static int cxusb_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[],
			  int num)
{
	struct dvb_usb_device *d = i2c_get_adapdata(adap);
	int ret;
	int i;

	if (mutex_lock_interruptible(&d->i2c_mutex) < 0)
		return -EAGAIN;

	for (i = 0; i < num; i++) {

		if (le16_to_cpu(d->udev->descriptor.idVendor) == USB_VID_MEDION)
			switch (msg[i].addr) {
			case 0x63:
				cxusb_gpio_tuner(d, 0);
				break;
			default:
				cxusb_gpio_tuner(d, 1);
				break;
			}

		if (msg[i].flags & I2C_M_RD) {
			/* read only */
			u8 obuf[3], ibuf[MAX_XFER_SIZE];

			if (1 + msg[i].len > sizeof(ibuf)) {
				warn("i2c rd: len=%d is too big!\n",
				     msg[i].len);
				ret = -EOPNOTSUPP;
				goto unlock;
			}
			obuf[0] = 0;
			obuf[1] = msg[i].len;
			obuf[2] = msg[i].addr;
			if (cxusb_ctrl_msg(d, CMD_I2C_READ,
					   obuf, 3,
					   ibuf, 1+msg[i].len) < 0) {
				warn("i2c read failed");
				break;
			}
			memcpy(msg[i].buf, &ibuf[1], msg[i].len);
		} else if (i+1 < num && (msg[i+1].flags & I2C_M_RD) &&
			   msg[i].addr == msg[i+1].addr) {
			/* write to then read from same address */
			u8 obuf[MAX_XFER_SIZE], ibuf[MAX_XFER_SIZE];

			if (3 + msg[i].len > sizeof(obuf)) {
				warn("i2c wr: len=%d is too big!\n",
				     msg[i].len);
				ret = -EOPNOTSUPP;
				goto unlock;
			}
			if (1 + msg[i + 1].len > sizeof(ibuf)) {
				warn("i2c rd: len=%d is too big!\n",
				     msg[i + 1].len);
				ret = -EOPNOTSUPP;
				goto unlock;
			}
			obuf[0] = msg[i].len;
			obuf[1] = msg[i+1].len;
			obuf[2] = msg[i].addr;
			memcpy(&obuf[3], msg[i].buf, msg[i].len);

			if (cxusb_ctrl_msg(d, CMD_I2C_READ,
					   obuf, 3+msg[i].len,
					   ibuf, 1+msg[i+1].len) < 0)
				break;

			if (ibuf[0] != 0x08)
				deb_i2c("i2c read may have failed\n");

			memcpy(msg[i+1].buf, &ibuf[1], msg[i+1].len);

			i++;
		} else {
			/* write only */
			u8 obuf[MAX_XFER_SIZE], ibuf;

			if (2 + msg[i].len > sizeof(obuf)) {
				warn("i2c wr: len=%d is too big!\n",
				     msg[i].len);
				ret = -EOPNOTSUPP;
				goto unlock;
			}
			obuf[0] = msg[i].addr;
			obuf[1] = msg[i].len;
			memcpy(&obuf[2], msg[i].buf, msg[i].len);

			if (cxusb_ctrl_msg(d, CMD_I2C_WRITE, obuf,
					   2+msg[i].len, &ibuf,1) < 0)
				break;
			if (ibuf != 0x08)
				deb_i2c("i2c write may have failed\n");
		}
	}

	if (i == num)
		ret = num;
	else
		ret = -EREMOTEIO;

unlock:
	mutex_unlock(&d->i2c_mutex);
	return ret;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.