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
)
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.
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");
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;
56 INIT_WORK(&wusbhc
->gtk_rekey_work
, wusbhc_gtk_rekey_work
);
62 /* Called when the HC is destroyed */
63 void wusbhc_sec_destroy(struct wusbhc
*wusbhc
)
65 destroy_workqueue(wusbhc
->wq_security
);
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)
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).
81 static u32
wusbhc_next_tkid(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
)
86 if (wusb_dev
== NULL
) {
87 tkid
= &wusbhc
->gtk_tkid
;
90 tkid
= &wusb_port_by_idx(wusbhc
, wusb_dev
->port_idx
)->ptk_tkid
;
91 addr
= wusb_dev
->addr
& 0x7f;
94 *tkid
= (addr
<< 8) | ((*tkid
+ 1) & 0xff);
99 static void wusbhc_generate_gtk(struct wusbhc
*wusbhc
)
101 const size_t key_size
= sizeof(wusbhc
->gtk
.data
);
104 tkid
= wusbhc_next_tkid(wusbhc
, NULL
);
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;
110 get_random_bytes(wusbhc
->gtk
.descr
.bKeyData
, key_size
);
114 * wusbhc_sec_start - start the security management process
115 * @wusbhc: the WUSB host controller
117 * Generate and set an initial GTK on the host controller.
119 * Called when the HC is started.
121 int wusbhc_sec_start(struct wusbhc
*wusbhc
)
123 const size_t key_size
= sizeof(wusbhc
->gtk
.data
);
126 wusbhc_generate_gtk(wusbhc
);
128 result
= wusbhc
->set_gtk(wusbhc
, wusbhc
->gtk_tkid
,
129 &wusbhc
->gtk
.descr
.bKeyData
, key_size
);
131 dev_err(wusbhc
->dev
, "cannot set GTK for the host: %d\n",
138 * wusbhc_sec_stop - stop the security management process
139 * @wusbhc: the WUSB host controller
141 * Wait for any pending GTK rekeys to stop.
143 void wusbhc_sec_stop(struct wusbhc
*wusbhc
)
145 cancel_work_sync(&wusbhc
->gtk_rekey_work
);
149 /** @returns encryption type name */
150 const char *wusb_et_name(u8 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";
160 EXPORT_SYMBOL_GPL(wusb_et_name
);
163 * Set the device encryption method
165 * We tell the device which encryption method to use; we do this when
166 * setting up the device's security.
168 static int wusb_dev_set_encryption(struct usb_device
*usb_dev
, int value
)
171 struct device
*dev
= &usb_dev
->dev
;
172 struct wusb_dev
*wusb_dev
= usb_dev
->wusb_dev
;
175 value
= wusb_dev
->ccm1_etd
.bEncryptionValue
;
177 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
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
);
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
);
194 * Set the GTK to be used by a device.
196 * The device must be authenticated.
198 static int wusb_dev_set_gtk(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
)
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
);
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
);
214 /* FIXME: prototype for adding security */
215 int wusb_dev_sec_add(struct wusbhc
*wusbhc
,
216 struct usb_device
*usb_dev
, struct wusb_dev
*wusb_dev
)
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
;
225 secd
= kmalloc(sizeof(*secd
), GFP_KERNEL
);
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
);
238 secd_size
= le16_to_cpu(secd
->wTotalLength
);
239 new_secd
= krealloc(secd
, secd_size
, GFP_KERNEL
);
240 if (new_secd
== NULL
) {
242 "Can't allocate space for security descriptors\n");
247 result
= usb_get_descriptor(usb_dev
, USB_DT_SECURITY
,
249 if (result
< secd_size
) {
250 dev_err(dev
, "Can't read security descriptor or "
251 "not enough data: %d\n", result
);
256 top
= (void *)secd
+ result
;
259 if (top
- itr
< sizeof(*etd
)) {
260 dev_err(dev
, "BUG: bad device security descriptor; "
261 "not enough data (%zu vs %zu bytes left)\n",
262 top
- itr
, sizeof(*etd
));
265 if (etd
->bLength
< sizeof(*etd
)) {
266 dev_err(dev
, "BUG: bad device encryption descriptor; "
267 "descriptor is too short "
268 "(%u vs %zu needed)\n",
269 etd
->bLength
, sizeof(*etd
));
273 bytes
+= snprintf(buf
+ bytes
, sizeof(buf
) - bytes
,
275 wusb_et_name(etd
->bEncryptionType
),
276 etd
->bEncryptionValue
, etd
->bAuthKeyIndex
);
277 if (etd
->bEncryptionType
== USB_ENC_TYPE_CCM_1
)
280 /* This code only supports CCM1 as of now. */
281 /* FIXME: user has to choose which sec mode to use?
282 * In theory we want CCM */
283 if (ccm1_etd
== NULL
) {
284 dev_err(dev
, "WUSB device doesn't support CCM1 encryption, "
289 wusb_dev
->ccm1_etd
= *ccm1_etd
;
290 dev_dbg(dev
, "supported encryption: %s; using %s (0x%02x/%02x)\n",
291 buf
, wusb_et_name(ccm1_etd
->bEncryptionType
),
292 ccm1_etd
->bEncryptionValue
, ccm1_etd
->bAuthKeyIndex
);
299 void wusb_dev_sec_rm(struct wusb_dev
*wusb_dev
)
305 * Update the address of an unauthenticated WUSB device
307 * Once we have successfully authenticated, we take it to addr0 state
308 * and then to a normal address.
310 * Before the device's address (as known by it) was usb_dev->devnum |
311 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
313 int wusb_dev_update_address(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
)
315 int result
= -ENOMEM
;
316 struct usb_device
*usb_dev
= wusb_dev
->usb_dev
;
317 struct device
*dev
= &usb_dev
->dev
;
318 u8 new_address
= wusb_dev
->addr
& 0x7F;
321 result
= usb_control_msg(usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
323 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
324 0, 0, NULL
, 0, USB_CTRL_SET_TIMEOUT
);
326 dev_err(dev
, "auth failed: can't set address 0: %d\n",
330 result
= wusb_set_dev_addr(wusbhc
, wusb_dev
, 0);
333 usb_set_device_state(usb_dev
, USB_STATE_DEFAULT
);
334 usb_ep0_reinit(usb_dev
);
336 /* Set new (authenticated) address. */
337 result
= usb_control_msg(usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
339 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
340 new_address
, 0, NULL
, 0,
341 USB_CTRL_SET_TIMEOUT
);
343 dev_err(dev
, "auth failed: can't set address %u: %d\n",
344 new_address
, result
);
347 result
= wusb_set_dev_addr(wusbhc
, wusb_dev
, new_address
);
350 usb_set_device_state(usb_dev
, USB_STATE_ADDRESS
);
351 usb_ep0_reinit(usb_dev
);
352 usb_dev
->authenticated
= 1;
362 /* FIXME: split and cleanup */
363 int wusb_dev_4way_handshake(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
,
364 struct wusb_ckhdid
*ck
)
366 int result
= -ENOMEM
;
367 struct usb_device
*usb_dev
= wusb_dev
->usb_dev
;
368 struct device
*dev
= &usb_dev
->dev
;
371 struct usb_handshake
*hs
;
372 struct aes_ccm_nonce ccm_n
;
374 struct wusb_keydvt_in keydvt_in
;
375 struct wusb_keydvt_out keydvt_out
;
377 hs
= kcalloc(3, sizeof(hs
[0]), GFP_KERNEL
);
381 /* We need to turn encryption before beginning the 4way
382 * hshake (WUSB1.0[.3.2.2]) */
383 result
= wusb_dev_set_encryption(usb_dev
, 1);
385 goto error_dev_set_encryption
;
387 tkid
= wusbhc_next_tkid(wusbhc
, wusb_dev
);
388 tkid_le
= cpu_to_le32(tkid
);
390 hs
[0].bMessageNumber
= 1;
392 memcpy(hs
[0].tTKID
, &tkid_le
, sizeof(hs
[0].tTKID
));
394 memcpy(hs
[0].CDID
, &wusb_dev
->cdid
, sizeof(hs
[0].CDID
));
395 get_random_bytes(&hs
[0].nonce
, sizeof(hs
[0].nonce
));
396 memset(hs
[0].MIC
, 0, sizeof(hs
[0].MIC
)); /* Per WUSB1.0[T7-22] */
398 result
= usb_control_msg(
399 usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
400 USB_REQ_SET_HANDSHAKE
,
401 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
402 1, 0, &hs
[0], sizeof(hs
[0]), USB_CTRL_SET_TIMEOUT
);
404 dev_err(dev
, "Handshake1: request failed: %d\n", result
);
408 /* Handshake 2, from the device -- need to verify fields */
409 result
= usb_control_msg(
410 usb_dev
, usb_rcvctrlpipe(usb_dev
, 0),
411 USB_REQ_GET_HANDSHAKE
,
412 USB_DIR_IN
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
413 2, 0, &hs
[1], sizeof(hs
[1]), USB_CTRL_GET_TIMEOUT
);
415 dev_err(dev
, "Handshake2: request failed: %d\n", result
);
420 if (hs
[1].bMessageNumber
!= 2) {
421 dev_err(dev
, "Handshake2 failed: bad message number %u\n",
422 hs
[1].bMessageNumber
);
425 if (hs
[1].bStatus
!= 0) {
426 dev_err(dev
, "Handshake2 failed: bad status %u\n",
430 if (memcmp(hs
[0].tTKID
, hs
[1].tTKID
, sizeof(hs
[0].tTKID
))) {
431 dev_err(dev
, "Handshake2 failed: TKID mismatch "
432 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
433 hs
[0].tTKID
[0], hs
[0].tTKID
[1], hs
[0].tTKID
[2],
434 hs
[1].tTKID
[0], hs
[1].tTKID
[1], hs
[1].tTKID
[2]);
437 if (memcmp(hs
[0].CDID
, hs
[1].CDID
, sizeof(hs
[0].CDID
))) {
438 dev_err(dev
, "Handshake2 failed: CDID mismatch\n");
442 /* Setup the CCM nonce */
443 memset(&ccm_n
.sfn
, 0, sizeof(ccm_n
.sfn
)); /* Per WUSB1.0[6.5.2] */
444 memcpy(ccm_n
.tkid
, &tkid_le
, sizeof(ccm_n
.tkid
));
445 ccm_n
.src_addr
= wusbhc
->uwb_rc
->uwb_dev
.dev_addr
;
446 ccm_n
.dest_addr
.data
[0] = wusb_dev
->addr
;
447 ccm_n
.dest_addr
.data
[1] = 0;
449 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
450 memcpy(keydvt_in
.hnonce
, hs
[0].nonce
, sizeof(keydvt_in
.hnonce
));
451 memcpy(keydvt_in
.dnonce
, hs
[1].nonce
, sizeof(keydvt_in
.dnonce
));
452 result
= wusb_key_derive(&keydvt_out
, ck
->data
, &ccm_n
, &keydvt_in
);
454 dev_err(dev
, "Handshake2 failed: cannot derive keys: %d\n",
459 /* Compute MIC and verify it */
460 result
= wusb_oob_mic(mic
, keydvt_out
.kck
, &ccm_n
, &hs
[1]);
462 dev_err(dev
, "Handshake2 failed: cannot compute MIC: %d\n",
467 if (memcmp(hs
[1].MIC
, mic
, sizeof(hs
[1].MIC
))) {
468 dev_err(dev
, "Handshake2 failed: MIC mismatch\n");
472 /* Send Handshake3 */
473 hs
[2].bMessageNumber
= 3;
475 memcpy(hs
[2].tTKID
, &tkid_le
, sizeof(hs
[2].tTKID
));
477 memcpy(hs
[2].CDID
, &wusb_dev
->cdid
, sizeof(hs
[2].CDID
));
478 memcpy(hs
[2].nonce
, hs
[0].nonce
, sizeof(hs
[2].nonce
));
479 result
= wusb_oob_mic(hs
[2].MIC
, keydvt_out
.kck
, &ccm_n
, &hs
[2]);
481 dev_err(dev
, "Handshake3 failed: cannot compute MIC: %d\n",
486 result
= usb_control_msg(
487 usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
488 USB_REQ_SET_HANDSHAKE
,
489 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
490 3, 0, &hs
[2], sizeof(hs
[2]), USB_CTRL_SET_TIMEOUT
);
492 dev_err(dev
, "Handshake3: request failed: %d\n", result
);
496 result
= wusbhc
->set_ptk(wusbhc
, wusb_dev
->port_idx
, tkid
,
497 keydvt_out
.ptk
, sizeof(keydvt_out
.ptk
));
499 goto error_wusbhc_set_ptk
;
501 result
= wusb_dev_set_gtk(wusbhc
, wusb_dev
);
503 dev_err(dev
, "Set GTK for device: request failed: %d\n",
505 goto error_wusbhc_set_gtk
;
508 /* Update the device's address from unauth to auth */
509 if (usb_dev
->authenticated
== 0) {
510 result
= wusb_dev_update_address(wusbhc
, wusb_dev
);
512 goto error_dev_update_address
;
515 dev_info(dev
, "device authenticated\n");
517 error_dev_update_address
:
518 error_wusbhc_set_gtk
:
519 error_wusbhc_set_ptk
:
523 memset(hs
, 0, 3*sizeof(hs
[0]));
524 memzero_explicit(&keydvt_out
, sizeof(keydvt_out
));
525 memzero_explicit(&keydvt_in
, sizeof(keydvt_in
));
526 memzero_explicit(&ccm_n
, sizeof(ccm_n
));
527 memzero_explicit(mic
, sizeof(mic
));
529 wusb_dev_set_encryption(usb_dev
, 0);
530 error_dev_set_encryption
:
537 * Once all connected and authenticated devices have received the new
538 * GTK, switch the host to using it.
540 static void wusbhc_gtk_rekey_work(struct work_struct
*work
)
542 struct wusbhc
*wusbhc
= container_of(work
,
543 struct wusbhc
, gtk_rekey_work
);
544 size_t key_size
= sizeof(wusbhc
->gtk
.data
);
546 struct wusb_dev
*wusb_dev
, *wusb_dev_next
;
547 LIST_HEAD(rekey_list
);
549 mutex_lock(&wusbhc
->mutex
);
550 /* generate the new key */
551 wusbhc_generate_gtk(wusbhc
);
552 /* roll the gtk index. */
553 wusbhc
->gtk_index
= (wusbhc
->gtk_index
+ 1) % (WUSB_KEY_INDEX_MAX
+ 1);
555 * Save all connected devices on a list while holding wusbhc->mutex and
556 * take a reference to each one. Then submit the set key request to
557 * them after releasing the lock in order to avoid a deadlock.
559 for (port_idx
= 0; port_idx
< wusbhc
->ports_max
; port_idx
++) {
560 wusb_dev
= wusbhc
->port
[port_idx
].wusb_dev
;
561 if (!wusb_dev
|| !wusb_dev
->usb_dev
562 || !wusb_dev
->usb_dev
->authenticated
)
565 wusb_dev_get(wusb_dev
);
566 list_add_tail(&wusb_dev
->rekey_node
, &rekey_list
);
568 mutex_unlock(&wusbhc
->mutex
);
570 /* Submit the rekey requests without holding wusbhc->mutex. */
571 list_for_each_entry_safe(wusb_dev
, wusb_dev_next
, &rekey_list
,
573 list_del_init(&wusb_dev
->rekey_node
);
574 dev_dbg(&wusb_dev
->usb_dev
->dev
,
575 "%s: rekey device at port %d\n",
576 __func__
, wusb_dev
->port_idx
);
578 if (wusb_dev_set_gtk(wusbhc
, wusb_dev
) < 0) {
579 dev_err(&wusb_dev
->usb_dev
->dev
,
580 "%s: rekey device at port %d failed\n",
581 __func__
, wusb_dev
->port_idx
);
583 wusb_dev_put(wusb_dev
);
586 /* Switch the host controller to use the new GTK. */
587 mutex_lock(&wusbhc
->mutex
);
588 wusbhc
->set_gtk(wusbhc
, wusbhc
->gtk_tkid
,
589 &wusbhc
->gtk
.descr
.bKeyData
, key_size
);
590 mutex_unlock(&wusbhc
->mutex
);
594 * wusbhc_gtk_rekey - generate and distribute a new GTK
595 * @wusbhc: the WUSB host controller
597 * Generate a new GTK and distribute it to all connected and
598 * authenticated devices. When all devices have the new GTK, the host
601 * This must be called after every device disconnect (see [WUSB]
604 void wusbhc_gtk_rekey(struct wusbhc
*wusbhc
)
607 * We need to submit a URB to the downstream WUSB devices in order to
608 * change the group key. This can't be done while holding the
609 * wusbhc->mutex since that is also taken in the urb_enqueue routine
610 * and will cause a deadlock. Instead, queue a work item to do
611 * it when the lock is not held
613 queue_work(wusbhc
->wq_security
, &wusbhc
->gtk_rekey_work
);