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