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>
30 static void wusbhc_set_gtk_callback(struct urb *urb);
31 static void wusbhc_gtk_rekey_done_work(struct work_struct *work);
33 int wusbhc_sec_create(struct wusbhc *wusbhc)
35 wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data);
36 wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
37 wusbhc->gtk.descr.bReserved = 0;
39 wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK,
40 WUSB_KEY_INDEX_ORIGINATOR_HOST);
42 INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work);
48 /* Called when the HC is destroyed */
49 void wusbhc_sec_destroy(struct wusbhc *wusbhc)
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)
60 * The generated TKID consist of two parts: the device's authenicated
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).
66 static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
71 if (wusb_dev == NULL) {
72 tkid = &wusbhc->gtk_tkid;
75 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
76 addr = wusb_dev->addr & 0x7f;
79 *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
84 static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
86 const size_t key_size = sizeof(wusbhc->gtk.data);
89 tkid = wusbhc_next_tkid(wusbhc, NULL);
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;
95 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
99 * wusbhc_sec_start - start the security management process
100 * @wusbhc: the WUSB host controller
102 * Generate and set an initial GTK on the host controller.
104 * Called when the HC is started.
106 int wusbhc_sec_start(struct wusbhc *wusbhc)
108 const size_t key_size = sizeof(wusbhc->gtk.data);
111 wusbhc_generate_gtk(wusbhc);
113 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
114 &wusbhc->gtk.descr.bKeyData, key_size);
116 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
123 * wusbhc_sec_stop - stop the security management process
124 * @wusbhc: the WUSB host controller
126 * Wait for any pending GTK rekeys to stop.
128 void wusbhc_sec_stop(struct wusbhc *wusbhc)
130 cancel_work_sync(&wusbhc->gtk_rekey_done_work);
134 /** @returns encryption type name */
135 const char *wusb_et_name(u8 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";
145 EXPORT_SYMBOL_GPL(wusb_et_name);
148 * Set the device encryption method
150 * We tell the device which encryption method to use; we do this when
151 * setting up the device's security.
153 static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
156 struct device *dev = &usb_dev->dev;
157 struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
160 value = wusb_dev->ccm1_etd.bEncryptionValue;
162 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
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, 1000 /* FIXME: arbitrary */);
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);
179 * Set the GTK to be used by a device.
181 * The device must be authenticated.
183 static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
185 struct usb_device *usb_dev = wusb_dev->usb_dev;
187 return usb_control_msg(
188 usb_dev, usb_sndctrlpipe(usb_dev, 0),
189 USB_REQ_SET_DESCRIPTOR,
190 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
191 USB_DT_KEY << 8 | wusbhc->gtk_index, 0,
192 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
197 /* FIXME: prototype for adding security */
198 int wusb_dev_sec_add(struct wusbhc *wusbhc,
199 struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
201 int result, bytes, secd_size;
202 struct device *dev = &usb_dev->dev;
203 struct usb_security_descriptor secd;
204 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
206 const void *itr, *top;
209 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
210 0, &secd, sizeof(secd));
211 if (result < sizeof(secd)) {
212 dev_err(dev, "Can't read security descriptor or "
213 "not enough data: %d\n", result);
216 secd_size = le16_to_cpu(secd.wTotalLength);
217 secd_buf = kmalloc(secd_size, GFP_KERNEL);
218 if (secd_buf == NULL) {
219 dev_err(dev, "Can't allocate space for security descriptors\n");
220 goto error_secd_alloc;
222 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
223 0, secd_buf, secd_size);
224 if (result < secd_size) {
225 dev_err(dev, "Can't read security descriptor or "
226 "not enough data: %d\n", result);
230 itr = secd_buf + sizeof(secd);
231 top = secd_buf + result;
234 if (top - itr < sizeof(*etd)) {
235 dev_err(dev, "BUG: bad device security descriptor; "
236 "not enough data (%zu vs %zu bytes left)\n",
237 top - itr, sizeof(*etd));
240 if (etd->bLength < sizeof(*etd)) {
241 dev_err(dev, "BUG: bad device encryption descriptor; "
242 "descriptor is too short "
243 "(%u vs %zu needed)\n",
244 etd->bLength, sizeof(*etd));
248 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
250 wusb_et_name(etd->bEncryptionType),
251 etd->bEncryptionValue, etd->bAuthKeyIndex);
252 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
255 /* This code only supports CCM1 as of now. */
256 /* FIXME: user has to choose which sec mode to use?
257 * In theory we want CCM */
258 if (ccm1_etd == NULL) {
259 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
264 wusb_dev->ccm1_etd = *ccm1_etd;
265 dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
266 buf, wusb_et_name(ccm1_etd->bEncryptionType),
267 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
282 void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
288 * Update the address of an unauthenticated WUSB device
290 * Once we have successfully authenticated, we take it to addr0 state
291 * and then to a normal address.
293 * Before the device's address (as known by it) was usb_dev->devnum |
294 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
296 int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
298 int result = -ENOMEM;
299 struct usb_device *usb_dev = wusb_dev->usb_dev;
300 struct device *dev = &usb_dev->dev;
301 u8 new_address = wusb_dev->addr & 0x7F;
304 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
305 USB_REQ_SET_ADDRESS, 0,
306 0, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
308 dev_err(dev, "auth failed: can't set address 0: %d\n",
312 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
315 usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
316 usb_ep0_reinit(usb_dev);
318 /* Set new (authenticated) address. */
319 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
320 USB_REQ_SET_ADDRESS, 0,
321 new_address, 0, NULL, 0,
322 1000 /* FIXME: arbitrary */);
324 dev_err(dev, "auth failed: can't set address %u: %d\n",
325 new_address, result);
328 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
331 usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
332 usb_ep0_reinit(usb_dev);
333 usb_dev->authenticated = 1;
343 /* FIXME: split and cleanup */
344 int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
345 struct wusb_ckhdid *ck)
347 int result = -ENOMEM;
348 struct usb_device *usb_dev = wusb_dev->usb_dev;
349 struct device *dev = &usb_dev->dev;
352 struct usb_handshake *hs;
353 struct aes_ccm_nonce ccm_n;
355 struct wusb_keydvt_in keydvt_in;
356 struct wusb_keydvt_out keydvt_out;
358 hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL);
360 dev_err(dev, "can't allocate handshake data\n");
364 /* We need to turn encryption before beginning the 4way
365 * hshake (WUSB1.0[.3.2.2]) */
366 result = wusb_dev_set_encryption(usb_dev, 1);
368 goto error_dev_set_encryption;
370 tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
371 tkid_le = cpu_to_le32(tkid);
373 hs[0].bMessageNumber = 1;
375 memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
377 memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
378 get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
379 memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */
381 result = usb_control_msg(
382 usb_dev, usb_sndctrlpipe(usb_dev, 0),
383 USB_REQ_SET_HANDSHAKE,
384 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
385 1, 0, &hs[0], sizeof(hs[0]), 1000 /* FIXME: arbitrary */);
387 dev_err(dev, "Handshake1: request failed: %d\n", result);
391 /* Handshake 2, from the device -- need to verify fields */
392 result = usb_control_msg(
393 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
394 USB_REQ_GET_HANDSHAKE,
395 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
396 2, 0, &hs[1], sizeof(hs[1]), 1000 /* FIXME: arbitrary */);
398 dev_err(dev, "Handshake2: request failed: %d\n", result);
403 if (hs[1].bMessageNumber != 2) {
404 dev_err(dev, "Handshake2 failed: bad message number %u\n",
405 hs[1].bMessageNumber);
408 if (hs[1].bStatus != 0) {
409 dev_err(dev, "Handshake2 failed: bad status %u\n",
413 if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
414 dev_err(dev, "Handshake2 failed: TKID mismatch "
415 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
416 hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
417 hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
420 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
421 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
425 /* Setup the CCM nonce */
426 memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */
427 memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
428 ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
429 ccm_n.dest_addr.data[0] = wusb_dev->addr;
430 ccm_n.dest_addr.data[1] = 0;
432 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
433 memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
434 memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
435 result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
437 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
442 /* Compute MIC and verify it */
443 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
445 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
450 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
451 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
455 /* Send Handshake3 */
456 hs[2].bMessageNumber = 3;
458 memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
460 memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
461 memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
462 result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
464 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
469 result = usb_control_msg(
470 usb_dev, usb_sndctrlpipe(usb_dev, 0),
471 USB_REQ_SET_HANDSHAKE,
472 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
473 3, 0, &hs[2], sizeof(hs[2]), 1000 /* FIXME: arbitrary */);
475 dev_err(dev, "Handshake3: request failed: %d\n", result);
479 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
480 keydvt_out.ptk, sizeof(keydvt_out.ptk));
482 goto error_wusbhc_set_ptk;
484 result = wusb_dev_set_gtk(wusbhc, wusb_dev);
486 dev_err(dev, "Set GTK for device: request failed: %d\n",
488 goto error_wusbhc_set_gtk;
491 /* Update the device's address from unauth to auth */
492 if (usb_dev->authenticated == 0) {
493 result = wusb_dev_update_address(wusbhc, wusb_dev);
495 goto error_dev_update_address;
498 dev_info(dev, "device authenticated\n");
500 error_dev_update_address:
501 error_wusbhc_set_gtk:
502 error_wusbhc_set_ptk:
506 memset(hs, 0, 3*sizeof(hs[0]));
507 memset(&keydvt_out, 0, sizeof(keydvt_out));
508 memset(&keydvt_in, 0, sizeof(keydvt_in));
509 memset(&ccm_n, 0, sizeof(ccm_n));
510 memset(mic, 0, sizeof(mic));
512 wusb_dev_set_encryption(usb_dev, 0);
513 error_dev_set_encryption:
520 * Once all connected and authenticated devices have received the new
521 * GTK, switch the host to using it.
523 static void wusbhc_gtk_rekey_done_work(struct work_struct *work)
525 struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work);
526 size_t key_size = sizeof(wusbhc->gtk.data);
528 mutex_lock(&wusbhc->mutex);
530 if (--wusbhc->pending_set_gtks == 0)
531 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
533 mutex_unlock(&wusbhc->mutex);
536 static void wusbhc_set_gtk_callback(struct urb *urb)
538 struct wusbhc *wusbhc = urb->context;
540 queue_work(wusbd, &wusbhc->gtk_rekey_done_work);
544 * wusbhc_gtk_rekey - generate and distribute a new GTK
545 * @wusbhc: the WUSB host controller
547 * Generate a new GTK and distribute it to all connected and
548 * authenticated devices. When all devices have the new GTK, the host
551 * This must be called after every device disconnect (see [WUSB]
554 void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
556 static const size_t key_size = sizeof(wusbhc->gtk.data);
559 wusbhc_generate_gtk(wusbhc);
561 for (p = 0; p < wusbhc->ports_max; p++) {
562 struct wusb_dev *wusb_dev;
564 wusb_dev = wusbhc->port[p].wusb_dev;
565 if (!wusb_dev || !wusb_dev->usb_dev | !wusb_dev->usb_dev->authenticated)
568 usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev,
569 usb_sndctrlpipe(wusb_dev->usb_dev, 0),
570 (void *)wusb_dev->set_gtk_req,
571 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
572 wusbhc_set_gtk_callback, wusbhc);
573 if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0)
574 wusbhc->pending_set_gtks++;
576 if (wusbhc->pending_set_gtks == 0)
577 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);