2 * Wireless USB Host Controller
3 * Security support: encryption enablement, etc
5 * Copyright (C) 2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
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.
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.
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
25 #include <linux/types.h>
26 #include <linux/usb/ch9.h>
27 #include <linux/random.h>
31 * DEBUG & SECURITY WARNING!!!!
33 * If you enable this past 1, the debug code will weaken the
34 * cryptographic safety of the system (on purpose, for debugging).
37 * we print secret keys and intermediate values all the way,
41 #include <linux/uwb/debug.h>
43 static void wusbhc_set_gtk_callback(struct urb *urb);
44 static void wusbhc_gtk_rekey_done_work(struct work_struct *work);
46 int wusbhc_sec_create(struct wusbhc *wusbhc)
48 wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data);
49 wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
50 wusbhc->gtk.descr.bReserved = 0;
52 wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK,
53 WUSB_KEY_INDEX_ORIGINATOR_HOST);
55 INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work);
61 /* Called when the HC is destroyed */
62 void wusbhc_sec_destroy(struct wusbhc *wusbhc)
68 * wusbhc_next_tkid - generate a new, currently unused, TKID
69 * @wusbhc: the WUSB host controller
70 * @wusb_dev: the device whose PTK the TKID is for
71 * (or NULL for a TKID for a GTK)
73 * The generated TKID consist of two parts: the device's authenicated
74 * address (or 0 or a GTK); and an incrementing number. This ensures
75 * that TKIDs cannot be shared between devices and by the time the
76 * incrementing number wraps around the older TKIDs will no longer be
77 * in use (a maximum of two keys may be active at any one time).
79 static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
84 if (wusb_dev == NULL) {
85 tkid = &wusbhc->gtk_tkid;
88 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
89 addr = wusb_dev->addr & 0x7f;
92 *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
97 static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
99 const size_t key_size = sizeof(wusbhc->gtk.data);
102 tkid = wusbhc_next_tkid(wusbhc, NULL);
104 wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff;
105 wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff;
106 wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
108 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
112 * wusbhc_sec_start - start the security management process
113 * @wusbhc: the WUSB host controller
115 * Generate and set an initial GTK on the host controller.
117 * Called when the HC is started.
119 int wusbhc_sec_start(struct wusbhc *wusbhc)
121 const size_t key_size = sizeof(wusbhc->gtk.data);
124 wusbhc_generate_gtk(wusbhc);
126 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
127 &wusbhc->gtk.descr.bKeyData, key_size);
129 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
136 * wusbhc_sec_stop - stop the security management process
137 * @wusbhc: the WUSB host controller
139 * Wait for any pending GTK rekeys to stop.
141 void wusbhc_sec_stop(struct wusbhc *wusbhc)
143 cancel_work_sync(&wusbhc->gtk_rekey_done_work);
147 /** @returns encryption type name */
148 const char *wusb_et_name(u8 x)
151 case USB_ENC_TYPE_UNSECURE: return "unsecure";
152 case USB_ENC_TYPE_WIRED: return "wired";
153 case USB_ENC_TYPE_CCM_1: return "CCM-1";
154 case USB_ENC_TYPE_RSA_1: return "RSA-1";
155 default: return "unknown";
158 EXPORT_SYMBOL_GPL(wusb_et_name);
161 * Set the device encryption method
163 * We tell the device which encryption method to use; we do this when
164 * setting up the device's security.
166 static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
169 struct device *dev = &usb_dev->dev;
170 struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
173 value = wusb_dev->ccm1_etd.bEncryptionValue;
175 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
179 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
180 USB_REQ_SET_ENCRYPTION,
181 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
182 value, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
184 dev_err(dev, "Can't set device's WUSB encryption to "
185 "%s (value %d): %d\n",
186 wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
187 wusb_dev->ccm1_etd.bEncryptionValue, result);
192 * Set the GTK to be used by a device.
194 * The device must be authenticated.
196 static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
198 struct usb_device *usb_dev = wusb_dev->usb_dev;
200 return usb_control_msg(
201 usb_dev, usb_sndctrlpipe(usb_dev, 0),
202 USB_REQ_SET_DESCRIPTOR,
203 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
204 USB_DT_KEY << 8 | wusbhc->gtk_index, 0,
205 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
210 /* FIXME: prototype for adding security */
211 int wusb_dev_sec_add(struct wusbhc *wusbhc,
212 struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
214 int result, bytes, secd_size;
215 struct device *dev = &usb_dev->dev;
216 struct usb_security_descriptor secd;
217 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
219 const void *itr, *top;
222 d_fnstart(3, dev, "(usb_dev %p, wusb_dev %p)\n", usb_dev, wusb_dev);
223 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
224 0, &secd, sizeof(secd));
225 if (result < sizeof(secd)) {
226 dev_err(dev, "Can't read security descriptor or "
227 "not enough data: %d\n", result);
230 secd_size = le16_to_cpu(secd.wTotalLength);
231 d_printf(5, dev, "got %d bytes of sec descriptor, total is %d\n",
233 secd_buf = kmalloc(secd_size, GFP_KERNEL);
234 if (secd_buf == NULL) {
235 dev_err(dev, "Can't allocate space for security descriptors\n");
236 goto error_secd_alloc;
238 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
239 0, secd_buf, secd_size);
240 if (result < secd_size) {
241 dev_err(dev, "Can't read security descriptor or "
242 "not enough data: %d\n", result);
245 d_printf(5, dev, "got %d bytes of sec descriptors\n", result);
247 itr = secd_buf + sizeof(secd);
248 top = secd_buf + result;
251 if (top - itr < sizeof(*etd)) {
252 dev_err(dev, "BUG: bad device security descriptor; "
253 "not enough data (%zu vs %zu bytes left)\n",
254 top - itr, sizeof(*etd));
257 if (etd->bLength < sizeof(*etd)) {
258 dev_err(dev, "BUG: bad device encryption descriptor; "
259 "descriptor is too short "
260 "(%u vs %zu needed)\n",
261 etd->bLength, sizeof(*etd));
265 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
267 wusb_et_name(etd->bEncryptionType),
268 etd->bEncryptionValue, etd->bAuthKeyIndex);
269 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
272 /* This code only supports CCM1 as of now. */
273 /* FIXME: user has to choose which sec mode to use?
274 * In theory we want CCM */
275 if (ccm1_etd == NULL) {
276 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
281 wusb_dev->ccm1_etd = *ccm1_etd;
282 dev_info(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
283 buf, wusb_et_name(ccm1_etd->bEncryptionType),
284 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
288 d_fnend(3, dev, "(usb_dev %p, wusb_dev %p) = %d\n",
289 usb_dev, wusb_dev, result);
301 void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
306 static void hs_printk(unsigned level, struct device *dev,
307 struct usb_handshake *hs)
310 " bMessageNumber: %u\n"
312 " tTKID: %02x %02x %02x\n"
313 " CDID: %02x %02x %02x %02x %02x %02x %02x %02x\n"
314 " %02x %02x %02x %02x %02x %02x %02x %02x\n"
315 " nonce: %02x %02x %02x %02x %02x %02x %02x %02x\n"
316 " %02x %02x %02x %02x %02x %02x %02x %02x\n"
317 " MIC: %02x %02x %02x %02x %02x %02x %02x %02x\n",
318 hs->bMessageNumber, hs->bStatus,
319 hs->tTKID[2], hs->tTKID[1], hs->tTKID[0],
320 hs->CDID[0], hs->CDID[1], hs->CDID[2], hs->CDID[3],
321 hs->CDID[4], hs->CDID[5], hs->CDID[6], hs->CDID[7],
322 hs->CDID[8], hs->CDID[9], hs->CDID[10], hs->CDID[11],
323 hs->CDID[12], hs->CDID[13], hs->CDID[14], hs->CDID[15],
324 hs->nonce[0], hs->nonce[1], hs->nonce[2], hs->nonce[3],
325 hs->nonce[4], hs->nonce[5], hs->nonce[6], hs->nonce[7],
326 hs->nonce[8], hs->nonce[9], hs->nonce[10], hs->nonce[11],
327 hs->nonce[12], hs->nonce[13], hs->nonce[14], hs->nonce[15],
328 hs->MIC[0], hs->MIC[1], hs->MIC[2], hs->MIC[3],
329 hs->MIC[4], hs->MIC[5], hs->MIC[6], hs->MIC[7]);
333 * Update the address of an unauthenticated WUSB device
335 * Once we have successfully authenticated, we take it to addr0 state
336 * and then to a normal address.
338 * Before the device's address (as known by it) was usb_dev->devnum |
339 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
341 static int wusb_dev_update_address(struct wusbhc *wusbhc,
342 struct wusb_dev *wusb_dev)
344 int result = -ENOMEM;
345 struct usb_device *usb_dev = wusb_dev->usb_dev;
346 struct device *dev = &usb_dev->dev;
347 u8 new_address = wusb_dev->addr & 0x7F;
350 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
351 USB_REQ_SET_ADDRESS, 0,
352 0, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
354 dev_err(dev, "auth failed: can't set address 0: %d\n",
358 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
361 usb_ep0_reinit(usb_dev);
363 /* Set new (authenticated) address. */
364 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
365 USB_REQ_SET_ADDRESS, 0,
366 new_address, 0, NULL, 0,
367 1000 /* FIXME: arbitrary */);
369 dev_err(dev, "auth failed: can't set address %u: %d\n",
370 new_address, result);
373 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
376 usb_ep0_reinit(usb_dev);
377 usb_dev->authenticated = 1;
387 /* FIXME: split and cleanup */
388 int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
389 struct wusb_ckhdid *ck)
391 int result = -ENOMEM;
392 struct usb_device *usb_dev = wusb_dev->usb_dev;
393 struct device *dev = &usb_dev->dev;
396 struct usb_handshake *hs;
397 struct aes_ccm_nonce ccm_n;
399 struct wusb_keydvt_in keydvt_in;
400 struct wusb_keydvt_out keydvt_out;
402 hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL);
404 dev_err(dev, "can't allocate handshake data\n");
408 /* We need to turn encryption before beginning the 4way
409 * hshake (WUSB1.0[.3.2.2]) */
410 result = wusb_dev_set_encryption(usb_dev, 1);
412 goto error_dev_set_encryption;
414 tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
415 tkid_le = cpu_to_le32(tkid);
417 hs[0].bMessageNumber = 1;
419 memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
421 memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
422 get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
423 memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */
425 d_printf(1, dev, "I: sending hs1:\n");
426 hs_printk(2, dev, &hs[0]);
428 result = usb_control_msg(
429 usb_dev, usb_sndctrlpipe(usb_dev, 0),
430 USB_REQ_SET_HANDSHAKE,
431 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
432 1, 0, &hs[0], sizeof(hs[0]), 1000 /* FIXME: arbitrary */);
434 dev_err(dev, "Handshake1: request failed: %d\n", result);
438 /* Handshake 2, from the device -- need to verify fields */
439 result = usb_control_msg(
440 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
441 USB_REQ_GET_HANDSHAKE,
442 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
443 2, 0, &hs[1], sizeof(hs[1]), 1000 /* FIXME: arbitrary */);
445 dev_err(dev, "Handshake2: request failed: %d\n", result);
448 d_printf(1, dev, "got HS2:\n");
449 hs_printk(2, dev, &hs[1]);
452 if (hs[1].bMessageNumber != 2) {
453 dev_err(dev, "Handshake2 failed: bad message number %u\n",
454 hs[1].bMessageNumber);
457 if (hs[1].bStatus != 0) {
458 dev_err(dev, "Handshake2 failed: bad status %u\n",
462 if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
463 dev_err(dev, "Handshake2 failed: TKID mismatch "
464 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
465 hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
466 hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
469 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
470 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
474 /* Setup the CCM nonce */
475 memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */
476 memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
477 ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
478 ccm_n.dest_addr.data[0] = wusb_dev->addr;
479 ccm_n.dest_addr.data[1] = 0;
481 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
482 memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
483 memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
484 result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
486 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
490 d_printf(2, dev, "KCK:\n");
491 d_dump(2, dev, keydvt_out.kck, sizeof(keydvt_out.kck));
492 d_printf(2, dev, "PTK:\n");
493 d_dump(2, dev, keydvt_out.ptk, sizeof(keydvt_out.ptk));
495 /* Compute MIC and verify it */
496 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
498 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
503 d_printf(2, dev, "MIC:\n");
504 d_dump(2, dev, mic, sizeof(mic));
505 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
506 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
510 /* Send Handshake3 */
511 hs[2].bMessageNumber = 3;
513 memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
515 memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
516 memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
517 result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
519 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
524 d_printf(1, dev, "I: sending hs3:\n");
525 hs_printk(2, dev, &hs[2]);
527 result = usb_control_msg(
528 usb_dev, usb_sndctrlpipe(usb_dev, 0),
529 USB_REQ_SET_HANDSHAKE,
530 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
531 3, 0, &hs[2], sizeof(hs[2]), 1000 /* FIXME: arbitrary */);
533 dev_err(dev, "Handshake3: request failed: %d\n", result);
537 d_printf(1, dev, "I: turning on encryption on host for device\n");
538 d_dump(2, dev, keydvt_out.ptk, sizeof(keydvt_out.ptk));
539 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
540 keydvt_out.ptk, sizeof(keydvt_out.ptk));
542 goto error_wusbhc_set_ptk;
544 d_printf(1, dev, "I: setting a GTK\n");
545 result = wusb_dev_set_gtk(wusbhc, wusb_dev);
547 dev_err(dev, "Set GTK for device: request failed: %d\n",
549 goto error_wusbhc_set_gtk;
552 /* Update the device's address from unauth to auth */
553 if (usb_dev->authenticated == 0) {
554 d_printf(1, dev, "I: updating addres to auth from non-auth\n");
555 result = wusb_dev_update_address(wusbhc, wusb_dev);
557 goto error_dev_update_address;
560 d_printf(1, dev, "I: 4way handshke done, device authenticated\n");
562 error_dev_update_address:
563 error_wusbhc_set_gtk:
564 error_wusbhc_set_ptk:
568 memset(hs, 0, 3*sizeof(hs[0]));
569 memset(&keydvt_out, 0, sizeof(keydvt_out));
570 memset(&keydvt_in, 0, sizeof(keydvt_in));
571 memset(&ccm_n, 0, sizeof(ccm_n));
572 memset(mic, 0, sizeof(mic));
575 wusb_dev_set_encryption(usb_dev, 0);
577 error_dev_set_encryption:
584 * Once all connected and authenticated devices have received the new
585 * GTK, switch the host to using it.
587 static void wusbhc_gtk_rekey_done_work(struct work_struct *work)
589 struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work);
590 size_t key_size = sizeof(wusbhc->gtk.data);
592 mutex_lock(&wusbhc->mutex);
594 if (--wusbhc->pending_set_gtks == 0)
595 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
597 mutex_unlock(&wusbhc->mutex);
600 static void wusbhc_set_gtk_callback(struct urb *urb)
602 struct wusbhc *wusbhc = urb->context;
604 queue_work(wusbd, &wusbhc->gtk_rekey_done_work);
608 * wusbhc_gtk_rekey - generate and distribute a new GTK
609 * @wusbhc: the WUSB host controller
611 * Generate a new GTK and distribute it to all connected and
612 * authenticated devices. When all devices have the new GTK, the host
615 * This must be called after every device disconnect (see [WUSB]
618 void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
620 static const size_t key_size = sizeof(wusbhc->gtk.data);
623 wusbhc_generate_gtk(wusbhc);
625 for (p = 0; p < wusbhc->ports_max; p++) {
626 struct wusb_dev *wusb_dev;
628 wusb_dev = wusbhc->port[p].wusb_dev;
629 if (!wusb_dev || !wusb_dev->usb_dev | !wusb_dev->usb_dev->authenticated)
632 usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev,
633 usb_sndctrlpipe(wusb_dev->usb_dev, 0),
634 (void *)wusb_dev->set_gtk_req,
635 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
636 wusbhc_set_gtk_callback, wusbhc);
637 if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0)
638 wusbhc->pending_set_gtks++;
640 if (wusbhc->pending_set_gtks == 0)
641 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);