general protection fault in pk_probe

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: eea39f24 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=14c3589e600000
kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
dashboard link: https://syzkaller.appspot.com/bug?extid=1088533649dafa1c9004
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1667cc66600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f30dbc600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+108853...@syzkaller.appspotmail.com

prodikeys 0003:041E:2801.0001: unknown main item tag 0x0
prodikeys 0003:041E:2801.0001: unknown main item tag 0x0
prodikeys 0003:041E:2801.0001: hidraw0: USB HID v0.00 Device [HID
041e:2801] on usb-dummy_hcd.0-1/input1
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc5+ #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
RIP: 0010:pcmidi_submit_output_report drivers/hid/hid-prodikeys.c:300
[inline]
RIP: 0010:pcmidi_set_operational drivers/hid/hid-prodikeys.c:558 [inline]
RIP: 0010:pcmidi_snd_initialise drivers/hid/hid-prodikeys.c:686 [inline]
RIP: 0010:pk_probe+0xb51/0xfd0 drivers/hid/hid-prodikeys.c:836
Code: 0f 85 50 04 00 00 48 8b 04 24 4c 89 7d 10 48 8b 58 08 e8 b2 53 e4 fc
48 8b 54 24 20 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f
85 13 04 00 00 48 ba 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff8881da20ee10 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8881d2d40000 RCX: ffffffff8459833e
RDX: 0000000000000006 RSI: ffffffff8459862e RDI: ffff8881d2aee610
RBP: ffff8881d2aee600 R08: ffff8881da1f9800 R09: ffffed103b64677c
R10: ffffed103b64677b R11: ffff8881db233bdb R12: ffff8881d2d40000
R13: 0000000000000000 R14: ffff8881d4ec4ab0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2fc6afa518 CR3: 00000001d099d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
hid_device_probe+0x2be/0x3f0 drivers/hid/hid-core.c:2209
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 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:454
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2165
hid_add_device+0x33c/0x990 drivers/hid/hid-core.c:2365
usbhid_probe+0xa81/0xfa0 drivers/hid/usbhid/hid-core.c:1386
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 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:454
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2165
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+0x101/0x1b0 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:454
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2165
usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
hub_port_connect drivers/usb/core/hub.c:5098 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
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
Modules linked in:
---[ end trace 57a1aecde3464295 ]---
RIP: 0010:pcmidi_submit_output_report drivers/hid/hid-prodikeys.c:300
[inline]
RIP: 0010:pcmidi_set_operational drivers/hid/hid-prodikeys.c:558 [inline]
RIP: 0010:pcmidi_snd_initialise drivers/hid/hid-prodikeys.c:686 [inline]
RIP: 0010:pk_probe+0xb51/0xfd0 drivers/hid/hid-prodikeys.c:836
Code: 0f 85 50 04 00 00 48 8b 04 24 4c 89 7d 10 48 8b 58 08 e8 b2 53 e4 fc
48 8b 54 24 20 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f
85 13 04 00 00 48 ba 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff8881da20ee10 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8881d2d40000 RCX: ffffffff8459833e
RDX: 0000000000000006 RSI: ffffffff8459862e RDI: ffff8881d2aee610
RBP: ffff8881d2aee600 R08: ffff8881da1f9800 R09: ffffed103b64677c
R10: ffffed103b64677b R11: ffff8881db233bdb R12: ffff8881d2d40000
R13: 0000000000000000 R14: ffff8881d4ec4ab0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2fc6afa518 CR3: 00000001d099d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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 syzk...@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

[Alan Stern]

The reason for this bug seems pretty clear: pcmidi_get_output_report()
can return an error, but pcmidi_set_operational() doesn't bother to
check the return code.

Alan Stern

#syz test: https://github.com/google/kasan.git eea39f24

Index: usb-devel/drivers/hid/hid-prodikeys.c
===================================================================
--- usb-devel.orig/drivers/hid/hid-prodikeys.c
+++ usb-devel/drivers/hid/hid-prodikeys.c
@@ -551,10 +551,14 @@ static void pcmidi_setup_extra_keys(

static int pcmidi_set_operational(struct pcmidi_snd *pm)
{
+ int rc;
+
if (pm->ifnum != 1)
return 0; /* only set up ONCE for interace 1 */

- pcmidi_get_output_report(pm);
+ rc = pcmidi_get_output_report(pm);
+ if (rc < 0)
+ return rc;
pcmidi_submit_output_report(pm, 0xc1);
return 0;
}
@@ -683,7 +687,11 @@ static int pcmidi_snd_initialise(struct
spin_lock_init(&pm->rawmidi_in_lock);

init_sustain_timers(pm);
- pcmidi_set_operational(pm);
+ err = pcmidi_set_operational(pm);
+ if (err < 0) {
+ pk_error("failed to find output report\n");
+ goto fail_register;
+ }

/* register it */
err = snd_card_register(card);

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+108853...@syzkaller.appspotmail.com

Tested on:

commit: eea39f24 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git

kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
dashboard link: https://syzkaller.appspot.com/bug?extid=1088533649dafa1c9004
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=139bc892600000

Note: testing is done by a robot and is best-effort only.

[Hillf Danton]

Date: Tue, 03 Sep 2019 05:08:10 -0700

> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: eea39f24 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=14c3589e600000

> kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
> dashboard link: https://syzkaller.appspot.com/bug?extid=1088533649dafa1c9004
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)

> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1667cc66600000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f30dbc600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+108853...@syzkaller.appspotmail.com
>
> prodikeys 0003:041E:2801.0001: unknown main item tag 0x0
> prodikeys 0003:041E:2801.0001: unknown main item tag 0x0
> prodikeys 0003:041E:2801.0001: hidraw0: USB HID v0.00 Device [HID
> 041e:2801] on usb-dummy_hcd.0-1/input1
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] SMP KASAN
> CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc5+ #28
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Workqueue: usb_hub_wq hub_event
> RIP: 0010:pcmidi_submit_output_report drivers/hid/hid-prodikeys.c:300 [inline]
> RIP: 0010:pcmidi_set_operational drivers/hid/hid-prodikeys.c:558 [inline]
> RIP: 0010:pcmidi_snd_initialise drivers/hid/hid-prodikeys.c:686 [inline]
> RIP: 0010:pk_probe+0xb51/0xfd0 drivers/hid/hid-prodikeys.c:836

Submit output report unless error.

--- a/drivers/hid/hid-prodikeys.c
+++ b/drivers/hid/hid-prodikeys.c

@@ -551,10 +551,14 @@ static void pcmidi_setup_extra_keys(

static int pcmidi_set_operational(struct pcmidi_snd *pm)
{

+ int err;

+
if (pm->ifnum != 1)
return 0; /* only set up ONCE for interace 1 */

- pcmidi_get_output_report(pm);

+ err = pcmidi_get_output_report(pm);
+ if (err)
+ return err;
pcmidi_submit_output_report(pm, 0xc1);
return 0;
}
--

[Alan Stern]

The syzbot fuzzer provoked a general protection fault in the
hid-prodikeys driver:

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc5+ #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
RIP: 0010:pcmidi_submit_output_report drivers/hid/hid-prodikeys.c:300 [inline]
RIP: 0010:pcmidi_set_operational drivers/hid/hid-prodikeys.c:558 [inline]
RIP: 0010:pcmidi_snd_initialise drivers/hid/hid-prodikeys.c:686 [inline]
RIP: 0010:pk_probe+0xb51/0xfd0 drivers/hid/hid-prodikeys.c:836
Code: 0f 85 50 04 00 00 48 8b 04 24 4c 89 7d 10 48 8b 58 08 e8 b2 53 e4 fc
48 8b 54 24 20 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f
85 13 04 00 00 48 ba 00 00 00 00 00 fc ff df 49 8b

The problem is caused by the fact that pcmidi_get_output_report() will
return an error if the HID device doesn't provide the right sort of
output report, but pcmidi_set_operational() doesn't bother to check
the return code and assumes the function call always succeeds.

This patch adds the missing check and aborts the probe operation if
necessary.

Reported-and-tested-by: syzbot+108853...@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
CC: <sta...@vger.kernel.org>

---


[as1911]


drivers/hid/hid-prodikeys.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

Index: usb-devel/drivers/hid/hid-prodikeys.c
===================================================================
--- usb-devel.orig/drivers/hid/hid-prodikeys.c
+++ usb-devel/drivers/hid/hid-prodikeys.c

@@ -551,10 +551,14 @@ static void pcmidi_setup_extra_keys(

static int pcmidi_set_operational(struct pcmidi_snd *pm)
{

+ int rc;

+
if (pm->ifnum != 1)
return 0; /* only set up ONCE for interace 1 */

- pcmidi_get_output_report(pm);

[Jiri Kosina]

Applied, thanks a lot Alan.

--
Jiri Kosina
SUSE Labs