* KASAN: slab-out-of-bounds Read in build_audio_procunit
@ 2019-10-22 14:54 syzbot
2019-10-22 15:45 ` Takashi Iwai
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2019-10-22 14:54 UTC (permalink / raw)
To: alsa-devel, andreyknvl, benquike, dan.carpenter, g, linux-kernel,
linux-usb, perex, rfontana, syzkaller-bugs, tiwai, yuehaibing
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=103893cf600000
kernel config: https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5
dashboard link: https://syzkaller.appspot.com/bug?extid=0620f79a1978b1133fd7
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fd6a40e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1033215f600000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+0620f79a1978b1133fd7@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: slab-out-of-bounds in uac_processing_unit_iProcessing
include/uapi/linux/usb/audio.h:429 [inline]
BUG: KASAN: slab-out-of-bounds in build_audio_procunit+0x1306/0x13f0
sound/usb/mixer.c:2436
Read of size 1 at addr ffff8881d537c7b7 by task kworker/0:2/101
CPU: 0 PID: 101 Comm: kworker/0:2 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_processing_unit_iProcessing include/uapi/linux/usb/audio.h:429 [inline]
build_audio_procunit+0x1306/0x13f0 sound/usb/mixer.c:2436
parse_audio_processing_unit sound/usb/mixer.c:2468 [inline]
parse_audio_unit+0x17e9/0x36f0 sound/usb/mixer.c:2757
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 101:
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+0x314/0x3050 drivers/usb/core/config.c:857
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 17:
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
get_port_status drivers/usb/core/hub.c:569 [inline]
hub_ext_port_status+0x125/0x460 drivers/usb/core/hub.c:586
hub_port_status drivers/usb/core/hub.c:608 [inline]
hub_activate+0x497/0x1570 drivers/usb/core/hub.c:1111
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 ffff8881d537c700
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 183 bytes inside of
192-byte region [ffff8881d537c700, ffff8881d537c7c0)
The buggy address belongs to the page:
page:ffffea000754df00 refcount:1 mapcount:0 mapping:ffff8881da002a00
index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 ffffea000754d680 0000000600000006 ffff8881da002a00
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881d537c680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8881d537c700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8881d537c780: 00 00 00 02 fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881d537c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d537c880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
---
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@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
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: KASAN: slab-out-of-bounds Read in build_audio_procunit
2019-10-22 14:54 KASAN: slab-out-of-bounds Read in build_audio_procunit syzbot
@ 2019-10-22 15:45 ` Takashi Iwai
2019-10-28 14:34 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Takashi Iwai @ 2019-10-22 15:45 UTC (permalink / raw)
To: syzbot
Cc: alsa-devel, andreyknvl, benquike, dan.carpenter, g, linux-kernel,
linux-usb, perex, rfontana, syzkaller-bugs, tiwai, yuehaibing
On Tue, 22 Oct 2019 16:54:07 +0200,
syzbot wrote:
>
> 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=103893cf600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5
> dashboard link: https://syzkaller.appspot.com/bug?extid=0620f79a1978b1133fd7
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fd6a40e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1033215f600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+0620f79a1978b1133fd7@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: slab-out-of-bounds in uac_processing_unit_iProcessing
> include/uapi/linux/usb/audio.h:429 [inline]
> BUG: KASAN: slab-out-of-bounds in build_audio_procunit+0x1306/0x13f0
> sound/usb/mixer.c:2436
> Read of size 1 at addr ffff8881d537c7b7 by task kworker/0:2/101
>
> CPU: 0 PID: 101 Comm: kworker/0:2 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_processing_unit_iProcessing include/uapi/linux/usb/audio.h:429 [inline]
> build_audio_procunit+0x1306/0x13f0 sound/usb/mixer.c:2436
> parse_audio_processing_unit sound/usb/mixer.c:2468 [inline]
> parse_audio_unit+0x17e9/0x36f0 sound/usb/mixer.c:2757
> 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
Damn, there was a silly copy&paste error in the validation code.
The fix patch is below. I'm going to queue this for the next pull
request for 5.4.
thanks,
Takashi
-- 8< --
From: Takashi Iwai <tiwai@suse.de>
Subject: [PATCH] ALSA: usb-audio: Fix copy&paste error in the validator
The recently introduced USB-audio descriptor validator had a stupid
copy&paste error that may lead to an unexpected overlook of too short
descriptors for processing and extension units. It's likely the cause
of the report triggered by syzkaller fuzzer. Let's fix it.
Fixes: 57f8770620e9 ("ALSA: usb-audio: More validations of descriptor units")
Reported-by: syzbot+0620f79a1978b1133fd7@syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/usb/validate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/validate.c b/sound/usb/validate.c
index 3c8f73a0eb12..a5e584b60dcd 100644
--- a/sound/usb/validate.c
+++ b/sound/usb/validate.c
@@ -75,7 +75,7 @@ static bool validate_processing_unit(const void *p,
if (d->bLength < sizeof(*d))
return false;
- len = d->bLength < sizeof(*d) + d->bNrInPins;
+ len = sizeof(*d) + d->bNrInPins;
if (d->bLength < len)
return false;
switch (v->protocol) {
--
2.16.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: KASAN: slab-out-of-bounds Read in build_audio_procunit
2019-10-22 15:45 ` Takashi Iwai
@ 2019-10-28 14:34 ` Dan Carpenter
2019-10-28 14:42 ` Takashi Iwai
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2019-10-28 14:34 UTC (permalink / raw)
To: Takashi Iwai
Cc: syzbot, alsa-devel, andreyknvl, benquike, g, linux-kernel,
linux-usb, perex, rfontana, syzkaller-bugs, tiwai, yuehaibing
I wish that this could have been detected with static analysis...
On Tue, Oct 22, 2019 at 05:45:14PM +0200, Takashi Iwai wrote:
> diff --git a/sound/usb/validate.c b/sound/usb/validate.c
> index 3c8f73a0eb12..a5e584b60dcd 100644
> --- a/sound/usb/validate.c
> +++ b/sound/usb/validate.c
> @@ -75,7 +75,7 @@ static bool validate_processing_unit(const void *p,
>
> if (d->bLength < sizeof(*d))
^^^^^^^^^^^^^^^^^^^^^^^
So we know that d->bLength is >= 10.
> return false;
> - len = d->bLength < sizeof(*d) + d->bNrInPins;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Len is 1 or 0.
> + len = sizeof(*d) + d->bNrInPins;
> if (d->bLength < len)
^^^^^^^^^^^^^^^^
So this condition can't be false.
> return false;
But it just makes this return into dead code and we have a lot of dead
code paths in the kernel so it doesn't make sense to generate a warning.
... I don't know if I have a solution.
Maybe some day we will have a vim pluggin which will highlight all the
dead paths and someone would notice that it that way.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: KASAN: slab-out-of-bounds Read in build_audio_procunit
2019-10-28 14:34 ` Dan Carpenter
@ 2019-10-28 14:42 ` Takashi Iwai
0 siblings, 0 replies; 4+ messages in thread
From: Takashi Iwai @ 2019-10-28 14:42 UTC (permalink / raw)
To: Dan Carpenter
Cc: syzbot, alsa-devel, andreyknvl, benquike, g, linux-kernel,
linux-usb, perex, rfontana, syzkaller-bugs, tiwai, yuehaibing
On Mon, 28 Oct 2019 15:34:06 +0100,
Dan Carpenter wrote:
>
> I wish that this could have been detected with static analysis...
>
> On Tue, Oct 22, 2019 at 05:45:14PM +0200, Takashi Iwai wrote:
> > diff --git a/sound/usb/validate.c b/sound/usb/validate.c
> > index 3c8f73a0eb12..a5e584b60dcd 100644
> > --- a/sound/usb/validate.c
> > +++ b/sound/usb/validate.c
> > @@ -75,7 +75,7 @@ static bool validate_processing_unit(const void *p,
> >
> > if (d->bLength < sizeof(*d))
> ^^^^^^^^^^^^^^^^^^^^^^^
> So we know that d->bLength is >= 10.
>
> > return false;
> > - len = d->bLength < sizeof(*d) + d->bNrInPins;
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Len is 1 or 0.
>
> > + len = sizeof(*d) + d->bNrInPins;
> > if (d->bLength < len)
> ^^^^^^^^^^^^^^^^
>
> So this condition can't be false.
>
> > return false;
>
> But it just makes this return into dead code and we have a lot of dead
> code paths in the kernel so it doesn't make sense to generate a warning.
> ... I don't know if I have a solution.
>
> Maybe some day we will have a vim pluggin which will highlight all the
> dead paths and someone would notice that it that way.
That'd be awesome :) Of even a simple checker code that can run in
the git commit hook should suffice for careless maintainers like me.
thanks,
Takashi
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-10-28 14:42 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-10-22 14:54 KASAN: slab-out-of-bounds Read in build_audio_procunit syzbot
2019-10-22 15:45 ` Takashi Iwai
2019-10-28 14:34 ` Dan Carpenter
2019-10-28 14:42 ` Takashi Iwai
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