KASAN: use-after-free Read in wdm_int_callback

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syzbot

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Aug 7, 2019, 10:28:06ā€ÆAM8/7/19
to andre...@google.com, baijia...@gmail.com, big...@linutronix.de, colin...@canonical.com, gre...@linuxfoundation.org, linux-...@vger.kernel.org, linu...@vger.kernel.org, syzkall...@googlegroups.com, yueha...@huawei.com
Hello,

syzbot found the following crash on:

HEAD commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=162e6352600000
kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3765ef3c0d49d36a75
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1a3765...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in wdm_int_callback+0x459/0x4c0
drivers/usb/class/cdc-wdm.c:239
Read of size 8 at addr ffff8881cf42e410 by task udevd/6344

CPU: 0 PID: 6344 Comm: udevd Not tainted 5.3.0-rc2+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__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
wdm_int_callback+0x459/0x4c0 drivers/usb/class/cdc-wdm.c:239
__usb_hcd_giveback_urb+0x1f2/0x470 drivers/usb/core/hcd.c:1757
usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1822
dummy_timer+0x120f/0x2fa2 drivers/usb/gadget/udc/dummy_hcd.c:1965
call_timer_fn+0x179/0x650 kernel/time/timer.c:1322
expire_timers kernel/time/timer.c:1366 [inline]
__run_timers kernel/time/timer.c:1685 [inline]
__run_timers kernel/time/timer.c:1653 [inline]
run_timer_softirq+0x5cc/0x14b0 kernel/time/timer.c:1698
__do_softirq+0x221/0x912 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x178/0x1a0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:537 [inline]
smp_apic_timer_interrupt+0x12f/0x500 arch/x86/kernel/apic/apic.c:1095
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
</IRQ>
RIP: 0010:rb_prev+0xbd/0x130 lib/rbtree.c:550
Code: 75 20 48 89 d8 48 c1 e8 03 42 80 3c 28 00 75 67 4c 8b 23 48 89 dd 4c
89 e3 48 83 e3 fc 48 89 d8 75 c8 48 83 c4 08 5b 5d 41 5c <41> 5d c3 48 89
d0 48 8d 78 08 48 89 fa 48 c1 ea 03 80 3c 1a 00 75
RSP: 0018:ffff8881a447fba0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: ffff8881d6651920 RBX: 0000000000000004 RCX: ffffffff812666d0
RDX: 1ffff1103acca326 RSI: ffffffff815ab46e RDI: ffff8881d6651930
RBP: ffff8881d6651a20 R08: ffff8881cfdce000 R09: ffffed103a910587
R10: ffffed103a910586 R11: ffff8881d4882c33 R12: 0000000000000005
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
browse_rb mm/mmap.c:365 [inline]
validate_mm+0x3dd/0x610 mm/mmap.c:418
mmap_region+0xfbc/0x13c0 mm/mmap.c:1811
do_mmap+0x831/0x1070 mm/mmap.c:1561
do_mmap_pgoff include/linux/mm.h:2374 [inline]
vm_mmap_pgoff+0x195/0x1f0 mm/util.c:391
ksys_mmap_pgoff+0xd8/0x5b0 mm/mmap.c:1611
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2c0f046d0a
Code: b8 ff ff ff ff e9 fa fe ff ff 48 63 fb b8 03 00 00 00 0f 05 b8 ff ff
ff ff e9 e6 fe ff ff 90 90 49 89 ca b8 09 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 01 c3 48 8b 0d fe c0 2a 00 31 d2 48 29 c2 64
RSP: 002b:00007ffe7106e018 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 000000000137e6b0 RCX: 00007f2c0f046d0a
RDX: 0000000000000003 RSI: 0000000000001000 RDI: 0000000000000000
RBP: 0000000000001000 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000420724
R13: 0000000000000002 R14: 0000000000420724 R15: 0000000000420724

Allocated by task 21732:
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
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:748 [inline]
wdm_create+0x56/0x1720 drivers/usb/class/cdc-wdm.c:786
wdm_probe+0x220/0x2d0 drivers/usb/class/cdc-wdm.c:922
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
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 21732:
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
wdm_create+0x542/0x1720 drivers/usb/class/cdc-wdm.c:884
wdm_probe+0x220/0x2d0 drivers/usb/class/cdc-wdm.c:922
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
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
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 ffff8881cf42e400
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 16 bytes inside of
1024-byte region [ffff8881cf42e400, ffff8881cf42e800)
The buggy address belongs to the page:
page:ffffea00073d0b00 refcount:1 mapcount:0 mapping:ffff8881da002280
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 0000000000000000 0000000600000001 ffff8881da002280
raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cf42e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cf42e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8881cf42e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881cf42e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cf42e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
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syzbot

unread,
Aug 9, 2019, 5:26:07ā€ÆAM8/9/19
to andre...@google.com, baijia...@gmail.com, big...@linutronix.de, colin...@canonical.com, gre...@linuxfoundation.org, linux-...@vger.kernel.org, linu...@vger.kernel.org, syzkall...@googlegroups.com, yueha...@huawei.com
syzbot has found a reproducer for the following crash on:

HEAD commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=15b5018c600000
kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3765ef3c0d49d36a75
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14d9a9c2600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16f1a18c600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1a3765...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in wdm_int_callback+0x459/0x4c0
drivers/usb/class/cdc-wdm.c:239
Read of size 8 at addr ffff8881cf909690 by task kworker/1:2/1742

CPU: 1 PID: 1742 Comm: kworker/1:2 Not tainted 5.3.0-rc2+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
<IRQ>
__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
wdm_int_callback+0x459/0x4c0 drivers/usb/class/cdc-wdm.c:239
__usb_hcd_giveback_urb+0x1f2/0x470 drivers/usb/core/hcd.c:1757
usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1822
dummy_timer+0x120f/0x2fa2 drivers/usb/gadget/udc/dummy_hcd.c:1965
call_timer_fn+0x179/0x650 kernel/time/timer.c:1322
expire_timers kernel/time/timer.c:1366 [inline]
__run_timers kernel/time/timer.c:1685 [inline]
__run_timers kernel/time/timer.c:1653 [inline]
run_timer_softirq+0x5cc/0x14b0 kernel/time/timer.c:1698
__do_softirq+0x221/0x912 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x178/0x1a0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:537 [inline]
smp_apic_timer_interrupt+0x12f/0x500 arch/x86/kernel/apic/apic.c:1095
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
</IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:console_unlock+0xa2a/0xc40 kernel/printk/printk.c:2471
Code: 00 89 ee 48 c7 c7 20 88 d3 86 e8 81 ad 03 00 65 ff 0d 72 a1 d9 7e e9
db f9 ff ff e8 70 a1 15 00 e8 1b cb 1a 00 ff 74 24 30 9d <e9> 18 fe ff ff
e8 5c a1 15 00 48 8d 7d 08 48 89 f8 48 c1 e8 03 42
RSP: 0018:ffff8881d29feea8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: 0000000000000200 RCX: 0000000000000006
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881d3478844
RBP: 0000000000000000 R08: ffff8881d3478000 R09: fffffbfff11acd91
R10: fffffbfff11acd90 R11: ffffffff88d66c87 R12: 0000000000000061
R13: dffffc0000000000 R14: ffffffff82909100 R15: ffffffff87077190
vprintk_emit+0x171/0x3e0 kernel/printk/printk.c:1986
dev_vprintk_emit+0x4fc/0x541 drivers/base/core.c:3232
dev_printk_emit+0xba/0xf1 drivers/base/core.c:3243
__dev_printk+0x1db/0x203 drivers/base/core.c:3255
_dev_err+0xd7/0x109 drivers/base/core.c:3298
usbvision_probe.cold+0x1c1/0x1e57
drivers/media/usb/usbvision/usbvision-video.c:1442
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

Allocated by task 1742:
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 1742:
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

The buggy address belongs to the object at ffff8881cf909680
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 16 bytes inside of
1024-byte region [ffff8881cf909680, ffff8881cf909a80)
The buggy address belongs to the page:
page:ffffea00073e4200 refcount:1 mapcount:0 mapping:ffff8881da002280
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea00073eb800 0000000200000002 ffff8881da002280
raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cf909580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cf909600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8881cf909680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881cf909700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cf909780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Andrey Konovalov

unread,
Nov 19, 2019, 8:46:50ā€ÆAM11/19/19
to syzbot, baijia...@gmail.com, big...@linutronix.de, Colin Ian King, Greg Kroah-Hartman, LKML, USB list, syzkaller-bugs, yueha...@huawei.com
#syz dup: WARNING in wdm_write/usb_submit_urb

https://syzkaller.appspot.com/bug?extid=d232cca6ec42c2edb3fc

Oliver Neukum

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Nov 19, 2019, 9:17:24ā€ÆAM11/19/19
to Andrey Konovalov, syzbot, baijia...@gmail.com, big...@linutronix.de, Colin Ian King, Greg Kroah-Hartman, LKML, USB list, syzkaller-bugs, yueha...@huawei.com
Am Dienstag, den 19.11.2019, 14:46 +0100 schrieb Andrey Konovalov:
>
> #syz dup: WARNING in wdm_write/usb_submit_urb
>
> https://syzkaller.appspot.com/bug?extid=d232cca6ec42c2edb3fc

Hi,

this is a bit odd. A fix for that bug went in quite some time ago.
Is the kernel tree these tests are running on regularly updated?

Regards
Oliver

Andrey Konovalov

unread,
Nov 19, 2019, 9:33:00ā€ÆAM11/19/19
to Oliver Neukum, syzbot, baijia...@gmail.com, big...@linutronix.de, Colin Ian King, Greg Kroah-Hartman, LKML, USB list, syzkaller-bugs, yueha...@huawei.com
Hi Oliver,

The fix went in a while ago indeed, and the original WARNING bug got
closed. But this bug was never marked to be somehow related to the fix
or the WARNING bug and therefore was never closed.

Thanks!
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