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Commit fd5054c1 authored by Erik Slagter's avatar Erik Slagter Committed by Greg Kroah-Hartman
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USB: cdc_acm: Fix oops when Droids MuIn LCD is connected 



The Droids MuIn LCD operates like a serial remote terminal.
Data received are displayed directly on the LCD. This patch
fixes the kernel null pointer oops when it is plugged in.

Add NO_DATA_INTERFACE quirk to tell the driver that "control"
and "data" interfaces are not separated for this device, which
prevents dereferencing a null pointer in the device probe code.

Signed-off-by: default avatarErik Slagter <erik@slagter.name>
Signed-off-by: default avatarMaxin B. John <maxin.john@gmail.com>
Tested-by: default avatarErik Slagter <erik@slagter.name>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a9df304c

drivers/usb/class/cdc-acm.c

+11 −2
Original line number Diff line number Diff line
@@ -853,7 +853,7 @@ static int acm_probe(struct usb_interface *intf, 
	u8 ac_management_function = 0;

	u8 call_management_function = 0;

	int call_interface_num = -1;

	int data_interface_num;

	int data_interface_num = -1;

	unsigned long quirks;

	int num_rx_buf;

	int i;
@@ -937,6 +937,10 @@ static int acm_probe(struct usb_interface *intf, 
	if (!union_header) {

		if (call_interface_num > 0) {

			dev_dbg(&intf->dev, "No union descriptor, using call management descriptor\n");

			/* quirks for Droids MuIn LCD */

			if (quirks & NO_DATA_INTERFACE)

				data_interface = usb_ifnum_to_if(usb_dev, 0);

			else

				data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = call_interface_num));

			control_interface = intf;

		} else {
@@ -1535,6 +1539,11 @@ static const struct usb_device_id acm_ids[] = { 
	.driver_info = NOT_A_MODEM,

	},



	/* Support for Droids MuIn LCD */

	{ USB_DEVICE(0x04d8, 0x000b),

	.driver_info = NO_DATA_INTERFACE,

	},



	/* control interfaces without any protocol set */

	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,

		USB_CDC_PROTO_NONE) },

drivers/usb/class/cdc-acm.h

+1 −0
Original line number Diff line number Diff line
@@ -126,3 +126,4 @@ struct acm { 
#define SINGLE_RX_URB			2

#define NO_CAP_LINE			4

#define NOT_A_MODEM			8

#define NO_DATA_INTERFACE		16