3.16.79-rc1 review patch. If anyone has any objections, please let me know.
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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 Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Ben Hutchings ben@decadent.org.uk --- 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 @@ -557,10 +557,14 @@ 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; } @@ -689,7 +693,11 @@ 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);