1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2008-2020 Hans Petter Selasky. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include "implementation/global_implementation.h"
29
30 /*------------------------------------------------------------------------*
31 * usb_desc_foreach
32 *
33 * This function is the safe way to iterate across the USB config
34 * descriptor. It contains several checks against invalid
35 * descriptors. If the "desc" argument passed to this function is
36 * "NULL" the first descriptor, if any, will be returned.
37 *
38 * Return values:
39 * NULL: End of descriptors
40 * Else: Next descriptor after "desc"
41 *------------------------------------------------------------------------*/
42 struct usb_descriptor *
usb_desc_foreach(struct usb_config_descriptor * cd,struct usb_descriptor * _desc)43 usb_desc_foreach(struct usb_config_descriptor *cd,
44 struct usb_descriptor *_desc)
45 {
46 uint8_t *desc_next;
47 uint8_t *start;
48 uint8_t *end;
49 uint8_t *desc;
50
51 /* be NULL safe */
52 if (cd == NULL)
53 return (NULL);
54
55 /* We assume that the "wTotalLength" has been checked. */
56 start = (uint8_t *)cd;
57 end = start + UGETW(cd->wTotalLength);
58 desc = (uint8_t *)_desc;
59
60 /* Get start of next USB descriptor. */
61 if (desc == NULL)
62 desc = start;
63 else
64 desc = desc + desc[0];
65
66 /* Check that the next USB descriptor is within the range. */
67 if ((desc < start) || (desc >= end))
68 return (NULL); /* out of range, or EOD */
69
70 /* Check that the second next USB descriptor is within range. */
71 desc_next = desc + desc[0];
72 if ((desc_next < start) || (desc_next > end))
73 return (NULL); /* out of range */
74
75 /* Check minimum descriptor length. */
76 if (desc[0] < 3)
77 return (NULL); /* too short descriptor */
78
79 /* Return start of next descriptor. */
80 return ((struct usb_descriptor *)desc);
81 }
82
83 /*------------------------------------------------------------------------*
84 * usb_idesc_foreach
85 *
86 * This function will iterate the interface descriptors in the config
87 * descriptor. The parse state structure should be zeroed before
88 * calling this function the first time.
89 *
90 * Return values:
91 * NULL: End of descriptors
92 * Else: A valid interface descriptor
93 *------------------------------------------------------------------------*/
94 struct usb_interface_descriptor *
usb_idesc_foreach(struct usb_config_descriptor * cd,struct usb_idesc_parse_state * ps)95 usb_idesc_foreach(struct usb_config_descriptor *cd,
96 struct usb_idesc_parse_state *ps)
97 {
98 struct usb_interface_descriptor *id;
99 uint8_t new_iface;
100
101 /* retrieve current descriptor */
102 id = (struct usb_interface_descriptor *)ps->desc;
103 /* default is to start a new interface */
104 new_iface = 1;
105
106 while (1) {
107 id = (struct usb_interface_descriptor *)
108 usb_desc_foreach(cd, (struct usb_descriptor *)id);
109 if (id == NULL)
110 break;
111 if ((id->bDescriptorType == UDESC_INTERFACE) &&
112 (id->bLength >= sizeof(*id))) {
113 if (ps->iface_no_last == id->bInterfaceNumber) {
114 /*
115 * Don't allow more than 256 alternate
116 * settings to avoid overflowing the
117 * alternate index which is a 8-bit
118 * variable.
119 */
120 if (ps->iface_index_alt == 255) {
121 DPRINTF("Interface(%u) has more than 256 alternate settings\n",
122 id->bInterfaceNumber);
123 continue;
124 }
125 new_iface = 0;
126 }
127 ps->iface_no_last = id->bInterfaceNumber;
128 break;
129 }
130 }
131
132 if (ps->desc == NULL) {
133 /* first time or zero descriptors */
134 } else if (new_iface) {
135 /* new interface */
136 ps->iface_index ++;
137 ps->iface_index_alt = 0;
138 } else {
139 /* new alternate interface */
140 ps->iface_index_alt ++;
141 }
142 #if (USB_IFACE_MAX <= 0)
143 #error "USB_IFACE_MAX must be defined greater than zero"
144 #endif
145 /* check for too many interfaces */
146 if (ps->iface_index >= USB_IFACE_MAX) {
147 DPRINTF("Interface limit reached\n");
148 id = NULL;
149 }
150
151 /* store and return current descriptor */
152 ps->desc = (struct usb_descriptor *)id;
153 return (id);
154 }
155
156 /*------------------------------------------------------------------------*
157 * usb_edesc_foreach
158 *
159 * This function will iterate all the endpoint descriptors within an
160 * interface descriptor. Starting value for the "ped" argument should
161 * be a valid interface descriptor.
162 *
163 * Return values:
164 * NULL: End of descriptors
165 * Else: A valid endpoint descriptor
166 *------------------------------------------------------------------------*/
167 struct usb_endpoint_descriptor *
usb_edesc_foreach(struct usb_config_descriptor * cd,struct usb_endpoint_descriptor * ped)168 usb_edesc_foreach(struct usb_config_descriptor *cd,
169 struct usb_endpoint_descriptor *ped)
170 {
171 struct usb_descriptor *desc;
172
173 desc = ((struct usb_descriptor *)ped);
174
175 while ((desc = usb_desc_foreach(cd, desc))) {
176 if (desc->bDescriptorType == UDESC_INTERFACE) {
177 break;
178 }
179 if (desc->bDescriptorType == UDESC_ENDPOINT) {
180 if (desc->bLength < sizeof(*ped)) {
181 /* endpoint descriptor is invalid */
182 break;
183 }
184 return ((struct usb_endpoint_descriptor *)desc);
185 }
186 }
187 return (NULL);
188 }
189
190 /*------------------------------------------------------------------------*
191 * usb_ed_comp_foreach
192 *
193 * This function will iterate all the endpoint companion descriptors
194 * within an endpoint descriptor in an interface descriptor. Starting
195 * value for the "ped" argument should be a valid endpoint companion
196 * descriptor.
197 *
198 * Return values:
199 * NULL: End of descriptors
200 * Else: A valid endpoint companion descriptor
201 *------------------------------------------------------------------------*/
202 struct usb_endpoint_ss_comp_descriptor *
usb_ed_comp_foreach(struct usb_config_descriptor * cd,struct usb_endpoint_ss_comp_descriptor * ped)203 usb_ed_comp_foreach(struct usb_config_descriptor *cd,
204 struct usb_endpoint_ss_comp_descriptor *ped)
205 {
206 struct usb_descriptor *desc;
207
208 desc = ((struct usb_descriptor *)ped);
209
210 while ((desc = usb_desc_foreach(cd, desc))) {
211 if (desc->bDescriptorType == UDESC_INTERFACE)
212 break;
213 if (desc->bDescriptorType == UDESC_ENDPOINT)
214 break;
215 if (desc->bDescriptorType == UDESC_ENDPOINT_SS_COMP) {
216 if (desc->bLength < sizeof(*ped)) {
217 /* endpoint companion descriptor is invalid */
218 break;
219 }
220 return ((struct usb_endpoint_ss_comp_descriptor *)desc);
221 }
222 }
223 return (NULL);
224 }
225
226 /*------------------------------------------------------------------------*
227 * usbd_get_no_descriptors
228 *
229 * This function will count the total number of descriptors in the
230 * configuration descriptor of type "type".
231 *------------------------------------------------------------------------*/
232 uint8_t
usbd_get_no_descriptors(struct usb_config_descriptor * cd,uint8_t type)233 usbd_get_no_descriptors(struct usb_config_descriptor *cd, uint8_t type)
234 {
235 struct usb_descriptor *desc = NULL;
236 uint8_t count = 0;
237
238 while ((desc = usb_desc_foreach(cd, desc))) {
239 if (desc->bDescriptorType == type) {
240 count++;
241 if (count == 0xFF)
242 break; /* crazy */
243 }
244 }
245 return (count);
246 }
247
248 /*------------------------------------------------------------------------*
249 * usbd_get_no_alts
250 *
251 * Return value:
252 * Number of alternate settings for the given interface descriptor
253 * pointer. If the USB descriptor is corrupt, the returned value can
254 * be greater than the actual number of alternate settings.
255 *------------------------------------------------------------------------*/
256 uint8_t
usbd_get_no_alts(struct usb_config_descriptor * cd,struct usb_interface_descriptor * id)257 usbd_get_no_alts(struct usb_config_descriptor *cd,
258 struct usb_interface_descriptor *id)
259 {
260 struct usb_descriptor *desc;
261 uint8_t n;
262 uint8_t ifaceno;
263
264 /* Reset interface count */
265
266 n = 0;
267
268 /* Get the interface number */
269
270 ifaceno = id->bInterfaceNumber;
271
272 /* Iterate all the USB descriptors */
273
274 desc = NULL;
275 while ((desc = usb_desc_foreach(cd, desc))) {
276 if ((desc->bDescriptorType == UDESC_INTERFACE) &&
277 (desc->bLength >= sizeof(*id))) {
278 id = (struct usb_interface_descriptor *)desc;
279 if (id->bInterfaceNumber == ifaceno) {
280 n++;
281 if (n == 0xFF)
282 break; /* crazy */
283 }
284 }
285 }
286 return (n);
287 }
288