media: mxl111sf: change mutex_init() location

commit 44870a9e7a3c24acbb3f888b2a7cc22c9bdf7e7f upstream.

Syzbot reported, that mxl111sf_ctrl_msg() uses uninitialized
mutex. The problem was in wrong mutex_init() location.

Previous mutex_init(&state->msg_lock) call was in ->init() function, but
dvb_usbv2_init() has this order of calls:

	dvb_usbv2_init()
	  dvb_usbv2_adapter_init()
	    dvb_usbv2_adapter_frontend_init()
	      props->frontend_attach()

	  props->init()

Since mxl111sf_* devices call mxl111sf_ctrl_msg() in ->frontend_attach()
internally we need to initialize state->msg_lock before
frontend_attach(). To achieve it, ->probe() call added to all mxl111sf_*
devices, which will simply initiaize mutex.

Reported-and-tested-by: syzbot+5ca0bf339f13c4243001@syzkaller.appspotmail.com
Fixes: 8572211842af ("[media] mxl111sf: convert to new DVB USB")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
index 7865fa0..cd5861a 100644 (file)
--- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c
+++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
@@ -931,8 +931,6 @@ static int mxl111sf_init(struct dvb_usb_device *d)
                  .len = sizeof(eeprom), .buf = eeprom },
        };
 
-       mutex_init(&state->msg_lock);
-
        ret = get_chip_info(state);
        if (mxl_fail(ret))
                pr_err("failed to get chip info during probe");
@@ -1074,6 +1072,14 @@ static int mxl111sf_get_stream_config_dvbt(struct dvb_frontend *fe,
        return 0;
 }
 
+static int mxl111sf_probe(struct dvb_usb_device *dev)
+{
+       struct mxl111sf_state *state = d_to_priv(dev);
+
+       mutex_init(&state->msg_lock);
+       return 0;
+}
+
 static struct dvb_usb_device_properties mxl111sf_props_dvbt = {
        .driver_name = KBUILD_MODNAME,
        .owner = THIS_MODULE,
@@ -1083,6 +1089,7 @@ static struct dvb_usb_device_properties mxl111sf_props_dvbt = {
        .generic_bulk_ctrl_endpoint = 0x02,
        .generic_bulk_ctrl_endpoint_response = 0x81,
 
+       .probe             = mxl111sf_probe,
        .i2c_algo          = &mxl111sf_i2c_algo,
        .frontend_attach   = mxl111sf_frontend_attach_dvbt,
        .tuner_attach      = mxl111sf_attach_tuner,
@@ -1124,6 +1131,7 @@ static struct dvb_usb_device_properties mxl111sf_props_atsc = {
        .generic_bulk_ctrl_endpoint = 0x02,
        .generic_bulk_ctrl_endpoint_response = 0x81,
 
+       .probe             = mxl111sf_probe,
        .i2c_algo          = &mxl111sf_i2c_algo,
        .frontend_attach   = mxl111sf_frontend_attach_atsc,
        .tuner_attach      = mxl111sf_attach_tuner,
@@ -1165,6 +1173,7 @@ static struct dvb_usb_device_properties mxl111sf_props_mh = {
        .generic_bulk_ctrl_endpoint = 0x02,
        .generic_bulk_ctrl_endpoint_response = 0x81,
 
+       .probe             = mxl111sf_probe,
        .i2c_algo          = &mxl111sf_i2c_algo,
        .frontend_attach   = mxl111sf_frontend_attach_mh,
        .tuner_attach      = mxl111sf_attach_tuner,
@@ -1233,6 +1242,7 @@ static struct dvb_usb_device_properties mxl111sf_props_atsc_mh = {
        .generic_bulk_ctrl_endpoint = 0x02,
        .generic_bulk_ctrl_endpoint_response = 0x81,
 
+       .probe             = mxl111sf_probe,
        .i2c_algo          = &mxl111sf_i2c_algo,
        .frontend_attach   = mxl111sf_frontend_attach_atsc_mh,
        .tuner_attach      = mxl111sf_attach_tuner,
@@ -1311,6 +1321,7 @@ static struct dvb_usb_device_properties mxl111sf_props_mercury = {
        .generic_bulk_ctrl_endpoint = 0x02,
        .generic_bulk_ctrl_endpoint_response = 0x81,
 
+       .probe             = mxl111sf_probe,
        .i2c_algo          = &mxl111sf_i2c_algo,
        .frontend_attach   = mxl111sf_frontend_attach_mercury,
        .tuner_attach      = mxl111sf_attach_tuner,
@@ -1381,6 +1392,7 @@ static struct dvb_usb_device_properties mxl111sf_props_mercury_mh = {
        .generic_bulk_ctrl_endpoint = 0x02,
        .generic_bulk_ctrl_endpoint_response = 0x81,
 
+       .probe             = mxl111sf_probe,
        .i2c_algo          = &mxl111sf_i2c_algo,
        .frontend_attach   = mxl111sf_frontend_attach_mercury_mh,
        .tuner_attach      = mxl111sf_attach_tuner,