[alsa-devel] KASAN: slab-out-of-bounds Read in build_audio_procunit (2)

Andrey Konovalov andreyknvl at google.com
Thu Jan 23 14:59:31 CET 2020 

On Tue, Dec 3, 2019 at 3:04 PM Andrey Konovalov <andreyknvl at google.com> wrote:
>
> On Thu, Nov 7, 2019 at 4:34 PM syzbot
> <syzbot+622d4ecb979f45c6a775 at syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    d60bbfea usb: raw: add raw-gadget interface
> > git tree:       https://github.com/google/kasan.git usb-fuzzer
> > console output: https://syzkaller.appspot.com/x/log.txt?x=132e5bcce00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=79de80330003b5f7
> > dashboard link: https://syzkaller.appspot.com/bug?extid=622d4ecb979f45c6a775
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1478c6b4e00000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=117cbf8ae00000
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+622d4ecb979f45c6a775 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
> > usb 1-1: 0:2 : does not exist
> > ==================================================================
> > BUG: KASAN: slab-out-of-bounds in uac_extension_unit_iExtension
> > include/uapi/linux/usb/audio.h:483 [inline]
> > BUG: KASAN: slab-out-of-bounds in build_audio_procunit+0xeab/0x13f0
> > sound/usb/mixer.c:2434
> > Read of size 1 at addr ffff8881d4aaa735 by task kworker/1:2/83
> >
> > CPU: 1 PID: 83 Comm: kworker/1:2 Not tainted 5.4.0-rc6+ #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:2202
> >   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:2202
> >   usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2537
> >   hub_port_connect drivers/usb/core/hub.c:5184 [inline]
> >   hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
> >   port_event drivers/usb/core/hub.c:5470 [inline]
> >   hub_event+0x1df8/0x3800 drivers/usb/core/hub.c:5552
> >   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 83:
> >   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_get_configuration+0x311/0x3100 drivers/usb/core/config.c:862
> >   usb_enumerate_device drivers/usb/core/hub.c:2370 [inline]
> >   usb_new_device+0xd3/0x160 drivers/usb/core/hub.c:2506
> >   hub_port_connect drivers/usb/core/hub.c:5184 [inline]
> >   hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
> >   port_event drivers/usb/core/hub.c:5470 [inline]
> >   hub_event+0x1df8/0x3800 drivers/usb/core/hub.c:5552
> >   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 211:
> >   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:3025 [inline]
> >   kfree+0xe4/0x320 mm/slub.c:3977
> >   do_new_mount fs/namespace.c:2827 [inline]
> >   do_mount+0x68a/0x1bf0 fs/namespace.c:3143
> >   ksys_mount+0xd7/0x150 fs/namespace.c:3352
> >   __do_sys_mount fs/namespace.c:3366 [inline]
> >   __se_sys_mount fs/namespace.c:3363 [inline]
> >   __x64_sys_mount+0xba/0x150 fs/namespace.c:3363
> >   do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:290
> >   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> >
> > The buggy address belongs to the object at ffff8881d4aaa600
> >   which belongs to the cache kmalloc-256 of size 256
> > The buggy address is located 53 bytes to the right of
> >   256-byte region [ffff8881d4aaa600, ffff8881d4aaa700)
> > The buggy address belongs to the page:
> > page:ffffea000752aa80 refcount:1 mapcount:0 mapping:ffff8881da002780
> > index:0x0 compound_mapcount: 0
> > flags: 0x200000000010200(slab|head)
> > raw: 0200000000010200 ffffea000752c900 0000000a0000000a ffff8881da002780
> > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
> > page dumped because: kasan: bad access detected
> >
> > Memory state around the buggy address:
> >   ffff8881d4aaa600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >   ffff8881d4aaa680: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
> > > ffff8881d4aaa700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >                                       ^
> >   ffff8881d4aaa780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >   ffff8881d4aaa800: 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 at googlegroups.com.
> >
> > syzbot will keep track of this bug report. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > syzbot can test patches for this bug, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
>
> #syz fix: ALSA: usb-audio: Fix incorrect size check for
> processing/extension units

#syz fix:
ALSA: usb-audio: Fix incorrect size check for processing/extension units

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