Re: [PATCH] media: dw2102: Fix use after free

Sean Young
2020-04-14T10:10:39Z

On Thu, Aug 29, 2019 at 09:56:04AM -0700, Kees Cook wrote:
> On Thu, Aug 22, 2019 at 01:41:47PM +0300, Anton Vasilyev wrote:
> > dvb_usb_device_init stores parts of properties at d->props
> > and d->desc and uses it on dvb_usb_device_exit.
> > Free of properties on module probe leads to use after free.
> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204597
> >
> > The patch makes properties static instead of allocated on heap to prevent
> > memleak and use after free.
> > Also fixes s421_properties.devices initialization to have 2 element
> > instead of 6 copied from p7500_properties.
>
> Can these be const? If not, is the probe() logic safe for these globals
> when there are multiple users? (I don't know this driver, but what
> happens if two of these devices get plugged in, for example.)

Sorry for the super-late review.

So this is exactly right. dvb_usb_device_init() copies the properties,
so that is fine (I've just written a patch to make the props argument
const*).

However, this code changes the properties based on the usb id. See here:

https://github.com/torvalds/linux/blob/master/drivers/media/usb/dvb-usb/dw2102.c#L1900-L1916

So, these different variants need to be split into two or something like that.

Sean

>
> -Kees
>
> >
> >
> > Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
> > Fixes: 299c7007e936 ("media: dw2102: Fix memleak on sequence of probes")
> > ---
> > drivers/media/usb/dvb-usb/dw2102.c | 338 ++++++++++++++++++-----------
> > 1 file changed, 215 insertions(+), 123 deletions(-)
> >
> > diff --git a/drivers/media/usb/dvb-usb/dw2102.c b/drivers/media/usb/dvb-usb/dw2102.c
> > index b960abd00d48..7ea3aa0fee40 100644
> > --- a/drivers/media/usb/dvb-usb/dw2102.c
> > +++ b/drivers/media/usb/dvb-usb/dw2102.c
> > @@ -2098,46 +2098,153 @@ static struct dvb_usb_device_properties s6x0_properties = {
> > }
> > };
> >
> > -static const struct dvb_usb_device_description d1100 = {
> > - "Prof 1100 USB ",
> > - {&dw2102_table[PROF_1100], NULL},
> > - {NULL},
> > -};
> > +static struct dvb_usb_device_properties p1100_properties = {
> > + .caps = DVB_USB_IS_AN_I2C_ADAPTER,
> > + .usb_ctrl = DEVICE_SPECIFIC,
> > + .size_of_priv = sizeof(struct dw2102_state),
> > + .firmware = P1100_FIRMWARE,
> > + .no_reconnect = 1,
> >
> > -static const struct dvb_usb_device_description d660 = {
> > - "TeVii S660 USB",
> > - {&dw2102_table[TEVII_S660], NULL},
> > - {NULL},
> > -};
> > + .i2c_algo = &s6x0_i2c_algo,
> > + .rc.core = {
> > + .rc_interval = 150,
> > + .rc_codes = RC_MAP_TBS_NEC,
> > + .module_name = "dw2102",
> > + .allowed_protos = RC_PROTO_BIT_NEC,
> > + .rc_query = prof_rc_query,
> > + },
> >
> > -static const struct dvb_usb_device_description d480_1 = {
> > - "TeVii S480.1 USB",
> > - {&dw2102_table[TEVII_S480_1], NULL},
> > - {NULL},
> > + .generic_bulk_ctrl_endpoint = 0x81,
> > + .num_adapters = 1,
> > + .download_firmware = dw2102_load_firmware,
> > + .read_mac_address = s6x0_read_mac_address,
> > + .adapter = {
> > + {
> > + .num_frontends = 1,
> > + .fe = {{
> > + .frontend_attach = stv0288_frontend_attach,
> > + .stream = {
> > + .type = USB_BULK,
> > + .count = 8,
> > + .endpoint = 0x82,
> > + .u = {
> > + .bulk = {
> > + .buffersize = 4096,
> > + }
> > + }
> > + },
> > + } },
> > + }
> > + },
> > + .num_device_descs = 1,
> > + .devices = {
> > + {"Prof 1100 USB ",
> > + {&dw2102_table[PROF_1100], NULL},
> > + {NULL},
> > + },
> > + }
> > };
> >
> > -static const struct dvb_usb_device_description d480_2 = {
> > - "TeVii S480.2 USB",
> > - {&dw2102_table[TEVII_S480_2], NULL},
> > - {NULL},
> > -};
> > +static struct dvb_usb_device_properties s660_properties = {
> > + .caps = DVB_USB_IS_AN_I2C_ADAPTER,
> > + .usb_ctrl = DEVICE_SPECIFIC,
> > + .size_of_priv = sizeof(struct dw2102_state),
> > + .firmware = S660_FIRMWARE,
> > + .no_reconnect = 1,
> >
> > -static const struct dvb_usb_device_description d7500 = {
> > - "Prof 7500 USB DVB-S2",
> > - {&dw2102_table[PROF_7500], NULL},
> > - {NULL},
> > -};
> > + .i2c_algo = &s6x0_i2c_algo,
> > + .rc.core = {
> > + .rc_interval = 150,
> > + .rc_codes = RC_MAP_TEVII_NEC,
> > + .module_name = "dw2102",
> > + .allowed_protos = RC_PROTO_BIT_NEC,
> > + .rc_query = dw2102_rc_query,
> > + },
> >
> > -static const struct dvb_usb_device_description d421 = {
> > - "TeVii S421 PCI",
> > - {&dw2102_table[TEVII_S421], NULL},
> > - {NULL},
> > + .generic_bulk_ctrl_endpoint = 0x81,
> > + .num_adapters = 1,
> > + .download_firmware = dw2102_load_firmware,
> > + .read_mac_address = s6x0_read_mac_address,
> > + .adapter = {
> > + {
> > + .num_frontends = 1,
> > + .fe = {{
> > + .frontend_attach = ds3000_frontend_attach,
> > + .stream = {
> > + .type = USB_BULK,
> > + .count = 8,
> > + .endpoint = 0x82,
> > + .u = {
> > + .bulk = {
> > + .buffersize = 4096,
> > + }
> > + }
> > + },
> > + } },
> > + }
> > + },
> > + .num_device_descs = 3,
> > + .devices = {
> > + {"TeVii S660 USB",
> > + {&dw2102_table[TEVII_S660], NULL},
> > + {NULL},
> > + },
> > + {"TeVii S480.1 USB",
> > + {&dw2102_table[TEVII_S480_1], NULL},
> > + {NULL},
> > + },
> > + {"TeVii S480.2 USB",
> > + {&dw2102_table[TEVII_S480_2], NULL},
> > + {NULL},
> > + },
> > + }
> > };
> >
> > -static const struct dvb_usb_device_description d632 = {
> > - "TeVii S632 USB",
> > - {&dw2102_table[TEVII_S632], NULL},
> > - {NULL},
> > +static struct dvb_usb_device_properties p7500_properties = {
> > + .caps = DVB_USB_IS_AN_I2C_ADAPTER,
> > + .usb_ctrl = DEVICE_SPECIFIC,
> > + .size_of_priv = sizeof(struct dw2102_state),
> > + .firmware = P7500_FIRMWARE,
> > + .no_reconnect = 1,
> > +
> > + .i2c_algo = &s6x0_i2c_algo,
> > + .rc.core = {
> > + .rc_interval = 150,
> > + .rc_codes = RC_MAP_TBS_NEC,
> > + .module_name = "dw2102",
> > + .allowed_protos = RC_PROTO_BIT_NEC,
> > + .rc_query = prof_rc_query,
> > + },
> > +
> > + .generic_bulk_ctrl_endpoint = 0x81,
> > + .num_adapters = 1,
> > + .download_firmware = dw2102_load_firmware,
> > + .read_mac_address = s6x0_read_mac_address,
> > + .adapter = {
> > + {
> > + .num_frontends = 1,
> > + .fe = {{
> > + .frontend_attach = prof_7500_frontend_attach,
> > + .stream = {
> > + .type = USB_BULK,
> > + .count = 8,
> > + .endpoint = 0x82,
> > + .u = {
> > + .bulk = {
> > + .buffersize = 4096,
> > + }
> > + }
> > + },
> > + } },
> > + }
> > + },
> > + .num_device_descs = 1,
> > + .devices = {
> > + {"Prof 7500 USB DVB-S2",
> > + {&dw2102_table[PROF_7500], NULL},
> > + {NULL},
> > + },
> > + }
> > };
> >
> > static struct dvb_usb_device_properties su3000_properties = {
> > @@ -2209,6 +2316,59 @@ static struct dvb_usb_device_properties su3000_properties = {
> > }
> > };
> >
> > +static struct dvb_usb_device_properties s421_properties = {
> > + .caps = DVB_USB_IS_AN_I2C_ADAPTER,
> > + .usb_ctrl = DEVICE_SPECIFIC,
> > + .size_of_priv = sizeof(struct dw2102_state),
> > + .power_ctrl = su3000_power_ctrl,
> > + .num_adapters = 1,
> > + .identify_state = su3000_identify_state,
> > + .i2c_algo = &su3000_i2c_algo,
> > +
> > + .rc.core = {
> > + .rc_interval = 150,
> > + .rc_codes = RC_MAP_SU3000,
> > + .module_name = "dw2102",
> > + .allowed_protos = RC_PROTO_BIT_RC5,
> > + .rc_query = su3000_rc_query,
> > + },
> > +
> > + .read_mac_address = su3000_read_mac_address,
> > +
> > + .generic_bulk_ctrl_endpoint = 0x01,
> > +
> > + .adapter = {
> > + {
> > + .num_frontends = 1,
> > + .fe = {{
> > + .streaming_ctrl = su3000_streaming_ctrl,
> > + .frontend_attach = m88rs2000_frontend_attach,
> > + .stream = {
> > + .type = USB_BULK,
> > + .count = 8,
> > + .endpoint = 0x82,
> > + .u = {
> > + .bulk = {
> > + .buffersize = 4096,
> > + }
> > + }
> > + }
> > + } },
> > + }
> > + },
> > + .num_device_descs = 2,
> > + .devices = {
> > + { "TeVii S421 PCI",
> > + { &dw2102_table[TEVII_S421], NULL },
> > + { NULL },
> > + },
> > + { "TeVii S632 USB",
> > + { &dw2102_table[TEVII_S632], NULL },
> > + { NULL },
> > + },
> > + }
> > +};
> > +
> > static struct dvb_usb_device_properties t220_properties = {
> > .caps = DVB_USB_IS_AN_I2C_ADAPTER,
> > .usb_ctrl = DEVICE_SPECIFIC,
> > @@ -2326,101 +2486,33 @@ static struct dvb_usb_device_properties tt_s2_4600_properties = {
> > static int dw2102_probe(struct usb_interface *intf,
> > const struct usb_device_id *id)
> > {
> > - int retval = -ENOMEM;
> > - struct dvb_usb_device_properties *p1100;
> > - struct dvb_usb_device_properties *s660;
> > - struct dvb_usb_device_properties *p7500;
> > - struct dvb_usb_device_properties *s421;
> > -
> > - p1100 = kmemdup(&s6x0_properties,
> > - sizeof(struct dvb_usb_device_properties), GFP_KERNEL);
> > - if (!p1100)
> > - goto err0;
> > -
> > - /* copy default structure */
> > - /* fill only different fields */
> > - p1100->firmware = P1100_FIRMWARE;
> > - p1100->devices[0] = d1100;
> > - p1100->rc.core.rc_query = prof_rc_query;
> > - p1100->rc.core.rc_codes = RC_MAP_TBS_NEC;
> > - p1100->adapter->fe[0].frontend_attach = stv0288_frontend_attach;
> > -
> > - s660 = kmemdup(&s6x0_properties,
> > - sizeof(struct dvb_usb_device_properties), GFP_KERNEL);
> > - if (!s660)
> > - goto err1;
> > -
> > - s660->firmware = S660_FIRMWARE;
> > - s660->num_device_descs = 3;
> > - s660->devices[0] = d660;
> > - s660->devices[1] = d480_1;
> > - s660->devices[2] = d480_2;
> > - s660->adapter->fe[0].frontend_attach = ds3000_frontend_attach;
> > -
> > - p7500 = kmemdup(&s6x0_properties,
> > - sizeof(struct dvb_usb_device_properties), GFP_KERNEL);
> > - if (!p7500)
> > - goto err2;
> > -
> > - p7500->firmware = P7500_FIRMWARE;
> > - p7500->devices[0] = d7500;
> > - p7500->rc.core.rc_query = prof_rc_query;
> > - p7500->rc.core.rc_codes = RC_MAP_TBS_NEC;
> > - p7500->adapter->fe[0].frontend_attach = prof_7500_frontend_attach;
> > -
> > -
> > - s421 = kmemdup(&su3000_properties,
> > - sizeof(struct dvb_usb_device_properties), GFP_KERNEL);
> > - if (!s421)
> > - goto err3;
> > -
> > - s421->num_device_descs = 2;
> > - s421->devices[0] = d421;
> > - s421->devices[1] = d632;
> > - s421->adapter->fe[0].frontend_attach = m88rs2000_frontend_attach;
> > -
> > - if (0 == dvb_usb_device_init(intf, &dw2102_properties,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, &dw2104_properties,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, &dw3101_properties,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, &s6x0_properties,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, p1100,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, s660,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, p7500,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, s421,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, &su3000_properties,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, &t220_properties,
> > - THIS_MODULE, NULL, adapter_nr) ||
> > - 0 == dvb_usb_device_init(intf, &tt_s2_4600_properties,
> > - THIS_MODULE, NULL, adapter_nr)) {
> > -
> > - /* clean up copied properties */
> > - kfree(s421);
> > - kfree(p7500);
> > - kfree(s660);
> > - kfree(p1100);
> > + if (!(dvb_usb_device_init(intf, &dw2102_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &dw2104_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &dw3101_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &s6x0_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &p1100_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &s660_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &p7500_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &s421_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &su3000_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &t220_properties,
> > + THIS_MODULE, NULL, adapter_nr) &&
> > + dvb_usb_device_init(intf, &tt_s2_4600_properties,
> > + THIS_MODULE, NULL, adapter_nr))) {
> >
> > return 0;
> > }
> >
> > - retval = -ENODEV;
> > - kfree(s421);
> > -err3:
> > - kfree(p7500);
> > -err2:
> > - kfree(s660);
> > -err1:
> > - kfree(p1100);
> > -err0:
> > - return retval;
> > + return -ENODEV;
> > }
> >
> > static void dw2102_disconnect(struct usb_interface *intf)
> > --
> > 2.23.0
> >
>
> --
> Kees Cook