| From 98375b86c79137416e9fd354177b85e768c16e56 Mon Sep 17 00:00:00 2001 |
| From: Alan Stern <stern@rowland.harvard.edu> |
| Date: Wed, 4 Sep 2019 11:54:20 -0400 |
| Subject: HID: prodikeys: Fix general protection fault during probe |
| |
| From: Alan Stern <stern@rowland.harvard.edu> |
| |
| commit 98375b86c79137416e9fd354177b85e768c16e56 upstream. |
| |
| 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+1088533649dafa1c9004@syzkaller.appspotmail.com |
| Signed-off-by: Alan Stern <stern@rowland.harvard.edu> |
| CC: <stable@vger.kernel.org> |
| Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/hid/hid-prodikeys.c | 12 ++++++++++-- |
| 1 file changed, 10 insertions(+), 2 deletions(-) |
| |
| --- 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 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); |