syzbot


KASAN: use-after-free Read in cpia2_usb_disconnect
Status: fixed on 2019/08/05 13:45
Reported-by: syzbot+0c90fc937c84f97d0aa6@syzkaller.appspotmail.com
Fix commit: eff73de2b160 media: cpia2_usb: first wake up, then free in disconnect
First crash: 1134d, last: 1050d
Patch testing requests:
Created Duration User Patch Repo Result
2019/07/04 09:35 18m oneukum@suse.com patch https://github.com/google/kasan.git usb-fuzzer OK

Sample crash report:
cpia2: Control message failed, err val = -19
cpia2: Message: request = 0x1, start = 0xA9
cpia2: Message: count = 1, register[0] = 0x0
cpia2: Unexpected error: -19
==================================================================
BUG: KASAN: use-after-free in cpia2_usb_disconnect+0x1a4/0x1c0 drivers/media/usb/cpia2/cpia2_usb.c:898
Read of size 8 at addr ffff8881d0202c50 by task kworker/0:1/12

CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.2.0-rc6+ #13
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+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
 cpia2_usb_disconnect+0x1a4/0x1c0 drivers/media/usb/cpia2/cpia2_usb.c:898
 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:2197
 hub_port_connect drivers/usb/core/hub.c:4940 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
 port_event drivers/usb/core/hub.c:5350 [inline]
 hub_event+0x1409/0x3590 drivers/usb/core/hub.c:5432
 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

Allocated by task 12:
 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]
 cpia2_init_camera_struct+0x40/0x110 drivers/media/usb/cpia2/cpia2_core.c:2176
 cpia2_usb_probe.cold+0x37/0x45a drivers/media/usb/cpia2/cpia2_usb.c:833
 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+0x8c1/0x1016 drivers/usb/core/hub.c:2534
 hub_port_connect drivers/usb/core/hub.c:5089 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
 port_event drivers/usb/core/hub.c:5350 [inline]
 hub_event+0x1ada/0x3590 drivers/usb/core/hub.c:5432
 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

Freed by task 12:
 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
 v4l2_device_release drivers/media/v4l2-core/v4l2-device.c:55 [inline]
 kref_put include/linux/kref.h:65 [inline]
 v4l2_device_put+0x76/0x90 drivers/media/v4l2-core/v4l2-device.c:60
 cpia2_usb_disconnect+0x79/0x1c0 drivers/media/usb/cpia2/cpia2_usb.c:896
 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:2197
 hub_port_connect drivers/usb/core/hub.c:4940 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
 port_event drivers/usb/core/hub.c:5350 [inline]
 hub_event+0x1409/0x3590 drivers/usb/core/hub.c:5432
 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

The buggy address belongs to the object at ffff8881d0202200
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2640 bytes inside of
 4096-byte region [ffff8881d0202200, ffff8881d0203200)
The buggy address belongs to the page:
page:ffffea0007408000 refcount:1 mapcount:0 mapping:ffff8881dac02600 index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea0007405c00 0000000200000002 ffff8881dac02600
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d0202b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d0202b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881d0202c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8881d0202c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d0202d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-usb 2019/07/09 20:44 https://github.com/google/kasan.git usb-fuzzer 7829a896a587 f62e1e85 .config log report syz C
ci2-upstream-usb 2019/07/03 01:00 https://github.com/google/kasan.git usb-fuzzer 7829a896a587 55565fa0 .config log report syz C
ci2-upstream-usb 2019/04/16 07:31 https://github.com/google/kasan.git usb-fuzzer 9a33b36996cb 505ab413 .config log report syz