[alsa-devel] KASAN: use-after-free Read in build_audio_procunit

syzbot syzbot+fd965c77e4711eb13b82 at syzkaller.appspotmail.com
Thu Oct 24 15:47:08 CEST 2019 

Hello,

syzbot found the following crash on:

HEAD commit:    22be26f7 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=17cdccc4e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5
dashboard link: https://syzkaller.appspot.com/bug?extid=fd965c77e4711eb13b82
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13fe752f600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17989fd8e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+fd965c77e4711eb13b82 at syzkaller.appspotmail.com

usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: syz
usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
==================================================================
BUG: KASAN: use-after-free in uac_extension_unit_iExtension  
include/uapi/linux/usb/audio.h:483 [inline]
BUG: KASAN: use-after-free in build_audio_procunit+0xeab/0x13f0  
sound/usb/mixer.c:2434
Read of size 1 at addr ffff8881d4c0140d by task kworker/0:1/12

CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.4.0-rc3+ #0
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.constprop.0+0x36/0x50 mm/kasan/report.c:374
  __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506
  kasan_report+0xe/0x20 mm/kasan/common.c:634
  uac_extension_unit_iExtension include/uapi/linux/usb/audio.h:483 [inline]
  build_audio_procunit+0xeab/0x13f0 sound/usb/mixer.c:2434
  parse_audio_extension_unit sound/usb/mixer.c:2483 [inline]
  parse_audio_unit+0x1812/0x36f0 sound/usb/mixer.c:2761
  snd_usb_mixer_controls+0x715/0xb90 sound/usb/mixer.c:3095
  snd_usb_create_mixer+0x2b5/0x1890 sound/usb/mixer.c:3445
  usb_audio_probe+0xc76/0x2010 sound/usb/card.c:653
  usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
  really_probe+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x104/0x210 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
  device_add+0xae6/0x16f0 drivers/base/core.c:2201
  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+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x104/0x210 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
  device_add+0xae6/0x16f0 drivers/base/core.c:2201
  usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
  hub_port_connect drivers/usb/core/hub.c:5183 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5323 [inline]
  port_event drivers/usb/core/hub.c:5469 [inline]
  hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551
  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 12:
  save_stack+0x1b/0x80 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  __kasan_kmalloc mm/kasan/common.c:510 [inline]
  __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:483
  kmalloc include/linux/slab.h:561 [inline]
  usb_alloc_urb+0x65/0xb0 drivers/usb/core/urb.c:73
  usb_internal_control_msg drivers/usb/core/message.c:94 [inline]
  usb_control_msg+0x1c9/0x4a0 drivers/usb/core/message.c:152
  usb_get_descriptor+0xc1/0x1b0 drivers/usb/core/message.c:647
  usb_get_configuration+0x28e/0x3050 drivers/usb/core/config.c:836
  usb_enumerate_device drivers/usb/core/hub.c:2369 [inline]
  usb_new_device+0xd3/0x160 drivers/usb/core/hub.c:2505
  hub_port_connect drivers/usb/core/hub.c:5183 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5323 [inline]
  port_event drivers/usb/core/hub.c:5469 [inline]
  hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551
  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 12:
  save_stack+0x1b/0x80 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  kasan_set_free_info mm/kasan/common.c:332 [inline]
  __kasan_slab_free+0x130/0x180 mm/kasan/common.c:471
  slab_free_hook mm/slub.c:1424 [inline]
  slab_free_freelist_hook mm/slub.c:1475 [inline]
  slab_free mm/slub.c:3018 [inline]
  kfree+0xe4/0x320 mm/slub.c:3967
  urb_destroy drivers/usb/core/urb.c:26 [inline]
  kref_put include/linux/kref.h:65 [inline]
  usb_free_urb.part.0+0x7a/0xc0 drivers/usb/core/urb.c:95
  usb_free_urb+0x1b/0x30 drivers/usb/core/urb.c:94
  usb_start_wait_urb+0x1e5/0x2b0 drivers/usb/core/message.c:79
  usb_internal_control_msg drivers/usb/core/message.c:101 [inline]
  usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:152
  usb_get_descriptor+0xc1/0x1b0 drivers/usb/core/message.c:647
  usb_get_configuration+0x28e/0x3050 drivers/usb/core/config.c:836
  usb_enumerate_device drivers/usb/core/hub.c:2369 [inline]
  usb_new_device+0xd3/0x160 drivers/usb/core/hub.c:2505
  hub_port_connect drivers/usb/core/hub.c:5183 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5323 [inline]
  port_event drivers/usb/core/hub.c:5469 [inline]
  hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551
  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 ffff8881d4c01400
  which belongs to the cache kmalloc-192 of size 192
The buggy address is located 13 bytes inside of
  192-byte region [ffff8881d4c01400, ffff8881d4c014c0)
The buggy address belongs to the page:
page:ffffea0007530040 refcount:1 mapcount:0 mapping:ffff8881da002a00  
index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 ffffea000754fec0 0000000200000002 ffff8881da002a00
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8881d4c01300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff8881d4c01380: 00 00 00 07 fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8881d4c01400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                       ^
  ffff8881d4c01480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
  ffff8881d4c01500: 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.
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