Date:   Tue, 5 Sep 2017 13:12:14 +0200
From:   Andrey Konovalov <andreyknvl@...gle.com>
To:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        Ingo Molnar <mingo@...nel.org>,
        Fabian Frederick <fabf@...net.be>,
        Takashi Sakamoto <o-takashi@...amocchi.jp>,
        alsa-devel@...a-project.org, LKML <linux-kernel@...r.kernel.org>
Cc:     Dmitry Vyukov <dvyukov@...gle.com>,
        Kostya Serebryany <kcc@...gle.com>,
        syzkaller <syzkaller@...glegroups.com>
Subject: usb/midi: use-after-free in snd_rawmidi_dev_seq_free

Hi!

While working on adding USB fuzzing support to syzkaller, I got the
following crash.

On commit 81a84ad3cb5711cec79f4dd53a4ce026b092c432 (4.13+).

My .config is attached. I don't have a reproducer for this bug.

==================================================================
BUG: KASAN: use-after-free in snd_rawmidi_dev_seq_free+0x69/0x70
sound/core/rawmidi.c:1617
Write of size 8 at addr ffff88006c611d90 by task kworker/2:1/567

CPU: 2 PID: 567 Comm: kworker/2:1 Not tainted 4.13.0+ #29
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: events autoload_drivers
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x192/0x22c lib/dump_stack.c:52
 print_address_description+0x78/0x280 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x230/0x340 mm/kasan/report.c:409
 __asan_report_store8_noabort+0x1c/0x20 mm/kasan/report.c:435
 snd_rawmidi_dev_seq_free+0x69/0x70 sound/core/rawmidi.c:1617
 snd_seq_dev_release+0x4f/0x70 sound/core/seq_device.c:192
 device_release+0x13f/0x210 drivers/base/core.c:814
 kobject_cleanup lib/kobject.c:648 [inline]
 kobject_release lib/kobject.c:677 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x145/0x240 lib/kobject.c:694
 put_device+0x25/0x30 drivers/base/core.c:1799
 klist_devices_put+0x36/0x40 drivers/base/bus.c:827
 klist_next+0x264/0x4a0 lib/klist.c:403
 next_device drivers/base/bus.c:270 [inline]
 bus_for_each_dev+0x17e/0x210 drivers/base/bus.c:312
 autoload_drivers+0x3b/0x50 sound/core/seq_device.c:117
 process_one_work+0x9fb/0x1570 kernel/workqueue.c:2097
 worker_thread+0x1e4/0x1350 kernel/workqueue.c:2231
 kthread+0x324/0x3f0 kernel/kthread.c:231
 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425

Allocated by task 567:
 save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x66/0x170 mm/slub.c:2739
 kmalloc include/linux/slab.h:493 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 snd_rawmidi_new+0x111/0x500 sound/core/rawmidi.c:1535
 snd_usbmidi_create_rawmidi sound/usb/midi.c:2221 [inline]
 __snd_usbmidi_create+0x5cb/0x2700 sound/usb/midi.c:2450
 snd_usbmidi_create sound/usb/midi.h:53 [inline]
 create_any_midi_quirk+0x54/0x70 sound/usb/quirks.c:103
 snd_usb_create_quirk+0x92/0x100 sound/usb/quirks.c:561
 usb_audio_probe+0xf98/0x2aa0 sound/usb/card.c:598
 usb_probe_interface+0x351/0x8d0 drivers/usb/core/driver.c:361
 really_probe drivers/base/dd.c:385 [inline]
 driver_probe_device+0x610/0xa00 drivers/base/dd.c:529
 __device_attach_driver+0x230/0x290 drivers/base/dd.c:625
 bus_for_each_drv+0x15e/0x210 drivers/base/bus.c:463
 __device_attach+0x269/0x3c0 drivers/base/dd.c:682
 device_initial_probe+0x1f/0x30 drivers/base/dd.c:729
 bus_probe_device+0x1da/0x280 drivers/base/bus.c:523
 device_add+0xcf9/0x1640 drivers/base/core.c:1703
 usb_set_configuration+0x1064/0x1890 drivers/usb/core/message.c:1932
 generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
 usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
 really_probe drivers/base/dd.c:385 [inline]
 driver_probe_device+0x610/0xa00 drivers/base/dd.c:529
 __device_attach_driver+0x230/0x290 drivers/base/dd.c:625
 bus_for_each_drv+0x15e/0x210 drivers/base/bus.c:463
 __device_attach+0x269/0x3c0 drivers/base/dd.c:682
 device_initial_probe+0x1f/0x30 drivers/base/dd.c:729
 bus_probe_device+0x1da/0x280 drivers/base/bus.c:523
 device_add+0xcf9/0x1640 drivers/base/core.c:1703
 usb_new_device+0x91d/0x17a0 drivers/usb/core/hub.c:2457
 hub_port_connect drivers/usb/core/hub.c:4890 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:4996 [inline]
 port_event drivers/usb/core/hub.c:5102 [inline]
 hub_event+0x261c/0x3960 drivers/usb/core/hub.c:5186
 process_one_work+0x9fb/0x1570 kernel/workqueue.c:2097
 worker_thread+0x1e4/0x1350 kernel/workqueue.c:2231
 kthread+0x324/0x3f0 kernel/kthread.c:231
 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425

Freed by task 1454:
 save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:524
 slab_free_hook mm/slub.c:1357 [inline]
 slab_free_freelist_hook mm/slub.c:1379 [inline]
 slab_free mm/slub.c:2955 [inline]
 kfree+0x96/0x1a0 mm/slub.c:3883
 release_rawmidi_device+0x1e/0x30 sound/core/rawmidi.c:1502
 device_release+0x13f/0x210 drivers/base/core.c:814
 kobject_cleanup lib/kobject.c:648 [inline]
 kobject_release lib/kobject.c:677 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x145/0x240 lib/kobject.c:694
 put_device+0x25/0x30 drivers/base/core.c:1799
 snd_rawmidi_free.part.15+0x14b/0x190 sound/core/rawmidi.c:1603
 snd_rawmidi_free sound/core/rawmidi.c:1589 [inline]
 snd_rawmidi_dev_free+0x43/0x60 sound/core/rawmidi.c:1610
 __snd_device_free+0x1e5/0x380 sound/core/device.c:91
 snd_device_free_all+0x8f/0xe0 sound/core/device.c:244
 snd_card_do_free sound/core/init.c:463 [inline]
 release_card_device+0x26/0x150 sound/core/init.c:181
 device_release+0x13f/0x210 drivers/base/core.c:814
 kobject_cleanup lib/kobject.c:648 [inline]
 kobject_release lib/kobject.c:677 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x145/0x240 lib/kobject.c:694
 put_device+0x25/0x30 drivers/base/core.c:1799
 snd_card_free_when_closed+0x34/0x50 sound/core/init.c:491
 usb_audio_disconnect+0x5fb/0x860 sound/usb/card.c:684
 usb_unbind_interface+0x216/0xa90 drivers/usb/core/driver.c:423
 __device_release_driver drivers/base/dd.c:833 [inline]
 device_release_driver_internal+0x4da/0x5a0 drivers/base/dd.c:863
 device_release_driver+0x1e/0x30 drivers/base/dd.c:888
 bus_remove_device+0x2da/0x490 drivers/base/bus.c:565
 device_del+0x5b1/0xaa0 drivers/base/core.c:1853
 usb_disable_device+0x1e9/0x680 drivers/usb/core/message.c:1170
 usb_disconnect+0x2ca/0x830 drivers/usb/core/hub.c:2124
 hub_port_connect drivers/usb/core/hub.c:4741 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:4996 [inline]
 port_event drivers/usb/core/hub.c:5102 [inline]
 hub_event+0x14d8/0x3960 drivers/usb/core/hub.c:5186
 process_one_work+0x9fb/0x1570 kernel/workqueue.c:2097
 worker_thread+0x1e4/0x1350 kernel/workqueue.c:2231
 kthread+0x324/0x3f0 kernel/kthread.c:231
 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425

The buggy address belongs to the object at ffff88006c611980
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1040 bytes inside of
 2048-byte region [ffff88006c611980, ffff88006c612180)
The buggy address belongs to the page:
page:ffffea0001b18400 count:1 mapcount:0 mapping:          (null)
index:0xffff88006c617700 compound_mapcount: 0
flags: 0x500000000008100(slab|head)
raw: 0500000000008100 0000000000000000 ffff88006c617700 00000001800f0007
raw: ffffea0001b10400 0000000300000003 ffff88003e803040 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88006c611c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88006c611d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88006c611d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88006c611e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88006c611e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Download attachment ".config" of type "application/octet-stream" (123939 bytes)

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