Re: KASAN: use-after-free Read in wdm_int_callback

From: syzbot
Date: Fri Aug 09 2019 - 05:26:11 EST

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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+1a3765ef3c0d49d36a75@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
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:
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
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:
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
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
==================================================================

Next message: Anup Patel: "Re: [PATCH v4 00/20] KVM RISC-V Support"
Previous message: Dan Carpenter: "Re: [PATCH v2 1/2] binder: Add default binder devices through binderfs when configured"
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