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

[Peter Chen]

> On Tue, Jul 9, 2019 at 2:27 PM syzbot
> <syzbot+58e201002fe1e775e1ae@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    7829a896 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=118d136da00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=f6d4561982f71f63
> > dashboard link: https://syzkaller.appspot.com/bug?extid=58e201002fe1e775e1ae
> > 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+58e201002fe1e775e1ae@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > dummy_hcd dummy_hcd.5: no ep configured for urb 00000000c6093b7b
> > xpad 6-1:0.169: xpad_irq_out - usb_submit_urb failed with result -19
> > ==================================================================
> > BUG: KASAN: use-after-free in debug_spin_lock_before
> > kernel/locking/spinlock_debug.c:83 [inline]
> > BUG: KASAN: use-after-free in do_raw_spin_lock+0x24d/0x280
> > kernel/locking/spinlock_debug.c:112
> > Read of size 4 at addr ffff8881d0e584dc by task kworker/1:4/2786
> >

It should due to URB is freed at xpad_disconnect, but xpad_irq_out
still tries to access
freed URB.

Peter

#syz test: https://github.com/google/kasan.git 7829a896

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 6b40a1c68f9f..32b7a199b580 100644
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -1850,6 +1850,7 @@ static void xpad_disconnect(struct usb_interface *intf)

        xpad_deinit_input(xpad);

+       usb_kill_urb(xpad->irq_out);
        /*
         * Now that both input device and LED device are gone we can
         * stop output URB.


> > CPU: 1 PID: 2786 Comm: kworker/1:4 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:
> >   <IRQ>
> >   __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
> >   debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
> >   do_raw_spin_lock+0x24d/0x280 kernel/locking/spinlock_debug.c:112
> >   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:117 [inline]
> >   _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:159
> >   __wake_up_common_lock+0xb0/0x170 kernel/sched/wait.c:121
> >   __usb_unanchor_urb drivers/usb/core/urb.c:154 [inline]
> >   usb_anchor_resume_wakeups+0xbe/0xe0 drivers/usb/core/urb.c:148
> >   __usb_hcd_giveback_urb+0x1fa/0x470 drivers/usb/core/hcd.c:1760
> >   usb_hcd_giveback_urb+0x34a/0x400 drivers/usb/core/hcd.c:1823
> >   dummy_timer+0x1022/0x2df4 drivers/usb/gadget/udc/dummy_hcd.c:1965
> >   call_timer_fn+0x15e/0x5e0 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+0x597/0x1410 kernel/time/timer.c:1698
> >   __do_softirq+0x219/0x8b0 kernel/softirq.c:292
> >   invoke_softirq kernel/softirq.c:373 [inline]
> >   irq_exit+0x17c/0x1a0 kernel/softirq.c:413
> >   exiting_irq arch/x86/include/asm/apic.h:536 [inline]
> >   smp_apic_timer_interrupt+0xe2/0x480 arch/x86/kernel/apic/apic.c:1068
> >   apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
> >   </IRQ>
> > RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
> > RIP: 0010:console_unlock+0x9db/0xbf0 kernel/printk/printk.c:2471
> > Code: 00 89 ee 48 c7 c7 e0 eb f2 86 e8 50 a4 03 00 65 ff 0d 51 56 da 7e e9
> > 11 fa ff ff e8 af 43 15 00 e8 ba 69 1a 00 ff 74 24 30 9d <e9> 31 fe ff ff
> > e8 9b 43 15 00 48 8b bc 24 80 00 00 00 c7 05 d9 e6
> > RSP: 0018:ffff8881d251ecb8 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13
> > RAX: 0000000000000007 RBX: 0000000000000200 RCX: 1ffff11039d43729
> > RDX: 0000000000000000 RSI: ffff8881cea1b928 RDI: ffff8881cea1b834
> > RBP: 0000000000000000 R08: ffff8881cea1b000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000046
> > R13: ffffffff828cb580 R14: ffffffff8726a520 R15: dffffc0000000000
> >   vprintk_emit+0x171/0x3e0 kernel/printk/printk.c:1986
> >   vprintk_func+0x75/0x113 kernel/printk/printk_safe.c:386
> >   printk+0xba/0xed kernel/printk/printk.c:2046
> >   really_probe.cold+0x69/0x122 drivers/base/dd.c:577
> >   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_serial_probe.cold+0x13e6/0x25d0 drivers/usb/serial/usb-serial.c:1057
> >   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
> >
> > Allocated by task 17:
> >   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]
> >   xpad_probe+0x24b/0x1b20 drivers/input/joystick/xpad.c:1717
> >   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 107:
> >   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
> >   xpad_disconnect+0x1cb/0x4a3 drivers/input/joystick/xpad.c:1865
> >   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
> >   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 ffff8881d0e58480
> >   which belongs to the cache kmalloc-1k of size 1024
> > The buggy address is located 92 bytes inside of
> >   1024-byte region [ffff8881d0e58480, ffff8881d0e58880)
> > The buggy address belongs to the page:
> > page:ffffea0007439600 refcount:1 mapcount:0 mapping:ffff8881dac02a00
> > index:0x0 compound_mapcount: 0
> > flags: 0x200000000010200(slab|head)
> > raw: 0200000000010200 0000000000000000 0000000d00000001 ffff8881dac02a00
> > raw: 0000000000000000 00000000800e000e 00000001ffffffff 0000000000000000
> > page dumped because: kasan: bad access detected
> >
> > Memory state around the buggy address:
> >   ffff8881d0e58380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >   ffff8881d0e58400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > ffff8881d0e58480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >                                                      ^
> >   ffff8881d0e58500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >   ffff8881d0e58580: 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 syzkaller@xxxxxxxxxxxxxxxxx
> >
> > syzbot will keep track of this bug report. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> Looks like a bug in the xpad driver, adding maintainers.