syzbot reported null pointer dereference in usb_audio_probe.
The problem was in case, when quirk == NULL. It's not an
error condition, so quirk must be checked before dereferencing.
Call Trace:
usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396
really_probe+0x291/0xe60 drivers/base/dd.c:554
driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846
bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
__device_attach+0x228/0x4a0 drivers/base/dd.c:914
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0xbdb/0x1db0 drivers/base/core.c:3242
usb_set_configuration+0x113f/0x1910 drivers/usb/core/message.c:2164
usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238
usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293
really_probe+0x291/0xe60 drivers/base/dd.c:554
driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740
__device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846
bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
__device_attach+0x228/0x4a0 drivers/base/dd.c:914
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
device_add+0xbdb/0x1db0 drivers/base/core.c:3242
usb_new_device.cold+0x721/0x1058 drivers/usb/core/hub.c:2555
hub_port_connect drivers/usb/core/hub.c:5223 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
port_event drivers/usb/core/hub.c:5509 [inline]
hub_event+0x2357/0x4320 drivers/usb/core/hub.c:5591
process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
kthread+0x3b1/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Reported-by: syzbot+719da9b149a931f5143f@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
---
sound/usb/card.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 08c794883299..3fd1743513b5 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -830,7 +830,8 @@ static int usb_audio_probe(struct usb_interface *intf,
snd_media_device_create(chip, intf);
}
- chip->quirk_type = quirk->type;
+ if (quirk)
+ chip->quirk_type = quirk->type;
usb_chip[chip->index] = chip;
chip->intf[chip->num_interfaces] = intf;
--
2.25.1
