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/slab.h>
27 #include <linux/usb/ch9.h>
28 #include <linux/random.h>
29 #include <linux/export.h>
32 static void wusbhc_gtk_rekey_work(struct work_struct *work);
34 int wusbhc_sec_create(struct wusbhc *wusbhc)
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 wusbhc->gtk_index = 0;
41 INIT_WORK(&wusbhc->gtk_rekey_work, wusbhc_gtk_rekey_work);
47 /* Called when the HC is destroyed */
48 void wusbhc_sec_destroy(struct wusbhc *wusbhc)
54 * wusbhc_next_tkid - generate a new, currently unused, TKID
55 * @wusbhc: the WUSB host controller
56 * @wusb_dev: the device whose PTK the TKID is for
57 * (or NULL for a TKID for a GTK)
59 * The generated TKID consist of two parts: the device's authenicated
60 * address (or 0 or a GTK); and an incrementing number. This ensures
61 * that TKIDs cannot be shared between devices and by the time the
62 * incrementing number wraps around the older TKIDs will no longer be
63 * in use (a maximum of two keys may be active at any one time).
65 static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
70 if (wusb_dev == NULL) {
71 tkid = &wusbhc->gtk_tkid;
74 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
75 addr = wusb_dev->addr & 0x7f;
78 *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
83 static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
85 const size_t key_size = sizeof(wusbhc->gtk.data);
88 tkid = wusbhc_next_tkid(wusbhc, NULL);
90 wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff;
91 wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff;
92 wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
94 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
98 * wusbhc_sec_start - start the security management process
99 * @wusbhc: the WUSB host controller
101 * Generate and set an initial GTK on the host controller.
103 * Called when the HC is started.
105 int wusbhc_sec_start(struct wusbhc *wusbhc)
107 const size_t key_size = sizeof(wusbhc->gtk.data);
110 wusbhc_generate_gtk(wusbhc);
112 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
113 &wusbhc->gtk.descr.bKeyData, key_size);
115 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
122 * wusbhc_sec_stop - stop the security management process
123 * @wusbhc: the WUSB host controller
125 * Wait for any pending GTK rekeys to stop.
127 void wusbhc_sec_stop(struct wusbhc *wusbhc)
129 cancel_work_sync(&wusbhc->gtk_rekey_work);
133 /** @returns encryption type name */
134 const char *wusb_et_name(u8 x)
137 case USB_ENC_TYPE_UNSECURE: return "unsecure";
138 case USB_ENC_TYPE_WIRED: return "wired";
139 case USB_ENC_TYPE_CCM_1: return "CCM-1";
140 case USB_ENC_TYPE_RSA_1: return "RSA-1";
141 default: return "unknown";
144 EXPORT_SYMBOL_GPL(wusb_et_name);
147 * Set the device encryption method
149 * We tell the device which encryption method to use; we do this when
150 * setting up the device's security.
152 static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
155 struct device *dev = &usb_dev->dev;
156 struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
159 value = wusb_dev->ccm1_etd.bEncryptionValue;
161 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
165 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
166 USB_REQ_SET_ENCRYPTION,
167 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
168 value, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
170 dev_err(dev, "Can't set device's WUSB encryption to "
171 "%s (value %d): %d\n",
172 wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
173 wusb_dev->ccm1_etd.bEncryptionValue, result);
178 * Set the GTK to be used by a device.
180 * The device must be authenticated.
182 static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
184 struct usb_device *usb_dev = wusb_dev->usb_dev;
185 u8 key_index = wusb_key_index(wusbhc->gtk_index,
186 WUSB_KEY_INDEX_TYPE_GTK, WUSB_KEY_INDEX_ORIGINATOR_HOST);
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 | key_index, 0,
193 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
198 /* FIXME: prototype for adding security */
199 int wusb_dev_sec_add(struct wusbhc *wusbhc,
200 struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
202 int result, bytes, secd_size;
203 struct device *dev = &usb_dev->dev;
204 struct usb_security_descriptor *secd, *new_secd;
205 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
206 const void *itr, *top;
209 secd = kmalloc(sizeof(*secd), GFP_KERNEL);
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);
222 secd_size = le16_to_cpu(secd->wTotalLength);
223 new_secd = krealloc(secd, secd_size, GFP_KERNEL);
224 if (new_secd == NULL) {
225 dev_err(dev, "Can't allocate space for security descriptors\n");
229 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
231 if (result < secd_size) {
232 dev_err(dev, "Can't read security descriptor or "
233 "not enough data: %d\n", result);
238 top = (void *)secd + result;
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));
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));
255 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
257 wusb_et_name(etd->bEncryptionType),
258 etd->bEncryptionValue, etd->bAuthKeyIndex);
259 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
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, "
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);
281 void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
287 * Update the address of an unauthenticated WUSB device
289 * Once we have successfully authenticated, we take it to addr0 state
290 * and then to a normal address.
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.
295 int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
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;
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 */);
307 dev_err(dev, "auth failed: can't set address 0: %d\n",
311 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
314 usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
315 usb_ep0_reinit(usb_dev);
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 */);
323 dev_err(dev, "auth failed: can't set address %u: %d\n",
324 new_address, result);
327 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
330 usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
331 usb_ep0_reinit(usb_dev);
332 usb_dev->authenticated = 1;
342 /* FIXME: split and cleanup */
343 int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
344 struct wusb_ckhdid *ck)
346 int result = -ENOMEM;
347 struct usb_device *usb_dev = wusb_dev->usb_dev;
348 struct device *dev = &usb_dev->dev;
351 struct usb_handshake *hs;
352 struct aes_ccm_nonce ccm_n;
354 struct wusb_keydvt_in keydvt_in;
355 struct wusb_keydvt_out keydvt_out;
357 hs = kcalloc(3, sizeof(hs[0]), GFP_KERNEL);
359 dev_err(dev, "can't allocate handshake data\n");
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);
367 goto error_dev_set_encryption;
369 tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
370 tkid_le = cpu_to_le32(tkid);
372 hs[0].bMessageNumber = 1;
374 memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
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] */
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 */);
386 dev_err(dev, "Handshake1: request failed: %d\n", result);
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 */);
397 dev_err(dev, "Handshake2: request failed: %d\n", result);
402 if (hs[1].bMessageNumber != 2) {
403 dev_err(dev, "Handshake2 failed: bad message number %u\n",
404 hs[1].bMessageNumber);
407 if (hs[1].bStatus != 0) {
408 dev_err(dev, "Handshake2 failed: bad status %u\n",
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]);
419 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
420 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
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;
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);
436 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
441 /* Compute MIC and verify it */
442 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
444 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
449 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
450 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
454 /* Send Handshake3 */
455 hs[2].bMessageNumber = 3;
457 memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
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]);
463 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
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 */);
474 dev_err(dev, "Handshake3: request failed: %d\n", result);
478 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
479 keydvt_out.ptk, sizeof(keydvt_out.ptk));
481 goto error_wusbhc_set_ptk;
483 result = wusb_dev_set_gtk(wusbhc, wusb_dev);
485 dev_err(dev, "Set GTK for device: request failed: %d\n",
487 goto error_wusbhc_set_gtk;
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);
494 goto error_dev_update_address;
497 dev_info(dev, "device authenticated\n");
499 error_dev_update_address:
500 error_wusbhc_set_gtk:
501 error_wusbhc_set_ptk:
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));
511 wusb_dev_set_encryption(usb_dev, 0);
512 error_dev_set_encryption:
519 * Once all connected and authenticated devices have received the new
520 * GTK, switch the host to using it.
522 static void wusbhc_gtk_rekey_work(struct work_struct *work)
524 struct wusbhc *wusbhc = container_of(work,
525 struct wusbhc, gtk_rekey_work);
526 size_t key_size = sizeof(wusbhc->gtk.data);
528 struct wusb_dev *wusb_dev, *wusb_dev_next;
529 LIST_HEAD(rekey_list);
531 mutex_lock(&wusbhc->mutex);
532 /* generate the new key */
533 wusbhc_generate_gtk(wusbhc);
534 /* roll the gtk index. */
535 wusbhc->gtk_index = (wusbhc->gtk_index + 1) % (WUSB_KEY_INDEX_MAX + 1);
537 * Save all connected devices on a list while holding wusbhc->mutex and
538 * take a reference to each one. Then submit the set key request to
539 * them after releasing the lock in order to avoid a deadlock.
541 for (port_idx = 0; port_idx < wusbhc->ports_max; port_idx++) {
542 wusb_dev = wusbhc->port[port_idx].wusb_dev;
543 if (!wusb_dev || !wusb_dev->usb_dev
544 || !wusb_dev->usb_dev->authenticated)
547 wusb_dev_get(wusb_dev);
548 list_add_tail(&wusb_dev->rekey_node, &rekey_list);
550 mutex_unlock(&wusbhc->mutex);
552 /* Submit the rekey requests without holding wusbhc->mutex. */
553 list_for_each_entry_safe(wusb_dev, wusb_dev_next, &rekey_list,
555 list_del_init(&wusb_dev->rekey_node);
556 dev_dbg(&wusb_dev->usb_dev->dev, "%s: rekey device at port %d\n",
557 __func__, wusb_dev->port_idx);
559 if (wusb_dev_set_gtk(wusbhc, wusb_dev) < 0) {
560 dev_err(&wusb_dev->usb_dev->dev, "%s: rekey device at port %d failed\n",
561 __func__, wusb_dev->port_idx);
563 wusb_dev_put(wusb_dev);
566 /* Switch the host controller to use the new GTK. */
567 mutex_lock(&wusbhc->mutex);
568 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
569 &wusbhc->gtk.descr.bKeyData, key_size);
570 mutex_unlock(&wusbhc->mutex);
574 * wusbhc_gtk_rekey - generate and distribute a new GTK
575 * @wusbhc: the WUSB host controller
577 * Generate a new GTK and distribute it to all connected and
578 * authenticated devices. When all devices have the new GTK, the host
581 * This must be called after every device disconnect (see [WUSB]
584 void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
587 * We need to submit a URB to the downstream WUSB devices in order to
588 * change the group key. This can't be done while holding the
589 * wusbhc->mutex since that is also taken in the urb_enqueue routine
590 * and will cause a deadlock. Instead, queue a work item to do
591 * it when the lock is not held
593 queue_work(wusbd, &wusbhc->gtk_rekey_work);