Loading...
1/*
2 * Wireless USB Host Controller
3 * Security support: encryption enablement, etc
4 *
5 * Copyright (C) 2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version
10 * 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 * 02110-1301, USA.
21 *
22 *
23 * FIXME: docs
24 */
25#include <linux/types.h>
26#include <linux/slab.h>
27#include <linux/usb/ch9.h>
28#include <linux/random.h>
29#include "wusbhc.h"
30
31static void wusbhc_set_gtk_callback(struct urb *urb);
32static void wusbhc_gtk_rekey_done_work(struct work_struct *work);
33
34int wusbhc_sec_create(struct wusbhc *wusbhc)
35{
36 wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data);
37 wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
38 wusbhc->gtk.descr.bReserved = 0;
39
40 wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK,
41 WUSB_KEY_INDEX_ORIGINATOR_HOST);
42
43 INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work);
44
45 return 0;
46}
47
48
49/* Called when the HC is destroyed */
50void wusbhc_sec_destroy(struct wusbhc *wusbhc)
51{
52}
53
54
55/**
56 * wusbhc_next_tkid - generate a new, currently unused, TKID
57 * @wusbhc: the WUSB host controller
58 * @wusb_dev: the device whose PTK the TKID is for
59 * (or NULL for a TKID for a GTK)
60 *
61 * The generated TKID consist of two parts: the device's authenicated
62 * address (or 0 or a GTK); and an incrementing number. This ensures
63 * that TKIDs cannot be shared between devices and by the time the
64 * incrementing number wraps around the older TKIDs will no longer be
65 * in use (a maximum of two keys may be active at any one time).
66 */
67static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
68{
69 u32 *tkid;
70 u32 addr;
71
72 if (wusb_dev == NULL) {
73 tkid = &wusbhc->gtk_tkid;
74 addr = 0;
75 } else {
76 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
77 addr = wusb_dev->addr & 0x7f;
78 }
79
80 *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
81
82 return *tkid;
83}
84
85static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
86{
87 const size_t key_size = sizeof(wusbhc->gtk.data);
88 u32 tkid;
89
90 tkid = wusbhc_next_tkid(wusbhc, NULL);
91
92 wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff;
93 wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff;
94 wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
95
96 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
97}
98
99/**
100 * wusbhc_sec_start - start the security management process
101 * @wusbhc: the WUSB host controller
102 *
103 * Generate and set an initial GTK on the host controller.
104 *
105 * Called when the HC is started.
106 */
107int wusbhc_sec_start(struct wusbhc *wusbhc)
108{
109 const size_t key_size = sizeof(wusbhc->gtk.data);
110 int result;
111
112 wusbhc_generate_gtk(wusbhc);
113
114 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
115 &wusbhc->gtk.descr.bKeyData, key_size);
116 if (result < 0)
117 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
118 result);
119
120 return result;
121}
122
123/**
124 * wusbhc_sec_stop - stop the security management process
125 * @wusbhc: the WUSB host controller
126 *
127 * Wait for any pending GTK rekeys to stop.
128 */
129void wusbhc_sec_stop(struct wusbhc *wusbhc)
130{
131 cancel_work_sync(&wusbhc->gtk_rekey_done_work);
132}
133
134
135/** @returns encryption type name */
136const char *wusb_et_name(u8 x)
137{
138 switch (x) {
139 case USB_ENC_TYPE_UNSECURE: return "unsecure";
140 case USB_ENC_TYPE_WIRED: return "wired";
141 case USB_ENC_TYPE_CCM_1: return "CCM-1";
142 case USB_ENC_TYPE_RSA_1: return "RSA-1";
143 default: return "unknown";
144 }
145}
146EXPORT_SYMBOL_GPL(wusb_et_name);
147
148/*
149 * Set the device encryption method
150 *
151 * We tell the device which encryption method to use; we do this when
152 * setting up the device's security.
153 */
154static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
155{
156 int result;
157 struct device *dev = &usb_dev->dev;
158 struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
159
160 if (value) {
161 value = wusb_dev->ccm1_etd.bEncryptionValue;
162 } else {
163 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
164 value = 0;
165 }
166 /* Set device's */
167 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
168 USB_REQ_SET_ENCRYPTION,
169 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
170 value, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
171 if (result < 0)
172 dev_err(dev, "Can't set device's WUSB encryption to "
173 "%s (value %d): %d\n",
174 wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
175 wusb_dev->ccm1_etd.bEncryptionValue, result);
176 return result;
177}
178
179/*
180 * Set the GTK to be used by a device.
181 *
182 * The device must be authenticated.
183 */
184static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
185{
186 struct usb_device *usb_dev = wusb_dev->usb_dev;
187
188 return usb_control_msg(
189 usb_dev, usb_sndctrlpipe(usb_dev, 0),
190 USB_REQ_SET_DESCRIPTOR,
191 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
192 USB_DT_KEY << 8 | wusbhc->gtk_index, 0,
193 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
194 1000);
195}
196
197
198/* FIXME: prototype for adding security */
199int wusb_dev_sec_add(struct wusbhc *wusbhc,
200 struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
201{
202 int result, bytes, secd_size;
203 struct device *dev = &usb_dev->dev;
204 struct usb_security_descriptor *secd;
205 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
206 const void *itr, *top;
207 char buf[64];
208
209 secd = kmalloc(sizeof(*secd), GFP_KERNEL);
210 if (secd == NULL) {
211 result = -ENOMEM;
212 goto out;
213 }
214
215 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
216 0, secd, sizeof(*secd));
217 if (result < sizeof(*secd)) {
218 dev_err(dev, "Can't read security descriptor or "
219 "not enough data: %d\n", result);
220 goto out;
221 }
222 secd_size = le16_to_cpu(secd->wTotalLength);
223 secd = krealloc(secd, secd_size, GFP_KERNEL);
224 if (secd == NULL) {
225 dev_err(dev, "Can't allocate space for security descriptors\n");
226 goto out;
227 }
228 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
229 0, secd, secd_size);
230 if (result < secd_size) {
231 dev_err(dev, "Can't read security descriptor or "
232 "not enough data: %d\n", result);
233 goto out;
234 }
235 bytes = 0;
236 itr = &secd[1];
237 top = (void *)secd + result;
238 while (itr < top) {
239 etd = itr;
240 if (top - itr < sizeof(*etd)) {
241 dev_err(dev, "BUG: bad device security descriptor; "
242 "not enough data (%zu vs %zu bytes left)\n",
243 top - itr, sizeof(*etd));
244 break;
245 }
246 if (etd->bLength < sizeof(*etd)) {
247 dev_err(dev, "BUG: bad device encryption descriptor; "
248 "descriptor is too short "
249 "(%u vs %zu needed)\n",
250 etd->bLength, sizeof(*etd));
251 break;
252 }
253 itr += etd->bLength;
254 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
255 "%s (0x%02x/%02x) ",
256 wusb_et_name(etd->bEncryptionType),
257 etd->bEncryptionValue, etd->bAuthKeyIndex);
258 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
259 ccm1_etd = etd;
260 }
261 /* This code only supports CCM1 as of now. */
262 /* FIXME: user has to choose which sec mode to use?
263 * In theory we want CCM */
264 if (ccm1_etd == NULL) {
265 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
266 "can't use!\n");
267 result = -EINVAL;
268 goto out;
269 }
270 wusb_dev->ccm1_etd = *ccm1_etd;
271 dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
272 buf, wusb_et_name(ccm1_etd->bEncryptionType),
273 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
274 result = 0;
275out:
276 kfree(secd);
277 return result;
278}
279
280void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
281{
282 /* Nothing so far */
283}
284
285/**
286 * Update the address of an unauthenticated WUSB device
287 *
288 * Once we have successfully authenticated, we take it to addr0 state
289 * and then to a normal address.
290 *
291 * Before the device's address (as known by it) was usb_dev->devnum |
292 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
293 */
294int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
295{
296 int result = -ENOMEM;
297 struct usb_device *usb_dev = wusb_dev->usb_dev;
298 struct device *dev = &usb_dev->dev;
299 u8 new_address = wusb_dev->addr & 0x7F;
300
301 /* Set address 0 */
302 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
303 USB_REQ_SET_ADDRESS, 0,
304 0, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
305 if (result < 0) {
306 dev_err(dev, "auth failed: can't set address 0: %d\n",
307 result);
308 goto error_addr0;
309 }
310 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
311 if (result < 0)
312 goto error_addr0;
313 usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
314 usb_ep0_reinit(usb_dev);
315
316 /* Set new (authenticated) address. */
317 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
318 USB_REQ_SET_ADDRESS, 0,
319 new_address, 0, NULL, 0,
320 1000 /* FIXME: arbitrary */);
321 if (result < 0) {
322 dev_err(dev, "auth failed: can't set address %u: %d\n",
323 new_address, result);
324 goto error_addr;
325 }
326 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
327 if (result < 0)
328 goto error_addr;
329 usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
330 usb_ep0_reinit(usb_dev);
331 usb_dev->authenticated = 1;
332error_addr:
333error_addr0:
334 return result;
335}
336
337/*
338 *
339 *
340 */
341/* FIXME: split and cleanup */
342int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
343 struct wusb_ckhdid *ck)
344{
345 int result = -ENOMEM;
346 struct usb_device *usb_dev = wusb_dev->usb_dev;
347 struct device *dev = &usb_dev->dev;
348 u32 tkid;
349 __le32 tkid_le;
350 struct usb_handshake *hs;
351 struct aes_ccm_nonce ccm_n;
352 u8 mic[8];
353 struct wusb_keydvt_in keydvt_in;
354 struct wusb_keydvt_out keydvt_out;
355
356 hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL);
357 if (hs == NULL) {
358 dev_err(dev, "can't allocate handshake data\n");
359 goto error_kzalloc;
360 }
361
362 /* We need to turn encryption before beginning the 4way
363 * hshake (WUSB1.0[.3.2.2]) */
364 result = wusb_dev_set_encryption(usb_dev, 1);
365 if (result < 0)
366 goto error_dev_set_encryption;
367
368 tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
369 tkid_le = cpu_to_le32(tkid);
370
371 hs[0].bMessageNumber = 1;
372 hs[0].bStatus = 0;
373 memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
374 hs[0].bReserved = 0;
375 memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
376 get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
377 memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */
378
379 result = usb_control_msg(
380 usb_dev, usb_sndctrlpipe(usb_dev, 0),
381 USB_REQ_SET_HANDSHAKE,
382 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
383 1, 0, &hs[0], sizeof(hs[0]), 1000 /* FIXME: arbitrary */);
384 if (result < 0) {
385 dev_err(dev, "Handshake1: request failed: %d\n", result);
386 goto error_hs1;
387 }
388
389 /* Handshake 2, from the device -- need to verify fields */
390 result = usb_control_msg(
391 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
392 USB_REQ_GET_HANDSHAKE,
393 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
394 2, 0, &hs[1], sizeof(hs[1]), 1000 /* FIXME: arbitrary */);
395 if (result < 0) {
396 dev_err(dev, "Handshake2: request failed: %d\n", result);
397 goto error_hs2;
398 }
399
400 result = -EINVAL;
401 if (hs[1].bMessageNumber != 2) {
402 dev_err(dev, "Handshake2 failed: bad message number %u\n",
403 hs[1].bMessageNumber);
404 goto error_hs2;
405 }
406 if (hs[1].bStatus != 0) {
407 dev_err(dev, "Handshake2 failed: bad status %u\n",
408 hs[1].bStatus);
409 goto error_hs2;
410 }
411 if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
412 dev_err(dev, "Handshake2 failed: TKID mismatch "
413 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
414 hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
415 hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
416 goto error_hs2;
417 }
418 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
419 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
420 goto error_hs2;
421 }
422
423 /* Setup the CCM nonce */
424 memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */
425 memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
426 ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
427 ccm_n.dest_addr.data[0] = wusb_dev->addr;
428 ccm_n.dest_addr.data[1] = 0;
429
430 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
431 memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
432 memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
433 result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
434 if (result < 0) {
435 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
436 result);
437 goto error_hs2;
438 }
439
440 /* Compute MIC and verify it */
441 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
442 if (result < 0) {
443 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
444 result);
445 goto error_hs2;
446 }
447
448 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
449 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
450 goto error_hs2;
451 }
452
453 /* Send Handshake3 */
454 hs[2].bMessageNumber = 3;
455 hs[2].bStatus = 0;
456 memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
457 hs[2].bReserved = 0;
458 memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
459 memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
460 result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
461 if (result < 0) {
462 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
463 result);
464 goto error_hs2;
465 }
466
467 result = usb_control_msg(
468 usb_dev, usb_sndctrlpipe(usb_dev, 0),
469 USB_REQ_SET_HANDSHAKE,
470 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
471 3, 0, &hs[2], sizeof(hs[2]), 1000 /* FIXME: arbitrary */);
472 if (result < 0) {
473 dev_err(dev, "Handshake3: request failed: %d\n", result);
474 goto error_hs3;
475 }
476
477 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
478 keydvt_out.ptk, sizeof(keydvt_out.ptk));
479 if (result < 0)
480 goto error_wusbhc_set_ptk;
481
482 result = wusb_dev_set_gtk(wusbhc, wusb_dev);
483 if (result < 0) {
484 dev_err(dev, "Set GTK for device: request failed: %d\n",
485 result);
486 goto error_wusbhc_set_gtk;
487 }
488
489 /* Update the device's address from unauth to auth */
490 if (usb_dev->authenticated == 0) {
491 result = wusb_dev_update_address(wusbhc, wusb_dev);
492 if (result < 0)
493 goto error_dev_update_address;
494 }
495 result = 0;
496 dev_info(dev, "device authenticated\n");
497
498error_dev_update_address:
499error_wusbhc_set_gtk:
500error_wusbhc_set_ptk:
501error_hs3:
502error_hs2:
503error_hs1:
504 memset(hs, 0, 3*sizeof(hs[0]));
505 memset(&keydvt_out, 0, sizeof(keydvt_out));
506 memset(&keydvt_in, 0, sizeof(keydvt_in));
507 memset(&ccm_n, 0, sizeof(ccm_n));
508 memset(mic, 0, sizeof(mic));
509 if (result < 0)
510 wusb_dev_set_encryption(usb_dev, 0);
511error_dev_set_encryption:
512 kfree(hs);
513error_kzalloc:
514 return result;
515}
516
517/*
518 * Once all connected and authenticated devices have received the new
519 * GTK, switch the host to using it.
520 */
521static void wusbhc_gtk_rekey_done_work(struct work_struct *work)
522{
523 struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work);
524 size_t key_size = sizeof(wusbhc->gtk.data);
525
526 mutex_lock(&wusbhc->mutex);
527
528 if (--wusbhc->pending_set_gtks == 0)
529 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
530
531 mutex_unlock(&wusbhc->mutex);
532}
533
534static void wusbhc_set_gtk_callback(struct urb *urb)
535{
536 struct wusbhc *wusbhc = urb->context;
537
538 queue_work(wusbd, &wusbhc->gtk_rekey_done_work);
539}
540
541/**
542 * wusbhc_gtk_rekey - generate and distribute a new GTK
543 * @wusbhc: the WUSB host controller
544 *
545 * Generate a new GTK and distribute it to all connected and
546 * authenticated devices. When all devices have the new GTK, the host
547 * starts using it.
548 *
549 * This must be called after every device disconnect (see [WUSB]
550 * section 6.2.11.2).
551 */
552void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
553{
554 static const size_t key_size = sizeof(wusbhc->gtk.data);
555 int p;
556
557 wusbhc_generate_gtk(wusbhc);
558
559 for (p = 0; p < wusbhc->ports_max; p++) {
560 struct wusb_dev *wusb_dev;
561
562 wusb_dev = wusbhc->port[p].wusb_dev;
563 if (!wusb_dev || !wusb_dev->usb_dev || !wusb_dev->usb_dev->authenticated)
564 continue;
565
566 usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev,
567 usb_sndctrlpipe(wusb_dev->usb_dev, 0),
568 (void *)wusb_dev->set_gtk_req,
569 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
570 wusbhc_set_gtk_callback, wusbhc);
571 if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0)
572 wusbhc->pending_set_gtks++;
573 }
574 if (wusbhc->pending_set_gtks == 0)
575 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
576}
1/*
2 * Wireless USB Host Controller
3 * Security support: encryption enablement, etc
4 *
5 * Copyright (C) 2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version
10 * 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 * 02110-1301, USA.
21 *
22 *
23 * FIXME: docs
24 */
25#include <linux/types.h>
26#include <linux/slab.h>
27#include <linux/usb/ch9.h>
28#include <linux/random.h>
29#include <linux/export.h>
30#include "wusbhc.h"
31
32static void wusbhc_gtk_rekey_work(struct work_struct *work);
33
34int wusbhc_sec_create(struct wusbhc *wusbhc)
35{
36 wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) +
37 sizeof(wusbhc->gtk.data);
38 wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
39 wusbhc->gtk.descr.bReserved = 0;
40 wusbhc->gtk_index = 0;
41
42 INIT_WORK(&wusbhc->gtk_rekey_work, wusbhc_gtk_rekey_work);
43
44 return 0;
45}
46
47
48/* Called when the HC is destroyed */
49void wusbhc_sec_destroy(struct wusbhc *wusbhc)
50{
51}
52
53
54/**
55 * wusbhc_next_tkid - generate a new, currently unused, TKID
56 * @wusbhc: the WUSB host controller
57 * @wusb_dev: the device whose PTK the TKID is for
58 * (or NULL for a TKID for a GTK)
59 *
60 * The generated TKID consists of two parts: the device's authenticated
61 * address (or 0 or a GTK); and an incrementing number. This ensures
62 * that TKIDs cannot be shared between devices and by the time the
63 * incrementing number wraps around the older TKIDs will no longer be
64 * in use (a maximum of two keys may be active at any one time).
65 */
66static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
67{
68 u32 *tkid;
69 u32 addr;
70
71 if (wusb_dev == NULL) {
72 tkid = &wusbhc->gtk_tkid;
73 addr = 0;
74 } else {
75 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
76 addr = wusb_dev->addr & 0x7f;
77 }
78
79 *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
80
81 return *tkid;
82}
83
84static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
85{
86 const size_t key_size = sizeof(wusbhc->gtk.data);
87 u32 tkid;
88
89 tkid = wusbhc_next_tkid(wusbhc, NULL);
90
91 wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff;
92 wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff;
93 wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
94
95 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
96}
97
98/**
99 * wusbhc_sec_start - start the security management process
100 * @wusbhc: the WUSB host controller
101 *
102 * Generate and set an initial GTK on the host controller.
103 *
104 * Called when the HC is started.
105 */
106int wusbhc_sec_start(struct wusbhc *wusbhc)
107{
108 const size_t key_size = sizeof(wusbhc->gtk.data);
109 int result;
110
111 wusbhc_generate_gtk(wusbhc);
112
113 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
114 &wusbhc->gtk.descr.bKeyData, key_size);
115 if (result < 0)
116 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
117 result);
118
119 return result;
120}
121
122/**
123 * wusbhc_sec_stop - stop the security management process
124 * @wusbhc: the WUSB host controller
125 *
126 * Wait for any pending GTK rekeys to stop.
127 */
128void wusbhc_sec_stop(struct wusbhc *wusbhc)
129{
130 cancel_work_sync(&wusbhc->gtk_rekey_work);
131}
132
133
134/** @returns encryption type name */
135const char *wusb_et_name(u8 x)
136{
137 switch (x) {
138 case USB_ENC_TYPE_UNSECURE: return "unsecure";
139 case USB_ENC_TYPE_WIRED: return "wired";
140 case USB_ENC_TYPE_CCM_1: return "CCM-1";
141 case USB_ENC_TYPE_RSA_1: return "RSA-1";
142 default: return "unknown";
143 }
144}
145EXPORT_SYMBOL_GPL(wusb_et_name);
146
147/*
148 * Set the device encryption method
149 *
150 * We tell the device which encryption method to use; we do this when
151 * setting up the device's security.
152 */
153static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
154{
155 int result;
156 struct device *dev = &usb_dev->dev;
157 struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
158
159 if (value) {
160 value = wusb_dev->ccm1_etd.bEncryptionValue;
161 } else {
162 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
163 value = 0;
164 }
165 /* Set device's */
166 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
167 USB_REQ_SET_ENCRYPTION,
168 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
169 value, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
170 if (result < 0)
171 dev_err(dev, "Can't set device's WUSB encryption to "
172 "%s (value %d): %d\n",
173 wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
174 wusb_dev->ccm1_etd.bEncryptionValue, result);
175 return result;
176}
177
178/*
179 * Set the GTK to be used by a device.
180 *
181 * The device must be authenticated.
182 */
183static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
184{
185 struct usb_device *usb_dev = wusb_dev->usb_dev;
186 u8 key_index = wusb_key_index(wusbhc->gtk_index,
187 WUSB_KEY_INDEX_TYPE_GTK, WUSB_KEY_INDEX_ORIGINATOR_HOST);
188
189 return usb_control_msg(
190 usb_dev, usb_sndctrlpipe(usb_dev, 0),
191 USB_REQ_SET_DESCRIPTOR,
192 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
193 USB_DT_KEY << 8 | key_index, 0,
194 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
195 USB_CTRL_SET_TIMEOUT);
196}
197
198
199/* FIXME: prototype for adding security */
200int wusb_dev_sec_add(struct wusbhc *wusbhc,
201 struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
202{
203 int result, bytes, secd_size;
204 struct device *dev = &usb_dev->dev;
205 struct usb_security_descriptor *secd, *new_secd;
206 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
207 const void *itr, *top;
208 char buf[64];
209
210 secd = kmalloc(sizeof(*secd), GFP_KERNEL);
211 if (secd == NULL) {
212 result = -ENOMEM;
213 goto out;
214 }
215
216 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
217 0, secd, sizeof(*secd));
218 if (result < sizeof(*secd)) {
219 dev_err(dev, "Can't read security descriptor or "
220 "not enough data: %d\n", result);
221 goto out;
222 }
223 secd_size = le16_to_cpu(secd->wTotalLength);
224 new_secd = krealloc(secd, secd_size, GFP_KERNEL);
225 if (new_secd == NULL) {
226 dev_err(dev,
227 "Can't allocate space for security descriptors\n");
228 goto out;
229 }
230 secd = new_secd;
231 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
232 0, secd, secd_size);
233 if (result < secd_size) {
234 dev_err(dev, "Can't read security descriptor or "
235 "not enough data: %d\n", result);
236 goto out;
237 }
238 bytes = 0;
239 itr = &secd[1];
240 top = (void *)secd + result;
241 while (itr < top) {
242 etd = itr;
243 if (top - itr < sizeof(*etd)) {
244 dev_err(dev, "BUG: bad device security descriptor; "
245 "not enough data (%zu vs %zu bytes left)\n",
246 top - itr, sizeof(*etd));
247 break;
248 }
249 if (etd->bLength < sizeof(*etd)) {
250 dev_err(dev, "BUG: bad device encryption descriptor; "
251 "descriptor is too short "
252 "(%u vs %zu needed)\n",
253 etd->bLength, sizeof(*etd));
254 break;
255 }
256 itr += etd->bLength;
257 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
258 "%s (0x%02x/%02x) ",
259 wusb_et_name(etd->bEncryptionType),
260 etd->bEncryptionValue, etd->bAuthKeyIndex);
261 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
262 ccm1_etd = etd;
263 }
264 /* This code only supports CCM1 as of now. */
265 /* FIXME: user has to choose which sec mode to use?
266 * In theory we want CCM */
267 if (ccm1_etd == NULL) {
268 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
269 "can't use!\n");
270 result = -EINVAL;
271 goto out;
272 }
273 wusb_dev->ccm1_etd = *ccm1_etd;
274 dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
275 buf, wusb_et_name(ccm1_etd->bEncryptionType),
276 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
277 result = 0;
278out:
279 kfree(secd);
280 return result;
281}
282
283void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
284{
285 /* Nothing so far */
286}
287
288/**
289 * Update the address of an unauthenticated WUSB device
290 *
291 * Once we have successfully authenticated, we take it to addr0 state
292 * and then to a normal address.
293 *
294 * Before the device's address (as known by it) was usb_dev->devnum |
295 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
296 */
297int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
298{
299 int result = -ENOMEM;
300 struct usb_device *usb_dev = wusb_dev->usb_dev;
301 struct device *dev = &usb_dev->dev;
302 u8 new_address = wusb_dev->addr & 0x7F;
303
304 /* Set address 0 */
305 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
306 USB_REQ_SET_ADDRESS,
307 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
308 0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
309 if (result < 0) {
310 dev_err(dev, "auth failed: can't set address 0: %d\n",
311 result);
312 goto error_addr0;
313 }
314 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
315 if (result < 0)
316 goto error_addr0;
317 usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
318 usb_ep0_reinit(usb_dev);
319
320 /* Set new (authenticated) address. */
321 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
322 USB_REQ_SET_ADDRESS,
323 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
324 new_address, 0, NULL, 0,
325 USB_CTRL_SET_TIMEOUT);
326 if (result < 0) {
327 dev_err(dev, "auth failed: can't set address %u: %d\n",
328 new_address, result);
329 goto error_addr;
330 }
331 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
332 if (result < 0)
333 goto error_addr;
334 usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
335 usb_ep0_reinit(usb_dev);
336 usb_dev->authenticated = 1;
337error_addr:
338error_addr0:
339 return result;
340}
341
342/*
343 *
344 *
345 */
346/* FIXME: split and cleanup */
347int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
348 struct wusb_ckhdid *ck)
349{
350 int result = -ENOMEM;
351 struct usb_device *usb_dev = wusb_dev->usb_dev;
352 struct device *dev = &usb_dev->dev;
353 u32 tkid;
354 __le32 tkid_le;
355 struct usb_handshake *hs;
356 struct aes_ccm_nonce ccm_n;
357 u8 mic[8];
358 struct wusb_keydvt_in keydvt_in;
359 struct wusb_keydvt_out keydvt_out;
360
361 hs = kcalloc(3, sizeof(hs[0]), GFP_KERNEL);
362 if (hs == NULL) {
363 dev_err(dev, "can't allocate handshake data\n");
364 goto error_kzalloc;
365 }
366
367 /* We need to turn encryption before beginning the 4way
368 * hshake (WUSB1.0[.3.2.2]) */
369 result = wusb_dev_set_encryption(usb_dev, 1);
370 if (result < 0)
371 goto error_dev_set_encryption;
372
373 tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
374 tkid_le = cpu_to_le32(tkid);
375
376 hs[0].bMessageNumber = 1;
377 hs[0].bStatus = 0;
378 memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
379 hs[0].bReserved = 0;
380 memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
381 get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
382 memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */
383
384 result = usb_control_msg(
385 usb_dev, usb_sndctrlpipe(usb_dev, 0),
386 USB_REQ_SET_HANDSHAKE,
387 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
388 1, 0, &hs[0], sizeof(hs[0]), USB_CTRL_SET_TIMEOUT);
389 if (result < 0) {
390 dev_err(dev, "Handshake1: request failed: %d\n", result);
391 goto error_hs1;
392 }
393
394 /* Handshake 2, from the device -- need to verify fields */
395 result = usb_control_msg(
396 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
397 USB_REQ_GET_HANDSHAKE,
398 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
399 2, 0, &hs[1], sizeof(hs[1]), USB_CTRL_GET_TIMEOUT);
400 if (result < 0) {
401 dev_err(dev, "Handshake2: request failed: %d\n", result);
402 goto error_hs2;
403 }
404
405 result = -EINVAL;
406 if (hs[1].bMessageNumber != 2) {
407 dev_err(dev, "Handshake2 failed: bad message number %u\n",
408 hs[1].bMessageNumber);
409 goto error_hs2;
410 }
411 if (hs[1].bStatus != 0) {
412 dev_err(dev, "Handshake2 failed: bad status %u\n",
413 hs[1].bStatus);
414 goto error_hs2;
415 }
416 if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
417 dev_err(dev, "Handshake2 failed: TKID mismatch "
418 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
419 hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
420 hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
421 goto error_hs2;
422 }
423 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
424 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
425 goto error_hs2;
426 }
427
428 /* Setup the CCM nonce */
429 memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */
430 memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
431 ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
432 ccm_n.dest_addr.data[0] = wusb_dev->addr;
433 ccm_n.dest_addr.data[1] = 0;
434
435 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
436 memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
437 memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
438 result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
439 if (result < 0) {
440 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
441 result);
442 goto error_hs2;
443 }
444
445 /* Compute MIC and verify it */
446 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
447 if (result < 0) {
448 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
449 result);
450 goto error_hs2;
451 }
452
453 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
454 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
455 goto error_hs2;
456 }
457
458 /* Send Handshake3 */
459 hs[2].bMessageNumber = 3;
460 hs[2].bStatus = 0;
461 memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
462 hs[2].bReserved = 0;
463 memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
464 memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
465 result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
466 if (result < 0) {
467 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
468 result);
469 goto error_hs2;
470 }
471
472 result = usb_control_msg(
473 usb_dev, usb_sndctrlpipe(usb_dev, 0),
474 USB_REQ_SET_HANDSHAKE,
475 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
476 3, 0, &hs[2], sizeof(hs[2]), USB_CTRL_SET_TIMEOUT);
477 if (result < 0) {
478 dev_err(dev, "Handshake3: request failed: %d\n", result);
479 goto error_hs3;
480 }
481
482 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
483 keydvt_out.ptk, sizeof(keydvt_out.ptk));
484 if (result < 0)
485 goto error_wusbhc_set_ptk;
486
487 result = wusb_dev_set_gtk(wusbhc, wusb_dev);
488 if (result < 0) {
489 dev_err(dev, "Set GTK for device: request failed: %d\n",
490 result);
491 goto error_wusbhc_set_gtk;
492 }
493
494 /* Update the device's address from unauth to auth */
495 if (usb_dev->authenticated == 0) {
496 result = wusb_dev_update_address(wusbhc, wusb_dev);
497 if (result < 0)
498 goto error_dev_update_address;
499 }
500 result = 0;
501 dev_info(dev, "device authenticated\n");
502
503error_dev_update_address:
504error_wusbhc_set_gtk:
505error_wusbhc_set_ptk:
506error_hs3:
507error_hs2:
508error_hs1:
509 memset(hs, 0, 3*sizeof(hs[0]));
510 memset(&keydvt_out, 0, sizeof(keydvt_out));
511 memset(&keydvt_in, 0, sizeof(keydvt_in));
512 memset(&ccm_n, 0, sizeof(ccm_n));
513 memset(mic, 0, sizeof(mic));
514 if (result < 0)
515 wusb_dev_set_encryption(usb_dev, 0);
516error_dev_set_encryption:
517 kfree(hs);
518error_kzalloc:
519 return result;
520}
521
522/*
523 * Once all connected and authenticated devices have received the new
524 * GTK, switch the host to using it.
525 */
526static void wusbhc_gtk_rekey_work(struct work_struct *work)
527{
528 struct wusbhc *wusbhc = container_of(work,
529 struct wusbhc, gtk_rekey_work);
530 size_t key_size = sizeof(wusbhc->gtk.data);
531 int port_idx;
532 struct wusb_dev *wusb_dev, *wusb_dev_next;
533 LIST_HEAD(rekey_list);
534
535 mutex_lock(&wusbhc->mutex);
536 /* generate the new key */
537 wusbhc_generate_gtk(wusbhc);
538 /* roll the gtk index. */
539 wusbhc->gtk_index = (wusbhc->gtk_index + 1) % (WUSB_KEY_INDEX_MAX + 1);
540 /*
541 * Save all connected devices on a list while holding wusbhc->mutex and
542 * take a reference to each one. Then submit the set key request to
543 * them after releasing the lock in order to avoid a deadlock.
544 */
545 for (port_idx = 0; port_idx < wusbhc->ports_max; port_idx++) {
546 wusb_dev = wusbhc->port[port_idx].wusb_dev;
547 if (!wusb_dev || !wusb_dev->usb_dev
548 || !wusb_dev->usb_dev->authenticated)
549 continue;
550
551 wusb_dev_get(wusb_dev);
552 list_add_tail(&wusb_dev->rekey_node, &rekey_list);
553 }
554 mutex_unlock(&wusbhc->mutex);
555
556 /* Submit the rekey requests without holding wusbhc->mutex. */
557 list_for_each_entry_safe(wusb_dev, wusb_dev_next, &rekey_list,
558 rekey_node) {
559 list_del_init(&wusb_dev->rekey_node);
560 dev_dbg(&wusb_dev->usb_dev->dev,
561 "%s: rekey device at port %d\n",
562 __func__, wusb_dev->port_idx);
563
564 if (wusb_dev_set_gtk(wusbhc, wusb_dev) < 0) {
565 dev_err(&wusb_dev->usb_dev->dev,
566 "%s: rekey device at port %d failed\n",
567 __func__, wusb_dev->port_idx);
568 }
569 wusb_dev_put(wusb_dev);
570 }
571
572 /* Switch the host controller to use the new GTK. */
573 mutex_lock(&wusbhc->mutex);
574 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
575 &wusbhc->gtk.descr.bKeyData, key_size);
576 mutex_unlock(&wusbhc->mutex);
577}
578
579/**
580 * wusbhc_gtk_rekey - generate and distribute a new GTK
581 * @wusbhc: the WUSB host controller
582 *
583 * Generate a new GTK and distribute it to all connected and
584 * authenticated devices. When all devices have the new GTK, the host
585 * starts using it.
586 *
587 * This must be called after every device disconnect (see [WUSB]
588 * section 6.2.11.2).
589 */
590void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
591{
592 /*
593 * We need to submit a URB to the downstream WUSB devices in order to
594 * change the group key. This can't be done while holding the
595 * wusbhc->mutex since that is also taken in the urb_enqueue routine
596 * and will cause a deadlock. Instead, queue a work item to do
597 * it when the lock is not held
598 */
599 queue_work(wusbd, &wusbhc->gtk_rekey_work);
600}