Hello,
syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: use-after-free Read in hidraw_ioctl
==================================================================
BUG: KASAN: use-after-free in hidraw_ioctl+0x609/0xaf0
drivers/hid/hidraw.c:380
Read of size 4 at addr ffff8881d2db4218 by task syz-executor.1/3343
CPU: 1 PID: 3343 Comm: syz-executor.1 Not tainted 5.2.0-rc6+ #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+0x67/0x231 mm/kasan/report.c:188
__kasan_report.cold+0x1a/0x32 mm/kasan/report.c:317
kasan_report+0xe/0x20 mm/kasan/common.c:614
hidraw_ioctl+0x609/0xaf0 drivers/hid/hidraw.c:380
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xcda/0x12e0 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+0xb7/0x560 arch/x86/entry/common.c:301
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:00007fac801dac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 00000000200015c0 RSI: 0000000080044801 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fac801db6d4
R13: 00000000004c21ee R14: 00000000004d53f8 R15: 00000000ffffffff
Allocated by task 2911:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_kmalloc mm/kasan/common.c:489 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:462
kmalloc include/linux/slab.h:547 [inline]
kzalloc include/linux/slab.h:742 [inline]
hid_allocate_device+0x3e/0x480 drivers/hid/hid-core.c:2389
usbhid_probe+0x23e/0xfa0 drivers/hid/usbhid/hid-core.c:1321
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
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+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_new_device.cold+0x6a4/0xe61 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+0x1abd/0x3550 drivers/usb/core/hub.c:5441
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Freed by task 2895:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:451
slab_free_hook mm/slub.c:1421 [inline]
slab_free_freelist_hook mm/slub.c:1448 [inline]
slab_free mm/slub.c:2994 [inline]
kfree+0xd7/0x280 mm/slub.c:3949
device_release+0x71/0x200 drivers/base/core.c:1064
kobject_cleanup lib/kobject.c:691 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x171/0x280 lib/kobject.c:737
put_device+0x1b/0x30 drivers/base/core.c:2210
usbhid_disconnect+0x90/0xd0 drivers/hid/usbhid/hid-core.c:1413
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1081 [inline]
device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1112
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x460/0xb80 drivers/base/core.c:2274
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x830 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x13bd/0x3550 drivers/usb/core/hub.c:5441
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
The buggy address belongs to the object at ffff8881d2db4200
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 24 bytes inside of
8192-byte region [ffff8881d2db4200, ffff8881d2db6200)
The buggy address belongs to the page:
page:ffffea00074b6c00 refcount:1 mapcount:0 mapping:ffff8881dac02400
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea0007176e00 0000000300000003 ffff8881dac02400
raw: 0000000000000000 0000000000030003 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881d2db4100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881d2db4180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881d2db4200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d2db4280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d2db4300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Tested on:
commit: 6a3599ce 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=1637707a600000
kernel config: https://syzkaller.appspot.com/x/.config?x=700ca426ab83faae
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=15db9586600000
