_device_probe+0x2be/0x3f0 drivers/hid/hid-core.c:2255
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x104/0x210 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0x1480/0x1c20 drivers/base/core.c:2487
hid_add_device drivers/hid/hid-core.c:2411 [inline]
hid_add_device+0x33c/0x9a0 drivers/hid/hid-core.c:2360
usbhid_probe+0xa81/0xfa0 drivers/hid/usbhid/hid-core.c:1386
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x104/0x210 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0x1480/0x1c20 drivers/base/core.c:2487
usb_set_configuration+0xe67/0x1740 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+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x104/0x210 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0x1480/0x1c20 drivers/base/core.c:2487
usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2537
hub_port_connect drivers/usb/core/hub.c:5184 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
port_event drivers/usb/core/hub.c:5470 [inline]
hub_event+0x1e59/0x3860 drivers/usb/core/hub.c:5552
process_one_work+0x92b/0x1530 kernel/workqueue.c:2264
process_scheduled_works kernel/workqueue.c:2326 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2412
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 350:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
kasan_set_free_info mm/kasan/common.c:334 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:473
slab_free_hook mm/slub.c:1425 [inline]
slab_free_freelist_hook mm/slub.c:1458 [inline]
slab_free mm/slub.c:3005 [inline]
kfree+0xdc/0x310 mm/slub.c:3957
load_elf_binary+0x2435/0x4f00 fs/binfmt_elf.c:1088
search_binary_handler fs/exec.c:1658 [inline]
search_binary_handler+0x16b/0x580 fs/exec.c:1635
exec_binprm fs/exec.c:1701 [inline]
__do_execve_file.isra.0+0x1304/0x21e0 fs/exec.c:1821
do_execveat_common fs/exec.c:1867 [inline]
do_execve fs/exec.c:1884 [inline]
__do_sys_execve fs/exec.c:1960 [inline]
__se_sys_execve fs/exec.c:1955 [inline]
__x64_sys_execve+0x8a/0xb0 fs/exec.c:1955
do_syscall_64+0xb7/0x5b0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881cff93c00
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 456 bytes inside of
512-byte region [ffff8881cff93c00, ffff8881cff93e00)
The buggy address belongs to the page:
page:ffffea00073fe400 refcount:1 mapcount:0 mapping:ffff8881da402500 index:0x0 compound_mapcount: 0
raw: 0200000000010200 0000000000000000 0000000100000001 ffff8881da402500
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cff93c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881cff93d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881cff93d80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
^
ffff8881cff93e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881cff93e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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