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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 /*
37 * WQ is singlethread because we need to serialize rekey operations.
38 * Use a separate workqueue for security operations instead of the
39 * wusbd workqueue because security operations may need to communicate
40 * directly with downstream wireless devices using synchronous URBs.
41 * If a device is not responding, this could block other host
42 * controller operations.
43 */
44 wusbhc->wq_security = create_singlethread_workqueue("wusbd_security");
45 if (wusbhc->wq_security == NULL) {
46 pr_err("WUSB-core: Cannot create wusbd_security workqueue\n");
47 return -ENOMEM;
48 }
49
50 wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) +
51 sizeof(wusbhc->gtk.data);
52 wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
53 wusbhc->gtk.descr.bReserved = 0;
54 wusbhc->gtk_index = 0;
55
56 INIT_WORK(&wusbhc->gtk_rekey_work, wusbhc_gtk_rekey_work);
57
58 return 0;
59}
60
61
62/* Called when the HC is destroyed */
63void wusbhc_sec_destroy(struct wusbhc *wusbhc)
64{
65 destroy_workqueue(wusbhc->wq_security);
66}
67
68
69/**
70 * wusbhc_next_tkid - generate a new, currently unused, TKID
71 * @wusbhc: the WUSB host controller
72 * @wusb_dev: the device whose PTK the TKID is for
73 * (or NULL for a TKID for a GTK)
74 *
75 * The generated TKID consists of two parts: the device's authenticated
76 * address (or 0 or a GTK); and an incrementing number. This ensures
77 * that TKIDs cannot be shared between devices and by the time the
78 * incrementing number wraps around the older TKIDs will no longer be
79 * in use (a maximum of two keys may be active at any one time).
80 */
81static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
82{
83 u32 *tkid;
84 u32 addr;
85
86 if (wusb_dev == NULL) {
87 tkid = &wusbhc->gtk_tkid;
88 addr = 0;
89 } else {
90 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
91 addr = wusb_dev->addr & 0x7f;
92 }
93
94 *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
95
96 return *tkid;
97}
98
99static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
100{
101 const size_t key_size = sizeof(wusbhc->gtk.data);
102 u32 tkid;
103
104 tkid = wusbhc_next_tkid(wusbhc, NULL);
105
106 wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff;
107 wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff;
108 wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
109
110 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
111}
112
113/**
114 * wusbhc_sec_start - start the security management process
115 * @wusbhc: the WUSB host controller
116 *
117 * Generate and set an initial GTK on the host controller.
118 *
119 * Called when the HC is started.
120 */
121int wusbhc_sec_start(struct wusbhc *wusbhc)
122{
123 const size_t key_size = sizeof(wusbhc->gtk.data);
124 int result;
125
126 wusbhc_generate_gtk(wusbhc);
127
128 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
129 &wusbhc->gtk.descr.bKeyData, key_size);
130 if (result < 0)
131 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
132 result);
133
134 return result;
135}
136
137/**
138 * wusbhc_sec_stop - stop the security management process
139 * @wusbhc: the WUSB host controller
140 *
141 * Wait for any pending GTK rekeys to stop.
142 */
143void wusbhc_sec_stop(struct wusbhc *wusbhc)
144{
145 cancel_work_sync(&wusbhc->gtk_rekey_work);
146}
147
148
149/** @returns encryption type name */
150const char *wusb_et_name(u8 x)
151{
152 switch (x) {
153 case USB_ENC_TYPE_UNSECURE: return "unsecure";
154 case USB_ENC_TYPE_WIRED: return "wired";
155 case USB_ENC_TYPE_CCM_1: return "CCM-1";
156 case USB_ENC_TYPE_RSA_1: return "RSA-1";
157 default: return "unknown";
158 }
159}
160EXPORT_SYMBOL_GPL(wusb_et_name);
161
162/*
163 * Set the device encryption method
164 *
165 * We tell the device which encryption method to use; we do this when
166 * setting up the device's security.
167 */
168static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
169{
170 int result;
171 struct device *dev = &usb_dev->dev;
172 struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
173
174 if (value) {
175 value = wusb_dev->ccm1_etd.bEncryptionValue;
176 } else {
177 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
178 value = 0;
179 }
180 /* Set device's */
181 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
182 USB_REQ_SET_ENCRYPTION,
183 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
184 value, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
185 if (result < 0)
186 dev_err(dev, "Can't set device's WUSB encryption to "
187 "%s (value %d): %d\n",
188 wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
189 wusb_dev->ccm1_etd.bEncryptionValue, result);
190 return result;
191}
192
193/*
194 * Set the GTK to be used by a device.
195 *
196 * The device must be authenticated.
197 */
198static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
199{
200 struct usb_device *usb_dev = wusb_dev->usb_dev;
201 u8 key_index = wusb_key_index(wusbhc->gtk_index,
202 WUSB_KEY_INDEX_TYPE_GTK, WUSB_KEY_INDEX_ORIGINATOR_HOST);
203
204 return usb_control_msg(
205 usb_dev, usb_sndctrlpipe(usb_dev, 0),
206 USB_REQ_SET_DESCRIPTOR,
207 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
208 USB_DT_KEY << 8 | key_index, 0,
209 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
210 USB_CTRL_SET_TIMEOUT);
211}
212
213
214/* FIXME: prototype for adding security */
215int wusb_dev_sec_add(struct wusbhc *wusbhc,
216 struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
217{
218 int result, bytes, secd_size;
219 struct device *dev = &usb_dev->dev;
220 struct usb_security_descriptor *secd, *new_secd;
221 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
222 const void *itr, *top;
223 char buf[64];
224
225 secd = kmalloc(sizeof(*secd), GFP_KERNEL);
226 if (secd == NULL) {
227 result = -ENOMEM;
228 goto out;
229 }
230
231 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
232 0, secd, sizeof(*secd));
233 if (result < sizeof(*secd)) {
234 dev_err(dev, "Can't read security descriptor or "
235 "not enough data: %d\n", result);
236 goto out;
237 }
238 secd_size = le16_to_cpu(secd->wTotalLength);
239 new_secd = krealloc(secd, secd_size, GFP_KERNEL);
240 if (new_secd == NULL) {
241 dev_err(dev,
242 "Can't allocate space for security descriptors\n");
243 goto out;
244 }
245 secd = new_secd;
246 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
247 0, secd, secd_size);
248 if (result < secd_size) {
249 dev_err(dev, "Can't read security descriptor or "
250 "not enough data: %d\n", result);
251 goto out;
252 }
253 bytes = 0;
254 itr = &secd[1];
255 top = (void *)secd + result;
256 while (itr < top) {
257 etd = itr;
258 if (top - itr < sizeof(*etd)) {
259 dev_err(dev, "BUG: bad device security descriptor; "
260 "not enough data (%zu vs %zu bytes left)\n",
261 top - itr, sizeof(*etd));
262 break;
263 }
264 if (etd->bLength < sizeof(*etd)) {
265 dev_err(dev, "BUG: bad device encryption descriptor; "
266 "descriptor is too short "
267 "(%u vs %zu needed)\n",
268 etd->bLength, sizeof(*etd));
269 break;
270 }
271 itr += etd->bLength;
272 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
273 "%s (0x%02x/%02x) ",
274 wusb_et_name(etd->bEncryptionType),
275 etd->bEncryptionValue, etd->bAuthKeyIndex);
276 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
277 ccm1_etd = etd;
278 }
279 /* This code only supports CCM1 as of now. */
280 /* FIXME: user has to choose which sec mode to use?
281 * In theory we want CCM */
282 if (ccm1_etd == NULL) {
283 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
284 "can't use!\n");
285 result = -EINVAL;
286 goto out;
287 }
288 wusb_dev->ccm1_etd = *ccm1_etd;
289 dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
290 buf, wusb_et_name(ccm1_etd->bEncryptionType),
291 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
292 result = 0;
293out:
294 kfree(secd);
295 return result;
296}
297
298void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
299{
300 /* Nothing so far */
301}
302
303/**
304 * Update the address of an unauthenticated WUSB device
305 *
306 * Once we have successfully authenticated, we take it to addr0 state
307 * and then to a normal address.
308 *
309 * Before the device's address (as known by it) was usb_dev->devnum |
310 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
311 */
312int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
313{
314 int result = -ENOMEM;
315 struct usb_device *usb_dev = wusb_dev->usb_dev;
316 struct device *dev = &usb_dev->dev;
317 u8 new_address = wusb_dev->addr & 0x7F;
318
319 /* Set address 0 */
320 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
321 USB_REQ_SET_ADDRESS,
322 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
323 0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
324 if (result < 0) {
325 dev_err(dev, "auth failed: can't set address 0: %d\n",
326 result);
327 goto error_addr0;
328 }
329 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
330 if (result < 0)
331 goto error_addr0;
332 usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
333 usb_ep0_reinit(usb_dev);
334
335 /* Set new (authenticated) address. */
336 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
337 USB_REQ_SET_ADDRESS,
338 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
339 new_address, 0, NULL, 0,
340 USB_CTRL_SET_TIMEOUT);
341 if (result < 0) {
342 dev_err(dev, "auth failed: can't set address %u: %d\n",
343 new_address, result);
344 goto error_addr;
345 }
346 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
347 if (result < 0)
348 goto error_addr;
349 usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
350 usb_ep0_reinit(usb_dev);
351 usb_dev->authenticated = 1;
352error_addr:
353error_addr0:
354 return result;
355}
356
357/*
358 *
359 *
360 */
361/* FIXME: split and cleanup */
362int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
363 struct wusb_ckhdid *ck)
364{
365 int result = -ENOMEM;
366 struct usb_device *usb_dev = wusb_dev->usb_dev;
367 struct device *dev = &usb_dev->dev;
368 u32 tkid;
369 __le32 tkid_le;
370 struct usb_handshake *hs;
371 struct aes_ccm_nonce ccm_n;
372 u8 mic[8];
373 struct wusb_keydvt_in keydvt_in;
374 struct wusb_keydvt_out keydvt_out;
375
376 hs = kcalloc(3, sizeof(hs[0]), GFP_KERNEL);
377 if (hs == NULL) {
378 dev_err(dev, "can't allocate handshake data\n");
379 goto error_kzalloc;
380 }
381
382 /* We need to turn encryption before beginning the 4way
383 * hshake (WUSB1.0[.3.2.2]) */
384 result = wusb_dev_set_encryption(usb_dev, 1);
385 if (result < 0)
386 goto error_dev_set_encryption;
387
388 tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
389 tkid_le = cpu_to_le32(tkid);
390
391 hs[0].bMessageNumber = 1;
392 hs[0].bStatus = 0;
393 memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
394 hs[0].bReserved = 0;
395 memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
396 get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
397 memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */
398
399 result = usb_control_msg(
400 usb_dev, usb_sndctrlpipe(usb_dev, 0),
401 USB_REQ_SET_HANDSHAKE,
402 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
403 1, 0, &hs[0], sizeof(hs[0]), USB_CTRL_SET_TIMEOUT);
404 if (result < 0) {
405 dev_err(dev, "Handshake1: request failed: %d\n", result);
406 goto error_hs1;
407 }
408
409 /* Handshake 2, from the device -- need to verify fields */
410 result = usb_control_msg(
411 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
412 USB_REQ_GET_HANDSHAKE,
413 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
414 2, 0, &hs[1], sizeof(hs[1]), USB_CTRL_GET_TIMEOUT);
415 if (result < 0) {
416 dev_err(dev, "Handshake2: request failed: %d\n", result);
417 goto error_hs2;
418 }
419
420 result = -EINVAL;
421 if (hs[1].bMessageNumber != 2) {
422 dev_err(dev, "Handshake2 failed: bad message number %u\n",
423 hs[1].bMessageNumber);
424 goto error_hs2;
425 }
426 if (hs[1].bStatus != 0) {
427 dev_err(dev, "Handshake2 failed: bad status %u\n",
428 hs[1].bStatus);
429 goto error_hs2;
430 }
431 if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
432 dev_err(dev, "Handshake2 failed: TKID mismatch "
433 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
434 hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
435 hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
436 goto error_hs2;
437 }
438 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
439 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
440 goto error_hs2;
441 }
442
443 /* Setup the CCM nonce */
444 memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */
445 memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
446 ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
447 ccm_n.dest_addr.data[0] = wusb_dev->addr;
448 ccm_n.dest_addr.data[1] = 0;
449
450 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
451 memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
452 memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
453 result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
454 if (result < 0) {
455 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
456 result);
457 goto error_hs2;
458 }
459
460 /* Compute MIC and verify it */
461 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
462 if (result < 0) {
463 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
464 result);
465 goto error_hs2;
466 }
467
468 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
469 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
470 goto error_hs2;
471 }
472
473 /* Send Handshake3 */
474 hs[2].bMessageNumber = 3;
475 hs[2].bStatus = 0;
476 memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
477 hs[2].bReserved = 0;
478 memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
479 memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
480 result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
481 if (result < 0) {
482 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
483 result);
484 goto error_hs2;
485 }
486
487 result = usb_control_msg(
488 usb_dev, usb_sndctrlpipe(usb_dev, 0),
489 USB_REQ_SET_HANDSHAKE,
490 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
491 3, 0, &hs[2], sizeof(hs[2]), USB_CTRL_SET_TIMEOUT);
492 if (result < 0) {
493 dev_err(dev, "Handshake3: request failed: %d\n", result);
494 goto error_hs3;
495 }
496
497 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
498 keydvt_out.ptk, sizeof(keydvt_out.ptk));
499 if (result < 0)
500 goto error_wusbhc_set_ptk;
501
502 result = wusb_dev_set_gtk(wusbhc, wusb_dev);
503 if (result < 0) {
504 dev_err(dev, "Set GTK for device: request failed: %d\n",
505 result);
506 goto error_wusbhc_set_gtk;
507 }
508
509 /* Update the device's address from unauth to auth */
510 if (usb_dev->authenticated == 0) {
511 result = wusb_dev_update_address(wusbhc, wusb_dev);
512 if (result < 0)
513 goto error_dev_update_address;
514 }
515 result = 0;
516 dev_info(dev, "device authenticated\n");
517
518error_dev_update_address:
519error_wusbhc_set_gtk:
520error_wusbhc_set_ptk:
521error_hs3:
522error_hs2:
523error_hs1:
524 memset(hs, 0, 3*sizeof(hs[0]));
525 memzero_explicit(&keydvt_out, sizeof(keydvt_out));
526 memzero_explicit(&keydvt_in, sizeof(keydvt_in));
527 memzero_explicit(&ccm_n, sizeof(ccm_n));
528 memzero_explicit(mic, sizeof(mic));
529 if (result < 0)
530 wusb_dev_set_encryption(usb_dev, 0);
531error_dev_set_encryption:
532 kfree(hs);
533error_kzalloc:
534 return result;
535}
536
537/*
538 * Once all connected and authenticated devices have received the new
539 * GTK, switch the host to using it.
540 */
541static void wusbhc_gtk_rekey_work(struct work_struct *work)
542{
543 struct wusbhc *wusbhc = container_of(work,
544 struct wusbhc, gtk_rekey_work);
545 size_t key_size = sizeof(wusbhc->gtk.data);
546 int port_idx;
547 struct wusb_dev *wusb_dev, *wusb_dev_next;
548 LIST_HEAD(rekey_list);
549
550 mutex_lock(&wusbhc->mutex);
551 /* generate the new key */
552 wusbhc_generate_gtk(wusbhc);
553 /* roll the gtk index. */
554 wusbhc->gtk_index = (wusbhc->gtk_index + 1) % (WUSB_KEY_INDEX_MAX + 1);
555 /*
556 * Save all connected devices on a list while holding wusbhc->mutex and
557 * take a reference to each one. Then submit the set key request to
558 * them after releasing the lock in order to avoid a deadlock.
559 */
560 for (port_idx = 0; port_idx < wusbhc->ports_max; port_idx++) {
561 wusb_dev = wusbhc->port[port_idx].wusb_dev;
562 if (!wusb_dev || !wusb_dev->usb_dev
563 || !wusb_dev->usb_dev->authenticated)
564 continue;
565
566 wusb_dev_get(wusb_dev);
567 list_add_tail(&wusb_dev->rekey_node, &rekey_list);
568 }
569 mutex_unlock(&wusbhc->mutex);
570
571 /* Submit the rekey requests without holding wusbhc->mutex. */
572 list_for_each_entry_safe(wusb_dev, wusb_dev_next, &rekey_list,
573 rekey_node) {
574 list_del_init(&wusb_dev->rekey_node);
575 dev_dbg(&wusb_dev->usb_dev->dev,
576 "%s: rekey device at port %d\n",
577 __func__, wusb_dev->port_idx);
578
579 if (wusb_dev_set_gtk(wusbhc, wusb_dev) < 0) {
580 dev_err(&wusb_dev->usb_dev->dev,
581 "%s: rekey device at port %d failed\n",
582 __func__, wusb_dev->port_idx);
583 }
584 wusb_dev_put(wusb_dev);
585 }
586
587 /* Switch the host controller to use the new GTK. */
588 mutex_lock(&wusbhc->mutex);
589 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
590 &wusbhc->gtk.descr.bKeyData, key_size);
591 mutex_unlock(&wusbhc->mutex);
592}
593
594/**
595 * wusbhc_gtk_rekey - generate and distribute a new GTK
596 * @wusbhc: the WUSB host controller
597 *
598 * Generate a new GTK and distribute it to all connected and
599 * authenticated devices. When all devices have the new GTK, the host
600 * starts using it.
601 *
602 * This must be called after every device disconnect (see [WUSB]
603 * section 6.2.11.2).
604 */
605void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
606{
607 /*
608 * We need to submit a URB to the downstream WUSB devices in order to
609 * change the group key. This can't be done while holding the
610 * wusbhc->mutex since that is also taken in the urb_enqueue routine
611 * and will cause a deadlock. Instead, queue a work item to do
612 * it when the lock is not held
613 */
614 queue_work(wusbhc->wq_security, &wusbhc->gtk_rekey_work);
615}