usb_parse.c

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/* $FreeBSD$ */
/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2008-2020 Hans Petter Selasky. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
 
#ifdef USB_GLOBAL_INCLUDE_FILE
#include USB_GLOBAL_INCLUDE_FILE
#else
#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>
 
#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
 
#define USB_DEBUG_VAR usb_debug
 
#include <dev/usb/usb_core.h>
#include <dev/usb/usb_debug.h>
#endif                  /* USB_GLOBAL_INCLUDE_FILE */
 
/*------------------------------------------------------------------------*
 *      usb_desc_foreach
 *
 * This function is the safe way to iterate across the USB config
 * descriptor. It contains several checks against invalid
 * descriptors. If the "desc" argument passed to this function is
 * "NULL" the first descriptor, if any, will be returned.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: Next descriptor after "desc"
 *------------------------------------------------------------------------*/
struct usb_descriptor *
usb_desc_foreach(struct usb_config_descriptor *cd, 
    struct usb_descriptor *_desc)
{
        uint8_t *desc_next;
        uint8_t *start;
        uint8_t *end;
        uint8_t *desc;
 
        /* be NULL safe */
        if (cd == NULL)
                return (NULL);
 
        /* We assume that the "wTotalLength" has been checked. */
        start = (uint8_t *)cd;
        end = start + UGETW(cd->wTotalLength);
        desc = (uint8_t *)_desc;
 
        /* Get start of next USB descriptor. */
        if (desc == NULL)
                desc = start;
        else
                desc = desc + desc[0];
 
        /* Check that the next USB descriptor is within the range. */
        if ((desc < start) || (desc >= end))
                return (NULL);          /* out of range, or EOD */
 
        /* Check that the second next USB descriptor is within range. */
        desc_next = desc + desc[0];
        if ((desc_next < start) || (desc_next > end))
                return (NULL);          /* out of range */
 
        /* Check minimum descriptor length. */
        if (desc[0] < 3)
                return (NULL);          /* too short descriptor */
 
        /* Return start of next descriptor. */
        return ((struct usb_descriptor *)desc);
}
 
/*------------------------------------------------------------------------*
 *      usb_idesc_foreach
 *
 * This function will iterate the interface descriptors in the config
 * descriptor. The parse state structure should be zeroed before
 * calling this function the first time.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: A valid interface descriptor
 *------------------------------------------------------------------------*/
struct usb_interface_descriptor *
usb_idesc_foreach(struct usb_config_descriptor *cd,
    struct usb_idesc_parse_state *ps)
{
        struct usb_interface_descriptor *id;
        uint8_t new_iface;
 
        /* retrieve current descriptor */
        id = (struct usb_interface_descriptor *)ps->desc;
        /* default is to start a new interface */
        new_iface = 1;
 
        while (1) {
                id = (struct usb_interface_descriptor *)
                    usb_desc_foreach(cd, (struct usb_descriptor *)id);
                if (id == NULL)
                        break;
                if ((id->bDescriptorType == UDESC_INTERFACE) &&
                    (id->bLength >= sizeof(*id))) {
                        if (ps->iface_no_last == id->bInterfaceNumber) {
                                /*
                                 * Don't allow more than 256 alternate
                                 * settings to avoid overflowing the
                                 * alternate index which is a 8-bit
                                 * variable.
                                 */
                                if (ps->iface_index_alt == 255) {
                                        DPRINTF("Interface(%u) has more than 256 alternate settings\n",
                                            id->bInterfaceNumber);
                                        continue;
                                }
                                new_iface = 0;
                        }
                        ps->iface_no_last = id->bInterfaceNumber;
                        break;
                }
        }
 
        if (ps->desc == NULL) {
                /* first time or zero descriptors */
        } else if (new_iface) {
                /* new interface */
                ps->iface_index ++;
                ps->iface_index_alt = 0;
        } else {
                /* new alternate interface */
                ps->iface_index_alt ++;
        }
#if (USB_IFACE_MAX <= 0)
#error "USB_IFACE_MAX must be defined greater than zero"
#endif
        /* check for too many interfaces */
        if (ps->iface_index >= USB_IFACE_MAX) {
                DPRINTF("Interface limit reached\n");
                id = NULL;
        }
 
        /* store and return current descriptor */
        ps->desc = (struct usb_descriptor *)id;
        return (id);
}
 
/*------------------------------------------------------------------------*
 *      usb_edesc_foreach
 *
 * This function will iterate all the endpoint descriptors within an
 * interface descriptor. Starting value for the "ped" argument should
 * be a valid interface descriptor.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: A valid endpoint descriptor
 *------------------------------------------------------------------------*/
struct usb_endpoint_descriptor *
usb_edesc_foreach(struct usb_config_descriptor *cd,
    struct usb_endpoint_descriptor *ped)
{
        struct usb_descriptor *desc;
 
        desc = ((struct usb_descriptor *)ped);
 
        while ((desc = usb_desc_foreach(cd, desc))) {
                if (desc->bDescriptorType == UDESC_INTERFACE) {
                        break;
                }
                if (desc->bDescriptorType == UDESC_ENDPOINT) {
                        if (desc->bLength < sizeof(*ped)) {
                                /* endpoint descriptor is invalid */
                                break;
                        }
                        return ((struct usb_endpoint_descriptor *)desc);
                }
        }
        return (NULL);
}
 
/*------------------------------------------------------------------------*
 *      usb_ed_comp_foreach
 *
 * This function will iterate all the endpoint companion descriptors
 * within an endpoint descriptor in an interface descriptor. Starting
 * value for the "ped" argument should be a valid endpoint companion
 * descriptor.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: A valid endpoint companion descriptor
 *------------------------------------------------------------------------*/
struct usb_endpoint_ss_comp_descriptor *
usb_ed_comp_foreach(struct usb_config_descriptor *cd,
    struct usb_endpoint_ss_comp_descriptor *ped)
{
        struct usb_descriptor *desc;
 
        desc = ((struct usb_descriptor *)ped);
 
        while ((desc = usb_desc_foreach(cd, desc))) {
                if (desc->bDescriptorType == UDESC_INTERFACE)
                        break;
                if (desc->bDescriptorType == UDESC_ENDPOINT)
                        break;
                if (desc->bDescriptorType == UDESC_ENDPOINT_SS_COMP) {
                        if (desc->bLength < sizeof(*ped)) {
                                /* endpoint companion descriptor is invalid */
                                break;
                        }
                        return ((struct usb_endpoint_ss_comp_descriptor *)desc);
                }
        }
        return (NULL);
}
 
/*------------------------------------------------------------------------*
 *      usbd_get_no_descriptors
 *
 * This function will count the total number of descriptors in the
 * configuration descriptor of type "type".
 *------------------------------------------------------------------------*/
uint8_t
usbd_get_no_descriptors(struct usb_config_descriptor *cd, uint8_t type)
{
        struct usb_descriptor *desc = NULL;
        uint8_t count = 0;
 
        while ((desc = usb_desc_foreach(cd, desc))) {
                if (desc->bDescriptorType == type) {
                        count++;
                        if (count == 0xFF)
                                break;                  /* crazy */
                }
        }
        return (count);
}
 
/*------------------------------------------------------------------------*
 *      usbd_get_no_alts
 *
 * Return value:
 *   Number of alternate settings for the given interface descriptor
 *   pointer. If the USB descriptor is corrupt, the returned value can
 *   be greater than the actual number of alternate settings.
 *------------------------------------------------------------------------*/
uint8_t
usbd_get_no_alts(struct usb_config_descriptor *cd,
    struct usb_interface_descriptor *id)
{
        struct usb_descriptor *desc;
        uint8_t n;
        uint8_t ifaceno;
 
        /* Reset interface count */
 
        n = 0;
 
        /* Get the interface number */
 
        ifaceno = id->bInterfaceNumber;
 
        /* Iterate all the USB descriptors */
 
        desc = NULL;
        while ((desc = usb_desc_foreach(cd, desc))) {
                if ((desc->bDescriptorType == UDESC_INTERFACE) &&
                    (desc->bLength >= sizeof(*id))) {
                        id = (struct usb_interface_descriptor *)desc;
                        if (id->bInterfaceNumber == ifaceno) {
                                n++;
                                if (n == 0xFF)
                                        break;          /* crazy */
                        }
                }
        }
        return (n);
}