USB: serial: qcserial: fix altsetting probing
Subsystems (2)
Johan Hovold
maintainerPATCH 1/1 USB: serial: qcserial: fix altsetting probing
Drivers should not assume that interface descriptors have been parsed in any particular order so use the interface number to look up the second alternate setting. That number is also what the driver later use to switch setting.
Note that although the driver could end up verifying the existence of the expected endpoints on the wrong interface, a later sanity check in usb_wwan_port_probe() would have caught this before it could cause any real damage.
--- drivers/usb/serial/qcserial.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/usb/serial/qcserial.c +2 -2
@@ -243,11 +243,11 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)/* QDL mode */ /* Gobi 2000 has a single altsetting, older ones have two */ if (serial->interface->num_altsetting ==2 ) - intf = &serial->interface->altsetting[1 ]; + intf =usb_altnum_to_altsetting (serial->interface,1 );else if (serial->interface->num_altsetting >2 ) goto done; -if (intf->desc.bNumEndpoints ==2 && +if (intf && intf->desc.bNumEndpoints ==2 &&usb_endpoint_is_bulk_in (&intf->endpoint[0 ].desc) &&usb_endpoint_is_bulk_out (&intf->endpoint[1 ].desc)) {dev_dbg (dev,"QDL port found\n" );
Signature · 1 line
2.26.2
Quoted 5 lines · Johan Hovold
Drivers should not assume that interface descriptors have been parsed in any particular order so use the interface number to look up the second alternate setting. That number is also what the driver later use to switch setting.
Quoted 7 lines
Note that although the driver could end up verifying the existence of the expected endpoints on the wrong interface, a later sanity check in
usb_wwan_port_probe()would have caught this before it could cause any real damage.Fixes a78b42824dd7 ("USB: serial: add qualcomm wireless modem driver")Signed-off-by Johan Hovold <[email protected]>