From: Pavel Skripkin paskripkin@gmail.com

stable inclusion from stable-v4.19.222 commit 4b2d9600b31f9ba7adbc9f3c54a068615d27b390 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6SIB CVE: CVE-2021-47583

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

--------------------------------

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 Signed-off-by: Liu Shixin liushixin2@huawei.com --- drivers/media/usb/dvb-usb-v2/mxl111sf.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c index 4713ba65e1c2..da2f282b1b3c 100644 --- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c +++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c @@ -932,8 +932,6 @@ 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"); @@ -1075,6 +1073,14 @@ 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, @@ -1084,6 +1090,7 @@ 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, @@ -1125,6 +1132,7 @@ 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, @@ -1166,6 +1174,7 @@ 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, @@ -1234,6 +1243,7 @@ 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, @@ -1312,6 +1322,7 @@ 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, @@ -1382,6 +1393,7 @@ 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,